907 research outputs found

    High-quality quantum point contact in two-dimensional GaAs (311)A hole system

    Full text link
    We studied ballistic transport across a quantum point contact (QPC) defined in a high-quality, GaAs (311)A two-dimensional (2D) hole system using shallow etching and top-gating. The QPC conductance exhibits up to 11 quantized plateaus. The ballistic one-dimensional subbands are tuned by changing the lateral confinement and the Fermi energy of the holes in the QPC. We demonstrate that the positions of the plateaus (in gate-voltage), the source-drain data, and the negative magneto-resistance data can be understood in a simple model that takes into account the variation, with gate bias, of the hole density and the width of the QPC conducting channel

    Preventing effect of vitamin E on oocytes apoptosis in morphinetreated mice

    Get PDF
    Several studies have shown that Morphine Sulfate affects on fertility, embryogenesis and consequent pregnancy loss and ultrastructural alterations of oocytes in animal model. This study was done to determine the effect of morphine sulfate on oocytes apoptosis and preventive role of daily supplementation of Vitamin E on oocytes apoptosis in morphine sulfate -treated mice. Twenty-four NMARI female mice were randomly allocated into four experimental groups. For 15 days, control group received saline (0.2 ml/day by subcutaneous injection), group I Vitamin E (60 mg/kg/day orally), group II Morphine Sulfate (10 mg/kg/day by subcutaneous injection) and group III Morphine Sulfate with Vitamin E (60 mg/kg/day orally). Then, animals were superovulated with PSMG (10 Units) and 10 Unites of HCG. The next day the animals were sacrificed, oocytes were flushed from each fallopian tube. The collected oocytes were subjected to determine apoptosis by Tunnel assay with using Fluorescent Microscope. According to our results, the number of retrieved oocytes were 121, 132, 86 and 114 in control, experimental group I, II and III, respectively. Morphine Sulfate treatment increased apoptosis in oocytes to 17.44% whereas oocytes apoptosis was 4.13% in Controls. Supplementation with Vitamin E in Morphine Sulfate -treated mice reduced the oocytes apoptosis to 7.01%. This study showed that Morphine can increase apoptosis in oocytes and Vitamin E treatment significantly reduces oocytes apoptosis in the Morphine Sulfate -treated mice

    Female rat hippocampal cell density after conditioned place preference

    Get PDF
    The hippocampus is important for learning tasks, such as conditioned place preference (CPP), which is widely used as a model for studying the reinforcing effects of drugs with dependence liability. Long-term opiate use may produce maladaptive plasticity in the brain structures involved in learning and memory, such as the hippocampus. We investigated the phenomenon of conditioning with morphine on the cell density of female rat hippocampus. Forty-eight female Wistar rats weighing on average 200-250 g were used. Rats were distributed into eight groups. Experimental groups received morphine daily (three days) at different doses (2.5, 5, 7.5 mg/kg) and the control-saline group received normal saline (1 ml/kg), and then the CPP test was performed. Three sham groups received only different doses (2.5, 5, 7.5 mg/kg) of morphine without CPP test. Forty-eight hours after behavioural testing animals were decapitated under chloroform anaesthesia and their brains were fixed, and after tissue processing, slices were stained with cresyl violet for neurons and phosphotungstic acid haematoxylin for astrocytes. The maximum response was obtained with 5 mg/kg of morphine. The density of neurons in CA1 and CA3 areas of hippocampus after injection of morphine and CPP was decreased. The number of astrocytes in different areas of hippocampus was increased after injection of morphine and CPP. It seems that the effective dose was 5 mg/kg, as it led to the CPP. We concluded that both injection of morphine and CPP can decrease the density of neurons and also increase the number of astrocytes in the rat hippocampus

    Quantum filter for a non-Markovian single qubit system

    Full text link
    In this paper, a quantum filter for estimating the states of a non-Markovian qubit system is presented in an augmented Markovian system framework including both the qubit system of interest and multi-ancillary systems for representing the internal modes of the non-Markovian environment. The colored noise generated by the multi-ancillary systems disturbs the qubit system via a direct interaction. The resulting non-Markovian dynamics of the qubit is determined by a memory kernel function arising from the dynamics of the ancillary system. In principle, colored noise with arbitrary power spectrum can be generated by a combination of Lorentzian noises. Hence, the quantum filter can be constructed for the qubit disturbed by arbitrary colored noise and the conditional state of the qubit system can be obtained by tracing out the multi-ancillary systems. An illustrative example is given to show the non-Markovian dynamics of the qubit system with Lorentzian noise.Comment: arXiv admin note: text overlap with arXiv:1503.0799

    Quantum filter for a class of non-Markovian quantum systems

    Full text link
    In this paper we present a Markovian representation approach to constructing quantum filters for a class of non-Markovian quantum systems disturbed by Lorenztian noise. An ancillary system is introduced to convert white noise into Lorentzian noise which is injected into a principal system via a direct interaction. The resulting dynamics of the principal system are non-Markovian, which are driven by the Lorentzian noise. By probing the principal system, a quantum filter for the augmented system can be derived from standard theory, where the conditional state of the principal system can be obtained by tracing out the ancillary system. An example is provided to illustrate the non-Markovian dynamics of the principal system.Comment: 8 pages, 7 figure

    Hope for the best, prepare for the worst: barriers to service innovation

    Get PDF
    Purpose Despite the growing scholarly interest in service innovation and its associated benefits for organizations, research into the barriers to developing new services remains scant. In addition, most of these studies have been mainly conducted at the firm level, failing to incorporate macro forces in the industry. To fill this gap, this study aims to investigate major industry trends as well as organizational attributes that affect organizations’ capability in designing innovative services. Design/methodology/approach A qualitative approach was used. In all, 21 semi-structured interviews with senior executives in different banks were conducted to collect data. Data were analyzed through thematic analysis. Findings The results of this study suggest that privatization, technological shortcomings, legislative inefficiencies and deposit orientation instead of market orientation were major industry trends that affect service innovation. Furthermore, ambiguity in knowledge management regimes, silo mentality and the absence of a collaborative organizational culture, growing need to focus on human capital and risk aversion were the main organizational attributes that should be addressed for effective service innovation. Practical implications Service innovation is a strategic asset for organizations. To effectively leverage the benefits, managers should have an end-to-end approach toward the subject. The findings of this study would inform managers of different obstacles in the development of new services from an organizational and industry-wide perspective. Based on the outputs of the interviews and a thorough review of the literature, managerial implications are presented. Originality/value This study is one of the few studies that explores service innovation challenges at both macro and micro levels of analysis, providing a more holistic view of the phenomenon in the context of service organizations

    Correlated errors can lead to better performance of quantum codes

    Full text link
    A formulation for evaluating the performance of quantum error correcting codes for a general error model is presented. In this formulation, the correlation between errors is quantified by a Hamiltonian description of the noise process. We classify correlated errors using the system-bath interaction: local versus nonlocal and two-body versus many-body interactions. In particular, we consider Calderbank-Shor-Steane codes and observe a better performance in the presence of correlated errors depending on the timing of the error recovery. We also find this timing to be an important factor in the design of a coding system for achieving higher fidelities.Comment: 5 pages, 3 figures. Replaced by the published version. Title change

    Spawning season and fecundity of Sepia pharaonis In Bushehr coastal waters (Persian Gulf)

    Get PDF
    Fecundity rate and spawning season for cuttlefish (Sepia pharaonis), a commercially important species in Busheher coastal waters were studied from December 2007 to May 2008. We collected 142 specimens and after their sexuality were 18 males, 3 immatures, 16 first stage pieces, 14 second stage pieces and 91 pieces in third and fourth stages. The assesse d biological characteristics such as: Mantle length, weight of total body, Nidam ental gland, weight of head, weight of ovary and fecundity rate. We recorded 201 .8 plus or minus 6.8mm for mean, 280mm for maximum and 115mm for minimum mantle length. The mean body total weight was 895.8 plus or minus 143g, and the maximum was 2098g, while its mini mum was 241.13g. The mean, maximum and minimum Nidamental gland weight was 41.1 ± 18.6, 126.8, and 0.2g, respectively. For the relationship between mantle length (ML, mm) and fecundity we found the linear regression equation: Fecundity = -6 30.68+5.22ML. The mean, maximum and minimum fecundity rate was 494 plus or minus 131, 1246 and 178, respectively. The results of this study showed spawning season for Sepia pharaonis in the coastal waters of Busheher Province to be from the end of February to the end of June
    • …
    corecore