Effects of hydroperiod on metamorphosis in \u3ci\u3eRana sphenocephala\u3c/i\u3e

Hydroperiod, the time a temporary pond holds water, is an important factor influencing recruitment in amphibian populations and structuring amphibian communities. We conducted an experiment to test the effect of hydroperiod on metamorphic traits of the southern leopard frog (Rana sphenocephala), a common amphibian in the southeastern United States. We reared larval R. sphenocephala in artificial ponds at a density of 32 larvae per tank (initial volume = approximately 650 liter). We dried the tanks according to natural patterns, using three different hydroperiods (60, 75 and 90 d). Experimental hydroperiods had a significant effect on the number of metamorphs and the length of the larval period, but not on overall survival (larvae + metamorphs) nor size at metamorphosis. Our findings confirm a pattern observed in field studies and are similar to results of experimental investigations of closely related ranid frogs. Our results demonstrate that relatively small differences in hydroperiod length (i.e., as little as 15 d) may have large effects on juvenile recruitment in R. sphenocephala

Holistic Model of Website Design Elements that Influence Trustworthiness

Trustworthiness of a website relies foremost on a good first impression which includes the visitor’s perception of the user interface. The focus of this research is to investigate the effects of website design elements on user perception of trustworthiness of a site and provide a set of guidelines for website designers. The research design is based on Yosef Jabardeen’s (2009) “conceptual framework analysis”. In this research paper, a holistic model is developed to depict the relationships among website design elements and trustworthiness. The model was tested, validated and updated using the results of the repertory grid technique, a process that elicits perceptions about a topic from an individual. For this research, the topic was website trust, the objects were the website design elements, and the constructs were elicited perceptions regarding those website design elements. The repertory grid technique was applied in two stages to a set of participants made up of website users and website designers. Analysis yielded useful information regarding website design associations and correlations of perceptions. The research findings confirmed original suggestions regarding associations and produced an updated, validated model of website design elements. The research indicated that while all design elements had their importance regarding trust, those elements that provided for the function and security of the website rated the highest in importance and expectation. The validated model will aid website designers in understanding what elements are appealing to the visual senses and conjure credibility and trust. Most importantly, this new understanding may help designers to create websites that attract and retain new users and establishing a successful presence on the Internet

Does Resource Commercialization Induce Local Conservation? A Cautionary Tale From Southwestern Morocco

Ecotourism, bioprospecting and non-timber product marketing have been promoted recently as market-based instruments for environment protection, but without sound understanding of the resulting net conservation effects. We present evidence on the local conservation effects of recent argan oil commercialization in Morocco, which seems a promising case study in conservation through resource commercialization. Our empirical analysis shows, however, that resource commercialization is not creating strong net conservation incentives because assumptions implicit in the prevailing logic prove incorrect in this case. Generally, the experience of southwestern Morocco provides a cautionary tale about the assumed efficacy of conservation strategies founded on resource commercialization.Resource /Energy Economics and Policy,

ABC, 123: The Impact of a Mobile Phone Literacy Program on Educational Outcomes

CGD non-resident fellow Jenny Aker and co-authors report on the results from a randomized evaluation of a mobile phone education program (Project ABC) in Niger, in which adult students learned how to use mobile phones as part of a literacy and numeracy class. Overall, students demonstrated substantial improvements in literacy and numeracy test scores. There is also evidence of persistent impacts: six months after the end of the first year of classes, students in the program retained what they had learned better than others. The effects do not appear to be driven by differences in teacher quality or in teacher and student attendance. The results suggest that simple and relatively cheap information and communication technology can serve as an effective and sustainable learning tool for rural populations.Education

Carbon-carbon bond forming reactions of biomass derived aldehydes

The Knoevenagel reaction was applied to form a carbon-carbon double bond between the aldehydes (HMF, furfual) and an alpha di-carbonyl compound. The alpha di-carbonyl compound used was malonic acid, which can be bio-derived from glucose along fermentation routes. The effects of solvents (THF, water, ethanol, isopropanol, ethyl ether, toluene) and catalysts (e.g. homogeneous and heterogeneous amines, solid basic oxides) on the yields of alpha-beta unsaturated acids were investigated. It was found that the homogeneous amines worked well in THF solvent (90-100% conversion, 99% selectivity for furfural and HMF), while the poly(styrene) supported ethylenediamine gave a higher conversion and selectivity for HMF (65± 5%, 99% selectivity) over furfural (58 ± 7%, 99% selectivity). This trend was also present in competition reactions where both HMF and furfural were reacted in the same vessel. á-â Unsaturated mono-acids for both HMF and furfural were identified as minor side products. However, levulinic acid did not work as well under the conditions studied. Lastly, among the solvents studied, several caused precipitation of the Knoevenagel products.M.S.Committee Chair: Dr. Christopher Jones; Committee Co-Chair: Dr. Pradeep Agrawal; Committee Member: Dr. Sujit Banerjee; Committee Member: Dr. Tom Fulle

Combining Consumer Valuation Research with Sensory Science Techniques: A Laboratory Experiment

In this research, we integrated an experimental auction with sensory science techniques—namely, trained sensory panels used to analyze the sensory attributes of wines—to examine the effects of objective and sensory information in the market for California-produced Cabernet Sauvignons. The experiment permitted observation of consumer valuation for sensory attributes of wine, appellations, expert ratings, and wineries. Participants submitted bids each time they received new information about the wines. The balanced experimental design permits evaluation of the effects of consumer characteristics on attribute valuation. We had 236 people participate in the research, which consisted of nine rounds of bidding and one round of hedonic liking scores. Rounds 5-9 repeated the structure of information released in rounds 1-4, but added sensory information, yielding 472 observations for each type of information (e.g. appellation, expert rating, winery). We obtain a total of 8496 valuations, or bids and 944 hedonic “liking” ratings, as well as demographic information, wine consumption data, and a wine knowledge score for each consumer. The results of the research agree with many of the previously held notions about valuation of wine by consumers. Participants value Cabernet Sauvignons from Napa Valley and Sonoma County and their sub-appellations more than wines labeled with the California appellation. Bids for wines rated by experts such as the Wine Advocate (Robert Parker) or Wine Spectator increased as the experts’ ratings increased. However, we also find that consumer characteristics are very important in explaining WTP for wine attributes. The contributions of prestigious appellations to the value of Cabernet Sauvignons depended on consumer characteristics. Willingness to pay was highly correlated with sensory evaluation, but even after tasting the wine, appellation and expert ratings still mattered for WTP. Overall, the research describes a significant amount of heterogeneity in the preferences for sensory characteristics of wine, and that individual characteristics systematically explain many of the differences in valuation of wine attributes.Experimental Economics, Willingness to Pay, WTP, Wine, Consumer Valuation, Hedonic Pricing, Sensory Analysis, Demand and Price Analysis, Food Consumption/Nutrition/Food Safety, Marketing, Research Methods/ Statistical Methods,

Exploring the Relationship Between Drug and Alcohol Treatment Facilities and Violent and Property Crime: A Socioeconomic Contingent Relationship

Siting of drug and alcohol treatment facilities is often met with negative reactions because of the assumption that these facilities increase crime by attracting drug users (and possibly dealers) to an area. This assumption, however, rests on weak empirical footings that have not been subjected to strong empirical analyses. Using census block groups from Philadelphia, PA, it was found that the criminogenic impact of treatment facilities in and near a neighborhood on its violent and property crime rates may be contingent on the socioeconomic status (SES) of the neighborhood. Paying attention to both the density and proximity of facilities in and around neighborhoods, results showed that the criminogenic impact of treatment facilities depended largely on neighborhood SES. Under some conditions, more treatment facilities nearby were associated with lower crime. Reasons, why the presumed criminogenic impact of treatment facilities appears only under some conditions, were suggested

Policing a Negotiated World: A Partial Test of Klinger’s Ecological Theory of Policing

The primary goal of the current study is to examine a portion of Klinger’s theory. Specifically, we test the influence of organizational and environmental contextual factors, guided by Klinger’s theory, on one measure of officer vigor. To date, few studies have taken this approach to examine Klinger’s theory. The study builds on prior research that has tested aspects of Klinger’s theory and adds new analytic strategies that prior studies have not used. The results of this study have implications for both theory and practice, and they add to the growing literature examining the influence of ecological and organization factors on police behavior

Military Service and Offending Behaviors of Emerging Adults: A Conceptual Review

Focusing on the United States, this paper examines the impact of military service for the cohort of individuals that have experienced the social factors that characterize emerging adulthood as a unique stage in the life course. We argue that military service, as a turning point, may act differently in contemporary times compared to findings from past research. This difference is driven by changes in military service, the draft versus volunteer military service, and the prevalence of emerging adulthood. As a background, we describe emerging adulthood, examine how emerging adulthood relates to crime and deviance, explore the impact of military life on young adults, provide an overview of the demographics of military service, discuss the influence and outcomes of military life on young adults, and explore existing research linking military service and deviant and criminal behavior. We develop a theoretical model of the relationship between military service and emerging adulthood and explore the impact on criminological theory and policy