143 research outputs found
Nueva especie de Nebria Latreille, 1802 de los Montes de León, noroeste de España (Coleoptera, Carabidae: Nebriinae)
Nebria leonensis sp. n. from the Sierras de la Cabrera Baja and del Teleno (southern Montes de León) is described. This species, related to N. lafresnayei Serville, 1821, is characterised by its slender body, long and light brown extremities, the form of its pronotum, and evenly rounded elytra, which are conspicuously flattened on the discus. The differentiating characters and the habitat are described. A determination key to the species and subspecies of the group to which the new species belongs is presented.Se describe Nebria leonensis sp. n. de las sierras de la Cabrera Baja y del Teleno (sur de los Montes de León). Esta especie, relacionada con Nebria lafresnayei Serville, 1821, se caracteriza especialmente por su cuerpo delgado, largas extremidades de color marrón claro, forma del pronoto, y élitros uniformemente redondeados y claramente deprimidos en el disco. Además de describir los caracteres que la definen y el hábitat, se presentan unas breves notas sobre la historia faunística de los montes de León, y una clave de determinación de las especies y subespecies del grupo al que pertenece la nueva especie
Droplet sizing in spray flame synthesis using wide-angle light scattering (WALS)
Abstract
In spray flame synthesis the processes of spray formation and evaporation of the single droplets greatly affect the morphology and size of particles formed. An in situ measurement of these parameters is thus essential for process control and development. In this work, wide-angle light scattering (WALS) is applied to measure droplet sizes in a spray flame. The scattering data of the spherical droplets are evaluated by applying Mie-theory. For droplet sizing, the number of characteristic maxima in the scattering pattern and the measured scattering intensities are evaluated. Droplet size distributions and their parameters were determined by repetitive exposures in various heights above the nozzle outlet for two solvents: pure ethanol and a mixture of ethanol and 2-ethylhexanoic acid at a volume ratio of 35/65. While for ethanol the median droplet size decreases with increasing height, it decreases less for the mixture, which in general exhibits increased droplet sizes for all heights compared to pure ethanol. Furthermore, we could show that using air instead of nitrogen as a co-flow barely affects droplet evaporation in the flame
Exciton and trion dynamics in atomically thin MoSe2 and WSe2: effect of localization
We present a detailed investigation of the exciton and trion dynamics in naturally doped MoSe2 and WSe2 single atomic layers as a function of temperature in the range 10-300K under above band-gap laser excitation. By combining time-integrated and time-resolved photoluminescence (PL) spectroscopy we show the importance of exciton and trion localization in both materials at low temperatures. We also reveal the transition to delocalized exciton complexes at higher temperatures where the exciton and trion thermal energy exceeds the typical localization energy. This is accompanied with strong changes in PL including suppression of the trion PL and decrease of the trion PL life-time, as well as significant changes for neutral excitons in the temperature dependence of the PL intensity and appearance of a pronounced slow PL decay component. In MoSe2 and WSe2 studied here, the temperatures where such strong changes occur are observed at around 100 and 200 K, respectively, in agreement with their inhomogeneous PL linewidth of 8 and 20 meV at T~10K. The observed behavior is a result of a complex interplay between influences of the specific energy ordering of bright and dark excitons in MoSe2 and WSe2, sample doping, trion and exciton localization and various temperature-dependent non-radiative processes
Microservice Transition and its Granularity Problem: A Systematic Mapping Study
Microservices have gained wide recognition and acceptance in software
industries as an emerging architectural style for autonomic, scalable, and more
reliable computing. The transition to microservices has been highly motivated
by the need for better alignment of technical design decisions with improving
value potentials of architectures. Despite microservices' popularity, research
still lacks disciplined understanding of transition and consensus on the
principles and activities underlying "micro-ing" architectures. In this paper,
we report on a systematic mapping study that consolidates various views,
approaches and activities that commonly assist in the transition to
microservices. The study aims to provide a better understanding of the
transition; it also contributes a working definition of the transition and
technical activities underlying it. We term the transition and technical
activities leading to microservice architectures as microservitization. We then
shed light on a fundamental problem of microservitization: microservice
granularity and reasoning about its adaptation as first-class entities. This
study reviews state-of-the-art and -practice related to reasoning about
microservice granularity; it reviews modelling approaches, aspects considered,
guidelines and processes used to reason about microservice granularity. This
study identifies opportunities for future research and development related to
reasoning about microservice granularity.Comment: 36 pages including references, 6 figures, and 3 table
SARS-CoV-2 Wastewater Genomic Surveillance: Approaches, Challenges, and Opportunities
During the SARS-CoV-2 pandemic, wastewater-based genomic surveillance (WWGS)
emerged as an efficient viral surveillance tool that takes into account
asymptomatic cases and can identify known and novel mutations and offers the
opportunity to assign known virus lineages based on the detected mutations
profiles. WWGS can also hint towards novel or cryptic lineages, but it is
difficult to clearly identify and define novel lineages from wastewater (WW)
alone. While WWGS has significant advantages in monitoring SARS-CoV-2 viral
spread, technical challenges remain, including poor sequencing coverage and
quality due to viral RNA degradation. As a result, the viral RNAs in wastewater
have low concentrations and are often fragmented, making sequencing difficult.
WWGS analysis requires advanced computational tools that are yet to be
developed and benchmarked. The existing bioinformatics tools used to analyze
wastewater sequencing data are often based on previously developed methods for
quantifying the expression of transcripts or viral diversity. Those methods
were not developed for wastewater sequencing data specifically, and are not
optimized to address unique challenges associated with wastewater. While
specialized tools for analysis of wastewater sequencing data have also been
developed recently, it remains to be seen how they will perform given the
ongoing evolution of SARS-CoV-2 and the decline in testing and patient-based
genomic surveillance. Here, we discuss opportunities and challenges associated
with WWGS, including sample preparation, sequencing technology, and
bioinformatics methods.Comment: V Munteanu and M Saldana contributed equally to this work A Smith and
S Mangul jointly supervised this work For correspondence:
[email protected]
Determinants of government bond spreads in the euro area: in good times as in bad
Despite the single currency, yields on government bonds in the Euro Area deviate substantially from German bond yields. These bond spreads are usually attributed to differing default and liquidity risks. The empirical literature documents that evaluation of these risks is subject to time variation in global factors approximated by US corporate bond spreads or short term interest rates. Within this paper time variation is modeled via latent processes instead of proxy variables. The findings suggest that default risk measured via expected debt to gross national product ratio explains a major part of the differences in band yields in the Euro area between 2003 and the unfolding of the financial crises. During the financial crises both risks gain importance in explaining bond spreads, with increased relative importance of liquidity risks compared to default risks or their market perception
Conceptual design report for the LUXE experiment
This Conceptual Design Report describes LUXE (Laser Und XFEL Experiment), an experimental campaign that aims to combine the high-quality and high-energy electron beam of the European XFEL with a powerful laser to explore the uncharted terrain of quantum electrodynamics characterised by both high energy and high intensity. We will reach this hitherto inaccessible regime of quantum physics by analysing high-energy electron-photon and photon-photon interactions in the extreme environment provided by an intense laser focus. The physics background and its relevance are presented in the science case which in turn leads to, and justifies, the ensuing plan for all aspects of the experiment: Our choice of experimental parameters allows (i) field strengths to be probed where the coupling to charges becomes non-perturbative and (ii) a precision to be achieved that permits a detailed comparison of the measured data with calculations. In addition, the high photon flux predicted will enable a sensitive search for new physics beyond the Standard Model. The initial phase of the experiment will employ an existing 40 TW laser, whereas the second phase will utilise an upgraded laser power of 350 TW. All expectations regarding the performance of the experimental set-up as well as the expected physics results are based on detailed numerical simulations throughout
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