The effects of UV radiation on photosynthesis estimated as chlorophyll fluorescence in Zygnemopsis decussata (Chlorophyta) growing in a high mountain lake (Sierra Nevada, Southern Spain)

The effect of increased UV radiation on photosynthesis estimated as in vivo chlorophyll fluorescence i.e. optimal quantum yield (F(v)/F(m)) and electron transport rate (ETR) in the green filamentous alga Zygnemopsis decussata (Streptophyta, Zygnematales) growing in the high mountain lake ""La Caldera"" (Sierra Nevada, Spain) at 3050 m altitude was evaluated. Two sets of in situ experiments were conducted: (1) On July 2006, F(v)/F(m) was measured throughout the day at different depths (0.1, 0.25, 0.5 and 1 m) and in the afternoon. ETR and phenolic compounds were determined. In addition, in order to analyze the effect of UV radiation, F(v)/F(m) was determined in algae incubated for 3 days at 0.5m under three different light treatments: PAR+UVA+UVB (PAB). PAR+UVA (PA) and PAR (P). (2) On August 2007, F(v)/F(m) was determined under PAB, PA and P treatments and desiccation/rehydration conditions. F(v)/F(m) decreased in algae growing in surface waters (0.1 m) but also at 1 m depth compared to that at 0.5 in depth. The decrease of F(v)/F(m) at noon due to photoinhibition was small (less than 10%) except in algae growing at 1 m depth (44%). The maximal electron transport rate was 3.5-5 times higher in algae growing at 0.25-0.5 m respectively than that at 0.1 and 1 m depth. These results are related to the accumulation of phenolic compounds: i.e. the algae at 0.25-0.5 in presentedrespectively about a 3-5 times higher concentration of phenolic compounds than that of algae at 0.1-1 m depth. The protection mechanisms seem to be stimulated by UVB radiation, since F(v)/F(m) was higher in the presence of UVB (PAB treatment) compared to PA or P treatments. UVA exerts the main photoinhibitory effect, not Only at midday, but also in the afternoon. UVB radiation also had a protective effect in algae grown under desiccation conditions for three days. During re-hydration, the rapid increase of F(v)/F(m) (after 1 h) was higher in the UVB-grown algae than in algae grown under UVA radiation. After 5 h. F(v)/F(m) values were similar in algae submitted to desiccation/rehydration under PAB and P treatments as they were in the control (submerged algae). The combined effect of desiccation and UVA produced the greatest decrease of photosynthesis in Z. decussata. Thifs UVB, in contrast to other species, may support the recovery process. Z. decussata can acclimate to severe stress, conditions in this high mountain lake by the photoprotection mechanism induced by UVB radiation through dynamic photoinhibition and the accumulation of phenolic compounds (UV screen and antioxidant substances).

Paleomagnetic data and K-Ar ages from Mesozoic units of the Santa Marta massif: A preliminary interpretation for block rotation and translations

We report 6 K-Ar ages and paleomagnetic data from 28 sites collected in Jurassic, Lower Cretaceous and Paleocene rocks of the Santa Marta massif, to test previous hypothesis of rotations and translations of this massif, whose rock assemblage differs from other basement-cored ranges adjacent to the Guyana margin. Three magnetic components were identified in this study. A first component has a direction parallel to the present magnetic field and was uncovered in all units (D 352, I = 25.6, k = 57.35, a95 = 5.3, N = 12). A second component was isolated in Cretaceous limestone and Jurassic volcaniclastic rocks (D = 8.8, I = 8.3, k = 24.71, a95 = 13.7, N = 6), and it was interpreted as of Early Cretaceous age. In Jurassic sites with this component, Early Cretaceous K-Ar ages obtained from this and previous studies are interpreted as reset ages. The third component was uncovered in eight sites of Jurassic volcaniclastic rocks, and its direction indicates negative shallow to moderate inclinations and northeastward declinations. K-Ar ages in these sites are of Early (196.5 +/- 4.9 Ma) to early Late Jurassic age (156.6 +/- 8.9 Ma). Due to local structural complexity and too few Cretaceous outcrops to perform a reliable unconformity test, we only used two sites with (1) K-Ar ages, (2) less structural complexity, and (3) reliable structural data for Jurassic and Cretaceous rocks. The mean direction of the Jurassic component is (D = 20.4, I = -18.2, k = 46.9, a95 = 5.1, n = 18 specimens from two sites). These paleomagnetic data support previous models of northward along-margin translations of Grenvillian-cored massifs. Additionally, clockwise vertical-axis rotation of this massif, with respect to the stable craton, is also documented; the sense of rotation is similar to that proposed for the Perija Range and other ranges of the southern Caribbean margin. More data is needed to confirm the magnitudes of rotations and translations. (C) 2009 Elsevier Ltd. All rights reserved.

O mercado sobe a favela: um estudo sobre o Santa Marta pós-UPP

O presente estudo de caso teve por objetivo identificar como a implantação da Unidade de Polícia Pacificadora na favela Santa Marta, na Zona Sul do Rio de Janeiro, alterou a interação do mercado com esta comunidade e como isso afetou as relações sociais na favela a partir da percepção dos moradores. O intuito era perceber como o mercado interno, seja ele formal ou informal, tem respondido à nova conjuntura e como atores do mercado externo, como Firjan, Light, entre outros, vêm atuando no local. Ademais, buscou-se analisar como essa nova dinâmica do mercado, viabilizada pela maior presença do estado no Santa Marta, influenciou a sociabilidade local. Para tal, por meio de pesquisa de campo, foram realizadas observações participantes e entrevistas semi-abertas com representantes de empresas que atuam na comunidade, empreendedores locais, moradores e lideranças. Concluiu-se que a expansão do mercado interno e da atuação do mercado externo na comunidade, permite que alguns benefícios cheguem; contudo, essa nova conjuntura tem gerado inseguranças nos moradores que sentem que tiveram espaços de lazer restringidos com o aumento do turismo e eventos festivos para o público externo, receiam não ter condições de arcar com o aumento do custo de vida e conseqüente empobrecimento e temem que venham a sofrer um processo de remoção branca causada pela pressão do mercado. Assim, alguns terão condições de aproveitar e até se desenvolver com as oportunidades que têm surgido com a expansão do mercado, enquanto outros, provavelmente, não terão capacidade e sofrerão uma nova exclusão.

Gringos no Santa Marta: quem são, o que pensam e como avaliam a experiência turística na favela

Neste artigo analisamos a experiência turística de visitantes estrangeiros na favela Santa Marta, localizada na Zona Sul do Rio de Janeiro. Buscamos identificar o perfil do turista, os agentes envolvidos na realização dos tours, as impressões a respeito da visitação e o modo como os turistas avaliaram não apenas os equipamentos turísticos presentes na localidade, mas também a própria experiência no reality tour.

La significación que le otorgan a la institucionalización de adultos mayores las familias y cuidadores formales del Hogar Santa Marta

Nuestros padres envejecen y viven mucho más tiempo. Quedó lejos la época en que los ancianos eran grupos de sabios, ricos en experiencia, guardianes de las tradiciones y portadores del saber. En el siglo XVII se era viejo a los cuarenta, al comienzo del siglo XXI muchas personas se sienten jóvenes a los sesenta o setenta años. Las sociedades modernas muestran altos índices de población adulta mayor, denominado este fenómeno envejecimiento poblacional. Como vemos, los progresos de la medicina y el bienestar han logrado mejoras sensibles en la salud y las condiciones de vida de las personas de edad avanzada. El promedio de vida se ha elevado con la ayuda de la ciencia, la tecnología y la mejora en la calidad de vida. La naturaleza real del proceso de envejecimiento hace difícil medir y definir cuando una persona es vieja. Actualmente, además de la edad, cuentan otras características personales como el estado físico, enfermedades, historia personal, familiar y profesional. Es decir que se envejece de una manera diferenciada. Como manifiesta Mónica Roqué “El envejecimiento es un proceso largo que comienza cuando nacemos y finaliza con la muerte. Desde el punto de vista individual, es inexorable, todos envejecemos. La edad física (cronológica) es una variable importante, pero no la única, puesto que no todas las personas envejecen o cambian físicamente al mismo tiempo sino que la historia de vida, su salud, educación, trabajo, nutrición, relaciones familiares, etc., diferencian a las personas en la vejez". Hablar brevemente de envejecimiento me lleva a señalar que el tema en cuestión fue escogido porque en nuestro país la institucionalización de Adultos Mayores se haconvertido en una realidad socialmente relevante, ya que “Las cifras del envejecimiento revelan en la Argentina, en consonancia con las tendencias a nivel mundial, el incremento de la población en la franja de los mayores de sesenta años y el aumento de la longevidad. En este contexto poblacional, especialmente por el aumento de los diversos tipos de dependencia, se ha originado en la segunda mitad del siglo XX el incremento de la institucionalización".

Las memorias que seremos : Memoria y olvido en el discurso oficial sobre el conflicto armado colombiano en el pasado reciente

Fil: Zuluaga Aristizábal, Marda Ucaris. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.

Las memorias que seremos : Memoria y olvido en el discurso oficial sobre el conflicto armado colombiano en el pasado reciente

Fil: Zuluaga Aristizábal, Marda Ucaris. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina.