Temperature-Induced Phase Shift of Daily Rhythm of Serum Prolactin in Gulf Killifish

Daily variations in circulating levels of the pituitary hormone prolactin have been reported in several vertebrates, including fishes. In some animals, the 24-h rhythm changes seasonally with respect to the time of day that maximum and minimum prolactin levels occur. It has been hypothesised that this seasonal change in phase of prolactin rhythm is an important component of the mechanism controlling seasonality in vertebrates. Because water temperature is generally considered the principal environmental regulator of seasonal changes in reproduction and metabolism in many fishes, including the gulf killifish Fundulus grandis, we determined the daily rhythm of serum prolactin concentrations in fish held at temperatures that are stimulatory (20 °C) or inhibitory (28 °C) for reproductive development. We found that an increase in water temperature from 20° to 28 °C phase shifts the daily variation of serum prolactin with respect to the daily photoperiod in F. grandis

Evolving Clustered Random Networks

We propose a Markov chain simulation method to generate simple connected random graphs with a specified degree sequence and level of clustering. The networks generated by our algorithm are random in all other respects and can thus serve as generic models for studying the impacts of degree distributions and clustering on dynamical processes as well as null models for detecting other structural properties in empirical networks

Historical explosive activity of Mount Melbourne Volcanic Field (Antarctica) revealed by englacial tephra deposits

Five tephra layers named BRH1 to 5 were sampled in an ice cliff located on the north-eastern flank of Mount Melbourne (northern Victoria Land, Antarctica). The texture, componentry, mineralogy, and major and trace element compositions of glass shards have been used to characterize these layers. These properties suggest that they are primary fall deposits produced from discrete eruptions that experienced varying degrees of magma/water interaction. The major and trace element glass shard analyses on single glass shards indicate that Mount Melbourne Volcanic Field is the source of these tephra layers and the geochemical diversity highlights that the eruptions were fed by compositionally diverse melts that are interpreted to be from a complex magma system with a mafic melt remobilizing more evolved trachy-andesitic to trachytic magma pockets. Geochemical compositions, along with textural and mineralogical data, have allowed correlations between two of the englacial tephra and distal cryptotephra from Mount Melbourne, recovered within a marine sediment core in the Edisto Inlet (~ 280 km northeast of Mount Melbourne), and constrain the age of these englacial tephra layers to between the third and the fourth century CE. This work provides new evidence of the intense historical explosive activity of the Mount Melbourne Volcanic Field and better constrains the rates of volcanism in northern Victoria Land. These data grant new clues on the eruptive dynamics and tephra dispersal, and considerably expand the geochemical (major and trace elements) dataset available for the Mount Melbourne Volcanic Field. In the future, this will facilitate the precise identification of tephra layers from this volcanic source and will help define the temporal and spatial correlation between Antarctic records using tephra layers. Finally, this work also yields new valuable time-stratigraphic marker horizons for future dating, synchronization, and correlations of different palaeoenvironmental and palaeoclimatic records across large regions of Antarctica

The role of paediatric nurses in medication safety prior to the implementation of electronic prescribing:a qualitative case study

Objectives: To explore paediatric nurses’ experiences and perspectives of their role in the medication process and how this role is enacted in everyday practice. Methods: A qualitative case study on a general surgical ward of a paediatric hospital in England, one year prior to the planned implementation of ePrescribing. Three focus groups and six individual semi-structured interviews were conducted, involving 24 nurses. Focus groups and interviews were audio-recorded, transcribed, anonymized and subjected to thematic analysis. Results: Two overarching analytical themes were identified: the centrality of risk management in nurses’ role in the medication process and the distributed nature of nurses’ medication risk management practices. Nurses’ contribution to medication safety was seen as an intrinsic feature of a role that extended beyond just preparing and administering medications as prescribed and placed nurses at the heart of a dynamic set of interactions, practices and situations through which medication risks were managed. These findings also illustrate the collective nature of patient safety. Conclusions: Both the recognized and the unrecognized contributions of nurses to the management of medications needs to be considered in the design and implementation of ePrescribing systems

A cost effectiveness and capacity analysis for the introduction of universal rotavirus vaccination in Kenya : comparison between Rotarix and RotaTeq vaccines

Background Diarrhoea is an important cause of death in the developing world, and rotavirus is the single most important cause of diarrhoea associated mortality. Two vaccines (Rotarix and RotaTeq) are available to prevent rotavirus disease. This analysis was undertaken to aid the decision in Kenya as to which vaccine to choose when introducing rotavirus vaccination. Methods Cost-effectiveness modelling, using national and sentinel surveillance data, and an impact assessment on the cold chain. Results The median estimated incidence of rotavirus disease in Kenya was 3015 outpatient visits, 279 hospitalisations and 65 deaths per 100,000 children under five years of age per year. Cumulated over the first five years of life vaccination was predicted to prevent 34% of the outpatient visits, 31% of the hospitalizations and 42% of the deaths. The estimated prevented costs accumulated over five years totalled US$1,782,761 (direct and indirect costs) with an associated 48,585 DALYs. From a societal perspective Rotarix had a cost-effectiveness ratio of US$142 per DALY (US$5 for the full course of two doses) and RotaTeq US$288 per DALY ($10.5 for the full course of three doses). RotaTeq will have a bigger impact on the cold chain compared to Rotarix. Conclusion Vaccination against rotavirus disease is cost-effective for Kenya irrespective of the vaccine. Of the two vaccines Rotarix was the preferred choice due to a better cost-effectiveness ratio, the presence of a vaccine vial monitor, the requirement of fewer doses and less storage space, and proven thermo-stability

Effect of correlations on network controllability

A dynamical system is controllable if by imposing appropriate external signals on a subset of its nodes, it can be driven from any initial state to any desired state in finite time. Here we study the impact of various network characteristics on the minimal number of driver nodes required to control a network. We find that clustering and modularity have no discernible impact, but the symmetries of the underlying matching problem can produce linear, quadratic or no dependence on degree correlation coefficients, depending on the nature of the underlying correlations. The results are supported by numerical simulations and help narrow the observed gap between the predicted and the observed number of driver nodes in real networks

Fluoromycobacteriophages for rapid, specific, and sensitive antibiotic susceptibility testing of Mycobacterium tuberculosis

Rapid antibiotic susceptibility testing of Mycobacterium tuberculosis is of paramount importance as multiple- and extensively- drug resistant strains of M. tuberculosis emerge and spread. We describe here a virus-based assay in which fluoromycobacteriophages are used to deliver a GFP or ZsYellow fluorescent marker gene to M. tuberculosis, which can then be monitored by fluorescent detection approaches including fluorescent microscopy and flow cytometry. Pre-clinical evaluations show that addition of either Rifampicin or Streptomycin at the time of phage addition obliterates fluorescence in susceptible cells but not in isogenic resistant bacteria enabling drug sensitivity determination in less than 24 hours. Detection requires no substrate addition, fewer than 100 cells can be identified, and resistant bacteria can be detected within mixed populations. Fluorescence withstands fixation by paraformaldehyde providing enhanced biosafety for testing MDR-TB and XDR-TB infections. © 2009 Piuri et al