74 research outputs found
Towards a theoretical determination of the geographical probability distribution of meteoroid impacts on Earth
Tunguska and Chelyabinsk impact events occurred inside a geographical area of
only 3.4\% of the Earth's surface. Although two events hardly constitute a
statistically significant demonstration of a geographical pattern of impacts,
their spatial coincidence is at least tantalizing. To understand if this
concurrence reflects an underlying geographical and/or temporal pattern, we
must aim at predicting the spatio-temporal distribution of meteoroid impacts on
Earth. For this purpose we designed, implemented and tested a novel numerical
technique, the "Gravitational Ray Tracing" (GRT) designed to compute the
relative impact probability (RIP) on the surface of any planet. GRT is inspired
by the so-called ray-casting techniques used to render realistic images of
complex 3D scenes. In this paper we describe the method and the results of
testing it at the time of large impact events. Our findings suggest a
non-trivial pattern of impact probabilities at any given time on Earth.
Locations at from the apex are more prone to impacts, especially at
midnight. Counterintuitively, sites close to apex direction have the lowest
RIP, while in the antapex RIP are slightly larger than average. We present here
preliminary maps of RIP at the time of Tunguska and Chelyabinsk events and
found no evidence of a spatial or temporal pattern, suggesting that their
coincidence was fortuitous. We apply the GRT method to compute theoretical RIP
at the location and time of 394 large fireballs. Although the predicted
spatio-temporal impact distribution matches marginally the observed events, we
successfully predict their impact speed distribution.Comment: 16 pages, 11 figures. Accepted for publication in MNRA
Decision-making of English Netball Superleague umpires: Contextual and dispositional influences
Objectives. The decisions made by officials have a direct bearing on the outcomes of competitive sport contests. In an exploratory study, we examine the interrelationships between the decisions made by elite netball umpires, the potential contextual and environmental influences (e.g., crowd size), and the umpires’ dispositional tendencies – specifically, their propensity to deliberate and ruminate on their decisions.
Design/Method. Filmed footage from 60 England Netball Superleague matches was coded using performance analysis software. We measured the number of decisions made overall, and for home and away teams; league position; competition round; match quarter; and crowd size. Additionally, 10 umpires who officiated in the matches completed the Decision-Specific Reinvestment Scale (DSRS).
Results. Regression analyses predicted that as home teams’ league position improved the number of decisions against away teams increased. A model comprising competition round and average league position of both teams predicted the number of decisions made in matches, but neither variable emerged as a significant predictor. The umpire analyses revealed that greater crowd size was associated with an increase in decisions against away teams. The Decision Rumination factor was strongly negatively related to the number of decisions in Quarters 1 and 3, this relationship was driven by fewer decisions against home teams by umpires who exhibited higher Rumination subscale scores.
Conclusions. These findings strengthen our understanding of contextual, environmental, and dispositional influences on umpires’ decision-making behaviour. The tendency to ruminate upon decisions may explain the changes in decision behaviour in relation to the home team advantage effect
Decision-making of English Netball Superleague umpires: contextual and dispositional influences
Objectives: The decisions made by officials have a direct bearing on the outcomes of competitive sport contests. In an exploratory study, we examine the interrelationships between the decisions made by elite netball umpires, the potential contextual and environmental influences (e.g., crowd size), and the umpires' dispositional tendencies – specifically, their propensity to deliberate and ruminate on their decisions.
Design/Method: Filmed footage from 60 England Netball Superleague matches was coded using performance analysis software. We measured the number of decisions made overall, and for home and away teams; league position; competition round; match quarter; and crowd size. Additionally, 10 umpires who officiated in the matches completed the Decision-Specific Reinvestment Scale (DSRS).
Results: Regression analyses predicted that as home teams' league position improved the number of decisions against away teams increased. A model comprising competition round and average league position of both teams predicted the number of decisions made in matches, but neither variable emerged as a significant predictor. The umpire analyses revealed that greater crowd size was associated with an increase in decisions against away teams. The Decision Rumination factor was strongly negatively related to the number of decisions in Quarters 1 and 3, this relationship was driven by fewer decisions against home teams by umpires who exhibited higher Rumination subscale scores.
Conclusions: These findings strengthen our understanding of contextual, environmental, and dispositional influences on umpires' decision-making behaviour. The tendency to ruminate upon decisions may explain the changes in decision behaviour in relation to the home team advantage effect
Day-time effect on postural stability in young sportsmen
stabilometry is commonly used from clinicians and posturologists for stability and postural assessment of patients. In the daily practice a large number of posturologists are usual to control the effect of their treatments on the same subject through stabilometry but tests are not always performed at the same time, so it is necessary to be sure that data are not influenced by the time-of-day. The aim of this study was to evaluate the time-of-day effect on stabilometric parameters and theirs variation
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Assessing racial/ethnic and nativity disparities in US cancer mortality using a new integrated platform
Foreign-born (FB) populations in the US have significantly increased, yet cancer trends remain unexplored. Survey-based Population-Adjusted Rate Calculator (SPARC) is a new tool for evaluating nativity differences in cancer mortality.
Using SPARC, we calculated 3-year (2016-2018) age-adjusted mortality rates (AAMRs) and rate ratios (RRs) for common cancers by sex, age group, race/ethnicity, and nativity. Trends by nativity were examined for the first time for 2006-2018. Traditional cancer statistics draw populations from decennial censuses. However, nativity-stratified populations are from the American Community Surveys, thus involve sampling errors. To rectify this, SPARC employed bias-corrected estimators. Death counts came from the National Vital Statistics System.
AAMRs were higher among US-born (UB) populations across nearly all cancer types, with the largest UB- FB difference observed in lung cancer among Black females (RR = 3.67, 95%CI = 3.37-4.00). The well-documented White-Black differences in breast cancer mortality existed mainly among UB women. For all cancers combined, descending trends were more accelerated for the UB compared to the FB in all race/ethnicity groups with changes ranging from -2.6% per year in UB Black males to stable (non-significant) among FB Black females. Pancreas and liver cancers were exceptions with increasing, stable, or decreasing trends depending on nativity and race/ethnicity. Notably, FB Black males and FB Hispanic males did not show a favorable decline in colorectal cancer mortality.
While all groups show beneficial cancer mortality trends, those with higher rates in 2006 have experienced sharper declines. Persistent disparities between the UB and the FB, especially among Black people, necessitate further investigation
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