2,684 research outputs found
Deconstructing Web Browsers Using SoonKra
Many software engineers would agree that, had it not been for virtual machines, the analysis of public-private key pairs might never have occurred. In fact, few cryptographers would disagree with the understanding of voice-over-IP. We introduce a novel application for the understanding of SMPs, which we call SoonKra
Characterization of Alkali Metal Dispensers and Non-Evaporable Getter Pumps in Ultra-High Vacuum Systems for Cold Atomic Sensors
A glass ultrahigh vacuum chamber with rubidium alkali metal dispensers and
non-evaporable getter pumps has been developed and used to create a cold atomic
sample in a chamber that operates with only passive vacuum pumps. The ion-mass
spectrum of evaporated gases from the alkali metal dispenser has been recorded
as a function of dispenser current. The efficacy of the non-evaporable getter
pumps in promoting and maintaining vacuum has been characterized by observation
of the Rb vapor optical absorption on the D2 transition at 780 nm and vacuum
chamber pressure rate of rise tests. We have demonstrated a sample of
laser-cooled Rb atoms in this chamber when isolated and operating without
active vacuum pumps
Advanced propfan analysis for the family of commuter airplanes
Advanced propfans were selected to be used throughout the family of commuters. These propulsion systems offer a 25 to 28 percent fuel savings over comparably sized turbofans operating in the 1990s. A brief study of the propulsion systems available for the family of commuters is provided and the selection of the advanced turboprops justified. The propeller and engine designs and performance are discussed. The integration of these designs are examined. Also addressed is the noise considerations and constraints due to propfan installation
Conversations With Long-Time Adult Educators
The purpose of this study was to collect and analyze information from long-time adult educators, to learn from their experiences, and to ensure the wisdom they have gained throughout their time spent in the field is not lost
Feeding Habits of Common Snook, Centropomus undecimalis, in Charlotte Harbor, Florida
We examined the feeding habits, ontogenetic and seasonal diet variations, and predator size–prey size relationships of common snook, Centropomus undecimalis, in Charlotte Harbor, Florida, through stomach contents analysis. A total of 694 stomachs were extracted from common snook (300–882 mm standard length [SL]) during a 24-month period (March 2000–February 2002); 432 stomachs contained prey items. At least 37 prey taxa were identified, including 19 that had not been previously reported. Fishes made up 71% of the prey by number and 90% by weight. Three prey items made up almost 50% of the diet numerically—Lagodon rhomboides, Anchoa spp., and Farfantepenaeus duorarum. Seven species made up more than 60% of the diet by weight—L. rhomboides, Cynoscion nebulosus, Mugil gyrans, Bairdiella chrysoura, Synodus foetens, Orthopristis chrysoptera, and Mugil cephalus. An ontogenetic shift in prey preference was identified in adult common snook at around 550 mm SL. Smaller individuals (300–549 mm SL) ate more F. duorarum, palaemonid shrimp, cyprinodontids, and Eucinostomus spp. than did larger individuals (550–882 mm SL), which ate more S. foetens, ariids, and sciaenids. Significant, positive relationships between predator size and prey size were observed between common snook and L. rhomboides, O. chrysoptera, portunid crabs, and all fish prey combined. Prey size selection contributed to some seasonal differences in their diet. For example, in winter when L. rhomboides are abundant in the estuary and small in size (mean = 23 mm SL), common snook ate few individuals, but they consumed many during summer when larger L. rhomboides (mean = 51 mm SL) were available. In summary, common snook are opportunistic predators that feed on a wide variety of prey and exploit specific-sized prey that are abundant in their environment
Primary Upper Urinary Tract Small Cell Carcinoma: A Case Series and Literature Review
Background: Primary upper urinary tract small cell carcinoma (SCC) is exceedingly rare with \u3c 30 cases reported in the literature. Little is known about the incidence, diagnosis, treatment, and outcomes in these patients. We present a series of three patients with primary upper tract SCC.
Case Presentation: Patient 1 is an 89-year-old Caucasian male who presented with hydroureteronephrosis and a mass in the proximal right ureter. Biopsy revealed SCC. Without further intervention, the patient died 2 months after his diagnosis. Patient 2 is a 67-year-old Caucasian female who underwent left laparoscopic nephroureterectomy for primary distal ureteral SCC, pT4N1M0. She developed lymphadenopathy and completed external beam radiation to the pelvis and four courses of cisplatin-based chemotherapy. She died from metastatic disease 7 months after diagnosis. Patient 3 is a 45-year-old female who underwent open right radical nephrectomy, retroperitoneal lymph node dissection, and hepatic metastasectomy for metastatic primary upper tract SCC, pT3N1M1. She underwent two subsequent retroperitoneal debulking procedures for recurrence followed by treatment with octreotide. She developed widespread metastasis and was treated with temozolomide and capecitabine before her death 80 months after diagnosis.
Conclusion: This series contributes to the limited knowledge of the management and natural course of primary upper tract SCC. Patient 1 represents the first disease-specific mortality reported in a patient who received no therapy. Patient 3 represents the longest reported survival with metastatic disease, and the first treated with octreotide. The patient was managed with aggressive repeat surgical resection and exhibited 2 years of progression-free survival on octreotide. Emphasis should be placed on aggressive resection of all visible disease combined with the use of multimodal adjuvant chemoradiation for selected patients in this rare disease
Updated repeat orbit interferometry package released
RO1_PAC V2.3, a Repeat Orbit Interferometry package that allows topographic and surface change researchers to apply Interferometric Synthetic Aperture Radar (InSAR) methods, is now freely available to the community InSAR is the synthesis of conventional SAR and interferometry techniques that have been developed over several decades in radio astronomy and radar remote sensing. In recent years, it has opened entirely new application areas for radar in the Earth system sciences, including topographic mapping and geodesy.
RO1_PAC, developed primarily to work with European Remote Sensing (ERS) satellite radar data, currently supports ERS-1, ERS-2, and Japanese Earth Resources Satellite (JERS) radar data, and is configurable to work with “strip-mode” data from all existing satellite radar instruments. The first release of RO1_ PAC (V1.0) was made quietly in 2000, and roughly 30 groups in the academic and research community currently use it
Towards real-time classification of astronomical transients
Exploration of time domain is now a vibrant area of research in astronomy, driven by the advent of digital synoptic sky surveys. While panoramic surveys can detect variable or transient events, typically some follow-up observations are needed; for short-lived phenomena, a rapid response is essential. Ability to automatically classify and prioritize transient events for follow-up studies becomes critical as the data rates increase. We have been developing such methods using the data streams from the Palomar-Quest survey, the Catalina Sky Survey and others, using the VOEventNet framework. The goal is to automatically classify transient events, using the new measurements, combined with archival data (previous and multi-wavelength measurements), and contextual information (e.g., Galactic or ecliptic latitude, presence of a possible host galaxy nearby, etc.); and to iterate them dynamically as the follow-up data come in (e.g., light curves or colors). We have been investigating Bayesian methodologies for classification, as well as discriminated follow-up to optimize the use of available resources, including Naive Bayesian approach, and the non-parametric Gaussian process regression. We will also be deploying variants of the traditional machine learning techniques such as Neural Nets and Support Vector Machines on datasets of reliably classified transients as they build up
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Agricultural Waste Remediation and H2 Production by Hyperthermophilic Heterotrophs: Bioinformatics, Taxonomy, and Physiology
In the United States, nearly 35 million tons of food waste are delivered to landfills and wastewater treatment plants for disposal each year. This places a burden on landfills and the environment through the introduction of foreign chemicals. Utilizing hyperthermophilic heterotrophs for waste treatment in a consolidated bioprocess could potentially remediate these organics, increase reaction rates, kill pathogens, produce a bioenergy product (H2), and lower costs relative to mesophilic waste treatment options. However, it is unknown how various agricultural waste streams will affect hyperthermophilic growth and metabolite production. We investigated Thermococcales species for this purpose. Specifically, we chose Pyrococcus furiosus and Thermococcus paralvinellae because of their use as a model organism and their potential H2 production, respectively. In this set of studies, we determined 1) the genomic sequence of T. paralvinellae, 2) how representative these two microorganisms are of Thermococcales species, and 3) the physiology of both organisms when grown in different defined and waste-mediated environmental conditions. We found that T. paralvinellae is genomically most similar to T. barophilus and that P. furiosus and T. paralvinellae are good representatives of different potential metabolisms of the Thermococcales. Both P. furiosus and T. paralvinellae are amenable to the catabolism of carbohydrates and peptides with H2 production over a range of pH and acetate concentrations with little impact on growth and H2 production rates. The mechanisms that P. furiosus and T. paralvinellae are using for redox balance may not be the same, as seen by the differential expression of a number of enzymatic activities. T. paralvinellae consistently produced more H2 on both raw milk and spent grain wastes. Mesophilic bacteria were eliminated from the wastes in the process of hyperthermophilic growth, indicating that it is feasible to use hyperthermophilic heterotrophs in a single process step to reduce the organic load of food and agricultural wastes, generate H2 as an energy byproduct, and remove pathogens
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