1,002 research outputs found
Remote sensing planetary waves in the midlatitude mesosphere using low frequency transmitter signals
Very low and low radio frequency (VLF/LF) propagation responds sensitively to the electron density
distribution in the lower ionosphere (upper mesosphere).
Whereas propagation paths crossing subpolar and polar regions are frequently affected by
forcing from above by particle precipitations, mid- and lowlatitude paths let forcing from below be more
prominent. Our observations (2009â2011) show, that the low frequency propagation conditions along the midlatitude path from Sicily
to Germany (52° N 8° E) using the NSY 45.9 kHz transmitter (37° N 14° E) prove to be a good proxy of mesosphere planetary wave activity
along the propagation path. High absorption events with VLF/LF propagation correlate
to the well known winter time D-layer anomaly observed with high frequency (HF) radio waves.
VLF/LF propagation calculations are presented which show that the radio signal amplitude variations can be modeled by
planetary wave modulated collison frequency and electron density profiles.
The other way around wave pressure amplitudes can be inferred from the VLF/LF data
Personalized lifestyle advice alters affective reactivity to negative events in anhedonic young adults
BACKGROUND: Anhedonia is a common symptom of several disorders, but cost-effective treatments that focus on anhedonia specifically have been lacking. Therefore, personalized lifestyle advice has recently been investigated as a suitable means of enhancing pleasure and positive affect (PA) in young adults with anhedonia. This intervention provided individuals with a personalized lifestyle advice which was based on observed individual patterns of lifestyle behaviors and experienced pleasure in daily life. The present study extends this previous work by examining a potential mechanism of treatment success, affective reactivity. METHODS: We explored changes in affective reactivity to events in daily life from pre- to post-intervention in a subclinical sample of young adults with anhedonia (N = 69). Using the Experience Sampling Method (ESM), participants answered questions on their activities, their pleasure levels, PA and negative affect (NA) before and after the intervention. RESULTS: Multilevel analysis revealed that participants did not experience an altered affective reactivity to positive events after the intervention. The affective reactivity to negative events depended on the level of improvement in mean-PA after the lifestyle advice intervention. LIMITATIONS: The present study used a subclinical sample with the majority of participants being female which limited the generalizability of the findings. CONCLUSION: This study suggests that an altered affective reactivity to negative events is an underlying mechanism of the effectiveness of a personalized lifestyle advice
The uniting of Europe and the foundation of EU studies: revisiting the neofunctionalism of Ernst B. Haas
This article suggests that the neofunctionalist theoretical legacy left by Ernst B. Haas is somewhat richer and more prescient than many contemporary discussants allow. The article develops an argument for routine and detailed re-reading of the corpus of neofunctionalist work (and that of Haas in particular), not only to disabuse contemporary students and scholars of the normally static and stylized reading that discussion of the theory provokes, but also to suggest that the conceptual repertoire of neofunctionalism is able to speak directly to current EU studies and comparative regionalism. Neofunctionalism is situated in its social scientific context before the theory's supposed erroneous reliance on the concept of 'spillover' is discussed critically. A case is then made for viewing Haas's neofunctionalism as a dynamic theory that not only corresponded to established social scientific norms, but did so in ways that were consistent with disciplinary openness and pluralism
Effects of Dicer and Argonaute down-regulation on mRNA levels in human HEK293 cells
RNA interference and the microRNA (miRNA) pathway can induce sequence-specific mRNA degradation and/or translational repression. The human genome encodes hundreds of miRNAs that can post-transcriptionally repress thousands of genes. Using reporter constructs, we observed that degradation of mRNAs bearing sites imperfectly complementary to the endogenous let-7 miRNA is considerably stronger in human HEK293 than HeLa cells. The degradation did not result from the Ago2-mediated endonucleolytic cleavage but it was Dicer- and Ago2-dependent. We used this feature of HEK293 to address the size of a pool of transcripts regulated by RNA silencing in a single cell type. We generated HEK293 cell lines depleted of Dicer or individual Ago proteins. The cell lines were used for microarray analyses to obtain a comprehensive picture of RNA silencing. The 3'-untranslated region sequences of a few hundred transcripts that were commonly up-regulated upon Ago2 and Dicer knock-downs showed a significant enrichment of putative miRNA-binding sites. The up-regulation upon Ago2 and Dicer knock-downs was moderate and we found no evidence, at the mRNA level, for activation of silenced genes. Taken together, our data suggest that, independent of the effect on translation, miRNAs affect levels of a few hundred mRNAs in HEK293 cells
Multiband diffusion-weighted MRI of the eye and orbit free of geometric distortions using a RARE-EPI hybrid
Diffusion-weighted imaging (DWI) provides information on tissue microstructure. Single-shot echo planar imaging (EPI) is the most common technique for DWI applications in the brain, but is prone to geometric distortions and signal voids. Rapid acquisition with relaxation enhancement [RARE, also known as fast spin echo (FSE)] imaging presents a valuable alternative to DWI with high anatomical accuracy. This work proposes a multi-shot diffusion-weighted RARE-EPI hybrid pulse sequence, combining the anatomical integrity of RARE with the imaging speed and radiofrequency (RF) power deposition advantage of EPI. The anatomical integrity of RARE-EPI was demonstrated and quantified by center of gravity analysis for both morphological images and diffusion-weighted acquisitions in phantom and in vivo experiments at 3.0 T and 7.0 T. The results indicate that half of the RARE echoes in the echo train can be replaced by EPI echoes whilst maintaining anatomical accuracy. The reduced RF power deposition of RARE-EPI enabled multiband RF pulses facilitating simultaneous multi-slice imaging. This study shows that diffusion-weighted RARE-EPI has the capability to acquire high fidelity, distortion-free images of the eye and the orbit. It is shown that RARE-EPI maintains the immunity to B0 inhomogeneities reported for RARE imaging. This benefit can be exploited for the assessment of ocular masses and pathological changes of the eye and the orbit
ComposiciĂłn y estructura de la ictiofauna del rĂo Hondo, MĂ©xico-Belice, con base en el uso del arpĂłn
ResumenSe determinĂł la composiciĂłn y estructura de la ictiofauna del rĂo Hondo y la variaciĂłn espacial de Ă©stas en funciĂłn de los parĂĄmetros ambientales. Se realizaron 3 muestreos durante marzo, abril y mayo de 2012, en 6 sitios a lo largo del rĂo. Los datos usados para determinar la estructura se obtuvieron con ayuda de un arpĂłn de 58.5cm, utilizado durante 2h de buceo libre en cada punto de muestreo. Para complementar la lista de especies se utilizaron redes agalleras, palangres, nasas y anzuelos. AdemĂĄs, se realizĂł una revisiĂłn bibliogrĂĄfica y se consultĂł material de la colecciĂłn de peces de ECOSUR en Chetumal. La lista sistemĂĄtica se conformĂł por 40 especies en 33 gĂ©neros, 18 familias y 11 Ăłrdenes. La familia mejor representada fue Cichlidae, incluida la especie exĂłtica Oreochromis niloticus. Los parĂĄmetros ambientales que mejor describieron la variaciĂłn de la distribuciĂłn y abundancia en los peces en el rĂo Hondo fueron: la anchura del rĂo, distancia a la boca, transparencia, profundidad, concentraciĂłn de oxĂgeno disuelto y conductividad. La relaciĂłn entre las especies y las variables ambientales fue alta en ambos ejes (0.89 y 0.79). Ambientalmente, el rĂo se puede zonificar en 3 partes, aunque su ictiofauna puede dividirse en 2 conjuntos principales.AbstractComposition and structure of the Hondo River ichthyofauna and its spatial variation were determined as a function of environmental parameters. Six sites along the river were sampled in March, April and May 2012. Data for estimating structure of fish assemblages was obtained by means of a 58.5cm harpoon during 2 hours of free diving at each sampling site. The species list for the study area was completed with the aid of gillnets, longlines, double-cone traps, and hook-and-line. In addition, a bibliographical research performed as well as the ichthyological collection of ECOSUR at Chetumal was checked. The systematic list includes 40 species in 33 genera, 18 families and 11 orders. The richest family was Cichlidae, including the exotic Oreochromis niloticus. The environmental parameters that best described distribution and abundance of fish in the Hondo River were river width, distance to mouth, transparency, depth, dissolved oxygen concentration, and conductivity. Correlation between species and environmental parameters was high in both axis (0.89 and 0.79). The river was classified into 3 environmental zones, although its fish fauna could be divided in 2 main assemblages
The changing patterns of group politics in Britain
Two interpretations of ways in which group politics in Britain have presented challenges to democracy are reviewed: neo-corporatism or pluralistic stagnation and the rise of single issue interest groups. The disappearance of the first paradigm created a political space for the second to emerge. A three-phase model of group activity is developed: a phase centred around production interests, followed by the development of broadly based 'other regarding' groups, succeeded by fragmented, inner directed groups focusing on particular interests. Explanations of the decay of corporatism are reviewed. Single issue group activity has increased as party membership has declined and is facilitated by changes in traditional media and the development of the internet. Such groups can overload the policy-making process and frustrate depoliticisation. Debates about the constitution and governance have largely ignored these issues and there is need for a debate
Analysis of S. pombe SIN protein association to the SPB reveals two genetically separable states of the SIN.
The Schizosaccharomyces pombe septation initiation network (SIN) regulates cytokinesis, and asymmetric association of SIN proteins with the mitotic spindle pole bodies (SPBs) is important for its regulation. Here, we have used semi-automated image analysis to study SIN proteins in large numbers of wild-type and mutant cells. Our principal conclusions are: first, that the association of Cdc7p with the SPBs in early mitosis is frequently asymmetric, with a bias in favour of the new SPB; second, that the early association of Cdc7p-GFP to the SPB depends on Plo1p but not Spg1p, and is unaffected by mutations that influence its asymmetry in anaphase; third, that Cdc7p asymmetry in anaphase B is delayed by Pom1p and by activation of the spindle assembly checkpoint, and is promoted by Rad24p; and fourth, that the length of the spindle, expressed as a fraction of the length of the cell, at which Cdc7p becomes asymmetric is similar in cells dividing at different sizes. These data reveal that multiple regulatory mechanisms control the SIN in mitosis and lead us to propose a two-state model to describe the SIN
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