Comparison of prenatal and postnatal ontogeny: cranial allometry in the African striped mouse (Rhabdomys pumilio)

The relationship between prenatal and postnatal ontogenetic allometry is poorly known, and empirical studies documenting prenatal allometry are few, precluding an understanding of changes in growth patterns during life history and their relation to proximal, physiological, and ultimate evolutionary variables. In this study I compare prenatal and postnatal ontogenetic allometry of the cranium in a cleared and stained developmental series of the African striped mouse (Rhabdomys pumilio). Eighteen cranial measurements, reflecting the dimensions of individual elements, were analyzed using bivariate and multivariate estimates of allometry and methods of matrix comparison. Prenatal allometry is characterized in R. pumilio by a relative rapid lengthening of cranial elements, particularly the frontal, parietal, basisphenoid, premaxilla, and palatine, as evidenced by larger bivariate allometric coefficients (>30% increase) and, across all variables measured, a greater proportion of cranial elements growing with a positive allometry than in the postnatal period. Growth dynamics are found to shift for measurements of several elements including the parietal, frontal, and palatine, indicating a nonlinearity of ontogenetic allometry with respect to birth; similar shifts have been found between prenatal and postnatal growth for some regions of the human cranium. Application of common principal component analyses, a generalized extension of principal component analysis, revealed that the prenatal and postnatal matrices shared a highly similar structure, further quantified by high correlations (>0.78) using the random skewers method of matrix comparison. These results indicate a close correspondence between morphology-based variance structures over the course of ontogeny in R. pumili

Diversity and evolution of femoral variation in Ctenohystrica

Despite possessing a rather generalised postcranial skeleton, rodents are on average capable of a wide variety of locomotory behaviours, such as swimming, digging and climbing (Nowak, 1999). Particularly, rodents belonging to Ctenohystrica (sensu Huchon et al., 2002, and Fabre et al., 2012: Ctenodactylidae, Diatomyidae and Hystricognathi) display a diversity of locomotory styles and encompass a large range in body mass from approximately 50 g for the naked mole-rat Heterocephalus glaber to around 60 kg for the largest living rodent, the capybara Hydrochoerus hydrochaeris, consequently filling many different ecological niches (e.g. MacDonald, 2009; Wilson and Sánchez-Villagra, 2009, 2010). Moreover, this diversity is greatly expanded by the inclusion of giant extinct members such as Phoberomys, Arazamys and Josephoartigasia that reached body masses at least seven or eight times that of the capybara (Sánchez-Villagra et al., 2003; Rinderknecht and Blanco, 2008; Rinderknecht and Bostelmann, 2011). The adaptive diversity that characterises the evolution of Ctenohystrica, and particularly the Caviomorpha, a group that dispersed from Africa to colonise South America (Poux et al., 2006; Rowe et al., 2010) and evolved on that continent during a period of splendid isolation in the Cenozoic, has been the subject of numerous morpho-functional and evolutionary studies (e.g. Verzi et al., 2010; Wilson et al., 2010; Álvarez et al., 2011a, b; Hautier et al., 2011, 2012; Cox et al., 2012; Geiger et al., 2013; Wilson, 2013). The interplay between form and function has been studied in the postcranial skeleton of a number of mammals (e.g. Kappelman, 19; Anemone, 1990;White, 1993; Vizcaíno and Milne, 2002; Kley and Kearney, 2007; Meachen-Samuels, 2010), and studies of Ctenohystrica have, for example, examined individual bones (e.g. Seckel and Janis, 2008; Morgan, 2009; Steiner-Souza et al., 2010; Elissamburu and De Santis, 2011), long bones (Biknevicius, 1993; Elissamburu and Vizcaino, 2004; Samuels and Van Valkenburgh, 2008; Morgan and Álvarez, 2013) and the autopodial skeleton (e.g. Weisbecker and Schmid, 2007; Morgan and Verzi, 2011). These studies have used morphological traits, described as ratios or quantified using biomechanical indices or geometric morphometric descriptors of shape, to identify functional specialisations and instances of adaptive convergence underpinned by shared function and/or ecology

Quantum entanglement between electronic and vibrational degrees of freedom in molecules

We consider the quantum entanglement of the electronic and vibrational degrees of freedom in molecules with a tendency towards double welled potentials using model coupled harmonic diabatic potential-energy surfaces. The von Neumann entropy of the reduced density matrix is used to quantify the electron-vibration entanglement for the lowest two vibronic wavefunctions in such a bipartite system. Significant entanglement is found only in the region in which the ground vibronic state contains a density profile that is bimodal (i.e., contains two separate local minima). However, in this region two distinct types of entanglement are found: (1) entanglement that arises purely from the degeneracy of energy levels in the two potential wells and which is destroyed by slight asymmetry, and (2) entanglement that involves strongly interacting states in each well that is relatively insensitive to asymmetry. These two distinct regions are termed fragile degeneracy-induced entanglement and persistent entanglement, respectively. Six classic molecular systems describable by two diabatic states are considered: ammonia, benzene, semibullvalene, pyridine excited triplet states, the Creutz-Taube ion, and the radical cation of the "special pair" of chlorophylls involved in photosynthesis. These chemically diverse systems are all treated using the same general formalism and the nature of the entanglement that they embody is elucidated

Effect of a Patient-Centered Phone Call by a Clinical Officer at Time of HIV Testing on Linkage to Care in Rural Kenya.

In a randomized controlled trial, we tested whether a structured, patient-centered phone call from a clinical officer after HIV testing improved linkage to/re-engagement in HIV care. Among 130 HIV-positive persons, those randomized to the phone call were significantly more likely to link to care by 7 and 30 days (P = .04)

Genetic variation in the farnesoid X-receptor predicts Crohn’s disease severity in female patients

The farnesoid X receptor (FXR) is implicated in Crohn\u27s disease (CD) pathogenesis. It is unclear how genetic variation in FXR impacts CD severity versus genetic variation in nuclear receptors such as pregnane X receptor (PXR) and the multi-drug resistance protein 1 (MDR1, ABCB1). To evaluate FXR-1G \u3e T as a genomic biomarker of severity in CD and propose a plausible molecular mechanism. A retrospective study (n = 542) was conducted in a Canadian cohort of CD patients. Genotypic analysis (FXR-1G \u3e T, MDR1 3435C \u3e T and PXR -25385C \u3e T) as well as determination of the FXR downstream product, fibroblast growth factor (FGF) 19 was performed. Primary outcomes included risk and time to first CD-related surgery. The effect of estrogen on wild type and variant FXR activity was assessed in HepG2 cells. The FXR-1GT genotype was associated with the risk of (odds ratio, OR = 3.34, 95% CI = 1.58–7.05, p = 0.002) and earlier progression to surgery (hazard ratio, HR = 3.00, 95% CI = 1.86–4.83, p \u3c 0.0001) in CD. Female carriers of the FXR-1GT genotype had the greatest risk of surgery (OR = 14.87 95% CI = 4.22–52.38, p \u3c 0.0001) and early progression to surgery (HR = 6.28, 95% CI = 3.62–10.90, p \u3c 0.0001). Women carriers of FXR-1GT polymorphism had a three-fold lower FGF19 plasma concentration versus women with FXR-1GG genotype (p \u3c 0.0001). In HepG2 cells cotransfected with estrogen receptor (ER) and FXR, presence of estradiol further attenuated variant FXR activity. MDR1 and PXR genotypes were not associated with surgical risk. Unlike MDR1 and PXR, FXR-1GT genetic variation is associated with earlier and more frequent surgery in women with CD. This may be through ER-mediated attenuation of FXR activation

Community-Led Response to Address Economic Vulnerability due to COVID-19 with, for, and by Transgender Women of Color: A Qualitative Pilot Evaluation

PURPOSE: Intersectional stigma fuels inequities among transgender women of color, which have been exacerbated by coronavirus disease 2019 (COVID-19). This study evaluated a community-led emergency assistance program for transgender women of color. METHODS: We conducted a pilot program evaluation (n=8). RESULTS: Retention was 87.5% over the follow-up. Funds were primarily used for bills, food, and housing. Requesting and receiving funds was described as somewhat to extremely easy. Participants identified the need for economic empowerment components in future programming, specifically gender affirmation, skill-building for education and employment, and entrepreneurial opportunities. CONCLUSION: Findings highlight the need to invest in community-led strategies to address inequities experienced by transgender women of color

High sensitivity of summer temperatures to stratospheric sulfur loading from volcanoes in the Northern Hemisphere

This work was funded by an ERC (European Research Council) Marie Curie Career Integration Grant (CIG14-631752) and a Philip Leverhulme prize in Earth Sciences (PLP-2021-167) from the Leverhulme Trust awarded to A.B. WH is funded by a UKRI Future Leaders Fellowship (MR/S033505/1). M.S. acknowledges the support of the ERC under the European Union’s Horizon 2020 research and innovation programme (grant agreement 820047). H.M.I. and L.C. were both funded by IAPETUS and IAPETUS2 NERC Doctoral Training Partnership. The Tunu2013 and NEEM_2011_S1 ice cores were collected and analyzed for sulfur and other chemical species used to establish the ice core chronologies with funding from NSF grants 1204176 and 0909541 to J.R.M., respectively, and ice cores were sampled with funding from NSF grant 1340174.The 540s, 1450s, and 1600s represent three of the five coldest decades in the Common Era (CE). In each of these cases, the cause of these cold pulses has been attributed to large volcanic eruptions. However, the provenance of the eruption and magnitude of the volcanic forcing remains uncertain. Here, we use high-resolution sulfur isotopes in Greenland and Antarctic ice cores measured across these events to provide a means of improving sulfur loading estimates for these eruptions. In each case, the largest reconstructed tree-ring cooling is associated with an extratropical eruption, and the high-altitude stratospheric sulfate loading of these events is substantially smaller than previous estimates (by up to a factor of two). These results suggest an increased sensitivity of the reconstructed Northern Hemisphere summer temperature response to extratropical eruptions. This highlights the importance of climate feedbacks and processes that amplify and prolong the cooling signal from high latitudes, such as changes in sea ice extent and ocean heat content.Publisher PDFPeer reviewe

Skeletogenesis and sequence heterochrony in rodent evolution, with particular emphasis on the African striped mouse, <i>Rhabdomys pumilio</i> (Mammalia)

Data documenting skeletal development in rodents, the most species-rich ‘order’ of mammals, are at present restricted to a few model species, a shortcoming that hinders exploration of the morphological and ecological diversification of the group. In this study we provide the most comprehensive sampling of rodent ossification sequences to date, with the aim of exploring whether heterochrony is ubiquitous in rodent evolution at the onset of skeletal formation. The onset of ossification in 17 cranial elements and 24 postcranial elements was examined for eight muroid and caviomorph rodent species. New data are provided for two non-model species. For one of these, the African striped mouse, Rhabdomys pumilio, sampling was extended by studying 53 autopodial elements and examining intraspecific variation. The Parsimov method of studying sequence heterochrony was used to explore the role that changes in developmental timing play in early skeletal formation. Few heterochronies were found to diagnose the muroid and caviomorph clades, suggesting conserved patterning in skeletal development. Mechanisms leading to the generation of the wide range of morphological diversity encapsulated within Rodentia may be restricted to later periods in development than those studied in this work. Documentation of skeletogenesis in Rhabdomys indicates that intraspecifc variation in ossification sequence pattern is present, though not extensive. Our study suggests that sequence heterochrony is neither pivotal nor prevalent during early skeletal formation in rodents.Facultad de Ciencias Naturales y Muse

Validation of Diffuse Correlation Spectroscopic Measurement of Cerebral Blood Flow Using Phase-Encoded Velocity Mapping Magnetic Resonance Imaging

Diffuse correlation spectroscopy (DCS) is a novel optical technique that appears to be an excellent tool for assessing cerebral blood flow in a continuous and non-invasive manner at the bedside. We present new clinical validation of the DCS methodology by demonstrating strong agreement between DCS indices of relative cerebral blood flow and indices based on phase-encoded velocity mapping magnetic resonance imaging (VENC MRI) of relative blood flow in the jugular veins and superior vena cava. Data were acquired from 46 children with single ventricle cardiac lesions during a hypercapnia intervention. Significant increases in cerebral blood flow, measured both by DCS and by VENC MRI, as well as significant increases in oxyhemoglobin concentration, and total hemoglobin concentration, were observed during hypercapnia. Comparison of blood flow changes measured by VENC MRI in the jugular veins and by DCS revealed a strong linear relationship, R = 0.88, p \u3c 0.001, slope = 0.91 ± 0.07. Similar correlations were observed between DCS and VENC MRI in the superior vena cava, R = 0.77, slope = 0.99 ± 0.12, p \u3c 0.001. The relationship between VENC MRI in the aorta and DCS, a negative control, was weakly correlated, R = 0.46, slope = 1.77 ± 0.45, p \u3c 0.001