A reproductive history of mothers with spina bifida offspring-a new look at old issues

BACKGROUND: Spina bifida is a disorder of the cerebrospinal fluid system associated with failure of neural tube closure in the fetus. Reproductive history studies of mothers with spina bifida offspring have often been conducted shortly after the affected child's birth. In this study, a large group of community-based mothers were studied after most had completed their families. The aims were to present a more comprehensive reproductive history and to test several hypotheses regarding the nature of spina bifida. METHODS: Data from 271 mothers was collected by interview 18.3 mean years after the affected child's birth. Data analysis was by χ-square, Fisher exact test and t test with a p value less than 0.05 considered significant. RESULTS: Females made up 56.5% of affected offspring (probands) and 53.1% of unaffected offspring. The spina bifida and anencephaly recurrence rate was 4.0%. The twinning rate was 8.6/1000 live births. 24.4% of mothers had a history of spontaneous abortion and the rate varied by pregnancy order from 87 to 185/1000 live births. Duration of pregnancies subsequent to probands was shorter for female than male probands. Mean birth weight of probands with high lesions exceeded those with low lesions. A spontaneous abortion preceded female probands more often than males as compared to live births. Affected males with high lesions conceived by white mothers were at greater risk to be spontaneously aborted. Previous inter-gestational interval for mothers with no history of spontaneous abortion was longer for probands than unaffected offspring but not for mothers with a history of spontaneous abortion. CONCLUSION: Overall, and for every major subgroup of these mothers, more affected and unaffected female than male offspring were born. Differences by gender and lesion level among probands and between probands and unaffected offspring were consistent with an etiology of unknown genetic factors, hormonal and/or immune system factors

Teaching and learning in virtual worlds: is it worth the effort?

Educators have been quick to spot the enormous potential afforded by virtual worlds for situated and authentic learning, practising tasks with potentially serious consequences in the real world and for bringing geographically dispersed faculty and students together in the same space (Gee, 2007; Johnson and Levine, 2008). Though this potential has largely been realised, it generally isn’t without cost in terms of lack of institutional buy-in, steep learning curves for all participants, and lack of a sound theoretical framework to support learning activities (Campbell, 2009; Cheal, 2007; Kluge & Riley, 2008). This symposium will explore the affordances and issues associated with teaching and learning in virtual worlds, all the time considering the question: is it worth the effort

Analysis of Plasma Filaments with Fast Visible Imaging in the Mega Ampère Spherical Tokamak

The cross-field transport of particles in the scrape-off layer (SOL) of magnetic fusion devices is dominated by the convection of coherent filamentary plasma structures. In this thesis, we present a new technique for the analysis of filaments in fast visible camera data. The new technique operates by inverting the background subtracted emission in the camera images onto a basis set of uniformly emitting field line images, constructed using information from magnetic equilibrium reconstructions. The output of the inversion is a 2D mapping of emission parametrising the average intensity of field lines in the SOL by the coordinates of their intersection with the mid-plane. Filaments manifest in the inverted emission profile as blobs of raised emission. A filament detection technique has been developed to identify these regions of increased emission and fit them with 2D Gaussians. This yields the positions, widths and amplitudes of the filaments. A tracking algorithm is then applied to calculate the filaments velocities and lifetimes. Data from a synthetic camera diagnostic is used to assess the capabilities and limitations of the new technique and quantify its errors. This exercise shows it can detect ~36% of all filaments in the analysis region, corresponding to ~74% of filaments above the targeted amplitude threshold. This sensitivity is achieved with a true positive detection rate of 98.8%. Standard errors in the radial and toroidal positions of the filaments are estimated to be ~2 mm, while errors in the toroidal and radial widths are around ~3 mm and ~7 mm respectively. The shapes of the probability density functions (PDFs) of the filament parameters are also qualitatively recovered and the effect of filament overlap on filament amplitude measurements is investigated. Valuable insight is gained into effects from the non-orthogonality of the field line basis functions and the resulting spatial dependence of the measurement errors. Finally, the technique is applied to MAST data and compared to Langmuir probe measurements. Good agreement is found between the two diagnostics, including exponential waiting times and symmetrical conditionally averaged waveforms. Measurements of the PDFs of filament properties provide valuable inputs for analytic models of SOL transport and show filament lifetimes to be exponentially distributed. The depth of field of the technique enables measurement of the toroidal filament spacing, with results supporting the assertion that filaments are generated uniformly and independently, and are thus described by Poisson statistics underpinning several analytic models

An assessment of the screening method to evaluate vaccine effectiveness: the case of 7-valent pneumococcal conjugate vaccine in the United States.

The screening method, which employs readily available data, is an inexpensive and quick means of estimating vaccine effectiveness (VE). We compared estimates of effectiveness of heptavalent pneumococcal conjugate vaccine (PCV7) against invasive pneumococcal disease (IPD) using the screening and case-control methods. Cases were children aged 19-35 months with pneumococcus isolated from normally sterile sites residing in Active Bacterial Core surveillance areas in the United States. Case-control VE was estimated for 2001-2004 by comparing the odds of vaccination among cases and community controls. Screening-method VE for 2001-2009 was estimated by comparing the proportion of cases vaccinated to National Immunization Survey-derived coverage among the general population. To evaluate the plausibility of screening-method VE findings, we estimated attack rates among vaccinated and unvaccinated persons. We identified 1,154 children with IPD. Annual population PCV7 coverage with ≥1 dose increased from 38% to 97%. Case-control VE for ≥1 dose was estimated as 75% against all-serotype IPD (annual range: 35-83%) and 91% for PCV7-type IPD (annual range: 65-100%). By the screening method, the overall VE was 86% for ≥1 dose (annual range: -240-70%) against all-serotype IPD and 94% (annual range: 62-97%) against PCV7-type IPD. As cases of PCV7-type IPD declined during 2001-2005, estimated attack rates for all-serotype IPD among vaccinated and unvaccinated individuals became less consistent than what would be expected with the estimated effectiveness of PCV7. The screening method yields estimates of VE that are highly dependent on the time period during which it is used and the choice of outcome. The method should be used cautiously to evaluate VE of PCVs

Penicillin Use in Meningococcal Disease Management: Active Bacterial Core Surveillance Sites, 2009.

In 2009, in the Active Bacterial Core surveillance sites, penicillin was not commonly used to treat meningococcal disease. This is likely because of inconsistent availability of antimicrobial susceptibility testing and ease of use of third-generation cephalosporins. Consideration of current practices may inform future meningococcal disease management guidelines

Meningococcal Disease in Patients With Human Immunodeficiency Virus Infection: A Review of Cases Reported Through Active Surveillance in the United States, 2000-2008.

BackgroundAlthough human immunodeficiency virus (HIV) infection is an established risk factor for several bacterial infections, the association between HIV infection and meningococcal disease remains unclear.MethodsExpanded chart reviews were completed on persons with meningococcal disease and HIV infection reported from 2000 through 2008 from 9 US sites participating in an active population-based surveillance system for meningococcal disease. The incidence of meningococcal disease among patients meeting Centers for Disease Control and Prevention acquired immune deficiency syndrome (AIDS) surveillance criteria was estimated using data from the National HIV Surveillance System for the participating sites.ResultsThirty-three cases of meningococcal disease in individuals with HIV infection were reported from participating sites, representing 2.0% of all reported meningococcal disease cases. Most (75.8%) persons with HIV infection were adult males aged 25 to 64 years old. Among all meningococcal disease cases aged 25 to 64 years old, case fatality ratios were similar among HIV-infected and HIV-uninfected persons (13.3% vs 10.6%; P = .6). The cumulative, mean incidence of meningococcal disease among patients aged 25 to 64 years old with HIV infection ever classified as AIDS was 3.5 cases per 100000 person years (95% confidence interval [CI], 2.1-5.6), compared with 0.3 cases per 100000 person years (95% CI, 0.3-0.3) for persons of the same age group not reported to have AIDS (relative risk = 12.9; 95% CI, 7.9-20.9).ConclusionsIndividuals with HIV infection meeting the AIDS surveillance case definition have a higher incidence of meningococcal disease compared with the general adult population

The Northeast Pacific GLOBEC Program: Coastal Gulf of Alaska

(First Paragraph) The Gulf of Alaska (GOA) continental shelf encompasses approximately 370,000 km2, or about 13% of the U.S. continental shell and supports a rich and diverse marine ecosystem including some of the largest commercial fisheries in the U.S. Exclusive Economic Zone. Of particular economic importance is the salmon fishery, which was worth on the order of $170 million (landed value) in 2000 accrued from a catch of over 100 million fish. However, there is considerable variability on both interannual and longer time scales in harvest and recruitment success to this and other GOA fisheries. Of recent interest are compelling indications that abundances of salmon, other fish species, and zooplankton vary on decadal scales in association with North Pacific basin-scale climate changes (Beamish, 1995; Mantua et al., 1997; Roemmich and McGowan, 1995; Brodeur et al., 1996; Francis et al., 1998; Anderson and Piatt, 1999; Hollowed et al., 2001)