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1.
Valenzuela R.A. Landron O. Jacobs D.L. 《Vehicular Technology, IEEE Transactions on》1997,46(1):203-212
We explore techniques for the measurement of local mean signal strength at 900 MHz and 2 GHz. In particular, we characterize the impact of transmitter and receiver antenna rotation on the estimated local mean. Then, we explore the collection of high resolution data while moving along a linear trajectory and using linear averaging techniques to estimate the local mean. With this information, the best measurement techniques can be chosen depending on the required speed versus accuracy tradeoff. Finally, we use a ray tracing propagation model to evaluate different methods of calculating the local mean signal strength for indoor environments 相似文献
2.
BACKGROUND: It is not clear if old age is a risk factor for adverse drug reactions. AIM: To study the incidence of adverse drug reactions and the effect of age in patients admitted to an Internal Medicine Service in an university hospital. PATIENTS AND METHODS: Two hundred one patients, hospitalized at the Clinical Hospital of the Catholic University, were studied. These patients were followed using a prospective pharmacological surveillance method. For statistical purposes, patients aged 65 years old or older were compared with those younger than 65 years old. RESULTS: Patients over 65 years old had a 33% incidence of adverse drug reactions, mainly involving cardiovascular system and provoking metabolic disturbances. Younger subjects had a 24% incidence of adverse drug reactions, mainly involving the gastrointestinal system and the skin. Sixteen percent of adverse drug reactions were classified as severe and there was a direct relationship between its frequency and the number of drugs prescribed, the hospitalization length and the presence of renal failure. Younger patients with adverse drug reactions had lower serum albumin levels than those without adverse reactions. This relationship was not observed in older patients. CONCLUSIONS: The frequency of adverse drug reactions in hospitalized patients, is related to the number of drugs prescribed and the length of hospitalization. 相似文献
3.
4.
Gnauck A.H. Linke R.A. Kasper B.L. Pollock K.J. Reichmann K.C. Valenzuela R. Alferness R.C. 《Electronics letters》1987,23(6):286-287
We report coherent lightwave transmission at a data rate of 2Gbit/s over 170 km of optical fibre. Phase modulation is employed, and a bit error rate lower than 10-9 is achieved. The receiver sensitivity of ?39.0 dBm 10-9 BER) is an improvement of 2.4 dB over the best previously published direct-detection result for non-return-to-zero transmission. 相似文献
5.
It is well known that many industrial manipulators use an embedded linear proportional‐integral (PI) joint velocity controller to guarantee motion control through proper velocity commands. However, although this control scheme has been very successful in practice, not much attention has been paid to designing new PI velocity control structures. The problem of analyzing a saturated PI velocity joint velocity controller is addressed in this paper. By using the theory of singularly perturbed systems, the closed‐loop system is studied. The robot dynamics assumed in this paper take into account bounded time–varying disturbances which may include the friction at the joints. An experimental study in a planar two degrees‐of‐freedom direct‐drive robot is also presented, confirming the advantage of the new saturated PI joint velocity controller. 相似文献
6.
Pan Xue Cristian Valenzuela Shaoshuai Ma Xuan Zhang Jiazhe Ma Yuanhao Chen Xinhua Xu Ling Wang 《Advanced functional materials》2023,33(24):2214867
Sophisticated sensing and actuation capabilities of many living organisms in nature have inspired scientists to develop biomimetic somatosensory soft robots. Herein, the design and fabrication of homogeneous and highly conductive hydrogels for bioinspired somatosensory soft actuators are reported. The conductive hydrogels are synthesized by in situ copolymerization of conductive surface-functionalized MXene/Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) ink with thermoresponsive poly(N-isopropylacrylamide) hydrogels. The resulting hydrogels are found to exhibit high conductivity (11.76 S m−1), strain sensitivity (GF of 9.93), broad working strain range (≈560% strain), and high stability after over 300 loading–unloading cycles at 100% strain. Importantly, shape-programmable somatosensory hydrogel actuators with rapid response, light-driven remote control, and self-sensing capability are developed by chemically integrating the conductive hydrogels with a structurally colored polymer. As the proof-of-concept illustration, structurally colored hydrogel actuators are applied for devising light-driven programmable shape-morphing of an artificial octopus, an artificial fish, and a soft gripper that can simultaneously monitor their own motions via real-time resistance variation. This work is expected to offer new insights into the design of advanced somatosensory materials with self-sensing and actuation capabilities, and pave an avenue for the development of soft-matter-based self-regulatory intelligence via built-in feedback control that is of paramount significance for intelligent soft robotics and automated machines. 相似文献
7.
S. Neupane G. Kaganas R. Valenzuela L. Kumari X. W. Wang W. Z. Li 《Journal of Materials Science》2011,46(14):4803-4811
We report the synthesis of ruthenium dioxide (RuO2) nanostructures by thermal evaporation of RuO2 powder. RuO2 nanostructures of different shapes were synthesized at various concentration, flow rate, and pressure of oxygen. At a constant pressure of 3 torr of flowing oxygen, polygonal prism-like RuO2 nanorods with flat tips were grown at an O2 flow rate of 100 sccm; club-shaped nanorods with obelisk tip were formed at 300 and 600 sccm, and hollow rods with square tip were formed at 1800 sccm. A mixture of O2 and Ar at a total flow rate of 600 sccm led to the formation of short club-shaped nanorods indicating the suppression effect of Ar on the growth of nanorods. The pressure also had a significant effect on the formation of RuO2 nanostructures, at a fixed flow rate of 600 sccm of O2, a pressure of 3 torr resulted in the growth of club-shaped RuO2 nanorods, while high pressures of 380 and 760 torr resulted in the formation of both linear club-shaped and pine tree-like hierarchical RuO2 nanorods. X-ray diffraction and transmission electron microscopy analysis indicated the formation of tetragonal phase of RuO2 with high crystallinity. A density functional calculation on RuO2, RuO3, and RuO4 was performed to help to explain the experimental results. 相似文献
8.
G. Tiburcio Munive M.A. Encinas Romero A. Valenzuela Soto V. Vázquez Vázquez J. H. Coronado López 《Canadian Metallurgical Quarterly》2018,57(3):312-318
A novel process was used to extract manganese from minerals that are refractory to cyanidation and ammonium thiosulphate. These minerals, known as mangano-argentiferous compounds, are principally composed of manganese, silver, and iron and exhibit low recovery. The mineral of interest was obtained from the leaching tails procured in Monte del Favor, Hostotipaquillo, Jalisco, Mexico. The tailings were characterised by X-ray powder diffraction (XRD), atomic absorption, and energy dispersive X-ray spectroscopy (EDS) microanalysis. After mineralogical characterisation, the tailings were screened through a mesh (mesh number 100, 0.147?mm); later, they were subjected to a reductive leaching process, where the solid–liquid ratio was varied from 2:1 to 10:1. A 5:1 ratio yielded the highest manganese content. With sulphuric acid and sodium sulphite as the reducing agents, 96.05% of Mn could be extracted during the first 3?h, with a head grade of 3.58% and an acid consumption of 49.31?kg/t. The sulphite consumption was found to be 9.81?kg/t. 相似文献
9.
Salmonellosis on the dairy continues to have a significant effect on animal health and productivity and in the United States. Additionally, Salmonella enterica ssp. enterica causes an estimated 1.2 million cases of human illness annually. Contributing to the morbidity and mortality in both human and domestic animal species is emergence of antimicrobial resistance by Salmonella species and increased incidence of multidrug-resistant isolates. This study describes serotype distribution and the antimicrobial resistance patterns for various Salmonella serotypes isolated from bovine samples submitted to the Wisconsin Veterinary Diagnostic Laboratory (WVDL) over the past 10 yr. Salmonella serotyping and antimicrobial susceptibility testing data were obtained from the laboratory information management system at WVDL. Data from accessions were limited to bovine samples submitted to the WVDL between January 2006 and June 2015 and those that had both a definitive serotype and complete results for antimicrobial susceptibility testing. A total of 4,976 isolates were identified. Salmonella enterica ser. Dublin was the most prevalent serotype identified among bovine samples submitted to the WVDL, accounting for a total of 1,153 isolates (23% of total isolates) over the study period. Along with Dublin, Salmonella enterica ser. Cerro (795, 16%), Newport (720, 14%), Montevideo (421, 8%), Kentucky (419, 8%), and Typhimurium (202, 4%) comprised the top 6 most commonly isolated serotypes during that time. Overall, resistance of bovine Salmonella isolates in the study population remained stable, although decreases in resistance were noted for gentamicin, neomycin, and trimethoprim sulfamethoxazole during the study period. All isolates remained susceptible to enrofloxacin. These data show that antimicrobial susceptibility for bovine Salmonella has changed in the population served by WVDL in the past 10 yr. This information is important for understanding Salmonella disease ecology in Wisconsin. Our findings are also relevant for animal and public health by improving informed antimicrobial use, new drug development, and regulation of their use in food animals. 相似文献
10.
The objective of our study was to analyse the fluctuation of cardiotocographic scores during labor in fetal growth retardation (FGR). The study took place at the University hospital "Principe de Asturias", Alcalá de Henares, Madrid, Spain. 170 at term FGR fetuses and 170 at term fetuses without FGR as control group were compared using modified Fischer scores, which were blindly performed at 3, 5 and 10 cm of cervical dilatation. As results we found out that the mean value of the Fischer score was significantly lower in FGR at 3 cm of cervical dilatation (8.1 +/- 1 vs 8.7 +/- 0.6), as well as at 5 cm (7.6 +/- 0.9 vs 8.1 +/- 0.7) and at 10 cm (6.7 +/- 0.8 vs 7.4 +/- 0.8). Poor prognosis cardiotocograms were also more common in FGR than in the control group in the three cut-offs points studied (7.5% vs 0.6% at 3 cm, 9.8 vs 1.8 at 5 cm and 37.9 vs 11.6 at complete cervical dilatation). The afore mentioned differences were more remarkable as labor advanced. Conclusions are that poor fetal heart rate recordings were detected in FGR at the beginning of labor when compared with control group fetuses and the differences between both groups increased while the labor prolonging. 相似文献