cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Effect of the Casimir energy on the bag model phenomenology of light hadrons
Creators: name: Bernotas, Andrius
name: Šimonis, Vytautas
Publisher: name: arXiv
Year: 2012
Subjects: subject: High Energy Physics - Phenomenology (hep-ph)
subject: FOS: Physical sciences

description: The dependence of light hadron masses and baryon magnetic moments on the magnitude of the Casimir energy is examined in the bag model with center-of-mass corrections. There are seven free parameters in the model. Six of them are determined from the fit to the masses of certain hadrons, and the last one (Casimir energy parameter) from the best fit to the magnetic moments of light baryons. The predicted magnetic moments are compared with the results obtained in various other models and with experiment data.
description: 23 pages, 4 figures and 7 tables
Colorado water, August/September 2007
Creators: name: Colorado Water Resources Research Institute, Author
Publisher: name: Mountain Scholar
Year: 2007
Subjects: subject: Water resources development -- Colorado
subject: Water use -- Colorado
subject: Water-supply -- Colorado
subject: Water-supply -- Management -- Colorado

description: The scope of the newsletter is devoted to enhancing communication between Colorado water users and managers and faculty at the research universities in the state.
description: Newsletter of the Water Center of Colorado State University.
Numerical Bifurcation Analysis of Conformal Formulations of the Einstein Constraints
Creators: name: Holst, M.
name: Kungurtsev, V.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Numerical Analysis (math.NA)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Mathematical Physics (math-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences

description: The Einstein constraint equations have been the subject of study for more than fifty years. The introduction of the conformal method in the 1970's as a parameterization of initial data for the Einstein equations led to increased interest in the development of a complete solution theory for the constraints, with the theory for constant mean curvature (CMC) spatial slices and closed manifolds completely developed by 1995. The first general non-CMC existence result was establish by Holst et al. in 2008, with extensions to rough data by Holst et al. in 2009, and to vacuum spacetimes by Maxwell in 2009. The non-CMC theory remains mostly open; moreover, recent work of Maxwell on specific symmetry models sheds light on fundamental non-uniqueness problems with the conformal method as a parameterization in non-CMC settings. In parallel with these mathematical developments, computational physicists have uncovered surprising behavior in numerical solutions to the extended conformal thin sandwich formulation of the Einstein constraints. In particular, numerical evidence suggests the existence of multiple solutions with a quadratic fold, and a recent analysis of a simplified model supports this conclusion. In this article, we examine this apparent bifurcation phenomena in a methodical way, using modern techniques in bifurcation theory and in numerical homotopy methods. We first review the evidence for the presence of bifurcation in the Hamiltonian constraint in the time-symmetric case. We give a brief introduction to the mathematical framework for analyzing bifurcation phenomena, and then develop the main ideas behind the construction of numerical homotopy, or path-following, methods in the analysis of bifurcation phenomena. We then apply the continuation software package AUTO to this problem, and verify the presence of the fold with homotopy-based numerical methods.
description: 13 pages, 4 figures. Final revision for publication, added material on physical implications
Catalytic applications of phosphorene: Computational design and experimental performance assessment
Creators: name: Nehra, Monika
name: Dilbaghi, Neeraj
name: Kumar, Rajesh
name: Srivastava, Sunita
name: Tankeshwar, K.
name: Kim, Ki-Hyun
name: Kumar, Sandeep
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Biophysics
subject: Biochemistry
subject: Molecular Biology
subject: Biotechnology
subject: Evolutionary Biology
subject: FOS: Biological sciences
subject: Chemical Sciences not elsewhere classified
subject: Biological Sciences not elsewhere classified
subject: Information Systems not elsewhere classified
subject: Hematology

description: In the current era, catalysts have gained intensive research interest in development of sustainable energy as well as environmental remediation. Recent exploration of novel two-dimensional (2D) materials can offer unparalleled superiorities in catalysis due to their novel geometric structure and electronic properties (e.g. intrinsically anisotropic electronic, thermoelectric, mechanical, and transport properties). Phosphorene, composed of a single atomic layer of black phosphorous, has emerged as a potential single elemental 2D material that bridges the gap between 2D metal chalcogenides and graphene in terms of physical properties. The puckered structure of phosphorene imparts great potential for their catalytic applications such as the generation and storage of clean energy (e.g. photovoltaic cells, supercapacitors, lithium-ion batteries, solar water splitting, and hydrogen/oxygen evolution reactions (HER/OER). In this review, an emphasis is placed on describing phosphorene in terms of its structural features (e.g. presence of defects) and catalytic properties along with synthesis strategies (e.g. liquid phase exfoliation, mechanical exfoliation, plasma exfoliation, and electrochemical exfoliation). This review is thus expected to provide comprehensive information on the current status of phosphorene as a catalyst (e.g. photocatalyst, electrocatalyst, and thermocatalyst) based on a combination of computational and experimental results.
Medical Cannabinoids as Treatment for Hypophosphatasia-Related Symptoms
Creators: name: Fischer, Jan Moritz
name: Jeitler, Michael
name: Blakeslee, Sarah Beverly
name: Kessler, Christian
Publisher: name: Charité - Universitätsmedizin Berlin
Year: 2022
Subjects: subject: cannabinoids
subject: chronic pain
subject: enzyme replacement therapy
subject: 600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit

description: Background: Hypophosphatasia (HPP) is a rare congenital disease caused by a mutation affecting tissue non-specific alkaline phosphatase, an enzyme involved in phosphate metabolism. The clinical manifestation usually includes bone-mineralization disorders, neurological symptoms, and persistent muscle pain.Case report: This case involves a woman in her sixties of Central European descent who suffers from life-long chronic pain and muscle weakness due to hypophosphatasia and concomitant degenerative changes of the lumbar spine. The patient is physically impaired and limited in her ability to walk as a result. HPP-specific and guideline-based multimodal pain management including enzyme replacement therapy with asfotase alfa, opioids, invasive orthopedic and neurosurgical procedures, long-term physiotherapy, and psychotherapy did not yield sufficient treatment results. The average pain was given as 8.5 on a numerical rating scale (NRS, 0-10) for the last 3 years. Treatment with a cannabidiol-predominant, full-spectrum, prescription cannabis extract led to a clinically meaningful pain reduction to 2.5/10 NRS, a discontinuation of opioids, and a recent resumption of employment as a physician.Conclusion: A more widespread consideration of medical cannabinoids in the treatment of complex chronic pain is proposed. Cannabinoids may pose a particularly potent treatment option for HPP-related symptoms and inflammation due to their known anti-inflammatory properties.
Stationary Distribution and Eigenvalues for a de Bruijn Process
Creators: name: Ayyer, Arvind
name: Strehl, Volker
Publisher: name: arXiv
Year: 2011
Subjects: subject: Probability (math.PR)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 60J27, 60C05, 05C50, 05C81, 82C20

description: We define a de Bruijn process with parameters n and L as a certain continuous-time Markov chain on the de Bruijn graph with words of length L over an n-letter alphabet as vertices. We determine explicitly its steady state distribution and its characteristic polynomial, which turns out to decompose into linear factors. In addition, we examine the stationary state of two specializations in detail. In the first one, the de Bruijn-Bernoulli process, this is a product measure. In the second one, the Skin-deep de Bruin process, the distribution has constant density but nontrivial correlation functions. The two point correlation function is determined using generating function techniques.
description: Dedicated to Herb Wilf on the occasion of his 80th birthday
Mitigating the Effect of Free-Riders in BitTorrent using Trusted Agents
Creators: name: Sherman, Alex
name: Stavrou, Angelos
name: Nieh, Jason
name: Stein, Clifford S.
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: Even though Peer-to-Peer (P2P) systems present a cost-effective and scalable solution to content distribution, most entertainment, media and software, content providers continue to rely on expensive, centralized solutions such as Content Delivery Networks. One of the main reasons is that the current P2P systems cannot guarantee reasonable performance as they depend on the willingness of users to contribute bandwidth. Moreover, even systems like BitTorrent, which employ a tit-for-tat protocol to encourage fair bandwidth exchange between users, are prone to free-riding (i.e. peers that do not upload). Our experiments on PlanetLab extend previous research (e.g. LargeViewExploit, BitTyrant) demonstrating that such selfish behavior can seriously degrade the performance of regular users in many more scenarios beyond simple free-riding: we observed an overhead of up to 430% for 80% of free-riding identities easily generated by a small set of selfish users. To mitigate the effects of selfish users, we propose a new P2P architecture that classifies peers with the help of a small number of {\em trusted nodes} that we call Trusted Auditors (TAs). TAs participate in P2P download like regular clients and detect free-riding identities by observing their neighbors' behavior. Using TAs, we can separate compliant users into a separate service pool resulting in better performance. Furthermore, we show that TAs are more effective ensuring the performance of the system than a mere increase in bandwidth capacity: for 80\% of free-riding identities a single-TA system has a 6\% download time overhead while without the TA and three times the bandwidth capacity we measure a 100\% overhead.
Rental Housing Assistance for the 21st Century
Creators: name: O'Flaherty, Brendan Andrew
Publisher: name: Columbia University
Year: 2011
Subjects: Economics
Low-income housing--Government policy
Low-income housing--Social aspects

description: Current rental housing assistance programs are not designed to provide a safety net for people whose lives are volatile, or to encourage poor people to live in good locations. These failings can be corrected. HUD should establish a program of rental insurance-like mortgage insurance, but for renters. Low income housing assistance formulas should be revised to reward good neighborhood features, and punish bad.
Preparation and Properties of Er-Doped ZrO2 Nanocrystalline Phase-Separated Preforms of Optical Fibers by MCVD Process
Creators: name: Dhar, Anirban
name: Kasik, Ivan
name: Podrazky, Ondrej
name: Matejec, Vlastimil
name: Dussardier, Bernard
Publisher: name: arXiv
Year: 2011
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: Optics (physics.optics)
subject: FOS: Physical sciences

description: The fabrication of Er-doped ZrO2-based nanocrystalline phase-separated silica optical preforms by the MCVD and solution doping techniques is presented. Fabricated preform cores are nearly transparent and contain phase-separated rare-earth doped nanocrystalline particles with diameters mainly in a range from 20 to 80 nm. High concentrations of erbium and aluminium in preform cores of about 0.3 and 14 mol%, respectively have been achieved without defects on the core-cladding interface. Spectral losses in a range 800-1600 nm and fluorescence spectra of erbium ions around 1550 nm measured on a fibre drawn from the preform are reported.
Investment from Russia stabilizes after the global crisis
Creators: name: Kuznetsov, Alexei
name: Chetverikova, Anna
name: Toganova, Natalia
Publisher: name: Columbia University
Year: 2011
Subjects: Business
Finance

description: The Institute of World Economy and International Relations (IMEMO) of the Russian Academy of Sciences, Moscow, and the Vale Columbia Center on Sustainable International Investment (VCC), a joint undertaking of the Columbia Law School and the Earth Institute at Columbia University in New York, are releasing the results of their second joint survey of Russian outward investors. The survey is part of a long-term study of the rapid global expansion of multinational enterprises (MNEs) from emerging markets. The present survey, conducted at the beginning of 2011, covers the period 2007-2009.
Struma ovarii with synchronous ascites and elevated CA125 level: a retrospective cohort study
Creators: name: Li, Sijian
name: Hong, Ruping
name: Yin, Min
name: Zhang, Xinyue
name: Zhang, Tianyu
name: Yang, Jiaxin
Publisher: name: Taylor & Francis
Year: 2023
Subjects: subject: Immunology
subject: FOS: Clinical medicine
subject: Cancer

description: Benign struma ovarii (SO) with synchronous ascites and elevated CA125 level is extremely rare that the incidence, clinical characteristics, and risk factors remain unclear. We conducted a retrospective study of patients with SO treated in our hospital between 1980 and 2022. Logistic regression was used to identify potential risk factors for SO patients presenting with ascites and elevated CA125 levels. The receiver operating characteristic (ROC) curve was used to evaluate the predictive performance of the identified risk factors. A total of 21 patients with synchronous ascites and elevated CA125 levels were identified in 229 patients with SO, the crude incidence rate was 9.17%, and four patients (1.75%) had pseudo-Meigs’ syndrome. Ascites were completely involuted within 1 month postoperatively and the serum CA125 level decreased to normal between 3 d and 6 weeks after surgery. Multivariate logistic regression showed that age ≥49 years (OR 3.71, 95% CI 1.29 − 10.64, p = 0.015), tumor size ≥10.0 cm (OR 8.79, 95% CI 3.05 − 25.35, p < 0.001), and proliferative SO (OR 11.16, 95% CI 3.01 − 41.47, p < 0.001) were the independent risk factors for patients presenting ascites and elevated CA 125 level. The ROC curve revealed that the predictive performance for age and tumor size was unsatisfactory with an area under the curve (AUC) was 0.646 and 0.682, respectively. Linear regression demonstrated that the serum CA125 level has a moderate positive correlation with the volume of ascites (log2CA125 = 0.6272*log2ascites + 2.099, p = 0.0001, R2 = 0.5576). Less than one-tenth of patients with SO would present ascites and elevated CA125 levels, while age ≥49 years, tumor sizes ≥10 cm, and the presence of proliferative SO were the risk factors.
Field Test of Classical Symmetric Encryption with Continuous Variable Quantum Key Distribution
Creators: name: Jouguet, Paul
name: Kunz-Jacques, Sébastien
name: Debuisschert, Thierry
name: Fossier, Simon
name: Diamanti, Eleni
name: Alléaume, Romain
name: Tualle-Brouri, Rosa
name: Grangier, Philippe
name: Leverrier, Anthony
name: Pache, Philippe
name: Painchault, Philippe
Publisher: name: arXiv
Year: 2012
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We report on the design and performance of a point-to-point classical symmetric encryption link with fast key renewal provided by a Continuous Variable Quantum Key Distribution (CVQKD) system. Our system was operational and able to encrypt point-to-point communications during more than six months, from the end of July 2010 until the beginning of February 2011. This field test was the first demonstration of the reliability of a CVQKD system over a long period of time in a server room environment. This strengthens the potential of CVQKD for information technology security infrastructure deployments.
Colorado water, August 1992
Creators: name: Miller, Shirley
name: Colorado Water Resources Research Institute, Publisher
Publisher: name: Mountain Scholar
Year: 1992
Subjects: subject: Water resources development -- Colorado
subject: Water-supply -- Colorado
subject: Water use -- Colorado
subject: Water-supply -- Management -- Colorado

description: The scope of the newsletter is devoted to enhancing communication between Colorado water users and managers and faculty at the research universities in the state.
description: Newsletter of the Colorado Water Resources Research Institute.
Whole Population, Genomewide Mapping of Hidden Relatedness
Creators: name: Gusev, Alexander
name: Lowe, Jennifer K.
name: Stoffel, Markus
name: Daly, Mark
name: Altshuler, David
name: Friedman, Jeffrey M.
name: Breslow, Jan L.
name: Pe'er, Itshack G.
Publisher: name: Columbia University
Year: 2008
Subjects: subject: Computer science
subject: Genetics
subject: FOS: Biological sciences

description: The ability to identify and quantify genealogical relationships between individuals within a population is an important step in accurately using such data for disease analysis and improving our understanding of demography. However, exhaustive pair-wise analysis which has been successful in small cohorts cannot keep up with the current torrent of genotype data. We present GERMLINE, a robust algorithm for identifying pairwise segmental sharing which scales linearly with the number of input individuals. Our approach is based on a dictionary of haplotypes, used to efficiently discover short exact matches between individuals and then expand these matches to identify long nearly-identical segmental sharing that is indicative of relatedness. We use GERMLINE to comprehensively survey hidden relatedness both in the HapMap as well as in a densely typed island population of 3,000 individuals. We verify that GERMLINE is in concordance with other methods when they can process the data, and also facilitates analysis of larger scale studies. We also demonstrate novel applications of precise analysis of hidden relatedness to detection of haplotype phasing errors and structural variation. We show that shared segment discovery can help identifying phasing errors and potentially resolve them. Finally, we use detected identity of genomic segments for exposing polymorphic deletions that are otherwise challenging to detect, with 8/14 deletions in the HapMap samples and 153/200 deletions in the island data having independent experimental validation.
The Binary Frequency of r-Process-Element Enhanced Metal-Poor Stars and its Implications: Chemical Tagging in the Primitive Halo of the Milky Way
Creators: name: Hansen, Terese
name: Andersen, Johannes
name: Nordström, Birgitta
name: Buchhave, Lars A.
name: Beers, Timothy C.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: A few rare halo giants in the range [Fe/H] $\simeq -2.9\pm0.3$ exhibit {\it r}-process element abundances that vary as a group by factors up to [$r$/Fe] $\sim80$, relative to those of the iron peak and below. Yet, the astrophysical production site of these {\it r}-process elements remains unclear. We report initial results from four years of monitoring the radial velocities of 17 {\it r}-process-enhanced metal-poor giants to detect and characterise binaries in this sample. We find three (possibly four) spectroscopic binaries with orbital periods and eccentricities that are indistinguishable from those of Population I binaries with giant primaries, and which exhibit no signs that the secondary components have passed through the AGB stage of evolution or exploded as supernovae. The other 14 stars in our sample appear to be single -- including the prototypical $r$-process-element enhanced star CS 22892-052, which is also enhanced in carbon, but not in {\it s}-process elements. We conclude that the {\it r}-process (and potentially carbon) enhancement of these stars was not a local event due to mass transfer or winds from a binary companion, but was imprinted on the natal molecular clouds of these (single and binary) stars by an external source. These stars are thus spectacular chemical tracers of the inhomogeneous nature of the early Galactic halo system.
Density Waves Excited by Low-Mass Planets in Protoplanetary Disks I: Linear Regime
Creators: name: Dong, Ruobing
name: Rafikov, Roman R.
name: Stone, James M.
name: Petrovich, Cristobal
Publisher: name: arXiv
Year: 2011
Subjects: subject: Earth and Planetary Astrophysics (astro-ph.EP)
subject: FOS: Physical sciences

description: Density waves excited by planets embedded in protoplanetary disks play a central role in planetary migration and gap opening processes. We carry out 2D shearing sheet simulations to study the linear regime of wave evolution with the grid-based code Athena, and provide detailed comparisons with the theoretical predictions. Low mass planets (down to ~0.03 Earth mass at 1 AU) and high spatial resolution (256 grid points per scale height) are chosen to mitigate the effects of wave nonlinearity. To complement the existing numerical studies, we focus on the primary physical variables such as the spatial profile of the wave, torque density, and the angular momentum flux carried by the wave, instead of secondary quantities such as the planetary migration rate. Our results show percent level agreement with theory in both physical and Fourier space. New phenomena such as the change of the toque density sign far from the planet are discovered and discussed. Also, we explore the effect of the numerical algorithms, and find that a high order of accuracy, high resolution, and an accurate planetary potential are crucial to achieve good agreement with the theory. We find that the use of a too large time-step without properly resolving the dynamical time scale around the planet produces incorrect results, and may lead to spurious gap opening. Global simulations of planet migration and gap opening violating this requirement may be affected by spurious effects resulting in e.g. the incorrect planetary migration rate and gap opening mass.
description: single column, 44 pages, 12 figures, ApJ in press, minor corrections made
Schema Polynomials and Applications
Creators: name: Ross, Kenneth A.
name: Stoyanovich, Julia
Publisher: name: Columbia University
Year: 2007
Subjects: Computer science

description: Conceptual complexity is emerging as a new bottleneck as database developers, application developers, and database administrators struggle to design and comprehend large, complex schemas. The simplicity and conciseness of a schema depends critically on the idioms available to express the schema. We propose a formal conceptual schema representation language that combines different design formalisms, and allows schema manipulation that exposes the strengths of each of these formalisms. We demonstrate how the schema factorization framework can be used to generate relational, object-oriented, and faceted physical schemas, allowing a wider exploration of physical schema alternatives than traditional methodologies. We illustrate the potential practical benefits of schema factorization by showing that simple heuristics can significantly reduce the size of a real-world schema description. We also propose the use of schema polynomials to model and derive alternative representations for complex relationships with constraints.
Two-dimensional simulations of nonlinear beam-plasma interaction in isotropic and magnetized plasmas
Creators: name: Timofeev, I. V.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Plasma Physics (physics.plasm-ph)
subject: FOS: Physical sciences

description: Nonlinear interaction of a low density electron beam with a uniform plasma is studied using two-dimensional particle-in-cell (PIC) simulations. We focus on formation of coherent phase space structures in the case, when a wide two-dimensional wave spectrum is driven unstable, and we also study how nonlinear evolution of these structures is affected by the external magnetic field. In the case of isotropic plasma, nonlinear buildup of filamentation modes due to the combined effects of two-stream and oblique instabilities is found to exist and growth mechanisms of secondary instabilities destroying the BGK--type nonlinear wave are identified. In the weak magnetic field, the energy of beam-excited plasma waves at the nonlinear stage of beam-plasma interaction goes predominantly to the short-wavelength upper-hybrid waves propagating parallel to the magnetic field, whereas in the strong magnetic field the spectral energy is transferred to the electrostatic whistlers with oblique propagation.
Experimental results in the CK format (GCC and LLVM compiler flag crowd-tuning)
Creators: name: Fursin, Grigori
Publisher: name: Zenodo
Year: 2019
Subjects: collective knowledge
compiler crowd-tuning
compiler autotuning
crowdsourcing experiments
open science
collaborative research

description: Experimental results in the open Collective Knowledge format for GCC and LLVM compiler flags autotuning crowdsourced across diverse Android devices provided by volunteers:

	Interactive paper automatically generated via CK
	ArXiv paper
	Android app
	Public dashboard for GCC
	Public dashboard for LLVM

You can install those results in your local CK repository as follows:

ck pull repo:ck-crowdtuning

ck unzip repo --zip=ckr-upload-gcc-llvm-flags.20190201.zip

description: {"references": ["Fursin, Grigori et.al. A Collective Knowledge workflow for collaborative research into multi-objective autotuning and machine learning techniques. arXiv:1801.08024."]}
VoIP-based Air Traffic Controller Training
Creators: name: Subramanya, Supreeth
name: Wu, Xiaotao
name: Schulzrinne, Henning G.
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: Extending VoIP beyond the Internet telephony, we propose a case study of applying the technology outside of its intended domain, to solve a real-world problem. This work is an attempt to understand an analog hardwired communication system of the U.S. Federal Aviation Administration (FAA), and effectively translate it into a generic, standards-based VoIP system that runs on their existing data network. We develop insights into the air traffic training and weigh on the design choices for building a soft real-time data communication system. We also share our real-world deployment and maintenance experiences, as the FAA Academy has been successfully using this VoIP system in five training rooms since 2006 to train the future air traffic controllers of the U.S. and the world.
Tractability of multivariate approximation over a weighted unanchored Sobolev space: Smoothness sometimes hurts
Creators: name: Werschulz, Arthur G.
name: Wozniakowski, Henryk
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: We study d-variate approximation for a weighted unanchored Sobolev space having smoothness m ≥ 1. Folk wisdom would lead us to believe that this problem should become easier as its smoothness increases. This is true if we are only concerned with asymptotic analysis: the nth minimal error is of order n^-(m-δ) for any δ > 0. However, it is unclear how long we need to wait before this asymptotic behavior kicks in. How does this waiting period depend on d and m? We prove that no matter how the weights are chosen, the waiting period is at least m^d, even if the error demand ε is arbitrarily close to 1. Hence, for m ≥ 2, this waiting period is exponential in d, so that the problem suffers from the curse of dimensionality and is intractable. In other words, the fact that the asymptotic behavior improves with m is irrelevant when d is large. So, we will be unable to vanquish the curse of dimensionality unless m = 1 , i.e., unless the smoothness is minimal. We then show that our problem can be tractable if m = 1. That is, we can find an ε-approximation using polynomially-many (in d and ε^-1) information operations, even if only function values are permitted. When m = 1, it is even possible for the problem to be strongly tractable, i.e., we can find an ε-approximation using polynomially-many (in ε^-1) information operations, independent of d. These positive results hold when the weights of the Sobolev space decay sufficiently quickly or are bounded finite-order weights, i.e., the d-variate functions we wish to approximate can be decomposed as sums of functions depending on at most ω variables, where ω is independent of d.
Experiences in Teaching eXtreme Programming in a Distance Learning Program
Creators: name: Murphy, Christian
name: Phung, Dan
name: Kaiser, Gail E.
Publisher: name: Columbia University
Year: 2007
Subjects: Computer science

description: As university-level distance learning programs become more and more popular, and software engineering courses incorporate eXtreme Programming (XP) into their curricula, certain challenges arise when teaching XP to students who are not physically co-located. In this paper, we present our experiences and observations from managing such an online software engineering course, and describe some of the specific challenges we faced, such as students' aversion to using XP and difficulties in scheduling. We also present some suggestions to other educators who may face similar situations.
Improving Virtual Appliances through Virtual Layered File Systems
Creators: name: Potter, Shaya
name: Nieh, Jason
Publisher: name: Columbia University
Year: 2007
Subjects: Computer science

description: The problem of managing computers is growing in complexity due to the increasing amount of physical and virtual computers that one has to administer as well as the varying roles that those computers fill. As each machine is effectively fully independent, the amount of work an administrator does scales linearly with the amount of machines. In order to solve this problem, we introduce Strata, a system that enables new ways of managing these many distinct installations. Strata enables many systems to be easily managed by introducing a virtual layered file system that composes individual software layers together into a single file system view. By providing the ability to share layers between installations, Strata eases the creation of independent systems and opens up new ways to use computers. We have implemented Strata on Linux without requiring any application or operating system kernel changes. Our measurements on real world applications demonstrate that Strata imposes little overhead.
Thermoelectric transport of mesoscopic conductors coupled to voltage and thermal probes
Creators: name: Sanchez, David
name: Serra, Llorens
Publisher: name: arXiv
Year: 2011
Subjects: subject: Mesoscale and Nanoscale Physics (cond-mat.mes-hall)
subject: FOS: Physical sciences

description: We investigate basic properties of the thermopower (Seebeck coefficient) of phase-coherent conductors under the influence of dephasing and inelastic processes. Transport across the system is caused by a voltage bias or a thermal gradient applied between two terminals. Inelastic scattering is modeled with the aid of an additional probe acting as an ideal potentiometer and thermometer. We find that inelastic scattering reduces the conductor's thermopower and, more unexpectedly, generates a magnetic-field asymmetry in the Seebeck coefficient. The latter effect is shown to be a higher-order effect in the Sommerfeld expansion. We discuss our result using two illustrative examples. First, we consider a generic mesoscopic system described within random matrix theory and demonstrate that thermopower fluctuations disappear quickly as the number of probe modes increases. Second, the asymmetry is explicitly calculated in the quantum limit of a ballistic microjunction. We find that asymmetric scattering strongly enhances the effect and discuss its dependence on temperature and Fermi energy.
description: 4+ pages, 2 figures and supplementary material. Published version
Chinese multinationals gain further momentum
Creators: name: Zhu, Qiuzhi
name: Zhu, Lijia
name: Zhou, Jun
Publisher: name: Columbia University
Year: 2010
Subjects: Business
Finance

description: The third annual survey of the leading Chinese multinationals, conducted by the School of Management at Fudan University and the Vale Columbia Center on Sustainable International Investment (VCC) at Columbia University in New York, released its results, indicating that Chinese multinationals are gaining strong growth momentum on the world stage. The survey was conducted in 2010 and covered the year 2008.
Colorado water, February 1995
Creators: name: Brady, Cindy
name: Eyre, Julie
name: Marsh, Jill
name: Klein, Kathleen
name: Williams, David
name: Miller, Shirley
name: Colorado Water Resources Research Institute, Publisher
Publisher: name: Mountain Scholar
Year: 1995
Subjects: subject: Water resources development -- Colorado
subject: Water use -- Colorado
subject: Water-supply -- Colorado
subject: Water-supply -- Management -- Colorado

description: The scope of the newsletter is devoted to enhancing communication between Colorado water users and managers and faculty at the research universities in the state.
description: Newsletter of the Colorado Water Resources Research Institute.
Phishing - A Growing Threat to E-Commerce
Creators: name: Banday, M. Tariq
name: Qadri, Jameel A.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Cryptography and Security (cs.CR)
subject: FOS: Computer and information sciences
subject: K.4.4; K.6.5; D.4.6; K.4.2

description: In today's business environment, it is difficult to imagine a workplace without access to the web, yet a variety of email born viruses, spyware, adware, Trojan horses, phishing attacks, directory harvest attacks, DoS attacks, and other threats combine to attack businesses and customers. This paper is an attempt to review phishing - a constantly growing and evolving threat to Internet based commercial transactions. Various phishing approaches that include vishing, spear phishng, pharming, keyloggers, malware, web Trojans, and others will be discussed. This paper also highlights the latest phishing analysis made by Anti-Phishing Working Group (APWG) and Korean Internet Security Center.
description: 8 Pages
Trade-offs in Private Search
Creators: name: Pappas, Vasileios
name: Raykova, Mariana Petrova
name: Vo, Binh D.
name: Bellovin, Steven Michael
name: Malkin, Tal G.
Publisher: name: Columbia University
Year: 2010
Subjects: Computer science

description: Encrypted search -- performing queries on protected data -- is a well researched problem. However, existing solutions have inherent inefficiency that raises questions of practicality. Here, we step back from the goal of achieving maximal privacy guarantees in an encrypted search scenario to consider efficiency as a priority. We propose a privacy framework for search that allows tuning and optimization of the trade-offs between privacy and efficiency. As an instantiation of the privacy framework we introduce a tunable search system based on the SADS scheme and provide detailed measurements demonstrating the trade-offs of the constructed system. We also analyze other existing encrypted search schemes with respect to this framework. We further propose a protocol that addresses the challenge of document content retrieval in a search setting with relaxed privacy requirements.
The European Union at Copenhagen : actorness, leadership and the international climate change regime
Creators: name: Mcilwain, John Robertson
Publisher: name: University of British Columbia
Year: 2011

description: The European Union has gained a reputation in recent years as a ʻgreenʼ leader, especially within the UNFCCC. That reputation perhaps amplified the perceived failure that occurred at the 15th Conference of Parties in December 2009 in Copenhagen. Why was Copenhagen such a disappointment? The post-modern character of the European Union—as a polity somewhere between a federal state and a international organization —has often made it difficult for the organization to take on a leadership role, nay operate, within the traditional international relations structure. The reasons for the EUʼs recent difficulty within the climate change regime may reside with two factors. First, an undeveloped sense of ʻactornessʼ on the part of the EU and, second, systemic problems within the regime itself. Here we analyze what happened at the Conference by looking at the development of the EUʼs role and polices within the climate change regime
Field-induced criticality in a gapped quantum magnet with bond disorder
Creators: name: Hüvonen, D.
name: Zhao, S.
name: Månsson, M.
name: Yankova, T.
name: Ressouche, E.
name: Niedermayer, C.
name: Laver, M.
name: Gvasaliya, S. N.
name: Zheludev, A.
Publisher: name: arXiv
Year: 2012
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: FOS: Physical sciences

description: Neutron diffraction and calorimetric measurements are used to study the field-induced quantum phase transition in piperazinium-Cu$_2$(Cl$_{1-x}$Br$_x$)$_6$ ($x=0$, x=3.5% and x=7.5%), a prototypical quantum antiferromagnet with random bonds. The critical indexes $ϕ$ and $β$ are determined. The findings contradict some original predictions for Bose Glass based on the assumption $z=d$, but are consistent with recent theoretical results implying $z
description: 4.2 pages, 4 figures. Submitted to PRB Rapid Communications
The Galactic thin and thick disk
Creators: name: Steinmetz, Matthias
Publisher: name: arXiv
Year: 2012
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: The ongoing large spectroscopic surveys of the Milky Way such as SEGUE and RAVE have enabled us to take a fresh look at the structure of the Galactic thin and thick disks, and how their structure fits within the framework of structure formation via hierarchical clustering. In this article I will summarize some recent results mainly based in the RAVE survey with respect to the structure of the Galactic disks, their possible origin as well as indications of substructure and asymmetries.
description: Invited review given at the Annual Meeting of the German Astronomical Society, Heidelberg, Sept 19-23, 2011
An Approach to Software Testing of Machine Learning Applications
Creators: name: Murphy, Christian
name: Kaiser, Gail E.
name: Arias, Marta
Publisher: name: Columbia University
Year: 2007
Subjects: Computer science

description: Some machine learning applications are intended to learn properties of data sets where the correct answers are not already known to human users. It is challenging to test such ML software, because there is no reliable test oracle. We describe a software testing approach aimed at addressing this problem. We present our findings from testing implementations of two different ML ranking algorithms: Support Vector Machines and MartiRank.
Can P2P Replace Direct Download for Content Distribution
Creators: name: Sherman, Alex
name: Stavrou, Angelos
name: Nieh, Jason
name: Stein, Clifford S.
name: Keromytis, Angelos D.
Publisher: name: Columbia University
Year: 2007
Subjects: Computer science

description: While peer-to-peer (P2P) file-sharing is a powerful and cost-effective content distribution model, most paid-for digital-content providers (CPs) rely on direct download to deliver their content. CPs such as Apple iTunes that command a large base of paying users are hesitant to use a P2P model that could easily degrade their user base into yet another free file-sharing community. We present TP2, a system that makes P2P file sharing a viable delivery mechanism for paid digital content by providing the same security properties as the currently used direct-download model.} introduces the novel notion of trusted auditors (TAs) -- P2P peers that are controlled by the system operator. TAs monitor the behavior of other peers and help detect and prevent formation of illegal file-sharing clusters among the CP's user base. TAs both complement and exploit the strong authentication and authorization mechanisms that are used in TP2 to control access to content. It is important to note that TP2 does not attempt to solve the out-of-band file-sharing or DRM problems, which also exist in the direct-download systems currently in use. We analyze TP2 by modeling it as a novel game between misbehaving users who try to form unauthorized file-sharing clusters and TAs who curb the growth of such clusters. Our analysis shows that a small fraction of TAs is sufficient to protect the P2P system against unauthorized file sharing. In a system with as many as 60\% of misbehaving users, even a small fraction of TAs can detect 99\% of unauthorized cluster formation. We developed a simple economic model to show that even with such a large fraction of malicious nodes, TP2 can improve CP's profits (which could translate to user savings) by 62 to 122\%, even while assuming conservative estimates of content and bandwidth costs. We implemented TP2 as a layer on top of BitTorrent and demonstrated experimentally using PlanetLab that our system provides trusted P2P file sharing with negligible performance overhead.
Colorado water, February 2002
Creators: name: Flanagan, Marian
name: Blackledge, Michael
name: Miller, Shirley
name: Colorado Water Resources Research Institute, Publisher
Publisher: name: Mountain Scholar
Year: 2002
Subjects: subject: Water resources development -- Colorado
subject: Water use -- Colorado
subject: Water-supply -- Colorado
subject: Water-supply -- Management -- Colorado

description: The scope of the newsletter is devoted to enhancing communication between Colorado water users and managers and faculty at the research universities in the state.
description: Newsletter of the Water Center at Colorado State University.
Observation of the Thermal Casimir Force is Open to Question
Creators: name: Klimchitskaya, G. L.
name: Bordag, M.
name: Fischbach, E.
name: Krause, D.
name: Mostepanenko, V. M.
Publisher: name: arXiv
Year: 2011
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We discuss theoretical predictions for the thermal Casimir force and compare them with available experimental data. Special attention is paid to the recent claim of the observation of that effect, as predicted by the Drude model approach. We show that this claim is in contradiction with a number of experiments reported so far. We suggest that the experimental errors, as reported in support of the observation of the thermal Casimir force, are significantly underestimated. Furthermore, the experimental data at separations above $3\,μ$m are shown to be in agreement not with the Drude model approach, as is claimed, but with the plasma model. The seeming agreement of the data with the Drude model at separations below $3\,μ$m is explained by the use of an inadequate formulation of the proximity force approximation.
description: 12 pages, 4 figures, to appear in Int. J. Mod. Phys. A
Matching with a Handicap: The Case of Smoking in the Marriage Market
Creators: name: Chiappori, Pierre A.
name: Oreffice, Sonia
name: Quintana-Domeque, Climent
Publisher: name: Columbia University
Year: 2011
Subjects: Economics
Social sciences--Research

description: We develop a matching model on the marriage market, where individuals have preferences over the smoking status of potential mates, and over their socioeconomic quality. Spousal smoking is bad for non-smokers, but it is neutral for smokers, while individuals always prefer high socioeconomic quality. Furthermore, there is a gender difference in smoking prevalence, there being more smoking men than smoking women for all education levels, so that smoking women and non-smoking men are in short supply. The model generates clear cut conditions regarding matching patterns. Using CPS data and its Tobacco Use Supplements for the years 1996 to 2007, and proxing socioeconomic status by educational attainment, we .nd that these conditions are satis.ed. There are fewer "mixed" couples where the wife smokes than vice-versa, and matching is assortative on education within smoking types of couples. Among non-smoking wives those with smoking husbands have on average 0.14 fewer years of completed education than those with non-smoking husbands. Finally, and somewhat counterintuitively, we find that, as theory predicts, among smoking husbands those who marry smoking wives have on average 0.16 more years of completed education than those with non-smoking wives.
The Tradeoffs of Societal Computing
Creators: name: Sheth, Swapneel Kalpesh
name: Kaiser, Gail E.
Publisher: name: Columbia University
Year: 2010
Subjects: Computer science

description: As Social Computing has increasingly captivated the general public, it has become a popular research area for computer scientists. Social Computing research focuses on online social behavior and using artifacts derived from it for providing recommendations and other useful community knowledge. Unfortunately, some of that behavior and knowledge incur societal costs, particularly with regards to Privacy, which is viewed quite differently by different populations as well as regulated differently in different locales. But clever technical solutions to those challenges may impose additional societal costs, e.g., by consuming substantial resources at odds with Green Computing, another major area of societal concern. We propose a new crosscutting research area, Societal Computing, that focuses on the technical tradeoffs among computational models and application domains that raise significant societal issues. We highlight some of the relevant research topics and open problems that we foresee in Societal Computing where software engineering research approaches and techniques seem particularly likely to be fruitful. We feel that these topics, and Societal Computing in general, need to gain prominence as they will provide useful avenues of research leading to increasing benefits for society as a whole.
Measurements of Multicast Service Discovery in a Campus
Creators: name: Hong, Se Gi
name: Srinivasan, Suman Ramkumar
name: Schulzrinne, Henning G.
Publisher: name: Columbia University
Year: 2008
Subjects: Computer science

description: Applications utilizing multicast service discovery protocols, such as iTunes, have become increasingly popular. However, multicast service discovery protocols are considered to generate network traffic overhead, especially in a wireless network. Therefore, it becomes important to evaluate the traffic and overhead caused by multicast service discovery packets in real-world networks. We measure and analyze the traffic of one of the mostly deployed multicast service discovery protocols, multicast DNS (mDNS) service discovery, in a campus wireless network that forms a single multicast domain of large users. We also analyze different service discovery models in terms of packet overhead and service discovery delay under different network sizes and churn rates. Our measurement shows that mDNS traffic consumes about 13 percent of the total bandwidth.