616 research outputs found
Intense human-animal interaction and limited capacity for the surveillance of zoonoses as drivers for Hepatitis E virus infections among animals and humans in Lao PDR
Purpose: In Lao People's Democratic Republic (PDR), overlapping habitats of the population and livestock create a propitious environment for zoonoses. Insufficient hygienic measures in slaughterhouses and in rural settings further increase the risk for zoonotic transmission. Limited laboratory capacity as well as lack of background knowledge prevent timely control of disease oubreaks. Here, we assess the occurrence and transmission of Hepatits E virus (HEV), as well as public awareness of zoonoses.
Methods & Materials: In 2015 and 2016, samples were collected from ruminants in rural areas (n=211), as well as from slaughterhouse workers (n=129) and slaughter pigs (n=290) in Lao PDR. Using commercial ELISAs, presence of antibodies (IgG, IgM and IgA) against HEV was assessed. Fecal shedding of HEV by animals was investigated using a generic real-time PCR. Detected viruses were characterized by Sanger sequencing if feasible. Using a standardized questionnaire, data on risk factors for zoonotic pathogen transmission and awareness on zoonoses were captured. Much emphasis was placed on collaborating with local actors and on strengthening laboratory capacities.
Results: Anti-HEV antibodies were detected in 13% of ruminants in rural settings and in 46% of slaughter pigs. 7% of the ruminants and 2% of the pigs shed HEV that were thus far not characterizable. While anti-HEV antibody seroprevalence was of 33% in people exposed to pigs, only 15% of the non-exposed control group were seropositive (p= 0.001). Awareness of zoonoses among farmers and slaughterhouse workers was low. Wearing protective equipment was associated with a decrease in anti-HEV antibody detection (p=0.024). Limiting the consumption and use of groundwater and cooking of meat further reduced the risk for HEV infection in a domestic context.
Conclusion: We could show that people who are exposed to livestock and pigs are at higher risk for contracting HEV than the general population. Although shedding rates were relatively low, animals may represent an infection source that can be controlled by applying personal protective equipment. Building the capacity for the detection and prevention of infectious diseases and increasing awareness about zoonoses in developing countries is a prerequisite for combating infectious disease outbreaks in future
Livestock diseases threatening smallholder farmers in Lao people's Democratic Republic
Purpose: In Lao People's Democratic Republic, uncontrolled animal trade, lack of animal containment and limited access to veterinary services are a growing-ground for virus spread. Foot-and-Mouth Disease (FMD) and several avian viruses are enzootic and threaten subsistence farmers. We assessed the (sero-)prevalence of several livestock viruses, and evaluated the knowledge, attitude, and practice of smallholder farmers towards FMD.
Methods & Materials: In 2018, sera were collected from 394 domestic ruminants and screened using an ELISA that differentiates between infected and vaccinated animals. Questionnaires (n = 101) were statistically explored to identify knowledge gaps and risk factors related to FMD. In addition, oral and cloacal swabs, collected from 619 backyard poultry in 2011, 2014 and 2015, were tested by PCR for Newcastle disease (NDV), Influenza A, Coronavirus (CoV) and Chicken Anemia Virus (CAV). 206 poultry sera were screened by ELISA for the presence of anti-NDV and –Influenza A antibodies. Statistical and phylogenetic analyses revealed the viral infection patterns.
Results: Although most farmers had very limited knowledge about FMD, many could correctly enumerate the symptoms and observed outbreaks recently. This was confirmed by our laboratory analysis: overall 37.1% of the animals were seropositive and 72.3% of the farms had at least one seropositive animal. Approx. 90% of the farmers reported that FMD negatively affects livestock trade and health. Moreover, we found high positivity rates of CoV and CAV RNA in cloacal and oral swabs (CoV: 38.3% and 6.2%; CAV: 16.1% and 1.7%). Younger animals were more likely to shed both, CoV and CAV, and similar virus strains co-circulated in chickens and ducks. Despite serological evidence of NDV and influenza A circulation (86.9% and 1.9%), viral RNA was detected in none of the swabs.
Conclusion: A large proportion of the Lao population relies on subsistence livestock production which is, as shown here, severely compromised by the circulating viruses. To secure their livelihoods, vaccination programmes should target all susceptible hosts and achieve a high coverage throughout the country. These campaigns should be complemented by community-based sensitization to raise the awareness about prevention strategies, such as quarantine and trade restrictions
The application of linguistic processing to automatic abstract generation
One approach to the problem of generating abstracts by computer is to extract from a source text those sentences which give a strong indication of the central subject matter and findings of the paper. Not surprisingly, concatenations of extracted sentences show a lack of cohesion, due partly to the frequent occurrence of anaphoric references. This paper describes the text processing which was necessary to identify these anaphors so that they may be utilised in the enhancement of the sentence selection criteria. It is assumed that sentences which contain non-anaphoric nounphrases and introduce key concepts into the text are worthy of inclusion in an abstract. The results suggest that the key
concepts are indeed identified but the abstracts are too long. Further recommendations are made to continue this work in abstracting which makes use of text structure
The application of linguistic processing to automatic abstract generation
One approach to the problem of generating abstracts by computer is to extract from a source text those sentences which give a strong indication of the central subject matter and findings of the paper. Not surprisingly, concatenations of extracted sentences show a lack of cohesion, due partly to the frequent occurrence of anaphoric references. This paper describes the text processing which was necessary to identity these anaphors so that they may be utilised in the enhancement of the sentence selection criteria. It is assumed that sentences which contain non-anaphoric nounphrases and introduce key concepts into the text are worthy of inclusion in an abstract. The results suggest that the key concepts are indeed identified but the abstracts are too long. Further recommendations are made to continue this work in abstracting which makes use of text structure
The price of rapid exit in venture capital-backed IPOs
This paper proposes an explanation for two empirical puzzles surrounding initial public offerings (IPOs). Firstly, it is well documented that IPO underpricing increases during “hot issue” periods. Secondly, venture capital (VC) backed IPOs are less underpriced than non-venture capital backed IPOs during normal periods of activity, but the reverse is true during hot issue periods: VC backed IPOs are more underpriced than non-VC backed ones. This paper shows that when IPOs are driven by the initial investor’s desire to exit from an existing investment in order to finance a new venture, both the value of the new venture and the value of the existing firm to be sold in the IPO drive the investor’s choice of price and fraction of shares sold in the IPO. When this is the case, the availability of attractive new ventures increases equilibrium underpricing, which is what we observe during hot issue periods. Moreover, I show that underpricing is affected by the severity of the moral hazard problem between an investor and the firm’s manager. In the presence of a moral hazard problem the degree of equilibrium underpricing is more sensitive to changes in the value of the new venture. This can explain why venture capitalists, who often finance firms with more severe moral hazard problems, underprice IPOs less in normal periods, but underprice more strongly during hot issue periods. Further empirical implications relating the fraction of shares sold and the degree of underpricing are presented
Reversed anisotropies and thermal contraction of FCC (110) surfaces
The observed anisotropies of surface vibrations for unreconstructed FCC metal
(110) surfaces are often reversed from the "common sense" expectation. The
source of these reversals is investigated by performing ab initio density
functional theory calculations to obtain the surface force constant tensors for
Ag(110), Cu(110) and Al(110). The most striking result is a large enhancement
in the coupling between the first and third layers of the relaxed surface,
which strongly reduces the amplitude of out-of-plane vibrations of atoms in the
first layer. This also provides a simple explanation for the thermal
contraction of interlayer distances. Both the anisotropies and the thermal
contraction arise primarily as a result of the bond topology, with all three
(110) surfaces showing similar behavior.Comment: 13 pages, in revtex format, plus 1 postscript figur
Supermassive Binaries and Extragalactic Jets
Some quasars show Doppler shifted broad emission line peaks. I give new
statistics of the occurrence of these peaks and show that, while the most
spectacular cases are in quasars with strong radio jets inclined to the line of
sight, they are also almost as common in radio-quiet quasars. Theories of the
origin of the peaks are reviewed and it is argued that the displaced peaks are
most likely produced by the supermassive binary model. The separations of the
peaks in the 3C 390.3-type objects are consistent with orientation-dependent
"unified models" of quasar activity. If the supermassive binary model is
correct, all members of "the jet set" (astrophysical objects showing jets)
could be binaries.Comment: 31 pages, PostScript, missing figure is in ApJ 464, L105 (see
http://www.aas.org/ApJ/v464n2/5736/5736.html
Advances in ab-initio theory of Multiferroics. Materials and mechanisms: modelling and understanding
Within the broad class of multiferroics (compounds showing a coexistence of
magnetism and ferroelectricity), we focus on the subclass of "improper
electronic ferroelectrics", i.e. correlated materials where electronic degrees
of freedom (such as spin, charge or orbital) drive ferroelectricity. In
particular, in spin-induced ferroelectrics, there is not only a {\em
coexistence} of the two intriguing magnetic and dipolar orders; rather, there
is such an intimate link that one drives the other, suggesting a giant
magnetoelectric coupling. Via first-principles approaches based on density
functional theory, we review the microscopic mechanisms at the basis of
multiferroicity in several compounds, ranging from transition metal oxides to
organic multiferroics (MFs) to organic-inorganic hybrids (i.e. metal-organic
frameworks, MOFs)Comment: 22 pages, 9 figure
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