Population size impacts host–pathogen coevolution

Ongoing host–pathogen interactions are characterized by rapid coevolutionary changes forcing species to continuously adapt to each other. The interacting species are often defined by finite population sizes. In theory, finite population size limits genetic diversity and compromises the efficiency of selection owing to genetic drift, in turn constraining any rapid coevolutionary responses. To date, however, experimental evidence for such constraints is scarce. The aim of our study was to assess to what extent population size influences the dynamics of host–pathogen coevolution. We used Caenorhabditus elegans and its pathogen Bacillus thuringiensis as a model for experimental coevolution in small and large host populations, as well as in host populations which were periodically forced through a bottleneck. By carefully controlling host population size for 23 host generations, we found that host adaptation was constrained in small populations and to a lesser extent in the bottlenecked populations. As a result, coevolution in large and small populations gave rise to different selection dynamics and produced different patterns of host–pathogen genotype-by-genotype interactions. Our results demonstrate a major influence of host population size on the ability of the antagonists to co-adapt to each other, thereby shaping the dynamics of antagonistic coevolution.

Modelling ocean acidification effects with life stage-specific responses alters spatiotemporal patterns of catch and revenues of American lobster, Homarus americanus

Ocean acidification (OA) affects marine organisms through various physiological and biological processes, yet our understanding of how these translate to large-scale population effects remains limited. Here, we integrated laboratory-based experimental results on the life history and physiological responses to OA of the American lobster, Homarus americanus, into a dynamic bioclimatic envelope model to project future climate change effects on species distribution, abundance, and fisheries catch potential. Ocean acidification effects on juvenile stages had the largest stage-specific impacts on the population, while cumulative effects across life stages significantly exerted the greatest impacts, albeit quite minimal. Reducing fishing pressure leads to overall increases in population abundance while setting minimum size limits also results in more higher-priced market-sized lobsters (> 1 lb), and could help mitigate the negative impacts of OA and concurrent stressors (warming, deoxygenation). However, the magnitude of increased effects of climate change overweighs any moderate population gains made by changes in fishing pressure and size limits, reinforcing that reducing greenhouse gas emissions is most pressing and that climate-adaptive fisheries management is necessary as a secondary role to ensure population resiliency. We suggest possible strategies to mitigate impacts by preserving important population demographics.

ESL Programs in Rural High Schools: Challenges and Opportunities

Rural and small-town communities in the United States have been rapidly diversifying over the last few decades and rural schools have faced challenges in supporting changing populations. This article builds on a limited body of education research that has focused on diversity in rural areas, driven largely in the U.S. by Latinx immigrant populations. This research draws on several data sources from multi-week visits in a mixture of new and established immigrant destinations to profile the challenges educational leaders faced developing ESL programs in five rural high schools and explores challenges such as how schools struggle to recruit and retain administrators and teachers, how they often have limited knowledge and resources to support curriculum development, and how program size limits schools’ ability to place students appropriately. The article concludes with suggestions for education programs, rural administrators, and state policy makers to better support English learners in rural schools.

The Ecology of Palm Genomes: Repeat-associated genome size expansion is constrained by aridity

Genome size varies 2,400-fold across plants, influencing their evolution through changes in cell size and cell division rates which impact plants' environmental stress tolerance. Repetitive element expansion explains much genome size diversity, and the processes structuring repeat 'communities' are analogous to those structuring ecological communities. However, which environmental stressors influence repeat community dynamics has not yet been examined from an ecological perspective. We measured genome size and leveraged climatic data for 91% of genera within the ecologically diverse palm family (Arecaceae). We then generated genomic repeat profiles for 141 palm species, and analysed repeats using phylogenetically-informed linear models to explore relationships between repeat dynamics and environmental factors. We show that palm genome size and repeat 'community' composition are best explained by aridity. Specifically, EnSpm CACTA repeats were more abundant in palm species from wetter environments, which generally had larger genomes (>2.15Gbp/1C), suggesting amplification. In contrast, Ty1-copia Angela elements were more abundant in drier environments. Our results suggest water stress inhibits the expansion of repeats through selection on upper genome size limits. However, Ty1-copia Angela elements, which may associate with stress-response genes, have amplified in arid-adapted palm species. Overall, we provide novel evidence of climate influencing the assembly of repeat 'communities'.

Intelligent wireless theranostic contact lens for close-loop electrical sensing and regulation of glaucoma

Engineered closed-loop devices that can wirelessly track intraocular pressure (IOP) and offer feedback-medicine administrations are highly desirable for glaucoma treatments, yet remain difficult to develop. Integrated theranostic systems based on contact lens still confront several challenges, including size limits, requirements of wireless operations, and cross-coupling between multiple functional modulus. Here, for the first time to our knowledge, an integrated wireless theranostic contact lens (WTCL) for in situ electrical sensing and on-demand drug delivery of glaucoma was developed. The WTCL utilized a highly compact circuitry and structural design, which enabled high-degreed integration of IOP sensing and electrically controlled delivery modulus on the curved and limited surface of contact lens. The wireless IOP sensing modulus could ultra-sensitively detect IOP fluctuations, due to the unique cantilever configuration design of LCR circuit with ultra-soft air dielectric film sandwiched between each capacitive sensing plate. The drug delivery modulus employed a highly efficient wireless power transfer circuit, to trigger delivery of anti-glaucoma drug into aqueous chamber via iontophoresis to enhance drug permeation across cornea. The specialized design of frequency separation enabled individual operations of different modules without cross-coupling. The minimally invasive, smart, wireless and closed-loop theranostic features endowed the WTCL as a highly promising system for glaucoma treatments.

Towards Fabrication of Planar Magnetoelectric Devices: Coil-Free Excitation of Ferromagnet-Piezoelectric Heterostructures

Magnetoelectric (ME) effects in composite ferromagnet-piezoelectric (FM/PE) heterostructures realize the mutual transformation of alternating magnetic and electric fields, and are used to create magnetic field sensors, actuators, inductors, gyrators, and transformers. The ME effect in composite structures is excited by an alternating magnetic field, which is created using volumetric electromagnetic coils. The coil increases the size, limits the operating frequencies, and complicates the manufacture of devices. In this work, we propose to excite the ME effect in composite heterostructures using a new coil-free excitation system, similar to a “magnetic capacitor”. The system consists of parallel electrodes integrated into the heterostructure, through which an alternating current flows. Modeling and measurements have shown that the excitation magnetic field is localized mainly between the electrodes of the magnetic capacitor and has a fairly uniform spatial distribution. Monolithic FM/PE heterostructures of various designs with FM layers of amorphous Metglas alloy or nickel-zinc ferrite and PE layers of lead zirconate titanate piezoceramic were fabricated and investigated. The magnitude of the ME effect in such structures is comparable to the magnitude of the ME effect in structures excited by volumetric coils. However, the low impedance of the coil-free excitation system makes it possible to increase the operating frequency, reducing the size of ME devices and the power consumption. The use of coil-free excitation opens up the possibility of creating planar ME devices, and accelerates their integration into modern electronics and microsystem technology.

Population structure and biological aspects of lobster (Panulirus spp.) of the Madura Strait landed in Situbondo of East Java, Indonesia

Lobster is an important economic fishery resource in domestic and international trade. The high economic value of lobster due to increasing market demand has led to its intensive exploitation. The enactment of specific regulations on lobster proves the urgency of its management. Madura Strait is one of the unique biogeographical sea regions of East Java. This research was conducted in January-March 2021 at Pasir Hitam Beach, Situbondo. The purpose of this study was to determine the species composition of lobsters, the frequency distribution and the growth form, and the sex ratio. The analysis applied is class distribution of length and weight classes, regression analysis, and chi-square. The lobster catches consist of 4 species, namely Scalloped spiny lobster (Panulirus homarus), Ornate spiny lobster (P. ornatus), Painted spiny lobster (P. versicolor), and Mud spiny lobster (P. polyphagus). P. homarus is the most dominant species. The frequency distribution of carapace length and weight of P. homarus, P. ornatus, and P. versicolor has met the minimum size limits rules. The length and weight relationship of P. Homarus and P. ornatus were negative allometric, while P. versicolor isometric. Lobster sex ratio is in a balanced condition.

Demographic shifts, inter-group contact, and environmental conditions drive language extinction and diversification

Humans currently collectively use thousands of languages1,2. The number of languages in a given region (i.e. language “richness”) varies widely3–7. Understanding the processes of diversification and homogenization that produce these patterns has been a fundamental aim of linguistics and anthropology. Empirical research to date has identified various social, environmental, geographic, and demographic factors associated with language richness3. However, our understanding of causal mechanisms and variation in their effects over space has been limited by prior analyses focusing on correlation and assuming stationarity3,8. Here we use process-based, spatially-explicit stochastic models to simulate the emergence, expansion, contraction, fragmentation, and extinction of language ranges. We varied combinations of parameter settings in these computer-simulated experiments to evaluate the extent to which different processes reproduce observed patterns of pre-colonial language richness in North America. We find that the majority of spatial variation in language richness can be explained by models in which environmental and social constraints determine population density, random shocks alter population sizes more frequently at higher population densities, and population shocks are more frequently negative than positive. Language diversification occurs when populations split after reaching size limits, and when ranges fragment due to population contractions following negative shocks or due to contact with other groups that are expanding following positive shocks. These findings support diverse theoretical perspectives arguing that language richness is shaped by environmental and social conditions, constraints on group sizes, outcomes of contact among groups, and shifting demographics driven by positive innovations, such as new subsistence strategies, or negative events, such as war or disease.

Integrated wireless theranostic contact lens for in situ electrical sensing and regulation of glaucoma

Engineered closed-loop devices that can wirelessly track intraocular pressure (IOP) and offer feedback-medicine administrations are highly desirable for glaucoma treatments, yet remain difficult to develop. Integrated theranostic systems based on contact lens still confront several challenges, including size limits, requirements of wireless operations, and cross-coupling between multiple functional modulus. Here, for the first time to our knowledge, an integrated wireless theranostic contact lens (WTCL) for in situ electrical sensing and on-demand drug delivery of glaucoma was developed. The WTCL utilized a highly compact circuitry and structural design, which enabled high-degreed integration of IOP sensing and electrically controlled delivery modulus on the curved and limited surface of contact lens. The wireless IOP sensing modulus could ultra-sensitively detect IOP fluctuations, due to the unique cantilever configuration design of LCR circuit with ultra-soft air dielectric film sandwiched between each capacitive sensing plate. The drug delivery modulus employed a highly efficient wireless power transfer circuit, to trigger delivery of anti-glaucoma drug into aqueous chamber via iontophoresis to enhance drug permeation across cornea. The specialized design of frequency separation enabled individual operations of different modules without cross-coupling. The noninvasive, smart, wireless and closed-loop theranostic features endowed the WTCL as a highly promising system for glaucoma treatments.

The first extinct species of <i>Acritus</i> LeConte, 1853 (Histeridae: Abraeinae) from Eocene Baltic amber: a microscopic beetle inclusion studied with X-ray micro-computed tomography

Acritus sutirca sp. nov. is described and illustrated from Eocene Baltic amber on the basis of one adult male specimen. As the first extinct member of the subfamily Abraeinae (Histeridae) and the smallest known fossil histerid specimen, this material was examined using a combination of light microscopy and X-ray micro-computed tomography (µCT). Internal features of the abdomen are well preserved, allowing us to study sclerotized parts of the aedeagus and illustrate these structures in detail. The current finding expands the range of known Histeridae diversity from the Eocene (48–34 Ma) “amber forests” of Europe. The absolute size limits and the probable average size for Baltic amber coleopteran inclusions are also briefly discussed (urn:lsid:zoobank.org:pub:A2B17479-8628-47C7-A8D4-3E0789BF088B).