432 research outputs found
Gradients in abundance and diversity of ground-dwelling arthropods in temperate silvoarable fields
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Temperate agroforestry: yield of five key arable crops near tree rows of Populus X Canadensis
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Inoculation effects of two South African cyanobacteria strains on aggregate stability of a silt loam soil
Two South African cyanobacteria strains (coded 3g and 7e) of the genus Nostoc were evaluated for improvement of the aggregate stability of a silty loam soil with low organic C content and compared with Nostoc strain 9v isolated from a Tanzanian soil. The soil was either cropped with maize or non-cropped and inoculated with the three strains in a glasshouse. After 42 days, the aggregate stability based on mean weight diameter (MWD) and fragment size distribution were determined by fast wetting, wet stirring and slow wetting methods. Inoculation of the soil with strains 3g and 7e improved the soilâs MWD and increased its proportion of large aggregates, particularly in the cropped soil. The opposite was the case for aggregates in soils inoculated with the reference strain 9v. Strain 3g resulted in greater improvement of MWD estimated by fast wetting, while strains 7e and 9v improved aggregate stability estimated by wet stirring. Improvement of aggregate stability was more related to exocellular polysaccharide (EPS) content than organic C. The results suggest that indigenous strains with high potential for EPS production could improve the soil structural stability of degraded soils in South Africa.Key words: Aggregate stability, exocellular polysaccharides, indigenous cyanobacteria, mean weight diameter
Evidence of a high incidence of subclinically affected calves in a herd of cattle with fatal cases of Bovine Neonatal Pancytopenia (BNP).
BACKGROUND: Bovine Neonatal Pancytopenia (BNP) is a disease of calves characterised by bone marrow trilineage hypoplasia, mediated by ingestion of alloantibodies in colostrum. Suspected subclinical forms of BNP have been reported, suggesting that observed clinical cases may not represent the full extent of the disease. However to date there are no objective data available on the incidence of subclinical disease or its temporal distribution. This study aimed to 1) ascertain whether subclinical BNP occurs and, if so, to determine the incidence on an affected farm and 2) determine whether there is evidence of temporal clustering of BNP cases on this farm. To achieve these aims, haematological screening of calves born on the farm during one calving season was carried out, utilising blood samples collected at defined ages. These data were then analysed in comparison to data from both known BNP-free control animals and histopathologically confirmed BNP cases. An ordinal logistic regression model was used to create a composite haematology score to predict the probabilities of calves being normal, based on their haematology measurements at 10â14 days old. RESULTS: This study revealed that 15% (21 of 139) of the clinically normal calves on this farm had profoundly abnormal haematology (<5% chance of being normal) and could be defined as affected by subclinical BNP. Together with clinical BNP cases, this gave the study farm a BNP incidence of 18%. Calves with BNP were found to be distributed throughout the calving period, with no clustering, and no significant differences in the date of birth of cases or subclinical cases were found compared to the rest of the calves. This study did not find any evidence of increased mortality or increased time from birth to sale in subclinical BNP calves but, as the study only involved a single farm and adverse effects may be determined by other inter-current diseases it remains possible that subclinical BNP has a detrimental impact on the health and productivity of calves under certain circumstances. CONCLUSIONS: Subclinical BNP was found to occur at a high incidence in a herd of cattle with fatal cases of BNP
Crystal structure of the proteasomal deubiquitylation module Rpn8-Rpn11
The ATP-dependent degradation of polyubiquitylated proteins by the 26S proteasome is essential for the maintenance of proteome stability and the regulation of a plethora of cellular processes. Degradation of substrates is preceded by the removal of polyubiquitin moieties through the isopeptidase activity of the subunit Rpn11. Here we describe three crystal structures of the heterodimer of the Mpr1-Pad1-N-terminal domains of Rpn8 and Rpn11, crystallized as a fusion protein in complex with a nanobody. This fusion protein exhibits modest deubiquitylation activity toward a model substrate. Full activation requires incorporation of Rpn11 into the 26S proteasome and is dependent on ATP hydrolysis, suggesting that substrate processing and polyubiquitin removal are coupled. Based on our structures, we propose that premature activation is prevented by the combined effects of low intrinsic ubiquitin affinity, an insertion segment acting as a physical barrier across the substrate access channel, and a conformationally unstable catalytic loop in Rpn11. The docking of the structure into the proteasome EM density revealed contacts of Rpn11 with ATPase subunits, which likely stabilize the active conformation and boost the affinity for the proximal ubiquitin moiety. The narrow space around the Rpn11 active site at the entrance to the ATPase ring pore is likely to prevent erroneous deubiquitylation of folded proteins
Herd-level animal management factors associated with the occurrence of bovine neonatal pancytopenia in calves in a multicountry study
Since 2007, mortality associated with a previously unreported haemorrhagic disease has been observed in young calves in several European countries. The syndrome, which has been named âbovine neonatal pancytopeniaâ (BNP), is characterised by thrombocytopenia, leukocytopenia and a panmyelophthisis. A herd-level case-control study was conducted in four BNP affected countries (Belgium, France, Germany and the Netherlands) to identify herd management risk factors for BNP occurrence. Data were collected using structured face-to-face and telephone interviews of farm managers and their local veterinarians. In total, 363 case farms and 887 control farms were included in a matched multivariable conditional logistic regression analysis. Case-control status was strongly associated with the odds of herd level use of the vaccine PregSureÂź BVD (PregSure, Pfizer Animal Health) (matched adjusted odds ratio (OR) 107.2; 95% CI: 41.0â280.1). This was also the case for the practices of feeding calves colostrum from the calfâs own dam (OR 2.0; 95% CI: 1.1â3.4) or feeding pooled colostrum (OR 4.1; 95% CI: 1.9â8.8). Given that the study had relatively high statistical power and represented a variety of cattle production and husbandry systems, it can be concluded with some confidence that no other herd level management factors are competent causes for a sufficient cause of BNP occurrence on herd level. It is suggested that genetic characteristics of the dams and BNP calves should be the focus of further investigations aimed at identifying the currently missing component causes that together with PregSure vaccination and colostrum feeding represent a sufficient cause for occurrence of BNP in calves
Climate Change is an Emerging Threat to Perinatal Mental Health
Objective:
In this discussion, we build the case for why climate change is an emerging threat to perinatal mental health.
Method:
A search of current literature on perinatal and maternal mental health and extreme weather events was conducted in PubMed/MEDLINE and Web of Science databases. Only articles focusing on maternal mental health were included in this narrative review.
Results:
The perinatal period represents a potentially challenging timeframe for women for several reasons. Necessary role adjustments (reprioritization), changes in oneâs ability to access pre-birth levels (and types) of social support, fluctuating hormones, changes in body shape, and possible complications during pregnancy, childbirth, or postpartum are just a few of the factors that can impact perinatal mental health. Trauma is also a risk factor for negative mood symptoms and can be experienced as the result of many different types of events, including exposure to extreme weather/natural disasters.
Conclusion:
While the concepts of âeco-anxiety,â âclimate despair,â and âclimate anxietyâ have garnered attention in the mainstream media, there is little to no discussion of how the climate crisis impacts maternal mental health. This is an important omission as the motherâs mental health impacts the family unit as a whole
Electrons in High-Tc Compounds: Ab-Initio Correlation Results
Electronic correlations in the ground state of an idealized infinite-layer
high-Tc compound are computed using the ab-initio method of local ansatz.
Comparisons are made with the local-density approximation (LDA) results, and
the correlation functions are analyzed in detail. These correlation functions
are used to determine the effective atomic-interaction parameters for model
Hamiltonians. On the resulting model, doping dependencies of the relevant
correlations are investigated. Aside from the expected strong atomic
correlations, particular spin correlations arise. The dominating contribution
is a strong nearest neighbor correlation that is Stoner-enhanced due to the
closeness of the ground state to the magnetic phase. This feature depends
moderately on doping, and is absent in a single-band Hubbard model. Our
calculated spin correlation function is in good qualitative agreement with that
determined from the neutron scattering experiments for a metal.Comment: 21pp, 5fig, Phys. Rev. B (Oct. 98
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