GRB minimum variability timescale with Insight-HXMT and Swift: implications for progenitor models, dissipation physics and GRB classifications

The dissipation process of GRB prompt emission is still unknown. Study of temporal variability may provide a unique way to discriminate the imprint of the inner engine activity from geometry and propagation related effects. We define the minimum variability timescale (MVT) as the shortest duration of individual pulses that shape a light curve for a sample of GRBs and test correlations with peak luminosity, Lorentz factor, and jet opening angle. We compare these correlations with predictions from recent numerical simulations for a relativistic structured -- possibly wobbling -- jet and assess the value of MTV as probe of prompt-emission physics. We used the peak detection algorithm mepsa to identify the shortest pulse within a GRB time history and estimate its full width half maximum (FWHM). We applied this framework to two sets of GRBs: Swift (from 2005 to July 2022) and Insight-HXMT (from June 2017 to July 2021, including 221009A). We then selected 401 GRBs with measured z to test for correlations. On average short GRBs have significantly shorter MVT than long GRBs. The MVT distribution of short GRBs with extended emission such as 060614 and 211211A is compatible only with that of short GRBs. This provides a new clue on the progenitor's nature. The MVT for long GRBs anticorrelates with peak luminosity. We confirm the anticorrelation with the Lorentz factor and find a correlation with the jet opening angle as estimated from the afterglow, along with an inverse correlation with the number of pulses. The MVT can identify the emerging putative new class of long GRBs that are suggested to be produced by compact binary mergers. For otherwise typical long GRBs, the different correlations between MVT and peak luminosity, Lorentz factor, jet opening angle, and number of pulses can be explained within the context of structured, possibly wobbling, weakly magnetised relativistic jets. (summarised)Comment: 18 pages, 15 figures, accepted by A&

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an immune-mediated chronic cholestatic liver disease with a slowly progressive course. Without treatment, most patients eventually develop fibrosis and cirrhosis of the liver and may need liver transplantation in the late stage of disease. PBC primarily affects women (female preponderance 9–10:1) with a prevalence of up to 1 in 1,000 women over 40 years of age. Common symptoms of the disease are fatigue and pruritus, but most patients are asymptomatic at first presentation. The diagnosis is based on sustained elevation of serum markers of cholestasis, i.e., alkaline phosphatase and gamma-glutamyl transferase, and the presence of serum antimitochondrial antibodies directed against the E2 subunit of the pyruvate dehydrogenase complex. Histologically, PBC is characterized by florid bile duct lesions with damage to biliary epithelial cells, an often dense portal inflammatory infiltrate and progressive loss of small intrahepatic bile ducts. Although the insight into pathogenetic aspects of PBC has grown enormously during the recent decade and numerous genetic, environmental, and infectious factors have been disclosed which may contribute to the development of PBC, the precise pathogenesis remains enigmatic. Ursodeoxycholic acid (UDCA) is currently the only FDA-approved medical treatment for PBC. When administered at adequate doses of 13–15 mg/kg/day, up to two out of three patients with PBC may have a normal life expectancy without additional therapeutic measures. The mode of action of UDCA is still under discussion, but stimulation of impaired hepatocellular and cholangiocellular secretion, detoxification of bile, and antiapoptotic effects may represent key mechanisms. One out of three patients does not adequately respond to UDCA therapy and may need additional medical therapy and/or liver transplantation. This review summarizes current knowledge on the clinical, diagnostic, pathogenetic, and therapeutic aspects of PBC

Protein-water and water-water long-time relaxations in protein hydration water upon cooling—A close look through density correlation functions

We report results on the translational dynamics of the hydration water of the lysozyme protein upon cooling obtained by means of molecular dynamics simulations. The self van Hove functions and the mean square displacements of hydration water show two different temperature activated relaxation mechanisms, determining two dynamic regimes where transient trapping of the molecules is followed by hopping phenomena to allow to the structural relaxations. The two caging and hopping regimes are different in their nature. The low-temperature hopping regime has a time scale of tenths of nanoseconds and a length scale on the order of 2–3 water shells. This is connected to the nearest-neighbours cage effect and restricted to the supercooling, it is absent at high temperature and it is the mechanism to escape from the cage also present in bulk water. The second hopping regime is active at high temperatures, on the nanoseconds time scale and over distances of nanometers. This regime is connected to water displacements driven by the protein motion and it is observed very clearly at high temperatures and for temperatures higher than the protein dynamical transition. Below this temperature, the suppression of protein fluctuations largely increases the time-scale of the protein-related hopping phenomena at least over 100 ns. These protein-related hopping phenomena permit the detection of translational motions of hydration water molecules longly persistent in the hydration shell of the protein

Protein hydration water: Focus on low density and high density local structures upon cooling

We report results about the structure of protein hydration water upon cooling compared to bulk water. We focus on the analysis of the local structure through order parameters: the tetrahedral order parameter q and a recently introduced parameter . Both parameters show that, similarly to bulk water, protein hydration water is a mixture of two liquids already at ambient conditions. These liquids are a low density liquid (LDL) characterized by a more tetrahedral-ordered local structure and a high density liquid (HDL) that is more distorted. Protein hydration water has a higher concentration of HDL with respect to LDL if compared to the bulk case upon cooling. The two water populations of hydration water are also less sensitive to temperature variations with respect to bulk water. The presence of the protein affects the structure of hydration water that is locally more distorted than bulk water. Both the parameters display a two-liquid picture of hydration water. Correlations between the two parameters are also investigated. In spite of the differences found in hydration water with respect to the bulk the bimodal structure is importantly preserved

Slow Dynamics of Biological Water

Water hydrating biomolecules shows a more complex dynamical behavior when compared to the bulk. Its translational slow dynamics can be described by two mechanisms characterized by two well distinct time scales. One mechanism is the α -relaxation typical of supercooled bulk water and other glass forming liquids. Upon cooling, this relaxation shows a fragile-to-strong crossover due to the activation of hopping phenomena which permits to the water molecules in the hydration layer to escape from nearest neighbors cage. The second mechanism is a much slower relaxation that is present only in hydration water and it is coupled with the biomolecule dynamics. This long-relaxation shows upon cooling a strong-to-strong crossover in coincidence with the well-known Protein Dynamical Transition. Structural rearrangements of biomolecules can trap hydration water molecules over length-scale larger than nearest neighbors distances. This causes a new hopping regime specific only of hydration water and already active at high temperature

THE CHILDREN’S COPING STRATEGIES CHECKLIST-REVISION1: A VALIDATION STUDY IN THE ITALIAN POPULATION

This study was aimed to validate the Italian version of the Children’s Coping Strategies Checklist-Revision1 (CCSC-R1; Ayers & Sandler, 1999). Seven hundred and forty-seven youngsters (50.5% boys) from two age groups (children: aged 9-10; early adolescents: aged 11-14) participated in the study. Dimensionality of the CCSC-R1 was explored by means of confirmatory factor analyses and testing alternative models. The scale internal consistency and invariance over age and gender were examined, as well as gender- and age-related differences in the CCSC-R1 scores. The scale concurrent validity was explored by investigating the associations of the CCSC-R1 dimensions with forms of involvement in bullying and social status among peers in a subsample (N = 255). Analyses provided evidence that a five-factor structure model was most effective. Internal validity of the scale and its partial scalar invariance over age and gender were confirmed. Several of the CCSC-R1 dimensions were associated with involvement in bullying and social status in the expected directions

Slow dynamics of supercooled trehalose hydration water in comparison with bulk water

Trehalose aqueous solutions are relevant in many technological applications, for example in cryopreservation of biomolecules. It is known that the presence of this disaccharide is able to slow down the dynamics of nearby water molecules and to modify their spatial rearrangement, nevertheless, a complete understanding of the properties of water-trehalose solutions and of trehalose cryoprotective properties is still lacking. Here we discuss recent molecular dynamics simulation results of water-trehalose solutions, performed at different temperatures upon cooling, and we compare the results with the behavior of the bulk phase. In particular we focus on the dynamical properties of hydration water, i.e., the water molecules in the hydration shell of the disaccharide. Hydration water shows a sub-diffusive behavior with respect to bulk water, the same structural relaxation typical of glass formers liquids, albeit slightly slower than in the bulk, and an additional relaxation process at longer timescales completely absent in the bulk. The analysis of hydrogen bond autocorrelation functions allows to connect the structural and long relaxation processes of hydration water to the dynamics of two distinct population of hydrogen bonds in the system, the water-water and water-trehalose hydrogen bonds

Postpartum depressive symptoms as a linking mechanism between maternal sleep and parenting stress: the conditional indirect effect by social support

Research has shown the associations between maternal depressive symptoms, sleep difficulties, and parenting competences and supports the importance of social support during the post-partum period. Nevertheless, the investigation of sleep difficulties as antecedents of depressive symptoms and parenting and the exploration of perceived social support in these links is a new research topic. Using a sample of 95 mothers, the present study explored: the effects of maternal sleep difficulties on parenting stress through the mediation of depressive symptoms; and the protective role of social support in these associations. Results suggested indirect effects of maternal sleep difficulties on parenting stress through depressive symptoms that were conditioned by social support. Implications for clinical care are discussed

Parenting Stress and Posttraumatic Stress Symptoms after Childbirth. A Longitudinal Study.

The aim of this study was to analyze the relationship between Parenting Stress and Posttraumatic Stress Symptoms (PTSS) to verify whether specific post-partum symptoms of Intrusion, Avoidance and Hyperarousal contribute to explaining mothers’ stress in performance of parenting tasks. Our hypothesis was that the mothers’ posttraumatic post-partum symptoms at three months contribute to explain parenting stress (PSI) in raising children at 18 months The sample was of 53 mothers (mean age =30,92; SD= 4,63) followed from three months (T1) to eighteen months postpartum (T2). At T1 and at T2 the Perinatal posttraumatic Questionnaire and the Parenting Stress Index-SF were administered to evaluate traumatic post-partum symptoms (PTSS) and the stress of being parent. The data show that avoidance symptoms experienced in the first three months have a significant impact on parental distress in the long term; an impact which is stronger than the stress as parent present at three months. The perception of having a difficult child is sustained both by the hyperarousal symptoms and by the corresponding perception of having a difficult child present at three months