272 research outputs found

    Canada as the Target of GDR Espionage

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    German Democratic Republic (GDR) diplomatic missions included a legal residentur: an intelligence service base whose presence was more or less openly acknowledged. This was staffed by the Hauptverwaltung A (HVA - Main Directorate Foreign Intelligence), one of the principal divisions within the Ministerium für Staatssicherheit (Ministry for State Security). The HVA’s main task was espionage. While most of the HVA files have been destroyed, the HVA had created a special database which holds all of the information it produced between 1969 and 1989. This database allows us to identify which source delivered what information and when, who received the information, and what value each piece of information had. The GDR’s Canadian embassy did not open until 1987, and due to the short term of its existence the HVA residentur in Canada could hardly have played a significant intelligence role. And we can almost be certain that it did not build up and manage an unofficial spy network from Canada. In fact, the HVA appears to have acquired its knowledge about Canada primarily from other sources, mainly agents within the West German foreign ministry and from other partner intelligence agencies. The GDR had undoubtedly deep insights into the domestic and foreign affairs of Canada. They were well informed about the role Canada played within NATO and within the Helsinki Accord. Within Canada, regulations governing everyday life were of primary concern, indicating that the country was being used as an operational spearhead. Knowledge about the Canadian intelligence services was fragmentary and selective, but also very accurate. Although there has been no evidence concerning East German spies in Canada, we cannot definitely conclude that there were none. Only the Canadian Security Intelligence Service can shed light on that

    Operations and Performance of the PACS Instrument 3He Sorption Cooler on board of the Herschel Space Observatory

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    A 3He sorption cooler produced the operational temperature of 285mK for the bolometer arrays of the Photodetector Array Camera and Spectrometer (PACS) instrument of the Herschel Space Observatory. This cooler provided a stable hold time between 60 and 73h, depending on the operational conditions of the instrument. The respective hold time could be determined by a simple functional relation established early on in the mission and reliably applied by the scientific mission planning for the entire mission. After exhaustion of the liquid 3He due to the heat input by the detector arrays, the cooler was recycled for the next operational period following a well established automatic procedure. We give an overview of the cooler operations and performance over the entire mission and distinguishing in-between the start conditions for the cooler recycling and the two main modes of PACS photometer operations. As a spin-off, the cooler recycling temperature effects on the Herschel cryostat 4He bath were utilized as an alternative method to dedicated Direct Liquid Helium Content Measurements in determining the lifetime of the liquid Helium coolant.Comment: 34 pages, 13 figures, accepted in Experimental Astronom

    State of the art of nanocrystals – special features, production, nanotoxicology aspects and intracellular delivery

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    Drug nanocrystals are the latest, broadly introduced nanoparticulate carrier to the pharmaceutical market from the year 2000 onwards. The special features of nanocrystals for the delivery of poorly soluble drugs are briefly reviewed (saturation solubility, dissolution velocity, adhesiveness). The industrially relevant bottom up (precipitation) and top down production technologies (pearl milling, high pressure homogenization, combination technologies) are presented. As nanotoxicological aspects, the effect of size, degradability versus biopersistency and intracellular uptake are discussed, classifying the nanocrystals in the low/non-risk group. Intracellular uptake plays a minor or no role for dermal and oral nanocrystals, but it plays a key role for intravenously injected nanocrystals (e.g. nevirapine, paclitaxel, itraconazole). Uptake by the macrophages of the mononuclear phagocytic system (MPS, liver spleen) can modify/optimize blood profiles via prolonged release from the MPS (itraconazole), but also target toxicity by too high organ concentrations and thus cause nanotoxicity. The balance in the competitive intracellular uptake by MPS and the target cells (e.g. blood–brain barrier) decides about therapeutic efficiency. The concept of “differential protein adsorption” to modulate this balance is shown for its applicability to nanocrystals for intracellular delivery to the cells of the blood–brain barrier (atovaquone)

    New low surface brightness dwarf galaxies in the Centaurus group

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    Context. The distribution of satellite galaxies around the Milky Way and Andromeda and their correlation in phase space pose a major challenge to the standard ΛCDM model of structure formation. Other nearby groups of galaxies are now being scrutinized to test for the ubiquity of the phenomenon. Aims. We conducted an extensive CCD imaging survey for faint, unresolved dwarf galaxies of very low surface brightness in the whole Centaurus group region, encompassing the Cen A and M 83 subgroups lying at a distance of roughly 4 and 5 Mpc, respectively. The aim is to significantly increase the sample of known Centaurus group members down to a fainter level of completeness, serving as a basis for future studies of the 3D structure of the group. Methods. Following our previous survey of 60 square degrees covering the M 83 subgroup, we extended and completed our survey of the Centaurus group region by imaging another 500 square degrees area in the g and r bands with the wide-field Dark Energy Survey camera at the 4 m Blanco telescope at CTIO. The surface brightness limit reached for unresolved dwarf galaxies is μr ≈ 29 mag arcsec-2. The faintest suspected Centaurus members found have mr ≈ 19.5 mag or Mr ≈ −8.8 mag at the mean distance of the group. The images were enhanced using different filtering techniques. Results. We found 41 new dwarf galaxy candidates, which together with the previously discovered 16 dwarf candidates in the M 83 subgroup amounts to almost a doubling of the number of known galaxies in the Centaurus complex, if the candidates are confirmed. We carried out surface photometry in g and r, and report the photometric parameters derived therefrom, for all new candidates as well as previously known members in the surveyed area. The photometric properties of the candidates, when compared to those of Local Group dwarfs and previously known Centaurus dwarfs, suggest membership in the Centaurus group. The sky distribution of the new objects is generally following a common envelope around the Cen A and M 83 subgroups. How the new dwarfs are connected to the intriguing double-planar feature recently reported must await distance information for the candidatesO.M. and B.B. are grateful to the Swiss National Science Foundation for financial support. H.J. acknowledges the support of the Australian Research Council through Discovery projects DP120100475 and DP150100862

    Collective Electronic Excitation Coupling between Planar Optical Lattices using Ewald's Method

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    Using Ewald's summation method we investigate collective electronic excitations (excitons) of ultracold atoms in parallel planar optical lattices including long range interactions. The exciton dispersion relation can then be suitably rewritten and efficiently calculated for long range resonance dipole-dipole interactions. Such in-plane excitons resonantly couple for two identical optical lattices, with an energy transfer strength decreasing exponentially with the distance between the lattices. This allows a restriction of the transfer to neighboring planes and gives rise to excitons delocalized between the lattices. In general equivalent results will hold for any planar system containing lattice layers of optically active and dipolar materials.Comment: 6 pages, and 7 figure

    The M 101 group complex: New dwarf galaxy candidates and spatial structure

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    Context. The fine details of the large-scale structure in the local Universe provide important empirical benchmarks for testing cosmological models of structure formation. Dwarf galaxies are key object for such studies. Aims. Our aim was to enlarge the sample of known dwarf galaxies in the local Universe. We performed a search for faint unresolved low-surface-brightness dwarf galaxies in the M 101 group complex, including the region around the major spiral galaxies M 101, M 51, and M 63 lying at a distance of 7.0, 8.6, and 9.0 Mpc, respectively. The new dwarf galaxy sample can be used in a first step to test for significant substructure in the 2D distribution and in a second step to study the spatial distribution of the galaxy complex. Methods. Using filtering algorithms we surveyed 330 square degrees of imaging data obtained from the Sloan Digital Sky Survey. The images were visually inspected. The spatial distribution of known galaxies and candidates was analyzed and the system transformed into a M 101 eigenframe using the geometrical alignment of the group. Results. We discovered 15 new dwarf galaxies and carried out surface photometry in the g and r bands. The similarity of the photometric properties of these dwarfs to those of Local Group dwarfs suggest membership to the M 101 group complex. The sky distribution of the candidates follows the thin planar structure outlined by the known members of the three subgroups. The ~3 Mpc long filamentary structure has a rms thickness of 67 kpc. The planar structure of the embedded M 101 subgroup is even thinner, with rms = 46 kpc. The formation of this structure might be due to the expansion of the bordering Local Void. Other implications are discussed as well. Conclusions. We show the viability of SDSS data to extend the sample of dwarfs in the local Universe and test cosmological models on small scales

    Infectious complications and graft outcome following treatment of acute antibody-mediated rejection after kidney transplantation: A nationwide cohort study.

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    Acute antibody-mediated rejection (AMR) remains a challenge after kidney transplantation (KT). As there is no clear-cut treatment recommendation, accurate information on current therapeutic strategies in real-life practice is needed. KT recipients from the multicenter Swiss Transplant Cohort Study treated for acute AMR during the first post-transplant year were included retrospectively. We aimed at describing the anti-rejection protocols used routinely, as well as patient and graft outcomes, with focus on infectious complications. Overall, 65/1669 (3.9%) KT recipients were treated for 75 episodes of acute AMR. In addition to corticosteroid boluses, most common therapies included plasmapheresis (56.0%), intravenous immunoglobulins (IVIg) (38.7%), rituximab (25.3%), and antithymocyte globulin (22.7%). At least one infectious complication occurred within 6 months from AMR treatment in 63.6% of patients. Plasmapheresis increased the risk of overall (hazard ratio [HR]: 2.89; P-value = 0.002) and opportunistic infection (HR: 5.32; P-value = 0.033). IVIg exerted a protective effect for bacterial infection (HR: 0.29; P-value = 0.053). The recovery of renal function was complete at 3 months after AMR treatment in 67% of episodes. One-year death-censored graft survival was 90.9%. Four patients (6.2%) died during the first year (two due to severe infection). In this nationwide cohort we found significant heterogeneity in therapeutic approaches for acute AMR. Infectious complications were common, particularly among KT recipients receiving plasmapheresis

    Field-induced phase transition in Bi1/2Na1/2TiO3-based lead-free piezoelectric ceramics

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    The origin of the electric field-induced strain in the polycrystalline ceramic 0.92Bi(1/2)Na(1/2)TiO(3)-0.06BaTiO(3)-0.02K(1/2)Na(1/2)NbO(3) was investigated using in situ high-resolution X-ray and neutron diffraction techniques. The initially existing tetragonal phase with pseudocubic lattice undergoes a reversible phase transition to a significantly distorted rhombohedral phase under electric field, accompanied by a change in the oxygen octahedral tilting from a 0 a 0 c + to a - a - a - and in the tilting angle. The polarization values for the tetragonal and rhombohedral phases were calculated based on the structural information from Rietveld refinements. The large recoverable electric field-induced strain is a consequence of a reversible electric field-induced phase transition from an almost nonpolar tetragonal phase to a ferroelectrically active rhombohedral phase.open686

    Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

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    BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London
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