352 research outputs found

    The Other Migration: Internal Displacement in Chiapas and Health

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    Objectives: To analyze the forced displacement of people in Chiapas for political reasons and to describe the health impacts on the impacted populations

    A Survey of the Reef-Related Medusa (Cnidaria) Community in the Western Caribbean Sea

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    The species composition, distribution, and abundance of medusae collected during a 4-day plankton survey in a reef system of the Mexican Caribbean were studied. Highest mean medusae abundance was observed over the fore-reef zone and in daytime samples. Lowest abundances occurred in the reef lagoon and at dusk. Seventeen species were identified, with Liriope tetraphylla, Aglaura hemistoma, Cubaia aphrodite, and Sarsia prolifera being the most abundant. They belong to a group of medusae dominant along the world\u27s second largest barrier reef. Cluster analysis revealed primary (fore-reef) and secondary (reef lagoon, channel) oceanic groups, showing the strong oceanic influence along and across the reef system. Day-to-day variation in the reef medusan community seemed relatively unimportant. The community structure of the reef medusa fauna appeared to be quite uniform despite the expected migratory behavior of these predators, tidal exchange across the reef, introduction of oceanic species, and time of day. The species composition was most closely related to that of the Campeche Bank and oceanic Caribbean waters. Dominance of oceanic medusae within the reef lagoon was attributed to the narrowness of the continental shelf and the mesoscale hydrological features of the zone

    A Survey of the Reef-Related Medusa (Cnidaria) Community in the Western Caribbean Sea

    Get PDF
    The species composition, distribution, and abundance of medusae collected during a 4-day plankton survey in a reef system of the Mexican Caribbean were studied. Highest mean medusae abundance was observed over the fore-reef zone and in daytime samples. Lowest abundances occurred in the reef lagoon and at dusk. Seventeen species were identified, with Liriope tetraphylla, Aglaura hemistoma, Cubaia aphrodite, and Sarsia prolifera being the most abundant. They belong to a group of medusae dominant along the world\u27s second largest barrier reef. Cluster analysis revealed primary (fore-reef) and secondary (reef lagoon, channel) oceanic groups, showing the strong oceanic influence along and across the reef system. Day-to-day variation in the reef medusan community seemed relatively unimportant. The community structure of the reef medusa fauna appeared to be quite uniform despite the expected migratory behavior of these predators, tidal exchange across the reef, introduction of oceanic species, and time of day. The species composition was most closely related to that of the Campeche Bank and oceanic Caribbean waters. Dominance of oceanic medusae within the reef lagoon was attributed to the narrowness of the continental shelf and the mesoscale hydrological features of the zone

    Utilidad de las secuencias potenciadas en susceptibilidad paramagnética (SWI) para diferenciar crisis somestésicas de accidentes isquémicos transitorios en un paciente con angiopatía amiloide cerebral

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    Background. Cerebral amyloid angiopathy (CAA) is characterized by the deposit of β-amyloid on the walls of small and medium-sized arteries of the cerebral cortex and leptomeninges causing cerebral bleeding. Clinical presentations may include transient neurological events for which differential diagnosis can be difficult. Case report. We report a subject with a medical history of recent stroke who presented somesthetic seizures mimicking transient ischemic attacks owing to CAA microbleeding. Antiplatelet treatment was reduced and after lamotrigine was commenced the episodes disappeared. Susceptibility-weighted magnetic resonance imaging was very helpful for diagnosis (SWI-MRI). Conclusions. CAA microbleeding can be manifested in the form of seizures mimicking focal transient sensitive neurological deficits that can be erroneously attributed to cerebral ischemia. The present case report suggests that, despite the presence of a past medical history of strokes, neurologists should consider CAA microbleeding as a possible cause of pseudo-transient ischemic attacks. High-resolution neuroimaging including SWIMRI imaging can be helpful in identifying cortical microbleedings. In this way, the start or increase of antiplatelet treatment can be avoided, and the risk of potentially fatal complications minimize

    Estimating evaporation from a wet grassland

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    International audienceWet grasslands are being restored across the UK and Europe to reinstate their high biodiversity following over 50 years of drainage and conversion to arable agriculture. The water balance of many wet grasslands is dominated by precipitation and evaporation and it is essential to quantify evaporation rates to understand the hydrological functioning of wetlands and the implications for water resources in catchments where wetlands are being restored. This paper considers data from direct measurements of evaporation from the Pevensey Levels wet grassland using the eddy correlation method. Equations are derived to predict actual evaporation using meteorological data on the site or from standard meteorological station observations. It was found that evaporation could be estimated reliably from meteorological variables, such as wind speed, temperature and humidity and by water availability. It was also found that when water availability is high, evaporation is high and may exceed reference evaporation values, raising questions over the deployment of the two-step Penman-Monteith model unless reliable crop coefficients and relative evaporation figures can be determined

    A satellite DNA array barcodes chromosome 7 and regulates totipotency via ZFP819.

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    Mammalian genomes are a battleground for genetic conflict between repetitive elements and KRAB-zinc finger proteins (KZFPs). We asked whether KZFPs can regulate cell fate by using ZFP819, which targets a satellite DNA array, ZP3AR. ZP3AR coats megabase regions of chromosome 7 encompassing genes encoding ZSCAN4, a master transcription factor of totipotency. Depleting ZFP819 in mouse embryonic stem cells (mESCs) causes them to transition to a 2-cell (2C)-like state, whereby the ZP3AR array switches from a poised to an active enhancer state. This is accompanied by a global erosion of heterochromatin roadblocks, which we link to decreased SETDB1 stability. These events result in transcription of active LINE-1 elements and impaired differentiation. In summary, ZFP819 and TRIM28 partner up to close chromatin across Zscan4, to promote exit from totipotency. We propose that satellite DNAs may control developmental fate transitions by barcoding and switching off master transcription factor genes

    Polynomial Heuristic Algorithms for Inconsistency Characterization in Firewall Rule Sets

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    Firewalls provide the first line of defence of nearly all networked institutions today. However, Firewall ACLs could have inconsistencies, allowing traffic that should be denied or vice versa. In this paper, we analyze the inconsistency characterization problem as a separate problem of the diagnosis one, and propose formal definitions in order to characterize one-to-many inconsistencies. We identify the combinatorial part of the problem that generates exponential complexities in combined diagnosis and characterization algorithms proposed by other authors. Then we propose a decomposition of the combinatorial problem in several smaller combinatorial ones, which can effectively reduce the complexity of the problem. Finally, we propose an approximate heuristic and algorithms to solve the problem in worst case polynomial time. Although many algorithms have been proposed to address this problem, all of them are combinatorial. The presented algorithms are an heuristic way to solve the problem with polynomial complexity. There are no constraints on how rule field ranges are expressed

    Co-option of endogenous retroviruses through genetic escape from TRIM28 repression

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    Endogenous retroviruses (ERVs) have rewired host gene networks. To explore the origins of co-option, we employed an active murine ERV, IAPEz, and an embryonic stem cell (ESC) to neural progenitor cell (NPC) differentiation model. Transcriptional silencing via TRIM28 maps to a 190 bp sequence encoding the intracisternal A-type particle (IAP) signal peptide, which confers retrotransposition activity. A subset of "escapee" IAPs (∼15%) exhibits significant genetic divergence from this sequence. Canonical repressed IAPs succumb to a previously undocumented demarcation by H3K9me3 and H3K27me3 in NPCs. Escapee IAPs, in contrast, evade repression in both cell types, resulting in their transcriptional derepression, particularly in NPCs. We validate the enhancer function of a 47 bp sequence within the U3 region of the long terminal repeat (LTR) and show that escapee IAPs convey an activating effect on nearby neural genes. In sum, co-opted ERVs stem from genetic escapees that have lost vital sequences required for both TRIM28 restriction and autonomous retrotransposition

    Estudio de similitudes entre áreas temáticas

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    In this paper some results are presented which permit the graphic representation of the similarities between subjects which appear on web pages found on the Internet. To this end, these similarities are quantified and graphically represented by means of an index between the different subjects, in accordance with an intuitive interpretation of similarity between sets. The use of a function based on Learning Theory, enable us to study the similarity or interrelation between different lines of investigations corresponding to information on web pages. The visual analysis of the aforementioned interrelations has been applied to the area of Learning research refering to the period May 2003-May 2004. Furthermore, various tables which clarify the potential of this similarity index are constructed.En este trabajo presentamos unos resultados que permiten la representación gráfica de las similitudes entre centros de interés que aparecen en las páginas Web que se encuentran distribuidas en Internet. Para ello se cuantifica y representa gráficamente por medio de un índice de similitud entre los diferentes centros de interés, de acuerdo a una interpretación intuitiva de similitud entre conjuntos. La utilización de una función procedente de la teoría del aprendizaje nos permite estudiar, a partir de la información en las páginas Web, la similitud o interrelación que existe entre diferentes líneas de investigación. El análisis visual de dichas interrelaciones se ha aplicado al área de investigación del aprendizaje referido al período mayo 2003-mayo 2004. Asimismo, se construyen varias tablas que aclaran la potencialidad futura de este índice de similitud

    Time-calibrated molecular phylogeny of pteropods

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    © 2017 Burridge et al. This is an open access article distributed under the terms of the [4.0] Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. The attached file is the published version of the article
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