132 research outputs found
The mortality of the Italian population: Smoothing techniques on the Lee--Carter model
Several approaches have been developed for forecasting mortality using the
stochastic model. In particular, the Lee-Carter model has become widely used
and there have been various extensions and modifications proposed to attain a
broader interpretation and to capture the main features of the dynamics of the
mortality intensity. Hyndman-Ullah show a particular version of the Lee-Carter
methodology, the so-called Functional Demographic Model, which is one of the
most accurate approaches as regards some mortality data, particularly for
longer forecast horizons where the benefit of a damped trend forecast is
greater. The paper objective is properly to single out the most suitable model
between the basic Lee-Carter and the Functional Demographic Model to the
Italian mortality data. A comparative assessment is made and the empirical
results are presented using a range of graphical analyses.Comment: Published in at http://dx.doi.org/10.1214/10-AOAS394 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Profit participation annuities: a business profitability analysis within a demographic risk sensitive approach
The aim of the paper is to analyze the performance of a portfolio of participating life annuities, focusing on the
minimum acceptable income level throughout the quantiles of the return distribution. The model, in addition to the
necessary consideration of the volatility of financial markets, gives a central role to the impact of the longevity
phenomenon. The sensitivity of the portfolio performance to the survival projection, the presence of a break-even point
and the time of optimum performance are pointed out, under different hypotheses for the participating quota and with
stochastic assumption for the accumulation and the discounting financial processes and for the survival description
Fair value and demographic aspects of the insured loans
The paper deals with the liability valuation of the insured loan in compliance of the fair value requirements for the
financial assets and liabilities, as mapped out by the international boards engaged in this tool. Initially we propose a
closed form for the fair valuation of the mathematical provision in a framework in which the randomness in the mortality
is considered along with the financial risk component. Furthermore, the aim of the paper is to analyze the relevance
of the risk arising from the demographic movements on the insured loan reserve.
The approach we follow implies the mathematical provision calculated as current values, this meaning at current interest
rates and at current mortality rates. In these two variables the basic risk drivers of a life insurance business dwell
and the many-sided risk system consists, in its systematic aspects, in the choice of the adequate models for forecasting
the future scenarios. The relevance of the impact of the risk connected to the choice of the mortality table (table risk)
on the fair value of the mathematical provision is pointed out and quantified using a measurement tool obtained by
conditional expectation calculus. The risk mapping is performed analyzing the accidental risk impact on the insured
loan portfolio liabilities. In all likelihood, insured loan portfolios are not large enough to be considered well diversified
to the aim of the pooling risk reduction; this consideration makes interesting the measuring of the liability variability
caused by the random events connected to mortality (mortality risk). Practical implications of assuming different mortality
scenarios on the reserve fair value are presented, a graphic description of the model risk deriving from the choice
of the demographic model is provided and numerical evidences of the accidental mortality risk are show
Social threat exposure in juvenile mice promotes cocaine-seeking by altering blood clotting and brain vasculature
Childhood maltreatment is associated with increased severity of substance use disorder and frequent relapse to drug
use following abstinence. However, the molecular and neurobiological substrates that are engaged during early traumatic
events and mediate the greater risk of relapse are poorly understood and knowledge of risk factors is to date extremely
limited. In this study, we modeled childhood maltreatment by exposing juvenile mice to a threatening social
experience (social stressed, S-S). We showed that S-S experience influenced the propensity to reinstate cocaineseeking
after periods of withdrawal in adulthood. By exploring global gene expression in blood leukocytes we found that
this behavioral phenotype was associated with greater blood coagulation. In parallel, impairments in brain
microvasculature were observed in S-S mice. Furthermore, treatment with an anticoagulant agent during withdrawal
abolished the susceptibility to reinstate cocaine-seeking in S-S mice. These findings provide novel insights into a
possible molecular mechanism by which childhood maltreatment heightens the risk for relapse in cocaine-dependent
individuals
Multiple mortality modeling in Poisson Lee-Carter framework
The academic literature in longevity field has recently focused on models for detecting multiple population trends (D'Amato et al., 2012b; Njenga and Sherris, 2011; Russolillo et al., 2011, etc.). In particular, increasing interest has been shown about "related" population dynamics or "parent" populations characterized by similar socioeconomic conditions and eventually also by geographical proximity. These studies suggest dependence across multiple populations and common long-run relationships between countries (for instance, see Lazar et al., 2009). In order to investigate cross-country longevity common trends, we adopt a multiple population approach. The algorithm we propose retains the parametric structure of the Lee-Carter model, extending the basic framework to include some cross-dependence in the error term. As far as time dependence is concerned, we allow for all idiosyncratic components (both in the common stochastic trend and in the error term) to follow a linear process, thus considering a highly flexible specification for the serial dependence structure of our data. We also relax the assumption of normality, which is typical of early studies on mortality (Lee and Carter, 1992) and on factor models (see e.g., the textbook by Anderson, 1984). The empirical results show that the multiple Lee-Carter approach works well in the presence of dependence
Radical-containing ultrafine particulate matter initiates epithelial-to-mesenchymal transitions in airway epithelial cells
Environmentally persistent free radicals (EPFRs) in combustion generated particulate matter (PM) are capable of inducing pulmonary pathologies and contributing to the development of environmental asthma. In vivo exposure of infant rats to EPFRs demonstrates their ability to induce airway hyperresponsiveness to methacholine, a hallmark of asthma. However, the mechanisms by which combustion-derived EPFRs elicit in vivo responses remain elusive. In this study, we used a chemically defined EPFR consisting of approximately 0.2 Όm amorphrous silica containing 3% cupric oxide with the organic pollutant 1,2-dichlorobenzene (DCB-230). DCB-230 possesses similar radical content to urban-collected EPFRs but offers several advantages, including lack of contaminants and chemical uniformity. DCB-230 was readily taken up by BEAS-2B and at high doses (200 Όg/cm2) caused substantial necrosis. At low doses (20 Όg/cm2), DCB-230 particles caused lysosomal membrane permeabilization, oxidative stress, and lipid peroxidation within 24 hours of exposure. During this period, BEAS-2B underwent epithelial-to-mesenchymal transition (EMT), including loss of epithelial cell morphology, decreased E-cadherin expression, and increased α-smooth muscle actin (α-SMA) and collagen I production. Similar results were observed in neonatal air-liquid interface culture (i.e., disruption of epithelial integrity and EMT). Acute exposure of infant mice to DCB-230 resulted in EMT, as confirmed by lineage tracing studies and evidenced by coexpression of epithelial E-cadherin and mesenchymal α-SMA proteins in airway cells and increased SNAI1 expression in the lungs. EMT in neonatal mouse lungs after EPFR exposure may provide an explanation for epidemiological evidence supporting PM exposure and increased risk of asthma. Copyright © 2013 by the American Thoracic Society
Predicting needlestick and sharps injuries in nursing students: Development of the SNNIP scale
© 2020 The Authors. Nursing Open published by John Wiley & Sons Ltd. Aim: To develop an instrument to investigate knowledge and predictive factors of needlestick and sharps injuries (NSIs) in nursing students during clinical placements. Design: Instrument development and cross-sectional study for psychometric testing. Methods: A self-administered instrument including demographic data, injury epidemiology and predictive factors of NSIs was developed between October 2018âJanuary 2019. Content validity was assessed by a panel of experts. The instrument's factor structure and discriminant validity were explored using principal components analysis. The STROBE guidelines were followed. Results: Evidence of content validity was found (S-CVI 0.75; I-CVI 0.50â1.00). A three-factor structure was shown by exploratory factor analysis. Of the 238 participants, 39% had been injured at least once, of which 67.3% in the second year. Higher perceptions of âpersonal exposureâ (4.06, SD 3.78) were reported by third-year students. Higher scores for âperceived benefitsâ of preventive behaviours (13.6, SD 1.46) were reported by second-year students
Post-intervention Status in Patients With Refractory Myasthenia Gravis Treated With Eculizumab During REGAIN and Its Open-Label Extension
OBJECTIVE: To evaluate whether eculizumab helps patients with anti-acetylcholine receptor-positive (AChR+) refractory generalized myasthenia gravis (gMG) achieve the Myasthenia Gravis Foundation of America (MGFA) post-intervention status of minimal manifestations (MM), we assessed patients' status throughout REGAIN (Safety and Efficacy of Eculizumab in AChR+ Refractory Generalized Myasthenia Gravis) and its open-label extension. METHODS: Patients who completed the REGAIN randomized controlled trial and continued into the open-label extension were included in this tertiary endpoint analysis. Patients were assessed for the MGFA post-intervention status of improved, unchanged, worse, MM, and pharmacologic remission at defined time points during REGAIN and through week 130 of the open-label study. RESULTS: A total of 117 patients completed REGAIN and continued into the open-label study (eculizumab/eculizumab: 56; placebo/eculizumab: 61). At week 26 of REGAIN, more eculizumab-treated patients than placebo-treated patients achieved a status of improved (60.7% vs 41.7%) or MM (25.0% vs 13.3%; common OR: 2.3; 95% CI: 1.1-4.5). After 130 weeks of eculizumab treatment, 88.0% of patients achieved improved status and 57.3% of patients achieved MM status. The safety profile of eculizumab was consistent with its known profile and no new safety signals were detected. CONCLUSION: Eculizumab led to rapid and sustained achievement of MM in patients with AChR+ refractory gMG. These findings support the use of eculizumab in this previously difficult-to-treat patient population. CLINICALTRIALSGOV IDENTIFIER: REGAIN, NCT01997229; REGAIN open-label extension, NCT02301624. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that, after 26 weeks of eculizumab treatment, 25.0% of adults with AChR+ refractory gMG achieved MM, compared with 13.3% who received placebo
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