594 research outputs found
Adaptation, Mitigation and Risk-Taking in Climate Policy
The future consequences of climate change are highly uncertain. Today, the exact size of possible future damages are widely unknown. Governments try to cope with these risks by investing in mitigation and adaptation measures. Mitigation aims at a reduction of greenhouse gas emissions whereas adaptation reduces the follow-up costs of climate change. In contrast to the existing literature, we explicitly model the decision of risk-averse governments on mitigation and adaptation policies. Furthermore we also consider the interaction of the two strategies. Mitigation efforts of a single country trigger crowding out as other countries will reduce their mitigation efforts. We show that, under fairly mild conditions, a unilateral increase in mitigation efforts of a single country can even increase global emissions. In contrast, a unilateral commitment to large adaptation efforts benefits the single country and may reduce the global risk from climate change at the expense of other countries.climate change, adaptation, mitigation, risk-taking
The effect of soil moisture and atmospheric conditions on the development of shallow cumulus convection: A coupled large-eddy simulation-land surface model study
Many processes and feedback mechanisms are involved in land-atmosphere interactions that play an important role in determining the boundary layer structure throughout the diurnal cycle. Here, the effect of soil moisture on the development of shallow cumulus convection is investigated using a coupled large-eddy simulation (LES)-land surface model (LSM) framework. First, the coupled model is run for an idealised case based on measurements at the ARM Southern Great Plain site on 21 June 1997 to demonstrate that many characteristics of the subcloud layer turbulence and of the cumulus layer can be modelled successfully. Moreover, an extensive sensitivity study is performed with different amounts of soil moisture and varying atmospheric conditions. Our results support the hypothesis that the response of shallow cumulus clouds due to a change of soil moisture severely depends on the thermal stability conditions. Furthermore, they also point out that the atmospheric moisture content is as important as the static stability in determining the boundary layer characteristics and in particular the fractional cloud cover. The results demonstrate that the soil moisture-cloud cover coupling is positive in most of the cases. However, we show that under specific conditions (a less stably stratified moist atmosphere) convective activity and cloud formation is stronger over dry soils, where the principle driving mechanism for cloud development is the boundary layer growth that tends to increase relative humidity by adiabatic cooling of the air at the top of the boundary layer. This leads to a soil moisture cloud cover relationship in which the cloud cover fraction decreases with an increase of soil moisture. Moreover, our findings suggest that in the limiting case of a water saturated soil the mean cloud cover is independent of static stability, but only depends on the vertical integrated atmospheric moisture content
Factors influencing abstinence, anticipation, and delay of sex among adolescent boys in high-STI prevalence communities
Purpose
Abstinence is a core pregnancy and STI prevention strategy. We explore the attitudinal, behavioral, and family contexts relating to abstinence and the decision to delay sex among adolescent boys.
Methods
Adolescent boys ages 14â17 were recruited from community sites using a venue-based sampling method. All eligible boys at venues were invited to participate in an electronic survey. Question items included sexual behaviors, attitudes related to sex, relationships, masculine values, and family contextual items.
Results
We enrolled 667 participants, age 15.7 years, of diverse ethnicity. 252 (38%) were abstinent. Abstinent participants were younger, less likely to report non-coital behaviors, and reported lower conventional masculine values. Among abstinent participants, 62% planned to delay sex, while 38% anticipated sex in the next year. Participants with lower conventional masculine values, and more religious or moral motivations for abstinence were more likely to plan to delay sex.
Discussion
Abstinence among boys is common, even in high STI risk communities. For these boys, abstinence appears to be a complex behavioral decision, influenced by demographic, behavioral, attitudinal and contextual factors such as age, race, non-coital sexual behaviors and masculine values. Understanding the attitudes and contexts of abstinence, including plans to delay sex, can inform the development of public health programs for early fatherhood and STI prevention
Unsichere Klimafolgen und rationale Klimapolitik
FĂŒr die Klimapolitik einzelner LĂ€nder spielt nach Ansicht von Heike Auerswald, Technische UniversitĂ€t Dresden, Kai A. Konrad, Max-Planck-Institut fĂŒr Steuerrecht und Ăffentliche Finanzen, und Marcel Thum, Technische UniversitĂ€t Dresden und Niederlassung Dresden des ifo Instituts, neben der globalen Bedeutung des Problems die groĂe Unsicherheit bezĂŒglich der möglichen zukĂŒnftigen SchĂ€den eine wichtige Rolle. Unilaterale Vorleistungen in der Klimapolitik können in einer Welt risikoaverser Entscheider dazu fĂŒhren, dass die globalen Treibhausgasemissionen steigen. Es empfiehlt sich eine strategische Festlegung auf AnpassungsmaĂnahmen. Diese schĂŒtzen nicht nur das eigene Land vor den Klimafolgen, sondern zwingen auch andere Akteure dazu, mehr in Emissionsvermeidung zu investieren und so die globalen Risiken aus dem Klimawandel zu mindern.Energieversorgung, Nachhaltige Entwicklung, Reform, UmweltvertrĂ€gliche Energiepolitik, Deutschland
Supramolecular organization of the human N-BAR domain in shaping the sarcolemma membrane
This is the final version of the article. Available from Elsevier via the DOI in this record.The 30 kDa N-BAR domain of the human Bin1 protein is essential for the generation of skeletal muscle T-tubules. By electron cryo-microscopy and electron cryo-tomography with a direct electron detector, we found that Bin1-N-BAR domains assemble into scaffolds of low long-range order that form flexible membrane tubules. The diameter of the tubules closely matches the curved shape of the N-BAR domain, which depends on the composition of the target membrane. These insights are fundamental to our understanding of T-tubule formation and function in human skeletal muscle.This work was supported by grants from the Deutsche Forschungsgemeinschaft (GRK 1026, SFB610) (A.A., T.G., J.B.), the BMBF ZIK program (A.M., J.B.), the European Regional Development Fund of the European Commission (A.M., T.G.: EFRE 1241 12 0001), and the state Sachsen-Anhalt (A.M., T.G., J.B.)
Impact of the School Environment on Retention in Care Among HIV-Positive Youth in Kisumu, Kenya
Comment on "Rainfall erosivity in Europe" by Panagos et al. (Sci. Total Environ., 511, 801â814, 2015)
Recently a rainfall erosivity map has been published. We show that the values of this map contain considerable bias because (i) the temporal resolution of the rain data was insufficient, which likely underestimates rain erosivity by about 20%, (ii) no attempt had been included to account for the different time periods that were used for different countries, which can modify rain erosivity by more than 50%, (iii) and likely precipitation data had been used instead of rain data and thus rain erosivity is overestimated in areas with significant snowfall. Furthermore, the seasonal distribution of rain erosivity is not provided, which does not allow using the erosivity map for erosion prediction in many cases. Although a rain erosivity map for Europe would be highly desirable, we recommend using the national erosivity maps until these problems have been solved. Such maps are available for many European countries. (C) 2015 Elsevier B.V. All rights reserved
Temporary inhibition of papain by hairpin loop mutants of chicken cystatin Distorted binding of the loops results in cleavage of the Gly9-Ala10 bond
AbstractTemporary inhibition of the cysteine proteinases papain and cathepsin L was observed with several hairpin loop mutants of recombinant chicken cystatin at enzyme concentrations above nanomolar. Kinetic modelling of inhibition data, gel electrophoresis and amino acid sequencing revealed that reappearance of papain activity is due to selective cleavage of the Gly9-Ala10 bond in the N-terminal binding area of the chicken cystatin variants, resulting in truncated inhibitors of lower affinity. Cleavage of the same bond by contaminating papaya proteinase IV was ruled out by previous purification of papain and suitable control experiments. According to the proposed kinetic model, cleavage occurs within the enzyme-inhibitor complex with first order rate constants ktemp of 2.3 Ă 10â3 up to 5 Ă 10â1 sâ1. A similar ktempKm ratio was found for all mutants (0.7 Ă 106â2.1 Ă 106 sâ1·Mâ1); it is almost identical with the kcatKm ratio of the peptide substrate Z-Phe-Arg-NHMec. These results suggest that distorted contacts of one of the hairpin loops affect binding of the N-terminal contact area in a way that covalent interaction of the Gly9-Ala10 bond with the active-site Cys residue of papain can occur and the bond is cleaved in a substrate-like manner
A temperatureâcontrolled, circular maintenance system for studying growth and development of pelagic tunicates (salps)
Salps have attracted attention as zooplankton organisms that may be able to expand their habitat range and increase their ecological importance in the face of ongoing global warming. Due to their gelatinous nature, unique feeding strategy, and reproductive ecology such changes could have profound impacts on regional marine ecosystems. While their role in the regional carbon cycle is receiving attention, our knowledge of their physiology and life cycle is still limited. This knowledge gap is mainly due to their fragile gelatinous nature, which makes it difficult to capture and maintain intact specimen in the laboratory. We present here a modified kreisel tank system that has been tested onboard a research vessel with the Southern Ocean salp Salpa thompsoni and at a research station with Salpa fusiformis and Thalia democratica from the Mediterranean Sea. Successful maintenance over days to weeks allowed us to obtain relative growth and developmental rates comparable to in situ field samples of S. thompsoni and S. fusiformis, and provided insights into previously unknown features of their life cycle (e.g., testes development). Our results show that traditional methods of estimating growth, such as cohort analysis, may lead to a general overestimation of growth rates and neglect individual strategies (e.g., shrinkage), which can affect the results and conclusions drawn from population dynamic models. By providing a starting point for the successful maintenance of different species, comparable experiments on the physiology of salps is made possible. This will contribute to refining model parameters and improving the reliability of the predictions
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