Search results for "DEM"

Bachelor groups form due to individual choices or environmental disrupters in African striped mice

2021

International audience; In several mammal species, bachelor groups occur as a regular life history stage between dispersal and becoming the breeding male of a multi-female group. However, it is rarely investigated how such groups come into existence and how males that choose this strategy differ in life history traits from other males. Males of the socially flexible African striped mouse Rhabdomys pumilio have been historically reported to adopt one of three alternative tactics, i.e., small group-living philopatric males, intermediate solitary living roaming males, or large group-living territorial males. Here, we describe for the first time, bachelors as a fourth male tactic. Using long-te…

How partnerships end in guillemots Uria aalge : chance events, adaptive change, or forced divorce?

2007

Divorce in socially monogamous species can result from different mechanisms, for example, chance events, active desertion of the partner, or the intrusion of a third individual ousting the partner. We compared the predictions associated with such mechanisms with data from common guillemots (Uria aalge) breeding on the Isle of May, Scotland. The data cover the years 1982--2005 and show a yearly divorce rate of 10.2%. In most divorces (86%), one of the original partners moved to another breeding site, whereas the other bird stayed and bred with a new partner. On average, movers had a significantly lower breeding success after divorce, stayers were largely unaffected, whereas the incoming bird…

From habitat use to social behavior: natural history of a voiceless poison frog, Dendrobates tinctorius

2019

AbstractDescriptive studies of natural history have always been a source of knowledge on which experimental work and scientific progress rely. Poison frogs are a well-studied group of small Neotropical frogs with diverse parental behaviors, distinct calls, and bright colors that warn predators about their toxicity; and a showcase of advances in fundamental biology through natural history observations. The dyeing poison frog, Dendrobates tinctorius, is emblematic of the Guianas region, widespread in the pet-trade, and increasingly popular in research. This species shows several unusual behaviors, such as the lack of advertisement calls and the aggregation around tree-fall gaps, which remain …

Identification and biological traits of a planthopper from the genus Pentastiridius (Hemiptera: Cixiidae) adapted to an annual cropping rotation

2009

International audience; Cixiid planthoppers have been shown to vector phloem-limited prokaryotes associated with plant diseases world-wide. In eastern France, an emerging disease of sugar beet called syndrome basses richesses has been associated with phloem-restricted bacteria transmitted by a cixiid planthopper within the genus Pentastiridius. Early investigation suggested the species being Pentastiridius beieri. On the basis of a morphological and phylogenetic study we report the identification of the planthopper as Pentastiridius leporinus. Furthermore we report some biological traits of the species, which shows a surprising ecological adaptation to an annual cropping rotation sugar beet…

How to reach optimal estimates of confidence intervals in microscopic counting of phytoplankton?

2021

Abstract Present practices in the microscopic counting of phytoplankton to estimate the reliability of results rely on the assumption of a random distribution of taxa in sample preparations. In contrast to that and in agreement with the literature, we show that aggregated distribution is common and can lead to over-optimistic confidence intervals, if estimated according to the shortcut procedure of Lund et al. based on the number of counted cells. We found a good linear correlation between the distribution independent confidence intervals for medians and those for parametric statistics so that 95% confidence intervals can be approximated by using a correction factor of 1.4. Instead, the rec…

Polypore communities and their substrate characteristics in Atlantic forest fragments in southeast Brazil

2018

Anthropogenic environmental changes have resulted in biodiversity crisis. Although tropical rainforests are one of the global biodiversity hotspots, their biodiversity is still poorly known. Especially fungi are poorly represented in national Red Lists and conservation plans, despite their important role in ecosystem functioning. We studied wood-inhabiting fungi (polypores) in four areas within two Atlantic rainforest fragments in Southeast Brazil. Our aim was to investigate fungal substrate characteristics and community composition. Deadwood amount ranged from 27 to 82 m3/ha among the four study areas and altogether we recorded 53 polypore species. More species were observed in intermediat…

Out in the open : behavior’s effect on predation risk and thermoregulation by aposematic caterpillars

2020

Abstract Warning coloration should be under strong stabilizing selection but often displays considerable intraspecific variation. Opposing selection on color by predators and temperature is one potential explanation for this seeming paradox. Despite the importance of behavior for both predator avoidance and thermoregulation, its role in mediating selection by predators and temperature on warning coloration has received little attention. Wood tiger moth caterpillars, Arctia plantaginis, have aposematic coloration, an orange patch on the black body. The size of the orange patch varies considerably: individuals with larger patches are safer from predators, but having a small patch is beneficia…

2018

<b><i>Background:</i></b> A major and complex challenge when trying to support individuals with dementia is meeting the needs of those who experience changes in behaviour and mood. <b><i>Aim:</i></b> To explore how a sensor measuring electrodermal activity (EDA) impacts assistant nurses’ structured assessments of problematic behaviours amongst people with dementia and their choices of care interventions. <b><i>Methods:</i></b> Fourteen individuals with dementia wore a sensor that measured EDA. The information from the sensor was presented to assistant nurses during structured assessments of problematic behaviours. The e…

Selecting students for medical school: What predicts success during basic science studies? A cognitive approach

1996

This study focuses on differences between multiple-choice science tests and a learning-from-text (LFT) test, and how these tests predict success in basic medical studies. The subjects (N = 503) were applicants to the Helsinki University Medical Faculty. All of them had to take an entrance examination in order to be considered for admission to a 6-year study programme combining medical school and graduate studies. The entrance examination consisted of three traditional multiple-choice science tests and one LFT test, the latter designed to measure deep-level processing of text. A follow-up study was conducted in order to see how the different tasks were related to the grades and pace of study…

Energy Policies and Sustainable Management of Energy Sources

2017

Sustainability of current energy policies and known mid-term policies are analised in their multiple facets. First an overview is given about the trend of global energy demand and energy production, analysing the share of energy sources and the geographic distribution of demand, on the basis of statistics and projections published by major agencies. The issue of sustainability of the energy cycle is finally addressed, with specific reference to systems with high share of renewable energy and storage capability, highlighting some promising energy sources and storage approaches.