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1.
The sex ratio produced by an individual may be a consequence of relative frequencies of genotypes amongst offspring, or may result directly from parental (maternal) control. We analyse the evolutionarily stable sex ratio for a hypothetical organism in which both forms of sex ratio expression can occur. We prove that the point of expression of sex ratio does not affect the evolutionarily stable sex ratio for diploid hosts in populations infected with cytoplasmically inherited sex ratio distorters. 相似文献
2.
Lee J. Hatcher G. Vandenberghe L. Chih-Kong Ken Yang 《Very Large Scale Integration (VLSI) Systems, IEEE Transactions on》2007,15(9):1017-1027
This paper presents a feasible study of fully-integrated switching voltage regulators for power-optimized systems-on-chip (SoCs). In order to evaluate the power efficiency across a number of design variables, a compact macro-model of a regulator is created and validated. A key focus of the study is on the characteristics of the active and passive devices that are needed in order to maximize the efficiency of an on-chip regulator. With the macro-model, geometric programming is used to find the optimal characteristics for a given set of constraints such as load condition, process technology, and area. The achievable efficiencies for various current loads and across a range of technologies from 0.35-mum to 90-nm CMOS process are analyzed. The power efficiency is found to be strongly dependent on the inductor technology and over 70% efficiency is possible with advanced inductor technologies. 相似文献
3.
Juan Xing Pham Van Hung Stephen Symons Muhammad Shahin David Hatcher 《Sensing and Instrumentation for Food Quality and Safety》2009,3(4):211-218
Sprout damage (pre-harvest germination) in wheat results in highly deleterious effects on end-product quality. Alpha-amylase,
the pre-dominant enzyme in the early stage of sprouting has the most damaging effect. This paper introduces a new method using
a SWIR hyperspectral imaging system (1000–2500 nm) to predict the α-amylase activity of individual wheat kernels. Two classes
of Canadian wheat, Canada Western Red Spring (CWRS) and Canada Western Amber Durum (CWAD), with samples of differing degrees
of sprout damage were investigated. Individual kernels were first imaged with the hyperspectral imaging system and then the
α-amylase activity of each kernel was determined analytically. Individual kernel α-amylase activity prediction was significant
(R
2 0.54 and 0.73) for CWAD and CWRS, respectively using Partial Least Square regression on the hyperspectral data. A classification
method is proposed to separate CWRS kernels with high α-amylase activity level from those with low α-amylase activity giving
an accuracy of above 80%. This work shows that hyper/multi-spectral imaging techniques can be used for rapidly predicting
the α-amylase activity of individual kernels, detecting sprouting at early stage. 相似文献
4.
An Inventory of Interpersonal Strengths (IIS) was developed and validated in a series of large college student samples. Based on interpersonal theory and associated methods, the IIS was designed to assess positive characteristics representing the full range of interpersonal domains, including those generally thought to have negative qualities (e.g., introversion, coldness, submissiveness). The 8 subscales (octants) of the 64-item IIS demonstrated good circumplex features and reliability. Tests comparing Big 5 interpersonal factors, Inventory of Interpersonal Problems (IIP), Battery of Interpersonal Capabilities (BIC), and other interpersonal measures demonstrated convergent and discriminant validity and shared interpersonal structure. The IIS accounted for significant additional variance in life satisfaction and quality of personal relationships beyond the IIP and the BIC. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
5.
Perkins T.A. Donaldson Nde.N. Hatcher N.A.C. Swain I.D. Wood D.E. 《IEEE transactions on neural systems and rehabilitation engineering》2002,10(3):158-164
We investigated leg-powered cycling in a recumbent tricycle for a paraplegic using functional electrical stimulation (FES) with the lumbo-sacral anterior root stimulator implant (LARSI). A female complete T9 paraplegic had a stimulator for the anterior L2 to S2 spinal roots (bilaterally) implanted in 1994. She was provided with equipment for daily FES cycling exercise at home. The cycling controller applies a pattern of stimulation in each of 16 crank angle phases. A 7-bit shaft encoder measures the crank angle with adequate precision. Each pattern was originally chosen to give the greatest propulsive force in that position when there was no motion. However, dynamically, some reduction in co-contraction is needed; also the patterns are applied with a preset advance time. Maximal power is obtained with an advance of 250 ms, which compensates for muscle response delay and accommodates changes in cadence (from about 25 to 85 rpm). With this system, she has cycled 1.2 km at a time on gently undulating road. We found that spinal root stimulation gives sufficient control over the muscles in the legs to produce a fluid cycling gait. We propose that root stimulation for leg cycling exercise may be a practicable and valuable function for paraplegics following spinal cord injury. 相似文献
6.
C Reavill JP Hatcher VA Lewis GJ Sanger J Hagan 《Canadian Metallurgical Quarterly》1998,357(2-3):115-120
5-HT4 receptors are concentrated in areas of the brain which are rich in dopamine neuronal markers, which may suggest that they influence motor and reward processes. We tested this hypothesis by examining the effects of a 5-HT4 receptor antagonist, 8-amino-7-chloro-(N-butyl-4-piperidyl)methylbenzo-1,4-dioxan-5-car boxylate hydrochloride (SB-204070-A) on amphetamine- and nicotine-induced locomotor stimulation in intact rats. In rats with unilateral 6-hydroxydopamine-induced lesions of the ascending nigrostriatal dopaminergic projection, SB-204070-A was tested for its effects on amphetamine-induced rotation. SB-204070-A was also tested for its effects on rewarded behaviour maintained by intracranial self-stimulation. SB-204070-A did not alter behaviour under any of these conditions, suggesting a lack of involvement of the 5-HT4 receptor in motor and reward processes. 相似文献
7.
McGuire R. L. Yates E. C. Crandall D. G. Hatcher C. R. 《IEEE transactions on nuclear science》1965,12(1):24-27
A digital system has been built for making precise measurements of scintillator decay times. The approach used is similar to the one developed by Bollinger and Thomas. Time intervals between the start of a gamma-induced scintillation and the detection of a single light photon are measured with a time-to-height converter and stored in a pulse height analyzer. The apparatus has a time resolution of less than 2 nanoseconds, a dynamic range of greater than four decades, and is able to detect both prompt and slow decay components in plastic and liquid scintillators. For all fast scintillators studied, the decay of light intensity over the first decade is approximately exponential; however, measured decay times are shorter than those generally quoted. Results of measurements made on several commercially available scintillators will be presented, including NE 102, Pilot B, Pilot A, and MEL-150C. 相似文献
8.
Solid-state and multidimensional solution-state NMR of solid phase extracted and ultrafiltered riverine dissolved organic matter 总被引:1,自引:0,他引:1
Kaiser E Simpson AJ Dria KJ Sulzberger B Hatcher PG 《Environmental science & technology》2003,37(13):2929-2935
In this study we used multidimensional solution-state NMR to elucidate the differences in the chemical composition of solid phase extracted and ultrafiltered DOM isolates. DOM was isolated from water sampled from an oligotrophic river, the River Tagliamento (Italy). The recovery of total DOM was up to 42% with both isolation techniques. In addition to 1- and 2-D solution-state NMR, we also applied 1-D solid-state 13C NMR spectroscopy for DOM characterization. 13C NMR spectroscopy only produced broad overlapping resonances, thus allowing a bulk characterization of DOM composition. However, it demonstrated that the bulk chemical composition of the two DOM fractions exhibited minor spatial-temporal changes. The 2-D experiments (TOCSY, HMQC) showed that the solid phase extracted hydrophobic DOM contained predominantly aliphatic esters, ethers, and hydroxyl groups, whereas the ultrafiltered DOM was comprised partially of peptides/protein, with further evidence for a small amount of aliphatic/fatty acid material. Sugars were present in both DOM fractions. The results show the two isolation techniques selected for different suites of compounds within the bulk DOM pool. 相似文献
9.
Graphical method for analysis of ultrahigh-resolution broadband mass spectra of natural organic matter, the van Krevelen diagram 总被引:3,自引:0,他引:3
Electrospray ionization mass spectrometry (ESI-MS) is becoming an important tool in the study of natural organic matter (NOM) at the molecular level. Ultrahigh-resolution ESI-MS analyses of NOM often produce very complicated spectra; therefore, visual presentation and structural interpretations of the spectra are difficult. To meet this analytical challenge, we herein propose and demonstrate an approach using the van Krevelen diagram. With this approach, complicated mass spectra can be visualized in a way that allows for (1) possible reaction pathways to be identified and presented, and (2) qualitative analyses on major classes of compounds that comprise ultrahigh-resolution spectra. The qualitative analyses are in a good agreement with results obtained from analyses by other analytical techniques. Additionally, the van Krevelen diagram can be expanded to a 3D plot by using peak intensities or relative intensities as the z-axis. The 3D van Krevelen diagram allows for an evaluation of the relative significance of structurally related compounds. The 3D plot can also be a useful tool for compositional differentiation among samples. 相似文献
10.
In the patients with invasion to the aortic window, we performed operation via median sternotomy combined with anteroaxillar thoracotomy. In such patients with T4 invasion, conventional pneumonectomy could not be performed because of the extensive invasion near the main pulmonary artery trunk. In these patients in this study, complete resection of the involved pulmonary artery could be performed using a vascular clamp without CP bypass. Operative technique was as follows: first, the pericardium was opened and taping of the aorta was applied. When the uninvolved part of the intrapericardial pulmonary artery was long enough to cut, we could use a stapling device, but the stapling device could not be used in many cases because the length of the uninvolved segment was too short to cut the left pulmonary artery. In order to carry out complete resection, it was necessary to clamp the central part of the main pulmonary artery diagonally from the left lower side to the right upper side. The pulmonary arterial stump was closed with continuous 4-0 monofilament mattress and over and over suture. We recommend an aggressive surgical approach for the tumor with invasion to the aortic window, because the prognosis is dismal in nonresected locally advanced lung cancer. 相似文献