2,065 research outputs found
Dispersal in Mastomys natalensis mice: use of fine-scale genetic analyses for pest management
Mastomys natalensis is the major pest rodent in sub-Saharan Africa. In this study, population genetic techniques were used to gain new insights into its dispersal behaviour, a critical parameter in pest management. Using 11 microsatellites, 272 individuals from a 300 ha area in Tanzania were genotyped. Genetic diversity was high, with no isolation by distance and little differentiation between field plots far apart, indicating a large effective population size and high dispersal rates in agreement with ecological observations. On the other hand, genetic differentiation between nearby field plots, isolation by distance within a single field plot and kin clustering were also observed. This apparent contradiction may be explained by yearly founder effects of a small number of breeding individuals per square area, which is consistent with the presence of linkage disequilibrium. An alternative, not mutually exclusive explanation is that there are both dispersing and sedentary animals in the population. The low-density field plots were characterized by low relatedness and small genetic distances to other field plots, indicating a high turnover rate and negative density-dependent dispersal. In one field plot female-biased dispersal was observed, which may be related to inbreeding avoidance or female competition for resources. Most juveniles appeared to be local recruits, but they did not seem to stay in their native area for more than two months. Finally, possible implications for pest management are discusse
Product liability in a world of automated products and digital distribution channels
The article examines some of the legal challenges brought about by automation and digitalization. The specific focus is on product liability rules. The article examines the way in which automation may challenge both the traditional concept of a âproductâ and of a âdefectâ in the product liability directive and explores the extent to which a digital platform, used for distribution of products, could be regarded a âproducerâ within the meaning of the product liability directive.O artigo analisa alguns dos desafios jurĂdicos criados pela automação e digitalização, especificamente no domĂnio da responsabilida-de do produtor. Averiguam-se os desafios que a automação coloca aos conceitos tradicionais de âprodutoâ e de âdefeitoâ na Diretiva sobre Responsabilidade pelo Produto, bem como a questĂŁo de saber se uma pla-taforma digital usada para distribuição de produtos poderĂĄ enquadrar-se no conceito de âprodutorâ na acepção dessa mesma Diretiva
Vicarious Liability in Groups of Companies and in Supply Chains - Is Competition Law Leading the Way?
The article discusses the concept of vicarious liability in the area of competition law. It argues that this concept is to some extent embedded in the concept of the undertaking under competition law with the consequence that parent companies â under certain conditions â can be held liable for competition law infringements committed by subsidiaries. The liability can be termed âvicariousâ because it is imposed regardless of whether the parent company was involved in or ought to have had any knowledge of the competition law infringements committed by the subsidiary. Whereas such liability has until recently only been imposed for administrative fines, the Skanska decision changes this. Following this decision it must be assumed that parent companies can also be held vicariously liable for civil liability incurred by a subsidiary. It is pointed out that it is a separate question whether the Akzo-presumption rule, established with regard to the imposition of fines for competition law infringements, can also be applied in a pure civil liability case concerning parental liability. Next, the article discusses whether the results reached in the area of competition law can be transferred to other areas of the law. In this regard, the article analyses recent case law with regard to parental liability for workersâ injuries and environmental damage and compares these areas of the law to competition law. Finally, the article discusses whether the concept of the undertaking can be extended to apply also in situations where companies are not tied by ownership but by contract. In this regard the article focuses on the (possibly) emerging concept of supply chain liability
Vertical plate motions in the West Siberian Basin and Northern Europe as indicators of mantle-induced dynamic topography
Motion of the lithospheric plates is a reflection of the convective circulation of the Earthâs mantle. Plate divergence is attributed to the mantle upwellings, while plate convergence to the mantleâs downwellings. In addition to the horizontal movement, plates move vertically. Vertical plate motions are documented both at the tectonic boundaries and in the plate interior. The marginal vertical motions can be explained by the changes of the stress state in the plate boundary setting. Yet, a mechanism responsible for the intra-plate vertical motions still remains unclear. Understanding this mechanism would shed the light on the nature of anomalous topographic features and improve the knowledge of the poorly constrained Earthâs mantle parameters. Moreover, it would have implications for minimizing the risks associated with explorations of natural energy resources.
In this work we study the character of intraplate vertical motions and their driving forces in the West Siberian Basin (WSB) and Northern Europe. We begin by constraining the tectonic subsidence history of the WSB. The WSBâs sedimentary cover represents an archive the basinâs vertical motions for the last 250 million years. Due to the basinâs intraplate location and a large scale, it serves as a perfect location to study the vertical motions isolated from the effects of plate boundary stresses. Our analysis shows that the WSB experienced anomalous subsidence interrupted by repeated episodes of uplift, consistent with uplift events reported in the Barents Sea and at the North Atlantic passive margin.
We extend our study by exploring the vertical motions in the North Western Europe and the North Atlantic. To illustrate the regional topographic evolution, we construct the digital continent-scale erosional surface maps for 5 stratigraphic boundaries of Cenozoic. The maps reveal that Northern Europe experienced increased erosion in the late Paleocene â late Eocene and in the Miocene. These time intervals also correspond to the episodes of increased North Atlantic spreading velocity. Accordingly, our work shows a strong agreement between the two trends. In addition, we find that these results agree with the dynamic topography trend inferred by the output of a mantle convection model. We connect these findings through a common mantle-related mechanism.
We suggest that observed trend may indicate a fast, plume-fed flow in the thin asthenospheric channel beneath Northern Europe. The topographic signal may reflect a mantle flow driven by the pressure gradient related to Iceland. Such flow serves as a link between the horizontal and vertical plate motions and could have implications for the paleo-topographic and basin development studies in Europe and in other regions
Stochastic fiber dynamics in a spatially semi-discrete setting
We investigate a spatially discrete surrogate model for the dynamics of a
slender, elastic, inextensible fiber in turbulent flows. Deduced from a
continuous space-time beam model for which no solution theory is available, it
consists of a high-dimensional second order stochastic differential equation in
time with a nonlinear algebraic constraint and an associated Lagrange
multiplier term. We establish a suitable framework for the rigorous formulation
and analysis of the semi-discrete model and prove existence and uniqueness of a
global strong solution. The proof is based on an explicit representation of the
Lagrange multiplier and on the observation that the obtained explicit drift
term in the equation satisfies a one-sided linear growth condition on the
constraint manifold. The theoretical analysis is complemented by numerical
studies concerning the time discretization of our model. The performance of
implicit Euler-type methods can be improved when using the explicit
representation of the Lagrange multiplier to compute refined initial estimates
for the Newton method applied in each time step.Comment: 20 pages; typos removed, references adde
Vertical plate motions in the West Siberian Basin and Northern Europe as indicators of mantle-induced dynamic topography
Motion of the lithospheric plates is a reflection of the convective circulation of the Earthâs mantle. Plate divergence is attributed to the mantle upwellings, while plate convergence to the mantleâs downwellings. In addition to the horizontal movement, plates move vertically. Vertical plate motions are documented both at the tectonic boundaries and in the plate interior. The marginal vertical motions can be explained by the changes of the stress state in the plate boundary setting. Yet, a mechanism responsible for the intra-plate vertical motions still remains unclear. Understanding this mechanism would shed the light on the nature of anomalous topographic features and improve the knowledge of the poorly constrained Earthâs mantle parameters. Moreover, it would have implications for minimizing the risks associated with explorations of natural energy resources.
In this work we study the character of intraplate vertical motions and their driving forces in the West Siberian Basin (WSB) and Northern Europe. We begin by constraining the tectonic subsidence history of the WSB. The WSBâs sedimentary cover represents an archive the basinâs vertical motions for the last 250 million years. Due to the basinâs intraplate location and a large scale, it serves as a perfect location to study the vertical motions isolated from the effects of plate boundary stresses. Our analysis shows that the WSB experienced anomalous subsidence interrupted by repeated episodes of uplift, consistent with uplift events reported in the Barents Sea and at the North Atlantic passive margin.
We extend our study by exploring the vertical motions in the North Western Europe and the North Atlantic. To illustrate the regional topographic evolution, we construct the digital continent-scale erosional surface maps for 5 stratigraphic boundaries of Cenozoic. The maps reveal that Northern Europe experienced increased erosion in the late Paleocene â late Eocene and in the Miocene. These time intervals also correspond to the episodes of increased North Atlantic spreading velocity. Accordingly, our work shows a strong agreement between the two trends. In addition, we find that these results agree with the dynamic topography trend inferred by the output of a mantle convection model. We connect these findings through a common mantle-related mechanism.
We suggest that observed trend may indicate a fast, plume-fed flow in the thin asthenospheric channel beneath Northern Europe. The topographic signal may reflect a mantle flow driven by the pressure gradient related to Iceland. Such flow serves as a link between the horizontal and vertical plate motions and could have implications for the paleo-topographic and basin development studies in Europe and in other regions
A systematic review of association between organic environmental pollutants and testicular cancer
Objective There is an increasing incidence of testicular cancer in the world, which cannot be explained by factors as increasing life expectancy as this type of cancer typically affects young men. Particularly in certain countries that also score high on the Human Development Index (HDI) the incidence of testicular cancer is high, and as countries increase the HDI so does the incidence of testicular cancer. It is hypothesized that something introduced in the environment may induce with testicular cancer, like organic environmental pollutants. The research question for this review was articulated as: âA systematic review of association between organic environmental pollutants and testicular cancerâ
Methods A systematic literature in PubMed search was conducted on the 23rd of October 2019. The search involved articles published the last ten years. Inclusion criteria were articles reviewing the effects organic environmental pollutants have on cell mechanisms that could be linked to the development of testicular cancer, or incidents that could be linked to exposure. Articles involving cancer treatment, or other effects organic environmental pollutants have on human health were excluded. After sorting out the relevant articles there were a total of 28 articles to be used in this systematic review.
Results After a selection process the literature search yielded 20 articles that were included in this research, most of which were reviews. The articles presented conflicting conclusions, while some supported the hypothesis of an association between organic environmental pollutants and testicular cancer, others did not imply association.
Conclusion There has been done too little research on this field to conclude whether organic environmental pollutants have a causal effect on the development of testicular cancer. However, some articles suggested that there could be an association. Especially cell studies demonstrated an effect of organic environmental pollutants on cell components. Further research on the field of environmental pollutants and the development of testicular cancer is therefore needed
An exploration of the effects of tDCS to Supplementary Motor Complex on measures of inhibitory control: Implications for Touretteâs syndrome
Inhibitory control (IC) depends on a cortico-subcortical network, with downstream effects on the primary motor cortex (M1). Hyperexcitability in M1 has been proposed to impair IC, a state associated with tics in patients with Touretteâs syndrome (TS). Anodal Transcranial Direct Current Stimulation (tDCS) applied over the Supplementary Motor Complex (SMC) in order to decrease M1 excitability has improved IC in healthy subjects, while increased tics in patients. In parallel, cathodal tDCS to increase M1 excitability have reduced tics, but impaired IC in healthy adults. Aiming to explore these contradictory findings, we analyzed the effects of anodal, cathodal, and sham tDCS applied to the SMC on measures of IC in young, healthy adults. M1 excitability was monitored with Transcranial Magnetic Stimulation (TMS) and IC was measured from performance on the Anticipatory Response Inhibition Task. The results revealed no change in IC following tDCS. However, we observed a tDCS-induced change in M1 excitability. This suggest that tDCS applied to SMC mainly affects M1 excitability via the cortico-cortical pathway, without engaging the subcortical network important for IC. We also observed an individual response variability to tDCS, showing unreliable directions in excitatory shifts. Overall, we suggest that the puzzling effect on tics following tDCS to SMC could result from direct cortical effects from SMC, not from the involvement of the inhibitory subcortical network. Without undermining the effect of tDCS, we highlight the response variability limiting the methods reliability in the investigation of cognitive abilities and clinical symptoms.Masteroppgave i psykologiMAPSYK360MAPS-PSYKINTL-KMDINTL-MEDINTL-HFINTL-SVINTL-PSYKINTL-MNINTL-JU
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