Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

El artículo indaga los cambios en la vida política electoral de la provincia de Santiago del Estero a nivel municipal. Estas reflexiones se enmarcan dentro de la sociología política, centrándose en explorar cómo en elecciones nacionales, las disputas políticas electorales en cada municipio pueden dotarse de sentidos y conflictos particulares. Los hallazgos se construyeron en base a dos grandes momentos políticos: el último período del Juarismo (2001-2004) y la del gobierno provincial del Frente Cívico por Santiago (2005-2013). Es un trabajo descriptivo, desde una perspectiva metodológica cualitativa, realizando trabajo de archivo, recolección de información electoral, registro de observación y entrevistas a dirigentes de los partidos y frentes electorales.

This paper analyzes the links between the labor sphere and the love relationships of gay men. Based on interviews with young gay men in Buenos Aires, Argentina, I lay out three labours of love at the crossroads between work and intimacy. First, the identity negotiation when coming out of the closet through a love relationship. Second, the satisfaction of desire and the role of eroticism in access to work or generating seduction in the workplace. Third, the stabilization of the couple and how employment or unemployment becomes an obstacle to overcome. I conclude with the need to analyze the crossings between love and work both from the form and the content.

A feeding trial was carried out to evaluate the utilization of residual nutrients from shrimp farming wastes (SFW) as co-feed in juvenile grey mullets Mugil cephalus. Four treatments were designed to offer shrimp farming wastes in different proportions as feed. The first treatment (control) consisted of feeding the entire daily portion with only commercial feed for marine fish (SFW0). The remaining treatments replaced the daily feed with shrimp farming wastes in 33, 66, and 100%, respectively, treatments SWF33, SWF67, and SWF100. Feed was offered daily as 4% of the grey mullet total biomass at each experimental tank. Results showed that final weight, weight gain, specific growth rate, relative weight gain, and thermal growth coefficient were reduced in the fish when the proportion of SFW in their feed was increased. However, the fish showed a digestive capacity that allowed them to use residual nutrients in a ratio up to 66%, increasing their initial weight by up to 25%. The increase of shrimp farming waste as feed negatively affected the whole-body proximal composition. The digestibility results showed that the fish could digest up to 41% of the shrimp farming waste protein. Results suggest that juvenile grey mullets are capable of utilizing residual nutrients from shrimp farming waste. However, it is necessary to complement an alternative feed source to induce an optimal growth performance for the juvenile grey mullets. It is also recommended that mullets be fed with formulated feed to meet their nutritional requirements to maintain the protein and lipid content of the whole body under culture conditions.

The present study assessed the effect of sea surface temperature (SST) on the individual growth performance of the thread herring Opisthonema libertate in the southern Gulf of California. For the period from 1988 to 2017, based on monthly length-frequency information, the von Bertalanffy equation's growth parameters (L∞, K, and t0) were estimated annually. Annual values of the growth performance index Φ' were inversely related to the SST (P < 0.05). The values of K and L∞ corresponding to the modal value of the distribution of Φ' were taken as representative of the species, and the temperature change pattern function over time was incorporated as a forcing of the growth coefficient, K, in the growth model. Thus, it was possible to represent the yearly effect of SST on growth performance. These estimates are considered of great interest for future research because they directly influence the variability in allocating the number of individuals at different ages.

There has been confusion regarding the specimens identified as "Dendrilla membranosa (Pallas, 1766)" in Antarctic and subantarctic waters, considering that the original description corresponded to specimens from the Indian Ocean. In this study, we clarified the identification of the specimens collected in Argentinian waters, SW Atlantic Ocean, that should be identified as Dendrilla antarctica Topsent, 1905, updating its distributional range and considering the new records reported in the present study.

In recent years resulting investigations in living microbialites have provided significant data that have been critical to disentangle the role of the various biotic and abiotic processes contributing to their development. Despite these efforts separating the impact and magnitude of these processes remain a difficult task. At present the Maquinchao Basin in northeastern Patagonia, Argentina, contains both fossil and living microbialites. Thus, the region provides a unique opportunity to investigate the impact of intrinsic and extrinsic parameters in carbonate precipitation. Early investigations (Austral summer 2011) in living microbialites concluded that organomineralization was related to both photosynthetic activity in the more surficial layer (green), and sulfate-reduction in the lower part (beige). Field investigations in the same area four years later showed that the pounds previously containing abundant active mats had dried out, and in general revealed the absence of globular structured clusters of minerals in the microbial mats. Here we present microscale investigations using optical microscopy and SEM along with the 16SrRNA gene sequence diversity, and the physico-chemical parameters of the hosting waters. They were carried out in successive seasonal samplings in November 2015, April-May 2016, August 2016, February 2017, and March 2018. All microbialite samples show regular occurrences of sulfate reducing bacteria (SRB) along with filaments of unknown origin. Carbonates are observed associated with erect filaments in shallow and active running water locations whereas the mineral phase is located below organic matter film in comparatively deeper and calmer water areas. Additionally, seasonal changes in the physico-chemical properties of the hosting waters indicate that extrinsic parameters, especially evaporation, might play a more substantial role in the precipitation of these carbonates than previously proposed. The environmental differences between 2011 and 2015 in meteorological conditions, regional volcanic activity and associated deposits in the basin are analyzed. We concluded that they are likely responsible of the decrease of the mineralization processes, and particularly those associated with photosynthetic activity.  These results call for caution when interpreting the degree of biological impact on the formation of microbialites in the geological record. Local extrinsic factors might have a changeable impact over time switching mineral precipitation from biotic to abiotic and vice-versa, which can be undistinguishable in fossilized microbialites.

The present study traces a carbonate lamination in microbial mats in a siliciclastic coastal environment. The aim of this paper is to determine how physicochemical and biological processes influence the preservation of sedimentary structures such as ripple marks, covering it by carbonate precipitation. Such precipitation is a combination of the activity of microorganisms, and physicochemical factors. Biological factors, such as photosynthesis, composition and activity of the microbial community, and presence of exopolymeric substances (EPS), play a significant role in coastal environments, while high-energy hydrodynamic events supply seawater, providing calcium and carbonate ions, and trigger events like sediment transport, deposition, and erosion. The combination of these hydrodynamic events with the microbial activity creates physical sedimentary structures, such as ripple marks, which can be biostabilized. The study was conducted in Paso Seco (40°38’40´´S; 62°12´22´´W), a modern coastal flat within an elongated semi-closed basin colonized by microbial mats and categorized as a supratidal zone. Water samples were taken from different ponds within the flat with different degrees of evaporation, and in a tidal creek for hydrochemical analyses. Seawater level fluctuations were measured in the tidal flat over a 10-month period in 2018 using a HOBO water level logger. Ripple field formation over the tidal flat was documented after the occurrence of a strong storm and was monitored throughout three subsequent field trips, and sedimentary samples were taken in a field trip. Petrographic studies show a laterally continuous dense micritic calcite layer, 100–200 µm in thickness, covering the ripple structure, improving the preservation of these bedforms. The presence of microorganisms in the sedimentary environment enables the stabilization of ripple marks because their motility and abundant EPS secretion bind the sediment grains and generate an organic layer that protects them from erosion. On the other hand, the presence of microbial mats contributes to the early preservation of the ripples because they create the adequate conditions for carbonate precipitation. Our observations of modern sedimentary structures and the in situ study of their evolution and early lithification may provide an indicator of microbial colonization and stabilization of ripples in the paleoenvironmental reconstruction.