312 research outputs found

    Gradients of Taxonomic Diversity among Local Floras in the Russian Arctic

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    Latitudinal and longitudinal changes in taxonomic variables were analyzed in 319 local floras in the Russian Arctic. Within the studied segment of latitudinal gradient, most changes can be described in terms of linear regression with negative coefficients (a number of species, genera and families), or positive coefficients (a proportion of the leading families and genera). However, the mean number of species in a family or genus almost does not change with increasing latitude, although it slightly increases as one moves eastward. The proportion of monocots does not correlate with latitude, but slightly decreases as one moves eastward. Proportions of various families change asynchronously. Although correlation with longitude was less pronounced, mean species richness was specific to many subprovinces, even within a certain subzone. These differences reflect both the diversity of landscapes and the history of flora formation. Keywords: the Arctic, local floras, latitudinal and longitudinal gradient, floristic subprovince

    Null Energy Condition Violation and Classical Stability in the Bianchi I Metric

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    The stability of isotropic cosmological solutions in the Bianchi I model is considered. We prove that the stability of isotropic solutions in the Bianchi I metric for a positive Hubble parameter follows from their stability in the Friedmann-Robertson-Walker metric. This result is applied to models inspired by string field theory, which violate the null energy condition. Examples of stable isotropic solutions are presented. We also consider the k-essence model and analyse the stability of solutions of the form Φ(t)=t\Phi(t)=t.Comment: 27 pages, references added, accepted for publication in Phys. Rev.

    Changes in cytokine production in healthy subjects practicing Guolin Qigong : a pilot study

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    BACKGROUND: Guolin Qigong is a combination of meditation, controlled breathing and physical movement designed to control the vital energy (qi) of the body and consequently to improve spiritual, physical and mental health. Practice of Qigong has been reported to alter immunological function, but there have been few studies of its effects on cytokines, the key regulators of immunity. METHODS: Numbers of peripheral blood cytokine-secreting cells were determined by ELISPOT in 19 healthy volunteers aged 27 – 55, before they were taught the practice of Qigong and after 3, 7 and 14 weeks of daily practice. The effect of Qigong on blood cortisol was also examined. RESULTS: Numbers of IL4 and IL12-secreting cells remained stable. IL6 increased at 7 weeks and TNFα increased in unstimulated cultures at 3 and 7 weeks but decreased at these times in LPS and SAC-stimulated cultures. Of particular interest, IFNγ-secreting cells increased and IL10-secreting cells decreased in PHA-stimulated cultures, resulting in significant increases in the IFNγ:IL10 ratio. Cortisol, a known inhibitor of type 1 cytokine production, was reduced by practicing Qigong. CONCLUSION: These preliminary studies in healthy subjects, although not necessarily representative of a randomized healthy population and not including a separate control group, have indicated that blood levels of the stress-related hormone cortisol may be lowered by short-term practice of Qigong and that there are concomitant changes in numbers of cytokine-secreting cells. Further studies of the effect of Qigong in patients with clinical diseases known to be associated with type 2 cytokine predominance are merited

    Antegrade lithoextraction as perspective technique for mechanical jaundice radical treatment

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    Objective. Improvement of treatment outcomes in patients with the cholelithiasis complicated by mechanical jaundice when it is impossible to apply retrograde techniques for biliary tract decompression.Material and Methods. From 2014 to 2017 in our hospital 1158 patients with cholelithiasis complicated by mechanical jaundice have been treated. The group consisted of 59 (5.1%) patients with initially predicted difficulties for endoscopic lithoextraction. In 12 of that group antegrade decompression was the only surgical method for completing treatment. In 2 cases the ‘rendezvous’ technique was used, and in 23 patients the antegrade decompression it was complemented with laparotomy and choledocholithotomy. In 22 patients for verification the nature of the bile-excreting ducts and the cholelithic occlusion revealed at the same time the first stage included an antegrade decompression that allowed to finish surgical treatment by an endoscopic transpapillary lithoextraction.Results. In the main group of clinical observations for 59 patients the surgical treatment complemented with an antegrade decompression was without fatal outcomes. All patients were cured of cholelithic occlusion and recovered. In the study group with 1099 patients that were treated with only an endoscopic lithoextraction 8 patients died that showed 0.7 ± 0.2% of operational mortality. Complications, in the form of operational wounds in the main group of observations were found in 7 patients and it was 11.8 ± 4.2%. Other postoperative complications in the main group were not observed. In the control group similar wound complications were seen in 13 patients (1.2%). In the control group with 57 patients we observed intraabdominal complications which resulted in mortality (5.2 ± 0.7%). Of those postoperative reversible pancreatitis was found in 34 patients, 3 patients had fulminant pancreonecrosis, in 4 cases there was profuse bleeding from a papillosphincterotomy area, in 3 cases we observed insertion of Dormia basket at lithoextraction, septic cholangitis was in 11 and duodenum perforation with retroperitoneal phlegmon was in 3 cases.Conclusion. Mortality in the group with antegrade treatment application for choledocholithiasis was not found. On the contrary, rather higher rate of complications in the control group testifies in advantage of the antegrade techniques for choledocholithiasis treatment in the shown cases

    An inactivated Vero cell-grown Japanese encephalitis vaccine formulated with Advax, a novel inulin-based adjuvant, induces protective neutralizing antibody against homologous and heterologous flaviviruses

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    Advax is a polysaccharide-based adjuvant that potently stimulates vaccine immunogenicity without the increased reactogenicity seen with other adjuvants. This study investigated the immunogenicity of a novel Advax-adjuvanted Vero cell culture candidate vaccine against Japanese encephalitis virus (JEV) in mice and horses. The results showed that, in mice, a two-immunization, low-dose (50 ng JEV antigen) regimen with adjuvanted vaccine produced solid neutralizing immunity comparable to that elicited with live ChimeriVax-JE immunization and superior to that elicited with tenfold higher doses of a traditional non-adjuvanted JEV vaccine (JE-VAX; Biken Institute) or a newly approved alum-adjuvanted vaccine (Jespect; Novartis). Mice vaccinated with the Advax-adjuvanted, but not the unadjuvanted vaccine, were protected against live JEV challenge. Equine immunizations against JEV with Advax-formulated vaccine similarly showed enhanced vaccine immunogenicity, confirming that the adjuvant effects of Advax are not restricted to rodent models. Advax-adjuvanted JEV vaccine elicited a balanced T-helper 1 (Th1)/Th2 immune response against JEV with protective levels of cross-neutralizing antibody against other viruses belonging to the JEV serocomplex, including Murray Valley encephalitis virus (MVEV). The adjuvanted JEV vaccine was well tolerated with minimal reactogenicity and no systemic toxicity in immunized animals. The cessation of manufacture of traditional mouse brain-derived unadjuvanted JEV vaccine in Japan has resulted in a JEV vaccine shortage internationally. There is also an ongoing lack of human vaccines against other JEV serocomplex flaviviruses, such as MVEV, making this adjuvanted, cell culture-grown JEV vaccine a promising candidate to address both needs with one vaccine

    Invariant construction of solutions to Einstein's field equations - LRS perfect fluids II

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    The properties of LRS class II perfect fluid space-times are analyzed using the description of geometries in terms of the Riemann tensor and a finite number of its covariant derivatives. In this manner it is straightforward to obtain the plane and hyperbolic analogues to the spherical symmetric case. For spherically symmetric static models the set of equations is reduced to the Tolman-Oppenheimer-Volkoff equation only. Some new non-stationary and inhomogeneous solutions with shear, expansion, and acceleration of the fluid are presented. Among these are a class of temporally self-similar solutions with equation of state given by p=(γ1)μ,1<γ<2p=(\gamma-1)\mu, 1<\gamma<2, and a class of solutions characterized by σ=Θ/6\sigma=-\Theta/6. We give an example of geometry where the Riemann tensor and the Ricci rotation coefficients are not sufficient to give a complete description of the geometry. Using an extension of the method, we find the full metric in terms of curvature quantities.Comment: 24 pages, 1 figur

    Identifying author heritage using surname data : an application for Russian surnames

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    This research article puts forward a method to identify the national heritage of authors based on the morphology of their surnames. Most studies in the field use variants of dictionary-based surname methods to identify ethnic communities, an approach that suffers from methodological limitations. Using the public file of ORCID (Open Researcher and Contributor ID) identifiers in 2015, we developed a surname-based identification method and applied it to infer Russian heritage from suffix-based morphological regularities. The method was developed conceptually and tested in an undersampled control set. Identification based on surname morphology was then complemented by using first-name data to eliminate false-positive results. The method achieved 98% precision and 94% recall rates—superior to most other methods that use name data. The procedure can be adapted to identify the heritage of a variety of national groups with morphologically regular naming traditions. We elaborate on how the method can be employed to overcome long-standing limitations of using name data in bibliometric datasets. This identification method can contribute to advancing research in scientific mobility and migration, patenting by certain groups, publishing and collaboration, transnational and scientific diaspora links, and the effects of diversity on the innovative performance of organizations, regions, and countries

    Erythropoietins (Epostim®) during chemoradiotherapy for malignancies in anemic patients

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    Anemia in female patients with solid neoplasms is corrected to normalize hemoglobin levels, to increase quality of life, and to improve antitumor therapy tolerance. The clinical application of recombinant human erythropoietin preparations has become an important treat- ment step that permits multiple hemotransfusions to be avoided. Epostim is effective and safe in increasing hemoglobin and packed cell volume and in overcoming the additive toxicity of chemo- and radiotherapy
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