5,219 research outputs found
Transverse Mode Electron Beam Microwave Generator
An electron beam microwave device having an evacuated interaction chamber to which are coupled a resonant cavity which has an opening between the resonant cavity and the evacuated interaction chamber and an electron gun which causes a narrow beam of electrons to traverse the evacuated interaction chamber. The device also contains a mechanism for feeding back a microwave electromagnetic field from the resonant cavity to the evacuated interaction chamber in such a way as to modulate the direction of propagation of the electron beam, thereby further amplifyjng the microwave electromagnetic field. Furthermore, provision is made for coupling the electromagnetic field out of the electron beam microwave device
Phenomenological model for predicting the energy resolution of neutron-damaged coaxial HPGe detectors
The peak energy resolution of germanium detectors deteriorates with
increasing neutron fluence. This is due to hole capture at neutron-created
defects in the crystal which prevents the full energy of the gamma-ray from
being recorded by the detector. A phenomenological model of coaxial HPGe
detectors is developed that relies on a single, dimensionless parameter that is
related to the probability for immediate trapping of a mobile hole in the
damaged crystal. As this trap parameter is independent of detector dimensions
and type, the model is useful for predicting energy resolution as a function of
neutron fluence.Comment: 7 pages, 7 figure
Fourth Symposium on Chemical Evolution and the Origin and Evolution of Life
This symposium was held at the NASA Ames Research Center, Moffett Field, California, July 24-27, 1990. The NASA exobiology investigators reported their recent research findings. Scientific papers were presented in the following areas: cosmic evolution of biogenic compounds, prebiotic evolution (planetary and molecular), early evolution of life (biological and geochemical), evolution of advanced life, solar system exploration, and the Search for Extraterrestrial Intelligence (SETI)
Bluegrass Land and Life: Land Character, Plants, and Animals of the Inner Bluegrass Region of Kentucky: Past, Present, and Future
The Inner Bluegrass Region of Kentucky is a shining jewel of geography—synonymous in the minds of many with the state of Kentucky. It is unique in many respects: the character of its land, its native vegetation, and its indigenous animal life. The way of life developed by its human inhabitants over the past two hundred years, especially its focus on the Thoroughbred horse, is also unique. The interaction of these two forces—natural and human—is the focus for this important work.
The book includes color plates of representative plant and animal species and typical habitats. The annotated lists of 474 animal and nearly 1,200 plant species describe habitat, frequency, and distribution.
Bluegrass Land and Life is a book that will delight all who share an interest in the Bluegrass region\u27s past and present and a concern for its future.
Mary E. Wharton is retired chairman of biological and earth sciences at Georgetown College. Roger W. Barbour is retired professor of zoology at the University of Kentucky. They are widely known as co-authors of A Guide to the Wildflowers and Ferns of Kentucky.https://uknowledge.uky.edu/upk_biology/1000/thumbnail.jp
Recommended from our members
Analogical Transfer Through Comprehension and Priming
An unexplored means by which analogical transfer might take place is through indirect priming through the interaction of text comprehension and memory retrieval processes. Remind is a structured spreading-activation model of language understanding and reminding in which simple transfer can result from indirect priming from previously processed source analogs. This paper describes two experiments based on Remind's priming-based transfer framework. In Experiment 1, subjects (1) summarized analogous source stories' common plot; (2) rated the comprehensibility of targets related to sources by similar themes, contexts, or themes and contexts; then (3) described any sources incidentally recalled during target rating. Source/target similarity influenced comprehensibility and reminding without any explicit mapping or problem-solving. In Experiment 2, subjects (1) rated each story's comprehensibility in source/target pairs having similar relationships to each other as in Experiment 1; then (2) rated source/target similarity. Analogous targets were rated as more comprehensible than non-analogous targets. Both experiments imply that transfer can be caused by activation of abstract knowledge representations without explicit mapping
Diversity and Abundance of Hymenopterous Parasitoids Associated with Anastrepha fraterculus (Diptera: Tephritidae) in Native and Exotic Host Plants in Misiones, Northeastern Argentina
Some Major host species used by the tephritid fruit flies Anastrepha
fraterculus (Wiede-mann) and Ceratitis capitata (Wiedemann), including
Acca sellowiana (O. Berg) Burret, Campomanesia xanthocarpa O. Berg,
Psidium guajava L., Prunus persica (L.) Batsch, Eriobotrya japonica (Thunb.) Lindl., Citrus reticulata Blanco var. Murcott, C. aurantium L., C. paradisi
Macfadyen var. Dalan Dan, and C. paradisi var. Sudashi, were sampled for fruit fly
larvae between Feb and Dec 2000 in the northernmost section of the Paranaense forest, in the Province of Misiones, NE Argentina. Both A. fraterculus and C. capitata were obtained from these host plant species, with A. fraterculus accounting for 93% of all tephritid puparia identified. Ten species of larval-pupal parasitoids were recovered from A. fraterculus; Doryctobracon areolatus (Szépligeti), D. brasiliensis (Szépligeti), Utetes anastrephae (Viereck), Opius bellus (Gahan), Diachasmimorpha longicaudata (Ashmead) (Opiinae, raconidae),
Odontosema anastrephae Borgmeier, Lopheucoila anastrephae (Rohwer),
Aganaspis pelleranoi (Brèthes) (Eucoilinae, Figitidae), Asobara anastrephae
(Muessebeck) (Alyssinae, Braconidae), and Aceratoneuromyia indica
(Silvestri) (Tetrastichinae, Eulophidae). All these parasitoids, with the exception of D. longicaudata and A. indica, are native to the Neotropical region. No parasitoids were recovered from C. capitata puparia. Asobara anastrephae
and O. anastrephae are newly recorded in Argentina, whereas D. brasiliensis,
U. anastrephae, and L. anastrephae are newly reported in Misiones. The eucoiline
A. pelleranoi wasthe most abundant parasitoid species. Acca sellowiana and P.
guajava harbored the highest parasitoid abundance and diversity.Fil: Schliserman, Pablo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro de Investigaciones y Transferencia de Catamarca. Universidad Nacional de Catamarca. Centro de Investigaciones y Transferencia de Catamarca; ArgentinaFil: Ovruski Alderete, Sergio Marcelo. Consejo Nacional de Investigaciones CientÃficas y Técnicas. Centro CientÃfico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Decoll, Olga. Instituto Nacional de TecnologÃa Agropecuaria. Centro Regional Misiones; ArgentinaFil: Wharton, Robert. Texas A&M University; Estados Unido
Mutations in CHMP2B in lower motor neuron predominant amyotrophic lateral sclerosis (ALS)
Background: Amyotrophic lateral sclerosis (ALS), a common late-onset neurodegenerative disease, is associated with fronto-temporal dementia (FTD) in 3-10% of patients. A mutation in CHMP2B was recently identified in a Danish pedigree with autosomal dominant FTD. Subsequently, two unrelated patients with familial ALS, one of whom also showed features of FTD, were shown to carry missense mutations in CHMP2B. The initial aim of this study was to determine whether mutations in CHMP2B contribute more broadly to ALS pathogenesis.
Methodology/Principal Findings: Sequencing of CHMP2B in 433 ALS cases from the North of England identified 4 cases carrying 3 missense mutations, including one novel mutation, p. Thr104Asn, none of which were present in 500 neurologically normal controls. Analysis of clinical and neuropathological data of these 4 cases showed a phenotype consistent with the lower motor neuron predominant (progressive muscular atrophy (PMA)) variant of ALS. Only one had a recognised family history of ALS and none had clinically apparent dementia. Microarray analysis of motor neurons from CHMP2B cases, compared to controls, showed a distinct gene expression signature with significant differential expression predicting disassembly of cell structure; increased calcium concentration in the ER lumen; decrease in the availability of ATP; down-regulation of the classical and p38 MAPK signalling pathways, reduction in autophagy initiation and a global repression of translation. Transfection of mutant CHMP2B into HEK-293 and COS-7 cells resulted in the formation of large cytoplasmic vacuoles, aberrant lysosomal localisation demonstrated by CD63 staining and impairment of autophagy indicated by increased levels of LC3-II protein. These changes were absent in control cells transfected with wild-type CHMP2B.
Conclusions/Significance: We conclude that in a population drawn from North of England pathogenic CHMP2B mutations are found in approximately 1% of cases of ALS and 10% of those with lower motor neuron predominant ALS. We provide a body of evidence indicating the likely pathogenicity of the reported gene alterations. However, absolute confirmation of pathogenicity requires further evidence, including documentation of familial transmission in ALS pedigrees which might be most fruitfully explored in cases with a LMN predominant phenotype
the Bad, and the Ugly: Using Experiential Learning in the Classroom Page 68
Abstract Academic experiences designed to promote active learning can be thrilling and memorable educational opportunities for students and their instructors. Unfortunately, they can also be miserable failures for students lacking necessary skills and motivation, and for instructors lacking necessary resources and support. This paper describes two active learning projects, both successful in many ways, and draws from them observations and lessons on the failings of active education for some students, and the burdens placed on instructors
Edmonton Obesity Staging System Prevalence and Association with Weight Loss in a Publicly Funded Referral-Based Obesity Clinic
Objectives. To determine the distribution of EOSS stages and differences in weight loss achieved according to EOSS stage, in patients attending a referral-based publically funded multisite weight management clinic. Subjects/Methods. 5,787 obese patients were categorized using EOSS staging using metabolic risk factors, medication use, and severity of doctor diagnosis of obesity-related physiological, functional, and psychological comorbidities from electronic patient files. Results. The prevalence of EOSS stages 0 (no risk factors or comorbidities), 1 (mild conditions), 2 (moderate conditions), and 3 (severe conditions) was 1.7%, 10.4%, 84.0%, and 3.9%, respectively. Prehypertension (63%), hypertension (76%), and knee replacement (33%) were the most common obesity-related comorbidities for stages 1, 2, and 3, respectively. In the models including age, sex, initial BMI, EOSS stage, and treatment time, lower EOSS stage and longer treatment times were independently associated with greater absolute (kg) and percentage of weight loss relative to initial body weight P<0.05. Conclusions. Patients attending this publicly funded, referral-based weight management clinic were more likely to be classified in the higher stages of EOSS. Patients in higher EOSS stages required longer treatment times to achieve similar weight outcomes as those in lower EOSS stages
- …