Istituto Universitario Di Studi Superiori Di Pavia

About: Istituto Universitario Di Studi Superiori Di Pavia is a education organization based out in Pavia, Italy. It is known for research contribution in the topics: Pulsar & Neutron star. The organization has 162 authors who have published 566 publications receiving 22605 citations.

Xmm-newton slew survey observations of the gravitational wave event gw150914

Abstract: The detection of the first gravitational wave (GW) transient GW150914 prompted an extensive campaign of follow-up observations at all wavelengths. Although no dedicated XMM-Newton observations have been performed, the satellite passed through the GW150914 error region during normal operations. Here we report the analysis of the data taken during these satellite slews performed two hours and two weeks after the GW event. Our data cover 1.1 and 4.8 deg2 of the final GW localization region. No X-ray counterpart to GW150914 is found down to a sensitivity of 6 × 10−13 erg cm−2 s−1 in the 0.2–2 keV band. Nevertheless, these observations show the great potential of XMM-Newton slew observations for searching for the electromagnetic counterparts of GW events. A series of adjacent slews performed in response to a GW trigger would take 1.5 days to cover most of the typical GW credible region. We discuss this scenario and its prospects for detecting the X-ray counterpart of future GW detections.

Simplified seismic assessment of infilled RC frame structures

Abstract: Earthquake-induced structural damage, characterised by the exceedance of different damage states during ground shaking, is typically quantified using fragility curves generated through non-linear dynamic analyses often requiring a large computational effort. This level of effort has led to the necessity of simplified methods and approximate analysis tools. In this regard, SPO2IDA has emerged as a convenient tool for the assessment of structures. It relates a structure’s backbone characteristics to a set of incremental dynamic analysis (IDA) curves using static pushover analysis (SPO) results and a library of empirical fitting coefficients for the different branches of the idealised SPO backbone. It permits the quantification of structural performance up to structural collapse as a function of seismic intensity in a simple and efficient manner. It has been developed mainly for ductile structures that can be sufficiently represented via a SPO backbone with a certain ductile post-yield hardening followed by a post-peak degradation. This behaviour is quite representative of ductile RC and steel moment-resisting frames and has resulted in the tool being widely adopted. However, the same may not be observed when dealing with reinforced concrete (RC) frames with masonry infill, a structural typology that still requires significant addressing in the earthquake engineering field. The present study describes an extension to this methodology for structural typologies with a more particular backbone behaviour, typical of RC frames with masonry infill panels, since differences in backbone behaviour compared to typical structures render the extension of the original tool inappropriate and at times unconservative. Extensive analyses were conducted to investigate the behaviour and trends when pushing infilled RC frames up to complete structural collapse. A new library of empirical coefficients was then fitted and proposed by considering a large database of representative backbones to result in an extended SPO2IDA proposal for infilled RC frames. It is then shown how these coefficients provide a much-improved matching, when compared to the original tool for this specific case, both in terms of the produced IDA traces and also the drift-based mean annual rates of exceedance.

Psr j0737-3039 : interacting pulsars in x-rays

Abstract: We present the results of a ~230 ks long X-ray observation of the relativistic double-pulsar system PSR J0737–3039 obtained with the XMM-Newton satellite in 2006 October. We confirm the detection in X-rays of pulsed emission from PSR J0737–3039A (PSR A), mostly ascribed to a soft nonthermal power-law component (Γ ~ 3.3) with a 0.2-3 keV luminosity of ~1.9 × 1030 erg s−1 (assuming a distance of 500 pc). For the first time, pulsed X-ray emission from PSR J0737–3039B (PSR B) is also detected in part of the orbit. This emission, consistent with thermal radiation with temperature kBT 30 eV and a bolometric luminosity of ~1032 erg s−1, is likely powered by heating of PSR B's surface caused by PSR A's wind. A hotter (~130 eV) and fainter (~5 × 1029 erg s−1) thermal component, probably originating from backfalling particles heating polar caps of either PSR A or PSR B, is also required by the data. No signs of X-ray emission from a bow shock between PSR A's wind and the interstellar medium or PSR B's magnetosphere are present. The upper limit on the luminosity of such a shock component (~1029 erg s−1) constrains the wind magnetization parameter σM of PSR A to values greater than 1.

Magnetars: a short review and some sparse considerations

Abstract: We currently know about 30 magnetars: seemingly isolated neutron stars whose properties can be (in part) comprehended only acknowledging that they are endowed with magnetic fields of complex morphology and exceptional intensity—at least in some components of the field structure. Although magnetars represent only a small percentage of the known isolated neutron stars, there are almost certainly many more of them, since most magnetars were discovered in transitory phases called outbursts, during which they are particularly noticeable. In outburst, in fact, a magnetar can be brighter in X-rays by orders of magnitude and usually emit powerful bursts of hard-X/soft-gamma-ray photons that can be detected almost everywhere in the Galaxy with all-sky monitors such as those on board the Fermi satellite or the Neil Gehrels Swift Observatory. Magnetars command great attention because the large progress that has been made in their understanding is proving fundamental to fathom the whole population of isolated neutron stars, and because, due to their extreme properties, they are relevant for a vast range of different astrophysical topics, from the study of gamma-ray bursts and superluminous supernovae, to ultraluminous X-ray sources, fast radio bursts, and even to sources of gravitational waves. Several excellent reviews with different focuses were published on magnetars in the last few years: among others, Israel and Dall’Osso, Bursts and flares from highly magnetic pulsars, in Proceedings of the First Session of the Sant Cugat Forum on Astrophysics High-Energy Emission from Pulsars and Their Systems, ed. by D.F. Torres, N. Rea. Astrophysics and Space Science Proceedings (Springer, Heidelberg, 2011), pp. 279–298, Rea and Esposito, Magnetar outbursts: an observational review, in High-Energy Emission from Pulsars and Their Systems. Proceedings of the First Session of the Sant Cugat Forum on Astrophysics, ed. by D.F. Torres, N. Rea. Astrophysics and Space Science Proceedings (Springer, Heidelberg, 2011), pp. 247–273, Turolla and Esposito Int J Mod Phys D 22:1330024-163, 2013, Mereghetti, et al. Space Sci Rev 191:315–338, 2015, Turolla et al., 78:116901, 2015; Kaspi and Beloborodov Annu Rev Astron Astrophys 55:261–301, 2017. Here, we quickly recall the history of these sources and travel through the main observational facts, trying to touch some recent and sometimes little-discussed ramifications of magnetars.

Lockdown Effects on Healthy Cognitive Aging During the COVID-19 Pandemic: A Longitudinal Study

Abstract: The COVID-19 pandemic is a health issue leading older adults to an increased vulnerability to unfavorable outcomes. Indeed, the presence of physical frailty has recently led to higher mortality due to SARS-CoV-2 infection. However, no longitudinal studies have investigated the role of neuropsychogeriatric factors associated with lockdown fatigue in healthy cognitive aging. Eighty-one healthy older adults were evaluated for their neuropsychological characteristics, including physical frailty, before the pandemic (T0). Subsequently, 50 of them agreed to be interviewed and neuropsychologically re-assessed during the lockdown (T1) and immediately after it (T2). Moreover, during another home confinement, they performed a psychological screening (T3) to evaluate possible mood changes and fatigue. According to Fried's frailty criteria, at T0, 63% of the sample was robust, 34.5% pre-frail, and only 2.5% frail. Significantly, these subjects presented a decrease in handgrip strength and walking speed (29.6 and 6.1%, respectively). Results from Principal Component Analyses and multiple regression models highlighted the contribution of "cognitive" and "psychological" factors (i.e., attentive-executive performance and mood deflections) in explaining handgrip strength and gait speed. At T3, lockdown fatigue was explained by higher scores on the Beck Depression Inventory and lower scores on the Trail Making Test part A. Results from a moderated-mediation model showed that the effect of psychomotor speed on lockdown fatigue was mediated by depression, with a moderating effect of gait speed. Our findings highlight the complex interrelationship between cognitive, psychological, and physical factors in the emergence of pandemic fatigue in a carefully selected older population.