253 research outputs found

    DeWitt boundary condition is consistent in Hořava-Lifshitz quantum gravity

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    In quantum cosmology the DeWitt boundary condition is a proposal to set the wave function of the universe to vanish at the classical big-bang singularity. In this Letter, we show that in many gravitational theories including general relativity, the DeWitt wave function does not take a desired form once tensor perturbations around a homogeneous and isotropic closed universe are taken into account: anisotropies and inhomogeneities due to the perturbations are not suppressed near the classical singularity. We then show that Hořava-Lifshitz gravity provides a satisfactory DeWitt wave function. In particular, in the limit of z = 3 anisotropic scaling, we find an exact analytic expression for the DeWitt wave function of the universe with scale-invariant perturbations. In general cases with relevant deformations, we show that the DeWitt wave function can be systematically expanded around the classical big-bang singularity with perturbations under control

    DeWitt wave function in Ho\v{r}ava-Lifshitz cosmology with tensor perturbation

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    We present a well-tempered DeWitt wave function, which vanishes at the classical big-bang singularity, in Ho\v{r}ava-Lifshitz (HL) cosmology with tensor perturbation, both analytically and numerically. In general relativity, the DeWitt wave function is ill-behaved once the tensor perturbation is taken into account. This is essentially because the amplitude of the perturbation diverges at the singularity and the perturbative expansion completely breaks down. On the other hand, in HL gravity it is known that the higher dimensional operators required by the perturbative renormalizability render the tensor perturbation scale-invariant and regular all the way up to the singularity. In this paper we analytically show that in d+1d+1 dimensional HL gravity the DeWitt wave function for tensor perturbation is indeed well-defined around the classical big-bang singularity. Also, we numerically demonstrate the well-behaved DeWitt wave function for tensor perturbation from the big-bang to a finite size of the Universe.Comment: 20 pages, 4 figure

    Architecture of Job scheduling simulator for demand response based resource provisioning

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    We study a new service model based on the Demand Response (DR) resource provisioning at High Performance Computing (HPC) centers. This DR-based resource provisioning model allows administrators of HPC centers to provide computing services with incentives to users to compensate for the performance loss due to power saving operations. In a power conservation mode, a job’s performance may decrease, both in terms of a job waiting time and a job execution time. With DR-based resource provisioning, the submitted jobs are divided into two categories, allowed jobs and disallowed jobs, depending on the user’s tolerance in the performance degradation. The allowed jobs, if indeed affected by the power saving operations, will receive compensation in accordance with an incentive system which determines the reward to the user. For designing an appropriate demand response model, we need to focus on the increase in the job’s execution time and the job’s waiting time, and the corresponding decrease in the power consumption. These are important factors in deriving an incentive system. Currently, no existing approaches can reliably quantify the effectiveness and the contribution of these factors in HPC job scheduling and resource provisioning. In this paper, we propose a newly developed job scheduling simulator that can evaluate DR-based resource provisioning approach under various operating conditions. We designed and implemented the job scheduling simulator for HPC demand-response resource provisioning using a general-purpose discrete-event simulator. Our experiments show that the job scheduling simulator can properly represent the demand response resource provisioning using different job scheduling scenarios

    A 2.75-Approximation Algorithm for the Unconstrained Traveling Tournament Problem

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    A 2.75-approximation algorithm is proposed for the unconstrained traveling tournament problem, which is a variant of the traveling tournament problem. For the unconstrained traveling tournament problem, this is the first proposal of an approximation algorithm with a constant approximation ratio. In addition, the proposed algorithm yields a solution that meets both the no-repeater and mirrored constraints. Computational experiments show that the algorithm generates solutions of good quality.Comment: 12 pages, 1 figur

    Physiological and Biochemical Characterization of Three Nucleoside Diphosphate Kinase Isozymes from Rice (Oryza sativaL.)

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    Nucleoside diphosphate kinase (NDPK) is a ubiquitous enzyme that catalyzes the transfer of the γ-phosphoryl group from a nucleoside triphosphate to a nucleoside diphosphate. In this study, we examined the subcellular localization, tissue-specific gene expression, and enzymatic characteristics of three rice NDPK isozymes (OsNDPK1-OsNDPK3). Sequence comparison of the three OsNDPKs suggested differential subcellular localization. Transient expression of green fluorescence protein-fused proteins in onion cells indicated that OsNDPK2 and OsNDPK3 are localized to plastid and mitochondria respectively, while OsNDPK1 is localized to the cytosol. Expression analysis indicated that all the OsNDPKs are expressed in the leaf, leaf sheath, and immature seeds, except for OsNDPK1, in the leaf sheath. Recombinant OsNDPK2 and OsNDPK3 showed lower optimum pH and higher stability under acidic pH than OsNDPK1. In ATP formation, all the OsNDPKs displayed lower K(m) values for the second substrate, ADP, than for the first substrate, NTP, and showed lowest and highest K(m) values for GTP and CTP respectively

    Omental Abscess after Laparoscopic Proximal Gastrectomy Successfully Treated with Percutaneous Drainage

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    We report the case details of a 65-year-old Japanese man with an omental abscess that was discovered 43 days after he underwent a laparoscopic proximal gastrectomy for gastric cancer. His chief complaint was mild abdominal pain that had persisted for several days. The abscess was diagnosed as a rare postoperative complication. We hesitated to perform a reoperation given the invasiveness of general anesthesia and surgery, plus the possibility of postoperative adhesions and because the patient’s general condition was stable and he had only mild abdominal pain. Percutaneous drainage using a 10.2-F catheter was performed with the patient under conscious sedation and computed tomography–fluoroscopy guidance, with no complications. After the procedure, the size of the abscess cavity was remarkably reduced, and 23 days later the catheter was withdrawn

    Lymphocyte Responses to Chymotrypsin- or Trypsin V-Digested β-Lactoglobulin in Patients with Cow's Milk Allergy

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    <p/> <p>Chymotrypsin- or trypsin V- (a mixture of trypsin and chymotrypsin) digested β-lactoglobulin (BLG) peptides were prepared and were confirmed to have much less immunoglobulin (lg)G and lgE reactivity compared with intact BLG by IgG inhibition enzymelinked immunosorbent assay and IgE dot blotting. The lymphocyte responses to intact BLG and these peptides were examined using peripheral blood mononuclear cells (PBMCs) from 10 patients with cow's milk allergy. The PBMCs from most patients had lower lymphocyte responses to chymotrypsin- and trypsin V-digested BLG peptides than those to intact BLG. However, PBMCs from one and two patients retained significant proliferative responses to both peptides and to only the former peptide, respectively. Interferon-c production stimulated by chymotrypsin-digested peptides was still detectable in all five patients tested. Chymotrypsindigested BLG reduced lgE reactivity but still induced some lymphocyte responses.</p
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