7,429 research outputs found

    Correlation of hippocampal theta rhythm with changes in cutaneous temperature

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    A possible role for the hippocampus in alerting an animal to changes in cutaneous temperature was examined. Following local warming or cooling of the ears of unanesthetized, loosely restrained rabbits, theta waves (4-7 Hz EEG waves) were recorded from electrodes straddling the hippocampus. The onset of the hippocampal theta rhythm was correlated with changes in cutaneous temperature, an observation consistent with studies indicating that the theta rhythm is a nonspecific response evoked by stimulation of several sensory modalities. Additional data from cats and rabbits were correlated with specific neurons within the hippocampus, namely pyramidal cells. Post stimulus time histograms obtained by excitation of the dorsal fornix were interpreted in terms of excitatory and inhibitory inputs to pyramidal cells. Thus, the theta rhythm, which appears to be evoked by changes in cutaneous temperature, can be related to a specific type of hippocampal neuron which is in turn connected with other areas of the brain involved in temperature regulation

    Efficient graphene-based photodetector with two cavities

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    We present an efficient graphene-based photodetector with two Fabri-P\'erot cavities. It is shown that the absorption can reach almost 100% around a given frequency, which is determined by the two-cavity lengths. It is also shown that hysteresis in the absorbance is possible, with the transmittance amplitude of the mirrors working as an external driving field. The role of non-linear contributions to the optical susceptibility of graphene is discussed.Comment: 10 pages, 8 figures. published version: minor revisio

    IR optical fiber-based noncontact pyrometer for drop tube instrumentation

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    The design of a two color pyrometer with infrared optical fiber bundles for collection of the infrared radiation is described. The pyrometer design is engineered to facilitate its use for measurement of the temperature of small, falling samples in a microgravity materials processing experiment using a 100 meter long drop tube. Because the samples are small and move rapidly through the field of view of the pyrometer, the optical power budget of the detection system is severly limited. Strategies for overcoming this limitation are discussed

    Electronic and optical properties in non-uniformly shaped QDashes

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    We theoretically study the optical properties and the electronic structure of highly elongated quantum dots (quantum dashes) and show how carrier trapping due to geometrical fluctuations of the confining potential affects the excitonic spectrum of the system. We focus on the study of the optical properties of a single exciton confined in the structure. The dependence of the absorption and emission intensities on the geometrical properties (depth and position) of the trapping center of a quantum dash is analyzed and the dependence of the degree of linear polarization on these geometrical parameters is studied in detail.Comment: 17 pages, 9 figure

    Sensitivity of Pigment Content of Banana and Orchid Tissue Culture Exposed to Extremely Low Frequency Electromagnetic Fiel

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    Natural exposure of extremely low frequency electromagnetic field (ELF-EMF) occurs in the environment and acts as one of the abiotic factors that affect the growth and development of organisms. This study was conducted to determine the effect of ELF-EMF on the tissue cultured banana and slipper orchid chlorophyll content as one of the indicators in measuring plant photosynthetic capacity. Four days old banana (Musa sp. cv. Berangan) corm and seven days old slipper orchid (Paphiopedilum rothschildianum) cultures were exposed to 6 and 12 mT ELF-EMF generated by controllable ELF-EMF built up machine for 0.5, 1, 2 and 4 hours. After exposure, the banana and orchid cultures were incubated at 25° C for 8 and 16 weeks, respectively. The results showed that the ELF-EMF exposure had different effects on banana and slipper orchid cultures though both plant species belong to monocotyledon. The highest increase in chlorophyll content on banana was resulted by the high intensity and long duration of ELF-EMF exposure (12 mT for 4 hours), whereas on slipper orchid the modest and short duration of ELF-EMF exposure produced the most excessive chlorophyll content. Different ELF-EMF exposures (12 mT for 4 hours and 6 mT for 30 minutes) had potential to be applied on each plant to improve in vitro plant (banana and slipper orchid, respectively) growth. The increased chlorophyll and carotene/xanthophyll content on banana indicated that the banana was more tolerant to ELF-EMF exposure compared to slipper orchid

    Adaptive Processing of Spatial-Keyword Data Over a Distributed Streaming Cluster

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    The widespread use of GPS-enabled smartphones along with the popularity of micro-blogging and social networking applications, e.g., Twitter and Facebook, has resulted in the generation of huge streams of geo-tagged textual data. Many applications require real-time processing of these streams. For example, location-based e-coupon and ad-targeting systems enable advertisers to register millions of ads to millions of users. The number of users is typically very high and they are continuously moving, and the ads change frequently as well. Hence sending the right ad to the matching users is very challenging. Existing streaming systems are either centralized or are not spatial-keyword aware, and cannot efficiently support the processing of rapidly arriving spatial-keyword data streams. This paper presents Tornado, a distributed spatial-keyword stream processing system. Tornado features routing units to fairly distribute the workload, and furthermore, co-locate the data objects and the corresponding queries at the same processing units. The routing units use the Augmented-Grid, a novel structure that is equipped with an efficient search algorithm for distributing the data objects and queries. Tornado uses evaluators to process the data objects against the queries. The routing units minimize the redundant communication by not sending data updates for processing when these updates do not match any query. By applying dynamically evaluated cost formulae that continuously represent the processing overhead at each evaluator, Tornado is adaptive to changes in the workload. Extensive experimental evaluation using spatio-textual range queries over real Twitter data indicates that Tornado outperforms the non-spatio-textually aware approaches by up to two orders of magnitude in terms of the overall system throughput

    ANALISIS PEMBAKARAN DAN PEMANASAN PADA KOMPOR BIJI JARAK DENGAN BERBAGAI DIAMETER DAN JUMLAH

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    Theobjective of this research was to analyze burning and heating on the stove ofjatropha-seeds with various of diameters and sarangan holes, in order to achieve the higher efficiency of the stoveof jatropha-seeds.  Thisresearch has been conducted in the machinery and workshop laboratory of TheAgricultural Engineering Program, The Agricultural Technology Department,Agriculture Faculty, Sriwijaya University, Indralaya from April 2011 to October2011.  Themethod which is used in this research is block randomized design factorialmethod which consist of two treatment factors and each treatment factor consistof two stages and each treatment combination is repeated three times. The firsttreatment with two stages is the diameter of the sarangan holes (3 mm and 4mm), the second treatment with two stages is the amount of the sarangan holesper cm2 (2 pieces/cm2 and 4 pieces/cm2).  The parameter observed include the mainparameters and the supporting parameter. The main parameter is the fuel combustion rate, flame height ,efficiencyof water heating, the rate of water heating, and the supporting parameter includingflame temperature, fuel efficiency, burning time of the jatropha fuels, waterheating time, the difference temperature on the components of the stove.  The research result showed the best that sarangancontained on D1X1 with a combination of diameter (3 mm)and the amount of sarangan holes per-cm2 (2 pieces/cm2)with 0,69 kg/jam of combustion rate, 30 cm of flame height, the rate of waterheating 0,1245kkal/s, and the efficiency of waterheating 8,86 %. Keywords :The jatropha-seeds stove, Jatropha-seed fuels, and Sarangan of the jatropha-seedsstov
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