110 research outputs found
A Near-Neighbor Statistical Survey of the Environments of Galaxies with Water Masers
Water mega-masers provide crucial tools for accurate determination ofmasses of black holes lurking in galaxy centers, and of extragalacticdistances without the need for indirect cosmological assumptions. Current searches have detected masers in only 3 - 4% of the galaxies surveyed and require refinement of their survey criteria. Motivated by current models linking galaxy environment and black hole accretion and the possibility that maser activity correlates with black hole accretion, we conducted a study of the properties of the small and large-scale environments of galaxies hosting masers. Using samples of galaxies with and without maser detections provided by the Megamaser Cosmology Project, together with the Sloan Digital Sky Survey spectroscopic observations, we present a comparative analysis of near-neighbor statistics and their properties, which include distances to the n-th neighbors as well as neighbor counts within fixed volumes, and optical colors and absolute brightness distributions. We show evidence that the environments of the mega-masers in particular differ from those of galaxies where maser activity was not detected, with the mega-masers possiblyprefering the lower density regions. Nevertheless, the trends presented by various measures of the environmental properties of maser and non-maser systems remain complicated. A better understanding of the factors that closely connect with the masing conditions and overall activity can be achieved with higher number statistics, possibly through conducting near-neighbor investigations involving photometric redshift measurements, that allow characterization of neighboring systems at much fainter levels
The role of parasite-driven selection in shaping landscape genomic structure in red grouse (Lagopus lagopus scotica)
Acknowledgements This study was funded by a BBSRC studentship (MAW) and NERC grants NE/H00775X/1 and NE/D000602/1 (SBP). The authors are grateful to Mario Röder and Keliya Bai for fieldwork assistance, and all estate owners, factors and keepers for access to field sites, most particularly MJ Taylor and Mike Nisbet (Airlie), Neil Brown (Allargue), RR Gledson and David Scrimgeour (Delnadamph), Andrew Salvesen and John Hay (Dinnet), Stuart Young and Derek Calder (Edinglassie), Kirsty Donald and David Busfield (Glen Dye), Neil Hogbin and Ab Taylor (Glen Muick), Alistair Mitchell (Glenlivet), Simon Blackett, Jim Davidson and Liam Donald (Invercauld), Richard Cooke and Fred Taylor† (Invermark), Shaila Rao and Christopher Murphy (Mar Lodge), and Ralph Peters and Philip Astor (Tillypronie). S.B.P. and S.M.R. conceived and designed the study. M.A.W. performed field and laboratory work. A.D. and M.C.J. developed SNP markers. M.A.W. analysed the data. M.A.W. and S.B.P. wrote the manuscript.Peer reviewedPostprin
Temporal trends and risk factors for readmission for infections, gastrointestinal and immobility complications after an incident hospitalisation for stroke in Scotland between 1997 and 2005
Background:
Improvements in stroke management have led to increases in the numbers of stroke survivors over the last decade and there has been a corresponding increase of hospital readmissions after an initial stroke hospitalisation. The aim of this study was to examine the one year risk of having a readmission due to infective, gastrointestinal or immobility (IGI) complications and to identify temporal trends and any risk factors.<p></p>
Methods:
Using a cohort of first hospitalised for stroke patients who were discharged alive, time to first event (readmission for IGI complications or death) within 1 year was analysed in a competing risks framework using cumulative incidence methods. Regression on the cumulative incidence function was used to model the risks of having an outcome using the covariates age, sex, socioeconomic status, comorbidity, discharge destination and length of hospital stay.<p></p>
Results:
There were a total of 51,182 patients discharged alive after an incident stroke hospitalisation in Scotland between 1997–2005, and 7,747 (15.1%) were readmitted for IGI complications within a year of the discharge. Comparing incident stroke hospitalisations in 2005 with 1997, the adjusted risk of IGI readmission did not increase (HR = 1.00 95% CI (0.90, 1.11). However, there was a higher risk of IGI readmission with increasing levels of deprivation (most deprived fifth vs. least deprived fifth HR = 1.16 (1.08, 1.26).<p></p>
Conclusions:
Approximately 15 in 100 patients discharged alive after an incident hospitalisation for stroke in Scotland between 1997 and 2005 went on to have an IGI readmission within one year. The proportion of readmissions did not change over the study period but those living in deprived areas had an increased risk
Coronary heart disease mortality among young adults in Scotland in relation to social inequalities: time trend study
Objective To examine recent trends and social inequalities in age specific coronary heart disease mortality
Remodelling of human atrial K+ currents but not ion channel expression by chronic β-blockade
Chronic β-adrenoceptor antagonist (β-blocker) treatment in patients is associated with a potentially anti-arrhythmic prolongation of the atrial action potential duration (APD), which may involve remodelling of repolarising K+ currents. The aim of this study was to investigate the effects of chronic β-blockade on transient outward, sustained and inward rectifier K+ currents (ITO, IKSUS and IK1) in human atrial myocytes and on the expression of underlying ion channel subunits. Ion currents were recorded from human right atrial isolated myocytes using the whole-cell-patch clamp technique. Tissue mRNA and protein levels were measured using real time RT-PCR and Western blotting. Chronic β-blockade was associated with a 41% reduction in ITO density: 9.3 ± 0.8 (30 myocytes, 15 patients) vs 15.7 ± 1.1 pA/pF (32, 14), p < 0.05; without affecting its voltage-, time- or rate dependence. IK1 was reduced by 34% at −120 mV (p < 0.05). Neither IKSUS, nor its increase by acute β-stimulation with isoprenaline, was affected by chronic β-blockade. Mathematical modelling suggested that the combination of ITO- and IK1-decrease could result in a 28% increase in APD90. Chronic β-blockade did not alter mRNA or protein expression of the ITO pore-forming subunit, Kv4.3, or mRNA expression of the accessory subunits KChIP2, KChAP, Kvβ1, Kvβ2 or frequenin. There was no reduction in mRNA expression of Kir2.1 or TWIK to account for the reduction in IK1. A reduction in atrial ITO and IK1 associated with chronic β-blocker treatment in patients may contribute to the associated action potential prolongation, and this cannot be explained by a reduction in expression of associated ion channel subunits
Missing the peacock - arts, sciences, creativity, and chronic environmental conflicts
Debate on conflicts and disputes over environmental issues has intensified due to climate change and other global pressing problems becoming ever more pronounced. Simultaneously, there is little evidence of natural or social sciences helping transform even local conflicts, some of them lasting decades, gradually becoming chronic and having severe and pervasive effects on people’s lives. On the contrary, natural sciences often become part of the conflicts while social sciences remain distant observers. Conflict management requires creativity: imagining new solutions, relating to, thinking and acting in new ways. Hence, stimulation of creative thinking might offer avenues for coping with conflicting situations. We tested new forms of interaction and opportunities of creative work in managing prolonged conflicts in a series of meetings between natural scientists, social scientists, artists and conflict mediation professionals. This article discusses the experiences emerging from this experimental process. Experimenting with creative working methods provided us with new tools to facilitate interaction in the conflicts we intervene in or study. However, we don't see arts-science collaborations as a panacea to resolving conflict situations. More than interactive skills and tools that would lead to a clear-cut end of conflicts, we emphasize the ability to reflect on our own practice and role in environmental conflicts. Creative experiments can be valuable in pointing out open questions, such as what is the role that scientists, artists and mediators take and should take in controversial situations
Temporal trends in hospitalisation for stroke recurrence following incident hospitalisation for stroke in Scotland
<p>Background: There are few studies that have investigated temporal trends in risk of recurrent stroke. The aim of this study was to examine temporal trends in hospitalisation for stroke recurrence following incident hospitalisation for stroke in Scotland during 1986 to 2001.</p>
<p>Methods: Unadjusted survival analysis of time to first event, hospitalisation for recurrent stroke or death, was undertaken using the cumulative incidence method which takes into account competing risks. Regression on cumulative incidence functions was used to model the temporal trends of first recurrent stroke with adjustment for age, sex, socioeconomic status and comorbidity. Complete five year follow-up was obtained for all patients. Restricted cubic splines were used to determine the best fitting relationship between the survival events and study year.</p>
<p>Results: There were 128,511 incident hospitalisations for stroke in Scotland between 1986 and 2001, 57,351 (45%) in men. A total of 13,835 (10.8%) patients had a recurrent hospitalisation for stroke within five years of their incident hospitalisation. Another 74,220 (57.8%) patients died within five years of their incident hospitalisation without first having a recurrent hospitalisation for stroke. Comparing incident stroke hospitalisations in 2001 with 1986, the adjusted risk of recurrent stroke hospitalisation decreased by 27%, HR = 0.73 95% CI (0.67 to 0.78), and the adjusted risk of death being the first event decreased by 28%, HR = 0.72 (0.70 to 0.75).</p>
<p>Conclusions: Over the 15-year period approximately 1 in 10 patients with an incident hospitalisation for stroke in Scotland went on to have a hospitalisation for recurrent stroke within five years. Approximately 6 in 10 patients died within five years without first having a recurrent stroke hospitalisation. Using hospitalisation and death data from an entire country over a 20-year period we have been able to demonstrate not only an improvement in survival following an incident stroke, but also a reduction in the risk of a recurrent event.</p>
Differential protein phosphorylation in 3T3-L1 adipocytes in response to insulin versus platelet-derived growth factor
Insulin regulates glucose metabolism in adipocytes via a phosphatidylinositide 3-kinase (PI3K)-dependent pathway that appears to involve protein phosphorylation. However, the generation of phosphoinositides is not sufficient for insulin action, and it has been suggested that insulin regulation of glucose metabolism may involve both PI3K-dependent and -independent pathways, the latter being insulin specific. To test this hypothesis, we have designed a phosphoprotein screen to study insulin-specific phosphoproteins that may be either downstream or in parallel to PI3K. Nineteen insulin-regulated phosphospots were detected in the cytosol and high speed pellet fractions, only six of which were significantly regulated by platelet-derived growth factor. Importantly, almost all (92%) of the insulin-specific phosphoproteins identified using this approach were sensitive to the PI3K inhibitor wortmannin. Thus, we obtained no evidence for an insulin-specific, PI3K-independent signaling pathway. A large proportion (62%) of the insulin-specific phosphoproteins were enriched in the same high speed pellet fraction to which PI3K was recruited in response to insulin. Thus, our data suggest that insulin specifically stimulates the phosphorylation of a novel subset of downstream targets and this may in part be because of the unique localization of PI3K in response to insulin in adipocytes
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