Calculation of Effective Coulomb Interaction for Pr3+Pr^{3+}, U4+U^{4+}, and UPt3UPt_3

In this paper, the Slater integrals for a screened Coulomb interaction of the the Yukawa form are calculated and by fitting the Thomas-Fermi wavevector, good agreement is obtained with experiment for the multiplet spectra of $Pr^{3+}$ and $U^{4+}$ ions. Moreover, a predicted multiplet spectrum for the heavy fermion superconductor $UPt_3$ is shown with a calculated Coulomb U of 1.6 eV. These effective Coulomb interactions, which are quite simple to calculate, should be useful inputs to further many-body calculations in correlated electron metals.Comment: 8 pages, revtex, 3 uuencoded postscript figure

The <i>M^.–M</i>_disk Relationship for Herbig Ae/Be Stars: A lifetime problem for disks with low masses?

The accretion of material from protoplanetary disks onto their central stars is a fundamental process in the evolution of these systems and a key diagnostic in constraining the disk lifetime. We analyze the relationship between the stellar accretion rate and the disk mass in 32 intermediate-mass Herbig Ae/Be systems and compare them to their lower-mass counterparts, T Tauri stars. We find that the M ̇-Mdisk relationship for Herbig Ae/Be stars is largely flat at ∼10−7 M☉ yr−1 over 3 orders of magnitude in dust mass. While most of the sample follows the T Tauri trend, a subset of objects with high accretion rates and low dust masses are identified. These outliers (12 out of 32 sources) have an inferred disk lifetime of less than 0.01 Myr and are dominated by objects with low infrared excess. This outlier sample is likely identified in part by the bias in classifying Herbig Ae/Be stars, which requires evidence of accretion that can only be reliably measured above a rate of ∼10−9M☉ yr−1 for these spectral types. If the disk masses are not underestimated and the accretion rates are not overestimated, this implies that these disks may be on the verge of dispersal, which may be due to efficient radial drift of material or outer disk depletion by photoevaporation and/or truncation by companions. This outlier sample likely represents a small subset of the larger young, intermediate-mass stellar population, the majority of which would have already stopped accreting and cleared their disks

Free Fermions and Thermal AdS/CFT

The dynamics of finite temperature U(N) gauge theories on $S^3$ can be described, at weak coupling, by an effective unitary matrix model. Here we present an exact solution to these models, for any value of $N$, in terms of a sum over representations. Taking the large $N$ limit of this solution provides a new perspective on the deconfinement transition which is supposed to be dual to the Hawking-Page transition. The large $N$ phase transition manifests itself here in a manner similar to the Douglas-Kazakov phase transition in 2d Yang-Mills theory. We carry out a complete analysis of the saddle representation in the simplest case involving only the order parameter ${\rm Tr}U$. We find that the saddle points corresponding to thermal $AdS$, the small black hole and the large black hole can all be described in terms of free fermions. They all admit a simple phase space description {\it a la} the BPS geometries of Lin, Lunin and Maldacena.Comment: (0+34) pages and 9 figures, v2 references adde

Three electron beams from a laser-plasma wakefield accelerator and the energy apportioning question

Laser-wakefield accelerators are compact devices capable of delivering ultra-short electron bunches with pC-level charge and MeV-GeV energy by exploiting the ultra-high electric fields arising from the interaction of intense laser pulses with plasma. We show experimentally and through numerical simulations that a high-energy electron beam is produced simultaneously with two stable lower-energy beams that are ejected in oblique and counter-propagating directions, typically carrying off 5-10% of the initial laser energy. A MeV, 10s nC oblique beam is ejected in a 30-60 degree hollow cone, which is filled with more energetic electrons determined by the injection dynamics. A nC-level, 100s keV backward-directed beam is mainly produced at the leading edge of the plasma column. We discuss the apportioning of absorbed laser energy amongst the three beams. Knowledge of the distribution of laser energy and electron beam charge, which determine the overall efficiency, is important for various applications of laser-wakefield accelerators, including the development of staged high-energy accelerators

Wide-angle electron beams from laser-wakefield accelerators

Advances in laser technology have driven the development of laser-wakefield accelerators, compact devices that are capable of accelerating electrons to GeV energies over centimetre distances by exploiting the strong electric field gradients arising from the interaction of intense laser pulses with an underdense plasma. A side-effect of this acceleration mechanism is the production of high-charge, low-energy electron beams at wide angles. Here we present an experimental and numerical study of the properties of these wide-angle electron beams, and show that they carry off a significant fraction of the energy transferred from the laser to the plasma. These high-charge, wide-angle beams can also cause damage to laser-wakefield accelerators based on capillaries, as well as become source of unwanted bremsstrahlung radiation

Home health monitoring around the time of surgery: a qualitative study of patients’ experiences before and after joint replacement

Objectives: Hip and knee replacements are common major elective surgical interventions with over 200,000 performed annually in the UK. Not all patients achieve optimal outcomes or experience problems or delays in recovery. The number of patients needing these operations are set to increase and routine clinical monitoring is time and resource consuming for patients and healthcare providers, therefore innovative evaluation of surgical outcomes are needed. The aim of this qualitative study was to capture the patient experience of living with a novel home monitoring sensing system during the period around joint replacement. Setting: One secondary care hospital in the South West, UK Participants: 13 patients, (8 female, 63-89y) undergoing total hip or knee replacement enrolled into the study Design: Qualitative study with thematic analysis. The system remained in situ for up to 12 weeks after their surgery and comprised a group of low powered sensors monitoring the environment (temperature, light and humidity) and activity of people within the home. Patients were interviewed at two timepoints: before and after surgery. Interviews explored views about living with the technology, its acceptability as well as attitudes towards health technology. Results: Three main themes emerged: installation of home sensing technology on the journey to surgery; the home space and defining unobtrusiveness and pivotal role of social support networks Conclusions: Patients who agreed to the technology found living with it acceptable. A home sensing system that monitors the environment and activity of the people in the home could provide an innovative way of assessing patients’ surgical outcomes. At a time, characterised by reduced mobility, functional limitations and increased pain, patients in this study relied on informal and formal supportive networks to help maintain the system through the busy trajectory of the perioperative period. Strengths and limitations of this study • In-depth one-to-one interviews provided insight into patients’ real experiences and views as they lived with the technology in their own homes • Although the sample size was small, lacked ethnic diversity and only included people willing to have technology installed in their homes, there was good diversity in age and gender and some diversity in patients undergoing hip and knee replacement • Use of thematic analysis enabled robust analysis of data, including focus on the acceptability of the technology in real health-related circumstances

Bosonization of non-relativstic fermions in 2-dimensions and collective field theory

We revisit bosonization of non-relativistic fermions in one space dimension. Our motivation is the recent work on bubbling half-BPS geometries by Lin, Lunin and Maldacena (hep-th/0409174). After reviewing earlier work on exact bosonization in terms of a noncommutative theory, we derive an action for the collective field which lives on the droplet boundaries in the classical limit. Our action is manifestly invariant under time-dependent reparametrizations of the boundary. We show that, in an appropriate gauge, the classical collective field equations imply that each point on the boundary satisfies Hamilton's equations for a classical particle in the appropriate potential. For the harmonic oscillator potential, a straightforward quantization of this action can be carried out exactly for any boundary profile. For a finite number of fermions, the quantum collective field theory does not reproduce the results of the exact noncommutative bosonization, while the latter are in complete agreement with the results computed directly in the fermi theory.Comment: references added and typos corrected; 21 pages, 3 figures, eps

Using home sensing technology to assess outcome and recovery after joint replacement – findings from the hip and knee study of a sensor platform of healthcare in a residential environment

Purpose: Improving outcomes after joint replacement is a key research priority. After joint replacement, up to 30% of patients report minimal improvement or their symptoms get worse and not all patients are satisfied with their outcome. Poor outcomes include continuing pain, functional limitation and increased healthcare utilisation. Patient Reported Outcome Measures (PROMs) such as the Oxford Hip or Oxford Knee Score and the EQ-5D, a measure of health status, are widely used to assess outcome after joint replacement in practice and research. These measures can assess a variety of health outcomes including pain, function and health related quality of life. Though widely used, many PROMs have methodological limitations and there is debate about how to interpret results and definitions of clinically meaningful change. Previously, research has explored the relationship between PROMs and objective measures, such as timed walks or sit-to-stand tests. Such objective measures are administered in controlled, laboratory style settings, and may not reflect levels of activity in daily life. With the rapid development of monitoring technology, there is opportunity to characterise the relationship between PROMs and behaviour in a natural setting and to develop methods of passive monitoring of outcome and recovery after surgery. We are working with a multidisciplinary team which has developed a system of low powered sensors that can monitor the health-related behaviours of people living at home. The system includes: sensors for the home environment (measuring temperature, humidity, room occupancy, water and electricity usage) a wrist-band body-worn activity monitor and silhouette (body outline) sensors. The SPHERE system of sensors is now being installed in 100 homes belonging to the general population. Within this cohort we are installing the system in the homes of 20 patients who are about to undergo a total hip or knee replacement (THR/TKR). The study aims to: (a) determine to what extent the sensory data obtained from the SPHERE system is comparable to data obtained from routine clinical measures and PROMs in the assessment of patients' activity, function and recovery processes; (b) investigate whether the sensory data can detect meaningful changes in recovery. Methods: To assess the accuracy and usefulness of the sensory data, in this 1-year observational study, patients will be provided with the sensor system to monitor and record daily continuous measurements. We will make and refine appropriate data learning outcomes with the quantitative data e.g., daily measurements in the weeks parallel to the distribution of PROM assessments pre/post-operative (4–9 days, 6 and 12 weeks) and weekly measurements during the other months. The study will assess the relationships between environmental, behavioural and movement data and the parameters of interest from the PROMs assessments over time. Interviews and focus groups with patients and health professional will provide qualitative data and achieve depth in understanding the accuracy of the data, its usefulness for health professionals in decision making, and if the technology is acceptable. Results: The SPHERE sensor system has been installed in the homes of two patients. We aim to recruit up to 20 patients, (aged 18 years or over) whom are due to undergo a TKR or THR in the UK. Conclusions: This study will provide a unique understanding of home and wearable sensor technology in an orthopaedic population and will compare sensor data with current PROMs

Unravelling plant responses to stress—the importance of targeted and untargeted metabolomics

Climate change and an increasing population, present a massive global challenge with respect to environmentally sustainable nutritious food production. Crop yield enhancements, through breeding, are decreasing, whilst agricultural intensification is constrained by emerging, re-emerging, and endemic pests and pathogens, accounting for ~30% of global crop losses, as well as mounting abiotic stress pressures, due to climate change. Metabolomics approaches have previously contributed to our knowledge within the fields of molecular plant pathology and plant–insect interactions. However, these remain incredibly challenging targets, due to the vast diversity in metabolite volatility and polarity, heterogeneous mixtures of pathogen and plant cells, as well as rapid rates of metabolite turn-over. Unravelling the systematic biochemical responses of plants to various individual and combined stresses, involves monitoring signaling compounds, secondary messengers, phytohormones, and defensive and protective chemicals. This demands both targeted and untargeted metabolomics approaches, as well as a range of enzymatic assays, protein assays, and proteomic and transcriptomic technologies. In this review, we focus upon the technical and biological challenges of measuring the metabolome associated with plant stress. We illustrate the challenges, with relevant examples from bacterial and fungal molecular pathologies, plant–insect interactions, and abiotic and combined stress in the environment. We also discuss future prospects from both the perspective of key innovative metabolomic technologies and their deployment in breeding for stress resistance

Using home sensing technology to assess outcome and recovery after hip and knee replacement in the UK: the HEmiSPHERE study protocol

Abstract Introduction Over 160 000 people with severe hip or knee pain caused by osteoarthritis undergo total hip (THR) or knee replacement (TKR) surgery each year in the UK within the National Health Service (NHS), and this number is expected to increase. Innovative approaches to evaluating surgical outcomes will be needed to respond to the increasing burden of joint replacement surgery. The Sensor Platform for Healthcare in a Residential Environment, Interdisciplinary Research Collaboration (SPHERE-IRC) have developed a system of sensors that can monitor the health-related behaviours of people living at home. The system includes sensors for the home environment (measuring temperature, humidity, room occupancy, water and electricity usage), a wristband body-worn activity monitor and silhouette (body outline) sensors. The aim of HEmiSPHERE (Hip and knEe study of a Sensor Platform of HEalthcare in a Residential Environment) is to (1) determine the accuracy and feasibility of the sensory data as it compares with conventional assessment of health outcomes after surgery using patient self-reported questionnaires, and (2) to explore how the SPHERE system is useful for everyday clinical decision-making. Methods and analysis A feasibility study recruiting and installing the SPHERE system in the homes of up to 30 NHS adult patients as they undergo a THR or TKR. Through a mixed-methods design, the SPHERE system will monitor and record continuous measurements of daily behaviour. Main outcomes will assess the relationships between environmental, behavioural and movement data and the parameters of interest from the standard clinical assessments measuring patient outcomes over time. Patient interviews and focus groups with consultant orthopaedic surgeons will provide in-depth understanding of the acceptability, feasibility and accuracy of the data. Ethics and dissemination We aim to disseminate the findings through regional talks and seminars, international conferences and peer-reviewed journals and social media