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Visible to short-wave infrared (VSWIR, 0.4–5.0 µm) reflectance spectroscopy is a powerful tool to identify and map mineral groups on the martian surface. The Mars Express/OMEGA and Mars Reconnaissance Orbiter/CRISM instruments have characterized more than 30 mineral groups, revolutionizing previous understanding of martian crustal composition and the role of water in altering it. Analyses of these spectral images revealed the primary structure of the crust to be dominated by basalt, over a deep layer of segregated pyroxene- and olivine-rich plutons, with sparse feldspar-rich, differentiated intrusions. Martian volatile-bearing environments have evolved through four phases: the pre-Noachian to early Noachian period when alteration by liquid water occurred near the surface and deep in the subsurface, in chemically neutral to alkaline environments that formed hydrous silicates and carbonates; the middle to late Noachian period when liquid water was widely present at the surface forming valley networks, lacustrine deposits, and clay-rich pedogenic horizons; the early Hesperian to early Amazonian period during which water became increasingly acidic and saline, forming deposits rich in sulfate salts, chlorides, and hydrated silica; and the Amazonian period when surface water has existed predominantly as ice, with only localized reaction with regolith and briny flow on the surface.
The value of the nosological distinction between non-affective and affective psychosis has frequently been challenged. We aimed to investigate the transdiagnostic dimensional structure and associated characteristics of psychopathology at First Episode Psychosis (FEP). Regardless of diagnostic categories, we expected that positive symptoms occurred more frequently in ethnic minority groups and in more densely populated environments, and that negative symptoms were associated with indices of neurodevelopmental impairment.
This study included 2182 FEP individuals recruited across six countries, as part of the EUropean network of national schizophrenia networks studying Gene–Environment Interactions (EU-GEI) study. Symptom ratings were analysed using multidimensional item response modelling in Mplus to estimate five theory-based models of psychosis. We used multiple regression models to examine demographic and context factors associated with symptom dimensions.
A bifactor model, composed of one general factor and five specific dimensions of positive, negative, disorganization, manic and depressive symptoms, best-represented associations among ratings of psychotic symptoms. Positive symptoms were more common in ethnic minority groups. Urbanicity was associated with a higher score on the general factor. Men presented with more negative and less depressive symptoms than women. Early age-at-first-contact with psychiatric services was associated with higher scores on negative, disorganized, and manic symptom dimensions.
Our results suggest that the bifactor model of psychopathology holds across diagnostic categories of non-affective and affective psychosis at FEP, and demographic and context determinants map onto general and specific symptom dimensions. These findings have implications for tailoring symptom-specific treatments and inform research into the mood-psychosis spectrum.
Engagement and training of educators in student mental health holds promise for promoting access to care as a task sharing strategy but has not been well-studied in low-income regions.
We used a prospective and convergent mixed methods design to evaluate a customized school mental health 2½ day training for teachers in rural Haiti (n = 22) as the initial component of formative research developing a school-based intervention to promote student mental health. Training prepared teachers to respond to student mental health needs by providing psychoeducational and practical support to facilitate access to care. We examined level of participation and evaluated feasibility, acceptability, and perceived effectiveness by calculating mean scores on self-report Likert-style items eliciting participant experience. We examined effectiveness of the training on improving mental health knowledge and attitudes by comparing mean scores on an assessment administered pre- and post-training. Finally, we examined self-report written open-ended responses and focus group discussion (FGD) interview data bearing on perceived feasibility, acceptability, and effectiveness to contextualize participant ratings of training and to identify recommendations for enhancing the utility of mental health training locally for educators.
Mean scores of knowledge and attitudes significantly improved between the pre-test and post-tests; e.g., knowledge improved from 58% correct at baseline to 68% correct on the second post-test (p = 0.039). Mean ratings of the training were favorable across all categories and FGD data demonstrated widespread participant endorsement of training acceptability and effectiveness; participants recommended extending the duration and number of training sessions.
Findings support feasibility, acceptability, and a limited scope of effectiveness of brief mental health training for secondary school teachers in Haiti. Further development of approaches to engage teachers in promoting school mental health through training is warranted.
This study investigated local perceptions of changes stemming from a long-standing Group Interpersonal Psychotherapy (IPT-G) program for the treatment of depression in rural Uganda. The study was conducted in a low-income, severely HIV/AIDS-affected area where in 2001 the prevalence of depression was estimated at 21% among adults.
Data were collected using free-listing and key informant qualitative interviews. A convenience sample of 60 free-list respondents was selected from among IPT-G participants, their families, and other community members from 10 Ugandan villages. Twenty-two key informants and six IPT-G facilitators were also interviewed.
Content analysis yielded five primary categories of change in the community related to the IPT-G program: (1) improved school attendance for children; (2) improved productivity; (3) improved sanitation in communities; (4) greater cohesion among community members; and (5) reduced conflict in families. Community members and IPT-G facilitators suggested that as depression remitted, IPT-G participants became more hopeful, motivated and productive.
Results suggest that providing treatment for depression in communities with high depression prevalence rates may lead to positive changes in a range of non-mental health outcomes.
The accumulation of evidence now strongly favours interstellar scintillation (ISS) as the principal mechanism causing intra-day variability (IDV) at cm wavelengths. While ISS reduces the implied brightness temperatures, they remain uncomfortably high. The distance to the scattering screen is an important parameter in determining the actual brightness temperature encountered. The high brightness temperatures, the presence of strong and variable circular polarization and the observed lifetimes of a decade or more for several IDV sources, pose significant problems for synchrotron theory.
“The fault, dear Brutus, is not in our stars, but in ourselves, that we are underlings.” William Shakespeare, Julius Caesar
Intra-day variability (IDV) of active galactic nuclei (AGN) has been detected from gamma-ray energies to radio wavelengths. At high energies, such variability appears to be intrinsic to the sources themselves. However, at radio wavelengths, brightness temperatures as high as 1018 to 1021 K are encountered if the IDV is intrinsic to the source. We discuss here the accumulating evidence showing that, at radio wavelengths where the highest brightness temperatures are encountered, interstellar scintillation (ISS) is the principal mechanism causing IDV. While ISS reduces the implied brightness temperatures, they still remain uncomfortably high.
PKS 1257—326 is one of three quasars known to show unusually large and rapid, intra-hour intensity variations, as a result of scintillation in the turbulent Galactic interstellar medium. We have measured time delays in the variability pattern arrival times at the VLA and the ATCA, as well as an annual cycle in the time-scale of variability for this source. Results of the two-station time delay observations are presented here. Implications for the scintillation of this source are discussed in the light of these results, together with results from two years of monitoring with the ATCA.
We present a catalogue containing the redshifts of 3 660 X-ray selected targets in the XXL southern field. The redshifts were obtained with the AAOmega spectrograph and 2dF fibre positioner on the Anglo-Australian Telescope. The catalogue contains 1 515 broad line AGN, 528 stars, and redshifts for 41 out of the 49 brightest X-ray selected clusters in the XXL southern field.
Incorporation of Mg in metalorganic vapour phase epitaxy (MOVPE) GaN has been investigated, using two different Mg precursors: bis-methylcyclopentadienyl magnesium [(MeCp)2Mg] and Solution bis-cyclopentadienyl magnesium [Solution Cp2Mg]. SIMS analysis reveals an increased (two fold) efficiency of Mg incorporation for Solution Cp2Mg as compared to (MeCp)2Mg. These results are attributed to the stronger interaction of (MeCp)2Mg with NH3, leading to the formation of alkylmagnesium amine adducts, and a reduced effective Mg surface concentration. A decreased GaN growth rate with increasing Mg fluxes is also reported for both precursors. This effect is more pronounced for Solution Cp2Mg indicating that incorporation of Mg in the lattice proceeds via the capture of Mg into group III sites, and that the supply of Mg from the surface is reduced in the case when (MeCp)2Mg is used.
Flux density monitoring data at 2.3 and 8.4 GHz is presented for a sample of 33 southern hemisphere GPS sources, drawn from the 2.7 GHz Parkes survey. This monitoring data, together with VLBI monitoring data, shows that a small fraction of these sources, ∼10%, vary. Their variability falls into several categories: sources whose spectral classification is, at best, ephemeral on a timescale of years; sources with a stable GPS classification that vary, but retain their classification; and a small number of sources that exhibit interstellar scintillation, but that maintain a mean GPS spectrum. Existing data on GPS sources with higher frequency peaks, ≥3 GHz, reveals that many such sources vary. However, the majority of these sources possess a GPS spectrum only during outbursts, and hence should perhaps be classified as ephemeral GPS sources. In addition, significant levels of circular polarisation have been found in a number of GPS sources, both amongst the variables and non-variables. Remarkable amongst these is PKS 1519–273, which possesses strong and variable circular polarisation, and which exhibits IDV in all Stokes parameters.
The Australian Square Kilometre Array Pathfinder (ASKAP) will give us an unprecedented opportunity to investigate the transient sky at radio wavelengths. In this paper we present VAST, an ASKAP survey for Variables and Slow Transients. VAST will exploit the wide-field survey capabilities of ASKAP to enable the discovery and investigation of variable and transient phenomena from the local to the cosmological, including flare stars, intermittent pulsars, X-ray binaries, magnetars, extreme scattering events, interstellar scintillation, radio supernovae, and orphan afterglows of gamma-ray bursts. In addition, it will allow us to probe unexplored regions of parameter space where new classes of transient sources may be detected. In this paper we review the known radio transient and variable populations and the current results from blind radio surveys. We outline a comprehensive program based on a multi-tiered survey strategy to characterise the radio transient sky through detection and monitoring of transient and variable sources on the ASKAP imaging timescales of 5 s and greater. We also present an analysis of the expected source populations that we will be able to detect with VAST.
Genetic disturbances in folate metabolism may increase risk for congenital heart defects. We examined the association of heart defects with four polymorphisms in folate-related genes (methylenetetrahydrofolate reductase (MTHFR) c.677C > T, MTHFR c.1298A > C, methionine synthase reductase (MTRR) c.66A > G, and reduced folate carrier (SLC19A1) c.80A > G) in a case–control study of children (156 patients, 69 controls) and mothers of children with heart defects (181 patients, 65 controls), born before folic acid fortification. MTRR c.66A > G in children modified odds ratios for overall heart defects, specifically ventricular septal defect and aortic valve stenosis (p-value below 0.05). The 66GG and AG genotypes were associated with decreased odds ratios for heart defects (0.42, 95% confidence interval (0.18–0.97) and 0.39 (0.18–0.84), respectively). This overall association was driven by decreased risk for ventricular septal defect for 66GG and AG (odds ratio 0.32 (0.11–0.91) and 0.25 (0.09–0.65)) and decreased odds ratio for aortic valve stenosis for 66AG (0.27 (0.09–0.79)). The association of ventricular septal defect and 66AG remained significant after correction for multiple testing (p = 0.0044, multiple testing threshold p = 0.0125). Maternal MTHFR 1298AC genotype was associated with increased odds ratio for aortic valve stenosis (2.90 (1.22–6.86), p = 0.0157), but this association did not meet the higher multiple testing threshold. No association between MTHFR c.677C > T or SLC19A1 c.80A > G and heart defect risk was found. The influence of folate-related polymorphisms may be specific to certain types of heart defects; larger cohorts of mothers and children with distinct sub-classes are required to adequately address risk.