356 research outputs found
On the 2d Zakharov system with L^2 Schr\"odinger data
We prove local in time well-posedness for the Zakharov system in two space
dimensions with large initial data in L^2 x H^{-1/2} x H^{-3/2}. This is the
space of optimal regularity in the sense that the data-to-solution map fails to
be smooth at the origin for any rougher pair of spaces in the L^2-based Sobolev
scale. Moreover, it is a natural space for the Cauchy problem in view of the
subsonic limit equation, namely the focusing cubic nonlinear Schroedinger
equation. The existence time we obtain depends only upon the corresponding
norms of the initial data - a result which is false for the cubic nonlinear
Schroedinger equation in dimension two - and it is optimal because
Glangetas-Merle's solutions blow up at that time.Comment: 30 pages, 2 figures. Minor revision. Title has been change
Present and projected future mean radiant temperature for three European cities
Present-day and projected future changes in mean radiant temperature, T mrt in one northern, one mid-, and one southern European city (represented by Gothenburg, Frankfurt, and Porto), are presented, and the concept of hot spots is adopted. Air temperature, T a , increased in all cities by 2100, but changes in solar radiation due to changes in cloudiness counterbalanced or exacerbated the effects on T mrt. The number of days with high T mrt in Gothenburg was relatively unchanged at the end of the century (+1 day), whereas it more than doubled in Frankfurt and tripled in Porto. The use of street trees to reduce daytime radiant heat load was analyzed using hot spots to identify where trees could be most beneficial. Hot spots, although varying in intensity and frequency, were generally confined to near sunlit southeast-southwest facing walls, in northeast corner of courtyards, and in open spaces in all three cities. By adding trees in these spaces, the radiant heat load can be reduced, especially in spaces with no or few trees. A set of design principles for reducing the radiant heat load is outlined based on these findings and existing literature
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Whey protein lowers systolic blood pressure and Ca-caseinate reduces serum TAG after a high-fat meal in mildly hypertensive adults
Epidemiological studies show an inverse association between dairy consumption and blood pressure (BP) but there are few data on the postprandial effects of milk proteins. This study examined their
effects, compared to maltodextrin, on postprandial BP and other CVD risk markers in volunteers with mild and pre-hypertension over an 8 h period. In this double-blinded, randomised, cross-over, controlled study 27 adults ingested a high-fat, isoenergetic breakfast and lunch with 28 g whey
protein, 28 g Ca-caseinate or 27 g maltodextrin. Whey protein reduced systolic BP compared with Ca-caseinate (â15.2 ± 13.6 mmHg) and maltodextrin (â23.4 ± 10.5 mmHg) up to 5 h post-ingestion. There was an improvement in arterial stiffness after whey protein compared with maltodextrin (incremental Area Under the Curve- iAUC0â8h: +14.4 ± 6.2%). Despite similar glucose levels after both whey protein and Ca-caseinate, whey protein induced a higher insulin response than Cacaseinate (iAUC0â8h: +219.5 ± 54.6 pmol/L). Ca-caseinate induced less suppression of non-esterified fatty acids than whey protein (iAUC0â5h: â58.9 ± 135.5 ÎŒmol/L) and maltodextrin (iAUC0â5h: â106.9 ± 89.4 ÎŒmol/L) and induced a smaller postprandial triacylglycerol response than whey protein (iAUC0â8h: â1.68 ± 0.6 mmol/L). Milk proteins co-ingestion with high-fat meals may have the potential to maintain or improve CVD risk factors
Nonlinear coherent states and Ehrenfest time for Schrodinger equation
We consider the propagation of wave packets for the nonlinear Schrodinger
equation, in the semi-classical limit. We establish the existence of a critical
size for the initial data, in terms of the Planck constant: if the initial data
are too small, the nonlinearity is negligible up to the Ehrenfest time. If the
initial data have the critical size, then at leading order the wave function
propagates like a coherent state whose envelope is given by a nonlinear
equation, up to a time of the same order as the Ehrenfest time. We also prove a
nonlinear superposition principle for these nonlinear wave packets.Comment: 27 page
Caracterização da cinza de cama sobreposta de suĂnos e seu aproveitamento em compĂłsitos cimentĂcios
The deep bedding is a swine alternative production, especially in the finishing phase, whose byproduct can be recycled, reducing the environmental impact. The objectives of this study were to characterize the ash coming from the controlled burning of the swine deep bedding (SDBA) based on rice husk, and to evaluate their performance in composites as a partial substitute for Portland cement (PC). To measure the differences between SDBA and rice husk ash (RHA) as a reference, we have characterized: particle size distribution, real specific density, x-ray diffraction, electrical conductivity, scanning electron microscopy, chemical analysis and loss on ignition. Samples were prepared for two experimental series: control, and another one with the partial replacement of 30% of SDBA in relation to the mass of the Portland cement. According to the results obtained for physical and mechanical characterization, the composites with SDBA can be used as a constructive element in the rural construction
Students for global oncology: Building a movement for student education and engagement in an emerging field
Program/Project Purpose: Increased recognition of the global cancer burden and inequalities in care and outcomes have led to the growing field of global oncology, focused on strengthening health systems to improve cancer prevention and care. Motivated students and trainees are in need of pathways to approach these challenges. In 2012, Harvard Medical students formed Students for Global Oncology (S4GO), an adjunct to the larger inter-professional organization Global Oncology. The group had three aims: 1) connect students with mentors in the field, 2) develop novel approaches in global oncology, and 3) disseminate global oncology knowledge. Structure/Method/Design: S4GO has created content and organized events to increase awareness about the global cancer burden, while promoting trainee opportunities in research and practical hands-on projects. Engagement was enhanced by mentorship from more senior students and faculty, to interface with existing global oncology projects. Outcomes & Evaluation: Since 2012, S4GO has grown from two to 68 students. Currently, new chapters at seven other institutions in the US and Canada are being developed. As of October 2014, S4GO has developed a case-based cancer care delivery curriculum with six case-based seminars, along with numerous blog entries and interviews of leading researchers in the field of global oncology, all available on the S4GO website. Students have completed projects in over nine countries and are actively involved in technological and on-the-ground efforts to develop creative solutions and collaborations aimed at easing the global cancer burden. Held in February 2014, the inaugural student-led global oncology symposium involved 200 individuals from across the world, including leaders in global health, pharmaceutical industry, public policy and cancer care. This symposium has been viewed by hundreds online and has fostered novel collaborations and projects focused on enhancing cancer care delivery. Going Forward: In the coming years, S4GO will continue efforts to build awareness and catalyze creative solutions for cancer care in resource-limited settings. These efforts will increase exposure for novel and successful student efforts as well as intra-institutional and intra-professional activity
On the Inverse Scattering Method for Integrable PDEs on a Star Graph
© 2015, Springer-Verlag Berlin Heidelberg. We present a framework to solve the open problem of formulating the inverse scattering method (ISM) for an integrable PDE on a star-graph. The idea is to map the problem on the graph to a matrix initial-boundary value (IBV) problem and then to extend the unified method of Fokas to such a matrix IBV problem. The nonlinear Schrödinger equation is chosen to illustrate the method. The framework unifies all previously known examples which are recovered as particular cases. The case of general Robin conditions at the vertex is discussed: the notion of linearizable initial-boundary conditions is introduced. For such conditions, the method is shown to be as efficient as the ISM on the full-line
Sediment properties as important predictors of carbon storage in zostera marina meadows: a comparison of four European areas
Seagrass ecosystems are important natural carbon sinks but their efficiency varies greatly depending on species composition and environmental conditions. What causes this variation is not fully known and could have important implications for management and protection of the seagrass habitat to continue to act as a natural carbon sink. Here, we assessed sedimentary organic carbon in Zostera marina meadows (and adjacent unvegetated sediment) in four distinct areas of Europe (Gullmar Fjord on the Swedish Skagerrak coast, Asko in the Baltic Sea, Sozopol in the Black Sea and Ria Formosa in southern Portugal) down to similar to 35 cm depth. We also tested how sedimentary organic carbon in Z. marina meadows relates to different sediment characteristics, a range of seagrass-associated variables and water depth. The seagrass carbon storage varied greatly among areas, with an average organic carbon content ranging from 2.79 +/- 0.50% in the Gullmar Fjord to 0.17 +/- 0.02% in the area of Sozopol. We found that a high proportion of fine grain size, high porosity and low density of the sediment is strongly related to high carbon content in Z. marina sediment. We suggest that sediment properties should be included as an important factor when evaluating high priority areas in management of Z. marina generated carbon sinks
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