270 research outputs found
Cryogenic silicon detectors with implanted contacts for the detection of visible photons using the Neganov-Luke Effect
There is a common need in astroparticle experiments such as direct dark
matter detection, 0{\nu}\b{eta}\b{eta} (double beta decay without emission of
neutrinos) and Coherent Neutrino Nucleus Scattering experiments for light
detectors with a very low energy threshold. By employing the Neganov-Luke
Effect, the thermal signal of particle interactions in a semiconductor absorber
operated at cryogenic temperatures, can be amplified by drifting the
photogenerated electrons and holes in an electric field. This technology is not
used in current experiments, in particular because of a reduction of the signal
amplitude with time which is due to trapping of the charges within the
absorber. We present here the first results of a novel type of Neganov-Luke
Effect detector with an electric field configuration designed to improve the
charge collection within the semiconductor.Comment: 6 pages, 5 figures, submitted to Journal of Low Temperature Physic
Fast, Linear Time Hierarchical Clustering using the Baire Metric
The Baire metric induces an ultrametric on a dataset and is of linear
computational complexity, contrasted with the standard quadratic time
agglomerative hierarchical clustering algorithm. In this work we evaluate
empirically this new approach to hierarchical clustering. We compare
hierarchical clustering based on the Baire metric with (i) agglomerative
hierarchical clustering, in terms of algorithm properties; (ii) generalized
ultrametrics, in terms of definition; and (iii) fast clustering through k-means
partititioning, in terms of quality of results. For the latter, we carry out an
in depth astronomical study. We apply the Baire distance to spectrometric and
photometric redshifts from the Sloan Digital Sky Survey using, in this work,
about half a million astronomical objects. We want to know how well the (more
costly to determine) spectrometric redshifts can predict the (more easily
obtained) photometric redshifts, i.e. we seek to regress the spectrometric on
the photometric redshifts, and we use clusterwise regression for this.Comment: 27 pages, 6 tables, 10 figure
Diagnostic classification of childhood cancer using multiscale transcriptomics
The causes of pediatric cancersâ distinctiveness compared to adult-onset tumors of the same type are not completely clear and not fully explained by their genomes. In this study, we used an optimized multilevel RNA clustering approach to derive molecular definitions for most childhood cancers. Applying this method to 13,313 transcriptomes, we constructed a pediatric cancer atlas to explore age-associated changes. Tumor entities were sometimes unexpectedly grouped due to common lineages, drivers or stemness profiles. Some established entities were divided into subgroups that predicted outcome better than current diagnostic approaches. These definitions account for inter-tumoral and intra-tumoral heterogeneity and have the potential of enabling reproducible, quantifiable diagnostics. As a whole, childhood tumors had more transcriptional diversity than adult tumors, maintaining greater expression flexibility. To apply these insights, we designed an ensemble convolutional neural network classifier. We show that this tool was able to match or clarify the diagnosis for 85% of childhood tumors in a prospective cohort. If further validated, this framework could be extended to derive molecular definitions for all cancer types
Cultural and Media Identity Among Latvian Migrants in Germany
This chapter explores how transnational media and culture impacts on the identity formation of recent Latvian migrants in Germany. In the context of the EU, Germany opened its labour market to the new EU countries rather late, when compared to other âoldâ EU countries. This has had an effect on the composition of the group of Latvian migrants going to Germany, and their identities. In the light of this, this chapter examines how Latvian migrants in Germany feel and experience their belonging to Latvia and its culture. It analyses the social and communicative practices crucial for the development of belonging, including the rootedness in the country where they live and the cultural references that are important for them. The evidence for the analysis in this chapter comes from in-depth interviews, open media diaries and network maps of Latvian migrants in Germany. The chapter situates the description of evidence in the framework of cultural identity concepts and discusses the role of culture and media in the process of building migrant identity. The chapter argues that culture is shaping the transnational self-perception of Latvian migrants in Germany â as it provides collective narratives of imagined common frames of references, and confirms feelings of belonging and distinction
Gene profiling of the erythro- and megakaryoblastic leukaemias induced by the Graffi murine retrovirus
<p>Abstract</p> <p>Background</p> <p>Acute erythro- and megakaryoblastic leukaemias are associated with very poor prognoses and the mechanism of blastic transformation is insufficiently elucidated. The murine Graffi leukaemia retrovirus induces erythro- and megakaryoblastic leukaemias when inoculated into NFS mice and represents a good model to study these leukaemias.</p> <p>Methods</p> <p>To expand our understanding of genes specific to these leukaemias, we compared gene expression profiles, measured by microarray and RT-PCR, of all leukaemia types induced by this virus.</p> <p>Results</p> <p>The transcriptome level changes, present between the different leukaemias, led to the identification of specific cancerous signatures. We reported numerous genes that may be potential oncogenes, may have a function related to erythropoiesis or megakaryopoiesis or have a poorly elucidated physiological role. The expression pattern of these genes has been further tested by RT-PCR in different samples, in a Friend erythroleukaemic model and in human leukaemic cell lines.</p> <p>We also screened the megakaryoblastic leukaemias for viral integrations and identified genes targeted by these integrations and potentially implicated in the onset of the disease.</p> <p>Conclusions</p> <p>Taken as a whole, the data obtained from this global gene profiling experiment have provided a detailed characterization of Graffi virus induced erythro- and megakaryoblastic leukaemias with many genes reported specific to the transcriptome of these leukaemias for the first time.</p
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Results of the Ontology Alignment Evaluation Initiative 2021
The Ontology Alignment Evaluation Initiative (OAEI) aims at comparing ontology matching systems on precisely defined test cases. These test cases can be based on ontologies of different levels of complexity and use different evaluation modalities (e.g., blind evaluation, open evaluation, or consensus). The OAEI 2021 campaign offered 13 tracks and was attended by 21 participants. This paper is an overall presentation of that campaign
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