186,400 research outputs found
Analysis of incidence, mortality and survival for pancreatic and biliary tract cancers across Europe, with assessment of influence of revised European age standardisation on estimates
No full textBackground: Pancreatic (PC) and biliary tract (BTC) cancers have higher incidence and mortality in Europe than elsewhere. We analysed time-trends in PC/BTC incidence, mortality, and survival across Europe. Since the European standard population (ESP) was recently revised to better represent European age structure, we also assessed the effect of adopting the revised ESP to age-standardise incidence and mortality data. Methods: We analysed PCs/BTCs (≥15 years) diagnosed in 2000–2007 and followed-up to end of 2008, in 29 European countries across five regions: UK/Ireland, and northern, central, southern, and eastern Europe. Incidence, mortality, and 5-year relative survival were compared between regions, by age, sex, and period of diagnosis. Results: Variation in age-standardised incidence (PC 12–15/100,000; BTC 2–6) and mortality (PC 10–14; BTC 1–5) was modest. Eastern Europe had highest incidence and mortality, and lowest survival; northern and southern Europe had highest age-specific incidence (most age groups) for PC and BTC, respectively. Incidence and survival increased slightly from 2000 to 2007, particularly in elderly patients and women, but survival remained poor (≤8% for PC; 13–18% for BTC). Use of the revised ESP for age-standardisation did not impact European regional incidence and mortality rankings. Conclusion: Poor survival for PC and BTC, together with increasing incidence, indicate that action is required. Countries with higher incidence had higher risk factor frequency, suggesting that prevention initiatives targeting risk factors should be promoted. Improvements in diagnosis and treatment are also required. Our results provide a baseline from which to monitor evolution of the PC/BTC burden in Europe
Relative and disease-free survival for breast cancer in relation to subtype: a population-based study
No full textRegularity of the Level Set Flow
No full textWe showed earlier that the level set function of a monotonic advancing front is twice differentiable everywhere with bounded second derivative and satisfies the equation classically. We show here that the second derivative is continuous if and only if the flow has a single singular time where it becomes extinct and the singular set consists of a closed C[superscript 1] manifold with cylindrical singularities. © 2017 Wiley Periodicals, Inc.National Science Foundation (U.S.) (Grant DMS 1404540)National Science Foundation (U.S.) (Grant DMS 1206827
A Colding-Minicozzi stability inequality and its applications
No full textWe consider operators
L
L
acting on functions on a Riemannian surface,
Σ
\Sigma
, of the form
Here
Δ
\Delta
is the Laplacian of
Σ
\Sigma
,
V
V
a nonnegative potential on
Σ
\Sigma
,
K
K
the Gaussian curvature and
a
a
is a nonnegative constant.
Such operators
L
L
arise as the stability operator of
Σ
\Sigma
immersed in a Riemannian
3
−
3-
manifold with constant mean curvature (for particular choices of
V
V
and
a
a
). We assume that
L
L
is nonpositive acting on functions compactly supported on
Σ
\Sigma
and we obtain results in the spirit of some theorems of Fischer-Colbrie-Schoen, Colding-Minicozzi and Castillon. We extend these theorems to
a
≤
1
/
4
a \leq 1/4
. We obtain results on the conformal type of
Σ
\Sigma
and a distance (to the boundary) lemma.</p
Lower bounds for nodal sets of eigenfunctions
No full textWe prove lower bounds for the Hausdorff measure of nodal sets of eigenfunctions.National Science Foundation (U.S.) (Grant DMS 0606629)National Science Foundation (U.S.) (Grant DMS 0906233)National Science Foundation (U.S.). Focused Research Group (grant DMS 0854774)National Science Foundation (U.S.). Focused Research Group (grant DMS 0853501
Intra-thoracic desmoid tumour in a patient with a previous aortocoronary bypass
No full textAbstract Background Intra-thoracic desmoid tumours with mediastinal invasion are very rare. Although rare they have to be taken into account in the differential diagnosis of a thoracic mass and therapeutic options have to be weighted since surgical treatment may require wide excision. Case presentation A 48-year-old male diabetic, dyslipidaemic, former heavy smoker with psychiatric illness was operated by sternotomy for a triple aorto-coronary bypass 4 years before, presented with complains of recent onset such as constant and oppressive chest pain. At surgery a mass extending from the aortic arch into the entire anterior mediastinum and to most of the right pleural cavity was found. The mass was separated from sternal periosteum and vessels of aorto-coronary by pass were isolated starting from the aortic arch up to the pericardium. The histological examination revealed aggressive fibromatosis. Conclusion Although technically demanding, radical surgical excision is actually the most indicated therapeutic approach for intra-thoracic desmoid tumours.</p
The singular set of mean curvature flow with generic singularities
No full textA mean curvature flow starting from a closed embedded hypersurface in R[superscript n+1] must develop singularities. We show that if the flow has only generic singularities, then the space-time singular set is contained in finitely many compact embedded (n−1)-dimensional Lipschitz submanifolds plus a set of dimension at most n−2. If the initial hypersurface is mean convex, then all singularities are generic and the results apply. In R³ and R[superscript 4], we show that for almost all times the evolving hypersurface is completely smooth and any connected component of the singular set is entirely contained in a time-slice. For 2 or 3-convex hypersurfaces in all dimensions, the same arguments lead to the same conclusion: the flow is completely smooth at almost all times and connected components of the singular set are contained in time-slices. A key technical point is a strong parabolic Reifenberg property that we show in all dimensions and for all flows with only generic singularities. We also show that the entire flow clears out very rapidly after a generic singularity. These results are essentially optimal.National Science Foundation (U.S.). (Grants DMS 1404540, DMS 11040934, DMS 1206827)National Science Foundation (U.S.). Focused Research Group (Grants DMS 0854774 and DMS 0853501
On uniqueness of tangent cones for Einstein manifolds
No full textWe show that for any Ricci-flat manifold with Euclidean volume growth the tangent cone at infinity is unique if one tangent cone has a smooth cross-section. Similarly, for any noncollapsing limit of Einstein manifolds with uniformly bounded Einstein constants, we show that local tangent cones are unique if one tangent cone has a smooth cross-section.National Science Foundation (U.S.) (NSF Grant DMS 0906233)National Science Foundation (U.S.) (NSF Grant DMS 11040934)National Science Foundation (U.S.) (NSF FRG grant DMS 0853501)National Science Foundation (U.S.) (NSF FRG grant DMS 0854774
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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