Delirios, intencionalidad y racionalidad: análisis crítico del enfoque de Donald Davidson Vilatta, María Emilia El presente trabajo tendrá por objetivo evaluar los alcances y límites del enfoque de Donald Davidson para ofrecer una interpretación intencional de sujetos que padecen distintos tipos de delirios. Como estrategia metodológica me propondré examinar este debate a la luz de las siguientes categorías diagnósticas: trastorno delirante, esquizofrenia de tipo paranoide y esquizofrenia de tipo desorganizado. Sostendré que la concepción davidsoniana puede extenderse sin mayores inconvenientes a sujetos diagnosticados con trastornos delirantes y esquizofrenia de tipo paranoide. Asimismo, siquiera parcialmente, también puede emplearse para dar cuenta de algunos casos de esquizofrenia de tipo desorganizado. No obstante, para que esta extensión sea posible, será preciso reconsiderar el holismo propuesto por Davidson y matizar algunas de sus afirmaciones respecto a las condiciones para la atribución de pensamiento.

Becoming a tutor: student scaffolding in a game-based classroom Monjelat, Natalia Gabriela; Méndez, Laura Marcela; Lacasa, Pilar Student interaction in school contexts is a topic that has been researched from many different perspectives. However, the role of students as tutors scaffolding other peers is not normally addressed, since studies are usually focused on the teacher. Moreover, considering the many technologies that can support students’ work nowadays, studies describing specific practices are still needed in order to understand the many possibilities and constraints that can emerge from the use of these tools in the field of education. This exploratory case study aims to extend research on scaffolding between students, presenting data from an ethnographic study where a commercial video game was introduced as part of the curricular activities. Analytically, the scaffolding metaphor is the departing point to describe in detail how the scaffolding process took place, focusing on its purposes and on the role of students as tutors. Our findings reveal how students offered mostly procedural scaffoldings, performing tutor functions such as highlighting relevant features, reducing levels of freedom or controlling the frustration. Results highlight that students can perform scaffolds, and this should be considered as part of the classroom design, making this process visible. Moreover, specific features of the video game enhanced these interactions, which should also be considered when designing game learning environments in the future.

Procesos postdepositacionales del registro cerámico de cazadores recolectores de la Provincia de La Pampa; Post-depositional processes of surface ceramic record of hunter-gatherers from La Pampa province Ozán, Ivana Laura; Beron, Monica Alejandra La diversidad, frecuencia y distribución espacial de la tecnología cerámica son propiedades que dependen del grado de preservación del registro. En este sentido, a través de una metodología que integra aspectos tecnológicos, tafonómicos, ambientales y experimentales, este trabajo se propone analizar el grado de integridad del material cerámico superficial perteneciente a contextos de cazadores recolectores del centro-este y sudoeste de la Provincia de La Pampa, Argentina. Los resultados del análisis del material arqueológico perteneciente a siete sitios muestran que el ambiente explican parcialmente el grado de meteorización y fragmentación de la muestra. Complementariamente, ciertas características tecnológicas como la baja cohesividad, la alta porosidad y la escasez de inclusiones en las pastas parecen tener un peso mayor en el grado de preservación de los conjuntos, mientras que el grosor de los tiestos parece ser un aspecto clave en el índice de fragmentación del material cerámico. Paralelamente, en el trabajo experimental, el ambiente explica más claramente el grado de meteorización del registro. Asimismo, la experimentación señala que ciertas propiedades tecnológicas como la porosidad, la cohesividad, el color de la pasta y el acabado de superficie pueden cambiar en un lapso temporal muy breve. Todo esto invita a pensar acerca de cuáles son las categorías relevantes para pensar tipologías y hacer inferencias sobre el registro arqueológico.; The diversity, frequency and distribution of superficial pottery depend on its preservation degree, among other factors. In this direction, the present contribution aims to present a methodological design in order to discuss how and in which extent technological properties and postdepositional processes affect the integrity of the superficial ceramic record, by considering seven ceramic assemblages corresponding to hunter-gatherer populations from the centre-east and south-west of La Pampa province, Argentina. Through this analysis, it is concluded that environmental variables only explain partially the weathering degree and fragmentation of the ceramic assemblages. Complementary, technological aspects such as low cohesiveness, high porosity, and rare paste inclusions play a major role in the weathering explanation, whereas the thickness seems to be directly link with the ceramic fragmentation. In contrast, experimental analysis indicate that environmental variables are the main cause of ceramic weathering. Additionally, in the experimental test, technological properties such as the presence of cavities, cohesiveness and surface treatment have changed substantially only in a short period of time. Thus, the relevant categories chosen to build typologies have first to be discussed in order to make accurate archaeological interpretations.

The structure of the bulk and the (001) surface of V2O5. A DFT+U study Ranea, Victor Alejandro; Dammig Quiña, Pablo Leandro GGA(PW91)+Uis applied to the calculation of the structure (lattice parameters) and the electronic structure of theV2O5 bulk and its (001) surface for different values ofUeff used in the literature (0.0, 3.0 and 6.6 eV). Similar surface lattice parameters are calculated for the (001) surface and for the bulk, as well as similar electronic structures. The calculated lattice parameters (a and b for the surface and a, b and c for the bulk) are in good agreement with experimental results. It seems that there is no strong correlation between the calculated lattice parameters and the value ofUeff. The calculated width of the valence band keeps the value of 5 eVfor the three studiedUeff. However, the energy gap between the valence and the conduction bands increases with the value ofUeff.Ueff=3.0 eV seems to be the most adequate value to describe the energy gap after comparison with experimental results. Electronic density contour plots indicate that for a larger (smaller)Ueff the accumulated charge in the V-O(1) bond is overestimated (underestimated). The contour plots (in the a direction) show that the charge distribution V-O(3) is less correlated withUeff than the charge distribution V-O(1), whereas charge distribution V-O(2) seems not to be corretaled withUeff. The energy gap between the valence and the conduction bands seems to be strongly related with the charge distribution in the V-O(1) bond. The V-O(1) bond stability seems to be correlated withUeff. However, the stability of the V-O(2) and V-O (3) bonds seems not to be strongly affected byUeff.

Influence of background size, luminance and eccentricity on different adaptation mechanisms Gloriani, Alejandro H.; Matesanz, Beatriz M.; Barrionuevo, Pablo Alejandro; Arranz, Isabel; Issolio, Luis Alberto; Mar, Santiago; Aparicio, Juan A. Mechanisms of light adaptation have been traditionally explained with reference to psychophysical experimentation. However, the neural substrata involved in those mechanisms remain to be elucidated. Our study analyzed links between psychophysical measurements and retinal physiological evidence with consideration for the phenomena of rod-cone interactions, photon noise, and spatial summation. Threshold test luminances were obtained with steady background fields at mesopic and photopic light levels (i.e., 0.06-110 cd/m2) for retinal eccentricities from 0° to 15° using three combinations of background/test field sizes (i.e., 10°/2°, 10°/0.45°, and 1°/0.45°). A two-channel Maxwellian view optical system was employed to eliminate pupil effects on the measured thresholds. A model based on visual mechanisms that were described in the literature was optimized to fit the measured luminance thresholds in all experimental conditions. Our results can be described by a combination of visual mechanisms. We determined how spatial summation changed with eccentricity and how subtractive adaptation changed with eccentricity and background field size. According to our model, photon noise plays a significant role to explain contrast detection thresholds measured with the 1/0.45° background/test size combination at mesopic luminances and at off-axis eccentricities. In these conditions, our data reflect the presence of rod-cone interaction for eccentricities between 6° and 9° and luminances between 0.6 and 5 cd/m2. In spite of the increasing noise effects with eccentricity, results also show that the visual system tends to maintain a constant signal-to-noise ratio in the off-axis detection task over the whole mesopic range.

Semisimple varieties of implication zroupoids Cornejo, Juan Manuel; Sankappanavar, Hanamantagouda P. It is a well known fact that Boolean algebras can be defined using only implication and a constant. In fact, in 1934, Bernstein (Trans Am Math Soc 36:876–884, 1934) gave a system of axioms for Boolean algebras in terms of implication only. Though his original axioms were not equational, a quick look at his axioms would reveal that if one adds a constant, then it is not hard to translate his system of axioms into an equational one. Recently, in 2012, the second author of this paper extended this modified Bernstein’s theorem to De Morgan algebras (see Sankappanavar, Sci Math Jpn 75(1):21–50, 2012). Indeed, it is shown in Sankappanavar (Sci Math Jpn 75(1):21–50, 2012) that the varieties of De Morgan algebras, Kleene algebras, and Boolean algebras are term-equivalent, respectively, to the varieties, DM, KL, and BA whose defining axioms use only the implication → and the constant 0. The fact that the identity, herein called (I), occurs as one of the two axioms in the definition of each of the varieties DM, KL and BA motivated the second author of this paper to introduce, and investigate, the variety I of implication zroupoids, generalizing De Morgan algebras. These investigations are continued by the authors of the present paper in Cornejo and Sankappanavar (Implication zroupoids I, 2015), wherein several new subvarieties of I are introduced and their relationships with each other and with the varieties studied in Sankappanavar (Sci Math Jpn 75(1):21–50, 2012) are explored. The present paper is a continuation of Sankappanavar (Sci Math Jpn 75(1):21–50, 2012) and Cornejo and Sankappanavar (Implication zroupoids I, 2015). The main purpose of this paper is to determine the simple algebras in I. It is shown that there are exactly five (nontrivial) simple algebras in I. From this description we deduce that the semisimple subvarieties of I are precisely the subvarieties of the variety generated by these simple I-zroupoids and that they are locally finite. It also follows that the lattice of semisimple subvarieties of I is isomorphic to the direct product of a 4-element Boolean lattice and a 4-element chain.

An empirical comparison of feature selection methods in problem transformation multi-label classification Rodriguez, Juan Manuel; Godoy, Daniela Lis; Zunino Suarez, Alejandro Octavio Multi-label classification (MLC) is a supervised learning problem in which a particular example can be associated with a set of labels instead of a single one as in traditional classification. Many real-world applications, such as Web page classification or resource tagging on the Social Web, are challenging for existing MLC algorithms, because the label space grows exponentially as instance space increases. Under the problem transformation approach, the most common alternative for MLC, multi-label problems are transformed into several single label problems, whose outputs are then aggregated into a prediction to the whole classification problem. Feature selection techniques become crucial in large-scale MLC problems to help reducing dimensionality. However, the impact of feature selection in multi-label setting has not been as extensively studied as in the case of single-label data. In this paper, we present an empirical evaluation of feature selection techniques in the context of the three main problem transformation MLC methods: Binary Relevance, Pair-wise and Label power-set. Experimentation was performed across a number of benchmark datasets for multi-label classification exhibiting varied characteristics, which allows observing the behavior of techniques and assessing their impact according to multiple metrics.

“La Natura que cría todas las crïaturas”: una nota sobre la figura de Naturaleza en el Libro de Alexandre; "La Natura que cría todas las crïaturas": A Note on the Figure of Nature in the Libro de Alexandre Fuentes, Juan Héctor Las estrofas 2324-2333 del Libro de Alexandre nos ofrecen una traducción, o mejor, una adaptación de los versos 6-30 del libro 10 del Alexandreis de Gautier de Châtillon, en los que se nos presenta a Natura, personificación de la naturaleza, encolerizada por la soberbia de Alejandro. En el presente trabajo estudiamos el tratamiento del personaje que presenta el libro castellano en relación con su modelo latino y con el concepto de "naturaleza" elaborado por los autores del "Renacimiento del siglo XII".; Stanzas 2324-2333 of Libro de Alexandre offer a translation, or rather, an adaptation of verses 6-30, Book 10, of Gautier de Châtillon’s Alexandreis, in which Natura is presented as a personification of nature, angry at the pride of Alexander. In this paper we study the treatment of this character present in the Castilian poem in relation to its Latin model and the concept of "nature" developed by the authors of the 12th-Century Renaissance.

Microplate assay for the determination of carboxypeptidase A inhibitory activity in Andean potatoes Tellechea, Mariana Edith; Garcia Pardo Javier; Cotabarren, Juliana; Lufrano, Daniela; Avilés, Francesc Xavier; Obregon, Walter David; Lorenzo, Julia; Tanco, Sebastian Metallocarboxypeptidases (MCPs) are zinc-dependent exopeptidases that catalyze the hydrolysis of C-terminal amide bonds in proteins and peptides. MCPs are involved in a wide range of physiological processes and have recently emerged as relevant drug targets in biomedicine (Arolas et. al., 2007). In higher plants, small proteinaceous protease inhibitors are wound-induced molecules produced as a part of its defense system against insect attack (Graham et. al., 1981; Villanueva et. al. 1998). Among such inhibitors, only two are specific for MCPs, i.e. the potato carboxypeptidase inhibitor (PCI) and its close homologue found in tomato plants. In humans, MCP action is exquisitely regulated and dysregulation of their function might lead to disease or even to cell death (Arolas et. al., 2007). In this context, the discovery and characterization of new MCPs inhibitors constitute a valuable approach for the development of new therapeutic strategies. Over the last few decades, the presence of MCPs inhibitors in Solanaceae has been extensively reported, revealing potato (Solanum tuberosum) as one of the most important sources of MCPs inhibitors (Hass et. al.,1979; Lufrano et. al., 2015). In this context, potatos are native from the Andean region of South America, where thousands of different potato varieties coexist, constituting a natural reservoir for the discovery of novel MCP inhibitors (Figure 1). In this protocol, we describe an optimized, simple and accessible microplate method for the measure of the specific and dose-response carboxypeptidase A inhibitory activities present in Andean potatoes tubers.

Gallinetita amarilla (Poliolimnas flaviventer) en la Ciudad Autónoma de Buenos Aires, Argentina Pagano, Luis Gerardo; Chiale, Maria Cecilia La Gallinetita Amarilla o Burrito Amarillo (Poliolimnas flaviventer) muestra una distribución discontinua en gran parte de Centroamérica, Antillas y Sudamérica. El 7 de noviembre de 2015, a las 13:30 h, observamos una Gallinetita Amarilla en la Laguna de Los Coipos (34°36'16"S, 58°21'36"O), Reserva Ecológica Costanera Sur (RECS), Ciudad Autónoma de Buenos Aires. Esta Gallinetita no fue mencionada previamente para la RECS (Babarskas & Zelaya 1994, Pugnali & Chamorro 2006). Si bien pudiese suponerse la presencia de esta especie en la RECS como un único individuo extra-limital o divagante, creemos que al igual que otros pequeños Rallidae pampeanos, se trata de una especie subobservada y quizá frecuente, tal como lo demuestra el hallazgo de cuatro ejemplares capturados por Halcones Peregrinos (Falco peregrinus) en un periodo de 181 días de muestreo en la ciudad de La Plata.

Wolves (Canis lupus) and dogs (Canis familiaris) differ in following human gaze into distant space but respond similar to their packmates' gaze Werhahn, Geraldine; Virányi, Zsófia; Barrera, Gabriela Luciana; Sommese, Andrea; Range, Friederike Gaze following into distant space is defined as visual co-orientation with another individual's head direction allowing the gaze follower to gain information on its environment. Human and nonhuman animals share this basic gaze following behavior, suggested to rely on a simple reflexive mechanism and believed to be an important prerequisite for complex forms of social cognition. Pet dogs differ from other species in that they follow only communicative human gaze clearly addressed to them. However, in an earlier experiment we showed that wolves follow human gaze into distant space. Here we set out to investigate whether domestication has affected gaze following in dogs by comparing pack-living dogs and wolves raised and kept under the same conditions. In Study 1 we found that in contrast to the wolves, these dogs did not follow minimally communicative human gaze into distant space in the same test paradigm. In the observational Study 2 we found that pack-living dogs and wolves, similarly vigilant to environmental stimuli, follow the spontaneous gaze of their conspecifics similarly often. Our findings suggest that domestication did not affect the gaze following ability of dogs itself. The results raise hypotheses about which other dog skills might have been altered through domestication that may have influenced their performance in Study 1. Because following human gaze in dogs might be influenced by special evolutionary as well as developmental adaptations to interactions with humans, we suggest that comparing dogs to other animal species might be more informative when done in intraspecific social contexts.

A new and consistent parameter for measuring the quality of multivariate analytical methods: Generalized analytical sensitivity Fragoso, Wallace; Allegrini, Franco; Olivieri, Alejandro Cesar Generalized analytical sensitivity (γ) is proposed as a new figure of merit, which can be estimated from a multivariate calibration data set. It can be confidently applied to compare different calibration methodologies, and helps to solve literature inconsistencies on the relationship between classical sensitivity and prediction error. In contrast to the classical plain sensitivity, γ incorporates the noise properties in its definition, and its inverse is well correlated with root mean square errors of prediction in the presence of general noise structures. The proposal is supported by studying simulated and experimental first-order multivariate calibration systems with various models, namely multiple linear regression, principal component regression (PCR) and maximum likelihood PCR (MLPCR). The simulations included instrumental noise of different types: independently and identically distributed (iid), correlated (pink) and proportional noise, while the experimental data carried noise which is clearly non-iid.

Affecting factors and recent improvements of the photochemical reflectance index (pri) for remotely sensing foliar, canopy and ecosystemic radiation-use efficiencies Zhang, Chao; Filella, Iolanda; Garbulsky, Martín Fabio; Peñuelas, Josep Accurately assessing terrestrial gross primary productivity (GPP) is crucial for characterizing the climate-carbon cycle. Remotely sensing the photochemical reflectance index (PRI) across vegetation functional types and spatiotemporal scales has received increasing attention for monitoring photosynthetic performance and simulating GPP over the last two decades. The factors confounding PRI variation, especially on long timescales, however, require the improvement of PRI understanding to generalize its use for estimating carbon uptake. In this review, we summarize the most recent publications that have reported the factors affecting PRI variation across diurnal and seasonal scales at foliar, canopy and ecosystemic levels; synthesize the reported correlations between PRI and ecophysiological variables, particularly with radiation-use efficiency (RUE) and net carbon uptake; and analyze the improvements in PRI implementation. Long-term variation of PRI could be attributed to changes in the size of constitutive pigment pools instead of xanthophyll de-epoxidation, which controls the facultative short-term changes in PRI. Structural changes at canopy and ecosystemic levels can also affect PRI variation. Our review of the scientific literature on PRI suggests that PRI is a good proxy of photosynthetic efficiency at different spatial and temporal scales. Correcting PRI by decreasing the influence of physical or physiological factors on PRI greatly strengthens the relationships between PRI and RUE and GPP. Combining PRI with solar-induced fluorescence (SIF) and optical indices for green biomass offers additional prospects.

Galaxy clusters, type Ia supernovae and the fine structure constant Holanda, R. F. L.; Busti, V. C.; Colaco, R. L.; Alcaniz, J. S.; Landau, Susana Judith As is well known, measurements of the Sunyaev-Zeldovich effect can be combined with observations of the X-ray surface brightness of galaxy clusters to estimate the angular diameter distance to these structures. In this paper, we show that this technique depends on the fine structure constant, α. Therefore, if α is a time-dependent quantity, e.g., α = α0φ(z), where φ is a function of redshift, we argue that current data do not provide the real angular diameter distance, DA(z), to the cluster, but instead DA data(z) = φ(z)2 DA(z). We use this result to derive constraints on a possible variation of α for a class of dilaton runaway models considering a sample of 25 measurements of DA data(z) in redshift range 0.023 < z < 0.784 and estimates of DA(z) from current type Ia supernovae observations. We find no significant indication of variation of α with the present data.

Drosophila melanogaster, an emerging animal model for the study of human cardiac diseases; Drosophila melanogaster, un modelo animal emergente en el estudio de enfermedades cardíacas humanas Santalla, Manuela; Portiansky, Enrique Leo; Ferrero, Paola Viviana The need to work with model organisms in medical research has revealed the usefulness of the fruit fly Drosophila melanogaster, considering its advantages to perform classic genetic studies and modern techniques of genome edition. Several human genes are similar to those of the fruit fly. We have developed for the first time in the country a cardiovascular line of research to study the genetics of aging, addictions and chronic consumption of substances in humans like caffeine.; La necesidad de trabajar con modelos de organismos en la investigación sobre salud ha revelado las utilidades de la mosca de la fruta Drosophila melanogaster considerando sus ventajas para realizar genética clásica y modernas técnicas de edición del genoma. Muchos genes humanos son homólogos a los genes de la mosca. Hemos desarrollado por primera vez en el país una línea de investigación cardiovascular para estudiar la genética del envejecimiento, las adicciones y sustancias de consumo crónico en el humano como la cafeína.

Genome analysis of a clinical isolate of Shewanella sp. uncovered an active hybrid integrative and conjugative element carrying an integron platform inserted in a novel genomic locus Parmeciano Di Noto, Gisela Paula; Jara, Eugenio; Iriarte Odini, Andrés; Centron, Daniela; Quiroga, Cecilia Shewanella spp. are currently considered emerging pathogens that can code for a blaOXA carbapenemase in their chromosome. Complete genome analysis of the clinical isolate Shewanella sp. Sh95 revealed that this strain is a novel species that shares a lineage with marine isolates. Characterization of its resistome showed that it codes for genes drfA15, qacH and blaOXA-48. We propose that Shewanella sp. Sh95 acts as reservoir of blaOXA-48. Moreover, mobilome analysis showed that it contains a novel ICE, named ICESh95. Comparative analysis between the close relatives ICESpuPO1 from Shewanella sp. W3-18-1 and ICE SXTMO10 from Vibrio cholerae showed that ICESh95 encompassed two new regions, a type III restriction modification system and a multidrug resistance integron. The integron platform contained a novel arrangement formed by gene cassettes drfA15 and qacH and a class C-attC group II intron. Furthermore, insertion of ICESh95 occurred at a unique target site, which correlates with the presence of a different xis/int module. Mobility of ICESh95 was assessed showing its ability to self-transfer at high levels to different bacteria species. The presence of a highly adaptable element capable of acquiring antibiotic resistance determinants, combined with its efficient activity to self-transfer makes this element a clear threat for the control of the dissemination of antimicrobial resistance; a troublesome scenario when natural bacteria from water ecosystems, such as Shewanella, act as vector in its propagation.

Fossil snake preserving three trophic levels and evidence for an ontogenetic dietary shift Smith, Krister; Scanferla, Carlos Agustín We report a fossil snake from the middle Eocene (48 Ma) Messel Pit, in whose stomach is a lizard, in whose stomach is an insect. This is the second known vertebrate fossil containing direct evidence of three trophic levels. The snake is identified as a juvenile of Palaeopython fischeri on the basis of new characters of the skull; the lizard is identified as Geiseltaliellus maarius, a stem-basilisk; and the insect, despite preserved structural colouration, could not be identified more precisely. G. maarius is thought to have been an arboreal species, but like its extant relatives may have foraged occasionally on the ground. Another, larger specimen of G. maarius preserves plant remains in the digestive tract, suggesting that omnivory in this species may have been common in larger individuals, as in extant Basiliscus and Polychrus. A general picture of the trophic ecology of P. fischeri is not yet possible, although the presence of a lizard in the stomach of a juvenile individual suggests that this snake could have undergone a dietary shift, as in many extant boines.

The effects of land management (grazing intensity) vs. the effects of topography, soil properties, vegetation type, and climate on soil carbon concentration in Southern Patagonia Peri, Pablo Luis; Ladd, B.; Lasagno, R. G.; Martínez Pastur, Guillermo José Grazing is an economically important activity in Southern Patagonia?s steppe and woodland ecosystems. In the past, emphasis has been on maximizing the provisioning capacity of these ecosystems with little concern for the longer term conservation of the ecosystem services related to climate regulation, likecarbon sequestration. This is changing rapidly as livestock producers in the region work to develop a certification scheme for sustainable land management for Patagonians rangelands. This study is a scientific contribution towards this broader social objective in which we test whether soil C concentrationin topsoil (10 cm depth) can be used as an indicator of rangeland condition. Data on climate, soil chemistry, topography, ecosystem type and stocking rates were obtained from the PEBANPA network of permanent plots database for 145 sites across Southern Patagonia. These variables were used as independent variables in a partial least squares regression in which top soil C was the dependent variable. The effects of land use (stocking rate) on top soil C were barely detectable at the regional scale in Patagonia. Top soil C was however strongly associated with other independent variables, notably soil chemistry and climate variables and also vegetation type. Thus, changes in land use management may not have a significant impact on soil carbon sequestration in these types of ecosystems. This may be because many factors interact to determine top soil C such that the footprint of overgrazing on top soil C is drowned out at the regional scale by other variables. This highlights the need for further work todevelop indicators for sustainable land management in the region.

Essential function of the transcription factor Rax in the early patterning of the mammalian hypothalamus Orquera, Daniela Paula; Nasif, Sofia; Low, Malcolm J.; Rubinstein, Marcelo; Silva Junqueira de Souza, Flavio The hypothalamus is a region of the anterior forebrain that controls basic aspects of vertebrate physiology, but the genes involved in its development are still poorly understood. Here, we investigate the function of the homeobox gene Rax/Rx in early hypothalamic development using a conditional targeted inactivation strategy in the mouse. We found that lack of Rax expression prior to embryonic day 8.5 (E8.5) caused a general underdevelopment of the hypothalamic neuroepithelium, while inactivation at later timepoints had little effect. The early absence of Rax impaired neurogenesis and prevented the expression of molecular markers of the dorsomedial hypothalamus, including neuropeptides Proopiomelanocortin and Somatostatin. Interestingly, the expression domains of genes expressed in the ventromedial hypothalamus and infundibulum invaded dorsal hypothalamic territory, showing that Rax is needed for the proper dorsoventral patterning of the developing medial hypothalamus. The phenotypes caused by the early loss of Rax are similar to those of eliminating the expression of the morphogen Sonic hedgehog (Shh) specifically from the hypothalamus. Consistent with this similarity in phenotypes, we observed that Shh and Rax are coexpressed in the rostral forebrain at late head fold stages and that loss of Rax caused a downregulation of Shh expression in the dorsomedial portion of the hypothalamus.

El trabajo asalariado agropecuario en la región yerbatera argentina. Imágenes de situación en datos cuantitativos; The farmwork in the yerba mate region from Argentina. Images of situation in quantitative data Rau, Victor Horacio El estudio describe la situación estructural de los trabajadores agropecuarios en la región argentina productora de yerba mate, dando cuenta de sus distribuciones territoriales, sus ámbitos de residencia,las estructuras socioproductivas en que se insertan, y de sus condiciones de vida y empleo en diferentes contextos. Se basa en el análisis de datos cuantitativos provenientes de diversas fuentes. Caracteriza ala región yerbatera en el contexto nacional y del NEA, y describe sus heterogeneidades internas.Advierte sobre la importancia que conserva la residencia rural, el vínculo de la pobreza con el trabajo agropecuario, y de la informalidad con la transitoriedad del empleo.; The study describes the structural situation of farmworkers in argentine region producer of yerba mate, indicating their territorial distribution, their areas of residence, the socio-productive structures in which are inserted, and their conditions of life and employment in different contexts. It is based on the analysis of quantitative data from different sources. It characterizes the yerba mate region in the national context and the NEA, and describes their internal heterogeneities. It warns about the importance that preserves the rural residence, the link poverty with farmwork, and the informality with the seasonal employment.