736 research outputs found
Influence of stored aqueous ceftriaxone solutions on colony formation by neutrophil and macrophage precursor cells
Aqueous solutions of ceftriaxone in concentrations similar to those achieved in man and stored at temperatures of 4°C, 22°C and 37°C for up to four weeks were tested in methylcellulose cultures of normal bone marrow from ten donors. No significant differences were detected between the colony formation by neutrophil and macrophage precursors in control cultures and in cultures containing stored ceftriaxone. It is concluded that aqueous ceftriaxone solutions stored for up to four weeks at temperatures up to 37°C are not altered to such an extent that they adversely affect colony formation by bone marrow progenitor cells from healthy donor
Quantifying 3D vegetation structure in wetlands using differently measured airborne laser scanning data
Quantifying 3D vegetation structure in wetlands using differently measured airborne laser scanning data
Strong paleoclimatic legacies in current plant functional diversity patterns across Europe
Numerous studies indicate that environmental changes during the late Quaternary have elicited longâterm disequilibria between species diversity and environment. Despite its importance for ecosystem functioning, the importance of historical environmental conditions as determinants of FD (functional diversity) remains largely unstudied. We quantified the geographic distributions of plant FD (richness and dispersion) across Europe using distribution and functional trait information for 2702 plant species. We then compared the importance of historical and contemporary factors to determine the relevance of past conditions as predictors of current plant FD in Europe. For this, we compared the strength of the relationships between FD with temperature and precipitation stability since the LGM (Last Glacial Maximum), accessibility to LGM refugia, and contemporary environmental conditions (climate, productivity, soil, topography, and land use). Functional richness and dispersion exhibited geographic patterns with strong associations to the environmental history of the region. The effect size of accessibility to LGM refugia and climate stability since the LGM was comparable to that of the contemporary predictors. Both functional richness and dispersion increased with temperature stability since the LGM and accessibility to LGM refugia. Functional richness' geographic pattern was primarily associated with accessibility to LGM refugia growing degreeâdays, land use heterogeneity, diversity of soil types, and absolute minimum winter temperature. Functional dispersion's geographic pattern was primarily associated with accessibility to LGM refugia growing degreeâdays and absolute minimum winter temperature. The high explained variance and model support of historical predictors are consistent with the idea that longâterm variability in environmental conditions supplements contemporary factors in shaping FD patterns at continental scales. Given the importance of FD for ecosystem functioning, future climate change may elicit not just shortâterm shifts in ecosystem functioning, but also longâterm functional disequilibria
Automatic seismic phase picking and consistent observation error assessment: application to the Italian seismicity
Accuracy of seismic phase observation and consistency of timing error assessment define the quality of seismic waves arrival times. High-quality and large data sets are prerequisites for seismic tomography to enhance the resolution of crustal and upper mantle structures. In this paper we present the application of an automated picking system to some 600 000 seismograms of local earthquakes routinely recorded and archived by the Italian national seismic network. The system defines an observation weighting scheme calibrated with a hand-picked data subset and mimics the picking by an expert seismologist. The strength of this automatic picking is that once it is tuned for observation quality assessment, consistency of arrival times is strongly improved and errors are independent of the amount of data to be picked. The application to the Italian local seismicity documents that it is possible to automatically compile a precise, homogeneous and large data set of local earthquake Pg and Pn arrivals with related polarities. We demonstrate that such a data set is suitable for high-precision earthquake location, focal mechanism determination and high-resolution seismic tomograph
Automatic seismic phase picking and consistent observation error assessment: application to Italian seismicity
Accuracy of seismic phase observation and consistency of timing error assessment define the quality of seismic waves arrival times. High-quality and large data sets are prerequisites for seismic tomography to enhance the resolution of crustal and upper mantle structures. In this paperwe present the application of an automated picking system to some 600000 seismograms of local earthquakes routinely recorded and archived by the Italian national seismic network. The system defines an observation weighting scheme calibrated with a hand-picked data subset and mimics the picking by an expert seismologist. The strength of this automatic picking is that once it is tuned for observation quality assessment, consistency of arrival times is strongly improved and errors are independent of the amount of data to be picked. The application to the Italian local seismicity documents that it is possible to automatically compile a precise, homogeneous and large data set of local earthquake Pg and Pn arrivals with related polarities. We demonstrate that such a data set is suitable for high-precision earthquake location, focal mechanism determination and high-resolution seismic tomography
Towards global data products of Essential Biodiversity Variables on species traits
Essential Biodiversity Variables (EBVs) allow observation and reporting of global biodiversity change, but a detailed framework for the empirical derivation of specific EBVs has yet to be developed. Here, we re-examine and refine the previous candidate set of species traits EBVs and show how traits related to phenology, morphology, reproduction, physiology and movement can contribute to EBV operationalization. The selected EBVs express intra-specific trait variation and allow monitoring of how organisms respond to global change. We evaluate the societal relevance of species traits EBVs for policy targets and demonstrate how open, interoperable and machine-readable trait data enable the building of EBV data products. We outline collection methods, meta(data) standardization, reproducible workflows, semantic tools and licence requirements for producing species traits EBVs. An operationalization is critical for assessing progress towards biodiversity conservation and sustainable development goals and has wide implications for data-intensive science in ecology, biogeography, conservation and Earth observation
Measuring frontier orbital energy levels of OLED materials using cyclic voltammetry in solution
The operation of organic light emitting diodes (OLEDs) is governed by a range of material parameters, such as frontier orbital energy levels, charge carrier mobility and excitonic rate parameters. In state-of-the art numerical simulations of OLED devices, more than 30 parameters must be considered to describe the behavior of a multilayer device. Independent measurement techniques to reliably determine each material parameter individually are therefore highly desirable. While several techniques have been established in the OLED community to determine some of them, the highest occupied and lowest unoccupied molecular orbital (HOMO and LUMO) energy levels are not measured or reported on a regular basis, despite their significant influence on device performance. In this work, we show how cyclic voltammetry in solution can be used as a simple technique to measure the HOMO and LUMO energy levels of organic semiconductors. This easily performed experiment allows a fairly accurate estimation of the energy levels of the layers in a device stack. Cyclic voltammetry measurements of four typical OLED materials in solution are presented and their analysis is described in detail to encourage more such measurements in future OLED studies. Four distinctly different voltammograms were obtained, ranging from relatively ideal reversible behavior to a very non-ideal behavior, lacking electrochemical reverse reactions. Two methods for extracting the HOMO and LUMO energy levels from cyclic voltammetry are discussed and compared. The measured HOMO and LUMO levels compare well with reported values measured on thin films, showing that cyclic voltammetry in solution provides a viable means to determine this important, yet underinvestigated material property
NGO Legitimacy: Four Models
The aim of this paper is to examine NGOsâ legitimacy in the context of global politics. In order to yield a better understanding of NGOsâ legitimacy at the international level it is important to examine how their legitimacy claims are evaluated. This paper proposes dividing the literature into four models based on the theoretical and analytical approaches to their legitimacy claims: the market model, social change model, new institutionalism model and the critical model. The legitimacy criteria generated by the models are significantly different in their analytical scope of how one is to assess the role of NGOs operating as political actors contributing to democracy. The paper argues that the models present incomplete, and sometimes conflicting, views of NGOsâ legitimacy and that this poses a legitimacy dilemma for those assessing the political agency of NGOs in world politics. The paper concludes that only by approaching their legitimacy holistically can the democratic role of NGOs be explored and analysed in the context of world politics
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