Tilted Rotation and Wobbling Motion in Nuclei

The self-consistent harmonic oscillator model including the three-dimensional cranking term is extended to describe collective excitations in the random phase approximation. It is found that quadrupole collective excitations associated with wobbling motion in rotating nuclei lead to the appearance of two- or three-dimensional rotation.Comment: 9 pages, 2 Postscript figures, corrected typo

On dynamical mass generation in three dimensional supersymmetric U(1) gauge field theory

We investigate and contrast the non-perturbative infra red structure of N=1 and N=2 supersymmetric non-compact U(1) gauge field theory in three space-time dimensions with N matter flavours. We study the Dyson-Schwinger equations in a general gauge using superfield formalism; this ensures that supersymmetry is kept manifest, though leads to spurious infra red divergences which we have to avoid carefully. In the N=1 case the superfield formalism allows us to choose a vertex which satisfies the U(1) Ward identity exactly, and we find the expected critical behaviour in the wavefunction renormalization and strong evidence for the existence of a gauge independent dynamically generated mass, but with no evidence for a critical flavour number. We study the N=2 model by dimensional reduction from four dimensional N=1 electrodynamics, and we refine the old gauge dependence argument that there is no dynamical mass generation. We recognize that the refinement only holds after dimensional reduction.Comment: 32 pages RevTeX; 3 axodraw figures include

A probabilistic time geographic approach to quantifying seabird‐vessel interactions

Accounting for uncertainty is essential for precautionary approaches to managing seabird bycatch in commercial fisheries. However, there is no existing mechanism to explicitly quantify the uncertainty of seabird‐vessel interactions (i.e. co‐occurrence in space and time). Here we develop a time geographic method to measure the probability of individual birds encountering (co‐occurring within 30 km) and attending (within 5 km) individual fishing vessels. The approach involves creating voxel‐based probabilistic space–time prisms (PSTPs) to model the movements of individual birds and vessels, with trajectory data from bird‐borne GPS devices and vessel Automatic Identification Systems (AIS). We intersected these PSTPs to quantify the probability of interaction between bird‐vessel pairs over time and space. We demonstrate the approach with a case study of interactions of Endangered Toroa (Antipodean Albatross; Diomedea antipodensis antipodensis) with pelagic longline vessels in part of the South Pacific high seas. We found 15 vessels within 150 km and 3 h of two birds, yet interaction occurred with only two of those vessels. We visualised the probability of encounter and attendance over time and space and determined that interactions lasted several hours each (up to 6.2–14.1 h attendance, 20.8–26.1 h encounter for one bird‐vessel pair). Our time geographic approach adds to existing tools to quantify seabird bycatch risk by providing an explicit measure of uncertainty of seabird‐vessel interactions. We provide a flexible methodological pathway and R scripts, the application of which would allow managers to estimate interaction probability for multiple marine species and fisheries, including those with lower‐resolution positional datasets

Continuous Interaction with a Virtual Human

Attentive Speaking and Active Listening require that a Virtual Human be capable of simultaneous perception/interpretation and production of communicative behavior. A Virtual Human should be able to signal its attitude and attention while it is listening to its interaction partner, and be able to attend to its interaction partner while it is speaking – and modify its communicative behavior on-the-fly based on what it perceives from its partner. This report presents the results of a four week summer project that was part of eNTERFACE’10. The project resulted in progress on several aspects of continuous interaction such as scheduling and interrupting multimodal behavior, automatic classification of listener responses, generation of response eliciting behavior, and models for appropriate reactions to listener responses. A pilot user study was conducted with ten participants. In addition, the project yielded a number of deliverables that are released for public access

Pitch then power: limitations to acceleration in quadrupeds

Rapid acceleration and deceleration are vital for survival in many predator and prey animals and are important attributes of animal and human athletes. Adaptations for acceleration and deceleration are therefore likely to experience strong selective pressures—both natural and artificial. Here, we explore the mechanical and physiological constraints to acceleration. We examined two elite athletes bred and trained for acceleration performance (polo ponies and racing greyhounds), when performing maximal acceleration (and deceleration for ponies) in a competitive setting. We show that maximum acceleration and deceleration ability may be accounted for by two simple limits, one mechanical and one physiological. At low speed, acceleration and deceleration may be limited by the geometric constraints of avoiding net nose-up or tail-up pitching, respectively. At higher speeds, muscle power appears to limit acceleration

What are the hot R Coronae Borealis stars?

We investigate the evolutionary status of four stars: V348 Sgr, DY Cen, and MV Sgr in the Galaxy and HV 2671 in the LMC. These stars have in common random deep declines in visual brightness, which are characteristic of R Coronae Borealis (RCB) stars. RCB stars are typically cool hydrogen-deficient supergiants. The four stars studied in this paper are hotter (Teff = 15–20 kK) than the majority of RCB stars (Teff = 5000–7000 K). Although these are commonly grouped together as the hot RCB stars they do not necessarily share a common evolutionary history. We present new observational data and an extensive collection of archival and previously published data that is reassessed to ensure internal consistency. We find temporal variations of various properties on different timescales that will eventually help us to uncover the evolutionary history of these objects. DY Cen and MV Sgr have typical RCB helium abundances, which exclude any currently known post–asymptotic giant branch (post-AGB) evolutionary models. Moreover, their carbon and nitrogen abundances present us with further problems for their interpretation. V348 Sgr and HV 2671 are in general agreement with a born-again post-AGB evolution, and their abundances are similar to Wolf-Rayet central stars of planetary nebulae (PNs). The three Galactic stars in the sample have circumstellar nebulae, which produce forbidden line radiation (for HV 2671 we have no information). V348 Sgr and DY Cen have low-density, low-expansion velocity nebulae (resolved in the case of V348 Sgr), while MV Sgr has a higher density, higher expansion velocity nebula. All three stars, on the other hand, have split emission lines, which indicate the presence of an equatorial bulge but not of a Keplerian disk. In addition, the historical light curves for the three Galactic hot RCB stars show evidence for a significant fading in their maximum-light brightnesses of ~1 mag over the last 70 yr. From this we deduce that their effective temperatures increased by a few thousand degrees. If V348 Sgr is a born-again star, as we presume, this means that the star is returning from the born-again AGB phase to the phase of a central star of PN. Spectroscopically, no dramatic change is observed over the last 50 years for V348 Sgr and MV Sgr. However, there is some evidence that the winds of V348 Sgr and DY Cen have increased in strength in the last decade. HV 2671, located in the LMC, has not been analyzed in detail but at 5 Å… resolution is almost identical to V348 Sgr. Through the bolometric correction derived for V348 Sgr and the known distance, we can estimate the absolute ν magnitude of HV 2671 (Mν = -3.0 mag) and its bolometric luminosity (~6000 L⊙)

Exploring hypotheses of the actions of TGF-beta 1 in epidermal wound healing using a 3D computational multiscale model of the human epidermis

In vivo and in vitro studies give a paradoxical picture of the actions of the key regulatory factor TGF-beta 1 in epidermal wound healing with it stimulating migration of keratinocytes but also inhibiting their proliferation. To try to reconcile these into an easily visualized 3D model of wound healing amenable for experimentation by cell biologists, a multiscale model of the formation of a 3D skin epithelium was established with TGF-beta 1 literature-derived rule sets and equations embedded within it. At the cellular level, an agent-based bottom-up model that focuses on individual interacting units ( keratinocytes) was used. This was based on literature-derived rules governing keratinocyte behavior and keratinocyte/ECM interactions. The selection of these rule sets is described in detail in this paper. The agent-based model was then linked with a subcellular model of TGF-beta 1 production and its action on keratinocytes simulated with a complex pathway simulator. This multiscale model can be run at a cellular level only or at a combined cellular/subcellular level. It was then initially challenged ( by wounding) to investigate the behavior of keratinocytes in wound healing at the cellular level. To investigate the possible actions of TGF-beta 1, several hypotheses were then explored by deliberately manipulating some of these rule sets at subcellular levels. This exercise readily eliminated some hypotheses and identified a sequence of spatial-temporal actions of TGF-beta 1 for normal successful wound healing in an easy-to-follow 3D model. We suggest this multiscale model offers a valuable, easy-to-visualize aid to our understanding of the actions of this key regulator in wound healing, and provides a model that can now be used to explore pathologies of wound healing

Substructure revealed by RR Lyraes in SDSS Stripe 82

We present an analysis of the substructure revealed by 407 RR Lyraes in Sloan Digital Sky Survey (SDSS) Stripe 82. Period estimates are determined to high accuracy using a string-length method. A subset of 178 RR Lyraes with spectrally derived metallicities are employed to derive metallicity-period-amplitude relations, which are then used to find metallicities and distances for the entire sample. The RR Lyraes lie between 5 and 115 kpc from the Galactic center. They are divided into subsets of 316 RRab types and 91 RRc types based on their period, colour and metallicity. The density distribution is not smooth, but dominated by clumps and substructure. Samples of 55 and 237 RR Lyraes associated with the Sagittarius Stream and the Hercules-Aquila Cloud respectively are identified. Hence, ~ 70 % of the RR Lyraes in Stripe 82 belong to known substructure. There is a sharp break in the density distribution at Galactocentric radii of 40 kpc, reflecting the fact that the dominant substructure in Stripe 82 - the Hercules-Aquila Cloud and the Sagittarius Stream - lies within 40 kpc. In fact, almost 60 % of all the RR Lyraes in Stripe 82 are associated with the Hercules-Aquila Cloud alone, which emphasises its pre-eminence. Additionally, evidence of a new and distant substructure - the Pisces Overdensity - is found, consisting of 28 faint RR Lyraes centered on Galactic coordinates (80 deg, -55 deg) and with distances of ~ 80 kpc. The total stellar mass in the Pisces Overdensity is ~10000 solar masses and its metallicity is [Fe/H] ~ -1.5.Comment: 15 pages, submitted to MNRA

Self-directed versus peer-supported digital self-management programmes for mental and sexual wellbeing after acquired brain injury (HOPE4ABI): protocol for a feasibility randomised controlled trial

Background Acquired brain injury (ABI) can lead to biopsychosocial changes such as depression, low self-esteem and fatigue. These changes can cause, and be caused by, sexual issues affecting relationships and wellbeing. Given the relationship between sexual wellbeing and mental health, it is feasible that supporting sexual wellbeing will benefit psychological wellbeing. However, neurorehabilitation is inconsistent and often fragmented across the UK, and psychological, sexual and social support are lacking. Research shows that self-management and peer-support programmes can improve quality of life, self-efficacy and psychological wellbeing after brain injury. This protocol describes a feasibility randomised controlled trial (RCT) of a digital self-management programme to support mental and sexual wellbeing (known as HOPE4ABI), co-designed with and for people with ABI. Methods This mixed-methods feasibility RCT has two parallel trial arms of the 8-week digital HOPE4ABI self-management programme. Eligibility criteria include age > 18 years, diagnosed or suspected ABI > 3 months prior to trial entry, access to an Internet-enabled device and ability to engage with the intervention. Referrals to the study website will be made via the National Health Service (NHS), social media and partnering organisations. Sixty eligible participants will be randomised at a ratio of 1:1 to peer-supported (n = 30) or self-directed (n = 30) HOPE4ABI programmes. Primary feasibility outcomes include recruitment and retention rates, engagement, adherence and usage. Secondary outcomes related to standardised measures of quality of life, sexual wellbeing and mental wellbeing. Participants and peer facilitators will be interviewed after the course to assess acceptability across both trial arms. Discussion This feasibility trial data is not sufficiently powered for inferential statistical analyses but will provide evidence of the feasibility of a full RCT. Quantitative trial data will be analysed descriptively, and participant screening data representing age, ethnicity and gender will be presented as proportions at the group level. These data may indicate trends in reach to particular demographic groups that can inform future recruitment strategies to widen participation. Progression to a definitive trial will be justified if predetermined criteria are met, relating to recruitment, retention, engagement and acceptability. Trial registration ISRCTN46988394 registered on March 1, 2023