965 research outputs found

    Laser application to measure vertical sea temperature and turbidity, design phase

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    An experiment to test a new method was designed, using backscattered radiation from a laser beam to measure oceanographic parameters in a fraction of a second. Tyndall, Rayleigh, Brillouin, and Raman scattering all are utilized to evaluate the parameters. A beam from a continuous argon ion laser is used together with an interferometer and interference filters to gather the information. The results are checked by direct measurements. Future shipboard and airborne experiments are described

    Requirement Analysis and Implementation of Multicriteria Analysis in the NEEDS Project

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    This report specifies the requirements for and implementation of the multicriteria analysis of future energy technologies performed by a large number of stakeholders within the EU-funded integrated projct NEEDS. The report is composed of two main parts and the appendix. The first part starts with a summary of the objectives of the analysis followed by a detailed specifiation of the analyzed problem, in particular the analysis context, discussion of the sets of criteria and alternatives, and the participation of the stakeholders. Next, the planned problem analysis process is first outlined, and then discussed in more detail. Finally, the requirements for the multicritria analysis are specified. The second part deals with the implementation of the dedicated Web-site developed for this analysis, and later extended to support analysis of any multicriteria choice between discrete alternatives. It starts with an overview of the problem analysis process and the corresponding basic assumptions. Te architecture of the application and its features are then presented. Lessons learned from the development and use of this application conclude this part of the report. The appendix contains a review of the state-of-the-art of applying multicriteria analysis to energy problems, as well as characteristics of three applications that exploit the multicriteria analysis methods for energy problems considered relevant to the analysis reported in this paper

    Improved Algorithms for Approximate String Matching (Extended Abstract)

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    The problem of approximate string matching is important in many different areas such as computational biology, text processing and pattern recognition. A great effort has been made to design efficient algorithms addressing several variants of the problem, including comparison of two strings, approximate pattern identification in a string or calculation of the longest common subsequence that two strings share. We designed an output sensitive algorithm solving the edit distance problem between two strings of lengths n and m respectively in time O((s-|n-m|)min(m,n,s)+m+n) and linear space, where s is the edit distance between the two strings. This worst-case time bound sets the quadratic factor of the algorithm independent of the longest string length and improves existing theoretical bounds for this problem. The implementation of our algorithm excels also in practice, especially in cases where the two strings compared differ significantly in length. Source code of our algorithm is available at http://www.cs.miami.edu/\~dimitris/edit_distanceComment: 10 page

    Guanosine diphosphatase is required for protein and sphingolipid glycosylation in the Golgi lumen of Saccharomyces cerevisiae

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    Current models for nucleotide sugar use in the Golgi apparatus predict a critical role for the lumenal nucleoside diphosphatase. After transfer of sugars to endogenous macromolecular acceptors, the enzyme converts nucleoside diphosphates to nucleoside monophosphates which in turn exit the Golgi lumen in a coupled antiporter reaction, allowing entry of additional nucleotide sugar from the cytosol. To test this model, we cloned the gene for the S. cerevisiae guanosine diphosphatase and constructed a null mutation. This mutation should reduce the concentrations of GDP-mannose and GMP and increase the concentration of GDP in the Golgi lumen. The alterations should in turn decrease mannosylation of proteins and lipids in this compartment. In fact, we found a partial block in O- and N-glycosylation of proteins such as chitinase and carboxypeptidase Y and underglycosylation of invertase. In addition, mannosylinositolphosphorylceramide levels were drastically reduced

    Evaluation of a method to calculate debris-flow volume based on observations of flow depth

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    The volume of a debris flow is a critical parameter in hazard analysis, yet accurate estimates of volume are often unavailable due to mixing with larger rivers at the downstream end of alluvial fans. We describe a method to calculate the volume of debris flows using flow depth data collected at a check dam, using a Manning friction relation to describe the velocity of the debris flow as a function of flow depth, and the geometry of the channel cross section. The method is evaluated using a published data set from the USGS debris-flow flume where event volume and stage information have been accurately measured, and results in volume estimates either somewhat smaller than or up to 50% larger than observed volumes. We further demonstrate the method to single-surge and a multiple-surge debris flows observed at Illgraben

    Retrograde optogenetic characterization of the pontospinal module of the locus coeruleus with a canine adenoviral vector

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    AbstractNoradrenergic neurons of the brainstem extend projections throughout the neuraxis to modulate a wide range of processes including attention, arousal, autonomic control and sensory processing. A spinal projection from the locus coeruleus (LC) is thought to regulate nociceptive processing. To characterize and selectively manipulate the pontospinal noradrenergic neurons in rats, we implemented a retrograde targeting strategy using a canine adenoviral vector to express channelrhodopsin2 (CAV2-PRS-ChR2-mCherry). LC microinjection of CAV2-PRS-ChR2-mCherry produced selective, stable, transduction of noradrenergic neurons allowing reliable opto-activation in vitro. The ChR2-transduced LC neurons were opto-identifiable in vivo and functional control was demonstrated for >6 months by evoked sleep-wake transitions. Spinal injection of CAV2-PRS-ChR2-mCherry retrogradely transduced pontine noradrenergic neurons, predominantly in the LC but also in A5 and A7. A pontospinal LC (ps:LC) module was identifiable, with somata located more ventrally within the nucleus and with a discrete subset of projection targets. These ps:LC neurons had distinct electrophysiological properties with shorter action potentials and smaller afterhyperpolarizations compared to neurons located in the core of the LC. In vivo recordings of ps:LC neurons showed a lower spontaneous firing frequency than those in the core and they were all excited by noxious stimuli. Using this CAV2-based approach we have demonstrated the ability to retrogradely target, characterise and optogenetically manipulate a central noradrenergic circuit and show that the ps:LC module forms a discrete unit.This article is part of a Special Issue entitled SI: Noradrenergic System

    Jet formation and jet velocity fluctuations in a flue organ pipe

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    Flow visualization of the initial transient in a small recorderlike flue organ pipe is presented and the various stages of the jet formation are related to measurements of the acoustic response of the pipe. An initial acoustic signal, due to the unsteady volume flow of the jet, appears before the forming jet reaches the labium. This signal can easily be modeled using a low-frequency approximation. The initial trajectory of the jet makes a curve towards the exterior of the pipe. Under certain conditions, the jet may even, at first, miss the labium. This effect is related to the steepness of the pressure rise in the foot of the pipe. The initial impact of the jet with the labium appears to be a crucial factor in the triggering of the transient. Moving the labium towards the exterior of the pipe, using a steep pressure rise or putting ears around the mouth increase the chance that the jet will hit the labium. This initial impact is followed by an impulsive vortex shedding at the labium and subsequently a high-frequency varicoselike oscillation is observed on the jet. This oscillation is also observed without labium. After about three periods of the fundamental mode of the pipe, turbulence appears therefore destroying these coherent structures. Whereas the time dependency of the jet velocity dominates the first stage of the starting transient, the jet velocity fluctuations during steady-state result in a non-negligible damping. This loss mechanism is, for the fundamental mode of our experimental organ pipe, of the same order of magnitude as the radiation or visco-thermal damping.</p
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