Cambios en la interacción de depredación entre la gaviota cocinera (Larus dominicanus) y los gaviotines real (thalasseus maximus) y pico amarillo (thalasseus sandvicensis euygnathus) en Punta León, Argentina; Changes in the predator-prey interaction between the Kelp Gull (Larus dominicanus) and Royal (Thalasseus maximus) and Cayenne terns (Thalasseus sandvicensis euygnathus) in Punta León, Argentina
Silva, Laura Alejandra; Gatto, Alejandro Javier; García, Germán Oscar; Yorio, Pablo Martin
Se estudió la depredación por parte de la Gaviota Cocinera (Larus dominicanus) sobre los gaviotines Real y Pico Amarillo (Thalasseus maximus y Thalasseus sandvicensis euygnathus, respecti- vamente) en el Área Natural Protegida Punta León, Argentina, durante el 2005 y 2006 para evaluar los cambios potenciales en dicha interacción en relación con lo registrado en la misma localidad a comien- zos de la década de 1990. Al igual que en las evaluaciones previas, la Gaviota Cocinera fue responsable del total de los eventos de depredación sobre ambas especies. Durante el 2006, la tasa de depredación de huevos fue de 0,01 ± 0,003 huevos/hora/nido, igual a la de 1991 y 1992 y levemente menor que la registrada en 1990. Todos las depredaciones de huevos (n = 71) ocurrieron sobre nidos periféricos. A diferencia de estudios previos, se registró la depredación de pichones de ambas especies de gaviotín. Durante el 2005 y 2006 se registraron 43 y 41 intentos de depredación sobre pichones, respectiva- mente, totalizando 18 y 9 eventos exitosos, respectivamente. En el 2005, el 88% de los intentos se rea- lizó sobre pichones en la periferia de los grupos de nidos, mientras que en el 2006 el 63,5% fue sobre pichones en dicha ubicación y el 36,5% restante sobre aquellos en la periferia de las guarderías. Nin- guno de los intentos de depredación de pichones en las guarderías fue exitoso. La relación entre los eventos de depredación y la ubicación de las presas en la colonia muestran la importancia de la estruc- tura espacial en la determinación de las interacciones de depredación en colonias de aves marinas. Los resultados de este estudio muestran que la Gaviota Cocinera sigue siendo el principal depredador de huevos de los gaviotines Real y Pico Amarillo en la colonia de Punta León, observándose tasas de depredación de huevos similares a aquellas registradas en estudios previos. Sin embargo, el impacto de depredación por la Gaviota Cocinera se extendió en años recientes hacia la etapa de pichones de ambas especies de gaviotín.; We studied the predation by Kelp Gull (Larus dominicanus) upon Royal and Cayenne terns (Thalasseus maximus and T. sandvicensis euygnathus, respectively) at the Punta León Protected Area, Argentina, during the 2005 and 2006 breeding seasons to assess changes in the predator-prey interaction with respect to that observed at the same location in the early 1990’s. Similar to previous evaluations, the Kelp Gull was responsible of all predation events on both tern species. During 2006, the predation rate on eggs was 0.01 ± 0.003 eggs/hour/nest, similar to that recorded in 1991 and 1992 and slightly lower that that recorded in 1990. All cases (n = 71) occurred on peripheral nests. In contrast to previous studies, we also recorded predation on chicks of both tern species. During 2005 and 2006 we recorded 43 and 41 predation attempts on chicks, respectively, totaling 18 and 9 successful events, respectively. In 2005, 88% of attempts were on chicks located at the periphery of nest groups, while in 2006 63.5% were on chicks at these locations and the remaining 36.5% on those at the periphery of “crèches”. None of the predation attempts on chicks in “crèches” was successful. The relationship between predation events and the location of prey within the mixed-species colony shows the importance of the spatial structure in the determination of predator-prey interactions in seabird colonies. Our results show that the Kelp Gull is the main predator of Royal and Cayenne terns’ eggs at the Punta León colony, with predation rates similar to those recorded in previous studies. However, the predation impact of Kelp Gulls has extended in recent years to the chick stage of both tern species.
Funciones potenciales y dinamismo de las ciudades medias de la provincia de Buenos Aires, Argentina; Potential functions and dynamics of the medium-sized cities of the province of Buenos Aires, Argentina
Pasciaroni, Carolina
El presente trabajo tiene como objetivo analizar el papel que desempeñan las ciudades medias en el territorio de la Provincia de Buenos Aires (Argentina). Numerosos estudios conciben a las mismas como instrumentos de desconcentración y equilibrio territorial, subrayando su condición de centros proveedores de bienes y servicios a su entorno rural próximo y de recepción de la migración rural - urbana. Los resultados encontrados, en base a la información poblacional de carácter censal y a las estadísticas económicas provinciales, confirman la importancia de las ciudades medias en la región de estudio, tanto en términos de concentración demográfica como de generación de valor agregado. Sin embargo, no resultaron ser las ciudades con mayor crecimiento económico durante los 90s, en comparación con su destacable dinamismo poblacional. Tal comportamiento puede ser interpretado como reflejo de los menores efectos multiplicadores generados por la agricultura local, caracterizada por un alto y sostenido nivel de tecnificación. Palabras claves: ciudades medias, ordenamiento territorial, crecimiento económico, evolución poblacional, interacciones rurales-urbanas.; This article sets out to analyze the role of medium-sized cities in the territory of the Buenos Aires Province (Argentina). Numerous studies interpret medium-sized cities as instruments of territorial balance, underlining their status as suppliers of goods and services to its rural surroundings areas and as a reception centers for the rural - urban migration.The results, based on census population and provincial economic statistics, confirm the importance of mediumsized cities in the region of study, both in terms of population concentration and value added generation. However, medium-sized cities were not the cities with the highest economic growth during the 90s, compared with its remarkable population dynamism. Such behavior can be interpreted as a consequence of the lower multiplier effects generated by local agriculture, characterized by a sustained high level of modernization. Keywords: medium size cities, territorial arrangement, economic growth, population trends, rural-urban interactions.
State-selective charge exchange from Na(3s) and Na*(3p) by highly charged ions
Otranto, Sebastián; Olson, R.E.
State-selective charge exchange cross sections and momentum spectra are calculated for collisions of Xe18+ and Xe54+ ions with Na(3s) and Na*(3p) over the energy range of 0.1–10.0 keV/amu. The classical trajectory Monte Carlo method is used which includes all two-body interactions. The n-level cross sections are found to be rather insensitive to collision energy below 1 keV/amu. In contrast, the transverse momentum cross sections for specific n-levels change rapidly with energy. However, this latter variation in energy is found to be in general agreement with simple scaling rules. Experimental state-selective data are available for Xe18+ over a limited energy range; they are found to be in reasonable accord with the calculations.
The effects of sand temperature on pre-emergent Green Sea Turtle hatchlings; Efecto de la temperatura de la arena en los días previos al emergimiento de neonatos de Tortuga Verde Marina
Segura, Luciano Noel; Cajade, Rodrigo
La temperatura de la arena puede desempeñar un rol importante en la supervivencia de neonatos de tortugas marinas. Altas temperaturas de la arena podrían inhibir la coordinación muscular en el proceso de ascenso hacia la superficie y también disminuir los niveles de oxígeno dentro del nido. Estos factores podrían incrementar la mortalidad de neonatos en los días previos al emergimiento. En este trabajo analizamos los efectos de la temperatura de la arena sobre el periodo de incubación, el éxito de eclosión y porcentaje de emergimiento de nidos de Tortuga Verde Marina (Chelonia mydas) en playas de Tortuguero, Costa Rica. Se seleccionaron nidos desde junio a agosto del año 2000, haciendo coincidir la eclosión con un primer periodo de bajas temperaturas y abundantes precipitaciones (húmedo) y un segundo periodo con mayores temperaturas y escasas precipitaciones (seco). Las temperaturas ambientales y de la arena fueron significativamente mayores en el periodo seco. El aumento en las temperaturas de la arena redujo los días de incubación desde 58,6 ± 0,6 días en el período húmedo a 56,4 ± 0,5 días en el periodo seco. El porcentaje de eclosión y emergimiento tuvieron promedios de 86 ± 3% y 96 ± 1% respectivamente, y no estuvieron asociados con la fecha de inicio del nido. Sin embargo, encontramos una asociación negativa entre el porcentaje de emergimiento y el promedio de temperatura de arena en el cuello del nido en los días previos al emergimiento. Los neonatos podrían morir cuando las temperaturas de la arena superan los 33°C. Considerando el gradual incremento de temperaturas a nivel global, la mortalidad de neonatos en los días previos al emergimiento podría incrementarse y amenazar seriamente a esta población de tortugas verdes marinas; Sand temperature can play an important role in the survival of pre-emergent sea turtle hatchlings. High sand temperatures may inhibit coordinated muscle action in the ascent process to the sand surface and also may cause a decline in oxygen levels within the nest. These factors can increase mortality of hatchlings prior to emergence. In this study we analyze the effects of sand temperature on pre-emergent Green Sea Turtle (Chelonia mydas) hatchlings in Tortuguero, Costa Rica. We also analyze the relationship between sand temperature and egg incubation period, hatching success and hatchling emergence percentage. Nests were selected from June to August 2000, so that hatchlings would emerge during two distinct periods: a period of low temperatures and abundant rainfall mainly during August (wet period, WP) and a period of higher temperatures and lower rainfall mainly during September and early October (dry period, DP). Air and sand temperatures were significantly higher in the DP. Increases in sand temperature reduced incubation period from 58.6 ± 0.6 days in the WP to 56.4 ± 0.5 days in the DP. Mean hatching success and emergence percentage were 86 ± 3% and 96 ± 1%, respectively, and were not associated with the nest initiation date. However, a negative association was found between the emergence percentage and the mean sand temperature at 40 cm depth in the pre-emergence days. Pre-emergent hatchlings may experience increased mortality when sand temperatures at the egg chamber neck level exceed 33°C. When one takes into account global warming projections, hatchling mortality during pre-emergence days could increase and pose a serious threat to this green sea turtle population.
Medanos relícticos intrapampeanos en Daireaux y Centinela del Mar, Buenos Aires; Relict intrapampean dunes in Daireaux and Centinela del Mar, Buenos Aires.
Isla, Federico Ignacio; Dondas, Alejandro; Taglioretti, Matias Luciano
Los sedimentos denominados informalmente "pampeanos" son reconocidos como un paquete de limos y limos arenosos depositados desde el Plioceno superior hasta el Pleistoceno superior, con dos intercalaciones marinas hacias el este, reconocidas fundamentalmente por acumulaciones de valvas marinas: el Interensenadense, y el Belgranense. En el oeste de la provincia de Buenos Aires una extensa área ha sido denominada Mar de arena. En canales próximos a Daireaux y en acantilados marinos de Centinela del Mar, se describieron depósitos arenosos con estratificación diagonal de mesoescala que prueban la presencia de campos de arena por debajo de los depósitos limosos. Las edades del Pleistoceno superior han sido confirmadas por las asociaciones de vertebrados recuperados. En Centinela del Mar, la edad de estos médanos transversales que conformaban una barrera litoral ha sido también confirmada por su vinculación con el máximo nivel del mar alcanzado durante el interglacial Sangamon (Pleistoceno superior, 120.000 años AP).; The sediments informally called "pampeanos" are recognized as a package of silts and sandy silts deposited from the Upper Pliocene to Upper Pleistocene, interfingered with two transgressions to the east, discriminated by shells concentrations: the Interensenadan and the Belgranian transgressions. To the west of the Buenos Aires province, an extended area with dunes was called Sand Sea. Within channels excavated in Daireaux, and sea cliffs from Centinela del Mar, mesoscale crossbeding were described probing the presence of sand fields overlaid by silt deposits. Upper Pleistocene ages were confirmed by the assemblages of vertebrate remains. In Centinela del Mar, the age of these transverse dunes that are composing a littoral barrier was also confirmed in their relation to the maximum sea level highstand reached during the Sangamon interglacial (Upper Pleistocene; 120,000 years BP).
Protein deterioration and longevity of quinoa seeds during long-term storage
Castellion, Martina Laura; Matiacevich, Silvia Beatriz; Buera, Maria del Pilar; Maldonado, Sara Beatriz
Seed protein stability and seed deterioration during storage were studied in seeds of two different quinoa (Chenopodium quinoa Willd.) cultivars, i.e., cv. Ollagüe and cv. Baer II. Germination and viability tests proved that cv. Baer II was more longevous than cv. Ollagüe. Protein insolubilisation was detected during storage and correlated with longevity. However, protein solubility was restored by priming in both cultivars, disregarding their germination capability. Extremely high contents of advanced glycation end-products (AGEs), assessed by carboxymethyllysine (CML) quantification, were obtained from stored seeds as viability was reduced; primed seeds showed slightly lower AGE content, indicating a strong association between quinoa seed ageing and Maillard products accumulation. High intensity fluorescence values were observed in seeds stored in the gene bank bearing 100% germination values, which indicate that the detection of fluorescence is not by itself an appropriate indicator of protein damage by Maillard-type product accumulation in quinoa seeds. This work establishes for the first time a direct association between seed viability and AGE accumulation, due to Maillard reaction, in quinoa seeds.
Variations in flowering phenology and reproductive success in Setaria lachnea
Exner, Eliana de Luján; Zabala, Juan Marcelo; Pensiero, Jose Francisco
Setaria lachnea, moha perenne, is a native grass with excellent forage quality; thus, its introduction to cultivation has been recommended. Therefore, in the present study, the variability in flowering phenology and reproductive success of three Argentine populations from different places by altitudinal gradient have been analyzed, with respect to points of interest for selecting materials. A completely randomized experimental design was used, with 10 genotypes per population and 3 replications per genotype. Flowering phenology was analyzed through variables of flowering start and mid-flowering; the number of panicles was quantified by observation, the number of the total of panicles and reproductive success by fruiting percentage. For flowering start only significant (p£0.05) intrapopulation variations were found. Seventy-five percent of the genotypes started flowering in November 2005. For mid-flowering, there were significant inter- and intra-population differences (p£0.05). The intrapopulation variability observed will allow selecting genotypes with prolonged vegetative period. Reproduction success, measured as mean fruiting percentage, was 41 (high for a nondomesticated species), with variation from 3 % to 80 %. In the two analyzed years (2005-2006), significant inter- and intra-population differences (p£0.05) were found. Genotypes of the population of less height stood out by their high fruiting percentage, always above 40 %; however, there was no variation pattern associated to altitude. Beginning of flowering was not correlated with fruiting percentage; therefore, it will be possible to select late-ripening materials, without altering fruiting percentage. , moha perenne, is a native grass with excellent forage quality; thus, its introduction to cultivation has been recommended. Therefore, in the present study, the variability in flowering phenology and reproductive success of three Argentine populations from different places by altitudinal gradient have been analyzed, with respect to points of interest for selecting materials. A completely randomized experimental design was used, with 10 genotypes per population and 3 replications per genotype. Flowering phenology was analyzed through variables of flowering start and mid-flowering; the number of panicles was quantified by observation, the number of the total of panicles and reproductive success by fruiting percentage. For flowering start only significant (p£0.05) intrapopulation variations were found. Seventy-five percent of the genotypes started flowering in November 2005. For mid-flowering, there were significant inter- and intra-population differences (p£0.05). The intrapopulation variability observed will allow selecting genotypes with prolonged vegetative period. Reproduction success, measured as mean fruiting percentage, was 41 (high for a nondomesticated species), with variation from 3 % to 80 %. In the two analyzed years (2005-2006), significant inter- and intra-population differences (p£0.05) were found. Genotypes of the population of less height stood out by their high fruiting percentage, always above 40 %; however, there was no variation pattern associated to altitude. Beginning of flowering was not correlated with fruiting percentage; therefore, it will be possible to select late-ripening materials, without altering fruiting percentage.
White rot fungi laccases for biotechnological applications
Villalba, Laura L.; Fonseca, Maria Isabel; Giorgio, Ernesto Martín; Zapata, Pedro Dario
White rot fungi have an enzymatic system producing oxidative and hydrolytic enzymes that act on the degradation of certain components of the cell wall. They can be applied in several technological processes, such as paper industry, bio-fuels and environmental pollution. Laccases are multi-copper enzymes of wide substrate specificity and high non-specific oxidation capacity that use molecular oxygen to oxidize various aromatic compounds, and are highly relevant biotechnological applications. In this review, we present some significant patents on laccase production and recombinant DNA technology for diverse biotechnology applications.
Composition of fractional Orlicz maximal operators and A1-weights on spaces of homogeneous type
Bernardis, Ana Lucia; Pradolini, Gladis Guadalupe; Lorente, María; Riveros, Maria Silvina
For a Young function Θ with 0 ≤ α < 1, let Mα,Θ be the fractional Orlicz maximal operator defined in the context of the spaces of homogeneous type (X, d, μ) by Mα,Θf(x) = supx∈Bμ(B)α{double pipe}f{double pipe}Θ,B, where {double pipe}f{double pipe}Θ,B is the mean Luxemburg norm of f on a ball B. When α = 0 we simply denote it by MΘ. In this paper we prove that if Φ and Ψ are two Young functions, there exists a third Young function Θ such that the composition Mα,Ψ {ring operator} MΦ is pointwise equivalent to Mα,Θ. As a consequence we prove that for some Young functions Θ, if Mα,Θf <∞ a.e. and δ ∈ (0,1) then (Mα,Θf)δ is an A1-weight.
Interaction of triflupromazine with distearoylphosphatidylglycerol films studied by surface pressure isotherms and cyclic voltammetry at a 1,2-dichloroethane/water interface
Colqui Quiroga, Mónica Vanesa; Monzon, Lorena Maria Aranzazu; Yudi, Lidia Mabel
The effect of triflupromazine (TFP) on molecular packing of distearoylphosphatidylglycerol (DSPG), adsorbed at the water/1,2-dichloroethane interface, was investigated using cyclic voltammetry (CV) and surface pressure-molecular area isotherm. TFP partition in the DSPG monolayer changes the structure of the film. The results indicate that a fluidizing effect, dependent on the time and the drug concentration, takes place leading to an increase in the permeability of the film. This effect is produced by TFP either from the organic or from the aqueous phase due to the amphiphilic nature of this drug. Nevertheless, the expansion of the film is enhanced when TFP acts from the aqueous phase
Respuestas inmunológicas de las plantas frente al ataque de insectos
Zavala, Jorge Alberto
Las plantas se defienden de sus consumidores a través de sofisticados mecanismos que incluyen pelos urticantes, espinas, compuestos tóxicos para los atacantes o bien compuestos atrayentes para sus depredadores. La comprensión de los procesos moleculares que subyacen en estas respuestas defensivas develan algunos de los misterios acerca de la íntima relación que une a plantas y herbívoros.
Acerca de la elaboración y publicación de la ley en el Derecho indiano
Tau Anzoategui, Víctor
El autor retoma y profundiza anteriores estudios dedicados al problema histórico de la ley en América española entre los siglos XVI y principios del XIX. Luego de establecer el significado de los vocablos que componen el título, el trabajo se ocupa del Consejo, deliberación, elaboración y motivación de las leyes, así como también de las formas de promulgación y publicación. En las consideraciones finales se destacan las peculiaridades de un orden elaborado con sentido creativo por generaciones de juristas para las Indias españolas con posible exposición a otros espacios territoriales y prolongación más allá de la extinción del poder español en América. Este artículo fue elaborado a invitación de la Dirección del Anuario para integrar la posición especial de un volumen monográfico dedicado al tema: "La publicación de las normas en la historia del Derecho español: la era de la imprenta".
Una ilustre familia: la reivindicación del autor en el ensayo de Mario Vargas Llosa
Perilli, Carmen Noemi
Los ensayos literarios de Mario Vargas Llosa disputan el espacio teórico y crítico latinoamericano. Proponen una poética novelesca y un canon literario. Se centran en el Autor y unen dos tradiciones: la narrativa romántica del vate y la narrativa moderna del experto. Vargas Llosa arma el catálogo de una vasta familia de escritores. Las formas vinculares propias de las filiaciones biológicas se apoderan de las afiliaciones culturales. La comunidad está constituida por varones neo-europeos, ilustrados y heterosexuales. Padres, hermanos e hijos marcan la distancia entre un nosotros y ellos/ellas. El nosotros está en el orden de la identidad, alejado de toda alteridad étnica, genérica o cultural. Las figuraciones de autor construyen el linaje del escritor y actúan como dobles especulares que autorizan su escritura.; Mario Vargas Llosa’s literary essays dispute the Latin American theoretical and critical space. They propose a poetic of the novel and a literary canon. Centering on the Author, they link two traditions: the romantic narrative of bards, and the modern narrative of experts. Vargas Llosa assembles a catalog of a vast family of writers. Biological filiation relations take over cultural affiliations. He enlists only heterosexual, illustrated and neo-european males. Fathers, brothers and sons mark the distance between “we” and male/female “they”. “We” is of the order of identity, excluding any ethnic, gender or cultural alterity. Author figurations construct the writer’s lineage, acting as specular doubles authorizing his writing.
On a partly linear autoregressive model with moving average errors
Bianco, Ana Maria; Boente Boente, Graciela Lina
In this paper, we generalise the partly linear autoregression model considered in the literature by including moving average errors when we want to allow a large dependence to the past observations. The strong ergodicity of the process is derived. A consistent procedure to estimate the parametric and nonparametric components is provided together with a test statistic that allows to check the presence of a moving average component in the model. Also, a Monte Carlo study is carried out to check the performance of the given proposals.
Stable p-branes in Chern-Simons AdS supergravities
Edelstein, Jose Daniel; Garbarz, Alan Nicolás; Mišković, Olivera; Zanelli, Jorge
We construct static codimension-two branes in any odd dimension D, with a negative cosmological constant, and show that they are exact solutions of Chern-Simons (super)gravity theory for (super)AdSD coupled to external sources. The stability of these solutions is analyzed by counting the number of preserved supersymmetries. It is shown that static massive (D 3)-branes are unstable unless some suitable gauge fields are added and the brane is extremal. In particular, in three dimensions, a 0-brane is recognized as the negative mass counterpart of the Ban˜ados-Teitelboim-Zanelli black hole. For these 0- branes, we write explicitly magnetically charged Bogomol’nyi-Prasad-Sommerfield states with various numbers of preserved supersymmetries within the OSpðp j 2Þ OSpðq j 2Þ supergroups. In five dimensions, we prove that stable 2-branes with magnetic charge always exist for the generic supergroup SUð2; 4 j NÞ, where N 4. For the special case N ¼ 4, in which Chern-Simons supergravity requires the addition of a nontrivial gauge field configuration in order to preserve the maximal number of degrees of freedom, we show for two different static 2-branes that they are Bogomol’nyi-Prasad-Sommerfield states (one of which is the ground state), and from the corresponding algebra of charges we show that the energy is bounded from below. In higher dimensions, our results admit a straightforward generalization, although there are presumably more solutions corresponding to different intersections of the elementary objects.
Joint diagnostic of the surface air temperature in southern South America and the Madden–Julian oscillation
Naumann, Gustavo; Vargas, Walter Mario
The objective of this research is to explore the relationship between maximum and minimum temperatures, daily precipitation, and the Madden–Julian oscillation (MJO). It was found that the different phases of the MJO show a consistent signal on winter temperature variability and precipitation in southeastern South America. Additionally, this paper explores the spatial–temporal variations of mutual information and joint entropy between temperature and the MJO. A defined spatial pattern was observed with an increased signal in northeastern Argentina and southern Brazil. In the local mutual information analysis, periods in which the mutual information doubled the average values were observed over the entire region. These results indicate that these connections can be used to forecast winter temperatures with a better skill score in situations where both variables covary.
On the formal semantics of IF-like logics
Figueira, Santiago; Gorin, Daniel Alejadro; Grimson, Rafael
In classical logics, the meaning of a formula is invariant with respect to the renaming of bound variables. This property, normally taken for granted, has been shown not to hold in the case of Independence Friendly (IF) logics. In this paper we argue that this is not an inherent characteristic of these logics but a defect in the way in which the compositional semantics given by Hodges for the regular fragment was generalized to arbitrary formulas. We fix this by proposing an alternative formalization, based on a variation of the classical notion of valuation. Basic metatheoretical results are proven. We present these results for Hodges’ slash logic (from which these can be easily transferred to other IF-like logics) and we also consider the flattening operator, for which we give novel game-theoretical semantics.
Optimization problem for extremals of the trace inequality in domains with holes
del Pezzo, Leandro Martin
We study the Sobolev trace constant for functions defined in a bounded domain Ω that vanish in the subset A. We find a formula for the first variation of the Sobolev trace with respect to the hole. As a consequence of this formula, we prove that when Ω is a centered ball, the symmetric hole is critical when we consider deformation that preserve volume but is not optimal for some case.
