4,307 research outputs found
Bang the Can Slowly: An Investigation into the 2017 Houston Astros
This manuscript is a statistical investigation into the 2017 Major League
Baseball scandal involving the Houston Astros, the World Series championship
winner that same year. The Astros were alleged to have stolen their opponents'
pitching signs in order to provide their batters with a potentially unfair
advantage. This work finds compelling evidence that the Astros on-field
performance was significantly affected by their sign-stealing ploy and
quantifies the effects. The three main findings in the manuscript are: 1) the
Astros' odds of swinging at a pitch were reduced by approximately 27% (OR:
0.725, 95% CI: (0.618, 0.850)) when the sign was stolen, 2) when an Astros
player swung, the odds of making contact with the ball increased roughly 80%
(OR: 1.805, 95% CI: (1.342, 2.675)) on non-fastball pitches, and 3) when the
Astros made contact with a ball on a pitch in which the sign was known, the
ball's exit velocity (launch speed) increased on average by 2.386 (95% CI:
(0.334, 4.451)) miles per hour
Forgiveness Motives Among Evangelical Christians: Implications for Christian Marriage and Family Therapists
Therapists and researchers interested in forgiveness can learn from those who have experienced interpersonal wounds and have chosen to forgive. We interviewed 20 evangelical Christian forgivers, asking about motives for forgiveness. Transcripts were analyzed using qualitative methods. Five categories of motivation are presented: comfort, duty, relational, humility/empathy, and Christian beliefs. Respondents described multiple motives for forgiveness, often combining a desire for comfort or a sense of duty with their Christian beliefs. Four implications for Christian marriage and family therapists are discussed: Expect diversity, avoid moralistic views of motives, remember religious resources in the forgiveness process, and expect benefits, but not immediately
An Infrared Study of the Circumstellar Material Associated with the Carbon Star R Sculptoris
The asymptotic giant branch (AGB) star R Sculptoris (R Scl) is one of the
most extensively studied stars on the AGB. R Scl is a carbon star with a
massive circumstellar shell () which
is thought to have been produced during a thermal pulse event years
ago. To study the thermal dust emission associated with its circumstellar
material, observations were taken with the Faint Object InfraRed CAMera for the
SOFIA Telescope (FORCAST) at 19.7, 25.2, 31.5, 34.8, and 37.1 m. Maps of
the infrared emission at these wavelengths were used to study the morphology
and temperature structure of the spatially extended dust emission. Using the
radiative transfer code DUSTY and fitting the spatial profile of the emission,
we find that a geometrically thin dust shell cannot reproduce the observed
spatially resolved emission. Instead, a second dust component in addition to
the shell is needed to reproduce the observed emission. This component, which
lies interior to the dust shell, traces the circumstellar envelope of R Scl. It
is best fit by a density profile with where
and dust mass of
. The strong departure from an
law indicates that the mass-loss rate of R Scl has not been constant.
This result is consistent with a slow decline in the post-pulse mass-loss which
has been inferred from observations of the molecular gas.Comment: 10 pages, 10 figures, accepted to Ap
Cylinders with Square Cross Section: Paths to Turbulence with Various Angles of Incidence
The path to turbulence in the wake of cylinders with square crosssection is investigated by means of direct numerical simulation, employing a two-dimensional spectral element method and Floquet linear stability analysis. The critical Reynolds number for the onset of the three-dimensional instability modes A, B, C and QP are reported for cylinder incidence angles between 0° and 45°. The Strouhal—Reynolds number relationship, and lift and drag coefficients are also investigated for these incidence angles. Reynolds numbers (based on the side length of the square) up to Re=300 are considered, and a significant variation in bifurcation scenarios are observed for the various incidence angles. At Reynolds numbers greater than Re ≈ 225 for an incidence angle of 45°, a previously unreported asymmetry is detected in the von Kármán vortex street. The cause of this asymmetry is investigated as it presents a possible alternative path to turbulence to that reported in the wakes of other bluff bodies
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Effective Interactive Proofs for Higher-Order Imperative Programs
We present a new approach for constructing and verifying higher-order, imperative programs using the Coq proof assistant. We build on the past work on the Ynot system, which is based on Hoare Type Theory. That original system was a proof of concept, where every program verification was accomplished via laborious manual proofs, with much code devoted to uninteresting low-level details. In this paper, we present a re-implementation of Ynot which makes it possible to implement fully-verified, higher-order imperative programs with reasonable proof burden. At the same time, our new system is implemented entirely in Coq source files, showcasing the versatility of that proof assistant as a platform for research on language design and verification. Both versions of the system have been evaluated with case studies in the verification of imperative data structures, such as hash tables with higher-order iterators. The verification burden in our new system is reduced by at least an order of magnitude compared to the old system, by replacing manual proof with automation. The core of the automation is a simplification procedure for implications in higher-order separation logic, with hooks that allow programmers to add domain-specific simplification rules.
We argue for the effectiveness of our infrastructure by verifying a number of data structures and a packrat parser, and we compare to similar efforts within other projects. Compared to competing approaches to data structure verification, our system includes much less code that must be trusted; namely, about a hundred lines of Coq code defining a program logic. All of our theorems and decision procedures have or build machine-checkable correctness proofs from first principles, removing opportunities for tool bugs to create faulty verifications.Engineering and Applied Science
Illinois River Levees: Sizing Up Their Impact on Flooding and Risk
The Illinois River is separated from its floodplain by a series of levees constructed and modified over time. These levees are subject to overtopping, but the frequency of the critical flood event varies from levee system to system and is not generally known. Investigations to consider reconnecting the river and its floodplain, building resilient river communities, and potentially diverting floods to agricultural land all require information about the land area, land use, structures, and population of each levee protected area. The objective of this research is to provide a comprehensive description of the leveed area along the Illinois River.
Using the United States Army Corps of Engineers (USACE) National Levee Database (NLD), levee systems along the Illinois River were identified based on the availability of highly detailed topographic data. Each levee system was then analyzed in conjunction with the Upper Mississippi River System Flow Frequency Study (UMRSFFS) to determine the critical flood event expected to overtop each levee system.
Based on this overtopping analysis, the areas of inundation landward of each levee system were studied using flooding depth and demographic and economic analysis to produce a representative summary of the risk for each levee system. Flooding depth grids were produced for each levee system representing the extent and depth of inundation expected when a levee system first overtops. Economic analysis included both investigation of average agricultural production per levee system using United States Department of Agriculture soil and crop data, and structural risk exposure using the Federal Emergency Management Agency Hazus-MH risk analysis software.
The 35 levee systems studied have an annual chance of overtopping ranging from 6.9% to less than 0.2% (or 14 to >500 years on average). The average depth of flooding for a levee system due to overtopping ranges from 5.3 feet to 24.1 feet. Across all levee systems analyzed (206,000 acres), the average depth of flooding due to overtopping was 15.4 feet. This suggests that more than 3.1 million acre-feet of floodplain storage is currently disconnected from the Illinois River by the studied levees.
The average gross economic value of crops grown within the levee systems included in this analysis was approximately 130 million dollars per year (based on crop years 2010–2012). Nearly 80% of the land area within the levee systems is devoted to the production of corn and soybeans. The remainder of the land area is evenly divided (about 5% each) among developed lands, open water, and pasture/hay.
The population living within the Illinois River levee systems decreased approximately 1% between 2000 and 2010 to just over 9,500. More than 90% of the studied population lives within just 3 of the 35 studied
levee systems. Although diversity increased slightly between 2000 and 2010, the population remains predominately white. Nearly 60% of the population is aged 18-64 with 26% less than 18 and 14% greater
than 64.
Hazards analysis using the Federal Emergency Management Agency Hazus-MH utility and overtopping projections produces an estimate of total exposure to the General Building Stock (GBS). These exposure
estimates range, in terms of full building replacement value, from insignificant for small agricultural levees to more than 660 million dollars in developed urban areas. Expected damages due to overtopping range from insignificant to more than 155 million dollars. The total exposure to the GBS across all studied levee systems was more than $1.1 billion. Damages to the GBS due to overtopping of all levee systems is expected to be more than 265 million dollars.National Great Rivers Research and Education Centerpublished or submitted for publicationis peer reviewedOpe
Aspects of Common Eider Nesting Ecology in Labrador
The status, distribution, and nesting ecology of common eiders (Somateria mollissima) breeding in Labrador are not well known. This study is an initial effort to improve understanding of the nesting ecology of eiders on the Labrador coast, a zone of intergradation between the northern (S. m. borealis) and American (S. m. dresseri) subspecies of common eider. During 1998 and 1999, 187 islands were surveyed for nesting eiders at four sites (from north to south: Nain, Hopedale, Makkovik, St. Peter’s Bay) along 750 km of the coast. Nest initiation dates (calculated by candling eggs) ranged over a four- to five-week period and were positively associated with latitude: the earliest mean initiation date (5 June) was in St. Peter’s Bay in the south and the latest (27 June) at Nain in the north. Mean clutch size ranged from 3.5 to 4.2 and varied by area and year; eiders nesting in Nain had the smallest clutches. In 1999, the highest nest density (49.8 nests/ha) was observed in Nain and the lowest (3.9 nests/ha) in Makkovik. In some cases, we used boat surveys to assess eider presence and absence and found it to be a reliable method; this search technique could be beneficial to researchers working in remote locations where operational costs are high.On connaît mal le statut, la distribution et l’écologie de nidification de l’eider à duvet (Somateria mollissima) qui se reproduit au Labrador. Cette étude représente un premier pas vers une meilleure compréhension de l’écologie de nidification de l’eider sur la côte du Labrador, une zone de chevauchement entre la sous-espèce du nord (S. m. borealis) et celle américaine (S. m. dresseri) de l’eider à duvet. Durant 1998 et 1999, on a cherché des eiders nicheurs dans 187 îlots à quatre endroits (du nord au sud: Nain, Hopedale, Makkovik, baie de St. Peter’s) répartis sur 750 km de rivage. Les dates du début de la couvaison (calculées en mirant les oeufs) s’étalaient sur une période de quatre à cinq semaines et étaient associées positivement à la latitude: c’est dans la baie de St. Peter’s dans le sud qu’on a observé la date moyenne du début de la couvaison la plus précoce (5 juin), et à Nain dans le nord, la plus tardive (27 juin). La taille moyenne de la couvée allait de 3,5 à 4,2 et variait selon l’endroit et l’année; les eiders qui nichaient à Nain avaient les plus petites couvées. En 1999, la plus forte densité de nids (49,8 nids/ha) a été observée à Nain et la plus faible (3,9 nids/ha), à Makkovik. Dans certains cas, on a utilisé des relevés effectués à partir d’embarcations pour établir la présence et l’absence d’eiders, méthode qui s’est avérée fiable; cette technique de recherche pourrait être bénéfique aux chercheurs travaillant dans des lieux éloignés où les coûts d’opération sont élevés
Variable Hard X-ray Emission from the Candidate Accreting Black Hole in Dwarf Galaxy Henize 2-10
We present an analysis of the X-ray spectrum and long-term variability of the
nearby dwarf starburst galaxy Henize 2-10. Recent observations suggest that
this galaxy hosts an actively accreting black hole with mass ~10^6 M_sun. The
presence of an AGN in a low-mass starburst galaxy marks a new environment for
active galactic nuclei (AGNs), with implications for the processes by which
"seed" black holes may form in the early Universe. In this paper, we analyze
four epochs of X-ray observations of Henize 2-10, to characterize the long-term
behavior of its hard nuclear emission. We analyze observations with Chandra
from 2001 and XMM-Newton from 2004 and 2011, as well as an earlier, less
sensitive observation with ASCA from 1997. Based on detailed analysis of the
source and background, we find that the hard (2-10 keV) flux of the putative
AGN has decreased by approximately an order of magnitude between the 2001
Chandra observation and exposures with XMM-Newton in 2004 and 2011. The
observed variability confirms that the emission is due to a single source. It
is unlikely that the variable flux is due to a supernova or ultraluminous X-ray
source, based on the observed long-term behavior of the X-ray and radio
emission, while the observed X-ray variability is consistent with the behavior
of well-studied AGNs.Comment: 7 pages, 4 figures, 2 tables; accepted for publication in Ap
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Real-world heart rate norms in the Health eHeart study.
Emerging technology allows patients to measure and record their heart rate (HR) remotely by photoplethysmography (PPG) using smart devices like smartphones. However, the validity and expected distribution of such measurements are unclear, making it difficult for physicians to help patients interpret real-world, remote and on-demand HR measurements. Our goal was to validate HR-PPG, measured using a smartphone app, against HR-electrocardiogram (ECG) measurements and describe out-of-clinic, real-world, HR-PPG values according to age, demographics, body mass index, physical activity level, and disease. To validate the measurements, we obtained simultaneous HR-PPG and HR-ECG in 50 consecutive patients at our cardiology clinic. We then used data from participants enrolled in the Health eHeart cohort between 1 April 2014 and 30 April 2018 to derive real-world norms of HR-PPG according to demographics and medical conditions. HR-PPG and HR-ECG were highly correlated (Intraclass correlation = 0.90). A total of 66,788 Health eHeart Study participants contributed 3,144,332 HR-PPG measurements. The mean real-world HR was 79.1 bpm ± 14.5. The 95th percentile of real-world HR was ≤110 in individuals aged 18-45, ≤100 in those aged 45-60 and ≤95 bpm in individuals older than 60 years old. In multivariable linear regression, the number of medical conditions, female gender, increasing body mass index, and being Hispanic was associated with an increased HR, whereas increasing age was associated with a reduced HR. Our study provides the largest real-world norms for remotely obtained, real-world HR according to various strata and they may help physicians interpret and engage with patients presenting such data
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