667 research outputs found

    Color Transformations for the 2MASS Second Incremental Data Release

    Get PDF
    Transformation equations are presented to convert colors and magnitudes measured in the AAO, ARNICA, CIT, DENIS, ESO, LCO (Persson standards), MSSSO, SAAO, and UKIRT photometric systems to the photometric system inherent to the 2MASS Second Incremental Data Release. The transformations have been derived by comparing 2MASS photometry with published magnitudes and colors for stars observed in these systems. Transformation equations have also been derived indirectly for the Bessell & Brett (1988) and Koornneef (1983) homogenized photometric systems.Comment: To appear in AJ, May 200

    Long-oligomer microarray profiling in Neurospora crassa reveals the transcriptional program underlying biochemical and physiological events of conidial germination

    Get PDF
    To test the inferences of spotted microarray technology against a biochemically well-studied process, we performed transcriptional profiling of conidial germination in the filamentous fungus, Neurospora crassa. We first constructed a 70 base oligomer microarray that assays 3366 predicted genes. To estimate the relative gene expression levels and changes in gene expression during conidial germination, we analyzed a circuit design of competitive hybridizations throughout a time course using a Bayesian analysis of gene expression level. Remarkable consistency of mRNA profiles with previously published northern data was observed. Genes were hierarchically clustered into groups with respect to their expression profiles over the time course of conidial germination. A functional classification database was employed to characterize the global picture of gene expression. Consensus motif searches identified a putative regulatory component associated with genes involved in ribosomal biogenesis. Our transcriptional profiling data correlate well with biochemical and physiological processes associated with conidial germination and will facilitate functional predictions of novel genes in N.crassa and other filamentous ascomycete species. Furthermore, our dataset on conidial germination allowed comparisons to transcriptional mechanisms associated with germination processes of diverse propagules, such as teliospores of the phytopathogenic fungus Ustilago maydis and spores of the social amoeba Dictyostelium discoideum

    Measuring Distances Using Infrared Surface Brightness Fluctuations

    Get PDF
    Surface brightness fluctuations (SBFs) are much brighter in the IR than they are at optical wavelengths, making it possible to measure greater distances using IR SBFs. We report new K' (2.1 micron) SBF measurements of 9 galaxies in the Fornax and Eridanus clusters using a 1024^2-pixel HgCdTe array. We used improved analysis techniques to remove contributions from globular clusters and background galaxies, and we assess the relative importance of other sources of residual variance. We applied the improved methodology to Fornax and Eridanus images and to previously published Virgo cluster data. Apparent fluctuation magnitudes were used in conjunction with Cepheid distances to M31 and the Virgo cluster to calibrate the K' SBF distance scale. We find the absolute fluctuation magnitude MK'= -5.61+/-0.12, with an intrinsic scatter to the calibration of 0.06 mag. No statistically significant change in MK' is detected as a function of (V-I). Our calibration is consistent with constant age and metallicity stellar population models. The lack of a correlation with (V-I) in the context of the stellar population models implies that elliptical galaxies bluer than (V-I)=1.2 have SBFs dominated by younger (5-8 Gyr) populations. K' SBFs prove to be a reliable distance indicator as long as the residual variance from globular clusters and background galaxies is properly removed. Also, it is important that a sufficiently high S/N ratio be achieved to allow reliable sky subtraction because residual spatial variance can bias the measurement of the SBF power spectrum. (abridged)Comment: Accepted for publication in ApJ, 44 pages, 10 Postscript figure

    The role of Comprehension in Requirements and Implications for Use Case Descriptions

    Get PDF
    Within requirements engineering it is generally accepted that in writing specifications (or indeed any requirements phase document), one attempts to produce an artefact which will be simple to comprehend for the user. That is, whether the document is intended for customers to validate requirements, or engineers to understand what the design must deliver, comprehension is an important goal for the author. Indeed, advice on producing ‘readable’ or ‘understandable’ documents is often included in courses on requirements engineering. However, few researchers, particularly within the software engineering domain, have attempted either to define or to understand the nature of comprehension and it’s implications for guidance on the production of quality requirements. Therefore, this paper examines thoroughly the nature of textual comprehension, drawing heavily from research in discourse process, and suggests some implications for requirements (and other) software documentation. In essence, we find that the guidance on writing requirements, often prevalent within software engineering, may be based upon assumptions which are an oversimplification of the nature of comprehension. Hence, the paper examines guidelines which have been proposed, in this case for use case descriptions, and the extent to which they agree with discourse process theory; before suggesting refinements to the guidelines which attempt to utilise lessons learned from our richer understanding of the underlying discourse process theory. For example, we suggest subtly different sets of writing guidelines for the different tasks of requirements, specification and design

    Adjunctive Glucocorticoid Therapy in Patients with Septic Shock.

    Get PDF
    Background Whether hydrocortisone reduces mortality among patients with septic shock is unclear. Methods We randomly assigned patients with septic shock who were undergoing mechanical ventilation to receive hydrocortisone (at a dose of 200 mg per day) or placebo for 7 days or until death or discharge from the intensive care unit (ICU), whichever came first. The primary outcome was death from any cause at 90 days. Results From March 2013 through April 2017, a total of 3800 patients underwent randomization. Status with respect to the primary outcome was ascertained in 3658 patients (1832 of whom had been assigned to the hydrocortisone group and 1826 to the placebo group). At 90 days, 511 patients (27.9%) in the hydrocortisone group and 526 (28.8%) in the placebo group had died (odds ratio, 0.95; 95% confidence interval [CI], 0.82 to 1.10; P=0.50). The effect of the trial regimen was similar in six prespecified subgroups. Patients who had been assigned to receive hydrocortisone had faster resolution of shock than those assigned to the placebo group (median duration, 3 days [interquartile range, 2 to 5] vs. 4 days [interquartile range, 2 to 9]; hazard ratio, 1.32; 95% CI, 1.23 to 1.41; P<0.001). Patients in the hydrocortisone group had a shorter duration of the initial episode of mechanical ventilation than those in the placebo group (median, 6 days [interquartile range, 3 to 18] vs. 7 days [interquartile range, 3 to 24]; hazard ratio, 1.13; 95% CI, 1.05 to 1.22; P<0.001), but taking into account episodes of recurrence of ventilation, there were no significant differences in the number of days alive and free from mechanical ventilation. Fewer patients in the hydrocortisone group than in the placebo group received a blood transfusion (37.0% vs. 41.7%; odds ratio, 0.82; 95% CI, 0.72 to 0.94; P=0.004). There were no significant between-group differences with respect to mortality at 28 days, the rate of recurrence of shock, the number of days alive and out of the ICU, the number of days alive and out of the hospital, the recurrence of mechanical ventilation, the rate of renal-replacement therapy, and the incidence of new-onset bacteremia or fungemia. Conclusions Among patients with septic shock undergoing mechanical ventilation, a continuous infusion of hydrocortisone did not result in lower 90-day mortality than placebo. (Funded by the National Health and Medical Research Council of Australia and others; ADRENAL ClinicalTrials.gov number, NCT01448109 .)

    Discovery of the first symbiotic star in NGC6822

    Full text link
    We report the discovery of the first symbiotic star (V=21.6, K_S=15.8 mag) in the Local Group dwarf irregular galaxy NGC6822. This star was identified during a spectral survey of Ha emission-line objects using the Southern African Large Telescope (SALT) during its performance-verification phase. The observed strong emission lines of HI and HeII suggest a high electron density and T* < 130 000 K for the hot companion. The infrared colours allow us to classify this object as an S-type symbiotic star, comprising a red giant losing mass to a compact companion. The red giant is an AGB carbon star, and a semi-regular variable, pulsating in the first overtone with a period of 142 days. Its bolometric magnitude is M_bol=-4.4 mag. We review what is known about the luminosities of extragalactic symbiotic stars, showing that most, possibly all, contain AGB stars. We suggest that a much larger fraction of Galactic symbiotic stars may contain AGB stars than was previously realised.Comment: 6 pages, 4 figures, accepted to MNRA

    B cell–adaptive immune profile in emphysema-predominant chronic obstructive pulmonary disease

    Get PDF
    Cigarette smoke, the major risk factor for COPD in developed countries, causes pulmonary inflammation that persists long after smoking cessation, suggesting self-perpetuating adaptive immune responses similar to those that occur in autoimmune diseases. Increases in the number and size of B cell–rich lymphoid follicles (LFs) have been shown in patients in severe stages of COPD (4), and increased B-cell products (autoantibodies) have been observed in the blood and lungs of patients with COPD (5, 6). Oligoclonal rearrangement of the immunoglobulin genes has been observed in B cells isolated from COPD LFs, suggesting that a specific antigenic stimulation drives B-cell proliferation. Consistently, we have shown that in the COPD lung, there is an overexpression of BAFF (B-cell activation factor of the TNF family), which is a key regulator of B-cell homeostasis in several autoimmune diseases (7) and is involved in the growth of LFs in COPD. However, a network analysis of lung transcriptomics showed that a prominent B-cell molecular signature characterized emphysema preferentially but was absent in AD independently of the degree of airflow limitation (8). In the current study, we investigated the correlation between B-cell responses in lung tissue from patients with COPD and healthy smokers, and the extent of emphysema versus airflow limitation

    Quantitative Trait Loci Associated with the Immune Response to a Bovine Respiratory Syncytial Virus Vaccine

    Get PDF
    Infectious disease is an important problem for animal breeders, farmers and governments worldwide. One approach to reducing disease is to breed for resistance. This linkage study used a Charolais-Holstein F2 cattle cross population (n = 501) which was genotyped for 165 microsatellite markers (covering all autosomes) to search for associations with phenotypes for Bovine Respiratory Syncytial Virus (BRSV) specific total-IgG, IgG1 and IgG2 concentrations at several time-points pre- and post-BRSV vaccination. Regions of the bovine genome which influenced the immune response induced by BRSV vaccination were identified, as well as regions associated with the clearance of maternally derived BRSV specific antibodies. Significant positive correlations were detected within traits across time, with negative correlations between the pre- and post-vaccination time points. The whole genome scan identified 27 Quantitative Trait Loci (QTL) on 13 autosomes. Many QTL were associated with the Thymus Helper 1 linked IgG2 response, especially at week 2 following vaccination. However the most significant QTL, which reached 5% genome-wide significance, was on BTA 17 for IgG1, also 2 weeks following vaccination. All animals had declining maternally derived BRSV specific antibodies prior to vaccination and the levels of BRSV specific antibody prior to vaccination were found to be under polygenic control with several QTL detected

    Household air pollution in low- and middle-income countries: health risks and research priorities

    Get PDF
    Household air pollution (HAP), which results from incomplete combustion of the solid fuels traditionally used for cooking and heating, affects the homes of nearly 3 billion people. It is the leading environmental cause of death and disability worldwide, with highest risks for women and children due to their domestic roles. The high levels of pollutants found in HAP cause a range of diseases, in addition to burns and scalds and injuries or violence experienced during fuel collection. Additionally, household solid fuel use can pose substantive environmental risks, including degradation from fuel gathering as well as climate change from release of both CO2 and short-lived climate forcers, such as black carbon, during combustion. Despite the broad support to find solutions, only a few solid fuel interventions have shown that they might improve health over the long term, especially when implemented at the scale required (Box 1)
    corecore