Finite record sets of chip-firing games

A finite graph with an assignment of non-negative integers to vertices gives chip-firing games. Chip-firing games determine languages (sets of words) called the record sets of legal games. Bj\"orner, Lov\'asz and Shor found several properties that are satisfied by record sets. In this paper, we will find two more properties of record sets. Under the assumption that the record set is finite and the game fires only two vertices, these properties characterize the record sets of graphs.Comment: 7 page

Sensitivity mapping for seabirds and offshore wind power farms : A case study of Slaty-backed gulls in Hokkaido

洋上風力発電は陸上風力発電よりも極めて大きな発電量を持つことから、近年気候変動問題の緩和策として最も有力視されている再生可能エネルギーのひとつである。その一方で、風車への海鳥の衝突等、野生動物への影響も懸念されている。このため、海鳥の生息に配慮した風力発電事業計画のための実用的なセンシティビティマップが求められるが、多くの国で作成されていない。本研究は、海鳥類への影響を最小限にとどめることを目的に、オオセグロカモメ Larus schistisagusをケーススタディとし、本種の生息場選択に関わる要因を明らかにし、センシティビティマップを作成した。 2018年 6－8月に、北海道道東地方に生息するオオセグロカモメ 6個体に GPSロガーを装着し 5分間隔で利用場所を特定した。オオセグロカモメの利用頻度は海水面温度、クロロフィル a、および営巣地からの距離が関係しており、海水面温度やクロロフィル aの上昇に伴い増加し、営巣地からの距離に応じて減少した。しかし、営巣地からの距離が 25 kmを越えた辺りからは横ばいとなった。これらの結果を用いてセンシティビティマップを作成したところ、営巣地に近接した海域だけでなく、遠方であっても潜在的に餌資源量が多い海域であれば、本種が風車に衝突する可能性が高くなることが示唆された。国内での洋上風力発電事業が計画されつつある今日では、本研究で示された手順で緊急にセンシティビティマップを作成し、事前の開発地選択に活用する必要がある。Offshore wind energy is a renewable energy source that offers an opportunity to reduce greenhouse gas emissions while increasing energy security. However, many ecologists have suggested that offshore wind farms may have severe negative impacts on wildlife, especially seabirds. Thus, balancing seabird conservation with human energy demands is necessary when developing wind farms. Bird sensitivity mapping is a powerful and practical tool that can determine turbine collision risk within specific areas; however, sensitivity maps have seldom been generated for seabirds. Focusing on the Slaty-backed gull (Larus schistisagus), a red-listed species that often collides with wind turbines, we determined factors affecting habitat selection with the goal of reducing negative impacts of offshore wind farms. We then generated a sensitivity map using habitat modeling. GPS loggers set to record at 5-minute intervals between June and August 2018 were attached to six Slaty-backed gulls residing in Ochiishi Bay, Nemuro Prefecture, Japan. A Gaussian mixed model indicated that habitat selection was related to food availability (as determined by sea surface temperature and chlorophyll a content) and distance to the nest site. Sea surface temperature and chlorophyll a content were positively related area visitation frequency of Slaty-backed gulls, whereas distance to nest site was negatively correlated. Moreover, area visitation frequency was unchanged when the distance from the nest site was > 25 km. The sensitivity map indicated that areas both near and far from nest sites with potentially abundant food resources were high-risk areas with respect to turbine collisions for Slaty-backed gulls. Based on these results, we advocate the use of sensitivity mapping to reduce interactions between offshore wind farms and seabirds, especially for species that often forage far from their nest sites

Spin susceptibility and effective mass of two-dimensional electrons in MgxZn1-xO/ZnO heterostructures

We report measurements of the spin susceptibility and the electron effective mass for two-dimensional electrons confined at the interfaces of MgxZn1-xO/ZnO single heterostructures (x = 0.05, 0.08, and 0.11), grown by molecular-beam epitaxy on (0001) ZnO substrates. By tuning the built-in polarization through control of the barrier composition, the electron density was systematically varied in the range of 5.6 x 10^11 to 1.6 x 10^12 cm^-2, corresponding to a range of 3.1 < rs < 5.2, where rs is the average electron spacing measured in units of the effective Bohr radius. We used the coincidence technique, where crossings of the spin-split Landau levels occur at critical tilt angles of magnetic field, to evaluate the spin susceptibility. In addition, we determined the effective mass from the temperature dependence of the Shubnikov-de Haas oscillations measured at the coincidence conditions. The susceptibility and the effective mass both gradually increase with decreasing electron density, reflecting the role of electron-electron interaction.Comment: 4 pages, 4figures, accepted for publication in Phys. Rev.

Molecular and histopathological characterization of cryptosporidium and eimeria species in bats in Japan

application/pdfBats are potential reservoirs of Cryptosporidium and Eimeria. The genus Cryptosporidium infects various vertebrates and causes a diarrheal disease known as cryptosporidiosis. Many epidemiological studies in wild animals have been performed; however, most of them relied on only PCR-based detection because of the difficulty of performing pathological analyses. Accordingly, the natural host and pathogenicity of Cryptosporidium bat genotypes remain unclear. In this study, we captured Eptesicus nilssonii (Northern bats) in Hokkaido, Japan. Of the three intestinal samples obtained, two were positive for Cryptosporidium spp. and one was positive for Eimeria spp. The corresponding microorganisms were also confirmed histopathologically. We detected the novel Cryptosporidium bat genotype and Eimeria rioarribaensis in bat intestine. © 2018 The Japanese Society of Veterinary Science

Synthesis and Functionalization of a 1,4-Bis(trimethylsilyl)tetrasila-1,3-diene through the Selective Cleavage of Si(sp²)–Si(sp³) Bonds under Mild Reaction Conditions

Although the oxidative coupling of disilenides, i.e., the disilicon analogues of vinyl anions, represents a promising route to extend the conjugation between SiSi double bonds, previously reported synthetic routes to disilenides involve strongly reducing conditions. Herein, we report a novel synthetic route to disilenides from stable disilenes via the selective cleavage of Si­(sp²)–Si­(sp³) bonds under milder reaction conditions. Using this method, a 1,4-bis­(trimethylsilyl)­tetrasila-1,3-diene (<b>5</b>) was synthesized from the corresponding silyl-substituted disilene. Moreover, Et₃Si-substituted tetrasila-1,3-diene <b>7</b> was synthesized via tetrasila-1,3-dien-1-ide <b>6</b>, which is the first example of a functionalized tetrasila-1,3-diene

CYP2C19 variants and epoxyeicosatrienoic acids in patients with microvascular angina

Categorization as a cytochrome P450 (CYP) 2C19 poor metabolizer (PM) is reported to be an independent risk factor for cardiovascular disease. Epoxyeicosatrienoic acids (EETs) are metabolites of arachidonic acid by CYP2C19 epoxygenases and anti-inflammatory properties, especially in microvascular tissues. We examined the impact of CYP2C19 polymorphisms and EETs on the patients with microvascular angina (MVA) caused by coronary microvascular dysfunction. We examined CYP2C19 genotypes in patients with MVA (n = 81). MVA was defined as absence of coronary artery stenosis and epicardial spasms, and the presence of inversion of lactic acid levels between intracoronary and coronary sinuses in acetylcholine-provocation test or the adenosine-triphosphate-induced coronary flow reserve ratio was below 2.5. CYP2C19 PM have two loss-of-functon alleles (*2, *3). We measured serum dihydroxyeicosatrienoic acid (DHET) as representative EET metabolite. In MVA, the patients with CYP2C19 PM were 34.6% and high sense C-reactive protein (hs-CRP) levels in CYP2C19 PM were significantly higher than that of non-PM group (0.165 ± 0.116 vs. 0.097 ± 0.113 mg/dL, P = 0.026). Moreover, DHET levels in CYP2C19 PM were significantly lower than that of non-PM (10.4 ± 4.58 vs. 15.6 ± 11.1 ng/mL, P = 0.003 (11, 12-DHET), 12.1 ± 3.79 vs. 17.3 ± 6.49 ng/mL, P = 0.019 (14, 15-DHET)). The decline of EET owing to CYP2C19 variants may affects coronary microvascular dysfunction via chronic inflammation