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41.
This paper investigates matrix debonding from filler particles as a mechanism for weakening of a filled polymer. We analyze several simplified models of debonding. Our main concern is its effect on the overall elastic instants; for each debonding model, we calculate the change ΔW in overall strain energy density due to debonding. The resulting formulas for ΔW are all special cases of one general expression. Accordingly, we propose that this expression describes a broad class of debonding models, including some for which a detailed stress and strain analysis is not possible. 相似文献
42.
Stan De Spiegelaere Guy Van Gyes Hans De Witte Wendy Niesen Geert Van Hootegem 《Creativity & Innovation Management》2014,23(3):318-330
European policy is focusing on innovation as a way out of the economic crisis. At the same time, job insecurity is rising as Europe is still in crisis. In this paper, we examine whether job insecurity affects the innovative work behaviour of employees by focusing on the relation between job insecurity, job autonomy, work engagement and innovative work behaviour (IWB). Using employee level survey data, we use structural equation modelling to disentangle the relations between these variables. The partially mediated model shows the best fit with the data. This model shows that job insecurity and autonomy are both directly and indirectly, through work engagement, related with IWB. For autonomy these relations are positive, while they are negative (and smaller) for job insecurity. Moreover, a negative covariance is observed between job insecurity and autonomy. 相似文献
43.
44.
M. P. Murari R. Murari S. Parthasarathy C. A. Guy V. V. Kumar B. Malewicz Wolfgang J. Baumann 《Lipids》1990,25(10):606-612
Described is a reaction sequence for the total synthesis of lyso platelet activating factor (lysoPAF; 1-O-alkyl-sn-glycero-3-phosphocholine) and its enantiomer. The procedure is versatile and yields optically pure isomers of defined chain
length. The synthesis is equally suited for the preparation of lysoPAF analogues and its enantiomers with unsaturation in
the long aliphatic chain. First,rac-1(3)-O-alkylglycerol is prepared by alkylation ofrac-isopropylideneglycerol with alkyl methanesulfonate followed by acid-catalyzed removal of the ketal group. The primary hydroxy
group of alkylglycerol is then protected by tritylation, the secondary hydroxy group is acylated, and the protective trityl
group is removed under mild acidic conditions with boric acid on silicic acid, essentially without acyl migration. Condensation
of the diradylglycerol with bromoethyl dichlorophosphate in diethyl ether, hydrolysis of the resulting chloride, and nucleophilic
displacement of the bromine with trimethylamine givesrac-1-O-alkyl-2-acylglycero-3-phosphocholine in good overall yield. The racemic alkylacylglycerophosphocholine is finally treated
with snake venom phospholipase A2 (Ophiophagus hannah) which affords 1-O-alkyl-sn-glycero-3-phosphocholine (lysoPAF) of natural configuration in optically pure form. The “unnatural” 3-O-alkyl-2-O-acyl-sn-glycerol-1-phosphocholine enantiomer, which is not susceptible to phospholipase A2 cleavage, gives 3-O-alkyl-sn-glycero-1-phosphocholine upon deacylation with methanolic sodium hydroxide. Homogeneity and structure of the intermediates
and final products were ascertained by carbon-13 nuclear magnetic resonance spectroscopy on monomeric solutions. 相似文献
45.
Nocturnal intragastric feeding has been shown to be an effective means to improve clinical and biochemical features in glycogen
storage disease type I (GSD-I). In this study, we investigated the fatty acid patterns in a whole plasma and in circulating
lipoproteins in patients on this therapy. The results demonstrated massive concentration of total fatty acids coupled with
higher levels of triglycerides, free cholesterol, cholesterol ester and phospholipids. This hyperlipidemia involved all fatty
acids without distinction of carbon or bond numbers. However, the increase was more pronounced for saturated than polyunsaturated
fatty acids, as was demonstrated by the ratios of both oleic acid to linoleic acid (1.91±0.40 vs 0.80±0.09 in controls) and
of ω3+ω6 to ω9 fatty acid families (0.92±0.11 vs 1.66±0.08 in controls). The fatty acid patterns in very low (VLDL), low (LDL)
and high (HDL) density lipoprotein showed substantial differences in composition, reflecting an association between an abnormal
lipoprotein pattern and essential fatty acid deficiency. Furthermore, GSD-I patients exhibited a significant increase in VLDL
(17±2 vs 47±7 mg/dl) and LDL cholesterol (124±7 vs 206±24 mg/dl), coupled with a decrease in HDL cholesterol (49±4 vs 28±3
mg/dl). These data documenting high LDL cholesterol and low HDL cholesterol associated with an increased concentration and
proportion of saturated fatty acids suggest that GSD-I patients on nocturnal intragastric feeding are at high risk for atherosclerosis
and its complications. 相似文献
46.
Aurélien Plyer Guy Le Besnerais Frédéric Champagnat 《Journal of Real-Time Image Processing》2016,11(4):713-730
This paper deals with dense optical flow estimation from the perspective of the trade-off between quality of the estimated flow and computational cost which is required by real-world applications. We propose a fast and robust local method, denoted by eFOLKI, and describe its implementation on GPU. It leads to very high performance even on large image formats such as 4 K (3,840 × 2,160) resolution. In order to assess the interest of eFOLKI, we first present a comparative study with currently available GPU codes, including local and global methods, on a large set of data with ground truth. eFOLKI appears significantly faster while providing quite accurate and highly robust estimated flows. We then show, on four real-time video processing applications based on optical flow, that eFOLKI reaches the requirements both in terms of estimated flows quality and of processing rate. 相似文献
47.
Guy Jobbins Jack Kalpakian Abdelouahid Chriyaa Ahmed Legrouri El Houssine El Mzouri 《国际水资源开发杂志》2015,31(3):393-406
This article draws on three case studies of drip irrigation adoption in Morocco to consider the water–energy–food nexus concept from a bottom-up perspective. Findings indicate that small farmers' adoption of drip irrigation is conditional, that water and energy efficiency does not necessarily reduce overall consumption, and that adoption of drip irrigation (and policies supporting it) can create winners and losers. The article concludes that, although the water–energy–food WEF nexus concept may offer useful insights, its use in policy formulation should be tempered with caution. Technical options that appear beneficial at the conceptual level can have unintended consequences in practice, and policies focused on issues of scarcity and efficiency may exacerbate other dimensions of poverty and inequality. 相似文献
48.
In the service industry, workers perform work shifts and are assigned to interruptible activities and uninterruptible tasks during their shifts. The work shifts of regular employees are often established several weeks in advance of the operations when the activity and task demands are still uncertain. Just a few days before the operations when these demands are unveiled with more certainty, the planned schedules can be slightly modified and on-call temporary employees can be scheduled to satisfy the demands as best as possible. As acceptable modifications, extending the planned shifts and moving workers’ meal breaks are considered. In this paper, we are interested in the scheduling problem encountered in this second step, which also involves assigning activities and tasks to the scheduled work shifts. To produce good-quality solutions in fast computational times for large-sized instances, we develop a two-phase heuristic. In the first phase, an approximate mixed-integer programming model is used to suggest temporary shifts and extensions to regular shifts and to schedule and assign tasks. In the second phase, a column-generation heuristic embedded in a rolling horizon procedure determines the final shifts and assigns activities to them. Computational results obtained on randomly generated instances are reported to evaluate the validity of the proposed solution method. 相似文献
49.
The Sanaga River is one of Sub‐Saharan Africa's largest and greatly regulated rivers. Available flow data for this hydrosystem largely cover the pre‐ and post‐regulation periods. From comparisons between unregulated (hypothetical) and observed scenarios, it has been possible to separate and to quantify hydro‐climatic (groundwater + rainfall) change effects from anthropogenic impacts (especially dam‐related alterations). To appreciate shifts in the river regime, discontinuity detection tests and the IHA model were applied to discharge data series reflecting average and extreme flow conditions, respectively. Results obtained principally from the Hubert segmentation method reveal that a major discontinuity occurred in 1970–1971 separating a surplus phase between 1945–1946 and 1969–1970, and a deficient and much contrasted one, from 1971/1972. This implies that the Sanaga catchment is dominantly affected by hydro‐climatic changes. However, wide land cover/land use changes experienced here since 1988 have resulted in an increase in surface runoff. Additional quickflows linked to these changes may have partly compensated for the substantial decline in the dry season rainfall and groundwater inputs observed from this date. Although at the monthly scale, dam‐related impacts on average flows increase with stage of regulation, the seasonal variability of the river regime remains generally unaffected. A comparison of the IHA statistics, calculated from unregulated and observed streamflow data, show that hydrologic shifts occurring in maximum and minimum discharges are mostly significant from 1971/1972 and are mainly due to the action of dams. Minimum flows appear, however, widely impacted, thus reflecting the prime objective assigned to the existing reservoirs, constructed to supplement flows for hydroelectricity production during the dry season. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
50.
Gilhuly TJ Hutchings SR Dumont GA Macleod BA 《Computer methods and programs in biomedicine》2008,89(2):179-188
The neuromuscular blocker advisory system (NMBAS) is a computer program developed to provide advisory guidance to anesthesiologists on the timing and dose of rocuronium to paralyze patients during surgery. It is believed that the use of such a system will administer the minimally effective amount of drug, maintaining the patient in a state of paralysis that is useful for surgery yet easily reversible. This will improve patient safety and result in more efficient care. In this paper we present the NMBAS, its basic methodology, and its development though a pilot study. Novel methods of handling neuromuscular response data are presented, including relaxation measurement and the enhanced-train-of-four sensing modality. New methods of handling nonlinearities at the neuromuscular junction to allow application of adaptive control techniques are presented. A novel form of modelling combining model swapping and RLSE adaptation to accommodate the patient variation seen with NMB drugs is introduced. A pilot study testing the NMBAS was undergone to prepare the NMBAS for application in a full clinical trial, in which patients undergoing prostate brachytherapy surgeries using rocuronium for intubation were admitted. 相似文献