Teaching Note—Integrating Theory and Research Methods in a First-Year Doctoral Sequence or Program

This teaching note describes an innovative process in which faculty members worked collaboratively to create an integrated three-course sequence of requisite course content in a PhD program, developed complementary assignments, and coordinated a classroom experience that led to the creation of an individualized area statement and eventual integrated literature review. Lessons learned from this experience are discussed.     

BAYESIAN BETA REGRESSION: APPLICATIONS TO HOUSEHOLD EXPENDITURE DATA AND GENETIC DISTANCE BETWEEN FOOT-AND-MOUTH DISEASE VIRUSES

There is considerable interest in understanding how factors such as time and geographic distance between isolates might influence the evolutionary direction of foot‐and‐mouth disease. Genetic differences between viruses can be measured as the proportion of nucleotides that differ for a given sequence or gene. We present a Bayesian hierarchical regression model for the statistical analysis of continuous data with sample space restricted to the interval (0, 1). The data are modelled using beta distributions with means that depend on covariates through a link function. We discuss methodology for: (i) the incorporation of informative prior information into an analysis; (ii) fitting the model using Markov chain Monte Carlo sampling; (iii) model selection using Bayes factors; and (iv) semiparametric beta regression using penalized splines. The model was applied to two different datasets.     

The resilient frugivorous fauna of an urban forest fragment and its potential role in vegetation enrichment

Urban Ecosystems - Anthropocentric defaunation affects critical ecological processes, such as seed dispersal, putting ecosystems and biomes at risk, and leading to habitat impoverishment. Diverse...     

Reallocation of pronouns through contact: In‐the‐moment identity construction amongst Southern California Salvadorans

This study uses natural, everyday social interaction within Salvadoran families living in Southern California to examine the use of the 2nd‐person singular pronouns tú and vos (and their corresponding morphologies) in this contact variety of Spanish. An in‐depth, qualitative analysis reveals that the employment and significance of these forms of address do not conform entirely to Salvadoran norms, nor to those of the surrounding Mexican‐based Spanish koiné. Accommodation to the pronominal repertoire of the region's majority serves as a communicative resource driven by questions of U.S./Los Angeles identity and solidarity with speakers in‐the‐moment interlocutor(s), a process which has caused the original Salvadoran pronouns to also be reallocated and refunctionalized (Britain and Trudgill 1999 ) as resources for accomplishing Salvadoran identity. Members of this community make active use of their pronominal options in real‐time interaction as they navigate the fluid, multifaceted identities that they and their interlocutors now embody in the U.S. context.     

Urbanization homogenizes the interactions of plant-frugivore bird networks

Urban Ecosystems - Anthropogenic activities are the main cause of habitat loss and fragmentation, which directly affects biodiversity. Disruption in landscape connectivity among populations may...     

Comparing Objective and Subjective Bayes Factors for the Two-Sample Comparison: The Classification Theorem in Action

Many Bayes factors have been proposed for comparing population means in two-sample (independent samples) studies. Recently, Wang and Liu presented an “objective” Bayes factor (BF) as an alternative to a “subjective” one presented by Gönen et al. Their report was evidently intended to show the superiority of their BF based on “undesirable behavior” of the latter. A wonderful aspect of Bayesian models is that they provide an opportunity to “lay all cards on the table.” What distinguishes the various BFs in the two-sample problem is the choice of priors (cards) for the model parameters. This article discusses desiderata of BFs that have been proposed, and proposes a new criterion to compare BFs, no matter whether subjectively or objectively determined. A BF may be preferred if it correctly classifies the data as coming from the correct model most often. The criterion is based on a famous result in classification theory to minimize the total probability of misclassification. This criterion is objective, easily verified by simulation, shows clearly the effects (positive or negative) of assuming particular priors, provides new insights into the appropriateness of BFs in general, and provides a new answer to the question, “Which BF is best?”     

ISOLATED IN A TECHNOLOGICALLY CONNECTED WORLD?: Changes in the Core Professional Ties of Female Researchers in Ghana,Kenya, and Kerala,India

Using panel data gathered across two waves (2001 and 2005) from researchers in Ghana, Kenya, and Kerala, India, we examine three questions: (1) To what extent do gender differences exist in the core professional networks of scientists in low‐income areas? (2) How do gender differences shift over time? (3) Does use of information and communication technologies (ICTs) mediate the relationship between gender and core network composition? Our results indicate that over a period marked by dramatic increases in access to and use of various ICTs, the composition and size of female researchers core professional ties have either not changed significantly or have changed in an unexpected direction. Indeed, the size of women's ties are retracting over time rather than expanding.     

Horizontal plane sound source localization and auditory enhancement

Accurate sound source localization has advantages for the performance of work by humans. The ability to accurately localize sound sources contributes to perception, decision making and task performance. Two studies were conducted to investigate the prevalence of accurate sound source localization and the enhancement that spatially separated sound source locations can have on speech perception. The first study was conducted to characterize the ability to detect the location of horizontal plane sound sources. A sample of 117 participants with the hearing capacity within the normal limits participated in the study. The results indicated that sound sources located towards the front of the participant were identified more frequently than those sound sources located towards the rear positions. Based on the results found in the first study, a second study was conducted to assess performance within a listening task. Three different spatial configurations were used to assess if similar trends in performance translated to sound sources through headphones. Fifteen research participants performed a Coordinated Response Measure (CRM) task requiring the identification of a speech phrase and its associated information for a diotic configuration and two different spatial sound source configurations. Performance measured for the diotic configuration was significantly (p(0.05) less than for the two spatial configurations. The current studies indicate distinct advantages of utilizing localized sound sources to present auditory signal and speech to listeners.