306 research outputs found
A detailed study of rainfall in the Roman area in the decade 1992â2001
A study of the rainfall regime in the Roman area over the decade 1992-2001 has been undertaken on using tipping pluviometers data, coming from 23 climatic stations located in Rome and in its surroundings. The time response of the
instruments and the automatic acquisition system ensure a resolution of less than 1 minute, thus offering the possibility of an accurate evaluation of intense and extreme
events. The mean yearly rainfall over the whole decade has been determined for each station, obtaining values between 682 and 870mm/year, with a geographical average of 771 and a standard deviation of 47. A study of the rainfall distribution within the 48 half-hours of the day has been carried out in order to ascertain whether preferred times for rain events exist. The analysis has evidenced that this is the case, with high rainfall rates mostly occurring in the late morning and low rates in the late night. Typical values of the maximum 30-min rainfall ever recorded at any given station oscillate between 25 and almost 60 mm. A separate analysis of rainy and dry days has been carried out on studying the statistics of the time delays between two successive tips of the pluviometer. This allowed a characterization of the intense rains as well as of the droughts: the resulting histograms show the existence of a bimodal distribution explained in terms of two kinds of rain events, intense summer showers and drizzles distributed over the rest of the year. As for the droughts, the longest durations appear to range from one to about seven months. On confining the analysis to the rainy days only, the rain intensity data for each station has been plotted and fitted with a Weibull distribution. The corresponding Weibull parameters, while gathering around common mean values, do not show any recognizable pattern when regressed, for instance, versus the altitude of the station or the distance from the coastline. Last, the likelihood that a day of the year, taken at random, be a rainy day or not has been computed for each station yielding probability values ranging from 0.18 to 0.22
The mitochondrial aminoacyl tRNA synthetases : Genes and syndromes
Mitochondrial respiratory chain (RC) disorders are a group of genetically and clinically heterogeneous diseases. This is because protein components of the RC are encoded by both mitochondrial and nuclear genomes and are essential in all cells. In addition, the biogenesis and maintenance of mitochondria, including mitochondrial DNA (mtDNA) replication, transcription, and translation, require nuclear-encoded genes. In the past decade, a growing number of syndromes associated with dysfunction of mtDNA translation have been reported. This paper reviews the current knowledge of mutations affecting mitochondrial aminoacyl tRNAs synthetases and their role in the pathogenic mechanisms underlying the different clinical presentations
A 27-year review of mergers and acquisitions research in 27 leading management journals
This study contributes to the existing body of knowledge on mergers and acquisitions (M&As) by providing a systematic review of over 500 academic articles across 27 management journals over a 27-year time frame. There appears to be a mixture of empirical and conceptual articles, with a larger proportion being empirical but an increasing number leaning towards a conceptual nature. Our findings show that most studies follow a quantitative approach and use large samples, mostly originating from existing databases. There is an emergence of thematic areas related to the strategic factors influencing M&As, but with the human dimension, gaining increasing attention over time.authorsversionpublishe
Reviewing, indicating, and counting books for modern research evaluation systems
In this chapter, we focus on the specialists who have helped to improve the
conditions for book assessments in research evaluation exercises, with
empirically based data and insights supporting their greater integration. Our
review highlights the research carried out by four types of expert communities,
referred to as the monitors, the subject classifiers, the indexers and the
indicator constructionists. Many challenges lie ahead for scholars affiliated
with these communities, particularly the latter three. By acknowledging their
unique, yet interrelated roles, we show where the greatest potential is for
both quantitative and qualitative indicator advancements in book-inclusive
evaluation systems.Comment: Forthcoming in Glanzel, W., Moed, H.F., Schmoch U., Thelwall, M.
(2018). Springer Handbook of Science and Technology Indicators. Springer Some
corrections made in subsection 'Publisher prestige or quality
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
RNA activation of haploinsufficient Foxg1 gene in murine neocortex
More than one hundred distinct gene hemizygosities are specifically linked to epilepsy, mental retardation, autism, schizophrenia and neuro-degeneration. Radical repair of these gene deficits via genome engineering is hardly feasible. The same applies to therapeutic stimulation of the spared allele by artificial transactivators. Small activating RNAs (saRNAs) offer an alternative, appealing approach. As a proof-of-principle, here we tested this approach on the Rett syndrome-linked, haploinsufficient, Foxg1 brain patterning gene. We selected a set of artificial small activating RNAs (saRNAs) upregulating it in neocortical precursors and their derivatives. Expression of these effectors achieved a robust biological outcome. saRNA-driven activation (RNAa) was limited to neural cells which normally express Foxg1 and did not hide endogenous gene tuning. saRNAs recognized target chromatin through a ncRNA stemming from it. Gene upregulation required Ago1 and was associated to RNApolII enrichment throughout the Foxg1 locus. Finally, saRNA delivery to murine neonatal brain replicated Foxg1-RNAa in vivo
Soil erosion modelling: A global review and statistical analysis
To gain a better understanding of the global application of soil erosion prediction models, we comprehensivelyreviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and2017. We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the re-gions within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv)how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To per-form this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. Theresulting database, namedâGlobal Applications of Soil Erosion Modelling Tracker (GASEMT)â, includes 3030 indi-vidual modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluatedand transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insightsinto the state-of-the-art of soil- erosion models and model applications worldwide. This database intends to sup-port the upcoming country-based United Nations global soil-erosion assessment in addition to helping to informsoil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is anopen-source database available to the entire user-community to develop research, rectify errors, andmakefutureexpansion
Soil erosion modelling: A bibliometric analysis
Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication\u27s CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper
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