977 research outputs found
Mycoplasma Mastitis in Dairy Cattle
Mastitis is defined as inflammation of the mammary gland, usually due to microbial infection. Many organisms have been known to cause mastitis including bacteria, fungi, and yeast. Mastitis is the most economically important disease of the dairy industry, the condition has been estimated to cause as much as two billion dollars in lost income for United States dairy producers at a cost of $181 per cow per year. The biggest losses are due to lowered production, but discarded milk, drugs, veterinary costs, and premature culling also contribute to the losses. More than 130 different microorganisms have been isolated from the mammary gland of the bovine with the majority of infections due to staphylococci, streptococci, and coliforms. However, mycoplasmas have begun to cause significant problems in some dairies. The first reported cases of mycoplasma mastitis were in Europe in 1960. Since that time it has been found all around the world, including the United States. Traditionally, California was most affected, but the disease has now become a problem across the entire country
Elimination of IR/UV via Gravity in Noncommutative Field Theory
Models of particle physics with Noncommutative Geometry (NCG) generally
suffer from a manifestly non-Wilsonian coupling of infrared and ultraviolet
degrees of freedom known as the "IR/UV Problem" which would tend to compromise
their phenomenological relevance. In this Letter we explicitly show how one may
remedy this by coupling NCG to gravity. In the simplest scenario the Lagrangian
gets multiplied by a nonconstant background metric; in theory the
theorem that is no longer true
and the field propagator gets modified by a factor which depends on both NCG
and the variation of the metric. A suitable limit of this factor as the
propagating momentum gets asymptotically large then eradicates the IR/UV
problem. With gravity and NCG coupled to each other, one might expect
anti-symmetric components to arise in the metric. Cosmological implications of
such are subsequently discussed.Comment: 6 pages; MPLA versio
Peracute Toxic Coliform Mastitis
The incidence of coliform mastitis has been on the increase since a serious effort has been made to eliminate Streptococcus agalactia and Staphylacoccus aureus mammary infections in dairy herds throughout the U.S. As somatic cell counts decrease in dairy cows, they tend to be more susceptible to coliform mastitis. It is likely that this trend will continue as long as stringent controls are being placed on somatic cell levels and premiums are being offered for better quality milk
Bovine Anaplasmosis: An Overview
Bovine Anaplasmosis is an infectious disease of adult cattle caused by the hemotrophic rickettsial parasite Anaplasma marginale. Cattle of all ages may become infected with Anaplasma marginale, but clinical disease increases in severity with age. Anaplasmosis is rarely observed in calveslessthan sixmonths of age. Cattle over three years of age are most susceptible and have the highest mortality rate (30-50%). Anaplasmosis is a cyclical disease with outbreaks occurring every five to seven years. The American National Cattlemen\u27s Association has considered anaplasmosis as a major disease problem with annual losses and disease control estimated to be $300 millio
Enhancement of the ferromagnetic order of graphite after sulphuric acid treatment
We have studied the changes in the ferromagnetic behavior of graphite powder
and graphite flakes after treatment with diluted sulphuric acid. We show that
this kind of acid treatment enhances substantially the ferromagnetic
magnetization of virgin graphite micrometer size powder as well as in graphite
flakes. The anisotropic magnetoresistance (AMR) amplitude at 300 K measured in
a micrometer size thin graphite flake after acid treatment reaches values
comparable to polycrystalline cobalt.Comment: 3.2 pages, 4 figure
Value-added Teacher Estimates as Part of Teacher Evaluations: Exploring the Effects of Data and Model Specifications on the Stability of Teacher Value-added Scores
In this study we explored the effects of statistical controls, single versus multiple cohort models, and student sample size on the stability of teacher value-added estimates (VAEs). We estimated VAEs for all 5th grade mathematics teachers in a large urban district by fitting two level mixed models using four cohorts of student data. We found that student sample size had the largest effect on changes in teachersâ relative standing and designation into performance groups, while control variables affected VAEs only minimally. However, we also found that teacher VAEs showed a fair degree of stability; year-to-year correlations ranged between .62 and .66, and changes in teacher effectiveness systematically varied by teacher experience, with beginning teachers showing the largest improvements over the four years under study. Our results suggest that some model specifications are likely to produce teacher value-added scores that can reflect meaningful differences in teachers while we also found that other models might produce VAEs that might be unreliable. Â
THREE-DIMENSIONAL ASSESSMENT OF ON WATER ROWING TECHNIQUE: A METHODOLOGICAL STUDY
The analysis of rowing technique in training or competitive environments has been a challenge to biomechanists for some time now. Typically, two-dimensional assessments are carried out with fixed cameras mounted on-land next to a rowing course (Hay 1993) or by handheld cameras from an accompanying boat. Three-dimensional technique analysis were only presented for athletes rowing on an ergometer in a laboratory environment (Hofmijster et al. 2007). The purpose of this study was to develop and validate a system for three-dimensional kinematic analyses of on water rowing
Theory of Exciton Migration and Field-Induced Dissociation in Conjugated Polymers
The interplay of migration, recombination, and dissociation of excitons in
disordered media is studied theoretically in the low temperature regime. An
exact expression for the photoluminescence spectrum is obtained. The theory is
applied to describe the electric field-induced photoluminescence-quenching
experiments by Kersting et al. [Phys. Rev. Lett. 73, 1440 (1994)] and Deussen
et al. [Synth. Met. 73, 123 (1995)] on conjugated polymer systems. Good
agreement with experiment is obtained using an on-chain dissociation mechanism,
which implies a separation of the electron-hole pair along the polymer chain.Comment: 4 pages, RevTeX, 2 Postscript figure
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