Response of P, K, Mg and NO‚́ƒ-N contents of carrots to irrigation, soil compaction, and nitrogen fertilisation

Selostus: Maan tiiviyden, sadetuksen ja typpilannoituksen vaikutus porkkanan kivennäisainepitoisuuteen ja ravinteiden ottoon sekä nitraatin kertymiseen

Predacion de semillas de Amaranthus quitensis H.B.K. en un cultivo de soja: influencia del sistema de siembra

El objetivo fue evaluar las pérdidas del banco superficial de semillas de Amaranthus quitensis H.B.K. (yuyo colorado) debidas a la predación por insectos en un cultivo de soja y en el barbecho posterior, en dos sistemas de laboreo. Los experimentos se realizaron durante las campañas 94/95 y 95/96. Para calcular la tasa de predación se emplearon bandejas cubiertas con tejido para evitar el ingreso de roedores y con tela de tul en los tratamientos testigos; en cada una se sembraron 100 semillas de la maleza y cada 15 días se registró el número de semillas remanentes. Para determinar los insectos presentes y su abundancia se emplearon trampas "pitfall". Entre los insectos capturados se encontró el carábido Notiobia cupripennis, su mayor abundancia se registró en marzo (4,5 y 5,8 insectos/trampa en convencional y 2,7 y 3,3 insectos/trampa en siembra directa), coincidiendo con las tasas de predación más altas (5,6% y 8% en convencional y 2,7% y 3,8% en siembra directa); tanto en abundancia como en predación se observaron diferencias significativas entre ambos sistemas. A partir de este mes, las diferencias no fueron significativas, el número de insectos y la tasa de predación disminuyeron. En ambos años existió una correlación positiva entre estas variables.

People on the Edge See More. A conversation with the cuban-american writer Cristina García

L'entrevista amb l'escriptora cubano-americana Cristina García explora el tema de la identitat cubanoamericana i desvetlla la riquesa literària que sorgeix de la fusió de dues cultures, la cubana i la nord-americana, i com aquesta fusió innova la literatura nord-americana tradicional. En la seva novel·la, Dreaming in Cuban (1992), l'escriptora explora els efectes de la Revolució castrista des de la perspectiva de les dones cubanes que van quedar-se a l'illa, així com de les dones que emigraren als Estats Units. The conversation with Cuban-American writer Cristina García explores what it means to be Cuban-American, and reveals how to grow bicultural enriches mainstream American literature. In her novel Dreaming in Cuban (1992), the writer explores the effects of the Castro Revolution from the perspective of Cuban women who remained in Cuba, as well as from the experience of women who emigrated to the United States.

Differential regulation of Na-K-ATPase isoform gene expression by T3 during rat brain development.

A fetal rat telencephalon organotypic cell culture system was found to reproduce the developmental pattern of Na-K-adenosinetriphosphatase (ATPase) gene expression observed in vivo [Am. J. Physiol. 258 (Cell Physiol. 27): C1062-C1069, 1990]. We have used this culture system to study the effects of triiodothyronine (T3; 0.003-30 nM) on mRNA abundance and basal transcription rates of Na-K-ATPase isoforms. Steady-state mRNA levels were low at culture day 6 (corresponding to the day of birth) but distinct for each isoform alpha 3 much greater than beta 1 = beta 2 greater than alpha 2 greater than alpha 1. At culture day 6, T3 did not modify mRNA abundance of any isoform. At culture day 12 (corresponding to day 7 postnatal), T3 increased the mRNA level of alpha 2 (4- to 7-fold), beta 2 (4- to 5-fold), alpha 1 (3- to 6-fold), and beta 1 (1.5-fold), whereas alpha 3 mRNA levels remained unchanged. Interestingly, the basal transcription rate for each isoform differed strikingly (alpha 2 greater than alpha 1 much greater than beta 1 = beta 2 greater than alpha 3) but remained stable throughout 12 days of culture and was not regulated by T3. Thus we observed an inverse relationship between rate of transcription and rate of mRNA accumulation for each alpha-isoform, suggesting that alpha 1- and alpha 2-mRNA are turning over rapidly whereas alpha 3-mRNA is turning over slowly. Our data indicate that one of the mechanisms by which T3 selectively controls Na-K-ATPase gene expression during brain development in vitro occurs at the posttranscriptional level.

MRI of coronary vessel walls using radial k-space sampling and steady-state free precession imaging.

OBJECTIVE: The objective of our study was to investigate the impact of radial k-space sampling and steady-state free precession (SSFP) imaging on image quality in MRI of coronary vessel walls. SUBJECTS AND METHODS: Eleven subjects were examined on a 1.5-T MR system using three high-resolution navigator-gated and cardiac-triggered 3D black blood sequences (cartesian gradient-echo [GRE], radial GRE, and radial SSFP) with identical spatial resolution (0.9 x 0.9 x 2.4 mm3). The signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), vessel wall sharpness, and motion artifacts were analyzed. RESULTS: The mean SNR and CNR of the coronary vessel wall were improved using radial imaging and were best using radial k-space sampling combined with SSFP imaging. Vessel border definition was similar for all three sequences. Radial k-space sampling was found to be less sensitive to motion. Consistently good image quality was seen with the radial GRE sequence. CONCLUSION: Radial k-space sampling in MRI of coronary vessel walls resulted in fewer motion artifacts and improved SNR and CNR. The use of SSFP imaging, however, did not result in improved coronary vessel wall visualization.

ConnectomeViewer - Multi-Modal Multi-Level Network Visualization and Analysis.

Introduction: The field of Connectomic research is growing rapidly, resulting from methodological advances in structural neuroimaging on many spatial scales. Especially progress in Diffusion MRI data acquisition and processing made available macroscopic structural connectivity maps in vivo through Connectome Mapping Pipelines (Hagmann et al, 2008) into so-called Connectomes (Hagmann 2005, Sporns et al, 2005). They exhibit both spatial and topological information that constrain functional imaging studies and are relevant in their interpretation. The need for a special-purpose software tool for both clinical researchers and neuroscientists to support investigations of such connectome data has grown. Methods: We developed the ConnectomeViewer, a powerful, extensible software tool for visualization and analysis in connectomic research. It uses the novel defined container-like Connectome File Format, specifying networks (GraphML), surfaces (Gifti), volumes (Nifti), track data (TrackVis) and metadata. Usage of Python as programming language allows it to by cross-platform and have access to a multitude of scientific libraries. Results: Using a flexible plugin architecture, it is possible to enhance functionality for specific purposes easily. Following features are already implemented: * Ready usage of libraries, e.g. for complex network analysis (NetworkX) and data plotting (Matplotlib). More brain connectivity measures will be implemented in a future release (Rubinov et al, 2009). * 3D View of networks with node positioning based on corresponding ROI surface patch. Other layouts possible. * Picking functionality to select nodes, select edges, get more node information (ConnectomeWiki), toggle surface representations * Interactive thresholding and modality selection of edge properties using filters * Arbitrary metadata can be stored for networks, thereby allowing e.g. group-based analysis or meta-analysis. * Python Shell for scripting. Application data is exposed and can be modified or used for further post-processing. * Visualization pipelines using filters and modules can be composed with Mayavi (Ramachandran et al, 2008). * Interface to TrackVis to visualize track data. Selected nodes are converted to ROIs for fiber filtering The Connectome Mapping Pipeline (Hagmann et al, 2008) processed 20 healthy subjects into an average Connectome dataset. The Figures show the ConnectomeViewer user interface using this dataset. Connections are shown that occur in all 20 subjects. The dataset is freely available from the homepage (connectomeviewer.org). Conclusions: The ConnectomeViewer is a cross-platform, open-source software tool that provides extensive visualization and analysis capabilities for connectomic research. It has a modular architecture, integrates relevant datatypes and is completely scriptable. Visit www.connectomics.org to get involved as user or developer.

Probabilidade de resposta da cana-de-açúcar à adubação potássica em razão da relação K+ (Ca2++Mg2+ )-0,5 do solo

O objetivo deste trabalho foi avaliar a probabilidade de resposta da produção de cana-de-açúcar à adubação potássica, em razão da relação K+ (Ca2++Mg2+ )-0,5 no solo. Foram compilados dados de 106 experimentos de adubação potássica na cana-de-açúcar. Em cada experimento foi registrado o ciclo de cultivo (cana-planta ou cana-soca), os teores de K, Ca e Mg do solo antes da adubação potássica, a relação K+ (Ca2++Mg2+ )-0,5, e se houve, ou não, resposta estatisticamente significativa da produção à adubação potássica. Foi utilizado o método estatístico de regressão logística, efetuado pelo procedimento CATMOD do Statistical Analysis System. A característica ciclo de cultivo foi eliminada do modelo, pois esta se apresentou como não-significativa no ajuste estatístico. A relação K+ (Ca2++Mg2+ )-0,5 do solo influenciou a probabilidade de resposta da produção de cana-de-açúcar à adubação potássica. À medida que a relação K+ (Ca2++Mg2+ )-0,5 aumentou, a probabilidade de resposta da produção de cana-de-açúcar à adubação potássica diminuiu. A relação K+ (Ca2++Mg2+ )-0,5 no solo foi classificada em baixa (<0,2547), média (0,2547 a 0,3349) e alta (>0,3349). A relação K+ (Ca2++Mg2+ )-0,5 no solo deve ser usada como mais um critério para orientar a adubação potássica na cultura da cana-de-açúcar.

People on the Edge See More. A conversation with the cuban-american writer Cristina García

L'entrevista amb l'escriptora cubano-americana Cristina García explora el tema de la identitat cubanoamericana i desvetlla la riquesa literària que sorgeix de la fusió de dues cultures, la cubana i la nord-americana, i com aquesta fusió innova la literatura nord-americana tradicional. En la seva novel·la, Dreaming in Cuban (1992), l'escriptora explora els efectes de la Revolució castrista des de la perspectiva de les dones cubanes que van quedar-se a l'illa, així com de les dones que emigraren als Estats Units. The conversation with Cuban-American writer Cristina García explores what it means to be Cuban-American, and reveals how to grow bicultural enriches mainstream American literature. In her novel Dreaming in Cuban (1992), the writer explores the effects of the Castro Revolution from the perspective of Cuban women who remained in Cuba, as well as from the experience of women who emigrated to the United States.

Cutting edge: cell autonomous rather than environmental factors control bacterial superantigen-induced T cell anergy in vivo.

Anergic T cells display a marked decrease in their ability to produce IL-2 and to proliferate in the presence of an appropriate antigenic signal. Two nonmutually exclusive classes of models have been proposed to explain the persistence of T cell anergy in vivo. While some reports indicate that anergic T cells have intrinsic defects in signaling pathways or transcriptional activities, other studies suggest that anergy is maintained by environmental "suppressor" factors such as cytokines or Abs. To distinguish between these conflicting hypotheses, we employed the well-characterized bacterial superantigen model system to evaluate in vivo the ability of a trace population of adoptively transferred naive or anergized T cells to proliferate in a naive vs anergic environment upon subsequent challenge. Our data clearly demonstrate that bacterial superantigen-induced T cell anergy is cell autonomous and independent of environmental factors.