Qualitative data in demography

Qualitative methods and insights from other disciplines are increasingly integrated into demography’s traditionally quantitative toolkit. Whereas this is not problematic for multi-disciplinary research projects difficulties may arise when quantitatively trained demographers diversify to use less familiar data collection tools. We review the scale of this recent trend and the choice of qualitative methods typically employed by demographic researchers. Using insights from a comparative qualitative study undertaken in Zimbabwe and Senegal, we discuss some problems inherent in qualitative data collection and analysis and propose ways in which such data should and should not be used. Focussing in particular on semi-structured in-depth interviews, we discuss issues of representativity, investigate respondents’ silence on specific topics, and the role of interviewer characteristics in influencing the interview subject matter.data collection, in-depth interviews, interviewers, qualitative data, research methods, Senegal, Zimbabwe

Don't cancel the surgery just yet! A case report of positive preoperative pregnancy test due to a soft tissue sarcoma production of ectopic beta human chorionic gonadotropin.

Soft tissue sarcomas are a rare group of mesenchymal malignancies which can range from low to high grade. These tumors have different clinical, radiographic, and histopathological characteristics. Beta human chorionic gonadotropin is a naturally secreted hormone by placental syncytiotrophoblast cells during pregnancy. On very rare occasions, sarcomas can develop the ability to ectopically produce human chorionic gonadotropin. Very few cases exist in the literature of soft tissue sarcomas expressing this hormone. We report the case of a 55-year-old female who presented with a posterior thigh soft tissue sarcoma who on the day of surgical resection was found to have an unusually elevated serum human chorionic gonadotropin. Positive immunohistochemical staining of the resected mass confirmed the sarcoma as the source of the beta human chorionic gonadotropin

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Solving the primitive equations on a spherical geodesic grid: a technical report to a new class of dynamical cores

November 1998.Includes bibliographical references.This report documents the development and testing of a new type of dynamical core. Toe· model uses the invariant form of the primitive equations, solving the vorticity and divergence equations in place of the momentum equation. In the horizontal directions the model is discretized on a geodesic grid which is nearly uniform over the entire globe. In the vertical direction the model can use a variety of coordinate systems, including the generalized sigma coordinate of Suarez et al. (1983) and the Phillips (1957) sigma coordinate. By integrating the vorticity and divergence equations, terms related to gravity wave propagation are isolated and an efficient semi-implicit time stepping scheme is implemented. The model is tested using the idealized forcing proposed by Held and Suarez (1994). Results are presented for a variety of vertical coordinate systems with horizontal resolutions using 2562 polygons (approximately 4.5° x 4.5°) and using 10242 polygons (approximately 2.25° x 2.25° ). The results are compared to standard spectral model simulations truncated at T30 and T63. In terms of averages and variances of state variables, e geodesic grid model results using 2562 polygons are comparable to those of a spectral model truncated at slightly less than TIO, while a simulation with 10242 polygons is comparable to a spectral model simulation truncated at slightly less than T63. In terms of computational efficiency, further development of this geodesic grid model is required. Model timings completed on an SGI Origin 2000 indicate that the geodesic grid model with 10242 polygons is 2.7 times slower than the spectral model truncated at T63. At these resolutions, the MFlop rate of the geodesic grid model is 15% faster than the spectral model, so the differences in model speed are due to differences in the number of floating point operations required per day of simulation. The geodesic grid model is more competitive at higher resolution than at lower resolution, so further optimization and future trends toward higher resolution should benefit the geodesic grid model.Sponsored by the U.S. Department of Energy DE-FG03-98ER62611 and DE-FG03-94ER61929

Factors Influencing Soil Aggregation and Particulate Organic Matter Responses to Bioenergy Crops across a Topographic Gradient

Bioenergy crops have the potential to enhance soil carbon (C) pools fromincreased aggregation and the physical protection of organicmatter; however, our understanding of the variation in these processes over heterogeneous landscapes is limited. In particular, little is known about the relative importance of soil properties and root characteristics for the physical protection of particulate organic matter (POM). We studied short-term (3-year) changes in aggregation and POM-C pools under three cropping systems (switchgrass, a triticale/sorghumdouble crop, continuous corn) replicated across five landscape positions along a topographic gradient in Iowa, USA.We isolated POMassociated with three aggregate fractions (N2mm, 0.25–2mm, and 0.053–0.25mm) to determine the relative influence of ten soil and three root properties. Aggregation increased in all cropping systems andwas greatest under switchgrass; however cropping systemeffectswere not consistent among positions. Total soil organic C stocks did not change, but Cwithin both physically protected (iPOM-C) and unprotected (frPOM) C pools increased. Shifts in iPOM-C were concurrently influenced by soil properties and root traits. Soil texture had the strongest influence (65% relative importance), with finer-textured soils showing greater gains in total iPOM-C, while greater root biomass influenced (35% relative importance) accrual of total iPOM-C. Aggregate fractions varied in their iPOM-C response to soil and root variables, however individual pools similarly showed the importance of soil texture and root biomass and annual root productivity (BNPP). Changes in frPOM-C were strongly correlated with BNPP. Our data suggest that macroaggregate formation drives short-term responses of POM, which are influenced by both soil and root system properties. Crops that maximize root biomass and BNPP will lead to the largest increases in protected soil C stocks. However, C storage rates will vary across landscapes according to soil conditions, with texture as the primary influence

Understanding soil organic matter change: Modeling root and soil interactions across agricultural landscapes

What are some options for enhancing organic content and carbon storage in soils that have been used in intensive row-crop production? The project looked at bioenergy feedstocks and how they might be employed to improve soil properties

Relation between repolarization and refractoriness in the human ventricle: Cycle length dependence and effect of procainamide

The cycle length dependence of the action potential duration and the effective refractory period of the right ventricular endocardium were investigated in 24 patients undergoing electrophysiologic studies for suspected ventricular tachycardia. The action potential duration at 90% repolarization and the effective refractory period at twice diastolic threshold strength were measured at the same catheter site at steady state cycle lengths of 350 to 600 ms. Both measurements decreased linearly with decreasing cycle length, maintaining a parallel relation. When the relation between action potential duration and effective refractory period was expressed as the effective refractory period-action potential duration difference, nearly constant values (range −12 to −15 ms) were obtained at all cycle lengths.To determine whether sodium channel blocking drugs influence the effective refractory period-action potential duration relation in humans, measurements of these two variables were obtained in 15 patients before and during the infusion of procainamide. Procainamide prolonged the action potential duration at each cycle length by a near constant amount over baseline values (p < 0.001). Procainamide also increased the effective refractory period at each cycle length but with a greater incremental increase at the shorter cycle lengths. The rate-dependent increase in the effective refractory period-action potential duration difference became significant at cycle lengths ≤400 ms; at these high rates, the effective refractory period-action potential duration difference became positive (1.6 ms, p < 0.01 compared with baseline).Thus, in the human ventricle, the action potential duration and the effective refractory period have a close relation that remains fixed over a wide range of cycle lengths. The cycle length-dependent increase in the effective refractory period relative to action potential duration induced by procainamide is consistent with use dependency of sodium channel blocking drugs observed in vitro and may be a useful marker for measuring antiarrhythmic drug activity in vivo