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Some of the high luminosity stars in our Galaxy are surrounded by planetary-like nebulae formed by material ejected from the central star. The most interesting case is that of the ring nebula PK 289-0° 1 around the P Cygni star AG Car. Long slit spectroscopy shows that nitrogen is overabundant and oxygen underabundant in the nebula. The Hα/[NII] ratio is lower in the nebula with respect to the surrounding H II region, possibly as a result of the N overabundance in the stellar wind. The emission line peak separation confirms a model of a distorted spherical shell expanding at 66 km s−1. The scattered star's spectrum is observable near the star, suggesting the presence of circumstellar dust grains. A nebular mass of at least 2.7 M⊙ is derived. While the nebula in the Hα imagery reveals the ring-like shape with many structures, in the blue it is much fainter and smoother. No nebular emission was detected in the JHK bands, suggesting a low dust temperature.
If the grains in pre-collapsing clouds are due to the contribution of winds from previous generations of stars and supernovae ejecta, they already contain a fraction if not all, of the heavy elements. The far infrared spectrum of Bok globules, which are at relatively early contraction stages, has been attributed to dusty material.
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.
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.
Reversible actuation strains in excess of 2% in the sheet direction and over 300% in the thickness direction have been produced by single wall carbon nanotube mats when electrochemically charged to +1.5V (vs. SCE) in aqueous sodium chloride solution. The observed strains represent a ten-fold increase over that previously reported for carbon nanotube actuators, and is considerably larger than that achievable with polymer ferroelectric actuators. The enhanced actuator strains result from a new mechanism of electrochemically induced “pnuematic actuation” where high pressure gas forms within the porous structure of the nanotube mat causing partial delamination and swelling. An erasable “memory” effect was also observed for pneumatic actuation driven by hydrogen gas evolution/storage in the nanotube electrodes.
Bismuth doped SnO2 films with reproducible optical and electronic properties were deposited by spray-pyrolysis on quartz and glass substrates.Deposition temperatures in the range 300°C–360°C were selected and resistivity values in the range 104−1011Ω/square were obtained. Scanning Electron Microscope (SEM) analysis and X-ray diffractometry showed that samples grown at low temperature are amorphous, while at higher deposition temperature the material structure becomes microcrystalline. The spectral transmittance of the films was measured in the UV-VIS range. The absorption coefficients were interpreted to give values of both direct and indirect band gap. The slope of Tauc's plot, which is commonly related to the degree of disorder in the material, confirmed the SEM observations. Conduction mechanisms were also studied through resistivity measurements as a function of deposition temperature. Results obtained for undoped tin oxide were also investigated for comparison.
We retrospectively studied patients diagnosed with P. aeruginosa bloodstream infections (BSIs) in two Italian university hospitals. Risk factors for the isolation of multidrug-resistant (MDR) or non-MDR P. aeruginosa in blood cultures were identified by a case-case-control study, and a cohort study evaluated the clinical outcomes of such infections. We identified 106 patients with P. aeruginosa BSI over the 2-year study period; 40 cases with MDR P. aeruginosa and 66 cases with non-MDR P. aeruginosa were compared to 212 controls. Independent risk factors for the isolation of MDR P. aeruginosa were: presence of central venous catheter (CVC), previous antibiotic therapy, and corticosteroid therapy. Independent risk factors for non-MDR P. aeruginosa were: previous BSI, neutrophil count <500/mm3, urinary catheterization, and presence of CVC. The 21-day mortality rate of all patients was 33·9%. The variables independently associated with 21-day mortality were presentation with septic shock, infection due to MDR P. aeruginosa, and inadequate initial antimicrobial therapy.
Steel slag is a steel-making industry by-product, currently used for
several applications in substitution of non-renewable natural resources
(e.g., crushed stone and sand). The major reason for conducting
this study at CST ArcelorMittal Brasil was to verify if any of the current
uses of LD and NP slag presented significant risks to the environment
and/or human health.
Earlier analysis of the Italian population showed patterns of genetic
differentiation that were
interpreted as being the result of population settlements going back to
pre-Roman times. DNA
disease mutations may be a powerful tool in further testing this hypothesis
since the analysis of
diseased individuals can detect variants too rare to be resolved in normal
individuals. We present
data on the relative frequencies of 60 cystic fibrosis (CF) mutations in
Italy and the geographical
distribution of the 12 most frequent CF mutations screened in 3492 CF
chromosomes originating in
13 Italian regions. The 12 most frequent mutations characterize about 73%
of the Italian CF
chromosomes. The most common mutation, ΔF508, has an average frequency
51%, followed by
N1303K and G542X, both with average frequencies around 5%. Multivariate
analyses show that the
relative frequencies of CF mutations are heterogeneous among Italian regions,
and that this
heterogeneity is weakly correlated with the geographical pattern of non-DNA
markers. The northern regions are well differentiated from the central-southern
regions and within
the former group the western and eastern regions are remarkably distinct.
Moreover, Sardinia shows
the presence of mutation T338I, which seems absent in any other European
CF chromosome. The
north-western regions of Italy, characterized by the mutation 1717-1G→A,
under Celtic influence, while the north-east regions, characterized by
mutations R1162X, 2183AA→G and
7115G→A, were under the influence of the Venetic culture.
A standardised clinical examination which focused on neurological soft signs (NSS) was used by a neurologist blind to diagnosis to assess the presence of neurological soft signs. A comparison of NSS score was made among three groups of subjects consisting of 58 DSM–III schizophrenics, 31 of their healthy first-degree relatives and 38 normal controls. The schizophrenic group had significantly higher NSS total scores than normal controls but did not differ significantly from their first-degree relatives' group. The relatives' group showed higher NSS total scores than did normal controls although to a lesser extent than schizophrenics.
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