Thorlief Schjelderup-Ebbe's seminal paper on the 'pecking' order of chickens inspired numerous ethologists to research and debate the phenomenon of dominance. The expansion of dominance to the ...broader concept of power facilitated disentangling aggression, strength, rank and power. Aggression is only one means of coercing other individuals, and can sometimes highlight a lack of power. The fitness advantages of aggression may only outweigh the costs during periods of uncertainty. Effective instruments of power also include incentives and refusals to act. Moreover, the stability of the power relationship might vary with the instruments used if different means of power vary in the number and types of outcomes achieved, as well as the speed of accomplishing those outcomes. In well-established relationships, actions or physiological responses in the subordinate individual may even be the only indicator of a power differential. A focus on strength, aggression and fighting provides an incomplete understanding of the power landscape that individuals actually experience. Multiple methods for constructing hierarchies exist but greater attention to the implications of the types of data used in these constructions is needed. Many shifts in our understanding of power were foreshadowed in Schjelderup-Ebbe's discussion about deviations from the linear hierarchy in chickens. This article is part of the theme issue 'The centennial of the pecking order: current state and future prospects for the study of dominance hierarchies'.
Sex-biased power structures are common in human and nonhuman primate societies. "Female dominance" is a term applied to a wide range of female-biased power structures. However, the full extent of ...this variation remains obscure because an adequate vocabulary of power has not been adopted consistently. Female power occurs throughout primates and other animals, even in male-dominant societies, but the legacy of patriarchy persists in primatologists' use of language and implicit assumptions about intersexual power. While explanations for the occurrence of female power can be accommodated within existing ethological theory, many hypotheses seeking to explain the evolution of female power are narrowly focused on particular taxa. Theories about primate social evolution would benefit from a synthesis of the disparate literature on power, increased emphasis on intersexual social relationships, and comparative studies that include the full behavioral diversity of primates and other mammals.
Over the past decade several studies have reported that the gut microbiomes of mammals with similar dietary niches exhibit similar compositional and functional traits. However, these studies rely ...heavily on samples from captive individuals and often confound host phylogeny, gut morphology, and diet. To more explicitly test the influence of host dietary niche on the mammalian gut microbiome we use 16S rRNA gene amplicon sequencing and shotgun metagenomics to compare the gut microbiota of 18 species of wild non-human primates classified as either folivores or closely related non-folivores, evenly distributed throughout the primate order and representing a range of gut morphological specializations. While folivory results in some convergent microbial traits, collectively we show that the influence of host phylogeny on both gut microbial composition and function is much stronger than that of host dietary niche. This pattern does not result from differences in host geographic location or actual dietary intake at the time of sampling, but instead appears to result from differences in host physiology. These findings indicate that mammalian gut microbiome plasticity in response to dietary shifts over both the lifespan of an individual host and the evolutionary history of a given host species is constrained by host physiological evolution. Therefore, the gut microbiome cannot be considered separately from host physiology when describing host nutritional strategies and the emergence of host dietary niches.
Objectives
Unidirectional dominance‐related signals can be used to communicate submission (an immediate behavioral response) or subordination (the status of an established relationship). ...Subordination signals are defined as emitted during peaceful interactions and are hypothesized to be critical for the evolution of social complexity and robust power structures because they reduce uncertainty in social relationships. The chatter vocalization in Verreaux's sifaka (Propithecus verreauxi) is a unidirectional submissive signal. I tested the hypothesis that chatter vocalizations can signal subordination and thereby reduce agonism in a dyad.
Materials and Methods
I examined 780 chatters from 18 dyads collected over 881 observation hours on four groups of sifaka in Kirindy Forest, Madagascar.
Results
Sifaka emitted 63% of chatters in the peaceful context. Peaceful chatters significantly predicted grooming rate, fighting rate, reconciliation, and proportion of wins in a dyad but did not predict time in proximity. Dyad‐type significantly predicted the frequency of peaceful chatters, with intrasexual dyads exhibiting chatters in peaceful contexts more often than intersexual dyads.
Discussion
Sifaka communicate both submission and subordination with chatter vocalizations. Subordination signaling increased tolerance and affiliation. It reduced conflicts and the probability dominant individuals usurped resources. Moreover, intrasexual power may be more institutionalized than intersexual power in sifaka. The finding of complex and cognitively demanding social communication in a lemur with low levels of cooperation (1) challenges previous assumptions that the evolution of social complexity is dependent on frequent triadic interactions and high levels of cooperation, and (2) highlights the need for taxonomic diversity in studies of social complexity.
Female dominance is often associated with lemurs. However, consensus does not exist among primatologists on how to define, measure, or explain female dominance. This review explores the utility of ...applying a broader concept of power to understanding lemur intersexual relationships. In this framework, power is defined as arising from an asymmetry in a dyadic relationship and can be divided into 2 types: dominance and leverage. Intersexual asymmetries based upon females having superior fighting ability are considered female dominance. However, economic power also exists, and females with resource-based power exhibit female leverage. Additionally, power has 4 characteristics (base, means, amount, and scope) that describe the precise nature of observed phenomena. This article utilizes the 4 characteristics outlined in the power framework to review the existing "female dominance" literature for lemurs and highlights the value of adopting both an expanded concept of power and a more precise language. By placing the multiple phenomena currently labeled under the single term "female dominance" within the power framework, much of the confusion disappears. Thus, not only is the debate reframed, facilitating endeavors to find evolutionary explanations, but the uniqueness of female power in lemurs can be determined empirically rather than by definition.
Damage to auditory hair cells is a key feature of sensorineural hearing loss due to aging, noise exposure, or ototoxic drugs. Though hair-cell loss is permanent in humans, research in bird species ...led to the discovery that analogous hair cells of the avian basilar papilla are able to regenerate after being damaged by ototoxic agents. Regeneration appears to occur through a combination of the mitotic expansion of a precursor population of supporting cells and direct transdifferentiation of supporting cells into functioning hair cells. This review will synthesize the relevant anatomy and pathophysiology of sensorineural hearing loss, the historical observations that led to the genesis of the hair-cell regeneration field, and perspectives on initial human hair-cell regeneration trials.
Head and neck cancers, including those of the lip and oral cavity, nasal cavity, paranasal sinuses, oropharynx, larynx and nasopharynx represent nearly 700,000 new cases and 380,000 deaths worldwide ...per annum, and account for over 10,000 annual deaths in the United States alone. Improvement in outcomes are needed for patients with recurrent and or metastatic squamous cell carcinoma of the head and neck (HNSCC). In 2016, the US Food and Drug Administration (FDA) granted the first immunotherapeutic approvals - the anti-PD-1 immune checkpoint inhibitors nivolumab and pembrolizumab - for the treatment of patients with recurrent squamous cell carcinoma of the head and neck (HNSCC) that is refractory to platinum-based regimens. The European Commission followed in 2017 with approval of nivolumab for treatment of the same patient population, and shortly thereafter with approval of pembrolizumab monotherapy for the treatment of recurrent or metastatic HNSCC in adults whose tumors express PD-L1 with a ≥ 50% tumor proportion score and have progressed on or after platinum-containing chemotherapy. Then in 2019, the FDA granted approval for PD-1 inhibition as first-line treatment for patients with metastatic or unresectable, recurrent HNSCC, approving pembrolizumab in combination with platinum and fluorouracil for all patients with HNSCC and pembrolizumab as a single agent for patients with HNSCC whose tumors express a PD-L1 combined positive score ≥ 1. These approvals marked the first new therapies for these patients since 2006, as well as the first immunotherapeutic approvals in this disease. In light of the introduction of these novel therapies for the treatment of patients with head and neck cancer, The Society for Immunotherapy of Cancer (SITC) formed an expert committee tasked with generating consensus recommendations for emerging immunotherapies, including appropriate patient selection, therapy sequence, response monitoring, adverse event management, and biomarker testing. These consensus guidelines serve as a foundation to assist clinicians' understanding of the role of immunotherapies in this disease setting, and to standardize utilization across the field for patient benefit. Due to country-specific variances in approvals, availability and regulations regarding the discussed agents, this panel focused solely on FDA-approved drugs for the treatment of patients in the U.S.
The gut microbiomes of mammals appear to mirror their hosts' phylogeny, suggesting host-driven microbial community assembly. Yet, much of this evidence stems from comparative studies of distinct wild ...or captive populations that lack data for disentangling the relative influences of shared phylogeny and environment. Here, we present phylogenetic and multivariate analyses of gut microbiomes from six sympatric (i.e., co-occurring) mammal species inhabiting a 1-km
area in western Madagascar-three lemur and three non-primate species-that consider genetic, dietary, and ecological predictors of microbiome functionality and composition. Host evolutionary history, indeed, appears to shape gut microbial patterns among both closely and distantly related species. However, we also find that diet-reliance on leaves versus fruit-is the best predictor of microbiome similarity among closely related lemur species, and that host substrate use-ground versus tree-constrains horizontal transmission via incidental contact with feces, with arboreal species harboring far more distinct communities than those of their terrestrial and semi-terrestrial counterparts.
In wild primates, social behaviour influences exposure to environmentally acquired and directly transmitted microorganisms. Prior studies indicate that gut microbiota reflect pairwise social ...interactions among chimpanzee and baboon hosts. Here, we demonstrate that higher-order social network structure—beyond just pairwise interactions—drives gut bacterial composition in wild lemurs, which live in smaller and more cohesive groups than previously studied anthropoid species. Using 16S rRNA gene sequencing and social network analysis of grooming contacts, we estimate the relative impacts of hierarchical (i.e. multilevel) social structure, individual demographic traits, diet, scent-marking, and habitat overlap on bacteria acquisition in a wild population of Verreaux's sifaka (Propithecus verreauxi) consisting of seven social groups. We show that social group membership is clearly reflected in the microbiomes of individual sifaka, and that social groups with denser grooming networks have more homogeneous gut microbial compositions. Within social groups, adults, more gregarious individuals, and individuals that scent-mark frequently harbour the greatest microbial diversity. Thus, the community structure of wild lemurs governs symbiotic relationships by constraining transmission between hosts and partitioning environmental exposure to microorganisms. This social cultivation of mutualistic gut flora may be an evolutionary benefit of tight-knit group living.
Purpose
Most survivors of childhood cancer experience subsequent chronic conditions but little is known about concurrent symptoms. This study seeks to identify late effect symptom clusters among ...young pediatric cancer survivors.
Methods
Survivors ≥ 18 or parents of survivors < 18 years enrolled in an institutional cohort study indicated (yes/no) if they experienced certain symptoms after treatment. The sample was randomly divided in half for exploratory factor analyses to identify symptom clusters followed by confirmatory factor analyses. Symptoms with ≥ 10% prevalence were included. Cluster structure generalizability across subgroups was examined using congruence coefficients.
Results
The sample included 579 survivors (74% non-Hispanic white, 45% leukemia, 12.8 ± 4.5 years at survey, 5.9 ± 3.5 years since therapy). Respondents averaged three symptoms. Three clusters were identified: (1) gastrointestinal: abdominal pain, diarrhea, constipation, nausea, vomiting (Cronbach’s
α
= 0.74); (2) psychological: depression, anxiety, memory problems, anger management problems, sleep problems (
α
= 0.71); and (3) neurologic: problems walking, numbness/tingling, fatigue, back pain, chronic pain, weakness/inability to move legs (
α
= 0.71). Confirmatory factor analysis confirmed the three-cluster structure (standardized root mean square residual: 0.09; parsimonious goodness of fit: 0.96; Bentler-Bonett normed fit index: 0.95). The gastrointestinal and psychological clusters were generalizable across most subgroups while the neurologic cluster varied across age and race/ethnicity subgroups.
Conclusion
Three distinct late effect symptom clusters were identified in young childhood cancer survivors with gastrointestinal and psychological clusters remaining relatively stable across subgroups. Future studies should focus on the characteristics of patients who experience these symptoms, especially those with high symptom burden, and the synergistic impact on quality of life.
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