Spatial and temporal variation of the different developmental stages of the sweet potato whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) in soybean

La soja es actualmente el cultivo más importante en la Argentina; a sus plagas tradicionales se ha sumado la mosca blanca, Bernisia tabaci. Los objetivos de este trabajo fueron establecer la distribución espacial de los diferentes estados de desarrollo (huevos, ninfas, pupas y adultos) de B. tabaci en lotes de soja del área central de la provincia de Córdoba (Argentina) y determinar la variación temporal de la abundancia de esos estados en dicha área. Se trabajó con muestras de lotes de dos localidades, Colonia Tirolesa y Colonia Caroya (Dpto. Colón). La comparación de abundancia entre localidades mostró variaciones entre ellas pero sólo se detectaron diferencias significativas entre adultos. Al comparar la variación de las abundancias entre fechas, sólo fue significativamente superior el aumento de ninfas y pupas durante la segunda fecha; en cuanto a los adultos se obtuvo mayor número durante la segunda fecha en Colonia Tirolesa. Cuando se analizó la variación de la abundancia tanto de inmaduros como de adultos se observaron diferencias significativas entre lotes para ambas localidades y para ambas fechas. Los resultados aquí presentados resultan de interés para ser utilizados en la toma de decisiones para el manejo de esta plaga.Soybean is now-a-days the most important crop in Argentina. Among all insect pests affecting this crop the sweetpotato whitefly, Bemisia tabaci, is becoming a new and increasingly important pest. In this paper we propose as objectives: a) to establish the spatial distribution of the different stages of B. tabaci in soybean plots in the central area of Cordoba province (Argentina) and b) to determine the spatio-temporal variation of the abundance of these stages in the same places. We worked with samples collected in to localities of Colon Department; Colonia Tirolesa and Colonia Caroya. The comparisons between localities showed a high variability between them but only the differences between adults were statistically significative. When we compared the variation of the abundance between sampling dates only the increase of nymphs and pupae were significative during the second sampling date in Colonia Tirolesa. When comparing the differences between soybean plots differences between plots in both localities and in all B. tabaci stages were observed. These results are an important input to be use in decision making for the management of this pest in the area.Fil: Cavallo, M. J.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; ArgentinaFil: Bruno, Marina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; ArgentinaFil: Irastorza, R.. Universidad Nacional de Córdoba. Facultad de Ciencias Agropecuarias; ArgentinaFil: Grilli, Mariano Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Instituto Multidisciplinar de Biología Vegetal (p). Grupo Vinculado Centro de Relevamiento y Evaluacion de Recursos Agricolas y Naturales; Argentin

Neutron background at the Canfranc Underground Laboratory and its contribution to the IGEX-DM dark matter experiment

A quantitative study of the neutron environment in the Canfranc Underground Laboratory has been performed. The analysis is based on a complete set of simulations and, particularly, it is focused on the IGEX-DM dark matter experiment. The simulations are compared to the IGEX-DM low energy data obtained with different shielding conditions. The results of the study allow us to conclude, with respect to the IGEX-DM background, that the main neutron population, coming from radioactivity from the surrounding rock, is practically eliminated after the implementation of a suitable neutron shielding. The remaining neutron background (muon-induced neutrons in the shielding and in the rock) is substantially below the present background level thanks to the muon veto system. In addition, the present analysis gives us a further insight on the effect of neutrons in other current and future experiments at the Canfranc Underground Laboratory. The comparison of simulations with the body of data available has allowed to set the flux of neutrons from radioactivity of the Canfranc rock, (3.82 +- 0.44) x 10^{-6} cm^{-2} s^{-1}, as well as the flux of muon-induced neutrons in the rock, (1.73 +- 0.22(stat) \+- 0.69(syst)) x 10^{-9} cm^{-2} s^{-1}, or the rate of neutron production by muons in the lead shielding, (4.8 +- 0.6 (stat) +- 1.9 (syst)) x 10^{-9} cm^{-3} s^{-1}.Comment: 17 pages, 8 figures, elsart document class; final version to appear in Astroparticle Physic

Using Wavelets to reject background in Dark Matter experiments

A method based on wavelet techniques has been developed and applied to background rejection in the data of the IGEX dark matter experiment. The method is presented and described in some detail to show how it efficiently rejects events coming from noise and microphonism through a mathematical inspection of their recorded pulse shape. The result of the application of the method to the last data of IGEX is presented.Comment: 14 pages, 8 figures. Submitted to Astrop. Phy

Direct detection of dark matter axions with directional sensitivity

We study the directional effect of the expected axion dark matter signal in a resonant cavity of an axion haloscope detector, for cavity geometries not satisfying the condition that the axion de Broglie wavelength $\lambda_a$ is sufficiently larger than the cavity dimensions $L$ for a fully coherent conversion, i.e. $\lambda_a \gtrsim 2\pi L$. We focus on long thin cavities immersed in dipole magnets and find, for appropriately chosen cavity lengths, an O(1) modulation of the signal with the cavity orientation with respect the momentum distribution of the relic axion background predicted by the isothermal sphere model for the galactic dark matter halo. This effect can be exploited to design directional axion dark matter detectors, providing an unmistakable signature of the extraterrestrial origin of a possible positive detection. Moreover, the precise shape of the modulation may give information of the galactic halo distribution and, for specific halo models, give extra sensitivity for higher axion masses.Comment: 14 pages, 12 figures, prepared for submission to JCA

Background studies and shielding effects for the TPC detector of the CAST experiment

Sunset solar axions traversing the intense magnetic field of the CERN Axion Solar Telescope (CAST) experiment may be detected in a Time Projection Chamber (TPC) detector, as X-rays signals. These signals could be masked, however, by the inhomogeneous background of materials in the experimental site. A detailed analysis, based on the detector characteristics, the background radiation at the CAST site, simulations and experimental results, has allowed us to design a shielding which reduces the background level by a factor of ~4 compared to the detector without shielding, depending on its position, in the energy range between 1 and 10 keV. Moreover, this shielding has improved the homogeneity of background measured by the TPC.Comment: 14 pages, 5 figures, accepted in New Journal of Physic

A novel large-volume Spherical Detector with Proportional Amplification read-out

A new type of radiation detector based on a spherical geometry is presented. The detector consists of a large spherical gas volume with a central electrode forming a radial electric field. Charges deposited in the conversion volume drift to the central sensor where they are amplified and collected. We introduce a small spherical sensor located at the center acting as a proportional amplification structure. It allows high gas gains to be reached and operates in a wide range of gas pressures. Signal development and the absolute amplitude of the response are consistent with predictions. Sub-keV energy threshold with good energy resolution is achieved. This new concept has been proven to operate in a simple and robust way and allows reading large volumes with a single read-out channel. The detector performance presently achieved is already close to fulfill the demands of many challenging projects from low energy neutrino physics to dark matter detection with applications in neutron, alpha and gamma spectroscopy.Comment: 13 pages, 13 figure

Computer modeling of radiofrequency cardiac ablation: 30 years of bioengineering research

[EN] This review begins with a rationale of the importance of theoretical, mathematical and computational models for radiofrequency (RF) catheter ablation (RFCA). We then describe the historical context in which each model was developed, its contribution to the knowledge of the physics of RFCA and its implications for clinical practice. Next, we review the computer modeling studies intended to improve our knowledge of the biophysics of RFCA and those intended to explore new technologies. We describe the most important technical details of the implementation of mathematical models, including governing equations, tissue properties, boundary conditions, etc. We discuss the utility of lumped element models, which despite their simplicity are widely used by clinical researchers to provide a physical explanation of how RF power is absorbed in different tissues. Computer model verification and validation are also discussed in the context of RFCA. The article ends with a section on the current limitations, i.e. aspects not yet included in state-of-the-art RFCA computer modeling and on future work aimed at covering the current gapsGrant RTI2018-094357-B-C21 funded by MCIN/AEI/10.13039/501100011033 (Spanish Ministerio de Ciencia, Innovación y Universidades/Agencia Estatal de Investigación)González-Suárez, A.; Pérez, JJ.; Irastorza, RM.; D Avila, A.; Berjano, E. (2022). Computer modeling of radiofrequency cardiac ablation: 30 years of bioengineering research. Computer Methods and Programs in Biomedicine. 214:1-16. https://doi.org/10.1016/j.cmpb.2021.10654611621