Independent Effect of Heat Stress During Exercise on Arterial Stiffness

Context: Cardiovascular disease (CVD) is one of the leading causes of mortality in the United States, accounting for about 1 in every 3 deaths annually. While studies have shown that arterial stiffness, a leading precursor to CVD, improves with passive heat stress not much is known about the independent effect of heat stress during exercise on arterial stiffness. Objective: The objective of this study was to examine the independent effect of heat stress during exercise on arterial stiffness. Design: Participants visited the lab three times; one familiarization and two experimental trials. Experimental trials were randomized and counter-balanced. Setting: All trials occurred in the Human Performance Laboratory at the University of Arkansas, Fayetteville. The experimental trials consisted of subjects cycling at ~50% of their maximum aerobic capacity in an environment of 40°C / 40% relative humidity (Heat Cycle) or 15°C / 30% relative humidity (Cool Cycle). Participants: Participants included five male subjects and four female subjects. Subjects were older individuals (Age = 49 ± 12 y, Body Mass = 66.71 ± 12.64 kg) with stiffer arteries at baseline (\u3e 6 m/s) identified in the familiarization trial. Interventions: The intervention was environmental condition; one trial occurred at 40°C / 40% relative humidity (Heat Cycle) and the other at 15°C / 30% relative humidity (Cool Cycle). Since the participants are exercising in both trials at the same aerobic capacity, we can elucidate the independent effect that mean body temperature (i.e., heat stress) had on arterial stiffness during exercise. Main Outcome Measures: Before and after cycling, pulse wave velocity (PWV measures occurred via ultrasound at the tibial, radial, femoral and carotid artery sites) were used to assess arterial stiffness. Specifically, central arterial stiffness was assessed by using measures between the carotid and femoral artery sites, while peripheral stiffness was assessed using the radial and tibial artery sites. At the same time, mean body temperature (Tbody) was measured via skin and rectal thermistors. Results: Tbody at the end of exercise showed significant differences between the heat cycle and cool cycle trials respectively (36.47 ± 0.23 vs. 34.84 ± 0.40°C). There were no interactions between time and condition for central PWV for Heat Cycle and Cool Cycle respectively (100.02 ± 138.64 vs. 24.19 ± 82.40 cm/s, p = 0.38), upper peripheral PWV (47.76 ± 131.35 vs. 64.41 ± 109.99 cm/s, p = 0.56) and lower peripheral PWV (40.77 ± 142.96 vs. 3.77 ± 167.67 cm/s, p = 0.47). Conclusions: The findings of this study suggest that differences in mean body temperature do not result in significant differences in arterial stiffness following exercise

An investigation of the relationships among the family of origin, need for achievement, and career development

The study was designed to examine, from a family system theory and a contextual approach, the impact of family environment on career thoughts, career indecision, and vocational identity. It further expanded career development research to include the need for achievement by examining the relationship between need for achievement and career-related variables. A sample of 211 undergraduate college students was administered the Family Environment Scale, Career Decision Scale, Career Thoughts Inventory, My Vocational Situation, and Personal Values Questionnaire. The results revealed a limited relationship between the family of origin and career development outcome measures. Specifically, independence and expressiveness in the family of origin environment were positively related to vocational identity. Independence was also negatively related to career indecision. Thus, some aspects of the family environment were shown to be important in career development. Career thoughts were shown to be important factors that influence an individual\u27s career decision-making process and overall vocational development. Dysfunctional career thoughts (commitment anxiety, decision-making confusion, and external conflict) mediated some relationships among family environment variables, career indecision, and vocational identity. Need for achievement was not found to be related to career indecision or vocational identity. Though additional research is suggested, the need for achievement was not shown to be a salient factor in career development. Overall, the results of the study suggested that there are different mechanisms interacting between individual (e.g., dysfunctional career thoughts) and contextual factors (e.g., family expressiveness) that influence career decision making and the development of vocational identity

Long-term survival in lung transplant recipients after successful preoperative coronary revascularization

ObjectiveCoronary artery disease is considered a contraindication to lung transplantation. We studied effect of pre-lung transplantation nonobstructive coronary artery disease and revascularized coronary artery disease on long-term lung transplant survival.MethodsClinical courses of 172 lung transplant recipients from December 1990 to May 2003 were reviewed. Significant coronary artery disease, defined as left main stenosis of greater than 50% or other epicardial vessel stenosis of greater than 70%, was present in 7 patients; 6 received percutaneous coronary intervention and 1 received coronary artery bypass grafting before transplantation.ResultsGroups were similar with regard to sex, race, or length of intensive care days. The group with normal coronary arteries was significantly younger than the groups with coronary artery disease. The revascularized group had a significant increase in dysrhythmias (P < .003) and 1-, 3-, and 5-year survivals of 85%, 85%, and 69%, respectively. Those with insignificant coronary artery disease (14 patients) demonstrated a 1-, 3-, and 5-year survival of 64%, 40%, and 32%, respectively. The normal coronary group (151 patients) had a 1-, 3-, and 5-year survival of 75%, 58%, and 40%, respectively. The revascularized group had a significant survival advantage compared with that of the insignificant coronary artery disease group (P < .04, log-rank test).ConclusionLong-term survival of lung transplant recipients with revascularized coronary arteries is similar to that of subjects with normal coronary arteries, despite an increased incidence of dysrhythmias. Lung transplant recipients with insignificant coronary artery disease had a worse survival than the revascularized group. More studies are needed to ascertain the cause and determine the optimal management for lung transplant recipients with insignificant coronary artery disease

Simulating the influences of groundwater on regional geomorphology using a distributed, dynamic, landscape evolution modelling platform

A dynamic landscape evolution modelling platform (CLiDE) is presented that allows a variety of Earth system interactions to be explored under differing environmental forcing factors. Representation of distributed surface and subsurface hydrology within CLiDE is suited to simulation at sub-annual to centennial time-scales. In this study the hydrological components of CLiDE are evaluated against analytical solutions and recorded datasets. The impact of differing groundwater regimes on sediment discharge is examined for a simple, idealised catchment, Sediment discharge is found to be a function of the evolving catchment morphology. Application of CLiDE to the upper Eden Valley catchment, UK, suggests the addition of baseflow-return from groundwater into the fluvial system modifies the total catchment sediment discharge and the spatio-temporal distribution of sediment fluxes during storm events. The occurrence of a storm following a period of appreciable antecedent rainfall is found to increase simulated sediment fluxes

Epidemiology and survival of the five stages of chronic kidney disease in a systolic heart failure population

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102653/1/ejhfhfq077.pd

Retrieval of vegetative fluid resistance terms for rigid stems using airborne lidar.

Hydraulic resistance of riparian forests is an unknown but important term in flood conveyance modeling. Lidar has proven to be a very important new data source to physically characterize floodplain vegetation. This research outlines a recent campaign that aims to retrieve vegetation fluid resistance terms from airborne laser scanning to parameterize trunk roughness. Information on crown characteristics and vegetation spacing can be extracted for individual trees to aid in the determining of trunk stem morphology. Airborne lidar data were used to explore the potential to characterize some of the prominent tree morphometric properties from natural and planted riparian poplar zones such as tree position, tree height, trunk location, and tree spacing. Allometric equations of tree characteristics extrapolated from ground measurements were used to infer below-canopy morphometric variables. Results are presented from six riparian-forested zones on the Garonne and Allier rivers in southern and central France. The tree detection and crown segmentation (TDCS) method identified individual trees with 85% accuracy, and the TreeVaW method detected trees with 83% accuracy. Tree heights were overall estimated at both river locations with an RMSE error of around 19% for both methods, but crown diameter at the six sites produced large deviations from ground-measured values of above 40% for both methods. Total height-derived trunk diameters using the TDCS method produced the closest roughness coefficient values to the ground-derived roughness coefficients. The stem roughness values produced from this method fell within guideline values

Comparing cost-effectiveness of surface water flood management interventions in a UK catchment

This is the final published version. Available from Wiley via the DOI in this record.Despite significant consequences caused by recent events, surface water flooding has historically been of lower priority relative to fluvial and coastal risks in UK flood management. Legislation and research proposes a variety of innovative interventions to address this; however, widespread application of these remains a challenge due to a number of institutional, economic, and technical barriers. This research applies a framework capable of fast and high-resolution assessment of intervention cost-effectiveness as an opportunity to improve available evidence and encourage uptake of interventions through analysing permutations of type, scale, and distribution in urban catchments. Fast assessment of many scenarios is achieved using a cellular automata flood model and a simplified representation of interventions. Conventional and green strategies are examined across a range of design standard and high-magnitude rainfall events in an urban catchment. Results indicate high-volume rainwater capture interventions demonstrate a significant reduction in estimated annual damage costs, and localised surface water drainage interventions exhibit high cost-effectiveness for damage reduction. Analysis of performance across a wide range of return periods enhances available evidence for option comparison decision support and provides a basis for future resilience assessment of interventions.Engineering and Physical Sciences Research Council (EPSRC

Effects of wave rollers and bottom stress on wave setup

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): C02003, doi:10.1029/2006JC003549.Setup, the increase in the mean water level associated with breaking waves, observed between the shoreline and about 6-m water depth on an ocean beach is predicted well by a model that includes the effects of wave rollers and the bottom stress owing to the mean flow. Over the 90-day observational period, the measured and modeled setup are correlated (squared correlation above 0.59), and agree within about 30%. Although rollers may affect setup significantly on beaches with large amplitude (several meters high) sandbars and may be important in predicting the details of the cross-shore profile of setup, for the data discussed here, rollers have only a small effect on the amount of setup. Conversely, bottom stress (calculated using eddy viscosity and undertow formulations based on the surface dissipation, and assuming that the eddy viscosity is uniform throughout the water column) significantly affects setup predictions. Neglecting bottom stress results in underprediction of the observed setup in all water depths, with maximum underprediction near the shoreline where the observed setup is largest.Funding was provided by the Office of Naval Research, the National Science Foundation, and the Army Research Office