Differentiation of unevaporated gasoline samples according to their brands, by SPME-GC-MS and multivariate statistical analysis

One of the aims of fire investigations is to identify associations among accelerants according to their source. In this study, 50 gasoline samples--representing five brands--were analyzed using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). Chemometric procedures, such as principal component analysis (PCA) and discriminant analysis (DA), were applied to a data matrix obtained by the target compound chromatogram method, to discriminate samples according to their brand. PCA was successful in finding a natural grouping of samples according to their brand, suggesting that aromatic compounds were more useful than aliphatics for the purpose of this study. DA, if applied to aromatic compounds, gave both a classification ability and a prediction ability of 100%. The outstanding results obtained by this work provide the basis of a data matrix that could be used in real cases of arson to link a sample of unevaporated gasoline to its brand or refinery.     

The metropolitan area of Monterrey in the year 2020

The author discusses possible future trends in economic development and urbanization in the city of Monterrey, Mexico. Information is provided on metropolitan growth from 1940 to 1995; population size and growth rate; extension of the urban area; deconcentration; and projections according to land use.     

Hegel's critique of liberalism and natural law: Reconstructing ethical life

This essay considers the evolution of Hegel's political and legal theory with respect to the emergence of a classical liberal society and modern natural law. I argue that Hegel abandoned his early concerns which focused on a revival of the Greek polis and ethics over legality and refocused his efforts at reaching a modern form of ethical life predicated on the acceptance of classical liberal society and modern natural law. I try to argue that Hegel wanted to achieve a present-day communal ethics without abolishing the modern individual subject endowed with rights. However, I seek to draw attention to Hegel's criticism of empirical individualism and social atomism.     

Using an Eye Tracking Device to Assess Vulnerabilities to Burglary

This research examines the extent to which visual cues influence a person’s decision to burglarize. Participants in this study (n?=?65) viewed ten houses through an eye tracking device and were asked whether or not they thought each house was vulnerable to burglary. The eye tracking device recorded where a person looked and for how long they looked (in milliseconds). Our findings showed that windows and doors were two of the most important visual stimuli. Results from our follow-up questionnaire revealed that stimuli such as fencing, beware of pet signs, cars in driveways, and alarm systems are also considered. There are a number of implications for future research and policy.     

Concurrent and Prospective Analyses of Peer, Television and Social Media Influences on Body Dissatisfaction, Eating Disorder Symptoms and Life Satisfaction in Adolescent Girls

The degree to which media contributes to body dissatisfaction, life satisfaction and eating disorder symptoms in teenage girls continues to be debated. The current study examines television, social media and peer competition influences on body dissatisfaction, eating disorder symptoms and life satisfaction in a sample of 237 mostly Hispanic girls. 101 of these girls were reassessed in a later 6-month follow-up. Neither television exposure to thin ideal media nor social media predicted negative outcomes either concurrently nor prospectively with the exception of a small concurrent correlation between social media use and life satisfaction. Social media use was found to contribute to later peer competition in prospective analysis, however, suggesting potential indirect but not direct effects on body related outcomes. Peer competition proved to be a moderate strong predictor of negative outcomes both concurrently and prospectively. It is concluded that the negative influences of social comparison are focused on peers rather than television or social media exposure.