2,290 research outputs found
Wildlife-livestock interactions and risk areas for cross-species spread of bovine tuberculosis
The transmission of diseases between livestock and wildlife can be a hindrance to effective disease control. Maintenance hosts and contact rates should be explored to further understand the transmission dynamics at the wildlife-livestock interface. Bovine tuberculosis (BTB) has been shown to have wildlife maintenance hosts and has been confirmed as present in the African buffalo (Syncerus caffer) in the Queen Elizabeth National Park (QENP) in Uganda since the 1960s. The first aim of this study was to explore the spatio-temporal spread of cattle illegally grazing within the QENP recorded by the Uganda Wildlife Authority (UWA) rangers in a wildlife crime database. Secondly, we aimed to quantify wildlife-livestock interactions and cattle movements, on the border of QENP, using a longitudinal questionnaire completed by 30 livestock owners. From this database, 426 cattle sightings were recorded within QENP in 8 years. Thirteen (3.1%) of these came within a 300 m–4 week space-time window of a buffalo herd, using the recorded GPS data. Livestock owners reported an average of 1.04 (95% CI 0.97–1.11) sightings of Uganda kob, waterbuck, buffalo or warthog per day over a 3-month period, with a rate of 0.22 (95% CI 0.20–0.25) sightings of buffalo per farmer per day. Reports placed 85.3% of the ungulate sightings and 88.0% of the buffalo sightings as further than 50 m away. Ungulate sightings were more likely to be closer to cattle at the homestead (OR 2.0, 95% CI 1.1–3.6) compared with the grazing area. Each cattle herd mixed with an average of five other cattle herds at both the communal grazing and watering points on a daily basis. Although wildlife and cattle regularly shared grazing and watering areas, they seldom came into contact close enough for aerosol transmission. Between species infection transmission is therefore likely to be by indirect or non-respiratory routes, which is suspected to be an infrequent mechanism of transmission of BTB. Occasional cross-species spillover of infection is possible, and the interaction of multiple wildlife species needs further investigation. Controlling the interface between wildlife and cattle in a situation where eradication is not being considered may have little impact on BTB disease control in cattle
A cointegration model for search equilibrium wage formation
In flow models of the labor market, wages are determined by negotiations between workers and employers on the surplus value of a realized match. From this perspective, this paper presents an econometric analysis of the influence of labor market flows on wage formation as an alternative to the traditional specification of wage equations in which unemployment represents Phillips-curve or wage-curve effects. The paper estimates a dynamic wage equation for the Netherlands using a cointegration approach. It finds that labor flows, and notably flows from outside the labor market, are important determinants of both short-run and long-run wage setting.wage curve, labor market flows, cointegration model
A spatially resolved relaxation method for pLTE plasma diagnostics in free-burning arcs
We report on a relaxation method to determine the electron-to-gas temperature ratio in the near-cathode region of a low-current free-burning arc operated in argon under atmospheric pressure. We used an intensified CCD camera to record the relaxation process after a fast power-interruption of the discharge with a time resolution better than 1 µs. For the CCD images we applied an ABEL inversion procedure yielding 3D information about the temperature ratio ? := Te/Tg with a spatial resolution of 50 µm. We deduced spatially resolved values of ? from the relaxation experiment using independently measured values of Te and ne, so we could determine all free parameters in the partial LTE model
Interaction-induced chiral p_x \pm i p_y superfluid order of bosons in an optical lattice
The study of superconductivity with unconventional order is complicated in
condensed matter systems by their extensive complexity. Optical lattices with
their exceptional precision and control allow one to emulate superfluidity
avoiding many of the complications of condensed matter. A promising approach to
realize unconventional superfluid order is to employ orbital degrees of freedom
in higher Bloch bands. In recent work, indications were found that bosons
condensed in the second band of an optical chequerboard lattice might exhibit
p_x \pm i p_y order. Here we present experiments, which provide strong evidence
for the emergence of p_x \pm i p_y order driven by the interaction in the local
p-orbitals. We compare our observations with a multi-band Hubbard model and
find excellent quantitative agreement
Exchange parameters from approximate self-interaction correction scheme
The approximate atomic self-interaction corrections (ASIC) method to density
functional theory is put to the test by calculating the exchange interaction
for a number of prototypical materials, critical to local exchange and
correlation functionals. ASIC total energy calculations are mapped onto an
Heisenberg pair-wise interaction and the exchange constants J are compared to
those obtained with other methods. In general the ASIC scheme drastically
improves the bandstructure, which for almost all the cases investigated
resemble closely available photo-emission data. In contrast the results for the
exchange parameters are less satisfactory. Although ASIC performs reasonably
well for systems where the magnetism originates from half-filled bands, it
suffers from similar problems than those of LDA for other situations. In
particular the exchange constants are still overestimated. This reflects a
subtle interplay between exchange and correlation energy, not captured by the
ASIC.Comment: 10 page
The role of Ar III in quantitative spectroscopy on hot argon plasmas
We perform quantitative optical emission spectroscopy on the hot core of the cathode region of a free-burning arc in argon under atmospheric pressure. As the peak temperatures in the centre of the discharge exceed 22 000 K we are able to observe three spectra of argon (Ar I, Ar II and Ar III) and the continuum emission. We report on some inconsistencies concerning the evaluation of Ar III radiation in both line and continuum emission. These are caused by erroneous data in the literature and common misconceptions about the influence of Ar III on the plasma emission. We discuss the impact of this fact on published data
Did Neoliberalizing West African Forests Produce a New Niche for Ebola?
A recent study introduced a vaccine that controls Ebola Makona, the Zaire ebolavirus variant that has infected 28,000 people in West Africa. We propose that even such successful advances are insufficient for many emergent diseases. We review work hypothesizing that Makona, phenotypically similar to much smaller outbreaks, emerged out of shifts in land use brought about by neoliberal economics. The epidemiological consequences demand a new science that explicitly addresses the foundational processes underlying multispecies health, including the deep-time histories, cultural infrastructure, and global economic geographies driving disease emergence. The approach, for instance, reverses the standard public health practice of segregating emergency responses and the structural context from which outbreaks originate. In Ebola's case, regional neoliberalism may affix the stochastic "friction" of ecological relationships imposed by the forest across populations, which, when above a threshold, keeps the virus from lining up transmission above replacement. Export-led logging, mining, and intensive agriculture may depress such functional noise, permitting novel spillovers larger forces of infection. Mature outbreaks, meanwhile, can continue to circulate even in the face of efficient vaccines. More research on these integral explanations is required, but the narrow albeit welcome success of the vaccine may be used to limit support of such a program.SCOPUS: re.jinfo:eu-repo/semantics/publishe
Task analysis: the missing link in software development methodologies
Systems development methods or software methodologies have evolved
considerably over the past few years. This development has tended to fall into two main areas: Software Engineering and Human Computer Interaction (HCI). The two main techniques proposed in Software Engineering were Structured Analysis, as proposed by Ross and DeMarco; and Semantic Modelling. These two different approaches were later combined to yield Modern Structured Analysis, in which Structured Analysis was augmented with data modelling techniques.
Modern Structured Analysis was subsequently replaced by Object Oriented Analysis and Design (OOAD) which adopted a holistic approach to data and processes, encapsulating them into objects.
In the HCI domain, design methods such as Hierarchical Task Analysis (HTA) and Task Analysis for Knowledge Descriptions (TAKD), have long been used to model the cognitive nature of the tasks performed by the users. Recent work by Walsh, Um, Long and Sutcliffe have proposed combining Task Analysis (TA) with Structured Analysis and Design methods, in order to improve system usability. Analysis for Task Object Modelling (ATOM), as proposed by Walsh, is an example of such a method which combines TA with object modelling in an integrated life cycle approach.
This article will review the major Software Engineering methods, together with the principal HCI methods and motivate for the integration of the two areas on the basis of improved system usability. A taxonomy of software development methods as proposed by Blum will be reviewed and a proposal made to augment the framework to include the issue of user-centered design methods. The extended framework will then be used to classify several of the principal software design methodologies, together with the principal HCI methods. Each of these methodologies will be reviewed and conclusions drawn as to the efficacy of each in the context of the software life cycle. We will demonstrate that all of the traditional design methodologies fail to include Task Analysis (TA). An alternative methodology, Analysis for Task Object Modelling, as proposed by Walsh, will be discussed, which includes TA with object modelling. We will motivate that TA is an essential
part of Requirements Analysis and HCI design. Furthermore, failure to include TA may result in serious usability problems. Methods like ATOM, which combine TA with OOAD, are thus the most applicable software methodologies for designing usable systems in the future. Further research, however, is needed to improve and integrate the conceptual modelling techniques in ATOM
Low molecular weight heparin-induced skin necrosis—a systematic review
Background: Low molecular weight heparins (LMWHs) are currently used as a standard for anti-thrombotic therapy. Skin necrosis caused by LMWH is a rare and probably under-reported complication. The aim of our systematic review is to analyse the present literature for cases of LMWH-induced skin necrosis, emphasising the pathogenesis, clinical pattern, and management of this rare side effect. Methods: We performed a Medline literature search (PubMed database) and manual cross-referencing to identify all articles related to LMWH-induced skin necrosis. Data were analysed for type of LMWH used, time until skin necrosis occurred, localisation, size, laboratory findings, switch anticoagulant, complications, and outcome. Additionally, the case of a patient from our hospital is presented. Results: We included a total of 20 articles (21 cases) reporting on LMWH-induced skin necrosis. Skin necrosis occurred locally and distant from the injection site. Heparin-induced antibodies were frequently observed (positive 9/11 articles, negative 2/11). However, severe thrombocytopenia (platelet count <100,000cells/ml) occurred in only four cases, while platelet count remained normal in 50% of the cases. After patients had been switched to other anti-thrombotic drugs, the clinical course was usually benign; however, reconstructive surgery was necessary in two cases. Conclusion: LMWH-induced skin necrosis may occur as part of the heparin-induced thrombocytopenia (HIT) syndrome, but other pathomechanisms, including allergic reactions and local trauma, may also be involved. When HIT is excluded, unfractionated heparin is a safe switch anticoagulant. Otherwise, non-heparin preparations such as hirudin or fondaparinux should be preferre
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