4 resultados para cluster-based routing protocol

em Biblioteca Digital da Produção Intelectual da Universidade de São Paulo


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This paper discusses some aspects related to Wireless Sensor Networks over the IEEE 802.15.4 standard, and proposes, for the very first time, a mesh network topology with geographic routing integrated to the open Freescale protocol (SMAC - Simple Medium Access Control). For this is proposed the SMAC routing protocol. Before this work the SMAC protocol was suitable to perform one hop communications only. However, with the developed mechanisms, it is possible to use multi-hop communication. Performance results from the implemented protocol are presented and analyzed in order to define important requirements for wireless sensor networks, such as robustness, self-healing property and low latency. (c) 2011 Elsevier Ltd. All rights reserved.

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The effects of estradiol benzoate (EB) and estradiol cypionate (EC) on induction of ovulation after a synchronized LH surge and on fertility of Bos indicus females submitted to timed AI (TAI) were evaluated. In Experiment 1, ovariectomized Nelore heifers were used to evaluate the effect of EB (n = 5) and EC (n = 5) on the circulating LH profile. The LH surge timing (19.6 and 50.5 h; P = 0.001), magnitude (20.5 and 9.4 ng/mL; P = 0.005), duration (8.6 and 16.5 h; P = 0.001), and area under the LH curve (158.6 and 339.4 ng/mL; P = 0.01) differed between the EB and EC treatments, respectively. In Experiment 2 (follicular responses; n = 60) and 3 (pregnancy per AI; P/AI; n = 953) suckled Bos indicus beef cows submitted to an estradiol/progesterone-based synchronization protocol were assigned to receive one of two treatments to induce synchronized ovulation: 1 mg of EB im 24 h after progesterone (P4) device removal or 1 mg of EC im at P4 device removal. There was no difference (P > 0.05) between EB and EC treatments on follicular responses (maximum diameter of the ovulatory follicle, 13.1 vs. 13.9 mm; interval from progesterone device removal to ovulation, 70.2 vs. 68.5 h; and ovulation rate, 77.8 vs. 82.8%, respectively). In addition, P/AI was similar (P < 0.22) between the cows treated with EB (57.5%; 277/482) and EC (61.8%; 291/471). In conclusion, despite pharmacologic differences, both esters of estradiol administered either at P4 device removal (EC) or 24 h later (EB) were effective in inducing an LH surge which resulted in synchronized ovulations and similar P/AI in suckled Bos indicus beef cows submitted to TAI. (C) 2012 Elsevier Inc. All rights reserved.

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The purpose of the present study was to verify whether a downhill running protocol was able to induce non-functional overreaching in > 75% of mice. Mice were divided into control (C), trained (TR) and overtrained (OTR) groups. Bodyweight and food intake were recorded weekly. The incremental load test (ILT) and the exhaustive test (ET) were used to measure performance before and after aerobic training and overtraining protocols. Although the bodyweight of the OTR group was lower than that of the C group at the end of Week 7, the food intake of the OTR group was higher than that of the C and TR groups at the end of Week 8. Evaluation of results from the ILT and ET revealed significant intra- and inter-group differences: whereas the parameters measured by both tests increased significantly in the TR group, they were significantly decreased in the OTR group. In conclusion, this new overtraining protocol based on downhill running sessions induced non-functional overreaching in 100% of mice.

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Background/purpose: Gallstones and cholelithiasis are being increasingly diagnosed in children owing to the widespread use of ultrasonography. The treatment of choice is cholecystectomy, and routine intraoperative cholangiography is recommended to explore the common bile duct. The objectives of this study were to describe our experience with the management of gallstone disease in childhood over the last 18 years and to propose an algorithm to guide the approach to cholelithiasis in children based on clinical and ultrasonographic findings. Methods: The data for this study were obtained by reviewing the records of all patients with gallstone disease treated between January 1994 and October 2011. The patients were divided into the following 5 groups based on their symptoms: group 1, asymptomatic; group 2, nonbiliary obstructive symptoms; group 3, acute cholecystitis symptoms; group 4, a history of biliary obstructive symptoms that were completely resolved by the time of surgery; and group 5, ongoing biliary obstructive symptoms. Patients were treated according to an algorithm based on their clinical, ultrasonographic, and endoscopic retrograde cholangiopancreatography (ERCP) findings. Results: A total of 223 patients were diagnosed with cholelithiasis, and comorbidities were present in 177 patients (79.3%). The most common comorbidities were hemolytic disorders in 139 patients (62.3%) and previous bariatric surgery in 16 (7.1%). Although symptoms were present in 134 patients (60.0%), cholecystectomy was performed for all patients with cholelithiasis, even if they were asymptomatic; the surgery was laparoscopic in 204 patients and open in 19. Fifty-six patients (25.1%) presented with complications as the first sign of cholelithiasis (eg, pancreatitis, choledocolithiasis, or acute calculous cholecystitis). Intraoperative cholangiography was indicated in 15 children, and it was positive in only 1 (0.4%) for whom ERCP was necessary to extract the stone after a laparoscopic cholecystectomy (LC). Preoperative ERCP was performed in 11 patients to extract the stones, and a hepaticojejunostomy was indicated in 2 patients. There were no injuries to the hepatic artery or common bile duct in our series. Conclusions: Based on our experience, we can propose an algorithm to guide the approach to cholelithiasis in the pediatric population. The final conclusion is that LC results in limited postoperative complications in children with gallstones. When a diagnosis of choledocolithiasis or dilation of the choledocus is made, ERCP is necessary if obstructive symptoms persist either before or after an LC. Intraoperative cholangiography and laparoscopic common bile duct exploration are not mandatory. Published by Elsevier Inc.