228 research outputs found

    How do uncertainties in NCEP R2 and CFSR surface fluxes impact tropical ocean simulations?

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    Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Climate Dynamics 49 (2017): 3327–3344, doi:10.1007/s00382-016-3516-6.NCEP/DOE reanalysis (R2) and Climate Forecast System Reanalysis (CFSR) surface fluxes are widely used by the research community to understand surface flux climate variability, and to drive ocean models as surface forcings. However, large discrepancies exist between these two products, including (1) stronger trade winds in CFSR than in R2 over the tropical Pacific prior 2000; (2) excessive net surface heat fluxes into ocean in CFSR than in R2 with an increase in difference after 2000. The goals of this study are to examine the sensitivity of ocean simulations to discrepancies between CFSR and R2 surface fluxes, and to assess the fidelity of the two products. A set of experiments, where an ocean model was driven by a combination of surface flux component from R2 and CFSR, were carried out. The model simulations were contrasted to identify sensitivity to different component of the surface fluxes in R2 and CFSR. The accuracy of the model simulations was validated against the tropical moorings data, altimetry SSH and SST reanalysis products. Sensitivity of ocean simulations showed that temperature bias difference in the upper 100m is mostly sensitive to the differences in surface heat fluxes, while depth of 20°C (D20) bias difference is mainly determined by the discrepancies in momentum fluxes. D20 simulations with CFSR winds agree with observation well in the western equatorial Pacific prior 2000, but have large negative bias similar to those with R2 winds after 2000, partly because easterly winds over the central Pacific were underestimated in both CFSR and R2. On the other hand, the observed temperature variability is well reproduced in the tropical Pacific by simulations with both R2 and CFSR fluxes. Relative to the R2 fluxes, the CFSR fluxes improve simulation of interannual variability in all three tropical oceans to a varying degree. The improvement in the tropical Atlantic is most significant and is largely attributed to differences in surface winds

    Heterogeneous Vancomycin-Intermediate Staphylococcus aureus Uses the VraSR Regulatory System to Modulate Autophagy for Increased Intracellular Survival in Macrophage-Like Cell Line RAW264.7

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    The VraSR two-component system is a vancomycin resistance-associated sensor/regulator that is upregulated in vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) strains. VISA/hVISA show reduced susceptibility to vancomycin and an increased ability to evade host immune responses, resulting in enhanced clinical persistence. However, the underlying mechanism remains unclear. Recent studies have reported that S. aureus strains have developed some strategies to survive within the host cell by using autophagy processes. In this study, we confirmed that clinical isolates with high vraR expression showed increased survival in murine macrophage-like RAW264.7 cells. We constructed isogenic vraSR deletion strain Mu3ΔvraSR and vraSR-complemented strain Mu3ΔvraSR-C to ascertain whether S. aureus uses the VraSR system to modulate autophagy for increasing intracellular survival in RAW264.7. Overall, the survival of Mu3ΔvraSR in RAW264.7 cells was reduced at all infection time points compared with that of the Mu3 wild-type strain. Mu3ΔvraSR-infected RAW264.7 cells also showed decreased transcription of autophagy-related genes Becn1 and Atg5, decreased LC3-II turnover and increased p62 degradation, and fewer visible punctate LC3 structures. In addition, we found that inhibition of autophagic flux significantly increased the survival of Mu3ΔvraSR in RAW264.7 cells. Together, these results demonstrate that S. aureus uses the VraSR system to modulate host-cell autophagy processes for increasing its own survival within macrophages. Our study provides novel insights into the impact of VraSR on bacterial infection and will help to further elucidate the relationship between bacteria and the host immune response. Moreover, understanding the autophagic pathway in vraSR associated immunity has potentially important implications for preventing or treating VISA/hVISA infection

    Combination with Methotrexate and Cyclophosphamide Attenuated Maturation of Dendritic Cells: Inducing Treg Skewing and Th17 Suppression In Vivo

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    Immune disorder is considered the main pathogenesis of autoimmune diseases, such as rheumatoid arthritis (RA). The balance of the two special subsets of CD4+T cells, T helper cell 17 (Th17), and Regulator T cell (Treg) is the key factor of maintaining a normal immune response. Dendritic cells (DCs), which are the most powerful antigen-presenting cells, play an important role in regulating the balance of Th17 and Treg. The combination of disease modifying antirheumatic drugs (DMARDs) is an important strategy of RA therapy. In this study, we investigated the effect of MTX and CTX on DC maturation in ovalbumin (OVA) immunized mice. Th17 inflammatory response is stronger, while the level of DCs maturity is higher. In contrast, the immunosuppression of Treg is stronger. We found that MTX combined with CTX significantly inhibited the DCs maturity and downregulated the antigen presenting capacity of DCs. As a result, it reestablished a balance of Th17 and Treg. Our study adds a novel mechanism and therapeutic target of MTX combined with CTX for autoimmune disease treatment

    Matriks Jordan Dan Aplikasinya Pada Sistem Linier Waktu Diskrit

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    Matrix is diagonalizable (similar with matrix diagonal) if and only if the sum of geometric multiplicities of its eigenvalues is n.If we search for an upper triangular form that is nearly diagonal as possible but is still attainable by similarity for every matrix, especially the sum of geometric multiplicities of its eigenvalues is less than n, the result is the Jordan canonical form, which is denoted by , and . In this paper, will be described how to get matrix S(in order to get matrix ) by using generalized eigenvector. In addition, it will also describe the Jordan canonical form and its properties, and some observation and application on discrete time linear system

    The global ocean water cycle in atmospheric reanalysis, satellite, and ocean salinity

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    This study provides an assessment of the uncertainty in ocean-surface (OS) freshwater budgets and variability using evaporation (E) and precipitation (P) from 10 atmospheric reanalyses, 2 combined satellite-based E-P products, and 2 observation-based salinity products. Three issues are examined: the uncertainty level in the OS freshwater budget in atmospheric reanalyses, the uncertainty structure and association with the global ocean wet/dry zones, and the potential of salinity in ascribing the uncertainty in E-P. The products agree on the global mean pattern but differ considerably in magnitude. The OS freshwater budgets are 129±10 (8%) cm yr-1 for E, 118±11 (9%) cm yr-1 for P, and 11±4 (36%) cm yr-1 for E-P, where the mean and error represent the ensemble mean and one standard deviation of the ensemble spread. The E-P uncertainty exceeds the uncertainty in E and P by a factor of four or more. The large uncertainty is attributed to P in the tropical wet zone. Most reanalyses tend to produce a wider tropical rain band when compared to satellite products, with the exception of two recent reanalyses that implement an observation-based correction for the model-generated P over land. The disparity in the width and the extent of seasonal migrations of the tropical wet zone causes large spread in P, implying that the tropical moist physics and the realism of tropical rainfall remain a key challenge. Satellite salinity appears feasible to evaluate the fidelity of E-P variability in three tropical areas, where the uncertainty diagnosis has a global indication

    Toxic effects of hexaflumuron on the development of Cocccinella septempunctata

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    Studying the toxic risk of pesticide exposure to ladybird beetles is important from an agronomical and ecological perspective since larval and adult ladybirds are dominant predators of herbivorous pest insects (e.g., aphids) in various crops in China. This article mainly deals with the long-term effects of a single application of the insect growth regulator hexaflumuron on Coccinella septempunctata. A 72- h and a 33-day toxicity test with hexaflumuron (single application) were performed, starting with the second instar larvae of C. septempunctata. Exposure doses in the long-term experiment were based on the estimated 72-h acute LR50 (application rate causing 50 % mortality) value of 304 g active ingredient (a.i.) ha-1 for second instar larvae of C. septempunctata. The long-term test used five hexaflumuron doses as treatment levels (1/50, 1/100, 1/200, 1/400, and 1/800 of the 72-h acute LR50), as well as a solvent control and blank control treatment. The measurement endpoints used to calculate no observed effect application rates (NOERs) included development time, hatching, pupation, adult emergence, survival, and number of eggs produced. Analyzing the experimental data with one-way analysis of variance showed that the single hexaflumuron application had significant effects on C. septempunctata endpoints in the 33-day test, including effects on development duration (NOER 1.52 g a.i. ha-1), hatching (NOER 3.04 g a.i. ha-1), pupation (NOER 3.04 g a.i. ha-1), and survival (NOER 1.52 g a.i. ha-1). These NOERs are lower than the reported maximum field application rate of hexaflumuron (135 g a.i. ha-1) in cotton cultivation, suggesting potential risks to beneficial arthropods

    Eff ect of a comprehensive programme to provide universal access to care for sputum-smear-positive multidrugresistant tuberculosis in China: a before-and-after study

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    Background China has a quarter of all patients with multidrug-resistant tuberculosis (MDRTB) worldwide, but less than 5% are in quality treatment programmes. In a before-and-after study we aimed to assess the eff ect of a comprehensive programme to provide universal access to diagnosis, treatment, and follow-up for MDRTB in four Chinese cities (population 18 million). Methods We designated city-level hospitals in each city to diagnose and treat MDRTB. All patients with smear-positive pulmonary tuberculosis diagnosed in Center for Disease Control (CDC) clinics and hospitals were tested for MDRTB with molecular and conventional drug susceptibility tests. Patients were treated with a 24 month treatment package for MDRTB based on WHO guidelines. Outpatients were referred to the CDC for directly observed therapy. We capped total treatment package cost at US4644.Insurancereimbursementandprojectsubsidieslimitedpatients’expensesto10(2011)tothosefromaretrospectivesurveyofallpatientswithMDRTBdiagnosedinthesamecitiesduringabaselineperiod(2006–09).Findings243patientswerediagnosedwithMDRTBorrifampicin−resistanttuberculosisduringthe12monthprogrammeperiodcomparedwith92patients(equivalentto24peryear)duringthebaselineperiod.172(71243individualswereenrolledintheprogramme.Timefromspecimencollectionforresistancetestingtotreatmentinitiationdecreasedby90startedonappropriatedrugregimenincreased2⋅7times(fromnine[35172),andfollow−upbytheCDCafterinitialhospitalisationincreased24times(fromone[4163[99increasedtentimes(fromtwo[8programmeperiodhadnegativeculturesorclinical–radiographicimprovement.Patients’expensesforhospitaladmissionafterMDRTBdiagnosisdecreasedby784644. Insurance reimbursement and project subsidies limited patients’ expenses to 10% of charges for services within the package. We compared data from a 12 month programme period (2011) to those from a retrospective survey of all patients with MDRTB diagnosed in the same cities during a baseline period (2006–09). Findings 243 patients were diagnosed with MDRTB or rifampicin-resistant tuberculosis during the 12 month programme period compared with 92 patients (equivalent to 24 per year) during the baseline period. 172 (71%) of 243 individuals were enrolled in the programme. Time from specimen collection for resistance testing to treatment initiation decreased by 90% (from median 139 days [IQR 69–207] to 14 days [10–21]), the proportion of patients who started on appropriate drug regimen increased 2·7 times (from nine [35%] of 26 patients treated to 166 [97%] of 172), and follow-up by the CDC after initial hospitalisation increased 24 times (from one [4%] of 23 patients to 163 [99%] of 164 patients). 6 months after starting treatment, the proportion of patients remaining on treatment increased ten times (from two [8%] of 26 patients to 137 [80%] of 172), and 116 (67%) of 172 patients in the programme period had negative cultures or clinical–radiographic improvement. Patients’ expenses for hospital admission after MDRTB diagnosis decreased by 78% (from 796 to $174), reducing the ratio of patients’ expenses to annual household income from 17·6% to 3·5% (p<0·0001 for all comparisons between baseline and programme periods). However, 36 (15%) patients did not start or had to discontinue treatment in the programme period because of fi nancial diffi culties. Interpretation This comprehensive programme substantially increased access to diagnosis, quality treatment, and aff ordable treatment for MDRTB. The programme could help China to achieve universal access to MDRTB care but greater fi nancial risk protection for patients is needed

    PSR J1926-0652: A Pulsar with Interesting Emission Properties Discovered at FAST

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    We describe PSR J1926-0652, a pulsar recently discovered with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). Using sensitive single-pulse detections from FAST and long-term timing observations from the Parkes 64-m radio telescope, we probed phenomena on both long and short time scales. The FAST observations covered a wide frequency range from 270 to 800 MHz, enabling individual pulses to be studied in detail. The pulsar exhibits at least four profile components, short-term nulling lasting from 4 to 450 pulses, complex subpulse drifting behaviours and intermittency on scales of tens of minutes. While the average band spacing P3 is relatively constant across different bursts and components, significant variations in the separation of adjacent bands are seen, especially near the beginning and end of a burst. Band shapes and slopes are quite variable, especially for the trailing components and for the shorter bursts. We show that for each burst the last detectable pulse prior to emission ceasing has different properties compared to other pulses. These complexities pose challenges for the classic carousel-type models.Comment: 13pages with 12 figure
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