Bounding Global Aerosol Radiative Forcing of Climate Change.

Aerosols interact with radiation and clouds. Substantial progress made over the past 40 years in observing, understanding, and modeling these processes helped quantify the imbalance in the Earth's radiation budget caused by anthropogenic aerosols, called aerosol radiative forcing, but uncertainties remain large. This review provides a new range of aerosol radiative forcing over the industrial era based on multiple, traceable, and arguable lines of evidence, including modeling approaches, theoretical considerations, and observations. Improved understanding of aerosol absorption and the causes of trends in surface radiative fluxes constrain the forcing from aerosol-radiation interactions. A robust theoretical foundation and convincing evidence constrain the forcing caused by aerosol-driven increases in liquid cloud droplet number concentration. However, the influence of anthropogenic aerosols on cloud liquid water content and cloud fraction is less clear, and the influence on mixed-phase and ice clouds remains poorly constrained. Observed changes in surface temperature and radiative fluxes provide additional constraints. These multiple lines of evidence lead to a 68% confidence interval for the total aerosol effective radiative forcing of -1.6 to -0.6 W m-2, or -2.0 to -0.4 W m-2 with a 90% likelihood. Those intervals are of similar width to the last Intergovernmental Panel on Climate Change assessment but shifted toward more negative values. The uncertainty will narrow in the future by continuing to critically combine multiple lines of evidence, especially those addressing industrial-era changes in aerosol sources and aerosol effects on liquid cloud amount and on ice clouds.

Farmers' valuation of incentives to produce genetically modified organism-free milk: Insights from a discrete choice experiment in Germany.

This paper investigates farmers' willingness to participate in a genetically modified organism (GMO)-free milk production scheme offered by some German dairy companies. The empirical analysis is based upon discrete choice experiments with 151 dairy farmers from 2 regions in Germany. A conditional logit estimation reveals a strong positive effect of the price premium on offer. Reliable feed monitoring and free technical support increase the likelihood of scheme adoption, the latter however only in farms that have been receiving technical support in other fields. By contrast, any interference with the entrepreneurial autonomy of farmers, through pre-arranged feed procurement or prescriptive advice on the part of the dairy company, lowers acceptance probabilities. Farmers' attitudes toward cultivation of genetically modified soy, their assessment of the market potential of GMO-free milk and future feed prices were found to be significant determinants of adoption, as are farmer age, educational status, and current feeding regimens. Respondents requested on average a mark-up of 0.80 eurocents per kilogram of milk to accept a contract. Comparison of the estimates for the 2 regions suggests that farmers in northern Germany are, on average, more likely to convert to genetically modified-free production; however, farmers in the south are, ceteris paribus, more responsive to an increase in the price premium offered. A latent class model reveals significant differences in the valuation of scheme attributes between 2 latent classes of adopters and nonadopters.

The Global Atmosphere-aerosol Model ICON-A-HAM2.3-Initial Model Evaluation and Effects of Radiation Balance Tuning on Aerosol Optical Thickness.

The Hamburg Aerosol Module version 2.3 (HAM2.3) from the ECHAM6.3-HAM2.3 global atmosphere-aerosol model is coupled to the recently developed icosahedral nonhydrostatic ICON-A (icon-aes-1.3.00) global atmosphere model to yield the new ICON-A-HAM2.3 atmosphere-aerosol model. The ICON-A and ECHAM6.3 host models use different dynamical cores, parameterizations of vertical mixing due to sub-grid scale turbulence, and parameter settings for radiation balance tuning. Here, we study the role of the different host models for simulated aerosol optical thickness (AOT) and evaluate impacts of using HAM2.3 and the ECHAM6-HAM2.3 two-moment cloud microphysics scheme on several meteorological variables. Sensitivity runs show that a positive AOT bias over the subtropical oceans is remedied in ICON-A-HAM2.3 because of a different default setting of a parameter in the moist convection parameterization of the host models. The global mean AOT is biased low compared to MODIS satellite instrument retrievals in ICON-A-HAM2.3 and ECHAM6.3-HAM2.3, but the bias is larger in ICON-A-HAM2.3 because negative AOT biases over the Amazon, the African rain forest, and the northern Indian Ocean are no longer compensated by high biases over the sub-tropical oceans. ICON-A-HAM2.3 shows a moderate improvement with respect to AOT observations at AERONET sites. A multivariable bias score combining biases of several meteorological variables into a single number is larger in ICON-A-HAM2.3 compared to standard ICON-A and standard ECHAM6.3. In the tropics, this multivariable bias is of similar magnitude in ICON-A-HAM2.3 and in ECHAM6.3-HAM2.3. In the extra-tropics, a smaller multivariable bias is found for ICON-A-HAM2.3 than for ECHAM6.3-HAM2.3.

[The dorsal spondylodesis of rotationally unstable thoracic fractures. Is additional ventral stabilization necessary?]. / Dorsale Spondylodese rotationsinstabiler Frakturen der Brustwirbelsäule. Bedarf sie einer ventralen Gegenstabilisierung?

METHODS: A total of 60 patients with solely dorsally reconstructed type C fractures of the thoracic spine admitted between January 2000 and December 2003 were retrospectively evaluated. Stability was determined by measuring kyphosis of the vertebral body, the operated segments and of lateral bending on the basis of plain films and computed tomography immediately postoperatively and after 2 and 19 months. RESULTS: There were 48% C2, 38% C1 and 13% C3 fractures. Of the injuries, 28% were caused by motorbike accidents, 25% by car accidents, 23% by falling from a height, 13% by suicidal jumps, 3% by ski accidents and 3% for other reasons. A total of 92% of the patients had severe thoracic trauma as attendant injuries, 42% further vertebral fractures, 35% a head injury, 30% an extremity fracture, 15% a clavicle fracture, 8% an abdominal trauma and 7% a fractured pelvis. At 19+/-12 months postoperatively, the angle of the operated segments increased by 4.7 degrees +/-4.0 degrees and that of lateral bending of the operated segments by 0.7 degrees +/-1.8 degrees compared to the immediate postoperative values. CONCLUSION: In spite of the high instability of the injured spine, the collective examined had no relevant postoperative loss of correction and no increase in lateral bending. Therefore, a solely dorsal reconstruction is sufficient, reasonable and economical.

Effector--target cell interaction of lymph node cells from galactocerebroside-sensitized rats with oligodendrocytes of brain cell cultures.

Inbred Lewis rats were sensitized with galactocerebrosides (GC) and hemocyanin. After 10 years lymph node cells (LNC) depleted of phagocytic cells were obtained. These cells were tested on mixed brain cell cultures enriched with GC-positive oligodendrocytes. Within 3--48 h of incubation, conjugate formation between LNC and oligodendrocytes was observed. Interaction of effector cells with their target resulted in defective oligodendrocytes. Anti-GC-LNC did not adhere to or lyse astrocytes or fibroblasts. Control LNC from rats sensitized only with the carrier protein did not interact with oligodendrocytes.

[The spontaneous spinal epidural haematoma]. / Das spontane spinale epidurale Hämatom.

Spontaneous spinal epidural haematoma (SSEH) is a rare and serious condition. Four cases of SSEH are presented in this paper, three of which were in the cervical segment while one involved the entire spine. In two of these four cases the diagnosis was not made until late in the course, and persisting neurological deficits resulted; one case was diagnosed early and the neurological outcome was good; and in one the decompression achieved was inadequate, owing to intraoperative complications. Laminectomy was performed in all four cases for the purpose of decompression of the spinal cord but at different intervals after the onset of symptoms and with different neurological outcomes. The prognosis of SSEH depends heavily on the time that elapses between the onset of symptoms and the surgical treatment. The diagnostic procedure of choice is MRI.

Solid ammonium sulfate aerosols as ice nuclei: a pathway for cirrus cloud formation.

Laboratory measurements support a cirrus cloud formation pathway involving heterogeneous ice nucleation by solid ammonium sulfate aerosols. Ice formation occurs at low ice-saturation ratios consistent with the formation of continental cirrus and an interhemispheric asymmetry observed for cloud onset. In a climate model, this mechanism provides a widespread source of ice nuclei and leads to fewer but larger ice crystals as compared with a homogeneous freezing scenario. This reduces both the cloud albedo and the longwave heating by cirrus. With the global ammonia budget dominated by agricultural practices, this pathway might further couple anthropogenic activity to the climate system.

Halogenated methyl-phenyl ethers (anisoles) in the environment: determination of vapor pressures, aqueous solubilities, Henry's law constants, and gas/water- (Kgw), n-octanol/water- (Kow) and gas/n-octanol (Kgo) partition coefficients.

Halogenated methyl-phenyl ethers (methoxybenzenes, anisoles) are ubiquitous organics in the environment although they are not produced in industrial quantities. Modelling the fate of organic pollutants such as halogenated anisoles requires a knowledge of the fundamental physico-chemical properties of these compounds. The isomer-specific separation and detection of 60 of the 134 possible congeners allowing an environmental fingerprinting are reported in this study. The vapor pressure p0(L) of more than 60 and further physico-chemical properties of 26 available congeners are given. Vapor pressures p0(L), water solubilities S(L)W, and n-octanol/water partition coefficients Kow were determined by capillary HR-GC (High Resolution Gas Chromatography) on a non-polar phase and by RP-HPLC (Reversed Phase High Performance Liquid Chromatography) on a C18 phase with chlorobenzenes as reference standards. From these experimental data the Henry's law constants H, and the gas/water Kgw and gas/n-octanol Kgo partition coefficients were calculated. We found that vapor pressures, water solubilities, and n-octanol/water partition coefficients of the halogenated anisoles are close to those of the chlorobenzenes. A similar environmental fate of both groups can, therefore, be predicted.

Interaction of high density lipoproteins with cholesteryl ester-laden macrophages: biochemical and morphological characterization of cell surface receptor binding, endocytosis and resecretion of high density lipoproteins by macrophages.

Morphological and biochemical experiments were carried out to investigate the interaction of human serum high density lipoproteins (HDL) with mouse peritoneal macrophages. It is demonstrated that resident mouse peritoneal macrophages express HDL receptors. Subsequent to receptor-mediated binding, HDL are internalized and intracellularly transported into endosomes. These endosomes do not fuse with the lysosomal compartment but interact with the margin of intracellular plasma lipid droplets. Macrophages do not degrade, but rather resecrete internalized HDL particles as described for the transferrin-receptor pathway. HDL binding to freshly isolated macrophages is saturable at a concentration of approximately 320 ng HDL-protein/mg cell protein and a Scatchard plot indicates the presence of some 130 000-190 000 receptors/cell with a Kd of approximately 9 X 10(-7) M. Binding of HDL on the macrophage surface is significantly enhanced in cholesterol-laden macrophages, whereas the increase in the rate of uptake and secretion is less pronounced. Within the HDL fraction the HDL2 subclass showed higher binding, uptake and secretion activity as compared with HDL3. From these experimental data we postulate that cholesterol uptake from macrophages is mediated by HDL particles which interact with these cells via a receptor-mediated retroendocytosis pathway.

[Prevention of thromboembolism in spinal fractures with spinal cord injuries. Standard heparin versus low-molecular-weight heparin in acute paraplegia]. / Thromboembolieprophylaxe bei Wirbelsäulenfrakturen mit Rückenmarkverletzungen. Standard-Heparin versus niedermolekulares Heparin bei frischen Querschnittsyndromen.

In a prospective, randomized, open study, the therapeutic efficacy of a long-term prophylaxis with standard heparin (SH) was compared with that of low-molecular-weight heparin (LMWH) Dalteparin in 166 patients who had spinal fractures with spinal cord injury. 86 patients were treated with SH 2 x 7500 U s.c. and 80 patients were treated with LMWH 1 x 5000 anti-Xa U s.c. once daily. The screening was implemented by daily bedside-examination. In case of clinical thromboembolism-symptoms patients had confirmatory venography or lung scans. In the SH-group 12 (14.0%) patients had deep vein thrombosis and in the LMWH-group 6 (7.5%). Pulmonary embolism was detected two times in the SH-group (2.33%) and only one time in the LMWH-group (1.25%). A significant difference could not be shown, but is descriptive evident.

[Reconstruction of an extensive anterior tracheal defect in a tetraplegic patient during long-term ventilation by autologous cartilage clasps within a pectoralis major flap]. / Rekonstruktion eines ausgedehnten Trachealvorderwanddefekts bei beatmungspflichtiger Tetraplegie durch Pectoralis-major-Lappen und autologe Knorpelspäne.

Tetraplegic patients on permanent respirator therapy are likely to develop cuff related pressure ulceration of the trachea with subsequent tracheomalacia in the cuff level. Regional flaps for the reconstruction of anterior defects are insufficient due to the lack of rigidity and resulting intolerance of the cuff-pressure. Tracheal prostheses are not suitable in the inflammatory tissue in patients requiring continuous respirator therapy. A case report on a permanent reconstruction of an extensive anterior defect of the trachea employing a pedicled pectoralis--major flap incorporating autologous cartilage is presented. Due to "upside-down" rotation of the flap with the cartilage clasps implanted subcutaneously, an epithelialized reconstruction of the anterior tracheal wall was achieved in a length of 10 cm. Sufficient stability of this reconstruction is now given for 42 months.