739 research outputs found
Benthic macroinvertebrate communities of diverse gravel pit ponds of the Southeast Regional Park of Madrid
Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, Departamento de Zoología y Antropología Física, leída el 01/04/2011.Resumen en español.Depto. de Genética, Fisiología y MicrobiologíaFac. de Ciencias BiológicasTRUEProQuestpu
Seismic assessment of curved bridges using modal pushover analysis
The assessment of existing bridge structures against earthquake threat has become a major issue lately, motivated by the maturity of seismic design of new structures, on one side, and by the recognition of the inadequate level of seismic protection, the aging and the constant need of maintenance of the existing ones, on the other. While nonlinear time history analysis (NL-THA) is the most rigorous procedure to compute seismic demands, many seismic-prone countries, such as United States, New Zealand, Japan and Italy, have recently released standards for the assessment of buildings, all of which include the use of the non-linear static analysis procedure (NSP), the so-called pushover. Recently Chopra and Goel (2002) proposed the modal pushover analysis (MPA) procedure that considers the effect of higher modes on the behavior of buildings.
This research investigation is intended to evaluate the accuracy of the modal pushover analysis (MPA) procedure in estimating seismic demands for curved bridges after proposing some modifications that would render the MPA procedure applicable for bridges. For verification purpose, the nonlinear time history analysis (NL-THA) is also performed in order to quantify the accuracy of MPA. Three bridges were analyzed using both the MPA and NL-THA in addition to the standard pushover analysis (SPA). Maximum Demand displacements, total base shear and plastic rotations obtained from SPA and MPA are compared with the corresponding values resulting from the NL-THA. Comparison shows a good agreement between MPA and NL-THA results and MPA is deemed to be accurate enough for practical use. Furthermore, to evaluate the applicability of the MPA method for a wide range of bridges, a parametric study using both the MPA and NL-THA is performed. Results from the MPA for demand displacement and base shear are compared with results from the NL-THA. Also, the influence of different parameters on the behavior of curved bridges is studied. Parameters included the girder cross section (steel I vs. steel BOX), span length, number of spans, radius of curvature, and pier height. Pier height is found to have the most significant effect on bridge behavior as well as span length, while radius of curvature is found to have less influence on the behavior of curved bridges
Qualitative insights into the voltage stability problem
This work investigates some of the bus indicators for the problem of voltage stability. The purpose is to learn more about the behavior and to observe the factors that cause mis-ranking in estimating the stability margin. Three indicators are examined, the L-index, the coupled-port method, and the P-index. it found that the L-index does not have a reliable alarm level, and when flagged with an alarm used for the P-index, it shows a large variation of the estimation accuracy across systems. Also, the coupled single-port method is a reformulated L-index method with no novelty on estimation, the novelty is only in the presentation. Finally, the P-index is examined and found to be more reliable if it coincides with a maximum P-index and greater participation in the collapse mode. This is tested on benchmark systems; the results indicate that this approach leads to a better estimation in many cases
Benthic macroinvertebrate communities of diverse gravel pit ponds of the Southeast Regional Park of Madrid
Resumen en español
Obstetric complications and neonatal outcome of grandmultiparity: A comparative study
Background: The aim of the current study was to determine the prevalence of grand multiparity and the associated risks factors. Methods: Four hundred thirty grand mutliparas (parity 5 or more) were compared with multiparous population (parity 2-4) with regard to maternal age, gestational age, mode of delivery, fetal and maternal outcomes and inter-current medical and obstetrical problems.Results: There were significant association between grand multiparity and adverse pregnancy outcomes such as cesarean delivery (OR=2.699, CI=2.072-3.515, P <0.001), fetal macrosomia (OR=1.675; 95% CI=1.004-2.796, P = 0.048), diabetes mellitus (OR=1.634, 95%CI=1.076-2.481, P = 0.021), and pregnancy induced hypertension (OR=1.838, 95% CI=1.054-3.204, P = 0.032). No significant associations were seen in placenta abruption, placenta previa, preterm labor, postpartum hemorrhage and the frequency of admission to neonatal intensive care unit. No prenatal or maternal mortality was reported in this study.Conclusions: Grand multiparity remains a major obstetrics problem. It is associated with many medical and obstetrical complications. In communities where large family is desirable it is important to address the value of family planning and conduction of meticulous antenatal care
Evaluation of the quality of life in patients with coronary heart disease: using two measuring assessment tools
Background: Coronary heart diseases (CHD) are considered to be as a major cause of morbidity and mortality worldwide. Health-Related Quality of Life (HRQL) test and assessment is considered as a major an important measuring tool of the disease effects results and other variables related to the patient’s life.Objectives: The purpose of this observational study is to assess and compare the quality of life in patients with coronary heart disease.Materials and Methods: This study was conducted at Al-shaab Teaching Hospital, where 100 patients with definite diagnosis of CHD were responded. The data was collected using two quality of life assessment tools: the Seattle angina questionnaire (SAQ) (disease specific measuring tool) and the SF-36 questionnaire (generic measuring tool).Results: Based on the 1) SAQ, out of the 50 patients who were recruited, the patients physical functioning in terms of activities performed 58% said “not limited” and 42% said “limited” in case of chest pain 26% noted “much more often” while 10% “much less often” Based on the 2) SF-36, out of the 50 patients who were recruited, the patients physical functioning in terms of activates performed 26% said “no, not limited” and 74% said “limited”. 34% had felt full of life “all the time” while 10% “none of the time”.Conclusion: HRQL measurement gives health care providers an additional tool for the assessment of the impact of specific clinical decisions on the health status of patients. Of the SAQ and SF-36, the SAQ offers more reliable assessment of quality of life.Keywords: Coronary heart Disease, measuring assessment tool
An In-Vitro Assessment of Anti-Tumor Activity of Some Plant Extract and Natural Products, Using Potato Discs Bioassay Technique
Objectives: This study aimed to examine some plant extracts and natural products for anti-tumor activity.
Methodology: Potato disc bioassay was used to estimate anti-tumor activity of some plant extracts and natural products. Five plant extracts and natural products recommended in a questionnaire filled by local botanists in addition to an introduced fermented food “Manda Koso” were used in this study.
Study design: A questionnaire was designed and filled by 60 botanists looking for plant extracts and natural products having anti-cancer activity. In addition, computer surveys were conducted for gathering information on promising natural compounds act as anticancer agents. The potato disc bioassay was conducted using the Complete Randomized Design with three replicates. Each treatment in each replicate was represented by two Petri dishes contained five potato discs each. Petri dishes treated with sterilized water were used as control. Four separate experiments were carried out using TLC technique.
Results & Discussion: Results showed highly significant differences among treatments with respect to total number of tumors and inhibition average percentage (%). The inhibition average percentage (IAP) for the different products ranged between 80.95-100% for the different products and equal zero for the control. It was 100% for Manda Kosa and bees honey followed by 90.23% for olive oil. Other treatments showed moderate anti-tumor effect of 80.95% IAP.
Conclusions: Results concluded that Manda Koso, bees honey and olive oil have anti-tumor activity. Great association was found between anti-tumor activity obtained in this study and those published for anticancer activity of the promising material.
الملخص:
أجريت الدراسة بمعمل الاحياء الدقيقة بكلية الهندسة والتكنولوجيا بجامعة الجزيرة فى الفترة من 3 ابريل وحتى21 سبتمبر(2008) وذلك بغرض دراسة مقدرة بعض المستخلصات النباتية على تثبيط الاورام المستحثة باستخدام سلالة محلية من البكتيريا الزراعية Agrobacterium tumefaceins تسمى SDB0012”" وذلك باستخدام تقنية قرص البطاطس وتقنية الفصل الكروماتوجرافى للتعرف على الجزيئات الفعالة للمستخلصات الطبيعية المستخدمة فى هذه الدراسة. اوضحت النتائج فروقات معنوية عالية ما بين المستخلصات المستخدمة في العدد الكلي للاورام واحجامها. اعطي المستخلص اليابانى ماندا كوسو " Manda Koso" فعالية عالية على التثبيط الكلي للأورام المستحثة, تليها عينة محلية لعسل النحل ثم زيت الزيتون ثم زيت الحبة السوداء (الكمون) ثم زيت الثوم واقل نسبة رصدت في زيت الحلبة. أوصت الدراسة لاستخدام كل من ماندا كوسو, العسل و زيت الحبة السوداء كمثبطات نمو الاورام. اتضح من خلال هذه الدراسة فعالية استخدام تقنية اقراص البطاطس في تحديد مثبطات لنمو الاورام في كل من البطاطس والانسان وذلك من خلال تقارب النتائج بين هذا الاختبار في هذه التجربة و النتائج العالمية في هذه المستخلصات. هذا وقد اقترحت الدراسة إجراء استخدام تقنيات الفصل الكروماتوجرافى و كروماتوجرافيا الغاز GC و تقنية HPLC بالاضافة لتقنية الهجرة الكهربية electrophoresis gel لفصل البروتينات
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