Random induced subgraphs of Cayley graphs induced by transpositions

In this paper we study random induced subgraphs of Cayley graphs of the symmetric group induced by an arbitrary minimal generating set of transpositions. A random induced subgraph of this Cayley graph is obtained by selecting permutations with independent probability, $\lambda_n$. Our main result is that for any minimal generating set of transpositions, for probabilities $\lambda_n=\frac{1+\epsilon_n}{n-1}$ where $n^{-{1/3}+\delta}\le \epsilon_n0$, a random induced subgraph has a.s. a unique largest component of size $\wp(\epsilon_n)\frac{1+\epsilon_n}{n-1}n!$, where $\wp(\epsilon_n)$ is the survival probability of a specific branching process.Comment: 18 pages, 1 figur

Interest Group Size Dynamics and Policymaking (extensive revised version of WP 01-03)

We present a dynamic model of endogenous interest group sizes and policymaking. The model integrates `top-down' (policy) and `bottom-up' (individual and social-structural) influences on the development of interest groups. Comparative statics results show that the standard assumption of fixed-sized interest groups can be misleading. Furthermore, dynamic analysis of the model demonstrates that reliance on equilibrium results can also be misleading since equilibria may be unstable. Complicated dynamics may then emerge naturally, leading to erratic time patterns for policy and interest group sizes. Our model can endogenously generate the types of spurts and declines in organizational density reported in empirical studies.

On the relation between surface waves on a bubble and the subharmonic combination-frequency emission

The characterisation of bubbles using a two-frequency excitation technique is known to accurately detect and size certain bubble samples. This is done through the generation of a signal at Wi ± Wp/2 when the bubble is insonified by a fixed MHz imaging signal Wi and a variable pumping frequency, Wp , tuned to the bubble's resonance. Recent work has suggested that the principal mechanism for the generation of the Wi ± Wp /2 signal is linked to the onset of surface waves on the bubble's surface This paper strengthens this argument through the comparison of published experimentally measured thresholds for the Wi ±Wp /2 signal with recent theoretical models which predict the driving sound field pressure amplitudes required for the onset of surface waves on a spherical surface

Preparation and Characterization of Acid-induced Gels at pH 1.0-4.0 and Thermal-stable Dispersions at pH 5.5-6.0 using Preheated Whey Protein

Whey protein (WP) is a good source for producing protein-rich products, including satiety foods and beverages. Thermal aggregation of WP during sterilization or pasteurization impacts food quality important to shelf-stable beverages. Preheating WP improves the thermal stability at neutral acidity, and forming complexes with other molecules to provide charge and/or steric hindrance can be used to improve thermal stability of WP at acidic conditions. Conversely, aggregation properties of preheated WP upon acidification can be used to create unique functional properties. Therefore, studying properties of preheated WP can broaden its application in the food industry. Gelation of preheated WP and pectin mixtures at gastric acidity (pH 1.0-4.0) was studied in the first part of this thesis because of the potential to control satiety. The fast-acidified gels had less homogenous microstructures and lower strengths than gels slowly-acidified by glucono-delta-lactone. Preheated WP gelled at pH 3.5-4.0, while the WP-pectin mixture at mass ratios of 20:1, 10:1 and 5:1 formed gels at pH 2.0-3.5, 1.5-3.0 and 1.5-2.5, respectively. WP-pectin gels were weakened by NaCl but strengthened by CaCl2, indicating the significance of electrostatic attraction on gelation. Without hydrophobic attraction and hydrogen bonds, gelation was not observed for preheated WP but was evident for the WP-pectin mixtures at pH 2.5 and 3.0. The findings suggest the potential application of preheated WP-pectin mixtures to increase the viscosity in the stomach. The second part of this thesis research was focused on combining sodium stearoyl lactylate (SSL) and preheating treatment to improve thermal stability of WP at pH 5.5-6.0. The binding between SSL and WP was promoted by heating based on particle size and zeta-potential results. Circular dichroism spectroscopy indicated the formation of a more ordered secondary structure of WP after binding with SSL. SSL increased the zeta-potential magnitude, reduced the extent of denaturation, the exposure of sulfhydryl groups, and surface hydrophobicity of WP. These properties in turn improved the thermal stability of WP to make it possible to produce transparent fluids containing 4.5% WP and 0.2% SSL at pH 5.5-6.0

ARFBF MODEL FOR NON STATIONARY RANDOM FIELDS AND APPLICATION IN HRTEM IMAGES

International audienceThis paper presents a new model called Autoregressive Fractional Brownian Field (ARFBF) for analyzing textures which contain stationary and non-stationary components. The paper also proposes two estimation methods for the parameter of an isotropic fractional Brownian field based on Wavelet Packet (WP) spectrum: the Log-Regression on Diagonal WP spectrum (Log-RDWP) and the Log-Regression on Polar representation of WP spectrum (Log-RPWP). The Log-RPWP method provides a better estimation performance for small size images. We show the interest of ARFBF model and Log-RPWP for characterizing High-Resolution Transmission Electron Microscopy (HRTEM) images

Validation of written and video based assessment instruments in physical education

A written paper (WP) and a video-based-paper (VP) were used to measure the learning outcomes of three experimental teaching units (ETUs) of athletics. The subjects (n=49) were 16 year olds. The ETUs represented three teaching environments; practice, practice and handouts, and classbased sessions. Pre and post-tests were administered for the content of rules, planning tactics and techniques. Rasch model analysis showed that both tests were unidimensional and reliable (R ranged from 0.86 to 0.92). The efficiency of the three experimental teaching units was evaluated by means of paired sample t-tests. The subjects performed better on the posttests (WP: effect size=1.2 and VP: effect size=0.93). The pre-tests and posttests abilities of the subjects were highly correlated (WP: r=0.380 and VP: r=0.322). The subjects of the class-based sessions achieved significantly better scores on all content areas when video based assessments were used. The findings of this study are applicable to athletics.peer-reviewe

Highlights of NASA/DOE photovoltaic market assessment visit to Morocco

A broad range of agricultural, rural development, and other power applications in various regions of Morocco were examined to determine the potential market for photovoltaic products in Moroccan development. The primary focus of the study was the agriculture sector which accounts for approximately 17% of the country's GNP. The country has a clear need for reliable remote power systems, but does not have the financial resources to invest in the relatively high capital cost PV equipment. A modest potential for PV use was identified in nonagricultural rural services, such as refrigerators for rural clinics and rural radio-telephones. The main potential for PV in Morocco in the next five years lies mainly in the telecommunications sector. Applications include rural TV sets, TV repeater stations, microwave relay stations, and railroad, marine, and airline signalling. Market size estimates were derived from development and expansion plans. At an average customer cost for complete installed systems from $18/Wp to$30/Wp the total potential market value is estimated in the range of $6.6 to$11 million over the 1981-1986 period

Waste paper and macroalgae co-digestion effect on methane production

The present study investigates the effect on methane production from waste paper when co-digested with macroalgal biomass. Both feedstocks were previously mechanically pretreated to reduce their particle size. The study was planned according two factors: the feedstock to inoculum (F/I) ratio and the waste paper to macroalgae (WP/MA) ratio. The F/I ratios checked were 0.2, 0.3 and 0.4 and the WP/MA ratios were 0:100, 25:75, 50:50, 75:25 and 100:0. The highest methane yield (386 L kg−1 VSadded) was achieved at an F/I ratio of 0.2 and a WP/MA ratio of 50:50. A biodegradability index of 0.87 obtained in this study indicates complete conversion of feedstock at an optimum C/N ratio of 26. Synergistic effect was found for WP/MA 25:75, 50:50 and 75:25 mixing ratios compared with the substrates mono-digestion