767 research outputs found
Riparian plant water relations along the north fork of the Kings River, California
Plant water relations of five obligate ripar-ian species were studied along California\u27s North Fork Kings River. Diurnal stomatal conductance, transpi-ration, and xylem pressure potentials were measured throughout the 1986 growing season and in mid-season in 1987. Patterns were similar for all species although absolute values varied considerably. Maximum stomatal conductance occurred early in the day and season during favorable environmental conditions and decreased as air temperature and the vapor pressure difference between the leaf and air increased. Maximum transpiration rates occurred in mid-morning and mid-summer resulting in estimated daily water losses per unit sunlit leaf area of 163-328 mol H2O m-2. Predawn xylem pressure poten-tials remained high in 1986 when streamflows averaged 1.41 m3/s (50 cfs), however they were notably lower in 1987 at 0.7 m3/s (25 cfs)
Impact of Home Field Advantage: Analyzed Across Three Professional Sports
We examined the impact of home-field advantage in the NFL, NBA, and MLB. We defined home-field advantage as winning more than 50% of the home games. Additionally, we took into consideration how season length could act as a moderator and influence the impact of home-field advantage. We collected data from the 2015 NBA and MLB seasons and the 2015 and 2016 NFL seasons to determine statistical significance. In total, we got data from 4,141 games to analyze. We found that there is statistical significance that the home team has a better chance of winning than the away team across the NFL, NBA, and MLB. We also found that season length has a significant impact on home team winning percentage
Acknowledgement Response and Interference Timing During the Processing of Voice and Datalink ATC Commands
In aviation, effective communication between air traffic control (ATC) and pilots is critical to pilot performance and safety. Problems and limitations of current radio communications initiated the development of datalink technology. Datalink is a text system used to send messages between ATC and pilots. Although datalink was intended to reduce errors associated with radio communication, there are new concerns related to changes in information processing demands associated with executing speech and text ATC commands. In addition, the nature of responses differs between voice and datalink systems. In a voice environment, responses are immediate. However, time delays exist with datalink. These time delays may create an opportunity for interference. Therefore, the timing of interference and the acknowledgement response on command execution performance were examined during the processing of simulated ATC commands. Verbal and central executive (CE) interference tasks were presented before or after the acknowledgement. Participants received both speech and text commands, responded by a verbal or manual acknowledgement, and set the controls in a flight simulator. Results demonstrated no differences between speech and text formats with a verbal acknowledgement. However, there was an advantage for a manual acknowledgement with longer messages. Regarding interference timing, CE as opposed to verbal interference prior to an acknowledgement had a greater negative effect on control setting performance and the magnitude of this effect was larger in the text condition. Thus, text information appears to be more susceptible to the negative effects of interference as resources begin to reach capacity. However, the differences between the sources of interference decreased with an increase in message length. Therefore, the timing and type of interference can have differential effects on resource capacity and the ability to rehearse information in memory. It was also suggested that the processing code of a task is of more importance than the response code. The findings are interpreted within the context of a working memory and resource perspective and implications are discussed with regard to the communication process in aviation
Effectiveness of a Faith-placed Cardiovascular Health Promotion Intervention for Rural Adults
Introduction: Cardiovascular disease (CVD) is the leading cause of mortality in the US. Further, rural US adults experience disproportionately high CVD prevalence and mortality compared to non-rural. Cardiovascular risk-reduction interventions for rural adults have shown short-term effectiveness, but long-term maintenance of outcomes remains a challenge. Faith organizations offer promise as collaborative partners for translating evidence-based interventions to reduce CVD.
Methods: We adapted and implemented a collaborative, faith-placed, CVD risk-reduction intervention in rural Illinois. We used a quasi-experimental, pre-post design to compare changes in dietary and physical activity among participants. Intervention components included Heart Smart for Women (HSFW), an evidence-based program implemented weekly for 12 weeks followed by Heart Smart Maintenance (HSM), implemented monthly for two years. Participants engaged in HSFW only, HSM only, or both. We used regression and generalized estimating equations models to examine changes in outcomes after one year.
Results: Among participants who completed both baseline and one-year surveys (n = 131), HSFW+HSM participants had significantly higher vegetable consumption (p = .007) and combined fruit/vegetable consumption (p = .01) compared to the HSM-only group at one year. We found no differences in physical activity.
Conclusion: Improving and maintaining CVD-risk behaviors is a persistent challenge in rural populations. Advancing research to improve our understanding of effective translation of CVD risk-reduction interventions in rural populations is critical
Interpreting forest and grassland biome productivity utilizing nested scales of image resolution and biogeographical analysis
Several hardware, software, and data collection problems encountered were conquered. The Geographic Information System (GIS) data from other systems were converted to ERDAS format for incorporation with the image data. Statistical analysis of the relationship between spectral values and productivity is being pursued. Several project sites, including Jackson, Pope, Boulder, Smokies, and Huntington Forest are evolving as the most intensively studied areas, primarily due to availability of data and time. Progress with data acquisition and quality checking, more details on experimental sites, and brief summarizations of research results and future plans are discussed. Material on personnel, collaborators, facilities, site background, and meetings and publications of the investigators are included
Heterocyst placement strategies to maximize growth of cyanobacterial filaments
Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria
develop a regular pattern of heterocyst cells that fix nitrogen for the
remaining vegetative cells. We examine three different heterocyst placement
strategies by quantitatively modelling filament growth while varying both
external fixed-nitrogen and leakage from the filament. We find that there is an
optimum heterocyst frequency which maximizes the growth rate of the filament;
the optimum frequency decreases as the external fixed-nitrogen concentration
increases but increases as the leakage increases. In the presence of leakage,
filaments implementing a local heterocyst placement strategy grow significantly
faster than filaments implementing random heterocyst placement strategies. With
no extracellular fixed-nitrogen, consistent with recent experimental studies of
Anabaena sp. PCC 7120, the modelled heterocyst spacing distribution using our
local heterocyst placement strategy is qualitatively similar to experimentally
observed patterns. As external fixed-nitrogen is increased, the spacing
distribution for our local placement strategy retains the same shape while the
average spacing between heterocysts continuously increases.Comment: This is an author-created, un-copyedited version of an article
accepted for publication in Physical Biology. IOP Publishing Ltd is not
responsible for any errors or omissions in this version of the manuscript or
any version derived from it. The definitive publisher-authenticated version
will be available onlin
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