Characterization of gunpowder samples using time-of-flight secondary ion mass spectrometry (TOF-SIMS)

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was utilized to obtain characteristic mass spectra from three different smokeless powders and six different black powder samples. In these mass spectra, peaks indicative of both the organic and inorganic additive constituents in the gunpowders were observed. TOF-SIMS was able to successfully differentiate between the different black and smokeless gunpowder samples analyzed with the aid of principal components analysis (PCA), a multivariate statistical analysis approach often used to reduce the dimensionality of complex data. TOF-SIMS was also used to obtain information about the spatial distribution of the various additives contained within the gunpowder samples. SIMS imaging demonstrated that that the samples could potentially be characterized by their 2-D structure, which varied from sample to sample. These results clearly demonstrate the feasibility of utilizing TOF-SIMS as a tool for the characterization and differentiation of gunpowder samples for general forensic applications.     

The ‘Lab Leak Lie' Is Racist

正The lab leak lie is racist.To be clear,the unscientific surmise that COVID-19 was spread intentionally or unintentionally by a Chinese government laboratory in Wuhan is racist.From the beginning,this lie was an expression of dog-whistle politics,one that has exploited longstanding racial stereotypes,and that has in turn deepened anti-Asian racism in many countries around the world.Stoking the fires The fact that the Donald Trump administration promoted the lab leak lie in 2020 is not surprising.Before the outbreak,     

Developmental trajectories of nonsocial reinforcement and offending in adolescence and young adulthood: An exploratory study of an understudied part of social learning theory

Purpose

Within social learning theory, nonsocial reinforcement has been hypothesized to have a link with offending. The purpose of the present study was to address two questions: (1) Does nonsocial reinforcement change or remain stable over time? And (2) does nonsocial reinforcement have a reciprocal link with offending, as Wood et al. (1997) would expect?

Methods

We used a subsample (N = 413) of the National Longitudinal Survey of Youth (NLSY) data and semi-parametric group-based modeling (SPGM).

Results and Conclusions

The SPGM suggested three distinct groups of nonsocial reinforcement (one trajectory group appeared to have a low but stable rate of nonsocial reinforcement, one trajectory appeared to be higher but stable, another trajectory higher but also stable). A cross-tabulation of the nonsocial reinforcement trajectories and offending trajectories indicated that offending increased as nonsocial reinforcement became greater. Study limitations and implications are also discussed.