WorldWideScience

Sample records for sunlight individual cluster

  1. Sunlight Modulates Fruit Metabolic Profile and Shapes the Spatial Pattern of Compound Accumulation within the Grape Cluster

    Science.gov (United States)

    Reshef, Noam; Walbaum, Natasha; Agam, Nurit; Fait, Aaron

    2017-01-01

    Vineyards are characterized by their large spatial variability of solar irradiance (SI) and temperature, known to effectively modulate grape metabolism. To explore the role of sunlight in shaping fruit composition and cluster uniformity, we studied the spatial pattern of incoming irradiance, fruit temperature and metabolic profile within individual grape clusters under three levels of sunlight exposure. The experiment was conducted in a vineyard of Cabernet Sauvignon cv. located in the Negev Highlands, Israel, where excess SI and midday temperatures are known to degrade grape quality. Filtering SI lowered the surface temperature of exposed fruits and increased the uniformity of irradiance and temperature in the cluster zone. SI affected the overall levels and patterns of accumulation of sugars, organic acids, amino acids and phenylpropanoids, across the grape cluster. Increased exposure to sunlight was associated with lower accumulation levels of malate, aspartate, and maleate but with higher levels of valine, leucine, and serine, in addition to the stress-related proline and GABA. Flavan-3-ols metabolites showed a negative response to SI, whereas flavonols were highly induced. The overall levels of anthocyanins decreased with increased sunlight exposure; however, a hierarchical cluster analysis revealed that the members of this family were grouped into three distinct accumulation patterns, with malvidin anthocyanins and cyanidin-glucoside showing contrasting trends. The flavonol-glucosides, quercetin and kaempferol, exhibited a logarithmic response to SI, leading to improved cluster uniformity under high-light conditions. Comparing the within-cluster variability of metabolite accumulation highlighted the stability of sugars, flavan-3-ols, and cinnamic acid metabolites to SI, in contrast to the plasticity of flavonols. A correlation-based network analysis revealed that extended exposure to SI modified metabolic coordination, increasing the number of negative

  2. FINDCLUS : Fuzzy INdividual Differences CLUStering

    NARCIS (Netherlands)

    Giordani, Paolo; Kiers, Henk A. L.

    ADditive CLUStering (ADCLUS) is a tool for overlapping clustering of two-way proximity matrices (objects x objects). In Simple Additive Fuzzy Clustering (SAFC), a variant of ADCLUS is introduced providing a fuzzy partition of the objects, that is the objects belong to the clusters with the so-called

  3. Roadmaps for powering the world, U.S., and individual states for all purposes with wind, water, and sunlight (Invited)

    Science.gov (United States)

    Jacobson, M. Z.

    2013-12-01

    Global warming, air pollution, and energy insecurity are three of the most significant problems facing the world today. This talk discusses these problems and technical and economic plans to solve them by powering 100% of the world, individual countries, and states for all purposes, including electricity, transportation, industry, and heating/cooling, with wind, water, and sunlight (WWS) together with efficiency measures, within 20-40 years. Specific plans for New York State and California are discussed. For California, the plan contemplates all new energy powered with WWS by 2020, 80-85% of existing energy replaced by 2030, and 100% replaced by 2050. Electrification plus modest efficiency measures would reduce California's end-use power demand ~44% and stabilize energy prices since WWS fuel costs are zero. Even without additional efficiency improvements, remaining all-purpose 2030 end-use demand could be met with 25% onshore and 10% offshore wind, 15% concentrated solar, 15% utility-scale PV, 10% residential PV, 15% commercial/government PV, 5% geothermal, 0.5% wave, 0.5% tidal, and 4% hydroelectric. These percentages will shift upon implementation. Converting would create ~137,000 net permanent jobs, decrease ~16,000 (4,800-29,600) state air pollution deaths/yr, and avoid 131 (39-296) billion/yr in health costs (6.9% of California's 2010 gross domestic product), repaying the 1 trillion capital cost for 573 GW installed power within ~7.3 yr. California's emission decreases would reduce 2050 U.S. and global climate costs by ~6 and 60 billion/yr, respectively.

  4. Taxicab tipping and sunlight

    Science.gov (United States)

    2017-01-01

    Does the level of sunlight affect the tipping percentage in taxicab rides in New York City? We examined this question using data on 13.82 million cab rides from January to October in 2009 in New York City combined with data on hourly levels of solar radiation. We found a small but statistically significant positive relationship between sunlight and tipping, with an estimated tipping increase of 0.5 to 0.7 percentage points when transitioning from a dark sky to full sunshine. The findings are robust to two-way clustering of standard errors based on hour-of-the-day and day-of-the-year and controlling for day-of-the-year, month-of-the-year, cab driver fixed effects, weather conditions, and ride characteristics. The NYC cab ride context is suitable for testing the association between sunlight and tipping due to the largely random assignment of riders to drivers, direct exposure to sunlight, and low confounding from variation in service experiences. PMID:28594917

  5. Individualization as driving force of clustering phenomena in humans.

    Directory of Open Access Journals (Sweden)

    Michael Mäs

    Full Text Available One of the most intriguing dynamics in biological systems is the emergence of clustering, in the sense that individuals self-organize into separate agglomerations in physical or behavioral space. Several theories have been developed to explain clustering in, for instance, multi-cellular organisms, ant colonies, bee hives, flocks of birds, schools of fish, and animal herds. A persistent puzzle, however, is the clustering of opinions in human populations, particularly when opinions vary continuously, such as the degree to which citizens are in favor of or against a vaccination program. Existing continuous opinion formation models predict "monoculture" in the long run, unless subsets of the population are perfectly separated from each other. Yet, social diversity is a robust empirical phenomenon, although perfect separation is hardly possible in an increasingly connected world. Considering randomness has not overcome the theoretical shortcomings so far. Small perturbations of individual opinions trigger social influence cascades that inevitably lead to monoculture, while larger noise disrupts opinion clusters and results in rampant individualism without any social structure. Our solution to the puzzle builds on recent empirical research, combining the integrative tendencies of social influence with the disintegrative effects of individualization. A key element of the new computational model is an adaptive kind of noise. We conduct computer simulation experiments demonstrating that with this kind of noise a third phase besides individualism and monoculture becomes possible, characterized by the formation of metastable clusters with diversity between and consensus within clusters. When clusters are small, individualization tendencies are too weak to prohibit a fusion of clusters. When clusters grow too large, however, individualization increases in strength, which promotes their splitting. In summary, the new model can explain cultural clustering in

  6. Experiments on individual alumina-supported adatoms and clusters

    Science.gov (United States)

    Nilius, N.; Cörper, A.; Bozdech, G.; Ernst, N.; Freund, H.-J.

    2001-08-01

    To contribute to an understanding of growth conditions and electronic properties of metal clusters on technologically relevant oxides we have examined the mobility of individual, alumina-supported Pt-adatoms and the optical properties of single supported Ag-clusters. Using field-ion microscopy (FIM) we have prepared and imaged an individual Pt-adatom at approximately 40 K, both on the apex plane of a [1 1 0]-oriented NiAl tip and on a thin alumina film, grown on the same NiAl specimen by oxidation. On the alumina film, the onset temperature for Pt surface diffusion approaches 100 K being distinctively lower than the value 165 K measured on NiAl(1 1 0). Employing the tip of a scanning tunneling microscope (STM) as a local electron source, photon emission from individual, alumina-supported Ag-clusters was spectroscopically analyzed. The occurrence of a distinct emission line is explained by the decay of a collective electron oscillation (Mie-plasmon resonance). For decreasing Ag-cluster diameter, the emission lines (i) shift to higher energies and (ii) their widths increase. To explain these observations, we discuss (i) the reduced screening of the plasmon oscillation due to the Ag 4d electrons and (ii) an enhanced electron surface scattering rate in small clusters.

  7. Individualization as driving force of clustering phenomena in humans

    CERN Document Server

    Mäs, Michael; Helbing, Dirk

    2010-01-01

    One of the most intriguing dynamics in biological systems is the emergence of clustering, the self-organization into separated agglomerations of individuals. Several theories have been developed to explain clustering in, for instance, multi-cellular organisms, ant colonies, bee hives, flocks of birds, schools of fish, and animal herds. A persistent puzzle, however, is clustering of opinions in human populations. The puzzle is particularly pressing if opinions vary continuously, such as the degree to which citizens are in favor of or against a vaccination program. Existing opinion formation models suggest that "monoculture" is unavoidable in the long run, unless subsets of the population are perfectly separated from each other. Yet, social diversity is a robust empirical phenomenon, although perfect separation is hardly possible in an increasingly connected world. Considering randomness did not overcome the theoretical shortcomings so far. Small perturbations of individual opinions trigger social influence cas...

  8. Partially mixed household epidemiological model with clustered resistant individuals.

    Science.gov (United States)

    Hiebeler, David E; Criner, Amanda Keck

    2007-02-01

    We study the dynamics of the spread of an infectious disease within a population partitioned into households, and stratified into resistant and nonresistant individuals. Variability in the level of resistance between households increases the initial rate of spread of the infection, as well as the infection level at the endemic equilibrium. This phenomenon is seen even when all individuals in the population are equally likely to be resistant, and can also be predicted by including spatial clustering of resistant individuals within an improved mean-field approximation.

  9. Sunlight exposure behaviour and vitamin D status in photosensitive patients: longitudinal comparative study with healthy individuals at U.K. latitude.

    Science.gov (United States)

    Rhodes, L E; Webb, A R; Berry, J L; Felton, S J; Marjanovic, E J; Wilkinson, J D; Vail, A; Kift, R

    2014-12-01

    Low vitamin D status is prevalent in wintertime in populations at northerly latitudes. Photosensitive patients are advised to practise sun avoidance, but their sunlight exposure levels, photoprotective measures and resulting vitamin D status are unknown. To examine seasonal vitamin D status in photosensitive patients relative to healthy individuals and to assess quantitatively behavioural and demographic contributors. This was a longitudinal prospective cohort study (53·5°N) examining year-round 25-hydroxyvitamin D [25(OH)D] levels, sun-exposure behaviour and oral vitamin D intake in photosensitive patients diagnosed at a photoinvestigation unit (n = 53), compared with concurrently assessed healthy adults (n = 109). Photosensitive patients achieved seasonal 25(OH)D variation, but insufficient (exposure (P = 0·004) and greater sunscreen use (P exposure predicted summer peak and winter trough 25(OH)D levels. A 1 μg per day increment in supplementary vitamin D raised summer and winter 25(OH)D by 5% (95% CI 3-7) and 9% (95% CI 5-12), respectively (both P < 0·001). Photosensitive patients are, through their photoprotective measures, at high risk of year-round low vitamin D status. Guidance on oral measures should target this patient group and their physicians. © 2014 British Association of Dermatologists.

  10. Supplementing vitamin D through sunlight: associating health literacy with sunlight exposure behavior.

    Science.gov (United States)

    Leung, Angela Yee Man; Cheung, Mike Kwun Ting; Chi, Iris

    2015-01-01

    To test whether health literacy is associated with sunlight exposure behavior, we interviewed 648 Chinese adults aged 65 years or older. Using the information-motivation-behavioral skills model and structural equation modeling, we tested whether health literacy was associated with the complex relationships among knowledge about vitamin D, attitudes toward sunlight exposure, doctor recommendations regarding sunlight exposure, and sunlight exposure behavior. Health literacy was directly associated with sunlight exposure (β=.20, psunlight exposure through health literacy (β=.46, psunlight exposure through health literacy (β=-.12, psunlight exposure. Providing relevant knowledge or making doctor recommendations might not be effective. Training should focus on individuals with low health literacy who may be less likely to receive sunlight exposure. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  11. Optical imaging of individual biomolecules in densely packed clusters

    Science.gov (United States)

    Dai, Mingjie; Jungmann, Ralf; Yin, Peng

    2016-09-01

    Recent advances in fluorescence super-resolution microscopy have allowed subcellular features and synthetic nanostructures down to 10-20 nm in size to be imaged. However, the direct optical observation of individual molecular targets (∼5 nm) in a densely packed biomolecular cluster remains a challenge. Here, we show that such discrete molecular imaging is possible using DNA-PAINT (points accumulation for imaging in nanoscale topography)—a super-resolution fluorescence microscopy technique that exploits programmable transient oligonucleotide hybridization—on synthetic DNA nanostructures. We examined the effects of a high photon count, high blinking statistics and an appropriate blinking duty cycle on imaging quality, and developed a software-based drift correction method that achieves optical nanodisplay with 5 × 5 nm pixel size and three distinct colours with <1 nm cross-channel registration accuracy.

  12. Optical visualisation of individual biomolecules in densely packed clusters

    Science.gov (United States)

    Dai, Mingjie; Jungmann, Ralf; Yin, Peng

    2016-01-01

    Recent advances in fluorescence super-resolution microscopy have allowed sub-cellular features and synthetic nanostructures down to ~15 nm in size to be imaged. However, direct optical observation of individual molecular targets (~5 nm) in a densely packed biomolecular cluster remains a challenge. Here, we show that such discrete molecular imaging is possible using DNA-PAINT (points accumulation for imaging in nanoscale topography) - a super-resolution fluorescence microscopy technique that exploits programmable transient oligonucleotide hybridisation - on synthetic DNA nanostructures. We examined the effects of high photon count, high blinking statistics, and appropriate blinking duty cycle on imaging quality, and developed a software-based drift correction method that achieves origami structural offset with angstrom-level precision (2 Å) from single-molecule studies. By combining the approach with multiplexed Exchange-PAINT imaging, we further demonstrated an optical nano-display with 5×5 nm pixel size and three distinct colours, and with <1 nm cross-channel registration accuracy. This method opens up possibilities for direct and quantitative optical observation of individual biomolecular features in crowded environments. PMID:27376244

  13. Effects of sunlight exposure on grapevine powdery mildew development.

    Science.gov (United States)

    Austin, Craig N; Wilcox, Wayne F

    2012-09-01

    Natural and artificially induced shade increased grapevine powdery mildew (Erysiphe necator) severity in the vineyard, with foliar disease severity 49 to 75% higher relative to leaves in full sun, depending on the level of natural shading experienced and the individual experiment. Cluster disease severities increased by 20 to 40% relative to those on check vines when ultraviolet (UV) radiation was filtered from sunlight reaching vines in artificial shading experiments. Surface temperatures of leaves in full sunlight averaged 5 to 8°C higher than those in natural shade, and in one experiment, filtering 80% of all wavelengths of solar radiation, including longer wavelengths responsible for heating irradiated tissues, increased disease more than filtering UV alone. In controlled environment experiments, UV-B radiation reduced germination of E. necator conidia and inhibited both colony establishment (hyphal formation and elongation) and maturity (latent period). Inhibitory effects of UV-B radiation were significantly greater at 30°C than at 20 or 25°C. Thus, sunlight appears to inhibit powdery mildew development through at least two mechanisms, i.e., (i) UV radiation's damaging effects on exposed conidia and thalli of the pathogen; and (ii) elevating temperatures of irradiated tissues to a level supraoptimal or inhibitory for pathogen development. Furthermore, these effects are synergistic at temperatures near the upper threshold for disease development.

  14. Identifying Two Groups of Entitled Individuals: Cluster Analysis Reveals Emotional Stability and Self-Esteem Distinction.

    Science.gov (United States)

    Crowe, Michael L; LoPilato, Alexander C; Campbell, W Keith; Miller, Joshua D

    2016-12-01

    The present study hypothesized that there exist two distinct groups of entitled individuals: grandiose-entitled, and vulnerable-entitled. Self-report scores of entitlement were collected for 916 individuals using an online platform. Model-based cluster analyses were conducted on the individuals with scores one standard deviation above mean (n = 159) using the five-factor model dimensions as clustering variables. The results support the existence of two groups of entitled individuals categorized as emotionally stable and emotionally vulnerable. The emotionally stable cluster reported emotional stability, high self-esteem, more positive affect, and antisocial behavior. The emotionally vulnerable cluster reported low self-esteem and high levels of neuroticism, disinhibition, conventionality, psychopathy, negative affect, childhood abuse, intrusive parenting, and attachment difficulties. Compared to the control group, both clusters reported being more antagonistic, extraverted, Machiavellian, and narcissistic. These results suggest important differences are missed when simply examining the linear relationships between entitlement and various aspects of its nomological network.

  15. Initial Development of a Measure of Emotional Dysregulation for Individuals with Cluster B Personality Disorders

    Science.gov (United States)

    Newhill, Christina E.; Mulvey, Edward P.; Pilkonis, Paul A.

    2004-01-01

    Individuals with DSM-IV Cluster B personality disorders are at particular risk of violence toward self or others. Emotional dysregulation is likely to be a factor in such incidents and is a central issue addressed in therapies with personality-disordered individuals. This article reports findings from a study that developed an original 18-item…

  16. Sunlight and Vitamin D

    Science.gov (United States)

    Wacker, Matthias; Holick, Michael F.

    2013-01-01

    Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years. During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3. Previtamin D3 and vitamin D3 also absorb UV B radiation and are converted into a variety of photoproducts some of which have unique biologic properties. Sun induced vitamin D synthesis is greatly influenced by season, time of day, latitude, altitude, air pollution, skin pigmentation, sunscreen use, passing through glass and plastic, and aging. Vitamin D is metabolized sequentially in the liver and kidneys into 25-hydroxyvitamin D which is a major circulating form and 1,25-dihydroxyvitamin D which is the biologically active form respectively. 1,25-dihydroxyvitamin D plays an important role in regulating calcium and phosphate metabolism for maintenance of metabolic functions and for skeletal health. Most cells and organs in the body have a vitamin D receptor and many cells and organs are able to produce 1,25-dihydroxyvitamin D. As a result 1,25-dihydroxyvitamin D influences a large number of biologic pathways which may help explain association studies relating vitamin D deficiency and living at higher latitudes with increased risk for many chronic diseases including autoimmune diseases, some cancers, cardiovascular disease, infectious disease, schizophrenia and type 2 diabetes. A three-part strategy of increasing food fortification programs with vitamin D, sensible sun exposure recommendations and encouraging ingestion of a vitamin D supplement when needed should be implemented to prevent global vitamin D deficiency and its negative health consequences. PMID:24494042

  17. Genetic factors influence the clustering of depression among individuals with lower socioeconomic status

    NARCIS (Netherlands)

    S. López León (Sandra); W.C. Choy (Wing Chi); Y.S. Aulchenko (Yurii); S. Claes (Stephan); B.A. Oostra (Ben); J.P. Mackenbach (Johan); C.M. van Duijn (Cock); A.C.J.W. Janssens (Cécile)

    2009-01-01

    textabstractObjective: To investigate the extent to which shared genetic factors can explain the clustering of depression among individuals with lower socioeconomic status, and to examine if neuroticism or intelligence are involved in these pathways. Methods: In total 2,383 participants (1,028 men a

  18. Identifying influential individuals on intensive care units: using cluster analysis to explore culture.

    Science.gov (United States)

    Fong, Allan; Clark, Lindsey; Cheng, Tianyi; Franklin, Ella; Fernandez, Nicole; Ratwani, Raj; Parker, Sarah Henrickson

    2017-07-01

    The objective of this paper is to identify attribute patterns of influential individuals in intensive care units using unsupervised cluster analysis. Despite the acknowledgement that culture of an organisation is critical to improving patient safety, specific methods to shift culture have not been explicitly identified. A social network analysis survey was conducted and an unsupervised cluster analysis was used. A total of 100 surveys were gathered. Unsupervised cluster analysis was used to group individuals with similar dimensions highlighting three general genres of influencers: well-rounded, knowledge and relational. Culture is created locally by individual influencers. Cluster analysis is an effective way to identify common characteristics among members of an intensive care unit team that are noted as highly influential by their peers. To change culture, identifying and then integrating the influencers in intervention development and dissemination may create more sustainable and effective culture change. Additional studies are ongoing to test the effectiveness of utilising these influencers to disseminate patient safety interventions. This study offers an approach that can be helpful in both identifying and understanding influential team members and may be an important aspect of developing methods to change organisational culture. © 2017 John Wiley & Sons Ltd.

  19. Sunlight-induced DNA damage in human mononuclear cells

    DEFF Research Database (Denmark)

    Møller, Peter; Wallin, Hakan; Holst, Erik

    2002-01-01

    of sunlight was comparable to the interindividual variation, indicating that sunlight exposure and the individual's background were the two most important determinants for the basal level of DNA damage. Influence of other lifestyle factors such as exercise, intake of foods, infections, and age could......In this study of 301 blood samples from 21 subjects, we found markedly higher levels of DNA damage (nonpyrimidine dimer types) in the summer than in the winter detected by single-cell gel electrophoresis. The level of DNA damage was influenced by the average daily influx of sunlight ... to blood sampling. The 3 and 6 day periods before sampling influenced DNA damage the most. The importance of sunlight was further emphasized by a positive association of the DNA damage level to the amount of time the subjects had spent in the sun over a 3 day period prior to the sampling. The effect...

  20. Searching for IMBHs in Galactic globular clusters through radial velocities of individual stars

    Science.gov (United States)

    Lanzoni, Barbara

    2016-02-01

    I present an overview of our ongoing project aimed at building a new generation of velocity dispersion profiles ad rotation curves for a representative sample of Galactic globular clusters, from the the radial velocity of hundreds of individual stars distributed at different distances from the cluster center. The innermost portion of the profiles will be used to constrain the possible presence of intermediate-mass black holes. The adopted methodology consists of combining spectroscopic observations acquired with three different instruments at the ESO-VLT: the adaptive-optics assisted, integral field unit (IFU) spectrograph SINFONI for the innermost and highly crowded cluster cores, the multi-IFU spectrograph KMOS for the intermediate regions, and the multi-fiber instrument FLAMES/GIRAFFE-MEDUSA for the outskirts. The case of NGC 6388, representing the pilot project that motivated the entire program, is described in some details.

  1. Individual predisposition, household clustering and risk factors for human infection with Ascaris lumbricoides: new epidemiological insights.

    Directory of Open Access Journals (Sweden)

    Martin Walker

    Full Text Available BACKGROUND: Much of our current understanding of the epidemiology of Ascaris lumbricoides infections in humans has been acquired by analyzing worm count data. These data are collected by treating infected individuals with anthelmintics so that worms are expelled intact from the gastrointestinal tract. Analysis of such data established that individuals are predisposed to infection with few or many worms and members of the same household tend to harbor similar numbers of worms. These effects, known respectively as individual predisposition and household clustering, are considered characteristic of the epidemiology of ascariasis. The mechanisms behind these phenomena, however, remain unclear. In particular, the impact of heterogeneous individual exposures to infectious stages has not been thoroughly explored. METHODOLOGY/PRINCIPAL FINDINGS: Bayesian methods were used to fit a three-level hierarchical statistical model to A. lumbricoides worm counts derived from a three-round chemo-expulsion study carried out in Dhaka, Bangladesh. The effects of individual predisposition, household clustering and household covariates of the numbers of worms per host (worm burden were considered simultaneously. Individual predisposition was found to be of limited epidemiological significance once household clustering had been accounted for. The degree of intra-household variability among worm burdens was found to be reduced by approximately 58% when household covariates were included in the model. Covariates relating to decreased affluence and quality of housing construction were associated with a statistically significant increase in worm burden. CONCLUSIONS/SIGNIFICANCE: Heterogeneities in the exposure of individuals to infectious eggs have an important role in the epidemiology of A. lumbricoides infection. The household covariates identified as being associated with worm burden provide valuable insights into the source of these heterogeneities although above all

  2. Shoreline resilience to individual storms and storm clusters on a meso-macrotidal barred beach

    Science.gov (United States)

    Angnuureng, Donatus Bapentire; Almar, Rafael; Senechal, Nadia; Castelle, Bruno; Addo, Kwasi Appeaning; Marieu, Vincent; Ranasinghe, Roshanka

    2017-08-01

    This study investigates the impact of individual storms and storm clusters on shoreline recovery for the meso-to macrotidal, barred Biscarrosse beach in SW France, using 6 years of daily video observations. While the study area experienced 60 storms during the 6-year study period, only 36 storms were analysed due to gaps in the video data. Based on the 36 individual storms and 13 storm clusters analysed, our results show that clustering impact is cumulatively weak and shoreline retreat is governed by the first storms in clusters, while the impact of subsequent events is less pronounced. The average post-storm beach recovery period at this site is 9 days, consistent with observations at other beaches. Apart from the dominant effect of present storm conditions, shoreline dynamics are also significantly affected by previous storm influence, while recovery is strongly modulated by tidal range and the bar location. Our results reveal that not only is the storm energy important but also the frequency of recurrence (storms result in greater retreat when time intervals between them are longer), which suggests an interaction between short storm events and longer-term evolution.

  3. Advanced Electrochemistry of Individual Metal Clusters Electrodeposited Atom by Atom to Nanometer by Nanometer.

    Science.gov (United States)

    Kim, Jiyeon; Dick, Jeffrey E; Bard, Allen J

    2016-11-15

    Metal clusters are very important as building blocks for nanoparticles (NPs) for electrocatalysis and electroanalysis in both fundamental and applied electrochemistry. Attention has been given to understanding of traditional nucleation and growth of metal clusters and to their catalytic activities for various electrochemical applications in energy harvesting as well as analytical sensing. Importantly, understanding the properties of these clusters, primarily the relationship between catalysis and morphology, is required to optimize catalytic function. This has been difficult due to the heterogeneities in the size, shape, and surface properties. Thus, methods that address these issues are necessary to begin understanding the reactivity of individual catalytic centers as opposed to ensemble measurements, where the effect of size and morphology on the catalysis is averaged out in the measurement. This Account introduces our advanced electrochemical approaches to focus on each isolated metal cluster, where we electrochemically fabricated clusters or NPs atom by atom to nanometer by nanometer and explored their electrochemistry for their kinetic and catalytic behavior. Such approaches expand the dimensions of analysis, to include the electrochemistry of (1) a discrete atomic cluster, (2) solely a single NP, or (3) individual NPs in the ensemble sample. Specifically, we studied the electrocatalysis of atomic metal clusters as a nascent electrocatalyst via direct electrodeposition on carbon ultramicroelectrode (C UME) in a femtomolar metal ion precursor. In addition, we developed tunneling ultramicroelectrodes (TUMEs) to study electron transfer (ET) kinetics of a redox probe at a single metal NP electrodeposited on this TUME. Owing to the small dimension of a NP as an active area of a TUME, extremely high mass transfer conditions yielded a remarkably high standard ET rate constant, k(0), of 36 cm/s for outer-sphere ET reaction. Most recently, we advanced nanoscale

  4. Individual organisms as units of analysis: Bayesian-clustering alternatives in population genetics.

    Science.gov (United States)

    Mank, Judith E; Avise, John C

    2004-12-01

    Population genetic analyses traditionally focus on the frequencies of alleles or genotypes in 'populations' that are delimited a priori. However, there are potential drawbacks of amalgamating genetic data into such composite attributes of assemblages of specimens: genetic information on individual specimens is lost or submerged as an inherent part of the analysis. A potential also exists for circular reasoning when a population's initial identification and subsequent genetic characterization are coupled. In principle, these problems are circumvented by some newer methods of population identification and individual assignment based on statistical clustering of specimen genotypes. Here we evaluate a recent method in this genre--Bayesian clustering--using four genotypic data sets involving different types of molecular markers in non-model organisms from nature. As expected, measures of population genetic structure (F(ST) and phiST) tended to be significantly greater in Bayesian a posteriori data treatments than in analyses where populations were delimited a priori. In the four biological contexts examined, which involved both geographic population structures and hybrid zones, Bayesian clustering was able to recover differentiated populations, and Bayesian assignments were able to identify likely population sources of specific individuals.

  5. A Two-Step Clustering Approach to Extract Locations from Individual GPS Trajectory Data

    Directory of Open Access Journals (Sweden)

    Zhongliang Fu

    2016-09-01

    Full Text Available High-accuracy location identification is the basis of location awareness and location services. However, because of the influence of GPS signal loss, data drift and repeated access in the individual trajectory data, the efficiency and accuracy of existing algorithms have some deficiencies. Therefore, we propose a two-step clustering approach to extract individuals’ locations according to their GPS trajectory data. Firstly, we defined three different types of stop points; secondly, we extracted these points from the trajectory data by using the spatio-temporal clustering algorithm based on time and distance. The experimental results show that the spatio-temporal clustering algorithm outperformed traditional extraction algorithms. It can avoid the problems caused by repeated access and can substantially reduce the effects of GPS signal loss and data drift. Finally, an improved clustering algorithm based on a fast search and identification of density peaks was applied to discover the trajectory locations. Compared to the existing algorithms, our method shows better performance and accuracy.

  6. A novel strategy for clustering major depression individuals using whole-genome sequencing variant data

    Science.gov (United States)

    Yu, Chenglong; Baune, Bernhard T.; Licinio, Julio; Wong, Ma-Li

    2017-01-01

    Major depressive disorder (MDD) is highly prevalent, resulting in an exceedingly high disease burden. The identification of generic risk factors could lead to advance prevention and therapeutics. Current approaches examine genotyping data to identify specific variations between cases and controls. Compared to genotyping, whole-genome sequencing (WGS) allows for the detection of private mutations. In this proof-of-concept study, we establish a conceptually novel computational approach that clusters subjects based on the entirety of their WGS. Those clusters predicted MDD diagnosis. This strategy yielded encouraging results, showing that depressed Mexican-American participants were grouped closer; in contrast ethnically-matched controls grouped away from MDD patients. This implies that within the same ancestry, the WGS data of an individual can be used to check whether this individual is within or closer to MDD subjects or to controls. We propose a novel strategy to apply WGS data to clinical medicine by facilitating diagnosis through genetic clustering. Further studies utilising our method should examine larger WGS datasets on other ethnical groups. PMID:28287625

  7. Clustered coding variants in the glutamate receptor complexes of individuals with schizophrenia and bipolar disorder.

    Science.gov (United States)

    Frank, René A W; McRae, Allan F; Pocklington, Andrew J; van de Lagemaat, Louie N; Navarro, Pau; Croning, Mike D R; Komiyama, Noboru H; Bradley, Sophie J; Challiss, R A John; Armstrong, J Douglas; Finn, Robert D; Malloy, Mary P; MacLean, Alan W; Harris, Sarah E; Starr, John M; Bhaskar, Sanjeev S; Howard, Eleanor K; Hunt, Sarah E; Coffey, Alison J; Ranganath, Venkatesh; Deloukas, Panos; Rogers, Jane; Muir, Walter J; Deary, Ian J; Blackwood, Douglas H; Visscher, Peter M; Grant, Seth G N

    2011-04-29

    Current models of schizophrenia and bipolar disorder implicate multiple genes, however their biological relationships remain elusive. To test the genetic role of glutamate receptors and their interacting scaffold proteins, the exons of ten glutamatergic 'hub' genes in 1304 individuals were re-sequenced in case and control samples. No significant difference in the overall number of non-synonymous single nucleotide polymorphisms (nsSNPs) was observed between cases and controls. However, cluster analysis of nsSNPs identified two exons encoding the cysteine-rich domain and first transmembrane helix of GRM1 as a risk locus with five mutations highly enriched within these domains. A new splice variant lacking the transmembrane GPCR domain of GRM1 was discovered in the human brain and the GRM1 mutation cluster could perturb the regulation of this variant. The predicted effect on individuals harbouring multiple mutations distributed in their ten hub genes was also examined. Diseased individuals possessed an increased load of deleteriousness from multiple concurrent rare and common coding variants. Together, these data suggest a disease model in which the interplay of compound genetic coding variants, distributed among glutamate receptors and their interacting proteins, contribute to the pathogenesis of schizophrenia and bipolar disorders.

  8. Clustered coding variants in the glutamate receptor complexes of individuals with schizophrenia and bipolar disorder.

    Directory of Open Access Journals (Sweden)

    René A W Frank

    Full Text Available Current models of schizophrenia and bipolar disorder implicate multiple genes, however their biological relationships remain elusive. To test the genetic role of glutamate receptors and their interacting scaffold proteins, the exons of ten glutamatergic 'hub' genes in 1304 individuals were re-sequenced in case and control samples. No significant difference in the overall number of non-synonymous single nucleotide polymorphisms (nsSNPs was observed between cases and controls. However, cluster analysis of nsSNPs identified two exons encoding the cysteine-rich domain and first transmembrane helix of GRM1 as a risk locus with five mutations highly enriched within these domains. A new splice variant lacking the transmembrane GPCR domain of GRM1 was discovered in the human brain and the GRM1 mutation cluster could perturb the regulation of this variant. The predicted effect on individuals harbouring multiple mutations distributed in their ten hub genes was also examined. Diseased individuals possessed an increased load of deleteriousness from multiple concurrent rare and common coding variants. Together, these data suggest a disease model in which the interplay of compound genetic coding variants, distributed among glutamate receptors and their interacting proteins, contribute to the pathogenesis of schizophrenia and bipolar disorders.

  9. Sunlight Responsive Thermochromic Window System

    Energy Technology Data Exchange (ETDEWEB)

    Millett, F,A; Byker,H, J

    2006-10-27

    Pleotint has embarked on a novel approach with our Sunlight Responsive Thermochromic, SRT™, windows. We are integrating dynamic sunlight control, high insulation values and low solar heat gain together in a high performance window. The Pleotint SRT window is dynamic because it reversibly changes light transmission based on thermochromics activated directly by the heating effect of sunlight. We can achieve a window package with low solar heat gain coefficient (SHGC), a low U value and high insulation. At the same time our windows provide good daylighting. Our innovative window design offers architects and building designers the opportunity to choose their desired energy performance, excellent sound reduction, external pane can be self-cleaning, or a resistance to wind load, blasts, bullets or hurricanes. SRT windows would provide energy savings that are estimated at up to 30% over traditional window systems. Glass fabricators will be able to use existing equipment to make the SRT window while adding value and flexibility to the basic design. Glazing installers will have the ability to fit the windows with traditional methods without wires, power supplies and controllers. SRT windows can be retrofit into existing buildings,

  10. Stability of Bacillus thuringiensis and NPV Microencapsulated Formulation under Sunlight

    Directory of Open Access Journals (Sweden)

    Samaneh Sadat Naghavi

    2016-06-01

    Full Text Available Microencapsulation technology is used for the formulation of bio pesticides and is effective against the ultra-violet radiation of sunlight. The present research studied the stability of Bt and NPV formulations microencapsulated with gelatin and sodium alginate, individually or in combination. The formulations were evaluated in outdoor space and under sunlight on potted growing cabbage. The stability of each active ingredient tested in each formulation was studied at 0, 3, 7 and 10 days after spraying on cabbage infested with diamondback moth Plutella xylostella second instars larvae. Results showed that non-formulated and microencapsulated formulations not exposed to sunlight (time zero had similar mortality. However, after being exposed to sunlight for three days, the non-formulated Bt and NPV resulted in a significantly lower mortality (less than 40%; compared with the microencapsulated bio pesticides (more than 70% mortality. Fifty percent (50% mortality was reached in microencapsulated formulations after seven and ten days of exposure to sunlight, whereas there was no mortality in larvae exposed to unformulated treated plants after ten days. ANOVA analysis showed the highest larval mortality was achieved by the Bt+NPV gelatin microencapsulated formulation followed by gelatin coated Bt, sodium alginate coated NPV, sodium alginate coated Bt+NPV, gelatin coated NPV and sodium alginate coated Bt. The formulations showed no significant LT50 differences between microencapsulated versus unformulated Bt and NPV.

  11. Recommendations for the analysis of individually randomised controlled trials with clustering in one arm – a case of continuous outcomes

    Directory of Open Access Journals (Sweden)

    Laura Flight

    2016-11-01

    Full Text Available Abstract Background In an individually randomised controlled trial where the treatment is delivered by a health professional it seems likely that the effectiveness of the treatment, independent of any treatment effect, could depend on the skill, training or even enthusiasm of the health professional delivering it. This may then lead to a potential clustering of the outcomes for patients treated by the same health professional, but similar clustering may not occur in the control arm. Using four case studies, we aim to provide practical guidance and recommendations for the analysis of trials with some element of clustering in one arm. Methods Five approaches to the analysis of outcomes from an individually randomised controlled trial with clustering in one arm are identified in the literature. Some of these methods are applied to four case studies of completed randomised controlled trials with clustering in one arm with sample sizes ranging from 56 to 539. Results are obtained using the statistical packages R and Stata and summarised using a forest plot. Results The intra-cluster correlation coefficient (ICC for each of the case studies was small (<0.05 indicating little dependence on the outcomes related to cluster allocations. All models fitted produced similar results, including the simplest approach of ignoring clustering for the case studies considered. Conclusions A partially clustered approach, modelling the clustering in just one arm, most accurately represents the trial design and provides valid results. Modelling homogeneous variances between the clustered and unclustered arm is adequate in scenarios similar to the case studies considered. We recommend treating each participant in the unclustered arm as a single cluster. This approach is simple to implement in R and Stata and is recommended for the analysis of trials with clustering in one arm only. However, the case studies considered had small ICC values, limiting the generalisability

  12. Exploring the individual patterns of spiritual well-being in people newly diagnosed with advanced cancer: a cluster analysis.

    Science.gov (United States)

    Bai, Mei; Dixon, Jane; Williams, Anna-Leila; Jeon, Sangchoon; Lazenby, Mark; McCorkle, Ruth

    2016-11-01

    Research shows that spiritual well-being correlates positively with quality of life (QOL) for people with cancer, whereas contradictory findings are frequently reported with respect to the differentiated associations between dimensions of spiritual well-being, namely peace, meaning and faith, and QOL. This study aimed to examine individual patterns of spiritual well-being among patients newly diagnosed with advanced cancer. Cluster analysis was based on the twelve items of the 12-item Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Scale at Time 1. A combination of hierarchical and k-means (non-hierarchical) clustering methods was employed to jointly determine the number of clusters. Self-rated health, depressive symptoms, peace, meaning and faith, and overall QOL were compared at Time 1 and Time 2. Hierarchical and k-means clustering methods both suggested four clusters. Comparison of the four clusters supported statistically significant and clinically meaningful differences in QOL outcomes among clusters while revealing contrasting relations of faith with QOL. Cluster 1, Cluster 3, and Cluster 4 represented high, medium, and low levels of overall QOL, respectively, with correspondingly high, medium, and low levels of peace, meaning, and faith. Cluster 2 was distinguished from other clusters by its medium levels of overall QOL, peace, and meaning and low level of faith. This study provides empirical support for individual difference in response to a newly diagnosed cancer and brings into focus conceptual and methodological challenges associated with the measure of spiritual well-being, which may partly contribute to the attenuated relation between faith and QOL.

  13. "Quantized" Doping of Individual Colloidal Nanocrystals Using Size-Focused Metal Quantum Clusters.

    Science.gov (United States)

    Santiago-González, Beatriz; Monguzzi, Angelo; Pinchetti, Valerio; Casu, Alberto; Prato, Mirko; Lorenzi, Roberto; Campione, Marcello; Chiodini, Norberto; Santambrogio, Carlo; Meinardi, Francesco; Manna, Liberato; Brovelli, Sergio

    2017-06-27

    The insertion of intentional impurities, commonly referred to as doping, into colloidal semiconductor quantum dots (QDs) is a powerful paradigm for tailoring their electronic, optical, and magnetic behaviors beyond what is obtained with size-control and heterostructuring motifs. Advancements in colloidal chemistry have led to nearly atomic precision of the doping level in both lightly and heavily doped QDs. The doping strategies currently available, however, operate at the ensemble level, resulting in a Poisson distribution of impurities across the QD population. To date, the synthesis of monodisperse ensembles of QDs individually doped with an identical number of impurity atoms is still an open challenge, and its achievement would enable the realization of advanced QD devices, such as optically/electrically controlled magnetic memories and intragap state transistors and solar cells, that rely on the precise tuning of the impurity states (i.e., number of unpaired spins, energy and width of impurity levels) within the QD host. The only approach reported to date relies on QD seeding with organometallic precursors that are intrinsically unstable and strongly affected by chemical or environmental degradation, which prevents the concept from reaching its full potential and makes the method unsuitable for aqueous synthesis routes. Here, we overcome these issues by demonstrating a doping strategy that bridges two traditionally orthogonal nanostructured material systems, namely, QDs and metal quantum clusters composed of a "magic number" of atoms held together by stable metal-to-metal bonds. Specifically, we use clusters composed of four copper atoms (Cu4) capped with d-penicillamine to seed the growth of CdS QDs in water at room temperature. The elemental analysis, performed by electrospray ionization mass spectrometry, X-ray fluorescence, and inductively coupled plasma mass spectrometry, side by side with optical spectroscopy and transmission electron microscopy

  14. Multigeneration reproduction ratios and the effects of clustered unvaccinated individuals on epidemic outbreak.

    Science.gov (United States)

    Hiebeler, David E; Michaud, Isaac J; Ackerman, Hamilton Hoxie; Reed Iosevich, Shannon; Robinson, Andre

    2011-12-01

    An SIR epidemiological community-structured model is constructed to investigate the effects of clustered distributions of unvaccinated individuals and the distribution of the primary case relative to vaccination levels. The communities here represent groups such as neighborhoods within a city or cities within a region. The model contains two levels of mixing, where individuals make more intra-group than inter-group contacts. Stochastic simulations and analytical results are utilized to explore the model. An extension of the effective reproduction ratio that incorporates more spatial information by predicting the average number of tertiary infections caused by a single infected individual is introduced to characterize the system. Using these methods, we show that both the vaccination coverage and the variation in vaccination levels among communities affect the likelihood and severity of epidemics. The location of the primary infectious case and the degree of mixing between communities are also important factors in determining the dynamics of outbreaks. In some cases, increasing the efficacy of a vaccine can in fact increase the effective reproduction ratio in early generations, due to the effects of population structure on the likely initial location of an infection.

  15. Template-assisted self-assembly of individual and clusters of magnetic nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Badini Confalonieri, G A; Ebbing, A; Mishra, D; Szary, P; Petracic, O; Zabel, H [Ruhr-Universitaet Bochum, Institut fuer Experimentalphysik/Festkoerperphysik, Bochum 44780 (Germany); Vega, V; Prida, V M, E-mail: giovanni.badini@rub.de [Departamento de Fisica, Universidad de Oviedo, Calvo Sotelo s/n, E-33007 Oviedo (Spain)

    2011-07-15

    The deliberate control over the spatial arrangement of nanostructures is the desired goal for many applications such as, for example, in data storage, plasmonics or sensor arrays. Here we present a novel method to assist the self-assembly process of magnetic nanoparticles. The method makes use of nanostructured aluminum templates obtained after anodization of aluminum discs and the subsequent growth and removal of the newly formed alumina layer, resulting in a regular honeycomb-type array of hexagonally shaped valleys. The iron oxide nanoparticles, 20 nm in diameter, are spin-coated onto the surface of honeycomb nanostructured Al templates. Depending on the size, each hexagon site can host up to 30 nanoparticles. These nanoparticles form clusters of different arrangements within the valleys, such as collars, chains and hexagonally closed islands. Ultimately, it is possible to isolate individual nanoparticles. The strengths of the magnetic interaction between particles in a cluster are probed using the memory effect known from the coupled state in superspin glass systems.

  16. The symptom cluster-based approach to individualize patient-centered treatment for major depression.

    Science.gov (United States)

    Lin, Steven Y; Stevens, Michael B

    2014-01-01

    Unipolar major depressive disorder is a common, disabling, and costly disease that is the leading cause of ill health, early death, and suicide in the United States. Primary care doctors, in particular family physicians, are the first responders in this silent epidemic. Although more than a dozen different antidepressants in 7 distinct classes are widely used to treat depression in primary care, there is no evidence that one drug is superior to another. Comparative effectiveness studies have produced mixed results, and no specialty organization has published recommendations on how to choose antidepressants in a rational, evidence-based manner. In this article we present the theory and evidence for an individualized, patient-centered treatment model for major depression designed around a targeted symptom cluster-based approach to antidepressant selection. When using this model for healthy adults with major depressive disorder, the choice of antidepressants should be guided by the presence of 1 of 4 common symptom clusters: anxiety, fatigue, insomnia, and pain. This model was built to foster future research, provide a logical framework for teaching residents how to select antidepressants, and equip primary care doctors with a structured treatment strategy to deliver optimal patient-centered care in the management of a debilitating disease: major depressive disorder.

  17. Sunlight exposure: Do health benefits outweigh harm?

    Science.gov (United States)

    Razzaque, Mohammed S

    2016-09-16

    Vitamin D is a fat-soluble vitamin whose levels within the body are elevated following sunlight exposure. Numerous studies have shown that sunlight exposure can provide protection to a wide variety of diseases, ranging from different types of tumors to hypertension to type 1 diabetes to multiple sclerosis. Moreover, studies have shown that avoiding sunlight may influence the initiation and progression of some of these diseases. Avoidance of sunlight, coupled with the inclination towards consuming supplements, is becoming the primary choice to obtain vitamin D. The purpose of this article is to present evidences from published literature, to show that the expected benefits of vitamin D supplements are minimized by the potential risk of cardiovascular events and beyond. Since hypovitaminosis D status usually reflects reduced sunlight exposure, the obvious primary replacement should be safe sunlight exposure, and not exogenous supplements. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Identifying and Tracking Individual Updraft Cores using Cluster Analysis: A TWP-ICE case study

    Science.gov (United States)

    Li, X.; Tao, W.; Collis, S. M.; Varble, A.

    2013-12-01

    Cumulus parameterizations in GCMs depend strongly on the vertical velocity structures of convective updraft cores, or plumes. There hasn't been an accurate way of identifying these cores. The majority of previous studies treat the updraft as a single grid column entity, thus missing many intrinsic characteristics, e.g., the size, strength and spatial orientation of an individual core, its life cycle, and the time variations of the entrainment/detrainment rates associated with its life cycle. In this study, we attempt to apply an innovative algorithm based on the centroid-based k-means cluster analysis to improve our understanding of convection and its associated updraft cores. Both 3-D Doppler radar retrievals and cloud-resolving model simulations of a TWP-ICE campaign case during the monsoon period will be used to test and improve this algorithm. This will provide for more in-depth comparisons between CRM simulations and observations that were not possible previously using the traditional piecewise analysis with each updraft column. The first step is to identify the strongest cores (maximum velocity >10 m/s), since they are well defined and produce definite answers when the cluster analysis algorithm is applied. The preliminary results show that the radar retrieved updraft cores are smaller in size and with the maximum velocity located uniformly at higher levels compared with model simulations. Overall, the model simulations produce much stronger cores compared with the radar retrievals. Within the model simulations, the bulk microphysical scheme simulation produces stronger cores than the spectral bin microphysical scheme. Planned researches include using high temporal-resolution simulations to further track the life cycle of individual updraft cores and study their characteristics.

  19. Sunlight exposure, antioxidants, and age-related macular degeneration.

    Science.gov (United States)

    Fletcher, Astrid E; Bentham, Graham C; Agnew, Maureen; Young, Ian S; Augood, Cristina; Chakravarthy, Usha; de Jong, Paulus T V M; Rahu, Mati; Seland, Johan; Soubrane, Gisele; Tomazzoli, Laura; Topouzis, Fotis; Vingerling, Johannes R; Vioque, Jesus

    2008-10-01

    To examine the association of sunlight exposure and antioxidant level with age-related macular degeneration (AMD). Four thousand seven hundred fifty-three participants aged 65 years or older in the European Eye Study underwent fundus photography, were interviewed for adult lifetime sunlight exposure, and gave blood for antioxidant analysis. Blue light exposure was estimated by combining meteorologic and questionnaire data. Data on sunlight exposure and antioxidants were available in 101 individuals with neovascular AMD, 2182 with early AMD, and 2117 controls. No association was found between blue light exposure and neovascular or early AMD. Significant associations were found between blue light exposure and neovascular AMD in individuals in the quartile of lowest antioxidant level-vitamin C, zeaxanthin, vitamin E, and dietary zinc-with an odds ratio of about 1.4 for 1 standard deviation unit increase in blue light exposure. Higher odds ratios for blue light were observed with combined low antioxidant levels, especially vitamin C, zeaxanthin, and vitamin E (odds ratio, 3.7; 95% confidence interval, 1.6-8.9), which were also associated with early stages of AMD. Although it is not possible to establish causality between sunlight exposure and neovascular AMD, our results suggest that people in the general population should use ocular protection and follow dietary recommendations for the key antioxidant nutrients.

  20. Analysis of individual- and school-level clustering of power frequency magnetic fields.

    Science.gov (United States)

    Lin, I-Fan; Li, Chung-Yi; Wang, Jung-Der

    2008-10-01

    This study reports the continuous 8-h monitoring of data on extremely low-frequency magnetic fields (ELF-MF) relating to 14 children and 35 teachers in 11 elementary schools in Northern Taiwan. It was anticipated that the subjects in two of these campuses would have elevated exposure to ELF-MF as a result of their close proximity to high-voltage (161 kilo-Volt, kV) power lines. The results of our analysis reveal that in those schools with high-voltage power lines running through the campuses, the mean ELF-MF exposure level (0.38 +/- 0.51 micro-Tesla (microT), or 0.15, 0.25 and 0.44 microT at the respective 25th, 50th and 75th percentiles) was higher than the mean ELF-MF exposure level for campuses situated far away from such high-voltage power lines (0.14 +/- 0.27 microT, or 0.04, 0.06 and 0.10 microT at the respective 25th, 50th and 75th percentiles). The multi-level analytical technique, which takes individual measurements as the analytical unit, and which also takes into consideration the inter-correlation between measurements from the same individual and/or campus, was also applied to the analysis of the data. We conclude that individual-level and school-level clustering of the measurements, both of which were discernible in this study, should be taken into consideration in any future analysis of data obtained from the continuous monitoring of exposure to ELF-MF.

  1. T-cell triggering thresholds are modulated by the number of antigen within individual T-cell receptor clusters

    Energy Technology Data Exchange (ETDEWEB)

    Manz, Boryana N. [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Univ. of California, Berkeley, CA (United States); Jackson, Bryan L. [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Petit, Rebecca S. [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Dustin, Michael L. [New York School of Medicine, New York, NY (United States); Groves, Jay [Howard Hughes Medical Inst., Chevy Chase, MD (United States); Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

    2011-05-31

    T cells react to extremely small numbers of activating agonist peptides. Spatial organization of T-cell receptors (TCR) and their peptide-major histocompatibility complex (pMHC) ligands into microclusters is correlated with T-cell activation. In this study, we have designed an experimental strategy that enables control over the number of agonist peptides per TCR cluster, without altering the total number engaged by the cell. Supported membranes, partitioned with grids of barriers to lateral mobility, provide an effective way of limiting the total number of pMHC ligands that may be assembled within a single TCR cluster. Observations directly reveal that restriction of pMHC content within individual TCR clusters can decrease T-cell sensitivity for triggering initial calcium flux at fixed total pMHC density. Further analysis suggests that triggering thresholds are determined by the number of activating ligands available to individual TCR clusters, not by the total number encountered by the cell. Results from a series of experiments in which the overall agonist density and the maximum number of agonist per TCR cluster are independently varied in primary T cells indicate that the most probable minimal triggering unit for calcium signaling is at least four pMHC in a single cluster for this system. In conclusion, this threshold is unchanged by inclusion of coagonist pMHC, but costimulation of CD28 by CD80 can modulate the threshold lower.

  2. Multi-state models for clustered duration data: an application to workplace effects on individual sickness absenteeism

    OpenAIRE

    Lindeboom, M.; Kerkhofs, M.

    1998-01-01

    In this paper we specify and estimate three state duration models of work, sickness and exit from the job to explain individual absenteeism behaviour of primary school teachers. There is a large variation of sickness absenteeism records across schools and absenteeism records of workers within a school appear to be related. This clustering of individual absenteeism data may to a large extend be caused by workplace effects. Since it will be difficult to fully capture workplace effects with obse...

  3. Technique to separate lidar signal and sunlight.

    Science.gov (United States)

    Sun, Wenbo; Hu, Yongxiang; MacDonnell, David G; Weimer, Carl; Baize, Rosemary R

    2016-06-13

    Sunlight contamination dominates the backscatter noise in space-based lidar measurements during daytime. The background scattered sunlight is highly variable and dependent upon the surface and atmospheric albedo. The scattered sunlight contribution to noise increases over land and snow surfaces where surface albedos are high and thus overwhelm lidar backscatter from optically thin atmospheric constituents like aerosols and thin clouds. In this work, we developed a novel lidar remote sensing concept that potentially can eliminate sunlight induced noise. The new lidar concept requires: (1) a transmitted laser light that carries orbital angular momentum (OAM); and (2) a photon sieve (PS) diffractive filter that separates scattered sunlight from laser light backscattered from the atmosphere, ocean and solid surfaces. The method is based on numerical modeling of the focusing of Laguerre-Gaussian (LG) laser beam and plane-wave light by a PS. The model results show that after passing through a PS, laser light that carries the OAM is focused on a ring (called "focal ring" here) on the focal plane of the PS filter, very little energy arrives at the center of the focal plane. However, scattered sunlight, as a plane wave without the OAM, focuses at the center of the focal plane and thus can be effectively blocked or ducted out. We also find that the radius of the "focal ring" increases with the increase of azimuthal mode (L) of LG laser light, thus increasing L can more effectively separate the lidar signal away from the sunlight noise.

  4. Effects of concentrated sunlight on organic photovoltaics

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Katz, Eugene A.; Hirsch, Baruch

    2010-01-01

    gradually from 0.2 to 27 suns. Power conversion efficiency exhibited slow increase with C that was followed by saturation around 2% at C = 0.5–2.5 suns and subsequent strong reduction. Possible OPV applications in stationary solar concentrators (C ≤ 2 suns) are discussed. Finally, experiments at C = 55......We report the effects of concentrated sunlight on key photovoltaic parameters and stability of organic photovoltaics (OPV). Sunlight collected and concentrated outdoors was focused into an optical fiber and delivered onto a 1 cm2 bulk-heterojunction cell. Sunlight concentration C was varied...

  5. Quantitative analysis of individual hepatocyte growth factor receptor clusters in influenza A virus infected human epithelial cells using localization microscopy.

    Science.gov (United States)

    Wang, Qiaoyun; Dierkes, Rüdiger; Kaufmann, Rainer; Cremer, Christoph

    2014-04-01

    In this report, we applied a special localization microscopy technique (Spectral Precision Distance/Spatial Position Determination Microscopy/SPDM) to quantitatively analyze the effect of influenza A virus (IAV) infection on the spatial distribution of individual HGFR (Hepatocyte Growth Factor Receptor) proteins on the membrane of human epithelial cells at the single molecule resolution level. We applied this SPDM method to Alexa 488 labeled HGFR proteins with two different ligands. The ligands were either HGF (Hepatocyte Growth Factor), or IAV. In addition, the HGFR distribution in a control group of mock-incubated cells without any ligands was investigated. The spatial distribution of 1×10(6) individual HGFR proteins localized in large regions of interest on membranes of 240 cells was quantitatively analyzed and found to be highly non-random. Between 21% and 24% of the HGFR molecules were located in 44,304 small clusters with an average diameter of 54nm. The mean density of HGFR molecule signals per individual cluster was very similar in control cells, in cells with ligand only, and in IAV infected cells, independent of the incubation time. From the density of HGFR molecule signals in the clusters and the diameter of the clusters, the number of HGFR molecule signals per cluster was estimated to be in the range between 4 and 11 (means 5-6). This suggests that the membrane bound HGFR clusters form small molecular complexes with a maximum diameter of few tens of nm, composed of a relatively low number of HGFR molecules. This article is part of a Special Issue entitled: Viral Membrane Proteins - Channels for Cellular Networking. Copyright © 2013 Elsevier B.V. All rights reserved.

  6. Can Natural Sunlight Induce Coherent Exciton Dynamics?

    CERN Document Server

    Olšina, Jan; Wang, Chen; Cao, Jianshu

    2014-01-01

    Excitation of a model photosynthetic molecular aggregate by incoherent sunlight is systematically examined. For a closed system, the excited state coherence induced by the sunlight oscillates with an average amplitude that is inversely proportional to the excitonic gap, and reaches a stationary amplitude that depends on the temperature and coherence time of the radiation field. For an open system, the light-induced dynamical coherence relaxes to a static coherence determined by the non-canonical thermal distribution resulting from the entanglement with the phonon bath. The decay of the excited state population to the common ground state establishes a non-equilibrium steady-state flux driven by the sunlight, and it defines a time window to observe the transition from dynamical to static coherence. For the parameters relevant to photosynthetic systems, the exciton dynamics initiated by the sunlight exhibits a non-negligible amount of dynamical coherence (quantum beats) on the sub-picosecond timescale; however, ...

  7. Study of Neurocognitive correlates of Schizotypy Personality Clusters in healthy individuals

    Directory of Open Access Journals (Sweden)

    M. Carmen Aguilera Ruíz

    2008-03-01

    Full Text Available Background and Objectives: Inconsistencies in the relationship between schizotypy dimensions and neurocognitive functions found in correlational studies may be clarified with the use of alternative methodological approaches. The aim of this study was to examine the existence of different profiles of schizotypal traits and their neurocognitIve correlates in non-clinical subjects by means of cluster analysis. Methods: We examined seventy six healthy adults from the general population with a comprehensive neurocognitive battery and a schizotypal personality self-report. Results: Four neurocognitive factors were extracted: visuospatial, semantic evocation, verbal memory, and set-shifting. A three cluster model yielded the following clusters: "lowschizotypy", "positive schizotypy", and "negative/disorganized schizotypy". The positive and negative/disorganized schizotypy clusters showed poorer performance on semantic evocation compared with the low schizotypy cluster. Conclusions: We found different patterns of specific schizotypy features in a healthy adult community sample and these clusters presented differential performance in relation with the ability to evoke semantic information.

  8. Analyzing the Role of Community and Individual Factors in Food Insecurity: Identifying Diverse Barriers Across Clustered Community Members.

    Science.gov (United States)

    Jablonski, Becca B R; McFadden, Dawn Thilmany; Colpaart, Ashley

    2016-10-01

    This paper uses the results from a community food security assessment survey of 684 residents and three focus groups in Pueblo County, Colorado to examine the question: what community and individual factors contribute to or alleviate food insecurity, and are these factors consistent throughout a sub-county population. Importantly, we use a technique called cluster analysis to endogenously determine the key factors pertinent to food access and fruit and vegetable consumption. Our results show significant heterogeneity among sub-population clusters in terms of the community and individual factors that would make it easier to get access to fruits and vegetables. We find two distinct clusters of food insecure populations: the first was significantly less likely to identify increased access to fruits and vegetables proximate to where they live or work as a way to improve their household's healthy food consumption despite being significantly less likely to utilize a personal vehicle to get to the store; the second group did not report significant challenges with access, rather with affordability. We conclude that though interventions focused on improving the local food retail environment may be important for some subsamples of the food insecure population, it is unclear that proximity to a store with healthy food will support enhanced food security for all. We recommend that future research recognizes that determinants of food insecurity may vary within county or zip code level regions, and that multiple interventions that target sub-population clusters may elicit better improvements in access to and consumption of fruits and vegetables.

  9. Clustering of individuals given SNPs similarity based on normalized mutual information: F7 SNPs in the GAIT sample.

    Science.gov (United States)

    Perera, Alexandre; Buil, Alfonso; Di Bernardo, Maria Chiara; Sabater-Lleal, Maria; Pattini, Linda; Souto, Juan Carlos; Fontcuberta, Jordi; Vallverdu, Montserrat; Soria, Jose Manuel; Caminal, Pere

    2007-01-01

    This paper proposes the clustering of individuals given their genotype using a normalized Mutual Information dissimilarity distance. This method is applied to a Single Nucleotyde Polymorphism set belonging to F7 gene, uncovering the intrinsic genetic variability on one Spanish population. This genetic variability corresponds to results published using a complete different approach in population genetics literature. Identified groups are shown to express significant differences in the level of FVII concentration.

  10. Ultra-accelerated natural sunlight exposure testing

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.J.; Bingham, C.; Goggin, R.; Lewandowski, A.A.; Netter, J.C.

    2000-06-13

    Process and apparatus are disclosed for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: (a) concentrating solar flux uniformly; (b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  11. Ultra-accelerated natural sunlight exposure testing

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, Gary J. (Pine, CO); Bingham, Carl (Lakewood, CO); Goggin, Rita (Englewood, CO); Lewandowski, Allan A. (Evergreen, CO); Netter, Judy C. (Westminster, CO)

    2000-06-13

    Process and apparatus for providing ultra accelerated natural sunlight exposure testing of samples under controlled weathering without introducing unrealistic failure mechanisms in exposed materials and without breaking reciprocity relationships between flux exposure levels and cumulative dose that includes multiple concurrent levels of temperature and relative humidity at high levels of natural sunlight comprising: a) concentrating solar flux uniformly; b) directing the controlled uniform sunlight onto sample materials in a chamber enclosing multiple concurrent levels of temperature and relative humidity to allow the sample materials to be subjected to accelerated irradiance exposure factors for a sufficient period of time in days to provide a corresponding time of about at least a years worth of representative weathering of the sample materials.

  12. Sunlight-Induced Coloration of Silk

    Science.gov (United States)

    Yao, Ya; Tang, Bin; Chen, Wu; Sun, Lu; Wang, Xungai

    2016-06-01

    Silk fabrics were colored by gold nanoparticles (NPs) that were in situ synthesized through the induction of sunlight. Owing to the localized surface plasmon resonance (LSPR) of gold NPs, the treated silk fabrics presented vivid colors. The photo-induced synthesis of gold NPs was also realized on wet silk through adsorbing gold ions out of solution, which provides a water-saving coloration method for textiles. Besides, the patterning of silk was feasible using this simple sunlight-induced coloration approach. The key factors of coloration including gold ion concentration, pH value, and irradiation time were investigated. Moreover, it was demonstrated that either ultraviolet (UV) light or visible light could induce the generation of gold NPs on silk fabrics. The silk fabrics with gold NPs exhibited high light resistance including great UV-blocking property and excellent fastness to sunlight.

  13. Degadation of semiconducting polymers by concentrated sunlight

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Manceau, Matthieu; Petersen, Martin Helgesen

    2011-01-01

    A lens based sunlight concentration setup was used to accelerate the degradation of semiconducting polymers. Sunlight was collected outdoor and focused into an optical fiber bundle allowing for indoor experimental work. Photo-degradation of several polymers was studied by UV–vis absorbance...... spectroscopy and infra-red spectroscopy. This showed that the degradation rate is significantly increased by increasing illumination intensity. Acceleration factors exceeding 100 compared to standard 1 sun illumination were observed for solar concentration of 200 suns in the case of P3HT. A comparison between...

  14. Sunlight Diffusing Tent for Lunar Worksite

    Science.gov (United States)

    Burleson, Blair; Clark, Todd; Deese, Todd; Gentry, Ernest; Samad, Abdul

    1990-01-01

    The purpose is to provide a solution to problems astronauts encounter with sunlight on the lunar surface. Due to the absence of an atmosphere the Moon is subjected to intense sunlight creating problems with color and contrast. This problem can be overcome by providing a way to reduce intensity and diffuse the light in a working environment. The solution to the problem utilizes an umbrella, tent-like structure covered with a diffusing material. The design takes into account structural materials, stresses, fabrics, and deployment.

  15. Estimating the Standard Error of the Impact Estimator in Individually Randomized Trials with Clustering

    Science.gov (United States)

    Weiss, Michael J.; Lockwood, J. R.; McCaffrey, Daniel F.

    2016-01-01

    In the "individually randomized group treatment" (IRGT) experimental design, individuals are first randomly assigned to a treatment arm or a control arm, but then within each arm, are grouped together (e.g., within classrooms/schools, through shared case managers, in group therapy sessions, through shared doctors, etc.) to receive…

  16. Water balance of goats in Jeneponto - South Sulawesi under sunlight exposure and water restriction

    Directory of Open Access Journals (Sweden)

    Djoni Prawira Rahardja

    2007-10-01

    Full Text Available Water balance of 5 does of Kacang goat of Jeneponto was studied under the condition of sunlight exposure and water restriction. The study was conducted in dry season with 4 consecutive treatments of 10 d with 4-5 d of adjustment period between two consecutive treatments: (1 indoor and unrestricted water; (2 indoor and restricted water; (3 10 h outdoor–and unrestricted water; (4 10 h outdoor – restricted water. The maximum air temperature of outdoor was 39.3OC, and it was 30OC in the indoor environment. In all treatments, the animals were placed in the individual crates. The plasma volume of the goats was higher under sunlight exposure, but it decreased by water restriction, while hematocrite value indicated a reverse responses. Sunlight exposure did not significantly decrease the intake and digestion of organic matter, but water restriction affected significantly and this effect was higher under sunlight exposre. The proportions of water loss through every avenue were maintained relatively constant either under water restriction or sunlight exposure in which the respration rate increased significantly. The findings suggest that sunlight exposure with unrestricted water resulted in a positive water balance without a significant change in organic matter intake and utilization. Water restriction resulted in a negative water balance, reducing organic matter intake and utilization. As the adaptive mechanisms, the goat appeared to be able to withstand in the harsh environment of Jeneponto by expanding plasma volume, increasing body temperature and respiration rate.

  17. Photochemical Transformation of Graphene Oxide in Sunlight

    Science.gov (United States)

    Graphene oxide (GO) is a graphene derivative that is more easily manufactured in large scale and used to synthesize reduced graphene oxide (rGO) with properties analogous to graphene. In this study, we investigate the photochemical fate of GO under sunlight conditions. The resu...

  18. Clustering of minor psychiatric disorders and burden among family caregivers of individuals with mental illness

    Directory of Open Access Journals (Sweden)

    Carlos Alberto dos Santos Treichel

    2016-02-01

    Full Text Available Abstract The objective of this cross-sectional study is to analyze the relationship between minor psychiatric disorders, burden and other associated factors among family caregivers of people with mental disorders. The study was conducted with 1164 relatives of users of the Centers for Psychosocial Care in southern Brazil, and for screening of minor psychiatric disorders, the Self-Reporting Questionnaire (SRQ20 scale was used, based on its Brazilian validation with an adopted cutoff point of 6/8. Even though previous studies have appointed the burden arising from care as protagonist in the presentation of minor psychiatric disorders, a clustering based on log-likelihood by Bayesian Information Criterion conducted in this study found that burden is not the only possible predictor for emotional/mental illness, suggesting that other factors permeate this relationship. Thus, bivariate analyzes were conducted, in which the influence of variables such as health problems, work issues, among others, can be observed in different groups arranged by the cluster.

  19. Individual Movement Strategies Revealed through Novel Clustering of Emergent Movement Patterns

    Science.gov (United States)

    Valle, Denis; Cvetojevic, Sreten; Robertson, Ellen P.; Reichert, Brian E.; Hochmair, Hartwig H.; Fletcher, Robert J.

    2017-03-01

    Understanding movement is critical in several disciplines but analysis methods often neglect key information by adopting each location as sampling unit, rather than each individual. We introduce a novel statistical method that, by focusing on individuals, enables better identification of temporal dynamics of connectivity, traits of individuals that explain emergent movement patterns, and sites that play a critical role in connecting subpopulations. We apply this method to two examples that span movement networks that vary considerably in size and questions: movements of an endangered raptor, the snail kite (Rostrhamus sociabilis plumbeus), and human movement in Florida inferred from Twitter. For snail kites, our method reveals substantial differences in movement strategies for different bird cohorts and temporal changes in connectivity driven by the invasion of an exotic food resource, illustrating the challenge of identifying critical connectivity sites for conservation in the presence of global change. For human movement, our method is able to reliably determine the origin of Florida visitors and identify distinct movement patterns within Florida for visitors from different places, providing near real-time information on the spatial and temporal patterns of tourists. These results emphasize the need to integrate individual variation to generate new insights when modeling movement data.

  20. Concentrated sunlight for organic solar cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    2010-01-01

    Concentrated sunlight provides a novel approach to the study of the physical and electrical parameters of organic solar cells. The study of performance of organic solar cells at high solar concentrations provides insight into the physics, which cannot be studied with conventional solar simulators....... A high solar intensity study of inverted P3HT:PCBM solar cells is presented. Performance peak positions were found to be in the range of 1-5 suns, with smaller cells peaking at higher solar concentrations. Additionally, concentrated sunlight is demonstrated as a practical tool for accelerated stability...... studies of polymers for organic solar cells. Degradation was monitored by the evolution of the UV-vis absorption over time. Varying the solar intensity from 1 to 200 suns, the degradation rates were increased by more than a factor of 100 relative to degradation at 1 simulated sun. 5 different polymers...

  1. Concentrated sunlight for organic solar cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    2010-01-01

    Concentrated sunlight provides a novel approach to the study of the physical and electrical parameters of organic solar cells. The study of performance of organic solar cells at high solar concentrations provides insight into the physics, which cannot be studied with conventional solar simulators...... studies of polymers for organic solar cells. Degradation was monitored by the evolution of the UV-vis absorption over time. Varying the solar intensity from 1 to 200 suns, the degradation rates were increased by more than a factor of 100 relative to degradation at 1 simulated sun. 5 different polymers....... A high solar intensity study of inverted P3HT:PCBM solar cells is presented. Performance peak positions were found to be in the range of 1-5 suns, with smaller cells peaking at higher solar concentrations. Additionally, concentrated sunlight is demonstrated as a practical tool for accelerated stability...

  2. Sunlight induced photo reactivity of drugs

    Energy Technology Data Exchange (ETDEWEB)

    Dallera, R.; Dondi, D.; Ricci, A.; Fasani, E.; Albini, A.

    2003-07-01

    The reactivity under natural light of some UVA-UVB photol able drugs belonging to the classes of fluoroquinolones, glucocortocosteroids, sunscreens and nitrophenyldihydropyridines has been investigated. The data suggest that exposition to sunlight for times ranging from some minutes to few hours at PSA is sufficient for promoting a high degradation in the drugs investigated. the chemical reactions are the same as observed under artificial UV light. (Author) 28 refs.

  3. Multiple clusters of release sites formed by individual thalamic afferents onto cortical interneurons ensure reliable transmission.

    Science.gov (United States)

    Bagnall, Martha W; Hull, Court; Bushong, Eric A; Ellisman, Mark H; Scanziani, Massimo

    2011-07-14

    Thalamic afferents supply the cortex with sensory information by contacting both excitatory neurons and inhibitory interneurons. Interestingly, thalamic contacts with interneurons constitute such a powerful synapse that even one afferent can fire interneurons, thereby driving feedforward inhibition. However, the spatial representation of this potent synapse on interneuron dendrites is poorly understood. Using Ca imaging and electron microscopy we show that an individual thalamic afferent forms multiple contacts with the interneuronal proximal dendritic arbor, preferentially near branch points. More contacts are correlated with larger amplitude synaptic responses. Each contact, consisting of a single bouton, can release up to seven vesicles simultaneously, resulting in graded and reliable Ca transients. Computational modeling indicates that the release of multiple vesicles at each contact minimally reduces the efficiency of the thalamic afferent in exciting the interneuron. This strategy preserves the spatial representation of thalamocortical inputs across the dendritic arbor over a wide range of release conditions.

  4. HISTORY OF SUNLIGHT EXPOSURE IS A RISK FACTOR FOR AGE-RELATED MACULAR DEGENERATION.

    Science.gov (United States)

    Schick, Tina; Ersoy, Lebriz; Lechanteur, Yara T E; Saksens, Nicole T M; Hoyng, Carel B; den Hollander, Anneke I; Kirchhof, Bernd; Fauser, Sascha

    2016-04-01

    To evaluate effects of current and past sunlight exposure and iris color on early and late age-related macular degeneration (AMD). Of 3,701 individuals from the EUGENDA database, 752 (20.3%) showed early AMD, 1,179 (31.9%) late AMD, and 1,770 (47.8%) were controls. Information about current and past sunlight exposure, former occupation type, subdivided in indoor working and outdoor working, and iris color were obtained by standardized interviewer-assisted questionnaires. Associations between environmental factors adjusted for age, gender, and smoking and early and late AMD were performed by multivariate regression analysis. Current sunlight exposure showed no association with early AMD or late AMD, but past sunlight exposure (≥8 hours outside daily) was significantly associated with early AMD (odds ratio: 5.54, 95% confidence interval 1.25-24.58, P = 0.02) and late AMD (odds ratio: 2.77, 95% confidence interval 1.25-6.16, P = 0.01). Outside working was found to be associated with late AMD (odds ratio: 2.57, 95% confidence interval 1.89-3.48, P = 1.58 × 10). No association was observed between iris color and early or late AMD. Sunlight exposure during working life is an important risk factor for AMD, whereas sunlight exposure after retirement seems to have less influence on the disease development. Therefore, preventive measures, for example, wearing sunglasses to minimize sunlight exposure, should start early to prevent development of AMD later in life.

  5. Sunlight exposure assessment: can we accurately assess vitamin D exposure from sunlight questionnaires?

    Science.gov (United States)

    McCarty, Catherine A

    2008-04-01

    The purpose of this review is to summarize the peer-reviewed literature in relation to sunlight exposure assessment and the validity of using sunlight exposure questionnaires to quantify vitamin D status. There is greater variability in personal ultraviolet (UV) light exposure as the result of personal behavior than as the result of ambient UV light exposure. Although statistically significant, the correlation coefficients for the relation between personal report of sun exposure and ambient UV light measured by dosimetry (assessment of radiation dose) are relatively low. Moreover, the few studies to assess the relation between sunlight measures and serum 25-hydroxyvitamin D show low correlations. These low correlations may not be surprising given that personal factors like melanin content in skin and age also influence cutaneous synthesis of vitamin D. In summary, sunlight exposure questionnaires currently provide imprecise estimates of vitamin D status. Research should be directed to develop more objective, nonintrusive, and economical measures of sunlight exposure to quantify personal vitamin D status.

  6. Assessment Data-Informed Guidance to Individualize Kindergarten Reading Instruction: Findings from a Cluster-Randomized Control Field Trial.

    Science.gov (United States)

    Al Otaiba, Stephanie; Connor, Carol M; Folsom, Jessica Sidler; Greulich, Luana; Meadows, Jane; Li, Zhi

    2011-06-01

    The purpose of this cluster-randomized control field trial was to was to examine the extent to which kindergarten teachers could learn a promising instructional strategy, wherein kindergarten reading instruction was differentiated based upon students' ongoing assessments of language and literacy skills and documented child characteristic by instruction (CXI) interactions; and to test the efficacy of this differentiated reading instruction on the reading outcomes of students from culturally diverse backgrounds. The study involved 14 schools and included 23 treatment (n = 305 students) and 21 contrast teacher (n = 251 students). Teachers in the contrast condition received only a baseline professional development that included a researcher-delivered summer day-long workshop on individualized instruction. Data sources included parent surveys, individually administered child assessments of language, cognitive, and reading skills and videotapes of classroom instruction. Using Hierarchical Multivariate Linear Modeling (HMLM), we found students in treatment classrooms outperformed students in the contrast classrooms on a latent measure of reading skills, comprised of letter-word reading, decoding, alphabetic knowledge, and phonological awareness (ES = .52). Teachers in both conditions provided small group instruction, but teachers in the treatment condition provided significantly more individualized instruction. Our findings extend research on the efficacy of teachers using Individualized Student Instruction to individualize instruction based upon students' language and literacy skills in first through third grade. Findings are discussed regarding the value of professional development related to differentiating core reading instruction and the challenges of using Response to Intervention approaches to address students' needs in the areas of reading in general education contexts.

  7. HISTORY OF SUNLIGHT EXPOSURE IS A RISK FACTOR FOR AGE-RELATED MACULAR DEGENERATION

    NARCIS (Netherlands)

    Schick, T.; Ersoy, L.; Lechanteur, Y.T.; Saksens, N.T.; Hoyng, C.B.; Hollander, A.I. den; Kirchhof, B.; Fauser, S.

    2016-01-01

    PURPOSE: To evaluate effects of current and past sunlight exposure and iris color on early and late age-related macular degeneration (AMD). METHODS: Of 3,701 individuals from the EUGENDA database, 752 (20.3%) showed early AMD, 1,179 (31.9%) late AMD, and 1,770 (47.8%) were controls. Information abou

  8. Commonly recommended daily intake of vitamin D is not sufficient if sunlight exposure is limited

    DEFF Research Database (Denmark)

    Glerup, H; Mikkelsen, K; Poulsen, L

    2000-01-01

    intake analysis to estimate the oral intake of vitamin D necessary to keep a normal vitamin D status in sunlight-deprived individuals. DESIGN: Cross-sectional study amongst randomly selected Moslem women of Arab origin living in Denmark. Age-matched Danish women were included as controls. To control...

  9. HISTORY OF SUNLIGHT EXPOSURE IS A RISK FACTOR FOR AGE-RELATED MACULAR DEGENERATION

    NARCIS (Netherlands)

    Schick, T.; Ersoy, L.; Lechanteur, Y.T.; Saksens, N.T.; Hoyng, C.B.; Hollander, A.I. den; Kirchhof, B.; Fauser, S.

    2016-01-01

    PURPOSE: To evaluate effects of current and past sunlight exposure and iris color on early and late age-related macular degeneration (AMD). METHODS: Of 3,701 individuals from the EUGENDA database, 752 (20.3%) showed early AMD, 1,179 (31.9%) late AMD, and 1,770 (47.8%) were controls. Information abou

  10. Socioeconomic status, sunlight exposure, and risk of malignant melanoma: the Western Canada Melanoma Study.

    Science.gov (United States)

    Gallagher, R P; Elwood, J M; Threlfall, W J; Spinelli, J J; Fincham, S; Hill, G B

    1987-10-01

    In a study of 261 male melanoma patients and age-and sex-matched controls, a strong positive univariate association between socioeconomic status, as determined by usual occupation, and risk of melanoma was detected. This association, however, was substantially explained by host constitutional factors and occupational, recreational, and vacation sunlight exposure. The study demonstrated an increased risk of melanoma in draftsmen and surveyors and a reduced risk of melanoma in construction workers and individuals employed in the finance, insurance, and real estate industry even after control for the effect of host factors and sunlight exposure.

  11. Persistence of benthiocarb in soil: influence of ultraviolet and sunlight

    Directory of Open Access Journals (Sweden)

    Md. Wasim Aktar

    2008-12-01

    Full Text Available Persistence of benthiocarb in soil as affected by UV and sunlight exposure was studied. Treated soil was placed in petri plate, brought to field capacity moisture and then exposed to UV and sunlight. Residues of benthiocarb in soil dissipated with half lives of 2.10, 11.85 and 43.63 days under UV, sunlight and dark condition, respectively. Soil samples kept under dark showed the slowest dissipation. Further, benthiocarb residues dissipated quickly under UV light as compared to sunlight. Exposure of thin film of benthiocarb confirmed that it is photo labile and dissipated very fast with half life of 1.16 and 1.77 days following exposure to UV and sunlight, respectively. The study revealed that UV component of sunlight is an important factor for benthiocarb dissipation.

  12. South African university student knowledge of eye protection against sunlight

    OpenAIRE

    O. A. Oduntan; A. Carelson; P. Clarke-Farr; R. Hansraj

    2009-01-01

    Exposure to sunlight has been associated with several ocular conditions such as cataract, age-related macular degeneration, and conjunctival neoplasm. Knowledge of protective modalities and good behavioural practice involving eye protection is essential to prevent adverse effects of sunlight. The purpose of this study was to establish knowledge amongst randomly selected university students in South Africa, of prevention modalities against the adverse effects of sunlight. A questionnaire relat...

  13. Individual music therapy for managing neuropsychiatric symptoms for people with dementia and their carers: a cluster randomised controlled feasibility study.

    Science.gov (United States)

    Hsu, Ming Hung; Flowerdew, Rosamund; Parker, Michael; Fachner, Jörg; Odell-Miller, Helen

    2015-07-18

    Previous research highlights the importance of staff involvement in psychosocial interventions targeting neuropsychiatric symptoms of dementia. Music therapy has shown potential effects, but it is not clear how this intervention can be programmed to involve care staff within the delivery of patients' care. This study reports initial feasibility and outcomes from a five month music therapy programme including weekly individual active music therapy for people with dementia and weekly post-therapy video presentations for their carers in care homes. 17 care home residents and 10 care staff were randomised to the music therapy intervention group or standard care control group. The cluster randomised, controlled trial included baseline, 3-month, 5-month and post-intervention 7-month measures of residents' symptoms and well-being. Carer-resident interactions were also assessed. Feasibility was based on carers' feedback through semi-structured interviews, programme evaluations and track records of the study. The music therapy programme appeared to be a practicable and acceptable intervention for care home residents and staff in managing dementia symptoms. Recruitment and retention data indicated feasibility but also challenges. Preliminary outcomes indicated differences in symptoms (13.42, 95 % CI: [4.78 to 22.07; p = 0.006]) and in levels of wellbeing (-0.74, 95 % CI: [-1.15 to -0.33; p = 0.003]) between the two groups, indicating that residents receiving music therapy improved. Staff in the intervention group reported enhanced caregiving techniques as a result of the programme. The data supports the value of developing a music therapy programme involving weekly active individual music therapy sessions and music therapist-carer communication. The intervention is feasible with modifications in a more rigorous evaluation of a larger sample size. Clinicaltrials.gov, number NCT01744600.

  14. Photocatalytic oxidation of ciprofloxacin under simulated sunlight.

    Science.gov (United States)

    Gad-Allah, Tarek A; Ali, Mohamed E M; Badawy, Mohamed I

    2011-02-15

    Ciprofloxacin (CIP) is a famous synthetic chemotherapeutic antibiotic. It is widely found either in water or wastewater. In this study ciprofloxacin was photocatalytically degraded using commercial anatase titanium dioxide (TiO(2)) under simulated sunlight. The rate of reaction was found to be affected by pH, TiO(2) concentration and antibiotic concentration. The best reaction rate was obtained in natural ciprofloxacin pH (5.8) and 1000 mg/L TiO(2). More titania concentration was found to reduce the reaction rate because of the limitation in light transmittance. From kinetic studies, the reaction was proved to proceed through adsorption step then photooxidation and obeys pseudo-first order kinetics. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Development and validation of sunlight exposure measurement questionnaire (SEM-Q) for use in adult population residing in Pakistan.

    Science.gov (United States)

    Humayun, Quratulain; Iqbal, Romaina; Azam, Iqbal; Khan, Aysha Habib; Siddiqui, Amna Rehana; Baig-Ansari, Naila

    2012-06-08

    Vitamin D deficiency has been identified as a major public health problem worldwide. Sunlight is the main source of vitamin D and its measurement using dosimeters is expensive and difficult for use in population-based studies. Hence, the aim of this study was to develop and validate questionnaires to assess sunlight exposure in healthy individuals residing in Karachi, Pakistan. Two questionnaires with seven important items for sunlight exposure assessment were developed. Fifty four healthy adults were enrolled based on their reported sunlight exposure (high = 17, moderate = 18, low = 19) from Aga Khan University, Karachi. Over four days, study participants were asked to wear a dosimeter between sunrise and sunset and report time spent and activities undertaken in the sun for questionnaire validation. Algorithm for item weightage was created as an average score based on ultraviolet B percentage received. Blood samples were obtained for serum vitamin D. The mean time (minutes) spent in sun over 4 days (±SD) was 69.5 (±32) for low, 83.5 (±29.7) for moderate and 329 (±115) for high exposure group. The correlation between average time (minutes) spent in sun over 4 days and mean change in absorbance of UV dosimeters for 4 days was 0.60 (p sunlight exposure measurement questionnaires were valid tools for use in large epidemiological studies to quantify sunlight exposure.

  16. Recommended summer sunlight exposure amounts fail to produce sufficient vitamin D status in UK adults of South Asian origin.

    Science.gov (United States)

    Farrar, Mark D; Kift, Richard; Felton, Sarah J; Berry, Jacqueline L; Durkin, Marie T; Allan, Donald; Vail, Andy; Webb, Ann R; Rhodes, Lesley E

    2011-11-01

    The cutaneous synthesis of vitamin D is dependent on UVB from sunlight, but melanin reduces the penetration of UVB and thus contributes to vitamin D insufficiency in individuals with darker skin. The national guidance provided on amounts of sunlight exposure in the United Kingdom is for the light-skinned population, and in the absence of dedicated information, darker-skinned people may attempt to follow this guidance. We determined the relative effect of a simulation of UK recommendations of summer sunlight exposure on the vitamin D status of individuals of South Asian ethnicity compared with that of whites. In a prospective cohort study, simulated summer sunlight exposures were provided under rigorous dosimetric conditions to 15 adults (aged 20-60 y) of South Asian ethnicity, and serum 25-hydroxyvitamin D [25(OH)D] was measured weekly. Dietary vitamin D intake was estimated. Outcomes were compared with those of 109 whites (aged 20-60 y) treated with the identical UV-radiation exposure protocol. At baseline (winter trough), all South Asians were vitamin D-insufficient [25(OH)D concentrations Sunlight-exposure recommendations are inappropriate for individuals of South Asian ethnicity who live at the UK latitude. More guidance is required to meet the vitamin D requirements of this sector of the population. This study was registered at www.isrctn.org as ISRCTN 07565297.

  17. Cluster-cluster clustering

    Science.gov (United States)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C. S.

    1985-01-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales.

  18. Cluster-cluster clustering

    Energy Technology Data Exchange (ETDEWEB)

    Barnes, J.; Dekel, A.; Efstathiou, G.; Frenk, C.S.

    1985-08-01

    The cluster correlation function xi sub c(r) is compared with the particle correlation function, xi(r) in cosmological N-body simulations with a wide range of initial conditions. The experiments include scale-free initial conditions, pancake models with a coherence length in the initial density field, and hybrid models. Three N-body techniques and two cluster-finding algorithms are used. In scale-free models with white noise initial conditions, xi sub c and xi are essentially identical. In scale-free models with more power on large scales, it is found that the amplitude of xi sub c increases with cluster richness; in this case the clusters give a biased estimate of the particle correlations. In the pancake and hybrid models (with n = 0 or 1), xi sub c is steeper than xi, but the cluster correlation length exceeds that of the points by less than a factor of 2, independent of cluster richness. Thus the high amplitude of xi sub c found in studies of rich clusters of galaxies is inconsistent with white noise and pancake models and may indicate a primordial fluctuation spectrum with substantial power on large scales. 30 references.

  19. Photocatalytic degradation of synthetic dye under sunlight

    Directory of Open Access Journals (Sweden)

    Mijin Dušan

    2007-01-01

    Full Text Available Synthetic dyes are widely used in the textile industry. Dye pollutants from the textile industry are an important source of environmental contamination. The majority of these dyes are toxic, mostly non-biodegradable and also resistant to decomposition by physico-chemical methods. Among new oxidation methods or "advanced oxidation processes", heterogeneous photocatalysis appears as an emerging destructive technology leading to the total mineralization of many organic pollutants. CI Basic Yellow 28 (BY28, commonly used as a textile dye, could be photocatalytically degraded using TiU2 as catalyst under sunlight. The effect of some parameters such as the initial catalyst concentration, initial dye concentration, initial NaCl and Na2CO3 concentrations, pH, H2O2 and type of catalyst on the degradation rate of BY28 was examined in details. The presence of NaCl and Na2CO3 led to inhibition of the photodegradation process. The highest photodegradation rate was observed at high pH, while the rate was the lowest at low pH. Increase of the initial H2O2 concentration increased the initial BY28 photodegradation efficiency. ZnO was a better catalyst than TiO2 at low dye concentrations.

  20. Grape anthocyanin altered by absolute sunlight exclusion

    Science.gov (United States)

    This research was conducted to clarify anthocyanin accumulation within ‘Merlot’ grapes in response to microclimate, specifically to light incidence, temperature, and humidity. Treatment grape clusters were light-excluded during ripening by opaque white polypropylene enclosures, during which light in...

  1. Sunlight, ultraviolet radiation, vitamin D and skin cancer: how much sunlight do we need?

    Science.gov (United States)

    Holick, Michael F

    2014-01-01

    Vitamin D is the sunshine vitamin for good reason. During exposure to sunlight, the UV B photons enter the skin and photolyze 7-dehydrocholesterol to previtamin D3 which in turn is isomerized by the body's temperature to vitamin D3. Most humans have depended on sun for their vitamin D requirement. Skin pigment, sunscreen use, aging, time of day, season and latitude dramatically affect previtamin 13 synthesis. Vitamin D deficiency was thought to have been conquered, but it is now recognized that more than 50% of the world's population is at risk for vitamin D deficiency. This deficiency is in part due to the inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D. Vitamin D deficiency causes growth retardation and rickets in children and will precipitate and exacerbate osteopenia, osteoporosis and increase risk of fracture in adults. The vitamin D deficiency has been associated pandemic with other serious consequences including increased risk of common cancers, autoimmune diseases, infectious diseases and cardiovascular disease. There needs to be a renewed appreciation of the beneficial effect of moderate sunlight for providing all humans with their vitamin D requirement for health.

  2. Direct and Indirect Phototransformation of Graphene Oxide in Sunlight

    Science.gov (United States)

    Direct and indirect (with added H202 that serves as OH precursor) photoreactions of grapheme oxide (GO) were examined under sunlight exposure. The results indicate that GO photoreacts under both conditions, leading to significant alterations in GO's physicochemical properties. In...

  3. Sunlight exposure-mediated DNA damage in young adults.

    Science.gov (United States)

    Kato, Masashi; Iida, Machiko; Goto, Yuji; Kondo, Takaaki; Yajima, Ichiro

    2011-08-01

    Previous experimental studies showed that single ultraviolet B (UVB) light irradiation increased levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG), a well-established biomarker of carcinogenesis and oxidative DNA damage, in epithelial cells in animals and humans. We conducted for the first time an epidemiologic study to investigate the correlations among levels of oxidative DNA damage, skin pigmentation, and sunlight exposure in human daily life. Digitalized skin pigmentation levels and creatinine-adjusted urinary 8-OHdG levels were examined in 127 healthy young adults aged 20 to 24 years and in hairless mice with normal pigmented skin (HL-mice; n = 20) and hyperpigmented skin (HL-HPS-mice; n = 20). Data obtained by a questionnaire were also analyzed for the 127 subjects. Binary logistic regression analysis showed that increased sunlight intensity, but not sunlight-exposed time or sunlight-exposed skin area, was correlated with elevation in creatinine-adjusted urinary 8-OHdG levels. In contrast, increased skin pigmentation level, but not the use of sunscreen, was correlated with reduction in urinary 8-OHdG level in humans. UVB irradiation corresponding to several minutes of sunlight exposure significantly increased urinary 8-OHdG levels in HL-mice but not in HL-HPS-mice. We showed that increase in intensity of sunlight in human daily life increased levels of DNA damage. We also showed a protective effect of skin pigmentation on sunlight exposure-mediated DNA damage. We have provided more reliable evidence of routine sunlight exposure-mediated DNA damage in humans through the combination of epidemiologic and experimental studies. ©2011 AACR.

  4. Accelerated stability testing of organic photovoltaics using concentrated sunlight

    DEFF Research Database (Denmark)

    Katz, Eugene A.; Manor, Assaf; Mescheloff, Asaf;

    2012-01-01

    We suggest to use concentrated sunlight for accelerated studies of light-induced mechanisms in the degradation of organic photovoltaics (OPV) based on the polymer (P3HT)/fullerene (PCBM) bulk heterojunctions. Two particular cases of the degradation are reported.......We suggest to use concentrated sunlight for accelerated studies of light-induced mechanisms in the degradation of organic photovoltaics (OPV) based on the polymer (P3HT)/fullerene (PCBM) bulk heterojunctions. Two particular cases of the degradation are reported....

  5. No indications for an ultraviolet B radiation induced decline of immunological parameters after sunlight exposure among HIV infected homosexual men

    NARCIS (Netherlands)

    Maas J; Termorshuizen F; Geskus RB; Coutinho RA; Loveren H van; GG&GD Amsterdam; LPI

    2000-01-01

    Whether sunlight (especially ultraviolet B radiation: UVB) exposure is harmful to the cellular immunity of HIV infected individuals and whether it is associated with an accelerated progression toward AIDS is still under debate. Among HIV+ homosexual participants of the Amsterdam Cohort Study, the de

  6. No indications for an ultraviolet B radiation induced decline of immunological parameters after sunlight exposure among HIV infected homosexual men

    NARCIS (Netherlands)

    Maas J; Termorshuizen F; Geskus RB; Coutinho RA; Loveren H van; GG&GD Amsterdam; LPI

    2000-01-01

    Whether sunlight (especially ultraviolet B radiation: UVB) exposure is harmful to the cellular immunity of HIV infected individuals and whether it is associated with an accelerated progression toward AIDS is still under debate. Among HIV+ homosexual participants of the Amsterdam Cohort Study, the de

  7. Sunlight exposure and multiple sclerosis in a tropical country.

    Science.gov (United States)

    Espinosa-Ramírez, Guillermo; Ordoñez, Graciela; Flores-Rivera, Jose; Sotelo, Julio

    2014-07-01

    We analysed past and current sun exposure in multiple sclerosis (MS) patients as compared with matched controls in Mexico, a country with tropical climate. In a case-controlled study that include 83 MS patients and 166 matched controls, we inquired about sunlight exposure in two different periods: during adolescence and during the immediate past 5 years. Indicators were: exposure on quotidian and weekend outdoor activities with direct sunlight contact as expressed on frequency by mean number of days, daytime (morning, noon, afternoon), number of hours, visits to sunny places, and use of sunblocking agents. Additional elements were socioeconomic status, skin colour, and antecedent of varicella infection during childhood. MS patients showed a larger proportion of white skin. MS patients had more sunlight exposure during adolescence (80% versus 60%, P = 0·002); this tendency prevailed on current indicators (46% versus 30%, P = 0·02). However, current exposure on weekends (10% versus 22%, P = 0·02) and visits to the beach (64% versus 98%, P = 0·002) were lower in MS than in controls. Mexico gets more sunlight through the year than areas with high incidence of MS; nevertheless, its prevalence has greatly increased over the last decades, making it a relevant emerging disease. Our results indicate that in a tropical country, there is no association between sunlight exposure and the risk to develop MS, given the immunological effects of sunlight exposure either through UV radiation or vitamin D metabolism.

  8. Effect of Natural Sunlight on Bacterial Activity and Differential Sensitivity of Natural Bacterioplankton Groups in Northwestern Mediterranean Coastal Waters

    Science.gov (United States)

    Alonso-Sáez, Laura; Gasol, Josep M.; Lefort, Thomas; Hofer, Julia; Sommaruga, Ruben

    2006-01-01

    We studied the effects of natural sunlight on heterotrophic marine bacterioplankton in short-term experiments. We used a single-cell level approach involving flow cytometry combined with physiological probes and microautoradiography to determine sunlight effects on the activity and integrity of the cells. After 4 h of sunlight exposure, most bacterial cells maintained membrane integrity and viability as assessed by the simultaneous staining with propidium iodide and SYBR green I. In contrast, a significant inhibition of heterotrophic bacterial activity was detected, measured by 5-cyano-2,3 ditolyl tetrazolium chloride reduction and leucine incorporation. We applied microautoradiography combined with catalyzed reporter deposition-fluorescence in situ hybridization to test the sensitivity of the different bacterial groups naturally occurring in the Northwestern Mediterranean to sunlight. Members of the Gammaproteobacteria and Bacteroidetes groups appeared to be highly resistant to solar radiation, with small changes in activity after exposure. On the contrary, Alphaproteobacteria bacteria were more sensitive to radiation as measured by the cell-specific incorporation of labeled amino acids, leucine, and ATP. Within Alphaproteobacteria, bacteria belonging to the Roseobacter group showed higher resistance than members of the SAR11 cluster. The activity of Roseobacter was stimulated by exposure to photosynthetic available radiation compared to the dark treatment. Our results suggest that UV radiation can significantly affect the in situ single-cell activity of bacterioplankton and that naturally dominating phylogenetic bacterial groups have different sensitivity to natural levels of incident solar radiation. PMID:16957198

  9. Life-threatening motor vehicle crashes in bright sunlight.

    Science.gov (United States)

    Redelmeier, Donald A; Raza, Sheharyar

    2017-01-01

    Bright sunlight may create visual illusions that lead to driver error, including fallible distance judgment from aerial perspective. We tested whether the risk of a life-threatening motor vehicle crash was increased when driving in bright sunlight.This longitudinal, case-only, paired-comparison analysis evaluated patients hospitalized because of a motor vehicle crash between January 1, 1995 and December 31, 2014. The relative risk of a crash associated with bright sunlight was estimated by evaluating the prevailing weather at the time and place of the crash compared with the weather at the same hour and location on control days a week earlier and a week later.The majority of patients (n = 6962) were injured during daylight hours and bright sunlight was the most common weather condition at the time and place of the crash. The risk of a life-threatening crash was 16% higher during bright sunlight than normal weather (95% confidence interval: 9-24, P vehicle crash. An awareness of this risk might inform driver education, trauma staffing, and safety warnings to prevent a life-threatening motor vehicle crash.

  10. Hair cortisol and cortisone are decreased by natural sunlight.

    Science.gov (United States)

    Wester, Vincent L; van der Wulp, Nils R P; Koper, Jan W; de Rijke, Yolanda B; van Rossum, Elisabeth F C

    2016-10-01

    Hair glucocorticoids (cortisol and cortisone) are increasingly used as measures of long-term integrated exposure to glucocorticoid hormones. Glucocorticoids gradually disappear from the hair shaft, which may result from exposure to ultraviolet (UV) radiation in natural sunlight. We aimed to study the influence of sun exposure on hair glucocorticoids. Scalp hair samples were obtained from nine volunteers (median age 33 [range 21-81], 7 females), and part of each hair sample was exposed to three experimental conditions: repeated exposure to natural sunlight for 40h (natural UV), exposure to a high amount of artificial UV radiation, and storage in the dark (control). Hair cortisol (HairF) and cortisone (HairE) were quantified by liquid chromatography-tandem mass spectrometry. When compared to control, HairF was decreased in 9 out of 9 hair samples after natural sunlight exposure (median decrease -3.1pg/mg or -54%, PUV radiation (-4.7pg/mg or -75%, P=0.003). HairE decreased in 8 out of 9 samples, both after natural sunlight (-7.6pg/mg or -32%, P=0.012) and artificial UV (-10.7pg/mg or -52%, P=0.026). Exposure to natural sunlight decreases the glucocorticoid content of scalp hair, apparently through UV radiation, and is therefore an important confounder that should be considered in studies involving the measurement of hair glucocorticoids. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Testing the origin of ~3.55 keV line in individual galaxy clusters observed with XMM-Newton

    CERN Document Server

    Iakubovskyi, Dmytro; Foster, Adam R; Savchenko, Denys; Sadova, Valentyna

    2015-01-01

    If the unidentified emission line at ~3.55 keV previously found in spectra of nearby galaxies and galaxy clusters is due to radiatively decaying dark matter, one should detect the signal of comparable strength from many cosmic objects of different nature. By studying existing dark matter distributions in galaxy clusters we identified top-19 of them observed by XMM-Newton X-ray cosmic mission, and analyzed the data for the presence of the new line. In 8 of them, we identified > 2 sigma positive line-like residuals with average position 3.52 +/- 0.08 keV in the emitter's frame. Their observed properties are unlikely to be explained by statistical fluctuations or astrophysical emission lines; observed line position in M31 and Galactic Center makes an additional argument against general-type systematics. Being interpreted as decaying dark matter line, the new detections correspond to radiative decay lifetime tau_dm ~ (3.5-6) x 10^27 s consistent with previous detections.

  12. Childhood cancer incidence in relation to sunlight exposure.

    Science.gov (United States)

    Musselman, J R B; Spector, L G

    2011-01-04

    There is increasing interest in the possible association between cancer incidence and vitamin D through its role as a regulator of cell growth and differentiation. Epidemiological studies in adults and one paediatric study suggest an inverse association between sunlight exposure and cancer incidence. We carried out an ecological study using childhood cancer registry data and two population-level surrogates of sunlight exposure, (1) latitude of the registry city or population centroid of the registry nation and (2) annual solar radiation. All models were adjusted for nation-level socioeconomic status using socioeconomic indicators. Latitude and radiation were significantly associated with cancer incidence, and the direction of association was consistent between the surrogates. Findings were not consistent across tumour types. Our ecological study offers some evidence to support an association between sunlight exposure and risk of childhood cancer.

  13. Reversible degradation of inverted organic solar cells by concentrated sunlight

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Manor, Assaf; Katz, Eugene A

    2011-01-01

    Concentrated sunlight was used to study the performance response of inverted P3HT:PCBM organic solar cells after exposure to high intensity sunlight. Correlations of efficiency as a function of solar intensity were established in the range of 0.5–15 suns at three different stages: for a pristine....... The transient state is believed to be a result of the breakdown of the diode behaviour of the ZnO electron transport layer by O2 desorption, increasing the hole conductivity. These results imply that accelerated degradation of organic solar cells by concentrated sunlight is not a straightforward process...... cell, after 30 min exposure at 5 suns and after 30 min of rest in the dark. High intensity exposure introduced a major performance decrease for all solar intensities, followed by a partial recovery of the lost performance over time: at 1 sun only 6% of the initial performance was conserved after...

  14. Carbon nanohorns-based nanofluids as direct sunlight absorbers.

    Science.gov (United States)

    Sani, E; Barison, S; Pagura, C; Mercatelli, L; Sansoni, P; Fontani, D; Jafrancesco, D; Francini, F

    2010-03-01

    The optimization of the poor heat transfer characteristics of fluids conventionally employed in solar devices are at present one of the main topics for system efficiency and compactness. In the present work we investigated the optical and thermal properties of nanofluids consisting in aqueous suspensions of single wall carbon nanohorns. The characteristics of these nanofluids were evaluated in view of their use as sunlight absorber fluids in a solar device. The observed nanoparticle-induced differences in optical properties appeared promising, leading to a considerably higher sunlight absorption. We found that the thermal conductivity of the nanofluids was higher than pure water. Both these effects, together with the possible chemical functionalization of carbon nanohorns, make this new kind of nanofluids very interesting for increasing the overall efficiency of the sunlight exploiting device.

  15. Life-threatening motor vehicle crashes in bright sunlight

    Science.gov (United States)

    Redelmeier, Donald A.; Raza, Sheharyar

    2017-01-01

    Abstract Bright sunlight may create visual illusions that lead to driver error, including fallible distance judgment from aerial perspective. We tested whether the risk of a life-threatening motor vehicle crash was increased when driving in bright sunlight. This longitudinal, case-only, paired-comparison analysis evaluated patients hospitalized because of a motor vehicle crash between January 1, 1995 and December 31, 2014. The relative risk of a crash associated with bright sunlight was estimated by evaluating the prevailing weather at the time and place of the crash compared with the weather at the same hour and location on control days a week earlier and a week later. The majority of patients (n = 6962) were injured during daylight hours and bright sunlight was the most common weather condition at the time and place of the crash. The risk of a life-threatening crash was 16% higher during bright sunlight than normal weather (95% confidence interval: 9–24, P < 0.001). The increased risk was accentuated in the early afternoon, disappeared at night, extended to patients with different characteristics, involved crashes with diverse features, not apparent with cloudy weather, and contributed to about 5000 additional patient-days in hospital. The increased risk extended to patients with high crash severity as indicated by ambulance involvement, surgical procedures, length of hospital stay, intensive care unit admission, and patient mortality. The increased risk was not easily attributed to differences in alcohol consumption, driving distances, or anomalies of adverse weather. Bright sunlight is associated with an increased risk of a life-threatening motor vehicle crash. An awareness of this risk might inform driver education, trauma staffing, and safety warnings to prevent a life-threatening motor vehicle crash. Level of evidence: Epidemiologic Study, level III. PMID:28072708

  16. Successful pacing using a batteryless sunlight-powered pacemaker.

    Science.gov (United States)

    Haeberlin, Andreas; Zurbuchen, Adrian; Schaerer, Jakob; Wagner, Joerg; Walpen, Sébastien; Huber, Christoph; Haeberlin, Heinrich; Fuhrer, Juerg; Vogel, Rolf

    2014-10-01

    Today's cardiac pacemakers are powered by batteries with limited energy capacity. As the battery's lifetime ends, the pacemaker needs to be replaced. This surgical re-intervention is costly and bears the risk of complications. Thus, a pacemaker without primary batteries is desirable. The goal of this study was to test whether transcutaneous solar light could power a pacemaker. We used a three-step approach to investigate the feasibility of sunlight-powered cardiac pacing. First, the harvestable power was estimated. Theoretically, a subcutaneously implanted 1 cm(2) solar module may harvest ∼2500 µW from sunlight (3 mm implantation depth). Secondly, ex vivo measurements were performed with solar cells placed under pig skin flaps exposed to a solar simulator and real sunlight. Ex vivo measurements under real sunlight resulted in a median output power of 4941 µW/cm(2) [interquartile range (IQR) 3767-5598 µW/cm(2), median skin flap thickness 3.0 mm (IQR 2.7-3.3 mm)]. The output power strongly depended on implantation depth (ρSpearman = -0.86, P pacemaker powered by a 3.24 cm(2) solar module was implanted in vivo in a pig to measure output power and to pace. In vivo measurements showed a median output power of >3500 µW/cm(2) (skin flap thickness 2.8-3.84 mm). Successful batteryless VVI pacing using a subcutaneously implanted solar module was performed. Based on our results, we estimate that a few minutes of direct sunlight (irradiating an implanted solar module) allow powering a pacemaker for 24 h using a suitable energy storage. Thus, powering a pacemaker by sunlight is feasible and may be an alternative energy supply for tomorrow's pacemakers. Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2014. For permissions please email: journals.permissions@oup.com.

  17. Reversible degradation of inverted organic solar cells by concentrated sunlight

    OpenAIRE

    Tromholt, Thomas; Manor, Assaf; Katz, Eugene A.; Frederik C. Krebs

    2011-01-01

    Concentrated sunlight was used to study the performance response of inverted P3HT:PCBM organic solar cells after exposure to high intensity sunlight. Correlations of efficiency as a function of solar intensity were established in the range of 0.5–15 suns at three different stages: for a pristine cell, after 30 min exposure at 5 suns and after 30 min of rest in the dark. High intensity exposure introduced a major performance decrease for all solar intensities, followed by a partial recovery of...

  18. Cluster Individuals Based on Phenotype and Determine the Risk for Atrial Fibrillation in the PREVEND and Framingham Heart Study Populations

    NARCIS (Netherlands)

    Rienstra, Michiel; Geelhoed, Bastiaan; Yin, Xiaoyan; Siland, Joylene; Vermond, Robert; Mulder, Bart A; Van Der Harst, Pim; Hillege, Hans L; Benjamin, Emelia J; Van Gelder, Isabelle C

    2016-01-01

    BACKGROUND: Risk prediction of atrial fibrillation (AF) is of importance to improve the early diagnosis and treatment of AF. Latent class analysis takes into account the possible existence of classes of individuals each with shared risk factors, and maybe a better method of incorporating the

  19. Low serum BDNF levels in depressed patients cannot be attributed to individual depressive symptoms or symptom cluster

    NARCIS (Netherlands)

    Bus, B. A. A.; Molendijk, M. L.; Penninx, B. W. J. H.; Buitelaar, J. K.; Prickaerts, J.; Elzinga, B. M.; Oude Voshaar, R. C.

    2014-01-01

    OBJECTIVES: Low serum BDNF levels have been found in depressed patients. No study has systematically investigated whether individual symptoms or symptom profiles within a depressed population contribute to low BDNF levels found in depressed subjects. METHODS: All 1070 patients with a past 6-month di

  20. Cluster Individuals Based on Phenotype and Determine the Risk for Atrial Fibrillation in the PREVEND and Framingham Heart Study Populations

    NARCIS (Netherlands)

    Rienstra, Michiel; Geelhoed, Bastiaan; Yin, Xiaoyan; Siland, Joylene; Vermond, Robert; Mulder, Bart A; Van Der Harst, Pim; Hillege, Hans L; Benjamin, Emelia J; Van Gelder, Isabelle C

    2016-01-01

    BACKGROUND: Risk prediction of atrial fibrillation (AF) is of importance to improve the early diagnosis and treatment of AF. Latent class analysis takes into account the possible existence of classes of individuals each with shared risk factors, and maybe a better method of incorporating the phenoty

  1. A longitudinal cluster-randomized controlled study on the accumulating effects of individualized literacy instruction on students' reading from first through third grade.

    Science.gov (United States)

    Connor, Carol McDonald; Morrison, Frederick J; Fishman, Barry; Crowe, Elizabeth C; Al Otaiba, Stephanie; Schatschneider, Christopher

    2013-08-01

    Using a longitudinal cluster-randomized controlled design, we examined whether students' reading outcomes differed when they received 1, 2, or 3 years of individualized reading instruction from first through third grade, compared with a treated control group. More than 45% of students came from families living in poverty. Following students, we randomly assigned their teachers each year to deliver individualized reading instruction or a treated control condition intervention focused on mathematics. Students who received individualized reading instruction in all three grades showed the strongest reading skills by the end of third grade compared with those who received fewer years of such instruction. There was inconsistent evidence supporting a sustained first-grade treatment effect: Individualized instruction in first grade was necessary but not sufficient for stronger third-grade reading outcomes. These effects were achieved by regular classroom teachers who received professional development, which indicates that policies that support the use of evidence-based reading instruction and teacher training can yield increased student achievement.

  2. Lack of sunlight exposure influence on primary glioblastoma survival.

    Science.gov (United States)

    Mutlu, Hasan; Akca, Zeki; Erden, Abdulsamet; Aslan, Tuncay; Ucar, Kadir; Kaplan, Bunyamin; Buyukcelik, Abdullah

    2014-01-01

    The prognosis of primary glioblastoma (GBM) is poor. Approximately 2/3 of primary brain tumor diagnoses are GBM, of which 95% are primary lesions. In this study, we aimed to evaluate whether more sunlight exposure has an effect on survival of patients with primary GBM. A total of 111 patients with primary GBM were enrolled from Kayseri in inner Anatolia which has a cold climate (n: 40) and Mersin in Mediterranean region with a warm climate and more sunlight exposure (n: 71). The patients with primary GBM were divided into two groups as Kayseri and Mersin and compared for progression free survival (PFS) and overall survival (OS). The PFS values were 7.0 and 4.7 months for Kayseri and Mersin groups, respectively (p=0.10) and the respective OS values were 13.3 and 9.4 months (p=0.13). We did not found any significant difference regarding age, sex, comorbidity, smoking, surgery, resurgery, adjuvant chemoradiotherapy and palliative chemotherapy between the groups. We found that more sunlight exposure had no impact on prognosis of patients with primary GBM, adding inconsistency to the literature about the relationship between sunlight and GBM.

  3. [Most common skin disorders caused by excessive exposure to sunlight].

    Science.gov (United States)

    Zitás, Éva; Mészáros, Judit

    2016-01-17

    The healing properties of sunlight has been known for millennia, however the gradual deterioration of the ozone layer and the increased use of sun tanning beds in recent decades are causing an increase in skin damaging ultraviolet exposure. In this article the most common photodermatoses and the principles of their treatments are reviewed.

  4. Reversible degradation of inverted organic solar cells by concentrated sunlight.

    Science.gov (United States)

    Tromholt, Thomas; Manor, Assaf; Katz, Eugene A; Krebs, Frederik C

    2011-06-03

    Concentrated sunlight was used to study the performance response of inverted P3HT:PCBM organic solar cells after exposure to high intensity sunlight. Correlations of efficiency as a function of solar intensity were established in the range of 0.5-15 suns at three different stages: for a pristine cell, after 30 min exposure at 5 suns and after 30 min of rest in the dark. High intensity exposure introduced a major performance decrease for all solar intensities, followed by a partial recovery of the lost performance over time: at 1 sun only 6% of the initial performance was conserved after the high intensity exposure, while after rest the performance had recovered to 60% of the initial value. The timescale of the recovery effect was studied by monitoring the cell performance at 1 sun after high intensity exposure. This showed that cell performance was almost completely restored after 180 min. The transient state is believed to be a result of the breakdown of the diode behaviour of the ZnO electron transport layer by O(2) desorption, increasing the hole conductivity. These results imply that accelerated degradation of organic solar cells by concentrated sunlight is not a straightforward process, and care has to be taken to allow for a sound accelerated lifetime assessment based on concentrated sunlight.

  5. Photochemical transformation of graphene oxide in sunlight (journal)

    Science.gov (United States)

    Graphene oxide (GO) is a graphene derivative that is more easily manufactured in large scale and used to synthesize reduced graphene oxide (rGO) with properties analogous to graphene. In this study, we investigate the photochemical fate of GO under sunlight conditions. The resu...

  6. Electricity from Sunlight: The Future of Photovoltaics. Worldwatch Paper 52.

    Science.gov (United States)

    Flavin, Christopher

    Solar photovoltaic cells have been called the ultimate energy technology, environmentally benign and without moving parts, solar cells directly convert sunlight into electricity. Photovoltaic energy conversion is fundamentally different from all other forms of electricity generation. Without turbines, generators or other mechanical equipment, it…

  7. Vitamin D and Sunlight Exposure in Newly-Diagnosed Parkinson's Disease

    National Research Council Canada - National Science Library

    Wang, Juan; Yang, Deyu; Yu, Yu; Shao, Gaohai; Wang, Qunbo

    2016-01-01

    ...), while the effects of sunlight exposure have not yet been fully investigated. Therefore, we evaluated the associations between serum vitamin D, vitamin D intake, sunlight exposure, and newly-diagnosed PD patients in a Chinese population...

  8. Sunlight Exposure and Vitamin D Status in Breastfed Infants.

    Science.gov (United States)

    Meena, Pinky; Dabas, Aashima; Shah, Dheeraj; Malhotra, Rajeev Kumar; Madhu, S V; Gupta, Piyush

    2017-02-15

    To correlate the sunlight exposure in first 6 months to vitamin D status at 6 months of age in predominantly breastfed infants; and to quantify the sunlight exposure required to achieve serum 25(OH)D level >20 ng/mL, by 6 months of age. Design: Prospective cohort. Tertiary-care hospital predominantly catering to urban poor population in Delhi. 132 healthy infants, delivered at term, and predominantly breastfed were enrolled at 6-8 weeks of age. Of these, 100 infants were available for final evaluation at 6 months of age (mean (SD) follow-up: 126 (17) days). Baseline maternal vitamin D (serum 25(OH)D) levels were obtained at enrolment. The mothers were asked to maintain a daily record of duration of sunlight exposure, timing of exposure, and body surface area exposed, for the infant, on a pre-designed proforma, till the child was 6 months of age. Infant's serum 25(OH)D was measured at 6 months of age. Cumulative Sun Index was calculated as a composite measure of overall duration/time/body surface area exposed to sunlight; and correlated with the infant serum 25(OH)D after adjusting for baseline maternal serum 25(OH)D levels, season of exposure, and skin color of the infant. Sun index for exposure in morning (before 10 am) and afternoon (10 am-3 pm) were also correlated to vitamin D status. Of 100 mother-infant pairs completing the study, 90 mothers had vitamin D deficiency (serum 25(OH)D exposure of infants to sunlight was 17 min per week, on 6% of body surface area. Vitamin D levels of 67 (67%) infants at 6 months were less than 12 ng/mL and another 23% had insufficient levels (12-20 ng/mL). Cumulative sun index correlated positively to infant's serum 25(OH)D level at 6 months of age (r= 0.461, Psunlight exposure, between 10 am and 3 pm, over 40% body area (infant clothed in diapers, in prone position) for at least 16 weeks, was estimated requirement to achieve sufficient vitamin D levels (>20 ng/mL) by 6 months of age. There is a significant positive correlation

  9. Sunlight exposure is important for preventing hip fractures in patients with Alzheimer's disease, Parkinson's disease, or stroke.

    Science.gov (United States)

    Iwamoto, J; Takeda, T; Matsumoto, H

    2012-04-01

    Hypovitaminosis D as a result of malnutrition or sunlight deprivation, increased bone resorption, low bone mineral density (BMD), or an increased risk of falls may contribute to an increased risk of hip fractures in patients with neurological diseases, including Alzheimer's disease, Parkinson's disease, and stroke. The purpose of this study was to clarify the efficacy of sunlight exposure for reducing the risk of hip fractures in patients with such neurological diseases. The English literature was searched using PubMed, and randomized controlled trials evaluating the efficacy of sunlight exposure for reducing the risk of hip fractures in patients with Alzheimer's disease, Parkinson's disease, and stroke were identified. The relative risk and the 95% confidence interval were calculated for individual randomized controlled trials, and a pooled data analysis (meta-analysis) was performed. Three randomized controlled trials were identified. Sunlight exposure improved hypovitaminosis D and increased the BMD. The relative risk (95% confidence interval) of hip fractures was 0.22 (0.05, 1.01) for Alzheimer's disease, 0.27 (0.08, 0.96) for Parkinson's disease, and 0.17 (0.02, 1.36) for stroke. The relative risk (95% confidence interval) calculated for the pooled data analysis was 0.23 (0.10, 0.56) (P = 0.0012), suggesting a significant risk reduction rate of 77%. The present meta-analysis added additional evidence indicating the efficacy of sunlight exposure for reducing the risk of hip fractures in patients with Alzheimer's disease, Parkinson's disease, and stroke. © 2011 John Wiley & Sons A/S.

  10. Is sunlight exposure a risk factor for age-related macular degeneration? A systematic review and meta-analysis.

    Science.gov (United States)

    Sui, Guo-Yuan; Liu, Guang-Cong; Liu, Guang-Ying; Gao, Yan-Yan; Deng, Yan; Wang, Wen-Ying; Tong, Shu-Hui; Wang, Lie

    2013-04-01

    Epidemiologists have recently investigated sunlight exposure as a risk factor for age-related macular degeneration (AMD), but there remains an ongoing dispute over this association due to insufficient evidence and unreliable data. To analyse comprehensively the epidemiological literature concerning the association between AMD and sunlight exposure. We systematically reviewed the epidemiological literature concerning the association between AMD and sunlight exposure. An electronic search was performed of PubMed, Web of Science and CNKI, which was supplemented by hand searching. The selection of studies, data abstraction and quality assessment were performed independently by three reviewers. After these steps, we performed a random-effects meta-analysis, followed by subgroup analysis and sensitivity analysis, including a random-effects meta-regression for study-specific covariates. Fourteen studies were identified. Twelve studies identified an increasing risk of AMD with greater sunlight exposure, six of which reported significant risks. The pooled OR was 1.379 (95% CI 1.091 to 1.745). The subgroup of non-population-based studies revealed a significant risk (OR 2.018, 1.248 to 3.265, p=0.004). We identified the gross domestic product (GDP) per capita (p=0.048), but not the latitude (p=0.21), as a factor that led to heterogeneity according to the meta-regression. The epidemiological literature published to date indicates that individuals with more sunlight exposure are at a significantly increased risk of AMD. The OR significantly decreased with increasing GDP per capita.

  11. Exposure time to sunlight for ultra violet light therapy

    Directory of Open Access Journals (Sweden)

    Srinivas C

    1991-01-01

    Full Text Available Exposure time to sunlight for photo or photochemotherapy is arbitrarily determined. This could lead to inadequate or over exposure. As a sequence to our initial pilot study on exposure time for PUVASOL, we have now developed a bar chart which could be used as a guide to achieve a more logical and uniform exposure time during different months. We plan to extend the study to different zones in India.

  12. Sunlight Exposure and Breast Density: A Population-Based Study

    Science.gov (United States)

    Wu, Sheng-Hui; So, Edwin; Lam, Tsz-ping; Woo, Jean; Yuen, PY; Qin, Ling; Ku, Susanna

    2013-01-01

    Purpose This study aims to assess the association of sunlight exposure with breast cancer risk, measured by the breast density assessed from Tabár's mammographic pattern in Chinese women. Methods A total of 676 premenopausal women were recruited to participate in this study, in which 650 completed a validated sunlight exposure questionnaire via telephone. The mammograms were classified according to Tabár's classification for parenchyma, and patterns IV & V and I, II & III indicated respectively high and low risk mammographic patterns for breast cancer. The odds ratios (OR) and 95% confidence intervals (CIs) for sun exposure-related variables were estimated using unconditional logistic regression with adjustment for potential confounders. Results Among 646 participants, women with high breast cancer risk (Tabár's patterns IV &V) had less hours spent in the sun than those with low risk (I, II & III) at any age stage. A higher level of sunlight exposure was associated with a significantly lower risk having high risk Tabár's pattern. Women aged 40 to 44 years who were in the highest tertile of lifetime total hours spent in the sun had a multi-adjusted OR of 0.41 (95% CI, 0.18-0.92; p for trend=0.03) compared with those in the lowest tertile (>2.19 hr/day vs. sunlight exposure is related to a lower risk of having high risk breast density pattern in premenopausal women. Our results also suggest the most relevant period of exposure is during earlier life. PMID:23843849

  13. Sunlight technologies for photochemical deactivation of organic pollutants in water

    Energy Technology Data Exchange (ETDEWEB)

    Acher, A.; Fischer, E.; Tornheim, R. [The Volcani Center, Inst. of Soils and Water, Bet Dagan (Israel); Manor, Y. [Sheba Medical Center, Central Virology Lab., Ramat Gan (Israel)

    1997-12-31

    Sensitized-photochemical oxidation methods aimed at use in water treatment technologies for deactivation of biotic (microorganisms) and/or of xenobiotic (pesticides) pollutants in water were developed using global solar radiation or concentrated sunlight (up to 250 suns). The solar global radiation was used either for detoxification of industrial waste water from a pesticide factory to allow their discharge into the urban sewer, or for disinfection of domestric effluents to be used in crop irrigation. The disinfection process was eventually carried out in an experimental pilot-scale plant, capable of disinfection up to 50 m{sup 3}/h of effluent supplied by an activated sludge sewage treatment plant located in Tel-Aviv area. The treated effluents did not show any regrowth of the microorganisms during 7 days. The solar concentrated radiation experiments performed using facilities of the Sun Tower of The Weizman Institute of Science, Rehovot. The concentrated sunlight was provided by different combination of several computer controlled heliostates, up to 8, that track the sun and focus the received sunlight onto the target situated on the roof of the sun-tower. The sunlight intensities measured on the target reached up to 200 kW/m{sup 2}. The experiments were performed either batch- or continuous-wise. The water-samples exposed to disinfection were the above effluent, filtered and supplemented with vaccine strain poliovirus or with different concentrations of an industrial potential pollutant (bromacil), MB 2 mg/L and two concentrations of dissolved oxygen (8.0 or 40.0 mg O{sub 2}/L). An exposure time of 2-3 seconds at 150 kW/m{sup 2} was decreased the microorganisms alive (counts) by five orders of magnitude. A comparison between the two above water treatment technologies is presented. (orig./SR)

  14. Novel materials and devices for sunlight concentrating systems

    Science.gov (United States)

    Hovel, H. J.

    1980-09-01

    An economic analysis of photovoltaic conversion under concentrated sunlight has been performed which demonstrates that solar cell efficiency, concentrator efficiency, and concentrator cost are the most important parameters in a concentrating photovoltaic system; solar cell cost is only of secondary importance. Six novel structures are described, including modified conventional Si cells Ga(1-x)Al(x)As/GaAs, interdigitated cells, vertical and horizontal multijunction cells and 'multicolor' devices.

  15. Effect of sunlight exposure on serum 25-hydroxyvitamin d concentration in women with vitamin d deficiency: using ambulatory lux meter and sunlight exposure questionnaire.

    Science.gov (United States)

    Lee, Sang-Hoon; Park, Soo-Jung; Kim, Kwang-Min; Lee, Duck-Joo; Kim, Woo-Jae; Park, Rae-Woong; Joo, Nam-Seok

    2012-11-01

    Vitamin D is an important factor in human health. Yet, vitamin D deficiency is very common. We aimed to confirm serum 25-hydroxyvitamin D (25OHD) concentration change after sunlight exposure and to elucidate the relationship between the amount of sunlight exposure and serum 25OHD level change by ambulatory lux meter and sunlight exposure questionnaire. Twenty healthy young women were enrolled. They were educated to obtain 20 minutes of sunlight exposure during weekdays from October to November, 2010, during which they were to wear an ambulatory lux meter on an arm. All subjects completed a one-week recall sunlight exposure questionnaire at the end of the study. Before and after sunlight exposure, serum 25OHD level was measured. Mean pre-exposure serum 25OHD concentration was 11.01 ng/mL. The mean change of pre- and post-exposure 25OHD level was -0.62 ng/mL, but it was not statistically significant. The mean personal sunlight exposure recorded by ambulatory lux meter, 292.6 lux/s, showed no significant relationship with average change of 25OHD and average weekly sunlight exposure score, 11.9, calculated by the sunlight exposure questionnaire. However, the mean change of serum 25OHD level and weekly sunlight exposure score showed significant negative correlation (r = -0.469, P = 0.037). Change of serum 25OHD concentration after four weeks of sunlight exposure was not statistically significant in women with vitamin D deficiency. However, serum 25OHD concentration change was significantly negatively correlated with the sunlight exposure score by the questionnaire.

  16. South African university student knowledge of eye protection against sunlight

    Directory of Open Access Journals (Sweden)

    O. A. Oduntan

    2009-12-01

    Full Text Available Exposure to sunlight has been associated with several ocular conditions such as cataract, age-related macular degeneration, and conjunctival neoplasm. Knowledge of protective modalities and good behavioural practice involving eye protection is essential to prevent adverse effects of sunlight. The purpose of this study was to establish knowledge amongst randomly selected university students in South Africa, of prevention modalities against the adverse effects of sunlight. A questionnaire relating to the knowledge of preventive modalities was completed by randomly selected students from four universities selected by convenience sampling.  Questionnaires completed by one thousand, eighthundred and thirty two (N =1832 subjects were analysed with descriptive statistics using Stata version 10.  The participants’ ages ranged from 17 to 55 years (mean = 21.03 ± 3.4 years.  They included 43.7% males and 56.3% females.  They were 68.3% Blacks, 20.0% Whites, 3.4% Indians and 7.4% Coloureds. Many (82.3% of them knew that excessive exposure to sunlight can adversely affect the eyes. Only 28.5% reported that they often wore sunglasses outdoors. Only 38.5% of the participants knew that not all spectacles or contact lenses could protect eyes from ultraviolet radiation. However, many, 87.7% and 69.5% respectively knew that sunglasses and spectacles could be specifically designed to block UVR from entering the eye. Just over half (52.7% knew that contact lenses can be specifically designed to block the UVR. Many, (68.4% agreed that wearing hats with brims could protect the eyes against harmful radiation from the sun and the majority, 95.8% agreed that there was a need for awareness campaigns about the effects of the sun on the eye and against excessive exposure. Female respondents had more knowledge of preventive modalities than the males.  Knowledge of preventive modalities among the respondents varied significantly with the type of questions and was

  17. Data Clustering

    Science.gov (United States)

    Wagstaff, Kiri L.

    2012-03-01

    On obtaining a new data set, the researcher is immediately faced with the challenge of obtaining a high-level understanding from the observations. What does a typical item look like? What are the dominant trends? How many distinct groups are included in the data set, and how is each one characterized? Which observable values are common, and which rarely occur? Which items stand out as anomalies or outliers from the rest of the data? This challenge is exacerbated by the steady growth in data set size [11] as new instruments push into new frontiers of parameter space, via improvements in temporal, spatial, and spectral resolution, or by the desire to "fuse" observations from different modalities and instruments into a larger-picture understanding of the same underlying phenomenon. Data clustering algorithms provide a variety of solutions for this task. They can generate summaries, locate outliers, compress data, identify dense or sparse regions of feature space, and build data models. It is useful to note up front that "clusters" in this context refer to groups of items within some descriptive feature space, not (necessarily) to "galaxy clusters" which are dense regions in physical space. The goal of this chapter is to survey a variety of data clustering methods, with an eye toward their applicability to astronomical data analysis. In addition to improving the individual researcher’s understanding of a given data set, clustering has led directly to scientific advances, such as the discovery of new subclasses of stars [14] and gamma-ray bursts (GRBs) [38]. All clustering algorithms seek to identify groups within a data set that reflect some observed, quantifiable structure. Clustering is traditionally an unsupervised approach to data analysis, in the sense that it operates without any direct guidance about which items should be assigned to which clusters. There has been a recent trend in the clustering literature toward supporting semisupervised or constrained

  18. Sunlight exposure and cutaneous human papillomavirus seroreactivity in basal cell and squamous cell carcinomas of the skin.

    Science.gov (United States)

    Iannacone, Michelle R; Wang, Wei; Stockwell, Heather G; O'Rourke, Kathleen; Giuliano, Anna R; Sondak, Vernon K; Messina, Jane L; Roetzheim, Richard G; Cherpelis, Basil S; Fenske, Neil A; Michael, Kristina M; Waterboer, Tim; Pawlita, Michael; Rollison, Dana E

    2012-08-01

    Ultraviolet radiation exposure may interact synergistically with cutaneous human papillomavirus (HPV) infection in the development of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin. To investigate differences in the risk of sunlight-associated BCC and SCC by cutaneous genus-specific HPV serostatus, a case-control study was conducted among 204 BCC and 156 SCC cases who were recruited from a university dermatology clinic and 297 controls who had no history of cancer and screened negative for current skin cancer. Logistic regression was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs) for the associations between measures of sunlight exposure and BCC/SCC, stratified by genus-specific HPV serostatus, with adjustment for age and sex. Sunburn due to cutaneous sensitivity to sunlight exposure (P = .006) and poor tanning ability (P = .003) were associated with a higher seroprevalence for genus beta HPV types. Poor or no tanning ability was more strongly associated with SCC among individuals who were seropositive for antibodies to cutaneous HPV types in genera alpha (OR, 15.60; 95% CI, 5.40-45.1; P = .01 for interaction) and beta (OR, 6.86; 95% CI, 3.68-12.80; P = .001 for interaction), compared with individuals who were seronegative for these HPV types. Seropositivity for HPV types in genera alpha or beta increased the risk of SCC associated with poor tanning ability.

  19. Randomized Control Trial Assessing Impact of Increased Sunlight Exposure versus Vitamin D Supplementation on Lipid Profile in Indian Vitamin D Deficient Men.

    Science.gov (United States)

    Patwardhan, Vivek G; Mughal, Zulf M; Padidela, Raja; Chiplonkar, Shashi A; Khadilkar, Vaman V; Khadilkar, Anuradha V

    2017-01-01

    Despite abundance of sunshine in India, Vitamin D deficiency is common and therefore there is an increasing trend toward taking Vitamin D supplements either as prescription medicine or as a nutritional supplement. Studies have suggested that duration of sun exposure may influence serum lipid profile. To study the effect of increased sunlight exposure versus Vitamin D supplementation on Vitamin D status and lipid profile in individuals with Vitamin D deficiency (25-hydroxyvitamin-D [25OHD] 50 nmol/L, n = 50) and intervention (sunlight exposure group" (n = 50, received at least 20 min sunlight exposure to forearms and face between 11 a.m. and 3 p.m. over and above their current exposure) or "cholecalciferol supplement group" (n = 50, received oral cholecalciferol 1000 IU/day). Significant increase in 25OHD concentrations was seen in both intervention groups (P sunlight exposure (P sunlight exposure significantly reduced TC, LDL-C, and HDL-C concentrations, and cholecalciferol supplementation increased TC and HDL-C concentrations.

  20. The (cost-effectiveness of an individually tailored long-term worksite health promotion programme on physical activity and nutrition: design of a pragmatic cluster randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Burdorf Alex

    2007-09-01

    Full Text Available Abstract Background Cardiovascular disease is the leading cause of disability and mortality in most Western countries. The prevalence of several risk factors, most notably low physical activity and poor nutrition, is very high. Therefore, lifestyle behaviour changes are of great importance. The worksite offers an efficient structure to reach large groups and to make use of a natural social network. This study investigates a worksite health promotion programme with individually tailored advice in physical activity and nutrition and individual counselling to increase compliance with lifestyle recommendations and sustainability of a healthy lifestyle. Methods/Design The study is a pragmatic cluster randomised controlled trial with the worksite as the unit of randomisation. All workers will receive a standard worksite health promotion program. Additionally, the intervention group will receive access to an individual Health Portal consisting of four critical features: a computer-tailored advice, a monitoring function, a personal coach, and opportunities to contact professionals at request. Participants are employees working for companies in the Netherlands, being literate enough to read and understand simple Internet-based messages in the Dutch language. A questionnaire to assess primary outcomes (compliance with national recommendations on physical activity and on fruit and vegetable intake will take place at baseline and after 12 and 24 months. This questionnaire also assesses secondary outcomes including fat intake, self-efficacy and self-perceived barriers on physical activity and fruit and vegetable intake. Other secondary outcomes, including a cardiovascular risk profile and physical fitness, will be measured at baseline and after 24 months. Apart from the effect evaluation, a process evaluation will be carried out to gain insight into participation and adherence to the worksite health promotion programme. A cost-effectiveness analysis and

  1. The Seasonality of Tuberculosis, Sunlight, Vitamin D, and Household Crowding

    Science.gov (United States)

    Wingfield, Tom; Schumacher, Samuel G.; Sandhu, Gurjinder; Tovar, Marco A.; Zevallos, Karine; Baldwin, Matthew R.; Montoya, Rosario; Ramos, Eric S.; Jongkaewwattana, Chulanee; Lewis, James J.; Gilman, Robert H.; Friedland, Jon S.; Evans, Carlton A.

    2014-01-01

    Background. Unlike other respiratory infections, tuberculosis diagnoses increase in summer. We performed an ecological analysis of this paradoxical seasonality in a Peruvian shantytown over 4 years. Methods. Tuberculosis symptom-onset and diagnosis dates were recorded for 852 patients. Their tuberculosis-exposed cohabitants were tested for tuberculosis infection with the tuberculin skin test (n = 1389) and QuantiFERON assay (n = 576) and vitamin D concentrations (n = 195) quantified from randomly selected cohabitants. Crowding was calculated for all tuberculosis-affected households and daily sunlight records obtained. Results. Fifty-seven percent of vitamin D measurements revealed deficiency (<50 nmol/L). Risk of deficiency was increased 2.0-fold by female sex (P < .001) and 1.4-fold by winter (P < .05). During the weeks following peak crowding and trough sunlight, there was a midwinter peak in vitamin D deficiency (P < .02). Peak vitamin D deficiency was followed 6 weeks later by a late-winter peak in tuberculin skin test positivity and 12 weeks after that by an early-summer peak in QuantiFERON positivity (both P < .04). Twelve weeks after peak QuantiFERON positivity, there was a midsummer peak in tuberculosis symptom onset (P < .05) followed after 3 weeks by a late-summer peak in tuberculosis diagnoses (P < .001). Conclusions. The intervals from midwinter peak crowding and trough sunlight to sequential peaks in vitamin D deficiency, tuberculosis infection, symptom onset, and diagnosis may explain the enigmatic late-summer peak in tuberculosis. PMID:24596279

  2. Sunlight and Skin Cancer: Lessons from the Immune System

    OpenAIRE

    Ullrich, Stephen E

    2007-01-01

    The ultraviolet (UV) radiation in sunlight induces skin cancer development. Skin cancer is the most common form of human neoplasia. Estimates suggest that in excess of 1.5 million new cases of skin cancer (www.cancer.org/statistics) will be diagnosed in the United States this year Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from sk...

  3. Sunlight and Skin Cancer: Lessons from the Immune System

    OpenAIRE

    Ullrich, Stephen E

    2007-01-01

    The ultraviolet (UV) radiation in sunlight induces skin cancer development. Skin cancer is the most common form of human neoplasia. Estimates suggest that in excess of 1.5 million new cases of skin cancer (www.cancer.org/statistics) will be diagnosed in the United States this year Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from sk...

  4. Effect of Sunlight Exposure on Bone Mineral Density in Children with Severe Disability.

    Science.gov (United States)

    Kanemura, Hideaki; Hatakeyama, Kazuo; Sano, Fumikazu; Yagasaki, Hideaki; Sugita, Kanji; Aihara, Masao

    2016-08-01

    The aim of this study was to determine the efficacy of sunlight exposure for increasing bone mineral density (BMD) in children with severe disability. The subjects were five children with severe disability, aged 6 to 8 years. BMD was measured at baseline and after 3, 6, 9, and 12 months of starting sunlight exposure. All caregivers of patients were instructed to create opportunities to stay outdoors. Daily sunlight exposure time was defined as hours of staying outdoors. Mean hours of sunbathing per day were calculated at baseline and after 3, 6, 9, and 12 months of starting sunlight exposure. Sunlight exposure tended to be longer after starting than before starting in all patients, but the difference was not significant (p = 0.052). Along with the increase in sunlight exposure, BMD increased significantly after the start of sunlight exposure in all patients (p sunlight exposure. No patients had bone fractures after the start of sunlight exposure. These results suggest that sunlight exposure increased BMD, and that this may reduce the risk of bone fracture in children with disability. Georg Thieme Verlag KG Stuttgart · New York.

  5. Use of sunlight to degrade oxytetracycline in marine aquaculture's waters.

    Science.gov (United States)

    Leal, J F; Esteves, V I; Santos, E B H

    2016-06-01

    Oxytracycline (OTC) is a broad spectrum antibiotic authorized for use in European aquaculture. Its photo-degradation has been widely studied in synthetic aqueous solutions, sometimes resorting to expensive methods and without proven effectiveness in natural waters. Thus, this work studied the possibility to apply the solar photo-degradation for removal of OTC from marine aquaculture's waters. For that, water samples were collected at different locals of the water treatment circuit, from two different aquaculture companies. Water samples were firstly characterized regarding to pH, salinity, total suspended solids (TSS), organic carbon and UV-Vis spectroscopic characteristics. Then, the samples were spiked with OTC and irradiated using simulated sunlight in order to evaluate the matrix effects on OTC photo-degradation. From kinetic results, the apparent quantum yields and the outdoor half-life times, at 40°N for midsummer and midwinter days were estimated by the first time for these conditions. For a midsummer day, at sea level, the outdoor half-life time predicted for OTC in these aquaculture's waters ranged between 21 and 25 min. Additionally, the pH and salinity effects on the OTC photo-degradation were evaluated and it has been shown that high pH values and the presence of sea salt increase the OTC photo-degradation rate in aquaculture's waters, compared to results in deionised water. The results are very promising to apply this low-cost methodology using the natural sunlight in aquaculture's waters to remove OTC.

  6. Decomposition of S-Nitrosothiols Induced by UV and Sunlight

    Directory of Open Access Journals (Sweden)

    Manoj M. Veleeparampil

    2009-01-01

    Full Text Available Photochemical release of nitric oxide (NO from the S-nitroso derivatives of glutathione, L-cysteine, N-acetyl-L-cysteine, L-cysteinemethylester, D,L-penicillamine, N-acetyl-D,L-penicillamine, and N-acetylcysteamine has been investigated at neutral and acidic pH. The release of NO from RSNO is one of the key reactions that could be utilized in photodynamic therapy. The UV-VIS and HPLC analyses have shown that under argon saturated conditions, disulfide (RSSR is the major product of UV as well as sunlight induced decomposition. While in aerated conditions, nitirite—the end product of the oxidation of NO—was also observed along with disulfide. The formation of thiyl radical as the intermediate was reconfirmed by laser flash photolysis. The initial rate of formation of NO was on the order of 10−10dm3mol−1s−1. The quantum yields of these reactions were in the range of 0.2–0.8. The high quantum yields observed in the photo induced release of NO from RSNO using both UV and sunlight demonstrate the potential application of these reactions in photodynamic therapy.

  7. Can Skin Exposure to Sunlight Prevent Liver Inflammation?

    Directory of Open Access Journals (Sweden)

    Shelley Gorman

    2015-05-01

    Full Text Available Liver inflammation contributes towards the pathology of non-alcoholic fatty liver disease (NAFLD. Here we discuss how skin exposure to sunlight may suppress liver inflammation and the severity of NAFLD. Following exposure to sunlight-derived ultraviolet radiation (UVR, the skin releases anti-inflammatory mediators such as vitamin D and nitric oxide. Animal modeling studies suggest that exposure to UVR can prevent the development of NAFLD. Association studies also support a negative link between circulating 25-hydroxyvitamin D and NAFLD incidence or severity. Clinical trials are in their infancy and are yet to demonstrate a clear beneficial effect of vitamin D supplementation. There are a number of potentially interdependent mechanisms whereby vitamin D could dampen liver inflammation, by inhibiting hepatocyte apoptosis and liver fibrosis, modulating the gut microbiome and through altered production and transport of bile acids. While there has been a focus on vitamin D, other mediators induced by sun exposure, such as nitric oxide may also play important roles in curtailing liver inflammation.

  8. Can skin exposure to sunlight prevent liver inflammation?

    Science.gov (United States)

    Gorman, Shelley; Black, Lucinda J; Feelisch, Martin; Hart, Prue H; Weller, Richard

    2015-05-05

    Liver inflammation contributes towards the pathology of non-alcoholic fatty liver disease (NAFLD). Here we discuss how skin exposure to sunlight may suppress liver inflammation and the severity of NAFLD. Following exposure to sunlight-derived ultraviolet radiation (UVR), the skin releases anti-inflammatory mediators such as vitamin D and nitric oxide. Animal modeling studies suggest that exposure to UVR can prevent the development of NAFLD. Association studies also support a negative link between circulating 25-hydroxyvitamin D and NAFLD incidence or severity. Clinical trials are in their infancy and are yet to demonstrate a clear beneficial effect of vitamin D supplementation. There are a number of potentially interdependent mechanisms whereby vitamin D could dampen liver inflammation, by inhibiting hepatocyte apoptosis and liver fibrosis, modulating the gut microbiome and through altered production and transport of bile acids. While there has been a focus on vitamin D, other mediators induced by sun exposure, such as nitric oxide may also play important roles in curtailing liver inflammation.

  9. The impact of sunlight on high-latitude equivalent currents

    CERN Document Server

    Laundal, K M; Østgaard, N; Reistad, J P; Haaland, S; Snekvik, K; Tenfjord, P; Ohtani, S; Milan, S E

    2016-01-01

    Ground magnetic field measurements can be mathematically related to an overhead ionospheric equivalent current. In this study we look in detail at how the global equivalent current, calculated using more than 30 years of SuperMAG magnetometer data, changes with sunlight conditions. The calculations are done using spherical harmonic analysis in quasi-dipole coordinates, a technique which leads to improved accuracy compared to previous studies. Sorting the data according to the location of the sunlight terminator and orientation of the interplanetary magnetic field (IMF), we find that the equivalent current resembles ionospheric convection patterns on the sunlit side of the terminator but not on the dark side. On the dark side, with southward IMF, the current is strongly dominated by a dawn cell and the current across the polar cap has a strong dawnward component. The contrast between the sunlit and dark side increases with increasing values of the $\\mathit{F}_{10.7}$ index, showing that increasing solar EUV fl...

  10. Development of an algorithm to predict serum vitamin D levels using a simple questionnaire based on sunlight exposure.

    Science.gov (United States)

    Vignali, Edda; Macchia, Enrico; Cetani, Filomena; Reggiardo, Giorgio; Cianferotti, Luisella; Saponaro, Federica; Marcocci, Claudio

    2017-01-01

    Sun exposure is the main determinant of vitamin D production. The aim of this study was to develop an algorithm to assess individual vitamin D status, independently of serum 25(OHD) measurement, using a simple questionnaire, mostly relying upon sunlight exposure, which might help select subjects requiring serum 25(OHD) measurement. Six hundred and twenty adult subjects living in a mountain village in Southern Italy, located at 954 m above the sea level and at a latitude of 40°50'11″76N, were asked to fill the questionnaire in two different periods of the year: August 2010 and March 2011. Seven predictors were considered: month of investigation, age, sex, BMI, average daily sunlight exposure, beach holidays in the past 12 months, and frequency of going outdoors. The statistical model assumes four classes of serum 25(OHD) concentrations: ≤10, 10-19.9, 20-29.9, and ≥30 ng/ml. The algorithm was developed using a two-step procedure. In Step 1, the linear regression equation was defined in 385 randomly selected subjects. In Step 2, the predictive ability of the regression model was tested in the remaining 235 subjects. Seasonality, daily sunlight exposure and beach holidays in the past 12 months accounted for 27.9, 13.5, and 6.4 % of the explained variance in predicting vitamin D status, respectively. The algorithm performed extremely well: 212 of 235 (90.2 %) subjects were assigned to the correct vitamin D status. In conclusion, our pilot study demonstrates that an algorithm to estimate the vitamin D status can be developed using a simple questionnaire based on sunlight exposure.

  11. The Irish DAFNE study protocol: a cluster randomised trial of group versus individual follow-up after structured education for type 1 diabetes.

    LENUS (Irish Health Repository)

    Dinneen, Seán F

    2009-01-01

    BACKGROUND: Structured education programmes for individuals with Type 1 diabetes have become a recognised means of delivering the knowledge and skills necessary for optimal self-management of the condition. The Dose Adjustment for Normal Eating (DAFNE) programme has been shown to improve biomedical (HbA(1c) and rates of severe hypoglycaemia) and psychosocial outcomes for up to 12 months following course delivery. The optimal way to support DAFNE graduates and maintain the benefits of the programme has not been established. We aimed to compare 2 different methods of follow-up of DAFNE graduates in a pragmatic clinical trial delivered in busy diabetes clinics on the island of Ireland. METHODS: Six participating centres were cluster randomised to deliver either group follow-up or a return to traditional one-to-one clinic visits. In the intervention arm group follow-up was delivered at 6 and 12 months post DAFNE training according to a curriculum developed for the study. In the control arm patients were seen individually in diabetes clinics as part of routine care. Study outcomes included HbA(1c) levels, self-reported rates of severe hypoglycaemia, body weight and measures of diabetes wellbeing and quality of life. These were measured at 6, 12 and 18 months after recruitment. Generalisability (external validity) was maximised by recruiting study participants from existing DAFNE waiting lists in each centre, by using broad inclusion criteria (including HbA(1c) values less than 13 percent with no lower limit) and by using existing clinic staff to deliver the training and follow-up. Internal validity and treatment fidelity were maximised by quality assuring the training of all DAFNE educators, by external peer review of the group follow-up sessions and by striving for full attendance at follow-up visits. Assays of HbA(1c) were undertaken in a central laboratory. DISCUSSION: This pragmatic clinical trial evaluating group follow-up after a structured education programme has

  12. The Irish DAFNE Study Protocol: A cluster randomised trial of group versus individual follow-up after structured education for Type 1 diabetes

    Directory of Open Access Journals (Sweden)

    Newell John

    2009-09-01

    Full Text Available Abstract Background Structured education programmes for individuals with Type 1 diabetes have become a recognised means of delivering the knowledge and skills necessary for optimal self-management of the condition. The Dose Adjustment for Normal Eating (DAFNE programme has been shown to improve biomedical (HbA1c and rates of severe hypoglycaemia and psychosocial outcomes for up to 12 months following course delivery. The optimal way to support DAFNE graduates and maintain the benefits of the programme has not been established. We aimed to compare 2 different methods of follow-up of DAFNE graduates in a pragmatic clinical trial delivered in busy diabetes clinics on the island of Ireland. Methods Six participating centres were cluster randomised to deliver either group follow-up or a return to traditional one-to-one clinic visits. In the intervention arm group follow-up was delivered at 6 and 12 months post DAFNE training according to a curriculum developed for the study. In the control arm patients were seen individually in diabetes clinics as part of routine care. Study outcomes included HbA1c levels, self-reported rates of severe hypoglycaemia, body weight and measures of diabetes wellbeing and quality of life. These were measured at 6, 12 and 18 months after recruitment. Generalisability (external validity was maximised by recruiting study participants from existing DAFNE waiting lists in each centre, by using broad inclusion criteria (including HbA1c values less than 13 percent with no lower limit and by using existing clinic staff to deliver the training and follow-up. Internal validity and treatment fidelity were maximised by quality assuring the training of all DAFNE educators, by external peer review of the group follow-up sessions and by striving for full attendance at follow-up visits. Assays of HbA1c were undertaken in a central laboratory. Discussion This pragmatic clinical trial evaluating group follow-up after a structured education

  13. Cluster Correspondence Analysis

    NARCIS (Netherlands)

    M. van de Velden (Michel); A. Iodice D' Enza; F. Palumbo

    2014-01-01

    markdownabstract__Abstract__ A new method is proposed that combines dimension reduction and cluster analysis for categorical data. A least-squares objective function is formulated that approximates the cluster by variables cross-tabulation. Individual observations are assigned to clusters

  14. A novel solar cell fabricated with spiral photo-electrode for capturing sunlight 3-dimensionally

    Institute of Scientific and Technical Information of China (English)

    LIU Yong; SHEN Hui; DENG Youjun

    2006-01-01

    A novel solar cell fabricated with spiral photo-electrode for capturing sunlight 3-dimensionally (3D-cell) is proposed in this paper. We studied its performance both in solar simulator and in nature sunlight. Spiral photo-electrode of 3D-cell can receive sunlight from all directions and therefore can track the sun passively. And it is much insensitive to solar azimuth angle and shade. In addition, it increases the area to obtain scattered sunlight and reflected light. Compared with the dye-sensitized solar cells using sandwich structure, it would be more advantageous in the sealing technique.

  15. Sunlight-induced carbon dioxide emissions from inland waters

    Science.gov (United States)

    Koehler, Birgit; Landelius, Tomas; Weyhenmeyer, Gesa A.; Machida, Nanako; Tranvik, Lars J.

    2014-07-01

    The emissions of carbon dioxide (CO2) from inland waters are substantial on a global scale. Yet the fundamental question remains open which proportion of these CO2 emissions is induced by sunlight via photochemical mineralization of dissolved organic carbon (DOC), rather than by microbial respiration during DOC decomposition. Also, it is unknown on larger spatial and temporal scales how photochemical mineralization compares to other C fluxes in the inland water C cycle. We combined field and laboratory data with atmospheric radiative transfer modeling to parameterize a photochemical rate model for each day of the year 2009, for 1086 lakes situated between latitudes from 55°N to 69°N in Sweden. The sunlight-induced production of dissolved inorganic carbon (DIC) averaged 3.8 ± 0.04 g C m-2 yr-1, which is a flux comparable in size to the organic carbon burial in the lake sediments. Countrywide, 151 ± 1 kt C yr-1 was produced by photochemical mineralization, corresponding to about 12% of total annual mean CO2 emissions from Swedish lakes. With a median depth of 3.2 m, the lakes were generally deep enough that incoming, photochemically active photons were absorbed in the water column. This resulted in a linear positive relationship between DIC photoproduction and the incoming photon flux, which corresponds to the absorbed photons. Therefore, the slope of the regression line represents the wavelength- and depth-integrated apparent quantum yield of DIC photoproduction. We used this relationship to obtain a first estimate of DIC photoproduction in lakes and reservoirs worldwide. Global DIC photoproduction amounted to 13 and 35 Mt C yr-1 under overcast and clear sky, respectively. Consequently, these directly sunlight-induced CO2 emissions contribute up to about one tenth to the global CO2 emissions from lakes and reservoirs, corroborating that microbial respiration contributes a substantially larger share than formerly thought, and generate annual C fluxes similar in

  16. Cancer Clusters

    Science.gov (United States)

    ... Kidney (Renal Cell) Cancer Leukemia Liver Cancer Lung Cancer Lymphoma Pancreatic Cancer Prostate Cancer Skin Cancer Thyroid Cancer Uterine Cancer ... Myths and Misconceptions Diet Hormones Immunosuppression Infectious Agents Obesity Radiation Sunlight Tobacco Genetics NCI Cancer Genetics Services ...

  17. Asteroid thermal modeling in the presence of reflected sunlight

    Science.gov (United States)

    Myhrvold, Nathan

    2016-10-01

    This study addresses thermal modeling of asteroids with a new derivation of the Near Earth Asteroid Thermal (NEATM) model which correctly accounts for the presence of reflected sunlight in short wave IR bands. Kirchhoff's law of thermal radiation applies to this case and has important implications. New insight is provided into the ???? parameter in the NEATM model and it is extended to thermal models besides NEATM. The role of surface material properties on ???? is examined using laboratory spectra of meteorites and other asteroid compositional proxies; the common assumption that emissivity ????=0.9 in asteroid thermal models may not be justified and can lead to misestimating physical parameters. In addition, indeterminacy in thermal modeling can limit its ability to uniquely determine temperature and other physical properties. A new curve-fitting approach allows thermal modeling to be done independently of visible-band observational parameters, such as the absolute magnitude ????.

  18. Spectral analysis of red scattered sunlight at sunrise

    CERN Document Server

    Zagury, F; Zagury, Frederic; Fujii, Mitsugu

    2003-01-01

    We analyze and fit visible spectra of a red horizon at sunrise. The shape of the spectra consist of a blue continuum followed by a red bump. The reddest spectra are well fitted by the product of a spectrum of extinguished sunlight (Rayleigh extinction + ozone absorption) and 1/lambda^4. The former is essentially the radiation field in the outer atmosphere, at the scattering volume location; the latter corresponds to Rayleigh scattering by the gas. Moving to higher altitudes, a second component, corresponding to the spectrum of a blue sky, must be added. The spectra we have obtained are similar to spectra of red nebulae, suggesting there may be other explanations than an emission process to the red color of some nebulae.

  19. Sustainable sunlight to biogas is via marginal organics.

    Science.gov (United States)

    Shilton, Andy; Guieysse, Benoit

    2010-06-01

    Although biogas production from algae offers higher sunlight to biomass energy conversion efficiencies its production costs simply cannot compete with terrestrial plants. Unfortunately terrestrial plant cropping for biogas production is, in its own right, neither particularly sustainable nor profitable and its ongoing application is only driven by energy security concerns resulting in taxpayer subsidies. By comparison, scavenging the organic energy residual/wastes from food production offers a far more profitable and sustainable proposition and has an energy potential that dwarfs anything biogas production from dedicated energy crops can realistically offer. Thus researchers wanting to assist the development of sustainable biogas systems with viable process economics should forget about terrestrial and algal energy cropping and focus on the realm of scavengers.

  20. Circadian clocks optimally adapt to sunlight for reliable synchronization

    CERN Document Server

    Hasegawa, Yoshihiko

    2014-01-01

    Circadian oscillation provides selection advantages through synchronization to the daylight cycle. However, a reliable clock must be designed through two conflicting properties: entrainability to properly respond to external stimuli such as sunlight, and regularity to oscillate with a precise period. These two aspects do not easily coexist because better entrainability favors higher sensitivity, which may sacrifice the regularity. To investigate conditions for satisfying the two properties, we analytically calculated the optimal phase-response curve with a variational method. Our result indicates an existence of a dead zone, i.e., a time during which external stimuli neither advance nor delay the clock. This result is independent of model details and a dead zone appears only when the input stimuli obey the time course of actual insolation. Our calculation demonstrates that every circadian clock with a dead zone is optimally adapted to the daylight cycle. Our result also explains the lack of a dead zone in osc...

  1. Persistence of Bacteroides ovatus under simulated sunlight irradiation

    KAUST Repository

    Dong, Shengkun

    2014-07-04

    Background: Bacteroides ovatus, a member of the genus Bacteroides, is considered for use in molecular-based methods as a general fecal indicator. However, knowledge on its fate and persistence after a fecal contamination event remains limited. In this study, the persistence of B. ovatus was evaluated under simulated sunlight exposure and in conditions similar to freshwater and seawater. By combining propidium monoazide (PMA) treatment and quantitative polymerase chain reaction (qPCR) detection, the decay rates of B. ovatus were determined in the presence and absence of exogenous photosensitizers and in salinity up to 39.5 parts per thousand at 27°C. Results: UVB was found to be important for B. ovatus decay, averaging a 4 log10 of decay over 6 h of exposure without the presence of extracellular photosensitizers. The addition of NaNO2, an exogenous sensitizer producing hydroxyl radicals, did not significantly change the decay rate of B. ovatus in both low and high salinity water, while the exogenous sensitizer algae organic matter (AOM) slowed down the decay of B. ovatus in low salinity water. At seawater salinity, the decay rate of B. ovatus was slower than that in low salinity water, except when both NaNO2 and AOM were present. Conclusion: The results of laboratory experiments suggest that if B. ovatus is released into either freshwater or seawater environment in the evening, 50% of it may be intact by the next morning; if it is released at noon, only 50% may be intact after a mere 5 min of full spectrum irradiation on a clear day. This study provides a mechanistic understanding to some of the important environmental relevant factors that influenced the inactivation kinetics of B. ovatus in the presence of sunlight irradiation, and would facilitate the use of B. ovatus to indicate the occurrence of fecal contamination.

  2. Sunlight Exposure, Pigmentation, and Incident Age-Related Macular Degeneration

    Science.gov (United States)

    Klein, Barbara E. K.; Howard, Kerri P.; Iyengar, Sudha K.; Sivakumaran, Theru A.; Meyers, Kristin J.; Cruickshanks, Karen J.; Klein, Ronald

    2014-01-01

    Purpose. Examine potential effects of sunlight exposure, hair color, eye color, and selected gene single-nucleotide polymorphisms (SNPs) on incidence of AMD. Methods. Subjects participated in up to five examinations over a 20-year period. Eye color, self-reported hair color as a teenager, and sunlight exposure were ascertained at the baseline examination. Presence and severity of AMD and its lesions were determined via fundus photographs. Genetic data were available on a subset of participants. The SNPs CFH Y402H rs1061170 and ARMS2 A69S rs10490924 were used to analyze genetic risk of AMD; OCA2 rs4778241 and HERC2 rs12913832 represented genetic determinants of eye color. Results. Incidence of early AMD was higher in blond/red-haired persons compared with brown/black-haired persons (hazard ratio [HR] 1.25, P = 0.02) and in persons with high sun exposure in their thirties (HR 1.41, P = 0.02). However, neither was significant after adjustment for multiple comparisons. Eye (HR 1.36, P = 0.006) and hair color (HR 1.42, P = 0.003) were associated with incidence of any retinal pigmentary abnormalities (RPAs). Both remained significant after adjustment for multiple comparisons. Neither presence of alleles for light-colored eyes nor those associated with high risk of late AMD altered the association of eye or hair color with early AMD. None of the characteristics studied were significantly associated with late AMD. Conclusions. Modest associations of eye color, hair color, and HERC2 genotype with any RPAs were found. Genes for AMD did not affect these associations. Eye color phenotype was more strongly associated with outcomes than HERC2 or OCA2 genotype. PMID:25125603

  3. Sunlight exposure, pigmentation, and incident age-related macular degeneration.

    Science.gov (United States)

    Klein, Barbara E K; Howard, Kerri P; Iyengar, Sudha K; Sivakumaran, Theru A; Meyers, Kristin J; Cruickshanks, Karen J; Klein, Ronald

    2014-08-14

    Examine potential effects of sunlight exposure, hair color, eye color, and selected gene single-nucleotide polymorphisms (SNPs) on incidence of AMD. Subjects participated in up to five examinations over a 20-year period. Eye color, self-reported hair color as a teenager, and sunlight exposure were ascertained at the baseline examination. Presence and severity of AMD and its lesions were determined via fundus photographs. Genetic data were available on a subset of participants. The SNPs CFH Y402H rs1061170 and ARMS2 A69S rs10490924 were used to analyze genetic risk of AMD; OCA2 rs4778241 and HERC2 rs12913832 represented genetic determinants of eye color. Incidence of early AMD was higher in blond/red-haired persons compared with brown/black-haired persons (hazard ratio [HR] 1.25, P = 0.02) and in persons with high sun exposure in their thirties (HR 1.41, P = 0.02). However, neither was significant after adjustment for multiple comparisons. Eye (HR 1.36, P = 0.006) and hair color (HR 1.42, P = 0.003) were associated with incidence of any retinal pigmentary abnormalities (RPAs). Both remained significant after adjustment for multiple comparisons. Neither presence of alleles for light-colored eyes nor those associated with high risk of late AMD altered the association of eye or hair color with early AMD. None of the characteristics studied were significantly associated with late AMD. Modest associations of eye color, hair color, and HERC2 genotype with any RPAs were found. Genes for AMD did not affect these associations. Eye color phenotype was more strongly associated with outcomes than HERC2 or OCA2 genotype. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

  4. Practice nursed-based, individual and video-assisted patient education in oral anticoagulation--protocol of a cluster-randomized controlled trial.

    Science.gov (United States)

    Hua, Thanh Duc; Vormfelde, Stefan Viktor; Abu Abed, Manar; Schneider-Rudt, Hannelore; Sobotta, Petra; Friede, Tim; Chenot, Jean-François

    2011-04-10

    Managing oral anticoagulant treatment (OAT) is a challenge for patients and primary care providers. It requires a high level of patient knowledge and adherence. Studies have shown that insufficient adherence and a low level of patient knowledge about OAT are primary causes for complications. This trial is the first to evaluate the long-term effects of a complex practice nurse-based patient education program in comparison to a patient brochure only. This trial will be a cluster-randomized controlled trial in 22 general practices (GPs) recruiting 360 patients with OAT. GPs will be randomized into an intervention group or a control group. A baseline questionnaire will assess pre-existing knowledge about OAT. The patients in the intervention group will be educated by a complex education program which consists of a video, a brochure and individual training by a practice nurse. The video gives information about OAT, nutrition, and instructions about how to manage critical situations. The brochure repeats the content of the video. After 4 to 6 weeks, the intervention will be recapitulated. The control group will receive the brochure only. After 6 months, questionnaires will be used in both groups to assess patient knowledge about OAT as well as patients' subjective feelings of safety. Separately, we will evaluate patient records, looking for documented complications and the time spent in the therapeutic range. This trial will start in January 2011. This trial will evaluate the long-term effectiveness of a video-assisted education program on patients with OAT in comparison to a patient information brochure. Most previous studies have evaluated knowledge directly after an educational intervention. Our trial will look for long-term differences in basic knowledge of OAT. We expect that our complex patient education program effectively increases long-term basic knowledge about OAT. Although the population of our study is too small to observe differences in adverse effects, we

  5. Practice nursed-based, individual and video-assisted patient education in oral anticoagulation - Protocol of a cluster-randomized controlled trial

    Directory of Open Access Journals (Sweden)

    Friede Tim

    2011-04-01

    Full Text Available Abstract Background Managing oral anticoagulant treatment (OAT is a challenge for patients and primary care providers. It requires a high level of patient knowledge and adherence. Studies have shown that insufficient adherence and a low level of patient knowledge about OAT are primary causes for complications. This trial is the first to evaluate the long-term effects of a complex practice nurse-based patient education program in comparison to a patient brochure only. Methods and design This trial will be a cluster-randomized controlled trial in 22 general practices (GPs recruiting 360 patients with OAT. GPs will be randomized into an intervention group or a control group. A baseline questionnaire will assess pre-existing knowledge about OAT. The patients in the intervention group will be educated by a complex education program which consists of a video, a brochure and individual training by a practice nurse. The video gives information about OAT, nutrition, and instructions about how to manage critical situations. The brochure repeats the content of the video. After 4 to 6 weeks, the intervention will be recapitulated. The control group will receive the brochure only. After 6 months, questionnaires will be used in both groups to assess patient knowledge about OAT as well as patients' subjective feelings of safety. Separately, we will evaluate patient records, looking for documented complications and the time spent in the therapeutic range. Discussion This trial will start in January 2011. This trial will evaluate the long-term effectiveness of a video-assisted education program on patients with OAT in comparison to a patient information brochure. Most previous studies have evaluated knowledge directly after an educational intervention. Our trial will look for long-term differences in basic knowledge of OAT. We expect that our complex patient education program effectively increases long-term basic knowledge about OAT. Although the population of

  6. Grape cluster microclimate influences the aroma composition of Sauvignon blanc wine.

    Science.gov (United States)

    Martin, Damian; Grose, Claire; Fedrizzi, Bruno; Stuart, Lily; Albright, Abby; McLachlan, Andrew

    2016-11-01

    New Zealand Sauvignon blanc (SB) wines are characterised by a distinctive combination of tropical-fruity and green-herbaceous aromatic compounds. The influence of sunlight exposure of grape clusters on juice and wine composition was investigated, with the aim of manipulating aromatic compounds in SB wine. In the absence of basal leaf removal SB clusters naturally exposed to sunlight were riper than shaded clusters, evidenced by higher total soluble solids (TSS) and proline, and lower malic acid, 3-isobutyl-2-methoxypyrazine (IBMP) and arginine. Volatile thiols in wines did not differ between shaded and exposed clusters. At equivalent TSS, cluster exposure had little or no effect on malic acid concentration. Conversely, wine from shaded clusters had almost double the IBMP concentration of wine from exposed clusters at equivalent TSS. The effects on SB juice and wine composition of natural variations in cluster microclimate are not comparable with the effects of cluster exposure created through leaf removal.

  7. Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis

    NARCIS (Netherlands)

    D'hooghe, M. B.; Haentjens, P.; Nagels, G.; Garmyn, M.; De Keyser, J.

    2012-01-01

    Background: Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS). Objective: We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS. Methods: We conducted a survey among persons with MS, registered by the Flemish MS

  8. Amelioration of osteoporosis and hypovitaminosis D by sunlight exposure in Parkinson's disease.

    Science.gov (United States)

    Sato, Yoshihiro; Iwamoto, Jun; Honda, Yoshiaki

    2011-01-01

    A high incidence of fractures, particularly of the hip, represents an important problem in patients with Parkinson's disease (PD), who are prone to falls and have osteoporosis. We previously showed that 25-hydroxyvitamin D (25-OHD) deficiency due to sunlight deprivation with compensatory hyperparathyroidism causes reduced bone mineral density (BMD) in elderly patients with PD. The present study was undertaken to address the possibility that sunlight exposure may maintain BMD and reduce the incidence of hip fracture in elderly patients with PD. In a prospective study, PD patients were assigned to regular sunlight exposure (n=162) or usual lifestyle (n=162), and followed for 2 years. BMD of the second metacarpal bone was measured using a computed X-ray densitometer. Incidence of hip fracture in the two patient groups during the 2 year follow-up period was assessed. At baseline, patients of both groups showed vitamin D deficiency due to sunlight deprivation with compensatory hyperparathyroidism. The exposed group patients were exposed to sunlight (3231 min/year). BMD increased by 3.8% in the sunlight-exposed group and decreased by 2.6% in the usual lifestyle group (psunlight-exposed group. Eleven patients sustained hip fracture in the normal lifestyle group, and 3 fractures occurred among the sunlight-exposed group (p=.03; odds ratio=2.4). Sunlight exposure can increase the BMD of vitamin D deficient bone by increasing 25-OHD concentration and leads to the prevention of hip fracture. © 2010 Elsevier Ltd. All rights reserved.

  9. Does sunlight exposure improve survival in patients with non-small cell lung cancer?

    Science.gov (United States)

    Mutlu, Hasan; Buyukcelik, Abdullah; Aksahin, Arzu; Kibar, Mustafa; Cihan, Yasemin Benderli; Kaya, Eser; Seyrek, Ertugrul; Yavuz, Sinan; Erden, Abdulsamet; Calikusu, Zuleyha; Aslan, Tuncay; Akca, Zeki

    2013-01-01

    Some epidemiological studies reported that sunlight exposure and highvitamin D levels may decrease the morbidity and mortality related to cancer. We aimed to evaluate whether sunlight exposure has an impact on survival in patients with non small cell lung cancer. A total of 546 patients with NSCLC from two different regions (Kayseri and Adana) differing according to sunlight exposure were analysed retrospectively. The median overall survival (OS) rates were 11. 6 (CI: 9.50-13.6) and 15.6 months (CI: 12.4-18.8) for Kayseri and Adana, respectively, in all patients (p=0.880). There were no differences between groups in terms of OS. While there is strong evidence regarding inverse relationship between cancer incidence and sunlight exposure, it is still controversial whether sunlight exposure is a good prognostic factor for survival in patients with lung cancer.

  10. Sunlight Exposure, Work Hours, Caffeine Consumption, and Sleep Duration in the Naval Environment.

    Science.gov (United States)

    Shattuck, Nita L; Matsangas, Panagiotis

    2017-06-01

    Sailors in the U.S. Navy are habitual shiftworkers, often experiencing circadian misalignment due to their irregular work/rest schedules. This study assessed the effect of sunlight exposure, work hours, and caffeinated beverage consumption on the daily sleep duration of crewmembers of a U.S. Navy ship during a 2-wk underway period. Working in an artificially lit area with no access to sunlight during work hours, U.S. Navy crew members (N = 91) used daily logs to report their daily activity, caffeinated beverage consumption, and exposure to sunlight while off-duty; sleep was assessed by wrist-worn actigraphy. Hours of sunlight exposure, work duration, and the amount of coffee/tea/soft drinks were statistically significant predictors of sleep duration. On average, crewmembers who reported more than one half-hour of sunlight each day slept on average ∼40 min (10%) less than their peers working the same shifts who received less than one half-hour of sunlight (on average 6.05 ± 0.90 h vs. 6.71 ± 0.91 h, respectively). Exposure to sunlight, work hours, and consumption of caffeinated beverages are important factors when planning watchstanding schedules at sea. Even though further research is needed, our results suggest that even brief exposure to sunlight may contribute to circadian misalignment that negatively affects sleep in the operational environment. Educating crewmembers about sleep hygiene, especially the important roles played by sunlight and caffeine, could potentially improve the sleep and fatigue levels of this population of maritime shiftworkers.Shattuck NL, Matsangas P. Sunlight exposure, work hours, caffeine consumption, and sleep duration in the naval environment. Aerosp Med Hum Perform. 2017; 88(6):579-585.

  11. High spacecraft potentials on ISEE-1 in sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Whipple, E.C.; Olsen, R.C.

    1987-01-01

    Data from the two electric-field experiments and from the plasma-composition experiment on ISEE-1 show that the spacecraft charged to close to -70 V in sunlight at about 0700 UT on March 17, 1978. Data from the electron-spectrometer experiment show that there was a potential barrier of some -10 to -20 V about the spacecraft during this event. The potential barrier was effective in turning back emitted photoelectrons to the spacecraft. Potential barriers can be formed by differential charging on the spacecraft or by the presence of space charge. The stringent electrostatic cleanliness specifications imposed on ISEE made by the presence of differential charging seem unlikely, if these precautions were effective. Modeling of this event to determine if the barrier was produced by the presence of space charge, suggested that this could not explain the observed barrier. The angular shape of the distribution could be successfully modeled as a product of differential charging on the solar arrays. This implies that the conductive coating was not completely effective in preventing differential charging, and that differential charging did occur.

  12. Sunlight assisted photodegradation by tin oxide quantum dots

    Science.gov (United States)

    Shajira, P. S.; Prabhu, V. Ganeshchandra; Bushiri, M. Junaid

    2015-12-01

    Rutile phase of SnO2 quantum dots of average size of 2.5 nm were synthesized at a growth temperature of 70 °C and characterized with XRD, TEM, FTIR and Raman analysis. The effective strain within the lattice of SnO2 quantum dots was calculated by Williamson-Hall method. The broad peaks in XRD as well as Raman spectra and the presence of Raman bands at 569 and 432 cm-1 are due to lower crystallinity of nanoparticles. The optical band gap of SnO2 quantum dots was increased to 3.75 eV attributed to the quantum size effect. SnO2 quantum dots were annealed in air atmosphere and the crystallite size of the particles increased with annealing temperature. Sunlight assisted photodegration property of SnO2 quantum dots was investigated with vanillin as a model system and it shows the photodegradation efficiency of 87%. The photoluminescence and photodegradation efficiency of nanocrystallite SnO2 decreases with increase of crystallite size contributed to the reduction in population of defects and surface area.

  13. Occupational Sunlight Exposure and Risk of Renal Cell Carcinoma

    Science.gov (United States)

    Karami, Sara; Boffetta, Paolo; Stewart, Patricia; Rothman, Nathaniel; Hunting, Katherine L.; Dosemeci, Mustafa; Berndt, Sonja I.; Brennan, Paul; Chow, Wong-Ho; Moore, Lee E.; Zaridze, David; Mukeria, Anush; Janout, Vladimir; Kollarova, Helena; Bencko, Vladimir; Holcatova, Ivana; Navritalova, Marie; Szeszenia-Dabrowska, Neonila; Mates, Dana; Gromiec, Jan P.

    2010-01-01

    Background Recent findings indicate that vitamin D obtained from ultraviolet (UV) exposure may reduce the risk of a number of different cancers. Vitamin D is metabolized to its active form within the kidney, the major organ for vitamin D metabolism and activity. Since both the incidence of renal cell cancer and prevalence of vitamin D deficiency have increased over the past few decades, this study sought to explore whether occupational UV exposure was associated with renal cell carcinoma (RCC) risk. Methods A hospital-based case-control study of 1,097 RCC cases and 1,476 controls was conducted in four Central and Eastern European countries. Demographic and occupational information was collected to examine the association between occupational UV exposure and RCC risk. Results A significant (24%-38%) reduction in RCC risk was observed with increasing occupational UV exposure among male participants. No association between UV exposure and RCC risk was observed among female participants. When analyses were stratified by latitude as another estimate of sunlight intensity, a stronger (71%-73%) reduction in RCC risk was observed between UV exposure and cancer risk among males residing at the highest latitudes. Conclusion The results of this study suggest that among males there is an inverse association between occupational UV exposure and renal cancer risk. Replication studies are warranted to confirm these results. PMID:20213683

  14. Sunlight and skin cancer: lessons from the immune system.

    Science.gov (United States)

    Ullrich, Stephen E

    2007-08-01

    The ultraviolet (UV) radiation in sunlight induces skin cancer development. Skin cancer is the most common form of human neoplasia. Estimates suggest that in excess of 1.5 million new cases of skin cancer (www.cancer.org/statistics) will be diagnosed in the United States this year. Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer, and the cost of treating skin cancer in the United States (both melanoma and non-melanoma skin cancer) is estimated to be in excess of $2.9 billion a year. In addition to causing skin cancer, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. Recent studies in my laboratory have focused on understanding the initial molecular events that induce immune suppression. We made two novel observations: first UV-induced keratinocyte-derived platelet activating factor plays a role in the induction of immune suppression. Second, cis-urocanic acid, a skin-derived immunosuppressive compound mediates immune suppression by binding to serotonin receptors on target cells. Recent findings suggest that blocking the binding of these compounds to their receptors not only inhibits UV-induced immune suppression but it also interferes with skin cancer induction.

  15. Photocatalytic Hydrogen Production by Direct Sunlight: A Laboratory Experiment

    Science.gov (United States)

    Koca, Atif; Sahin, Musa

    2003-11-01

    The demand for hydrogen will increase within the next decades as a result of the necessity to produce clean and environmentally and economically accepted fuels from natural and renewable energy resources. In principle, hydrogen has the potential to play an important role in future energy systems because of the diversity of its applications, the variety of ways in which it can be stored, its general environmental advantages, and especially because of the possibility of producing hydrogen by splitting water using photocatalysts and solar energy. Methods and techniques of photocatalytic reactions are covered in some detail in many undergraduate chemistry programs. However, many times in instructional settings, little attention is given to how it is used for the production of hydrogen. In the present investigation a photocatalytic hydrogen production experiment suitable for use in undergraduate chemistry laboratories is described. The experiment can be used to introduce students to the concept of a renewable and sustainable hydrogen energy system of the future, as well as its production techniques, and to demonstrate the use of a CdS/ZnS photocatalyst system for photocatalytic hydrogen production from direct sunlight.

  16. The Effect of Sunlight in Parenchyma Pith Cells Diameter of Manihot esculenta

    Science.gov (United States)

    Susanti, D.; Aziz, D. N.; Astuti, W.; Nuraeni, E.

    2017-03-01

    Sunlight is one of the factors that effect on the grow of a plant. Manihot esculenta is one of the plants that easily found in Indonesia because its role as staple food. The aim of this research is to know the correlation between sunlight the grow of parenchyma pith cells diameter of Manihot esculenta. Independent variable in this research is sunlight, and dependent variable is the parenchyma pith cells diameter of Manihot esculenta. Data was collected is in qualitative and quantitative form. Qualitative data gotten gained by morphology observation. The parenchyma pith cells of Manihot esculenta that is affected by sunlight in 1310 x 10 Lux, morphologically has hexagon, cell walls thick, solid state, and regular composition. Meanwhile, the parenchyma pith cells that has less sunlight (363 x 10 Lux) has a hexagon shape, thin cell walls thin, soft state, and irregular composition. Qualitative data suported by quantitative data. The size of parenchyma pith cells diameter that is affected by sunlight in 1310 x 10 Lux 96,4 µm. While, the stem parenchyma pith cells diameter empulur that has less sunlight (363 x 10 Lux) is 129,8 µm.

  17. Formation of DNA strand breaks in peripheral lymphocytes of rats after exposure to natural sunlight.

    Science.gov (United States)

    Rodrigues-Junior, Dorival Mendes; Melo, Ana Amélia de Carvalho; da Silva, Benedito Borges; Lopes-Costa, Pedro Vitor

    2012-04-01

    This paper aims to evaluate the genotoxicity in peripheral blood lymphocytes of rats after exposure to sunlight at different time points of day in a tropical region of Brazil (5 degrees S, 42 degrees W). Thirty Wistar-Hannover rats, three months old, were randomly divided into three groups of 10 animals each: Group I [control, without exposure to ultraviolet (UV) radiation], Group II (exposed to sunlight during 08:00 a.m. to 10:00 a.m.), and Group III (exposed to sunlight during 10:00 a.m. to 12:00 a.m.). After a week of exposure, peripheral blood samples were taken from the tail of these animals to prepare smears on two slides per animal. In 24 h after exposure to sunlight in Group III, a new collection was obtained to observe the repair activity. The alkaline comet assay was used in this study to evaluate the genotoxic activity of sunlight (P exposure to sunlight in Group III showed genotoxic action in comparison to the other groups (P sunlight (UVA-B) in lymphocytes of mammals from 10:00 a.m. to 12:00 a.m., due to a higher intensity of UV in this tropical region.

  18. Vitamin D and Sunlight Exposure in Newly-Diagnosed Parkinson's Disease.

    Science.gov (United States)

    Wang, Juan; Yang, Deyu; Yu, Yu; Shao, Gaohai; Wang, Qunbo

    2016-03-04

    Circulating vitamin D has previously been found to be lower in patients with Parkinson's disease (PD), while the effects of sunlight exposure have not yet been fully investigated. Therefore, we evaluated the associations between serum vitamin D, vitamin D intake, sunlight exposure, and newly-diagnosed PD patients in a Chinese population. This case-control study measured serum 25-hydroxyvitamin D (25(OH)D) levels and sunlight exposure in 201 patients with newly-diagnosed PD and 199 controls without neurodegenerative diseases. Data on vitamin D intake and sunlight exposure were obtained using a self-report questionnaire. Multivariable logistic regressions were employed to evaluate the associations between serum 25(OH)D levels, sunlight exposure, and PD. Adjustments were made for sex, age, smoking, alcohol use, education, BMI, and vitamin D intake. There were significantly lower levels of serum 25(OH)D (20.6 ± 6.5 ng/mL), daily vitamin D intake (8.3 ± 3.7 g/day), and sunlight exposure (9.7 ± 4.1 h/week) in patients with PD compared to healthy controls (p sunlight exposure were 1 (reference), 0.809 (0.454, 1.443), 0.623 (0.345, 1.124) and 0.533 (0.294, 0.966), respectively. A significant positive correlation between serum 25(OH)D and sunlight exposure was found, but serum 25(OH)D was not correlated with daily vitamin D intake. This study indicates that lower levels of serum 25(OH)D and sunlight exposure are significantly associated with an increased risk for PD.

  19. Vitamin D and Sunlight Exposure in Newly-Diagnosed Parkinson’s Disease

    Science.gov (United States)

    Wang, Juan; Yang, Deyu; Yu, Yu; Shao, Gaohai; Wang, Qunbo

    2016-01-01

    Circulating vitamin D has previously been found to be lower in patients with Parkinson’s disease (PD), while the effects of sunlight exposure have not yet been fully investigated. Therefore, we evaluated the associations between serum vitamin D, vitamin D intake, sunlight exposure, and newly-diagnosed PD patients in a Chinese population. This case-control study measured serum 25-hydroxyvitamin D (25(OH)D) levels and sunlight exposure in 201 patients with newly-diagnosed PD and 199 controls without neurodegenerative diseases. Data on vitamin D intake and sunlight exposure were obtained using a self-report questionnaire. Multivariable logistic regressions were employed to evaluate the associations between serum 25(OH)D levels, sunlight exposure, and PD. Adjustments were made for sex, age, smoking, alcohol use, education, BMI, and vitamin D intake. There were significantly lower levels of serum 25(OH)D (20.6 ± 6.5 ng/mL), daily vitamin D intake (8.3 ± 3.7 g/day), and sunlight exposure (9.7 ± 4.1 h/week) in patients with PD compared to healthy controls (p sunlight exposure were 1 (reference), 0.809 (0.454, 1.443), 0.623 (0.345, 1.124) and 0.533 (0.294, 0.966), respectively. A significant positive correlation between serum 25(OH)D and sunlight exposure was found, but serum 25(OH)D was not correlated with daily vitamin D intake. This study indicates that lower levels of serum 25(OH)D and sunlight exposure are significantly associated with an increased risk for PD. PMID:26959053

  20. Screening individuals with intellectual disability, autism and Tourette's syndrome for KCNK9 mutations and aberrant DNA methylation within the 8q24 imprinted cluster

    DEFF Research Database (Denmark)

    Delgado, Marta Sánchez; Camprubí, Cristina; Tümer, Zeynep;

    2014-01-01

    The phenotype overlap between autism spectrum disorders (ASD) & intellectual disabilities (ID) is mirrored at the genetic level, with common genes being reported mutated in variety of developmental disabilities. However despite widespread genetic screening for mutations, in approximately 40....... Our findings suggest that mutations of KCNK9 or epigenetic disturbances within the PEG13 imprinted cluster do not significantly contribute to the cause of the developmental disabilities tested in this study. © 2014 Wiley Periodicals, Inc....

  1. TiO2-NiO p-n nanocomposite with enhanced sonophotocatalytic activity under diffused sunlight.

    Science.gov (United States)

    Vinoth, R; Karthik, P; Devan, K; Neppolian, B; Ashokkumar, Muthupandian

    2017-03-01

    TiO2-NiO composites with p-n junction were developed by assembling p-type NiO on n-type TiO2 using ultrasound assisted wet impregnation method. The sonophotocatalytic efficiencies of pure TiO2 and TiO2-NiO composites were evaluated under diffused sunlight using methyl orange (MO) as a model pollutant. The impregnation of NiO nanoparticles on TiO2 considerably enhanced the optical absorption in visible region (500-800nm) due to the formation of p-n junctions at the interface between TiO2 and NiO. The internal electric field induced by the p-n junction led to effective separation of electron-hole pairs and thereby generating a large amount of reactive species for the degradation of MO. The individual effect of ultrasound and diffused sunlight for the degradation of MO was found to be 30% and 6%, respectively. A synergy of 4.8 fold was achieved when ultrasound was combined with photocatalytic degradation process in the presence of diffused sunlight. The sonophotocatalytic activity of TiO2-NiO photocatalysts with different NiO loading was also evaluated and 10wt% NiO loading was found to be optimal. Moreover, 66% of Total Organic Carbon (TOC) removal was achieved with the optimized TiO2-NiO composite in 140min. In addition, the TiO2-NiO composite exhibited an enhanced photocurrent response under visible light illumination.

  2. On the origin of central abundances in the hot intra-cluster medium - I. Individual and average abundance ratios from XMM-Newton EPIC

    CERN Document Server

    Mernier, François; Pinto, Ciro; Kaastra, Jelle S; Kosec, Peter; Zhang, Yu-Ying; Mao, Junjie; Werner, Norbert

    2016-01-01

    The hot intra-cluster medium (ICM) is rich in metals, which are synthesized by supernovae (SNe) explosions and accumulate over time into the deep gravitational potential well of clusters of galaxies. Since most of the elements visible in X-rays are formed by type Ia (SNIa) and/or core-collapse (SNcc) supernovae, measuring their abundances gives us direct information on the nucleosynthesis products of billions of SNe since the epoch of the star formation peak (z ~ 2-3). In this study, we use the EPIC and RGS instruments onboard XMM-Newton to measure the abundances of 9 elements (O, Ne, Mg, Si, S, Ar, Ca, Fe and Ni) from a sample of 44 nearby cool-core galaxy clusters, groups, and elliptical galaxies. We find that the Fe abundance shows a large scatter (~20-40%) over the sample, within 0.2$r_{500}$ and, especially, 0.05$r_{500}$. Unlike the absolute Fe abundance, the abundance ratios (X/Fe) are quite uniform over the considered temperature range (~0.6-8 keV), and with a limited scatter. In addition to a unprece...

  3. [Progress in research of association between myopia and sunlight exposure in children].

    Science.gov (United States)

    Zhai, L L; Wu, X Y; Xu, S J; Tao, F B

    2016-11-10

    Myopia has become a major health problem on global scale due to its increasing high prevalence in the past few decades and gradual younger onset age. Accumulated epidemiological surveys have shown that decreased time of exposure to sunlight would be an inducement for the development of myopia. Increasing time spent outdoors and exposure to sunlight might be the most cost-effective and effective measure for children to prevent myopia. This paper summarizes the progress in research of the association between sunlight exposure and myopia in children and its mechanisms to provide new clues for the research on myopia prevention and control.

  4. Effect of sunlight on the survival of pathogenic E. coli in freshwater and sea water

    DEFF Research Database (Denmark)

    Surendraraj, Alagarsamy; Farvin, Sabeena; Thampuran, N.

    2011-01-01

    An enteropathogenic group of E. coli are the emerging category of pathogen of public health significance. Several recent pathogenic E. coli outbreaks are associated with drinking water. Aquaculture, the fast emerging food production sector also poses a pathogenic EHEC outbreak risk, as it regularly......) were studied for their survival under sunlight and darkness in fresh water and seawater. Effect of direct sunlight on the viable but nonculturable (VBNC) state of cultures was also studied. The results of the study indicated a distinct pattern between freshwater system and seawater system. Pathogenic E....... coli from different sources showed significantly higher level of destruction under direct sunlight than in complete darkness. A reduction of 1.1 to 5.7 log CFU was seen in fresh water after 90 to 105 min under direct sunlight and only 0.2 to 2 log reduction was observed in complete darkness in 5 to 96...

  5. Application of photoremovable protecting group for controlled release of plant growth regulators by sunlight.

    Science.gov (United States)

    Atta, Sanghamitra; Ikbal, Mohammed; Kumar, Ashutosh; Pradeep Singh, N D

    2012-06-01

    We report a novel technique for controlled release of plant growth regulators (PGRs) by sunlight using photoremovable protecting group (PRPG) as a delivery device. In the present work, carboxyl-containing PGRs of the auxin group [indoleacetic acid (IAA) and naphthoxyacetic acid (NOAA)] were chemically caged using PRPGs of coumarin derivatives. Photophysical studies showed that caged PGRs exhibited good fluorescence properties. Irradiation of caged PGRs by sunlight in both aqueous ethanol and soil media resulted in controlled release of PGRs. The results of the bioactivity experiments indicated that caged PGRs showed better enhancement in the root and shoot length growth of Cicer arietinum compared to PGRs after 10days of sunlight exposure. Our results indicated that use of PRPG as a delivery device for controlled release of PGRs by sunlight in soil holds great interest for field application since it can overcome the rapid loss of PGRs in environmental conditions.

  6. Sunlight affects aggregation and deposition of graphene oxide in the aquatic environment.

    Science.gov (United States)

    In this study, we investigate the role of simulated sunlight on the physicochemical properties, aggregation, and deposition of graphene oxide (GO) in aquatic environments. Results show that light exposure under varied environmental conditions significantly impacts the physicochem...

  7. Psychosocial aspects associated with use of sunscreen, natural sunlight exposure, and artificial tanning.

    Science.gov (United States)

    Ventenilla, Jessica; França, Katlein; Lotti, Torello; Keri, Jonette

    2017-02-08

    Natural and artificial tanning have become very popular in Western culture, yet at the same time, there is still a psychodermatology concern for this activity. Not much has been examined with the psychological aspects of tanning and sunscreen use. The purpose of this study is to examine the psychosocial effects associated with sun protection, natural, and artificial tanning among individuals 18 years old or older visiting the University of Miami Dermatology Outpatient Clinic. We distributed a survey on tanning and sunscreen use to 150 dermatology outpatients, hospital employees, and hospital visitors for three weeks during June/July 2015 asking about how often they tan, use sunscreen, and how they feel about this topic. Demographics, such as gender, ethnicity, and education were taken into consideration to examine the different responses in each category. Our results suggest that people's perception to tanning and sunscreen use have evolved over time. Most people in South Florida nowadays feel guilty when exposed to natural sunlight without sunscreen and do not tan frequently. The majority of the people, specifically women, utilize the recommended amount of sunscreen with a sun protection factor of 30-50. However, we can conclude that communication between social media and the general public can affect people's decision-making on tanning and sunscreen use with physician advice being the most effective method of encouraging people to use sunscreen. This study will add to the growing knowledge about psychodermatology.

  8. Toxicological impact of cadmium-based quantum dots towards aquatic biota: Effect of natural sunlight exposure

    Energy Technology Data Exchange (ETDEWEB)

    Silva, B.F. [Department of Biology, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Andreani, T. [Centro de Investigação em Química da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CITAB − Centre for Research and Technology of Agro-Environmental and Biological Sciences, University of Trás-os-Montes e Alto Douro, UTAD, Vila Real (Portugal); Gavina, A., E-mail: anacsgavina@gmail.com [Department of Biology, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Vieira, M.N. [Department of Biology, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); CIIMAR, Interdisciplinary Centre of Marine and Environmental Research, Rua dos Bragas, 289, 4050-123 Porto (Portugal); Pereira, C.M. [Centro de Investigação em Química da Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Department of Chemistry and Biochemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Rocha-Santos, T. [Department of Chemistry and Centre for Environmental and Marine Studies (CESAM), University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); and others

    2016-07-15

    Highlights: • Under sunlight exposure, all QDs form particle aggregates in the different media. • CdSeS/ZnS QDs showed lower toxic effects to V. fischeri before sunlight exposure. • Sunlight exposure decreased the toxicity of CdS 480 in all organisms. • Sunlight exposure increased the toxicity of CdS 380 QDs for D. magna. • Shell of QDs seemed to make them less harmful to aquatic organisms. - Abstract: Cadmium-based quantum dots (QDs) are increasingly applied in existent and emerging technologies, especially in biological applications due to their exceptional photophysical and functionalization properties. However, they are very toxic compounds due to the high reactive and toxic cadmium core. The present study aimed to determine the toxicity of three different QDs (CdS 380, CdS 480 and CdSeS/ZnS) before and after the exposure of suspensions to sunlight, in order to assess the effect of environmentally relevant irradiation levels in their toxicity, which will act after their release to the environment. Therefore, a battery of ecotoxicological tests was performed with organisms that cover different functional and trophic levels, such as Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris and Daphnia magna. The results showed that core-shell type QDs showed lower toxic effects to V. fischeri in comparison to core type QDs before sunlight exposure. However, after sunlight exposure, there was a decrease of CdS 380 and CdS 480 QD toxicity to bacterium. Also, after sunlight exposure, an effective decrease of CdSeS/ZnS and CdS 480 toxicity for D. magna and R. subcapitata, and an evident increase in CdS 380 QD toxicity, at least for D. magna, were observed. The results of this study suggest that sunlight exposure has an effect in the aggregation and precipitation reactions of larger QDs, causing the degradation of functional groups and formation of larger bulks which may be less prone to photo-oxidation due to their diminished surface area. The same

  9. Sunlight inactivation of faecal bacteria in waste stabilization ponds in a Sahelian region (Ouagadougou, Burkina Faso)

    Energy Technology Data Exchange (ETDEWEB)

    Maiga, Y.; Denyigba, K.; Wethe, J.; Ouattara, A. S.

    2009-07-01

    Waste stabilization ponds (WSPs) are an appropriate sewage treatment system for developing countries in Sahelian regions. Several studies on wastewater treatment in WSPs have shown that solar radiation is a major factor in the inactivation of faecal indicator, and that sunlight acts on interaction with other factors including dissolved oxygen (DO) and pH. However, the inactivation by sunlight is limited by the reduction of light penetration in ponds. (Author)

  10. Sunlight regulates the cutaneous production of vitamin D3 by causing its photodegradation

    Energy Technology Data Exchange (ETDEWEB)

    Webb, A.R.; DeCosta, B.R.; Holick, M.F.

    1989-05-01

    Exposure to sunlight initiates the formation of vitamin D3 in skin as the UV B radiation in the solar spectrum causes the photoconversion of 7-dehydrocholesterol to previtamin D3. A heat-induced isomerization then converts previtamin D3 to vitamin D3 over a period of days. A number of irradiation products of vitamin D3 are known to form upon irradiation with high intensity UV radiation, but the effect of subsequent exposures to sunlight on the vitamin D3 formed in skin is not known. To investigate this phenomenon, human skin containing vitamin D3 was exposed to sunlight in Boston. A model system of (/sup 3/H)vitamin D3 in methanol was also used to study the effects of sunlight on vitamin D3 throughout the year. Vitamin D3 proved to be exquisitely sensitive to sunlight, and once formed in the skin, exposure to sunlight resulted in its rapid photodegradation to a variety of photoproducts, including 5,6-transvitamin D3, suprasterol I, and suprasterol II.

  11. De Novo Assembly and Comparative Transcriptome Analyses of Red and Green Morphs of Sweet Basil Grown in Full Sunlight

    Science.gov (United States)

    Torre, Sara; Tattini, Massimiliano; Brunetti, Cecilia; Guidi, Lucia; Gori, Antonella; Marzano, Cristina; Landi, Marco; Sebastiani, Federico

    2016-01-01

    Sweet basil (Ocimum basilicum), one of the most popular cultivated herbs worldwide, displays a number of varieties differing in several characteristics, such as the color of the leaves. The development of a reference transcriptome for sweet basil, and the analysis of differentially expressed genes in acyanic and cyanic cultivars exposed to natural sunlight irradiance, has interest from horticultural and biological point of views. There is still great uncertainty about the significance of anthocyanins in photoprotection, and how green and red morphs may perform when exposed to photo-inhibitory light, a condition plants face on daily and seasonal basis. We sequenced the leaf transcriptome of the green-leaved Tigullio (TIG) and the purple-leaved Red Rubin (RR) exposed to full sunlight over a four-week experimental period. We assembled and annotated 111,007 transcripts. A total of 5,468 and 5,969 potential SSRs were identified in TIG and RR, respectively, out of which 66 were polymorphic in silico. Comparative analysis of the two transcriptomes showed 2,372 differentially expressed genes (DEGs) clustered in 222 enriched Gene ontology terms. Green and red basil mostly differed for transcripts abundance of genes involved in secondary metabolism. While the biosynthesis of waxes was up-regulated in red basil, the biosynthesis of flavonols and carotenoids was up-regulated in green basil. Data from our study provides a comprehensive transcriptome survey, gene sequence resources and microsatellites that can be used for further investigations in sweet basil. The analysis of DEGs and their functional classification also offers new insights on the functional role of anthocyanins in photoprotection. PMID:27483170

  12. De Novo Assembly and Comparative Transcriptome Analyses of Red and Green Morphs of Sweet Basil Grown in Full Sunlight.

    Science.gov (United States)

    Torre, Sara; Tattini, Massimiliano; Brunetti, Cecilia; Guidi, Lucia; Gori, Antonella; Marzano, Cristina; Landi, Marco; Sebastiani, Federico

    2016-01-01

    Sweet basil (Ocimum basilicum), one of the most popular cultivated herbs worldwide, displays a number of varieties differing in several characteristics, such as the color of the leaves. The development of a reference transcriptome for sweet basil, and the analysis of differentially expressed genes in acyanic and cyanic cultivars exposed to natural sunlight irradiance, has interest from horticultural and biological point of views. There is still great uncertainty about the significance of anthocyanins in photoprotection, and how green and red morphs may perform when exposed to photo-inhibitory light, a condition plants face on daily and seasonal basis. We sequenced the leaf transcriptome of the green-leaved Tigullio (TIG) and the purple-leaved Red Rubin (RR) exposed to full sunlight over a four-week experimental period. We assembled and annotated 111,007 transcripts. A total of 5,468 and 5,969 potential SSRs were identified in TIG and RR, respectively, out of which 66 were polymorphic in silico. Comparative analysis of the two transcriptomes showed 2,372 differentially expressed genes (DEGs) clustered in 222 enriched Gene ontology terms. Green and red basil mostly differed for transcripts abundance of genes involved in secondary metabolism. While the biosynthesis of waxes was up-regulated in red basil, the biosynthesis of flavonols and carotenoids was up-regulated in green basil. Data from our study provides a comprehensive transcriptome survey, gene sequence resources and microsatellites that can be used for further investigations in sweet basil. The analysis of DEGs and their functional classification also offers new insights on the functional role of anthocyanins in photoprotection.

  13. Cluster headache

    Science.gov (United States)

    Histamine headache; Headache - histamine; Migrainous neuralgia; Headache - cluster; Horton's headache; Vascular headache - cluster ... A cluster headache begins as a severe, sudden headache. The headache commonly strikes 2 to 3 hours after you fall ...

  14. Cluster Forests

    CERN Document Server

    Yan, Donghui; Jordan, Michael I

    2011-01-01

    Inspired by Random Forests (RF) in the context of classification, we propose a new clustering ensemble method---Cluster Forests (CF). Geometrically, CF randomly probes a high-dimensional data cloud to obtain "good local clusterings" and then aggregates via spectral clustering to obtain cluster assignments for the whole dataset. The search for good local clusterings is guided by a cluster quality measure $\\kappa$. CF progressively improves each local clustering in a fashion that resembles the tree growth in RF. Empirical studies on several real-world datasets under two different performance metrics show that CF compares favorably to its competitors. Theoretical analysis shows that the $\\kappa$ criterion is shown to grow each local clustering in a desirable way---it is "noise-resistant." A closed-form expression is obtained for the mis-clustering rate of spectral clustering under a perturbation model, which yields new insights into some aspects of spectral clustering.

  15. Frequency and origin of haplotypes associated with the beta-globin gene cluster in individuals with trait and sickle cell anemia in the Atlantic and Pacific coastal regions of Colombia.

    Science.gov (United States)

    Fong, Cristian; Lizarralde-Iragorri, María Alejandra; Rojas-Gallardo, Diana; Barreto, Guillermo

    2013-12-01

    Sickle cell anemia is a genetic disease with high prevalence in people of African descent. There are five typical haplotypes associated with this disease and the haplotypes associated with the beta-globin gene cluster have been used to establish the origin of African-descendant people in America. In this work, we determined the frequency and the origin of haplotypes associated with hemoglobin S in a sample of individuals with sickle cell anemia (HbSS) and sickle cell hemoglobin trait (HbAS) in coastal regions of Colombia. Blood samples from 71 HbAS and 79 HbSS individuals were obtained. Haplotypes were determined based on the presence of variable restriction sites within the β-globin gene cluster. On the Pacific coast of Colombia the most frequent haplotype was Benin, while on the Atlantic coast Bantu was marginally higher than Benin. Eight atypical haplotypes were observed on both coasts, being more diverse in the Atlantic than in the Pacific region. These results suggest a differential settlement of the coasts, dependent on where slaves were brought from, either from the Gulf of Guinea or from Angola, where the haplotype distributions are similar. Atypical haplotypes probably originated from point mutations that lost or gained a restriction site and/or by recombination events.

  16. Frequency and origin of haplotypes associated with the beta-globin gene cluster in individuals with trait and sickle cell anemia in the Atlantic and Pacific coastal regions of Colombia

    Directory of Open Access Journals (Sweden)

    Cristian Fong

    2013-01-01

    Full Text Available Sickle cell anemia is a genetic disease with high prevalence in people of African descent. There are five typical haplotypes associated with this disease and the haplotypes associated with the beta-globin gene cluster have been used to establish the origin of African-descendant people in America. In this work, we determined the frequency and the origin of haplotypes associated with hemoglobin S in a sample of individuals with sickle cell anemia (HbSS and sickle cell hemoglobin trait (HbAS in coastal regions of Colombia. Blood samples from 71 HbAS and 79 HbSS individuals were obtained. Haplotypes were determined based on the presence of variable restriction sites within the β-globin gene cluster. On the Pacific coast of Colombia the most frequent haplotype was Benin, while on the Atlantic coast Bantu was marginally higher than Benin. Eight atypical haplotypes were observed on both coasts, being more diverse in the Atlantic than in the Pacific region. These results suggest a differential settlement of the coasts, dependent on where slaves were brought from, either from the Gulf of Guinea or from Angola, where the haplotype distributions are similar. Atypical haplotypes probably originated from point mutations that lost or gained a restriction site and/or by recombination events.

  17. Star Clusters

    OpenAIRE

    Gieles, M.

    1993-01-01

    Star clusters are observed in almost every galaxy. In this thesis we address several fundamental problems concerning the formation, evolution and disruption of star clusters. From observations of (young) star clusters in the interacting galaxy M51, we found that clusters are formed in complexes of stars and star clusters. These complexes share similar properties with giant molecular clouds, from which they are formed. Many (70%) of the young clusters will not survive the fist 10 Myr, due to t...

  18. PRKCZ methylation is associated with sunlight exposure in a North American but not a Mediterranean population.

    Science.gov (United States)

    Aslibekyan, Stella; Dashti, Hassan S; Tanaka, Toshiko; Sha, Jin; Ferrucci, Luigi; Zhi, Degui; Bandinelli, Stefania; Borecki, Ingrid B; Absher, Devin M; Arnett, Donna K; Ordovas, Jose M

    2014-11-01

    Sunlight exposure has been shown to alter DNA methylation patterns across several human cell-types, including T-lymphocytes. Since epigenetic changes establish gene expression profiles, changes in DNA methylation induced by sunlight exposure warrant investigation. The purpose of this study was to assess the effects of sunlight exposure on CD4+ T-cell methylation patterns on an epigenome-wide scale in a North American population of European origin (n=991). In addition, we investigated the genetic contribution to epigenetic variation (methylQTL). We used linear regression to test the associations between methylation scores at 461,281 cytosine-phosphate-guanine (CpG) sites and sunlight exposure, followed by a genome-wide association analysis (methylQTL) to test for associations between methylation at the top CpG locus and common genetic variants, assuming an additive genetic model. We observed an epigenome-wide significant association between sunlight exposure and methylation status at cg26930596 (p=9.2×10(-8)), a CpG site located in protein kinase C zeta (PRKCZ), a gene previously shown to be entrained by light. MethylQTL analysis resulted in significant associations between cg26930596 and two intergenic single nucleotide polymorphisms on chromosome 3, rs4574216 (p=1.5×10(-10)) and rs4405858 (p=1.9×10(-9)). These common genetic variants reside downstream of WWTR1, a transcriptional co-activator of PRKCZ. Associations observed in the North American population, however, did not replicate in an independent Mediterranean cohort. Our preliminary results support the role of sunlight exposure in epigenetic processes, and lay the groundwork for future studies of the molecular link between sunlight and physiologic processes such as tumorigenesis and metabolism.

  19. Toxicological impact of cadmium-based quantum dots towards aquatic biota: Effect of natural sunlight exposure.

    Science.gov (United States)

    Silva, B F; Andreani, T; Gavina, A; Vieira, M N; Pereira, C M; Rocha-Santos, T; Pereira, R

    2016-07-01

    Cadmium-based quantum dots (QDs) are increasingly applied in existent and emerging technologies, especially in biological applications due to their exceptional photophysical and functionalization properties. However, they are very toxic compounds due to the high reactive and toxic cadmium core. The present study aimed to determine the toxicity of three different QDs (CdS 380, CdS 480 and CdSeS/ZnS) before and after the exposure of suspensions to sunlight, in order to assess the effect of environmentally relevant irradiation levels in their toxicity, which will act after their release to the environment. Therefore, a battery of ecotoxicological tests was performed with organisms that cover different functional and trophic levels, such as Vibrio fischeri, Raphidocelis subcapitata, Chlorella vulgaris and Daphnia magna. The results showed that core-shell type QDs showed lower toxic effects to V. fischeri in comparison to core type QDs before sunlight exposure. However, after sunlight exposure, there was a decrease of CdS 380 and CdS 480 QD toxicity to bacterium. Also, after sunlight exposure, an effective decrease of CdSeS/ZnS and CdS 480 toxicity for D. magna and R. subcapitata, and an evident increase in CdS 380 QD toxicity, at least for D. magna, were observed. The results of this study suggest that sunlight exposure has an effect in the aggregation and precipitation reactions of larger QDs, causing the degradation of functional groups and formation of larger bulks which may be less prone to photo-oxidation due to their diminished surface area. The same aggregation behaviour after sunlight exposure was observed for bare QDs. These results further emphasize that the shell of QDs seems to make them less harmful to aquatic biota, both under standard environmental conditions and after the exposure to a relevant abiotic factor like sunlight. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Wintering birds avoid warm sunshine: predation and the costs of foraging in sunlight.

    Science.gov (United States)

    Carr, Jennie M; Lima, Steven L

    2014-03-01

    Wintering birds can gain significant thermal benefits by foraging in direct sunlight. However, exposure to bright sunlight might make birds easier to detect by predators and may also cause visual glare that can reduce a bird's ability to monitor the environment. Thus, birds likely experience a trade-off between the thermal benefits and predation-related costs of foraging in direct sunlight. To examine this possible thermoregulation-predation trade-off, we monitored the behavior of mixed-species flocks of wintering emberizid sparrows foraging in alternating strips of sunlight and shade. On average, these sparrows routinely preferred to forage in the shade, despite midday air temperatures as much as 30 °C below their thermoneutral zone. This preference for shade was strongest at relatively high temperatures when the thermal benefits of foraging in sunlight were reduced, suggesting a thermoregulation-predation trade-off. Glare could be reduced if birds faced away from the sun while feeding in direct sunlight, but we found that foraging birds tended to face southward (the direction of the sun). We speculate that other factors, such as the likely direction of predator approach, may explain this southerly orientation, particularly if predators use solar glare to their advantage during an attack. This interpretation is supported by the fact that birds had the weakest southerly orientation on cloudy days. Wintering birds may generally avoid foraging in direct sunlight to minimize their risk of predation. However, given the thermal benefits of sunshine, such birds may benefit from foraging in habitats that provide a mosaic of sunlit and shaded microhabitats.

  1. Natural sunlight shapes crude oil-degradingbacterial communities in northern Gulf of Mexico surface waters

    Directory of Open Access Journals (Sweden)

    Hernando P Bacosa

    2015-12-01

    Full Text Available Following the Deepwater Horizon (DWH spill in 2010, an enormous amount of oil was observed in the deep and surface waters of the northern Gulf of Mexico. Surface waters are characterized by intense sunlight and high temperature during summer. While the oil-degrading bacterial communities in the deep-sea plume have been widely investigated, the effect of natural sunlight on those in oil polluted surface waters remains unexplored to date. In this study, we incubated surface water from the DWH site with amendments of crude oil, Corexit dispersant, or both for 36 d under natural sunlight in the northern Gulf of Mexico. The bacterial community was analyzed over time for total abundance, density of alkane and polycyclic aromatic hydrocarbon degraders, and community composition via pyrosequencing. Our results showed that, for treatments with oil and/or Corexit, sunlight significantly reduced bacterial diversity and evenness and was a key driver of shifts in bacterial community structure. In samples containing oil or dispersant, sunlight greatly reduced abundance of the Cyanobacterium Synechococcus but increased the relative abundances of Alteromonas, Marinobacter, Labrenzia, Sandarakinotalea, Bartonella, and Halomonas. Dark samples with oil were represented by members of Thalassobius, Winogradskyella, Alcanivorax, Formosa, Pseudomonas, Eubacterium, Erythrobacter, Natronocella, and Coxiella. Both oil and Corexit inhibited the Candidatus Pelagibacter with or without sunlight exposure. For the first time, we demonstrated the effects of light in structuring microbial communities in water with oil and/or Corexit. Overall, our findings improve understanding of oil pollution in surface water, and provide unequivocal evidence that sunlight is a key factor in determining bacterial community composition and dynamics in oil polluted marine waters.

  2. Varying relationship between 25-hydroxy-vitamin D, high density lipoprotein cholesterol, and serum 7-dehydrocholesterol reductase with sunlight exposure.

    Science.gov (United States)

    Patwardhan, Vivek G; Khadilkar, Anuradha V; Chiplonkar, Shashi A; Mughal, Zulf M; Khadilkar, Vaman V

    2015-01-01

    Cholesterol and cholecalciferol are synthesized from a common substrate 7-dehydrocholesterol. 7-dehydrocholesterol is converted to cholesterol by 7-dehydrocholesterol reductase enzyme (DHCR7) and to cholecalciferol by ultraviolet B radiation from sunlight. To examine the effect of sunlight exposure and serum DHCR7 levels on cholecalciferol and cholesterol levels and studying any interrelationship. In a cross-sectional observational study, 307 apparently healthy men (aged 40-60 years) were assessed for sunlight exposure, lipid levels, serum DHCR7, 25 hydroxyvitamin D (25(OH)D), body composition, and dietary milk calcium intake. Vitamin D deficiency (25(OH)D sunlight exposure (P sunlight exposure (sunlight exposure (1-2 h/d), there was no significant association. However, with higher sunlight exposure (>2 h/d), serum 25(OH)D concentrations were significantly negatively associated with HDL-C (P sunlight exposure, an inverse significant relationship was observed between 25(OH)D and serum DHCR7 (P sunlight exposure, no significant relationship was seen. 25(OH)D seems to show a varying relationship with HDL-C and serum DHCR7 at different durations of sunlight exposure. Copyright © 2015 National Lipid Association. Published by Elsevier Inc. All rights reserved.

  3. Cluster Correspondence Analysis.

    Science.gov (United States)

    van de Velden, M; D'Enza, A Iodice; Palumbo, F

    2017-03-01

    A method is proposed that combines dimension reduction and cluster analysis for categorical data by simultaneously assigning individuals to clusters and optimal scaling values to categories in such a way that a single between variance maximization objective is achieved. In a unified framework, a brief review of alternative methods is provided and we show that the proposed method is equivalent to GROUPALS applied to categorical data. Performance of the methods is appraised by means of a simulation study. The results of the joint dimension reduction and clustering methods are compared with the so-called tandem approach, a sequential analysis of dimension reduction followed by cluster analysis. The tandem approach is conjectured to perform worse when variables are added that are unrelated to the cluster structure. Our simulation study confirms this conjecture. Moreover, the results of the simulation study indicate that the proposed method also consistently outperforms alternative joint dimension reduction and clustering methods.

  4. THE RISKS OF SUNLIGHTING CLASSROOMS. An appraisal method to assess the severity of discomfort due to sunlight penetration in classrooms. Site of study: Primary school classrooms in Constantine (ALGERIA

    Directory of Open Access Journals (Sweden)

    D SAFFIDINE-ROUAG

    2001-12-01

    Full Text Available The westerly orientations for a large number of primary school classrooms in Constantine involved a serious environmental problem provoked by uncontrolled sunlight. Under such circumstances the schoolchildren had no choice than keep sitting under incident sunlight while performing their various school tasks.  Evidence of the severity of discomfort experienced by those pupils was investigated using observational methods. The results allowed to reach substantial conclusions about the risks of sunlighting classrooms.

  5. Hypovitaminosis D in patients undergoing kidney transplant: the importance of sunlight exposure.

    Science.gov (United States)

    Vilarta, Cristiane F; Unger, Marianna D; Dos Reis, Luciene M; Dominguez, Wagner V; David-Neto, Elias; Moysés, Rosa M; Titan, Silvia; Custodio, Melani R; Hernandez, Mariel J; Jorgetti, Vanda

    2017-07-01

    Recent studies have shown a high prevalence of hypovitaminosis D, defined as a serum 25-hydroxyvitamin D level less than 30 ng/ml, in both healthy populations and patients with chronic kidney disease. Patients undergoing kidney transplant are at an increased risk of skin cancer and are advised to avoid sunlight exposure. Therefore, these patients might share two major risk factors for hypovitaminosis D: chronic kidney disease and low sunlight exposure. This paper describes the prevalence and clinical characteristics of hypovitaminosis D among patients undergoing kidney transplant. We evaluated 25-hydroxyvitamin D serum levels in a representative sample of patients undergoing kidney transplant. We sought to determine the prevalence of hypovitaminosis D, compare these patients with a control group, and identify factors associated with hypovitaminosis D (e.g., sunlight exposure and dietary habits). Hypovitaminosis D was found in 79% of patients undergoing kidney transplant, and the major associated factor was low sunlight exposure. These patients had higher creatinine and intact parathyroid hormone serum levels, with 25-hydroxyvitamin D being inversely correlated with intact parathyroid hormone serum levels. Compared with the control group, patients undergoing kidney transplant presented a higher prevalence of 25-hydroxyvitamin D deficiency and lower serum calcium, phosphate and albumin but higher creatinine and intact parathyroid hormone levels. Our results confirmed the high prevalence of hypovitaminosis D in patients undergoing kidney transplant. Therapeutic strategies such as moderate sunlight exposure and vitamin D supplementation should be seriously considered for this population.

  6. Analysis of daylight performance of solar light pipes influenced by size and shape of sunlight captures

    Science.gov (United States)

    Wu, Yanpeng; Jin, Rendong; Zhang, Wenming; Liu, Li; Zou, Dachao

    2009-11-01

    Experimental investigations on three different sunlight captures with diameter 150mm, 212mm, 300mm were carried out under different conditions such as sunny conditions, cloudy conditions and overcast conditions and the two different size solar light pipes with diameter 360mm and 160mm under sunny conditions. The illuminance in the middle of the sunlight capture have relationship with its size, but not linear. To improve the efficiency of the solar light pipes, the structure and the performance of the sunlight capture must be enhanced. For example, University of Science and Technology Beijing Gymnasium, Beijing 2008 Olympic events of Judo and Taekwondo, 148 solar light pipes were installed with the diameter 530mm for each light pipe. Two sunlight captures with different shape were installed and tested. From the measuring results of the illuminance on the work plane of the gymnasium, the improvement sunlight captures have better effects with the size of augmenting and the machining of the internal surface at the same time, so that the refraction increased and the efficiency of solar light pipes improved. The better effects of supplementary lighting for the gymnasium have been achieved.

  7. Stainless steel in coastal seawater: sunlight counteracts biologically enhanced cathodic kinetics.

    Science.gov (United States)

    Eashwar, M; Lakshman Kumar, A; Sreedhar, G; Kennedy, J; Suresh Bapu, R H

    2014-09-01

    The influence of sunlight of varying intensity on the performance of UNS S30400 stainless steel (SS) was explored under conditions of natural biofilm development in coastal seawater. In a series of tests performed outdoors under an opaque roof, a range of shades were fashioned to impart varied amounts of diurnal light. These were an ambient level where the underwater illumination was ~ 5% of full sunlight, two intermediate ranges of lighting with ~ 2.5% and ~ 1% of the daylight, and a condition of full darkness. In comparison with the dark, increments of sunlight rendered the SS progressively less aggressive as cathodes in galvanic couples with UNS C70600 alloy. Likewise, welded SS with pre-initiated localized corrosion sites exhibited substantially lower rates of propagation with light. Thus, biofilms and sunlight affected cathodic kinetics in opposite ways. Surface analytical tests showed that the accumulation of manganese (Mn) within the biofilms was small relative to reports from waters of lower salinity. These results not only reveal that extremely low amounts of sunlight are adequate to offset the microbial effect, but also highlight the lack of convincing evidence for Mn cycling as a potent mechanism for enhanced cathodic kinetics in full-strength seawater.

  8. Clustering of resting state networks.

    Directory of Open Access Journals (Sweden)

    Megan H Lee

    Full Text Available BACKGROUND: The goal of the study was to demonstrate a hierarchical structure of resting state activity in the healthy brain using a data-driven clustering algorithm. METHODOLOGY/PRINCIPAL FINDINGS: The fuzzy-c-means clustering algorithm was applied to resting state fMRI data in cortical and subcortical gray matter from two groups acquired separately, one of 17 healthy individuals and the second of 21 healthy individuals. Different numbers of clusters and different starting conditions were used. A cluster dispersion measure determined the optimal numbers of clusters. An inner product metric provided a measure of similarity between different clusters. The two cluster result found the task-negative and task-positive systems. The cluster dispersion measure was minimized with seven and eleven clusters. Each of the clusters in the seven and eleven cluster result was associated with either the task-negative or task-positive system. Applying the algorithm to find seven clusters recovered previously described resting state networks, including the default mode network, frontoparietal control network, ventral and dorsal attention networks, somatomotor, visual, and language networks. The language and ventral attention networks had significant subcortical involvement. This parcellation was consistently found in a large majority of algorithm runs under different conditions and was robust to different methods of initialization. CONCLUSIONS/SIGNIFICANCE: The clustering of resting state activity using different optimal numbers of clusters identified resting state networks comparable to previously obtained results. This work reinforces the observation that resting state networks are hierarchically organized.

  9. Daytime Cognitive Performance in Response to Sunlight or Fluorescent Light Controlling for Sleep Duration

    Science.gov (United States)

    Ramos, Jhanic; Zamos, Adela; Rao, Rohit; Flynn-Evans, Erin

    2015-01-01

    Light is the primary synchronizer of the human circadian rhythm and also has acute alerting effects. Our study involves and comparing the alertness, performance and sleep of participants in the NASA Ames Sustainability Base, which uses sunlight as its primary light source, to in a traditional office building which uses overhead florescent lighting and varying exposure to natural light. The purpose of this study is to determine whether the use of natural lighting as a primary light source improves daytime cognitive function and promotes nighttime sleep. Participants from the Sustainability Base will be matched by gender and age to individuals working in other NASA buildings. In a prior study we found no differences in performance between those working in the Sustainability Base and those working in other buildings. Unexpectedly, we found that the average sleep duration among participants in both buildings was short, which likely obscured our ability to detect a difference the effect of light exposure on alertness. Given that such sleep deprivation has negative effects on cognitive performance, in this iteration of the study we are asking the participants to maintain a regular schedule with eight hours in bed each night in order to control for the effect of self-selected sleep restriction. Over the course of one week, we will ask the participants to wear actiwatches continuously, complete a psychomotor vigilance task (PVT) and digit symbol substitution task (DSST) three times per day, and keep daily sleepwork diaries. We hope that this study will provide data to support the idea that natural lighting and green architectural design are optimal to enhance healthy nighttime sleep patterns and daytime cognitive performance.

  10. Weighted Clustering

    DEFF Research Database (Denmark)

    Ackerman, Margareta; Ben-David, Shai; Branzei, Simina

    2012-01-01

    We investigate a natural generalization of the classical clustering problem, considering clustering tasks in which different instances may have different weights.We conduct the first extensive theoretical analysis on the influence of weighted data on standard clustering algorithms in both...... the partitional and hierarchical settings, characterizing the conditions under which algorithms react to weights. Extending a recent framework for clustering algorithm selection, we propose intuitive properties that would allow users to choose between clustering algorithms in the weighted setting and classify...

  11. Is casual exposure to summer sunlight effective at maintaining adequate vitamin D status?

    Science.gov (United States)

    Diffey, Brian L

    2010-08-01

    The advice that an adequate vitamin D status can be achieved by short, casual exposure to summer sunlight is ubiquitous. This review will examine the value of this advice. The results of experimental studies on changes in serum 25-hydroxyvitamin D [25(OH)D] concentrations following ultraviolet exposure are interpreted in the context of human exposure to sunlight. It is shown that current advice about modest sun exposure during the summer months does little in the way of boosting overall 25(OH)D levels, while sufficient sun exposure that could achieve a worthwhile benefit would compromise skin health. Failure to understand the nature of human exposure to sunlight has led to misguided advice concerning the sun exposure necessary for an adequate vitamin D status.

  12. Effect of sunlight on the survival of pathogenic E. coli in freshwater and sea water

    DEFF Research Database (Denmark)

    Surendraraj, Alagarsamy; Farvin, Sabeena; Thampuran, N.

    2011-01-01

    An enteropathogenic group of E. coli are the emerging category of pathogen of public health significance. Several recent pathogenic E. coli outbreaks are associated with drinking water. Aquaculture, the fast emerging food production sector also poses a pathogenic EHEC outbreak risk, as it regularly...... uses cow dung, a reservoir of this organism. Hence, a experiment was set up to study the duration of survival of pathogenic E. coli under sunlight and darkness. Eight pathogenic E. coli isolates from clinical (EPEC, ETEC, EHEC, EAEC), veterinary (CTE3, CTE4) and environmental sources (ASHE3, Rao II......) were studied for their survival under sunlight and darkness in fresh water and seawater. Effect of direct sunlight on the viable but nonculturable (VBNC) state of cultures was also studied. The results of the study indicated a distinct pattern between freshwater system and seawater system. Pathogenic E...

  13. Optical modeling of sunlight by using partially coherent sources in organic solar cells.

    Science.gov (United States)

    Alaibakhsh, Hamzeh; Darvish, Ghafar

    2016-03-01

    We investigate the effects of coherent and partially coherent sources in optical modeling of organic solar cells. Two different organic solar cells are investigated: one without substrate and the other with a millimeter-sized glass substrate. The coherent light absorption is calculated with rigorous coupled-wave analysis. The result of this method is convolved with a distribution function to calculate the partially coherent light absorption. We propose a new formulation to accurately model sunlight as a set of partially coherent sources. In the structure with glass substrate, the accurate sunlight modeling results in the elimination of coherent effects in the thick substrate, but the coherency in other layers is not affected. Using partially coherent sources instead of coherent sources for simulations with sunlight results in a smoother absorption spectrum, but the change in the absorption efficiency is negligible.

  14. De Novo Assembly and Comparative Transcriptome Analyses of Red and Green Morphs of Sweet Basil Grown in Full Sunlight

    National Research Council Canada - National Science Library

    Torre, Sara; Tattini, Massimiliano; Brunetti, Cecilia; Guidi, Lucia; Gori, Antonella; Marzano, Cristina; Landi, Marco; Sebastiani, Federico

    2016-01-01

    .... The development of a reference transcriptome for sweet basil, and the analysis of differentially expressed genes in acyanic and cyanic cultivars exposed to natural sunlight irradiance, has interest...

  15. Sunlight-stimulated phenylalanine ammonia-lyase (PAL activity and anthocyanin accumulation in exocarp of ‘Mahajanaka’ mango

    Directory of Open Access Journals (Sweden)

    Kobkiat Saengnil

    2011-11-01

    Full Text Available The activity of phenylalanine ammonia-lyase (PAL required for anthocyanin synthesis was stimulated by sunlight exposure resulting in the development of red colour in ‘Mahajanaka’ mango exocarp, which occurred only on the sunlight-exposed side of the fruit. The accumulation of anthocyanin was concurrent with the increase in PAL activity in the mature stage of the fruit. The exposed side of the fruit had higher PAL activity, endogenous sugar content, and anthocyanin accumulation than the unexposed side. It is concluded that sunlight increases red colour development of the mango exocarp by inducing PAL activity. Exposure to sunlight also enhances endogenous sugar accumulation in mango fruit.

  16. Railway suicide attempts are associated with amount of sunlight in recent days.

    Science.gov (United States)

    Kadotani, Hiroshi; Nagai, Yumiko; Sozu, Takashi

    2014-01-01

    To assess the relationship between hours of sunlight and railway suicide attempts, 3-7 days before these attempts. All railway suicide attempts causing railway suspensions or delays of 30 min or more between 2002 and 2006. We used a linear probability model to assess this relationship. This study was conducted at Tokyo, Kanagawa, and Osaka prefectures in Japan. Data were collected from the railway delay incident database of the Japanese Railway Technical Research Institute and public weather database of the Japan Meteorological Agency. About 971 railway suicides attempts occurred between 2002 and 2006 in Tokyo, Kanagawa, and Osaka. Less sunlight in the 7 days leading up to the railway suicide attempts was associated with a higher proportion of attempts (p=0.0243). Sunlight over the 3 days before an attempt had a similar trend (p=0.0888). No difference was found in sunlight hours between the days with (median: 5.6 [IQR: 1.1-8.8]) and without (median: 5.7 [IQR: 1.0-8.9]) railway suicide attempts in the evening. Finally, there was no apparent correlation between the railway suicide attempts and the monthly average sunlight hours of the attempted month or those of a month before. Railway suicides were not the main suicidal methods in Japan, We observed an increased proportion of railway suicide attempts after several days without sunlight. Light exposure (blue light or bright white light) in trains may be useful in reducing railway suicides, especially when consecutive days without sunshine are forecasted. © 2013 Elsevier B.V. All rights reserved.

  17. Individualizing Services, Individualizing Responsibility

    DEFF Research Database (Denmark)

    Garsten, Christina; Hollertz, Katarina; Jacobsson, Kerstin

    and responsibilising the unemployed individual? The paper finds that the individualisation that is taking place occurs as an individualisation of responsibility, more than as an individualisation of interventions. A related finding is that the social rights perspective is becoming performance......-oriented, and the normative demands placed on individuals appear increasingly totalizing, concerning the whole individual rather than the job-related aspects only. The paper is based on 23 in-depth interviews with individual clients as well as individual caseworkers and other professionals engaged in client-related work...

  18. Using metal nanostructures to form hydrocarbons from carbon dioxide, water and sunlight

    Science.gov (United States)

    Wang, Cong; Shen, Mengyan; Huo, Haibin; Ren, Haizhou; Johnson, Michael

    2011-12-01

    Based on experimental results, we propose a mechanism that allows the use of metal nanostructures to synthesize hydrocarbons and carbohydrates from carbon dioxide, water and sunlight. When sunlight impinges on cobalt nanostructures in a glass chamber, its intensity is greatly enhanced around the tips of the nanostructures through surface plasmon excitations focusing effect, and it then photodissociates the water and carbon dioxide molecules through enhanced photon absorptions of ions around the tips of the nanostructures. The photodissociated molecules in excited states remain on the cobalt nanostructure surfaces and various hydrocarbons and carbohydrates then will be formed around the surfaces at temperatures much lower than 100 oC.

  19. Test technology on CCD anti-sunlight jamming based on complex circumstance

    Science.gov (United States)

    Shi, Sheng-bing; Chen, Zhen-xing; Han, Fu-li

    2016-09-01

    Visible-light reconnaissance device based on CCD is applied to all kinds of weapons, CCD cannot work because of saturation when it faces intense light. Sun is intense light source in nature and assignably influences CCD performance. In this paper, aim is appraising CCD anti-sunlight ability, object reflection characteristic test system is designed, based on typical background reflection characteristic including grant, sand and so on, complex circumstance is formulated and test project is optimized with orthogonal design method, problem that is without test technology on CCD anti-sunlight jamming is solved.

  20. Cluster bomb ocular injuries

    Directory of Open Access Journals (Sweden)

    Ahmad M Mansour

    2012-01-01

    Full Text Available Purpose: To present the visual outcomes and ocular sequelae of victims of cluster bombs. Materials and Methods: This retrospective, multicenter case series of ocular injury due to cluster bombs was conducted for 3 years after the war in South Lebanon (July 2006. Data were gathered from the reports to the Information Management System for Mine Action. Results: There were 308 victims of clusters bombs; 36 individuals were killed, of which 2 received ocular lacerations and; 272 individuals were injured with 18 receiving ocular injury. These 18 surviving individuals were assessed by the authors. Ocular injury occurred in 6.5% (20/308 of cluster bomb victims. Trauma to multiple organs occurred in 12 of 18 cases (67% with ocular injury. Ocular findings included corneal or scleral lacerations (16 eyes, corneal foreign bodies (9 eyes, corneal decompensation (2 eyes, ruptured cataract (6 eyes, and intravitreal foreign bodies (10 eyes. The corneas of one patient had extreme attenuation of the endothelium. Conclusions: Ocular injury occurred in 6.5% of cluster bomb victims and 67% of the patients with ocular injury sustained trauma to multiple organs. Visual morbidity in civilians is an additional reason for a global ban on the use of cluster bombs.

  1. [The Impact of Sunlight Exposure on the Health of Older Adults].

    Science.gov (United States)

    Lin, Tzu-Chia; Liao, Yen-Chi

    2016-08-01

    Appropriate exposure to sunlight not only contributes to the production of vitamin D, which has been associated with enhanced bone health, mood, and cognitive functions, but also regulates the secretion of melatonin, which has been associated with the mediation of circadian rhythms, improved sleep quality, and optimized physical and social activity in the elderly. However, damage to the skin, eyes, and immune system has also been widely associated with long-term exposure to sunlight. Several studies have shown that many elderly, especially those that reside in institutions, do not receive sufficient sunlight exposure. Institutionalized elderly tend to participate in indoor activities and spend significant periods of time alone and asleep in front of the television. Furthermore, factors such as poor health, environmental design, indoor/outdoor preference, and activity design may impact the access of institutionalized elderly to sunlight more than their non-institutionalized peers. Therefore, we suggest that in addition to obtaining sufficient levels of vitamin D from their diet and from supplements, the elderly should perform outdoor activities for 20-30 minutes a day for five days each week. Furthermore, we suggest that the environment of the care facility should be made be more accessible and that some activities should be held outdoors.

  2. Preventive role of lens antioxidant defense mechanism against riboflavin-mediated sunlight damaging of lens crystallins.

    Science.gov (United States)

    Anbaraki, Afrooz; Khoshaman, Kazem; Ghasemi, Younes; Yousefi, Reza

    2016-10-01

    The main components of sunlight reaching the eye lens are UVA and visible light exerting their photo-damaging effects indirectly by the aid of endogenous photosensitizer molecules such as riboflavin (RF). In this study, lens proteins solutions were incubated with RF and exposed to the sunlight. Then, gel mobility shift analysis and different spectroscopic assessments were applied to examine the structural damaging effects of solar radiation on these proteins. Exposure of lens proteins to direct sunlight, in the presence of RF, leads to marked structural crosslinking, oligomerization and proteolytic instability. These structural damages were also accompanied with reduction in the emission fluorescence of Trp and Tyr and appearance of a new absorption peak between 300 and 400nm which can be related to formation of new chromophores. Also, photo-oxidation of lens crystallins increases their oligomeric size distribution as examined by dynamic light scattering analysis. The above mentioned structural insults, as potential sources of sunlight-induced senile cataract and blindness, were significantly attenuated in the presence of ascorbic acid and glutathione which are two important components of lens antioxidant defense system. Therefore, the powerful antioxidant defense mechanism of eye lens is an important barrier against molecular photo-damaging effects of solar radiations during the life span. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Reversible degradation in ITO-containing organic photovoltaics under concentrated sunlight

    NARCIS (Netherlands)

    Galagan, Y.O.; Mescheloff, A.; Veenstra, S.C.; Andriessen, H.A.J.M.; Katz, E.A.

    2015-01-01

    Stabilities of ITO-containing and ITO-free organic solar cells were investigated under simulated AM 1.5G illumination and under concentrated natural sunlight. In both cases ITO-free devices exhibit high stability, while devices containing ITO show degradation of their photovoltaic performance. The a

  4. The relationships among birth season, sunlight exposure during infancy, and allergic disease.

    Science.gov (United States)

    Hwang, Jung Min; Oh, Se Hyun; Shin, Mee Yong

    2016-05-01

    The recent increase in the prevalence of allergic diseases is hypothetically attributed to immune dysregulation in turn caused by a reduction in exposure to sunlight. We explored relationships between birth season, sunlight exposure, exercise duration, and an allergic disease. We performed a questionnaire-based survey on allergic diseases among elementary school students. Birth time was categorized according to the season (summer and winter). The prevalence of atopic dermatitis (AD) "symptoms ever" was higher in the children born in winter than in those born in summer (adjusted odds ratio [aOR], 1.24; 95% confidence interval [CI], 1.03-1.49; P=0.024). Birth in winter was associated with an increase in the "symptoms in the past 12 months" prevalence of food allergy (FA) (aOR, 1.56; 95% CI, 1.09-2.24; P=0.015). The lifetime prevalence of allergic diseases except FA was higher in the children whose parents considered their sunlight exposure prior to 24 months of ageas inadequate than those who considered their exposure as adequate ("diagnosis ever" asthma: aOR, 1.4; 95% CI, 1.17-1.67; Psunlight exposure nor exercise duration was associated with the prevalence of an allergic disease. Birth in winter may be associated with development of AD and FA. Inadequate sunlight exposure before the age of 24 months might possibly increase the risks of development of asthma, AR, and AD.

  5. Hybrid sunlight/LED illumination and renewable solar energy saving concepts for indoor lighting.

    Science.gov (United States)

    Tsuei, Chih-Hsuan; Sun, Wen-Shing; Kuo, Chien-Cheng

    2010-11-08

    A hybrid method for using sunlight and light-emitting diode (LED) illumination powered by renewable solar energy for indoor lighting is simulated and presented in this study. We can illuminate an indoor space and collect the solar energy using an optical switching system. When the system is turned off, the full spectrum of the sunlight is concentrated by a concentrator, to be absorbed by solar photovoltaic devices that provide the electricity to power the LEDs. When the system is turned on, the sunlight collected by the concentrator is split into visible and non-visible rays by a beam splitter. The visible rays pass through the light guide into a light box where it is mixed with LED light to ultimately provide uniform illumination by a diffuser. The non-visible rays are absorbed by the solar photovoltaic devices to provide electrical power for the LEDs. Simulation results show that the efficiency of the hybrid sunlight/LED illumination with the renewable solar energy saving design is better than that of LED and traditional lighting systems.

  6. Greenhouse Effect: Temperature of a Metal Sphere Surrounded by a Glass Shell and Heated by Sunlight

    Science.gov (United States)

    Nguyen, Phuc H.; Matzner, Richard A.

    2012-01-01

    We study the greenhouse effect on a model satellite consisting of a tungsten sphere surrounded by a thin spherical, concentric glass shell, with a small gap between the sphere and the shell. The system sits in vacuum and is heated by sunlight incident along the "z"-axis. This development is a generalization of the simple treatment of the…

  7. Degradation of benzotriazole and benzothiazole in treatment wetlands and by artificial sunlight.

    Science.gov (United States)

    Felis, Ewa; Sochacki, Adam; Magiera, Sylwia

    2016-11-01

    Laboratory-scale experiments were performed using unsaturated subsurface-flow treatment wetlands and artificial sunlight (with and without TiO2) to study the efficiency of benzotriazole and benzothiazole removal and possible integration of these treatment methods. Transformation products in the effluent from the treatment wetlands and the artificial sunlight reactor were identified by high performance liquid chromatography coupled with tandem mass spectrometry. The removal of benzothiazole in the vegetated treatment wetlands was 99.7%, whereas the removal of benzotriazole was 82.8%. The vegetation positively affected only the removal of benzothiazole. The major transformation products in the effluents from the treatment wetlands were methylated and hydroxylated derivatives of benzotriazole, and hydroxylated derivatives of benzothiazole. Hydroxylation was found to be the main process governing the transformation pathway for both compounds in the artificial sunlight experiment (with and without TiO2). Benzotriazole was not found to be susceptible to photodegradation in the absence of TiO2. The integration of the sunlight-induced processes (with TiO2) with subsurface-flow treatment wetlands caused further elimination of the compounds (42% for benzotriazole and 58% for benzothiazole). This was especially significant for the elimination of benzotriazole, because the removal of this compound was 96% in the coupled processes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Inactivation of enteropathogenic E. coli by solar disinfection (SODIS) under simulated sunlight conditions

    Energy Technology Data Exchange (ETDEWEB)

    Ubomba-Jaswa, E; Boyle, M A R; McGuigan, K G [Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2 (Ireland)], E-mail: kmcguigan@rcsi.ie

    2008-02-01

    Solar Disinfection (SODIS) is a low cost water treatment method currently used in communities that do not have year round access to safe water. However, there is still reluctance in widespread adoption of this treatment method due to a number of limitations. An important limitation is the lack of SODIS inactivation studies on some waterborne pathogens in the developing world. SODIS inactivation of enteropathogenic E. coli (EPEC), a major cause of infantile diarrhoea is reported for the first time under simulated sunlight conditions and following a natural temperature profile. EPEC was exposed to simulated sunlight (885Wm{sup -2}) for periods up to a cumulative time of 4 hours. Inactivation was determined by a log reduction in growth of the organisms. The temperature (deg. C) of the water was taken at every time point. After 4 hours exposure EPEC was completely inactivated (7 log reduction) by SODIS. Imposing a realistic water temperature profile (min-max) concomitant with irradiation produces a greater kill of EPEC. Maintaining simulated sunlight experiments at a high fixed temperature may result in over-estimation of inactivation. Following a natural water temperature profile will result in more reliable inactivation comparable with those that might be obtained under natural sunlight conditions.

  9. Inactivation of enteropathogenic E. coli by solar disinfection (SODIS) under simulated sunlight conditions

    Science.gov (United States)

    Ubomba-Jaswa, E.; Boyle, M. A. R.; McGuigan, K. G.

    2008-02-01

    Solar Disinfection (SODIS) is a low cost water treatment method currently used in communities that do not have year round access to safe water. However, there is still reluctance in widespread adoption of this treatment method due to a number of limitations. An important limitation is the lack of SODIS inactivation studies on some waterborne pathogens in the developing world. SODIS inactivation of enteropathogenic E. coli (EPEC), a major cause of infantile diarrhoea is reported for the first time under simulated sunlight conditions and following a natural temperature profile. EPEC was exposed to simulated sunlight (885Wm-2) for periods up to a cumulative time of 4 hours. Inactivation was determined by a log reduction in growth of the organisms. The temperature (°C) of the water was taken at every time point. After 4 hours exposure EPEC was completely inactivated (7 log reduction) by SODIS. Imposing a realistic water temperature profile (min-max) concomitant with irradiation produces a greater kill of EPEC. Maintaining simulated sunlight experiments at a high fixed temperature may result in over --estimation of inactivation. Following a natural water temperature profile will result in more reliable inactivation comparable with those that might be obtained under natural sunlight conditions.

  10. 40 CFR 795.70 - Indirect photolysis screening test: Sunlight photolysis in waters containing dissolved humic...

    Science.gov (United States)

    2010-07-01

    ... mobile phase is 2 percent acetic acid, 50 percent acetonitrile and 48 percent water (2 mL/min flow rate... of sunlight actinometers.” Environmental Science and Technology, 6:815. (1982). (6) Haag H.R., Hoigne... Science and Technology, 11:359. (1977). (20) Zepp, R.G., Wolfe N.L., Baughman G.L., Hollis R.C....

  11. Effectiveness of sensor monitoring in an occupational therapy rehabilitation program for older individuals after hip fracture, the SO-HIP trial: study protocol of a three-arm stepped wedge cluster randomized trial.

    Science.gov (United States)

    Pol, Margriet C; Ter Riet, Gerben; van Hartingsveldt, Margo; Kröse, Ben; de Rooij, Sophia E; Buurman, Bianca M

    2017-01-03

    The performance of activities of daily living (ADL) at home is important for the recovery of older individuals after hip fracture. However, 20-90% of these individuals lose ADL function and never fully recover. It is currently unknown to what extent occupational therapy (OT) with coaching based on cognitive behavioral treatment (CBT) improves recovery. The same holds for sensor monitoring-based coaching in addition to OT. Here, we describe the design of a study investigating the effect of sensor monitoring embedded in an OT rehabilitation program on the recovery of ADL among older individuals after hip fracture. Six nursing homes will be randomized in a three-arm stepped wedge cluster randomized trial. All nursing homes will initially provide standard care. At designated time points, nursing homes, successively and in random order, will cross over to the provision of OT and at the next time point, to sensor monitoring-enhanced OT. A total of 288 older individuals, previously living alone in the community, who after a hip fracture were admitted to a geriatric rehabilitation ward for a short-term rehabilitation, will be enrolled. Individuals in the first intervention group (OTc) will participate in an OT rehabilitation program with coaching based on cognitive behavioral therapy (CBT) principles. In the sensor monitoring group, sensor monitoring is added to the OT intervention (OTcsm). Participants will receive a sensor monitoring system consisting of (i) an activity monitor during nursing home stay, (ii) a sensor monitoring system at home and a (iii) a web-based feedback application. These components will be embedded in the OT. The OT consists of a weekly session with an occupational therapist during the nursing home stay followed by four home visits and four telephone consultations. The primary outcome is patient-perceived daily functioning at 6 months, assessed using the Canadian Occupational Performance Measure (COPM). As far as we know, this study is the first

  12. Meaningful Clusters

    Energy Technology Data Exchange (ETDEWEB)

    Sanfilippo, Antonio P.; Calapristi, Augustin J.; Crow, Vernon L.; Hetzler, Elizabeth G.; Turner, Alan E.

    2004-05-26

    We present an approach to the disambiguation of cluster labels that capitalizes on the notion of semantic similarity to assign WordNet senses to cluster labels. The approach provides interesting insights on how document clustering can provide the basis for developing a novel approach to word sense disambiguation.

  13. Sunlight exposure increases vitamin D sufficiency in growing pigs fed a diet formulated to exceed requirements.

    Science.gov (United States)

    Alexander, B M; Ingold, B C; Young, J L; Fensterseifer, S R; Wechsler, P J; Austin, K J; Larson-Meyer, D E

    2017-04-01

    Traditional confinement practices limit exposure to sunlight and vitamin D synthesis, and vitamin insufficiency occurs even with dietary supplementation. The aim of this study was to determine the effect of limited sun exposure on serum concentration of vitamin D and the expression of vitamin D synthesizing enzymes in the liver and kidney of pigs on a vitamin D sufficient diet. White-pigmented grower pigs (29.7 ± 2.3 kg) fed 15% CP diet ad libitum providing >1,200 IU vitamin D3/kg of feed were exposed to sunlight for 1 h each day at solar noon for 14 d at the spring equinox (March pigs, n = 10) or summer solstice (June pigs, n = 5) and again before slaughter in June (March pigs) and September (June pigs). Blood for the analysis of 25(OH)D was collected before and after sunlight exposure. Traditionally housed pigs served as controls. After initial sun exposure, blood samples were collected from June pigs daily for 5 d and weekly for 8 wk to determine vitamin D3 and 25(OH)D decay, respectively. Kidney and liver samples were collected from the June pigs at slaughter after sun exposure for analysis of messenger RNA expression of vitamin D binding protein and synthesizing/degrading enzymes. Average daily gain (ADG) was not influenced (P > 0.5) by sunlight exposure. June pigs had fewer days on feed, lower (P = 0.003) ADG and were slaughtered at a lighter (P Exposure to sunlight increased (P sunlight exposure increased serum concentration of 25(OH)D in March pigs by 200% and June pigs by 67%. Serum concentration of vitamin D3 was decreased (P exposure. Expression of vitamin D binding protein, vitamin D synthesizing CYP2R1, CYP27A1, CYP2D25, or degrading enzyme CYP24A1 were not influenced (P ≥ 0.19) by sunlight exposure. Expression of CYP27B1 was decreased (P = 0.04) in the kidney but tended to be increased (P = 0.06) in the liver after sun exposure. These results suggest limited sun exposure can efficiently increase serum concentration of vitamin D in growing pigs

  14. IS THERE A LINK BETWEEN SUNLIGHT EXPOSURE AND 25-HYDROXYVITAMIN D DEFICIENCY IN CHRONIC KIDNEY DISEASE PATIENTS?

    Directory of Open Access Journals (Sweden)

    Angela Yee-Moon Wang

    2012-06-01

    In conclusion, our study confirmed an extremely high prevalence of vitamin D deficiency and an important association between outdoor sunlight exposure and 25(OHD deficiency in Chinese stage 3-5 CKD patients. Further study is needed to determine whether increasing daily outdoor sunlight exposure may represent a cost-free treatment for correcting nutritional 25(OHD deficiency in the CKD population.

  15. Coma cluster of galaxies

    Science.gov (United States)

    1999-01-01

    Atlas Image mosaic, covering 34' x 34' on the sky, of the Coma cluster, aka Abell 1656. This is a particularly rich cluster of individual galaxies (over 1000 members), most prominently the two giant ellipticals, NGC 4874 (right) and NGC 4889 (left). The remaining members are mostly smaller ellipticals, but spiral galaxies are also evident in the 2MASS image. The cluster is seen toward the constellation Coma Berenices, but is actually at a distance of about 100 Mpc (330 million light years, or a redshift of 0.023) from us. At this distance, the cluster is in what is known as the 'Hubble flow,' or the overall expansion of the Universe. As such, astronomers can measure the Hubble Constant, or the universal expansion rate, based on the distance to this cluster. Large, rich clusters, such as Coma, allow astronomers to measure the 'missing mass,' i.e., the matter in the cluster that we cannot see, since it gravitationally influences the motions of the member galaxies within the cluster. The near-infrared maps the overall luminous mass content of the member galaxies, since the light at these wavelengths is dominated by the more numerous older stellar populations. Galaxies, as seen by 2MASS, look fairly smooth and homogeneous, as can be seen from the Hubble 'tuning fork' diagram of near-infrared galaxy morphology. Image mosaic by S. Van Dyk (IPAC).

  16. Photosensitized rose Bengal-induced phototoxicity on human melanoma cell line under natural sunlight exposure.

    Science.gov (United States)

    Srivastav, Ajeet K; Mujtaba, Syed Faiz; Dwivedi, Ashish; Amar, Saroj K; Goyal, Shruti; Verma, Ankit; Kushwaha, Hari N; Chaturvedi, Rajnish K; Ray, Ratan Singh

    2016-03-01

    Rose Bengal (RB) is an anionic water-soluble xanthene dye, which used for many years to assess eye cornea and conjunctiva damage. RB showed strong absorption maxima (λmax) under visible light followed by UV-B and UV-A. RB under sunlight exposure showed a time-dependent photodegradation. Our results show that photosensitized RB generates (1)O2 via Type-II photodynamic pathway and induced DNA damage under sunlight/UV-R exposure. 2'dGuO degradation, micronuclei formation, and single- and double-strand breakage were the outcome of photogenotoxicity caused by RB. Quenching studies with NaN3 advocate the involvement of (1)O2 in RB photogenotoxicity. RB induced linoleic acid photoperoxidation, which was parallel to (1)O2-mediated DNA damage. Oxidative stress in A375 cell line (human melanoma cell line) was detected through DCF-DA assay. Photosensitized RB decreased maximum cellular viability under sunlight followed by UV-B and UV-A exposures. Apoptosis was detected as a pattern of cell death through the increased of caspase-3 activity, decreased mitochondrial membrane potential, and PS translocation through inner to outer plasma membrane. Increased cytosolic levels of Bax also advocate the apoptotic cell death. We propose a p53-mediated apoptosis via increased expression of Bax gene and protein. Thus, the exact mechanism behind RB phototoxicity was the involvement of (1)O2, which induced oxidative stress-mediated DNA and membrane damage, finally apoptotic cell death under natural sunlight exposure. The study suggests that after the use of RB, sunlight exposure may avoid to prevent from its harmful effects. Copyright © 2015. Published by Elsevier B.V.

  17. Effect of Sunlight Radiation on the Growth and Chemical Constituents of Salvia plebeia R.Br.

    Directory of Open Access Journals (Sweden)

    Hyun-Jae Jang

    2017-08-01

    Full Text Available This study investigated the chemical composition changes of Salvia plebeia R.Br. cultivated under different light sources, including florescent light and sunlight. The plants were exposed to fluorescent light for four months and sunlight and then examined for the next 5–7 months. Plants were harvested monthly during the seven months, and we examined whether the difference in light source affected the phenolic and flavonoid contents and antioxidant activity. A simple and reliable HPLC method using a PAH C18 column was applied for the quantitative analysis of two triterpenoids from the S. plebeia groups. Oleanolic acid (OA and ursolic acid (UA showed good linearity (R2 > 0.9999 within the test ranges (0.005–0.05 mg/mL, and the average percentage recoveries of the OA and UA were 95.1–104.8% and 97.2–107.1%, respectively. The intra- and inter-day relative standard deviations (RSDs were less than 2.0%. After exposure to sunlight, the phenolic contents, including rosmarinic acid, showed a reduced tendency, whereas the flavonoid contents, including homoplantaginin and luteolin 7-glucoside, were increased. The content of the triterpenoids also showed an increased tendency under sunlight irradiation, but the variance was not larger than those of the phenolic and flavonoid contents. Among experimental groups, the group harvested at six months, having been exposed to sunlight for two months, showed the most potent antioxidant activity. Therefore, these results showed that the chemical composition and antioxidant activities of S. plebeia R.Br. was affected from environmental culture conditions, such as light source. Our studies will be useful for the development of functional materials using S. plebeia R.Br.

  18. Effect of Sunlight Radiation on the Growth and Chemical Constituents of Salvia plebeia R.Br.

    Science.gov (United States)

    Jang, Hyun-Jae; Lee, Seung-Jae; Kim, Cha Young; Hwang, Joo Tae; Choi, Jung Ho; Park, Jee Hun; Lee, Seung Woong; Rho, Mun-Chual

    2017-08-01

    This study investigated the chemical composition changes of Salvia plebeia R.Br. cultivated under different light sources, including florescent light and sunlight. The plants were exposed to fluorescent light for four months and sunlight and then examined for the next 5-7 months. Plants were harvested monthly during the seven months, and we examined whether the difference in light source affected the phenolic and flavonoid contents and antioxidant activity. A simple and reliable HPLC method using a PAH C18 column was applied for the quantitative analysis of two triterpenoids from the S. plebeia groups. Oleanolic acid (OA) and ursolic acid (UA) showed good linearity (R² > 0.9999) within the test ranges (0.005-0.05 mg/mL), and the average percentage recoveries of the OA and UA were 95.1-104.8% and 97.2-107.1%, respectively. The intra- and inter-day relative standard deviations (RSDs) were less than 2.0%. After exposure to sunlight, the phenolic contents, including rosmarinic acid, showed a reduced tendency, whereas the flavonoid contents, including homoplantaginin and luteolin 7-glucoside, were increased. The content of the triterpenoids also showed an increased tendency under sunlight irradiation, but the variance was not larger than those of the phenolic and flavonoid contents. Among experimental groups, the group harvested at six months, having been exposed to sunlight for two months, showed the most potent antioxidant activity. Therefore, these results showed that the chemical composition and antioxidant activities of S. plebeia R.Br. was affected from environmental culture conditions, such as light source. Our studies will be useful for the development of functional materials using S. plebeia R.Br.

  19. Fuzzy clustering evaluation of the discrimination power of UV-Vis and (±) ESI-MS detection system in individual or coupled RPLC for characterization of Ginkgo Biloba standardized extracts.

    Science.gov (United States)

    Medvedovici, Andrei; Albu, Florin; Naşcu-Briciu, Rodica Domnica; Sârbu, Costel

    2014-02-01

    Discrimination power evaluation of UV-Vis and (±) electrospray ionization/mass spectrometric techniques, (ESI-MS) individually considered or coupled as detectors to reversed phase liquid chromatography (RPLC) in the characterization of Ginkgo Biloba standardized extracts, is used in herbal medicines and/or dietary supplements with the help of Fuzzy hierarchical clustering (FHC). Seventeen batches of Ginkgo Biloba commercially available standardized extracts from seven manufacturers were measured during experiments. All extracts were within the criteria of the official monograph dedicated to dried refined and quantified Ginkgo extracts, in the European Pharmacopoeia. UV-Vis and (±) ESI-MS spectra of the bulk standardized extracts in methanol were acquired. Additionally, an RPLC separation based on a simple gradient elution profile was applied to the standardized extracts. Detection was made through monitoring UV absorption at 220 nm wavelength or the total ion current (TIC) produced through (±) ESI-MS analysis. FHC was applied to raw, centered and scaled data sets, for evaluating the discrimination power of the method with respect to the origins of the extracts and to the batch to batch variability. The discrimination power increases with the increase of the intrinsic selectivity of the spectral technique being used: UV-Viscluster analysis (CA) and principal components analysis (PCA) indicates that the FHC algorithm produces better classification. However, PCA and CA may be successfully applied to discriminate between the manufacturing sources of the standardized extracts, and at some extent, to monitor the inter-batch variability. Although the chromatographic dimension sensibly contributes to the discrimination power, spectral MS data may be used as the lone powerful holistic alternative in characterization of standardized Ginkgo Biloba extracts. © 2013 Elsevier B

  20. Effect of sunlight exposure on cognitive function among depressed and non-depressed participants: a REGARDS cross-sectional study.

    Science.gov (United States)

    Kent, Shia T; McClure, Leslie A; Crosson, William L; Arnett, Donna K; Wadley, Virginia G; Sathiakumar, Nalini

    2009-07-28

    Possible physiological causes for the effect of sunlight on mood are through the suprachiasmatic nuclei and evidenced by serotonin and melatonin regulation and its associations with depression. Cognitive function involved in these same pathways may potentially be affected by sunlight exposure. We evaluated whether the amount of sunlight exposure (i.e. insolation) affects cognitive function and examined the effect of season on this relationship. We obtained insolation data for residential regions of 16,800 participants from a national cohort study of blacks and whites, aged 45+. Cognitive impairment was assessed using a validated six-item screener questionnaire and depression status was assessed using the Center for Epidemiologic Studies Depression Scale. Logistic regression was used to find whether same-day or two-week average sunlight exposure was related to cognitive function and whether this relationship differed by depression status. Among depressed participants, a dose-response relationship was found between sunlight exposure and cognitive function, with lower levels of sunlight associated with impaired cognitive status (odds ratio = 2.58; 95% CI 1.43-6.69). While both season and sunlight were correlated with cognitive function, a significant relation remained between each of them and cognitive impairment after controlling for their joint effects. The study found an association between decreased exposure to sunlight and increased probability of cognitive impairment using a novel data source. We are the first to examine the effects of two-week exposure to sunlight on cognition, as well as the first to look at sunlight's effects on cognition in a large cohort study.

  1. Sunlight exposure during leisure activities and risk of prostate cancer in Montréal, Canada, 2005-2009.

    Science.gov (United States)

    Yu, Jennifer; Lavoué, Jérôme; Parent, Marie-Élise

    2014-07-28

    Prostate cancer (PCa) is the leading cause of cancer in men in many developed countries, but no modifiable risk factors have been identified. A handful of analytical studies have suggested a possible etiological role for sunlight exposure. We report here on the association between leisure-time sunlight exposure during adulthood and PCa risk in the context of a population-based case-control study. In all, 1,904 PCa cases were ascertained across Montreal French hospitals between 2005 and 2009. Concurrently, 1,962 population controls, frequency matched to cases by age (±5 years), were selected from the electoral list for French-speakers in Greater Montreal. Interviews elicited the frequency of engagement in any leisure activity during adulthood. This was used to derive cumulative sunlight exposure indices: a cumulative number of leisure activities events entailing sunlight exposure and a cumulative duration of sunlight exposure during leisure activities. Unconditional logistic regression was conducted to yield odds ratios (OR) and 95% confidence intervals (CI) for estimating the association between sunlight exposure indices and PCa risk, adjusting for age, ancestry, family history of PCa, PCa screening, education, solar protection, body mass index and physical activity. Compared with men in the upper quartile category for the number of sunlight exposure events, men never exposed during leisure time had an OR of 1.32 (95% CI: 0.82-2.14). ORs were 1.11, 0.91 and 1.00 for the first to the third quartiles of exposure, respectively. Similar results were observed for cumulative duration of exposure to sunlight, and by PCa aggressiveness. These findings provide little evidence of an association between sunlight exposure during leisure-time and PCa risk. Men with no sunlight exposure appeared at somewhat higher risks but none of the estimates achieved statistical significance.

  2. Cluster Lenses

    CERN Document Server

    Kneib, Jean-Paul; 10.1007/s00159-011-0047-3

    2012-01-01

    Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining...

  3. Staphylococcus aureus Strain Newman Photoinactivation and Cellular Response to Sunlight Exposure.

    Science.gov (United States)

    McClary, Jill S; Sassoubre, Lauren M; Boehm, Alexandria B

    2017-09-01

    Sunlight influences microbial water quality of surface waters. Previous studies have investigated photoinactivation mechanisms and cellular photostress responses of fecal indicator bacteria (FIB), including Escherichia coli and enterococci, but further work is needed to characterize photostress responses of bacterial pathogens. Here we investigate the photoinactivation of Staphylococcus aureus (strain Newman), a pigmented, waterborne pathogen of emerging concern. We measured photodecay using standard culture-based assays and cellular membrane integrity and investigated photostress response by measuring the relative number of mRNA transcripts of select oxidative stress, DNA repair, and metabolism genes. Photoinactivation experiments were performed in both oxic and anoxic systems to further investigate the role of oxygen-mediated and non-oxygen-mediated photoinactivation mechanisms. S. aureus lost culturability much faster in oxic systems than in anoxic systems, indicating an important role for oxygen in photodecay mechanisms. S. aureus cell membranes were damaged by sunlight exposure in anoxic systems but not in oxic systems, as measured by cell membrane permeability to propidium iodide. After sunlight exposure, S. aureus increased expression of a gene coding for methionine sulfoxide reductase after 12 h of sunlight exposure in the oxic system and after 6 h of sunlight exposure in the anoxic system, suggesting that methionine sulfoxide reductase is an important enzyme for defense against both oxygen-dependent and oxygen-independent photostresses. This research highlights the importance of oxygen in bacterial photoinactivation in environmentally relevant systems and the complexity of the bacterial photostress response with respect to cell structure and transcriptional regulation.IMPORTANCEStaphylococcus aureus is a pathogenic bacterium that causes gastrointestinal, respiratory, and skin infections. In severe cases, S. aureus infection can lead to life

  4. Cluster Chemistry

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    @@ Cansisting of eight scientists from the State Key Laboratory of Physical Chemistry of Solid Surfaces and Xiamen University, this creative research group is devoted to the research of cluster chemistry and creation of nanomaterials.After three-year hard work, the group scored a series of encouraging progresses in synthesis of clusters with special structures, including novel fullerenes, fullerene-like metal cluster compounds as well as other related nanomaterials, and their properties study.

  5. Connecting Remote Clusters with ATM

    Energy Technology Data Exchange (ETDEWEB)

    Hu, T.C.; Wyckoff, P.S.

    1998-10-01

    Sandia's entry into utilizing clusters of networked workstations is called Computational Plant or CPlant for short. The design of CPlant uses Ethernet to boot the individual nodes, Myrinet to communicate within a node cluster, and ATM to connect between remote clusters. This SAND document covers the work done to enable the use of ATM on the CPlant nodes in the Fall of 1997.

  6. Photodegradation of 2,4-Dichlorophenol in Aqueous Systems under Simulated and Natural Sunlight

    Directory of Open Access Journals (Sweden)

    Dorota Gryglik

    2016-01-01

    Full Text Available The work presents results of studies on 2,4-dichlorophenol (2,4-DCP degradation in aqueous solutions using photochemically initiated processes by simulated and natural sunlight. A number of possible substrate photodegradation routes were investigated, by both direct photolysis and photosensitized oxidation process. The major role of singlet oxygen in 2,4-DCP photodegradation was proved. Rose Bengal and derivatives of porphine and phthalocyanine were used as sensitizers. The influences of various process parameters on the reaction rate were investigated. On the basis of experimental data reaction rate constants of 2,4-DCP photosensitized oxidation were determined. The possibility of using natural sunlight to degrade 2,4-DCP in water in the middle latitudes was stated. The acute toxicity bioassay was conducted with the marine bacterium Vibrio fischeri as a bioluminescent indicator. The obtained results encourage further research on this process.

  7. Formation of Silicon Carbide Using Volcanic Ash as Starting Material and Concentrated Sunlight as Energy Resource

    Directory of Open Access Journals (Sweden)

    Kensuke Nishioka

    2015-01-01

    Full Text Available SiC was formed using volcanic ash as starting material and concentrated sunlight as energy resource. The solar furnace was composed of two parts: Fresnel lens and reacting furnace. The reacting furnace was composed of a cylindrical vacuum chamber and quartz glass plate functioning to guide the concentrated sunlight into the furnace and was placed at the focal point of the Fresnel lens. The sample was made from the mixture of silica formed from volcanic ash and graphite and placed in the carbon crucible inside the reacting furnace. The temperature in the carbon crucible reached more than 1500°C. After the reaction using concentrated light, β-SiC was formed. The weight % of formed SiC was 90.5%.

  8. Sensitized photoelectrolysis of water with sunlight. Final report, June 1, 1977-December 31, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, A.K.; Maruska, H.P.

    1978-12-01

    A study was made of solar driven water photoelectrolysis cells employing semiconductor electrodes. An extensive review of the literature was undertaken, and the three major problem areas for these devices were identified: corrosion, poor sunlight absorption, and external bias requirement. Although many semiconductors had been tested, none had proven free of all three defects. Two approaches were thus followed for the experimental studies: impurity sensitization of wide band gap stable oxides, and heterostructure formation between unstable sunlight absorbers and corrosion resistant oxides. Water decomposition was achieved with visible light excitation of Cr-doped TiO/sub 2/. Transport properties were studies for TiO/sub 2/ and SrTiO/sub 3/ electrodes doped with V, Cr, Mn, Fe, Co, and Ni. The correlation between bias requirement and electron affinity of oxides was identified. Performance of heterostructure electrodes was shown to be limited either by pin hole problems or by potential barriers between the valence bands.

  9. Sunlight-activated AlFeO3/TiO2 photocatalyst

    Institute of Scientific and Technical Information of China (English)

    YUAN; Zhihao; WANG; Yuhong; SUN; Yongchang; WANG; Jing; BIE; Lijian; DUAN; Yueqing

    2006-01-01

    A nanocomposite photocatalyst composed of AlFeO3 and TiO2 is prepared, and characterized through X-ray diffraction. Application of the nanocomposite for the photodegradations of eosin dye and methyl orange gives an improved photoactivity compared with TiO2-only nanomaterials. The optimal concentration of AlFeO3 in the composite is about 1.0 wt% under UV excitation, and 9.0 wt% under sunlight excitation for the improved photoactivity. Furthermore, this nanocomposite is more active for eosin photodegradation if natural sunlight rather than UV is used. This may be due to the reason that adding AlFeO3 nanoparticles into TiO2 matrix can promote the separation of photogenerated charge carriers, and extend the photoresponse of TiO2 toward visible region, which results in an increase in the solar energy utilization efficiency.

  10. Power Output Improvement of PV Module for Agricultural Use by Using Inexpensive Sunlight Concentrator

    Institute of Scientific and Technical Information of China (English)

    NISHIMURA Ryo

    2010-01-01

    PV modules are used as stand alone power sources for agricultural equipments such as lifting pumps in farms,where the power infrastructure is not yet improved.In order to expand the agricultural use of PV module,the cost of PV generation should be reduced.In this paper,the power output performance of a commercial PV module was improved by using a sunlight concentrator that could be assembled inexpensively and a simple sun-tracking method.

  11. Attitude of future healthcare provider towards vitamin D significance in relation to sunlight exposure.

    Science.gov (United States)

    Qureshi, Aysha Zia; Zia, Zubia; Gitay, Mehnaz Nuruddin; Khan, Muhammad Umair; Khan, Muhammad Saad

    2015-10-01

    Nature is the kindest of all to provide man with all the necessary components for a healthy life at easily accessible lengths. The deprivation arises with unawareness and lack of correct measures to extract the benefits. Medical education makes the youth aware of the numerous disorders and diseases, as well as their preventions and treatments. This awareness needs to be realized and implemented in the society, and it is not possible without the advisers acting on the same lines. Since doctors are the most trusted and their advice is adopted without much thought, it is extremely inevitable to analyze the attitude of medical students of various levels to understand the cause of their negligence toward their own deficiencies, the focus for this study being vitamin D (VD). A cross sectional descriptive study was done on undergraduate medical students of health profession from different universities of Pakistan to access the awareness regarding VD deficiency associated with sunlight. Informed consent was duly signed by each participant after which self-constructed questionnaire was provided to them and data are collected. SPSS 17 was used for Statistical analysis. Final students are well aware of VD significance, take food rich in VD but still suffer from fatigue and muscular pain. No treatment was taken for fatigue and muscular pain by majority of these sufferers and those who took treatment were VD supplement. The health sufferers were mostly those who avoided sunlight highlighting the role of VD in maintaining an active lifestyle as well as the significance of sunlight in maintaining VD levels. It can be concluded that in spite of awareness, the role of sunlight exposure and the proper time and duration of exposure cannot be ignored to create a healthy and active society.

  12. Sunlight decreased genotoxicity of azadirachtin on root tip cells of Allium cepa and Eucrosia bicolor.

    Science.gov (United States)

    Kwankua, W; Sengsai, S; Kuleung, C; Euawong, N

    2010-07-01

    Utilization of neem plant (Azadirachta indica A. Juss) extract for pest control in agriculture has raised concerns over contamination by the residues to the environment. Such residues, particularly azadirachtin (Aza), may cause deleterious effect to non-target organisms. This investigation was conducted to find out if Aza could be inactivated through exposures to sunlight. Activity of Aza was assessed as its ability to cause cytotoxic and genotoxic effects in the forms of nuclei abnormality and chromosome aberration as measured by mitotic index (MI) and mitotic aberration (MA). Varying concentrations of Aza were tested on Allium cepa and Eucrosia bicolor. It was found that the MI of all root tip meristematic cells of A. cepa and E. bicolor treated with 0.00005%, 0.00010%, 0.00015%, and 0.00020% (w/v) Aza-containing neem extract for 24h, were significantly lower than the controls. Complementary to the lower levels of MI, the Aza-treated groups showed higher MA levels in all cases investigated. Furthermore, the decreasing levels of MI and the increasing levels of MA related well with the increasing concentration of Aza. Microscopic examination of root tip meristematic cells revealed that the anomaly found most often were mitotic disturbances and chromosomal bridges. Exposures of 0.00020% (w/v) Aza to sunlight for 3 days and 7 days decreased Aza ability to induce cytotoxicity and genotoxicity, both in terms of MI and MA, to root tip meristematic cells in A. cepa and E. bicolor. Photodegradation of Aza upon exposure to direct sunlight was confirmed by HPLC. The study implicates that Aza would unlikely cause long term deleterious effects to the environment since it would be inactivated by sunlight. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  13. Calculation of the optimum thickness of thermo-insulation for collectors of sunlight installations

    Directory of Open Access Journals (Sweden)

    Ermuratskii V.V.

    2005-12-01

    Full Text Available In the work the task of calculation of the optimum thickness of thermo-insulation for collectors of sunlight and accumulators of the heat is considered. The simplified model of calculation and the technique based on an estimation of efficiency of investment projects is offered. It is shown, that at calculation on the simplified model which are not taking into account financial streams, the overestimated values of thickness thermo-insulation turn out.

  14. Photo-induced toxicity of titanium dioxide nanoparticles to Daphnia magna under natural sunlight.

    Science.gov (United States)

    Mansfield, C M; Alloy, M M; Hamilton, J; Verbeck, G F; Newton, K; Klaine, S J; Roberts, A P

    2015-02-01

    Titanium dioxide nanoparticles (TiO2 NP) are one of the most abundantly utilized nanoparticles in the world. Studies have demonstrated the ability of the anatase crystal of TiO2 NP to produce reactive oxygen species (ROS) in the presence of ultraviolet radiation (UVR), a co-exposure likely to occur in aquatic ecosystems. The goal of this study was to examine the photo-induced toxicity of anatase TiO2 NP under natural sunlight to Daphnia magna. D. magna were exposed to a range of UVR intensities and anatase TiO2 concentrations in an outdoor exposure system using the sun as the source of UVR. Different UVR intensities were achieved using UVR opaque and transparent plastics. AnataseTiO2-NP demonstrated the reciprocal relationship seen in other phototoxic compounds such as polycyclic aromatic hydrocarbons (PAHs) at higher UVR treatments. The calculated 8h LC50 of anatase TiO2 NP was 139 ppb under full intensity ambient natural sunlight, 778 ppb under 50% natural sunlight, and >500 ppm under 10% natural sunlight. Mortality was also compared between animals allowed to accumulate a body burden of anatase TiO2 for 1h and organisms whose first exposure to anatase TiO2 aqueous suspensions occurred under UVR. A significantly greater toxic effect was observed in aqueous, low body burden suspensions than that of TiO2 1h body burdens, which is dissimilar from the model presented in PAHs. Anatase TiO2 presents a unique photo-induced toxic model that is different than that of established phototoxic compounds.

  15. Multiple scattering of polarized light in planetary atmospheres. II - Sunlight reflected by terrestrial water clouds.

    Science.gov (United States)

    Hansen, J. E.

    1971-01-01

    The intensity and polarization of sunlight reflected by terrestrial water clouds are computed with the doubling method. The calculations illustrate that this method can be effectively used in problems involving strongly anisotropic phase matrices. The method can, therefore, be used to derive information about planetary clouds, including those of the earth, from polarimetric observations. The results of the computations indicate that the polarization is more sensitive than the intensity to cloud microstructure, such as particle size and shape.

  16. Highly Branched Sn-Doped ZnO Nanostructures for Sunlight Driven Photocatalytic Reactions

    Directory of Open Access Journals (Sweden)

    Yangyang Liu

    2014-01-01

    Full Text Available Ultralong, highly branched Sn-doped zinc oxide (ZnO nanostructures were fabricated using a simple substrate-free chemical vapor deposition (CVD method. The nanostructures exhibited efficient photocatalytic activities in degradation of methylene blue (MB under natural sunlight. 100% of MB with the concentration of 10 mg/L could be completely removed within 36 minutes. Possible reasons for the enhanced photocatalytic effect were analyzed.

  17. Highly Branched Sn-Doped ZnO Nanostructures for Sunlight Driven Photocatalytic Reactions

    OpenAIRE

    2014-01-01

    Ultralong, highly branched Sn-doped zinc oxide (ZnO) nanostructures were fabricated using a simple substrate-free chemical vapor deposition (CVD) method. The nanostructures exhibited efficient photocatalytic activities in degradation of methylene blue (MB) under natural sunlight. 100% of MB with the concentration of 10 mg/L could be completely removed within 36 minutes. Possible reasons for the enhanced photocatalytic effect were analyzed.

  18. The Photocatalytic Activity of TiO2-Zeolite Composite for Degradation of Dye Using Synthetic UV and Jeddah Sunlight

    Directory of Open Access Journals (Sweden)

    Laila M. Al-Harbi

    2015-01-01

    Full Text Available In this research different composites of impregnated TiO2 with LTA or FAU zeolites were used as different weight% ratio for photodegradation of organic dye. Normal laboratory UV-lamps were used as a source of UV irradiation. In addition a setup of system of mirrors was used to collect real Jeddah sunlight. A comparison of UV and real sunlight photodegradation activity showed that the real sunlight enhances new centers of active sites exhibiting higher catalytic activity than that of UV irradiated samples.

  19. Clustered regression with unknown clusters

    CERN Document Server

    Barman, Kishor

    2011-01-01

    We consider a collection of prediction experiments, which are clustered in the sense that groups of experiments ex- hibit similar relationship between the predictor and response variables. The experiment clusters as well as the regres- sion relationships are unknown. The regression relation- ships define the experiment clusters, and in general, the predictor and response variables may not exhibit any clus- tering. We call this prediction problem clustered regres- sion with unknown clusters (CRUC) and in this paper we focus on linear regression. We study and compare several methods for CRUC, demonstrate their applicability to the Yahoo Learning-to-rank Challenge (YLRC) dataset, and in- vestigate an associated mathematical model. CRUC is at the crossroads of many prior works and we study several prediction algorithms with diverse origins: an adaptation of the expectation-maximization algorithm, an approach in- spired by K-means clustering, the singular value threshold- ing approach to matrix rank minimization u...

  20. Sunlight-induced photochemical decay of oxidants in natural waters: implications in ballast water treatment.

    Science.gov (United States)

    Cooper, William J; Jones, Adam C; Whitehead, Robert F; Zika, Rod G

    2007-05-15

    The transport and discharge of ship ballast water has been recognized as a major vector for the introduction of invasive species. Chemical oxidants, long used in drinking water and wastewater treatment, are alternative treatment methods for the control of invasive species currently being tested for use on ships. One concern when a ballasted vessel arrives in port is the adverse effects of residual oxidant in the treated water. The most common oxidants include chlorine (HOCl/OCl-), bromine (HOBr/OBr-), ozone (03), hydrogen peroxide (H2O2), chlorine dioxide (ClO2), and monochloramine (NH2Cl). The present study was undertaken to evaluate the sunlight-mediated photochemical decomposition of these oxidants. Sunlight photodecomposition was measured at various pH using either distilled water or oligotrophic Gulf Stream water for specific oxidants. For selected oxidants, quantum yields at specific wavelengths were obtained. An environmental photochemical model, GCSOLAR, also provided predictions of the fate (sunlight photolysis half-lives) of HOCI/OCl-, HOBr/OBr-, ClO2, and NH2Cl for two different seasons at latitude 40 degrees and in water with two different concentrations of chromophoric dissolved organic matter. These data are useful in assessing the environmental fate of ballast water treatment oxidants if they were to be discharged in port.

  1. Spore sensitivity to sunlight and freezing can restrict dispersal in wood-decay fungi.

    Science.gov (United States)

    Norros, Veera; Karhu, Elina; Nordén, Jenni; Vähätalo, Anssi V; Ovaskainen, Otso

    2015-08-01

    Assessment of the costs and benefits of dispersal is central to understanding species' life-history strategies as well as explaining and predicting spatial population dynamics in the changing world. While mortality during active movement has received much attention, few have studied the costs of passive movement such as the airborne transport of fungal spores. Here, we examine the potential of extreme environmental conditions to cause dispersal mortality in wood-decay fungi. These fungi play a key role as decomposers and habitat creators in forest ecosystems and the populations of many species have declined due to habitat loss and fragmentation. We measured the effect of simulated solar radiation (including ultraviolet A and B) and freezing at -25°C on the spore germinability of 17 species. Both treatments but especially sunlight markedly reduced spore germinability in most species, and species with thin-walled spores were particularly light sensitive. Extrapolating the species' laboratory responses to natural irradiance conditions, we predict that sunlight is a relevant source of dispersal mortality at least at larger spatial scales. In addition, we found a positive effect of spore size on spore germinability, suggesting a trade-off between dispersal distance and establishment. We conclude that freezing and particularly sunlight can be important sources of dispersal mortality in wood-decay fungi which can make it difficult for some species to colonize isolated habitat patches and habitat edges.

  2. Bait Formulations of Chlorophyllin against Infected/Uninfected Lymnaea acuminata in Red and Sunlight

    Directory of Open Access Journals (Sweden)

    Navneet Kumar

    2015-01-01

    Full Text Available Control of snail population is an important tool in fasciolosis control programme. In order to achive this objective the method of bait formulation containing an attractant and a molluscicide is an appropriate approach to ensure the death of host snail. Chlorophyllin bait pellets were prepared by addition of attractants starch (10 mM/serine (20 mM and Chlorophyllin 2% agar solution. These baits were used against host snail Lymnaea acuminata. The behavioral response of snail against attractant (starch/serine and chlorophyllin was examined in red and sunlight. The fraction of snail that was in contact with chlorophyllin bait in zone-3 was used as measure of attraction process. Infected snails were more attracted with red light+starch (57.7%. Uninfected snails were more attracted by red light+serine (58.0%. The molluscicidal activity of chlorophyllin against infected snails in red light (96h LC50-1.88% chlorophyllin in bait and sunlight (96h LC50-2.40% chlorophyllin in bait was more pronounced than uninfected snail in red light (96h LC50-1.76% Chlorophyllin in bait and sunlight (96h LC50-3.62% chlorophyllin in bait.

  3. Perfluorooctanoic acid degradation in the presence of Fe(III) under natural sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dandan [Beijing Key Laboratory of Water Resource and Environmental Engineering, China University of Geosciences, Beijing 100083 (China); Xiu, Zongming [Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005 (United States); Liu, Fei [Beijing Key Laboratory of Water Resource and Environmental Engineering, China University of Geosciences, Beijing 100083 (China); Wu, Gang [Division of Hematology, Department of Internal Medicine, University of Texas-Medical School at Houston, Houston, TX 77030 (United States); Adamson, Dave; Newell, Charles [GSI Environmental Inc., Houston, TX 77098 (United States); Vikesland, Peter [Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061 (United States); Tsai, Ah-Lim [Division of Hematology, Department of Internal Medicine, University of Texas-Medical School at Houston, Houston, TX 77030 (United States); Alvarez, Pedro J., E-mail: alvarez@rice.edu [Department of Civil and Environmental Engineering, Rice University, Houston, TX 77005 (United States)

    2013-11-15

    Highlights: • PFOA was photo-chemically decomposed in the presence of Fe(III) and natural sunlight. • An alternative reaction pathway involves hydroxyl radical as confirmed by EPR. • Common oxidant-persulfate increased PFOA defluorination extent. -- Abstract: Due to the high bond dissociation energy (BDE) of C-F bonds (116 kcal/mol), perfluorooctanoic acid (PFOA) is a highly recalcitrant pollutant. Herein, we demonstrate a novel method to decompose PFOA in the presence of sunlight and ferric iron (Fe(III)). Under such conditions, 97.8 ± 1.7% of 50 μM PFOA decomposed within 28 days into shorter-chain intermediates and fluoride (F{sup −}), with an overall defluorination extent of 12.7 ± 0.5%. No PFOA was removed under visible light, indicating that UV radiation is required for PFOA decomposition. Spectroscopic analysis indicates that the decomposition reaction is likely initiated by electron-transfer from PFOA to Fe(III), forming Fe(II) and an unstable organic carboxyl radical. An alternative mechanism for the formation of this organic radical involves hydroxyl radicals, detected by electron paramagnetic resonance (EPR). The observation that PFOA can be degraded by Fe(III) under solar irradiation provides mechanistic insight into a possibly overlooked natural attenuation process. Because Fe(III) is abundant in natural waters and sunlight is essentially free, this work represents a potentially important step toward the development of simple and inexpensive remediation strategies for PFOA-contaminated water.

  4. Colour Changes Evaluation of Freshly Cut Alder Veneers Under the Influence of Indoor Sunlight

    Directory of Open Access Journals (Sweden)

    Emilia Adela SALCA

    2011-03-01

    Full Text Available The paper presents an experimental study concerning the colour changes occurred on the surfaces ofblack alder veneers (Alnus glutinosa, obtained from a freshly cut (not treated log, after their exposure tosunlight and darkness, for 1 and 3 months, under indoor conditions.A Chroma Meter Konika Minolta CR-410 device was used for colour measurement.The colorimetric coordinates were recorded before and after the exposure, according to ISO 7724-2.The results highlight a significant decrease of colour lightness, right after the first month of sunlight exposure.The a* and b* colour coordinates showed an increasing tendency with increasing exposure time, whichsignifies a colour darkening under sunlight radiation that penetrates the window glass. Colour differenceswere noticed right after the first month of sunlight exposure, while under darkness conditions, a relativecolour constancy was noticed, the colour changes being less pronounced, but yet perceptible by the humaneye.The study results complete the colorimetric database of veneers used in furniture industry, but theyalso contribute to the rehabilitation of black alder as a wood species with a real potential of use in furnitureindustry.

  5. Modified optical fiber daylighting system with sunlight transportation in free space.

    Science.gov (United States)

    Vu, Ngoc-Hai; Pham, Thanh-Tuan; Shin, Seoyong

    2016-12-26

    We present the design, optical simulation, and experiment of a modified optical fiber daylighting system (M-OFDS) for indoor lighting. The M-OFDS is comprised of three sub-systems: concentration, collimation, and distribution. The concentration part is formed by coupling a Fresnel lens with a large-core plastic optical fiber. The sunlight collected by the concentration sub-system is propagated in a plastic optical fiber and then collimated by the collimator, which is a combination of a parabolic mirror and a convex lens. The collimated beam of sunlight travels in free space and is guided to the interior by directing flat mirrors, where it is diffused uniformly by a distributor. All parameters of the system are calculated theoretically. Based on the designed system, our simulation results demonstrated a maximum optical efficiency of 71%. The simulation results also showed that sunlight could be delivered to the illumination destination at distance of 30 m. A prototype of the M-OFDS was fabricated, and preliminary experiments were performed outdoors. The simulation results and experimental results confirmed that the M-OFDS was designed effectively. A large-scale system constructed by several M-OFDSs is also proposed. The results showed that the presented optical fiber daylighting system is a strong candidate for an inexpensive and highly efficient application of solar energy in buildings.

  6. Improved Flexible Transparent Conductive Electrodes based on Silver Nanowire Networks by a Simple Sunlight Illumination Approach

    Science.gov (United States)

    Kou, Pengfei; Yang, Liu; Chang, Cheng; He, Sailing

    2017-01-01

    Silver nanowire (Ag NW) networks have attracted wide attention as transparent electrodes for emerging flexible optoelectronics. However, the sheet resistance is greatly limited by large wire-to-wire contact resistances. Here, we propose a simple sunlight illumination approach to remarkably improve their electrical conductivity without any significant degradation of the light transmittance. Because the power density is extremely low (0.1 W/cm2, 1-Sun), only slight welding between Ag NWs has been observed. Despite this, a sheet resistance of <20 Ω/sq and transmittance of ~87% at wavelength of 550 nm as well as excellent mechanical flexibility have still been achieved for Ag NW networks after sunlight illumination for 1 hour or longer, which are significant upgrades over those of ITO. Slight plasmonic welding together with the associated self-limiting effect has been investigated by numerical simulations and further verified experimentally through varied solar concentrations. Due to the reduced resistance, high-performance transparent film heaters as well as efficient defrosters have been demonstrated, which are superior to the previously-reported Ag NW based film heaters. Since the sunlight is environmentally friendly and easily available, sophisticated or expensive facilities are not necessary. Our findings are particularly meaningful and show enormous potential for outdoor applications. PMID:28169343

  7. Chemically derived luminescent graphene oxide nanosheets and its sunlight driven photocatalytic activity against methylene blue dye

    Science.gov (United States)

    Kumar, Sumeet; Kumar, Ashok

    2016-12-01

    In the present work, graphene oxide (GO) nanosheets (NSs) have been synthesized with precise control over their thickness and molecular structure. The existence of oxygen containing functional groups on GO NSs through chemical treatment confers remarkable optical properties on GO. XRD, TEM, Raman and FTIR techniques were used to confirm the phase and degree of oxidation, morphology, structural information and chemical structure of the synthesized GO NSs. UV-Vis. spectroscopy was employed to study the optical absorption properties of the synthesized GO NSs. The excitation wavelength dependent PL measurements of the synthesized GO NSs were carried out which could be useful for the design and development of GO based next generation optoelectronic devices. The most fascinating luminescent property of synthesized GO NSs is that its luminescence peak position can be easily tuned by only varying the excitation wavelength without significant changes in its size and chemical composition. In order to study the photocatalytic degradation of methylene blue (MB) dye using GO NSs as a photocatalyst, a sunlight driven photocatalytic activity has been performed. The degradation rate of MB dye becomes fast when GO NSs are added to the dye solution. The photodegradation efficiency of GO NSs is calculated to be 60%. The present results indicate that synthesized GO NSs can be used as sunlight active photocatalyst. The optimistic response to sunlight irradiation validates the potential of GO NSs in solar energy conversion.

  8. An MFC capable of regenerating the cathodic electron acceptor under sunlight

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A renewable MFC (microbial fuel cell) cathode was used in this study because the iodide ion could react with oxygen to generate triiodide under natural sunlight.The feasibility of the regeneration of triiodide ion under natural sunlight and the effect of the regenerated triiodide ion concentration on the MFC performance were studied.The results showed that the power density of the MFC using triiodide ion as cathodic electron acceptor was significantly higher than that of using ferricyanate,and that the iodide ion can be oxidized to triiodide ion by oxygen in air at the expense of natural sunlight.In addition,it was obvious from the experimental results that the MFC performance was improved with the increase of the triiodide concentration,indicating that the concentration of triiodide ion had a critical effect on the MFC performance.The linear sweep voltammetry (LSV) curves for the electro-reduction of triiodide ion on the carbon paper were obtained and the results suggested that the diffusion process of triiodide ions to cathode was the control factor for the MFC performance.

  9. Combined Application of Natural Sunlight and Hydrogen peroxide on the Removal of Harmful Cyanobacteria

    Science.gov (United States)

    Wang, D. H.; Li, L.; Zhu, C. W.; Wang, Z. Y.; Xie, P.

    2017-08-01

    This study provides an efficient and environmentally friendly advanced oxidation technique involving the combined application of natural sunlight and hydrogen peroxide for the removal of harmful cyanobacteria from lakes and reservoirs. In this paper, we collected water samples from Taihu Lake (Wuxi, China) in August 2016 when cyanobacterial blooms had occurred and then performed an outdoor experiment. Hydrogen peroxide at 0.6 mM had no obvious effect on the cyanobacterial inactivation in the dark, even stimulating cyanobacterial growth to some extent. Cyanobacteria were inactivated by higher concentrations of hydrogen peroxide (1.0 mM) in the dark, as well as 0.4 mM hydrogen peroxide under sunlight irradiation, indicating that natural sunlight significantly enhanced the effect of hydrogen peroxide on the removal of cyanobacteria. An experiment involving Pseudanabaena sp. (a harmful species) led to similar conclusions as the study using algae attained from Taihu Lake. This study provides a practical and effective method for controlling harmful cyanobacteria in natural water bodies.

  10. Photolysis of brominated flame retardants in textiles exposed to natural sunlight.

    Science.gov (United States)

    Kajiwara, Natsuko; Desborough, Jennifer; Harrad, Stuart; Takigami, Hidetaka

    2013-03-01

    Photolytic transformation profiles of technical hexabromocyclododecane (HBCD) and technical decabromodiphenyl ether (DecaBDE) in flame-retarded textiles exposed to natural sunlight were compared. Textiles that contained approximately 4% HBCDs by weight showed no substantial loss of any of the HBCD diastereomers during the entire exposure period (371 days), indicating that they were resistant to sunlight, that is, that debromination and isomerization of HBCD diastereomers did not occur under the experimental conditions. Exposure of a textile treated with technical DecaBDE resulted in the formation of polybrominated dibenzofurans (PBDFs) as products of photodecomposition of polybrominated diphenyl ethers present in the technical DecaBDE. After 329 days of exposure, the total PBDF concentration reached a maximum of 27 000 ng g(-1), which was approximately 10 times the initial concentration. During the experiment, di- to hexa-BDF congener concentrations increased continuously. Although the concentrations of PBDFs in the textiles were 4–5 orders of magnitude lower than the concentrations of polybrominated diphenyl ethers, it is important to note that PBDFs were formed as a result of sunlight exposure during normal use of products treated with technical DecaBDE.

  11. Spectroscopic properties of Er doped and Er, Nd codoped fluoride glasses under simulated sunlight illumination

    Science.gov (United States)

    Mizuno, Shintaro; Ito, Hiroshi; Hasegawa, Kazuo; Kawai, Hiroyuki; Nasu, Hiroyuki; Hughes, Mark A.; Suzuki, Takenobu; Ohishi, Yasutake

    2011-10-01

    We investigated the fluorescence characteristics of Er codoped Nd doped ZBLAN glasses proposed for solar pumped fiber laser (SPFL) under simulated sunlight. Er is used as a sensitizer because it absorbs a part of the ultraviolet and visible light where is no absorption of Nd. Under simulated sunlight illumination, Er singly doped fluoride glass displayed four emission bands with peaks at 550, 848, 977 and 1533 nm attributed to the 4S 3/2- 4I 15/2, 4S 3/2- 4I 13/2, 4I 11/2- 4I 15/2 and 4I 13/2- 4I 15/2 electronic transitions of Er, respectively. The quantum efficiency measurement was carried out using an integrating sphere and under the simulated sunlight excitation showed a maximum of 73% for 0.5 mol.% of ErF 3 in ZBLAN glass. In Nd, Er codoped fluoride glass, the 1.05 μm emission of Nd was observed under 380 nm excitation what supposes the energy transfer from Er to Nd in ZBLAN glasses as Nd has no absorption at the wavelength. Er, Nd codoped fluoride glasses are promising as a sensitized laser media for solar pumped fiber lasers.

  12. Subspace clustering through attribute clustering

    Institute of Scientific and Technical Information of China (English)

    Kun NIU; Shubo ZHANG; Junliang CHEN

    2008-01-01

    Many recently proposed subspace clustering methods suffer from two severe problems. First, the algorithms typically scale exponentially with the data dimensionality or the subspace dimensionality of clusters. Second, the clustering results are often sensitive to input parameters. In this paper, a fast algorithm of subspace clustering using attribute clustering is proposed to over-come these limitations. This algorithm first filters out redundant attributes by computing the Gini coefficient. To evaluate the correlation of every two non-redundant attributes, the relation matrix of non-redundant attributes is constructed based on the relation function of two dimensional united Gini coefficients. After applying an overlapping clustering algorithm on the relation matrix, the candidate of all interesting subspaces is achieved. Finally, all subspace clusters can be derived by clustering on interesting subspaces. Experiments on both synthesis and real datasets show that the new algorithm not only achieves a significant gain of runtime and quality to find subspace clusters, but also is insensitive to input parameters.

  13. Cluster headaches.

    Science.gov (United States)

    Ryan, R E; Ryan, R E

    1989-12-01

    The patient with cluster headaches will be afflicted with the most severe type of pain that one will encounter. If the physician can do something to help this patient either by symptomatic or, more importantly, prophylactic treatment, he or she will have a most thankful patient. This type of headache is seen most frequently in men, and occurs in a cyclic manner. During an acute cycle, the patient will experience a daily type of pain that may occur many times per day. The pain is usually unilateral and may be accompanied by unilateral lacrimation, conjunctivitis, and clear rhinorrhea. Prednisone is the first treatment we employ. Patients are seen for follow-up approximately twice a week, and their medication is lowered in an appropriate manner, depending on their response to the treatment. Regulation of dosage has to be individualized, and when one reaches the lower dose such as 5 to 10 mg per day, the drug may have to be tapered more slowly, or even maintained at that level for a period of time to prevent further recurrence of symptoms. We frequently will use an intravenous histamine desensitization technique to prevent further attacks. We will give the patient an ergotamine preparation to use for symptomatic relief. As these patients often have headaches during the middle of the night, we will place the patient on a 2-mg ergotamine preparation to take prior to going to bed in the evening. This often works in a prophylactic nature, and prevents the nighttime occurrence of a headache. We believe that following these principles to make the accurate diagnosis and institute the proper therapy will help the practicing otolaryngologist recognize and treat patients suffering from this severe pain.

  14. Sunlight creates oxygenated species in water-soluble fractions of Deepwater horizon oil

    Energy Technology Data Exchange (ETDEWEB)

    Ray, Phoebe Z. [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States); Chen, Huan [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Podgorski, David C. [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Future Fuels Institute, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); McKenna, Amy M. [National High Magnetic Field Laboratory, Florida State University, 1800 East Paul Dirac Drive, Tallahassee, FL 32310-4005 (United States); Tarr, Matthew A., E-mail: mtarr@uno.edu [Department of Chemistry, University of New Orleans, New Orleans, LA 70148 (United States)

    2014-09-15

    Graphical abstract: Sunlight oxygenates petroleum. - Highlights: • Oxidation seen in water-soluble oil fraction after exposure to simulated sunlight. • Oxygen addition occurred across a wide range of carbon number and DBE. • Oil compounds were susceptible to addition of multiple oxygens to each molecule. • Results provide understanding of fate of oil on water after exposure to sunlight. - Abstract: In order to assess the impact of sunlight on oil fate, Macondo well oil from the Deepwater Horizon (DWH) rig was mixed with pure water and irradiated with simulated sunlight. After irradiation, the water-soluble organics (WSO) from the dark and irradiated samples were extracted and characterized by ultrahigh resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Liquid–liquid extraction yielded two fractions from dark and irradiated water/oil mixtures: acidic WSOs (negative-ion electrospray (ESI)), and base/neutral WSOs (positive-ion ESI) coupled to FT-ICR MS to catalog molecular-level transformations that occur to Macondo-derived WSOs after solar irradiation. Such direct measure of oil phototransformation has not been previously reported. The most abundant heteroatom class detected in the irradiated WSO acid fractions correspond to molecules that contain five oxygens (O{sub 5}), while the most abundant acids in the dark samples contain two oxygen atoms per molecule (O{sub 2}). Higher-order oxygen classes (O{sub 5}–O{sub 9}) were abundant in the irradiated samples, but <1.5% relative abundance in the dark sample. The increased abundance of higher-order oxygen classes in the irradiated samples relative to the dark samples indicates that photooxidized components of the Macondo crude oil become water-soluble after irradiation. The base/neutral fraction showed decreased abundance of pyridinic nitrogen (N{sub 1}) concurrent with an increased abundance of N{sub 1}O{sub x} classes after irradiation. The predominance of higher

  15. Why We Need More Nature at Work: Effects of Natural Elements and Sunlight on Employee Mental Health and Work Attitudes.

    Directory of Open Access Journals (Sweden)

    Mihyang An

    Full Text Available This study investigated the effects of natural elements and direct and indirect sunlight exposure on employee mental health and work attitudes. We recruited participants via an online panel from the United States and India, and analyzed data from 444 employees. Natural elements and sunlight exposure related positively to job satisfaction and organizational commitment, and negatively to depressed mood and anxiety. Direct sunlight was a dominant predictor of anxiety; indirect sunlight was a dominant predictor of depressed mood, job satisfaction, and organizational commitment. Natural elements buffered the relationship between role stressors and job satisfaction, depressed mood, and anxiety. We also found that depressed mood partially mediated the relationship between natural elements and job satisfaction. We discuss scientific and policy implications of these findings.

  16. Interacting effects of sunlight, agriculturally derived dissolved organic matter and reactive oxygen species on fecal indicator bacteria growth dynamics

    Science.gov (United States)

    Bacterial survival in agriculturally impacted surface waters is dependent on resource availability and also on potential resource transformations, mediated by biotic and abiotic processes. In this study, we focused on the effect of sunlight irradiated cattle fecal extract (CFE) a...

  17. Cluster functional renormalization group

    Science.gov (United States)

    Reuther, Johannes; Thomale, Ronny

    2014-01-01

    Functional renormalization group (FRG) has become a diverse and powerful tool to derive effective low-energy scattering vertices of interacting many-body systems. Starting from a free expansion point of the action, the flow of the RG parameter Λ allows us to trace the evolution of the effective one- and two-particle vertices towards low energies by taking into account the vertex corrections between all parquet channels in an unbiased fashion. In this work, we generalize the expansion point at which the diagrammatic resummation procedure is initiated from a free UV limit to a cluster product state. We formulate a cluster FRG scheme where the noninteracting building blocks (i.e., decoupled spin clusters) are treated exactly, and the intercluster couplings are addressed via RG. As a benchmark study, we apply our cluster FRG scheme to the spin-1/2 bilayer Heisenberg model (BHM) on a square lattice where the neighboring sites in the two layers form the individual two-site clusters. Comparing with existing numerical evidence for the BHM, we obtain reasonable findings for the spin susceptibility, the spin-triplet excitation energy, and quasiparticle weight even in coupling regimes close to antiferromagnetic order. The concept of cluster FRG promises applications to a large class of interacting electron systems.

  18. [Behaviors related to sunlight exposure versus protection in a random population sample from 15 Brazilian State capitals and the Federal District, 2002-2003].

    Science.gov (United States)

    Szklo, André Salem; Almeida, Liz Maria de; Figueiredo, Valeska; Lozana, José de Azevedo; Azevedo e Silva Mendonça, Gulnar; Moura, Lenildo de; Szklo, Moysés

    2007-04-01

    This article examines region-specific relations between prevalence of protection against sunlight and socio-demographic and behavioral variables in Brazil. Data were derived from a cross-sectional population-based random sample. Information on sunlight exposure was available for a total of 16,999 individuals 15 years and older. Comparing the North and South of Brazil, crude differences between women and men in the use of "sunscreen" and "protective headwear" were +10.9% (95%CI: 7.1; 14.6) and -11.6% (95%CI: -17.0; -6.3) in the North and +21.3% (95%CI: 17.7; 24.9) and -16.0% (95%CI: -20.2; -12.5) in the South. Adjusted differences by selected variables confirmed that women use more sunscreen protection and less headwear protection as compared to men in both the North and South, but the difference was not homogeneous by region (interaction term p value < 0.05).

  19. Sunlight exposure or vitamin D supplementation for vitamin D-deficient non-western immigrants: a randomized clinical trial.

    Science.gov (United States)

    Wicherts, I S; Boeke, A J P; van der Meer, I M; van Schoor, N M; Knol, D L; Lips, P

    2011-03-01

    Vitamin D deficiency is very common in non-western immigrants. In this randomized clinical trial, vitamin D 800 IU/day or 100,000 IU/3 months were compared with advised sunlight exposure. Vitamin D supplementation was more effective than advised sunlight exposure in improving vitamin D status and lowering parathyroid hormone levels. Vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] sunlight exposure. To determine whether the effect of vitamin D(3) supplementation (daily 800 IU or 100,000 IU/3 months) or sunlight exposure advice is similar with regard to serum 25(OH)D and parathyroid hormone (PTH) concentrations. Randomized clinical trial in 11 general practices in The Netherlands. Non-western immigrants, aged 18-65 years (n = 232) and serum 25(OH)D sunlight exposure for 6 months (March-September). Blood samples were collected at baseline, during treatment (3 months, 6 months), and at follow-up (12 months). Statistical analysis was performed with multilevel regression modelling. The intention-to-treat analysis included 211 persons. Baseline serum 25(OH)D was 22.5 ± 11.1 nmol/l. After 6 months, mean serum 25(OH)D increased to 53 nmol/l with 800 IU/day, to 50.5 nmol/l with 100,000 IU/3 months, and to 29.1 nmol/l with advised sunlight exposure (supplementation vs sunshine p sunlight group (p sunlight exposure for treating vitamin D deficiency in non-western immigrants.

  20. Sunlight-stimulated phenylalanine ammonia-lyase (PAL) activity and anthocyanin accumulation in exocarp of ‘Mahajanaka’ mango

    OpenAIRE

    Kobkiat Saengnil

    2011-01-01

    The activity of phenylalanine ammonia-lyase (PAL) required for anthocyanin synthesis was stimulated by sunlight exposure resulting in the development of red colour in ‘Mahajanaka’ mango exocarp, which occurred only on the sunlight-exposed side of the fruit. The accumulation of anthocyanin was concurrent with the increase in PAL activity in the mature stage of the fruit. The exposed side of the fruit had higher PAL activity, endogenous sugar content, and anthocyanin accumulation than the unexp...

  1. Cluster editing

    DEFF Research Database (Denmark)

    Böcker, S.; Baumbach, Jan

    2013-01-01

    . The problem has been the inspiration for numerous algorithms in bioinformatics, aiming at clustering entities such as genes, proteins, phenotypes, or patients. In this paper, we review exact and heuristic methods that have been proposed for the Cluster Editing problem, and also applications......The Cluster Editing problem asks to transform a graph into a disjoint union of cliques using a minimum number of edge modifications. Although the problem has been proven NP-complete several times, it has nevertheless attracted much research both from the theoretical and the applied side...

  2. Weighted Clustering

    CERN Document Server

    Ackerman, Margareta; Branzei, Simina; Loker, David

    2011-01-01

    In this paper we investigate clustering in the weighted setting, in which every data point is assigned a real valued weight. We conduct a theoretical analysis on the influence of weighted data on standard clustering algorithms in each of the partitional and hierarchical settings, characterising the precise conditions under which such algorithms react to weights, and classifying clustering methods into three broad categories: weight-responsive, weight-considering, and weight-robust. Our analysis raises several interesting questions and can be directly mapped to the classical unweighted setting.

  3. Cluster analysis

    CERN Document Server

    Everitt, Brian S; Leese, Morven; Stahl, Daniel

    2011-01-01

    Cluster analysis comprises a range of methods for classifying multivariate data into subgroups. By organizing multivariate data into such subgroups, clustering can help reveal the characteristics of any structure or patterns present. These techniques have proven useful in a wide range of areas such as medicine, psychology, market research and bioinformatics.This fifth edition of the highly successful Cluster Analysis includes coverage of the latest developments in the field and a new chapter dealing with finite mixture models for structured data.Real life examples are used throughout to demons

  4. A sunlight-induced method for rapid biosynthesis of silver nanoparticles using an Andrachnea chordifolia ethanol extract

    Science.gov (United States)

    Karimi Zarchi, A. A.; Mokhtari, N.; Arfan, M.; Rehman, T.; Ali, M.; Amini, M.; Faridi Majidi, R.; Shahverdi, A. R.

    2011-05-01

    In this study a sunlight-induced method for rapid synthesis of silver nanoparticles using an ethanol extract of Andrachnea chordifolia is described. The silver nitrate solutions (1 mM) containing the ethanol extract of Andrachnea chordifolia were irradiated by both sunlight radiation and by sunlight radiation passed through different colored filters (red, yellow or green). The smallest size of silver nanoparticles was obtained when a silver ion solution was irradiated for 5 minutes by direct sunlight radiation. Further examination of the shape and size and of the surface chemistry of these biogenic silver nanoparticles, which were prepared under sunlight radiation, was carried out using transmission electron microscopy and infrared spectroscopy, respectively. Transmission electron microscopy images show spherical particles with an average size of 3.4 nm. Hydroxyl residues were also detected on the surface of these biogenic silver nanoparticles fabricated using plant extract of Andrachnea chordifolia under sunlight radiation. Our study on the reduction of silver ions by this plant extract in darkness shows that the synthesis process can take place under dark conditions at much longer incubations (48 hours). Larger silver polydispersed nanoparticles ranging in size from 3 to 30 nm were obtained when the silver ions were treated with the ethanol extract of Andrachnea chordifolia under dark conditions for 48 hours.

  5. A sunlight-induced method for rapid biosynthesis of silver nanoparticles using an Andrachnea chordifolia ethanol extract

    Energy Technology Data Exchange (ETDEWEB)

    Karimi Zarchi, A.A.; Faridi Majidi, R. [Tehran University of Medical Sciences, Department of Nanomedicine, School of Advanced Medical Technologies, Tehran (Iran, Islamic Republic of); Mokhtari, N.; Shahverdi, A.R. [Tehran University of Medical Sciences, Department of Pharmaceutical Biotechnology and Medicinal Plants Research Center, Faculty of Pharmacy, Tehran (Iran, Islamic Republic of); Arfan, M.; Rehman, T.; Ali, M. [University of Peshawar, Institute of Chemical Sciences, Peshawar, Khyber Pakhtoonkhwa (Pakistan); Amini, M. [Tehran University of Medical Sciences, Department of Medicinal Chemistry, Faculty of Pharmacy, Tehran (Iran, Islamic Republic of)

    2011-05-15

    In this study a sunlight-induced method for rapid synthesis of silver nanoparticles using an ethanol extract of Andrachnea chordifolia is described. The silver nitrate solutions (1 mM) containing the ethanol extract of Andrachnea chordifolia were irradiated by both sunlight radiation and by sunlight radiation passed through different colored filters (red, yellow or green). The smallest size of silver nanoparticles was obtained when a silver ion solution was irradiated for 5 minutes by direct sunlight radiation. Further examination of the shape and size and of the surface chemistry of these biogenic silver nanoparticles, which were prepared under sunlight radiation, was carried out using transmission electron microscopy and infrared spectroscopy, respectively. Transmission electron microscopy images show spherical particles with an average size of 3.4 nm. Hydroxyl residues were also detected on the surface of these biogenic silver nanoparticles fabricated using plant extract of Andrachnea chordifolia under sunlight radiation. Our study on the reduction of silver ions by this plant extract in darkness shows that the synthesis process can take place under dark conditions at much longer incubations (48 hours). Larger silver polydispersed nanoparticles ranging in size from 3 to 30 nm were obtained when the silver ions were treated with the ethanol extract of Andrachnea chordifolia under dark conditions for 48 hours. (orig.)

  6. Fuzzy Clustering

    DEFF Research Database (Denmark)

    Berks, G.; Keyserlingk, Diedrich Graf von; Jantzen, Jan

    2000-01-01

    A symptom is a condition indicating the presence of a disease, especially, when regarded as an aid in diagnosis.Symptoms are the smallest units indicating the existence of a disease. A syndrome on the other hand is an aggregate, set or cluster of concurrent symptoms which together indicate...... and clustering are the basic concerns in medicine. Classification depends on definitions of the classes and their required degree of participant of the elements in the cases' symptoms. In medicine imprecise conditions are the rule and therefore fuzzy methods are much more suitable than crisp ones. Fuzzy c......-mean clustering is an easy and well improved tool, which has been applied in many medical fields. We used c-mean fuzzy clustering after feature extraction from an aphasia database. Factor analysis was applied on a correlation matrix of 26 symptoms of language disorders and led to five factors. The factors...

  7. Formation of rutile fasciculate zone induced by sunlight irradiation at room temperature and its hemocompatibility

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xuan-Hui; Zheng, Xiang; Cheng, Yuan [School of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014 (China); Li, Guo-Hua, E-mail: nanozjut@zjut.edu.cn [School of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310014 (China); State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310014 (China); Research Center of Nanoscience and Technology, Zhejiang University of Technology, Hangzhou 310014 (China); Chen, Xiao-Ping, E-mail: chxp@zjut.edu.cn [School of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310014 (China); Zheng, Jian-Hui [School of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou 310014 (China)

    2013-08-01

    The fasciculate zone of phase pure rutile was fabricated under sunlight irradiation at room temperature, using titanium tetrachloride as a sole precursor. The crystal phase, morphology and microstructure, and optical absorption behavior of the samples were characterized by X-ray Diffraction, High-Resolution Transmission Electron Microscope (HRTEM) and UV–vis Diffuse Reflectance Spectra (DRS), respectively. XRD results show that the crystal phase of the sample is composed of rutile only, and a lattice distortion displays in the crystallite of the sample. HRTEM results show that the morphology of rutile particle is fasciculate zone constituted of nanoparticles with a diameter of 4–7 nm, and these particles grow one by one and step by step. The pattern of the selected area electron diffraction of the sample is Kikuchi type, which can be attributed to the predominant orientation growth of rutile nanoparticles along [001] induced by sunlight irradiation. DRS results show that the absorption threshold of the sample is 415 nm, corresponding to the band gap energy of 2.99 eV, which is lower than the band gap energy of rutile, 3.03 eV. Blood compatibility measurement shows that the sample has no remarkable effect on hemolytic and coagulation activity. The percent hemolysis of red blood cells is less than 5% even treated with a big dosage of the fasciculate rutile and under UV irradiation, and there are no obvious changes of plasma recalcification time after the rutile treatment. Thus, the novel structure of rutile fasciculate has low potential toxicity for blood and is hemocompatibility safe. Highlights: • A novel approach to fabricate the fasciculate zone of phase pure rutile • The fasciculate grows from a particle to nanorod and to fasciculate, step by step. • A preferred orientation growth induced by sunlight irradiation in the fasciculate • The rutile fasciculate is low toxicity for blood and is hemocompatibility safe.

  8. Technoeconomic analysis of different options for the production of hydrogen from sunlight, wind, and biomass

    Energy Technology Data Exchange (ETDEWEB)

    Mann, M.K.; Spath, P.L.; Amos, W.A. [National Renewable Energy Lab., Golden, CO (United States)

    1998-08-01

    To determine their technical and economic viability and to provide insight into where each technology is in its development cycle, different options to produce hydrogen from sunlight, wind, and biomass were studied. Additionally, costs for storing and transporting hydrogen were determined for different hydrogen quantities and storage times. The analysis of hydrogen from sunlight examined the selling price of hydrogen from two technologies: direct photoelectrochemical (PEC) conversion of sunlight and photovoltaic (PV)-generated electricity production followed by electrolysis. The wind analysis was based on wind-generated electricity production followed by electrolysis. In addition to the base case analyses, which assume that hydrogen is the sole product, three alternative scenarios explore the economic impact of integrating the PV- and wind-based systems with the electric utility grid. Results show that PEC hydrogen production has the potential to be economically feasible. Additionally, the economics of the PV and wind electrolysis systems are improved by interaction with the grid. The analysis of hydrogen from biomass focused on three gasification technologies. The systems are: low pressure, indirectly-heated gasification followed by steam reforming; high pressure, oxygen-blown gasification followed by steam reforming; and pyrolysis followed by partial oxidation. For each of the systems studied, the downstream process steps include shift conversion followed by hydrogen purification. Only the low pressure system produces hydrogen within the range of the current industry selling prices (typically $0.7--$2/kg, or $5--14/GJ on a HHV basis). A sensitivity analysis showed that, for the other two systems, in order to bring the hydrogen selling price down to $2/kg, negative-priced feedstocks would be required.

  9. Photoreactivity of carboxylated single-walled carbon nanotubes in sunlight: reactive oxygen species production in water.

    Science.gov (United States)

    Chen, Chia-Ying; Jafvert, Chad T

    2010-09-01

    Very limited information exists on transformation processes of carbon nanotubes in the natural aquatic environment. Because the conjugated pi-bond structure of these materials is efficient in absorbing sunlight, photochemical transformations are a potential fate process with reactivity predicted to vary with their diameter, chirality, number and type of defects, functionalization, residual metal catalyst and amorphous carbon content, and with the composition of the water, including the type and composition of materials that act to disperse them into the aqueous environment. In this study, the photochemical reactions involving colloidal dispersions of carboxylated single-walled carbon nanotubes (SWNT-COOH) in sunlight were examined. Production of reactive oxygen species (ROS) during irradiation occurs and is evidence for potential further phototransformation and may be significant in assessing their overall environmental impacts. In aerated samples exposed to sunlight or to lamps that emit light only within the solar spectrum, the probe compounds, furfuryl alcohol (FFA), tetrazolium salts (NBT2+ and XTT), and p-chlorobenzoic acid (pCBA), were used to indicate production of 1O2, O2.-, and .OH, respectively. All three ROS were produced in the presence of SWNT-COOH and molecular oxygen (3O2). 1O2 production was confirmed by observing enhanced FFA decay in deuterium oxide, attenuated decay of FFA in the presence of azide ion, and the lack of decay of FFA in deoxygenated solutions. Photogeneration of O2.- and .OH was confirmed by applying superoxide dismutase (SOD) and tert-butanol assays, respectively. In air-equilibrated suspensions, the loss of 0.2 mM FFA in 10 mg/L SWNT-COOH was approximately 85% after 74 h. Production of 1O2 was not dependent on pH from 7 to 11; however photoinduced aggregation was observed at pH 3.

  10. The ability of periorbitally applied antiglare products to improve contrast sensitivity in conditions of sunlight exposure.

    Science.gov (United States)

    DeBroff, Brian M; Pahk, Patricia J

    2003-07-01

    Sun glare decreases athletes' contrast sensitivity and impairs their ability to distinguish objects from background. Many commercial products claim to reduce glare but have not been proven effective in clinical studies. To determine whether glare-reducing products such as eye black grease and antiglare stickers reduce glare and improve contrast sensitivity during sunlight exposure. We tested 46 subjects for contrast sensitivity using a Pelli-Robson contrast chart. Each subject served as an internal control and then was randomized to either application of eye black grease, antiglare stickers, or petroleum jelly at the infraorbital rim. All testing was performed in conditions of unobstructed sunlight. Analysis of variance revealed a significant difference between eye black grease (mean +/- SD, Pelli-Robson value, 1.87 +/- 0.09 logMAR units) and antiglare stickers (1.75 +/- 0.14 logMAR units) in binocular testing (P =.02). No statistical difference was found between the groups in right eyes, left eyes, or in combined data from the right and left eyes. Paired t tests demonstrated a significant difference between control (mean +/- SD, 1.77 +/- 0.14 logMAR units) and eye black grease (1.87 +/- 0.09 logMAR units) in binocular testing (P =.04). There was also a significant difference between control (mean +/- SD, 1.65 +/- 0.05 logMAR units) and eye black grease (1.67 +/- 0.06 logMAR units) in combined data from the right and left eyes (P =.02). Eye black grease reduces glare and improves contrast sensitivity in conditions of sunlight exposure compared with the control and antiglare stickers in binocular testing.

  11. The genotoxic effects of DNA lesions induced by artificial UV-radiation and sunlight.

    Science.gov (United States)

    Schuch, André Passaglia; Menck, Carlos Frederico Martins

    2010-06-01

    Solar radiation sustains and affects all life forms on Earth. The increase in solar UV-radiation at environmental levels, due to depletion of the stratospheric ozone layer, highlights serious issues of social concern. This becomes still more dramatic in tropical and subtropical regions where radiation-intensity is still higher. Thus, there is the need to evaluate the harmful effects of solar UV-radiation on the DNA molecule as a basis for assessing the risks involved for human health, biological productivity and ecosystems. In order to evaluate the profile of DNA damage induced by this form of radiation and its genotoxic effects, plasmid DNA samples were exposed to artificial-UV lamps and directly to sunlight. The induction of cyclobutane pyrimidine dimer photoproducts (CPDs) and oxidative DNA damage in these molecules were evaluated by means of specific DNA repair enzymes. On the other hand, the biological effects of such lesions were determined through the analysis of the DNA inactivation rate and mutation frequency, after replication of the damaged pCMUT vector in an Escherichia coliMBL50 strain. The results indicated the induction of a significant number of CPDs after exposure to increasing doses of UVC, UVB, UVA radiation and sunlight. Interestingly, these photoproducts are those lesions that better correlate with plasmid inactivation as well as mutagenesis, and the oxidative DNA damages induced present very low correlation with these effects. The results indicated that DNA photoproducts play the main role in the induction of genotoxic effects by artificial UV-radiation sources and sunlight.

  12. The Sloan Nearby Cluster Weak Lensing Survey

    CERN Document Server

    Kubo, Jeffrey M; Hardin, Frances Mei; Kubik, Donna; Lawhorn, Kelsey; Lin, Huan; Nicklaus, Liana; Nelson, Dylan; Reis, Ribamar R R; Seo, Hee-Jong; Soares-Santos, Marcelle; Stebbins, Albert; Yunker, Tony

    2009-01-01

    We describe and present initial results of a weak lensing survey of nearby ($\\rm{z}\\lesssim0.1$) galaxy clusters in the Sloan Digital Sky Survey (SDSS). In this first study, galaxy clusters are selected from the SDSS spectroscopic galaxy cluster catalogs of \\citet{miller05} and \\citet{berlind06}. We report a total of seven individual low redshift cluster weak lensing measurements which include: A2048, A1767, A2244, A1066, A2199, and two clusters specifically identified with the C4 algorithm. Our program of weak lensing of nearby galaxy clusters in the SDSS will eventually reach $\\sim 200$ clusters, making it the largest weak lensing survey of individual galaxy clusters to date.

  13. Dispersed single-phase-step Michelson interferometer for Doppler imaging using sunlight.

    Science.gov (United States)

    Wan, Xiaoke; Ge, Jian

    2012-09-15

    A Michelson interferometer is dispersed with a fiber array-fed spectrograph, providing 59 Doppler sensing channels using sunlight in the 510-570 nm wavelength region. The interferometer operates at a single-phase-step mode, which is particularly advantageous in multiplexing and data processing compared to the phase-stepping mode of other interferometer spectrometer instruments. Spectral templates are prepared using a standard solar spectrum and simulated interferometer modulations, such that the correlation function with a measured 1D spectrum determines the Doppler shift. Doppler imaging of a rotating cylinder is demonstrated. The average Doppler sensitivity is ~12 m/s, with some channels reaching ~5 m/s.

  14. On the origin of the coherence of sunlight on the earth.

    Science.gov (United States)

    Sundaram, Sriram; Panigrahi, Prasanta K

    2016-09-15

    It is shown that the observed far-field behavior of sunlight on the earth's surface, located in the near-field region, is due to the small angular width it subtends at the center of the sun. The investigation of the angular behavior of the cross-spectral density function explicitly leads to Bessel-like far-zone behavior for a small angle without any restriction on the value of l. Our general analysis for the spherical source can be easily extended to other geometries.

  15. Influence of Sound Wave Stimulation on the Growth of Strawberry in Sunlight Greenhouse

    Science.gov (United States)

    Qi, Lirong; Teng, Guanghui; Hou, Tianzhen; Zhu, Baoying; Liu, Xiaona

    In this paper, we adopt the QGWA-03 plant audio apparatus to investigate the sound effects on strawberry in the leaf area, the photosynthetic characteristics and other physiological indexes. It was found that when there were no significant differences between the circumstances of the two sunlight greenhouses, the strawberry after the sound wave stimulation grew stronger than in the control and its leaf were deeper green, and shifted to an earlier time about one week to blossom and bear fruit. It was also found that the resistance of strawberry against disease and insect pest were enhanced. The experiment results show that sound wave stimulation can certainly promote the growth of plants.

  16. Carbon nanofibers, precious commodities from sunlight & CO2 to ameliorate global warming

    CERN Document Server

    Licht, Stuart

    2015-01-01

    This study introduces the high yield, electrolytic synthesis of carbon nanofibers, CNFs, directly from carbon dioxide. Production of a precious commodity such as CNFs from atmospheric carbon dioxide provides impetus to limit this greenhouse gas and mitigate the rate of climate change. CNFs are formed at high rate using inexpensive nickel and steel electrodes in molten electrolytes. The process is demonstrated as a scaled-up stand-alone electrolytic cell, and is also shown compatible with the STEP, solar thermal electrochemical process, using concentrated sunlight at high solar to electric efficiency to provide the heat and electrical energy to drive the CNF production.

  17. Sunlight-Induced Photochemical Degradation of Methylene Blue by Water-Soluble Carbon Nanorods

    Directory of Open Access Journals (Sweden)

    Anshu Bhati

    2016-01-01

    Full Text Available Water-soluble graphitic hollow carbon nanorods (wsCNRs are exploited for their light-driven photochemical activities under outdoor sunlight. wsCNRs were synthesized by a simple pyrolysis method from castor seed oil, without using any metal catalyst or template. wsCNRs exhibited the light-induced photochemical degradation of methylene blue used as a model pollutant by the generation of singlet oxygen species. Herein, we described a possible degradation mechanism of methylene blue under the irradiation of visible photons via the singlet oxygen-superoxide anion pathway.

  18. Bacterial growth in humic waters exposed to UV-radiation and simulated sunlight

    DEFF Research Database (Denmark)

    Corin, N.; Backlund, P.; Wiklund, T.

    1998-01-01

    Sterile filtered (0.45 mu m) humic lake water was exposed to simulated sunlight (300-800 nm) or W-radiation (254 run)for various periods of times and the dissolved organic carbon content, absorbance at 254 and 460 nm and PH were recorded. The irradiated water was inoculated with a natural bacterial...... in an increased availability of the dissolved organic material as bacterial substrate. No inhibitory effect on the bacterial growth, due to the presence of toxic organic reaction products, was observed. (C) 1998 Published by Elsevier Science Ltd....

  19. Sunlight simulators-the key to understanding the physiological effects of the sun

    CSIR Research Space (South Africa)

    Singh, A

    2006-07-01

    Full Text Available simulator Slide 4 © CSIR 2006 www.csir.co.za ۞ Benefits of natural sunlight ۞ Restrictions of lifestyles ۞ Common misconceptions ۞ Experimental setups Slide 5 © CSIR 2006 www.csir.co.za Cancer Males... Females Cases Deaths Cases Deaths Oral cavity 175,916 80,736 98,373 46,723 Esophagus 315,394 261,162 146,723 124,730 Stomach 603,419 446,052 330,518 254,297 Colon/rectum 550,465 278,446 472,687 250,532 Liver 442,119 416,882 184...

  20. Sunlight effects on the 3D polar current system determined from low Earth orbit measurements

    DEFF Research Database (Denmark)

    Laundal, Karl M.; Finlay, Chris; Olsen, Nils

    2016-01-01

    analyzed together. In this paper, we present estimates of the average global Birkeland currents and horizontal ionospheric currents from the same set of magnetic field measurements. The magnetic field measurements, from the low Earth orbiting Swarm and CHAMP satellites, are used to co-estimate poloidal...... show that the Birkeland currents vary with the conductivity, which depends most strongly on solar EUV emissions on the dayside and on particle precipitation at pre-midnight magnetic local times. In sunlight, the horizontal equivalent current flows in two cells, resembling an opposite ionospheric...

  1. Effect of sunlight irradiation on photocatalytic pyrene degradation in contaminated soils by micro-nano size TiO2.

    Science.gov (United States)

    Chang Chien, S W; Chang, C H; Chen, S H; Wang, M C; Madhava Rao, M; Satya Veni, S

    2011-09-01

    The enhanced catalytic pyrene degradation in quartz sand and alluvial and red soils by micro-nano size TiO(2) in the presence and absence of sunlight was investigated. The results showed that the synergistic effect of sunlight irradiation and TiO(2) was more efficient on pyrene degradation in quartz sand and red and alluvial soils than the corresponding reaction system without sunlight irradiation. In the presence of sunlight irradiation, the photooxidation (without TiO(2)) of pyrene was very pronounced in alluvial and red soils and especially in quartz sand. However, in the absence of sunlight irradiation, the catalytic pyrene degradation by TiO(2) and the photooxidation (without TiO(2)) of pyrene were almost nil. This implicates that ultra-violet (UV) wavelength range of sunlight plays an important role in TiO(2)-enhanced photocatalytic pyrene degradation and in photooxidation (without TiO(2)) of pyrene. The percentages of photocatalytic pyrene degradation by TiO(2) in quartz sand, alluvial and red soils under sunlight irradiation were 78.3, 23.4, and 31.8%, respectively, at 5h reaction period with a 5% (w/w) dose of the amended catalyst. The sequence of TiO(2)-enhanced catalytic pyrene degradation in quartz sand and alluvial and red soils was quartz sand>red soil>alluvial soil, due to different texture and total organic carbon (TOC) contents of the quartz sand and other two soils. The differential Fourier transform infrared (FT-IR) spectra of degraded pyrene in alluvial soil corroborate that TiO(2)-enhanced photocatalytic degradation rate of degraded pyrene was much greater than photooxidation (without TiO(2)) rate of degraded pyrene. Based on the data obtained, the importance for the application of TiO(2)-enhanced photocatalytic pyrene degradation and associated organic contaminants in contaminated soils was elucidated.

  2. Mutation spectrum in sunlight-exposed mouse skin epidermis: small but appreciable contribution of oxidative stress-mediated mutagenesis

    Energy Technology Data Exchange (ETDEWEB)

    Ikehata, Hironobu [Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai 980-8575 (Japan)]. E-mail: ikehata@mail.tains.tohoku.ac.jp; Nakamura, Shingo [Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai 980-8575 (Japan); Department of Radiobiology, Institute for Environmental Sciences, Aomori 039-3212 (Japan); Asamura, Takaaki [Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai 980-8575 (Japan); Ono, Tetsuya [Department of Cell Biology, Graduate School of Medicine, Tohoku University, Sendai 980-8575 (Japan)

    2004-11-22

    We studied the mutations induced in skin by sunlight using transgenic Muta{sup TM} mice. Noon sunlight during summer at Sendai, Japan induced mutations efficiently in both epidermis and dermis. The mutant frequency (MF) in epidermis reached nearly 0.5% during the first 40 min irradiation but became saturated at this level with the appearance of skin inflammation after further irradiation. At the equivalent inflammatory dose, sunlight was twice as genotoxic as 313 nm-peak UVB. The 81 mutations detected in 80 lacZ transgene mutants isolated from the sunlight-exposed epidermis were dominated by C {yields} T transitions (89%), occurring exclusively at dipyrimidine sites, and also included a CC {yields} TT tandem substitution. Thus, the sunlight-induced mutation spectrum is highly UV-specific, quite similar to that induced by UVB but significantly different from that induced by UVA. Although oxidative damage-related C {yields} A transversions were detected only in five mutants (6%), their frequency was elevated to at least 15 times the background level, suggesting that the contribution of UVA-mediated oxidative stress is comparatively small but considerable. An analysis of bases adjacent to the mutated cytosines revealed that the sunlight-induced mutations prefer 5'-TC-3' dipyrimidine sites to 5'-CC-3' and 5'-CT-3'. The distribution of the frequent C {yields} T transition sites in the transgene was well associated with the CpG motif, which is known to be completely methylated in the gene, and quite similar to that induced by UVB rather than that by UVA. Thus, the UVB component contributes to the sunlight-induced mutations in the mammalian skin much more than the UVA component, whose influence through reactive oxygen species (ROS)-mediated mutagenesis is still appreciable.

  3. Large Crater Clustering tool

    Science.gov (United States)

    Laura, Jason; Skinner, James A.; Hunter, Marc A.

    2017-08-01

    In this paper we present the Large Crater Clustering (LCC) tool set, an ArcGIS plugin that supports the quantitative approximation of a primary impact location from user-identified locations of possible secondary impact craters or the long-axes of clustered secondary craters. The identification of primary impact craters directly supports planetary geologic mapping and topical science studies where the chronostratigraphic age of some geologic units may be known, but more distant features have questionable geologic ages. Previous works (e.g., McEwen et al., 2005; Dundas and McEwen, 2007) have shown that the source of secondary impact craters can be estimated from secondary impact craters. This work adapts those methods into a statistically robust tool set. We describe the four individual tools within the LCC tool set to support: (1) processing individually digitized point observations (craters), (2) estimating the directional distribution of a clustered set of craters, back projecting the potential flight paths (crater clusters or linearly approximated catenae or lineaments), (3) intersecting projected paths, and (4) intersecting back-projected trajectories to approximate the local of potential source primary craters. We present two case studies using secondary impact features mapped in two regions of Mars. We demonstrate that the tool is able to quantitatively identify primary impacts and supports the improved qualitative interpretation of potential secondary crater flight trajectories.

  4. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    .g. sustainability or quality of life. The purpose of this paper is to explore how and to what extent public sector interventions that aim at forcing cluster development in industries can support sustainable development as defined in the Brundtland tradition and more recently elaborated in such concepts as eco......, Portugal and New Zealand have adopted the concept. Public sector interventions that aim to support cluster development in industries most often focus upon economic policy goals such as enhanced employment and improved productivity, but rarely emphasise broader societal policy goals relating to e...... to the automotive sector in Wales. Specifically, the paper evaluates the "Accelerates" programme initiated by the Welsh Development Agency and elaborates on how and to what extent the Accelerate programme supports the development of a sustainable automotive industry cluster. The Accelerate programme was set up...

  5. Sunlight exposure and sun sensitivity associated with disability progression in multiple sclerosis.

    Science.gov (United States)

    D'hooghe, M B; Haentjens, P; Nagels, G; Garmyn, M; De Keyser, J

    2012-04-01

    Sunlight and vitamin D have been inversely associated with the risk of multiple sclerosis (MS). We investigated sunlight exposure and sun sensitivity in relation to disability progression in MS. We conducted a survey among persons with MS, registered by the Flemish MS society, Belgium, and stratified data according to relapsing-onset and progressive-onset MS. We used Kaplan-Meier survival and Cox proportional hazard regression analyses with time to Expanded Disability Status Scale (EDSS) 6 as outcome measure. Hazard ratios for the time from onset and from birth were calculated for the potentially predictive variables, adjusting for age at onset, gender and immunomodulatory treatment. 704 (51.3%) of the 1372 respondents had reached EDSS 6. In relapsing-onset MS, respondents reporting equal or higher levels of sun exposure than persons of the same age in the last 10 years had a decreased risk of reaching EDSS 6. In progressive-onset MS, increased sun sensitivity was associated with an increased hazard of reaching EDSS 6. The association of higher sun exposure with a better outcome in relapsing-onset MS may be explained by either a protective effect or reverse causality. Mechanisms underlying sun sensitivity might influence progression in progressive-onset MS.

  6. Factors influencing adherence with therapeutic sunlight exposure in older people in intermediate care facilities.

    Science.gov (United States)

    Durvasula, Seeta; Sambrook, Philip N; Cameron, Ian D

    2012-01-01

    The purpose of this study was to investigate the factors influencing low adherence with therapeutic sunlight exposure in a randomized controlled trial conducted with older people living in intermediate care facilities. The study involved participants in the FREEDOM (Falls Risk Epidemiology: Effect of vitamin D on skeletal Outcomes and other Measures) study, a randomized controlled trial of therapeutic sun exposure to reduce falls in older people in intermediate care facilities. Semi-structured interviews were conducted with thirty participants in the FREEDOM trial, and with ten sunlight officers who were employed to facilitate the sun exposure. Two focus groups involving 10 participants in the FREEDOM trial were also held at the end of the intervention period. Common themes were derived from the interview and focus group transcripts. The study showed that the perceived health benefits did not influence adherence with the sun exposure. Factors such as socializing with others and being outdoors were more important in encouraging attendance. The main barriers to adherence included the perceived inflexibility and regimentation of daily attendance, clash with other activities, unsuitable timing and heat discomfort. This study showed that providing greater flexibility and autonomy to older people in how and when they receive sun exposure is likely to improve adherence. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  7. Low exposure to sunlight is a risk factor for Crohn's disease.

    Science.gov (United States)

    Nerich, V; Jantchou, P; Boutron-Ruault, M-C; Monnet, E; Weill, A; Vanbockstael, V; Auleley, G-R; Balaire, C; Dubost, P; Rican, S; Allemand, H; Carbonnel, F

    2011-04-01

    Low sunshine exposure might contribute to the pathogenesis of inflammatory bowel disease (IBD). To assess the geographic distribution of IBD incidence in relation to sunshine exposure in France to test the hypothesis that higher sun exposure is associated with lower IBD risk. Using the national health insurance database, incidence rates of Crohn's disease (CD) and ulcerative colitis (UC) were estimated for each of the 94 French administrative areas ('départements'), between 2000 and 2002. The surface UV radiation intensity was obtained by combining modelling and satellite data from Meteosat, the European meteorological satellite. Relationships between incidence rates and sun exposure were tested for significance by using a Poisson regression. We mapped smoothed relative risks (sRR) for CD and UC, using a Bayesian approach and adjusting for sun exposure, to search for geographical variations. Areas with a smoothed RR of CD incidence significantly above 1 corresponded to areas with low sunshine exposure, whereas those with high or medium sunlight exposure had smoothed RRs either lower than 1 or not significantly different from 1. There was no association between sun exposure and UC incidence. This geographic study suggests that low sunlight exposure is associated with an increased incidence of Crohn's disease. Further studies are needed to determine if this association is causal. © 2011 Blackwell Publishing Ltd.

  8. Years of sunlight exposure and cataract: a case-control study in a Mediterranean population

    Science.gov (United States)

    Pastor-Valero, María; Fletcher, Astrid E; de Stavola, Bianca L; Chaqués-Alepúz, Vicente

    2007-01-01

    Background We aimed to investigate the relation between sunlight exposure and risk of cataract. Methods We carried out a frequency-matched case-control study of 343 cases and 334 controls attending an ophthalmology outpatient clinic at a primary health-care center in a small town near Valencia, Spain. All cases were diagnosed as having a cataract in at least one eye based on the Lens Opacification Classification system (LOCS II). Controls had no opacities in either eye. All cases and controls were interviewed for information on outdoor exposure, "usual" diet, history of severe episodes of diarrhea illness, life-style factors and medical and socio-demographic variables. Blood antioxidant vitamin levels were also analyzed. We used logistic regression models to estimate sex and age-adjusted odds ratios (ORs) by quintiles of years of occupational outdoor exposure, adjusting for potential confounders such as smoking, alcohol consumption, serum antioxidants and education. Results No association was found between years of outdoor exposure and risk of cataract. However, exploratory analyses suggested a positive association between years of outdoor exposure at younger ages and risk of nuclear cataract later in life. Conclusion Our study does not support an association with cataract and sunlight exposure over adult life. PMID:18039367

  9. Sunlight triggers cutaneous lupus through a CSF-1-dependent mechanism in MRL-Fas(lpr) mice.

    Science.gov (United States)

    Menke, Julia; Hsu, Mei-Yu; Byrne, Katelyn T; Lucas, Julie A; Rabacal, Whitney A; Croker, Byron P; Zong, Xiao-Hua; Stanley, E Richard; Kelley, Vicki R

    2008-11-15

    Sunlight (UVB) triggers cutaneous lupus erythematosus (CLE) and systemic lupus through an unknown mechanism. We tested the hypothesis that UVB triggers CLE through a CSF-1-dependent, macrophage (Mø)-mediated mechanism in MRL-Fas(lpr) mice. By constructing mutant MRL-Fas(lpr) strains expressing varying levels of CSF-1 (high, intermediate, none), and use of an ex vivo gene transfer to deliver CSF-1 intradermally, we determined that CSF-1 induces CLE in lupus-susceptible MRL-Fas(lpr) mice, but not in lupus-resistant BALB/c mice. UVB incites an increase in Møs, apoptosis in the skin, and CLE in MRL-Fas(lpr), but not in CSF-1-deficient MRL-Fas(lpr) mice. Furthermore, UVB did not induce CLE in BALB/c mice. Probing further, UVB stimulates CSF-1 expression by keratinocytes leading to recruitment and activation of Møs that, in turn, release mediators, which induce apoptosis in keratinocytes. Thus, sunlight triggers a CSF-1-dependent, Mø-mediated destructive inflammation in the skin leading to CLE in lupus-susceptible MRL-Fas(lpr) but not lupus-resistant BALB/c mice. Taken together, CSF-1 is envisioned as the match and lupus susceptibility as the tinder leading to CLE.

  10. Dose-Response Effect of Sunlight on Vitamin D2 Production in Agaricus bisporus Mushrooms

    DEFF Research Database (Denmark)

    Urbain, Paul; Jakobsen, Jette

    2015-01-01

    The dose response effect of UV-B irradiation from sunlight on vitamin D2 content of sliced Agaricus bisporus (white button mushroom) during the process of sun-drying was investigated.Real-time UV-B and UV-A data were obtained using a high-performance spectroradiometer. During the first hour...... of sunlight exposure, the vitamin D2 content of the mushrooms increased in a linear manner, with concentrations increasing from 0.1 μg/g up to 3.9 ± 0.8 μg/g dry weight (DW). At the subsequent two measurements one and 3 h later, respectively, a plateau was reached. Two hours of additional exposure triggered...... a significant decline in vitamin D2 content. After just 15 min of sun exposure and an UV-B dose of 0.13 J/cm(2), the vitamin D2 content increased significantly to 2.2 ± 0.5 μg/g DW (P vitamin D2 per 100 g of fresh mushrooms and comparable to levels found...

  11. Surface exposure to sunlight stimulates CO2 release from permafrost soil carbon in the Arctic.

    Science.gov (United States)

    Cory, Rose M; Crump, Byron C; Dobkowski, Jason A; Kling, George W

    2013-02-26

    Recent climate change has increased arctic soil temperatures and thawed large areas of permafrost, allowing for microbial respiration of previously frozen C. Furthermore, soil destabilization from melting ice has caused an increase in thermokarst failures that expose buried C and release dissolved organic C (DOC) to surface waters. Once exposed, the fate of this C is unknown but will depend on its reactivity to sunlight and microbial attack, and the light available at the surface. In this study we manipulated water released from areas of thermokarst activity to show that newly exposed DOC is >40% more susceptible to microbial conversion to CO(2) when exposed to UV light than when kept dark. When integrated over the water column of receiving rivers, this susceptibility translates to the light-stimulated bacterial activity being on average from 11% to 40% of the total areal activity in turbid versus DOC-colored rivers, respectively. The range of DOC lability to microbes seems to depend on prior light exposure, implying that sunlight may act as an amplification factor in the conversion of frozen C stores to C gases in the atmosphere.

  12. Terrestrial photovoltaic power systems with sunlight concentration. Annual progress report, January 1, 1975--December 31, 1975

    Energy Technology Data Exchange (ETDEWEB)

    Backus, C.E.

    1976-01-31

    This annual report is for the second year of a program to investigate the characteristics of the components and the total system using sunlight concentrated onto solar cells. The second year was primarily to experimentally investigate the conclusions of the first year of analytical studies. Cells have been fabricated that are designed for different intensities. Typically the efficiency of a cell will increase from its 11 percent at AM1 peak to efficiency at the designed concentration level and return to its initial efficiency at about 3 times its designed concentration level. The developed cells have been tested under high intensity simulators and in concentrated sunlight and have shown to have the predicted response. The experimental testing of passive cooling limitations for cooling cells with just finned arrangements in the back of the cell has been completed in the controlled environment of a wind tunnel. These experiments have confirmed the heat transfer coefficients that had been used in the analytical studies. Testing was done to collect heat transfer coefficients for actual wind conditions and these data show good agreement with the controlled wind tunnel data. Four photovoltaic/concentrator system experiments have been started with CR of about 3, 10, 25, and 100. System analysis has indicated that photovoltaic concentration systems may be attractive in low solar irradiation areas such as Cleveland.

  13. A full-sunlight-driven photocatalyst with super long-persistent energy storage ability.

    Science.gov (United States)

    Li, Jie; Liu, Yuan; Zhu, Zhijian; Zhang, Guozhu; Zou, Tao; Zou, Zhijun; Zhang, Shunping; Zeng, Dawen; Xie, Changsheng

    2013-01-01

    A major drawback of traditional photocatalysts like TiO2 is that they can only work under illumination, and the light has to be UV. As a solution for this limitation, visible-light-driven energy storage photocatalysts have been developed in recent years. However, energy storage photocatalysts that are full-sunlight-driven (UV-visible-NIR) and possess long-lasting energy storage ability are lacking. Here we report, a Pt-loaded and hydrogen-treated WO3 that exhibits a strong absorption at full-sunlight spectrum (300-1,000 nm), and with a super-long energy storage time of more than 300 h to have formaldehyde degraded in dark. In this new material system, the hydrogen treated WO3 functions as the light harvesting material and energy storage material simultaneously, while Pt mainly acts as the cocatalyst to have the energy storage effect displayed. The extraordinary full-spectrum absorption effect and long persistent energy storage ability make the material a potential solar-energy storage and an effective photocatalyst in practice.

  14. Years of sunlight exposure and cataract: a case-control study in a Mediterranean population

    Directory of Open Access Journals (Sweden)

    de Stavola Bianca L

    2007-11-01

    Full Text Available Abstract Background We aimed to investigate the relation between sunlight exposure and risk of cataract. Methods We carried out a frequency-matched case-control study of 343 cases and 334 controls attending an ophthalmology outpatient clinic at a primary health-care center in a small town near Valencia, Spain. All cases were diagnosed as having a cataract in at least one eye based on the Lens Opacification Classification system (LOCS II. Controls had no opacities in either eye. All cases and controls were interviewed for information on outdoor exposure, "usual" diet, history of severe episodes of diarrhea illness, life-style factors and medical and socio-demographic variables. Blood antioxidant vitamin levels were also analyzed. We used logistic regression models to estimate sex and age-adjusted odds ratios (ORs by quintiles of years of occupational outdoor exposure, adjusting for potential confounders such as smoking, alcohol consumption, serum antioxidants and education. Results No association was found between years of outdoor exposure and risk of cataract. However, exploratory analyses suggested a positive association between years of outdoor exposure at younger ages and risk of nuclear cataract later in life. Conclusion Our study does not support an association with cataract and sunlight exposure over adult life.

  15. Dose-Response Effect of Sunlight on Vitamin D2 Production in Agaricus bisporus Mushrooms.

    Science.gov (United States)

    Urbain, Paul; Jakobsen, Jette

    2015-09-23

    The dose response effect of UV-B irradiation from sunlight on vitamin D2 content of sliced Agaricus bisporus (white button mushroom) during the process of sun-drying was investigated.Real-time UV-B and UV-A data were obtained using a high-performance spectroradiometer. During the first hour of sunlight exposure, the vitamin D2 content of the mushrooms increased in a linear manner, with concentrations increasing from 0.1 μg/g up to 3.9 ± 0.8 μg/g dry weight (DW). At the subsequent two measurements one and 3 h later, respectively, a plateau was reached. Two hours of additional exposure triggered a significant decline in vitamin D2 content. After just 15 min of sun exposure and an UV-B dose of 0.13 J/cm(2), the vitamin D2 content increased significantly to 2.2 ± 0.5 μg/g DW (P < 0.0001), which is equivalent to 17.6 μg (704 IU) vitamin D2 per 100 g of fresh mushrooms and comparable to levels found in fatty fish like the Atlantic salmon.

  16. Chloroplast avoidance movement is not functional in plants grown under strong sunlight.

    Science.gov (United States)

    Higa, Takeshi; Wada, Masamitsu

    2016-04-01

    Chloroplast movement in nine climbing plant species was investigated. It is thought that chloroplasts generally escape from strong light to avoid photodamage but accumulate towards weak light to perform photosynthesis effectively. Unexpectedly, however, the leaves of climbing plants grown under strong sunlight showed very low or no chloroplast photorelocation responses to either weak or strong blue light when detected by red light transmittance through leaves. Direct observations of Cayratia japonica leaves, for example, revealed that the average number of chloroplasts in upper periclinal walls of palisade tissue cells was only 1.2 after weak blue-light irradiation and almost all of the chloroplasts remained at the anticlinal wall, the state of chloroplast avoidance response. The leaves grown under strong light have thin and columnar palisade tissue cells comparing with the leaves grown under low light. Depending on our analyses and our schematic model, the thinner cells in a unit leaf area have a wider total plasma membrane area, such that more chloroplasts can exist on the plasma membrane in the thinner cells than in the thicker cells in a unit leaf-area basis. The same strategy might be used in other plant leaves grown under direct sunlight.

  17. Natural organic matter and sunlight accelerate the degradation of 17ss-estradiol in water

    Energy Technology Data Exchange (ETDEWEB)

    Leech, Dina M. [Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3431 Arendell Street, Morehead City, NC 28557 (United States)], E-mail: dmleech@email.unc.edu; Snyder, Matthew T.; Wetzel, Robert G. [Department of Environmental Sciences and Engineering, School of Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States)

    2009-03-01

    Nanomolar concentrations of steroid hormones such as 17{beta}-estradiol can influence the reproductive development and sex ratios of invertebrate and vertebrate populations. Thus their release into surface and ground waters from wastewater facilities and agricultural applications of animal waste is of environmental concern. Many of these compounds are chromophoric and susceptible to photolytic degradation. High intensity UV-C radiation has been demonstrated to degrade some of these compounds in engineered systems. However, the degradation efficacy of natural solar radiation in shallow fresh waters is less understood. Here photolytic experiments with 17{beta}-estradiol demonstrated modest photodegradation ({approx} 26%) when exposed to simulated sunlight between 290 and 720 nm. Photodegradation significantly increased ({approx} 40-50%) in the presence of 2.0-15.0 mg/l of dissolved organic carbon (DOC) derived from humic acids of the Suwannee River, GA. However, rates of photodegradation reached a threshold at approximately 5.0 mg/l DOC. Observed suppression of photolysis in the presence of a radical inhibitor (i.e. 2-propanol) indicated that a significant proportion of the degradation was due to radicals formed from the photolysis of DOC. Although photodegradation was greatest in full sunlight containing UV-B (290-320 nm), degradation was also detected with UV-A (320-400 nm) and visible light (400-720 nm) alone.

  18. Improving the sunlight-to-biomass conversion efficiency in microalgal biofactories.

    Science.gov (United States)

    Wobbe, Lutz; Remacle, Claire

    2015-05-10

    Microalgae represent promising organisms for the sustainable production of commodities, chemicals or fuels. Future use of such systems, however, requires increased productivity of microalgal mass cultures in order to reach an economic viability for microalgae-based production schemes. The efficiency of sunlight-to-biomass conversion that can be observed in bulk cultures is generally far lower (35-80%) than the theoretical maximum, because energy losses occur at multiple steps during the light-driven conversion of carbon dioxide to organic carbon. The light-harvesting system is a major source of energy losses and thus a prime target for strain engineering. Truncation of the light-harvesting antenna in the algal model organism Chlamydomonas reinhardtii was shown to be an effective way of increasing culture productivity at least under saturating light conditions. Furthermore engineering of the Calvin-Benson cycle or the creation of photorespiratory bypasses in A. thaliana proved to be successful in terms of achieving higher biomass productivities. An efficient generation of novel microalgal strains with improved sunlight conversion efficiencies by targeted engineering in the future will require an expanded molecular toolkit. In the meantime random mutagenesis coupled to high-throughput screening for desired phenotypes can be used to provide engineered microalgae. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew J.

    2006-02-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing 10^4 - 10^7 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker-Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  20. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Benacquista Matthew

    2002-01-01

    Full Text Available The galactic population of globular clusters are old, dense star systems, with a typical cluster containing $10^4 - 10^6$ stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss the theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution which lead to relativistic binaries, and current and possible future observational evidence for this population. Globular cluster evolution will focus on the properties that boost the production of hard binary systems and on the tidal interactions of the galaxy with the cluster, which tend to alter the structure of the globular cluster with time. The interaction of the components of hard binary systems alters the evolution of both bodies and can lead to exotic objects. Direct $N$-body integrations and Fokker--Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  1. How long can culturable bacteria and total DNA persist in environmental waters? The role of sunlight and solid particles.

    Science.gov (United States)

    Gutiérrez-Cacciabue, Dolores; Cid, Alicia G; Rajal, Verónica B

    2016-01-01

    In this work, sunlight inactivation of two indicator bacteria in freshwater, with and without solid particles, was studied and the persistence of culturable cells and total DNA was compared. Environmental water was used to prepare two matrices, with and without solid particles, which were spiked with Escherichia coli and Enterococcus faecalis. These matrices were used to prepare microcosm bags that were placed in two containers: one exposed to sunlight and the other in the dark. During one month, samples were removed from each container and detection was done by membrane filter technique and real-time PCR. Kinetic parameters were calculated to assess sunlight effect. Indicator bacteria without solid particles exposed to sunlight suffered an immediate decay (solid particles varied depending on the situation analyzed (T99 from 3 up to 60days), being always culturable E. coli more persistent than E. faecalis. On the other side, E. faecalis DNA persisted much longer than culturable cells (T99>40h in the dark with particles). In this case active cells were more prone to sunlight than total DNA and the protective effect of solid particles was also observed. Results highlight that the effects caused by the parameters which describe the behavior of culturable microorganisms and total DNA in water are different and must be included in simulation models but without forgetting that these parameters will also depend on bacterial properties, sensitizers, composition, type, and uses of the aquatic environment under assessment.

  2. Cluster forcing

    DEFF Research Database (Denmark)

    Christensen, Thomas Budde

    The cluster theory attributed to Michael Porter has significantly influenced industrial policies in countries across Europe and North America since the beginning of the 1990s. Institutions such as the EU, OECD and the World Bank and governments in countries such as the UK, France, The Netherlands...

  3. Detection of diurnal variation of tomato transcriptome through the molecular timetable method in a sunlight-type plant factory

    Directory of Open Access Journals (Sweden)

    Takanobu eHigashi

    2016-02-01

    Full Text Available The timing of measurement during plant growth is important because many genes are expressed periodically and orchestrate physiological events. Their periodicity is generated by environmental fluctuations as external factors and the circadian clock as the internal factor. The circadian clock orchestrates physiological events such as photosynthesis or flowering and it enables enhanced growth and herbivory resistance. These characteristics have possible applications for agriculture. In this study, we demonstrated the diurnal variation of the transcriptome in tomato (Solanum lycopersicum leaves through molecular timetable method in a sunlight-type plant factory. Molecular timetable method have been developed to detect periodic genes and estimate individual internal body time from these expression profiles in mammals. We sampled tomato leaves every 2 h for 2 d and acquired time-course transcriptome data by RNA-Seq. Many genes were expressed periodically and these expressions were stable across the 1st and 2nd days of measurement. We selected 143 time-indicating genes whose expression indicated periodically, and estimated internal time in the plant from these expression profiles. The estimated internal time was generally the same as the external environment time; however, there was a difference of more than one hour between the two for some sampling points. Furthermore, the stress-responsive genes also showed weakly periodic expression, implying that they were usually expressed periodically, regulated by light–dark cycles as an external factor or the circadian clock as the internal factor, and could be particularly expressed when the plant experiences some specific stress under agricultural situations. This study suggests that circadian clock mediate the optimization for fluctuating environments in the field and it has possibilities to enhance resistibility to stress and floral induction by controlling circadian clock through light supplement and

  4. Detection of Diurnal Variation of Tomato Transcriptome through the Molecular Timetable Method in a Sunlight-Type Plant Factory.

    Science.gov (United States)

    Higashi, Takanobu; Tanigaki, Yusuke; Takayama, Kotaro; Nagano, Atsushi J; Honjo, Mie N; Fukuda, Hirokazu

    2016-01-01

    The timing of measurement during plant growth is important because many genes are expressed periodically and orchestrate physiological events. Their periodicity is generated by environmental fluctuations as external factors and the circadian clock as the internal factor. The circadian clock orchestrates physiological events such as photosynthesis or flowering and it enables enhanced growth and herbivory resistance. These characteristics have possible applications for agriculture. In this study, we demonstrated the diurnal variation of the transcriptome in tomato (Solanum lycopersicum) leaves through molecular timetable method in a sunlight-type plant factory. Molecular timetable methods have been developed to detect periodic genes and estimate individual internal body time from these expression profiles in mammals. We sampled tomato leaves every 2 h for 2 days and acquired time-course transcriptome data by RNA-Seq. Many genes were expressed periodically and these expressions were stable across the 1st and 2nd days of measurement. We selected 143 time-indicating genes whose expression indicated periodically, and estimated internal time in the plant from these expression profiles. The estimated internal time was generally the same as the external environment time; however, there was a difference of more than 1 h between the two for some sampling points. Furthermore, the stress-responsive genes also showed weakly periodic expression, implying that they were usually expressed periodically, regulated by light-dark cycles as an external factor or the circadian clock as the internal factor, and could be particularly expressed when the plant experiences some specific stress under agricultural situations. This study suggests that circadian clock mediate the optimization for fluctuating environments in the field and it has possibilities to enhance resistibility to stress and floral induction by controlling circadian clock through light supplement and temperature control.

  5. Quantification of ultraviolet radiation-induced DNA damage in the urine of Swedish adults and children following exposure to sunlight.

    Science.gov (United States)

    Liljendahl, Tove Sandberg; Kotova, Natalia; Segerbäck, Dan

    2012-11-01

    DNA damage following exposure to ultraviolet radiation (UVR) is important in skin cancer development. The predominant photoproduct, cyclobutane thymine dimer (T=T), is repaired and excreted in the urine, where it provides a biomarker of exposure. To quantify urinary T=T levels after recreational sunlight exposure in adults and children. Average UVR doses were measured with personal dosimeters. Urinary T=T was analysed with (32)P-postlabelling. Background levels of T=T increased significantly following exposure to sunlight. Amounts of T=T in urine of children and adults were not significantly different after adjusting for area of skin exposed and physiological differences. UVR dose and amounts of T=T correlated for both adults and children. Recreational exposure to sunlight in Sweden induces levels of DNA damage, clearly detectable in urine.

  6. Photocatalytic Synthesis of Phenol by Direct Hydroxylation of Benzene by a Modified Nanoporous Silica (LUS-1) under Sunlight

    Institute of Scientific and Technical Information of China (English)

    Ghasem SHIRAVAND; Alireza BADIEI; Ghodsi Mohammadi ZIARANI; Morteza JAFARABADI; Majid HAMZEHLOO

    2012-01-01

    Fe-g-C3N4-LUS-1was prepared by the thermal decomposition of dicyandiamide inside the pores of LUS-1under an inert atmosphere.It was used as a photocatalyst for the hydroxylation of benzene to phenol in sunlight.The catalysts were characterized by Fourier transform infrared spectroscopy,N2 adsorption-desorption,X-ray diffraction,and scanning electron microscopy.In Fe-g-C3N4-LUS-1,a single layer of graphitic carbon nitride (g-C3N4) was formed on the surface of LUS-1.The photocatalytic activity of the iron containing g-C3N4based catalysts was investigated,and the catalytic activity was remarkably enhanced when the reaction condition was changed from dark to sunlight.The best result was obtained with 20%Fe-g-C3N4-LUS-1 in sunlight.

  7. Quotients of cluster categories

    OpenAIRE

    Jorgensen, Peter

    2007-01-01

    Higher cluster categories were recently introduced as a generalization of cluster categories. This paper shows that in Dynkin types A and D, half of all higher cluster categories are actually just quotients of cluster categories. The other half can be obtained as quotients of 2-cluster categories, the "lowest" type of higher cluster categories. Hence, in Dynkin types A and D, all higher cluster phenomena are implicit in cluster categories and 2-cluster categories. In contrast, the same is not...

  8. Cost-effectiveness of intensive multifactorial treatment compared with routine care for individuals with screen-detected Type 2 diabetes : analysis of the ADDITION-UK cluster-randomized controlled trial

    NARCIS (Netherlands)

    Tao, L.; Wilson, E. C. F.; Wareham, N. J.; Sandbaek, A.; Rutten, G. E. H. M.|info:eu-repo/dai/nl/074622781; Lauritzen, T.; Khunti, K.; Davies, M. J.; Borch-Johnsen, K.; Griffin, S. J.; Simmons, R. K.

    2015-01-01

    Aims To examine the short- and long-term cost-effectiveness of intensive multifactorial treatment compared with routine care among people with screen-detected Type 2 diabetes. Methods Cost-utility analysis in ADDITION-UK, a cluster-randomized controlled trial of early intensive treatment in people w

  9. Cost-effectiveness of intensive multifactorial treatment compared with routine care for individuals with screen-detected Type 2 diabetes : analysis of the ADDITION-UK cluster-randomized controlled trial

    NARCIS (Netherlands)

    Tao, L.; Wilson, E. C. F.; Wareham, N. J.; Sandbaek, A.; Rutten, G. E. H. M.; Lauritzen, T.; Khunti, K.; Davies, M. J.; Borch-Johnsen, K.; Griffin, S. J.; Simmons, R. K.

    2015-01-01

    Aims To examine the short- and long-term cost-effectiveness of intensive multifactorial treatment compared with routine care among people with screen-detected Type 2 diabetes. Methods Cost-utility analysis in ADDITION-UK, a cluster-randomized controlled trial of early intensive treatment in people w

  10. Preparation of K-doped TiO2 nanostructures by wet corrosion and their sunlight-driven photocatalytic performance

    Science.gov (United States)

    Shin, Eunhye; Jin, Saera; Kim, Jiyoon; Chang, Sung-Jin; Jun, Byung-Hyuk; Park, Kwang-Won; Hong, Jongin

    2016-08-01

    K-doped TiO2 nanowire networks were prepared by the corrosion reaction of Ti nanoparticles in an alkaline (potassium hydroxide: KOH) solution. The prepared nanostructures were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, X-ray diffraction (XRD) and photoluminescence (PL) spectra. Their sunlight-driven photocatalytic activity was also investigated with differently charged dye molecules, such as methylene blue, rhodamine B and methyl orange. The adsorption of the dye molecules on the photocatalyst surface would play a critical role in their selective photodegradation under sunlight illumination.

  11. Regional Innovation Clusters

    Data.gov (United States)

    Small Business Administration — The Regional Innovation Clusters serve a diverse group of sectors and geographies. Three of the initial pilot clusters, termed Advanced Defense Technology clusters,...

  12. Clustering Millions of Faces by Identity.

    Science.gov (United States)

    Otto, Charles; Wang, Dayong; Jain, Anil

    2017-03-07

    Given a large collection of unlabeled face images, we address the problem of clustering faces into an unknown number of identities. This problem is of interest in social media, law enforcement, and other applications, where the number of faces can be of the order of hundreds of million, while the number of identities (clusters) can range from a few thousand to millions. To address the challenges of run-time complexity and cluster quality, we present an approximate Rank-Order clustering algorithm that performs better than popular clustering algorithms (k-Means and Spectral). Our experiments include clustering up to 123 million face images into over 10 million clusters. Clustering results are analyzed in terms of external (known face labels) and internal (unknown face labels) quality measures, and run-time. Our algorithm achieves an F-measure of 0:87 on the LFW benchmark (13K faces of 5; 749 individuals), which drops to 0:27 on the largest dataset considered (13K faces in LFW + 123M distractor images). Additionally, we show that frames in the YouTube benchmark can be clustered with an F-measure of 0:71. An internal per-cluster quality measure is developed to rank individual clusters for manual exploration of high quality clusters that are compact and isolated.

  13. Iron (III) aquacomplexes as catalysts for pesticides mineralisation by sunlight irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Catastini, C.; Mailhot, G.; Malato, S.; Sarakha, M.

    2002-07-01

    The experimental results of the photo catalytic degradation of the pesticide asulam (4-amino-benzosulfonyl-methylcarbamate) in aqueous solutions using iron (III) aquacomplexes as photo inducer and sunlight as irradiation source are reported. The experiments were conducted in a compound parabolic collector reactor (CPC) of Plataforma solar de Almeria. In the early stages of the irradiation, the degradation is clearly due to the photo redox process involving the most photoactive species of iron (III) (Fe(OH)''2+). The degradation was also shown to proceed when iron (II) was used as a photo inducer in aerated aqueous solutions. In both cases, the complete degradation of the substrate to CO{sub 2} in aerated aqueous solutions needed exposition to solar light of about 13-14 hours. A catalytic process involving iron (III), iron (II), oxygen and light is proposed. (Author) 24 refs.

  14. Design and fabrication of light-guiding plate for a photobioreactor that utilizes sunlight

    Science.gov (United States)

    Lim, Hyon-Chol; Kim, Hun; Jang, Kyungmin; Kim, Jae-Young; Baek, Joon-Hyuck; Yang, Seung-Jin; Jeong, Sang-Hwa; Park, Jong-Rak

    2015-10-01

    We present the results of the optical design and fabrication of a light-guiding plate (LGP) that utilizes sunlight to be adopted as an illumination system for photobioreactors. A solar daylighting system was employed as the light source for the LGP. We modeled the light sources (optical fiber exit ports of the solar daylighting system), a reflection film, and LGP patterns. An LGP (1000 mm × 500 mm × 10 mm) was designed and fabricated using a computerized numerical control machine. It was optimized for the average deviation of the illuminance distribution by varying the maximum pattern spacing, minimum pattern spacing, and spacing constant of the pattern spacing function expressed in the form of an exponential function. Average illuminance and uniformity of the illuminance distribution of the fabricated LGP were measured to be 8174 lx (photon flux density: 122.0 μΕ m-2 s-1) and 90.0 %, respectively.

  15. Graphene-SnO2 composites for highly efficient photocatalytic degradation of methylene blue under sunlight.

    Science.gov (United States)

    Seema, Humaira; Christian Kemp, K; Chandra, Vimlesh; Kim, Kwang S

    2012-09-07

    Graphene sheets decorated with SnO(2) nanoparticles (RGO-SnO(2)) were prepared via a redox reaction between graphene oxide (GO) and SnCl(2). Graphene oxide (GO) was reduced to graphene (RGO) and Sn(2+) was oxidized to SnO(2) during the redox reaction, leading to a homogeneous distribution of SnO(2) nanoparticles on RGO sheets. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images show uniform distribution of the nanoparticles on the RGO surface and high-resolution transmission electron microscopy (HRTEM) shows an average particle size of 3-5 nm. The RGO-SnO(2) composite showed an enhanced photocatalytic degradation activity for the organic dye methylene blue under sunlight compared to bare SnO(2) nanoparticles. This result leads us to believe that the RGO-SnO(2) composite could be used in catalytic photodegradation of other organic dyes.

  16. Natural sunlight irradiated flower-like CuS synthesized from DMF solvothermal treatment

    Science.gov (United States)

    Zhao, Wei; Wang, Zihao; Zhou, Lei; Liu, Nianqi; Wang, Hongxing

    2016-09-01

    Three-dimensional CuS hierarchical crystals with high catalytic activity had been successfully fabricated using a facile solvothermal process. The CuS microparticles showed different flower-like morphology and good dispersion by optimizing reaction conditions. It was found that using N,N-dimethylformamide (DMF) as the solvent reagent in the proper temperature conditions was favorable for the growth of hierarchically structured CuS. The hexagonal flower-like CuS synthesized at 170°C for 60 min displayed broad-spectrum photocatalytic properties under ultraviolet (UV) and visible irradiation. The as-prepared CuS crystals exhibited good performance to decolorize methylene blue (MB) solution under visible light irradiation. The total organic carbon (TOC) removal of rhodamine B (RhB) solution was nearly 60% after 5 h of the natural sunlight irradiation, and the property was stable after testing over four recycles, demonstrating a potential application in waster water treatment.

  17. Assessment of oxidative deterioration of soybean oil at ambient and sunlight storage

    Directory of Open Access Journals (Sweden)

    Ijaz Hussain, Abdullah

    2007-12-01

    Full Text Available This study was carried out in order to probe the extent of oxidative alterations in soybean oil (SBO, subjected to ambient and sunlight storage, over a period of 180 days. The magnitude of oxidative changes was monitored by the periodical measurement of peroxide value (PV, color, free fatty acid (FFA contents, refractive index (RI, p-anisidine-, conjugated dienes-, conjugated trienes-, and iodine- values. At the end of storage period (180 days, the initial contents of FFA (0.02 % as oleic acid and PV (0.02 meq/kg of oil of the SBO samples subjected to ambient and sunlight storage reached the level of 1.77, 2.90 % and 20.52, 41.89 meq/kg of oil, respectively. The initial values of RI (40°C (1.4630, panisidine (1.10, conjugated dienes (0.08 and conjugated trienes (0.04 rose to the point of 1.4647, 1.4659; 36.13, 50.40; 23.97, 41.49 and 13.81, 19.35, respectively. Whereas, the iodine value (g of I /100 g of oil decreased from 138.00 to 126.18 and 118.04, respectively. At the end of storage period, the overall order, indicative of the oxidative changes in RI, FFA, IV, color (red + yellow, PV, P-anisidine, conjugated dienes and conjugated trienes of the SBO subjected to ambient and sunlight storage was as follows: 1.001:1.002, 1.00:1.65, 0.91:0.86, 0.80:0.60 + 0.75:0.50, 1.00:2.04, 1.00:1.39, 1.00:1.73 and 1.00:1.40, respectively. The results of various parameters investigated in the present study demonstrated the magnitude of oxidative deterioration of the SBO samples exposed to sunlight to be significantly (P Se lleva a cabo un estudio para conocer las diferencias en la oxidación del aceite de soja conservado a temperatura ambiente y a la luz solar durante un periodo de 180 días. Los cambios en la oxidación fueron evaluados mediante medidas periódicas del índice de peroxidos, color, acidez libre, índice de refracción (RI, índice de p-anisidina, dienos conjugados e índice de yodo. Al final del periodo de almacenamiento, los niveles de

  18. Sunlight effects on the 3D polar current system determined from low Earth orbit measurements

    CERN Document Server

    Laundal, Karl M; Olsen, Nils

    2016-01-01

    Interaction between the solar wind and the Earth's magnetosphere is associated with large-scale currents in the ionosphere at polar latitudes that flow along magnetic field lines (Birkeland currents) and horizontally. These current systems are tightly linked, but their global behaviors are rarely analyzed together. In this paper, we present estimates of the average global Birkeland currents and horizontal ionospheric currents from the same set of magnetic field measurements. The magnetic field measurements, from the low Earth orbiting $\\textit{Swarm}$ and CHAMP satellites, are used to co-estimate poloidal and toroidal parts of the magnetic disturbance field, represented in magnetic apex coordinates. The use of apex coordinates reduces effects of longitudinal and hemispheric variations in the Earth's main field. We present global currents from both hemispheres during different sunlight conditions. The results show that the Birkeland currents vary with the conductivity, which depends most strongly on solar EUV ...

  19. Sunlight driven photocatalytic water splitting using nanostructured bismuth tungstate (Bi2WO6)

    Science.gov (United States)

    Radha, R.; Sakar, M.; Bharathkumar, S.; Balakumar, S.

    2017-05-01

    Sunlight driven photocatalytic water splitting properties of nanosized Bi2WO6 have been demonstrated. Upon the structural confirmation using XRD and Raman studies, the band edge offset deduced from UV-DRS spectra showed that the energy band structure of Bi2WO6 is manifested due to electronic transition in the hybridized orbital of Bi6s and O2p to the W5d orbital. The observed Bi2WO6 nanoparticulates-assisted H2 generation from glycerol-water mixture may be attributed to the following two competitive phenomena: (i) the photocatalytic degradation of glycerol and (ii) photocatalytic splitting of water molecules, where glycerol acts as a sacrificial agent. This study sheds lights on the photocatalytic reformation of contaminated aqueous ecosystems as a green resource to produce hydrogen energy.

  20. Retrieval of stratospheric aerosol size information from OSIRIS limb scattered sunlight spectra

    Directory of Open Access Journals (Sweden)

    A. E. Bourassa

    2008-02-01

    Full Text Available Recent work has shown that the retrieval of stratospheric aerosol vertical profiles is possible using limb scattered sunlight measurements at optical wavelengths. The aerosol number density profile is retrieved for an assumed particle size distribution and composition. This result can be used to derive the extinction at the measured wavelength. However, large systematic error can result from the uncertainty in the assumed size distribution when the result is used to estimate the extinction at other wavelengths. It is shown in this work that the addition of information obtained from the near infrared limb radiance profile at 1530 nm measured by the imaging module of the OSIRIS instrument yields an indication of the aerosol size distribution profile that can be used to improve the fidelity of the retrievals. A comparison of the estimated extinction profile at 1020 nm with coincident occultation measurements demonstrates agreement to within approximately 15% from 12 to 27 km altitude.

  1. Star Cluster Dissolution in Arp 284

    CERN Document Server

    Peterson, Bradley W; Smith, Beverly J; Hancock, Mark

    2009-01-01

    We present results from a study of proto-globular cluster candidates in the interacting galaxy system Arp 284 (NGC 7714/5). Studies of the Antennae and M51 have suggested that the majority of these star clusters dissolve within 20 Myr due to mass loss. We obtain cluster colors using archival \\emph{HST} data, and estimate ages and extinctions for over 150 clusters using evolutionary synthesis models. We find that clusters in NGC 7714 are generally less than 20 Myr old, while the data in the bridge is too limited to allow good estimates for individual clusters. We also examine {H {\\sc ii}} region complexes with lower-resolution \\emph{GALEX} and ground-based H$\\alpha$ images. Several of these regions appear to be much older than the detected clusters within them, which may indicate the presence of an older, unresolved population of low mass or dispersed clusters.

  2. Personalized microbial network inference via co-regularized spectral clustering

    NARCIS (Netherlands)

    Imangaliyev, S.; Keijser, B.; Crielaard, W.; Tsivtsivadze, E.

    2015-01-01

    We use Human Microbiome Project (HMP) cohort (Peterson et al., 2009) to infer personalized oral microbial networks of healthy individuals. To determine clustering of individuals with similar microbial profiles, co-regularized spectral clustering algorithm is applied to the dataset. For each cluster

  3. Personalized microbial network inference via co-regularized spectral clustering

    NARCIS (Netherlands)

    Imangaliyev, S.; Keijser, B.J.; Crielaard, W.; Tsivtsivadze, E.; Zheng, H.; Hu, X.; Berrar, D.; Wang, Y.; Dubitzky, W.; Hao, J.K.; Cho, K.H.; Gilbert, D.

    2014-01-01

    We use Human Microbiome Project (HMP) cohort [1] to infer personalized oral microbial networks of healthy individuals. To determine clustering of individuals with similar microbial profiles, co-regularized spectral clustering algorithm is applied to the dataset. For each cluster we discovered, we co

  4. Personalized microbial network inference via co-regularized spectral clustering

    NARCIS (Netherlands)

    Imangaliyev, S.; Keijser, B.; Crielaard, W.; Tsivtsivadze, E.

    2015-01-01

    We use Human Microbiome Project (HMP) cohort (Peterson et al., 2009) to infer personalized oral microbial networks of healthy individuals. To determine clustering of individuals with similar microbial profiles, co-regularized spectral clustering algorithm is applied to the dataset. For each cluster

  5. Cluster Radioactivity

    Science.gov (United States)

    Poenaru, Dorin N.; Greiner, Walter

    One of the rare examples of phenomena predicted before experimental discovery, offers the opportunity to introduce fission theory based on the asymmetric two center shell model. The valleys within the potential energy surfaces are due to the shell effects and are clearly showing why cluster radioactivity was mostly detected in parent nuclei leading to a doubly magic lead daughter. Saddle point shapes can be determined by solving an integro-differential equation. Nuclear dynamics allows us to calculate the half-lives. The following cluster decay modes (or heavy particle radioactivities) have been experimentally confirmed: 14C, 20O, 23F, 22,24-26Ne, 28,30Mg, 32,34Si with half-lives in good agreement with predicted values within our analytical superasymmetric fission model. The preformation probability is calculated as the internal barrier penetrability. An universal curve is described and used as an alternative for the estimation of the half-lives. The macroscopic-microscopic method was extended to investigate two-alpha accompanied fission and true ternary fission. The methods developed in nuclear physics are also adapted to study the stability of deposited atomic clusters on the planar surfaces.

  6. Analysis of Environmental Effects on Leaf Temperature under Sunlight, High Pressure Sodium and Light Emitting Diodes.

    Directory of Open Access Journals (Sweden)

    Jacob A Nelson

    Full Text Available The use of LED technology is commonly assumed to result in significantly cooler leaf temperatures than high pressure sodium technology. To evaluate the magnitude of this effect, we measured radiation incident to and absorbed by a leaf under four radiation sources: clear sky sunlight in the field, sunlight in a glass greenhouse, and indoor plants under either high pressure sodium or light emitting diodes. We then applied a common mechanistic energy-balance model to compare leaf to air temperature difference among the radiation sources and environments. At equal photosynthetic photon flux, our results indicate that the effect of plant water status and leaf evaporative cooling is much larger than the effect of radiation source. If plants are not water stressed, leaves in all four radiation sources were typically within 2°C of air temperature. Under clear sky conditions, cool sky temperatures mean that leaves in the field are always cooler than greenhouse or indoor plants-when photosynthetic photon flux, stomatal conductance, wind speed, vapor pressure deficit, and leaf size are equivalent. As water stress increases and cooling via transpiration decreases, leaf temperatures can increase well above air temperature. In a near-worst case scenario of water stress and low wind, our model indicates that leaves would increase 6°, 8°, 10°, and 12°C above air temperature under field, LED, greenhouse, and HPS scenarios, respectively. Because LED fixtures emit much of their heat through convection rather than radiative cooling, they result in slightly cooler leaf temperatures than leaves in greenhouses and under HPS fixtures, but the effect of LED technology on leaf temperature is smaller than is often assumed. Quantifying the thermodynamic outputs of these lamps, and their physiological consequences, will allow both researchers and the horticulture industry to make informed decisions when employing these technologies.

  7. The relationship between long-term sunlight radiation and cognitive decline in the REGARDS cohort study

    Science.gov (United States)

    Kent, Shia T.; Kabagambe, Edmond K.; Wadley, Virginia G.; Howard, Virginia J.; Crosson, William L.; Al-Hamdan, Mohammad Z.; Judd, Suzanne E.; Peace, Fredrick; McClure, Leslie A.

    2014-04-01

    Sunlight may be related to cognitive function through vitamin D metabolism or circadian rhythm regulation. The analysis presented here sought to test whether ground and satellite measures of solar radiation are associated with cognitive decline. The study used a 15-year residential history merged with satellite and ground monitor data to determine sunlight (solar radiation) and air temperature exposure for a cohort of 19,896 cognitively intact black and white participants aged 45+ from the 48 contiguous United States. Exposures of 15, 10, 5, 2, and 1-year were used to predict cognitive status at the most recent assessment in logistic regression models; 1-year insolation and maximum temperatures were chosen as exposure measures. Solar radiation interacted with temperature, age, and gender in its relationships with incident cognitive impairment. After adjustment for covariates, the odds ratio (OR) of cognitive decline for solar radiation exposure below the median vs above the median in the 3rd tertile of maximum temperatures was 1.88 (95 % CI: 1.24, 2.85), that in the 2nd tertile was 1.33 (95 % CI: 1.09, 1.62), and that in the 1st tertile was 1.22 (95 % CI: 0.92, 1.60). We also found that participants under 60 years old had an OR = 1.63 (95 % CI: 1.20, 2.22), those 60-80 years old had an OR = 1.18 (95 % CI: 1.02, 1.36), and those over 80 years old had an OR = 1.05 (0.80, 1.37). Lastly, we found that males had an OR = 1.43 (95 % CI: 1.22, 1.69), and females had an OR = 1.02 (0.87, 1.20). We found that lower levels of solar radiation were associated with increased odds of incident cognitive impairment.

  8. The effect of sunlight exposure on interleukin-6 levels in depressive and non-depressive subjects.

    Science.gov (United States)

    Levandovski, Rosa; Pfaffenseller, Bianca; Carissimi, Alicia; Gama, Clarissa S; Hidalgo, Maria Paz Loayza

    2013-03-05

    The objective of this epidemiological study was to evaluate the effect of length of sunlight exposure on interleukin 6 (IL-6) levels in depressive and non-depressive subjects. This was a cross-sectional study with 154 subjects (54 males, mean age: 43.5 ± 12.8 years) who were living in a rural area in south Brazil. Chronobiological and light parameters were assessed using the Munich Chronotype Questionnaire. Sleep quality was evaluated using the Pittsburgh Sleep Quality Index. Depressive symptoms were assessed with the Beck Depression Inventory. Plasma levels of inflammatory cytokines (IL-2, IL-4, IL-6, IL-10, tumor necrosis factor-α, and interferon) were collected during the daytime and measured. IL-6 levels showed a positive correlation with light exposure (r = 0.257; p exposure was an independent factor for predicting IL-6 levels (ß = 0.26; p = 0.002). In non-depressed subjects, exposure to a different intensity of light did not affect IL-6 levels (t = -1.6; p = 0.1). However, when the two depressive groups with low and high light exposure were compared, the low light exposure group had lower levels of IL-6 compared with the high light exposure group (t = -2.19 and p = 0.0037). The amount of time that participants are exposed to sunlight is directly related to their IL-6 levels. Additionally, depressed subjects differ in their IL-6 levels if they are exposed to light for differing amounts of time.

  9. Recovery of hexavalent chromium from water using photoactive TiO2-montmorillonite under sunlight

    Directory of Open Access Journals (Sweden)

    Ridha Djellabi

    2016-04-01

    Full Text Available Hexavalent chromium was removed from water under sunlight using a synthesized TiO2-montmorillonite (TiO2-M employing tartaric acid as a hole scavenger. Cr(VI species was then reduced to Cr(III species by electrons arising from TiO2 particles. After that, the produced Cr(III species  was transferred to montmorillonite  due to electrostatic attractions leading to  set free TiO2 particles for a further Cr(VI species reduction. Furthermore, produced Cr(III, after Cr(VI reduction, does not  penetrate into the solution. The results indicate that no dark adsorption of Cr(VI species on TiO2-M is present, however, the reduction of Cr(VI species under sunlight increased strongly as a function of tartaric acid concentration up to 60 ppm, for which the extent of reduction is maximum within 3 h. On the other hand, the reduction extent of Cr(VI species is maximum with an initial concentration of Cr(VI species lower than 30 ppm by the use of 0.2 g/L of TiO2-M. Nevertheless, the increase of the Cr(VI initial concentration led to increase the amount of Cr(VI species reduced (capacity of reduction until a Cr(VI concentration of 75 and 100 ppm, for which  it remained constant at around 221 mg/g. For comparison, the increase of Cr(VI species concentration in the case of the commercial TiO2 P25 under the same conditions exhibited its deactivation when the reduced amount decreased from 198.1 to 157.6 mg/g as the concentration increased from 75 to 100 ppm.

  10. Sunlight-exposed biofilm microbial communities are naturally resistant to chernobyl ionizing-radiation levels.

    Science.gov (United States)

    Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

    2011-01-01

    The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general diversity patterns, despite increased mutation levels at the single

  11. Sensitivity Studies for Space-based Measurement of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

    Science.gov (United States)

    Mao, Jianping; Kawa, S. Randolph

    2003-01-01

    A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 microns. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the radiance signal or sensitivity to CO2 change near the surface is not significantly diminished even in the presence of aerosols and/or thin cirrus clouds in the atmosphere; (c) the modification of sunlight path length by scattering of aerosols and cirrus clouds could lead to large systematic errors in the retrieval; therefore, ancillary aerosol/cirrus cloud data are important to reduce retrieval errors; (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature; (e) the atmospheric path length, over which the CO2 absorption occurs, must be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

  12. Mg-doped ZnO nanoparticles for efficient sunlight-driven photocatalysis.

    Science.gov (United States)

    Etacheri, Vinodkumar; Roshan, Roshith; Kumar, Vishwanathan

    2012-05-01

    Magnesium-doped ZnO (ZMO) nanoparticles were synthesized through an oxalate coprecipitation method. Crystallization of ZMO upon thermal decomposition of the oxalate precursors was investigated using differential scanning calorimetry (DSC) and X-ray diffraction (XRD) techniques. XRD studies point toward a significant c-axis compression and reduced crystallite sizes for ZMO samples in contrast to undoped ZnO, which was further confirmed by HRSEM studies. X-ray photoelectron spectroscopy (XPS), UV/vis spectroscopy and photoluminescence (PL) spectroscopy were employed to establish the electronic and optical properties of these nanoparticles. (XPS) studies confirmed the substitution of Zn(2+) by Mg(2+), crystallization of MgO secondary phase, and increased Zn-O bond strengths in Mg-doped ZnO samples. Textural properties of these ZMO samples obtained at various calcination temperatures were superior in comparison to the undoped ZnO. In addition to this, ZMO samples exhibited a blue-shift in the near band edge photoluminescence (PL) emission, decrease of PL intensities and superior sunlight-induced photocatalytic decomposition of methylene blue in contrast to undoped ZnO. The most active photocatalyst 0.1-MgZnO obtained after calcination at 600 °C showed a 2-fold increase in photocatalytic activity compared to the undoped ZnO. Band gap widening, superior textural properties and efficient electron-hole separation were identified as the factors responsible for the enhanced sunlight-driven photocatalytic activities of Mg-doped ZnO nanoparticles.

  13. Modeling of integrated sunlight velocity measurements: The effect of surface darkening by magnetic fields

    Science.gov (United States)

    Ulrich, R. K.; Henney, C. J.; Schimpf, S.; Fossat, E.; Gelly, B.; Grec, G.; Loudagh, S.; Schmider, F.-X; Palle, P.; Regulo, C.

    1993-01-01

    It has been known since the work by Claverie et al. (1982) that integrated-sunlight velocities measured with the resonance scattering technique show variations with time scales of weeks to months. The cause can be understood in terms of the effects of solar activity as was pointed out by Edmunds & Gough (1983) and Andersen & Maltby (1983). The latter authors included a model calculation based on sunspot areas which showed good promise of being able to quantitatively reproduce the observed velocity shifts. We discuss in this paper a new modeling effort based on daily magnetograms obtained at the 150-ft tower on Mt. Wilson. This type of database is more quantitative than sunspot area. Similar maps of magnetically sensitive quantities will be measured on a continuous time base as part of several planned helioseismology experiments (from space with the Solar Oscillations Imagery/Michelson Doppler Imager (SOI/MDI) experiment on the Solar and Heliospheric Observatory (SOHO), see Scherrer et al. (1991) or with ground-based networks, see Hill & Leibacher (1991)). We discuss the correlations between various magnetically sensitive quantities and develop a new model for the effects of magnetic field on line profiles and surface brightness. From these correlations we integrate the line profile changes over the solar surface using observed magnetic field strengths measured at lambda 5250.2. The final output is a new model for the effects of magnetic fields on integrated sunlight velocities which we compare with daily offset velocities derived from the International Research on the Interior of the Sun (IRIS)-T instrument at the Observatorio del Teide.

  14. Abiotic degradation of four phthalic acid esters in aqueous phase under natural sunlight irradiation

    Institute of Scientific and Technical Information of China (English)

    Ruttapol Lertsirisopon; Satoshi Soda; Kazunari Sei; Michihiko Ike

    2009-01-01

    Abiotic degradability of four phthalic acid esters (PAEs) in the aquatic phase was evaluated over the wide pH range (5-9). The PAE solutions in glass test tubes were placed in the dark and under natural sunlight irradiation for evaluating the degradation rate via hydrolysis and photolysis plus hydrolysis, respectively, at ambient temperature for 140 d from autumn to winter in Osaka, Japan. The efficiency of abiotic degradation of the PAEs with relatively short alkyl chain, butylbenzyl phthalate (BBP) and di-n-butyl phthalate (DBP) at neutral pH was significant less than that in the acidic or alkaline condition. Photolysis was considered to mainly contribute to total abiotic degradation at any pH. Neither hydrolysis nor photolysis of di-ethylhexyl phthalate (DEHP) proceeded significantly at any pH, especially hydrolysis at neutral pH was negligible. On the other hand, the degradation rate of di-isononyl phthalate (DINP) mainly catalyzed by photolysis was much higher compared with that of the other PAEs, and almost complete removal was observed during the experimental period at pH 5.0 and 9.0. As a whole, according to the half-life (t1/2) obtained in the experiments, the abiotic degradability of the PAEs was in the sequence, DINP (32-140 d) > DBP (50-360 d), BBP (58-480 d) > DEHP (390-1600 d) under sunlight irradiation (via photolysis plus hydrolysis). Although the abiotic degradation rate for BBP, DBP, and DEHP are much lower than their biodegradation rate reported, the photolysis rate for DINP is comparable to its biodegradation rate in the acidic or alkaline condition.

  15. Effect of season and sunlight on viral kinetics during hepatitis C virus therapy

    Science.gov (United States)

    Hernández-Alvarez, Noemi; Pascasio Acevedo, Juan Manuel; Quintero, Enrique; Fernández Vázquez, Inmaculada; García-Eliz, María; de la Revilla Negro, Juan; Crespo García, Javier; Hernández-Guerra, Manuel

    2017-01-01

    Background and aims Rapid viral response (RVR) during antiviral treatment for hepatitis C virus (HCV) predicts sustained viral response (SVR). Recently, vitamin D levels have been associated with SVR. As sunlight is the most important source of vitamin D and shows seasonal variation, we evaluated the effect of season on viral kinetics during peginterferon/ribavirin-based therapy for HCV. Methods Consecutive HCV patients treated with peginterferon/ribavirin and boceprevir/ telaprevir (June 2011–July 2014) were included. Patients were grouped according to season when therapy was initiated (Season A: May–October and Season B: November–April) depending on hours of daily sunlight. Multiple logistic regression analysis included factors known to influence SVR to treatment. The dependent variables were undetectable viral load (VL) or VL ≤15 UI/mL (VL ≤15) at weeks 4, 8 and 12, end of treatment and SVR. Results The study included 930 patients (66.8% men; median 54 years) treated with telaprevir (n=537) or boceprevir, without (n=481) or with lead-in therapy of peginterferon/ribavirin. Baseline characteristics of patients in Season A (45.3%, n=421) and Season B groups were similar. Overall, a higher rate of RVR (23.5% vs 16.1%, p=0.005) and VL ≤15 (51.0% vs 38.6%, p≤0.001) was observed in patients starting treatment during Season A versus Season B. By logistic regression analysis, initiating treatment in Season A proved to be an independent predictor of RVR and VL ≤15. Conclusions In our setting, seasonality affects viral kinetics in HCV genotype 1 patients treated with peginterferon/ribavirin-based therapy. Our findings support the hypothesis that vitamin D influences viral response to peginterferon/ribavirin-based therapy.

  16. Rapid synthesis of nanocrystalline magnesium chromite and ferrite ceramics with concentrated sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Michalsky, Ronald, E-mail: michalskyr@ethz.ch; Peterson, Brian A.; Pfromm, Peter H.

    2014-04-01

    Highlights: • Refractory ceramics are produced via rapid solar-thermal processing. • The formed chromite and ferrite spinels have a high specific surface area. • The presence of transition metal oxides enables reduction of Mg cations. • Dinitrogen is reduced only by chromium. • The spinels are stable in reducing environments and in the presence of solar radiation. - Abstract: High-temperature refractory ceramics and catalysts such as MgM{sub 2}O{sub 4} (M = Cr, Fe) are produced conventionally via energy-intensive solid-state syntheses (using 0.44–10 GJ electricity for sintering per ton oxide, equivalent to combustion of 48–1088 kg coal per ton oxide). This article reports rapid production of 17 ± 2 mol% MgFe{sub 2}O{sub 4} and 8.6 ± 0.9 mol% MgCr{sub 2}O{sub 4} after 30 min at 1200 °C employing 0.82 kW m{sup −2} sunlight concentrated at a geometric ratio of about 900 m{sup 2} m{sup −2} using a Fresnel lens. Solar radiation promotes the diffusion-limited ferrite formation (42 ± 5 μmol MgFe{sub 2}O{sub 4} per mol Fe{sub 2}O{sub 3} s{sup −1} vs. 26 ± 3 μmol mol{sup −1} s{sup −1} in absence of sunlight) while the transition metals promote the reduction of Mg{sup 2+}. The nanocrystalline and macroporous spinel has a specific surface area of 9.7–11.9 m{sup 2} g{sup −1} (in the order of sol–gel synthesis methods) and is stable under extreme conditions, i.e., high temperature, solar radiation, and reducing agents.

  17. The SMART CLUSTER METHOD - adaptive earthquake cluster analysis and declustering

    Science.gov (United States)

    Schaefer, Andreas; Daniell, James; Wenzel, Friedemann

    2016-04-01

    Earthquake declustering is an essential part of almost any statistical analysis of spatial and temporal properties of seismic activity with usual applications comprising of probabilistic seismic hazard assessments (PSHAs) and earthquake prediction methods. The nature of earthquake clusters and subsequent declustering of earthquake catalogues plays a crucial role in determining the magnitude-dependent earthquake return period and its respective spatial variation. Various methods have been developed to address this issue from other researchers. These have differing ranges of complexity ranging from rather simple statistical window methods to complex epidemic models. This study introduces the smart cluster method (SCM), a new methodology to identify earthquake clusters, which uses an adaptive point process for spatio-temporal identification. Hereby, an adaptive search algorithm for data point clusters is adopted. It uses the earthquake density in the spatio-temporal neighbourhood of each event to adjust the search properties. The identified clusters are subsequently analysed to determine directional anisotropy, focussing on a strong correlation along the rupture plane and adjusts its search space with respect to directional properties. In the case of rapid subsequent ruptures like the 1992 Landers sequence or the 2010/2011 Darfield-Christchurch events, an adaptive classification procedure is applied to disassemble subsequent ruptures which may have been grouped into an individual cluster using near-field searches, support vector machines and temporal splitting. The steering parameters of the search behaviour are linked to local earthquake properties like magnitude of completeness, earthquake density and Gutenberg-Richter parameters. The method is capable of identifying and classifying earthquake clusters in space and time. It is tested and validated using earthquake data from California and New Zealand. As a result of the cluster identification process, each event in

  18. PHAT Stellar Cluster Survey. II. Andromeda Project Cluster Catalog

    CERN Document Server

    Johnson, L Clifton; Dalcanton, Julianne J; Wallace, Matthew L; Simpson, Robert J; Lintott, Chris J; Kapadia, Amit; Skillman, Evan D; Caldwell, Nelson; Fouesneau, Morgan; Weisz, Daniel R; Williams, Benjamin F; Beerman, Lori C; Gouliermis, Dimitrios A; Sarajedini, Ata

    2015-01-01

    We construct a stellar cluster catalog for the Panchromatic Hubble Andromeda Treasury (PHAT) survey using image classifications collected from the Andromeda Project citizen science website. We identify 2,753 clusters and 2,270 background galaxies within ~0.5 deg$^2$ of PHAT imaging searched, or ~400 kpc$^2$ in deprojected area at the distance of the Andromeda galaxy (M31). These identifications result from 1.82 million classifications of ~20,000 individual images (totaling ~7 gigapixels) by tens of thousands of volunteers. We show that our crowd-sourced approach, which collects >80 classifications per image, provides a robust, repeatable method of cluster identification. The high spatial resolution Hubble Space Telescope images resolve individual stars in each cluster and are instrumental in the factor of ~6 increase in the number of clusters known within the survey footprint. We measure integrated photometry in six filter passbands, ranging from the near-UV to the near-IR. PHAT clusters span a range of ~8 ma...

  19. CLUSTER SYNCHRONIZATION IN A COMPLEX DYNAMICAL NETWORK WITH TWO NONIDENTICAL CLUSTERS

    Institute of Scientific and Technical Information of China (English)

    Liang CHEN; Jun'an LU

    2008-01-01

    This paper further investigates cluster synchronization in a complex dynamical network with two-cluster. Each cluster contains a number of identical dynamical systems, however, the sub-systems composing the two clusters can be different, i.e., the individual dynamical system in one cluster can differ from that in the other cluster. Complete synchronization within each cluster is possible only if each node from one cluster receives the same input from nodes in other cluster. In this case, the stability condition of one-cluster synchronization is known to contain two terms: the first accounts for the contribution of the inner-cluster coupling structure while the second is simply an extra linear term, which can be deduced by the "same-input" condition. Applying the connection graph stability method, the authors obtain an upper bound of input strength for one cluster if the first account is known, by which the synchronizability of cluster can be scaled. For different clusters, there are different upper bound of input strength by virtue of different dynamics and the corresponding cluster structure. Moreover, two illustrative examples are presented and the numerical simulations coincide with the theoretical analysis.

  20. Chronic Condition Clusters and Polypharmacy among Adults

    Directory of Open Access Journals (Sweden)

    Ami Vyas

    2012-01-01

    Full Text Available Objective. The primary objective of the study was to estimate the rates of polypharmacy among individuals with multimorbidity defined as chronic condition clusters and examine their associations with polypharmacy. Methods. Cross-sectional analysis of 10,528 individuals of age above 21, with at least one physical condition in cardiometabolic (diabetes or heart disease or hypertension, musculoskeletal (arthritis or osteoporosis, and respiratory (chronic obstructive pulmonary disease (COPD or asthma clusters from the 2009 Medical Expenditure Panel Survey. Chi-square tests and logistic regressions were performed to analyze the association between polypharmacy and multimorbidity. Results. Polypharmacy rates varied from a low of 7.2% among those with respiratory cluster to a high of 64.1% among those with all three disease clusters. Among those with two or more disease clusters, the rates varied from 28.3% for musculoskeletal and respiratory clusters to 41.8% for those with cardiometabolic and respiratory clusters. Individual with cardiometabolic conditions alone or in combination with other disease clusters were more likely to have polypharmacy. Compared to those with musculoskeletal and respiratory conditions, those with cardiometabolic and respiratory conditions had 1.68 times higher likelihood of polypharmacy. Conclusions. Rates of polypharmacy differed by specific disease clusters. Individuals with cardiometabolic condition were particularly at high risk of polypharmacy, suggesting greater surveillance for adverse drug interaction in this group.

  1. Serum levels of vitamin D, sunlight exposure, and knee cartilage loss in older adults: the Tasmanian older adult cohort study.

    Science.gov (United States)

    Ding, Changhai; Cicuttini, Flavia; Parameswaran, Venkat; Burgess, John; Quinn, Steve; Jones, Graeme

    2009-05-01

    To determine the associations between serum levels of vitamin D, sunlight exposure, and knee cartilage loss cross-sectionally and longitudinally in older adults. A total of 880 randomly selected subjects (mean age 61 years [range 51-79 years], 50% women) were studied at baseline, and 353 of these subjects were studied 2.9 years later. Serum levels of 25-hydroxyvitamin D (25[OH]D) were assessed by radioimmunoassay, and sunlight exposure was assessed by questionnaire. T1-weighted fat-suppressed magnetic resonance imaging (MRI) of the right knee was performed to determine knee cartilage volume and defects. Knee radiographic osteoarthritis (OA) and knee pain were also assessed. The mean 25(OH)D serum level was 52.8 nmoles/liter at baseline (range 13-119 nmoles/liter). Winter sunlight exposure and serum 25(OH)D level were both positively associated with medial and lateral tibial cartilage volume, and a serum 25(OH)D levelSunlight exposure and serum 25(OH)D levels are both associated with decreased knee cartilage loss (assessed by radiograph or MRI). This is best observed using the whole range of 25(OH)D levels rather than predefined cut points and implies that achieving vitamin D sufficiency may prevent and/or retard cartilage loss in knee OA.

  2. Photodegradation of pharmaceuticals in the aquatic environment by sunlight and UV-A, -B and -C irradiation.

    Science.gov (United States)

    Kawabata, Kohei; Sugihara, Kazumi; Sanoh, Seigo; Kitamura, Shigeyuki; Ohta, Shigeru

    2013-01-01

    In order to investigate the effect of sunlight on the persistence and ecotoxicity of pharmaceuticals contaminating the aquatic environment, we exposed nine pharmaceuticals (acetaminophen (AA), amiodarone (AM), dapsone (DP), dexamethasone (DX), indomethacin (IM), naproxen (NP), phenytoin (PH), raloxifene (RL), and sulindac (SL)) in aqueous media to sunlight and to ultraviolet (UV) irradiation at 254, 302 or 365 nm (UV-C, UV-B or UV-A, respectively). Degradation of the pharmaceuticals was monitored by means of high-performance liquid chromatography (HPLC). Sunlight completely degraded AM, DP and DX within 6 hr, and partly degraded the other pharmaceuticals, except AA and PH, which were not degraded. Similar results were obtained with UV-B, while UV-A was less effective (both UV-A and -B are components of sunlight). All the pharmaceuticals were photodegraded by UV-C, which is used for sterilization in sewage treatment plants. Thus, the photodegradation rates of pharmaceuticals are dependent on both chemical structure and the wavelength of UV exposure. Toxicity assay using the luminescent bacteria test (ISO11348) indicated that UV irradiation reduced the toxicity of some pharmaceuticals to aquatic organisms by decreasing their amount (photodegradation) and increased the toxicity of others by generating toxic photoproduct(s). These results indicate the importance of investigating not only parent compounds, but also photoproducts in the risk assessment of pharmaceuticals in aquatic environments.

  3. Photocatalytic degradation of humic substances in aqueous solution using Cu-doped ZnO nanoparticles under natural sunlight irradiation.

    Science.gov (United States)

    Maleki, Afshin; Safari, Mahdi; Shahmoradi, Behzad; Zandsalimi, Yahya; Daraei, Hiua; Gharibi, Fardin

    2015-11-01

    In this study, Cu-doped ZnO nanoparticles were investigated as an efficient synthesized catalyst for photodegradation of humic substances in aqueous solution under natural sunlight irradiation. Cu-doped ZnO nanocatalyst was prepared through mild hydrothermal method and was characterized using FT-IR, powder XRD and SEM techniques. The effect of operating parameters such as doping ratio, initial pH, catalyst dosage, initial concentrations of humic substances and sunlight illuminance were studied on humic substances degradation efficiency. The results of characterization analyses of samples confirmed the proper synthesis of Cu-doped ZnO nanocatalyst. The experimental results indicated the highest degradation efficiency of HS (99.2%) observed using 1.5% Cu-doped ZnO nanoparticles at reaction time of 120 min. Photocatalytic degradation efficiency of HS in a neutral and acidic pH was much higher than that at alkaline pH. Photocatalytic degradation of HS was enhanced with increasing the catalyst dosage and sunlight illuminance, while increasing the initial HS concentration led to decrease in the degradation efficiency of HS. Conclusively, Cu-doped ZnO nanoparticles can be used as a promising and efficient catalyst for degradation of HS under natural sunlight irradiation.

  4. Diffused sunlight driven highly synergistic pathway for complete mineralization of organic contaminants using reduced graphene oxide supported photocatalyst.

    Science.gov (United States)

    Babu, Sundaram Ganesh; Ramalingam Vinoth; Neppolian, Bernaurdshaw; Dionysiou, Dionysios D; Ashokkumar, Muthupandian

    2015-06-30

    Diffused sunlight is found to be an effective light source for the efficient degradation and mineralization of organic pollutant (methyl orange as a probe) by sono-photocatalytic degradation using reduced graphene oxide (rGO) supported CuO-TiO2 photocatalyst. The prepared catalysts are characterized by XRD, XPS, UV-vis DRS, PL, photoelectrochemical, SEM-EDS and TEM. A 10 fold synergy is achieved for the first time by combining sonochemical and photocatalytic degradation under diffused sunlight. rGO loading augments the activity of bare CuO-TiO2 more than two fold. The ability of rGO in storing, transferring, and shuttling electrons at the heterojunction between TiO2 and CuO facilitates the separation of photogenerated electron-hole pairs, as evidenced by the photoluminescence results. The complete mineralization of MO and the by-products within a short span of time is confirmed by TOC analysis. Further, hydroxyl radical mediated degradation under diffused sunlight is confirmed by LC-MS. This system shows similar activity for the degradation of methylene blue and 4-chlorophenol indicating the versatility of the catalyst for the degradation of various pollutants. This investigation is likely to open new possibilities for the development of highly efficient diffused sunlight driven TiO2 based photocatalysts for the complete mineralization of organic contaminants.

  5. Degradation of methyl and ethyl mercury by singlet oxygen generated from sea water exposed to sunlight or ultraviolet light.

    Science.gov (United States)

    Suda, I; Suda, M; Hirayama, K

    1993-01-01

    Photodegradation of methyl mercury (MeHg) and ethyl Hg (EtHg) in sea water was studied by sunlight or ultraviolet (UV) light exposure, and by determining inorganic Hg produced by degradation. Sea water containing 1 microM MeHg or EtHg was exposed to sunlight or UV light. N-Acetyl-L-cysteine was added to the solution for preventing Hg loss during the light exposure. MeHg and EtHg in sea water were degraded by sunlight (> 280 nm), UV light A (320-400 nm) and UV light B (280-320 nm), though the amounts of inorganic Hg produced from MeHg were 1/6th to 1/12th those from EtHg. Inorganic Hg production was greater with increasing concentration of sea water. Degradation of MeHg and EtHg by the UV light A exposure was inhibited by singlet oxygen (1O2) trappers such as NaN3, 1,4-diazabicyclo[2,2,2]octane, histidine, methionine and 2,5-dimethylfuran. On the other hand, inhibitors or scavengers of superoxide anion, hydrogen peroxide or hydroxyl radical did not inhibit the photodegradation of alkyl Hg. These results suggested that 1O2 generated from sea water exposed to sunlight, UV light A or UV light B was the reactive oxygen species mainly responsible for the degradation of MeHg and EtHg.

  6. A simple relationship between the sunlight concentration factor and the thermal conductance in a class of photothermal engines

    Energy Technology Data Exchange (ETDEWEB)

    Rocha-Martinez, J.A.; Navarrete-Gonzalez, T.D. [Area de Fisica, Dept. de Ciencias Basicas, Universidad Autonoma Metropolitana Azcapotzalco, Mexico (Mexico); Angulo-Brown, F. [Departaamento de Fisica, Escuela Superior de Fisica y Matematicas, Instituto Politecnico Nacional, Mexico (Mexico)

    1998-07-21

    In this brief paper we present an addendum to a recently published analysis of a photothermal engine model. Here, we numerically demonstrate that the design parameters, the sunlight concentration factor and the thermal conductances of materials employed as thermal conductors are linked by a simple relationship, if one wishes to obtain the maximization of the power output of the photothermal engine. (author)

  7. A revised moving cluster distance to the Pleiades open cluster

    CERN Document Server

    Galli, P A B; Bouy, H; Bouvier, J; Olivares, J; Teixeira, R

    2016-01-01

    Aims: We provide a new distance estimate for the Pleiades based on the moving cluster method, which will be useful to further discuss the so-called Pleiades distance controversy and compare it with the very precise parallaxes from the Gaia space mission. Methods: We apply a refurbished implementation of the convergent point search method to an updated census of Pleiades stars to calculate the convergent point position of the cluster from stellar proper motions. Then, we derive individual parallaxes for 64 cluster members using radial velocities compiled from the literature, and approximate parallaxes for another 1146 stars based on the spatial velocity of the cluster. This represents the largest sample of Pleiades stars with individual distances to date. Results: The parallaxes derived in this work are in good agreement with previous results obtained in different studies (excluding Hipparcos) for individual stars in the cluster. We report a mean parallax of $7.44\\pm 0.08$~mas and distance of $134.4^{+2.9}_{-2...

  8. Effectiveness of sensor monitoring in an occupational therapy rehabilitation program for older individuals after hip fracture, the SO-HIP trial: : study protocol of a three-arm stepped wedge cluster randomized trial

    NARCIS (Netherlands)

    Pol, Margriet C; Ter Riet, Gerben; van Hartingsveldt, Margo; Kröse, Ben; de Rooij, Sophia E; Buurman, Bianca M

    2017-01-01

    BACKGROUND: The performance of activities of daily living (ADL) at home is important for the recovery of older individuals after hip fracture. However, 20-90% of these individuals lose ADL function and never fully recover. It is currently unknown to what extent occupational therapy (OT) with coachin

  9. Weathering patterns of polycyclic aromatic hydrocarbons contained in submerged Deepwater Horizon oil spill residues when re-exposed to sunlight.

    Science.gov (United States)

    John, Gerald F; Han, Yuling; Clement, T Prabhakar

    2016-12-15

    The Deepwater Horizon (DWH) oil spill event released a large amount of sweet crude oil into the Gulf of Mexico (GOM). An unknown portion of this oil that arrived along the Alabama shoreline interacted with nearshore sediments and sank forming submerged oil mats (SOMs). A considerable amount of hydrocarbons, including polycyclic aromatic hydrocarbons (PAHs), were trapped within these buried SOMs. Recent studies completed using the oil spill residues collected along the Alabama shoreline have shown that several PAHs, especially higher molecular weight PAHs (four or more aromatic rings), are slowly weathering compared to the weathering levels experienced by the oil when it was floating over the GOM. In this study we have hypothesized that the weathering rates of PAHs in SOMs have slowed down because the buried oil was isolated from direct exposure to sunlight, thus hindering the photodegradation pathway. We further hypothesized that re-exposing SOMs to sunlight can reactivate various weathering reactions. Also, SOMs contain 75-95% sand (by weight) and the entrapped sand could either block direct sunlight or form large oil agglomerates with very little exposed surface area; these processes could possibly interfere with weathering reactions. To test these hypotheses, we completed controlled experiments to study the weathering patterns of PAHs in a field recovered SOM sample after re-exposing it to sunlight. Our experimental results show that the weathering levels of several higher molecular weight PAHs have slowed down primarily due to the absence of sunlight-induced photodegradation reactions. The data also show that sand particles in SOM material could potentially interfere with photodegradation reactions.

  10. Sunlight exposure and cardiovascular risk factors in the REGARDS study: a cross-sectional split-sample analysis.

    Science.gov (United States)

    Kent, Shia T; Cushman, Mary; Howard, George; Judd, Suzanne E; Crosson, William L; Al-Hamdan, Mohammad Z; McClure, Leslie A

    2014-06-19

    Previous research has suggested that vitamin D and sunlight are related to cardiovascular outcomes, but associations between sunlight and risk factors have not been investigated. We examined whether increased sunlight exposure was related to improved cardiovascular risk factor status. Residential histories merged with satellite, ground monitor, and model reanalysis data were used to determine previous-year sunlight radiation exposure for 17,773 black and white participants aged 45+ from the US. Exploratory and confirmatory analyses were performed by randomly dividing the sample into halves. Logistic regression models were used to examine relationships with cardiovascular risk factors. The lowest, compared to the highest quartile of insolation exposure was associated with lower high-density lipoprotein levels in adjusted exploratory (-2.7 mg/dL [95% confidence interval: -4.2, -1.2]) and confirmatory (-1.5 mg/dL [95% confidence interval: -3.0, -0.1]) models. The lowest, compared to the highest quartile of insolation exposure was associated with higher systolic blood pressure levels in unadjusted exploratory and confirmatory, as well as the adjusted exploratory model (2.3 mmHg [95% confidence interval: 0.8, 3.8]), but not the adjusted confirmatory model (1.6 mg/dL [95% confidence interval: -0.5, 3.7]). The results of this study suggest that lower long-term sunlight exposure has an association with lower high-density lipoprotein levels. However, all associations were weak, thus it is not known if insolation may affect cardiovascular outcomes through these risk factors.

  11. Mitochondrial tolerance to single and repeat exposure to simulated sunlight in human epidermal and dermal skin cells.

    Science.gov (United States)

    Kelly, J; Murphy, J E J

    2016-12-01

    Sunlight represents the primary threat to mitochondrial integrity in skin given the unique nature of the mitochondrial genome and its proximity to the electron transport chain. The accumulation of mitochondrial DNA (mtDNA) mutations is a key factor in many human pathologies and this is linked to key roles of mitochondrial function in terms of energy production and cell regulation. The main objective of this study was to evaluate solar radiation induced changes in mitochondrial integrity, function and dynamics in human skin cells using a Q-Sun solar simulator to deliver a close match to the intensity of summer sunlight. Spontaneously immortalised human skin epidermal keratinocytes (HaCaT) and Human Dermal Fibroblasts (HDFn) were divided into two groups. Group A were irradiated once and Group B twice 7days apart and evaluated using cell survival, viability and mitochondrial membrane potential (MMP) and mass at 1, 4 and 7days post one exposure for Group A and 1, 4, 7 and 14days post second exposure for Group B. Viability and survival of HaCaT and HDFn cells decreased after repeat exposure to Simulated Sunlight Irradiation (SSI) with no recovery. HDFn cells showed no loss in MMP after one or two exposures to SSI compared to HaCaT cells which showed a periodic loss of MMP after one exposure with a repeat exposure causing a dramatic decrease from which cells did not recover. Mitochondrial Mass in exposed HDFn cells was consistent with control after one or two exposures to SSI; however mitochondrial mass was significantly decreased in HaCaT cells. Data presented here suggests that mitochondria in epidermal cells are more sensitive to sunlight damage compared to mitochondria in dermal cells, despite their origin, confirming a skin layer specific sensitivity to sunlight, but not as expected. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Diffused sunlight driven highly synergistic pathway for complete mineralization of organic contaminants using reduced graphene oxide supported photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Babu, Sundaram Ganesh; Ramalingam Vinoth [SRM Research Institute, SRM University, Kattankulathur 603203, Chennai, Tamilnadu (India); Neppolian, Bernaurdshaw, E-mail: neppolian.b@res.srmuniv.ac.in [SRM Research Institute, SRM University, Kattankulathur 603203, Chennai, Tamilnadu (India); Dionysiou, Dionysios D. [Environmental Engineering and Science Program, Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, Cincinnati, OH 45221-0012 (United States); Ashokkumar, Muthupandian [The School of Chemistry, University of Melbourne, Parkville, Melbourne, Victoria 3010 (Australia)

    2015-06-30

    Highlights: • Diffused sunlight is firstly used as an effective source for the degradation of organics. • More than 10 fold synergistic effect is achieved by sono-photocatalysis. • rGO enhances the degradation efficiency up to 54% as compared with CuO–TiO{sub 2} alone. • Plausible mechanism and intermediates formed are supported with experimental studies. - Abstract: Diffused sunlight is found to be an effective light source for the efficient degradation and mineralization of organic pollutant (methyl orange as a probe) by sono-photocatalytic degradation using reduced graphene oxide (rGO) supported CuO–TiO{sub 2} photocatalyst. The prepared catalysts are characterized by XRD, XPS, UV–vis DRS, PL, photoelectrochemical, SEM-EDS and TEM. A 10 fold synergy is achieved for the first time by combining sonochemical and photocatalytic degradation under diffused sunlight. rGO loading augments the activity of bare CuO–TiO{sub 2} more than two fold. The ability of rGO in storing, transferring, and shuttling electrons at the heterojunction between TiO{sub 2} and CuO facilitates the separation of photogenerated electron–hole pairs, as evidenced by the photoluminescence results. The complete mineralization of MO and the by-products within a short span of time is confirmed by TOC analysis. Further, hydroxyl radical mediated degradation under diffused sunlight is confirmed by LC–MS. This system shows similar activity for the degradation of methylene blue and 4-chlorophenol indicating the versatility of the catalyst for the degradation of various pollutants. This investigation is likely to open new possibilities for the development of highly efficient diffused sunlight driven TiO{sub 2} based photocatalysts for the complete mineralization of organic contaminants.

  13. An Automatic Clustering Technique for Optimal Clusters

    CERN Document Server

    Pavan, K Karteeka; Rao, A V Dattatreya; 10.5121/ijcsea.2011.1412

    2011-01-01

    This paper proposes a simple, automatic and efficient clustering algorithm, namely, Automatic Merging for Optimal Clusters (AMOC) which aims to generate nearly optimal clusters for the given datasets automatically. The AMOC is an extension to standard k-means with a two phase iterative procedure combining certain validation techniques in order to find optimal clusters with automation of merging of clusters. Experiments on both synthetic and real data have proved that the proposed algorithm finds nearly optimal clustering structures in terms of number of clusters, compactness and separation.

  14. Disinfection of Airborne Organisms by Ultraviolet-C Radiation and Sunlight

    Science.gov (United States)

    2012-07-01

    cytoplasm contain UV radiation-absorbing proteins. 2. The majority of bacterial spores identified at high altitudes contain pigments such as...3 4. BACTERIAL ENDOSPORES...10 6. Single (left) and approximately 4 µm clustered (right) bacterial spores ...............16 7. A

  15. Individual Education.

    Science.gov (United States)

    Corsini, Raymond

    1981-01-01

    Paper presented at the 66th Convention of the International Association of Pupil Personnel Workers, October 20, 1980, Baltimore, Maryland, describes individual education based on the principles of Alfred Adler. Defines six advantages of individual education, emphasizing student responsibility, mutual respect, and allowing students to progress at…

  16. Individual Education.

    Science.gov (United States)

    Corsini, Raymond

    1981-01-01

    Paper presented at the 66th Convention of the International Association of Pupil Personnel Workers, October 20, 1980, Baltimore, Maryland, describes individual education based on the principles of Alfred Adler. Defines six advantages of individual education, emphasizing student responsibility, mutual respect, and allowing students to progress at…

  17. Exposure to sunlight reduces the risk of myopia in rhesus monkeys.

    Science.gov (United States)

    Wang, Yong; Ding, Hui; Stell, William K; Liu, Liangping; Li, Saiqun; Liu, Hongshan; Zhong, Xingwu

    2015-01-01

    Exposure to sunlight has recently been postulated as responsible for the effect that more time spent outdoors protects children from myopia, while early life exposure to natural light was reported to be possibly related to onset of myopia during childhood. In this study, we had two aims: to determine whether increasing natural light exposure has a protective effect on hyperopic defocus-induced myopia, and to observe whether early postnatal exposure to natural light causes increased risk of refractive error in adolescence. Eight rhesus monkeys (aged 20-30 days) were treated monocularly with hyperopic-defocus (-3.0D lens) and divided randomly into two groups: AL group (n=4), reared under Artificial (indoor) Lighting (08:00-20:00); and NL group (n=4), exposed to Natural (outdoor) Light for 3 hours per day (11:00-14:00), and to indoor lighting for the rest of the light phase. After being reared with lenses for ca. 190 days, all monkeys were returned to unrestricted vision until the age of 3 years. Another eight age-matched monkeys, reared with unrestricted vision under artificial lighting since birth, were employed as controls. The ocular refraction, corneal curvature and axial dimensions were measured before lens-wearing (at 23±3 days of age), monthly during the light phase, and at the age of puberty (at 1185+3 days of age). During the lens-wearing treatment, infant monkeys in the NL group were more hyperopic than those in the AL group (F=5.726, P=0.032). Furthermore, the two eyes of most NL monkeys remained isometropic, whereas 3 of 4 AL monkeys developed myopic anisometropia more than -2.0D. At adolescence, eyes of AL monkeys showed significant myopic anisometropia compared with eyes of NL monkeys (AL vs NL: -1.66±0.87D vs -0.22±0.44D; P=0.002) and controls (AL vs Control: -1.66±0.87D vs -0.05±0.85D; Pexposure to natural outdoor light might have an effect to reduced hyperopic defocus-induced myopia. Also, the data imply that early life exposure to sunlight may

  18. Sunlight-Exposed Biofilm Microbial Communities Are Naturally Resistant to Chernobyl Ionizing-Radiation Levels

    Science.gov (United States)

    Ragon, Marie; Restoux, Gwendal; Moreira, David; Møller, Anders Pape; López-García, Purificación

    2011-01-01

    Background The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. Methodology/Principal Findings To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta) and ascomycete fungi (Ascomycota) dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU) present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. Conclusions/Significance Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in terms of general

  19. Sunlight-exposed biofilm microbial communities are naturally resistant to chernobyl ionizing-radiation levels.

    Directory of Open Access Journals (Sweden)

    Marie Ragon

    Full Text Available BACKGROUND: The Chernobyl accident represents a long-term experiment on the effects of exposure to ionizing radiation at the ecosystem level. Though studies of these effects on plants and animals are abundant, the study of how Chernobyl radiation levels affect prokaryotic and eukaryotic microbial communities is practically non-existent, except for a few reports on human pathogens or soil microorganisms. Environments enduring extreme desiccation and UV radiation, such as sunlight exposed biofilms could in principle select for organisms highly resistant to ionizing radiation as well. METHODOLOGY/PRINCIPAL FINDINGS: To test this hypothesis, we explored the diversity of microorganisms belonging to the three domains of life by cultivation-independent approaches in biofilms developing on concrete walls or pillars in the Chernobyl area exposed to different levels of radiation, and we compared them with a similar biofilm from a non-irradiated site in Northern Ireland. Actinobacteria, Alphaproteobacteria, Bacteroidetes, Acidobacteria and Deinococcales were the most consistently detected bacterial groups, whereas green algae (Chlorophyta and ascomycete fungi (Ascomycota dominated within the eukaryotes. Close relatives to the most radio-resistant organisms known, including Rubrobacter species, Deinococcales and melanized ascomycete fungi were always detected. The diversity of bacteria and eukaryotes found in the most highly irradiated samples was comparable to that of less irradiated Chernobyl sites and Northern Ireland. However, the study of mutation frequencies in non-coding ITS regions versus SSU rRNA genes in members of a same actinobacterial operational taxonomic unit (OTU present in Chernobyl samples and Northern Ireland showed a positive correlation between increased radiation and mutation rates. CONCLUSIONS/SIGNIFICANCE: Our results show that biofilm microbial communities in the most irradiated samples are comparable to non-irradiated samples in

  20. A revised moving cluster distance to the Pleiades open cluster

    Science.gov (United States)

    Galli, P. A. B.; Moraux, E.; Bouy, H.; Bouvier, J.; Olivares, J.; Teixeira, R.

    2017-01-01

    Context. The distance to the Pleiades open cluster has been extensively debated in the literature over several decades. Although different methods point to a discrepancy in the trigonometric parallaxes produced by the Hipparcos mission, the number of individual stars with known distances is still small compared to the number of cluster members to help solve this problem. Aims: We provide a new distance estimate for the Pleiades based on the moving cluster method, which will be useful to further discuss the so-called Pleiades distance controversy and compare it with the very precise parallaxes from the Gaia space mission. Methods: We apply a refurbished implementation of the convergent point search method to an updated census of Pleiades stars to calculate the convergent point position of the cluster from stellar proper motions. Then, we derive individual parallaxes for 64 cluster members using radial velocities compiled from the literature, and approximate parallaxes for another 1146 stars based on the spatial velocity of the cluster. This represents the largest sample of Pleiades stars with individual distances to date. Results: The parallaxes derived in this work are in good agreement with previous results obtained in different studies (excluding Hipparcos) for individual stars in the cluster. We report a mean parallax of 7.44 ± 0.08 mas and distance of pc that is consistent with the weighted mean of 135.0 ± 0.6 pc obtained from the non-Hipparcos results in the literature. Conclusions: Our result for the distance to the Pleiades open cluster is not consistent with the Hipparcos catalog, but favors the recent and more precise distance determination of 136.2 ± 1.2 pc obtained from Very Long Baseline Interferometry observations. It is also in good agreement with the mean distance of 133 ± 5 pc obtained from the first trigonometric parallaxes delivered by the Gaia satellite for the brightest cluster members in common with our sample. Full Table B.2 is only

  1. The cluster bootstrap consistency in generalized estimating equations

    KAUST Repository

    Cheng, Guang

    2013-03-01

    The cluster bootstrap resamples clusters or subjects instead of individual observations in order to preserve the dependence within each cluster or subject. In this paper, we provide a theoretical justification of using the cluster bootstrap for the inferences of the generalized estimating equations (GEE) for clustered/longitudinal data. Under the general exchangeable bootstrap weights, we show that the cluster bootstrap yields a consistent approximation of the distribution of the regression estimate, and a consistent approximation of the confidence sets. We also show that a computationally more efficient one-step version of the cluster bootstrap provides asymptotically equivalent inference. © 2012.

  2. Typical Industrial Cluster - Chemistry/refinery/petrochemistry

    OpenAIRE

    Bungener, Stéphane Laurent

    2016-01-01

    A refinery and petrochemical site are described in the document. Data for the steam consumption and production of the cluster's process units are also described. The cluster can be broken down into two individual sites made up of process units and process utility requirements.

  3. Heavy hitters via cluster-preserving clustering

    DEFF Research Database (Denmark)

    Larsen, Kasper Green; Nelson, Jelani; Nguyen, Huy L.

    2016-01-01

    , providing correctness whp. In fact, a simpler version of our algorithm for p = 1 in the strict turnstile model answers queries even faster than the "dyadic trick" by roughly a log n factor, dominating it in all regards. Our main innovation is an efficient reduction from the heavy hitters to a clustering...... problem in which each heavy hitter is encoded as some form of noisy spectral cluster in a much bigger graph, and the goal is to identify every cluster. Since every heavy hitter must be found, correctness requires that every cluster be found. We thus need a "cluster-preserving clustering" algorithm......, that partitions the graph into clusters with the promise of not destroying any original cluster. To do this we first apply standard spectral graph partitioning, and then we use some novel combinatorial techniques to modify the cuts obtained so as to make sure that the original clusters are sufficiently preserved...

  4. New photocatalyst based on graphene oxide/chitin for degradation of dyes under sunlight.

    Science.gov (United States)

    Wang, Yuntao; Pei, Yaqiong; Xiong, Wenfei; Liu, Tingguo; Li, Jing; Liu, Shilin; Li, Bin

    2015-11-01

    Sunlight photocatalyst was fabricated by in situ synthesis of Cu2O in the regenerated chitin (RC)/graphene oxide (GO) composite film, where the porous chitin film was used as the microreactor for the formation of nano Cu2O. Nano Cu2O was immobilized and evenly distributed in the matrix and Cu2O tended to grow on the GO sheets. Cu2O inside the matrix excite and generate free photoelectrons and electron holes, which was responsible for the degradation of dyes, while GO transferred the yielded photoelectrons to prevent the generation of local high potential zone and induce the chain degradation at more points. So it was found that the porous chitin film could load Cu2O and graphene at the same time, controlling the size of Cu2O and leading to easy recycle and reuse of the photocatalyst. Moreover, the introduction of GO has dramatically improved the photocatalytic activity of Cu2O in the Cu2O/GO/RC film, showing great potential application in wastewater treatment utilizing solar energy.

  5. Mycorrhiza symbiosis increases the surface for sunlight capture in Medicago truncatula for better photosynthetic production.

    Directory of Open Access Journals (Sweden)

    Lisa Adolfsson

    Full Text Available Arbuscular mycorrhizal (AM fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi, and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM, mock inoculum (control or with P(i fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with P(i fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased P(i supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and P(i-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by P(i fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and P(i-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area.

  6. Photocatalytic oxidation of acetonitrile in aqueous suspension of titanium dioxide irradiated by sunlight

    Energy Technology Data Exchange (ETDEWEB)

    Augugliaro, V.; Bianco Prevot, A.; Caceres Vazquez, J.; Garcia-Lopez, E.; Irico, A.; Loddo, V.; Malato Rodriguez, S.; Marci, G.; Palmisano, L.; Pramauro, E.

    2002-07-01

    The photocatalytic oxidation of acetonitrile (CH{sub 3}CN) was carried out in aqueous suspensions of polycrystalline UiO{sub 2} P25 Degussa irradiated by sunlight. A plus flow photoreactor in a total recycle loop was used for carrying out reactivity experiments in which the concentrations of acetonitrile, of its intermediate oxidation products and of not-purgeable organic carbon (NPOC) were monitored. The influence of the presence of strong oxidant species (H{sub 2}O{sub 2}, S{sub 2}O{sub 8}, CIO) on the process rate was studied. The dependence of acetonitrile photo-oxidation rate on the substrate concentration and on the catalyst amount was also investigated. The photodegradation rate of substrate and NPOC follows a first order kinetics with respect to acetonitrile and NPOC concentrations, respectively. The presence of S{sub {sup O}8}''2- and solar irradiation determines the occurrence of homogeneous degradation of acetonitrile and NPOC. In the presence of irradiated catalyst, a significant synergetic effect is observed for NPOC degradation while for the acetonitrile oxidation this effect is not evident. H{sub 2}O{sub 2} does not effect the process while CIO negatively affects the acetonitrile oxidation rate and it seems to inhibit the NPOC degradation. (Author) 20 refs.

  7. A comparison of hip fracture incidence rates among elderly in Sweden by latitude and sunlight exposure.

    Science.gov (United States)

    Nilson, Finn; Moniruzzaman, Syed; Andersson, Ragnar

    2014-03-01

    Research has shown that hip fracture risk increases with latitude; hypothetically due to reduced sunlight exposure and its effect on bone quality. Sweden, with large differences in latitude and UV radiation, is ideal to study in order to analyse the association between latitude and UV radiation on age- and sex-specific hip fracture rates among elderly. Aggregated (2006-2008) age- and sex-specific hip fracture data was obtained for each Swedish municipality as well as the municipality's latitudinal coordinates and aggregated (2006-2008) UV radiation levels. Pearson correlations were calculated between hip fracture incidence rates, latitude and UV radiation. Independent t tests were calculated on tertile-categorized latitudinal data in order to investigate the difference in hip fracture risk between these categories. Statistically significant correlations were seen in all groups between hip fracture incidence rates and latitude as well as UV radiation. The independent t tests showed that this correlation was mainly due to high incidence rates in high latitude municipalities. Statistically significant correlations are seen between hip fracture incidence rates and latitude as well as UV radiation in Sweden and the northern parts of Sweden have an increased risk of hip fractures compared to the middle and southern parts. To our knowledge this is the first study using a national discharge register that shows this relationship and provides a starting point for further research to investigate why populations in northern Sweden have a higher risk of hip fractures compared to other Swedish regions.

  8. Seasonal effects on pterygium surgery outcome: implications for the role of sunlight exposure.

    Science.gov (United States)

    Sul, Sabahattin; Korkmaz, Şafak; Novruzlu, Şahin

    2014-05-01

    The aim of this study was to compare the results of pterygium surgery in patients when performed in the summer with the results of surgery performed in the winter. This retrospective study enrolled 55 eyes of 53 patients with primary pterygia who underwent a surgery between December 2011 and January 2012 (winter group, 32 eyes) or between June and July 2012 (summer group, 23 eyes). All the patients were followed up for at least 1 year. Pterygium recurrence, ocular discomfort, persistent conjunctival inflammation, and graft complications were evaluated postoperatively. There was no significant difference between the groups in terms of age or gender. All the patients were farmers in rural areas. The overall pterygium recurrence rate was 14.5% (8 of 55 eyes). The recurrence rate in the summer group was significantly higher than in the winter group (26.1% vs. 6.2%, P = 0.048). Persistent conjunctival inflammation was also significantly higher in the summer group than in the winter group (30.4% vs. 6.2%, P = 0.022). Pterygium recurrence was significantly higher in eyes with persistent conjunctival inflammation than in eyes without inflammation (66.6% vs. 4.3%, P exposure to sunlight during the summer.

  9. Effect of preadmission sunlight exposure on intensive care unit-acquired delirium: a multicenter study.

    Science.gov (United States)

    Simons, Koen S; Workum, Jessica D; Slooter, Arjen J C; van den Boogaard, Mark; van der Hoeven, Johannes G; Pickkers, Peter

    2014-04-01

    It is assumed that there is a relation between light exposure and delirium incidence. The aim of our study was to determine the effect of prehospital light exposure on the incidence of intensive care unit (ICU)-acquired delirium. Data from 3 ICUs in the Netherlands were analyzed retrospectively. Delirium was assessed with the Confusion Assessment Method for the ICU. Daily light intensity data were obtained from meteorological stations in the vicinity of the 3 hospitals. The association between light intensity and delirium incidence was analyzed using logistic regression analysis adjusting for known covariates for delirium. Data of 3198 patients, aged (mean ± SD) 61.9 ± 15.3 years with Acute Physiology and Chronic Health Evaluation II score 16.4 ± 6.6 were analyzed. Delirium incidence was 31.2% and did not vary significantly throughout the year. Twenty-eight-day preadmission photoperiod was highest in spring and lowest in winter; however, no association between light exposure and delirium incidence was found (odds ratio, 1.00; 95% confidence interval, 0.99-1.00; P = 0.72). Furthermore, delirium was significantly associated with age, infection, use of sedatives, Acute Physiology and Chronic Health Evaluation II score, and diagnosis of neurological disease or trauma. The incidence of delirium does not differ per season and prior sunlight exposure does not play a role of importance in the development of ICU-acquired delirium. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. First field-based atmospheric observation of the reduction of reactive mercury driven by sunlight

    Science.gov (United States)

    de Foy, Benjamin; Tong, Yindong; Yin, Xiufeng; Zhang, Wei; Kang, Shichang; Zhang, Qianggong; Zhang, Guoshuai; Wang, Xuejun; Schauer, James J.

    2016-06-01

    Hourly speciated measurements of atmospheric mercury made in a remote, high-altitude site in the Tibetan Plateau revealed the first field observations of the reduction of reactive mercury in the presence of sunlight in the atmosphere. Measurements were collected over four winter months on the shore of Nam Co Lake in the inland Tibetan Plateau. The data was analyzed to identify sources and atmospheric transformations of the speciated mercury compounds. The absence of local anthropogenic sources provided a unique opportunity to examine chemical transformations of mercury. An optimization algorithm was used to determine the parameters of a chemical box model that would match the measured reactive mercury concentrations. This required the presence of a photolytic reduction reaction previously observed in laboratory studies and in power plant plumes. In addition, the model estimated the role of vertical mixing in diluting reactive gaseous mercury during the day, and the role of bromine chemistry in oxidizing gaseous elemental mercury to produce reactive gaseous mercury. This work provides further evidence of the need to add the photolytic reduction reaction of oxidized mercury into atmospheric transport models in order to better simulate mercury deposition.

  11. Photolysis of Antibiotics under Simulated Sunlight Irradiation: Identification of Photoproducts by High-Resolution Mass Spectrometry.

    Science.gov (United States)

    Baena-Nogueras, Rosa María; González-Mazo, Eduardo; Lara-Martín, Pablo A

    2017-02-28

    There is growing concern regarding the widespread use of antibiotics and their presence in the aqueous environment. Their removal in the water column is mediated by different types of degradation processes for which the mechanisms are still unclear. This research is focused on characterizing the photodegradation kinetics and pathways of two largely employed antibiotics families: sulfonamides (9 SDs) and fluoroquinolones (6 FQs). Degradation percentages and rates were measured in pure water exposed to simulated natural sunlight at a constant irradiance value (500 W m(-2)) during all the experiments, and the main photoproducts formed were characterized through accurate mass measurement using ultraperformance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-QToF-MS). Over 200 different phototransformation products were identified for SDs and FQs, 66% of them, to the best of our knowledge, have not been described before. Their sequential formation and disappearance over the course of the experiments reveals the existence of several pathways for the degradation of target antibiotics. Occurrence of new photoproducts derived from desulfonation and/or denitrification, as well as hydroxylation of photo-oxidized heterocyclic rings, have been identified during photodegradation of SDs, whereas a new pathway yielding oxidation of the benzene ring after the cleavage of the piperazine ring (e.g., CIP product with m/z 280) is described for FQs.

  12. On identifying the specular reflection of sunlight in earth-monitoring satellite data.

    Energy Technology Data Exchange (ETDEWEB)

    Nelsen, James M., Jr.; Hohlfelder, Robert James; Jackson, Dale Clayton; Longenbaugh, Randolph S.

    2009-03-01

    Among the background signals commonly seen by Earth-monitoring satellites is the specular reflection of sunlight off of Earth's surface, commonly referred to as a glint. This phenomenon, involving liquid or ice surfaces, can result in the brief, intense illumination of satellite sensors appearing from the satellite perspective to be of terrestrial origin. These glints are important background signals to be able to identify with confidence, particularly in the context of analyzing data from satellites monitoring for transient surface or atmospheric events. Here we describe methods for identifying glints based on the physical processes involved in their production, including spectral fitting and polarization measurements. We then describe a tool that, using the WGS84 spheroidal Earth model, finds the latitude and longitude on Earth where a reflection of this type could be produced, given input Sun and satellite coordinates. This tool enables the user to determine if the surface at the solution latitude and longitude is in fact reflective, thus identifying the sensor response as a true glint or an event requiring further analysis.

  13. Sunlight activated lanthanide complex for luminescent solar collector applications: effect of waveguide matrix

    Science.gov (United States)

    Shahi, Praveen Kumar; Singh, Priyam; Bahadur Rai, Shyam

    2017-02-01

    The performance of Eu(DBM)3Phen complex (EDP) dispersed in PMMA poly-(methyl methacrylate) polymer matrix, as simple planner luminescent solar collectors (LSCs) is demonstrated using spectroscopic and photovoltaic (PV) measurements. The organic ligands absorb ultra-violet-blue (UV-blue) radiation (220–450 nm) very efficiently and transfer its energy to the Eu3+ ion, which gives an intense red emission even in sunlight exposure. The excellent optical properties of EDP in PMMA permit its coating on the front surface of c-Si solar cell (10  ×  10 cm2) for PV measurements. The PV characterizations reveal the improvement in the short circuit current density (J sc) of PV cell and maximum improvement is found to be 4.6% for 2.5 wt% EDP concentration in PMMA matrix. The efficiency of solar cell increases from 17.22% to 18.33% for bare and 2.5% EDP in PMMA. At a higher concentration of EDP, the thin film starts losing its transparency and hence PV efficiency decreases. These results illustrate that a EDP complex combined with a PV cell could work as a prototype of a new generation solar cell.

  14. The influence of short-term exposure to tropical sunlight on boar seminal characteristics

    Science.gov (United States)

    Egbunike, G. N.; Dede, T. I.

    1980-06-01

    The seminal characteristics of 4 Large White boars exposed to direct tropical sunlight 45 min daily for three days were compared to those of their mates that were maintained under shade in the barn. During the period of exposure, both respiratory rate and rectal temperature increased significantly by 276.84 and 5.13% respectively in the exposed over the unexposed boars, thus indicating a high degree of hyperthermia. Although libido, as judged from the reaction time, was unaffected, the ejaculation time appeared to be longer for the stressed than unstressed animals. Gel mass, semen volume and pH appeared to be stable inspite of the treatment, unlike sperm motility and concentration which deteriorated. Also, the dehydrogenase activity of the semen was inferior in the stressed animals. Sperm output per ejaculate dropped drastically only in the week following exposure from 58.22 to 28.42 billion sperm as compared to corresponding values of 54.83 and 47.87 by the unexposed boars. Similarly, the frequency of sperm abnormality was higher in the stressed boars in this period after which the animals appeared to have recovered.

  15. Degradation of triclosan in the presence of p-aminobenzoic acid under simulated sunlight irradiation.

    Science.gov (United States)

    Zhai, Pingping; Chen, Xuan; Dong, Wenbo; Li, Hongjing; Chovelon, Jean-Marc

    2017-01-01

    This study aimed to investigate the degradation of triclosan (TCS) in the presence of p-aminobenzoic acid (PABA) under simulated sunlight irradiation (λ ≥ 290 nm). The effect of PABA concentration, pH, dissolved organic matter (DOM), and DOM-hydrolytic Fe(III) species complexes on the photodegradation of TCS in the presence of PABA (TCS-PABA) was also studied. The photolysis of TCS-PABA obeyed pseudo-first-order kinetics well, and the degradation of TCS-PABA enhanced with increasing solution pH (from 3.0 to 11.0). The presence of PABA inhibited the degradation of TCS-PABA, and the weakest inhibitory effect was observed while the concentration of PABA was 5 mg L(-1). The addition of DOM (Suwannee River fulvic acid standard I [SRFA], Suwannee River HA standard II [SRHA], and Suwannee River natural organic matter [SRNOM]) showed different inhibition effects on TCS-PABA degradation. However, higher Fe(III) concentration at the DOM concentration of 5 mg L(-1) could favor the formation of DOM-hydrolytic Fe(III) species complexes, further accelerating the degradation of TCS-PABA. In comparison with deionized water (DI water), TCS-PABA could be better photodegraded in river water nearby the effluent of a wastewater treatment plant. This study provides useful information for understanding the natural behavior of TCS in the presence of other organic contaminants.

  16. Photodegradation of malachite green under natural sunlight irradiation: kinetic and toxicity of the transformation products.

    Science.gov (United States)

    Pérez-Estrada, L A; Agüera, A; Hernando, M D; Malato, S; Fernández-Alba, A R

    2008-02-01

    This article describes the photolytic degradation of malachite green (MG), a cationic triphenylmethane dye used worldwide as a fungicide and antiseptic in the aquaculture industry. Photolysis experiments were performed by direct exposure of a solution of MG in water to natural sunlight. The main transformation products (TPs) generated during the process were identified by liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) and gas chromatography mass spectrometry (GC-MS). The 28 TPs identified with this strategy indicate that MG undergoes three main reactions, N-demethylation, hydroxylation and cleavage of the conjugated structure forming benzophenone derivatives. These processes involve hydroxyl radical attack on the phenyl ring, the N,N-dimethylamine group and the central carbon atom. The Vibrio fischeri acute toxicity test showed that the solution remains toxic after MG has completely disappeared. This toxicity could be assigned, at least in part, to the formation of 4-(dimethylamine)benzophenone, which has an EC(50,30 min) of 0.061 mg l(-1), and is considered "very toxic to aquatic organisms" by current EU legislation.

  17. Photocatalytic degradation of phenol by iodine doped tin oxide nanoparticles under UV and sunlight irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Al-Hamdi, Abdullah M.; Sillanpää, Mika [Laboratory of Green Chemistry, Lappeenranta University of Technology, Sammonkatu 12, 50130 Mikkeli (Finland); Dutta, Joydeep, E-mail: dutta@squ.edu.om [Chair in Nanotechnology, Water Research Center, Sultan Qaboos University, P.O. Box 17, 123 Al-Khoudh (Oman)

    2015-01-05

    Highlights: • A sol–gel method used to synthesize tin oxide nanoparticles. • Nanoparticles of tin oxide doped with different iodine concentrations. • Degradation studies carried up with UV–vis, TOC, HPLC and GC instruments. • 1% iodine doped tin dioxide showed maximum photodegradation efficiency. - Abstract: Iodine doped tin oxide (SnO{sub 2}:I) nanoparticles were prepared by sol–gel synthesis and their photocatalytic activities with phenol as a test contaminant were studied. In the presence of the catalysts, phenol degradation under direct sunlight was comparable to what was achieved under laboratory conditions. Photocatalytic oxidation reactions were studied by varying the catalyst loading, light intensity, illumination time, pH of the reactant and phenol concentration. Upon UV irradiation in the presence of SnO{sub 2}:I nanoparticles, phenol degrades very rapidly within 30 min, forming carboxylic acid which turns the solution acidic. Phenol degradation rate with 1% iodine doped SnO{sub 2} nanoparticles is at least an order of magnitude higher compared to the degradation achieved through undoped SnO{sub 2} nanoparticles under similar illumination conditions.

  18. Degradation of the pesticide carbofuran on clay and soil surfaces upon sunlight exposure.

    Science.gov (United States)

    Mountacer, H; Atifi, A; Wong-Wah-Chung, P; Sarakha, M

    2014-03-01

    In the present study, the photolysis of carbofuran has been undertaken under sunlight conditions and at the surface of model supports such as clay films and different soils collected from two different sites in Morocco (Tirs and Dahs). In all conditions, an efficient degradation occurred owing to direct light absorption and also to photoinduced processes involving either clays or natural organic matter moities. On kaolin films, the photodegradation kinetics appears to follow a first-order process that clearly depends on the film thickness. The diffusion of carbofuran from the lower part to the illuminated surface was found to be negligible when compared to the photolysis process within the range of 20-70 μm. Thus, the photolysis rate constant at the surface of the solid support, k (0), was evaluated to be 7.0 × 10(-3) min(-1). Under these experimental conditions, the quantum yield was found equal to 2.1 × 10(-4). On soil surfaces, the disappearance rate constant was mainly attributed to photoinduced processes arising from natural organic matter. From the analytical point of view, the products were formed through (1) hydroxylation on the aromatic ring, (2) homolytic scission of the carbamate C-O bond leading to radical species formation, and (3) photohydrolysis of the carbamate C-O bond.

  19. Sunlight-Driven Hydrogen Formation by Membrane-Supported Photoelectrochemical Water Splitting

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, Nathan S. [California Institute of Technology

    2014-03-26

    This report describes the significant advances in the development of the polymer-supported photoelectrochemical water-splitting system that was proposed under DOE grant number DE-FG02-05ER15754. We developed Si microwire-array photoelectrodes, demonstrated control over the material and light-absorption properties of the microwire-array photoelectrodes, developed inexpensive processes for synthesizing the arrays, and doped the arrays p-type for use as photocathodes. We also developed techniques for depositing metal-nanoparticle catalysts of the hydrogen-evolution reaction (HER) on the wire arrays, investigated the stability and catalytic performance of the nanoparticles, and demonstrated that Ni-Mo alloys are promising earth-abundant catalysts of the HER. We also developed methods that allow reuse of the single-crystalline Si substrates used for microwire growth and methods of embedding the microwire photocathodes in plastic to enable large-scale processing and deployment of the technology. Furthermore we developed techniques for controlling the structure of WO3 films, and demonstrated that structural control can improve the quantum yield of photoanodes. Thus, by the conclusion of this project, we demonstrated significant advances in the development of all components of a sunlight-driven membrane-supported photoelectrochemical water-splitting system. This final report provides descriptions of some of the scientific accomplishments that were achieved under the support of this project and also provides references to the peer-reviewed publications that resulted from this effort.

  20. The sensitivity to polarization in stratospheric aerosol retrievals from limb scattered sunlight measurements

    Science.gov (United States)

    Elash, B. J.; Bourassa, A. E.; Rieger, L. A.; Dueck, S. R.; Zawada, D. J.; Degenstein, D. A.

    2017-03-01

    Satellite measurements of limb scattered sunlight at visible and near infrared wavelengths have been used successfully for several years to retrieve the vertical profile of stratospheric aerosol extinction coefficient. The existing satellite measurements are of the total radiance, with very little knowledge or impact of the polarization state of the limb radiance. Recently proposed instrument concepts for stratospheric aerosol profiling have been designed to measure the linearly polarized radiance. Yet, to date, the impact of the polarized measurement on the retrievals has not been systematically studied. Here we use a fully spherical, multiple scattering radiative transfer model to perform a sensitivity study on the effects of the polarized measurement on stratospheric aerosol extinction retrievals through specific investigations of the aerosol signal fraction in polarized measurements, potential retrieval bias, and achievable precision. In this study,we simulate both total and linearly polarized measurements, for a wide range of limb viewing geometries that are encountered in typical low earth orbits and for various aerosol loading scenarios. The orientation of the linear polarization with respect to the horizon is also studied. Taking into account instrument signal to noise levels it is found that in general, the linear polarization can be used as effectively as the total radiance measurement, with consideration of instrument signal to noise capabilities; however the horizontal polarization is more promising in terms of signal magnitude.

  1. Mycorrhiza symbiosis increases the surface for sunlight capture in Medicago truncatula for better photosynthetic production.

    Science.gov (United States)

    Adolfsson, Lisa; Solymosi, Katalin; Andersson, Mats X; Keresztes, Áron; Uddling, Johan; Schoefs, Benoît; Spetea, Cornelia

    2015-01-01

    Arbuscular mycorrhizal (AM) fungi play a prominent role in plant nutrition by supplying mineral nutrients, particularly inorganic phosphate (Pi), and also constitute an important carbon sink. AM stimulates plant growth and development, but the underlying mechanisms are not well understood. In this study, Medicago truncatula plants were grown with Rhizophagus irregularis BEG141 inoculum (AM), mock inoculum (control) or with P(i) fertilization. We hypothesized that AM stimulates plant growth through either modifications of leaf anatomy or photosynthetic activity per leaf area. We investigated whether these effects are shared with P(i) fertilization, and also assessed the relationship between levels of AM colonization and these effects. We found that increased P(i) supply by either mycorrhization or fertilization led to improved shoot growth associated with increased nitrogen uptake and carbon assimilation. Both mycorrhized and P(i)-fertilized plants had more and longer branches with larger and thicker leaves than the control plants, resulting in an increased photosynthetically active area. AM-specific effects were earlier appearance of the first growth axes and increased number of chloroplasts per cell section, since they were not induced by P(i) fertilization. Photosynthetic activity per leaf area remained the same regardless of type of treatment. In conclusion, the increase in growth of mycorrhized and P(i)-fertilized Medicago truncatula plants is linked to an increase in the surface for sunlight capture, hence increasing their photosynthetic production, rather than to an increase in the photosynthetic activity per leaf area.

  2. Sunlight and Vitamin D: The Bone and Cancer Connections (invited paper)

    Energy Technology Data Exchange (ETDEWEB)

    Holick, M.F

    2000-07-01

    Vitamin D plays an essential role for calcium metabolism and bone health. It has been estimated that 90 to 95% of our vitamin D requirement comes from casual exposure to sunlight. There is a wide variety of factors that strongly influence the cutaneous production of vitamin D. These include melanin pigmentation, latitude, time of day, sunscreen use, and aging. There is an association with increased risk and mortality to breast, colon, and prostrate cancer. There is evidence that 25-hydroxyvitamin D, the major circulating form of vitamin D, is directly metabolised in prostate, breast, colon, and skin cells to its active form 1,25-dihydroxyvitamin D. 1,25-Dihydroxyvitamin D{sub 3} has the capacity to regulate cell proliferation and differentiation. Therefore, it may be that an increase in the cutaneous synthesis of vitamin D results in the increase in the production of 1,25(OH){sub 2}D in tissues not related to calcium metabolism that results in a decrease in malignancy. (author)

  3. Photocatalytic degradation of five sulfonylurea herbicides in aqueous semiconductor suspensions under natural sunlight.

    Science.gov (United States)

    Fenoll, José; Hellín, Pilar; Flores, Pilar; Martínez, Carmen María; Navarro, Simón

    2012-05-01

    In the present study, the photocatalytic degradation of five sulfonylurea herbicides (chlorsulfuron, flazasulfuron, nicosulfuron, sulfosulfuron and triasulfuron) has been investigated in aqueous suspensions of zinc oxide (ZnO), tungsten (VI) oxide (WO(3)), tin (IV) oxide (SnO(2)) and zinc sulfide (ZnS) at pilot plant scale under natural sunlight. Photocatalytic experiments, especially those involving ZnO photocatalysis, showed that the addition of semiconductors in tandem with the oxidant (Na(2)S(2)O(8)) strongly enhances the degradation rate of the herbicides in comparisons carried out with photolytic tests. The degradation of the herbicides follows a first order kinetics according to the Langmuir-Hinshelwood model. In our conditions, the amount of time required for 50% of the initial pesticide concentration to dissipate (t(½)) ranged from 8 to 27 min (t(30W)=0.3-1.2 min) for sulfosulfuron and chlorsulfuron, respectively in the ZnO/Na(2)S(2)O(8) system. None of the studied herbicides was found after 120 min of illumination (except chlorsulfuron, 0.2 μg L(-1)).

  4. Nanostructured photosystems for the generation of electricity and fuels from sunlight

    Science.gov (United States)

    Grätzel, Michael

    2013-03-01

    Learning from the concepts used by green plants photosynthesis, we have developed nanostructured systems affording efficient solar light harvesting and conversion to electricity and fuels. Solar cells using dyes or semiconducting nanoparticles as light harvesters supported by mesoscopic oxide films have emerged as credible contenders to conventional p-n junction photovoltaic devices. Separating light absorption from charge carrier transport dye sensitized mesoscopic solar cells (DSCs) were the first to use a three-dimensional nanocrystalline junction for solar electricity production. The standard AM 1.5 solar to electric power conversion efficiency (PCE) has reached 12.9% for laboratory cells and 9.9% for PV modules. Even higher efficiencies are attained under ambient and indoor light conditions. These features along with excellent long-term stability have fostered first commercial applications, the industrial production of DSC's attaining presently the MW/year scale. Very exciting results have recently been obtained with perovskites and quantum dot particles as light harvesters in mesoscopic solar cells. Striking advances in the direct generation of fuels such as hydrogen from water and sunlight have been achieved by the judicious design of photosystems composed of nanostructured Fe2O3 or Cu2O films.

  5. Evidence for Alteration in Chemical and Physical Properties of Water and Modulation of its Biological Functions by Sunlight Transmitted through Color Ranges of the Visible Spectrum-A Novel Study

    Directory of Open Access Journals (Sweden)

    M. Rajeswara Rao

    2005-08-01

    Full Text Available We investigated the changes in the properties of water when exposed to sunlight for 40 days. We hypothesize and prove that solar irradiation to water entraps electromagnetic radiation as potential energy, which becomes kinetic energy in various systems. It is postulated that photochemically-induced energy transfers, associated with individual spectral emission of visible spectrum of solar light, exert diverse influences on biological systems. Bottles of distilled water, individually wrapped in spectral-colored cellophane were exposed to sunlight and compared to an unwrapped bottle to determine chemical and physical changes as well as modifications of biological properties. Each bottle of water was named according to the color of cellophane paper with letter E (stands for exposed as a prefix with (E-violet, E-indigo, E-blue, E-green, E-yellow, E-orange, and Ered. E-control (without wrap was exposed to polychromatic sunlight. This study addresses two main issues viz., the chemical and physical changes in E-water and its effect on biological activities. Chemical and physical composition analysis using inductively coupled plasma atomic emission spectrometry; physical conductance by a Wheatstone Bridge type conductivity meter; osmolarity by a vapor pressure osmometer; and, salt solubility profile of 10% sodium bicarbonate were determined. Furthermore, testing the effect of E-waters on human lymphocyte proliferation, mosquito larvae hatching and seed germination determined the functional role of solar radiation through specific spectrum/s of visible light on various biological processes. We found that water exposed to visible spectral emissions of sunlight had an altered elemental composition, electrical conductance, osmolarity and salt-solubility, as well as differences in bio-modulatory effects. A gradual increase in leaching of Boron from Eviolet to E-red was noted. E-indigo showed maximal increase in electrical conductance and maximal salt

  6. Effect of Cluster Coulomb Fields on Electron Acceleration in Laser-Cluster Interaction

    Institute of Scientific and Technical Information of China (English)

    CANG Yu; DONG Quan-Li; WU Hui-Chun; SHENG Zheng-Ming; YU Wei; ZHANG Jie

    2004-01-01

    @@ Single particle simulations are used to investigate electron acceleration in the laser-clusterinteraction, taking into account the Coulomb fields around individual clusters. These Coulomb fields are induced from the cluster cores with positive charge when electrons escape from the cluster cores through ponderomotive push from the laser field. These Coulomb fields enable some stripped electrons to be stochastically in phases with the laser fields so that they can gain net energy from the laser efficiently. In this heating mechanism, circularly polarized lasers, larger cluster size and higher cluster densities make the acceleration more efficient.

  7. Cluster headache

    Directory of Open Access Journals (Sweden)

    Ducros Anne

    2008-07-01

    Full Text Available Abstract Cluster headache (CH is a primary headache disease characterized by recurrent short-lasting attacks (15 to 180 minutes of excruciating unilateral periorbital pain accompanied by ipsilateral autonomic signs (lacrimation, nasal congestion, ptosis, miosis, lid edema, redness of the eye. It affects young adults, predominantly males. Prevalence is estimated at 0.5–1.0/1,000. CH has a circannual and circadian periodicity, attacks being clustered (hence the name in bouts that can occur during specific months of the year. Alcohol is the only dietary trigger of CH, strong odors (mainly solvents and cigarette smoke and napping may also trigger CH attacks. During bouts, attacks may happen at precise hours, especially during the night. During the attacks, patients tend to be restless. CH may be episodic or chronic, depending on the presence of remission periods. CH is associated with trigeminovascular activation and neuroendocrine and vegetative disturbances, however, the precise cautive mechanisms remain unknown. Involvement of the hypothalamus (a structure regulating endocrine function and sleep-wake rhythms has been confirmed, explaining, at least in part, the cyclic aspects of CH. The disease is familial in about 10% of cases. Genetic factors play a role in CH susceptibility, and a causative role has been suggested for the hypocretin receptor gene. Diagnosis is clinical. Differential diagnoses include other primary headache diseases such as migraine, paroxysmal hemicrania and SUNCT syndrome. At present, there is no curative treatment. There are efficient treatments to shorten the painful attacks (acute treatments and to reduce the number of daily attacks (prophylactic treatments. Acute treatment is based on subcutaneous administration of sumatriptan and high-flow oxygen. Verapamil, lithium, methysergide, prednisone, greater occipital nerve blocks and topiramate may be used for prophylaxis. In refractory cases, deep-brain stimulation of the

  8. Gene Cluster Statistics with Gene Families

    Science.gov (United States)

    Durand, Dannie

    2009-01-01

    Identifying genomic regions that descended from a common ancestor is important for understanding the function and evolution of genomes. In distantly related genomes, clusters of homologous gene pairs are evidence of candidate homologous regions. Demonstrating the statistical significance of such “gene clusters” is an essential component of comparative genomic analyses. However, currently there are no practical statistical tests for gene clusters that model the influence of the number of homologs in each gene family on cluster significance. In this work, we demonstrate empirically that failure to incorporate gene family size in gene cluster statistics results in overestimation of significance, leading to incorrect conclusions. We further present novel analytical methods for estimating gene cluster significance that take gene family size into account. Our methods do not require complete genome data and are suitable for testing individual clusters found in local regions, such as contigs in an unfinished assembly. We consider pairs of regions drawn from the same genome (paralogous clusters), as well as regions drawn from two different genomes (orthologous clusters). Determining cluster significance under general models of gene family size is computationally intractable. By assuming that all gene families are of equal size, we obtain analytical expressions that allow fast approximation of cluster probabilities. We evaluate the accuracy of this approximation by comparing the resulting gene cluster probabilities with cluster probabilities obtained by simulating a realistic, power-law distributed model of gene family size, with parameters inferred from genomic data. Surprisingly, despite the simplicity of the underlying assumption, our method accurately approximates the true cluster probabilities. It slightly overestimates these probabilities, yielding a conservative test. We present additional simulation results indicating the best choice of parameter values for data

  9. Porous graphitic carbon nitride synthesized via direct polymerization of urea for efficient sunlight-driven photocatalytic hydrogen production.

    Science.gov (United States)

    Zhang, Yuewei; Liu, Jinghai; Wu, Guan; Chen, Wei

    2012-09-07

    Energy captured directly from sunlight provides an attractive approach towards fulfilling the need for green energy resources on the terawatt scale with minimal environmental impact. Collecting and storing solar energy into fuel through photocatalyzed water splitting to generate hydrogen in a cost-effective way is desirable. To achieve this goal, low cost and environmentally benign urea was used to synthesize the metal-free photocatalyst graphitic carbon nitride (g-C₃N₄). A porous structure is achieved via one-step polymerization of the single precursor. The porous structure with increased BET surface area and pore volume shows a much higher hydrogen production rate under simulated sunlight irradiation than thiourea-derived and dicyanamide-derived g-C₃N₄. The presence of an oxygen atom is presumed to play a key role in adjusting the textural properties. Further improvement of the photocatalytic function can be expected with after-treatment due to its rich chemistry in functionalization.

  10. Plant uptake-assisted round-the-clock photocatalysis for complete purification of aquaculture wastewater using sunlight.

    Science.gov (United States)

    Bian, Zhenfeng; Cao, Fenglei; Zhu, Jian; Li, Hexing

    2015-02-17

    A novel reactor equipped with solar batteries, Bi2O3/TiO2 film photocatalyst, and celery plant was designed and used for purification of aquaculture wastewater. The Bi2O3/TiO2 film photocatalyst started photocatalytic degradation of organonitrogen compounds under irradiation of sunlight. Meanwhile, the solar batteries absorbed and converted excess sunlight into electric energy and then started UV lamps at night, leading to round-the-clock photocatalysis. Subsequently, the inorganic nitrogen species including NH4(+), NO2(-), and NO3(-) resulting from photocatalytic degradation of the organonitrogen compounds could subsequently be uptaken by the celery plant as the fertilizer to reduce the secondary pollution. It was found that, after 24 h circulation, both organonitrogen compounds and NO2(-) species were completely removed, while NH4(+) and NO3(-) contents also decreased by 30% and 50%, respectively. The reactor could be used repetitively, showing a good potential in practical application.

  11. Relativistic Binaries in Globular Clusters

    Directory of Open Access Journals (Sweden)

    Matthew J. Benacquista

    2013-03-01

    Full Text Available Galactic globular clusters are old, dense star systems typically containing 10^4 – 10^6 stars. As an old population of stars, globular clusters contain many collapsed and degenerate objects. As a dense population of stars, globular clusters are the scene of many interesting close dynamical interactions between stars. These dynamical interactions can alter the evolution of individual stars and can produce tight binary systems containing one or two compact objects. In this review, we discuss theoretical models of globular cluster evolution and binary evolution, techniques for simulating this evolution that leads to relativistic binaries, and current and possible future observational evidence for this population. Our discussion of globular cluster evolution will focus on the processes that boost the production of tight binary systems and the subsequent interaction of these binaries that can alter the properties of both bodies and can lead to exotic objects. Direct N-body integrations and Fokker–Planck simulations of the evolution of globular clusters that incorporate tidal interactions and lead to predictions of relativistic binary populations are also discussed. We discuss the current observational evidence for cataclysmic variables, millisecond pulsars, and low-mass X-ray binaries as well as possible future detection of relativistic binaries with gravitational radiation.

  12. Identification of Urban Leprosy Clusters

    Directory of Open Access Journals (Sweden)

    José Antonio Armani Paschoal

    2013-01-01

    Full Text Available Overpopulation of urban areas results from constant migrations that cause disordered urban growth, constituting clusters defined as sets of people or activities concentrated in relatively small physical spaces that often involve precarious conditions. Aim. Using residential grouping, the aim was to identify possible clusters of individuals in São José do Rio Preto, Sao Paulo, Brazil, who have or have had leprosy. Methods. A population-based, descriptive, ecological study using the MapInfo and CrimeStat techniques, geoprocessing, and space-time analysis evaluated the location of 425 people treated for leprosy between 1998 and 2010. Clusters were defined as concentrations of at least 8 people with leprosy; a distance of up to 300 meters between residences was adopted. Additionally, the year of starting treatment and the clinical forms of the disease were analyzed. Results. Ninety-eight (23.1% of 425 geocoded cases were located within one of ten clusters identified in this study, and 129 cases (30.3% were in the region of a second-order cluster, an area considered of high risk for the disease. Conclusion. This study identified ten clusters of leprosy cases in the city and identified an area of high risk for the appearance of new cases of the disease.

  13. Autophagy selectivity through receptor clustering

    Science.gov (United States)

    Rutenberg, Andrew; Brown, Aidan

    Substrate selectivity in autophagy requires an all-or-none cellular response. We focus on peroxisomes, for which autophagy receptor proteins NBR1 and p62 are well characterized. Using computational models, we explore the hypothesis that physical clustering of autophagy receptor proteins on the peroxisome surface provides an appropriate all-or-none response. We find that larger peroxisomes nucleate NBR1 clusters first, and lose them due to competitive coarsening last, resulting in significant size-selectivity. We then consider a secondary hypothesis that p62 inhibits NBR1 cluster formation. We find that p62 inhibition enhances size-selectivity enough that, even if there is no change of the pexophagy rate, the volume of remaining peroxisomes can significantly decrease. We find that enhanced ubiquitin levels suppress size-selectivity, and that this effect is more pronounced for individual peroxisomes. Sufficient ubiquitin allows receptor clusters to form on even the smallest peroxisomes. We conclude that NBR1 cluster formation provides a viable physical mechanism for all-or-none substrate selectivity in pexophagy. We predict that cluster formation is associated with significant size-selectivity. Now at Simon Fraser University.

  14. Interstellar extinction by fractal polycrystalline graphite clusters?

    CERN Document Server

    Andersen, A C; Pustovit, V N; Niklasson, G A

    2001-01-01

    Certain dust particles in space are expected to appear as clusters of individual grains. The morphology of these clusters could be fractal or compact. To determine how these structural features would affect the interpretation of the observed interstellar extinction peak at $\\sim 4.6~\\mu$m, we have calculated the extinction by compact and fractal polycrystalline graphite clusters consisting of touching identical spheres. We compare three general methods for computing the extinction of the clusters, namely, a rigorous solution and two different discrete-dipole approximation methods.

  15. Individualizing Medicare.

    Science.gov (United States)

    Chollet, D J

    1999-05-01

    Despite the enactment of significant changes to the Medicare program in 1997, Medicare's Hospital Insurance trust fund is projected to be exhausted just as the baby boom enters retirement. To address Medicare's financial difficulties, a number of reform proposals have been offered, including several to individualize Medicare financing and benefits. These proposals would attempt to increase Medicare revenues and reduce Medicare expenditures by having individuals bear risk--investment market risk before retirement and insurance market risk after retirement. Many fundamental aspects of these proposals have yet to be worked out, including how to guarantee a baseline level of saving for health insurance after retirement, how retirees might finance unanticipated health insurance price increases after retirement, the potential implications for Medicaid of inadequate individual saving, and whether the administrative cost of making the system fair and adequate ultimately would eliminate any rate-of-return advantages from allowing workers to invest their Medicare contributions in corporate stocks and bonds.

  16. Partitional clustering algorithms

    CERN Document Server

    2015-01-01

    This book summarizes the state-of-the-art in partitional clustering. Clustering, the unsupervised classification of patterns into groups, is one of the most important tasks in exploratory data analysis. Primary goals of clustering include gaining insight into, classifying, and compressing data. Clustering has a long and rich history that spans a variety of scientific disciplines including anthropology, biology, medicine, psychology, statistics, mathematics, engineering, and computer science. As a result, numerous clustering algorithms have been proposed since the early 1950s. Among these algorithms, partitional (nonhierarchical) ones have found many applications, especially in engineering and computer science. This book provides coverage of consensus clustering, constrained clustering, large scale and/or high dimensional clustering, cluster validity, cluster visualization, and applications of clustering. Examines clustering as it applies to large and/or high-dimensional data sets commonly encountered in reali...

  17. Clustering and Community Detection with Imbalanced Clusters

    OpenAIRE

    Aksoylar, Cem; Qian, Jing; Saligrama, Venkatesh

    2016-01-01

    Spectral clustering methods which are frequently used in clustering and community detection applications are sensitive to the specific graph constructions particularly when imbalanced clusters are present. We show that ratio cut (RCut) or normalized cut (NCut) objectives are not tailored to imbalanced cluster sizes since they tend to emphasize cut sizes over cut values. We propose a graph partitioning problem that seeks minimum cut partitions under minimum size constraints on partitions to de...

  18. Cellular and molecular mechanism of ofloxacin induced apoptotic cell death under ambient UV-A and sunlight exposure.

    Science.gov (United States)

    Dwivedi, A; Mujtaba, S F; Yadav, N; Kushwaha, H N; Amar, S K; Singh, S K; Pant, M C; Ray, R S

    2014-03-01

    Ofloxacin (OFLX) is a racemic mixture of levofloxacin which revealed phototoxicity in patients exposed with sunlight after medication. Here, we have been addressed the possible cellular and molecular mechanisms of OFLX induced apoptosis under ambient UV-A and sunlight exposure using HaCaT cell line as a model. The results showed that Photodegradation and three photo-products formation of OFLX by LC-MS/MS under ambient intensities of UV-A (1.5 and 2.2 mW/cm(2)) and sunlight. OFLX produced (1)O2, O2(.-), and OH radicals via type-II- and type-I-dependent reaction mechanism, which corroborated by its specific quenchers. 2'-dGua degradation in photochemical and % tail DNA formation in cell line using comet test advocated the genotoxic potential of OFLX. Photocytotoxic assays (MTT and NRU) revealed the considerable decline in cell viability by OFLX. OFLX triggered apoptosis, proved by cell cycle, Annexin V/PI double staining along with acridine orange (AO)/ethidium bromide (EB), and Hoechst staining as well as caspase-3 activity by colorimetric assay. OFLX induced lysosomal disruption and mitochondrial membrane destabilization confirmed through fluorescence staining with AO/JC-1. OFLX significantly upregulated the expression of p21 and bax genes. In conclusion, the study revealed that photosensitized OFLX induced apoptosis via ROS-mediated DNA damage, destabilization of lysosomal and mitochondrial membrane, and upregulation of p21, bax, and caspase-3 genes.

  19. Photocatalytic degradation of Orange G on nitrogen-doped TiO2 catalysts under visible light and sunlight irradiation.

    Science.gov (United States)

    Sun, Jianhui; Qiao, Liping; Sun, Shengpeng; Wang, Guoliang

    2008-06-30

    In this paper, the degradation of an azo dye Orange G (OG) on nitrogen-doped TiO2 photocatalysts has been investigated under visible light and sunlight irradiation. Under visible light irradiation, the doped TiO2 nanocatalysts demonstrated higher activity than the commercial Dugussa P25 TiO2, allowing more efficient utilization of solar light, while under sunlight, P25 showed higher photocatalytic activity. According to the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectra analyses, it was found that both the nanosized anatase structure and the appearance of new absorption band in the visible region caused by nitrogen doping were responsible for the significant enhancement of OG degradation under visible light. In addition, the photosensitized oxidation mechanism originated from OG itself was also considered contributing to the higher visible-light-induced degradation efficiency. The effect of the initial pH of the solution and the dosage of hydrogen peroxide under different light sources was also investigated. Under visible light and sunlight, the optimal solution pH was both 2.0, while the optimal dosage of H2O2 was 5.0 and 15.0 mmol/l, respectively.

  20. Sunlight inactivation of viruses in open-water unit process treatment wetlands: modeling endogenous and exogenous inactivation rates.

    Science.gov (United States)

    Silverman, Andrea I; Nguyen, Mi T; Schilling, Iris E; Wenk, Jannis; Nelson, Kara L

    2015-03-03

    Sunlight inactivation is an important mode of disinfection for viruses in surface waters. In constructed wetlands, for example, open-water cells can be used to promote sunlight disinfection and remove pathogenic viruses from wastewater. To aid in the design of these systems, we developed predictive models of virus attenuation that account for endogenous and exogenous sunlight-mediated inactivation mechanisms. Inactivation rate models were developed for two viruses, MS2 and poliovirus type 3; laboratory- and field-scale experiments were conducted to evaluate the models' ability to estimate inactivation rates in a pilot-scale, open-water, unit-process wetland cell. Endogenous inactivation rates were modeled using either photoaction spectra or total, incident UVB irradiance. Exogenous inactivation rates were modeled on the basis of virus susceptibilities to singlet oxygen. Results from both laboratory- and field-scale experiments showed good agreement between measured and modeled inactivation rates. The modeling approach presented here can be applied to any sunlit surface water and utilizes easily measured inputs such as depth, solar irradiance, water matrix absorbance, singlet oxygen concentration, and the virus-specific apparent second-order rate constant with singlet oxygen (k2). Interestingly, the MS2 k2 in the open-water wetland was found to be significantly larger than k2 observed in other waters in previous studies. Examples of how the model can be used to design and optimize natural treatment systems for virus inactivation are provided.

  1. Decoloring Methyl Orange under Sunlight by a Photocatalytic Membrane Reactor Based on ZnO Nanoparticles and Polypropylene Macroporous Membrane

    Directory of Open Access Journals (Sweden)

    Bing Hu

    2013-01-01

    Full Text Available Decoloring methyl orange (MeOr under sunlight was conducted in a photocatalytic membrane reactor (PMR. Zinc oxide nanoparticles (ZnO NPs were suspended in the solution or immobilized on the membrane. The membrane was modified by grafting 2-hydroxyethyl methacrylate (HEMA to enhance the adsorption of ZnO NPs on the hydrophobic membrane surface and improve the membrane permeability. The results show that the water fluxes through the modified membranes are higher than that through the unmodified membrane. After introducing ZnO NPs to the membrane, the water fluxes still rise with the immobilization degree of ZnO NPs. For the PMR with ZnO NPs in suspension, the photocatalytic decoloration percent (PDP was over 98.2% after 40 min under sunlight. For the PMR with ZnO NPs immobilized on the membrane, the max of PDP was 74.3% after 6 h under sunlight, and maintained at 72% after repeated uses for five times. These results demonstrate that photocatalytic membrane reactor (PMR based on ZnO NPs and polypropylene macroporous membrane(PPMM could be applied in decoloring dyes.

  2. IntroductionThe Cluster mission

    Directory of Open Access Journals (Sweden)

    M. Fehringer

    Full Text Available The Cluster mission, ESA’s first cornerstone project, together with the SOHO mission, dating back to the first proposals in 1982, was finally launched in the summer of 2000. On 16 July and 9 August, respectively, two Russian Soyuz rockets blasted off from the Russian cosmodrome in Baikonour to deliver two Cluster spacecraft, each into their proper orbit. By the end of August 2000, the four Cluster satellites had reached their final tetrahedral constellation. The commissioning of 44 instruments, both individually and as an ensemble of complementary tools, was completed five months later to ensure the optimal use of their combined observational potential. On 1 February 2001, the mission was declared operational. The main goal of the Cluster mission is to study the small-scale plasma structures in three dimensions in key plasma regions, such as the solar wind, bow shock, magnetopause, polar cusps, magnetotail and the auroral zones. With its unique capabilities of three-dimensional spatial resolution, Cluster plays a major role in the International Solar Terrestrial Program (ISTP, where Cluster and the Solar and Heliospheric Observatory (SOHO are the European contributions. Cluster’s payload consists of state-of-the-art plasma instrumentation to measure electric and magnetic fields from the quasi-static up to high frequencies, and electron and ion distribution functions from energies of nearly 0 eV to a few MeV. The science operations are coordinated by the Joint Science Operations Centre (JSOC, at the Rutherford Appleton Laboratory (UK, and implemented by the European Space Operations Centre (ESOC, in Darmstadt, Germany. A network of eight national data centres has been set up for raw data processing, for the production of physical parameters, and their distribution to end users all over the world. The latest information on the Cluster mission can be found at http://sci.esa.int/cluster/.

  3. Measurements of pulse rate using long-range imaging photoplethysmography and sunlight illumination outdoors

    Science.gov (United States)

    Blackford, Ethan B.; Estepp, Justin R.

    2017-02-01

    Imaging photoplethysmography, a method using imagers to record absorption variations caused by microvascular blood volume pulsations, shows promise as a non-contact cardiovascular sensing technology. The first long-range imaging photoplethysmography measurements at distances of 25, 50, and 100 meters from the participant was recently demonstrated. Degraded signal quality was observed with increasing imager-to-subject distances. The degradation in signal quality was hypothesized to be largely attributable to inadequate light return to the image sensor with increasing lens focal length. To test this hypothesis, a follow-up evaluation with 27 participants was conducted outdoors with natural sunlight illumination resulting in 5-33 times the illumination intensity. Video was recorded from cameras equipped with ultra-telephoto lenses and positioned at distances of 25, 50, 100, and 150 meters. The brighter illumination allowed high-definition video recordings at increased frame rates of 60fps, shorter exposure times, and lower ISO settings, leading to higher quality image formation than the previous indoor evaluation. Results were compared to simultaneous reference measurements from electrocardiography. Compared to the previous indoor study, we observed lower overall error in pulse rate measurement with the same pattern of degradation in signal quality with respect to increasing distance. This effect was corroborated by the signal-to-noise ratio of the blood volume pulse signal which also showed decreasing quality with respect to increasing distance. Finally, a popular chrominance-based method was compared to a blind source separation approach; while comparable in measurement of signal-to-noise ratio, we observed higher overall error in pulse rate measurement using the chrominance method in this data.

  4. Sensitivity Studies for Space-based Measurements of Atmospheric Total Column Carbon Dioxide Using Reflected Sunlight

    Science.gov (United States)

    Mao, Jianping; Kawa, S. Randolph

    2003-01-01

    A series of sensitivity studies is carried out to explore the feasibility of space-based global carbon dioxide (CO2) measurements for global and regional carbon cycle studies. The detection method uses absorption of reflected sunlight in the CO2 vibration-rotation band at 1.58 micron. The sensitivities of the detected radiances are calculated using the line-by-line model (LBLRTM), implemented with the DISORT (Discrete Ordinates Radiative Transfer) model to include atmospheric scattering in this band. The results indicate that (a) the small (approx.1%) changes in CO2 near the Earth's surface are detectable in this CO2 band provided adequate sensor signal-to-noise ratio and spectral resolution are achievable; (b) the effects of other interfering constituents, such as water vapor, aerosols and cirrus clouds, on the radiance are significant but the overall effects of the modification of light path length on total back-to-space radiance sensitivity to CO2 change are minor for general cases, which means that generally the total column CO2 can be derived in high precision from the ratio of the on-line center to off-line radiances; (c) together with CO2 gas absorption aerosol/cirrus cloud layer has differential scattering which may result in the modification of on-line to off-line radiance ratio which could lead a large bias in the total column CO2 retrieval. Approaches to correct such bias need further investigation. (d) CO2 retrieval requires good knowledge of the atmospheric temperature profile, e.g. approximately 1K RMS error in layer temperature, which is achievable from new atmospheric sounders in the near future; (e) the atmospheric path length, over which the CO2 absorption occurs, should be known in order to correctly interpret horizontal gradients of CO2 from the total column CO2 measurement; thus an additional sensor for surface pressure measurement needs to be attached for a complete measurement package.

  5. Degradation of DEET and Caffeine under UV/Chlorine and Simulated Sunlight/Chlorine Conditions.

    Science.gov (United States)

    Sun, Peizhe; Lee, Wan-Ning; Zhang, Ruochun; Huang, Ching-Hua

    2016-12-20

    Photoactivation of aqueous chlorine could promote degradation of chlorine-resistant and photochemically stable chemicals accumulated in swimming pools. This study investigated the degradation of two such chemicals, N,N-diethyl-3-methylbenzamide (DEET) and caffeine, by low pressure ultraviolet (UV) light and simulated sunlight (SS) activated free chlorine (FC) in different water matrices. Both DEET and caffeine were rapidly degraded by UV/FC and SS/FC but exhibited different kinetic behaviors. The degradation of DEET followed pseudo-first-order kinetics, whereas the degradation of caffeine accelerated with reaction. Mechanistic study revealed that, under UV/FC, ·OH and Cl· were responsible for degradation of DEET, whereas ClO· related reactive species (ClOrrs), generated by the reaction between FC and ·OH/Cl·, played a major role in addition to ·OH and Cl· in degrading caffeine. Reaction rate constants of DEET and caffeine with the respective radical species were estimated. The imidazole moiety of caffeine was critical for the special reactivity with ClOrrs. Water matrix such as pH had a stronger impact on the UV/FC process than the SS/FC process. In saltwater matrix under UV/FC and SS/FC, the degradation of DEET was significantly inhibited, but the degradation of caffeine was much faster than that in nonsalty solutions. The interaction between Br(-) and Cl(-) may play an important role in the degradation of caffeine by UV/FC in saltwater. Reaction product analysis showed similar product patterns by UV/FC and SS/FC and minimal formation of chlorinated intermediates and disinfection byproducts.

  6. A practical demonstration of water disinfection using TiO2 films and sunlight.

    Science.gov (United States)

    Gelover, Silvia; Gómez, Luis A; Reyes, Karina; Teresa Leal, Ma

    2006-10-01

    The scope of this study is the assessment of the efficiency of solar disinfection by heterogeneous photocatalysis with sol-gel immobilized (titanium dioxide) TiO2 films over glass cylinders. The solar disinfection process known as SODIS was considered as a reference. Spring water naturally polluted with coliform bacteria was exposed to sunlight in plastic bottles with and without TiO2 over simple solar collectors and the disinfection effectiveness was measured. Total and fecal coliforms quantification was performed by means of the chromogenic substrate method in order to obtain the efficiency of each disinfection treatment. The disinfection with TiO2 was more efficient than the SODIS process, inactivating total coliforms as well as fecal coliforms. On a sunny day (more than 1000 W m(-2) irradiance), it took the disinfection with immobilized TiO2 15 min of irradiation to inactivate the fecal coliforms to make them undetectable. For inactivation of total coliforms, 30 min was required, so that in less than half the time it takes SODIS, the treated water complies with the microbial standards for drinking water in Mexico. Another important part of this study has been to determine the bacterial regrowth in water after the disinfection processes were tested. After SODIS, bacterial regrowth of coliforms was observed. In contrast, when using the TiO2 catalyst, coliforms regrowth was not detected, neither for total nor for fecal coliforms. The disinfection process using TiO2 kept treated water free of coliforms at least for seven days after sun irradiation. This demonstration opens the possibility of application of this simple method in rural areas of developing countries.

  7. Antiradical capacity and polyphenol composition of asparagus spears varieties cultivated under diff erent sunlight conditions

    Directory of Open Access Journals (Sweden)

    Bartosz Kulczyński

    2016-09-01

    sunlight and variety. Asparagus can provide a valuable source of phenolic compounds in the human diet.

  8. Numerical simulation of primary cluster formation in silane plasmas

    CERN Document Server

    Gupta, N; Kroesen, G

    2003-01-01

    The usage of low-cost silicon-based solar cells is limited by their tendency to degrade on prolonged exposure to sunlight. Current research has indicated that the inclusion of nano-particles in the plasma-deposited film enhances its efficiency considerably. It is therefore essential to identify the plasma operating conditions such that nano-particles are formed and deposited in the film. The early stages of cluster formation, nucleation and coagulation are still open to experimental and theoretical investigation. In this paper, a simulation of the first stage of particle formation in capacitively coupled radio-frequency discharges in SiH sub 4 is attempted. A molecular dynamics based model has been set up to simulate one of the principal reaction pathways in cluster formation. This simulation model appears to produce valid and meaningful trends. Further studies are planned to explore the effect of other parameters and alternate pathways.

  9. Numerical simulation of primary cluster formation in silane plasmas

    Science.gov (United States)

    Gupta, Nandini; Stoffels, W. W.; Kroesen, G. M. W.

    2003-04-01

    The usage of low-cost silicon-based solar cells is limited by their tendency to degrade on prolonged exposure to sunlight. Current research has indicated that the inclusion of nano-particles in the plasma-deposited film enhances its efficiency considerably. It is therefore essential to identify the plasma operating conditions such that nano-particles are formed and deposited in the film. The early stages of cluster formation, nucleation and coagulation are still open to experimental and theoretical investigation. In this paper, a simulation of the first stage of particle formation in capacitively coupled radio-frequency discharges in SiH4 is attempted. A molecular dynamics based model has been set up to simulate one of the principal reaction pathways in cluster formation. This simulation model appears to produce valid and meaningful trends. Further studies are planned to explore the effect of other parameters and alternate pathways.

  10. Collective individualism

    DEFF Research Database (Denmark)

    Baarts, Charlotte

    2009-01-01

    Safety knowledge appears to be ‘a doing’. In construction work safety is practised in the complex interrelationship between the individual, pair and gang. Thus the aim is to explore the nature and scope of individualist and collectivist preferences pertaining to the practice of safety at a constr...

  11. Mass Distribution in Galaxy Cluster Cores

    CERN Document Server

    Hogan, M T; Pulido, F; Nulsen, P E J; Russell, H R; Vantyghem, A N; Edge, A C; Main, R A

    2016-01-01

    Many processes within galaxy clusters, such as those believed to govern the onset of thermally unstable cooling and AGN feedback, are dependent upon local dynamical timescales. However, accurately mapping the mass distribution within individual clusters is challenging, particularly towards cluster centres where the total mass budget has substantial radially-dependent contributions from the stellar, gas, and dark matter components. In this paper we use a small sample of galaxy clusters with deep Chandra observations and good ancillary tracers of their gravitating mass at both large and small radii to develop a method for determining mass profiles that span a wide radial range and extend down into the central galaxy. We also consider potential observational pitfalls in understanding cooling in hot cluster atmospheres, and find tentative evidence for a relationship between the radial extent of cooling X-ray gas and nebular H-alpha emission in cool core clusters. Amongst this small sample we find no support for t...

  12. Destruction of the galactic globular cluster system

    CERN Document Server

    Gnedin, O Y; Gnedin, Oleg Y; Ostriker, Jeremiah P

    1996-01-01

    We investigate the dynamical evolution of the Galactic Globular Cluster System in considerably greater detail than has been done hitherto, finding that destruction rates are significantly larger than given by previous estimates. More than half of the present clusters (52%-58% for the OC galactic model, and 75%-86% for the BSS model) will be destroyed in the next Hubble time. For the evolution of individual clusters we use a Fokker-Planck code including two-body relaxation, tidal truncation of clusters, compressive gravitational shocks while clusters pass through the Galactic disk, and tidal shocks due to passage close to the bulge. Gravitational shocks are treated comprehensively, using a recent result by Kundic & Ostriker (1995) that the shock-induced relaxation term, driving an additional dispersion of energies, is generally more important than the usual energy shift term. We discuss some implications for a past history of the Globular Cluster System, and the initial distribution of the destruction time...

  13. Serum 25-hydroxyvitamin-D responses to multiple UV exposures from solaria: inferences for exposure to sunlight.

    Science.gov (United States)

    McKenzie, Richard; Scragg, Robert; Liley, Ben; Johnston, Paul; Wishart, John; Stewart, Alistair; Prematunga, Roshani

    2012-07-01

    We investigate the relationship between blood serum 25-hydroxyvitamin D (25(OH)D) and UV exposure from two artificial sources. We then use the results to test the validity of the action spectrum for vitamin D production, and to infer the production from summer and winter sunlight. The results are based on a two-arm randomised clinical trial of biweekly UV exposure for 12 weeks using two different types of dermatological booths: one emitting primarily UV-A radiation, and the other emitting primarily UV-B radiation (booth A and booth B respectively). In terms of the vitamin D production per unit erythema, one of the booths mimics summer noon sunlight, while the other mimics winter noon sunlight. Blood samples were taken before and after the exposures. For all participants, the phototherapy booth treatments arrested the usual wintertime decline in 25(OH)D, and for most the treatments from either booth resulted in significant increases. The increases were highly non-linear and there was a high degree of variability in 25(OH)D and its response to UV from person to person. By the end of the 12 week period, the mean increase was >30 nmol l(-1) from a cumulative exposure of 17 SED from the UV-A booth, and twice that for the UV-B booth for which the cumulative exposure was 268 SED. Assuming a logarithmic relationship between UV and vitamin D, the results for the two booths show no obvious inconsistency in the action spectrum for pre-vitamin D production. However, further measurements with similar exposures from each booth are required to confirm its validity. A model was developed to describe the increases in serum 25(OH)D resulting from the UV exposures, which differed markedly between the two booths. The deduced initial rate of increase of 25(OH)D was approximately 5 nmol l(-1) per SED. From the large increases in 25(OH)D from each booth, along with knowledge of the spectral distribution of sunlight and assuming the currently-accepted action spectrum for photo

  14. Factorial PD-Clustering

    CERN Document Server

    Tortora, Cristina; Summa, Mireille Gettler

    2011-01-01

    Factorial clustering methods have been developed in recent years thanks to the improving of computational power. These methods perform a linear transformation of data and a clustering on transformed data optimizing a common criterion. Factorial PD-clustering is based on Probabilistic Distance clustering (PD-clustering). PD-clustering is an iterative, distribution free, probabilistic, clustering method. Factorial PD-clustering make a linear transformation of original variables into a reduced number of orthogonal ones using a common criterion with PD-Clustering. It is demonstrated that Tucker 3 decomposition allows to obtain this transformation. Factorial PD-clustering makes alternatively a Tucker 3 decomposition and a PD-clustering on transformed data until convergence. This method could significantly improve the algorithm performance and allows to work with large dataset, to improve the stability and the robustness of the method.

  15. Possibilistic Exponential Fuzzy Clustering

    Institute of Scientific and Technical Information of China (English)

    Kiatichai Treerattanapitak; Chuleerat Jaruskulchai

    2013-01-01

    Generally,abnormal points (noise and outliers) cause cluster analysis to produce low accuracy especially in fuzzy clustering.These data not only stay in clusters but also deviate the centroids from their true positions.Traditional fuzzy clustering like Fuzzy C-Means (FCM) always assigns data to all clusters which is not reasonable in some circumstances.By reformulating objective function in exponential equation,the algorithm aggressively selects data into the clusters.However noisy data and outliers cannot be properly handled by clustering process therefore they are forced to be included in a cluster because of a general probabilistic constraint that the sum of the membership degrees across all clusters is one.In order to improve this weakness,possibilistic approach relaxes this condition to improve membership assignment.Nevertheless,possibilistic clustering algorithms generally suffer from coincident clusters because their membership equations ignore the distance to other clusters.Although there are some possibilistic clustering approaches that do not generate coincident clusters,most of them require the right combination of multiple parameters for the algorithms to work.In this paper,we theoretically study Possibilistic Exponential Fuzzy Clustering (PXFCM) that integrates possibilistic approach with exponential fuzzy clustering.PXFCM has only one parameter and not only partitions the data but also filters noisy data or detects them as outliers.The comprehensive experiments show that PXFCM produces high accuracy in both clustering results and outlier detection without generating coincident problems.

  16. Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera

    Science.gov (United States)

    Matus, José Tomás; Loyola, Rodrigo; Vega, Andrea; Peña-Neira, Alvaro; Bordeu, Edmundo; Arce-Johnson, Patricio; Alcalde, José Antonio

    2009-01-01

    Anthocyanins, flavan-3-ols, and flavonols are the three major classes of flavonoid compounds found in grape berry tissues. Several viticultural practices increase flavonoid content in the fruit, but the underlying genetic mechanisms responsible for these changes have not been completely deciphered. The impact of post-veraison sunlight exposure on anthocyanin and flavonol accumulation in grape berry skin and its relation to the expression of different transcriptional regulators known to be involved in flavonoid synthesis was studied. Treatments consisting of removing or moving aside the basal leaves which shade berry clusters were applied. Shading did not affect sugar accumulation or gene expression of HEXOSE TRANSPORTER 1, although in the leaf removal treatment, these events were retarded during the first weeks of ripening. Flavonols were the most drastically reduced flavonoids following shading and leaf removal treatments, related to the reduced expression of FLAVONOL SYNTHASE 4 and its putative transcriptional regulator MYB12. Anthocyanin accumulation and the expression of CHS2, LDOX, OMT, UFGT, MYBA1, and MYB5a genes were also affected. Other regulatory genes were less affected or not affected at all by these treatments. Non-transcriptional control mechanisms for flavonoid synthesis are also suggested, especially during the initial stages of ripening. Although berries from the leaf removal treatment received more light than shaded fruits, malvidin-3-glucoside and total flavonol content was reduced compared with the treatment without leaf removal. This work reveals that flavonol-related gene expression responds rapidly to field changes in light levels, as shown by the treatment in which shaded fruits were exposed to light in the late stages of ripening. Taken together, this study establishes MYB-specific responsiveness for the effect of sun exposure and sugar transport on flavonoid synthesis. PMID:19129169

  17. An integrated general practice and pharmacy-based intervention to promote the use of appropriate preventive medications among individuals at high cardiovascular disease risk: protocol for a cluster randomized controlled trial.

    Science.gov (United States)

    Hayek, Adina; Joshi, Rohina; Usherwood, Tim; Webster, Ruth; Kaur, Baldeep; Saini, Bandana; Armour, Carol; Krass, Ines; Laba, Tracey-Lea; Reid, Christopher; Shiel, Louise; Hespe, Charlotte; Hersch, Fred; Jan, Stephen; Lo, Serigne; Peiris, David; Rodgers, Anthony; Patel, Anushka

    2016-09-23

    Cardiovascular diseases (CVD) are responsible for significant morbidity, premature mortality, and economic burden. Despite established evidence that supports the use of preventive medications among patients at high CVD risk, treatment gaps remain. Building on prior evidence and a theoretical framework, a complex intervention has been designed to address these gaps among high-risk, under-treated patients in the Australian primary care setting. This intervention comprises a general practice quality improvement tool incorporating clinical decision support and audit/feedback capabilities; availability of a range of CVD polypills (fixed-dose combinations of two blood pressure lowering agents, a statin ± aspirin) for prescription when appropriate; and access to a pharmacy-based program to support long-term medication adherence and lifestyle modification. Following a systematic development process, the intervention will be evaluated in a pragmatic cluster randomized controlled trial including 70 general practices for a median period of 18 months. The 35 general practices in the intervention group will work with a nominated partner pharmacy, whereas those in the control group will provide usual care without access to the intervention tools. The primary outcome is the proportion of patients at high CVD risk who were inadequately treated at baseline who achieve target blood pressure (BP) and low-density lipoprotein cholesterol (LDL-C) levels at the study end. The outcomes will be analyzed using data from electronic medical records, utilizing a validated extraction tool. Detailed process and economic evaluations will also be performed. The study intends to establish evidence about an intervention that combines technological innovation with team collaboration between patients, pharmacists, and general practitioners (GPs) for CVD prevention. Australian New Zealand Clinical Trials Registry ACTRN12616000233426.

  18. Ultraviolet Sunlight Exposure During Adolescence and Adulthood and Breast Cancer Risk: A Population-based Case-Control Study Among Ontario Women

    National Research Council Canada - National Science Library

    Anderson, Laura N; Cotterchio, Michelle; Kirsh, Victoria A; Knight, Julia A

    2011-01-01

    .... The associations among ultraviolet radiation from sunlight, factors related to cutaneous vitamin D production, and breast cancer risk were evaluated in a population-based case-control study conducted...

  19. Synergy of the Combination of Titanate Nanotubes with Titania Nanoparticles for the Photocatalytic Hydrogen Generation from Water-Methanol Mixture Using Simulated Sunlight

    Directory of Open Access Journals (Sweden)

    Marco Serra

    2014-01-01

    Full Text Available Alkali digestion of titanium nanoparticles leads, after neutralization, to the formation of titanate nanotubes with long aspect ratio. One salient change in the formation of titanate nanotubes is the observation of an extended visible absorption band up to 550 nm, responsible for their brown colour. Combination of titanate nanotubes with commercial titanium dioxide nanoparticles, either Evonik P25 or Millennium PC500, results in an enhanced photocatalytic activity for hydrogen generation from water-methanol mixtures. This synergy between the two titanium semiconductors has an optimum for a certain proportion of the two components and is observed in both the absence and the presence of platinum or gold nanoparticles. The best efficiency under simulated sunlight irradiation was for a combination of 12 wt.% titanate nanotubes containing 0.32 wt.% platinum in 88 wt.% Millennium PC500, where a two-time increase in the hydrogen generation is observed versus the activity of Millennium PC500 containing platinum. This synergy is proposed to derive from the interfacial electron transfer from titanate nanotubes undergoing photoexcitation at wavelengths in which Millennium PC500 does not absorb this form of titania nanoparticles. Our results illustrate how the combination of several titanium semiconductors can result in an enhancement efficiency with respect to their individual components.

  20. Effect of humic acids and sunlight on the cytotoxicity of engineered zinc oxide and titanium dioxide nanoparticles to a river bacterial assemblage

    Institute of Scientific and Technical Information of China (English)

    Thabitha P.Dasari; Huey-Min Hwang

    2013-01-01

    The effect of a terrestrial humic acid (HA) and Suwannee River HA on the cytotoxicity of engineered zinc oxide nanoparticles (ZnONPs)and titanium dioxide nanoparticles (TiO2NPs) to natural aquatic bacterial assemblages was measured with spread plate counting.The effect of HA (10 and 40 ppm) on the cytotoxicity of ZnONPs and TiO2NPs was tested factorially in the presence and absence of natural sunlight (light irradiation (LI)).The experiment was of full factorial,completely randomized design and the results were analyzed using the General Linear Model in SAS analytical software.The method of least squares means was used to separate the means or combinations of means.We determined the mechanism of toxicity via measurements of oxidative stress and metal ions.The toxicity of ZnONPs and TiO2NPs to natural aquatic bacterial assemblages appears to be concentration dependent.Moreover,the cytotoxicity of ZnONPs and TiO2NPs appeared to be affected by HA concentration,the presence of sunlight irradiation,and the dynamic multiple interactions among these factors.With respect to light versus darkness in the control group,the data indicate that bacterial viability was inhibited more in the light exposure than in the darkness exposure.The same was true in the HA treatment groups.With respect to terrestrial versus Suwanee River HA for a given nanoparticle,in light versus darkness,bacterial viability was more inhibited in the light treatment groups containing the terrestrial HA than in those containing Suwanee River HA.Differences in the extent of reactive oxygen species formation,adsorption/binding of ZnONPs/TiO2NPs by HA,and the levels of free metal ions were speculated to account for the observed cytotoxicity.TEM images indicate the attachment and binding of the tested nanoparticles to natural bacterial assemblages.Besides the individual parameter,significant effects on bacterial viability count were also observed in the following combined treatments

  1. Structures of Mn clusters

    Indian Academy of Sciences (India)

    Tina M Briere; Marcel H F Sluiter; Vijay Kumar; Yoshiyuki Kawazoe

    2003-01-01

    The geometries of several Mn clusters in the size range Mn13–Mn23 are studied via the generalized gradient approximation to density functional theory. For the 13- and 19-atom clusters, the icosahedral structures are found to be most stable, while for the 15-atom cluster, the bcc structure is more favoured. The clusters show ferrimagnetic spin configurations.

  2. Dissolution of Globular Clusters

    OpenAIRE

    Baumgardt, Holger

    2006-01-01

    Globular clusters are among the oldest objects in galaxies, and understanding the details of their formation and evolution can bring valuable insight into the early history of galaxies. This review summarises the current knowledge about the dissolution of star clusters and discusses the implications of star cluster dissolution for the evolution of the mass function of star cluster systems in galaxies.

  3. Clustering of correlated networks

    OpenAIRE

    Dorogovtsev, S. N.

    2003-01-01

    We obtain the clustering coefficient, the degree-dependent local clustering, and the mean clustering of networks with arbitrary correlations between the degrees of the nearest-neighbor vertices. The resulting formulas allow one to determine the nature of the clustering of a network.

  4. Dietary intakes of expeditioners during prolonged sunlight deprivation in polar enviroments do not support bone health

    Directory of Open Access Journals (Sweden)

    Sandra Iuliano

    2015-08-01

    Full Text Available Background: Early Antarctic expeditions were plagued by nutrient deficiencies, due to lack of fresh food and reliance on preserved foods. Modern Antarctic expeditioners also require provisions to be shipped in, but improved knowledge and storage options ensure foods are nutritionally sound. Despite this, nutritional imbalances are observed. Objectives: To determine the adequacy of dietary intake of Antarctic expeditioners, with reference to bone health. Design: Dietary intake was determined on 225 adults (mean age 42±11 years, 16% female during 12-month deployments at Australian Antarctic stations from 2004 to 2010, using weighed 3-day food records. Nutrient intake was analysed using FoodWorks. Foods were divided into the 5 food groups according to the Australian Guide to Healthy Eating. Results: Men consumed below the recommended levels [recommended daily intake (RDI/adequate intakes (AI] of calcium (79±42% of RDI, p<0.001, magnesium (83±34% of RDI, p<0.001, potassium (86±29% of AI, p<0.001 and fibre (75±30% of AI, p<0.001, and above the upper limit (UL for sodium (125±48% of UL p<0.001, whereas women consumed below the recommended levels of calcium (68±21% of RDI, p<0.001 and iron (73±37% of RDI, p<0.001. Vitamin D intake is not substantial (<150 IU/d. Men consumed more alcohol than women (18±24 g/d vs. 10±13 g/d, p<0.05, nearer the guideline of ≤20 g/d. Men and women consumed approximately 1 serving of dairy food per day, and 3 of 5 recommended vegetable servings. Discretionary foods were consumed in excess of recommended. Conclusions: Improving consumption of calcium-rich (dairy foods better supports bone health during sunlight deprivation. Increasing vegetable intake to recommended levels will increase fibre, potassium and magnesium intakes. The challenge is the logistics of providing these foods throughout the year.

  5. Contextualizing the Cluster

    DEFF Research Database (Denmark)

    Giacomin, Valeria

    This dissertation examines the case of the palm oil cluster in Malaysia and Indonesia, today one of the largest agricultural clusters in the world. My analysis focuses on the evolution of the cluster from the 1880s to the 1970s in order to understand how it helped these two countries to integrate......-researched topic in the cluster literature – the emergence of clusters, their governance and institutional change, and competition between rival cluster locations – through the case of the Southeast Asian palm oil cluster....

  6. Contextualizing the Cluster

    DEFF Research Database (Denmark)

    Giacomin, Valeria

    This dissertation examines the case of the palm oil cluster in Malaysia and Indonesia, today one of the largest agricultural clusters in the world. My analysis focuses on the evolution of the cluster from the 1880s to the 1970s in order to understand how it helped these two countries to integrate......-researched topic in the cluster literature – the emergence of clusters, their governance and institutional change, and competition between rival cluster locations – through the case of the Southeast Asian palm oil cluster....

  7. Coral: an integrated suite of visualizations for comparing clusterings

    Directory of Open Access Journals (Sweden)

    Filippova Darya

    2012-10-01

    Full Text Available Abstract Background Clustering has become a standard analysis for many types of biological data (e.g interaction networks, gene expression, metagenomic abundance. In practice, it is possible to obtain a large number of contradictory clusterings by varying which clustering algorithm is used, which data attributes are considered, how algorithmic parameters are set, and which near-optimal clusterings are chosen. It is a difficult task to sift though such a large collection of varied clusterings to determine which clustering features are affected by parameter settings or are artifacts of particular algorithms and which represent meaningful patterns. Knowing which items are often clustered together helps to improve our understanding of the underlying data and to increase our confidence about generated modules. Results We present Coral, an application for interactive exploration of large ensembles of clusterings. Coral makes all-to-all clustering comparison easy, supports exploration of individual clusterings, allows tracking modules across clusterings, and supports identification of core and peripheral items in modules. We discuss how each visual component in Coral tackles a specific question related to clustering comparison and provide examples of their use. We also show how Coral could be used to visually and quantitatively compare clusterings with a ground truth clustering. Conclusion As a case study, we compare clusterings of a recently published protein interaction network of Arabidopsis thaliana. We use several popular algorithms to generate the network’s clusterings. We find that the clusterings vary significantly and that few proteins are consistently co-clustered in all clusterings. This is evidence that several clusterings should typically be considered when evaluating modules of genes, proteins, or sequences, and Coral can be used to perform a comprehensive analysis of these clustering ensembles.

  8. Clustering in analytical chemistry.

    Science.gov (United States)

    Drab, Klaudia; Daszykowski, Michal

    2014-01-01

    Data clustering plays an important role in the exploratory analysis of analytical data, and the use of clustering methods has been acknowledged in different fields of science. In this paper, principles of data clustering are presented with a direct focus on clustering of analytical data. The role of the clustering process in the analytical workflow is underlined, and its potential impact on the analytical workflow is emphasized.

  9. Abnormal tyrosine metabolism in chronic cluster headache.

    Science.gov (United States)

    D'Andrea, Giovanni; Leone, Massimo; Bussone, Gennaro; Fiore, Paola Di; Bolner, Andrea; Aguggia, Marco; Saracco, Maria Gabriella; Perini, Francesco; Giordano, Giuseppe; Gucciardi, Antonina; Leon, Alberta

    2017-02-01

    Objective Episodic cluster headache is characterized by abnormalities in tyrosine metabolism (i.e. elevated levels of dopamine, tyramine, octopamine and synephrine and low levels of noradrenalin in plasma and platelets.) It is unknown, however, if such biochemical anomalies are present and/or constitute a predisposing factor in chronic cluster headache. To test this hypothesis, we measured the levels of dopamine and noradrenaline together with those of elusive amines, such as tyramine, octopamine and synephrine, in plasma of chronic cluster patients and control individuals. Methods Plasma levels of dopamine, noradrenaline and trace amines, including tyramine, octopamine and synephrine, were measured in a group of 23 chronic cluster headache patients (10 chronic cluster ab initio and 13 transformed from episodic cluster), and 16 control participants. Results The plasma levels of dopamine, noradrenaline and tyramine were several times higher in chronic cluster headache patients compared with controls. The levels of octopamine and synephrine were significantly lower in plasma of these patients with respect to control individuals. Conclusions These results suggest that anomalies in tyrosine metabolism play a role in the pathogenesis of chronic cluster headache and constitute a predisposing factor for the transformation of the episodic into a chronic form of this primary headache.

  10. Individual Consultations

    Directory of Open Access Journals (Sweden)

    Ian Walkinshaw

    2015-09-01

    Full Text Available Responding to calls for research into measurable English language outcomes from individual language support consultations at universities, this study investigated the effect of individual consultations (ICs on the academic writing skills and lexico-grammatical competence of students who speak English as an additional language (EAL. Attendance by 31 EAL students at ICs was recorded, and samples of their academic writing texts before and after a 9-month interval were compared. Participants’ academic writing skills were rated, and lexico-grammatical irregularities were quantified. No statistically significant positive shifts manifested, due to the relatively short research period and limited participant uptake, but there were encouraging predictors of future shifts given continued utilization of the service. First, although a Wilcoxon signed-rank test showed no association between attendance at ICs and shifts in academic writing ability, a Spearman’s rho calculation suggested a tentative relationship to positive pre–post shifts in three academic writing sub-skills: Task Fulfillment, Grammar, and Vocabulary. Second, instances of four common lexico-grammatical irregularities (subject/verb, wrong word, plural/singular, and punctuation declined at post-testing. Although only regular, sustained attendance would produce statistically significant shifts, there is a potential association between participants’ use of ICs and improved academic writing skills/lexico-grammatical competence.

  11. Multilevel Analysis Methods for Partially Nested Cluster Randomized Trials

    Science.gov (United States)

    Sanders, Elizabeth A.

    2011-01-01

    This paper explores multilevel modeling approaches for 2-group randomized experiments in which a treatment condition involving clusters of individuals is compared to a control condition involving only ungrouped individuals, otherwise known as partially nested cluster randomized designs (PNCRTs). Strategies for comparing groups from a PNCRT in the…

  12. Voting-based consensus clustering for combining multiple clusterings of chemical structures

    Directory of Open Access Journals (Sweden)

    Saeed Faisal

    2012-12-01

    Full Text Available Abstract Background Although many consensus clustering methods have been successfully used for combining multiple classifiers in many areas such as machine learning, applied statistics, pattern recognition and bioinformatics, few consensus clustering methods have been applied for combining multiple clusterings of chemical structures. It is known that any individual clustering method will not always give the best results for all types of applications. So, in this paper, three voting and graph-based consensus clusterings were used for combining multiple clusterings of chemical structures to enhance the ability of separating biologically active molecules from inactive ones in each cluster. Results The cumulative voting-based aggregation algorithm (CVAA, cluster-based similarity partitioning algorithm (CSPA and hyper-graph partitioning algorithm (HGPA were examined. The F-measure and Quality Partition Index method (QPI were used to evaluate the clusterings and the results were compared to the Ward’s clustering method. The MDL Drug Data Report (MDDR dataset was used for experiments and was represented by two 2D fingerprints, ALOGP and ECFP_4. The performance of voting-based consensus clustering method outperformed the Ward’s method using F-measure and QPI method for both ALOGP and ECFP_4 fingerprints, while the graph-based consensus clustering methods outperformed the Ward’s method only for ALOGP using QPI. The Jaccard and Euclidean distance measures were the methods of choice to generate the ensembles, which give the highest values for both criteria. Conclusions The results of the experiments show that consensus clustering methods can improve the effectiveness of chemical structures clusterings. The cumulative voting-based aggregation algorithm (CVAA was the method of choice among consensus clustering methods.

  13. Sunlight associated hyperthermia as a consistent and rapidly developing clinical sign in sheep intoxicated by St John's wort (Hypericum perforatum).

    Science.gov (United States)

    Bourke, C A

    2000-07-01

    To assess the usefulness of rectal temperature responses in Australian bred Merino sheep, following the oral administration of Hypericum perforatum (St John's wort), as an early indicator of Hypericum intolerance. Thirty-three Merino ewes were divided into three groups of 11. Each group was dosed with finely ground, dried, flowering growth stage H perforatum plant material at either 5.7, 4.0, or 2.85 g dry plant per kg live weight. This corresponded to 5.3, 3.7 and 2.65 mg hypericin per kg live weight, respectively. The sheep were dosed with a plant slurry by stomach tube and then exposed to bright sunlight for up to 5 h per day over successive days. Their clinical responses were observed and rectal temperature measured. Ingestion of H perforatum followed by exposure to bright sunlight frequently resulted in clinical signs attributable to skin irritation and central nervous effects, including an inappropriate increase in body temperature. A decrease in H perforatum ingestion from 5.7 to 2.85 g dry plant per kg live weight and a corresponding decrease in hypericin ingestion from 5.3 to 2.65 mg per kg live weight, was associated with a decrease in the severity of the clinical signs, including the severity of the hyperthermia. The rectal temperature rise in affected sheep is a reliable indicator of the early development of an adverse clinical effect. There appears to be an absolute requirement for exposure to bright sunlight before any effects of H perforatum will develop. A single dose of H perforatum remains potentially effective for up to 4 days. In the small group of Merino sheep tested a tolerance level for H perforatum, eaten at the flowering stage, of plant wet weight) of body weight and a tolerance level for hypericin of < 2.65 mg per kg live weight, were demonstrated.

  14. Sunlight and the 5-year incidence of early age-related maculopathy: the beaver dam eye study.

    Science.gov (United States)

    Cruickshanks, K J; Klein, R; Klein, B E; Nondahl, D M

    2001-02-01

    To investigate the relation of sunlight exposure and indicators of sun sensitivity with the 5-year incidence of early age-related maculopathy (ARM). Longitudinal, population-based study. Participants (aged 43-86 years at baseline) in the Beaver Dam Eye Study were reexamined from 1993 to 1995, 5 years after the baseline examination. Questionnaire data about sunlight exposure and sun sensitivity were obtained at baseline. Additional information about earlier life patterns of exposure was ascertained at follow-up. Stereoscopic color fundus photographs were graded to determine the presence of ARM at the 5-year follow-up in eyes free from signs of early ARM at the baseline examination. Leisure time spent outdoors while persons were teenagers (aged 13-19 years) and in their 30s (aged 30-39 years) was significantly associated with the risk of early ARM (odds ratio, 2.09; 95% confidence interval, 1.19-3.65). There was a slight, but nonsignificant, protective effect associated with use of hats and sunglasses while persons were teenagers and in their 30s (odds ratio, 0.72; 95% confidence interval, 0.50-1.03). People with red or blond hair were slightly more likely to develop early ARM than people with darker hair (odds ratio, 1.33; 95% confidence interval, 0.97-1.83). There were no associations between estimated ambient UV-B exposure or markers of sun sensitivity and the incidence of early ARM. Exposure to sunlight may be associated with the development of early ARM.

  15. Collaborative Clustering for Sensor Networks

    Science.gov (United States)

    Wagstaff. Loro :/; Green Jillian; Lane, Terran

    2011-01-01

    Traditionally, nodes in a sensor network simply collect data and then pass it on to a centralized node that archives, distributes, and possibly analyzes the data. However, analysis at the individual nodes could enable faster detection of anomalies or other interesting events, as well as faster responses such as sending out alerts or increasing the data collection rate. There is an additional opportunity for increased performance if individual nodes can communicate directly with their neighbors. Previously, a method was developed by which machine learning classification algorithms could collaborate to achieve high performance autonomously (without requiring human intervention). This method worked for supervised learning algorithms, in which labeled data is used to train models. The learners collaborated by exchanging labels describing the data. The new advance enables clustering algorithms, which do not use labeled data, to also collaborate. This is achieved by defining a new language for collaboration that uses pair-wise constraints to encode useful information for other learners. These constraints specify that two items must, or cannot, be placed into the same cluster. Previous work has shown that clustering with these constraints (in isolation) already improves performance. In the problem formulation, each learner resides at a different node in the sensor network and makes observations (collects data) independently of the other learners. Each learner clusters its data and then selects a pair of items about which it is uncertain and uses them to query its neighbors. The resulting feedback (a must and cannot constraint from each neighbor) is combined by the learner into a consensus constraint, and it then reclusters its data while incorporating the new constraint. A strategy was also proposed for cleaning the resulting constraint sets, which may contain conflicting constraints; this improves performance significantly. This approach has been applied to collaborative

  16. Hierarchical modeling of cluster size in wildlife surveys

    Science.gov (United States)

    Royle, J. Andrew

    2008-01-01

    Clusters or groups of individuals are the fundamental unit of observation in many wildlife sampling problems, including aerial surveys of waterfowl, marine mammals, and ungulates. Explicit accounting of cluster size in models for estimating abundance is necessary because detection of individuals within clusters is not independent and detectability of clusters is likely to increase with cluster size. This induces a cluster size bias in which the average cluster size in the sample is larger than in the population at large. Thus, failure to account for the relationship between delectability and cluster size will tend to yield a positive bias in estimates of abundance or density. I describe a hierarchical modeling framework for accounting for cluster-size bias in animal sampling. The hierarchical model consists of models for the observation process conditional on the cluster size distribution and the cluster size distribution conditional on the total number of clusters. Optionally, a spatial model can be specified that describes variation in the total number of clusters per sample unit. Parameter estimation, model selection, and criticism may be carried out using conventional likelihood-based methods. An extension of the model is described for the situation where measurable covariates at the level of the sample unit are available. Several candidate models within the proposed class are evaluated for aerial survey data on mallard ducks (Anas platyrhynchos).

  17. Using Microporous Polytetrafluoroethylene Thin Sheets as a Flexible Solar Diffuser to Minimize Sunlight Glint to Cameras in Space

    Science.gov (United States)

    Choi, Michael K.

    2016-01-01

    An innovative design of using microporous PTFE thin sheets as a solar diffuser for MLI blankets or mechanical structure has been developed. It minimizes sunlight or stray-light glint to cameras when it is incident on these components in space. A microporous black PTFE thin sheet solar diffuser has been qualified for flight at NASA GSFC and installed to the TAGSAM arm MLI, OCAMS PolyCam sunshade MLI and SamCam motor riser MLI in the NASA OSIRIS-REx mission to meet the SamCam camera BRDF requirement.

  18. Porous graphitic carbon nitride synthesized via direct polymerization of urea for efficient sunlight-driven photocatalytic hydrogen production

    Science.gov (United States)

    Zhang, Yuewei; Liu, Jinghai; Wu, Guan; Chen, Wei

    2012-08-01

    Energy captured directly from sunlight provides an attractive approach towards fulfilling the need for green energy resources on the terawatt scale with minimal environmental impact. Collecting and storing solar energy into fuel through photocatalyzed water splitting to generate hydrogen in a cost-effective way is desirable. To achieve this goal, low cost and environmentally benign urea was used to synthesize the metal-free photocatalyst graphitic carbon nitride (g-C3N4). A porous structure is achieved via one-step polymerization of the single precursor. The porous structure with increased BET surface area and pore volume shows a much higher hydrogen production rate under simulated sunlight irradiation than thiourea-derived and dicyanamide-derived g-C3N4. The presence of an oxygen atom is presumed to play a key role in adjusting the textural properties. Further improvement of the photocatalytic function can be expected with after-treatment due to its rich chemistry in functionalization.Energy captured directly from sunlight provides an attractive approach towards fulfilling the need for green energy resources on the terawatt scale with minimal environmental impact. Collecting and storing solar energy into fuel through photocatalyzed water splitting to generate hydrogen in a cost-effective way is desirable. To achieve this goal, low cost and environmentally benign urea was used to synthesize the metal-free photocatalyst graphitic carbon nitride (g-C3N4). A porous structure is achieved via one-step polymerization of the single precursor. The porous structure with increased BET surface area and pore volume shows a much higher hydrogen production rate under simulated sunlight irradiation than thiourea-derived and dicyanamide-derived g-C3N4. The presence of an oxygen atom is presumed to play a key role in adjusting the textural properties. Further improvement of the photocatalytic function can be expected with after-treatment due to its rich chemistry in

  19. Sunlight and the 10-year incidence of age-related maculopathy: the Beaver Dam Eye Study.

    Science.gov (United States)

    Tomany, Sandra C; Cruickshanks, Karen J; Klein, Ronald; Klein, Barbara E K; Knudtson, Michael D

    2004-05-01

    To examine the association of sunlight exposure and indicators of sun sensitivity with the 10-year incidence of age-related maculopathy (ARM). Population-based cohort study. We included persons aged 43 to 86 years at the baseline examination from 1988 to 1990, living in Beaver Dam, Wis, of whom 3684 persons underwent 5-year follow-up and 2764 underwent 10-year follow-up. Data on sun exposure and indicators of sun sensitivity were obtained from a standardized questionnaire administered at baseline and/or follow-up. We determined ARM status by grading stereoscopic color fundus photographs using the Wisconsin Age-Related Maculopathy Grading System. Incidence and progression of ARM. While controlling for age and sex, we found that participants exposed to the summer sun for more than 5 hours a day during their teens, in their 30s, and at the baseline examination were at a higher risk of developing increased retinal pigment (risk ratio [RR], 2.99; 95% confidence interval [CI], 1.18-7.60; P =.02) and early ARM (RR, 2.20; 95% CI, 1.02-4.73; P =.04) [corrected] by 10 years than those exposed less than 2 hours per day during the same periods. In participants reporting the highest summer sun exposure levels in their teens and 30s, the use of hats and sunglasses at least half the time during the same periods was associated with a decreased risk of developing soft indistinct drusen (RR, 0.55; 95% CI, 0.33-0.90; P =.02) and retinal pigment epithelial depigmentation (RR, 0.51; 95% CI, 0.29-0.91; P =.02). Participants who experienced more than 10 severe sunburns during their youth were more likely than those who experienced 1 or no burn to develop drusen with a 250-microm diameter or larger (RR, 2.52; 95% CI, 1.29-4.94 [corrected] P =.01) by the 10-year examination. No relationships were found between UV-B exposure, winter leisure time spent outdoors, skin sun sensitivity, or number of bad sunburns experienced by the time of the baseline examination and the 10-year incidence and

  20. Patterns and timing of sunlight exposure and risk of basal cell and squamous cell carcinomas of the skin – a case–control study

    Directory of Open Access Journals (Sweden)

    Iannacone Michelle R

    2012-09-01

    Full Text Available Abstract Background Non-melanoma skin cancer (NMSC, comprised of basal (BCC and squamous (SCC cell carcinomas, is the most common cancer in Caucasians. Ultraviolet radiation (UVR exposure is the most important environmental risk factor for NMSC. However, the precise relationship between UVR and the risk of NMSC is complex, and the relationship may differ by skin cancer type. Methods A case–control study was conducted among Florida residents to investigate measures of patterns (intermittent vs. continuous and timing (childhood vs. adulthood of sunlight exposure in BCC and SCC. Participants included 218 BCC and 169 SCC cases recruited from a university dermatology clinic and 316 controls with no history of skin or other cancers. Results A history of blistering sunburn (a measure of intermittent sunlight exposure was associated with both BCC (OR = 1.96, 95% CI = 1.27-3.03 and SCC (OR = 2.02, 95% CI = 1.22-3.33. Additionally, having a job in the sun for ≥3 months for 10 years or longer (a measure of continuous sunlight exposure was also associated with both BCC and SCC in our study population. With the exception of younger age at first blistering sunburn, measures of younger age at sunlight exposure tended to be associated with SCC, but not BCC risk. Conclusions Results from the current study suggest that sunlight exposure is associated with both BCC and SCC risk regardless of the pattern in which the exposure was received (i.e. intermittent vs. continuous. The data also suggest that sunlight exposure at a younger age may be more important for SCC but not BCC, however additional studies are needed to further characterize sunlight exposure-response relationships in different types of NMSC.

  1. Patterns and timing of sunlight exposure and risk of basal cell and squamous cell carcinomas of the skin--a case-control study.

    Science.gov (United States)

    Iannacone, Michelle R; Wang, Wei; Stockwell, Heather G; O'Rourke, Kathleen; Giuliano, Anna R; Sondak, Vernon K; Messina, Jane L; Roetzheim, Richard G; Cherpelis, Basil S; Fenske, Neil A; Rollison, Dana E

    2012-09-20

    Non-melanoma skin cancer (NMSC), comprised of basal (BCC) and squamous (SCC) cell carcinomas, is the most common cancer in Caucasians. Ultraviolet radiation (UVR) exposure is the most important environmental risk factor for NMSC. However, the precise relationship between UVR and the risk of NMSC is complex, and the relationship may differ by skin cancer type. A case-control study was conducted among Florida residents to investigate measures of patterns (intermittent vs. continuous) and timing (childhood vs. adulthood) of sunlight exposure in BCC and SCC. Participants included 218 BCC and 169 SCC cases recruited from a university dermatology clinic and 316 controls with no history of skin or other cancers. A history of blistering sunburn (a measure of intermittent sunlight exposure) was associated with both BCC (OR = 1.96, 95% CI = 1.27-3.03) and SCC (OR = 2.02, 95% CI = 1.22-3.33). Additionally, having a job in the sun for ≥ 3 months for 10 years or longer (a measure of continuous sunlight exposure) was also associated with both BCC and SCC in our study population. With the exception of younger age at first blistering sunburn, measures of younger age at sunlight exposure tended to be associated with SCC, but not BCC risk. Results from the current study suggest that sunlight exposure is associated with both BCC and SCC risk regardless of the pattern in which the exposure was received (i.e. intermittent vs. continuous). The data also suggest that sunlight exposure at a younger age may be more important for SCC but not BCC, however additional studies are needed to further characterize sunlight exposure-response relationships in different types of NMSC.

  2. Patterns and timing of sunlight exposure and risk of basal cell and squamous cell carcinomas of the skin – a case–control study

    Science.gov (United States)

    2012-01-01

    Background Non-melanoma skin cancer (NMSC), comprised of basal (BCC) and squamous (SCC) cell carcinomas, is the most common cancer in Caucasians. Ultraviolet radiation (UVR) exposure is the most important environmental risk factor for NMSC. However, the precise relationship between UVR and the risk of NMSC is complex, and the relationship may differ by skin cancer type. Methods A case–control study was conducted among Florida residents to investigate measures of patterns (intermittent vs. continuous) and timing (childhood vs. adulthood) of sunlight exposure in BCC and SCC. Participants included 218 BCC and 169 SCC cases recruited from a university dermatology clinic and 316 controls with no history of skin or other cancers. Results A history of blistering sunburn (a measure of intermittent sunlight exposure) was associated with both BCC (OR = 1.96, 95% CI = 1.27-3.03) and SCC (OR = 2.02, 95% CI = 1.22-3.33). Additionally, having a job in the sun for ≥3 months for 10 years or longer (a measure of continuous sunlight exposure) was also associated with both BCC and SCC in our study population. With the exception of younger age at first blistering sunburn, measures of younger age at sunlight exposure tended to be associated with SCC, but not BCC risk. Conclusions Results from the current study suggest that sunlight exposure is associated with both BCC and SCC risk regardless of the pattern in which the exposure was received (i.e. intermittent vs. continuous). The data also suggest that sunlight exposure at a younger age may be more important for SCC but not BCC, however additional studies are needed to further characterize sunlight exposure-response relationships in different types of NMSC. PMID:22994655

  3. Knowledge of vitamin D and perceptions and attitudes toward sunlight among Chinese middle-aged and elderly women: a population survey in Hong Kong

    Directory of Open Access Journals (Sweden)

    Lee Ka-Kui

    2006-09-01

    Full Text Available Abstract Background Physical and biological risk factors for vitamin D inadequacy are known; however, cultural- and population-specific behaviours and attitudes that influence these risk factors, particularly among Asian people, are less well documented. To understand more about prevailing attitudes and behaviour toward sunlight and knowledge of vitamin D among a population at greater risk of impaired vitamin D status, poor bone health and osteoporosis, we conducted a telephone interview survey of 547 middle-aged and elderly Chinese women living in Hong Kong. Methods All telephone interviews were conducted using the Computer Assisted Telephone Technique and target respondents were selected by random sampling. Interviews were conducted in Cantonese and eighteen main questions were asked pertaining to personal characteristics, perceptions, attitudes and behaviour toward sunlight, and knowledge about vitamin D. Results The survey results showed that 62.3% (n = 341 did not like going in the sun and 66.7% of respondents spent an average of 6–10 hours indoors, between 6:30 am and 7:00 pm, during weekdays. However, 58% of people thought that they had enough exposure to sunlight. The majority had heard of vitamin D, but knowledge about the role and sources of vitamin D was low. Among those who knew that sunlight was a source of vitamin D, the majority spent less than 1 h in the sun in the past week (76.4% vs 23.6%, 1 h in the sun in the past week, chi-square p Conclusion The survey revealed considerable ignorance and confusion about the role of sunlight in vitamin D production, and the function and sources of vitamin D. Attitudes and behaviour toward sunlight were largely negative and many took measures to avoid sunlight, particularly among younger (middle-aged women who had good awareness of vitamin D.

  4. What Makes Clusters Decline?

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter; Park, Eun Kyung

    2015-01-01

    Most studies on regional clusters focus on identifying factors and processes that make clusters grow. However, sometimes technologies and market conditions suddenly shift, and clusters decline. This paper analyses the process of decline of the wireless communication cluster in Denmark....... The longitudinal study on the high-tech cluster reveals that technological lock-in and exit of key firms have contributed to decline. Entrepreneurship has a positive effect on the cluster’s adaptive capabilities, while multinational companies have contradicting effects by bringing in new resources to the cluster...

  5. Comprehensive cluster analysis with Transitivity Clustering.

    Science.gov (United States)

    Wittkop, Tobias; Emig, Dorothea; Truss, Anke; Albrecht, Mario; Böcker, Sebastian; Baumbach, Jan

    2011-03-01

    Transitivity Clustering is a method for the partitioning of biological data into groups of similar objects, such as genes, for instance. It provides integrated access to various functions addressing each step of a typical cluster analysis. To facilitate this, Transitivity Clustering is accessible online and offers three user-friendly interfaces: a powerful stand-alone version, a web interface, and a collection of Cytoscape plug-ins. In this paper, we describe three major workflows: (i) protein (super)family detection with Cytoscape, (ii) protein homology detection with incomplete gold standards and (iii) clustering of gene expression data. This protocol guides the user through the most important features of Transitivity Clustering and takes ∼1 h to complete.

  6. Incorporating Contact Network Structure in Cluster Randomized Trials

    CERN Document Server

    Staples, Patrick C; Onnela, Jukka-Pekka

    2015-01-01

    Whenever possible, the efficacy of a new treatment, such as a drug or behavioral intervention, is investigated by randomly assigning some individuals to a treatment condition and others to a control condition, and comparing the outcomes between the two groups. Often, when the treatment aims to slow an infectious disease, groups or clusters of individuals are assigned en masse to each treatment arm. The structure of interactions within and between clusters can reduce the power of the trial, i.e. the probability of correctly detecting a real treatment effect. We investigate the relationships among power, within-cluster structure, between-cluster mixing, and infectivity by simulating an infectious process on a collection of clusters. We demonstrate that current power calculations may be conservative for low levels of between-cluster mixing, but failing to account for moderate or high amounts can result in severely underpowered studies. Power also depends on within-cluster network structure for certain kinds of i...

  7. Geographical clustering of incident acute myocardial infarction in Denmark

    DEFF Research Database (Denmark)

    Kjærulff, Thora Majlund; Ersbøll, Annette Kjær; Gislason, Gunnar

    2016-01-01

    OBJECTIVES: To examine the geographical patterns in AMI and characterize individual and neighborhood sociodemographic factors for persons living inside versus outside AMI clusters. METHODS: The study population comprised 3,515,670 adults out of whom 74,126 persons experienced an incident AMI (200...... versus outside AMI clusters. CONCLUSIONS: AMI is geographically unequally distributed throughout Denmark and determinants of these geographical patterns might include individual- and neighborhood-level sociodemographic factors.......OBJECTIVES: To examine the geographical patterns in AMI and characterize individual and neighborhood sociodemographic factors for persons living inside versus outside AMI clusters. METHODS: The study population comprised 3,515,670 adults out of whom 74,126 persons experienced an incident AMI (2005......-2011). Kernel density estimation and global and local clustering methods were used to examine the geographical patterns in AMI. Median differences and frequency distributions of sociodemographic factors were calculated for persons living inside versus outside AMI clusters. RESULTS: Global clustering of AMI...

  8. The Cluster Substructure - Alignment Connection

    OpenAIRE

    Plionis, Manolis

    2001-01-01

    Using the APM cluster data we investigate whether the dynamical status of clusters is related to the large-scale structure of the Universe. We find that cluster substructure is strongly correlated with the tendency of clusters to be aligned with their nearest neighbour and in general with the nearby clusters that belong to the same supercluster. Furthermore, dynamically young clusters are more clustered than the overall cluster population. These are strong indications that cluster develop in ...

  9. Photosensitized mefloquine induces ROS-mediated DNA damage and apoptosis in keratinocytes under ambient UVB and sunlight exposure.

    Science.gov (United States)

    Yadav, Neera; Dwivedi, Ashish; Mujtaba, Syed Faiz; Verma, Ankit; Chaturvedi, Rajnish; Ray, Ratan Singh; Singh, Gajendra

    2014-10-01

    The present study illustrates the photosensitizing behavior of mefloquine (MQ) in human skin keratinocytes under ambient doses of UVB and sunlight exposure. Photochemically, MQ generated reactive oxygen species superoxide radical, hydroxyl radical, and singlet oxygen through type I and type II photodynamic reactions, respectively, which caused photooxidative damage to DNA and formed localized DNA lesions cyclobutane pyrimidine dimers. Photosensitized MQ reduced the viability of keratinocytes to 25 %. Significant level of intracellular reactive oxygen species (ROS) generation was estimated through fluorescence probe DCF-H2. Increased apoptotic cells were evident through AO/EB staining and phosphatidyl serine translocation in cell membrane. Single-stranded DNA damage was marked through single-cell gel electrophoresis. Mitochondrial membrane depolarization and lysosomal destabilization were evident. Upregulation of Bax and p21 and downregulation of Bcl-2 genes and corresponding protein levels supported apoptotic cell death of keratinocyte cells. Cyclobutane pyrimidine dimers (CPDs) were confirmed through immunofluorescence. In addition, hallmarks of apoptosis and G2/M phase cell cycle arrest were confirmed through flow cytometry analysis. Our findings suggest that MQ may damage DNA and produce DNA lesions which may induce differential biological responses in the skin on brief exposure to UVB and sunlight.

  10. Interactions of ozone with organic surface films in the presence of simulated sunlight: impact on wettability of aerosols.

    Science.gov (United States)

    Nieto-Gligorovski, L; Net, S; Gligorovski, S; Zetzsch, C; Jammoul, A; D'Anna, B; George, C

    2008-05-28

    Heterogeneous reactions between organic films, taken as proxies for atmospheric aerosols, with ozone in presence of simulated sunlight and the photosensitizer 4-carboxybenzophenone (4-CB) were observed to alter surface properties as monitored by contact angle during the reaction. Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) was used in addition for product identification. Two types of model surfaces were systematically studied: 4-CB/4-phenoxyphenol and 4-CB/catechol. Solid organic films made of 4-CB/catechol were observed to become hydrophilic by simultaneous exposure to ozone and simulated sunlight, whereas organic films made of 4-CB/4-phenoxyphenol become hydrophobic under the same conditions. These changes in contact angle indicate that photo-induced aging processes involving ozone (such as oligomerisation) not necessarily favour increased hygroscopicity of organic aerosols in the atmosphere. The ratio between hydrophobic and hydrophilic functional groups should reflect the chemical property of organic films with respect to wettability phenomena. Contact angles and surface tensions of the exposed organic film made of 4-CB/4-phenoxyphenol were found to correspond to the hydrophobic/hydrophilic ratios obtained from the FTIR-ATR spectra.

  11. Sunlight Triggers Cutaneous Lupus through a Colony Stimulating Factor-1 (CSF-1) Dependent Mechanism in MRL-Faslpr mice

    Science.gov (United States)

    Menke, Julia; Hsu, Mei-Yu; Byrne, Katelyn T.; Lucas, Julie A.; Rabacal, Whitney A.; Croker, Byron P.; Zong, Xiao-Hua; Stanley, E. Richard; Kelley, Vicki R.

    2008-01-01

    Sunlight (UVB) triggers cutaneous (CLE) and systemic lupus through an unknown mechanism. We tested the hypothesis that UVB triggers CLE through a CSF-1-dependent, macrophage (Mø) -mediated mechanism in MRL-Faslpr mice. By constructing mutant MRL-Faslpr strains expressing varying levels of CSF-1 (high, intermediate, none), and use of an ex-vivo gene transfer to deliver CSF-1 intra-dermally, we determined that CSF-1 induces CLE in lupus-susceptible, MRL-Faslpr mice, but not in lupus-resistant, BALB/c mice. Notably, UVB incites an increase in Mø, apoptosis in the skin and CLE in MRL-Faslpr, but not in CSF-1-deficient MRL-Faslpr mice. Furthermore, UVB did not induce CLE in BALB/c mice. Probing further, UVB stimulates CSF-1 expression by keratinocytes leading to recruitment and activation of Mø that, in turn, release mediators, which induce apoptosis in keratinocytes. Thus, sunlight triggers a CSF-1-dependent, Mø-mediated destructive inflammation in the skin leading to CLE in lupus-susceptible MRL-Faslpr, but not lupus-resistant BALB/c mice. Taken together, we envision CSF-1 as the “match” and lupus-susceptibility as the “tinder” leading to CLE. PMID:18981160

  12. Test of a device for accelerated ageing of polymeric material in high concentrated sunlight at the DLR solar furnace

    Energy Technology Data Exchange (ETDEWEB)

    Witzke, A.; Neumann, A.; Kaluza, J. [German Aerospace Center (DLR), Solar Energy Technology, Cologne (Germany); Demuth, M.; Ritterskamp, P. [Max-Planck-Inst. fuer Strahlenchemie, Muelheim a.d.R. (Germany)

    2001-07-01

    Within this study the design and first tests of a device for accelerated ageing with high concentrated sunlight have been described. Firstly, the device was designed for testing samples of lacquer for the car industry. It is based on two points: first, the photochemical effect that the ageing of polymers is mainly initiated by the UV solar radiation and, second, on the idea to accelerate the ageing process by increasing the UV radiation dose. Therefore the concentrated sunlight at the DLR Solar Furnace is filtered by a cold-mirror that reflects the radiation with a wavelength below 450 nm onto the samples. The samples are fixed in a chamber where they can simultaneously be wetted by a spraying device. The first tests show that this device enables us to radiate the relevant samples with a high UV radiation intensity without overheating them. During one day irradiation at the DLR Solar Furnace in March 2001 we reach an UV radiation dose which is about sixteen times higher than the dose after 24 hours irradiation in common used weathering devices. Further tests at the DLR Solar Furnace have to examine in what way this increased radiation dose leads to a high accelerated ageing of the polymeric material. (orig.)

  13. Enhanced photocatalytic activity of TiO2 under sunlight by MoS2 nanodots modification

    Science.gov (United States)

    Wang, Ding; Xu, Ying; Sun, Feng; Zhang, Quanhua; Wang, Ping; Wang, Xianying

    2016-07-01

    In this study, MoS2 nanodots modified TiO2 (P25) composite photocatalyst (MoS2/P25) was fabricated via a facile liquid ultrasonic mixing method. Compared to the pure P25, the MoS2/P25 exhibited improved photocatalytic degradation activity under simulated sunlight with rhodamine B (RhB) and methylene blue (MB) as the target pollutants. RhB or MB (40 mL 10 mg/L) completely degraded within 20 min, and the kinetic constant reached 0.221 and 0.253 min-1 for RhB and MB, respectively. Based on the characterization of transient photocurrent response measurement and UV-vis diffuse reflectance spectra, a possible photocatalytic mechanism was proposed. The enhanced photocatalytic performance was attributed to the heterostructure of P25 and MoS2 nanodots, improving their charge separation and enhancing their absorption capacity to the full sunlight spectrum. We believe that this study will contribute to the development of new photocatalysts and improving the catalytic performance of traditional photocatalysts.

  14. Polydopamine-Coated Porous Substrates as a Platform for Mineralized β-FeOOH Nanorods with Photocatalysis under Sunlight.

    Science.gov (United States)

    Zhang, Chao; Yang, Hao-Cheng; Wan, Ling-Shu; Liang, Hong-Qing; Li, Hanying; Xu, Zhi-Kang

    2015-06-03

    Immobilization of photo-Fenton catalysts on porous materials is crucial to the efficiency and stability for water purification. Here we report polydopamine (PDA)-coated porous substrates as a platform for in situ mineralizing β-FeOOH nanorods with enhanced photocatalytic performance under sunlight. The PDA coating plays multiple roles as an adhesive interface, a medium inducing mineral generation, and an electron transfer layer. The mineralized β-FeOOH nanorods perfectly wrap various porous substrates and are stable on the substrates that have a PDA coating. The immobilized β-FeOOH nanorods have been shown to be efficient for degrading dyes in water via a photo-Fenton reaction. The degradation efficiency reaches approximately 100% in 60 min when the reaction was carried out with H2O2 under visible light, and it remains higher than 90% after five cycles. We demonstrate that the PDA coating promotes electron transfer to reduce the electron-hole recombination rate. As a result, the β-FeOOH nanorods wrapped on the PDA-coated substrates show enhanced photocatalytic performance under direct sunlight in the presence of H2O2. Moreover, this versatile platform using porous materials as the substrate is useful in fabricating β-FeOOH nanorods-based membrane reactor for wastewater treatment.

  15. Sunlight-Sensitive Anti-Fouling Nanostructured TiO2 coated Cu Meshes for Ultrafast Oily Water Treatment

    Science.gov (United States)

    Liu, Haoran; Raza, Aikifa; Aili, Abulimiti; Lu, Jinyou; Alghaferi, Amal; Zhang, Tiejun

    2016-05-01

    Nanostructured materials with desired wettability and optical property can play an important role in reducing the energy consumption of oily water treatment technologies. For effective oily water treatment, membrane materials with high strength, sunlight-sensitive anti-fouling, relative low fabrication cost, and controllable wettability are being explored. In the proposed oily water treatment approach, nanostructured TiO2-coated copper (TNS-Cu) meshes are used. These TNS-Cu meshes exhibit robust superhydrophilicity and underwater oleophobicity (high oil intrusion pressure) as well as excellent chemical and thermal stability (≈250 °C). They have demonstrated high separation efficiency (oil residue in the filtrate ≤21.3 ppm), remarkable filtration flux (≥400 kL h-1 m-2), and sunlight-sensitive anti-fouling properties. Both our theoretical analysis and experimental characterization have confirmed the enhanced light absorption property of TNS-Cu meshes in the visible region (40% of the solar spectrum) and consequently strong anti-fouling capability upon direct solar light illumination. With these features, the proposed approach promises great potential in treating produced oily wastewater from industry and daily life.

  16. A new family of sunlight-driven bifunctional photocatalysts based on TiO₂ nanoribbon frameworks and bismuth oxohalide nanoplates.

    Science.gov (United States)

    Cao, Xuebo; Lu, Zhufeng; Zhu, Lianwen; Yang, Le; Gu, Li; Cai, Liling; Chen, Jie

    2014-01-01

    By taking advantage of the structural affinity between bismuth oxohalide and TiO₂, we successfully prepare a family of hybrid frameworks via the designated growth of bismuth oxohalide nanoplates on TiO₂ nanoribbons, and propose them as sunlight-driven bifunctional photocatalysts for all-weather removal of pollutants. The structural variability of bismuth oxohalide allows the optical absorption of the hybrid framework to be monotonically tuneable across the visible spectrum. Meanwhile, the hybridization greatly increases the surface roughness of the frameworks and enables the frameworks to harvest more photons to participate in photocatalytic reactions. Furthermore, the hybridization establishes two potential gradients to promote the separation of photo-induced electron-hole pairs: the internal electrical field perpendicular to the wide surfaces of bismuth oxohalide nanoplates and across the semiconductor-semiconductor heterojunction. Owing to the synergetic effects of the permeable mesoporous architecture, the intense visible light absorption, and the efficient charge separation, the hybrid frameworks are capable of all-weather removal of pollutants: they utilize the inter-ribbon pores to gather pollutants in the dark (behaving as collectors) and they rapidly degrade the pollutants in the day (behaving as photocatalysts). In particular, the BiOBr@TiO₂ framework exhibits very impressive sunlight-driven photocatalytic activity, which is much higher than commercially available P25 TiO₂ under the same conditions.

  17. Nutrient Shielding in Clusters of Cells

    CERN Document Server

    Lavrentovich, Maxim O; Nelson, David R

    2013-01-01

    Cellular nutrient consumption is influenced by both the nutrient uptake kinetics of an individual cell and the cells' spatial arrangement. Large cell clusters or colonies have inhibited growth at the cluster's center due to the shielding of nutrients by the cells closer to the surface. We develop an effective medium theory that predicts a thickness $\\ell$ of the outer shell of cells in the cluster that receives enough nutrient to grow. The cells are treated as partially absorbing identical spherical nutrient sinks, and we identify a dimensionless parameter $\

  18. Cluster Analysis of the Malaysian Hipposideros

    Science.gov (United States)

    Sazali, Siti Nurlydia; Laman, Charlie J.; Abdullah, M. T.

    2008-01-01

    A preliminary study on the morphometric variations among species in the genus Hipposideros was conducted using voucher specimens from the Universiti Malaysia Sarawak (UNIMAS) Zoological Museum and the Department of Wildlife and National Park (DWNP) Kuala Lumpur. A total of 24 individuals from six species of this genus were morphologically studied where all related measurements of body, skull and dental were measured and recorded. The statistical data subjected to the cluster analysis shows that the genus Hipposideros is divided into two major clusters where each species was clearly separated. The cluster analysis among Hipposideros species is useful for aiding in species identification.

  19. Nuclear Clusters in Astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Kubono, S.; Binh, Dam N.; Hayakawa, S.; Hashimoto, H.; Kahl, D.; Wakabayashi, Y.; Yamaguchi, H. [Center for Nuclear Study (CNS), University of Tokyo, Wako Branch at RIKEN 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Teranishi, T. [Department of Physics, Kyushu University, Fukuoka, 812-8581 (Japan); Iwasa, N. [Department of Physics, Tohoku University, Sendai, 980-8578 (Japan); Komatsubara, T. [Department of Physics, Tsukuba University, Ibaraki, 305-8571 (Japan); Kato, S. [Department of Physics, Yamagata University, Yamagata, 990-8560 (Japan); Khiem, Le H. [Institute of Physics, Vietnam Academy for Science and Technology, Hanoi (Viet Nam)

    2010-03-01

    The role of nuclear clustering is discussed for nucleosynthesis in stellar evolution with Cluster Nucleosynthesis Diagram (CND) proposed before. Special emphasis is placed on alpha-induced stellar reactions together with molecular states for O and C burning.

  20. [Pathophysiology of cluster headache].

    Science.gov (United States)

    Donnet, Anne

    2015-11-01

    The aetiology of cluster headache is partially unknown. Three areas are involved in the pathogenesis of cluster headache: the trigeminal nociceptive pathways, the autonomic system and the hypothalamus. The cluster headache attack involves activation of the trigeminal autonomic reflex. A dysfunction located in posterior hypothalamic gray matter is probably pivotal in the process. There is a probable association between smoke exposure, a possible genetic predisposition and the development of cluster headache.

  1. Effect of grape bunch sunlight exposure and UV radiation on phenolics and volatile composition of Vitis vinifera L. cv. Pinot noir wine.

    Science.gov (United States)

    Song, Jianqiang; Smart, Richard; Wang, Hua; Dambergs, Bob; Sparrow, Angela; Qian, Michael C

    2015-04-15

    The effect of canopy leaf removal and ultraviolet (UV) on Pinot noir grape and wine composition was investigated in this study. Limited basal leaf removal in the fruit zone was conducted, compared to shaded bunches. The UV exposure was controlled using polycarbonate screens to block UV radiation, and acrylic screens to pass the UV. The results showed that bunch sunlight and UV exposure significantly increased the Brix and pH in the grape juice, and increased substantially wine colour density, anthocyanins, total pigment, total phenolics and tannin content. Bunch sunlight and UV exposure affected terpene alcohols, C13-norisprenoids and other volatile composition of the wine differently. Sunlight exposure and UV resulted in increase of nerol, geraniol and citronellol but not linalool. Sunlight exposure slightly increased the concentration of β-ionone, but the increase was not statistically significant for UV treatment. Neither sunlight nor UV treatment showed any impact on the concentration of β-damascenone. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. Cluster Physics with Merging Galaxy Clusters

    Directory of Open Access Journals (Sweden)

    Sandor M. Molnar

    2016-02-01

    Full Text Available Collisions between galaxy clusters provide a unique opportunity to study matter in a parameter space which cannot be explored in our laboratories on Earth. In the standard LCDM model, where the total density is dominated by the cosmological constant ($Lambda$ and the matter density by cold dark matter (CDM, structure formation is hierarchical, and clusters grow mostly by merging.Mergers of two massive clusters are the most energetic events in the universe after the Big Bang,hence they provide a unique laboratory to study cluster physics.The two main mass components in clusters behave differently during collisions:the dark matter is nearly collisionless, responding only to gravity, while the gas is subject to pressure forces and dissipation, and shocks and turbulenceare developed during collisions. In the present contribution we review the different methods used to derive the physical properties of merging clusters. Different physical processes leave their signatures on different wavelengths, thusour review is based on a multifrequency analysis. In principle, the best way to analyze multifrequency observations of merging clustersis to model them using N-body/HYDRO numerical simulations. We discuss the results of such detailed analyses.New high spatial and spectral resolution ground and space based telescopeswill come online in the near future. Motivated by these new opportunities,we briefly discuss methods which will be feasible in the near future in studying merging clusters.

  3. The Durban Auto Cluster

    DEFF Research Database (Denmark)

    Lorentzen, Jochen; Robbins, Glen; Barnes, Justin

    2004-01-01

    The paper describes the formation of the Durban Auto Cluster in the context of trade liberalization. It argues that the improvement of operational competitiveness of firms in the cluster is prominently due to joint action. It tests this proposition by comparing the gains from cluster activities i...

  4. The Durban Auto Cluster

    DEFF Research Database (Denmark)

    Lorentzen, Jochen; Robbins, Glen; Barnes, Justin

    2004-01-01

    The paper describes the formation of the Durban Auto Cluster in the context of trade liberalization. It argues that the improvement of operational competitiveness of firms in the cluster is prominently due to joint action. It tests this proposition by comparing the gains from cluster activities i...

  5. Marketing research cluster analysis

    Directory of Open Access Journals (Sweden)

    Marić Nebojša

    2002-01-01

    Full Text Available One area of applications of cluster analysis in marketing is identification of groups of cities and towns with similar demographic profiles. This paper considers main aspects of cluster analysis by an example of clustering 12 cities with the use of Minitab software.

  6. Information Propagation in Clustered Multilayer Networks

    CERN Document Server

    Zhuang, Yong

    2015-01-01

    In today's world, individuals interact with each other in more complicated patterns than ever. Some individuals engage through online social networks (e.g., Facebook, Twitter), while some communicate only through conventional ways (e.g., face-to-face). Therefore, understanding the dynamics of information propagation among humans calls for a multi-layer network model where an online social network is conjoined with a physical network. In this work, we initiate a study of information diffusion in a clustered multi-layer network model, where all constituent layers are random networks with high clustering. We assume that information propagates according to the SIR model and with different information transmissibility across the networks. We give results for the conditions, probability, and size of information epidemics, i.e., cases where information starts from a single individual and reaches a positive fraction of the population. We show that increasing the level of clustering in either one of the layers increas...

  7. Geographic Clustering and Productivity: An Instrumental Variable Approach for Classical Composers

    DEFF Research Database (Denmark)

    Borowiecki, Karol

    2013-01-01

    It is difficult to estimate the impact of geographic clustering on productivity because of endogeneity issues. I use birthplace-cluster distance as an instrumental variable for the incidence of clustering of prominent classical composers born between 1750 and 1899. I find that geographic clustering...... strongly impacts the productivity of the clustering individuals: composers were approx. 33 percentage points more productive while they remained in a geographic cluster. Top composers and composers who migrated to the cluster are the greatest beneficiaries of clustering. The benefit depends...

  8. Geographic Clustering and Productivity: An Instrumental Variable Approach for Classical Composers

    DEFF Research Database (Denmark)

    Borowiecki, Karol

    2013-01-01

    It is difficult to estimate the impact of geographic clustering on productivity because of endogeneity issues. I use birthplace-cluster distance as an instrumental variable for the incidence of clustering of prominent classical composers born between 1750 and 1899. I find that geographic clustering...... strongly impacts the productivity of the clustering individuals: composers were approx. 33 percentage points more productive while they remained in a geographic cluster. Top composers and composers who migrated to the cluster are the greatest beneficiaries of clustering. The benefit depends...

  9. Interventional treatment for cluster headache: a review of the options.

    Science.gov (United States)

    Rozen, Todd D

    2002-02-01

    There is no more severe pain than that sustained by a cluster headache sufferer. Surgical treatment of cluster headache should only be considered after a patient has exhausted all medical options or when a patient's medical history precludes the use of typical cluster abortive and preventive medications. Once a cluster patient is deemed a medical failure only those who have strictly side-fixed headaches should be considered for surgery. Other criteria for cluster surgery include pain localizing to the ophthalmic division of the trigeminal nerve, a psychologically stable individual, and absence of addictive personality traits. To understand the rationale behind the surgical treatment strategies for cluster, one must have a general understanding of the anatomy of cluster pathogenesis. The most frequently used surgical techniques for cluster are directed toward the sensory trigeminal nerve and the cranial parasympathetic system.

  10. Clustering Algorithm Based on Crowding Niche%小生境排挤聚类算法

    Institute of Scientific and Technical Information of China (English)

    业宁; 董逸生

    2003-01-01

    A new clustering algorithm is proposed in this paper, which is based on crowding niche. Homogeneityspontaneous to withstands heterogeneity when organisms are evolving. Contemporary, Individual in same class com-pete each other to strive for limited resource. Individual that has bad fitness will be eliminated. We propose a cluster-ing algorithm based on this idea. Experiment evaluation has proved its efficiency.

  11. Mass Distribution in Galaxy Cluster Cores

    Science.gov (United States)

    Hogan, M. T.; McNamara, B. R.; Pulido, F.; Nulsen, P. E. J.; Russell, H. R.; Vantyghem, A. N.; Edge, A. C.; Main, R. A.

    2017-03-01

    Many processes within galaxy clusters, such as those believed to govern the onset of thermally unstable cooling and active galactic nucleus feedback, are dependent upon local dynamical timescales. However, accurate mapping of the mass distribution within individual clusters is challenging, particularly toward cluster centers where the total mass budget has substantial radially dependent contributions from the stellar (M *), gas (M gas), and dark matter (M DM) components. In this paper we use a small sample of galaxy clusters with deep Chandra observations and good ancillary tracers of their gravitating mass at both large and small radii to develop a method for determining mass profiles that span a wide radial range and extend down into the central galaxy. We also consider potential observational pitfalls in understanding cooling in hot cluster atmospheres, and find tentative evidence for a relationship between the radial extent of cooling X-ray gas and nebular Hα emission in cool-core clusters. At large radii the entropy profiles of our clusters agree with the baseline power law of K ∝ r 1.1 expected from gravity alone. At smaller radii our entropy profiles become shallower but continue with a power law of the form K ∝ r 0.67 down to our resolution limit. Among this small sample of cool-core clusters we therefore find no support for the existence of a central flat “entropy floor.”

  12. Immunodominance and clonal selection inspired multiobjective clustering

    Institute of Scientific and Technical Information of China (English)

    Wenping Ma; Licheng Jiao; Maoguo Gong

    2009-01-01

    The biological immune system is a highly parallel and distributed adaptive system. The information processing abilities of the immune system provide important insights into the field of computation. Based on immunodominance in the biological immune system and the clonal selection mechanism, a novel data mining method, Immune Dominance Clonal Multiobjective Clustering algorithm (IDCMC), is presented. The algorithm divides an individual population into three sub-populations according to three different measurements, and adopts different evolution and selection strategies for each sub-population. The update of each sub-population, however, is not carried out in isolation. The periodic combination operation of the analysis of the three sub-populations represents considerable advantages in its global search ability. The clustering task is a multiobjective optimization problem, which is more robust with respect to the variety of cluster structures of different datasets than a single-objective clustering algorithm. In addition, the new algorithm can determine the num-ber of clusters automatically, which should identify the most promising clustering solutions in the candidate set. The experimental results, using artificial datasets with different manifold structure and handwritten digit datasets, show that the IDCMC outperforms the PESA-ll-based clustering method, the genetic algorithm-based clustering technique and the original K-Means algorithm in solving most of the problems tested.

  13. Clustering of Web Learners Based on Rough Set

    Institute of Scientific and Technical Information of China (English)

    LIU Shuai-dong; CHEN Shi-hong

    2004-01-01

    The demand for individualized teaching from E-learning websites is rapidly increasing due to the huge differences existed among Web learners.A method for clustering Web learners based on rough set is proposed.The basic idea of the method is to reduce the learning attributes prior to clustering, and therefore the clustering of Web learners is carried out in a relative low-dimensional space.Using this method, the E-learning websites can arrange corresponding teaching content for different clusters of learners so that the learners' individual requirements can be more satisfied.

  14. Cluster analysis for applications

    CERN Document Server

    Anderberg, Michael R

    1973-01-01

    Cluster Analysis for Applications deals with methods and various applications of cluster analysis. Topics covered range from variables and scales to measures of association among variables and among data units. Conceptual problems in cluster analysis are discussed, along with hierarchical and non-hierarchical clustering methods. The necessary elements of data analysis, statistics, cluster analysis, and computer implementation are integrated vertically to cover the complete path from raw data to a finished analysis.Comprised of 10 chapters, this book begins with an introduction to the subject o

  15. Range-Clustering Queries

    OpenAIRE

    Abrahamsen, Mikkel; de Berg, Mark; Buchin, Kevin; Mehr, Mehran; Mehrabi, Ali D.

    2017-01-01

    In a geometric $k$-clustering problem the goal is to partition a set of points in $\\mathbb{R}^d$ into $k$ subsets such that a certain cost function of the clustering is minimized. We present data structures for orthogonal range-clustering queries on a point set $S$: given a query box $Q$ and an integer $k>2$, compute an optimal $k$-clustering for $S\\setminus Q$. We obtain the following results. We present a general method to compute a $(1+\\epsilon)$-approximation to a range-clustering query, ...

  16. Cluster Decline and Resilience

    DEFF Research Database (Denmark)

    Østergaard, Christian Richter; Park, Eun Kyung

    -2011. Our longitudinal study reveals that technological lock-in and exit of key firms have contributed to impairment of the cluster’s resilience in adapting to disruptions. Entrepreneurship has a positive effect on cluster resilience, while multinational companies have contradicting effects by bringing......Most studies on regional clusters focus on identifying factors and processes that make clusters grow. However, sometimes technologies and market conditions suddenly shift, and clusters decline. This paper analyses the process of decline of the wireless communication cluster in Denmark, 1963...

  17. Management of cluster headache

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer C; Jensen, Rigmor H

    2012-01-01

    and agitation. Patients may have up to eight attacks per day. Episodic cluster headache (ECH) occurs in clusters of weeks to months duration, whereas chronic cluster headache (CCH) attacks occur for more than 1 year without remissions. Management of cluster headache is divided into acute attack treatment....... In drug-resistant CCH, neuromodulation with either occipital nerve stimulation or deep brain stimulation of the hypothalamus is an alternative treatment strategy. For most cluster headache patients there are fairly good treatment options both for acute attacks and for prophylaxis. The big problem...

  18. Clusters in nuclei

    CERN Document Server

    Following the pioneering discovery of alpha clustering and of molecular resonances, the field of nuclear clustering is today one of those domains of heavy-ion nuclear physics that faces the greatest challenges, yet also contains the greatest opportunities. After many summer schools and workshops, in particular over the last decade, the community of nuclear molecular physicists has decided to collaborate in producing a comprehensive collection of lectures and tutorial reviews covering the field. This third volume follows the successful Lect. Notes Phys. 818 (Vol. 1) and 848 (Vol. 2), and comprises six extensive lectures covering the following topics:  - Gamma Rays and Molecular Structure - Faddeev Equation Approach for Three Cluster Nuclear Reactions - Tomography of the Cluster Structure of Light Nuclei Via Relativistic Dissociation - Clustering Effects Within the Dinuclear Model : From Light to Hyper-heavy Molecules in Dynamical Mean-field Approach - Clusterization in Ternary Fission - Clusters in Light N...

  19. Spatial cluster modelling

    CERN Document Server

    Lawson, Andrew B

    2002-01-01

    Research has generated a number of advances in methods for spatial cluster modelling in recent years, particularly in the area of Bayesian cluster modelling. Along with these advances has come an explosion of interest in the potential applications of this work, especially in epidemiology and genome research. In one integrated volume, this book reviews the state-of-the-art in spatial clustering and spatial cluster modelling, bringing together research and applications previously scattered throughout the literature. It begins with an overview of the field, then presents a series of chapters that illuminate the nature and purpose of cluster modelling within different application areas, including astrophysics, epidemiology, ecology, and imaging. The focus then shifts to methods, with discussions on point and object process modelling, perfect sampling of cluster processes, partitioning in space and space-time, spatial and spatio-temporal process modelling, nonparametric methods for clustering, and spatio-temporal ...

  20. Unconventional methods for clustering

    Science.gov (United States)

    Kotyrba, Martin

    2016-06-01

    Cluster analysis or clustering is a task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). It is the main task of exploratory data mining and a common technique for statistical data analysis used in many fields, including machine learning, pattern recognition, image analysis, information retrieval, and bioinformatics. The topic of this paper is one of the modern methods of clustering namely SOM (Self Organising Map). The paper describes the theory needed to understand the principle of clustering and descriptions of algorithm used with clustering in our experiments.

  1. Cluster randomized clinical trials in orthodontics: design, analysis and reporting issues.

    Science.gov (United States)

    Pandis, Nikolaos; Walsh, Tanya; Polychronopoulou, Argy; Eliades, Theodore

    2013-10-01

    Cluster randomized trials (CRTs) use as the unit of randomization clusters, which are usually defined as a collection of individuals sharing some common characteristics. Common examples of clusters include entire dental practices, hospitals, schools, school classes, villages, and towns. Additionally, several measurements (repeated measurements) taken on the same individual at different time points are also considered to be clusters. In dentistry, CRTs are applicable as patients may be treated as clusters containing several individual teeth. CRTs require certain methodological procedures during sample calculation, randomization, data analysis, and reporting, which are often ignored in dental research publications. In general, due to similarity of the observations within clusters, each individual within a cluster provides less information compared with an individual in a non-clustered trial. Therefore, clustered designs require larger sample sizes compared with non-clustered randomized designs, and special statistical analyses that account for the fact that observations within clusters are correlated. It is the purpose of this article to highlight with relevant examples the important methodological characteristics of cluster randomized designs as they may be applied in orthodontics and to explain the problems that may arise if clustered observations are erroneously treated and analysed as independent (non-clustered).

  2. CLEAN: CLustering Enrichment ANalysis

    Directory of Open Access Journals (Sweden)

    Medvedovic Mario

    2009-07-01

    Full Text Available Abstract Background Integration of biological knowledge encoded in various lists of functionally related genes has become one of the most important aspects of analyzing genome-wide functional genomics data. In the context of cluster analysis, functional coherence of clusters established through such analyses have been used to identify biologically meaningful clusters, compare clustering algorithms and identify biological pathways associated with the biological process under investigation. Results We developed a computational framework for analytically and visually integrating knowledge-based functional categories with the cluster analysis of genomics data. The framework is based on the simple, conceptually appealing, and biologically interpretable gene-specific functional coherence score (CLEAN score. The score is derived by correlating the clustering structure as a whole with functional categories of interest. We directly demonstrate that integrating biological knowledge in this way improves the reproducibility of conclusions derived from cluster analysis. The CLEAN score differentiates between the levels of functional coherence for genes within the same cluster based on their membership in enriched functional categories. We show that this aspect results in higher reproducibility across independent datasets and produces more informative genes for distinguishing different sample types than the scores based on the traditional cluster-wide analysis. We also demonstrate the utility of the CLEAN framework in comparing clusterings produced by different algorithms. CLEAN was implemented as an add-on R package and can be downloaded at http://Clusteranalysis.org. The package integrates routines for calculating gene specific functional coherence scores and the open source interactive Java-based viewer Functional TreeView (FTreeView. Conclusion Our results indicate that using the gene-specific functional coherence score improves the reproducibility of the

  3. Survey on Text Document Clustering

    OpenAIRE

    M.Thangamani; Dr.P.Thangaraj

    2010-01-01

    Document clustering is also referred as text clustering, and its concept is merely equal to data clustering. It is hardly difficult to find the selective information from an ‘N’number of series information, so that document clustering came into picture. Basically cluster means a group of similar data, document clustering means segregating the data into different groups of similar data. Clustering can be of mathematical, statistical or numerical domain. Clustering is a fundamental data analysi...

  4. Metabolism and thermoregulation of individual and clustered long ...

    African Journals Online (AJOL)

    metabolism were measured for euthermiC bats at air temperatures higher than those available to them in their natural roost in summer, ... ported to the laboratory In a cloth bag. ... was passed through a Carbosorb/silica gel tube to absorb car-.

  5. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and

  6. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and mea

  7. Agricultural Clusters in the Netherlands

    NARCIS (Netherlands)

    Schouten, M.A.; Heijman, W.J.M.

    2012-01-01

    Michael Porter was the first to use the term cluster in an economic context. He introduced the term in The Competitive Advantage of Nations (1990). The term cluster is also known as business cluster, industry cluster, competitive cluster or Porterian cluster. This article aims at determining and mea

  8. Advanced nanostructured materials and their application for improvement of sun-light harvesting and efficiency of solar cells

    Science.gov (United States)

    Dimova-Malinovska, D.

    2016-02-01

    This review describes the application of different nanostructured materials in solar cells technology for improvement of sun-light harvesting and their efficiency. Several approaches have recently been proposed to increase the efficiency of solar cells above the theoretical limit which are based on a “photon management” concept that employs such phenomena as: (i) down-conversion, and (ii) surface plasmon resonance effect (iii) decreasing of the loss due to the reflection of the radiation, (iv) increasing of the reflection from the back contact, v) increasing of the effective solar cells surface, etc. The results demonstrate the possibility for to increasing of light harvesting, short circuit current and efficiency by application of nanomaterials in thin film and hetero-junction (HJ) solar cells. The first promising results allow an expectation for application of advanced nanomaterials in the 3d generation solar cells.

  9. Flexible N-doped TiO2/C ultrafine fiber mat and its photocatalytic activity under simulated sunlight

    Science.gov (United States)

    Wu, Nan; Wang, Yingde; Lei, Yongpeng; Wang, Bing; Han, Cheng

    2014-11-01

    Flexible N-doped TiO2/C ultrafine fiber (NTCf) mat has been produced via electrospinning and subsequent heat treatment, analyzed by a combination of characterizations. The nitrogen content can be modulated by the addition of urea. The composite fiber with mean diameter of around 500 nm exhibits outstanding mechanical flexibility. The TiO2 in the fiber obtained at 700 °C is anatase with a mass ratio of 23 wt%. In the photodegradation experiment under simulated sunlight, the as-prepared flexible mat demonstrates remarkable efficiency in the degradation of methylene blue (MB) due to the well-proportioned distribution of TiO2 nanoparticles and the improvement of charge transfer process. The nitrogen species in TiO2 lattice and the nitrogen functional groups on the surface of the fiber play crucial impacts on the photocatalytic activity.

  10. Green synthesis of silver nanoparticles using Carica Papaya fruit extract under sunlight irradiation and their colorimetric detection of mercury ions

    Science.gov (United States)

    Firdaus, M.; Andriana, S.; Elvinawati; Alwi, W.; Swistoro, E.; Ruyani, A.; Sundaryono, A.

    2017-04-01

    We have successfully synthesized silver nanoparticles (AgNPs) by using aqueous extract of papaya (Carica papaya) fruit as bioreductant under sunlight irradiation without additional capping agent. Characterizations were done using UV-Visible spectrophotometry and Fourier Transform Infrared Spectroscopy (FTIR). The synthesized AgNPs have yellowish-brown color with surface plasmon resonance peak at 410 nm. Good selectivity of the AgNPs towards hazardous heavy metal of mercury ions in aqueous solution has been developed as a green environmental sensor. The presence of Hg(II) ions in the mixture changed the yellowish-brown color of AgNPs to colorless due to oxidation of Ag(O) in AgNPs to Ag(I) ions. Effect of samples matrix such as alkali metal, alkaline earth metal and transition metal ions were evaluated.

  11. Sunlight to hydrogen conversion: Design optimization and energy management of concentrated photovoltaic (CPV-Hydrogen) system using micro genetic algorithm

    KAUST Repository

    Burhan, Muhammad

    2016-02-14

    Owing to the intermittent solar irradiance from cloud cover in the diurnal period and unavailability at night time, the practical design of a solar system requires energy backup storage for an uninterrupted supply or for off-grid operation. However, for highly efficient CPV (concentrated photovoltaic) system, the literature is lacking for energy management and optimization algorithm and tool for standalone operation. In this paper, a system with CPV and electrolyser is presented where beam irradiance of sunlight is harnessed to convert the instantaneously generated electricity into useful Hydrogen/Oxygen gas, where they can be stored and re-used for downstream applications such as the fuel cells, etc. The multi-variable design and multi-objective optimization strategies are proposed and presented for a standalone operation of the CPV-Hydrogen system as well as their system performances, particularly electrical rating of CPV based upon the real weather data of Singapore. © 2016 Elsevier Ltd.

  12. Retrieving the vertical distribution of stratospheric OClO from Odin/OSIRIS limb-scattered sunlight measurements

    Directory of Open Access Journals (Sweden)

    P. Krecl

    2005-05-01

    Full Text Available The first vertical profiles of stratospheric OClO retrieved from Odin/OSIRIS limb-scattered sunlight radiances are presented. The retrieval method is based on a two-step approach, using differential optical absorption spectroscopy combined with the maximum a posteriori estimator. The details of the spectral window selection, spectral corrections and inversion technique are discussed. The results show that OClO can be detected inside the South polar vortex region between about 12 and 20 km altitude with a 2–5 km height resolution and an estimated retrieval error better than 60% at the peak. OClO concentrations are consistent with chemical transport model simulations and show the expected relation to the atmospheric conditions in the lower stratosphere in the austral spring 2002. This unique data set of OClO profiles is very promising to study the stratospheric chlorine activation in both polar regions.

  13. Retrieving the vertical distribution of stratospheric OClO from Odin/OSIRIS limb-scattered sunlight measurements

    Directory of Open Access Journals (Sweden)

    P. Krecl

    2006-01-01

    Full Text Available The first vertical profiles of stratospheric OClO retrieved from Odin/OSIRIS limb-scattered sunlight radiances are presented. The retrieval method is based on a two-step approach, using differential optical absorption spectroscopy combined with the maximum a posteriori estimator. The details of the spectral window selection, spectral corrections and inversion technique are discussed. The results show that OClO can be detected inside the South polar vortex region between about 14 and 22 km altitude with a 2–5 km height resolution and an estimated retrieval error better than 50% at the peak. OClO concentrations show the expected relation to the atmospheric conditions in the lower stratosphere in the austral spring 2002. This unique data set of OClO profiles is very promising to study the stratospheric chlorine activation in both polar regions.

  14. Asteroid thermal modeling in the presence of reflected sunlight with an application to WISE/NEOWISE observational data

    CERN Document Server

    Myhrvold, Nathan

    2016-01-01

    This study addresses thermal modeling of asteroids with a new derivation of the Near Earth Asteroid Thermal (NEATM) model which correctly accounts for the presence of reflected sunlight in short wave IR bands. Kirchhoff's law of thermal radiation applies to this case and has important implications. New insight is provided into the eta parameter in the NEATM model and it is extended to thermal models besides NEATM. The role of surface material properties on eta is examined using laboratory spectra of meteorites and other asteroid compositional proxies; the common assumption that emissivity e=0.9 in asteroid thermal models may not be justified and can lead to misestimating physical parameters. In addition, indeterminacy in thermal modeling can limit its ability to uniquely determine temperature and other physical properties. A new curve fitting approach allows thermal modeling to be done independent of visible band observational parameters such as the absolute magnitude H. These new thermal modeling techniques ...

  15. Using ocean-glint scattered sunlight as a diagnostic tool for satellite remote sensing of greenhouse gases

    Directory of Open Access Journals (Sweden)

    A. Butz

    2013-09-01

    Full Text Available Spectroscopic measurements of sunlight backscattered by the Earth's surface is a technique widely used for remote sensing of atmospheric constituent concentrations from space. Thereby, remote sensing of greenhouse gases poses particularly challenging accuracy requirements for instrumentation and retrieval algorithms which, in general, suffer from various error sources. Here, we investigate a method that helps disentangle sources of error for observations of sunlight backscattered from the glint spot on the ocean surface. The method exploits the backscattering characteristics of the ocean surface, which is bright for glint geometry but dark for off-glint angles. This property allows for identifying a set of clean scenes where light scattering due to particles in the atmosphere is negligible such that uncertain knowledge of the lightpath can be excluded as a source of error. We apply the method to more than 3 yr of ocean-glint measurements by the Thermal And Near infrared Sensor for carbon Observation (TANSO Fourier Transform Spectrometer (FTS onboard the Greenhouse Gases Observing Satellite (GOSAT, which aims at measuring carbon dioxide (CO2 and methane (CH4 concentrations. The proposed method is able to clearly monitor recent improvements in the instrument calibration of the oxygen (O2 A-band channel and suggests some residual uncertainty in our knowledge about the instrument. We further assess the consistency of CO2 retrievals from several absorption bands between 6400 cm−1 (1565 nm and 4800 cm−1 (2100 nm and find that the absorption bands commonly used for monitoring of CO2 dry air mole fractions from GOSAT allow for consistency better than 1.5 ppm. Usage of other bands reveals significant inconsistency among retrieved CO2 concentrations pointing at inconsistency of spectroscopic parameters.

  16. Influence of manure age and sunlight on the community structure of cattle fecal bacteria as revealed by Illumina sequencing

    Science.gov (United States)

    Wong, K.; Shaw, T. I.; Oladeinde, A.; Molina, M.

    2013-12-01

    Fecal pollution of environmental waters is a major concern for the general public because exposure to fecal-associated pathogens can have severe impacts on human health. Stream and river impairment due to fecal pollution is largely the result of agricultural activities in the United States. In the last few years, numerous metagenomic studies utilized next generation sequencing to develop microbial community profiles by massively sequencing the 16sRNA hypervariable region. This technology supports the application of water quality assessment such as pathogen detection and fecal source tracking. The bacteria communities of samples in these studies were determined when they were freshly collected; therefore, little is known about how feces age or how environmental stress influences the microbial ecology of fecal materials. In this study we monitored bacteria community changes in cattle feces for 57 days after excretion (day 0, 2, 4 8, 15, 22, 29, 43, 57) by sequencing the 16s variable region 4, using Illumnia MiSeq. Twelve cattle feces were studied; half of the samples were directly exposed to sunlight (unshaded) and half were shaded. Results indicate that the relative abundance (RA) profile in both shaded and unshaded samples rapidly changed from day 0 to 15, but stabilized from day 22 to 57. Firmcutes were the most abundant phylum (~40%) at day 0, but were reduced to bacteria community in the natural environment. According to the rarefaction curve analysis, richness of bacteria diversity in feces decreased as time progressed. Some pathogens such as Campylobacter were detected only at the beginning, meaning they substantially decayed during the course of our study. Overall, this study indicated: (1) sunlight can influence the community structure and (2) after excretion the fecal bacteria diversity can be significantly changed over time. Future studies should therefore use not only the microbial signature of fresh but also moderately aged fecal samples to develop more

  17. Mesoporous film of WO3-the "sunlight" assisted decomposition of surfactant in wastewater for voltammetric determination of Pb

    Science.gov (United States)

    Krasnodębska-Ostręga, Beata; Bielecka, Agnieszka; Biaduń, Ewa; Miecznikowski, Krzysztof

    2016-12-01

    In this paper we present the application of "sunlight" assisted digestion in the presence of WO3 to the decomposition of dissolved organic matter, using the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant (1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol (Triton™X-114) in natural water samples, prior to the determination of traces residues of lead by stripping voltammetry methods. The results of the study showed firstly that the preparation of reproducible WO3 layers characterized by high mechanical and chemical resistance was possible, and secondly that it was also possible to obtain a high efficiency of decomposition, equal in efficiency to that of the reference method, which was the hydrogen peroxide oxidation assisted by UV, with evaporation nearly to dryness. The developed procedure is suggested to be a no-reagents method for the decomposition of added SDS, leading to 100% recovery of added Pb (II). The anodic stripping voltammetric curves recorded in solution after 4 h irradiation with UV assisted by WO3 were repeatable and increased linearly with standard additions, but the data finally obtained were incorrect. The curves recorded in solution after "sunlight" assisted digestion in the presence of WO3 were repeatable, and increased linearly with an increasing of concentration of standard additions (100% recovery of Pb). In the case of a nonionic surfactant, the decomposition time is at least 6 h. The advantage of the proposed method is the fact that the digestion process does not need the addition of any chemicals for the complete decomposition of organic matter.

  18. Synthesis, Characterization, and Sunlight Mediated Photocatalytic Activity of CuO Coated ZnO for the Removal of Nitrophenols.

    Science.gov (United States)

    Qamar, M Tariq; Aslam, M; Ismail, Iqbal M I; Salah, Numan; Hameed, A

    2015-04-29

    CuO@ZnO core-shell catalysts, coated by varying the CuO layer density ranging from 0.5% to 10%, were synthesized with the aim to enhance the photocatalytic activity of ZnO in sunlight and control its photocorrosion. Initially, the Cu(2+) ions were impregnated on presynthesized ZnO by wet impregnation and finally converted to CuO layers by calcination. The optical and structural characterization of the synthesized powders was performed by DRS, PL, Raman spectroscopy, and XRD analysis, respectively. The homogeneity of the coated layers was explored by FESEM. The photocatalytic activity of CuO coated ZnO was investigated for the degradation of mononitrophenols (2-, 3-, and 4-nitrophenol) and dinitrophenols (2,4-, 2,5-, and 2,6-dinitrophenol) in the exposure of the complete spectrum and visible region (420-800 nm) of sunlight. The effect of the increasing density coated layers of CuO on photocatalytic activity was evaluated for the degradation of 4-NP. Compared to pristine ZnO, a substantial increase in the degradation/mineralization ability was observable for the catalysts coated with 0.5% and 1% CuO, whereas a detrimental effect was noticed for higher coating density. Prior to photocatalytic studies, as evaluated by cyclic voltammetry (CV), compared to pure ZnO, a significant suppression of photocorrosion was noticed, under illumination, for catalysts coated with lower CuO coating. The progress of the photocatalytic degradation process was monitored by HPLC while the mineralization ability of the synthesized catalysts was estimated by TOC. The estimation of the released ions and their further interaction with the excited states and the reactive oxygen was monitored by ion chromatography (IC).

  19. Using ocean-glint scattered sunlight as a diagnostic tool for satellite remote sensing of greenhouse gases

    Directory of Open Access Journals (Sweden)

    A. Butz

    2013-05-01

    Full Text Available Spectroscopic measurements of sunlight backscattered by the Earth's surface is a technique widely used for remote sensing of atmospheric constituent concentrations from space. Thereby, remote sensing of greenhouse gases poses particularly challenging accuracy requirements for instrumentation and retrieval algorithms which, in general, suffer from various error sources. Here, we investigate a method that helps disentangle sources of error for observations of sunlight backscattered from the glint spot on the ocean surface. The method exploits the backscattering characteristics of the ocean surface which is bright for glint geometry but dark for off-glint angles. This property allows for identifying a set of clean scenes where light scattering due to particles in the atmosphere is negligible such that uncertain knowledge of the lightpath can be excluded as a source of error. We apply the method to more than 3 yr of ocean-glint measurements by the Thermal And Near infrared Sensor for carbon Observation (TANSO – Fourier Transform Spectrometer (FTS onboard the Greenhouse Gases Observing Satellite (GOSAT which aims at measuring carbon dioxide (CO2 and methane (CH4 concentrations. The proposed method is able to clearly monitor recent improvements in the instrument calibration of the oxygen (O2 A-band channel and suggests some residual uncertainty in our knowledge about the instrument. We further assess the consistency of CO2 retrievals from several absorption bands between 6400 cm−1 (1565 nm and 4800 cm−1 (2100 nm and find that the absorption bands commonly used for monitoring of CO2 dry air mole fractions from GOSAT allow for consistency better than 1.5 ppm. Usage of other bands reveals significant inconsistency among retrieved CO2 concentrations pointing at inconsistency of spectroscopic parameters.

  20. OPEN CLUSTERS AS PROBES OF THE GALACTIC MAGNETIC FIELD. I. CLUSTER PROPERTIES

    Energy Technology Data Exchange (ETDEWEB)

    Hoq, Sadia; Clemens, D. P., E-mail: shoq@bu.edu, E-mail: clemens@bu.edu [Institute for Astrophysical Research, 725 Commonwealth Avenue, Boston University, Boston, MA 02215 (United States)

    2015-10-15

    Stars in open clusters are powerful probes of the intervening Galactic magnetic field via background starlight polarimetry because they provide constraints on the magnetic field distances. We use 2MASS photometric data for a sample of 31 clusters in the outer Galaxy for which near-IR polarimetric data were obtained to determine the cluster distances, ages, and reddenings via fitting theoretical isochrones to cluster color–magnitude diagrams. The fitting approach uses an objective χ{sup 2} minimization technique to derive the cluster properties and their uncertainties. We found the ages, distances, and reddenings for 24 of the clusters, and the distances and reddenings for 6 additional clusters that were either sparse or faint in the near-IR. The derived ranges of log(age), distance, and E(B−V) were 7.25–9.63, ∼670–6160 pc, and 0.02–1.46 mag, respectively. The distance uncertainties ranged from ∼8% to 20%. The derived parameters were compared to previous studies, and most cluster parameters agree within our uncertainties. To test the accuracy of the fitting technique, synthetic clusters with 50, 100, or 200 cluster members and a wide range of ages were fit. These tests recovered the input parameters within their uncertainties for more than 90% of the individual synthetic cluster parameters. These results indicate that the fitting technique likely provides reliable estimates of cluster properties. The distances derived will be used in an upcoming study of the Galactic magnetic field in the outer Galaxy.