La conquista del “otro”: en los filmes Aguirre la ira de dios y Fitzcarraldo de W. Herzog (Otros Temas)

La conquista de América fue un hecho violento de expoliación en el que, al tiempo que el conquistador tomó como objeto y pieza de trabajo al indígena, se construyó un imaginario de lo bárbaro. La sed de oro y poder del conquistador creó geografías míticas del paraíso, cuyo ejemplo más significativo es la leyenda de El Dorado, pero también se evidencia en la fiesta barroca que simboliza el desfile de poder por parte de las élites. Este artículo analiza las películas Aguirre y la ira de dios y Fitzcarraldo, de Werner Herzog, quien representó personajes y situaciones, geografías e imágenes de lo exótico.

Factors required for the uridylylation of the foot-and-mouth disease virus 3B1, 3B2, and 3B3 peptides by the RNA-dependent RNA polymerase (3D(pol)) in vitro

The 5' terminus of picornavirus genomic RNA is covalently linked to the virus-encoded peptide 313 (VTg). Foot-and-mouth disease virus (FMDV) is unique in encoding and using 3 distinct forms of this peptide. These peptides each act as primers for RNA synthesis by the virus-encoded RNA polymerase 3D(pol). To act as the primer for positive-strand RNA synthesis, the 3B peptides have to be uridylylated to form VPgpU(pU). For certain picornaviruses, it has been shown that this reaction is achieved by the 3D(pol) in the presence of the 3CD precursor plus an internal RNA sequence termed a cis-acting replication element (cre). The FMDV ere has been identified previously to be within the 5' untranslated region, whereas all other picornavirus cre structures are within the viral coding region. The requirements for the in vitro uridylylation of each of the FMDV 313 peptides has now been determined, and the role of the FMDV ere (also known as the 3B-uridylylation site, or bus) in this reaction has been analyzed. The poly(A) tail does not act as a significant template for FMDV 3B uridylylation.

The poliovirus 2C cis-acting replication element-mediated uridylylation of VPg is not required for synthesis of negative-sense genomes

Nucleotides in the terminal loop of the poliovirus 2C cis-acting replication element (2C(CRE)), a 61 nt structured RNA, function as the template for the addition of two uridylate (U) residues to the viral protein VPg. This uridylylation reaction leads to the formation of VPgpUpU, which is used by the viral RNA polymerase as a nucleotide-peptide primer for genome replication. Although VPg primes both positive- and negative-strand replication, the specific requirement for 2C(CRE)-mediated uridylylation for one or both events has not been demonstrated. We have used a cell-free in vitro translation and replication reaction to demonstrate that 2C(CRE) is not required for the initiation of the negative-sense strand, which is synthesized in the absence of 2C(CRE)-mediated VPgpUpU formation. We propose that the 3' poly(A) tail could serve as the template for the formation of a VPg-poly(U) primer that functions in the initiation of negative-sense strands.

(-)Epicatechin stimulates ERK-dependent cyclic AMP response element activity and up-regulates GluR2 in cortical neurons

Emerging evidence suggests that the cellular actions of flavonoids relate not simply to their antioxidant potential but also to the modulation of protein kinase signalling pathways. We investigated in primary cortical neurons, the ability of the flavan-3-ol, (-)epicatechin, and its human metabolites at physiologically relevant concentrations, to stimulate phosphorylation of the transcription factor cAMP-response element binding protein (CREB), a regulator of neuronal viability and synaptic plasticity. (-)Epicatechin at 100-300 nmol/L stimulated a rapid, extracellular signal-regulated kinase (ERK)- and PI3K-dependent, increase in CREB phosphorylation. At micromolar concentrations, stimulation was no longer apparent and at the highest concentration tested (30 mu mol/L) (-)epicatechin was inhibitory. (-)Epicatechin also stimulated ERK and Akt phosphorylation with similar bell-shaped concentration-response characteristics. The human metabolite 3 '-O-methyl-(-)epicatechin was as effective as (-)epicatechin at stimulating ERK phosphorylation, but (-)epicatechin glucuronide was inactive. (-)Epicatechin and 3 '-O-methyl-(-)epicatechin treatments (100 nmol/L) increased CRE-luciferase activity in cortical neurons in a partially ERK-dependent manner, suggesting the potential to increase CREB-mediated gene expression. mRNA levels of the glutamate receptor subunit GluR2 increased by 60%, measured 18 h after a 15 min exposure to (-)epicatechin and this translated into an increase in GluR2 protein. Thus, (-)epicatechin has the potential to increase CREB-regulated gene expression and increase GluR2 levels and thus modulate neurotransmission, plasticity and synaptogenesis.

Neuroprotective effects of hesperetin in mouse primary neurones are independent of CREB activation

Dietary flavonoids, including the citrus flavanone hesperetin, may have stimulatory, effects on cytoprotective intracellular signalling pathways. In primary mouse cortical neurone cultures, but not SH-SY5Y human neuroblastoma cells or human primary dermal fibroblasts (Promocells), hesperetin (100-300 nM, 15 min) caused significant increases in the level of ERK1/2 phosphorylation, but did not increase CREB phosphorylation. Administration of hesperetin for 18 h did not alter gene expression driven by the cyclic AMP response element (CRE), assessed using a luciferase reporter system, but 300 nM hesperetin partially reversed staurosporine-induced cell death in primary neurones. Our data show that hesperetin is a neuroprotective compound at concentrations where antioxidant effects are unlikely to predominate. The effects of hesperetin are cell-type dependent and, unlike the flavanol (-)epicatechin, neuroprotection in vitro is not associated with enhanced CREB phosphorylation or CRE-mediated gene expression. (C) 2008 Elsevier Ireland Ltd. All rights reserved.

Cloud statistics and cloud radiative effect for a low-mountain site

In 2007, the Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF) was operated for a nine-month period in the Murg Valley, Black Forest, Germany, in support of the Convective and Orographically-induced Precipitation Study (COPS). The synergy of AMF and COPS partner instrumentation was exploited to derive a set of high-quality thermodynamic and cloud property profiles with 30 s resolution. In total, clouds were present 72% of the time, with multi-layer mixed phase (28.4%) and single-layer water clouds (11.3%) occurring most frequently. A comparison with the Cloudnet sites Chilbolton and Lindenberg for the same time period revealed that the Murg Valley exhibits lower liquid water paths (LWPs; median = 37.5 g m−2) compared to the two sites located in flat terrain. In order to evaluate the derived thermodynamic and cloud property profiles, a radiative closure study was performed with independent surface radiation measurements. In clear sky, average differences between calculated and observed surface fluxes are less than 2% and 4% for the short wave and long wave part, respectively. In cloudy situations, differences between simulated and observed fluxes, particularly in the short wave part, are much larger, but most of these can be related to broken cloud situations. The daytime cloud radiative effect (CRE), i.e. the difference of cloudy and clear-sky net fluxes, has been analysed for the whole nine-month period. For overcast, single-layer water clouds, sensitivity studies revealed that the CRE uncertainty is likewise determined by uncertainties in liquid water content and effective radius. For low LWP clouds, CRE uncertainty is dominated by LWP uncertainty; therefore refined retrievals, such as using infrared and/or higher microwave frequencies, are needed.

3D cloud reconstructions: evaluation of scanning radar scan strategy with a view to surface shortwave radiation closure

The ability of six scanning cloud radar scan strategies to reconstruct cumulus cloud fields for radiation study is assessed. Utilizing snapshots of clean and polluted cloud fields from large eddy simulations, an analysis is undertaken of error in both the liquid water path and monochromatic downwelling surface irradiance at 870 nm of the reconstructed cloud fields. Error introduced by radar sensitivity, choice of radar scan strategy, retrieval of liquid water content (LWC), and reconstruction scheme is explored. Given an in␣nitely sensitive radar and perfect LWC retrieval, domain average surface irradiance biases are typically less than 3 W m␣2 ␣m␣1, corresponding to 5–10% of the cloud radiative effect (CRE). However, when using a realistic radar sensitivity of ␣37.5 dBZ at 1 km, optically thin areas and edges of clouds are dif␣cult to detect due to their low radar re-ectivity; in clean conditions, overestimates are of order 10 W m␣2 ␣m␣1 (~20% of the CRE), but in polluted conditions, where the droplets are smaller, this increases to 10–26 W m␣2 ␣m␣1 (~40–100% of the CRE). Drizzle drops are also problematic; if treated as cloud droplets, reconstructions are poor, leading to large underestimates of 20–46 W m␣2 ␣m␣1 in domain average surface irradiance (~40–80% of the CRE). Nevertheless, a synergistic retrieval approach combining the detailed cloud structure obtained from scanning radar with the droplet-size information and location of cloud base gained from other instruments would potentially make accurate solar radiative transfer calculations in broken cloud possible for the first time.

The N-terminal SH2 domain of Syk is required for (hem)ITAM, but not integrin, signaling in mouse platelets

We have used a novel knockin mouse to investigate the effect of disruption of phosphotyrosine binding of the N-terminal SH2 domain of Syk on platelet activation by GPVI, CLEC-2, and integrin αIIbβ3. The Syk(R41Afl/fl) mouse was crossed to a PF4-Cre(+) mouse to induce expression of the Syk mutant in the megakaryocyte/platelet lineage. Syk(R41Afl/fl;PF4-Cre) mice are born at approximately 50% of the expected frequency and have a similar phenotype to Syk(fl/fl;PF4-Cre) mice, including blood-lymphatic mixing and chyloascites. Anastomosis of the venous and lymphatic vasculatures can be seen in the mesenteric circulation accounting for rapid and continuous mixing of the 2 vasculatures. Platelet activation by CLEC-2 and GPVI is abolished in Syk(R41Afl/fl;PF4-Cre) platelets. Syk phosphorylation on Tyr519/20 is blocked in CLEC-2-stimulated platelets, suggesting a model in which binding of Syk via its N-terminal SH2 domain regulates autophosphorylation. In contrast, outside-in signaling by integrin αIIbβ3 is not altered, but it is inhibited in the presence of inhibitors of Src and Syk tyrosine kinases. These results demonstrate that αIIbβ3 regulates Syk through an ITAM-independent pathway in mice and provide novel insight into the course of events underlying Syk activation and hemITAM phosphorylation by CLEC-2.

A novel interaction between FlnA and Syk regulates platelet ITAM-mediated receptor signaling and function

Filamin A (FlnA) cross-links actin filaments and connects the Von Willebrand factor receptor GPIb-IX-V to the underlying cytoskeleton in platelets. Because FlnA deficiency is embryonic lethal, mice lacking FlnA in platelets were generated by breeding FlnA(loxP/loxP) females with GATA1-Cre males. FlnA(loxP/y) GATA1-Cre males have a macrothrombocytopenia and increased tail bleeding times. FlnA-null platelets have decreased expression and altered surface distribution of GPIbalpha because they lack the normal cytoskeletal linkage of GPIbalpha to underlying actin filaments. This results in approximately 70% less platelet coverage on collagen-coated surfaces at shear rates of 1,500/s, compared with wild-type platelets. Unexpectedly, however, immunoreceptor tyrosine-based activation motif (ITAM)- and ITAM-like-mediated signals are severely compromised in FlnA-null platelets. FlnA-null platelets fail to spread and have decreased alpha-granule secretion, integrin alphaIIbbeta3 activation, and protein tyrosine phosphorylation, particularly that of the protein tyrosine kinase Syk and phospholipase C-gamma2, in response to stimulation through the collagen receptor GPVI and the C-type lectin-like receptor 2. This signaling defect was traced to the loss of a novel FlnA-Syk interaction, as Syk binds to FlnA at immunoglobulin-like repeat 5. Our findings reveal that the interaction between FlnA and Syk regulates ITAM- and ITAM-like-containing receptor signaling and platelet function.

Connections between clouds, radiation, and midlatitude dynamics: a review

We review the effects of dynamical variability on clouds and radiation in observations and models and discuss their implications for cloud feedbacks. Jet shifts produce robust meridional dipoles in upper-level clouds and longwave cloud-radiative effect (CRE), but low-level clouds, which do not simply shift with the jet, dominate the shortwave CRE. Because the effect of jet variability on CRE is relatively small, future poleward jet shifts with global warming are only a second-order contribution to the total CRE changes around the midlatitudes, suggesting a dominant role for thermodynamic effects. This implies that constraining the dynamical response is unlikely to reduce the uncertainty in extratropical cloud feedback. However, we argue that uncertainty in the cloud-radiative response does affect the atmospheric circulation response to global warming, by modulating patterns of diabatic forcing. How cloud feedbacks can affect the dynamical response to global warming is an important topic of future research.

Trends in the CERES dataset, 2000–13: the effects of sea ice and jet shifts and comparison to climate models

We review the effects of dynamical variability on clouds and radiation in observations and models and discuss their implications for cloud feedbacks. Jet shifts produce robust meridional dipoles in upper-level clouds and longwave cloud-radiative effect (CRE), but low-level clouds, which do not simply shift with the jet, dominate the shortwave CRE. Because the effect of jet variability on CRE is relatively small, future poleward jet shifts with global warming are only a second-order contribution to the total CRE changes around the midlatitudes, suggesting a dominant role for thermodynamic effects. This implies that constraining the dynamical response is unlikely to reduce the uncertainty in extratropical cloud feedback. However, we argue that uncertainty in the cloud-radiative response does affect the atmospheric circulation response to global warming, by modulating patterns of diabatic forcing. How cloud feedbacks can affect the dynamical response to global warming is an important topic of future research.

Endothelin-1 promotes phosphorylation of CREB transcription factor in primary cultures of neonatal rat cardiac myocytes: implications for the regulation of c-jun expression.

Cardiac myocyte hypertrophy is associated with an increase in expression of immediate early genes (e.g. c-jun) via activation of pre-existing transcription factors. The activity of CREB transcription factor is regulated through phosphorylation of Ser-133 by one of several protein kinases (e.g. protein kinase A (PKA), p90 ribosomal S6 kinases (RSKs) and the related kinase, MSK1). A cell-permeable form of cAMP, hypertrophic agonists (endothelin-1 (ET-1), phenylephrine (PE)) and hyperosmotic shock all promoted phosphorylation of CREB(Ser-133) in rat neonatal cardiac myocytes. The response to endothelin-1 required the extracellular signal-regulated kinase cascade which stimulates both RSKs and MSK1. Phosphorylation of CREB(Ser-133) in response to ET-1 was not associated with any increase in DNA binding to a consensus cAMP-response element (CRE). The rat c-jun promoter contains elements which may bind either c-Jun/ATF2 or CREB/ATF1 dimers. Using extracts from rat cardiac myocytes, we identified at least two complexes which bind to the most proximal of these elements, one of which contained CREB and the other c-Jun. Thus, phosphorylation and activation of CREB in cardiac myocytes may be effected by a range of different stimuli to influence the expression of immediate early genes such as c-jun.

Notch signaling controls the balance of ciliated and secretory cell fates in developing airways

Although there is accumulated evidence of a role for Notch in the developing lung, it is still unclear how disruption of Notch signaling affects lung progenitor cell fate and differentiation events in the airway epithelium. To address this issue, we inactivated Notch signaling conditionally in the endoderm using a Shh-Cre deleter mouse line and mice carrying floxed alleles of the Pofut1 gene, which encodes an O-fucosyltransferase essential for Notch-ligand binding. We also took the same conditional approach to inactivate expression of Rbpjk, which encodes the transcriptional effector of canonical Notch signaling. Strikingly, these mutants showed an almost identical lung phenotype characterized by an absence of secretory Clara cells without evidence of cell death, and showed airways populated essentially by ciliated cells, with an increase in neuroendocrine cells. This phenotype could be further replicated in cultured wild-type lungs by disrupting Notch signaling with a gamma-secretase inhibitor. Our data suggest that Notch acts when commitment to a ciliated or non-ciliated cell fate occurs in proximal progenitors, silencing the ciliated program in the cells that will continue to expand and differentiate into secretory cells. This mechanism may be crucial to define the balance of differentiated cell profiles in different generations of the developing airways. It might also be relevant to mediate the metaplastic changes in the respiratory epithelium that occur in pathological conditions, such as asthma and chronic obstructive pulmonary disease.

Una memoria consensuada : El Informe Rettig

No cabe duda que hoy día la memoria de la dictadura militar (1973-1990) está presente en la vida cotidiana de Chile más que ningún otro periodo histórico. La razón se encuentra en los trágicos sucesos que se vivieron duran- te esos años en materia de derechos humanos. Don Patricio Aylwin, primer presidente electo democráticamente en tras 17 años de autoritarismo y una figura comprometida con los derechos humanos, era consciente de la necesi- dad de investigar la verdad de los crímenes de lesa humanidad ocurridos en Chile. Para ello creó la Comisión Nacional de Verdad y Reconciliación, aunque consideró menester limitar el contenido de su informe con el fin de no amedrentar a las Fuerzas Armadas, las cuales gozaban todavía de mucho poder. Asimismo, el apoyo electoral de los partidos de derecha fue un factor que logró coartar el contenido del informe de la comisión. En este trabajo se presentan aquellas cuestiones que más relevancia tuvieron en la conformación de la verdad de la represión, tales como sus objetivos, sus integrantes y su metodología.

Harold Pinter, cinema e literatura : os limites da realidade

Partindo de duas questões teóricas preliminares, uma, da representação (literária e cinematográfica)do real e do imaginário, tanto no ângulo da produção como no da sua recepção e, a outra, da articulação entre formas de expressão artísticas distintas, ou seja, da interdisciplinaridade, este trabalho examina a presença do tema relativo aos limites entre realidade e fantasia no teatro, no cinema e na literatura, centrando sua atenção na obra de Harold Pinter. Consta de duas partes, cada uma com três capítulos. Na primeira, "Os pressupostos," discute-se as questões que fornecem seu substrato teórico. A segunda é dedicada ao corpus, identificando em seu título o tema investigado: "Os limites da realidade." Quanto à questão da representação, procura-se refutar "a afirmação de que a arte seja uma imitação da realidade. Uma releitura da Poética, de Aristóteles, reforçada pela opinião de diversos estudiosos da mesma, permite afirmar que a mÍmese corresponde, isto sim, a uma representação que envolve uma construção em que elementos da realidade são organizados segundo uma verdade criada pela própria obra, de acordo com critérios inerentes a ela. Além disso, através de uma leitura de Kathryn Hume, procura-se afirmar a interação sinestésica quase que permanente dos impulsos realista e da fantasiana literatura, identificando os tipos com que a fantasia se manifesta e as técnicas usadas para sua criação. A primeira parte encerra-se com um exame do relacionamento da literatura com as artes visuais e dramáticas, relações inter-disciplinares que situam este trabalho na literatura comparada.Dentre vários autores cujas obras contribuem para tal fim, destaca-se Martin Esslin, que estabelece os limitesde cada uma das artes dramáticas, identifica contatos delas com a literatura e permite, através de uma leitura de seu estudo sobre o teatro do absurdo, seja estabelecida a evolução que liga Aristóteles a Pinter. O corpus centra-se na obra de Pinterpara o teatro e para o cinema, sem limitar-se a ela,pois são também analisadas obras de outros escritores e cineastas, estabelendo-se aproximações ou contrastes entre elas. No quarto capítulo estão agrupadas obras nas quais desponta a imposição de verdades pela força fisica ou verbal. A luta pelo poder, a expulsão de elementos estranhos, dúvidas sobre a identidade e a inter-penetrablidade arte-vida caracterizam o capítulo seguinte. A ênfase temática do sexto capítulo recai sobre as limitações impostas pela condição humana. Praticamente todas as obras expressam a impossibilidade da existência de certezas absolutas e de uma perfeita distinção dos limites da realidade. Com isso, é possível afirmar não ser o objetivo da arte reproduzir a realidade. Mesmo que o fosse, tal tentativa resultaria infrutífera devido às limitações humanas.