322,903 research outputs found
Quadratic optical frequency combs
No full textWe overview theoretical approaches and experimental advances on temporal soliton and optical frequency comb generation in coherently driven, quadratic nonlinear optical cavities
Constrained optimization of spatial sampling in skeletal soil using EMI data and continuous simulated annealing
No full textMultivariate statistical and geostatistical techniques for redox zonation assessment in a tropical alluvial aquifer
No full textWhen high concentrations of Mn and Fe are detected in groundwater, the redox processes are likely occurring in the aquifer. They are due to organic matter oxidation, which can be naturally present in the solid matrix or released in the aquifer by anthropic activities. Thus, the definition of redox zonation within an aquifer can be an effective tool for the conceptual model refinement in remediation strategies planning. In developing countries, either the incorrect management of wastewaters or the land use distribution can affect the environmental quality of surface-water, creating eutrophication conditions in the main streams. In hydrogeological contexts where a multilayer alluvial aquifer is connected with surface-water, also the groundwater quality degrades and redox processes can occur. This issue complicates the groundwater study, its exploitation for drinking purpose
and its management. The objectives of the study are to investigate the effect of the surface-water/groundwater interactions of San Pedro Sula alluvial aquifer, located in north-western Honduras, on the redox zonation, performing a partition of the aquifer in homogeneous areas.
The datasets available refer to 2 monitoring rounds performed in 2002 (wet and in the dry season) consisting of 94 groundwater samplings. In each sample, chemico-physical parameters (pH, EC, Temp, Turb) and analytes (Na, K, Ca, Mg, HCO3, Cl, SO4, NO3, NH4, PO4, Fe, Mn) have been assessed. To assess hydrogeochemical spatial relationships among the variables involved in the redox processes, a multivariate geostatistical approach was performed, called Factorial cokriging, consisting in three main steps: 1) Gaussian anamorphosis to transform raw variables into Gaussian transformed variables; 2) fitting a Linear Model of Coregionalization, including the variogram models of both direct and cross-variograms; 3) extraction and interpolation of the sets of scale-dependent regionalized factors. The first results show a strong relation of Mn concentration with redox processes, which may be ascribed to the organic matter transfer from heavy polluted surface-water to the aquifer. For Fe, its relation to turbidity can be due to a fine colloidal phase developed when different groundwaters, characterized by distinct redox conditions, mix up in the wells
Le seguenti schede filologiche: Agostino Columbre da San Severo, “Mascalcia” (Bologna BA Inc. 16. F. II. ii; ms. Paris BNF Italiens 2231); Anonimo, “Codice di Maria d’Enghien” (ms. AS Lecce, Dipl., s.s.); Anonimo, “Volgarizzamento del De civitate Dei di S. Agostino” (ms. Paris BNF Italiens 87); Caius Plinius Secundus, “Epistulae et Panegyricus” (ms. Napoli BSOG CF. III 6; Bologna BA Inc. 16. AA. IV. 11); Giovanni Russo di Copertino, “Volgarizzamento del Tresor di Brunetto Latini” (ms. Paris BNF Italiens 440); Guido di Bosco di Nardò, “Volgarizzamento del Confessionale di Sant’Antonino da Firenze” (ms. Paris BNF Italiens 595; Città del Vaticano, BAV Inc. Stamp. Ross. 1035); Maria d’Enghien, “Epistolario” (AD Conversano, Dipl., pergg. 169 A/B, 176 A/B, 179 A/B); Nicola di Nardò, “Volgarizzamento della Bibbia – vol. I” (ms. Paris BNF Italiens 3); Nicola di Nardò, “Volgarizzamento della Bibbia – vol. II” (ms. Paris BNF Italiens 4); Nicolò di Ingegne, “Librecto di pestilencia” (ms. Paris BNF Italiens 455); Rogeri de Pacienza di Nardò, “Balzino – Triunfo – Lettere – Sonetti” (ms. Perugia BC F 27)
No full textNeurochemical and neurobehavioral effects of ganstigmine (CHF2819), a novel acetylcholinesterase inhibitor, in rat prefrontal cortex: An in vivo study
No full textGanstigmine (CHF2819) is a novel, orally active acetylcholinesterase inhibitor that induces a stimulation of brain cholinergic transmission. In vivo studies show that, in rat prefrontal cortex, extracellular acetylcholine (ACh) concentrations are significantly increased either after local (1 and 10 mu M) or oral (1.5 and 3 mg/kg) administration. Moreover, repeated oral treatment (six consecutive days; 3 mg/kg) with ganstigmine significantly increases basal extracellular concentrations of ACh in rat prefrontal cortex. Then, acute ganstigmine administration induces a significant increase in extracellular ACh concentrations (actual values) with respect to the last sample in ganstigmine-treated rats. Concentrations of serotonin (5-HT) and noradrenaline (NA) are not affected by any oral dose of ganstigmine (1.5 and 3 mg/kg) used. Moreover, levels of dopamine (DA) and metabolites are not modified either. Basal extracellular concentrations of 5-HT, NA, DA and metabolites are not affected by repeated (six consecutive days) anstigmine treatment (3 mg/kg). Furthermore, there is no effect of the challenge dose of ganstigmine (3mg/kg) on 5-HT, NA, DA and metabolites levels. Finally, ganstigmine reverses the scopolamine-induced deficits of habituation and non-spatial working memory in rats. Taken together, these findings suggest that ganstigmine appears to be a suitable candidate for the treatment of the cholinergic deficit in patients with Alzheimer's disease. (c) 2007 Published by Elsevier Ltd
Diffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
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
Multivariate geostatistics for assessing and predicting soil compaction
No full textThe aim of this research is to investigate the potential of geostatistical techniques for
understanding and evaluating the spatial variability of soil compaction, caused by the
traffic of agricultural machines and/or the action of tillage implements.
Soil cone penetrometer resistance was measured in a field of inland Sicily, along a
transect of 3 m length, from the soil surface until 70 cm depth.
The 3D mean maps showed a random variation on the surface and a high spatial correlation among penetrometer resistance data measured at different depths. The map corresponding to five tractor passes showed the largest extension of the areas characterised by the highest values of penetrometer resistance.
The probability maps showed that at least 20% of the monitored soil volume can exceed the critical penetrometer resistance for root growth
New insights on advanced redox zonation of aquifers using multivariate geostatistics: the San Pedro Sula case study
No full textThe incorrect land use and wastewater management represent anthropogenic pressures on the environment,
which can create heavy euthrophication conditions in surface-water. When surface-water/groundwater
relationships exist, the organic matter produced in the euthrophicated streams can be transferred into the aquifer,
triggering redox processes (i.e. Terminal Electron Accepting Processes, TEAPs). These hydrogeochemical
processes provoke severe groundwater quality modifications (e.g. Mn and Fe solubilization), that complicate
its exploitation and management. The definition of the redox zonation of aquifers represents an effective tool
for the identification of the pollution sources and for the conceptual model refinement, when remediation
strategies and groundwater management plans need to be implemented.
The study area is the San Pedro Sula aquifer (north-western Honduras), which is a multi-layer alluvial
aquifer characterized by well-known surface-water/groundwater interactions and by heavy euthrophicated
streams. Here, high concentrations of Mn and Fe have been found in the aquifer (Di Curzio et al., 2016).
Although the redox processes are dynamic reactions, the redox zonation is generally aimed to identify
homogenous zones within an aquifer characterized by a predominant TEAP (McMahon & Chapelle, 2008).
To overcome this methodological approach, the Multi-Collocated Factorial Kriging (MCFK) (Sollitto et
al., 2010) has been applied to chemico-physical parameters and analytes, diagnostic of the redox processes
(i.e. temperature, pH, turbidity, Mn, Fe, NO3, NH4, PO4). These parameters have been measured in 93 wells,
both in the wet and dry season. In addition, the distance from the surface-water has been selected as an auxiliary
variable, essential to perform the MCFK, because the eutrophicated streams have been considered one of the
pollution sources.
The MCFK results show a short range variability, highlighting a strong relation between Mn concentrations
and redox processes, due to the organic matter transfer from heavy polluted surface-water to the aquifer.
Simultaneously, the relation between Fe and turbidity can be due to a fine colloidal phase, developed when
different redox conditions of groundwater mix up in the wells. At a wider range, Fe seems to be related with
redox processes, near the other pollution source detected in the northern San Pedro Sula alluvial plain
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