A comparison between nomogram versus trial fitting of rigid gas permeable contact lenses

To determine the differences between prescribing a trial fitted versus a nomogram (System 10™) selected rigid gas permeable contact lens, 42 subjects were fit with one lens design on one eye and the other lens design on the opposite eye. Subjective responses for comfort and vision, objective signs of central corneal clouding, conjunctival injection, post keratometry readings, 3-9 staining, over refraction, post refraction and lens position were ranked and assigned to success levels for each eye. Subjects were evaluated at 1 week, 1 month, and 3 months. The first fit success rates were 92% for the trial fit and 86% for the nomogram fit. The trial fit lens attained significantly better outcomes in individual categories of comfort and over refraction. It was noted that the lens diameters differed significantly and a large percentage of both types of lenses benefited from a slight blend and edge modification. Although trial fitting remains the method of highest success, nomogram fitting (using System 10™) appears consistent enough to consider it an option for certain practice situations

Aspects of warm-flat directions

Considering the mechanism of dissipative slow-roll that has been used in warm inflation scenario, we show that dissipation may alter usual cosmological scenarios associated with SUSY-flat directions. We mainly consider SUSY-flat directions that have strong interactions with non-flat directions and may cause strong dissipation both in thermal and non-thermal backgrounds. An example is the Affleck-Dine mechanism in which dissipation may create significant (both qualitative and quantitative) discrepancies between the conventional scenario and the dissipative one. We also discuss several mechanisms of generating curvature perturbations in which the dissipative field, which is distinguished from the inflaton field, can be used as the source of cosmological perturbations. Considering the Morikawa-Sasaki dissipative coefficient, the damping caused by the dissipation may be significant for many MSSM flat directions even if the dissipation is far from thermal equilibrium.Comment: 22 pages, accepted for publication in International Journal of Modern Physics

Measuring final-year dental students’ ability to remove teeth independently using independence ratios

Background. Universities are obliged to ensure that dental graduates possess the necessary skills to render safe and effective treatment. Empirical evidence regarding the development of safe and effective independent practice at undergraduate level is unfortunately lacking. Objectives. To measure final-year students’ abilities to correctly perform exodontia (tooth removal/extraction) skills independently, based on the applied postgraduate progressive independence theory. Methods. Fourteen clinical teachers systematically assessed 13 263 tooth extractions completed by final-year dental students (2014 - 2016). An independence ratio (extractions performed without assistance/total number of extractions) was used as the key performance indicator to provide feedback on the ability to complete procedures independently over time. A customised index was used for controlling the level of difficulty. Results. Final-year students (n=146) achieved independence ratios ranging between 90% and 94% (standard deviation 3.3%) by the end of their clinical training. Logical gradients of increased independence were illustrated with time, as well as variable performance among students. The level of difficulty index scores remained similar within cohorts per year of study. Acceptable assessment differences existed between clinical teachers, which could largely be explained by complex operational circumstances. Conclusions. As far as we are aware, this is the first study that quantified progressive independence in exodontia for undergraduate students. The measure was sensitive enough to show logical independence gradients and variance among students. Final-year students demonstrated that they could remove >8/10 teeth independently by the time of their graduation. The measure shows promise as a proxy of competence for skills that are often practised. It is recommended that factors that influence these measurements be examined in more detail

Bigger is fitter? Quantitative genetic decomposition of selection reveals an adaptive evolutionary decline of body mass in a wild rodent population

This is the final version of the article. Available from the publisher via the DOI in this record.In natural populations, quantitative trait dynamics often do not appear to follow evolutionary predictions. Despite abundant examples of natural selection acting on heritable traits, conclusive evidence for contemporary adaptive evolution remains rare for wild vertebrate populations, and phenotypic stasis seems to be the norm. This so-called "stasis paradox" highlights our inability to predict evolutionary change, which is especially concerning within the context of rapid anthropogenic environmental change. While the causes underlying the stasis paradox are hotly debated, comprehensive attempts aiming at a resolution are lacking. Here, we apply a quantitative genetic framework to individual-based long-term data for a wild rodent population and show that despite a positive association between body mass and fitness, there has been a genetic change towards lower body mass. The latter represents an adaptive response to viability selection favouring juveniles growing up to become relatively small adults, i.e., with a low potential adult mass, which presumably complete their development earlier. This selection is particularly strong towards the end of the snow-free season, and it has intensified in recent years, coinciding which a change in snowfall patterns. Importantly, neither the negative evolutionary change, nor the selective pressures that drive it, are apparent on the phenotypic level, where they are masked by phenotypic plasticity and a non causal (i.e., non genetic) positive association between body mass and fitness, respectively. Estimating selection at the genetic level enabled us to uncover adaptive evolution in action and to identify the corresponding phenotypic selective pressure. We thereby demonstrate that natural populations can show a rapid and adaptive evolutionary response to a novel selective pressure, and that explicitly (quantitative) genetic models are able to provide us with an understanding of the causes and consequences of selection that is superior to purely phenotypic estimates of selection and evolutionary change.The study was funded by a Swiss National Science Foundation (http://www.snf.ch) project grant (31003A_141110) awarded to EP

Nanowire-based very-high-frequency electromechanical resonator

Fabrication and readout of devices with progressively smaller size, ultimately down to the molecular scale, is critical for the development of very-high-frequency nanoelectromechanical systems (NEMS). Nanomaterials, such as carbon nanotubes or nanowires, offer immense prospects as active elements for these applications. We report the fabrication and measurement of a platinum nanowire resonator, 43 nm in diameter and 1.3 µm in length. This device, among the smallest NEMS reported, has a fundamental vibration frequency of 105.3 MHz, with a quality factor of 8500 at 4 K. Its resonant motion is transduced by a technique that is well suited to ultrasmall mechanical structures

Extremal Presentations for Classical Lie Algebras

The long-root elements in Lie algebras of Chevalley type have been well studied and can be characterized as extremal elements, that is, elements $x$ such that the image of (\ad x)^2 lies in the subspace spanned by $x$. In this paper, assuming an algebraically closed base field of characteristic not 2, we find presentations of the Lie algebras of classical Chevalley type by means of minimal sets of extremal generators. The relations are described by simple graphs on the sets. For example, for $C_n$ the graph is a path of length $2n$, and for $A_n$ the graph is the triangle connected to a path of length $n-3$.Comment: 26 pages, 6 figure

Free energy of hydrophobic hydration:A molecular dynamics study of noble gases in water

The potential utility and limitations of two methods to determine free energy differences from molecular dynamics simulations (MD) are studied. The computation of the free energy of hydration of the inert gases serves as a simple but illustrative example. Good results are obtained for the inert gases from a perturbation treatment, using a reference ensemble obtained from a MD simulation of a cavity in water, if these atoms are comparable in size to the cavity and the calculated free energy differences are small. This limits the applicability of the perturbation treatment of a small number of cases. Larger free energy differences can be obtained with reasonable accuracy from MD simulations with continuously changing interaction parameters. This integration method is more generally applicable, but makes an additional simulation necessary

Sneutrino condensate as a candidate for the hot big bang cosmology

If inflationary paradigm is correct, then it must create conditions for the hot big bang model with all observed matter, baryons and the seed perturbations for the structure formation. In this paper we propose a scenario where the inflaton energy density is dumped into the bulk in a brane world setup, and all the required physical conditions are created by the right handed neutrino sector within supersymmetry. The scalar component of the right handed Majorana neutrino is responsible for generating the scale invariant fluctuations in the cosmic microwave background radiation, reheating the Universe at a temperature~$T_{rh}\leq 10^{9}$ GeV, and finally generating the lepton/baryon asymmetry, $n_{B}/s\sim 10^{-10}$, with no lepton/baryon isocurvature fluctuations.Comment: 19 pages, 3 figures. Some discussion on neutrino masses and baryogenesis, and other small changes adde

Disentangling evolutionary, plastic and demographic processes underlying trait dynamics: a review of four frameworks

This is the author accepted manuscript. The final version is available from Wiley via the DOI in this record.Biologists are increasingly interested in decomposing trait dynamics into underlying processes, such as evolution, plasticity and demography. Four important frameworks that allow for such a decomposition are the quantitative genetic animal model (AM), the ‘Geber’ method (GM), the age-structured Price equation (APE) and the integral projection model (IPM). However, as these frameworks have largely been developed independently, they differ in the assumptions they make, the data they require, as well as their outcomes and interpretation. Here, we evaluate how each framework decomposes trait dynamics into underlying processes. To do so, we apply them to simulated data for a hypothetical animal population. Individual body size was affected by, among others, genes, maternal effects and food intake. We simulated scenarios with and without selection on body size and with high and low heritability. The APE and IPM provided similar results, as did the AM and GM, with important differences between the former and the latter. All frameworks detected positive contributions of selection in the high but not in the low selection scenarios. However, only the AM and GM distinguished between the high and low heritability scenarios. Furthermore, the AM and GM revealed a high contribution of plasticity. The APE and IPM attributed most of the change in body size to ontogenetic growth and inheritance, where the latter captures the combined effects of plasticity, maternal effects and heritability. We show how these apparent discrepancies are mostly due to differences in aims and definitions. For example, the APE and IPM capture selection, whereas the AM and GM focus on the response to selection. Furthermore, the frameworks differ in the processes that are ascribed to plasticity and in how they take into account demography. We conclude that no single framework provides the ‘true’ contributions of evolution, plasticity and demography. Instead, different research questions require different frameworks. A thorough understanding of the different definitions of their components is necessary for selecting the most appropriate framework for the question at hand and for making biologically meaningful inferences. This work thus supports both future analysis and the careful interpretation of existing work.This work was funded by the Swiss NationalScience Foundation project grants (31003A_141110 and 31003A_159462/1 toEP, 31003A_146445 to AO) and an ERC starting grant (#337785 to AO)

Keeping Your Eyes Continuously on the Ball While Running for Catchable and Uncatchable Fly Balls

When faced with a fly ball approaching along the sagittal plane, fielders need information for the control of their running to the interception location. This information could be available in the initial part of the ball trajectory, such that the interception location can be predicted from its initial conditions. Alternatively, such predictive information is not available, and running to the interception location involves continuous visual guidance. The latter type of control would predict that fielders keep looking at the approaching ball for most of its flight, whereas the former type of control would fit with looking at the ball during the early part of the ball's flight; keeping the eyes on the ball during the remainder of its trajectory would not be necessary when the interception location can be inferred from the first part of the ball trajectory. The present contribution studied visual tracking of approaching fly balls. Participants were equipped with a mobile eye tracker. They were confronted with tennis balls approaching from about 20 m, and projected in such a way that some balls were catchable and others were not. In all situations, participants almost exclusively tracked the ball with their gaze until just before the catch or until they indicated that a ball was uncatchable. This continuous tracking of the ball, even when running close to their maximum speeds, suggests that participants employed continuous visual control rather than running to an interception location known from looking at the early part of the ball flight.</p