scholarly journals Development of a site fidelity index based on population capture-recapture data

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4782 ◽  
Author(s):  
Ayelen Tschopp ◽  
Mariano A. Ferrari ◽  
Enrique A. Crespo ◽  
Mariano A. Coscarella

BackgroundSite fidelity is considered as an animal’s tendency to return to a previously occupied place; this is a component of animal behaviour that allows us to understand movement patterns and aspects related to the animal’s life history. Although there are many site fidelity metrics, the lack of standardisation presents a considerable challenge in terms of comparability among studies.MethodsThis investigation focused on the theoretical development of a standardised composite site fidelity index and its statistical distribution in order to obtain reliable population-level site fidelity comparisons. The arithmetic and harmonic means were used as mathematical structures in order to create different indexes by combining the most commonly used indicators for site fidelity such as Occurrence, Permanence and Periodicity. The index performance was then evaluated in simulated populations and one real population of Commerson’s dolphins (Cephalorhynchus commersonii(Lacépède 1804)). In the first case, the indexes were evaluated based on how they were affected by different probability values such as the occurrence of the individual within the study area (φ) and capture probability (p). As a precision measure for the comparison of the indexes, the Wald confidence interval (CI) and the mean square error were applied. Given that there was no previous data concerning the distribution parameters of this population, bootstrap CIs were applied for the study case.ResultsEight alternative indexes were developed. The indexes with an arithmetic mean structure, in general, had a consistently inferior performance than those with a harmonic mean structure. The index IH4, in particular, achieved the best results in all of the scenarios and in the study case. Additionally, this index presented a normal distribution. As such, it was proposed as a standardised measure for site fidelity (Standardised Site Fidelity Index—SSFI).DiscussionThe SSFI is the first standardised metric that quantifies site fidelity at a populational level. It is an estimator that varies between zero and one and works in situations where detection is not perfect and effort can be constant or not. Moreover, it has an associated CI that allows users to make comparisons.

2003 ◽  
Vol 8 (5) ◽  
pp. 4-12
Author(s):  
Lorne Direnfeld ◽  
James Talmage ◽  
Christopher Brigham

Abstract This article was prompted by the submission of two challenging cases that exemplify the decision processes involved in using the AMA Guides to the Evaluation of Permanent Impairment (AMA Guides). In both cases, the physical examinations were normal with no evidence of illness behavior, but, based on their histories and clinical presentations, the patients reported credible symptoms attributable to specific significant injuries. The dilemma for evaluators was whether to adhere to the AMA Guides, as written, or to attempt to rate impairment in these rare cases. In the first case, the evaluating neurologist used alternative approaches to define impairment based on the presence of thoracic outlet syndrome and upper extremity pain, as if there were a nerve injury. An orthopedic surgeon who evaluated the case did not base impairment on pain and used the upper extremity chapters in the AMA Guides. The impairment ratings determined using either the nervous system or upper extremity chapters of the AMA Guides resulted in almost the same rating (9% vs 8% upper extremity impairment), and either value converted to 5% whole person permanent impairment. In the second case, the neurologist evaluated the individual for neuropathic pain (9% WPI), and the orthopedic surgeon rated the patient as Diagnosis-related estimates Cervical Category II for nonverifiable radicular pain (5% to 8% WPI).


Ecography ◽  
2021 ◽  
Author(s):  
Philippine Chambault ◽  
Tarek Hattab ◽  
Pascal Mouquet ◽  
Touria Bajjouk ◽  
Claire Jean ◽  
...  

2013 ◽  
Vol 59 (4) ◽  
pp. 485-505 ◽  
Author(s):  
Jon E. Brommer

Abstract Individual-based studies allow quantification of phenotypic plasticity in behavioural, life-history and other labile traits. The study of phenotypic plasticity in the wild can shed new light on the ultimate objectives (1) whether plasticity itself can evolve or is constrained by its genetic architecture, and (2) whether plasticity is associated to other traits, including fitness (selection). I describe the main statistical approach for how repeated records of individuals and a description of the environment (E) allow quantification of variation in plasticity across individuals (IxE) and genotypes (GxE) in wild populations. Based on a literature review of life-history and behavioural studies on plasticity in the wild, I discuss the present state of the two objectives listed above. Few studies have quantified GxE of labile traits in wild populations, and it is likely that power to detect statistically significant GxE is lacking. Apart from the issue of whether it is heritable, plasticity tends to correlate with average trait expression (not fully supported by the few genetic estimates available) and may thus be evolutionary constrained in this way. Individual-specific estimates of plasticity tend to be related to other traits of the individual (including fitness), but these analyses may be anti-conservative because they predominantly concern stats-on-stats. Despite the increased interest in plasticity in wild populations, the putative lack of power to detect GxE in such populations hinders achieving general insights. I discuss possible steps to invigorate the field by moving away from simply testing for presence of GxE to analyses that ‘scale up’ to population level processes and by the development of new behavioural theory to identify quantitative genetic parameters which can be estimated.


2017 ◽  
Vol 26 (6) ◽  
pp. 579-583 ◽  
Author(s):  
T. D. Cosco ◽  
K. Howse ◽  
C. Brayne

The extension of life does not appear to be slowing, representing a great achievement for mankind as well as a challenge for ageing populations. As we move towards an increasingly older population we will need to find novel ways for individuals to make the best of the challenges they face, as the likelihood of encountering some form of adversity increases with age. Resilience theories share a common idea that individuals who manage to navigate adversity and maintain high levels of functioning demonstrate resilience. Traditional models of healthy ageing suggest that having a high level of functioning across a number of domains is a requirement. The addition of adversity to the healthy ageing model via resilience makes this concept much more accessible and more amenable to the ageing population. Through asset-based approaches, such as the invoking of individual, social and environmental resources, it is hoped that greater resilience can be fostered at a population level. Interventions aimed at fostering greater resilience may take many forms; however, there is great potential to increase social and environmental resources through public policy interventions. The wellbeing of the individual must be the focus of these efforts; quality of life is an integral component to the enjoyment of additional years and should not be overlooked. Therefore, it will become increasingly important to use resilience as a public health concept and to intervene through policy to foster greater resilience by increasing resources available to older people. Fostering wellbeing in the face of increasing adversity has significant implications for ageing individuals and society as a whole.


2017 ◽  
Vol 4 (8) ◽  
pp. 170344 ◽  
Author(s):  
Thiago Mosqueiro ◽  
Chelsea Cook ◽  
Ramon Huerta ◽  
Jürgen Gadau ◽  
Brian Smith ◽  
...  

Variation in behaviour among group members often impacts collective outcomes. Individuals may vary both in the task that they perform and in the persistence with which they perform each task. Although both the distribution of individuals among tasks and differences among individuals in behavioural persistence can each impact collective behaviour, we do not know if and how they jointly affect collective outcomes. Here, we use a detailed computational model to examine the joint impact of colony-level distribution among tasks and behavioural persistence of individuals, specifically their fidelity to particular resource sites, on the collective trade-off between exploring for new resources and exploiting familiar ones. We developed an agent-based model of foraging honeybees, parametrized by data from five colonies, in which we simulated scouts, who search the environment for new resources, and individuals who are recruited by the scouts to the newly found resources, i.e. recruits. We varied the persistence of returning to a particular food source of both scouts and recruits and found that, for each value of persistence, there is a different optimal ratio of scouts to recruits that maximizes resource collection by the colony. Furthermore, changes to the persistence of scouts induced opposite effects from changes to the persistence of recruits on the collective foraging of the colony. The proportion of scouts that resulted in the most resources collected by the colony decreased as the persistence of recruits increased. However, this optimal proportion of scouts increased as the persistence of scouts increased. Thus, behavioural persistence and task participation can interact to impact a colony's collective behaviour in orthogonal directions. Our work provides new insights and generates new hypotheses into how variations in behaviour at both the individual and colony levels jointly impact the trade-off between exploring for new resources and exploiting familiar ones.


2017 ◽  
Author(s):  
Alex Mesoudi

AbstractHow do migration and acculturation (i.e. psychological or behavioral change resulting from migration) affect within- and between-group cultural variation? Here I answer this question by drawing analogies between genetic and cultural evolution. Population genetic models show that migration rapidly breaks down between-group genetic structure. In cultural evolution, however, migrants or their descendants can acculturate to local behaviors via social learning processes such as conformity, potentially preventing migration from eliminating between-group cultural variation. An analysis of the empirical literature on migration suggests that acculturation is common, with second and subsequent migrant generations shifting, sometimes substantially, towards the cultural values of the adopted society. Yet there is little understanding of the individual-level dynamics that underlie these population-level shifts. To explore this formally, I present models quantifying the effect of migration and acculturation on between-group cultural variation, for both neutral and costly cooperative traits. In the models, between-group cultural variation, measured using F statistics, is eliminated by migration and maintained by conformist acculturation. The extent of acculturation is determined by the strength of conformist bias and the number of demonstrators from whom individuals learn. Acculturation is countered by assortation, the tendency for individuals to preferentially interact with culturally-similar others. Unlike neutral traits, cooperative traits can additionally be maintained by payoff-biased social learning, but only in the presence of strong sanctioning institutions. Overall, the models show that surprisingly little conformist acculturation is required to maintain realistic amounts of between-group cultural diversity. While these models provide insight into the potential dynamics of acculturation and migration in cultural evolution, they also highlight the need for more empirical research into the individual-level learning biases that underlie migrant acculturation.


2021 ◽  
Author(s):  
Shinya Ito ◽  
Yufei Si ◽  
Alan M. Litke ◽  
David A. Feldheim

AbstractSensory information from different modalities is processed in parallel, and then integrated in associative brain areas to improve object identification and the interpretation of sensory experiences. The Superior Colliculus (SC) is a midbrain structure that plays a critical role in integrating visual, auditory, and somatosensory input to assess saliency and promote action. Although the response properties of the individual SC neurons to visuoauditory stimuli have been characterized, little is known about the spatial and temporal dynamics of the integration at the population level. Here we recorded the response properties of SC neurons to spatially restricted visual and auditory stimuli using large-scale electrophysiology. We then created a general, population-level model that explains the spatial, temporal, and intensity requirements of stimuli needed for sensory integration. We found that the mouse SC contains topographically organized visual and auditory neurons that exhibit nonlinear multisensory integration. We show that nonlinear integration depends on properties of auditory but not visual stimuli. We also find that a heuristically derived nonlinear modulation function reveals conditions required for sensory integration that are consistent with previously proposed models of sensory integration such as spatial matching and the principle of inverse effectiveness.


2018 ◽  
Author(s):  
William D. Chronister ◽  
Margaret B. Wierman ◽  
Ian E. Burbulis ◽  
Matthew J. Wolpert ◽  
Mark F. Haakenson ◽  
...  

AbstractMegabase-scale somatic copy number variants (CNVs) alter allelic diversity in a subset of human neocortical neurons. Reported frequencies of CNV neurons range from ∼5% of neurons in some individuals to greater than 30% in other individuals. Genome-wide and familial studies implicitly assume a constant brain genome when assessing the genetic risk architecture of neurological disease, thus it is critical to determine whether divergent reports of CNV neuron frequency reflect normal individual variation or technical differences between approaches. We generated a new dataset of over 800 human neurons from 5 neurotypical individuals and developed a computational approach that measures single cell library quality based on Bayesian Information Criterion and identifies integer-like variant segments from population-level statistics. A brain CNV atlas was assembled using our new dataset and published data from 10 additional neurotypical individuals. This atlas reveals that the frequency of neocortical CNV neurons varies widely among individuals, but that this variability is not readily accounted for by tissue quality or CNV detection approach. Rather, the age of the individual is anti-correlated with CNV neuron frequency. Fewer CNV neurons are observed in aged individuals than young individuals.


2012 ◽  
Vol 13 (4) ◽  
pp. 178 ◽  
Author(s):  
D Besada ◽  
G Van Cutsem ◽  
E Goemaere ◽  
N Ford ◽  
H Bygrave ◽  
...  

In a previous issue of the Southern African Journal of HIV Medicine, Pillay and Black summarised the trade-offs of the safety of efavirenz use in pregnancy (Pillay P, Black V. Safety, strength and simplicity of efavirenz in pregnancy. Southern African Journal of HIV Medicine 2012;13(1):28-33.). Highlighting the benefits of the World Health Organization’s proposed options for the prevention of mother-to-child transmission (PMTCT) of HIV, the authors argued that the South African government should adopt Option B as national PMTCT policy and pilot projects implementing Option B+ as a means of assessing the individual- and population-level effect of the intervention. We echo this call and further propose that the option to remain on lifelong antiretroviral therapy, effectively adopting PMTCT Option B+, be offered to pregnant women following the cessation of breastfeeding, for their own health, following the provision of counselling on associated benefits and risks. Here we highlight the benefits of Options B and B+.


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