Neurocognitive signs in prodromal Huntington disease.

Objective: PREDICT-HD is a large-scale international study of people with the Huntington disease (HD) CAG-repeat expansion who are not yet diagnosed with HD. The objective of this study was to determine the stage in the HD prodrome at which cognitive differences from CAG-normal controls can be reliably detected. Method: For each of 738 HD CAG-expanded participants, we computed estimated years to clinical diagnosis and probability of diagnosis in 5 years based on age and CAG-repeat expansion number (Langbehn, Brinkman, Falush, Paulsen, & Hayden, 2004). We then stratified the sample into groups: NEAR, estimated to be ≤9 years; MID, between 9 and 15 years; and FAR, ≥15 years. The control sample included 168 CAG-normal participants. Nineteen cognitive tasks were used to assess attention, working memory, psychomotor functions, episodic memory, language, recognition of facial emotion, sensory–perceptual functions, and executive functions. Results: Compared with the controls, the NEAR group showed significantly poorer performance on nearly all of the cognitive tests and the MID group on about half of the cognitive tests (p = .05, Cohen's d NEAR as large as ?1.17, MID as large as ?0.61). One test even revealed significantly poorer performance in the FAR group (Cohen's d = ?0.26). Individual tasks accounted for 0.2% to 9.7% of the variance in estimated proximity to diagnosis. Overall, the cognitive battery accounted for 34% of the variance; in comparison, the Unified Huntington's Disease Rating Scale motor score accounted for 11.7%. Conclusions: Neurocognitive tests are robust clinical indicators of the disease process prior to reaching criteria for motor diagnosis of HD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prediction and measurement of soil bidirectional reflectance

A model for soil bidirectional reflectance distribution functions in visible and reflective infrared wavelengths is introduced and compared to data acquired in the field. The model is based on the representation of soil surfaces by a collection of opaque spheres sitting on a Lambertian horizontal surface. The model is not sensitive to increases in the sphere area index beyond a value of 0.4. For comparison, soil reflectance factor data were acquired on a tilled field from many view directions and for a range of solar directions. The observed reflectance factor distributions were consistent with those predicted by the function; maximum reflectance occurred in the antisolar direction and reflectance decreased with increasing phase angle. Increasing the surface roughness by different tillage methods did not substantially alter the directional anisotropy of the soil reflectance factors. The model was fit to the data by a nonlinear least-squares procedure     

Electrically Activated Paper Actuators

This paper describes the design and fabrication of electrically controlled paper actuators that operate based on the dimensional changes that occur in paper when the moisture absorbed on the surface of the cellulose fibers changes. These actuators are called “Hygroexpansive Electrothermal Paper Actuators” (HEPAs). The actuators are made from paper, conducting polymer, and adhesive tape. They are lightweight, inexpensive, and can be fabricated using simple printing techniques. The central element of the HEPAs is a porous conducting path (used to provide electrothermal heating) that changes the moisture content of the paper and causes actuation. This conducting path is made by embedding a conducting polymer (PEDOT:PSS) within the paper, and thus making a paper/polymer composite that retains the porosity and hydrophilicity of paper. Different types of HEPAs (straight, precurved, and creased) achieved different types of motions (e.g., bending motion, accordion type motion). A theoretical model for their behavior is proposed. These actuators have been used for the manipulation of liquids and for the fabrication of an optical shutter.     

Novel last passage time based jitter model with application to low slew rate/high noise ring oscillator

In a ring oscillator, the behaviour in which the output voltage ramp (up/down) of its individual delay cell crosses the threshold, which triggers the next stage delay cell, is crucial in determining the timing jitter, and hence phase noise. Specifically, as the slew rate of the ramp decreases and/or the amount of noise contribution from the transistors in the delay cell increases, the voltage ramp (up or down) has a higher probability of crossing the threshold multiple times, before finally passing it at a time denoted as last passage time, which is more accurate than the conventional first passage time model. This multiple crossing results in a higher jitter. In the past, investigation in last passage time jitter model results in jitter expression that can only be calculated numerically and thus no design guidelines/insights are apparent. In this paper, a novel model is presented with a simple closed form formula, which shows the extra jitter, due to multiple crossing, adds a term that increases as a function of the fourth power of the noise strength/slew rate ratio. The formula is applied to a real life practical low slow rate/high noise ring oscillator which finds application, for example, in random number generator implementation. Corresponding transistor level simulation results agree reasonably well with the model. Furthermore, it is shown that, on example designs, the last passage time approach in this paper can lead to time jitter that is 100 % larger than that due to conventional first passage time model.     

A study on charge reduction in HfO/sub 2/ gate stacks

Charge in metal-organic chemical vapor deposition-grown HfO/sub 2/ gate stacks has been systematically studied using nMOS capacitors. It is found that, for these films, the charge in the stack is mainly concentrated at the interfaces between the layers and is negative at the HfO/sub 2//interfacial layer (IL) interface and positive at the Si/IL interface. In general, the calculated charge densities at both interfaces are of order 10/sup 12/ cm/sup -2/. A forming gas anneal (FGA) reduces both interface charge greatly. The FGA can also significantly reduce the hysteresis and interface state density. The effects of post deposition anneal at various temperatures and under various ambients have also been studied. It is found that a high-temperature dilute oxidizing ambient anneal followed by an FGA reduces the charge at both interfaces.     

Detection Probability Estimation of Directional Antennas and Omni-Directional Antennas

This paper studies the problem of detection of directional antennas and omni-directional antennas by hostile detection systems. We present a model for calculating the probability of detecting a transmitter at arbitrary location around the transmitter. Our study shows that, if a directional antenna employs the same transmit power as an omni-directional antenna, the directional antenna can not decrease the probability of being detected. In some scenarios, a directional antenna is more likely to be detected than an omni-directional antenna. However, if a directional antenna provides the same Effective Isotropic Radiated Power in the direction of the receiver as an omni-directional antenna, the transmit power needed by a directional antenna to send data is much less than that of an omni-directional antenna. In this scenario, the probability of detecting a directional antenna is reduced by over 90%. This reveals that directional antennas can be used to build a secure path to send data at low probability of being detected by adversaries.     

光纤连接器:不仅适用于高速传输

目前光纤电路的应用范围不只是限于极远距离的高速率数据传输.标准的光纤连接器正在逐渐扩展其应用范围,从激光外科手术到水下摄像设备,从石油化工厂的外界环境到原子反应堆的内部,我们都可以找到光纤连接器的应用.本文的目的是想给刚进入光纤连接器领域的工程师们提供一些知识,帮助他们认识连接器的基本类型和安装风格,本文所介绍的内容可以为读者提供连接器性能和价格方面的参考.     

Intelligibility improvements using binaural diverse sub-bandprocessing applied to speech corrupted with automobile noise

The paper reports on experiments assessing the capability of a diverse processing, multi-microphone sub-band adaptive signal processing scheme for improving the intelligibility of speech corrupted with automobile noise. Results from formal listening tests demonstrate a significant improvement in the intelligibility and quality of the processed speech. Spoken digits corrupted with automobile noise at a low and a high signal-to-noise ratio were used with two commercial speech recognisers. The results obtained with the recognisers did not demonstrate any statistically significant improvement due to processing in sub-bands     

Burst reduction properties of rate-control throttles: downstreamqueue behavior

Considers rate-based flow control throttles feeding a sequence of single server infinite capacity queues. Specifically, the authors consider two types of throttles, the token bank and the leaky bucket. They show that the cell waiting times at the downstream queues are increasing functions of the token buffer capacity. These results are established when the rate-based throttles have finite capacity data buffers as well as infinite capacity buffers. In the case that the data buffer has finite capacity, they require that the sum of the capacities of the data buffer and token buffer be a constant. Last, they establish similar results for the process of number of losses at the last downstream queue in the case that the waiting buffer has finite capacity