2,656 research outputs found

    A Post-Kantian Antinomy.

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    Growth and Size Distribution of the Brachiopod Terebratalia transversa Sowerby

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    Relatively synchronized samplings of man-made structures of known but varying ages have been used to generate a growth curve for Terebratalia. Modes indicative of the first four or five year classes were recognized, and seem internally consistent with each other. Older year classes were indistinguishable. In the vicinity of Seattle, Washington, this species probably does not survive more than nine to ten years. Growth lines, though conspicuous shell features, are not related to age

    Hair Whorls and Monozygosity

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    Some recent results in aerospace vehicle trajectory optimization techniques

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    Algorithms and computation techniques for solving trajectory optimization problem

    \u3cem\u3eOphiostoma clavigerum\u3c/em\u3e is the Mycangial Fungus of the Jeffrey Pine Beetle, \u3cem\u3eDendroctonus jeffreyi\u3c/em\u3e

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    Dendroctonus jeffreyi and D. ponderosae are sibling species of bark beetles (Coleoptera: Scolyti- dae) with few morphological and molecular genetic differences. The two species are believed to have di- verged relatively recently. Dendroctonus jeffreyi colo- nizes only Pinus jeffreyi, while D. ponderosae colonizes up to thirteen Pinus spp., but not P. jeffreyi. Adult beetles of both D. jeffreyi and D. ponderosae carry sym- biotic fungi in mycangia located on the maxillary car- dines. Dendroctonus ponderosae was known to carry two fungi, Ophiostoma clavigerum and 0. montium, in its mycangia. However, it was not known which fungi might be carried by D. jeffreyi. Fungi were isolated from the mycangia of over 900 D. jeffreyi collected from a large portion of its geographic range. Using morphology, isozyme phenotypes, and growth rates at different temperatures, all isolates from D. jeffreyi mycangia were determined to be 0. clavigerum; 0. montium was never isolated from D. jeffreyi mycangi

    Electrical impedance spectroscopy in relation to seed viability and moisture content in snap bean (Phaseolus vulgaris L.)

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    A method, electrical impedance spectroscopy (EIS), is introduced to study seed viability non-destructively. Snap bean (Phaseolus vulgaris L.) seeds were studied by EIS to determine the most sensitive EIS parameter(s) and the optimal range of moisture content (MC) for separation of viable and non-viable seeds. Hydrated seeds exhibited two impedance arcs in the complex plane at the frequency range from 60 Hz to 8 MHz, and impedance spectra of viable and non-viable seeds differed. The hydrated seeds were best-modelled by an equivalent electrical circuit with two distributed circuit elements in series with a resistor (Voigt model). Moisture content and seed viability had strong effects on the EIS parameters. The most sensitive EIS parameters for detecting the differences between viable and non-viable seeds were the capacitance log(C2), the resistance R2, the resistance ratio R2/R1 and the apex ratio, which all represent specific features of the impedance spectrum. The highest differentiation in the EIS parameters between the viable and non-viable seeds occurred in partially imbibed seeds between MC of 40 and 45% (fresh weight basis

    Recirculating 1-K-Pot for Pulse-Tube Cryostats

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    A paper describes a 1-K-pot that works with a commercial pulse tube cooler for astrophysics instrumentation testbeds that require temperatures <1.7 K. Pumped liquid helium-4 cryostats were commonly used to achieve this temperature. However, liquid helium-4 cryostats are being replaced with cryostats using pulse tube coolers. The closed-cycle 1K-pot system for the pulse tube cooler requires a heat exchanger on the pulse tube, a flow restriction, pump-out line, and pump system that recirculates helium-4. The heat exchanger precools and liquefies helium- 4 gas at the 2.5 to 3.5 K pulse tube cold head. This closed-cycle 1-K-pot system was designed to work with commercially available laboratory pulse tube coolers. It was built using common laboratory equipment such as stainless steel tubing and a mechanical pump. The system is self-contained and requires only common wall power to operate. The lift of 15 mW at 1.1 K and base temperature of 0.97 K are provided continuously. The system can be scaled to higher heat lifts of .30 to 50 mW if desired. Ground-based telescopes could use this innovation to improve the efficiency of existing cry

    Mass Drug Administration and beyond: how can we strengthen health systems to deliver complex interventions to eliminate neglected tropical diseases?

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    Achieving the 2020 goals for Neglected Tropical Diseases (NTDs) requires scale-up of Mass Drug Administration (MDA) which will require long-term commitment of national and global financing partners, strengthening national capacity and, at the community level, systems to monitor and evaluate activities and impact. For some settings and diseases, MDA is not appropriate and alternative interventions are required. Operational research is necessary to identify how existing MDA networks can deliver this more complex range of interventions equitably. The final stages of the different global programmes to eliminate NTDs require eliminating foci of transmission which are likely to persist in complex and remote rural settings. Operational research is required to identify how current tools and practices might be adapted to locate and eliminate these hard-to-reach foci. Chronic disabilities caused by NTDs will persist after transmission of pathogens ceases. Development and delivery of sustainable services to reduce the NTD-related disability is an urgent public health priority. LSTM and its partners are world leaders in developing and delivering interventions to control vector-borne NTDs and malaria, particularly in hard-to-reach settings in Africa. Our experience, partnerships and research capacity allows us to serve as a hub for developing, supporting, monitoring and evaluating global programmes to eliminate NTDs
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