911 research outputs found
Culex tarsalis is a competent vector species for Cache Valley virus
Background: Cache Valley virus (CVV) is a mosquito-borne orthobunyavirus endemic in North America. The virus is
an important agricultural pathogen leading to abortion and embryonic lethality in ruminant species, especially
sheep. The importance of CVV in human public health has recently increased because of the report of severe
neurotropic diseases. However, mosquito species responsible for transmission of the virus to humans remain to be
determined. In this study, vector competence of three Culex species mosquitoes of public health importance, Culex
pipiens, Cx. tarsalis and Cx. quinquefasciatus, was determined in order to identify potential bridge vector species
responsible for the transmission of CVV from viremic vertebrate hosts to humans.
Results: Variation of susceptibility to CVV was observed among selected Culex species mosquitoes tested in this
study. Per os infection resulted in the establishment of infection and dissemination in Culex tarsalis, whereas Cx.
pipiens and Cx. quinquefasciatus were highly refractory to CVV. Detection of viral RNA in saliva collected from
infected Cx. tarsalis provided evidence supporting its role as a competent vector.
Conclusions: Our study provided further understanding of the transmission cycles of CVV and identifies Cx. tarsalis
as a competent vector
Distinct Mechanisms for Induction and Tolerance Regulate the Immediate Early Genes Encoding Interleukin 1β and Tumor Necrosis Factor α
Interleukin-1β and Tumor Necrosis Factor α play related, but distinct, roles in immunity and disease. Our study revealed major mechanistic distinctions in the Toll-like receptor (TLR) signaling-dependent induction for the rapidly expressed genes (IL1B and TNF) coding for these two cytokines. Prior to induction, TNF exhibited pre-bound TATA Binding Protein (TBP) and paused RNA Polymerase II (Pol II), hallmarks of poised immediate-early (IE) genes. In contrast, unstimulated IL1B displayed very low levels of both TBP and paused Pol II, requiring the lineage-specific Spi-1/PU.1 (Spi1) transcription factor as an anchor for induction-dependent interaction with two TLR-activated transcription factors, C/EBPβ and NF-κB. Activation and DNA binding of these two pre-expressed factors resulted in de novo recruitment of TBP and Pol II to IL1B in concert with a permissive state for elongation mediated by the recruitment of elongation factor P-TEFb. This Spi1-dependent mechanism for IL1B transcription, which is unique for a rapidly-induced/poised IE gene, was more dependent upon P-TEFb than was the case for the TNF gene. Furthermore, the dependence on phosphoinositide 3-kinase for P-TEFb recruitment to IL1B paralleled a greater sensitivity to the metabolic state of the cell and a lower sensitivity to the phenomenon of endotoxin tolerance than was evident for TNF. Such differences in induction mechanisms argue against the prevailing paradigm that all IE genes possess paused Pol II and may further delineate the specific roles played by each of these rapidly expressed immune modulators. © 2013 Adamik et al
The Effect of Unsuccessful Past Repurchases on Future Repurchasing Decisions
We find that managers are less likely to repurchase stocks when they lose money on past stock repurchases but find no robust evidence that past gains on repurchases influence future repurchasing activity. This asymmetric sensitivity is strongest for young CEOs and those with the shortest tenure. Also, future repurchases are more sensitive to past repurchase losses for CEOs whose previous lifetime experience with the stock market is unfavorable. The sensitivity of future repurchases to past losses costs firms, on average, about 3.7% per year. When this cost is decomposed into systematic and idiosyncratic components, we find that nearly half (1.8%) comes from mistiming idiosyncratic shocks. Past losses on repurchases have a significant and negative impact on the CEO’s future bonus and increase the likelihood that future CEO termination is involuntary. We also find that negative outcomes from past repurchases encourage the subsequent use of dividends. Our findings suggest that outcomes of past repurchases have economically significant consequences through both nonbehavioral (career concerns) and behavioral (snakebite effect) factors.
Includes supplemental appendix
The Pattern in Securitization and Executive Compensation: Evidence and Regulatory Implications
The Dodd-Frank financial reforms of 2010 promised to better align risk-reward incentives by, among other things, reducing imprudent securitzation (i.e., sales of financial assets) and excessive executive compensation. This would, in turn, promote systemic stability. To assess whether Dodd-Frank’s elaborate rules on securitization and compensation are likely to achieve this goal, we explore the connection between the two empirically. Using a unique dataset covering 1993-2009 — the largest of its kind — we find that securitizing banks (regulated depositaries) on average paid their CEOs twice as much as non-securitizing banks, a finding that is both statistically and economically significant. By contrast, non-bank (industrial) firms that securitized actually paid their CEOs less than non-securitizers. Because securitizing banks performed no better than other firms (non-securitizing banks or industrials), we find evidence of agency cost; because bank-originated securitizations performed especially poorly in the financial crisis, we find evidence of social cost. Our findings have important implications for Dodd-Frank, because its rules on securitization and compensation fail to account for the incentive effects of securitization by banks. Its compensation provisions are disconnected from controls on securitization, in particular its risk-retention (“skin in the game”) rules. Moreover, it focuses not on those who “originate” securitizations, such as the banks we study, but instead the “securitizers” who issue securities backed by the financial assets in question. Because banks originated many of the worst securitizations — and yet paid their CEOs more for doing so — Dodd-Frank may be aimed at the wrong segment of securitization. Simpler, better-tailored regulation that accounts for the pattern we observe would more likely achieve Dodd-Frank’s goals of systemic stability and accountability.Temple University. James E. Beasley School of La
Natural occurrence of Cucumber mosaic virus infecting water mint (Mentha aquatica) in Antalya and Konya, Turkey
A virus causing a disease in mint (the aromatic and culinary plant) has recently become a problem in the Taurus Mountains, a mountain range in the Mediterranean region of Turkey. To detect the virus and investigate its distribution in the region, mint leaf samples were collected from the vicinity of spring areas in the plateaus of Antalya and Konya in 2009. It was found that Cucumber mosaic virus (CMV) was detected in 27.08% of symptomatic samples tested by DAS-ELISA. To the best of our knowledge, this is the first report of CMV on mint plants in this region of Turkey
Combining vitamin C and carotenoid biomarkers better predicts fruit and vegetable intake than individual biomarkers in dietary intervention studies.
The aim of this study was to determine whether combining potential biomarkers of fruit and vegetables is better at predicting FV intake within FV intervention studies than single biomarkers
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Distribution of mosquitoes in the South East of Argentina and first report on the analysis based on 18S rDNA and COI sequences
Although Mar del Plata is the most important city on the Atlantic coast of Argentina, mosquitoes inhabiting such area are almost uncharacterized. To increase our knowledge in their distribution, we sampled specimens of natural populations. After the morphological identification based on taxonomic keys, sequences of DNA from small ribosomal subunit (18S rDNA) and cytochrome c oxidase I (COI) genes were obtained from native species and the phylogenetic analysis of these sequences were done. Fourteen species from the genera Uranotaenia, Culex, Ochlerotatus and Psorophora were found and identified. Our 18S rDNA and COI-based analysis indicates the relationships among groups at the supra-species level in concordance with mosquito taxonomy. The introduction and spread of vectors and diseases carried by them are not known in Mar del Plata, but some of the species found in this study were reported as pathogen vectors
Recurrent thrombosis in patients with antiphospholipid antibodies and arterial thrombosis on antithrombotic therapy
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