Banks in trouble? A Early Warning System for the Prevention of Banking Crisis.

The regulatory and supervisory financial authorities have tried various methods to find an effective procedure in developing an early warning system of banking crises. Logistic regression models have been used but have shown some weaknesses, so we need new and better methods. The banking crisis occurred in the Dominican Republic between 2002 and 2004 has been used to compare the effectiveness of the logistic regression method over the use of Support Vector Machines (SVM) for the detection of banking crisis. In the analysis 30 financial indicators are used to determine which ones are most appropriate to build a model able to classify banks. In this context, the SVM method produced better results than logistic regression, in detecting problem banks and contradict the findings of other studies that ask about the ineffectiveness of the financial indicators to identify banking crises in emerging economies.Banking crisis; logistic regression; support vector machines

Radical decisions in cancer: Redox control of cell growth and death

Free radicals play a key role in many physiological decisions in cells. Since free radicals are toxic to cellular components, it is known that they cause DNA damage, contribute to DNA instability and mutation and thus favor carcinogenesis. However, nowadays it is assumed that free radicals play a further complex role in cancer. Low levels of free radicals and steady state levels of antioxidant enzymes are responsible for the fine tuning of redox status inside cells. A change in redox state is a way to modify the physiological status of the cell, in fact, a more reduced status is found in resting cells while a more oxidative status is associated with proliferative cells. The mechanisms by which redox status can change the proliferative activity of cancer cells are related to transcriptional and posttranscriptional modifications of proteins that play a critical role in cell cycle control. Since cancer cells show higher levels of free radicals compared with their normal counterparts, it is believed that the anti-oxidative stress mechanism is also increased in cancer cells. In fact, the levels of some of the most important antioxidant enzymes are elevated in advanced status of some types of tumors. Anti-cancer treatment is compromised by survival mechanisms in cancer cells and collateral damage in normal non-pathological tissues. Though some resistance mechanisms have been described, they do not yet explain why treatment of cancer fails in several tumors. Given that some antitumoral treatments are based on the generation of free radicals, we will discuss in this review the possible role of antioxidant enzymes in the survival mechanism in cancer cells and then, its participation in the failure of cancer treatments

Inter-annual variability in Prosopis caldenia pod production in the Argentinean semiarid pampas: A modelling approach

Producción CientíficaThe driest part of the Argentinean pampas is occupied by semiarid woodlands dominates by Prosopis caldenia Burkart (Calden). Calden pods are a highly valuable fodder supplement for livestock but its production is highly variable. Our objective was to analyze and model the temporal pattern in inter-annual variability of Calden pod production. Our key hypothesis is that weather conditions are the main determinant of the pod masting behavior. Tree size and climatic variables were evaluated as explanatory covariates using a zero-inflated log-normal modelling approach. The proposed final model structure incorporated 25 parameters, including four variance components, two intercepts for both the logistic and the log-normal parts of the model, and nineteen parameters associated with fixed effects. Climate had a strong influence on the flowering-fruiting Calden process and on the inter-annual variability of the final pod production at the tree level. Temperatures during bud breaking, flowering and fruit shedding, together with the precipitation from the final month of fruit shedding and the total amount of the prior vegetative cycle, were the main weather covariates that affect the processes

Heating of the magnetized solar chromosphere by partial ionization effects

In this paper, we study the heating of the magnetized solar chromosphere induced by the large fraction of neutral atoms present in this layer. The presence of neutrals, together with the decrease with height of the collisional coupling, leads to deviations from the classical MHD behavior of the chromospheric plasma. A relative net motion appears between the neutral and ionized components, usually referred to as ambipolar diffusion. The dissipation of currents in the chromosphere is enhanced orders of magnitude due to the action of ambipolar diffusion, as compared to the standard ohmic diffusion. We propose that a significant amount of magnetic energy can be released to the chromosphere just by existing force-free 10--40 G magnetic fields there. As a consequence, we conclude that ambipolar diffusion is an important process that should be included in chromospheric heating models, as it has the potential to rapidly heat the chromosphere. We perform analytical estimations and numerical simulations to prove this idea.Comment: Accepted for publication by The Astrophysical Journa

Numerical simulations of conversion to Alfven waves in sunspots

We study the conversion of fast magneto-acoustic waves to Alfven waves by means of 2.5D numerical simulations in a sunspot-like magnetic configuration. A fast, essentially acoustic, wave of a given frequency and wave number is generated below the surface and propagates upward though the Alfven/acoustic equipartition layer where it splits into upgoing slow (acoustic) and fast (magnetic) waves. The fast wave quickly reflects off the steep Alfven speed gradient, but around and above this reflection height it partially converts to Alfven waves, depending on the local relative inclinations of the background magnetic field and the wavevector. To measure the efficiency of this conversion to Alfven waves we calculate acoustic and magnetic energy fluxes. The particular amplitude and phase relations between the magnetic field and velocity oscillations help us to demonstrate that the waves produced are indeed Alfven waves. We find that the conversion to Alfven waves is particularly important for strongly inclined fields like those existing in sunspot penumbrae. Equally important is the magnetic field orientation with respect to the vertical plane of wave propagation, which we refer to as "field azimuth". For field azimuth less than 90 degrees the generated Alfven waves continue upwards, but above 90 degrees downgoing Alfven waves are preferentially produced. This yields negative Alfven energy flux for azimuths between 90 and 180 degrees. Alfven energy fluxes may be comparable to or exceed acoustic fluxes, depending upon geometry, though computational exigencies limit their magnitude in our simulations.Comment: Accepted for publication in Ap

Endogenous topoisomerase II-mediated DNA breaks drive thymic cancer predisposition linked to ATM deficiency

The ATM kinase is a master regulator of the DNA damage response to double-strand breaks (DSBs) and a well-established tumour suppressor whose loss is the cause of the neurodegenerative and cancer-prone syndrome Ataxia-Telangiectasia (A-T). A-T patients and Atm−/− mouse models are particularly predisposed to develop lymphoid cancers derived from deficient repair of RAG-induced DSBs during V(D)J recombination. Here, we unexpectedly find that specifically disturbing the repair of DSBs produced by DNA topoisomerase II (TOP2) by genetically removing the highly specialised repair enzyme TDP2 increases the incidence of thymic tumours in Atm−/− mice. Furthermore, we find that TOP2 strongly colocalizes with RAG, both genome-wide and at V(D)J recombination sites, resulting in an increased endogenous chromosomal fragility of these regions. Thus, our findings demonstrate a strong causal relationship between endogenous TOP2-induced DSBs and cancer development, confirming these lesions as major drivers of ATM-deficient lymphoid malignancies, and potentially other conditions and cancer types.Junta de Andalucía SAF2010-21017, SAF2013-47343-P, SAF2014-55532-R, SAF2017-89619-R, CVI-7948European Research Council ERC-CoG-2014-64735

Real-Time Implementation of qZSC for MVDC to Microgrids Link

Nowadays, power systems require new solutions to integrate renewable energies. In this paper, microgrids linked to MVDC are proposed through quasi-impedance-source converters to improve system reliability. Several prototypes are implemented using real-time platforms to analyze the system behavior, but the real-time implementation of the shoot-through state of the qZSC requires a very low time-step and sample time, which is not easy to achieve. The results obtained with these prototypes are included. Finally, a satisfactory solution is presented, implementing the power system in Typhoon HIL-402, the qZSC control in dSPACE MicroLabBox, and generating the gate signals in the FPGA included in the MicroLabBox platform. © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved

The truncation of the disk of NGC 4565: Detected up to z=4 kpc, with star formation, and affected by the warp

Context: The hierarchical model of galaxy formation suggests that galaxies are continuously growing. However, our position inside the Milky Way prevents us from studying the disk edge. Truncations are low surface brightness features located in the disk outskirts of external galaxies. They indicate where the disk brightness abruptly drops and their location is thought to change dynamically. In previous analyses of Milky Way-like galaxies, truncations were detected up to 3 kpc above the mid-plane but whether they remain present beyond that height remains unclear. Aims: Our goal is to determine whether truncations can be detected above 3 kpc height in the Milky Way-like galaxy NGC 4565, thus establishing the actual disk thickness. We also aim to study how the truncation relates to disk properties such as star formation activity or the warp. Methods: We perform a vertical study of the disk of NGC 4565 edge in unprecedented detail. We explore the truncation radius at different heights above/below the disk mid-plane (0<z<8 kpc) and at different wavelengths. We use new ultra-deep optical data ($\mu_{g,\rm{lim}}=30.5$ mag arcsec$^{-2}$; $3 \sigma$ within $10 \times 10$ arcsec$^{2}$ boxes) in the $g$, $r$ and $i$ broad bands, along with near- and far-ultraviolet, H$\alpha$, and \ion{H}{i} observations. Results: We detect the truncation up to 4 kpc in the $g$, $r$ and $i$ ultra-deep bands which is 1 kpc higher than in any previous study for any galaxy. The radial position of the truncation remains constant up to 3 kpc while higher up it is located at a smaller radius. This result is independent of the wavelength but is affected by the presence of the warp. Conclusions: We propose an inside-out growth scenario for the formation of the disk of NGC 4565. Our results point towards the truncation feature being linked to a star-forming threshold and to the onset of the disk warp.Comment: 27 pages, 18 figures (incl. 2 appendix); accepted for publication in A&A; Fixed labels in Fig.

Números de curva de escurrimiento determinados para una microcuenca aforada con suelos argiudoles de permeabilidad moderada

El escurrimiento asociado a la erosión hídrica determina a menudo un costo ambiental debido a la pérdida de agua, suelo, nutrientes y materia orgánica de las tierras agrícolas, así como el transporte de contami nantes hacia los cuerpos de agua. Un procedimiento utilizado para estimar escurrimiento superficial en microcuencas es el método del Número de Curva (CN) (USDA) el cual es empleado en diversos modelos hidrológicos de estimación de erosión hídrica y de generación y transporte de contaminantes. Debido a su carácter empírico, resulta necesario contar con valores calibrados para las condiciones locales en las que el mismo se aplica. Se registraron 20 meses continuos de aforos en una microcuenca agrícola dominada por la Serie Arroyo Dulce bajo siembra directa (SD) continua de la cual no había información hidrológica pre via. El periodo analizado se caracterizó por incluir 83 lluvias, algunas muy intensas con periodo de retorno de 10 años y se registraron 13 eventos de escurrimiento que permitieron contrastar las hipótesis plantea das. Por un lado, se corroboró una tendencia al comportamiento hidrológico de tipo “estándar” tal como lo menciona Hawkins y otros investigadores, asociándose a un escurrimiento de tipo “hortoniano”. Por otra parte, los CN obtenidos resultaron coherentes con las propiedades intrínsecas del suelo dominante, la Serie Arroyo Dulce, un Argiudol típico profundo y de moderada permeabilidad. Los CN tendieron a valores entre 60 y 70 para lluvias extraordinarias y la mediana se ubicó en CN=71 con valores extremos entre 63 (suelo seco) y 87 (suelo húmedo). La comparación con los resultados obtenidos previamente en una microcuenca aforada con suelos Argiudoles vérticos de la Serie Ramallo (mediana=CN 82), permitió separar claramente ambas series.The runoff associated with water erosion often determines an environmental cost due to the loss of water, soil, nutrients, and organic matter from agricultural land as well as the transport of pollutants to water bodies. A widely used procedure for estimating surface runoff in small watersheds is the curve number me thod (CN) (USDA) which is used in various hydrological models, water erosion estimation and contaminant generation and transport models. Due to its empirical nature, it is necessary to have calibrated values for the local conditions in which it is applied. We registered 20 continuous months of runoff measurements in a small agricultural gauged watershed dominated by the Arroyo Dulce series under continuous no tillage of which there was no prior hydrological information. The period analyzed was characterized by the occurren ce of 83 rains some of them very intense with a return period of 10 years and there were 13 runoff events that allowed to contrast the hypotheses raised. On the one hand, a trend of standard hydrological behavior was corroborated as mentioned by Hawkins and other researchers, associated with a “hortonian” runoff response. Moreover, the CNs obtained were consistent with the intrinsic properties of the dominant soil, the Arroyo Dulce series, a deep typical Argiudoll with moderate permeability. CN tended to values between 60 and 70 for extraordinary rainfall and the median was located at CN-71 with extreme values between 63 (dry soil) and 87 (wet soil). Comparison with the results previously obtained in a small, gauged watershed with vertic Argiudoll soil of the Ramallo Series (median CN 82), made it possible to clearly separate both series.Fil: Sainz, Daiana Soledad. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación de Suelos; Argentina.Fil: Behrends Kraemer, Filipe. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Carfagno, Patricia. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Investigación de Suelos; Argentina.Fil: Eiza, Maximiliano Joaquín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Chagas, Celio. Universidad de Buenos Aires. Facultad de Agronomía; Argentina

Transformer‐Based Z‐Source Inverter with MVDC Link

Z‐source inverters have attracted considerable attention in renewable energy systems like photovoltaic (PV) systems due to advantages such as buck–boost power conversion in single stage, shoot-through capability, and wide range of input voltage regulation. Transformer-Based Z-source inverters (TransZSI) based on magnetically coupled inductors and reduced number of passive components can be used to improve the boost capacity of these inverters, and to increase the voltage levels. Medium voltage DC (MVDC) is being used more and more in distribution grids and renewable energy systems. This paper presents a transZ-source inverter with MVDC link where renewable energy systems and energy storage systems can be integrated. The active and reactive powers and DC voltage are controlled by acting on the modulation index and shoot-through duty cycle of the converter. The trans-Z-source inverter is evaluated under different operating conditions to illustrate its suitable operation. © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved