328 research outputs found
AI for Situational Awareness in Situations With High Uncertainty: An Explorative Case Study
Often, the police experience scenarios with much uncertainty. These scenarios can be characterized by high time pressure, huge amounts of information, and potentially severe consequences. In this paper, we study whether artificial intelligence (AI) can be a fit for the information processing needs of the police helping them achieve situational awareness and make better decisions. Given the potential severity of police situations, AI can potentially reduce the risk of fatal outcomes and wrong decisions. Investigating this issue with police officers and AI experts as our informants, our findings suggest that our informants are positive to AI as a support tool, but more skeptical to whether AI can make an impact in their daily police work due to the complexity of their work. The importance of implementing AI to suitable tasks is emphasized
Professionshøjskolernes nye rolle inden for forskning og udvikling
I løbet af 2013 blev rammerne for forskning og udvikling (FoU) på professionshøjskolerne ændret markant. Det har betydning for professionshøjskolernes rolle i det danske forsknings- og ud-viklingslandskab. Artiklen tager afsæt i en interessentbaseret forståelse af kvalitet i FoU og analyserer projektet “Tidlig Matematikindsats til Marginalgrupper” ud fra hhv. et aftager-, et studenter- og et forskningsperspektiv. Det konkluderes at centrale karakteristika for professionshøjskolernes FoU vil være orientering mod de samfundsudfordringer professionerne forventes at bidrage til at løse, konkrete bidrag til professionsuddannelserne og tæt samspil med praksis og de øvrige danske forsk-ningsinstitutioner
Role of hydroxylation for the atomic structure of a non-polar vicinal zinc oxide
From the catalytic, semiconducting, and optical properties of zinc oxide (ZnO) numerous potential applications emerge. For the physical and chemical properties of the surface, under-coordinated atoms often play an important role, necessitating systematic studies of their influence. Here we study the vicinal ZnO(10 1 \uaf 4) surface, rich in under-coordinated sites, using a combination of several experimental techniques and density functional theory calculations. We determine the atomic-scale structure and find the surface to be a stable, long-range ordered, non-polar facet of ZnO, with a high step-density and uniform termination. Contrary to an earlier suggested nano-faceting model, a bulk termination fits much better to our experimental observations. The surface is further stabilized by dissociatively adsorbed H2O on adjacent under-coordinated O- and Zn-atoms. The stabilized surface remains highly active for water dissociation through the remaining under-coordinated Zn-sites. Such a vicinal oxide surface is a prerequisite for future adsorption studies with atomically controlled local step and terrace geometry
Soil Bacteria Isolated From Tunisian Arid Areas Show Promising Antimicrobial Activities Against Gram-Negatives
Arid regions show relatively fewer species in comparison to better-watered biomes, but the competition for the few nutrients is very distinct. Here, in total 373 bacterial strains were isolated from rhizospheric soils obtained from three different sampling sites in Tunisia. Their potential for the production of antimicrobial compounds was evaluated. Bacterial strains, showing antibacterial activity against pathogenic bacteria, were isolated from all three sites, one strain from the Bou-Hedma national park, 15 strains from Chott-Djerid, and 13 strains from Matmata, respectively. The dominant genus was Bacillus, with 27 out of 29 strains. Most interestingly, 93% of the isolates showed activity against Gram-positive and Gram-negative test bacteria. Strain Bacillus sp. M21, harboring high inhibitory potential, even against clinical isolates of Gram-negative bacteria, was analyzed in detail to enable purification and identification of the bioactive compound responsible for its bioactivity. Subsequent HPLC-MS and NMR analyses resulted in the identification of 1-acetyl-β-carboline as active component. Furthermore, fungicides of the bacillomycin and fengycin group, which in addition show antibiotic effects, were identified. This work highlights the high potential of the arid-adapted strains for the biosynthesis of specialized metabolites and suggest further investigation of extreme environments, since they constitute a promising bioresource of biologically active compounds
Three-dimensional cometary dust coma modelling in the collisionless regime: strengths and weaknesses
Inverse coma and tail modelling of comets based on the method developed by Finson & Probstein is commonly used to analyse cometary coma images. Models of this type often contain a large number of assumptions that may not be constrained unless wide temporal or spectral coverage is available and the comets are bright and at relatively small geocentric distance. They are used to predict physical parameters, such as the mass distribution of the dust, but rarely give assessments of the accuracy of the estimate. A three-dimensional cometary dust coma model in the collisionless regime has been developed to allow the effectiveness of such models to constrain dust coma properties to be tested. The model is capable of simulating the coma morphology for the following input parameters: the comet nucleus shape, size, rotation, emission function (including active fraction and jets), grain velocity distribution (and dispersion), size distribution, dust production rate, grain material and light scattering from the cometary dust.
Characterization of the model demonstrates that the mass distribution cannot be well constrained as is often assumed; the cumulative mass distribution index ? can only be constrained to within ±0.15. The model is highly sensitive to the input grain terminal velocity distribution so model input can be tested with a large degree of confidence. Complex secondary parameters such as jets, rotation and grain composition all have an effect on the structure of the coma in similar ways, so unique solutions for these parameters cannot be derived from a single optical image alone. Multiple images at a variety of geometries close in time can help constrain these effects.
The model has been applied to photometric observations of comets 126P/IRAS and 46P/Wirtanen to constrain a number of physical properties including the dust production rate and mass distribution index. The derived dust production rate (Qdust) for 46P/Wirtanen was 3+7/1.5 kg s1 at a pre-perihelion heliocentric distance of 1.8 au, and for P/IRAS was 50+100/20 kg s1 at a pre-perihelion heliocentric distance of 1.7 au; both comets exhibited a mass distribution index ? = 0.8 ± 0.15
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