934 research outputs found
Effect of leaf temperature on estimating physiological traits of wheat leaves from hyperspectral reflectance
A growing number of leaf traits can be predicted from hyperspectral reflectance data. These include structural and compositional traits, such as leaf mass per area, nitrogen and chlorophyll content, but also physiological traits such a Rubisco carboxylation activity, electron transport rate and respiration rate. Since physiological traits vary with leaf temperature, how does this impact on predictions made from reflectance measurements? We investigated this with two wheat varieties, by repeatedly measuring each leaf through a sequence of temperatures imposed by varying the air temperature in a growth room. The function predicting Rubisco capacity normalised to 25 °C predicted the same value, regardless of leaf temperatures ranging from 20 to 35°C. Leaf temperature affected none of the predicted traits: Vcmax25, J, chlorophyll content, LMA, N content per unit leaf area or Vcmax25/N. However, as others have derived models to predict Rubisco activity that includes variation associated with leaf temperature, we discuss whether these functions may include a temperature signal within the reflectance spectra
A pilot randomised controlled trial of personalised care after treatment for prostate cancer (TOPCAT-P): nurse-led holistic-needs assessment and individualised psychoeducational intervention: study protocol
INTRODUCTION. Prostate cancer is common and the incidence is increasing, but more men are living longer after diagnosis, and die with their disease rather than of it. Nonetheless, specific and substantial physical, sexual, emotional and mental health problems often lead to a poor quality of life. Urology services increasingly struggle to cope with the demands of follow-up care, and primary care is likely to play the central role in long-term follow-up. The present phase II trial will evaluate the feasibility and acceptability of a nurse-led, person-centred psychoeducational intervention, delivered in community or primary care settings.
METHODS AND ANALYSIS. Prostate cancer survivors diagnosed in the past 9-48 months and currently biochemically stable will be identified from hospital records by their treating clinician. Eligible men would have either completed radical treatment, or would be followed up with prostate specific antigen monitoring and symptom reporting. We will recruit 120 patients who will be randomised to receive either an augmented form of usual care, or an additional nurse-led intervention for a period of 36 weeks. Following the health policy in Wales, the intervention is offered by a key worker, is promoting prudent healthcare and is using a holistic needs assessment. Outcome measures will assess physical symptoms, psychological well-being, confidence in managing own health and quality of life. Healthcare service use will be measured over 36 weeks. Feedback interviews with patients and clinicians will further inform the acceptability of the intervention. Recruitment, attrition, questionnaire completion rates and outcome measures variability will be assessed, and results will inform the design of a future phase III trial and accompanying economic evaluation.
ETHICS AND DISSEMINATION. Ethics approval was granted by Bangor University and North Wales REC (13/WA/0291). Results will be reported in peer-reviewed publications, at scientific conferences, and directly through national cancer and primary care networks.
TRIAL REGISTRATION NUMBER. ISRCTN 34516019
Finite-Element Discretization of Static Hamilton-Jacobi Equations Based on a Local Variational Principle
We propose a linear finite-element discretization of Dirichlet problems for
static Hamilton-Jacobi equations on unstructured triangulations. The
discretization is based on simplified localized Dirichlet problems that are
solved by a local variational principle. It generalizes several approaches
known in the literature and allows for a simple and transparent convergence
theory. In this paper the resulting system of nonlinear equations is solved by
an adaptive Gauss-Seidel iteration that is easily implemented and quite
effective as a couple of numerical experiments show.Comment: 19 page
Hardy's inequality and curvature
A Hardy inequality of the form \int_{\tilde{\Omega}} |\nabla f({\bf{x}})|^p
d {\bf{x}} \ge (\frac{p-1}{p})^p \int_{\tilde{\Omega}} \{1 + a(\delta, \partial
\tilde{\Omega})(\x)\}\frac{|f({\bf{x}})|^p}{\delta({\bf{x}})^p} d{\bf{x}},
for all , is considered for , where can be either or with a domain in , , and
is the distance from to the
boundary The main emphasis is on determining the
dependance of on the geometric
properties of A Hardy inequality is also
established for any doubly connected domain in in terms
of a uniformisation of that is, any conformal univalent map of
onto an annulus
Exact Hypersurface-Homogeneous Solutions in Cosmology and Astrophysics
A framework is introduced which explains the existence and similarities of
most exact solutions of the Einstein equations with a wide range of sources for
the class of hypersurface-homogeneous spacetimes which admit a Hamiltonian
formulation. This class includes the spatially homogeneous cosmological models
and the astrophysically interesting static spherically symmetric models as well
as the stationary cylindrically symmetric models. The framework involves
methods for finding and exploiting hidden symmetries and invariant submanifolds
of the Hamiltonian formulation of the field equations. It unifies, simplifies
and extends most known work on hypersurface-homogeneous exact solutions. It is
shown that the same framework is also relevant to gravitational theories with a
similar structure, like Brans-Dicke or higher-dimensional theories.Comment: 41 pages, REVTEX/LaTeX 2.09 file (don't use LaTeX2e !!!) Accepted for
publication in Phys. Rev.
Tight Beltrami fields with symmetry
Let be a compact orientable Seifered fibered 3-manifold without a
boundary, and an -invariant contact form on . In a suitable
adapted Riemannian metric to , we provide a bound for the volume
and the curvature, which implies the universal tightness of the
contact structure .Comment: 26 page
A nonhomogeneous boundary value problem in mass transfer theory
We prove a uniqueness result of solutions for a system of PDEs of
Monge-Kantorovich type arising in problems of mass transfer theory. The results
are obtained under very mild regularity assumptions both on the reference set
, and on the (possibly asymmetric) norm defined in
. In the special case when is endowed with the Euclidean
metric, our results provide a complete description of the stationary solutions
to the tray table problem in granular matter theory.Comment: 22 pages, 2 figure
Classification of minimal actions of a compact Kac algebra with amenable dual
We show the uniqueness of minimal actions of a compact Kac algebra with
amenable dual on the AFD factor of type II. This particularly implies the
uniqueness of minimal actions of a compact group. Our main tools are a Rohlin
type theorem, the 2-cohomology vanishing theorem, and the Evans-Kishimoto type
intertwining argument.Comment: 68 pages, Introduction rewritten; minor correction
Sharp Trace Hardy-Sobolev-Maz'ya Inequalities and the Fractional Laplacian
In this work we establish trace Hardy and trace Hardy-Sobolev-Maz'ya
inequalities with best Hardy constants, for domains satisfying suitable
geometric assumptions such as mean convexity or convexity. We then use them to
produce fractional Hardy-Sobolev-Maz'ya inequalities with best Hardy constants
for various fractional Laplacians. In the case where the domain is the half
space our results cover the full range of the exponent of the
fractional Laplacians. We answer in particular an open problem raised by Frank
and Seiringer \cite{FS}.Comment: 42 page
A Novel Method for High-Dimensional Anatomical Mapping of Extra-Axial Cerebrospinal Fluid: Application to the Infant Brain
Cerebrospinal fluid (CSF) plays an essential role in early postnatal brain development. Extra-axial CSF (EA-CSF) volume, which is characterized by CSF in the subarachnoid space surrounding the brain, is a promising marker in the early detection of young children at risk for neurodevelopmental disorders. Previous studies have focused on global EA-CSF volume across the entire dorsal extent of the brain, and not regionally-specific EA-CSF measurements, because no tools were previously available for extracting local EA-CSF measures suitable for localized cortical surface analysis. In this paper, we propose a novel framework for the localized, cortical surface-based analysis of EA-CSF. The proposed processing framework combines probabilistic brain tissue segmentation, cortical surface reconstruction, and streamline-based local EA-CSF quantification. The quantitative analysis of local EA-CSF was applied to a dataset of typically developing infants with longitudinal MRI scans from 6 to 24 months of age. There was a high degree of consistency in the spatial patterns of local EA-CSF across age using the proposed methods. Statistical analysis of local EA-CSF revealed several novel findings: several regions of the cerebral cortex showed reductions in EA-CSF from 6 to 24 months of age, and specific regions showed higher local EA-CSF in males compared to females. These age-, sex-, and anatomically-specific patterns of local EA-CSF would not have been observed if only a global EA-CSF measure were utilized. The proposed methods are integrated into a freely available, open-source, cross-platform, user-friendly software tool, allowing neuroimaging labs to quantify local extra-axial CSF in their neuroimaging studies to investigate its role in typical and atypical brain development
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