446 research outputs found
Real time lane detection for autonomous vehicles
An increasing safety and reducing road
accidents, thereby saving lives are one of great interest
in the context of Advanced Driver Assistance Systems.
Apparently, among the complex and challenging tasks
of future road vehicles is road lane detection or road
boundaries detection. It is based on lane detection
(which includes the localization of the road, the
determination of the relative position between vehicle
and road, and the analysis of the vehicle’s heading
direction). One of the principal approaches to detect
road boundaries and lanes using vision system on the
vehicle. However, lane detection is a difficult problem
because of the varying road conditions that one can
encounter while driving. In this paper, a vision-based
lane detection approach capable of reaching real time
operation with robustness to lighting change and
shadows is presented. The system acquires the front
view using a camera mounted on the vehicle then
applying few processes in order to detect the lanes.
Using a pair of hyperbolas which are fitting to the
edges of the lane, those lanes are extracted using
Hough transform. The proposed lane detection system
can be applied on both painted and unpainted road as
well as curved and straight road in different weather
conditions. This approach was tested and the
experimental results show that the proposed scheme
was robust and fast enough for real time requirements.
Eventually, a critical overview of the methods were
discussed, their potential for future deployment were
assis
Genetic diversity of hepatitis E virus (HEV) in imported and domestic camels in Saudi Arabia
Camels gained attention since the discovery of MERS-CoV as intermediary hosts for potentially epidemic zoonotic viruses. DcHEV is a novel zoonotic pathogen associated with camel contact. This study aimed to genetically characterize DcHEV in domestic and imported camels in Saudi Arabia. DcHEV was detected by RT-PCR in serum samples, PCR-positive samples were subjected to sequencing and phylogenetic analyses. DcHEV was detected in 1.77% of samples with higher positivity in domestic DCs. All positive imported dromedaries were from Sudan with age declining prevalence. Domestic DcHEV sequences clustered with sequences from Kenya, Somalia, and UAE while imported sequences clustered with one DcHEV isolate from UAE and both sequences clustered away from isolates reported from Pakistan. Full-genome sequences showed 24 amino acid difference with reference sequences. Our results confirm the detection of DcHEV in domestic and imported DCs. Further investigations are needed in human and camel populations to identify DcHEV potential zoonosis threat
Re-infection with a different SARS-CoV-2 clade and prolonged viral shedding in a hematopoietic stem cell transplantation patient
Immunocompromised patients who have a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection pose many clinical and public health challenges. We describe the case of a hematopoietic stem cell transplantation patient with lymphoma who had a protracted illness requiring three consecutive hospital admissions. Whole genome sequencing confirmed two different SARS-CoV-2 clades. Clinical management issues and the unanswered questions arising from this case are discussed
COVID-19 vaccine hesitancy : mobile education initiatives to improve vaccination uptake among healthcare workers
Vaccine hesitancy is a global threat to public health contributed by misinformation
and lay beliefs about diseases and health. Our study aimed to assess preparedness
and intent to receive COVID-19 vaccine among healthcare workers in a single
institution in northwest Malaysia and assess the feasibility and efficacy of our
mobile education programme to overcome vaccine hesitancy among healthcare
workers. Our initial survey among 1,616 respondents found that 25.3% of
healthcare workers either refused or were hesitant towards COVID-19 vaccination;
238 respondents (58.2%) of which with no absolute clinical contraindication.
Our multifaceted mobile education programme involved: (i) series of continuous
medical education (CMEs) to 72 elected liaison officers, (ii) small scale briefing
session to individual unit and/or department upon request, and (iii) a one-to-one
counselling session upon request. The programme took the course of over four
weeks prior to the actual vaccination drive. Re-assessment of intent to receive
COVID-19 vaccine found a significant reduction of healthcare workers refusing
COVID-19 vaccination without absolute contraindication (25.3% vs. 2.8%). The
most common reasons cited among those who were still hesitant were due to
pregnancy (non-first trimester) and planning to conceive in the near future. Our
study demonstrated the efficacy of physical interaction and teaching session to
allow rapid communication and gives better understanding, particularly when
dealing with myths, misinformation and misconception related to COVID-19
vaccine
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Results of the MAJORANA DEMONSTRATOR's Search for Double-Beta Decay of 76Ge to Excited States of 76Se
The MAJORANA DEMONSTRATOR is searching for double-beta decay of 76Ge to excited states (E.S.) in 76Se using a modular array of high purity Germanium detectors. 76Ge can decay into three E.S.s of 76Se. The E.S. decays have a clear event signature consisting of a ββ-decay with the prompt emission of one or two γ-rays, resulting in with high probability in a multi-site event. The granularity of the DEMONSTRATOR detector array enables powerful discrimination of this event signature from backgrounds. Using 21.3 kg-y of isotopic exposure, the DEMONSTRATOR has set world leading limits for each E.S. decay, with 90% CL lower half-life limits in the range of (0.56 2.1) ⋅ 1024 y. In particular, for the 2v transition to the first 0+ E.S. of 76Se, a lower half-life limit of 0.68 ⋅ 1024 at 90% CL was achieved
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ADC Nonlinearity Correction for the Majorana Demonstrator
Imperfections in analog-to-digital conversion (ADC) cannot be ignored when signal digitization requirements demand both wide dynamic range and high resolution, as is the case for the Majorana Demonstrator 76Ge neutrinoless double-beta decay search. Enabling the experiment's high-resolution spectral analysis and efficient pulse shape discrimination required careful measurement and correction of ADC nonlinearities. A simple measurement protocol was developed that did not require sophisticated equipment or lengthy data-taking campaigns. A slope-dependent hysteresis was observed and characterized. A correction applied to digitized waveforms prior to signal processing reduced the differential and integral nonlinearities by an order of magnitude, eliminating these as dominant contributions to the systematic energy uncertainty at the double-beta decay Q value
The effect of intumescent mat on post-fire performance of carbon fibre reinforced composites
This study investigated the effect of intumescent mats (M1 and M2) with different compositions on the post-fire performance of carbon fibre reinforced composites. The sandwich structure was designed for composites where M1 (carbon fibre reinforced composite-M1) or M2 (carbon fibre reinforced composite-M2) mats were covered on the composite surface. A significant reduction in the peak heat release rate and total heat release was observed from the cone calorimetric data, and carbon fibre reinforced composite-M1 showed the lowest value of 148 kW/m2 and 29 MJ/m2 for peak heat release rate and total heat release, respectively. In addition, a minor influence on mechanical properties was observed due to the variation of composite thickness and resin volume in the composite. The post-fire properties of composite were characterised, and the M1 mat presented better retention of flexural strength and modulus. The feasibility of two-layer model was confirmed to predict the post-fire performance of composites and reduce the reliance on the large amounts of empirical data. © The Author(s) 2019
Suppression of LPS-induced inflammatory responses in macrophages infected with Leishmania
<p>Abstract</p> <p>Background</p> <p>Chronic inflammation activated by macrophage innate pathogen recognition receptors such as TLR4 can lead to a range of inflammatory diseases, including atherosclerosis, Crohn's disease, arthritis and cancer. Unlike many microbes, the kinetoplastid protozoan pathogen <it>Leishmania </it>has been shown to avoid and even actively suppress host inflammatory cytokine responses, such as LPS-induced IL-12 production. The nature and scope of <it>Leishmania</it>-mediated inflammatory cytokine suppression, however, is not well characterized. Advancing our knowledge of such microbe-mediated cytokine suppression may provide new avenues for therapeutic intervention in inflammatory disease.</p> <p>Methods</p> <p>We explored the kinetics of a range of cytokine and chemokine responses in primary murine macrophages stimulated with LPS in the presence versus absence of two clinically distinct species of <it>Leishmania </it>using sensitive multiplex cytokine analyses. To confirm that these effects were parasite-specific, we compared the effects of <it>Leishmania </it>uptake on LPS-induced cytokine expression with uptake of inert latex beads.</p> <p>Results</p> <p>Whilst <it>Leishmania </it>uptake alone did not induce significant levels of any cytokine analysed in this study, <it>Leishmania </it>uptake in the presence of LPS caused parasite-specific suppression of certain LPS-induced pro-inflammatory cytokines, including IL-12, IL-17 and IL-6. Interestingly, <it>L. amazonensis </it>was generally more suppressive than <it>L. major</it>. We also found that other LPS-induced proinflammatory cytokines, such as IL-1α, TNF-α and the chemokines MIP-1α and MCP-1 and also the anti-inflammatory cytokine IL-10, were augmented during <it>Leishmania </it>uptake, in a parasite-specific manner.</p> <p>Conclusions</p> <p>During uptake by macrophages, <it>Leishmania </it>evades the activation of a broad range of cytokines and chemokines. Further, in the presence of a strong inflammatory stimulus, <it>Leishmania </it>suppresses certain proinflammatory cytokine responses in a parasite-specific manner, however it augments the production of other proinflammatory cytokines. Our findings highlight the complexity of inflammatory cytokine signalling regulation in the context of the macrophage and <it>Leishmania </it>interaction and confirm the utility of the <it>Leishmania</it>/macrophage infection model as an experimental system for further studies of inflammatory regulation. Such studies may advance the development of therapies against inflammatory disease.</p
Commiphora molmol Modulates Glutamate-Nitric Oxide-cGMP and Nrf2/ARE/HO-1 Pathways and Attenuates Oxidative Stress and Hematological Alterations in Hyperammonemic Rats.
Hyperammonemia is a serious complication of liver disease and may lead to encephalopathy and death. This study investigated the effects of Commiphora molmol resin on oxidative stress, inflammation, and hematological alterations in ammonium chloride- (NH4Cl-) induced hyperammonemic rats, with an emphasis on the glutamate-NO-cGMP and Nrf2/ARE/HO-1 signaling pathways. Rats received NH4Cl and C. molmol for 8 weeks. NH4Cl-induced rats showed significant increase in blood ammonia, liver function markers, and tumor necrosis factor-alpha (TNF-α). Concurrent supplementation of C. molmol significantly decreased circulating ammonia, liver function markers, and TNF-α in hyperammonemic rats. C. molmol suppressed lipid peroxidation and nitric oxide and enhanced the antioxidant defenses in the liver, kidney, and cerebrum of hyperammonemic rats. C. molmol significantly upregulated Nrf2 and HO-1 and decreased glutamine and nitric oxide synthase, soluble guanylate cyclase, and Na+/K+-ATPase expression in the cerebrum of NH4Cl-induced hyperammonemic rats. Hyperammonemia was also associated with hematological and coagulation system alterations. These alterations were reversed by C. molmol. Our findings demonstrated that C. molmol attenuates ammonia-induced liver injury, oxidative stress, inflammation, and hematological alterations. This study points to the modulatory effect of C. molmol on glutamate-NO-cGMP and Nrf2/ARE/HO-1 pathways in hyperammonemia. Therefore, C. molmol might be a promising protective agent against hyperammonemia
Adaptive multi-polling scheduler for QoS support of video transmission in IEEE 802.11e WLANs
The 802.11E Task Group has been established to enhance quality of service (QoS) provision for time-bounded services in the current IEEE 802.11 medium access control protocol. The QoS is introduced throughout hybrid coordination function controlled channel access (HCCA) for the rigorous QoS provision. In HCCA, the station is allocated a fixed transmission opportunity (TXOP) based on its TSPEC parameters so that it is efficient for constant bit rate streams. However, as the profile of variable bit rate traffics is inconstant, they are liable to experience a higher delay especially in bursty traffic case. In this paper, we present a dynamic TXOP assignment algorithm called adaptive multi-polling TXOP scheduling algorithm (AMTXOP) for supporting the video traffics transmission over IEEE 802.11e wireless networks. This scheme invests a piggybacked information about the size of the subsequent video frames of the uplink streams to assist the hybrid coordinator accurately assign the TXOP according to actual change in the traffic profile. The proposed scheduler is powered by integrating multi-polling scheme to further reduce the delay and polling overhead. Extensive simulation experiments have been carried out to show the efficiency of the AMTXOP over the existing schemes in terms of the packet delay and the channel utilization
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