The Myth of Male Superiority: Rise and Demise

A prolific literature exists concerning the origins and functions of the institutionalization of sex-role differences. However, persistent problems and sharply divergent views remain. This study attempts to circumvent the nature/nurture controversy by utilizing a holistic-evolutionary approach to the problem. The reviews of evidence from ethology, developmental psychology, and cross-cultural investigations lead to a social-exchange model involving differences in the elasticities of male and female labor contributions in social evolution. Assumptions about future technological progress lead to prediction of the demise of the myth of male supremacy. [sex differences in social evolution, ontogeny of human behavior]     

Safely Discharging Infants with Bronchiolitis from an Emergency Department: A Five Step Guide for Pediatricians

Recent publications have established the pulse oxygen saturation (SpO₂) threshold of 90% for the hospitalization and discharge of infant patients with bronchiolitis. However, there is no clear recommendation regarding the Emergency Department (ED) observation period necessary before allowing safe home discharge for patients with SpO₂ above 90%-92%. Our primary aims were to evaluate the risk factors associated with delayed desaturation in infants with SpO₂ ≥ 92% on arrival at the ED as well as the ED observation period necessary before allowing safe home discharge. A secondary aim was to identify the risk factors for ED readmission. Of 581 episodes of bronchiolitis in patients < 1 year old admitted to the ED, only 47 (8%) had SpO₂ < 92% on arrival there, although 106 (18%) exhibited a delayed desaturation (to < 92%) during ED observation. Female sex, age < 3 months old, ED readmission, more severe initial clinical presentation, and higher pCO₂ level (> 6KPa) were risk factors for delayed desaturation with OR varying from 1.7 to 7.5. In patients < 3 months old, mean desaturation occured later than in older patients [6.0 hours (IQR 3.0–14.0) vs. 3.0 hours (IQR 2.0–6.0), P = 0.0018]. In 95% of patients with a delayed desaturation this decrease occurred within 25 hours for patients < 3 months old and within 11 hours for patients ≥ 3 months old. In patients < 3 months old with respiratory rates above the normal range for their age the desaturation occurred earlier than in patients < 3 months with normal respiratory rates [4.4 hours (IQR 3.0–11.7) vs. 14.6 hours (IQR 7.6–22.2), P = 0.037]. Based on the present study’s results, we propose a five step guide for pediatricians on discharging children with bronchiolitis from the ED. By using the threshold of an 11 hour ED observation period for patients ≥ 3 months old and a 25 hour period for patients < 3 months old we are able to detect 95% of the patients with bronchiolitis who are at risk of delayed desaturation.     

Structural determinants of an internal ribosome entry site that direct translational reading frame selection

The dicistrovirus intergenic internal ribosome entry site (IGR IRES) directly recruits the ribosome and initiates translation using a non-AUG codon. A subset of IGR IRESs initiates translation in either of two overlapping open reading frames (ORFs), resulting in expression of the 0 frame viral structural polyprotein and an overlapping +1 frame ORFx. A U–G base pair adjacent to the anticodon-like pseudoknot of the IRES directs +1 frame translation. Here, we show that the U-G base pair is not absolutely required for +1 frame translation. Extensive mutagenesis demonstrates that 0 and +1 frame translation can be uncoupled. Ribonucleic acid (RNA) structural probing analyses reveal that the mutant IRESs adopt distinct conformations. Toeprinting analysis suggests that the reading frame is selected at a step downstream of ribosome assembly. We propose a model whereby the IRES adopts conformations to occlude the 0 frame aminoacyl-tRNA thereby allowing delivery of the +1 frame aminoacyl-tRNA to the A site to initiate translation of ORFx. This study provides a new paradigm for programmed recoding mechanisms that increase the coding capacity of a viral genome.     

Sterilization by Cooling in Isochoric Conditions: The Case of Escherichia coli

High hydrostatic pressure (HHP) affects the structure, metabolism and survival of micro-organisms including bacteria. For this reason HHP is a promising treatment in the food industry. The aim of this work is to evaluate the effect of high pressure, under isochoric cooling conditions, on Escherichia coli, where such high pressure develops due to the fact water cannot expand. We combine survival curves obtained by spectrophotometry and images of atomic force microscopy in this study. Our results show that cooling at -20 and -30°C leads to a partial destruction of a Escherichia coli population. However, cooling at -15°C causes a total extermination of bacteria. This intriguing result is explained by the phase diagram of water. In the first case, the simultaneous formation of ice III and ice Ih crystals provides a safe environment for bacteria. In the second case (-15°C) Escherichia coli remains in a metastable and amorphous free-of-crystals liquid subjected to high pressure. Our work is the first experimental study carried out to inactivate Escherichia coli under isochoric cooling conditions. Unlike HHP, which is based on the application of an external load to augment the pressure, this technique only requires cooling. The method could be used for annihilation of other Escherichia coli strains and perhaps other micro-organisms.     

Reproduction and baeocyte formation in two species of Dermocarpella (Cyanophyceae)

The reproductive stages of Dermocarpella gardneri and D. stellata, which have been reported only once, are described. Formation of baeocytes occurs by cellular divisions that are parallel to the substratum, followed by a series of anticlinal radial divisions. In some cases in D. gardneri, the superior cell, resulting from the first division parallel to the substratum, is liberated prior to radial divisions, and these probably represent the ‘macrogonidia’ originally described by Lemmermann for D. hemisphaerica. The baeocytes are released through a circular apical pore, which develops after the formation of a papilla that eventually dissolves to form a pore.