How present aerosol pollution from North America impacts North Atlantic climate

This paper describes the potential effects of present-day aerosol pollution from North America (USA, Canada) on the climate of the North Atlantic region. The study has been performed by applying the comprehensive atmospheric general circulation model ECHAM5-HAM, which is coupled to a mixed-layer ocean with an embedded thermodynamic sea ice module. The model includes a microphysical aerosol model (HAM), which allows for the assessment of aerosol impacts on climate. Sulphate, black and organic carbon, sea salt and mineral dust are considered as aerosol species. Two equilibrium simulations with two different aerosol pollutant scenarios are compared for each season. We investigate the effect on radiation, temperature, hydrological quantities and dynamics, when human-induced aerosol emissions from North America were omitted. The decrease of both direct and indirect aerosol effects induces a positive change in top of the atmosphere (TOA) radiative fluxes resulting in an overall warming in the whole region. Our results demonstrate the vulnerability especially of the Arctic to the reduction in aerosol load. For fall we find an increase in precipitation over the North Atlantic, associated with a tendency to a larger number of cyclones with high-pressure gradients and a higher frequency in storm days

Das Rundum-Klimapaket

Die Erderwärmung verändert die Welt – ökologisch, ökonomisch und politisch. Klimadienste wollen Entscheidungsträgern helfen, auf den vielfältigen Wandel angemessen zu reagieren. Unsere Autoren waren maßgeblich am Aufbau des Climate Service Center in Hamburg beteiligt. Im Folgenden stellen sie die Arbeit dieser Art von Einrichtungen vor und schildern die Herausforderungen für die Kommunikation

Fluxes of soot black carbon to South Atlantic sediments

Deep sea sediment samples from the South Atlantic Ocean were analyzed for soot black carbon (BC), total organic carbon (TOC), stable carbon isotope ratios (delta C-13), and polycyclic aromatic hydrocarbons (PAHs). Soot BC was present at low concentrations (0.04-0.17% dry weight), but accounted for 3-35% of TOC. Fluxes of soot BC were calculated on the basis of known sedimentation rates and ranged from 0.5 to 7.8 mu g cm(-2) a(-1), with higher fluxes near Africa compared to South America. Values of delta C-13 indicated a marine origin for the organic carbon but terrestrial sources for the soot BC. PAH ratios implied a pyrogenic origin for most samples and possibly a predominance of traffic emissions over wood burning off the African coast. A coupled ocean-atmosphere-aerosol-climate model was used to determine fluxes of BC from 1860 to 2000 to the South Atlantic. Model simulation and measurements both yielded higher soot BC fluxes off the African coast and lower fluxes off the South American coast; however, measured sedimentary soot BC fluxes exceeded simulated values by similar to 1 mu g cm(-2) a(-1) on average (within a factor of 2-4). For the sediments off the African coast, soot BC delivery from the Congo River could possibly explain the higher flux rates, but no elevated soot BC fluxes were detected in the Amazon River basin. In total, fluxes of soot BC to the South Atlantic were similar to 480-700 Gg a(-1) in deep sea sediments. Our results suggest that attempts to construct a global mass balance of BC should include estimates of the atmospheric deposition of BC

A GCM study of future climate response to aerosol pollution reductions

We use the global atmospheric GCM aerosol model ECHAM5-HAM to asses possible impacts of future air pollution mitigation strategies on climate. Air quality control strategies focus on the reduction of aerosol emissions. Here we investigate the extreme case of a maximum feasible end-of-pipe abatement of aerosols in the near term future (2030) in combination with increasing greenhouse gas (GHG) concentrations. The temperature response of increasing GHG concentrations and reduced aerosol emissions leads to a global annual mean equilibrium temperature response of 2.18 K. When aerosols are maximally abated only in the Industry and Powerplant sector, while other sectors stay with currently enforced regulations, the temperature response is 1.89 K. A maximum feasible abatement applied in the Domestic and Transport sector, while other sectors remain with the current legislation, leads to a temperature response of 1.39 K. Increasing GHG concentrations alone lead to a temperature response of 1.20 K. We also simulate 2–5% increases in global mean precipitation among all scenarios considered, and the hydrological sensitivity is found to be significantly higher for aerosols than for GHGs. Our study, thus highlights the huge potential impact of future air pollution mitigation strategies on climate and supports the need for urgent GHG emission reductions. GHG and aerosol forcings are not independent as both affect and are influenced by changes in the hydrological cycle. However, within the given range of changes in aerosol emissions and GHG concentrations considered in this study, the climate response towards increasing GHG concentrations and decreasing aerosols emissions is additive

Clinical Implication of Targeting of Cancer Stem Cells

The existence of cancer stem cells (CSCs) is receiving increasing interest particularly due to its potential ability to enter clinical routine. Rapid advances in the CSC field have provided evidence for the development of more reliable anticancer therapies in the future. CSCs typically only constitute a small fraction of the total tumor burden; however, they harbor self-renewal capacity and appear to be relatively resistant to conventional therapies. Recent therapeutic approaches aim to eliminate or differentiate CSCs or to disrupt the niches in which they reside. Better understanding of the biological characteristics of CSCs as well as improved preclinical and clinical trials targeting CSCs may revolutionize the treatment of many cancers. Copyright (c) 2012 S. Karger AG, Base

A Transplantable Phosphorylation Probe for Direct Assessment of G Protein-Coupled Receptor Activation

The newly developed multireceptor somatostatin analogs pasireotide (SOM230), octreotide and somatoprim (DG3173) have primarily been characterized according to their binding profiles. However, their ability to activate individual somatostatin receptor subtypes (sst) has not been directly assessed so far. Here, we transplanted the carboxyl-terminal phosphorylation motif of the sst2 receptor to other somatostatin receptors and assessed receptor activation using a set of three phosphosite-specific antibodies. Our comparative analysis revealed unexpected efficacy profiles for pasireotide, octreotide and somatoprim. Pasireotide was able to activate sst3 and sst5 receptors but was only a partial agonist at the sst2 receptor. Octreotide exhibited potent agonistic properties at the sst2 receptor but produced very little sst5 receptor activation. Like octreotide, somatoprim was a full agonist at the sst2 receptor. Unlike octreotide, somatoprim was also a potent agonist at the sst5 receptor. Together, we propose the application of a phosphorylation probe for direct assessment of G protein-coupled receptor activation and demonstrate its utility in the pharmacological characterization of novel somatostatin analogs

Sigma Terms of Light-Quark Hadrons

A calculation of the current-quark mass dependence of hadron masses can help in using observational data to place constraints on the variation of nature's fundamental parameters. A hadron's sigma-term is a measure of this dependence. The connection between a hadron's sigma-term and the Feynman-Hellmann theorem is illustrated with an explicit calculation for the pion using a rainbow-ladder truncation of the Dyson-Schwinger equations: in the vicinity of the chiral limit sigma_pi = m_pi/2. This truncation also provides a decent estimate of sigma_rho because the two dominant self-energy corrections to the rho-meson's mass largely cancel in their contribution to sigma_rho. The truncation is less accurate for the omega, however, because there is little to compete with an omega->rho+pi self-energy contribution that magnifies the value of sigma_omega by ~25%. A Poincare' covariant Faddeev equation, which describes baryons as composites of confined-quarks and -nonpointlike-diquarks, is solved to obtain the current-quark mass dependence of the masses of the nucleon and Delta, and thereby sigma_N and sigma_Delta. This "quark-core" piece is augmented by the "pion cloud" contribution, which is positive. The analysis yields sigma_N~60MeV and sigma_Delta~50MeV.Comment: 22 pages, reference list expande

Role of the VEGF ligand to receptor ratio in the progression of mismatch repair-proficient colorectal cancer

The VEGF family of ligands and receptors are intimately involved in tumor angiogenesis, lymphangiogenesis and metastasis. The evaluation of VEGF ligand/receptor ratios may provide a more profound understanding of the involvement of these proteins in colorectal tumour progression. The aim of this study was to elucidate the role of the VEGF ligand/receptor ratios on tumour progression and metastasis in patients with mismatch repair-proficient colorectal cancer

Modern optical astronomy: technology and impact of interferometry

The present `state of the art' and the path to future progress in high spatial resolution imaging interferometry is reviewed. The review begins with a treatment of the fundamentals of stellar optical interferometry, the origin, properties, optical effects of turbulence in the Earth's atmosphere, the passive methods that are applied on a single telescope to overcome atmospheric image degradation such as speckle interferometry, and various other techniques. These topics include differential speckle interferometry, speckle spectroscopy and polarimetry, phase diversity, wavefront shearing interferometry, phase-closure methods, dark speckle imaging, as well as the limitations imposed by the detectors on the performance of speckle imaging. A brief account is given of the technological innovation of adaptive-optics (AO) to compensate such atmospheric effects on the image in real time. A major advancement involves the transition from single-aperture to the dilute-aperture interferometry using multiple telescopes. Therefore, the review deals with recent developments involving ground-based, and space-based optical arrays. Emphasis is placed on the problems specific to delay-lines, beam recombination, polarization, dispersion, fringe-tracking, bootstrapping, coherencing and cophasing, and recovery of the visibility functions. The role of AO in enhancing visibilities is also discussed. The applications of interferometry, such as imaging, astrometry, and nulling are described. The mathematical intricacies of the various `post-detection' image-processing techniques are examined critically. The review concludes with a discussion of the astrophysical importance and the perspectives of interferometry.Comment: 65 pages LaTeX file including 23 figures. Reviews of Modern Physics, 2002, to appear in April issu

Anaphylaxis in Elderly Patients-Data From the European Anaphylaxis Registry

Background: Elicitors and symptoms of anaphylaxis are age dependent. However, little is known about typical features of anaphylaxis in patients aged 65 years or more. Methods: The data from the Network for Online Registration of Anaphylaxis (NORA) considering patients aged ≥65 (elderly) in comparison to data from adults (18–64 years) regarding elicitors, symptoms, comorbidities, and treatment measures were analyzed. Results: We identified 1,123 elderly anaphylactic patients. Insect venoms were the most frequent elicitor in this group (p < 0.001), followed by drugs like analgesics and antibiotics. Food allergens elicited less frequently anaphylaxis (p < 0.001). Skin symptoms occurred less frequently in elderly patients (77%, p < 0.001). The clinical symptoms were more severe in the elderly (51% experiencing grade III/IV reactions), in particular when skin symptoms (p < 0.001) were absent. Most strikingly, a loss of consciousness (33%, p < 0.001) and preexisting cardiovascular comorbidity (59%, p < 0.001) were more prevalent in the elderly. Finally, adrenaline was used in 30% of the elderly (vs. 26% in the comparator group, p < 0.001) and hospitalization was more often required (60 vs. 50%, p < 0.001). Discussion and Conclusion: Anaphylaxis in the elderly is often caused by insect venoms and drugs. These patients suffer more often from cardiovascular symptoms, receive more frequently adrenaline and require more often hospitalization. The data indicate that anaphylaxis in the elderly tends to be more frequently life threatening and patients require intensified medical intervention. The data support the need to recognize anaphylaxis in this patient group, which is prone to be at a higher risk for a fatal outcome