277 research outputs found

    Time-resolved spectroscopy of the pulsating CV GW Lib

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    We present time-resolved optical spectroscopy of the dwarf nova GW Librae during its rare 2007 April superoutburst and compare these with quiescent epochs. The data provide the first opportunity to track the evolution of the principal spectral features. In the early stages of the outburst, the optically thick disc dominates the optical and the line components show clear orbital radial velocity excursions. In the course of several weeks, optically thin regions become more prominent as strong emission lines replace the broad disc absorption. Post-outburst spectroscopy covering the I band illustrates the advantages of Ca II relative to the commonly used Balmer lines when attempting to constrain binary parameters. Due to the lower ionization energy combined with smaller thermal and shear broadening of these lines, a sharp emission component is seen to be moving in between the accretion disc peaks in the Ca II line. No such component is visible in the Balmer lines. We interpret this as an emission component originating on the hitherto unseen mass donor star. This emission component has a mean velocity of similar to -15 +/- 5 km s(-1) which is associated with the systemic velocity., and a velocity semi-amplitude of K-em = 82.2 +/- 4.9 km s(-1). Doppler tomography reveals an asymmetric accretion disc, with the S-wave mapping to a sharp spot in the tomogram with a velocity consistent to what is obtained with line profile fitting. A centre of symmetry analysis of the disc component suggests a very small value for the WD orbital velocity K-1 as is also inferred from double Gaussian fits to the spectral lines. While our conservative dynamical limits place a hard upper limit on the binary mass ratio of q < 0.23, we favour a significantly lower value near q similar to 0.06. Pulsation modelling suggests a white dwarf mass similar to 1 M-circle dot. This, paired with a low-mass donor, near the empirical sequence of an evolved cataclysmic variable close to the period bounce, appears to be consistent with all the observational constraints to date

    Switching health insurers: the role of price, quality and consumer information search

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    __Abstract__ We examine the impact of price, service quality and information search on people’s propensity to switch health insurers in the competitive Dutch health insurance market. Using panel data from annual household surveys and data on health insurers’ premiums and quality ratings over the period 2006–2012, we estimate a random effects logit model of people’s switching decisions. We find that switching propensities depend on health plan price and quality, and on people’s age, health, education and having supplementary or group insurance. Young people (18–35 years) are more sensitive to price, whereas older people are more sensitive to quality. Searching for health plan information has a much stronger impact on peoples’ sensitivity to price than to service quality. In addition, searching for health plan information has a stronger impact on the switching propensity of higher than lower educated people, suggesting that higher educated people make better use of available health plan information. Finally, having supplementary insurance significantly reduces older people’s switching propensity

    Optimal Development of Youth Athletes Toward Elite Athletic Performance: How to Coach Their Motivation, Plan Exercise Training, and Pace the Race

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    Elite athletes have invested many years in training and competition to reach the elite level. One very important factor on the road to elite performance is the decision-making process regarding the regulation of effort over time, termed as pacing behavior. The regulation of effort is vital for optimal athletic performance during a single race and over a longer period of time (e.g., a competitive season) as an inadequate regulation could result in a higher risk of injuries, overtraining, and drop-out. Despite this, there is limited knowledge on how young athletes learn and develop the abilities related to pacing. Pacing behavior of athletes develops from childhood throughout adolescence and is thought to be closely connected to physical maturation, the development of pre-frontal cortical related (meta-) cognitive functions, as well as the gathering of experience with exercise tasks. The motivation of an athlete can critically influence how an athlete paces a single race, but also how they distribute their effort over a longer period of time. Coaches are advised to closely monitor the development of pacing behavior during adolescence (e.g., by gathering split times, and related physiological measurement, during training and competition), as well as the underlying factors including physical maturation (meta-) cognitive development and the motivation of young athletes. Furthermore, pacing behavior development could be aided by providing training in which the task, individual, and environment are manipulated. Hereby, presenting athletes with the opportunity to gain experience in situations which closely resemble the perceptual-motor conditions of upcoming competitions

    Trajectories of Adolescents Treated with Gonadotropin-Releasing Hormone Analogues for Gender Dysphoria

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    Gonadotropin-releasing hormone analogues (GnRHa) are recommended as initial treatment for adolescents diagnosed with gender dysphoria, providing time to follow gender identity development and consider further treatment wishes without distress caused by unwant

    Pregnancy Profile and Infant Outcomes Among HIV Infected Women Who Delivered in Cipto Mangunkusumo Hospital

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    Background: HIV infection in pregnancy is a big concern for the future of our nation. The virus can be transmitted to the baby through pregnancy, childbirth and during breastfeeding which rendering to early detection and intervention. The aim of this study was to describe the transmission prevention cascade among our patient. Methods: this was a retrospective cohort study of HIV vertical transmission. The inclusion criteria was pregnant women with HIV infection who have antenatal care in Cipto Mangunkusumo Hospital from January 2013 up to December 2018. Data was retrieved from medical record, HIV registry and laboratory results. The included data were demographic, risk of infection, obstetrical data, mode of delivery, ARV history, laboratory history in mother and infant. Data was presented as descriptive. Results: there was 138 HIV pregnant women included as study subjects. Most women were at 25-29 years old (39.85%), as housewife (41.30%), with history of more than one sexual partners (50.73%). The subjects was mostly multigravida (77.5%), first visit to RSCM in third trimester (98.6%), with history of antenatal care >4 times (48.6%), singleton fetus (99.3%), and delivered by C-section (84.1%). HIV diagnosis was done during pregnancy (73.53%), and already on antiretroviral (ARV) for more than 6 months (50.7%). There was 78% subjects with CD4 (24% subjects with 200 copies/uL). Around 72.5% infants born with birth weight 2500-3500g. Almost all infant received ARV prophylaxis (97.9%) and formula feeding. PCR HIV was examined on 16 infant on 6 weeks of age and and 13 on 6 month age. There was 1 infant with viral load results >400 copies/ml which immediately refered to Pediatric HIV clinic. Bivariate analysis showed significant correlation between maternal ARV consumption and infant result at birth (P=0.05). Maternal CD4 level was not significantly correlate with neonatal virology status (P=0.12). Conclusion:HIV diagnosis in pregnant women is important, since ARV administration on early pregnancy significantly reduce vertical transmission. ARV prophylaxis protocols is important to prevent HIV infection on infant.

    Mixing of mineral dust with urban pollution aerosol over Dakar (Senegal): Impact on dust physico-chemical and radiative properties.

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    In the framework of the Saharan Mineral Dust Experiment (SAMUM) in 2008, the mixing of the urban pollution plume of Dakar (Senegal) with mineral dust was studied in detail using the German research aircraft Falcon which was equipped with a nadir-looking high spectral resolution lidar (HSRL) and extensive aerosol in situ instrumentation. The mineral dust layer as well as the urban pollution plume were probed remotely by the HSRL and in situ. Back trajectory analyses were used to attribute aerosol samples to source regions.We found that the emission from the region of Dakar increased the aerosol optical depth (532 nm) from approximately 0.30 over sea and over land east of Dakar to 0.35 in the city outflow. In the urban area, local black carbon (BC) emissions, or soot respectively, contributed more than 75% to aerosol absorption at 530 nm. In the dust layer, the single-scattering albedo at 530 nm was 0.96 â�� 0.99, whereas we found a value of 0.908 �± 0.018 for the aerosol dominated by urban pollution. After 6h of transport over the North Atlantic, the externally mixed mode of secondary aerosol particles had almost completely vanished, whereas the BC agglomerates (soot) were still externally mixed with mineral dust particles

    Smoke and Alcohol Free with EHealth and Rewards (SAFER) pregnancy study:a before-after study protocol

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    Despite existing interventions, tobacco smoking and alcohol consumption during pregnancy are common. The Smoke and Alcohol Free with EHealth and Rewards (SAFER) pregnancy intervention combines monthly group sessions, access to a web-based platform and incentives upon biochemically validated cessation for a maximum duration of 6 months to promote cessation of smoking and alcohol use before and during pregnancy. To inform development of the SAFER pregnancy intervention, two focus groups with the target population were held beforehand, with results reported here alongside the final SAFER pregnancy study protocol. In a before-after study we aim to include 66 women who are pregnant or have a wish to become pregnant and who smoke and/or consume alcohol (i.e. target population of the SAFER pregnancy intervention). The primary outcome measure is cessation of smoking and/or alcohol use at 34-38 weeks of gestation, or after six group sessions if women did not become pregnant during the study period. Secondary outcomes focus on the barriers and facilitators for implementation of the SAFER pregnancy intervention

    Reflecting photonics: reaching new audiences through new partnerships – IYL 2015 and the Royal Horticultural Society Flower Show

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    The ‘Reflecting Photonics’ show garden was exhibited at the 2015 Royal Horticultural Society (RHS) Flower Show in Tatton Park, UK, to celebrate the International Year of Light and Light-based Technologies. Elks-Smith Garden Design alongside landscapers ‘Turf N’ Earth’ collaborated with researchers, marketing and outreach professionals from the University of Southampton to design, construct and exhibit a photonics-themed garden. The garden and supporting exhibition united science and art to reach new audiences – particularly family groups alongside other key influencers to the young – and showcased the world-leading research in optical fibers at the university in an accessible manner. Researchers and a publicity professional, funded by the EPSRC Centre for Innovative Manufacturing in Photonics, developed an integrated approach to the event’s public engagement and marketing. The overarching aim was to influence a positive change in the attitude of the garden visitors towards physics and photonics, with additional focus on promoting careers for women in STEM. The show garden won an RHS Gold Medal award and the coveted ‘People’s Choice Award’ for the best large garden. The project subsequently won the South East England Physics Network Public Engagement Innovation Project Award. Approximately 80,000 visitors saw the garden, with a further three million television viewers on a popular British gardening show. There were also over 75,400 Tweet impressions on social media. This paper discusses the project aims, explores the design of the garden and its relationship with the research, describes the work of the public engagement team, and outlines the impact of the event

    Airborne observations of the Eyjafjalla volcano ash cloud over Europe during air space closure in April and May 2010

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    © Author(s) 2011. This work is distributed under the Creative Commons Attribution 3.0 LicenseAirborne lidar and in-situ measurements of aerosols and trace gases were performed in volcanic ash plumes over Europe between Southern Germany and Iceland with the Falcon aircraft during the eruption period of the Eyjafjalla1 volcano between 19 April and 18 May 2010. Flight planning and measurement analyses were supported by a refined Meteosat ash product and trajectory model analysis. The volcanic ash plume was observed with lidar directly over the volcano and up to a distance of 2700 km downwind, and up to 120 h plume ages. Aged ash layers were between a few 100 m to 3 km deep, occurred between 1 and 7 km altitude, and were typically 100 to 300 km wide. Particles collected by impactors had diameters up to 20 μm diameter, with size and age dependent composition. Ash mass concentrations were derived from optical particle spectrometers for a particle density of 2.6 g cm-3 and various values of the refractive index (RI, real part: 1.59; 3 values for the imaginary part: 0, 0.004 and 0.008). The mass concentrations, effective diameters and related optical properties were compared with ground-based lidar observations. Theoretical considerations of particle sedimentation constrain the particle diameters to those obtained for the lower RI values. The ash mass concentration results have an uncertainty of a factor of two. The maximum ash mass concentration encountered during the 17 flights with 34 ash plume penetrations was below 1 mg m-3. The Falcon flew in ash clouds up to about 0.8 mg m-3 for a few minutes and in an ash cloud with approximately 0.2 mg -3 mean-concentration for about one hour without engine damage. The ash plumes were rather dry and correlated with considerable CO and SO2 increases and O3 decreases. To first order, ash concentration and SO2 mixing ratio in the plumes decreased by a factor of two within less than a day. In fresh plumes, the SO2 and CO concentration increases were correlated with the ash mass concentration. The ash plumes were often visible slantwise as faint dark layers, even for concentrations below 0.1 mg m-3. The large abundance of volatile Aitken mode particles suggests previous nucleation of sulfuric acid droplets. The effective diameters range between 0.2 and 3 μm with considerable surface and volume contributions from the Aitken and coarse mode aerosol, respectively. The distal ash mass flux on 2 May was of the order of 500 (240-1600) kgs -1. The volcano induced about 10 (2.5-50) Tg of distal ash mass and about 3 (0.6-23) Tg of SO2 during the whole eruption period. The results of the Falcon flights were used to support the responsible agencies in their decisions concerning air traffic in the presence of volcanic ash.Peer reviewe
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