230 research outputs found
Expression of CD44 molecules and CD44 ligands during human thymic fetal development: expression of CD44 isoforms is developmentally regulated
It has recently been recognized that CD44 comprises a large family of alternatively spliced forms.In the thymus, CD44 has been postulated to play an important role in immature T cell migration and maturation. In this paper, we have studied the expression of CD44 molecules and two CD44 ligands, hyaluronan (HA) and fibronectin (FN), during human thymic fetal development. We found that mAbs against all CD44 isoforms (A3D8 or A1G3) reacted with both thymic epithelial (TE) cells and thymocytes beginning at the time of initial colonization of the human thymus by hematopoietic stem cells at 8.2 weeks of fetal gestation. However, mAbs specific for splice variants of CD44 containing membrane-proximal inserts (11.24, 11.10 and 11.9) reacted only with terminally differentiated TE cells in and around Hassall's bodies beginning at 16-19 weeks of fetal gestation. Studies of differentiated versus undifferentiated TE cells in vitro confirmed the selective expression of CD44 variant isoforms on terminally differentiated TE cells. Expression of HA and FN was determined by fluorescence microscopy using either biotlnylated-HA binding protein or an anti-FN mAb. We found that whereas FN was present throughout the human fetal thymus beginning at 8.2 weeks, HA was not present until 16 weeks of gestational age. These data demonstrate the differential expression of standard versus variant CD44 isoforms during thymic ontogeny and implicate CD44 interactions with ligands other than HA as important in the earlier stages of humanthymus developmen
Short communication: relationship between body growth and mammary development in dairy heifers
Our objective was to determine if prepubertal rate of body weight (BW) gain, independent of diet, was related to mammary development of dairy heifers. Data from two studies recently conducted at Michigan State University were used to identify factors, within a dietary treatment group, that would account for variation in first lactation milk production or amount of mammary parenchymal DNA at the time of puberty. Factors analyzed for variation in milk production during first lactation were: postpartum BW, prepubertal BW gain, gestational BW gain, postpartum BW gain, body condition score (BCS) at breeding, and BCS at calving. Factors analyzed for variation in mammary parenchymal DNA at puberty were: BW at slaughter, age at puberty, prepubertal BW gain and body protein and body fat content at slaughter. For both analyses, prepubertal BW gain did not account for any of the variation in mammary development. The only significant covariate for the milk production model (r2 = 0.44) was BCS at breeding. Similarly, the only significant covariate in the parenchymal DNA model (r2 = 0.22) was body fat content at slaughter. These results suggest that, within a dietary treatment, heifers that grow faster do not have impaired mammary development, and increased body fatness may be a better predictor of impaired mammary development than BW gain
Short communication: relationship between body growth and mammary development in dairy heifers
Our objective was to determine if prepubertal rate of body weight (BW) gain, independent of diet, was related to mammary development of dairy heifers. Data from two studies recently conducted at Michigan State University were used to identify factors, within a dietary treatment group, that would account for variation in first lactation milk production or amount of mammary parenchymal DNA at the time of puberty. Factors analyzed for variation in milk production during first lactation were: postpartum BW, prepubertal BW gain, gestational BW gain, postpartum BW gain, body condition score (BCS) at breeding, and BCS at calving. Factors analyzed for variation in mammary parenchymal DNA at puberty were: BW at slaughter, age at puberty, prepubertal BW gain and body protein and body fat content at slaughter. For both analyses, prepubertal BW gain did not account for any of the variation in mammary development. The only significant covariate for the milk production model (r2 = 0.44) was BCS at breeding. Similarly, the only significant covariate in the parenchymal DNA model (r2 = 0.22) was body fat content at slaughter. These results suggest that, within a dietary treatment, heifers that grow faster do not have impaired mammary development, and increased body fatness may be a better predictor of impaired mammary development than BW gain
Coherent States of the SU(N) groups
Coherent states of the groups are constructed explicitly and
their properties are investigated. They represent a nontrivial generalization
of the spining of the group. The are parametrized by the
points of the coset space, which is, in that particular case, the projective
space and plays the role of the phase space of a corresponding
classical mechanics. The possess of a minimum uncertainty, they minimize
an invariant dispersion of the quadratic Casimir operator. The classical limit
is ivestigated in terms of symbols of operators. The role of the Planck
constant playes , where is the signature of the representation.
The classical limit of the so called star commutator generates the Poisson
bracket in the phase space. The logarithm of the modulus of the
overlapping, being interpreted as a symmetric in the space, gives the
Fubini-Study metric in . The constructed are useful for the
quasi-classical analysis of the quantum equations of the gauge
symmetric theories.Comment: 19pg, IFUSP/P-974 March/199
Association of Accelerometry-Measured Physical Activity and Cardiovascular Events in Mobility-Limited Older Adults: The LIFE (Lifestyle Interventions and Independence for Elders) Study.
BACKGROUND:Data are sparse regarding the value of physical activity (PA) surveillance among older adults-particularly among those with mobility limitations. The objective of this study was to examine longitudinal associations between objectively measured daily PA and the incidence of cardiovascular events among older adults in the LIFE (Lifestyle Interventions and Independence for Elders) study. METHODS AND RESULTS:Cardiovascular events were adjudicated based on medical records review, and cardiovascular risk factors were controlled for in the analysis. Home-based activity data were collected by hip-worn accelerometers at baseline and at 6, 12, and 24 months postrandomization to either a physical activity or health education intervention. LIFE study participants (n=1590; age 78.9±5.2 [SD] years; 67.2% women) at baseline had an 11% lower incidence of experiencing a subsequent cardiovascular event per 500 steps taken per day based on activity data (hazard ratio, 0.89; 95% confidence interval, 0.84-0.96; P=0.001). At baseline, every 30 minutes spent performing activities â„500 counts per minute (hazard ratio, 0.75; confidence interval, 0.65-0.89 [P=0.001]) were also associated with a lower incidence of cardiovascular events. Throughout follow-up (6, 12, and 24 months), both the number of steps per day (per 500 steps; hazard ratio, 0.90, confidence interval, 0.85-0.96 [P=0.001]) and duration of activity â„500 counts per minute (per 30 minutes; hazard ratio, 0.76; confidence interval, 0.63-0.90 [P=0.002]) were significantly associated with lower cardiovascular event rates. CONCLUSIONS:Objective measurements of physical activity via accelerometry were associated with cardiovascular events among older adults with limited mobility (summary score >10 on the Short Physical Performance Battery) both using baseline and longitudinal data. CLINICAL TRIAL REGISTRATION:URL: http://www.clinicaltrials.gov. Unique identifier: NCT01072500
Comparison of alternative risk adjustment measures for predictive modeling: high risk patient case finding using Taiwan's National Health Insurance claims
<p>Abstract</p> <p>Background</p> <p>Predictive modeling presents an opportunity to contain the expansion of medical expenditures by focusing on very few people. Evaluation of how risk adjustment models perform in predictive modeling in Taiwan or Asia has been rare. The aims of this study were to evaluate the performance of different risk adjustment models (the ACG risk adjustment system and prior expenditures) in predictive modeling, using Taiwan's National Health Insurance (NHI) claims data, and to compare characteristics of potentially high-expenditure subjects identified through different models.</p> <p>Methods</p> <p>A random sample of NHI enrollees continuously enrolled in 2002 and 2003 (n = 164,562) was selected. Health status measures and total expenditures derived from 2002 NHI claims data were used to predict the possibility of becoming 2003 top users. Statistics-based indicators (C-statistics, sensitivity, & Predictive Positive Value) and characteristics of identified top groups by different models (expenditures and prevalence of manageable diseases) were presented.</p> <p>Results</p> <p>Both diagnosis-based and prior expenditures models performed much better than the demographic model. Diagnosis-based models were better in identifying top users with manageable diseases; prior expenditures models were better in statistics-based indicators and identifying people with higher average expenditures. Prior expenditures status could correctly identify more actual top users than diagnosis-based or demographic models. The proportions of actual top users that could be identified by diagnosis-based models alone were much lower than that identified by prior expenditures status.</p> <p>Conclusions</p> <p>Predicted top users identified by different models have different characteristics and there is little agreement between modes regarding which groups would be potentially top users; therefore, which model to use should depend on the purpose of predictive modeling. Prior expenditures are a more powerful tool than diagnosis-based risk adjusters in terms of correctly identifying more actual high expenditures users. There is still much room left for improvement of diagnosis-based models in predictive modeling.</p
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Life satisfaction and confidence in national institutions: evidence from South America
A number of South American countries experienced turbulent democratic, political and economic upheaval over the last 40 years in the form of coup dâĂ©tats in the 1970s, tumultuous elections, and repeated severe economic crises, some of which happened fairly recently. Starting in 2010, a number of court proceedings across the region have made past military coup dâĂ©tats the focus of national conversations. South American citizens may, therefore, have lost confidence in national institutions that have repeatedly disappointed their trust and expectations; a situation with potentially detrimental effects on their well-being. Using eight waves of the Gallup World Poll collected between 2009 and 2016 across ten South American countries, we investigate to what extent peopleâs confidence in financial institutions, the honesty of elections, the military, the judicial system, the national government and the police is associated with peopleâs current and expectation of future life satisfaction. We find that people who report confidence in these six institutions rate their current and expected life satisfaction, on average, to be higher than those who lack these types of institutional confidence, even after controlling for demographic factors and macroeconomic indicators. In addition, we investigate changes over time for all six measures of confidence in institutions as well as for current and expectation of future life satisfaction. Our results suggest that governmentsâ investments in well-functioning institutions may contribute positively to subjective well-being in a society. However, our analysis is correlational and we thus cannot rule out reverse causality
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How do i know who you think you are? A review of research methods on organizational identity
The notion of organizational identity was introduced in management studies in 1985. In the following 25 years, a vibrant debate about how to conceptualize organizational identities and related themes (multiple identities, identity change, interrelations between identity, image and culture) does not seem to have corresponded to explicit reflections about specific methodological issues. In this paper, the authors inductively review research methods adopted by studies of organizational identity published in top-level journals, with the purpose of deriving insights about the current status of research practices, uncovering their often tacit ontological and epistemological assumptions, and stimulating discussion about their possible evolution
Perioperative mortality after hemiarthroplasty related to fixation method: A study based on the Australian Orthopaedic Association National Joint Replacement Registry
Background and purpose: The appropriate fixation method for hemiarthroplasty of the hip as it relates to implant survivorship and patient mortality is a matter of ongoing debate. We examined the influence of fixation method on revision rate and mortality.----- ----- Methods: We analyzed approximately 25,000 hemiarthroplasty cases from the AOA National Joint Replacement Registry. Deaths at 1 day, 1 week, 1 month, and 1 year were compared for all patients and among subgroups based on implant type.----- ----- Results: Patients treated with cemented monoblock hemiarthroplasty had a 1.7-times higher day-1 mortality compared to uncemented monoblock components (p < 0.001). This finding was reversed by 1 week, 1 month, and 1 year after surgery (p < 0.001). Modular hemiarthroplasties did not reveal a difference in mortality between fixation methods at any time point.----- ----- Interpretation: This study shows lower (or similar) overall mortality with cemented hemiarthroplasty of the hip
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The subjective well-being political paradox: Evidence from Latin America
The subjective well-being political paradox describes the observation that individuals are on average more satisfied with their lives in welfare states than under right-leaning (conservative) governments, which are less likely to promote welfare policies; however, at the individual level, people who identify as leaning politically more to the right show higher levels of life satisfaction than those who describe themselves as leaning to the left. This subjective well-being political paradox has previously been observed in Europe. The present study investigates whether this paradox can also be found across 18 Latin American countries by using data from 9 waves of the LatinobarĂłmetro survey. In addition to life satisfaction, we further consider respondentsâ self-rated ability to meet their financial needs in a satisfactory manner, which can be seen as a proxy for satisfaction with income. Latin America is an interesting region to study this question because of its political history and the emergence of left-leaning governments during the last fifteen years. We find that people report higher life satisfaction and a better ability to meet their financial needs under left-leaning governments compared to centre and right-leaning governments. In contrast, conservative individuals report higher financial and overall well-being than liberal individuals, which confirms the subjective well-being political paradox that was also found in Europe. Our analysis includes controls for macroeconomic indicators, such as inflation and unemployment rates and GDP per capita as well as socio-demographic factors
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