Lanchester's models of combat have been invoked to explain the mechanics of group fighting in social animals. Specifically, Lanchester's square law posits that the fighting ability of the group is ...proportional to the square of the number of combatants. Although used to explain a variety of ecological phenomena, the models have not been thoroughly tested. We tested the Lanchester models using group battles between colonies of the termite
. Our main goals were to determine if mortality rates fit the Lanchester models, and if so, whether the behavioural mechanisms underlying a group's success match those used in deriving the model. We initiated battles between pairs of colonies with different ratios of fighters and recorded deaths over time. We found that the numerically larger army has an advantage, but that the advantage is not as pronounced as predicted by Lanchester's square law. We also video-recorded battles to analyse individual behaviour, which did not support the mechanisms invoked by Lanchester. Instead, the killing power of an individual is increased by the presence of nest-mates, giving the larger group a disproportionate advantage. Although the behavioural mechanisms leading to the advantage may differ, our results still support some of the proposed ecological phenomena.
Polyploidal giant cancer cells (PGCCs) have been observed by pathologists in patient tumor samples and are especially prominent in late stage, high grade disease or after chemotherapy. However, they ...are often overlooked due to their apparent dormancy. Recent research has shown PGCCs to be chemoresistant and express stem-like features, traits associated with disease progression and relapse. Here, we show the preferential survival of PGCCs during Paclitaxel (PTX) treatment and used multiple particle tracking analysis to probe their unique biophysical phenotype. We show that PGCCs have higher inherent cytoplasmic and nuclear stiffness in order to withstand the mechanical stress associated with their increased size and the chemical stress from PTX treatment. Inhibitor studies show the involvement of a dysregulated RhoA-Rock1 pathway and overall actin cytoskeletal network as the underlying mechanism for the altered biophysical phenotype of PGCCs. Furthermore, PGCCs exhibit a slow but persistent migratory phenotype, a trait commonly associated with metastatic dissemination and invasiveness. This work demonstrates the clinical relevance and the need to study this subpopulation, in order to devise therapeutic strategies to combat disease relapse. By highlighting the unique biophysical phenotype of PGCCs, we hope to provide unique avenues for therapeutic targeting of these cells in disease treatment.
Almost 40 years ago, Terry L. Erwin published a seemingly audacious proposition: There may be as many as 30 million species of insects in the world. Here, we translate Erwin's verbal argument into a ...diversity‐ratio model—the Erwin Equation of Biodiversity—and discuss how it has inspired other biodiversity estimates. We categorize, describe the assumptions for, and summarize the most commonly used methods for calculating estimates of global biodiversity. Subsequent diversity‐ratio extrapolations have incorporated parameters representing empirical insect specialization ratios, and how insect specialization changes at different spatial scales. Other approaches include macroecological diversity models and diversity curves. For many insect groups with poorly known taxonomies, diversity estimates are based on the opinions of taxonomic experts. We illustrate our current understanding of insect diversity by focusing on the six most speciose insect orders worldwide. For each order, we compiled estimates of the (a) maximum estimated number of species, (b) minimum estimated number of species, and (c) number of currently described species. By integrating these approaches and considering new information, we believe an estimate of 5.5 million species of insects in the world is much too low. New molecular methodologies (e.g., metabarcoding and NGS studies) are revealing daunting numbers of cryptic and previously undescribed species, at the same time increasing our precision but also uncertainty about present estimates. Not until technologies advance and sampling become more comprehensive, especially of tropical biotas, will we be able to make robust estimates of the total number of insect species on Earth.
in Spanish is available with online material.
➨Resumen
Hace casi cuarenta años, Terry L. Erwin publicó una propuesta aparentemente audaz: podrían existir hasta 30 millones de especies de insectos en el mundo. Aquí traducimos el argumento verbal de Erwin en un modelo de diversidad, la Ecuación de Biodiversidad de Erwin, y discutimos cómo ha inspirado otros estimados de biodiversidad. Clasificamos y describimos los supuestos, y resumimos los métodos más utilizados para calcular la biodiversidad global. Nuevas extrapolaciones de la relación de diversidad han incorporado parámetros que representan las relaciones empíricas de especialización de insectos y cómo cambia esa especialización en diferentes escalas espaciales. Otros enfoques incluyen modelos de diversidad macroecológica y curvas de diversidad. Para muchos grupos de insectos con taxonomías poco conocidas, las estimaciones de diversidad se basan en las opiniones de expertos en taxonomía. Ilustramos nuestra comprensión actual de la diversidad de insectos enfocándonos en los seis órdenes de insectos con más especies del mundo. Para cada orden, compilamos (1) el número máximo estimado de especies, (2) el número mínimo estimado de especies y (3) el número de especies descritas actualmente. Al integrar estos enfoques y considerar nueva información, creemos que el estimado de 5,5 millones de especies de insectos en el mundo es demasiado bajo. Nuevos métodos moleculares (p. Ej., Metabarcoding y estudios NGS) revelan miles de especies crípticas y especies no descritas anteriormente, al mismo tiempo que aumentan nuestra precisión, pero también la incertidumbre sobre los estimados actuales. No será hasta que las tecnologías avancen y el muestreo sea más exhaustivo, especialmente en las biotas tropicales, que podríamos proponer estimados sólidos del número total de especies de insectos en la Tierra.
The Lanchester models of combat were originally created for human warfare. These models were inspired by advances in technology and automatic weaponry at the turn of the 20th century. They ...parameterize army group size and individual fighting ability to explain the mortality rate of soldiers in a group during battle. In the last few decades, they have been applied to conflicts involving interactions between groups of nonhuman animals of varying degrees of sociality. This review focuses on the predictions and applications of Lanchester laws to nonhuman animal contests. Behavioral researchers have used the Lanchester models to interpret a variety of life history strategies and behaviors, such as colony fission in army ants, size differences in native versus non-native ants, recruitment behavior in chimpanzees, and dominance hierarchies in birds. These researchers assumed that the Lanchester laws apply qualitatively, and sometimes quantitatively, to the specific circumstances studied. To increase their biological realism, mathematical modifications have been proposed. While applications suggest that these laws may explain a multitude of social behaviors, there are surprisingly few empirical tests. Thus, further empirical data are needed to fully assess the accuracy of the models in predicting outcomes in nonhuman animals and their usefulness to biological systems.
In this paper, we discuss two complementary commitments of interpretative phenomenological analysis (IPA): the phenomenological requirement to understand and 'give voice' to the concerns of ...participants; and the interpretative requirement to contextualize and 'make sense' of these claims and concerns from a psychological perspective. The methodological and conceptual bases for the relationship between these phenomenological and interpretative aspects of IPA appear to be underdeveloped in the literature. We, therefore, offer some thoughts on the basis of this relationship, and on its context within qualitative psychology. We discuss the epistemological range of IPA's interpretative focus, and its relationship to the more descriptive features of phenomenological analysis. In order to situate our conclusions within a contextualist position, we draw upon concepts from Heideggerian phenomenology. The argument is illustrated by excerpts from our own research on relationship break-up. We conclude by encouraging IPA researchers to embrace the interpretative opportunities that are offered by this approach.
Recently discovered bacteria and archaea adaptive immune system consisting of clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated (Cas) endonuclease has been ...explored in targeted genome editing in different species.Streptococcus pyogenesCas9-guide RNA (gRNA) was successfully applied to generate targeted mutagenesis, gene integration, and gene editing in soybean (Glycine max). Two genomic sites,DD20andDD43on chromosome 4, were mutagenized with frequencies of 59% and 76%, respectively. Sequencing randomly selected transgenic events confirmed that the genome modifications were specific to the Cas9-gRNA cleavage sites and consisted of small deletions or insertions. Targeted gene integrations through homology-directed recombination were detected by border-specific polymerase chain reaction analysis for both sites at callus stage, and oneDD43homology-directed recombination event was transmitted to T1 generation. T1 progenies of the integration event segregated according to Mendelian laws and clean homozygous T1 plants with the donor gene precisely inserted at theDD43target site were obtained. The Cas9-gRNA system was also successfully applied to make a directed P178S mutation of acetolactate synthase1 gene through in planta gene editing.
Wildfire impacts ecosystems, climate, carbon cycling, societies, and human health. Quantification of these impacts relies upon climate and fire models, which are constrained by historical ...observations that are limited to the past 30 years. But in regions where records are sparse, like Equatorial Asia (EQAS), fire activities are assumed to be insignificant before the 1960s. We present a 200-year charcoal record from Lake Lading, Indonesia, which shows substantial fire variability since the 19th century. We identify a significant role of humans in controlling fire activity in Java, which could potentially extend to other parts of EQAS. These results contradict assumptions made in current fire emissions estimates and suggest an oversimplification of the spatiotemporal complexity of fire in EQAS before the 1960s. Our study highlights the need for more high-resolution charcoal records in the tropics to improve fire models and emissions estimates.
•There are very few paleofire records from Equatorial Asia.•This makes estimating burning and benchmarking fire models for this region difficult.•We present a new, charcoal-based paleofire record from East Java.•Our record challenges assumptions about fire’s controls.•Fire in Equatorial Asia did not respond to climate and population growth uniformly.
Two opposing forces, competition and cooperation, play vital roles in the evolution of social behavior. Cooperation enables members of social groups to split up tasks, share food, and protect each ...other. However, groups may also be more prone to competition and predation, as they take up more space and are easier for predators to spot. My work focuses on the defenses social groups have evolved to protect themselves during conflict. Termites provide an ideal system for studying group defense, as their soldier caste, which serves to protect the colony, was one of the first sterile castes to evolve.My initial work used termites to study models of combat based on human warfare, due to termites’ affinity for large, deadly battles. Then, I shifted to more closely study the evolution of termite defenses. My first three chapters analyze Lanchester’s models of combat, which parameterize group size and individual fighting ability to determine the winner of a battle. I staged battles of 50 termites and varied initial group size and group pairings. With collaborators, I analyzed the mortality from these battles to determine if the dynamics if the Lanchester models. I found that group size may weigh heavily in the outcome of intraspecific battles, but interspecific battles have a complicated trade-off between group size and individual fighting ability. I also proposed and found intraspecific support for the synergistic attack hypothesis, which posits that the killing ability of an individual is increased by the presence of its nestmates.My final chapter is a case study of a bizarre defensive adaptation I observed during interspecific battle trials: self-rupturing behavior. Through behavioral assays and microscopy work, I discovered that Cylindrotermes macorgnathus workers self-rupture when threatened and compared their anatomy to their closest relatives, Cephalotermes rectangularis, which don’t rupture. Overall, this dissertation covers the quantitative and qualitative aspects of group fighting and defense in termites.
Background
Globally, stress in student nurses may have serious implications for health, absenteeism, and attrition. Despite this, there is scant research on student nurses' attitudes toward help ...seeking.
Objectives
To examine student nurses' attitudes toward stress and help‐seeking.
Design Methods and Statistical Analysis
A cross‐sectional questionnaire survey design was employed to gather data from 219 student nurses at two large U.K. universities. Two‐sample chi‐square tests and Fisher's exact tests were used to analyze categorical associations between responses.
Results
Most had experienced stress before, believed the incidence within the profession was high, and would disclose their own stress to family/friends rather than to colleagues or professional institutions. The most popular outpatient treatment choice was social support; few would choose formal advice. The most common factor influencing inpatient treatment choice was confidentiality; for many, this factor would also lead them to seek distant rather than local inpatient care. Encouragingly, most would not lose confidence in a stressed colleague.
Conclusions
Negative attitudes toward stress and help seeking may be entrenched even before training and may have a marked influence on how/whether students seek help. Nurse employers and educators should foster more supportive and accepting attitudes toward stress in order to tackle its unwanted consequences.
Galbraith
Brown
Clifton
According to the focal concerns perspective, the concerns guiding judges’ sentencing considerations are blameworthiness and harm, community protection, and practical considerations. Regarding racial ...and other disparities in sentencing, focal concerns contend that various constraints, associations between defendants’ demographic characteristics, and the three focal concerns influence judicial decision-making. One association that is explored infrequently is the institutionalization decision of juveniles and how that decision is associated with race and various school-based metrics. Using a sample of adjudicated delinquent juveniles from one state over a 5-year period and merged with American Community Survey data, the present study explores how school factors alongside race serve as focal concerns for judges, impacting the decision to institutionalize juveniles.
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