632 research outputs found
Who Creates Jobs? Econometric Modeling and Evidence for Austrian Firm Level Data
This paper offers an empirical analysis of net job creation patterns at the firm level for the Austrian economy between 1993 and 2013 focusing on the impact of firm size and age. We propose a new estimation strategy based on a two-part model. This allows to identify the structural parameters of interest and to decompose behavioral differences between exiting and surviving firms. Our findings suggest that conditional on survival, young Austrian firms experience the largest net job creation rates. Differences in firm size are not able to explain variation in net job creation rates among the group of continuing enterprises. Job destruction induced by market exit, however, is largest among the young and small firms with this effect being even more pronounced during the times of the Great Recession. In order to formulate sensible policy recommendations, a separate treatment of continuing versus exiting firms as proposed by the new two-part model estimation approach seems crucial.(authors' abstract)Series: Department of Economics Working Paper Serie
Characterization of Hamamatsu 64-channel TSV SiPMs
The Hamamatsu UV-light enhanced 64-channel SiPM array of the newest
generation (S13361-3050AS-08) has been examined for the purpose of being used
for the Silicon Elementary Cell Add-on (SiECA) of the EUSO-SPB balloon
experiment. Characterization measurements have been performed with the newly
installed Single Photon Calibration Stand at KIT (SPOCK). The results of the
characterization measurements including the breakdown voltage, the gain, the
PDE, the dark-count rate and the crosstalk probability of all 64 SiPM channels
are presented. Additional measurements of the SiPM sensitivity to photons with
wavelengths lower than 400nm show an improved PDE for small wavelengths
compared to the SiPM array S12642-0808PA-50, which was also investigated for
comparison. The response dynamics have been investigated for low numbers of
incoming photons. Temperature dependent measurements of the gain, the PDE, the
dark-count rate and the crosstalk probability have been performed for one
channel of the SiPM array.Comment: Accepted for publication in Nuclear Instruments and Methods
Enantioselective reduction of sulfur-containing cyclic imines through biocatalysis
Zumbrägel N, Merten C, Huber SM, Gröger H. Enantioselective reduction of sulfur-containing cyclic imines through biocatalysis. Nature Communications. 2018;9(1): 1949
Biological CO2-Methanation: an Approach to Standardization
Power-to-Methane as one part of Power-to-Gas has been recognized globally as one of the key elements for the transition towards a sustainable energy system. While plants that produce methane catalytically have been in operation for a long time, biological methanation has just reached industrial pilot scale and near-term commercial application. The growing importance of the biological method is reflected by an increasing number of scientific articles describing novel approaches to improve this technology. However, these studies are difficult to compare because they lack a coherent nomenclature. In this article, we present a comprehensive set of parameters allowing the characterization and comparison of various biological methanation processes. To identify relevant parameters needed for a proper description of this technology, we summarized existing literature and defined system boundaries for Power-to-Methane process steps. On this basis, we derive system parameters providing information on the methanation system, its performance, the biology and cost aspects. As a result, three different standards are provided as a blueprint matrix for use in academia and industry applicable to both, biological and catalytic methanation. Hence, this review attempts to set the standards for a comprehensive description of biological and chemical methanation processes
Analysis and in situ characterization of activated sludge communities capable of benzotriazole biodegradation
Regenwurmpopulation in ökologisch und integriert bewirtschafteten Agroforstsystemen
Agroforestry systems provide numerous environmental services. One of the advantages is the increase of biodiversity. Earthworms play a major role in soil fertility and have a key function in ecosystems. Abundance, biomass and the amount of species was measured to quantify the influences of trees on the earthworm population in integrated and organic farming systems. Results showed that in poplar stands the amount of earthworms, especially juvenile, was higher than in winter wheat or lucerne-clover-grass fields. Furthermore the organic farming system had higher earthworm abundance and species richness than the integrated farming system. Regarding tree species poplar had fewer earthworms in total and fewer epigeic species
Cortical lamina-dependent blood volume changes in human brain at 7T
Cortical layer-dependent high (sub-millimeter) resolution functional magnetic resonance imaging (fMRI) in human or animal brain can be used to address questions regarding the functioning of cortical circuits, such as the effect of different afferent and efferent connectivities on activity in specific cortical layers. The sensitivity of gradient echo (GE) blood oxygenation level-dependent (BOLD) responses to large draining veins reduces its local specificity and can render the interpretation of the underlying laminar neural activity impossible. The application of the more spatially specific cerebral blood volume (CBV)-based fMRI in humans has been hindered by the low sensitivity of the noninvasive modalities available. Here, a vascular space occupancy (VASO) variant, adapted for use at high field, is further optimized to capture layer-dependent activity changes in human motor cortex at sub-millimeter resolution. Acquired activation maps and cortical profiles show that the VASO signal peaks in gray matter at 0.8–1.6 mm depth, and deeper compared to the superficial and vein-dominated GE-BOLD responses. Validation of the VASO signal change versus well-established iron-oxide contrast agent based fMRI methods in animals showed the same cortical profiles of CBV change, after normalization for lamina-dependent baseline CBV. In order to evaluate its potential of revealing small lamina-dependent signal differences due to modulations of the input-output characteristics, layer-dependent VASO responses were investigated in the ipsilateral hemisphere during unilateral finger tapping. Positive activation in ipsilateral primary motor cortex and negative activation in ipsilateral primary sensory cortex were observed. This feature is only visible in high-resolution fMRI where opposing sides of a sulcus can be investigated independently because of a lack of partial volume effects. Based on the results presented here, we conclude that VASO offers good reproducibility, high sensitivity and lower sensitivity than GE-BOLD to changes in larger vessels, making it a valuable tool for layer-dependent fMRI studies in humans
ABOVEGROUND WOODY BIOMASS PRODUCTION OF DIFFERENT TREE SPECIES IN SILVOARABLE AGROFORESTRY SYTEMS WITH ORGANIC AND INTEGRATED CULTIVATION IN SOUTHERN GERMANY
The increasing demand for bioenergy and the combination of agricultural production with conservation has made agroforestry to a sustainable land-management option. Aboveground woody biomass plays a decisive role considering the economic value of the agroforestry systems as well as the carbon storage. With the objective to study aboveground woody biomass production of agroforestry systems with different cultivation methods (organic/ integrated), short rotation plantations of different tree species were established 2009 and coppiced in 2012. The studied tree species were black alder (Alnus glutinosa), black locust (Robinia pseudoacacia), poplar “Max 3”, (Populus maximowiczii x Populus nigra) and willow “Inger” (Salix triandra x Salix viminalis). At the end of each growing season biomass production was estimated by an allometric model that predicted individual tree biomass from stem diameter. At the end of the rotation biomass was estimated directly by harvesting. Biomass production ranged from 3.9 to 10.9 tDM ha-1a-1 with poplar and locust having highest growth rates. Significant variation was observed between tree species, but not between management (organic/ integrated), what indicates that organic and integrated agroforestry systems can have a comparable tree biomass production. Small-scale differences of the soil caused high intraspecific variation and suggest the inclusion of further soil investigations
A human macrophage – hepatocyte co-culture model for comparative studies of infection and replication of Francisella tularensis LVS strain and subspecies holarctica and mediasiatica
Detection of intracellular LPS in macrophage / hepatocyte co-cultures infected with LVS (open bars), spp. holarctica (grey filled bars) or spp. mediasiatica (black filled bars) and untreated control (hatched bars). A) Different amounts of macrophages in the co-culture were tested (6, 12 and 22Â % of macrophages on total cell count). Flow cytometric detection of intracellular LPS in macrophages (MFI mean fluorescence intensity); B-D) percentage of remaining detectable macrophages after infection of the co-cultures with B) 6Â % macrophages/94Â % hepatocytes, C) 12Â % macrophages/ 88Â % hepatocytes and D) 22Â % macrophages/ 88Â % hepatocytes 72Â h post infection. (TIF 32735Â kb
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