1,507 research outputs found
Wavefront error sensing for LDR
Wavefront sensing is a significant aspect of the LDR control problem and requires attention at an early stage of the control system definition and design. A combination of a Hartmann test for wavefront slope measurement and an interference test for piston errors of the segments was examined and is presented as a point of departure for further discussion. The assumption is made that the wavefront sensor will be used for initial alignment and periodic alignment checks but that it will not be used during scientific observations. The Hartmann test and the interferometric test are briefly examined
THE ROLE OF CULTURE IN AGRICULTURAL EDUCATION: A synthesis of research
Culture is studied across many different disciplines and is viewed as a topic of great and valuable interest within research. Agricultural education has come to recognize the value of embracing a multicultural attitude and the need for recruitment of culturally diverse individuals. While definitions of culture can vary from individual to individual, understanding the degree which a topic has been researched within a discipline is necessary in order to know what direction future research should take. Therefore, this study presents the findings of research on culture within the Journal of Agricultural Education from 1960-2015. This study’s findings indicate that culture, as defined as a way of life that outlines how an individual acts, perceives, and believes, has been researched on a very limited basis within the Journal of Agricultural Education. However, findings also indicate that many tenets of culture have been researched and include diversity, multicultural education, inclusion, and teacher preparation. These findings lead to recommendations to expand the research within the topic of culture to include social aspects of culture and youth cultures
Mu and Tau Neutrino Thermalization and Production in Supernovae: Processes and Timescales
We investigate the rates of production and thermalization of and
neutrinos at temperatures and densities relevant to core-collapse
supernovae and protoneutron stars. Included are contributions from electron
scattering, electron-positron annihilation, nucleon-nucleon bremsstrahlung, and
nucleon scattering. For the scattering processes, in order to incorporate the
full scattering kinematics at arbitrary degeneracy, the structure function
formalism developed by Reddy et al. (1998) and Burrows and Sawyer (1998) is
employed. Furthermore, we derive formulae for the total and differential rates
of nucleon-nucleon bremsstrahlung for arbitrary nucleon degeneracy in
asymmetric matter. We find that electron scattering dominates nucleon
scattering as a thermalization process at low neutrino energies
( MeV), but that nucleon scattering is always faster
than or comparable to electron scattering above MeV. In
addition, for g cm, MeV, and
neutrino energies MeV, nucleon-nucleon bremsstrahlung always
dominates electron-positron annihilation as a production mechanism for
and neutrinos.Comment: 29 pages, LaTeX (RevTeX), 13 figures, submitted to Phys. Rev. C. Also
to be found at anonymous ftp site http://www.astrophysics.arizona.edu; cd to
pub/thompso
Determining Force Field Parameters Involved with Metal Organic Framework Synthesis
Metal organic frameworks (MOFs) are synthetic materials made of a cage-like lattice with consistently spaced pores. The size of these pores are the defining characteristic of a MOF, as it determines which gases are allowed to pass through and which can be trapped. Examples of their potential use can be greenhouse gas sequestration or storage. Currently, the synthesis of MOFs is based on trial-and-error, and the successes are not well understood. We are working on building the theoretical framework that describes how a particular MOF, MIL-101, comes together during synthesis. Our initial approach was to simulate the possible reactions with chemical kinetics through Cantera (a software suite that works through Python). To do this, a list of all possible intermediates with their thermodynamic properties is required. Another approach is to calculate the chemical force field potentials, and simulate how the atoms themselves behave during the synthesis process. For both purposes we minimized the energy of the structure of one known intermediate, called ML3 (a metal core with three linkers) through Assisted Model Building with Energy Refinement (AMBER) and with electronic structure calculations through Gaussian 09. In the end, the parameters that defined this minimized structure of ML3 were found. These can be used further to build the MIL-101 mechanism for use in Cantera, as well as the force field simulations
Levator claviculae: a case report and review of the literature
The levator claviculae is an uncommon anatomical variant found in the posterior
cervical triangle. In this report we present a 78-year-old man with this
muscular variation, which was found during gross anatomical dissection. While
sites of insertion and origin have been variable, in the present case the muscle
originated from the left transverse processes of C3 and C4, and inserted onto
the lateral third of the ipsilateral clavicle. Clinical considerations of this variant
anatomy are of interest, as they may present in patients as a supraclavicular
mass and may also mimic pathology on cross-sectional imaging
Biological Investigation of Wing Motion of the Manduca Sexta
An investigation was conducted assessing the feasibility of reproducing the biological flapping motion of the wings of the hawkmoth, Manduca sexta (M.sexta) by artificially stimulating the flight muscles for Micro Air Vehicle research. Electromyographical signals were collected using bipolar intramuscular fine wire electrodes inserted into the primary flight muscles, the dorsal longitudinal and dorsal ventral muscles, of the adult M.sexta. These signals were recorded and associated with wing movement using high speed video. The signals were reapplied into the corresponding muscle groups with the intention of reproducing similar flapping motion. A series of impulse signals were also directed into the primary flight muscles as a means of observing muscle response through measured forewing angles. This study pioneered electromyographic research on M.sexta at the Air Force Institute of Technology with tests conducted with fine wire electrodes. Through this process, the research showed the deformational structural changes that take place when a wing is removed from an insect and proved that muscular stimulation is a viable method for generating wing movement. This study also assisted in developing an understanding related to the role that a thorax-like fuselage could play in future micro aircraft designs. This study has shown that partial neuromuscular control of the primary flight muscles of M.sexta is possible with electrical stimulants which could be used to directly control insect flight
Fat herniation through the canal of Schwalbe
The authors report a case of fat herniation through the canal of Schwalbe noted in a female cadaver during abdominopelvic dissection. Perineal hernias are rare hernias, and herniations through the hiatus of Schwalbe represent a rare posterior lateral perineal hernia. While these hernias are extremely rare, anatomists and surgeons should be aware of them, and the clinical significance and manifestations which may occur with these hernias
Student Educational Responsibility: ACase Study of Emotional Response to International Education
This study focuses on student emotional reactions toward new events or stimuli within a learner-centered, international education course. Using the primary tenets of appraisal theory, researchers analyzed novel stimuli, as identified by the students, and students’ emotional reactions toward each stimulus. Participants were immersed into two separate Scottish island communities for a 22-day period. The primary course objective included students developing leadership skills associated with community development while working with ruralScottish communities.Results indicated that students experienced a wide range of emotions associated with multiple stimuli. Identified stimuli were dichotomized into two categories, the international immersion process as well as the shift in educational responsibility from instructor to student. Emotional magnitude and coping mechanisms differed from student to student. Post international study reflections indicated that students experienced a deeper learning experience when using a learner-centered approach to international education
Transsylvian selective amygdalohippocampectomy for treatment of medial temporal lobe epilepsy: Surgical technique and operative nuances to avoid complications
Background:
A number of different surgical techniques are effective for treatment of drug-resistant medial temporal lobe epilepsy. Of these, transsylvian selective amygdalohippocampectomy (SA), which was originally developed to maximize temporal lobe preservation, is arguably the most technically demanding to perform. Recent studies have suggested that SA may result in better neuropsychological outcomes with similar postoperative seizure control as standard anterior temporal lobectomy, which involves removal of the lateral temporal neocortex.
Methods:
In this article, the authors describe technical nuances to improve the safety of SA.
Results:
Wide sylvian fissure opening and use of neuronavigation allows an adequate exposure of the amygdala and hippocampus through a corticotomy within the inferior insular sulcus. Avoidance of rigid retractors and careful manipulation and mobilization of middle cerebral vessels will minimize ischemic complications. Identification of important landmarks during amygdalohippocampectomy, such as the medial edge of the tentorium and the third nerve within the intact arachnoid membranes covering the brainstem, further avoids operator disorientation.
Conclusion:
SA is a safe technique for resection of medial temporal lobe epileptogenic foci leading to drug-resistant medial temporal lobe epilepsy
A wandering spleen presenting as a pelvic mass: case report and review of the literature
Wandering spleens are rare clinical entities found more commonly in females.
We report a young female patient found to harbour a pelvic spleen. The literature
regarding this rare ectopia is reviewed. The wandering spleen should be
considered in the differential diagnosis of pelvic masses
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