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Search Results: 1 - 10 of 3226 matches for " Roberta;Nahas "
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Employing Two ‘Sandwich Delay’ Mechanisms to Enhance Predictability of Embedded Systems Which Use Time-Triggered Co-Operative Architectures  [PDF]
Mouaaz Nahas
Journal of Software Engineering and Applications (JSEA) , 2011, DOI: 10.4236/jsea.2011.47048
Abstract: In many real-time resource-constrained embedded systems, highly-predictable system behavior is a key design requirement. The “time-triggered co-operative” (TTC) scheduling algorithm provides a good match for a wide range of low-cost embedded applications. As a consequence of the resource, timing, and power constraints, the implementation of such algorithm is often far from trivial. Thus, basic implementation of TTC algorithm can result in excessive levels of task jitter which may jeopardize the predictability of many time-critical applications using this algorithm. This paper discusses the main sources of jitter in earlier TTC implementations and develops two alternative implementations – based on the employment of “sandwich delay” (SD) mechanisms – to reduce task jitter in TTC system significantly. In addition to jitter levels at task release times, we also assess the CPU, memory and power requirements involved in practical implementations of the proposed schedulers. The paper concludes that the TTC scheduler implementation using “multiple timer interrupt” (MTI) technique achieves better performance in terms of timing behavior and resource utilization as opposed to the other implementation which is based on a simple SD mechanism. Use of MTI technique is also found to provide a simple solution to “task overrun” problem which may degrade the performance of many TTC systems.
Basal cell carcinoma: an updated epidemiological and therapeutically profile of an urban population
Bariani Roberta Lopes,Nahas Fábio Xerfan,Barbosa Marcus Vinícius Jardini,Farah Andréia Bufoni
Acta Cirurgica Brasileira , 2006,
Abstract: PURPOSE: To describe the epidemiological profile of basal cell carcinoma patients at a private hospital in S o Paulo and to evaluate the treatment adopted. METHODS: A prospective study of 202 patients, on which 253 lesions were diagnosed for histopathological exam as basal cell carcinoma within the period of January 2001 to September 2003, in the Plastic Surgery Residency Program at the Hospital Jaraguá. The susceptibility factor of the host, the environment variables, the characteristics of the lesions and the efficacy of the treatment were examined. The data were statistically evaluated. RESULTS: The incidence of basal cell carcinoma was 126 cases per 100,000 patients in a period of 32 months (36 cases per 100,000 patients/year). The patients were evenly distributed in terms of sex: 48% male and 52% female. The greater incidence was in patients between the ages of 60 and 80 years and the average was 64 years. The survey revealed susceptibility factors such as white race and phototypes I and II in 95.5% of the patients. Exposition to ultraviolet radiation was reported by 77% of the patients and the most frequent location of tumors was on the face (71.2% of the cases). Actinic keratosis and a history of skin cancer were reported in 43.6% and in 25% of the cases, respectively. The adopted treatment was surgery in 99.4% of the cases and only one patient was treated with radiotherapy. Twenty lesions (8%) had incomplete excision.The recurrence rate was 2% (5 cases). There were no cases with metastasis or fatal outcome. CONCLUSIONS: The factors related to the development of basal cell cancer which were significantly present in the population surveyed were: older age, white individuals, phototypes I and II, presence of actinic keratosis, previous history of non-melanoma skin cancer and exposure to ultra-violet rays both in recreational and in occupational form.The surgical treatment employed was effective with a rate of incomplete excision and recurrence similar to those found in the literature.
50 GHz Spaced 4 × 40 Gbit/s WDM Transmission over 700 km Using 6 ps Bandlimited RZ Signals  [PDF]
Mousaab M. Nahas
Optics and Photonics Journal (OPJ) , 2011, DOI: 10.4236/opj.2011.13023
Abstract: In this paper, we present 50 GHz spaced 4 ×40 Gbit/s WDM transmission over 700 km using SMF-based Effective Area Enlarged Positive Dispersion Fiber in a recirculating loop. The paper uses bandlimited RZ signals and shows that transmission distance of 700 km can be achieved with BER ≤ 10-9 using 6 ps pulsewidth for each data signal. To attain this, optical filters with sharp transmission characteristics are used in both transmitter and receiver. The results demonstrated in this paper are based on simulation, and the author believes the propagation distance reached in the paper is the longest distance achieved for such system.
Basal cell carcinoma: an updated epidemiological and therapeutically profile of an urban population
Bariani, Roberta Lopes;Nahas, Fábio Xerfan;Barbosa, Marcus Vinícius Jardini;Farah, Andréia Bufoni;Ferreira, Lydia Masako;
Acta Cirurgica Brasileira , 2006, DOI: 10.1590/S0102-86502006000200003
Abstract: purpose: to describe the epidemiological profile of basal cell carcinoma patients at a private hospital in s?o paulo and to evaluate the treatment adopted. methods: a prospective study of 202 patients, on which 253 lesions were diagnosed for histopathological exam as basal cell carcinoma within the period of january 2001 to september 2003, in the plastic surgery residency program at the hospital jaraguá. the susceptibility factor of the host, the environment variables, the characteristics of the lesions and the efficacy of the treatment were examined. the data were statistically evaluated. results: the incidence of basal cell carcinoma was 126 cases per 100,000 patients in a period of 32 months (36 cases per 100,000 patients/year). the patients were evenly distributed in terms of sex: 48% male and 52% female. the greater incidence was in patients between the ages of 60 and 80 years and the average was 64 years. the survey revealed susceptibility factors such as white race and phototypes i and ii in 95.5% of the patients. exposition to ultraviolet radiation was reported by 77% of the patients and the most frequent location of tumors was on the face (71.2% of the cases). actinic keratosis and a history of skin cancer were reported in 43.6% and in 25% of the cases, respectively. the adopted treatment was surgery in 99.4% of the cases and only one patient was treated with radiotherapy. twenty lesions (8%) had incomplete excision.the recurrence rate was 2% (5 cases). there were no cases with metastasis or fatal outcome. conclusions: the factors related to the development of basal cell cancer which were significantly present in the population surveyed were: older age, white individuals, phototypes i and ii, presence of actinic keratosis, previous history of non-melanoma skin cancer and exposure to ultra-violet rays both in recreational and in occupational form.the surgical treatment employed was effective with a rate of incomplete excision and recurrence similar to those
Safety Measurements of Electromagnetic Fields Radiated from Mobile Base Stations in the Western Region of Saudi Arabia  [PDF]
Mouaaz Nahas, Mohammed T. Simsim
Wireless Engineering and Technology (WET) , 2011, DOI: 10.4236/wet.2011.24030
Abstract: Over the last decade, detrimental effects of human exposure to electromagnetic radiations have received widespread attention. Communications and Information Technology Commission (CITC) in Saudi Arabia has set guidelines and launched a national project—in collaboration with academic and research institutions—to perform measurements of the “electromagnetic fields” (EMFs) radiated from base stations of the mobile phone network. In keeping with its mission to address problems of the local community, Electrical Engineering (EE) department at Umm Al-Qura University (UQU) has been commissioned to conduct this project in the western region of Saudi Arabia. The project is concerned with measuring the strength of EMFs around base stations to locate the Maximum Peak Point (MPP). The aim of measurements is to ensure the site compliance with the CITC guidelines for human exposure to Radiofrequency (RF). This paper discusses possible health consequences caused by human exposure to RF radiations. Furthermore, it sum- marizes the results from 20 selective base stations located in Makkah, Madinah, Jeddah, Taif and Yanbu. The results show that EMF levels at all surveyed sites are far below the National Guidelines for public exposure to RF and that the MPPs are found within the distance range suggested in the CITC guidelines. The paper concludes by providing some useful comments and recommendations for RF sites surveyors.
Microrganismos do solo produtores de fosfatases em diferentes sistemas agrícolas
Nahas, Ely;
Bragantia , 2002, DOI: 10.1590/S0006-87052002000300008
Abstract: considering that one way for providing available phosphate to plants is by the microbial activity for the mineralization of organic phosphorus, the influence of plants (brachiaria ruziziensis, cajanus cajan and control), fertilizers (superphosphate, rock phosphate and control) and liming (with and without lime) was evaluated in the microorganisms populations of the acid and alkaline phosphatase producers. among bacteria, 70,6% showed alkaline phosphatase activity and 58,2% acid phosphatase activity and among fungi, 64,3% and 84,7%, respectively. these numbers show that a significant population of microorganisms shows ability for organic phosphorus mineralization. restrictive effect of the c. cajan was observed on the bacteria and fungi producers of the alkaline and acid phosphatases whose numbers always were lower to those obtained with the b. ruziziensis or with the plots without cultivation. larger number of alkaline phosphatase bacterial producers was obtained in the treatments with superphosphate and control than that with rock phosphate. on the opposite, for fungi, a larger number was found in the plots with no fertilizer compared to the ones with fertilizer. the population of fungi having acid phosphatase activity decreased in the limed plots whereas the bacterial population increased. finally, the alkaline phosphatase bacterial producers showed higher enzymatic activity than those of the fungi.
Microrganismos do solo produtores de fosfatases em diferentes sistemas agrícolas
Nahas Ely
Bragantia , 2002,
Abstract: Considerando-se que uma forma de prover fosfato disponível para as plantas é através da atividade mineralizadora microbiana do fósforo organico, avaliou-se a influência da planta (braquiária, guandu e sem planta), dos fertilizantes (superfosfato simples, fosfato de rocha e sem adubo) e da calagem (com e sem calcário) nas popula es de microrganismos produtores de fosfatases ácida e alcalina. Do total de bactérias, 70,6% apresentaram atividade de fosfatase alcalina e 58,2% de fosfatase ácida e dos fungos, 64,3% e 84,7% respectivamente. Esses dados mostram número significativo de microrganismos com habilidade de mineraliza o do fósforo organico. Observou-se efeito restritivo do guandu sobre as bactérias e fungos produtores de fosfatases alcalina e ácida, cujos números foram sempre inferiores aos obtidos com a cultura de braquiária ou com as parcelas sem cultivo. Maior número de bactérias produtoras de fosfatase alcalina foi obtido nos tratamentos com superfosfato e controle do que com fosfato de rocha. Ao contrário, para os fungos, encontrou-se maior número nas parcelas n o fertilizadas que as adubadas com fosfato. O número de fungos com atividade de fosfatase ácida diminuiu por efeito da calagem, enquanto o das bactérias aumentou. Finalmente, o número de bactérias produtoras de fosfatase alcalina superou o de fungos.
The Frontiers in Brain Imaging and Neuromodulation: A New Challenge
Ziad Nahas
Frontiers in Psychiatry , 2010, DOI: 10.3389/fpsyt.2010.00025
Abstract:
A decay property of solutions to the k-generalized KdV equation
Joules Nahas
Mathematics , 2010,
Abstract: We use a Leibnitz rule type inequality for fractional derivatives to prove conditions under which a solution $u(x,t)$ of the k-generalized KdV equation is in the space $L^2(|x|^{2s}\,dx)$ for $s \in \mathbb R_{+}$.
Scattering of Wave Maps from $\mathbb R^{2+1}$ to general targets
Joules Nahas
Mathematics , 2010,
Abstract: We show that smooth, radially symmetric wave maps $U$ from $\mathbb R^{2+1}$ to a compact target manifold $N$, where $\partial_r U$ and $\partial_t U$ have compact support for any fixed time, scatter. The result will follow from the work of Christodoulou and Tahvildar-Zadeh, and Struwe, upon proving that for $\lambda' \in (0,1)$, energy does not concentrate in the set $$K_{5/8T,7/8T}^{\lambda'} = {(x,t) \in \mathbb R^{2+1} | {5pt} |x| \leq \lambda' t, t \in [(5/8)T,(7/8)T]}.$$
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