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Combining atmospheric Δ14CO2 data sets from different networks or laboratories requires secure knowledge on their compatibility. In the present study, we compare Δ14CO2 results from the Heidelberg low-level counting (LLC) laboratory to 12 international accelerator mass spectrometry (AMS) laboratories using distributed aliquots of five pure CO2 samples. The averaged result of the LLC laboratory has a measurement bias of –0.3±0.5‰ with respect to the consensus value of the AMS laboratories for the investigated atmospheric Δ14C range of 9.6 to 40.4‰. Thus, the LLC measurements on average are not significantly different from the AMS laboratories, and the most likely measurement bias is smaller than the World Meteorological Organization (WMO) interlaboratory compatibility goal for Δ14CO2 of 0.5‰. The number of intercomparison samples was, however, too small to determine whether the measurement biases of the individual AMS laboratories fulfilled the WMO goal.
Vitamin D has an important role in calcium homeostasis and is known to have various health-promoting effects. Moreover, potential interactions between vitamin D and physical activity have been suggested. This study aims to investigate the relationship between 25-hydroxyvitamin D (25(OH)D) and exercise capacity quantified by cardiopulmonary exercise testing (CPET). For this, 1377 participants from the Study of Health in Pomerania (SHIP-1) and 750 participants from the independent SHIP-TREND cohort were investigated. Standardised incremental exercise tests on a cycle ergometer were performed to assess exercise capacity by VO2 at anaerobic threshold, peakVO2, O2 pulse and peak power output. Serum 25(OH)D levels were measured by an automated chemiluminescence immunoassay. In SHIP-1, 25(OH)D levels were positively associated with all considered parameters of cardiopulmonary exercise capacity. Subjects with high 25(OH)D levels (4th quartile) showed an up to 25 % higher exercise capacity compared with subjects with low 25(OH)D levels (1st quartile). All associations were replicated in the independent SHIP-TREND cohort and were independent of age, sex, season and other interfering factors. In conclusion, significant positive associations between 25(OH)D and parameters of CPET were detected in two large cohorts of healthy adults.
We have loved this book for more than forty years. Age cannot wither its intellectual charms, nor custom stale its endless teachability, especially in graduate seminars. As in any long relationship, there have been moments of vexation and irritation, but we return to this book over and over to be nourished anew by its originality, its insights, and its capacity not just to evoke a certain kind of German community but also to convince us that the values of such communities shaped much of German history right into the nineteenth and twentieth centuries.
The IntCal09 and Marine09 radiocarbon calibration curves have been revised utilizing newly available and updated data sets from 14C measurements on tree rings, plant macrofossils, speleothems, corals, and foraminifera. The calibration curves were derived from the data using the random walk model (RWM) used to generate IntCal09 and Marine09, which has been revised to account for additional uncertainties and error structures. The new curves were ratified at the 21st International Radiocarbon conference in July 2012 and are available as Supplemental Material at www.radiocarbon.org. The database can be accessed at http://intcal.qub.ac.uk/intcal13/.
High-quality data from appropriate archives are needed for the continuing improvement of radiocarbon calibration curves. We discuss here the basic assumptions behind 14C dating that necessitate calibration and the relative strengths and weaknesses of archives from which calibration data are obtained. We also highlight the procedures, problems, and uncertainties involved in determining atmospheric and surface ocean 14C/12C in these archives, including a discussion of the various methods used to derive an independent absolute timescale and uncertainty. The types of data required for the current IntCal database and calibration curve model are tabulated with examples.
We are interested in the stability of the localized stationary solutions of a three-component reaction-diffusion system with one activator and two inhibitors. We show that depending on control parameters, solutions in form of moving and breathing localized structures can be observed in the vicinity of the codimension-two bifurcation point. We analyze this situation performing multiple scale perturbation expansion in the vicinity of the bifurcation point and derive a set of order parameter equations, explicitly describing the dynamics of the single localized structure. Numerical simulations are carried out, showing good agreement with the analytical predictions.
Due to the collapse of the socialist systems in 1989, Cuba's government promoted a series of structural changes to deal with resource scarcity and to enhance agricultural productivity. The upcoming crisis triggered adaptation strategies and led to a large-scale transition process towards a more sustainable model of agriculture. Farmers' experiments have been an implicit part of this process. Nowadays, farmers' capacity to experiment is widely accepted among the scientific community. However, detailed descriptions of farmers' approaches to experimentation are scarce. In this study, we examine the topics, resources, sources, motives, methods and outcomes of farmers' experiments in Cuba. The research methods comprised semi-structured interviews with 72 Cuban farmers, field notes, participant observation and a research diary. Key informants and 34 expert interviews added important insights into analysis. The results reveal that farmers' experiments are an integral part of farming in Cuba. Most farmers reported realizing their own experiments on their farms. The use of locally available resources was a crucial element for farmers' experiments. The topics were related to the introduction of new plant species or varieties, plant production, mechanization, fertilization, plant protection and the introduction of new animal species. The farmers' own idea was the most important source for experimenting, followed by ideas offered by colleagues and family members. Increasing production, independence from external resources and improving farm management were the main motives for experimenting. More than half of the farmers started to experiment without detailed written or mental planning, but made some considerations about the experiment before starting. Some planned more in detail and a few farmers devised a written plan, draft or model. Starting on a small scale was a way to minimize risks. The experiments were mainly evaluated by observation and comparison. Only a few farmers took records of their experiments. The most important outcomes were higher production, food self-sufficiency, work easement, improved plant health, increased knowledge, higher working efficiency and better taste of products. Farmers' experiments are a means of learning and they enhance farmers' capacity to adapt to changing conditions.
Ultrafast time resolved transmission electron diffraction (TED) in a reflection geometry was used to study the cooling behavior of self-organized, well defined nanoscale germanium hut and dome clusters on Si(001). The clusters were heated in a pump-probe scheme by fs-laser pulses. The resulting transient temperature rise was then determined from the drop in diffraction intensity caused by the Debye-Waller effect. From a cooling time of τ =177 ps we estimated a strongly reduced heat transfer compared with homogeneous films of equivalent thickness.
Innovations are the driving force for agricultural development under present diverse situations of uncertainty. The innovation system perspective acknowledges the contributions made by all stakeholders involved in knowledge development, dissemination and appropriation. According to the specific agricultural production system, farmers adopt innovations, modify them or innovate on their own. This paper examines the role of farmers' experiments and innovations in Cuba's agricultural innovation system (AIS), identifies knowledge exchange encounters and describes some strategies implemented to institutionalize farmers' experiments and innovations. The research methods comprised 34 semi-structured interviews with agricultural experts from the science, administration and advisory system, and 31 free list questionnaires to assess the institutional influence on farmers' experiments and innovations. In addition, three case studies of outstanding farmers' experiments are presented. The results suggest that the government's commitment to social participation in knowledge development provides the basic prerequisite for an effective integration of farmers' experiments and innovation in Cuba. The historically conditioned vertical structure of knowledge development and dissemination is gradually changing toward more horizontal procedures. The dynamic exchange of ideas at all kinds of interactive meetings, such as workshops or farmers' field schools, have favored farmer to farmer learning as well as knowledge sharing with research, academic and extension officials. This multi-stakeholders' approach contributes to institutionalize farmers' knowledge. Farmers' experiments and innovations play a major role in improving farm management and thereby can contribute to build resilience at the farming system level as well as for the national agricultural system.
We argue that detonations of sub-Chandrasekhar mass white dwarfs can lead to bright explosions with light curves and spectra similar to those of observed Type Ia supernovae. Given that binary systems containing accreting sub-Chandrasekhar mass white dwarfs should be common, this suggests that a non-negligible fraction of the observed Type Ia supernova rate may arise from sub-Chandrasekhar mass explosions, if they can be ignited. We discuss aspects of how such explosions might be realized in nature and both merits and challenges associated with invoking sub-Chandrasekhar mass explosion models to account for observed Type Ia supernovae.
The interaction between turbulence in a minimal supersonic channel and radiative heat transfer is studied using large-eddy simulation. The working fluid is pure water vapour with temperature-dependent specific heats and molecular transport coefficients. Its line spectra properties are represented with a statistical narrow-band correlated-k model. A grey gas model is also tested. The parallel no-slip channel walls are treated as black surfaces concerning thermal radiation and are kept at a constant temperature of 1000 K. Simulations have been performed for different optical thicknesses (based on the Planck mean absorption coefficient) and different Mach numbers. Results for the mean flow variables, Reynolds stresses and certain terms of their transport equations indicate that thermal radiation effects counteract compressibility (Mach number) effects. An analysis of the total energy balance reveals the importance of radiative heat transfer, compared to the turbulent and mean molecular heat transport.
X-ray powder diffraction data for CuGa0.15In0.85Se2 and CuGa0.50In0.50Se2 are reported. Indexing of the X-ray diffraction powder pattern and the Rietveld refinement confirmed that these compounds crystallize in the tetragonal crystal system, with space group I-42d (No. 122) and lattice parameters of a=5.7528(2) Å and c=11.5225(3) Å for CuGa0.15In0.85Se2 and a=5.6847(1) Å and c=11.2817(1) Å for CuGa0.50In0.50Se2. The CuGaxIn1−xSe2 system presents the chalcopyrite type crystal structure (CuFeS2) and corresponds to two stacked zinc-blende unit cells. The metal atoms Cu, In, and Ga are regularly ordered in the unit cell. Every Se atom is tetrahedrally bonded to two Cu and two In and Ga atoms.
The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0–12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org.
The Supernova Working Group was re-established at the IAU XXV General Assembly in Sydney, 21 July 2003, sponsored by Commissions 28 (Galaxies) and 47 (Cosmology). Here we report on some of its activities since 2005.
An outbreak of haemolytic uraemic syndrome (HUS) among children caused by infection with sorbitol-fermenting enterohaemorrhagic Escherichia coli O157:H− (SF EHEC O157:H−) occurred in Germany in 2002. This pathogen has caused several outbreaks so far, yet its reservoir and routes of transmission remain unknown. SF EHEC O157:H− is easily missed as most laboratory protocols target the more common sorbitol non-fermenting strains. We performed active case-finding, extensive exploratory interviews and a case-control study. Clinical and environmental samples were screened for SF EHEC O157:H− and the isolates were subtyped by pulsed-field gel electrophoresis. We identified 38 case-patients in 11 federal states. Four case-patients died during the acute phase (case-fatality ratio 11%). The case-control study could not identify a single vehicle or source. Further studies are necessary to identify the pathogen's reservoir(s). Stool samples of patients with HUS should be tested with an adequate microbiological set-up to quickly identify SF EHEC O157:H−.