layer is not altered by a five-hundred fold change in the surrounding pressure. Further evidence for believing that a condition characteristic of the metal itself has been reached is furnished by the fact that the photoelectric sensitivity of an outgassed specimen remains constant for twelve hours after heat treatment. The work of Davisson and Germer9 on electron reflection from nickel is also ...

The phylogeny of the corbiculate bees, which include the major groups of highly eusocial bees, is controversial. In an attempt to resolve the controversy, Ascher et al. (2001) argued that they have expanded a prior phylogenetic analysis of the corbiculate bees based on opsin (LW Rh) sequences reported by Mardulyn and Cameron (1999) ‘‘to more critically assess opsin s phylogenetic utility.’’ The...

We derive a new existence condition for Cameron – Liebler line classes in PG(3, q). As an application, we obtain the characterization of Cameron – Liebler line classes in PG(n, 4), n ≥ 3.

Cameron–Liebler line classes are sets of lines in PGð3; qÞ that contain a fixed number x of lines of every spread. Cameron and Liebler classified them for x A f0; 1; 2; q 1; q; q þ 1g and conjectured that no others exist. This conjecture was disproven by Drudge and his counterexample was generalised to a counterexample for any odd q by Bruen and Drudge. Nonexistence of Cameron–Liebler line clas...

INTRODUCTION Routine prenatal human immunodeficiency virus (HIV) screening provides a critical opportunity to diagnose HIV infection, begin chronic care, and prevent mother-to-child transmission. However, little is known about the prevalence of prenatal HIV testing in the US-Mexico border region. We explored the correlation between prenatal HIV testing and sociodemographic, health behavior, and...

Nine species of the Parapolybia indica species-group in eastern parts of Asia are reviewed. Four new species are described: P. flava sp. nov. (Vietnam), P. crocea sp. nov. (Japan), P. nana sp. nov. (Vietnam), and P. albida sp. nov. (Vietnam). Parapolybia indica (de Saussure, 1854), P. bioculata van der Vecht, 1966 and P. tinctipennis (Cameron, 1900) are redescribed. The status is reinstanted fo...

Japanese species of the genus Xanthopimpla Saussure, 1892 are revised. A total 15 recorded from Japan, including three new species, X. nipponensis sp. nov . sylvicola nov. and yoshimurai honorata (Cameron, 1899), minuta Cameron, 1905 trias Townes & Chiu, 1970, newly Japan. Host, habitat, overwintering distribution patterns discussed.