74 research outputs found
The Rapidly Flaring Afterglow of the Very Bright and Energetic GRB 070125
We report on multi-wavelength observations, ranging from the X-ray to radio
wave bands, of the IPN-localized gamma-ray burst GRB 070125. Spectroscopic
observations reveal the presence of absorption lines due to O I, Si II, and C
IV, implying a likely redshift of z = 1.547. The well-sampled light curves, in
particular from 0.5 to 4 days after the burst, suggest a jet break at 3.7 days,
corresponding to a jet opening angle of ~7.0 degrees, and implying an intrinsic
GRB energy in the 1 - 10,000 keV band of around E = (6.3 - 6.9)x 10^(51) erg
(based on the fluences measured by the gamma-ray detectors of the IPN network).
GRB 070125 is among the brightest afterglows observed to date. The spectral
energy distribution implies a host extinction of Av < 0.9 mag. Two
rebrightening episodes are observed, one with excellent time coverage, showing
an increase in flux of 56% in ~8000 seconds. The evolution of the afterglow
light curve is achromatic at all times. Late-time observations of the afterglow
do not show evidence for emission from an underlying host galaxy or supernova.
Any host galaxy would be subluminous, consistent with current GRB host-galaxy
samples. Evidence for strong Mg II absorption features is not found, which is
perhaps surprising in view of the relatively high redshift of this burst and
the high likelihood for such features along GRB-selected lines of sight.Comment: 50 pages, 9 figures, 5 tables Accepted to the Astrophysical Journa
The characteristics and activities of child and adolescent mental health services in Italy: a regional survey
<p>Abstract</p> <p>Background</p> <p>To date, no studies have assessed in detail the characteristics, organisation, and functioning of Child and Adolescent Mental Health Services (CAMHS). This information gap represents a major limitation for researchers and clinicians because most mental disorders have their onset in childhood or adolescence, and effective interventions can therefore represent a major factor in avoiding chronicity. Interventions and mental health care are delivered by and through services, and not by individual, private clinicians, and drawbacks or limitations of services generally translate in inappropriateness and ineffectiveness of treatments and interventions: therefore information about services is essential to improve the quality of care and ultimately the course and outcome of mental disorders in childhood and adolescence.</p> <p>The present paper reports the results of the first study aimed at providing detailed, updated and comprehensive data on CAMHS of a densely populated Italian region (over 4 million inhabitants) with a target population of 633,725 subjects aged 0-17 years.</p> <p>Methods</p> <p>Unit Chiefs of all the CAMHS filled in a structured 'Facility Form', with activity data referring to 2008 (data for inpatient facilities referred to 2009), which were then analysed in detail.</p> <p>Results</p> <p>Eleven CAMHS were operative, including 110 outpatient units, with a ratio of approximately 20 child psychiatrists and 23 psychologists per 100,000 inhabitants aged 0-17 years. All outpatient units were well equipped and organized and all granted free service access. In 2008, approximately 6% of the target population was in contact with outpatient CAMHS, showing substantial homogeneity across the eleven areas thereby. Most patients in contact in 2008 received a language disorder- or learning disability diagnosis (41%). First-ever contacts accounted for 30% of annual visits across all units. Hospital bed availability was 5 per 100,000 inhabitants aged 0-17 years.</p> <p>Conclusion</p> <p>The percentage of young people in contact with CAMHS for mental disorders is in line with those observed in previous epidemiological studies. The overall number of child psychiatrists per 100,000 inhabitants is one of the highest in Europe and it is comparable with the most well equipped areas in the US. This comparison should be interpreted with caution, however, because in Italy, child psychiatrists also treat neurological disorders. Critical areas requiring improvement are: the uneven utilisation of standardised assessment procedures and the limited availability of dedicated emergency services during non-office hours (e.g., nights and holidays).</p
Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study
Summary
Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally.
Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies
have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of
the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income
countries globally, and identified factors associated with mortality.
Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to
hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis,
exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a
minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical
status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary
intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause,
in-hospital mortality for all conditions combined and each condition individually, stratified by country income status.
We did a complete case analysis.
Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital
diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal
malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome
countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male.
Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3).
Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income
countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups).
Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome
countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries;
p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients
combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11],
p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20
[1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention
(ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety
checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed
(ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of
parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65
[0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality.
Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome,
middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will
be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger
than 5 years by 2030
Accidental Continuous Releases from Coal Processing in Semi-Confined Environment
Notwithstanding the enforcement of ATEX EU Directives (94/9/EC of 23 March 1994) and safety management system application, explosions in the coal sector still claim lives and cause huge economic losses. Even a consolidated activity like coke dry distillation allows the opportunity of preventing explosion risk connected to fugitive emissions of coke oven gas. Considering accidental releases under semi-confined conditions, a simplified mathematical approach to the maximum allowed gaseous build-up is developed on the basis of the intrinsic hazards of the released compound. The results will help identifying and assessing low rate release consequences therefore to set-up appropriate prevention and control measures. The developed methodology was tested at the real-scale and validated by numerical computational fluid dynamics (CFD) simulations showing the effectiveness of the methodology to evaluate and mitigate the risk connected to confined hazardous releases
A theoretical approach to risk evaluation in connection with oxygen releases
Oxygen\u2013enriched combustion offers several advantages, including higher combustion efficiency and higher CO2 concentration in the flue gas, allowing an easier and cheaper CO2 separation from the gas itself. In addition, oxygen combustion is considered in the IPCC list as a category
of CCS options for large point source emitters. Oxygen enriched process can be adopted to enhance sulphur recovery in the effluent stream adopting modified Claus processes in refineries. According to international historical data, accidents involving gas pipelines still happen and often result in severe consequences. This implies that measures need to be adopted in order to adequately quantify and thereby to mitigate the risks. In relative terms, the problem of HazMat pipeline risk assessment does not come with hazard analysis, or the estimation of failure frequency, but with the calculation of the consequences. In this paper, we consider the peculiar case of oxygen instantaneous or continuous releases from a pipeline and consequent evolving scenarios. A novel modelling approach to risk evaluation is elaborated starting from the rather common situation of a pipe-way where several gas/liquid lines are localized, in a rather congested industrial area. As an applicative case-study, it is considered a downstream oil industry where
the possibility of replacing the air feeding to Claus plant with oxygen enriched line is investigated, with the aim of enhancing sulphur recovery yield. This technical option from one side can be seen as an approach to process intensification, from the other side poses obvious safety issues
Safety and environmental impact reduction. a case-study applied to coal dry distillation industry
As reported by Trevor Kletz, changes made to improve the environment have sometimes produced unforeseen and hazardous side-effects. Before changing designs, or methods of operation we should try to foresee their effects and we should balance the risks to people against the risks to environment. Notwithstanding technological development, enforcement of ATEX Directives and safety management system application, explosions in the process sector still claim lives and severe economic losses. Experience shows that in the process industry high severity events frequently occur in auxiliary areas, such as transport and storage of raw materials and products. Even a consolidated process like coke dry distillation allows the opportunity of preventing environmental impact, reducing as well explosion risk connected to fugitive emissions. In this activity, two intervention lines were identified: the former deals with accident risk, i.e. the occurrence of hazardous factors that may cause the ignition of coke oven gas during work activities on pressurized gas pipelines. The latter concerns environmental risk reduction referred to the transport of raw material from the harbour temporary storage site to the final plant. Considering explosion risk in confined environment and possible evolving scenarios, a short-cut mathematical approach to the maximum allowed hazardous substance build-up is developed based on the intrinsic hazards of the released material. This framework from one side will help identifying and assessing small hazardous releases consequences in closed areas and set-up appropriate control measures. From the other side, it is adopted in connection with the design of an underground conveyor belt for coal, so as to limit fugitive emissions. In this context, the study involves an in-depth quantitative risk assessment and the planning of severe control and prevention measures suitable to mitigate explosion/fire risk, both reducing the probability and the severity of adverse consequences. The methodology successfully tested at the real-scale can be applied to more complex situations, allowing, as well, the attainment of a more generalized approach for the design, once given the release parameters, the building and plant layout
A study on road tunnel fires using hazmat, with emphasis on critical ventilation velocity
One of the main protective measures to be adopted in case of fires in road/rail tunnels is represented by suitable longitudinal ventilation systems being able to avoid fire and smoke exposure of humans, and to create a safe route upstream for evacuation. The key design parameter is the so-called critical ventilation velocity, i.e. the minimum speed of the longitudinal ventilation avoiding the spread of the smoke produced by fire in the upstream direction, known as \u2018backlayering\u2019. In several studies, the critical velocity was correlated to the fire heat release rate on the basis of semi-empirical models, already adopted in describing nonconfined fires. However, experimental runs both on a laboratory scale and on a real scale, evidenced that such correlations are valid only in connection with fires of limited extent, while at high rates of heat release and when the flame height reaches the tunnel ceiling, the critical velocity can tend asymptotically to a maximum value vca. In this study, reference was made to the worst scenario of hydrocarbon pool fire extended to the whole tunnel section. The main hypotheses the model is based upon are uniform distribution of chemico-physical properties of fire and smoke along the considered transverse section of the tunnel. The evaluation of the critical velocity is performed by solving mass, momentum and energy balances obtained considering possible dynamic interactions among the different fluxes (backlayering, air, flame/smoke column). In particular, the inertial action exerted by fresh air on backlayering was determined on the basis of the experimental results. The asymptotic value of the critical velocity resulting by mathematical modelling is in good agreement with those proposed by other authors, for example by means of complex CFD (computational fluid dynamics) studies. Moreover, the developed model is easily adaptable to the evaluation of vca, when dealing with geometrical conditions different from the ones studied here e.g., tunnel of different geometry, fire not extended to the whole section of the tunnel, obstacle presence in the tunnel, sloping tunnels
A critical approach to safety equipment and emergency time evaluation based on actual information from the Bhopal gas tragedy
As amply reported, after Bhopal disaster process safety got a boost worldwide and risk analysis got applied more generally. Even if the concept of inherent safety, strongly promoted by Trevor Kletz, represents one of the main lessons from this tragedy, in the first part of the paper we focus on Bhopal mitigation measures representing the ultimate relevant layer of protection. Starting from a technical analysis of the whole safety equipment of the plant and relevant empirical evidences, we face the short-cut design of critical safety devices suitable to mitigate release effects. The applied method allows a preliminary design and management tool to evaluate the effectiveness of safety systems and the impact on surroundings. In the second part, we develop an empirical-based framework allowing to identify emergency actions and intervention time and demonstrate how the implementation of these safety measures when reaching a critical pressure of 10 psig in Tank 610, even under the condition of protective equipment out of commission, would have surely mitigated such a high profile tragedy. The paper illustrates the determining contribution to this tragedy of such deficiencies in the safety procedures for handling abnormal situations and emergencies by the company
n-Compartment mathematical model for transient evaluation of fluid curtains in mitigating chlorine releases
A simple n-compartment mathematical model is developed to study the effectiveness of fluid curtains and transient behaviour in mitigating the effects of an accidental chlorine release. The model is obtained considering chemical and physical absorption effectiveness of the toxic cloud by a reacting liquid curtain. The characteristics of the curtain and the evolution were deeply studied by means of replicated wind tunnel experimental runs, according to different operating parameters. An analytical solution of the model is presented. A fairly good agreement was verified between the model predictions and the original experimental results here presented
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