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Social, economic and political changes in the current global context have introduced in recent decades a strong demand and production of information, greatly enhanced by the advances that have arisen with the application of new technologies. These advances had a radical impact on the construction of new consumption, interaction and learning scenarios for society in general. Likewise, reading habits were also modified with the arrival of electronic books or e-books, which have their own meanings and modes of use. This article introduces us to the transition from printed to electronic books, the characteristics of the latter, and the challenges for libraries and librarians today.

The new information and communication technologies were generating new interfaces for accessing bibliographic material, with which diverse ways of reading, writing and thinking about the interaction between the writer and his potential receivers were installed. This panorama invites us to make a brief review of the current situation of books, libraries and librarians in our country.

This article presents a new method for transferring calibration from a reference photometer, referred to as the "master'', to a secondary photometer, referred to as the "field'', using a synergetic approach when master and field instruments have different spectral bands. The method was first applied between a PFR, (Precision Filter Radiometer) instrument from the World Optical Depth Research and Calibration Center (WORCC) considered the reference by the WMO (World Meteorological Organization), and a CE318-TS photometer, the standard photometer used by AERONET (AErosol RObotic NETwork). These two photometers have different optics, sun-tracking systems and spectral bands. The Langley Ratio method (LR) proposed in this study was used to transfer calibration to the closest spectral bands for 1-minute synchronous data, for airmasses between 2 and 5, and was compared to the state of the art Langley calibration technique. The study was conducted at two different locations, Izaña Observatory (IZO) and Valladolid, where measurements were collected almost simultaneously over a six-month period under different aerosol regimes. In terms of calibration aspects, our results showed very low relative differences and standard deviations in the calibration constant transferred in Izaña from PFR to Cimel, up to 0.29 % and 0.46 %, respectively, once external factors such as different field-of-view between photometers or the presence of calibration issues were considered. However, these differences were higher in the comparison performed at Valladolid (1.04 %) and in the shorter wavelengths spectral bands (up to 0.78 % in Izaña and 1.61 % in Valladolid). Additionally, the LR method was successfully used to transfer calibrations between different versions of the CE318-T photometer, providing an accurate calibration transfer (0.17 % to 0.69 %) in the morning LRs, even when the instruments had differences in their central wavelengths (Δλ up to 91 nm). Overall, our results indicate that the LR method is a useful tool not only for transferring calibrations but also for detecting and correcting possible instrumental issues. This is exemplified by the temperature dependence on the two Cimel UV spectral bands, which was estimated by means of the LR method to be ~ -0.09x10-2/° in the case of 380 nm and ~ -0.03x10x10-2/° in the case of 340 nm. This estimation served us to implement the first operative temperature correction on ultraviolet (UV) spectral bands.

This study explores the potential to retrieve aerosol properties with the GRASP algorithm (Generalized Retrieval of Atmosphere and Surface Properties) using as input measurements of zenith sky radiance (ZSR), which are sky radiances measured in the zenith direction, recorded at four wavelengths by a ZEN-R52 radiometer. To this end, the ZSR measured at 440, 500, 675 and 870 nm by a ZEN-R52 (ZSRZEN), installed in Valladolid (Spain), is employed. This instrument is calibrated intercomparing the signal of each channel with coincident ZSR values simulated (ZSRSIM) at the same wavelengths with a radiative transfer model (RTM). These simulations are carried out using the GRASP forward module as RTM and the aerosol information from a collocated CE318 photometer belonging to the AERONET network (Aerosol and Robotic Network) as input. Dark signal and the signal dependence on temperature are characterized and included in the calibration process. The uncertainties on each channel are quantified by an intercomparison with a collocated CE318 photometer, obtaining lower values for shorter wavelengths; between 3 % for 440 nm and 21 % for 870 nm. The proposed inversion strategy for the aerosol retrieval using the ZSRZEN measurements as input, so-called GRASP-ZEN, assumes the aerosol as an external mixture of five pre calculated aerosol types. A sensitivity analysis is conducted using synthetic ZSRZEN measurements, pointing out that these measurements are sensitive to aerosol load and type. It also assesses that the retrieved aerosol optical depth (AOD) values in general overestimates the reference ones by 0.03, 0.02, 0.02 and 0.01 for 440, 500, 675, 870 nm, respectively. The calibrated ZSRZEN measurements, recorded during two and half years at Valladolid, are inverted by GRASP-ZEN strategy to retrieve some aerosol properties like AOD. The retrieved AOD shows a high correlation with respect independent values obtained from the collocated AERONET CE318 photometer, with a determination coefficient (r2) about 0.86, 0.85, 0.79 and 0.72 for 440, 500, 675 and 870 nm, respectively, and finding uncertainties between 0.02 and 0.03 with respect to the AERONET values. Finally, it is studied the goodness of other retrieved aerosol properties like aerosol volume concentration for total, fine and coarse modes.

Durante la erupción del volcán de Cumbre Vieja, en la isla de La Palma en 2021, la Agencia Estatal de Meteorología (AEMET), en calidad de Servicio Nacional y Autoridad Meteorológica del Estado, prestó diferentes servicios de apoyo al Comité Científico y al Comité Asesor del Plan de Emergencias Volcánicas de Canarias (PEVOLCA). Parte de sus actividades abarcaron la vigilancia y predicción meteorológica, la monitorización y predicción del transporte del penacho volcánico, y la valoración del impacto de las emisiones de gases y cenizas de la erupción volcánica en la calidad del aire en la isla de La Palma y en la región de Canarias.

The implementation of calves feeding programs is one of the ways to achieve greater efficiency in dairy production. The aim of this study was to evaluate the cost of feeding milk-fed Holstein calves. In addition to analyze their development and effectiveness up to the weaning stage. Sixty calves were randomly selected, separated from their dams at birth and individually housed in wooden cages previously washed and disinfected. The treatments were as follows: T1 = 6L for 57 days, T2 = 6L for 50 days, T3 = 6L for 45 days of life. The variables considered to evaluate productivity from birth to weaning were weight and withers height, daily gain and total weight gain. Daily weight gain was calculated by dividing total weight gain by the number of days in lactation. Feed consumption was measured during the entire lactation of the animals. For the economic analysis, the price of milk and the cost of starter concentrate were considered. Statistical analysis of the variables was performed by analysis of variance and comparison of means was performed by a Tukey test. The value of P ≤ 0.05 was used to consider statistical difference. No statistical differences (P ≤ 0.05) were observed for the variables evaluated; withers height, birth to weaning weight, daily gain and total weight gain. Regarding feed consumption, a statistical difference (P ≤ 0.001) was observed in favor of treatment T3, where feed cost was cheaper, but it was also the most efficient; treatment T1, was the most expensive and the least efficient. Considering the above, greater growth is achieved in calves receiving less milk and consuming more starter.

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Fil: Gonzáles, Ramiro. Universidad Juan Agustín Maza. Colegio secundario (CUMAZA). Mendoza. República Argentina. Fil: Rodiloso, Ignacio. Universidad Juan Agustín Maza. Colegio Secundario (CUMAZA). Mendoza. República Argentina. Trabajo realizado por alumnos de primer año en el marco de la asignatura de ciencias naturales, del tema célula y sus procesos. Los alumnos realizaron un microscopio con una linterna láser, una jeringa descartable y agua. Utilizaron los principios de óptica como refracción de la luz y lentes, obtuvieron 2000 aumentos. Los objetivos de este trabajo fueron: Comprender y visualizar procedimiento científico y normas de Bioseguridad, entender el funcionamiento de un microscopio, observar diferentes estructuras y tipos de células y comprender procesos biológicos como la fermentación.

The breeding of replacements is fundamental in any production system, since the heifers are the one that will replace in a certain time the cows that gradually leave the exploitation. Probiotics can form part of the composition of different types of products, including foods (functional foods), medicines and dietary supplements. The objective of this study was to evaluate the feeding cost of Holstein heifers fed with whole milk added with Bacillus subtilis PB6. 60 new-born animals were used, randomly included in 1 of 3 treatments. The treatments were as follows: T1 = control, T2 = 10 g heifer day. The First Take within 20 min after birth, T3 = 10 g heifer day. The first takes between 12 and 24 h after birth. In All treatments 432 L of pasteurized whole milk was supplied divided into two outlets day 07:00 and 15:00 respectively, for 60 days, the addition of Bacillus subtilis PB6 was carried out in the milk tub at the time of feeding them. The first intake of colostrum (2 L•intake) per animal, was supplied within 2 h after birth, then provided a second 6 h after the first. The variables to evaluate the cost of feeding were considered milk consumption and concentrate during the first 60 days of life. It Was concluded that in the evaluated variables no statistical difference was observed P