5,381 research outputs found

    Dynamic wind loading of H-shaped tall buildings

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    Fulltext in: http://www.iawe.org/Proceedings/7APCWE/M3A_5.pdfTechnical Session: M3-A High-Rise Building, no.5Dynamic wind loads on a number of H-shaped tall buildings are measured in the wind tunnel with a highfrequency force balance for all wind incidences. The aim is to investigate the size effect of the recessed cavities on the dynamic wind loading behavior of the building. Combinations of three widths and three depths of a cavity are tested. It is found that at most wind incidences, the presence of cavities on the building faces leads to little modifications to the magnitudes and behavior of mean and fluctuating overturning moment coefficients. However, reduced magnitudes of across-wind moment fluctuations are found at normal incidence and different behavior of across-wind excitation is revealed by the across-wind moment spectra. Wind torsion is noticeably modified by the presence of the recessed cavities.link_to_subscribed_fulltex

    The surface accessibility of α-bungarotoxin monitored by a novel paramagnetic probe

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    The surface accessibility of {alpha}-bungarotoxin has been investigated by using Gd2L7, a newly designed paramagnetic NMR probe. Signal attenuations induced by Gd2L7 on {alpha}-bungarotoxin C{alpha}H peaks of 1H-13C HSQC spectra have been analyzed and compared with the ones previously obtained in the presence of GdDTPA-BMA. In spite of the different molecular size and shape, for the two probes a common pathway of approach to the {alpha}-bungarotoxin surface can be observed with an equally enhanced access of both GdDTPA-BMA and Gd2L7 towards the protein surface side where the binding site is located. Molecular dynamics simulations suggest that protein backbone flexibility and surface hydration contribute to the observed preferential approach of both gadolinium complexes specifically to the part of the {alpha}-bungarotoxin surface which is involved in the interaction with its physiological target, the nicotinic acetylcholine receptor

    Rats distinguish between absence of events and lack of evidence in contingency learning.

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    The goal of three experiments was to study whether rats are aware of the difference between absence of events and lack of evidence. We used a Pavlovian extinction paradigm in which lights consistently signaling sucrose were suddenly paired with the absence of sucrose. The crucial manipulation involved the absent outcomes in the extinction phase. Whereas in the Cover conditions, access to the drinking receptacle was blocked by a metal plate, in the No Cover conditions, the drinking receptacle was accessible. The Test phase showed that in the Cover conditions, the measured expectancies of sucrose were clearly at a higher level than in the No Cover conditions. We compare two competing theories potentially explaining the findings. A cognitive theory interprets the observed effect as evidence that the rats were able to understand that the cover blocked informational access to the outcome information, and therefore the changed learning input did not necessarily signify a change of the underlying contingency in the world. An alternative associationist account, renewal theory, might instead explain the relative sparing of extinction in the Cover condition as a consequence of context change. We discuss the merits of both theories as accounts of our data and conclude that the cognitive explanation is in this case preferred

    An Algebraic Characterization of Equivalent Bayesian Networks

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    The BRG1 transcriptional coregulator

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    The packaging of genomic DNA into chromatin, often viewed as an impediment to the transcription process, plays a fundamental role in the regulation of gene expression. Chromatin remodeling proteins have been shown to alter local chromatin structure and facilitate recruitment of essential factors required for transcription. Brahma-related gene-1 (BRG1), the central catalytic subunit of numerous chromatin-modifying enzymatic complexes, uses the energy derived from ATP-hydrolysis to disrupt the chromatin architecture of target promoters. In this review, we examine BRG1 as a major coregulator of transcription. BRG1 has been implicated in the activation and repression of gene expression through the modulation of chromatin in various tissues and physiological conditions. Outstanding examples are studies demonstrating that BRG1 is a necessary component for nuclear receptor-mediated transcriptional activation. The remodeling protein is also associated with transcriptional corepressor complexes which recruit remodeling activity to target promoters for gene silencing. Taken together, BRG1 appears to be a critical modulator of transcriptional regulation in cellular processes including transcriptional regulation, replication, DNA repair and recombination

    Application of a VUV fourier transform spectrometer and synchrotron radiation source to measurements of. VI. The ε(0,0) band of NO

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    The analysis of the ε(0,0) band around 187.6 nm was reported using the VUV FTS with synchrotron radiation for the background source. Due to the capability of the combintion of instruments, These were the first high-resolution quantitative measurements of line positions and intensities of the rotational lines of the ε(0,0) band. The determination of the band oscillator strengths of the band was performed using line-by-line measurements, because the resolution of the present experiment was comparable to the Doppler widths.published_or_final_versio

    Influences of Excluded Volume of Molecules on Signaling Processes on Biomembrane

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    We investigate the influences of the excluded volume of molecules on biochemical reaction processes on 2-dimensional surfaces using a model of signal transduction processes on biomembranes. We perform simulations of the 2-dimensional cell-based model, which describes the reactions and diffusion of the receptors, signaling proteins, target proteins, and crowders on the cell membrane. The signaling proteins are activated by receptors, and these activated signaling proteins activate target proteins that bind autonomously from the cytoplasm to the membrane, and unbind from the membrane if activated. If the target proteins bind frequently, the volume fraction of molecules on the membrane becomes so large that the excluded volume of the molecules for the reaction and diffusion dynamics cannot be negligible. We find that such excluded volume effects of the molecules induce non-trivial variations of the signal flow, defined as the activation frequency of target proteins, as follows. With an increase in the binding rate of target proteins, the signal flow varies by i) monotonically increasing; ii) increasing then decreasing in a bell-shaped curve; or iii) increasing, decreasing, then increasing in an S-shaped curve. We further demonstrate that the excluded volume of molecules influences the hierarchical molecular distributions throughout the reaction processes. In particular, when the system exhibits a large signal flow, the signaling proteins tend to surround the receptors to form receptor-signaling protein clusters, and the target proteins tend to become distributed around such clusters. To explain these phenomena, we analyze the stochastic model of the local motions of molecules around the receptor.Comment: 31 pages, 10 figure

    Cloud-based genomics pipelines for ophthalmology: Reviewed from research to clinical practice

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    Aim: To familiarize clinicians with clinical genomics, and to describe the potential of cloud computing for enabling the future routine use of genomics in eye hospital settings. Design: Review article exploring the potential for cloud-based genomic pipelines in eye hospitals. Methods: Narrative review of the literature relevant to clinical genomics and cloud computing, using PubMed and Google Scholar. A broad overview of these fields is provided, followed by key examples of their integration. Results: Cloud computing could benefit clinical genomics due to scalability of resources, potentially lower costs, and ease of data sharing between multiple institutions. Challenges include complex pricing of services, costs from mistakes or experimentation, data security, and privacy concerns. Conclusions and future perspectives: Clinical genomics is likely to become more routinely used in clinical practice. Currently this is delivered in highly specialist centers. In the future, cloud computing could enable delivery of clinical genomics services in non-specialist hospital settings, in a fast, cost-effective way, whilst enhancing collaboration between clinical and research teams

    Mean-field cooperativity in chemical kinetics

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    We consider cooperative reactions and we study the effects of the interaction strength among the system components on the reaction rate, hence realizing a connection between microscopic and macroscopic observables. Our approach is based on statistical mechanics models and it is developed analytically via mean-field techniques. First of all, we show that, when the coupling strength is set positive, the model is able to consistently recover all the various cooperative measures previously introduced, hence obtaining a single unifying framework. Furthermore, we introduce a criterion to discriminate between weak and strong cooperativity, based on a measure of "susceptibility". We also properly extend the model in order to account for multiple attachments phenomena: this is realized by incorporating within the model pp-body interactions, whose non-trivial cooperative capability is investigated too.Comment: 25 pages, 4 figure
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