59 research outputs found
Oscillation behavior of second order nonlinear neutral differential equations with deviating arguments
Oscillation criteria are established for second order nonlinear neutral differential equations with deviating arguments of the form where and . Our results improve and extend some known results in the literature. Some illustrating examples are also provided to show the importance of our results
Use of Crumb Rubber Modified Binders and Asphalt Mixtures in Public Works Authority Road Projects - State of Qatar
This paper illustrates the approach adopted by the Public Works Authority (Ashghal)
of the State of Qatar for the widespread implementation in road projects of paving
technologies related to the use of crumb rubber modified binders (CRMBs). Such an
approach has entailed the monitoring of a full-scale preliminary trial, the definition of a
prequalification system for crumb rubber and CRMB producers, and the development
of mix design and quality control guidelines applicable to CRMB asphalt mixtures.
Experimental results obtained in the preparatory phases of work and during the approval
process of materials and mixtures are critically presented
Test Procedures for Advanced Characterization of Bituminous Binders Employed for Pavement Construction in Public Works Authority Road Projects - State of Qatar
This paper illustrates the approach adopted by the Public Works Authority (Ashghal)
of the State of Qatar for the advanced chemical and rheological characterization of
bituminous binders (both neat and modified). The ultimate objective of testing is to
create a database of employed binders, which may be meaningful for the optimization of
the selection of materials and for the consequent enhancement of pavement performance.
This paper provides an illustration of employed testing procedure and briefly discusses
typical experimental results
Engineering models for the design of long-lasting, sustainable, cost-efficient and climate-responsive pavements for Ashghal road projects in the State of Qatar
The planning, design, construction and management of modern transportation infrastructures is
based on the use of continuously updated methodologies that consider, among others, the
concept of sustainability. In such a context, for the specific case of road pavements, it is of crucial
importance to carry out quantitative analyses based on the use of optimized engineering models.
These models explicitly consider environment-pavement interactions, environmental impacts
generated by all the components involved in the supply chain, and financial flows associated to
pavement construction and maintenance. Such an approach is being adopted by the Public Works
Authority (Ashghal) of the State of Qatar, that is developing and implementing models tailored
for its infrastructure projects and local environmental conditions. This paper provides an
overview of some of the employed models and methodologies that are based on the physics of
pavement structures and on the assessment of environmental and economic indicators. It is
shown that such an approach leads to significant improvements to current practice and to the
enhanced use of recycled materials, while still guaranteeing required pavement performance
Improved results for testing the oscillation of functional differential equations with multiple delays
In this article, we test whether solutions of second-order delay functional differential equations oscillate. The considered equation is a general case of several important equations, such as the linear, half-linear, and Emden-Fowler equations. We can construct strict criteria by inferring new qualities from the positive solutions to the problem under study. Furthermore, we can incrementally enhance these characteristics. We can use the criteria more than once if they are unsuccessful the first time thanks to their iterative nature. Sharp criteria were obtained with only one condition that guarantees the oscillation of the equation in the canonical and noncanonical forms. Our oscillation results effectively extend, complete, and simplify several related ones in the literature. An example was given to show the significance of the main results
Effects of Sub-lethal Lead Nitrate and Copper Sulfate Concentrations on Hematological Parameters During Long-term Exposure in Nile tilapia (Oreochromis niloticus)
437-441Nile tilapia (Oreochromis niloticus) weighing 51.66 ± 2.42 g were exposed to 0%, 20%, 40%, and 60% of LC50 to either lead nitrate (Pb(NO3)2) or copper sulfate (CuSO4) for 30 days. The Pb(NO3)2 and CuSO4 concentrations employed in the treatments of this study were 8.8, 17.6, and 26.4 mg/L and 2.57, 5.14, and 7.71 mg/l, respectively, and multiple hematological variables were evaluated. The red blood cell (RBC) count for the control group was 2.41 ± 0.13 while those of the treatment groups exposed to 8.8, 17.6, and 26.4 mg/L of Pb(NO3)2 were 2.21 ± 0.10, 1.94 ± 0.16, and 1.36 ± 0.10 × 106/µl, respectively, at the end of the study. Similarly, the hemoglobin (Hb), hematocrit (Hct), mean cell hemoglobin (MCH), mean cell hemoglobin concentration (MCHC), and platelet (PLT( levels significantly decreased as the Pb(NO3)2 concentration increased (p 4, showed decrease in the levels of RBC, Hb, Hct, WBC, and PLT when the concentration of CuSO4 increased, while the MCHC, MCH, and MCV levels significantly increased
Anatomical patterns of recurrence following biochemical relapse after post‐prostatectomy salvage radiation therapy: a multi‐institutional study
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138303/1/bju13792.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138303/2/bju13792_am.pd
Association of stem cell factor gene expression with severity and atopic state in patients with bronchial asthma
Burnout among surgeons before and during the SARS-CoV-2 pandemic: an international survey
Background: SARS-CoV-2 pandemic has had many significant impacts within the surgical realm, and surgeons have been obligated to reconsider almost every aspect of daily clinical practice. Methods: This is a cross-sectional study reported in compliance with the CHERRIES guidelines and conducted through an online platform from June 14th to July 15th, 2020. The primary outcome was the burden of burnout during the pandemic indicated by the validated Shirom-Melamed Burnout Measure. Results: Nine hundred fifty-four surgeons completed the survey. The median length of practice was 10 years; 78.2% included were male with a median age of 37 years old, 39.5% were consultants, 68.9% were general surgeons, and 55.7% were affiliated with an academic institution. Overall, there was a significant increase in the mean burnout score during the pandemic; longer years of practice and older age were significantly associated with less burnout. There were significant reductions in the median number of outpatient visits, operated cases, on-call hours, emergency visits, and research work, so, 48.2% of respondents felt that the training resources were insufficient. The majority (81.3%) of respondents reported that their hospitals were included in the management of COVID-19, 66.5% felt their roles had been minimized; 41% were asked to assist in non-surgical medical practices, and 37.6% of respondents were included in COVID-19 management. Conclusions: There was a significant burnout among trainees. Almost all aspects of clinical and research activities were affected with a significant reduction in the volume of research, outpatient clinic visits, surgical procedures, on-call hours, and emergency cases hindering the training. Trial registration: The study was registered on clicaltrials.gov "NCT04433286" on 16/06/2020
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