2,183 research outputs found
Ventilation of small livestock trailers
A large number of livestock is transported to market in small box trailers. The welfare
of animals transported in this way is now assuming greater importance with the onset
of tougher EU legislation. This paper presents the first study into the ventilation of
small livestock trailers using experimental and computational methods. Wind tunnel
studies, using a 1/7th scale model, highlight the important influence of the towing
vehicle and trailer design on the airflow within the trailer. Detailed CFD analysis
agrees well with the wind tunnel data and offers the ability to assess the impact of
design changes
A Linear-Nonlinear Formulation of Einstein Equations for the Two-Body Problem in General Relativity
A formulation of Einstein equations is presented that could yield advantages
in the study of collisions of binary compact objects during regimes between
linear-nonlinear transitions. The key idea behind this formulation is a
separation of the dynamical variables into i) a fixed conformal 3-geometry, ii)
a conformal factor possessing nonlinear dynamics and iii) transverse-traceless
perturbations of the conformal 3-geometry.Comment: 7 pages, no figure
Early decomposition in visual word recognition: Dissociating morphology, form, and meaning
The role of morphological, semantic, and form-based factors in the early stages of visual word recognition was investigated across different SOAs in a masked priming paradigm, focusing on English derivational morphology. In a first set of experiments, stimulus pairs co-varying in morphological decomposability and in semantic and orthographic relatedness were presented at three SOAs (36, 48, and 72 ms). No effects of orthographic relatedness were found at any SOA. Semantic relatedness did not interact with effects of morphological decomposability, which came through strongly at all SOAs, even for pseudo-suffixed pairs such as archer-arch. Derivational morphological effects in masked priming seem to be primarily driven by morphological decomposability at an early stage of visual word recognition, and are independent of semantic factors. A second experiment reversed the order of prime and target (stem-derived rather than derived-stem), and again found that morphological priming did not interact with semantic relatedness. This points to an early segmentation process that is driven by morphological decomposability and not by the structure or content of central lexical representations
Investigating hookworm genomes by comparative analysis of two Ancylostoma species
Background
Hookworms, infecting over one billion people, are the mostly closely related major human parasites to the model nematode Caenorhabditis elegans. Applying genomics techniques to these species, we analyzed 3,840 and 3,149 genes from Ancylostoma caninum and A. ceylanicum.
Results
Transcripts originated from libraries representing infective L3 larva, stimulated L3, arrested L3, and adults. Most genes are represented in single stages including abundant transcripts like hsp-20 in infective L3 and vit-3 in adults. Over 80% of the genes have homologs in C. elegans, and nearly 30% of these were with observable RNA interference phenotypes. Homologies were identified to nematode-specific and clade V specific gene families. To study the evolution of hookworm genes, 574 A. caninum / A. ceylanicum orthologs were identified, all of which were found to be under purifying selection with distribution ratios of nonsynonymous to synonymous amino acid substitutions similar to that reported for C. elegans / C. briggsae orthologs. The phylogenetic distance between A. caninum and A. ceylanicum is almost identical to that for C. elegans / C. briggsae.
Conclusion
The genes discovered should substantially accelerate research toward better understanding of the parasites' basic biology as well as new therapies including vaccines and novel anthelmintics
Background field boundary conditions for affine Toda field theories
Classical integrability is investigated for affine Toda field theories in the
presence of a constant background tensor field. This leads to a further set of
discrete possibilities for integrable boundary conditions depending upon the
time-derivative of the fields at the boundary but containing no free parameters
other than the bulk coupling constant.Comment: 21 pages, harvma
Assembling a speciesâarea curve through colonization, speciation and humanâmediated introduction
AimThe fundamental biogeographical processes of colonization, speciation and extinction shape island biotas in spaceâtime. On oceanic islands, area and isolation affect these processes and resulting biodiversity patterns. In the Anthropocene, a new humanâmediated colonization dynamic is altering insular ecosystems worldâwide. Here, we test predictions about the roles of archipelago area and isolation in structuring ant diversity patterns through effects on both natural and anthropogenic biogeographical processes.LocationTropical Pacific islands.MethodsWe compiled a comprehensive data set of ant faunal compositions across tropical Pacific archipelagos. Using regression analysis we evaluated the bivariate and interactive effects of area and isolation on the number of colonizing lineages, native species, endemic species, exotic species and total richness in the archipelago.ResultsThere is a strong speciesâarea effect and a much more modest isolation effect on total ant species richness across the Pacific archipelagos. The number of colonizing lineages of each archipelago is strongly driven by the isolation of the archipelago. Endemic species are present in large archipelagos of low and intermediate isolation. The most remote archipelagos are nearly devoid of endemic lineages and their ant faunas are largely composed of Pacific Tramp species and exotics brought from outside the Pacific region.Main conclusionsThe prominent speciesâarea curve in Pacific ants emerged over time through multiple processes. The colonization of lineages is determined primarily by isolation, with few or no lineages reaching remote archipelagos. Cladogenesis mediates the isolation effect and increases the area effect through the differential radiation of lineages in large archipelagos. In the Anthropocene, the assembly of the speciesâarea relationship has accelerated dramatically through humanâmediated colonization. Overall, our results support a view that speciesâarea curves reflect regulating limits on species richness that scale with area, but that multiple biogeographical processes can occur to achieve these limits.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136723/1/jbi12884.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136723/2/jbi12884_am.pd
Spectroscopic and Photometric Study of the Contact Binary BO CVn
We present the results of the study of the contact binary system BO CVn. We
have obtained physical parameters of the components based on combined analysis
of new, multi-color light curves and spectroscopic mass ratio. This is the
first time the latter has been determined for this object. We derived the
contact configuration for the system with a very high filling factor of about
88 percent. We were able to reproduce the observed light curve, namely the flat
bottom of the secondary minimum, only if a third light has been added into the
list of free parameters. The resulting third light contribution is significant,
about 20-24 percent, while the absolute parameters of components are: M1=1.16,
M2=0.39, R1=1.62 and R2=1.00 (in solar units). The O-C diagram shows an upward
parabola which, under the conservative mass transfer assumption, would
correspond to a mass transfer rate of dM/dt = 6.3 \times 10-8M\odot/yr, matter
being transferred from the less massive component to the more massive one. No
cyclic, short-period variations have been found in the O-C diagram (but
longer-term variations remain a possibility)Comment: 16 pages, 5 figures, 5 tables, accepted for publication by New
Astronom
Time mating guinea pigs by monitoring changes to the vaginal membrane throughout the estrus cycle and with ultrasound confirmation
One of the greatest challenges to the development and implementation of pregnancy therapeutics is the ability to rigorously test treatments in clinically relevant animal models. Guinea pigs offer a unique advantage in studying the placenta, fetal development, and reproductive health as they have similar developmental milestones to humans, both throughout gestation and following birth. Tracking the guinea pig estrus cycle is imperative to ensuring appropriately timed mating and can be performed by monitoring the guinea pig vaginal membrane. Here, we describe a methodology to efficiently and accurately time mate guinea pigs, and provide a picture representation of changes to the guinea pig vaginal membrane throughout the estrus cycle. Utilization of this monitoring enabled a 100% pregnancy success rate on the first mating attempt in a cohort of five guinea pigs. This approach, along with early pregnancy ultrasounds as a secondary method to confirm pregnancy, offers a reliable approach to timed mating in the guinea pig
Steering of a Bosonic Mode with a Double Quantum Dot
We investigate the transport and coherence properties of a double quantum dot
coupled to a single damped boson mode. Our numerically results reveal how the
properties of the boson distribution can be steered by altering parameters of
the electronic system such as the energy difference between the dots.
Quadrature amplitude variances and the Wigner function are employed to
illustrate how the state of the boson mode can be controlled by a stationary
electron current through the dots.Comment: 10 pages, 6 figures, to appear in Phys. Rev.
Separate and combined effects of oligofructose and inulin on post-weaning coli bacillosis and weight gain: a preliminary study
Trends for a reduction in the use of dietary antibiotic growth promoters have caused increased interest in the use of alternative feed additives to maintain 'gut health' after weaning. Oligofructose and inulin are 'prebiotic' fructan-containing carbohydrates purported to enhance 'gut health' in newly-weaned pigs by altering microbial diversity (Konstantinov, et al., 2003). However, their effects using a challenge model of post-weaning colibacillosis (PWC) have never been examined. The aim of the present study was to compare the separate and combined effects of oligofructose and inulin supplementation on the occurrence of diarrhoea and the weight performance in piglets experimentally challenged with enterotoxigenic E. coli (ETEC)
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