Seasonal transport variations of the wind-driven ocean circulation in a two-layer planetary geostrophic model with a continental slope

Using a simple two-layer planetary geostrophic model with a continental slope, the observed seasonal variation of the total transport of the Kuroshio is explained qualitatively for the first time in a quite concise way. During the period of weak winds in summer, the total transport is much larger than the nontopographic Sverdrup transport. This is because the joint effect of baroclinicity and bottom relief (so-called JEBAR) drives the barotropic flow with releasing the available potential energy accumulated in winter. In winter, on the other hand, the transport is much smaller than the nontopographic Sverdrup transport. This is mainly due to the topographic beta-effect. In addition to the available potential energy supplied directly by winds, the barotropic flow excited by the strong winds in winter impinges on the bottom slope to induce the baroclinic flow so that the wind-driven barotropic flow is converted into the available potential energy to be released in summer. Thus, the role of JEBAR is to make the total transport of the Kuroshio relatively insensitive to seasonal changes of winds as observed. This mechanism may be called “JEBAR rectification” for simplicity

A computational model of internal representations of chemical gradients in environments for chemotaxis of Caenorhabditis elegans

The small roundworm Caenorhabditis elegans employs two strategies, termed pirouette and weathervane, which are closely related to the internal representation of chemical gradients parallel and perpendicular to the travelling direction, respectively, to perform chemotaxis. These gradients must be calculated from the chemical information obtained at a single point, because the sensory neurons are located close to each other at the nose tip. To formulate the relationship between this sensory input and internal representations of the chemical gradient, this study proposes a simple computational model derived from the directional decomposition of the chemical concentration at the nose tip that can generate internal representations of the chemical gradient. The ability of the computational model was verified by using a chemotaxis simulator that can simulate the body motions of pirouette and weathervane, which confirmed that the computational model enables the conversion of the sensory input and head-bending angles into both types of gradients with high correlations of approximately r > 0.90 (p < 0.01) with the true gradients. In addition, the chemotaxis index of the model was 0.64, which is slightly higher than that in the actual animal (0.57). In addition, simulation using a connectome-based neural network model confirmed that the proposed computational model is implementable in the actual network structure.This work was supported by JSPS KAKENHI Grant Number 15H03950 to T.T and MEXT KAKENHI Grant Numbers 20115010 to T.T. and 20115002 to Y.I

Suzaku Discovery of a Hard X-Ray Tail in the Persistent Spectra from the Magnetar 1E 1547.0-5408 during its 2009 Activity

The fastest-rotating magnetar 1E 1547.0-5408 was observed in broad-band X-rays with Suzaku for 33 ks on 2009 January 28-29, 7 days after the onset of its latest bursting activity. After removing burst events, the absorption-uncorrected 2-10 keV flux of the persistent emission was measured with the XIS as 5.7e-11 ergs cm-2 s-1, which is 1-2 orders of magnitude higher than was measured in 2006 and 2007 when the source was less active. The persistent emission was also detected significantly with the HXD in >10 keV up to at least ~110 keV, with an even higher flux of 1.3e-10 ergs cm-2 s-1 in 20-100 keV. The pulsation was detected at least up to 70 keV at a period of 2.072135+/-0.00005 s, with a deeper modulation than was measured in a fainter state. The phase-averaged 0.7-114 keV spectrum was reproduced by an absorbed blackbody emission with a temperature of 0.65+/-0.02 keV, plus a hard power-law with a photon index of ~1.5. At a distance of 9 kpc, the bolometric luminosity of the blackbody and the 2-100 keV luminosity of the hard power-law are estimated as (6.2+/-1.2)e+35 ergs s-1 and 1.9e+36 ergs s-1, respectively, while the blackbody radius becomes ~5 km. Although the source had not been detected significantly in hard X-rays during the past fainter states, a comparison of the present and past spectra in energies below 10 keV suggests that the hard component is more enhanced than the soft X-ray component during the persistent activity.Comment: 12 pages, 7 figures, PASJ Vol.62 No.2 accepte

陸棲ラン藻における極限的な乾燥耐性の分子機構

陸棲ラン藻Nostoc communen(和名:イシクラゲ)が示す極限的な乾燥耐性の分子機構を解明するために、本研究課題では細胞内で働いている要素に着目して研究した。本研究経費によってエバポレイティブ光散乱検出器を導入することのよってトレハロースを定量できるようにした。乾燥したイシクラゲはトレハロースを蓄積していたが、吸水することによってトレハロース量は低下し、完全に水和したコロニーでは検出されなかった。コロニーの水分含量に応答してトレハロース量が調節されていることを示す。乾燥ストレスによってトレハロースが蓄積される機構を明らかにするために、トレハロース合成酵素およびトレハロース加水分解酵素(トレハラーゼ)の活性制御を解析した。イシクラゲにおいてトレハロース合成酵素遺伝子treZ、treY、およびトレハラーゼ遺伝子treHがひとつの転写単位を構成していた。これらの遺伝子の転写産物量は乾燥ストレス処理によって大きく変化することはなく、転写レベルの制御ではないことが示された。生化学的解析を行なったところ、トレハロース合成酵素は反応溶液中の塩濃度に影響されず高い活性を示したが、トレハラーゼは塩濃度の上昇に伴って活性が阻害されることが分かった。トレハラーゼがトレハロース量の調節において鍵酵素として働いており、乾燥ストレス下で活性が阻害され、トレハロースの合成量が相対的に高くなることが重要であることを示唆する。細胞外基質に存在する可溶性タンパク質を解析した。β-グルコシダーゼを精製しアミノ末端配列解析を行なったところ、ファシクリンタンパク質と相同性を示すことが分かった。イシクラゲに特徴的なタンパク質として知られているWspAを精製し酵素活性を調べたところβ-ガラクトシダーゼ活性を示すことが分かった。これらのタンパク質は細胞外基質において重要な役割をもつと考えられる。We investigated changes of trehalose level in field-isolated, natural colonies of the terrestrial cyanobacterium Nostoc commune responding to desiccation. No detectable trehalose was found in fully hydrated N. commune colonies; however, trehalose accumulation occurred in response to water loss during desiccation and high levels of trehalose were detected in the air-dried colonies. The three genes for trehalose metabolism, treZ (maltooligosyltrehalose trehalohydrolase, Mth), treY (maltooligosyltrehalose synthase, Mts), and treH (trehalase), were found as a gene cluster, and the mRNAs for these genes were detectable at similar levels during desiccation. Trehalase of N. punctiforme was heterologously expressed in E. coli cells in an active form with a molecular mass of 52kDa. Trehalase activity was strongly inhibited in the presence of 10mM NaCl while trehalose synthesis activity remained active in the presence of salt. These data suggest that the rate of trehalose production exceeds that of trehalose hydrolysis under water-stress conditions characterized by increased cellular solute concentrations. The terrestrial cyanobacterium N. commune forms a visible colony in which the cells are embedded in extracellular polysaccharides (EPSs), which play a crucial role in the extreme desiccation tolerance of this organism. The activities that hydrolyse glycoside bonds were examined using artificial nitrophenyl-linked sugars as substrates. Aβ-D-glucosidase, with a molecular mass of20kDa, was resistant to20min of boiling and was identified as a cyanobacterial fasciclin protein based on its N-terminal amino-acid sequence. The36-kDa major protein (WspA) showed heat-resistantβ-D-galactosidase activity.研究課題/領域番号:18608001, 研究期間(年度):2006–2007出典：「陸棲ラン藻における極限的な乾燥耐性の分子機構」研究成果報告書　課題番号18608001 (KAKEN：科学研究費助成事業データベース（国立情報学研究所）)　　　本文データは著者版報告書より作

Information and communication technology equipment and services for remote monitoring and health management: Survey of services and their classification for use in home care nursing

This study aims to improve the quality of home nursing care for the elderly. The report presents web-based information about devices and services for remote monitoring and health management using information and communication technology and about how they can improve home care nursing station efficiency in Japan. The search terms "elderly people," "watch over," and "service," plus "sensor" were used to narrow the search. After repeating the search using a chained search for materials and links extracted from those search results, services for home care stations particularly addressing the remote monitoring of elderly people were selected and extracted. Early detection of abnormalities for support by home health nurse responsibilities for observing the general condition of the patient was chosen as the main evaluation index of usefulness. The contractor and service cost were secondary evaluation axes. Results show 9 information communication devices and services for real-time monitoring of the elderly persons’ vital signs in real time for 24 hr, 2 of which are highly useful for early detection of abnormalities and subsequent response. Results suggest that other services might be more useful, depending on how they are used, and that general-purpose services with minimum functions and low cost of introduction and maintenance can provide more opportunities for utilization. Providing these services on a BtoBtoC model and responding to patients’ medical needs can supplement home care nursing station work, increase human resource and time efficiencies, and give patients "the feeling that a nurse is always at their bedside,” even when far away

Multiple roles of photosynthetic and sunscreen pigments in cyanobacteria focusing on the oxidative stress

Cyanobacteria have two types of sunscreen pigments, scytonemin and mycosporine-like amino acids (MAAs). These secondary metabolites are thought to play multiple roles against several environmental stresses such as UV radiation and desiccation. Not only the large molar absorption coefficients of these sunscreen pigments, but also their antioxidative properties may be necessary for the protection of biological molecules against the oxidative damages induced by UV radiation. The antioxidant activity and vitrification property of these pigments are thought to be requisite for the desiccation and rehydration processes in anhydrobiotes. In this review, the multiple roles of photosynthetic pigments and sunscreen pigments on stress resistance, especially from the viewpoint of their structures, biosynthetic pathway, and in vitro studies of their antioxidant activity, will be discussed. © 2013 by the authors; licensee MDPI, Basel, Switzerland