142 research outputs found

    Sea surface temperature and paleo-El Niño events in Santa Barbara Basin, AD 1841-1941

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    Like pages of a "natural coastal diary", successive layers of anoxic varved sediment in the central Santa Barbara Basin have been used by paleoceanographers to reconstruct aspects of past coastal climate. This report focuses on the end of the "Little Ice Age" (15th to 19th century) and on the beginning of this century, a period known to encompass extreme climate excursions and weather events in the Santa Barbara Basin and other parts of Southern California. El Niño events are known to disrupt Southern California's coastal ecosystems and to cause anomalous weather conditions, but El Niño events in Southern California before 1990 have been largely undocumented

    Infusion of five percent dextrose increases mortality and morbidity following six minutes of cardiac arrest in resuscitated dogs

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    The aim of this study was to assess the effect of dextrose administration during and following cardiac resuscitation on mortality and morbidity. Thirty-one dogs anesthetized with halothane were subjected to six minutes of ventricular fibrillation and were resuscitated with open chest cardiac message. All dogs were successfully resuscitated. Thirteen received no dextrose infusion and were fully ambulatory, eating and drinking at 24 hours. Ten of the 18 dogs receiving an infusion of 5% dextrose died before 24 hours and the eight that survived were profoundly impaired. Significantly greater neurologic deficits were recorded for dogs with higher blood glucose concentrations. We conclude that the inclusion of dextrose in fluids used in resuscitation increases mortality and morbidity.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26775/1/0000328.pd

    New Beta Cephei Stars from the KELT Project

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    We present the results of a search for Galactic β Cephei stars, which are massive pulsating stars with both pressure modes and mixed modes. Thus, these stars can serve as benchmarks for seismological studies of the interiors of massive stars. We conducted the search by performing a frequency analysis on the optical light curves of known O- and B-type stars with data from the Kilodegree Extremely Little Telescope exoplanet survey. We identify 113 β Cephei stars, of which 86 are new discoveries, which altogether represent a 70% increase in the number currently known. An additional 97 candidates are identified. Among our targets, we find five new eclipsing binaries and 22 stars with equal frequency spacings suggestive of rotational splitting of nonradial pulsation modes. Candidates for runaway stars among our targets and a number of interesting individual objects are discussed. Most of the known and newly discovered β Cephei stars will be observed by the Transiting Exoplanet Survey Satellite mission, providing by far the most comprehensive observational data set of massive main-sequence pulsating stars of sufficient quality for detailed asteroseismic studies. Future analysis of these light curves has the potential to dramatically increase our understanding of the structure of stellar interiors and the physical processes taking place therein

    A mathematical model for breath gas analysis of volatile organic compounds with special emphasis on acetone

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    Recommended standardized procedures for determining exhaled lower respiratory nitric oxide and nasal nitric oxide have been developed by task forces of the European Respiratory Society and the American Thoracic Society. These recommendations have paved the way for the measurement of nitric oxide to become a diagnostic tool for specific clinical applications. It would be desirable to develop similar guidelines for the sampling of other trace gases in exhaled breath, especially volatile organic compounds (VOCs) which reflect ongoing metabolism. The concentrations of water-soluble, blood-borne substances in exhaled breath are influenced by: (i) breathing patterns affecting gas exchange in the conducting airways; (ii) the concentrations in the tracheo-bronchial lining fluid; (iii) the alveolar and systemic concentrations of the compound. The classical Farhi equation takes only the alveolar concentrations into account. Real-time measurements of acetone in end-tidal breath under an ergometer challenge show characteristics which cannot be explained within the Farhi setting. Here we develop a compartment model that reliably captures these profiles and is capable of relating breath to the systemic concentrations of acetone. By comparison with experimental data it is inferred that the major part of variability in breath acetone concentrations (e.g., in response to moderate exercise or altered breathing patterns) can be attributed to airway gas exchange, with minimal changes of the underlying blood and tissue concentrations. Moreover, it is deduced that measured end-tidal breath concentrations of acetone determined during resting conditions and free breathing will be rather poor indicators for endogenous levels. Particularly, the current formulation includes the classical Farhi and the Scheid series inhomogeneity model as special limiting cases.Comment: 38 page

    New Beta Cephei Stars from the KELT Project

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    We present the results of a search for Galactic β Cephei stars, which are massive pulsating stars with both pressure modes and mixed modes. Thus, these stars can serve as benchmarks for seismological studies of the interiors of massive stars. We conducted the search by performing a frequency analysis on the optical light curves of known O- and B-type stars with data from the Kilodegree Extremely Little Telescope exoplanet survey. We identify 113 β Cephei stars, of which 86 are new discoveries, which altogether represent a 70% increase in the number currently known. An additional 97 candidates are identified. Among our targets, we find five new eclipsing binaries and 22 stars with equal frequency spacings suggestive of rotational splitting of nonradial pulsation modes. Candidates for runaway stars among our targets and a number of interesting individual objects are discussed. Most of the known and newly discovered β Cephei stars will be observed by the Transiting Exoplanet Survey Satellite mission, providing by far the most comprehensive observational data set of massive main-sequence pulsating stars of sufficient quality for detailed asteroseismic studies. Future analysis of these light curves has the potential to dramatically increase our understanding of the structure of stellar interiors and the physical processes taking place therein

    Transcriptomic and proteomic analysis of arbovirus-infected tick cells

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    Ticks are important vectors of a wide variety of pathogens including protozoa, bacteria and viruses. Many of the viruses transmitted by ticks are of medical or veterinary importance including tick-borne encephalitis virus (TBEV) and Crimean- Congo hemorrhagic fever virus causing disease in humans, and African swine fever virus and Nairobi sheep disease virus affecting livestock. Although several studies have elucidated tick antimicrobial mechanisms including cellular immune responses such as nodulation, encapsulation and phagocytosis and humoral immune responses such as the JAK/STAT pathway, complement-like proteins, antimicrobial peptides, lectin like pattern-recognition molecules and lysozymes, very little is known about the innate immune response of ticks towards viral infection. This study therefore aimed to identify molecules that might be involved in the response of ticks to viral infection. The hypothesis was that TBEV infection leads to changes in the expression of immunity-related transcripts and proteins in Ixodes spp. tick cells and that at least some of these might be antiviral. Ixodes scapularis-derived cell lines IDE8 and ISE6 were chosen since I. scapularis is currently the only tick species with a sequenced genome and an Ixodes ricinus-derived cell line, IRE/CTVM19, was used because I. ricinus is the natural vector of TBEV. Basic parameters required to study the responses of tick cells to infection were determined, including levels of virus infection, kinetics of virus replication and production, formation of replication complexes and uptake of dsRNA or siRNA. The cell lines IDE8, ISE6 and IRE/CTVM19 were infected with either of two tick-borne flaviviruses, TBEV and Langat virus (LGTV), or with the mosquito-borne alphavirus Semliki Forest virus (SFV). Infection was characterised using techniques including plaque assay, luciferase assay, immunostaining and conventional, confocal and electron microscopy. Two time points for transcriptomics and proteomics analysis of TBEVinfected IDE8 and IRE/CTVM19 cells were selected: day 2 post-infection (p.i.) when virus production was increasing and day 6 p.i. when virus production was decreasing. RNA and protein were isolated from TBEV-infected and mock-infected tick cells at days 2 and 6 p.i. and RNA-Seq and mass spectrometric technologies were used to identify changes in, respectively, transcript and protein abundance. Differential expression of transcripts was determined using the data analysis package DESeq resulting in a total of 43 statistically significantly differentially expressed transcripts in IDE8 cells and 83 in IRE/CTVM19 cells, while differential protein representation using Χ2 test statistics with Bonferroni correction in IDEG6 software resulted in 76 differentially represented proteins in IDE8 cells and 129 in IRE/CTVM19 cells. These included transcripts and proteins which could affect stages of the virus infection, including virus entry, replication, maturation and protein trafficking, and also innate immune responses such as phagocytosis, RNA interference (RNAi), the complement system, the ubiquitin-proteasome pathway, cell stress and the endoplasmic reticulum (ER) stress response. After verification of sequencing data by qRT-PCR, the ability of several of the identified transcripts or proteins to affect virus infection was determined by knockdown experiments in IDE8 and IRE/CTVM19 cells using wild type LGTV, LGTV replicons or TBEV replicons. Knockdown of genes encoding proteins including the ER chaperone gp96 and the heat-shock protein HSP90 resulted in increased virus production in both cell lines, hinting at an antiviral role. In contrast, knockdown of calreticulin, another ER chaperone, resulted in a decrease in virus production in IRE/CTVM19 cells but not in IDE8 cells, implying a requirement for virus production. This functional genomics approach has identified possible novel genes/proteins involved in the interaction between flaviviruses and tick cells and also revealed that there might be antiviral innate immune pathways present in ticks additional to the exogenous RNAi pathway

    Comparative Genomic Hybridization (CGH) Reveals a Neo-X Chromosome and Biased Gene Movement in Stalk-Eyed Flies (Genus Teleopsis)

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    Chromosomal location has a significant effect on the evolutionary dynamics of genes involved in sexual dimorphism, impacting both the pattern of sex-specific gene expression and the rate of duplication and protein evolution for these genes. For nearly all non-model organisms, however, knowledge of chromosomal gene content is minimal and difficult to obtain on a genomic scale. In this study, we utilized Comparative Genomic Hybridization (CGH), using probes designed from EST sequence, to identify genes located on the X chromosome of four species in the stalk-eyed fly genus Teleopsis. Analysis of log2 ratio values of female-to-male hybridization intensities from the CGH microarrays for over 3,400 genes reveals a strongly bimodal distribution that clearly differentiates autosomal from X-linked genes for all four species. Genotyping of 33 and linkage mapping of 28 of these genes in Teleopsis dalmanni indicate the CGH results correctly identified chromosomal location in all cases. Syntenic comparison with Drosophila indicates that 90% of the X-linked genes in Teleopsis are homologous to genes located on chromosome 2L in Drosophila melanogaster, suggesting the formation of a nearly complete neo-X chromosome from Muller element B in the dipteran lineage leading to Teleopsis. Analysis of gene movement both relative to Drosophila and within Teleopsis indicates that gene movement is significantly associated with 1) rates of protein evolution, 2) the pattern of gene duplication, and 3) the evolution of eyespan sexual dimorphism. Overall, this study reveals that diopsids are a critical group for understanding the evolution of sex chromosomes within Diptera. In addition, we demonstrate that CGH is a useful technique for identifying chromosomal sex-linkage and should be applicable to other organisms with EST or partial genomic information

    Mudança científica: modelos filosóficos e pesquisa histórica

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