2,994 research outputs found
Late stage kinetics for various wicking and spreading problems
The kinetics of spreading of a liquid drop in a wedge or V-shaped groove, in
a network of such grooves, and on a hydrophilic strip, is re-examined. The
length of a droplet of volume Omega spreading in a wedge after a time t is
predicted to scale as Omega^(1/5) * t^(2/5), and the height profile is
predicted to be a parabola in the distance along the wedge. If the droplet is
spreading radially in a sparse network of V-shaped grooves on a surface, the
radius is predicted to scale as Omega^(1/6) * t^(1/3), provided the liquid is
completely contained within the grooves. A number of other results are also
obtained.Comment: 5 pages, 2 figures, RevTeX
Multiple Miniature Avionic Displays
A display screen for displaying multiple sets of information is provided. In one embodiment, an aviation display screen includes a main window and a plurality of miniature windows. The main window is adapted to illustrate one set of information. Each miniature window is adapted to display a set of avionic information. The avionic display is further adapted to toggle a select set of avionic information in one of the miniature windows into the main window
A 200 Year Record of Carbon-13 and Carbon-14 Variations in a Bermuda Coral
A 200 year old brain coral, captured in Bermuda in 1976 was slabbed and x-rayed. Using the annual growth bands sequential, dated samples were taken over the entire growth period of the coral and analyzed for Δ14C, δ13C and δ18O. During the past 80 years atmospheric variations in Δ14C and δ13C due to human effects, such as release of bomb C-14 and dilution of both C-14 and C-13 by fossil fuel burning, are closely tracked by the coral. Prior to 1900 divergences between the coral and tree Δ14C and δ13C can be related to world-wide changes in plant production and possibly oceanic upwelling rates
A bifunctional platinum(II) antitumor agent that forms DNA adducts with affinity for the estrogen receptor
A strategy is described for the re-design of DNA damaging platinum(II) complexes to afford elevated toxicity towards cancer cells expressing the estrogen receptor (ER). Two platinum-based toxicants are described in which a DNA damaging warhead, [Pt(en)Cl[subscript 2]] (en, ethylenediamine), is tethered to either of two functional groups. The first agent, [6-(2-amino-ethylamino)-hexyl]-carbamic acid 2-[6-(7α-estra-1,3,5,(10)-triene)-hexylamino]-ethyl ester platinum(II) dichloride ((Est-en)PtCl[subscript 2]), terminates in a ligand for the ER. The second agent is a control compound lacking the steroid; this compound, N-[6-(2-amino-ethylamino)-hexyl]-benzamide platinum(II) dichloride ((Bz-en)PtCl[subscript 2])), terminates in a benzamide moiety, which lacks affinity for the ER. Using a competitive binding assay, Est-en had 28% relative binding affinity (RBA) for the ER as compared to 17β-estradiol. After covalent binding to a synthetic DNA duplex 16-mer, the compound retained its affinity for the ER; specificity of the binding event was demonstrated by the ability of free 17β-estradiol as a competitor to disrupt the DNA adduct-ER complex. The (Est-en)PtCl[subscript 2] compound showed higher toxicity against the ER positive ovarian cancer cell line CAOV3 than did the control compound. (Est-en)PtCl[subscript 2] was also more toxic to the ER positive breast cancer line, MCF-7, than to an ER negative line, MDA-MB231.National Institutes of Health (U.S.) (Grant CA08661)Life Sciences Research Foundatio
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The impact of teaching in coordinated studies programs on personal, social, and professional development of community college faculty
This study investigated the impact of team-teaching in coordinated-studies programs
(CSPs) on community college faculty in three instructional development domains: personal,
social, and professional. Grounded in a social-constructivist theoretical framework, this
research examined whether development occurs best experientially, in collaborative
communities of knowledgeable peers. CSPs are team-taught interdisciplinary, problem-solving
enterprises involving two or more disciplines. Faculty control content and structure,
and build relationships in subjects while focusing on a central theme, societal issue, or
problem.
Reform initiatives addressing community college instructional quality and
institutional effectiveness have commanded national attention, contributing to an increase in
faculty development programs. In spite of heightened emphasis, there is little evidence of
program effectiveness. Moreover, successful models for improving teaching and learning
are still not fully understood.
Using phenomenologically based interviewing, the study determined how CSPs
impacted development of 10 instructors from two community colleges in Washington State.
Two interviews were conducted, one individually, the other with CSP teams. The index-coding system was an adaptation of a schema designed to assess improved performance in
the three instructional development domains, within the first, second, and third facet. Data
were analyzed using NUD*IST (Non-numerical Unstructured Data Indexing Searching and
Theorizing), a qualitative software program.
Team-teaching in CSPs advanced instructional development and did so more
effectively than does traditional faculty development programs and self-directed
development, participants stated. Additionally, authority in decisions regarding curriculum
and instruction empowered faculty, improving morale and productivity. Another finding
was that planning and instructing a course of study with intellectual comradeship improved
pedagogical practices and produced intellectual insights.
Four important implications for community colleges surfaced in assessment of the
findings : (a) isolation - the condition found in solo teaching - is problematic, impacting
faculty support and feedback, (b) CSPs recapture the scholarship and comradeship
experienced in graduate school programs with discipline peers, (c) instructional
development is a social act improving more effectively through team-teaching with
knowledgeable peers, and (d) faculty experience revitalization and empowerment in CSPs,
alleviating redundancy and boredom from teaching the same courses. The CSP framework
allows for self-direction, spontaneity, and freedom from the barriers and restrictions
experienced in traditional courses
The role of the P2X7 receptor on bone loss in a mouse model of inflammation-mediated osteoporosis
In inflammatory autoimmune diseases, bone loss is frequent. In most cases, secondary osteoporosis is caused by treatment with systemic glucocorticoid. However, the pathogenesis behind the bone loss is presumed multifactorial.
We aimed to elucidate the role of the P2X7 receptor on bone mineral density (BMD), microarchitecture, and bone strength in a standardized mouse model of inflammation-mediated osteoporosis (IMO).
In total 146 mice completed our protocol, 70 wild type (WT) mice and 76 P2X7−/− (knockout, KO). BMD at the femur and spine decreased significantly from baseline to day 20 in the WT IMO mice (p < 0.01). In the WT vehicle, KO vehicle and KO IMO, no significant BMD changes were found.
Bone strength showed a lower mid-shaft max strength (p = 0.038) and also a non-significant trend towards lower strength at the femoral neck of the WT IMO group. Trabecular bone volume fraction (BV/TV) and connectivity density (CD) after 20 days were significantly decreased in the WT IMO group (p = 0.001). In contrast, the WT vehicle and KO vehicle, BV/TV and CD did no change at 20 days. Cortical bone revealed no significant microarchitectural changes after 20 days in the WT IMO group, whereas the total cortical area increased significantly in WT vehicle and KO IMO after 20 days (5.2% and 8.8%, respectively).
In conclusion, the P2X7 receptor KO mice did not respond to inflammation with loss of BMD whereas the WT mice had a significant loss of BMD, bone strength and trabecular microarchitecture, demonstrating a role for the P2X7 receptor in inflammatory bone loss
Market Integration Shape Organic Farmers’ Organisation
Increasing consumption of organic products in globalised food chains will require the involvement of thousands more smallholder farmers in many regions of the world. A study of Egypt, China and Uganda identified the three key factors of property rights regimes, cultural differences and social organisation as determents of the supply chain organization and farmers’ degree of direct integration in the export markets. Patterns are emerging where smallholder farmers are being socially and economically linked to larger farmers who may do some processing before the raw materials are handed over to the contracting company. Where transactions costs are high, local communities may develop and contract out the land directly to exporting companies who farm using employees. Four organisational patterns are identified which each leads to different types of livelihood benefits for the producers; preliminary results indicate that income and a reliable market access is the dominant benefits
Stable Hydrogen Isotope Analysis of Bat Hair as Evidence for Seasonal Molt and Long-Distance Migration
Although hoary bats (Lasiurus cinereus) are presumed to be migratory and capable of long-distance dispersal, traditional marking techniques have failed to provide direct evidence of migratory movements by individuals. We measured the stable hydrogen isotope ratios of bat hair (∂Dh) and determined how these values relate to stable hydrogen isotope ratios of precipitation (∂Dp). Our results indicate that the major assumptions of stable isotope migration studies hold true for hoary bats and that the methodology provides a viable means of determining their migratory movements. We present evidence that a single annual molt occurs in L. cinereus prior to migration and that there is a strong relationship between ∂Dh and ∂Dp during the molt period. This presumably reflects the incorporation of local ∂Dp into newly grown hair. Furthermore, we present evidence that individual hoary bats are capable of traveling distances in excess of 2,000 km and that hair is grown at a wide range of latitudes and elevations. Stable hydrogen isotope analysis offers a promising new tool for the study of bat migration
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Reactive Fluid Flow and Applications to Diagenesis, Mineral Deposits, and Crustal Rocks
The objective is to initiate new: modeling of coupled fluid flow and chemical reactions of geologic environments; experimental and theoretical studies of water-rock reactions; collection and interpretation of stable isotopic and geochemical field data at many spatial scales of systems involving fluid flow and reaction in environments ranging from soils to metamorphic rocks. Theoretical modeling of coupled fluid flow and chemical reactions, involving kinetics, has been employed to understand the differences between equilibrium, steady-state, and non-steady-state behavior of the chemical evolution of open fluid-rock systems. The numerical codes developed in this project treat multi-component, finite-rate reactions combined with advective and dispersive transport in multi-dimensions. The codes incorporate heat, mass, and isotopic transfer in both porous and fractured media. Experimental work has obtained the kinetic rate laws of pertinent silicate-water reactions and the rates of Sr release during chemical weathering. Ab-initio quantum mechanical techniques have been applied to obtain the kinetics and mechanisms of silicate surface reactions and isotopic exchange between water and dissolved species. Geochemical field-based studies were carried out on the Wepawaug metamorphic schist, on the Irish base-metal sediment-hosted ore system, in the Dalradian metamorphic complex in Scotland, and on weathering in the Columbia River flood basalts. The geochemical and isotopic field data, and the experimental and theoretical rate data, were used as constraints on the numerical models and to determine the length and time scales relevant to each of the field areas
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