Non-adiabatic radiative collapse of a relativistic star under different initial conditions

We examine the role of space-time geometry in the non-adiabatic collapse of a star dissipating energy in the form of radial heat flow, studying its evolution under different initial conditions. The collapse of a star with interior comprising of a homogeneous perfect fluid is compared with that of a star filled with inhomogeneous imperfect fluid with anisotropic pressure. Both the configurations are spherically symmetric, however, in the latter case, the physical space $t= constant$ of the configurations is assumed to be inhomogeneous endowed with spheroidal or pseudo-spheroidal geometry. It is observed that as long as the collapse is shear-free, its evolution depends only on the mass and size of the star at the onset of collapse.Comment: To appear in Pramana- j. of physic

Minimally processed fruit salad enriched with Lactobacillus acidophilus: Viability of anti-browning compounds in the preservation of color

Minimal processing promotes browning of some vegetal tissues due to cell membrane disruption, which results in the release of oxidative enzymes. This study evaluated the efficiency of citric acid, ascorbic acid, sodium metabisulfite and L-cysteine hydrochloride to retard enzymatic browning of minimally processed fruit salad and enriched this product with Lactobacillus acidophilus LA-5. Control treatment was fruit salad immersed in water. Polyphenol oxidase (PPO) and color (L*, a*, b*, index color - CI, browning index - BI, c*, and h°) were analyzed. The viability of L. acidophilus was also evaluated using Rogosa agar in fruit salads containing anti-browning compounds in higher concentrations. PPO presented a significant difference among control and fruit salad treated with ascorbic acid and L-cysteine hydrochloride, indicating the highest anti-browning activity of these compounds. The fruit color was affected by processing and storage time, with a reduction in the values of L* over time. Values of a*, c*, h° angle and CI indicated a predominance of red color in the fruit salad. Salads containing anti-browning compounds in higher concentrations presented viability of L. acidophilus above 7.43 log CFU/g up to the fifth day of storage, indicating that the product can be promised as probiotic. Thus, the fruit salad treated with anti-browning compounds has potential use as a probiotic carrier.Keywords: Fresh-cut fruits, color, ascorbic acid, vegetable matrix, probiotic culture

Association of Serum 25-Hydroxyvitamin D Deficiency with Risk of Incidence of Disability in Basic Activities of Daily Living in Adults >50 Years of Age.

BACKGROUND: Vitamin D deficiency compromises muscle function and is related to the etiology of several clinical conditions that can contribute to the development of disability. However, there are few epidemiological studies investigating the association between vitamin D deficiency and the incidence of disability. OBJECTIVES: We aimed to assess whether vitamin D deficiency is associated with the incidence of disability in basic activities of daily living (BADL) and to verify whether there are sex differences in this association. METHODS: A 4-y follow-up study was conducted involving individuals aged 50 y or older who participated in ELSA (English Longitudinal Study of Ageing). The sample consisted of 4814 participants free of disability at baseline according to the modified Katz Index. Vitamin D was assessed by serum 25-hydroxyvitamin D [25(OH)D] concentrations and the participants were classified as sufficient (>50 nmol/L), insufficient (>30 to ≤50 nmol/L), or deficient (≤30 nmol/L). Sociodemographic, behavioral, and clinical characteristics were also investigated. BADL were re-evaluated after 2 and 4 y of follow-up. The report of any difficulty to perform ≥1 BADL was considered as an incident case of disability. Poisson models stratified by sex and controlled for sociodemographic, behavioral, and clinical characteristics were carried out. RESULTS: After 4-y follow-up, deficient serum 25(OH)D was a risk factor for the incidence of BADL disability in both women (IRR: 1.53; 95% CI: 1.16, 2.03) and men (IRR: 1.44; 95% CI: 1.02, 2.02). However, insufficient serum 25(OH)D was not a risk factor for the incidence of BADL disability in either men or women. CONCLUSIONS: Independently of sex, deficient serum 25(OH)D concentrations were associated with increased risk of incidence of BADL disability in adults >50 y old and should be an additional target of clinical strategies to prevent disability in these populations

Dynapenia, abdominal obesity or both: which accelerates the gait speed decline most?

OBJECTIVE: to investigate whether the combination of dynapenia and abdominal obesity is worse than these two conditions separately regarding gait speed decline over time. METHODS: a longitudinal study was conducted involving 2,294 individuals aged 60 years or older free of mobility limitation at baseline (gait speed >0.8 m/s) who participated in the English Longitudinal Study of Ageing. Dynapenia was determined as a grip strength 102 cm for men and >88 cm for women. The participants were divided into four groups: non-dynapenic/non-abdominal obese (ND/NAO); only abdominal obese (AO); only dynapenic (D) and dynapenic/abdominal obese (D/AO). Generalised linear mixed models were used to analyse gait speed decline (m/s) as a function of dynapenia and abdominal obesity status over an 8-year follow-up period. RESULTS: over time, only the D/AO individuals had a greater gait speed decline (-0.013 m/s per year, 95% CI: -0.024 to -0.002; P < 0.05) compared to ND/NAO individuals. Neither dynapenia nor abdominal obesity only was associated with gait speed decline. CONCLUSION: dynapenic abdominal obesity is associated with accelerated gait speed decline and is, therefore, an important modifiable condition that should be addressed in clinical practice through aerobic and strength training for the prevention of physical disability in older adults

Gender differences in the association between adverse events in childhood or adolescence and the risk of premature mortality

To examine, by gender, the relationship between adverse events in childhood or adolescence and the increased risk of early mortality (before 80 years). The study sample included 941 participants of the English Longitudinal Study of Aging who died between 2007 and 2018. Data on socioeconomic status, infectious diseases, and parental stress in childhood or adolescence were collected at baseline (2006). Logistic regression models were adjusted by socioeconomic, behavioral and clinical variables. Having lived with only one parent (OR 3.79; p = 0.01), overprotection from the father (OR 1.12; p = 0.04) and having had an infectious disease in childhood or adolescence (OR 2.05; p = 0.01) were risk factors for mortality before the age of 80 in men. In women, overprotection from the father (OR 1.22; p < 0.01) was the only risk factor for mortality before the age of 80, whereas a low occupation of the head of the family (OR 0.58; p = 0.04) and greater care from the mother in childhood or adolescence (OR 0.86; p = 0.03) were protective factors. Independently of one’s current characteristics, having worse socioeconomic status and health in childhood or adolescence increased the risk of early mortality in men. Parental overprotection increased the risk of early mortality in both sexes, whereas maternal care favored longevity in women

Quantum dissipation and CP violation in MINOS

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)We use the open quantum systems framework to analyze the MINOS data and perform this analysis considering two different dissipative models. In the first model, the dissipative parameter describes the decoherence effect and in the second, the dissipative parameter describes other dissipative effects including decoherence. With the second model it is possible to study CP violation since we consider Majorana neutrinos. The analysis from the muon neutrino and antineutrino beam assigns different values to all the parameters of the models, but is consistent between them. Assuming that neutrinos are equivalent to antineutrinos, the global analysis presents a nonvanishing Majorana CP phase depending on the energetic parametrization of the dissipative parameter.895Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP [2012/00857-6

Is slowness a better discriminator of disability than frailty in older adults?

Background:The trajectory of incident disability that occurs simultaneously with changes in frailty status, as well as how much each frailty component contributes to this process in the different sexes, are unknown. The objective of this study is to analyse the trajectory of the incidence of disability on basic and instrumental activities of daily living (BADL and IADL) as a function of the frailty changes and their components by sex over time. // Methods: Longitudinal analyses of 1522 and 1548 of the English Longitudinal Study of Ageing study participants without BADL and IADL disability, respectively, and without frailty at baseline. BADL and IADL were assessed using the Katz and Lawton Scales and frailty by phenotype at 4, 8, and 12 years of follow-up. Generalized mixed linear models were calculated for the incidence of BADL and IADL disability, as an outcome, using changes in the state of frailty and its components, as the exposure, by sex in models fully adjusted for sociodemographic, behavioural, biochemical, and clinical characteristics. // Results: The mean age, at baseline, of the 1522 eligible individuals free of BADL and free of frailty was 68.1 ± 6.2 years (52.1% women) and of the 1548 individuals free IADL and free frailty was 68.1 ± 6.1 years (50.6% women). Women who became pre-frail had a higher risk of incidence of disability for BADL and IADL when compared with those who remained non-frail (P < 0.05). Men and women who became frail had a higher risk of incidence of disability regarding BADL and IADL when compared with those who remained non-frail (P < 0.05). Slowness was the only component capable of discriminating the incidence of disability regarding BADL and IADL when compared with those who remained without slowness (P < 0.05). Weakness and low physical activity level in men and exhaustion in women also discriminated the incidence of disability (P < 0.05). // Conclusions: Slowness is the main warning sign of functional decline in older adults. As its evaluation is easy, fast, and accessible, screening for this frailty component should be prioritized in different clinical contexts so that rehabilitation strategies can be developed to avoid the onset of disability

Radiating Shear-Free Gravitational Collapse with Charge

We present a new shear free model for the gravitational collapse of a spherically symmetric charged body. We propose a dissipative contraction with radiation emitted outwards. The Einstein field equations, using the junction conditions and an ansatz, are integrated numerically. A check of the energy conditions is also performed. We obtain that the charge delays the black hole formation and it can even halt the collapse.Comment: 22 pages, 9 figures. It has been corrected several typos and included several references. Accepted for publication in GR

Five-year review of an international clinical research-training program

The exponential increase in clinical research has profoundly changed medical sciences. Evidence that has accumulated in the past three decades from clinical trials has led to the proposal that clinical care should not be based solely on clinical expertise and patient values, and should integrate robust data from systematic research. As a consequence, clinical research has become more complex and methods have become more rigorous, and evidence is usually not easily translated into clinical practice. Therefore, the instruction of clinical research methods for scientists and clinicians must adapt to this new reality. To address this challenge, a global distance-learning clinical research-training program was developed, based on collaborative learning, the pedagogical goal of which was to develop critical thinking skills in clinical research. We describe and analyze the challenges and possible solutions of this course after 5 years of experience (2008-2012) with this program. Through evaluation by students and faculty, we identified and reviewed the following challenges of our program: 1) student engagement and motivation, 2) impact of heterogeneous audience on learning, 3) learning in large groups, 4) enhancing group learning, 5) enhancing social presence, 6) dropouts, 7) quality control, and 8) course management. We discuss these issues and potential alternatives with regard to our research and background