6 resultados para Difference-in-differences

em Duke University


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Indonesia consistently records higher levels of maternal mortality than other countries in Southeast Asia with its same level of socioeconomic development. I use a quasi-experimental, difference-in-differences approach to understand whether the role of information on the risk of death in childbirth can change women’s reproductive behaviors. In the first two chapters, I use the Maternal Mortality Module from the Demographic and Health Survey (DHS) in Indonesia to examine fertility and reproductive behavior responses to a sister’s death in childbirth. Fertility desires remain relatively unchanged but women take up behaviors in subsequent births that avert the risk of maternal death. In the last chapter, I combine population-representative data from the DHS with a village-level census (PODES) on service availability to understand how a village-level intervention to improve obstetric service use using a birth preparedness and complications readiness (BPCR) approach may improve obstetric service use. In this study, I find that the Desa Siaga intervention in Indonesia improved knowledge of the danger signs of complications among women but not among men relative to villages that did not get the program while controlling for endogenous program placement. More women got antenatal care due to the program but use of a skilled birth attendant and postpartum care did not change as a result of the intervention. Both genders report discussing a blood donor in preparation for delivery.

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This paper contributes to the literature in nancial aid and authoritarian institutions.

For a long time, scholars are debating whether nancial aid is able to facilitate

development and governance. Though abundant evidence is provided, the answer is

still inconclusive. On the other hand, scholars investigating China argue that the

leadership uses various institutions to ensure local ocials' compliance. In this paper,

we nd that the nancial aid does not bring a positive impact and the central

government in China does not have enough monitoring capacity to force local o-

cials to comply. We study a redevelopment program established by Chinese central

government after the 2008 Wenchuan earthquake. By adopting a geographic regression

discontinuity combining with a dierence-in-dierences design, we show that

the redevelopment program does not signicantly develop the disaster area. On the

contrary, the evidence implies that the economy in the disaster area is worse after

receiving the aid. The results imply that local ocials do not follow the central government's

regulations and misuse the aid money for other purposes. In the future, we

expect to further investigate through which mechanism do local ocials undermine

the existing institutions.

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We measured canine teeth from 28 woolly spider monkeys (Brachyteles arachnoides) to assess sexual dimorphism and population differences. The specimens are from the Brazilian states of Bahia, Minas Gerais, Espírito Santo, Rio de Janeiro, and São Paulo. We found strong sexual dimorphism in canine length for individuals belonging to populations south of 22°00′ latitude but no sexual dimorphism in canine length from individuals of populations north of 21°00′ latitude. Canine length did not vary among females of northern and southern populations. However, southern males had significantly longer canines than northern males. This geographical difference in canine morphology, together with the presence or absence of thumbs and published accounts of differences in genetics and social structure between northern and southern populations, suggests that Brachyteles arachnoides may be composed of at least two subspecies, which appear to be separated by the rivers Grande and Paraiba do Sul and the Serra da Mantiqueira. © 1993 Plenum Publishing Corporation.

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BACKGROUND: Ipsilateral hindfoot arthrodesis in combination with total ankle replacement (TAR) may diminish functional outcome and prosthesis survivorship compared to isolated TAR. We compared the outcome of isolated TAR to outcomes of TAR with ipsilateral hindfoot arthrodesis. METHODS: In a consecutive series of 404 primary TARs in 396 patients, 70 patients (17.3%) had a hindfoot fusion before, after, or at the time of TAR; the majority had either an isolated subtalar arthrodesis (n = 43, 62%) or triple arthrodesis (n = 15, 21%). The remaining 334 isolated TARs served as the control group. Mean patient follow-up was 3.2 years (range, 24-72 months). RESULTS: The SF-36 total, AOFAS Hindfoot-Ankle pain subscale, Foot and Ankle Disability Index, and Short Musculoskeletal Function Assessment scores were significantly improved from preoperative measures, with no significant differences between the hindfoot arthrodesis and control groups. The AOFAS Hindfoot-Ankle total, function, and alignment scores were significantly improved for both groups, albeit the control group demonstrated significantly higher scores in all 3 scales. Furthermore, the control group demonstrated a significantly greater improvement in VAS pain score compared to the hindfoot arthrodesis group. Walking speed, sit-to-stand time, and 4-square step test time were significantly improved for both groups at each postoperative time point; however, the hindfoot arthrodesis group completed these tests significantly slower than the control group. There was no significant difference in terms of talar component subsidence between the fusion (2.6 mm) and control groups (2.0 mm). The failure rate in the hindfoot fusion group (10.0%) was significantly higher than that in the control group (2.4%; p < 0.05). CONCLUSION: To our knowledge, this study represents the first series evaluating the clinical outcome of TARs performed with and without hindfoot fusion using implants available in the United States. At follow-up of 3.2 years, TAR performed with ipsilateral hindfoot arthrodesis resulted in significant improvements in pain and functional outcome; in contrast to prior studies, however, overall outcome was inferior to that of isolated TAR. LEVEL OF EVIDENCE: Level II, prospective comparative series.

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In chimpanzees, most females disperse from the community in which they were born to reproduce in a new community, thereby eliminating the risk of inbreeding with close kin. However, across sites, some females breed in their natal community, raising questions about the flexibility of dispersal, the costs and benefits of different strategies and the mitigation of costs associated with dispersal and integration. In this dissertation I address these questions by combining long-term behavioral data and recent field observations on maturing and young adult females in Gombe National Park with an experimental manipulation of relationship formation in captive apes in the Congo.

To assess the risk of inbreeding for females who do and do not disperse, 129 chimpanzees were genotyped and relatedness between each dyad was calculated. Natal females were more closely related to adult community males than were immigrant females. By examining the parentage of 58 surviving offspring, I found that natal females were not more related to the sires of their offspring than were immigrant females, despite three instances of close inbreeding. The sires of all offspring were less related to the mothers than non-sires regardless of the mother’s residence status. These results suggest that chimpanzees are capable of detecting relatedness and that, even when remaining natal, females can largely avoid, though not eliminate, inbreeding.

Next, I examined whether dispersal was associated with energetic, social, physiological and/or reproductive costs by comparing immigrant (n=10) and natal (n=9) females of similar age using 2358 hours of observational data. Natal and immigrant females did not differ in any energetic metric. Immigrant females received aggression from resident females more frequently than natal females. Immigrants spent less time in social grooming and more time self-grooming than natal females. Immigrant females primarily associated with resident males, had more social partners and lacked close social allies. There was no difference in levels of fecal glucocorticoid metabolites in immigrant and natal females. Immigrant females gave birth 2.5 years later than natal females, though the survival of their first offspring did not differ. These results indicate that immigrant females in Gombe National Park do not face energetic deficits upon transfer, but they do enter a hostile social environment and have a delayed first birth.

Next, I examined whether chimpanzees use condition- and phenotype-dependent cues in making dispersal decisions. I examined the effect of social and environmental conditions present at the time females of known age matured (n=25) on the females’ dispersal decisions. Females were more likely to disperse if they had more male maternal relatives and thus, a high risk of inbreeding. Females with a high ranking mother and multiple maternal female kin tended to disperse less frequently, suggesting that a strong female kin network provides benefits to the maturing daughter. Females were also somewhat less likely to disperse when fewer unrelated males were present in the group. Habitat quality and intrasexual competition did not affect dispersal decisions. Using a larger sample of 62 females observed as adults in Gombe, I also detected an effect of phenotypic differences in personality on the female’s dispersal decisions; extraverted, agreeable and open females were less likely to disperse.

Natural observations show that apes use grooming and play as social currency, but no experimental manipulations have been carried out to measure the effects of these behaviors on relationship formation, an essential component of integration. Thirty chimpanzees and 25 bonobos were given a choice between an unfamiliar human who had recently groomed or played with them over one who did not. Both species showed a preference for the human that had interacted with them, though the effect was driven by males. These results support the idea that grooming and play act as social currency in great apes that can rapidly shape social relationships between unfamiliar individuals. Further investigation is needed to elucidate the use of social currency in female apes.

I conclude that dispersal in female chimpanzees is flexible and the balance of costs and benefits varies for each individual. Females likely take into account social cues present at maturity and their own phenotype in choosing a settlement path and are especially sensitive to the presence of maternal male kin. The primary cost associated with philopatry is inbreeding risk and the primary cost associated with dispersal is delay in the age at first birth, presumably resulting from intense social competition. Finally, apes may strategically make use of affiliative behavior in pursuing particular relationships, something that should be useful in the integration process.

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Dancers of all forms often engage in aesthetic yet challenging movements. Their training, choreography, and performances require strength, stamina, flexibility, grace, passion, and emotion. Ballet and Bharatanatyam (an Indian classical dance form) dancers utilize two movements in each of their dance forms that are similar—a half-sitting pose and a full-sitting pose, both requiring external rotation of the legs and bending at the knee joints. The purpose of this study was to examine and compare the biomechanics of joint reaction forces and knee angles in both styles of dance for these particular poses. The study included nine female ballet dancers and seven female Bharatanatyam dancers. Hamstring and gastrocnemius flexibility were measured for each dancer. Knee angles, vertical peak forces, and moments were determined for dancers at the lowest point of their bending positions. Mann-Whitney U tests found significant differences in hamstring flexibility, right gastrocnemius flexibility, and knee angles for the full-sitting poses between ballet and Bharatanatyam dancers. No significant difference was found in the vertical peak forces as a ratio to total body weight and moments between the two styles of dance. Further research can be done to more directly assess a difference in injury risk between the ballet and Bharatanatyam dancers.