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1.
This article enhances the notion of city‐making by explicating its communicative processes and functions within the press. Through a quantitative content analysis and qualitative textual analysis of Miami Herald news coverage related to incorporation and annexation policies and practices over a period of 3 years, we argue for a stronger implication of the press in coverage of local policy‐ and place‐making. Through a quantitative content analysis of 437 articles from the Miami Herald about communities affected by incorporation and annexation and a qualitative textual analysis of 51 articles related to general coverage of geographic policy‐making in Miami‐Dade County over a 3‐year period, we argue that this coverage reveals the press as being a central feature and function of policy‐making through the lens of city‐making. 相似文献
2.
Abstract Error-diffused quantization has been applied to the generation of cell-oriented computer-generated Fourier transform holograms, resulting in reduced reconstruction errors. Improvements are demonstrated when applied to the algorithms of Lohmann, Lee and Burckhardt after invoking realistic constraints on the minimum size of the printable spot for an electrophotographic laser printer. 相似文献
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Drugs that decrease drug-maintained responding at doses that do not decrease other behaviors in animals may be suitable candidates for development as medications to treat drug abuse in humans. The present study examined whether this effect could be obtained with phentermine, a drug that has been reported to decrease cocaine intake in humans. Rhesus monkeys were trained under multiple fixed-ratio 30-response schedules of food and i.v. cocaine delivery. Phentermine was always given as a slow, i.v. infusion. Acute treatment with phentermine (0.3-10 mg/kg) decreased cocaine-maintained responding at doses that did not decrease, or decreased less, food-maintained responding for each of three unit doses of cocaine (10-100 microg/kg/injection). Subacute treatment with phentermine (3 or 5.6 mg/kg, daily) also decreased cocaine-maintained responding more than food-maintained responding. After subacute treatment was terminated, rates of cocaine-maintained responding generally recovered to levels comparable to those seen during untreated control sessions. Phentermine (0.3-3 mg/kg) did not generally increase responding associated with a very low (1 microg/kg/injection) unit dose of cocaine, suggesting that the decrease in cocaine-maintained responding at higher unit doses was not the result of a leftward shift in the cocaine unit dose-effect function. Phentermine (0.1-3 mg/kg) decreased responding maintained by 1-[2-[bis(4-fluorophenyl) methoxy]ethyl]-4-[3-phenylpropyl] piperazine (GBR 12909) (30 microg/kg/injection) at doses similar to those that decreased food-maintained responding. These results show that phentermine is effective in decreasing cocaine self-administration and suggest that it may be an effective medication for cocaine abuse. 相似文献
5.
Balanced genetic polymorphism has been proposed as a source from which to infer population history complementary to that of neutral genetic polymorphism, because genetic polymorphism maintained by balancing selection permits inferences about population size over much longer spans of time. However, empirical data for both S genes and major histocompatibility complex genes do not fit expectations of coalescent theory. Species-specific gene genealogies have longer terminal branches than expected, indicating an apparent slowdown in the origination of new alleles. Here, we present evidence that divergent S alleles were selectively maintained in Physalis cinerascens during a reduction in population size, generating longer terminal branches in the S gene genealogy relative to the congener Physalis crassifolia. Retention of divergent alleles during reduction in the number of alleles violates assumptions of the coalescent model used to estimate effective population size. Recent theoretical and empirical results are consistent with the proposition that nonrandom sorting is a general property of balanced genetic polymorphisms, suggesting that studies of balanced polymorphism that infer the absence of population bottlenecks may overestimate effective population size. 相似文献
6.
Single-fluorophore imaging with an unmodified epifluorescence microscope and conventional video camera 总被引:1,自引:0,他引:1
Single fluorophores in aqueous solution were imaged in real time with a conventional silicon-intensified target video camera connected to an unmodified commercial microscope (IX70, Olympus) with epifluorescence excitation with a high-pressure mercury lamp. Neither a powerful laser nor an extremely sensitive video camera was required. Three experimental systems were used to demonstrate quantitatively that individual, moving or stationary Cy3 fluorophores could be imaged with the microscope: Cy3-gelsolin attached to an actin filament sliding over heavy meromyosin, sliding actin filaments sparsely labelled with Cy3, and heavy meromyosin labelled with one or two Cy3 fluorophores. The results should encourage many laboratories to attempt 'single-molecule physiology' in which the functions and mechanisms of molecular machines are studied at the single-molecule level in an environment where the biological machines are fully active. 相似文献
7.
PARTIAL PURIFICATION AND CHARACTERIZATION OF A THERMOSTABLE TRYPSIN FROM PYLORIC CAECA OF TAMBAQUI (COLOSSOMA MACROPOMUM) 总被引:2,自引:0,他引:2
RANILSON S. BEZERRA JULIANA F. SANTOS PATRÍCIA M.G. PAIVA MARIA T.S. CORREIA LUANA C.B.B. COELHO VERA L.A. VIEIRA LUIZ B. CARVALHO JR. 《Journal of Food Biochemistry》2001,25(3):199-210
A 38.5 kDa alkaline protease from pyloric caeca of tambaqui (Colossoma macropomumj, a tropical freshwater fish, was partially purified in three steps: thermal treatment (45Cfor 30 min), salting‐out (ammonium sulfate at 40–80% of saturation) and gel filtration (Sephadex G‐75), The purification and yield were 51.2‐fold and 40%, respectively. The effects of pH, temperature, inhibitors, and substrates on proteolytic activities of partially purified enzyme were investigated. The optimum pH was 9.5, while the optimum temperature was 60C. This alkaline proteolytic activity remained unaltered after 30 min incubation at 55C. Active site inhibition provided additional evidence that this activity is attributed to a trypsin‐like enzyme. 相似文献
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M Delgado C Martinez D Pozo JR Calvo J Leceta D Ganea RP Gomariz 《Canadian Metallurgical Quarterly》1999,162(2):1200-1205
The neuropeptides vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating polypeptide (PACAP) down-regulate cytokine production. Because human septic shock involves excessive cytokine production, the effect of VIP/PACAP was investigated in a high endotoxemia murine model. Both peptides protect against endotoxin-induced lethality and prevent septic shock-associated histopathological alterations. VIP/PACAP reduce serum and peritoneal TNF-alpha and IL-6, suggesting that the protective effect is exerted by inhibiting the production of endogenous TNF-alpha/IL-6. Consistent with this mechanism, VIP does not protect against septic shock induced by exogenous TNF-alpha. The immunomodulatory role of VIP in vivo is supported by the appearance of high levels of VIP in serum and peritoneal fluid following LPS administration. Thus, the neuropeptides VIP/PACAP protect from the lethal effect of high endotoxemia, presumably by down-regulating TNF-alpha and IL-6 production, and may offer an alternative in the treatment of human septic shock syndrome. 相似文献
10.
Previous studies suggest that performance of a series system may be enhanced if those station(s) having smallest mean operation time requirement(s) and/or smallest variability are placed in the middle of the line. There has been considerable confusion relative to whether this ‘bowl phenomenon’ has to do with the placement of means, variances, or some combination of the two. The results of the current study show that the phenomenon observed is not related to an imbalance in means. Rather, it is associated with an imbalance in absolute variability. Furthermore, it is suggested that the bowl effect vanishes altogether in cases where a minimal level of in-process buffer stock is provided. 相似文献