Magnetic Phase Transition and Magnetization Plateau in Cs2_2CuBr4_4

The crystal structure of Cs$_2$CuBr$_4$ is the same as that of Cs$_2$CuCl$_4$, which has been characterized as a spin-1/2 quasi-two-dimensional frustrated system. The magnetic properties of Cs$_2$CuBr$_4$ were investigated by magnetization and specific heat measurements. The phase transition at zero magnetic field was detected at $T_{\rm N}=1.4$ K. It was observed that the magnetization curve has a plateau at about one-third of the saturation magnetization for magnetic field $H$ parallel to the $b$- and $c$-axes, while no plateau was observed for $H\parallel a$. The field-induced phase transition to the plateau state appears to be of the first order. The mechanism leading to the magnetization plateau is discussed.Comment: 6 pages, 4 figures, 4 eps files, ptptex, will appear in Supplement of Progress in Theoretical Physic

Study on behavioral characteristics of wild and hatchery-reared red tilefish

Organized by Graduate School of Informatics, Kyoto University ; JSPS Bangkok Liaison Office ; Japanese Society of Bio-logging Science ; Informatics Research Center for Development of Knowledge Society InfrastructureDecember 13-15, 2004, Imperial Tara Hotel, Bangkok, ThailandThe diel activity of red tilefish Branchiostegus japonicus was studied using two different methods : analysis of biotelemetry records and video observation. We have acquired the biotelemetry tracking records of the red tilefish which were released in Maizuru Bay and tracked from January 2003 to February 2004. The records ware compared to the time of sunrise and sunset, the duration of sunshine, and the lunar cycle, which may influence on light conditions. Whilst the fish showed diel activity, the fish changed their behaviors along with the time of sunrise and sunset; the fish probably moved out of their burrows in the daytime and retreated into the burrows at night. We could not find a clear relationship between the behavior and the other two factors. In the laboratory, the behavior of one hatchery-reared individual was recorded by video for five days in the experimental tank where the light condition changed periodically over 24 hours. The fish was more active in the light periods (550 lx) compared to in the dark periods (0 lx). Since the results from the two methods probably compliment one another, further experiments using the two methods will reveal the detailed behavior of red tilefish

Violation of Kohler's Rule in the Magnetoresistance near the Lower Charge-Density-Wave Instability in NbSe 3

This paper reports the measurements of resistance (R) and magnetoresistance of NbSe 3 near the critical pressure (P c ¼ 7:5 kbar), where the lower charge-density-wave (CDW) phase is on the verge of destruction. For P ¼ 7:6 kbar, the temperature dependence of dR=dT exhibits a weak anomaly at T Ã ¼ 15 K and the superconducting transition is observed at T c ¼ 2:8 K. From the observation of a large magnetoresistance due to an imperfect nesting of Fermi surface, we show that the weak anomaly is closely related to the lower CDW phase. Moreover, an excess conductance and violation of Kohler's rule are found below $T Ã . The origins of the excess conductance and the violation of Kohler's rule are discussed in terms of charge fluctuation associated with the lower CDW state

Improved accuracy in high-frequency AC transport measurements in pulsed high magnetic fields

We show theoretically and experimentally that accurate transport measurements are possible even within the short time provided by pulsed magnetic fields. For this purpose, a new method has been devised, which removes the noise component of a specific frequency from the signal by taking a linear combination of the results of numerical phase detection using multiple integer periods. We also established a method to unambiguously determine the phase rotation angle in AC transport measurements using a frequency range of tens of kilohertz. We revealed that the dominant noise in low-frequency transport measurements in pulsed magnetic fields is the electromagnetic induction caused by mechanical vibrations of wire loops in inhomogeneous magnetic fields. These results strongly suggest that accurate transport measurements in short-pulsed magnets are possible when mechanical vibrations are well suppressed

DOCK2 is involved in the host genetics and biology of severe COVID-19

「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target

The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force

「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection

Finite Temperature Study of the Metamagnetic Transition in Strongly Correlated Laves Phase Intermetallic Compounds(Magnetism)

Finite temperature behavior of itinerant electron metamagnetism is studied on nearly ferromagnetic Laves phase intermetallic compounds Y(Co_Al_x)_2, (0.08≤x≤0.11), in steady fields up to 230kOe. The critical field H_c and the moment value are found to vary with temperature systematically. Thermodynamical consideration of the result has revealed a significant change in the electronic state, with roughly 25?30% of the zero field value of the electronic specific heat being lost by the transition

Detection Range and Horizontal Accuracy of a Fine-Scale Positioning Telemetry System at Kaeng Krachan Reservoir, Thailand

March 18-19, 2013We examined the detection range and the accuracy of fine-scale positioning using Vemco Positioning System (VPS) for understanding the habitat use of Mekong giant catfish at Kaeng Krachan reservoir, Thailand. The appropriate distance between receivers and sound pressure of transmitters for the VPS was determined from the detection range test. We deployed 24 receivers at 500 m distance for the VPS positioning. The positioning accuracy was estimated using the stationary transmitters at fixed locations in the VPS array. The positions of the stationary transmitters were measured accurately (< 15 m). These results suggest that the VPS positioning can be useful for investigating fine-scale habitat use of Mekong giant catfish