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Our understanding of the complex relationship between schizophrenia symptomatology and etiological factors can be improved by studying brain-based correlates of schizophrenia. Research showed that impairments in value processing and executive functioning, which have been associated with prefrontal brain areas [particularly the medial orbitofrontal cortex (MOFC)], are linked to negative symptoms. Here we tested the hypothesis that MOFC thickness is associated with negative symptom severity.
This study included 1985 individuals with schizophrenia from 17 research groups around the world contributing to the ENIGMA Schizophrenia Working Group. Cortical thickness values were obtained from T1-weighted structural brain scans using FreeSurfer. A meta-analysis across sites was conducted over effect sizes from a model predicting cortical thickness by negative symptom score (harmonized Scale for the Assessment of Negative Symptoms or Positive and Negative Syndrome Scale scores).
Meta-analytical results showed that left, but not right, MOFC thickness was significantly associated with negative symptom severity (βstd = −0.075; p = 0.019) after accounting for age, gender, and site. This effect remained significant (p = 0.036) in a model including overall illness severity. Covarying for duration of illness, age of onset, antipsychotic medication or handedness weakened the association of negative symptoms with left MOFC thickness. As part of a secondary analysis including 10 other prefrontal regions further associations in the left lateral orbitofrontal gyrus and pars opercularis emerged.
Using an unusually large cohort and a meta-analytical approach, our findings point towards a link between prefrontal thinning and negative symptom severity in schizophrenia. This finding provides further insight into the relationship between structural brain abnormalities and negative symptoms in schizophrenia.
The stellar occultation technique is a powerful tool to study distant small solar system bodies. Currently, around 2 500 trans-neptunian objects (TNOs) and Centaurs are known. With the astrometry from Gaia and large surveys like the Large Synoptic Survey Telescope (LSST), accurate predictions of occultation events will be available to tens of thousands of TNOs and Centaurs and boost the knowledge of the outer solar system.
Hypervelocity stars (HVSs) are characterized by a total velocity in excess of the Galactic escape speed, and with trajectories consistent with coming from the Galactic Centre. We apply a novel data mining routine, an artificial neural network, to discover HVSs in the TGAS subset of the first data release of the Gaia satellite, using only the astrometry of the stars. We find 80 stars with a predicted probability >90% of being HVSs, and we retrieved radial velocities for 47 of those. We discover 14 objects with a total velocity in the Galactic rest frame >400 km s−1, and 5 of these have a probability >50% of being unbound from the Milky Way. Tracing back orbits in different Galactic potentials, we discover 1 HVS candidate, 5 bound HVS candidates, and 5 runaway star candidates with remarkably high velocities, between 400 and 780 km s−1. We wait for future Gaia releases to confirm the goodness of our sample and to increase the number of HVS candidates.
Stellar occultations are a unique technique to access physical characteristics of distant solar system objects from the ground. They allow the measure of the size and the shape at kilometric level, the detection of tenuous atmospheres (few nanobars), and the investigation of close vicinity (satellites, rings) of Transneptunian objects and Centaurs. This technique is made successful thanks to accurate predictions of occultations. Accuracy of the predictions depends on the uncertainty in the position of the occulted star and the object's orbit. The Gaia stellar catalogue (Gaia Collaboration (2017)) now allows to get accurate astrometric stellar positions (to the mas level). The main uncertainty remains on the orbit. In this context, we now take advantage of the NIMA method (Desmars et al.(2015)) for the orbit determination and of the Gaia DR1 catalogue for the astrometry. In this document, we show how the orbit determination is improved by reducing current and some past observations with Gaia DR1. Moreover, we also use more than 45 past positive occultations observed in the 2009-2017 period to derive very accurate astrometric positions only depending on the position of the occulted stars (about few mas with Gaia DR1). We use the case of (10199) Chariklo as an illustration. The main limitation lies in the imprecision of the proper motions which is going to be solved by the Gaia DR2 release.
This study investigated the emission of subaquatic noise from recreational tourism motorboats, schooners and a sea-bottom mounted water pump. Analyses demonstrated alterations in several whistle (IF: t = 2.42, P = 0.015; FF: t = −2.22, P = 0.025) and calls patterns (MIF: t = −3.13, P = 0.001; MAF: t = −3.49, P = 0.0005; FD: t = −2.21, P = 0.027; D: t = 2.89, P = 0.004), caused primarily by motorboats. Duration of clicks was also modified (D: t = −3.85, P = 0.0001), mainly by the water pump. The frequency range of all noises (0.43–35.8 kHz) overlaps that used by dolphins (1–48 kHz), causing sound emissions changes, with a considerable increase in number of whistles and a reduction in clicks trains. These changes may be a strategy developed by these dolphins to overcome the noise band. Mitigation measures, such as boating regulations and environmental education for the local community, boaters and tourists are needed to conserve the species. The Guiana dolphin population is apparently already suffering, evidenced by diminished residence time and reduced number of individuals entering the inlet during the presence of pleasure craft.
The study aimed to subtype patients with schizophrenia on the basis of social cognition (SC), and to identify cut-offs that best discriminate among subtypes in 809 out-patients recruited in the context of the Italian Network for Research on Psychoses.
A two-step cluster analysis of The Awareness of Social Inference Test (TASIT), the Facial Emotion Identification Test and Mayer–Salovey–Caruso Emotional Intelligence Test scores was performed. Classification and regression tree analysis was used to identify the cut-offs of variables that best discriminated among clusters.
We identified three clusters, characterized by unimpaired (42%), impaired (50.4%) and very impaired (7.5%) SC. Three theory-of-mind domains were more important for the cluster definition as compared with emotion perception and emotional intelligence. Patients more able to understand simple sarcasm (⩾14 for TASIT-SS) were very likely to belong to the unimpaired SC cluster. Compared with patients in the impaired SC cluster, those in the very impaired SC cluster performed significantly worse in lie scenes (TASIT-LI <10), but not in simple sarcasm. Moreover, functioning, neurocognition, disorganization and SC had a linear relationship across the three clusters, while positive symptoms were significantly lower in patients with unimpaired SC as compared with patients with impaired and very impaired SC. On the other hand, negative symptoms were highest in patients with impaired levels of SC.
If replicated, the identification of such subtypes in clinical practice may help in tailoring rehabilitation efforts to the person's strengths to gain more benefit to the person.
Gamma-ray burst host galaxies are deficient in molecular gas, and show anomalous metal-poor regions close to GRB positions. Using recent Australia Telescope Compact Array (ATCA) Hi observations we show that they have substantial atomic gas reservoirs. This suggests that star formation in these galaxies may be fuelled by recent inflow of metal-poor atomic gas. While this process is debated, it can happen in low-metallicity gas near the onset of star formation because gas cooling (necessary for star formation) is faster than the Hi-to-H2 conversion.
Dobrava-Belgrade virus (DOBV) is the most pathogenic hantavirus in Europe with a case-fatality rate of up to 12%. To detect changes in risk for humans, the prevalence of antibodies to DOBV has been monitored in a population of Apodemus flavicollis in the province of Trento (northern Italy) since 2000, and a sudden increase was observed in 2010. In the 13-year period of this study, 2077 animals were live-trapped and mean hantavirus seroprevalence was 2·7% (s.e. = 0·3%), ranging from 0% (in 2000, 2002 and 2003) to 12·5% (in 2012). Climatic (temperature and precipitation) and host (rodent population density, rodent weight and sex, and larval tick burden) variables were analysed using Generalized Linear Models and multi-model inference to select the best model. Climatic changes (mean annual precipitation and maximum temperature) and individual body mass had a positive effect on hantavirus seroprevalence. Other possible drivers affecting the observed pattern need to be studied further.
Tondiite, with the simplified formula
Cu3Mg(OH)6Cl2, occurs as a rare
supergene mineral in a phonolitic tephrite from the type locality, Vesuvius
volcano, Italy, as well as associated with haydeeite in the Santo Domingo
Mine, Arica Province, Chile. It is emerald green to bright green in colour
and occurs in irregularly shaped crystals, often with stepped faces. Its
calculated density is 3.503 g cm−3. Tondiite crystallizes with
the herbertsmithite structure type, space group Rm. Lattice parameters are a = 6.8377(7) Å
and c = 14.088(2)Å for the holotype material. The
c parameter may vary with Mg/Cu ratio and the presence
of impurity atoms. The five strongest lines in the calculated powder
diffraction pattern are [d in
2.764(100)(112 3), 2.266(54)(024),
tondiite crystals have been examined by single-crystal X-ray diffraction and
by electron microprobe analysis. The observed Mg content ranges between 0.6
and 0.7 atoms per formula unit. The structural role of Mg is discussed.
We report on follow-up observations of 20 short-duration gamma-ray bursts
(T90 < 2s) performed in
with the Gamma-Ray Burst Optical Near-Infrared Detector (GROND) between mid-2007 and the
end of 2010. This is the most homogeneous and comprehensive data set on GRB afterglow
observations of short bursts. In three cases, GROND was on target within less than 10 min
after the trigger, leading to the discovery of the afterglow of GRB 081226A and its faint
underlying host galaxy. In addition, GROND was able to image the optical afterglow and
follow the light curve evolution in five further cases: GRBs 090305, 090426, 090510,
090927, and 100117A. Three of the aforementioned six bursts with optical light curves show
a break: GRBs 090426 and 090510 as well as GRB 090305. For GRB 090927, no break is seen in
the optical/X-ray light curve until about 150 ks/600 ks after the burst. A decay slope of
the optical afterglow of GRB 100117A could be measured. Using these data supplemented by
about ten events taken from the literature, we compare the jet half-opening angles of long
and short bursts. We find a tentative evidence that short bursts have wider opening angles
than long bursts. However, the statistics are still very poor and follow-up observations
of these events are therefore very important to gain as much observational data as
Long gamma-ray bursts (GRBs) pinpoint star-forming galaxies as they are linked to the
deaths of massive stars. In most cases, these galaxies have been found to be blue,
sub-luminous and of low-metallicity. However, our recent survey have demonstrated that a
sizeable fraction of GRBs reside in massive, dusty and star-forming extremely red objects
(EROs, (R − K)AB > 3.5).
The most remarkable case is the host of GRB 080207, one of the reddest galaxies ever
associated with a GRB. This discovery suggests that at least a fraction of GRB afterglows
trace a subpopulation of massive starburst galaxies, which are markedly different from the
most studied blue, sub-luminous and compact GRB host galaxies.
We present preliminary results for the estimation of barium [Ba/Fe], and strontium [Sr/Fe], abundances ratios using medium-resolution spectra (1–2 Å). We established a calibration between the abundance ratios and line indices for Ba and Sr, using multiple regression and artificial neural network techniques. A comparison between the two techniques (showing the advantage of the latter), as well as a discussion of future work, is presented.
Multi-slice computed tomography (MSCT) has proven in
several studies to have a high diagnostic accuracy for the detection
or exclusion of coronary artery disease. A major concern with coronary
MSCT, however, is the associated radiation exposure of patients.
Recent studies suggest that use of a 64-slice scanner is associated
with a non-negligible lifetime attributable risk of cancer. Several
strategies can be used to reduce patient exposure in coronary MSCT.
The purpose of this multicenter study was to investigate the effects
of the adjustment of tube voltage and current on radiation dose
and image interpretability. MSCT with retrospective ECG gating was performed
in 315 patients. The dose-length product (DLP) in the patients enrolled
with the dose reduction protocol resulted in a 36% overall reduction
in the mean radiation dose (911 ± 289 mGy.cm) compared with the
standard protocol (1427 ± 226 mGy.cm, p < 0.001).
Nevertheless, image interpretability was maintained. This study
on coronary MSCT demonstrates that the radiation dose can be significantly reduced
by parameter optimization, with maintained image interpretability.
To evaluate the efficacy of the Santiago treatment protocol for benign paroxysmal positional vertigo of the posterior semicircular canal, to analyse recurrence and to establish prognostic factors.
Material and methods:
Four hundred and twelve patients with unilateral benign paroxysmal positional vertigo of the posterior semicircular canal were treated with the Semont manoeuvre and, if symptoms did not resolve, successive application of three Epley manoeuvres plus Brandt–Daroff exercises.
Symptoms resolved in 404 patients (98.1 per cent); a single Semont manoeuvre was sufficient in 334 (81.2 per cent). Aetiology had no impact on resolution of symptoms or number of manoeuvres required. The estimated likelihood of recurrence was 14 per cent in the first year and 27 per cent after 10 years. The only factor indicating a worse prognosis was recurrence.
In unilateral benign paroxysmal positional vertigo of the posterior semicircular canal, the above treatment protocol cured 98 per cent of patients. More than half of recurrences occurred in the first year. None of the analysed factors increased the likelihood of recurrence.
Hydrogenated microcrystalline silicon (μc-Si:H) thin films have been obtained by plasma decomposition of SiF4-H2-He mixtures at low temperature (120 °C). The size of crystalline grain and their volume fraction with respect to the amorphous phase have been found dependent on the r.f. power as evaluated by grazing incidence X-ray diffraction, microRaman and ellipsometry measurements. Chemical and electrical properties change according to the microcrystallinity. Pure and/or highly microcrystalline silicon has been obtained at temperature and r.f. power as low as 120 °C and 15 Watt.
Two distinct measles outbreaks, unrelated from the epidemiological point of view but caused by genetically related strains, occurred in the Friuli Venezia Giulia region of northeastern Italy. Forty-two cases were reported during the period April–May 2008. In the first outbreak the index case was a teacher who introduced the virus into the Pordenone area, involving eight adolescents and young adults. The other concomitant outbreak occurred in the city of Trieste with 33 cases. The containment of the epidemics can be explained by the high MMR vaccine coverage in an area where the first dose was delivered to 93·4% and the second dose to 88·3% of the target children. Phylogenetic analysis of 14 measles virus strains showed that they belonged to a unique D4 genotype indistinguishable from the MVs/Enfield.GBR/14.07 strain, probably introduced from areas (i.e. Piedmont and Germany) where this genotype was present or had recently caused a large epidemic.
We report surface extended X-ray absorption edge fine structure (SEXAFS) studies of the early stages of Schottky barrier formation. Results will be presented for aluminum, silver and palladium on Si(111) 7 × 7 in the range from ⅓ monolayer to five monolayers. The SEXAFS signal reveals the local structure around the metal atoms in terms of bond lengths and coordination numbers. Complex ordered and disordered surface structures are observed ranging from weak reaction between the components (e.g. silver clusters on silicon) to strong reaction (e.g. Pd2Si formation). At elevated temperatures the Ag–Si interface is particularly interesting and consists of a well-defined ordered interface layer (√3 × √3 Ag on Si(111)) with silver clusters growing on top. While most other surface structural techniques fail to yield complete information the power of SEXAFS as a local structural technique becomes most apparent for such complex systems. Structure determinations for some metalsemiconductor interfaces will be presented.
We report on the nature of emitting states in two different quaterthiophenes: the unsubstituted quaterthiophenes (T4) and a bridged T4 (T4B), where the bridging have been realized by introducing a second bond between the two central thiophene rings. The effect of the chemical bridging on the photophysics of these compounds have been studied via photoluminescence measurements under hydrostatic pressure, which permit to clarify the influence of interchain coupling, conformational effects and intrachain structural changes on the optical properties.