7,127 research outputs found

    On the Intracluster Medium in Cooling Flow & Non-Cooling Flow Clusters

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    Recent X-ray observations have highlighted clusters that lack entropy cores. At first glance, these results appear to invalidate the preheated ICM models. We show that a self-consistent preheating model, which factors in the effects of radiative cooling, is in excellent agreement with the observations. Moreover, the model naturally explains the intrinsic scatter in the L-T relation, with ``cooling flow'' and ``non-cooling flow'' systems corresponding to mildly and strongly preheated systems, respectively. We discuss why preheating ought to be favoured over merging as a mechanism for the origin of ``non-cooling flow'' clusters.Comment: 4 pages, to appear in the proceedings of the "Multiwavelength Cosmology" Conference held in Mykonos, Greece, June 2003, ed. M. Plionis (Kluwer

    E-democracy: exploring the current stage of e-government

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    Governments around the world have been pressured to implement e-Government programs in order to improve the government-citizen dialogue. The authors of this article review prior literature on such efforts to find if they lead to increased democratic participation ("e-Democracy") for the affected citizens, with a focus on the key concepts of transparency, openness, and engagement. The authors find that such efforts are a starting point toward e-Democracy, but the journey is far from complete

    Improving the availability of biopesticides : an interdisciplinary research project

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    There is a need for new, biologically-based crop protection products to serve as alternatives to or to complement synthetic chemical pesticides. An interdisciplinary research team from the natural and social sciences considered whether regulatory barriers were preventing more biopesticides reaching the market. The research coincided with a realisation by policy makers that more needed to be done to facilitate biopesticide registration, exemplified by the UK's Biopesticides Scheme. However, important differences remain between the UK and other countries such as the USA. Changes in regulatory arrangements need careful handling. The scientific work undertaken in the project provided a better understanding of the population biology of microbial control agents. Interdisciplinary work permitted a contribution to the policy debate

    Ant-Plant Relationships in a Re-Created Tallgrass Prairie

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    Relationships between the distributions of nesting ants and flora were investigated in a re-created tallgrass prairie located in northeastern Illinois. One-third of 167 randomly selected 1m2 quadrats in the prairie contained ant nests. Basal coverage of ground by tall grass shoots was greater in quadrats having ant nests than in those lacking ant nests. In addition, clumps of big bluestem (Andropogon gerardii) that were inhabited by the ant, Acanthomyops clavigera, had higher median rank densities than adjacent clumps lacking nests. The clumps also showed a negative correlation between big bluestem shoots/ cm2 and area occupied by the clump at ground level. These significant findings relating to the distribution of nesting ants and tall grasses indicate ants have ecologic importance in re-created prairie that warrants greater scrutiny among restoration scientists

    Electrodeposition in capillaries: bottom-up micro- and nanopatterning of functional materials on conductive substrates

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    A cost-effective and versatile methodology for bottom-up patterned growth of inorganic and metallic materials on the micro- and nanoscale is presented. Pulsed electrodeposition was employed to deposit arbitrary patterns of Ni, ZnO, and FeO(OH) of high quality, with lateral feature sizes down to 200–290 nm. The pattern was defined by an oxygen plasma-treated patterned PDMS mold in conformal contact with a conducting substrate and immersed in an electrolyte solution, so that the solid phases were deposited from the solution in the channels of the patterned mold. It is important that the distance between the entrance of the channels, and the location where deposition is needed, is kept limited. The as-formed patterns were characterized by high resolution scanning electron microscope, energy-dispersive X-ray analysis, atomic force microscopy, and X-ray diffraction

    Native Science in Practice: Cases for Broadening Understanding and Engagement of Science in Education as a Plea for Future Generations

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    We make a departure from the U.S.’s traditional “science education” in recognition of several stark realities—from the genocidal practices that have eliminated so many indigenous populations in the U.S. to the problems our planet faces, such dire environmental degradation. We are faced daily with a dissonance of knowing our planet needs our respect and care while at the same time bearing witness to “modern” lifestyles based in property rights and individualism. We engage Native science—which encapsulates all of Western science and expands upon it by including the spiritual and emotional realms as well as the physical and mental dimensions of human existence. In this article, we review several academic programs that have successfully incorporated Native science in indigenous communities by integrating concepts of Native science in the curricula. We argue implementation of Native science approaches to education for all should be considered seriously as part of the larger conversations in science education and curricula toward healing a wounded planet and deeper inclusion of multiple voices in determining trajectories of the practice of science

    The enhancement of the aqueous solubility of ritonavir via formulation of a drug-phospholipid complex

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    Objective: To evaluate the enhancement of aqueous solubility of a poorly water soluble drug ritonavir by forming its complex with a phospholipid (Phospholipon®90H)
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