1,721,122 research outputs found
ROLE OF NF-Y TRANSCRIPTION FACTORS IN ARABIDOPSIS EMBRYO DEVELOPMENT
Full text linkNuclear factor Y (NF-Y) is a trimeric transcription factor composed of three distinct subunits called NF-YA, NF-YB and NF-YC. In Arabidopsis thaliana, NF-Y subunits are known to play roles in many processes, such as embryogenesis, drought resistance, ABA signaling, flowering time, primary root elongation, Endoplasmic Reticulum (ER) stress response and blue light responses. Here, we report that the closely related NF-YA3 and NF-YA8 play an important role in Arabidopsis embryogenesis. Detailed GUS and in situ analyses showed that NF-YA3 and NF-YA8 are expressed in vegetative and reproductive tissues with the highest expression being during embryo development from the globular to the torpedo embryo stage. Plants from the nf-ya3 and nf-ya8 single mutants do not display any obvious phenotypic alteration, whereas nf-ya3 nf-ya8 double mutants are embryo lethal. Morphological analyses showed that the nf-ya3 nf-ya8 embryos are arrested at the globular stage and that both proembryo and suspensor are characterized by a disordered cell cluster with an irregular shape, suggesting defects in the determination of the apical-basal embryo axis. The suppression of both NF-YA3 and NF-YA8 gene expression by RNAi experiments resulted in defective embryos that phenocopied the nf-ya3 nf-ya8 double mutants, whereas complementation experiments partially rescued the globular-arrested nf-ya3 nf-ya8 embryos, confirming that NF-YA3 and NF-YA8 are required in early embryogenesis. Finally, the lack of GFP expression of the auxin responsive DR5rev::GFP marker line in double mutant embryos suggested that mutations in both NF-YA3 and NF-YA8 affect auxin transport in early developing embryos. Our findings indicate that NF-YA3 and NF-YA8 are functionally redundant regulators of the globular-heart transition that marks the acquisition of axiality during embryo development in Arabidopsis thaliana
G. Hérail, M. Fornari. Gisements alluviaux d'or/ Alluvial gold placers/ Yacimientos aluviales de oro, Actes du Symopsium International sur les Gisements Alluviaux d'Or, La Paz, Bolivie 3-5 juin 1991, Ed. ORSTOM, La Paz, 1991
No full textLa Riva Sánchez Juan. G. Hérail, M. Fornari. Gisements alluviaux d'or/ Alluvial gold placers/ Yacimientos aluviales de oro, Actes du Symopsium International sur les Gisements Alluviaux d'Or, La Paz, Bolivie 3-5 juin 1991, Ed. ORSTOM, La Paz, 1991. In: Bulletin de l'Institut Français d'Études Andines, tome 21, N°1, 1992. pp. 402-403
Plasma Transferred Arc deposition of powdered high performances alloys: process parameters optimisation as a function of alloy and geometrical configuration
No full textThe deposition of high wear- and corrosion-resistant alloys through Plasma Transferred Arc (PTA) is an easily automated process combining the possibility to obtain very thick coatings with high deposition speeds, low thermal distortion of the part and negligible dilution levels, thanks to a very high energy-concentration [S. Kalpakjian, S.R. Schmid, Manufacturing Engineering and Technology-4th edition, Addison-Wesley Publishing, 2001, p. 789-790, Scripta Materialia 37 (1997) 721, Applied Surface Science 201 (2002) 154, Surface and Coatings Technology 71 (1995) 196, Journal of Materials Processing Technology 128 (2002) 169, M. Bonacini, Plasma ad arco trasferito per riporti saldati con superleghe in polvere, Saldatura e taglio termico verso il 2000 IIS Meeting, October 3rd 1998, Milan-Italy, Wear 250 (2001) 611, Wear 249 (2002) 846, Composites Science and Technology 58 (1998) 299]. Literature studies regard mostly wear or high temperature behaviour of the deposited alloys and plasma hardening treatment without powder [Applied Surface Science 201 (2002) 154, Surface and Coatings Technology 71 (1995) 196, Journal of Materials Processing Technology 128 (2002) 169, M. Bonacini, Plasma ad arco trasferito per riporti saldati con superleghe in polvere, Saldatura e taglio termico verso il 2000 IIS Meeting, October 3rd 1998, Milan-Italy, Wear 250 (2001) 611, Surface and Coatings Technology 106 (1998) 156, Wear 249 (2002) 846, Surface and Coatings Technology 92 (1997) 157, Wear 181-183 (1995) 8 10, Wear 225-229 (1999) 1114], rather than an optimisation of process parameters, also in critical geometric configurations. An experimental campaign has been carried out on the deposition of two nickel- and a cobalt-base superalloys: Hastelloy 276, Inconel 625 and Stellite 6. Benchmarks of C-Mn steel have been chosen to test geometrical configurations that are critical for the application (corners and grooves). Specimen characterisation through liquid penetration inspection, optical- and scanning electron microscopy and microhardness tests proved that process parameters optimisation depends only on the geometrical configuration and not on the deposited alloy. This result suggests the importance of an accurate design of the reciprocal positioning and movement between the torch and the part to be coated, as a function of the deposition geometry
Natchev auto-traction for lumbago-sciatica: effectiveness in lumbar-disk herniation
No full textIn Lind's auto-traction (LAT) for lumbago-sciatica, the patient provides traction force by pulling with the arms on a specially designed table, which also allows painless mobilization of the lumbar spine and passive traction. Two studies reported that one to 15 one-hour sessions on successive days might be sufficient to relieve pain in 25% to 90% of cases with verified lumbar disc herniation. Unfortunately, the technique imposes tiring manual efforts on the therapist and requires that the patient be transported by ambulance and confined to bed for a long time. These inconveniences were removed in a new version of the treatment proposed by Natchev. The effectiveness of Natchev's auto-traction (NAT) was evaluated in an open prospective trial on 77 patients with chronic lumbago-sciatica refractory to previous therapies, and herniation of one or more lumbar discs verified by computed tomography (CT) or myelography. Thirty-six of the 77 patients (47%) responded to the treatment in three to ten (median = 5) half-hour sessions. Pain intensity dropped to 27% (median) of the pretreatment intensity. Six months after treatment, 28 of the 36 responders were stable; only four had undergone surgery. By contrast, 20 of the 41 nonresponders had been operated on. The severity of either the radiologic or the neurologic picture was not predictive of the outcome. NAT was as effective as LAT: thus, due to its greater convenience it appears to be suitable as a routine approach in lumbar disc herniation and as a screening technique before surgery
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
Variations 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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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