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2.
The diversity of fish species found in warmwater stream systems provides a perplexing challenge when selecting species for assessment of instream flow needs from physical habitat analyses. In this paper we examined the feasibility of developing habitat suitability criteria (HSC) for the entire fish community of a warmwater stream using habitat guilds. Each species was placed a priori into a guild structure and habitat data were collected for depth, velocity, Froude number, distance to cover, embeddedness and dominant and subdominant substrate. Correct guild classification was tested with linear discriminant analysis for each species. Correct classification based on habitat‐use data was highest for riffle and pool‐cover guilds, whereas the fast‐generalist and pool‐run classes, the broader niche guilds, were more frequently misclassified. Variables most important for discriminating guilds were Froude number, velocity and depth in that order. Nonparametric tolerance limits were used to develop guild suitability criteria for continuous variables and the Strauss linear index was used for categorical variables. We recommend the use of a wide array of variables to establish more accurate habitat analysis. Additionally, guild HSC can be developed with similar effort to that needed to develop HSC for a small number of individual species. Results indicate that a habitat guild structure can be successfully transferred to another river basin and that habitats for a diverse fish assemblage can be adequately described by a small number of habitat guilds. This approach represents an alternative for incorporating entire fish assemblages into habitat analyses of warmwater stream systems. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   
3.
Diode-Pumped Solid-State Lasers for Inertial Fusion Energy   总被引:5,自引:0,他引:5  
We have begun building the Mercury laser system as the first in a series of new generation diode-pumped solid-state lasers for inertial fusion research. Mercury will integrate three key technologies: diodes, crystals, and gas cooling, within a unique laser architecture that is scalable to kilojoule and megajoule energy levels for fusion energy applications. The primary near-term performance goals include 10% electrical efficiencies at 10 Hz and 100J with a 2–10 ns pulse length at 1.047 m wavelength. When completed, Mercury will allow rep-rated target experiments with multiple chambers for high energy density physics research.  相似文献   
4.
The authors examined the development of self-esteem from young adulthood to old age. Data came from the Americans’ Changing Lives study, which includes 4 assessments across a 16-year period of a nationally representative sample of 3,617 individuals aged 25 years to 104 years. Latent growth curve analyses indicated that self-esteem follows a quadratic trajectory across the adult life span, increasing during young and middle adulthood, reaching a peak at about age 60 years, and then declining in old age. No cohort differences in the self-esteem trajectory were found. Women had lower self-esteem than did men in young adulthood, but their trajectories converged in old age. Whites and Blacks had similar trajectories in young and middle adulthood, but the self-esteem of Blacks declined more sharply in old age than did the self-esteem of Whites. More educated individuals had higher self-esteem than did less educated individuals, but their trajectories were similar. Moreover, the results suggested that changes in socioeconomic status and physical health account for the decline in self-esteem that occurs in old age. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
5.
An electrospray ionization source for integration with microfluidics   总被引:3,自引:0,他引:3  
We have demonstrated a new electrospray ionization (ESI) device incorporating a tip made from a shaped thin film, bonded to a microfluidic channel, and interfaced to a time-of-flight mass spectrometer (TOFMS). A triangular-shaped thin polymer tip was formed by lithography and etching. A microfluidic channel, 20 microm wide and 10 microm deep, was embossed in a cyclo olefin substrate using a silicon master. The triangular tip was aligned with the channel and bonded between the channel plate and a flat plate to create a microfluidic channel with a wicking tip protruding from the end. This structure aided the formation of a stable Taylor cone at the apex of the tip, forming an electrospray ionization source. This source was tested by spraying several solutions for mass spectrometric analysis. Because the components are all made by lithographic approaches with high geometrical fidelity, an integrated array system with multiple channels can be formed with the same method and ease as a single channel. We tested a multichannel system in a multiplexed manner and showed reliable operation with no significant cross contamination between closely spaced channels.  相似文献   
6.
A time-consuming sample preparation and measuring procedure is required for the quantitation of retinyl palmitate by HPLC. We developed a fluorometric method for the determination of total retinyl esters in chylomicrons, chylomicron remnants, and VLDL. This method is precise, sensitive, rapid, simple, and particularly useful for large-scale studies of postprandial lipid metabolism. Because the turbidity of postprandial lipemic samples interferes with the fluorescence measurement, all samples were incubated for 10 min with a clearing buffer containing esterase and detergents. This buffer eliminates the turbidity and hydrolyzes all retinyl esters to retinol. The fluorescence signal (excitation wavelength, 330 nm; emission wavelength, 490 nm) was linear from 0.1 mg/L up to 4 mg/L retinyl palmitate, and the CVs were 3.6% within-run and 5.1% within-series. A first application studied postprandial lipoproteins, which were first separated by ultracentrifugation and then subjected to size exclusion chromatography. Fluorescence analysis revealed that the chylomicron density fraction contains large amounts of chylomicron remnants.  相似文献   
7.
PR-toxinbildung bei penicillium roqueforti-st?mmen   总被引:2,自引:0,他引:2  
Zusammenfassung Eine Blauschimmelkäse-Starterkultur und 11Penicillium roqueforti-Isolate von verschiedenen Lebensmitteln wurden auf die Bildung von PR-Toxin untersucht. Bei 3 Stämmen konnte Toxinbildung auf Reis bei 15° C und vereinzelt auch bei 30° C nachgewiesen werden. Die Toxinmengen lagen zwischen 310 und 960 ppb. Bei derP. roqueforti-Starterkultur konnte kein Toxin nachgewiesen werden. Bei Versuchen mitP. roqueforti NRRL 849 zeigte sich, daß das Toxin im Temperaturbereich von 15-30° C, mit einem Optimum bei 15°C, gebildet werden kann, während das Wachstums-Optimum bei 25°C liegt. PR-Toxin wurde dünnschichtchromatographisch bestimmt; zweifelhafte Fälle wurden massenspektrometrisch überprüft.
PR-toxin-production of penicillium roqueforti-strains
Summary One blue-type cheese starter and 11 isolates ofP. roqueforti from different foodstuffs were tested for the production of PR-toxin. 3 strains were able to produce the toxin on rice at 15° C and sometimes at 30° C. The toxin quantities detected were 310–960 ppb. The starter culture didn't produce any PR-toxin. The investigations withP. roqueforti NRRL 849 showed a toxin-production in the temperature range of 15–30° C, with an optimum at 15° C, whereas 25° C was the optimum for growth. PR-toxin was determined by thin-layer-chromatography and in doubtful cases by mass-spectrometry.


Die Arbeit wurde mit Unterstützung des BMJFG durchgeführt.  相似文献   
8.
Evolving access networks: a European perspective   总被引:1,自引:0,他引:1  
The diversity of telecommunications markets and access network infrastructure among the countries of Europe is a complicating factor in the development of effective standards for Europe's future access networks. The need for evolving access networks to make efficient use of a wide variety of existing infrastructure may at times conflict with the long-term requirement for a stable platform of self-consistent standards which allow future-proof evolution. In light of these constraints, the authors summarize progress made in the European Telecommunications Standards Institute (ETSI) toward standards for future access networks  相似文献   
9.
River regulation has resulted in substantial losses in habitat connectivity, biodiversity and ecosystem services. River managers are faced with a growing need to protect the key aspects of the natural flow regime. A practical approach to providing environmental flow standards is to create a regional framework by classifying unregulated streams into groups of similar hydrologic properties, which represent natural flow regime targets. Because spatial resolution can influence the structure of regional datasets, it may be advantageous to relate datasets created at different scales in order to establish hierarchical structure and to understand how the relative importance of variables change with regard to scale. The purpose of this study was to classify unregulated streams within an eight‐state region into groups in order to provide environmental flow standards for managers and to relate that dataset to frameworks created at larger scales. Using USGS daily stream gauge information, we used 66 hydrologic statistics to classify 292 streams in groups of similar hydrologic properties. We isolated six flow classes in a sub‐region of the Southeastern US that ranged from extremely stable to highly variable to intermittent. We developed classification trees to reduce the number of hydrologic variables for future classifications. By comparing flow classes in our study to those of the entire US, we found that hierarchical structure did exist and that the divergence of flow classes will largely depend on the spatial resolution. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   
10.
We have isolated selective ligands to the cell surface receptors of fibronectin (alpha 5 beta 1 integrin), vitronectin (alpha v beta 3 and alpha v beta 5 integrins) and fibrinogen (alpha IIb beta 3 integrin) from phage libraries expressing cyclic peptides. A mixture of libraries was used that express a series of peptides flanked by a cysteine residue on each side (CX5C, CX6C, CX7C) or only on one side (CX9) of the insert. A majority of the integrin-binding sequences derived from the CX9 library contained another cysteine, indicating preferential selection of conformationally constrained cyclic peptides. Each of the four integrins studied primarily selected RGD-containing phage sequences but favored different ring sizes and different flanking residues around the RGD motif. A cyclic peptide ACRGDGWCG was synthesized based on a phage sequence that bound particularly avidly to the alpha 5 beta 1 integrin. This peptide inhibited cell attachment to fibronectin at about 5-fold lower concentrations than the most potent cyclic peptides described earlier. The most interesting structure appeared to contain two disulphide bonds. One such peptide, ACDCRGDCFCG, was synthetized and shown to be at least 20-fold more potent inhibitor of alpha v beta 5- and alpha v beta 3-mediated cell attachment to vitronectin than similar peptides with a single disulphide bond and 200-fold more potent than commonly used linear RGD peptides. These results emphasize the importance of conformational restriction as a means of improving the potency of integrin-binding peptides and point to a new way of designing effective peptides by resticting the peptide conformation with more than one cyclizing bond.  相似文献   
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