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

Adding maps (GPS) to accelerometry data to improve study participants recall of physical activity: a methodological advance in physical activity research

pre-printObjective Obtaining the ‘when, where and why' of healthy bouts of moderate-to-vigorous physical activity (MVPA) provides insights into natural PA. Design In Salt Lake City, Utah, adults wore accelerometer and Global Positioning System (GPS) loggers for a week in a cross-sectional study to establish baseline travel and activity patterns near a planned Complete Street intervention involving a new rail line, new sidewalks and a bike path. Results At the end of the week, research assistants met with the 918 participants who had at least three 10 h days of good accelerometer readings. Accelerometer and GPS data were uploaded and integrated within a custom application, and participants were provided with maps and time information for past MVPA bouts of ≥3 min to help them recall bout details. Participants said that ‘getting someplace' was, on average, a more important motivation for their bouts than leisure or exercise. A series of recall tests showed that participants recalled most bouts they were asked about, regardless of the duration of the bout, suggesting that participant perceptions of their shorter lifestyle bouts can be studied with this methodology. Visual prompting with a map depicting where each bout took place yielded more accurate recall than prompting with time cues alone. Conclusions These techniques provide a novel way to understand participant memories of the context and subjective assessments associated with healthy bouts of PA. Prompts with time-stamped maps that illustrate places of MVPA offer an effective method to improve understanding of activity and its supportive sociophysical context

On the Chopping Block: Examining the Fairness of Observational Data of Teacher Effectiveness

Since the No Child Left Behind legislation, the assessment of teacher effectiveness (TE) for accountability purposes has been at the forefront of educational policy. Prominent among both already-existing and newly developed measures is the Classroom Assessment Scoring System (CLASS; Pianta, La Paro, & Hamre, 2008). The CLASS is used currently in over 40 states across the country (Teachstone, 2013; Office of Head Start, 2014) to make high-stakes decisions for teachers, including compensation, promotion, and termination. For this reason, it is important that measures like the CLASS are evaluated by research. Our research hypothesizes that if measures like the CLASS can be reliably used for high-stakes outcomes, then scores for individual teachers should remain stable over time, and particularly so within units of thematically related lessons. We used a single-subject design, reflective of the real-world uses of TE scores, to assess score stability for two kindergarten teachers purposively selected from a larger database. Stability ranges were created around mean scores and then visually examined. Significant variability was found between lessons for both teachers, particularly in the instructional support domain of the CLASS. We conclude that single observations are likely not sufficient to reliably evaluate teachers’ instructional effectiveness. Further research should investigate: (1) if similar variability is found with a larger number of teachers when observed for longer periods of time; (2) if this instability is found when using other TE measures; (3) the factors that contribute to observed instability; and (4) the number of teacher observations needed to obtain accurate views of teachers’ effectiveness patterns

Infrared Variability of Two Dusty White Dwarfs

The most heavily polluted white dwarfs often show excess infrared radiation from circumstellar dust disks, which are modeled as a result of tidal disruption of extrasolar minor planets. Interaction of dust, gas, and disintegrating objects can all contribute to the dynamical evolution of these dust disks. Here, we report on two infrared variable dusty white dwarfs, SDSS J1228+1040 and G29-38. For SDSS J1228+1040, compared to the first measurements in 2007, the IRAC [3.6] and [4.5] fluxes decreased by 20% by 2014 to a level also seen in the recent 2018 observations. For G29-38, the infrared flux of the 10 $\mu$m silicate emission feature became 10% stronger between 2004 and 2007, We explore several scenarios that could account for these changes, including tidal disruption events, perturbation from a companion, and runaway accretion. No satisfactory causes are found for the flux drop in SDSS J1228+1040 due to the limited time coverage. Continuous tidal disruption of small planetesimals could increase the mass of small grains and concurrently change the strength of the 10 $\mu$m feature of G29-38. Dust disks around white dwarfs are actively evolving and we speculate that there could be different mechanisms responsible for the temporal changes of these disks.Comment: ApJ, in pres

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

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)

Pulsed ultraviolet light decontamination of artificially-generated microbiological aerosols

Airborne transmission of infectious organisms is a major public health concern, particularly within healthcare and communal public environments. Methods of environmental decontamination utilising pulsed ultraviolet (UV) light are currently available, however it is important that germicidal efficacy against airborne contamination is established. This study demonstrates evidence of the dose-response kinetics of airborne bacterial contamination when exposed to pulsed UV-rich (PUV) light. Bacterial aerosols (Staphylococcus epidermidis) were generated using a 6-Jet Collison nebuliser, and introduced into a custom-designed aerosol chamber which enabled prolonged airborne suspension and circulation. Bacterial aerosols were exposed to short duration pulses (~20 µs) of UV-rich light emitted from a xenon-filled flashlamp. The lamp was operated using a 1 kV solid–state pulsed power source, with a pulse frequency of 1 Hz, and output energy of 20 J/pulse. Post-treatment, air samples were extracted from the chamber using a BioSampler liquid impinger, and the surviving fraction was enumerated using standard microbiological culture methods. Results demonstrate successful aerosol inactivation, with a 66.4% reduction achieved with only 10 pulses of UV-rich light (P=<0.0002). Inactivation using continuous UV light was also investigated in order to quantify the comparative efficacy of these antimicrobial light regions. In addition to determining the inactivation kinetics, the spectral outputs of the pulsed and continuous UV sources were captured and compared in order to assess their comparative UV-C content, and subsequently assess how this UV content relates to their germicidal efficiency. Overall, results provide evidence of the dose-response kinetics of bacterial aerosols to PUV-rich light. As with continuous UV light, safety restrictions limit its application to unoccupied environments, or within sealed enclosures such as air handling units, however the reduced treatment times with PUV provides operational advantages over continuous light treatment

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

Keeping an eye on decellularized corneas: a review of methods, characterization and applications

The worldwide limited availability of suitable corneal donor tissue has led to the development of alternatives, including keratoprostheses (Kpros) and tissue engineered (TE) constructs. Despite advances in bioscaffold design, there is yet to be a corneal equivalent that effectively mimics both the native tissue ultrastructure and biomechanical properties. Human decellularized corneas (DCs) could offer a safe, sustainable source of corneal tissue, increasing the donor pool and potentially reducing the risk of immune rejection after corneal graft surgery. Appropriate, human-specific, decellularization techniques and high-resolution, non-destructive analysis systems are required to ensure reproducible outputs can be achieved. If robust treatment and characterization processes can be developed, DCs could offer a supplement to the donor corneal pool, alongside superior cell culture systems for pharmacology, toxicology and drug discovery studies

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