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"Mal de Rio Cuarto", is the most important virus disease of corn, Zea mays L., in Argentina. It is caused by the Mal de Rio Cuarto virus (family Reoviridae, genus Fijivirus. MRCV), which is a persistent virus transmitted by Delphacodes kuscheli (Fennah 1955) (Hemiptera: Delphacidae). Because corn is not a natural host of D. kuscheli, it has little protection from this pest. In contrast, wheat, Triticum aestivum L., is one of the main hosts of this vector and a reservoir of MRCV. The aim of this work was to identify genes involved in antixenosis, antibiosis, and tolerance of infestation by D. kuscheli in wheat, which might be used to reduce the population level of this vector on corn. A set of recombinant dihaploid (RDH) lines for chromosome 6A derived from the F1 cross between 'Chinese Spring' (CS) X 'Chinese Spring (Synthetic 6A)' (S6A) substitution line, was used for mapping. The S6A parental line is resistant to the MRCV vector. Antixenosis, antibiosis, and tolerance were evaluated using conventional tests in controlled environmental conditions. Most of the RDH and S6A showed higher levels of antixenosis against D. kuscheli than the parental line CS. The RDH lines showed highly significant antibiosis in terms of the duration of first, third, and fifth nymphal instars, developmental time (days), survival and fecundity. There were highly significant differences in the tolerance to D. kuscheli based on the chlorophyll content of the first and second leaves, foliar area, and aboveground fresh and dry weights. The duration of the fifth nymphal instar and the developmental period were significantly associated with Xgwm1017 marker loci, located at 48 cM on 6AL. Another quantitative trait locus accounting for the variation in chlorophyll content of the first leaf was associated with the interval between loci Xgwm459 and Xgwm334a, located in the telomeric region of the 6AS chromosome arm. The alleles with positive effects came from S6A. Antibiotic resistance of RDH could be useful for controlling the population increase of the MRCV vector on wheat, because prolonging the duration of development increases the period between two subsequent generations, so reducing the abundance of infective populations colonizing corn.

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Sipha maydis (Passerini) is a new aphid pest of cereals and cultivated and wild grasses in Argentina. This species was recently introduced into America, and nothing is known of its distribution or host range in South America. A better understanding of its biology is likely to facilitate control. This article records 1) the distribution and 2) the host range of S. maydis in Argentina. Over the period 2004-2006 samples were collected from 32 populations at several localities in Argentina. The number of S. maydis, accompanying aphid species, and the host from which they were collected were recorded. The distribution of S. maydis ranged from 32 degrees 52' to 42 degrees 03' S, and from 57 degrees 41' to 71 degrees 24' W, bounded by isothermals 18 and 10 degrees C and isohyets 200-400 and <1,200 mm. No S. maydis were found in the subtropical region, even in winter. In the field, the different populations showed very different host preferences. S. maydis was found mainly on cultivated barley and wheat and on wild Bromus spp. and Sorghum halepense (L.) Pers. No aphids were found on maize, Zea mays L. Most of the damage to winter cereal crops occurred at the seedling stage in early autumn and of adult plants when infestations occurred in late spring. In the 4 yr after the first record of S. maydis in Argentina, it colonized a huge area similar to that colonized by Diuraphis noxia (Mordvilko) in 10 yr. The wide range of regions, hosts and climatic conditions this species is adapted to is likely to make the control of this pest very difficult.

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This work proposes multichannel acquisition of lung sounds by a microphone array, feature extraction by a multivariate AR (MAR) model, dimensionality reduction of the feature vectors (FV) by SVD and PCA and, their classification by a supervised neural network. A microphone array of 25 sensors was attached on the thoracic surface of the subjects, who were breathing at 1.5 L/sec. The supervised neural network used the backpropagation learning algorithm based on the Levenberg-Marquardt rule. Figures of merit for the classification task by the neural net include the percentage of correct classification during training, testing and validation phases as well as sensitivity, specificity and performance. MAR in combination with PCA provided the best average percentage of correct classification with acoustic information not seen by the neural network during the training phase (87.68%). The results state the advantages of a microphone array for the classification of normal and abnormal acoustic pulmonary information in diffuse interstitial pneumonia and for this goal, the authors assume that not only the crackles and their number indicates the severity of the disease, but the basal respiratory signal could be also affected.

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An experiment was performed to study the formaldehyde protective effect on the ensilaged whole peanut plant protein (21.5% CP). The experimental design consisted in four treatments 5, 10, 15 and 20% formaldehyde, which was added in the proportion of 5 lt, per ton. A control group without any formaldehyde was also included. There were no significant differences in regard to pH among treatments (5.56 to 5.70). Ammonia concentration dropped significantly in all treatments, a finding which suggests a protective effect on protein nitrogen degradation to non-protein nitrogen (NH3). A lactic acid fermentation was observed, without any difference between treatment and the control group. Nevertheless, there was a reduction in propionic acid and ethanol concentration in all the silages. Therefore, it is concluded that there was an inhibition of the fermentation process in all the silages treated, and that the addition of formaldehyde at the 5% level is a satisfactory way of protecting this type of feed.

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Este estudio tuvo como objetivo investigar el formaldehido sobre la proteina de la planta de cacahuate (21.5% PC). Se diseno un experimento con cuatro tratamientos (5, 10, 15 y 20% de formaldehido) y un grupo testigo, con litros por tonelada. El pH no fue modificado por los tratamientos (5.56 a 5.70).El porcentaje de amoniaco fue significativamente mas bajo en los ensilados tratados que en el testigo, lo que sugiere cierta proteccion de la degradacion del nitrogeno no proteinico a nitrogeno amoniacal. Se observo una fermentacion acida, de tipo lactico, no haviendo diferencia entre tratamiento y grupo testigo. Sin embargo, si se constato una disminucion de acido propionico y etanol en los ensilados tratados. Por lo tanto, se concluye que existe cierta inhibicion de la fermentacion en los ensilados tratados, aconsejandose asi el empleo de formol al 5%, como una forma satisfactoria de aprovechar mas positivamente este alimento

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Tomamos para nuestro estudio, a los recien nacidos con sospecha o con cuadro clínico evidente de lúes congénita, que ingresaron al servicio de CIREN desde el mes de agosto/86 hasta junio/87. Durante el tiempo que duró el estudio se produjeron 2.322 nacimientos en la maternidad G. Urquidi de los cuales 12 tuvieron características clínicas de lúes congénita sintomática, es decir 4.5 del total de internaciones a CIREN.

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