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A number of laser facilities coming online all over the world promise the capability of high-power laser experiments with shot repetition rates between 1 and 10 Hz. Target availability and technical issues related to the interaction environment could become a bottleneck for the exploitation of such facilities. In this paper, we report on target needs for three different classes of experiments: dynamic compression physics, electron transport and isochoric heating, and laser-driven particle and radiation sources. We also review some of the most challenging issues in target fabrication and high repetition rate operation. Finally, we discuss current target supply strategies and future perspectives to establish a sustainable target provision infrastructure for advanced laser facilities.
The evolution of massive stars encompasses short-lived transition phases in which mass-loss is more enhanced and usually eruptive. A complex environment, combining atomic, molecular and dust regions, is formed around these stars. In particular, the circumstellar environment of B[e] Supergiants is not well understood. To address that, we have initiated a campaign to investigate their environments for a sample of Galactic and Magellanic Cloud sources. Using high-resolution optical and near-infrared spectra (MPG-ESO/FEROS, GEMINI/Phoenix and VLT/CRIRES, respectively), we examine a set of emission features ([OI], [CaII], CO bandheads) to trace the physical conditions and kinematics in their formation regions. We find that the B[e] Supergiants are surrounded by a series of rings of different temperatures and densities, a probable result of previous mass-loss events. In many cases the CO forms very close to the star, while we notice also an alternate mixing of densities and temperatures (which give rise to the different emission features) along the equatorial plane.
We report on current Mars mapping projects in support of NASA planetary exploration. This includes a summary of the current state and accuracy of such mapping at global, regional, and local (human) scales. The availability of Mars Orbiter Laser Altimeter data has revolutionized such mapping. Aside from its use as a global topographic dataset, images can easily be correlated to it with absolute uncertainties of ≈100 m horizontally. We are using this to create a revised version of the global Mars digital image mosaic (MDIM) that will have absolute errors of ≈231 m (one pixel) and improved cosmetic characteristics. We are undertaking stereo-topographic mapping at regional to local scales, using Viking and Mars Orbiter Camera Narrow Angle (NA) images, with horizontal resolutions of 600 to 5 m, and expected vertical precision of 200 to 1 m. Derived topography and altimetric information can also be used to calibrate shape-from-shading (photoclinometry) topographic models at down to single-pixel resolution (i.e. 1.4 m for NA images). Products of these efforts have a multitude of purposes, from assisting in large-scale geologic mapping, to characterizing the geology/safety of proposed landing sites. Plans are underway to also use THEMIS, HRSC, and HiRISE camera data in future efforts.
Further to the publication by the London School of Economics and Political Science of the report Ending the Drug Wars, this editorial focuses on the mental health impact of the ‘war on drugs' and on the need to end such policies in favour of evidence-based interventions to manage drug dependence as a health condition.
Dansgaard–Oeschger (D–O) cycles had far-reaching effects on Northern Hemisphere and tropical climate systems during the last glacial period, yet the climatic response to D–O cycles in western North America is controversial, especially prior to 55 ka. We document changes in precipitation along the western slope of the central Sierra Nevada during early Marine Oxygen Isotope Stages (MIS) 3 and 4 (55–67 ka) from a U-series dated speleothem record from McLean's Cave. The timing of our multi-proxy geochemical dataset is coeval with D–O interstadials (15–18) and stadials, including Heinrich Event 6. The McLean's Cave stalagmite indicates warmer and drier conditions during Greenland interstadials (GISs 15–18), signified by elevated δ18O, δ13C, reflectance, and trace element concentrations, and less radiogenic 87Sr/86Sr. Our record extends evidence of a strong linkage between high-latitude warming and reduced precipitation in western North America to early MIS 3 and MIS 4. This record shows that the linkage persists in diverse global climate states, and documents the nature of the climatic response in central California to Heinrich Event 6.
A new radiation-driven wind solution called δ-slow was found by Curé et al. (2011) and it predicts a mass-loss rate and terminal velocity slower than the fast solution (m-CAK, Pauldrach et al. 1986). In this work, we present our first synthetic spectra based on the δ-slow solution for the wind of B supergiant (BSG) stars. We use the output of our hydrodynamical code HYDWIND as input in the radiative transport code FASTWIND (Puls et al. 2005). In order to obtain stellar and wind parameters, we try to reproduce the observed Hα, Hβ, Hγ, Hδ, Hei 4471, Hei 6678 and Heii 4686 lines. The synthetic profiles obtained with the new hydrodynamical solutions are in good agreement with the observations and could give us clues about the parameters involved in the radiation force.
Elucidating the cognitive architecture of schizophrenia promises to advance understanding of the clinical and biological substrates of the illness. Traditional cross-sectional neuropsychological approaches differentiate impaired from normal cognitive abilities but are limited in their ability to determine latent substructure. The current study examined the latent architecture of abnormal cognition in schizophrenia via a systematic approach.
Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were carried out on a large neuropsychological dataset including the Brief Assessment of Cognition in Schizophrenia, Continuous Performance Test, Wisconsin Card Sorting Test, Benton Judgment of Line Orientation Test, and Wechsler Abbreviated Scale of Intelligence matrix reasoning derived from 1012 English-speaking ethnic Chinese healthy controls and 707 schizophrenia cases recruited from in- and out-patient clinics.
An initial six-factor model fit cognitive data in healthy and schizophrenia subjects. Further modeling, which accounted for methodological variance between tests, resulted in a three-factor model of executive functioning, vigilance/speed of processing and memory that appeared to best discriminate schizophrenia cases from controls. Factor analytic-derived g estimands and conventionally calculated g showed similar case–control discrimination. However, agreement analysis suggested systematic differences between both g indices.
Factor structures derived in the current study were broadly similar to those reported previously. However, factor structures between schizophrenia subjects and healthy controls were different. Roles of factor analytic-derived g estimands and conventional composite score g were further discussed. Cognitive structures underlying cognitive deficits in schizophrenia may prove useful for interrogating biological substrates and enriching effect sizes for subsequent work.
Postpartum depression (PPD) affects approximately 13% of women and has a negative impact on mother and infant, hence reliable biological tests for early detection of PPD are essential. We aimed to identify robust predictive biomarkers for PPD using peripheral blood gene expression profiles in a hypothesis-free genome-wide study in a high-risk, longitudinal cohort.
We performed a genome-wide association study in a longitudinal discovery cohort comprising 62 women with psychopathology. Gene expression and hormones were measured in the first and third pregnancy trimesters and early postpartum (201 samples). The replication cohort comprised 24 women with third pregnancy trimester gene expression measures. Gene expression was measured on Illumina-Human HT12 v4 microarrays. Plasma estradiol and estriol were measured. Statistical analysis was performed in R.
We identified 116 transcripts differentially expressed between the PPD and euthymic women during the third trimester that allowed prediction of PPD with an accuracy of 88% in both discovery and replication cohorts. Within these transcripts, significant enrichment of transcripts implicated that estrogen signaling was observed and such enrichment was also evident when analysing published gene expression data predicting PPD from a non-risk cohort. While plasma estrogen levels were not different across groups, women with PPD displayed an increased sensitivity to estrogen signaling, confirming the previously proposed hypothesis of increased sex-steroid sensitivity as a susceptibility factor for PPD.
These results suggest that PPD can be robustly predicted in currently euthymic women as early as the third trimester and these findings have implications for predictive testing of high-risk women and prevention and treatment for PPD.
In order to understand how N2 plasma conditions impact on the incorporation of nitrogen species into a thin SiO2 (1.4 nm), tuning of some pulsed RF (pRF) Decoupled Plasma Nitridation (DPN) process parameters was performed: duty cycle (DC) or on-time per period, frequency (f), process time (t) and some cross-combinations (DC*f, DC*t, DC*f*t). The N2 plasma and the SiOx Ny film were characterized using Langmuir probe analysis (LP) and Delay to Reoxidation (D2R) techniques, respectively. Correlations are established between ion density and electron temperature and the resultant nitrogen concentration and parasitic physical thickness increase. The LP results indicate that while DC impacts the ion density and energy, the frequency has no impact to first order. This is consistent with the physical characteristics of the film. From the combination of DC*f*t, the importance of the off-time portion of the pulse was revealed. With the help of a modified pulsed RF DPN generator, allowing a decrease of the frequency down to 2 kHz, a 5% improvement of the drive current for pMOS transistors was obtained.
This article identifies ways to overcome impediments to restoring natural features on developed shores where human-use functions are the dominant driving forces. Suggestions are made for (1) incorporating natural features and natural dynamism into beach nourishment projects; (2) addressing constraints in size and space; (3) reducing the impact of human actions and elements in the landscape; (4) integrating endangered species programmes; (5) overcoming impediments to implementing restoration projects; (6) conducting post-construction evaluations and actions; (7) obtaining public support; and (8) addressing regulatory issues. Beach nourishment projects can better mimic natural landforms, while protecting infrastructure and habitat, creating space for dunes, and providing sediment for dune building. Dunes can have more value as habitat if sub-environments representative of natural gradients are accommodated. Greater human effort will be required to maintain both dynamic and stable zones for habitat, and these zones may be restricted to smaller scales. Controls can be placed on human actions, such as raking the beach, driving on the beach, walking through the dune, emplacing more structures than necessary and introducing exotic vegetation for landscaping. Regulatory restrictions that now prevent environmentally friendly actions can be eased, and adaptive management and education programmes can be implemented.
Prompted by earlier work showing that graphite intercalation compounds form superconducting ternary compounds in which thallium plays an important role C60 has been doped with Tl-alloys. Results of dc-magnetization, ac-susceptibility, X-ray analysis and NMR investigations will be presented.
The CRESST-II direct Dark Matter search is located in the Gran Sasso underground laboratories, Italy. CaWO4 crystals are used as scintillating targets for WIMP (weakly interacting massive particle) interactions. They are operated as cryogenic calorimeters in combination with a second cryogenic detector used to measure the scintillation light produced in the target crystal. For each particle interaction, the combination of phonon and light signals provides an event by event discrimination which allows to distinguish known particles (alphas, betas, gammas, neutrons) from the expected signal of WIMPs. A major upgrade of the setup comprises modifications of the shielding, installation of a muon-veto, and new read out electronics, as well as a new detector-support structure to accommodate up to 33 detector modules, i.e. 10 kg of target mass. The experiment was thereafter successfully commissioned in 2007. Data obtained during this commissioning phase from 2 detector modules are presented here. Combining the data collected with these two detector modules with data from one single module obtained during the CRESST-I phase, the experiment could already place a limit of ~6 × 10-7 pb for the spin independent WIMP-nucleon scattering cross section at a WIMP mass of ~60 GeV/c2.
EURECA (European Underground Rare Event Calorimeter Array) is an
astro-particle physics facility aiming to directly detect galactic dark
matter. The Laboratoire Souterrain de Modane has been selected as host
laboratory. The EURECA collaboration unites CRESST, EDELWEISS and the
Spanish-French experiment ROSEBUD, thus concentrating and focussing effort
on cryogenic detector research in Europe into a single facility. EURECA will
use a target mass of up to one ton, enough to explore WIMP – nucleon scalar
scattering cross sections in the region of 10-9 – 10-10 picobarn.
A major advantage of EURECA is the planned use of more than just one target
material (multi target experiment for WIMP identification).
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