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Scientists to Build Avian Tree of Life

From the National Science Foundation Birds — the only surviving descendants of dinosaurs — are used to study a large range of fundamental topics in biology, from understanding the evolution of mating systems to learning about the genetic and environmental … Continue reading




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California Study: Four Widely Used Neonicotinoid Pesticides Harm Bees

Center for Biological Diversity Press Release WASHINGTON – Four commonly used neonicotinoid pesticides can harm bees and other pollinators, according to a new analysis by California’s Department of Pesticide Regulation. The study found that current approved uses of the “neonics” … Continue reading




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Humanity ‘Sleepwalking Towards the Edge of a Cliff’: 60% of Earth’s Wildlife Wiped Out Since 1970

By Julia Conley Common Dreams “Nature is not a ‘nice to have’—it is our life-support system.” Scientists from around the world issued a stark warning to humanity Tuesday in a semi-annual report on the Earth’s declining biodiversity, which shows that … Continue reading




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Climate Change Driving Population Shifts to Urban Areas

By Kristie Auman-Bauer Penn State News Climate change is causing glaciers to shrink, temperatures to rise, and shifts in human migration in parts of the world, according to a Penn State researcher. Brian Thiede, assistant professor of rural sociology, along … Continue reading




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‘Utterly Terrifying’: Study Affirms Feedback Loop Fears as Surging Antarctica Ice Loss Tripled in Last Five Years

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



  • Climate & Climate Change
  • Climate Change ET
  • Antarctic
  • Antarctic ice sheet
  • Antartic ice loss
  • sea level rise

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Humanity ‘Sleepwalking Towards the Edge of a Cliff’: 60% of Earth’s Wildlife Wiped Out Since 1970

By Julia Conley Common Dreams “Nature is not a ‘nice to have’—it is our life-support system.” Scientists from around the world issued a stark warning to humanity Tuesday in a semi-annual report on the Earth’s declining biodiversity, which shows that … Continue reading




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Is UX Certification worth it?

BCS launched their Foundation Certificate in User Experience 3 years ago. We thought this was an opportune time to review its effectiveness. We contacted candidates who had taken (and passed) the certificate through Userfocus and asked, 'What impact has attaining the BCS Foundation Certificate in UX had on your job?' Ten key themes emerged.




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Talking to computers (part 1): Why is speech recognition so difficult?

Although the performance of today's speech recognition systems is impressive, the experience for many is still one of errors, corrections, frustration and abandoning speech in favour of alternative interaction methods. We take a closer look at speech and find out why speech recognition is so difficult.




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Does your website need to be beautiful?

When I first started designing websites in the 1990s, I focused most of my attention on creating striking visuals. In my defense, I was typically designing gaming website with only the occasional local business… but my goal was always to design a site that looked “cool.” In the early 2000s I stumbled across a website […]

The post Does your website need to be beautiful? appeared first on Psychology of Web Design | 3.7 Blog.




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How to Send SMS Notifications From WordPress (Step by Step)

Want to send SMS messages to your WordPress users? With automated SMS notification, you can keep your customers updated by sending order notification, shipment delivery status, cancellation notification, and more. In this article, we’ll show you how to send SMS messages to your WordPress users with ease. Sending Automated SMS Messages From WordPress SMS messages […]

The post How to Send SMS Notifications From WordPress (Step by Step) appeared first on IsItWP - Free WordPress Theme Detector.



  • WordPress Tutorials
  • send sms messages
  • send sms messages to wordpress users
  • send sms to wordpress users
  • sms messages to wordpress users

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Turning Your Life Around After TBI and PTSD

Adam shares an inspiring story about a friend with TBI and PTSD who almost ended his life but instead found the courage to ask for help — even though at the time he may not have known what that help looked like.




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Reestablishing a Social Life on Campus with Other Veterans and Civilians Post-TBI

Transitioning from military to civilian life can take time and can be tricky. Adam talks about how student veteran groups on college campuses can help vets reintegrate socially in their own way and  time.




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Customizing the User Registration Notification eMails

If a new user registers at a WordPress site the new user and the administrator receive notification mails: User: From: […]




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Article: 25 Beautifully Dark-Schemed Landing Pages for Inspiration

There is something instantly remarkable about a website with a strong, dark color scheme.





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How To Get UN-STUCK From Anything in Life That’s Got You Down [with Lewis Howes]

Ever felt STUCK with something in your life? Blocked, like you can’t get past this mental state, this hurdle, this creative block, this bad habit, this… Wait a minute. Why am I even asking that question? Of course you’ve been stuck before. We’ve literally ALL been stuck before. And by extension we all know how much it sucks to be in this state of mind. AND – on the flipside – how amazing it is when you can reclaim your life and get back to the things you want to be thinking, doing, and becoming. I’m obsessed with overcoming the mental blockers that try to keep me down – and I think it’s been a big piece of my personal success. Which is why I thought this little nugget might help. ENTER: Lewis Howes. My good friend Lewis Howes was in the studio shooting his newest CreativeLive course last week and I was able to snag him for a few minutes to chat about his new book and his amazingly simple, yet powerful process for reclaiming our lives and live our biggest dreams. In this episode, Lewis shares a powerful experience from his life and how- on reflection – it helped […]

The post How To Get UN-STUCK From Anything in Life That’s Got You Down [with Lewis Howes] appeared first on Chase Jarvis Photography.




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Design Your Life with Creative Calling + Debbie Millman

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.




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Dan Pink: If You Believe In It. Share It.

Dan Pink is a bestselling author and was the host & co-executive producer of “Crowd Control”, a television series about human behavior on National Geographic. He’s appeared frequently on NPR, PBS, ABC, CNN, and other TV/radio networks worldwide. His provocative books include Drive, A Whole New Mind, To Sell is Human, and his latest book, When: The Scientific Secrets of Perfect Timing. I love Dan’s books. He’s a ruthlessly practical thinker and in this episode he doesn’t hold back. We get into: How to see trends or unlikely connections across by absorbing and learning from a wide variety of sources, whether that’s audio programs, books, documentaries, or episodes of Silicon Valley. Using lists to track influences, sources, and even random ideas or curiosities to spark new ideas Selling isn’t a dirty word, it’s required to get our ideas out there. If we believe in our work, we have a moral obligation to share it. and so much more… Enjoy! FOLLOW DAN: 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 […]

The post Dan Pink: If You Believe In It. Share It. appeared first on Chase Jarvis Photography.




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My Favorite Gifts For Photographers Under $100(ish)

Every holiday season, I get an influx of DMs, tweets, texts and messages from followers, friends and family asking for my photo gear recommendations. This year, rather than putting together a list of all the high-tech cameras and lenses that come with high-price tags to match – I wanted share some affordable add-ons that thrifty photographers should have in their arsenal. As I like to say, the best camera is the one you have with you and most of the time that’s the one in your pocket ????  If you are looking for gift ideas for the photographer on your list these are my go-tos under $100(ish).   Moment Lens  These pocket size lenses will transform your mobile device into a lightweight DSLR. With a variety of lenses from fisheye to macro, Moment add-ons are durable, easy-to-use and have incredible clarity. Compatible with almost every smartphone, these compact lens take the camera in your pocket up a notch.          Shure Mic Shure has transformed mobile audio with its line of mobile mics. Regardless of your price point, the audio company creates options that will take your sound from distorted to crystal clear. As a photographer and podcaster […]

The post My Favorite Gifts For Photographers Under $100(ish) appeared first on Chase Jarvis Photography.




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Ben Moon: Surf, Survival, and Life on the Road

Since we’re home, I’m working to bring more LIVE conversations to you from our living rooms. ???? Join me + adventure photographer / filmmaker Ben Moon at 12:30PM PST tomorrow. There will be a live chat, so please ask us some questions as well. See you there. You might know Ben from his adventure and lifestyle photography or his beautiful films. Surviving cancer in his 20s gradually shifted his artistic focus from capturing the pursuit of adventure to telling nuanced human stories that have inspired and impacted millions. Most notably, his personal story battling colorectal cancer and his special relationship with his dog Denali, which he shares in his beautiful viral short film, now turned book, Denali. ABOUT BEN Ben Moon is an adventure, lifestyle, and portrait photographer whose vibrant images have graced the pages of Patagonia catalogues for the past 18 years.  In recent years, he has shifted his focus to filmmaking. In 2015, he founded his production company, Moonhouse as a platform for collaboration with friends and creatives to bring a wide range of thought-provoking, impactful and cinematically beautiful stories to life on-screen. As a director, Ben’s unique ability to connect with his subjects paired with the talent […]

The post Ben Moon: Surf, Survival, and Life on the Road appeared first on Chase Jarvis Photography.




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Pursuing A Professional Certification In Scrum

Professional certifications have become increasingly popular in this age of career switchers and the freelance gig economy. A certification can be a useful way to advance your skill set quickly or make your resume stand out, which can be especially important for those trying to break into a new industry or attract business while self-employed. Whatever your reason may be for pursuing a professional certificate, there is one question only you can answer for yourself: is it worth it?

Finding first-hand experiences from professionals with similar career goals and passions was the most helpful research I used to answer that question for myself. So, here’s mine; why I decided to get Scrum certified, how I evaluated my options, and if it was really worth it.

A shift in mindset

My background originates in brand strategy where it’s typical for work to follow a predictable order, each step informing the next. This made linear techniques like water-fall timelines, completing one phase of work in its entirety before moving onto the next, and documenting granular tasks weeks in advance helpful and easy to implement. When I made the move to more digitally focused work, tasks followed a much looser set of ‘typical’ milestones. While the general outline remained the same (strategy, design, development, launch) there was a lot more overlap with how tasks informed each other, and would keep informing and re-informing as an iterative workflow would encourage.

Trying to fit a very fluid process into my very stiff linear approach to project planning didn’t work so well. I didn’t have the right strategies to manage risks in a productive way without feeling like the whole project was off track; with the habit of account for granular details all the time, I struggled to lean on others to help define what we should work on and when, and being okay if that changed once, or twice, or three times. Everything I learned about the process of product development came from learning on the job and making a ton of mistakes—and I knew I wanted to get better.

Photo by Christin Hume on Unsplash

I was fortunate enough to work with a group of developers who were looking to make a change, too. Being ‘agile’-enthusiasts, this group of developers were desperately looking for ways to infuse our approach to product work with agile-minded principles (the broad definition of ‘agile’ comes from ‘The Agile Manifesto’, which has influenced frameworks for organizing people and information, often applied in product development). This not only applied to how I worked with them, but how they worked with each other, and the way we all onboarded clients to these new expectations. This was a huge eye opener to me. Soon enough, I started applying these agile strategies to my day-to-day— running stand-ups, setting up backlogs, and reorganizing the way I thought about work output. It’s from this experience that I decided it may be worth learning these principles more formally.

The choice to get certified

There is a lot of literature out there about agile methodologies and a lot to be learned from casual research. This benefitted me for a while until I started to work on more complicated projects, or projects with more ambitious feature requests. My decision to ultimately pursue a formal agile certification really came down to three things:

  1. An increased use of agile methods across my team. Within my day-to-day I would encounter more team members who were familiar with these tactics and wanted to use them to structure the projects they worked on.
  2. The need for a clear definition of what processes to follow. I needed to grasp a real understanding of how to implement agile processes and stay consistent with using them to be an effective champion of these principles.
  3. Being able to diversify my experience. Finding ways to differentiate my resume from others with similar experience would be an added benefit to getting a certification. If nothing else, it would demonstrate that I’m curious-minded and proactive about my career.

To achieve these things, I gravitated towards a more foundational education in a specific agile-methodology. This made Scrum the most logical choice given it’s the basis for many of the agile strategies out there and its dominance in the field.

Evaluating all the options

For Scrum education and certification, there are really two major players to consider.

  1. Scrum Alliance - Probably the most well known Scrum organization is Scrum Alliance. They are a highly recognizable organization that does a lot to further the broader understanding of Scrum as a practice.
  2. Scrum.org - Led by the original co-founder of Scrum, Ken Schwaber, Scrum.org is well-respected and touted for its authority in the industry.

Each has their own approach to teaching and awarding certifications as well as differences in price point and course style that are important to be aware of.

SCRUM ALLIANCE

Pros

  • Strong name recognition and leaders in the Scrum field
  • Offers both in-person and online courses
  • Hosts in-person events, webinars, and global conferences
  • Provides robust amounts of educational resources for its members
  • Has specialization tracks for folks looking to apply Scrum to their specific discipline
  • Members are required to keep their skills up to date by earning educational credits throughout the year to retain their certification
  • Consistent information across all course administrators ensuring you'll be set up to succeed when taking your certification test.

Cons

  • High cost creates a significant barrier to entry (we’re talking in the thousands of dollars here)
  • Courses are required to take the certification test
  • Certification expires after two years, requiring additional investment in time and/or money to retain credentials
  • Difficult to find sample course material ahead of committing to a course
  • Courses are several days long which may mean taking time away from a day job to complete them

SCRUM.ORG

Pros

  • Strong clout due to its founder, Ken Schwaber, who is the originator of Scrum
  • Offers in-person classes and self-paced options
  • Hosts in-person events and meetups around the world
  • Provides free resources and materials to the public, including practice tests
  • Has specialization tracks for folks looking to apply Scrum to their specific discipline
  • Minimum score on certification test required to pass; certification lasts for life
  • Lower cost for certification when compared to peers

Cons

  • Much lesser known to the general public, as compared to its counterpart
  • Less sophisticated educational resources (mostly confined to PDFs or online forums) making digesting the material challenging
  • Practice tests are slightly out of date making them less effective as a study tool
  • Self-paced education is not structured and therefore can’t ensure you’re learning everything you need to know for the test
  • Lack of active and engaging community will leave something to be desired

Before coming to a decision, it was helpful to me to weigh these pros and cons against a set of criteria. Here’s a helpful scorecard I used to compare the two institutions.

Scrum Alliance Scrum.org
Affordability ⚪⚪⚪
Rigor⚪⚪⚪⚪⚪
Reputation⚪⚪⚪⚪⚪
Recognition⚪⚪⚪
Community⚪⚪⚪
Access⚪⚪⚪⚪⚪
Flexibility⚪⚪⚪
Specialization⚪⚪⚪⚪⚪⚪
Requirements⚪⚪⚪
Longevity⚪⚪⚪

For me, the four areas that were most important to me were:

  • Affordability - I’d be self-funding this certificate so the investment of cost would need to be manageable.
  • Self-paced - Not having a lot of time to devote in one sitting, the ability to chip away at coursework was appealing to me.
  • Reputation - Having a certificate backed by a well-respected institution was important to me if I was going to put in the time to achieve this credential.
  • Access - Because I wanted to be a champion for this framework for others in my organization, having access to resources and materials would help me do that more effectively.

Ultimately, I decided upon a Professional Scrum Master certification from Scrum.org! The price and flexibility of learning course content were most important to me. I found a ton of free materials on Scrum.org that I could study myself and their practice tests gave me a good idea of how well I was progressing before I committed to the cost of actually taking the test. And, the pedigree of certification felt comparable to that of Scrum Alliance, especially considering that the founder of Scrum himself ran the organization.

Putting a certificate to good use

I don’t work in a formal Agile company, and not everyone I work with knows the ins and outs of Scrum. I didn’t use my certification to leverage a career change or new job title. So after all that time, money, and energy, was it worth it?

I think so. I feel like I use my certification every day and employ many of the principles of Scrum in my day-to-day management of projects and people.

  • Self-organizing teams is really important when fostering trust and collaboration among project members. This means leaning on each other’s past experiences and lessons learned to inform our own approach to work. It also means taking a step back as a project manager to recognize the strengths on your team and trust their lead.
  • Approaching things in bite size pieces is also a best practice I use every day. Even when there isn't a mandated sprint rhythm, breaking things down into effort level, goals, and requirements is an excellent way to approach work confidently and avoid getting too overwhelmed.
  • Retrospectives and stand ups are also absolute musts for Scrum practices, and these can be modified to work for companies and project teams of all shapes and sizes. Keeping a practice of collective communication and reflection will keep a team humming and provides a safe space to vent and improve.
Photo by Gautam Lakum on Unsplash

Parting advice

I think furthering your understanding of industry standards and keeping yourself open to new ways of working will always benefit you as a professional. Professional certifications are readily available and may be more relevant than ever.

If you’re on this path, good luck! And here are some things to consider:

  • Do your research – With so many educational institutions out there, you can definitely find the right one for you, with the level of rigor you’re looking for.
  • Look for company credits or incentives – some companies cover part or all of the cost for continuing education.
  • Get started ASAP – You don’t need a full certification to start implementing small tactics to your workflows. Implementing learnings gradually will help you determine if it’s really something you want to pursue more formally.




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Old and broken – but oh so beautiful

For years now I’ve had a thing for old doorways with big old locks – now on Cyprus it escalated a bit due to the number of absolutely beautiful old doors. Many of them not restored but broken or run […]




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The Canon EOS R5 release gets closer as it passes Bluetooth certification

We’re a big step closer to a Canon EOS R5 release announcement now, as Nokishita Tweets that it has passed its Bluetooth certification. The belief is that the EOS R5 was originally scheduled to ship in July, and Canon Rumors reports that they’ve been told that’ll still happen. With lockdowns still in effect in much […]

The post The Canon EOS R5 release gets closer as it passes Bluetooth certification appeared first on DIY Photography.




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Photography Life makes all their paid premium courses free

Photography Life has just contributed to the selection of online courses that you can take for free. While their premim courses are normally paid $150 per course, you can now access them free of charge. The founders have released them on YouTube, available for everyone to watch. The Photography Life team came to the decision […]

The post Photography Life makes all their paid premium courses free appeared first on DIY Photography.




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Prolific, the (Much Better) Mechnical Turk Alternative

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 […]




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Almost invariant subspaces of the shift operator on vector-valued Hardy spaces. (arXiv:2005.02243v2 [math.FA] UPDATED)

In this article, we characterize nearly invariant subspaces of finite defect for the backward shift operator acting on the vector-valued Hardy space which is a vectorial generalization of a result of Chalendar-Gallardo-Partington (C-G-P). Using this characterization of nearly invariant subspace under the backward shift we completely describe the almost invariant subspaces for the shift and its adjoint acting on the vector valued Hardy space.




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Differentiating through Log-Log Convex Programs. (arXiv:2004.12553v2 [math.OC] UPDATED)

We show how to efficiently compute the derivative (when it exists) of the solution map of log-log convex programs (LLCPs). These are nonconvex, nonsmooth optimization problems with positive variables that become convex when the variables, objective functions, and constraint functions are replaced with their logs. We focus specifically on LLCPs generated by disciplined geometric programming, a grammar consisting of a set of atomic functions with known log-log curvature and a composition rule for combining them. We represent a parametrized LLCP as the composition of a smooth transformation of parameters, a convex optimization problem, and an exponential transformation of the convex optimization problem's solution. The derivative of this composition can be computed efficiently, using recently developed methods for differentiating through convex optimization problems. We implement our method in CVXPY, a Python-embedded modeling language and rewriting system for convex optimization. In just a few lines of code, a user can specify a parametrized LLCP, solve it, and evaluate the derivative or its adjoint at a vector. This makes it possible to conduct sensitivity analyses of solutions, given perturbations to the parameters, and to compute the gradient of a function of the solution with respect to the parameters. We use the adjoint of the derivative to implement differentiable log-log convex optimization layers in PyTorch and TensorFlow. Finally, we present applications to designing queuing systems and fitting structured prediction models.




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Convergent normal forms for five dimensional totally nondegenerate CR manifolds in C^4. (arXiv:2004.11251v2 [math.CV] UPDATED)

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.




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Automorphisms of shift spaces and the Higman--Thomspon groups: the one-sided case. (arXiv:2004.08478v2 [math.GR] UPDATED)

Let $1 le r < n$ be integers. We give a proof that the group $mathop{mathrm{Aut}}({X_{n}^{mathbb{N}}, sigma_{n}})$ of automorphisms of the one-sided shift on $n$ letters embeds naturally as a subgroup $mathcal{h}_{n}$ of the outer automorphism group $mathop{mathrm{Out}}(G_{n,r})$ of the Higman-Thompson group $G_{n,r}$. From this, we can represent the elements of $mathop{mathrm{Aut}}({X_{n}^{mathbb{N}}, sigma_{n}})$ by finite state non-initial transducers admitting a very strong synchronizing condition.

Let $H in mathcal{H}_{n}$ and write $|H|$ for the number of states of the minimal transducer representing $H$. We show that $H$ can be written as a product of at most $|H|$ torsion elements. This result strengthens a similar result of Boyle, Franks and Kitchens, where the decomposition involves more complex torsion elements and also does not support practical extit{a priori} estimates of the length of the resulting product.

We also give new proofs of some known results about $mathop{mathrm{Aut}}({X_{n}^{mathbb{N}}, sigma_{n}})$.




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Co-Seifert Fibrations of Compact Flat Orbifolds. (arXiv:2002.12799v2 [math.GT] UPDATED)

In this paper, we develop the theory for classifying all the geometric fibrations of compact, connected, flat $n$-orbifolds, over a 1-orbifold, up to affine equivalence. We apply our classification theory to classify all the geometric fibrations of compact, connected, flat $2$-orbifolds, over a 1-orbifold, up to affine equivalence. This paper is an essential part of our project to give a geometric proof of the classification of all closed flat 4-manifolds.




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Compact manifolds of dimension $ngeq 12$ with positive isotropic curvature. (arXiv:1909.12265v4 [math.DG] UPDATED)

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.




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Topology Identification of Heterogeneous Networks: Identifiability and Reconstruction. (arXiv:1909.11054v2 [math.OC] UPDATED)

This paper addresses the problem of identifying the graph structure of a dynamical network using measured input/output data. This problem is known as topology identification and has received considerable attention in recent literature. Most existing literature focuses on topology identification for networks with node dynamics modeled by single integrators or single-input single-output (SISO) systems. The goal of the current paper is to identify the topology of a more general class of heterogeneous networks, in which the dynamics of the nodes are modeled by general (possibly distinct) linear systems. Our two main contributions are the following. First, we establish conditions for topological identifiability, i.e., conditions under which the network topology can be uniquely reconstructed from measured data. We also specialize our results to homogeneous networks of SISO systems and we will see that such networks have quite particular identifiability properties. Secondly, we develop a topology identification method that reconstructs the network topology from input/output data. The solution of a generalized Sylvester equation will play an important role in our identification scheme.




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On the Total Curvature and Betti Numbers of Complex Projective Manifolds. (arXiv:1807.11625v2 [math.DG] UPDATED)

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.




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Simulation of Integro-Differential Equation and Application in Estimation of Ruin Probability with Mixed Fractional Brownian Motion. (arXiv:1709.03418v6 [math.PR] UPDATED)

In this paper, we are concerned with the numerical solution of one type integro-differential equation by a probability method based on the fundamental martingale of mixed Gaussian processes. As an application, we will try to simulate the estimation of ruin probability with an unknown parameter driven not by the classical L'evy process but by the mixed fractional Brownian motion.




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Local mollification of Riemannian metrics using Ricci flow, and Ricci limit spaces. (arXiv:1706.09490v2 [math.DG] UPDATED)

We use Ricci flow to obtain a local bi-Holder correspondence between Ricci limit spaces in three dimensions and smooth manifolds. This is more than a complete resolution of the three-dimensional case of the conjecture of Anderson-Cheeger-Colding-Tian, describing how Ricci limit spaces in three dimensions must be homeomorphic to manifolds, and we obtain this in the most general, locally non-collapsed case. The proofs build on results and ideas from recent papers of Hochard and the current authors.




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The classification of Rokhlin flows on C*-algebras. (arXiv:1706.09276v6 [math.OA] UPDATED)

We study flows on C*-algebras with the Rokhlin property. We show that every Kirchberg algebra carries a unique Rokhlin flow up to cocycle conjugacy, which confirms a long-standing conjecture of Kishimoto. We moreover present a classification theory for Rokhlin flows on C*-algebras satisfying certain technical properties, which hold for many C*-algebras covered by the Elliott program. As a consequence, we obtain the following further classification theorems for Rokhlin flows. Firstly, we extend the statement of Kishimoto's conjecture to the non-simple case: Up to cocycle conjugacy, a Rokhlin flow on a separable, nuclear, strongly purely infinite C*-algebra is uniquely determined by its induced action on the prime ideal space. Secondly, we give a complete classification of Rokhlin flows on simple classifiable $KK$-contractible C*-algebras: Two Rokhlin flows on such a C*-algebra are cocycle conjugate if and only if their induced actions on the cone of lower-semicontinuous traces are affinely conjugate.




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Categorification via blocks of modular representations for sl(n). (arXiv:1612.06941v3 [math.RT] UPDATED)

Bernstein, Frenkel, and Khovanov have constructed a categorification of tensor products of the standard representation of $mathfrak{sl}_2$, where they use singular blocks of category $mathcal{O}$ for $mathfrak{sl}_n$ and translation functors. Here we construct a positive characteristic analogue using blocks of representations of $mathfrak{sl}_n$ over a field $ extbf{k}$ of characteristic $p$ with zero Frobenius character, and singular Harish-Chandra character. We show that the aforementioned categorification admits a Koszul graded lift, which is equivalent to a geometric categorification constructed by Cautis, Kamnitzer, and Licata using coherent sheaves on cotangent bundles to Grassmanians. In particular, the latter admits an abelian refinement. With respect to this abelian refinement, the stratified Mukai flop induces a perverse equivalence on the derived categories for complementary Grassmanians. This is part of a larger project to give a combinatorial approach to Lusztig's conjectures for representations of Lie algebras in positive characteristic.




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On Harmonic and Asymptotically harmonic Finsler manifolds. (arXiv:2005.03616v1 [math.DG])

In this paper we introduce various types of harmonic Finsler manifolds and study the relation between them. We give several characterizations of such spaces in terms of the mean curvature and Laplacian. In addition, we prove that some harmonic Finsler manifolds are of Einstein type and a technique to construct harmonic Finsler manifolds of Rander type is given. Moreover, we provide many examples of non-Riemmanian Finsler harmonic manifolds of constant flag curvature and constant $S$-curvature. Finally, we analyze Busemann functions in a general Finsler setting and in certain kind of Finsler harmonic manifolds, namely asymptotically harmonic Finsler manifolds along with studying some applications. In particular, we show the Busemann function is smooth in asymptotically harmonic Finsler manifolds and the total Busemann function is continuous in $C^{infty}$ topology.




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Positive Geometries and Differential Forms with Non-Logarithmic Singularities I. (arXiv:2005.03612v1 [hep-th])

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.




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Twisted quadrics and algebraic submanifolds in R^n. (arXiv:2005.03509v1 [math-ph])

We propose a general procedure to construct noncommutative deformations of an algebraic submanifold $M$ of $mathbb{R}^n$, specializing the procedure [G. Fiore, T. Weber, Twisted submanifolds of $mathbb{R}^n$, arXiv:2003.03854] valid for smooth submanifolds. We use the framework of twisted differential geometry of [Aschieri et al.,Class. Quantum Gravity 23 (2006), 1883], whereby the commutative pointwise product is replaced by the $star$-product determined by a Drinfel'd twist. We actually simultaneously construct noncommutative deformations of all the algebraic submanifolds $M_c$ that are level sets of the $f^a(x)$, where $f^a(x)=0$ are the polynomial equations solved by the points of $M$, employing twists based on the Lie algebra $Xi_t$ of vector fields that are tangent to all the $M_c$. The twisted Cartan calculus is automatically equivariant under twisted $Xi_t$. If we endow $mathbb{R}^n$ with a metric, then twisting and projecting to normal or tangent components commute, projecting the Levi-Civita connection to the twisted $M$ is consistent, and in particular a twisted Gauss theorem holds, provided the twist is based on Killing vector fields. Twisted algebraic quadrics can be characterized in terms of generators and $star$-polynomial relations. We explicitly work out deformations based on abelian or Jordanian twists of all quadrics in $mathbb{R}^3$ except ellipsoids, in particular twisted cylinders embedded in twisted Euclidean $mathbb{R}^3$ and twisted hyperboloids embedded in twisted Minkowski $mathbb{R}^3$ [the latter are twisted (anti-)de Sitter spaces $dS_2,AdS_2$].




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A reaction-diffusion system to better comprehend the unlockdown: Application of SEIR-type model with diffusion to the spatial spread of COVID-19 in France. (arXiv:2005.03499v1 [q-bio.PE])

A reaction-diffusion model was developed describing the spread of the COVID-19 virus considering the mean daily movement of susceptible, exposed and asymptomatic individuals. The model was calibrated using data on the confirmed infection and death from France as well as their initial spatial distribution. First, the system of partial differential equations is studied, then the basic reproduction number, R0 is derived. Second, numerical simulations, based on a combination of level-set and finite differences, shown the spatial spread of COVID-19 from March 16 to June 16. Finally, scenarios of unlockdown are compared according to variation of distancing, or partially spatial lockdown.




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Minimum pair degree condition for tight Hamiltonian cycles in $4$-uniform hypergraphs. (arXiv:2005.03391v1 [math.CO])

We show that every 4-uniform hypergraph with $n$ vertices and minimum pair degree at least $(5/9+o(1))n^2/2$ contains a tight Hamiltonian cycle. This degree condition is asymptotically optimal.




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A remark on the Laplacian flow and the modified Laplacian co-flow in G2-Geometry. (arXiv:2005.03332v1 [math.DG])

We observe that the DeTurck Laplacian flow of G2-structures introduced by Bryant and Xu as a gauge fixing of the Laplacian flow can be regarded as a flow of G2-structures (not necessarily closed) which fits in the general framework introduced by Hamilton in [4].




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Linear independence of generalized Poincar'{e} series for anti-de Sitter $3$-manifolds. (arXiv:2005.03308v1 [math.SP])

Let $Gamma$ be a discrete group acting properly discontinuously and isometrically on the three-dimensional anti-de Sitter space $mathrm{AdS}^{3}$, and $square$ the Laplacian which is a second-order hyperbolic differential operator. We study linear independence of a family of generalized Poincar'{e} series introduced by Kassel-Kobayashi [Adv. Math. 2016], which are defined by the $Gamma$-average of certain eigenfunctions on $mathrm{AdS}^{3}$. We prove that the multiplicities of $L^{2}$-eigenvalues of the hyperbolic Laplacian $square$ on $Gammaackslashmathrm{AdS}^{3}$ are unbounded when $Gamma$ is finitely generated. Moreover, we prove that the multiplicities of extit{stable $L^{2}$-eigenvalues} for compact anti-de Sitter $3$-manifolds are unbounded.




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Fourier transformation and stability of differential equation on $L^1(Bbb{R})$. (arXiv:2005.03296v1 [math.FA])

In the present paper by the Fourier transform we show that every linear differential equations of $n$-th order has a solution in $L^1(Bbb{R})$ which is infinitely differentiable in $Bbb{R} setminus {0}$. Moreover the Hyers-Ulam stability of such equations on $L^1(Bbb{R})$ is investigated.




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Non-relativity of K"ahler manifold and complex space forms. (arXiv:2005.03208v1 [math.CV])

We study the non-relativity for two real analytic K"ahler manifolds and complex space forms of three types. The first one is a K"ahler manifold whose polarization of local K"ahler potential is a Nash function in a local coordinate. The second one is the Hartogs domain equpped with two canonical metrics whose polarizations of the K"ahler potentials are the diastatic functions.




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Anti-symplectic involutions on rational symplectic 4-manifolds. (arXiv:2005.03142v1 [math.SG])

This is an expanded version of the talk given be the first author at the conference "Topology, Geometry, and Dynamics: Rokhlin - 100". The purpose of this talk was to explain our current results on classification of rational symplectic 4-manifolds equipped with an anti-symplectic involution. Detailed exposition will appear elsewhere.




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On planar graphs of uniform polynomial growth. (arXiv:2005.03139v1 [math.PR])

Consider an infinite planar graph with uniform polynomial growth of degree d > 2. Many examples of such graphs exhibit similar geometric and spectral properties, and it has been conjectured that this is necessary. We present a family of counterexamples. In particular, we show that for every rational d > 2, there is a planar graph with uniform polynomial growth of degree d on which the random walk is transient, disproving a conjecture of Benjamini (2011).

By a well-known theorem of Benjamini and Schramm, such a graph cannot be a unimodular random graph. We also give examples of unimodular random planar graphs of uniform polynomial growth with unexpected properties. For instance, graphs of (almost sure) uniform polynomial growth of every rational degree d > 2 for which the speed exponent of the walk is larger than 1/d, and in which the complements of all balls are connected. This resolves negatively two questions of Benjamini and Papasoglou (2011).