2,193 research outputs found

    Entanglement entropy and the determination of an unknown quantum state

    Full text link
    An initial unknown quantum state can be determined with a single measurement apparatus by letting it interact with an auxiliary, "Ancilla", system as proposed by Allahverdyan, Balian and Nieuwenhuizen [Phys. Rev. Lett. 92, 120402 (2004)]. In the case of two qubits, this procedure allows to reconstruct the initial state of the qubit of interest S by measuring three commuting observables and therefore by means of a single apparatus, for the total system S + A at a later time. The determinant of the matrix of the linear transformation connecting the measurements of three commuting observables at time t > 0 to the components of the polarization vector of S at time t = 0 is used as an indicator of the reconstructability of the initial state of the system S. We show that a connection between the entanglement entropy of the total system S + A and such a determinant exists, and that for a pure state a vanishing entanglement individuates, without a need for any measurement, those intervals of time for which the reconstruction procedure is least efficient. This property remains valid for a generic dimension of S. In the case of a mixed state this connection is lost.Comment: 5 pages 2 figures, accepted for publication on Physical Review

    Modeling and steering magneto-elastic micro-swimmers inspired by the motility of sperm cells

    Get PDF
    Controlling artificial devices that mimic the motion of real microorganisms, is attracting increasing interest, both from the mathematical point of view and applications. A model for a magnetically driven slender micro-swimmer, mimicking a sperm cell is presented, supported by two examples showing how to steer it. Using the Resistive Force Theory (RTF) approach [J. Gray and J. Hancock, J. Exp. Biol. 32, 802 (1955)] to describe the hydrodynamic forces, the micro-swimmer can be described by a driftless affine control system where the control is an external magnetic field. Moreover we discuss through at first an asymptotic analysis and then by numerical simulations how to realize different kinds of paths

    Education and training among Italian postgraduate medical schools in public health: a comparative analysis

    Get PDF
    Analisi comparativa dei percorsi formativi offerti dalle Scuole di specializzazione di Igiene e Medicina Preventiva in Italia Background: Il percorso formativo dello specialista in Igiene e Medicina Preventiva dovrebbe garantire adeguate conoscenze tecnico-scientifiche e professionali nei campi della medicina preventiva, della promozione della salute e della programmazione dei servizi sanitari secondo quanto indicato anche dal DM 285/2005. La Consulta degli Specializzandi, da sempre coinvolta in attività di monitoraggio della formazione a livello nazionale, si prefigge l’obiettivo di valutare l’omogeneità delle proposte formative tra le diverse sedi italiane, non solo per segnalare le criticità, ma anche per evidenziarne le opportunità. Metodi: Lo studio, di tipo cross-sectional, è stato condotto mediante la somministrazione di un questionario semi-strutturato inviato per la compilazione ai rappresentanti delle 32 le Scuole di Igiene e Medicina Preventiva italiane. Lo strumento di valutazione è costituito da quattro sezioni: informazioni generali, attività formativa universitaria, attività formativa extra-universitaria, attività formativa intersettoriale. L’indagine è stata svolta nel periodo tra marzo e maggio 2013 ed è stata prodotta un’analisi descrittiva dei dati ottenuti. Risultati: Il questionario è stato compilato da 28 Scuole su 32 (tasso di risposta 88%), distribuite su tutto il territorio nazionale. Il numero di medici in formazione varia tra 7 e 31 e il rapporto tra docenti del settore scientifico-disciplinare di interesse e i discenti è compreso tra 0,2 e 2. Per quanto riguarda la didattica, solo in 4 Scuole si effettuano tutti i corsi previsti dal DM. La maggior parte delle sedi svolge almeno il 75% dei corsi previsti, ma esistono sedi in cui il numero di corsi è inferiore al 50%. La maggior parte delle Scuole svolge più del 60% delle attività professionalizzanti essenziali secondo il decreto, ma 2 Scuole non arrivano al 50%. Tutte le Scuole prevedono un tirocinio di 6-12 mesi in ASL, affiancando principalmente attività del Dipartimento di Prevenzione. Ovunque è previsto un periodo in Direzione Medica Ospedaliera, mentre le Strutture Riabilitative rientrano raramente nella rete formativa. Nella maggioranza delle Scuole è possibile frequentare aziende con rischio biologico oppure seguire simili attività nei Servizi dedicati della ASL. Molte Scuole, infine, consentono di frequentare diverse strutture territoriali (Agenzia di Controllo delle Acque), regionali (Assessorati) o nazionali (Ministero, Istituto Superiore di Sanità); in alcuni casi si tratta di Università gemellate e Istituti di Ricerca. Conclusioni: Nonostante il DM 285/2005 indichi quali siano le fondamenta della sanità pubblica, la flessibilità nella scelta formativa è vista come requisito essenziale per ottimizzare le risorse e contestualizzare l’adeguata formazione del medico in formazione specialistica in Igiene e Medicina Preventiva. La maggior parte delle Scuole di Specializzazione italiane dovrebbe però prevedere lo svolgimento della quasi totalità delle attività formative previste, al fine di non creare disuguaglianze formative tra gli specializzandi. Infine, considerato che la sanità pubblica è una disciplina in continuo divenire, il DM del 2005 andrebbe rivisitato tenendo in considerazione la flessibilità della formazione ed i continui cambiamenti dei bisogni di salute essenziali della popolazione. Inoltre, nel processo di rivisitazione dei bisogni formativi dei medici in formazione specialistica, dovrebbero essere coinvolti anche i discenti al fine di rafforzare il potere e l’efficacia dell’insegnamento.Background The postgraduate medical Schools in Public Health (locally known as School of Hygiene and Preventive Medicine) should ensure adequate scientific and technical knowledge and professional skills in preventive medicine, health promotion and healthcare planning as provided by Ministerial Decree 285/2005. The Italian Committee of Medical Residents in Hygiene, Preventive Medicine and Public Health of the Italian Society of Hygiene, Public Health and Preventive Medicine - S.It.I. (Consulta Nazionale dei medici in formazione specialistica S.It.I.) has always been engaged in monitoring activities on public health teaching, guaranteeing the homogeneity of educational proposals among all national Schools in Public Health. The purpose of this study is to provide a 'snapshot' of public health education and training in Italy and to identify the improvement actions needed for implementing an innovative and homogeneous public health training. Methods: A cross-sectional study was carried out over a period of three months (March to May 2013). A self-administered questionnaire was e-mailed to local Committee’s delegates of all 32 postgraduate medical Schools in Public Health in Italy. The questionnaire was structured in four sections: general information, University education and training, extra-University training, interdisciplinary activities. The majority of local Committee’s delegates have agreed to be enrolled in the survey. Results: A total of 28 questionnaires were returned (88% response rate). The number of residents in each Italian School in Public Health ranged from 7 to 31. The distribution of professors in relation to residents is not similar for each University Schools. The ratio professors/residents spanning from 0.2 to 2. About teaching, only 4 University Schools offered all courses requested by Ministerial Decree 285/2005. Most of them offered at least 75% of the requested courses, but there were Schools in which the courses were less than 50%. The vast majority of schools held more than 60% of the qualifying activities considered essential according to the Decree, while 2 Schools were below 50%. All Schools required an internship of 6-12 months in local health authority offices (ASL), mainly concerning the Department of Prevention activities. In all Schools a period of stay in a Hospital Medical Direction was scheduled, while professional activities at Residential care homes were very rarely included in training programmes. Many Schools allowed residents to attend companies with biological hazard or to follow similar activities in dedicated services of ASL. Finally, in the majority of Schools, a training period in various local (Service for Water Control), regional (Departments) or national (Ministry, National Institute of Health) health facilities was contemplated and, in some cases, also in other Universities or Research Institutes. Conclusions: Although the Ministerial Decree indicates the essential milestones of the public health education, flexibility is seen as an important element in order to optimize resources and contextualize the adequate education of residents. In any case, at least regarding public health courses, the majority of University education and extra-University training activities should be carried out by all Schools. In order to obtain shared knowledge and skills, the Ministerial Decree should be revised taking into account flexibility and changing as intrinsic characteristics of public health profession and learners should be involved in the reform to strengthening the role of public health teachin

    Environmental tobacco smoke: health policy and focus on Italian legislation.

    Get PDF
    Worldwide tobacco smoking kills nearly 6 million people each year, including more than 600,000 non-smokers who die from smoke exposure. Environmental tobacco smoke (ETS, also called secondhand smoke, involuntary smoke, or passive smoke) is the combination of sidestream smoke, the smoke given off by a burning tobacco product and mainstream smoke, the smoke exhaled by smokers. People may be exposed to ETS in homes, cars, workplaces, and public places, such as bars, restaurants, and recreational settings. In addition, there is another type of smoke which until now has not been recognized: the so-called thirdhand smoke, that comes from the reaction of mainstream smoke and environmental nitrous acid (HNO2) making carcinogenic tobacco-specific nitrosamines (TSNAs). The effects of ETS on human health are well-known, passive smoking is harmful to those who breathe the toxins and it is a serious problem for public health. The smoking ban in Italy had reduced ETS pollution, as in the United States and in other countries all over the world. However, the implementation of comprehensive legislation on smoking policy will necessitate other tobacco control measures for its successful fulfillment: increased media awareness, telephone smoking cessation helplines and smoking cessation support services could be an opportunity to ensure awareness, comprehension and support to those who want to quit smoking. The effectiveness of legislative efforts will also depend on successful enforcement of smoking bans and compliance with the legislation. This review summarizes the evidences about the effect of ETS and provides an overview of smoke-free laws and policies

    Dimensionality Reduction, Classification and Reconstruction Problems in Statistical Learning Approaches

    Get PDF
    Statistical learning theory explores ways of estimating functional dependency from a given collection of data. The specific sub-area of supervised statistical learning covers important models like Perceptron, Support Vector Machines (SVM) and Linear Discriminant Analysis (LDA). In this paper we review the theory of such models and compare their separating hypersurfaces for extracting group-differences between samples. Classification and reconstruction are the main goals of this comparison. We show recent advances in this topic of research illustrating their application on face and medical image databases.Statistical learning theory explores ways of estimating functional dependency from a given collection of data. The specific sub-area of supervised statistical learning covers important models like Perceptron, Support Vector Machines (SVM) and Linear Discriminant Analysis (LDA). In this paper we review the theory of such models and compare their separating hypersurfaces for extracting group-differences between samples. Classification and reconstruction are the main goals of this comparison. We show recent advances in this topic of research illustrating their application on face and medical image databases

    The Sexual Long COVID (SLC): Erectile Dysfunction as a Biomarker of Systemic Complications for COVID-19 Long Haulers

    Get PDF
    Introduction: Long term complications of COVID-19, the disease caused by the SARS-CoV-2, involve many organ systems, dramatically worsening the quality of life, and finally contributing to impaired physical functioning. Despite the presence of well-identified pathogenetic mechanisms, the effect of "Long COVID" on sexual health has been only marginally addressed. Objectives: To provide coverage of the current literature on long COVID, its epidemiology, pathophysiology, and relevance for erectile function. Methods: Comprehensive review of literature pertaining to the epidemiology and pathophysiology of long COVID, and its relevance for erectile function. Results: Symptoms of long COVID are highly prevalent and involve almost all systems of the human body, with a plethora of clinical manifestations which range from minor nuisances to life-threatening conditions. "Brain fog" and fatigue are the most common complaints, although other neuropsychiatric complications, including sensory dysfunctions, anxiety, depression, and cerebrovascular events have also been reported. The respiratory and cardiovascular systems are also affected, with dyspnea, pulmonary fibrosis, endothelial dysfunction, and myocarditis occurring in some COVID long haulers. A subset of patients might develop endocrine manifestations, including onset of diabetes, thyroid dysfunction, and hypogonadism. Overall, long COVID features many complications which can impair erectile function by multiple pathogenetic mechanisms, and which could require tailored treatment: (i) careful investigation and management from the sexual medicine expert are therefore much needed, (ii) and future research on this topic is warranted. Conclusion: in COVID-19 long haulers, several complications can adversely affect erectile function which, upon future tailored studies, could be used as biomarker for the severity of the long COVID disease and for its follow-up. Sansone A, Mollaioli D, Limoncin E et al. The Sexual Long COVID (SLC): Erectile Dysfunction as a Biomarker of Systemic Complications for COVID-19 Long Haulers. Sex Med Rev 2021;XX:XXX-XXX
    • …
    corecore