543 research outputs found
Anisotropic CR diffusion and gamma-ray production close to supernova remnants, with an application to W28
Cosmic rays that escape their acceleration site interact with the ambient
medium and produce gamma rays as the result of inelastic proton-proton
collisions. The detection of such diffuse emission may reveal the presence of
an accelerator of cosmic rays, and also constrain the cosmic ray diffusion
coefficient in its vicinity. Preliminary results in this direction have been
obtained in the last years from studies of the gamma-ray emission from
molecular clouds located in the vicinity of supernova remnants, which are the
prime candidate for cosmic ray production. Hints have been found for a
significant suppression of the diffusion coefficient with respect to the
average one in the Galaxy. However, most of these studies rely on the
assumption of isotropic diffusion, which may not be very well justified. Here,
we extend this study to the case in which cosmic rays that escape an
accelerator diffuse preferentially along the magnetic field lines. As a first
approximation, we further assume that particles are strongly magnetized and
that their transport perpendicular to the magnetic field is mainly due to the
wandering of the field lines. The resulting spatial distribution of runaway
cosmic rays around the accelerator is, in this case, strongly anisotropic. An
application of the model to the case of the supernova remnant W28 demonstrates
how the estimates of the diffusion coefficient from gamma-ray observations
strongly depend on the assumptions made on the isotropy (or anisotropy) of
diffusion. For higher levels of anisotropy of the diffusion, larger values of
the diffusion coefficient are found to provide a good fit to data. Thus,
detailed models for the propagation of cosmic rays are needed in order to
interpret in a correct way the gamma-ray observations.Comment: 10 pages, 5 figures, submitted to MNRA
Non-linear Cosmic Ray propagation close to the acceleration site
Recent advances on gamma-ray observations from SuperNova Remnants and
Molecular Clouds offer the possibility to study in detail the properties of the
propagation of escaping Cosmic Rays (CR). However, a complete theory for CR
transport outside the acceleration site has not been developed yet. Two
physical processes are thought to be relevant to regulate the transport: the
growth of waves caused by streaming instability, and possible wave damping
mechanisms that reduce the growth of the turbulence. Only a few attempts have
been made so far to incorporate these mechanisms in the theory of CR diffusion.
In this work we present recent advances in this subject. In particular, we show
results obtained by solving the coupled equations for the diffusion of CRs and
the evolution of Alfven waves. We discuss the importance of streaming
instabilities and wave damping in different ISM phases.Comment: Contribution to the Proceedings of the 34th International Cosmic Ray
Conference (ICRC 2015), The Hague, The Netherland
Inspiratory muscle training in difficult to wean patients: work it harder, make it better, do it faster, makes us stronger
Weaning from prolonged mechanical ventilation is a complex, time-consuming process that involves the loss of force/generating capacity of the inspiratory muscle. In their study 'Inspiratory muscle strength training improves the outcome in failure to wean patients: a randomized trial', Martin and colleagues showed that the use of an inspiratory muscle strength program increased the maximal inspiratory pressure and improved weaning success compared to a control group. The study was performed mainly in post-surgical patients, however, and the results, therefore, may not be generalizable to other subsets of patients, such as those with chronic obstructive pulmonary disease or congestive heart failure. Indeed, the study applied so-called 'strength training' and not 'endurance training', which may be more appropriate in certain circumstances
Non-linear diffusion of cosmic rays escaping from supernova remnants - I. The effect of neutrals
Supernova remnants are believed to be the main sources of galactic Cosmic
Rays (CR). Within this framework, particles are accelerated at supernova
remnant shocks and then released in the interstellar medium. The mechanism
through which CRs are released and the way in which they propagate still remain
open issues. The main difficulty is the high non-linearity of the problem: CRs
themselves excite the magnetic turbulence that confines them close to their
sources. We solve numerically the coupled differential equations describing the
evolution in space and time of the escaping particles and of the waves
generated through the CR streaming instability. The warm ionized and warm
neutral phases of the interstellar medium are considered. These phases occupy
the largest fraction of the disc volume, where most supernovae explode, and are
characterised by the significant presence of neutral particles. The friction
between those neutrals and ions results in a very effective wave damping
mechanism. It is found that streaming instability affects the propagation of
CRs even in the presence of ion-neutral friction. The diffusion coefficient can
be suppressed by more than a factor of over a region of few tens of pc
around the remnant. The suppression increases for smaller distances. The
propagation of GeV particles is affected for several tens of
kiloyears after escape, while TeV particles are affected for few
kiloyears. This might have a great impact on the interpretation of gamma-ray
observations of molecular clouds located in the vicinity of supernova remnants.Comment: Revised to match the version published in MNRA
ABC: Archeologia a Bedriacum-Calvatone. Un progetto didattico
Nel 2011, con lâavvio del progetto âABC. Archeologia a Bedriacum-Calvatoneâ, fortemente voluto dal Comune di Calvatone (CR) e dalla prof.ssa Maria Teresa Grassi, nasce lâattivitĂ didattica dellâUniversitĂ degli Studi di Milano collegata allo scavo archeologico di Calvatone. Lâobiettivo Ăš quello di raccontare la storia e gli scavi della piccola cittĂ romana di Bedriacum ai bambini e ai ragazzi delle scuole del territorio al fine di sensibilizzarli circa lâimportanza del patrimonio culturale locale. In nove anni (fino al sopraggiungere della pandemia, che ha inevitabilmente procurato una battuta dâarresto), lâattivitĂ didattica rivolta alle scuole, attraverso le visite guidate e con lâausilio di molteplici strumenti di comunicazione, ha registrato quasi duemilacinquecento presenze.In 2011, with the launch of the project called âABC. Archaeology in Bedriacum-Calvatoneâ, promoted by the Municipality of Calvatone (CR) and by Prof. Maria Teresa Grassi, the educational activity of the University of Milan at the archaeological excavation of Calvatone began. The projectâs goal is the communication of research and excavation activities in the Roman settlement of Bedriacum. Communication activities target a wide audience, including schoolchildren and youth in order to raise awareness on the local cultural heritage. During the first nine years (before the emergence of the COVID-19 pandemic in 2020), by using different communication tools, the educational activities have involved almost two thousand and five hundred children and teenagers
Topics in acute respiratory distress syndrome: the patient needs our tender loving and care
This editorial introduces a four-part series on acute respiratory distress syndrome (ARDS) that will cover a wide range of related topics in reviews written by internationally renowned experts. The first part of this series will be published in this issue of the European Respiratory Review by Guérin [1] on the role of prone positioning. This will be followed by articles on the topics of: 1) the role of imaging in the diagnosis and management of ARDS; 2) the novel ventilatory aspects involved in managing patients with ARDS; and 3) how to manage a patient failing conventional ventilation with extracorporeal support, in particular, extracorporeal membrane oxygenation (ECMO)
Manual Massage Therapy for Patients with COPD: A Scoping Review.
Background and objectives: Manual massage therapy is a therapeutic option for the treatment of several pathological conditions affecting the musculoskeletal system. It has been pointed out that massage might be beneficial for COPD patients thanks to therapeutic effects primarily related to hyperemia, increased both skin temperature and blood flow, and activation of the lymphatic system. The present study reports current evidence on the systemic effects of manual massage in patients with COPD. Materials and Methods: A scoping review was conducted on five major databases. The search went through all databases since their inception until December 2018. Results: Seventy-eight citations were retrieved; after the selection process was completed, seven articles were considered eligible. In patients receiving manual massage, improvements were observed in FEV1, dyspnea perception, and in the 6-minute walking test. Conclusions: To date the use of the manual massage in patients with COPD is not supported by substantial evidence in the literature: indeed, it is proposed as a therapeutic option in association with other interventions such as physical exercise
The influence of the media on COPD patientsâ knowledge regarding cardiopulmonary resuscitation
Stefano Nava1, Carmen Santoro1, Mario Grassi2, Nicholas Hill31Respiratory Unit, Fondazione S Maugeri, I R C C S Istituto Scientifico di Pavia, Pavia, Italy; 2Department of Health Sciences, Section of Medical Statistics and Epidemiology, University of Pavia, Pavia, Italy; 3Pulmonary and Critical Care Division, Tufts University, New England Medical Center, Boston, MA, USABackground: The decision whether or not to undertake cardiopulmonary resuscitation (CPR) is a major ethical challenge. Patient preferences may be influenced by multiple factors, including information given by the media.Objectives: We wanted to assess whether patients’ knowledge about CPR survival and outcomes was related to presentation by the media.Methods: 100 consecutive patients with COPD and chronic respiratory failure (CRF) and 100 patients at their first hospital admission for respiratory problems were enrolled. A questionnaire was administered to the patients seeking to ascertain their exposure to health information from the media, and to obtain their opinions on 1) the probability of survival after CPR, 2) the maximal length of time from collapse to CPR that allows a reasonable chance of survival, and 3) long-term outcomes of CPR survivors.Results: The patients overestimated the success rate of CPR (63% of them estimated a hospital survival >40%), while the estimate of long-term outcome and timing of the procedure were more realistic. Bivariate correlations analysis showed significant correlation between the rate of correct responses and the viewing of educational television programs (p = 0.039), but not medical stories, reading of health-oriented newspapers, use of the internet, age, educational level, and the presence of CRF.Conclusions: In conclusion, we have shown that both COPD and “newly admitted” patients’ estimate of survival after CPR is much higher than reported by the current literature. A correct knowledge of CPR procedures and outcomes is significantly correlated with the exposure to “educational” medical TV programs, but not medical stories, newspapers, or internet sources.Keywords: cardiopulmonary resuscitation, chronic respiratory failure, chronic obstructive pulmonary disease, media, televisio
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