bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supralinear dendritic Ca2+ signalling in young developing CA1 pyramidal cells
Authors: Pohle Jörg , Bischofberger Josef 
Published: September 2014

Key points
Because intracellular Ca2+ is important for activity‐dependent growth and development, we studied action potential (AP)‐evoked dendritic Ca2+ influx and Ca2+ buffering in developing rat CA1 pyramidal cells during the first 1–4 weeks after birth.
We show for the first time that active dendritic backpropagation of APs generates large Ca2+ transients in pyramidal cell dendrites even after the first postnatal week.
The amplitude of Ca2+ transients at 1 week is similar to that at 4 weeks because a four‐fold upregulation of calcium influx per AP is balanced by a similar increase in endogenous Ca2+ buffer capacity during this period.
The calcium extrusion after APs was about five times slower at 1 week than at 4 weeks, resulting in a slower decay in young cells and a more effective temporal summation during brief bursts of APs.
During continuous theta‐burst firing, dendritic calcium concentration was up to three‐fold larger in animals aged 1 week than in those aged 4 weeks, generated via an activity‐dependent slow‐down of Ca2+ extrusion, which may allow Ca2+‐dependent control of growth and development with a large dynamic range.AbstractAlthough Ca2+ is critically important in activity‐dependent neuronal development, not much is known about the regulation of dendritic Ca2+ signals in developing neurons. Here, we used ratiometric Ca2+ imaging to investigate dendritic Ca2+ signalling in rat hippocampal pyramidal cells during the first 1–4 weeks of postnatal development. We show that active dendritic backpropagation of Nav channel‐dependent action potentials (APs) evoked already large dendritic Ca2+ transients in animals aged 1 week with amplitudes of ∼150 nm, similar to the amplitudes of ∼160 nM seen in animals aged 4 weeks. Although the AP‐evoked dendritic Ca2+ load increased about four times during the first 4 weeks, the peak amplitude of free Ca2+ concentration was balanced by a four‐fold increase in Ca2+ buffer capacity κs (∼70 vs. ∼280). Furthermore, Ca2+ extrusion rates increased with postnatal development, leading to a slower decay time course (∼0.2 s vs. ∼0.1 s) and more effective temporal summation of Ca2+ signals in young cells. Most importantly, during prolonged theta‐burst stimulation dendritic Ca2+ signals were up to three times larger in cells at 1 week than at 4 weeks of age and much larger than predicted by linear summation, which is attributable to an activity‐dependent slow‐down of Ca2+ extrusion. As Ca2+ influx is four‐fold smaller in young cells, the larger Ca2+ signals are generated using four times less ATP consumption. Taken together, the data suggest that active backpropagations regulate dendritic Ca2+ signals during early postnatal development. Remarkably, during prolonged AP firing, Ca2+ signals are several times larger in young than in mature cells as a result of activity‐dependent regulation of Ca2+ extrusion rates.
Potential Impact of Renewable Fuels and Technological Innovations on Global Air Traffic Emissions Development by 2050
Authors: Wolters Florian , Schaefer Martin , von der Bank Ralf 
Published: September 2014

The aviation industry has set ambitious reduction targets for future air traffic emissions to compensate for the environmental impact of increasing air transport. Besides technological innovation in the fields of aircraft and engine technology, alternative fuels from non-petroleum feedstock are often seen as having long-term potential to offer reductions in aviation’s greenhouse gas emissions. The current paper studies the effects of potential emission reduction measures up to the year 2050, taking technology developments as well as renewable fuel scenarios into account. The individual impacts of both contributions are assessed in terms of fuel burn, direct CO2 emissions, and life cycle CO2eq emissions. The results are compared to the agreed mid and long term reductions targets, i.e. carbon-neutral growth by 2020 and halving CO2 emissions by 2050.
Future air traffic emissions are evaluated based on one reference scenario and three technology scenarios, derived from the ICAO global fuel burn forecast and Flightpath 2050 technology improvement goals. Four renewable fuel penetration scenarios are considered and the impact of alternative renewable fuels in terms of Synthetic Paraffinic Kerosene (SPK) on fuel burn and direct CO2 emissions are taken into consideration. Moreover, to account for the fuels’ life cycle emissions three different life cycle CO2eq emission reduction potentials scenarios are applied.
This study provides a quantitative view on exponential growth of aviation fleet CO2 emissions. The potential of individual contributions are explicitly highlighted and potential developments in air traffic emissions are quantified. The results show that in addition to significant efficiency improvements in aircraft and engine technology, a high renewable fuel share will be required to compensate for steady air traffic growth and to achieve carbon neutral growth from 2020 onwards and a 50% CO2eq emission reduction by 2050.
Multipoint Multi-Objective Optimization of a Low Solidity Circular Cascade Diffuser in Centrifugal Blowers
Authors: Sakaguchi Daisaku , Ishida Masahiro , Hayami Hiroshi , Mueller Lasse , Alsalihi Zuheyr , Verstraete Tom 
Published: September 2014

In radial compressors or blowers, a low solidity circular cascade diffuser (LSD) is one of the effective devices to improve the pressure recovery at design flow rate while guaranteeing a wide operating range. The improvement is mainly attributed to the so called secondary flow effect, which reduces the flow separation on the LSD blade at small flow rates. However, it is very difficult to find out the effective shape of the blade in order to promote this secondary flow effect. In this paper, a multipoint and multi-objective optimization technique is applied to design the LSD blade of a centrifugal blower. The optimization method has been developed at the von Karman Institute for Fluid Dynamics (VKI), which makes use of an evolutionary algorithm, a metamodel as a rapid exploration tool, and a high fidelity 3D Navier-Stokes solver.
The optimization is aiming at improving the static pressure coefficient at design point and at low flow rate condition while constraining the slope of the lift coefficient curve. Seven detailed design parameters describing the shape and position of the LSD vane were introduced, e.g. the radial spacing between impeller exit and the LSD leading edge, the radial chord length and the mean camber angle distribution of the LSD blade with five control points. Moreover, a small tip clearance of the LSD blade was applied in order to activate and to stabilize the secondary flow effect at small flow rate condition. The optimized LSD blade has an extended operating range of 114 % towards smaller flow rate as compared to the baseline design without deteriorating the diffuser pressure recovery at design point. The diffuser pressure rise and operating flow range of the optimized LSD blade are experimentally verified. It is found that the optimized LSD blade shows good improvement of the blade loading in the whole operating range, while at small flow rate the flow separation on the LSD blade has been successfully suppressed by the secondary flow effect. This is fully corresponding to the CFD predictions and demonstrates the effectiveness of the optimization methodology, by limiting the experimental testing to only two geometries.
Enhanced Robust Design Simulation and Application to Engine Cycle and Technology Design
Authors: Sands Jonathan S. , Perullo Christopher A. , Kestner Brian K. , Mavris Dimitri N. 
Published: September 2014

Increases in computing power have enabled designers to efficiently use Monte Carlo simulation to perform robust design analyses of engine systems. Unfortunately, the designer is now faced with the problem of being able to generate more data than he is capable of analyzing or understanding in any tractable manner. Traditional filtered Monte Carlo methods involve creating surrogate model representations (such as Artificial Neural Networks) of a physics based model in order to rapidly generate tens of thousands of model responses as design and technology input parameters are randomly varied within user defined distributions. The downside to this approach is that the designer is often faced with a large design space with which he must perform a significant amount of post processing to arrive at probabilities of meeting design requirements.
This research enhances the traditional filtered Monte Carlo robust design approach by regressing surrogate responses of joint confidence intervals for metric responses of interest. Fitting surrogate responses of probabilistic confidence intervals rather than the raw response data changes the problem the engineer is able to answer. Using the new approach the question can be better phrased in terms of the probability of meeting certain requirements. For example, one will be able to ask, “What engine overall pressure ratio is needed to achieve a 90% chance of reaching a 25% reduction in TSFC from the current state of the art?” The more traditional approach does not have the ability to include confidence in the process without significant post-processing.
The process will be demonstrated using a two-spool axi-centrifugal turboshaft architecture modeled using the Numerical Propulsion System Simulation (NPSS) program. The new robust design process will be used to demonstrate the probabilistic impacts of both technology and design variables on choosing a cycle that is robust to both growth in mission requirements and changes in anticipated technology levels as the design matures. More specifically, the research will present engine cycle variables including component pressure ratios and temperatures that provide for high probability of meeting notional system level requirements, such as ESFC, under different levels of technology uncertainty. Technology uncertainty will be defined in terms of available material properties and component efficiency.
The Effect of Proximity on Park and Beach Use and Physical Activity Among Rural Adolescents
Authors: Edwards Nicole Joy , Giles-Corti Billie , Larson Ann , Beesley Bridget 
Published: September 2014

Background:Associations between access to environments and levels of physical activity (PA) among adolescents have been established; however the influence of neighborhood design barriers (eg, major roads) on these relationships is less understood.Methods:In 2006, adolescents (n = 1304) in rural Western Australia completed the Up4it Physical Activity Survey measuring frequency and duration of organized and nonorganized physical activity by season. Geographic Information Systems (GIS) were used to objectively measure distance to nearest park and beach and busy road barriers en route to these destinations.Results:Proximity to parks and beaches was associated with use of these environments for PA among adolescents, but this relationship attenuated after adjustment for presence of a major road. Park and beach use was positively associated with achieving recommended levels of PA. Paradoxically, proximity to these environments was not associated with achieving recommended levels of PA. Results suggest access to parks and beaches is necessary but may be insufficient to achieve recommended levels of PA. These relationships varied by season.Conclusions:Strategies should be put in place to encourage use of proximate supportive environments. Planning neighborhoods to reduce barriers to access and interventions to overcome seasonal variations in behavior may improve participation levels among adolescents.
Smoking Impact on Grip Strength and Fatigue Resistance: Implications for Exercise and Hand Therapy Practice
Authors: Al-Sayegh Nowall , Al-Obaidi Saud , Nadar Mohammed 
Published: September 2014

Background:Grip strength assessment reflects on overall health of the musculoskeletal system and is a predictor of functional prognosis and mortality. The purpose of this study was: examine whether grip-strength and fatigue resistance are impaired in smokers, determine if smoking-related impairments (fatigue-index) can be predicted by demographic data, duration of smoking, packets smoked-per-day, and physical activity.Methods:Maximum isometric grip strength (MIGS) of male smokers (n = 111) and nonsmokers (n = 66) was measured before/after induced fatigue using Jamar dynamometer at 5-handle positions. Fatigueindex was calculated based on percentage change in MIGS initially and after induced fatigue.Results:Number of repetitions to squeeze the soft rubber ball to induce fatigue was significantly lower in smokers compared with nonsmokers (t = 10.6, P < .001 dominant hand; t = 13.9, P < .001 nondominant), demonstrating a significantly higher fatigue-index for smokers than nonsmokers (t = –8.7, P < .001 dominant hand; t = –6.0, P < .001 nondominant). The effect of smoking status on MIGS scores was significantly different between smokers and nonsmokers after induced fatigue (β = –3.98, standard error = 0.59, P < .001) where smokers experienced on average a reduction of nearly 4 MIGS less than nonsmokers before fatigue. Smoking status was the strongest significant independent predictor of the fatigue-index.Conclusions:Smokers demonstrated reduced grip strength and fast fatigability in comparison with nonsmokers.
Expert Approaches to Promote Adolescent Physical Activity in Iran: Development of the Promoting Strategies Using the Nominal Group Technique Meeting
Authors: Baheiraei Azam , Hamzehgardeshi Zeinab , Mohammadi Mohammad Reza , Mohammadi Eesa , Vedadhir AbouAli 
Published: September 2014

Background:Several studies have shown that physical activity decreases as the age increases. This study was for evaluating the perspectives of health sciences specialists or informants on the strategies for increasing physical activity among Iranian adolescents using Nominal Group Technique (NGT).Methods:a semiquantitative/qualitative methodology research using NGT for prioritizing the strategies for alleviating the physical activities among Iranian adolescents based on the opinions of health sciences experts. This study conducted in Tehran, Iran, 2011.Results:Overall, 16 items received scores from 2–29 and were further listed as the accepted strategies for promoting physical activity among adolescents. The most and least recommended strategies were respectively in the categories of school, neighborhood and family. This study findings show ‘the constructionist activities or strategies (eg, claim-making, image-making, myth-constructing and framing) among adolescents using main claim-makers of Iranian society, including the state-sponsored media.,’ received the highest score by all the participants of NGT.Conclusions:The interesting finding of this study is the special view point of the specialists to role of socioecological factors in promoting physical activity in the context of Iranian society.
Durations and Domains of Daily Aerobic Activity: Evidence From the 2010 Canadian Time-Use Survey
Authors: Millward Hugh , Spinney Jamie E. L. , Scott Darren 
Published: September 2014

Background:This study employs national time-diary data to evaluate how much aerobic activity Canadians engage in on a daily basis, how that activity is apportioned by activity domain, and how subgroups within the population vary in their aerobic attainment.Methods:The study employs time-use data from the 2010 General Social Survey of Canada, for 15,390 respondents aged 15 and older. To estimate effort levels, the authors harmonized survey codes with those in the Compendium of Physical Activities. Aerobic activity was defined as moderate or vigorous effort at 3.5 Metabolic Equivalent of Task (MET) or higher.Results:Among the 4 activity domains, aerobic participation is highest in leisure activities, followed by chores, paid work, and active transportation (AT). Only a minority (42%) of respondents recorded at least 20 mins/day of aerobic activity. Aerobic totals were particularly low for women and those in poor or fair health, and low for students, 15- to 24-year-olds, and those residing in Quebec, Ontario, and larger cities.Conclusions:The majority of Canadian adults are failing to meet recommended aerobic activity levels. However, there is considerable opportunity to increase aerobic participation for some groups, particularly women and young adults, especially in the leisure and AT domains.
Designing Active Communities: A Coordinated Action Framework for Planners and Public Health Professionals
Authors: Bergeron Kim , Lévesque Lucie 
Published: September 2014

Background:Community design can have a positive or negative influence on the physical activity level of residents. The complementary expertise of professionals from both planning and public health is needed to build active communities. The current study aimed to develop a coordinated framework for planners and public health professionals to enhance the design of active communities.Methods:Planners and public health professionals working in Ontario, Canada were recruited to participate in a concept mapping process to identify ways they should work together to enhance the design of active communities.Results:This process generated 72 actions that represent collaborative efforts planners and public health professionals should engage in when designing active communities. These actions were then organized by importance and feasibility. This resulted in a coordinated action framework that includes 19 proximal and 6 distal coordinated actions for planners and public health professionals.Conclusion:Implementation of the recommended actions has the potential to make a difference in community design as a way to enhance physical activity in community members. This Coordinated Action Framework provides a way to address physical inactivity from an environmental and policy standpoint.
Supportive Environments for Physical Activity, Community Action, and Policy in 8 European Union Member States: Comparative Analysis and Specificities of Context
Authors: Ruetten Alfred , Frahsa Annika , Engbers Luuk , Gusi Narcis , Mota Jorge , Pacenka Rimantas , Troelsen Jens , Vasickova Jana , Vuillemin Anne 
Published: September 2014

Background:A multilevel theoretical framework of physical activity (PA) promotion that addresses supportive environments, PA behavior, community action, and PA promoting policies is related to research and development in an international comparative study.Methods:Most-different and most-similar case selection was applied to data from 8 European Union Member States. Data from semistructured key informant qualitative interviews, focus group interviews with experts and policy-makers, as well as document analysis were linked to corresponding Eurobarometer data.Results:The framework on the interplay of environment, PA behavior, community action and policies appears to be working across most different countries. Comprehensive systems of PA infrastructures are interlinked with relatively high levels of PA prevalence. These countries implement comprehensive national policies on PA promotion and show a positive perception of related local governments’ engagement. Less comprehensive systems of infrastructures interplay with lower levels of PA prevalence, less community action and fewer policies. Differences between similar cases are linked to country-specific contexts.Conclusions:Framework application and comparative analysis indicates how to relate theory to empirical research and complex data sets. In-depth analysis of country-specific contexts and longitudinal observation on changes within and between countries might advise on how to integrate the framework into intervention research.
Considering Sport Participation as a Source for Physical Activity Among Adolescents
Authors: Pharr Jennifer , Lough Nancy L. 
Published: September 2014

Background:Studies have shown participation in sport is lower among girls than boys, decreases as students matriculate through high school, is lowest among Black and Hispanic girls and has a positive relationship with SES. With sport recognized as a contributor to physical activity and health in adolescents, consideration of diminishing rates of participation appears warranted. The purpose of this study was to identify patterns related to differences in self-reported sport participation between genders, ethnic groups, grades and SES.Methods:This study was a cross-sectional, secondary analysis of data collected for a sport interest survey. All students in grades 8–11 attending middle and high schools were provided an opportunity to participate in the survey. Data from 49,832 students were analyzed.Results:Among the participants, Black girls participated more and White girls participated less than expected. Black boys participated more while White and Asian boys participated less than expected. Reported sport participation was high compared with national data when analyzed by gender and ethnic group. Sport participation was higher in low SES schools compared with high SES schools.Conclusion:The importance of sport as a source of physical activity in underserved groups is significant.
Should Physical Activity Intervention Efforts Take a Whole Population, High-Risk, or Middle Road Strategy?
Authors: Peeters Geeske , Hockey Richard , Brown Wendy 
Published: September 2014

Purpose:This study was designed to compare theoretical strategies for changing physical activity (PA) in terms of their potential to reduce the incidence of chronic conditions in midage women: (1) whole population: +30 minutes/week in all, (2) high-risk: +60 minutes/week in the lowest 25% of the PA distribution, and (3) middle road: shift all those not meeting guidelines to a level commensurate with meeting guidelines.Methods:10,854 participants (50–55 years in 2001) in the Australian Longitudinal Study of Women’s Health completed mail surveys in 2001, 2004, 2007, and 2010. PA was calculated as MET·minutes/week spent in walking, moderate and vigorous PA in the previous week. Incidence rates per 1000 person-years for diabetes, heart disease, hypertension, cancer, and depression were calculated for the actual distribution and after modeled shifts in PA.Results:The incidence rates were 10.6 for diabetes, 7.0 for heart disease, 30.7 for hypertension, 8.0 for cancer, and 28.4 for depression. Greater reductions in incidence were found for the middle road strategy than for the whole population and high-risk strategies, with reductions ranging from –6.3% for cancer to –12.3% for diabetes.Discussion:This theoretical modeling showed that a middle road strategy to increasing PA was superior to the whole population and high-risk strategies, in terms of reducing incidence rates of chronic conditions in middle-aged women.
Does Daylight Savings Time Encourage Physical Activity?
Authors: Zick Cathleen D. 
Published: September 2014

Background:Extending Daylight Savings Time (DST) has been identified as a policy intervention that may encourage physical activity. However, there has been little research on the question of if DST encourages adults to be more physically active.Methods:Data from residents of Arizona, Colorado, New Mexico, and Utah ages 18–64 who participated in the 2003–2009 American Time Use Survey are used to assess whether DST is associated with increased time spent in moderate-to-vigorous physical activity (MVPA). The analysis capitalizes on the natural experiment created because Arizona does not observe DST.Results:Both bivariate and multivariate analyses indicate that shifting 1 hour of daylight from morning to evening does not impact MVPA of Americans living in the southwest.Conclusions:While DST may affect the choices people make about the timing and location of their sports/recreational activities, the potential for DST to serve as a broad-based intervention that encourages greater sports/recreation participation is not supported by this analysis. Whether this null effect would persist in other climate situations is an open question.