4,346 research outputs found
Measurements of pressures on the tail and aft fuselage of an airplane model during rotary motions at spin attitudes
An investigation was conducted in the Langley Spin Tunnel to measure the pressures on the surface of the horizontal and vertical tail and the aft fuselage of an aircraft model. The pressures were measured on a model of a proposed Australian Primary Trainer airplane configuration while the model was rotating at spinning attitudes. The test results indicate that the presence of the horizontal tail adversely modifies the surface pressure on the vertical tail. The presence of the wing also adversely modifies the pressures on the horizontal and vertical tails
Agility Measures Related to Game Performance of NCAA Baseball Pitchers
Like most kinetic chains in athletic performance, the baseball pitching motion begins with the muscles of the legs and continues progressively through the torso, shoulders, and arms. Similarities are noted between the baseball pitching motion and the kinetic chain employed in agility tests that involve acceleration, deceleration, and change of direction measures of agility. Purpose: The purpose of this investigation was to determine pre-season agility in NCAA pitchers and to relate these measures to regular season pitching performance. Methods: NCAA Division II pitchers (n=10, age 20.2 ± 1.9 yrs., weight 83.8 ± 10.3 kg, height 1.85 ± 0.48 m) volunteered as study subjects. A previously described laser-timed 60-yd shuttle run (“JJ Shuttle”) provided average speeds for four contiguous agility segments (S1, S2, S3, and S4 of 10, 10, 20, and 20 yds., respectively), as well as Total Shuttle Run (TSR). Statistical measures obtained from regular season games (n=48), including Runs (R), Hits (H), Earned Runs (ER), Base-on-Balls (BB), and Strikeouts (SO), each normalized for innings pitched, provided evidence of game pitching performance. Pearson’s Correlation Coefficient determined the relationship of average agility speeds to pitching performance. Results: Analysis identified significant correlations (p\u3c.05) between S1, S2, and TSR and normalized SO (r=0.77, r=0.73, and r=0.87, respectively); S3 and S4 were insignificant (r=0.42 and r=0.59, respectively). Additionally, a significant correlation (p\u3c.05) was identified between S3 and BB (r=0.67). Conclusion: Results of this study suggest that better agility may lead to selected improvements in game performance in NCAA Division II baseball pitchers
Ariel - Volume 12 Number 1
Executive Editors
David G. Polin
Larry H. Pastor
Business Manager
Alex Macones
Jean Lien
Editorial Page Editor
Sam Markind
Photography Editors
Ken Yonemura
Lois Leach
Sports Editor
Todd Hoove
The Goldberger-Treiman Discrepancy in SU(3)
The Goldberger-Treiman discrepancy in SU(3) is analyzed in the framework of
heavy baryon chiral perturbation theory (HBChPT). It is shown that the
discrepancy at leading order is entirely given by counterterms from the order
p^3 Lagrangian, and that the first subleading corrections are suppressed by two
powers in the HBChPT expansion. These subleading corrections include meson-loop
contributions as well as counterterms from the order p^5 Lagrangian. Some
one-loop contributions are calculated and found to be small. Using the three
discrepancies (pi-N-N, K-N-Lambda and K-N-Sigma) which can be extracted from
existing experimental data, we find that the HBChPT calculation favors the
smaller g(pi-N-N) values obtained in recent partial wave analyses.Comment: 16 pages,2 figures, revte
A Marine Incursion in the Lower Pennsylvanian Tynemouth Creek Formation, Canada:Implications for Paleogeography, Stratigraphy and Paleoecology
We document the occurrence of a marine bed, and its associated biota, in the Lower Pennsylvanian (Langsettian) Tynemouth Creek Formation of New Brunswick, and discuss its implications for paleogeography, stratigraphy, and paleoecology. This is only the second marine interval found in the entire Pennsylvanian fill of the Maritimes Basin of Canada, the other being recently found in the broadly same-age Joggins Formation of Nova Scotia. Evidence for the new marine transgression comprises an echinoderm-rich limestone that infills irregularities on a vertic paleosol surface within the distal facies of a syntectonic fluvial megafan formed under a seasonally dry tropical climate. Gray, platy ostracod-rich shales and wave-rippled sandstone beds that directly overlie the marine limestone contain trace fossils characteristic of the Mermia Ichnofacies, upright woody trees, and adpressed megafloras. This association represents bay-fills fringed by freshwater coastal forests dominated by pteridosperms, cordaites, and other enigmatic plants traditionally attributed to dryland/upland habitats. The fossil site demonstrates that marine transgressions extended farther into the interior of Pangea than has previously been documented, and may allow correlation of the Tynemouth Creek and Joggins Formations with broadly coeval European successions near the level of the Gastrioceras subcrenatum and G. listeri marine bands. It also helps explain the close similarity of faunas between the Maritimes Basin and other paleotropical basins, if transgressions facilitated migration of marine taxa into the continental interior
DWV-A lethal to honey bees (Apis mellifera): a colony level survey of DWV variants (A, B, and C) in England, Wales, and 32 states across the US
The strong association between Varroa destructor, deformed wing virus (DWV), and high overwintering colony losses (OCL) of honey bees is well established. Three DWV master variants (DWV-A, -B, and -C) have been described, and their role in colony mortality remains an open question. Therefore, the aim of this study is to investigate the seasonal prevalence, viral load, and changing distribution of the three DWV master variants within honey bee colonies from England, Wales, and 32 states across the United States. Here, we report that in 2016, DWV-B was prevalent (100%, n = 249) and dominant (95%) in England and Wales, compared to the US. (56%, n = 217 and 23%, respectively), where DWV-A was prevalent (83%, n = 217) and dominant (63%). DWV-C was regularly detected in low viral loads (1 × 1010) in surviving colonies from all sample locations, providing further supporting evidence of DWV-A exhibiting increased virulence over DWV-B at the colony level
High Resolution X-Ray Micro-CT of Ultra-Thin Wall Space Components
A high resolution micro-CT system has been assembled and is being used to provide optimal characterization for ultra-thin wall space components. The Glenn Research Center NDE Sciences Team, using this CT system, has assumed the role of inspection vendor for the Advanced Stirling Convertor (ASC) project at NASA. This article will discuss many aspects of the development of the CT scanning for this type of component, including CT system overview; inspection requirements; process development, software utilized and developed to visualize, process, and analyze results; calibration sample development; results on actual samples; correlation with optical/SEM characterization; CT modeling; and development of automatic flaw recognition software. Keywords: Nondestructive Evaluation, NDE, Computed Tomography, Imaging, X-ray, Metallic Components, Thin Wall Inspectio
Fifteen Years of Chandra Operation: Scientific Highlights and Lessons Learned
NASA's Chandra X-Ray Observatory, designed for three years of operation with a goal of five years is now entering its 15-th year of operation. Thanks to its superb angular resolution, the Observatory continues to yield new and exciting results, many of which were totally unanticipated prior to launch. We discuss the current technical status, review recent scientific highlights, indicate a few future directions, and present what we feel is the most important lesson learned from our experience of building and operating this great observatory
Nodular lymphocyte predominant hodgkin lymphoma and T cell/histiocyte rich large B cell lymphoma : endpoints of a spectrum of one disease?
In contrast to the commonly indolent clinical behavior of nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), T cell/histiocyte rich large B cell lymphoma (THRLBCL) is frequently diagnosed in advanced clinical stages and has a poor prognosis. Besides the different clinical presentations of these lymphoma entities, there are variants of NLPHL with considerable histopathologic overlap compared to THRLBCL. Especially THRLBCL-like NLPHL, a diffuse form of NLPHL, often presents a histopathologic pattern similar to THRLBCL, suggesting a close relationship between both lymphoma entities. To corroborate this hypothesis, we performed gene expression profiling of microdissected tumor cells of NLPHL, THRLBCL-like NLPHL and THRLBCL. In unsupervised analyses, the lymphomas did not cluster according to their entity. Moreover, even in supervised analyses, very few consistently differentially expressed transcripts were found, and for these genes the extent of differential expression was only moderate. Hence, there are no clear and consistent differences in the gene expression of the tumor cells of NLPHL, THRLBCL-like NLPHL and THRLBCL. Based on the gene expression studies, we identified BAT3/BAG6, HIGD1A, and FAT10/UBD as immunohistochemical markers expressed in the tumor cells of all three lymphomas. Characterization of the tumor microenvironment for infiltrating T cells and histiocytes revealed significant differences in the cellular composition between typical NLPHL and THRLBCL cases. However, THRLBCL-like NLPHL presented a histopathologic pattern more related to THRLBCL than NLPHL. In conclusion, NLPHL and THRLBCL may represent a spectrum of the same disease. The different clinical behavior of these lymphomas may be strongly influenced by differences in the lymphoma microenvironment, possibly related to the immune status of the patient at the timepoint of diagnosis
- …
