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201.
We study theoretically the light-scattering efficiency of paper coatings made of starch acetate pigments. For the light-scattering code we use a discrete dipole approximation method. The coating layer is assumed to consists of roughly equal-sized spherical pigments packed either at a packing density of 50% (large cylindrical slabs) or at 37% or 57% (large spheres). Because the scanning electron microscope images of starch acetate samples show either a particulate or a porous structure, we model the coatings in two complementary ways. The material can be either inside the constituent spheres (particulate case) or outside of those (cheeselike, porous medium). For the packing of our spheres we use either a simulated annealing or a dropping code. We can estimate, among other things, that the ideal sphere diameter is in the range 0.25-0.4 microm. 相似文献
202.
Loading changes in time-based parameters of glottal flow waveforms in different ergonomic conditions
The effects of prolonged (5 x 45 min) reading in different environmental and ergonomic conditions on time-based glottal waveform parameters of normal female and male subjects (n = 80) were studied. The exposure groups (n = 5 females and males per cell) consisted of eight combinations of the following factors: (1) normal (< 65 dB) or high (> 65 dB) speech output level; (2) sitting or standing posture; (3) low (25 +/- 5%) or high (65 +/- 5%) relative humidity of ambient air. Two rest (morning and noon) and three loading (two in the morning and one in the afternoon) samples were recorded and analyzed. The glottal waveforms were obtained by inverse filtering of the acoustical signal using an automatic method. The following time based parameters were analyzed from the estimate glottal flow waveform: (1) length of fundamental period; (2) open quotient; (3) speed quotient, and (4) closing quotient. The analysis was based on inverse filtering of the first stressed syllable of 'paappa' word repeated 3 x 5 times with normal, maximally soft and maximally loud phonation. Humidity was a significant factor in several instances. The interactions between gender and the loading factors were striking. 相似文献
203.
This study described nursing decision-making models and variables related to these models. For this purpose a 56-item Likert-type questionnaire was constructed according to the Dreyfus model of skill acquisition as applied to nursing by Benner and information processing theory. The target group consisted of 100 registered nurses working in inpatient clinics and 100 public health nurses working in preventive health care. The decision-making variables explored were nurses' experience, education and knowledge as well as the nature of the nursing task and context. The results revealed four different types of decision-making: (a) unquestioning/questioning decision-making, (b) creative-diversive decision-making, (c) patient/nurse-oriented decision-making, and (d) rule- and situation-based decision-making. The most important factors related to decision-making were experience and the nature of the nursing task and context. 相似文献
204.
Graziano William G.; Jensen-Campbell Lauri A.; Finch John F. 《Canadian Metallurgical Quarterly》1997,73(2):392
The self can be conceptualized as a mediating agent that translates personality into situated goal-directed activities and adaptation. This research used a level-of-analysis approach to link personality dimensions (Level 1) to self-systems (Level II) and to teacher ratings of adjustment in African American, Mexican American, and European American students (N?=?317). The authors hypothesized that links among aspects of self-esteem and teacher ratings of adjustment would be domain specific, and those links to dimensions of the 5-factor model would reflect the domain specificity. Structural equation modeling corroborated hypotheses about domain specificity in links between adjustment and 5-factor dimensions. Results were discussed in terms of levels of analysis for personality structure, personality development, and age-related adaptations to social contexts. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
205.
In practical situations, flow shops usually have some policies on rescheduling previously scheduled jobs. This article compares three of these rescheduling policies: an unrestricted one where previously scheduled jobs can be moved freely, one where jobs can only be moved forward in the schedule, and one where jobs that have already been scheduled cannot be moved at all. The comparison is performed by considering the minimization of tardiness. While unrestricted rescheduling should generally give the best solution, moving jobs only forward can be more practical as in general production, material orders can be delayed but seldom advanced. This article points out that moving jobs only forward is not significantly worse than the unrestricted scheduling. When cases with small numbers of jobs and machines are analysed both policies give similar tardiness. Numerical experiments show that the differences between these two rescheduling policies are rather small in larger problems as well. 相似文献
206.
Heikki Mansikka Petteri Simola Kai Virtanen Don Harris Lauri Oksama 《Ergonomics》2016,59(10):1344-1352
Fighter pilots’ heart rate (HR), heart rate variation (HRV) and performance during instrument approaches were examined. The subjects were required to fly instrument approaches in a high-fidelity simulator under various levels of task demand. The task demand was manipulated by increasing the load on the subjects by reducing the range at which they commenced the approach. HR and the time domain components of HRV were used as measures of pilot mental workload (PMWL). The findings of this study indicate that HR and HRV are sensitive to varying task demands. HR and HRV were able to distinguish the level of PMWL after which the subjects were no longer able to cope with the increasing task demands and their instrument landing system performance fell to a sub-standard level. The major finding was the HR/HRV’s ability to differentiate the sub-standard performance approaches from the high-performance approaches.
Practitioner Summary:
This paper examined if HR and HRV were sensitive to varying task demands in a fighter aviation environment and if these measures were related to variations in pilot’s performance. 相似文献
207.
208.
Jenni Soukka Lauri Polari Marko Kalliomäki Lotta Saros Teemu D. Laajala Tero Vahlberg Diana M. Toivola Kirsi Laitinen 《Molecular nutrition & food research》2023,67(15):2200446
Scope
Modifying the composition of colostrum by external factors may provide opportunities to improve the infant's health. Here, we evaluated how fish oil and/or probiotics supplementation modify concentrations of colostrum immune mediators and their associations with perinatal clinical factors on mothers with overweight/obesity.Methods and results
Pregnant women were randomized in a double-blind manner into four intervention groups, and the supplements were consumed daily from early pregnancy onwards. Colostrum samples were collected from 187 mothers, and 16 immune mediators were measured using bead-based immunoassays. Interventions modified colostrum composition; the fish oil+probiotics group had higher concentrations of IL-12p70 than probiotics+placebo and higher FMS-like tyrosine kinase 3 ligand (FLT-3L) than fish oil+placebo and probiotics+placebo (one-way analysis of variance, post-hoc Tukey's test). Although the fish oil+probiotics group had higher levels of IFNα2 compared to the fish oil+placebo group, these differences were not statistically significant after correction for multiple testing. Multivariate linear model revealed significant associations between several immune mediators and the perinatal use of medication.Conclusion
Fish oil/probiotics intervention exerted a minor effect on concentrations of colostrum immune mediators. However, medication during the perinatal period modulated the immune mediators. These changes in colostrum's composition may contribute to immune system development in the infant. 相似文献209.
Merivirta LO Koort JM Kivisaari M Korkeala H Björkroth KJ 《International journal of food microbiology》2005,101(2):145-152
Microbiological and sensory changes in vacuum-packaged charcoal-broiled river lampreys from three lamprey processing plants were monitored as a function of time at 8 degrees C. The lampreys were examined every 7 days up to 8 weeks for aerobic plate count (APC) and lactic acid bacteria (LAB). The highest mean APC and LAB were 6.01 log CFU/g and 4.86 log CFU/g, respectively. Only 6 out of 15 lots reached an APC value of 7.0 log CFU/g during storage. The sensory scores remained at the baseline levels after 8 weeks' storage. Twenty-seven isolates were randomly picked from MRS agar and identified to species level using a 16S and 23S rDNA HindIII RFLP (ribotyping) database and sequencing of the 16S rRNA gene if no database match was obtained. Twelve of the 27 isolates were identified as Lactobacillus curvatus subsp. curvatus, and two Leuconostoc mesenteroides and one Weissella halotolerans strain were also detected. Twelve isolates were not identified by the LAB database. However, they possessed very high (99.9%) 16S gene sequence similarity with either Staphylococcus warneri or Staphylococcus pasteuri type strains. The LAB detected, with the exception of W. halotolerans, have commonly been associated with spoilage of fishery products, but in these vacuum-packaged lampreys, they were not the dominant organisms within the developing spoilage population. 相似文献
210.
Dominik Röser Lauri SikanenAntti Asikainen Heikki ParikkaKari Väätäinen 《Biomass & bioenergy》2011,35(11):4570-4580
At present, the utilization of timber in the Northern part of the Scottish Highlands is low due to a lack of a wood utilizing industry. As a consequence, the majority of forest owners do not receive any income from timber and in some cases stumpage prices can even be negative. At the same time, increasing prices of oil, gas and electricity pose a great challenge for local industries and homeowners. The establishment of wood fueled heating systems is therefore expected to improve the situation and at the same time create a market for the local timber resources. Consequently, a local energy source to produce heat and electricity at a competitive price would have positive benefits for both local industries and forest owners. Due to the current lack of competition, roundwood could be chipped for fuel, which has many associated benefits compared to the harvesting and chipping of logging residues. It is the aim of this research to apply existing Finnish know-how in regards to wood fuel harvesting in order to develop and investigate the price level of sustainable and local wood fuel supply chains.To determine the most suitable supply chain for forest fuels, various research methods were applied. An estimation of the forest resources in the Wick area was the first step of the research. The different cost components of the supply chain such as cutting, forwarding and chipping were then calculated based on Finnish experiences and adapted to conditions in Northern Scotland. Detailed transportation distance calculations and cost of transportation were calculated using GIS tools.Of the various supply chain designs considered, chipping at the landing seems to be the most suitable option. Chipping the roundwood at a central terminal would also be feasible; however, a suitable site would have to be identified since chipping of the material at the heating plant is not an option. Calculations indicate that forest chips can be delivered starting from approximately 20 € MWh−1 within a 50 km transportation distance when chipping is at roadside. If the transportation distance is 100 km wood chips could be delivered at approximately 23 € MWh−1. Results from the GIS analysis indicate that a sufficient supply of raw material will be available in the future. According to these calculations forest fuels can be a competitive energy source for heat and electricity production in Northern Scotland. 相似文献