218 research outputs found
The Shields Family: A Dichotomy of Race in US Society through Two Family Lines
The history of the Shields families of North and South Carolina, beginning with William Bryant Shields Sr. and Moses Shields respectively, offer dichotomous responses to American racial hierarchies over the decades. Generations of race mixing within the Shields family has its roots in the sons of Irish immigrants pursuing relationships with enslaved women. The one-sided nature of the power dynamic in these relationships takes on different dimensions in the lives of the mixed-race children of William Bryant Shields Sr. and the lives of Moses’ son, Henry Wells Shields, Henry’s slave Melvinia Shields, and her children. Both family lines take efforts to repress their black ancestry, one primarily through dilution through marriage and the other through a refusal of formal acknowledgement, which ironically enabled some of their children to flourish in African American society. The permeability of race can be gleaned through these two Shields family lines both in how they went about repressing their ties to enslaved black women and how these culminated in the present-day Shields descendants, Roseanne Cash and Michelle Obama
Wind-Tunnel Investigation of Wings with Ordinary Ailerons and Full-Span External-Airfoil Flaps
Report presents an investigation carried out in the NACA 7- by 10-foot wind tunnel of an NACA 23012 airfoil equipped, first, with a full-span NACA 23012 external-airfoil flap having a chord 0.20 of the main airfoil chord and with a full-span aileron with a chord 0.12 of the main airfoil chord on the trailing edge of the main airfoil and equipped second, with a 0.30-chord full-span NACA 23012 external-airfoil flap and a 0.13-chord full-span aileron. The results are arranged in three groups, the first two of which deal with the airfoil characteristics of the two airfoil-flap combinations and with the internal-control characteristics of the airfoil-flap-aileron combinations. The third group of tests deals with several means for balancing ailerons mounted on a special large-chord NACA 23012 external-airfoil flap. The tests included an ordinary aileron, a curtained-nose balance, a frise balance, and a tab
Pay-to-Bid Auctions
We analyze a new auction format in which bidders pay a fee each time they increase the auction price. Bidding fees are the primary source of revenue for the seller, but produce the same expected revenue as standard auctions. Our model predicts a particular distribution of ending prices, which we test against observed auction data. Our model fits the data well for over three-fourths of routinely auctioned items. The notable exceptions are video game paraphernalia, which show more aggressive bidding and higher expected revenue. By incorporating mild risk-loving preferences in the model, we explain nearly all of the auctions.
Animal Pain Models for Spinal Cord Stimulation
Spinal cord stimulation (SCS) is an electrical neuromodulation technique with proven effectiveness and safety for the treatment of intractable chronic pain in humans. Despite its widespread use, the mechanism of action is not fully understood. Animal models of chronic pain, particularly rodent-based, have been adapted to study the effect of SCS on pain-like behavior, as well as on the electrophysiology and molecular biology of neural tissues. This chapter reviews animal pain models for SCS, emphasizing on findings relevant to advancing our understanding of the mechanism of action of SCS, and highlighting the contribution of the animal model to advance clinical outcomes. The models described include those in which SCS has been coupled to neuropathic pain models in rats and sheep based on peripheral nerve injuries, including the chronic constriction injury (CCI) model and the spared nerve injury model (SNI). Other neuropathic pain models described are the spinal nerve ligation (SNL) for neuropathic pain of segmental origin, as well as the chemotherapy-induced and diabetes-induced peripheral neuropathy models. We also describe the use of SCS with inflammatory pain and ischemic pain models
A parsimonious explanation for intersecting perinatal mortality curves: understanding the effect of plurality and of parity
BACKGROUND: Birth weight- and gestational age-specific perinatal mortality curves intersect when compared across categories of maternal smoking, plurality, race and other factors. No simple explanation exists for this paradoxical observation. METHODS: We used data on all live births, stillbirths and infant deaths in Canada (1991–1997) to compare perinatal mortality rates among singleton and twin births, and among singleton births to nulliparous and parous women. Birth weight- and gestational age-specific perinatal mortality rates were first calculated by dividing the number of perinatal deaths at any given birth weight or gestational age by the number of total births at that birth weight or gestational age (conventional calculation). Gestational age-specific perinatal mortality rates were also calculated using the number of fetuses at risk of perinatal death at any given gestational age. RESULTS: Conventional perinatal mortality rates among twin births were lower than those among singletons at lower birth weights and earlier gestation ages, while the reverse was true at higher birth weights and later gestational ages. When perinatal mortality rates were based on fetuses at risk, however, twin births had consistently higher mortality rates than singletons at all gestational ages. A similar pattern emerged in contrasts of gestational age-specific perinatal mortality among singleton births to nulliparous and parous women. Increases in gestational age-specific rates of growth-restriction with advancing gestational age presaged rising rates of gestational age-specific perinatal mortality in both contrasts. CONCLUSIONS: The proper conceptualization of perinatal risk eliminates the mortality crossover paradox and provides new insights into perinatal health issues
Customized birth weight for gestational age standards: Perinatal mortality patterns are consistent with separate standards for males and females but not for blacks and whites
BACKGROUND: Some currently available birth weight for gestational age standards are customized but others are not. We carried out a study to provide empirical justification for customizing such standards by sex and for whites and blacks in the United States. METHODS: We studied all male and female singleton live births and stillbirths (22 or more weeks of gestation; 500 g birth weight or over) in the United States in 1997 and 1998. White and black singleton live births and stillbirths were also examined. Qualitative congruence between gestational age-specific growth restriction and perinatal mortality rates was used as the criterion for identifying the preferred standard. RESULTS: The fetuses at risk approach showed that males had higher perinatal mortality rates at all gestational ages compared with females. Gestational age-specific growth restriction rates based on a sex-specific standard were qualitatively consistent with gestational age-specific perinatal mortality rates among males and females. However, growth restriction patterns among males and females based on a unisex standard could not be reconciled with perinatal mortality patterns. Use of a single standard for whites and blacks resulted in gestational age-specific growth restriction rates that were qualitatively congruent with patterns of perinatal mortality, while use of separate race-specific standards led to growth restriction patterns that were incompatible with patterns of perinatal mortality. CONCLUSION: Qualitative congruence between growth restriction and perinatal mortality patterns provides an outcome-based justification for sex-specific birth weight for gestational age standards but not for the available race-specific standards for blacks and whites in the United States
An Outcome-based Approach for the Creation of Fetal Growth Standards: Do Singletons and Twins Need Separate Standards?
Contemporary fetal growth standards are created by using theoretical properties (percentiles) of birth weight (for gestational age) distributions. The authors used a clinically relevant, outcome-based methodology to determine if separate fetal growth standards are required for singletons and twins. All singleton and twin livebirths between 36 and 42 weeks’ gestation in the United States (1995–2002) were included, after exclusions for missing information and other factors (n = 17,811,922). A birth weight range was identified, at each gestational age, over which serious neonatal morbidity and neonatal mortality rates were lowest. Among singleton males at 40 weeks, serious neonatal morbidity/mortality rates were lowest between 3,012 g (95% confidence interval (CI): 3,008, 3,018) and 3,978 g (95% CI: 3,976, 3,980). The low end of this optimal birth weight range for females was 37 g (95% CI: 21, 53) less. The low optimal birth weight was 152 g (95% CI: 121, 183) less for twins compared with singletons. No differences were observed in low optimal birth weight by period (1999–2002 vs. 1995–1998), but small differences were observed for maternal education, race, parity, age, and smoking status. Patterns of birth weight-specific serious neonatal morbidity/neonatal mortality support the need for plurality-specific fetal growth standards
Testing for Fictive Learning in Decision-Making Under Uncertainty
We conduct two experiments where subjects make a sequence of binary choices between risky and ambiguous binary lotteries. Risky lotteries are defined as lotteries where the relative frequencies of outcomes are known. Ambiguous lotteries are lotteries where the relative frequencies of outcomes are not known or may not exist. The trials in each experiment are divided into three phases: pre-treatment, treatment and post-treatment. The trials in the pre-treatment and post-treatment phases are the same. As such, the trials before and after the treatment phase are dependent, clustered matched-pairs, that we analyze with the alternating logistic regression (ALR) package in SAS. In both experiments, we reveal to each subject the outcomes of her actual and counterfactual choices in the treatment phase. The treatments differ in the complexity of the random process used to generate the relative frequencies of the payoffs of the ambiguous lotteries. In the first experiment, the probabilities can be inferred from the converging sample averages of the observed actual and counterfactual outcomes of the ambiguous lotteries. In the second experiment the sample averages do not converge. If we define fictive learning in an experiment as statistically significant changes in the responses of subjects before and after the treatment phase of an experiment, then we expect fictive learning in the first experiment, but no fictive learning in the second experiment. The surprising finding in this paper is the presence of fictive learning in the second experiment. We attribute this counterintuitive result to apophenia: “seeing meaningful patterns in meaningless or random data.” A refinement of this result is the inference from a subsequent Chi-squared test, that the effects of fictive learning in the first experiment are significantly different from the effects of fictive learning in the second experiment
What do we know the experiences and outcomes of anti-racist social work education? An empirical case study evidencing contested engagement and transformative learning
In social work education there have been very few attempts to empirically capture and measure how professional training programmes prepare students to work with ‘race’ equality and cultural diversity issues. This paper interrogates the experiences and outcomes of anti-racist social work education and evaluates the pedagogic relevance and practice utility of teaching social work students about ‘race’, racism and anti-racism. The data presented in this paper suggests that it is possible to discover the situated experiences of learning about anti-racism and measure how this teaching can affect and lead to knowledge, skills and attitudinal change. The triangulated mixed methods evidence presented in this paper combines nomothetic and idiographic approaches with quantitative data for a matched pair sample of 36 social work students and uses non-parametric statistical tests to measure at two time intervals (before and after teaching); knowledge, skills and attitudinal change. The paper explores how anti-racist social work education enables students to move from ‘magical consciousness ’, where racism and racial oppression is invisible and thereby left unchallenged and maintained, to more critical and reflexive level of awareness where it is named, challenged and no longer shrouded in a culture of professional denial and silencing
Intranasal fentanyl versus intravenous morphine in the emergency department treatment of severe painful sickle cell crises in children: Study protocol for a randomised controlled trial
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