1,721,090 research outputs found
Molecular structure of the rDNA intergenic spacer (IGS) in Triturus: implications for the hypervariability of rDNA loci
No full textRibosomal DNA (rDNA) variation in the species Triturus vulgaris meridionalis (Amphibia, Urodela) is remarkable because of unusually high intraspecific variability in the number and distribution of ribosomal loci in the karyotype; in addition, portions of the intergenic spacer (IGS) are clustered at chromosomal loci where they are not associated with ribosomal 18S and 28S RNA genes. These clusters are referred to as extraribosomal, and they appear to consist mostly of repetitive BamHI elements. In this paper, we report the complete nucleotide sequence of an IGS of T. v. meridionalis; this structural analysis is aimed to get insight into the molecular mechanism(s) of spreading of the ribosomal cistrons as well as its possible functional significance. We found that the IGS of T. vulgaris has a modular structure: modular repetitive elements contain sequences possibly related to the regulation of transcription of the ribosomal units. In particular, both ribosomal and extraribosomal IGS elements contain presumptive enhancers. Interestingly, the enhancer-containing region is mostly conserved between ribosomal and extraribosomal elements, while mutations accumulate in a region characterized by repetitions of a simple sequence motif, that we consider as a possible recombination hotspot. Our data suggest that extraribosomal elements most probably originated from ribosomal enhancer-containing elements able to move independently from the ribosomal unit at novel chromosomal positions, perhaps with the aid of the simple repetitive motif. We argue that a similar mechanism may lead to the spreading of complete repetition units as well, giving rise to multiple, and variable, ribosomal sites. We propose that hypervariability in the number and distribution of the rDNA loci, as seen in T. vulgaris, is a further mechanism to ensure redundancy, which seems to be an intrinsic property of rDNA biology, the occurrence of IGS elements independently clustered at separate chromosomal loci being a by-product of this mechanism
Artificial neural network for the thermal comfort index prediction: Development of a new simplified algorithm
No full textA simplified algorithm using an artificial neural network (ANN, a feed-forward neural network) for the assessment of the predicted mean vote (PMV) index in summertime was developed, using solely three input variables (namely the indoor air temperature, relative humidity, and clothing insulation), whilst low air speed (<0.1m/s), a minimal variation of radiant temperature (25.1 °C ± 2 °C) and steady metabolism (1.2 Met) were considered. Sensitivity analysis to the number of variables and to the number of neurons were performed. The developed ANN was then compared with three proven methods used for thermal comfort prediction: (i) the International Standard; (ii) the Rohles model; (iii) the modified Rohles model. Finally, another network able to predict the indoor thermal conditions was considered: The combined calculation of the two networks was tested for the PMV prediction. The proposed algorithm allows one to better approximate the PMV index than the other models (mean error of ANN predominantly in ±0.10-±0.20 range). The accuracy of the network in PMV prediction increases when air temperature and relative humidity values fall into 21-28 °C and 30-75% ranges. When the PMV is predicted by using the combined calculation (i.e., by using the two networks), the same order of magnitude of error was found, confirming the reliability of the networks. The developed ANN could be considered as an alternative method for the simplified prediction of PMV; moreover, the new simplified algorithm can be useful in buildings' design phase, i.e., in those cases where experimental data are not available
Energy and environmental effects of human habits in residential buildings due to covid-19 outbreak scenarios in a dwelling near rome
Full text linkThe COVID-19 pandemic and resulting containment measures have shown that energy consumption in buildings is linked to several factors, such as living habits, occupancy profiles, and heating ventilation and air conditioning (HVAC) systems. This paper addresses the influences of such factors on energy consumption in a residential building, analysing different scenarios (pre-COVID-19, lockdown, post-COVID-19), in terms of discomfort and energy needs, through the new hourly calculation method (UNI EN ISO 52016). Energy and environmental effects were studied in a real case study near Rome by varying occupancy profiles, lighting and appliance schedules, and HVAC systems. Results show that, during the heating period, the lockdown scenario led to the lowest hours of discomfort (−29% on average), but the highest in the cooling period (up to +154%, +28% on average). The same scenario led to reasonable reduction of energy needs for heating (−14%), but also highlighted a significant increase (+60%) for the cooling period. This study underlines how the pandemic has influenced the energy and environmental behaviours in buildings. Moreover, the new hourly calculation method points out the importance of analysing HVAC systems, in terms of hours of discomfort, which could provide results that are more reliable
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Retrofit of historic building's power consumption and opportunities of renewable system application: a case study
No full textVariations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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