695915 research outputs found
Sort by
Searching for obscured AGN in z ∼ 2 submillimetre galaxies xx
No full textAims. Submillimetre-selected galaxies (SMGs) at high redshift (z ∼ 2) are potential host galaxies of active galactic nuclei (AGN). If the local Universe is a good guide, ∼50% of the obscured AGN amongst the SMG population could be missed even in the deepest X-ray surveys. Radio observations are insensitive to obscuration; therefore, very long baseline interferometry (VLBI) can be used as a tool to identify AGN in obscured systems. A well-established upper limit to the brightness temperature of 105 K exists in star-forming systems, thus VLBI observations can distinguish AGN from star-forming systems via brightness temperature measurements.Methods. We present 1.6 GHz European VLBI Network (EVN) observations of four SMGs (with measured redshifts) to search for evidence of compact radio components associated with AGN cores. For two of the sources, e-MERLIN images are also presented.Results. Out of the four SMGs observed, we detect one source, J123555.14, that has an integrated EVN flux density of 201 ± 15.2 μJy, corresponding to a brightness temperature of 5.2 ± 0.7 × 105 K. We therefore identify that the radio emission from J123555.14 is associated with an AGN. We do not detect compact radio emission from a possible AGN in the remaining sources (J123600.10, J131225.73, and J163650.43). In the case of J131225.73, this is particularly surprising, and the data suggest that this may be an extended, jet-dominated AGN that is resolved by VLBI. Since the morphology of the faint radio source population is still largely unknown at these scales, it is possible that with a ∼10 mas resolution, VLBI misses (or resolves) many radio AGN extended on kiloparsec scales
Role of SSI on seismic performance of nuclear reactors: A case study for a UK nuclear site
No full textThe role of soil-structure interaction (SSI) on the risk of unacceptable performance of five non-structural components of a nuclear reactor is investigated through a representative case study consisting of a pressurized-water reactor sited at Holyhead, United Kingdom. The seismic hazard at the site is defined by a 10,000 years uniform hazard spectrum, and its corresponding design response spectrum computed for a target structural performance goal of 1 × 10−5. Nine hypothetical soil profiles, with shear wave velocities ranging from 300 m/s to 1,200 m/s, are considered. Non-linear site response analyses are performed to determine the input motion at the foundation level; seismic capacity and demand of the components are computed using response-history analyses. To obtain high-confidence performance estimates from a limited number of results, Monte-Carlo simulation is used to expand the seismic demand matrix. It is shown that the probability of unacceptable performance of the reactor is highly sensitive to SSI effects. Specifically, the beneficial effects induced by SSI on the seismic performance of the reactor are limited to models sited on stiffer soil deposits (ie, Vs ≥ 900 m/s), whereas, the median probability of unacceptable performance increases for medium-to-soft deposits
Complex care needs and devolution in Greater Manchester: a pilot study to explore social care innovation in newly integrated service arrangements for older people
No full textObjective To describe emergent approaches to integrated care for older people with complex care needs and investigate the viability of measuring it.MethodsA case study approach was used. Sites were recruited following discussion with senior staff in health and social care agencies. Service arrangements were categorised using a framework developed by the researchers. To investigate joint working within the sites the Development Model for Integrated Care was adapted and administered to the manager of each service. Data were collected in 2018.Results Six case study sites were recruited illustrating adult social care services partnerships in services for older people with homecare providers, mental health and community nursing services. Most were established in 2018. Service arrangements were characterised by joint assessment and informal face-to-face discussions between staff. The development of an infrastructure to promote partnership working was evident between adult social care and each of the other services and most developed with home care providers. There was little evidence of a sequential approach to the development of integrated working practices.Conclusion Components of partnerships promoting integrated care have been highlighted and understanding of the complexity of measuring it enhanced. Means of information sharing and work force development require further consideration.<br/
The relationship between attachment and functioning for people with serious mental illness: A systematic review
No full textAims. Functional impairment is a hallmark feature of severe mental health problems (SMI). Attachment theory is a key psychological theory of interpersonal functioning and difficulties in attachment are common in SMI and may help explain functioning problems in SMI. This systematic review aimed to synthesis and critically appraise existing literature exploring associations between adult attachment style and functioning in SMI samples. Method. Following PRISMA guidelines we systematically searched five databases uses strings of terms relating to both attachment and social functioning. Inclusion criteria were samples diagnosed with SMI and validated measure tools. Results: Ten studies met inclusion criteria. Considerable heterogeneity was found across studies in relation to construct measurement, sample size and gender distribution. However, as predicted there was some evidence to suggest that secure attachment is associated with better functioning, and insecure attachment (specifically anxious style) is associated with impairments in functioning. Conclusion. Findings highlight the importance of considering attachment in relation to functional outcome when working with people with SMI, particularly when assessing, formulating and delivering psychological interventions
Foreign lenders’ adoption of performance pricing provisions in syndicated loans
No full textWe examine foreign lenders’ use of performance pricing provisions (PPPs) in syndicated loan contracts. First, we find that foreign lenders, as a result of both higher information asymmetry and greater renegotiation costs than their domestic counterparts, adopt PPPs instead of tight covenants in their contracts. Second, foreign lenders have a greater preference for PPPs based on credit ratings as opposed to those based on accounting ratios than their domestic counterparts. This is consistent with informationally disadvantaged foreign lenders valuing rating-based PPPs’ signaling role, with the role of accounting-based PPPs addressing the hold-up problem being less relevant to them. In addition, the above effects mainly exist when foreign lenders serve as participants rather than lead arrangers in the syndicate. Overall, our findings establish the important role played by rating-based PPPs in addressing foreign participant lenders’ information asymmetry and thereby promoting cross-border lending
Polygenic risk score opportunities for early detection and prevention strategies in endometrial cancer
No full textRecent large-scale genetic studies, particularly genome-wide association studies (GWAS), have emphasized the importance of common genetic variation in endometrial cancer susceptibility. Although each of these variants only confer modest effects on endometrial cancer risk, together they are likely to explain a substantial amount of the familial relative risk of the disease. Therefore, methods to combine genetic risk variants, such as polygenic risk scores (PRS) have gained traction as an attractive method for individualized risk prediction and management. Here, we discuss the benefits of a PRS for endometrial cancer and considerations required for clinical implementation
Control of laminar flow separation over a backward-facing rounded ramp with C-D riblets – The effects of riblet height, spacing and yaw angle
No full textIn the work presented in this paper, a section of convergent-divergent (C-D) riblets is applied upstream of a backward-facing rounded ramp in a fully developed laminar channel flow at a Reynolds number based on the channel height of 400. Numerical simulations are undertaken to examine the effects of riblet geometry and yaw angle on the strength of secondary flow produced by the riblets and the extent of flow separation zone. It is found that, in comparison with the baseline case with no riblets, flow separation is delayed and the reattachment occurs earlier leading to a smaller separation zone around the diverging line. The opposite phenomenon occurs around the converging line. Our results also show that for riblets with a given height a maximum strength of the secondary flow motion upstream of the ramp and a maximum reduction in the spanwise-averaged length of separation are obtained at s/h = 4. At a given s/h = 4, as the riblet height increases, the strength of the secondary flow motion generated by C-D riblets increases and a minimum riblet height of 3.75% of the channel height is required to produce a net reduction in the spanwise-averaged length of separation. For riblets with a given height and spacing, as yaw angle increases both the strength of secondary flow and net reduction of separation zone exhibit a parabolic trend and both of them peak at γ = 45o. Overall, with the riblet setting tested here the benefit of suppressing the laminar separation bubble has not resulted in a net reduction in the total pressure losses compared to that in the baseline case. Nevertheless, an examination of the pressure losses from three different sections along the channel separately has produced some insights about the loss mechanisms and pointed to the possible ways by which the pressure losses could be reduced
An efficient new static scheduling heuristic for accelerated architectures?
No full textHeterogeneous architectures that use Graphics Processing Units (GPUs) for general computations, in addition to multicore CPUs, are increasingly common in high-performance computing. However many of the existing methods for scheduling precedence-constrained tasks on such platforms were intended for more diversely heterogeneous clusters, such as the classic Heterogeneous Earliest Finish Time (HEFT) heuristic. We propose a new static scheduling heuristic called Heterogeneous Optimistic Finish Time (HOFT) which exploits the binary heterogeneity of accelerated platforms. Through extensive experimentation with custom software for simulating task scheduling problems on user-defined CPU-GPU platforms, we show that HOFT can obtain schedules at least 5% shorter than HEFT’s for medium-to-large numerical linear algebra application task graphs and around 3% shorter on average for a large collection of randomly-generated graphs
Broken mirror symmetry in excitonic response of reconstructed domains in twisted MoSe2/MoSe2 bilayers
No full textVan der Waals heterostructures obtained via stacking and twisting have been used to create moiré superlattices1, enabling new optical and electronic properties in solid-state systems. Moiré lattices in twisted bilayers of transition metal dichalcogenides (TMDs) result in exciton trapping2-5, host Mott insulating and superconducting states6, and act as unique Hubbard systems7-9 whose correlated electronic states can be detected and manipulated optically. Structurally, these twisted heterostructures feature atomic reconstruction and domain formation10-14. However, due to the nanoscale sizes of moiré domains, the effects of atomic reconstruction on the electronic and excitonic properties could not be systematically investigated. Here, we use near 0o twist angle MoSe2/MoSe2 bilayers with large rhombohedral AB/BA domains15 to directly probe excitonic properties of individual domains with far-field optics. We show that this system features broken mirror/inversion symmetry, with the AB and BA domains supporting interlayer excitons with out-of-plane electric dipole moments in opposite directions. The dipole orientation of ground-state -K interlayer excitons can be flipped with electric fields, while higher-energy K-K interlayer excitons undergo field-asymmetric hybridization with intralayer K-K excitons. Our study reveals the impact of crystal symmetry on TMD excitons and points to new avenues for realizing topologically nontrivial systems16,17, exotic metasurfaces18, collective excitonic phases19, and quantum emitter arrays20,21 via domain-pattern engineering