Genomic landscape of early ecological speciation initiated by selection on nuptial color.

Ecological speciation is the evolution of reproductive isolation as a consequence of direct divergent natural selection or ecologically mediated divergent sexual selection. While the genomic signature of the former has been extensively studied in recent years, only few examples exist for genomic differentiation where environment-dependent sexual selection has played an important role. Here, we describe a very young (~90 years old) population of threespine sticklebacks exhibiting phenotypic and genomic differentiation between two habitats within the same pond. We show that differentiation among habitats is limited to male throat color and nest type, traits known to be subject to sexual selection. Divergence in these traits mirrors divergence in much older benthic and limnetic stickleback species pairs from North American Westcoast lakes, which also occur in sympatry but are strongly reproductively isolated from each other. We demonstrate that in our population, differences in throat color and breeding have been stable over a decade, but in contrast to North American benthic and limnetic stickleback species, these mating trait differences are not accompanied by divergence in morphology related to feeding, predator defense or swimming performance. Using genome-wide SNP data, we find multiple genomic islands with moderate differentiation spread across several chromosomes, whereas the rest of the genome is undifferentiated. The islands contain potential candidate genes involved in visual perception of color. Our results suggest that phenotypic and multi-chromosome genomic divergence of these morphs was driven by environment-dependent sexual selection, demonstrating incipient speciation after only a few decades of divergence in sympatry. This article is protected by copyright. All rights reserved

Socially Excluded Individuals Fail to Recruit Medial Prefrontal Cortex for Negative Social Scenes

Converging behavioral evidence suggests that people respond to experiences of social exclusion with both defensive and affiliative strategies, allowing them to avoid further distress while also encouraging re-establishment of positive social connections. However, there are unresolved questions regarding the cognitive mechanisms underlying people\u27s responses to social exclusion. Here, we sought to gain insight into these behavioral tendencies by using functional magnetic resonance imaging (fMRI) to examine the impact of social exclusion on neural responses to visual scenes that varied on dimensions of sociality and emotional valence. Compared to socially included participants, socially excluded participants failed to recruit dorsomedial prefrontal cortex (dmPFC), a brain region involved in mentalizing, for negative social scenes. Moreover, following social exclusion, dmPFC demonstrated a linear effect of valence, with greater activity to positive social scenes compared to negative social scenes. These results suggest that, following social exclusion, people display a preference for mentalizing about positive social information and tend to avoid negative aspects of their social world

Investigating the Morphological and Genetic Divergence of Arctic Char \u3ci\u3e(Salvelinus alpinus)\u3c/i\u3e Populations in Lakes of Arctic Alaska

Polymorphism facilitates coexistence of divergent morphs (e.g., phenotypes) of the same species by minimizing intraspecific competition, especially when resources are limiting. Arctic char (Salvelinus sp.) are a Holarctic fish often forming morphologically, and sometimes genetically, divergent morphs. In this study, we assessed the morphological and genetic diversity and divergence of 263 individuals from seven populations of arctic char with varying length-frequency distributions across two distinct groups of lakes in northern Alaska. Despite close geographic proximity, each lake group occurs on landscapes with different glacial ages and surface water connectivity, and thus was likely colonized by fishes at different times. Across lakes, a continuum of physical (e.g., lake area, maximum depth) and biological characteristics (e.g., primary productivity, fish density) exists, likely contributing to characteristics of present-day char populations. Although some lakes exhibit bimodal size distributions, using model-based clustering of morphometric traits corrected for allometry, we did not detect morphological differences within and across char populations. Genomic analyses using 15,934 SNPs obtained from genotyping by sequencing demonstrated differences among lake groups related to historical biogeography, but within lake groups and within individual lakes, genetic differentiation was not related to total body length. We used PERMANOVA to identify environmental and biological factors related to observed char size structure. Significant predictors included water transparency (i.e., a primary productivity proxy), char density (fish·ha-1), and lake group. Larger char occurred in lakes with greater primary production and lower char densities, suggesting less intraspecific competition and resource limitation. Thus, char populations in more productive and connected lakes may prove more stable to environmental changes, relative to food-limited and closed lakes, if lake productivity increases concomitantly. Our findings provide some of the first descriptions of genomic characteristics of char populations in arctic Alaska, and offer important consideration for the persistence of these populations for subsistence and conservation

Асинхронный электропривод экструдера полипропиленовой нити

В данной выпускной квалификационной работе рассматривается система экструдера линии TL – 60. Проведены исследования работы электропривода экструдера в динамических режимах работы. В основной части работы рассмотрены: объект автоматизации, техно-логический процесс, требования к электроприводу, функциональная схема системы экструдера, структурные схемы экструдера и регулируемого электропривода (РЭП). Расчетная часть включает в себя расчет параметров силовой цепи, характеристик системы векторного управления и тиристорного преобразователя, проверку области существования электромеханических характеристик привода, а также синтез структуры системы регулирования диаметра и их анализ.This qualification system is graduation extruder line TL-60. Studies of the work of the electric drive of the extruder in dynamic modes. In the main part of the work considered: Automation object, techno-logical process, drive requirements, functional scheme of the extruder, extruder structural schemes and controlled electric drive (CED). Estimated portion includes the calculation of parameters of the power circuit, vector control and system characteristics of the thyristor converter, check the field existence of electromechanical actuator characteristics, as well as the regulatory system structure synthesis and analysis of diameter

Prescription Stimulants in College and Medical Students: A Narrative Review of Misuse, Cognitive Impact, and Adverse Effects

Stimulants are effective in treating attention-deficit/hyperactivity disorder (ADHD). Psychiatrist Charles Bradley first made this discovery in 1937 when he found that children treated with amphetamines showed improvements in school performance and behavior. Between 1995 and 2008, stimulants to treat ADHD increased six-fold among American adults and adolescents at an annual rate of 6.5%. Stimulants without a prescription, known as nonmedical use or misuse, have also increased. The highest rates of nonmedical prescription drug misuse in the United States are seen most notably in young adults between 18 and 25 years, based on data from the Substance Abuse and Mental Health Services Administration in 2021. Aside from undergraduate students, nonmedical prescription stimulant use is prevalent among medical students worldwide. A recent literature review reported the utilization of stimulants without a prescription in 970 out of 11,029 medical students. The percentages of medical students across the country misusing stimulants varied from 5.2% to 47.4%. Academic enhancement, reported in 50% to 89% of college students with stimulant misuse, is the most common reason for nonmedical stimulant use. With the increasing use of stimulants among adolescents and adults, it is unclear what long-term outcomes will be since little data are available that describe differences in how side effects are experienced for prescribed and non-prescribed users. The present narrative review focuses on these adverse effects in this population and the reasonings behind misuse and nonmedical use

Current Status of Cord Blood Banking and Transplantation in the United States and Europe

Cord blood (CB) transplantation has expanded the ability of the transplantation community to meet the growing needs of their patients. Clinical data over the last decade show promising results in CB transplantation using blood from related as well as unrelated donors. Basic science continues to look for ways to expand the quality and quantity of CB. CB banks are now established around the world, with major efforts to standardize banking to facilitate regulation, collection, processing, and distribution as a way of providing the highest-quality CB for patient use. This review article discusses the current status of CB transplantation and banking in the United States and Europe

Alternative Options for Complex, Recurrent Pain States Using Cannabinoids, Psilocybin, and Ketamine: A Narrative Review of Clinical Evidence

With emerging information about the potential for morbidity and reduced life expectancy with long-term use of opioids, it is logical to evaluate nonopioid analgesic treatments to manage pain states. Combinations of drugs can provide additive and/or synergistic effects that can benefit the management of pain states. In this regard, tetrahydrocannabinol (THC) and cannabidiol (CBD) modulate nociceptive signals and have been studied for chronic pain treatment. Psilocybin, commonly known as magic mushrooms , works at the serotonin receptor, 5-HT. Psilocybin has been found in current studies to help with migraines since it has a tryptamine structure and works similarly to triptans. Psilocybin also has the potential for use in chronic pain treatment. However, the studies that have looked at alternative plant-based medications such as THC, CBD, and psilocybin have been small in terms of their sample size and may not consider the demographic or genetic differences in the population because of their small sample sizes. At present, it is unclear whether the effects reported in these studies translate to the general population or even are significant. In summary, additional studies are warranted to evaluate chronic pain management with alternative and combinations of medications in the treatment of chronic pain

Ancient hybridization fuels rapid cichlid fish adaptive radiations.

Understanding why some evolutionary lineages generate exceptionally high species diversity is an important goal in evolutionary biology. Haplochromine cichlid fishes of Africa's Lake Victoria region encompass >700 diverse species that all evolved in the last 150,000 years. How this 'Lake Victoria Region Superflock' could evolve on such rapid timescales is an enduring question. Here, we demonstrate that hybridization between two divergent lineages facilitated this process by providing genetic variation that subsequently became recombined and sorted into many new species. Notably, the hybridization event generated exceptional allelic variation at an opsin gene known to be involved in adaptation and speciation. More generally, differentiation between new species is accentuated around variants that were fixed differences between the parental lineages, and that now appear in many new combinations in the radiation species. We conclude that hybridization between divergent lineages, when coincident with ecological opportunity, may facilitate rapid and extensive adaptive radiation

Complete mitochondrial genomes and updated divergence time of the two freshwater clupeids endemic to Lake Tanganyika (Africa) suggest intralacustrine speciation

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