15,823 research outputs found
Pulse of inflammatory proteins in the pregnant uterus of European polecats (Mustela putorius) leading to the time of implantation
Uterine secretory proteins protect the uterus and conceptuses against infection, facilitate implantation, control cellular damage resulting from implantation, and supply pre-implantation embryos with nutrients. Unlike in humans, the early conceptus of the European polecat (Mustela putorius; ferret) grows and develops free in the uterus until implanting at about 12 days after mating. We found that the proteins appearing in polecat uteri changed dramatically with time leading to implantation. Several of these proteins have also been found in pregnant uteri of other eutherian mammals. However, we found a combination of two increasingly abundant proteins that have not been recorded before in pre-placentation uteri. First, the broad-spectrum proteinase inhibitor α2-macroglobulin rose to dominate the protein profile by the time of implantation. Its functions may be to limit damage caused by the release of proteinases during implantation or infection, and to control other processes around sites of implantation. Second, lipocalin-1 (also known as tear lipocalin) also increased substantially in concentration. This protein has not previously been recorded as a uterine secretion in pregnancy in any species. If polecat lipocalin-1 has similar biological properties to that of humans, then it may have a combined function in antimicrobial protection and transporting or scavenging lipids. The changes in the uterine secretory protein repertoire of European polecats is therefore unusual, and may be representative of pre-placentation supportive uterine secretions in mustelids (otters, weasels, badgers, mink, wolverines) in general
Increasing resilience of ATM networks using traffic monitoring and automated anomaly analysis
Systematic network monitoring can be the cornerstone for
the dependable operation of safety-critical distributed
systems. In this paper, we present our vision for informed
anomaly detection through network monitoring and
resilience measurements to increase the operators'
visibility of ATM communication networks. We raise the
question of how to determine the optimal level of
automation in this safety-critical context, and we present a
novel passive network monitoring system that can reveal
network utilisation trends and traffic patterns in diverse
timescales. Using network measurements, we derive
resilience metrics and visualisations to enhance the
operators' knowledge of the network and traffic behaviour,
and allow for network planning and provisioning based on
informed what-if analysis
Consumer Perception of Sorghum Variety Attributes in the Lake Zone Tanzania
Many sorghum varieties have been developed by research institutes in an effort to address food security problems in the semi-arid areas of Tanzania. Although sorghum is better adapted to drier areas than maize, farmer adoption rates for sorghum varieties are always lower than that of maize. In addition, maize based food is more acceptable to urban consumers than sorghum based food. In this study consumer evaluated quality attributes of sorghum ugali based on different varieties in order to determine marketing potential relating to the different improved sorghum varieties. A total of 231 consumers, randomly selected from urban and rural areas participated in a food panel to evaluate ugali prepared from five sorghum varieties (three improved, two local). Conjoint analysis was used to determine consumer perceptions of the variety attributes, while a logistic model was applied to determine preference ranking of different varieties. The results indicated that the color and taste of sorghum ugali were the most important criteria used by consumers to evaluate the quality ugali. The study results indicated that sorghum ugali with white/khaki color and the majority of panel participants preferred neutral or slightly sweet taste. Consumers from rural and urban areas accepted two improved varieties; only consumers from rural areas accepted the remaining variety.Adoption, consumer perception, conjoint analysis, sorghum varieties, Tanzania, Agricultural and Food Policy, Consumer/Household Economics, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Marketing, Productivity Analysis, Research and Development/Tech Change/Emerging Technologies,
Diversity in parasitic nematode genomes: the microRNAs of Brugia pahangi and Haemonchus contortus are largely novel
<b>BACKGROUND:</b>
MicroRNAs (miRNAs) play key roles in regulating post-transcriptional gene expression and are essential for development in the free-living nematode Caenorhabditis elegans and in higher organisms. Whether microRNAs are involved in regulating developmental programs of parasitic nematodes is currently unknown. Here we describe the the miRNA repertoire of two important parasitic nematodes as an essential first step in addressing this question.
<b>RESULTS:</b>
The small RNAs from larval and adult stages of two parasitic species, Brugia pahangi and Haemonchus contortus, were identified using deep-sequencing and bioinformatic approaches. Comparative analysis to known miRNA sequences reveals that the majority of these miRNAs are novel. Some novel miRNAs are abundantly expressed and display developmental regulation, suggesting important functional roles. Despite the lack of conservation in the miRNA repertoire, genomic positioning of certain miRNAs within or close to specific coding genes is remarkably conserved across diverse species, indicating selection for these associations. Endogenous small-interfering RNAs and Piwi-interacting (pi)RNAs, which regulate gene and transposon expression, were also identified. piRNAs are expressed in adult stage H. contortus, supporting a conserved role in germline maintenance in some parasitic nematodes.
<b>CONCLUSIONS:</b>
This in-depth comparative analysis of nematode miRNAs reveals the high level of divergence across species and identifies novel sequences potentially involved in development. Expression of novel miRNAs may reflect adaptations to different environments and lifestyles. Our findings provide a detailed foundation for further study of the evolution and function of miRNAs within nematodes and for identifying potential targets for intervention
Effects of single and mixed infections with wild type and genetically modified Helicoverpa armigera nucleopolyhedrovirus on movement behaviour of cotton bollworm larvae
Naturally occurring insect viruses can modify the behaviour of infected insects and thereby modulate virus transmission. Modifications of the virus genome could alter these behavioural effects. We studied the distance moved and the position of virus-killed cadavers of fourth instars of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) infected with a wild-type genotype of H. armigera nucleopolyhedrovirus (HaSNPV) or with one of two recombinant genotypes of this virus on cotton plants. The behavioural effects of virus infection were examined both in larvae infected with a single virus genotype, and in larvae challenged with mixtures of the wild-type and one of the recombinant viruses. An egt-negative virus variant caused more rapid death and lower virus yield in fourth instars, but egt-deletion did not produce consistent behavioural effects over three experiments, two under controlled glasshouse conditions and one in field cages. A recombinant virus containing the AaIT-(Androctonus australis Hector) insect-selective toxin gene, which expresses a neurotoxin derived from a scorpion, caused faster death and cadavers were found lower down the plant than insects infected with unmodified virus. Larvae that died from mixed infections of the AaIT-expressing recombinant and the wild-type virus died at positions significantly lower, compared to infection with the pure wild-type viral strain. The results indicate that transmission of egt-negative variants of HaSNPV are likely to be affected by lower virus yield, but not by behavioural effects of egt gene deletion. By contrast, the AaIT recombinant will produce lower virus yields as well as modified behaviour, which together can contribute to reduced virus transmission under field conditions. In addition, larvae infected with both the wild-type virus and the toxin recombinant behaved as larvae infected with the toxin recombinant only, which might be a positive factor for the risk assessment of such toxin recombinants in the environment
Categorisation of dairy production systems: A strategy for targeting meaningful development of the systems in Uganda
Dairy production is a major contributor towards national economies and household food security and incomes in sub-Saharan Africa (SSA). Milk production in the region is estimated at 1.27 million metric tonnes year-1. However, this level of milk production is inadequate for the existing human population who would require 103 million metric tonnes year-1. In Uganda, milk production only meets approximately 20% of the population's nutritional requirements. As such, methods need to be sought to increase milk production in the region.
Research efforts have made strides in identifying the causes of the production-demand gap in the SSA region and a spectrum of interventions to bolster the productivity. Unfortunately, these efforts have by far yielded insignificant results. First and foremost, for exploiting the full potential of the dairy cattle population in the region, among the critical elements often overlooked in research and development processes is the recognition of systematic parametric variations within the sector, which if considered could provide entry-points for targeting intervention efforts. One such high potential entry-point is the recognition of the existence of a dairy intensification "vector" across a country or region, along which exist sections with sequentially marked nuclei of fairly uniform socio-economic and biophysical dairy sub-systems features. To enhance the process of targeting research and development in the Ugandan dairy sector, dairy production systems in the country were categorised on basis of level of intensification of production.
Data were collected from 300 households in Mbarara, Masaka and Jinja districts in Uganda. The major variables derived from the data for the categorisation process were those related with milk production, expenditure, income, land area and cattle herds. The data was subjected to a cluster analysis which although produced 16 groups only five had prominent membership (above 5% of the farms). The five major clusters were selected as representative of the dairy production systems. A ranking system was used to develop an intensification continuum for the 5 systems. Herding-on own and communal land (cluster 9) was the least intensive, this was followed by Herding-mainly on own land (cluster 12) and Fenced (cluster 8) respectively. Semi-Zero Grazing (cluster 15) and Zero Grazing (cluster 13) were the most intensive dairy production systems with the latter being at the highest end of the continuum
Orthogonal polynomials with asymptotically periodic recurrence coefficients
AbstractGiven the coefficients in the three term recurrence relation satisfied by orthogonal polynomials, we investigate the properties of those classes of polynomials whose coefficients are asymptotically periodic. Assuming a rate of convergence of the coefficients to their asymptotic values, we construct the measure with respect to which the polynomials are orthogonal and discuss their asymptotic behavior
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Interhemispheric coupling, the West Antarctic Ice Sheet and warm Antarctic interglacials
Ice core evidence indicates that even though atmospheric
CO2 concentrations did not exceed 300 ppm at
any point during the last 800 000 years, East Antarctica was
at least 3–4 C warmer than preindustrial (CO2 280 ppm) in each of the last four interglacials. During the previous three interglacials, this anomalous warming was short lived (3000 years) and apparently occurred before the completion of Northern Hemisphere deglaciation. Hereafter, we refer to these periods as “Warmer than Present Transients” (WPTs). We present a series of experiments to investigate the impact of deglacial meltwater on the Atlantic Meridional Overturning Circulation (AMOC) and Antarctic temperature.
It is well known that a slowed AMOC would increase southern
sea surface temperature (SST) through the bipolar seesaw
and observational data suggests that the AMOC remained
weak throughout the terminations precedingWPTs, strengthening rapidly at a time which coincides closely with peak Antarctic temperature. We present two 800 kyr transient simulations using the Intermediate Complexity model GENIE-1 which demonstrate that meltwater forcing generates transient southern warming that is consistent with the timing of WPTs, but is not sufficient (in this single parameterisation) to reproduce the magnitude of observed warmth. In order to investigate model and boundary condition uncertainty, we present three ensembles of transient GENIE-1 simulations across Termination II (135 000 to 124 000 BP) and three snapshot HadCM3 simulations at 130 000 BP. Only with consideration of the possible feedback of West Antarctic Ice Sheet (WAIS)
retreat does it become possible to simulate the magnitude of
observed warming
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Inflammasomes: Molecular Regulation and Implications for Metabolic and Cognitive Diseases
Inflammasomes are specialized signaling platforms critical for the regulation of innate immune and inflammatory responses. Various NLR family members (i.e., NLRP1, NLRP3, and IPAF) as well as the PYHIN family member AIM2 can form inflammasome complexes. These multi-protein complexes activate inflammatory caspases (i.e., caspase-1) which in turn catalyze the maturation of select pro-inflammatory cytokines, including interleukin (IL)-1β and IL-18. Activation of the NLRP3 inflammasome typically requires two initiating signals. Toll-like receptor (TLR) and NOD-like receptor (NLR) agonists activate the transcription of pro-inflammatory cytokine genes through an NF-κB-dependent priming signal. Following exposure to extracellular ATP, stimulation of the P2X purinoreceptor-7 (P2X7R), which results in K+ efflux, is required as a second signal for NLRP3 inflammasome formation. Alternative models for NLRP3 activation involve lysosomal destabilization and phagocytic NADPH oxidase and/or mitochondria-dependent reactive oxygen species (ROS) production. In this review we examine regulatory mechanisms that activate the NLRP3 inflammasome pathway. Furthermore, we discuss the potential roles of NLRP3 in metabolic and cognitive diseases, including obesity, type 2 diabetes mellitus, Alzheimer’s disease, and major depressive disorder. Novel therapeutics involving inflammasome activation may result in possible clinical applications in the near future
Local Charge Excesses in Metallic Alloys: a Local Field Coherent Potential Approximation Theory
Electronic structure calculations performed on very large supercells have
shown that the local charge excesses in metallic alloys are related through
simple linear relations to the local electrostatic field resulting from
distribution of charges in the whole crystal.
By including local external fields in the single site Coherent Potential
Approximation theory, we develop a novel theoretical scheme in which the local
charge excesses for random alloys can be obtained as the responses to local
external fields. Our model maintains all the computational advantages of a
single site theory but allows for full charge relaxation at the impurity sites.
Through applications to CuPd and CuZn alloys, we find that, as a general rule,
non linear charge rearrangements occur at the impurity site as a consequence of
the complex phenomena related with the electronic screening of the external
potential. This nothwithstanding, we observe that linear relations hold between
charge excesses and external potentials, in quantitative agreement with the
mentioned supercell calculations, and well beyond the limits of linearity for
any other site property.Comment: 11 pages, 1 table, 7 figure
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