1,721,940 research outputs found
A propos de la larve d'Hoplocampa brevis Klug (Hym. Tenthredidae)
No full textd'Aguilar Jacques, Ventura G. A propos de la larve d'Hoplocampa brevis Klug (Hym. Tenthredidae). In: Bulletin de la Société entomologique de France, volume 53 (9-10), Novembre-décembre 1948. pp. 141-143
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
The types of Nummulites and Operculina of the Tellini (1890) collection stored at the Museum of Paleontology at "La Sapienza" University of Rome
No full textA complete, figured type list of the Nummulitid taxa instituted by Tellini and stored at this museum is given as a preliminary contribution towards their critical taxonomical revision
3D imaging technology for improvement of and application in architectural monitoring
No full textWe consider the problem of laser scanners are increasingly being employed as surveying instruments for numerous applications. In this paper we have constructed a system for monitoring dangerous parts of archaeological sites or buildings. In order to the fragile parts of an archaeological site or building are protected without human intervention, the system will perform a 3D scan of the building in real time and collect the data. The system will restore the collected data and monitor the building by comparing and analyzing the data at different times. At the same time, in order to reduce the error generated in the coordinate system transformation process, we have established a “flattened” model to optimize 3D imaging to ensure that the final image does not exhibit distortion. By simulating different data, we can determine that our “flattened” model produces good results in 3D imaging
Crystal fabric evolution in lava flows: results from numerical simulations
No full textThe analysis of the preferred orientation of crystals (crystal fabric) in magmatic rocks has become a widely used technique for the reconstruction of the flow history. However, little is known about the evolution of the fabric during flow. Here, numerical simulations are used to study the fabric evolution of low-concentration, laminar magmatic flows (e.g. lava flows). The fabric evolution of (a) particle populations with a specified shape (cube, tablet, prism, and transitional shape) and (b) crystal populations from a lava flow is analyzed in different flow geometries (simple shear, hyperbolic and pure shear flows) assuming plane strain. Results show that fabric analysis of the whole crystal population gives little information about flow kinematics, whereas the comparative analyses of crystal sub-populations with different shapes allow us to recognize the flow geometry. Simple shear flow produces oscillating to pseudo-stable fabrics. The fabric strength is lower with respect to that of hyperbolic and pure shear flows and the preferred orientation of crystals does not coincide with the flow direction, except for large strain and specified shapes. Sub-fabrics with opposite sense of shear may also develop, depending on the crystal shape and finite strain. Pure shear and hyperbolic flows show stable to pseudo-stable fabrics. The preferred crystal orientation may or may not coincide with the flow direction according to whether flow is in pure or hyperbolic shear. Results from numerical simulations are comparable with those from experimental models and natural examples. The fabric strength depends on the number of crystals and caution must be used in extrapolating the results beyond the scale of observation. The finite strain in a sample from a lava flow from the Aeolian Islands is determined by the comparative analysis of the calculated and measured fabric parameters (fabric intensity and crystal preferred orientation). Criteria to discriminate among fabrics produced by different flow types are also provided
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