1,199 research outputs found
The asymmetry of the dimension 2 gluon condensate: the zero temperature case
We provide an algebraic study of the local composite operators A_\mu
A_\nu-\delta_{\mu\nu}/d A^2 and A^2, with d=4 the spacetime dimension. We prove
that these are separately renormalizable to all orders in the Landau gauge.
This corresponds to a renormalizable decomposition of the operator A_\mu A_\nu
into its trace and traceless part. We present explicit results for the relevant
renormalization group functions to three loop order, accompanied with various
tests of these results. We then develop a formalism to determine the zero
temperature effective potential for the corresponding condensates, and recover
the already known result for \neq 0, together with <A_\mu
A_\nu-\delta_{\mu\nu}/d A^2>=0, a nontrivial check that the approach is
consistent with Lorentz symmetry. The formalism is such that it is readily
generalizable to the finite temperature case, which shall allow a future
analytical study of the electric-magnetic symmetry of the condensate,
which received strong evidence from recent lattice simulations by Chernodub and
Ilgenfritz, who related their results to 3 regions in the Yang-Mills phase
diagram.Comment: 25 page
A review of color vision in white-tailed deer
A better understanding of the color vision abilities of white-tailed deer (Odocoileus virginianus) helps to determine how these animals interpret their environment. We review and summarize the literature related to the color vision abilities of white-tailed deer. Physiological measurements using advanced techniques such as molecular genetics, electroretinography, and electron microscopy have demonstrated conclusively that whitetailed deer possess the anatomical requisites for color vision. Operant conditioning techniques employed in pen studies using trained cervids confirm that deer see color. The eyes of white-tailed deer are characterized by 3 classes of photopigments: a short-wavelengthsensitive cone mechanism, a middle-wavelength-sensitive cone mechanism, and a short wavelength- sensitive rod pigment. The number and distribution of rod, and cones in the retina, augmented by adaptations of the eye, give white-tailed deer high visual sensitivity and visual acuity in light and darkness. During the day deer discriminate colors in the range blue to yellow-green and can also distinguish longer (orange and red) wavelengths. At night deer see color in the blue to blue-green range, although the moderately wide spectral sensitivity of rods permits some discrimination of longer wavelengths. Rods serve a discriminatory role in color vision, especially at low to moderate illumination levels. Benefits of color vision to deer include the ability to discriminate between plant species and parts and enhanced predator-detection capabilities. This information can be used to define methods of resolving deer-human conflicts and provide insight to deer researchers, photographers, and hunters on how to he more inconspicuous to their subject
Fencing Methods to Reduce Deer Damage
The white-tailed deer (Odocoifeus virginianus) may cause more damage than any other wildlife species. Deer damage occurs in various forms including crop production, automobile accidents, aviation collisions on runways, disease transmission, degradation of natural ecosystems, and destruction of ornamental plantings. One practical method of controlling deer damage is through the use of exclusionary fencing. White-tailed deer are challenging to exclude as they are able to jump 3.0-m fences or fit through spaces \u3e 20 cm wide. Some deer problems (disease outbreaks, aircraft runways, and busy highways in deer migration corridors) may necessitate the installation of effective fencing no matter what the cost. Fences most often installed to control white-tailed deer damage include, but are not limited to, many varieties and types of wire mesh, plastic mesh, high-tensile steel wire, and electric fence. We have reviewed scientific literature on fencing to compare fence designs and methods to predict which are best suited for excluding deer under a variety of conditions.
In situations where a nearly impenetrable, low maintenance, long-life fence is needed, a 3.0-3 64 m-high wire mesh fence is the best option. If complete exclusion is not a necessity and fence cost is an issue, a multi-strand, electrified, high-tensile steel wire fence may be sufficient. For seasonal protection, an affordable, easily installed, peanut butter fence may be adequate. Each fencing application will require consideration of different factors for determining the most appropriate fence, requiring a thorough comparison of available options to assist in the decision making process.
The most important considerations for determining the best fence for a specific application include: level of protection desired from the fence, deer\u27s ability to penetrate different fence designs, motivation to penetrate a fence, costs associated with a fence, and possible negative effects of erecting a fence. Fencing may be only part of the answer to a deer damage issue. An integrated management approach may increase the overall efficacy of any individual damage reduction method, including fencing.
With abundant white-tailed deer populations, recent disease outbreaks, increasing vehicle collisions, and increased urbanization, there is an increasing need for effective deer-damage management tools. There are many research needs in the area of wildlife exclusion. Few rigorous tests of the efficacy of different fence designs have been conducted. Efficacy levels of any specific fence design are difficult to establish due to the multitude of interacting variables determining how an animal will respond to a particular fence design. Most, if not all, of the scientific testing conducted to date has been directed at excluding animals. However, means of confining captive deer are also of importance
Use and selection of sleeping sites by proboscis monkeys, Nasalislarvatus, along the Kinabatangan River, Sabah, Malaysia
The choice of a sleeping site is crucial for primates and may influence their survival. In this study, we investigated several tree characteristics influencing the sleeping site selection by proboscis monkeys (Nasalis larvatus) along Kinabatangan River, in Sabah, Malaysia. We identified 81 sleeping trees used by one-male and all-male social groups from November 2011 to January 2012. We recorded 15 variables for each tree. Within sleeping sites, sleeping trees were taller, had a larger trunk, with larger and higher first branches than surrounding trees. The crown contained more mature leaves, ripe and unripe fruits but had vines less often than surrounding trees. In addition, in this study, we also focused on a larger scale, considering sleeping and non-sleeping sites. Multivariate analyses highlighted a combination of 6 variables that revealed the significance of sleeping trees as well as surrounding trees in the selection process. During our boat surveys, we observed that adult females and young individuals stayed higher in the canopy than adult males. This pattern may be driven by their increased vulnerability to predation. Finally, we suggest that the selection of particular sleeping tree features (i.e. tall, high first branch) by proboscis monkeys is mostly influenced by antipredation strategies
Predicting spatial spread of rabies in skunk populations using surveillance data reported by the public
Background:
Prevention and control of wildlife disease invasions relies on the ability to predict spatio-temporal dynamics and understand the role of factors driving spread rates, such as seasonality and transmission distance. Passive disease surveillance (i.e., case reports by public) is a common method of monitoring emergence of wildlife diseases, but can be challenging to interpret due to spatial biases and limitations in data quantity and quality.
Methodology/Principal findings:
We obtained passive rabies surveillance data from dead striped skunks (Mephitis mephitis) in an epizootic in northern Colorado, USA. We developed a dynamic patch-occupancy model which predicts spatio-temporal spreading while accounting for heterogeneous sampling. We estimated the distance travelled per transmission event, direction of invasion, rate of spatial spread, and effects of infection density and season. We also estimated mean transmission distance and rates of spatial spread using a phylogeographic approach on a subsample of viral sequences from the same epizootic. Both the occupancy and phylogeographic approaches predicted similar rates of spatio-temporal spread. Estimated mean transmission distances were 2.3 km (95% Highest Posterior Density (HPD95): 0.02, 11.9; phylogeographic) and 3.9 km (95% credible intervals (CI95): 1.4, 11.3; occupancy). Estimated rates of spatial spread in km/year were: 29.8 (HPD95: 20.8, 39.8; phylogeographic, branch velocity, homogenous model), 22.6 (HPD95: 15.3, 29.7; phylogeographic, diffusion rate, homogenous model) and 21.1 (CI95: 16.7, 25.5; occupancy). Initial colonization probability was twice as high in spring relative to fall.
Conclusions/Significance:
Skunk-to-skunk transmission was primarily local (< 4 km) suggesting that if interventions were needed, they could be applied at the wave front. Slower viral invasions of skunk rabies in western USA compared to a similar epizootic in raccoons in the eastern USA implies host species or landscape factors underlie the dynamics of rabies invasions. Our framework provides a straightforward method for estimating rates of spatial spread of wildlife diseases
Evaluation of an animal-activated scarecrow and a monofilament fence for reducing deer use of soybean fields
We measured the efficacy of an animal-activated scarecrow (AAS) and a 5-strand monofilament fence (MF) at reducing white-tailed deer (Odocoileus virginianus) use of 0.4-ha soybean plots in Missouri, USA. Our study design consisted of 9 soybean plots; 3 served as controls, 3 were surrounded by an MF, and 3 were surrounded by an AAS. Data collected for each protected plot included soybean height and weight taken from within and immediately adjacent to 10 unprotected, equally spaced 1 -m2 exclosures. A measure of deer use for each plot was collected with video cameras. A mixed-effects analysis of variance (ANOVA) indicated that heights of protected and unprotected soybean plants were significantly different for MF plots (F2 =93.6, P=0.01) and controls (F2 =47.6, P= 0.02) but not different for AAS plots (F2=2.16, P=0.272). Soybean plants in AAS plots were heavier than those from MF or control plots (F2 =10.2, P=0.01). Plant weight differences in protected and unprotected areas for AAS plots were less than those from MF plots (t6=2.55, P=0.04) or control plots (t6=4.46, P=0.004). Plant weight differences between MF and control plots were marginally significant (t6= 1.192, P=0.10). Deer spent less time in AAS plots than MF (t6=2.55, P=0.041 or control plots (t6=2.55, P= 0.01). Scarecrow activations increased over time in all 3 AAS plots (all 95% confidence intervals \u3e0), suggesting that deer were habituating to the devices. We suggest that AAS may be useful for short-term deterrence of deer from small areas
Coyote-Activated Frightening Devices for Reducing Sheep Predation on Open Range
Domestic sheep ranching is an important agricultural industry in the United States and coyote (Canis latrans) depredation on lambs and ewes continues to challenge ranchers and agencies responsible for protecting sheep. Lethal methods used in controlling coyote depredation include aerial gunning, toxicants, trapping, and calling and shooting. Nonlethal methods include frightening devices, fences, livestock protection animals, and stringent husbandry practices. Ranchers and agencies responsible for controlling coyote depredation need frightening devices that are more effective than those currently available. We describe a field evaluation of 2 animal-activated frightening devices: an acoustic device and an acoustic device with a pop-up scarecrow and strobe light. We conducted the evaluation on open range in western Wyoming during the lambing period. No coyote kills were reported during 6,087 sheepnights at 3 sites protected by the acoustic devices or during 6,598 sheepnights at 3 sites protected by the acoustic scarecrow devices. Our devices show promise for reducing predation during the lambing period and merit further evaluation
Intraoperative Organ Motion Models with an Ensemble of Conditional Generative Adversarial Networks
In this paper, we describe how a patient-specific, ultrasound-probe-induced
prostate motion model can be directly generated from a single preoperative MR
image. Our motion model allows for sampling from the conditional distribution
of dense displacement fields, is encoded by a generative neural network
conditioned on a medical image, and accepts random noise as additional input.
The generative network is trained by a minimax optimisation with a second
discriminative neural network, tasked to distinguish generated samples from
training motion data. In this work, we propose that 1) jointly optimising a
third conditioning neural network that pre-processes the input image, can
effectively extract patient-specific features for conditioning; and 2)
combining multiple generative models trained separately with heuristically
pre-disjointed training data sets can adequately mitigate the problem of mode
collapse. Trained with diagnostic T2-weighted MR images from 143 real patients
and 73,216 3D dense displacement fields from finite element simulations of
intraoperative prostate motion due to transrectal ultrasound probe pressure,
the proposed models produced physically-plausible patient-specific motion of
prostate glands. The ability to capture biomechanically simulated motion was
evaluated using two errors representing generalisability and specificity of the
model. The median values, calculated from a 10-fold cross-validation, were
2.8+/-0.3 mm and 1.7+/-0.1 mm, respectively. We conclude that the introduced
approach demonstrates the feasibility of applying state-of-the-art machine
learning algorithms to generate organ motion models from patient images, and
shows significant promise for future research.Comment: Accepted to MICCAI 201
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