1,184 research outputs found

### The Nature and Nurture of Sports Performance, Blog 6

Student blog posts from the Great VCU Bike Race Book

### A New Spin on Baseball

All baseball fans know what a curveball is physically, but what is curveball mathematically, and how does it differ from a fastball? The secret of a pitch lies in its spin. In this paper we shall define the spin of a baseball and investigate the effects of its magnitude and direction by employing data collected by MLB.com Gameday from the league\u27s best pitchers. We shall then employ this model to differentiate between the spin of a curveball and that of a fastball. Acknowledgements: We would like to thank our teacher Scott Mitter for all that he has done for us. From making waffles to teaching triple integrals, his input and encouragement have been invaluable. We would also like to thank the University of Dayton faculty for allowing us to participate in the UD Mathematics Day and to continue this paper

### A New Spin on Baseball

All baseball fans know what a curveball is physically, but what is curveball mathematically, and how does it differ from a fastball? The secret of a pitch lies in its spin. In this paper we shall define the spin of a baseball and investigate the effects of its magnitude and direction by employing data collected by MLB.com Gameday from the league\u27s best pitchers. We shall then employ this model to differentiate between the spin of a curveball and that of a fastball. Acknowledgements: We would like to thank our teacher Scott Mitter for all that he has done for us. From making waffles to teaching triple integrals, his input and encouragement have been invaluable. We would also like to thank the University of Dayton faculty for allowing us to participate in the UD Mathematics Day and to continue this paper

### A record of igneous evolution in Elysium, a major martian volcanic province

Â© 2017 The Author(s). A major knowledge gap exists on how eruptive compositions of a single martian volcanic province change over time. Here we seek to fill that gap by assessing the compositional evolution of Elysium, a major martian volcanic province. A unique geochemical signature overlaps with the southeastern flows of this volcano, which provides the context for this study of variability of martian magmatism. The southeastern lava fields of Elysium Planitia show distinct chemistry in the shallow subsurface (down to several decimeters) relative to the rest of the martian mid-to-low latitudes (average crust) and flows in northwest Elysium. By impact crater counting chronology we estimated the age of the southeastern province to be 0.85 Â± 0.08 Ga younger than the northwestern fields. This study of the geochemical and temporal differences between the NW and SE Elysium lava fields is the first to demonstrate compositional variation within a single volcanic province on Mars. We interpret the geochemical and temporal differences between the SE and NW lava fields to be consistent with primary magmatic processes, such as mantle heterogeneity or change in depth of melt formation within the martian mantle due to crustal loading

### The epigenetic clock is correlated with physical and cognitive fitness in the Lothian Birth Cohort 1936

Background: The DNA methylation-based 'epigenetic clock' correlates strongly with chronological age, but it is currently unclear what drives individual differences. We examine cross-sectional and longitudinal associations between the epigenetic clock and four mortality-linked markers of physical and mental fitness: lung function, walking speed, grip strength and cognitive ability. Methods: DNA methylation-based age acceleration (residuals of the epigenetic clock estimate regressed on chronological age) were estimated in the Lothian Birth Cohort 1936 at ages 70 (n=920), 73 (n=299) and 76 (n=273) years. General cognitive ability, walking speed, lung function and grip strength were measured concurrently. Cross-sectional correlations between age acceleration and the fitness variables were calculated. Longitudinal change in the epigenetic clock estimates and the fitness variables were assessed via linear mixed models and latent growth curves. Epigenetic age acceleration at age 70 was used as a predictor of longitudinal change in fitness. Epigenome-wide association studies (EWASs) were conducted on the four fitness measures. Results: Cross-sectional correlations were significant between greater age acceleration and poorer performance on the lung function, cognition and grip strength measures (r range: -0.07 to -0.05, P range: 9.7 x 10 to 0.024). All of the fitness variables declined over time but age acceleration did not correlate with subsequent change over 6 years. There were no EWAS hits for the fitness traits. Conclusions: Markers of physical and mental fitness are associated with the epigenetic clock (lower abilities associated with age acceleration). However, age acceleration does not associate with decline in these measures, at least over a relatively short follow-up

### A universal ultraviolet-optical colour-colour-magnitude relation of galaxies

Although the optical colour-magnitude diagram of galaxies allows one to select red sequence objects, neither can it be used for galaxy classification without additional observational data such as spectra or high-resolution images, nor to identify blue galaxies at unknown redshifts. We show that adding the near ultraviolet colour to the optical CMD reveals a tight relation in the three-dimensional colour-colour-magnitude space smoothly continuing from the "blue cloud" to the "red sequence". We found that 98 per cent of 225,000 low-redshift (Z<0.27) galaxies follow a smooth surface g-r=F(M,NUV-r) with a standard deviation of 0.03-0.07 mag making it the tightest known galaxy photometric relation. There is a strong correlation between morphological types and integrated NUV-r colours. Rare galaxy classes such as E+A or tidally stripped systems become outliers that occupy distinct regions in the 3D parameter space. Using stellar population models for galaxies with different SFHs, we show that (a) the (NUV-r, g-r) distribution is formed by objects having constant and exponentially declining SFR with different characteristic timescales; (b) colour evolution for exponentially declining models goes along the relation suggesting its weak evolution up-to a redshift of 0.9; (c) galaxies with truncated SFHs have very short transition phase offset from the relation thus explaining the rareness of E+A galaxies. This relation can be used as a powerful galaxy classification tool when morphology remains unresolved. Its mathematical consequence is the photometric redshift estimates from 3 broad-band photometric points. This approach works better than most existing photometric redshift techniques applied to multi-colour datasets. Therefore, the relation can be used as an efficient selection technique for galaxies at intermediate redshifts (0.3<Z<0.8) using optical imaging surveys.Comment: 15 pages, 10 figures, accepted to MNRAS. This is an updated version that addresses referee's remarks. All relations have been recomputed using Petrosian magnitudes. The best-fitting relations in the electronic form are available at the project web-page: http://specphot.sai.msu.ru/galaxies

### Involving patients, families and medical staff in the evaluation of 3D printing models of congenital heart disease

Objective: To evaluate the usefulness of 3D printing patient-specific models of congenital heart disease (CHD) from the perspective of different stakeholders potentially benefiting from the technology (patients, parents, clinicians and nurses). &#x0D; Methods: Workshops, focus groups and teaching sessions were organized, each targeting a different group of stakeholders. Sessions involved displaying and discussing different 3D models of CHD. Model evaluation involved questionnaires, audio-recorded discussions and written feedback. &#x0D; Results: All stakeholders expressed a liking for the 3D models and for the patient-specific quality of such models. Patients indicated that 3D models can help them imagine âwhatâs going on insideâ and parents agreed that these tools can spark curiosity in the young people. Clinicians indicated that teaching might be the most relevant application of such novel technology and nurses agreed that 3D models improved their learning experience during a course focused on CHD. &#x0D; Conclusion: The successful engagement of different stakeholders to evaluate 3D printing technology for CHD identified different priorities, highlighting the importance of eliciting the views of different groups. &#x0D; Practice Implications: A PPI-based approach in the evaluation and translation of 3D printing technology may increase patient empowerment, improve patient-doctor communication and provide better access to a new teaching and training tool.</jats:p

### Narrowing the Boundaries of the Genetic Architecture of Schizophrenia

Genetic architecture of a disease comprises the number, frequency, and effect sizes of genetic risk alleles and the way in which they combine together. Before the genomic revolution, the only clue to underlying genetic architecture of schizophrenia came from the recurrence risks to relatives and the segregation patterns within families. From these clues, very simple genetic architectures could be rejected, but many architectures were consistent with the observed family data. The new era of genome-wide association studies can provide further clues to the genetic architecture of schizophrenia. We explore models of genetic architecture by description rather than the mathematics that underpins them. We conclude that the new genome-wide data allow us to narrow the boundaries on the models of genetic architecture that are consistent with the observed data. A genetic architecture of many common variants of moderate (relative risk > approximately 1.2) can be excluded, yet there is evidence that current generation genome-wide chips do tag an important proportion of the genetic variation for schizophrenia and that the underlying causal variants will include common variants of small effect as well as rarer variants of larger effect. Together, these observations imply that the total number of genetic variants is very largeâof the order of thousands. The first generation of studies have generated hypotheses that should be testable in the near future and will further narrow the boundaries on genetic architectures that are consistent with empirical data

### Basalt-trachybasalt samples in Gale Crater, Mars

The ChemCam instrument on the Mars Science Laboratory (MSL) rover, Curiosity, observed numerous igneous float rocks and conglomerate clasts, reported previously. A new statistical analysis of single-laser-shot spectra of igneous targets observed by ChemCam shows a strong peak at ~55 wt% SiO2 and 6 wt% total alkalis, with a minor secondary maximum at 47â51 wt% SiO2 and lower alkali content. The centers of these distributions, together with the rock textures, indicate that many of the ChemCam igneous targets are trachybasalts, Mg#=27 but with a secondary concentration of basaltic material,with a focus of compositions around Mg#=54. We suggest that all of these igneous rocks resulted from low-pressure, olivine-dominated fractionation of Adirondack (MER) class-type basalt compositions. This magmatism has subalkaline, tholeiitic affinities. The similarity of the basalt endmember to much of the Gale sediment compositions in the first 1000 sols of the MSL mission suggests that this type of Fe-rich, relatively low-Mg#, olivine tholeiite is the dominant constituent of the Gale catchment that is the source material for the fine-grained sediments in Gale. The similarity to many Gusev igneous compositions suggests that it is a major constituent of ancient Martian magmas, and distinct from the shergottite parental melts thought to be associated with Tharsis and the Northern Lowlands. The Gale Crater catchment sampled a mixture of this tholeiitic basalt along with alkaline igneous material, together giving some analogies to terrestrial intraplate magmatic provinces
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