Computation of Running Averages

This brief presents and compares several recursive and nonrecursive techniques for the efficient computation of the running average of discrete signals. First of all, the standard recursive algorithm is considered and its long-term accuracy is assessed when the floating-point arithmetic is employed. A cheap refreshing strategy is proposed as a means of keeping the computed value close enough to the exact one. Then, two alternative nonrecursive algorithms, requiring only log₂N additions, are developed, which are as reliable and accurate as the direct implementation     

缺血性糖尿病下肢病变的膝下动脉成形术

目的探讨膝下动脉的球囊成形术在治疗糖尿病缺血性下肢病变中的价值。方法对５３例糖尿病合并缺血性下肢病变患者６４侧缺血性下肢进行膝下动脉Deep球囊扩张成形术。对比患者手术前后临床症状的改变及足部溃疡的变化。结果５３例患者共１１９支动脉分支接受PTA治疗，５０例患者的１０１个分支成功地开通，技术成功率为８４．９％，所有５０例患者的临床症状均明显缓解，足部溃疡均变小，无需截肢。结论膝下动脉的球囊成形术是治疗缺血性糖尿病下肢病变安全有效的微创手段     

Application of generalized phasors to eigenvector and natural response computation of LTI circuits

This paper focuses on the natural response computation of linear time-invariant (LTI) circuits, in those cases in which a closed-form solution, rather than numerical integration of the state-variable equations, is preferable. A computationally efficient procedure is presented to individually obtain the eigenvectors of matrix A, both for distinct and repeated eigenvalues. Instead of performing orthogonal matrix transformations, the proposed method relies on the solution of the nodal equations corresponding to a zero-input circuit in the generalized phasor domain. This allows propagation of natural modes to be computed by means of a simple procedure that closely resembles conventional ac analysis.     

Evolution of functional link networks

This paper addresses the genetic design of functional link networks (FLN). FLN are high-order perceptrons (HOP) without hidden units. Despite their linear nature, FLN can capture nonlinear input-output relationships, provided that they are fed with an adequate set of polynomial inputs, which are constructed out of the original input attributes. Given this set, it turns out to be very simple to train the network, as compared with a multilayer perceptron (MLP). However finding the optimal subset of units is a difficult problem because of its nongradient nature and the large number of available units, especially for high degrees. Some constructive growing methods have been proposed to address this issue, Here, we rely on the global search capabilities of a genetic algorithm to scan the space of subsets of polynomial units, which is plagued by a host of local minima. By contrast, the quadratic error function of each individual FLN has only one minimum, which makes fitness evaluation practically noiseless. We find that surprisingly simple FLN compare favorably with other more complex architectures derived by means of constructive and evolutionary algorithms on some UCI benchmark data sets. Moreover, our models are especially amenable to interpretation, due to an incremental approach that penalizes complex architectures and starts with a pool of single-attribute FLN     

Just how insoluble are monoterpenes?

Prior generalizations about the ecological roles of monoterpenes may be misleading if based on the presumed insolubility of monoterpenes in water. We determined the aqueous solubility of 31 biologically active monoterpenes by gas chromatography. While hydrocarbons were of low solubility (< 35 ppm), oxygenated monoterpenes exhibited solubilities one or two orders of magnitude higher, with ranges of 155–6990 ppm for ketones and of 183–1360 ppm for alcohols. Many monoterpenes are phytotoxic in concentrations under 100 ppm, well below the saturated aqueous concentrations of oxygenated monoterpenes. Therefore, even dilute, unsaturated solutions of monoterpenes, occurring naturally in plant tissues and soil solutions, may act as potent biological inhibitors.     

Effect of rheology and humic acids on the transport of environmental fluids: Potential implications for soil remediation revealed through microfluidics

This study investigated the potential effect of shear rheology and humic acids (HA) on the subsurface transport of polymeric fluids used for the remediation of contaminants. Polymeric fluids were prepared with guar, scleroglucan, and carboxymethyl cellulose (CMC). Guar fluids can be used to suspend reactive particles for contaminant degradation. Fluids prepared with 2.5 g/L of guar in water were viscous, and the crosslinker borax (1 g/L) made them viscoelastic. Microfluidics experiments showed that the increase in elasticity blocked the flow of guar in 350 μm channels. Guar, CMC, or scleroglucan fluids containing sodium thiosulfate can be used to trap toxic Cr(VI) in the subsurface and reduce it to harmless Cr(III). Trapping of Cr(VI) is achieved by the gelation of the fluids upon contact with chromium. Before mixing with chromium, HA did not affect the flow of CMC, guar, and scleroglucan in microfluidic channels. Quartz-crystal microbalance with dissipation monitoring experiments indicates that HA reduced sorption of guar onto silica, potentially promoting the transport of guar fluids in sandy aquifers. While HA slightly decreased the rate of gelation of CMC and scleroglucan upon contact with chromium, it did not affect the fast gelation rate of guar. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48465.     

Upper extremity hemodynamics and sensation with backpack loads

Heavy backpacks are often used in extreme environments, for example by military during combat, therefore completion of tasks quickly and efficiently is of operational relevance. The purpose of this study was to quantify hemodynamic parameters (brachial artery Doppler and microvascular flow by photoplethysmography; tissue oxygenation by near-infrared spectroscopy; arterial oxygen saturation by pulse oximeter) and sensation in upper extremities and hands (Semmes-Weinstein monofilament test and 2-point discrimination test) while wearing a loaded backpack (12 kg) in healthy adults for 10 min. All values were compared to baseline before wearing a backpack. Moderate weight loaded backpack loads significantly decreased upper extremity sensation as well as all macrovascular and microvascular hemodynamic values. Decreased macrovascular and microvascular hemodynamics may produce neurological dysfunction and consequently, probably affect fine motor control of the hands.     

锁骨下动脉闭塞机械再通的方法研究

目的研究锁骨下动脉闭塞血管内机械再通方法和疗效。方法选择３２例症状性锁骨下动脉闭塞患者行血管内机械再通治疗，观察再通率及疗效。结果３２例锁骨下动脉闭塞患者中，用不同方法成功完成血管内机械再通后行血管内支架成形术，术后全部患者后循环缺血症状和上肢缺血症状明显改善。结论采用适当方法行机械再通治疗锁骨下动脉闭塞安全、可行。     

鼻肠减压管插入技术及其在小肠梗阻治疗中的应用

目的探讨鼻肠减压管插入技术及在治疗小肠梗阻中的作用。方法作为主要治疗方法或术前胃肠道减压术在１０例急性小肠梗阻患者中实施了鼻肠减压管插入治疗。治疗在X线透视下实施,鼻肠减压导管经一侧鼻孔插入,在患者体位的配合和配套导丝的引导下,将鼻肠减压管插入至十二指肠屈氏韧带附近或更远处的小肠。结果全部病例鼻肠减压管均顺利通过幽门插入预定位置,平均操作时间１６min（１０～３５min）,经导管治疗后所有患者腹痛、腹胀、呕吐等症状均有不同程度缓解,其中４例（单纯性肠粘连）症状完全消失,２周后拔除导管;３例患者转手术治疗;３例放弃进一步治疗。在插管过程中未出现消化道出血、穿孔等与操作相关的并发症。结论在X线透视下鼻肠减压管插入相对简单,耗时短,在手术前的胃肠减压和治疗单纯粘连性肠梗阻的作用上效果明显,值得采用