Direction-sensitive dark matter search results in a surface laboratory

We developed a three-dimensional gaseous tracking device and performed a direction-sensitive dark matter search in a surface laboratory. By using 150 Torr carbon-tetrafluoride (CF_4 gas), we obtained a sky map drawn with the recoil directions of the carbon and fluorine nuclei, and set the first limit on the spin-dependent WIMP (Weakly Interacting Massive Particles)-proton cross section by a direction-sensitive method. Thus, we showed that a WIMP-search experiment with a gaseous tracking device can actually set limits. Furthermore, we demonstrated that this method will potentially play a certain role in revealing the nature of dark matter when a low-background large-volume detector is developed.Comment: 9 figures, accepted for publication in Phys. Lett.

Performance of a Time-Projection-Chamber with a Large-Area Micro-Pixel-Chamber Readout

A micro time-projection-chamber (micro-TPC) with a detection volume of 23*28*31 cm^3 was developed, and its fundamental performance was examined. The micro-TPC consists of a micro pixel chamber with a detection area of 31*31 cm^2 as a two-dimensional imaging device and a gas electron multiplier with an effective area of 23*28 cm^2 as a pre-gas-multiplier. The micro-TPC was operated at a gas gain of 50,000, and energy resolutions and spatial resolutions were measured.Comment: 4 pages, 7 figures, proceedings of IWORID

First underground results with NEWAGE-0.3a direction-sensitive dark matter detector

A direction-sensitive dark matter search experiment at Kamioka underground laboratory with the NEWAGE-0.3a detector was performed. The NEWAGE- 0.3a detector is a gaseous micro-time-projection chamber filled with CF4 gas at 152 Torr. The fiducial volume and target mass are 20*25*31 cm3 and 0.0115 kg, respectively. With an exposure of 0.524 kgdays, improved spin-dependent weakly interacting massive particle (WIMP)-proton cross section limits by a direction-sensitive method were achieved including a new record of 5400 pb for 150 GeV/c2 WIMPs. We studied the remaining background and found that ambient gamma-rays contributed about one-fifth of the remaining background and radioactive contaminants inside the gas chamber contributed the rest.Comment: 21 pages, 8 figures, to appear in Physics Letters

Relationship between milking management practices and milk somatic cell counts on local dairy farms

推奨されている搾乳衛生が体細胞数に及ぼす影響を知るために、北海道十勝地方の1373戸の酪農家を対象に調査を行った。調査方法は、客観的に評価できる項目を獣医師による聞き取り調査で、また客観的に評価困難な項目については乳検検定時に検定員により調査した。統計学的分析はt検定、一元配置分散分析、多変量解析数量化I類を用いて行った。体細胞数に最も影響度の高かった搾乳衛生は、牛体清潔度、乾乳期治療の有無、ポストディッピングの実施時期、過搾乳の有無、ディッパーの種類、搾乳手袋装着の有無、乳房炎軟膏の注入の仕方であった。また、この7つの作業を影響度の高い作業から順に加えて同時実施していくと、平均バルク乳体細胞数（log（X/10^3））は2.21から2.14へ減少し、同時実施しない作業を増やしていくと2.31から2.45へ増加した。同様に影響度の高い作業から順に同時実施していくと、平均体細胞リニアスコアは2.65から2.36に減少し、同時実施しない作業を増やしていくと2.96から3.76に増加した。以上のことから、現在推奨されている搾乳衛生は、体細胞数を低減する上で重要であることが確認できた。また、体細胞数に相関が高い作業の同時実施により体細胞数の低減効果が高いことが明らかになったことから、これらの作業を含めた推奨作業の同時実施が重要であり、特に相関の高かった作業の確実な実施を指導する必要があると考えられた

Contactless Vital Signs Measurement System Using RGB-Thermal Image Sensors and Its Clinical Screening Test on Patients with Seasonal Influenza

Background: In the last two decades, infrared thermography (IRT) has been applied in quarantine stations for the screening of patients with suspected infectious disease. However, the fever-based screening procedure employing IRT suffers from low sensitivity, because monitoring body temperature alone is insufficient for detecting infected patients. To overcome the drawbacks of fever-based screening, this study aims to develop and evaluate a multiple vital sign (i.e., body temperature, heart rate and respiration rate) measurement system using RGB-thermal image sensors. Methods: The RGB camera measures blood volume pulse (BVP) through variations in the light absorption from human facial areas. IRT is used to estimate the respiration rate by measuring the change in temperature near the nostrils or mouth accompanying respiration. To enable a stable and reliable system, the following image and signal processing methods were proposed and implemented: (1) an RGB-thermal image fusion approach to achieve highly reliable facial region-of-interest tracking, (2) a heart rate estimation method including a tapered window for reducing noise caused by the face tracker, reconstruction of a BVP signal with three RGB channels to optimize a linear function, thereby improving the signal-to-noise ratio and multiple signal classification (MUSIC) algorithm for estimating the pseudo-spectrum from limited time-domain BVP signals within 15 s and (3) a respiration rate estimation method implementing nasal or oral breathing signal selection based on signal quality index for stable measurement and MUSIC algorithm for rapid measurement. We tested the system on 22 healthy subjects and 28 patients with seasonal influenza, using the support vector machine (SVM) classification method. Results: The body temperature, heart rate and respiration rate measured in a non-contact manner were highly similarity to those measured via contact-type reference devices (i.e., thermometer, ECG and respiration belt), with Pearson correlation coefficients of 0.71, 0.87 and 0.87, respectively. Moreover, the optimized SVM model with three vital signs yielded sensitivity and specificity values of 85.7% and 90.1%, respectively. Conclusion: For contactless vital sign measurement, the system achieved a performance similar to that of the reference devices. The multiple vital sign-based screening achieved higher sensitivity than fever-based screening. Thus, this system represents a promising alternative for further quarantine procedures to prevent the spread of infectious diseases