Neutrino spectral density at electroweak scale temperature

Motivated by the scenario of resonant leptogenesis in which lepton number creation in the electroweak-scale is relevant, we investigate the spectral properties and possible collective nature of the standard model neutrinos at electroweak scale temperature (T). We adopt the R_xi gauge fixing, which includes the unitary gauge as a limiting case, and allows us to study the broken as well as the restored phases of the gauge symmetry in a unified way. We show that the spectral density of the neutrino has a three-peak structure in the low-momentum region due to the scattering with the thermally excited particles (i.e., Landau damping) when T becomes comparable to the weak-boson masses in the plasma. The three peaks are identified with a novel ultrasoft mode, the usual quasiparticle, and antiplasmino modes. Varying the gauge-fixing parameter, we show that the three-peak structure appears independently of the gauge fixing and thus has a physical significance. We discuss possible implications of the neutrino spectral density obtained in the present work on particle cosmology, in particular in the context of resonant leptogenesis.Comment: 17 pages, 12 figure

Development of an Electromagnetic Wave Shielding Textile by Electroless Ni-Based Alloy Plating

A polyester nonwoven textile with Ni-based alloy coating was fabricated, and the effect of electromagnetic wave shielding was evaluated. The Ni-based was coated by electroless plating on the textile. The electromagnetic wave shielding effect of the textile with Ni-B coating was about 99.98% over the induction range of 6-13 GHz. Because the textile has thin, light, flexible, and breathable characteristics, it will be versatile for the various electromagnetic wave shielding applications.ArticleIEEE TRANSACTIONS ON MAGNETICS. 45(10):4173-4175 (2009)journal articl

Cross-Talk Suppression in High-Density Printed Circuit Boards Using Magnetic Composite Filled in Spacing Between Signal Lines

Recently, high-density printed circuit boards (HD-PCBs) with less than 50 mum/50 mum line/space has been developed. In the HD-PCB, since the spacing between adjacent signal lines becomes very small, the crosstalk electromagnetic interference among adjacent lines becomes serious. In general, in order to suppress the crosstalk, the ground line is located at the spacing between signal lines because of the decrease of mutual capacitance among adjacent signal lines. The authors have proposed a magnetic method for reducing the crosstalk. The composite magnetic material was filled in the spacing between signal lines instead of the ground line. The magnetic composite is composed of Fe-Si-B-Cr amorphous particles with a mean diameter of 6 mu m and epoxy resin. From the experiments using the PCB-TEG with a 130 mum/50 mum line/space and 25-mm line length, the crosstalk was suppressed in the wide frequency range by using the magnetic composite. In the case of using 51 vol.% amorphous composite, the crosstalk suppression was up to 20 dB around 1 GHz. The influence of the magnetic composite on the transmission and reflection in the main signal line was very small. Therefore, the proposed method is effective for crosstalk suppression without influence on the signal transmission.ArticleIEEE TRANSACTIONS ON MAGNETICS. 45(10):4801-4803 (2009)journal articl

Interweaving Chiral Spirals

We elaborate how to construct interweaving chiral spirals in (2+1) dimensions, defined as a superposition of chiral spirals oriented in different directions. We divide a two-dimensional Fermi sea into distinct wedges, characterized by the opening angle 2Theta and depth Q ~ pF, where pF is the Fermi momentum. In each wedge, the energy is lowered by forming a single chiral spiral. The optimal values for Theta and Q are chosen by balancing this gain in energy versus the cost of deforming the Fermi surface (which dominates at large Theta) and patch-patch interactions (dominant at small Theta). Using a non-local four-Fermi interaction model, we estimate the gain and cost in energy by expanding in terms of 1/Nc (where Nc is the number of colors), lqcd/Q, and Theta. Due to a form factor in our non-local model, at small 1/Nc the mass gap (chiral condensate) is large, and the interaction among quarks and the condensate local in momentum space. Consequently, interactions between different patches are localized near their boundaries, and it is simple to embed many chiral spirals. We identify the dominant and subdominant terms at high density and categorize formulate an expansion in terms of lqcd/Q or Theta. The kinetic term in the transverse directions is subdominant, so that techniques from (1+1)-dimensional systems can be utilized. To leading order in 1/Nc and lqcd/Q, the total gain in energy is ~ pF lqcd^2 with Theta ~ (lqcd/pF)^{3/5}. Since Theta decreases with increasing pF, there should be phase transitions associated with the change in the wedge number. We also argue the effects of subdominant terms at lower density where the large-Nc approximation is more reliable.Comment: 54 pages, 21 figures, published versio

4-Phenyl­diazenyl-2-[(R)-(1-phenyl­ethyl)imino­meth­yl]phenol

The title chiral photochromic Schiff base compound, C21H19N3O, was synthesized from (R)-1-phenyl­ethyl­amine and the salicylaldehyde of an azobenzene derivative. The mol­ecule corresponds to the phenol–imine tautomer, the C=N and N—C bond distances being 1.279 (3) and 1.477 (3) Å, respectively. An intra­molecular O—H⋯N hydrogen bond occurs. The diazenyl group adopts a trans form with an N=N distance of 1.243 (3) Å

Advanced Treatment and Imaging in Colonoscopy: The Pocket-Creation Method for Complete Resection and Linked Color Imaging for Better Detection of Early Neoplastic Lesions by Colonoscopy

Early detection and resection of neoplastic lesions are key objectives to diminish colorectal cancer mortality. Resection of superficial colorectal neoplasms, cold snare polypectomy, endoscopic mucosal resection, and endoscopic submucosal dissection have all been developed and used worldwide. The pocket-creation method facilitates the resection of tumors in difficult and routine locations. Early detection is the most important first step to maximize the benefits of recent advancements in endoscopic techniques. However, the detection of small, flat-shaped, or faded color lesions remains difficult. Linked color imaging, a novel multi-light technology, facilitates the recognition of minor differences in tissue by enhancing the color contrast between early colorectal neoplasms and surrounding normal mucosa in a bright field of view. The most striking feature of linked color imaging is its ability to display the color of early neoplastic lesions as distinct from inflammatory changes, both of which have similar “redness” when viewed using white light imaging. To increase the detection rate of neoplasms, linked color imaging should be used from the outset for endoscopic observation. Early detection of superficial colorectal tumors can result in decreased mortality from colorectal cancer and maintain a good quality of life for patients

Linked Color Imaging and Blue Laser Imaging for Upper Gastrointestinal Screening

White light imaging (WLI) may not reveal early upper gastrointestinal cancers. Linked color imaging (LCI) produces bright images in the distant view and is performed for the same screening indications as WLI. LCI and blue laser imaging (BLI) provide excellent visibility of gastric cancers in high color contrast with respect to the surrounding tissue. The characteristic purple and green color of metaplasias on LCI and BLI, respectively, serve to increase the contrast while visualizing gastric cancers regardless of a history of Helicobacter pylori eradication. LCI facilitates color-based recognition of early gastric cancers of all morphological types, including flat lesions or those in an H. pylori-negative normal background mucosa as well as the diagnosis of inflamed mucosae including erosions. LCI reveals changes in mucosal color before the appearance of morphological changes in various gastric lesions. BLI is superior to LCI in the detection of early esophageal cancers and abnormal findings of microstructure and microvasculature in close-up views of upper gastrointestinal cancers. Excellent images can also be obtained with transnasal endoscopy. Using a combination of these modalities allows one to obtain images useful for establishing a diagnosis. It is important to observe esophageal cancers (brown) using BLI and gastric cancers (orange) surrounded by intestinal metaplasia (purple) and duodenal cancers (orange) by LCI

Blue Laser Imaging with a Small-Caliber Endoscope Facilitates Detection of Early Gastric Cancer

Conventional endoscopy often misses early gastric cancers with minimal red discoloration because they cannot be distinguished from inflamed mucosa. We treated a patient with a small early gastric cancer that was difficult to diagnose using conventional endoscopy. Conventional endoscopy using a small-caliber endoscope showed only subtle red discoloration of the gastric mucosa. However, blue laser imaging showed a clearly discolored area measuring 10 mm in diameter around the red lesion, which was distinct from the surrounding inflamed mucosa. Irregular vessels on the tumor surface (suspicious for early gastric cancer) were observed even with small-caliber endoscopy. Biopsy revealed a well-moderately differentiated tubular adenocarcinoma, and endoscopic submucosal dissection was performed. Histopathological examination of the specimen confirmed well-moderately differentiated adenocarcinoma localized to the mucosa with slight depression compared to the surrounding mucosa, consistent with the endoscopic findings. This small early gastric cancer became clearly visible with blue laser imaging using small-caliber endoscopy

小笠原諸島におけるムニンカケザトウムシの形態学的および遺伝学的研究

To clarify the morphological and phylogenetic differentiation of Bandona boninensis Suzuki 1974 in Chichi-jima Island of the Bonin (Ogasawara) group of Islands, we studied the external morphological characters and performed sequencing of the cytochrome c oxidase subunit I (COI) gene of mitochondrial DNA (mtDNA) and 28S rRNA of nuclear DNA (nrDNA). The sequences of COI and 28S rRNA were identical among the individuals of B. boninensis. These results suggest that B. boninensis experienced a rapid expansion of its distribution in Chichi-jima Island without undergoing any morphological and molecular differentiation.著者らは小笠原諸島の父島に生息するムニンカケザトウムシBandona boninensis の形態的および系統的分化を明らかにするために、父島の4 地点から採集を行い、体長、触肢腿節の長さ、背甲長および背甲幅、鋏角長、第1～4 脚の腿節長といった形態計測を実施し、ミトコンドリアDNA のCOI 領域および核DNA の28SrRNA 領域に基づく系統樹を作成した。その結果, ムニンカケザトウムシのCOI および28S において塩基置換は見られなかった。この結果は、ムニンカケザトウムシが父島内で系統的分化をほぼ起こしていないことを示す。また、採集を行った個体がすべて雌個体であったことから、これまでの報告の通り、父島においては単為生殖種として生息している可能性が高い