Does greater product information actually inform consumer decisions? The relationship between product information quantity and diversity of consumer decisions

For many consumer goods, the advent of online markets dramatically increases the amount of information available about products’ different features and qualities. Although numerous studies have investigated the effects of information quantity on individual-level decisions, it is still unknown how the amount of attribute information affects group-level patterns of behavior, particularly when consumers are also aware of a choice’s popularity. In the present studies, we hypothesized that when attribute information increases, it may exceed the individual’s cognitive capacity to process this information, and as a result conformity - choosing the most popular item - becomes more likely. In this study, we first examined empirical data collected from human subject experiments in a simulated online shopping experience, and then developed an agent-based model (ABM) to explore this behavioral clustering. Both studies confirmed our primary hypotheses, and the ABM shows promise as a tool for exploring extensions of these ideas.     

Advising,gender, and performance: Evidence from a university with exogenous adviser–student gender match

This paper provides the first causal evidence on the effects of gender match in the adviser–student relationship (as opposed to the well-researched instructor–student relationship) on student outcomes along both the intensive and extensive margins. We analyze administrative data from a university with a faculty adviser assignment policy that makes gender pairing between advisers and students exogenous. We find that matching female students with female adviser has a positive and significant effect on retention and grade point average (GPA) upon graduation, particularly for students with academic challenges and non-science, technology, engineering, and mathematics students. For female students with below-median high school GPA, gender match is found to raise the odds of graduate school enrollments.     

Small grid drawings of planar graphs with balanced partition

In a grid drawing of a planar graph, every vertex is located at a grid point, and every edge is drawn as a straight-line segment without any edge-intersection. It is known that every planar graph G of n vertices has a grid drawing on an (n?2)×(n?2) or (4n/3)×(2n/3) integer grid. In this paper we show that if a planar graph G has a balanced partition then G has a grid drawing with small grid area. More precisely, if a separation pair bipartitions G into two edge-disjoint subgraphs G ₁ and?G ₂, then G has a max?{n ₁,n ₂}×max?{n ₁,n ₂} grid drawing, where n ₁ and n ₂ are the numbers of vertices in G ₁ and?G ₂, respectively. In particular, we show that every series-parallel graph G has a (2n/3)×(2n/3) grid drawing and a grid drawing with area smaller than 0.3941n ² (<(2/3)² n ²).     

Settling-site selection and survival of two scale insects,Ceroplastes rubens andC. ceriferus, on citrus trees

Summary We studied settling-site selection and the resulting survival of two sessile scale insects,Ceroplastes rubens andC. ceriferus, in the citrus tree,Citrus unshiu, in central Japan. C. rubens preferred 0-year-old twigs most as a settling-site; the density of nymphs settling on 0-year-old twigs was significantly higher than those on ≥1-year-old twigs, and few nymphs settled on ≥3-year-old twigs. The mean survival rates from settling until reproduction in the next year were significantly higher on more preferred twigs than on less preferred ones. InC. ceriferus, nymphs significantly preferred 1- and 2-year-old twigs to 0- and ≥3-year-old ones, and the mean survival rates on the more preferred 1- and 2-year-old twigs were significantly higher than those on less preferred ≥3-year-old twigs. However, the survival rate on less preferred 0-year-old twigs was slightly higher than those on 1- and 2-year-old ones. Thus, in both species of scale, it was the preferred twigs which were more profitable sites for survival after settling, except for less preferred 0-year-old twigs forC. ceriferus. In both scale species, most mortality was due to growth cessation, which is believed to be related to the twig quality as a food source. Predators and parasitoids were minor mortality factors. Both species showed constant survival rates until the density of settled nymphs exceeded double the “upper-limit” density, whereupon they decreased drastically. Nymphs ofC. rubens settling on twigs of high scale density showed a spacing-out distribution, those ofC. ceriferus did not. InC. rubens, an increase in preference for originally less profitable twigs at the later stage of the settling season was observed, but not inC. ceriferus. Accordingly, individuals ofC. rubens showed a stronger tendency to avoid conspecifics than didC. ceriferus. Although nymphs of the two scales clearly preferred more profitable sites, their settling-site selection did not agree with the predictions from the ideal free distribution theory (Fretwell and Lucas, 1970). The discrepancies were (1) frequent settling on less profitable sites at the early stage of the settling season, (2) insufficient utilization of the most profitable twigs, and (3) virtually 100% mortality on overcrowded twigs under conditions where unoccupied profitable twigs still remained. These discrepancies are thought due to the limited dispersal time of nymphs. Contribution to the ecological studies of scale insects 2.     

Survival rate and sex ratio in habu,Trimeresurus flavoviridis (Viperidae), on the subtropical Okinawa Island, Japan

We examined the age structure and sex ratio of a viperid snake,Trimeresurus flavoviridis, based on samples collected by hand by local inhabitants, habu hunters and by baited traps in the middle and south of Okinawa Island, Japan. Small individuals had a low possibility of capture in all the collecting methods. The age structure was estimated through summing up the age frequency in each snout-vent length (SVL) class in samples with a similar SVL structure. From the age structures, annual survival rates of adult females and males were estimated to be 0.7 and 0.8, respectively. In most samples the sex ratio was biased towards males, especially in March and August and in large individuals. However, the female proportion increased in June.     

Body mass changes inTrimeresurus flavoviridis (Viperidae) on Okinawa Island, Japan

Body masses of wild-caught habu,Trimeresurus flavoviridis, were measured with known error range. Habu larger than mature female size had steeper slope in length-mass regression than smaller individuals. Females outweighed males in most snout-ventlength classes and in early summer. Gravid females outweighed non-gravid ones by about 20% on the average, but the body mass ranges of the two groups overlapped. Through the body mass change in mature females, the proportion of gravid females was estimated to be about 0.5.     

Generalization of Fisher's z-transformation

We deal with the asymptotic expansions of the means and the variances of the correlation coefficients in truncated bivariate normal populations. The Fisher's z-transformation is generalized for stabilizing variance in a truncated normal population. The Hermite moments are introduced, and the relationship among cross moments, central cross moments, and Hermite moments are discussed.     

Effects of dutasteride on lower urinary tract symptoms: a prospective analysis based on changes in testosterone/dihydrotestosterone levels and total prostatic volume reduction

This study analyzed the effects of dutasteride on lower urinary tract symptoms based on the association between changes in the total testosterone (TT)/dihydrotestosterone (DHT) levels and total prostate volume (TPV) reduction. Sixty participants diagnosed with benign prostatic hyperplasia were given 0.5?mg of dutasteride daily for 52 weeks. Measures of TT and DHT levels, TPV and uroflowmetry were obtained before and after dutasteride treatment. Forty-three patients demonstrated a TPV reduction of ≥5% (Group 1), whereas the remaining 17 patients demonstrated a TPV reduction of <5% (Group 2). DHT suppression and DHT/TT ratio at baseline were significantly higher in Group 1 than Group 2. International Prostate Symptom Scores (IPSS) and uroflowmetry were significantly improved in both groups. In Group 2, nine patients demonstrated some improvement in IPSS (Group 2A), whereas eight did not (Group 2B). The rate of TT increase and improvement in voiding symptoms were significantly higher in Group 2A than Group 2B. Dutasteride-induced TPV reduction is dependent on individual 5-α reductase inhibitor activity. Some patients demonstrating smaller dutasteride-induced TPV reduction may experience an improvement in voiding symptoms owing to an increased level of testosterone.     

Portfolio Inertia and Epsilon-Contaminations

This article analyzes investors’ portfolio selection problems in a two-period dynamic model of Knightian uncertainty. We account for the existence of portfolio inertia in this two-period framework. Furthermore, by incorporating investors’ updating behavior, we analyze how observing new information in the first period will affect investors’ behavior. By this analysis, we show that observing new information in the first period will expand portfolio inertia in the second period compared with the case in which observing new information has not been gained in the first period if the degree of Knightian uncertainty is sufficiently large.     

Yoga stretching for improving salivary immune function and mental stress in middle-aged and older adults

Protection against age-related immune suppression is important in elderly individuals. This study determined the effect of yoga on mucosal immune function and mental stress. Saliva samples were collected from 23 adult women (age: 60.4 ± 10.4 years) before and after 90 minutes of yoga stretching or rest to measure secretory immunoglobulin A (SIgA), cortisol, and testosterone. The SIgA concentration and secretion rate were significantly higher after yoga than before (p < .05). The cortisol concentration and secretion rate were lower and testosterone secretion rate higher after yoga (p < .05). Yoga stretching can reduce stress and enhance mucosal immune function in elderly women.