1,713 research outputs found
Stochastic evaluation of sewer inlet capacity on urban pluvial flooding
In this paper we present an innovative methodology to stochastically assess the impact of sewer inlet conditions on urban pluvial flooding. The results showed that sewer inlet capacity can have a large impact on the occurrence of urban pluvial flooding. The methodology is a useful tool for dealing with uncertainties in sewer inlet operational conditions and contribute to comprehensive assessment of urban pluvial risk assessment
On the possibility of calibrating urban storm-water drainage models using gauge-based adjusted radar rainfall estimates
Traditionally, urban storm water drainage models have been calibrated using only raingauge data, which may result in overly conservative models due to the lack of spatial description of rainfall. With the advent of weather radars, radar rainfall estimates with higher temporal and spatial resolution have become increasingly available and have started to be used operationally for urban storm water model calibration and real time operation. Nonetheless, the insufficient accuracy of radar rainfall estimates has proven problematic and has hindered its widespread practical use. This work explores the possibility of improving the applicability of radar rainfall estimates to the calibration of urban storm-water drainage models by employing gauge-based radar rainfall adjustment techniques. Four different types of rainfall estimates were used as input to the recently verified urban storm water drainage models of the Beddington catchment in South London; these included: raingauge, block-kriged raingauge, radar (UK Met Office Nimrod) and the adjusted (or merged) radar rainfall estimates. The performance of the simulated flow and water depths was assessed using measurements from 78 gauges. Results suggest that a better calibration could be achieved by using the block-kriged raingauge and the adjusted radar estimates as input, as compared to using only radar or raingauge estimates
A rapide method for separation of adults in a mixed population of Steinernema carpocapsae (Nematoda : Steinernematidae)
La sélection d'un grand nombre de nématodes viables est une condition impérative pour les études sur la physiologie de #Steinernema carpocapsae$. Est décrite ici une méthode rapide et pratique permettant la séparation des mâles et des femelles de ce nématode à partir d'une suspension contenant une population brute. Pour l'utilisation de cette méthode, la densité des mâles et des femelles est déterminée par application de la loi de Stokes modifiée. Les adultes sont séparés dans un gradient discontinu de saccharose s'étageant de 10 et 20%. Quatre-vingt quinze pour cent des mâles et des femelles isolés grâce à cette méthode restent viables. (Résumé d'auteur
Observations of Reconnection Flows in a Flare on the Solar Disk
Magnetic reconnection is a well-accepted part of the theory of solar eruptive
events, though the evidence is still circumstantial. Intrinsic to the
reconnection picture of a solar eruptive event, particularly in the standard
model for two-ribbon flares ("CSHKP" model), are an advective flow of
magnetized plasma into the reconnection region, expansion of field above the
reconnection region as a flux rope erupts, retraction of heated
post-reconnection loops, and downflows of cooling plasma along those loops. We
report on a unique set of SDO/AIA imaging and Hinode/EIS spectroscopic
observations of the disk flare SOL2016-03-23T03:54 in which all four flows are
present simultaneously. This includes spectroscopic evidence for a plasma
upflow in association with large-scale expanding closed inflow field. The
reconnection inflows are symmetric, and consistent with fast reconnection, and
the post-reconnection loops show a clear cooling and deceleration as they
retract. Observations of coronal reconnection flows are still rare, and most
events are observed at the solar limb, obscured by complex foregrounds, making
their relationship to the flare ribbons, cusp field and arcades formed in the
lower atmosphere difficult to interpret. The disk location and favorable
perspective of this event have removed these ambiguities giving a clear picture
of the reconnection dynamics.Comment: 9 pages, 5 figures, and 1 table. Accepted for publication in ApJ
Enhancement of urban pluvial flood risk management and resilience through collaborative modelling: a UK case study
This paper presents the main findings and lessons learned from the development and implementation of a new methodology for collaborative modelling, social learning and social acceptance of flood risk management technologies. The proposed methodology entails three main phases: (1) stakeholder analysis and engagement; (2) improvement of urban pluvial flood modelling and forecasting tools; and (3) development and implementation of web-based tools for collaborative modelling in flood risk management and knowledge sharing. The developed methodology and tools were tested in the Cranbrook catchment (London Borough of Redbridge, UK), an area that has experienced severe pluvial (surface) flooding in the past. The developed methodologies proved to be useful for promoting interaction between stakeholders, developing collaborative modelling and achieving social acceptance of new technologies for flood risk management. Some limitations for stakeholder engagement were identified and are discussed in the present paper
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Evolution of the eyes of vipers with and without infrared-sensing pit organs
We examined lens and brille transmittance, photoreceptors, visual pigments, and visual opsin gene sequences of viperid snakes with and without infrared-sensing pit organs. Ocular media transmittance is high in both groups. Contrary to previous reports, small as well as large single cones occur in pit vipers. Non-pit vipers differ from pit vipers in having a twotiered retina, but few taxa have been examined for this poorly understood feature. All vipers sampled express rh1, sws1 and lws visual opsin genes. Opsin spectral tuning varies but not in accordance with the presence/absence of pit organs, and not always as predicted from gene sequences. The visual opsin genes were generally under purifying selection, with positive selection at spectral tuning amino acids in RH1 and SWS1 opsins, and at retinal pocket stabilization sites in RH1 or LWS (and without substantial differences between pit and nonpit vipers). Lack of evidence for sensory trade-off between viperid eyes (in the aspects examined) and pit organs might be explained by the high degree of neural integration of vision and infrared detection; the latter representing an elaboration of an existing sense with addition of a novel sense organ, rather than involving the evolution of a wholly novel sensory system
Cystic tumor of the atrioventricular node of the heart appears to be the heart equivalent of the solid cell nests (ultimobranchial rests) of the thyroid
We studied a series of 10 solid cell nests (SCNs) of the thyroid and a case of cystic tumor of the atrioventricular node (CTAVN) of the heart and reviewed the literature. The CTAVN and SCNs appeared as cystic and/or solid (squamoid) structures mainly composed of polygonal or oval cells (main cells) admixed with occasional clear cells (neuroendocrine and C cells). Main cells were immunoreactive for simple and stratified epithelial-type cytokeratins, epithelial membrane antigen, carcinoembryonic antigen, carbohydrate antigen 19.9, p63, bcl-2, and galectin-3. Neuroendocrine (and C) cells were positive for simple-type cytokeratins, carcinoembryonic antigen, calcitonin, chromogranin, synaptophysin, and thyroid transcription factor-1. Our data support the hypothesis that the CTAVN of the heart and the SCNs of the thyroid are identical structures that represent the same lesional process. The assumption that CTAVN is a ultimobranchial heterotopia fits with the known role of cardiac neural crest cells in cardiovascular development
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