233 research outputs found

    Mountains as Evolutionary Arenas: Patterns, Emerging Approaches, Paradigm Shifts, and Their Implications for Plant Phylogeographic Research in the Tibeto-Himalayan Region

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    Recently, the “mountain-geobiodiversity hypothesis” (MGH) was proposed as a key concept for explaining the high levels of biodiversity found in mountain systems of the Tibeto-Himalayan region (THR), which comprises the Qinghai–Tibetan Plateau, the Himalayas, and the biodiversity hotspot known as the “Mountains of Southwest China” (Hengduan Mountains region). In addition to the MGH, which covers the entire life span of a mountain system, a complementary concept, the so-called “flickering connectivity system” (FCS), was recently proposed for the period of the Quaternary. The FCS focuses on connectivity dynamics in alpine ecosystems caused by the drastic climatic changes during the past ca. 2.6 million years, emphasizing that range fragmentation and allopatric speciation are not the sole factors for accelerated evolution of species richness and endemism in mountains. I here provide a review of the current state of knowledge concerning geological uplift, Quaternary glaciation, and the main phylogeographic patterns (“contraction/recolonization,” “platform refugia/local expansion,” and “microrefugia”) of seed plant species in the THR. In addition, I make specific suggestions as to which factors future avenues of phylogeographic research should take into account based on the fundamentals presented by the MGH and FCS, and associated complementary paradigm shifts

    An Integrated Software Platform for Best Estimate Safety Analyses of Nuclear Power Plants

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    Nuclear power plant safety is granted through the demonstration that regulatory acceptance criteria are fulfilled by the provided (calculated) analyses of the NPP performances and sufficient safety margins are respected during normal operation, anticipated transients and postulated accident conditions. Safety margins are very hard to determine in absolute terms, numerical calculations are used to assess their values. Over the last 30 years an extensive effort has been carried out aiming to improve the knowledge of the nuclear power plant behaviour under transient scenarios. The development of Best Estimate (BE) computer codes are the direct consequence of these noteworthy efforts. The availability of more sophisticated and specialized computer codes gives the analyst the possibility to perform very detailed analysis in all the fields involved in the safety of a NPP: thermal-hydraulics, CFD, 3D neutron kinetics etc. The possibility to create a software environment where a multidisciplinary problem can be solved adopting different specialized codes able to exchange data among them is a fruitful approach to the problem aiming to improve the results. The computational tools, adopted in best-estimate approach in licensing, include a) the best estimate computer codes; b) the nodalizations together with the procedures for the development and the qualification; c) the uncertainty methodology. The Nuclear Research Group of San Piero a Grado of the University of Pisa has developed a software platform with 15 interacting computer codes. Such platform covers the reactor simulation multidisciplinary problem from generation of neutron cross-sections, through system thermal-hydraulic analyses, up to detailed structural and fuel mechanics studies and it embeds software procedures for automatized data transfer between codes. Together with methodological procedures for nodalizations development and qualification the platform leads to a great decrease of the human induced error in the results. The developed platform has been tested and successfully applied to perform the safety analyses required by the Chapter 15 of the Final Safety Analysis Report of the CNA-2 nuclear power plant in Argentina

    Coupling of Thermal-Hydraulics and I&C for Licensing Analyses

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    The BEPU (Best Estimate Plus Uncertainty) approach constitutes a valuable and, under some circumstances, an unavoidable tool to demonstrate the safety of NPP (Nuclear Power Plants). Within the licensing process of the Atucha II PHWR (Pressurized Heavy Water Reactor) the BEPU approach has been followed for issuing the Chapter 15 of the FSAR (Final Safety Analysis Report). Namely, the BEPU approach replaced the classical conservative approach. The selection of PIE (Postulated Initiating Events) and, the analysis of each PIE by best estimate models supported by uncertainty evaluation constitute key elements for BEPU. An outline of the BEPU approach is included in the paper, which, otherwise focuses on the simulation needs for Instrumentation and Control (I & C). Sample results from the analysis of PIE are included in the paper. It is demonstrated that the simulation of I&C is necessary to evaluate the safety of the concerned NPP; furthermore, the simulation shall be part of the accident analysis in Chapter 15 of FSA

    Integrated Nuclear Knowledge Management System – NUTEMA

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    Knowledge Management has become one of the most important issues for the nuclear industry. On the one hand, the amount of codifiable knowledge in the nuclear technology area saw a steep increase in the last years; on the other hand, due to the “generation gap” in the nuclear industry it became very challenging to organize the seamless transfer of the noncodifiable knowledge from one generation of engineers to the other. Computer aided systems so far where aiming at to preserve the codifiable knowledge. The present paper introduces a system that should support knowledge management not only dealing with the codifiable part of it, but also address broader aspects (which includes the management of non-codifiable knowledge).- NUTEMA. The integrated nuclear knowledge management system NUTEMA should provide interactive combination of information and methods, but also identifying competences which more adequately fit to a given task, keeping track of keeping skills of the experts within an organization. Application is foreseen in nuclear engineering fields as system design, operation and maintenance plant and process modifications, standardization, certification and even for licensing-related tasks. The system combines an extensively diverse and modular database with computer based simulations including a scientific software platform. NUTEMA is conceived to operate in different modes, for example collecting and retrieving database knowledge, training applications, NPP operations support, computer code applications, and as plant analyzer. This paper will present two examples; one acting as at a supporting tool for typical NPP plant modification: In a second case, application on review and optimization of operational process is described. Despite the provided examples deal with different objectives and methods associated with different stages of an NPP lifetime, (design and operation) both are supported by the integrated nuclear knowledge management system

    Accident Management in VVER-1000

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    The present paper deals with the investigation study on accident management in VVER-1000 reactor type conducted in the framework of a European Commission funded project. The mentioned study involved both experimental and computational fields. The purpose of this paper is to summarize the main findings from the execution of a wide-range analysis focused on AM in VVER-1000 with main regard to the qualification of computational tools and the proposal for an optimal AM strategy for this kind of NPP

    Analysis of Unusual Sulfated Constituents and Anti-infective Properties of Two Indonesian Mangroves, Lumnitzera littorea and Lumnitzera racemosa (Combretaceae)

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    Lumnitzera littorea and Lumnitzera racemosa are mangrove species distributed widely along the Indonesian coasts. Besides their ecological importance, both are of interest owing to their wealth of natural products, some of which constitute potential sources for medicinal applications. We aimed to discover and characterize new anti-infective compounds, based on population-level sampling of both species from across the Indonesian Archipelago. Root metabolites were investigated by TLC, hyphenated LC-MS/MS and isolation, the internal transcribed spacer (ITS) region of rDNA was used for genetic characterization. Phytochemical characterization of both species revealed an unusual diversity in sulfated constituents with 3,3’,4’-tri-O-methyl-ellagic acid 4-sulfate representing the major compound in most samples. None of these compounds was previously reported for mangroves. Chemophenetic comparison of L. racemosa populations from different localities provided evolutionary information, as supported by molecular phylogenetic evidence. Samples of both species from particular locations exhibited anti-bacterial potential (Southern Nias Island and East Java against Gram-negative bacteria, Halmahera and Ternate Island against Gram-positive bacteria). In conclusion, Lumnitzera roots from natural mangrove stands represent a promising source for sulfated ellagic acid derivatives and further sulfur containing plant metabolites with potential human health benefits

    Recent Applications of RELAP5-3D at GRNSPG

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    CNA2 : FSAR activities Standard Consolidated Reference Experimental Database MASLWR benchmark OECD benchmarks CHF calculation in low mass flux condition Turbulence effects in Relap5-3

    Comparison of two arthroscopic pump systems based on image quality

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    The effectiveness of arthroscopic pump systems has been investigated with either subjective measures or measures that were unrelated to the image quality. The goal of this study is to determine the performance of an automated pump in comparison to a gravity pump based on objective assessment of the quality of the arthroscopic view. Ten arthroscopic operations performed with a gravity pump and ten performed with an automated pump (FMS Duo system) were matched on duration of the surgery and shaver usage, type of operation, and surgical experience. Quality of the view was defined by means of the presence or absence of previously described definitions of disturbances (bleeding, turbidity, air bubbles, and loose fibrous tissue). The percentage of disturbances for all operations was assessed with a time-disturbance analysis of the recorded operations. The Mann–Whitney U test shows a significant difference in favor of the automated pump for the presence of turbidity only (Exact Sig. [2*(1-tailed Sig.)] = 0.015). Otherwise, no differences were determined (Exact Sig. [2*(1-tailed Sig.)] > 0.436). A new objective method is successfully applied to assess efficiency of pump systems based on the quality of the arthroscopic view. Important disturbances (bleeding, air bubbles, and loose fibrous tissue) are not reduced by an automated pump used in combination with a tourniquet. The most frequent disturbance turbidity is reduced by around 50%. It is questionable if this result justifies the use of an automated pump for straightforward arthroscopic knee surgeries using a tourniquet

    Final report on rod cladding failure during SGTR

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    Achievements on modelling fission product release from defective rods during a steam generator tube rupture transient and iodine spiking have been obtained and presented in this deliverable

    Kinome rewiring reveals AURKA limits PI3K-pathway inhibitor efficacy in breast cancer.

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    Dysregulation of the PI3K-AKT-mTOR signaling network is a prominent feature of breast cancers. However, clinical responses to drugs targeting this pathway have been modest, possibly because of dynamic changes in cellular signaling that drive resistance and limit drug efficacy. Using a quantitative chemoproteomics approach, we mapped kinome dynamics in response to inhibitors of this pathway and identified signaling changes that correlate with drug sensitivity. Maintenance of AURKA after drug treatment was associated with resistance in breast cancer models. Incomplete inhibition of AURKA was a common source of therapy failure, and combinations of PI3K, AKT or mTOR inhibitors with the AURKA inhibitor MLN8237 were highly synergistic and durably suppressed mTOR signaling, resulting in apoptosis and tumor regression in vivo. This signaling map identifies survival factors whose presence limits the efficacy of targeted therapies and reveals new drug combinations that may unlock the full potential of PI3K-AKT-mTOR pathway inhibitors in breast cancer
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