Binary Colloidal Alloy Test-5: Aspheres

The Binary Colloidal Alloy Test - 5: Aspheres (BCAT-5-Aspheres) experiment photographs initially randomized colloidal samples (tiny nanoscale spheres suspended in liquid) in microgravity to determine their resulting structure over time. BCAT-5-Aspheres will study the properties of concentrated systems of small particles when they are identical, but not spherical in microgravity.

Get a GRIP on Comprehension

Durkin\u27s research (1978-79) has indicated that much more time is spent testing reading comprehension than teaching it. Consequently, all reading comprehension skills need to be taught by the teacher to the students in the classroom. Since making inferences is a necessary comprehension skill when reading across the curriculum (Gordon, 1985), it also must be taught. However, many children find it difficult to make inferences because they are required not only to derive a conclusion from the facts or premises found in their reading materials, but in many cases, they must go beyond the text to their own knowledge and experiences for information. Thus, prior knowledge which student bring to the text, as well as their sensitivity to the text information, are essential aspects of inferential comprehension

Barbiturate and picrotoxin-sensitive chloride efflux in rat cerebral cortical synaptoneurosomes

AbstractThe effects of various barbiturates and picrotoxin in modifying the efflux of chloride (36Cl−) was studied in a novel subcellular preparation from rat cerebral cortex, the ‘synaptoneurosome’. Dilution of synaptoneurosomes pre-loaded with 36Cl− resulted in rapid efflux of 36Cl− that could be measured as early as 10 s following dilution. In the presence of barbiturates such as pentobarbital and hexobarbital there was a significant increase in 36Cl− efflux which was not observed with the pharmacologically-inactive barbiturate, barbital. The effect of barbiturates in enhancing 36Cl− efflux was also stereospecific [(−)-DMBB > (+)-DMBB] and reversed by picrotoxin. By contrast, picrotoxin alone significantly inhibited 36Cl− efflux. These data demonstrate pharmacologically relevant Cl− transport for the first time in a subcellular brain preparation

Five-year survival after surgical treatment for kidney cancer

BACKGROUND. Kidney cancer's rising incidence is largely attributable to the increased detection of small renal masses. Although surgery rates have paralleled this incidence trend, mortality continues to rise, calling into question the necessity of surgery for all patients with renal masses. Using a population-based cohort, a competing risk analysis was performed to estimate patient survival after surgery for kidney cancer, as a function of patient age and tumor size at diagnosis. METHODS. With data from the Surveillance, Epidemiology, and End Results Program (1983–2002), a cohort was assembled of 26,618 patients with surgically treated, local-regional kidney cancer. Patients were sorted into 20 age-tumor size categories and the numbers of patients that were alive, dead from kidney cancer, and dead from other causes were tabulated. Poisson regression models were fitted to obtain estimates of cancer-specific and competing-cause mortality. RESULTS. Age-specific kidney cancer mortality was stable across all size strata but varied inversely with tumor size. Patients with the smallest tumors enjoyed the lowest cancer-specific mortality (5% for masses ≤4 cm). Competing-cause mortality rose with increasing patient age. The estimated 5-year competing-cause mortality for elderly subjects (≥70 years) was 28.2% (95% confidence interval [CI]: 25.9%–30.8%), irrespective of tumor size. CONCLUSIONS. Despite surgical therapy, competing-cause mortality for patients with renal masses rises with increasing patient age. After 5 years, one-third of elderly patients (≥70 years) will die from other causes, suggesting the need for prospective studies to evaluate the role of active surveillance as an initial therapeutic approach for some small renal masses. Cancer 2007. © 2007 American Cancer Society.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/55991/1/22600_ftp.pd

Explosive diversification following a benthic to pelagic shift in freshwater fishes

BACKGROUND: Interspecific divergence along a benthic to pelagic habitat axis is ubiquitous in freshwater fishes inhabiting lentic environments. In this study, we examined the influence of this habitat axis on the macroevolution of a diverse, lotic radiation using mtDNA and nDNA phylogenies for eastern North America\u27s most species-rich freshwater fish clade, the open posterior myodome (OPM) cyprinids. We used ancestral state reconstruction to identify the earliest benthic to pelagic transition in this group and generated fossil-calibrated estimates of when this shift occurred. This transition could have represented evolution into a novel adaptive zone, and therefore, we tested for a period of accelerated lineage accumulation after this historical habitat shift. RESULTS: Ancestral state reconstructions inferred a similar and concordant region of our mtDNA and nDNA based gene trees as representing the shift from benthic to pelagic habitats in the OPM clade. Two independent tests conducted on each gene tree suggested an increased diversification rate after this inferred habitat transition. Furthermore, lineage through time analyses indicated rapid early cladogenesis in the clade arising after the benthic to pelagic shift. CONCLUSIONS: A burst of diversification followed the earliest benthic to pelagic transition during the radiation of OPM cyprinids in eastern North America. As such, the benthic/pelagic habitat axis has likely influenced the generation of biodiversity across disparate freshwater ecosystems. doi: 10.1186/1471-2148-13-27

Rotational Evolution During Type I X-Ray Bursts

The rotation rates of six weakly-magnetic neutron stars accreting in low-mass X-ray binaries have most likely been measured by Type I X-ray burst observations with RXTE. The nearly coherent oscillations detected during the few seconds of thermonuclear burning are most simply understood as rotational modulation of brightness asymmetries on the neutron star surface. We show that, as suggested by Strohmayer and colleagues, the frequency changes of 1-2 Hz observed during bursts are consistent with angular momentum conservation as the burning shell hydrostatically expands and contracts. We calculate how vertical heat propagation through the radiative outer layers of the atmosphere and convection affect the coherence of the oscillation. We show that the evolution of the rotational profile depends strongly on whether the burning layers are composed of pure helium or mixed hydrogen/helium. Our results help explain the absence (presence) of oscillations from hydrogen-burning (helium-rich) bursts that was found by Muno and collaborators. We investigate angular momentum transport within the burning layers and the recoupling of the burning layers with the star. We show that the Kelvin-Helmholtz instability is quenched by the strong stratification, and that mixing between the burning fuel and underlying ashes by the baroclinic instability does not occur. However, the baroclinic instability may have time to operate within the differentially rotating burning layer, potentially bringing it into rigid rotation.Comment: To appear in The Astrophysical Journal; minor corrections made to tables and figure

How new technology is addressed by researchers in educational studies: approaches from high-performing universities in China and the UK

There is a crisis of expectation in relation to educational technology. This is sometimes interpreted as a failure of academic researchers to disseminate their work to educational practitioners. However, another interpretation dwells on the lack of vision characterising such research. Because teachers often encounter research most intensely during their own pre-service and in-service education, we review academic research here through a snapshot of output from 10 leading university Education departments sampled in the UK and China. Empirical papers with a central interest in new technology were scarce, representing around 10% of the sample. Research was strongly situated in 'classroom' contexts although, as critics have suggested, with limited attention to the wider ecology of those places and with teachers being the focal interest as much as students. An 'outcomes' research orientation was less common than an interest in process. Although this was approached with different methodologies in China and the UK. Discussion addresses the challenge of effective and authoritative dissemination and constraints arising from the political economy of research itself