Ashing techniques in the determination of macronutrient contents in carrot root samples (Daucus carota L.)

Con el objeto de determinar la metodología más adecuada para la mineralización de muestras de raíz de zanahoria (Daucus carota L) se emplearon 5 técnicas por vía seca, que se compararon con el método estándar (vía húmeda). El ensayo se condujo bajo un diseño en bloques completos aleatorizados con 5 repeticiones. No se encontraron diferencias significativas en la evaluación de P y Ca, con respecto a los valores del método estándar, pero sí en la evaluación del contenido de K, calcinando a temperaturas inferiores a 550 ºC, y en la determinación de Na a 600 ºC. Se calcularon los coeficientes de correlación entre los elementos estudiados y el contenido de cenizas, encontrándose correlación altamente significativa en la mayoría de los casos. Los resultados obtenidos mostraron que las técnicas de mineralización probadas fueron efectivas para la determinación simultánea de los elementos minerales.To choose a suitable method for the digestion of carrot root samples (Daucus carota L.) five dry ashing techniques were used and compared with the standard wet ashing method. The analysis of the data was based on a randomized complete block design, with five replications. No significant differences with the standard method for P and Ca determination were found but in K evaluation, employing the dry ashing technique at a temperature lower than 550 oC, and in Na evaluation at 600 oC significant differences were obtained. Correlation coefficients between the elements studied and ash content were assessed, and a significant correlation in most cases was found. The results obtained showed that ashing techniques employed were effective.Facultad de Ciencias Agrarias y Forestale

Ashing techniques in the determination of macronutrient contents in carrot root samples (Daucus carota L.)

Con el objeto de determinar la metodología más adecuada para la mineralización de muestras de raíz de zanahoria (Daucus carota L) se emplearon 5 técnicas por vía seca, que se compararon con el método estándar (vía húmeda). El ensayo se condujo bajo un diseño en bloques completos aleatorizados con 5 repeticiones. No se encontraron diferencias significativas en la evaluación de P y Ca, con respecto a los valores del método estándar, pero sí en la evaluación del contenido de K, calcinando a temperaturas inferiores a 550 ºC, y en la determinación de Na a 600 ºC. Se calcularon los coeficientes de correlación entre los elementos estudiados y el contenido de cenizas, encontrándose correlación altamente significativa en la mayoría de los casos. Los resultados obtenidos mostraron que las técnicas de mineralización probadas fueron efectivas para la determinación simultánea de los elementos minerales.To choose a suitable method for the digestion of carrot root samples (Daucus carota L.) five dry ashing techniques were used and compared with the standard wet ashing method. The analysis of the data was based on a randomized complete block design, with five replications. No significant differences with the standard method for P and Ca determination were found but in K evaluation, employing the dry ashing technique at a temperature lower than 550 oC, and in Na evaluation at 600 oC significant differences were obtained. Correlation coefficients between the elements studied and ash content were assessed, and a significant correlation in most cases was found. The results obtained showed that ashing techniques employed were effective.Facultad de Ciencias Agrarias y Forestale

Available zinc levels in soils of Argentina

Adequate grain zinc (Zn) concentration is important because of its influence on human health. The Argentina Pampas region (APR) provides between 86% and 90% of total grain exports by the country. Soils of the Argentina Pampas region had high fertility under pristine condition but intensification of agriculture, increasing grain yields, and poor or no Zn fertilization could reduce soil available Zn. The objectives of this work were to determine the distribution of available Zn in agricultural and pristine soils of the Argentina Pampas region and its relationship with some chemical characteristics. Soil samples (0-20 cm depth) were collected and georeferenced (approximately 550 for each condition), and soil organic matter, pH, extractable phosphorus, cation exchange capacity, and available Zn by extraction with diethylenetriaminepentaacetic acid (DTPA-Zn) were measured. For geostatistical analysis, indicator kriging (non-parametric method) was utilized as interpolation method. Agriculture decreased soil organic matter, pH, extractable phosphorus and DTPA-Zn (26.9, 4.6, 57.8 and 69.5%, respectively). Relative decrease of DTPA-Zn was only significantly associated with the relative decrease of soil organic matter, although this association was low (r=0.41). Regionally, the DTPA-Zn distribution was very heterogeneous and soil organic matter, pH, extractable phosphorus and cation exchange capacity did not adequately predicted soil DTPA-Zn concentrations (r2=0.16 to 0.26). Agricultural soils of northern, northwestern and southwestern APR (approximately 12,150,000 ha) showed DTPA-Zn values below 1 mg kg-1 , and therefore would present some degree of Zn deficiency for sensitive crops.Fil: Sainz Rozas, Hernan Rene. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Puricelli, Marino Marcelo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Eyherabide, Mercedes. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Barbieri, Pablo Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Echeverria, Hernan Eduardo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Reussi Calvo, Nahuel Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Laboratorio Ferilab; ArgentinaFil: Martinez, Juan Pablo. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce. Área de Investigación en Agronomía; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

Probing Real Sensory Worlds of Receivers with Unsupervised Clustering

The task of an organism to extract information about the external environment from sensory signals is based entirely on the analysis of ongoing afferent spike activity provided by the sense organs. We investigate the processing of auditory stimuli by an acoustic interneuron of insects. In contrast to most previous work we do this by using stimuli and neurophysiological recordings directly in the nocturnal tropical rainforest, where the insect communicates. Different from typical recordings in sound proof laboratories, strong environmental noise from multiple sound sources interferes with the perception of acoustic signals in these realistic scenarios. We apply a recently developed unsupervised machine learning algorithm based on probabilistic inference to find frequently occurring firing patterns in the response of the acoustic interneuron. We can thus ask how much information the central nervous system of the receiver can extract from bursts without ever being told which type and which variants of bursts are characteristic for particular stimuli. Our results show that the reliability of burst coding in the time domain is so high that identical stimuli lead to extremely similar spike pattern responses, even for different preparations on different dates, and even if one of the preparations is recorded outdoors and the other one in the sound proof lab. Simultaneous recordings in two preparations exposed to the same acoustic environment reveal that characteristics of burst patterns are largely preserved among individuals of the same species. Our study shows that burst coding can provide a reliable mechanism for acoustic insects to classify and discriminate signals under very noisy real-world conditions. This gives new insights into the neural mechanisms potentially used by bushcrickets to discriminate conspecific songs from sounds of predators in similar carrier frequency bands

Bursts and Isolated Spikes Code for Opposite Movement Directions in Midbrain Electrosensory Neurons

Directional selectivity, in which neurons respond strongly to an object moving in a given direction but weakly or not at all to the same object moving in the opposite direction, is a crucial computation that is thought to provide a neural correlate of motion perception. However, directional selectivity has been traditionally quantified by using the full spike train, which does not take into account particular action potential patterns. We investigated how different action potential patterns, namely bursts (i.e. packets of action potentials followed by quiescence) and isolated spikes, contribute to movement direction coding in a mathematical model of midbrain electrosensory neurons. We found that bursts and isolated spikes could be selectively elicited when the same object moved in opposite directions. In particular, it was possible to find parameter values for which our model neuron did not display directional selectivity when the full spike train was considered but displayed strong directional selectivity when bursts or isolated spikes were instead considered. Further analysis of our model revealed that an intrinsic burst mechanism based on subthreshold T-type calcium channels was not required to observe parameter regimes for which bursts and isolated spikes code for opposite movement directions. However, this burst mechanism enhanced the range of parameter values for which such regimes were observed. Experimental recordings from midbrain neurons confirmed our modeling prediction that bursts and isolated spikes can indeed code for opposite movement directions. Finally, we quantified the performance of a plausible neural circuit and found that it could respond more or less selectively to isolated spikes for a wide range of parameter values when compared with an interspike interval threshold. Our results thus show for the first time that different action potential patterns can differentially encode movement and that traditional measures of directional selectivity need to be revised in such cases

The Cercal Organ May Provide Singing Tettigoniids a Backup Sensory System for the Detection of Eavesdropping Bats

Conspicuous signals, such as the calling songs of tettigoniids, are intended to attract mates but may also unintentionally attract predators. Among them bats that listen to prey-generated sounds constitute a predation pressure for many acoustically communicating insects as well as frogs. As an adaptation to protect against bat predation many insect species evolved auditory sensitivity to bat-emitted echolocation signals. Recently, the European mouse-eared bat species Myotis myotis and M. blythii oxygnathus were found to eavesdrop on calling songs of the tettigoniid Tettigonia cantans. These gleaning bats emit rather faint echolocation signals when approaching prey and singing insects may have difficulty detecting acoustic predator-related signals. The aim of this study was to determine (1) if loud self-generated sound produced by European tettigoniids impairs the detection of pulsed ultrasound and (2) if wind-sensors on the cercal organ function as a sensory backup system for bat detection in tettigoniids. We addressed these questions by combining a behavioral approach to study the response of two European tettigoniid species to pulsed ultrasound, together with an electrophysiological approach to record the activity of wind-sensitive interneurons during real attacks of the European mouse-eared bat species Myotis myotis. Results showed that singing T. cantans males did not respond to sequences of ultrasound pulses, whereas singing T. viridissima did respond with predominantly brief song pauses when ultrasound pulses fell into silent intervals or were coincident with the production of soft hemi-syllables. This result, however, strongly depended on ambient temperature with a lower probability for song interruption observable at 21°C compared to 28°C. Using extracellular recordings, dorsal giant interneurons of tettigoniids were shown to fire regular bursts in response to attacking bats. Between the first response of wind-sensitive interneurons and contact, a mean time lag of 860 ms was found. This time interval corresponds to a bat-to-prey distance of ca. 72 cm. This result demonstrates the efficiency of the cercal system of tettigoniids in detecting attacking bats and suggests this sensory system to be particularly valuable for singing insects that are targeted by eavesdropping bats

Técnicas de mineralización para la determinación de macronutrientes en muestras de raíz de zanahoria (Daucus carota L.)

Con el objeto de determinar la metodología más adecuada para la mineralización de muestras de raíz de zanahoria (Daucus carota L) se emplearon 5 técnicas por vía seca, que se compararon con el método estándar (vía húmeda). El ensayo se condujo bajo un diseño en bloques completos aleatorizados con 5 repeticiones. No se encontraron diferencias significativas en la evaluación de P y Ca, con respecto a los valores del método estándar, pero sí en la evaluación del contenido de K, calcinando a temperaturas inferiores a 550 ºC, y en la determinación de Na a 600 ºC. Se calcularon los coeficientes de correlación entre los elementos estudiados y el contenido de cenizas, encontrándose correlación altamente significativa en la mayoría de los casos. Los resultados obtenidos mostraron que las técnicas de mineralización probadas fueron efectivas para la determinación simultánea de los elementos minerales

Early parenteral nutrition in enterectomized dogs

ABSTRACT: The aim of this study was to explore the role of early central parenteral nutrition support with and without lipid emulsion in enterectomized dogs undergoing small bowel partial resection. Enterectomized dogs often cannot be fed properly via an oral or enteral route immediately post-surgery. After enterectomy, the animals received parenteral nutrition or crystalloid solution until they were able to voluntarily take in an oral diet. All dogs were recruited at the University of Sao Paulo veterinary teaching hospital. Eighteen dogs with intussusception, a foreign intestinal body, linear foreign intestinal body, or intussusception associated with a foreign intestinal body underwent enterectomy surgery and were randomly assigned to receive one of three treatments: crystalloid solution (CS group), parenteral nutrition with a mix of glucose and amino acids (GA group) or parenteral nutrition with a mix of glucose, amino acids and lipids (GAL group). A serum chemistry panel and complete blood count were collected prior to surgery and at the end of the study. Albumin increased in the GA and GAL group (p=0.042 and p=0.038 respectively) after hospitalization, but no significant differences were identified among the groups. Body weight decreased by 4.9% (p=0.042) in the CS group, but there were no significant changes in the GAL and GA groups. There was a significant decrease in the recovery scores in the GA and GAL groups during hospitalization (p=0.039 in both groups). Early parenteral nutrition was beneficial for patient recovery in post-surgical small bowel partial resection, indicating better quality, and no major complications or side effects were observed during the hospitalization period in the studied dogs