177 resultados para global cooling


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The competitiveness of businesses is increasingly dependent on their electronic networks with customers, suppliers, and partners. While the strategic and operational impact of external integration and IOS adoption has been extensively studied, much less attention has been paid to the organizational and technical design of electronic relationships. The objective of our longitudinal research project is the development of a framework for understanding and explaining B2B integration. Drawing on existing literature and empirical cases we present a reference model (a classification scheme for B2B Integration). The reference model comprises technical, organizational, and institutional levels to reflect the multiple facets of B2B integration. In this paper we onvestigate the current state of electronic collaboration in global supply chains focussing on the technical view. Using an indepth case analysis we identify five integration scenarios. In the subsequent confirmatory phase of the research we analyse 112 real-world company cases to validate these five integration scenarios. Our research advances and deepens existing studies by developing a B2B reference model, which reflects the current state of practice and is independent of specific implementation technologies. In the next stage of the research the emerging reference model will be extended to create an assessment model for analysing the maturity level of a given company in a specific supply chain.

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Functionally relevant large scale brain dynamics operates within the framework imposed by anatomical connectivity and time delays due to finite transmission speeds. To gain insight on the reliability and comparability of large scale brain network simulations, we investigate the effects of variations in the anatomical connectivity. Two different sets of detailed global connectivity structures are explored, the first extracted from the CoCoMac database and rescaled to the spatial extent of the human brain, the second derived from white-matter tractography applied to diffusion spectrum imaging (DSI) for a human subject. We use the combination of graph theoretical measures of the connection matrices and numerical simulations to explicate the importance of both connectivity strength and delays in shaping dynamic behaviour. Our results demonstrate that the brain dynamics derived from the CoCoMac database are more complex and biologically more realistic than the one based on the DSI database. We propose that the reason for this difference is the absence of directed weights in the DSI connectivity matrix.

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Pseudomonas aeruginosa undergoes spontaneous mutation that impairs secretion of several extracellular enzymes during extended cultivation in vitro in rich media, as well as during long-term colonization of the cystic fibrosis lung. A frequent type of strong secretion deficiency is caused by inactivation of the quorum-sensing regulatory gene lasR. Here we analyzed a spontaneously emerging subline of strain PAO1 that exhibited moderate secretion deficiency and partial loss of quorum-sensing control. Using generalized transduction, we mapped the secretion defect to the vfr gene, which is known to control positively the expression of the lasR gene and type II secretion of several proteases. We confirmed this secretion defect by sequencing and complementation of the vfr mutation. In a reconstruction experiment conducted with a 1:1 mixture of wild-type strain PAO1 and a vfr mutant of PAO1, we observed that the vfr mutant had a selective advantage over the wild type after growth in static culture for 4 days. Under these conditions, spontaneous vfr emerged in a strain PAO1 population after four growth cycles, and these mutants accounted for more than 40% of the population after seven cycles. These results suggest that partial or complete loss of quorum sensing and secretion can be beneficial to P. aeruginosa under certain environmental conditions.

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Pseudomonas fluorescens strain CHA0 suppresses various plant diseases caused by soil-borne fungi. The pseudomonad produces the antimicrobial metabolites 2,4-diacetylphloroglucinol (Phl), pyoluteorin (Plt) and hydrogen cyanide, which are important for disease suppression, as well as the siderophores pyoverdine (Pvd), salicylic acid (Sal) and pyochelin (Pch). In the current work, a derivative of CHA0 with a mutation in the global regulator gene gacA (GacA−), which is unable to produce Phl, Plt and HCN, failed to protect the dicotyledonous plants cress and cucumber against damping-off caused by Pythium ultimum. In contrast, the GacA− mutant could still protect the Gramineae wheat and maize against damping-off mediated by the same strain of P. ultimum, and wheat against take-all caused by Gaeumannomyces graminis. However, the GacA− mutant overproduced Pch and Pvd. To gain more insight into disease protection afforded by the GacA− mutant, a GacA− Pvd− double mutant (strain CHA496) was constructed by gene replacement. Strain CHA496 overproduced Pch and Sal compared with CHA0 and protected wheat against P. ultimum and G. graminis, whereas cress and cucumber were not protected. Addition of FeCl3 repressed Pch and Sal production by strain CHA496 in vitro and impaired the protection of wheat in soil microcosms. In conclusion, a functional gacA gene was necessary for the protection of dicotyledons against root diseases, but not for that of Gramineae. Results indicated also that Pch and/or Sal were involved in the ability of the GacA− Pvd− mutant of CHA0 to suppress root diseases in Gramineae.

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Fertility and flower development are both controlled in part by jasmonates, fatty acid-derived mediators produced via the activity of 13-lipoxygenases (13-LOXs). The Arabidopsis thaliana Columbia-0 reference genome is predicted to encode four of these enzymes and it is already known that one of these, LOX2, is dispensable for fertility. In this study, the roles of the other three 13-LOXs (LOX3, LOX4 and LOX6) were investigated in single and double mutants. Four independent lox3 lox4 double mutants assembled with different mutated lox3 and lox4 alleles had fully penetrant floral phenotypes, displaying abnormal anther maturation and defective dehiscence. The plants were no longer self-fertile and pollen was not viable. Fertility in the double mutant was restored genetically by complementation with either the LOX3 or the LOX4 cDNAs and biochemically with exogenous jasmonic acid. Furthermore, deficiency in LOX3 and LOX4 causes developmental dysfunctions, compared to wild type; lox3 lox4 double mutants are taller and develop more inflorescence shoots and flowers. Further analysis revealed that developmental arrest in the lox3 lox4 inflorescence occurs with the production of an abnormal carpelloid flower. This distinguishes lox3 lox4 mutants from the wild type where developmentally typical flower buds are the terminal inflorescence structures observed in both the laboratory and in nature. Our studies of lox3 lox4 as well as other jasmonic acid biosynthesis and perception mutants show that this plant hormone is not only required for male fertility but also involved in global proliferative arrest.

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Abstract:During my doctoral research, I focused on deciphering the interactions between sea-level and climate change during the Late Barremian-Early Aptian, their expression in the Tethys basin and in the Helvetic carbonate platform. The research highlights are summarized here in three points: In the Helvetic Alps, the transition between the Lower Schrattenkalk (Upper Barremian) and the Rawil Member (Lowermost Aptian) is characterized by a change from a predominantly photozoan to a heterozoan carbonate-producing system, which coincides in time with a general increase in detrital and nutrient input. The clay mineral record shows the appearance of kaolinite within the Rawil Member, whereas this mineral is absent from the uppermost Lower and lowermost Upper Schrattenkalk Members. This indicates the installation of a warmer and more humid climate during this time period. A negative peak in 513C is recorded at the top of the Lower Schrattenkalk Member, and correlates with the well-known negative excursion of -l%o occurring in other basins and dated as latest Barremian, thus confirming a latest Barremian and earliest Aptian age for the Lower Schrattenkalk and Rawil Members, respectively. Furthermore, a sequence stratigraphie framework has been defined for the Rawil Member, based on both the ecology of faunal and floral assemblages, and their palaeoenvironmental interpretation, as well as on the stacking pattern of limestone beds observed during field prospection. The presence of a sequence boundary is postulated near the top of the Lower Schrattenkalk Member, which is correlated with the earliest Aptian SbAl defined in Vercors (France). The SbAl is characterized by a maximum of proximal assemblages and by the disappearance of several benthic foraminiferal species. Within the Rawil Member itself, the stacking pattern and microfacies trends are interpreted to represent the TST of the first Aptian sequence. With regards to the pelagic setting in the Tethyan realm, I investigated the Gorgo a Cerbara section (central Italy). There, thin organic-rich layers occur episodically in pelagic carbonates of the upper Barremian portion of the Maiolica Formation. They are associated with high Corg:Ptot ratios, which indicate the presence of intermittent dysoxic to anoxic conditions. Coarse correlations are also observed between TOC, Ρ and biogenic silica contents, indicating links between Ρ availability, productivity, and organic matter preservation. The corresponding 813Ccarb and δ180 records remain, however, quite stable, indicating that these brief periods of enhanced TOC preservation did not have sufficient impact on the marine carbon household to deviate 6,3C records, and are probably not the consequence of major climate change. On the other hand, organic-rich layers become more frequent around the Barremian-Aptian boundary in both pelagic and hemi-pelagic environments (Gorgo a Cerbara and La Bédoule, France), which are correlated with negative excursions in 6l3Ccarb and 613Corg records. During the earliest Aptian, at Gorgo a Cerbara, the frequency of organic-rich intervals progressively increases and redox-sensitive trace-element enrichments become more frequent, until the highest TOC-enriched level just below the "Livello Selli", indicator of Oceanic Anoxic Event la (OAEla). The latter is associated with the well-known negative spike in 613Ccarb and S,3Corg records, a diminution in the δ,80 record interpreted as the consequence of a wanning interval, an important peak in Ρ accumulation and high Cor::Ptot ratios indicating the prevalence of anoxic conditions. The Selli Level (OAEla) documents a general cooling phase and coincides with maximum RSTE enrichments as well as high Corg:Ptot ratios, which confirm the importance of anoxic conditions during OAE1 a at this site.During the Early Aptian, environmental change on the platform is expressed by orbitolinids proliferation that may be induced by both climate change and sea-level rise. In the basin, the successive black shales horizons from the Late Barremian until the OAE la are interpreted as the progressive impact of palaeoenvironmental change probably linked to the formation of the Ontong- Java plate-basalt plateau.RésuméCe travail de thèse a permis d'investiguer les interactions entre les variations du niveau marin et les changements climatiques sur la plate-forme helvétique ainsi qu'en domaine pélagique à la limite Barrémien-Aptien (Crétacé).Dans les Alpes helvétiques, la limite Barrémien-Aptien est marquée par la transition du Schrattenkalk inférieur, caractérisé par des carbonates photozaires, au Membre de Rawil caractérisé par des carbonates héterozoaires. Cette transition est marquée par une arrivée massive d'éléments détritiques et un apport de nutriments ayant entraîné la prolifération de foraminifères agglutinés tels que les orbitolines. L'analyse des minéraux argileux indique l'apparition de la kaolinite durant le Membre de Rawil, interprétée comme l'installation d'un climat plus chaud et humide. Un pic négatif en 513C est enregistré au sommet du Schrattenkalk inférieur correspond à l'excursion négative de -1%0 bien connue en domaine pélagique et datée comme Barrémien terminal. Cette corrélation apporte un contrôle chronostratigraphique supplémentaire permettant de dater le Schrattenkalk inférieur du Barrémien sup. et le Membre de Rawil de l'Aptien inf. D'autre part, une étude stratigraphique, basée sur des observations de terrain et sur l'interprétation d'assemblages floristiques et faunistiques en terme de paléoenvironnement a permis de mettre en évidence une limite de séquence au sommet du Schrattenkalk inf., corrélable avec la SbAl définie dans le Vercors. Durant la mise en place du Membre de Rawil, l'évolution des microfaciès est interprétée comme le « Transgressive System Tract » de la première séquence aptienne.En domaine pélagique, de minces couches riches en matière organique (MO) apparaissent dès le Barrémien sup. dans la coupe de Gorgo a Cerbara (Italie). Elles sont associées à un ratio C:P élevé indiquant des conditions épisodiquement dysoxiques à anoxiques. De plus, une corrélation nette entre Carbone Organique Total (TOC), phosphore (P) et silice biogénique est observée correspondant à un lien entre Ρ disponible, productivité et préservation de la MO. Pourtant, dans le même temps, le ÔI3C et le δ1βΟ restent constants indiquant des conditions environnementales stables et un cycle du carbone non perturbé par la préservation de MO qui ne serait pas la conséquence d'un changement climatique global mais juste d'un effet local.Ala limite Barrémien-Aptien, en domaine hémi-pélagique (La Bédoule, France) et pélagique (Gorgo a Cerbara), les couches riches en MO sont plus fréquentes et plus épaisses, elles se sont déposées en même temps qu'un pic négatif en 513CCARB et ô13Coib probablement dû à un épisode volcanique. A l'Aptien inf. le TOC des niveaux riches en MO augmente progressivement en même temps que la teneur en éléments traces jusqu'au dernier enrichissement avant l'événement anoxique océanique la (OAE la) correspondant au « niveau critique inf. », indiquant des conditions anoxiques moins restreintes. Celui-ci est également caractérisé par le fameux pic négatif en Ô13C (C3), une diminution du δ180 interprétée comme un réchauffement, par un pic en Ρ et un ratio C:P élevé. L'OAE 1 a, quant à lui, enregistre un refroidissement et coïncide avec le maximum en éléments traces ainsi qu'un fort ratio C:P mettant en valeur l'importance des conditions anoxiques pendant 1ΌΑΕ la dans cette coupe alors qu'aucune perturbation n'est enregistrés à La Bédoule probablement à cause de conditions paléogéographiques locales.Durant l'Aptien inf., les changements environnementaux sur la plate-forme se marquent par la prolifération d'orbitolines due à un changement climatique et une hausse du niveau marin. En domaine profond, la succession de niveaux riches en MO du Barrémien sup. jusqu'à l'OAE la documente l'impact progressif de changements paléoenvironnementaux, probablement liés à la formation du plateau d'Ontong Java à l'ouest de l'océan Pacifique.

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Development and environmental issues of small cities in developing countries have largely been overlooked although these settlements are of global demographic importance and often face a "triple challenge"; that is, they have limited financial and human resources to address growing environmental problems that are related to both development (e.g., pollution) and under-development (e.g., inadequate water supply). Neoliberal policy has arguably aggravated this challenge as public investments in infrastructure generally declined while the focus shifted to the metropolitan "economic growth machines". This paper develops a conceptual framework and agenda for the study of small cities in the global south, their environmental dynamics, governance and politics in the current neoliberal context. While small cities are governed in a neoliberal policy context, they are not central to neoliberalism, and their (environmental) governance therefore seems to differ from that of global cities. Furthermore, "actually existing" neoliberal governance of small cities is shaped by the interplay of regional and local politics and environmental situations. The approach of urban political ecology and the concept of rural-urban linkages are used to consider these socio-ecological processes. The conceptual framework and research agenda are illustrated in the case of India, where the agency of small cities in regard to environmental governance seems to remain limited despite formal political decentralization.

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Mutations in PLA2G6 gene have variable phenotypic outcome including infantile neuroaxonal dystrophy, atypical neuroaxonal dystrophy, idiopathic neurodegeneration with brain iron accumulation and Karak syndrome. The cause of this phenotypic variation is so far unknown which impairs both genetic diagnosis and appropriate family counseling. We report detailed clinical, electrophysiological, neuroimaging, histologic, biochemical and genetic characterization of 11 patients, from 6 consanguineous families, who were followed for a period of up to 17 years. Cerebellar atrophy was constant and the earliest feature of the disease preceding brain iron accumulation, leading to the provisional diagnosis of a recessive progressive ataxia in these patients. Ultrastructural characterization of patients' muscle biopsies revealed focal accumulation of granular and membranous material possibly resulting from defective membrane homeostasis caused by disrupted PLA2G6 function. Enzyme studies in one of these muscle biopsies provided evidence for a relatively low mitochondrial content, which is compatible with the structural mitochondrial alterations seen by electron microscopy. Genetic characterization of 11 patients led to the identification of six underlying PLA2G6 gene mutations, five of which are novel. Importantly, by combining clinical and genetic data we have observed that while the phenotype of neurodegeneration associated with PLA2G6 mutations is variable in this cohort of patients belonging to the same ethnic background, it is partially influenced by the genotype, considering the age at onset and the functional disability criteria. Molecular testing for PLA2G6 mutations is, therefore, indicated in childhood-onset ataxia syndromes, if neuroimaging shows cerebellar atrophy with or without evidence of iron accumulation.

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While the morphological and electrophysiological changes underlying diabetic peripheral neuropathy (DPN) are relatively well described, the involved molecular mechanisms remain poorly understood. In this study, we investigated whether phenotypic changes associated with early DPN are correlated with transcriptional alterations in the neuronal (dorsal root ganglia [DRG]) or the glial (endoneurium) compartments of the peripheral nerve. We used Ins2(Akita/+) mice to study transcriptional changes underlying the onset of DPN in type 1 diabetes mellitus (DM). Weight, blood glucose and motor nerve conduction velocity (MNCV) were measured in Ins2(Akita/+) and control mice during the first three months of life in order to determine the onset of DPN. Based on this phenotypic characterization, we performed gene expression profiling using sciatic nerve endoneurium and DRG isolated from pre-symptomatic and early symptomatic Ins2(Akita/+) mice and sex-matched littermate controls. Our phenotypic analysis of Ins2(Akita/+) mice revealed that DPN, as measured by reduced MNCV, is detectable in affected animals already one week after the onset of hyperglycemia. Surprisingly, the onset of DPN was not associated with any major persistent changes in gene expression profiles in either sciatic nerve endoneurium or DRG. Our data thus demonstrated that the transcriptional programs in both endoneurial and neuronal compartments of the peripheral nerve are relatively resistant to the onset of hyperglycemia and hypoinsulinemia suggesting that either minor transcriptional alterations or changes on the proteomic level are responsible for the functional deficits associated with the onset of DPN in type 1 DM.

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Biofuels are considered as a promising substitute for fossil fuels when considering the possible reduction of greenhouse gases emissions. However limiting their impacts on potential benefits for reducing climate change is shortsighted. Global sustainability assessments are necessary to determine the sustainability of supply chains. We propose a new global criterion based framework enabling a comprehensive international comparison of bioethanol supply chains. The interest of this framework is that the selection of the sustainability indicators is qualified on three criterions: relevance, reliability and adaptability to the local context. Sustainability issues have been handled along environmental, social and economical issues. This new framework has been applied for a specific issue: from a Swiss perspective, is locally produced bioethanol in Switzerland more sustainable than imported from Brazil? Thanks to this framework integrating local context in its indicator definition, Brazilian production of bioethanol is shown as energy efficient and economically interesting for Brazil. From a strictly economic point of view, bioethanol production within Switzerland is not justified for Swiss consumption and questionable for the environmental issue. The social dimension is delicate to assess due to the lack of reliable data and is strongly linked to the agricultural policy in both countries. There is a need of establishing minimum sustainability criteria for imported bioethanol to avoid unwanted negative or leakage effects.