277 research outputs found
A Study of the Use of a Local Fly Ash in Concrete Mixes
The widespread use of powdered coal in industrial furnaces has, since its introduction in the 1930\u27s, produced considerable increases in efficiency for many industrial processes. In its wake, however, it has brought its own unique problems, and chief among these has been the problem of collecting and disposing of the residue which results from the combustion of the powdered or ground coal. This residue, known commonly as fly ash, is a nuisance if it is allowed to be dispersed into the atmosphere; and if collected it presents a difficult disposal problem. In present industrial practice it is almost always collected, either with electrostatic precipitators or cyclone separators, and deposited in ever-growing disposal dumps. A recent estimate (20)* gives the imposing figure of six million tons as the annual U.S. production of this waste product
Academic Perspectives on Agribusiness: An International Survey
The IFAMR is published by (IFAMA) the International Food and Agribusiness Management Review. www.ifama.orgpromotion and tenure, agribusiness, teaching, grantsmanship, research, Agribusiness, Institutional and Behavioral Economics, Productivity Analysis, Teaching/Communication/Extension/Profession, Q130,
Dissipation Rate of Turbulent Kinetic Energy in Diel Vertical Migrations: Comparison of ANSYS Fluent Model to Measurements
Recent studies suggest that diel vertical migrations of zooplankton may have an impact on ocean mixing, though details are not completely clear. A strong sound scattering layer of zooplankton undergoing diel vertical migrations was observed in Saanich Inlet, British Colombia, Canada by Kunze et al. (2006). In this study, a shipboard 200- kHz echosounder was used to track vertical motion of the sound scattering layer, and microstructure profiles were collected to observe turbulence. An increase of dissipation rate of turbulent kinetic energy by four to five orders of magnitude was measured during diel vertical migrations of zooplankton in one case (but not observed during other cases). A strong sound scattering layer undergoing diel vertical migration was also observed in the Straits of Florida via a bottom mounted acoustic Doppler current profiler at 244 m isobath. A 3-D non-hydrostatic computational fluid dynamics model with Lagrangian particle injections (a proxy for migrating zooplankton) via a discrete phase model was used to simulate the effect of diel vertical migrations on the turbulence for both Saanich Inlet and the Straits of Florida. The model was initialized with idealized (but based on observation) density and velocity profiles. Particles, with buoyancy adjusted to serve as a proxy for vertically swimming zooplankton, were injected to simulate diel vertical migration cycles. Results of models run with extreme concentrations of particles showed an increase in dissipation rate of turbulent kinetic energy of approximately five orders of magnitude over background turbulence during migration of particles in both Saanich Inlet and the Straits of Florida cases (though direct relation of the turbulence produced by buoyant particles and swimming organisms isn’t straightforward). This increase was quantitatively consistent, with turbulence measurements by Kunze et al. (2006). When 10 times fewer particles were injected into the model, the effect on dissipation rate of turbulent kinetic energy was an order of magnitude smaller than that from the extreme concentration. At a concentration of particles 100 times smaller than the extreme concentration, there was no longer an observable effect. In the Straits of Florida, direct turbulence measurements were not available to make a quantitative comparison. However, a small, but statistically significant decrease in northward current velocity profiles during migration times were observed after averaging these profiles over 11 months. A small decrease of current velocity connected to the vertical migrations of particles was reproduced in the Straits of Florida model case. The deviations in the velocity profiles can be explained by the increase in turbulent mixing during vertical migration periods
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 2: Systematic review of evidence regarding resection extent in generally healthy patients
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options (lobectomy, segmentectomy, wedge, stereotactic body radiotherapy, thermal ablation), weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in generally healthy patients is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons with at least some adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.
Results: In healthy patients there is no short-term benefit to sublobar resection
Conclusions: A systematic, comprehensive summary of evidence regarding resection extent in healthy patients with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation on which to build a framework for individualized clinical decision-making
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 3: Systematic review of evidence regarding surgery in compromised patients or specific tumors
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after lobectomy, segmentectomy and wedge resection in older patients, patients with limited pulmonary reserve and favorable tumors is the focus of this paper. Evidence was abstracted from randomized trials and non-randomized comparisons (NRCs) with adjustment for confounders. The analysis involved careful assessment, including characteristics of patients, settings, residual confounding etc. to expose degrees of uncertainty and applicability to individual patients. Evidence is summarized that provides an at-a-glance overall impression as well as the ability to delve into layers of details of the patients, settings and treatments involved.
Results: In older patients, perioperative mortality is minimally altered by resection extent and only slightly affected by increasing age; sublobar resection may slightly decrease morbidity. Long-term outcomes are worse after lesser resection; the difference is slightly attenuated with increasing age. Reported short-term outcomes are quite acceptable in (selected) patients with severely limited pulmonary reserve, not clearly altered by resection extent but substantially improved by a minimally invasive approach. Quality-of-life (QOL) and impact on pulmonary function hasn\u27t been well studied, but there appears to be little difference by resection extent in older or compromised patients. Patient selection is paramount but not well defined. Ground-glass and screen-detected tumors exhibit favorable long-term outcomes regardless of resection extent; however solid tumors \u3c1 cm are not a reliably favorable group.
Conclusions: A systematic, comprehensive summary of evidence regarding resection extent in compromised patients and favorable tumors with attention to aspects of applicability, uncertainty and effect modifiers provides a foundation for a framework for individualized decision-making
Warm and Dense Molecular Gas in the N159 Region: 12CO J=4-3 and 13CO J=3-2 Observations with NANTEN2 and ASTE
New 12CO J=4-3 and 13CO J=3-2 observations of the N159 region in the Large
Magellanic Cloud have been made. The 12CO J=4-3 distribution is separated into
three clumps. These new measurements toward the three clumps are used in
coupled calculations of molecular rotational excitation and line radiation
transfer, along with other transitions of the 12CO as well as the isotope
transitions of 13CO. The temperatures and densities are determined to be
~70-80K and ~3x10^3 cm-3 in N159W and N159E and ~30K and ~1.6x10^3 cm-3 in
N159S. These results are compared with the star formation activity. The N159E
clump is associated with embedded cluster(s) as observed at 24 micron and the
derived high temperature is explained as due to the heating by these sources.
The N159E clump is likely responsible for a dark lane in a large HII region by
the dust extinction. The N159W clump is associated with embedded clusters
mainly toward the eastern edge of the clump only. These clusters show offsets
of 20"-40" from the 12CO J=4-3 peak and are probably responsible for heating
indicated by the derived high temperature. The N159W clump exhibits no sign of
star formation toward the 12CO J=4-3 peak position and its western region. We
suggest that the N159W peak represents a pre-star-cluster core of ~105M_sol
which deserves further detailed studies. Note that recent star formation took
place between N159W and N159E as indicated by several star clusters and HII
regions, while the natal molecular gas toward the stars have already been
dissipated by the ionization and stellar winds of the OB stars. The N159S clump
shows little sign of star formation as is consistent with the lower temperature
and somewhat lower density. The N159S clump is also a candidate for future star
formation
A guide for managing patients with stage I NSCLC: Deciding between lobectomy, segmentectomy, wedge, SBRT and ablation-part 4: Systematic review of evidence involving SBRT and ablation
Background: Clinical decision-making for patients with stage I lung cancer is complex. It involves multiple options [lobectomy, segmentectomy, wedge, stereotactic body radiotherapy (SBRT), thermal ablation], weighing multiple outcomes (e.g., short-, intermediate-, long-term) and multiple aspects of each (e.g., magnitude of a difference, the degree of confidence in the evidence, and the applicability to the patient and setting at hand). A structure is needed to summarize the relevant evidence for an individual patient and to identify which outcomes have the greatest impact on the decision-making.
Methods: A PubMed systematic review from 2000-2021 of outcomes after SBRT or thermal ablation
Results: Short-term outcomes are meaningfully better after SBRT than resection. SBRT doesn\u27t affect quality-of-life (QOL), on average pulmonary function is not altered, but a minority of patients may experience gradual late toxicity. Adjusted non-randomized comparisons demonstrate a clinically relevant detriment in long-term outcomes after SBRT
Conclusions: A systematic, comprehensive summary of evidence regarding Stereotactic Body Radiotherapy or thermal ablatio
The Murchison Widefield Array: Design Overview
The Murchison Widefield Array (MWA) is a dipole-based aperture array
synthesis telescope designed to operate in the 80-300 MHz frequency range. It
is capable of a wide range of science investigations, but is initially focused
on three key science projects. These are detection and characterization of
3-dimensional brightness temperature fluctuations in the 21cm line of neutral
hydrogen during the Epoch of Reionization (EoR) at redshifts from 6 to 10,
solar imaging and remote sensing of the inner heliosphere via propagation
effects on signals from distant background sources,and high-sensitivity
exploration of the variable radio sky. The array design features 8192
dual-polarization broad-band active dipoles, arranged into 512 tiles comprising
16 dipoles each. The tiles are quasi-randomly distributed over an aperture
1.5km in diameter, with a small number of outliers extending to 3km. All
tile-tile baselines are correlated in custom FPGA-based hardware, yielding a
Nyquist-sampled instantaneous monochromatic uv coverage and unprecedented point
spread function (PSF) quality. The correlated data are calibrated in real time
using novel position-dependent self-calibration algorithms. The array is
located in the Murchison region of outback Western Australia. This region is
characterized by extremely low population density and a superbly radio-quiet
environment,allowing full exploitation of the instrumental capabilities.Comment: 9 pages, 5 figures, 1 table. Accepted for publication in Proceedings
of the IEE
Low-Frequency Observations of the Moon with the Murchison Widefield Array
A new generation of low-frequency radio telescopes is seeking to observe the redshifted 21 cm signal from the epoch of reionization (EoR), requiring innovative methods of calibration and imaging to overcome the difficulties of wide-field low-frequency radio interferometry. Precise calibration will be required to separate the expected small EoR signal from the strong foreground emission at the frequencies of interest between 80 and 300 MHz. The Moon may be useful as a calibration source for detection of the EoR signature, as it should have a smooth and predictable thermal spectrum across the frequency band of interest. Initial observations of the Moon with the Murchison Widefield Array 32 tile prototype show that the Moon does exhibit a similar trend to that expected for a cool thermally emitting body in the observed frequency range, but that the spectrum is corrupted by reflected radio emission from Earth. In particular, there is an abrupt increase in the observed flux density of the Moon within the internationally recognized frequency modulated (FM) radio band. The observations have implications for future low-frequency surveys and EoR detection experiments that will need to take this reflected emission from the Moon into account. The results also allow us to estimate the equivalent isotropic power emitted by the Earth in the FM band and to determine how bright the Earth might appear at meter wavelengths to an observer beyond our own solar system
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