Digital Commons Network^™

Finite Symmetries Of S^4, Weimin Chen Chen, Slawomir Kwasik, Reinhard Shultz

Weimin Chen

This paper discusses topological and locally linear actions of finite groups on S4. Local linearity of the orientation preserving actions on S4 forces the group to be a subgroup of SO(5). On the other hand, orientation reversing topological actions of “exotic” groups G (i.e. G 6⊂ O(5)) on S4 are constructed, and local linearity and stable smoothability of the actions are studied.

Ropelength Criticality, Jason Cantarella, Joseph H.G. Fu, Robert B. Kusner, John M. Sullivan

Robert Kusner

The ropelength problem asks for the minimum-length configuration of a knotted diameter-one tube embedded in Euclidean three-space. The core curve of such a tube is called a tight knot, and its length is a knot invariant measuring complexity. In terms of the core curve, the thickness constraint has two parts: an upper bound on curvature and a self-contact condition.

We give a set of necessary and sufficient conditions for criticality with respect to this constraint, based on a version of the Kuhn–Tucker theorem that we established in previous work. The key technical difficulty is to compute the derivative of thickness …

Vimos Ultra-Deep Survey (Vuds): Witnessing The Assembly Of A Massive Cluster At Z~3.3, B.C. Lemaux, O. Cucciati, L.A.M. Tasca, O. Le Fevre, G. Zamorani, P. Cassata, B. Garilli, V. Le Brun, D. Maccagni, L. Pentericci, R. Thomas, E. Vanzella, E. Zucca, R. Amorin, S. Bardelli, P. Capak, L.P. Cassara, M. Castellano, A. Cimatti, J.G. Cuby, S. De La Torre, A. Durkalec, A. Fontana, Mauro Giavalisco, A. Grazian, N.P. Hathi, O. Ilbert, C. Moreau, S. Paltani, B. Ribeiro, M. Salvato, D. Schaerer, M Scodeggio, V. Sommariva, M. Talia, Y. Taniguchi, L. Tresse, D. Vergani, P.W. Wang, S. Charlot, T. Contini, S. Fotopoulou, R.R. Gal, D.D. Kocevski, C. Lopez-Sanjuan, L.M. Lubin, Y. Mellier, T. Sadibekova, N. Scoville

Mauro Giavalisco

Using new spectroscopic observations obtained as part of the VIMOS Ultra-Deep Survey (VUDS), we performed a systematic search for overdense environments in the early universe (z> 2) and report here on the discovery of Cl J0227-0421, a massive protocluster at z = 3.29. This protocluster is characterized by both the large overdensity of spectroscopically confirmed members, δgal = 10.5 ± 2.8, and a significant overdensity in photometric redshift members. The halo mass of this protocluster is estimated by a variety of methods to be ~3 × 1014ℳ⊙ at z ~ 3.3, which, evolved to z = 0 results in a …

A Mean-Field Analogue Of The Hong-Ou-Mandel Experiment With Bright Solitons, Zhi-Yuan Sun, Panos Kevrekidis, Peter Kruger

Panos Kevrekidis

In the present work, we theoretically propose and numerically illustrate a mean-field analog of the Hong-Ou-Mandel experiment with bright solitons. More specifically, we scatter two solitons off of each other (in our setup, the bright solitons play the role of a classical analog to the quantum photons of the original experiment), while the role of the beam splitter is played by a repulsive Gaussian barrier. In our classical scenario, distinguishability of the particles yields, as expected, a 0.5 split mass on either side. Nevertheless, for very slight deviations from the completely symmetric scenario, a near-perfect transmission can be constructed instead, …

A Comparative Analysis Of Numerical Approaches To The Mechanics Of Elastic Sheets, Michael Taylor, Benny Davidovitch, Zhanlong Qiu, Katia Bertoldi

Benny Davidovitch

No abstract provided.

Hands Across The University: Partnering To Advance Scholarly Communication, Marilyn S. Billings

Marilyn S. Billings

The University of Massachusetts – Amherst, the flagship campus of the University of Massachusetts system, has long been a leader in exploring new models of scholarly communication with a particular emphasis on partnering with faculty. The library has been key in the Open Education Initiative at the university, working closely with the Office of the Provost. This presentation will describe the services developed by the library, particularly through its institutional repository – ScholarWorks@UMass Amherst – and how these services have facilitated new partnerships and relationships with faculty and other stakeholders across the university. It will provide practical advice on the …

A Sheet On Deformable Sphere: "Wrinklogami" Patterns Suppress Curvature-Induced Delamination, Evan Hohlfeld, Benny Davidovitch

Benny Davidovitch

No abstract provided.

Chemical Potential In The First Law For Holographic Entanglement Entropy, David Kastor, Sourya Ray, Jennie Traschen

David Kastor

Entanglement entropy in conformal field theories is known to satisfy a first law. For spherical entangling surfaces, this has been shown to follow via the AdS/CFT correspondence and the holographic prescription for entanglement entropy from the bulk first law for Killing horizons. The bulk first law can be extended to include variations in the cosmological constant Λ, which we established in earlier work. Here we show that this implies an extension of the boundary first law to include varying the number of degrees of freedom of the boundary CFT. The thermodynamic potential conjugate to Λ in the bulk is called …

Innovative Representations Of Light, Behaving As Both Particles And Waves, Among The Paintings Of Monet And Renoir, Charles Smith

Charles Kay Smith

Monet and Renoir, friends collaborating in open air about 1865, discovered that sunlight filtering through a canopy of tree leaves does not produce the splotches and dapples that studio artists conventionally represented at the time but circles of light. Sometimes the circles of light punctuating the shade are clear, separate and crisp, as though light is being propagated as particles, but if the pin-hole gaps between leaves are very close together, they will project compound or superimposed circles that look like the waves that Thomas Young saw in his double slit experiment in 1803-4. Newton’s Opticks published in 1704 had …

Non-Vacuum Ads Cosmologies And The Approach To Equilibrium Of Entanglement Entropy, Sebastian Fischetti, David Kastor, Jennie Traschen

David Kastor

We extend standard results for vacuum asymptotically locally AdS (AlAdS) spacetimes, showing that such spacetimes can be constructed as foliations where the induced metric on each hypersurface satisfies Einstein's equation with stress-energy. By an appropriate choice of stress-energy on the hypersurfaces, the resulting AlAdS spacetime satisfies Einstein's equation with a negative cosmological constant and physical stress tensor. We use this construction to obtain AlAdS solutions whose boundaries are FRW cosmologies sourced by a massless scalar field or by a perfect fluid obeying the strong energy condition. We focus on FRW universes that approach Minkowski spacetime at late times, yielding AlAdS …

Shadows Know, A Poem 11/12/2014, Charles Smith

Charles Kay Smith

Partly written during an illness several years ago; I finished it last year.

Crystal Graphs, Tokuyama's Theorem, And The Gindikin-Karpelevic Formula For G2, Holley Friedlander, Louis Gaudet, Paul E. Gunnells

Paul Gunnells

We conjecture a deformation of the Weyl character formula for type G2 in the spirit of Tokuyama’s formula for type A . Using our conjecture, we prove a combinatorial version of the Gindikin–Karpelevič formula for G2 , in the spirit of Bump–Nakasuji’s formula for type A .

Collection Development And Data Visualization: How Interactive Graphic Displays Are Transforming Collection Development Decisions, Paulina Borrego, Rachel Lewellen

Paulina Borrego

No abstract provided.

Western Women, Physicality And Movement In India: On Learning Kabaddi, Todd Crosset

Todd Crosset

No abstract provided.

Libraries Leading The Way On The Textbook Problem, Marilyn S. Billings, Charlotte Roh, William M. Cross, Brendon O'Connell

Marilyn S. Billings

No abstract provided.

Spreading The Word, Building A Community: Vision For A National Oer Movement, Nicole Allen, Steven J. Bell, Marilyn S. Billings

Marilyn S. Billings

Three experts in the use of open education resources as alternatives to high-cost textbooks describe their work and argue for the development of a national OER movement in higher education.

Flax: Food And Fiber, Madeleine K. Charney

Madeleine K. Charney

Highlights the versatile and nutritious flax plant, now cultivated worldwide.

Dissipative Superfluid Mass Flux Through Solid 4he, Ye. Vekhov, Robert Hallock

Robert Hallock

The thermomechanical effect in superfluid helium is used to create an initial chemical potential difference ∆u_0 across a solid 4_He sample. This ∆u_0 causes a flow of helium atoms from one reservoir filled with superfluid helium, through a sample cell filled with solid helium, to another superfluid-filled reservoir until potential equilibrium between the reservoirs is restored. The solid helium sample is separated from each of the reservoirs by Vycor rods that allow only the superfluid component to flow. With an improved technique, measurements of the flow F at several fixed solid helium temperatures T have been made as a function …

Mechanics Of Large Folds In Thin Interfacial Films, Vincent Demery, Benny Davidovitch, Christian D. Santangelo

Benny Davidovitch

A thin film at a liquid interface responds to uniaxial confinement by wrinkling and then by folding; its shape and energy have been computed exactly before self contact. Here, we address the mechanics of large folds, i.e. folds that absorb a length much larger than the wrinkle wavelength. With scaling arguments and numerical simulations, we show that the antisymmetric fold is energetically favorable and can absorb any excess length at zero pressure. Then, motivated by puzzles arising in the comparison of this simple model to experiments on lipid monolayers and capillary rafts, we discuss how to incorporate film weight, selfadhesion …

A Spitzer View Of The Giant Molecular Cloud Mon Ob1/Ngc 2264, Valerie A. Rapson, Judith L. Pipher, R. A. Gutermuth, Megeatj S. Thomas, Thomas S. Allen, Phillip C. Myers, Lori E. Allen

Robert A. Gutermuth

We present Spitzer 3.6, 4.5, 5.8, 8.0, and 24 μm images of the Mon OB1 East giant molecular cloud, which contains the young star forming region NGC 2264, as well as more extended star formation. With Spitzer data and Two Micron All Sky Survey photometry, we identify and classify young stellar objects (YSOs) with dusty circumstellar disks and/or envelopes in Mon OB1 East by their infrared-excess emission and study their distribution with respect to cloud material. We find a correlation between the local surface density of YSOs and column density of molecular gas as traced by dust extinction that is …

Preparing Climate Leaders: One Syllabus At A Time, Madeleine K. Charney

Madeleine K. Charney

Poster presentation at the 2014 Presidential Summit on Climate Leadership which highlighted the Sustainability Curriculum Initiative, a library-funded faculty mini-grant program that provides support for teaching sustainability courses across a wide range of disciplines. The poster illustrated the partnership between faculty members and subject specialist librarians. Also available was the Library’s Sustainability Research Guide, curriculum-building material which integrate library resources, photographs, and a White Paper outlining the history of the program. The Summit, held in Boston October 1-2, 2014 and hosted by Second Nature, was designed by Presidents for Presidents and Sustainability Staff in higher education. The focus of the …

A Mass Threshold In The Number Density Of Passive Galaxies At Z~2, V. Sommariva, A. Fontana, A. Lamastra, P. Santini, J.S. Dunlop, M. Castellano, H. Ferguson, R.J. Mclure, A. Galametz, Mauro Giavalisco, A Grazian, Y. Lu, N. Menci, A. Merson, D. Paris, L. Pentericci, R. Somerville, T. Targett

Mauro Giavalisco

The process that quenched star formation in galaxies at intermediate and high redshift is still the subject of considerable debate. One way to investigate this puzzling issue is to study the number density of quiescent galaxies at z ' 2, and its dependence on mass. Here we present the results of a new study based on very deep Ks-band imaging (with the HAWK-I instrument on the VLT) of two HST CANDELS fields (the UKIDSS Ultra-deep survey (UDS) field and GOODS-South). The new HAWK-I data (taken as part of the HUGS VLT Large Program) reach detection limits of Ks > 26 (AB …

Intellectual Property Cheat Sheet, Laura Quilter

Laura Quilter

A short table with an undergraduate-level overview of various forms of intellectual property in the United States. Provided for discussion in the Honors College Knowledge College seminar, Fall 2014.

From 'Banned In Boston' To Ethnic Studies In Arizona: Intellectual Freedom In America Today, Laura Quilter

Laura Quilter

This program will explore the meaning of Banned Books Week and what censorship means, as well as looking at what gets "banned" in America these days. Laura Quilter, a local librarian and information policy attorney, will lead a lively discussion of the law and politics of "banning books" -- from Comstockery through modern-day removal of identity studies curricula in Arizona and LGBT-themed children's books in public and school libraries.

Rapid Decline Of Lyman-Α Emission Toward The Reionization Era, V. Tilvi, C. Papovich, H.C. Ferguson, S.L. Finkelstein, J. Long, M. Song, M. Dickinson, A.M. Koekemoer, Mauro Giavalisco, B. Mobasher

Mauro Giavalisco

The observed deficit of strongly Lyman-α emitting galaxies at z > 6.5 is attributed to either increasing neutral hydrogen in the intergalactic medium (IGM) and/or to the evolving galaxy properties. To investigate this, we have performed very deep near-IR spectroscopy of z ≳7 galaxies using MOSFIRE on the Keck-I Telescope. We measure the Lyman-α fraction at z ∼ 8 using two methods. First, we derived NLy_/Ntot directly using extensive simulations to correct for incompleteness. Second, we used a Bayesian formalism (introduced by Treu et al. 2012) that compares the z > 7 galaxy spectra to models of the Lyman-α equivalent width (WLy_) …

Elegy For Allen, Prose/Poem 9/12/2014, Charles Smith

Charles Kay Smith

This Elegy is a poetic version of a eulogy I made at Allen Midyett's memorial service in late summer of 2013.

Fabrication Conditions For Efficient Organic Photovoltaic Cells From Aqueous Dispersions Of Nanoparticles, Monojit Bag, Timothy S. Gehan, Lawrence A. Renna, Dana D. Algaier, Paulm M. Lahti, Dhandapani Venkataraman

Dhandapani Venkataraman

For environmentally friendly and cost-effective manufacturing of organic photovoltaic (OPV) cells, it is highly desirable to replace haloarenes with water as the active layer fabrication solvent. Replacing an organic solvent with water requires retooling the device fabrication steps. The optimization studies were conducted using poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as active layer materials. These materials were dispersed in water as blend and separate nanoparticles using the miniemulsion method. Topologies of the active layers were investigated using atomic force microscopy and electron microscopy techniques. We have identified two essential steps to fabricate efficient OPVs from aqueous …

For Information On The Social Interaction And Culture Graduate Focus, Dept Of Communication, Click On "Download" Button, Benjamin Bailey

Benjamin Bailey

No abstract provided.

Kazhdan-Lusztig Cells In Planar Hyperbolic Coxeter Groups And Automata, Mikhail V. Belolipetsky, Paul E. Gunnells, Richard A. Scott

Paul Gunnells

Let C be a one- or two-sided Kazhdan–Lusztig cell in a Coxeter group (W, S), and let Red(C) be the set of reduced expressions of all w ∈ C, regarded as a language over the alphabet S. Casselman has conjectured that Red(C) is regular. In this paper, we give a conjectural description of the cells when W is the group corresponding to a hyperbolic polygon, and show that our conjectures imply Casselman's.

Roadmap To The Morphological Instabilities Of A Stretched Twisted Ribbon, Julien Chopin, Vincent Demery, Benny Davidovitch

Benny Davidovitch

We address the mechanics of an elastic ribbon subjected to twist and tensile load. Motivated by the classical work of green and a recent experiment that discovered a plethora of morphological instabilities, we introduce a comprehensive theoretical framework through which we construct a 4D phase diagram of this basic system, spanned by the exerted twist and tension as well as the thickness and length of the ribbon. Different types of instabilities appear in various "corners" of this 4D parameter space, and are addressed through distinct types of asymptotic methods. Our theory employs three instruments, whose concerted implementation is necessary to …