111 research outputs found
Idempotent characters and equivariantly multiplicative splittings of K-theory
We classify the primitive idempotents of the -local complex representation
ring of a finite group in terms of the cyclic subgroups of order prime to
and show that they all come from idempotents of the Burnside ring. Our
results hold without adjoining roots of unity or inverting the order of ,
thus extending classical structure theorems. We then derive explicit
group-theoretic obstructions for tensor induction to be compatible with the
resulting idempotent splitting of the representation ring Mackey functor.
Our main motivation is an application in homotopy theory: we conclude that
the idempotent summands of -equivariant topological -theory and the
corresponding summands of the -equivariant sphere spectrum admit exactly the
same flavors of equivariant commutative ring structures, made precise in terms
of Hill-Hopkins-Ravenel norm maps.
This paper is a sequel to the author's earlier work on multiplicative
induction for the Burnside ring and the sphere spectrum, see arXiv:1802.01938.Comment: 19 pages. Comments welcome! v2: Updated references. Removed a lemma
that is no longer relevant. v3: Changes in response to a referee repor
An assessment of Arctic Ocean freshwater content changes from the 1990s to the 2006-2008 period
Author Posting. © The Author(s), 2010. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Deep Sea Research Part I: Oceanographic Research Papers 58 (2011): 173-185, doi:10.1016/j.dsr.2010.12.002.Unprecedented summer-season sampling of the Arctic Ocean during the period 2006â2008 makes
possible a quasi-synoptic estimate of liquid freshwater (LFW) inventories in the Arctic Ocean basins.
In comparison to observations from 1992â1999, LFW content relative to a salinity of 35 in the layer
from the surface to the 34 isohaline increased by 8400 ± 2000 km3 in the Arctic Ocean (water depth
greater than 500m). This is close to the annual export of freshwater (liquid and solid) from the Arctic
Ocean reported in the literature.
Observations and a model simulation show regional variations in LFW were both due to changes
in the depth of the lower halocline, often forced by regional wind-induced Ekman pumping, and a
mean freshening of the water column above this depth, associated with an increased net sea ice melt
and advection of increased amounts of river water from the Siberian shelves. Over the whole Arctic
Ocean, changes in the observed mean salinity above the 34 isohaline dominated estimated changes in
LFW content; the contribution to LFW change by bounding isohaline depth changes was less than a
quarter of the salinity contribution, and non-linear effects due to both factors were negligible.This work was supported by the Co-Operative Project âThe
North Atlantic as Part of the Earth System: From System Comprehension to Analysis of Regional
Impactsâ funded by the German Federal Ministry for Education and Research (BMBF) and by the European Union Sixth Framework Programme project DAMOCLES (Developing Arctic Modelling and
Observing Capabilities for Long-term Environment Studies), contract number 018509GOCE
Genomes of all known members of a Plasmodium subgenus reveal paths to virulent human malaria
Plasmodium falciparum, the most virulent agent of human malaria, shares a recent common ancestor with the gorilla parasite Plasmodium praefalciparum. Little is known about the other gorilla- and chimpanzee-infecting species in the same (Laverania) subgenus as P. falciparum, but none of them are capable of establishing repeated infection and transmission in humans. To elucidate underlying mechanisms and the evolutionary history of this subgenus, we have generated multiple genomes from all known Laverania species. The completeness of our dataset allows us to conclude that interspecific gene transfers, as well as convergent evolution, were important in the evolution of these species. Striking copy number and structural variations were observed within gene families and one, stevor, shows a host-specific sequence pattern. The complete genome sequence of the closest ancestor of P. falciparum enables us to estimate the timing of the beginning of speciation to be 40,000â60,000 years ago followed by a population bottleneck around 4,000â6,000 years ago. Our data allow us also to search in detail for the features of P. falciparum that made it the only member of the Laverania able to infect and spread in humans
New material of Laophis crotaloides, an enigmatic giant snake from Greece, with an overview of the largest fossil European vipers
Laophis crotaloides was described by Richard Owen as a new and very large fossil viperid snake species from Greece. The type material is apparently lost and the taxon was mostly neglected for more than a century. We here describe a new partial viperid vertebra, collected from the same locality and of equivalent size to the type material. This vertebra indicates that at least one of the three morphological characters that could be used to diagnose L. crotaloides is probably an artifact of the lithographer who prepared the illustration supporting the original description. A revised diagnosis of L. crotaloides is provided on the basis of the new specimen. Despite the fragmentary nature of the new vertebra, it confirms the validity of L. crotaloides, although its exact relationships within Viperidae remain unknown. The new find supports the presence of a large viperid snake in the early Pliocene of northern Greece, adding further data to the diversity of giant vipers from Europe
Privacy-enhanced event scheduling
Event schedulers, well-known from groupware and social software, typically share the problem that they disclose detailed availability patterns of their users. This paper distinguishes event scheduling from electronic voting and proposes a privacy-enhanced event scheduling scheme. Based on superposed sending and DiffieâHellman key agreement, it is designed to be efficient enough for practical implementations while requiring minimal trust in a central entity. Protocols to enable dynamic joining and leaving of participants are given
Hybrid systems, optimal control and hybrid vehicles: theory, methods and applications
This book assembles new methods showing the automotive engineer for the first time how hybrid vehicle configurations can be modeled as systems with discrete and continuous controls. These hybrid systems describe naturally and compactly the networks of embedded systems which use elements such as integrators, hysteresis, state-machines and logical rules to describe the evolution of continuous and discrete dynamics and arise inevitably when modeling hybrid electric vehicles. They can throw light on systems which may otherwise be too complex or recondite. Hybrid Systems, Optimal Control and Hybrid Vehicles shows the reader how to formulate and solve control problems which satisfy multiple objectives which may be arbitrary and complex with contradictory influences on fuel consumption, emissions and drivability. The text introduces industrial engineers, postgraduates and researchers to the theory of hybrid optimal control problems. A series of novel algorithmic developments provides tools for solving engineering problems of growing complexity in the field of hybrid vehicles. Important topics of real relevance rarely found in text books and research publicationsâswitching costs, sensitivity of discrete decisions and there impact on fuel savings, etc.âare discussed and supported with practical applications. These demonstrate the contribution of optimal hybrid control in predictive energy management, advanced powertrain calibration, and the optimization of vehicle configuration with respect to fuel economy, lowest emissions and smoothest drivability. Numerical issues such as computing resources, simplifications and stability are treated to enable readers to assess such complex systems. To help industrial engineers and managers with project decision-making, solutions for many important problems in hybrid vehicle control are provided in terms of requirements, benefits and risks. Advances in Industrial Control aims to report and encourage the transfer of technology in control engineering. The rapid development of control technology has an impact on all areas of the control discipline. The series offers an opportunity for researchers to present an extended exposition of new work in all aspects of industrial control
Effectiveness and equity evaluation of an insurance-wide telephone-counseling program for self-management of chronic diseases: The Health Coach Study
Trajectories of chronic illnesses depend on patient socioeconomic status (SES). This study examines main and equity effects (age, gender, education, region of residence) of a brief telephone self-management intervention on self-rated health and depressive symptoms of health insurance clients with chronic illnesses. Randomized invitation design (nâ=â2628) with predominantly male (82%) older individuals (modal ageâ=â65â74) with one or more chronic illnesses. Primary outcomes: Self-rated health and depressive symptoms. Intervention: Brief CBT-based telephone counseling. Propensity score matching was used to equate intervention and control groups (nâ=â1314 pairs). Change score models were used to analyze changes in health-related outcome measures. The intervention resulted in improvements in self-rated health (dâ=â.37) and fewer depressive symptoms (dâ=â.17) over 4 and 6 months. There were comparable effects across education and regions, but younger and female participants profited more from the intervention compared with older and male participants. A brief telephone-based intervention led to improved self-rated health and well-being in a large sample of participants with chronic health conditions. This effect was observed over and above regular medical care. The intervention was equitable with respect to education and region, but not age and gender
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