Structural racism in the USA has roots that extend deep into healthcare and medical research, and it remains a key driver of illness and early death for Black, Indigenous, People of Color (BIPOC). Furthermore, the persistence of racism within academic medicine compels an interrogation of education and research within this context. In the spirit of this interrogation, this article highlights a unique model of community-engaged education that integrates cultural humility. As an individual and institutional stance, cultural humility denotes lifelong learning and self-critique, the mitigation of power imbalances, and accountability. The integration of cultural humility emphasizes that when space is created for BIPOC communities to lead the way, education regarding healthcare and research can be effectively reimagined. Demonstrating this effectiveness, six community partners led the development and implementation of a five-module Structural Racism in Healthcare and Research course. Using a cohort model approach, the pilot course enrolled 12 community members and 12 researchers. The curriculum covered topics such as history of racism in healthcare and research, and introduced participants to a cultural resilience framework. Evaluation results demonstrated a significant increase in participants’ knowledge and ability to identify and take action to address inequities related to racism in healthcare and research.

Models for traveling waves in multi-fluid plasmas give essential insight into fully nonlinear wave structures in plasmas, not readily available from either numerical simulations or from weakly nonlinear wave theories. We illustrate these ideas using one of the simplest models of an electron–proton multi-fluid plasma for the case where there is no magnetic field or a constant normal magnetic field present. We show that the traveling waves can be reduced to a single first-order differential equation governing the dynamics. We also show that the equations admit a multi-symplectic Hamiltonian formulation in which both the space and time variables can act as the evolution variable. An integral equation useful for calculating adiabatic, electrostatic solitary wave signatures for multi-fluid plasmas with arbitrary mass ratios is presented. The integral equation arises naturally from a fluid dynamics approach for a two fluid plasma, with a given mass ratio of the two species (e.g. the plasma could be an electron–proton or an electron–positron plasma). Besides its intrinsic interest, the integral equation solution provides a useful analytical test for numerical codes that include a proton–electron mass ratio as a fundamental constant, such as for particle in cell (PIC) codes. The integral equation is used to delineate the physical characteristics of ion acoustic traveling waves consisting of hot electron and cold proton fluids.

In this paper, high temperature (>1400°C) thermal oxidation has been applied, for the first time, to 4H-SiC PiN diodes with thick (110 μm) drift regions, for the purpose of increasing the carrier lifetime in the semiconductor. PiN diodes were fabricated using 4H-SiC material that had undergone thermal oxidation performed at 1400°C, 1500°C and 1600°C, then were electrically characterized. Forward current-voltage (I-V) measurements showed that thermally oxidized PiN diodes exhibited considerably improved electrical characteristics, with devices oxidized at 1500°C having a forward voltage drop (V F ) of 4.15 V and a differential on-resistance (R on,diff ) of 8.9 mΩ-cm2 at 100 A/cm2 and 25°C. Compared to typical control sample PiN diode characteristics, this equated to an improvement of 8% and 23% for V F and R on,diff , respectively. From analysis of the reverse recovery characteristics, the carrier lifetime of the PiN diodes oxidized at 1500°C was found to be 1.05 μs, which was an improvement of around 30% compared to the control sample PiN diodes.

Multi-dimensional Alfvén simple waves in magnetohydrodynamics (MHD) are investigated using Boillat's formalism. For simple wave solutions, all physical variables (the gas density, pressure, fluid velocity, entropy, and magnetic field induction in the MHD case) depend on a single phase function ϕ, which is a function of the space and time variables. The simple wave ansatz requires that the wave normal and the normal speed of the wave front depend only on the phase function ϕ. This leads to an implicit equation for the phase function and a generalization of the concept of a plane wave. We obtain examples of Alfvén simple waves, based on the right eigenvector solutions for the Alfvén mode. The Alfvén mode solutions have six integrals, namely that the entropy, density, magnetic pressure, and the group velocity (the sum of the Alfvén and fluid velocity) are constant throughout the wave. The eigenequations require that the rate of change of the magnetic induction B with ϕ throughout the wave is perpendicular to both the wave normal n and B. Methods to construct simple wave solutions based on specifying either a solution ansatz for n(ϕ) or B(ϕ) are developed.

In a 5-week study of 22 depressed patients treated with nortriptyline, significant changes in plasma levels, both elevated and reduced, were deliberately produced in the third and fourth weeks of each patient's treatment. Correlation of plasma nortriptyline levels and changes in the severity of depression, as measured by the Hamilton Depression Scale, showed no significant relationships. The implications of the study are discussed.

Ninety-eight samples of pig slurry from 54 farms were examined for the presence of salmonellas, porcine enteropathogenic strains of haemolytic Escherichia coli and mycobacteria. Salmonellas were isolated from 12 farms (22 %) and enteropathogenic E. coli from 13 farms (24%). Pathogenic mycobacteria were not isolated.

Salmonellas were isolated from 7 of 16 farms (44%) stocked with ‘minimal disease’ pigs compared with only 5 of 38 farms (13%) stocked with conventionally reared pigs. Conversely enteropathogenic coliforms were isolated from 3 of 16 farms (19%) stocked with ‘minimal disease’ pigs compared with 10 of 38 farms (26%) stocked with conventionally reared pigs.

A cDNA clone encoding a full length putative collagen has been isolated in a screen of a mixed stage Globodera pallida expression library. Comparison of the deduced amino acid sequence of this molecule with other collagens suggests it is a cuticular collagen and a member of the col-8 subfamily of collagen genes. Northern blots show the gene is expressed specifically in gravid, adult females of the parasite as compared to second (invasive) stage juveniles and virgin females. Preliminary immunocytochemical studies indicate this collagen is present in areas other than the cuticle; these findings and the potential functional role of this collagen are discussed.

A genomic library of Meloidogyne incognita Race 1 has been prepared in the bacteriophage λgt10 and screened for specific DNA sequences by hybridization with radio-isotope labelled total genomic DNA from a number of Meloidogyne species. One clone isolated (MR1#15), although not totally species specific, clearly showed preferential hybridization to M. incognita. Following subcloning and sequencing of the 255 bp insert, four stretches of the sequence corresponding to oligonucleotides of approximately equal length (~60 bp) were synthesized and examined for specificity. One of them, MR1#15.2, showed the necessary specificity to be used as a diagnostic tool.

It is well established that resource variability generated by spatial patchiness and turbulence is an importantinfluence on the growth and recruitment of planktonic fish larvae. Empirical data show fractal-like prey distributions, and simulationsindicate that scale-invariant foraging strategies may be optimal. Here we show how larval growth and recruitment in a turbulent environment canbe formulated as a hitting time problem for a jump-diffusion process. We present two theoretical results. Firstly, if jumps are of a fixed sizeand occur as a Poisson process (embedded within a drift-diffusion), recruitment is effectively described by a diffusion process alone.Secondly, in the absence of diffusion, and for “patchy” jumps (of negative binomial size with Pareto inter-arrivals), the encounter processbecomes superdiffusive. To synthesise these results we conduct a strategic simulation study where “patchy” jumps are embedded in adrift-diffusion process. We conclude that increasingly Lévy-like predator foraging strategies can have a significantly positive effect onrecruitment at the population level.

We report on the results of our monitoring program of SNR 1987A with the Chandra X-Ray Observatory. The high resolution images and the spectra from the latest Chandra data suggest that the blast wave has reached the dense inner ring on the western side of the SNR, as well as in the east. The observed soft X-ray flux is increasing more rapidly than ever, and the latest flux is four times brighter than three years ago.

Gilliland et al. (2000) have reported HST photometric observations of 34000 stars in the globular cluster 47 Tuc, showing an absence of close-in giant planets in that cluster relative to their frequency in the solar neighborhood. Here we describe the methods of time-series analysis that were used to search the 47 Tuc data for transits by giant extrasolar planets, and the means by which these methods were validated.

With sub-arcsecond angular resolution accompanied by fast time resolution and spatially resolved spectral capabilities, the Chandra X-ray Observatory provides a unique capability for the study of supernova remnants (SNRs) and pulsars. Though in its relative infancy, Chandra has already returned stunning images of SNRs which reveal the distribution of ejecta synthesized in the stellar explosions, the distinct properties of the forward and reverse shocks, and the presence of faint shells surrounding compact remnants. Pulsar observations have uncovered jet features as well as small-scaled structures in synchrotron nebulae. In this brief review we discuss results from early Chandra studies of pulsars and SNRs.

It is currently thought that New World monkeys, prosimians, and humans are the only primates to possess vomeronasal organs (VNOs) as adults. Recent studies of the human VNO suggest that previous investigations on Old World primates may have missed the VNO. We examined nasal septa from the chimpanzee (Pan troglodytes) grossly and histologically for comparison with nasal septa from humans, Old World monkeys (Macaca fascicularis, M. nemistrina) and prosimian primates (Microcebus murinus, Otolemur garnettii). Grossly, chimpanzees had depressions on the nasal septum similar to fossae reported anterior to the VNO openings in humans. Histologically, chimpanzees and humans had bilateral epithelial tubes which were above the superior margin of the paraseptal cartilages (vomeronasal cartilage homologue). The epithelial tubes had a homogeneous ciliated epithelium. These structures were thus positionally and structurally identical to the human VNO and unlike the well-developed prosimian VNOs which were surrounded by vomeronasal cartilage. Macaques had no structures which resembled the VNO of either the prosimians or humans. The results demonstrate that the VNO is present postnatally in the chimpanzee and is almost identical to the human VNO in its anatomical position and histological structure. This in turn suggests that the reported absence of the VNO in at least some adult Old World primates is artifactual, and that further study may provide evidence for its existence in other species.