1,714 research outputs found

    mproved prediction of properties of π-conjugated oligomers with range-separated hybrid density functionals

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    Cataloged from PDF version of article.Range-separated hybrid functionals along with global hybrids and pure density functionals have been employed to calculate geometries, ionization energies (IP)s, electron affinities (EA)s, and excitation energies of neutral and oxidized polyenes, thiophene, and furan oligomers. Long-range correction with 100% HF exchange solves the problem of density functional theory with incorrect chain length dependence of IPs and energy gaps. There is a possibility of overcorrection, if the short-range part of the functional with no or low HF exchange is too small. The wB97XD functional with 22% of HF exchange in the short-range and a range-separation parameter of 0.2 seems to be just right for conjugated systems at all chain lengths. The wB97XD functional additionally produces negative orbital energies in very good agreement with IPs and EAs. With correct orbital energies, band gaps correspond to transport gaps (E t) and not to optical gaps (Eg). Et is much larger than Eg in the gas phase, but the difference is significantly smaller in the solid state. The accuracy of the negative orbital energies is good down to about 30 eV so that valence and innervalence PE spectra can be modeled. wB97XD is therefore suitable for calculating band structures of conjugated polymers employing orbital energies. © 2011 American Chemical Society

    An investigation on age, growth and biological characteristics of red mullet (Mullus barbatus ponticus, Essipov, 1927) in the Eastern Black Sea

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    This study was carried out during May 2010 – April 2011 in order to determine various biological properties of red mullet occurring in the Eastern Black Sea region. The average length and weight of 1435 specimens were determined as 13.13 cm and 23.14 g, respectively. Weight-length relationship was determined as W = 0.0088 L3.0338. The age distribution of this population ranged between I and VII. The female constituted of 66.2% whereas male 33.8%. Von Bertalanffy growth equation was, whereas for weight was . The GSI index reached its maximum value in June when relative fecundity was 2529.6 eggs g-1 body weight and the average egg size was 360.9 μm. The fecundity-total length and fecundity-weight relationships were calculated as F= 0.0651 TL5.1297 and F= 338.5W1.5128, respectively

    Rate-Distortion Efficient Piecewise Planar 3D Scene Representation from 2-D Images

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    Cataloged from PDF version of article.In any practical application of the 2-D-to-3-D conversion that involves storage and transmission, representation effi- ciency has an undisputable importance that is not reflected in the attention the topic received. In order to address this problem, a novel algorithm, which yields efficient 3-D representations in the rate distortion sense, is proposed. The algorithm utilizes two views of a scene to build a mesh-based representation incrementally, via adding new vertices, while minimizing a distortion measure. The experimental results indicate that, in scenes that can be approximated by planes, the proposed algorithm is superior to the dense depth map and, in some practical situations, to the block motion vector-based representations in the rate-distortion sense

    Role of Alpha Oscillations During Short Time Memory Task Investigated by Graph Based Partitioning

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    In this study, we investigate the clustering pattern of alpha band (8 Hz - 12 Hz) electroencephalogram (EEG) oscillations obtained from healthy individuals during a short time memory task with 3 different memory loads. The retention period during which subjects were asked to memorize a pattern in a square matrix is analyzed with a graph theoretical approach. The functional coupling among EEG electrodes are quantified via mutual information in the time-frequency plane. A spectral clustering algorithm followed by bootstrapping is used to parcellate memory related circuits and for identifying significant clusters in the brain. The main outcome of the study is that the size of the significant clusters formed by alpha oscillations decreases as the memory load increases. This finding corroborates the active inhibition hypothesis about alpha oscillations

    Utilization of Colemanite waste in Concrete Design

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    Waste material is formed in enormous quantities during the beneficiation of raw ore. These wastes can cause both economic loss and environmental pollution. Thus, in this study, the effect of CW obtained from Eti Mine Establishments Kütahya-Emet Boron Plants on the compressive strength and cylinder splitting tensile strength of concrete and its USAbility as a concrete admixture is investigated. The results found show that utilization of Colemanite Waste is possible when it is used as additive in concrete

    Usefulness of Plasmodium falciparum-specific rapid diagnostic tests for assessment of parasite clearance and detection of recurrent infections after artemisinin-based combination therapy

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    Background: Rapid diagnostic test (RDT) is an important tool for parasite-based malaria diagnosis. High specificity of RDTs to distinguish an active Plasmodium falciparum infection from residual antigens from a previous infection is crucial in endemic areas where residents are repeatedly exposed to malaria. The efficiency of two RDTs based on histidine-rich protein 2 (HRP2) and lactate dehydrogenase (LDH) antigens were studied and compared with two microscopy techniques (Giemsa and acridine orange-stained blood smears) and real-time polymerase chain reaction (PCR) for assessment of initial clearance and detection of recurrent P. falciparum infections after artemisinin-based combination therapy (ACT) in a moderately high endemic area of rural Tanzania. Methods: In this exploratory study 53 children \u3c five years with uncomplicated P. falciparum malaria infection were followed up on nine occasions, i.e., day 1, 2, 3, 7, 14, 21, 28, 35 and 42, after initiation of artemether-lumefantrine treatment. At each visit capillary blood samples was collected for the HRP2 and LDH-based RDTs, Giemsa and acridine orange-stained blood smears for microscopy and real-time PCR. Assessment of clearance times and detection of recurrent P. falciparum infections were done for all diagnostic methods. Results: The median clearance times were 28 (range seven to \u3e42) and seven (two to 14) days for HRP2 and LDH-based RDTs, two (one to seven) and two (one to 14) days for Giemsa and acridine orange-stained blood smear and two (one to 28) days for real-time PCR. RDT specificity against Giemsa-stained blood smear microscopy was 21% for HRP2 on day 14, reaching 87% on day 42, and ≥96% from day 14 to 42 for LDH. There was no significant correlation between parasite density at enrolment and duration of HRP2 positivity (r = 0.13, p = 0.34). Recurrent malaria infections occurred in ten (19%) children. The HRP2 and LDH-based RDTs did not detect eight and two of the recurrent infections, respectively. Conclusion: The LDH-based RDT was superior to HRP2-based for monitoring of treatment outcome and detection of recurrent infections after ACT in this moderately high transmission setting. The results may have implications for the choice of RDT devices in similar transmission settings for improved malaria case management. Trial registration. Clinicaltrials.gov, NCT01843764. © 2013 Aydin-Schmidt et al.; licensee BioMed Central Ltd
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