Large particle number limit in rain.

The way we conceptualize rain is fundamental in many branches of science since it provides the basis not only for rain modeling notably in meteorology and hydrology, but also for interpreting rain data (from gauges and radars). In order to empirically address this question, we use stereophotographic data to measure the positions and volumes of raindrops from approximately 10 m(3) regions containing 5000-15,000 of these drops. By determining the drop statistics in spheres of increasing size, we conduct a basic continuum mechanics thought experiment. We show that-presumably due to turbulence-there is no microscale-macroscale separation. We find that the large particle number (N) limit in rain is not a homogeneous continuum, but rather it is nonclassical, strongly inhomogeneous, and approaching a multifractal discontinuum.

Selection of lymphocyte gating protocol has an impact on the level of reliability of T-cell subsets in aging specimens.

BACKGROUND: In the past decade, human immunodeficiency virus (HIV) lymphocyte immunophenotyping has evolved significantly. New fluorochromes, new multicolor reagents, enhanced instruments, and the capacity to provide absolute cell counts using the single-platform technique have all contributed to the reliability of T-cell subset measurements. In this study, four gating protocols were evaluated to select the most robust method for T-cell subset enumeration. METHODS: Peripheral blood specimens from 21 HIV(+) and 20 HIV(-) individuals were monitored up to 96 h. Aliquots of specimens were stored at room temperature and analyzed at 6 (baseline), 48, 72, and 96 h. Aliquots were stained with CD45-fluorescein isothiocyanate (FITC)/CD3PC5/CD4RD1/CD8ECD. Data analysis was performed with all four gating protocols. RESULTS: Only with fresh blood did all protocols provide similar results. From samples that were 48 h old, the choice of gating strategy had a dramatic impact on immunophenotyping results. The largest deviations from baseline values occurred at 96 h and gating protocols that included dual light scatter gates provided the greatest shift of T-cell subset values over time. The gating protocols that were based exclusively on cell lineage-specific gates gave the most robust T-cell values up to 96 h. CONCLUSION: By selecting the appropriate gating protocol, the temporal integrity of specimens can be extended up to 4 days.

Attachment and control in family and mentoring contexts as determinants of adolescent adjustment to college.

This study examined whether adolescents' perceptions of attachment security and behavioral and psychological control as experienced in family and mentoring contexts are predictive of their adjustment to college. One hundred fifty-eight academically at-risk adolescents (63 men and 95 women, 16-20 years old) completed questionnaires twice during their first semester: before and after they participated in a mentoring program. Analyses yielded 4 findings: (a) Paternal control was predictive of adolescent adjustment to college; (b) above and beyond perceptions of parental attachment and control, perception of a secure relationship with a mentor was predictive of adolescent adjustment; (c) this relationship was found to be stronger for adolescents who reported having high levels of security in the relationship with their mother; and (d) psychological control by both parents appeared to be a significant determinant of academic achievement.