160 research outputs found
The mesopancreas is the primary site for R1 resection in pancreatic head cancer: relevance for clinical trials
Evolutionary discriminative confidence estimation for spoken term detection
The final publication is available at Springer via http://dx.doi.org/10.1007/s11042-011-0913-zSpoken term detection (STD) is the task of searching for occurrences
of spoken terms in audio archives. It relies on robust confidence estimation
to make a hit/false alarm (FA) decision. In order to optimize the decision
in terms of the STD evaluation metric, the confidence has to be discriminative.
Multi-layer perceptrons (MLPs) and support vector machines (SVMs) exhibit
good performance in producing discriminative confidence; however they are
severely limited by the continuous objective functions, and are therefore less
capable of dealing with complex decision tasks. This leads to a substantial
performance reduction when measuring detection of out-of-vocabulary (OOV)
terms, where the high diversity in term properties usually leads to a complicated
decision boundary.
In this paper we present a new discriminative confidence estimation approach
based on evolutionary discriminant analysis (EDA). Unlike MLPs and
SVMs, EDA uses the classification error as its objective function, resulting
in a model optimized towards the evaluation metric. In addition, EDA combines
heterogeneous projection functions and classification strategies in decision
making, leading to a highly flexible classifier that is capable of dealing
with complex decision tasks. Finally, the evolutionary strategy of EDA reduces the risk of local minima. We tested the EDA-based confidence with a
state-of-the-art phoneme-based STD system on an English meeting domain
corpus, which employs a phoneme speech recognition system to produce lattices
within which the phoneme sequences corresponding to the enquiry terms
are searched. The test corpora comprise 11 hours of speech data recorded with
individual head-mounted microphones from 30 meetings carried out at several
institutes including ICSI; NIST; ISL; LDC; the Virginia Polytechnic Institute
and State University; and the University of Edinburgh. The experimental results
demonstrate that EDA considerably outperforms MLPs and SVMs on
both classification and confidence measurement in STD, and the advantage
is found to be more significant on OOV terms than on in-vocabulary (INV)
terms. In terms of classification performance, EDA achieved an equal error
rate (EER) of 11% on OOV terms, compared to 34% and 31% with MLPs and
SVMs respectively; for INV terms, an EER of 15% was obtained with EDA
compared to 17% obtained with MLPs and SVMs. In terms of STD performance
for OOV terms, EDA presented a significant relative improvement of
1.4% and 2.5% in terms of average term-weighted value (ATWV) over MLPs
and SVMs respectively.This work was partially supported by the French Ministry of Industry
(Innovative Web call) under contract 09.2.93.0966, âCollaborative Annotation for Video
Accessibilityâ (ACAV) and by âThe Adaptable Ambient Living Assistantâ (ALIAS) project
funded through the joint national Ambient Assisted Living (AAL) programme
Calibrated Sub-Bundles in Non-Compact Manifolds of Special Holonomy
This paper is a continuation of math.DG/0408005. We first construct special
Lagrangian submanifolds of the Ricci-flat Stenzel metric (of holonomy SU(n)) on
the cotangent bundle of S^n by looking at the conormal bundle of appropriate
submanifolds of S^n. We find that the condition for the conormal bundle to be
special Lagrangian is the same as that discovered by Harvey-Lawson for
submanifolds in R^n in their pioneering paper. We also construct calibrated
submanifolds in complete metrics with special holonomy G_2 and Spin(7)
discovered by Bryant and Salamon on the total spaces of appropriate bundles
over self-dual Einstein four manifolds. The submanifolds are constructed as
certain subbundles over immersed surfaces. We show that this construction
requires the surface to be minimal in the associative and Cayley cases, and to
be (properly oriented) real isotropic in the coassociative case. We also make
some remarks about using these constructions as a possible local model for the
intersection of compact calibrated submanifolds in a compact manifold with
special holonomy.Comment: 20 pages; for Revised Version: Minor cosmetic changes, some
paragraphs rewritten for improved clarit
Coherent X-ray Diffractive Imaging; applications and limitations
The inversion of a diffraction pattern offers aberration-free
diffraction-limited 3D images without the resolution and depth-of-field
limitations of lens-based tomographic systems, the only limitation being
radiation damage. We review our experimental results, discuss the fundamental
limits of this technique and future plans.Comment: 7 pages, 8 figure
Electron detachment from negative ions in bichromatic laser field
Negative ion detachment in two-colour laser field is considered within the
recent modification of Keldysh model which makes it quantitatively reliable.
The general approach is illustrated by calculation of angular differential
detachment rates, partial rates for particular ATD (Above Threshold Detachment)
channels and total detachment rates for H ion in bichromatic field with 1:2
frequency ratio. Both perturbative and strong field regimes are examined. Polar
asymmetry and phase effects are quantitatively characterized with some new
features revealed. Phase effects are found to result in a huge anisotropy
factor in the electron angular distribution in the perturbative
regime.Comment: 13 pages, 8 figures in separate files which are not incorporated in
the latex file of the pape
Prognostic significance of endogenous adhesion/growth-regulatory lectins in lung cancer
Objective: To determine the expression of endogenous adhesion/growth-regulatory lectins and their binding sites using labeled tissue lectins as well as the binding profile of hyaluronic acid as an approach to define new prognostic markers. Methods: Sections of paraffin-embedded histological material of 481 lungs from lung tumor patients following radical lung excision processed by a routine immunohistochemical method (avidin-biotin labeling, DAB chromogen). Specific antibodies against galectins-1 and - 3 and the heparin-binding lectin were tested. Staining by labeled galectins and hyaluronic acid was similarly visualized by a routine protocol. After semiquantitative assessment of staining, the results were compared with the pT and pN stages and the histological type. Survival was calculated by univariate and multivariate methods. Results: Binding of galectin-1 and its expression tended to increase, whereas the parameters for galectin-3 decreased in advanced pT and pN stages at a statistically significant level. The number of positive cases was considerably smaller among the cases with small cell lung cancer than in the group with non-small-cell lung cancer, among which adenocarcinomas figured prominently with the exception of galectin-1 expression. Kaplan-Meier computations revealed that the survival rate of patients with galectin-3-binding or galectin-1-expressing tumors was significantly poorer than that of the negative cases. In the multivariate calculations of survival lymph node metastases ( p < 0.0001), histological type ( p = 0.003), galectin-3-binding capacity ( p = 0.01), galectin-3 expression ( p = 0.03) and pT status ( p = 0.003) proved to be independent prognostic factors, not correlated with the pN stage. Conclusion: The expression and the capacity to bind the adhesion/growth regulatory galectin-3 is defined as an unfavorable prognostic factor not correlated with the pTN stage. Copyright (C) 2005 S. Karger AG, Basel
LEED Holography applied to a complex superstructure: a direct view of the adatom cluster on SiC(111)-(3x3)
For the example of the SiC(111)-(3x3) reconstruction we show that a
holographic interpretation of discrete Low Energy Electron Diffraction (LEED)
spot intensities arising from ordered, large unit cell superstructures can give
direct access to the local geometry of a cluster around an elevated atom,
provided there is only one such prominent atom per surface unit cell. By
comparing the holographic images obtained from experimental and calculated data
we illuminate validity, current limits and possible shortcomings of the method.
In particular, we show that periodic vacancies such as cornerholes may inhibit
the correct detection of the atomic positions. By contrast, the extra
diffraction intensity due to slight substrate reconstructions, as for example
buckling, seems to have negligible influence on the images. Due to the spatial
information depth of the method the stacking of the cluster can be imaged down
to the fourth layer. Finally, it is demonstrated how this structural knowledge
of the adcluster geometry can be used to guide the dynamical intensity analysis
subsequent to the holographic reconstruction and necessary to retrieve the full
unit cell structure.Comment: 11 pages RevTex, 6 figures, Phys. Rev. B in pres
Adiabatic Theory of Electron Detachment from Negative Ions in Two-Color Laser Field
Negative ion detachment in bichromatic laser field is considered within the
adiabatic theory. The latter represents a recent modification of the famous
Keldysh model for multiphoton ionization which makes it quantitatively
reliable. We calculate angular differential detachment rates, partial rates for
particular ATD (Above Threshold Detachment) channels and total detachment rates
for the Hydrogen ion in a bichromatic field with 1:3 frequency ratio and
various phase differences. Reliability of the present, extremely simple
approach is testified by comparison with much more elaborate earlier
calculations.Comment: 22 pages, 6 Postscript figure
The diagnosis and management of patients with idiopathic osteolysis
Idiopathic osteolysis or disappearing bone disease is a condition characterized by the spontaneous onset of rapid destruction and resorption of a single bone or multiple bones. Disappearing bone disorder is a disease of several diagnostic types. We are presenting three patients with osteolysis who have different underlying pathological features. Detailed phenotypic assessment, radiologic and CT scanning, and histological and genetic testing were the baseline diagnostic tools utilized for diagnosis of each osteolysis syndrome. The first patient was found to have Gorham-Stout syndrome (non-heritable). The complete destruction of pelvic bones associated with aggressive upward extension to adjacent bones (vertebral column and skull base) was notable and skeletal angiomatosis was detected. The second patient showed severe and aggressive non-hereditary multicentric osteolysis with bilateral destruction of the hip bones and the tarsal bones as well as a congenital unilateral solitary kidney and nephropathy. The third patient was phenotypically and genotypically compatible with Winchester syndrome resulting in multicentric osteolysis (autosomal recessive). Proven mutation of the (MMP2-Gen) was detected in this third patient that was associated with 3MCC deficiency (3-Methylcrontonyl CoA Carboxylase deficiency). The correct diagnoses in our 3 patients required the exclusion of malignant osteoclastic tumours, inflammatory disorders of bone, vascular disease, and neurogenic arthropathies using history, physical exam, and appropriate testing and imaging. This review demonstrates how to evaluate and treat these complex and difficult patients. Lastly, we described the various management procedures and treatments utilized for these patients
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