Maternal Age and Infant Mortality: A Test of the Wilcox-Russell Hypothesis

It has been argued (e.g., the Wilcox-Russell hypothesis) that (low) birth weight is a correlate of adverse birth outcomes but is not on the “causal” pathway to infant mortality. However, the US national policy for reducing infant mortality is to reduce low birth weight. If these theoretical views are correct, lowering the rate of low birth weight may have little effect on infant mortality. In this paper, the authors use the “covariate density defined mixture of logistic regressions” method to formally test the Wilcox-Russell hypothesis that a covariate which influences birth weight, in this case maternal age, can influence infant mortality directly but not indirectly through birth weight. The authors analyze data from 8 populations in New York State (1985–1988). The results indicate that among the populations examined, 1) maternal age significantly influences the birth weight distribution and 2) maternal age also affects infant mortality directly, but 3) the influence of maternal age on the birth weight distribution has little or no effect on infant mortality, because the birth-weight-specific mortality curve shifts accordingly to compensate for changes in the birth weight distribution. These results tend to support the Wilcox-Russell hypothesis for maternal age

Independent nurse medication provision: A mixed method study assessing impact on patients' experience, processes, and costs in sexual health clinics

BACKGROUND: Local services in the United Kingdom National Health Service enable autonomous provision of medication by nurses, supporting individual nurses to gain prescribing qualifications or by introducing local patient group directions. AIM: To compare nurse prescribing and patient group directions about clinic processes, patients' experiences, and costs from the perspectives of providers, nurses, and patients. DESIGN: Mixed methods, comparative case study in five urban sexual health services in the United Kingdom. METHODS: Data were collected from nurse prescribers, patient group direction users and their patients July 2015 to December 2016. Nurse questionnaires explored training (funding and methods). Nurses recorded consultation durations and support from other professionals in clinical diaries. Patient notes were reviewed to explore medication provision, appropriateness and safety; errors were judged by an expert panel. Patients completed satisfaction questionnaires about consultations and information about medications. RESULTS: Twenty-eight nurse prescribers and 67 patient group directions users took part; records of 1682 consultations were reviewed, with 1357 medications prescribed and 98.5% therapeutically appropriate. Most medication decisions were deemed safe (96.0% nurse prescribers, 98.7% patient group directions, Fisher's Exact Test p = .55). Errors were predominantly minor (55.6% nurse prescribers, 62.4% patient group directions) and related to documentation omissions (78.0%); no patients were harmed. Consultation durations and unplanned re-consultations were similar for both groups. Nurse prescribers sought assistance from colleagues less frequently (chi-squared = 46.748, df = 1, p 96%). CONCLUSIONS: Nurse medication provision by both nurse prescribers and patient group direction users is safe and associated with high patient satisfaction; effects on clinic processes and costs are similar. Undertaking the prescribing qualification involves independent study but may bring longer-term career progression to nurses

The Influence of Affect on HPV Vaccine Decision Making in an HPV Vaccine Naïve College Student Population

The HPV vaccine is recommended for all adolescents starting at age 11, but coverage is low, especially in the young adult population. The CDC is prioritizing catch-up vaccination and has expanded recommendations for all young adults to age 26. College students may be ideal targets for HPV vaccine interventions as they typically have on-site clinics that offer prevention services and students are in the position to make decisions about their own healthcare. We examined the risk perceptions of 101 HPV vaccine-naïve college students, both in terms of risk cognition (beliefs about susceptibility to HPV-related cancers and genital warts) and affect (worry and fear regarding HPV-related health outcomes) as they relate to HPV vaccine intentions. Participants completed an online survey, reporting absolute and comparative risk perceptions for HPV-related cancers/genital warts, fear and worry related to getting HPV-related cancer and/or genital warts, desire for positive emotions, affective associations with the HPV vaccine, and intentions to get the HPV vaccine. More fear/worry about vaccination was directly associated with increased vaccine intentions. The perceived risk to intentions relation included an indirect effect via fear/worry. Desire for positive affect strengthened this relation. Positive affective associations with the HPV vaccine were also related to increased vaccine intentions. Given the public health impact of increasing HPV vaccine coverage for young adults, educational strategies framing the HPV vaccine positively while decreasing fear/worry related to negative health outcomes might increase interest in on-campus catch-up vaccination

On testing global optimization algorithms for space trajectory design

In this paper we discuss the procedures to test a global search algorithm applied to a space trajectory design problem. Then, we present some performance indexes that can be used to evaluate the effectiveness of global optimization algorithms. The performance indexes are then compared highlighting the actual significance of each one of them. A number of global optimization algorithms are tested on four typical space trajectory design problems. From the results of the proposed testing procedure we infer for each pair algorithm-problem the relation between the heuristics implemented in the solution algorithm and the main characteristics of the problem under investigation. From this analysis we derive a novel interpretation of some evolutionary heuristics, based on dynamical system theory and we significantly improve the performance of one of the tested algorithms

Area-preserving dynamics of a long slender finger by curvature: a test case for the globally conserved phase ordering

A long and slender finger can serve as a simple ``test bed'' for different phase ordering models. In this work, the globally-conserved, interface-controlled dynamics of a long finger is investigated, analytically and numerically, in two dimensions. An important limit is considered when the finger dynamics are reducible to the area-preserving motion by curvature. A free boundary problem for the finger shape is formulated. An asymptotic perturbation theory is developed that uses the finger aspect ratio as a small parameter. The leading-order approximation is a modification of ``the Mullins finger" (a well-known analytic solution) which width is allowed to slowly vary with time. This time dependence is described, in the leading order, by an exponential law with the characteristic time proportional to the (constant) finger area. The subleading terms of the asymptotic theory are also calculated. Finally, the finger dynamics is investigated numerically, employing the Ginzburg-Landau equation with a global conservation law. The theory is in a very good agreement with the numerical solution.Comment: 8 pages, 4 figures, Latex; corrected typo

Degenerate dispersive equations arising in the study of magma dynamics

An outstanding problem in Earth science is understanding the method of transport of magma in the Earth's mantle. Models for this process, transport in a viscously deformable porous media, give rise to scalar degenerate, dispersive, nonlinear wave equations. We establish a general local well-posedness for a physical class of data (roughly $H^1$) via fixed point methods. The strategy requires positive lower bounds on the solution. This is extended to global existence for a subset of possible nonlinearities by making use of certain conservation laws associated with the equations. Furthermore, we construct a Lyapunov energy functional, which is locally convex about the uniform state, and prove (global in time) nonlinear dynamic stability of the uniform state for any choice of nonlinearity. We compare the dynamics to that of other problems and discuss open questions concerning a larger range of nonlinearities, for which we conjecture global existence.Comment: 27 Pages, 7 figures are not present in this version. See http://www.columbia.edu/~grs2103/ for a PDF with figures. Submitted to Nonlinearit

Paramedic educational program attrition accounts for significant loss of potential EMS workforce

OBJECTIVE: Recent concerns for the strength and stability of the emergency medical services (EMS) workforce have fueled interest in enhancing the entry of EMS clinicians into the workforce. However, the educational challenges associated with workforce entry remain unclear. Our objective was to evaluate the educational pathway of entry into the EMS workforce and to identify factors that lead to the loss of potential EMS clinicians. METHODS: This is a cross-sectional evaluation of all US paramedic educational programs, with enrolled students, in the 2019 Committee on Accreditation of Educational Programs for the EMS Professions annual report survey. This data set includes detailed program characteristics and metrics including program attrition rate (leaving before completion), and certifying exam pass rates. Descriptive statistics were calculated, and multivariable logistic regression analysis was conducted to evaluate the association between high program attrition rates (\u3e30%) and program specific characteristics. RESULTS: In 2019, 640 accredited programs met inclusion with 17,457 students enrolled in paramedic educational programs. Of these, 13,884 students successfully graduated (lost to attrition, 3,573/17,457 [21%]) and 12,002 passed the certifying exam on the third attempt (lost to unable to certify, 1,882/17,457 [11%]). High program attrition rates were associated with longer programs (\u3e12 months), small class sizes (\u3c12 \u3estudents), and regional locations. CONCLUSIONS: Nearly 1 in 3 paramedic students were lost from the potentially available workforce either owing to attrition during the educational program or failure to certify after course completion. Attrition represented the largest loss, providing an avenue for future targeted research and interventions to improve EMS workforce stability