Adaptive FE-BE Coupling for Strongly Nonlinear Transmission Problems with Coulomb Friction

We analyze an adaptive finite element/boundary element procedure for scalar elastoplastic interface problems involving friction, where a nonlinear uniformly monotone operator such as the p-Laplacian is coupled to the linear Laplace equation on the exterior domain. The problem is reduced to a boundary/domain variational inequality, a discretized saddle point formulation of which is then solved using the Uzawa algorithm and adaptive mesh refinements based on a gradient recovery scheme. The Galerkin approximations are shown to converge to the unique solution of the variational problem in a suitable product of L^p- and L^2-Sobolev spaces.Comment: 27 pages, 3 figure

Preventing the Establishment of a Wildlife Disease Reservoir: A Case Study of Bovine Tuberculosis in Wild Deer in Minnesota, USA

Bovine tuberculosis (bTB) has been found in 12 cattle operations and 27 free-ranging white-tailed deer (Odocoileus virginianus) in northwestern Minnesota, following the state's most recent outbreak of the disease in 2005 in the northwest part of the state. Both deer and cattle have the same strain of bTB. The Minnesota Board of Animal Health has been leading efforts to eradicate the disease in Minnesota's cattle, which have included the depopulation of all infected herds, a cattle buy-out program, and mandatory fencing of stored feeds. The Minnesota Department of Natural Resources began surveillance efforts in free-ranging white-tailed deer in fall 2005. All bTB-infected deer have been found within a 16 km2 area in direct association with infected cattle farms. Aggressive efforts to reduce deer densities through liberalized hunting and sharpshooting have resulted in a 55% decline in deer densities. Also, recreational feeding of wild deer has been banned. Disease prevalence in deer has decreased from 1.2% in 2005 to an undetectable level in 2010

Automated sliding susceptibility mapping of rock slopes

International audienceWe present a suite of extensions for ARCVIEW GIS? (ESRI) that allows to map the spatial distribution of first-order mechanical slope-properties in hard rock terrain, e.g. for large slope areas like water reservoir slopes. Besides digital elevation data, this expert-system includes regional continuous grid-based data on geological structures that might act as potential sliding or cutoff planes for rockslides. The system allows rapid automated mapping of geometrical and kinematical slope properties in hard rock, providing the basis for spatially distributed deterministic sliding-susceptibility evaluations on a pixel base. Changing hydrostatic slope conditions and rock mechanical parameters can be implemented and used for simple predictive static stability calculations. Application is demonstrated for a study area in the Harz Mts., Germany

Convergence of simple adaptive Galerkin schemes based on h − h/2 error estimators

We discuss several adaptive mesh-refinement strategies based on (h − h/2)-error estimation. This class of adaptivemethods is particularly popular in practise since it is problem independent and requires virtually no implementational overhead. We prove that, under the saturation assumption, these adaptive algorithms are convergent. Our framework applies not only to finite element methods, but also yields a first convergence proof for adaptive boundary element schemes. For a finite element model problem, we extend the proposed adaptive scheme and prove convergence even if the saturation assumption fails to hold in general

Direct Detection of Products from the Pyrolysis of 2-Phenethyl Phenyl Ether

The pyrolysis of 2-phenethyl phenyl ether (PPE, C_6H_5C_2H_4OC_6H_5) in a hyperthermal nozzle (300-1350 °C) was studied to determine the importance of concerted and homolytic unimolecular decomposition pathways. Short residence times (<100 μs) and low concentrations in this reactor allowed the direct detection of the initial reaction products from thermolysis. Reactants, radicals, and most products were detected with photoionization (10.5 eV) time-of-flight mass spectrometry (PIMS). Detection of phenoxy radical, cyclopentadienyl radical, benzyl radical, and benzene suggest the formation of product by the homolytic scission of the C_6H_5C_2H_4-OC_6H_5 and C_6H_5CH_2-CH_2OC_6H_5 bonds. The detection of phenol and styrene suggests decomposition by a concerted reaction mechanism. Phenyl ethyl ether (PEE, C_6H_5OC_2H_5) pyrolysis was also studied using PIMS and using cryogenic matrix-isolated infrared spectroscopy (matrix-IR). The results for PEE also indicate the presence of both homolytic bond breaking and concerted decomposition reactions. Quantum mechanical calculations using CBS-QB3 were conducted, and the results were used with transition state theory (TST) to estimate the rate constants for the different reaction pathways. The results are consistent with the experimental measurements and suggest that the concerted retro-ene and Maccoll reactions are dominant at low temperatures (below 1000 °C), whereas the contribution of the C_6H_5C_2H_4-OC_6H_5 homolytic bond scission reaction increases at higher temperatures (above 1000 °C)

Beta diversity of plant-pollinator networks and the spatial turnover of pairwise interactions

Interactions between species form complex networks that vary across space and time. Even without spatial or temporal constraints mutualistic pairwise interactions may vary, or rewire, across space but this variability is not well understood. Here, we quantify the beta diversity of species and interactions and test factors influencing the probability of turnover of pairwise interactions across space. We ask: 1) whether beta diversity of plants, pollinators, and interactions follow a similar trend across space, and 2) which interaction properties and site characteristics are related to the probability of turnover of pairwise interactions. Geographical distance was positively correlated with plant and interaction beta diversity. We find that locally frequent interactions are more consistent across space and that local flower abundance is important for the realization of pairwise interactions. While the identity of pairwise interactions is highly variable across space, some speciespairs form interactions that are locally frequent and spatially consistent. Such interactions represent cornerstones of interacting communities and deserve special attention from ecologists and conservation planners alike.Fil: Carstensen, Daniel W.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Sabatino, Cristina Malena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Laboratorio de Ecotono; ArgentinaFil: Trøjelsgaard, Kristian. University Aarhus; Dinamarca. Aalborg University; DinamarcaFil: Morellato, Leonor Patricia C.. Universidade Estadual Paulista Julio de Mesquita Filho; Brasi

Deniz Bilgin batik-resim sergisi

Taha Toros Arşivi, Dosya No: 114-Erol-Hüseyin-Deniz-Çetin-Cevdet Bilgin. Not: Sergi, 17 - 31 Ocak 1986 tarihleri arasında düzenlenmiştir

ifo Konjunkturprognose 2008/2009: Aufschwung geht zu Ende

Die Weltkonjunktur hat im Gefolge der US-Immobilienkrise und der Turbulenzen an den internationalen Finanzmärkten an Dynamik eingebüßt. Das vom ifo Institut erhobene Weltwirtschaftsklima hat sich im zweiten Quartal 2008 massiv verschlechtert; der Indikator fiel auf den niedrigsten Stand seit über sechs Jahren. Der Rückgang resultiert vor allem aus der ungünstigeren Einschätzung der derzeitigen wirtschaftlichen Lage, aber auch die Erwartungen für die nächsten sechs Monate wurden weiter nach unten revidiert. Die Verschlechterung des ifo Weltwirtschaftsklimas betrifft wiederum vor allem Nordamerika und Westeuropa. Der stärkste Rückgang des Klimaindikators ist wie schon in der vorangegangenen Umfrage in den USA zu verzeichnen. Die Expansion der Weltwirtschaft wird sich im Prognosezeitraum spürbar abkühlen. Der Anstieg des Bruttoinlandsprodukts wird sich verlangsamen, da der Höhepunkt des konjunkturellen Zyklus überschritten zu sein scheint. Zudem werden die anhaltende Unsicherheit auf den Finanzmärkten, die negativen Vermögenseffekte sinkender Hauspreise und Aktienkurse, die hohe Inflation sowie die zuletzt stark gestiegenen Ölpreise zunehmend bremsend wirken. Die deutsche Wirtschaft ist überaus schwungvoll in das neue Jahr gestartet. Nach den bisher vorliegenden amtlichen Ergebnissen stieg die gesamtwirtschaftliche Produktion im ersten Quartal 2008 saison- und kalenderbereinigt gegenüber dem Vorquartal um 1,5%. Nach der auch von Sondereffekten begünstigten kräftigen Ausweitung der gesamtwirtschaftlichen Produktion im ersten Quartal 2008 ist für das zweite Quartal mit einem leichten Rückgang des realen Bruttoinlandsprodukts zu rechnen. Im Durchschnitt des ersten Halbjahres 2008 ergibt sich im Vergleich zum zweiten Halbjahr 2007 saison- und kalenderbereinigt ein BIP-Zuwachs von 1,5%; im Vorjahresvergleich beläuft sich die Zunahme auf 2,7%

Epidemiology of the lymphatic-dwelling filarioid nematode Rumenfilaria andersoni in free-ranging moose (Alces alces) and other cervids of North America

Background: Moose (Alces alces) are a culturally and economically valued species in Minnesota, where the northeast population has decreased by 60 % since 2006. The cause of the decline is currently unclear; however, parasites, predation, and climate change have all been implicated. Nematode parasites are important pathogens in North American moose, potentially causing severe disease and mortality. Recent spread of Rumenfilaria andersoni, a filarioid nematode of moose, has been documented in Finnish cervids; however, little is known about the epidemiology of this parasite in North America. Methods: To investigate the prevalence and distribution of R. andersoni, 584 blood samples were collected from live-captured and dead animals and screened microscopically for the presence of microfilariae using a modified Knott's test. Microfilariae were identified based on morphological characteristics. A subset of Knott's-positive animals was subjected to polymerase chain reaction (PCR) with filarioid-specific primers targeting the first internal transcribed spacer region (ITS-1) of the rRNA gene cluster. Results: Rumenfilaria microfilariae were present in 20.5 % of Minnesota moose (n = 352), with slight fluctuations observed over four years. Minnesota white-tailed deer (Odocoileus virginianus) (n = 2) and moose (n = 44) from Alaska, Montana, Washington, Maine, and New Hampshire also harbored R. andersoni, suggesting this parasite occurs widely throughout North American moose herds, and white-tailed deer can serve as a patent host. Sequence analysis of cervid blood (moose, n = 15; white-tailed deer, n = 1) confirmed the identity of R. andersoni and revealed the existence of two distinct clades. Genetic comparisons of R. andersoni isolates from North America and semi-domesticated Finnish reindeer found the two groups to be closely related, supporting previous hypotheses that R. andersoni was recently introduced into Finland by the importation of deer from the United States. Conclusions: To the best of our knowledge these observations represent the first report of R. andersoni within the contiguous United States and reveal this nematode as a common parasite of North American moose and white-tailed deer. Although the implications of R. andersoni infection on moose health is unclear, increased awareness of this parasite will help prevent unintentional introduction of R. andersoni into naive populations via the translocation of wild and captive cervids.Peer reviewe