523 research outputs found

    Comparing Clusterings - An Overview

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    Avaliando a Justiça Ambiental em grandes projetos hidrelétricos: o caso de São Luiz do Tapajós, no Brasil

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    Electricity supply in a sustainable manner is one of the greatest challenges for human society today. Hydropower is by far the most important renewable electricity technology, but equally far from uncontroversial. Indeed, it is situated at the crossroad of socio-environmentalism trends, as strongly promoted by some as opposed by other environmentalist arguments, organisations and movements. This paper suggests Environmental Justice as an alternative approach on how to incorporate sustainability into energy planning, particularly in hydropower projects. Whereas several methods have been developed to assess Environmental Justice in an urban context, little attention has been given to electricity projects so far. A qualitative method to assess hydropower projects regarding their performance in Environmental Justice is discussed and illustrated in the case of the large hydropower project São Luiz do Tapajós in the Brazilian Amazon. As will be shown, fundamental change is necessary in Brazil if energy planning in general and hydropower projects in particular are to meet the principles of Environmental Justice.O fornecimento de energia elétrica numa maneira sustentável se encontra entre os maiores desafios para a sociedade humana hoje em dia. Energia hidrelétrica é de longe a tecnologia de eletricidade renovável mais importante, porém igualmente longe de incontroversa. De fato, se encontra na encruzilhada de correntes socioambientais, tão fortemente promovido por uns quanto rejeitado por outros argumentos, organizações e movimentos ambientalistas. Este artigo sugere a Justiça Ambiental como abordagem alternativa para incorporar a sustentabilidade no planejamento energético, particularmente em projetos hidrelétricos. Enquanto vários métodos foram desenvolvidos para avaliar Justiça Ambiental no contexto urbano, pouca atenção foi dada a projetos elétricos até agora. Um método qualitativo para avaliar projetos hidrelétricos em relação ao seu desempenho em Justiça Ambiental é discutido e ilustrado no caso do projeto hidrelétrico São Luiz do Tapajós, na Amazônia brasileira. Como vai ser mostrado, mudanças fundamentais serão necessárias no Brasil para que o planejamento energético em geral e projetos hidrelétricos em específico cumpram os princípios de Justiça Ambiental

    Modelling forest recolonization by an epiphytic lichen using a landscape genetic approach

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    The process of recolonization after disturbance is crucial for the persistence and dynamics of patch-tracking metapopulations. We developed a model to compare the spatial distribution and spatial genetic structure of the epiphytic lichen Lobaria pulmonaria within the perimeter of two reconstructed 19th century disturbances with a nearby reference area without stand-level disturbance. Population genetic data suggested that after stand-replacing disturbance, each plot was colonized by one or a few genotypes only, which subsequently spread clonally within a local neighborhood. The model (cellular automaton) aimed at testing the validity of this interpretation and at assessing the relative importance of local dispersal of clonal propagules vs. long-distance dispersal of clonal and/or sexual diaspores. A reasonable model fit was reached for the empirical data on host tree distribution, lichen distribution, and tree- and plot-level genotype diversity of the lichen in the reference area. Although model calibration suggested a predominance of local dispersal of clonal propagules, a substantial contribution of immigration of non-local genotypes by long-distance dispersal was needed to reach the observed levels of genotype diversity. The model could not fully explain the high degree of clonality after stand-replacing disturbance, suggesting that the dispersal process itself may not be stationary but depend on the ecological conditions related to disturbanc

    Bartonella taylorii; : A Model Organism for Studying; Bartonella; Infection; in vitro; and; in vivo;

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    Bartonella; spp. are Gram-negative facultative intracellular pathogens that infect diverse mammals and cause a long-lasting intra-erythrocytic bacteremia in their natural host. These bacteria translocate; Bartonella; effector proteins (Beps) into host cells; via; their VirB/VirD4 type 4 secretion system (T4SS) in order to subvert host cellular functions, thereby leading to the downregulation of innate immune responses. Most studies on the functional analysis of the VirB/VirD4 T4SS and the Beps were performed with the major zoonotic pathogen; Bartonella henselae; for which efficient; in vitro; infection protocols have been established. However, its natural host, the cat, is unsuitable as an experimental infection model.; In vivo; studies were mostly confined to rodent models using rodent-specific; Bartonella; species, while the; in vitro; infection protocols devised for; B. henselae; are not transferable for those pathogens. The disparities of; in vitro; and; in vivo; studies in different species have hampered progress in our understanding of; Bartonella; pathogenesis. Here we describe the murine-specific strain; Bartonella taylorii; IBS296 as a new model organism facilitating the study of bacterial pathogenesis both; in vitro; in cell cultures and; in vivo; in laboratory mice. We implemented the split NanoLuc luciferase-based translocation assay to study BepD translocation through the VirB/VirD4 T4SS. We found increased effector-translocation into host cells if the bacteria were grown on tryptic soy agar (TSA) plates and experienced a temperature shift immediately before infection. The improved infectivity; in vitro; was correlating to an upregulation of the VirB/VirD4 T4SS. Using our adapted infection protocols, we showed BepD-dependent immunomodulatory phenotypes; in vitro; . In mice, the implemented growth conditions enabled infection by a massively reduced inoculum without having an impact on the course of the intra-erythrocytic bacteremia. The established model opens new avenues to study the role of the VirB/VirD4 T4SS and the translocated Bep effectors; in vitro; and; in vivo;

    How public catering accelerates sustainability : a German case study

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    Public catering has become increasingly important in recent years. With increasing annual customers, the sector's impact on the environment is also growing continuously. At the same time, public catering offers a lever to promote sustainable nutrition that has rarely been used so far. Small changes in kitchen practices and food offers can thus be multiplied into a significant positive impact on environmental challenges, such as climate change or loss of biodiversity due to the large number of servings. In contrast to private households, management decisions in public catering can influence the food-related environmental impact of thousands of customers. This article deals with the nationwide level of greenhouse gas (GHG) emissions and resource use in the German public catering segment "business" and its saving potentials by different scenarios of unsupported and supported recipe revision. In this paper, we define "unsupported" as the intuitive optimization of recipes by employees of public catering businesses. In contrast, "supported" approaches had to meet specific target goals, for example of the Deutsche Gesellschaft für Ernährung; engl. German Nutrition Society or the sustainable level. Specifically, we will test how (A) an unsupported recipe revision, (B) a recipe revision based on dietary recommendations and (C) a recipe revision using scientific guidance affect the environmental impact of a dish. As a methodological framework, an online survey of public catering companies was conducted as well as a scenario analysis at menu level and at nationwide level. The results are based on empirical data on the one hand, and on extrapolations on the other. The results show that the nationwide implementation of recipe revision according to scientific guidance-such as concrete target goals for the GHG emissions per serving-can save up to 44% of resource use in the German business catering sector (which corresponds to 3.4 million tons of resources per year) and as much as 40% of GHG emissions (0.6 million tons GHG emissions per year). Even in the scenario of unsupported recipe revision, GHG and resource savings of up to 20% can be realized. The results show that public catering can reduce its material and carbon footprint by 20% overnight. Moreover, the findings show indications for the sustainable transformation of public catering. Nevertheless, it must be noted that these are some first steps of the transformation, which will require further changes with even greater impacts and political activities

    Growth dynamics after historic disturbance in a montane forest and its implications for an endangered epiphytic lichen

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    Bolli J.C., Wagner H.H., Kalwij J.M., Werth S., Cherubini P., Scheidegger C. and Rigling A. 2008. Growth dynamics after historic disturbance in a montane forest and its implications for an endangered epiphytic lichen. Bot. Helv. 118: 111 - 127. Endangered forest species are often negatively affected by disturbances, which may have long-lasting effects on the distribution, abundance and genetic diversity of such species. To understand the effects of historic disturbances, detailed knowledge of the conditions for survival and recolonisation is needed, and this requires precise information on the perimeter and severity of historic disturbance events. We reconstructed a major historic disturbance (intensive logging followed by windthrow and fire in 1871) in the Swiss Jura mountains to analyse its effect on the disturbance-sensitive epiphytic lichen Lobaria pulmonaria. Tree-ring analysis of old and young Norway spruce trees (Picea abies L.), sampled systematically on a 100 m grid, revealed that (1) the disturbance was of intermediate severity, (2) a large, well-defined area of disturbance was created, and (3) an undisturbed zone remained in the centre of the disturbed area. Acomparison with lichen genetic data from a previous survey revealed that genetic diversity was particularly high in the remnant zone. These results suggest that the lichen survived there, and that it re-colonised the disturbed area both from the edge and from the remnant undisturbed zone. This illustrates that a detailed reconstruction of historic disturbances, as achieved with dendroecology, is very important for understanding the recolonisation process and thus, the conditions for the long-term persistence of disturbance-sensitive species in a dynamic landscap

    QUANTIFYING DISPERSAL AND ESTABLISHMENT LIMITATION IN A POPULATION OF AN EPIPHYTIC LICHEN

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    Dispersal is a process critical for the dynamics and persistence of metapopulations, but it is difficult to quantify. It has been suggested that the old-forest lichen Lobaria pulmonaria is limited by insufficient dispersal ability. We analyzed 240 DNA extracts derived from snow samples by a L. pulmonaria-specific real-time PCR (polymerase chain reaction) assay of the ITS (internal transcribed spacer) region allowing for the discrimination among propagules originating from a single, isolated source tree or propagules originating from other locations. Samples that were detected as positives by real-time PCR were additionally genotyped for five L. pulmonaria microsatellite loci. Both molecular approaches demonstrated substantial dispersal from other than local sources. In a landscape approach, we additionally analyzed 240 snow samples with real-time PCR of ITS and detected propagules not only in forests where L. pulmonaria was present, but also in large unforested pasture areas and in forest patches where L. pulmonaria was not found. Monitoring of soredia of L. pulmonaria transplanted to maple bark after two vegetation periods showed high variance in growth among forest stands, but no significant differences among different transplantation treatments. Hence, it is probably not dispersal limitation that hinders colonization in the old-forest lichen L. pulmonaria, but ecological constraints at the stand level that can result in establishment limitation. Our study exemplifies that care has to be taken to adequately separate the effects of dispersal limitation from a limitation of establishment

    Human hair follicle eqivalents in vitro for transplantation and chip-based substance testing : From 22nd European Society for Animal Cell Technology (ESACT) Meeting on Cell Based Technologies Vienna, Austria. 15-18 May 2011

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    First published by BioMed Central: Marx, Uwe ; Lindner, Gerd ; Wagner, Ilka ; Horland, Reyk ; Atac, Beren ; Hoffmann, Silke ; Gruchow, Mathias ; Sonntag, Frank ; Klotzbach, Udo ; Lauster, Roland: Human hair follicle equivalents in vitro for transplantation and chip-based substance testing : From 22nd European Society for Animal Cell Technology (ESACT) Meeting on Cell Based Technologies Vienna, Austria. 15-18 May 2011. - In: BMC Proceedings. - ISSN 1753-6561 (online). - 5 (2011), suppl. 8, O7. - doi:10.1186/1753-6561-5-S8-O7

    Control software model checking using bisimulation functions for nonlinear systems

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    Abstract — This paper extends a method for integrating source-code model checking with dynamic system analysis to verify properties of controllers for nonlinear dynamic systems. Source-code model checking verifies the correctness of control systems including features that are introduced by the software implementation, such as concurrency and task interleaving. Sets of reachable continuous states are computed using numerical simulation and bisimulation functions. The technique as origi-nally proposed handles stable dynamic systems with affine state equations for which quadratic bisimulation functions can be computed easily. The extension in this paper handles nonlinear systems with polynomial state equations for which bisimulation functions can be computed in some cases using sum-of-squares (SoS) techniques. The paper presents the convex optimizations required to perform control system verification using a source-code model checker, and the method is illustrated for an example of a supervisory control system. I

    Calibration by differentiation – Self‐supervised calibration for X‐ray microscopy using a differentiable cone‐beam reconstruction operator

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    High‐resolution X‐ray microscopy (XRM) is gaining interest for biological investigations of extremely small‐scale structures. XRM imaging of bones in living mice could provide new insights into the emergence and treatment of osteoporosis by observing osteocyte lacunae, which are holes in the bone of few micrometres in size. Imaging living animals at that resolution, however, is extremely challenging and requires very sophisticated data processing converting the raw XRM detector output into reconstructed images. This paper presents an open‐source, differentiable reconstruction pipeline for XRM data which analytically computes the final image from the raw measurements. In contrast to most proprietary reconstruction software, it offers the user full control over each processing step and, additionally, makes the entire pipeline deep learning compatible by ensuring differentiability. This allows fitting trainable modules both before and after the actual reconstruction step in a purely data‐driven way using the gradient‐based optimizers of common deep learning frameworks. The value of such differentiability is demonstrated by calibrating the parameters of a simple cupping correction module operating on the raw projection images using only a self‐supervisory quality metric based on the reconstructed volume and no further calibration measurements. The retrospective calibration directly improves image quality as it avoids cupping artefacts and decreases the difference in grey values between outer and inner bone by 68–94%. Furthermore, it makes the reconstruction process entirely independent of the XRM manufacturer and paves the way to explore modern deep learning reconstruction methods for arbitrary XRM and, potentially, other flat‐panel computed tomography systems. This exemplifies how differentiable reconstruction can be leveraged in the context of XRM and, hence, is an important step towards the goal of reducing the resolution limit of in vivo bone imaging to the single micrometre domain
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