Submillimeter-wave InP Gunn devices

Recent advances in design and technology signifi- cantly improved the performance of low-noise InP Gunn devices in oscillators first at -band (110–170 GHz) and then at -band (75–110 GHz) frequencies. More importantly, they next resulted in orders of magnitude higher RF output power levels above -band and operation in a second harmonic mode up to at least 325 GHz. Examples of the state-of-the-art performance are continuous-wave RF power levels of more than 30 mW at 193 GHz, more than 3.5 mW at 300 GHz, and more than 2 mW at 315 GHz. The dc power requirements of these oscillators compare favorably with those of RF sources driving frequency multiplier chains to reach the same output RF power levels and frequencies. Two different types of doping profiles, a graded profile and one with a doping notch at the cathode, are prime candidates for operation at submillimeter- wave frequencies. Generation of significant RF power levels from InP Gunn devices with these optimized doping profiles is predicted up to at least 500 GHz and the performance predictions for the two different types of doping profiles are compared

Evaluation of the performance of grade and crossbred ewes

Data from 924 lambs were analyzed by least-squares technique to compare the performance of grade, mixed and crossbred ewes. Birth weight was significantly influenced (P\u3c.01) by sex, type of birth, breeding of lamb and age of dam. Lambs whose breeding involved more breeds were heavier than lambs of grade and mixed breeding. Lambs from ewes over three years of age were heavier than lambs from ewes three years old and younger, Weight of lambs at 120 days was significantly influenced (P\u3c.01) by sex, breed of dam, breeding of lamb, type of birth and rearing and age of dam. Male lambs were heavier than females and lambs born and raised as singles surpassed lambs born as twins, whether raised as singles or as twins. Ewes 4 years old and older produced the heaviest lambs followed by 3-, 2- and 1-year-old dams. Lambs from crossbred ewes were heavier than lambs from grade ewes and ewes of mixed breeding. Analyses of average daily gain, weaning weight and condition score gave results similar to those obtained from the analyses of the other variables studied. Effect of sex on condition score was not significant. From these data it can be concluded that: (l) the performance of crossbred lambs excelled that of grade or mixed breeding (breed composition not precisely known) in all traits studied, (2) lambs from crosses involving more breeds exceeded lambs from crosses involving fewer breeds, and (3) crossbred ewes surpassed ewes of grade and mixed breeding with respect to all traits studied

An evaluation of the utilization of animals exposed to lethal levels of ionizing radiaiton

Animals exhibiting visible signs of radiation sickness could be an important food resource in the event of a nuclear disaster. Market hogs (Sus scrofa domestica) weighing approximately 200-250 lbs were exposed to a total air dose of 700 R at a rate of 1 R or 45 R/min of gamma radiation from a 60°Co source. Bacteriological studies were conducted on pre- and post-irradiation blood specimens. Muscle, liver and mesenteric lymph nodes were cultured for bacteria 10 days post-irradiation when the animals were slaughtered, and muscle samples were cultured again 5 days post-slaughter during which time the carcas-ses had hung in a cooler. Samples of the teres major muscle were taken at the above times for the following chemical analyses: 1) crude protein, 2) soluble protein, 3) ether extract, 4) moisture content and 5) pH. Cooked loins from carcasses of irradiated and control animals were subjected to sensory panel evaluations. A bacteremic state was not detected in the 1 R/min group nor was there a greater incidence of bacterial isolates from the carcasses of irradiated animals as compared to those from the control animals. Staphylococcus aureus was one of several organisms recovered from the meat. Since several strains are capable of producing an enterotoxin, the safety of the meat for consumption is questionable since no tests are available to rapidly identify these strains. The results of deter-mination of chemical properties indicated no significant differences in ether extract, moisture content, crude protein or soluble protein. The pH of the meat from irradiated animals at slaughter was significantly higher (P \u3c .05) than that of control meat. During the storage phase the pH decreased significantly (P \u3c .01). Taste panel evaluations indicated no drastic flavor differences due to treatment. However, color was significantly affected. All animals exposed to 45 R/min developed a bacteremia at least once during the 10-day post-irradiation period, but this bacteremia was not consistent within the group. Bacterial isolates from the muscles of irradiated animals at slaughter and 5 days later were consistently higher than isolates from controls. These bacteria represented an increased number of genera. Because of the possibility of non-specific and staphylococcal food poisoning, it is recommended that this meat not be consumed. Muscle from irradiated animals yielded significantly more ether extract at slaughter (P \u3c .05) and after 5 days storage, while moisture content was significantly lower (P \u3c .05) at both times. A significant reduction (P \u3c .01) in soluble protein was noted during the storage phase. Muscle from irradiated animals again yielded significantly higher pH values (P \u3c .05), but no difference was noted after the storage phase. Taste panel evaluations indicated less treatment effect on both flavor and color than observed in the low dose rate group

On tate duality and a projective scalar property for symmetric algebras

© 2018 Mathematical Sciences Publishers. We identify a class of symmetric algebras over a complete discrete valuation ring O of characteristic zero to which the characterisation of Knörr lattices in terms of stable endomorphism rings in the case of finite group algebras can be extended. This class includes finite group algebras, their blocks and source algebras and Hopf orders. We also show that certain arithmetic properties of finite group representations extend to this class of algebras. Our results are based on an explicit description of Tate duality for lattices over symmetric O-algebras whose extension to the quotient field of O is separable

Endobronchial myxoma: Case report

INTRODUCTION: Pulmonary myxoma is an extremely rare benign neoplasm. It is mostly parenchymal but may occasionally occur within the tracheobronchial tree. There are very few reports of endobronchial myxoma. CASE REPORT: We describe a case of endobronchial myxoma in a 40-year-old female patient with a history of asthma and repeated right-sided pneumonia. Thoracic computed tomography (CT) showed medium lobe atelectasis. Fiber optic bronchoscopy revealed a polypoid, well-circumscribed tumor, causing total obstruction of the medium lobe bronchus. Biopsy of the mass was non-diagnostic. Further study included a positron emission tomography (PET) which demonstrated low metabolic activity of the tumor and no evidence of neoplasia in other location. The patient was submitted to a medium lobectomy and microscopic examination of the tumor revealed myxoid stroma with lobulated pattern, elongated and stellate cells, compatible with myxoma. CONCLUSION: Pulmonary myxoma is extraordinary rare and endobronchial location is very few reported in medical literature

An investigation of South Pole HOx chemistry: Comparison of model results with ISCAT observations

Unexpected high levels of OH and NO were recorded at the South Pole (SP) Atmospheric Research Observatory during the 1998-99 ISCAT field study. Model simulations suggest a major photochemical linkage between observed OH and NO. A detailed comparison of the observations with model predictions revealed good agreement for OH at NO levels between 120 and 380 pptv. However, the model tended to overestimate OH for NO levels < 120 pptv, while it underestimated OH at levels > 380 pptv. The reasons for these deviations appear not to involve NO directly but rather HOx radical scavenging for the low NO conditions and additional HOx sources for the high NO conditions. Because of the elevated levels of NO and highly activated HOx photochemistry, the SP was found to be a strong net source of surface ozone. It is quite likely that the strong oxidizing environment found at the South Pole extends over the entire polar plateau