Motivations for Social Media Use: Associations with Social Media Engagement and Body Satisfaction and Well-Being among Adolescents

Journal of Youth and Adolescence - Adolescents are spending considerable time on social media, yet it is unclear whether motivations for social media use drive different forms of social media...     

Hair analysis for delta(9)-THC,delta(9)-THC-COOH,CBN and CBD,by GC/MS-EI. Comparison with GC/MS-NCI for delta(9)-THC-COOH

A sensitive analytical method was developed for quantitative analysis of delta(9)-tetrahydrocannabinol (delta(9)-THC), 11-nor-delta(9)-tetrahydrocannabinol-carboxylic acid (delta(9)-THC-COOH), cannabinol (CBN) and cannabidiol (CBD) in human hair. The identification of delta(9)-THC-COOH in hair would document Cannabis use more effectively than the detection of parent drug (delta(9)-THC) which might have come from environmental exposure. Ketamine was added to hair samples as internal standard for CBN and CBD. Ketoprofen was added to hair samples as internal standard for the other compounds. Samples were hydrolyzed with beta-glucuronidase/arylsulfatase for 2h at 40 degrees C. After cooling, samples were extracted with a liquid-liquid extraction procedure (with chloroform/isopropyl alcohol, after alkalinization, and n-hexane/ethyl acetate, after acidification), which was developed in our laboratory. The extracts were analysed before and after derivatization with pentafluoropropionic anhydride (PFPA) and pentafluoropropanol (PFPOH) using a Hewlett Packard gas chromatographer/mass spectrometer detector, in electron impact mode (GC/MS-EI). Derivatized delta(9)-THC-COOH was also analysed using a Hewlett Packard gas chromatographer/mass spectrometer detector, in negative ion chemical ionization mode (GC/MS-NCI) using methane as the reagent gas. Responses were linear ranging from 0.10 to 5.00 ng/mg hair for delta(9)-THC and CBN, 0.10-10.00 ng/mg hair for CBD, 0.01-5.00 ng/mg for delta(9)-THC-COOH (r(2)>0.99). The intra-assay precisions ranged from <0.01 to 12.40%. Extraction recoveries ranged from 80.9 to 104.0% for delta(9)-THC, 85.9-100.0% for delta(9)-THC-COOH, 76.7-95.8% for CBN and 71.0-94.0% for CBD. The analytical method was applied to 87 human hair samples, obtained from individuals who testified in court of having committed drug related crimes. Quantification of delta(9)-THC-COOH using GC/MS-NCI was found to be more convenient than GC/MS-EI. The latter may give rise to false negatives due to the detection limit.     

Beyond traditional paternity and identification cases. Selecting the most probable pedigree

The paper extends on the traditional methodology used to quantify DNA evidence in paternity or identification cases. By extending we imply that there are more than two alternatives to choose between. In a standard paternity case the two competing explanations H(1): "John Doe is the father of the child and H(2): "A random man is the father of the child, are typically considered. A paternity index of 100000 implies that the data is 100000 more likely assuming hypothesis H(1) rather than H(2). If H(2) is replaced by "A brother of John Doe is the father", the LR may change dramatically. The main topic of this paper is to determine the most probable pedigree given a certain set of data including DNA profiles. In the previous example this corresponds to determining the most likely relation between John Doe and the child. Based on DNA obtained from victims of a fire, bodies found in an ancient grave or from individuals seeking to confirm their anticipated family relations, we would like to determine the most probable pedigree. The approach we present provides the possibility to combine non-DNA evidence, say age of individuals, and DNA profiles. The program familias, obtainable as shareware from http://www.nr.no/familias, delivers the probabilities for the various family constellations. More precisely, the information (if any) prior to DNA is combined with the DNA-profiles in a Bayesian manner to deliver the posterior probabilities. We exemplify using the well published Romanov data where the accepted solution emerges among 4536 possibilities considered. Various other applications based on forensic case work are discussed. In addition we have simulated data to resemble an incest case. Since the true family relation is known in this case, we may evaluate the method.     

Sensitive and specific multiresidue methods for the determination of pesticides of various classes in clinical and forensic toxicology

Original and sensitive multiresidue methods are presented for the detection and quantitation, in human biological matrices, of 61 pesticides of toxicological significance in human. These methods involved rapid solid-phase extraction using new polymeric support (HLB and MCX) OASIS cartridges. Gas chromatography-mass spectrometry (GC-MS) was used for volatile (organophosphate, organochlorine, phtalimide, uracil) pesticides and liquid chromatography-ionspray-mass spectrometry (LC-MS) for thermolabile and polar pesticides (carbamates, benzimidazoles). Acquisition was performed in the selected ion monitoring (SIM) mode. Extraction recovery varied owing to the nature of pesticides, but was satisfactory for all. Limits of detection (LODs) and limits of quantitation (LOQs) ranged, respectively, from 2.5 to 20 and from 5 to 50ng/ml. An excellent linearity was observed from LOQs up to 1000ng/ml for all the pesticides studied. The proposed procedures yielded reproducible results with good inter-assay accuracy and precision. A few cases of intoxication are presented to demonstrate the diagnostic interest of these methods: in two cases were determined lethal concentrations of endosulfan and carbofuran; in four other cases, the procedures helped diagnose intoxication with, respectively, parathion-ethyl, the association of bromacil and strychnine, bifenthrin and aldicarb.     

Do Competitive Examinations Promote Diversity in Civil Service?

The representative bureaucracy literature provides a growing body of empirical evidence that a representative public workforce enhances the efficacy and legitimacy of public services. However, little attention has been paid to the capacity of civil service competitive examinations to give equal opportunity of access to public jobs to equally competent citizens. To fill this gap, the authors use French databases to analyze whether competitive examinations comprising both written and oral tests ensure equality of treatment for all candidates regardless of gender, place of residence, or place of birth. The results challenge the capacity of these examinations to treat candidates equally, identifying inequalities in the written tests as well as evaluation biases in the oral tests. However, oral evaluation biases tend to offset inequalities in the written tests. Therefore, selection boards take a sort of affirmative action toward the sole successful members of groups suffering such inequalities.     

Pure-strategy Nash equilibrium in the spatial model with valence: existence and characterization

Public Choice - Pure-strategy Nash equilibria almost never exist in spatial majority voting games when the number of positional dimensions is at least two, as the majority core is typically empty...     

Recidivist criminal behaviour and executive functions: a comparative study

This study sought to analyse the relation between executive functions and criminal recidivism. We assessed a set of cognitive abilities associated with executive functioning in a group of recidivist offenders (n = 19), primary offenders (n = 25) and non-offenders (n = 30). Our results, tested with nonparametric statistics and Monte Carlo method, revealed that there were no executive differences between both groups of offenders but, when compared with non-offenders, the recidivists showed a worse performance in Trail Making Test part B, and the primary offenders presented a significant lower score on Porteus Maze Test Age score. This study suggests that there can be a different pattern of executive functioning deficits associated with the offenders’ criminal record: recidivism may be more related to mental flexibility impairments and primary offenders’ antisocial behaviour may be aggravated by planning deficits.     

Cognizance and Consultation of Randomized Controlled Trials among Ministerial Policy Analysts

Consultation of scientific evidence by policy actors has been the foci of attention of knowledge utilization scholars for decades. The present study questioned the extent to which randomized controlled trials (RCTs)—generally seen as the gold standard of scientific research—are known and consulted by policy analysts in ministerial settings. Using cross‐sectional data collected in 17 ministries in Québec (Canada), our study showed that fairly high levels of policy analysts report never having heard of RCTs, thus possibly hindering effective communication of scientific results to relevant policy makers. Statistical analyses reveal the importance of cognitive factors in explaining both phenomena.