Mobile telephone use is associated with changes in cognitive function in young adolescents

As part of the Mobile Radiofrequency Phone Exposed Users' Study (MoRPhEUS), a cross‐sectional epidemiological study examined cognitive function in secondary school students. We recruited 317, 7th grade students (144 boys, 173 girls, median age 13 years) from 20 schools around Melbourne, Australia. Participants completed an exposure questionnaire based on the Interphone study, a computerised cognitive test battery, and the Stroop colour‐word test. The principal exposure metric was the total number of reported mobile phone voice calls per week. Linear regression models were fitted to cognitive test response times and accuracies. Age, gender, ethnicity, socio‐economic status and handedness were fitted as covariates and standard errors were adjusted for clustering by school. The accuracy of working memory was poorer, reaction time for a simple learning task shorter, associative learning response time shorter and accuracy poorer in children reporting more mobile phone voice calls. There were no significant relationships between exposure and signal detection, movement monitoring or estimation. The completion time for Stroop word naming tasks was longer for those reporting more mobile phone voice calls. The findings were similar for total short message service (SMS, also known as text) messages per week, suggesting these cognitive changes were unlikely due to radiofrequency (RF) exposure. Overall, mobile phone use was associated with faster and less accurate responding to higher level cognitive tasks. These behaviours may have been learned through frequent use of a mobile phone. Bioelectromagnetics 30:678–686, 2009. © 2009 Wiley‐Liss, Inc.     

Depth utilization by Penguins and Gentoo Penguin dive patterns

Summary Time-at-depth data, recorded by animal-attached miniature depth gauges, were examined in 8 Gentoo Penguins. Birds showed two depth utiliuation patterns, (1) decreasing time with increasing depth, which we interpret as due to bounce-diving in the pelagic zone and (2) constant time per depth interval down to specific depths where large time peaks were encountered. We interprete this as flat-bottomed diving in benthic-foraging birds. Multiple maximum depth data reported in the literature for various penguin species were analysed to try and reconstruct proportional time-at-depth. These results, together with real time-at-depth data, indicated that penguin depth utilization was strongly mass dependent with larger species spending a greater proportion of time in deeper water.

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Die Tauchmuster des Eselpinguins und die räumliche Ausnutzung der Wassersäule durch Pinguine

Zusammenfassung Miniatur-Tiefenmeßgeräte wurden 8 Eselpinguinen angeheftet und die gewonnenen Daten der Aufenthaltsdauer in verschiedenen Wassertiefen untersucht. Die Vögel zeigten zwei Muster der Tiefenausnutzung, (1) abnehmende Aufenthaltsdauer mit zunehmender Wassertiefe, das wir als Stoßtauchen im Pelagial interpretieren und (2) konstante Aufenthaltsdauer pro Tiefenintervall bis in bestimmte Tiefen, in denen lange Verweildauer registriert wurden. Letzteres interpretieren wir als Grundtauchen bei Vögeln, die am Meeresboden nach Nahrung suchen. Aus der Literatur wurden multiple Tiefenmaxima für verschiedene Pinguinarten entnommen und analysiert, um die Aufenthaltsdauer pro Tiefenintervall zu rekonstruieren. Diese Ergebnisse zeigen zusammen mit tatsächlichen Meßdaten, daß die Tiefenausnutzung der Pinguine stark massenabhängig ist, wobei größere Arten eine größeren Zeitanteil in tieferem Wasser verbringen.

     

Pygoscelid penguins in a swim canal

Summary In Antarctica, we investigated the energy consumption of Adélie (Pygoscelis adeliae), Gentoo (P. papua) and Chinstrap (P. antarctica) penguins while resting in the water (8.4 W-kg^–1) and swimming underwater at various speeds, using a 21m long canal filled with sea-water at 4°C in conjunction with respirometry. The birds swam at will and consumed 15.7, 16.1 and 10 W·kg^–1 at the speed where cost of transport was minimal (2.1, 2.3 and 2.5 m·s^–1 in Adélie, Gentoo and Chinstrap penguins, respectively). Thermal conductance in pygoscelid penguins was 3.3 W·°C^–1. m^–2 and energy expenditure (P_i, W·kg^–1) while resting in the water is given by P_j = -0.3 t_a+9.6, where t_a is water temperature in °C. During the breeding season, pygoscelid penguins spend 25–40% of their daily energy expenditure while foraging at sea. The importance of accurate estimates of at-sea activity and energy consumption is discussed.     

Lekking, resource defense, and harassment in two subspecies of lechwe antelope

For lek-breeding in ungulate populations to continue, benefitsto males defending lek territories and to females visiting leksmust outweigh the costs. In this study, Kafue lechwe males onleks gained higher mating rates than nonlekking males, a resultof sexually receptive females leaving herds and aggregatingon leks. When the numbers of females on leks were experimentallyreduced, benefits to males decreased, resulting in males graduallyabandoning lek territories. A comparison with a population ofnonlekking, resource-defending black lechwe showed that matingattempts by estrous females in herds were disrupted by harassingmales eight times more frequently in a population of lek-breedingKafue lechwe than in the nonlekking black lechwe. Despite thefact that there were fewer Kafue lechwe females on single territories,harassment of estrous females by males was greater on singleterritories of Kafue lechwe than on leks and greater than onblack lechwe resource territories. Females were also absenton Kafue lechwe single territories for long periods becauseof erratic, widespread movements of compact herds resultingfrom unpredictable distributions of resources. In contrast,black lechwe females were more evenly dispersed over homogeneousresources and for a given territory, females were likely tobe present most of the time. Therefore, unlike black lechwe,male Kafue lechwe find it uneconomical to defend resource territories.Thus, costs to estrous females mating off leks and the absenceof benefits to males attempting to defend resource-based territoriesmay be important cofactors in the appearance of lek-breedingin some ungulate populations     

Typhoid outbreak in Kingston,Ont: experience with high-dose oral ampicillin.

Twenty-four children contracted typhoid fever at a summer camp near Kingston, Ont. Six were treated with chloramphenicol alone and 15 with high doses of ampicillin (300 mg/kg-d) by mouth. Ampicillin in this dosage was well tolerated except in three children in whom severe urticarial rashes developed and two who had significant diarrhea. However, high-dose oral ampicillin therapy had no advantage over that with lower doses or over chloramphenicol as judged by the rate of defervescence after the start of treatment, the rate of clinical relapse and the frequency of excretion of Salmonella typhi during convalescence.     

Heterotopic bone formation: An apparently benign complication of median sternotomy

Two cases are reported that involve heterotopic bone formation in midline sternotomy scars. The authors relate similar complications associated with abdominal incisions and discuss possible causes.     

Restriction fragment length variants in the marsupialSminthopsis crassicaudata

A fully pedigreed colony of the dasyurid marsupialSminthopsis crassicaudata has provided material for establishing two panels of DNA samples: a broad-based test panel and a two-generation family panel. These have been used to search for genetic markers in the form of restriction fragment length variants. The molecular probes—pSG-2H, a region of theS. crassicaudata embryonic -globin gene; pB8.BS, a region of the human ubiquitin gene, and p3-21a1:1, a region of the processed pseudogene of phosphoglycerate kinase-1 of the macropodid marsupialMacropus robustus—were hybridized to Southern blots ofEcoR1-digested DNA from the panels. Analysis of these blots when probed with pSG-2H provided evidence of two alleles segregating at a singleEcoR1 site. Analysis of the same blots when probed with pB8.BS suggested allelic variation at two closely linkedEcoR1 sites. Probing the blots with p3-21a1:1 produced a complex pattern of bands resembling DNA fingerprints. The presence of a 12.3-kb band was found to conform to a simple autosomal dominant mode of inheritance. Analysis of the family data, for each probe, revealed no significant departure from Mendelian inheritance. This work has provided additional genetic markers that will enhance the use ofS. crassicaudata as a model marsupial species and has demonstrated that a high level of genetic variability has been maintained in the marsupial colony.This project was supported by grants from the Australian Research Council and the University of Adelaide.     

Patterns of energy acquisition by a central place forager: benefits of alternating short and long foraging trips

In some seabirds, foraging trips have been defined as eitherlong or short, with the length of time spent traveling to theforaging area apparently a critical feature in determining foragingtrip length. Using logger technology, together with complimentarydata from published studies, we investigated traveling and foragingtimes in 18 free-living Adélie Penguins Pygoscelis adeliae,which were foraging for chicks. Most deep, foraging dives weredistributed around the center of the foraging trip. This centraltendency was particularly apparent if the cumulative amountof undulations in the depth profile (indicative of prey capture)was considered during deep dives; values started to increasebefore 20.9% and ceased after 67.2% of the dives had occurred.This concentration of the feeding activity in the middle ofthe foraging trip indicates that birds traveled to and froma prey patch whose location varied little over the birds' trips.These data form the basis for a simple model that uses travelingand foraging times together with projected rates of prey ingestionand chick and adult gastric emptying to determine that thereare occasions when, to optimize rates of prey ingestion whileat sea for both adults and chicks, birds should conduct foragingtrips of bimodal lengths.     

Piwi and piRNAs act upstream of an endogenous siRNA pathway to suppress Tc3 transposon mobility in the Caenorhabditis elegans germline

The Piwi proteins of the Argonaute superfamily are required for normal germline development in Drosophila, zebrafish, and mice and associate with 24-30 nucleotide RNAs termed piRNAs. We identify a class of 21 nucleotide RNAs, previously named 21U-RNAs, as the piRNAs of C. elegans. Piwi and piRNA expression is restricted to the male and female germline and independent of many proteins in other small-RNA pathways, including DCR-1. We show that Piwi is specifically required to silence Tc3, but not other Tc/mariner DNA transposons. Tc3 excision rates in the germline are increased at least 100-fold in piwi mutants as compared to wild-type. We find no evidence for a Ping-Pong model for piRNA amplification in C. elegans. Instead, we demonstrate that Piwi acts upstream of an endogenous siRNA pathway in Tc3 silencing. These data might suggest a link between piRNA and siRNA function.