Evidence of Wave Damping at Low Heights in a Polar Coronal Hole

We have measured the widths of spectral lines from a polar coronal hole using the Extreme Ultraviolet Imaging Spectrometer onboard Hinode. Polar coronal holes are regions of open magnetic field and the source of the fast solar wind. We find that the line widths decrease at relatively low heights. Previous observations have attributed such decreases to systematic effects, but we find that such effects are too small to explain our results. We conclude that the line narrowing is real. The non-thermal line widths are believed to be proportional to the amplitude of Alfven waves propagating along these open field lines. Our results suggest that Alfven waves are damped at unexpectedly low heights in a polar coronal hole. We derive an estimate on the upper limit for the energy dissipated between 1.1 and 1.3 solar radii and find that it is enough to account for up to 70% of that required to heat the polar coronal hole and accelerate the solar wind.Comment: Accepted for publication in the Astrophysical Journal, April 201

Collisional quantum thermometry

We introduce a general framework for thermometry based on collisional models, where ancillas probe the temperature of the environment through an intermediary system. This allows for the generation of correlated ancillas even if they are initially independent. Using tools from parameter estimation theory, we show through a minimal qubit model that individual ancillas can already outperform the thermal Cramer-Rao bound. In addition, due to the steady-state nature of our model, when measured collectively the ancillas always exhibit superlinear scalings of the Fisher information. This means that even collective measurements on pairs of ancillas will already lead to an advantage. As we find in our qubit model, such a feature may be particularly valuable for weak system-ancilla interactions. Our approach sets forth the notion of metrology in a sequential interactions setting, and may inspire further advances in quantum thermometry

Differential Emission Measure Analysis of a Polar Coronal Hole During the Solar Minimum in 2007

We have performed a differential emission measure (DEM) analysis for a polar coronal hole observed during solar minimum in 2007. Five observations are analyzed spanning the coronal hole from the central meridian to the boundary with the quiet-Sun corona. The observed heights ranged from 1.05 to 1.20 R ☉. The analysis shows that the plasma is not strictly isothermal anywhere, but rather has a high-temperature component that extends up to log T(K) = 6.2-6.3. The size and importance of this component depend on location, and its evolving magnitude with height marks the boundary between the coronal hole and the quiet corona, where it becomes dominant. The DEM of the coronal hole plasma below log T(K) = 6.0 decreases faster with height than that of the high-temperature component. We discuss the possible nature of the high-temperature component. Our results highlight the potential limitations of isothermal analyses. Such methods actually measure a DEM-weighted average temperature and as a result can infer artificial temperature gradients. Assuming the gas is isothermal along the line of sight can also yield incorrect electron densities. By revealing structures along the line of sight, a DEM analysis can also be used to more reliably interpret electron temperature and density measurements

A New Approach To Analyzing Solar Coronal Spectra And Updated Collisional Ionization Equilibrium Calculations. II. Updated Ionization Rate Coefficients

We have re-analyzed Solar Ultraviolet Measurement of Emitted Radiation (SUMER) observations of a parcel of coronal gas using new collisional ionization equilibrium (CIE) calculations. These improved CIE fractional abundances were calculated using state-of-the-art electron-ion recombination data for K-shell, L-shell, Na-like, and Mg-like ions of all elements from H through Zn and, additionally, Al- through Ar-like ions of Fe. They also incorporate the latest recommended electron impact ionization data for all ions of H through Zn. Improved CIE calculations based on these recombination and ionization data are presented here. We have also developed a new systematic method for determining the average emission measure (EM) and electron temperature (Te ) of an isothermal plasma. With our new CIE data and a new approach for determining average EM and Te , we have re-analyzed SUMER observations of the solar corona. We have compared our results with those of previous studies and found some significant differences for the derived EM and Te . We have also calculated the enhancement of coronal elemental abundances compared to their photospheric abundances, using the SUMER observations themselves to determine the abundance enhancement factor for each of the emitting elements. Our observationally derived first ionization potential factors are in reasonable agreement with the theoretical model of Laming

Evidence of Wave Damping at Low Heights in a Polar Coronal Hole

We have measured the widths of spectral lines from a polar coronal hole using the Extreme Ultraviolet Imaging Spectrometer on board Hinode. Polar coronal holes are regions of open magnetic field and the source of the fast solar wind. We find that the line widths decrease at relatively low heights. Previous observations have attributed such decreases to systematic effects, but we find that such effects are too small to explain our results. We conclude that the line narrowing is real. The non-thermal line widths are believed to be proportional to the amplitude of Alfvén waves propagating along these open field lines. Our results suggest that Alfvén waves are damped at unexpectedly low heights in a polar coronal hole. We derive an estimate on the upper limit for the energy dissipated between 1.1 R ☉ and 1.3 R ☉ and find that it is enough to account for up to 70% of that required to heat the polar coronal hole and accelerate the solar wind

Properties of a Polar Coronal Hole During the Solar Minimum in 2007

We report measurements of a polar coronal hole during the recent solar minimum using the Extreme Ultraviolet Imaging Spectrometer on Hinode. Five observations are analyzed that span the polar coronal hole from the central meridian to the boundary with the quiet-Sun corona. We study the observations above the solar limb in the height range of 1.03-1.20 R ☉. The electron temperature T e and emission measure (EM) are found using a geometric mean emission measure method. The EM derived from the elements Fe, Si, S, and Al are compared in order to measure relative coronal-to-photospheric abundance enhancement factors. We also studied the ion temperature T i and the non-thermal velocity v nt using the line profiles. All these measurements are compared to polar coronal hole observations from the previous (1996-1997) solar minimum and to model predictions for relative abundances. There are many similarities in the physical properties of the polar coronal holes between the two minima at these low heights. We find that the electron density, T e, and T i are comparable in both minima. T e shows a comparable gradient with height. Both minima show a decreasing T i with increasing charge-to-mass ratio q/M. A previously observed upturn of T i for ions above q/M>0.25 was not found here. We also compared relative coronal-to-photospheric elemental abundance enhancement factors for a number of elements. These ratios were ~1 for both the low first ionization potential (FIP) elements Si and Al and the marginally high FIP element S relative to the low FIP element Fe, as is expected based on earlier observations and models for a polar coronal hole. These results are consistent with no FIP effect in a polar coronal hole

Application of federated learning techniques for arrhythmia classification using 12-lead ECG signals

Artificial Intelligence-based (AI) analysis of large, curated medical datasets is promising for providing early detection, faster diagnosis, and more effective treatment using low-power Electrocardiography (ECG) monitoring devices information. However, accessing sensitive medical data from diverse sources is highly restricted since improper use, unsafe storage, or data leakage could violate a person's privacy. This work uses a Federated Learning (FL) privacy-preserving methodology to train AI models over heterogeneous sets of high-definition ECG from 12-lead sensor arrays collected from six heterogeneous sources. We evaluated the capacity of the resulting models to achieve equivalent performance compared to state-of-the-art models trained in a Centralized Learning (CL) fashion. Moreover, we assessed the performance of our solution over Independent and Identical distributed (IID) and non-IID federated data. Our methodology involves machine learning techniques based on Deep Neural Networks and Long-Short-Term Memory models. It has a robust data preprocessing pipeline with feature engineering, selection, and data balancing techniques. Our AI models demonstrated comparable performance to models trained using CL, IID, and non-IID approaches. They showcased advantages in reduced complexity and faster training time, making them well-suited for cloud-edge architectures.Comment: Preprint of International Symposium on Algorithmic Aspects of Cloud Computing (ALGOCLOUD) 202

The Thermal Properties of Solar Flares Over Three Solar Cycles Using GOES X-ray Observations

Solar flare X-ray emission results from rapidly increasing temperatures and emission measures in flaring active region loops. To date, observations from the X-Ray Sensor (XRS) onboard the Geostationary Operational Environmental Satellite (GOES) have been used to derive these properties, but have been limited by a number of factors, including the lack of a consistent background subtraction method capable of being automatically applied to large numbers of flares. In this paper, we describe an automated temperature and emission measure-based background subtraction method (TEBBS), which builds on the methods of Bornmann (1990). Our algorithm ensures that the derived temperature is always greater than the instrumental limit and the pre-flare background temperature, and that the temperature and emission measure are increasing during the flare rise phase. Additionally, TEBBS utilizes the improved estimates of GOES temperatures and emission measures from White et al. (2005). TEBBS was successfully applied to over 50,000 solar flares occurring over nearly three solar cycles (1980-2007), and used to create an extensive catalog of the solar flare thermal properties. We confirm that the peak emission measure and total radiative losses scale with background subtracted GOES X-ray flux as power-laws, while the peak temperature scales logarithmically. As expected, the peak emission measure shows an increasing trend with peak temperature, although the total radiative losses do not. While these results are comparable to previous studies, we find that flares of a given GOES class have lower peak temperatures and higher peak emission measures than previously reported. The resulting TEBBS database of thermal flare plasma properties is publicly available on Solar Monitor (www.solarmonitor.org/TEBBS/) and will be available on Heliophysics Integrated Observatory (www.helio-vo.eu)

Factibilidad para la creación de una empresa productora de elementos derivados del bambú en el cantón Morona

En la aplicación de la investigación se buscó dar respuesta a los objetivos planteados, notando que el fin de este trabajo de titulación modalidad emprendimiento fue determinar la factibilidad para la creación de una empresa productora de elementos derivados del bambú en el Cantón Morona. La metodología inició por el planteamiento del problema describiendo el proceso creativo, seguido por el modelo de negocio y sistema de producción, en cuanto al estudio de mercado se determinó la demanda y plan de ventas, en relación al entorno jurídico se estableció que la empresa será una sociedad anónima, por último, el estudio financiero muestra los balances e indicadores de factibilidad del emprendimiento. Como resultados del esquema seguido, utilizando como procedimiento el Design Thinking se eligió una empresa fabricadora de productos de bambú nombrada Bramady, la forma de constitución elegia fue sociedad anónima, el estudio de mercado mostró como resultado que el 82% si adquiriera productos realizados de bambú, es decir que existe aceptación del producto, pues al considerar una población económicamente activa de 40.945 habitantes indicó una demanda potencial de 33.575 personas. En cuanto a los resultados del estudio financiero se identificó que el capital para iniciar las actividades de la empresa es de $7.272,70, el cual cubrirá la adquisición de los activos fijos, intangibles y el capital de trabajo, la proyección de ventas fue de$ 42.060,00 para el primer año y una utilidad neta de $1.705,51; con un VAN de$ 2.157,43 y una TIR del 19,11%. Obteniéndose una tasa mayor de oportunidad misma que es el resultado de la sumatoria de la inflación y tasa pasiva referencial del 9,95% y el periodo de recuperación de la inversión se obtendrá en 3 años 9 meses, a una proyección y evaluación de 5 años; concluyéndose finalmente que el proyecto de emprendimiento es viableIn applying the research, we sought to respond to the objectives set, noting that this degree work modality entrepreneurship aimed to determine the feasibility of creating a company producing elements derived from bamboo in Canton Morona. The methodology began with the problem statement describing the creative process, followed by the business model and production system. The market study determined the demand and sales plan. About the legal environment, it was established that the company would be a corporation. Finally, the financial study shows the venture's balance sheets and feasibility indicators. As a result of the scheme followed, using Design Thinking as a procedure, a bamboo products manufacturing company named Bramady was chosen, the form of incorporation chosen was a corporation, and the market study showed as a result that 82% would purchase products made of bamboo, that is to say, that there is acceptance of the product since considering an economically active population of 40,945 inhabitants indicated a potential demand of 33,575 people. As for the results of the financial study, it was identified that the capital to start the company's activities is $7,272.70, which will cover the acquisition of fixed assets, intangible assets, and working capital. The sales projection was$ 42,060.00 for the first year and a net profit of $1,705.51, with an NPV of$ 2,157.43 and an IRR of 19.11%. Obtaining a higher opportunity rate, which is the result of the sum of inflation and the referential passive rate of 9.95%, and the recovery period of the investment will be obtained in 3 years and nine months, at a projection and evaluation of 5 years; finally concluding that the project is viabl