Search results for "Study"
showing 10 items of 15483 documents
Why aren't warning signals everywhere? : On the prevalence of aposematism and mimicry in communities
2021
Warning signals are a striking example of natural selection present in almost every ecological community - from Nordic meadows to tropical rainforests, defended prey species and their mimics ward off potential predators before they attack. Yet despite the wide distribution of warning signals, they are relatively scarce as a proportion of the total prey available, and more so in some biomes than others. Classically, warning signals are thought to be governed by positive density-dependent selection, i.e. they succeed better when they are more common. Therefore, after surmounting this initial barrier to their evolution, it is puzzling that they remain uncommon on the scale of the community. He…
Eco-genetics of desiccation resistance in Drosophila.
2021
International audience; Climate change globally perturbs water circulation thereby influencing ecosystems including cultivated land. Both harmful and beneficial species of insects are likely to be vulnerable to such changes in climate. As small animals with a disadvantageous surface area to body mass ratio, they face a risk of desiccation. A number of behavioural, physiological and genetic strategies are deployed to solve these problems during adaptation in various Drosophila species. Over 100 desiccation-related genes have been identified in laboratory and wild populations of the cosmopolitan fruit fly Drosophila melanogaster and its sister species in large-scale and single-gene approaches…
Species interactions, environmental gradients and body size shape population niche width
2021
1. Competition for shared resources is commonly assumed to restrict population-level niche width of coexisting species. However, the identity and abundance of coexisting species, the prevailing environmental conditions, and the individual body size may shape the effects of interspecific interactions on species’ niche width. 2. Here we study the effects of interspecific and intraspecific interactions, lake area and altitude, and fish body size on the trophic niche width and resource use of a generalist predator, the littoral-dwelling large, sparsely rakered morph of European whitefish (Coregonus lavaretus; hereafter LSR whitefish). We use stable isotope, diet and survey fishing data from 14 …
Spanish population trends in Internet searches for information on different diets
2019
Abstract Objective To use Google Trends to explore the trends of interest of the Spanish population regarding information related to different types of diets, focused on those that are popular and with evidence-based studies, over the last 10 years. Material and methods The search trends referred to the terms “Mediterranean diet”, “ketogenic diet”, “low fat diet”, “intermittent fasting” and “vegan diet” were analyzed. The relative search volumes (RSV) of the terms were compared. The direction of the trend was studied using the Spearman's correlation coefficient (SC). Results “Mediterranean diet” was the most widely searched term, with a median RSV of 16 (interquartile range [IQR] 6; range 8…
The Evidence Base for an Ideal Care Pathway for Frail Multimorbid Elderly : Combined Scoping and Systematic Intervention Review
2019
Source at https://doi.org/10.2196/12517. Background: There is a call for bold and innovative action to transform the current care systems to meet the needs of an increasing population of frail multimorbid elderly. International health organizations propose complex transformations toward digitally supported (1) Person-centered, (2) Integrated, and (3) Proactive care (Digi-PIP care). However, uncertainty regarding both the design and effects of such care transformations remain. Previous reviews have found favorable but unstable impacts of each key element, but the maturity and synergies of the combination of elements are unexplored. Objective: This study aimed to describe how the literature o…
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, …
Assessing Urban System Vulnerabilities to Flooding to Improve Resilience and Adaptation in Spatial Planning
2018
Fluvial, pluvial and coastal flooding are the most frequent and costly natural hazard. Cities are social hubs and life in cities is reliant on a number of services and functions such as housing, healthcare, education and other key daily facilities. Urban flooding can cause significant disruption to these services and wider impacts on the population. These impacts may be short or long with a variably spatial scale: urban systems are spatially distributed and the nature of this can have significant effects on flood impacts. From an urban-planning perspective, measuring this disruption and its consequences is fundamental in order to develop more resilient cities. Whereas the assessment of phys…
Improvement of lateral connectivity in a sector of River Hârtibaciu (Olt/Danube Basin)
2017
Abstract The Hârtibaciu River in the Alţâna area has a disturbed lateral connectivity owing to its lateral embankments, as a result of which fish communities in this river sector are negatively influenced. The method of obtaining the water supply for a new proposed wetland is by gravitation, and any excessive water supply to the wetland will be controled and directed to the Hârtibaciu River in a natural manner. A state-of-the-art man-made wetland should increase the quality of the habitat for local fish communities, especially for the Rhodeus sericeus population, which is a species of conservation interest.
Bio-inspired evolutionary dynamics on complex networks under uncertain cross-inhibitory signals
2019
Given a large population of agents, each agent has three possiblechoices between option 1 or 2 or no option. The two options are equally favorable and the population has to reach consensus on one of the two options quickly and in a distributed way. The more popular an option is, the more likely it is to be chosen by uncommitted agents. Agents committed to one option can be attracted by those committed to the other option through a cross-inhibitory signal. This model originates in the context of honeybee swarms, and we generalize it to duopolistic competition and opinion dynamics. The contributions of this work include (i) the formulation of a model to explain the behavioral traits of the ho…