Declining rotation curves in interacting galaxies

A declining rotation curve was recently found for the galaxy NGC 3521 by HI synthesis telescope observations (Casertano and van Gorkom 1991). From a comparison of the shapes of rotation curves for a larger sample of galaxies Casertano and van Gorkom argue that this is due to initial properties during the phase of galaxy formation. In several studies of global properties of galaxies, NGC 3521 was always considered a 'normal' unbarred, non-interacting, isolated spiral. However, we present CCD surface photometry that shows at low surface brightness levels the typical signs of interaction or even merging

Improving breastfeeding in rural Tanzania using Bardach’s Policy Analysis Methodology

Appropriate breastfeeding has the potential to have the broadest impact on childhood survival in children under five years (U5Y) compared to all other preventive interventions. The World Health Organization (WHO) and United Nations International Children’s Emergency Fund (UNICEF) recommend that all facilities providing maternal services and newborn care have a written policy addressing breastfeeding that is routinely disseminated to staff. Shirati hospital, in rural Tanzania, does not have a breastfeeding policy. Bardach’s 8-Fold Pathway for policy analysis methodology (adapted by Collins for health policy) was used to evaluate three promising breastfeeding policies to improve compliance with this recommendation. They include exclusive breastfeeding education, complementary food education, and community health worker (CHW) home visits. Analysis identified exclusive breastfeeding with adjunct complimentary food education as the most compelling policy to increase breastfeeding at Shirati hospital. With improved feeding practices, chronic malnutrition rates are expected to decline in and around Shirati

Monitoring solar-type stars for luminosity variations

Since 1984, researchers have made more than 1500 differential photometric b (471 nm) and y (551 nm) measurements of three dozen solar-like lower main sequence stars whose chromospheric activity was previosly studied by O. C. Wilson. Here, researchers describe their methodology and the statistical tests used to distinguish intrinsic stellar variability from observational and instrument errors. The incidence of detected variability among the program and comparison stars is summarized. Among the 100 plus pairs of stars measured differentially, only a dozen were found that were unusually constant, with peak-to-peak amplitudes of seasonal mean brightness smaller than 0.3 percent (0.003 mag) over a two-to-three-year interval

The Physicist - Philosophers: The Legacy of James Clerk Maxwell and Herrmann von Helmholtz

One of the most effective, and most mysterious, tools of modern theoretical physics is a mathematical method including what is here called “field theory.” The success of this procedure in unraveling the “zoology” of fundamental particles and their behavior is a marvel. The philosophical context of this marvel is the source of endless academic controversy. The core of the method is a blend of mathematics and description created by “physicist-philosophers,” from Maxwell and Helmholtz to Einstein and Schrödinger. This book tries to unravel the mystery, or at least chronicle it.https://digitalcommons.bard.edu/facbooks/1000/thumbnail.jp

Interactions Between Protozoan Prey (\u3ci\u3ePhylum protista\u3c/i\u3e) and Their Mosquito Predators (Order \u3ci\u3eDiptera\u3c/i\u3e, Family \u3ci\u3eCuclicidae\u3c/i\u3e) Prey Size and Predator Behavior Effects

Mosquitoes (Diptera. Culicidae) are insects that are medically important as adults as they vector numerous diseases. Yet, understanding the ecology of the larval stage can lead to surveillance and control of adult populations. Aedes albopictus, Aedes triseriatus, Cu/ex corona/or, and Culex quinquefasciatus are four species of mosquito that co-occur in discarded automobile tires. Mosqui-to larvae feed on microorganisms (including protozoans) and particulate organic matter Most larval feeding experiments. howt:ver, have dealt exclusively with bacteria, fungi , and particulate organic matter Although bactena and fungi are important sources of nitrogen and lipids, they may be 111sufficient sources of carbon, which may be supplied by protozoans. The importance of protozoans to mosquitoes is not fully understood. I investigated the interactions between protozoans and mosquitoes based on predator behavior and size selection. I investigated the effect protozoans had when added with bacteria on mosquito larvae performance compared to bacteria alone. There were no siginificant differences for either species in survival. development time, or adult mass between mosquitoes that were fed protozoans or not. I investigated differences m larval behavior between four species of mosquito larvae. Differences m feeding behaviors were significantly greater between genera than within genera, but Culex corona/or shared similar non-feeding behaviors as the two Aedes species. [ investigated the differences in larval survival and mean instar in the presence of three genera of protozoans (Paramecium, Blepharisma, and Colpidium) that represented two size classes. There were no significant differences in survival or mean instar between the seven prey combinations for either species, and the mosquito larvae did not seem to have a preference for one of the prey combinations over the others. My results show that protozoans do not seem to add any value to mosquito larvae, but protozoans may be more important to mosquitoes than just survival, mass, or development time