4,943 research outputs found
A comparative study of the energetic performance of climate adaptive facades compared to static facade design in a Mediterranean climate
Energy-efficient design of building façades has so far predominantly been confined to static rigid forms. Recently however, attempts have been made to design environmentally responsive façades, hereby called Climate Adaptive Façades. These have the potential to better address the occupant's requirements, while also reducing energy demand. The present paper focuses on adaptable glazed façades, in a Mediterranean climate. It investigates the simulated energy performance of three types of climate-responsive façades that could be retrofitted to an existing glazed façade, in the process comparing the results to using comparable static façades solutions. Modelling dynamic façades is not an easy task and currently no single building performance simulation package appears to be capable of completely modelling the behaviour of these façades. For this reason a number of simulation packages had to be used to determine the energy demand required to achieve comfortable indoor thermal and lighting conditions. Through the results obtained, it was possible to compare energy demand of a dual-façade design approach, dynamic vs. static, thus identifying general trends. The results also highlight the fact that in order to improve over the predicted performance further studies using specialised tools capable of modelling such novel technologies are required.peer-reviewe
Fuzzy-import hashing:A malware analysis approach
Malware has remained a consistent threat since its emergence, growing into a plethora of types and in large numbers. In recent years, numerous new malware variants have enabled the identification of new attack surfaces and vectors, and have become a major challenge to security experts, driving the enhancement and development of new malware analysis techniques to contain the contagion. One of the preliminary steps of malware analysis is to remove the abundance of counterfeit malware samples from the large collection of suspicious samples. This process assists in the management of man and machine resources effectively in the analysis of both unknown and likely malware samples. Hashing techniques are one of the fastest and efficient techniques for performing this preliminary analysis such as fuzzy hashing and import hashing. However, both hashing methods have their limitations and they may not be effective on their own, instead the combination of two distinctive methods may assist in improving the detection accuracy and overall performance of the analysis. This paper proposes a Fuzzy-Import hashing technique which is the combination of fuzzy hashing and import hashing to improve the detection accuracy and overall performance of malware analysis. This proposed Fuzzy-Import hashing offers several benefits which are demonstrated through the experimentation performed on the collected malware samples and compared against stand-alone techniques of fuzzy hashing and import hashing
Design and Flight Demonstration Test of a Continuous Descent Approach Procedure for Louisville International Airport
A design methodology based on the principles of system analysis was used to design a noise abatement
approach procedure for Louisville International Airport. In a flight demonstration test, this procedure was
shown to reduce the noise at seven locations along the flight path by 3.9 to 6.5 dBA and reduce the fuel
consumed during approach by 400 to 500 lbs. The noise reduction is significant given that a 3-decibel
difference represents a 50% reduction in acoustic energy and is noticeable to the human ear, and the 7%
reduction in the size of the 50 DNL contour that would result if all aircraft were to perform the procedure.
The fuel saving is also significant given the financial benefit to airlines and the accompanying reduction in
gaseous and particulate emissions. While the analysis of aircraft performance data showed how pilot
delay, in combination with auto-throttle and flight management system logic, can result in deviations from
the desired trajectory, the results confirm that near-term implementation of this advanced noise
abatement procedure is possible. The results also provide ample motivation for proposed pilot cueing
solutions and low-noise guidance features in flight management systems
Improving Brain Delivery of Biomolecules via BBB Modulation in Mouse and Rat: Detection using MRI, NIRF, and Mass Spectrometry
There is an urgent need to develop new and alternative methods to deliver functional biomolecules to the brain for diagnosis and treatment of brain diseases. The goal of this study was to evaluate the activity of blood-brain barrier (BBB) modulators (i.e., HAV and ADT peptides) to deliver functional biomolecules (i.e., galbumin, IRdye800cw-cLABL, and cIBR7) to the brains of mice and rats. HAV6, cHAVc3, and ADTC5 peptides but not HAV4 peptide significantly enhanced the brain delivery of 65 kDa galbumin compared to control in Balb/c mice as quantified by magnetic resonance imaging (MRI). Ten-minute pretreatment with ADTC5 peptide still significantly increased brain delivery of galbumin; however, no enhancement was observed after 10-min pretreatment with HAV6. There was no enhancement of galbumin deposition following 40-min pretreatment with ADTC5 or HAV6, suggesting a short duration of the BBB opening for large molecules. ADTC5 peptide also improved the brain delivery of IRdye800cw-cLABL peptide about 3.5-fold compared to control in Balb/c mice as detected by near infrared fluorescence (NIRF). The BBB modulator activity of ADTC5 to deliver cIBR7 peptide was also evaluated in vivo using Sprague-Dawley rats. The amount of cIBR7 in the brain was detected by LC-MS/MS. ADTC5 peptide enhanced the delivery of cIBR7 peptide into rat brain about 4-fold compared to control and the intact cIBR7 can be efficiently extracted and detected in rat brain. In conclusion, HAV and ADT peptides enhance the brain delivery of functional peptides (e.g., cLABL and cIBR7) and protein (e.g., 65 kDa galbumin) in two animal models, and the duration of the BBB opening for a large molecule (e.g., galbumin) was short
Effect of intermittent preventive treatment for malaria during infancy on serological responses to measles and other vaccines used in the Expanded Programme on Immunization: results from five randomised controlled trials.
BACKGROUND: Intermittent preventive treatment for malaria during infancy (IPTi) is the administration of a full therapeutic course of antimalarial drugs to infants living in settings where malaria is endemic, at the time of routine vaccination in the first year of life. We investigated whether IPTi with sulfadoxine-pyrimethamine or other antimalarial drug combinations adversely affected serological responses to vaccines used in the Expanded Programme on Immunization (EPI). METHODS: The study was done in a subset of children enrolled in five randomised controlled trials in Navrongo, Ghana; Kilimanjaro, Tanzania; Manhica, Mozambique; Kisumu, Kenya; and Bungoma, Kenya. All infants presenting for the second dose of the diphtheria-tetanus-pertussis vaccination (given at 8-10 weeks of age) were eligible, and analyses included all children who had received measles vaccination (at 9 months of age) and at least one dose of IPTi or placebo. Blood samples were collected before and after vaccination, and antibody titres were measured by plaque reduction neutralisation (measles, yellow fever), microneutralisation (polio serotypes 1 and 3), and ELISA (all other EPI antigens). Laboratory personnel were unaware of the randomisation groups. We compared the proportion of infants in the IPTi and placebo groups who did not attain protective antibody titres after vaccination, using a one-sided significance non-inferiority margin of 5% for measles (the primary endpoint) and 10% for other EPI antigens. FINDINGS: Between September, 2000, and May, 2008, 8416 children were enrolled in the five studies. Paired samples from 2368 children from sites where sulfadoxine-pyrimethamine was compared with placebo were analysed for measles antibodies. 464 children with detectable measles antibody in their sample before vaccination were excluded, leaving 1904 individuals (934 placebo and 970 sulfadoxine-pyrimethamine) in the study. IPTi with sulfadoxine-pyrimethamine did not have a clinically significant effect on immune responses to measles vaccine; 61 of 970 (6·3%) children who received IPTi did not develop a protective antibody response after measles vaccination compared with 60 of 934 (6·4%) who received placebo, a difference of -0·14% (95% CI -2·3 to 2·1). When other antimalarial drugs were used for IPTi the results were much the same. Among 2396 children from whom serological response data for other EPI antigens were available, we identified no evidence of an adverse effect of IPTi with sulfadoxine-pyrimethamine or other antimalarial drugs on the proportion achieving protective antibody concentrations. INTERPRETATION: IPTi with sulfadoxine-pyrimethamine does not affect serological responses to EPI vaccines. This analysis, therefore, supports the WHO recommendation for coadministration of IPTi with sulfadoxine-pyrimethamine to infants at the time of the second and third doses of DTP and measles vaccination, in areas of sub-Saharan Africa with moderate to high malaria transmission and where malaria parasites are sensitive to these drugs. It also suggests that treatment of clinical malaria at or around the time of vaccination does not compromise vaccine responsiveness. FUNDING: Bill & Melinda Gates Foundation
Modulation of Intercellular Junctions by Cyclic-ADT Peptides as a Method to Reversibly Increase Blood-Brain Barrier Permeability
It is challenging to deliver molecules to the brain for diagnosis and treatment of brain diseases. This is primarily due to the presence of the blood-brain barrier (BBB), which restricts the entry of many molecules into the brain. In this study, cyclic ADT peptides (ADTC1, ADTC5, and ADTC6) have been shown to modify the BBB to enhance the delivery of marker molecules (e.g., 14C-mannitol, Gd-DTPA) to the brain via the paracellular pathways of the BBB. The hypothesis is that these peptides modulate cadherin interactions in the adherens junctions of the vascular endothelial cells forming the BBB to increase paracellular drug permeation. In vitro studies indicated that ADTC5 had the best profile to inhibit adherens junction resealing in MDCK cell monolayers in a concentration-dependent manner (IC50 = 0.3 mM) with a maximal response at 0.4 mM. Under the current experimental conditions, ADTC5 improved the delivery of 14C-mannitol to the brain about twofold compared to the negative control in the in situ rat brain perfusion model. Furthermore, ADTC5 peptide increased in vivo delivery of Gd-DTPA to the brain of Balb/c mice when administered intravenously (i.v.). In conclusion, ADTC5 has the potential to improve delivery of diagnostic and therapeutic agents to the brain
Propagation impairments modeling and QoS parameters characterization in a Ka-band videoconferencing system
The project was funded by the EU 6th Framework Programme (FP6) project TWISTER.Multimedia and Videoconferencing applications transmitted over satellite links are being pushed towards higher frequency bands where more usable bandwidth is present. The service availability of Ka-band satellite links is subject to considerable uncertainty, relying on channel phenomena such as interference and the unpredictability of local weather. This paper presents a model of the interference and the propagation impairments in Ka-band satellite communication systems. Moreover, a description of a simple method which may be used to derive quality of service (QoS) parameters is given.peer-reviewe
The influence of photovoltaics on roof thermal performance - an analysis of convective heat transfer coefficients
In a Mediterranean climate, given the absence of snow, flat roofs are typical of both vernacular and modern architecture. Thermal mass, cross ventilation and night time cooling are standard passive design aids that inhibit indoor temperature build-up on hot summer days. Such flat roofs provide a golden opportunity for free-orientation of PV (photovoltaic) panels, unlike pitched roofs. There is established scientific evidence that their presence on flat roofs also helps curtail surface temperatures of the heavy mass structure, by means of (i) solar shading and (ii) convective cooling at given angles. Both factors in turn lower the convective heat transfer coefficient (CHTC) of the roof structure, thus inhibiting early seasonal temperature build-up. This contributes to lower cooling loads, thus reducing both the carbon footprint of the building as well as lowering energy costs for the owners. Such a holistic contribution is deemed to uphold the social, environmental and economic challenges of today. This study purports to do just that. Through CFD (computational fluid dynamics) this study investigates the effect of flow fields over a typical flat roof building mass in a free field for a range of wind velocities. Results indicate that for a higher wind speed, the convective cooling is more significant than at lower wind speeds. This will in turn influence the elemental U-value of the roof structure, thus reducing cooling loads indoors.peer-reviewe
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