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"Character transition"
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PLUMAGE AND MITOCHONDRIAL DNA HAPLOTYPE VARIATION ACROSS A MOVING HYBRID ZONE
by
Wood, Christopher
,
Rohwer, Sievert
,
Bermingham, Eldredge
in
Character transition
,
cytonuclear linkage
,
Dendroica occidentalis
2001
We analyze variation in phenotypes and mitochondrial DNA (mtDNA) haplotypes over the breeding ranges of hermit and Townsend's warblers and across two of their three hybrid zones. Within these two hybrid zones, we demonstrate that the placement, shape, and width of transitions in seven plumage characters are remarkably similar, suggesting that a balance between dispersal and sexual selection keeps these hybrid zones narrow. A consistent asymmetry in these character transition curves suggests that Townsend's warblers have a selective advantage over hermit warblers, which is presumably due to the aggressive superiority of Townsend's over hermit males (Pearson and Rohwer 2000). An association between plumage and mtDNA haplotypes shows that pure Townsend's warblers, but not pure hermit warblers, immigrate into these hybrid zones, further supporting the competitive superiority of Townsend's warblers over hermit warblers. The mitochondrial haplotype transitions across these hybrid zones are much wider than the phenotypic transitions and provide no indication that the mtDNA haplotypes representing these two warblers are selectively maintained. More importantly, the phenotypically pure populations of Townsend's warblers throughout a 2000‐km coastal strip north of the Washington hybrid zones contain a preponderance of hermit warbler mtDNA haplotypes. This result suggests massive movement of the hybrid zone between these warblers during the 5000 years since their most recent interglacial contact. We develop a model to explain the phenotypic and genetic divergence between these warblers and the evolution of their dramatic differences in aggressiveness; we also show how differences in male aggression, in combination with biased pairing patterns, can explain the haplotype footprint recording the historical movement of this hybrid zone.
Journal Article
CharMark: character-level Markov modeling for interpretable linguistic biomarkers of cognitive decline
2025
Dementia, one of the most prevalent neurodegenerative diseases, affects millions worldwide. Understanding linguistic markers of dementia is crucial for elucidating how cognitive decline manifests in speech patterns. Current non-invasive assessments like the Montreal Cognitive Assessment (MoCA) and Saint Louis University Mental Status (SLUMS) tests rely on manual interpretation and often lack detailed linguistic insight. This paper introduces a first-of-its-kind interpretable artificial intelligence (IAI) framework, CharMark , which leverages first-order Markov Chain models to characterize language production at the character level. By computing steady-state probabilities of character transitions in speech transcripts from individuals with dementia and healthy controls, we uncover distinctive character-usage patterns. The space character “ ”, representing pauses, (treated here as the space token between words rather than acoustic pauses), and letters such as “n” and “i” showed statistically significant differences between groups. Principal Component Analysis (PCA) revealed natural clustering aligned with cognitive status, while Kolmogorov-Smirnov tests confirmed distributional shifts. A Lasso Logistic Regression model further demonstrated that these character-level features possess strong discriminative potential. Our primary contribution is the identification and characterization of candidate linguistic biomarkers of cognitive decline; features that are both interpretable and easily computable. These findings highlight the potential of character-level modeling as a lightweight, scalable strategy for early-stage dementia screening, particularly in settings where more complex or audio-dependent models may be impractical.
Journal Article
Unusual heterostyly: style dimorphism and self-incompatibility are not tightly associated in Lithodora and Glandora (Boraginaceae)
2012
• Background and Aims Heterostyly is a floral polymorphism characterized by the reciprocal position of stamens and stigmas in different flower morphs in a population. This reciprocal herkogamy is usually associated with an incompatibility system that prevents selfing and intra-morph fertilization, termed a heteromorphic incompatibility system. In different evolutionary models explaining heterostyly, it has been alternately argued that heteromorphic incompatibility either preceded or followed the evolution of reciprocal herkogamy. In some models, reciprocal herkogamy and incompatibility have been hypothesized to be linked together during the evolution of the heterostylous system. • Methods We examine the incompatibility systems in species with different stylar polymorphisms from the genera Lithodora and Glandora (Boraginaceae). We then test whether evolution towards reciprocal herkogamy is associated with the acquisition of incompatibility. To this end, a phylogeny of these genera and related species is reconstructed and the morphological and reproductive changes that occurred during the course of evolution are assessed. • Key Results Both self-compatibility and self-incompatibility are found within the studied genera, along with different degrees of intra-morph compatibility. We report for the first time extensive variability among members of the genus Glandora and related species in terms of the presence or absence of intraspecies polymorphism and heteromorphic incompatibility. Overall, our results do not support a tight link between floral polymorphism and incompatibility systems. • Conclusions The independent evolution of stylar polymorphism and incompatibility appears to have occurred in this group of plants. This refutes the canonical view that there is strong linkage between these reproductive traits.
Journal Article
PLUMAGE AND MITOCHONDRIAL DNA HAPLOTYPE VARIATION ACROSS A MOVING HYBRID ZONE
2001
We analyze variation in phenotypes and mitochondrial DNA (mtDNA) haplotypes over the breeding ranges of hermit and Townsend's warblers and across two of their three hybrid zones. Within these two hybrid zones, we demonstrate that the placement, shape, and width of transitions in seven plumage characters are remarkably similar, suggesting that a balance between dispersal and sexual selection keeps these hybrid zones narrow. A consistent asymmetry in these character transition curves suggests that Townsend's warblers have a selective advantage over hermit warblers, which is presumably due to the aggressive superiority of Townsend's over hermit males (Pearson and Rohwer 2000). An association between plumage and mtDNA haplotypes shows that pure Townsend's warblers, but not pure hermit warblers, immigrate into these hybrid zones, further supporting the competitive superiority of Townsend's warblers over hermit warblers. The mitochondrial haplotype transitions across these hybrid zones are much wider than the phenotypic transitions and provide no indication that the mtDNA haplotypes representing these two warblers are selectively maintained. More importantly, the phenotypically pure populations of Townsend's warblers throughout a 2000-km coastal strip north of the Washington hybrid zones contain a preponderance of hermit warbler mtDNA haplotypes. This result suggests massive movement of the hybrid zone between these warblers during the 5000 years since their most recent interglacial contact. We develop a model to explain the phenotypic and genetic divergence between these warblers and the evolution of their dramatic differences in aggressiveness; we also show how differences in male aggression, in combination with biased pairing patterns, can explain the haplotype footprint recording the historical movement of this hybrid zone.
Journal Article
A Phylogenetic Analysis of Body Size Evolution and Biogeography in Chuckwallas (Sauromalus) and Other Iguanines
1997
The evolution of body size was reconstructed in chuckwallas (genus Sauromalus), large herbivorous lizards of southwest North America, using a phylogeny derived from sequence variation in the mitochondrial cytochrome b gene. The body mass of two endemic island species (S. hispidus and S. varius) is typically fivefold larger than mainland species. We tested the hypothesis that large body size has evolved on these islands in response to local ecological conditions against the alternative hypothesis that large size is simply retained from large iguanine ancestors. The most parsimonious tree topology depicts the insular gigantic Sauromalus as monophyletic, having diverged from a common ancestor on the Baja California peninsula after the radiation of smaller bodied clades. In a robustness analysis of this topology, we found general support for this tree over alternative topologies representing minimum evolution hypotheses that imply large body size is retained from large iguanine ancestors. The most parsimonious reconstruction of body size evolution implies a change from large to small size after the Sauromalus ancestor diverged from Iguana, and one reversal back to large size within Sauromalus. The large size increase in the gigantic clade contrasts with evolutionary stasis of small body size (for an iguanine) in mainland populations. The gigantic species show 3-4% total sequence divergence from S. obesus populations on the nearby Baja California peninsula, and mainland populations of S. obesus obesus show similar levels of divergence from each other. An analysis of character transitions and comparative behavior implicates predation, and its relaxation on isolated islands, as a strong selective force in Sauromalus. Patterns of genetic differentiation in Sauromalus and biogeographic implications are discussed.
Journal Article
Determining the transformative potential of circular agriculture initiatives
by
Silvius, Jelle
,
Termeer, Catrien J. A. M
,
de Boer, Imke J. M
in
Agriculture
,
Consumption
,
Food
2023
Policymakers and scientists regard emerging circular initiatives as levers for transformations towards more sustainable food systems. However, it remains unclear how to determine the extent to which circular initiatives have transformative potential. That is, can these initiatives foster a transformation as a result of how they currently bring circularity into practice? In the transformation literature, the characteristics of transformative initiatives are conceptualised in a generic and abstract way. To address this gap, we develop a heuristic of five characteristics for potentially transformative circular agriculture initiatives, which we illustrate with examples of existing initiatives. The heuristic builds on the ‘small wins’ and circular agriculture literature. Initiatives that hold transformative potential contribute to circular agriculture principles with outcomes that are concrete, in-depth and both technological and social in nature. Additionally, these initiatives faced barriers and overcame them. The heuristic enables policymakers, who call for circular solutions, to identify truly transformative circular initiatives.
Journal Article
Artificial Multisensory Neurons with Fused Haptic and Temperature Perception for Multimodal In‐Sensor Computing
2022
The human receives and transmits various information from the outside world through different sensory systems. The sensory neurons integrate various sensory inputs into a synthetical perception to monitor complex environments, and this fundamentally determines the way how we perceive the world. Developing multifunctional artificial sensory elements that can integrate multisensory perception plays a vital role in future intelligent perception systems, whereas prior spiking neurons reported can only handle single‐mode physical signals. Herein, a bioinspired haptic‐temperature fusion spiking neuron based upon a serial connection of piezoresistive sensor and VO2 volatile memristor is presented. The artificial sensory neuron is capable of detecting and encoding pressure and temperature inputs based on the voltage dividing effect and the intrinsic thermal sensitivity of metal–insulator transition in VO2. Recognition of Braille characters is achieved through multiple piezoresistive sensors, taking advantage of the spatial integration capabilities of such spiking neurons. Notably, the traditionally separate haptic and temperature signals can be fused physically in the sensory neuron when synchronizing the two sensory cues, which is able to recognize multimodal haptic/temperature patterns. The artificial multisensory neuron thus provides a promising approach toward e‐skin, neurorobotics, and human–machine interaction technologies. A preprint version of the article can be found at: https://www.authorea.com/doi/full/10.22541/au.164668806.60849882. Herein, a bioinspired haptic‐temperature fusion spiking neuron based on a combination of piezoresistive sensor and VO2 volatile memristor is demonstrated. The thermal characteristics of VO2 memristor and mechanical sensory properties of the piezoresistive sensor are exploited and combined in the same component, enabling multimodal in‐sensor computing. This can provide a promising approach toward e‐skin, neurorobotics, and human–machine interaction technologies.
Journal Article
Measurement of the mobility edge for 3D Anderson localization
2015
Anderson localization is a universal phenomenon affecting non-interacting quantum particles in a disordered environment. In three spatial dimensions, theory predicts a quantum phase transition from localization to diffusion at a critical energy, the mobility edge, which depends on the disorder strength. Although it has been recognized already long ago as a prominent feature of disordered systems, a complete experimental characterization of the mobility edge is still missing. Here we report the measurement of the mobility edge for ultracold atoms in a disordered potential created by laser speckles. We are able to control both the disorder strength and the energy of the system, so as to probe the position of the localization threshold in the disorder–energy plane. Our results might allow a direct experiment–theory comparison, which is a prerequisite to study the even more challenging problem of disorder and interactions.
The mobility edge characterizes the transition from localization to diffusion. This key parameter in Anderson localization was measured for a system of ultracold atoms in a tunable disordered potential created by laser speckles.
Journal Article
Character strengths, moral motivation and vocational identity in adolescents and young adults: a scoping review
by
De la Fuente, Jesús
,
Villacís, Jorge L.
,
Naval, Concepción
in
Behavioral Science and Psychology
,
Character
,
Ethical aspects
2023
Past reviews have examined the association between positive personality traits known as character strengths and work-related outcomes. However, little is known about the role of positive traits in the pre-career stage. This study aims to fill this gap by mapping the peer-reviewed literature on the relationships between character strengths, moral motivation and vocational identity in adolescents and young adult students. Scopus and Web of Science databases were used to identify English written sources published between 1980 and October 2020. Documents had to include one of the 24 positive psychology character strengths or a moral motivation construct (moral reasoning, moral identity or moral emotions) and one vocational identity process (commitment, exploration or reconsideration). 136 documents were selected (123 quantitative, 8 qualitative, and 5 theoretical). 15 strengths were studied together with a vocational identity process. The most investigated strengths were prudence (27.9%) curiosity (20.6%), hope (20.6%) and love (19.9%). Only one moral motivation construct (the moral emotion of empathy) was associated with vocational commitment. Four character strengths were the most studied in association with vocational identity. These strengths coincided with some skills and competencies promoted in career counselling. Some suggestions for future research on vocational development and character education are stated.
Journal Article
Understanding unequal ageing: towards a synthesis of intersectionality and life course analyses
2021
Intersectionality has received an increasing amount of attention in health inequalities research in recent years. It suggests that treating social characteristics separately—mainly age, gender, ethnicity, and socio-economic position—does not match the reality that people simultaneously embody multiple characteristics and are therefore potentially subject to multiple forms of discrimination. Yet the intersectionality literature has paid very little attention to the nature of ageing or the life course, and gerontology has rarely incorporated insights from intersectionality. In this paper, we aim to illustrate how intersectionality might be synthesised with a life course perspective to deliver novel insights into unequal ageing, especially with respect to health. First we provide an overview of how intersectionality can be used in research on inequality, focusing on intersectional subgroups, discrimination, categorisation, and individual heterogeneity. We cover two key approaches—the use of interaction terms in conventional models and multilevel models which are particularly focussed on granular subgroup differences. In advancing a conceptual dialogue with the life course perspective, we discuss the concepts of roles, life stages, transitions, age/cohort, cumulative disadvantage/advantage, and trajectories. We conclude that the synergies between intersectionality and the life course hold exciting opportunities to bring new insights to unequal ageing and its attendant health inequalities.
Journal Article