1,721,326 research outputs found
Deposition of sulfur from H2S on porous adsorbents and effect on their mercury adsorption capacity
No full textThe deposition of elemental sulfur on porous adsorbents (commercial pre-sulfurised activated carbons and alumina, an HY zeolite and a selenised adsorbent) has been observed when the adsorbents are exposed to a gaseous stream containing hydrogen sulfide and oxygen. The sulfur deposition from H2S is more marked for the activated carbons and the alumina, it is substantially decreased when zeolite is used, and is practically insignificant for the selenium-based adsorbent. For the pre-sulfurised activated carbons, further sulfur deposition is initially beneficial in terms of increasing their mercury chemisorbing capacity but, subsequently, the structural properties are affected and this results in a drastic reduction in adsorption capacity. Further sulfur deposition on the pre-sulfurised alumina seems immediately to compromise its capacity to chemisorb mercury. The selenium-based adsorbent shows problems with detachment of the fine mercuric selenide powder from the matrix. Sulfur deposition on the initially unsulfurised zeolite improves its mercury adsorption capability. The initially sulfur-free zeolite could be a promising adsorbent for the treatment of this specific type of gas stream. In fact, after a moderate level of sulfur deposition from oxidation of hydrogen sulfide, it can simultaneously chemisorb the mercury vapours by reaction with the sulfur itself while, unlike the activated carbons and alumina, maintaining its required structural properties for a relatively long period
New Routes for Continuous Endovascular Advancement
No full textEndovenous techniques, such as pharmacomechanical
thrombolysis, catheter directed thrombolysis, and mechanical
thrombectomy are being employed increasingly to treat deep
vein diseases, such as thrombosis or post-thrombotic syndrome.
One of the key elements to achieving a high rate of
success is the choice of an appropriate venous access, to
provide a favourable approach the treatment site. In this
context, the popliteal vein is an appropriate site of venous
access for most treatments, given its anatomical position and
calibre. Usually, a percutaneous popliteal venous access is
obtained with the patient prone, under duplex ultrasound
guidance.
Reconstructing the palaeoenvironments of the Early Pleistocene mammal faunas from the pollen preserved on fossil bones
No full textWe carried out a systematic investigation on the pollen content of sediment adhering to skeletal
elements of large mammals which originate from the long lacustrine record of Leffe (Early Pleistocene of
the Italian Alps). Three local faunas were discovered during mining activities along the intermediate part
(spanning from 1.5 to 0.95 Ma) of the basin succession. The excellent pollen preservation allowed testing
the reproducibility of the pollen signal from single skeletons. A clear palaeoenvironmental patterning,
consistent with the ecological preferences of the considered mammal species, emerged from the
canonical correspondence analysis of pollen types diagnostic for vegetation communities. Edaphic
factors related to seasonal river activity changes and to the development of swamp forests in the
riverbanks are significantly associated to the occurrences of Hippopotamus cf. antiquus, whereas finds of
Mammuthus meridionalis belong to fully forested landscapes dominated by conifer or mixed forests of
oceanic, warm to cool-temperate climate. Rhinoceros habitats include variable forest cover under
different climate states. Distinct cool-temperate, partially open vegetation could be recognized for large
deer included Cervalces cf carnutorum.
A palynostratigraphic correlation between individual spectra and a reference palynostratigraphic
record allowed assignment of many fossil remains to a precise stratigraphic position. This procedure also
shown that the Leffe local faunas include specimens accumulated under different environmental and
climate states, as a consequence of high-frequency climate changes characterizing the Late Villafranchian
Early Pleistocene
The palaeoenvironment of Cervalces latifrons (Johnson, 1874) from Fornaci di Ranica (late Early Pleistocene, Northern Italy)
No full textWe compared the pollen content and infrared (IR) spectra of clay extracted from the fossil braincase of a broad-fronted
moose [Cervalces latifrons (Johnson, 1874)] from Fornaci di Ranica (late Early Pleistocene, northern Italy) with the
complete pollen and IR record from the sequence of palustrine–lacustrine sediments at the site. This allowed us to correlate
the remains with a specific pollen zone, characterized by forest retreat and expansion of herbaceous communities. At the time
of Cervalces occurrence around the basin of Fornaci di Ranica, the regional vegetation consisted in scattered conifer forests
with Pinus sylvestris/mugo and dry meadows and/or steppes. Around the basin and along watercourses, the vegetation
probably consisted of moist meadows with forb stands, palustrine herb associations and shallow water communities with
telmatic helophytes. A morpho-functional comparison between living Alces alces and its extinct relative Cervalces latifrons
was carried out, suggesting adaptation to similar marshy habitats, with bushes and strewn debris and similar diet.
Palaeobotanical and palaeontological data from other European sites bearing remains of Cervalces and Alces indicate that
these animals could have lived either in boreal forests and in mixed conifer/deciduous forests and in meadow steppes. Warm temperate deciduous forests seem to be excluded
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
Hydrological consequences of soil surface type and condition in colluvial mica-schist soils after agricultural abandonment
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
- …
