3,964 research outputs found
MHD mode conversion in a stratified atmosphere
Mode conversion in the region where the sound and Alfven speeds are equal is
a complex process, which has been studied both analytically and numerically,
and has been seen in observations. In order to further the understanding of
this process we set up a simple, one-dimensional model, and examine wave
propagation through this system using a combination of analytical and numerical
techniques. Simulations are carried out in a gravitationally stratified
atmosphere with a uniform, vertical magnetic field for both isothermal and
non-isothermal cases. For the non-isothermal case a temperature profile is
chosen to mimic the steep temperature gradient encountered at the transition
region. In all simulations, a slow wave is driven on the upper boundary, thus
propagating down from low-beta to high-beta plasma across the mode-conversion
region. In addition, a detailed analytical study is carried out where we
predict the amplitude and phase of the transmitted and converted components of
the incident wave as it passes through the mode-conversion region. A comparison
of these analytical predictions with the numerical results shows good
agreement, giving us confidence in both techniques. This knowledge may be used
to help determine wave types observed and give insight into which modes may be
involved in coronal heating.Comment: 7 pages, 5 figure
Do High School Exit Exams Influence Educational Attainment or Labor Market Performance?
State requirements that high school graduates pass exit exams were the leading edge of the movement towards standards-based reform and continue to be adopted and refined by states today. In this study, we present new empirical evidence on how exit exams influenced educational attainment and labor market experiences using data from the 2000 Census and the National Center for Education Statistics' Common Core of Data (CCD). Our results suggest that the effects of these reforms have been heterogeneous. For example, our analysis of the Census data suggests that exit exams significantly reduced the probability of completing high school, particularly for black students. Similarly, our analysis of grade-level dropout data from the CCD indicates that Minnesota's recent exit exam increased the dropout rate in urban and high-poverty school districts as well as in those with a relatively large concentration of minority students. This increased risk of dropping out was concentrated among 12th grade students. However, we also found that Minnesota's exit exam lowered the dropout rate in low-poverty and suburban school districts, particularly among students in the 10th and 11th grades. These results suggest that exit exams have the capacity to improve student and school performance but also appear to have exacerbated the inequality in educational attainment.
A Eutrophication Model of the White River Basin Above Beaver Reservoir in Northwest Arkansas
With national interest focused on man’s ever increasing degradation of the waters in this nation, it is clearly evident that an accurate assessment of all parameters influencing water quality needs to be made. Moreover, nutrient levels and budgets reflecting eutrophication trends are important parameters in the overall factors effecting water quality in lakes and reservoirs. The ability to predict future eutrophication levels will greatly enhance the retardation of the eutrophication process. Through mathematical simulation of this process, eutrophication can be analyzed and intelligent decisions regarding water quality management can be made
Traceability-based change management in operational mappings
This paper describes an approach for the analysis of changes in model transformations in the Model Driven Architecture (MDA). Models should be amenable to changes in user requirements and technological platforms. Impact analysis of changes can be based on traceability of model elements. We propose a model for generating trace links between model elements and study scenarios for changes in source models and how to identify the impacted elements in the target model
Paper Session II-B - Commercial Launch Services - The key to the Capital Markets for Space Projects
Space projects have been experiencing crippling difficulties in getting access to private capital markets. As launch operations move from public management to the tougher \u27real world 1 , competition will generate increased access to space, better launch operations and lower project costs. These changes will dramatically improve the cash flow projections and risks of space projects, enabling them to gain access to capital.
This paper will give examples of how launch delays can devastate the rate of return on a project. It will also illustrate how fast turnaround can be used to reduce costs and the effect of competition on payload prices
Nature and design : assisting with the healing process
The purpose of this thesis is to explore the literature on healthcare environments, discuss the definition of a healing environment and the components that define the space and to gain a broader understanding of the relation between the built environment and its impact on patient and staff health outcomes. Another purpose of this thesis is to design a healing environment with a holistic approach integrating the concept of the physical environment as a therapeutic resource and the use of nature in the healing process. Based on observation and analysis, Mary Greeley Medical Center in Ames, Iowa does not have a healing environment conducive to physical, emotional and spiritual healing. Such an environment for patients, families and staff at Mary Greeley Medical Center will provide a peaceful and relaxing escape from the stresses of pain, suffering, illness and the work environment. The literature review for this study addresses healing environments and how incorporating nature and healing gardens into healthcare facilities provides therapeutic benefits and assists with the healing process. The literature review also addresses built environments in relation to health outcomes for both patients and staff. Also included is general information about health care facilities addressing issues such as sustainability and marketing opportunities. An analysis of the existing site was based on observations and photographic documentation. A survey was also distributed and completed by those who use Mary Greeley Medical Center. All of this information was considered for the design and construction of the proposed healing environment for Mary Greeley Medical Center. The study resulted in invaluable information for providing design solutions to ensure that healthcare environments created by interior designers, architects and hospital administrators contribute to and promote the healing process
Reproductive neuroendocrine function in the mare as reflected in the intercavernous sinus during ovulatory, anovulatory, and transitional seasons
We hypothesized that marked reductions in secretion of luteinizing hormone (LH) during transitional and anovulatory periods can be accounted for by similar reductions in hypothalamic gonadotropin-releasing hormone (GnRH) secretion. Catheters were inserted surgically into the intercavernous sinus (ICS) of seven non-pregnant mares via the superficial facial vein during the ovulatory season (August 12-23), fall transition (November 15-30), the anovulatory season (January 19 - February 1) and spring transition (March 24 - May 12). Catheter placement was confirmed and standardized in each mare by lateral radiography. Ovarian status was monitored throughout the study by transrectal ultrasonography and serum concentrations of progesterone. During the breeding season, ICS blood samples were collected at 5-min intervals for 8 h when the dominant follicle reached approximately 35 mm and estrous behavior was observed. All mares ovulated within 5 d after sampling, except one mare who ovulated < 24 h before sampling. During the fall, mares were anovulatory (n = 5) or had a final ovulation within 5 d following intensive sampling (n = 2). Winter anovulation sampling was performed when all mares were anovulatory. During spring transition, each mare was sampled just before the second ovulation of the season. Similar to the ovulatory season, mares were sampled when the dominant, preovulatory follicle reached approximately 35 mm and estrous behavior was observed. Mean concentrations of LH were markedly higher (P < 0.01) during the breeding season than during all other seasons. Lower mean concentrations of LH in the fall transition, winter anovulation and spring transition sampling periods occurred coincident with a similar reduction (P < 0.01) in amplitude of LH pulses. Unexpectedly, neither the frequency (pulse/8 h) of LH pulses, frequency and amplitude of GnRH pulses, nor mean concentrations of GnRH differed among seasons. In addition, there were no differences observed due to season in mean concentrations of FSH or amplitude of FSH pulses. However, a small but significant (P < 0.05) reduction in the frequency of FSH pulses was observed during fall transition compared to all other seasons. In summary, contrary to accepted dogma, these results indicate that the photoperiodic initiation of seasonal anovulation in the mare is mediated at the level of the anterior pituitary, and appears to occur through a dampening of gonadotroph responsiveness to an unchanging pattern and magnitude of GnRH secretion
Feasibility Study for a Desktop Publishing Lab for Education and Industry at Pittsburg State University
A desktop publishing lab to serve education and industry involves a multiple of problems not the least of which is defining what it is and how it is used by individuals, business and the printing industry. Desktop publishing is a method whereby an individual can at will produce computer generated material, at his or her desktop, that is camera-ready for reproducing in a chosen manner and then distributed for the public\u27s information. The term was coined in 1985 by Paul Brainerd, president and founder of Aldus Corporation, makers of one of the first pagination programs, PageMaker
Teacher Feedback Regarding Principal Performance
This study was conducted to address the need for teacher feedback regarding principal performance at Casey-Westfield Community Unit School District C-4. It examined current uses of critical elements and determined which elements should be used to compose a model program utilizing teacher feedback regarding principal performance. A program which could be used in District C-4 to provide teacher feedback to principals regarding their performance was developed. The program was developed by determining (a) applicable critical elements, (b) type of feedback to be obtained, (c) procedures for administration of the program, (d) procedures for assessment of data, (e) selection of facilitator, and (f) desired impact on the principal.
The critical elements which should be used to compose a model program utilizing teacher feedback regarding principal performance were found in the National Association of Elementary School Principals\u27 publication Standards for Quality Elementary and Middle Schools (1996). The identified standards were grouped into six critical elements: (a) organization, (b) leadership, (c) curriculum and instruction, (d) staff development, (e) school climate, and (f) assessment.
The District C-4 program for providing teacher feedback regarding principal performance was designed to use the previously identified critical elements. Feedback should be collected through the use of a survey with a rating scale and both required and optional narrative comments. The program should be conducted in May of each year. A teacher should be selected as the facilitator to distribute the feedback instrument to teachers via mailboxes and collect the instruments after a specified amount of time. The principal should be responsible for assessing the data by tabulating the results of all scaled items and summarizing the narrative comments by critical elements for easier analysis.
Other schools interested in providing principals with teacher feedback regarding principal performance are encouraged to first identify critical elements. Those critical elements should reflect state and national standards for learning. The research on what makes a quality school is comprehensive and should be utilized in any school improvement effort. After critical elements are identified, a program can be developed utilizing this study as a reference
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