Search results for "Marsh"

An appraisal of Piero Sraffa's 'The Laws of Returns under Competitive Conditions'

2001

The paper proposes a new interpretation of Sraffa's 1926 Economic Journal article, ‘The Laws of Returns under Competitive Conditions’, according to which the latter derives from the same strategy of research which underlies its 1925 Italian precursor, ‘Sulle relazioni fra costo e quantità prodotta’. Sraffa tested the explanatory power of a Marshallian monopolistic partial equilibrium model and concluded that that model is able to treat one source of variable returns (firm-internal economies); but this articulation of Marshall‘s theory does not substantially improve on the trade-off between logical consistency and empirical relevance which afflicted the theory in its whole. © 2001, Taylor & …

Maximum flood area during MIS 1 in the Almenara marshland (Western Mediterranean): Benthic foraminifera and sedimentary record

2018

The sedimentological and micropaleontological analysis of three mechanical cores in the marshland of Almenara (Valencian Community, Spain) has allowed the reconstruction of the Holocene evolution of this wetland. The cold and dry 8.2-ka event might be represented in Almenara by a massive carbonate precipitation bed, upon which mid- and late-Holocene sediments were subsequently deposited. The direct influence of sea-level changes has been recorded in the two cores (S-4 and S-5) located near the marsh barrier, at 400–450 m from the current coastline. The maximum flood area during MIS 1 (last 11,600 years) is represented in these cores by sediments indicative of different littoral subenvironm…

Evidence for Holocene sea level and climate change from Almenara marsh (western Mediterranean)

2017

AbstractIn the Almenara marsh (western Mediterranean), four cores were analyzed to establish the relationship between the marsh record of the Almenara marshlands and the environmental factors responsible for its evolution during the Holocene. One hundred and eighty-six samples were collected for sedimentologic and paleontological study: 63 for biomarker analysis; 5 for amino acid racemization (AAR) dating; and 5 for 14C dating. Litho and biofacies analyses identified distinct paleoenvironments, with the presence of a marsh environment alternating with inputs of alluvial material and marine sediments. Biomarkers indicated the constant presence of terrestrial (herbaceous) plants, together wit…

Presence of pharmaceuticals and heavy metals in the waters of a Mediterranean coastal wetland: Potential interactions and the influence of the enviro…

2015

The occurrence of 17 relevant pharmaceuticals and 7 heavy metals in the waters of the Pego-Oliva Marsh Natural Park (Valencia Community, Spain) were monitored. Thirty four zones (including the lagoon and the most important irrigation channels), covering the main land uses and water sources, were selected for sampling. Thirty three of them were contaminated with at least one pharmaceutical. Ibuprofen and codeine were the pharmaceuticals more frequently detected, in concentrations between 4.8 and 1.2 ng/L and a maximum of 59 ng/L and 63 ng/L, respectively.Regarding metals, Zn showed values under the detection limit in all the samples, while Cd, Co, Cr, Cu, Ni and Pb were detected at concentra…

Biodiversity impacts by multiple anthropogenic stressors in Mediterranean coastal wetlands

2022

Abstract Mediterranean coastal wetlands are considered biodiversity hot-spots and contain a high number of endemic species. The biodiversity of these ecosystems is endangered by several pressures resulting from agricultural and urban expansion, climate change, and the alteration of their hydrological cycle. In this study we assess the state-of-the-art regarding the impact of several stressor groups on the biodiversity of Mediterranean coastal wetlands (i.e., lagoons, marshes, estuaries). Particularly, we describe the impacts of eutrophication, chemical pollution, invasive species, salinization, and temperature rise, and analyze the existing literature regarding the impact of multiple stress…

Population trends and habitat selection of threatened marsh passerines in a protected Mediterranean wetland

2021

Multi proxy analysis for reconstructing the late Holocene evolution of a Mediterranean Coastal Lagoon: Environmental variables within foraminiferal a…

2020

Abstract This study reconstructs the evolution of foraminiferal assemblages and the environmental variables (type of substrate, content in calcium carbonate and content in organic matter) in the Valencia lagoon (western Mediterranean) in response to changes in the late Holocene. In this area of low tidal range, several multiproxy analyses were carried out to determine which environmental variables influence the distribution of the fossil assemblage, and its association with global, regional or local climatic phenomena. The statistical results show that in environments with higher exposure to marine conditions, the calcium carbonate content is the dominant factor, whereas in more restricted …

Halophytic vegetation and adjoining plant communities in Middle Asia (Pamir-Alai and western Tian Shan)

2021

In this paper, we complete the syntaxonomical scheme for halophytic vegetation and adjoining plant communities of the lowland, montane and alpine zones in the Pamir-Alai and western Tian Shan in Tajikistan and Kyrgyzstan with some remarks on its environmental predictors. A total of 217 relevés were sampled in 2014–2019 using the seven-degree cover-abundance scale of the Braun-Blanquet approach. Modified TWlNSPAN was used to classify plant communities based on species composition. The cover-abundance scale was transformed using the four-step interval scale with cut-off levels at 0%, 5% and 25%. Diagnostic species were identified using the phi coefficient as a fidelity measure. Non-metric Mul…

Integer programming models for the pre-marshalling problem

2019

[EN] The performance of shipping companies greatly depends on reduced berthing times. The trend towards bigger ships and shorter berthing times places severe stress on container terminals, which cannot simply increase the available cranes indefinitely. Therefore, the focus is on optimizing existing resources. An effective way of speeding up the loading/unloading operations of ships at the container terminal is to use the idle time before the arrival of a ship for sorting the stored containers in advance. The pre-marshalling problem consists in rearranging the containers placed in a bay in the order in which they will be required later, looking for a sequence with the minimum number of moves…

Respondent Uncertainty and Ordering Effect on Willingness to Pay for Salt Marsh Conservation in the Brest Roadstead (France)

2017

International audience; This paper explores the potential link between the sensitivity of willingness to pay (WTP) to the order of presenting bid amounts in contingent valuation questions (ordering effect) and respondent uncertainty. The resource being valued is a public project to protect salt marshes against the spread of an invasive aquatic plant in the Brest roadstead (France). Valuation uncertainty is captured through a variant of payment card format where respondents are given the opportunity to report their WTP as either a single value (Option A) or an interval of values (Option B). The ordering effect is tested using both parametric models that ignore and control for the potential s…