Title: An absorption profile centered at 78 megahertz in the sky-averaged spectrum

Authors: Judd Bowman, Alan Rogers, Raul Monsalve, Thomas Mozdzen & Nivedita Mahesh

First Author’s Institution: School of Earth and Space Exploration, Arizona State University, Tempe, Arizona

Status: Published in Nature [closed access]

Today’s astrobite is about the exciting detection of the 21cm neutral hydrogen emission during the Cosmic Dawn, a topic covered many times in the past (for example here, here, here, oh and here). The 21cm emission from neutral hydrogen has the ability to open up secrets of the early universe and give us some keen insight into how the first stars and galaxies formed and how the universe became reionized. You may be familiar with the cosmic microwave background (CMB) which has provided us with evidence for some of our most important cosmological understandings due to measurements by the satellites COBE, WMAP, and Planck. In much the same way the Experiment to Detect the Global Epoch of Reionization Signature or EDGES (Figure 1) has now done the same for the period between recombination and reionization. So now let’s jump into why this detection is so amazing and how there may potentially be some new underlying physics at work.

Figure 1: The Experiment to Detect the Epoch of Reionization Signature (EDGES) single antenna radio telescope. Situated in Western Australia at the Murchison Radio Astronomy Observatory.

The Global 21cm neutral hydrogen emission

To get a good understanding of the detection, let’s break down exactly what constitutes the global 21cm neutral hydrogen signal. The 21cm (1420 MHz) emission occurs from the forbidden spin-flip transition of neutral hydrogen, which gets stretched by cosmological redshift to lengths of meters. We say ‘forbidden’ because the time-scale for the probability of a single hydrogen atom undergoing this transition is on the order of megayears. Luckily when trying to observe this emission we are doing so in bulk, (there is a lot of hydrogen in the universe) so it’s not an impossible task. Another important point is that the neutral hydrogen (and also it’s signal) is strongly coupled to the CMB, for example looking to Figure 2 (bottom), neutral hydrogen and the CMB are at the same temperature everywhere that thedifferential brightness temperature is zero.

Figure 2: The global 21cm neutral hydrogen signal over redshift (and frequency) where the top image is the spatially fluctuating 21cm neutral hydrogen and the bottom is the globally averaged 21cm signal. The 21cm signal is strongly coupled to the CMB, which means it is undetectable until the temperature of the neutral hydrogen deviates from the CMB. Borrowed from http://pritchardjr.github.io/research.html.

Ok, so now we have some basics down and we know that the global 21cm signal is just the average of the 21cm signal over large scales. Now what exactly do we need to use to detect this global signal? Can we use a radio interferometer (e.g. HERA, MWA, and LOFAR)? Unfortunately not. Radio interferometers are insensitive to the globally averaged signal, and are better suited for trying to detect the spatial fluctuations (Figure 2 top). You therefore need to use a wideband single antenna radio telescope; and you want it to be wideband because the early global 21cm signature occurs over a redshift range of 13 < z < 27 which corresponds to the frequencies of 50 – 100 MHz.

The Detection

Figure 3: (a) The EDGES sky measurement in units of brightness temperature, showing the strong power-law spectrum due to galactic synchrotron emission. (b) Residuals after removing the power-law dependence. (c) Residuals after removing the power-law synchrotron emissions in addition to a model (d) of the 21cm absorption signal. (e) Residuals from (c) added to model in (d).

The two biggest issues with detecting this faint signal are to do with calibration of the instrument, and galactic synchrotron emission. To try and compensate for introducing false signals added to their measurements due to calibration of the instrument, the author’s separately apply two different calibration techniques. This ensures that a detection seen in one calibrated measurement should be also present in the other differently calibrated measurement. The other problem is due to incredibly bright synchrotron emission, which appears to be almost 4 orders of magnitude larger than the signal! To account for this the authors depend on the fact that these foreground emissions should be smooth over frequency, meaning you can fit and subtract out a low-order polynomial from this measurement and ideally there should be no loss of signal. They fit a 4th-order polynomial and the residuals look like those seen in Figure 3(b). They then simultaneously fit the 4th order polynomial with a model of an expected 21cm signal (for many realizations of a 21cm signal). Their best fit model is demonstrated in Figure 3(d), and the residuals from the combined fit (polynomial + 21cm model) in Figure 3(c). From this measurement they detect an absorption profile centered at 78 MHz (z ~ 17) over 19 MHz with an amplitude of -500 mK. This now leads us to an interesting consequence concerning the amplitude of the absorption, represented by the depth of the troughs in Figures 3(d-e), which is over a factor of 2 larger than originally expected. This is where we can begin to introduce dark matter.

Implications for Dark Matter

Our original understanding of the amplitude for this absorption profile is limited by the minimum temperature of neutral hydrogen that can be achieved by adiabatic cooling due to cosmic expansion. Based on this measurement which appears to be twice as large as expected, we are led to believe there must be an additional mechanism that is cooling the neutral hydrogen below this adiabatic limit (there is another explanation which states that the background radiation temperature could have been hotter but dark matter is more fun). So how does dark matter come into play? In general, for the neutral hydrogen to become cooler it must come into contact with something even colder. This implies that through interactions such as baryons scattering with dark matter particles it can drive down the temperature leading to the larger amplitude absorption profile. These relative scattering velocities also place constraints on important dark matter particle parameters such as the mass and cross-section (check out this primer). By looking at the minimum temperature achieved by cooling from both cosmic expansion and dark matter interactions, theorists (companion dark matter paper released same day) were able to place constraints on both these parameters which give us a cross-section, and a particle mass  , in the ~1 GeV range. Of course all of this should be taken with a healthy skepticism but the idea of using 21cm observations to constrain dark matter is truly promising.

The Future of 21cm Observations

This is most certainly an exciting detection which opens up many more questions than it answers. The next order of business is to confirm the initial detection by EDGES, either by another single antenna global 21cm experiment or by measuring the spatially fluctuating 21cm signal using an interferometer around the same redshift range as EDGES. By getting additional instruments to measure this period, the role of dark matter in cooling baryons in the early universe can either be ruled out or as it appears as of right now provide a useful probe into their detection. Either way, the Cosmic Dawn is hiding many more secrets for us to discover.

I'm Kevin, co-founder of Pathrise (https://www.pathrise.com). Pathrise is an online replacement for career services that helps students get better jobs and make more money. If and only if they get hired during our program, students pay us back a tuition fee of 7% of their income for 1 year.

For more context, you can read about us here: https://venturebeat.com/2018/03/09/pathrise-wants-to-be-the-....

The problem: universities aren't directly incentivized to get students good jobs since they make all their money in upfront tuition. As a result, college career services centers aren't results-driven and can't properly support their students. Most students are essentially left to figure things out on their own, and they think to themselves, career services are useless. The easiest way to verify this is to ask your average student how many times they've visited their career services center in the last year.

In reality, career services (that actually work) are probably one of the highest value things a student can receive. You can take any step of the job search (e.g. online applications), train students on one technique (e.g. lead gen and cold emailing), and produce significant and measurable returns (e.g. we've measured that this technique in particular can 4X response rate from under 5% to over 20%). Pathrise does this with every step of the job-hunting process, from training students from a 2/6 to a 5/6 in technical interviewing scores based on real company rubrics to helping students get a 10%+ higher salary through negotiation.

In this sense, we're kind of like YC for students instead of startups. Founders give 7% equity to YC because they know YC will increase their company's prospects by more than 7%. Students give us 7% of their first year's income, and our program is designed to increase their job prospects by more than 7%. They know we'll do everything in our power to provide them that value because we have aligned incentives - we only make money if they do.

What this ends up looking like is an online accelerator for students that takes place in 12 monthly batches a year, followed by an average of 3-4 months of support until a student is placed. Instead of focusing on a technical education (like our friends at Lambda School), Pathrise is entirely about optimizing your job search. This involves services like resume review, prospecting, referrals, interview preparation, and negotiation advice. Again, unlike career services today, we track every data point so we can hold ourselves accountable to actually produce significant and measurable value for our students.

Thanks for reading! I'd be happy to answer any of your questions and would greatly appreciate your feedback.

If you’ve ever read a git man page, you’ll know that trying to understand git can be an intimidating experience.

There’s even a git man page generator that produces joke git pages:

If <upstream> is not specified, the upstream configured in
branch.<name>.remote and branch.<name>.merge options will be used 
(see git-config(1) for details) and the --fork-point option is 
assumed. If you are currently not on any branch or if the current
branch does not have a configured upstream, the rebase will abort.

git-land-remote lands some applied remotes over the packed applied
branches, and it is in various cases a possibility that a
filter-branched error must prevent staged cleaning of some named
stages.

One of the above extracts is a joke, one is real…

So here’s five core git concepts explained.

Hopefully after reading this the man pages will start to make more sense. If you’re confused by one I’ve missed, contact me to write it up for you (@ianmiell or LinkedIn).

This post uses the ‘hard way‘ method to teach the concepts by having you type out the commands and think through what’s going on, without having to worry about breaking anything.

I use the same method to teach git in my book Learn Git the Hard Way.    

1) Reference

Many will know this already, but I need to make sure you know it because it’s so fundamental.

A ‘reference’ is a string that points to a commit.

There are four main types of reference: HEAD, Tag, Branch, and Remote Reference

HEAD

HEAD is a special reference that always points to where the git repository is.

If you checked out a branch, it’s pointed to the last commit in that branch. If you checked out a specific commit, it’s pointed to that commit. If you check out at a tag, it’s pointed to the commit of that tag.

Every time you commit, the HEAD reference/pointer is moved from the old to the new commit. This happens automatically, but it’s all going on under the hood.

Tag

A tag is a reference that points to a specific commit. Whatever else happens (and unlike the HEAD), that tag will stay pointed at the commit it was originally pointed at.

Branch

A branch is like a tag, but will move when the HEAD moves.

You can only be on one branch at a time.

Type out these commands and explain what’s going on. Take your time:

$ mkdir lgthw_origin
$ cd lgthw_origin
$ git init
$ echo 1 > afile
$ git add afile
$ git commit -m firstcommit
$ git log --oneline --decorate --all --graph
$ git branch otherbranch
$ git tag firstcommittag
$ git log --oneline --decorate --all --graph
$ echo 2 >> afile
$ git commit -am secondcommit
$ git checkout otherbranch
$ git log --oneline --decorate --all --graph
$ echo 3 >> afile
$ git commit -am thirdcommit
$ git log --oneline --decorate --all --graph

Now do it again and explain to someone else what’s going on.

Remote Reference

A remote reference is a reference to code that’s from another repository. See below for more on that…

2)  ‘Detached Head’

Now that you know what HEAD is, then understanding what a ‘detached head’ is will be much easier.

A ‘detached head’ is a git repository that’s checked out but has no branch associated with it.

Continuing from the above listing, type this in:

$ git checkout firstcommittag

You get that scary message:

Note: checking out 'firstcommit'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

git checkout -b <new-branch-name>

HEAD is now at 1b1499c... firstcommit

but if you follow the instructions:

$ git log --oneline --decorate --all --graph
$ git checkout -b firstcommitbranch
$ git log --oneline --decorate --all --graph

you can figure out what’s going on. There was a tag, but no branch at that commit, so the HEAD was detached from a branch.

3) Remote Reference

A remote reference is a reference to a commit on another git repository.

$ cd ..
$ git clone lgthw_origin lgthw_cloned
$ cd lgthw_cloned
$ git remote -v
$ git log --oneline --decorate --all --graph

The log graph looks different doesn’t it?

Compare that to the ​git log output in the other folder and think about how they differ. What word do you see multiple times in the output that you didn’t see before?

The cloned repo has its own copy of the branch (firstcommitbranch) and tag (firstcommit) because that’s where the repository’s HEAD was when you cloned it.

$ git branch -a

shows all the branches visible in this repository, both local and remote.

Compare that to the output of the same command in the original folder. How does it differ?

Now check out your local master:

$ git checkout master

and you get a message saying:

Branch master set up to track remote branch master from origin.Switched to a new branch 'master'

So you’ve got a local reference master which ‘tracks’ the master in the remote repository. The local reference is master, and the remote reference is origin/master. Git assumed you meant your local master to track the remote master.

The two branches look the same, but they are linked only by the configuration of this repository.

$ cd ../lgthw_origin
$ git checkout master$ echo origin_change >> afile$ git commit -am 'Change on the origin'

Then go back to the cloned repository and fetch the changes from the origin:

$ cd ../lgthw_cloned$ git fetch origin$ git log --oneline --decorate --all --graph

Can you see what happened to your local master branch, and what happened to the origin’s? Why are they now separate?

Note that you didn’t git pull the change. git pull does a fetch and a merge, and we don’t want to confuse here by skipping steps and making it look like magic.

In fact, git pull is best avoided when you are learning git…

If you like this post, you’ll like my book Learn Git the Hard Way

It covers all this and much more in a similar style.

4) Fast Forward

Your git log graph should have looked like this:

* 90694b9 (origin/master) Change on the origin* d20fc9a (HEAD -> master) secondcommit
| * 2e7ae21 (origin/otherbranch) thirdcommit
|/ 
* 6c14f2f (tag: firstcommittag, origin/firstcommitbranch, origin/HEAD, firstcommitbranch) firstcommit

(Your ids may differ from the above – otherwise it should be the same.)

Now, do you see how the Change on the origin commit is not branched from your local HEAD/master commit secondcommit – it’s in a ‘straight line’ from the firstcommit tag?

That means that if you ‘merge’ origin/master into your local master, git can figure out that all it needs to do is move the HEAD and master reference to where the origin/master branch is and its ‘merge’ job is done.

$ git merge origin/master
$ git log --oneline --decorate --all --graph

This is all a ‘fast forward’ is: git saw that there’s no need to do any merging, it can just ‘fast forward’ the references to the point you are merging to. Or if you prefer, it just moves the pointers along rather than create a new merge commit.

We just did a git pull, by the way. A git pull consists of a git fetch and a git merge. Breaking it down into these two steps helps reduce the mystery of why things can go wrong.

As an exercise, after finishing this article do the whole exercise again, but make a change to both origin/master and master and then do the fetch and merge to see what happens when a fast-forward is not possible.

5) Rebase

master and origin/master are now in sync, so now run these commands to see what a rebase is:

$ cd ../lgthw_origin $ git status$ echo origin_change_rebase >> afile $ git commit -am 'origin change rebase' $ git log --oneline --decorate --all --graph 

OK so far? You’ve made a change on master on the origin repo:

$ cd ../lgthw_cloned $ echo cloned_change_rebase >> anewfile $ git add anewfile $ git commit -m 'cloned change rebase in anewfile' $ git log --oneline --decorate --all --graph $ git fetch origin $ git log --oneline --decorate --all --graph $ git rebase origin/master $ git log --oneline --decorate --all --graph

Can you see what’s happened?

If not, have a close look at the last two git log outputs.

That’s what a rebase is – it takes a set of commits and moves (or ‘re-bases’) them to another commit.

If you liked this post, you’ll like my book Learn Git the Hard Way

It covers all this and much more in a similar style.

If you liked this post, you might also like these:

Create your own Git diagrams

A Git Serverless Pattern

Power Git Log Graphing

Interactive Git Rebase and Bisect Tutorials

The Securities and Exchange Commission today charged Silicon Valley-based private company Theranos Inc., its founder and CEO Elizabeth Holmes, and its former President Ramesh “Sunny” Balwani with raising more than $700 million from investors through an elaborate, years-long fraud in which they exaggerated or made false statements about the company’s technology, business, and financial performance.  Theranos and Holmes have agreed to resolve the charges against them.  Importantly, in addition to a penalty, Holmes has agreed to give up majority voting control over the company, as well as to a reduction of her equity which, combined with shares she previously returned, materially reduces her equity stake.

The complaints allege that Theranos, Holmes, and Balwani made numerous false and misleading statements in investor presentations, product demonstrations, and media articles by which they deceived investors into believing that its key product – a portable blood analyzer – could conduct comprehensive blood tests from finger drops of blood, revolutionizing the blood testing industry.  In truth, according to the SEC’s complaint, Theranos’ proprietary analyzer could complete only a small number of tests, and the company conducted the vast majority of patient tests on modified and industry-standard commercial analyzers manufactured by others.

The complaints further charge that Theranos, Holmes, and Balwani claimed that Theranos’ products were deployed by the U.S. Department of Defense on the battlefield in Afghanistan and on medevac helicopters and that the company would generate more than $100 million in revenue in 2014.  In truth, Theranos’ technology was never deployed by the U.S. Department of Defense and generated a little more than $100,000 in revenue from operations in 2014.

“Investors are entitled to nothing less than complete truth and candor from companies and their executives,” said Steven Peikin, Co-Director of the SEC’s Enforcement Division.  “The charges against Theranos, Holmes, and Balwani make clear that there is no exemption from the anti-fraud provisions of the federal securities laws simply because a company is non-public, development-stage, or the subject of exuberant media attention.”

“As a result of Holmes’ alleged fraudulent conduct, she is being stripped of control of the company she founded, is returning millions of shares to Theranos, and is barred from serving as an officer or director of a public company for 10 years,” said Stephanie Avakian, Co-Director of the SEC’s Enforcement Division.  “This package of remedies exemplifies our efforts to impose tailored and meaningful sanctions that directly address the unlawful behavior charged and best remedies the harm done to shareholders.”

“The Theranos story is an important lesson for Silicon Valley,” said Jina Choi, Director of the SEC’s San Francisco Regional Office.  “Innovators who seek to revolutionize and disrupt an industry must tell investors the truth about what their technology can do today, not just what they hope it might do someday.”

Theranos and Holmes have agreed to settle the fraud charges levied against them.  Holmes agreed to pay a $500,000 penalty, be barred from serving as an officer or director of a public company for 10 years, return the remaining 18.9 million shares that she obtained during the fraud, and relinquish her voting control of Theranos by converting her super-majority Theranos Class B Common shares to Class A Common shares.  Due to the company’s liquidation preference, if Theranos is acquired or is otherwise liquidated, Holmes would not profit from her ownership until – assuming redemption of certain warrants – over $750 million is returned to defrauded investors and other preferred shareholders.  The settlements with Theranos and Holmes are subject to court approval.  Theranos and Holmes neither admitted nor denied the allegations in the SEC’s complaint.  The SEC will litigate its claims against Balwani in federal district court in the Northern District of California.

The SEC’s investigation was conducted by Jessica Chan, Rahul Kolhatkar, and Michael Foley and supervised by Monique Winkler and Erin Schneider in the San Francisco Regional Office.  The SEC’s litigation will be led by Jason Habermeyer and Marc Katz of the San Francisco office.

README.md

Exactly today (Dec. 26th 2016) I haven’t had a single drop of alcohol or coffee in 27 months. If you're reading this later, you can do the math yourself.

A couple of my friends on Facebook & Twitter asked me to write about my experience, so here it is, in a nutshell.

With over a year of no alcohol & coffee, I did notice some side effects. Here is what I learned.

I save $1000 every month

After 2 months I noticed that I had $1000 more on my bank account. Yes, that’s a lot, but do the math and you notice it’s not that much.

I live in New York. In order to spend $1000 on alcohol I only have to spend $33 everyday. Assume that I have 2–3 cocktails every other day (which are $10 each without tip), including some wine bottles every month for at home I can easily spend $1000.

Some might think that this is heavy alcoholism, but trust me when I say that having 1–2 drinks everyday in New York is more than normal.

Also, going out drinking means that the occasional dinner & snacks are more frequent. You don’t just drink, you get hungry and buy some food. And before you noticed it, you spend $1000.

Less gossip

If there is one thing I noticed quite early, then it’s the lack of social interaction my new diet brought with it. Here is what happened:

• You don’t really go out anymore. It’s exhausting to explain again and again why you don’t drink and NO also one drink is not okay.
  When a group of people asks me to join them for drinks, I mostly default to answer with NO because I just don’t want to deal with gossip as a sober person.
• If I do go for drinks, I last max. 1 hour because this is how long my attention span as a sober person lasts in a group of drunk people.
• While I was never a party animal anyways, completely stopping with alcohol made me go out even less. It’s amazing to see the culture of drinking slowly fading away from your life. It made me realize how many friendships are actually based mostly on your drinking habits.

“Let’s go for a drink” is so engraved in our lives, because who says “Hey, let’s just meet up as sober people and talk about stuff” — Why the fuck would you do that? “Let’s get a drink” needs no explanation. It’s a thing, everyone knows what happens next.

My sleep quality increased

Removing alcohol from my diet increased my sleep quality drastically. And I’m not talking about “falling asleep” but the actual sleep quality.

You sure do fall asleep easier with 1–2 glasses of beer or wine, but the actual sleep quality might suffer. I sleep better, and I wake up with more energy. Before I always ruined my mornings, even if I only had two beers at night I could feel it in the morning. (if you’re in your early twenties, ignore this, it doesn’t affect you yet)

No coffee, less panic, less stress

This might be something more personal and not related to everyone. But removing coffee from my diet helped me become more relaxed. Coffee always made me stressed out. It increased my chance of having anxiety and also fucked up my digestion. Removing coffee/caffeine from my diet not only made me more relaxed, I also poop like a king.

Besides that, I love the smell and taste of coffee. An occasional decaf will do the trick. In the summer I now drink ice tea, in the winter regular tea.
I found out that “Going for a coffee” turned out to be more of a social activity than the actual craving for coffee. Keep the social habit, replace coffee with something else.

__

Overall, I’m very happy about my decision and have no desire to start drinking again. I’m also not telling you to do the same, if you’re happy with how things are going, don’t change anything.

I changed my habits out of curiosity and I like how it turned out.

PS: Before someone asks. I do not smoke cigarettes. I also don’t smoke weed. I also don’t take any drugs whatsoever. (I have Internet, that’s addiction enough for me)

Yours truly,
Tobias

Today I have some sad news for you, the community. Recently we have communicated with Bethesda regarding our planned method to implement the voice acting and other audio from Fallout 3 Into the Capital Wasteland. During this Conversation it became clear our planned approach would raise some serious red flags that we had unfortunately not foreseen .This contact resulted in us changing our methods to attempt to continue working.

After some thought it appears there is no fully Legal way for us to continue developing the Fallout 3 in Fallout 4 Portion of The Capital Wasteland. Projects like these have always existed in a Gray area of the law but we as a team value our connections with many members of the amazing dev team that is Bethesda Game studios.

To Reinforce my point, The Laws around this have not changed. If we were to continue and complete Fallout 3 in Fallout 4 Legally I as the project lead would most probably be Liable for any acts of Piracy and Copyright infringement resulting from the projects release. My self and the Road to Liberty team do not wish to strain the working relationships with other members of the community and Bethesda.

At first we were very reluctant to halt work and decided to start looking into Re recording all the Voice acting. We quickly realised we would have to replace iconic voices like Liam Neeson, Malcom McDowell,Ron Perlman and of course the phenomenal Eric Todd Dellums. Without some of these voices fallout 3 looses its charm and personally I cant bring my self to replace Them.

If at any point in the future it becomes fully legal for us to continue working with the blessing of Bethesda and Zenimax we will.

This decision was not taken lightly and it pains many people on my team including my self to have to halt development of the Fallout 3 Story. I personally would like to apologise to the many members of the community that love Fallout 3 as much as I do. Im sorry we couldn't accomplish our dream.

This tutorial is intended for someone who wants to understand how Recurrent Neural Network works, no prior knowledge about RNN is required. We will implement the most simple RNN model – Elman Recurrent Neural Network. To get a better understanding of RNNs, we will build it from scratch using Pytorch tensor package and autograd library.

I assume that you have some understanding of feed-forward neural network if you are new to Pytorch and autograd library checkout my tutorial.

Elman Recurrent Neural Network

An Elman network was introduced by Jeff Elman, and was first published in a paper entitled Finding structure in time.  It’s just a  three-layer feed-forward network, in our case, input layer consist of one input neuron \(x_{1}\)  and additional units called context neurons \(c_{1}\) … \(c_{n}\). Context neurons receive input from the hidden layer neurons, from previous time step. We have one context neuron per neuron in the hidden layer. Since the state from previous time step is provided as a part of the input, we can say that network has a form of memory, context neurons represent a memory.

Predicting the sine wave

We will train our RNN to learn sine function. During training we will be feeding our model with one data point at a time, that is why we need only input neuron  \(x_{1}\), and we want to predict the value at next time step. Our input sequence x consists of 20 data points, and the target sequence is the same as the input sequence but it ‘s shifted by one-time step into the future.

Implementing the model

We start by importing the necessary packages.

Next, we’ll set the model hyperparameters,  the size of the input layer is set to 7, which means that we will have 6 context neurons and 1 input neuron, seq_length defines the length of our input and target sequence.

Now we will generate the training data, where x is an input sequence and y is a target sequence.

We need to create two weight matrices, w1 of size (input_size, hidden_size) for input to hidden connections, and a w2 matrix of size (hidden_size, output_size) for hidden to output connection. Weights are initialized using a normal distribution with zero mean.

We can now define forward pass method, it takes input vector x, context_state vector and two weights matrices as arguments. We will create vector xh by concatenating input vector x with the context_state vector. We perform dot product between the xh vector and weight matrix w1, then apply tanh function as nonlinearity, which works better with RNN than sigmoid. Then we perform another dot product between new context_state and weight matrix w2. We want to predict continuous value, so we do not apply any nonlinearity at this stage.

Note that context_state vector will be used to populate context neurons at the next time step. That is why we return context_state vector along with the output of the network.

This is where the magic happens, context_state vector summarizes the history of the sequence it has seen so far.

Training

Our training loop will be structured as follows.

• The outer loop iterates over each epoch. Epoch is defined as one pass of all training data.  At the beginning of each epoch, we need to initialize our context_state vector with zeros.
• The inner loop runs through each element of the sequence. We run forward method to perform forward pass which returns prediction and context_state which will be used for next time step. Then we compute Mean Square Error (MSE),  which is a natural choice when we want to predict continuous values.  By running backward() method on the loss we calculating gradients, then we update the weights. We’re supposed to clear the gradients at each iteration by calling zero_() method otherwise gradients will be accumulated. The last thing we do is wrapping context_state vector in new Variable, to detach it from its history.

The output generated during training shows how the loss is decreasing with every epoch, which is a good sign. Decaying loss means that our model is learning.

Epoch: 0 loss 2.777482271194458
Epoch: 10 loss 0.10264662653207779
Epoch: 20 loss 0.1178232803940773
…
Epoch: 280 loss 0.005524573381990194
Epoch: 290 loss 0.005174985621124506

Making Predictions

Once our model is trained, we can make predictions, at each step of the sequence we will feed the model with single data point and ask the model to predict one value at the next time step.

As you can see, our model did a pretty good job.

Conclusion

In this post we’ve implemented a basic RNN model from scratch using Pytorch. We learn how to apply RNN to simple sequence prediction problem. The full code is available on Github.

California earthquakes are a geologic inevitability. The state straddles the North American and Pacific tectonic plates and is crisscrossed by the San Andreas and other active fault systems. The magnitude 7.9 earthquake that struck off Alaska’s Kodiak Island on Jan. 23, 2018 was just the latest reminder of major seismic activity along the Pacific Rim. Tragic quakes that occurred in 2017 near the Iran-Iraq border and in central Mexico, with magnitudes of 7.3 and 7.1, respectively, are well within the range of earthquake sizes that have a high likelihood of occurring in highly populated parts of California during the next few decades.

The earthquake situation in California is actually more dire than people who aren’t seismologists like myself may realize. Although many Californians can recount experiencing an earthquake, most have never personally experienced a strong one. For major events, with magnitudes of 7 or greater, California is actually in an earthquake drought. Multiple segments of the expansive San Andreas Fault system are now sufficiently stressed to produce large and damaging events.

The good news is that earthquake readiness is part of the state’s culture, and earthquake science is advancing – including much improved simulations of large quake effects and development of an early warning system for the Pacific coast.

The last big one

California occupies a central place in the history of seismology. The April 18, 1906 San Francisco earthquake (magnitude 7.8) was pivotal to both earthquake hazard awareness and the development of earthquake science – including the fundamental insight that earthquakes arise from faults that abruptly rupture and slip. The San Andreas Fault slipped by as much as 20 feet (six meters) in this earthquake.

Although ground-shaking damage was severe in many places along the nearly 310-mile (500-kilometer) fault rupture, much of San Francisco was actually destroyed by the subsequent fire, due to the large number of ignition points and a breakdown in emergency services. That scenario continues to haunt earthquake response planners. Consider what might happen if a major earthquake were to strike Los Angeles during fire season.

Seismic science

When a major earthquake occurs anywhere on the planet, modern global seismographic networks and rapid response protocols now enable scientists, emergency responders and the public to assess it quickly – typically, within tens of minutes or less – including location, magnitude, ground motion and estimated casualties and property losses. And by studying the buildup of stresses along mapped faults, past earthquake history, and other data and modeling, we can forecast likelihoods and magnitudes of earthquakes over long time periods in California and elsewhere.

However, the interplay of stresses and faults in the Earth is dauntingly chaotic. And even with continuing advances in basic research and ever-improving data, laboratory and theoretical studies, there are no known reliable and universal precursory phenomena to suggest that the time, location and size of individual large earthquakes can be predicted.

Major earthquakes thus typically occur with no immediate warning whatsoever, and mitigating risks requires sustained readiness and resource commitments. This can pose serious challenges, since cities and nations may thrive for many decades or longer without experiencing major earthquakes.

California’s earthquake drought

The 1906 San Francisco earthquake was the last quake greater than magnitude 7 to occur on the San Andreas Fault system. The inexorable motions of plate tectonics mean that every year, strands of the fault system accumulate stresses that correspond to a seismic slip of millimeters to centimeters. Eventually, these stresses will be released suddenly in earthquakes.

But the central-southern stretch of the San Andreas Fault has not slipped since 1857, and the southernmost segment may not have ruptured since 1680. The highly urbanized Hayward Fault in the East Bay region has not generated a major earthquake since 1868.

Reflecting this deficit, the Uniform California Earthquake Rupture Forecast estimates that there is a 93 percent probability of a 7.0 or larger earthquake occurring in the Golden State region by 2045, with the highest probabilities occurring along the San Andreas Fault system.

Can California do more?

California’s population has grown more than 20-fold since the 1906 earthquake and currently is close to 40 million. Many residents and all state emergency managers are widely engaged in earthquake readiness and planning. These preparations are among the most advanced in the world.

For the general public, preparations include participating in drills like the Great California Shakeout, held annually since 2008, and preparing for earthquakes and other natural hazards with home and car disaster kits and a family disaster plan.

Nonetheless, California’s infrastructure, response planning and general preparedness will doubtlessly be tested when the inevitable and long-delayed “big ones” occur along the San Andreas Fault system. Ultimate damage and casualty levels are hard to project, and hinge on the severity of associated hazards such as landslides and fires.

Several nations and regions now have or are developing earthquake early warning systems, which use early detected ground motion near a quake’s origin to alert more distant populations before strong seismic shaking arrives. This permits rapid responses that can reduce infrastructure damage. Such systems provide warning times of up to tens of seconds in the most favorable circumstances, but the notice will likely be shorter than this for many California earthquakes.

Here a simulation of the most likely scenario and effects for the next big earthquake (M7.8) in Southern California:

Early warning systems are operational now in Japan, Taiwan, Mexico and Romania. Systems in California and the Pacific Northwest are presently under development with early versions in operation. Earthquake early warning is by no means a panacea for saving lives and property, but it represents a significant step toward improving earthquake safety and awareness along the West Coast.

Managing earthquake risk requires a resilient system of social awareness, education and communications, coupled with effective short- and long-term responses and implemented within an optimally safe built environment. As California prepares for large earthquakes after a hiatus of more than a century, the clock is ticking.

Yes, get ready and be prepared the the next Big Ones!

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The Conversation

The text from the Equifax Inc. executive sounded ominous: “We may be the one breached.”

Yet before the wider world learned of the credit bureau’s massive hack -- in which sensitive information for more than 140 million U.S. consumers had been compromised -- the executive, Jun Ying, was selling Equifax stock, federal authorities now say.

Six months after the cyberattack shook Equifax and raised questions about suspicious trading by several executives there, the Department of Justice on Wednesday charged Ying with insider trading. Prosecutors say he searched on the internet for what might happen to Equifax stock when the news of the attack broke, then exercised all of his stock options. The move netted him more than $480,000. Ying’s lawyers, Douglas I. Koff and Craig S. Warkol of Schulte Roth & Zabel, declined to comment on Ying’s behalf.

Wednesday’s announcement marks the first criminal charge brought in one of the largest data breaches in history. Ying, the former chief information officer for Equifax’s U.S. information-solutions business, used confidential information entrusted to him by the company to determine it had been hacked, according to a separate complaint filed by the Securities and Exchange Commission.

Equifax interim Chief Executive Officer Paulino do Rego Barros said in a statement Wednesday that the company reviewed Ying’s trading and, after concluding he violated the firm’s policies, reported its findings to government authorities. “We are fully cooperating with the DOJ and the SEC, and will continue to do so,” Barros said.

Sale Timeline

Ying, 42, lives in Atlanta and worked at Equifax from 2013 until last October. On Friday, Aug. 25, he received an email asking him to handle breach remediation for an internal project code-named Sparta. The email stated that Equifax’s global consumer-solutions business was working on a “VERY large breach opportunity” and that the request was “extremely time sensitive,” according to the SEC’s complaint.

Hours after receiving the initial email, Ying was invited to a mandatory conference call. While he didn’t initially join the call, one of his direct reports did, the SEC said. That person texted Ying that he’d been asked to help prepare the IT applications they oversaw to handle roughly 10 million customers. Ying then joined the conference call, initially resisting the requests to assist on the project.

When Ying talked privately with his supervisor, the manager’s message was cryptic: He told Ying he didn’t need to know why he had to comply with Project Sparta at that time, but at some point he would come to understand what was happening.

Ying then texted the direct report, according to the complaint. “Sounds bad. We may be the one breached,” he wrote. “Starting to put 2 and 2 together.”

The following Monday, he conducted web searches about the impact of Experian Plc’s 2015 data breach on its stock price, the agency found. Hours later, Ying exercised all of his available stock options, resulting in him receiving 6,815 shares of Equifax stock. He then sold the stock for more than $950,000.

Equifax’s Plunge

The following week, Equifax disclosed the cyberattack. The hack has shaken confidence in the Atlanta-based company, which faces more than 240 class-action lawsuits and more than 60 regulatory or government inquiries.

For more on cybersecurity, check out the Decrypted podcast: 

Equifax stock plunged in the days after the breach was disclosed. Ying, who was next in line to become the company’s global CIO, avoided more than $117,000 of losses by selling his shares, the SEC said.

In its complaint, the SEC said Equifax offered Ying the job of global CIO on Sept. 15. The company then rescinded the promotion after senior executives learned of his stock trading. Equifax concluded on Oct. 16 that Ying had violated the company’s insider-trading policy and that he should be terminated, prompting his resignation, the SEC said.

In September, Justice opened a criminal investigation into whether top officials at Equifax had violated insider trading laws before the breach was disclosed. Three Equifax Inc. senior executives -- Chief Financial Officer John Gamble, and unit presidents Joseph Loughran and Rodolfo Ploder -- sold shares worth almost $1.8 million in the days after the company discovered the breach. Equifax has said those three executives had not been informed of the incident when they initiated the sales.

Ying’s stock sale hadn’t been previously reported because he wasn’t a named executive officer.

— With assistance by Anders Melin

S. 2383

To amend title 18, United States Code, to improve law enforcement access to data stored across borders, and for other purposes.

To amend title 18, United States Code, to improve law enforcement access to data stored across borders, and for other purposes.

(written by lawrence krubner, however indented passages are often quotes). You can contact lawrence at: lawrence@krubner.com

Just to get this out of the way, entrepreneurs engage in all of the self-destructive habits that non-entrepreneurs sometimes engage in: drug addiction, denial, blame shifting, perfectionism, depression, mania, laziness, etc. I’m not going to write about that, because all of that is too obvious, and great essays have already been written about those subjects. Instead I’m going to write about the self-destructive habits that are unique to entrepreneurs. There are 3 patterns that I have seen a lot of:

1.) A product or service begins to gain a following with a small niche. The entrepreneur is heartbroken. They can not see any way to move beyond that niche. They had dreamed that their startup would grow till it was larger than Google, therefore success with a small niche is disappointing.

2.) A startup achieves a success of a conventional type and, therefore, the entrepreneur regards it as boring. Perhaps the site was suppose to pioneer an altogether new style of interaction among humans, and instead the part of the startup that becomes popular is of an old type – for instance, the company blog becomes highly popular. The entrepreneur is then disappointed, maybe even angry, to be the owner of a boring success.

3.) The entrepreneur will have to engage in new areas of activity which make them uncomfortable. For instance, a software engineer comes up with cool software that has real utility for an industry. To achieve success, the engineer must either become a salesperson, or raise money from investors so that they can hire a salesperson. But the engineer is not comfortable with sales, nor are they comfortable talking to investors. What they are comfortable doing is working on their software, so they continue doing that. Afternoons are spent at co-working spaces where clever new features are added. The software gets better and better, but without the structure of a company dedicated to promoting it, it languishes in obscurity.

The above is the summary. Below I’ll expand on these 3 destructive forms of self-sabotage

A product or service gains a following with a small niche

Peter Drucker, perhaps the greatest business guru of the 20th Century, once remarked that innovators are often disappointed by the manner in which their innovations become popular. In his 1985 book, Innovation and Entrepreneurship, Drucker relates the story of Alfred Einhorn, who invented Novocain, which then became popular with dentists as a local anesthetic. Einhorn held a contempt for dentistry, since it was such a small market. He felt that Novocain should be used by surgeons for all forms of surgery. General surgery was more prestigious than dentistry, and so Einhorn waged a campaign against the use of Novocain by dentists. In the end, his innovation was successful despite him, rather than because of him. According to Drucker, this pattern, where a product is undercut by the entrepreneur who created it, is extremely common.

When I first read Drucker’s book I found it hard to believe that an entrepreneur would actively sabotage their own innovation. However, having now spent almost 20 years working with startups, I’ve seen that it is, indeed, a common pattern.

There is a lot of power to be had from starting with a small niche. When Facebook started in 2004, it had no hope of competing directly with MySpace. Being exclusive to universities gave Facebook a niche where it could build up momentum, before opening up to the general public.

I talk to a lot of entrepreneurs who worry that if they focus on a small niche, the market opportunity will be too small to interest investors. My response is “It is better to own 1% of something than to own 100% of nothing.” If starting with a niche means success, whereas going after the general market means failure, then starting with a niche is the right answer. And with tech startups, this applies nearly always.

A startup achieves a success of a conventional type

From 2002 to 2008, I worked with an entrepreneur who was a bit of a dreamer. He considered himself a visionary, someone who understood the future. He read history, pop culture, art, science and tech — he complimented himself on his ability to synthesize different types of information. I credit him with being very creative, but also torn apart by some internal contradictions. He insisted that he was unconventional, and he wanted the world to acknowledge that his creativity grew out of his non-conformism. In particular, he had a need to impress his father, and to get his father to acknowledge that unconventional paths could also be highly successful. We burned through several million dollars on several ideas, any of one of which could have been a success — but each of which felt too ordinary for him, causing him to lose interest. After several years of working together, we had a modest success, when we built the iHanuman yoga site. The site was immediately profitable, and it remains so even now, 9 years later. If you are looking to buy instructional videos about yogo, the site is a wonderful resource. I suggested that we use the same technology to build a whole series of websites focused on different topics, such as cooking and tennis and golf. But my business partner refused to even consider such a strategy. He was angry about iHanuman, which had been his girlfriend’s idea (she was a yoga instructor). We had burned through several million dollars looking for a “visionary” idea, and then in the end we had success with a fairly simple idea, selling instructional videos. If he had been willing to proceed with a boring success, we could have built an empire around that idea. Indeed, just a few years later, the crew behind Revolution Golf was to succeed as we should have, selling instructional videos about golf, and slowly building a whole set of related businesses around that (I think they now have bought 4 other sites relating to golf and sports?).

Many tech entrepreneurs starts companies at least in part because they consider themselves uniquely creative and insightful, and they want the whole world to see them as they see themselves. Often, the project they launch reveals an unexpected truth: their insights are proven false, what works in the end is something surprising.

What is the right way to handle unexpected success? In 1992, when Bo Peabody launched Tripod, he was thinking that the site would offer content aimed at college students. His idea failed. The company was saved because some of the programmers at the company had started a side project that allowed anyone to create their own web pages. This then became the future of the company. In his book, Lucky or Smart, Peabody says it is important to be smart enough to know when you are getting lucky. And then, you have to be willing to accept that luck. This takes humility. What’s needed in an entrepreneur is emotional resilience, the kind of strength that allows a person to show grace when their ideas have been proven wrong. One has to adapt to each surprise.

The entrepreneur will have to engage in new areas of activity which make them uncomfortable

Some of the things you need to do as an entrepreneur: sales, marketing, strategy, hiring, firing, accounting, law, taxes. Were these your specialities? Probably not. Starting a business forces people to engage in a lot of activities that they previously knew nothing about, and which they do not enjoy. But they are necessary activities.

I’ve spent most of 20 years writing software, so perhaps this is the pattern I’ve seen the most: the software developer who starts a company but who wants to continue to write software, because that is where they are the most comfortable. Yet they need to push themselves to do a lot else. Or else they fail.

Very few entrepreneurs start off as professional entrepreneurs. Most of them are something else first: a medical researcher, a Wall Street trader, a software engineer, a school teacher, a plumber, a restaurant server, an accountant. They are working in some specific role when they get their idea for starting a business. But they will need to learn new skills.

Some examples.

Rehearsals are important. I wish I could convince more entrepreneurs of this. Ted Talks, TV interviews, podcasts, MeetUps. I’ve seen entrepreneurs who are invited to speak in public, and they do badly. What should be a triumph becomes an embarrassment. Failure to rehearse is perhaps the most obvious form of self-sabotage.

When you become an entrepreneur, you will have to talk about your fledgling startup all the time. To investors, to customers, to your family, to your workers, to the public. You will be talking about it all the time. You need to do this well.

Speaking well in public is a skill that can be learned. Consider the professionals who spend their lives doing so. It doesn’t matter if your idea of charm is George Clooney or Will Smith or Paul Giamatti. Maybe you are fan of Ellen Page or Taraji Henson. Maybe you swoon over Gal Gadot. They all have an easy grace when speaking in public, because they have spent so many years doing so. They were not born that way.

On Friday I had lunch with an entrepreneur who struck me as unusually well-spoken. I said this to her and she made a self-deprecating joke about her awkwardness. But we discussed the issue for a few more minutes and she revealed that she sometimes used a video camera to record herself talking, and then she watched the video to see how she is coming across. And this is a fantastic technique.

If recording yourself makes you uncomfortable, then talk to a mirror. The important thing is to rehearse.

Mistakes I’ve seen entrepreneurs make when they don’t rehearse their presentation:

1.) they forget important points that need to be made

2.) they go off on unrelated tangents

3.) they attempt jokes that go badly

4.) they stutter

5.) they attempt to tell a story, but ruin it by telling the events out of order

6.) they indulge in mannerisms of which they are not conscious, but which are highly distracting to their audience

7.) they do not appear confident

I have a number of friends who are actors. They are also work with an organization that teaches business leaders how to speak in public. Among the skills they emphasize:

1.) how to hold space

2.) when to use silence

3.) when to use a conversational tone

4.) the importance of simple storytelling

5.) the distracting nature of body tics or mannerisms

One of my friends told me “The most important thing we do is video record them and then show them the video. It is absolutely brutal in terms of revealing body language.”

This kind of work used to be a specialty of the Eagles Flight Institute and though they have moved away from it, they are still a great source of different kinds of experiential learning for business leaders.

Another failure mode that I have seen is perfectionism regarding one aspect of the process of establishing the business. Twice I have seen entrepreneurs spend countless hours, over several months, polishing the pitch deck they use to woo investors. In both cases, the entrepreneurs fell into this pattern when things were going badly. They were running out of money and they were feeling a lot of stress. This kind of perfectionism is always a form of avoidance. They felt they could not control the technology, nor the tech team, nor the customers, but they could control their pitch deck, so they poured all of their energy into that. Colors, fonts, images: they would tweak it endlessly. The pitch deck did not necessarily get better, it simply changed. Meanwhile, the business got worse because other essential activities were being avoided. This kind of activity verges on depression, which is understandable when a person is under a lot of stress. It is crucial that the entrepreneur find some healthy way to deal with the stress: go running, find a therapist, take anti-depressants, have long talks with a trusted friend or minister — whatever it takes. If an entrepreneur is in a funk, either they snap out of it, or the business is doomed.

Different entrepreneurs will have different strengths and weaknesses. That is natural. The important thing is to recognize that some activities are absolutely essential. Either hire someone to do them, or learn how to do them. A good entrepreneur doesn’t avoid an activity just because it makes them uncomfortable, or because they find it boring.

Humility and Open-Mindedness

A thought about what it takes to succeed:

No one can accurately predict where the stock market will be in 2 years (otherwise they’d already be a trillionaire). For almost the same reason, no entrepreneur can fully know where their startup will be in 2 years: there are simply too many variables. It is important that innovators be humble about the limits of their knowledge. A fantastic insight in one area can carry you a long way, but it will have to adapt to the millions of small facts that will arise, almost daily, and shape the history of your insight as it passes from concept to reality. If you launch a startup, the odds are against you from the start, and you’re only hope of success is to remain open minded about what might work.

If your startup eventually succeeds, it will likely be for reasons you did not initially predict. You must proceed with the attitude of a scientist conducting an experiment, and when you get back the results, you must not argue with them, but rather, you must adjust your mental model of the world. When Sir Alexander Fleming saw that mold on some bread crumbs was keeping bacteria from growing in a petri dish, he said “Astounding! That mold must be producing some substance that kills bacteria! Perhaps that same substance can be used to kill bacteria in humans?” How many of us would be dead right now if he had rejected the evidence, and said simply “That’s impossible! Mold can’t hurt bacteria!” Over the previous 60 years, two other researchers had already noted the lack of bacteria in the presence of certain types of mold, yet they failed to perceive the importance of this observation. An entrepreneur would do well to emulate Fleming’s open mindedness.

Without open mindedness about the type of success you may encounter, your startup is doomed. And without humility about the limits of your knowledge, your startup is doomed.

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Comment here or on Hacker News

There exists a global community, a loosely knit consciousness of individuals that crosses boundaries of language and artistic disciplines.  It resides in both the online and physical space, its followers are dedicated, if not fervent.  The object and to some extent, philosophy that unites these adherents, is a computer system called the Commodore Amiga (https://en.wikipedia.org/wiki/Amiga).  So why does a machine made by a company that went bankrupt in 1994 have a cult like following?  Throughout this essay I will present to you, the reader, a study of qualitative data that has been collected at community events, social gatherings and conversations.  The resulting narrative is intended to illuminate the origins of the community, how it is structured and how members participate in it.  Game industry professionals, such as the person interviewed during the research for this paper, will attest to the properties, characteristics and creative application of the machine, and how this creativity plays a role in the sphere of their community.  I will examine the bonds of the society, to determine if the creative linage of the computer plays a role in community interactions.

The story of the Amiga and its maker, Commodore, is a long and complex tale, confusing it with a Tolstoy saga could be forgiven.  The purpose of this study is not to retell the origins of the Amiga computer or the demise of Commodore, but instead to look at the people that surround todays close knit global community.

Displaying the internal components
of the Commodore Amiga 3000T.

Home computing was undergoing a revolution during the mid 1980’s, computing power and connectivity, were on the rise while the entry cost into the hobby was dropping.  The market was awash with systems that were all jockeying for pole position.  One system that stood out from the rest was the Commodore Amiga, a system so unique and powerful for it’s time, it had Steve Jobs of Apple Computer nervous.  In 1985, the Apple Mac was limited to a grayscale display, where as the Amiga had color modes that went up to 4096 colors.

Membership is informal and very few User Groups (interacting users based in a similar geographic location) exist that require registration.  This differs from operations in the past.  Local User Groups in the 80’s and 90’s typically required member dues and were operational around the world, frequency of meetings varied from weekly to monthly.  In a much more limited scope, a number of these groups have either survived through the decades or reformed in new capacities, as can be seen at local meetings and their presence at yearly conferences.  The observed population segment that attends meetings and conferences is typically older, averaging from mid 30’s to late 50’s and mostly male.  With exception of smaller User Group meetings, most events that occur are on the scale of 200 – 300 people and cover a wide geographic area.  Conferences are quite affairs, the primary goal is to impart knowledge in a social setting.  The unmistakable hum of old CRT monitors serves as ambient white noise, occasionally punctured by a computer game melody and cheerful laughter.  Some machines are to be observed, from a distance, either they are rare and valuable or delicate and difficult to maintain.  However, these machines were made to be used, and standing alongside the interactive exhibits, their owners are typically ready and more than willing to answer any questions.

Interactive displays at
Amiga 30 conference.

The nature of the community and format of events enables individuals of all levels to participate how they see fit.  Meetings and larger shows are frequented by members imparting their historical knowledge about the computer, games, demo and BBS (Bulletin Board System) scene.  It’s quite likely some members didn’t make the conscious decision to become affiliated, instead their connection evolved out of their interest in computing, art or music.  For others, collaborating with people of complimentary skills sets, has produced new hardware designs that weren’t thought possible 30 years ago.  Active participation in forums and group discussion helps mold the direction of projects, further adding to the intellectual wealth of the community as a whole.

Spaceballs demo running on the Amiga 500,
a renowned demo of the early 90’s.

Software demos that are seen showcasing the capabilities of the Amiga at conferences or another type of event called “Demo Parties”, are decedents from a programing and art inspired sub-culture called the “Demoscene” (https://en.wikipedia.org/wiki/Demoscene).  The Amiga can be partially attributed to the creation of this related sub-culture.  Individuals with specialized talents in art, audio production and programming, who teamed together to form a group, are collectively known a Demogroup.  Together, the art and effects produced, push the computer to new limits.  Competition between groups was, and often still is, very competitive, with one group trying to out do another with a style of coding technique.  Today, is not uncommon at community events to find the the products of demo parties running on either original 30 year old hardware, or being emulated on a modern laptop.  Programmers are often coding “close to the metal”, that is, the languages they are using, have the minimal amount of interpretation by the computer that require the program to run, they are directly accessing physical parts of the machine.  The simplicity of the Amiga that enables this type of coding, is an incentive to younger generations – the “style” of the machine allows them to show off their skills.  Younger members are forming a solid base in primarily online forums, but also at physical demo parties.  The logical conclusion is that these individuals are one way the community will continue to grow, as the older generations inevitably pass on.

Commodore CDTV on display at Amiga 30.

Let us reference back to the primary assertion: the Amiga computer is a tool that binds creative individuals into a community.  To understand that statement, we must look at how the creative empowerment, enabled by the Amiga, gave rise to  careers in the game industry.  When questioned with: What was your favorite platform to develop on “Back in the day?”.  The response from an interviewed seasoned developer was: The Amiga home computer, a machine with a custom chipset for handling sound, video and I/O (input and output to the computer).  Combined with a low price point, the Amiga was the best choice for game development with it’s powerful graphic capabilities.

Secondly let us consider the response another question: When do you define the “Golden age” of video games? Answer: Probably 1987 to 1988, the C64 was in full swing and the 16bit machines (the Amiga) were just starting to take hold of the market.  Game development teams were growing in size in terms of numbers but they were still small enough for each member to feel the contribution of their efforts.

The underlying message that can be extrapolated: is creativity, an important function for this interviewee.  We can juxtaposition this inferred importance against observations at User Group meetings, to assume that the glue of the community, the reason these individuals are meeting, is the creative capabilities of the machine.  When we position the origins of the Amiga community – what it enabled users to do: coding, art and music, next to the observed creative output that is still being presented at meetings, the conclusion suggests, the forces of attraction to the community are not only a notion of nostalgia for a games machine, but the act of creativity itself.

Dave Haynie (right),
former Commodore engineer.

The achievements of the individuals that conceptualized the Amiga computer are highly recognized.  Engineers that worked for Commodore, such as Dave Haynie in the 1980’s and 1990’s along with hardware developers that continue development, command enthusiastic audiences at community events throughout the year.  It has been witnessed through observation at these events their willingness to meet and talk with not only small, intimate groups, but also large audiences.  It could be inferred that these actions not only help preserve the legacy of their work, but they are also functioning as ambassadors for the community.  Their efforts and openness introduce people to the platform who might not have been users during the machines commercial years, and help the community to thrive and expand.

Observations in the field have shown there is a specialized niche for newly produced hardware that typically enhances existing machines or replaces faulty components.  Vendors and technicians present at conferences perform technical services, many of whom do it for the love of the platform, and of course, a nominal fee.  Tucked away in corner locations, surrounded by machine carcasses, toolkits, soldering irons and empty caffeinated beverage cans, engineers can be found laboring on delicate hardware, the long lines of customers imply demand for their skill is high.  This observation of dedication, seen at events and in the online realm, reenforces the notion that individual’s embrace their technical contribution.  Their goals are not solely profit driven, and they are finding their niche in the community with this service.

Families play an important role at conventions, a large diversity of activities are available to entertain younger children that accompany parents.  Finding kids glued to a monitor playing a platform game is a common sight.  Introducing children not only continues the community and provides them with a glimpse of their parents youth, but has the added benefit of helping them understand the core concepts of computing, something which is often difficult to comprehend on modern systems.

To summarize the findings observed during community conferences, meetings, social media engagements and dialog from interviews, the catalysts for community engagement can be identified as:

• An outlet for creativity– art, music, animation.
• Intellectual challenge– programming, electrical engineering.
• Historical connection– familiarity and lengthy community interaction.
• Nostalgia– Games played in the past, introducing children to component of the parents youth.

With this information, would it be reasonable to speculate, the term “Amiga” not only describes a computer, but also a community who’s collaborations continue to find new ways of expressing art?  It’s a vision or non-tangible quality that cannot be described by the computers physical form of silicon and ABS plastic.  I would postulate that it is not an enormous stretch, to draw the conclusion, that the Amiga community isn’t centered around it’s physical attributes.  Instead, the community is defined as a collective consciousness of creativity and camaraderie, who’s inclusivity is not limited by an individuals own aptitude for any one creative or technical outlet.

Catskill, New York—the small Hudson River town where the American painter Thomas Cole lived and worked, from 1825 to 1847—is also home to the RamsHorn-Livingston Sanctuary, which contains four hundred and thirty acres of tidal marsh, upland forest, and fallow farmland, and is presently occupied by common loons, great blue and green herons, wood ducks, mallards, a pair of bald eagles, northern harrier and red-tailed hawks, ruffled grouse, merlin falcons, eastern screech and great horned owls, belted kingfishers, pileated woodpeckers, warblers, scarlet tanagers, blue-gray gnatcatchers, a tiny and nervous-looking thrush known as a veery, and various other species of birds whose names, I will admit, are perilously delightful to type. There is also a beaver.

This year marks the centennial of the Migratory Bird Treaty Act of 1918, a U.S. federal law that prohibits anyone from trying to “take, possess, import, export, transport, sell, purchase, barter, or offer for sale, purchase, or barter, any migratory bird, or the parts, nests, or eggs of such a bird except under the terms of a valid permit issued pursuant to Federal regulations.” In essence: don’t mess with birds! Bald eagles, being both the national bird and national animal of the United States, enjoy even more federal protections. If a person is caught pestering one—fussing with its nest, or otherwise interrupting its daily routine of swooping about and collecting fish—she can be fined a hundred thousand dollars, imprisoned for as long as a year, or both. (When the bald eagle was chosen to appear at the center of the Great Seal of the United States, in 1782, Benjamin Franklin was a little salty about the choice. In a letter to his daughter, Sally, in 1784, he derided its hunting methods, which include scavenging and snatching food from other birds. “For my own part I wish the Bald Eagle had not been chosen the Representative of our Country. He is a Bird of bad moral Character. He does not get his Living honestly,” Franklin wrote. He was more enamored of rattlesnakes. “She never begins an attack, nor, when once engaged, ever surrenders: She is therefore an emblem of magnanimity and true courage,” he wrote in 1775, in a letter to the Pennsylvania Journal.)

In November, the Republican congresswoman Liz Cheney, of Wyoming, introduced a piece of legislation that the Audubon Society quickly took to calling “the Bird-Killer Amendment.” It was added to HR 4239, or the SECURE American Energy Act, during a House Committee on Natural Resources meeting, and it would revise the Migratory Bird Treaty Act to better protect energy operators from having to prevent (or be held accountable for) bird deaths caused by oil-waste pits, transmission lines, gas flares, and more. “Our operators take multiple precautions to ensure migratory birds, as well as other wildlife, are not injured during operations, but if these precautions fail, the current language could impose criminal liability for the taking of the bird even though it’s accidental,” Cheney wrote in a press release. Her wording is sort of extraordinary, insofar as it circumvents evoking death directly—“the taking of the bird.” What does it mean? As David Yarnold, the president and C.E.O. of the Audubon Society, wrote in a recent editorial, “Birds are doing their best to find ways to live among people, but they don’t know that an oil pit isn’t a lake and they don’t know how to judge the speed of the blades on wind turbines.”

If Cheney gets what she wants—the bill, with her amendment, is awaiting a vote in the House—oil, gas, and turbine companies will no longer be held financially responsible for butchering avian populations. If this amendment had been added and passed in, say, 2009, B.P. wouldn’t have been legally compelled to spend millions of dollars restoring decimated bird habitats along the Gulf Coast after the Deepwater Horizon exploded and sank to the bottom of the sea.

This winter, I took to roaming the Catskill sanctuary every day after lunch. It’s situated less than a mile from the house where Martin Van Buren married his childhood sweetheart, in 1807, and where the real-life Uncle Sam lived, from 1817 until 1823. (In a terrifically American twist, a section of the house is now a rather intemperate-looking tiki bar.) The sanctuary operates via a partnership between the Audubon Society and Scenic Hudson, a local land-preservation and conservation group. On my walks, I saw dozens of cardinals and yellow-bellied sapsuckers, and the occasional pileated woodpecker, hammering away for beetles. Sometimes I came across little piles of fur and bone—gray remnants of whatever an owl had been pecking at the night before. When the sun hits the tidal marsh from the northwest, around 3 P.M., the cattails sway and glow, as if they’re made of spun gold.

I couldn’t find a bald eagle, though. I would pause excitedly whenever I encountered a splattering of white droppings on the trail, only to gaze longingly up at an unattended nest. Finally, someone told me that the eagles tend to spend their afternoons closer to the river, perching on, or around, the Rip Van Winkle Bridge. There had been abundant sightings farther south, too, between Croton and Verplanck Points—groups of five or more eagles, tossing a white perch back and forth. I didn’t want to bother them merely to raise my binoculars and behold one of their curved yellow beaks. In truth, adult bald eagles look a little mean. There’s something in their eyes that conveys furtive, panicked malice (“Though what bird in the best of circumstances does not look a little stricken?” the writer Lorrie Moore once wondered). When an eagle stretches its legs to snatch prey, it appears nearly bipedal, as if it could handily outpace a grown human in a footrace. Yet the call of an eagle is strangelydocile: a series of high, gasping squeaks. The sound reminds me of Mike Tyson, another renowned Catskill resident (he trained here, in the late eighties, at Cus D’Amato’s KO Boxing Gym, on Main Street). I found the disconnect between eagle squeak and eagle power intriguing, if suspicious.

Although bald eagles are not presently endangered, they are still protected by legislation distinct from the M.B.T.A., and that means that anyone who kills them or interferes with their lives will be punished, regardless of whether or not Cheney’s amendment is passed. (If you wish, you may contact your congressperson to protest the amendment by using this link.) But the M.B.T.A. has worked for a century, dutifully protecting birds against the encroachments of mankind. It’s hard, considering the Treaty’s future, not to feel the familiar ache of resignation: the way lobbyists coerce legislation into being, the way corporate interests are endlessly privileged, the way the difficult, patient work of conservation is often thwarted in favor of easier, faster money.

Eventually, I did encounter a bald eagle. I was standing on the banks of the Hudson, my snow boots sinking into February mud, watching a massive barge go lumbering by. I was thinking something like, Oh! A barge! Its wake was strong enough to displace a few sizable sheets of floating ice, which then rushed toward the shore, making waves. In a moment, I was up to my kneecaps in cold water. As I ran through my curse words and splashed about willy-nilly, I looked up, and there was the eagle: circling, huge, strident. I felt as if I should solemnly raise my hand to my breast and recite the Pledge of Allegiance. Then I thought of the humiliations that the present Administration has inflicted. All the old victories that have been overturned. Now they are coming for the birds.