The X-ray and gamma-ray sky - Temporal, spectral and triangulation techniques for the characterization and localization of sources in High Energy Astrophysics

The X-ray and gamma-ray sky hides some of the most energetic events we can observe, and with them the struggle to shed some light onto the most extreme conditions of matter and the fabric of space-time. Low-Mass X-ray Binaries (LMXBs) are binary systems in which a compact object accretes matter from a companion star of mass less than 1 solar mass. The two companions interact with exchanges of matter that flows from the companion star towards the compact object, through Roche lobe overflow, where it is accreted with consequent emission of energy, visible mostly in the X-ray band. XTE J1810-189 is a LMXB hosting a neutron star (NS). I analyzed data of the NICER observatory from its 2020 outburst. The analysis revealed typical characteristics of Very-Faint X-ray Transients, systems characterized by peak X-ray luminosities of around 1036 erg/s. I could detect a disc component and a partially obscuring corona, while no NS direct component could be found. The source showed very little spectral evolution. MAXI J1834-021 is a new X-ray transient that shows features of a LMXB but with no certainty about the nature of the central accretor. The source remains in a low luminosity state, possibly performing a Failed-Transition outburst. From the spectral features, I could identify an accretion disc component and derive a lower limit of 6.5 gravitational radii on its truncation radius. The timing analysis shows features, such as Quasi-Periodic Oscillations, at around 2 Hz, compatible with a Black Hole Transient in a hard state. Accreting Millisecond X-ray Pulsars (AMXPs) are a subclass of NS LMXBs in which the NS shows X-ray pulsations at periods shorter than 10 milliseconds. In these systems, the X-ray emission comes from accretion of matter at the magnetic poles, modulated at the NS spin period. They are thought to be the progenitors of isolated, rotation-powered millisecond pulsars (MSPs). IGR J17591-2342 is an AMXP that went in outburst in 2018. The source underwent a canonical AMXP outburst: a low-luminosity state, with an identifiable NS emission and a region of Inverse Compton Scattering processes, often obscuring the direct NS emission. By taking into consideration the hydrogen column density, I could estimate the distance of the source, at around 7.2 kpc, which is consistent with the one previously estimated with the temporally-resolved spectral analysis of a type-I X-ray burst. Transitional Millisecond Pulsars (tMSPs) are defined as MSPs in binary systems that are observed to perform at least one transition between a rotation-powered state and an accretion-powered state. tMSPs in their sub-luminous state showed a gamma-ray emission several times higher than in the rotation-powered state. Therefore, establishing a connection between a known X-ray source and an unidentified gamma-ray source is one step towards the classification of the source as a tMSP. CXOU J1109 is a candidate tMSP. I studied the Fermi/LAT gamma-ray counterpart of J1109, in order to search for a compatible localization and study the spectral characteristics of the gamma-ray source. The background model resulted into around 180 sources. The new localization, calculated with 15 years of Fermi/LAT data, is compatible at the 95% confidence level with the X-ray source, with a detection significance of around 5 sigma, and improves the current cataloged position. The gamma-ray band also shows the most energetic events ever detected: Gamma-Ray Bursts (GRBs). As member of the HERMES collaboration, I worked on the development of a software to simulate the capabilities of the mission, based on a constellation of nano-satellites with the aim of accurately localizing gamma-ray bursts. The HERMES mission aims to study GRBs and provide quick and accurate localization through triangulation techniques. From the simulated data, we can test the spectral properties and the algorithm for the determination of the position of the GRB in the sky

Estimated insulin sensitivity, cardiovascular risk, and hepatic steatosis after 12 years from the onset of T1D

Aim To test the hypothesis that intensive insulin treatment and optimal glycaemic control are not fully protective against reduction of insulin sensitivity in children with type 1 diabetes.Material and methods Cohort study of 78 normal-weight patients with prepubertal onset (T (0)) and follow-up waves at 1 (T (1)), 5 (T (5)), 10 (T (10)), and 12 (T (12)) years; matched for age and sex to 30 controls at T (12). Estimated insulin sensitivity (eIS) by three formulae; ultrasound evaluation of para and perirenal fat thickness; hepatic steatosis (HS); carotid intima media thickness (cIMT) at T (12).Results At T12, the 36 patients (46%) who had constantly or prevalently haemoglobin A1c (HbA1c) < 58 mmol/l during follow-up showed better eIS indexes (p = 0.049 to <0.0001); lipid profile (p = 0.042 to <0.0001), reduced fat mass (p = 0.012) and required lower insulin dose (p = 0.032) than the 42 patients (54%) with HbA1c >= 58 at T12. Patients (N = 25) with eIS(EDC) < 8.77 mg kg(-1) min(-1) showed higher cIMT (p < 0.0001). HS was found in 6 patients (similar to 8%). In patients and normal-weight controls, fat mass (p = 0.03), age (p = 0.03), cIMT (p = 0.05) predicted HS; eIS indexes (p from 0.04 to <0.0001) predicted cIMT. Body mass index, perirenal fat, fat mass, and triglycerides to high density lipoprotein cholesterol ratio were associated with eIS indexes (p from 0.03 to <0.0001).Conclusions Young T1D patients have reduced insulin sensitivity and higher cIMT. Adiposity, glucose, and lipid control over follow-up are likely to influence both. Enhanced adiposity seems of paramount relevance for the onset of HS in T1D patients alike in healthy youths

Indagini limnologiche nell\u27area antistante la Foce del Torrente San Bernardino (Sopralluoghi del 18-20 aprile 2011)

No abstract availabl

Does social cognition change? Evidence after 4 years from the Italian Network for Research on Psychoses

Background Deficits in social cognition (SC) are significantly related to community functioning in schizophrenia (SZ). Few studies investigated longitudinal changes in SC and its impact on recovery. In the present study, we aimed: (a) to estimate the magnitude and clinical significance of SC change in outpatients with stable SZ who were assessed at baseline and after 4 years, (b) to identify predictors of reliable and clinically significant change (RCSC), and (c) to determine whether changes in SC over 4 years predicted patient recovery at follow-up. Methods The reliable change index was used to estimate the proportion of true change in SC, not attributable to measurement error. Stepwise multiple logistic regression models were used to identify the predictors of RCSC in a SC domain (The Awareness of Social Inference Test [TASIT]) and the effect of change in TASIT on recovery at follow-up. Results In 548 participants, statistically significant improvements were found for the simple and paradoxical sarcasm of TASIT scale, and for the total score of section 2. The reliable change index was 9.8. A cut-off of 45 identified patients showing clinically significant change. Reliable change was achieved by 12.6% and RCSC by 8% of participants. Lower baseline TASIT sect. 2 score predicted reliable improvement on TASIT sect. 2. Improvement in TASIT sect. 2 scores predicted functional recovery, with a 10-point change predicting 40% increase in the probability of recovery. Conclusions The RCSC index provides a conservative way to assess the improvement in the ability to grasp sarcasm in SZ, and is associated with recovery

Accuracy of self-assessment of real-life functioning in schizophrenia

A consensus has not yet been reached regarding the accuracy of people with schizophrenia in self-reporting their real-life functioning. In a large (n=618) cohort of stable, community-dwelling schizophrenia patients we sought to: (1) examine the concordance of patients' reports of their real-life functioning with the reports of their key caregiver; (2) identify which patient characteristics are associated to the differences between patients and informants. Patient-caregiver concordance of the ratings in three Specific Level of Functioning Scale (SLOF) domains (interpersonal relationships, everyday life skills, work skills) was evaluated with matched-pair t tests, the Lin's concordance correlation, Somers' D, and Bland-Altman plots with limits of agreement (LOA). Predictors of the patient-caregiver differences in SLOF ratings were assessed with a linear regression with multivariable fractional polynomials. Patients' self-evaluation of functioning was higher than caregivers' in all the evaluated domains of the SLOF and 17.6% of the patients exceeded the LOA, thus providing a self-evaluation discordant from their key caregivers. The strongest predictors of patient-caregiver discrepancies were caregivers' ratings in each SLOF domain. In clinically stable outpatients with a moderate degree of functional impairment, self-evaluation with the SLOF scale can become a useful, informative and reliable clinical tool to design a tailored rehabilitation program

The interplay among psychopathology, personal resources, context-related factors and real-life functioning in schizophrenia: stability in relationships after 4 years and differences in network structure between recovered and non-recovered patients

Improving real-life functioning is the main goal of the most advanced integrated treatment programs in people with schizophrenia. The Italian Network for Research on Psychoses previously explored, by using network analysis, the interplay among illness-related variables, personal resources, context-related factors and real-life functioning in a large sample of patients with schizophrenia. The same research network has now completed a 4-year follow-up of the original sample. In the present study, we used network analysis to test whether the pattern of relationships among all variables investigated at baseline was similar at follow-up. In addition, we compared the network structure of patients who were classified as recovered at follow-up versus those who did not recover. Six hundred eighteen subjects recruited at baseline could be assessed in the follow-up study. The network structure did not change significantly from baseline to follow-up, and the overall strength of the connections among variables increased slightly, but not significantly. Functional capacity and everyday life skills had a high betweenness and closeness in the network at follow-up, as they had at baseline, while psychopathological variables remained more peripheral. The network structure and connectivity of non-recovered patients were similar to those observed in the whole sample, but very different from those in recovered subjects, in which we found few connections only. These data strongly suggest that tightly coupled symptoms/dysfunctions tend to maintain each other's activation, contributing to poor outcome in schizophrenia. Early and integrated treatment plans, targeting variables with high centrality, might prevent the emergence of self-reinforcing networks of symptoms and dysfunctions in people with schizophrenia

The interplay among psychopathology, personal resources, context-related factors and real-life functioning in schizophrenia: stability in relationships after 4 years and differences in network structure between recovered and non-recovered patients

Improving real-life functioning is the main goal of the most advanced integrated treatment programs in people with schizophrenia. The Italian Network for Research on Psychoses previously explored, by using network analysis, the interplay among illness-related variables, personal resources, context-related factors and real-life functioning in a large sample of patients with schizophrenia. The same research network has now completed a 4-year follow-up of the original sample. In the present study, we used network analysis to test whether the pattern of relationships among all variables investigated at baseline was similar at follow-up. In addition, we compared the network structure of patients who were classified as recovered at follow-up versus those who did not recover. Six hundred eighteen subjects recruited at baseline could be assessed in the follow-up study. The network structure did not change significantly from baseline to follow-up, and the overall strength of the connections among variables increased slightly, but not significantly. Functional capacity and everyday life skills had a high betweenness and closeness in the network at follow-up, as they had at baseline, while psychopathological variables remained more peripheral. The network structure and connectivity of non-recovered patients were similar to those observed in the whole sample, but very different from those in recovered subjects, in which we found few connections only. These data strongly suggest that tightly coupled symptoms/dysfunctions tend to maintain each other's activation, contributing to poor outcome in schizophrenia. Early and integrated treatment plans, targeting variables with high centrality, might prevent the emergence of self-reinforcing networks of symptoms and dysfunctions in people with schizophrenia

Building façades optimization at preliminary design stage for outdoor noise mitigation

Noise pollution is one of the main issues affecting the inhabitants of contemporary cities, and architects are among the ones that are asked to find innovative solutions to the problem. However, outdoor noise mitigation is tackled only at the final stages of the design. The present study explores the possibility of integrating optimized façades design for outdoor noise mitigation into the preliminary building design phases through performance based design. Analysis have been conducted on a case-study building located in Torino (IT) through Rhinoceros 3D models, Grasshopper algorithms and Pachyderm Acoustic Simulation plug-in. The optimization algorithm allowed testing 3600 different façade materials combination, in order to maximize the environmental noise mitigation. A reduction of 1.2 dB was obtained by the optimization of materials in compliance with realistic constraints that are present when designing a building façade. Results of further simulations proved that sound absorbing materials on the street pavement and at the ground floor of the building have negligible effects for receivers placed above the ground floor, while variations in balconies geometries have a significant effect

An Integrated Investigation of Atmospheric Gaseous Elemental Mercury Transport and Dispersion Around a Chlor-Alkali Plant in the Ossola Valley (Italian Central Alps)

We present the first assessment of atmospheric pollution by mercury (Hg) in an industrialized area located in the Ossola Valley (Italian Central Alps), in close proximity to the Toce River. The study area suffers from a level of Hg contamination due to a Hg cell chlor-alkali plant operating from 1915 to the end of 2017. We measured gaseous elemental Hg (GEM) levels by means of a portable Hg analyzer during car surveys between autumn 2018 and summer 2020. Moreover, we assessed the long-term dispersion pattern of atmospheric Hg by analyzing the total Hg concentration in samples of lichens collected in the Ossola Valley. High values of GEM concentrations (1112 ng m−3) up to three orders of magnitude higher than the typical terrestrial background concentration in the northern hemisphere were measured in the proximity of the chlor-alkali plant. Hg concentrations in lichens ranged from 142 ng g−1 at sampling sites located north of the chlor-alkali plant to 624 ng g−1 in lichens collected south of the chlor-alkali plant. A north-south gradient of Hg accumulation in lichens along the Ossola Valley channel was observed, highlighting that the area located south of the chlor-alkali plant is more exposed to the dispersion of Hg emitted into the atmosphere from the industrial site. Long-term studies on Hg emission and dispersion in the Ossola Valley are needed to better assess potential impact on ecosystems and human health

Comparison of γ-aminobutyric acid and biogenic amine content of different types of ewe’s milk cheese produced in Sardinia, Italy

The bioactive compounds γ-aminobutyric acid (GABA) and biogenic amines (BA), together with protein-free amino acids, were measured by high-performance liquid chromatography in ewe’s milk cheeses produced in Sardinia with different technological traits. The study included three types of cheese: Pecorino Sardo PDO, Pecorino and Casu Marzu. Farmhouse Casu Marzu and Pecorino showed GABA content (maximum levels: 1001.3 and 378.1 mg 100 g^–1 respectively) that had never been found so high in cheese before, suggesting that these types of cheese present ideal conditions to produce GABA. These two types of cheese also showed high levels of BA (their total maximum levels were 1035.7 and 288.0 mg 100 g^–1 respectively). Pearson correlation analysis detected significant correlation between GABA and the main BA present in the cheeses (tyramine, cadaverine and putrescine), suggesting that the factors affecting the production of GABA are the same as those influencing BA formation