Transcriptional characterization of wnt and notch signaling pathways in neuronal differentiation of human adipose tissue-derived stem cells Cardozo, Alejandra Johana; Gomez, Daniel Eduardo; Argibay, Pablo Francisco Since the nervous system has limited self-repair capability, a great interest in using stem cells is generated to repair it. The adipose tissue is an abundant source of stem cells and previous reports have shown the differentiation of them in neuron-like cells when cultures are enriched with growth factors involved in neurogenesis. Regarding this, it could be thought that a functional parallelismbetween neurogenesis and neuronal differentiation of human adipose stem cells (hASCs) exists. For this reason, we investigated the putative involvement ofNotch and Wnt pathways in neuronal differentiation of hASCs through real-time PCR. We found that both Wnt and Notch signaling are present in proliferating hASCs and that both cascades are downregulated when cells are differentiated to a neuronal phenotype. These results are in concordance with previous works where it was found that both pathways are involved in the maintenance of the proliferative state of stem cells, probably through inhibition of the expression of cell-fatespecific genes. These results could support the notion that hASCs differentiation into neuron-like cells represents a regulated process analogous to what occurs during neuronal differentiation of NSCs and could partially contribute to elucidate the molecular mechanisms involved in neuronal differentiation of adult human nonneural tissues.

Effect of the arbuscular mycorrhizal fungus Glomus intraradices on the false root-knot nematode Nacobbus aberrans in tomato plants Lax, Paola; Becerra, Alejandra Gabriela; Soteras, María Florencia; Cabello, Marta Noemí; Doucet, Marcelo Edmundo Information about the interaction between arbuscular mycorrhizal fungi (AMF) and the false root-knot nematode Nacobbus aberrans (Thorne, 1935) Thorne & Allen, 1944 is scarce. The effect of Glomus intraradices Schenk & Smith on tomato (Lycopersicon esculentum L.) cv. Platense inoculated with nematode juveniles from Lisandro Olmos (Argentina) was studied under greenhouse conditions. Six treatments with five replications were performed. After 80 days, nematode reproduction and percentage of AMF colonization in roots were estimated. Some plant growth parameters were also measured. In general, plants with AMF and AMF plus nematodes grew as well as the control without AMF and without nematodes. Furthermore, G. intraradices was beneficial in reducing nematode-induced damage in roots (lower number of galls) as well as in having a suppressive effect on parasite reproduction. This is the first study on the use of G. intraradices as a possible strategy in the control of N. aberrans in tomato.

The segmentation of the argentine education system: evidence from PISA 2009 Krüger, Natalia Soledad For decades, one of the main goals for policy makers throughout the world has been to provide equal educational opportunities. Nevertheless, many countries still face great challenges in this respect, especially considering equality in the distribution of resources. Since the early eighties, Argentina has focused the fact that the education system is segmented, i.e., divided into groups of institutions of differential quality in which students are distributed according to their socio-economic background. This means that schooling reproduces and reinforces existing patterns of social inequality. The purpose of this article is to contribute to the comprehension and the diagnosis of the current relevance of this phenomenon. Based on information from the PISA 2009 survey, the aim is to establish the degree of educational segmentation, evaluating the distribution of the schools physical, human, and social capitals, as well as the interaction of these resources with student characteristics. A cluster analysis is performed for visualising how these factors lead to the configuration of different school profiles. This may be a useful tool to assist in designing strategies to level the most disadvantaged schools, thus better mediating the impact of socio-economic background on educational success.

Growth and Development in Wild Owl Monkeys (Aotus azarai) of Argentina Huck, Marcos Andrés; Rotundo, Marcelo; Fernandez Duque, Eduardo Life history predicts that in sexually dimorphic species in which males are the larger sex, males should reach sexual maturity later than females (or vice versa if females are the larger sex). The corresponding prediction that in sexually monomorphic species maturational rates will differ little between the sexes has rarely been tested. We report here sex differences in growth and development to adulthood for 70 female and 69 male wild owl monkeys (Aotus azarai). In addition, using evidence from natal dispersal and first reproduction (mean: 74 mo) for 7 individuals of known age, we assigned ages to categories: infant, 0–6 mo; juvenile, 6.1–24 mo; subadult, 24.1–48 mo; adult >48 mo. We compared von Bertalanffy growth curves and growth rates derived from linear piecewise regressions for juvenile and subadult females and males. Growth rates did not differ between the sexes, although juvenile females were slightly longer than males. Females reached maximum maxillary canine height at ca. 2 yr, about a year earlier than males, and females’ maxillary canines were shorter than males’. Thus apart from canine eruption and possibly crown–rump length, the development of Azara’s owl monkeys conforms to the prediction by life history that in monomorphic species the sexes should develop at similar paces.

The influence of spectral power distribution on contrast sensitivity Arranz, Isabel; Matesanz, Beatriz; de la Rosa, Cristina; Menéndez, José; Issolio, Luis Alberto; Mar, Santiago; Aparicio, Juan Antonio The influence of lighting of different spectral power distribution on letter contrast sensitivity has been studied. The different spectral power distributions were obtained by filtering or dimming tungsten halogen lamps. Measurements were made on 20 young and healthy individuals (25 eyes) whose monocular contrast sensitivities were measured with a natural pupil. Sixteen combinations of test and surround luminance with high or low correlated colour temperatures were studied in such a way that the influence of test luminance, surround luminance or colour temperature of both visual fields could be independently studied. Both test luminance and surround luminance influenced contrast sensitivity but correlated colour temperature did not.

Influencia del nivel de almidón y celulosa en la dieta sobre el perfil metabólico y digestibilidad aparente en camarones penaeoideos; Influence of dietary starch and cellulose levels on the metabolic profile and apparent digestibility in penaeoid shrimp Velurtas, Susana María; Díaz, Ana Cristina; Fernandez Gimenez, Analia Veronica; Fenucci, Jorge Lino En el presente estudio se comparó el efecto de diferentes concentraciones de almidón/celulosa (30/0; 20/10; 10/20; 0/30) sobre la respuesta metabólica y la digestibilidad aparente en dos especies de peneidos, Artemesia longinaris y Pleoticus muelleri. Se utilizaron animales adultos a fin de obtener cantidades suficientes de hemolinfa y heces para los análisis. No hubo diferencias significativas en los niveles de metabolitos plasmáticos en P. muelleri, en cambio en A. longinaris se observó un incremento significativo de la glucosa, proteínas totales y colesterol en relación con el aumento del almidón en la dieta. Los coeficientes de digestibilidad aparente disminuyeron de 83,7% a 51,2% (A. longinaris) y de 71,9% a 7,6% (P. muelleri) a medida que los porcentajes de almidón en la dieta aumentaron. El cociente entre la actividad de amilasa y proteasa (A/P) se redujo en A. longinaris con los mayores porcentajes de almidón dietario; por el contrario, el cociente A/P en P. muelleri aumentó cuando la concentración fue más alta. Estos resultados demostraron que existe una estrecha relación entre los hábitos alimentarios y la fisiología digestiva de las dos especies estudiadas; sugiriendo un comportamiento más herbívoro para A. longinaris y más omnívoro para P. muelleri.; The present study compared the effect of different starch/cellulose ratios (30/0, 20/10, 10/20, 0/30) on the metabolic response and apparent digestibility in two species of penaeoids: Artemesia longinaris and Pleoticus muelleri. Adult animals were used in order to obtain sufficient quantities of haemolymph and faecal material for analysis. No significant differences were found in levels of plasma metabolites in P. muelleri, but in A. longinaris, a significant increase was observed in glucose, total protein, and cholesterol in correlation with increased dietary starch. The apparent digestibility coefficients decreased from 83.7% to 51.2% (A. longinaris) and from 71.9% to 7.6% (P. muelleri) as the dietary starch levels increased. The ratio of amylase activity to protease activity (A/P ratio) declined in A. longinaris when the percentage of dietary starch increased. In contrast, the A/P ratio for P. muelleri increased with higher starch concentrations. These results demonstrated a close relationship between the feeding habits and digestive physiology of the two species studied; they also suggest a more herbivorous behavior for A. longinaris and more omnivorous habits for P. muelleri.

Modern embalming, circulation of fluids, and the voyage through the human arterial system: Carl L. Barnes and the culture of immortality in America Podgorny, Irina By considering the work of American embalmer, lawyer, and physician Carl Lewis Barnes (1872-1927), this paper analyzes the emergence of modern embalming in America. Barnes experimented with and exhibited the techniques by which embalming fluids travelled into the most remote cavities of the human body. In this sense, modern embalmers based their skills and methods on experimental medicine, turning the anatomy of blood vessels, physiology of circulation, and composition of blood into a circuit that allowed embalming fluids to move throughout the corpse. Embalmers in the late 19th century took ownership of the laws of hydrodynamics and the physiology of blood circulation to market their fluids and equipment, thus playing the role of physiologists of death, performing and demonstrating physiological experiments with dead bodies.

Entropic upper bound on gravitational binding energy Vignat, C.; Plastino, Ángel Luis; Plastino, Ángel Ricardo We prove that the gravitational binding energy Ω of a self gravitating system described by a mass density distribution ρ(x) admits an upper bound B[ρ(x)] given by a simple function of an appropriate, non-additive Tsallis' power-law entropic functional Sq evaluated on the density ρ. The density distributions that saturate the entropic bound have the form of isotropic q-Gaussian distributions. These maximizer distributions correspond to the Plummer density profile, well-known in astrophysics. A heuristic scaling argument is advanced suggesting that the entropic bound B[ρ(x)] is unique, in the sense that it is unlikely that exhaustive entropic upper bounds not based on the alluded Sq entropic measure exit. The present findings provide a new link between the physics of self gravitating systems, on one hand, and the statistical formalism associated with non-additive, power-law entropic measures, on the other hand. © 2011 Elsevier B.V. All rights reserved.

Fomitopsis minutispora Rajchenb., a new record of Polyporales for the Chilean mycobiota; Fomitopsis minutispora Rajchenb., nuevo registro de Polyporales para la micobiota Chilena Sandoval, Pablo; Rajchenberg, Mario Se registra Fomitopsis minutispora Rajchenb. (Polyporales, Basidiomycota) por primera vez en Chile. Los basidiomas de la especie fueron hallados sobre troncos caídos, siempre en bosques con presencia del género Nothofagus en la Región de los Ríos. Se presenta una breve descripción, fotografías de la especie y una clave para diferenciar los políporos de basidiomas perennes y pileados más comunes en los bosques de Nothofagus de Chile.

Spectroelectrochemical evidence for the nitrosyl redox siblings NO +, NO., and NO- coordinated to a strongly electron-accepting FeII porphyrin: DFT calculations suggest the presence of high-spin states after reduction of the FeII-NO - complex Pellegrino, Juan; Hübner, Ralph; Doctorovich, Fabio; Kaim, Wolfgang Experimental and computational results for the electron-deficient porphyrin complex [Fe(NO)(TFPPBr8)] (1; TFPPBr8=2,3,7,8,12,13,17, 18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) are reported with respect to its electron-transfer behavior. Complex 1 undergoes three one-electron processes: two reversible reductions and one irreversible oxidation. Spectroelectrochemical measurements (IR and UV/Vis/NIR spectroscopy) of 14NO- and 15NO-containing material indicate that the first reduction to 1- occurs largely on the NO ligand to produce nitroxyl anion (NO-) character, as evident from the considerable change in νNO from 1715 to around 1550 cm-1. The second reduction to 12- does not result in a further shift of νNO to lower frequencies, but to a surprising high-energy shift to 1590 cm-1. This and the notable changes of the characteristic porphyrin vibrations as well as significant changes of the UV/Vis absorptions indicate a porphyrin-centered process; DFT calculations predict the shift of νNO to higher frequencies for the intermediate- and high-spin states of 12-. The oxidation of 1 is irreversible on the voltammetry timescale, but chemically reversible in spectroelectrochemical experiments, suggesting that the cationic form dissociates to the corresponding ferric porphyrin and NO. DFT calculations support the interpretation of the experimental results. En este trabajo se estudia el comportamiento redox del complejo {FeNO}7 con sustituyentes atractores de electrones, [Fe(NO)(TFPPBr8)]=1 (TFPPBr8=2,3,7,8,12,13,17,18- octabromo-5,10,15,20-tetrakis(pentafluorofenil)porfirina) mediante experimentos de espectroelectroquímica y cálculos computacionales. El complejo 1 presenta tres procesos electroquímicos de un electrõn: dos reducciones reversibles y una oxidaciõn irreversible. El considerable cambio de νNO de 1715 cm-1 a ≈ 1550 cm-1 indica que la primera reducciõn a 1- involucra en gran medida al ligando NO. Para la segunda reducciõn a 12- se observa, sorprendentemente, un cambio de νNO a ≈ 1590 cm-1. Este pequeño corrimiento de νNO y los cambios notables de las vibraciones asociadas a modos de la porfirina, así como los cambios significativos en la banda UV/Vis de Soret, indican un proceso centrado en la porfirina; los cálculos DFT predicen el corrimiento de νNO a mayores frecuencias para los estados de spin intermedio y alto de 1 2-. En cuanto a la oxidaciõn de 1, la onda irreversible en la voltametría cíclica sugiere que la forma catiõnica 1 + se disocia dando la porfirina de hierro(III) y NO; sin embargo, en el experimento espectroelectroquímico el proceso resulta reversible, recuperándose la νNO de 1 al reducir. Los cálculos DFT apoyan la interpretaciõn de los resultados experimentales. All in a spin: IR and UV/Vis spectroelectrochemistry reveal that the oxidation and the first reduction of [Fe(NO)(TFPPBr8)] (TFPPBr8= 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetrakis(pentafluorophenyl)porphyrin) mainly affect the FeNO moiety. In the two-electron-reduced form, the added electrons appear mainly located on the porphyrin, and DFT calculations suggest an intermediate- or high-spin state (see figure).

The use of actometry and electronic nose devices to assess the locomotor activity of two species of Coccinellidae (Coleoptera) Heit, Guillermo Eugenio; Messina, Valeria Marisa; Mareggiani, Graciela Silvia; Cohen, Rosa Graciela; Carrizo, Paola The effect of odor signals on the locomotor activity of Cycloneda sanguinea and Harmonia axyridis was evaluated using two different actometric devices. The purpose of the analysis was to differentiate between the responses elicited by direct contact with the substrates and the responses that occurred if the coccinellids were exposed only to volatiles and had no direct substrate contact. The odor profile of the environmental volatiles (semiochemicals) in the bioassays was analyzed using an electronic nose (Modular Sensor System Moses II). The treatments used included volatiles emitted by pepper leaves (healthy or infested with Myzus persicae), M. persicae molts and honeydew, and healthy leaves treated with an artificial inducer of the systemic acquired response to herbivory (AISAR). The results suggest that a specific stimulus linked to aphid-host interaction would trigger a distinctive locomotor activity pattern in H. axyridis, with or without any contact with the aphids or the host plant. In contrast, C. sanguinea was not able to differentiate between volatiles from infested or uninfected pepper leaves or to distinguish these volatiles from clean filter paper (control). If C. sanguinea was in contact with aphid-infested pepper leaves (regardless of the previous prey density), it moved slowly and scanned the area exhaustively; H. axyridis showed significantly reduced locomotor activity when it was in contact with aphid-infested pepper leaves or aphid molts and honeydew, all reliable signals of the presence of a food source. In both species, treatment with Actigard (AISAR: Acibenzolar-S-methyl) failed to evoke the behavioral response observed in the treatment with aphid-infested pepper plants. The study also demonstrated that the E-nose can differentiate among blends of volatiles released from cut healthy or aphid-infested pepper leaves.

Performance of a multipurpose research electrochemical reactor Henquín, Eduardo Rubén; Bisang, Jose Maria This paper reports on a multipurpose research electrochemical reactor with an innovative design feature, which is based on a filter press arrangement with inclined segmented electrodes and under a modular assembly. Under bipolar connection, the fraction of leakage current is lower than 4%, depending on the bipolar Wagner number, and the current distribution is closely uniform. When a turbulence promoter is used, the local mass-transfer coefficient shows a variation of ±10% with respect to its mean value. The fluidodynamics of the reactor responds to the dispersion model with a Peclet number higher than 10. It is concluded that this reactor is convenient for laboratory research.

Fossil cocoons associated with a dinosaur egg from Patagonia, Argentina Genise, Jorge Fernando; Sarzetti, Laura Cristina Eight fossil (Cretaceous) insect cocoons were discovered within the infillings of a broken dinosaur egg of a clutch from a Patagonian locality. Cocoons are considered to be in situ based on detailed preservation of thin, delicate walls with surface texture, infillings that are similar to the surrounding rock matrix and the clustered distribution of cocoons in only one egg out of the clutch of five eggs. According to the shape, size, and thin wall with surface texture, the cocoons are interpreted as having been produced by wasps. The wasps may have been attracted to the egg because of the presence of scavenging insects feeding on the decaying organic matter, or they may have been attracted to spiders feeding on the scavenging insects. In either scenario, after attacking the insects or spiders inside the sand infillings of the egg, the wasp larvae produced the cocoons described herein. The presence of wasps, which are at the top of the scavenging food webs, suggests that a complex community of invertebrates would have developed around rotten dinosaur eggs.

New materials of Argentoconodon fariasorum (Mammaliaformes, Triconodontidae) from the Jurassic of Argentina and its bearing on triconodont phylogeny Gaetano, Leandro Carlos; Rougier, Guillermo W. Argentoconodon fariasorum is the only triconodont from the Jurassic of South America. Originally described on the basis of an upper molariform, A. fariasorum is now known by several specimens, including one that preserves most of its dentition, upper and lower jaws, and several postcranial elements. Close anatomical similarity exists between Argentoconodon fariasorum, Ichthyoconodon jaworowskorum, from the Cretaceous of Morocco, and the likely Jurassic Volaticotherium antiquus, from China. The results of a phylogenetic analysis including most taxa relevant to addressing triconodont phylogenetic relationships show Argentoconodon and Volaticotherium as a clade, which in turn is more closely related to Ichthyoconodon than to any other taxon. Our most parsimonious hypotheses support a triconodontid ancestry for Argentoconodon, Ichthyoconodon, and Volaticotherium as members of the monophyletic traditional subfamily Alticonodontinae. The inclusion of Argentoconodon among alticonodontines extends the geographical and temporal distribution of this triconodont subfamily to the South American Early Jurassic, resulting in extensive ghost lineages for many triconodontid groups. Postcranial similarities between Argentoconodon and Volaticotherium make it possible that the Argentinean taxon might have had gliding capabilities; if this is the case, our cladistic analysis highlights the possible existence of a gliding clade of triconodonts of wide distribution from at least as early as the Early Jurassic.

La Tasa de miseria de los ogares. Una aproximación metodológica y conceptual a la medición, distribución espacial y variaciones de la pobreza extrema en Argentina durante la década del noventa.; Misery Rate of Homes. A methodological and conceptual approximation to measuring spatial distribution and variations of extreme poverty in Argentina during the decade of the nineties Longhi, Hugo Fernando Las brisas marinas son fenómenos meteorológicos a escala local que ejercen su influencia sobre la costa durante todo el año, sin embargo son escasos los trabajos realizados en la costa argentina. El objetivo de la presente investigación es caracterizar y determinar la ocurrencia de las brisas de mar en Monte Hermoso, balneario ubicado en el suroeste de la Provincia de Buenos Aires (61º15’55’’W, 38º59’33’’S). El periodo analizado abarca desde diciembre de 2007 a julio de 2010. Se aplicó la metodología propuesta por Zubillaga y Piccolo (1977/78a) y García y Piccolo (2004) para la identificación de la brisa marina. Se analizaron datos meteorológicos de temperatura, humedad y viento obtenidos de la estación ubicada en el balneario. Se complementó el estudio con el análisis de mapas sinópticos e imágenes satelitales. Se identificaron 40 días con brisas de mar cuya mayor frecuencia se evidenció durante el verano con 18 casos. El mes de julio no presentó brisas durante el periodo analizado. Las brisas marinas predominaron del sector ESE y SE. Su duración promedio fue de dos horas y media. La velocidad media de las brisas marinas fue 4.5 m s-1.; Les brises marines sont phénomènes météorologiques à l’échelle locale qu’ils exercent son influence sur la côte pendant toute l’année, cependant ils sont peu abondants, les travaux réalisés sur la côte argentine. L’objectif de la recherche présente est de caractériser et de déterminer la circonstance des brises de mer dans Monte Hermoso, la station balnéaire placée dans le sud-ouest de la Province du Buenos Aires (61º15‘55“W, 38º59‘3”S). La période analysée comprend du décembre 2007 à un juillet 2010. Elle s’est appliquée, la méthodologie proposée par Zubillaga et Piccolo (1977/78a) et García et Piccolo (2004) pour l’identification de la brise marine. On a analysé des données météorologiques de température, d’humidité et de vent obtenues de la station placée dans la station balnéaire. L’étude s’est complétée avec l’analyse de cartes synoptiques et d’images satelitales. Ils se sont identifiés 40 jours aux brises de mer dont la plus grande fréquence a été manifeste durant l’été avec 18 cas. Un juillet il n’a pas présenté de brises durant la période analysée. Les brises marines ont prédominé du secteur c’et. Sa durée milieu a été de deux heures et demie. La vitesse moyenne des brises marines a été 4.5 m s-1.

Funciones ejecutivas en niños escolarizados: efectos de la edad y del estrato socioeconómico; Executive functions in school-aged children: age and socioeconomic status effects Arán Filippetti, Vanessa En los últimos años, se ha incrementado notoriamente el estudio sobre las funciones ejecutivas prefrontales en niños de edad escolar. El objetivo del presente estudio es analizar la influencia de la edad y del estrato socioeconómico (ESE) en el desempeño de tareas ejecutivas y conocer cuáles son las variables socioeconómicas que predicen una mejor ejecución. Participaron 254 niños de 7 a 12 años de edad de diferentes estratos socioeconómicos de la ciudad de Santa Fe, Argentina. Se utilizó una batería de pruebas ejecutivas sensibles a la función prefrontal. Los resultados obtenidos señalan un efecto significativo de la edad y del ESE sobre las funciones ejecutivas estudiadas. Los diferentes dominios del constructo siguen una trayectoria diferente según el desarrollo y el efecto del ESE. Además, en todas las funciones ejecutivas se evidencia un patrón de funcionamiento cognitivo inferior en los niños de estrato socioeconómico bajo (ESB). Finalmente, se encontró que, de las variables incluidas en el análisis, solo el nivel educativo de la madre y las condiciones de alojamiento de la familia se asocian al funcionamiento ejecutivo de los niños. Se discuten los resultados en función de la influencia que ejerce la maduración cerebral y las variables ambientales en el funcionamiento ejecutivo.

A matter of history: effects of tourism on physiology, behaviour and breeding parameters in Magellanic Penguins (Spheniscus magellanicus) at two colonies in Argentina Villanueva, María Cecilia; Walker, Brian G.; Bertellotti, Néstor Marcelo Increasing ecotourism activity in Argentine Patagonia has led to concerns about the effects of ecotourism on wildlife populations. Penguin breeding colonies are popular tourist destinations. While some species of penguins habituate to human visits, others exhibit negative effects due to disturbance. We studied the effects of tourism on Magellanic Penguins (Spheniscus magellanicus) at San Lorenzo colony located on the Peninsula Valdes, Chubut, Argentina. We measured behavioural, physiological, and reproductive parameters in birds nesting in tourist-visited and non-visited areas. San Lorenzo has 11 years of visitation history and a low intensity of visitors (~10,000 annually). After 15 min of a simulated tourist visit, penguins in the tourist area showed fewer alternate head turns and lower plasma levels of the stress hormone corticosterone than penguins in a non-visited area. However, penguins showed similar baseline levels of corticosterone between areas as well as similar levels of integrated corticosterone expressed after an acute stressor. Penguin breeding success and chick growth were similar between areas. We compared these findings to results previously published from Punta Tombo, a colony with a longer history (+50 years) and high intensity of annual visitors (>120,000 people). Many (reproductive and behavioural parameters), but not all (physiological parameters), of our findings are similar. That a physiological difference exists may suggest that the previous history of human visitation plays an important role in the response of the birds. Thus, the continuous monitoring of tourist activity is important, as a history of visitation disturbance seems to have an effect on how birds respond to tourists.

Numerical solution and validation concerning a descriptive model of a simultaneous heat and mass transfer process Villa Saravia, Luis Tadeo; Sanziel, Maria Cristina; Bouciguez, Angélica Carmen This paper deals with the numerical solution of an initial moving boundary problem (IMBVP) arising from a simplified version of a free boundary problem (IFBVP) which was formulated in another paper, as a mathematical model of heat and moisture transfer during the bubbling stage of an immersion frying process of stick shaped natural potato. The IMBVP was solved numerically using an explicit finite difference method, immobilizing the moving boundary through the use of the well known Landau transformation. The simulation output provides the temperature and moisture profiles and the amount of free moisture lost by vaporization. The model was validated by comparing the predicted results with experimental data. A good agreement was obtained.

Biogeochemical controls on the bacterial population in the eastern Atlantic Ocean Neogi, Sucharit Basu; Koch, Boris Peter; Schmitt Kopplin, Philippe; Pohl, Christine; Kattner, Gerhard; Yamasaki, Shintaro; Lara, Ruben Jose Little is known about bacterial dynamics in the oligotrophic ocean, particularly about cultivable bacteria. We examined the abundance of total and cultivable bacteria in relation to changes in biogeochemical conditions in the eastern Atlantic Ocean with special regard to Vibrio spp., a group of bacteria that can cause diseases in human and aquatic organisms. Surface, deep water and plankton (<20 µm, 20– 55 µm and >55 µm) samples were collected between 50◦ N and 24◦ S. Chlorophyll-a was very low (<0.3 µg l−1 ) in most areas of the nutrient-poor Atlantic, except at a few locations near upwelling regions. In surface water, dissolved organic carbon (DOC) and nitrogen (DON) concentrations were 64– 95 µM C and 2–10 µM N accounting for ≥90 % and ≥76 % of total organic C and N, respectively. DOC and DON gradually decreased to ∼45 µM C and <5 µM N in the bottom water. In the surface layer, culture independent total bacteria and other prokaryotes represented by 40 -6-diamidino- 2-phenylindole (DAPI) counts, ranged mostly between 107 and 108 cells l−1 , while cultivable bacterial counts (CBC) and Vibrio spp. were found at concentrations of 104–107 and 102–105 colony forming units (CFU) l−1 , respectively. Most bacteria (>99 %) were found in the nanoplankton fraction (<20 µm), however, bacterial abundance did not correlate with suspended particulates (chlorophyll-a, particulate organic C [POC] and N [PON]). Instead, we found a highly significant correlation between bacterial abundance and temperature (p < 0.001) and a significant correlation with DOC and DON (p < 0.005 and < 0.01, respectively). In comparison to CBC and DAPI-stained prokaryotes, cultivable Vibrio showed a stronger and highly significant correlation with DOC and DON (p < 0.0005 and p < 0.005, respectively). In cold waters of the mesopelagic and abyssal zones, CBC was 50 to 100-times lower than in the surface layer; however, cultivable Vibrio spp. could be isolated from the bathypelagic zone and even near the seafloor (average ∼10 CFU l−1 ). The depth-wise decrease in CBC and Vibrio coincided with the decrease in both DOC and POC. Our study indicates that Vibrio and other bacteria may largely depend on dissolved organic matter to survive in nutrient-poor oceanic habitats.

Producción y ambiente: beneficios mutuos Jobbagy Gampel, Esteban Gabriel; Mercau, Jorge L.; Baldi, Germán La conexión y los posibles conflictos que existen entre producir y proteger el ambiente no son una novedad para los productores agropecuarios. Reducir la erosión, sostener los niveles de materia orgánica del suelo o mantener especies valiosas del pastizal son metas presentes desde hace décadas y que han obligado a resolver dilemas entre rentabilidad inmediata y ambiente; disyuntivas que cuando se materializan en nuestro lote agregan el enorme incentivo de proteger un recurso propio. Pero la relación producción-ambiente se torna compleja y polémica cuando miramos más allá y comprendemos el papel que desempeña la porción de territorio que manejamos sobre la generación de productos y de valores ambientales que reclama la sociedad.