The Diffusion of a Task Recommendation System to Facilitate Contributions to an Online Community

This paper studies the diffusion of SuggestBot, an intelligent task recommendation system that helps people find articles to edit in Wikipedia. We investigate factors that predict who adopts SuggestBot and its impact on adopters' future contributions to this online community. Analyzing records of participants' activities in Wikipedia, we found that both individual characteristics and social ties influence adoption. Specially, we found that highly involved contributors were more likely to adopt SuggestBot; interpersonal exposure to innovation, cohesion, and tie homophily all substantially increased the likelihood of adoption. However, connections to prominent, high‐status contributors did not influence adoption. Finally, although the SuggestBot innovation saw limited distribution, adopters made significantly more contributions to Wikipedia after adoption than nonadopter counterparts in the comparison group.     

Changes in the wavelength of unique yellow with retinal angle of incidence

The wavelength associated with the perception of unique yellow was determined for various retinal angles of stimulus incidence. Techniques previously used to measure the Stiles-Crawford (SCII) hue shift as a function of retinal angle of incidence were procedurally and instrumentally complex and, as a result, data from only two observers exist in the literature. A simpler technique is used here to obtain data from six observers, two of whom showed hue shift functions qualitatively different from those previously reported. The peak locations of the four typical SCII hue shift functions were found to correlate well with the peak locations of the π₄ and π₅ color mechanisms previously reported for the same observers. It is argued that peak location is the most valid indicator of the relationship between the Stiles-Crawford effects of the first (SCI) and second (SCII) kind and that common processes underlie the two effects.     

Professional involvement in the employment process.

The American Medical Association has recently decided to give a nod to collective bargaining to increase physicians' clout in dealing with managed care. The specter of pro-union organized medicine presents important questions and challenges for all health professionals. It is important to ask whether unionization holds promise for psychologists to assert professionalism and to protect patients in today's health care environment. The authors review the labor experience with unionization and collective bargaining in the nursing profession, to highlight possible lessons of their experience for psychology. Psychologists' experiences with unionizing at the state level are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Transgenic Arabidopsis lines expressing gene VI from cauliflower mosaic virus variants exhibit a range of symptom-like phenotypes and accumulate inclusion bodies

Gene VI of cauliflower mosaic virus (CaMV) is an important determinant of symptom expression during infection. We have constructed a series of transgenic Arabidopsis lines that express gene VI protein (P6) from two CaMV isolates (Bari-1 and Cabb B-JI) that cause mild and severe symptoms, respectively, in Arabidopsis, and from a recombinant virus (Baji-31) with a hybrid gene VI that causes very severe symptoms. From 41 transgenic lines analyzed, 17 showed symptom-like phenotypes that ranged from mild vein chlorosis to severe chlorosis and stunting. P6 levels in transgenic lines varied from undetectable in the lowest expressors to levels greater than those in CaMV-infected plants. There was a strong correlation between phenotype severity and the level of P6, and with the gene VI origin in the order, Baji-31 > B-JI > Bari-1. This was similar to symptom severity in Arabidopsis infected with the respective CaMV variant. We also found that transgenic P6 accumulated in inclusion bodies that were similar to those found in infected plants but lacking virions. We conclude that expression of P6, in the absence of virus replication, elicits a subset of the host symptom responses normally observed during infection and that the level, sequence, and possibly the form of P6 are important in potentiating the process.     

Psychiatric disorders and sexual risk among adolescents in mental health treatment.

Objective: To examine the relationship between psychiatric disorders and sexual behaviors among adolescents receiving mental health treatment. Adolescents in mental health treatment have been found to have higher rates of HIV risk behavior than their peers, but data concerning the relationship between psychopathology and risk are inconsistent and limited. Method: Eight hundred and forty adolescents (56% female, 58% African American, mean age = 14.9 years) and their parents completed computerized assessments of psychiatric symptoms via the Computerized Diagnostic Interview Schedule for Children (Shaffer, 2000a, 2000b). Adolescents also reported on sexual risk behaviors (vaginal/anal sex, condom use at last sex) and completed urine screens for a sexually transmitted infection (STI). Results: Adolescents meeting criteria for mania, externalizing disorders (oppositional defiant, conduct, and attention-deficit/hyperactivity disorders), or comorbid for externalizing and internalizing disorders (major depressive, generalized anxiety, and posttraumatic stress disorders) were significantly more likely to report a lifetime history of vaginal or anal sex than those who did not meet criteria for any psychiatric disorder (odds ratio [OR] = 2.0, 2.3, and 1.9, respectively). Adolescents meeting criteria for mania were significantly more likely to have 2 or more partners in the past 90 days (OR = 3.2) and to test positive for a STI (OR = 4.3) relative to adolescents who did not meet criteria for a psychiatric disorder. Conclusions: The presence of internalizing and externalizing disorders, especially mania, suggests the need for careful screening and targeting of adolescent sexual behavior during psychiatric treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Acetylcholinesterase inhibitors, neuropsychiatric symptoms, and Alzheimer's disease subtypes: An alternate hypothesis to global cognitive enhancement.

Cholinergic neurons are extensively implicated in cognitive functioning. Cholinergic deficiency is a widely accepted hypothesis of cognitive decline in Alzheimer's disease (AD) and is the impetus for the development of cholinesterase inhibitors (ChIs). Studies on the efficacy of ChIs emphasize global cognitive improvement and the amelioration of neuropsychiatric symptoms associated with AD. The authors propose that the current perception of ChIs as global cognitive enhancers may be misleading. It is hypothesized that these drugs improve cognition in specific AD subtypes primarily through psychotropic properties that facilitate attentional processing. In effect, increased attentional capacity through diminished neuropsychiatric symptoms serves to augment results on global cognitive measures: in particular, AD subtypes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)