7,087 research outputs found
Do AGN really suppress star formation?
Active galactic nuclei (AGN) are believed to regulate star formation inside
their host galaxies through "AGN feedback". We summarise our on-going study of
luminous AGN (z~0.2-3; L_(AGN,bol)>~10^43 erg/s), which is designed to search
for observational signatures of feedback by combining observed star-formation
rate (SFR) measurements from statistical samples with cosmological model
predictions. Using the EAGLE hydrodynamical cosmological simulations, in
combination with our Herschel+ALMA surveys, we show that - even in the presence
of AGN feedback - we do not necessarily expect to see any relationships between
average galaxy-wide SFRs and instantaneous AGN luminosities. We caution that
the correlation with stellar mass for both SFR and AGN luminosity can
contribute to apparent observed positive trends between these two quantities.
On the other hand, the EAGLE simulations, which reproduce our observations,
predict that a signature of AGN feedback can be seen in the wide specific SFR
distributions of massive galaxies (not just AGN hosts). Overall, whilst
we can not rule out that AGN have an immediate small-scale impact on in-situ
star-formation, all of our results are consistent with a feedback model where
galaxy-wide in-situ star formation is not rapidly suppressed by AGN, but where
the feedback likely acts over a longer timescale than a single AGN episode.Comment: IAU Proceedings No. 356 "Nuclear Activity in Galaxies Across Cosmic
Time", M. Povic et a
Exercise therapy for the treatment of tendinopathies: a scoping review.
Purpose: Tendinopathy is a common condition leading to pain, disability and reduced quality of life/participation. Due to many tendinopathies having a chronic or recurrent course, there is a need to identify effective, evidence based practice for this condition. Exercise is the mainstay of conservative management for tendinopathy however, due to the heterogeneity of tendinopathy, populations affected and variation in exercise approaches a mapping of this area is required to inform future research, both primary and secondary and ultimately practice. The aim of this scoping review was therefore to map the existing evidence on exercise interventions and outcomes for the treatment of any tendinopathy. Methods: JBI Scoping Review methodology and an apriori protocol guided this review. Inclusion criteria included i). Participants - studies including any age or gender with any tendinopathy, ii). Concept – Exercise therapy (any type or format) intervention, delivered in any setting by any professional with any outcomes related to evaluating exercise interventions for tendinopathy, iii). Context – any setting in any developed nation listed as having very high human development. Nine databases, five clinical trial registries and six grey literature sources were searched. Results were uploaded to Covidence for screening. All screening (title/abstract and full text) were conducted by two reviewers independently with conflicts resolved by a third reviewer. A data extraction tool was iteratively developed and piloted by the review team prior to data extraction. As per scoping review methodology, no critical appraisal was conducted. Data was synthesised to present a map of tendinopathy exercise interventions and outcomes (related to ICON health related domains) alongside an accompanying narrative. Results: 22,547 studies were identified and after de-duplication and screening 554 studies were included in the review representing 25,687 participants. Studies were predominantly randomised controlled trials or systematic reviews conducted in the UK, Turkey, USA & Australia. The main tendinopathies reported were rotator cuff, achilles, lateral elbow and patellar. The majority of studies included a range of strength training approaches followed by flexibility and motor re-training /proprioception exercise. There was a range in quality of reporting of exercise across tendinopathies, assessed using the TIDieR checklist with 65.8% partially reproducible and 28% not reproducible. There was variation across tendinopathies in domains (disability, pain and physical function capacity) reported with corresponding variation in primary outcome measures related to these. Conclusion(s): This scoping review has mapped the evidence on exercise for tendinopathies. There is a range of exercise approaches across different tendinopathies and a need for future research to strictly adhere to reporting guidelines. There are a range of outcomes and domains reported across tendinopathies and future research would benefit from the development of core outcome sets for each tendinopathy. Impact: This scoping review adds to the body of evidence on tendinopathy rehabilitation. The results have informed systematic reviews currently being conducted on effectiveness of exercise for tendinopathies and the acceptability and feasibility of exercise interventions for tendinopathies. These reviews will provide guidance on exercise for tendinopathy rehabilitation, which can be adopted internationally. Funding acknowledgements: This project is funded by the National Institute for Health Research (NIHR) [Health Technology Assessment (HTA) 129388 Exercise therapy for the treatment of tendinopathies]. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care
Numerical simulations of the decay of primordial magnetic turbulence
We perform direct numerical simulations of forced and freely decaying 3D
magnetohydrodynamic turbulence in order to model magnetic field evolution
during cosmological phase transitions in the early Universe. Our approach
assumes the existence of a magnetic field generated either by a process during
inflation or shortly thereafter, or by bubble collisions during a phase
transition. We show that the final configuration of the magnetic field depends
on the initial conditions, while the velocity field is nearly independent of
initial conditions.Comment: 10 pages, 6 figures, references added, PRD accepte
Spin current and magneto-electric effect in non-collinear magnets
A new microscopic mechanism of the magneto-electric (ME) effect based on the
spin supercurrent is theoretically presented for non-collinear magnets. The
close analogy between the superconductors (charge current) and magnets (spin
current) is drawn to derive the distribution of the spin supercurrent and the
resultant electric polarization. Application to the spiral spin structure is
discussed.Comment: 5 pages, 2 figure
Long-term culture of human breast cancer specimens and their analysis using optical projection tomography
Breast cancer is a leading cause of mortality in the Western world. It is well established that the spread of breast cancer, first locally and later distally, is a major factor in patient prognosis. Experimental systems of breast cancer rely on cell lines usually derived from primary tumours or pleural effusions. Two major obstacles hinder this research: (i) some known sub-types of breast cancers (notably poor prognosis luminal B tumours) are not represented within current line collections; (ii) the influence of the tumour microenvironment is not usually taken into account. We demonstrate a technique to culture primary breast cancer specimens of all sub-types. This is achieved by using three-dimensional (3D) culture system in which small pieces of tumour are embedded in soft rat collagen I cushions. Within 2-3 weeks, the tumour cells spread into the collagen and form various structures similar to those observed in human tumours1. Viable adipocytes, epithelial cells and fibroblasts within the original core were evident on histology. Malignant epithelial cells with squamoid morphology were demonstrated invading into the surrounding collagen. Nuclear pleomorphism was evident within these cells, along with mitotic figures and apoptotic bodies. We have employed Optical Projection Tomography (OPT), a 3D imaging technology, in order to quantify the extent of tumour spread in culture. We have used OPT to measure the bulk volume of the tumour culture, a parameter routinely measured during the neo-adjuvant treatment of breast cancer patients to assess response to drug therapy. Here, we present an opportunity to culture human breast tumours without sub-type bias and quantify the spread of those ex vivo. This method could be used in the future to quantify drug sensitivity in original tumour. This may provide a more predictive model than currently used cell lines.Publisher PDFPeer reviewe
Relationship between eruptions of active-region filaments and associated flares and CMEs
To better understand the dynamical process of active-region filament
eruptions and associated flares and CMEs, we carried out a statistical study of
120 events observed by BBSO, TRACE, and t(SOHO/EIT) from 1998 to 2007 and
combined filament observations with the NOAA's flare reports, MDI magnetograms,
and LASCO data, to investigate the relationship between active-region filament
eruptions and other solar activities. We found that 115 out of 120 filament
eruptions are associated with flares. 56 out of 105 filament eruptions are
found to be associated with CMEs except for 15 events without corresponding
LASCO data. We note the limitation of coronagraphs duo to geometry or
sensitivity, leading to many smaller CMEs that are Earth-directed or well out
of the plane of sky not being detected by near-Earth spacecraft. Excluding
those without corresponding LASCO data, the CME association rate of
active-region filament eruptions clearly increases with X-ray flare class from
about 32% for C-class flares to 100% for X-class flares. The eruptions of
active-region filaments associated with Halo CMEs are often accompanied by
large flares. About 92% events associated with X-class flare are associated
with Halo CMEs. Such a result is due to that the Earth-directed CMEs detected
as Halo CMEs are often the larger CMEs and many of the smaller ones are not
detected because of the geometry and low intensity. The average speed of the
associated CMEs of filament eruptions increases with X-ray flare size from
563.7 km/s for C-class flares to 1506.6 km/s for X-class flares. Moreover, the
magnetic emergence and cancellation play an important role in triggering
filament eruptions. These findings may be instructive to not only in respect to
the modeling of active-region filament eruptions but also in predicting flares
and CMEs.Comment: 19 Pages, 7 figures, Accepted for publication in MNRA
Going From an Academic Medical Center to a Community Hospital: Patient Experiences with TransfersGoing from an academic medical center to a community hospital: Patient experiences with transfers
Academic medical centers (AMCs) often operate at or near full capacity, which leads to delays in care while smaller community hospitals may have excess capacity. To address this issue and to match patient needs to care acuity, patients may be transferred from an AMC emergency department for direct admission to a community hospital. We aimed to explore the experiences and perspectives of patients who were transferred. We randomly selected patients transferred between February 2019 and February 2020. We conducted structured thirty-minute interviews containing fixed response and open-ended questions focusing on the transfer rationale and experience, care quality, and patient financial outcomes. We used descriptive statistics to summarize questions with fixed responses and thematic analysis for open-ended questions. We interviewed a total of 40 patients. While most (88%) understood the rationale for transfer, many (60%) did not feel they had agency in the decision despite the voluntary nature of the program. Patients generally had a positive experience with the transfer (65%) and valued the expedited admission. However, some highlighted issues with transfer-related billing and the mismatch between the expectations of presenting to an academic hospital and the reality of being admitted to a community one. We conclude that patients are amenable to transfers for an expedited admission and understand the rationale for such transfers. However, participants should receive a clear explanation of benefits to them, guidance that the program is voluntary, and protection from financial risk
Experience Framework
This article is associated with the Patient, Family & Community Engagement lens of The Beryl Institute Experience Framework (https://www.theberylinstitute.org/ExperienceFramework). Access other PXJ articles related to this lens. Access other resources related to this lens
First Remote Sensing Observations of Trifluoromethane (HFC-23) in the Upper Troposphere and Lower Stratosphere
This work reports the first remote sensing measurements of atmospheric HFC-23 (CHF3) using solar occultation measurements made by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS) and the Jet Propulsion Laboratory Mark IV (MkIV) balloon interferometer. A total of 8809 ACE occultations measured between 2004 and 2010 have been processed, along with 24 MkIV occultations measured between 1989 and 2007. ACE data (yearly averages over the 10-25 km altitude range) in the tropics/subtropics (40°S-40°N) reveal a trend of 4.0 ± 1.6% per year in the growth of HFC-23 for 2004-2009 (or 3.9 ± 1.2% per year for 2004-2010), slightly smaller than surface measurements from Cape Grim air archive samples over the same time period (4.7 ± 0.3% per year). The northern midlatitude and high-latitude MkIV data (averaged over the 10-25 km altitude range) indicate a growth rate of 5.8 ± 0.3% per year over the period 1989-2007 (5.3 ± 0.4% per year for just the midlatitude data), similar to the Cape Grim surface trend of 5.7 ± 0.1% per year over the same period. The absolute HFC-23 volume mixing ratios measured by ACE and MkIV in the upper troposphere/lower stratosphere are in good agreement (\u3c5% bias) with each other but are ∼30% larger than ground-based measurements. The source of this bias has not been definitively ascertained; however, spectroscopic errors are the most likely cause. Copyright 2012 by the American Geophysical Union
Standards in sustainable engineering and design
The financial and environmental costs associated with the manufacture and consumption of products may be reduced through design for efficient production, service life extension and post-consumer value recovery. In response to today’s need to design with consideration for the whole product life cycle, British Standards Institution (BSI) published BS 8887-1 (2006) Design for Manufacture, Assembly, Disassembly and End-of-life processing (MADE). Original research into the distribution and use of this first part of the MADE series is reported in this thesis. The organizations that accessed BS 8887-1 were categorised using their Standard Industrial Classification (SIC) code. The results are presented graphically in multilevel charts using the hierarchical structure of the SIC system. The study found that the majority of standards users that purchased or downloaded BS 8887-1 were companies in the manufacturing sector and particularly electronics producers. Educational institutions also showed high levels of interest in the standard. For the first time, the use of BS 8887-1 in practice has been investigated. The purpose was to discover if, why and how it is being used and to identify examples of its application in design practice. This was accomplished through semi-structured interviews with design practitioners from both industry and academia, thus helping to explain the results of the earlier SIC study. The information gathered through the interviews shows how BS 8887-1 has informed the design process and how it has been used in combination with various design and management techniques e.g. Advanced Product Quality Planning (APQP). These studies suggest that demand for the standard has been stimulated by the introduction of Extended Producer Responsibility (EPR) legislation, especially the Waste Electrical and Electronic Equipment (WEEE) directive. Importantly, the use of BS 8887-1 has been found to be helpful in winning new business and reducing the costs associated with manufacture, product maintenance and waste management. Based on the result of the qualitative research, a new model of the use of standards in the New Product Development (NPD) process is presented. The research was proposed by the Chairman of the BSI technical committee responsible for the BS 8887 series. The beneficiaries are BSI, industry and academia, since the investigation has shown BS 8887-1 to be of value, and has informed the continuing development of this series of standards. The thesis concludes by arguing for BS 8887 to become the basis of an International Organization for Standardization (ISO) standard in order to reach a wider audience. It also identifies a need for the standard’s design requirements to be supported with additional supplementary interpretation expanding on, and adding detail to, the information in the standard itself. Influenced by this research, at the time of writing a new BSI working group was being formed to consider developing BS 8887 as an ISO standard. BSI had also begun the process of commissioning a handbook to assist designers in the practical application of BS 8887 in industrial design.EThOS - Electronic Theses Online ServiceGBUnited Kingdo
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