274 research outputs found
Different evolutionary pathways underlie the morphology of wrist bones in hominoids
BACKGROUND
The hominoid wrist has been a focus of numerous morphological analyses that aim to better understand long-standing questions about the evolution of human and hominoid hand use. However, these same analyses also suggest various scenarios of complex and mosaic patterns of morphological evolution within the wrist and potentially multiple instances of homoplasy that would benefit from require formal analysis within a phylogenetic context.We identify morphological features that principally characterize primate - and, in particular, hominoid (apes, including humans) - wrist evolution and reveal the rate, process and evolutionary timing of patterns of morphological change on individual branches of the primate tree of life. Linear morphological variables of five wrist bones - the scaphoid, lunate, triquetrum, capitate and hamate - are analyzed in a diverse sample of extant hominoids (12 species, 332 specimens), Old World (8 species, 43 specimens) and New World (4 species, 26 specimens) monkeys, fossil Miocene apes (8 species, 20 specimens) and Plio-Pleistocene hominins (8 species, 18 specimens).
RESULT
Results reveal a combination of parallel and synapomorphic morphology within haplorrhines, and especially within hominoids, across individual wrist bones. Similar morphology of some wrist bones reflects locomotor behaviour shared between clades (scaphoid, triquetrum and capitate) while others (lunate and hamate) indicate clade-specific synapomorphic morphology. Overall, hominoids show increased variation in wrist bone morphology compared with other primate clades, supporting previous analyses, and demonstrate several occurrences of parallel evolution, particularly between orangutans and hylobatids, and among hominines (extant African apes, humans and fossil hominins).
CONCLUSIONS
Our analyses indicate that different evolutionary processes can underlie the evolution of a single anatomical unit (the wrist) to produce diversity in functional and morphological adaptations across individual wrist bones. These results exemplify a degree of evolutionary and functional independence across different wrist bones, the potential evolvability of skeletal morphology, and help to contextualize the postcranial mosaicism observed in the hominin fossil record
Moral hazard and the demand for health services: A matching estimator approach
We estimate the impact of extra health insurance coverage beyond a National Health System on the demand for several health services. Traditionally, the literature has tried to deal with the endogeneity of the private (extra) insurance decision by finding instrumental variables. Since a priori instrumental variables are hard to find we take a different approach. We focus on the most common health insurance plan in Portugal, ADSE, which is given to all civil servants and their dependents. We argue that this insurance is exogenous, i.e., not correlated with the beneficiaries’ health status. This identifying assumption allows us to estimate the impact of having ADSE coverage on the demand for three different health services using a matching estimator technique. The health services used are number of visits, number of blood and urine tests, and the probability of visiting a dentist. Results show large positive effects of ADSE coverage for number of visits and tests among the young (18–30 years old) but only the latter is statistically significantly different from zero. The effects represent 21.8% and 30% of the average number of visits and tests for the young. On the contrary, we find no evidence of moral hazard on the probability of visiting a dentist.Publicad
Moral hazard and the demand for health services: a matching estimator approach
We estimate the impact of health insurance coverage beyond National Health Insurance on the demand for several health services. Traditionally, the literature has tried to deal with the endogeneity of the private (extra) insurance decision by finding instrumental variables. Since a priori instrumental variables are hard to find we take a different approach. We focus on the most common health insurance plan in Portugal, ADSE, which is given to all civil servants and their dependants. We argue this insurance is exogenous i.e. not correlated with beneficiaries’ health status. This identifying assumption allows us to estimate the impact of having ADSE coverage on three different health services using a matching estimator technique. The health services used are: number of visits, number of blood and urine tests, and the probability of visiting a dentist. Results show large positive effects of ADSE for number of visits and tests among the young (18 to 30 years old) but only the latter is statistically significantly different from zero. The effects represent 21.8 and 30% of the average number of visits and tests for the young. On the contrary, we find no evidence of moral hazard on the probability of visiting a dentist
MORAL HAZARD AND THE DEMAND FOR HEALTH SERVICES: A MATCHING ESTIMATOR APPROACH
In this paper we estimate the impact of health insurance coverage beyond National Health Insurance on the demand for several health services. Traditionally, the literature has tried to deal with the endogeneity of the private (extra) insurance decision by finding instrumental variables. It is hard to think, however, of any variable that a priori would be a good instrument and, therefore, we take a different approach. We concentrate on the most common health insurance plan in the Portuguese Health Survey, (ADSE), which is given to all civil servants and their dependants. We argue that this insurance is exogenous for most people i.e. not correlated with their health status. Under this identifying assumption we estimate the impact of having ADSE coverage on three different health services using a matching estimator technique. The measures of demand for health services are number of visits, number of blood and urine tests, and the probability of visiting a dentist. Preliminary results show large effects of ADSE for number of visits and tests among the young (18 to 30 years old) but only for tests are these effects statistically significantly different from zero. The magnitude of the effects represent 21.8 and 30 percent of the average number of visits and tests for the young. On the contrary we find no evidence of moral hazard on the probability of visiting a dentist. Finally, we argue that there is evidence of a positive cumulative effect of ADSE over the years.
Moral hazard and the demand for health services: A matching estimator approach.
We estimate the impact of extra health insurance coverage beyond a National Health System on the demand for several health services. Traditionally, the literature has tried to deal with the endogeneity of the private (extra) insurance decision by finding instrumental variables. Since a priori instrumental variables are hard to find we take a different approach. We focus on the most common health insurance plan in Portugal, ADSE, which is given to all civil servants and their dependents. We argue that this insurance is exogenous, i.e., not correlated with the beneficiaries’ health status. This identifying assumption allows us to estimate the impact of having ADSE coverage on the demand for three different health services using a matching estimator technique. The health services used are number of visits, number of blood and urine tests, and the probability of visiting a dentist. Results show large positive effects of ADSE coverage for number of visits and tests among the young (18–30 years old) but only the latter is statistically significantly different from zero. The effects represent 21.8% and 30% of the average number of visits and tests for the young. On the contrary, we find no evidence of moral hazard on the probability of visiting a dentist.Demand for health services; Matching estimator; Moral hazard; Portuguese health system;
Automatic segmentation of cerebral infarcts in follow-up computed tomography images with convolutional neural networks
Background and purpose: Infarct volume is a valuable outcome measure in treatment trials of acute ischemic stroke and is strongly associated with functional outcome. Its manual volumetric assessment is, however, too demanding to be implemented in clinical practice. Objective: To assess the value of convolutional neural networks (CNNs) in the automatic segmentation of infarct volume in follow-up CT images in a large population of patients with acute ischemic stroke. Materials and methods: We included CT images of 1026 patients from a large pooling of patients with acute ischemic stroke. A reference standard for the infarct segmentation was generated by manual delineation. We introduce three CNN models for the segmentati
Occupational Exposure to Endocrine-Disrupting Chemicals and Birth Weight and Length of Gestation: A European Meta-Analysis
BACKGROUND: Women of reproductive age can be exposed to
endocrine-disrupting chemicals (EDCs) at work and exposure to
EDCs in pregnancy may affect fetal growth. OBJECTIVES: We
assessed whether maternal occupational exposure to EDCs during
pregnancy as classified by application of a job exposure matrix
was associated with birth weight, term low birth weight (LBW),
length of gestation, and preterm delivery. METHODS: Using
individual participant data from 133,957 mother-child pairs in
13 European cohorts spanning births from 1994 to 2011, we linked
maternal job titles with exposure to 10 EDC groups as assessed
through a job exposure matrix. For each group, we combined the
two levels of exposure categories (possible and probable) and
compared birth outcomes with the unexposed group (exposure
unlikely). We performed meta-analyses of cohort-specific
estimates. RESULTS: Eleven percent of pregnant women were
classified as exposed to EDCs at work during pregnancy based on
job title. Classification of exposure to one or more EDC group
was associated with an increased risk of term LBW (OR 1.25,
95%CI 1.04, 1.49), as were most specific EDC groups; this
association was consistent across cohorts. Further, the risk
increased with increasing number of EDC groups (OR 2.11 95%CI
1.10, 4.06 for exposure to 4 or more EDC groups). There were few
associations (p < 0.05) with the other outcomes; women
holding job titles classified as exposed to bisphenol A or
brominated flame retardants were at higher risk for longer
length of gestation. CONCLUSION: Results from our large
population-based birth cohort design indicate that employment
during pregnancy in occupations classified as possibly or
probably exposed to EDCs was associated with an increased risk
of term LBW
Plk1 regulates mitotic Aurora A function through βTrCP-dependent degradation of hBora
Polo-like kinase 1 (Plk1) and Aurora A play key roles in centrosome maturation, spindle assembly, and chromosome segregation during cell division. Here we show that the functions of these kinases during early mitosis are coordinated through Bora, a partner of Aurora A first identified in Drosophila. Depletion of human Bora (hBora) results in spindle defects, accompanied by increased spindle recruitment of Aurora A and its partner TPX2. Conversely, hBora overexpression induces mislocalization of Aurora A and monopolar spindle formation, reminiscent of the phenotype seen in Plk1-depleted cells. Indeed, Plk1 regulates hBora. Following Cdk1-dependent recruitment, Plk1 triggers hBora destruction by phosphorylating a recognition site for \documentclass[12pt]{minimal}
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\begin{document}\end{document}. Plk1 depletion or inhibition results in a massive accumulation of hBora, concomitant with displacement of Aurora A from spindle poles and impaired centrosome maturation, but remarkably, co-depletion of hBora partially restores Aurora A localization and bipolar spindle formation. This suggests that Plk1 controls Aurora A localization and function by regulating cellular levels of hBora
Factors related to transmission of and infection with Schistosoma mansoni in a village in the South-eastern Region of Brazil
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