On distinguishing trees by their chromatic symmetric functions

Let $T$ be an unrooted tree. The \emph{chromatic symmetric function} $X_T$, introduced by Stanley, is a sum of monomial symmetric functions corresponding to proper colorings of $T$. The \emph{subtree polynomial} $S_T$, first considered under a different name by Chaudhary and Gordon, is the bivariate generating function for subtrees of $T$ by their numbers of edges and leaves. We prove that $S_T =$, where $$ is the Hall inner product on symmetric functions and $\Phi$ is a certain symmetric function that does not depend on $T$. Thus the chromatic symmetric function is a stronger isomorphism invariant than the subtree polynomial. As a corollary, the path and degree sequences of a tree can be obtained from its chromatic symmetric function. As another application, we exhibit two infinite families of trees (\emph{spiders} and some \emph{caterpillars}), and one family of unicyclic graphs (\emph{squids}) whose members are determined completely by their chromatic symmetric functions.Comment: 16 pages, 3 figures. Added references [2], [13], and [15

On distinguishing trees by their chromatic symmetric functions

This is the author's accepted manuscript

Nurse Educators\u27 Perceptions of Ecoliteracy in Undergraduate Nursing Education

Introduction: Increased human health concerns related to the natural environment and climate change are having a growing impact on nursing practice. This past year in Canada, for example, British Columbia reported the highest number of heat related deaths, followed by devasting forest fires in many provinces that have disproportionately impacted Indigenous Peoples. Nurses are well positioned to address the direct health impacts associated with climate change. As a result, nurses require an increased level of ecoliteracy to address the health impacts linked to climate change. The role of the nurse in addressing the health impacts of climate change are vast, ranging from direct patient care, education and advocacy, their role includes supporting individuals, communities, and populations to mitigate, adapt and build resiliency in the face of a changing climate. Background: Regulatory and professional associations support the professional emphasis on the significance of ecoliteracy yet there is insufficient understanding of the resistance to the content in nursing curricula. Although current literature supports an increased emphasis on the integration of ecosystem health concerns and the impact on human health within undergraduate nursing education, there is a paucity of empirical evidence regarding nursing educators’ perspectives on the subject. This study is a first step in gaining a greater understanding of the perspectives of nurse educators on ecoliteracy within undergraduate nursing education programs in one Canadian province. Methods: This qualitative research study included 13 nurse educators from three diverse academic settings. Data were collected using semi-structured, open-ended interview questions, followed by content analysis of the data. Results: Data analysis revealed five key themes: 1) Importance of ecoliteracy in undergraduate nursing programs; 2) Current integration of ecoliteracy concepts in curricula; 3) Future considerations for ecoliteracy content; 4) Barriers to the inclusion of content supportive of ecoliteracy in curricula; 5) Strategies to address barriers. While educators feel that ecoliteracy is important in undergraduate nursing, they noted that the current integration of climate content in the curriculum is uneven. Barriers and potential strategies to integrating this content are identified. Conclusion: The findings of this study can be used for curriculum revision and to stimulate innovation and research in nursing education. This study creates the opportunity for a larger scale replication study, pilot studies of the integration of concepts that would support ecoliteracy, and further research on the topic. This study identified that many complexities are involved in achieving ecoliteracy in nursing education and suggest that while threading of content can address the urgent need, further research is required to identify entry to practice requirements for undergraduate nursing programs. Résumé Introduction : Les préoccupations grandissantes associées aux liens entre la santé humaine, l’environnement naturel et les changements climatiques touchent de plus en plus la pratique infirmière. Au cours de la dernière année au Canada, la Colombie-Britannique a signalé le plus grand nombre de décès liés à la chaleur, suivie par des incendies de forêt dévastateurs dans de nombreuses provinces qui ont affecté de manière disproportionnée les peuples autochtones. Les infirmières sont bien placées pour faire face aux impacts directs des changements climatiques sur la santé, et doivent donc avoir un niveau plus élevé d’écolittératie afin de composer avec les impacts des changements climatiques sur la santé. Le rôle de l’infirmière dans la lutte contre les impacts du changement climatique sur la santé est vaste, allant des soins directs aux patients, à la formation et à la défense des droits, et comprenant le soutien aux individus, aux communautés et aux populations pour atténuer, favoriser l’adaptation et renforcer la résilience par rapport au changement climatique. Contexte : Les associations réglementaires et professionnelles appuient l’accent mis par les professionnels sur l’importance de l’écolittératie, mais la compréhension de la résistance au contenu des programmes d’études en sciences infirmières est insuffisante. Bien que la littérature actuelle appuie l’importance accrue accordée à l’intégration des préoccupations liées à la santé des écosystèmes et à l’impact sur la santé humaine dans la formation en sciences infirmières au premier cycle, il existe peu de résultats empiriques concernant les perceptions des infirmières enseignantes sur le sujet. Cette étude représente une première étape pour mieux comprendre leurs perspectives sur l’écolittératie dans le cadre des programmes de formation en sciences infirmières au premier cycle dans une province canadienne. Méthode : Cette recherche qualitative incluait 13 infirmières enseignantes de 3 milieux universitaires différents. Les données ont été recueillies à l’aide de questions ouvertes lors d’entrevues semi-structurées, suivies d’une analyse de contenu. Résultats : L’analyse des données a dévoilé cinq thèmes clés : 1) L’importance de l’écolittératie dans les programmes en sciences infirmières de premier cycle; 2) Le niveau actuel d’intégration des notions d’écolittératie au sein des programmes d’études; 3) Les considérations pour l’ajout de contenu en matière d’écolittératie à l’avenir; 4) Les obstacles à l’inclusion de contenus favorables à l’écolittératie dans les programmes d’études; et, 5) Les stratégies pour franchir ces obstacles. Bien que les enseignantes estiment que l’écolittératie est importante en sciences infirmières au premier cycle, elles ont noté que l’intégration actuelle de contenu lié au climat dans les programmes d’études est inégale. Les obstacles et les stratégies potentielles à l’intégration de ce contenu sont identifiés. Conclusion : Les résultats de cette étude peuvent servir pour la révision des programmes et pour stimuler l’innovation et la recherche en formation en sciences infirmières. Cette étude crée l’occasion de refaire l’étude à plus grande échelle, de proposer des études pilotes sur l’intégration de concepts qui soutiendraient l’écolittératie et d’autres recherches sur le sujet. Cette étude a mis en évidence de nombreuses complexités qu’implique l’atteinte de l’écolittératie dans la formation en sciences infirmières et suggère que même si la mise en place du contenu peut répondre au besoin urgent, des recherches supplémentaires sont nécessaires pour déterminer les exigences d’entrée à la pratique au terme des programmes de sciences infirmières de premier cycle

Unmasking white delusion: a critical analysis for the organization

The article summarizes the arguments of the social debate regarding white delusion in the organization. This article delves into the phenomenon of white delusion, a term coined by the author, Stacey Morin, which signifies a lack of awareness and denial of systemic racial disparities in marginalized communities. The analysis focuses on Morin's and Bishop’s conceptualization of white delusion in the organization and the subsequent development of the Unmasking White Delusion: DEI model. This model, grounded in the framework of critical race theory, explores the denial, evaluation, and implementation phases, which aim to address and eliminate white delusion within organizations. The research contributes to the ongoing dialogue surrounding diversity and inclusion and addresses a gap in knowledge. The systematization of literary sources and approaches to solving the problem indicates that the white delusion is harmful to the organization. The urgency of addressing this problem stems from the absence of an inclusive and diverse culture, leading to diminished productivity and innovation. Our research methodology followed a logical sequence, beginning with a systematic literature review that critically analyzed the issue of white delusion within the organizational context. The objective was to unravel its complexities and comprehend how it impedes progress toward a more inclusive and equitable culture. The literature was critically analyzed based on concepts aligned with each phase of the Unmasking White Delusion: DEI model within the overarching framework of critical race theory. We contend that adopting the Unmasking White Delusion DEI model will play a pivotal role in mitigating the adverse effects of white delusion within the organization. The results from our thorough analysis of the literature review spurred the development of the Unmasking White Delusion: DEI model. This model serves as a visual guide and strategic tool for organizations seeking to eradicate white delusion and cultivate a culture of psychological safety for minority employees. By applying this model and integrating the Critical Race Theory framework, organizations can effectively confront white delusion through a comprehensive three-phase approach—denial, evaluation, and implementation. This entails organizations recognizing, assessing, and translating insights into actionable strategies, fostering a more inclusive and equitable workplace. The main conclusions of the research highlight the multifaceted process of eliminating white delusion in the organization

The relationship between parent and child dysfunctional beliefs about sleep and child sleep

Cognitive theories emphasise the role of dysfunctional beliefs about sleep in the development and maintenance of sleep-related problems (SRPs). The present research examines how parents' dysfunctional beliefs about children's sleep and child dysfunctional beliefs about sleep are related to each other and to children's subjective and objective sleep. Participants were 45 children aged 11 -12 years and their parents. Self-report measures of dysfunctional beliefs about sleep and child sleep were completed by children, mothers and fathers. Objective measures of child sleep were taken using actigraphy. The results showed that child dysfunctional beliefs about sleep were correlated with father (r=.43, p<.05) and mother (r=.43, p<.05) reported child SRPs, and with Sleep Onset Latency (r=.34, p<.05). Maternal dysfunctional beliefs about child sleep were related to child SRPs as reported by mothers (r=.44, p<.05), and to child dysfunctional beliefs about sleep (r=.37, p<.05). Some initial evidence was found for a mediation pathway in which child dyfunctional beliefs mediate the relationship between parent dysfunctional beliefs and child sleep. The results support the cognitive model of SRPs and contribute to the literature by providing the first evidence of familial aggregation of dysfunctional beliefs about sleep

Weakened magnetic braking as the origin of anomalously rapid rotation in old field stars

A knowledge of stellar ages is crucial for our understanding of many astrophysical phenomena, and yet ages can be difficult to determine. As they become older, stars lose mass and angular momentum, resulting in an observed slowdown in surface rotation. The technique of 'gyrochronology' uses the rotation period of a star to calculate its age. However, stars of known age must be used for calibration, and, until recently, the approach was untested for old stars (older than 1 gigayear, Gyr). Rotation periods are now known for stars in an open cluster of intermediate age (NGC 6819; 2.5 Gyr old), and for old field stars whose ages have been determined with asteroseismology. The data for the cluster agree with previous period-age relations, but these relations fail to describe the asteroseismic sample. Here we report stellar evolutionary modelling, and confirm the presence of unexpectedly rapid rotation in stars that are more evolved than the Sun. We demonstrate that models that incorporate dramatically weakened magnetic braking for old stars can---unlike existing models---reproduce both the asteroseismic and the cluster data. Our findings might suggest a fundamental change in the nature of ageing stellar dynamos, with the Sun being close to the critical transition to much weaker magnetized winds. This weakened braking limits the diagnostic power of gyrochronology for those stars that are more than halfway through their main-sequence lifetimes.Comment: 25 pages, 3 figures in main paper, 6 extended data figures, 1 table. Published in Nature, January 2016. Please see https://youtu.be/O6HzYgP5uyc for a video description of the resul

Bone Density, Microstructure and Strength in Obese and Normal Weight Men and Women in Younger and Older Adulthood

Obesity is associated with greater areal BMD (aBMD) and is considered protective against hip and vertebral fracture. Despite this, there is a higher prevalence of lower leg and proximal humerus fracture in obesity. We aimed to determine if there are site‐specific differences in BMD, bone structure, or bone strength between obese and normal‐weight adults. We studied 100 individually‐matched pairs of normal (body mass index [BMI] 18.5 to 24.9 kg/m2) and obese (BMI >30 kg/m2) men and women, aged 25 to 40 years or 55 to 75 years. We assessed aBMD at the whole body (WB), hip (TH), and lumbar spine (LS) with dual‐energy X‐ray absorptiometry (DXA), LS trabecular volumetric BMD (Tb.vBMD) by quantitative computed tomography (QCT), and vBMD and microarchitecture and strength at the distal radius and tibia with high‐resolution peripheral QCT (HR‐pQCT) and micro–finite element analysis. Serum type 1 procollagen N‐terminal peptide (P1NP) and collagen type 1 C‐telopeptide (CTX) were measured by automated electrochemiluminescent immunoassay (ECLIA). Obese adults had greater WB, LS, and TH aBMD than normal adults. The effect of obesity on LS and WB aBMD was greater in older than younger adults (p < 0.01). Obese adults had greater vBMD than normal adults at the tibia (p < 0.001 both ages) and radius (p < 0.001 older group), thicker cortices, higher cortical BMD and tissue mineral density, lower cortical porosity, higher trabecular BMD, and higher trabecular number than normal adults. There was no difference in bone size between obese and normal adults. Obese adults had greater estimated failure load at the radius (p < 0.05) and tibia (p < 0.01). Differences in HR‐pQCT measurements between obese and normal adults were seen more consistently in the older than the younger group. Bone turnover markers were lower in obese than in normal adults. Greater BMD in obesity is not an artifact of DXA measurement. Obese adults have higher BMD, thicker and denser cortices, and higher trabecular number than normal adults. Greater differences between obese and normal adults in the older group suggest that obesity may protect against age‐related bone loss and may increase peak bone mass

Circadian Integration of Glutamatergic Signals by Little SAAS in Novel Suprachiasmatic Circuits

Neuropeptides are critical integrative elements within the central circadian clock in the suprachiasmatic nucleus (SCN), where they mediate both cell-to-cell synchronization and phase adjustments that cause light entrainment. Forward peptidomics identified little SAAS, derived from the proSAAS prohormone, among novel SCN peptides, but its role in the SCN is poorly understood.Little SAAS localization and co-expression with established SCN neuropeptides were evaluated by immunohistochemistry using highly specific antisera and stereological analysis. Functional context was assessed relative to c-FOS induction in light-stimulated animals and on neuronal circadian rhythms in glutamate-stimulated brain slices. We found that little SAAS-expressing neurons comprise the third most abundant neuropeptidergic class (16.4%) with unusual functional circuit contexts. Little SAAS is localized within the densely retinorecipient central SCN of both rat and mouse, but not the retinohypothalamic tract (RHT). Some little SAAS colocalizes with vasoactive intestinal polypeptide (VIP) or gastrin-releasing peptide (GRP), known mediators of light signals, but not arginine vasopressin (AVP). Nearly 50% of little SAAS neurons express c-FOS in response to light exposure in early night. Blockade of signals that relay light information, via NMDA receptors or VIP- and GRP-cognate receptors, has no effect on phase delays of circadian rhythms induced by little SAAS.Little SAAS relays signals downstream of light/glutamatergic signaling from eye to SCN, and independent of VIP and GRP action. These findings suggest that little SAAS forms a third SCN neuropeptidergic system, processing light information and activating phase-shifts within novel circuits of the central circadian clock

Relationship between Activity in Human Primary Motor Cortex during Action Observation and the Mirror Neuron System

The attenuation of the beta cortical oscillations during action observation has been interpreted as evidence of a mirror neuron system (MNS) in humans. Here we investigated the modulation of beta cortical oscillations with the viewpoint of an observed action. We asked subjects to observe videos of an actor making a variety of arm movements. We show that when subjects were observing arm movements there was a significant modulation of beta oscillations overlying left and right sensorimotor cortices. This pattern of attenuation was driven by the side of the screen on which the observed movement occurred and not by the hand that was observed moving. These results are discussed in terms of the firing patterns of mirror neurons in F5 which have been reported to have similar properties

Fitness Cost of Resistance to Bt Cotton Linked with Increased Gossypol Content in Pink Bollworm Larvae

Fitness costs of resistance to Bacillus thuringiensis (Bt) crops occur in the absence of Bt toxins, when individuals with resistance alleles are less fit than individuals without resistance alleles. As costs of Bt resistance are common, refuges of non-Bt host plants can delay resistance not only by providing susceptible individuals to mate with resistant individuals, but also by selecting against resistance. Because costs typically vary across host plants, refuges with host plants that magnify costs or make them less recessive could enhance resistance management. Limited understanding of the physiological mechanisms causing fitness costs, however, hampers attempts to increase costs. In several major cotton pests including pink bollworm (Pectinophora gossypiella), resistance to Cry1Ac cotton is associated with mutations altering cadherin proteins that bind this toxin in susceptible larvae. Here we report that the concentration of gossypol, a cotton defensive chemical, was higher in pink bollworm larvae with cadherin resistance alleles than in larvae lacking such alleles. Adding gossypol to the larval diet decreased larval weight and survival, and increased the fitness cost affecting larval growth, but not survival. Across cadherin genotypes, the cost affecting larval growth increased as the gossypol concentration of larvae increased. These results suggest that increased accumulation of plant defensive chemicals may contribute to fitness costs associated with resistance to Bt toxins