1,077 research outputs found
On Measure Transformed Canonical Correlation Analysis
In this paper linear canonical correlation analysis (LCCA) is generalized by
applying a structured transform to the joint probability distribution of the
considered pair of random vectors, i.e., a transformation of the joint
probability measure defined on their joint observation space. This framework,
called measure transformed canonical correlation analysis (MTCCA), applies LCCA
to the data after transformation of the joint probability measure. We show that
judicious choice of the transform leads to a modified canonical correlation
analysis, which, in contrast to LCCA, is capable of detecting non-linear
relationships between the considered pair of random vectors. Unlike kernel
canonical correlation analysis, where the transformation is applied to the
random vectors, in MTCCA the transformation is applied to their joint
probability distribution. This results in performance advantages and reduced
implementation complexity. The proposed approach is illustrated for graphical
model selection in simulated data having non-linear dependencies, and for
measuring long-term associations between companies traded in the NASDAQ and
NYSE stock markets
Robust Multiple Signal Classification via Probability Measure Transformation
In this paper, we introduce a new framework for robust multiple signal
classification (MUSIC). The proposed framework, called robust
measure-transformed (MT) MUSIC, is based on applying a transform to the
probability distribution of the received signals, i.e., transformation of the
probability measure defined on the observation space. In robust MT-MUSIC, the
sample covariance is replaced by the empirical MT-covariance. By judicious
choice of the transform we show that: 1) the resulting empirical MT-covariance
is B-robust, with bounded influence function that takes negligible values for
large norm outliers, and 2) under the assumption of spherically contoured noise
distribution, the noise subspace can be determined from the eigendecomposition
of the MT-covariance. Furthermore, we derive a new robust measure-transformed
minimum description length (MDL) criterion for estimating the number of
signals, and extend the MT-MUSIC framework to the case of coherent signals. The
proposed approach is illustrated in simulation examples that show its
advantages as compared to other robust MUSIC and MDL generalizations
Biomechanics in Surgical Mesh Fixation for Abdominal Wall Repair.
Surgical mesh fixation during abdominal wall repair has generally relied on sutures, staples and different kinds of tackling devices in traditional surgical procedures. However, conventional fixati..
Helicobacter pylori and pregnancy-related disorders.
Helicobacter pylori (H. pylori) infection is investigated in gastric diseases even during pregnancy. In particular, this Gram-negative bacterium seems to be associated with hyperemesis gravidarum, a severe form of nausea and vomiting during pregnancy. During the last decade, the relationship among H. pylori and several extra-gastric diseases strongly emerged in literature. The correlation among H. pylori infection and pregnancy-related disorders was mainly focused on iron deficiency anemia, thrombocytopenia, fetal malformations, miscarriage, pre-eclampsia and fetal growth restriction. H. pylori infection may have a role in the pathogenesis of various pregnancy-related disorders through different mechanisms: depletion of micronutrients (iron and vitamin B(12)) in maternal anemia and fetal neural tube defects; local or systemic induction of pro-inflammatory cytokines release and oxidative stress in gastrointestinal disorders and pre-eclampsia; cross-reaction between specific anti-H. pylori antibodies and antigens localized in placental tissue and endothelial cells (pre-eclampsia, fetal growth restriction, miscarriage). Since H. pylori infection is most likely acquired before pregnancy, it is widely believed that hormonal and immunological changes occurring during pregnancy could activate latent H. pylori with a negative impact not only on maternal health (nutritional deficiency, organ injury, death), but also on the fetus (insufficient growth, malformation, death) and sometime consequences can be observed later in life. Another important issue addressed by investigators was to determine whether it is possible to transmit H. pylori infection from mother to child and whether maternal anti-H. pylori antibodies could prevent infant’s infection. Studies on novel diagnostic and therapeutic methods for H. pylori are no less important, since these are particularly sensitive topics in pregnancy conditions. It could be interesting to study the possible correlation between H. pylori infection and other pregnancy-related diseases of unknown etiology, such as gestational diabetes mellitus, obstetric cholestasis and spontaneous preterm delivery. Since H. pylori infection is treatable, the demonstration of its causative role in pregnancy-related disorders will have important social-economic implications
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