A complex speciation-richness relationship in a simple neutral model

Speciation is the "elephant in the room" of community ecology. As the ultimate source of biodiversity, its integration in ecology's theoretical corpus is necessary to understand community assembly. Yet, speciation is often completely ignored or stripped of its spatial dimension. Recent approaches based on network theory have allowed ecologists to effectively model complex landscapes. In this study, we use this framework to model allopatric and parapatric speciation in networks of communities and focus on the relationship between speciation, richness, and the spatial structure of communities. We find a strong opposition between speciation and local richness, with speciation being more common in isolated communities and local richness being higher in more connected communities. Unlike previous models, we also find a transition to a positive relationship between speciation and local richness when dispersal is low and the number of communities is small. Also, we use several measures of centrality to characterize the effect of network structure on diversity. The degree, the simplest measure of centrality, is found to be the best predictor of local richness and speciation, although it loses some of its predictive power as connectivity grows. Our framework shows how a simple neutral model can be combined with network theory to reveal complex relationships between speciation, richness, and the spatial organization of populations.Comment: 9 pages, 5 figures, 1 table, 50 reference

Correlates of Discordance between Perceived and Objective Distances to Local Fruit and Vegetable Retailers

Background: Perceptions of neighbourhood attributes such as proximity of food retailers that are discordant with objective measures of the same are associated with poor health behaviours and weight gain. Factors associated with discordant perceptions are likely relevant to planning more effective interventions to improve health. Purpose: Analysis of cross-sectional relationships between individual and neighbourhood factors and overestimations of walking distances to local fruit/vegetable retailers (FVR). Methods: Perceived walking times, converted to distances, between participant residences and FVR were compared with objectively-assessed road network distances calculated with a Geographic Information System for n = 1305 adults residing in Adelaide, South Australia. Differences between perceived and objective distances were expressed as ‘overestimated’ distances and were analysed relative to perceptions consistent with objective distances. Cross-sectional associations were evaluated between individual socio-demographic, health, and area-level characteristics and overestimated distances to FVR using multilevel logistic regression. Results: Agreement between objective and perceived distances between participants’ residence and the nearest FVR was only fair (weighted kappa = 0.22). Overestimated distances to FVR were positively associated with mental well-being, and were negatively associated with household income, physical functioning, sense of community, and objective distances to greengrocers. Conclusions: Individual characteristics and features of neighbourhoods were related to overestimated distances to FVR. Sense of connectivity and shared identity may shape more accurate understandings of local resource access, and offer a focal point for tailored public health initiatives that bring people together to achieve improved health behaviour

High expression of TROP2 characterizes different cell subpopulations in androgen-sensitive and androgenindependent prostate cancer cells

Progression of castration-resistant tumors is frequent in prostate cancer. Current systemic treatments for castration-resistant prostate cancer only produce modest increases in survival time and self-renewing Tumor-Initiating Cells (TICs) are suspected to play an important role in resistance to these treatments. However it remains unclear whether the same TICs display both chemo-resistance and self-renewing abilities throughout progression from early stage lesions to late, castration resistant tumors. Here, we found that treatment of mice bearing LNCaP-derived xenograft tumors with cytotoxic (docetaxel) and anti-androgen (flutamide) compounds enriched for cells that express TROP2, a putative TIC marker. Consistent with a tumor-initiating role, TROP2high cells from androgen-sensitive prostate cancer cell lines displayed an enhanced ability to re-grow in culture following treatment with taxane-based chemotherapy with or without androgen blockade. TROP2 down-regulation in these cells reduced their ability to recur after treatment with docetaxel, in the presence or absence of flutamide. Accordingly, in silico analysis of published clinical data revealed that prostate cancer patients with poor prognosis exhibit significantly elevated TROP2 expression level compared to low-risk patients, particularly in the case of patients diagnosed with early stage tumors. In contrast, in androgen-independent prostate cancer cell lines, TROP2high cells did not exhibit a differential treatment response but were characterized by their high self-renewal ability. Based on these findings we propose that high TROP2 expression identifies distinct cell sub-populations in androgen-sensitive and androgenindependent prostate tumors and that it may be a predictive biomarker for prostate cancer treatment response in androgen-sensitive tumors.Jinhan Xie, Christina Mølck, Sophie Paquet-Fifield, Lisa Butler, Erica Sloan, Sabatino Ventura, Frédéric Holland

Spin polarization and magneto-luminescence of confined electron-hole systems

A BCS-like variational wave-function, which is exact in the infinite field limit, is used to study the interplay among Zeeman energies, lateral confinement and particle correlations induced by the Coulomb interactions in strongly pumped neutral quantum dots. Band mixing effects are partially incorporated by means of field-dependent masses and g-factors. The spin polarization and the magneto-luminescence are computed as functions of the number of electron-hole pairs present in the dot and the applied magnetic field.Comment: To appear in Phys. Rev.

HOXA3 Modulates Injury-Induced Mobilization and Recruitment of Bone Marrow-Derived Cells

The regulated recruitment and differentiation of multipotent bone marrow-derived cells (BMDCs) to sites of injury are critical for efficient wound healing. Previously we demonstrated that sustained expression of HOXA3 both accelerated wound healing and promoted angiogenesis in diabetic mice. In this study, we have used green fluorescent protein-positive bone marrow chimeras to investigate the effect of HOXA3 expression on recruitment of BMDCs to wounds. We hypothesized that the enhanced neovascularization induced by HOXA3 is due to enhanced mobilization, recruitment, and/or differentiation of BMDCs. Here we show that diabetic mice treated with HOXA3 displayed a significant increase in both mobilization and recruitment of endothelial progenitor cells compared with control mice. Importantly, we also found that HOXA3-treated mice had significantly fewer inflammatory cells recruited to the wound compared with control mice. Microarray analyses of HOXA3-treated wounds revealed that indeed HOXA3 locally increased expression of genes that selectively promote stem/progenitor cell mobilization and recruitment while also suppressing expression of numerous members of the proinflammatory nuclear factor κB pathway, including myeloid differentiation primary response gene 88 and toll-interacting protein. Thus HOXA3 accelerates wound repair by mobilizing endothelial progenitor cells and attenuating the excessive inflammatory response of chronic wounds

Effets d’une thérapie intensive de groupe pour les adolescentes et adolescents franco-québécois qui bégaient : résultats d’une étude rétrospective = Impact of intensive group therapy for Québec-French-speaking adolescents who stutter: Findings of a retrospective study

Abrégé Le bégaiement développemental est un trouble complexe qui affecte non seulement la parole, mais également les relations sociales et le développement identitaire chez plusieurs adolescentes et adolescents qui bégaient. Les thérapies de groupe semblent une modalité appréciée et efficace auprès de cette population. L’Association des jeunes bègues du Québec propose depuis 1993 une thérapie intensive de groupe, sous forme de camp de vacances, aux jeunes de 13 à 17 ans. Au total, les adolescentes et adolescents reçoivent environ 50 heures d’intervention orthophonique, lesquelles sont consacrées depuis 2011 à une application adaptée du programme Camperdown accompagnée d’activités d’éducation psychologique inspirées de la thérapie cognitivocomportementale. L’objectif de la présente étude est d’évaluer les effets de cette thérapie intensive de groupe sur le plan de la parole. Pour y parvenir, une étude clinique rétrospective a été effectuée. Les données sociodémographiques et cliniques ont été extraites d’un échantillon de 44 dossiers de jeunes de 13 à 17 ans ayant bénéficié de la thérapie de groupe de l’Association des jeunes bègues du Québec de 2011 à 2019. Des statistiques descriptives ont permis d’obtenir un portrait détaillé des participantes et participants. Des analyses statistiques non paramétriques ont démontré une diminution significative (p < 0,01) des valeurs de pourcentage de syllabes bégayées et de sévérité subjective du bégaiement au terme des six jours de thérapie intensive. De plus, la majorité des jeunes avaient amorcé la phase III du programme Camperdown — qui comporte quatre phases au total. D’autres recherches sont nécessaires afin d’étudier l’efficacité de l’intervention auprès des adolescentes et adolescents qui bégaient, notamment en regard des facteurs psychosociaux associés au bégaiement. Abstract Developmental stuttering is a complex disorder that affects not only speech, but also social interactions and identity formation in many adolescents who stutter. Group therapy appears to be a popular and effective treatment modality for working with this population. Since 1993, the Association des jeunes bègues du Québec [Québec Association of Young Stutterers] has been offering intensive group therapy during summer camps to young people aged 13 to 17 years. In total, the adolescents receive approximately 50 hours of speech-language pathology therapy, which has been devoted to an adapted form of the Camperdown Program with cognitive behaviour therapy inspired activities since 2011. The aim of this study was to evaluate the impact of this intensive group therapy on adolescents’ speech abilities using a retrospective clinical study design. Sociodemographic and clinical data were drawn from the clinical files of 44 individuals aged 13 to 17 who took part in the group therapy offered by the Association des jeunes bègues du Québec between 2011 and 2019. Descriptive statistics provided a detailed profile of the participants. Nonparametric statistical analyses showed a significant decrease (p < .01) in the percentage of syllables stuttered and in the subjective severity of stuttering after 6 days of intensive therapy. In addition, most of the individuals had begun Stage III of the four-stage Camperdown Program. Further research is needed to investigate the effectiveness of this intervention with adolescents who stutter, particularly with regard to the psychosocial factors associated with stuttering. © 2023, Canadian Association of Speech-Language Pathologists and Audiologists. All rights reserved