Seam Shifted Wake in the Magnus and Non-Magnus Directions

An experiment was done to look at the effect baseball seams can have on how a pitched baseball moves in flight. Both non-spinning and spinning baseballs were analyzed in this study. Data was taken and analyzed at 60, 90, and 110 MPH to determine the influence of velocity and altitude on the ability of seams to alter the trajectory of a pitched baseball. Additionally, a ball\u27s spin causes movement in a certain direction that is dependent on the spin axis. A second focus of this study was on the effect of baseball seams changing the movement in the same direction as the movement caused by a ball\u27s spin. Taking and analyzing data of the air flow around a spinning baseball in flight led to the finding of specific areas of the baseball\u27s surface where a seam can change this movement. These experiments were done using official MLB baseballs moving at 90 MPH and spinning at 1300, 1800, and 2300 RPM

Training certified detectives to track down the intrinsic shortcuts in COVID-19 chest x-ray data sets

Deep learning faces a significant challenge wherein the trained models often underperform when used with external test data sets. This issue has been attributed to spurious correlations between irrelevant features in the input data and corresponding labels. This study uses the classification of COVID-19 from chest x-ray radiographs as an example to demonstrate that the image contrast and sharpness, which are characteristics of a chest radiograph dependent on data acquisition systems and imaging parameters, can be intrinsic shortcuts that impair the model\u27s generalizability. The study proposes training certified shortcut detective models that meet a set of qualification criteria which can then identify these intrinsic shortcuts in a curated data set

Comparison of bare root and RPM seedling production technologies : implications for agroforestry

Paper presented at the 12th North American Agroforesty Conference, which was held June 4-9, 2011 in Athens, Georgia.In Ashton, S. F., S.W. Workman, W.G. Hubbard and D.J. Moorhead, eds. Agroforestry: A Profitable Land Use. Proceedings, 12th North American Agroforestry Conference, Athens, GA, June 4-9, 2011.'Root Production Method' (RPM) technology significantly increases the development of root systems in containerized seedlings. As an alternative to bare root seedlings, RPM seedlings have been promoted as a method to increase growth and survivability of hardwood trees. However, few scientific studies have been conducted that would support these claims. Three oak species (Quercus spp.) were the focus of this study. Seed was collected from a single mother tree of black oak (Quercus velutina, Lam.), white oak (Quercus alba Linn.), and swamp white oak (Quercus bicolor Willd.). Half of the seed from each mother tree was used to produce RPM, the other half bare root stock, (i.e. half siblings) which were planted in the fall (RPM) of 1996 or spring (bare root) of 1997 at the Horticulture and Agroforestry Research Center, New Franklin, MO. After 14 years in the field, bare root and RPM trees were harvested for each species and total above ground weight was recorded. Statistical analysis of the data was conducted using least-square means and a method of orthogonal contrasts to determine if significant differences existed between the biomass of bare root and RPM trees. Results showed that the RPM trees had up to twice as much above-ground biomass weight as the bare root trees of the same age. Implications of this study suggest that RPM trees could be used in agroforestry practices as a way of increasing carbon sequestration and biomass production. In addition, the significant increase in growth that was observed should serve to enhance interest in adopting agroforestry practices.Larry D. Godsey (1), John P. Dwyer (2), W. Dusty Walter (1) and Harold 'Gene' Garrett (1) ; 1. University of Missouri Center for Agroforestry, Columbia, MO. 2. Department of Forestry, School of Natural Resources, University of Missouri-Columbia,Columbia, MO.Includes bibliographical references

Evolutionarily conserved and diverged alternative splicing events show different expression and functional profiles

To better decipher the functional impact of alternative splicing, we classified alternative splicing events in 10 818 pairs of human and mouse genes based on conservation at genome and transcript levels. Expression levels of conserved alternative splices in human and mouse expressed sequence tag databases show strong correlation, indicating that alternative splicing is similarly regulated in both species. A total of 43% (8921) of mouse alternative splices could be found in the human genome but not in human transcripts. Five of eleven tested mouse predictions were observed in human tissues, demonstrating that mouse transcripts provide a valuable resource for identifying alternative splicing events in human genes. Combining gene-specific measures of conserved and diverged alternative splicing with both gene classification based on Gene Ontology (GO) and microarray-determined gene expression in 52 diverse human tissues and cell lines, we found conserved alternative splicing most enriched in brain-expressed signaling pathways. Diverged alternative splicing is more prevalent in testis and cancerous cell line up-regulated processes, including protein biosynthesis, responses to stress and responses to endogenous stimuli. Using conservation as a surrogate for functional significance, these results suggest that alternative splicing plays an important role in enhancing the functional capacity of central nervous systems, while non-functional splicing more frequently occurs in testis and cell lines, possibly as a result of cellular stress and rapid proliferation

Conservation genetics of cyprinid fishes in the upper Nueces River basin in central Texas

Sequences of the mitochondrial (mt) NADH dehydrogenase subunit 5 gene (ND5) were acquired to assess genetic diversity and female effective population size (Nef) of two forms of Cyprinella (C. lepida and C. sp. cf lepida) and two species of Dionda (D. serena and D. texensis) in headwaters of three rivers in the upper Nueces River basin in central Texas. As documented in prior studies, two divergent clades of haplotypes of mtDNA were found in both genera: one in the Frio and Sabinal rivers, representing C. lepida and D. serena; one in the Nueces River, representing C. sp. cf lepida and D. texensis. Levels of variation in mtDNA from C. lepida in the Sabinal River and D. serena in the Frio and Sabinal rivers were comparable to or considerably lower than values documented for populations of several threatened or endangered cyprinids. Estimates of Nef for C. lepida in the Frio River and C. sp. cf lepida in the Nueces River were low, suggesting that adaptive genetic variation through time may be compromised. Of all populations sampled, only D. texensis in the Nueces River appears at present to be genetically stable demographically. An unexpected finding was two individuals resembling C. lepida in the Frio River with a haplotype referable to C. sp. cf lepida; the origin of these individuals is unknown. Two other individuals resembling C. lepida but with haplotypes of mtDNA referable to C. venusta were found in the Frio River and presumably represent relatively recent hybrids. Results of our study indicate that C. lepida, C. sp. cf lepida, and D. serena in the upper Nueces River basin, especially in the Sabinal River drainage, are at appreciable genetic risk

Do insect outbreaks reduce the severity of subsequent forest fires?

Understanding the causes and consequences of rapid environmental change is an essential scientific frontier, particularly given the threat of climate- and land use-induced changes in disturbance regimes. In western North America, recent widespread insect outbreaks and wildfires have sparked acute concerns about potential insect-fire interactions. Although previous research shows that insect activity typically does not increase wildfire likelihood, key uncertainties remain regarding insect effects on wildfire severity (i.e., ecological impact). Recent assessments indicate that outbreak severity and burn severity are not strongly associated, but these studies have been limited to specific insect or fire events. Here, we present a regional census of large wildfire severity following outbreaks of two prevalent bark beetle and defoliator species, mountain pine beetle (Dendroctonus ponderosae) and western spruce budworm (Choristoneura freemani), across the US Pacific Northwest. We first quantify insect effects on burn severity with spatial modeling at the fire event scale and then evaluate how these effects vary across the full population of insect-fire events (n = 81 spanning 1987-2011). In contrast to common assumptions of positive feedbacks, we find that insects generally reduce the severity of subsequent wildfires. Specific effects vary with insect type and timing, but both insects decrease the abundance of live vegetation susceptible to wildfire at multiple time lags. By dampening subsequent burn severity, native insects could buffer rather than exacerbate fire regime changes expected due to land use and climate change. In light of these findings, we recommend a precautionary approach when designing and implementing forest management policies intended to reduce wildfire hazard and increase resilience to global change

Mantle plume-midocean ridge interaction : geophysical observations and mantle dynamics

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 1996.Includes bibliographical references.by Garrett Tetsuo Ito.Ph.D