ive METAL INJECTION LIVECAST #551 - Where Nickelback Shines with special guest Comedian Brian Posehn By feedproxy.google.com Published On :: Wed, 22 Jan 2020 03:00:18 +0000 We're so excited to have a huge guest on the show – big time comedian and noted metalhead, Brian Posehn,... The post METAL INJECTION LIVECAST #551 - Where Nickelback Shines with special guest Comedian Brian Posehn appeared first on Metal Injection. Full Article Metal Injection Livecast
ive METAL INJECTION LIVECAST #552 - Penis II Society By feedproxy.google.com Published On :: Wed, 29 Jan 2020 01:33:01 +0000 What's with all the good drummers dying? We kick things off discussing the sad news. Noa discussed locking herself out... The post METAL INJECTION LIVECAST #552 - Penis II Society appeared first on Metal Injection. Full Article Metal Injection Livecast
ive METAL INJECTION LIVECAST #553 - Full On Lip By feedproxy.google.com Published On :: Wed, 05 Feb 2020 02:03:04 +0000 What an eventful edition of the Metal Injection Livecast! We kick things off talking about the new Dave Mustaine memoir... The post METAL INJECTION LIVECAST #553 - Full On Lip appeared first on Metal Injection. Full Article Metal Injection Livecast
ive METAL INJECTION LIVECAST #554 - Rob's Nolita By feedproxy.google.com Published On :: Wed, 12 Feb 2020 01:22:42 +0000 We kick things off talking about the Rage Against the Machine reunion. We then discuss the summer touring season and... The post METAL INJECTION LIVECAST #554 - Rob's Nolita appeared first on Metal Injection. Full Article Metal Injection Livecast
ive The Chart Guide v4.0 - Interview & Giveaway By feedproxy.google.com Published On :: Fri, 08 Nov 2019 19:33:45 +0000 Michiel Dullaert, data visualization expert and trainer from the Netherlands, has updated his Chart Guide poster to version 4! A free PDF is available for download from his website, and introduces a new category, 19 new charts and 4 extra design tips. You can also purchase a full-size printed poster version.As the November 2019 Giveaway, I have a pair of Chart Guide posters, that will be shipped to one lucky winner. That way you get one for yourself, and one you can give to a friend or coworker.Register HERE by November 30, 2019 at 11:59pm CT, and the winner will be randomly chosen on December 1st!This poster shows 84 charts to choose from and includes 16 chart design tips to help you make the Perfect Chart. The poster is available as a big poster or you can download the PDF file for free. Let this ChartGuide poster help you choose and design your Perfect Chart.You can see his complete write-up about the new version HERE. I was able to ask Michiel a few interview questions about developing the posters:Cool Infographics: What’s your background and how did you get into visualizing data?Michiel Dullaert: Years ago I have been working in the boardgame and puzzle industry. Part of my work was discovering new boardgames and puzzles and introduce them to the market. I was working for two different companies, both at the time that a new product of theirs really changed the market. For the boardgame industry I worked for the company that introduced a new type of boardgame (the game of Catan) that made playing boardgames a popular hobby. After that, I worked for a company that created puzzle magazines at the time the Sudoku puzzles was introduced. And here the same happened again, a new type of puzzle that changed the way people would puzzle and talk about puzzles. Both were very nice jobs, with a lot of enthusiastic conversations with customers about new products.In both companies I was working in the product development. I always had a large personal interest in the data behind the products. So it felt logic to do more with data, and I changed careers. I started working for a large company as an analyst. And it was not long that I found out that my colleagues were not interested in my reports. Although the reports contained interesting information it was shown in large tables and busy charts. People seemed to be not interested and if the looked into the numbers, they did not seem to understand them. My work did not seem to matter. The contrast between my previous jobs and the work as an analyst could not have been bigger. At that time I decided I would try to find a way to make people as enthusiastic about data as they were about boardgames and Sudoku puzzles. The first step was reading books on the topic of data visualization. Because I was working in the business intelligence field, the most logic choice were the books of Stephen Few. I bought them all and a whole new world opened for me. When Few was in the Netherlands to give a course I felt very lucky I could join. The workshops inspired me to learn more on this topic. So I bought more books and the next year I joined a class of Alberto Caïro. This gave me multiple perspectives on the same topic. The things I learned were applied to my work, and I was getting more and more responses on my visualizations. People actually started to read and understand them. My manager asked me to explain my choices in visualizations to my colleagues, so they could learn from me. And then I discovered how great it is to teach about data visualisation. I met a couple of UX designers and they inspired me learn more about that topic and to get an UX certification. The knowledge I gained in learning UX helped me in developing my own perspective on good data visualization. And in my workshop I try to inspire others to create such. For these workshops I wanted an overview of charts. Although there were already some great overviews, none of them had the point of view I was teaching in class. So I decided to design my own. That’s how Chart.Guide started. Cool Infographics: Who is the Chart Guide poster intended for?Michiel Dullaert: The website and the posters are intended for everyone who makes charts. For me it does not matter if you are working as a data-journalist or a data scientist, a infographic designer, project manager or a financial analyst. As long as you need help or inspiration when making charts or tables, Chart.Guide can help you. Online in the form of the website and offline in the form of the poster. Because I want to inspire as many people as possible I made the PDF of the poster free to download. I know that the poster is used in business departments, newsrooms and in school classrooms.Cool Infographics: What was your design process for the poster?Michiel Dullaert: The main source for updates to the poster or website, is the conversations I have with people I teach or work with. If they have a need for certain chart types, or make design mistakes, I try to add that topic. DPG Chart Chooser The first poster edition (picture DPG Chart Chooser) was just a collection of charts I created for my students. For each chart a few words on when to use the chart and, more important, it gave advice on what charts were not recommended. On the second edition (the first under the Chart.Guide brand) I added chart design tips. The reason, I saw people choose a good chart but then mess up the design. Last year, I got questions about maps, so I decided to add them on poster edition 4. Rearranging the layout of the Chart Guide The design process starts with insight I get from conversations I am having. Next step is cutting the old poster and rearranging everything. (see picture ChartGuide rearrange) now, will lead to more insights on the poster in the future. Although it make take some time to transform everything to the screen or paper. I still need to find some time to explain on the website why some charts are “not recommended”. Cool Infographics: You asked your followers to help choose the design of the new poster. How did that go?Michiel Dullaert: The poster is made to help people. So it seems to be logic to give them a role in the design process. As a UX designer I like to test my designs before releasing them. Most of these tests are done in class, because I like to observe the users in how they use the new design. The online voting was suggestion of a student. It did give me a lot of useful feedback. Especially when people wrote a lot of text explaining their choice. For future editions I will do the same.Cool Infographics: How can people follow you for updates?Michiel Dullaert: People who have downloaded the PDF will get an email when a new poster is available, or when something interesting is added to the website. For this and more chart related inspiration, they can follow me on Twitter: @Chart_Guide or on facebook: /ChartGuide1.This helpful reference guide is one of over 25 FREE data visualization guides I maintain links to in the Cool Infographics Tools pages. See them all on the DataViz Reference Guides page, and let me know if I’m missing any. Full Article
ive ‘Utterly Terrifying’: Study Affirms Feedback Loop Fears as Surging Antarctica Ice Loss Tripled in Last Five Years By feedproxy.google.com Published On :: Fri, 15 Jun 2018 00:49:16 +0000 By Jessica Corbett Common Dreams “The most robust study of the ice mass balance of Antarctica to date,” scientists say, “now puts Antarctica in the frame as one of the largest contributors to sea-level rise.” Scientists are expressing alarm over … Continue reading → Full Article Climate & Climate Change Climate Change ET Antarctic Antarctic ice sheet Antartic ice loss sea level rise
ive What is cognitive load and why does it matter in web and interface design? By feedproxy.google.com Published On :: Thu, 27 Jun 2019 15:25:28 +0000 Successful design manages cognitive load. Cognitive load is a technical term for “mental effort,” more specifically it’s the total amount of mental effort required for a given task. Completing any task requires some level of mental effort. This includes learning new information, analyzing stimuli, and working with short and long-term memory. Mental energy which has […] The post What is cognitive load and why does it matter in web and interface design? appeared first on Psychology of Web Design | 3.7 Blog. Full Article Psychology of Design User Experience Web Design
ive 10 Design Principles to Reduce Cognitive Load By feedproxy.google.com Published On :: Thu, 25 Jul 2019 14:52:24 +0000 If you’re not familiar with cognitive load and how it impacts interface design, it’s worth reviewing our previous blog post. If you’re already convinced cognitive load is important, the next step is addressing it. Reducing cognitive load is accomplished by reducing or offloading mental effort (which are similar but different concepts.) Reducing mental effort is […] The post 10 Design Principles to Reduce Cognitive Load appeared first on Psychology of Web Design | 3.7 Blog. Full Article Psychology of Design User Experience
ive Modern Website Deliverables By feedproxy.google.com Published On :: Mon, 18 Nov 2019 21:11:58 +0000 You’re hiring a web designer or providing web design services, what’s included in a normal project? In other words, what are the deliverables, and the use of a membership website builder could be essential for this. Let’s start by defining what a deliverable is. Wikipedia defines a deliverable as: …a tangible or intangible good or […] The post Modern Website Deliverables appeared first on Psychology of Web Design | 3.7 Blog. Full Article Business Running an Agency Web Design
ive 12 Best GoDaddy Alternatives for Domain & Web Hosting (2020) By www.isitwp.com Published On :: Fri, 01 May 2020 05:31:34 +0000 Are you looking for the best GoDaddy alternative for domain registration and web hosting? Without a doubt, Godaddy is one of the most popular names when it comes to registering domain names and hosting your business online. Over the last 22 years, GoDaddy has managed to establish a stronghold in the market. In this article, […] The post 12 Best GoDaddy Alternatives for Domain & Web Hosting (2020) appeared first on IsItWP - Free WordPress Theme Detector. Full Article Resources domain registration godaddy alternatives web hosting
ive Advice for Caregivers: Walking in the Shoes of a Loved One with TBI and/or PTSD By feedproxy.google.com Published On :: Mon, 06 Jan 2014 00:00:00 EST Adam offers advice to caregivers of a loved one with TBI and/or PTSD — from simply trying to see how that person's life has changed to helping him get involved in confidence-boosting activities. Full Article
ive Troops to receive Purple Hearts for injuries during Iranian missile barrage on al-Asad airbase in Iraq By feedproxy.google.com Published On :: Wednesday, April 29, 2020 - 1:50pm There will be Purple Hearts awarded to troops injured during the Jan. 8 Iranian missile barrage on the al-Asad airbase in Iraq, a defense official told Military Times. Full Article
ive The Biodiversity Photography Contest By www.photocompete.com Published On :: Wed, 06 May 2020 09:53:21 +0000 The Biodiversity Photography Contest has as main objective to promote the theme of biological natural heritage, namely the natural regions, the ecosystems, the habitats and [...] The post The Biodiversity Photography Contest appeared first on Photocompete. Full Article Animals Contests Current Exhibition International Nature
ive Ramit Sethi: Money + Other Ways to Live Rich By feedproxy.google.com Published On :: Wed, 31 Jul 2019 13:15:09 +0000 Ditch the idea of yourself as a starving artist. Throw away the notion that you’re doomed to be another poor creative soul. My long time pal Ramit Sethi is back on the show to remind us we need to get back on track to building and living a rich life. And believe me, that doesn’t have to mean cutting back the lattes. Ramit has been on the show a few times, but if you haven’t caught up yet, let me fill you in. Ramit Sethi is the author of the NYT bestseller “I Will Teach You To Be Rich” and writes for over 500,000 monthly readers on his website, iwillteachyoutoberich.com. It’s one of my favorite go-to finance resources covering psychology, personal finance, careers, and entrepreneurship. No one has single-handedly given me better insight into the business side of art, than Ramit. Ramit has updated & expanded 2nd edition of his book and joined me for a LIVE studio conversation on money confessions. In this episode we get into: A rich life isn’t only about save money, it’s about defining & prioritizing the things you love the most. It’s one thing to manage our own personal finances but navigating that with […] The post Ramit Sethi: Money + Other Ways to Live Rich appeared first on Chase Jarvis Photography. Full Article chasejarvisLIVE Podcast author finance money negotiating personal finance ramit sethi
ive A [big] new challenge—the story behind the Creative Calling book cover By feedproxy.google.com Published On :: Mon, 12 Aug 2019 13:15:00 +0000 When it was time to think about the cover – the whole design package – for my NEW BOOK, Creative Calling, I knew I wanted it to be something different. After all…see if you follow me here… it’s just wrong to make a book about creativity with just any old trend, cliche book cover. Instead, the package needed to embody the ideas within. So when we approached this design challenge of a hard bound book – it had to be meaningful, beautiful, AND stand out in a sea of other books on the shelf. No small task… And consider this: you know that this isn’t just a nice story about the book cover. This is a metaphor for any creative challenge. Like every episode of podcast is full of practical advice….this is the real life story of ups and downs on this process…on how we struggled to overcame the challenge front of us… with costs, design options, time, publisher feedback, and other real-life constraints. In short of EVERY CREATIVE PROCESS. I’ve included 2 live-recorded phone calls with the designers on the project, Lou and Vasco, so you get their take on the creation process, challenges, the concepts behind what we set out to […] The post A [big] new challenge—the story behind the Creative Calling book cover appeared first on Chase Jarvis Photography. Full Article chasejarvisLIVE Podcast bts Creative Calling
ive Intuition, Creative Freedom & Doing What You Love with Chris Ballew By feedproxy.google.com Published On :: Wed, 14 Aug 2019 13:15:04 +0000 Today’s episode is going to rock your world … pun fully intended because today’s guest is an actual rock star. You may remember a band called Presidents of the United States of America. They took the world by storm in 1995 with their self titled album, Presidents of the United States of America playing songs like Lump and Peaches. Yes, that’s right. My guest today is frontman Chris Ballew. Chris and I have been friends for years, including collaborating on a music video together and at least one live performance (gotta listen to find out ;). Of course we get into his musical journey, a meteoric rise to success, and then realizing something was missing. We take some deep dives into Chris’ creative process, including his method for capturing his small bits and later using those to write new works, including his new project Casper Babypants. In this episode: Consider what kind of artist you are and how you relate to other artists. For years Chris played in bands, but what he learned about himself is his work is actually solo. Don’t censor yourself while you’re creating. Get it out, no matter how crazy or ridiculous or unusual and then […] The post Intuition, Creative Freedom & Doing What You Love with Chris Ballew appeared first on Chase Jarvis Photography. Full Article chasejarvisLIVE Podcast art Caspar Babypants chris ballew creative process Inspiration music
ive Design Your Life with Creative Calling + Debbie Millman By feedproxy.google.com Published On :: Wed, 04 Dec 2019 14:15:31 +0000 Debbie Millman is one of my dear friends, a powerhouse creative and someone who inspires me every day. When I was developing my online companion class to the Creative Calling book, of course I had to ask Debbie to join me on stage for a conversation around designing our life with intention. Debbie’s insight is pure gold. AND – this is just one of the segments from the class. If you already have my book, you can access the entire class for free. All you need to do is visit www.creativelive.com/creativecalling and sign up there. Enjoy! FOLLOW DEBBIE: instagram | twitter | website Listen to the Podcast Subscribe This podcast is brought to you by CreativeLive. CreativeLive is the world’s largest hub for online creative education in photo/video, art/design, music/audio, craft/maker, money/life and the ability to make a living in any of those disciplines. They are high quality, highly curated classes taught by the world’s top experts — Pulitzer, Oscar, Grammy Award winners, New York Times best selling authors and the best entrepreneurs of our times. The post Design Your Life with Creative Calling + Debbie Millman appeared first on Chase Jarvis Photography. Full Article chasejarvisLIVE Podcast confidence Creative Calling creativeLIVE creativity Debbie Millman design fear
ive Markdown Comes Alive! Part 1, Basic Editor By feedproxy.google.com Published On :: Wed, 26 Feb 2020 08:00:00 -0500 In my last post, I covered what LiveView is at a high level. In this series, we’re going to dive deeper and implement a LiveView powered Markdown editor called Frampton. This series assumes you have some familiarity with Phoenix and Elixir, including having them set up locally. Check out Elizabeth’s three-part series on getting started with Phoenix for a refresher. This series has a companion repository published on GitHub. Get started by cloning it down and switching to the starter branch. You can see the completed application on master. Our goal today is to make a Markdown editor, which allows a user to enter Markdown text on a page and see it rendered as HTML next to it in real-time. We’ll make use of LiveView for the interaction and the Earmark package for rendering Markdown. The starter branch provides some styles and installs LiveView. Rendering Markdown Let’s set aside the LiveView portion and start with our data structures and the functions that operate on them. To begin, a Post will have a body, which holds the rendered HTML string, and title. A string of markdown can be turned into HTML by calling Post.render(post, markdown). I think that just about covers it! First, let’s define our struct in lib/frampton/post.ex: defmodule Frampton.Post do defstruct body: "", title: "" def render(%__MODULE{} = post, markdown) do # Fill me in! end end Now the failing test (in test/frampton/post_test.exs): describe "render/2" do test "returns our post with the body set" do markdown = "# Hello world!" assert Post.render(%Post{}, markdown) == {:ok, %Post{body: "<h1>Hello World</h1> "}} end end Our render method will just be a wrapper around Earmark.as_html!/2 that puts the result into the body of the post. Add {:earmark, "~> 1.4.3"} to your deps in mix.exs, run mix deps.get and fill out render function: def render(%__MODULE{} = post, markdown) do html = Earmark.as_html!(markdown) {:ok, Map.put(post, :body, html)} end Our test should now pass, and we can render posts! [Note: we’re using the as_html! method, which prints error messages instead of passing them back to the user. A smarter version of this would handle any errors and show them to the user. I leave that as an exercise for the reader…] Time to play around with this in an IEx prompt (run iex -S mix in your terminal): iex(1)> alias Frampton.Post Frampton.Post iex(2)> post = %Post{} %Frampton.Post{body: "", title: ""} iex(3)> {:ok, updated_post} = Post.render(post, "# Hello world!") {:ok, %Frampton.Post{body: "<h1>Hello world!</h1> ", title: ""}} iex(4)> updated_post %Frampton.Post{body: "<h1>Hello world!</h1> ", title: ""} Great! That’s exactly what we’d expect. You can find the final code for this in the render_post branch. LiveView Editor Now for the fun part: Editing this live! First, we’ll need a route for the editor to live at: /editor sounds good to me. LiveViews can be rendered from a controller, or directly in the router. We don’t have any initial state, so let's go straight from a router. First, let's put up a minimal test. In test/frampton_web/live/editor_live_test.exs: defmodule FramptonWeb.EditorLiveTest do use FramptonWeb.ConnCase import Phoenix.LiveViewTest test "the editor renders" do conn = get(build_conn(), "/editor") assert html_response(conn, 200) =~ "data-test="editor"" end end This test doesn’t do much yet, but notice that it isn’t live view specific. Our first render is just the same as any other controller test we’d write. The page’s content is there right from the beginning, without the need to parse JavaScript or make API calls back to the server. Nice. To make that test pass, add a route to lib/frampton_web/router.ex. First, we import the LiveView code, then we render our Editor: import Phoenix.LiveView.Router # … Code skipped ... # Inside of `scope "/"`: live "/editor", EditorLive Now place a minimal EditorLive module, in lib/frampton_web/live/editor_live.ex: defmodule FramptonWeb.EditorLive do use Phoenix.LiveView def render(assigns) do ~L""" <div data-test=”editor”> <h1>Hello world!</h1> </div> """ end def mount(_params, _session, socket) do {:ok, socket} end end And we have a passing test suite! The ~L sigil designates that LiveView should track changes to the content inside. We could keep all of our markup in this render/1 method, but let’s break it out into its own template for demonstration purposes. Move the contents of render into lib/frampton_web/templates/editor/show.html.leex, and replace EditorLive.render/1 with this one liner: def render(assigns), do: FramptonWeb.EditorView.render("show.html", assigns). And finally, make an EditorView module in lib/frampton_web/views/editor_view.ex: defmodule FramptonWeb.EditorView do use FramptonWeb, :view import Phoenix.LiveView end Our test should now be passing, and we’ve got a nicely separated out template, view and “live” server. We can keep markup in the template, helper functions in the view, and reactive code on the server. Now let’s move forward to actually render some posts! Handling User Input We’ve got four tasks to accomplish before we are done: Take markdown input from the textarea Send that input to the LiveServer Turn that raw markdown into HTML Return the rendered HTML to the page. Event binding To start with, we need to annotate our textarea with an event binding. This tells the liveview.js framework to forward DOM events to the server, using our liveview channel. Open up lib/frampton_web/templates/editor/show.html.leex and annotate our textarea: <textarea phx-keyup="render_post"></textarea> This names the event (render_post) and sends it on each keyup. Let’s crack open our web inspector and look at the web socket traffic. Using Chrome, open the developer tools, navigate to the network tab and click WS. In development you’ll see two socket connections: one is Phoenix LiveReload, which polls your filesystem and reloads pages appropriately. The second one is our LiveView connection. If you let it sit for a while, you’ll see that it's emitting a “heartbeat” call. If your server is running, you’ll see that it responds with an “ok” message. This lets LiveView clients know when they've lost connection to the server and respond appropriately. Now, type some text and watch as it sends down each keystroke. However, you’ll also notice that the server responds with a “phx_error” message and wipes out our entered text. That's because our server doesn’t know how to handle the event yet and is throwing an error. Let's fix that next. Event handling We’ll catch the event in our EditorLive module. The LiveView behavior defines a handle_event/3 callback that we need to implement. Open up lib/frampton_web/live/editor_live.ex and key in a basic implementation that lets us catch events: def handle_event("render_post", params, socket) do IO.inspect(params) {:noreply, socket} end The first argument is the name we gave to our event in the template, the second is the data from that event, and finally the socket we’re currently talking through. Give it a try, typing in a few characters. Look at your running server and you should see a stream of events that look something like this: There’s our keystrokes! Next, let’s pull out that value and use it to render HTML. Rendering Markdown Lets adjust our handle_event to pattern match out the value of the textarea: def handle_event("render_post", %{"value" => raw}, socket) do Now that we’ve got the raw markdown string, turning it into HTML is easy thanks to the work we did earlier in our Post module. Fill out the body of the function like this: {:ok, post} = Post.render(%Post{}, raw) IO.inspect(post) If you type into the textarea you should see output that looks something like this: Perfect! Lastly, it’s time to send that rendered html back to the page. Returning HTML to the page In a LiveView template, we can identify bits of dynamic data that will change over time. When they change, LiveView will compare what has changed and send over a diff. In our case, the dynamic content is the post body. Open up show.html.leex again and modify it like so: <div class="rendered-output"> <%= @post.body %> </div> Refresh the page and see: Whoops! The @post variable will only be available after we put it into the socket’s assigns. Let’s initialize it with a blank post. Open editor_live.ex and modify our mount/3 function: def mount(_params, _session, socket) do post = %Post{} {:ok, assign(socket, post: post)} end In the future, we could retrieve this from some kind of storage, but for now, let's just create a new one each time the page refreshes. Finally, we need to update the Post struct with user input. Update our event handler like this: def handle_event("render_post", %{"value" => raw}, %{assigns: %{post: post}} = socket) do {:ok, post} = Post.render(post, raw) {:noreply, assign(socket, post: post) end Let's load up http://localhost:4000/editor and see it in action. Nope, that's not quite right! Phoenix won’t render this as HTML because it’s unsafe user input. We can get around this (very good and useful) security feature by wrapping our content in a raw/1 call. We don’t have a database and user processes are isolated from each other by Elixir. The worst thing a malicious user could do would be crash their own session, which doesn’t bother me one bit. Check the edit_posts branch for the final version. Conclusion That’s a good place to stop for today. We’ve accomplished a lot! We’ve got a dynamically rendering editor that takes user input, processes it and updates the page. And we haven’t written any JavaScript, which means we don’t have to maintain or update any JavaScript. Our server code is built on the rock-solid foundation of the BEAM virtual machine, giving us a great deal of confidence in its reliability and resilience. In the next post, we’ll tackle making a shared editor, allowing multiple users to edit the same post. This project will highlight Elixir’s concurrency capabilities and demonstrate how LiveView builds on them to enable some incredible user experiences. Full Article Code Back-end Engineering
ive TrailBuddy: Using AI to Create a Predictive Trail Conditions App By feedproxy.google.com Published On :: Thu, 19 Mar 2020 08:00:00 -0400 Viget is full of outdoor enthusiasts and, of course, technologists. For this year's Pointless Weekend, we brought these passions together to build TrailBuddy. This app aims to solve that eternal question: Is my favorite trail dry so I can go hike/run/ride? While getting muddy might rekindle fond childhood memories for some, exposing your gear to the elements isn’t great – it’s bad for your equipment and can cause long-term, and potentially expensive, damage to the trail. There are some trail apps out there but we wanted one that would focus on current conditions. Currently, our favorites trail apps, like mtbproject.com, trailrunproject.com, and hikingproject.com -- all owned by REI, rely on user-reported conditions. While this can be effective, the reports are frequently unreliable, as condition reports can become outdated in just a few days. Our goal was to solve this problem by building an app that brought together location, soil type, and weather history data to create on-demand condition predictions for any trail in the US. We built an initial version of TrailBuddy by tapping into several readily-available APIs, then running the combined data through a machine learning algorithm. (Oh, and also by bringing together a bunch of smart and motivated people and combining them with pizza and some of the magic that is our Pointless Weekends. We'll share the other Pointless Project, Scurry, with you soon.) Learn More We're hiring Front-End Developers in our Boulder, Chattanooga, Durham, Falls Church and Remote (U.S. Only) offices. Learn more and introduce yourself. The quest for data. We knew from the start this app would require data from a number of sources. As previously mentioned, we used REI’s APIs (i.e. https://www.hikingproject.com/data) as the source for basic trail information. We used the trails’ latitude and longitude coordinates as well as its elevation to query weather and soil type. We also found data points such as a trail’s total distance to be relevant to our app users and decided to include that on the front-end, too. Since we wanted to go beyond relying solely on user-reported metrics, which is how REI’s current MTB project works, we came up with a list of factors that could affect the trail for that day. First on that list was weather. We not only considered the impacts of the current forecast, but we also looked at the previous day’s forecast. For example, it’s safe to assume that if it’s currently raining or had been raining over the last several days, it would likely lead to muddy and unfavorable conditions for that trail. We utilized the DarkSky API (https://darksky.net/dev) to get the weather forecasts for that day, as well as the records for previous days. This included expected information, like temperature and precipitation chance. It also included some interesting data points that we realized may be factors, like precipitation intensity, cloud cover, and UV index. But weather alone can’t predict how muddy or dry a trail will be. To determine that for sure, we also wanted to use soil data to help predict how well a trail’s unique soil composition recovers after precipitation. Similar amounts of rain on trails of very different soil types could lead to vastly different trail conditions. A more clay-based soil would hold water much longer, and therefore be much more unfavorable, than loamy soil. Finding a reliable source for soil type and soil drainage proved incredibly difficult. After many hours, we finally found a source through the USDA that we could use. As a side note—the USDA keeps track of lots of data points on soil information that’s actually pretty interesting! We can’t say we’re soil experts but, we felt like we got pretty close. We used Whimsical to build our initial wireframes. Putting our design hats on. From the very first pitch for this app, TrailBuddy’s main differentiator to peer trail resources is its ability to surface real-time information, reliably, and simply. For as complicated as the technology needed to collect and interpret information, the front-end app design needed to be clean and unencumbered. We thought about how users would naturally look for information when setting out to find a trail and what factors they’d think about when doing so. We posed questions like: How easy or difficult of a trail are they looking for?How long is this trail?What does the trail look like?How far away is the trail in relation to my location?For what activity am I needing a trail for? Is this a trail I’d want to come back to in the future? By putting ourselves in our users’ shoes we quickly identified key features TrailBuddy needed to have to be relevant and useful. First, we needed filtering, so users could filter between difficulty and distance to narrow down their results to fit the activity level. Next, we needed a way to look up trails by activity type—mountain biking, hiking, and running are all types of activities REI’s MTB API tracks already so those made sense as a starting point. And lastly, we needed a way for the app to find trails based on your location; or at the very least the ability to find a trail within a certain distance of your current location. We used Figma to design, prototype, and gather feedback on TrailBuddy. Using machine learning to predict trail conditions. As stated earlier, none of us are actual soil or data scientists. So, in order to achieve the real-time conditions reporting TrailBuddy promised, we’d decided to leverage machine learning to make predictions for us. Digging into the utility of machine learning was a first for all of us on this team. Luckily, there was an excellent tutorial that laid out the basics of building an ML model in Python. Provided a CSV file with inputs in the left columns, and the desired output on the right, the script we generated was able to test out multiple different model strategies, and output the effectiveness of each in predicting results, shown below. We assembled all of the historical weather and soil data we could find for a given latitude/longitude coordinate, compiled a 1000 * 100 sized CSV, ran it through the Python evaluator, and found that the CART and SVM models consistently outranked the others in terms of predicting trail status. In other words, we found a working model for which to run our data through and get (hopefully) reliable predictions from. The next step was to figure out which data fields were actually critical in predicting the trail status. The more we could refine our data set, the faster and smarter our predictive model could become. We pulled in some Ruby code to take the original (and quite massive) CSV, and output smaller versions to test with. Now again, we’re no data scientists here but, we were able to cull out a good majority of the data and still get a model that performed at 95% accuracy. With our trained model in hand, we could serialize that to into a model.pkl file (pkl stands for “pickle”, as in we’ve “pickled” the model), move that file into our Rails app along with it a python script to deserialize it, pass in a dynamic set of data, and generate real-time predictions. At the end of the day, our model has a propensity to predict fantastic trail conditions (about 99% of the time in fact…). Just one of those optimistic machine learning models we guess. Where we go from here. It was clear that after two days, our team still wanted to do more. As a first refinement, we’d love to work more with our data set and ML model. Something that was quite surprising during the weekend was that we found we could remove all but two days worth of weather data, and all of the soil data we worked so hard to dig up, and still hit 95% accuracy. Which … doesn’t make a ton of sense. Perhaps the data we chose to predict trail conditions just isn’t a great empirical predictor of trail status. While these are questions too big to solve in just a single weekend, we'd love to spend more time digging into this in a future iteration. Full Article News & Culture
ive Five Aspects of a Successful Blog Post By feedproxy.google.com Published On :: Tue, 06 Feb 2018 14:34:13 +0000 It’s 2018, and traditional marketing concept has shifted. We often hear that content marketing is taking the top and is the future of marketing. While content marketing doesn’t only mean blogging, blog posts on a product, service or about your business, should be a big part of your content marketing strategy. There are vast amounts … Five Aspects of a Successful Blog Post Read More » Full Article Reference
ive Why Collaborative Coding Is The Ultimate Career Hack By feedproxy.google.com Published On :: Fri, 24 Apr 2020 10:30:00 +0000 Taking your first steps in programming is like picking up a foreign language. At first, the syntax makes no sense, the vocabulary is unfamiliar, and everything looks and sounds unintelligible. If you’re anything like me when I started, fluency feels impossible. I promise it isn’t. When I began coding, the learning curve hit me — hard. I spent ten months teaching myself the basics while trying to stave off feelings of self-doubt that I now recognize as imposter syndrome. Full Article
ive Mirage JS Deep Dive: Understanding Mirage JS Models And Associations (Part 1) By feedproxy.google.com Published On :: Thu, 30 Apr 2020 09:30:00 +0000 Mirage JS is helping simplify modern front-end development by providing the ability for front-end engineers to craft applications without relying on an actual back-end service. In this article, I’ll be taking a framework-agnostic approach to show you Mirage JS models and associations. If you haven’t heard of Mirage JS, you can read my previous article in which I introduce it and also integrate it with the progressive framework Vue.js. Full Article
ive Meet SmashingConf Live: Our New Interactive Online Conference By feedproxy.google.com Published On :: Tue, 05 May 2020 12:50:00 +0000 In these strange times when everything is connected, it’s too easy to feel lonely and detached. Yes, everybody is just one message away, but there is always something in the way — deadlines to meet, Slack messages to reply, or urgent PRs to review. Connections need time and space to grow, just like learning, and conferences are a great way to find that time and that space. In fact, with SmashingConfs, we’ve always been trying to create such friendly and inclusive spaces. Full Article
ive Prolific, the (Much Better) Mechnical Turk Alternative By eagereyes.org Published On :: Tue, 05 Nov 2019 07:17:08 +0000 Prolific is a crowd-sourcing platform for running studies. In contrast to the widely-used Mechanical Turk, it’s specific to studies, has a much better interface, pricing that’s fair to participants, and useful filters to find the right people for your study. Amazon's Mechanical Turk is used for many empirical studies published in the visualization literature, but […] Full Article Blog 2019
ive Non-associative Frobenius algebras for simply laced Chevalley groups. (arXiv:2005.02625v1 [math.RA] CROSS LISTED) By arxiv.org Published On :: We provide an explicit construction for a class of commutative, non-associative algebras for each of the simple Chevalley groups of simply laced type. Moreover, we equip these algebras with an associating bilinear form, which turns them into Frobenius algebras. This class includes a 3876-dimensional algebra on which the Chevalley group of type E8 acts by automorphisms. We also prove that these algebras admit the structure of (axial) decomposition algebras. Full Article
ive Convergent normal forms for five dimensional totally nondegenerate CR manifolds in C^4. (arXiv:2004.11251v2 [math.CV] UPDATED) By arxiv.org Published On :: Applying the equivariant moving frames method, we construct convergent normal forms for real-analytic 5-dimensional totally nondegenerate CR submanifolds of C^4. These CR manifolds are divided into several biholomorphically inequivalent subclasses, each of which has its own complete normal form. Moreover it is shown that, biholomorphically, Beloshapka's cubic model is the unique member of this class with the maximum possible dimension seven of the corresponding algebra of infinitesimal CR automorphisms. Our results are also useful in the study of biholomorphic equivalence problem between CR manifolds, in question. Full Article
ive The $kappa$-Newtonian and $kappa$-Carrollian algebras and their noncommutative spacetimes. (arXiv:2003.03921v2 [hep-th] UPDATED) By arxiv.org Published On :: We derive the non-relativistic $c oinfty$ and ultra-relativistic $c o 0$ limits of the $kappa$-deformed symmetries and corresponding spacetime in (3+1) dimensions, with and without a cosmological constant. We apply the theory of Lie bialgebra contractions to the Poisson version of the $kappa$-(A)dS quantum algebra, and quantize the resulting contracted Poisson-Hopf algebras, thus giving rise to the $kappa$-deformation of the Newtonian (Newton-Hooke and Galilei) and Carrollian (Para-Poincar'e, Para-Euclidean and Carroll) quantum symmetries, including their deformed quadratic Casimir operators. The corresponding $kappa$-Newtonian and $kappa$-Carrollian noncommutative spacetimes are also obtained as the non-relativistic and ultra-relativistic limits of the $kappa$-(A)dS noncommutative spacetime. These constructions allow us to analyze the non-trivial interplay between the quantum deformation parameter $kappa$, the curvature parameter $eta$ and the speed of light parameter $c$. Full Article
ive Data-driven parameterizations of suboptimal LQR and H2 controllers. (arXiv:1912.07671v2 [math.OC] UPDATED) By arxiv.org Published On :: In this paper we design suboptimal control laws for an unknown linear system on the basis of measured data. We focus on the suboptimal linear quadratic regulator problem and the suboptimal H2 control problem. For both problems, we establish conditions under which a given data set contains sufficient information for controller design. We follow up by providing a data-driven parameterization of all suboptimal controllers. We will illustrate our results by numerical simulations, which will reveal an interesting trade-off between the number of collected data samples and the achieved controller performance. Full Article
ive Universal Covers of Finite Groups. (arXiv:1910.11453v2 [math.GR] UPDATED) By arxiv.org Published On :: Motivated by quotient algorithms, such as the well-known $p$-quotient or solvable quotient algorithms, we describe how to compute extensions $ ilde H$ of a finite group $H$ by a direct sum of isomorphic simple $mathbb{Z}_p H$-modules such that $H$ and $ ilde H$ have the same number of generators. Similar to other quotient algorithms, our description will be via a suitable covering group of $H$. Defining this covering group requires a study of the representation module, as introduced by Gasch"utz in 1954. Our investigation involves so-called Fox derivatives (coming from free differential calculus) and, as a by-product, we prove that these can be naturally described via a wreath product construction. An important application of our results is that they can be used to compute, for a given epimorphism $G o H$ and simple $mathbb{Z}_p H$-module $V$, the largest quotient of $G$ that maps onto $H$ with kernel isomorphic to a direct sum of copies of $V$. For this we also provide a description of how to compute second cohomology groups for the (not necessarily solvable) group $H$, assuming a confluent rewriting system for $H$. To represent the corresponding group extensions on the computer, we introduce a new hybrid format that combines this rewriting system with the polycyclic presentation of the module. Full Article
ive Compact manifolds of dimension $ngeq 12$ with positive isotropic curvature. (arXiv:1909.12265v4 [math.DG] UPDATED) By arxiv.org Published On :: We prove the following result: Let $(M,g_0)$ be a compact manifold of dimension $ngeq 12$ with positive isotropic curvature. Then $M$ is diffeomorphic to a spherical space form, or a compact quotient manifold of $mathbb{S}^{n-1} imes mathbb{R}$ by diffeomorphisms, or a connected sum of a finite number of such manifolds. This extends a recent work of Brendle, and implies a conjecture of Schoen in dimensions $ngeq 12$. The proof uses Ricci flow with surgery on compact orbifolds with isolated singularities. Full Article
ive Gabriel-Roiter measure, representation dimension and rejective chains. (arXiv:1903.05555v2 [math.RT] UPDATED) By arxiv.org Published On :: The Gabriel-Roiter measure is used to give an alternative proof of the finiteness of the representation dimension for Artin algebras, a result established by Iyama in 2002. The concept of Gabriel-Roiter measure can be extended to abelian length categories and every such category has multiple Gabriel-Roiter measures. Using this notion, we prove the following broader statement: given any object $X$ and any Gabriel-Roiter measure $mu$ in an abelian length category $mathcal{A}$, there exists an object $X'$ which depends on $X$ and $mu$, such that $Gamma = operatorname{End}_{mathcal{A}}(X oplus X')$ has finite global dimension. Analogously to Iyama's original results, our construction yields quasihereditary rings and fits into the theory of rejective chains. Full Article
ive On the Total Curvature and Betti Numbers of Complex Projective Manifolds. (arXiv:1807.11625v2 [math.DG] UPDATED) By arxiv.org Published On :: We prove an inequality between the sum of the Betti numbers of a complex projective manifold and its total curvature, and we characterize the complex projective manifolds whose total curvature is minimal. These results extend the classical theorems of Chern and Lashof to complex projective space. Full Article
ive Effective divisors on Hurwitz spaces. (arXiv:1804.01898v3 [math.AG] UPDATED) By arxiv.org Published On :: We prove the effectiveness of the canonical bundle of several Hurwitz spaces of degree k covers of the projective line from curves of genus 13<g<20. Full Article
ive Conservative stochastic 2-dimensional Cahn-Hilliard equation. (arXiv:1802.04141v2 [math.PR] UPDATED) By arxiv.org Published On :: We consider the stochastic 2-dimensional Cahn-Hilliard equation which is driven by the derivative in space of a space-time white noise. We use two different approaches to study this equation. First we prove that there exists a unique solution $Y$ to the shifted equation (see (1.4) below), then $X:=Y+{Z}$ is the unique solution to stochastic Cahn-Hilliard equaiton, where ${Z}$ is the corresponding O-U process. Moreover, we use Dirichlet form approach in cite{Albeverio:1991hk} to construct the probabilistically weak solution the the original equation (1.1) below. By clarifying the precise relation between the solutions obtained by the Dirichlet forms aprroach and $X$, we can also get the restricted Markov uniquness of the generator and the uniqueness of martingale solutions to the equation (1.1). Full Article
ive Surjective endomorphisms of projective surfaces -- the existence of infinitely many dense orbits. (arXiv:2005.03628v1 [math.AG]) By arxiv.org Published On :: Let $f colon X o X$ be a surjective endomorphism of a normal projective surface. When $operatorname{deg} f geq 2$, applying an (iteration of) $f$-equivariant minimal model program (EMMP), we determine the geometric structure of $X$. Using this, we extend the second author's result to singular surfaces to the extent that either $X$ has an $f$-invariant non-constant rational function, or $f$ has infinitely many Zariski-dense forward orbits; this result is also extended to Adelic topology (which is finer than Zariski topology). Full Article
ive Positive Geometries and Differential Forms with Non-Logarithmic Singularities I. (arXiv:2005.03612v1 [hep-th]) By arxiv.org Published On :: Positive geometries encode the physics of scattering amplitudes in flat space-time and the wavefunction of the universe in cosmology for a large class of models. Their unique canonical forms, providing such quantum mechanical observables, are characterised by having only logarithmic singularities along all the boundaries of the positive geometry. However, physical observables have logarithmic singularities just for a subset of theories. Thus, it becomes crucial to understand whether a similar paradigm can underlie their structure in more general cases. In this paper we start a systematic investigation of a geometric-combinatorial characterisation of differential forms with non-logarithmic singularities, focusing on projective polytopes and related meromorphic forms with multiple poles. We introduce the notions of covariant forms and covariant pairings. Covariant forms have poles only along the boundaries of the given polytope; moreover, their leading Laurent coefficients along any of the boundaries are still covariant forms on the specific boundary. Whereas meromorphic forms in covariant pairing with a polytope are associated to a specific (signed) triangulation, in which poles on spurious boundaries do not cancel completely, but their order is lowered. These meromorphic forms can be fully characterised if the polytope they are associated to is viewed as the restriction of a higher dimensional one onto a hyperplane. The canonical form of the latter can be mapped into a covariant form or a form in covariant pairing via a covariant restriction. We show how the geometry of the higher dimensional polytope determines the structure of these differential forms. Finally, we discuss how these notions are related to Jeffrey-Kirwan residues and cosmological polytopes. Full Article
ive On products of groups and indices not divisible by a given prime. (arXiv:2005.03608v1 [math.GR]) By arxiv.org Published On :: Let the group $G = AB$ be the product of subgroups $A$ and $B$, and let $p$ be a prime. We prove that $p$ does not divide the conjugacy class size (index) of each $p$-regular element of prime power order $xin Acup B$ if and only if $G$ is $p$-decomposable, i.e. $G=O_p(G) imes O_{p'}(G)$. Full Article
ive Steiner symmetry in the minimization of the principal positive eigenvalue of an eigenvalue problem with indefinite weight. (arXiv:2005.03581v1 [math.AP]) By arxiv.org Published On :: In cite{CC} the authors, investigating a model of population dynamics, find the following result. Let $Omegasubset mathbb{R}^N$, $Ngeq 1$, be a bounded smooth domain. The weighted eigenvalue problem $-Delta u =lambda m u $ in $Omega$ under homogeneous Dirichlet boundary conditions, where $lambda in mathbb{R}$ and $min L^infty(Omega)$, is considered. The authors prove the existence of minimizers $check m$ of the principal positive eigenvalue $lambda_1(m)$ when $m$ varies in a class $mathcal{M}$ of functions where average, maximum, and minimum values are given. A similar result is obtained in cite{CCP} when $m$ is in the class $mathcal{G}(m_0)$ of rearrangements of a fixed $m_0in L^infty(Omega)$. In our work we establish that, if $Omega$ is Steiner symmetric, then every minimizer in cite{CC,CCP} inherits the same kind of symmetry. Full Article
ive Derivatives of normal Jacobi operator on real hypersurfaces in the complex quadric. (arXiv:2005.03483v1 [math.DG]) By arxiv.org Published On :: In cite{S 2017}, Suh gave a non-existence theorem for Hopf real hypersurfaces in the complex quadric with parallel normal Jacobi operator. Motivated by this result, in this paper, we introduce some generalized conditions named $mathcal C$-parallel or Reeb parallel normal Jacobi operators. By using such weaker parallelisms of normal Jacobi operator, first we can assert a non-existence theorem of Hopf real hypersurfaces with $mathcal C$-parallel normal Jacobi operator in the complex quadric $Q^{m}$, $m geq 3$. Next, we prove that a Hopf real hypersurface has Reeb parallel normal Jacobi operator if and only if it has an $mathfrak A$-isotropic singular normal vector field. Full Article
ive Characteristic Points, Fundamental Cubic Form and Euler Characteristic of Projective Surfaces. (arXiv:2005.03481v1 [math.DG]) By arxiv.org Published On :: We define local indices for projective umbilics and godrons (also called cusps of Gauss) on generic smooth surfaces in projective 3-space. By means of these indices, we provide formulas that relate the algebraic numbers of those characteristic points on a surface (and on domains of the surface) with the Euler characteristic of that surface (resp. of those domains). These relations determine the possible coexistences of projective umbilics and godrons on the surface. Our study is based on a "fundamental cubic form" for which we provide a closed simple expression. Full Article
ive The formation of trapped surfaces in the gravitational collapse of spherically symmetric scalar fields with a positive cosmological constant. (arXiv:2005.03434v1 [gr-qc]) By arxiv.org Published On :: Given spherically symmetric characteristic initial data for the Einstein-scalar field system with a positive cosmological constant, we provide a criterion, in terms of the dimensionless size and dimensionless renormalized mass content of an annular region of the data, for the formation of a future trapped surface. This corresponds to an extension of Christodoulou's classical criterion by the inclusion of the cosmological term. Full Article
ive Type space functors and interpretations in positive logic. (arXiv:2005.03376v1 [math.LO]) By arxiv.org Published On :: We construct a 2-equivalence $mathfrak{CohTheory}^ ext{op} simeq mathfrak{TypeSpaceFunc}$. Here $mathfrak{CohTheory}$ is the 2-category of positive theories and $mathfrak{TypeSpaceFunc}$ is the 2-category of type space functors. We give a precise definition of interpretations for positive logic, which will be the 1-cells in $mathfrak{CohTheory}$. The 2-cells are definable homomorphisms. The 2-equivalence restricts to a duality of categories, making precise the philosophy that a theory is `the same' as the collection of its type spaces (i.e. its type space functor). In characterising those functors that arise as type space functors, we find that they are specific instances of (coherent) hyperdoctrines. This connects two different schools of thought on the logical structure of a theory. The key ingredient, the Deligne completeness theorem, arises from topos theory, where positive theories have been studied under the name of coherent theories. Full Article
ive Gaussian invariant measures and stationary solutions of 2D Primitive Equations. (arXiv:2005.03339v1 [math.PR]) By arxiv.org Published On :: We introduce a Gaussian measure formally preserved by the 2-dimensional Primitive Equations driven by additive Gaussian noise. Under such measure the stochastic equations under consideration are singular: we propose a solution theory based on the techniques developed by Gubinelli and Jara in cite{GuJa13} for a hyperviscous version of the equations. Full Article
ive Smooth non-projective equivariant completions of affine spaces. (arXiv:2005.03277v1 [math.AG]) By arxiv.org Published On :: In this paper we construct an equivariant embedding of the affine space $mathbb{A}^n$ with the translation group action into a complete non-projective algebraic variety $X$ for all $n geq 3$. The theory of toric varieties is used as the main tool for this construction. In the case of $n = 3$ we describe the orbit structure on the variety $X$. Full Article
ive A Note on Cores and Quasi Relative Interiors in Partially Finite Convex Programming. (arXiv:2005.03265v1 [math.FA]) By arxiv.org Published On :: The problem of minimizing an entropy functional subject to linear constraints is a useful example of partially finite convex programming. In the 1990s, Borwein and Lewis provided broad and easy-to-verify conditions that guarantee strong duality for such problems. Their approach is to construct a function in the quasi-relative interior of the relevant infinite-dimensional set, which assures the existence of a point in the core of the relevant finite-dimensional set. We revisit this problem, and provide an alternative proof by directly appealing to the definition of the core, rather than by relying on any properties of the quasi-relative interior. Our approach admits a minor relaxation of the linear independence requirements in Borwein and Lewis' framework, which allows us to work with certain piecewise-defined moment functions precluded by their conditions. We provide such a computed example that illustrates how this relaxation may be used to tame observed Gibbs phenomenon when the underlying data is discontinuous. The relaxation illustrates the understanding we may gain by tackling partially-finite problems from both the finite-dimensional and infinite-dimensional sides. The comparison of these two approaches is informative, as both proofs are constructive. Full Article
ive A Chance Constraint Predictive Control and Estimation Framework for Spacecraft Descent with Field Of View Constraints. (arXiv:2005.03245v1 [math.OC]) By arxiv.org Published On :: Recent studies of optimization methods and GNC of spacecraft near small bodies focusing on descent, landing, rendezvous, etc., with key safety constraints such as line-of-sight conic zones and soft landings have shown promising results; this paper considers descent missions to an asteroid surface with a constraint that consists of an onboard camera and asteroid surface markers while using a stochastic convex MPC law. An undermodeled asteroid gravity and spacecraft technology inspired measurement model is established to develop the constraint. Then a computationally light stochastic Linear Quadratic MPC strategy is presented to keep the spacecraft in satisfactory field of view of the surface markers while trajectory tracking, employing chance based constraints and up-to-date estimation uncertainty from navigation. The estimation uncertainty giving rise to the tightened constraints is particularly addressed. Results suggest robust tracking performance across a variety of trajectories. Full Article
ive Exponential decay for negative feedback loop with distributed delay. (arXiv:2005.03136v1 [math.DS]) By arxiv.org Published On :: We derive sufficient conditions for exponential decay of solutions of the delay negative feedback equation with distributed delay. The conditions are written in terms of exponential moments of the distribution. Our method only uses elementary tools of calculus and is robust towards possible extensions to more complex settings, in particular, systems of delay differential equations. We illustrate the applicability of the method to particular distributions - Dirac delta, Gamma distribution, uniform and truncated normal distributions. Full Article
ive Continuation of relative equilibria in the $n$--body problem to spaces of constant curvature. (arXiv:2005.03114v1 [math.DS]) By arxiv.org Published On :: We prove that all non-degenerate relative equilibria of the planar Newtonian $n$--body problem can be continued to spaces of constant curvature $kappa$, positive or negative, for small enough values of this parameter. We also compute the extension of some classical relative equilibria to curved spaces using numerical continuation. In particular, we extend Lagrange's triangle configuration with different masses to both positive and negative curvature spaces. Full Article
ive A note on Tonelli Lagrangian systems on $mathbb{T}^2$ with positive topological entropy on high energy level. (arXiv:2005.03108v1 [math.DS]) By arxiv.org Published On :: In this work we study the dynamical behavior Tonelli Lagrangian systems defined on the tangent bundle of the torus $mathbb{T}^2=mathbb{R}^2 / mathbb{Z}^2$. We prove that the Lagrangian flow restricted to a high energy level $ E_L^{-1}(c)$ (i.e $ c> c_0(L)$) has positive topological entropy if the flow satisfies the Kupka-Smale propriety in $ E_L^{-1}(c)$ (i.e, all closed orbit with energy $c$ are hyperbolic or elliptic and all heteroclinic intersections are transverse on $E_L^{-1}(c)$). The proof requires the use of well-known results in Aubry-Mather's Theory. Full Article
ive Homotopy invariance of the space of metrics with positive scalar curvature on manifolds with singularities. (arXiv:2005.03073v1 [math.AT]) By arxiv.org Published On :: In this paper we study manifolds $M_{Sigma}$ with fibered singularities, more specifically, a relevant space $Riem^{psc}(X_{Sigma})$ of Riemannian metrics with positive scalar curvature. Our main goal is to prove that the space $Riem^{psc}(X_{Sigma})$ is homotopy invariant under certain surgeries on $M_{Sigma}$. Full Article