873 research outputs found
Mineralogical petrochemical and geochemical features of near ore metasomatism in the gold ore deposit "Verkhne-Sakukanskoye" (Northern Transbaikal Region)
Discussion in comparative aspect of the nature of geochemical fields in the mesothermal gold deposits formed in blacks and a crystal substratum is continued. The relation of near vein metasomatic and geochemical auras for a case of intervein spaces of low gold-bearing quartz veins is shown on the example of the deposit «Verkhne-Sakukanskoye» of Northern Transbaikal Region located in southwest early Proterozoic frame of the Chara ledge of the Archean base - the western fragment of the Aldan board. In the first part of the article the geological structure of the deposit, mineral structure of ores are considered. On the basis of studying of mineral composition and structure of rocks with attraction of original chemical silicate analyses and petrochemical calculations the enclosing ore containing bodies of plutonic rocks of the early Proterozoic Kodarsky complex are diagnosed as hornblende - biotite quartz diorite and quartz monzonite. In the second part of the article for the first time a mineralogical - petrochemical zonation of near vein metasomatic auras is described, their belonging to a beresite metasomatic formation, and belonging of the deposit to the gold subformation of a gold - uranium - polymetallic beresite ore formation is proved. The geochemical materials revealing distribution on near Clarke levels of contents of ore genous elements (Au, Ag, Hg, etc.) in an intervein space is given, genetic connection of near vein geochemical auras with near vein metasomatic ones in frames of mesotermal ore-forming process of late Paleozoic epoch is substantiated. The obtained results are consistent with conclusions about structure and conditions of formation of the geochemical fields, made earlier in others mesothermal gold deposits of blacks and not slate types
Extension of the Measurement Capabilities of the Quadrupole Resonator
The Quadrupole Resonator, designed to measure the surface resistance of
superconducting samples at 400 MHz has been refurbished. The accuracy of its
RF-DC compensation measurement technique is tested by an independent method. It
is shown that the device enables also measurements at 800 and 1200 MHz and is
capable to probe the critical RF magnetic field. The electric and magnetic
field configuration of the Quadrupole Resonator are dependent on the excited
mode. It is shown how this can be used to distinguish between electric and
magnetic losses.Comment: 6 pages, g figure
Western corn rootworm pyrethroid resistance confirmed by aerial application simulations of commercial insecticides
The western corn rootworm (Diabrotica virgifera virgifera LeConte) (WCR) is a major insect pest of corn (Zea mays L.) in the United States (US) and is highly adaptable to multiple management tactics. A low level of WCR field-evolved resistance to pyrethroid insecticides has been confirmed in the US western Corn Belt by laboratory dose-response bioassays. Further investigation has identified detoxification enzymes as a potential part of the WCR resistance mechanism, which could affect the performance of insecticides that are structurally related to pyrethroids, such as organophosphates. Thus, the responses of pyrethroid-resistant and -susceptible WCR populations to the commonly used pyrethroid bifenthrin and organophosphate dimethoate were compared in active ingredient bioassays. Results revealed a relatively low level of WCR resistance to both active ingredients. Therefore, a simulated aerial application bioassay technique was developed to evaluate how the estimated resistance levels would affect performance of registered rates of formulated products. The simulated aerial application technique confirmed pyrethroid resistance to formulated rates of bifenthrin whereas formulated dimethoate provided optimal control. Results suggest that the relationship between levels of resistance observed in dose-response bioassays and actual efficacy of formulated product needs to be further explored to understand the practical implications of resistance
Thiomicrospira arctica sp nov and Thiomicrospira psychrophila sp nov., psychrophilic, obligately chemolithoautotrophic, sulfur-oxidizing bacteria isolated from marine Arctic sediments
Two psychrophilic, chemolithoautotrophic, sulfur-oxidizing bacteria were isolated from marine Arctic sediments sampled off the coast of Svalbard with thiosulfate as the electron donor and CO(2) as carbon source. Comparative analysis of 16S rRNA gene sequences suggested that the novel strains, designated SVAL-D(T) and SVAL-E(T), represent members of the genus Thiomicrospira. Further genotypic (DNA-DNA relatedness, DNA G+C content) and phenotypic characterization revealed that the strains represent members of two novel species. Both organisms are obligately autotrophic and strictly aerobic. Nitrate was not used as an electron acceptor. Chemolithoautotrophic growth was observed with thiosulfate, tetrathionate and sulfur. The temperature limits for growth of both strains were between -2 degrees C and 20.8 degrees C, with optima of 11.5-13.2 degrees C (SVAL-E(T)) and 14.6-15.4 degrees C (SVAL-D(T)), which is about 13-15 degrees C lower than the optima of all other recognized Thiomicrospira species. The maximum growth rate on thiosulfate at 14 degrees C was 0.14 h(-1) for strain SVAL-E(T) and 0.2 h(-1) for strain SVAL-D(T). Major fatty acids of SVAL-D(T) are C(16 : 1), C(18 : 0) and C(16 : 0), and those of SVAL-E(T) are C(16 : 1), C(18 : 1), C(16 : 0) and C(14 : 1). Cells of SVAL-D(T) and SVAL-E(T) are rods, like those of their closest relatives. To our knowledge the novel strains are the first psychrophilic, chemolithoautotrophic, sulfur-oxidizing bacteria so far described. The names Thiomicrospira arctica sp. nov. and Thiomicrospira psychrophila sp. nov. are proposed for SVAL-E(T) (=ATCC 700955(T)=DSM 13458(T)) and SVAL-D(T) (=ATCC 700954(T)=DSM 13453(T)), respectively
NASA Science4Girls and Their Families: Connecting Local Libraries with NASA Scientists and Education Programs to Engage Girls in STEM
NASA Science4Girls and Their Families (NS4G) partners NASA Science Mission Directorate (SMD) education programs with public libraries to provide hands-on science, technology, engineering, and math (STEM) activities and career information for girls and their families, along with training for librarians, in conjunction with Women's History Month (March). NS4G is a collaboration among education teams within the four NASA SMD education and public outreach (E/PO) Forums: Planetary, Earth, Astrophysics, and Heliophysics. It began in 2012 as an Astrophysics-led program (Astro4Girls) with 9 events around the country. Upon expanding among the four Forums, over 73 events were held in Spring 2013 (Fig. 1), with preparations underway for events in Spring 2014. All events are individually evaluated by both the student participants and participating librarians to assess their effectiveness in addressing audience needs
Influences of Orally Taken Carotenoid-Rich Curly Kale Extract on Collagen I/Elastin Index of the Skin
Two differently designed, spatially resolved reflectance spectroscopy-based
scanners and two-photon tomography were used for noninvasive in vivo
determination of cutaneous carotenoids, and collagen I/elastin aging index of
dermis, respectively, in the skin of 29 healthy female volunteers between 40
and 56 years of age. The volunteers received a supplement in the form of a
carotenoid-rich natural curly kale extract containing 1650 µg of carotenoids
in total (three capsules of 550 µg), once a day. Measurements were taken
before, after 5 months and after 10 months of daily supplementation. The
results showed significantly increased values for the cutaneous carotenoids
and the collagen I/elastin aging index of dermis 5 and 10 months after the
beginning of the study. The obtained results show that a natural carotenoid-
rich extract could prevent the aging-related collagen I degradation in the
dermis and improve the extracellular matrix
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Ecological Monitoring of Vascular Plant Resources at the Governor Tom McCall Preserve at Rowena Plateau: Initiation of Long-term Studies for Management.
The bluffs and plateaus of the eastern Columbia River are floristically rich and ecologically intricate. A previous descriptive study of the unique scabland vegetation on the Gov. Tom McCall Preserve at Rowena Plateau in Oregon included delineation of several distinct or intergrading native and non-native vegetation units. In this study we: 1) established permanent transects in the swale-mound mosaic for monitoring compositional changes over time, in order to determine trends in community dynamics; 2) implemented a permanent plot system to monitor population demography of Astragalus hoodianus; and 3) resampled the vernal pool communities. Monitoring of the vegetation existing in the swale-mound mosaic grasslands is expected to provide information regarding whether the exotic annuals are continuing to increase at the expense of the indigenous flora, or if an equilibrium has been reached due to the cessation of grazing. Astragalus hoodianus is a rare and potentially threatened endemic, thus it is important to monitor this population's stability in terms of recruitment, mortality, and the apparent effects of competing vegetation on recruitment and on mortality
A process calculus with finitary comprehended terms
We introduce the notion of an ACP process algebra and the notion of a meadow
enriched ACP process algebra. The former notion originates from the models of
the axiom system ACP. The latter notion is a simple generalization of the
former notion to processes in which data are involved, the mathematical
structure of data being a meadow. Moreover, for all associative operators from
the signature of meadow enriched ACP process algebras that are not of an
auxiliary nature, we introduce variable-binding operators as generalizations.
These variable-binding operators, which give rise to comprehended terms, have
the property that they can always be eliminated. Thus, we obtain a process
calculus whose terms can be interpreted in all meadow enriched ACP process
algebras. Use of the variable-binding operators can have a major impact on the
size of terms.Comment: 25 pages, combined with arXiv:0901.3012 [math.RA]; presentation
improved, mistakes in Table 5 correcte
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