Perceived barriers to commuter and exercise bicycling in U.S. adults: The 2017 National Household Travel Survey

Introduction: Bicycling is a type of physical activity associated with positive health outcomes, but many barriers exist to regular bicycling for recreation and transportation. The objective of this study was to describe self-reported barriers to bicycling overall, and by bicycling domain, among a national sample of persons aged 16 and above that reported bicycling outside in the past week. Methods: This analysis, conducted in 2019, utilized data from the United States (US) Department of Transportation's 2017 National Household Travel Survey (NHTS). Weighted point estimates and 95% confidence intervals were calculated for reported barriers to bicycling by category of bicyclist: exercise-exclusive, multi-use, and commuter. Results: The final analytic sample was 18,189, representing approximately 7% of the US population (N = 20,911,680). Barriers that prevented bicycling more was reported by 37.9% of the US population of adult bicyclists (95% CI 37.2, 38.6). Barriers related to safety were more commonly reported (31.9% of total bicyclists), compared to barriers related to infrastructure (22.1% of total bicyclists). Safety-related barriers were more commonly reported among multi-use bicyclist (33.7% vs. 30.9% of exercise-exclusive). Commuter bicyclists reported infrastructure barriers the least (13.9% vs. 22.7% of exercise-exclusive). The most commonly reported single barrier to bicycling more, regardless of bicycling category, was heavy traffic (10.3% of total bicyclists), followed by no nearby paths or trails (7.6% of total bicyclists). Overall, distribution of individual barriers was similar across categories of bicyclists: exercise-exclusive, multi-use, and commuter. Conclusions: Heavy traffic and lack of separated paths or trails were the most frequently identified barriers to bicycling more. Communities wishing to promote bicycling for transportation, recreation, or both should consider how traffic reduction strategies and changes in the built environment could make bicycling safer and more accessible

Feeding and Distribution of Porosity in Cast Al-Si Alloys as Function of Alloy Composition and Modification

Unmodified, Na-modified, and Sr-modified castings of Al-7 pct Si and Al-12.5 pct Si alloys were cast in molds in which it was possible to create different cooling conditions. It is shown how solidification influences the distribution of porosity at the surface and the center of the castings as a function of modification and Si content in sand- and chill-cast samples. Eutectic modification, Si content, and cooling conditions have a great impact on the distribution of porosity. Unmodified and Na-modified castings are more easily fed with porosity tending to congregate near the centerline of the casting, while Sr-modified castings solidify in a mushy manner that creates a more homogeneous distribution of porosity in the casting. The amount of porosity was highest in the Sr-modified alloys, lower in the Na-modified alloys, and lowest in the unmodified alloys. The size of the porosity-free layer and the effectiveness of the feeders were greater in the castings made with the steel chills due to the increased thermal gradients and consequent increase in the directionality of solidification

Quantity and Fate of Water Salvage as a Result of Saltcedar Control on the Pecos River in Texas

This report presents results for the Subtask 3.3 of the Pecos River Basin Assessment Project sponsored by the U.S. Environmental Protection Agency (EPA) and the Texas State Soil and Water Conservation Board (TSSWCB). The overall objective of Subtask 3.3 is to examine the hydrologic impacts of Tamarix spp. (saltcedar) control along a 5 km segment of the Pecos River near Mentone, Texas. This report is also based on work supported in part by the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Agreements No. 2005-34461-15661 and No. 2005-45049-03209, Texas Cooperative Extension (TCE), and Texas Agricultural Experiment Station (TAES). As part of the deliverables of this project, an existing monitoring network of 8 wells was examined and enhanced with 9 additional wells equipped with water level loggers. Land surface profile and piezometric surface profile were developed to characterize interaction of surface and groundwater for different seasons as well as for verification of monitored water levels. Flow measurements were conducted during a release of water from Red Bluff Reservoir in March 2005 to determine losses or gains within the selected reach. Continued water level monitoring data provide more detailed information about water exchange between surface water and groundwater under different flow conditions. Correlation analyses of river stage and groundwater levels in monitoring boreholes provided further insight. Results show that the river is hydraulically connected with shallow groundwater for this 5 km segment, which is comprised of Sites A and B, near Mentone, Texas in Loving County. Generally, the river is losing water to the aquifer at both sites. A gentle hydraulic gradient exists on the east bank of the river while a steeper gradient occurs on the west bank probably due to different hydrological properties of soils. Seepage from the river not only recharges the shallow aquifer, but also creates groundwater flow parallel to the channel, which may eventually discharge back to the river downstream. The reversed hydraulic gradients also demonstrate complexity of the dynamic relationship between the river and the aquifer. Water loss at the treated Site A decreased dramatically following saltcedar control in 2001, and remained very low through 2004. This study conservatively estimates water salvage of 0.5 – 1.0 acre feet per acre from control of saltcedar at this particular site. Salvaged water most likely contributes to aquifer recharge rather than increased streamflow. Vegetation return in the form of native grasses and saltcedar re-growth at Site A may be the cause of corresponding increases in water loss in 2005 and 2006. Site A may also be affected by the untreated adjacent upriver segment (Site B), resulting in over-estimated water loss. Although the saltcedar water loss and salvage estimates presented here are believed to be conservative, the extreme differences in yearly site conditions throughout the study made it difficult to compare pre and post treatment calculations with confidence. It is recommended that additional flow measurements for longer reaches, enhanced monitoring of surface water and groundwater interaction, and further studies on hydrological impacts of saltcedar control be conducted. For future studies using the paired plot method, it is recommended that both sites be logged for at least 3 years prior to treatment. To reduce the potential for upriver treatment affect on downriver study areas, it is recommended that hydrological and ecological conditions immediately upstream of each plot be alike.U.S. Environmental Protection Agency and the Texas State Soil and Water Conservation Boar

Study of heterogeneous nucleation of eutectic Si in high-purity Al-Si alloys with Sr addition

The official published version can be accessed from the link below - Copyright @ 2010 The Minerals, Metals & Materials Society and ASM InternationalAl-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodynamic calculations, and transmission electron microscopy techniques were employed to examine the effect of the Sr and P additions on eutectic undercoolings and nucleation phenomenon. Results indicate that, unlike P, Sr does not promote nucleation. Increasing Sr additions depressed the eutectic nucleation temperature. This may be a result of the formation of a Sr phase that could consume or detrimentally affect potent AlP nucleation sites.This work is financially supported by the Higher Education Commission of Pakistan and managerially supported from the OAD

Investment under ambiguity with the best and worst in mind

Recent literature on optimal investment has stressed the difference between the impact of risk and the impact of ambiguity - also called Knightian uncertainty - on investors' decisions. In this paper, we show that a decision maker's attitude towards ambiguity is similarly crucial for investment decisions. We capture the investor's individual ambiguity attitude by applying alpha-MEU preferences to a standard investment problem. We show that the presence of ambiguity often leads to an increase in the subjective project value, and entrepreneurs are more eager to invest. Thereby, our investment model helps to explain differences in investment behavior in situations which are objectively identical

Probing the unparticle signal in b→db \to d penguin processes

We investigate the effect of unparticles in the pure $b \to d$ penguin processes $B^0 \to K^0 \bar K^0$ and $B^{+,0} \to \phi \pi^{+,0}$. Since these processes receive dominant contributions due to the {\it top} quark in the loop, direct and mixing-induced CP asymmetry parameters in these processes are expected to be vanishingly small in the standard model. We find that due to the unparticle effect sizable nonzero CP violation could be possible in these channels.Comment: 12 pages, 4 figures, version to appear in Phys. Lett.

Sire contribution to fertilization failure and early embryo survival in cattle

peer-reviewedDespite passing routine laboratory tests of semen quality, bulls used in artificial insemination (AI) exhibit a significant range in field fertility. The objective of this study was to determine whether subfertility in AI bulls is due to issues of sperm transport to the site of fertilization, fertilization failure, or failure of early embryo or conceptus development. In experiment 1, Holstein-Friesian bulls (3 high fertility, HF, and 3 low fertility, LF) were selected from the national population of AI bulls based on adjusted fertility scores from a minimum of 500 inseminations (HF: +4.37% and LF: −12.7%; mean = 0%). Superovulated beef heifers were blocked based on estimated number of follicles at the time of AI and inseminated with semen from HF or LF bulls (n = 3–4 heifers per bull; total 19 heifers). Following slaughter 7 d later, the number of corpora lutea was counted and the uteri were flushed. Recovered structures (oocytes/embryos) were classified according to developmental stage and stained with 4′,6-diamidino-2-phenylindole to assess number of cells and accessory sperm. Overall recovery rate (total structures recovered/total corpora lutea) was 52.6% and was not different between groups. Mean (± standard error of the mean) number of embryos recovered per recipient was 8.7 ± 5.2 and 9.4 ± 5.5 for HF and LF, respectively. Overall fertilization rate of recovered structures was not different between groups. However, more embryos were at advanced stages of development (all blastocyst stages combined), reflected in a greater mean embryo cell number on d 7 for HF versus LF bulls. Number of accessory sperm was greater for embryos derived from HF than for LF bulls. The aim of experiment 2 was to evaluate the effect of sire fertility on survival of bovine embryos to d 15. Day 7 blastocysts were produced in vitro using semen from the same HF (n = 3) and LF (n = 3) bulls and transferred in groups of 5–10 to synchronized heifers (n = 7 heifers per bull; total 42 heifers). Conceptus recovery rate on d 15 was higher in HF (59.4%,) versus LF (45.0%). Mean length of recovered conceptuses for HF bulls was not affected by fertility status. In conclusion, while differences in field fertility among AI sires used in this study were not reflected in fertilization rate, differences in embryo quality were apparent as early as d 7. These differences likely contributed to the higher proportion of conceptuses surviving to d 15 in HF bulls

P-EdgeCoolingMode: An Agent Based Performance Aware Thermal Management Unit for DVFS Enabled Heterogeneous MPSoCs

Thermal cycling as well as spatial and thermal gradient affects the lifetime reliability and performance of heterogeneous multiprocessor systems-on-chips (MPSoCs). Conventional temperature management techniques are not intelligent enough to cater for performance, energy efficiency as well as operating temperature of the system. In this paper we propose a light-weight novel thermal management mechanism (P-EdgeCoolingMode) in the form of intelligent software agent, which monitors and regulates the operating temperature of the CPU cores to improve reliability of the system while catering for performance requirements. P-EdgeCoolingMode is capable of pro-actively monitoring performance and based on the user’s demand the agent takes necessary action, making the proposed methodology highly suitable for implementation on existing as well as conceptual Edge devices utilizing heterogeneous MPSoCs with dynamic voltage and frequency scaling (DVFS) capabilities. We validated our methodology on the Odroid-XU4 MPSoC and Huawei P20 Lite (HiSilicon Kirin 659 MPSoC). P-EdgeCoolingMode has been successful to reduce the operating temperature while improving performance and reducing power consumption for chosen test cases than the state-of-the-art. For applications with demanding performance requirement P-EdgeCoolingMode has been found to improve the power consumption by 30.62% at the most in comparison to existing state-of-the-art power management methodologies

Some Consequences of Thermosolutal Convection: The Grain Structure of Castings

The essential principles of thermosolutal convection are outlined, and how convection provides a transport mechanism between the mushy region of a casting and the open bulk liquid is illustrated. The convective flow patterns which develop assist in heat exchange and macroscopic solute segregation during solidification; they also provide a mechanism for the transport of dendritic fragments from the mushy region into the bulk liquid. Surviving fragments become nuclei for equiaxed grains and so lead to blocking of the parental columnar, dendritic growth front from which they originated. The physical steps in such a sequence are considered and some experimental data are provided to support the argument