891 resultados para race mixing
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The aim of this study was to investigate the effects of different swimming race constraints on the evolution of turn parameters. One hundred and fifty-eight national and regional level 200-m (meters) male swimming performances were video-analyzed using the individualized-distance model in the Open Comunidad de Madrid tournament. Turn (p < .001, ES = 0.36) and underwater distances (p < .001, ES = 0.38) as well as turn velocity (p < .001, ES = 0.69) significantly dropped throughout the race, although stroke velocity and underwater velocity were maintained in the last lap of the race (p > .05). Higher expertise swimmers obtained faster average velocities and longer distances in all the turn phases (p < .001, ES = 0.59), except the approach distance. In addition, national level swimmers showed the ability to maintain most of the turn parameters throughout the race, which assisted them in improving average velocity at the end of races. Therefore, the variations in the turning movements of a swimming race were expertise-related and focused on optimizing average velocity. Turning skills should be included in the swimming race action plan.
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In this paper, a hydroelectric power plant with long tail-race tunnel has been modelled for assessing its contribution to secondary regulation reserve. Cavitation problems, caused by the discharge conduit length, are expected downstream the turbine where low pressure appears during regulation manoeuvres. Therefore, governor's gains should be selected taking into account these phenomena. On the other hand, regulation services bidden by the plant operator should fulfil TSO (Transmission System Operator) quality requirements. A methodology for tuning governor PI gains is proposed and applied to a Hydro power plant in pre-design phase in northwest area of Spain. The PI gains adjustment proposed provides a proper plant response, according to some established indexes, while avoiding cavitation phenomena.
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Pumped storage hydro plants (PSHP) can provide adequate energy storage and frequency regulation capacities in isolated power systems having significant renewable energy resources. Due to its high wind and solar potential, several plans have been developed for La Palma Island in the Canary archipelago, aimed at increasing the penetration of these energy sources. In this paper, the performance of the frequency control of La Palma power system is assessed, when the demand is supplied by the available wind and solar generation with the support of a PSHP which has been predesigned for this purpose. The frequency regulation is provided exclusively by the PSHP. Due to topographic and environmental constraints, this plant has a long tail-race tunnel without a surge tank. In this configuration, the effects of pressure waves cannot be neglected and, therefore, usual recommendations for PID governor tuning provide poor performance. A PI governor tuning criterion is proposed for the hydro plant and compared with other criteria according to several performance indices. Several scenarios considering solar and wind energy penetration have been simulated to check the plant response using the proposed criterion. This tuning of the PI governor maintains La Palma system frequency within grid code requirements.
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Keynote Speaker
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https://bluetigercommons.lincolnu.edu/pli/1008/thumbnail.jpg
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Membrane bilayer fusion has been shown to be mediated by v- and t-SNAREs initially present in separate populations of liposomes and to occur with high efficiency at a physiologically meaningful rate. Lipid mixing was demonstrated to involve both the inner and the outer leaflets of the membrane bilayer. Here, we use a fusion assay that relies on duplex formation of oligonucleotides introduced in separate liposome populations and report that SNARE proteins suffice to mediate complete membrane fusion accompanied by mixing of luminal content. We also find that SNARE-mediated membrane fusion does not compromise the integrity of liposomes.
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Nicotiana tabacum 46-8 cultivar displays an incompatible interaction with race 0 of Phytophthora parasitica var. nicotianae (Ppn), a fungal pathogen of most tobacco cultivars. At the plant level, incompatibility is characterized by the induction of lipoxygenase (LOX, EC = 1.13.11.12) activity and localized hypersensitive cell death before defense gene activation. To evaluate the involvement of LOX in the onset of plant defense, tobacco 46-8 plants were genetically engineered using full-length or partial-length antisense (AS) tobacco LOX cDNA constructs. AS expression strongly reduced elicitor- and pathogen-induced LOX activity. Eight independent AS-LOX lines were selected and assayed for their response to Ppn. After root or stem inoculation with race 0, all AS-LOX lines but one displayed a compatible phenotype whereas control transformed plants, not containing the AS-LOX cassette, showed the typical incompatible reaction. The presence of the fungus in transgenic lines was demonstrated by PCR amplification of a Ppn-specific genomic sequence. A linear relationship was found between the extent of LOX suppression and the size of the lesion caused by the fungus. The AS-LOX plants also showed enhanced susceptibility toward the compatible fungus Rhizoctonia solani. The results demonstrate the strong involvement of LOX in the establishment of incompatibility in plant–microorganism interactions, consistent with its role in the defense of host plants.
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Ligand transport through myoglobin (Mb) has been observed by using optically heterodyne-detected transient grating spectroscopy. Experimental implementation using diffractive optics has provided unprecedented sensitivity for the study of protein motions by enabling the passive phase locking of the four beams that constitute the experiment, and an unambiguous separation of the Real and Imaginary parts of the signal. Ligand photodissociation of carboxymyoglobin (MbCO) induces a sequence of events involving the relaxation of the protein structure to accommodate ligand escape. These motions show up in the Real part of the signal. The ligand (CO) transport process involves an initial, small amplitude, change in volume, reflecting the transit time of the ligand through the protein, followed by a significantly larger volume change with ligand escape to the surrounding water. The latter process is well described by a single exponential process of 725 ± 15 ns at room temperature. The overall dynamics provide a distinctive signature that can be understood in the context of segmental protein fluctuations that aid ligand escape via a few specific cavities, and they suggest the existence of discrete escape pathways.
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Gap junctions are plaque-like clusters of intercellular channels that mediate intercellular communication. Each of two adjoining cells contains a connexon unit which makes up half of the whole channel. Gap junction channels are formed from a multigene family of proteins called connexins, and different connexins may be coexpressed by a single cell type and found within the same plaque. Rodent gap junctions contain two proteins, connexins 32 and 26. Use of a scanning transmission electron microscope for mass analysis of rodent gap junction plaques and split gap junctions prvided evidence consistent with a model in which the channels may be made from (i) solely connexin 26, (ii) solely connexin 32, or (iii) mixtures of connexin 26 and connexin 32 in which the two connexons are made entirely of connexin 26 and connexin 32. The different types of channels segregate into distinct domains, implying tha connexon channels self-associate to give a non-random distribution within tissues. Since each connexin confers distinct physiological properties on its membrane channels, these results imply that the physiological properties of channels can be tailored by mixing the constituent proteins within these macromolecular structures.
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This study was a qualitative examination of Black college students' experiences with the Acting White label. In conducting this study, two gaps in literature were addressed: (1) the lack of literature on Black college students and the acting white label, and (2) lack of attention to a US racial history and current structures which allow a label such as "acting white" to exist. Thus, the purpose of this study was to call attention to the experiences of Black college students as it relates to the acting white label. Additionally, the study calls attention to social constructions that allow the acting white label to exist and to be sustained. Data was collected from 14 Black college students at a predominantly white, private, liberal arts university in the west. Based on responses from students in the study, Black college students do hear that they are acting white. Yet, their reaction to hearing the label does not cause them to underachieve academically, but does have an impact on their social actions. The ways in which Black college students in the study were labeled as acting white was based on academic pursuits, speech patterns, dress, and hobbies. Student reactions to the label ranged from ignoring the label to challenging the accuser. In regards to how the acting white label is sustained, students in the study expressed that they learned what it meant to act white or black from family interactions, social interactions and observations from family and friends, and from media sources. It was concluded that Black college students, despite reactions, do hear the label and that the label seems to be used as a means to attack Black students and their identity.
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This Article demonstrates through original statistical research that prosecutors in Colorado were more likely to seek the death penalty against minority defendants than against white defendants. Moreover, defendants in Colorado’s Eighteenth Judicial District were more likely to face a death prosecution than defendants elsewhere in the state. Our empirical analysis demonstrates that even when one controls for the differential rates at which different groups commit statutorily death-eligible murders, non-white defendants and defendants in the Eighteenth Judicial District were still more likely than others to face a death penalty prosecution. Even when the heinousness of the crime is accounted for, the race of the accused and the place of the crime are statistically significant predictors of whether prosecutors will seek the death penalty. We discuss the implications of this disparate impact on the constitutionality of Colorado’s death penalty regime, concluding that the Colorado statute does not meet the dictates of the Eighth Amendment to the Constitution.
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ESAT 2014. 27th European Symposium on Applied Thermodynamics, Eindhoven University of Technology, July 6-9, 2014.