Zeolite-dye micro lasers

We present a new class of micro lasers based on nanoporous molecular sieve host-guest systems. Organic dye guest molecules of 1-Ethyl-4-(4-(p-Dimethylaminophenyl)-1,3-butadienyl)-pyridinium Perchlorat were inserted into the 0.73-nm-wide channel pores of a zeolite AlPO$_4$-5 host. The zeolitic micro crystal compounds where hydrothermally synthesized according to a particular host-guest chemical process. The dye molecules are found not only to be aligned along the host channel axis, but to be oriented as well. Single mode laser emission at 687 nm was obtained from a whispering gallery mode oscillating in a 8-$\mu$m-diameter monolithic micro resonator, in which the field is confined by total internal reflection at the natural hexagonal boundaries inside the zeolitic microcrystals.Comment: Accepted for publication in Phys. Rev. Let

Cellular Automata Simulating Experimental Properties of Traffic Flows

A model for 1D traffic flow is developed, which is discrete in space and time. Like the cellular automaton model by Nagel and Schreckenberg [J. Phys. I France 2, 2221 (1992)], it is simple, fast, and can describe stop-and-go traffic. Due to its relation to the optimal velocity model by Bando et al. [Phys. Rev. E 51, 1035 (1995)], its instability mechanism is of deterministic nature. The model can be easily calibrated to empirical data and displays the experimental features of traffic data recently reported by Kerner and Rehborn [Phys. Rev. E 53, R1297 (1996)].Comment: For related work see http://www.theo2.physik.uni-stuttgart.de/helbing.html and http://traffic.comphys.uni-duisburg.de/member/home_schreck.htm

A redshifted Fe Kα\alpha line from the unusual gamma-ray source PMN J1603-4904

Multiwavelength observations have revealed the highly unusual properties of the gamma-ray source PMN J1603-4904, which are difficult to reconcile with any other well established gamma-ray source class. The object is either a very atypical blazar or compact jet source seen at a larger angle to the line of sight. In order to determine the physical origin of the high-energy emission processes in PMN J1603-4904, we study the X-ray spectrum in detail. We performed quasi-simultaneous X-ray observations with XMM-Newton and Suzaku in 2013 September, resulting in the first high signal-to-noise X-ray spectrum of this source. The 2-10 keV X-ray spectrum can be well described by an absorbed power law with an emission line at 5.44$\pm$0.05 keV (observed frame). Interpreting this feature as a K{\alpha} line from neutral iron, we determine the redshift of PMN J1603-4904 to be z=0.18$\pm$0.01, corresponding to a luminosity distance of 872$\pm$54 Mpc. The detection of a redshifted X-ray emission line further challenges the original BL Lac classification of PMN J1603-4904. This result suggests that the source is observed at a larger angle to the line of sight than expected for blazars, and thus the source would add to the elusive class of gamma-ray loud misaligned-jet objects, possibly a {\gamma}-ray bright young radio galaxy.Comment: 5 pages, 1 figure, A&A accepte

Phytochrome Mediated Responses in Agrobacterium fabrum: Growth, Motility and Plant Infection

The soil bacterium and plant pathogen Agrobacterium fabrum C58 has two phytochrome photoreceptors, Agp1 and Agp2. We found that plant infection and tumor induction by A. fabrum is down-regulated by light and that phytochrome knockout mutants of A. fabrum have diminished infection rates. The regulation pattern of infection matches with that of bacterial conjugation reported earlier, suggesting similar regulatory mechanisms. In the regulation of conjugation and plant infection, phytochromes are active in darkness. This is a major difference to plant phytochromes, which are typically active after irradiation. We also found that propagation and motility were affected in agp1− and agp2− knockout mutants, although propagation was not always affected by light. The regulatory patterns can partially but not completely be explained by modulated histidine kinase activities of Agp1 and Agp2. In a mass spectrometry-based proteomic study, 24 proteins were different between light and dark grown A. fabrum, whereas 382 proteins differed between wild type and phytochrome knockout mutants, pointing again to light independent roles of Agp1 and Agp2

Shaping The Future: Developing Principles for Policy Recommendations for Responsible Innovation in Virtual Worlds

As Extended Reality (XR) technologies continue to evolve at a rapid pace, they hold the promise of transforming the way we interact both with digital information and the physical world. Whilst Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR) technologies offer unbridled opportunities for social connections, productivity, and play, these rapid technological advancements also pose critical challenges to ethics, privacy, accessibility, and safety. At present, there is little policy documentation that directly addresses the novel affordances posed by XR technologies, leading to a ‘policy void’ in this space. Having clear and effective policy frameworks prior to the widespread adoption of technology encourages and enables responsible and ethical innovation of XR technologies. This workshop is therefore dedicated to developing forward-thinking principles to guide policy recommendations that address potential future vulnerabilities posed by the widespread adoption of XR technologies whilst simultaneously encouraging the responsible innovation of new advancements within XR. To ensure these policy recommendations promote responsible innovation, the workshop will assemble multidisciplinary academics, industry developers and international policymakers. Our goal is to ensure that all perspectives are considered such that we can collaboratively chart a responsible and sustainable course for the XR landscape

Shaping the Future:Developing Principles for Policy Recommendations for Responsible Innovation in Virtual Worlds

As Extended Reality (XR) technologies continue to evolve at a rapid pace, they hold the promise of transforming the way we interact both with digital information and the physical world. Whilst Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR) technologies offer unbridled opportunities for social connections, productivity, and play, these rapid technological advancements also pose critical challenges to ethics, privacy, accessibility, and safety. At present, there is little policy documentation that directly addresses the novel affordances posed by XR technologies, leading to a 'policy void' in this space. Having clear and effective policy frameworks prior to the widespread adoption of technology encourages and enables responsible and ethical innovation of XR technologies. This workshop is therefore dedicated to developing forward-thinking principles to guide policy recommendations that address potential future vulnerabilities posed by the widespread adoption of XR technologies whilst simultaneously encouraging the responsible innovation of new advancements within XR. To ensure these policy recommendations promote responsible innovation, the workshop will assemble multidisciplinary academics, industry developers and international policymakers. Our goal is to ensure that all perspectives are considered such that we can collaboratively chart a responsible and sustainable course for the XR landscape.</p

Shaping the Future:Developing Principles for Policy Recommendations for Responsible Innovation in Virtual Worlds

As Extended Reality (XR) technologies continue to evolve at a rapid pace, they hold the promise of transforming the way we interact both with digital information and the physical world. Whilst Augmented Reality (AR), Virtual Reality (VR), and Mixed Reality (MR) technologies offer unbridled opportunities for social connections, productivity, and play, these rapid technological advancements also pose critical challenges to ethics, privacy, accessibility, and safety. At present, there is little policy documentation that directly addresses the novel affordances posed by XR technologies, leading to a 'policy void' in this space. Having clear and effective policy frameworks prior to the widespread adoption of technology encourages and enables responsible and ethical innovation of XR technologies. This workshop is therefore dedicated to developing forward-thinking principles to guide policy recommendations that address potential future vulnerabilities posed by the widespread adoption of XR technologies whilst simultaneously encouraging the responsible innovation of new advancements within XR. To ensure these policy recommendations promote responsible innovation, the workshop will assemble multidisciplinary academics, industry developers and international policymakers. Our goal is to ensure that all perspectives are considered such that we can collaboratively chart a responsible and sustainable course for the XR landscape.</p

AN ENHANCED ALGORITHM FOR AUTOMATIC RADIOMETRIC HARMONIZATION OF HIGH-RESOLUTION OPTICAL SATELLITE IMAGERY USING PSEUDOINVARIANT FEATURES AND LINEAR REGRESSION

The growing number of available optical remote sensing data providing large spatial and temporal coverage enables the coherent and gapless observation of the earth’s surface on the scale of whole countries or continents. To produce datasets of that size, individual satellite scenes have to be stitched together forming so-called mosaics. Here the problem arises that the different images feature varying radiometric properties depending on the momentary acquisition conditions. The interpretation of optical remote sensing data is to a great extent based on the analysis of the spectral composition of an observed surface reflection. Therefore the normalization of all images included in a large image mosaic is necessary to ensure consistent results concerning the application of procedures to the whole dataset. In this work an algorithm is described which enables the automated spectral harmonization of satellite images to a reference scene. As the stable and satisfying functionality of the proposed algorithm was already put to operational use to process a high number of SPOT-4/-5, IRS LISS-III and Landsat-5 scenes in the frame of the European Environment Agency's Copernicus/GMES Initial Operations (GIO) High-Resolution Layer (HRL) mapping of the HRL Forest for 20 Western, Central and (South)Eastern European countries, it is further evaluated on its reliability concerning the application to newer Sentinel-2 multispectral imaging products. The results show that the algorithm is comparably efficient for the processing of satellite image data from sources other than the sensor configurations it was originally designed for

Single-vehicle data of highway traffic - a statistical analysis

In the present paper single-vehicle data of highway traffic are analyzed in great detail. By using the single-vehicle data directly empirical time-headway distributions and speed-distance relations can be established. Both quantities yield relevant information about the microscopic states. Several fundamental diagrams are also presented, which are based on time-averaged quantities and compared with earlier empirical investigations. In the remaining part time-series analyses of the averaged as well as the single-vehicle data are carried out. The results will be used in order to propose objective criteria for an identification of the different traffic states, e.g. synchronized traffic.Comment: 12 pages, 19 figures, RevTe