Virtual reality: A distributed perspective

This paper considers the implications of Distributed Virtual Reality in terms of user interaction and networking. It is argued that the allocation strategy of data in such a system is one of the fundamental problems faced by designers of Distributed Virtual Reality applications. The need to use experience and techniques drawn from distributed databases is highlighted.     

A regional linear logit fuel demand model for electric utilities

We investigate a short-term forecasting and simulation model of utility fuel demand based on the linear logit model. The forecasting properties of the model are surprisingly good for such a simple econometric model of factor demand. The model ignores the distinctive characteristics of electric utilities (load curves, wheeling, etc.) yet produces remarkably good forecasts at both the national and regional levels. Because the model is based on neoclassical theory it can be used for simulations, making it more useful, and less ad hoc, than a pure forecasting model.     

More than mere mimicry? The influence of emotion on rapid facial reactions to faces.

Within a second of seeing an emotional facial expression, people typically match that expression. These rapid facial reactions (RFRs), often termed mimicry, are implicated in emotional contagion, social perception, and embodied affect, yet ambiguity remains regarding the mechanism(s) involved. Two studies evaluated whether RFRs to faces are solely nonaffective motor responses or whether emotional processes are involved. Brow (corrugator, related to anger) and forehead (frontalis, related to fear) activity were recorded using facial electromyography (EMG) while undergraduates in two conditions (fear induction vs. neutral) viewed fear, anger, and neutral facial expressions. As predicted, fear induction increased fear expressions to angry faces within 1000 ms of exposure, demonstrating an emotional component of RFRs. This did not merely reflect increased fear from the induction, because responses to neutral faces were unaffected. Considering RFRs to be merely nonaffective automatic reactions is inaccurate. RFRs are not purely motor mimicry; emotion influences early facial responses to faces. The relevance of these data to emotional contagion, autism, and the mirror system-based perspectives on imitation is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Nutrient utilization of differing forage-to-concentrate ratios by growing Holstein heifers

Traditionally, high-forage, low-concentrate diets fed ad libitum have been the primary system of feeding dairy heifers. However, high-concentrate diets can be fed at restricted intakes to reach desired rates of gain and increase nutrient efficiency. A total mixed ration containing high corn silage (CS; HCS: 77% CS, 23% concentrate) or low CS (LCS: 67% concentrate, 33% CS) was fed at restricted intakes in 2 trials to evaluate nutrient utilization by growing heifers. In the first trial, 4 ruminally cannulated heifers (298 ± 16 kg of body weight) were fed to study differences in rumen pH, volatile fatty acid and ammonia concentrations, and mass of rumen contents. In situ determinations were made on the total mixed ration and CS. Low CS rations were digested more rapidly in situ when compared with HCS (4.5 vs. 2.3 ± 0.3%/h), and no differences were observed in CS digestibility when incubated in the rumen of heifers fed either ration. Mean rumen pH tended to be lower for LCS than for HCS (5.9 vs. 6.2 ± 0.1). Individual and total rumen volatile fatty acid concentrations and rumen ammonia concentration were not different between treatments. Total mass of rumen contents was lower for LCS. In the second trial, four 6-mo-old heifers (172 ± 14 kg of body weight) and four 12-mo-old heifers (337 ± 10 kg of body weight) were used. Digestibility of dry matter was greater for the LCS than the HCS diet in both age groups (76.3 vs. 71.1% for 12-mo-old heifers; 71.4 vs. 68.9% for 6-mo-old heifers). Apparent digestibility of N was not different between treatments; however, retained N was higher for the LCS diets for both age groups. Fecal output was significantly reduced in the LCS diets for both age groups. Feeding low-forage, high-concentrate diets to growing dairy heifers at restricted intakes, although more highly digestible, resulted in few significant differences in rumen fermentation patterns and lower fecal output.     

Frozen storage stability of antioxidant-treated raw restructured beef steaks made from mature cows

Previous research has shown that beef quality decreased with the age of cattle. In this study, beef trimmings from nine mature cows (n = 9), equally representing three animal age groups (2–4, 6–8, and 10–12 yr), were restructured into steaks formulated with propyl gallate, alone or in combination with a beefy flavoring agent, to enhance palatability and stability during 6 months of frozen storage at −29 °C. Lipid oxidation, rancidity, and loss of beefy flavor in restructured steaks during extended storage were reduced by propyl gallate. The beefy flavoring agent inclusion masked mature, forage-fed beef off-flavors, intensified beefy flavor, and improved steak tenderness, juiciness and cooking yield. Thus, the combination of propyl gallate and beefy flavoring offers an effective means to enhance the palatability and storage stability of restructured beef prepared from mature cows.     

CL-20 performance exceeds that of HMX and its sensitivity is moderate

The explosive performance of ϵ-CL-20 was found to be approximately 14% greater than HMX as determined by cylinder expansion and tantalum plate acceleration experiments. This makes it the most powerful explosive ever tested at small volume expansions of the detonation products. In general CL-20 is more sensitive than HMX. However, the sensitivity of CL-20 to one-dimensional shock loading was found to be similar to HMX.     

Ecogeomorphic interactions of Russian olives (Elaeagnus angustifolia) and point-bar morphology along Powder River,Montana, USA

Point bars are crucial alluvial features that help sustain meandering river ecosystems. They are influenced by interactions among physical processes and biological components, such as riparian vegetation. Understanding the mechanisms underlying these interactions can inform management decisions. The meandering Powder River in southeastern Montana, USA, provides a valuable study system for fluvial interactions because it has no major human alterations. Riparian stands of non-native Russian olive trees (Elaeagnus angustifolia) became noticeable after  ~50-year flood in 1978. Fortuitously, 20 channel cross-sections had been established in 1975 and 1977 and have been surveyed periodically ever since. This temporally extensive dataset was coupled with a spatially extensive dataset of 85 point-bar cross-sections derived from high-resolution LiDAR that enabled evaluation of interactions between Russian olives and point-bar morphology through time and space. Based on published literature and field observations, we hypothesised that an increase in the width of Russian olive stands would result in (1) a decrease in the overall point-bar slope, (2) an increase in point-bar heights and (3) in point-bar toe-slopes. The results indicated that point-bar slopes did decrease with an increase in stand width, supporting the first hypothesis (R² = 0.87). However, point-bar heights decreased with an increase in stand width (R² = 0.63), contradicting the second hypothesis and there was no relation between point-bar toe-slopes and stand width (R² < 0.1). The reverse hypothesis that point-bar morphology controls Russian olive stand widths makes more biophysical sense. Thus, Russian olive stand width increases as the point-bar slope and height decrease (R² = 0.79 and 0.50), which provide a greater area of inundation for colonisation. This study demonstrates that geomorphology is controlling non-native vegetation colonisation along Powder River, but that the subsequent stabilisation associated with Russian oliveexpansion may in turn upset the critical geomorphic balance between bank erosion and point-bar aggradation necessary for a stable meandering system.