2,495 research outputs found

    High Redshift HCN Emission: Dense Star-Forming Molecular Gas in IRAS F10214+4724

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    Hydrogen cyanide emission in the J=1-0 transition has been detected at redshift z=2.2858 in IRAS F10214+4724 using the Green Bank Telescope . This is the second detection of HCN emission at high redshift. The large HCN line luminosity in F10214 is similar to that in the Cloverleaf (z=2.6) and the ultra-luminous infrared galaxies Mrk231 and Arp220. This is also true of the ratio of HCN to CO luminosities. The ratio of far-infrared luminosity to HCN luminosity, an indicator of the star formation rate per solar mass of dense gas, follows the correlation found for normal spirals and infrared luminous starburst galaxies. F10214 clearly contains a starburst that contributes, together with its embedded quasar, to its overall infrared luminosity. A new technique for removing spectral baselines in the search for weak, broad emission lines is presented.Comment: 9 pages, 2 figures; accepted ApJ(Letters

    Where do bright ideas occur in our brain? Meta-analytic evidence from neuroimaging studies of domain-specific creativity

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    Many studies have assessed the neural underpinnings of creativity, failing to find a clear anatomical localization. We aimed to provide evidence for a multi-componential neural system for creativity. We applied a general activation likelihood estimation (ALE) meta-analysis to 45 fMRI studies. Three individual ALE analyses were performed to assess creativity in different cognitive domains (Musical, Verbal, and Visuo-spatial). The general ALE revealed that creativity relies on clusters of activations in the bilateral occipital, parietal, frontal, and temporal lobes. The individual ALE revealed different maximal activation in different domains. Musical creativity yields activations in the bilateral medial frontal gyrus, in the left cingulate gyrus, middle frontal gyrus, and inferior parietal lobule and in the right postcentral and fusiform gyri. Verbal creativity yields activations mainly located in the left hemisphere, in the prefrontal cortex, middle and superior temporal gyri, inferior parietal lobule, postcentral and supramarginal gyri, middle occipital gyrus, and insula. The right inferior frontal gyrus and the lingual gyrus were also activated. Visuo-spatial creativity activates the right middle and inferior frontal gyri, the bilateral thalamus and the left precentral gyrus. This evidence suggests that creativity relies on multi-componential neural networks and that different creativity domains depend on different brain regions

    Differences in spatial memory recognition due to cognitive style

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    Field independence refers to the ability to perceive details from the surrounding context as a whole and to represent the environment by relying on an internal reference frame. Conversely, field dependence individuals tend to focus their attention on single environmental features analysing them individually. This cognitive style affects several visuo-spatial abilities including spatial memory. This study assesses both the effect of field independence and field dependence on performance displayed on virtual environments of different complexity. Forty young healthy individuals took part in this study. Participants performed the Embedded Figures Test for field independence or dependence assessment and a new spatial memory recognition test. The spatial memory recognition test demanded to memorize a green box location in a virtual room picture. Thereafter, during ten trials participants had to decide if a green box was located in the same position as in the sample picture. Five of the pictures were correct. The information available in the virtual room was manipulated. Hence, two different experimental conditions were tested: a virtual room containing all landmarks and a virtual room with only two cues. Accuracy and reaction time were registered. Analyses demonstrated that higher field independent individuals were related to better spatial memory performance in two landmarks condition and were faster in all landmark condition. In addition, men and women did not differ in their performance. These results suggested that cognitive style affects spatial memory performance and this phenomenon is modulated by environment complexity. This does not affect accuracy but time spent. Moreover, field dependent individuals are unable to organize the navigational field by relying on internal reference frames when few landmarks are available, and this causes them to commit more errors

    The binary companion mass ratio distribution: an imprint of the star formation process?

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    We explore the effects of dynamical evolution in dense clusters on the companion mass ratio distribution (CMRD) of binary stars. Binary systems are destroyed by interactions with other stars in the cluster, lowering the total binary fraction and significantly altering the initial semi-major axis distribution. However, the shape of the CMRD is unaffected by dynamics; an equal number of systems with high mass ratios are destroyed compared to systems with low mass ratios. We might expect a weak dependence of the survivability of a binary on its mass ratio because its binding energy is proportional to both the primary and secondary mass components of the system. However, binaries are broken up by interactions in which the perturbing star has a significantly higher energy (by a factor of >10, depending on the particular binary properties) than the binding energy of the binary, or through multiple interactions in the cluster. We therefore suggest that the shape of the observed binary CMRD is an outcome of the star formation process, and should be measured in preference to the distributions of orbital parameters, such as the semi-major axis distribution.Comment: 8 pages, 4 figures, accepted for publication in MNRA

    Characterization of a disease-associated mutation affecting a putative splicing regulatory element in intron 6b of the cystic fibrosis transmembrane conductance regulator (CFTR) gene

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    Cystic fibrosis (CF) is a common recessive disorder caused by >1600 mutations in the CF transmembrane conductance regulator (CFTR) gene. About 13% of CFTR mutations are classified as “splicing mutations,” but for almost 40% of these, their role in affecting the pre-mRNA splicing of the gene is not yet defined. In this work, we describe a new splicing mutation detected in three unrelated Italian CF patients. By DNA analyses and mRNA studies, we identified the c.1002–1110_1113delTAAG mutation localized in intron 6b of the CFTR gene. At the mRNA level, this mutation creates an aberrant inclusion of a sequence of 101 nucleotides between exons 6b and 7. This sequence corresponds to a portion of intron 6b and resembles a cryptic exon because it is characterized by an upstream ag and a downstream gt sequence, which are most probably recognized as 5′- and 3′-splice sites by the spliceosome. Through functional analysis of this splicing defect, we show that this mutation abolishes the interaction of the splicing regulatory protein heterogeneous nuclear ribonucleoprotein A2/B1 with an intronic splicing regulatory element and creates a new recognition motif for the SRp75 splicing factor, causing activation of the cryptic exon. Our results show that the c.1002–1110_1113delTAAG mutation creates a new intronic splicing regulatory element in intron 6b of the CFTR gene exclusively recognized by SRp75

    Unequal Partnerships in Higher Education: Pedagogic Innovations in an Electronics within Physics Degree Course

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    This cross-European research partnership reports on supporting pro-active learning and teaching. The two-part project firstly explored student beliefs about electronics within a physics degree and secondly, the use of peer assessment of a Mathematica notebook to develop understandings of standards and quality. Student beliefs were explored because of the negative perceptions tutors thought students brought to the Engineering course within the Physics degree. The results showed that tutors’ fears were unfounded and that the students were highly motivated. Secondly, through peer assessment of a notebook, students developed critical understandings of standards and quality. Generally, students valued the content support and appreciated both the work of their peer and how this helped their own understanding. Esta investigación realizada por un partenariado transeuropeo se centra en el apoyo proactivo de la enseñanza y el aprendizaje en la educación superior. Este proyecto consta de dos partes. Primero se exploraron las creencias de los estudiantes sobre la electrónica en el grado de Física para, después, usar la evaluación por pares del manual Mathematica para desarrollar la comprensión de los estandares y calidad. Las creencias de los estudiantes se exploraron teniendo en cuenta las percepciones negativas que los tutores pensaban que tenían los estudianties del curso de Ingeniería en el grado de Física. Los resultados destacaron que los miedos de los tutores eran infundados y que los estudiantes se mostraban altamente motivados. Segundo, a través de la evaluación a pares del manual, el alumnado desarrolló una comprensión crítica de los estandares y su calidad. Generalmente, el alumnado valoró el apoyo sobre el contenido y apreció tanto el trabajo de sus compañeros y como éste les había ayudado en su comprensión

    Towards building a standard dataset for Arabic keyphrase extraction evaluation

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    Keyphrases are short phrases that best represent a document content. They can be useful in a variety of applications, including document summarization and retrieval models. In this paper, we introduce the first dataset of keyphrases for an Arabic document collection, obtained by means of crowdsourcing. We experimentally evaluate different crowdsourced answer aggregation strategies and validate their performances against expert annotations to evaluate the quality of our dataset. We report about our experimental results, the dataset features
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