Search results for "LUE"
showing 10 items of 8383 documents
Experimental evidence of the long‐term effects of reindeer on Arctic vegetation greenness and species richness at a larger landscape scale
2019
1. Large herbivores influence plant community structure and ecosystem processes in many ecosystems. In large parts of the Arctic, reindeer (or caribou) are the only large herbivores present. Recent studies show that reindeer have the potential to mitigate recent warming-induced shrub encroachment in the Arctic and the associated greening of high-latitude ecosystems. This will potentially have large scale consequences for ecosystem productivity and carbon cycling. 2. To date, information on variation in the interactions between reindeer and plants across Arctic landscapes has been scarce. We utilized a network of experimental sites across a latitudinal gradient in the Scandinavian mountains …
Gauge theory of the long-range proximity effect and spontaneous currents in superconducting heterostructures with strong ferromagnets
2017
We present the generalized quasiclassical theory of the long-range superconducting proximity effect in heterostructures with strong ferromagnets, where the exchange splitting is of the order of Fermi energy. In the ferromagnet the propagation of equal-spin Cooper pairs residing on the spin-split Fermi surfaces is shown to be governed by the spin-dependent Abelian gauge field which results either from the spin-orbital coupling or from the magnetic texture. This additional gauge field enters into the quasiclassical equations in superposition with the usual electromagnetic vector potential and results in the generation of spontaneous superconducting currents and phase shifts in various geometr…
Dynamic goal programming synthetic indicator: an application for water companies sustainability assessment
2018
ABSTRACTThis study proposes to evaluate the sustainability of water companies through time by using a new approach, one that involves a dynamic synthetic indicator derived from goal programming techniques. This dynamic indicator approach incorporates catch-up and innovation indices, which enables one to identify the main factors that drive changes in sustainability through time. We used a case study approach to clarify this dynamic approach by evaluating indicator values from a sample of 129 Portuguese water companies over the 2012 to 2015 time period. For most of the water companies we evaluated, sustainability values changed over time, which illustrates the importance of evaluating dynami…
Modeling the natural gas supply chain for sustainable growth policy
2020
Abstract Natural gas has been used globally as a transitional fuel for supporting a green-energy-supply strategy, which has been questioned for the intermittence and lack of reliability of renewables. This paper proposes a System Dynamics model for assessing alternative security of supply policy along the natural gas value chain. The model incorporates demand, transport, production and reserves of natural gas variables according to a systemic perspective. It also includes a module for evaluating the effect of natural gas price on the demand and supply levels, respectively. Alternative supply policies are evaluated under different scenarios. The chosen case-study focuses on the Colombian nat…
Economic feasibility of stationary electrochemical storages for electric bill management applications: The Italian scenario
2016
Battery energy storage systems (BESSs) are expected to become a fundamental element of the electricity infrastructure, thanks to their ability to decouple generation and demand over time. BESSs can also be used to store electricity during low-price hours, when the demand is low, and to meet the demand during peak hours, thus leading to savings for the consumer. This work focuses on the economic viability of BESS from the point of view of the electricity customer. The analysis refers to a lithium-ion (Li-ion), an advanced lead-acid, a zinc-based, a sodium-sulphur (NaS) and a flow battery. The total investment and replacement costs are estimated in order to calculate the cumulated cash flow, …
Occurrence of antibiotics and antiretroviral drugs in source-separated urine, groundwater, surface water and wastewater in the peri-urban area of Chu…
2020
Recently, there has been an increased interest in bridging the knowledge gap in the occurrence and fate of pharmaceuticals in African urban water cycles. In this study, the occurrence of 7 antibiotics and 3 antiretrovirals in source-separated urine, groundwater, wastewater and surface water of the peri-urban area of Chunga in Lusaka, Zambia, was studied. In groundwater, the pharmaceuticals were only sporadically present with 4 antibiotics and 1 antiretroviral detected. The concentration of the antibiotics ranged from below limit of quantification (<LOQ) to 880 ng/L, with sulfamethoxazole having the highest detection frequency of 42.3%. In the surface water, a comparatively high concentrati…
Improving stock index forecasts by using a new weighted fuzzy-trend time series method
2017
Define a new technical indicator for measuring the trend of the fuzzy time series.Introduce a new weighted fuzzy-trend time series method to forecast stock indices.Compare ex-post performances of weighted FTS methods using stock market indices.Assess statistical significance of ex-post forecast accuracy for weighted FTS methods. We propose using new weighted operators in fuzzy time series to forecast the future performance of stock market indices. Based on the chronological sequence of weights associated with the original fuzzy logical relationships, we define both chronological-order and trend-order weights, and incorporate our proposals for the ex-post forecast into the classical modeling…
Harsanyi Power Solutions for Cooperative Games on Voting Structures
2019
International audience; This paper deals with Harsanyi power solutions for cooperative games in which partial cooperation is based on specific union stable systems given by the winning coalitions derived from a voting game. This framework allows for analyzing new and real situations in which there exists a feedback between the economic influence of each coalition of agents and its political power. We provide an axiomatic characterization of the Harsanyi power solutions on the subclass of union stable systems arisen from the winning coalitions from a voting game when the influence is determined by a power index. In particular, we establish comparable axiomatizations, in this context, when co…
Cross-Layer MAC Protocol for Unbiased Average Consensus Under Random Interference
2019
Wireless Sensor Networks have been revealed as a powerful technology to solve many different problems through sensor nodes cooperation. One important cooperative process is the so-called average gossip algorithm, which constitutes a building block to perform many inference tasks in an efficient and distributed manner. From the theoretical designs proposed in most previous work, this algorithm requires instantaneous symmetric links in order to reach average consensus. However, in a realistic scenario wireless communications are subject to interferences and other environmental factors, which results in random instantaneous topologies that are, in general, asymmetric. Consequently, the estimat…
Dynamic Modeling of Planar Multi-Link Flexible Manipulators
2021
A closed-form dynamic model of the planar multi-link flexible manipulator is presented. The assumed modes method is used with the Lagrangian formulation to obtain the dynamic equations of motion. Explicit equations of motion are derived for a three-link case assuming two modes of vibration for each link. The eigenvalue problem associated with the mass boundary conditions, which changes with the robot configuration and payload, is discussed. The time-domain simulation results and frequency-domain analysis of the dynamic model are presented to show the validity of the theoretical derivation.