Karyotype depends on sperm head morphology in some amniote groups.

The karyotype of an organism is the set of gross features that characterize the way the genome is packaged into separate chromosomes. It has been known for decades that different taxonomic groups often have distinct karyotypic features, but whether selective forces act to maintain these differences over evolutionary timescales is an open question. In this paper we analyze a database of karyotype features and sperm head morphology in 103 mammal species with spatulate sperm heads and 90 sauropsid species (birds and non-avian reptiles) with vermiform heads. We find that mammal species with a larger head area have more chromosomes, while sauropsid species with longer heads have a wider range of chromosome lengths. These results remain significant after controlling for genome size, so sperm head morphology is the relevant variable. This suggest that post-copulatory sexual selection, by acting on sperm head shape, can influence genome architecture.

Establishing Core Symptoms of Acute Serotonin Reuptake Inhibitor Withdrawal: Results from an International Survey of Online Peer-Support Communities.

BACKGROUND: Serotonin reuptake inhibitor (SRI) antidepressants are commonly associated with withdrawal reactions. The Discontinuation Emergent Signs and Symptoms (DESS) checklist has been considered the gold standard research and screening tool for SRI withdrawal but has several limitations, including its length, lack of specificity, and omission of baseline symptom and symptom severity scores, making it impractical for use in clinical or research settings. We investigated the prevalence and severity of common SRI withdrawal symptoms to determine whether a very small subset of symptoms can capture most occurrences of SRI withdrawal. METHODS: We surveyed 344 members of online peer-support communities aged 18-65, reporting withdrawal symptoms after chronic SRI treatment. The severity of nine common withdrawal symptoms was evaluated at baseline and during the withdrawal period. RESULTS: Dizziness, brain zaps, irritability/agitation, and anxiety/nervousness demonstrated the largest increase in severity during withdrawal relative to baseline. Nearly all (97.7%) of the 344 subjects and all (100%) 153 subjects with relatively low baseline symptom scores (total<5) reported a worsening of one of these four symptoms. The presence of a baseline anxiety disorder did not affect rates of withdrawal-emergent anxiety/nervousness. CONCLUSION: Nearly all surveyed subjects reported worsening either of dizziness, brain zaps, irritability/agitation, or anxiety/nervousness in acute withdrawal. A screening test incorporating these four core symptoms may be sufficiently sensitive to rule out SRI withdrawal and may be valuable in clinical and research settings. Incorporating withdrawal symptom severity may further enhance specificity.

Carbonyl hypoiodites from pivalic and trimesic acid and their silver(I) intermediates.

The first tris(O-I-N) carbonyl hypoiodites have been synthesised based on trimesic acid and pyridine or 4-methylpyridine, with their structures definitively confirmed by single crystal X-ray diffraction (SCXRD). The more soluble carbonyl hypoiodites based on pivalic acid have also been studied via NMR, SCXRD, and computational analyses, enabling the study of the direct silver(I) precursor and intermediates of the resulting carbonyl hypoiodites generated using a range of substituted pyridines.

Accumulation of the gaseous hormone ethylene helps roots sense compact soil.

Soil compaction, in which soil grains are pressed together leaving less pore space for air and water, is a persistent problem in mechanized agriculture. Most plant roots fail to penetrate soil if it is too dense. One might assume that they are physically unable to penetrate the compact soil. However, new research demonstrates a more complex mechanism that requires the build-up of the volatile plant hormone ethylene in the rhizosphere1. Ethylene itself can arrest growth and, in compact soil, it is present in higher concentrations near roots due to its reduced ability to diffuse. Roots that lack the ethylene response pathway grow better through compact soil, demonstrating that it is physically possible to do so. The work suggests new levers for crop improvement in increasingly degraded soils.

Oxygen uptake rates have contrasting responses to temperature in the root meristem and elongation zone.

Growing at either 15 or 25°C, roots of Arabidopsis thaliana, Columbia accession, produce cells at the same rate and have growth zones of the same length. To determine whether this constancy is related to energetics, we measured oxygen uptake by means of a vibrating oxygen-selective electrode. Concomitantly, the spatial distribution of elongation was measured kinematically, delineating meristem and elongation zone. All seedlings were germinated, grown, and measured at a given temperature (15 or 25°C). Columbia was compared to lines where cell production rate roughly doubles between 15 and 25°C: Landsberg and two Columbia mutants, er-105 and ahk3-3. For all genotypes and temperatures, oxygen uptake rate at any position was highest at the root cap, where mitochondrial density was maximal, based on the fluorescence of a reporter. Uptake rate declined through the meristem to plateau within the elongation zone. For oxygen uptake rate integrated over a zone, the meristem had steady-state Q10 values ranging from 0.7 to 2.1; by contrast, the elongation zone had values ranging from 2.6 to 3.3, implying that this zone exerts a greater respiratory demand. These results highlight a substantial energy consumption by the root cap, perhaps helpful for maintaining hypoxia in stem cells, and suggest that rapid elongation is metabolically more costly than is cell division.

Contextual dimensions of moral injury: An interdisciplinary review.

The concept of moral injury, referring to the psychological impact of having one's moral expectations and beliefs violated, is gaining a firm place in research on military trauma. Yet, although moral injury has the recognized potential to extend the understanding of trauma beyond the individualizing and pathologizing focus of the clinical realm, most studies nevertheless focus on clinical assessment, diagnosis and treatment. This review aims to contribute to a better understanding of contextual dimensions of moral injury. To this end, it complements current theory on moral injury with a systematic review of literature relevant to contextual factors in moral injury. It draws together insights from psychology, philosophy, theology and social sciences into spiritual/existential, organizational, political and societal dimensions of moral injury. Thus an interdisciplinary theoretical foundation is created for context-sensitive research and interventions.

Accidentally Asymmetric Dark Matter.

We study the effect of a first-order phase transition in a confining SU(N) dark sector with heavy dark quarks. The baryons of this sector are the dark matter candidates. During the confinement phase transition the heavy quarks are trapped inside isolated, contracting pockets of the deconfined phase, giving rise to a second stage of annihilation that dramatically suppresses the dark quark abundance. The surviving abundance is determined by the local accidental asymmetry in each pocket. The correct dark matter abundance is obtained for O(1-100) PeV dark quarks, above the usual unitarity bound.

Dihypoiodites stabilised by 4-ethylpyridine through O-I-N halogen bonds.

Four bis(O-I-N) compounds have been synthesised from various dihypoiodites and 4-ethylpyridine. The compounds were characterised in both the solution and solid states by NMR spectroscopy (1H, 15N), X-ray diffraction, and computational calculations.

Scaling Laws for Mitotic Chromosomes.

During mitosis in higher eukaryotes, each chromosome condenses into a pair of rod-shaped chromatids. This process is co-regulated by the activity of several gene families, and the underlying biophysics remains poorly understood. To better understand the factors regulating chromosome condensation, we compiled a database of mitotic chromosome size and DNA content from the tables and figures of >200 published papers. A comparison across vertebrate species shows that chromosome width, length and volume scale with DNA content to the powers ∼1/4, ∼1/2, and ∼1, respectively. Angiosperms (flowering plants) show a similar length scaling, so this result is not specific to vertebrates. Chromosome shape and size thus satisfy two conditions: (1) DNA content per unit volume is approximately constant and (2) the cross-sectional area increases proportionately with chromosome length. Since viscous drag forces during chromosome movement are expected to scale with length, we hypothesize that the cross-section increase is necessary to limit the occurrence of large chromosome elongations that could slow or stall mitosis. Lastly, we note that individual vertebrate karyotypes typically exhibit a wider range of chromosome lengths as compared with angiosperms.

Heavy Thermal Dark Matter from a New Collision Mechanism.

We propose a new thermal freeze-out mechanism that results in dark matter masses exceeding the unitarity bound by many orders of magnitude, without violating perturbative unitarity or modifying the standard cosmology. The process determining the relic abundance is χζ^{†}→ζζ, where χ is the dark matter candidate. For m_{ζ}

Development of an online map of safe gun storage sites in Maryland for suicide prevention.

Reducing access to lethal means of self-harm is a cornerstone of suicide prevention, and temporary, voluntary gun storage outside the home is one recommended approach. With the goal of facilitating access to gun storage outside the home in Maryland, we developed an online map of gun shops and law enforcement agencies willing to offer temporary, voluntary gun storage on a case-by-case basis. This project was modelled off of prior work by the Colorado Firearm Safety Coalition. As of July 2020, 32 gun shops and 3 law enforcement agencies agreed to be listed on our map. Others were hesitant to participate due to perceived legal and logistical barriers to temporary firearm storage. We demonstrate the feasibility of creating an online map that lists organisations offering temporary gun storage in Maryland. This brief report details our process, barriers encountered, and future considerations to improve access to offsite gun storage options.

The accuracy vs. coverage trade-off in patient-facing diagnosis models.

A third of adults in America use the Internet to diagnose medical concerns, and online symptom checkers are increasingly part of this process. These tools are powered by diagnosis models similar to clinical decision support systems, with the primary difference being the coverage of symptoms and diagnoses. To be useful to patients and physicians, these models must have high accuracy while covering a meaningful space of symptoms and diagnoses. To the best of our knowledge, this paper is the first in studying the trade-off between the coverage of the model and its performance for diagnosis. To this end, we learn diagnosis models with different coverage from EHR data. We find a 1% drop in top-3 accuracy for every 10 diseases added to the coverage. We also observe that complexity for these models does not affect performance, with linear models performing as well as neural networks.

Flowering plant immune repertoires expand under mycorrhizal symbiosis.

Immune perception in flowering plants is mediated by a repertoire of cytoplasmic and cell-surface receptors that detect invading microbes and their effects on cells. Here, we show that several large families of immune receptors exhibit size variations related to a plant's competence to host symbiotic root fungi (mycorrhiza). Plants that do not participate in mycorrhizal associations have significantly smaller immune repertoires, while the most promiscuous symbiotic hosts (ectomycorrhizal plant species) have significantly larger immune repertoires. By contrast, we find no significant increase in immune repertoire size among legumes competent to form a symbiosis with nitrogen-fixing bacteria (rhizobia). To explain these observations, we hypothesize that plant immune repertoire size expands with symbiote species diversity.

Energy-Based Tissue Fusion for Sutureless Closure: Applications, Mechanisms, and Potential for Functional Recovery.

As minimally invasive surgical techniques progress, the demand for efficient, reliable methods for vascular ligation and tissue closure becomes pronounced. The surgical advantages of energy-based vessel sealing exceed those of traditional, compression-based ligatures in procedures sensitive to duration, foreign bodies, and recovery time alike. Although the use of energy-based devices to seal or transect vasculature and connective tissue bundles is widespread, the breadth of heating strategies and energy dosimetry used across devices underscores an uncertainty as to the molecular nature of the sealing mechanism and induced tissue effect. Furthermore, energy-based techniques exhibit promise for the closure and functional repair of soft and connective tissues in the nervous, enteral, and dermal tissue domains. A constitutive theory of molecular bonding forces that arise in response to supraphysiological temperatures is required in order to optimize and progress the use of energy-based tissue fusion. While rapid tissue bonding has been suggested to arise from dehydration, dipole interactions, molecular cross-links, or the coagulation of cellular proteins, long-term functional tissue repair across fusion boundaries requires that the reaction to thermal damage be tailored to catalyze the onset of biological healing and remodeling. In this review, we compile and contrast findings from published thermal fusion research in an effort to encourage a molecular approach to characterization of the prevalent and promising energy-based tissue bond.