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1.
Policies increasing healthcare availability might decrease the cost of delaying accessing of care, leading to potential negative consequences if patients delay treatment. We analyze a policy designed to increase access to kidney transplantation through the use of time since dialysis inception to prioritize patients for transplant, which was piloted at 26 of the 271 kidney transplant centers in the United States in 2006 and 2007. We model the patient’s optimization problem comparing the benefits and costs of early waitlisting and predict that the policy change will lead to delayed waitlisting. To empirically test this prediction, we use difference-in-differences fixed effects panel regression techniques to analyze data on patients who began dialysis between 1/1/2000 and 12/31/2009. The results support the model’s prediction; patients on dialysis who waitlist for kidney transplantation increase pre-waitlist dialysis duration by 11.6 percent or approximately 76 days from a pre-policy mean of 652 days (SD = 654). With regard to waitlist outcomes, the policy is associated with a 4.5 percentage point decrease in the probability of receiving a deceased donor transplant, somewhat offset by a 3.0 percentage point increase in the probability of receiving a live donor transplant. On the extensive margin, patients on dialysis decrease their likelihood of ever waitlisting by 1.5 percentage points. We find an increase in pre-waitlist dialysis time and a decrease in the likelihood of waitlisting at all, especially among populations likely to have experienced increased access to transplantation through the policy change: patients self-identifying as Black or Hispanic rather than Non-Hispanic White, and patients without private insurance. These results suggest that some individuals may not benefit if their access to care increases, if the increase in access sufficiently decreases the penalty of delaying accessing of care.  相似文献   

2.
Data from the District Level Household Survey (2002) conducted by the Reproductive and Child Health Project in India has been used to examine the impact of utilization of antenatal care services on improvement in maternal health in rural areas of Uttar Pradesh, India. Multilevel analysis shows that after controlling for other socioeconomic and demographic factors, utilization of antenatal care services may lead to the utilization of other maternal health related services such as institutional delivery, delivery assisted by trained professionals, seeking advice for pregnancy complications, and seeking advice for post-delivery complications. There is strong clustering of utilization of services within the primary sampling units (i.e. villages) and districts.  相似文献   

3.
This paper examines the causal impact of retirement on preventive care use by focusing on breast cancer screening. It contributes to a better understanding of the puzzling results in the literature reporting mixed effects on health care consumption at retirement. We use five waves of data from the Eurobarometer surveys conducted between 1996 and 2006, covering 25 different European countries. We address the endogeneity of retirement by using age thresholds for pension eligibility as instrumental variables in a bivariate probit model. We find that retirement reduces mammography use and other secondary preventive care use. Our results suggest that health status, income, and knowledge on cancer prevention and treatment contribute little to our understanding of the effects of retirement. Instead, our evidence suggests important effect heterogeneity based on the generosity of the social health insurance system and organized screening programs.  相似文献   

4.
We examine the nutritional status of a cohort of poor Ethiopian children and their patterns of catch-up growth in height-for-age between three key development stages: age one, five and eight. We use ordinary least squares (within community) and instrumental variables analysis. During the earliest period, we find that nutritional catch-up patterns vary substantially across socioeconomic groups: average catch-up growth in height-for-age is almost perfect among children in relatively better-off households, while among the poorer children, relative height is more persistent. Between five and eight years of age, however, we find near-perfect persistence and no evidence of heterogeneity in catch-up growth. Our findings suggest that household wealth, and in particular access to services, can lead to substantial catch-up growth early on in life. However, for our sample, the window of opportunity to catch up appears to close as early as the age of five.  相似文献   

5.

Background

Poverty and blindness are believed to be intimately linked, but empirical data supporting this purported relationship are sparse. The objective of this study is to assess whether there is a reduction in poverty after cataract surgery among visually impaired cases.

Methodology/Principal Findings

A multi-centre intervention study was conducted in three countries (Kenya, Philippines, Bangladesh). Poverty data (household per capita expenditure – PCE, asset ownership and self-rated wealth) were collected from cases aged ≥50 years who were visually impaired due to cataract (visual acuity<6/24 in the better eye) and age-sex matched controls with normal vision. Cases were offered free/subsidised cataract surgery. Approximately one year later participants were re-interviewed about poverty. 466 cases and 436 controls were examined at both baseline and follow-up (Follow up rate: 78% for cases, 81% for controls), of which 263 cases had undergone cataract surgery (“operated cases”). At baseline, operated cases were poorer compared to controls in terms of PCE (Kenya: $22 versus £35 p = 0.02, Bangladesh: $16 vs $24 p = 0.004, Philippines: $24 vs 32 p = 0.0007), assets and self-rated wealth. By follow-up PCE had increased significantly among operated cases in each of the three settings to the level of controls (Kenya: $30 versus £36 p = 0.49, Bangladesh: $23 vs $23 p = 0.20, Philippines: $45 vs $36 p = 0.68). There were smaller increases in self-rated wealth and no changes in assets. Changes in PCE were apparent in different socio-demographic and ocular groups. The largest PCE increases were apparent among the cases that were poorest at baseline.

Conclusions/Significance

This study showed that cataract surgery can contribute to poverty alleviation, particularly among the most vulnerable members of society. This study highlights the need for increased provision of cataract surgery to poor people and shows that a focus on blindness may help to alleviate poverty and achieve the Millennium Development Goals.  相似文献   

6.
It has been suggested that bearing sons increases long-term mortality in women, because sons may be more physiologically demanding to produce than daughters. In this historical cohort study in rural Bangladesh, no association between the number of sons born and mortality was seen in women in the unadjusted analyses. However, a significant reduction in mortality with the number of surviving sons was seen. In addition, after adjusting for the number of surviving sons, there was evidence of increasing mortality with the number of sons born, in women. In men, mortality also depended strongly on the number of surviving sons, but not on the number born. These data provide support for negative long-term costs of bearing sons in mothers in rural Bangladesh, and suggest that there are context-specific factors that mask the true effects of sons in some populations.  相似文献   

7.
  • 1.1. Response latencies, denned as the time between a d.c. electric shock and initiation of a fast-start (startle response) were measured for eight species of teleosts.
  • 2.2. Fast-start response latencies varied from 10 to 36 cm. Highest values were found for individuals of two solitary species, Etheostoma caeruleum and Cottus cognatus. Lowest values were found for Esox and Salwo gairdneri.
  • 3.3. Schooling in Perca flavescens, Lepomis macrochirus and Pimephales promelas significantly reduced fast-start response latencies by 7–16 msec. A 4 msec. reduction for Notropis cornutus was not significant.
  • 4.4. No reduction in fast-start response latency was found for Pimephales promelas given the illusion of a school or for individuals greater than 15 cm from a school.
  • 5.5. The observed variation in fast-start response latency would favour attack success of predators and escape success for schooled, but not solitary, presumptive prey.
  相似文献   

8.
The present study aimed to analyze income-related inequality in tobacco consumption in Brazil using data from the National Health Survey at two points in time (2013 and 2019). This study contributes to the growing literature analyzing socioeconomic inequalities in tobacco use by investigating income-related inequalities in the consumption of different tobacco products in Brazil. The inequality measure is the concentration index with an Erreygers correction (EI), and the analysis of its decomposition allows the identification of the factors that determine such inequality. There is inequality in smoking concentrated in the poorest persons, and this pattern also occurs for manufactured cigarettes and roll-your-own cigarettes (RYO), while inequality in smoking cessation is concentrated among the wealthiest. Smoking inequalities were greater in men, older age groups, and RYO. In terms of evolution, the overall results indicated a small decline in smoking inequality. For the decomposition analysis, the results show that the main factors that affect tobacco inequality in terms of concentration in the poorest are education, income, and having private health insurance. The region variable, by contrast, has a positive contribution, since the wealthiest regions have individuals who are more likely to smoke. These results have important implications that serve as a basis for formulating public health policies. For example, greater inequalities for men and older individuals can be targeted by public policies with a special focus on these cases.  相似文献   

9.
10.
Because cross-species evidence suggests that high testosterone (T) may interfere with paternal investment, the relationships between men''s transition to parenting and changes in their T are of growing interest. Studies of human males suggest that fathers who provide childcare often have lower T than uninvolved fathers, but no studies to date have evaluated how nighttime sleep proximity between fathers and their offspring may affect T. Using data collected in 2005 and 2009 from a sample of men (n = 362; age 26.0 ± 0.3 years in 2009) residing in metropolitan Cebu, Philippines, we evaluated fathers'' T based on whether they slept on the same surface as their children (same surface cosleepers), slept on a different surface but in the same room (roomsharers), or slept separately from their children (solitary sleepers). A large majority (92%) of fathers in this sample reported practicing same surface cosleeping. Compared to fathers who slept solitarily, same surface cosleeping fathers had significantly lower evening (PM) T and also showed a greater diurnal decline in T from waking to evening (both p<0.05). Among men who were not fathers at baseline (2005), fathers who were cosleepers at follow-up (2009) experienced a significantly greater longitudinal decline in PM T over the 4.5-year study period (p<0.01) compared to solitary sleeping fathers. Among these same men, baseline T did not predict fathers'' sleeping arrangements at follow-up (p>0.2). These results are consistent with previous findings indicating that daytime father-child interaction contributes to lower T among fathers. Our findings specifically suggest that close sleep proximity between fathers and their offspring results in greater longitudinal decreases in T as men transition to fatherhood and lower PM T overall compared to solitary sleeping fathers.  相似文献   

11.
As a result of reduced intraspecific competition, genetically diverse populations may have higher relative fitness than genetically uniform populations. To test this hypothesis, we compared polyclonal (i.e., genetically diverse) versus monoclonal (i.e., composed of a single clonal genotype) experimental populations of the rotifer Brachionus plicatilis (Müller, 1786) growing separately and in competition. We estimated the following fitness components: intrinsic growth rate; carrying capacity; proportion of sexual females; diapausing egg production per sexual female and total egg production. Polyclonal populations showed similar dynamics to monoclonal populations and no statistical difference between their fitness components was detected. Therefore, results do not support the hypothesis that genetically diverse populations reduce competition through diversification in resource use. Instead, results suggest that B. plicatilis is a generalist consumer whose polyphagy does not depend on genetic differences, but on the broad diet of each genotype. However, clones showed significant differences in almost all fitness components demonstrating among-clone variation in life-history traits. We found a trade-off between sexual ratio and carrying capacity, highlighting the cost of sex in cyclical parthenogenetic rotifers. We discuss the mechanisms that could maintain the observed among-clone genetic variation in natural populations, and speculate on results implication for sex maintenance in rotifers.  相似文献   

12.
Skimming flow was induced in a field flow-through flume with model and live horse mussels as roughness elements. A growth experiment was conducted in the flume with locally available seawater and natural seston. Horse mussel population growth was compared in turbulent isolated element (control) and skimming flow (treatment) and with regulated natural seston levels, indicated by C = bulk flow seston concentration, C1 = seston concentration in the benthic boundary layer, near the inhalant, which just meets the maintenance ration of the mussel population. We were able to control the bulk seston within the range: 1.2 to 5 times of C1 during the growth experiment. No significant difference between control and skimming flow treatments was found in: tissue growth, RNA-DNA ratios, or condition factor. Extrapolating from the experimental results we predict that under minimum growth enhancing seston concentrations at a high horse mussel density (71 m2), skimming flow does not reduce population growth.  相似文献   

13.
Does encouragement help address gender imbalances in technical fields? We present the results of one of the first and largest randomized controlled trials on the topic. Using an applied statistics conference in the social sciences as our context, we randomly assigned half of a pool of 3,945 graduate students to receive two personalized emails encouraging them to apply (n = 1,976) and the other half to receive nothing (n = 1,969). We find a robust, positive effect associated with this simple intervention and suggestive evidence that women responded more strongly than men. However, we find that women’s conference acceptance rates are higher within the control group than in the treated group. This is not the case for men. The reason appears to be that female applicants in the treated group solicited supporting letters at lower rates. Our findings therefore suggest that “low dose” interventions may promote diversity in STEM fields but may also have the potential to expose underlying disparities when used alone or in a non-targeted way.  相似文献   

14.
15.

Background  

Autogenous vein grafting is widely used in regular bypassing procedures. Due to its mismatch with the host artery in both mechanical property and geometry, the graft often over expands under high arterial blood pressure and forms a step-depth where eddy flow develops, thus causing restenosis, fibrous graft wall, etc. External stents, such as sheaths being used to cuff the graft, have been introduced to eliminate these mismatches and increase the patency. Although histological and immunochemical studies have shown some positive effects of the external stent, the mechanical mismatch under the protection of an external stent remains poorly analyzed.  相似文献   

16.
17.
Many organisms respond to the heterogeneity of abiotic environmental conditions by plastic modifications of their phenotypes (acclimation or acclimatization). Despite considerable research efforts in this area, the beneficial (adaptive) effect of acclimation or acclimatization is still debated. We examined whether the development of newt larvae (Ichthyosaura alpestris) under different natural light and thermal conditions subsequently altered their susceptibility to predation in sun‐exposed versus shaded tanks in nature. During predation trials in various light and temperature conditions, newt larvae that developed in sun‐exposed warmer tanks consistently suffered from higher predation by dragonfly nymphs (Aeshna cyanea) compared to larvae from shaded or colder tanks. We conclude that higher sun exposure during embryonic and larval development negatively affects antipredator performance even in sun‐exposed tanks: this result is inconsistent with the beneficial acclimation hypothesis. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ●● , ●●–●●.  相似文献   

18.
The theory of fluctuating resource availability proposes that the susceptibility of a plant community to invasion by new species (i.e., invasibility) depends upon conditions of intermittent resource enrichment coinciding with the presence of invading propagules. We compared the response of a rapidly invading forb (Hieracium pilosella L.) between different experimental treatments in a short tussock grassland in New Zealand, over 6–12 years, to determine whether the theory explains differences in invasibility. The theory predicts that environments subject to periodic resource enrichment will be more invasible than those with more stable resource-supply rates. In our study, H. pilosella did not increase more rapidly in treatments subject to periodic resource pulses (fertiliser and water) than in those with more stable resource supplies. Also contrary to the predictions of the theory, the rate of invasion of H. pilosella did not increase following an increase in the rate of supply of water or nutrient resources, or following treatments that temporarily reduced resource uptake in the community, including grazing. H. pilosella did not increase immediately following abrupt increases in water and nutrient supply and removal of the dominant grass species with herbicide, as predicted by the theory, although temporary increases in resident exotic guilds indicated that the intensity of competition for resources was reduced. Neither H. pilosella nor resident exotic guilds showed increased cover growth rates following resumed grazing. The rate of invasion by H. pilosella was not correlated with species richness, a result consistent with one of the predictions of the theory. Therefore, short-lived events that temporarily reduced or suspended competition did not appear to determine the invasion success of this particular species in this region. In New Zealands perennial short tussock grasslands, the characteristics of the resident plant community may be more critical than resource fluctuations in determining invasion success of H. pilosella. Invasion of H. pilosella may be most successfully controlled here by promoting a successional physiognomic shift to a taller, shrub-and-tussock-dominated canopy that competitively excludes low-growing forbs.  相似文献   

19.

Background

There is evidence that household point-of-use (POU) water treatment products can reduce the enormous burden of water-borne illness. Nevertheless, adoption among the global poor is very low, and little evidence exists on why.

Methods

We gave 600 households in poor communities in Dhaka, Bangladesh randomly-ordered two-month free trials of four water treatment products: dilute liquid chlorine (sodium hypochlorite solution, marketed locally as Water Guard), sodium dichloroisocyanurate tablets (branded as Aquatabs), a combined flocculant-disinfectant powdered mixture (the PUR Purifier of Water), and a silver-coated ceramic siphon filter. Consumers also received education on the dangers of untreated drinking water. We measured which products consumers used with self-reports, observation (for the filter), and chlorine tests (for the other products). We also measured drinking water''s contamination with E. coli (compared to 200 control households).

Findings

Households reported highest usage of the filter, although no product had even 30% usage. E. coli concentrations in stored drinking water were generally lowest when households had Water Guard. Households that self-reported product usage had large reductions in E. coli concentrations with any product as compared to controls.

Conclusion

Traditional arguments for the low adoption of POU products focus on affordability, consumers'' lack of information about germs and the dangers of unsafe water, and specific products not meshing with a household''s preferences. In this study we provided free trials, repeated informational messages explaining the dangers of untreated water, and a variety of product designs. The low usage of all products despite such efforts makes clear that important barriers exist beyond cost, information, and variation among these four product designs. Without a better understanding of the choices and aspirations of the target end-users, household-based water treatment is unlikely to reduce morbidity and mortality substantially in urban Bangladesh and similar populations.  相似文献   

20.
We aimed to predict how hard subjects work for financial rewards from their general trait and state reward-motivation. We specifically asked 1) whether individuals high in general trait “reward responsiveness” work harder 2) whether task-irrelevant cues can make people work harder, by increasing general motivation. Each trial of our task contained a 1 second earning interval in which male subjects earned money for each button press. This was preceded by one of three predictive cues: an erotic picture of a woman, a man, or a geometric figure. We found that individuals high in trait “reward responsiveness” worked harder and earned more, irrespective of the predictive cue. Because female predictive cues are more rewarding, we expected them to increase general motivation in our male subjects and invigorate work, but found a more complex pattern.  相似文献   

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