555 research outputs found

    A large-scale perspective on ecosystems

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    Interactions between ecological elements must be better understood in order to construct an ecological life support system in space. An index was devised to describe the complexity of material cyclings within a given ecosystem. It was then applied to the cyclings of bioelements in various systems of material cyclings including the whole Earth and national economies. The results show interesting characteristics of natural and man-made systems

    Minimum 0-Extension Problems on Directed Metrics

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    For a metric μ\mu on a finite set TT, the minimum 0-extension problem 0-Ext[μ][\mu] is defined as follows: Given VTV\supseteq T and  c:(V2)Q+\ c:{V \choose 2}\rightarrow \mathbf{Q_+}, minimize c(xy)μ(γ(x),γ(y))\sum c(xy)\mu(\gamma(x),\gamma(y)) subject to γ:VT, γ(t)=t (tT)\gamma:V\rightarrow T,\ \gamma(t)=t\ (\forall t\in T), where the sum is taken over all unordered pairs in VV. This problem generalizes several classical combinatorial optimization problems such as the minimum cut problem or the multiterminal cut problem. The complexity dichotomy of 0-Ext[μ][\mu] was established by Karzanov and Hirai, which is viewed as a manifestation of the dichotomy theorem for finite-valued CSPs due to Thapper and \v{Z}ivn\'{y}. In this paper, we consider a directed version 0\overrightarrow{0}-Ext[μ][\mu] of the minimum 0-extension problem, where μ\mu and cc are not assumed to be symmetric. We extend the NP-hardness condition of 0-Ext[μ][\mu] to 0\overrightarrow{0}-Ext[μ][\mu]: If μ\mu cannot be represented as the shortest path metric of an orientable modular graph with an orbit-invariant ``directed'' edge-length, then 0\overrightarrow{0}-Ext[μ][\mu] is NP-hard. We also show a partial converse: If μ\mu is a directed metric of a modular lattice with an orbit-invariant directed edge-length, then 0\overrightarrow{0}-Ext[μ][\mu] is tractable. We further provide a new NP-hardness condition characteristic of 0\overrightarrow{0}-Ext[μ][\mu], and establish a dichotomy for the case where μ\mu is a directed metric of a star

    Carbon and Nitrogen Isotopic Signatures of Bat Guanos as a Record of Past Environments

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    Carbon and nitrogen isotope ratios were measured for various ecogeochemical samples relevant to bat guano ecosystems. In particular, ca. 800-year-old subfossil guano from Jackson\u27s Bay Cave Compex, Jamaica, yielded ratios similar to the modern guano from other Jamaican bat caves but quite different from modern guano of the same area. Diagenetic change and differences in bat food habits were unlikely explanations for the observation. Instead, insects that feed on C4 and CAM plants were the main prey for the bats in present Jackson\u27s Bay area, while the ultimate source of organic matter for bats in other Jamaican caves and for the bats that deposited guano in Jackson\u27s Bay Great Cave ca. 800 years ago were C3 photosynthesis. We suggest that the isotopic data indicate that the surrounding environment experienced a significant mesic episode in the recent past. This mesic climate would have supported a large population of bats, which in turn would have accumulated significant quantities of guano. The subsequent return to the more xeric conditions prevailing today would have caused a drastic reduction in bat population size and effectively ended significant guano accumulation. Fossil guano from Carlsbad Caverns, New Mexico, U.S.A., suggested that native C3 plants might have been more abundant in Wisconsinan than today. Isotope analyses of old guanos from Bat Cave in Grand Canyon National Park, Arizona, U. S. A., found a possible implication that C4 photosynthesis might have had contributed a little more to the bats\u27 diet in the cave before the construction of Glen Canyon Dam

    Nitrogen and Carbon Isotope Studies of a Bat Guano Core From Eagle Creek Cave, Arizona, USA

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    Nitrogen and carbon isotope ratios were studied in a stratified deposit of guano of Mexican Free-tailed bats in Eagle Creek Cave, Arizona, U.S.A. Little diagenetic change was observed over the 25-year time span of the guano deposit. High aridity and reduced circulation of air in the cave are hypothesized to have slowed the normally rapid decomposition of the excreta and the subsequent escape of resultant ammonia. The results suggest the high dependency of the speed of diagenetic change on specific physical and other conditions of the caves and indicate that great care need be exercised in the interpretation of the isotopic ecogeochemistry of old guano. Relative contribution of C3 photosynthesis to the food chain leading to the bats was estimated to be more than C4 photosynthesis

    Electronic Properties of BaPtP with a Noncentrosymmetric Cubic Crystal Structure

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    We report the synthesis, electronic properties, and electronic structure of LaIrSi-type BaPtP with a noncentrosymmetric cubic crystal structure. Electrical resistivity and heat capacity data taken by using polycrystalline samples indicated that BaPtP is a metal, which was further supported by first principles calculations. A polycrystalline sample of BaPtP showed a zero resistivity below 0.2 K due to the superconducting transition. The first principles calculation results indicated that the spin splitting at around the Fermi energy is large in BaPtP. These results suggest that BaPtP is likely to exhibit interesting physical properties caused by a strong spin-orbit coupling of 5d electrons in the Pt atoms.Comment: 4 pages, 4 figures, JPS Conf. Proc., accepte

    HNF-1β過剰発現を呈する卵巣明細胞癌においてGSK-3βは新たなシグナル伝達経路を介在する

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    Deubiquitinase USP28 is a target gene of the transcription factor HNF1 homeobox β (HNF-1β), which promotes the survival of ovarian clear cell carcinoma (OCCC) cell lines. However, the pharmacological inhibition of HNF-1β can cause several adverse effects as it is abundantly expressed in numerous organ systems, including the kidney, liver, pancreas and digestive tract. Therefore, small interfering RNA (siRNA) screening was performed in the current study to identify other potential downstream targets of the HNF-1β-mediated pathway. The results revealed that glycogen synthase kinase-3β (GSK-3β) may be a potential downstream target affecting cell viability. To further clarify the effects of GSK-3β, two human OCCC cell lines, TOV-21G (HNF-1β overexpressing line) and ES2 (HNF-1β negative) were transfected with siRNA targeting GSK-3β or control vectors. Loss-of-function studies using RNAi-mediated gene silencing indicated that HNF-1β facilitated GSK-3β expression, resulting in the loss of phosphorylated nuclear factor-κB (p-NFκB) and the reduction of TOV-21G cell proliferation. The cell proliferation assay also revealed that GSK-3β inhibitors rescued the effects of HNF-1β silencing on cell viability in a dose-dependent manner. Furthermore, the GSK-3β inhibitor, AR-A014418, effectively inhibited tumor cell proliferation in a xenograft mouse model. In conclusion and to the best of our knowledge, the current study was the first to determine that GSK-3β is a target gene of HNF-1β. In addition, the results of the present study revealed the novel HNF-1β-GSK-3β-p-NFκB pathway, occurring in response to DNA damage. Targeting this pathway may therefore represent a putative, novel, anticancer strategy in patients with OCCC.博士(医学)・甲第785号・令和3年3月15日Copyright: © Kawaharaet al. This is an open access article distributed under theterms of CreativeCommons Attribution License(https://creativecommons.org/licenses/by-nc-nd/4.0/)

    Feature Article A Novel Instrument for Simultaneous In Situ NOx and O 2 Measurement Applied to Coal-fired Power Plant Applications

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    HORIBA has developed the INM-700, a low cost, low-maintenance, in situ instrument for simultaneously monitoring NOx and O 2 concentrations aimed at industrial applications. The INM-700 is based on a novel use of a solid-state zirconium oxide sensor strategy. Using this new configuration, the instrument eliminates the drawbacks such as sample handling and conditioning and time lags associated with more conventional extractive sampling methods. In this paper, we review the development and testing of the HORIBA INM-700 in preparation for deployment on selective catalytic reduction (SCR) units on coal-fired power plants. We describe the sensor technology developments and modifications implemented to integrate the instrument to the SCR application. We show data to track NOx and O 2 concentrations at a typical power plant and compare that data to conventional extractive methods. The HORIBA INM-700 data tracks plant history data sets and demonstrates this innovative and affordable approach to industrial process monitoring

    Optimization of treatment strategy

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    The purpose of this study was to predict the survival time of patients with malignant glioma after radiotherapy with high accuracy by considering additional clinical factors and optimize the prescription dose and treatment duration for individual patient by using a machine learning model. A total of 35 patients with malignant glioma were included in this study. The candidate features included 12 clinical features and 192 dose–volume histogram (DVH) features. The appropriate input features and parameters of the support vector machine (SVM) were selected using the genetic algorithm based on Akaike’s information criterion, i.e. clinical, DVH, and both clinical and DVH features. The prediction accuracy of the SVM models was evaluated through a leave-one-out cross-validation test with residual error, which was defined as the absolute difference between the actual and predicted survival times after radiotherapy. Moreover, the influences of various values of prescription dose and treatment duration on the predicted survival time were evaluated. The prediction accuracy was significantly improved with the combined use of clinical and DVH features compared with the separate use of both features (P < 0.01, Wilcoxon signed rank test). Mean ± standard deviation of the leave-one-out cross-validation using the combined clinical and DVH features, only clinical features and only DVH features were 104.7 ± 96.5, 144.2 ± 126.1 and 204.5 ± 186.0 days, respectively. The prediction accuracy could be improved with the combination of clinical and DVH features, and our results show the potential to optimize the treatment strategy for individual patients based on a machine learning model
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