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The search for life in the Universe is a fundamental problem of astrobiology and modern science. The current progress in the detection of terrestrial-type exoplanets has opened a new avenue in the characterization of exoplanetary atmospheres and in the search for biosignatures of life with the upcoming ground-based and space missions. To specify the conditions favourable for the origin, development and sustainment of life as we know it in other worlds, we need to understand the nature of global (astrospheric), and local (atmospheric and surface) environments of exoplanets in the habitable zones (HZs) around G-K-M dwarf stars including our young Sun. Global environment is formed by propagated disturbances from the planet-hosting stars in the form of stellar flares, coronal mass ejections, energetic particles and winds collectively known as astrospheric space weather. Its characterization will help in understanding how an exoplanetary ecosystem interacts with its host star, as well as in the specification of the physical, chemical and biochemical conditions that can create favourable and/or detrimental conditions for planetary climate and habitability along with evolution of planetary internal dynamics over geological timescales. A key linkage of (astro)physical, chemical and geological processes can only be understood in the framework of interdisciplinary studies with the incorporation of progress in heliophysics, astrophysics, planetary and Earth sciences. The assessment of the impacts of host stars on the climate and habitability of terrestrial (exo)planets will significantly expand the current definition of the HZ to the biogenic zone and provide new observational strategies for searching for signatures of life. The major goal of this paper is to describe and discuss the current status and recent progress in this interdisciplinary field in light of presentations and discussions during the NASA Nexus for Exoplanetary System Science funded workshop ‘Exoplanetary Space Weather, Climate and Habitability’ and to provide a new roadmap for the future development of the emerging field of exoplanetary science and astrobiology.
In the last decade observations have been able to probe the evolution of the galaxy luminosity function, in particular showing a variation of its faint-end with redshift. We employ the data of the Cluster-EAGLE project, a set of cosmological, hydrodynamical zoom-in simulations of 30 galaxy clusters, to study the evolution of the galaxy luminostity functions in clusters with redshift. We compile a catalogue of simulated galaxies’ luminosities in the SDSS bands using the E-MILES spectra database, and taking into account dust attenuation. Stacked luminosity functions present little evolution with redshift of the faint-end slope from z=3.5 to z=0, regardless of the cluster mass.
The Murchison Widefield Array is a Square Kilometre Array Precursor. The telescope is located at the Murchison Radio–astronomy Observatory in Western Australia. The MWA consists of 4 096 dipoles arranged into 128 dual polarisation aperture arrays forming a connected element interferometer that cross-correlates signals from all 256 inputs. A hybrid approach to the correlation task is employed, with some processing stages being performed by bespoke hardware, based on Field Programmable Gate Arrays, and others by Graphics Processing Units housed in general purpose rack mounted servers. The correlation capability required is approximately 8 tera floating point operations per second. The MWA has commenced operations and the correlator is generating 8.3 TB day−1 of correlation products, that are subsequently transferred 700 km from the MRO to Perth (WA) in real-time for storage and offline processing. In this paper, we outline the correlator design, signal path, and processing elements and present the data format for the internal and external interfaces.
It is uncertain whether antipsychotic long-acting injection (LAI) medication in schizophrenia is associated with better clinical outcomes than oral preparations.
To examine the impact of prior treatment delivery route on treatment outcomes and whether any differences are moderated by adherence.
Analysis of data from two pragmatic 1-year clinical trials in which patients with schizophrenia were randomised to either an oral first-generation antipsychotic (FGA), or a non-clozapine second-generation antipsychotic (SGA, CUtLASS 1 study), or a non-clozapine SGA or clozapine (CUtLASS 2 study).
Across both trials, 43% (n = 155) of participants were prescribed an FGA-LAI before randomisation. At 1-year follow-up they showed less improvement in quality of life, symptoms and global functioning than those randomised from oral medication. This difference was confined to patients rated as less than consistently adherent pre-randomisation. The relatively poor improvement in the patients prescribed an LAI pre-randomisation was ameliorated if they had been randomised to clozapine rather than another SGA. There was no advantage to being randomly assigned from an LAI at baseline to a non-clozapine oral SGA rather than an oral FGA.
A switch at randomisation from an LAI to an oral antipsychotic was associated with poorer clinical and functional outcomes at 1-year follow-up compared with switching from one oral antipsychotic to another. This effect appears to be moderated by adherence, and may not extend to switching to clozapine. This has implications for clinical trial design: the drug from which a participant is randomised may have a greater effect than the drug to which they are randomised.
The Murchison Widefield Array (MWA) is one of three Square Kilometre Array Precursor telescopes and is located at the Murchison Radio-astronomy Observatory in the Murchison Shire of the mid-west of Western Australia, a location chosen for its extremely low levels of radio frequency interference. The MWA operates at low radio frequencies, 80–300 MHz, with a processed bandwidth of 30.72 MHz for both linear polarisations, and consists of 128 aperture arrays (known as tiles) distributed over a ~3-km diameter area. Novel hybrid hardware/software correlation and a real-time imaging and calibration systems comprise the MWA signal processing backend. In this paper, the as-built MWA is described both at a system and sub-system level, the expected performance of the array is presented, and the science goals of the instrument are summarised.
Second-generation antipsychotics have been thought to cause fewer
extrapyramidal side-effects (EPS) than first-generation antipsychotics,
but recent pragmatic trials have indicated equivalence.
To determine whether second-generation antipsychotics had better outcomes
in terms of EPS than first-generation drugs.
We conducted an intention-to-treat, secondary analysis of data from an
earlier randomised controlled trial (n = 227). A
clinically significant difference was defined as double or half the
symptoms in groups prescribed first- v.
second-generation antipsychotics, represented by odds ratios greater than
2.0 (indicating advantage for first-generation drugs) or less than 0.5
(indicating advantage for the newer drugs). We also examined EPS in terms
of symptoms emergent at 12 weeks and 52 weeks, and symptoms that had
resolved at these time points.
At baseline those randomised to the first-generation antipsychotic group
(n = 118) had similar EPS to the second-generation
group (n = 109). Indications of resolved Parkinsonism
(OR = 0.5) and akathisia (OR = 0.4) and increased tardive dyskinesia (OR
= 2.2) in the second-generation drug group at 12 weeks were not
statistically significant and the effects were not present by 52 weeks.
Patients in the second-generation group were dramatically (30-fold) less
likely to be prescribed adjunctive anticholinergic medication, despite
equivalence in terms of EPS.
The expected improvement in EPS profiles for participants randomised to
second-generation drugs was not found; the prognosis over 1 year of those
in the first-generation arm was no worse in these terms. The place of
careful prescription of first-generation drugs in contemporary practice
remains to be defined, potentially improving clinical effectiveness and
avoiding life-shortening metabolic disturbances in some patients
currently treated with the narrow range of second-generation
antipsychotics used in routine practice. This has educational
implications because a generation of psychiatrists now has little or no
experience with first-generation antipsychotic prescription.
An evaluation has been undertaken of the efficiency of laminar-flow ventilation in operating-rooms in which conventional operating-room clothing was used. It has been demonstrated that velocities in the region of 0·3–0·4 m/sec. will give maximum returns for effort in both down-flow and cross-flow systems. At this velocity the laminar-flow system, in terms of airborne bacteria measured at the would site, was about 11 times more effients using horizontal air-flow and 35–90 times more efficient using vertical air-flow than a plenum-ventilated operating room.
Pr doped YBa2Cu3O7-d targets with composition Y1-xPrxBa2Cu3O7-d where × = 0.0001, 0.001, 0.01, and 0.1 were prepared from oxide powders and were used to deposit thin films by pulsed laser deposition using conditions previously optimized for pure YBa2Cu3O7-d. The Pr dopant was found to be dispersed throughout the film by secondary ion mass spectrometry and found to have an increased density of nanoparticles on the surface. The pinning force of the doped samples was found to decrease with increasing concentration of Pr; however, at 0.01% concentration the doped film displayed a significant enhancement over pure YBa2Cu3O7-d for nearly the full range of 0 – 9 T.
A new approach for the production of yttria-stabilized zirconia (YSZ) oxide buffer layers directly on metal rolling-assisted biaxially textured substrates (RABiTS) is described in this paper. This represents a significant advance over existing techniques and avoids the need for complicated steps to avoid substrate oxidation during direct deposition of oxides. Current densities of about 1 MA/cm2 have been achieved for YBa2Cu3O7-δ layers on the YSZ buffer, with an intermediate CeO2 layer. The process consists of reactive sputtering of a YxZr1−xN film directly on the RABiTS, which adopts its biaxial texture. This nitride film is then converted to YSZ via a thermal oxidation step. The YSZ films retain the texture of the nitride film (and of the RABiTS) through local syntaxy. In many cases, YSZ films exhibit improved biaxial texture over that of the RABiTS substrate. Nitrides can be sputter deposited at much higher rates relative to oxides, making the approach industrially scalable and economical.
Background. We tested the hypothesis that schizophrenia
is primarily a frontostriatal disorder by
examining executive function in first-episode patients. Previous studies
have shown either equal
decrements in many cognitive domains or specific deficits in memory.
Such studies have grouped test
results or have used few executive measures, thus, possibly losing information.
measured a range of executive ability with tests known to be sensitive
to frontal lobe function.
Methods. Thirty first-episode schizophrenic patients and 30
volunteers, matched for age and
NART IQ, were tested on computerized test of planning, spatial working
memory and attentional
set shifting from the Cambridge Automated Neuropsychological Test Battery.
traditional tests of memory were also administered for comparison.
Results. Patients were worse on all tests but the profile was
non-uniform. A componential analysis
indicated that the patients were characterized by a poor ability to think
ahead and organize
responses but an intact ability to switch attention and inhibit prepotent
responses. Patients also demonstrated poor memory, especially for free
recall of a story and
associate learning of unrelated word pairs.
Conclusions. In contradistinction to previous studies,
schizophrenic patients do have profound
executive impairments at the beginning of the illness. However, these
concern planning and strategy
use rather than attentional set shifting, which is generally unimpaired.
Previous findings in more
chronic patients, of severe attentional set shifting impairment, suggest
that executive cognitive
deficits are progressive during the course of schizophrenia. The finding
of severe mnemonic
impairment at first episode suggests that cognitive deficits are not
restricted to one cognitive domain.
Data from the F1, F2 and F3 generations derived from four F1 hybrids of sunflower were analysed to determine the genetical control of eleven agronomically important traits namely, flowering time (FT), final height (FH), seed set (SS), fresh seed weight (FSW), dry seed weight (DSW), 25-seed weight (SSW), head diameter (HD), head angle (HA), neck width (NW), Botrylis infection (BI) and percentage oil content (PO), with the objective of assessing their potential for producing superior recombinant lines. Comparisons of means revealed significant differences between the F: generations of crosses for all the characters except FT. Model fitting indicated that these differences were attributed either to variation in the magnitude of the dominance component [h], or the projected mean of the Finfin; generation, m. Further, all the variation in the generation means was accounted for by the m and [h] parameters and epistasis was shown to be non-existent for almost all the traits. Analysis of the second degree statistics revealed the presence of additive genetic effects and most of the characters showed moderate heritability except for HD, which was highly heritable. All the crosses were predicted to produce significant numbers of transgressive segregants and consequently were expected to yield superior inbred lines and second cycle hybrids either to be released as varieties as such or to be utilized in future breeding work. The overall differences between the crosses, however, were not highly pronounced and therefore it was not possible to identify a cross which would yield markedly superior recombinant lines and F1 crosses compared to the others.
Thin films of ZnO have been grown on silicon and glass substrates by the pulsed laser deposition method. The effects of the oxygen partial pressure, substrate temperature and laser wavelength on the structural and optical properties of the films have been studied. The KrF excimer laser (at 248 nm) was found to produce better quality thin films than the frequency doubled Nd:YAG laser (532 nm). Layers produced at substrate temperatures as low as 300°C were c-axis oriented with a FWHM value for the 002 XRD reflection less than 0.2° and exhibited optical transmission higher than 80% in the visible region.
We have investigated the effect on a silicon surface of both wet chemical and cluster-tool UV/ozone cleaning, prior to UHV processing to fabricate MOS test structures. The physical and chemical condition of the Si surface has been examined by Scanning Tunnelling and Atomic Force Microscopy (STM, AFM) and Medium Energy Ion Scattering (MEIS). After MOS fabrication some of the structures were examined by Cross-sectional Transmission Electron Microscopy (TEM). The electrical performance of the MOS test sets were characterized by breakdown voltage measurements.
We have found correlations between the electrical performance of the MOS devices, the structure of the Si surface prior to oxidation, and the details of the UHV fabrication technique. In particular any MOS device fabricated on a Si surface thermally cleaned in UHV prior to oxidation has a poor breakdown strength. We have found that this is the result of the formation of silicon carbide on the Si surface at high temperature and the subsequent local disruption of the oxidation step of MOS fabrication by the SiC. A UHV cleaning procedure has been developed to avoid this C contamination problem.
Reactive pulsed laser deposition of titanium targets in a nitrogen atmosphere has been used to deposit thin titanium oxynitride films on Si substrates. The gold coloured layers exhibited a smooth, featureless surface and good chemical resistance in HF-HNO3 mixtures. The films had a high oxygen content which was responsible for relatively high electrical resistivity, measured to be 200–600 μΩ cm. This new method can easily be applied to the growth of other important nitrides such as ZrN, WN, HfN or the deposition of multilayer structures such as TiN/Ti on a variety of substrates.