Silica-based highly nonlinear fibers with a high SBS threshold

Results on suppression of stimulated Brillouin scattering in highly nonlinear fibers with germanium-doped core as well as aluminum-doped core based on spooling the fiber with a linear strain gradient is presented

Sexing Viking Age horses from burial and non-burial sites in Iceland using ancient DNA

© 2018 The Authors Horses are the most common grave goods found in Icelandic Viking Age graves. Horse skeletons have previously been sexed based on pelvis shape and the presence of canine teeth in male horses over 4–5 years of age. Morphological data has shown that all horses from Icelandic burials that were amenable to sexing were male. Yet the use of morphological methods to determine sex is problematic since they rely on finding a well-preserved pelvis and/or robust canine teeth. Furthermore, quantitative data underlying the features of the horse pelvis used for sexing is lacking and canine teeth have been reported to occur in mares. In this study we build upon and extend recently developed methodologies to make use of shotgun sequencing of ancient DNA (aDNA) for molecular sexing of Viking Age horse remains. With minimal sequencing effort we identified the sex of the largest collection (n = 22) of Viking Age Icelandic horses studied to date, sourced from both burial (n = 19) and non-burial (n = 3) sites. Our results revealed a male to female sex bias ratio of 18:1 in burial sites, versus 0:3 in non-burial sites. These findings support the significant over-representation of male horses in Viking Age graves in Iceland, yet show that –albeit rare– mares could also be selected for ritual burial in Viking Age Iceland. This cost-effective method provides statistical confidence to allow for sexing of highly fragmented archaeological specimens with low endogenous DNA content

Building blocks for social accountability: a conceptual framework to guide medical schools

Background: This paper presents a conceptual framework developed from empirical evidence, to guide medical schools aspiring towards greater social accountability. Methods: Using a multiple case study approach, seventy-five staff, students, health sector representatives and community members, associated with four medical schools, participated in semi-structured interviews. Two schools were in Australia and two were in the Philippines. These schools were selected because they were aspiring to be socially accountable. Data was collected through on-site visits, field notes and a documentary review. Abductive analysis involved both deductive and inductive iterative theming of the data both within and across cases. Results: The conceptual framework for socially accountable medical education was built from analyzing the internal and external factors influencing the selected medical schools. These factors became the building blocks that might be necessary to assist movement to social accountability. The strongest factor was the demands of the local workforce situation leading to innovative educational programs established with or without government support. The values and professional experiences of leaders, staff and health sector representatives, influenced whether the organizational culture of a school was conducive to social accountability. The wider institutional environment and policies of their universities affected this culture and the resourcing of programs. Membership of a coalition of socially accountable medical schools created a community of learning and legitimized local practice. Communities may not have recognized their own importance but they were fundamental for socially accountable practices. The bedrock of social accountability, that is, the foundation for all building blocks, is shared values and aspirations congruent with social accountability. These values and aspirations are both a philosophical understanding for innovation and a practical application at the health systems and education levels. Conclusions: While many of these building blocks are similar to those conceptualized in social accountability theory, this conceptual framework is informed by what happens in practice - empirical evidence rather than prescriptions. Consequently it is valuable in that it puts some theoretical thinking around everyday practice in specific contexts; addressing a gap in the medical education literature. The building blocks framework includes guidelines for social accountable practice that can be applied at policy, school and individual levels

Molecular Basis for Atovaquone Binding to the Cytochrome bc 1 Complex

Atovaquone is a substituted 2-hydroxynaphthoquinone that is used therapeutically to treat Plasmodium falciparum malaria, Pneumocystis carinii pneumonia, and Toxoplasma gondii toxoplasmosis. It is thought to act on these organisms by inhibiting the cytochrome bc1 complex. We have examined the interaction of atovaquone with the bc1 complex isolated from Saccharomyces cerevisiae, a surrogate, nonpathogenic fungus. Atovaquone inhibits the bc1 complex competitively with apparent Ki = 9 nm, raises the midpoint potential of the Rieske iron-sulfur protein from 285 to 385 mV, and shifts the g values in the EPR spectrum of the Rieske center. These results indicate that atovaquone binds to the ubiquinol oxidation pocket of the bc1 complex, where it interacts with the Rieske iron-sulfur protein. A computed energy-minimized structure for atovaquone liganded to the yeast bc1 complex suggests that a phenylalanine at position 275 of cytochrome b in the bovine bc1 complex, as opposed to leucine at the equivalent position in the yeast enzyme, is responsible for the decreased sensitivity of the bovine bc1 complex (Ki = 80 nm) to atovaquone. When a L275F mutation was introduced into the yeast cytochrome b, the sensitivity of the yeast enzyme to atovaquone decreased (Ki = 100 nm) with no loss in activity, confirming that the L275F exchange contributes to the differential sensitivity of these two species to atovaquone. These results provide the first molecular description of how atovaquone binds to the bc1 complex and explain the differential inhibition of the fungal versus mammalian enzymes

A Novel Tongue-based Remote Control and the Implication of Adaptive Semi-automation, Fixed Semi-Automation and Manual Control of a Wheelchair mounted Assistive Robotic Manipulator

Abstract— Increasing the independence of individuals withtetraplegia is a challenging task. One potential solution is to allowfor use of assistive robotics, specifically an assistive roboticmanipulator (ARM), when solving varying tasks in personal andremote space. Allowing for remote performances has a positiveinfluence on the independence of the user, allowing the user to beself-sufficient even when lying in bed. The control interfaces thatare suitable for severely disabled individuals is lacking. The aim ofthis paper is twofold: to allow for remote tongue-based control ofan ARM and second, to compare the effect of semi-automation onthe control of a robotic ARM. Ten able-bodied individualsparticipated in a two-day experiment where they were asked todrive a wheelchair mounted ARM away from the participant andout of sight. Thereafter, they should either pick up a strawberryor a bottle from a table. All the participants successfully finishedthree trials for three different control methods: 1) manual control(MA), 2) adaptive level semi-automation (SA), and 3) fixed levelsemi-automation (FA). When grasping the strawberry, there wasa significant decrease in the gripping time and number of usedcommands when using FA compared to MA. When grasping thebottle, the SA showed a significant reduction in gripping time andnumber of used commands compared with MA. This paper is astep in the direction of providing severely paralyzed individualswith a way to increase their independence and overall quality oflife

Silica-based highly nonlinear fibers with a high SBS threshold

Results on the suppression of stimulated Brillouin scattering in highly non linear fibers with both germanium- and aluminum-doped cores based on spooling the fiber with a linear strain gradient are compared and presented

Brillouin Suppressed Highly Nonlinear Fibers

Methods for suppression of stimulated Brillouin scattering in highly nonlinear fibers are reviewed. Emphasis is paid to SBS suppression by aluminum doping of the core. New results for a HNLF with an aluminum doped core and reduced loss are presented

A silica based highly nonlinear fibre with improved threshold for stimulated Brillouin scattering

8.8 dB improvement in figure of merit for SBS limited highly nonlinear fibres is reported by using a combination of Al-doping and straining of the fibre