899 resultados para Demographic Aging
Resumo:
Background Self-reported tendinitis/tenosynovitis was evaluated by gender, age group, skin color, family income, and educational and psychological status. Methods The study was carried out in a representative sample of formally contracted Brazilian workers from a household survey. A total of 54,660 participants were included. Occupations were stratified according to estimated prevalences of self-reported injuries. Non-conditional logistic regression was performed, and all variables were analyzed in two occupational groups. Results The overall prevalence rate of tendinitis/tenosynovitis was 3.1%: 5.5% in high-prevalence occupations (n=10,726); and 2.5% in low-prevalence occupations (n=43,934). White female workers between the ages of 45 and 64 years and at a higher socioeconomic level were more likely to report tendinitis/tenosynovitis regardless of their occupational category. An adjusted OR = 3.59 [95% CI: 3.15-4.09] was found between tendinitis/tenosynovitis and psychological status. Conclusion Among formally contracted Brazilian workers, higher income can imply greater physical and psychological demands that, regardless of occupational stratum, increase the risk of tendinitis/tenosynovitis. Am. J. Ind. Med. 53:72-79, 2010. (C) 2009 Wiley-Liss, Inc.
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Previous studies found students who both work and attend school undergo a partial sleep deprivation that accumulates across the week. The aim of the present study was to obtain information using a questionnaire on a number of variables (e.g., socio-demographics, lifestyle, work timing, and sleep-wake habits) considered to impact on sleep duration of working (n = 51) and non-working (n = 41) high-school students aged 14-21 yrs old attending evening classes (19:00-22:30h) at a public school in the city of Sao Paulo, Brazil. Data were collected for working days and days off. Multiple linear regression analyses were performed to assess the factors associated with sleep duration on weekdays and weekends. Work, sex, age, smoking, consumption of alcohol and caffeine, and physical activity were considered control variables. Significant predictors of sleep duration were: work (p < 0.01), daily work duration (8-10h/day; p < 0.01), sex (p = 0.04), age 18-21 yrs (0.01), smoking (p = 0.02) and drinking habits (p = 0.03), irregular physical exercise (p < 0.01), ease of falling asleep (p = 0.04), and the sleep-wake cycle variables of napping (p < 0.01), nocturnal awakenings (p < 0.01), and mid-sleep regularity (p < 0.01). The results confirm the hypotheses that young students who work and attend school showed a reduction in night-time sleep duration. Sleep deprivation across the week, particularly in students working 8-10h/day, is manifested through a sleep rebound (i.e., extended sleep duration) on Saturdays. However, the different roles played by socio-demographic and lifestyle variables have proven to be factors that intervene with nocturnal sleep duration. The variables related to the sleep-wake cyclenaps and night awakeningsproved to be associated with a slight reduction in night-time sleep, while regularity in sleep and wake-up schedules was shown to be associated with more extended sleep duration, with a distinct expression along the week and the weekend. Having to attend school and work, coupled with other socio-demographic and lifestyle factors, creates an unfavorable scenario for satisfactory sleep duration.
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Recent global assessments have shown the limited coverage of protected areas across tropical biotas, fuelling a growing interest in the potential conservation services provided by anthropogenic landscapes. Here we examine the geographic distribution of biological diversity in the Atlantic Forest of South America, synthesize the most conspicuous forest biodiversity responses to human disturbances, propose further conservation initiatives for this biota, and offer a range of general insights into the prospects of forest species persistence in human-modified tropical forest landscapes worldwide. At the biome scale, the most extensive pre-Columbian habitats across the Atlantic Forest ranged across elevations below 800 masl, which still concentrate most areas within the major centers of species endemism. Unfortunately, up to 88% of the original forest habitat has been lost, mainly across these low to intermediate elevations, whereas protected areas are clearly skewed towards high elevations above 1200 masl. At the landscape scale, most remaining Atlantic Forest cover is embedded within dynamic agro-mosaics including elements such as small forest fragments, early-to-late secondary forest patches and exotic tree mono-cultures. In this sort of aging or long-term modified landscapes, habitat fragmentation appears to effectively drive edge-dominated portions of forest fragments towards an early-successional system, greatly limiting the long-term persistence of forest-obligate and forest-dependent species. However, the extent to which forest habitats approach early-successional systems, thereby threatening the bulk of the Atlantic Forest biodiversity, depends on both past and present landscape configuration. Many elements of human-modified landscapes (e.g. patches of early-secondary forests and tree mono-cultures) may offer excellent conservation opportunities, but they cannot replace the conservation value of protected areas and hitherto unprotected large patches of old-growth forests. Finally, the biodiversity conservation services provided by anthropogenic landscapes across Atlantic Forest and other tropical forest regions can be significantly augmented by coupling biodiversity corridor initiatives with biota-scale attempts to plug existing gaps in the representativeness of protected areas. (C) 2010 Elsevier Ltd. All rights reserved.
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The vesicourethral junction comprising the vesical trigone, is relevant in setting and positioning of the urinary bladder, along with the vesical neck, fixed by lateral ligaments of the bladder and tendinous arch of the pelvis fascia. Namely, the puboprostatic ligament (men) and the pubovesical (women). The circular set elastic fibers in this junction are important and valuable in the elasticity and plasticity of the area, allowing quick expansion and withdrawal with the flow of urine, and associated to smooth muscle tissue and nerve control form an important collective to maintain urinary continence. The objective of the present study is to describe the elastic system in the vesicouretral junction in relation to aging and its involvement in the states of urinary continence and incontinence, as well as the study of the vesicouretral junction in various age groups while evaluating with electron transmission microscopy. To carry out the study, 12 Wistar rats were used, divided into groups: neonate (4 animals), adult group (4 animals) and aged group (4 animals). Electron transmission microscopy with use of tanic acid technique associated to glutaraldehyde fixation, satisfactorily showed the extreme structural differences between mature elaunin and oxytalan fibers present between intercelular spaces and bundles of collagen fibers. The phases of elastogenesis in neonate animals and degradation of the elastic system of older animals were also evaluated.
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Long-term memory, a persistent form of synaptic plasticity, requires translation of a subset of mRNA present in neuronal dendrites during a short and critical period through a mechanism not yet fully elucidated. Western blotting analysis revealed a high content of eukaryotic translation initiation factor 5A (eIF5A) in the brain of neonatal rats, a period of intense neurogenesis rate, differentiation and synaptic establishment, when compared to adult rats. Immunohistochemistry analysis revealed that eIF5A is present in the whole brain of adult rats showing a variable content among the cells from different areas (e.g. cortex, hippocampus and cerebellum). A high content of eIF5A in the soma and dendrites of Purkinje cells, key neurons in the control of motor long-term memory in the cerebellum, was observed. Detection of high eIF5A content was revealed in dendritic varicosities of Purkinje cells. Evidence is presented herein that a reduction of eIF5A content is associated to brain aging. (C) 2008 Elsevier B.V. All rights reserved.
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Aging can lead to cognitive, affective, learning, memory and motor deficits. Since the cerebellum and glutamatergic neurotransmission are involved in several of those functions, the present work aimed at studying the expression of AMPA and NMDA glutamate receptor subunits in the chick cerebellum during aging. Young (30 days old) and aged (ca. 4 years old) chickens (Gallus gallus) were used in order to evaluate the expression of GluR1, GluR2/3 and NR1 subunits. The cerebella of young and aged chickens were subjected to immunohistochemical and immunoblotting techniques. Numbers of GluR1, GluR2/3 and NR1-positive cells and optical density of the immunoblotting data were analyzed and submitted to statistical analysis using ANOVA and the Bonferroni post hoc test. Mean density of Purkinje cells stained for Giemsa, GluR1, GluR2/3 and NR1 in the cerebellum all showed a statistically significant decrease in aged animals when compared to the young animals (Giemsa, P < 0.01; GluRs and NR1, P < 0.03). However, the ratio of GluR1 and GluR2/3-positive Purkinje cells in relation the total number of Purkinje cells found in each time point decreased with aging (ca. 10%), whereas the ratio of NR1-positive cells increased (ca. 9%). The immunoblotting data showed a significant decrease of GluR1 (ca. 66%) and GluR2/3 (ca. 55%) protein expression with aging, but did not reveal changes for NR1. Our data suggest that aging can lead to differential changes in the pattern of expression of glutamate receptor subunits, which can underlie at least part of the cognitive and motor disorders found in aged animals. (c) 2010 Elsevier Ireland Ltd. All rights reserved.
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Background: There is general consensus that the effects of intrinsic aging on the oral mucosa are relatively small, though potentially important to understanding the pathologies present in the aged animals. Objective: In this paper, the development of dorsal surface of rat tongue was examined using transmission electron microscopy (TEM) and high-resolution scanning electron microscopy (HRSEM) in order to understand the age-related structural and ultrastructural changes experimentally. Methods: In this study, we used female rats 75 and 720 days old (adult and aging). Tissues of rat tongue were prepared and the specimens submitted to HRSEM and TEM techniques. Results: The analysis of HRSEM and TEM demonstrated that the same characteristic keratinous epithelium was found in aging animals, however with some modifications. Conclusion: We agree that there are obvious changes in the oral mucosa with aging and these modifications can be observed starting from the ultrastructural aspects. Copyright (C) 2009 S. Karger AG, Basel
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We consider a non-equilibrium three-state model whose dynamics is Markovian and displays the same symmetry as the three-state Potts model, i.e. the transition rates are invariant under the cyclic permutation of the states. Unlike the Potts model, detailed balance is, in general, not satisfied. The aging and the stationary properties of the model defined on a square lattice are obtained by means of large-scale Monte Carlo simulations. We show that the phase diagram presents a critical line, belonging to the three-state Potts universality class, that ends at a point whose universality class is that of the Voter model. Aging is considered on the critical line, at the Voter point and in the ferromagnetic phase.
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For many learning tasks the duration of the data collection can be greater than the time scale for changes of the underlying data distribution. The question we ask is how to include the information that data are aging. Ad hoc methods to achieve this include the use of validity windows that prevent the learning machine from making inferences based on old data. This introduces the problem of how to define the size of validity windows. In this brief, a new adaptive Bayesian inspired algorithm is presented for learning drifting concepts. It uses the analogy of validity windows in an adaptive Bayesian way to incorporate changes in the data distribution over time. We apply a theoretical approach based on information geometry to the classification problem and measure its performance in simulations. The uncertainty about the appropriate size of the memory windows is dealt with in a Bayesian manner by integrating over the distribution of the adaptive window size. Thus, the posterior distribution of the weights may develop algebraic tails. The learning algorithm results from tracking the mean and variance of the posterior distribution of the weights. It was found that the algebraic tails of this posterior distribution give the learning algorithm the ability to cope with an evolving environment by permitting the escape from local traps.
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BACKGROUND: This study evaluated demographic profiles and prevalence of serologic markers among donors who used confidential unit exclusion (CUE) to assess the effectiveness of CUE and guide public policies regarding the use of CUE for enhancing safety versus jeopardizing the blood supply by dropping CUE. STUDY DESIGN AND METHODS: We conducted a cross-sectional analysis of whole blood donations at a large public blood center in Sao Paulo from July 2007 through June 2009, compared demographic data, and confirmed serologic results among donors who used and who have never used CUE (CUE never). RESULTS: There were 265,550 whole blood units collected from 181,418 donors from July 2007 through June 2009. A total of 9658 (3.6%) units were discarded, 2973 (1.1%) because CUE was used at the current donation (CUE now) and 6685 (2.5%) because CUE was used in the past (CUE past). The CUE rate was highest among donors with less than 8 years of education (odds ratio [OR], 2.78; 95% confidence interval [CI], 2.51-3.08). CUE now donations were associated with higher positive infectious disease marker rates than CUE never donations (OR, 1.41; CI, 1.13-1.77), whereas CUE past donations were not (OR, 1.04; CI, 0.75-1.45). CONCLUSION: The CUE process results in a high rate of unit discard. CUE use on an individual donation appears predictive of a high-risk marker-positive donation and, thus, appears to contribute modestly to blood safety. The policy of discarding units from donors who have previously CUE-positive donations does not improve safety and should be discontinued.
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Oxidative DNA damage plays a role in disease development and the aging process. A prominent participant in orchestrating the repair of oxidative DNA damage, particularly single-strand breaks, is the scaffold protein XRCC1. A series of chronological and biological aging parameters in XRCC1 heterozygous (HZ) mice were examined. HZ and wild-type (WT) C57BL/6 mice exhibit a similar median lifespan of similar to 26 months and a nearly identical maximal life expectancy of similar to 37 months. However, a number of HZ animals (7 of 92) showed a propensity for abdominal organ rupture, which may stem from developmental abnormalities given the prominent role of XRCC1 in endoderm and mesoderm formation. For other end-points evaluated-weight, fat composition, blood chemistries, condition of major organs, tissues and relevant cell types, behavior, brain volume and function, and chromosome and telomere integrity-HZ mice exhibited by-and-large a normal phenotype. Treatment of animals with the alkylating agent azoxymethane resulted in both liver toxicity and an increased incidence of precancerous lesions in the colon of HZ mice. Our study indicates that XRCC1 haploinsufficiency in mammals has little effect on chronological longevity and many key biological markers of aging in the absence of environmental challenges, but may adversely affect normal animal development or increase disease susceptibility to a relevant genotoxic exposure.
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Concentrated solar power systems are expected to be sited in desert locations where the direct normal irradiation is above 1800 kWh/m2.year. These systems include large solar collector assemblies, which account for a significant share of the investment cost. Solarreflectors are the main components of these solar collector assemblies and dust/sand storms may affect their reflectance properties, either by soiling or by surface abrasion. While soiling can be reverted by cleaning, surface abrasion is a non reversible degradation.The aim of this project was to study the accelerated aging of second surface silvered thickglass solar reflectors under simulated sandstorm conditions and develop a multi-parametric model which relates the specular reflectance loss to dust/sand storm parameters: wind velocity, dust concentration and time of exposure. This project focused on the degradation caused by surface abrasion.Sandstorm conditions were simulated in a prototype environmental test chamber. Material samples (6cm x 6cm) were exposed to Arizona coarse test dust. The dust stream impactedthese material samples at a perpendicular angle. Both wind velocity and dust concentrationwere maintained at a stable level for each accelerated aging test. The total exposure time in the test chamber was limited to 1 hour. Each accelerated aging test was interrupted every 4 minutes to measure the specular reflectance of the material sample after cleaning.The accelerated aging test campaign had to be aborted prematurely due to a contamination of the dust concentration sensor. A robust multi-parametric degradation model could thus not be derived. The experimental data showed that the specular reflectance loss decreasedeither linearly or exponentially with exposure time, so that a degradation rate could be defined as a single modeling parameter. A correlation should be derived to relate this degradation rate to control parameters such as wind velocity and dust/sand concentration.The sandstorm chamber design would have to be updated before performing further accelerated aging test campaigns. The design upgrade should improve both the reliability of the test equipment and the repeatability of accelerated aging tests. An outdoor exposure test campaign should be launched in deserts to learn more about the intensity, frequencyand duration of dust/sand storms. This campaign would also serve to correlate the results of outdoor exposure tests with accelerated exposure tests in order to develop a robust service lifetime prediction model for different types of solar reflector materials.
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Although the need to make health services more accessible to persons who have migrated has been identified, knowledge about health-promotion programs (HPPs) from the perspective of older persons born abroad is lacking. This study explores the design experiences and content implemented in an adapted version of a group-based HPP developed in a researcher-community partnership. Fourteen persons aged 70-83 years or older who had migrated to Sweden from Finland or the Balkan Peninsula were included. A grounded theory approach guided the data collection and analysis. The findings showed how participants and personnel jointly helped raise awareness. The participants experienced three key processes that could open doors to awareness: enabling community, providing opportunities to understand and be understood, and confirming human values and abilities. Depending on how the HPP content and design are being shaped by the group, the key processes could both inhibit or encourage opening doors to awareness. Therefore, this study provides key insights into how to enable health by deepening the understanding of how the exchange of health-promoting messages is experienced to be facilitated or hindered. This study adds to the scientific knowledge base of how the design and content of HPP may support and recognize the capabilities of persons aging in the context of migration.
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Over the past decade, universities were able to grow revenue primarily by growing enrollment and increasing net tuition per student. But demographic and economic changes will make it increasingly difficult for all but a handful of institutions to grow tuition revenue at historic rates. Despite rising access rates, demographic projections suggest that the number of high school graduates will decline over the coming decade, leading to a dramatic drop-off in the overall rate of enrollment growth. The traditional population of 18- to 22-year-olds will remain a majority at most institutions, but enrollment growth will come primarily from other student segments. Populations such as community college transfers, international undergraduates, professional master’s students, and adult degree completers offer the best opportunities to grow enrollment and tuition revenue. Serving them well requires significant investments, new organizational models, and cultural change on campus. This can be done in a financially sustainable way—fulfilling the university’s mission to serve a diverse range of students while providing financial resources to support the core. This brief analyzes the forces that will shape higher education over the next decade and highlights the strategies and competencies that colleges and universities will need to be successful.
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This article investigates the causes in the reduction of labor force participation of the old. We argue that the changes in social security policy, in technology and in demography may account for most of the changes in retirement over the second part of the last century in the U.S. economy. We develop a dynamic general equilibrium model with endogenous retirement that embeds social security legislation. The model is able to match very closely the increase in the retirement rate of males aged 65 and older. It also quanti es the isolated impact on retirement and on the solvency of the social security system of the di¤erent factors. The model suggests that technological and demographic changes had a strong in uence on retirement, so that it would have increased signi cantly even if the social security rules had not changed. However, as the latter became much more generous in the past, changes in social security policy can account not only for a sizeable part of the expansion of retirement, but also for the most of the observed increase in the social security expenses as a share of GDP.