Phase-matched coherent hard x-rays from relativistic high-order harmonic generation

High-order harmonic generation (HHG) with relativistically strong laser pulses is considered employing electron ionization-recollisions from multiply charged ions in counterpropagating, linearly polarized attosecond pulse trains. The propagation of the harmonics through the medium and the scaling of HHG into the multi-kilo-electronvolt regime are investigated. We show that the phase mismatch caused by the free electron background can be compensated by an additional phase of the emitted harmonics specific to the considered setup which depends on the delay time between the pulse trains. This renders feasible the phase-matched emission of harmonics with photon energies of several tens of kilo-electronvolt from an underdense plasma

A novel vacuum ultra violet lamp for metastable rare gas experiments

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states e.g. for excitation of metastable rare gas atoms. The lamp can be directly mounted to ultra high vacuum vessels (p <= 10^(-10) mbar). It is driven by a 2.45 GHz microwave source. For optimum operation it requires powers of approximately 20 W. The VUV light is transmitted through a magnesium fluoride window, which is known to have a decreasing transmittance for VUV photons with time. In our special setup, after a run-time of the VUV lamp of 550 h the detected signal continuously decreased to 25 % of its initial value. This corresponds to a lifetime increase of two orders of magnitude compared to previous setups or commercial lamps

A novel vacuum ultra violet lamp for metastable rare gas experiments

We report on a new design of a vacuum ultra violet (VUV) lamp for direct optical excitation of high laying atomic states e.g. for excitation of metastable rare gas atoms. The lamp can be directly mounted to ultra high vacuum vessels (p <= 10^(-10) mbar). It is driven by a 2.45 GHz microwave source. For optimum operation it requires powers of approximately 20 W. The VUV light is transmitted through a magnesium fluoride window, which is known to have a decreasing transmittance for VUV photons with time. In our special setup, after a run-time of the VUV lamp of 550 h the detected signal continuously decreased to 25 % of its initial value. This corresponds to a lifetime increase of two orders of magnitude compared to previous setups or commercial lamps

High-Performance Integrated Window and Façade Solutions for California

The researchers developed a new generation of high-performance façade systems and supporting design and management tools to support industry in meeting California’s greenhouse gas reduction targets, reduce energy consumption, and enable an adaptable response to minimize real-time demands on the electricity grid. The project resulted in five outcomes: (1) The research team developed an R-5, 1-inch thick, triplepane, insulating glass unit with a novel low-conductance aluminum frame. This technology can help significantly reduce residential cooling and heating loads, particularly during the evening. (2) The team developed a prototype of a windowintegrated local ventilation and energy recovery device that provides clean, dry fresh air through the façade with minimal energy requirements. (3) A daylight-redirecting louver system was prototyped to redirect sunlight 15–40 feet from the window. Simulations estimated that lighting energy use could be reduced by 35–54 percent without glare. (4) A control system incorporating physics-based equations and a mathematical solver was prototyped and field tested to demonstrate feasibility. Simulations estimated that total electricity costs could be reduced by 9-28 percent on sunny summer days through adaptive control of operable shading and daylighting components and the thermostat compared to state-of-the-art automatic façade controls in commercial building perimeter zones. (5) Supporting models and tools needed by industry for technology R&amp;D and market transformation activities were validated. Attaining California’s clean energy goals require making a fundamental shift from today’s ad-hoc assemblages of static components to turnkey, intelligent, responsive, integrated building façade systems. These systems offered significant reductions in energy use, peak demand, and operating cost in California

The EHR-ARCHE project: Satisfying clinical information needs in a Shared Electronic Health Record System based on IHE XDS and Archetypes

AbstractPurposeWhile contributing to an improved continuity of care, Shared Electronic Health Record (EHR) systems may also lead to information overload of healthcare providers. Document-oriented architectures, such as the commonly employed IHE XDS profile, which only support information retrieval at the level of documents, are particularly susceptible for this problem. The objective of the EHR-ARCHE project was to develop a methodology and a prototype to efficiently satisfy healthcare providers’ information needs when accessing a patient's Shared EHR during a treatment situation. We especially aimed to investigate whether this objective can be reached by integrating EHR Archetypes into an IHE XDS environment.MethodsUsing methodical triangulation, we first analysed the information needs of healthcare providers, focusing on the treatment of diabetes patients as an exemplary application domain. We then designed ISO/EN 13606 Archetypes covering the identified information needs. To support a content-based search for fine-grained information items within EHR documents, we extended the IHE XDS environment with two additional actors. Finally, we conducted a formative and summative evaluation of our approach within a controlled study.ResultsWe identified 446 frequently needed diabetes-specific information items, representing typical information needs of healthcare providers. We then created 128 Archetypes and 120 EHR documents for two fictive patients. All seven diabetes experts, who evaluated our approach, preferred the content-based search to a conventional XDS search. Success rates of finding relevant information was higher for the content-based search (100% versus 80%) and the latter was also more time-efficient (8–14min versus 20min or more).ConclusionsOur results show that for an efficient satisfaction of health care providers’ information needs, a content-based search that rests upon the integration of Archetypes into an IHE XDS-based Shared EHR system is superior to a conventional metadata-based XDS search

The Influence of Strong Ties on the Use of Modern Contraceptives in Kenya

Der nachhaltige Rückgang der Geburtenentwicklung in Kenia ist neben fortschreitenden gesellschaftlichen Prozessen der Modernisierung und Urbanisierung auch auf die vermehrte Nutzung moderner Verfahren der Familienplanung zurückzuführen. Die wachsende Akzeptanz moderner Kontrazeptiva in der kenianischen Gesellschaft ist das Ergebnis eines fortschreitenden Diffusionsprozesses. Informelle kommunikative Beziehungen nehmen in diesem Prozess eine Schlüsselrolle ein, indem Akteure, die bereits moderne Kontrazeptiva nutzen, andere Akteure im Rahmen alltäglicher Kommunikation beeinflussen, diese Methoden ebenfalls zu verwenden. Der Grad dieser Beeinflussung hängt unter anderem davon ab, wie weit Nutzer und potenzielle Nutzer über starke Beziehungen miteinander verbunden sind. Starke Beziehungen sind in Prozessen interpersonaler Beeinflussung von Bedeutung, da sie zum einen Strukturen normativer Handlungserwartungen schaffen und zum anderen Quellen zuverlässiger Informationen sind. Daten über 740 mündlich befragte Kenianische Frauen, die im Rahmen des Kenyan Diffusion and Ideational Change Project gewonnen wurden, stützen die Bedeutung starker Beziehung im Kontext individueller Entscheidungen, moderne Kontrazeptiva zu nutzen oder nicht zu nutzen. Die empirischen Ergebnisse zeigen signifikante Assoziationen zwischen der Wahrscheinlichkeit, dass eine Befragte moderne Kontrazeptiva verwendet, und starken Beziehungen zu Nutzern und Nichtnutzern moderner Kontrazeptiva in ihren kommunikativen Netzwerken. Hierbei ist aber von Bedeutung, zu welchem Personenkreis starke Beziehungen existieren. Starke Beziehungen zu Freunden oder Mitgliedern der Ursprungsfamilie besitzen einen größeren Einfluss als starke Beziehungen zu Personen des unmittelbaren häuslichen Umfelds.The persistent decline of fertility in Kenya has been attributed to increasing modernization and urbanization as well as to the increased use of modern family planning methods. The growing acceptance of modern contraceptives in Kenya is the result of a diffusion process. Informal communication networks are a key factor in this process because as part of day-to-day interaction and communication participants, who already use modern contraception influence others to use these methods. This influence depends - among other things - on the extent to which users of modern contraceptives and potenzial users of these methods are connected by strong ties. In particular, such ties are relevant for social influence because they create structures of normative expectations and constitute sources of reliable information. This paper is based on data from 740 women participating in the Kenyan Diffusion and Ideational Change Project, and our analyses support the role of strong ties for women's decisions to employ modern contraceptives. In particular, the empirical results show significant associations between a woman's probability of using modern contraception and strong ties to users and non-users in her social network. Moreover, our analyses also reveal the particular relevance of the social relationships associated with strong ties. For instance, strong ties to friends or members of the parental family exert a greater influence on contraceptive decisions than strong ties to persons in the immediate household

Accuracy of UAV Photogrammetry in Glacial and Periglacial Alpine Terrain: A Comparison With Airborne and Terrestrial Datasets

Unoccupied Aerial Vehicles (UAVs) equipped with optical instruments are increasingly deployed in high mountain environments to investigate and monitor glacial and periglacial processes. The comparison and fusion of UAV data with airborne and terrestrial data offers the opportunity to analyse spatio-temporal changes in the mountains and to upscale findings from local UAV surveys to larger areas. However, due to the lack of gridded high-resolution data in alpine terrain, the specific challenges and uncertainties associated with the comparison and fusion of multi-temporal data from different platforms in this environment are not well known. Here we make use of UAV, airborne, and terrestrial data from four (peri)glacial alpine study sites with different topographic settings. The aim is to assess the accuracy of UAV photogrammetric products in complex terrain, to point out differences to other products, and to discuss best practices regarding the fusion of multi-temporal data. The surface geometry and characteristic geomorphological features of the four alpine sites are well captured by the UAV data, but the positional accuracies vary greatly. They range from 15 cm (root-mean-square error) for the smallest survey area (0.2 km2) with a high ground control point (GCP) density (40 GCPs km−2) to 135 cm for the largest survey area (>2.5 km2) with a lower GCP density (<10 GCPs km−2). Besides a small number and uneven distribution of GCPs, a low contrast, and insufficient lateral image overlap (<50–70%) seem to be the main causes for the distortions and artefacts found in the UAV data. Deficiencies both in the UAV and airborne data are the reason for horizontal deviations observed between the datasets. In steep terrain, horizontal deviations of a few decimetres may result in surface elevation change errors of several metres. An accurate co-registration and evaluation of multi-temporal UAV, airborne, and terrestrial data using tie points in stable terrain is therefore of utmost importance when it comes to the investigation of surface displacements and elevation changes in the mountains. To enhance the accuracy and quality of UAV photogrammetry, the use of UAVs equipped with multi-spectral cameras and high-precision positioning systems is recommended, especially in rugged terrain and snow-covered areas

Attochirp-free High-order Harmonic Generation

A method is proposed for arbitrarily engineering the high-order harmonic generation phase achieved by shaping a laser pulse and employing xuv light or x rays for ionization. This renders the production of bandwidth-limited attosecond pulses possible while avoiding the use of filters for chirp compensation. By adding the first 8 Fourier components to a sinusoidal field of $10^{16}$W/cm$^2$, the bandwidth-limited emission of 8 as is shown to be possible from a Li$^{2+}$ gas. The scheme is extendable to the zs-scale

Mortality and molecular epidemiology associated with extended-spectrum β-lactamase production in Escherichia coli from bloodstream infection

Background: The rate of infections due to extended-spectrum β-lactamase (ESBL)-producing Escherichia coli is growing worldwide. These infections are suspected to be related to increased mortality. We aimed to estimate the difference in mortality due to bloodstream infections (BSIs) with ESBL-positive and ESBL-negative E. coli isolates and to determine the molecular epidemiology of our ESBL-positive isolates. Materials and methods: We performed a cohort study on consecutive patients with E. coli BSI between 2008 and 2010 at the Charité University Hospital. Collected data were ESBL production, basic demographic parameters, and underlying diseases by the Charlson comorbidity index (CCI). The presence of ESBL genes was analyzed by polymerase chain reaction (PCR) and sequencing. Phylogenetic groups of ESBL-positive E. coli were determined by PCR. Risk factors for mortality were analyzed by multivariable regression analysis. Results: We identified 115 patients with BSI due to E. coli with ESBL phenotype and 983 due to ESBL-negative E. coli. Fifty-eight percent (n=67) of the ESBL-positive BSIs were hospital-acquired. Among the 99 isolates that were available for PCR screening and sequencing, we found mainly 87 CTX-M producers, with CTX-M-15 (n=55) and CTX-M-1 (n=21) as the most common types. Parameters significantly associated with mortality were age, CCI, and length of stay before and after onset of BSI. Conclusion: The most common ESBL genotypes in clinical isolates from E. coli BSIs were CTX-M-15 (58%) and CTX-M-1 (22%). ESBL production in clinical E. coli BSI isolates was not related to increased mortality. However, the common occurrence of hospital-acquired BSI due to ESBL-positive E. coli indicates future challenges for hospitals