1,720,969 research outputs found
Evolution of fluviokarst canyons in response to the Quaternary tectonic uplift of the Apulia Carbonate Platform (southern Italy): Insights from morphometric analysis of drainage basins
Full text linkThe evolution of fluviokarst landscapes results from the interplay of karst and fluvial processes, all driven by rock uplift or base level fall. The fluviokarst landscape of the Murge Plateau in the central Apulian Region (southeastern Italy) is characterized by narrow, steep-sided, V-shaped canyons, locally called ‘Gravine’, and deeply incised into the Plio-Pleistocene deposits of the Bradanic Trough and the underlying Apulian limestone bedrock. Previous studies propose alternative models of canyons development, however identifying a dominant morphogenetic process for the evolution of the ‘Gravine’ fluviokarst drainage basins remains an open question. The results of our regional morphometric analysis reveal a marked transition from the relict, low-relief landscape preserved in the Murge uplands to the steep channel reaches below prominent knickpoints showing evidence of a transient wave of river incision that is propagating inland. We observe anomalies of mean local relief and channel steepness, and the distribution of fluvial knickpoints consistent with a regional uplift affecting the Murge Plateau since Middle-Late Pleistocene. These findings demonstrate that the history of landscape evolution was dominated by fluvial processes. Using transformed river profile analysis we show that χ anomalies in the ‘Gravine’ trunk channels indicate drainage basin instability by drainage area capture. The convex-shape of the hypsometric curves and high hypsometric integrals confirm that the disequilibrium state of the 13 analyzed basins results from a combination of regional uplift and subsequent river network reorganization and plateau area captures. Based on our results, we propose a new model of landscape evolution for the ‘Gravine’ fluviokarst drainage basins
Chemically functionalized Eggs capsules of Sea Snail (ess) banded dye-murex for bioremediation applications
Full text linkamong materials proposed in literature to remediate the environment, biohybrid composites at the interface between material science, chemistry and biology are the most promising. In this paper, we first contemplate the use of porous capsules, released by marine murex snails after eggs hatching, as a natural matrix capable of adsorbing organic pollutants. This study starts to investigate chemical and morphological features of this envisaging, unexplored protein material. Then, the chemical topography of egg capsules has been potentiated via a surface decoration with the polyphenol gallic acid, leading to enhance the bioremediation potential of the final biohybrid material. This moiety helped to give a huge activation of the adsorption towards a specific organic pollutant: the drug Tetracycline. The bioorganic methodology begins with bioconjugation via direct targeting of the exposed Lysine residues with polyphenol moieties. The material was morphologically investigated via high-resolution X-ray micro-computed tomography (HR X-ray μ-CT), and characterized using Raman spectroscopy, Fourier Transformed Infrared-attenuated total reflectance (FTIR-ATR), micro-IR, elemental, and BET analysis, after the bioorganic decoration. For the in vitro environmental remediation test, Tetracycline was chosen as a model drug molecule, and the specific adsorption was tested concerning the mass of the investigated material, different pH conditions (considering limit values), till evaluating the recycle of the material. The functionalization efficiently sparked the properties of the starting material, leading to an increase in the biosorption of the model urban pharmaceutical pollutant Tetracycline. Compared to the natural material, the functionalized matrix showed a sorbing capacity 12.5 times higher, leading to the sorption of about 25 mmol of Tetracycline per g of sorbent. In addition, the functionalized material remained active up to 5 sorption cycles. This outcome represents an achievement made from the combination of natural materials and Nature inspired molecular moieties to act as efficient platforms for self-cleaning, leading to environmental remediation
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
EGU General Assembly 2016, held 17-22 April, 2016 in Vienna Austria, id. EPSC2016-16813
No full textA new approach to identify contributing fractures and ambient wellbore flow in fractured and karst aquifers is presented. It is time efficient, low cost and based on a benign tracer: the dissolved oxygen (DO). The method was already applied by other scientists to test fractured crystalline rock wells. The DO method consists in elevating water DO concentration in a borehole by bubbling air at assigned water depths using a porous polypropylene tube (bubbler) connected to a compressed air tank with tubing. After the aeration, the resulting profile should be a linear increase in DO with depth due to the effects of water pressure on oxygen solubility. Any changes in the DO profile will be then observed when water flows into and through the well. DO dilution can be used to locate inflowing fractures and to define active flow zones in wells. Where there is no change in the DO profile “dead zones” in the well, where no flow is taking place, can be identified.
The DO tests in this work have been carried out in the industrial area of Bari, at the experimental station of five wells drilled at the CNR-IRSA. The wells penetrate karstic limestone. Results show enhanced flow through at depths between 32 and 37 meters below the water level and connecting patterns between the studied wells.
The benefits of utilizing DO as a tracer include ease of accessibility, low cost and time-efficiency as well as non-toxic nature of the tracer and no impact on flow conditions
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
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