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Carbon-14 (radiocarbon, 14C) is a long-lived radionuclide (5730 yr) of interest regarding the safety for the management of intermediate level wastes (ILW). The present study gives an overview of the release of 14C from irradiated Zircaloy cladding in alkaline media. 14C is found either in the alloy part of Zircaloy cladding due to the neutron activation of 14N impurities by 14N(n,p)14C reaction, or in the oxide layer (ZrO2) formed at the metal surface by the neutron activation of 17O from UO2 or (U-Pu)O2 fuel and water from the primary circuit in the reactor by 17O(n,α)14C reaction. Various irradiated and unirradiated Zircaloys have been studied. The total 14C inventory has been determined both experimentally and by calculations. The results seem to be in good agreement. Leaching experiments were conducted in alkaline media for several time durations. 14C was mainly released as carboxylic acids. Further, corrosion measurements were performed by using both hydrogen measurements and electrochemical measurements. The corrosion rate (CR) ranges from a few nm/yr to 100 nm/yr depending on the surface conditions and the method used for measurement. From a safety assessment point of view, the instant release fraction (IRF) was determined on irradiated Zircaloy-2. The results showed that the 14C inventory in the oxide was significantly below the 20% commonly used in safety case assessments.
The Neolithic transition is a particularly favorable field of research for the study of the emergence and evolution of cultures and cultural phenomena. In this framework, high-precision chronologies are essential for decrypting the rhythms of emergence of new techno-economic traits. As part of a project exploring the conditions underlying the emergence and dynamics of the development of the first agro-pastoral societies in the Western Mediterranean, this paper proposes a new chronological modeling. Based on 45 new radiocarbon (14C) dates and on a Bayesian statistical framework, this work examines the rhythms and dispersal paths of the Neolithic economy both on coastal and continental areas. These new data highlight a complex and far less unidirectional dissemination process than that envisaged so far.
The patient portal may be an effective method for administering surveys regarding participant research experiences but has not been systematically studied.
We evaluated 4 methods of delivering a research participant perception survey: mailing, phone, email, and patient portal. Participants of research studies were identified (n=4013) and 800 were randomly selected to receive a survey, 200 for each method. Outcomes included response rate, survey completeness, and cost.
Among those aged <65 years, response rates did not differ between mail, phone, and patient portal (22%, 29%, 30%, p>0.07). Among these methods, the patient portal was the lowest-cost option. Response rates were significantly lower using email (10%, p<0.01), the lowest-cost option. In contrast, among those aged 65+ years, mail was superior to the electronic methods (p<0.02).
The patient portal was among the most effective ways to reach research participants, and was less expensive than surveys administered by mail or telephone.
Prolonged conflict and economic instability challenge the existing support networks in families and society places significant stress on both adults and adolescents. Exploring individual, family and social factors that increase the likelihood of or protect adolescents from negative outcomes are important to the development of evidence-based prevention and response programing in global settings.
Examine the relationship between parent mental health and experience/perpetration of intimate partner violence (IPV) and adolescent behaviors, stigma, and school attendance. The relationship is further examined for differences by gender.
Secondary analysis of data from an ongoing comparative effectiveness trial of a productive asset transfer program in eastern Democratic Republic of Congo (DRC).
Three hundred and eighty-eight adolescent and parent dyads were included in the analysis. The analysis demonstrated that parent mental health and IPV can have a negative impact their children's well-being and the impact is different for boys and girls, likely linked to gender roles and responsibilities in the home and community. Social relationships of adolescents, as reported through experienced stigma, were negatively impacted for both boys and girls. Parent report of symptoms of PTSD and depression had a stronger negative effect on girls’ outcomes, including experienced stigma, externalizing behaviors, and missed days of school than boys. For adolescent boys, their parent's report of IPV victimization/perpetration was associated with more negative behaviors at the 8-month follow-up assessment.
The findings reinforce the critical importance of interventions that engage parents and their children in activities that advance health and improve relationships within the family.
A study was carried out, from 2012 to 2015, in 10 French départements to estimate the serological prevalence of Q fever and the frequency of abortive episodes potentially related to Coxiella burnetii in a large sample of cattle, sheep and goat herds. The serological survey covered 731 cattle, 522 sheep and 349 goat herds, randomly sampled. The frequency of abortive episodes potentially related to C. burnetii was estimated by investigating series of abortions in 2695 cattle, 658 sheep and 105 goat herds using quantitative polymerase chain reaction analyses and complementary serological results when needed. The average between-herd seroprevalence was significantly lower for cattle (36·0%) than for sheep (55·7%) and goats (61·0%) and significantly higher for dairy herds (64·9% for cattle and 75·6% for sheep) than for meat herds (18·9% for cattle and 39·8% for sheep). Within-herd seroprevalence was also significantly higher for goats (41·5%) than for cattle (22·2%) and sheep (25·7%). During the study period, we estimated that 2·7% (n = 90), 6·2% (n = 48) and 16·7% (n = 19) of the abortive episodes investigated could be ‘potentially related to C. burnetii’in cattle, sheep and goat herds, respectively. Overall, strong variability was observed between départements and species, suggesting that risk factors such as herd density and farming practices play a role in disease transmission and maintenance.
Objectives: Good glycemic control is an important goal of diabetes management. Late adolescents with type 1 diabetes (T1D) are at risk for poor glycemic control as they move into young adulthood. For a subset of these patients, this dysregulation is extreme, placing them at risk for life-threatening health complications and permanent cognitive declines. The present study examined whether deficiency in emotional decision making (as measured by the Iowa Gambling Task; IGT) among teens with T1D may represent a neurocognitive risk factor for subsequent glycemic dysregulation. Methods: As part of a larger longitudinal study, a total of 241 high-school seniors (147 females, 94 males) diagnosed with T1D underwent baseline assessment that included the IGT. Glycated hemoglobin (HbA1c), which reflects glycemic control over the course of the past 2 to 3 months, was also assessed at baseline. Of the 241,189 (127 females, 62 males, mean age=17.76, mean HbA1c=8.11) completed HbA1c measurement 1 year later. Results: Baseline IGT performance in the impaired range (per norms) was associated with greater dysregulation in glycemic control 1 year later, as evidenced by an average increase in HbA1c of 2%. Those with normal IGT scores (per norms) exhibited a more moderate increase in glycemic control, with an HbA1c increase of 0.7%. Several IGT scoring approaches were compared, showing that the total scores collapsed across all trials was most sensitive to change in glycemic control. Conclusions: IGT assessment offers promise as a tool for identifying late adolescents at increased risk for glycemic dysregulation. (JINS, 2017, 23, 204–213)
This study uses the eigenvalues of the local velocity gradient tensor to categorize the local flow structures in incompressible turbulent flows into different types of saddle nodes and vortices and investigates their effect on the local collision kernel of heavy particles. Direct numerical simulation (DNS) results show that most of the collisions occur in converging regions with real and negative eigenvalues. Those regions are associated not only with a stronger preferential clustering of particles, but also with a relatively higher collision kernel. To better understand the DNS results, a conceptual framework is developed to compute the collision kernel of individual flow structures. Converging regions, where two out of three eigenvalues are negative, posses a very high collision kernel, as long as a critical amount of rotation is not exceeded. Diverging regions, where two out of three eigenvalues are positive, have a very low collision kernel, which is governed by the third and negative eigenvalue. This model is not suited for particles with Stokes number
, where the contribution of particle collisions from caustics is dominant.
Massive evolved stars contribute to the chemical enrichment of the Galaxy. When they die as supernova but also through their mass loss during the several thousands of years of their red supergiant (RSG) phase. Unfortunately the mass loss mechanism remains poorly understood. Detailed study of the CSE and photosphere of nearby RSGs is required to constrain this scenario.
Betelgeuse is the closest RSG (197 pc) and therefore has a large apparent diameter (~ 42 mas) which makes it a very interesting target. For several years, our team has lead a multi-wavelength and multi-scale observing program to characterize its mass loss. We will review here our recent results in near-infrared interferometry.
The efficiency of thin-film solar cells using a-Si:H is limited by the decrease in a-Si:H layer optical path length and its poor light absorption at red and NIR wavelengths. Metal NP such as Au have been shown to increase the absorption in the active material and then cell performances, by exhibiting localized surface plasmon (LSP) resonances. Our work’s goal is to understand NP influence in such cells, to perform an optimal structure by increasing the amount of light absorbed within the cell using NP scattering and luminescence. Modeling based on Mie theory is first carried out using bulk Palik data for Au spheres with various diameters and refractive medium indexes. Using modeling parameters, Au layers were deposited on glass and SnO2 substrates respectively by thermal evaporation in vacuum and sputtering, followed by thermal annealing (200 ∼ 500°C) in order to promote the NP growth. MEB pictures show quasispherical Au NP shape with a mean size of 150nm. This diameter range switches extinction of NP in scattering regime. Annealing temperature (T) strongly affects the NP morphology. Surface coverage decreases and sphericity appears to increase with T. UV-Visible spectroscopy displays distinct LSP resonances around 600nm after annealing with a red shift while T increases.
Electroconvulsive therapy (ECT) is an effective treatment for depression but the extent and persistence of cognitive side-effects remain uncertain. It has been reported that there is little evidence that impairments last longer than up to 15 days post-ECT. However, relatively few studies have followed patients for even as long as 1 month post-ECT. Here we report results from a brief cognitive battery given prior to ECT and repeated five times up to 6 months post-ECT.
In a retrospective case-note study of routinely collected clinical data 126 patients treated with ECT completed two neuropsychological tests [Cambridge Neuropsychological Test Automated Battery (CANTAB) spatial recognition memory (SRM) and Mini Mental State Examination (MMSE)] and two subjective reports of memory function, prior to ECT. Patients were reassessed following ECT and at 1, 3 and 6 months post-ECT although not all patients completed all assessments.
Performance relative to pre-ECT baseline was significantly poorer at each post-ECT assessment up to 3 months post-ECT using the CANTAB SRM, but was improved at 6 months. Conversely, MMSE score showed improvements relative to baseline from 1 month post-ECT. Mood and subjective memory scores improved following ECT and were correlated with one another, but not with either neuropsychological measure.
The CANTAB SRM task revealed reversible cognitive deficiencies relative to a pre-ECT baseline for at least 3 months following ECT, while MMSE score and patients' subjective reports showed only improvement. Visuospatial memory scores eventually exceeded baseline 6 months post-ECT.
Scant research has examined health-related quality of life (HRQoL) in family members of patients with severe brain injury, even less has been done in Scandinavian countries, and none has examined this construct longitudinally. The current study therefore used multilevel modelling to investigate the trajectories of HRQoL in 94 Danish family members of patients with severe brain injury at five time points, beginning at the patient's stay in a neuro intensive care unit through one year after injury. The family members’ HRQoL scores significantly and strongly increased over time, and Role Limitations – Emotional scores were higher when patients had high Rancho Los Amigos Scale scores at admission to early intensive rehabilitation in hospital. These results suggest that the acute and sub-acute periods after brain injury are an extremely difficult time psychologically for many families, and family-based mental health interventions during the acute and sub-acute phases are critical, especially for families who have a patient with severe deficits.
We present new high-resolution observations and modeling of SSTtau J042021+ 281349, a 400 AU-radius edge-on protoplanetary disk. We have gathered visible and near-infrared scattered light images of the system with the Hubble Space Telescope and Keck adaptive optics system, as well as a 1.3 mm continuum map with CARMA. Compared to the well-known HH 30 disk, this new system is remarkable because of its spectacular bipolar jet and the high degree of lateral symmetry of the disk. Indeed, we argue that this system is a “cleaner” prototype for edge-on disks. In addition, the apparent achromaticity of dust properties (most notably the almost grey opacity law) from the visible to the near-infrared in this disk suggests that it is in an advanced stage of dust evolution.
The Archival Legacy Investigation of Circumstellar Environments (ALICE) project (AR-12652) is currently conducting a comprehensive and consistent reprocessing of HST-NICMOS coronagraphic survey data to search for point sources and disks using advanced PSF subtraction. The KLIP algorithm (Karhunen-Loève Image Projection) was developed for this project, and has proven very effective at processing the hundreds of selected archival images. This project has already been very successful with numerous detections of previously unseen point sources and several resolved debris disks that we are currently following up by multiple avenues. We give an overview of the project including preliminary scientific results with companion candidates and improved images of known disks
By reprocessing the NICMOS coronagraphic archive using improved PSF subtraction methods, we have obtained new images of 5 debris disks, all previously unseen using classical PSF subtractions. Three of the disks are edge on and two appear to be ring like, one of which is extremely asymmetric.
Their stellar hosts are nearby, young F and G type stars (40-90 pc, 12–30 Myr), including one that is a close analog to the young sun at roughly the age at which terrestrial planets were assembling. This is a 25% increase in the sample of debris disks seen in scattered light. Analysis and modeling of the disk geometries is in process. Given these systems' youth, proximity, and brightness (V = 7.2 to 8.5), these will be superb targets for investigating planet formation, and are perfect targets for studies with GPI, SPHERE and JWST.
The Gemini Planet Imager (GPI) is a high contrast coronagraph designed to directly image exoplanets and circumstellar disks. GPI includes a polarimetry mode designed to characterize dust grains and enhance the contrast of scattered, polarized light by a factor of 100. Reflections and birefringence of optics within the optical train induce a polarization signature that needs to be measured a priori and calibrated out during data reduction. Here we report on the results of an extensive laboratory characterization campaign of the polarimetry mode. The linear instrumental polarization has been measured in 4 GPI passbands and found to be between 3.5 ± 0.3 % at 1.0 micron and 1.1 ± 0.3 % at 2.0 microns. Modulation efficiency has been measured to be 94% at 1.0 micron increasing to 97% at 2.0 microns. Stability has been shown to better than 0.6% over timescales of ~ 3 months and over cool down cycles. The tests show that GPI passes all polarimetry design requirements and should be able to measure circumstellar disk linear polarization to 1% accuracy.
We present detailed models of the edge-on protoplanetary disk ESO Hα 569 (SSTgbs J111110.7-764157) from resolved scattered light images from HST and a complete spectral energy distribution. Data was obtained as part of an HST campaign to catalogue edge-on disks around young stars in nearby star forming regions (HST program 12514, PI: Karl Stapelfeldt). We confirm that this object is an optically thick edge-on disk around a young star with an outer radius of 125 AU. Using full radiative transfer models, we probe the distribution of dust grains and overall shape of the disk (inclination, scale height, dust mass, maximum particle size, inner radius, flaring exponent and surface/volume density exponent).
We report on a long-term monitoring of the cool supergiant Betelgeuse, using the NARVAL and ESPaDOnS high-resolution spectropolarimeters, respectively installed at Telescope Bernard Lyot (Pic du Midi Observatory, France) and at the Canada-France-Hawaii Telescope (Mauna Kea Observatory, Hawaii). The data set, constituted of circularly polarized (Stokes V) and intensity (Stokes I) spectra, was collected between 2010 and 2012. We investigate here the temporal evolution of magnetic field, convection and temperature at photospheric level, using simultaneous measurements of the longitudinal magnetic field component, the core emission of the Ca II infrared triplet, the line-depth ratio of selected photospheric lines and the radial velocity of the star.