Tight bound on coherent-state-based entanglement generation over lossy channels

The first stage of the hybrid quantum repeaters is entanglement generation based on transmission of pulses in coherent states over a lossy channel. Protocols to make entanglement with only one type of error are favorable for rendering subsequent entanglement distillation efficient. Here we provide the tight upper bound on performances of these protocols that is determined only by the channel loss. In addition, we show that this bound is achievable by utilizing a proposed protocol [arXiv:0811.3100] composed of a simple combination of linear optical elements and photon-number-resolving detectors.Comment: 12 pages, 3 figure

Chaos in Static Axisymmetric Spacetimes I : Vacuum Case

We study the motion of test particle in static axisymmetric vacuum spacetimes and discuss two criteria for strong chaos to occur: (1) a local instability measured by the Weyl curvature, and (2) a tangle of a homoclinic orbit, which is closely related to an unstable periodic orbit in general relativity. We analyze several static axisymmetric spacetimes and find that the first criterion is a sufficient condition for chaos, at least qualitatively. Although some test particles which do not satisfy the first criterion show chaotic behavior in some spacetimes, these can be accounted for the second criterion.Comment: More comments for the quantitative estimation of chaos are added, and some inappropriate terms are changed. This will appear on Class. Quant. Gra

Striatal N-Acetylaspartate Synthetase Shati/Nat8l Regulates Depression-Like Behaviors via mGluR3-Mediated Serotonergic Suppression in Mice

Background: Several clinical studies have suggested that N-acetylaspartate and N-acetylaspartylglutamate levels in the human brain are associated with various psychiatric disorders, including major depressive disorder. We have previously identified Shati/Nat8l, an N-acetyltransferase, in the brain using an animal model of psychosis. Shati/Nat8l synthesizes N-acetylaspartate from L-aspartate and acetyl-coenzyme A. Further, N-acetylaspartate is converted into N-acetylaspartylglutamate, a neurotransmitter for metabotropic glutamate receptor 3.Methods: Because Shati/Nat8l mRNA levels were increased in the dorsal striatum of mice following the exposure to forced swimming stress, Shati/Nat8l was overexpressed in mice by the microinjection of adeno-associated virus vectors containing Shati/Nat8l gene into the dorsal striatum (dS-Shati/Nat8l mice). The dS-Shati/Nat8l mice were further assessed using behavioral and neurochemical tests.Results: The dS-Shati/Nat8l mice exhibited behavioral despair in the forced swimming and tail suspension tests and social withdrawal in the 3-chamber social interaction test. These depression-like behaviors were attenuated by the administration of a metabotropic glutamate receptor 2/3 antagonist and a selective serotonin reuptake inhibitor. Furthermore, the metabolism of N-acetylaspartate to N-acetylaspartylglutamate was decreased in the dorsal striatum of the dS-Shati/Nat8l mice. This finding corresponded with the increased expression of glutamate carboxypeptidase II, an enzyme that metabolizes Nacetylaspartylglutamate present in the extracellular space. Extracellular serotonin levels were lower in the dorsal striatum of the dS-Shati/Nat8l and normal mice that were repeatedly administered a selective glutamate carboxypeptidase II inhibitor.Conclusions: Our findings indicate that the striatal expression of N-acetylaspartate synthetase Shati/Nat8l plays a role in major depressive disorder via the metabotropic glutamate receptor 3-mediated functional control of the serotonergic neuronal system

Giant thymoma successfully resected via median sternotomy and anterolateral thoracotomy: a case report

Abstract Background Some patients with thymoma present with a very large mass in the thoracic cavity. Although the most effective treatment for thymoma is surgical resection, it is difficult to perform because of the size of the tumor and the infiltration of tumor into the surrounding organs and vessels. We report a patient with a giant thymoma that was completely resected via a median sternotomy and left anterolateral thoracotomy. Case presentation A 63-year-old woman presented with a mass in the left thoracic cavity that was incidentally found on a chest X-ray. Chest computed tomography revealed a giant mass (16 × 10 cm) touching the chest wall and diaphragm and pressed against the heart and left upper pulmonary lobe. Complete resection was performed via a median sternotomy and left anterolateral thoracotomy. The tumor was histologically diagnosed as a WHO type B2 thymoma, Masaoka stage II. Conclusions Giant thymomas tend to grow expansively without invasion into surrounding organs and vessels. Surgical resection that employs an adequate approach must be considered, regardless of the size of the tumor

Correlative Factors of Severity of Air Bubbles in the Large Intestine during Colonoscopy

Objectives The condition of air bubbles in the large intestine is an influential factor for good quality of colonoscopy. However, the correlative factors of severity of air bubbles during colonoscopy in the large intestine are not established. Therefore, this study aimed to elucidate the correlative factors influencing the severity of air bubbles in the large intestine