Direct mail selection by joint modeling of the probability and quantity of response

Operations such as integration or modularization of databases can be considered as operations on database universes. This paper describes some operations on database universes. Formally, a database universe is a special kind of table. It turns out that various operations on tables constitute interesting operations on database universes as well.

The Impact of Link Suggestions on User Navigation and User Perception

The study reported in this paper explores the effects of providing web users with link suggestions that are relevant to their tasks. Results indicate that link suggestions were positively received. Furthermore, users perceived sites with link suggestions as more usable and themselves as less disoriented. The average task execution time was significantly lower than in the control condition and users appeared to navigate in a more structured manner. Unexpectedly, men took more advantage from link suggestions than women

The Southern African Regional Science Initiative (SAFARI 2000) : wet season campaigns

The Southern African Regional Science Initiative (SAFARI 2000) involved two wet season and one dry season field campaigns. This paper reports on the wet season campaigns. The first was conducted at five sites along the Kalahari Transect in Zambia (Kataba Forest) and Botswana (Pandamatenga, Maun, Okwa River Crossing, Tshane) during February 2000 and concentrated primarily on characterizing the land surface with respect to exchanges of matter and energy with the atmosphere. The second, conducted in February 2001, focused on fluxes of water, gases and energy between the canopy and the atmosphere at Maun, Botswana, and at Skukuza in the Kruger National Park, South Africa. Eddy covariance measurements at Skukuza and Maun were designed to collect a near-continuous record of the seasonality and inter-annual variability in savanna carbon, water and energy exchanges in representative savanna ecosystems. This paper gives brief descriptions of the sites, the measurements made, and the methods used. It highlights some preliminary results, particularly from the first campaign, and outlines the next stages of the SAFARI 2000 projec

Simulations of elementary processes in entangle wormlike micelles under tension : a kinetic pathway to Y-junctions and shear induced structures

The merging process of two amphiphilic cylindrical micelles has been simulated using a coarse grained model in which amphiphiles are represented as chains of one head particle and four tail particles. In our set-up with twisted boundary conditions, a ring-shaped worm is effectively entangled with itself. Upon stretching the box, putting the worms under tension, a fusion into an H-like structure is observed, which eventually transforms into an almost tensionless structure with two freely gliding Y-junctions. The tensions on the worms never reach the point where scission becomes an alternative to fusion. We end with a short discussion of the possible implications of these observations

Clinically-evident tophi are associated with reduced muscle force in the foot and ankle in people with gout: a cross-sectional study

Background: The foot and ankle represent a common site for tophi in people with gout, yet it is unclear whether the presence of tophi is related to impaired muscle function. This study aimed to determine the association between foot and ankle tophi and muscle force in people with gout. Methods: Participants with gout were stratified into two groups based on the presence of clinically-evident tophi affecting the foot or ankle on physical examination. Isometric muscle force for plantarflexion, dorsiflexion, inversion and eversion was measured using static dynamometry. Mixed-models regression was used to determine the difference in muscle force between the two groups while adjusting for age, disease duration and foot pain. This model was also used to determine the difference in muscle force between presence and absence of tophi at specific locations within the foot and ankle. In addition, Pearson’s correlations were used to determine the association between total foot tophus count and muscle force. Results: Fifty-seven participants were included (22 with foot or ankle tophi and 35 without foot or ankle tophi). Foot and ankle tophi were most often seen at the Achilles tendon. After adjusting for age, disease duration and foot pain, participants with tophi had significantly reduced muscle force during plantarflexion (P < 0.001), dorsiflexion (P = 0.003), inversion (P = 0.003) and eversion (P = 0.001) when compared to participants without tophi. Those with Achilles tophi had significantly reduced force during plantarflexion (P < 0.001), inversion (P = 0.008) and eversion (P = 0.001). No significant differences in muscle force were observed between the presence and absence of tophi at other foot or ankle locations. There were also no significant correlations between total foot tophus count and muscle force (all P > 0.05). Conclusion: In people with gout, clinically-evident foot or ankle tophi are associated with muscle force deficits during foot plantarflexion, dorsiflexion, inversion and eversion, which persist despite adjusting for age, disease duration and foot pain. Tophi at the Achilles tendon, which associate with force deficits, may contribute to reduced muscular activation and consequent disuse muscle atrophy

A criterion for the number of factors

This note proposes a new criterion for the determination of the number of factors in an approximate static factor model. The criterion is strongly associated with the scree test and compares the differences between consecutive eigenvalues to a threshold. The size of the threshold is derived from a hyperbola and depends only on the sample size and the number of factors k. Monte Carlo simulations compare its properties with well-established estimators from the literature. Our criterion shows similar results as the standard implementations of these estimators, but is not prone to a lack of robustness against a too large a priori determined maximum number of factors kmax