294 research outputs found
Compound flood events: analysing the joint occurrence of extreme river discharge events and storm surges in northern and central Europe
The simultaneous occurrence of extreme events gained more and more attention from scientific research in the last couple of years.
Compared to the occurrence of single extreme events, co-occurring or compound extremes may substantially increase risks.
To adequately address such risks, improving our understanding of compound flood events in Europe is necessary and requires reliable estimates of their probability of occurrence together with potential future changes.
In this study compound flood events in northern and central Europe were studied using a Monte Carlo-based approach that avoids the use of copulas.
Second, we investigate if the number of observed compound extreme events is within the expected range of 2 standard deviations of randomly occurring compound events. This includes variations of several parameters to test the stability of the identified patterns. Finally, we analyse if the observed compound extreme events had a common large-scale meteorological driver.
The results of our investigation show that rivers along the west-facing coasts of Europe experienced a
higher amount of compound flood events than expected by pure chance.
In these regions, the vast majority of the observed compound flood events seem to be related to the cyclonic westerly general weather pattern (Großwetterlage).</p
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Sensitive quantitative detection/identification of infectious Cryptosporidium parvum oocysts by signature lipid biomarker analysis
Unique signature lipid biomarkers were found in the acid-fast oocytes of Cryptosporidium parvum. This makes possible the rapid detection/identification and potential infectivity directly from drinking water membrane filtrates
Seamless integration of the coastal ocean in global marine carbon cycle modeling
We present the first global ocean-biogeochemistry model that uses a telescoping high resolution for an improved representation of coastal carbon dynamics: ICON-Coast. Based on the unstructured triangular grid topology of the model, we globally apply a grid refinement in the land-ocean transition zone to better resolve the complex circulation of shallow shelves and marginal seas as well as ocean-shelf exchange. Moreover, we incorporate tidal currents including bottom drag effects, and extend the parameterizations of the model's biogeochemistry component to account explicitly for key shelf-specific carbon transformation processes. These comprise sediment resuspension, temperature-dependent remineralization in the water column and sediment, riverine matter fluxes from land including terrestrial organic carbon, and variable sinking speed of aggregated particulate matter. The combination of regional grid refinement and enhanced process representation enables for the first time a seamless incorporation of the global coastal ocean in model-based Earth system research. In particular, ICON-Coast encompasses all coastal areas around the globe within a single, consistent ocean-biogeochemistry model, thus naturally accounting for two-way coupling of ocean-shelf feedback mechanisms at the global scale. The high quality of the model results as well as the efficiency in computational cost and storage requirements proves this strategy a pioneering approach for global high-resolution modeling. We conclude that ICON-Coast represents a new tool to deepen our mechanistic understanding of the role of the land-ocean transition zone in the global carbon cycle, and to narrow related uncertainties in global future projections
Side-by-Side Testing of Commercial Office Lighting Systems: Two-lamp Fluorescent Fixtures
Lighting systems in commercial office
buildings are primary determinants of building
energy use. In warmer climates, lighting energy use
has important implications for building cooling loads
as well as those directly associated with illumination
tasks. To research the comparative performance of
conventional and advanced office lighting systems,
Florida Solar Energy Center (FSEC) set up the
Lighting Flexible Test Facility (LFTF) which allows
side-by-side comparison of lighting options in two
otherwise identical 2.7 m x 3.7 m (9' x 12') south
facing offices.
The ceiling of the LFTF contains 0.61 m x
1.2 m (2' x 4') recessed fluorescent fixtures designed
to be easily changed. Differing lighting systems were
comparatively tested against each other over weeklong
periods. Data on power consumption (watts),
power quality (power factor), work-plane interior
lighting levels (lux), bulb-wall, fixture and plenum
temperatures were recorded every 15 minutes on a
multi-channel data logger. This data allows realistic
analysis of comparative lighting system performance
including interactions with daylighting
A Mosquito Pick-and-Place System for PfSPZ-based Malaria Vaccine Production
The treatment of malaria is a global health challenge that stands to benefit
from the widespread introduction of a vaccine for the disease. A method has
been developed to create a live organism vaccine using the sporozoites (SPZ) of
the parasite Plasmodium falciparum (Pf), which are concentrated in the salivary
glands of infected mosquitoes. Current manual dissection methods to obtain
these PfSPZ are not optimally efficient for large-scale vaccine production. We
propose an improved dissection procedure and a mechanical fixture that
increases the rate of mosquito dissection and helps to deskill this stage of
the production process. We further demonstrate the automation of a key step in
this production process, the picking and placing of mosquitoes from a staging
apparatus into a dissection assembly. This unit test of a robotic mosquito
pick-and-place system is performed using a custom-designed micro-gripper
attached to a four degree of freedom (4-DOF) robot under the guidance of a
computer vision system. Mosquitoes are autonomously grasped and pulled to a
pair of notched dissection blades to remove the head of the mosquito, allowing
access to the salivary glands. Placement into these blades is adapted based on
output from computer vision to accommodate for the unique anatomy and
orientation of each grasped mosquito. In this pilot test of the system on 50
mosquitoes, we demonstrate a 100% grasping accuracy and a 90% accuracy in
placing the mosquito with its neck within the blade notches such that the head
can be removed. This is a promising result for this difficult and non-standard
pick-and-place task.Comment: 12 pages, 11 figures, Manuscript submitted for Special Issue of IEEE
CASE 2019 for IEEE T-AS
T-Cell activation: a queuing theory analysis at low agonist density
We analyze a simple linear triggering model of the T-cell receptor (TCR) within the framework of queuing theory, in which TCRs enter the queue upon full activation and exit by downregulation. We fit our model to four experimentally characterized threshold activation criteria and analyze their specificity and sensitivity: the initial calcium spike, cytotoxicity, immunological synapse formation, and cytokine secretion. Specificity characteristics improve as the time window for detection increases, saturating for time periods on the timescale of downregulation; thus, the calcium spike (30 s) has low specificity but a sensitivity to single-peptide MHC ligands, while the cytokine threshold (1 h) can distinguish ligands with a 30% variation in the complex lifetime. However, a robustness analysis shows that these properties are degraded when the queue parameters are subject to variation—for example, under stochasticity in the ligand number in the cell-cell interface and population variation in the cellular threshold. A time integration of the queue over a period of hours is shown to be able to control parameter noise efficiently for realistic parameter values when integrated over sufficiently long time periods (hours), the discrimination characteristics being determined by the TCR signal cascade kinetics (a kinetic proofreading scheme). Therefore, through a combination of thresholds and signal integration, a T cell can be responsive to low ligand density and specific to agonist quality. We suggest that multiple threshold mechanisms are employed to establish the conditions for efficient signal integration, i.e., coordinate the formation of a stable contact interface
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