4,416 research outputs found

    Qubit Reset with a Shortcut-to-Isothermal Scheme

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    Landauer's principle shows that the minimum energy cost to reset a classical bit in a bath with temperature TT is kBTln2k_{B}T\ln2 in the infinite time. However, the task to reset the bit in finite time has posted a new challenge, especially for quantum bit (qubit) where both the operation time and controllability are limited. We design a shortcut-to-isothermal scheme to reset a qubit in finite time τ\tau with limited controllability. The energy cost is minimized with the optimal control scheme with and without nonholonomic constraint. This optimal control scheme can provide a reference to realize qubit reset with minimum energy cost for the limited time.Comment: 8 pages, 7 figure

    Survey of Computational Algorithms for MicroRNA Target Prediction

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    MicroRNAs (miRNAs) are 19 to 25 nucleotides non-coding RNAs known to possess important post-transcriptional regulatory functions. Identifying targeting genes that miRNAs regulate are important for understanding their specific biological functions. Usually, miRNAs down-regulate target genes through binding to the complementary sites in the 3' untranslated region (UTR) of the targets. In part, due to the large number of miRNAs and potential targets, an experimental based prediction design would be extremely laborious and economically unfavorable. However, since the bindings of the animal miRNAs are not a perfect one-to-one match with the complementary sites of their targets, it is difficult to predict targets of animal miRNAs by accessing their alignment to the 3' UTRs of potential targets. Consequently, sophisticated computational approaches for miRNA target prediction are being considered as essential methods in miRNA research

    An Analysis of Information Systems Research in Chinese Mainland

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    This study examines information systems (IS) research in Chinese Mainland in recent years and identifies the similarities and the differences between international and Chinese IS research in terms of research topics and research methods. The data consists of a total of 410 research papers published in ten leading Chinese academic journals related to IS over the five-year period from 1999 to 2004. Compared to IS research abroad, the following may be said of Chinese IS research: (1) Systems-related issues, especially system design issues, system implementation, analytical models and tools, DSS/ESS/EIS are emphasized in research topics, whereas human-related and research methodologies issues are scarce. (2) Empirical studies, including case study, survey and experiment, are few and far between. (3) The majority of non-empirical studies focus on applications and conceptual description of IS, mainly in different applied fields and introducing or illustrating hot topics abroad. The general shift from traditional issues such as system design to non-technical problems is still continuing. There is a need to go beyond mere description of IS related phenomenon and to move away from non-empirical to empirical studies

    Efficiency Enhancement in Polymer Solar Cells With a Polar Small Molecule Both at Interface and in the Bulk Heterojunction Layer

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    The polar molecules, including ferroelectric materials with large dipole moments, have been applied as interfacial layers to increase the efficiency of organic solar cells by increasing the bounded charge separation, tuning the energy levels, etc. Here, we report a small polar molecule 2-cyano-3- (4-(diphenylamino) phenyl)acrylic acid (TPACA) that can be either blended in the active layer or at the polymer/electrode interface to increase the efficiency of organic solar cell devices after poling. It is found that the built-in potential of the device is increased by 0.2 V after poling under negative bias. Blending TPACA into the active layer has shown to be a universal method to increase the efficiency of polymer solar cells. The efficiency is increased by 30–90% for all the polymer:fullerene systems tested, with the highest efficiency reaching 7.83% for the poly[4,8-bis-(2-ethyl-hexyl-thiophene-5-yl)-benzo[1,2-b:4,5-b’]dithiophene-2,6-diyl]-alt-[2-(2’-ethyl-hexanoyl)-thieno[3,4-b]thiophen-4,6-diyl]: [6,6]-phenyl-C71 -butyric acid methyl ester (PBDTTT-CT:PC70BM) system

    Bis(1H-benzimidazole-κN 3)bis­(4-methyl­benzoato-κ2 O,O′)copper(II)

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    In the title mononuclear complex, [Cu(C8H7O2)2(C7H6N2)2], the CuII atom lies on an inversion centre and is coordinated by two O atoms of two monodentate 4-methyl­benzoate ligands and two N atoms of two benzimidazole ligands in a square-planar geometry. The mol­ecules are linked into chains running parallel to the b axis by inter­molecular N—H⋯O hydrogen bonds and by π–π stacking inter­actions [centroid–centroid distance = 3.669 (2) Å] involving centrosymmetrically related imidazole rings

    Seroprevalence and Genetic Characterization of Toxoplasma Gondii in Three Species of Pet Birds in China

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    Background Toxoplasmosis, caused by the protozoan parasite Toxoplasma gondii, is one of the most common zoonosis worldwide, affecting a wide range of warm-blooded mammals and birds worldwide. However, no information on T. gondii infection in pet birds in China is available. Therefore, this study was performed to determine the prevalence of T. gondii infection in pet birds in Gansu province, China. Methods A total of 687 blood samples were collected from pet birds (Carduelis spinus, Alauda gulgula, Cocothraustes migratorlus) in three representative administrative regions in Gansu province, northwest China between August 2011 and September 2012 T. gondii antibodies were determined using the modified agglutination test (MAT). Genomic DNA was extracted from the brain tissues of seropositive pet birds and T. gondii B1 gene was amplified using a semi-nested PCR.DNA samples giving positive B1 amplification were then genetically characterized using multi-locus PCR-RFLP. Results The overall T. gondii seroprevalence was 11.21% (77/687). C. spinus had the highest T. gondii seroprevalence (11.65%), followed by A. arvensis (11.39%) and C. migratorlus (5.26%), these differences were not statistically significant (P \u3e 0.05). Of 77 DNA samples, 8 were positive for the T. gondii B1 gene, four showed complete genotyping results. Only one genotype (the Type II variant: ToxoDB genotype #3) was identified. Conclusions The results of the present survey indicated the presence of T. gondii infection in pet birds in Gansu province, China. These data provide base-line information for the execution of control strategies against T. gondii infection in pet birds. To our knowledge, this is the first report documenting the occurrence of T. gondii prevalence and genotype in pet birds in China
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