During the last two decades Gamma-Ray Astronomy has emerged as a powerful tool to study cosmic ray physics. In fact, photons are not deviated by galactic or extragalactic magnetic fields so their ...directions bring the information of the production sites and are easier to detect than neutrinos. Thus the search for γ primarily address in the framework of the search of cosmic ray sources and to the investigation of the phenomena in the acceleration sites. This note is not a place for a review of ground-based gamma-ray astronomy. We will introduce the experimental techniques used to detect photons from ground in the overwhelming background of CRs and briefly describe the experiments currently in data taking or under installation.
A shower array exploiting the full coverage approach with a high segmentation of the readout allow to image the front of atmospheric showers with unprecedented resolution and detail. The grid ...distance determines the energy threshold (small energy showers are lost in the gap between detectors) and the quality of the shower sampling. Therefore, this experimental solution is needed to detect showers with a threshold in the 100 GeV range. The full coverage approach has been exploited in the ARGO-YBJ experiment. In this contribution we will summarise the advantages of this technique and discuss possible applications in new wide field of view detectors.
Cosmic rays are the most outstanding example of accelerated particles. They are about 1% of the total mass of the Universe, so that cosmic rays would represent by far the most important energy ...transformation process of the Universe. Despite large progresses in building new detectors and in the analysis techniques, the key questions concerning origin, acceleration and propagation of the radiation are still open. One of the reasons is that there are significant discrepancies among the different results obtained by experiments located at ground probably due to unknown systematic errors affecting the measurements. In this note we will focus on detection of Galactic CRs from ground with EAS arrays. This is not a place for a complete review of CR physics (for which we recommend, for instance 1, 2, 3, 4, 5, 6, 7) but only to provide elements useful to understand the basic techniques used in reconstructing primary particle characteristics (energy, mass and arrival direction) from ground, and to show why indirect measurements are difficult and results still conflicting.
Cosmic rays represent one of the most important energy transformation processes of the universe. They bring information about the surrounding universe, our galaxy, and very probably also the ...extragalactic space, at least at the highest observed energies. More than one century after their discovery, we have no definitive models yet about the origin, acceleration and propagation processes of the radiation. The main reason is that there are still significant discrepancies among the results obtained by different experiments located at ground level, probably due to unknown systematic uncertainties affecting the measurements. In this document, we will focus on the detection of galactic cosmic rays from ground with air shower arrays up to 1018 eV. The aim of this paper is to discuss the conflicting results in the 1015 eV energy range and the perspectives to clarify the origin of the so-called ‘knee’ in the all-particle energy spectrum, crucial to give a solid basis for models up to the end of the cosmic ray spectrum. We will provide elements useful to understand the basic techniques used in reconstructing primary particle characteristics (energy, mass, and arrival direction) from the ground, and to show why indirect measurements are difficult and results are still conflicting.
Contrast-induced nephropathy (CIN) impairs clinical outcome in patients undergoing angiographic procedures. The aim of this study was to investigate whether short-term high-dose atorvastatin load ...decreases the incidence of CIN after percutaneous coronary intervention (PCI). Statin-naive patients with acute coronary syndrome undergoing PCI (n = 241) randomly received atorvastatin (80 mg 12 hours before intervention with another 40-mg preprocedure dose, n = 120) or placebo (n = 121). All patients had long-term atorvastatin treatment thereafter (40 mg/day). Primary end point was incidence of CIN defined as postintervention increase in serum creatinine ≥0.5 mg/dl or >25% from baseline. Five percent of patients in the atorvastatin arm developed CIN versus 13.2% of those in the placebo arm (p = 0.046). In the atorvastatin group, postprocedure serum creatinine was significantly lower (1.06 ± 0.35 vs 1.12 ± 0.27 mg/dl in placebo, p = 0.01), creatinine clearance was decreased (80.1 ± 32.2 vs 72.0 ± 26.6 ml/min, p = 0.034), and C-reactive protein peak levels after intervention were decreased (8.4 ± 10.5 vs 13.1 ± 20.8 mg/l, p = 0.01). Multivariable analysis showed that atorvastatin pretreatment was independently associated with a decreased risk of CIN (odds ratios 0.34, 95% confidence interval 0.12 to 0.97, p = 0.043). Prevention of CIN with atorvastatin was paralleled by a shorter hospital stay (p = 0.007). In conclusion, short-term pretreatment with high-dose atorvastatin load prevents CIN and shortens hospital stay in patients with acute coronary syndrome undergoing PCI; anti-inflammatory effects may be involved in this renal protection. These results lend further support to early use of high-dose statins as adjuvant pharmacologic therapy before percutaneous coronary revascularization.
To date, very few nationwide studies addressing the way in which mental health services are addressing the current pandemics have been published. The present paper reports data obtained from a survey ...relating to the Italian mental health system conducted during the first phase of the Covid-19 epidemic.
Two online questionnaires regarding Community Mental Health Centres (CMHC) and General Hospital Psychiatric Wards (GHPW), respectively, were sent to the Heads of all Italian Mental Health Departments (MHDs). Statistical analysis was carried out by means of Chi Square test with Yates correction or the Fisher Exact test, as needed.
Seventy-one (52.9%) of the 134 MHDs and 107 (32.6%) of the 318 GHPWs returned completed questionnaires. Less than 20% of CMHCs were closed and approx. 25% had introduced restricted access hours. A substantial change in the standard mode of operation in CMHCs was reported with only urgent psychiatric interventions, compulsory treatments and consultations for imprisoned people continuing unchanged. All other activities had been reduced to some extent. Remote contacts with users had been set up in about 75% of cases. Cases of COVID positivity were reported for both staff members (approx. 50% of CHMCs) and service users (52% of CHMCs). 20% of CMHCs reported cases of increased aggressiveness or violence among community patients, although only 8.6% relating to severe cases. Significant problems emerged with regard to the availability of personal protective equipment (PPE) for staff members. A reduced number of GHPWs (- 12%), beds (approx.-30%) and admissions were registered (87% of GHPWs). An increase in compulsory admissions and the rate of violence towards self or others among inpatients was reported by 8% of GHPWs. Patient swabs were carried out in 50% of GHPWs. 60% of GHPWs registered the admission to general COVID-19 Units of symptomatic COVID+ non-severe psychiatric patients whilst COVID+ severe psychiatric patients who were non-collaborative were admitted to specifically set up "COVID-19" GHPWs or to isolated areas of the wards purposely adapted for the scope.
The pandemic has led to a drastic reduction in levels of care, which may produce a severe impact on the mental health of the population in relation to the consequences of the expected economic crisis and of the second ongoing wave of the pandemic.
EAS arrays are survey instruments able to monitor continuously all the overhead sky. Their sensitivity in the sub-TeV/TeV energy domain cannot compete with that of Cherenkov telescopes, but the wide ...field of view (about 2 sr) is ideal to complement directional detectors by performing unbiased sky surveys, by monitoring variable or flaring sources such as Active Galactic Nuclei (AGN) and to discover transients or explosive events (GRBs). Arrays are well suited to study extended sources, such as the Galactic diffuse emission, and to measure the spectra of Galactic sources at the highest energies (near or beyond 100 TeV). An EAS array is able to detect at the same time events induced by photons and charged cosmic rays, thus studying the connection between these two messengers of the non-thermal Universe. Therefore, these detectors are, by definition, multi-messenger instruments. All EAS arrays presently in operation or under installation are located in the Northern hemisphere. The scientific potential of a next-generation survey instrument in the Southern Hemisphere will be presented and briefly discussed.
Platelet reactivity predicts ischemic outcomes in patients who undergo percutaneous coronary intervention (PCI), but the correlation of heightened platelet response with bleeding has not been ...characterized. The aim of this study was to evaluate whether low platelet reactivity by point-of-care measurement after clopidogrel administration correlates with bleeding complications of PCI. A total of 310 patients receiving clopidogrel before PCI were prospectively enrolled. Platelet reactivity was measured with the VerifyNow P2Y12 assay. The primary end point was the 30-day incidence of major bleeding or entry-site complications according to quartile distribution of P2Y12 reaction units (PRU). The primary end point occurred more frequently in patients with preprocedural PRU levels in the lowest quartile compared to those in the highest quartile (10.1% vs 1.3%, p = 0.043), due mainly to entry-site hemorrhages. Absolute PRU levels were lower in patients with major bleeding (171 ± 49 vs 227 ± 68 in patients without, p = 0.002). On multivariate analysis, pre-PCI PRU levels in the first quartile were associated with a 4.5-fold increased risk for major bleeding (odds ratio 4.5, 95% confidence interval 1.9 to 25.9, p = 0.01). By receiver-operating characteristic curve analysis, the optimal cutoff for the primary end point was a pre-PCI PRU value ≤189 (area under the curve 0.76, 95% confidence interval 0.66 to 0.87, p = 0.001). In conclusion, this study suggests that an enhanced response to clopidogrel may be associated with higher risk for early major bleeding or entry-site complications in patients who undergo PCI. Point-of-care monitoring of platelet reactivity after clopidogrel administration may help identify patients in whom individualized strategies are indicated to limit bleeding complications after coronary intervention.
Recent findings in atrial fibrillation (AF) patients receiving oral anticoagulation showed that diabetes without insulin therapy has a thromboembolic risk comparable to nondiabetic patients, whereas ...only diabetic patients on insulin have a heightened thromboembolic risk. We explored possible pathophysiological correlates of such finding on 90 AF patients on oral anticoagulation, divided according to diabetes status (n = 30 without diabetes; n = 29 with diabetes on oral antidiabetic drugs; n = 31 with insulin-requiring diabetes). We assessed von Willebrand Factor (VWF) concentration (VWF:Ag) and activity (VWF R:Co) as measures of endothelial dysfunction; and thrombin-activatable fibrinolysis inhibitor (TAFI) and prothrombin fragment 1 + 2 (F1+2) levels as markers of fibrinolytic activity and thrombin generation. Values of VWF:Ag, VWF:RCo, and TAFI were similar in the 3 groups. Patients with diabetes requiring insulin had significantly higher levels of F1+2 (median 23.1 pg/ml interquartile range 17.6; 33.5) than those without diabetes (16.3 pg/ml 11.5; 22.5, p = 0.036) and diabetic patients on oral antidiabetic drugs (20.6 pg/ml 13.3; 29, p = 0.046). Thus, in AF patients receiving oral anticoagulation, those with diabetes, regardless of the diabetes type (with or without insulin therapy), and those without diabetes have comparable indices of the explored parameters of endothelial dysfunction and fibrinolytic activity. Despite anticoagulant therapy, thrombin generation is selectively higher in diabetic patients' on insulin than in those without diabetes or with diabetes on oral antidiabetic drugs, with no differences between these latter 2 conditions. Thrombin generation might thus be a predominant contributor to the excess of thromboembolic risk in AF patients on insulin-requiring diabetes.
The ARGO-YBJ experiment has been in stable data taking for about 5 years at the YangBaJing Cosmic Ray Observatory (Tibet, P.R. China, 4300 m a.s.l., 606 g/cm2). With a duty-cycle greater than 86% the ...detector collected about 5×1011 events in a wide energy range, from few hundreds GeV up to about 10 PeV. Exploiting the full coverage approach with a high segmentation of the readout at high altitude, ARGO-YBJ imaged the front of Extensive Air Showers (EAS) with unprecedented resolution and detail. A number of important problems in galactic cosmic ray physics has been faced through different analyses. In this contribution we summarize the latest results in gamma-ray astronomy and in cosmic ray physics.
PDF
