cometadata/datacite-rtg-text-other-reclassification-records huggingface dataset:
Differential Operator Specializations of Noncommutative Symmetric Functions
Creators: name: Zhao, Wenhua
Publisher: name: arXiv
Year: 2005
Subjects: subject: Combinatorics (math.CO)
subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics
subject: 05E05, 14R10, 16S32 (Primary); 16W20, 16W30 (Secondary)

description: Let $K$ be any unital commutative $\mathbb Q$-algebra and $z=(z_1, ..., z_n)$ commutative or noncommutative free variables. Let $t$ be a formal parameter which commutes with $z$ and elements of $K$. We denote uniformly by $\kzz$ and $\kttzz$ the formal power series algebras of $z$ over $K$ and $K[[t]]$, respectively. For any $α\geq 1$, let $\cDazz$ be the unital algebra generated by the differential operators of $\kzz$ which increase the degree in $z$ by at least $α-1$ and $ \ataz $ the group of automorphisms $F_t(z)=z-H_t(z)$ of $\kttzz$ with $o(H_t(z))\geq α$ and $H_{t=0}(z)=0$. First, for any fixed $α\geq 1$ and $F_t\in \ataz$, we introduce five sequences of differential operators of $\kzz$ and show that their generating functions form a $\mathcal N$CS (noncommutative symmetric) system [Z4] over the differential algebra $\cDazz$. Consequently, by the universal property of the $\mathcal N$CS system formed by the generating functions of certain NCSFs (noncommutative symmetric functions) first introduced in [GKLLRT], we obtain a family of Hopf algebra homomorphisms $\cS_{F_t}: {\mathcal N}Sym \to \cDazz$ $(F_t\in \ataz)$, which are also grading-preserving when $F_t$ satisfies certain conditions. Note that, the homomorphisms $\cS_{F_t}$ above can also be viewed as specializations of NCSFs by the differential operators of $\kzz$. Secondly, we show that, in both commutative and noncommutative cases, this family $\cS_{F_t}$ (with all $n\geq 1$ and $F_t\in \ataz$) of differential operator specializations can distinguish any two different NCSFs. Some connections of the results above with the quasi-symmetric functions ([Ge], [MR], [S]) are also discussed.
description: Latex, 33 pages. Some mistakes and misprints have been corrected
Thermo-mechanical transport in rotor chains
Creators: name: Iacobucci, Alessandra
name: Olla, Stefano
name: Stoltz, Gabriel
Publisher: name: arXiv
Year: 2020
Subjects: subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences
subject: 82-10, 82C05, 82C70

description: We study the macroscopic profiles of temperature and angular momentum in the stationary state of chains of rotors under a thermo-mechanical forcing applied at the boundaries. These profiles are solutions of a system of diffusive partial differential equations with boundary conditions determined by the thermo-mechanical forcing. Instead of expensive Monte Carlo simulations of the underlying microscopic dynamics, we perform extensive numerical computations based on a finite difference method for the system of partial differential equations describing the macroscopic steady state. We first present a formal derivation of these stationary equations based on a linear response argument and local equilibrium assumptions. We then study various properties of the solutions to these equations. This allows to characterize the regime of parameters leading to uphill energy diffusion -- a situation in which the energy flows in the direction of the gradient of temperature -- and to identify regions of parameters corresponding to a negative energy conductivity (i.e. a positive linear response of the energy current to a gradient of temperature). The macroscopic equations we derive are consistent with some previous results obtained by numerical simulation of the microscopic physical system, which confirms their validity.
description: 32 pages, 13 figures
Time-dependent spacetimes in AdS/CFT: Bubble and black hole
Creators: name: Ross, Simon F.
name: Titchener, Georgina
Publisher: name: arXiv
Year: 2004
Subjects: subject: High Energy Physics - Theory (hep-th)
subject: General Relativity and Quantum Cosmology (gr-qc)
subject: FOS: Physical sciences

description: We extend the study of time-dependent backgrounds in the AdS/CFT correspondence by examining the relation between bulk and boundary for the smooth 'bubble of nothing' solution and for the locally AdS black hole which has the same asymptotic geometry. These solutions are asymptotically locally AdS, with a conformal boundary conformal to de Sitter space cross a circle. We study the cosmological horizons and relate their thermodynamics in the bulk and boundary. We consider the alpha-vacuum ambiguity associated with the de Sitter space, and find that only the Euclidean vacuum is well-defined on the black hole solution. We argue that this selects the Euclidean vacuum as the preferred state in the dual strongly coupled CFT.
description: 25 pages, 3 figures; reference added
Pentachaetus Kim & Boxshall 2020, gen. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Cyclopoida
Notodelphyidae
Pentachaetus

description: Pentachaetus gen. nov.
Diagnosis. Body form as in Doroixys. Dorsal cephalic shield bearing paired horn-like processes posterolaterally. Fifth pedigerous somite fused with fourth. Free urosome 5-segmented. Caudal ramus bearing 5 well-developed setae (2 proximal and 3 distal). Rostrum well-developed. Antennule 6-segmented; first segment armed with 2 setae. Antenna 3-segmented, comprising coxa, basis, and unsegmented endopod; terminal claw small. Labrum weak, flexible. Mandible similar to that of Doroixys; exopod armed with 5 setae; endopod 2-segmented with 1 seta on first segment and 4 setae on second. Maxillule as in Doroixys, lacking coxal endite. Maxilla 4-segmented, bearing 4 setae on first endite of syncoxa, claw plus 2 setaeon basis, and 2-segmented endopodarmedwith 1 and 3 setae on first and second segments, respectively. Maxilliped unsegmented with 6 setae. Leg 1 with 2- or 3-segmented exopod and 3-segmented endopod; second exopodal segment (or original second exopodal segment) lacking outer element. Leg 2 with 3-segmented rami. Legs 3 and 4 with 3-segmented exopods and 2-segmented endopods. Inner coxal seta absent in legs 1–4. First and second exopodal segments of legs 2–4 lacking inner seta. Legs 2–4 with setal armature only on terminal endopodal segments. Leg 5 represented by 2 processes and 2 setae.
Etymology. The generic name is derived from the Greek penta (=five) and chaet (=a bristle) and refers to the presence of five setae on the caudal ramus. Gender masculine.
Typespecies. Pentachaetusspinatus gen. etsp. nov. by original designation.
Other included species. Pentachaetus palauensis gen. etsp. nov. and P. longisetatus gen. etsp. nov.
Remarks. The three species placed in this new genus constituteahomogeneousgroup andcanbe separatedfrom the closely related genus, Doroixys, by two prominent features: firstly, the caudal ramus is armedwith 5 (not 6) well-developed setae, and secondly, the second exopodal segment (or original second exopodal segment) of leg 1 lacks an outer setal element.
description: Published as part of Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), pp. 1-6 in Megataxa 4 (1) on page 494, DOI: 10.11646/megataxa.4.1.1, http://zenodo.org/record/4591138
Are Lower Income Households Willing and Able To Budget for Fruits and Vegetables?
Creators: name: Stewart, Hayden
name: Blisard, Noel
name: Stewart, Hayden
name: Blisard, Noel
Publisher: name: Unknown
Year: 2008
Subjects: subject: Agricultural and Food Policy
subject: Consumer/Household Economics
subject: Financial Economics
subject: Food Consumption/Nutrition/Food Safety
subject: food expenditures
subject: fruits
subject: vegetables
subject: hierarchical demand
subject: low-income households
subject: food spending

description: Households have a number of needs and wants that all compete for scarce resources. Given this situation, are low-income households, in particular, generally willing and able to budget for healthful foods like fruits and vegetables, or are other goods and services, including other foods, more of a priority? For six out of seven selected types of food, we find that households with an income below 130 percent of the poverty line spend less money than higher income households. However, we also find that these households, when given a small increase in income, will allocate more money to only two out of the seven products, beef and frozen prepared foods. These foods may be priorities for reasons of taste and convenience. For additional money to be allocated to fruits and vegetables, a household’s income needs to be slightly greater than 130 percent of the poverty line.
Radio Afterglows of Gamma-Ray Bursts and Hypernovae at High Redshift, and their Potential for 21-cm Absorption Studies
Creators: name: Ioka, Kunihito
name: Meszaros, Peter
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We investigate the radio afterglows of gamma-ray bursts (GRBs) and hypernovae (HNe) at high redshifts and quantify their detectability, as well as their potential usefulness for 21 cm absorption line studies of the intergalactic medium (IGM) and intervening structures. We examine several sets of source and environment model parameters that are physically plausible at high redshifts. The radio afterglows of GRBs would be detectable out to z ~ 30, while the energetic HNe could be detectable out to z ~ 20 even by the current Very Large Array (VLA). We find that the 21 cm absorption line due to the diffuse neutral IGM is difficult to detect even by the proposed Square Kilometer Array (SKA), except for highly energetic sources. We also find that the 21 cm line due to collapsed gas clouds with high optical depth may be detected on rare occasions.
description: 36 pages, 12 figures, 1 table, accepted for publication in ApJ
Diceratus Kim & Boxshall 2020, gen. nov.
Creators: name: Kim, Il-Hoi
name: Boxshall, Geoff A.
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Copepoda
Cyclopoida
Notodelphyidae
Diceratus

description: Diceratus gen. nov.
Diagnosis. Body form as in Doroixys. Dorsal cephalic shield bearing 2 pairs of horn-like processes posterolaterally. Freeurosome 5-segmented. Rostrum well-developed. Antennule 7- or 8-segmented. Antenna 3-segmented, consistingof coxa, basis, and unsegmented endopod bearing terminal claw. Mandible with enlarged distaltoothand 1 or 2 subsidiaryteethoncoxal gnathobase; basiswith 1 setaonmedial margin; exopodwith 5 setae; endopod with 1 and 7 setaeon first and second segments, respectively. Maxillulewith 5 or 6 setaeon arthrite, 1 on epipodite, 2 on basis, 4 onexopodand 3 on endopod; coxal endite absent. Maxilla 4-segmented, armedwith 3, 2, and 2 setae on first to third syncoxal endites, respectively, strong claw plus 2 setae on basis, and with1 and 3 setae on first and second endopodal segments, respectively. Maxilliped unsegmented with 2 setae. Legs 1–4 biramous. Inner coxal seta absent in legs 1–4. Leg 1 with inner distal setaon basis; endopod 2- or 3-segmented; exopodwith 2, 2, and 7 armature elements on first to third segments, respectively. Legs 2–4 with 3-segmented rami; first and second segments of exopods and endopods lacking inner setae. Leg 5 consisting of digitiform outer protopodal process tipped with 1 seta, and claw-like inner exopodal process bearing 1 setaon outer margin.
Etymology. The generic name is derived from the Greek di (=double) and cerat (=horn), referring to the presence of the double posterolateral processes on the dorsalcephalic shield.
Type species. Diceratus unidentatus gen. et sp. nov. by original designation.
Other included species. Diceratus bispinosus (Ooishi, 1998) comb. nov. (originally described as Doroixys bispinosa Ooishi, 1998)
Remarks. Ooishi (1998) originally placed Diceratus bispinosa (Ooishi, 1998) comb. nov. in the genus Doroixys. Detailed comparison of this species with the newly discovered Diceratus unidentatus gen. et sp. nov. revealsthatthey sharenumerousdistinctivefeatureswhich justify their placement in an independent new genus. The shared features of these two species include the presence of twopairs of cephalic processes, the enlargeddistal tooth on the coxal gnathobase of the mandible, the presence of 2 setae on the basis of the maxillule, and the presence of only 2 setae on the maxilliped.
description: Published as part of Kim, Il-Hoi & Boxshall, Geoff A., 2020, Untold diversity: the astonishing species richness of the Notodelphyidae (Copepoda: Cyclopoida), a family of symbiotic copepods associated with ascidians (Tunicata), pp. 1-6 in Megataxa 4 (1) on page 503, DOI: 10.11646/megataxa.4.1.1, http://zenodo.org/record/4591138
Price Trends Are Similar for Fruits, Vegetables, and Snack Foods
Creators: name: Kuchler, Fred
name: Stewart, Hayden
name: Kuchler, Fred
name: Stewart, Hayden
Publisher: name: Unknown
Year: 2008
Subjects: subject: Agricultural and Food Policy
subject: Consumer/Household Economics
subject: Demand and Price Analysis
subject: Financial Economics
subject: Food Consumption/Nutrition/Food Safety
subject: Health Economics and Policy
subject: fresh fruit and vegetable prices
subject: price trends
subject: quality change

description: An increase in the price of fruits and vegetables relative to less healthy foods could reduce consumers’ incentives to purchase fruits and vegetables and result in less healthy diets. Whether such a change in relative prices and incentives has occurred in the United States is difficult to prove because of substantial quality improvements in many fresh fruits and vegetables. For commonly consumed fresh fruits and vegetables for which quality has remained fairly constant, analysis of price trends reveals a price decline similar to that of dessert and snack foods. This price trend evidence suggests that the price of a healthy diet has not changed relative to an unhealthy one, although a healthy diet might not include every fresh fruit or vegetable currently available.
$\mathcal{PT}$ symmetry of a square-wave modulated two-level system
Creators: name: Duan, Liwei
name: Wang, Yan-Zhi
name: Chen, Qing-Hu
Publisher: name: arXiv
Year: 2020
Subjects: subject: Quantum Physics (quant-ph)
subject: Atomic Physics (physics.atom-ph)
subject: FOS: Physical sciences

description: We study a non-Hermitian two-level system with square-wave modulated dissipation and coupling. Based on the Floquet theory, we achieve an effective Hamiltonian from which the boundaries of the $\mathcal{PT}$ phase diagram are captured exactly. Two kinds of $\mathcal{PT}$ symmetry broken phases are found whose effective Hamiltonians differ by a constant $ω/ 2$. For the time-periodic dissipation, a vanishingly small dissipation strength can lead to the $\mathcal{PT}$ symmetry breaking in the $(2k-1)$-photon resonance ($Δ= (2k-1) ω$), with $k=1,2,3\dots$ It is worth noting that such a phenomenon can also happen in $2k$-photon resonance ($Δ= 2k ω$), as long as the dissipation strengths or the driving times are imbalanced, namely $γ_0 \ne - γ_1$ or $T_0 \ne T_1$. For the time-periodic coupling, the weak dissipation induced $\mathcal{PT}$ symmetry breaking occurs at $Δ_{\mathrm{eff}}=kω$, where $Δ_{\mathrm{eff}}=\left(Δ_0 T_0 + Δ_1 T_1\right)/T$. In the high frequency limit, the phase boundary is given by a simple relation $γ_{\mathrm{eff}}=\pmΔ_{\mathrm{eff}}$.
description: 9 pages, 5 figures
Predictions of microstructure and stress in planar extensional flows of a dense viscous suspension
Creators: name: Jenkins, James T.
name: Seto, Ryohei
name: La Ragione, Luigi
Publisher: name: arXiv
Year: 2020
Subjects: subject: Fluid Dynamics (physics.flu-dyn)
subject: Soft Condensed Matter (cond-mat.soft)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: We consider extensional flows of a dense layer of spheres in a viscous fluid and employ force and torque balances to determine the trajectory of particle pairs that contribute to the stress. In doing this, we use Stokesian dynamics simulations to guide the choice of the near-contacting pairs that follow such a trajectory. We specify the boundary conditions on the representative trajectory, and determine the distribution of particles along it and how the stress depends on the microstructure and strain rate. We test the resulting predictions using the numerical simulations. Also, we show that the relation between the tensors of stress and strain rate involves the second and fourth moments of the particle distribution function.
description: 21 pages, 6 figures
What Does the “Family Smoking Prevention and Tobacco Control Act” Mean to Tobacco Growers?
Creators: name: Tiller, Kelly
name: Starnes, Jane H.
name: Feleke, Shiferaw T.
name: Tiller, Kelly
name: Starnes, Jane H.
name: Feleke, Shiferaw T.
Publisher: name: Unknown
Year: 2010
Subjects: subject: Agricultural and Food Policy
subject: Crop Production/Industries
subject: Demand and Price Analysis
subject: Farm Management
subject: Policy
subject: Tobacco
subject: Family Smoking Prevention and Tobacco Control Act

description: The “Family Smoking Prevention and Tobacco Control Act” was signed into law on June 22, 2009. The bill grants the Federal Food and Drug Administration (FDA) an authority to regulate the manufacturing and marketing of tobacco products. Tobacco leaf is not subject to the regulation. As a result, it is not apparent what it does mean to tobacco growers. However, since the demand for tobacco is in large part determined by the demand for cigarettes, a change in demand for cigarettes due to the FDA regulation can affect the demand for tobacco. This paper explores the economic welfare consequences of the bill to tobacco growers.
Banach Space Representer Theorems for Neural Networks and Ridge Splines
Creators: name: Parhi, Rahul
name: Nowak, Robert D.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Machine Learning (stat.ML)
subject: Machine Learning (cs.LG)
subject: FOS: Computer and information sciences

description: We develop a variational framework to understand the properties of the functions learned by neural networks fit to data. We propose and study a family of continuous-domain linear inverse problems with total variation-like regularization in the Radon domain subject to data fitting constraints. We derive a representer theorem showing that finite-width, single-hidden layer neural networks are solutions to these inverse problems. We draw on many techniques from variational spline theory and so we propose the notion of polynomial ridge splines, which correspond to single-hidden layer neural networks with truncated power functions as the activation function. The representer theorem is reminiscent of the classical reproducing kernel Hilbert space representer theorem, but we show that the neural network problem is posed over a non-Hilbertian Banach space. While the learning problems are posed in the continuous-domain, similar to kernel methods, the problems can be recast as finite-dimensional neural network training problems. These neural network training problems have regularizers which are related to the well-known weight decay and path-norm regularizers. Thus, our result gives insight into functional characteristics of trained neural networks and also into the design neural network regularizers. We also show that these regularizers promote neural network solutions with desirable generalization properties.
description: update to published version
Convergence in Global Food Demand and Delivery
Creators: name: Regmi, Anita
name: Takeshima, Hiroyuki
name: Unnevehr, Laurian J.
name: Regmi, Anita
name: Takeshima, Hiroyuki
name: Unnevehr, Laurian J.
Publisher: name: Unknown
Year: 2008
Subjects: subject: Agricultural and Food Policy
subject: Consumer/Household Economics
subject: Financial Economics
subject: Food Consumption/Nutrition/Food Safety
subject: International Relations/Trade
subject: food expenditure
subject: food delivery
subject: food demand convergence
subject: retail food sales
subject: foodservice sales
subject: food label claims
subject: supermarket sales
subject: fast-food sales
subject: global food market.

description: Using food expenditures and food sales data over 1990-2004, this report examines whether food consumption and delivery trends are converging across 47 high- and middle-income countries. Middle-income countries, such as China and Mexico, appear to be following trends in high-income countries, measured across several dimensions of food system growth and change. Convergence is apparent in most important food expenditure categories and in indicators of food system modernization such as supermarket and fast-food sales.
Noncommutative Symmetric Functions and the Inversion Problem
Creators: name: Zhao, Wenhua
Publisher: name: arXiv
Year: 2005
Subjects: subject: Complex Variables (math.CV)
subject: Combinatorics (math.CO)
subject: FOS: Mathematics
subject: 05E05, 14R10, 14C15

description: Let $K$ be any unital commutative $\bQ$-algebra and $z=(z_1, z_2, ..., z_n)$ commutative or noncommutative variables. Let $t$ be a formal central parameter and $\kttzz$ the formal power series algebra of $z$ over $K[[t]]$. In \cite{GTS-II}, for each automorphism $F_t(z)=z-H_t(z)$ of $\kttzz$ with $H_{t=0}(z)=0$ and $o(H(z))\geq 1$, a \cNcs (noncommutative symmetric) system (\cite{GTS-I}) $\Oft$ has been constructed. Consequently, we get a Hopf algebra homomorphism $\cSft: \cNsf \to \cDzz$ from the Hopf algebra $\cNsf$ (\cite{G-T}) of NCSF's (noncommutative symmetric functions). In this paper, we first give a list for the identities between any two sequences of differential operators in the \cNcs system $\Oft$ by using some identities of NCSF's derived in \cite{G-T} and the homomorphism $\cSft$. Secondly, we apply these identities to derive some formulas in terms of differential operator in the system $\Oft$ for the Taylor series expansions of $u(F_t)$ and $u(F_t^{-1})$ $(u(z)\in \kttzz)$; the D-Log and the formal flow of $F_t$ and inversion formulas for the inverse map of $F_t$. Finally, we discuss a connection of the well-known Jacobian conjecture with NCSF's.
description: Latex, 33 pages. Some misprints have been corrected
Phase transitions in the pseudogap Anderson and Kondo models: Critical dimensions, renormalization group, and local-moment criticality
Creators: name: Fritz, Lars
name: Vojta, Matthias
Publisher: name: arXiv
Year: 2004
Subjects: subject: Strongly Correlated Electrons (cond-mat.str-el)
subject: Statistical Mechanics (cond-mat.stat-mech)
subject: FOS: Physical sciences

description: The pseudogap Kondo problem, describing quantum impurities coupled to fermionic quasiparticles with a pseudogap density of states, rho(omega) ~ |omega|^r, shows a rich zero-temperature phase diagram, with different screened and free moment phases and associated transitions. We analyze both the particle-hole symmetric and asymmetric cases using renormalization group techniques. In the vicinity of r=0, which plays the role of a lower-critical dimension, an expansion in the Kondo coupling is appropriate. In contrast, r=1 is the upper-critical dimension in the absence of particle-hole symmetry, and here insight can be gained using an expansion in the hybridization strength of the Anderson model. As a by-product, we show that the particle-hole symmetric strong-coupling fixed point for r<1 is described by a resonant level model, and corresponds to an intermediate-coupling fixed point in the renormalization group language. Interestingly, the value r=1/2 plays the role of a second lower-critical dimension in the particle-hole symmetric case, and there we can make progress by a novel expansion performed around a resonant level model. The different expansions allow a complete description of all critical fixed points of the models and can be used to compute a variety of properties near criticality, describing universal local-moment fluctuations at these impurity quantum phase transitions.
description: 26 pages, 14 figs; (v2) final version as published
Eligibility to participate in the Olympics : ways to improve how disputes are resolved at games time
Creators: name: Hopewell, Nicholas James
Publisher: name: University of British Columbia
Year: 2009

description: Eligibility disputes at the Olympic Games are ultimately resolved by the Ad Hoc Division ("AHD") of the Court of Arbitration for Sport. This paper critically examines the AHD both from within and without. The first part of this thesis describes eligibility disputes at Games time, and how they are resolved. The paper begins with a brief look at the history of athlete participation in the Olympic Games. It then deals with the concept of eligibility, and sets out the rules which govern same for the Olympics. These rules are set by a number of separate but related entities, namely the International Olympic Committee, the International Federations, the National Olympic Committees, and, finally, the World Anti-Doping Agency. The roles of each of these bodies are examined in order to provide the context in which disputes are resolved. This paper then surveys the parameters in which the AHD operates which have been set over the years by domestic courts with an Anglo-American tradition. The performance of the AHD is then critically examined with a view to making recommendations for its improvement. The second part of this thesis surveys the ways eligibility disputes are resolved in the major north American professional sports leagues and the NCAA, with a view to suggesting improvements in the AHD process. This thesis concludes by offering recommendations to the AHD process in two areas: operational and structural. Several operational improvements are suggested, the main ones of which are that all parties affected by a dispute be offered an opportunity to participate in before the AHD, and parties be given the opportunity to appoint the Panel. The structural change suggested is that athletes be given formal input into the administration of the Games, with the Athletes' Commission being the obvious body which could form the basis for a bargaining unit. It is suggested that questions surrounding the legitimacy of AHD will remain while ever athletes have no formal say in its composition or operation.
The status of household food security targets in South Africa
Creators: name: Jacobs, Peter T.
name: Jacobs, Peter T.
Publisher: name: Unknown
Year: 2009
Subjects: subject: Consumer/Household Economics
subject: food security
subject: dietary energy cost
subject: household expenditure
subject: methodology
subject: South Africa

description: This article investigates the conceptual and methodological challenges to develop a set of baseline indicators for South African food security targets. A food security target is a well-defined and measurable goal to reduce the numbers of people who lack enough food of the right quality to live healthy lives. To derive baseline indicators for household food security, the following question is asked: what is the average cost of a nutritionally adequate food basket per person? The cost of recommended nutrient intake is based on estimates of dietary energy costs. Reported food expenditure for each household based on 2005/2006 Income and Expenditure Survey data gets compared to two dietary energy cost baskets. The food expenditure shares of the poorest households vary between 38% and 71% according to different surveys. At food expenditure levels reported in the IES, one in five households meet their average dietary energy cost. Deep levels of food insecurity exist in rural areas with 85% of rural households unable to afford even the ‘below average dietary energy costs’. Food security policy based on refined baseline indicators can better target food insecure households. Another policy benefit is that robust indicators help to develop effective monitoring capabilities.
Cospectrality preserving graph modifications and eigenvector properties via walk equivalence of vertices
Creators: name: Morfonios, Christian V.
name: Pyzh, Maxim
name: Röntgen, Malte
name: Schmelcher, Peter
Publisher: name: arXiv
Year: 2020
Subjects: subject: Combinatorics (math.CO)
subject: Quantum Physics (quant-ph)
subject: FOS: Mathematics
subject: FOS: Physical sciences
subject: 05C50, 15A18, 05C22, 81R40, 81V55

description: Originating from spectral graph theory, cospectrality is a powerful generalization of exchange symmetry and can be applied to all real-valued symmetric matrices. Two vertices of an undirected graph with real edge weights are cospectral iff the underlying weighted adjacency matrix $M$ fulfills $[M^k]_{u,u} = [M^k]_{v,v}$ for all non-negative integer $k$, and as a result any eigenvector $ϕ$ of $M$ has (or, in the presence of degeneracies, can be chosen to have) definite parity on $u$ and $v$. We here show that the powers of a matrix with cospectral vertices induce further local relations on its eigenvectors, and also can be used to design cospectrality preserving modifications. To this end, we introduce the concept of \emph{walk equivalence} of cospectral vertices with respect to \emph{walk multiplets} which are special vertex subsets of a graph. Walk multiplets allow for systematic and flexible modifications of a graph with a given cospectral pair while preserving this cospectrality. The set of modifications includes the addition and removal of both vertices and edges, such that the underlying topology of the graph can be altered. In particular, we prove that any new vertex connected to a walk multiplet by suitable connection weights becomes a so-called unrestricted substitution point (USP), meaning that any arbitrary graph may be connected to it without breaking cospectrality. Also, suitable interconnections between walk multiplets within a graph are shown to preserve the associated cospectrality. Importantly, we demonstrate that the walk equivalence of cospectral vertices $u,v$ imposes a local structure on every eigenvector $ϕ$ obeying $ϕ_{u} = \pm ϕ_{v} \ne 0$ (in the case of degeneracies, a specific choice of the eigenvector basis is needed). Our work paves the way for flexibly exploiting hidden structural symmetries in the design of generic complex network-like systems.
Should subsistence agriculture be supported as a strategy to address rural food insecurity?
Creators: name: Aliber, Michael
name: Hart, Tim G.B.
name: Aliber, Michael
name: Hart, Tim G.B.
Publisher: name: Unknown
Year: 2009
Subjects: subject: Consumer/Household Economics
subject: subsistence production
subject: Labour Force Survey
subject: traditional crops
subject: local agricultural practices

description: At first glance South Africa’s black farming sector appears to contribute rather minimally to overall agricultural output in South Africa. However, despite the complexity involved in this sector and the often marginal conditions in which agriculture is practised it appears to be important to a large number of black households. Furthermore, the significance they attach to subsistence agriculture as means of supplementing household food supplies seems to heavily outweigh other reasons for engaging in agriculture. Some South African researchers have indicated the contribution subsistence production makes to household food security, despite the prevalent complexities and the low input nature of this production. Statistics South Africa’s Labour Force Survey data from 2001 to 2007 and a case study of subsistence farming in Limpopo Province are used to support the argument that, despite the complexity of this sector, the more than 4 million subsistence farmers, need and merit greater support. Such support should be based on the local context, build on and, where appropriate, improve existing local practices, while addressing various existing threats to this type of production. Recommendations are made as to what policy makers need to consider when considering how best to support subsistence production.
A Noncommutative Symmetric System over the Grossman-Larson Hopf Algebra of Labeled Rooted Trees
Creators: name: Zhao, Wenhua
Publisher: name: arXiv
Year: 2005
Subjects: subject: Combinatorics (math.CO)
subject: Quantum Algebra (math.QA)
subject: FOS: Mathematics
subject: 05E05, 16W30 (Primary); 06A07, 06A11 (Secondary)

description: In this paper, we construct explicitly a noncommutative symmetric (${\mathcal N}$CS) system over the Grossman-Larson Hopf algebra of labeled rooted trees. By the universal property of the ${\mathcal N}$CS system formed by the generating functions of certain noncommutative symmetric functions, we obtain a specialization of noncommutative symmetric functions by labeled rooted trees. Taking the graded duals, we also get a graded Hopf algebra homomorphism from the Connes-Kreimer Hopf algebra of labeled rooted forests to the Hopf algebra of quasi-symmetric functions. A connection of the coefficients of the third generating function of the constructed ${\mathcal N}$CS system with the order polynomials of rooted trees is also given and proved.
description: Latex, 30 pages. Following the referees' suggestions, several places have been improved. In particular, some diagrams of rooted trees have been added. To appear in J. Alg. Comb
Galaxy classification: deep learning on the OTELO and COSMOS databases
Creators: name: de Diego, José A.
name: Nadolny, Jakub
name: Bongiovanni, Ángel
name: Cepa, Jordi
name: Pović, Mirjana
name: García, Ana María Pérez
name: Torres, Carmen P. Padilla
name: Lara-López, Maritza A.
name: Cerviño, Miguel
name: Martínez, Ricardo Pérez
name: Alfaro, Emilio J.
name: Castañeda, Héctor O.
name: Fernández-Lorenzo, Miriam
name: Gallego, Jesús
name: González, J. Jesús
name: González-Serrano, J. Ignacio
name: Pintos-Castro, Irene
name: Sánchez-Portal, Miguel
name: Cedrés, Bernab?
name: González-Otero, Mauro
name: Jones, D. Heath
name: Bland-Hawthorn, Joss
Publisher: name: arXiv
Year: 2020
Subjects: subject: Astrophysics of Galaxies (astro-ph.GA)
subject: FOS: Physical sciences

description: Context. The accurate classification of hundreds of thousands of galaxies observed in modern deep surveys is imperative if we want to understand the universe and its evolution. Aims. Here, we report the use of machine learning techniques to classify early- and late-type galaxies in the OTELO and COSMOS databases using optical and infrared photometry and available shape parameters: either the Sersic index or the concentration index. Methods. We used three classification methods for the OTELO database: 1) u-r color separation , 2) linear discriminant analysis using u-r and a shape parameter classification, and 3) a deep neural network using the r magnitude, several colors, and a shape parameter. We analyzed the performance of each method by sample bootstrapping and tested the performance of our neural network architecture using COSMOS data. Results. The accuracy achieved by the deep neural network is greater than that of the other classification methods, and it can also operate with missing data. Our neural network architecture is able to classify both OTELO and COSMOS datasets regardless of small differences in the photometric bands used in each catalog. Conclusions. In this study we show that the use of deep neural networks is a robust method to mine the cataloged data
description: 20 pages, 10 tables, 14 figures, Astronomy and Astrophysics (in press)
Two blocks connected by a string with variable tension: A dynamic case
Creators: name: Suárez, H. J. Herrera
name: Higuera, M. Machado -
name: Muñoz, J. H.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Physics Education (physics.ed-ph)
subject: FOS: Physical sciences

description: In this paper, the dynamic case of a system made up of two blocks connected by a string over a smooth pulley is revisited. One mass lies on a horizontal surface without friction, and the other mass has a vertical displacement. The motion equation is obtained and its solution is determined using the Mathematica package. Also, an experimental montage for this system is made and experimental data for the vertical position $y$ in function of the time $t$ are obtained using a Data Acquisition System and the Tracker video analysis. The relation $y$ vs $t$ can be represented by a polynomial of degree six. An average relative error of 3.61 (10.14) % is obtained between the theoretical results acquired with Mathematica and the data taken from the Tracker (Data Acquisition System).
description: 8 pages, 10 figures
The contribution of subsistence farming to food security in South Africa
Creators: name: Baiphethi, Mompati N.
name: Jacobs, Peter T.
name: Baiphethi, Mompati N.
name: Jacobs, Peter T.
Publisher: name: Unknown
Year: 2009
Subjects: subject: Consumer/Household Economics
subject: subsistence farming
subject: livelihoods
subject: agro-food markets
subject: farm inputs
subject: food security

description: Poor households access their food from the market, subsistence production and transfers from public programmes or other households. In the past rural households produced most of their own food, but recent studies have shown an increase in dependence on market purchases by both urban and rural households, in some cases reaching 90% of the food supplies. Food expenditures can account for as much as 60–80% of total household income for low-income households in some parts of sub-Saharan Africa. Subsistence/smallholder agriculture can play an important role in reducing the vulnerability of rural and urban food-insecure households, improving livelihoods, and helping to mitigate high food price inflation. There is a need to significantly increase the productivity of subsistence/smallholder agriculture and ensure long-term food security. This can be achieved by encouraging farmers to pursue sustainable intensification of production through the use of improved inputs. This will require a dramatic increase in the use of fertiliser, organic inputs and conservation investments, combined with the development of well-functioning input and output markets to help farmers acquire and use improved inputs, market their (surplus) output and reduce transaction costs and risks. Increased productivity will reduce pressure on marginal lands, as the intensification of cultivated land will reduce pressure to crop fragile marginal lands. There is a need to determine methods of identifying cost-effective ways to improve access to inputs by, among other things, improving delivery, and assisting farmers to earn cash to purchase inputs and invest in infrastructure, thereby improving food security.
PPFP Choices Kenya and Indonesia Postabortion Care Interview 2
Creators: name: Charurat, Elaine
name: Olapeju, Bolanle
name: Kennedy, Sara
name: Breithaupt, Lindsay
name: Christofield, Megan
name: Schuster, Anne
Publisher: name: figshare
Year: 2020
Subjects: subject: Health Care
subject: 111707 Family Care
subject: FOS: Health sciences

description: This is the English version of the 6-month postabortion care interview tool (Interview PAC 2) for Jhpiego's Post Pregnancy Family Planning Choices (PPFP Choices) operations research study in Kenya and Indonesia. Included are the English, Bahasa, Kiswahili and Kimeru versions of the Interview.
Supersonic Motions of Galaxies in Clusters
Creators: name: Faltenbacher, Andreas
name: Kravtsov, Andrey V.
name: Nagai, Daisuke
name: Gottloeber, Stefan
Publisher: name: arXiv
Year: 2004
Subjects: subject: Astrophysics (astro-ph)
subject: FOS: Physical sciences

description: We study motions of galaxies in galaxy clusters formed in the concordance LCDM cosmology. We use high-resolution cosmological simulations that follow dynamics of dark matter and gas and include various physical processes critical for galaxy formation: gas cooling, heating and star formation. Analysing motions of galaxies and the properties of intracluster gas in the sample of eight simulated clusters at z=0, we study velocity dispersion profiles of the dark matter, gas, and galaxies. We measure the mean velocity of galaxy motions and gas sound speed as a function of radius and calculate the average Mach number of galaxy motions. The simulations show that galaxies, on average, move supersonically with the average Mach number of ~1.4, approximately independent of the cluster-centric radius. The supersonic motions of galaxies may potentially provide an important source of heating for the intracluster gas by driving weak shocks and via dynamical friction, although these heating processes appear to be inefficient in our simulations. We also find that galaxies move faster than the dark matter particles in clusters. The magnitude of the velocity bias, b_v~1.1, is, however, smaller than the bias estimated for subhalos in dissipationless simulations. Interestingly, we find velocity bias in the tangential component of the velocity dispersion, but not in the radial component. Finally, we find significant random bulk motions of gas. The typical gas velocities are of order ~20-30% of the gas sound speed. These random motions provide about 10% of the total pressure support in our simulated clusters. The non-thermal pressure support, if neglected, will bias measurements of the total mass in the hydrostatic analyses of the X-ray cluster observations.
description: accepted for publication in MNRAS, 11 pages, 6 figures, added explanation of the measured average Mach number and discussion of the velocity bias
pinta: The uGMRT Data Processing Pipeline for the Indian Pulsar Timing Array
Creators: name: Susobhanan, Abhimanyu
name: Maan, Yogesh
name: Joshi, Bhal Chandra
name: Prabu, T.
name: Desai, Shantanu
name: Nobleson, K.
name: Susarla, Sai Chaitanya
name: Girgaonkar, Raghav
name: Dey, Lankeswar
name: Batra, Neelam Dhanda
name: Gupta, Yashwant
name: Gopakumar, A.
name: Bagchi, Manjari
name: Basu, Avishek
name: Bethapudi, Suryarao
name: Choudhary, Arpita
name: De, Kishalay
name: Krishnakumar, M. A.
name: Manoharan, P. K.
name: Naidu, Arun Kumar
name: Pathak, Dhruv
name: Singha, Jaikhomba
name: Surnis, Mayuresh P.
Publisher: name: arXiv
Year: 2020
Subjects: subject: Instrumentation and Methods for Astrophysics (astro-ph.IM)
subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences

description: We introduce pinta, a pipeline for reducing the upgraded Giant Metre-wave Radio Telescope (uGMRT) raw pulsar timing data, developed for the Indian Pulsar Timing Array experiment. We provide a detailed description of the workflow and usage of pinta, as well as its computational performance and RFI mitigation characteristics. We also discuss a novel and independent determination of the relative time offsets between the different back-end modes of uGMRT and the interpretation of the uGMRT observation frequency settings, and their agreement with results obtained from engineering tests. Further, we demonstrate the capability of pinta to generate data products which can produce high-precision TOAs using PSR J1909-3744 as an example. These results are crucial for performing precision pulsar timing with the uGMRT.
Boosting smallholder production for food security: some approaches and evidence from studies in sub-Saharan Africa
Creators: name: Matshe, Innocent
name: Matshe, Innocent
Publisher: name: Unknown
Year: 2009
Subjects: subject: Consumer/Household Economics
subject: food security
subject: livelihoods
subject: smallholder agriculture
subject: sub-Saharan Africa

description: This paper uses the sustainable livelihoods framework to explore the contribution of smallholder production to food security in some sub-Saharan African countries and relates it to the South African case. Noting that many of the world’s hungry are smallholder farmers, it is clear that food insecurity is closely linked to the livelihood strategies of these farm households. As previous studies have shown, food insecurity is linked to livelihood assets, strong institutional support and a favourable external environment. In particular, the paper finds that food security depends on cereal output, budgetary support to agriculture, agricultural value added and poverty – all variables strongly linked to the sustainable livelihoods framework. Since most poor rural households rely on agricultural production for a significant share of their household income, increasing agricultural productivity is critical to increase food security and reduce rural poverty.
PPFP Choices Kenya and Indonesia Postabortion Care Interview 1
Creators: name: Charurat, Elaine
name: Olapeju, Bolanle
name: Kennedy, Sara
name: Breithaupt, Lindsay
name: Christofield, Megan
name: Schuster, Anne
Publisher: name: figshare
Year: 2020
Subjects: subject: Health Care
subject: 111707 Family Care
subject: FOS: Health sciences

description: This is the immediate postabortion care interview tool (Interview PAC 1) for Jhpiego's Post Pregnancy Family Planning Choices (PPFP Choices) operations research study in Kenya and Indonesia. Included are the English, Bahasa, Kiswahili and Kimeru versions of the recruitment and consent forms as well as the interview tools.
Real-Valued Charged Fields and Interpretation of Quantum Mechanics
Creators: name: Akhmeteli, A. M.
Publisher: name: arXiv
Year: 2005
Subjects: subject: Quantum Physics (quant-ph)
subject: FOS: Physical sciences

description: Schroedinger (Nature, v.169, p.538 (1952)) demonstrated that, contrary to the widespread belief, charged particles may be described by real fields. Therefore the sets of solutions with real-valued charged fields are considered in the present work for some versions of (non-second-quantized) quantum electrodynamics (for Dirac spinors "real-valued" is understood as "satisfying the Majorana condition"). In some of the versions any solution may be obtained from a solution from those sets by a gauge transform. The solutions from those sets have common features suggesting a natural interpretation along the lines of the Bohm interpretation, but no quantum potentials arise, and it is the electromagnetic field, not the wave function, that plays the role of the guiding field.
description: 5 pages, no figures
Driven classical diffusion with strong correlated disorder
Creators: name: Pryadko, Leonid P.
name: Lin, Jing-Xian
Publisher: name: arXiv
Year: 2004
Subjects: subject: Disordered Systems and Neural Networks (cond-mat.dis-nn)
subject: FOS: Physical sciences

description: We analyze one-dimensional motion of an overdamped classical particle in the presence of external disorder potential and an arbitrary driving force F. In thermodynamical limit the effective force-dependent mobility mu(F) is self-averaging, although the required system size may be exponentially large for strong disorder. We calculate the mobility mu(F) exactly, generalizing the known results in linear response (weak driving force) and the perturbation theory in powers of the disorder amplitude. For a strong disorder potential with power-law correlations we identify a non-linear regime with a prominent power-law dependence of the logarithm of mu(F) on the driving force.
description: 4 pages, 2 figures included
Piezofibre composite transducers for next generation 3D USCT
Creators: name: Zapf, Michael
name: Hohlfeld, K.
name: Pfistner, P.
name: Imbracio Liberman, C.
name: Van Dongen, Koen W.A.
name: Gemmeke, Hartmut
name: Ruiter, Nicole V.
name: Michaelis, A.
name: Gebhardt, S.
Publisher: name: KIT Scientific Publishing
Year: 2018

description: At the Karlsruhe Institue of Technology (KIT), a 3D-Ultrasound Computer Tomography (3D-USCT) medical imaging system for early breast cancer detection is currently developed. With the next generation of 3D-USCT 2.5, the current region of interest (ROI) of 10 x 10 x 10 cm³ shall be increased to 20 x 20 x 20 cm³ to allow reliable imaging results also for bigger female breasts. Therefore, the opening angle (OA) of the future transducers should be increased to approx. 60 ° at 3 dB while other characteristics such as bandwidth (BW) and resonance frequency should be preserved or even improved. Based on Fraunhofer IKTS Piezofibre composites utilized for transducer production, an optimization is performed on piezoelectric sensor geometry and size, type and structure of matching and backing layer and interconnection technology of the several parts of the transducer