cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Nonconvex penalization of switching control of partial differential equations
Creators: name: Clason, Christian
name: Rund, Armin
name: Kunisch, Karl
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optimization and Control (math.OC)
subject: FOS: Mathematics

description: This paper is concerned with optimal control problems for parabolic partial differential equations with pointwise in time switching constraints on the control. A standard approach to treat constraints in nonlinear optimization is penalization, in particular using $L^1$-type norms. Applying this approach to the switching constraint leads to a nonsmooth and nonconvex infinite-dimensional minimization problem which is challenging both analytically and numerically. Adding $H^1$ regularization or restricting to a finite-dimensional control space allows showing existence of optimal controls. First-order necessary optimality conditions are then derived using tools of nonsmooth analysis. Their solution can be computed using a combination of Moreau-Yosida regularization and a semismooth Newton method. Numerical examples illustrate the properties of this approach.
Achieving the Dispatchability of Distribution Feeders through Prosumers Data Driven Forecasting and Model Predictive Control of Electrochemical Storage
Creators: name: Sossan, Fabrizio
name: Namor, Emil
name: Cherkaoui, Rachid
name: Paolone, Mario
Publisher: name: arXiv
Year: 2016
Subjects: subject: Systems and Control (eess.SY)
subject: FOS: Electrical engineering, electronic engineering, information engineering

description: We propose and experimentally validate a control strategy to dispatch the operation of a distribution feeder interfacing heterogeneous prosumers by using a grid-connected battery energy storage system (BESS) as a controllable element coupled with a minimally invasive monitoring infrastructure. It consists in a two-stage procedure: day-ahead dispatch planning, where the feeder 5-minute average power consumption trajectory for the next day of operation (called \emph{dispatch plan}) is determined, and intra-day/real-time operation, where the mismatch with respect to the \emph{dispatch plan} is corrected by applying receding horizon model predictive control (MPC) to decide the BESS charging/discharging profile while accounting for operational constraints. The consumption forecast necessary to compute the \emph{dispatch plan} and the battery model for the MPC algorithm are built by applying adaptive data driven methodologies. The discussed control framework currently operates on a daily basis to dispatch the operation of a 20~kV feeder of the EPFL university campus using a 750~kW/500~kWh lithium titanate BESS.
description: Submitted for publication, 2016
RELATIONSHIPS BETWEEN LOWER EXTREMITY MOVEMENT QUALITY, INTERNAL TRAINING LOADS, AND INJURY RISK IN NCAA DIVISION I MALE COLLEGIATE SOCCER ATHLETES
Creators: name: Condon, Tara
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2018

description: The purpose of this study was to examine the relationships amongst internal training loads (ITL), lower extremity (LE) movement quality, and injury risk in male collegiate soccer athletes. Fifty-two Division-I athletes consented to this study. Daily ITL were collected and tracked over the course of two consecutive seasons using a rated perceived exertion scale and session duration. LE movement assessments were performed in preseason using the Landing Error Scoring system (LESS), and were used to create two groups: poor movers (n=33,LESS ≥5), and good movers (n=19,LESS ≤4). Repeated measures ANOVAs and Chi Squares were utilized for analysis. Mid-season ITL were significantly lower compared to early (p<.001) and late (p<.001) season ITL. No significant differences in ITL were found between poor and good movers. Early-season injury risk was not influenced by movement quality or ITL but future large sample studies are needed in NCAA collegiate athletes.
S-duality wall of SQCD from Toda braiding
Creators: name: Floch, Bruno Le
Publisher: name: arXiv
Year: 2015
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: Exact field theory dualities can be implemented by duality domain walls such that passing any operator through the interface maps it to the dual operator. This paper describes the S-duality wall of four-dimensional ${\cal N}=2$ SU(N) SQCD with 2N hypermultiplets in terms of fields on the defect, namely three-dimensional ${\cal N}=2$ SQCD with gauge group U(N-1) and 2N flavours, with a monopole superpotential. The theory is self-dual under a duality found by Benini, Benvenuti and Pasquetti, in the same way that T[SU(N)] (the S-duality wall of ${\cal N}=4$ super Yang-Mills) is self-mirror. The domain-wall theory can also be realized as a limit of a USp(2N-2) gauge theory; it reduces to known results for N=2. The theory is found through the AGT correspondence by determining the braiding kernel of two semi-degenerate vertex operators in Toda CFT.
description: v2: correct superpotential to fix symmetries, better introduction and references, 42 pages
Global rates of convergence for nonconvex optimization on manifolds
Creators: name: Boumal, Nicolas
name: Absil, P. -A.
name: Cartis, Coralia
Publisher: name: arXiv
Year: 2016
Subjects: subject: Optimization and Control (math.OC)
subject: Numerical Analysis (math.NA)
subject: FOS: Mathematics

description: We consider the minimization of a cost function $f$ on a manifold $M$ using Riemannian gradient descent and Riemannian trust regions (RTR). We focus on satisfying necessary optimality conditions within a tolerance $\varepsilon$. Specifically, we show that, under Lipschitz-type assumptions on the pullbacks of $f$ to the tangent spaces of $M$, both of these algorithms produce points with Riemannian gradient smaller than $\varepsilon$ in $O(1/\varepsilon^2)$ iterations. Furthermore, RTR returns a point where also the Riemannian Hessian's least eigenvalue is larger than $-\varepsilon$ in $O(1/\varepsilon^3)$ iterations. There are no assumptions on initialization. The rates match their (sharp) unconstrained counterparts as a function of the accuracy $\varepsilon$ (up to constants) and hence are sharp in that sense. These are the first deterministic results for global rates of convergence to approximate first- and second-order Karush-Kuhn-Tucker points on manifolds. They apply in particular for optimization constrained to compact submanifolds of $\mathbb{R}^n$, under simpler assumptions.
description: 33 pages, IMA Journal of Numerical Analysis, 2018
Biological and Chemoenzymatic Synthesis of Anticoagulant Heparan Sulfate
Creators: name: Duncan, Michael Bernard
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: Heparan sulfate (HS) is a linear, heterogeneously sulfated polysaccharide that is ubiquitous to most mammalian tissues. The roles played by HS on the cell surface and in the extracellular matrix (ECM) are diverse in function. A number of HS/protein interactions have been studied and have led to a more detailed understanding of signal transduction pathways, enzyme activation, and ligand presentation. Accumulating evidence has supported the role of the fine structure of HS in high-affinity interactions with serine protease inhibitors, growth factors, and microbial coat proteins. These findings have led to a great deal of interest in understanding how specific HS structures are generated and the mechanisms that regulate HS biosynthesis. Complex HS sequences are generated by a number of biosynthetic enzyme families, including the N-deacteylase N-sulfotransferases, epimerase, 2-O-, 6-O-, and 3-Osulfotransferases. Herein, studies are presented that explore the functions of N-deacetylase N-sulfotransferase and the 3-O-sulfotransferases. In addition, we report a chemoenzymatic approach to synthesizing anticoagulant heparin, a structural analogue of HS. The anticoagulant effects of heparin, derived from natural sources, have been exploited in the clinic for over seventy years. A synthetic approach to heparin production could provide the anticoagulant with reduced side effects. It would also allow for the investigation of other therapeutic benefits of heparin and HS. In conclusion, the work presented herein provides detail into the biosynthetic machinery and biological properties of HS, as well as strategies to control the assembly of heparin and HS polysaccharides.
The Series Product for Gaussian Quantum Input Processes
Creators: name: Gough, John E.
name: James, Matthew R.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: We present the theory for connecting quantum Markov components into a network with quantum input processes in a Gaussian state (including thermal and squeezed), not necessarily vacuum fields.One would expect on physical grounds that the connection rules should be independent of the state of the input to the network. To compute statistical properties, we use a version of Wicks' Theorem involving fictitious vacuum fields (Fock space based representation of the fields) and while this aids computation, and gives a rigorous formulation, the various representations need not be unitarily equivalent. In particular, a naive application of the connection rules would lead to the wrong answer. We establish the correct interconnection rules, and show that while the quantum stochastic differential equations of motion display explicitly the covariances (thermal and squeezing parameters) of the Gaussian input fields We introduce the Wick-Stratonovich form which leads to a way of writing these equations that does not depend on these covariances and so corresponds to the universal equations written in terms of formal quantum input processes. We show that a wholly consistent theory of quantum open systems in series can be developed in this way, and as required physically, is universal and in particular representation-free.
description: 24 pages, 0 figures (Condensed version - V1 still useful as a comprehensive preprint)
A New Reading of Caffaro
Creators: name: Morgan, Daniel
Publisher: name: University of North Carolina at Chapel Hill Graduate School
Year: 2015
Subjects: History
Middle Ages

description: This thesis analyzes the narrative structure and tropes of the De liberatione civitatum orientis by Caffaro di Rustico da Caschifellone. The goal of this project is threefold: first, to provide a closer reading of Caffaro's text than has previously been offered; second, to critique an historiographical paradigm that ineffectually categorizes and mediates narrative source materials for the First Crusade; and third, to gesture towards a potential methodological solution offered by the tools of narratology and the theoretical language of the linguistic turn. Through a consideration of how key narratological elements in this text functioned to create meaning, Caffaro's text is then placed in conversation with other First Crusade sources. A fuller understanding of Caffaro's narrative is possible only when it is considered alongside these other sources and as part of a larger crusade metanarrative.
BCS theory with the external pair potential
Creators: name: Grigorishin, Konstantin V.
Publisher: name: arXiv
Year: 2016
Subjects: subject: Superconductivity (cond-mat.supr-con)
subject: FOS: Physical sciences

description: We consider a hypothetical substance, where interaction between (within) structural elements of condensed matter (molecules, nanoparticles, clusters, layers, wires etc.) depends on state of Cooper pairs: an additional work must be made against this interaction to break a pair. Such a system can be described by BCS Hamiltonian with the external pair potential term. In this model the potential essentially renormalizes the order parameter: if the pairing lowers energy of the structure the energy gap is slightly enlarged at zero temperature and asymptotically tends to zero as temperature rises. Thus the critical temperature of such a superconductor is equal to infinity formally. For this case the effective Ginzburg-Landau theory is formulated, where the coherence length decreases as temperature rises, the GL parameter and the second critical field are increasing functions of temperature unlike the standard theory. If the pairing enlarges energy of the structure then suppression of superconductivity and the first order phase transition occur.
description: 18 pages, 10 figures
Absorption of the Lyman-$α$ radiation in the heliosphere
Creators: name: Kowalska-Leszczynska, Izabela
name: Kubiak, Marzena A.
name: Bzowski, Maciej
Publisher: name: arXiv
Year: 2021
Subjects: subject: Solar and Stellar Astrophysics (astro-ph.SR)
subject: Space Physics (physics.space-ph)
subject: FOS: Physical sciences

description: Absorption of the Lyman-$α$ radiation on Interstellar Neutral Hydrogen (ISN H) atoms in the heliosphere is a potentially important effect to account for in precise gas distribution simulations. In this paper we develop a method to estimate the magnitude of absorption of solar Lyman-$α$ radiation inside the solar wind termination shock and to include absorption effects in the Warsaw Test Particle Model (WTPM) by an appropriate modification of radiation pressure. We perform calculations of absorption effects on a 3D grid in the heliosphere and present a set of parameters to model absorption effects for the mean solar activity conditions. We show that absorption can change up to 3% depending on the solar activity level. Using a modified version of WTPM, we calculate the expected signal from IBEX-Lo and show that absorption may modify the simulated flux up to 8%.
description: Submited to ApJ
The U.S. Farmer in the International Food Situation
Creators: name: West, Quentin M.
name: West, Quentin M.
Publisher: name: Unknown
Year: 1977
Subjects: Agricultural and Food Policy
Crop Production/Industries
Demand and Price Analysis
International Relations/Trade
Livestock Production/Industries
Risk and Uncertainty

description: Excerpts from the report: Farmers across this Nation have seen terrific change over the past several years both in their fortunes and in the role they play in the international food situation. U.S. agriculture has moved from limited production to full production, from reliance on price supports to a market price orientation, from large government stocks to virtually none, and toward a free market for farm goods—with no more embargoes. With this new independence for the U.S. farmer has come a new interdependence. Never before has the fate of a farmer in the steppes of Russia been tied so closely to the fortune of a farmer in the Great Plains of the United States. For the short term, at least, this interdependence with the course of agriculture and food supplies elsewhere in the world spells uncertainty for farmers here. The government has withdrawn its controls over the agricultural marketplace, and farmers have generally applauded that change. But tradeoffs are involved. One is the uncertainty that that withdrawal implies. Tradeoffs like this one—between freedom and uncertainty for farmers in the marketplace will be weighed in this year's debate on new farm legislation, as the course of future government programs for agriculture is decided.
Conceivable Commission of War Crime in Afghanistan
Creators: name: Wasiq, Mohammad Rasikh
Publisher: name: figshare
Year: 2023
Subjects: Conflict of laws (incl. private international law)
Legal practice, lawyering and the legal profession
International criminal law
Constitutional law
Law and society and socio-legal research
Public law not elsewhere classified
Law in context not elsewhere classified
Law and humanities
European Union law
Criminal law
Public international law
Asian and Pacific law
Military law and justice
International humanitarian and human rights law

description: When armies are engaged in combat, war crimes are defined as violations of the law of war. It is a broad conception, and any harm done to humanity in a time of peace is viewed as a war crime. War crimes include any form of human rights violation. For a few decades, the suffering of Afghans was overlooked by the outside world, but it is now unacceptable that Afghanistan's leadership is following suit. There is no comprehensive genocide law in Afghanistan. War crimes in Afghanistan included things like mistreating civilians or POWs. The issue of genocide and associated violence must be addressed. As a result, war crimes in Afghanistan constitute transgressions of international humanitarian law, which carry with them a personal liability and must be thoroughly investigated.
Quasi-classical expansion of the star-triangle relation and integrable systems on quad-graphs
Creators: name: Bazhanov, Vladimir V.
name: Kels, Andrew P.
name: Sergeev, Sergey M
Publisher: name: arXiv
Year: 2016
Subjects: subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: In this paper we give an overview of exactly solved edge-interaction models, where the spins are placed on sites of a planar lattice and interact through edges connecting the sites. We only consider the case of a single spin degree of freedom at each site of the lattice. The Yang-Baxter equation for such models takes a particular simple form called the star-triangle relation. Interestigly all known solutions of this relation can be obtained as particular cases of a single "master solution", which is expressed through the elliptic gamma function and have continuous spins taking values of the circle. We show that in the low-temperature (or quasi-classical) limit these lattice models reproduce classical discrete integrable systems on planar graphs previously obtained and classified by Adler, Bobenko and Suris through the consistency-around-a-cube approach. We also discuss inversion relations, the physicical meaning of Baxter's rapidity-independent parameter in the star-triangle relations and the invariance of the action of the classical systems under the star-triangle (or cube-flip) transformation of the lattice, which is a direct consequence of Baxter's Z-invariance in the associated lattice models.
description: Final version
Використання антиплагіатних програм у роботі редакції наукових журналів Харківського національного медичного університету: важливі акценти для авторів
Creators: name: О.С., Шевченко
Publisher: name: Zenodo
Year: 2023
Subjects: академічна доброчесність
плагіат
антиплагіатні програми
academic integrity
plagiarism
anti-plagiarism programs

description: Цитуйте українською у Vancouver style: [Шевченко ОС. Використання антиплагіатних програм у роботі редакції наукових журналів Харківського національного медичного університету: важливі акценти для авторів. Презентація. Вебінар "Антиплагіат-стратегія ХНМУ: поради авторам та експертам" (Україна, Харків, 17 січ 2023). https://doi.org/10.5281/zenodo.7537975]. Презентація на youtube: https://youtu.be/Tj_js6rE-RQ Cite in English in Vancouver style: [Shevchenko AS. The use of anti-plagiarism programs in the editorial work of scientific journals of the Kharkiv National Medical University: important points for authors. Presentation. Webinar "Anti-plagiarism strategy of KhNMU: advice to authors and experts" (Ukraine, Kharkiv, 17 Jan 2023). https://doi.org/10.5281/zenodo.7537975 [in Ukrainian]]. Presentation on youtube: https://youtu.be/Tj_js6rE-RQ [in Ukrainian].
Antecedents of Growth in Network Competition: Quality or Quantity?
Creators: name: McIntyre, David P.
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2007

description: This research examines the impact of two potential antecedents of growth in high-technology, network industries. The first antecedent, installed base, is traditionally framed as a key driver of growth in these settings. The second, product quality, is thought to have only random influences on growth. This work tests the influence of both of these variables on growth in the packaged application software industry, and proposes that their relative influence may be contingent upon the network intensity of a given market or segment. In turn, installed base and timing of product release are proposed to have a significant impact on quality. The sample for this study encompassed five segments of the packaged application software industry from 1986-1998, including word processing, spreadsheets, desktop publishing, CAD, and personal finance. Several results from the empirical analysis offer useful insights into the nature of network industries, and implications for strategic management in these domains. First, installed base size exhibits a negative relationship with growth that becomes more positive as size increases. Second, product quality is positively and significantly associated with installed base growth. Third, the impact of size on growth is shown to vary across industry segments, suggesting that the influence of network effects may not be as homogeneous as extant theory implies. Finally, installed base is associated with higher baseline product quality within periods, consistent with the notion that a large installed base confers learning-based advantages to quality. Together, these findings indicate that competitive dynamics in network industries may be more complex than previously thought. This research extends existing theoretical and empirical work on network effects and positive feedback, and suggests new avenues for effective strategies in emerging high-technology settings.
Predicting clinical concussion measures at baseline and re-test based on academic profile and motivation
Creators: name: Trinidad, Katrina Javier
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2012

description: Purpose: To determine if motivation, unweighted high school grade point average (hsGPA), and Scholastic Assessment Test (SAT) score can predict neurocognitive and postural control performance at baseline and re-test. Participants: 165 incoming student-athletes. Methods: Participants completed a computerized neurocognitive test, a balance test, and a measure of test-taking motivation at baseline and re-test. Statistical Analyses: Twenty-four separate multivariate regression models were used with SAT, hsGPA, and motivation as predictors for baseline and re-test neurocognitive and postural control performance. Results: The model explained a small amount of the variance for the baseline psychomotor speed and complex attention domains and postural control outcomes. Conclusion: Baseline motivation index, SAT and hsGPA do not predict a majority of the clinical concussion measures at baseline and/or re-test but should be considered when assessing the validity of baseline scores.
Quantum Cosmology from Group Field Theory Condensates: a Review
Creators: name: Gielen, Steffen
name: Sindoni, Lorenzo
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: Cosmology and Nongalactic Astrophysics (astro-ph.CO)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences
subject: 83C45, 83C27, 83F05, 81T27

description: We give, in some detail, a critical overview over recent work towards deriving a cosmological phenomenology from the fundamental quantum dynamics of group field theory (GFT), based on the picture of a macroscopic universe as a "condensate" of a large number of quanta of geometry which are given by excitations of the GFT field over a "no-space" vacuum. We emphasise conceptual foundations, relations to other research programmes in GFT and the wider context of loop quantum gravity (LQG), and connections to the quantum physics of real Bose-Einstein condensates. We show how to extract an effective dynamics for GFT condensates from the microscopic GFT physics, and how to compare it with predictions of more conventional quantum cosmology models, in particular loop quantum cosmology (LQC). No detailed familiarity with the GFT formalism is assumed.
SimInf: An R package for Data-driven Stochastic Disease Spread Simulations
Creators: name: Widgren, Stefan
name: Bauer, Pavol
name: Eriksson, Robin
name: Engblom, Stefan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Populations and Evolution (q-bio.PE)
subject: Applications (stat.AP)
subject: Computation (stat.CO)
subject: FOS: Biological sciences
subject: FOS: Computer and information sciences

description: We present the R package SimInf which provides an efficient and very flexible framework to conduct data-driven epidemiological modeling in realistic large scale disease spread simulations. The framework integrates infection dynamics in subpopulations as continuous-time Markov chains using the Gillespie stochastic simulation algorithm and incorporates available data such as births, deaths and movements as scheduled events at predefined time-points. Using C code for the numerical solvers and OpenMP to divide work over multiple processors ensures high performance when simulating a sample outcome. One of our design goal was to make SimInf extendable and enable usage of the numerical solvers from other R extension packages in order to facilitate complex epidemiological research. In this paper, we provide a technical description of the framework and demonstrate its use on some basic examples. We also discuss how to specify and extend the framework with user-defined models.
description: The manual has been updated to the latest version of SimInf (v6.0.0). 41 pages, 16 figures
A refinement of Betti numbers and homology in the presence of a continuous function II (the case of an angle valued map)
Creators: name: Burghelea, Dan
Publisher: name: arXiv
Year: 2016
Subjects: subject: Algebraic Topology (math.AT)
subject: FOS: Mathematics
subject: 55N35, 46M20, 57R19

description: For a continuous angle-valued map defined on a compact ANR, a fixed field and any degree one proposes a refinement of the Novikov-Betti number and of the Novikov homology of the pair consisting of the ANR and the degree one integral cohomology class represented by the map. For each degree the first refinement is a configuration of points with multiplicity located in the punctured complex plane whose total cardinality is the Novikov-Betti number of the pair. The second refinement is a configuration of submodules of the Novikov homology whose direct sum is isomorphic to the Novikov homology and which has the same support as the first configuration. When the field is a the field of complex numbers the second configuration is convertible into a configuration of mutually orthogonal closed Hilbert submodules of the L2-homology of the infinite cyclic cover of the ANR defined by the angle-valued map. One discusses the properties of these configurations namely, robustness with respect to continuous perturbation of the angle-valued map and the Poincaré Duality and one derives some computational applications in topology. The main results parallel the results for the case of real-valued map but with Novikov homology and Novikov-Betti numbers replacing standard homology and standard Betti numbers.
description: 38 pages
Using smog chambers to estimate the toxic effects of reactive atmospheric mixtures
Creators: name: Doyle, Melanie Lynn
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: We live in a dynamic environment with atmospheric pollutants constantly transforming, interacting with one another, and generating secondary pollutants. Many of these secondary pollutants have not been identified and, because they are often more oxygenated, many are more toxic than their parent compounds. Continuous emissions from biogenic and anthropogenic sources into this reactive environment create problematic conditions for evaluating the respiratory toxicity of exposure to individual components of urban atmospheres. While previous investigations have studied individual atmospheric components of air pollution, the evaluation of "one atmosphere" effects has been limited by experimental complexities. In this work, new techniques were developed to create an air-liquid interface exposure system coupled with a controllable atmospheric reactor, or "smog chamber", and these were used to examine various reactive atmospheric mixtures using a laboratory setting that still mimicked the outdoor environment. This smog chamber - in vitro exposure system combines common techniques used in classic toxicology with an outdoor environmental chamber system that was developed to investigate chemical reaction mechanisms. This dissertation is divided into three main parts that demonstrate new methods to study reactive atmospheric pollutants utilizing the smog chamber - in vitro exposure system. In the first part, 1,3-butadiene and isoprene were used to evaluate the differences in respiratory toxicity between unreacted parent pollutants and their complete mixture of products generated during photochemical transformations. The second part applied similar techniques to differentiate the roles that specific photochemical products play in the induction of toxicity mediators; in particular, the role of ozone effects compared to the other known, first generation products. In addition to determining the effects induced by product mixtures generated during photochemical transformations, understanding which products induce the greatest overall effect is particularly helpful when regulating ambient pollutants. In the final part, a preconditioning method was developed to ascertain if repeated ozone exposures modify the respiratory effects induced by subsequent challenges to atmospheric mixtures. Combined, these results characterize and estimate the toxic potential of a realistic, complex, reacting, polluted atmosphere.
Rotating Killing horizons in generic $F(R)$ gravity theories
Creators: name: Bhattacharya, Sourav
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: FOS: Physical sciences

description: We discuss various properties of rotating Killing horizons in generic $F(R)$ theories of gravity in dimension four for spacetimes endowed with two commuting Killing vector fields. Assuming there is no curvature singularity anywhere on or outside the horizon, we construct a suitable $(3+1)$-foliation. We show that similar to Einstein's gravity, we must have $T_{ab}k^ak^b=0$ on the Killing horizon, where $k^a$ is a null geodesic tangent to the horizon. For axisymmetric spacetimes, the effective gravitational coupling $\sim\,F'^{-1}(R)$ should usually depend upon the polar coordinate and hence need not necessarily be a constant on the Killing horizon. We prove that the surface gravity of such a Killing horizon must be a constant, irrespective of whether $F'(R)$ is a constant there or not. We next apply these results to investigate some further basic features. In particular, we show that any hairy solution for the real massive vector field in such theories is clearly ruled out, as long as the potential of the scalar field generated in the corresponding Einstein's frame is a positive definite quantity.
description: v2, 14pp; added references, discussions and clarifications, improved presentation; accepted in GRG
Confidence regions for entries of a large precision matrix
Creators: name: Chang, Jinyuan
name: Qiu, Yumou
name: Yao, Qiwei
name: Zou, Tao
Publisher: name: arXiv
Year: 2016
Subjects: subject: Methodology (stat.ME)
subject: FOS: Computer and information sciences

description: Precision matrices play important roles in many practical applications. Motivated by temporally dependent multivariate data in modern social and scientific studies, we consider the statistical inference of precision matrices for high-dimensional time dependent observations. Specifically, we propose a data-driven procedure to construct a class of simultaneous confidence regions for the precision coefficients within an index set of interest. The confidence regions can be applied to test for specific structures of a precision matrix and to recover its nonzero components. We first construct an estimator of the underlying precision matrix via penalized node-wise regressions, and then develope the Gaussian approximation results on the maximal difference between the estimated and true precision matrices. A computationally feasible parametric bootstrap algorithm is developed to implement the proposed procedure. Theoretical results indicate that the proposed procedure works well without the second order cross-time stationary assumption on the data and sparse structure conditions on the long-run covariance of the estimates. Simulation studies and a real example on S&P 500 stock return data confirm the performance of the proposed approach.
description: The original title of this paper is "On the statistical inference for large precision matrices with dependent data"
Bodies as Stories in Women's Flat Track Roller Derby
Creators: name: Thompson, Elizabeth Ashley
Publisher: name: University of North Carolina at Chapel Hill
Year: 2013

description: As the fastest growing women's sport in the world, roller derby begins with the efforts of groups of everyday women. This paper explores the motivations and experiences of a roller derby league in the Triad region of North Carolina. Borrowing theories from performance studies, gender studies, and folklore and anthropology, this paper considers how participants shape, negotiate, transgress, and play with identity through three central concepts: community, performance, and body. Though roller derby participants come together to take part in a fast-paced, contact team sport, they talk of themselves as a distinct community, meaning their relationships extend beyond shared athletic practice. At the center of the roller derby experience is the way the roller derby community and emergent identities are enacted within and through shared athletic performance. Lastly, this paper considers how participants construct a skater owned-and-operated, women's space in order to critique, explore, and re/imagine the physical body.
Theoretical study of the effective modulus of a composite considering the orientation distribution of the fillers and the weakened interface
Creators: name: Lee, Sangryun
name: Ryu, Seunghwa
Publisher: name: arXiv
Year: 2016
Subjects: subject: Materials Science (cond-mat.mtrl-sci)
subject: FOS: Physical sciences

description: In the manufacturing process of a filler-reinforced composite, the fillers in the matrix are aligned due to the shear flow occurring during the drawing stage, and the interface between the matrix and the fillers form various imperfections that lead to debonding and slip under mechanical loading. Hence, there have been numerous micromechanics studies to predict effective moduli of the composites in the presence of partial alignment of fillers and interface imperfections. In this study, we present an improved theory that overcomes two limitations in the existing micromechanics based approaches. First, we find that the interface damage tensor, which has been developed to model the weakened interface between matrix and fillers, has singularities that cause non-physical predictions (such as infinite or negative effective moduli). We correct the mathematical mistakes to remove singularities and derive analytic expressions of the damage tensor for ellipsoidal inclusions. Second, we reveal that the previous theory on the effective moduli with axisymmetric filler orientation distribution fails because the longitudinal and transverse moduli do not converge in the limit of random orientation distribution. With appropriate corrections, we derive an analytic expression for the orientation average of arbitrary transversely isotropic 4th order tensor under general axisymmetric orientation distribution. We apply the improved method to compute the effective moduli of a representative composite with non-uniform filler orientation and interface damage.
Noether symmetries and duality transformations in cosmology
Creators: name: Paliathanasis, Andronikos
name: Capozziello, Salvatore
Publisher: name: arXiv
Year: 2016
Subjects: subject: General Relativity and Quantum Cosmology (gr-qc)
subject: High Energy Physics - Theory (hep-th)
subject: Mathematical Physics (math-ph)
subject: FOS: Physical sciences

description: We discuss the relation between Noether (point) symmetries and discrete symmetries for a class of minisuperspace cosmological models. We show that when a Noether symmetry exists for the gravitational Lagrangian then there exists a coordinate system in which a reversal symmetry exists. Moreover as far as concerns the scale-factor duality symmetry of the dilaton field, we show that it is related to the existence of a Noether symmetry for the field equations, and the reversal symmetry in the normal coordinates of the symmetry vector becomes scale-factor duality symmetry in the original coordinates. In particular the same point symmetry as also the same reversal symmetry exists for the Brans-Dicke- scalar field with linear potential while now the discrete symmetry in the original coordinates of the system depends on the Brans-Dicke parameter and it is a scale-factor duality when $ω_{BD}=1$. Furthermore, in the context of the O'Hanlon theory for $f\left( R\right) $-gravity, it is possible to show how a duality transformation in the minisuperspace can be used to relate different gravitational models.
description: 12 pages; discussion improved; to appear in MPLA
Nakamaye's theorem on complex manifolds
Creators: name: Tosatti, Valentino
Publisher: name: arXiv
Year: 2016
Subjects: subject: Algebraic Geometry (math.AG)
subject: Complex Variables (math.CV)
subject: FOS: Mathematics
subject: 32J25, 14C20, 32U40, 32U05, 53C55

description: We discuss Nakamaye's Theorem and its recent extension to compact complex manifolds, together with some applications.
description: 26 pages; final version to appear in the Proceedings of the 2015 Summer Institute on Algebraic Geometry
Market Performance in the Food Sector
Creators: name: Farrell, Kenneth R.
name: Farrell, Kenneth R.
Publisher: name: Unknown
Year: 1977
Subjects: subject: Agricultural and Food Policy
subject: Demand and Price Analysis
subject: Industrial Organization
subject: Marketing
subject: FOS: Economics and business

description: Excerpts: Continuing public concern over the performance of the food industry becomes more intense during periods of rapidly rising food prices and/or periods of declining farm prices. Yet either of these situations may be due to economy-wide circumstances beyond the direct control of participants in the food sector. This raises a question of just what market performance is and how one measures and evaluates it. Market performance can be evaluated from many perspectives or points of view. For our purposes, the public interest perspective is more appropriate than that of any particular interest group in the industry or outside it. Market performance means the extent to which the interactions of buyers and sellers in a market—as influenced by market rules and institutions—achieve results that are consistent with the public interest. Thus, analysis of performance should take cognizance of the economic interests of all industry participants—including input suppliers, farmers, cooperatives, processors, distributors, labor organizations, and consumers—and Government rules and regulations.
description: Testimony presented before the California Assembly Special Subcommittee on California's Food and Agricultural Economy, Oct 18, 1976, Sacramento, Calif. Tabular data have been updated to February 1977. Material tor this presentation was provided by Edward Jesse, Commodity Economics Division, ERS, and Dennis Dunham and Charles Handy, National Economics Analysis Division, ERS.
Relative Merits of 3D Visualization for the Detection of Subtle Lung Nodules
Creators: name: Boyce, Sarah J.
Publisher: name: University of North Carolina at Chapel Hill
Year: 2013

description: A new imaging modality called bi-plane correlation imaging (BCI) was examined to determine the merits of using BCI with stereoscopic visualization to detect subtle lung nodules. In the first aim of this project, the optimal geometry for conventional projection imaging applications was assessed using a theoretical model to develop generic results for MTF, NNPS, eDQE. The theoretical model was tested with a clinical system using two magnifications and two anthropomorphic chest phantoms to assess the modalities of single view CXR and stereo/BCI. Results indicated that magnification can potentially improve the signal and noise performance of digital images. Results also demonstrated that a cross over point occurs in the spatial frequency above and below which the effects of magnification differ indicating that there are task dependent tradeoffs associated with magnification. Results indicated that magnification can potentially improve the detection performance primarily due to the air gap which reduced scatter by 30-40%. For both anthropomorphic phantoms, at iso-dose, eDQE(0) for stereo/BCI was ~100 times higher than that for CXR. Magnification at iso-dose improved eDQE(0) by ~10 times for BCI. Increasing the dose did not improve results. The findings indicated that stereo/BCI with magnification may improve detection of subtle lung nodules compared to single view CXR. With quantitative results in place, a pilot clinical trial was constructed. Human subject data was acquired with a BCI acquisition system. Subjects were imaged in the PA position as well as two oblique angles. Realistic simulated lesions were added to a subset of subjects determined to be nodule free. A BCI CAD algorithm was also applied. In randomized readings, radiologists read the cases according to viewing protocol. For the radiologist trainees, the AUC of lesion detection was seen to improve by 2.8% (p < 0.05) for stereoscopic viewing after monoscopic viewing compared to monoscopic viewing only. A 13% decrease in false positives was observed. Stereo/BCI as an adjunct modality was beneficial. However, the full potential of stereo/BCI as a replacement modality for single view chest x-ray may be realized with improved observer training, clinically relevant stereoscopic displays, and more challenging detection tasks.
Esperanza e insatisfacción adolescente en la novela española de finales del siglo veinte: graffiteros, okupas y soñadores
Creators: name: Muñoz-Hermoso, Abel
Publisher: name: The University of North Carolina at Chapel Hill University Libraries
Year: 2006

description: According to literary critic Juan Antonio Masoliver Ródenas, Spanish novels written at the end of the twentieth century reflected Spanish society's dissatisfaction with its government and general pessimism. The purpose of this dissertation is to study five Spanish novels written at that time--Martín Casariego's El chico que imitaba a Roberto Carlos (1996), Lorenzo Silva's Algún día, cuando pueda llevarte a Varsovia (1997), Ray Loriga's Héroes (1993), José Ángel Mañas' Mensaka (1995), and Care Santos' Okupada (1997)--to show that while some authors indeed provided a dark and negative vision of Spanish society, others gave the reader a more optimistic and positive image of the nation and its future. The texts chosen for this study all present the world from the perspective of Spanish adolescents and focus on the many different issues they must confront in an increasingly globalized society. In order to understand the context from which these novels originated, they are analyzed from an urban and cultural perspective. This approach also helps to establish a parallel between a young person’s coming-of-age and the social, political and cultural changes taking place in Spain at the turn the twenty-first century. Given the importance of the development of identity in these texts, the correlation between the Spanish adolescent novel and the tradition of the Bildungsroman is also explored. A key to the process of identity development is the different mechanisms young people rely on to escape (albeit temporarily) from their problems. Some of the alternatives available to adolescents presented in the texts studied here are the use of the imagination, the development of an ecological consciousness, and participation in social youth movements, such as painting graffiti and squatter movements. In the end, the choices made by Casariego, Silva, Loriga, Mañas, and Santos’ protagonists reveal the essential differences among the Spanish novels written in the 1990s. By presenting the reader with an image of youth that is hedonistic and materialistic, Héroes and Mensaka confirm the critics’ assertion that the Spanish novel reflected the nation’s disenchantment and pessimism. However, the level of social engagement that motivates the actions of the protagonists of El chico , Algún día, and Okupada suggests that not all Spanish novelists viewed their nation from the same negative perspective. What is more, the optimistic futures suggested in these three novels positively influence young Spanish readers at a time in their lives when they are developing their own identity as individuals and social beings. By presenting characters that face their problems and explore the various options available to them, these authors indirectly help their adolescent readers who are themselves living similar situations and in the process of becoming adults.
Myosin-X in neuronal development
Creators: name: Raines, Alexander
Publisher: name: University of North Carolina at Chapel Hill
Year: 2012

description: During development, our brains make trillions of connections that enable us to think, feel, and act. Forming these connections requires the precise generation, migration and differentiation of billions of neurons, which extend complex dendritic trees and an axon that can extend nearly a meter. Such complex cellular behaviors are generated by dynamic alterations to the cytoskeleton. Myosin-X (Myo10) is an unconventional myosin known for its functions in filopodia, thin actin-based protrusions thought to act as antennae for cell migration, axon outgrowth, and synapse formation. Myo10 can also directly link actin filaments to integrins and microtubules, interactions that are crucial for many stages in neuronal development. Furthermore, Myo10 can act as a cytoskeletal effector of the phosphoinositide 3-kinase (PI3K) pathway, positioning Myo10 to function downstream of many guidance cues and growth factors. The nervous system expresses a short isoform of Myo10 that lacks a functional motor domain. Termed headless Myo10, this isoform is thought to act as a dominant negative of full-length Myo10, but this hypothesis has not been tested and its function is unknown. Here I show that both full-length and headless Myo10 are expressed in the developing brain in germinal zones where neurons are generated and in neurons as they differentiate. I generated shRNA constructs to selectively knockdown headless and full-length Myo10 in cortical neuron cultures, which reveal opposing roles for Myo10 in axon outgrowth. Co-expression of headless and full-length Myo10 in COS-7 cells demonstrates that headless Myo10 can act as a negative regulator of full-length Myo10. Together, these results suggest that full-length Myo10 promotes axon outgrowth, while headless Myo10 antagonizes full-length Myo10 and limits protrusion. In addition, preliminary experiments and the expression pattern described here indicate that future studies may reveal functions of Myo10 in neurogenesis, neuronal migration and dendritic spine formation.