4,421 research outputs found

    Parity-Violating Electron Scattering and Neucleon Structure

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    The measurement of parity violation in the helicity dependence of electron-nucleon scattering provides unique information about the basic quark structure of the nucleons. In this review, the general formalism of parity-violating electron scattering is presented, with emphasis on elastic electron-nucleon scattering. The physics issues addressed by such experiments is discussed, and the major goals of the presently envisioned experimental program are identified. %General aspects of the experimental technique are reviewed and A summary of results from a recent series of experiments is presented and the future prospects of this program are also discussed.Comment: 45 pages, 9 figure

    DeltaPhish: Detecting Phishing Webpages in Compromised Websites

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    The large-scale deployment of modern phishing attacks relies on the automatic exploitation of vulnerable websites in the wild, to maximize profit while hindering attack traceability, detection and blacklisting. To the best of our knowledge, this is the first work that specifically leverages this adversarial behavior for detection purposes. We show that phishing webpages can be accurately detected by highlighting HTML code and visual differences with respect to other (legitimate) pages hosted within a compromised website. Our system, named DeltaPhish, can be installed as part of a web application firewall, to detect the presence of anomalous content on a website after compromise, and eventually prevent access to it. DeltaPhish is also robust against adversarial attempts in which the HTML code of the phishing page is carefully manipulated to evade detection. We empirically evaluate it on more than 5,500 webpages collected in the wild from compromised websites, showing that it is capable of detecting more than 99% of phishing webpages, while only misclassifying less than 1% of legitimate pages. We further show that the detection rate remains higher than 70% even under very sophisticated attacks carefully designed to evade our system.Comment: Preprint version of the work accepted at ESORICS 201

    Methods for determining the optimal arrangement of water deluge systems on offshore installations

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    Offshore installations are prone to fire and/or explosion accidents. Fires have particularly serious consequences due to their high temperatures and heat flux, which affect humans, structures and environments alike. Due to the hydrocarbon explosions caused by delayed ignition following gas dispersion, fires can be the result of immediate ignition after gas release. Accordingly, it can be difficult to decrease their frequency, which is an element of risk (risk=frequency×consequence), using an active protection system (APS) such as gas detectors capable of shutting down the operation. Thus, it is more efficient to reduce the consequence using a passive protection system (PSS) such as water spray. It is important to decide the number and location of water deluge systems, thus the aim of this study is to introduce a new procedure for optimising the locations of water deluge systems using the water deluge location index (WLI) proposed herein. The locations of water deluge systems are thus optimised based on the results of credible fire scenarios using a three-dimensional computational fluid dynamics (CFD) tool. The effects of water spray and the effectiveness of the WLI are investigated in comparison with uniformly distributed sprays

    Serration phenomena occurring during tensile tests of three high-manganese TWinning Induced Plasticity (TWIP) steels

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    In this study, the serration phenomena of two high-Mn TWIP steels and an Al-added TWIP steel were examined by tensile tests, and were explained by the microstructural evolution including formation of localized Portevin-Le Chatelier deformation bands and twins. In stress-strain curves of the high-Mn steels, serrations started in a fine and short shape, and their height and periodic interval increased with increasing strain, whereas the Al-added steel did not show any serrations. According to digital images of strain rate and strain obtained from a vision strain gage system, deformation bands were initially formed at the upper region of the gage section, and moved downward along the tensile loading direction. The time when the band formation started was matched with the time when one serration occurred in the stress-time curve. This serration behavior was generally explained by dynamic strain aging, which was closely related with the formation of deformation bands. (C) The Minerals, Metals & Materials Society and ASM International 2013ope

    Postural effects of symmetrical and asymmetrical loads on the spines of schoolchildren

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    The school backpack constitutes a daily load for schoolchildren: we set out to analyse the postural effects of this load, considering trunk rotation, shoulder asymmetry, thoracic kyphosis, lumbar lordosis, and sagittal and frontal decompensation from the plumbline. A group of 43 subjects (mean age = 12.5 ± 0.5 years) were considered: average backpack loads and average time spent getting to/from home/school (7 min) had been determined in a previous study conducted on this population. Children were evaluated by means of an optoelectronic device in different conditions corresponding to their usual everyday school backpack activities: without load; bearing 12 (week maximum) and 8 (week average) kg symmetrical loads; bearing an 8 kg asymmetrical load; after fatigue due to backpack carrying (a 7-minute treadmill walking session bearing an 8 kg symmetrical load). Both types of load induce changes in posture: the symmetrical one in the sagittal plane, without statistical significant differences between 8 and 12 kg, and the asymmetrical one in all anatomical planes. Usual fatigue accentuates sagittal effects, but recovery of all parameters (except lumbar lordosis) follows removal of the load. The backpack load effect on schoolchildren posture should be more carefully evaluated in the future, even if we must bear in mind that laws protect workers to carry heavy loads but not children, and results in the literature support the hypothesis that back pain in youngsters is correlated with back pain in adulthoo

    Drop Traffic in Microfluidic Ladder Networks with Fore-Aft Structural Asymmetry

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    We investigate the dynamics of pairs of drops in microfluidic ladder networks with slanted bypasses, which break the fore-aft structural symmetry. Our analytical results indicate that unlike symmetric ladder networks, structural asymmetry introduced by a single slanted bypass can be used to modulate the relative drop spacing, enabling them to contract, synchronize, expand, or even flip at the ladder exit. Our experiments confirm all these behaviors predicted by theory. Numerical analysis further shows that while ladder networks containing several identical bypasses are limited to nearly linear transformation of input delay between drops, mixed combination of bypasses can cause significant non-linear transformation enabling coding and decoding of input delays.Comment: 4 pages, 5 figure

    Oral immunization of haemaggulutinin H5 expressed in plant endoplasmic reticulum with adjuvant saponin protects mice against highly pathogenic avian influenza A virus infection

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    Pandemics in poultry caused by the highly pathogenic avian influenza (HPAI) A virus occur too frequently globally, and there is growing concern about the HPAI A virus due to the possibility of a pandemic among humans. Thus, it is important to develop a vaccine against HPAI suitable for both humans and animals. Various approaches are underway to develop such vaccines. In particular, an edible vaccine would be a convenient way to vaccinate poultry because of the behaviour of the animals. However, an edible vaccine is still not available. In this study, we developed a strategy of effective vaccination of mice by the oral administration of transgenic Arabidopsis plants (HA-TG) expressing haemagglutinin (HA) in the endoplasmic reticulum (ER). Expression of HA in the ER resulted in its high-level accumulation, N-glycosylation, protection from proteolytic degradation and long-term stability. Oral administration of HA-TG with saponin elicited high levels of HA-specific systemic IgG and mucosal IgA responses in mice, which resulted in protection against a lethal influenza virus infection with attenuated inflammatory symptoms. Based on these results, we propose that oral administration of freeze-dried leaf powders from transgenic plants expressing HA in the ER together with saponin is an attractive strategy for vaccination against influenza A virus.X111411Ysciescopu

    Microbiological, histological, immunological, and toxin response to antibiotic treatment in the mouse model of Mycobacterium ulcerans disease.

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    Mycobacterium ulcerans infection causes a neglected tropical disease known as Buruli ulcer that is now found in poor rural areas of West Africa in numbers that sometimes exceed those reported for another significant mycobacterial disease, leprosy, caused by M. leprae. Unique among mycobacterial diseases, M. ulcerans produces a plasmid-encoded toxin called mycolactone (ML), which is the principal virulence factor and destroys fat cells in subcutaneous tissue. Disease is typically first manifested by the appearance of a nodule that eventually ulcerates and the lesions may continue to spread over limbs or occasionally the trunk. The current standard treatment is 8 weeks of daily rifampin and injections of streptomycin (RS). The treatment kills bacilli and wounds gradually heal. Whether RS treatment actually stops mycolactone production before killing bacilli has been suggested by histopathological analyses of patient lesions. Using a mouse footpad model of M. ulcerans infection where the time of infection and development of lesions can be followed in a controlled manner before and after antibiotic treatment, we have evaluated the progress of infection by assessing bacterial numbers, mycolactone production, the immune response, and lesion histopathology at regular intervals after infection and after antibiotic therapy. We found that RS treatment rapidly reduced gross lesions, bacterial numbers, and ML production as assessed by cytotoxicity assays and mass spectrometric analysis. Histopathological analysis revealed that RS treatment maintained the association of the bacilli with (or within) host cells where they were destroyed whereas lack of treatment resulted in extracellular infection, destruction of host cells, and ultimately lesion ulceration. We propose that RS treatment promotes healing in the host by blocking mycolactone production, which favors the survival of host cells, and by killing M. ulcerans bacilli

    Effect of Control Strategies on Prevalence, Incidence and Re-infection of Clonorchiasis in Endemic Areas of China

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    Clonorchiasis is a liver fluke disease prevalent in East Asia, which is transmitted to humans mainly by eating raw freshwater fish. It induces various complications in the liver or bile duct including cholelithiasis, cholecystitis, cholangitis, and cirrhosis. Clonorchis sinensis has been known to cause cholangiocarcinoma, and is still a major health problem in endemic areas. People in endemic areas are repeatedly infected with C. sinensis, as they continue to consume raw freshwater fish in spite of control activities and availability of a highly effective drug, praziquantel. Reservoir hosts such as cats, dogs, and pigs supply eggs continuously to the environment and act as a source of infection. The present study analyzed the data produced by the Korea-China collaborative project for helminthiasis control in China during 2001–2004 to find out effective chemotherapeutic control strategies with praziquantel in endemic areas and to evaluate their effects on the transmission of C. sinensis infection by repeated mass or selective treatment. The four-year control trial found that repeated treatment is essential to the effective reduction of prevalence and infection intensity in heavily endemic areas. Mass chemotherapy is more effective than selective treatment, and more repeated treatments produce better outcomes in clonorchiasis control. Health education to change the habit of consuming raw or undercooked fish is an important and practical measure to prevent and reduce human infections in endemic areas. Together with chemotherapy, health education could be highly effective and produce sustainable effects in clonorchiasis control. Treatment of reservoirs, if applicable, will contribute to reduce the source of infection
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