A tool was developed for structured and detailed analysis of video data from user tests of interactive systems. It makes use of a table format for representing an interaction at multiple levels of abstraction. Interactions are segmented based on threshold times for pauses between actions. Usability problems are found using a list of observable indications for the occurrence of problems. The tool was evaluated by having two analysts apply it to three data sets from user tests on two different products. The segmentation technique proved to yield meaningful segments that helped in understanding the interaction. The interaction table was explicit enough to discuss in detail what had caused the differences in the analysts' lists of usability problems. The results suggested that the majority of differences were caused by unavoidable differences in interpretations of subjects' behaviour and that only minor improvements should be expected by refining the tool. 相似文献
Experiment 1 established conditioned place preference (CPP) control procedures for young precocial domestic fowl (test day age?=?13–25 days). Chicks displayed a preference (greater choice time) for white stimulus cards on first exposure to white versus red cards and equivalent preference for these stimulus cards after 6 exposures. Chicks in Experiment 2 displayed a cocaine CPP at each dose (0.5, 1.0, and 2.0 mg/kg intraperitoneally) after 6 cocaine-red card and 6 saline-white card pairings. This CPP decreased and was no longer significant over 2 additional nonreinforced test days. Experiment 3 results replicated the cocaine CPP (2.0 mg/kg) and demonstrated that the CPP did not develop when cocaine was administered several hours after card exposure. To our knowledge, these results are the first to demonstrate drug CPP in a nonmammalian model and support the notion that drug reinforcement processes are highly conserved. This precocial avian model may prove a useful addition to existing altricial models for the study of determinants of human drug use and abuse. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
The primary products, 9- and 13-hydroperoxy-octadecadienoic acids, from lipoxygenase catalyzed oxidation of linoleic acid,
were converted into the trimethylsilyl ethers of methyl 9- and 13-hydroxystearates which were completely separated by gas
chromatography on an OV-17 methyl silicone (50% phenyl groups), capillary column. 相似文献
It has recently been shown that tocotrienols are the components of vitamin E responsible for inhibiting the growth of human
breast cancer cells in vitro, through an estrogen-independent mechanism. Although tocotrienols act on cell proliferation in a dose-dependent manner and
can induce programmed cell death, no specific gene regulation has yet been identified. To investigate the molecular basis
of the effect of tocotrienols, we injected MCF-7 breast cancer cells into athymic nude mice. Mice were fed orally with 1 mg/d
of tocotrienol-rich fraction (TRF) for 20 wk. At end of the 20 wk, there was a significant delay in the onset, incidence,
and size of the tumors in nude mice supplemented with TRF compared with the controls. At autopsy, the tumor tissue was excised
and analyzed for gene expression by means of a cDNA array technique. Thirty out of 1176 genes were significantly affected.
Ten genes were down-regulated and 20 genes up-regulated with respect to untreated animals, and some genes in particular were
involved in regulating the immune system and its function. The expression of the interferon-inducible transmembrane protein-1
gene was significantly up-regulated in tumors excised from TRF-treated animals compared with control mice. Within the group
of genes related to the immune system, we also found that the CD59 glycoprotein precursor gene was up-regulated. Among the
functional class of intracellular transducers/effectors/modulators, the c-myc gene was significantly down-regulated in tumors
by TRF treatment. Our observations indicate that TRF supplementation significantly and specifically affects MCF-7 cell response
after tumor formation in vivo and therefore the host immune function. The observed effect on gene expression is possibly exerted independently from the
antioxidant activity typical of this family of molecules. 相似文献
Musculoskeletal disorders are more common among women than among men. When comparing the difference between men and women in the prevalence of musculoskeletal disorders, methodological problems arise as men and women seldom perform the same type of activities, neither at work nor at home.
The main objective of this cross-sectional case study was to compare work technique and self-reported musculoskeletal symptoms between men and women performing the same type of work tasks within a metal industry. Other factors, such as leisure activities, were also taken into consideration. Three data collection methods were used; questionnaire, interviews and systematic observations. The results from the observations revealed that women worked more frequently and during longer times with their hands above shoulder height than men. Working with hands above shoulder height is considered a risk factor for neck and shoulder disorders according to previous studies. Workplace design factors were probably a reason for differences in working technique between men and women. A higher proportion of women than men reported shoulder symptoms. Women spent more time on household activities than men, which indicates a higher total workload in paid and unpaid work. 相似文献
Simple and comprehensive two-dimensional (2D)-HPLC was studied in a reversed-phase mode using monolithic silica columns for second-dimension (2nd-D) separation. Every fraction from the first column, 15 cm long (4.6-mm i.d.), packed with fluoroalkylsilyl-bonded (FR) silica particles, was subjected to the separation in the 2nd-D using one or two octadecylsilylated (C(18)) monolithic silica columns (4.6-mm i.d., 3 cm). Monolithic silica columns in the 2nd-D were eluted at a flow rate of up to 10 mL/min with separation time of 30 s that meets the fractionation every 15-30 s at the first dimension (1st-D) operated at a flow rate of 0.4-0.8 mL/min. Three cases were studied. (1) In the simplest scheme of 2D-HPLC, effluent of the 1st-D was directly loaded into an injector loop of 2nd-D HPLC for 28 s, and 2 s was allowed for injection. (2) Two six-port valves each having a sample loop were used to hold the effluent of the 1st-D alternately for 30 s for one 2nd-D column to effect comprehensive 2D-HPLC without the loss of 1st-D effluent. (3) Two monolithic silica columns were used for 2nd-D by using a switching valve and two sets of 2nd-D chromatographs separating each fraction of the 1st-D effluent with the two 2nd-D columns alternately. In this case, two columns of the same stationary phase (C(18)) or different phases, C(18) and (pentabromobenzyloxy)propylsilyl-bonded (PBB), could be employed at the 2nd-D, although the latter needed two complementary runs. The systems produced peak capacity of approximately 1000 in approximately 60 min in cases 1 and 2 and in approximately 30 min in case 3. The three stationary phases, FR, C(18), and PBB, showed widely different selectivity from each other, making 2D separations possible. The simple and comprehensive 2D-HPLC utilizes the stability and high efficiency at high linear velocities of monolithic silica columns. 相似文献
The samples are digested in nitric acid and evaporated to near dryness. Hydrogen peroxide is then added for complete oxidation of fat residues. Determination of metals is performed by flameless AAS with graphite furnace and results evaluated by the method of standard addition. The method is suitable for the determination of some non-volatile metals in fish livers in which the amount of available sample is limited; Pb, Cd, Cu and Zn have been determined in such samples. 相似文献
In the course of miniaturization of electronic and microfluidic devices, reliable predictions of the stability of ultrathin films have a strategic role for design purposes. Consequently, efficient computational techniques that allow for a direct comparison with experiment become increasingly important. Here we demonstrate, for the first time, that the full complex spatial and temporal evolution of the rupture of ultrathin films can be modelled in quantitative agreement with experiment. We accomplish this by combining highly controlled experiments on different film-rupture patterns with computer simulations using novel numerical schemes for thin-film equations. For the quantitative comparison of the pattern evolution in both experiment and simulation we introduce a novel pattern analysis method based on Minkowski measures. Our results are fundamental for the development of efficient tools capable of describing essential aspects of thin-film flow in technical systems. 相似文献
There is growing interest in complicated grief reactions as a possible new diagnostic category for inclusion in the Diagnostic and Statistical Manual of Mental Disorders. However, no research has yet shown that complicated grief has incremental validity (i.e., predicts unique variance in functioning). The authors addressed this issue in 2 studies by comparing grief, depression, and posttraumatic stress disorder (PTSD) symptoms with different measures of functioning (interviewer ratings, friend ratings, self-report, and autonomic arousal). The 1st study (N = 73) used longitudinal data collected at 4 and 18 months postloss, and the 2nd study (N = 447) used cross-sectional data collected 2.5-3.5 years postloss. With depression and PTSD controlled, grief emerged as a unique predictor of functioning, both cross-sectionally and prospectively. The findings provide convergent support for the incremental validity of complicated grief as an independent marker of bereavement-related psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献