2,395 research outputs found
Modelling for potentiometric surface management of multilayer aquifer systems
Assuring the long-term availability of groundwater of adequate quality and quantity frequently requires the implementation of appropriate ground-water and conjunctive water management strategies. Presented is a model for developing optimal strategies for an multilayer aquifer in which stream-aquifer interflow is affected by the potentiometric surface and ground-water use. The model is applied to the Salt Lake Valley. Discussed is the use of pumping to control: l) potential migration of non-point source agricultural contaminants between aquifer layers and 2) the movement of a mile-long plume caused by mining waste
The frequency and properties of young tidal dwarf galaxies in nearby gas-rich groups
We present high-resolution Giant Metrewave Radio Telescope (GMRT) HI
observations and deep Canada-France-Hawaii Telescope (CFHT) optical imaging of
two galaxy groups: NGC 4725/47 and NGC 3166/9. These data are part of a
multi-wavelength unbiased survey of the gas-rich dwarf galaxy populations in
three nearby interacting galaxy groups. The NGC 4725/47 group hosts two tidal
knots and one dIrr. Both tidal knots are located within a prominent HI tidal
tail, appear to have sufficient mass (M_gas~10^8 M_sol) to evolve into
long-lived tidal dwarf galaxies (TDGs) and are fairly young in age. The NGC
3166/9 group contains a TDG candidate, AGC 208457, at least three dIrrs and
four HI knots. Deep CFHT imaging confirms that the optical component of AGC
208457 is bluer -- with a 0.28 mag g-r colour -- and a few Gyr younger than its
purported parent galaxies. Combining the results for these groups with those
from the NGC 871/6/7 group reported earlier, we find that the HI properties,
estimated stellar ages and baryonic content of the gas-rich dwarfs clearly
distinguish tidal features from their classical counterparts. We optimistically
identify four potentially long-lived tidal objects associated to three separate
pairs of interacting galaxies, implying that TDGs are not readily produced
during interaction events as suggested by some recent simulations. The tidal
objects examined in this survey also appear to have a wider variety of
properties than TDGs of similar mass formed in current simulations of
interacting galaxies, which could be the result of pre- or post-formation
environmental influences.Comment: 18 pages, 14 figures, accepted for publication in MNRA
Rationale, design and methods of the Study of Work and Pain (SWAP): a cluster randomised controlled trial testing the addition of a vocational advice service to best current primary care for patients with musculoskeletal pain (ISRCTN 52269669)
Background
Musculoskeletal pain is a major contributor to short and long term work absence. Patients
seek care from their general practitioner (GP) and yet GPs often feel ill-equipped to deal with
work issues. Providing a vocational case management service in primary care, to support
patients with musculoskeletal problems to remain at or return to work, is one potential
solution but requires robust evaluation to test clinical and cost-effectiveness.
Methods/Design
This protocol describes a cluster randomised controlled trial, with linked qualitative
interviews, to investigate the effect of introducing a vocational advice service into general
practice, to provide a structured approach to managing work related issues in primary care
patients with musculoskeletal pain who are absent from work or struggling to remain in work.
General practices (n = 6) will be randomised to offer best current care or best current care
plus a vocational advice service. Adults of working age who are absent from or struggling to
remain in work due to a musculoskeletal pain problem will be invited to participate and 330
participants will be recruited. Data collection will be through patient completed
questionnaires at baseline, 4 and 12 months. The primary outcome is self-reported work
absence at 4 months. Incremental cost-utility analysis will be undertaken to calculate the cost
per additional QALY gained and incremental net benefits. A linked interview study will
explore the experiences of the vocational advice service from the perspectives of GPs, nurse
practitioners (NPs), patients and vocational advisors.
Discussion
This paper presents the rationale, design, and methods of the Study of Work And Pain
(SWAP) trial. The results of this trial will provide evidence to inform primary care practice
and guide the development of services to provide support for musculoskeletal pain patients
with work-related issues.
Trial registration
Current Controlled Trials ISRCTN52269669
Pre-existing dwarfs, tidal knots and a tidal dwarf galaxy: an unbiased H_I study of the gas-rich interacting galaxy group NGCâ3166/9
We present Arecibo Legacy Fast ALFA (ALFALFA) and follow-up Giant Metrewave Radio Telescope (GMRT) Hâ_I observations of the gas-rich interacting group NGCâ3166/9. The sensitive ALFALFA data provide a complete census of Hâ_I-bearing systems in the group while the high-resolution GMRT data elucidate their origin, enabling one of the first unbiased physical studies of gas-rich dwarf companions and the subsequent identification of second-generation, tidal dwarf galaxies in a nearby group. The ALFALFA maps reveal an extended Hâ_I envelope around the NGCâ3166/9 group core, which we mosaic at higher resolution using six GMRT pointings spanning âŒ1âdeg^2. A thorough search of the GMRT data cube reveals eight low-mass objects with gas masses ranging from 4 Ă 10^7 to 3 Ă 10^8 M_â and total dynamical masses up to 1.4 Ă 10^9 M_â. A comparison of the HâI fluxes measured from the GMRT data to those measured in the ALFALFA data suggests that a significant fraction (âŒ60 per cent) of the Hâ_I is smoothly distributed on scales greater than 1 arcmin (âŒ7âkpc at the NGCâ3166/9 distance). We compute stellar masses and star formation rates for the eight low-mass GMRT detections, using ancillary Sloan Digital Sky Survey (SDSS) and Galaxy Evolution Explorer (GALEX) data, and use these values to constrain their origin. Most of the detections are likely to be either pre-existing dwarf irregular galaxies or short-lived, tidally formed knots; however, one candidate, AGCâ208457, is clearly associated with a tidal tail extending below NGCâ3166, exhibits a dynamical to gas mass ratio close to unity and has a stellar content and star formation rate that are broadly consistent with both simulated as well as candidate tidal dwarf galaxies from the literature. Our observations therefore strongly suggest that AGCâ208457 is a tidal dwarf galaxy
The influence of 'significant others' on persistent back pain and work participation: a qualitative exploration of illness perceptions
Background
Individual illness perceptions have been highlighted as important influences on clinical outcomes for back pain. However, the illness perceptions of 'significant others' (spouse/partner/close family member) are rarely explored, particularly in relation to persistent back pain and work participation. The aim of this study was to initiate qualitative research in this area in order to further understand these wider influences on outcome.
Methods
Semi-structured interviews based on the chronic pain version of the Illness Perceptions Questionnaire-Revised were conducted with a convenience sample of UK disability benefit claimants, along with their significant others (n=5 dyads). Data were analysed using template analysis.
Results
Significant others shared, and perhaps further reinforced, claimants' unhelpful illness beliefs including fear of pain/re-injury associated with certain types of work and activity, and pessimism about the likelihood of return to work. In some cases, significant others appeared more resigned to the permanence and negative inevitable consequences of the claimant's back pain condition on work participation, and were more sceptical about the availability of suitable work and sympathy from employers. In their pursuit of authenticity, claimants were keen to stress their desire to work whilst emphasising how the severity and physical limitations of their condition prevented them from doing so. In this vein, and seemingly based on their perceptions of what makes a 'good' significant other, significant others acted as a 'witness to pain', supporting claimants' self-limiting behaviour and statements of incapacity, often responding with empathy and assistance. The beliefs and responses of significant others may also have been influenced by their own experience of chronic illness, thus participants lives were often intertwined and defined by illness.
Conclusions
The findings from this exploratory study reveal how others and wider social circumstances might contribute both to the propensity of persistent back pain and to its consequences. This is an area that has received little attention to date, and wider support of these findings may usefully inform the design of future intervention programmes aimed at restoring work participation
Comparison between resistive and collisionless double tearing modes for nearby resonant surfaces
The linear instability and nonlinear dynamics of collisional (resistive) and
collisionless (due to electron inertia) double tearing modes (DTMs) are
compared with the use of a reduced cylindrical model of a tokamak plasma. We
focus on cases where two q = 2 resonant surfaces are located a small distance
apart. It is found that regardless of the magnetic reconnection mechanism,
resistivity or electron inertia, the fastest growing linear eigenmodes may have
high poloidal mode numbers m ~ 10. The spectrum of unstable modes tends to be
broader in the collisionless case. In the nonlinear regime, it is shown that in
both cases fast growing high-m DTMs lead to an annular collapse involving small
magnetic island structures. In addition, collisionless DTMs exhibit multiple
reconnection cycles due to reversibility of collisionless reconnection and
strong ExB flows. Collisionless reconnection leads to a saturated stable state,
while in the collisional case resistive decay keeps the system weakly dynamic
by driving it back towards the unstable equilibrium maintained by a source
term.Comment: 15 pages, 9 figure
Genomic catastrophes frequently arise in esophageal adenocarcinoma and drive tumorigenesis
Oesophageal adenocarcinoma (EAC) incidence is rapidly increasing in Western countries. A better understanding of EAC underpins efforts to improve early detection and treatment outcomes. While large EAC exome sequencing efforts to date have found recurrent loss-offunction mutations, oncogenic driving events have been underrepresented. Here we use a combination of whole-genome sequencing (WGS) and single-nucleotide polymorphism-array profiling to show that genomic catastrophes are frequent in EAC, with almost a third (32%, nŒ40/123) undergoing chromothriptic events. WGS of 22 EAC cases show that catastrophes may lead to oncogene amplification through chromothripsis-derived double-minute chromosome formation (MYC and MDM2) or breakage-fusion-bridge (KRAS, MDM2 and RFC3). Telomere shortening is more prominent in EACs bearing localized complex rearrangements. Mutational signature analysis also confirms that extreme genomic instability in EAC can be driven by somatic BRCA2 mutations. These findings suggest that genomic catastrophes have a significant role in the malignant transformation of EAC
- âŠ