Impact of student teaching experiences, personal demographics, and selected factors on the decisions of pre-service agricultural education teachers to enter into teaching

With numerous openings in the agricultural education field and shortages constantly occurring, a common question is asked, Why are pre-service teachers not teaching? . This study sought to help answer this question by investigating the impact of the student teaching experience upon certified agricultural education graduates. In addition to the student teaching experience, personal demographics and selected factors were investigated to add insight into the problem of pre-service agricultural education teachers not teaching. A two-phase descriptive survey methodology was implemented to collect data from the population, which consisted of 75 pre-service agricultural education students from Delaware Valley College, Pennsylvania State University, University of Delaware, and West Virginia University. Responses from the phase one mail survey were used to formulate the phase two questionnaire. Responses from the phase two questionnaire were tabulated to measure the impact of the student teaching experience, personal demographics, and selected factors upon the graduate\u27s decision to teach

Doctor of Philosophy

dissertationCosmic radiation was discovered in 1912. This year, the 100th anniversary of the discovery, marks not only the major progress that has been made in understanding these particles, but also the remaining questions about them. Questions about their sources, acceleration mechanisms, propagation and composition are still unanswered. There are only two experiments currently running that have the ability to study cosmic rays in the Ultra High Energy (E > 1018'0 eV) regime. The Telescope Array studies Ultra High Energy Cosmic Rays (UHECRs) using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated by a primary cosmic ray particle, while scintillator detectors measure the lateral distribution of secondary particles that hit the ground. The Middle Drum (MD) fluorescence telescope consists of 14 refurbished telescopes from the High Resolution Fly's Eye (HiRes) experiment, providing a direct link back to the HiRes experiment and data. The surface array is comprised of 507 Scintillator Detectors (SD) of a similar design as was used by the Akeno Giant Air Shower Array (AGASA), providing a link to that experiment as well. Studying TA hybrid events (events observed by both the FD and SD), makes the analysis presented in this work the lynchpin that connects the HiRes experiment to the AGASA experiment. This uniquely allows for a direct comparison between the two detection types and allows us to answer questions about the differences in the energy spectrum measurements shown by the two previous experiments. Furthermore, the hybrid analysis improves the geometrical reconstruction of the showers significantly. This provides a more accurate measurement of the energy of the primary particle and makes it possible to make an accurate prediction regarding the chemical composition of the cosmic ray particle. Historically, only the HiRes experiment and the Pierre Auger Observatory (PAO) have made significant composition measurements of UHECRs, and they report conflicting measurements. The hybrid composition measurement done in this work can be directly compared to the hybrid PAO result

The State of Water and Cell Morphology In Deep Frozen Populus

By using differential scanning calorimetry, electron microscopy, light microscopy, and freezing survival experiments, it is shown that superhardy Populus balsamifera v. Virginiana (Sarg.) is capable of withstanding liquid nitrogen (LN 2) temperatures because of the formation during cooling, at a temperature of about -30°C and cooling rates less than 30°C/hr, of aqueous glasses in the intracellular solutions. In more detail, the major findings concerning the state of intracellular water are: (1) the bulk of the intracellular contents go through an equilibrium glass transition at about -28°C during slow (<5°C/hr) cooling; (2) smaller additional amounts of intracellular material go through equilibrium glass transitions at about -47°C and -70°C; (3) as a result of the resistance to homogeneous nucleation of these glass forming intracellular solutions when they are in equilibrium with extracellular ice at<.-20°c, cooling/warming at any combination of rates from 3°C/hr to 1200°C/min between -20°c and -196°C is non-injurious to fully hardened wood; (4) death associated with quench cooling in LN2 from -15°C is correlated with the devitrification, (cold crystallization) near -90°C upon warming of the very low temperature glass forming component, followed by further devitrification of the higher temperature components, especially between -30°c and -20°c; and (5) the vacuolar compartment appears least resistant to devitrification and capable of thereby causing death even when the cytoplasm resists devitrification. In addition, it was found that when fully superhardy wood is cooled slowly (3°C/hr) after being imbibed with water (doubling total water content) massive intracellular freezing occurs. Despite the fact that total tissue water of tender Populus (summer wood) is 2x that of the artifically water loaded hardy wood on a gram H20/gram dry weight basis, tender wood cooled at 3°C/hr to -50°c does not display intracellular freezing. It is killed by -2°C. It is shown that in both tender and hardy wood <10% of water is extracellular. Thus a significant excess of extracellular water appears to cause intracellular freezing and this may be a major reason for the large water loss seen in the fall 'hardening off' of most temperature zone woody plants. It is also shown that during slow cooling, the plasma membranes of both hardy and tender Populus cells stick to and collapse the cell wall, but that these membranes stay smooth in the case of superhardy cells and wrinkle markedly in the case of tender cells. Membrane-associated particles appeared to clump in the membranes of slowly cooled tender cells but not in the slowly cooled hardy cells

Field Population and Flight Activity of Three Hippodamia Species in Eastern South Dakota

Twenty-four coccinellid species, excluding the genus Scymnus, were collected in eastern South Dakota during the 1969-70 growing seasons. Hippodamia convergens Guerin-Meneville, H. tredecimpunctata L., and H. parenthesis (Say), were the most abundant species found in alfalfa and small grains. Reproduction of H. convergens and H. tredecimpunctata occurred in alfalfa, oats, spring and winter wheat, and corn. Field observations indicated that the reproductive cycle required approximately 2½ weeks. The pea aphid, Macrosiphum pisi (Harris), the English grain aphid, M. avenae (Fabricius), and the corn leaf aphid, Rhopalosiphum maidis (Fitch), appeared to be suitable food for these 3 Hippodamia species; the brown ambrosia aphid, M. ambrosiae (Thomas), was toxic to H. tredecimpunctata. Cannibalism and interspecific predation by larvae of H. convergens and H. tredecimpunctata were observed in the field. Hymenopterous parasitism was observed in H. convergens. Adult coccinellids were found to be very flight active. Flights varied in height which was probably related to distance of flight. Habitat destruction (clipping alfalfa) and food requirements were probable cause for much flight activity. Low recapture of marked lady beetles also supported evidence of their highly mobile nature. Of the 3 Hippodamia species, H. convergens was found to be the most variable species in size and elytral maculation but was least variable in the ratio of females to males

Assessment of Potential Tooth Movement and Bite Changes With a Hard-Acrylic Sleep Appliance: A 2-Year Clinical Study

Oral appliance therapy (OAT) has been shown to successfully treat patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). However, OAT is often associated with the occurrence of side effects such as unwanted tooth movement. Positive airway pressure therapy is more commonly used to treat OSAHS, because of the reluctance to prescribe OAT as a result of these side effects. Even so, Pliska does report on tooth movement due to tongue thrusting as a result of the use of positive airway pressure. Although OAT is an effective treatment for OSAHS along with its greater compliance, long-term use of some oral appliances has been shown to result in several side effects, including tooth movement. Past studies have shown this to result in significant effects, such as craniofacial changes, anteroposterior positioning of the molars, inclination of the upper and lower incisors, and irregularity of the lower incisors. According to the American Academy of Dental Sleep Medicine’s published article on management of side effects, tooth movement (specifically occlusal changes represented by incisor changes, position of canines, decreased overjet/overbite, and altered occlusal contacts/bite changes) is one of the five significant concerns during the treatment of obstructive sleep apnea using an oral appliance. It was reported that there is a significant difference in anterior crowding using a flexible oral appliance without incisor coverage versus a rigid OA. The rigid OA demonstrated less tooth movement. Recently, new devices with proprietary computer-aided design/computer-aided manufacturing (CAD/CAM) technology have been introduced and made available to clinicians. This study aims to investigate the changes in tooth movement with a hard-acrylic rigid oral appliance, the ProSomnus® Sleep Appliance, over a 2-year period. This research project was based on an approved Internal Review Board (IRB) protocol

Determinants and Long‐Term Effects of Attendance Levels in a Marital Enrichment Program for African American Couples

Although most efficacious marital enrichment programs are multisession, few studies have explored whether outcomes differ according to session attendance, particularly among minority groups with lower than average participation in prevention programs. This study therefore investigates attendance levels and long‐term improvements in couple functioning among 164 couples participating in the Promoting Strong African American Families program. Structural equation models indicated session attendance predicted 2‐year changes for men\u27s reports of communication, commitment, and spousal support (marginally) but not for women\u27s. Individual and couple characteristics that predicted attendance levels were also identified. Results highlight distinct gender differences in the effects of sustained attendance as well as characteristics that provide early identifiers for African American couples at increased risk of low program attendance

Validation of a Model for Prediction of Percent Intramuscular Fat on Live Feedlot Cattle

A prediction model from a previous study was utilized to evaluate the degree of fit when this model is applied to an independent data set. The degree of fit was evaluated using means, regression analysis, correlation coefficient, distribution of residuals, and mean square error of prediction (MSEP). The model provided a reasonably accurate prediction of intramuscular fat with a mean bias of 0.13%. For 47.1% of the steers, percent intramuscular fat was predicted within ± 0.5%, and for 77.6% of the steers, prediction of percent intramuscular fat was made within ± 1%. Pearson product moment correlation between predicted and actual percent intramuscular fat was 0.74 (p \u3c .01), and the square root of MSEP indicated a prediction error of 0.9%