8,479 research outputs found
Space Station Freedom delta pressure leakage rate comparison test data analysis report
Results are provided of a series of tests performed to identify the relationship between gas leakage rates across a seal at various internal to external pressure ratios. The results complement and provide insight into the analysis technique used to obtain the results presented in MSFC SSF/DEV/EL91-008, 'Space Station Freedom (S.S. Freedom) Seal Flaw Study with Delta Pressure Leak Rate Comparison Test Report.
Different quantization mechanisms in single-electron pumps driven by surface acoustic waves
We have studied the acoustoelectric current in single-electron pumps driven
by surface acoustic waves. We have found that in certain parameter ranges two
different sets of quantized steps dominate the acoustoelectric current versus
gate-voltage characteristics. In some cases, both types of quantized steps
appear simultaneously though at different current values, as if they were
superposed on each other. This could indicate two independent quantization
mechanisms for the acoustoelectric current.Comment: 6 pages, 3 figure
Information transfer through a one-atom micromaser
We consider a realistic model for the one-atom micromaser consisting of a
cavity maintained in a steady state by the streaming of two-level Rydberg atoms
passing one at a time through it. We show that it is possible to monitor the
robust entanglement generated between two successive experimental atoms passing
through the cavity by the control decoherence parameters. We calculate the
entanglement of formation of the joint two-atom state as a function of the
micromaser pump parameter. We find that this is in direct correspondence with
the difference of the Shannon entropy of the cavity photons before and after
the passage of the atoms for a reasonable range of dissipation parameters. It
is thus possible to demonstrate information transfer between the cavity and the
atoms through this set-up.Comment: Revtex, 5 pages, 2 encapsulated ps figures; added discussion on
information transfer in relation with cavity photon statistics; typos
corrected; Accepted for Publicaiton in Europhysics Letter
Metastatic pattern in adenocarcinoma of the lung An autopsy study from a cohort of 137 consecutive patients with complete resection
A cohort of 137 patients with completely resected stage I or II adenocarcinoma of the lung was observed from the time of operation; the metastatic pattern determined at autopsy is described in relation to clinical, histologic, and laboratory variables. The pretreatment variables evaluated were performance status, age, gender, lactate dehydrogenase, stage, degree of differentiation, and histologic subtype of adenocarcinoma of the lung. Patients who survived longer than 30 days after operation were eligible for analysis, and 35 autopsies were performed in this patient group (autopsy rate: 39.8%). The most common intrathoracic metastatic sites were mediastinal lymph nodes (43%), lung (31%), pleura (20%), pericardium (9%), and heart (6%). The most common extrathoracic sites were liver (37%), brain (33%), bones (21%), adrenals (17%), and kidneys (17%). Patients undergoing resection for stage I disease had significantly fewer intrathoracic metastases than patients with stage II disease (p = 0.01). Patients who survived less than 1 year had significantly more extrathoracic metastases than patients who survived for a longer period (p = 0.01). Patients with highly differentiated tumors had fewer extrathoracic metastases than patients with less differentiated tumors. No other statistically significant differences were observed. Overall, patients with stage I adenocarcinoma of the lung had better local control of the disease at autopsy than those with stage 11 disease, but distant metastases are a large problem despite the favorable prognosis of this patient group. The extrathoracic metastatic potential was greatest for less differentiated tumors. An active adjuvant systemic therapy after resection is needed in selected patients with poorly differentiated adenocarcinomas of the lung, even in those with stage I disease
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