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Experiments were conducted during November 2003 in the dry core of the Atacama Desert, Yungay, Chile to test the hypothesis that UV radiation, in environments where liquid water is not available, and thus enzymatic repair of UV-induced damage is inhibited, can prevent epilithic colonization. Novel dosimeters made from the cryptoendolithic, desiccation and radiation-resistant cyanobacterium Chroococcidiopsis sp. isolated from the dry Negev desert, Israel, showed that monolayers of this organism were killed within one day. The diurnal profile of microbial loss of viability was investigated with dosimeters of Bacillus subtilis, which similarly showed cell death within one day. Soil grains obtained from south of Yungay where liquid water is more abundant and transported to the hyperarid core showed killing of indigenous vegetative organisms within one day. Gypsum and mineral grain coverings of 1 mm were sufficient to prevent measurable UV-induced damage of Chroococcidiopsis and B. subtilis after 8 d exposure. These results show that under extreme desiccation and an ambient UV flux the surface of rocks can potentially be rendered sterile, but that millimetre thick mineral coverings can protect organisms from UV-induced killing, consistent with the observed patterns of lithophytic colonization in the Atacama Desert. These data further show that UV radiation can be an important limiting factor in surface biological rock weathering in arid regions.

In this article, we discuss antimicrobial regimens for both outpatient and inpatient use in infants and children. A substantial number of pediatric patient visits annually result in the prescribing of antimicrobial drugs. The emergence of bacteria resistant to commonly used antimicrobial agents is a growing concern. Information on newer drugs such as meropenem, which is active against penicillin-resistant Streptococcus pneumoniae and gram-negative bacilli, and cefepime, which has activity against gram-negative bacilli including Pseudomonas aeruginosa and against gram-positive cocci is also presented. Management of patients with congenital or acquired immunodeficiencies continues to be challenging in regard to the use of antimicrobial drugs to treat various fungal and viral infections. New formulations of older drugs such as aerosolized tobramycin and amphotericin B lipid complex are available. New antiviral agents have been approved, most of which are antiretroviral agents. Childhood tuberculosis is an ongoing concern, and regimens to treat Mycobacterium tuberculosis in children are discussed.

Background The ability to discriminate cuteness may aid caregivers in prioritising care to the neediest child. This biologically important ability has been indirectly linked to higher levels of female reproductive hormones via studies of hormonal contraception and menopausal status. Pregnancy provides an opportunity to further investigate the role of reproductive hormones in cuteness discrimination since it is a time of substantial natural hormonal fluctuation. Methods Pregnant (n=23) and matched non-pregnant women (n=11) were assessed four times over 8 months (at 20 weeks of gestation, 32 weeks of gestation, 2 weeks postpartum, 12 weeks postpartum). At each visit, cuteness sensitivity, cuteness intensity ratings, and basic visuospatial perception were assessed. Cuteness sensitivity was assessed by presenting two versions of the same face side by side, with one subtly altered by graphics software to be more or less cute than the other; women were asked to select the cuter face. Cuteness intensity was rated on a seven-point Likert scale. Results were analysed with repeated measures ANOVA. Findings There was no difference between pregnant/postpartum mothers and control women in cuteness sensitivity, cuteness intensity ratings, or basic visuospatial perception. There was no change in these abilities across time. Interpretation This result is not what we hypothesised. It seems that the link between female reproductive hormones and cuteness sensitivity is more indirect and complex than initially thought. Possibly female reproductive hormones other than those elevated in pregnancy are important in determining cuteness sensitivity. Funding Wellcome Trust.