1,280 research outputs found

    A Drosophila melanogaster H3.3 cDNA encodes a histone variant identical with the vertebrate H3.3

    Get PDF
    A cDNA encoding an H3.3 histone variant in Drosophila melanogaster predicts a protein with an amino acid (aa) sequence identical with that in vertebrates. The D. melanogaster H3.3 nucleotide (nt) sequence has diverged significantly from that of both the H3.3 gene of vertebrates and the H3.1 gene of D. melanogaster, largely through third nt changes in its codons. The perfect H3.3 aa sequence conservation between organisms as phylogenetically divergent as vertebrates and flies suggests that the H3.3 histone variant itself is an important structural component of chromatin, apart from the value of its replication-independent expression pattern. Keywords: Conserved proteins, amino acid sequence homologies, chromatin, bacteriophage λ library, invertebrat

    Effects of Pseudostreamer Boundary Dynamics on Heliospheric Field and Wind

    Get PDF
    Interchange reconnection has been proposed as a mechanism for the generation of the slow solar wind, and a key contributor to determining its characteristic qualities. In this paper we study the implications of interchange reconnection for the structure of the plasma and field in the heliosphere. We use the Adaptively Refined Magnetohydrodynamic Solver to simulate the coronal magnetic evolution in a coronal topology containing both a pseudostreamer and helmet streamer. We begin with a geometry containing a low-latitude coronal hole that is separated from the main polar coronal hole by a pseudostreamer. We drive the system by imposing rotating flows at the solar surface within and around the low-latitude coronal hole, which leads to a corrugation (at low altitudes) of the separatrix surfaces that separate open from closed magnetic flux. Interchange reconnection is induced both at the null points and separators of the pseudostreamer, and at the global helmet streamer. We demonstrate that a preferential occurrence of interchange reconnection in the "lanes" between our driving cells leads to a filamentary pattern of newly opened flux in the heliosphere. These flux bundles connect to but extend far from the separatrix-web (S-Web) arcs at the source surface. We propose that the pattern of granular and supergranular flows on the photosphere should leave an observable imprint in the heliosphere

    North Carolina Pharmacists’ Support for Hormonal Contraception Prescription Status Change

    Get PDF
    Background Pharmacist-prescribed hormonal contraception (HC) may offer additional avenues of access for patients; however, it is unknown whether pharmacists would support over-the-counter access to contraception over pharmacist-prescribed models. Objective The objective of this study was to understand how North Carolina (NC) pharmacists believed HC should be classified and how pharmacist and pharmacy characteristics were associated with those beliefs. Methods This study was a secondary analysis of a cross-sectional, anonymous, online survey completed by 587 licensed NC pharmacists. The primary outcome of interest was how pharmacists believed HC should be classified: prescription-only, pharmacist-prescribed, behind-the-counter, or over-the-counter. Multinomial bivariate and multivariable regression analyses were conducted to describe the association between pharmacist and pharmacy characteristics with the outcomes of interest through odds ratios and adjusted odds ratios, respectively. Chi-square tests were used to examine the association of geographic location with distribution of attitudes toward HC classification. Results Fifty-one percent of NC pharmacists supported classification of HC as pharmacist-prescribed, while 23% supported non-prescription (behind- or over-the-counter) classification. Controlling for pharmacist demographics and pharmacy characteristics, completing residency training was significantly associated with supporting pharmacist-prescribed vs prescription-only classification (adjusted odds ratio (aOR) = 2.55, P = .02). Pharmacists had higher odds of supporting pharmacist-prescribed vs prescription-only HC if they agreed that they were well trained to do so (aOR = 3.14, P < .01). Distribution of attitudes about classification of HC did not significantly differ by geographic location (P = .14). Conclusions Most NC pharmacists support deviating from the current prescription-only classification of HC, with more support for pharmacist-prescribed classification. Continuing education programs should focus on training pharmacists to feel more confident prescribing HC

    Collecting biological material from palliative care patients in the last weeks of life: a feasibility study

    Get PDF
    Objective To assess the feasibility of prospectively collecting biological samples (urine) from palliative care patients in the last weeks of life. Setting A 30-bedded specialist hospice in the North West of England. Participants Participants were adults with a diagnosis of advanced disease and able to provide written informed consent. Method Potential participants were identified by a senior clinician over a 12-week period in 2014. They were then approached by a researcher and invited to participate according to a developed recruitment protocol. Outcomes Feasibility targets included a recruitment rate of 50%, with successful collection of samples from 80% who consented. Results A total of 58 patients were approached and 33 consented (57% recruitment rate). Twenty-five patients (43%) were unable to participate or declined; 10 (17%) became unwell, too fatigued, lost capacity, died or were discharged home; and 15 (26%) refused, usually these patients had distressing pain, low mood or profound fatigue. From the 33 recruited, 20 participants provided 128 separate urine samples, 12 participants did not meet the inclusion criteria at the time of consent and 1 participant was unable to provide a sample. The criterion for a urinary catheter was removed for the latter 6 weeks. The collection rate during the first 6 weeks was 29% and 93% for the latter 6 weeks. Seven people died while the study was ongoing, and another 4 participants died in the following 4 weeks. Conclusions It is possible to recruit and collect multiple biological samples over time from palliative care patients in the last weeks and days of life even if they have lost capacity. Research into the biological changes at the end of life could develop a greater understanding of the biology of the dying process. This may lead to improved prognostication and care of patients towards the end of life

    Prediction of irradiation spectrum effects in pyrochlores

    Get PDF
    The formation energy of cation antisites in pyrochlores (A2B2O7) has been correlated with the susceptibility to amorphize under irradiation, and thus, density functional theory calculations of antisite energetics can provide insights into the radiation tolerance of pyrochlores. Here, we show that the formation energy of antisite pairs in titanate pyrochlores, as opposed to other families of pyrochlores (B = Zr, Hf, or Sn), exhibits a strong dependence on the separation distance between the antisites. Classical molecular dynamics simulations of collision cascades in Er2Ti2O7 show that the average separation of antisite pairs is a function of the primary knock-on atom energy that creates the collision cascades. Together, these results suggest that the radiation tolerance of titanate pyrochlores may be sensitive to the irradiation conditions and might be controllable via the appropriate selection of ion beam parameters

    The Imprint of Intermittent Interchange Reconnection on the Solar Wind

    Get PDF
    The solar wind is known to be highly structured in space and time. Observations from Parker Solar Probe have revealed an abundance of so-called magnetic switchbacks within the near-Sun solar wind. In this Letter, we use a high-resolution, adaptive-mesh, magnetohydrodynamics simulation to explore the disturbances launched into the solar wind by intermittent/bursty interchange reconnection and how they may be related to magnetic switchbacks. We find that repeated ejection of plasmoid flux ropes into the solar wind produces a curtain of propagating and interacting torsional Alfvénic waves. We demonstrate that this curtain forms when plasmoid flux ropes dynamically realign with the radial field as they are ejected from the current layer and that this is a robust effect of the 3D geometry of the interchange reconnection region. Simulated flythroughs of this curtain in the low corona reveal an Alfvénic patch that closely resembles observations of switchback patches, but with relatively small magnetic field deflections. Therefore, we suggest that switchbacks could be the solar wind imprint of intermittent interchange reconnection in the corona, provided an in situ process subsequently amplifies the disturbances to generate the large deflections or reversals of radial field that are typically observed. That is to say, our results indicate that a combination of low-coronal and inner-heliospheric mechanisms may be required to explain switchback observations

    Information-Geometric Indicators of Chaos in Gaussian Models on Statistical Manifolds of Negative Ricci Curvature

    Full text link
    A new information-geometric approach to chaotic dynamics on curved statistical manifolds based on Entropic Dynamics (ED) is proposed. It is shown that the hyperbolicity of a non-maximally symmetric 6N-dimensional statistical manifold M_{s} underlying an ED Gaussian model describing an arbitrary system of 3N degrees of freedom leads to linear information-geometric entropy growth and to exponential divergence of the Jacobi vector field intensity, quantum and classical features of chaos respectively.Comment: 8 pages, final version accepted for publicatio
    • 

    corecore