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Reciprocal space mapping can be efficiently carried out using a position-sensitive x-ray detector (PSD) coupled to a traditional double-axis diffractometer. The PSD offers parallel measurement of the total scattering angle of all diffracted x-rays during a single rocking-curve scan. As a result, a two-dimensional reciprocal space map can be made in a very short time similar to that of a one-dimensional rocking-curve scan. Fast, efficient reciprocal space mapping offers numerous routine advantages to the x-ray diffraction analyst. Some of these advantages arc the explicit differentiation of lattice strain from crystal orientation effects in strain-relaxed heteroepitaxial layers; the nondestructive characterization of the size, shape and orientation of nanocrystalline domains in ordered-alloy epilayers; and the ability to measure the average size and shape of voids in porous epilayers. Here, the PSD-based diffractometer is described, and specific examples clearly illustrating the advantages of complete reciprocal space analysis are presented.
With the recent discovery of a dozen dusty star-forming galaxies and around 30 quasars at z > 5 that are hyper-luminous in the infrared (μ LIR > 1013 L⊙, where μ is a lensing magnification factor), the possibility has opened up for SPICA, the proposed ESA M5 mid-/far-infrared mission, to extend its spectroscopic studies toward the epoch of reionisation and beyond. In this paper, we examine the feasibility and scientific potential of such observations with SPICA’s far-infrared spectrometer SAFARI, which will probe a spectral range (35–230 μm) that will be unexplored by ALMA and JWST. Our simulations show that SAFARI is capable of delivering good-quality spectra for hyper-luminous infrared galaxies at z = 5 − 10, allowing us to sample spectral features in the rest-frame mid-infrared and to investigate a host of key scientific issues, such as the relative importance of star formation versus AGN, the hardness of the radiation field, the level of chemical enrichment, and the properties of the molecular gas. From a broader perspective, SAFARI offers the potential to open up a new frontier in the study of the early Universe, providing access to uniquely powerful spectral features for probing first-generation objects, such as the key cooling lines of low-metallicity or metal-free forming galaxies (fine-structure and H2 lines) and emission features of solid compounds freshly synthesised by Population III supernovae. Ultimately, SAFARI’s ability to explore the high-redshift Universe will be determined by the availability of sufficiently bright targets (whether intrinsically luminous or gravitationally lensed). With its launch expected around 2030, SPICA is ideally positioned to take full advantage of upcoming wide-field surveys such as LSST, SKA, Euclid, and WFIRST, which are likely to provide extraordinary targets for SAFARI.
Background: To determine whether exosomal microRNAs (miRNAs) in CSF of patients with FTD can serve as diagnostic biomarkers, we assessed miRNA expression in the Genetic FTD Initiative (GENFI) cohort and in sporadic FTD. Methods: GENFI participants were either carriers of a pathogenic mutation or at risk of carrying a mutation because a first-degree relative was a symptomatic mutation carrier. Exosomes were isolated from CSF of 23 -pre-symptomatic and 15 symptomatic mutation carriers, and 11 healthy non-mutation carriers. Expression of miRNAs was measured using qPCR arrays. MiRNAs differentially expressed in symptomatic compared to pre-symptomatic mutation carriers were evaluated in 17 patients with sporadic FTD, 13 patients with sporadic Alzheimer’s disease (AD), and 10 healthy controls (HCs). Results: In the GENFI cohort, miR-204-5p and miR-632 were significantly decreased in symptomatic compared to pre-symptomatic mutation carriers. Decrease of miR-204-5p and miR-632 revealed receiver operator characteristics with an area of 0.89 [90% CI: 0.79-0.98] and 0.81 [90% CI: 0.68-0.93], and when combined an area of 0.93 [90% CI: 0.87-0.99]. In sporadic FTD, only miR-632 was significantly decreased compared to sporadic AD and HCs. Decrease of miR-632 revealed an area of 0.89 [90% CI: 0.80-0.98]. Conclusions: Exosomal miR-204-5p and miR-632 have potential as diagnostic biomarkers for genetic FTD and miR-632 also for sporadic FTD.
IR spectroscopy in the range 12–230 μm with the SPace IR telescope for Cosmology and Astrophysics (SPICA) will reveal the physical processes governing the formation and evolution of galaxies and black holes through cosmic time, bridging the gap between the James Webb Space Telescope and the upcoming Extremely Large Telescopes at shorter wavelengths and the Atacama Large Millimeter Array at longer wavelengths. The SPICA, with its 2.5-m telescope actively cooled to below 8 K, will obtain the first spectroscopic determination, in the mid-IR rest-frame, of both the star-formation rate and black hole accretion rate histories of galaxies, reaching lookback times of 12 Gyr, for large statistically significant samples. Densities, temperatures, radiation fields, and gas-phase metallicities will be measured in dust-obscured galaxies and active galactic nuclei, sampling a large range in mass and luminosity, from faint local dwarf galaxies to luminous quasars in the distant Universe. Active galactic nuclei and starburst feedback and feeding mechanisms in distant galaxies will be uncovered through detailed measurements of molecular and atomic line profiles. The SPICA’s large-area deep spectrophotometric surveys will provide mid-IR spectra and continuum fluxes for unbiased samples of tens of thousands of galaxies, out to redshifts of z ~ 6.
Ion angular current and energy distributions are important parameters for ion thrusters, which are typically measured at a few tens of centimetres to a few metres distance from the thruster exit. However, fully kinetic particle-in-cell (PIC) simulations are not able to simulate such domain sizes due to high computational costs. Therefore, a parallelisation strategy of the code is presented to reduce computational time. The calculated ion beam angular distributions in the plume region are quite sensitive to boundary conditions of the potential, possible additional source contributions (e.g. from secondary electron emission at vessel walls) and charge exchange collisions. Within this work a model for secondary electrons emitted from the vessel wall is included. In order to account for limits of the model due to its limited domain size, a correction of the simulated angular ion energy distribution by the potential boundary is presented to represent the conditions at the location of the experimental measurement in
distance. In addition, a post-processing procedure is suggested to include charge exchange collisions in the plume region not covered by the original PIC simulation domain for the simulation of ion angular distributions measured at
Critical to the development of improved HIV elimination efforts is a greater understanding of how social networks and their dynamics are related to HIV risk and prevention. In this paper, we examine network stability of confidant and sexual networks among young black men who have sex with men (YBMSM). We use data from uConnect (2013–2016), a population-based, longitudinal cohort study. We use an innovative approach to measure both sexual and confidant network stability at three time points, and examine the relationship between each type of stability and HIV risk and prevention behaviors. This approach is consistent with a co-evolutionary perspective in which behavior is not only affected by static properties of an individual's network, but may also be associated with changes in the topology of his or her egocentric network. Our results indicate that although confidant and sexual network stability are moderately correlated, their dynamics are distinct with different predictors and differing associations with behavior. Both types of stability are associated with lower rates of risk behaviors, and both are reduced among those who have spent time in jail. Public health awareness and engagement with both types of networks may provide new opportunities for HIV prevention interventions.
Accurate models of X-ray absorption and re-emission in partly stripped ions are necessary to calculate the structure of stars, the performance of hohlraums for inertial confinement fusion and many other systems in high-energy-density plasma physics. Despite theoretical progress, a persistent discrepancy exists with recent experiments at the Sandia Z facility studying iron in conditions characteristic of the solar radiative–convective transition region. The increased iron opacity measured at Z could help resolve a longstanding issue with the standard solar model, but requires a radical departure for opacity theory. To replicate the Z measurements, an opacity experiment has been designed for the National Facility (NIF). The design uses established techniques scaled to NIF. A laser-heated hohlraum will produce X-ray-heated uniform iron plasmas in local thermodynamic equilibrium (LTE) at temperatures
eV and electron densities
. The iron will be probed using continuum X-rays emitted in a
diameter source from a 2 mm diameter polystyrene (CH) capsule implosion. In this design,
of the NIF beams deliver 500 kJ to the
mm diameter hohlraum, and the remaining
directly drive the CH capsule with 200 kJ. Calculations indicate this capsule backlighter should outshine the iron sample, delivering a point-projection transmission opacity measurement to a time-integrated X-ray spectrometer viewing down the hohlraum axis. Preliminary experiments to develop the backlighter and hohlraum are underway, informing simulated measurements to guide the final design.
The particle-in-cell (PIC) method was used to simulate heat flux mitigation experiments with partially ionised argon. The experiments demonstrate the possibility of reducing heat flux towards a target using magnetic fields. Modelling using the PIC method is able to reproduce the heat flux mitigation qualitatively. This is driven by modified electron transport. Electrons are magnetised and react directly to the external magnetic field. In addition, an increase of radial turbulent transport is also needed to explain the experimental observations in the model. Close to the target an increase of electron density is created. Due to quasi-neutrality, ions follow the electrons. Charge exchange collisions couple the dynamics of the neutrals to the ions and reduce the flow velocity of neutrals by radial momentum transport and subsequent losses. By this, the dominant heat-transport channel by neutrals gets reduced and a reduction of the heat deposition, similar to the experiment, is observed. Using the simulation a diagnostic module for optical emission is developed and its results are compared with spectroscopic measurements and photos from the experiment. The results of this study are in good agreement with the experiment. Experimental observations such as a shrank bright emission region close to the nozzle exit, an additional emission in front of the target and an overall change in colour to red are reproduced by the simulation.
The isotopic composition of ancient wood has the potential to provide information about past environments. We analyzed the δ13C, δ18O, and δ2H of cellulose of conifer trees from several cross-sections at each of 9 sites around the Great Lakes region ranging from ∼4000 to 14,000 cal BP. Isotopic values of Picea, Pinus, and Thuja species seem interchangeable for δ18O and δ2H comparisons, but Thuja appears distinctly different from the other 2 in its δ13C composition. Isotopic results suggest that the 2 sites of near-Younger Dryas age experienced the coldest conditions, although the Gribben Basin site near the Laurentide ice sheet was relatively dry, whereas the Liverpool site 500 km south was moister. The spatial isotopic variability of 3 of the 4 sites of Two Creeks age shows evidence of an elevation effect, perhaps related to sites farther inland from the Lake Michigan shoreline experiencing warmer daytime growing season temperatures. Thus, despite floristic similarity across sites (wood samples at 7 of the sites being Picea), the isotopes appear to reflect environmental differences that might not be readily evident from a purely floristic interpretation of macrofossil or pollen identification.
Start-up performance and first results of the new Woods Hole Accelerator Mass Spectrometer are discussed. Special attention is given to the hemispherical ionizer sputter source and the triple-isotope injector design.
This paper briefly describes the principle of operation and science goals of the AMANDA high energy neutrino telescope located at the South Pole, Antarctica. Results from an earlier phase of the telescope, called AMANDA-BIO, demonstrate both reliable operation and the broad astrophysical reach of this device, which includes searches for a variety of sources of ultrahigh energy neutrinos: generic point sources, Gamma-Ray Bursts and diffuse sources. The predicted sensitivity and angular resolution of the telescope were confirmed by studies of atmospheric muon and neutrino backgrounds. We also report on the status of the analysis from AMANDA-II, a larger version with far greater capabilities. At this stage of analysis, details of the ice properties and other systematic uncertainties of the AMANDA-II telescope are under study, but we have made progress toward critical science objectives. In particular, we present the first preliminary flux limits from AMANDA-II on the search for continuous emission from astrophysical point sources, and report on the search for correlated neutrino emission from Gamma Ray Bursts detected by BATSE before decommissioning in May 2000. During the next two years, we expect to exploit the full potential of AMANDA-II with the installation of a new data acquisition system that records full waveforms from the in-ice optical sensors.
The ESRO satellite COS-B carries one single experiment aiming at the measurement of arrival direction and energy of celestial gamma rays with energies between 25 MeV and 10 GeV. The experiment is conventional in design and consists of a veto counter, a wire spark chamber, a telescope and an energy calorimeter.
The energy measurement is obtained by a CsI scintillation crystal of 4.7 radiation length thickness. The expected energy resolution at 100 MeV is 50% FWHM. The other detector elements are designed as to cause the least possible degradation of the energy measurement.
The possibilities for the detection of a small contribution of π -origin gamma rays in the presence of a power-law type background spectrum will be discussed.
The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.
The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope1, MALT90 has obtained 3′ × 3′ maps towards ~2 000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to
regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38 arcsec) and spectral (0.11 km s−1) resolution, the data reveal a wealth of information about the clumps’ morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high-resolution studies with ALMA.
Depression and anxiety are major causes of absence from work and underperformance in the workplace. Cognitive behavioural therapy (CBT) can be effective in treating such problems and online versions offer many practical advantages. The aim of the study was to investigate the effectiveness of a computerized CBT intervention (MoodGYM) in a workplace context.
The study was a phase III two-arm, parallel randomized controlled trial whose main outcome was total score on the Work and Social Adjustment Scale (WSAS). Depression, anxiety, psychological functioning, costs and acceptability of the online process were also measured. Most data were collected online for 637 participants at baseline, 359 at 6 weeks marking the end of the intervention and 251 participants at 12 weeks post-baseline.
In both experimental and control groups depression scores improved over 6 weeks but attrition was high. There was no evidence for a difference in the average treatment effect of MoodGYM on the WSAS, nor for a difference in any of the secondary outcomes.
This study found no evidence that MoodGYM was superior to informational websites in terms of psychological outcomes or service use, although improvement to subthreshold levels of depression was seen in nearly half the patients in both groups.
The aim of this study was to determine the effect of butaphosphan and cyanocobalamin (BTPC) supplementation on plasma metabolites and milk production in postpartum dairy cows. A total of fifty-two Holstein cows were randomly assigned to receive either: (1) 10 ml of saline (NaCl 0.9%, control group); (2) 1000 mg of butaphosphan and 0.5 mg of cyanocobalamin (BTPC1 group); and (3) 2000 mg of butaphosphan and 1.0 mg of cyanocobalamin (BTPC2 group). All cows received injections every 5 days from calving to 20 days in milk (DIM). Blood samples were collected every 15 days from calving until 75 DIM to determine serum concentration of glucose, non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHB), cholesterol, urea, calcium (Ca), phosphorus (P), magnesium (Mg), aminotransferase aspartate (AST) and γ-glutamyltransferase (GGT). The body condition score (BCS) and milk production were evaluated from calving until 90 DIM. Increasing doses of BTPC caused a linear reduction in plasma concentrations of NEFA and cholesterol. Supplementation of BTPC also reduced concentrations of BHB but it did not differ between the two treatment doses. Milk yield and milk protein had a linear increase with increasing doses of BTPC. A quadratic effect was detected for milk fat and total milk solids according to treatment dose, and BTPC1 had the lowest mean values. Concentrations of glucose, urea, P, Mg, AST, GGT, milk lactose and BCS were not affected by treatment. These results indicate that injections of BTPC during the early postpartum period can reduce NEFA and BHB concentrations and increase milk production in Holstein cows.
Bismuth ferrite (BiFeO3) is a magnetoelectric, multiferroic material with coexisting ferroelectric and magnetic orderings. It is considered as a candidate for the next generation of ferroelectric random-access memory devices because BiFeO3, in contrast to industrial ferroelectrics used today, does not contain the toxic element lead. Furthermore, its polarization values are higher than those of lead-based ferroelectrics. The magnitude of the polarization of a BiFeO3 film is dependent on its orientation and is related to the domain structure. This contribution presents and discusses the preparation of epitaxial BiFeO3 (BFO) thin films grown on SrRuO3/SrTiO3 substrates by pulsed laser deposition (PLD) and their characterization, especially by piezo force microscopy (PFM) and atomic force acoustic microscopy (AFAM). The thickness of an individual BFO film varies between 100 and 200 nm. The epitaxial nature of films in the crystallographic (100), (110), and (111) directions was confirmed by x-ray diffraction (XRD). Thin SrRuO3 layers, also prepared by PLD, were used as bottom electrode for the ferroelectric hysteresis measurements. Low frequency PFM measurements showed a monodomain structure for the as-grown (110) and (111) oriented samples. In BFO (100) films, different polarization variants were observed by ultrasonic piezo force microscopy (UPFM). The domain structure is reproduced from minimization of the electrostatic and elastic energies. Switching experiments using standard PFM as well as UPFM were carried out on the three samples with the objective of testing the coercive field and domain stability. The AFAM technique was used to map the elastic properties of the BFO thin-films at the micro- and nanoscale.