1,868 research outputs found
Are changes in breeding habitat responsible for recent population changes of long-distance migrant birds?
Capsule: The direction and magnitude of changes in structure of UK woodlands since the 1980s, are inconsistent with them playing a causative role in the declines of four migrant bird species in upland oak woods. /
Aims: To investigate whether changes in woodland structure were a possible cause of population changes of four Afro-Palearctic migrants (Wood Warbler Phylloscopus sibilatrix, Tree Pipit Anthus trivialis, Pied Flycatcher Ficedula hypoleuca and Common Redstart Phoenicurus phoenicurus) in the upland oakwoods of western and northern Britain. /
Methods: Bird population estimates and measures of woodland structure were recorded in two time periods 1982–85 and 2003–04 across six regions of the UK. We modelled the effect of habitat change and initial habitat state on population changes between the two time periods. The predicted effects of habitat change on populations were then compared with observed population changes across the different regions. /
Results: All four species underwent population declines; there were also significant increases in ground cover and understorey cover. The number of birds in 2003–04 was influenced by habitat structure at this time in addition to showing regional differences. Change in bird numbers varied between regions and was affected by both the initial habitat state and change in habitat structure, with regional variation in the effect of habitat change. There was however no relationship between the predicted effect of change in habitat structure on population size and observed regional population changes. /
Conclusions: Changes in woodland structure are unlikely to be the main driver of population change in these four migrant bird species, and large-scale factors affecting demographics in other parts of their breeding range or in their wintering areas are likely reasons for local population declines
Family preferences for home or hospital care at diagnosis for children with diabetes in the DECIDE study.
This is the final version of the article. Available from Wiley via the DOI in this record.AIMS: A diagnosis of Type 1 diabetes in childhood can be a difficult life event for children and families. For children who are not severely ill, initial home rather than hospital-based care at diagnosis is an option although there is little research on which is preferable. Practice varies widely, with long hospital stays in some countries and predominantly home-based care in others. This article reports on the comparative acceptability and experience of children with Type 1 diabetes and their parents taking part in the DECIDE study evaluating outcomes of home or hospital-based treatment from diagnosis in the UK. METHODS: Semi-structured interviews with 11 (pairs of) parents and seven children were conducted between 15 and 20 months post diagnosis. Interviewees were asked about adaptation to, management and impact of the diabetes diagnosis, and their experience of initial post-diagnosis treatment. RESULTS: There were no differences between trial arms in adaptation to, management of or impact of diabetes. Most interviewees wanted to be randomized to the 'home' arm initially but expressed a retrospective preference for whichever trial arm they had been in, and cited benefits relating to learning about diabetes management. CONCLUSIONS: The setting for early treatment did not appear to have a differential impact on families in the long term. However, the data presented here describe different experiences of early treatment settings from the perspective of children and their families, and factors that influenced how families felt initially about treatment setting. Further research could investigate the short-term benefits of both settings.National Institute for Social Care and Health Research Clinical Research Centr
Response to letter to editor: 'Comment on Arch et al., Trials. 2016;17:517'
In October 2015 we published the paper ‘Measurement of HbA1c in multicentre diabetes trials – should blood samples be tested locally or sent to a central laboratory: an agreement analysis’. Chatterjee and Pradhan have submitted a letter to the editor asking critical questions regarding the methods we used.
We offer this letter in response
Black Branes in a Box: Hydrodynamics, Stability, and Criticality
We study the effective hydrodynamics of neutral black branes enclosed in a
finite cylindrical cavity with Dirichlet boundary conditions. We focus on how
the Gregory-Laflamme instability changes as we vary the cavity radius R. Fixing
the metric at the cavity wall increases the rigidity of the black brane by
hindering gradients of the redshift on the wall. In the effective fluid, this
is reflected in the growth of the squared speed of sound. As a consequence,
when the cavity is smaller than a critical radius the black brane becomes
dynamically stable. The correlation with the change in thermodynamic stability
is transparent in our approach. We compute the bulk and shear viscosities of
the black brane and find that they do not run with R. We find mean-field theory
critical exponents near the critical point.Comment: 23 pages, 3 figures. v2: added comments on first-order phase
transitio
Generalized iterated wreath products of symmetric groups and generalized rooted trees correspondence
Consider the generalized iterated wreath product of symmetric groups. We give a complete description of the traversal
for the generalized iterated wreath product. We also prove an existence of a
bijection between the equivalence classes of ordinary irreducible
representations of the generalized iterated wreath product and orbits of labels
on certain rooted trees. We find a recursion for the number of these labels and
the degrees of irreducible representations of the generalized iterated wreath
product. Finally, we give rough upper bound estimates for fast Fourier
transforms.Comment: 18 pages, to appear in Advances in the Mathematical Sciences. arXiv
admin note: text overlap with arXiv:1409.060
Phase transitions and critical behavior of black branes in canonical ensemble
We study the thermodynamics and phase structure of asymptotically flat
non-dilatonic as well as dilatonic black branes in a cavity in arbitrary
dimensions (). We consider the canonical ensemble and so the charge inside
the cavity and the temperature at the wall are fixed. We analyze the stability
of the black brane equilibrium states and derive the phase structures. For the
zero charge case we find an analog of Hawking-Page phase transition for these
black branes in arbitrary dimensions. When the charge is non-zero, we find that
below a critical value of the charge, the phase diagram has a line of
first-order phase transition in a certain range of temperatures which ends up
at a second order phase transition point (critical point) as the charge attains
the critical value. We calculate the critical exponents at that critical point.
Although our discussion is mainly concerned with the non-dilatonic branes, we
show how it easily carries over to the dilatonic branes as well.Comment: 37 pages, 6 figures, the validity of using the effective action
discussed, references adde
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The influence of the atmospheric boundary layer on nocturnal layers of noctuids and other moths migrating over southern Britain
Insects migrating at high altitude over southern Britain have been continuously monitored by automatically-operating, vertical-looking radars over a period of several years. During some occasions in the summer months, the migrants were observed to form well-defined layer concentrations, typically at heights of 200-400 m, in the stable night-time atmosphere. Under these conditions, insects are likely to have control over their vertical movements and are selecting flight heights which are favourable for long-range migration. We therefore investigated the factors influencing the formation of these insect layers by comparing radar measurements of the vertical distribution of insect density with meteorological profiles generated by the UK Met. Office’s Unified Model (UM). Radar-derived measurements of mass and displacement speed, along with data from Rothamsted Insect Survey light traps provided information on the identity of the migrants. We present here three case studies where noctuid and pyralid moths contributed substantially to the observed layers. The major meteorological factors influencing the layer concentrations appeared to be: (a) the altitude of the warmest air, (b) heights corresponding to temperature preferences or thresholds for sustained migration and (c), on nights when air temperatures are relatively high, wind-speed maxima associated with the nocturnal jet. Back-trajectories indicated that layer duration may have been determined by the distance to the coast. Overall, the unique combination of meteorological data from the UM and insect data from entomological radar described here show considerable promise for systematic studies of high-altitude insect layering
Is metal theft committed by organized crime groups, and why does it matter?
Using the example of metal theft in the United Kingdom, this study used mixed methods to evaluate the accuracy of police estimates of the involvement of organised crime groups (OCGs) in crime. Police estimate that 20-30% of metal theft is committed by OCGs, but this study found that only 0.5% of metal thieves had previous convictions for offences related to OCGs, that only 1.3% were linked to OCGs by intelligence information, that metal thieves typically offended close to their homes and that almost no metal thefts involved sophisticated offence methods. It appears that police may over-estimate the involvement of OCGs in some types of crime. The reasons for and consequences of this over-estimation are discussed
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Small global-mean cooling due to volcanic radiative forcing
In both the observational record and atmosphere-ocean general circulation model (AOGCM) simulations of the last ∼∼ 150 years, short-lived negative radiative forcing due to volcanic aerosol, following explosive eruptions, causes sudden global-mean cooling of up to ∼∼ 0.3 K. This is about five times smaller than expected from the transient climate response parameter (TCRP, K of global-mean surface air temperature change per W m−2 of radiative forcing increase) evaluated under atmospheric CO2 concentration increasing at 1 % yr−1. Using the step model (Good et al. in Geophys Res Lett 38:L01703, 2011. doi:10.​1029/​2010GL045208), we confirm the previous finding (Held et al. in J Clim 23:2418–2427, 2010. doi:10.​1175/​2009JCLI3466.​1) that the main reason for the discrepancy is the damping of the response to short-lived forcing by the thermal inertia of the upper ocean. Although the step model includes this effect, it still overestimates the volcanic cooling simulated by AOGCMs by about 60 %. We show that this remaining discrepancy can be explained by the magnitude of the volcanic forcing, which may be smaller in AOGCMs (by 30 % for the HadCM3 AOGCM) than in off-line calculations that do not account for rapid cloud adjustment, and the climate sensitivity parameter, which may be smaller than for increasing CO2 (40 % smaller than for 4 × CO2 in HadCM3)
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