331 research outputs found

    An Empirical Study of Real-World SPARQL Queries

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    Understanding how users tailor their SPARQL queries is crucial when designing query evaluation engines or fine-tuning RDF stores with performance in mind. In this paper we analyze 3 million real-world SPARQL queries extracted from logs of the DBPedia and SWDF public endpoints. We aim at finding which are the most used language elements both from syntactical and structural perspectives, paying special attention to triple patterns and joins, since they are indeed some of the most expensive SPARQL operations at evaluation phase. We have determined that most of the queries are simple and include few triple patterns and joins, being Subject-Subject, Subject-Object and Object-Object the most common join types. The graph patterns are usually star-shaped and despite triple pattern chains exist, they are generally short.Comment: 1st International Workshop on Usage Analysis and the Web of Data (USEWOD2011) in the 20th International World Wide Web Conference (WWW2011), Hyderabad, India, March 28th, 201

    The ultracompact regions G40.54+2.59 and G34.13+0.47: A new detection of compact radio sources

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    We report the detection of three compact (<0.001< 0.001 pc) radio sources (CRSs) at Ka_{a}-band (0.9 cm) in the \uchiirs G040.54+2.59 (two CRSs) and G034.13+0.47 (one CRS). These CRSs have weak flux densities and are located at the center of their respective \uchii regions. We found no clear association between massive ionizing stars and CRSs but some radiative influence on the latter, as suggested by their large emission measures (> 107cm6pc10^7 \mathrm{cm}^{-6}\mathrm{pc}), typical of photo evaporating neutral objects close to or associated with massive stars. Our modelling of G40.54+2.59 shows that their CRSs supply enough ionized material to shape its morphology while significantly extending its observable lifetime. On the other hand, despite the possible relation of the CRS with the large-scale outflow signatures observed in G034.13+0.47, the influence of this CRS on the evolution of the \uchii region is unlikely. Our results show that the presence of CRSs can alleviate the so-called lifetime problem of UCHII regions. Still, to address their dynamical evolution adequately, the scenario must include additional mechanisms like ambient confinement, or the role of the kinematics of their associated stellar objects.Comment: Published in Publications of the Astronomical Society of Japan, Volume 75, Issue 1, February 2023, Pages 90-102, https://doi.org/10.1093/pasj/psac09

    Collision of molecular outflows in the L1448--C system

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    We present a study of the central zone of the star-forming region L1448 at 217--230 GHz (\sim 1.3 mm) using ALMA observations. Our study focuses on the detection of proto-stellar molecular outflows and the interaction with the surrounding medium toward sources L1448--C(N) and L1448--C(S). Both sources exhibit continuum emission, with L1448--C(N) being the brightest one. Based on its spectral index and the associated bipolar outflow, the continuum emission is the most likely to be associated with a circumstellar disk. The 12^{\rm 12}CO(J=2\rightarrow1) and SiO(J= 5\rightarrow4) emissions associated with L1448--C(N) trace a bipolar outflow and a jet oriented along the northwest-southeast direction. The 12^{\rm 12}CO(J=2\rightarrow1) outflow for L1448--C(N) has a wide-open angle and a V-shape morphology. The SiO jet is highly collimated and has an axial extent comparable with the 12^{\rm 12}CO(J=2\rightarrow1) emission. There is not SiO(J= 5\rightarrow4) emission towards L1448--C(S), but there is 12^{\rm 12}CO(J=2\rightarrow1) emission. The observations revealed that the red-shifted lobes of the 12^{\rm 12}CO(J=2\rightarrow1) outflows of L1448--C(N) and L1448--C(S) are colliding. As a result of this interaction, the L1448-C(S) lobe seems to be truncated. The collision of the molecular outflows is also hinted by the SiO(J= 5\rightarrow4) emission, where the velocity dispersion increases significantly in the interaction zone. We also investigated whether it could be possible that this collision triggers the formation of new stars in the L1448--C system.Comment: 11 pages, 7 figures, Accepted for publication in Monthly Notices of the Royal Astronomical Society (MNRAS) DOI: 10.1093/mnras/stad98

    Ultracompact HII regions with extended emission: The complete view

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    \ua9 2019 The Author(s). In this paper, we present the results of a morphological study performed on a sample of 28 ultracompact HII (UC HII) regions located near extended free-free emission, using radio continuum (RC) observations at 3.6 cm with the C and D Very Large Array (VLA) configurations, with the aim of determining a direct connection between them. By using previously published observations in B and D VLA configurations, we compiled a final catalogue of 21 UC HII regions directly connected with the surrounding extended emission (EE). The observed morphology of most of the UC HII regions in RC emission is irregular (single- or multipeaked sources) and resembles a classical bubble structure in the Galactic plane with well-defined cometary arcs. RC images superimposed on colour composite Spitzer images reinforce the assignations of direct connection by the spatial coincidence between the UC components and regions of saturated 24 μm emission. We also find that the presence of EE may be crucial to understand the observed infrared excess because an underestimation of ionizing Lyman photons was considered in previous works (e.g. Wood & Churchwell; Kurtz, Churchwell & Wood)

    Editorial charters and newsroom councils in mewdia corporations: a view from the perspective of corporate social responsability

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    Editorial charters and professional representation groups in media corporations are major self regulatory tools often cited in the Spanish literature on journalism ethics and deontology, yet many corporations lack them and they are largely invisible to the public with only a few exceptions, such as the Newsroom Council of the Spanish public national television network TVE. This limited implementation contrasts with the increasing number of media corporations that have adopted corporate social responsibility (CSR) policies that should take into account the expectations of journalists as internal stakeholders. The present study examines the relationships between editorial management and CSR management as a possible approach to integrating corporate governance and news governance in media corporations. The study is based on in depth interviews of members of newsroom councils in Spanish media companies. Discourse analysis of these interviews indicates that journalists in media organizations do not consider that their companies’ CSR policies take into account their professional expectations, in the sense that journalists in these corporations do not perceive news governance and CSR management to be aligned. At the same time, the precarious labor market has led many journalists to stand up less to their employers on questions related to journalism standards. Nevertheless, many newsroom councils are effective at communicating complaints, violations and recommendations to corporate governance bodies

    Necrotoxigenic Escherichia coli from sheep and goats produce a new type of cytotoxic necrotizing factor (CNF3) associated with the eae and ehxA genes

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    Fecal samples from sheep and goats were screened by tissue-culture assays and PCR for the presence of necrotoxigenic Escherichia coli (NTEC) producing cytotoxic necrotizing factors (CNFs). Of the 18 NTEC strains assayed, four were positive for the cnf1 gene while 14 strains were negative for the cnf1 and cnf2 genes. All of the NTEC strains had the eae gene and most of them also carried the ehxA gene. Moreover, all the cnf1– cnf2– NTEC strains were negative for several virulence markers associated with CNF1+ or CNF2+ strains. The cnf gene present in one of these strains was sequenced and analysis of the gene product revealed a new type of CNF, which was named CNF3 (and the coding gene cnf3). Oligonucleotide primers were designed to PCR-amplify a fragment of cnf3. The results showed that all strains examined in this study, except one cnf1+strain, were cnf3+. The association of cnf3 with eae and ehxA suggests that cnf3+ NTEC strains might be pathogenic for humans. [Int Microbiol 2007; 10(1):47-55

    Effects of Extending Milk Replacer Feeding during the Fattening Period on the Behaviour and Welfare of Lambs: A Preliminary Study

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    There is a lack of information on the behavioural and welfare effects of sustaining artificial milk feeding in fattening lambs. Therefore, the present work aimed to study the effects of prolonged artificial milk feeding during fattening with a high concentrate diet on the behaviour of lambs. The behaviour of 16 non castrated male lambs of the Manchega sheep breed (eight lambs were in the group that were fed daily a bottle of milk, and the other eight were in the weaned group) was recorded with four fixed cameras just before bottle feeding (~8:30 a.m.) of the unweaned group till four hours later, every day for 7 weeks. The solid diet (pelleted concentrate plus cereal straw) and housing conditions were the same in both groups. Solid feeds were offered ad libitum. There were no differences between groups in time spent eating nor in drinking, playing, scratching and oral activity behaviours (p > 0.05), but resting episodes were longer in weaned lambs (p < 0.05). Weaned lambs presented a higher frequency of self-grooming behaviour (p < 0.05), while the unweaned group performed a higher frequency of interaction behaviour (p < 0.05). In conclusion, the behaviours of lambs that were fed daily a bottle of milk during the fattening period did not substantially differ from the weaned individuals

    Unsupervised method to classify PM10 pollutant concentrations

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    In this paper a method based mainly on Data Fusion and Artificial Neural Networks to classify one of the most important pollutants such as Particulate Matter less than 10 micrometer in diameter (PM10) concentrations is proposed. The main objective is to classify in two pollution levels (Non-Contingency and Contingency) the pollutant concentration. Pollutant concentrations and meteorological variables have been considered in order to build a Representative Vector (RV) of pollution. RV is used to train an Artificial Neural Network in order to classify pollutant events determined by meteorological variables. In the experiments, real time series gathered from the Automatic Environmental Monitoring Network (AEMN) in Salamanca Guanajuato Mexico have been used. The method can help to establish a better air quality monitoring methodology that is essential for assessing the effectiveness of imposed pollution controls, strategies, and facilitate the pollutants reduction

    The FASTK family of proteins: emerging regulators of mitochondrial RNA biology

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    Abstract The FASTK family proteins have recently emerged as key post-transcriptional regulators of mitochondrial gene expression. FASTK, the founding member and its homologs FASTKD1–5 are architecturally related RNA-binding proteins, each having a different function in the regulation of mitochondrial RNA biology, from mRNA processing and maturation to ribosome assembly and translation. In this review, we outline the structure, evolution and function of these FASTK proteins and discuss the individual role that each has in mitochondrial RNA biology. In addition, we highlight the aspects of FASTK research that still require more attention
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