771 research outputs found
Non-invariant two-loop counterterms for the three-gauge-boson vertices
Some practical applications of algebraic renormalization are discussed. In
particular we consider the two-loop QCD corrections to the three-gauge-boson
vertices involving photons, Z and W bosons. For this purpose also the
corresponding two-point functions have to be discussed. A recently developed
procedure is used to analyze the breaking terms of the functional identities
and explicit formulae for the universal counterterms are provided. Special
attention is devoted to the treatment of infra-red divergences.Comment: Some minor corrections and improved discussion in the one-loop
sectio
Impact Forecasting to Support Emergency Management of Natural Hazards
Forecasting and early warning systems are important investments to protect lives, properties, and livelihood. While early warning systems are frequently used to predict the magnitude, location, and timing of potentially damaging events, these systems rarely provide impact estimates, such as the expected amount and distribution of physical damage, human consequences, disruption of services, or financial loss. Complementing early warning systems with impact forecasts has a twofold advantage: It would provide decision makers with richer information to take informed decisions about emergency measures and focus the attention of different disciplines on a common target. This would allow capitalizing on synergies between different disciplines and boosting the development of multihazard early warning systems. This review discusses the state of the art in impact forecasting for a wide range of natural hazards. We outline the added value of impact-based warnings compared to hazard forecasting for the emergency phase, indicate challenges and pitfalls, and synthesize the review results across hazard types most relevant for Europe
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Trace analysis of osmium and rhenium by resonance ionization mass spectrometry of sputtered atoms
The quantitative trace analysis of Os and Re was investigated using the surface analysis by resonance ionization of sputtered atoms (SARISA) apparatus developed at Argonne National Laboratory. SARISA samples the large fraction of sputtered neutral atoms and utilizes multiphoton resonance ionization to suppress atomic and molecular interferences. Matrix effects are considerably reduced for high ionization occurs in the gas phase and is independent of the physical properties of the substrate. Synthetic metal standards and iron meteorites of known bulk Os concentration were used to establish a calibration curve for Os to test the linearity of the Os{sup +} signal over a large range in concentration. 7 refs., 1 fig
Role of carbon cycle observations and knowledge in carbon management
Author Posting. © Annual Reviews, 2003. This article is posted here by permission of Annual Reviews for personal use, not for redistribution. The definitive version was published in Annual Review of Environment and Resources 28 (2003): 521-558, doi:10.1146/annurev.energy.28.011503.163443.Agriculture and industrial development have led to inadvertent changes
in the natural carbon cycle. As a consequence, concentrations of carbon dioxide and other greenhouse gases have increased in the atmosphere and may lead to changes in
climate. The current challenge facing society is to develop options for future management
of the carbon cycle. A variety of approaches has been suggested: direct reduction
of emissions, deliberate manipulation of the natural carbon cycle to enhance sequestration,
and capture and isolation of carbon from fossil fuel use. Policy development to
date has laid out some of the general principles to which carbon management should
adhere. These are summarized as: how much carbon is stored, by what means, and
for how long. To successfully manage carbon for climate purposes requires increased
understanding of carbon cycle dynamics and improvement in the scientific capabilities
available for measurement as well as for policy needs. The specific needs for scientific
information to underpin carbon cycle management decisions are not yet broadly
known. A stronger dialogue between decision makers and scientists must be developed
to foster improved application of scientific knowledge to decisions. This review focuses
on the current knowledge of the carbon cycle, carbon measurement capabilities
(with an emphasis on the continental scale) and the relevance of carbon cycle science
to carbon sequestration goals.The National Center for Atmospheric Research is supported by the National Science
Foundation
Genetic variability of Phytophthora sojae isolates from Argentina
Phytophthora sojae causes root and stem rot, one of the most important diseases of soybean worldwide. Genetic diversity of 32 Phytophthora sojae isolates of different geographic origin from Argentina was evaluated with RAPD markers. The isolates were collected from diseased soybean plants and soil samples from Santa Fe, Buenos Aires, Córdoba and Entre Ríos provinces, in the Pampeana Region. DNA was amplified with 20 decanucleotides primers. Seven primers amplified 49 fragments, of which 35 were polymorphic, indicating high variability. RAPD analysis detected intraspecific variability even among isolates of the same geographic origin. © 2007 by The Mycological Society of America.Fil:Gally, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Ramos, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Dokmetzian, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Lopez, S.E. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Molecular characterization of Colletotrichum species causing soybean anthracnose in Argentina
Twenty-six isolates obtained from soybean crops (Glycine max) with typical anthracnose symptoms were identified as Colletotrichum truncatum (73 %) and C. destructivum (26 %). Their genetic relationships were studied using the AFLP method. A UPGMA phenogram divided the strains into two clusters corresponding with the two species. Genetic distances based on association coefficient were 0.71-0.89 among the 18 C. truncatum strains and 0.67-1 among the eight C. destructivum strains. Genetic variability within species, measured in terms of percentage of polymorphic loci, was high (<90%). Only two isolates showed 100% similarity, suggesting high intraspecific variability. © 2013. Mycotaxon, Ltd.Fil:Ramos, A.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Cinto, I. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Gally, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
Dopaminergic regulation of ion transport in gills of the euryhaline semiterrestrial crab Chasmagnathus granulatus: Interaction between D1- and D2-like receptors
The effects of dopamine (DA) and dopaminergic agonists and antagonists on ion transport were studied in isolated perfused gills of the crab Chasmagnathus granulatus. DA applied under steady state conditions (perfusion with hemolymph-like saline) produced a transient increase of the transepithelial potential difference (V tc) from 2.2±0.2 to 4.8±0.3 mV, describing an initial cAMP-dependent stimulating phase followed by an inhibitory phase. Spiperone and domperidone (antagonists of D2-like DA receptors in vertebrates) completely blocked the response to DA, while the D1-like antagonist SCH23390 blocked only the inhibitory phase. Theophylline (phosphodiesterase inhibitor) and okadaic acid (protein phosphatases PP1 and PP2A inhibitor) were also able to block the inhibitory phase, suggesting that it depends on adenylyl cyclase inhibition and on protein phosphatases. When the gills were perfused with hypoosmotic solution, or with the adenylyl cyclase activator forskolin, V te was increased several-fold. DA applied under these stimulated conditions partially reversed the Vte increase by 54% and 25%, respectively. Similarly, the D1-like agonist, fenoldopam, produced a 33% reduction in the stimulated V te. We propose that, in C. granulatus gills, DA stimulates adenylyl cyclase and therefore ion transport through D1-like receptors linked to a Gs protein, although they respond to antagonists that interact with D2-like receptors in vertebrates. The inhibitory phase seems to be mediated by D2-like receptors linked to a Gi/o protein, which inhibits adenylyl cyclase, although these receptors can be activated or blocked by agonists or antagonists that interact with D1-like receptors in vertebrates and insects.Fil:Genovese, G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Ortiz, N. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Regueira, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Tresguerres, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Luquet, C.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina
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