scholarly journals A simple relationship for predicting marathon performance from training: Is it generally applicable?

2020 ◽  
Vol 17 (2) ◽  
Author(s):  
Giovanni Tanda
Keyword(s):  
Simple Relationship ◽  
Marathon Performance

Simple Relationship Quality Measures

2020 ◽  
Author(s):  
Sylvia Niehuis
Keyword(s):  
Convergent Validity ◽  
Online Survey ◽  
Romantic Partners ◽  
Age Dating ◽  
Simple Relationship ◽  
Cross Sectional ◽  
Single Item ◽  
College Age ◽  
Close Relationship ◽  
Dating Couples

Issues in applied survey research, including minimizing respondent burden to encourage survey completion and the increasing administration of questionnaires over smartphones, have intensified efforts to create short measures. We conducted two studies to examine the psychometric properties of single-item measures of four close-relationship variables: satisfaction, love, conflict, and commitment. Study 1 was longitudinal, surveying an initial sample of 121 college-age dating couples at three monthly phases. Romantic partners completed single- and multi-item measures of the four constructs, along with other variables, to examine test-retest reliability and convergent (single-item measures with their corresponding multi-item scales), concurrent, and predictive validity. Our single-item measures of satisfaction, love, and commitment exhibited impressive psychometric qualities, but our single-item conflict measure performed somewhat less strongly. Study 2, a cross-sectional online survey (n = 280; mainly through Facebook), showed strong convergent validity of the single-item measures, including a .60 correlation between single- and multi-item conflict measures.

scholarly journals Low ventilatory responsiveness to transient hypoxia or breath-holding predicts fast marathon performance in healthy middle-aged and older men

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bartłomiej Paleczny ◽  
Rafał Seredyński ◽  
Małgorzata Wyciszkiewicz ◽  
Adrianna Nowicka-Czudak ◽  
Wojciech Łopusiewicz ◽  
...  
Keyword(s):  
Plasma Renin ◽  
Older Men ◽  
Individual Performance ◽  
Breath Holding ◽  
Vasomotor Tone ◽  
Younger Men ◽  
The Individual ◽  
Peripheral Chemoreflex ◽  
Sympathetic Vasomotor Tone ◽  
Marathon Performance

AbstractThe aim of this study was to test the utility of haemodynamic and autonomic variables (e.g. peripheral chemoreflex sensitivity [PCheS], blood pressure variability [BPV]) for the prediction of individual performance (marathon time and VO2max) in older men. The post-competition vasodilation and sympathetic vasomotor tone predict the marathon performance in younger men, but their prognostic relevance in older men remains unknown. The peripheral chemoreflex restrains exercise-induced vasodilation via sympathetically-mediated mechanism, what makes it a plausible candidate for the individual performance marker. 23 men aged ≥ 50 year competing in the Wroclaw Marathon underwent an evaluation of: resting haemodynamic parameters, PCheS with two methods: transient hypoxia and breath-holding test (BHT), cardiac barosensitivity, heart rate variability (HRV) and BPV, plasma renin and aldosterone, VO2max in a cardiopulmonary exercise test (CPET). All tests were conducted twice: before and after the race, except for transient hypoxia and CPET which were performed once, before the race. Fast marathon performance and high VO2max were correlated with: low ventilatory responsiveness to hypoxia (r =  − 0.53, r = 0.67, respectively) and pre-race BHT (r =  − 0.47, r = 0.51, respectively), (1) greater SD of beat-to-beat SBP (all p < 0.05). Fast performance was related with an enhanced pre-race vascular response to BHT (r =  − 0.59, p = 0.005). The variables found by other studies to predict the marathon performance in younger men: post-competition vasodilation, sympathetic vasomotor tone (LF-BPV) and HRV were not associated with the individual performance in our population. The results suggest that PCheS (ventilatory response) predicts individual performance (marathon time and VO2max) in men aged ≥ 50 yeat. Although cause-effect relationship including the role of peripheral chemoreceptors in restraining the post-competition vasodilation via the sympathetic vasoconstrictor outflow may be hypothesized to underline these findings, the lack of correlation between individual performance and both, the post-competition vasodilation and the sympathetic vasomotor tone argues against such explanation. Vascular responsiveness to breath-holding appears to be of certain value for predicting individual performance in this population, however.

Comparison of PIR to PIPESAFE-Based 1% Lethality Zones for Natural Gas Pipelines

2014 ◽  
Author(s):  
Aleksandar Tomic ◽  
Shahani Kariyawasam
Keyword(s):  
Natural Gas ◽  
Small Diameter ◽  
Gas Pipeline ◽  
Accurate Estimation ◽  
Simple Relationship ◽  
Gas Pipelines ◽  
Friction Forces ◽  
Natural Gas Pipelines ◽  
Decay Factor ◽  
Outflow Rate

A lethality zone due to an ignited natural gas release is often used to characterize the consequences of a pipeline rupture. A 1% lethality zone defines a zone where the lethality to a human is greater than or equal to 1%. The boundary of the zone is defined by the distance (from the point of rupture) at which the probability of lethality is 1%. Currently in the gas pipeline industry, the most detailed and validated method for calculating this zone is embodied in the PIPESAFE software. PIPESAFE is a software tool developed by a joint industry group for undertaking quantitative risk assessments of natural gas pipelines. PIPESAFE consequence models have been verified in laboratory experiments, full scale tests, and actual failures, and have been extensively used over the past 10–15 years for quantitative risk calculations. The primary advantage of using PIPESAFE is it allows for accurate estimation of the likelihood of lethality inside the impacted zone (i.e. receptors such as structures closer to the failure are subject to appropriately higher lethality percentages). Potential Impact Radius (PIR) is defined as the zone in which the extent of property damage and serious or fatal injury would be expected to be significant. It corresponds to the 1% lethality zone for a natural gas pipeline of a certain diameter and pressure when thermal radiation and exposure are taken into account. PIR is one of the two methods used to identify HCAs in US (49 CFR 192.903). Since PIR is a widely used parameter and given that it can be interpreted to delineate a 1% lethality zone, it is important to understand how PIR compares to the more accurate estimation of the lethality zones for different diameters and operating pressures. In previous internal studies, it was found that PIR, when compared to the more detailed measures of the 1% lethality zone, could be highly conservative. This conservatism could be beneficial from a safety perspective, however it is adding additional costs and reducing the efficiency of the integrity management process. Therefore, the goal of this study is to determine when PIR is overly conservative and to determine a way to address this conservatism. In order to assess its accuracy, PIR was compared to a more accurate measure of the 1% lethality zone, calculated by PIPESAFE, for a range of different operating pressures and line diameters. Upon comparison of the distances calculated through the application of PIR and PIPESAFE, it was observed that for large diameters pipelines the distances calculated by PIR are slightly conservative, and that this conservativeness increases exponentially for smaller diameter lines. The explanation for the conservatism of the PIR for small diameter pipelines is the higher wall friction forces per volume transported in smaller diameter lines. When these higher friction forces are not accounted for it leads to overestimation of the effective outflow rate (a product of the initial flow rate and the decay factor) which subsequently leads to the overestimation of the impact radius. Since the effective outflow rate is a function of both line pressure and diameter, a simple relationship is proposed to make the decay factor a function of these two variables to correct the excess conservatism for small diameter pipelines.

Spectral Theory for Skip-Free Markov Chains

1989 ◽  
Vol 3 (1) ◽  
pp. 77-88 ◽  
Author(s):  
Joseph Abate ◽  
Ward Whitt
Keyword(s):  
Markov Chains ◽  
Spectral Theory ◽  
First Passage Time ◽  
Passage Time ◽  
First Passage Times ◽  
Simple Relationship ◽  
First Passage ◽  
Birth And Death Processes ◽  
The Laplace Transform ◽  
Passage Times

The distribution of upward first passage times in skip-free Markov chains can be expressed solely in terms of the eigenvalues in the spectral representation, without performing a separate calculation to determine the eigenvectors. We provide insight into this result and skip-free Markov chains more generally by showing that part of the spectral theory developed for birth-and-death processes extends to skip-free chains. We show that the eigenvalues and eigenvectors of skip-free chains can be characterized in terms of recursively defined polynomials. Moreover, the Laplace transform of the upward first passage time from 0 to n is the reciprocal of the nth polynomial. This simple relationship holds because the Laplace transforms of the first passage times satisfy the same recursion as the polynomials except for a normalization.

Chemical distinction between igneous and metamorphic orthopyroxenes especially those coexisting with Ca-rich clinopyroxenes: a re-evaluation

1983 ◽  
Vol 47 (343) ◽  
pp. 143-151 ◽  
Author(s):  
Frans J. M. Rietmeijer
Keyword(s):  
Simple Relationship ◽  
Physical Conditions

AbstractA previously suggested simple relationship in a diagram of(Al2O3vs. MgO + FeO + Fe2O3)opx for the distinction between igneous and metamorphic orthopyroxenes is shown to be inadequate. A revised diagram is presented and its limitations are discussed. A diagram showing Fe2+/(Fe2+ + Mg) vs. 100Ca/(Fe2+ + Mg + Ca) for orthopyroxenes coexisting with Ca-rich clinopyroxenes proves to be useful for the discrimination of igneous and metamorphic orthopyroxenes and for evaluation of the extent and physical conditions of regional orthopyroxene re-equilibration.

scholarly journals Molecular homology and multiple-sequence alignment: an analysis of concepts and practice

2015 ◽  
Vol 28 (1) ◽  
pp. 46 ◽  
Author(s):  
David A. Morrison ◽  
Matthew J. Morgan ◽  
Scot A. Kelchner
Keyword(s):  
Sequence Alignment ◽  
Multiple Sequence Alignment ◽  
Molecular Data ◽  
Simple Relationship ◽  
Sequence Alignments ◽  
Multiple Sequence ◽  
Molecular Change ◽  
Nucleotide Homology ◽  
Tree Building ◽  
Molecular Homology

Sequence alignment is just as much a part of phylogenetics as is tree building, although it is often viewed solely as a necessary tool to construct trees. However, alignment for the purpose of phylogenetic inference is primarily about homology, as it is the procedure that expresses homology relationships among the characters, rather than the historical relationships of the taxa. Molecular homology is rather vaguely defined and understood, despite its importance in the molecular age. Indeed, homology has rarely been evaluated with respect to nucleotide sequence alignments, in spite of the fact that nucleotides are the only data that directly represent genotype. All other molecular data represent phenotype, just as do morphology and anatomy. Thus, efforts to improve sequence alignment for phylogenetic purposes should involve a more refined use of the homology concept at a molecular level. To this end, we present examples of molecular-data levels at which homology might be considered, and arrange them in a hierarchy. The concept that we propose has many levels, which link directly to the developmental and morphological components of homology. Of note, there is no simple relationship between gene homology and nucleotide homology. We also propose terminology with which to better describe and discuss molecular homology at these levels. Our over-arching conceptual framework is then used to shed light on the multitude of automated procedures that have been created for multiple-sequence alignment. Sequence alignment needs to be based on aligning homologous nucleotides, without necessary reference to homology at any other level of the hierarchy. In particular, inference of nucleotide homology involves deriving a plausible scenario for molecular change among the set of sequences. Our clarifications should allow the development of a procedure that specifically addresses homology, which is required when performing alignment for phylogenetic purposes, but which does not yet exist.

Characterization of barley silage – maturity relationships for Central Alberta

1992 ◽  
Vol 72 (4) ◽  
pp. 1009-1020 ◽  
Author(s):  
V. S. Baron ◽  
A. C. Dick ◽  
M. S. Wolynetz
Keyword(s):  
Harvest Index ◽  
Climatic Conditions ◽  
Forage Yield ◽  
Simple Relationship ◽  
Grain Production ◽  
Hordeum Vulgare L ◽  
Standard Type ◽  
Plant Yield ◽  
Whole Plant

Production of high-quality whole-plant barley (Hordeum vulgare L.) silage requires an understanding of the relationships among whole-plant percent dry matter (WPDM), whole-plant yield parameters reflecting both whole plant and kernel maturity, grain-to-straw ratio (harvest index) and in vitro digestible organic matter (IVDOM) over the grain-filling period. Eight six-row, standard-type barley cultivars, representative of the range of maturity and stature of cultivars recommended for grain production in Alberta, were grown at Lacombe, Alberta during 1983 and 1984. Seven weekly whole-plant harvests were carried out on each cultivar beginning at heading. Fresh and dry weights on whole-plant and kernel fractions at each harvest allowed calculation of the essential parameters. Regression analyses were used to determine whether several production-related response variables could be predicted from variables such as WPDM, days after heading and cumulative growing degree days (DD) greater than 5 °C after heading. All cultivars exhibited similar trends with DD after heading for these relationships over two years of very different climatic conditions. IVDOM did not vary (P > 0.05) during the growing seasons indicating that IVDOM content cannot be a criterion for determining harvest date. Other relationships indicated that if whole-plant harvest occurred at 30% WPDM it would precede the time of maximum whole-plant yield and grain maturity by 160 and 208 DD, respectively, resulting in a loss in potential whole-plant yield of about 17%. Cultivars which produce more herbage but are too late maturing for grain production could be used to offset this yield loss and there may be a place in barley breeding programs for late-maturing, tall, strong-strawed cultivars specifically for silage production. For havest index, a large difference (8%) between years indicated that a simple relationship between harvest index and DD was not adequate to routinely predict grain content in barley silage.Key words: Silage, whole-plant maturity, barley, forage, yield

Scaling bat wingbeat frequency and amplitude

2002 ◽  
Vol 205 (17) ◽  
pp. 2615-2626 ◽  
Author(s):  
R. D. Bullen ◽  
N. L. McKenzie
Keyword(s):  
Lower Half ◽  
Flight Speed ◽  
Simple Relationship ◽  
Wingbeat Frequency ◽  
Wing Area ◽  
High Speeds ◽  
Second Mode ◽  
Speed Range

SUMMARYWingbeat frequency (fw) and amplitude(θw) were measured for 23 species of Australian bat,representing two sub-orders and six families. Maximum values were between 4 and 13 Hz for fw, and between 90 and 150° forθ w, depending on the species. Wingbeat frequency for each species was found to vary only slightly with flight speed over the lower half of the speed range. At high speeds, frequency is almost independent of velocity. Wingbeat frequency (Hz) depends on bat mass (m, kg) and flight speed (V, ms-1) according to the equation: fw=5.54-3.068log10m-2.857log10V. This simple relationship applies to both sub-orders and to all six families of bats studied. For 21 of the 23 species, the empirical values were within 1 Hz of the model values. One species, a small molossid, also had a second mode of flight in which fw was up to 3 Hz lower for all flight speeds.The following relationship predicts wingbeat amplitude to within±15° from flight speed and wing area (SREF,m2) at all flight speeds:θ w=56.92+5.18V+16.06log10SREF. This equation is based on data up to and including speeds that require maximum wingbeat amplitude to be sustained. For most species, the maximum wingbeat amplitude was 140°.

Conditions for efficient charge generation preceded by energy transfer process in non-fullerene organic solar cells

2021 ◽  
Author(s):  
L. Benatto ◽  
C. A. M. Moraes ◽  
G. Candiotto ◽  
K. R. A. Sousa ◽  
J. P. A. Souza ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Solar Cells ◽  
Binding Energy ◽  
Transfer Process ◽  
Organic Solar Cells ◽  
Driving Force ◽  
Energy Transfer Process ◽  
Simple Relationship ◽  
Charge Generation ◽  
Efficient Charge

Our results provide a simple relationship involving the driving force and binding energy of CT state to maximize charge generation in non-fullerene organic solar cells.

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