Disease resistance in red clover leaves

Imperial Users onl

Geochemical prospecting studies for beryllium in Central and East Africa

Imperial Users onl

Imaging of the Head and Neck following Radiation Treatment

Squamous cell carcinoma of the head and neck occurs in approximately 40,000 patients annually in the United States and is often treated with radiation therapy. Radiological studies are obtained following treatment for head and neck malignancies to assess for recurrent tumor, posttreatment changes, and associated complications. Radiation treatment creates a difficult clinical picture for oncologists, head and neck surgeons, neuroradiologists, and neuropathologists. As post-treatment imaging studies are often discussed at radiology/pathology working conferences, knowledge of the imaging appearance of radiation-associated changes in the head and neck and the terminology used by neuroradiologists may not only aid in interpretation of the pathologic specimen, but also assist in communications with neuroradiologists and referring clinicians

The relationship between literacy outcomes & social-contextual variables for students in low and middle income countries

This dissertation explores the relationship between social-contextual variables and literacy outcomes in Sierra Leone. To ensure the quality of the review, the assessment tool utilized to measure literacy outcomes, in this case, the Early Grade Reading Assessment (EGRA), will be evaluated for appropriateness, using an examination of descriptive statistics, Rasch methodology, and correlations with social-contextual variables. While the assessment may be of acceptable quality, student reading levels are low. However, despite these low scores, students’ achievement was potentially positively impacted by reading with parents and the language spoken at home and at school

Juvenile temperature regulation in Apis mellifera (Honey bee) and the impacts of brood temperature requirements on the colony

Little is known about the energetic costs to insects of raising young. Honey bees collectively raise young, or brood, through a series of complex behaviors that appear to accelerate and synchronize the timing of brood maturation. These include maintaining the brood nest at warmer and consistent temperatures and the exceptional activity of heater bees. The temperature at which juvenile insects are raised can profoundly affect their development. Apis mellifera (Honey bees) cope with temperature-dependent development via social behavior that maintains the relatively high and constant temperatures within the nest where the brood are raised. Yet juvenile honey bee development is complex and can be categorized into egg, larvae, pupating juveniles, and pupae. Honey bees use passive and active behaviors to maintain remarkably constant brood nest temperatures, from 33 to 35°C, across a wide range of ambient temperatures. In addition to these colony-scale behaviors, a small subset of nurse bees behaves as heater bees. Heater bees contract thoracic flight muscles to generate heat, but their thoraxes reach much higher temperatures than other bees responsible for brood care, ranging between 42 and 47°C. Heater bees focus their attention on incubating individual cells by moving among brood cells and regulating the temperatures of individual eggs, larvae, and pupae. We constructed four sets of experimental hives to explore the developmental temperatures at which each juvenile stage is maintained, the energetic costs of raising juveniles, and the cost of heater bees. One set allowed us to record the temperatures of undisturbed young in the brood nest area established by the colony. The second set was designed to estimate the numerical allocation of individuals to the heater bee task. The third set was intended to contain only brood, which eliminated foraging and allowed us to quantify stored honey use when rearing juveniles at 10 and 30°C. The final set was used to measure the respiration rates and energy expenditure of individual bees displaying resting, walking, heating, and agitated behavior. We first discovered that instead of simply maintaining brood nest areas at 33-35°C, honey bees provide extraordinarily precise but different temperatures for larvae and pupae. We found that the temperature at which heater bees regulate cells is above the overall average temperature range of the brood nest. Honey bees raised larvae at 36.38±0.02°C, substantially higher and with a narrower range than what has been reported for the brood nest, 33-35°C. Honey bees raised pupae at 35.18±0.04°C, also higher than the reported temperatures for the brood nest. We further explored brood development by characterizing the developing juveniles\u27 temperature profile throughout their entire 21-day developmental cycle. We found that eggs were maintained at 36.1 ± 0.03°C, larvae at 36.2 ± 0.02°C, pupating juveniles at 35.9 ± 0.03°C, and pupae at 35.8 ± 0.03°C. All stages were significantly different from all other stages, but importantly larvae were only 0.4°C different from pupae. We then conducted another experiment with brood frames without mature bees and in incubators at 34.5°C. Without nurse bees, the temperatures of eggs, larvae, and pupae were 34.4 ± 0.04°C, 34.7 ± 0.05°C, and 34.3 ± 0.04°C, with larvae different from all other stages, and a 0.3°C difference between larvae and pupae. When compared to the 1.2°C in Chapter 1, this 0.3°C difference suggests that heater bees may be a major driver of the differences between pupae and larvae. However, the 0.4°C difference between larvae and pupae in the second experiment reported in chapter 2, vs. the 0.3°C difference, suggests that the larvae themselves may be the major contributor to the temperature difference between the life stages. Either way, our results suggest honey bee development may involve far more precise temperature during the development of juveniles than previously known. And finally, to determine the cost of maintaining juveniles at these warmer and more consistent temperatures, we compared the honey used by brood-only experimental colonies with whole-colony measurements of honey storage in the literature. We estimated that raising brood costs colonies half of their annual energy budgets stored as honey, or approximately 43.7±0.9 kg·yr-1. We estimated that roughly 2% of colony individuals perform the task of heater bee. Respiration rates of heater bees (19 mW) were more than those of resting bees (8 mW) but similar to those of walking bees (20 mW) and about half of those that were agitated (46 mW). The energetic cost of heating was more than an order of magnitude lower than reported values for the energetic cost of flying. By integrating data from our experimental hives, we estimate that the annual cost of raising brood is quite high; however, we estimate that heater bee behavior and physiology, though extreme, may require only about 7% of the annual honey stored by a colony. Instead of simply maintaining brood nest areas at 33-35°C, honey bees provide extraordinarily precise but different temperatures for larvae and pupae. We do not know if these differences ultimately affect development, but they suggest that honey bees may exert far more precise control over the temperatures of their juveniles than previously known, which comes at a high cost at the colony level (macroeconomic), but a surprisingly low cost at the individual (microeconomic) heater bee level

Ampoule sealing apparatus and process

An apparatus and process for sealing fused quartz ampoules housing a semiconductor growth charge under vacuum is described. An elongated fused quartz ampoule having an enlarged diameter open end and a reduced diameter closed end is vertically retained in a vacuum assembly. A semiconductor charge is disposed within the reduced diameter portion of the ampoule. A quartz plug of substantially the same diameter as the reduced diameter portion is suspended within the open and of the ampoule via a rotary vacuum feed. After evacuation of the ampoule a plug is lowered into the reduced diameter area and sealed therein while maintaining the vacuum on the ampoule. The charged ampoule area is then separated from the remaining structure by breaking along the scored line

Reusable thermal cycling clamp

A reusable metal clamp for retaining a fused quartz ampoule during temperature cycling in the range of 20 deg C to 1000 deg C is described. A compressible graphite foil having a high radial coefficient of thermal expansion is interposed between the fused quartz ampoule and metal clamp to maintain a snug fit between these components at all temperature levels in the cycle

African American Girls' Ideal Dating Relationship Now and In the Future and Factors that Shape These Perceptions

The quality of dating relationships in adolescence can have long lasting effects on identity development, self esteem, interpersonal skills, and shape values and behaviors related to intimate relationships and risk behaviors. However, little is understood about how adolescents view their ideal partner and what implications these perceptions may have for romantic relationships. In fact, research suggests that over 400,000 adolescents have been victims of serious dating violence at some point in their lives. Among African American adolescents, religion may be particularly salient in romantic relationships. Religious organizations not only provide a place for seeking spiritual guidance and social interactions, but also provide unifying morals, beliefs, and practices for African American families. In this dissertation, three studies where conducted. In Study 1 participants' self- identified, defined and vividly described 8 major characteristics, good communication, honesty, trust, respect, compromise, understanding, individuality, and self-confidence, of a healthy relationship. In Study 2 several themes emerged in comparing girls' perceptions of an ideal dating relationship in high school with their perceptions of the ideal future relationship: (1) having a partner who shared similar education and career plans, (2) `best friend' qualities such as respect, trust, and honesty, (3) importance of family in identifying an ideal relationship, and (4) temporariness of high school relationships. Study 3 findings suggest that the influence of religion in the lives of adolescents can be found in several domains. These included whether to become sexually active, choosing a partner based on religious affiliation and issues of sexual orientation. Interestingly, girls also felt that, despite the sanctity of marriage, women should not stay in unhealthy or harmful relationships. Dating violence prevention curricula focus on helping girls identify unhealthy or abusive relationships and provide strategies to help them leave these relationships. More programs are needed to instill in girls the values and characteristics of healthy relationships. Early education and modeling of healthy teen dating relationships will help educators, practitioners and advocates empower girls so they are more likely to develop healthy dating relationships and less likely to experience harm in their dating relationships

A sense of community and community change: an ethnographic study of a contemporary Louisiana juke joint as it compares to historical literature on the subject

The rural juke joint is a phenomenon that has been mentioned quite frequently in literature pertaining to blues music, but has not received the amount of scholarly attention that it deserves. This social institution is an integral part of the Mississippi Delta’s cultural landscape. Over time, it has developed a dual reputation as a fun place for weekend entertainment, and also a dangerous place for sin and vice. Using qualitative methods, this thesis explores a modern-day juke joint located in Waterproof, Louisiana, a small town in the northeast part of the state. It is the goal of this research to show how this particular establishment, The Disco 86 Lounge, compares to narratives and other historical literature written about juke joints in the early part of the twentieth century. In doing so, it addresses broader issues relating to changes in the surrounding community and landscape, such as out-migration and economic decline. This thesis also seeks to understand what the bar means to this local community. By using techniques such as ethnographic interviews and participant observation, I focus on the social activities of the local residents and the roles that the bar plays in the community. I also show how its patrons use this gathering place to form a meaningful sense of place and identity. Overall, this thesis provides a holistic picture of the social, historical, and cultural aspects surrounding this contemporary Delta juke joint

Magnetometer with miniature transducer and automatic transducer scanning apparatus

Magnetometer is simple to operate and has fast response. Transducer is rugged and flat and can measure magnetic fields as close as 0.08 mm from any relatively flat surface. Magnetometer has active region of approximately 0.64 by 0.76 mm and is capable of good spatial resolution of magnetic fields as low as 0.02 Oe (1.6 A/m)