Does Pig Density Matter for the Choice of Control Strategies in Classical Swine Fever Epidemic?

This paper examines the importance of pig population density in the area of an outbreak of CSF for the spread of the disease and the choice of control measures. A sector-level market and trade model and a spatial, stochastic, dynamic epidemiological simulation model for the Netherlands were used. Outbreaks in sparsely and densely populated areas were compared under four different control strategies and with two alternative trade assumptions. Results indicate that the control strategy required by current EU legislation is enough to eradicate an epidemic starting in an area with sparse pig population. By contrast, additional control measures are necessary if the outbreak begins in an area with high pig population density. The economic consequences of using preventive slaughter rather than emergency vaccination as an additional control measure depend strongly on the reactions of trading partners. Reducing the number of animal movements significantly reduces the size and length of epidemics in areas with high pig density.Classical Swine Fever epidemics, pig population density, animal transport, emergency vaccination, preventive slaughter, the Netherlands, Livestock Production/Industries,

Grandparent Caregivers’ Perceptions and Lived Experiences: Their Health and Wellbeing, Access to Health and State of Health Services in Zimbabwe

The study explored the perceptions and lived experiences of self-rated health, access to health, and state of health services for grandparent caregivers in Zimbabwe. In–depth interviews using semi-structured interview guides were carried out to elicit perceptions of lived experiences from grandparent caregivers (N=31; Mean age= 65.7; SD= 10.7). The data was thematically analysed and the software Nvivo 10 was used to help categorize emergent themes. The study found that grandparent caregivers experienced multiple chronic and complex self-rated health conditions (e.g., High blood pressure (HBP), arthritis, diabetes, hypertension, back pain, and heart problems), which influenced their health and Quality of Life (QOL). They perceived health services as inaccessible without medical insurance and provision of health services in Zimbabwe as appalling and prohibitive, particularly in rural areas. The negative perceptions of health services impacted caregivers’ willingness to seek the services when needed. Some of the caregivers resorted to traditional healers and religious leaders’ services as alternatives to conventional health services for coping with poor physical and mental health. The high prevalence of self-reported chronic illnesses and the crisis in the health sector was lamented by most grandparent caregivers, indicating the need for access to quality health care and/or services, medical insurance, and social protection services

Electron degeneracy and intrinsic magnetic properties of epitaxial Nb:SrTiO3_3 thin-films controlled by defects

We report thermoelectric power experiments in e-doped thin films of SrTiO$_3$ (STO) which demonstrate that the electronic band degeneracy can be lifted through defect management during growth. We show that even small amounts of cationic vacancies, combined with epitaxial stress, produce a homogeneous tetragonal distortion of the films, resulting in a Kondo-like resistance upturn at low temperature, large anisotropic magnetoresistance, and non-linear Hall effect. Ab-initio calculations confirm a different occupation of each band depending on the degree of tetragonal distortion. The phenomenology reported in this paper for tetragonally distorted e-doped STO thin films, is similarto that observed in LaAlO$_3$/STO interfaces and magnetic STO quantum wells.Comment: 5 pages, 5 figure

Magnetic behavior of NiCu nanowire arrays: Compositional, geometry and temperature dependence

Arrays of Ni100-xCux nanowires ranging in composition 0¿=¿x¿=¿75, diameter from 35 to 80¿nm, and length from 150¿nm to 28¿µm have been fabricated by electrochemical co-deposition of Ni and Cu into self-ordered anodic aluminum oxide membranes. As determined by X-ray diffraction and Transmission Electron Microscopy, the crystalline structure shows fcc cubic symmetry with [111] preferred texture and preferential Ni or Cu lattice depending on the composition. Their magnetic properties such as coercivity and squareness have been determined as a function of composition and geometry in a Vibrating Sample Magnetometer in the temperature range from 10 to 290¿K for applied magnetic fields parallel and perpendicular to the nanowires axis. Addition of Cu into the NiCu alloy up to 50% enhances both parallel coercivity and squareness. For the higher Cu content, these properties decrease and the magnetization easy axis becomes oriented perpendicular to the wires. In addition, coercivity and squareness increase by decreasing the diameter of nanowires which is ascribed to the increase of shape anisotropy. The temperature dependent measurements reflect a complex behavior of the magnetic anisotropy as a result of energy contributions with different evolution with temperature

Structural and magnetic properties of amorphous Co-W alloyed nanoparticles

18 páginas, 20 figuras, 4 tablas.-- PACS number(s): 75.75.Fk, 75.50.Kj, 75.30.Gw, 61.46.Df.-- et al.et al.W-capped Co nanoparticles dispersed in an alumina matrix are studied by means of high-resolution transmission electron microscopy, extended x-ray absorption fine structure, SQUID-based magnetic measurements, dc magnetization, ac magnetic susceptibility, and x-ray magnetic circular dichroism. Results show the formation of amorphous Co-W alloy nanoparticles, the magnetic properties of which are modified by the amount of W or Co present in the samples. The average Co magnetic moment depends on the number of W atoms surrounding it. Co-W particles show superparamagnetic behavior and are described as an array of noninteracting particles with random anisotropy axes and an average moment per particle proportional to the particle volume and to the average Co moment for each alloy composition. Values of the magnetic anisotropy constant of the particles are on the order of 106 erg/cm3, higher than that of bulk Co. Evidence of short-range ordering within each amorphous particle is found that provides insight of the origin of their magnetic anisotropy.The financial support of MICINN-FEDER MAT08/1077 and Aragonese IMANA project is acknowledged. A.I.F. acknowledges a CSIC JAE2008-Predoc grant.Peer reviewe

Randomized Extended Kaczmarz for Solving Least-Squares

We present a randomized iterative algorithm that exponentially converges in expectation to the minimum Euclidean norm least squares solution of a given linear system of equations. The expected number of arithmetic operations required to obtain an estimate of given accuracy is proportional to the square condition number of the system multiplied by the number of non-zeros entries of the input matrix. The proposed algorithm is an extension of the randomized Kaczmarz method that was analyzed by Strohmer and Vershynin.Comment: 19 Pages, 5 figures; code is available at https://github.com/zouzias/RE

The Transcription Factor NURR1 Exerts Concentration-Dependent Effects on Target Genes Mediating Distinct Biological Processes

The transcription factor NURR1 plays a pivotal role in the development and maintenance of neurotransmitter phenotype in midbrain dopamine neurons. Conversely, decreased NURR1 expression is associated with a number of dopamine-related CNS disorders, including Parkinson’s disease and drug addiction. In order to better understand the nature of NURR1-responsive genes and their potential roles in dopamine neuron differentiation and survival, we used a human neural cellular background (SK-N-AS cells) in which to generate a number of stable clonal lines with graded NURR1 gene expression that approximated that seen in DA cell-rich human substantia nigra. Gene expression profiling data from these NURR1-expressing clonal lines were validated by quantitative RT-PCR and subjected to bioinformatic analyses. The present study identified a large number of NURR1-responsive genes and demonstrated the potential importance of concentration-dependent NURR1 effects in the differential regulation of distinct NURR1 target genes and biological pathways. These data support the promise of NURR1-based CNS therapeutics for the neuroprotection and/or functional restoration of DA neurons

Efficient Triangle Counting in Large Graphs via Degree-based Vertex Partitioning

The number of triangles is a computationally expensive graph statistic which is frequently used in complex network analysis (e.g., transitivity ratio), in various random graph models (e.g., exponential random graph model) and in important real world applications such as spam detection, uncovering of the hidden thematic structure of the Web and link recommendation. Counting triangles in graphs with millions and billions of edges requires algorithms which run fast, use small amount of space, provide accurate estimates of the number of triangles and preferably are parallelizable. In this paper we present an efficient triangle counting algorithm which can be adapted to the semistreaming model. The key idea of our algorithm is to combine the sampling algorithm of Tsourakakis et al. and the partitioning of the set of vertices into a high degree and a low degree subset respectively as in the Alon, Yuster and Zwick work treating each set appropriately. We obtain a running time $O \left(m + \frac{m^{3/2} \Delta \log{n}}{t \epsilon^2} \right)$ and an $\epsilon$ approximation (multiplicative error), where $n$ is the number of vertices, $m$ the number of edges and $\Delta$ the maximum number of triangles an edge is contained. Furthermore, we show how this algorithm can be adapted to the semistreaming model with space usage $O\left(m^{1/2}\log{n} + \frac{m^{3/2} \Delta \log{n}}{t \epsilon^2} \right)$ and a constant number of passes (three) over the graph stream. We apply our methods in various networks with several millions of edges and we obtain excellent results. Finally, we propose a random projection based method for triangle counting and provide a sufficient condition to obtain an estimate with low variance.Comment: 1) 12 pages 2) To appear in the 7th Workshop on Algorithms and Models for the Web Graph (WAW 2010

Authors' Response

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97166/1/jfo12080.pd

Separation of realized ecological niche axes among sympatric tilefishes provides insight into potential drivers of co-occurrence in the NW Atlantic

Golden and Blueline Tilefish (Lopholatilus chamaeleonticeps and Caulolatilus microps) are keystone taxa in northwest (NW) Atlantic continental shelf-edge environments due to their biotic (trophic-mediated) and abiotic (ecosystem engineering) functional roles combined with high-value fisheries. Despite this importance, the ecological niche dynamics (i.e., those relating to trophic behavior and food-web interactions) of these sympatric species are poorly understood, knowledge of which may be consequential for maintaining both ecosystem function and fishery sustainability. We used stable isotope ratios of carbon (δ13C) and nitrogen (δ15N) to build realized ecological niche hypervolumes to serve as proxies for diet and production use patterns of L. chamaeleonticeps and C. microps. We hypothesized that: (a) species exhibit ontogenetic shifts in diet and use of production sources; (b) species acquire energy from spatially distinct resource pools that reflect a sedentary life-history and differential use of the continental shelf-edge; and (c) species exhibit differentiation in one or more measured niche axes. We found evidence for ontogenetic shifts in diet (δ15N) but not production source (δ13C) in both species, suggesting a subtle expansion of measured ecological niche axes. Spatial interpolation of stable isotope ratios showed distinct latitudinal gradients; for example, individuals were 13C enriched in northern and 15N enriched in southern regions, supporting the assertion that tilefish species acquire energy from regional resource pools. High isotopic overlap was observed among species (≥82%); however, when hypervolumes included depth and region of capture, overlap among species substantially decreased to overlap estimates of 15%–77%. This suggests that spatial segregation could alleviate potential competition for resources among tilefish species inhabiting continental shelf-edge environments. Importantly, our results question the consensus interpretation of isotopic overlap estimates as representative of direct competition among species for shared resources or habitats, instead identifying habitat segregation as a possible mechanism for coexistence of tilefish species in the NW Atlantic