Avoiding dead ends: the experimental evolution of constraint as adaptation to environmental variation in Saccharomyces cerevisiae

Environmental unpredictability results in the evolution of bet-hedging traits, which maximize long-term fitness but are, by definition, suboptimal over short time scales. However, because suboptimal traits are expected to be purged by selection in the shorter term, the persistence of bet hedging remains perplexing. Here, we test the hypothesis that bet hedging persists through the evolution of constraint on short-term adaptation. We experimentally evolve Saccharomyces cerevisiae across two sequential treatments in which the frequency of extreme heat shocks decreases. We predict that experimental evolution under lower frequency heat shocks will result in greater adaptive constraint, or “purge-resistant” bet hedging. Constraint is assayed as evolutionary persistence of heat shock tolerance (HST) under constant benign conditions. As predicted, we find the retention of HST only in lines evolved under reduced frequency detrimental conditions. Results help explain the evolution of bet hedging, and challenge the traditional view that evolutionary constraint is inherently maladaptive.

Changes in food habits amongst Norwegian adolescents in 2016 and 2019 according to gender and socioeconomic status

Background: Monitoring dietary habits is important in order to identify risk groups and as a basis for targeted public health initiatives. Objective: To study trends in consumption of selected foods and beverages from 2016 to 2019 amongst Norwegian adolescents according to gender and parental education. Design: Repeated cross-sectional study amongst 25,996 adolescents, aged 14–17 years old. Consumption of selected food and beverages was measured by an online food frequency questionnaire and general linear models were applied to estimate changes in dietary habits. Results: Between 2016 and 2019, we observed a reduced frequency of consumption of vegetables (from 4.7 to 4.4 times/week), fruit and berries (from 4.4 to 4.2 times/week), whole-grain bread (from 5.1 to 4.2 times/week), and fish (from 2.3 to 1.6 times/week). During this time period, we also observed a reduced frequency of consumption of salty snacks (from 2.1 to 1.9 times/week), sweets (from 2.3 to 2.0 times/week), sugar-sweetened beverages (from 2.8 to 2.6 times/week), and artificially sweetened beverages (from 2.2 to 1.5 times/week). In girls, there was a decrease in the reported frequency of consumption of fruit and berries (−4%, vs. no change in boys). The decrease in consumption frequency of whole-grain bread was larger in girls than in boys (−19% vs. −14%). Further, a 17% decrease in consumption of sweets was observed amongst adolescents with no or only one parent having college/university education compared to a 13% decrease in adolescents whose both parents had college/university education. Conclusion: Our results showed a decrease in frequency of consumption of selected healthy and unhealthy food and beverages amongst adolescents between 2016 and 2019. The gender gap in consumption of fruit and berries and whole-grain bread seemed to decrease during this time period, and the socio-economic gap in consumption of sweets seemed to disappear.

Dynamic Stall Characteristics of Pitching Swept Finite-Aspect-Ratio Wings

An experimental investigation regarding the dynamic stall of various swept wing models with pitching motion was performed to analyze the effect of sweep on the dynamic stall. The experiments were performed on a wing with a NACA0012 airfoil section with an aspect ratio of AR = 4. The experimental study was conducted for chord-based Reynolds number Rec =2×105 and freestream Mach number Ma=0.1. First, a ‘particle image velocimetry’ (PIV) experiment was performed on the wing with three sweep angles, Λ=0o, 15o, and 30o, to obtain the flow structure at several wing spans. The results obtained at a reduced frequency showed that a laminar separation bubble forms at the leading edge of the wing during upward motion. As the upward pitching motion continues, a separation burst occurs and shifts towards the wing trailing edge. As the wing starts to pitch downward, the growing dynamic stall vortex (DSV) vortex sheds from the wing’s trailing edge. With the increasing sweep angle of the wing, the stall angle is delayed during the dynamic motion of the wing, and the presence of DSV shifts toward the wingtip. During the second stage, a ‘turbo pressure-sensitive paint’ (PSP) technique was deployed to obtain the phase average of the surface pressure patterns of the DSV at a reduced frequency, k=0.1. The phase average of pressure shows a distinct pressure map for two sweep angles, Λ=0o, 30o, and demonstrates a similar trend to that presented in the published computational studies and the experimental data obtained from the current PIV campaign.

Minimally invasive biological treatment in endodontics

Functional forces might also lead to fracture after endodontic treatment. This might occur secondary to exposure to erosion, abrasion, physical trauma, and caries. Interventing against these events can be achieved by conducting long follow-up periods and enhancing the endodontic treatment approaches. The current endodontic treatment modalities aim at tissue preservation to enhance resistance to fractures and prevent potential post-treatment complications. In this context, evidence shows the validity of minimally invasive modalities in endodontic treatment with favorable outcomes and reduced frequency of complications. In the present literature review, we have discussed the efficacy of minimally invasive biological treatment in endodontics. It is vital to maintain the integrity of the structures of the tooth-related paracervical area, particularly when treating molars. This is attributed to enhancing the long-term survival rates of the pericervical dentin of these teeth. The current trends represent a revolution in the field of endodontic treatment. This is attributed to the novel development of the various disinfection modalities, which do not need to shape the canal into a round form and induce flaring reactions. Overall, the main advantages of vital pulp therapy include being simple, reduced cost, and reduced risk of treatment-related complications secondary to overcoming the difficulties with the anatomy of the root canals.

Systemic Effects of Selection History on Learned Ignoring

Despite our best intentions, physically salient but entirely task-irrelevant stimuli can sometimes capture our attention. With learning, it is possible to more efficiently ignore such stimuli, although specifically how the visual system accomplishes this remains to be clarified. Using a sample of young-adult participants, we examined the time course of eye movements to targets and distractors. We replicate a reduced frequency of eye movements to the distractor when appearing in a location at which distractors are frequently encountered. This reduction was observed even for the earliest saccades, when selection tends to be most stimulus-driven. When the distractor appeared at the high-probability location, saccadic reaction time was slowed specifically for distractor-going saccades, suggesting a slowing of priority accumulation at this location. In the event that the distractor was fixated, disengagement from the distractor was also faster when it appeared in the high-probability location. Both proactive and reactive mechanisms of distractor suppression work together to minimize attentional capture by frequently-encountered distractors.

Comparative Study of Dynamic Stall between an Aircraft Airfoil and a Wind Turbine Airfoil in an Air–Particle Flow

Dynamic stall in clean air flow has been well studied, but its exploration in air–particle (air–raindrop or air–sand) flow is still lacking. The aerodynamic performance loss of aircraft (NACA0012) and wind turbine (S809) airfoils and their differences during the hysteresis loop at different pitching parameters are also poorly understood. As shown in this paper, the reduced frequency has little effect on the value of the maximum lift coefficient increment caused by particles, but a larger one can enhance the hysteresis effect and drag the angle of attack, at which the maximum increment is obtained, from the up stroke to the down stroke. The large lift coefficient increments of two airfoils and their difference also have a similar change trend with the reduced frequency. Compared to that of NACA0012 airfoil, the increments of S809 airfoil are obviously greater at three mean angles of attack, especially at 8°, which is the commonly used operating angle. In addition, the angle of attack, at which the maximum lift coefficient is obtained, can be significantly changed by particles in two regions: one is under the effect of deep stall, the other is under the effect of light stall at a low, reduced frequency.

Planning for the future: Addressing the spatial accessibility of aged residential care facilities in New Zealand

<p>Evidence in New Zealand suggests that spatial access to aged residential care facilities (ARCFs) has been declining. Poor spatial access to facilities has been shown internationally to lead to reduced frequency of visitation by family and friends, and in turn poorer mental health and wellbeing of people in care. However, the New Zealand population is ageing and older people are increasing as a proportion of the total population. Subsequently, total demand for ARCFs is set to increase dramatically and a substantial number of facilities will likely need to be built by 2026. The intent of this thesis is to explore how geographic information science (GIS) methods can be used to identify potential locations for these ARCFs in New Zealand so that travel time for friends and family is minimised. Providers were surveyed on the relative importance of a series of spatial attributes when deciding where to place new facilities. Maps for each spatial attribute were generated from their preferences and overlaid using weighted linear combination and areas exceeding a suitability threshold were identified as potential locations. To choose optimal locations, maximal covering location-allocation models were used based on projected populations and demand for 2026. The spatial accessibility of these locations was then compared to the spatial accessibility of facilities in 2011. The results suggest that GIS methods have the potential to improve the spatial access to ARCFs to friends and family of people in care.</p>

Planning for the future: Addressing the spatial accessibility of aged residential care facilities in New Zealand

<p>Evidence in New Zealand suggests that spatial access to aged residential care facilities (ARCFs) has been declining. Poor spatial access to facilities has been shown internationally to lead to reduced frequency of visitation by family and friends, and in turn poorer mental health and wellbeing of people in care. However, the New Zealand population is ageing and older people are increasing as a proportion of the total population. Subsequently, total demand for ARCFs is set to increase dramatically and a substantial number of facilities will likely need to be built by 2026. The intent of this thesis is to explore how geographic information science (GIS) methods can be used to identify potential locations for these ARCFs in New Zealand so that travel time for friends and family is minimised. Providers were surveyed on the relative importance of a series of spatial attributes when deciding where to place new facilities. Maps for each spatial attribute were generated from their preferences and overlaid using weighted linear combination and areas exceeding a suitability threshold were identified as potential locations. To choose optimal locations, maximal covering location-allocation models were used based on projected populations and demand for 2026. The spatial accessibility of these locations was then compared to the spatial accessibility of facilities in 2011. The results suggest that GIS methods have the potential to improve the spatial access to ARCFs to friends and family of people in care.</p>