6,552 research outputs found
Entering the Union : European accession and capacity-building priorities
The authors examine the impact of trade facilitation on bilateral trade flows. They examine trade facilitation and capacity-building priorities in 12 countries in the Europe and Central Asia region-eight of the current members of the European Union: Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Slovakia,and Slovenia, and three candidate members: Bulgaria, Romania, and Turkey. The results suggest that behind-the-border factors play an important role in determining bilateral trade flows (controlling for the effects of tariffs, development levels, distance, and regional characteristics of exporters and importers, among other factors). The development of new data sets to expand work related to trade facilitation, including strengthening the empirical work explored here, is a key priority without which intelligent policy and priorities cannot be made. The authors'analysis is based on data from the World Economic Forum, Global Competitiveness Report 2001-2002, World Competitiveness Yearbook 2000, and Kaufmann, Kraay, and Zoido-Lobaton (2002). The results indicate that more gains in exports than in imports are expected should the values of three out of the four indicators (port efficiency, regulatory regimes, and information technology infrastructure) of the new and candidate member countries improve halfway to the EU15 average. These countries would expect large trade gains as well as improvements in trade balances as their integration into the EU continues. For example, the greatest absolute trade gains-62 billion respectively-could be expected if their port efficiency and information technology infrastructure reach half the average level of the EU, and 70 percent of trade gains are associated with export expansion.Economic Theory&Research,Trade and Regional Integration,Trade Policy,Transport and Trade Logistics,Common Carriers Industry
Communication Efficient Distributed Newton Method with Fast Convergence Rates
We propose a communication and computation efficient second-order method for
distributed optimization. For each iteration, our method only requires
communication complexity, where is the problem dimension.
We also provide theoretical analysis to show the proposed method has the
similar convergence rate as the classical second-order optimization algorithms.
Concretely, our method can find~-second-order stationary points for nonconvex problem
by iterations, where is
the Lipschitz constant of Hessian. Moreover, it enjoys a local superlinear
convergence under the strongly-convex assumption. Experiments on both convex
and nonconvex problems show that our proposed method performs significantly
better than baselines.Comment: Accepted in SIGKDD 202
Laser-induced Collisional Detachment
A theoretical study is presented of the process of photodetachment of a negative ion by sub-threshold-frequency radiation in the presence of a simultaneous collision. Calculations are carried out for the H−-He case and the resulting cross section is compared with other competing processes, such as two-photon photodetachment and nonradiative collisional detachment
Deep Chandra Monitoring Observations of NGC 4649: II. Wide-Field Hubble Space Telescope Imaging of the Globular Clusters
We present g and z photometry and size estimates for globular clusters (GCs)
in the massive Virgo elliptical NGC 4649 (M60) using a five-pointing Hubble
Space Telescope/Advanced Camera for Surveys mosaic. The metal-poor GCs show a
monotonic negative metallicity gradient of (-0.43 +/- 0.10) dex per dex in
radius over the full radial range of the data, out to ~ 24 kpc. There is
evidence for substantial color substructure among the metal-rich GCs. The
metal-poor GCs have typical sizes ~ 0.4 pc larger than the metal-rich GCs out
to large galactocentric distances (~> 20 kpc), favoring an intrinsic
explanation for the size difference rather than projection effects. There is no
clear relation between half-light radius and galactocentric distance beyond ~
15 kpc, suggesting that the sizes of GCs are not generically set by tidal
limitation. Finally, we identify ~ 20 candidate ultra-compact dwarfs that
extend down to surprisingly faint absolute magnitudes (M_z ~ -8.5), and may
bridge the gap between this class and "extended clusters" in the Local Group.
Three of the brighter candidates have published radial velocities and can be
confirmed as bona fide ultra-compact dwarfs; follow-up spectroscopy will
determine the nature of the remainder of the candidates.Comment: ApJ in press. For redacted long table 1, see:
http://www.pa.msu.edu/~strader/4649/table.te
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Fob1 and Fob2 Proteins Are Virulence Determinants of Rhizopus oryzae via Facilitating Iron Uptake from Ferrioxamine.
Dialysis patients with chronic renal failure receiving deferoxamine for treating iron overload are uniquely predisposed for mucormycosis, which is most often caused by Rhizopus oryzae. Although the deferoxamine siderophore is not secreted by Mucorales, previous studies established that Rhizopus species utilize iron from ferrioxamine (iron-rich form of deferoxamine). Here we determined that the CBS domain proteins of Fob1 and Fob2 act as receptors on the cell surface of R. oryzae during iron uptake from ferrioxamine. Fob1 and Fob2 cell surface expression was induced in the presence of ferrioxamine and bound radiolabeled ferrioxamine. A R. oryzae strain with targeted reduced Fob1/Fob2 expression was impaired for iron uptake, germinating, and growing on medium with ferrioxamine as the sole source of iron. This strain also exhibited reduced virulence in a deferoxamine-treated, but not the diabetic ketoacidotic (DKA), mouse model of mucormycosis. The mechanism by which R. oryzae obtains iron from ferrioxamine involves the reductase/permease uptake system since the growth on ferrioxamine supplemented medium is associated with elevated reductase activity and the use of the ferrous chelator bathophenanthroline disulfonate abrogates iron uptake and growth on medium supplemented with ferrioxamine as a sole source of iron. Finally, R. oryzae mutants with reduced copies of the high affinity iron permease (FTR1) or with decreased FTR1 expression had an impaired iron uptake from ferrioxamine in vitro and reduced virulence in the deferoxamine-treated mouse model of mucormycosis. These two receptors appear to be conserved in Mucorales, and can be the subject of future novel therapy to maintain the use of deferoxamine for treating iron-overload
Gene family encoding the major toxins of lethal \u3ci\u3eAmanita\u3c/i\u3e mushrooms
Amatoxins, the lethal constituents of poisonous mushrooms in the genus Amanita, are bicyclic octapeptides. Two genes in A. bisporigera, AMA1 and PHA1, directly encode α-amanitin, an amatoxin, and the related bicyclic heptapeptide phallacidin, a phallotoxin, indicating that these compounds are synthesized on ribosomes and not by nonribosomal peptide synthetases. α-Amanitin and phallacidin are synthesized as proproteins of 35 and 34 amino acids, respectively, from which they are predicted to be cleaved by a prolyl oligopeptidase. AMA1 and PHA1 are present in other toxic species of Amanita section Phalloidae but are absent from nontoxic species in other sections. The genomes of A. bisporigera and A. phalloides contain multiple sequences related to AMA1 and PHA1. The predicted protein products of this family of genes are characterized by a hypervariable ‘‘toxin’’ region capable of encoding a wide variety of peptides of 7–10 amino acids flanked by conserved sequences. Our results suggest that these fungi have a broad capacity to synthesize cyclic peptides on ribosomes
Active and Passive Immunization with rHyr1p-N Protects Mice against Hematogenously Disseminated Candidiasis
We previously reported that Candida albicans cell surface protein Hyr1 encodes a phagocyte killing resistance factor and active vaccination with a recombinant N-terminus of Hyr1 protein (rHyr1p-N), significantly protects immunocompetent mice from disseminated candidiasis. Here we report the marked efficacy of rHyr1p-N vaccine on improving the survival and reducing the fungal burden of disseminated candidiasis in both immunocompetent and immunocompromised mice using the FDA-approved adjuvant, alum. Importantly, we also show that pooled rabbit anti-Hyr1p polyclonal antibodies raised against 8 different peptide regions of rHyr1p-N protected mice in a hematogenously disseminated candidiasis model, raising the possibility of developing a successful passive immunotherapy strategy to treat this disease. Our data suggest that the rabbit anti-Hyr1p antibodies directly neutralized the Hyr1p virulence function, rather than enhanced opsonophagocytosis for subsequent killing by neutrophil in vitro. Finally, the rHyr1p-N vaccine was protective against non-albicans Candida spp. These preclinical data demonstrate that rHyr1p-N is likely to be a novel target for developing both active and passive immunization strategies against Candida infections
Characterization of microRNA expression in bovine adipose tissues: a potential regulatory mechanism of subcutaneous adipose tissue development
<p>Abstract</p> <p>Background</p> <p>MicroRNAs (miRNAs), a family of small non-coding RNA molecules, appear to regulate animal lipid metabolism and preadipocyte conversion to form lipid-assimilating adipocytes (<it>i.e. </it>adipogenesis). However, no miRNA to date has been reported to modulate adipogenesis and lipid deposition in beef cattle.</p> <p>Results</p> <p>The expression patterns of 89 miRNAs including four bovine specific miRNAs in subcutaneous adipose tissues from three groups of crossbred steers differing in backfat thickness were compared using qRT-PCR analysis. Eighty-six miRNAs were detectable in all samples, with 42 miRNAs differing among crossbreds (P < 0.05) and 15 miRNAs differentially expressed between tissues with high and low backfat thickness (P < 0.05). The expression levels of 18 miRNAs were correlated with backfat thickness (P < 0.05). The miRNA most differentially expressed and the most strongly associated with backfat thickness was miR-378, with a 1.99-fold increase in high backfat thickness tissues (r = 0.72).</p> <p>Conclusions</p> <p>MiRNA expression patterns differed significantly in response to host genetic components. Approximately 20% of the miRNAs in this study were identified as being correlated with backfat thickness. This result suggests that miRNAs may play a regulatory role in white adipose tissue development in beef animals.</p
Batch Fabrication of High-Performance Planar Patch-Clamp Devices in Quartz
The success of the patch-clamp technique has driven an effort to create wafer-based patch-clamp platforms. We develop a lithographic/electrochemical processing scheme that generates ultrasmooth, high aspect ratio pores in quartz. These devices achieve gigaohm seals in nearly 80% of trials, with the majority exhibiting seal resistances from 20-80 GΩ, competing with pipette-based patch-clamp measurements
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