Search results for "level"
showing 10 items of 3465 documents
Effect of multiple agricultural stressors on freshwater ecosystems: The role of community structure, trophic status, and biodiversity-functioning rel…
2022
Abstract The toxicity and widespread use of agricultural pesticides threaten freshwater biodiversity, but their long-term effects under different nutrient concentrations are poorly understood. We evaluated the single or combined effects of two pesticides (chlorpyrifos and diuron) under different nutrient regimes (mesotrophic and eutrophic) on community structure and ecosystem functions in replicated pond mesocosms. The individual application of nutrients and pesticides affected community composition and species richness. Ecosystem functioning was generally less sensitive to chemical stress than community structure, while eutrophication fostered the dominance of species that are more resilie…
Investigation of amorphous oxide film-electrolyte junctions by AC techniques
1992
Current AC (alternating current) techniques are used often to characterize the energetics at a semiconducting solid phase/electrolyte interface. For thin layers having a strongly disordered or amorphous structure (such as oxide-passive layers anodically grown on valve metals), interpretative models currently used for crystalline semiconductors may produce misleading data. A new interpretation of the admittance data, based on recent models for amorphous semiconductors (a-Sc) Schottky barriers, is presented for passive films of Nb, W and Ti. The physical bases of the model are presented as well as its advantages and disadvantages. The new theory views the solid/electrolyte interface more sati…
Variation in the stable isotope trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766) from two Mediterranean sites: insights from a g…
2022
A direct consequence of sea warming is the shift in the distribution range of thermo-tolerant species that have the potential to determine novel inter-specific interactions, ultimately altering food web structures and ecosystem processes. In this study, we investigated the trophic position of the bluefish Pomatomus saltatrix (Linnaeus, 1766), a pelagic predator that has recently expanded its distribution in the Mediterranean basin and for which scant information is available on its functional role in recently-colonised areas. Nitrogen and carbon stable isotopes were determined in muscle tissues of bluefish specimens collected in south-east Italy in the Gulf of Taranto (NW Ionian Sea) and in…
Functional spatial contextualisation of the effects of multiple stressors in marine bivalves
2018
Abstract. Many recent studies have revealed that the majority of environmental stressors experienced by marine organisms (ocean acidification, global warming, hypoxia etc.) occur at the same time and place, and that their interaction may complexly affect a number of ecological processes. Here, we experimentally investigated the effects of pH and hypoxia on the functional and behavioural traits of the mussel Mytilus galloprovincialis, we then simulated the potential effects on growth and reproduction dynamics trough a Dynamic Energy Budget (DEB) model under a multiple stressor scenario. Our simulations showed that hypercapnia had a remarkable effect by reducing the maximal habitat size and r…
Level of acceptance of epistemically unwarranted beliefs in pre-service primary school teachers: influence of cognitive style, academic level and gen…
2022
One of the main objectives of scientific literacy is the development of rational skills and critical thinking in citizens. This is a central goal for teachers. However, beliefs that lack rational foundation and supporting evidence, named “epistemically unwarranted beliefs” (EUB), spread rapidly among the population. If teachers had some of these EUB, their work could be compromised. The aim of this research was to determine the level of acceptance of different EUB in Spanish pre-service primary school teachers and to analyze the influence of their cognitive style, gender, and academic level. Two hundred and fifty undergraduate students of Bachelor’s Degree in Primary Education participated …
Two-Player Noncooperative Games over a Freight Transportation Network''
2004
A game between two players acting on the same road transportation network is considered in this paper. The first player aims at minimizing the transportation costs, whereas the second player aims at maximizing her profit (or, in general, her utility) that is proportional to the flow passing through the arcs under her control. We introduce bilevel linear programming formulations for this problem. We derive conditions of existence and properties of the equilibrium points and propose an algorithm finding a local optimal solution. Finally, we present an application of the model to a real system involving trucks travelling through Europe from a Middle Eastern country.
A cross-country study of skills and unemployment flows
2021
AbstractUsing an international survey that directly assesses the cognitive skills of the adult population, I study the relation between skills and unemployment flows across 37 countries. Depending on the specifically assessed domain, I document that skills have an unconditional correlation with the log-risk-ratio of exiting to entering unemployment of 0.65–0.68 across the advanced and skill-abundant countries in the sample. The relation is remarkably robust and it is unlikely to be due to reverse causality. I do not find evidence that this positive relation extends to the seven relatively less advanced and less skill-abundant countries in the sample: Peru, Ecuador, Indonesia, Mexico, Chile,…
The Impact of Coronavirus Disease 2019 Lockdown on Athletes’ Subjective Vitality: The Protective Role of Resilience and Autonomous Goal Motives
2021
The lockdown resulting from coronavirus disease 2019 (COVID-19) has had a huge impact on peoples’ health. In sport specifically, athletes have had to deal with frustration of their objectives and changes in their usual training routines. The challenging and disruptive situation could hold implications for their well-being. This study examined the effect of the COVID-19 lockdown on changes in athletes’ reported eudaimonic well-being (subjective vitality) and goal motives (autonomous and controlled) over time (i.e., pre-lockdown and during lockdown). The relationship of resilience to changes in subjective vitality was also determined, and changes in athletes’ goal motives were examined as pot…
Influence of Training Load on Mood Disturbance at Sea Level and 3900 m Altitude: A Case Study of a Wheelchair Athlete
2018
The purpose of this case study was to investigate the influence of a training load (TL), oxygen saturation (SO2) and blood pressure (BP) on mood states in a wheelchair marathoner during (7 weeks at sea level (SL), 5 weeks at 3860 m altitude, 1 week returning to SL). TL was obtained with Foster’s equation while mood states were obtained with the Profile of Mood States Questionnaire (POMS). Furthermore, SO2 and BP were assessed upon wakening. SO2 (%) decreased at altitude, compared to SL (88.31 ± 2.46 vs. 98.52 ± 0.11) and increased until the last week at altitude (92.64 ± 1.12). Systolic pressure (SP) increased at altitude compared to pre-altitude (126.0 ± 5…
Unsteady State Water Level Analysis for Discharge Hydrograph Estimation in Rivers with Torrential Regime: The Case Study of the February 2016 Flood E…
2017
Discharge hydrograph estimation during floods, in rivers with torrential regime, is often based on the use of rating curves extrapolated from very low stage-discharge measurements. To get a more reliable estimation, a reverse flow routing problem is solved using water level data measured in two gauged stations several kilometers from each other. Validation of the previous analysis carried out on the flood event of February 2016 at the Europa Bridge and Castiglione Scalo sections of the Crati River (Cosenza, Italy) is based on the use of 'soft' discharge measurement data and the comparison of the water level data computed in the downstream gauged section by three different hydraulic models w…