Forces Shaping Research Articles

Fashion or function? Relaxed selection and stasis are key features of the evolution of stripes, bands and collars in Sceloporus lizards (Squamata: Phrynosomatidae)

Abstract Dorsal markings are common, and can function in predator evasion, as sexual signals, or be the remnants of developmental or physiological processes. We used phylogenetic comparative analyses to test whether black dorsal markings (stripes, bands or collars) on Sceloporus lizards reflect responses to different selective pressures over evolutionary time, or whether these markings have been linked in an integrated phenotype. We found that longitudinal striping evolved in small-bodied, terrestrial and egg-laying species, consistent with an antipredator function, especially when sexual selection was weak. Transverse bands evolved more slowly, and primarily in arboreal species, where they may enhance crypsis. Evolutionary shifts in collars were strongly linked to sexual size dimorphism, suggesting a function as sexual signals, and were tightly linked to parity mode. In two viviparous lineages, collars have been retained without loss for more than 12 Myr. Future studies are needed to determine whether this stasis is due to hormone transfer between females and their offspring or to other underlying physiological mechanisms. Our findings emphasize relaxed selection and stasis as important forces shaping the evolution of animal colours and signals.

Examining gender issues in education: exploring confounding experiences on three female educators’ professional knowledge landscapes

Business sources report that it will take 124 years for females to achieve parity in the workforce. Parity relates to compensation but also includes working conditions. The latter topic is taken up in this article using narrative inquiry as our method of investigation. Narrative inquiry—inquiring into narratives—employs three research tools: broadening, burrowing and storying/re-storying. To these tools, fictionalization, a fourth tool, is added. This is because the interwoven cases involve easily identifiable others and precautions need to be taken. This article discusses gender matters lived and told, and re-lived and re-told, over the career continuum of three women who have worked in public school and university settings. As females, they periodically encountered situations where they were perceived, interpreted, and responded to differently than males. The article looks at early, mid, and recent career challenges experienced in the female educators’ places of work. This research using narrative methods looks backward, forward, inside, and out through processes of individual and group reflection. It begins with bio-sketches, which were prepared individually. After that, the aforementioned research tools are used to unpack early, middle, and current career happenings. Reflective unpacking of the three females’ experiences within a community of critical friendship allowed for greater understanding and meaning-making to occur. The underlying intent of this work is to understand the shaping forces of gender on women’s professional lives—not to name and shame those who got away with acting the ways in which they did. The significance of the work lies in its use of narrative exemplars that are transparent, have a ring of authenticity to them, and promote trustworthiness and relatability when shared with others.

Quantifying drift-selection balance usingan agent-based biofilm model ofidentical heterotrophs under low-nutrient conditions.

Both deterministic and stochastic forces shape biofilm communities, but thebalance between those forces is variable. Quantifying the balance is both desirable and challenging. For example, drift-driven failure, astochastic force, can be thought of as an organism experiencing 'bad luck' and manipulating 'luck' as a factor in real-world systems is difficult. We used an agent-based model to manipulate luck by controlling seed cevalues governing random number generation. We determined which organism among identical competitors experienced the greatest drift-driven failure, gave it a deterministic growth advantage and re-ran the simulation with the same seed. This enabled quantifying the growth advantage required to overcome drift, e.g. a 50% chance to thrive may require a 10-20% improved growth rate. Further, we found that crowding intensity affected that balance. At moderate spacings, there were wide ranges where neither drift nor selection dominated. Those ranges shrank at extreme spacings; close and loose crowding, respectively, favoured drift and selection. We explain how these results may partially illuminate two conundrums: the fact that a stably operating wastewater treatment plant's microbial community can vary greatly over time and the difference between equivalent and total community size in neutral community assembly models.

Temporal dynamics of mother-offspring relationships in Bigg's killer whales: opportunities for kin-directed help by post-reproductive females.

Age-related changes in the patterns of local relatedness (kinship dynamics) can be a significant selective force shaping the evolution of life history and social behaviour. In humans and some species of toothed whales, average female relatedness increases with age, which can select for a prolonged post-reproductive lifespan in older females due to both costs of reproductive conflict and benefits of late-life helping of kin. Killer whales (Orcinus orca) provide a valuable system for exploring social dynamics related to such costs and benefits in a mammal with an extended post-reproductive female lifespan. We use more than 40 years of demographic and association data on the mammal-eating Bigg's killer whale to quantify how mother-offspring social relationships change with offspring age and identify opportunities for late-life helping and the potential for an intergenerational reproductive conflict. Our results suggest a high degree of male philopatry and female-biased budding dispersal in Bigg's killer whales, with some variability in the dispersal rate for both sexes. These patterns of dispersal provide opportunities for late-life helping particularly between mothers and their adult sons, while partly mitigating the costs of mother-daughter reproductive conflict. Our results provide an important step towards understanding why and how menopause has evolved in Bigg's killer whales.

Participatory design meets gender equality at European higher education institutions

ABSTRACT Gender equality is among the sustainable development goals expected of higher education institutions (HEIs). This paper will explore the potential and implications of participatory design (PD) in the context of gender equality work in HEIs. We study the topic within a multinational, multidisciplinary consortium, which is working for gender equality in HEIs, using PD as a tool and inspiration. We identify a variety of local conditions shaping PD and gender equality work, divergent discourses on gender equality work, and several sources of friction regarding PD and gender equality work. We conceptualise PD for gender equality work as being highly contested and emergent, with multiple forces shaping its trajectory. PD needs to be sensitive towards local circumstances at the national and organisational level, both politically and ideologically. It needs to navigate within national and international politics and policies and consider different timescales beyond specific projects. It also needs to acknowledge that PD for gender equality entails design, discourse, and friction.

Snakes on a plain: biotic and abiotic factors determine venom compositional variation in a wide-ranging generalist rattlesnake

BackgroundSnake venoms are trophic adaptations that represent an ideal model to examine the evolutionary factors that shape polymorphic traits under strong natural selection. Venom compositional variation is substantial within and among venomous snake species. However, the forces shaping this phenotypic complexity, as well as the potential integrated roles of biotic and abiotic factors, have received little attention. Here, we investigate geographic variation in venom composition in a wide-ranging rattlesnake (Crotalus viridis viridis) and contextualize this variation by investigating dietary, phylogenetic, and environmental variables that covary with venom.ResultsUsing shotgun proteomics, venom biochemical profiling, and lethality assays, we identify 2 distinct divergent phenotypes that characterize major axes of venom variation in this species: a myotoxin-rich phenotype and a snake venom metalloprotease (SVMP)-rich phenotype. We find that dietary availability and temperature-related abiotic factors are correlated with geographic trends in venom composition.ConclusionsOur findings highlight the potential for snake venoms to vary extensively within species, for this variation to be driven by biotic and abiotic factors, and for the importance of integrating biotic and abiotic variation for understanding complex trait evolution. Links between venom variation and variation in biotic and abiotic factors indicate that venom variation likely results from substantial geographic variation in selection regimes that determine the efficacy of venom phenotypes across populations and snake species. Our results highlight the cascading influence of abiotic factors on biotic factors that ultimately shape venom phenotype, providing evidence for a central role of local selection as a key driver of venom variation.

JamTac: A Tactile Jamming Gripper for Searching and Grasping in Low-Visibility Environments.

Humans can feel and grasp efficiently in the dark through tactile feedback, whereas it is still a challenging task for robots. In this research, we create a novel soft gripper named JamTac, which has high-resolution tactile perception, a large detection surface, and integrated sensing-grasping capability that can search and grasp in low-visibility environments. The gripper combines granular jamming and visuotactile perception technologies. Using the principle of refractive index matching, a refraction-free liquid-particle rationing scheme is developed, which makes the gripper itself to be an excellent tactile sensor without breaking its original grasping capability. We simultaneously acquire color and depth information inside the gripper, making it possible to sense the shape, texture, hardness, and contact force with high resolution. Experimental results demonstrate that JamTac can be a promising tool to search and grasp in situations when vision is not available.

Drivers of genomic landscapes of differentiation across a Populus divergence gradient.

Speciation, the continuous process by which new species form, is often investigated by looking at the variation of nucleotide diversity and differentiation across the genome (hereafter genomic landscapes). A key challenge lies in how to determine the main evolutionary forces at play shaping these patterns. One promising strategy, albeit little used to date, is to comparatively investigate these genomic landscapes as progression through time by using a series of species pairs along a divergence gradient. Here, we resequenced 201 whole-genomes from eight closely related Populus species, with pairs of species at different stages along the divergence gradient to learn more about speciation processes. Using population structure and ancestry analyses, we document extensive introgression between some species pairs, especially those with parapatric distributions. We further investigate genomic landscapes, focusing on within-species (i.e. nucleotide diversity and recombination rate) and among-species (i.e. relative and absolute divergence) summary statistics of diversity and divergence. We observe relatively conserved patterns of genomic divergence across species pairs. Independent of the stage across the divergence gradient, we find support for signatures of linked selection (i.e. the interaction between natural selection and genetic linkage) in shaping these genomic landscapes, along with gene flow and standing genetic variation. We highlight the importance of investigating genomic patterns on multiple species across a divergence gradient and discuss prospects to better understand the evolutionary forces shaping the genomic landscapes of diversity and differentiation.

Simultaneous Shape and Tip Force Sensing for the COAST Guidewire Robot.

Placement of catheters in minimally invasive cardiovascular procedures is preceded by navigating to the target lesion with a guidewire. Traversing through tortuous vascular pathways can be challenging without precise tip control, potentially resulting in the damage or perforation of blood vessels. To improve guidewire navigation, this paper presents 3D shape reconstruction and tip force sensing for the COaxially Aligned STeerable (COAST) guidewire robot using a triplet of adhered single core fiber Bragg grating sensors routed centrally through the robot's slender structure. Additionally, several shape reconstruction algorithms are compared, and shape measurements are utilized to enable tip force sensing. Demonstration of the capabilities of the robot is shown in free air where the shape of the robot is reconstructed with average errors less than at the guidewire tip, and the magnitudes of forces applied to the tip are estimated with an RMSE of or less.

Transnational students' experiences of EMI in Myanmar's borderlands

Based on a large-scale ethnography of Myanmar migrants, the present study examines the experiences of multilingual Myanmar students who received EMI education in secondary schools and universities in Myanmar's borderlands. Data were collected through the use of linguistic autobiography, semi-structured interviews and written materials. Adopting the borderlands theory, the study investigates how Myanmar ethnic minority students encounter and wrestle with the EMI learning challenges in the hybridized border regions. Our findings indicate that Myanmar ethnic minorities appropriate their agentive practices by leveraging their borderland subjectivities to form an assemblage of semioticized resources. Living in an under-resourced EMI context, our participants flexibly deploy their previous multiliteracies, mobilize the local and community resources and maximize the digital and transnational affordances. Our study argues that the successful validation of EMI prospect in the borderlands needs to overcome the essentialist practices and take into consideration sociopolitical power within and cross the border. By revealing the EMI affordances and constraints mediated in the transnational experiences, our study contributes to the knowledge base of EMI inquiry by including the peripheral voices and indigenous practices as legitimate construct and revealing the interplay of multiple forces shaping EMI students' trajectories.

Toward a sustainable urban regeneration? Urban heritage between neoliberal forces and community preferences

The paper discusses a relationship between the neoliberal forces shaping contemporary urban transformations and the social sustainability of recent regeneration projects focused on urban heritage. Analysing two post-transitional cases, based on two different approaches, the paper will provide an insight into the dominant processes influencing both practices, as well as their anticipated/announced social sustainability and its achieved level. The first case is from Serbia - the Power Plant “Power and Light” - which was the first one generating alternating current in Belgrade. Located in the Dorcol area, this ex-industrial setting is situated close to the city center. Since 2005, the entire area has undergone a significant transformation into a luxurious residential and commercial complex, initiated by private investors and directed by city authorities in order to change the previous urban image. The second case, the Contemporary Art Center in Plovdiv, Bulgaria, represents different approach. Created in 1997, the center is a non-governmental organisation of public interest. In 1995 the Municipality of Plovdiv obtained the right to locate the center within the remains of the ancient baths of Rome, which were rebuilt under the Turkish Empire. As the 16th century monument, the building belonged to the municipality and in 2004, the three-year period of support started, provided by the association Art Today (the Swiss cultural program), as well as the National Heritage Fund in Bulgaria. The analysis will be based on the selected principles of social sustainability, simultaneously highlighting the problems of heritage (re)use and regeneration in a challenging global environment of uncertain financial flows and shifting local governmental priorities, which could put on hold or totally ignore the aspect of social sustainability.

Biological properties, genetic structure and molecular variability of brome mosaic virus population

AbstractBrome mosaic virus (BMV) is a member of the Bromovirus genus in the Bromoviridae family. Due to its genetic and biochemical features, BMV is considered as one of the most important plant viruses in molecular plant pathology. Although BMV is widely used in many laboratories as a convenient model for molecular studies, knowledge regarding its biology, pathogenicity, virulence and genetic differentiation within natural populations is rather limited. In this study, the complete genome sequence of 16 BMV isolates originating from different hosts was obtained. Recombination, selection pressure and phylogenetic analyses were carried out using newly obtained BMV sequences and 10 others described to date. The nucleotide and amino acid sequence identities of the 26 BMV sequences were relatively high and ranged from 96.4% to 99.4% for nucleotide sequences and from 95.7% to 99.6% for amino acid sequences. Further analysis revealed that both selection and recombination are shaping the population structure of BMV. The presence of six possible recombination sites within open reading frames and one within the 3′ untranslated region of RNA2 was identified. Selection pressure analysis indicated that most codons were subjected to purifying selection; however, 14 codons were found to be under positive selection pressure. The results presented here expand the current knowledge regarding BMV diversity and the evolutionary forces shaping BMV population structure.

Upstream conduct and price authority with competing organizations

AbstractWe characterize the degree of price authority that competing upstream principals award their downstream agents in a setting where these agents own private information about demand and incur nonverifiable distribution costs. Principals cannot internalize these costs through monetary incentives and design “permission sets” from which agents choose prices. The objective is to understand the forces shaping delegation and the constraints imposed on equilibrium prices. When principals behave noncooperatively, agents are biased toward excessively high prices because they pass on distribution costs to consumers. Hence, the permission set only features a price cap that is more likely to bind as products become closer substitutes, in sectors where distribution is sufficiently costly, and when demand is not too volatile. By contrast, when principals behave cooperatively, the optimal delegation scheme is richer and more complex. Because principals want to charge the monopoly price, the optimal permission set features a price floor when the distribution cost is sufficiently low, it features instead full discretion for moderate values of this cost, and only when it is high enough, a price cap is optimal. Surprisingly, while competition (as captured by stronger product substitutability) hinders delegation in the noncooperative regime, the opposite occurs when principals maximize industry profit.

COMPARATIVE ANALYSIS OF UKRAINIAN AND GERMAN HIGHER EDUCATION SYSTEMS: EXPLORING CONTRASTS AND POTENTIAL COLLABORATIVE ENDEAVORS IN PROFESSIONAL PEDAGOGY

This research article presents a comprehensive comparative analysis of the Ukrainian and German higher education systems, examining their distinctive characteristics and potential for collaboration in the field of professional pedagogy. The study delves into the structural variances, global rankings, admission requirements, tuition fees, research and innovation landscapes, internationalization efforts, and partnership prospects. By critically examining these aspects, this research contributes to the scholarly discourse on comparative education and professional pedagogy, shedding light on the significance of cross-national collaboration in shaping the future of higher education.
 In this article, we conducted a comprehensive review of academic literature, reports, studies, and relevant documents on the Ukrainian and German higher education systems, examined official documents, policies, and regulations from relevant governmental and educational bodies in both countries, utilized statistical data available from official sources, educational institutions, and international organizations to quantify and compare various aspects of the education systems, such as enrolment numbers, program offerings, research output, and internationalization efforts. 
 In a larger scholarly context, this research makes a significant contribution to the discourse on comparative education and professional pedagogy. By adroitly navigating and dissecting the multifaceted domains of both systems, the research lays bare the underlying dynamics that shape their educational paradigms. The illumination of cross-national collaboration as an instrumental force in shaping the trajectory of higher education underscores the article's scholarly import. To sum up, this research advances the understanding of both systems, envisages novel collaborative trajectories, and underscores the scholarly imperative of cross-nation cooperation in shaping the future contours of higher education.

Effect of internal damping on locomotion in frictional environments.

The gaits of undulating animals arise from a complex interaction of their central nervous system, muscle, connective tissue, bone, and environment. As a simplifying assumption, many previous studies have often assumed that sufficient internal force is available to produce observed kinematics, thus not focusing on quantifying the interconnection between muscle effort, body shape, and external reaction forces. This interplay, however, is critical to locomotion performance in crawling animals, especially when accompanied by body viscoelasticity. Moreover, in bioinspired robotic applications, the body's internal damping is indeed a parameter that the designer can tune. Still, the effect of internal damping is not well understood. This study explores how internal damping affects the locomotion performance of a crawler with a continuous, viscoelastic, nonlinear beam model. Crawler muscle actuation is modeled as a traveling wave of bending moment propagating posteriorly along the body. Consistent with the friction properties of the scales of snakes and limbless lizards, environmental forces are modeled using anisotropic Coulomb friction. It is found that by varying the crawler body's internal damping, the crawler's performance can be altered, and distinct gaits could be achieved, including changing the net locomotion direction from forward to back. We will discuss this forward and backward control and identify the optimal internal damping for peak crawling speed.

From transactions to transformations: exploring transformative food retailing

ABSTRACT Food retailing is undergoing a major restructuring process that is altering its boundaries, service provision and operations. Digitalisation and other technological advances are shifting the focus from products to services, from offline to online and from physical to virtual. Simultaneously, initiatives such as the United Nations Sustainable Development Goals are exerting pressure on food retailers to address contemporary global challenges, such as promoting healthy and sustainable consumption and production. However, these areas not only challenge food retailers but also provide opportunities for facilitating favourable dietary changes that benefit consumers, companies and society at large. This study introduces transformative food retailing as a construct that shifts attention to the reconfigured role of food retailing and its potential. We identify the shaping forces and characteristics of transformative food retailing and discuss the implications for consumers, food retailers and society at large. This paper is among the first to define and conceptualise food retail as transformative and, as a result, sets a platform for future scholarly research and practice to uncover the full potential of food retailing in serving both consumers and society.

The growth of the buccal mass in Sepia officinalis: functional changes throughout ontogeny

Due to their small size, juveniles are more likely to show lower absolute levels of performance leading to a potential competitive disadvantage compared to adults. Therefore, juveniles are expected to compensate by showing a higher relative performance, and/or partitioning resources to overcome this performance disadvantage. Here, we investigate the link between ontogeny and feeding performance in the common cuttlefish Sepia officinalis. We explore the changes in beak shape, wear pattern, mechanical properties, muscular anatomy, and bite force during growth from 3-month post hatching to adults. We show that both upper and lower beaks present important ontogenetic shape variation in the rostrum area that might be due to wear induced by feeding. The mechanical properties of the beaks in juveniles indicate greater resistance compared to adults. Tanning observed on the beaks provides reinforcement to areas under high load during biting. In addition, muscle development and relative bite force were found to differ between cuttlefish of different ages, resulting in juveniles having a similar bite force for their size but with a muscular advantage for opening. Finally, an isometric relation is found in the bite force of S. officinalis, with no sign of feeding performance compensation in juveniles. Feeding performance thus does not reflect the ontogenetic shift from a crustacean-based diet in juveniles to a fish-based diet in adults.

World population growth over millennia: Ancient and present phases with a temporary halt in-between

Enormous growth of the world population during the last two centuries and its present slowing down pose questions about precedents in history and broader forces shaping the population size. Population estimates collected in an extensive survey of literature (873 estimates from 25 studies covering 1,000,000 BCE to 2100 CE) show that world population growth has proceeded in two distinct phases of acceleration followed by stoppage—from at least 25,000 BCE to 100 BCE, and from 400 CE to the present, interrupted by centuries of standstill and 10% decrease. Both phases can be fitted with a mathematical function that projects to a peak at 11.2 ± 1.5 billion around 2100 CE. An interaction model can account for this acceleration-stoppage pattern in quantitative detail: Technology grows exponentially, with rate boosted by population. Population grows exponentially, capped by Earth’s carrying capacity. Technology raises this cap, but only until it approaches Earth’s ultimate carrying capacity.

Two-Dimensional Shape and Distal Force Estimation for the Continuum Robot Based on Learning From the Proximal Sensors

Accurate shape sensing and distal contact force estimation of the flexible continuum robots remains challenging due to critical hysteresis profiles for modeling and the difficulties on sensor integration at their distal ends. This paper proposes a learning-based approach to predict distal-tip interaction information by solely utilizing the sensory measurements from the proximal end. A workflow including multilayer perception (MLP) and long short-term memory (LSTM) was investigated to simultaneously estimate and predict the whole shape and distal contact force. Experiments were carried out on a typical single-section continuum robot to verify the effectiveness of the proposed method. The proposed method could achieve high accuracy of root mean square error (RMSE) =0.26 N for force prediction and a relative error of less than 1.2% for shape estimation. Notably, the LSTM-based method could precisely identify the force hysteresis profile. In summary, the proposed framework could be applied to the cable-drive continuum robotic systems for precise contact force and shape feedback without requiring sensors at the distal tip.

Evolution of loss of heterozygosity patterns in hybrid genomes of Candida yeast pathogens

BackgroundHybrids are chimeric organisms with highly plastic heterozygous genomes that may confer unique traits enabling the adaptation to new environments. However, most evolutionary theory frameworks predict that the high levels of genetic heterozygosity present in hybrids from divergent parents are likely to result in numerous deleterious epistatic interactions. Under this scenario, selection is expected to favor recombination events resulting in loss of heterozygosity (LOH) affecting genes involved in such negative interactions. Nevertheless, it is so far unknown whether this phenomenon actually drives genomic evolution in natural populations of hybrids. To determine the balance between selection and drift in the evolution of LOH patterns in natural yeast hybrids, we analyzed the genomic sequences from fifty-five hybrid strains of the pathogenic yeasts Candida orthopsilosis and Candida metapsilosis, which derived from at least six distinct natural hybridization events.ResultsWe found that, although LOH patterns in independent hybrid clades share some level of convergence that would not be expected from random occurrence, there is an apparent lack of strong functional selection. Moreover, while mitosis is associated with a limited number of inter-homeologous chromosome recombinations in these genomes, induced DNA breaks seem to increase the LOH rate. We also found that LOH does not accumulate linearly with time in these hybrids. Furthermore, some C. orthopsilosis hybrids present LOH patterns compatible with footprints of meiotic recombination. These meiotic-like patterns are at odds with a lack of evidence of sexual recombination and with our inability to experimentally induce sporulation in these hybrids.ConclusionsOur results suggest that genetic drift is the prevailing force shaping LOH patterns in these hybrid genomes. Moreover, the observed LOH patterns suggest that these are likely not the result of continuous accumulation of sporadic events—as expected by mitotic repair of rare chromosomal breaks—but rather of acute episodes involving many LOH events in a short period of time.