934 resultados para migration of rhizobia
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The migration of liquids in porous media, such as sand, has been commonly considered at high saturation levels with liquid pathways at pore dimensions. In this letter we reveal a low saturation regime observed in our experiments with droplets of extremely low volatility liquids deposited on sand. In this regime the liquid is mostly found within the grain surface roughness and in the capillary bridges formed at the contacts between the grains. The bridges act as variable-volume reservoirs and the flow is driven by the capillary pressure arising at the wetting front according to the roughness length scales. We propose that this migration (spreading) is the result of interplay between the bridge volume adjustment to this pressure distribution and viscous losses of a creeping flow within the roughness. The net macroscopic result is a special case of non-linear diffusion described by a superfast diffusion equation (SFDE) for saturation with distinctive mathematical character. We obtain solutions to a moving boundary problem defined by SFDE that robustly convey a time power law of spreading as seen in our experiments.
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Global hydrographic and air–sea freshwater flux datasets are used to investigate ocean salinity changes over 1950–2010 in relation to surface freshwater flux. On multi-decadal timescales, surface salinity increases (decreases) in evaporation (precipitation) dominated regions, the Atlantic–Pacific salinity contrast increases, and the upper thermocline salinity maximum increases while the salinity minimum of intermediate waters decreases. Potential trends in E–P are examined for 1950–2010 (using two reanalyses) and 1979–2010 (using four reanalyses and two blended products). Large differences in the 1950–2010 E–P trend patterns are evident in several regions, particularly the North Atlantic. For 1979–2010 some coherency in the spatial change patterns is evident but there is still a large spread in trend magnitude and sign between the six E–P products. However, a robust pattern of increased E–P in the southern hemisphere subtropical gyres is seen in all products. There is also some evidence in the tropical Pacific for a link between the spatial change patterns of salinity and E–P associated with ENSO. The water cycle amplification rate over specific regions is subsequently inferred from the observed 3-D salinity change field using a salt conservation equation in variable isopycnal volumes, implicitly accounting for the migration of isopycnal surfaces. Inferred global changes of E–P over 1950–2010 amount to an increase of 1 ± 0.6 % in net evaporation across the subtropics and an increase of 4.2 ± 2 % in net precipitation across subpolar latitudes. Amplification rates are approximately doubled over 1979–2010, consistent with accelerated broad-scale warming but also coincident with much improved salinity sampling over the latter period.
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Climatic and land use changes have significant consequences for the distribution of tree species, both through natural dispersal processes and following management prescriptions. Responses to these changes will be expressed most strongly in seedlings near current species range boundaries. In northern temperate forest ecosystems, where changes are already being observed, ectomycorrhizal fungi contribute significantly to successful tree establishment. We hypothesised that communities of fungal symbionts might therefore play a role in facilitating, or limiting, host seedling range expansion. To test this hypothesis, ectomycorrhizal communities of interior Douglas-fir and interior lodgepole pine seedlings were analysed in a common greenhouse environment following growth in five soils collected along an ecosystem gradient. Currently, Douglas-fir’s natural distribution encompasses three of the five soils, whereas lodgepole pine’s extends much further north. Host filtering was evident amongst the 29 fungal species encountered: 7 were shared, 9 exclusive to Douglas-fir and 13 exclusive to lodgepole pine. Seedlings of both host species formed symbioses with each soil fungal community, thus Douglas-fir did so even where those soils came from outside its current distribution. However, these latter communities displayed significant taxonomic and functional differences to those found within the host distribution, indicative of habitat filtering. In contrast, lodgepole pine fungal communities displayed high functional similarity across the soil gradient. Taxonomic and/or functional shifts in Douglas-fir fungal communities may prove ecologically significant during the predicted northward migration of this species; especially in combination with changes in climate and management operations, such as seed transfer across geographical regions for forestry purposes.
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Predicting the evolution of ice sheets requires numerical models able to accurately track the migration of ice sheet continental margins or grounding lines. We introduce a physically based moving point approach for the flow of ice sheets based on the conservation of local masses. This allows the ice sheet margins to be tracked explicitly and the waiting time behaviours to be modelled efficiently. A finite difference moving point scheme is derived and applied in a simplified context (continental radially-symmetrical shallow ice approximation). The scheme, which is inexpensive, is validated by comparing the results with moving-margin exact solutions and steady states. In both cases the scheme is able to track the position of the ice sheet margin with high precision.
Resumo:
Predicting the evolution of ice sheets requires numerical models able to accurately track the migration of ice sheet continental margins or grounding lines. We introduce a physically based moving-point approach for the flow of ice sheets based on the conservation of local masses. This allows the ice sheet margins to be tracked explicitly. Our approach is also well suited to capture waiting-time behaviour efficiently. A finite-difference moving-point scheme is derived and applied in a simplified context (continental radially symmetrical shallow ice approximation). The scheme, which is inexpensive, is verified by comparing the results with steady states obtained from an analytic solution and with exact moving-margin transient solutions. In both cases the scheme is able to track the position of the ice sheet margin with high accuracy.
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ISO19156 Observations and Measurements (O&M) provides a standardised framework for organising information about the collection of information about the environment. Here we describe the implementation of a specialisation of O&M for environmental data, the Metadata Objects for Linking Environmental Sciences (MOLES3). MOLES3 provides support for organising information about data, and for user navigation around data holdings. The implementation described here, “CEDA-MOLES”, also supports data management functions for the Centre for Environmental Data Archival, CEDA. The previous iteration of MOLES (MOLES2) saw active use over five years, being replaced by CEDA-MOLES in late 2014. During that period important lessons were learnt both about the information needed, as well as how to design and maintain the necessary information systems. In this paper we review the problems encountered in MOLES2; how and why CEDA-MOLES was developed and engineered; the migration of information holdings from MOLES2 to CEDA-MOLES; and, finally, provide an early assessment of MOLES3 (as implemented in CEDA-MOLES) and its limitations. Key drivers for the MOLES3 development included the necessity for improved data provenance, for further structured information to support ISO19115 discovery metadata export (for EU INSPIRE compliance), and to provide appropriate fixed landing pages for Digital Object Identifiers (DOIs) in the presence of evolving datasets. Key lessons learned included the importance of minimising information structure in free text fields, and the necessity to support as much agility in the information infrastructure as possible without compromising on maintainability both by those using the systems internally and externally (e.g. citing in to the information infrastructure), and those responsible for the systems themselves. The migration itself needed to ensure continuity of service and traceability of archived assets.
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Periodontal disease (PD) progression involves the selective leukocyte infiltration into periodontium, supposedly mediated by the chemokine/chemokine receptor system. In this study, we investigated the role of chemokine receptor CCR5 in the immunoregulation of experimental PD in C57BL/6 (WT) and CCR5KO mice. Aggregatibacter actinomycetem comitans infection triggered the chemoattraction of distinct CCR5+ leukocyte subpopulations (determined by flow cytometry): CCR5+F4/80+ leukocytes, which co-express CD14, CCR2, TNF-alpha, and IL-1 beta, indicative of activated macrophages; and CCR5+CD4+ cells, which co-express CXCR3, IFN-gamma, and RANKL, indicative of Th1 lymphocytes, therefore comprising pro-osteoclastic and osteoclastogenic cell subsets, respectively. CCR5KO mice presented a lower PD severity (lower inflammation and alveolar bone loss) when compared with the WT strain, since the migration of F4/80+, TNF-alpha+, CD4+, and RANKL+ cells specifically decreased due to the lack of CCR5. Also, ELISA analysis demonstrated that the production of TNF-alpha, IL-1 beta, IL-6, IFN-gamma, and RANKL in periodontal tissues was significantly decreased in the CCR5KO strain. The periodontal bacterial load and antimicrobial patterns were unaltered in CCR5KO mice. Our results demonstrate that the chemokine receptor is involved in the migration of distinct leukocyte subpopulations throughout experimental PD, being a potential target for therapeutic intervention in PD.
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The aim of this thesis is to describe and analyze the geographical distribution of everyday criminality in the town of Borlänge during the year 2002 and to analyze which measures to be taken in the physical social planning to decrease this everyday criminality there. The term everyday criminality is here to be understood as those categories of crime that appear most frequently in the records of reports to the police every year. Here two kinds of crime have been in focus, thefts from cars and office burglary.In fulfilling this aim two main questions have been answered. The first one is how the everyday criminality was distributed geographically in the town of Borlänge during the year 2002. The second one is which measures to be taken in the physical social planning to decrease this everyday criminality in the town of Borlänge.In order to answer the first question a spatial autocorrelation analysis, Local Moran LISA has been used. This method is based on the measurement Moran´s I and shows the spatial autocorrelation for every single location. To answer the second question three different theories of crime prevention through environmental design have been studied and applied in the analysis. These are Jane Jacobs’ ideas about ”the living city”, Oscar Newman´s ideas about ”defensible space” and Ronald V. Clarke´s theories about crime prevention.The major conclusions that can be drawn from this thesis are that the risk of being exposed to thefts from cars, during the analyzed time period, was highest in Centrum and Hagalund and their surroundings. The lowest risk of being exposed to this type of crime was found in Domnarvet and Islingby, during the year 2002. The highest risk of being a victim of the crime office burglary was found in Hagalund and its surroundings and in the single area of Kvarnsveden. The corresponding lowest risk was found in Lergärdet and its surroundings and in Norra Backa and Kupolen. The measures that should be taken in order to decrease these types of criminality can be divided into overall changes and place-specific changes. When it comes to the crime thefts from cars a more attractive central business district, a better view of parking lots from nearby buildings, dividing of larger parking lot zones into smaller ones, migration of hidden parking lots and stronger access control to parking lots where problems with this kind of crime have occurred have been suggested as overall changes. The corresponding place-specific changes are to remove vegetation that is blocking the view, better lighting and to put up signs with information about increased risk of exposure to crime at parking lots with the most problems. To decrease the amount of office burglaries overall changes as to create a better view of the area from nearby surroundings, move bigger office compartments or divide them into smaller units, rebuild characteristic buildings and increase security by strengthening the access control to offices with these kinds of problems could be useful. Finally there are possibilities to decrease office burglary by using place-specific measures as surveillance cameras combined with signs containing information about these, high fences and better lighting around the buildings where a higher risk of being exposed to this kind of criminality is present.
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Cloud computing innebär användning av datorresurser som är tillgängliga via ett nätverk, oftast Internet och är ett område som har vuxit fram i snabb takt under de senaste åren. Allt fler företag migrerar hela eller delar av sin verksamhet till molnet. Sogeti i Borlänge har behov av att migrera sina utvecklingsmiljöer till en molntjänst då drift och underhåll av dessa är kostsamma och tidsödande. Som Microsoftpartners vill Sogeti använda Microsoft tjänst för cloud computing, Windows Azure, för detta syfte. Migration till molnet är ett nytt område för Sogeti och de har inga beskrivningar för hur en sådan process går till. Vårt uppdrag var att utveckla ett tillvägagångssätt för migration av en IT-lösning till molnet. En del av uppdraget blev då att kartlägga cloud computing, dess beståndsdelar samt vilka för- och nackdelar som finns, vilket har gjort att vi har fått grundläggande kunskap i ämnet. För att utveckla ett tillvägagångssätt för migration har vi utfört flera migrationer av virtuella maskiner till Windows Azure och utifrån dessa migrationer, litteraturstudier och intervjuer dragit slutsatser som mynnat ut i ett generellt tillvägagångssätt för migration till molnet. Resultatet har visat att det är svårt att göra en generell men samtidigt detaljerad beskrivning över ett tillvägagångssätt för migration, då scenariot ser olika ut beroende på vad som ska migreras och vilken typ av molntjänst som används. Vi har dock utifrån våra erfarenheter från våra migrationer, tillsammans med litteraturstudier, dokumentstudier och intervjuer lyft vår kunskap till en generell nivå. Från denna kunskap har vi sammanställt ett generellt tillvägagångssätt med större fokus på de förberedande aktiviteter som en organisation bör genomföra innan migration. Våra studier har även resulterat i en fördjupad beskrivning av cloud computing. I vår studie har vi inte sett att någon tidigare har beskrivit kritiska framgångsfaktorer i samband med cloud computing. I vårt empiriska arbete har vi dock identifierat tre kritiska framgångsfaktorer för cloud computing och i och med detta täckt upp en del av kunskapsgapet där emellan.
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The unauthorized migrants in the Swedish construction sector – a study in the policy of deportation 1990–2004 The unauthorized migration of construction workers to Sweden increased during the 1990s, especially at the end of the decade. The migrants often came from Poland and the Baltic states. The aim of this article is to examine this change of the migration pattern to Sweden and how the Swedish Building Workers Union responded to this new situation. I examine how the Building Workers Union cooperated with the Police authorities to find, capture and deport unauthorized migrants. A conclusion is that the Building Workers Union has not adopted a more inclusionary strategy towards unauthorized migrants, as have trade unions in Spain and US. The main strategy has instead been to try to restrict this migration. One explanation of this is that the Building Workers Union is a strong and well organized trade union. It didn’t perceive of unauthorized migrants as potential new members, but as a threat to wages and work conditions. Another explanation is that it has been able to restrict migration in the past. This may contribute to making demands for restrictions an attractive strategy in the present even when the possibilities of succeeding with this have diminished.
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Nowadays, the free software has been presented as an alternative to the acquisition structure of proprietors¿ software licenses, being adopted by a large number of companies. This study presents the analysis, through a case study, of a project of proprietors¿ software migration for free platforms. The main purpose was to identify decisive factors of success in the adoption of free softwares for private companies. For this, was used the single case methodology of study, presented by Yin (2005). The theoretical referential approaches issues related to the definitions and the historic of the free software, the resistance to information systems and the change resistance. The idea is to look for the fundamentals to support the researchers understanding of the situations observed in the field. The data found at this research was analyzed using a meta-frame, which has as the main point the Unified Theory of Acceptance and Use of Information Technology, developed by Venkatesh et al. (2003). Also, to complete this meta-frame, were used the Technology Acceptance Model, proposed by Davis (1989), and Interaction¿s Model of system and context of Use, developed by Markus (1983). The researche¿s result has been gotten by the analysis of documentation, interviews, questionnaires, direct observation and participant observation, that made possible the obtaining of valuable group of data on the researched subject. The result of this research allow the establishment of subsidies for the planning and development of project of proprietors¿ softwares migration for free softwares.
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o trabalho discute os fatores que condicionaram a migração de planos de beneficios entre os Fundos de Pensão localizados no Estado do Espírito Santo. O mais antigo modelo de plano de beneficios implantado no Brasil, o plano de beneficio definido, tem características bastante vantajosas aos participantes, pois as empresas patrocinadoras assumem os riscos de desequilíbrio do plano, e os beneficios futuros são assegurados aos participantes. O segundo modelo, mais recente no país, tem como característica principal o fato de que o participante assume os riscos do plano, e os beneficios futuros dependem de diversos fatores, como rentabilidade, tempo de participação, entre outros, deixando de existir garantia aos participantes. Apesar disso, os Fundos de Pensão tem implantado processos de migração de planos de beneficio definido para contribuição definida com sucesso. O texto procura identificar as razões e conseqüências da migração, estabelecendo correlações entre os dois modelos, identificando suas diferenças e semelhanças, o papel exercido pelas empresas patrocinadoras e a estratégia de convencimento dos participantes. Pretende-se que as reflexões sobre esse processo possam contribuir para que os Fundos de Pensão e outros pesquisadores interessados possam ter um nível maior de compreensão e fundamentação sobre o assunto.
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The final objective of this work will be to develop a study collating the theses defended for the historian Paul Kennedy and sociologist Domenico De Masi, presenting the ma in factors that influence in the process of migration of the jobs for the developed countries or in its maintenance in the countries in development, verifying if it has signals of flexibility in such process as reply to the fast technological development andl or the expansion of the "creative leisure". The present work has for purpose to search not them last and projected taxes of growth of work, but yes the factors that appear less in the threshold of related centuries XX and XXI to the human work and a possible route of migration of the existing jobs in the developed countries for the nations richest of the planet what it would lead, for consequence, to a still bigger inequality it enters the poor nations richest and, leading to a social collapse caused by the aggravation of the inequality in this distribution of income between the peoples.
Resumo:
A falta de profissionais com perfil e qualificação em tecnologia da informação (TI) é uma dificuldade enfrentada pelas empresas em geral, as quais investem crescentemente em TI e cada vez mais são dependentes e influenciadas pela tecnologia. Além dessa questão, observa-se que apesar das boas oportunidades de emprego no setor, a evasão nos cursos superiores de TI tem atingido patamares altíssimos, agravando ainda mais o problema da escassez por talentos qualificados. Assim, esta pesquisa estuda a migração dos profissionais de TI para outras áreas, fenômeno denominado turnaway, problema que agrava ainda mais a situação em que se encontra o setor de tecnologia da informação no mercado brasileiro, requerendo uma solução a curto prazo e merecendo uma exploração e discussão em profundidade. O objetivo principal deste estudo é, portanto, identificar as principais razões que explicam a intenção dos profissionais de TI em abandonar a área. Assim, foi realizada uma pesquisa explanatória, por meio de pesquisa bibliográfica e investigação empírica, aplicando-se questionários disponibilizados eletronicamente a profissionais de TI de diferentes empresas e áreas de atuação. A amostra utilizada teve 323 respondentes e os dados obtidos foram analisados estatisticamente via modelagem de equações estruturais. Como resultado, esta pesquisa mostrou que a transição de carreira na área de tecnologia da informação está intimamente associada ao dinamismo natural da área, às condições de trabalho que geram fadiga física e mental, e às restrições de crescimento profissional na área técnica, levando os profissionais de TI a uma insatisfação com a área que os faz buscar capacitação gerencial e novas experiências de trabalho, de modo a ampliar sua rede de relacionamento interpessoal e abrir oportunidades em diferentes campos de trabalho, possibilitando, desta forma, a migração dos mesmos para outras áreas que oferecem melhores condições de trabalho, maior reconhecimento e possibilidade de crescimento profissional.
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A Automação e o processo de Robotização vêm, cada vem mais, se tornando pauta nas discussões de centenas de indústrias brasileiras, onde a tendência clara e identificada é a de investimentos expressivos na melhoria de processos e produtos, por intermédio dessas tecnologias; com foco, sempre que possível, na nacionalização de equipamentos. O presente trabalho tem como objetivo avaliar o modelo proposto por Paul Kennedy (1993) com relação à tendência de Automação e Robotização nas Indústrias Mundiais, analisando o estudo realizado diante de uma economia emergente como a brasileira. Para tanto, foram pesquisadas empresas no Brasil, em diferentes segmentos industriais, o estado da arte em termos de tecnologia de automação e robótica aplicada a processos industriais, e sugerido um modelo diferente do idealizado originalmente por Kennedy. A análise do autor se baseou no teorema que, na matemática discreta, chamamos de “law of the excluded middle”, ou seja, segundo Kennedy, o Brasil estaria vivendo hoje uma migração gradual das indústrias para os países ricos. O Brasil é um exemplo de país industrializado, de economia emergente, que investe intensamente em processos automatizados, mas que não é classificado dentro do grupo desses países ricos. Através da pesquisa realizada será apresentado um novo modelo, no qual países emergentes como o Brasil têm acesso à tecnologia de ponta em automação e robótica, aplicando a mesma em seus processos industriais.