1,990 research outputs found
The (Evolving) vineyard\u2019s age structure in the valencian community, Spain. A new demographic approach for rural development and landscape analysis
Vineyards have assumed a key role as rural landmarks in recent decades. Investigating vineyard dynamics and contexts may reveal various economic, cultural, and environmental aspects of rural landscapes, which can be linked to land-use changes and major soil degradation processes, including soil erosion. As a contribution to rural landscape studies, the purpose of this work is to investigate the spatial distribution of vineyard plots in the Valencian community, located in the eastern area of the Iberian Peninsula, focusing on the final product, the type of vineyard and how long each vineyard has been settled over time. The work provides a comprehensive analysis of a wine-growing landscape, considering strategic (spatial) assets in present and past times. Vineyards were interpreted as a distinctive landmarks that give value to local economies, basic knowledge of how long different types of wine plots have been present in the Valencian community is useful when estimating their degree of sustainability and formulating suggestions, policies, and strategies to prevent processes of landscape degradation at various spatial scales
Industrial sprawl and residential housing. Exploring the interplay between local development and land-use change in the Valencian Community, Spain
Urbanization in Mediterranean Europe has occurred in recent decades with expansion of residential, commercial and industrial settlements into rural landscapes outside the traditional metropolitan boundaries. Industrial expansion in peri-urban contexts was particularly intense in Southern Europe. Based on these premises, this work investigates residential and industrial settlement dynamics in the Valencian Community, Spain, between 2005 and 2015, with the aim to clarify the role of industrial expansion in total urban growth in a paradigmatic Mediterranean region. Since the early 1990s, the Valencian industrial sector developed in correspondence with already established industrial nodes, altering the surrounding rural landscape. Six variables (urban hierarchy, discontinuous settlements, pristine land under urban expansion, isolated industrial settlements, within- and out-of-plan industrial areas) were considered with the aim at exploring land-use change. Empirical results indicate a role of industrial development in pushing urban sprawl in coastal Valencia. A reflection on the distinctive evolution of residential and industrial settlements is essential for designing new planning measures for sustainable land management and containment of urban sprawl in Southern Europe. A comparative analysis of different alternatives of urban development based on quantitative assessment of land-use change provides guidelines for local development and ecological sustainability
A new sauropod titanosaur from the Plottier Formation (Upper Cretaceous) of Patagonia (Argentina)
This paper presents a new titanosaur sauropod, collected from levels of reddish clays assigned to the Plottier Formation (Coniacian-Santonian). The holotype of Petrobrasaurus puestohernandezi gen. et. sp. nov. is a disarticulated specimen, from which teeth, cervical, dorsal and caudal vertebrae, sternal plates, metacarpals, femora, tibia, a fragment of ilium, pubis, haemal arches, and cervical and dorsal ribs have been preserved. This period is of particular interest because it saw the definitive isolation of the vertebrate faunas of Patagonia, with the separation of South America from the rest of Gondwana, a process that had begun during the Early Cretaceous. Although some of the characters observed in Petrobrasaurus gen. nov. suggest a relationship with the South American clade Lognkosauria, this new sauropod is regarded as Titanosauria incertae sedis until a more profound analysis of the Titanosauria that in which it is included is undertaken
A Nexafs Study of Nitric Oxide Layers Adsorbed from a nitrite Solution onto a Pt(111) Surface
NO molecules adsorbed on a Pt(111) surface from dipping in an acidic nitrite
solution are studied by near edge X-ray absorption fine structure spectroscopy
(NEXAFS), X-ray photoelectron spectroscopy (XPS), low energy electron
diffraction (LEED) and scanning tunnelling microscopy (STM) techniques. LEED
patterns and STM images show that no long range ordered structures are formed
after NO adsorption on a Pt(111) surface. Although the total NO coverage is
very low, spectroscopic features in N K-edge and O K-edge absorption spectra
have been singled out and related to the different species induced by this
preparation method. From these measurements it is concluded that the NO
molecule is adsorbed trough the N atom in an upright conformation. The maximum
saturation coverage is about 0.3 monolayers, and although nitric oxide is the
major component, nitrite and nitrogen species are slightly co-adsorbed on the
surface. The results obtained from this study are compared with those
previously reported in the literature for NO adsorbed on Pt(111) under UHV
conditions
Extended Huckel theory for bandstructure, chemistry, and transport. II. Silicon
In this second paper, we develop transferable semi-empirical parameters for
the technologically important material, silicon, using Extended Huckel Theory
(EHT) to calculate its electronic structure. The EHT-parameters areoptimized to
experimental target values of the band dispersion of bulk-silicon. We obtain a
very good quantitative match to the bandstructure characteristics such as
bandedges and effective masses, which are competitive with the values obtained
within an orthogonal-tight binding model for silicon. The
transferability of the parameters is investigated applying them to different
physical and chemical environments by calculating the bandstructure of two
reconstructed surfaces with different orientations: Si(100) (2x1) and Si(111)
(2x1). The reproduced - and -surface bands agree in part
quantitatively with DFT-GW calculations and PES/IPES experiments demonstrating
their robustness to environmental changes. We further apply the silicon
parameters to describe the 1D band dispersion of a unrelaxed rectangular
silicon nanowire (SiNW) and demonstrate the EHT-approach of surface passivation
using hydrogen. Our EHT-parameters thus provide a quantitative model of
bulk-silicon and silicon-based materials such as contacts and surfaces, which
are essential ingredients towards a quantitative quantum transport simulation
through silicon-based heterostructures.Comment: 9 pages, 9 figure
An assessment of emerging networks in the fruit sector: The case of Inca berry in Ecuador
The diversification of agri-food products through emerging chains has a fundamental social and economic role in Ecuador. A substantial amount of research focused only on examining critical factors in terms of agronomic and environmental performance. However, there is a shift in the agri-food chain perspective and study towards more sustainable models of production, logistics trade, and consumption. Aspects such as the socio-economic sustainability, level of collaboration between actors, an adequate chain configuration, and the employment of smart governance mechanisms show the weaknesses where stakeholders can propose enhancements. In this respect, socio-economic and productive factors are consequential and still affecting the progress of these chains. Also, the current growth of market opportunities at the local and international level is a driver to support them by setting sustainable strategies. This study aimed to analyze socio-economic and production aspects to understand the dynamic across the emerging Inca berry (Physalis peruviana) chain located in Ecuador and bring forward potential strategies. Thus, chain vertical and horizontal imensioning was introduced to contribute with relevant insights. The framework applied accounts with a revision of primary and support activities, and flows of high and low relevance. The investigation clustered pre-production, production, and post-production tiers. Also, it executed the food chain mapping, the identification of chain actors, and application of surveys at the supply chain levels to identify strengths and weaknesses based on specific socio-economic and productive variables. Results stated several viable long-term strategies. Examples of those strategies are the diversification of marketing channels, the intervention of academic institutions to improve efficiency, productivity, and the associations' empowerment. All of them aimed at circular economic models. The main research contribution is the application of the chain configuration to assess the chain performance comprehensively. Based on the results, our recommendation is incorporating new indicators to analyze the environmental and institutional components profoundly
Scaling of the buckling transition of ridges in thin sheets
When a thin elastic sheet crumples, the elastic energy condenses into a
network of folding lines and point vertices. These folds and vertices have
elastic energy densities much greater than the surrounding areas, and most of
the work required to crumple the sheet is consumed in breaking the folding
lines or ``ridges''. To understand crumpling it is then necessary to understand
the strength of ridges. In this work, we consider the buckling of a single
ridge under the action of inward forcing applied at its ends. We demonstrate a
simple scaling relation for the response of the ridge to the force prior to
buckling. We also show that the buckling instability depends only on the ratio
of strain along the ridge to curvature across it. Numerically, we find for a
wide range of boundary conditions that ridges buckle when our forcing has
increased their elastic energy by 20% over their resting state value. We also
observe a correlation between neighbor interactions and the location of initial
buckling. Analytic arguments and numerical simulations are employed to prove
these results. Implications for the strength of ridges as structural elements
are discussed.Comment: 42 pages, latex, doctoral dissertation, to be submitted to Phys Rev
Strain-induced Evolution of Electronic Band Structures in a Twisted Graphene Bilayer
Here we study the evolution of local electronic properties of a twisted
graphene bilayer induced by a strain and a high curvature. The strain and
curvature strongly affect the local band structures of the twisted graphene
bilayer; the energy difference of the two low-energy van Hove singularities
decreases with increasing the lattice deformations and the states condensed
into well-defined pseudo-Landau levels, which mimic the quantization of massive
Dirac fermions in a magnetic field of about 100 T, along a graphene wrinkle.
The joint effect of strain and out-of-plane distortion in the graphene wrinkle
also results in a valley polarization with a significant gap, i.e., the
eight-fold degenerate Landau level at the charge neutrality point is splitted
into two four-fold degenerate quartets polarized on each layer. These results
suggest that strained graphene bilayer could be an ideal platform to realize
the high-temperature zero-field quantum valley Hall effect.Comment: 4 figure
Elevated arousal at time of decision-making is not the arbiter of risk avoidance in chickens
The somatic marker hypothesis proposes that humans recall previously experienced physiological responses to aid decision-making under uncertainty. However, little is known about the mechanisms used by non-human animals to integrate risk perception with predicted gains and losses. We monitored the behaviour and physiology of chickens when the choice between a high-gain (large food quantity), high-risk (1 in 4 probability of receiving an air-puff) option (HGRAP) or a low-gain (small food quantity), no-risk (of an air-puff) (LGNAP) option. We assessed when arousal increased by considering different stages of the decision-making process (baseline, viewing, anticipation, reward periods) and investigated whether autonomic responses influenced choice outcome both immediately and in the subsequent trial. Chickens were faster to choose and their heart-rate significantly increased between the viewing and anticipation (post-decision, pre-outcome) periods when selecting the HGRAP option. This suggests that they responded physiologically to the impending risk. Additionally, arousal was greater following a HGRAP choice that resulted in an air-puff, but this did not deter chickens from subsequently choosing HGRAP. In contrast to human studies, we did not find evidence that somatic markers were activated during the viewing period, suggesting that arousal is not a good measure of avoidance in non-human animals
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