467 research outputs found
Factors affecting the development of laryngeal chondritis in sheep.
Historic data (from 2005 to 2011) were collected and analysed from four flocks of pedigree Texel sheep in Ceredigion, West Wales and were used to investigate a range of factors associated with death due to laryngeal chondritis (n=82) relative to all animals (n=2826) removed from the flocks, either due to death from other causes or as part of routine animal husbandry (e.g. sale of livestock to other farms, or for meat). Deaths from laryngeal chondritis were observed in both sexes, but males had a higher incidence, particularly early in life. Cases were reported throughout the year, with examples observed in all months of the year, although there was a pattern of seasonal variation associated with age/sex of affected animals. Generally males tended to be affected throughout the year, with little variation in numbers on a month-to-month basis, whilst females were more likely to be affected either later in the year around the time coinciding with puberty (in the case of ewe lambs) or in the second quarter of the year, shortly after weaning (in the case of adult ewes). Animals with laryngeal chondritis had a heavier ultrasound scanning weight at around 20 weeks, although the weight of animals at other times had no effect. It was also noted that the depth of muscle and fat depth at 20 weeks had no effect on susceptibility. Maternal and/or nursing effects were observed. Ewes with affected lambs had a statistically higher mean pre-tupping body condition score than the others ewes in the flock, meaning that there may be some form of epigenetic role played in predisposing an animal to developing the condition later in life. The number of littermates had no effect, with no significant difference between those born as singletons, twins or triplets. However the rearing status of animals did have an effect, with animals reared as singletons having a higher incidence rate than those reared as pairs
Options for informal environmental management : the agricultural industry highlighted
The original article can be found at: http://www3.interscience.wiley.com Copyright John Wiley & Sons, Ltd and ERP Environment.Discussions are frequently found in the environmental press regarding the possible advantages to an organisation should they implement a formal environmental management system such as BS 7750, ISO 14001 and the EC Eco-Management and Audit Scheme (EMAS). It is also widely recognised that these formal systems, although theoretically applicable to all, are often seen by many organisations as being too unwieldy, too prescriptive, frequently too expensive and often too public. However, there are many alternative options available to organisations who do not wish to commit themselves to a formal accredited system. This paper discusses the various options currently in use for informal environmental management in agriculture with particular reference to a computerised system being developed at the University of Hertfordshire. Application examples are taken from the agricultural industry.Peer reviewe
Recommended from our members
Microscopic Examination of a Corrosion Front in Spent Nuclear Fuel
Spent uranium oxide nuclear fuel hosts a variety of trace chemical constituents, many of which must be sequestered from the biosphere during fuel storage and disposal. In this paper we present synchrotron x-ray absorption spectroscopy and microscopy findings that illuminate the resultant local chemistry of neptunium and plutonium within spent uranium oxide nuclear fuel before and after corrosive alteration in an air-saturated aqueous environment. We find the plutonium and neptunium in unaltered spent fuel to have a +4 oxidation state and an environment consistent with solid-solution in the UO{sub 2} matrix. During corrosion in an air-saturated aqueous environment, the uranium matrix is converted to uranyl U(VI)O{sub 2}{sup 2+} mineral assemblage that is depleted in plutonium and neptunium relative to the parent fuel. At the corrosion front interface between intact fuel and the uranyl-mineral corrosion layer, we find evidence of a thin ({approx}20 micrometer) layer that is enriched in plutonium and neptunium within a predominantly U{sup 4+} environment. Available data for the standard reduction potentials for NpO{sup 2+}/Np{sup 4+} and UO{sub 2}{sup 2+}/U{sup 4+} couples indicate that Np(IV) may not be effectively oxidized to Np(V) at the corrosion potentials of uranium dioxide spent nuclear fuel in air-saturated aqueous solutions. Neptunium is an important radionuclide in dose contribution according to performance assessment models of the proposed U. S. repository at Yucca Mountain, Nevada. A scientific understanding of how the UO{sub 2} matrix of spent nuclear fuel impacts the oxidative dissolution and reductive precipitation of neptunium is needed to predict its behavior at the fuel surface during aqueous corrosion. Neptunium would most likely be transported as aqueous Np(V) species, but for this to occur it must first be oxidized from the Np(IV) state found within the parent spent nuclear fuel [1]. In the immediate vicinity of the spent fuel's surface the redox and nucleation behavior is likely to promote/enhance nucleation of NpO{sub 2} and Np{sub 2}O{sub 5}. Alternatively, Np may be incorporated into uranyl (UO{sub 2}{sup 2+}) alteration phases [2]. In some cases, less-soluble elements such as plutonium will be enriched near the surface of the corroding fuel [3]. We have used focused synchrotron x-rays from the MRCAT beam line at the Advanced Photon Source (APS) at Argonne National Lab to examine a specimen of spent nuclear fuel that had been subject to 10 years of corrosion testing in an environment of humid air and dripping groundwater at 90 C [4]. We find evidence of a region, approximately 20 microns in thickness, enriched in plutonium and neptunium at the corrosion front that exists between the uranyl silicate alteration mineral rind and the unaltered uranium oxide fuel (Figures 1 and 2). The uranyl silicate is itself found to be depleted in these transuranic elements relative to their abundance relative to uranium in the parent fuel. This suggests a low mobility of these components owing to a resistance to oxidize further in the presence of a UO{sub 2}{sup 2+}/U{sup 4+} couple [5]
Competition of nuclear factor-erythroid 2 factors related transcription factor isoforms, Nrf1 and Nrf2, in antioxidant enzyme induction
AbstractAlthough the Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2) regulated expression of multiple antioxidant and cytoprotective genes through the electrophile responsive element (EpRE) is well established, interaction of Nrf2/EpRE with Nrf1, a closely-related transcription factor, is less well understood. Due to either proteolysis or alternative translation, Nrf1 has been found as proteins of varying size, p120, p95, and p65, which have been described as either activators of EpRE or competitive inhibitors of Nrf2. We investigated the effect of Nrf1 on EpRE-regulated gene expression using the catalytic and modifier subunits of glutamate cysteine ligase (GCLC and GCLM) as models and explored the potential role of Nrf1 in altering their expression in aging and upon chronic exposure to airborne nano-sized particulate matter (nPM). Nrf1 knockout resulted in the increased expression of GCLC and GCLM in human bronchial epithelial (HBE1) cells. Overexpression Nrf2 in combination with either p120 or p65 diminished or failed to further increase the GCLC- and GLCM-EpRE luciferase activity. All known forms of Nrf1 protein, remained unchanged in the lungs of mice with age or in response to nPM. Our study shows that Nrf1 could inhibit EpRE activity in vitro, whereas the precise role of Nrf1 in vivo requires further investigations. We conclude that Nrf1 may not be directly responsible for the loss of Nrf2-dependent inducibility of antioxidant and cytoprotective genes observed in aged animals
Running into New Territory in SUSY Parameter Space
The LEP-II bound on the light Higgs mass rules out the vast majority of
parameter space left to the Minimal Supersymmetric Standard Model (MSSM) with
weak-scale soft-masses. This suggests the importance of exploring extensions of
the MSSM with non-minimal Higgs physics. In this article, we explore a theory
with an additional singlet superfield and an extended gauge sector. The theory
has a number of novel features compared to both the MSSM and Next-to-MSSM,
including easily realizing a light CP-even Higgs mass consistent with LEP-II
limits, tan(beta) < 1, and a lightest Higgs which is charged. These features
are achieved while remaining consistent with perturbative unification and
without large stop-masses. Discovery modes at the Tevatron and LHC are
discussed.Comment: 15 pages, 5 figures; Typo in equation (4.5) corrected; submitted to
JHE
Comparison of deep inelastic electron-photon scattering data with the HERWIG and PHOJET Monte Carlo models
Deep inelastic electron-photon scattering is studied in the range from 1.2 to 30 GeV using the LEP1 data taken with the ALEPH, L3 and OPAL detectors at centre-of-mass energies close to the mass of the Z boson. Distributions of the measured hadronic final state are corrected to the hadron level and compared to the predictions of the HERWIG and PHOJET Monte Carlo models. For large regions in most of the distributions studied the results of the different experiments agree with one another. However, significant differences are found between the data and the models. Therefore the combined LEP data serve as an important input to improve on the Monte Carlo models.Deep inelastic electron-photon scattering is studied in the Q**2 range from 1.2 to 30 GeV**2 using the LEP1 data taken with the ALEPH, L3 and OPAL detectors at centre-of-mass energies close to the mass of the Z boson. Distributions of the measured hadronic final state are corrected to the hadron level and compared to the predictions of the HERWIG and PHOJET Monte Carlo models. For large regions in most of the distributions studied the results of the different experiments agree with one another. However, significant differences are found between the data and the models. Therefore the combined LEP data serve as an important input to improve on the Monte Carlo models
Search for the glueball candidates f0(1500) and fJ(1710) in gamma gamma collisions
Data taken with the ALEPH detector at LEP1 have been used to search for gamma
gamma production of the glueball candidates f0(1500) and fJ(1710) via their
decay to pi+pi-. No signal is observed and upper limits to the product of gamma
gamma width and pi+pi- branching ratio of the f0(1500) and the fJ(1710) have
been measured to be Gamma_(gamma gamma -> f0(1500)). BR(f0(1500)->pi+pi-) <
0.31 keV and Gamma_(gamma gamma -> fJ(1710)). BR(fJ(1710)->pi+pi-) < 0.55 keV
at 95% confidence level.Comment: 10 pages, 3 figure
Single Spin Asymmetry in Polarized Proton-Proton Elastic Scattering at GeV
We report a high precision measurement of the transverse single spin
asymmetry at the center of mass energy GeV in elastic
proton-proton scattering by the STAR experiment at RHIC. The was measured
in the four-momentum transfer squared range \GeVcSq, the region of a significant interference between the
electromagnetic and hadronic scattering amplitudes. The measured values of
and its -dependence are consistent with a vanishing hadronic spin-flip
amplitude, thus providing strong constraints on the ratio of the single
spin-flip to the non-flip amplitudes. Since the hadronic amplitude is dominated
by the Pomeron amplitude at this , we conclude that this measurement
addresses the question about the presence of a hadronic spin flip due to the
Pomeron exchange in polarized proton-proton elastic scattering.Comment: 12 pages, 6 figure
Longitudinal double-spin asymmetry and cross section for inclusive neutral pion production at midrapidity in polarized proton collisions at sqrt(s) = 200 GeV
We report a measurement of the longitudinal double-spin asymmetry A_LL and
the differential cross section for inclusive Pi0 production at midrapidity in
polarized proton collisions at sqrt(s) = 200 GeV. The cross section was
measured over a transverse momentum range of 1 < p_T < 17 GeV/c and found to be
in good agreement with a next-to-leading order perturbative QCD calculation.
The longitudinal double-spin asymmetry was measured in the range of 3.7 < p_T <
11 GeV/c and excludes a maximal positive gluon polarization in the proton. The
mean transverse momentum fraction of Pi0's in their parent jets was found to be
around 0.7 for electromagnetically triggered events.Comment: 6 pages, 3 figures, submitted to Phys. Rev. D (RC
- …