227 research outputs found
Tracing day-zero and forecasting the COVID-19 outbreak in Lombardy, Italy: A compartmental modelling and numerical optimization approach
Introduction Italy became the second epicenter of the novel coronavirus disease 2019 (COVID-19) pandemic after China, surpassing by far Chinaâs death toll. The disease swept through Lombardy, which remained in lockdown for about two months, starting from the 8th of March. As of that day, the isolation measures taken in Lombardy were extended to the entire country. Here, assuming that effectively there was one case âzeroâ that introduced the virus to the region, we provide estimates for: (a) the day-zero of the outbreak in Lombardy, Italy; (b) the actual number of asymptomatic infected cases in the total population until March 8; (c) the basic (R0)and the effective reproduction number (Re) based on the estimation of the actual number of infected cases. To demonstrate the efficiency of the model and approach, we also provide a tentative forecast two months ahead of time, i.e. until May 4, the date on which relaxation of the measures commenced, on the basis of the COVID-19 Community Mobility Reports released by Google on March 29. Methods To deal with the uncertainty in the number of the actual asymptomatic infected cases in the total population Volpert et al. (2020), we address a modified compartmental Susceptible/ Exposed/ Infectious Asymptomatic/ Infected Symptomatic/ Recovered/ Dead (SEIIRD) model with two compartments of infectious persons: one modelling the cases in the population that are asymptomatic or experience very mild symptoms and another modelling the infected cases with mild to severe symptoms. The parameters of the model corresponding to the recovery period, the time from the onset of symptoms to death and the time from exposure to the time that an individual starts to be infectious, have been set as reported from clinical studies on COVID-19. For the estimation of the day-zero of the outbreak in Lombardy, as well as of the âeffectiveâ per-day transmission rate for which no clinical data are available, we have used the proposed SEIIRD simulator to fit the numbers of new daily cases from February 21 to the 8th of March. This was accomplished by solving a mixed-integer optimization problem. Based on the computed parameters, we also provide an estimation of the basic reproduction number R0 and the evolution of the effective reproduction number Re. To examine the efficiency of the model and approach, we ran the simulator to âforecastâ the epidemic two months ahead of time, i.e. from March 8 to May 4. For this purpose, we considered the reduction in mobility in Lombardy as released on March 29 by Google COVID-19 Community Mobility Reports, and the effects of social distancing and of the very strict measures taken by the government on March 20 and March 21, 2020. Results Based on the proposed methodological procedure, we estimated that the expected day-zero was January 14 (min-max rage: January 5 to January 23, interquartile range: January 11 to January 18). The actual cumulative number of asymptomatic infected cases in the total population in Lombardy on March 8 was of the order of 15 times the confirmed cumulative number of infected cases, while the expected value of the basic reproduction number R0 was found to be 4.53 (min-max range: 4.40- 4.65). On May 4, the date on which relaxation of the measures commenced the effective reproduction number was found to be 0.987 (interquartiles: 0.857, 1.133). The model approximated adequately two months ahead of time the evolution of reported cases of infected until May 4, the day on which the phase I of the relaxation of measures was implemented over all of Italy. Furthermore the model predicted that until May 4, around 20% of the population in Lombardy has recovered (interquartile range: *10% to *30%)
The Neuropsychological Profile of Attention Deficits of Patients with Obstructive Sleep Apnea: An Update on the Daytime Attentional Impairment
none7noAbstract: Introduction: Patients with obstructive sleep apnea (OSA) suffer from several neurocognitive
disturbances. One of the neuropsychological processes most investigated in OSA patients is attention,
but the results have been controversial. Here, we update the attention profile of OSA patients with
the final aim to improve attention assessment, with a possible impact on clinical and medical-legal
practices, in terms of which attention subdomains and parameters need consideration and which one
is a high-risk OSA phenotype for attention dysfunctions. Method: For this purpose, we assessed
32 previously untreated OSA patients (26 men and 6 women) under 65 years of age (mean age
53.2 ± 7.3; mean education level 10.4 ± 3.4 years) suffering from moderate to severe sleep apnea and
hypopnea (mean apnea-hypopnea index (AHI) 45.3 ± 22.9, range 16.1â69.6). A control group of
34 healthy participants matched with OSA patients for age, education level, and general cognitive
functioning were also enrolled. The OSA patients and healthy participants were tested through an
extensive computerized battery (Test of Attentional Performance, TAP) that evaluated intensive (i.e.,
alertness and vigilance) and selective (i.e., divided and selective) dimensions of attention and returned
different outcome parameters (i.e., reaction time, stability of performance, and various types of
errors). Data analysis: The data were analyzed by ANCOVA which compared the speed and accuracy
performance of the OSA and control participants (cognitive reserve was treated as a covariate).
The possible mechanisms underlying attention deficits in OSA patients were examined through
correlation analysis among AHI, oxygenation parameters, sleepiness scores, and TAP outcomes and by
comparing the following three phenotypes of patients: severe OSA and severe nocturnal desaturators
(AHI++D+), severe OSA nondesaturators (AHI++Dâ), and moderate OSA nondesaturators (AHI+Dâ).
Results: The results suggest that the OSA patients manifest deficits in both intensive and selective
attention processes and that reaction time (RT) alone is ineffective for detecting and characterizing
their problems, for which error analysis and stability of performance also have to be considered.
Patients with severe OSA and severe hypoxemia underperformed on alertness and vigilance attention
subtests. Conclusions: The data suggest the importance of evaluating attention deficits among OSA
patients through several parameters (including performance instability). Moreover, the data suggest
a multifaceted mechanism underlying attention dysfunction in OSA patients.openAngelelli P., Macchitella L., Toraldo D.M., Abbate E., Marinelli C.V., Ariglian M., De Benedetto M.Angelelli, P.; Macchitella, L.; Toraldo, D. M.; Abbate, E.; Marinelli, C. V.; Ariglian, M.; De Benedetto, M
Exotic radiation from a photonic crystal excited by an ultra-relativistic electron beam
We report the observation of an exotic radiation (unconventional
Smith-Purcell radiation) from a one-dimensional photonic crystal. The physical
origin of the exotic radiation is direct excitation of the photonic bands by an
ultra-relativistic electron beam. The spectrum of the exotic radiation follows
photonic bands of a certain parity, in striking contrast to the conventional
Smith-Purcell radiation, which shows solely a linear dispersion. Key
ingredients for the observation are the facts that the electron beam is in an
ultra-relativistic region and that the photonic crystal is finite. The origin
of the radiation was identified by comparison of experimental and theoretical
results.Comment: 4 pages, 5 figure
Shannon dimensionality of quantum channels and its application to photon entanglement
We introduce the concept of Shannon dimensionality D as a new way to quantify
bipartite entanglement as measured in an experiment. This is applied to
orbital-angular-momentum entanglement of two photons, using two state analyzers
composed of a rotatable angular-sector phase plate that is lens-coupled to a
single-mode fiber. We can deduce the value of D directly from the observed
two-photon coincidence fringe. In our experiment, D varies between 2 and 6,
depending on the experimental conditions. We predict how the Shannon
dimensionality evolves when the number of angular sectors imprinted in the
phase plate is increased and anticipate that D = 50 is experimentally within
reach.Comment: 4 pages, 3 figures, accepted for Physical Review Letter
Obstructive sleep apnea syndrome in the pediatric age: The role of the pneumologist
OBJECTIVE: This review paper aims to summarize the current state of knowledge on the role of the pneumologist in the diagnosis and respiratory treatment of children affected by obstructive Sleep Disordered Breathing (SDB). MATERIALS AND METHODS: A literature review has been performed on the following topics: obstructive SDB and its clinical entities, indications for respiratory treatment of pediatric SDB, and Continuous Positive Airway Pressure (CPAP) and Noninvasive Positive Pressure Ventilation (NIPPV) treatment approach to obstructive SDB. RESULTS: OSDB is related to obesity, craniofacial pathologies, neuromuscular disorders and, most commonly, adenotonsillar hypertrophy. Adenotonsillectomy is the first-choice treatment in children with obstructive apnea secondary to adenotonsillar hypertrophy. CPAP and NIPPV are recommended in cases where Obstructive Sleep Apnea (OSA) persists after surgery or when surgery is contraindicated. Treatment interventions are usually implemented gradually by separately addressing each abnormality that would predispose to obstructive SDB, then reevaluating after each intervention to detect any residual disease and to assess the need for additional treatment. CONCLUSIONS: Many pediatric patients continue to experience problems and symptoms such as hypersomnia and apnea after adenotonsillectomy and need CPAP/NIPPV treatment. Current knowledge is still incomplete, especially with regard to the mechanisms of pathogenesis of pediatric OSA, the factors affecting pediatric OSA, and the phenotypic variability of the disease. A better understanding of these aspects would contribute to the development of new therapies
Perceived Hospital Preparedness Is Negatively Associated With Pandemic-Induced Psychological Vulnerability in Primary Care Employees: A Multicentre Cross-Sectional Observational Study.
The COVID-19 pandemic had a profound negative impact on the psychological wellbeing of healthcare providers (HPs), but little is known about the factors that positively predict mental health of primary care staff during these dire situations.
We conducted an online questionnaire survey among 702 emergency department workers across 10 hospitals in Switzerland and Belgium following the first COVID-19 wave in 2020, to explore their psychological vulnerability, perceived concerns, self-reported impact and level of pandemic workplace preparedness. Participants included physicians, nurses, psychologists and nondirect care employees (administrative staff). We tested for predictors of psychological vulnerability through both an exploratory cross-correlation with rigorous correction for multiple comparisons and model-based path modelling.
Findings showed that the self-reported impact of COVID-19 at work, concerns about contracting COVID-19 at work, and a lack of personal protective equipment were strong positive predictors of Depression, Anxiety, and Stress, and low Resilience. Instead, knowledge of the degree of preparedness of the hospital/department, especially in the presence of a predetermined contingency plan for an epidemic and training sessions about protective measures, showed the opposite effect, and were associated with lower psychological vulnerability. All effects were confirmed after accounting for confounding factors related to gender, age, geographical location and the role played by HPs in the hospital/department.
Difficult working conditions during the pandemic had a major impact on the psychological wellbeing of emergency department HPs, but this effect might have been lessened if they had been informed about adequate measures for minimizing the risk of exposure
Temporary Acceleration of Electrons While Inside an Intense Electromagnetic Pulse
A free electron can temporarily gain a very significant amount of energy if
it is overrun by an intense electromagnetic wave. In principle, this process
would permit large enhancements in the center-of-mass energy of
electron-electron, electron-positron and electron-photon interactions if these
take place in the presence of an intense laser beam. Practical considerations
severely limit the utility of this concept for contemporary lasers incident on
relativistic electrons. A more accessible laboratory phenomenon is
electron-positron production via an intense laser beam incident on a gas.
Intense electromagnetic pulses of astrophysical origin can lead to very
energetic photons via bremsstrahlung of temporarily accelerated electrons
'From mosh pit to posh pit': Festival imagery in the context of the boutique festival
This paper addresses market-based cultural production in the context of the UK festival field, with a focus on the framing of the festival experience through anticipation. In particular, boutique festivals are discussed as examples of a contemporary cultural ?product category? which has emerged and proliferated in the last decade. Through discourse analysis of media representations of boutique festivals, we situate the boutique festival in a broader sociocultural discourse of agency and choice, which makes it meaningful and desirable, and outline the type of consumer it is meant to attract. For the contemporary consumer, the boutique festival is presented as an anticipated experience based on countercultural festival imagery, while simultaneously framing cultural participation through consumption. The paper contributes to a wider debate on the construction of the consumer in the cultural economy
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