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191.
The blood concentration of 1,8-cineole and its metabolites was measured in six male brushtail possums while they voluntarily
fed on diets laced with varying concentrations of cineole for 3 d. On the third day, blood samples were collected during and
after each bout of feeding for 3 hr. Blood cineole was measured by using headspace solid-phase microextraction (SPME), while
cineole metabolites were measured by liquid–liquid extraction followed by gas chromatography-mass spectroscopy. Feeding patterns
were measured by continual recording of residual food weight and time. Cineole absorption was rapid, resulting in a peak blood
concentration at the end of each feeding bout. The blood concentration of cineole did not exceed a critical value (51.8 ±
14.1 μmol/l) regardless of the concentration in the diet. Food and, therefore, cineole intake was regulated. The amount of
food ingested in the first feeding bout decreased from 236 ± 52 g on the control diet to 36 ± 20 g on the 4% cineole diet.
The amount of cineole ingested in the first bout (1.18 ± 1.10 g) was the same regardless of the dietary concentration and
was controlled by the size of the meal. Total food eaten during the 7-hr feeding session decreased by 64% from 368 ± 94 g
(control diet) to 131 ± 52 g (4% diet). Total cineole intake increased from 2.47 ± 0.60 g (1% diet) to 5.05 ± 2.41 g (4% diet).
Cineole metabolites accumulated throughout the sampling period and were generally still rising at the end of blood sampling
period. Blood levels of metabolites were at least 10-fold higher than cineole levels. The immediate control of feeding seems
to be regulated by blood levels of cineole, whereas metabolites are likely to be more important in regulating the chronic
ingestion of cineole. 相似文献
192.
An introduction to the special issue on the multilevel measurement model (MMM) is provided. The two- and three-level multilevel models for continuous outcomes are reviewed. The extension to the hierarchical generalized linear model and its use as a multilevel measurement model for dichotomous measurement indicators is demonstrated. The six articles in the special issue are described. 相似文献
193.
Daniel Kroening Natasha Sharygina Stefano Tonetta Aliaksei Tsitovich Christoph M. Wintersteiger 《Formal Methods in System Design》2013,42(3):221-261
This paper presents algorithms for program abstraction based on the principle of loop summarization, which, unlike traditional program approximation approaches (e.g., abstract interpretation), does not employ iterative fixpoint computation, but instead computes symbolic abstract transformers with respect to a set of abstract domains. This allows for an effective exploitation of problem-specific abstract domains for summarization and, as a consequence, the precision of an abstract model may be tailored to specific verification needs. Furthermore, we extend the concept of loop summarization to incorporate relational abstract domains to enable the discovery of transition invariants, which are subsequently used to prove termination of programs. Well-foundedness of the discovered transition invariants is ensured either by a separate decision procedure call or by using abstract domains that are well-founded by construction. We experimentally evaluate several abstract domains related to memory operations to detect buffer overflow problems. Also, our light-weight termination analysis is demonstrated to be effective on a wide range of benchmarks, including OS device drivers. 相似文献
194.
Dr. Hanna Krasnova Natasha F. Veltri Klaus Spengler Prof. Oliver Günther 《WIRTSCHAFTSINFORMATIK》2013,55(3):159-173
“Deal of the Day” (DoD) platforms have quickly become popular by offering savings on local services, products and vacations. For merchants, these platforms represent a new marketing channel to advertise their products and services and attract new customers. DoD platform providers, however, struggle to maintaining a stable market share and profitability, because entry and switching costs are low. To sustain a competitive market position, DoD providers are looking for ways to build a loyal customer base. However, research examining the determinants of user loyalty in this novel context is scarce. To fill this gap, this study employs Grounded Theory methodology to develop a conceptual model of customer loyalty to a DoD provider. In the next step, qualitative insights are enriched and validated using quantitative data obtained in a survey with 202 DoD users. We find that customer loyalty is in large part driven by monetary incentives, but can be eroded if impressions from merchant encounter are below expectations. In addition, enhancing the share of deals relevant for consumers, i.e. signal-to-noise ratio, and mitigating perceived risks of a transaction emerge as challenges. Beyond theoretical value, our results offer practical insights into how customer loyalty to a DoD provider can be promoted. 相似文献
195.
Ågotnes Thomas Alechina Natasha Galimullin Rustam 《Journal of Logic, Language and Information》2022,31(2):141-166
Journal of Logic, Language and Information - Public announcement logic (PAL) is an extension of epistemic logic with dynamic operators that model the effects of all agents simultaneously and... 相似文献
196.
Richard D. Johnson Natasha F. Veltri Steven Hornik 《International journal of human-computer interaction》2013,29(6):595-612
This study examined how social cues in an interface and user gender affected attributions of responsibility for the process and outcomes of interacting with a computer. Using a 2 × 2 between-subjects laboratory design, 391 participants were randomly assigned to work with a computer that utilized either a traditional interface or an interface designed to include higher social cues. The results of this study indicated that those who interacted with the interface with greater social cues made greater attributions of responsibility to the computer. In addition, women were more likely to ascribe responsibility to the computer. Results did not support an interaction between gender and interface design. Implications for theory and practice are discussed. 相似文献
197.
OBJECTIVE: This study examined the effect of two in-vehicle information systems (IVIS) on signal detection in the visual, auditory, and tactile modalities; established whether the detrimental effects of an IVIS on driving could be quantified by these detection tasks; and examined the effect of stimulus modality on signal detection. BACKGROUND: The peripheral detection task has been used widely for assessing the effects of an IVIS on driving. However, performance on this task relies on drivers' ability to see a series of LEDs, which can be problematic in field tests (e.g., on sunny days). METHOD: Participants responded to one of three detection tasks during a simulated driving experiment. The effect of IVIS interaction on these detection tasks was also measured. Reduced performance in the detection tasks was assumed to indicate a decline in drivers' ability to handle sudden events in the driving task. RESULTS: Response time to all detection tasks increased by around 200 ms when drivers performed the IVIS tasks, as compared with baseline driving. Analyses of variance and comparison of effect sizes showed the effects of these two IVISs to be the same across the three detection tasks. CONCLUSION: These detection tasks are useful for quantifying the safety of an IVIS during driving. The absence of a difference in signal detection by modality suggests that performance on these tasks relies on general attentional resources and is not modality specific. APPLICATION: The signal detection tasks employed here should be further investigated for their suitability in assessing the safety of in-vehicle systems. 相似文献
198.
Distribution of phthalate esters in a marine aquatic food web: comparison to polychlorinated biphenyls 总被引:11,自引:0,他引:11
Mackintosh CE Maldonado J Hongwu J Hoover N Chong A Ikonomou MG Gobas FA 《Environmental science & technology》2004,38(7):2011-2020
Dialkyl phthalate esters (DPEs) are widely used chemicals, with over 4 million tonnes being produced worldwide each year. On the basis of their octanol-water partition coefficients (Kow), which range from 10(1.61) for dimethyl phthalate to 10(9.46) for di-iso-decyl phthalate, certain phthalate esters have the potential to bioconcentrate and biomagnify in aquatic food webs. However, there are no reported field studies on the trophodynamics of phthalate ester in aquatic food webs. This study reports the distribution of 8 individual phthalate esters (i.e., dimethyl, diethyl, di-isobutyl, di-n-butyl, butylbenzyl, di(2-ethylhexyl), di-n-octyl, and di-n-nonyl) and 5 commercial isomeric mixtures (i.e., di-iso-hexyl (C6), di-iso-heptyl (C7), di-iso-octyl (C8), di-iso-nonyl (C9), and di-iso-decyl (C10)) in a marine aquatic food web. DPE concentrations were determined in 18 marine species, representing approximately 4 trophic levels. Co-analysis of DPEs and 6 PCB congeners (i.e., PCB-18, 99, 118, 180, 194, and 209) in all samples produced a direct comparison of the bioaccumulation behavior of PCBs and DPEs. Lipid equivalent concentrations of the PCBs increased with increasing trophic position and stable isotope ratios (delta15N). The Food-Web Magnification Factor (FWMF) of the PCB congeners ranged from 1.8 to 9.5. Lipid equivalent concentrations of low and intermediate molecular weight DPEs (i.e., C1-C7 DPEs: dimethyl, diethyl, di-iso-butyl, di-n-butyl, benzylbutyl, and C6 and C7 isomers) did not exhibit statistically significant trends with trophic position or stable nitrogen isotope ratios (delta15N) in the food web and FWMFs were not significantly different from 1. Lipid equivalent concentrations of the high-molecular-weight DPEs (i.e., C8-C10 DPEs: di(2-ethylhexyl), di-n-octyl, di-n-nonyl, C8, C9, and C10) declined significantly with increasing trophic position and stable isotope ratios (delta15N), producing FWMFs between 0.25 and 0.48. These results show that all DPEs tested did not biomagnify in the studied aquatic food web whereas PCBs did biomagnify. 相似文献
199.
200.
Two bodies of work on postpartum depression are reviewed. Quantitative, positivist studies examine the epidemiology and etiology of postpartum depression, adopt a medical model of explanation, and conceptualize postpartum depression as a pathological response to motherhood. Social scientific studies, some from a feminist perspective, explore women's experiences of postpartum depression predominantly, but not exclusively, within a qualitative tradition. Postpartum depression is theorized as a "normal" response to motherhood and is linked to "public-world" losses of identity, autonomy, independence, power, and paid employment. Drawing on a qualitative study of 40 women's experiences of motherhood, this article argues that not all women become depressed following childbirth and women's varying responses to motherhood need to be recognized. A relational re-framing of postpartum depression is put forward. From this perspective, postpartum depression occurs when women are unable to experience, express, and validate their feelings and needs within supportive, accepting, and non-judgmental interpersonal relationships and cultural contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献