963 resultados para Neuron spike sorting
Resumo:
Cerebral energy dysfunction has emerged as an important determinant of prognosis following traumatic brain injury (TBI). A number of studies using cerebral microdialysis, positron emission tomography, and jugular bulb oximetry to explore cerebral metabolism in patients with TBI have demonstrated a critical decrease in the availability of the main energy substrate of brain cells (i.e., glucose). Energy dysfunction induces adaptations of cerebral metabolism that include the utilization of alternative energy resources that the brain constitutively has, such as lactate. Two decades of experimental and human investigations have convincingly shown that lactate stands as a major actor of cerebral metabolism. Glutamate-induced activation of glycolysis stimulates lactate production from glucose in astrocytes, with subsequent lactate transfer to neurons (astrocyte-neuron lactate shuttle). Lactate is not only used as an extra energy substrate but also acts as a signaling molecule and regulator of systemic and brain glucose use in the cerebral circulation. In animal models of brain injury (e.g., TBI, stroke), supplementation with exogenous lactate exerts significant neuroprotection. Here, we summarize the main clinical studies showing the pivotal role of lactate and cerebral lactate metabolism after TBI. We also review pilot interventional studies that examined exogenous lactate supplementation in patients with TBI and found hypertonic lactate infusions had several beneficial properties on the injured brain, including decrease of brain edema, improvement of neuroenergetics via a "cerebral glucose-sparing effect," and increase of cerebral blood flow. Hypertonic lactate represents a promising area of therapeutic investigation; however, larger studies are needed to further examine mechanisms of action and impact on outcome.
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Human altruism shaped our evolutionary history and pervades social and political life. There are, however, enormous individual differences in altruism. Some people are almost completely selfish, while others display strong altruism, and the factors behind this heterogeneity are only poorly understood. We examine the neuroanatomical basis of these differences with voxel-based morphometry and show that gray matter (GM) volume in the right temporoparietal junction (TPJ) is strongly associated with both individuals' altruism and the individual-specific conditions under which this brain region is recruited during altruistic decision making. Thus, individual differences in GM volume in TPJ not only translate into individual differences in the general propensity to behave altruistically, but they also create a link between brain structure and brain function by indicating the conditions under which individuals are likely to recruit this region when they face a conflict between altruistic and selfish acts.
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Electricity spot prices have always been a demanding data set for time series analysis, mostly because of the non-storability of electricity. This feature, making electric power unlike the other commodities, causes outstanding price spikes. Moreover, the last several years in financial world seem to show that ’spiky’ behaviour of time series is no longer an exception, but rather a regular phenomenon. The purpose of this paper is to seek patterns and relations within electricity price outliers and verify how they affect the overall statistics of the data. For the study techniques like classical Box-Jenkins approach, series DFT smoothing and GARCH models are used. The results obtained for two geographically different price series show that patterns in outliers’ occurrence are not straightforward. Additionally, there seems to be no rule that would predict the appearance of a spike from volatility, while the reverse effect is quite prominent. It is concluded that spikes cannot be predicted based only on the price series; probably some geographical and meteorological variables need to be included in modeling.
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The optimal design of a heat exchanger system is based on given model parameters together with given standard ranges for machine design variables. The goals set for minimizing the Life Cycle Cost (LCC) function which represents the price of the saved energy, for maximizing the momentary heat recovery output with given constraints satisfied and taking into account the uncertainty in the models were successfully done. Nondominated Sorting Genetic Algorithm II (NSGA-II) for the design optimization of a system is presented and implemented inMatlab environment. Markov ChainMonte Carlo (MCMC) methods are also used to take into account the uncertainty in themodels. Results show that the price of saved energy can be optimized. A wet heat exchanger is found to be more efficient and beneficial than a dry heat exchanger even though its construction is expensive (160 EUR/m2) compared to the construction of a dry heat exchanger (50 EUR/m2). It has been found that the longer lifetime weights higher CAPEX and lower OPEX and vice versa, and the effect of the uncertainty in the models has been identified in a simplified case of minimizing the area of a dry heat exchanger.
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This paper estimates the determinants of productivity differentials across urban areas in Spain. To do so we resort to Spanish Social Security administrative data (MCVL) matched with workers’ fiscal information. We use two-step approach that allows us to control for the confounding effects due to the sorting of more productive workers and more productive firms in bigger cities. Our results indicate that city size is a significant determinant of productivity differentials across Spanish urban areas. We estimate an elasticity of urban agglomeration of 3.3%, which is within the range of values already observed in other countries. We also find that the level of human capital, firm size and the level of industrial specialization also matters in order explain productivity differentials across Spanish cities. Keywords: Agglomeration, wages, productivity, city size. JEL codes: R10, R23, J31
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Background: Insects respond to the spatial and temporal dynamics of a pheromone plume, which implies not only a strong response to"odor on", but also to"odor off". This requires mechanisms geared toward a fast signal termination. Several mechanisms may contribute to signal termination, among which odorant-degrading enzymes. These enzymes putatively play a role in signal dynamics by a rapid inactivation of odorants in the vicinity of the sensory receptors, although direct in vivo experimental evidences are lacking. Here we verified the role of an extracellular carboxylesterase, esterase-6 (Est-6), in the sensory physiological and behavioral dynamics of Drosophila melanogaster response to its pheromone, cis-vaccenyl acetate (cVA). Est-6 was previously linked to post-mating effects in the reproductive system of females. As Est-6 is also known to hydrolyze cVA in vitro and is expressed in the main olfactory organ, the antenna, we tested here its role in olfaction as a putative odorant-degrading enzyme. Results: We first confirm that Est-6 is highly expressed in olfactory sensilla, including cVA-sensitive sensilla, and we show that expression is likely associated with non-neuronal cells. Our electrophysiological approaches show that the dynamics of olfactory receptor neuron (ORN) responses is strongly influenced by Est-6, as in Est-6° null mutants (lacking the Est-6 gene) cVA-sensitive ORN showed increased firing rate and prolonged activity in response to cVA. Est-6° mutant males had a lower threshold of behavioral response to cVA, as revealed by the analysis of two cVAinduced behaviors. In particular, mutant males exhibited a strong decrease of male-male courtship, in association with a delay in courtship initiation. Conclusions: Our study presents evidence that Est-6 plays a role in the physiological and behavioral dynamics of sex pheromone response in Drosophila males and supports a role of Est-6 as an odorant-degrading enzyme (ODE) in male antennae. Our results also expand the role of Est-6 in Drosophila biology, from reproduction to olfaction, and highlight the role of ODEs in insect olfaction. Keywords: carboxylesterase, esterase 6, olfaction, pheromone, signal termination
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We present an overview of the long-term adaptation of hippocampal neurotransmission to cholinergic and GABAergic deafferentation caused by excitotoxic lesion of the medial septum. Two months after septal microinjection of 2.7 nmol a -amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA), a 220% increase of GABA A receptor labelling in the hippo- campal CA3 and the hilus was shown, and also changes in hippocampal neurotransmission characterised by in vivo microdialysis and HPLC. Basal amino acid and purine extra- cellular levels were studied in control and lesioned rats. In vivo effects of 100 m M KCl perfusion and adenosine A 1 receptor blockade with 1,3-dipropyl- 8-cyclopentylxanthine (DPCPX) on their release were also investigated. In lesioned animals GABA, glutamate and glutamine basal levels were decreased and taurine, adenosine and uric acid levels increased. A similar response to KCl infusion occurred in both groups except for GABA and glutamate, which release decreased in lesioned rats. Only in lesioned rats, DPCPX increased GABA basal level and KCl-induced glutamate release, and decreased glutamate turnover. Our results evidence that an excitotoxic septal lesion leads to increased hippocampal GABA A receptors and decreased glutamate neurotransmis- sion. In this situation, a co-ordinated response of hippocampal retaliatory systems takes place to control neuron excitability.
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Today´s organizations must have the ability to react to rapid changes in the market. These rapid changes cause pressure to continuously find new efficient ways to organize work practices. Increased competition requires businesses to become more effective and to pay attention to quality of management and to make people to understand their work's impact on the final result. The fundamentals in continmuois improvement are systematic and agile tackling of indentified individual process constraints and the fact tha nothin finally improves without changes. Successful continuous improvement requires management commitment, education, implementation, measurement, recognition and regeneration. These ingredients form the foundation, both for breakthrough projects and small step ongoing improvement activities. One part of the organization's management system are the quality tools, which provide systematic methodologies for identifying problems, defining their root causes, finding solutions, gathering and sorting of data, supporting decision making and implementing the changes, and many other management tasks. Organizational change management includes processes and tools for managing the people in an organizational level change. These tools include a structured approach, which can be used for effective transition of organizations through change. When combined with the understanding of change management of individuals, these tools provide a framework for managing people in change,
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In this dissertation the main aim was to study the usability of aspen wood in the mechanical wood processes, especially the factors that affect the usability of aspen wood, which is dried at different temperature levels. The problematic of varying temperatures from level to another seem to have significant effects on distortions. According to the studies conducted, many practical solutions for drying of aspen timber can be made. European aspen sawn timber should be dried in relatively narrow widths, short lengths, edged and sawn pith free. The results achieved give an interesting view for the distortions of aspen wood between HT drying and heat treatment. The most significant result is that cupping seems to decrease when increasing temperature level from HT drying to heat treatment phase. The difference is significant. Other very obvious result is that bow and crook are increasing between these two temperature levels, bow significantly. Also the modelling gives a good background for this result since cupping is reduced by higher temperatures. It can also be assumed that these distortions can be affected for example by sorting out the timber used to different moisture levels before drying. This could be a very simple solution for practical purposes. From practical point of view, it was also noted during the drying tests performed that the discoloration seem to be no problem for aspen boards dried in temperatures under 150 °C. Altogether, this dissertation covers many interesting points of view of factors affecting distortions of wood in different temperature stages. Aspen as species in use of mechanical wood industries seems to be a species suitable for component production. According to the results, the best yield from aspen timber can be achieved in industry that can utilize relatively short components of sawn wood. Results achieved give a significant indication about the factors affecting distortions of wood at different temperature stages of drying, especially considering European aspen.
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Surface sediments from the River São Francisco were analyzed to investigate the impact, due to the presence of metals (Cd, Cu, Pb, Zn) in wastes from a metallurgical industry in the city of Três Marias/MG, Brazil. The concentrations and geochemical associations of Pb, Zn and trace metals associated with the minerals employed in zinc production were measured. Sediments close to discharge locations were highly contaminated with Pb (332-512 μg g-1) and Zn (7872-10780 μg g-1), with values decreasing rapidly due to dilution and hydraulic sorting. Evaluation of toxicity according to the Consensus-based Sediment Quality Guidelines indicated for Cd, Pb and Zn a high probability of adverse effects on aquatic biota at these sites.
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A rapid and low cost method to determine Cr(VI) in soils based upon alkaline metal extraction at room temperature is proposed as a semi-quantitative procedure to be performed in the field. A color comparison with standards with contents of Cr(VI) in the range of 10 to 150 mg kg-1 was used throughout. For the different types of soils studied, more than 75% of the fortified soluble Cr(VI) were recovered for all levels of spike tested for both the proposed and standard methods. Recoveries of 83 and 99% were obtained for the proposed and the standard methods, respectively, taking into account the analysis of a heavily contaminated soil sample.
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Raman imaging spectroscopy is a highly useful analytical tool that provides spatial and spectral information on a sample. However, CCD detectors used in dispersive instruments present the drawback of being sensitive to cosmic rays, giving rise to spikes in Raman spectra. Spikes influence variance structures and must be removed prior to the use of multivariate techniques. A new algorithm for correction of spikes in Raman imaging was developed using an approach based on comparison of nearest neighbor pixels. The algorithm showed characteristics including simplicity, rapidity, selectivity and high quality in spike removal from hyperspectral images.
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Sähkö- ja elektroniikka-alan yritykset eivät yleensä kuormita merkittävästi ympäristöä, sillä teollisuudenalan suurimmat ympäristövaikutukset aiheutuvat alihankkijoiden ja komponenttivalmistajien toiminnasta. Yritysten oma toiminta perustuu pitkälti tuotekehitykseen ja tuotteiden loppukokoonpanoon valmiista komponenteista. Syntynyt jäte on tyypillisesti pääosin pakkausjätettä, metalleja, kaatopaikkajätettä ja vähäisessä määrin myös ongelmajätettä. Vähäisen ympäristökuormituksen johdosta yrityksiltä ei yleensä vaadita ympäristölupaa. Diplomityössä laadittiin jätehuoltosuunnitelma elektroniikka-alan yritykselle. Työ suoritettiin Kemppi Oy:n toimeksiannosta Lahdessa. Jätehuoltosuunnitelman noudattaminen parantaa yrityksen julkisuuskuvaa ja tuo kustannussäästöjä. Toimivan suunnitelman laatiminen vaatii kuitenkin aikaa ja muita resursseja. Jätehuollon toimivuus on tarkistettava säännöllisesti, etenkin silloin kun yrityksen toiminnan painopiste muuttuu. Käytännön osuudessa kartoitettiin edellisvuosien jätemäärät ja yrityksen jätehuollon tila. Jätehuoltosuunnitelman laatimiselle oli selkeä tarve, koska jätehuolto perustui osin kirjoittamattomiin sääntöihin ja vanhoihin tottumuksiin. Syntypaikkalajittelua tehostettiin lisäämällä jäteastioita ja -pisteitä jätteiden syntypaikoille. Lajittelua parannettiin myös laatimalla selkeät ohjeet ja kouluttamalla työntekijöitä.
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Wheat (Triticum aestivum L.) blast caused by Pyricularia grisea is a new disease in Brazil and no resistant cultivars are available. The interactions between temperature and wetness durations have been used in many early warning systems. Hence, growth chamber experiments to assess the effect of different temperatures (10, 15, 20, 25, 30 and 35ºC) and the duration of spike-wetness (0, 5, 10, 15, 20, 25, 30, 35 and 40 hours) on the intensity of blast in cultivar BR23 were carried out. Each temperature formed an experiment and the duration of wetness the treatments. The highest blast intensity was observed at 30°C and increased as the duration of the wetting period increased while the lowest occurred at 25°C and 10 hours of spike wetness. Regardless of the temperature, no symptoms occurred when the wetting period was less than 10 hours but at 25°C and a 40 h wetting period blast intensity exceeded 85%. These variations in blast intensity as a function of temperature are explained by a generalized beta model and as a function of the duration of spike wetness by the Gompertz model. Disease intensity was modeled as a function of both temperature and the durations of spike wetness and the resulting equation provided a precise description of the response of P. grisea to temperatures and the durations of spike wetness. This model was used to construct tables that can be used to predict the intensity of P. grisea wheat blast based on the temperatures and the durations of wheat spike wetness obtained in the field.