569 research outputs found

    Serological Prevalence of Schistosoma japonicum in Mobile Populations in Previously Endemic but Now Non-Endemic Regions of China: A Systematic Review and Meta-Analysis.

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    Background: Schistosomiasis japonica has been resurging in certain areas of China where its transmission was previously well controlled or interrupted. Several factors may be contributing to this, including mobile populations, which if infected, may spread the disease. A wide range of estimates have been published for S. japonicum infections in mobile populations, and a synthesis of these data will elucidate the relative risk presented from these groups. Methods: A literature search for publications up to Oct 31, 2014 on S. japonicum infection in mobile populations in previously endemic but now non-endemic regions was conducted using four bibliographic databases: China National Knowledge Infrastructure, WanFang, VIP Chinese Journal Databases, and PubMed. A meta-analysis was conducted by pooling one arm binary data with MetaAnalyst Beta 3.13. The protocol is available on PROSPERO (No. CRD42013005967). Results: A total of 41 studies in Chinese met the inclusion criteria, covering seven provinces of China. The time of post-interruption surveillance ranged from the first year to the 31st year. After employing a random-effects model, from 1992 to 2013 the pooled seroprevalence ranged from 0.9% (95% CI: 0.5-1.6%) in 2003 to 2.3% (95% CI: 1.5-3.4) in 1995; from the first year after the disease had been interrupted to the 31st year, the pooled seroprevalence ranged from 0.6% (95% CI: 0.2-2.1%) in the 27th year to 4.0% (95%CI: 1.3-11.3%) in the second year. The pooled seroprevalence in mobile populations each year was significantly lower than among the residents of endemic regions, whilst four papers reported a lower level of infection in the mobile populations than in the local residents out of only 13 papers which included this data. Conclusions: The re-emergence of S. japonicum in areas which had previously interrupted transmission might be due to other factors, although risk from re-introduction from mobile populations could not be excluded

    The contribution of cause-effect link to representing the core of scientific paper—The role of Semantic Link Network

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    The Semantic Link Network is a general semantic model for modeling the structure and the evolution of complex systems. Various semantic links play different roles in rendering the semantics of complex system. One of the basic semantic links represents cause-effect relation, which plays an important role in representation and understanding. This paper verifies the role of the Semantic Link Network in representing the core of text by investigating the contribution of cause-effect link to representing the core of scientific papers. Research carries out with the following steps: (1) Two propositions on the contribution of cause-effect link in rendering the core of paper are proposed and verified through a statistical survey, which shows that the sentences on cause-effect links cover about 65% of key words within each paper on average. (2) An algorithm based on syntactic patterns is designed for automatically extracting cause-effect link from scientific papers, which recalls about 70% of manually annotated cause-effect links on average, indicating that the result adapts to the scale of data sets. (3) The effects of cause-effect link on four schemes of incorporating cause-effect link into the existing instances of the Semantic Link Network for enhancing the summarization of scientific papers are investigated. The experiments show that the quality of the summaries is significantly improved, which verifies the role of semantic links. The significance of this research lies in two aspects: (1) it verifies that the Semantic Link Network connects the important concepts to render the core of text; and, (2) it provides an evidence for realizing content services such as summarization, recommendation and question answering based on the Semantic Link Network, and it can inspire relevant research on content computing

    Production of 1,3-propanediol from glycerol by engineered

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    1,3-Propanediol (1,3-PD) has versatile applications in polymers, cosmetics, foods and medicines. In order to consolidate the functions of glycerol dehydratase gene dhaB and 1,3-propanediol oxidoreductase gene dhaT and produce 1,3-PD from glycerol, the genes dhaB and dhaT from Klebsiellapneumoniae were inserted into a co-expression vector pACYCDuet-1 synchronously and the recombinant strain E. coli/pACYCDuet-dhaB-dhaT was obtained. Both enzymes were functionally coexpressed in E. coli at the presence of the selective pressure and the addition of the IPTG. The specificenzyme activity of DHAB and DHAT were 8.3 and 6.2 U/mg, respectively. When cultivated at 37°C for 30 h, the recombinant microorganisms produced 1,3-PD of 11.3 g with the consumption of 40 g glycerol per liter. The production of 1,3-PD by the strain E. coli/pACYCDuet-dhaB-dhaT was about 13-fold higher than the recombinant E. coli harboring the gene dhaB

    Dynamic update of shortest path tree in OSPF

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    2003-2004 > Academic research: refereed > Refereed conference paperVersion of RecordPublishe

    Suppression of Ca2+ syntillas increases spontaneous exocytosis in mouse adrenal chromaffin cells

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    A central concept in the physiology of neurosecretion is that a rise in cytosolic [Ca2+] in the vicinity of plasmalemmal Ca2+ channels due to Ca2+ influx elicits exocytosis. Here, we examine the effect on spontaneous exocytosis of a rise in focal cytosolic [Ca2+] in the vicinity of ryanodine receptors (RYRs) due to release from internal stores in the form of Ca2+ syntillas. Ca2+ syntillas are focal cytosolic transients mediated by RYRs, which we first found in hypothalamic magnocellular neuronal terminals. (scintilla, Latin for spark; found in nerve terminals, normally synaptic structures.) We have also observed Ca2+ syntillas in mouse adrenal chromaffin cells. Here, we examine the effect of Ca2+ syntillas on exocytosis in chromaffin cells. In such a study on elicited exocytosis, there are two sources of Ca2+: one due to influx from the cell exterior through voltage-gated Ca2+ channels, and that due to release from intracellular stores. To eliminate complications arising from Ca2+ influx, we have examined spontaneous exocytosis where influx is not activated. We report here that decreasing syntillas leads to an increase in spontaneous exocytosis measured amperometrically. Two independent lines of experimentation each lead to this conclusion. In one case, release from stores was blocked by ryanodine; in another, stores were partially emptied using thapsigargin plus caffeine, after which syntillas were decreased. We conclude that Ca2+ syntillas act to inhibit spontaneous exocytosis, and we propose a simple model to account quantitatively for this action of syntillas

    Binary Neutron-Star Systems: From the Newtonian Regime to the Last Stable Orbit

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    We report on the first calculations of fully relativistic binary circular orbits to span a range of separation distances from the innermost stable circular orbit (ISCO), deeply inside the strong field regime, to a distance (∌\sim 200 km) where the system is accurately described by Newtonian dynamics. We consider a binary system composed of two identical corotating neutron stars, with 1.43 M⊙M_\odot gravitational mass each in isolation. Using a conformally flat spatial metric we find solutions to the initial value equations that correspond to semi-stable circular orbits. At large distance, our numerical results agree exceedingly well with the Newtonian limit. We also present a self consistent determination of the ISCO for different stellar masses.Comment: 4 pages, 3 postscript figures. Data points added to fig 2; some issues clarified; references adde

    Prospects for gravitational-wave observations of neutron-star tidal disruption in neutron-star/black-hole binaries

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    For an inspiraling neutron-star/black-hole binary (NS/BH), we estimate the gravity-wave frequency f_td at the onset of NS tidal disruption. We model the NS as a tidally distorted, homogeneous, Newtonian ellipsoid on a circular, equatorial geodesic around a Kerr BH. We find that f_td depends strongly on the NS radius R, and estimate that LIGO-II (ca. 2006-2008) might measure R to 15% precision at 140 Mpc (about 1 event/yr under current estimates). This suggests that LIGO-II might extract valuable information about the NS equation of state from tidal-disruption waves.Comment: RevTeX, 4 pages, 2 EPS figures. Revised slightly, corrected typo

    Truncated post-Newtonian neutron star model

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    As a preliminary step towards simulating binary neutron star coalescing problem, we test a post-Newtonian approach by constructing a single neutron star model. We expand the Tolman-Oppenheimer-Volkov equation of hydrostatic equilibrium by the power of c−2c^{-2}, where cc is the speed of light, and truncate at the various order. We solve the system using the polytropic equation of state with index Γ=5/3,2\Gamma=5/3, 2 and 3, and show how this approximation converges together with mass-radius relations. Next, we solve the Hamiltonian constraint equation with these density profiles as trial functions, and examine the differences in the final metric. We conclude the second `post-Newtonian' approximation is close enough to describe general relativistic single star. The result of this report will be useful for further binary studies. (Note to readers) This paper was accepted for publication in Physical Review D. [access code dsj637]. However, since I was strongly suggested that the contents of this paper should be included as a section in our group's future paper, I gave up the publication.Comment: 5 pages, RevTeX, 3 eps figs, epsf.sty, accepted for publication in PRD (Brief Report), but will not appea

    Gravitational Radiation from Rotational Instabilities in Compact Stellar Cores with Stiff Equations of State

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    We carry out 3-D numerical simulations of the dynamical instability in rapidly rotating stars initially modeled as polytropes with n = 1.5, 1.0, and 0.5. The calculations are done with a SPH code using Newtonian gravity, and the gravitational radiation is calculated in the quadrupole limit. All models develop the global m=2 bar mode, with mass and angular momentum being shed from the ends of the bar in two trailing spiral arms. The models then undergo successive episodes of core recontraction and spiral arm ejection, with the number of these episodes increasing as n decreases: this results in longer-lived gravitational wave signals for stiffer models. This instability may operate in a stellar core that has expended its nuclear fuel and is prevented from further collapse due to centrifugal forces. The actual values of the gravitational radiation amplitudes and frequencies depend sensitively on the radius of the star R_{eq} at which the instability develops.Comment: 39 pages, uses Latex 2.09. To be published in the Dec. 15, 1996 issue of Physical Review D. 21 figures (bitmapped). Originals available in compressed Postscript format at ftp://zonker.drexel.edu/papers/bars

    Gravitational radiation from corotating binary neutron stars of incompressible fluid in the first post-Newtonian approximation of general relativity

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    We analytically study gravitational radiation from corotating binary neutron stars composed of incompressible, homogeneous fluid in circular orbits. The energy and the angular momentum loss rates are derived up to the first post-Newtonian (1PN) order beyond the quadrupole approximation including effects of the finite size of each star of binary. It is found that the leading term of finite size effects in the 1PN order is only O(GM∗/c2a∗)O(GM_{\ast}/c^2 a_{\ast}) smaller than that in the Newtonian order, where GM∗/c2a∗GM_{\ast}/c^2 a_{\ast} means the ratio of the gravitational radius to the mean radius of each star of binary, and the 1PN term acts to decrease the Newtonian finite size effect in gravitational radiation.Comment: 26 pages, revtex, 9 figures(eps), accepted for publication in Phys. Rev.
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