517 research outputs found
Indices of Informational Association and Analysis of Complex Socio-Economic Systems
This paper is motivated by a distinctive appreciation of the difficulties posed by quantitative observational inquiry into complex social and economic systems. It develops ordinary and piecewise indices of joint and incremental informational association that enable robust approaches to a common problem in social inquiry: grappling with associations between a quantity of interest and two distinct sets of co-variates taking values over large numbers of individuals. The distinct analytical usefulness of these indices is illustrated with their application to inquiry into the systemic economic effects of patterns of discrimination by social identity in the U.S. economy
Autophagy in Pancreatic Cancer
Pancreatic adenocarcinoma (PDAC) is a devastating disease with an extremely poor life expectancy and no effective treatment. Autophagy is a process of degradation of cytoplasmic component capable of recycling cellular components or eliminate specific targets. The presence of autophagy in PDAC has been demonstrated. However, the implicated cellular pathways are not fully understood and, more importantly, the role of autophagy in PDAC is matter of intensive debate. This review summarizes recently published data in an attempt to clarify the importance of autophagy in this disease and try to reconcile apparently contradictory results
Spin injection in Silicon at zero magnetic field
In this letter, we show efficient electrical spin injection into a SiGe based
\textit{p-i-n} light emitting diode from the remanent state of a
perpendicularly magnetized ferromagnetic contact. Electron spin injection is
carried out through an alumina tunnel barrier from a Co/Pt thin film exhibiting
a strong out-of-plane anisotropy. The electrons spin polarization is then
analysed through the circular polarization of emitted light. All the light
polarization measurements are performed without an external applied magnetic
field \textit{i.e.} in remanent magnetic states. The light polarization as a
function of the magnetic field closely traces the out-of-plane magnetization of
the Co/Pt injector. We could achieve a circular polarization degree of the
emitted light of 3 % at 5 K. Moreover this light polarization remains almost
constant at least up to 200 K.Comment: accepted in AP
Drivers of ecosystem vulnerability to Corbicula invasions in southeastern North America
Financiado para publicación en acceso aberto: Universidade de Vigo/CISUGInvasive species introduction is one of the major ongoing ecological global crises. Identifying factors responsible for the success of invasive species is key for the implementation of effective management actions. The invasive filter-feeding bivalve, Corbicula, is of particular interest because it has become ubiquitous in many river basins across North America and elsewhere. Here we sampled bivalve assemblages, environmental indicators, and land cover parameters in the Ouachita highlands in southeastern Oklahoma and southwestern Arkansas, and in the Gulf Coastal Plain of Alabama to test three working models (using structural equation modeling, SEM) based on a priori scientific knowledge regarding Corbicula invasions. Our models tested three competing hypotheses: (1) Native mussel declines are related to land use changes at the watershed level and subsequent Corbicula colonization is a result of an empty niche; (2) Corbicula abundance is one of the factors responsible for native mussel declines and has an interactive effect with land use change at the watershed level; (3) Native mussel declines and Corbicula success are both related to land use changes at the watershed level. We found no evidence for the first two hypotheses. However, we found that environmental indicators and land cover parameters at the watershed scale were robust predictors of Corbicula abundance. In particular, agricultural land cover was positively related with Corbicula density. These results suggest that further improvement of conventional agricultural practices including the optimization of fertilizer delivery systems may represent an opportunity to manage this species by limiting nutrient inputs to stream ecosystems. Preservation of extensive floodplain habitats may help buffer these inputs by providing key ecosystem services including sediment and nutrient retention.National Science Foundation | Ref. DEB-1831512Xunta de Galicia | Ref. I2C 2017-202
Blood inflammatory indices in goats around kidding
AbstractThe transition period of goats is often characterized by serious metabolic problems, mainly before parturition. These troubles are related to negative energy balance status, however all causes are not totally defined. To improve the knowledge about pathogenesis in this phase we have monitored the changes of some blood indices of lipomobilization and inflammation. Six blood samples were collected from 10 primiparous and 25 multiparous "Camosciata delle Alpi" goats after morning milking. Samples were collected around 20 and 7 days before parturition and on days 0, 3, 6 and 12 of lactation. Albumin, total protein, haptoglobin, ceruloplasmin, total cholesterol, NEFA, β-OH-butyrate (BHB), Ca, Mg and Zn were determined. Goats were grouped according to their BHB level before parturition: low (≤0.6 mmol/l; LOB), average (0.6÷1.09; AVB) and high (≥1.09 mmol/l; HIB) level. Furthermore, the AVB group was divided according to plasma haptoglobin level before parturition: low (<0.5 g/l) or high. The statistical..
Theory of repulsive charged colloids in slit-pores
9 pags., 8 figs., 1 tab.Using classical density functional theory (DFT) we analyze the structure of the density profiles and solvation pressures of negatively charged colloids confined in slit pores. The considered model, which was already successfully employed to study a real colloidal (silica) suspension [S. H. L. Klapp, Phys. Rev. Lett. 100, 118303 (2008)10.1103/PhysRevLett.100.118303], involves only the macroions which interact via the effective Derjaguin-Landau-Verwey-Overbeek (DLVO) potential supplemented by a hard core interaction. The solvent enters implicitly via the screening length of the DLVO interaction. The free energy functional describing the colloidal suspension consists of a hard sphere contribution obtained from fundamental measure theory and a long range contribution which is treated using two types of approximations. One of them is the mean field approximation (MFA) and the remaining is based on Rosenfelds perturbative method for constructing the Helmholtz energy functional. These theoretical calculations are carried out at different bulk densities and wall separations to compare finally to grand canonical Monte Carlo simulations. We also consider the impact of charged walls. Our results show that the perturbative DFT method yields generally qualitatively consistent and, for some systems, also quantitatively reliable results. In MFA, on the other hand, the neglect of charge-induced correlations leads to a breakdown of this approach in a broad range of densities. © 2012 American Institute of Physics.A.G. and N.G.A. acknowledge financial support from the Dirección General de Investigación Científica
y Técnica under Grant No. FIS2010-15502, and from the
Dirección General de Universidades e Investigación de la Comunidad de Madrid under Grant No. S2009/ESP-1691 and
Program MODELICO-CM. S.G. and S.H.L.K. would like
to thank the German Research Foundation (DFG) for financial support within the Collaborative Research Center (CRC)
951 “Hybrid Inorganic/organic systems for Optoelectronics”
and the International Graduate School (IRTG) 1524 “Selfassembled soft-matter nanostructures at interfaces.
A Coverage Criterion for Spaced Seeds and its Applications to Support Vector Machine String Kernels and k-Mer Distances
Spaced seeds have been recently shown to not only detect more alignments, but
also to give a more accurate measure of phylogenetic distances (Boden et al.,
2013, Horwege et al., 2014, Leimeister et al., 2014), and to provide a lower
misclassification rate when used with Support Vector Machines (SVMs) (On-odera
and Shibuya, 2013), We confirm by independent experiments these two results,
and propose in this article to use a coverage criterion (Benson and Mak, 2008,
Martin, 2013, Martin and No{\'e}, 2014), to measure the seed efficiency in both
cases in order to design better seed patterns. We show first how this coverage
criterion can be directly measured by a full automaton-based approach. We then
illustrate how this criterion performs when compared with two other criteria
frequently used, namely the single-hit and multiple-hit criteria, through
correlation coefficients with the correct classification/the true distance. At
the end, for alignment-free distances, we propose an extension by adopting the
coverage criterion, show how it performs, and indicate how it can be
efficiently computed.Comment: http://online.liebertpub.com/doi/abs/10.1089/cmb.2014.017
Fructooligosaccharides and β-fructofuranosidase production by Aspergillus japonicus immobilized on lignocellulosic materials
This work describes the fructooligosaccharides (FOS) and β-fructofuranosidase (FFase) production from sucrose (200 g/l) by Aspergillus japonicus ATCC 20236 immobilized on different lignocellulosic materials including brewer's spent grain, wheat straw, corn cobs, coffee husks, cork oak, and loofa sponge. Transfructosylating (Ut) and hydrolyzing (Uh) activities of FFase were also determined. The FOS production and FFase activity ranged from 128.35 to 138.73 g/l, and 26.83 to 44.81 U/ml, respectively, for cells immobilized in the different carriers. Corn cobs was the best support material since gave the highest results of microorganism immobilization (1.49 g/g carrier), FOS and FFase production, with FOS productivity (6.61 g/l h) and yield (0.66 g/g based on total substrate; 0.73 g/g based on consumed substrate) higher than those obtained by free cells system. Moreover, the ratio Ut/Uh of FFase, parameter of importance for elevated FOS production, was greater for cells immobilized in corn cobs than for free cells. Such results demonstrated that corn cobs can be successfully used as carrier for immobilization of the fungus A. japonicus, for the production of FOS and FFase.Fundação para a Ciência e a Tecnologia (FCT
Colonization of Aspergillus japonicus on synthetic materials and application to the production of fructooligosaccharides
The ability of Aspergillus japonicus ATCC 20236 to colonize different synthetic materials (polyurethane foam, stainless steel sponge, vegetal fiber, pumice stones, zeolites, and foam glass) and to produce fructooligosaccharides (FOS) from sucrose (165 g/L) is described. Cells were immobilized in situ by absorption, through direct contact with the carrier particles at the beginning of fermentation. Vegetal fiber was the best immobilization carrier as A. japonicus grew well on it (1.25 g/g carrier), producing 116.3 g/L FOS (56.3 g/L 1-kestose, 46.9 g/L 1-nystose, and 13.1 g/L 1-β-fructofuranosyl nystose) with 69% yield (78% based only in the consumed sucrose amount), giving also elevated activity of the β-fructofuranosidase enzyme (42.9 U/mL). In addition, no loss of material integrity, over a 2 day-period, was found. The fungus also immobilized well on stainless steel sponge (1.13 g/g carrier), but in lesser extents on polyurethane foam, zeolites, and pumice stones (0.48, 0.19, and 0.13 g/g carrier, respectively), while on foam glass no cell adhesion was observed. When compared with the FOS and β-fructofuranosidase production by free A. japonicus, the results achieved using cells immobilized on vegetal fiber were closely similar. It was thus concluded that A. japonicus immobilized on vegetal fiber is a potential alternative for high production of FOS at industrial scale.Fundação para a Ciência e a Tecnologia (FCT
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