508 research outputs found
Intents de tragèdia. Sobre tres escenificacions de Heiner Müller al Deutsches Theater de Berlín
Concepts and Components for Pulsed Angle Modulated Ultra Wideband Communication and Radar Systems
Peptidoglycan Recognition Protein 4 Limits Bacterial Clearance and Inflammation in Lungs by Control of the Gut Microbiota
Modellierung und Messung von Emissionen an Transceiverpins in Automotive-System-ICs, verursacht durch integrierte DC/DC-Wandler
Die Integration von DC/DC-Wandlern mit Transceivern in Automotive-System-ICs führt zu neuen Herausforderungen im Bezug auf die Einhaltung der Emissionsgrenzwerte an den Transceiverpins. An einem Test-IC werden die Emissionen des DC/DC-Wandlers an verschiedenen Transceiverpins ermittelt. Der Substratübertragungspfad wird mit Hilfe eines neuartigen Substratextraktors modelliert, und zur Beschreibung induktiver Bonddrahtkopplungen wird ein HFSS-Packagemodell verwendet. Der Vergleich zwischen Modellvorhersage und Messung zeigt typ. eine Abweichung von unter _6 dB bis 1 GHz
Investigation of a Second Exhaust Valve Lift to Improve Combustion in a Methane - Diesel Dual-Fuel Engine
In recent years, the utilization of dual-fuel combustion has gained
popularity in order to improve engine efficiency and emissions. With
its high knock resistance, methane allows operation in high
compression diesel engines with lower risk of knocking. With the use
of diesel fuel as an ignition source, it is possible to exploit the
advantages of lean combustion without facing problems to provide
the high amount of ignition energy necessary to burn methane under
such operating conditions. Another advantage is the variety of
sources from which the primary fuel can be obtained. In addition to
fossil sources, methane can also be produced from biomass or
electrical energy.
As the rate of substitution of diesel by methane increases, the trade-
off between nitrogen oxide and soot is mitigated. However, emissions
of carbon monoxide and unburned methane increase. Since carbon
monoxide is toxic and methane has 25 times the global warming
potential of carbon dioxide, these emission components pose a
problem. Because of the stability of the molecule, methane catalysts
require an exhaust gas temperature of over 500 °C in order to work
effectively.
In this work, the effect of conventional cooled external exhaust gas
recirculation (EGR) and additional hot internal EGR are investigated
for different substitution rates in a nonroad tractor engine converted
to dual-fuel operation. The internal EGR rate is controlled by a
variable second exhaust valve lift during the intake stroke – an
approach which promises to benefit dual-fuel engines by increasing
the in-cylinder gas temperature, thus favoring more complete
combustion. A simulation model of the engine is used to determine
the internal EGR rates and in-cylinder temperatures based on the
experimental data. When internal EGR is used in combination with
external EGR, the resulting emissions show additional reductions in
nitrogen oxide (up to -51 %), carbon monoxide (up to -18 %) and
methane (up to -28 %) with increasing internal EGR, while still
maintaining low soot levels due to the substitution of diesel fuel for
methane
A dataset of clinically recorded radar vital signs with synchronised reference sensor signals
Using Radar it is possible to measure vital signs through clothing or a mattress from the distance. This allows for a very comfortable way of continuous monitoring in hospitals or home environments. The dataset presented in this article consists of 24 h of synchronised data from a radar and a reference device. The implemented continuous wave radar system is based on the Six-Port technology and operates at 24 GHz in the ISM band. The reference device simultaneously measures electrocardiogram, impedance cardiogram and non-invasive continuous blood pressure. 30 healthy subjects were measured by physicians according to a predefined protocol. The radar was focused on the chest while the subjects were lying on a tilt table wired to the reference monitoring device. In this manner five scenarios were conducted, the majority of them aimed to trigger hemodynamics and the autonomic nervous system of the subjects. Using the database, algorithms for respiratory or cardiovascular analysis can be developed and a better understanding of the characteristics of the radar-recorded vital signs can be gained
The scale of population structure in Arabidopsis thaliana
The population structure of an organism reflects its evolutionary history and influences its evolutionary trajectory. It constrains the combination of genetic diversity and reveals patterns of past gene flow. Understanding it is a prerequisite for detecting genomic regions under selection, predicting the effect of population disturbances, or modeling gene flow. This paper examines the detailed global population structure of Arabidopsis thaliana. Using a set of 5,707 plants collected from around the globe and genotyped at 149 SNPs, we show that while A. thaliana as a species self-fertilizes 97% of the time, there is considerable variation among local groups. This level of outcrossing greatly limits observed heterozygosity but is sufficient to generate considerable local haplotypic diversity. We also find that in its native Eurasian range A. thaliana exhibits continuous isolation by distance at every geographic scale without natural breaks corresponding to classical notions of populations. By contrast, in North America, where it exists as an exotic species, A. thaliana exhibits little or no population structure at a continental scale but local isolation by distance that extends hundreds of km. This suggests a pattern for the development of isolation by distance that can establish itself shortly after an organism fills a new habitat range. It also raises questions about the general applicability of many standard population genetics models. Any model based on discrete clusters of interchangeable individuals will be an uneasy fit to organisms like A. thaliana which exhibit continuous isolation by distance on many scales
A new role for histone demethylases in the maintenance of plant genome integrity
Histone modifications deposited by the Polycomb repressive complex 2 (PRC2) play a critical role in the control of growth, development, and adaptation to environmental fluctuations of most multicellular eukaryotes. The catalytic activity of PRC2 is counteracted by Jumonji-type (JMJ) histone demethylases, which shapes the genomic distribution of H3K27me3. Here, we show that two JMJ histone demethylases in Arabidopsis, EARLY FLOWERING 6 (ELF6) and RELATIVE OF EARLY FLOWERING 6 (REF6), play distinct roles in H3K27me3 and H3K27me1 homeostasis. We show that failure to reset these chromatin marks during sexual reproduction results in the transgenerational inheritance of histone marks, which cause a loss of DNA methylation at heterochromatic loci and transposon activation. Thus, Jumonji-type histone demethylases play a dual role in plants by helping to maintain transcriptional states through development and safeguard genome integrity during sexual reproduction
- …