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An alternative formulation of the Langley plot relating observed solar irradiance, extraterrestrial solar irradiance, and air mass has been suggested to potentially improve radiometer calibration accuracy. In this study, results from the traditional and alternative plotting methods are compared using both simulated and measured data. The simulations indicate that their relative accuracies depend on the time scale of the atmospheric extinction fluctuations. The two methods are found to be essentially equivalent with the measured data. [ABSTRACT FROM AUTHOR] more...

The estimation of ultraviolet-A (UV-A) radiation across the earth’s surface is needed to model plant productivity and future impacts of ultraviolet-B radiation on plant productivity. We have developed two models to estimate the UV-A irradiance from measurements of the diffuse and global spectral irradiance at 368 nm. The models were developed from 30-min-interval measurements made throughout 2000 at three locations across the United States and evaluated from 30-min measurements made throughout 2000 at three additional locations and throughout 2001 and 2002 at seven locations. UV-A irradiance was best estimated from measured global 368-nm irradiance and empirical functions defining the UV-A and 368-nm irradiance values estimated from a theoretical pseudospherical two-stream discrete-ordinates radiative transfer model. The radiative transfer model provided baseline irradiance relationships between UV-A irradiance and 368-nm spectral irradiance. The semiempirical model estimated the UV-A irradiance at seven locations across the United States with a mean bias error of 0.5 W m-2 and a root-mean-square error of 2 W m-2, corresponding to approximately ±4% of a clear-sky irradiance of 50 W m-2 for a solar zenith angle of 30°. This model error was comparable to the combined effect of previously estimated UV-A and 368-nm irradiance measurement errors. [ABSTRACT FROM AUTHOR] more...

Abstract: As a part of the Big Bend Regional Aerosol and Visibility Observational Study (BRAVO, July–October 1999), aerosol physical, optical and chemical properties were measured continuously in an effort to characterize visibility in Big Bend National Park. Surface-based estimates of aerosol extinction coefficients derived from size distribution data were compared to aerosol optical properties retrieved independently from ground-based remote sensing measurements from the United States Department of Agriculture (USDA) UVB radiometer network site. Comparisons suggested that for the majority of the study, surface visibility was a good indicator of the column aerosol optical depth, with a correlation coefficient of . The average (and one standard deviation) aerosol optical depth from the USDA network was 0.13±0.06 at a wavelength of 500nm. Ångstrom wavelength exponents were computed for both data sets to characterize the spectral variations of aerosol optical properties over the wavelength range of 415–860nm. Variations in Ångstrom exponents corresponded to changing aerosol properties as seen in the ground-based composition and size distribution data sets. The average Ångstrom exponent from in situ measurements was 1.5±0.4 compared to column estimates of 1.3±0.4. The root mean square of the difference between the estimates of Ångstrom exponents was 0.20 (∼12%) and on average the estimates were highly correlated (). Aerosol optical depths and ambient surface aerosol extinction coefficients were positively correlated with PM2.5 sulfate mass concentrations ( and , respectively), suggesting that sulfate aerosols were a major contributor to visibility degradation and column aerosol loading during the study. [Copyright &y& Elsevier] more...

Background Patients with active cancer are often on chronic anticoagulation and frequently require interruption of this treatment for invasive procedures. The impact of cancer on periprocedural thromboembolism (TE) and major bleeding is not known. Patients and methods Two thousand one hundred and eighty-two consecutive patients referred for periprocedural anticoagulation (2484 procedures) using a standardized protocol were followed forward in time to estimate the 3-month incidence of TE, major bleeding and survival stratified by anticoagulation indication. For each indication, we tested active cancer and bridging heparin therapy as potential predictors of TE and major bleeding. Results Compared with patients without cancer, active cancer patients (n = 493) had more venous thromboembolism (VTE) complications (1.2 % versus 0.2 % ; P = 0.001), major bleeding (3.4 % versus 1.7 % ; P = 0.02) and reduced survival (95 % versus 99 % ; P < 0.001). Among active cancer patients, only those chronically anticoagulated for VTE had higher rates of periprocedural VTE (2 % versus 0.16 % ; P = 0.002) and major bleeding (3.7 % versus 0.6 % ; P < 0.001). Bridging with heparin increased the rate of major bleeding in cancer patients (5 % versus 1 % ; P = 0.03) without impacting the VTE rate (0.7 % versus 1.4 % , P = 0.50). Conclusions Cancer patients anticoagulated for VTE experience higher rates of periprocedural VTE and major bleeding. Periprocedural anticoagulation for these patients requires particular attention to reduce these complications. [ABSTRACT FROM AUTHOR] more...

A pharmacogenetic study suggests the 5-HTT LPR polymorphism predicts response to alosetron, and another study describes a possible association of the GN β3 C825T polymorphism with IBS in patients with dyspepsia. We performed a case–control association study to determine whether these polymorphisms are associated with irritable bowel syndrome (IBS). The study aim was to compare allele and genotype frequencies between cases and controls for the 5-HTT LPR and the GN β3 C825T polymorphism. Cases were 50 GI outpatients; controls were 53 General Medicine outpatients matched to cases for age, gender and race at a major medical centre. Participants completed a questionnaire and donated blood. DNA was genotyped using polymerase chain reaction based assays. Eighty-two per cent of cases met Rome II criteria for IBS: 12% constipation-, 46% diarrhoea-, and 42% mixed-IBS. Genotype and allele frequencies for both polymorphisms did not differ between cases and controls. However, the allele frequency of the short (S) allele of the 5-HTT LPR polymorphism was greater in those with mixed-IBS compared with controls (68% vs 45%, P < 0.05). This study suggests that the 5-HTT LPR polymorphism may be associated with mixed-IBS, but not IBS overall. No association was observed for the GN β3 C825T polymorphism with IBS overall or subtypes. [ABSTRACT FROM AUTHOR] more...

Lung cancer is a major cause of death in the United States and other countries. The risk of lung cancer is greatly increased by cigarette smoking and by certain occupational exposures, but familial factors also clearly play a major role. To identify susceptibility genes for familial lung cancer, we conducted a genomewide linkage analysis of 52 extended pedigrees ascertained through probands with lung cancer who had several first-degree relatives with the same disease. Multipoint linkage analysis, under a simple autosomal dominant model, of all 52 families with three or more individuals affected by lung, throat, or laryngeal cancer, yielded a maximum heterogeneity LOD score (HLOD) of 2.79 at 155 cM on chromosome 6q (marker D652436). A subset of 38 pedigrees with four or more affected individuals yielded a multipoint HLOD of 347 at 155 cM. Analysis of a further subset of 23 multige- nerational pedigrees with five or more affected individuals yielded a multipoint HLOD score of 4.26 at the same position. The 14 families with only three affected relatives yielded negative LOD scores in this region. A predivided samples test for heterogeneity comparing the LOD scores from the 23 multigenerational families with those from the remaining families was significant (P = .007). The 1-HLOD multipoint support interval from the multigenerational families extends from C651848 at 146 cM to 164 cM near D651035, overlapping a genomic region that is deleted in sporadic lung cancers as well as numerous other cancer types. Parametric linkage and variance- components analysis that incorporated effects of age and personal smoking also supported linkage in this region, but with somewhat diminished support. These results localize a major susceptibility locus influencing lung cancer risk to 6q23-25. [ABSTRACT FROM AUTHOR] more...

The article presents abstracts on medical topics including a study to assess the mean platelet volume (MPV), periprocedural bleeding in chronically anticoagulated patients and efficacy of eliminating hyperpigmentation with the use of intense pulse light generator (IPL). more...