942 research outputs found
Walking track analysis: an assessment method for functional recovery after sciatic nerve injury in the rat
Walking track analysis was first described by de Medinaceli et al. This technique
has been significantly modified to provide methods of indexing nerve
function that are more valid. Moreover, it has been questioned by several authors.
The aim of the present review is to offer a combined knowledge about
walking track analysis for scientists who deal with neuroscience
Use of Phosphoric Acid and Furfuryl Alcohol for Soil Stabilization
This paper presents results of an investigation of the effects of phosphoric acid and furfuryl alcohol on the resistance and strengths of a clayey soil and of a sandy soil. Results indicate that greater water resistance and higher strengths can be obtained with both soils by using the admixtures. For the sandy soil, a certain optimum amount of phosphoric acid gives the maximum strengths for all furfuryl alcohol contents. The stabilization mechanism for the clayey soil is thought to be a combination of the formation of phosphoric gels and of a resin product of a furfuryl alcohol polymerization reaction. The mechanism for the sandy soil is the formation of the polymerization resin product
Volumetric and three-dimensional examination of sella turcica by cone-beam computed tomography: reference data for guidance to pathologic pituitary morphology
Background: The aim of the study was to assess the dimensions and volume of sella turcica in healthy Caucasian adults with normal occlusion and facial appearance from cone-beam computed tomography (CBCT) images.
Materials and methods: CBCT images of 80 Caucasian adult patients (40 males, 40 females) with normal facial appearance and occlusion taken previously for diagnostic purposes were evaluated. Two groups were constructed in accordance to gender. The volume, length, diameter, and depth of the sella turcica were measured by Romexis software programme. Mann-Whitney U test and Independent t-tests were used for statistical analysis.
Results: The mean lengths of the sella were 9.9 mm and 10.2 mm, depths were 9.2 mm and 8.8 mm and diameters were 12.3 mm and 12.1 mm in female and male groups, respectively. Between the genders, no statistically significant differences were found for any of the measurements. There were significantly higher values for the volume of sella turcica in males than in females (1102 ± 285.3 mm3 and 951.3 ± 278.5 mm3, respectively).
Conclusions: The dimensions of sella turcica in healthy Caucasian adults with normal occlusion and facial appearance revealed nonsignificant differences between the genders. Individual variability in dimensions and gender differences in the volume are of importance in comparison of patients with craniofacial syndromes and aberrations. Knowledge concerning the dimensions and volume of sella turcica will be clinically relevant for a guidance to consciously realize pituitary disorders
Supplier quality improvement: the value of information under uncertainty
We consider supplier development decisions for prime manufacturers with extensive supply bases producing complex, highly engineered products. We propose a novel modelling approach to support supply chain managers decide the optimal level of investment to improve quality performance under uncertainty. We develop a Poisson–Gamma model within a Bayesian framework, representing both the epistemic and aleatory uncertainties in non-conformance rates. Estimates are obtained to value a supplier quality improvement activity and assess if it is worth gaining more information to reduce epistemic uncertainty. The theoretical properties of our model provide new insights about the relationship between the degree of epistemic uncertainty, the effectiveness of development programmes, and the levels of investment. We find that the optimal level of investment does not have a monotonic relationship with the rate of effectiveness. If investment is deferred until epistemic uncertainty is removed then the expected optimal investment monotonically decreases as prior variance increases but only if the prior mean is above a critical threshold. We develop methods to facilitate practical application of the model to industrial decisions by a) enabling use of the model with typical data available to major companies and b) developing computationally efficient approximations that can be implemented easily. Application to a real industry context illustrates the use of the model to support practical planning decisions to learn more about supplier quality and to invest in improving supplier capability
Simple Functors of Admissible Linear Categories
Generalizing an idea used by Bouc, Thévenaz, Webb and others, we introduce the notion of an admissible R-linear category for a commutative unital ring R. Given an R-linear category (Formula presented.) , we define an (Formula presented.) -functor to be a functor from (Formula presented.) to the category of R-modules. In the case where (Formula presented.) is admissible, we establish a bijective correspondence between the isomorphism classes of simple functors and the equivalence classes of pairs (G, V) where G is an object and V is a module of a certain quotient of the endomorphism algebra of G. Here, two pairs (F, U) and (G, V) are equivalent provided there exists an isomorphism F ← G effecting transport to U from V. We apply this to the category of finite abelian p-groups and to a class of subcategories of the biset category. © 2015, Springer Science+Business Media Dordrecht
Soil Stabilization with Polystyrene
This paper presents results of an investigation of the effect of polystyrene on the engineering properties of three soils. Use of a polystyrene-benzene solution as an admixture resulted in increased strength values. Satisfactory resistance to expansion and frost action was obtained with sandy and silty soils; unsatisfactory results were obtained with a clayey soil. Polystyrene stabilization is most effective with sandy soils; effectiveness decreases with increasing clay content. At present the method does not compare favorably with the economics of other available methods of stabilization
Expansion of Montimorillonite Due to Adsorption of Water Vapor
Expansions of pure sodium and calcium montmorillonites due to absorption of water vapor were studied and the results were correlated with X-ray diffraction and free swelling studies. Specimens of various porosities were used. Results indicate that the uptake of water is a multimolecular physical adsorption phenomenon which justifies application of BET theory. Porosity of specimens did not appreciably affect their expansions due to adsorption of water vapor. Sodium montmorillonite expanded appreciably more than calcium montmorillonite. At near saturation vapor pressure, calcium montmorillonite has attained practically its maximum swelling, while sodium montmorillonite will expand further if exposed to liquid water. Free energies of wetting, calculated from adsorption isotherm data, do not directly reflect the extent of swelling but do reflect the uplift pressures developed. Sodium montmorillonite presents the more serious problem with respect to settlement, and calcium montmorillonite presents the more serious problem with respect to uplift pressures
Revealing instabilities in a generalized triadic supply network: a bifurcation analysis
Supply networks are exposed to instabilities and thus a high level of risk. To mitigate this risk, it is necessary to understand how instabilities are formed in supply networks. In this paper, we focus on instabilities in
inventory dynamics that develop due to the topology of the supply network. To be able to capture these topology-induced instabilities, we use a method called generalized modeling, a minimally specified modeling approach adopted from ecology. This method maps the functional dependencies of production rates on the inventory levels of different parts and products, which are imposed by the network topology, to a set of elasticity parameters. We perform a bifurcation analysis to investigate how these elasticities affect the stability. First, we show that dyads and serial supply chains are immune to topology-induced instabilities. In contrast, in a simple triadic network, where a supplier acts as both a first and a second tier supplier, we can identify instabilities that emerge from saddle-node, Hopf, and global homoclinic bifurcations. These bifurcations lead to different types of dynamical behavior, including exponential convergence to and divergence from a steady state, temporary oscillations around a steady state, and co-existence of different types of dynamics, depending on initial conditions. Finally, we discuss managerial implications of the results
Notes on Determination of Carbonates in Soils by Chemical Means, D.T. A., and X-Ray
Various methods for measurement of carbonates in soils were tried and studied. Gas evolution methods are accurate but slow and susceptible to experimental error. Acid neutralization is rapid and offers a fair approximation, but it is affected by many non-carbonate minerals. Versenate methods are rapid and accurate, but are affected by exchangeable calcium on the clay. None of these methods is ordinarily specific for calcite or dolomite. Differential thermal analysis is accurate and specific for calcite or dolomite. Best results were obtained by measuring peak height after runs in an air atmosphere. However, analyses are slow and are influenced by changes in the apparatus. X-ray diffraction from a copper tube is accurate if peak area rather than peak height is measured, but the intensities are sensitive to the presence of iron, which absorbs most of the X-rays. X-ray fluorescence measurement of calcium Kα radiation is accurate and less susceptible to variable absorption, but since this method is affected by non-carbonate calcium, correction by leaching and re-testing is suggested. This appears to be the method most worthy of further examination
A method for volume stabilization of single, dye-doped water microdroplets with femtoliter resolution
A self-control mechanism that stabilizes the size of Rhodamine B-doped water
microdroplets standing on a superhydrophobic surface is demonstrated. The
mechanism relies on the interplay between the condensation rate that was kept
constant and evaporation rate induced by laser excitation which critically
depends on the size of the microdroplets. The radii of individual water
microdroplets (>5 um) stayed within a few nanometers during long time periods
(up to 455 seconds). By blocking the laser excitation for 500 msec, the stable
volume of individual microdroplets was shown to change stepwise.Comment: to appear in the J. Op. Soc. Am.
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