186,605 research outputs found
Lacalamita, M., Mesto, E., Mongelli, G., Mameli, P., Cerri, G., Pinto, D., Buccione, R., Schingaro, E. 2023. Characterization of Red Muds as valuable resource for sustainability. Convegno Nazionale Italiano sui Geopolimeri. Bari February, 16-17 2023.
No full textA new application of SIMS to the analysis of nitrogen in mica minerals: tobelite.
No full textMuscovite, KAl2[AlSi3O10](OH)2, is a common rock-forming mineral in igneous and
metamorphic-rocks, sediments, hydrothermal alteration and ore deposits. The site between two
adjacent T-O-T (tetrahedral-octahedral-tetrahedral) layers is shared between K and NH4 in any
proportion leading to the building of the “ammonium micas”. Mica with: (i) NH4>K,
□ (vacancy); (ii) Si ≥ 3 apfu (atoms per formula unit); (iii) layer charge (T-O-T) less than one,
is named tobelite [Brigatti M F and Guggenheim S 2002 Rev. Mineral. Geochem. 46 1-97].
The NH4-analog of muscovite, i.e., tobelite, has been predominantly associated to two distinct
geological settings: a) diagenetic to low grade metamorphic shales from meta- anthracite and
anthracite coal fields; b) hydrothermal areas alteration [Ruiz Cruz M D and Sanz de Galdeano
C 2010 Clays Clay Miner. 58 558-572].
In this work three crystals labelled Tob_M2, Tob_M3, Tob_3 were investigated by electron
probe microanalysis (EPMA) in terms of major constituents, and in terms of nitrogen by
secondary ion mass spectrometry (SIMS) in order to gain information on the presence and
amount of NH4. Nitrogen was detected as secondary positive ions by means of a Cameca IMS
4f ion microprobe installed at CNR-IGG, Pavia. SIMS analysis on 14N+ was performed with
16O- primary beam at a mass resolution (M/ΔM) of ~ 1250 required to discriminate the 28Si2+
and 12CH2
+ interferences at the nominal mass number 14 (a.m.u.).
In spite of the severe inhomogeneity of nitrogen in each crystal, the SIMS data put Tob_M2 as
the N-richest crystal of the set. The crystal, analyzed at different spots, is characterized by an
ion signal in the range 399 - 560 (c/s). For Tob_M3 the 14N+ average ion signal is 91 (c/s). In
Tob_3 the N content is likely the lowest in the sample set with an average count rate of
61 (c/s).
The lack of calibration standards did not allow so far to obtain quantitative results for N at the
ion microprobe. Nevertheless, our SIMS data agree qualitatively with constraints derived from
EPMA and charge-balance crystal chemical considerations, and point out that the ion probe is a
valuable tool for the investigation of N in mica minerals
Buccione R., Cerri G., Cisullo C., Lacalamita M., Mameli P., Mesto E., Mongelli G., Pinto D. & Schingaro E. 2023. Geochemistry and mineralogy of bauxite residues (red muds) from Porto Vesme (Sardinia): from disposal material to new resource. Congresso congiunto SIMP-SGI-SOGEI-AIV “The Geoscience paradigm: resources, risk and future perspectives”, 19-21 Settembre 2023, Potenza.
No full textBiological and environmental factors affecting the survival of Otodectes cynotis (Acarina, Psoroptidae) off the host in natural and laboratory conditions
No full textOtodectes cynotis (Acari: Psoroptidae): examination of survival off-the-host under natural and laboratory conditions
No full textThe biological and environmental factors affecting survival off-the-host of Otodectes cynotis (Acari: Psoroptidae) ear mites were investigated under natural and laboratory conditions. From November 2000 to November 2002 mites were collected monthly from cats and divided into four groups according to sex and stage. In laboratory conditions, the mites were placed in an incubator with a steady 95% relative humidity (r.h.), a 10 degrees C. All the plates were examined by stereomicroscopy every 24 h until all the mites had died. The data were analysed statistically by multiple linear regression and survival analysis. At 10 degrees C, the maximum survival time of mites was between 15 and 17 days, while at 34 degrees C, it was between 5 and 6 days. The maximum survival time of adult females was significantly longer than that of other stages. No differences were observed in maximum survival times of mites that had been offered food and those that had not, or in the time (in days) to reach 50% mortality (LT50). When exposed to environmental conditions, the maximum survival time (12 days) was observed at temperatures ranging from 12.3 to 14.2 degrees C and r.h.s between 57.6 and 82.9%. Multiple regression analysis showed that temperature alone influenced the maximum survival time and LT50 of mites, and that the rate of survival declined linearly with increasing mean temperature. This basic understanding of off-host survival suggests that, places which have been inhabited by infected animals may need to be disinfected or remain vacated for at least 12 days before occupancy by clean cats or dogs
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe 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
Catalytic Alcohol oxidation using Cationic Schiff based manganese III complexes with flexible diamino bridge
No full textFour Schiff base manganese(III) complexes with derivatives of [(R,R)-N,N’-bis(salicy1idene)-1,2-cyclohexanediaminato)] including substituents on salicylaldehyde such as 3-methoxy, 3,5-di-tert-butyl and 3,5-chloro were synthesized and characterized using a combination of IR, UV-Vis, and HR ESI-MS techniques and, in one case, XRD. The catalytic activity of these complexes was tested in the oxidation of 1-phenylethanol to acetophenone, revealing very good performances for all of the four manganese complexes. The catalytic reactions were carried out in the presence of tert-butyl hydroperoxide (TBHP) as oxidant and imidazole as co-catalyst. Complex Mn-4, bearing electron withdrawing [(R,R)-N,N’-bis(3,5-di-chloro-salicylidene)-1,2-cyclohexanediaminato)] ligand was found to be the most stable of the tested Mn(III) complexes and was selected for the oxidation of several primary and secondary alcohols
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