378 research outputs found
Photovoltaic Energy to Face an Earthquake
The application of photovoltaic technology is necessary to reduce the harmful effects of an intense earthquake in the city of Portoviejo. It is based on the information obtained about the occurrence of the earthquake on April 16 and considering data from other events of the same nature occurred in the territory, an assessment of the seismic risk for the city and by characterization of one of the zones is made subject to danger, the introduction of photovoltaic luminaires is proposed in order to provide certain strengths that can facilitate the work of the first urgency in the rescue and urgent repair of breakdowns, as well as the evacuation of the population to safer areas especially at night. An analysis is made of the technological structure of photovoltaic luminaires and the prices they have in the market, both internally and Internationally
Bone metastases in patients with metastatic breast cancer: morphologic and metabolic monitoring of response to systemic therapy with integrated PET/CT
Purpose: to retrospectively compare morphologic and metabolic changes in bone metastases in response to systemic therapy in patients with metastatic breast cancer (MBC) with integrated positron emission tomography (PET)/computed tomography (CT). Materials and methods: the institutional review board waived the requirement for informed consent and approved this HIPAA-compliant study. A retrospective analysis was performed with 102 women (mean age, 55 years) with MBC who received systemic treatment. All patients underwent integrated PET/CT before and after treatment. Two reviewers analyzed the images in consensus. Morphologic changes, including morphologic patterns, and lesion attenuation were evaluated. Standardized uptake value (SUV) and total lesion glycolysis (TLG) were analyzed to evaluate metabolic changes. Uni- and multivariate analyses were performed to identify factors that enabled response duration (RD) to be predicted. Results: at baseline, the morphologic patterns of the target lesions were lytic (n = 33), sclerotic (n = 22), mixed (n = 42), and unclassified (n = 5). Progression of sclerotic change after treatment was identified in 49 patients (48%). After treatment, the mean attenuation of the lesion increased, whereas the mean SUV and TLG decreased. Increases in attenuation correlated significantly with decreases in SUV (r = -0.510, P < .001) and TLG (r = -0.491, P < . 001). Univariate analysis revealed that the increase in attenuation and the decrease in SUV were potential predictors of RD. Multivariate analysis revealed that an increase in the change in SUV was a significant predictor of RD (relative risk, 2.4; P = .003). Conclusion: a decrease in SUV after treatment was an independent predictor of RD in patients with MBC who had bone metastases
Diffuse Ionized Gas in the Dwarf Irregular Galaxy DDO 53
The spectral characteristics throughout the dwarf irregular galaxy DDO 53 are
studied. The results are very similar to those for other irregular galaxies:
high excitation and low values of the [SII]/Halpha ratio. The most likely
ionization source is photon leakage from the classical HII regions, without any
other source, although the interstellar medium of the galaxy is quite
perturbed. Moreover, the physical conditions throughout the galaxy do not
change very much because both the photon leakage percentage and the ionization
temperature are very similar. In addition, the determined metal content for two
HII regions indicates that DDO 53 is a low-metallicity galaxy.Comment: 32 pages, 9 figures, 7 tables. AJ, in pres
Chronic thyroiditis in patients with advanced breast carcinoma: metabolic and morphologic changes on PET-CT
Purpose: to investigate clinical implications of FDG uptake in the thyroid glands in patients with advanced breast carcinoma by comparing metabolic and morphologic patterns on positron emission tomography (PET)/computed tomography (CT). Methods: the institutional review board waived the requirement for informed consent. A retrospective analysis was performed in 146 women (mean age 54 years) with advanced breast carcinoma who received systemic treatment. All patients underwent PET-CT before and after treatment. All PET-CT studies were reviewed in consensus by two reviewers. Morphologic changes including volume and mean parenchymal density of the thyroid glands were evaluated. Maximum standardized uptake value (SUVmax) and total lesion glycolysis (TLG) were determined to evaluate metabolic changes. These parameters were compared between patients with chronic thyroiditis who received thyroid hormone replacement therapy and those who did not. Results: of the 146 patients, 29 (20%) showed bilaterally diffuse uptake in the thyroid glands on the baseline PET-CT scan. The SUVmax showed a linear relationship with volume (r = 0.428, p = 0.021) and the mean parenchymal density (r = -0.385, p = 0.039) of the thyroid glands. In 21 of the 29 patients (72%) with hypothyroidism who received thyroid hormone replacement therapy, the volume, mean parenchymal density, SUVmax, and TLG of the thyroid glands showed no significant changes. In contrast, 8 of the 29 patients (28%) who did not receive thyroid hormone replacement therapy showed marked decreases in SUVmax and TLG. Conclusion: diffuse thyroid uptake on PET-CT represents active inflammation caused by chronic thyroiditis in patients with advanced breast carcinoma. Diffuse thyroid uptake may also address the concern about subclinical hypothyroidism which develops into overt disease during follow-up
The Future of Micro-grids in Ecuador
An analysis is made on the development of power lines worldwide and that offer the approaches of the impacts that are generated in the economic and environmental, which justify the application of smart grids in Ecuador, as an effective way to raise the efficiency of the electric power service and to achieve a more efficient use of the energy that is generated by showing the different technologies used in electricity generation where renewable energy sources are incorporated. A comparative analysis of how the installed generation power has been increasing until 2016 is shown
The Subarcsecond Mid-Infrared View of Local Active Galactic Nuclei. IV. The L- and M-band Imaging Atlas
We present the largest currently existing subarcsecond 3-5 m atlas of
119 local () active galactic nuclei (AGN). This atlas includes AGN of
5 subtypes: 22 are Seyfert 1; 5 are intermediate Seyferts; 46 are Seyfert 2; 26
are LINERs; and 20 are composites/starbursts. Each AGN was observed with VLT
ISAAC in the - and/or -bands between 2000 and 2013. We detect at
3 confidence 92 sources in the -band and 83 sources in the -band.
We separate the flux into unresolved nuclear flux and resolved flux through
two-Gaussian fitting. We report the nuclear flux, extended flux, apparent size,
and position angle of each source, giving upper-limits for sources
which are undetected. Using WISE W1- and W2-band photometry we derive relations
predicting the nuclear and fluxes for Sy1 and Sy2 AGN based on their
W1-W2 color and WISE fluxes. Lastly, we compare the measured mid-infrared
colors to those predicted by dusty torus models SKIRTOR, CLUMPY, CAT3D, and
CAT3D-WIND, finding best agreement with the latter. We find that models
including polar winds best reproduce the 3-5m colors, indicating that
winds are an important component of dusty torus models. We find that several
AGN are bluer than models predict. We discuss several explanations for this and
find that it is most plausibly stellar light contamination within the ISAAC
-band nuclear fluxes.Comment: Main Text: 22 pages, 9 figures, 3 tables. Accepted by Ap
The dusty heart of Circinus II. Scrutinizing the LM-band dust morphology using MATISSE
In this paper we present the first-ever - and -band interferometric
observations of Circinus, building upon a recent -band analysis. We used
these observations to reconstruct images and fit Gaussian models to the and
bands. Our findings reveal a thin edge-on disk whose width is marginally
resolved and is the spectral continuation of the disk imaged in the band to
shorter wavelengths. Additionally, we find a point-like source in the and
bands that, based on the -band spectral energy distribution fit,
corresponds to the -band point source. We also demonstrate that there is no
trace of direct sightlines to hot dust surfaces in the circumnuclear dust
structure of Circinus. By assuming the dust is present, we find that
obscuration of A mag is necessary to reproduce the
measured fluxes. Hence, the imaged disk could play the role of the obscuring
"torus" in the unified scheme of active galactic nuclei. Furthermore, we
explored the parameter space of the disk + hyperbolic cone radiative transfer
models and identify a simple modification at the base of the cone. Adding a
cluster of clumps just above the disk and inside the base of the hyperbolic
cone provides a much better match to the observed temperature distribution in
the central aperture. This aligns well with the radiation-driven fountain
models that have recently emerged. Only the unique combination of sensitivity
and spatial resolution of the VLTI allows such models to be scrutinized and
constrained in detail. We plan to test the applicability of this detailed dust
structure to other MATISSE-observed active galactic nuclei in the future.Comment: Main article: 12 pages, 6 figures. Accepted for publication in A&A.
arXiv admin note: text overlap with arXiv:2205.0157
Constraining the Ratio in TeV Cosmic Rays with Observations of the Moon Shadow by HAWC
An indirect measurement of the antiproton flux in cosmic rays is possible as
the particles undergo deflection by the geomagnetic field. This effect can be
measured by studying the deficit in the flux, or shadow, created by the Moon as
it absorbs cosmic rays that are headed towards the Earth. The shadow is
displaced from the actual position of the Moon due to geomagnetic deflection,
which is a function of the energy and charge of the cosmic rays. The
displacement provides a natural tool for momentum/charge discrimination that
can be used to study the composition of cosmic rays. Using 33 months of data
comprising more than 80 billion cosmic rays measured by the High Altitude Water
Cherenkov (HAWC) observatory, we have analyzed the Moon shadow to search for
TeV antiprotons in cosmic rays. We present our first upper limits on the
fraction, which in the absence of any direct measurements, provide
the tightest available constraints of on the antiproton fraction for
energies between 1 and 10 TeV.Comment: 10 pages, 5 figures. Accepted by Physical Review
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