Droplet-based optical trapping for cell separation in mock forensic samples

Optical tweezers have a wide range of uses for mechanical manipulation of objects in the microscopic range. This includes both living and static cells in a variety of biomedical and research applications. Single-focus optical tweezers, formed by focusing a laser beam through a high numerical aperture immersion objective, create a significant force, which enables controlled transport of a variety of different cell types and morphologies in three dimensions. Optical tweezers have been previously reported to capture and separate spermatozoa from a reconstituted simulated postcoital sample. We report herein the development of a simplified, more efficient cell transfer protocol that can separate and isolate both spermatozoa as well as leukocytes, with similar efficiencies as those previously reported. The new cell transfer method was used to separate sperm cells from a reconstituted mixture of spermatozoa and vaginal epithelial cells, with complete STR profiles developed from 50 cells with little evidence of contribution from the female contributor to the mixture. This modified protocol was then used to separate 21 samples of enriched leukocytes, with trapped cells ranging from 5 to 22 cells. Complete STR profiles were developed from as few as 10 leukocytes. Thus, with minimal sample preparation and a short trapping time, this method has the potential to provide an alternative to traditional differential extraction methods for separation of sperm:nonsperm mixtures while also providing versatility for separation of cells with differing morphologies.     

The puzzle of Dutch welfare state retrenchment

In the literature on welfare state retrenchment and in the general emphasis on the resilience of welfare states, the Dutch case appears puzzling by virtue of the fact that significant retrenchments have actually taken place in the Netherlands. It appears even more puzzling considering that the arguments in this literature as to the difficulties in welfare state retrenchments apply very well to this case, whereas the arguments as to why after all welfare state retrenchments are possible do not apply particularly well. This article argues that the explanation for the Dutch puzzle should be found in Dutch politics. Due to the power of the CDA as a pivotal centre party, the PvdA was at an early stage forced to accept welfare state retrenchment. A party consensus thus emerged allowing Dutch governments to define the issue of welfare state retrenchment as a matter of economic necessity.     

Reactions to Crime as a Hierarchy Regulating Strategy: The Moderating Role of Social Dominance Orientation

Across two studies, we demonstrated that support for group-based hierarchies differentially affects evaluation of ingroup and outgroup criminal offenders and that this effect generalizes to overall evaluations of their respective groups. Drawing on social dominance theory, our results show that differential judgments of national ingroup and immigrant outgroup offenders reflect hierarchy regulating strategies. Study 1 (N = 94) revealed that egalitarians (low on SDO) were more lenient toward outgroup offenders and their ethnic group (Arab immigrants) when compared to ingroup offenders and their national group (Swiss citizens). The opposite was true for social dominators (high on SDO). Study 2 (N = 88) replicated the results of Study 1 and further demonstrated that the socio-economic status of the perpetrator did not affect perpetrator group evaluations suggesting that the arbitrary sets of ethnicity or nationality, not education level and employment status, were the important cues for hierarchy-regulating judgments of criminal offenders.     

The Enduring Effects of Social Pressure: Tracking Campaign Experiments Over a Series of Elections

Recent field experiments have demonstrated the powerful effect of social pressure messages on voter turnout. This research note considers the question of whether these interventions’ effects persist over a series of subsequent elections. Tracking more than one million voters from six experimental studies, we find strong and statistically significant enduring effects one and sometimes two years after the initial communication.