7,095 research outputs found
Improving the health of people with multimorbidity: the need for prospective cohort studies
The dramatic rise in long-term conditions (LTCs) represents a major challenge for individuals, families, and health care systems worldwide. Due to the scale of this rise, the management of patients with LTCs largely falls within the domain of primary rather than secondary care, at least in countries with well-developed primary care systems. For example, in the UK, which has a comprehensive primary care system based around general practice (trained family physicians working in multidisciplinary teams) and funded by the National Health Service (NHS), primary care contacts account for around 90% of the total activity of the NHS, and patients with LTCs account for 80% of general practice consultations. Effective primary care and community-based management of people with LTCs is thus a top priority
Late-successional and old-growth forests in the northeastern United States: Structure, dynamics, and prospects for restoration.
Abstract
Restoration of old-growth forest structure is an emerging silvicultural goal, especially in those regions where old-growth abundance falls below the historic range of variability. However, longitudinal studies of old-growth dynamics that can inform silvicultural and policy options are few. We analyzed the change in structure, including stand density, diameter distribution, and the abundance of large live, standing dead, and downed dead trees on 58 late-successional and old-growth plots in Maine, USA, and compared these to regional data from the U.S. Forest Inventory and Analysis program. Structural dynamics on the late-successional plots reflected orderly change associated with density-dependent growth and mortality, but dynamics on the old-growth plots were more variable. Some plots experienced heavy mortality associated with beech bark disease. Diameter distributions conformed poorly to a classic exponential distribution, and did not converge toward such a distribution at the plot scale. Although large live trees showed a broad trend of increasing density in regional forests, recent harvesting patterns offset a considerable fraction of those gains, while mean diameter was static and the number of large dead trees was weakly declining. Even though forests of the northeast are aging, changes in silviculture and forest policy are necessary to accelerate restoration of old-growth structure
Combined Reconstruction and Registration of Digital Breast Tomosynthesis
Digital breast tomosynthesis (DBT) has the potential to en-
hance breast cancer detection by reducing the confounding e ect of su-
perimposed tissue associated with conventional mammography. In addi-
tion the increased volumetric information should enable temporal datasets
to be more accurately compared, a task that radiologists routinely apply
to conventional mammograms to detect the changes associated with ma-
lignancy. In this paper we address the problem of comparing DBT data
by combining reconstruction of a pair of temporal volumes with their reg-
istration. Using a simple test object, and DBT simulations from in vivo
breast compressions imaged using MRI, we demonstrate that this com-
bined reconstruction and registration approach produces improvements
in both the reconstructed volumes and the estimated transformation pa-
rameters when compared to performing the tasks sequentially
Couples as Partners and Parents over Children’s Early Years
We use data from the Fragile Families and Child Wellbeing Study to examine couple how couple relationship quality and parental engagement are linked over children’s early years. Our sample includes 1,630 couples that are co-resident over years 1 to 3 and 1,376 over years 3 to 5 (1,196 over both periods). Overall, we find that better relationship quality predicts greater parental engagement for both mothers and fathers—especially from children’s infant to toddler years; we find little evidence that parenting predicts future relationship quality. Married and cohabiting couples are generally similar in how relationship quality and parenting are linked. When couples are having their first birth, relationship quality is more strongly tied to parental engagement for fathers (but not mothers).Couple relationship quality, parenting, fragile families
How to design and evaluate interventions to improve outcomes for patients with multimorbidity
Multimorbidity is a major challenge for patients and healthcare providers. The limited evidence of the effectiveness of interventions for people with multimorbidity means that there is a need for much more research and trials of potential interventions. Here we present a consensus view from a group of international researchers working to improve care for people with multimorbidity to guide future studies of interventions. We suggest that there is a need for careful consideration of whom to include, how to target interventions that address specific problems and that do not add to treatment burden, and selecting outcomes that matter both to patients and the healthcare system. Innovative design of these interventions will be necessary as many will be introduced in service settings and it will be important to ensure methodological rigour, relevance to service delivery, and generalizability across healthcare systems
The evolution of clustering and bias in the galaxy distribution
This paper reviews the measurements of galaxy correlations at high redshifts,
and discusses how these may be understood in models of hierarchical
gravitational collapse. The clustering of galaxies at redshift one is much
weaker than at present, and this is consistent with the rate of growth of
structure expected in an open universe. If , this observation would
imply that bias increases at high redshift, in conflict with observed
values for known high- clusters. At redshift 3, the population of
Lyman-limit galaxies displays clustering which is of similar amplitude to that
seen today. This is most naturally understood if the Lyman-limit population is
a set of rare recently-formed objects. Knowing both the clustering and the
abundance of these objects, it is possible to deduce empirically the
fluctuation spectrum required on scales which cannot be measured today owing to
gravitational nonlinearities. Of existing physical models for the fluctuation
spectrum, the results are most closely matched by a low-density spatially flat
universe. This conclusion is reinforced by an empirical analysis of CMB
anisotropies, in which the present-day fluctuation spectrum is forced to have
the observed form. Open models are strongly disfavoured, leaving CDM
as the most successful simple model for structure formation.Comment: Invited review at the Royal Society Meeting `Large-scale structure in
the universe', London, March 1998. 20 Pages LaTe
Constraining Large Scale Structure Theories with the Cosmic Background Radiation
We review the relevant 10+ parameters associated with inflation and matter
content; the relation between LSS and primary and secondary CMB anisotropy
probes; COBE constraints on energy injection; current anisotropy band-powers
which strongly support the gravitational instability theory and suggest the
universe could not have reionized too early. We use Bayesian analysis methods
to determine what current CMB and CMB+LSS data imply for inflation-based
Gaussian fluctuations in tilted CDM, hCDM and oCDM model
sequences with age 11-15 Gyr, consisting of mixtures of baryons, cold (and
possibly hot) dark matter, vacuum energy, and curvature energy in open
cosmologies. For example, we find the slope of the initial spectrum is within
about 5% of the (preferred) scale invariant form when just the CMB data is
used, and for CDM when LSS data is combined with CMB; with both, a
nonzero value of is strongly preferred ( for a 13
Gyr sequence, similar to the value from SNIa). The CDM sequence prefers
, but is overall much less likely than the flat
sequence with CMB+LSS. We also review the rosy forecasts
of angular power spectra and parameter estimates from future balloon and
satellite experiments when foreground and systematic effects are ignored.Comment: 20 pages, LaTeX, 5 figures, 2 tables, uses rspublic.sty To appear in
Philosophical Transactions of the Royal Society of London A, 1998.
"Discussion Meeting on Large Scale Structure in the Universe," Royal Society,
London, March 1998. Text and colour figures also available at
ftp://ftp.cita.utoronto.ca/bond/roysoc9
Biogenic vs. geologic carbon emissions and forest biomass energy production
In the current debate over the CO2 emissions implications of switching from fossil fuel energy sources to include a substantial amount of woody biomass energy, many scientists and policy makers hold the view that emissions from the two sources should not be equated. Their rationale is that the combustion or decay of woody biomass is simply part of the global cycle of biogenic carbon and does not increase the amount of carbon in circulation. This view is frequently presented as justification to implement policies that encourage the substitution of fossil fuel energy sources with biomass. We present the opinion that this is an inappropriate conceptual basis to assess the atmospheric greenhouse gas (GHG) accounting of woody biomass energy generation. While there are many other environmental, social, and economic reasons to move to woody biomass energy, we argue that the inferred benefits of biogenic emissions over fossil fuel emissions should be reconsidered. © 2011 Blackwell Publishing Ltd
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