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101.
Groundwater was measured 70 times in two years at 10 sites as it flowed 50 m over an accumulation of travertine (CaCO3) before reaching the Mad River. At source, the groundwater was relatively cool (6.77 ± 2.89 °C), slightly acidic ( pH 6.86 ± 0.22), and had a moderately high specific conductivity (606 ± 51 μS). Degassing was assessed from increases in pH, and CaCO3 deposition was assessed from decreasing conductivity. After flowing over the experimental site, degassing had increased pH to 8.04 ± 0.16 (P < 0.001), which was similar to river water (pH 8.07 ± 0.30). Concurrently, CaCO3 deposition decreased conductivity to 577 ± 43 μS (P < 0.001) but this was still higher (P < 0.001) than river water (494 ± 72). Seasonal changes in air temperature affected the rate of degassing. The pH was correlated with air temperature (r = 0.15, P < 0.001) while conductivity was correlated with pH (r = − 0.27, P < 0.001), but no direct relationship of air temperature with conductivity was detected. Groundwater entering the river after atmospheric exposure had a fairly constant temperature (7.05 ± 1.22 °C) despite seasonal changes in air temperature, thus warming the river in winter (up to day 100 and after day 300) and cooling it in summer (from days 140 to 260). Degassing and CaCO3 deposition in springs without travertine was similar to that observed in the study stream over travertine. These groundwater inflows provide favorable pH and temperature conditions for brook trout. 相似文献
102.
Vladimir Shestak Edwin K.P. Chong Anthony A. Maciejewski Howard Jay Siegel 《Journal of Parallel and Distributed Computing》2012
The problem of finding efficient workload distribution techniques is becoming increasingly important today for heterogeneous distributed systems where the availability of compute nodes may change spontaneously over time. Resource-allocation policies designed for such systems should maximize the performance and, at the same time, be robust against failure and recovery of compute nodes. Such a policy, based on the concepts of the Derman–Lieberman–Ross theorem, is proposed in this work, and is applied to a simulated model of a dedicated system composed of a set of heterogeneous image processing servers. Assuming that each image results in a “reward” if its processing is completed before a certain deadline, the goal for the resource allocation policy is to maximize the expected cumulative reward. An extensive analysis was done to study the performance of the proposed policy and compare it with the performance of some existing policies adapted to this environment. Our experiments conducted for various types of task-machine heterogeneity illustrate the potential of our method for solving resource allocation problems in a broad spectrum of distributed systems that experience high failure rates. 相似文献
103.
A method for determining the authenticity of subterranean termite trail pheromones is suggested and utilized to verify the presence of trail pheromones inReticulitermes virginicus, R. flavipes, andR. tibialis. In addition, a possible trail pheromone has been demonstrated forCoptotermes formosanus. A choice bioassay method shows that the above trail pheromones are species specific. 相似文献
104.
Bandi S.P.R. Washburn C. Mukund P.R. Kolnik J. Paradis K. Howard S. Burleson J. 《Microwave and Wireless Components Letters, IEEE》2006,16(5):290-292
One of the most challenging problems encountered in developing RF circuits is accurate prediction of MOS behavior at microwave signal and data frequencies. An attempt is made in this work to accurately model the device input impedance for the 1-20-GHz frequency range. The effect of device length and single-leg width on the input impedance is studied with the aid of extensive measured data obtained from devices built in 0.11-/spl mu/m and 0.18-/spl mu/m technologies. The measured data illustrates that the device input impedance has a nonlinear frequency dependency. It is also shown that this variation in input impedance is a result of gate poly-silicon depletion, which can be modeled by an external RC network connected at the gate of the device. Excellent agreement between the simulation results and the measured data validates the model in the device active region. 相似文献
105.
Controversies are rampant in contemporary psychology concerning the appropriate method for observing consciousness and the role inner experience should play in psychological theorizing. These conflicting orientations reflect, in part, methodological differences between natural science and human science interpretations of psychology. Humanistic psychology and philosophical phenomenology both employ a human science approach to psychology that seeks to explain behavior in terms of a person's subjective existence. Maslow's and Heidegger's formulations are both fulfillment theories in that they specify moral values that suggest how life ought to be lived. Natural science methodology rejects the possibility that moral imperatives can be validated, whereas human science methodology allows phenomenological convictions to justify recommendations about a fulfilled life and a good society. The social role of psychology is analyzed within the framework of phenomenological convictions and scientific truth. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
106.
Martins Silvia S.; Mazzotti Guido; Chilcoat Howard D. 《Canadian Metallurgical Quarterly》2005,13(3):244
This study aims to estimate changes in the prevalence of ecstasy use over time, analyze the overlap of ecstasy use and other drug use, and compare other drug use in ecstasy versus marijuana users. The authors hypothesized that ecstasy users early in the "epidemic" would be polydrug users and that associations between ecstasy and other drug use would diminish as the prevalence of ecstasy use increased. Data were drawn from public use data files from the 1995, 1997, 1999, and 2001 National Household Survey on Drug Abuse. Ecstasy use increased in the U.S. population and the prevalence was greater in younger age groups. Ecstasy users were likely to use a variety of other drugs; however, association of ecstasy use with other drug use was strongest early in the "epidemic," diminishing as the number of new users increased. Later, more drug-naive adolescents and young adults began experimenting with ecstasy. These results can orient prevention strategies that target ecstasy users. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
107.
BillHoward 《个人电脑》2003,9(6):149-149
有谁相信Intel和MIcrosoft所说的一切吗7我也不相信。所以我对过去两周PC Magazine实验室的结果感到吃惊:配备新型1.6GHz Intel Pentium M CPU的centnno系统堪与配备3.06GHz台式机芯片的笔记本媲美,Centrino系统的电池寿命几乎是近期的高端笔记本的两倍。Centrino笔记本几乎具备我们所希望的以及Intel所声称的一切优点。 相似文献
108.
109.
This paper introduces the ideas behind BPML, the business process modelling language published by BPMI. BPML provides a process-centric (as opposed to a datacentric) metalanguage and execution model for business systems. It is underpinned by a strong mathematical foundation, the pi-calculus. The current paper is derived from supplementary appendices to a book which describes a ‘third wave’ approach to business process management [Business Process Management: The Third Wave, 2003]. The aim is to model business processes directly in an executable form, so that the mobility and mutability inherent in business behaviour is reflected and supported in the corresponding IT systems, erasing the present IT-business divide. 相似文献
110.
Howard Bowman Helen Cameron Peter King Simon Thompson 《Formal Methods in System Design》2003,22(1):5-38
This paper explores a formalism for describing a wide class of multimedia document constraints, based on an interval temporal logic. We describe the requirements that arise from the multimedia documents application area, and we illustrate these requirements using several examples. Then we present the temporal logic formalism that we use. This logic extends existing interval temporal logic with a number of new features: actions, framing of actions, past operators, a projection-like operator called filter and a new handling of interval length. The notation is applied to the specification of the examples, and in particular a set of logical manipulations, providing feedback to an author, is presented. A model theory, logic and satisfaction relation are defined for the notation. 相似文献