Bioethics education in residency helps trainees achieve many of the Accreditation Council for Graduate Medical Education milestones and gives them resources to respond to bioethical dilemmas. For this purpose, The Providence Center for Health Care Ethics has offered a robust clinical ethics rotation since 2000. The importance of bioethics for residents was highlighted as the COVID-19 pandemic raised significant bioethical concerns and moral distress for residents. This, combined with significant COVID-19-related practical stressors on residents led us to develop a virtual ethics rotation. A virtual rotation allowed residents flexibility as they were called to help respond to the unprecedented demands of a pandemic without compromising high quality education. This virtual rotation prioritized flexibility to support resident wellbeing and ethical analysis of resident experiences. This article describes how this rotation was able to serve residents without overstraining limited bandwidth, and address the loci of resident pandemic distress. As pandemic pressures lessened, The Providence Center for Health Care Ethics transitioned to a hybrid rotation which continues to prioritize resident wellbeing and analysis of ongoing stressors while incorporating in-person elements where they can improve learning. This article provides a description of the rotation in its final form and resident feedback on its effectiveness.

Nebraska is one of the top five corn-growing states in the United States, with the planting of corn on 3.5 to 4 million hectares annually. Harvest loss of corn results in volunteer corn interference in the crop grown in rotation. Estimating the extent of harvest loss and expected volunteer corn density is a key to planning an integrated volunteer corn management program. This study aimed to evaluate the harvest loss of corn and estimate the potential for volunteerism. Harvest loss samples were collected after corn harvest from a total of 47 fields in six counties, including 26 corn fields in 2020, and 21 fields in 2021, in south-central and southeastern Nebraska. An individual cornfield size was 16 to 64 ha. A total of 16 samples were collected from each field after corn harvest in 2020 and 2021. Harvest loss of corn was 1.5% and 0.7% of the average yield of 15,300 kg ha−1 in 2020 and 2021, respectively. Corn harvest loss was 191 and 80 kg ha−1 from dryland fields, and 206 and 114 kg ha−1 from irrigated fields in 2020 and 2021, respectively. An average kernel loss of 68 and 33 m−2 occurred in 2020 and 2021, respectively. The germination percentage of corn kernels collected from harvest loss was 51%, which implies that volunteer corn plants of 35 and 17 m−2 from 2020 and 2021, respectively, could be expected in successive years. A volunteer corn management plan is required, because if it is not controlled, this level of volunteer corn density can cause yield reduction depending on the crop grown in rotation.

Mercury is locked in an unusual 3:2 spin-orbit resonance and as such is expected to be in a state of equilibrium called Cassini state. In that state, the angle between the spin axis and orbit normal, called obliquity, remains almost constant while the spin axis remains almost in the plane, also called Cassini plane, defined by the normal to the Laplace plane and the normal to the orbital plane. The spin axis and the orbit normal precess together with a period of about 300 kyr. The orientation of the spin axis of Mercury has been estimated using different approaches: (i) Earth-based radar observations, (ii) Messenger images and altimeter data, and (iii) Messenger radio tracking data. The different estimates all tend to confirm that Mercury occupies the Cassini state. The observed obliquity is small and close to 2 arcmin. It indicates a normalized polar moment of inertia of about 0.34. This information, combined with the existence of a liquid iron core, as evidenced by the librations, allows to constrain the interior structure of Mercury. However, the different estimates of the orientation of the spin axis locate the spin axis somewhat behind or ahead of the Cassini plane, and it is difficult to reconcile and interpret them coherently in terms of detailed interior properties. We review recent models for the obliquity and spin orientation of Mercury, which include the effects of complex orbital dynamics, tidal deformations and associated dissipation, and internal couplings related to the presence of fluid and solid cores. We discuss some implications regarding the interpretations of the orientation estimates in term of interior properties.

This paper reviews our current knowledge about pulsating chemically peculiar (CP) stars. CP stars are slowly rotating upper main-sequence objects, efficiently employing diffusion in their atmospheres. They can be divided into magnetic and non-magnetic objects. Magnetic activity significantly influence their pulsational characteristics. Only a handful of magnetic, classical pulsating objects are now known. The only exceptions are about 70 rapidly oscillating Ap stars, which seem to be located within a very tight astrophysical parameter space. Still, many observational and theoretical efforts are needed to understand all important physical aspects and their interrelationships. The most important steps to reach these goals are reviewed.

In this short review we present the recent progresses in modelling fast rotating stars in two dimensions. We thus give a brief description of the features of the public domain code ESTER that can compute self-consistently the structure and the large-scale flows (differential rotation and meridional circulation) of an axisymmetric stellar model of a (fast) rotating early-type main sequence star. We illustrate these modelling with the recent results obtained on Altair, a nearby extremely fast rotator. We then discuss the various way mixing takes place in the stably stratified radiative envelope of early-type stars, and especially in massive ones where the radiative winds add a new source of large-scale flows, which are shown to be strongly anisotropic and very difficult to represent in one dimension.

We present results from 3D MHD simulations of the magnetospheres from massive stars with a dipole magnetic axis that has an arbitrary obliquity angle (β) to the stars rotation axis. As an initial direct application, we examine the global structure of co-rotating disks for tilt angles β=0, 45 and 90 degrees using ζ Pup stellar parameters as a prototype. We find that for models with rapid stellar rotation (∼ 0.5 critical rotation), accumulation surfaces closely resemble the form predicted by the analytic Rigidly Rotating Magnetosphere (RRM) model, but with a mass distribution and outer disk termination set by centrifugal breakout processes. However, some significant differences are found including warping resulting from the dynamic nature of the MHD models in contrast to static RRM models. These MHD models can be used to synthesize rotational modulation of photometric absorption and H-alpha emission for a direct comparison with observations.

Let G be the group $\text {PAff}_{+}(\mathbb R/\mathbb Z)$ of piecewise affine circle homeomorphisms or the group ${\operatorname {\mathrm {Diff}}}^{{\kern1pt}\infty }(\mathbb R/\mathbb Z)$ of smooth circle diffeomorphisms. A constructive proof that all irrational rotations are distorted in G is given.

This contribution is based on the work published by (Pinzón et al. 2021) in which we computed rotation rates for a sample of 79 young stars (∼3 Myr) in a wide range of stellar masses (from T Tauri Stars to Herbig Ae/Be stars) in in the Orion Star Formation Complex (OSFC). We study whether the magnetospheric accretion scenario (MA), valid for young low mass stars, may be applied over a wide range of stellar masses of not. Under the assumption that stellar winds powered by stellar accretion are the main source for the stellar spin down, the hypothesis of an extension of MA toward higher masses seems plausible. A comparison with Ap/Bp stars suggest that HAeBes should suffer a loss of angular momentum by a factor between 12 and 80 during the first 10 Myr in order to match the magnetic Ap/Bp zone in HR diagram.

Gas turbine blades feature multi-pass internal cooling channels, through which relatively colder air bled from the compressor is routed to cool internal walls. Under rotation, due to the influence of Coriolis force and centrifugal buoyancy, heat transfer at the trailing side enhances and that at the leading side reduces, for a radially outward flow. This non-uniform temperature distribution results in increased thermal stress, which is detrimental to blade life. In this study, a rotation configuration is presented which can negate the Coriolis force effect on heat and fluid flow, thereby maintaining uniform heat transfer on leading and trailing walls. A straight, smooth duct of unit aspect ratio is considered to demonstrate the concept and understand the fluid flow within the channel and its interaction with the walls. The new design is compared against the conventional rotation design. Numerical simulations under steady-state condition were carried out at a Reynolds number of 25000, where the Rotation numbers were varied as 0, 0.1, 0.15, 0.2, 0.25. Realisable version of k-$\varepsilon$ model was used for turbulence modelling. It was observed that new rotation (parallel) configuration’s heat transfer on leading and trailing sides were near similar, and trailing side was marginally higher compared to leading side. An interesting phenomenon of secondary Coriolis effect is reported which accounts for the minor differences in heat transfer augmentation between leading and trailing walls. Due to centrifugal buoyancy, the fluid is pushed towards the radially outward wall, resulting in a counter-rotating vortex pair, which also enhances the heat transfer on leading and trailing walls when compared to stationary case.

We give the crossing number of the join product $W_{4}+D_{n}$, where $W_{4}$ is the wheel on five vertices and $D_{n}$ consists of $n$ isolated vertices. The proof is based on calculating the minimum number of crossings between two different subgraphs from the set of subgraphs which do not cross the edges of the graph $W_{4}$ and from the set of subgraphs which cross the edges of $W_{4}$ exactly once.