5,621 research outputs found
General F-theory models with tuned symmetry
We construct a general form for an F-theory Weierstrass model over a general
base giving a 6D or 4D supergravity theory with gauge group
and generic associated matter, which includes the matter
content of the standard model. The Weierstrass model is identified by
unHiggsing a model with gauge symmetry and charges previously found by the first author. This model includes two distinct
branches that were identified in earlier work, and includes as a special case
the class of models recently studied by Cveti\v{c}, Halverson, Lin, Liu, and
Tian, for which we demonstrate explicitly the possibility of unification
through an unHiggsing. We develop a systematic
methodology for checking that a parameterized class of F-theory Weierstrass
models with a given gauge group and fixed matter content is generic
(contains all allowed moduli) and confirm that this holds for the models
constructed here.Comment: 36 pages, LaTe
Flight calibration of compensated and uncompensated pitot-static airspeed probes and application of the probes to supersonic cruise vehicles
Static pressure position error calibrations for a compensated and an uncompensated XB-70 nose boom pitot static probe were obtained in flight. The methods (Pacer, acceleration-deceleration, and total temperature) used to obtain the position errors over a Mach number range from 0.5 to 3.0 and an altitude range from 25,000 feet to 70,000 feet are discussed. The error calibrations are compared with the position error determined from wind tunnel tests, theoretical analysis, and a standard NACA pitot static probe. Factors which influence position errors, such as angle of attack, Reynolds number, probe tip geometry, static orifice location, and probe shape, are discussed. Also included are examples showing how the uncertainties caused by position errors can affect the inlet controls and vertical altitude separation of a supersonic transport
Ulnar Collateral Ligament Reconstruction with Traditional Docking Compared to Novel Surgical Techniques
Background: Ulnar Collateral Ligament Reconstruction (UCLR) is a surgical procedure on one of the main ligaments that provides normal stability for the elbow joint against excessive valgus stress. Damage to this ligament is common in athletes performing overhead throwing activities, primarily baseball players, due to excessive valgus stress during the throwing motion. The most common form of treatment for this type of injury is reconstructive surgery of the ligament, especially if athletes wish to return to sport participation. This type of surgery is extremely invasive and requires extensive post-operative rehabilitation in order to facilitate return to play. To date, many surgical techniques have been proposed and evaluated, but there are no conclusive comparison studies on patient outcomes following UCLR. Purpose: The purpose of this paper is to analyze previous studies on UCLR techniques and determine if there is a single superior surgical method leading to improved biomechanical outcomes and decreased failure measures. Our focused clinical question was identifying if the traditional docking technique compared to novel docking techniques during UCLR superior in relation to biomechanical outcomes and failure measures in cadaveric tissue. Methodology: The study design in this paper is a critically appraised topic. Various scholarly databases such as PubMed, MEDLINE and SportDiscus were utilized to search for studies related to UCLR surgical techniques. After an initial search, a list of fifteen relevant studies were identified. Each study was then scrutinized and evaluated to meet predetermined inclusion criteria and a minimum score of 6/9 on the PEDro scale. All studies not meeting these requirements were excluded. This left a total of five articles which were then used to answer the clinical question for this paper. The inclusion criteria involved meeting a cadaveric age of 16-60 y, objective measures of valgus testing, angular displacement, stiffness and modes of failure as post-operative outcomes. Further, we included studies that had a minimum of seven cadaver pairs tested, and studies were required to compare traditional docking to at least one novel technique. Results: All five studies involved compared at least one novel surgical technique to the docking technique. Four studies found no significant overall difference between the native and reconstructed states of any surgical technique. One study found no overall significant difference, but did identify slight differences in biomechanical properties. Discussion: All conclusions from individual studies demonstrate comparable findings between all UCLR techniques. Biomechanics, kinematics and failure modes in the acute stages following surgery in cadavers are similar between UCLR techniques. Despite all that has been done, additional research is still necessary to determine a superior surgical technique
A Study of the Home Management Program of Forty Negro Families in Washington County, Texas
Most families of Washington County, as in other places, seem unable to value money intelligently. Either they over-value it and deny themselves conveniences they can well afford, or they under-value it and spend it carelessly for things that impair more than promote their welfare.
It is the purpose of this study to analyze some of the factors related to the home management problem among the Negro families of Washington County, and to show what improvement will be made in their programs. The problems that are being discussed are here listed: (1) How the family uses its money. (2) To what extent is planning helpful? (3) What records are advisable? (4) Who shall decide the use of family funds? (5) Is it justifiable for a family to borrow money? (6) Is it wise to buy on installment plans? (7) If saving is possible, how shall it be invested
MEASURING THE LEVELS OF ATHLETIC IDENTITY AND IDENTITY FORECLOSURE OF NATIONAL ASSOCIATION OF INTERCOLLEGIATE ATHLETICS (NAIA) STUDENT-ATHLETES
During a person’s college years they are beginning to form identities and develop a sense of self. One of the most salient identities that college student-athletes identify with is their athletic identity. Numerous research studies have been conducted on the saliency of a student-athlete’s athletic identity, however the vast majority of those research studies examined student-athletes participating at the NCAA (National Collegiate Athletic Association) Division I level. This study was designed to extend the previous investigation of athletic identity and identity foreclosure among college students by focusing on athletes participating at the NAIA (National Association of Intercollegiate Athletics) level.
By utilizing previously developed scales: Athletic Identity Measurement Scale (AIMS) and the Extended Objective Measure of Ego-Identity Status (EOM-IS), this study assessed a sample of male and female college student-athletes’ AIMS and EOM-IS levels in order to investigate their levels of athletic identity and identity foreclosure. Further, this study looks to determine if there is a significant variance in AIMS and EOM-IS levels based on selected independent variables: grade classification, sport, scholarship and non-scholarship athletes, revenue generating and non-revenue generating sports. Participants in this study were student-athletes at Asbury University located in Wilmore, KY which is a NAIA institution
Shadow, Skin, and Surface; Examining the Work of Viviane Sassen
Viviane Sassen is a Dutch fashion photographer, whose personal work feature people from African descent. Through the employment of the equatorial light, her models’ personal identities and faces are left in the shadow, their dark skin rendered “just” black, depicting the sitters invisible and without personal recognition.
In this thesis I offer an alternative to reading her work whose praise always stay on the surface; I examine her work in relation to the historical and geographical location, offer an analysis to the ontology of the shadow in photography, and examine the treatment of the surface of Sassen’s models
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A comparison of stage-specific all-cause mortality between testicular sex cord stromal tumors and germ cell tumors: results from the National Cancer Database.
BackgroundTesticular sex cord stromal tumors (SCSTs) are managed similarly to germ cell tumors (GCTs); however, few studies have directly compared outcomes between these tumor types. Using the National Cancer Database (NCDB), we sought to compare overall and stage-specific all-cause mortality (ACM) between SCSTs versus GCTs.MethodsNCDB was queried for patients diagnosed with SCSTs and GCTs between 2004 and 2013. Descriptive statistics were used to compare sociodemographic and clinical characteristics between groups. Univariable and multivariable Cox proportional hazards regression analyses were used to assess associations with ACM.ResultsWe identified 42,192 patients diagnosed with testicular cancer between 2004 and 2013, with 280 having SCSTs and 41,912 patients having GCTs. Median age for SCSTs and GCTs was 45 (interquartile range [IQR] 34-59) and 34 (IQR 27-43), respectively (p < 0.001). Median follow-up was 39 and 52 months, respectively. Overall, patients with SCSTs had greater risk of ACM compared to those with GCTs (HR 1.69, 95% CI 1.14-2.50). Private insurance, greater education, and fewer comorbidities were associated with reduced risk of ACM (p < 0.05 for all). Among those with stage I disease, tumor type was not associated with ACM on multivariable analysis. Among those with stage II/III disease, patients with SCSTs had increased risk of ACM compared to patients with GCTs (HR 3.29, 95% CI 1.89-5.72).ConclusionsPatients with advanced SCSTs had worse survival outcomes compared to those with advanced GCTs. These data suggest a need for further investigation to ascertain effective management recommendations for SCSTs
Handling Qualities and Trajectory Requirements for Terminal Lunar Landing, as Determined from Analog Simulation
Trajectory requirements for terminal lunar landing from analog simulation of spacecraf
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