915 research outputs found
Mixed Mode Crack Propagation in Iliac Bone
Bone is a complex material that can be regarded as an anisotropic elastic composite material. The problem of crack propagation in hu- man bone is analyzed by using a generalization of the maximum tensile stress criterion (MTS). The results concern the critical stress for crack propagation and the direction of the crack path in Iliac bone
Improving Postdischarge Outcomes in Acute Heart Failure
The global burden that acute heart failure (AHF) carries has remained unchanged over the past several decades (1). European registries (2–5) showed that 1-year outcome rates remain unacceptably high (Table 1) and confirm that hospitalization for AHF represents a change in the natural history of the disease process(6). As patients hospitalized for HF have a bad prognosis, it is crucial to utilize hospitalization as an opportunity to: 1) assess the individual components of the cardiac substrate; 2) identify and treat comorbidities; 3) identify early, safe endpoints of therapy to facilitate timely hospital discharge and outpatient follow-up; and 4) implement and begin optimization guideline-directed medical therapies (GDMTs). As outcomes are influenced by many factors, many of which are incompletely understood, a systematic approach is proposed that should start with admission and continues through post-discharge (7)
Steady-state response feature extraction optimization to enhance electronic nose performance
Feature extraction of electronic nose (e-nose) output response aims to reduce information redundancy so that the e-nose performance can be improved. The use of different sensor types and sample targets can affect the optimization of feature extraction. This research used six types of metal oxide sensors, TGS 813, 822, 825, 826, 2620, and 2611 in an e-nose system to detect three types of herbal drink. Five kinds of feature extraction methods on the original response curve in a steady-state response were used, namely, baseline difference, logarithmic difference, local normalization, global normalization, and global autoscaling. The results of feature extraction were fed into a Principal Component Analysis (PCA) system. As a result, global autoscaling and normalization had the highest total sum of the first and second principal components of 96.96%, followed by local normalization (90.18%), logarithm, and baseline difference (88.92% and 79.26%, respectively). The validation of PCA results was performed using a Backpropagation Neural Network (BPNN). The highest accuracy, 97.44%, was obtained from the global autoscaling method, followed by global normalization, local normalization, logarithm, and baseline difference, with an accuracy level of 94.87%, 92.31%, 89.74%, and 82.05%, respectively. This demonstrates that the selection of the feature extraction method can affect the classification results and improve e-nose performance
The nature of phenotypic variation in Pavlovian conditioning
Pavlovian conditioning procedures result in dramatic individual differences in the topography of learnt behaviors in rats: When the temporary insertion of a lever into an operant chamber is paired with food pellets, some rats (known as sign-trackers) predominantly interact with the lever, while others (known as goal-trackers) predominantly approach the food well. Two experiments examined the sensitivity of these two behaviors to changing reinforcement contingencies in groups of males and female rats exhibiting the different phenotypes (i.e., sign-trackers and goal-trackers). In both phenotypes, behavior oriented to the food well was more sensitive to contingency changes (e.g., a reversal in which of two levers was reinforced) than was lever-oriented behavior. That is, the nature of the two behaviors differed independently of the rats in which they were manifest. These results indicate that the behavioral phenotypes reflect the parallel operation of a stimulus-stimulus associative process that gives rise to food-well activity and a stimulus-response process that gives rise to leveroriented activity, rather than the operation of a single process (e.g., stimulus-stimulus) that generates both behaviors
VIP: An Experiment to Search for a Violation of the Pauli Exclusion Principle
The Pauli Exclusion Principle is a basic principle of Quantum Mechanics, and
its validity has never been seriously challenged. However, given its
fundamental standing, it is very important to check it as thoroughly as
possible. Here we describe the VIP (VIolation of the Pauli exclusion principle)
experiment, an improved version of the Ramberg and Snow experiment (E. Ramberg
and G. Snow, {\it Phys. Lett. B} {\bf 238}, 438 (1990)); VIP has just completed
the installation at the Gran Sasso underground laboratory, and aims to test the
Pauli Exclusion Principle for electrons with unprecedented accuracy, down to
. We report preliminary experimental
results and briefly discuss some of the implications of a possible violation.Comment: Plenary talk presented by E. Milotti at Meson 2006, Cracow, 9-13 June
200
New experimental limit on the Pauli Exclusion Principle violation by electrons
The Pauli Exclusion Principle (PEP) is one of the basic principles of modern
physics and, even if there are no compelling reasons to doubt its validity, it
is still debated today because an intuitive, elementary explanation is still
missing, and because of its unique stand among the basic symmetries of physics.
The present paper reports a new limit on the probability that PEP is violated
by electrons, in a search for a shifted K line in copper: the presence
of this line in the soft X-ray copper fluorescence would signal a transition to
a ground state already occupied by 2 electrons. The obtained value, , improves the existing limit by almost two
orders of magnitude.Comment: submitted to Phys. Lett.
New experimental limit on Pauli Exclusion Principle violation by electrons (the VIP experiment)
The Pauli Exclusion Principle is one of the basic principles of modern
physics and is at the very basis of our understanding of matter: thus it is
fundamental importance to test the limits of its validity. Here we present the
VIP (Violation of the Pauli Exclusion Principle) experiment, where we search
for anomalous X-rays emitted by copper atoms in a conductor: any detection of
these anomalous X-rays would mark a Pauli-forbidden transition. ] VIP is
currently taking data at the Gran Sasso underground laboratories, and its
scientific goal is to improve by at least four orders of magnitude the previous
limit on the probability of Pauli violating transitions, bringing it into the
10**-29 - 10**-30 region. First experimental results, together with future
plans, are presented.Comment: To appear in proceedings of the XLVI International Winter Meeting on
Nuclear Physics, Bormio, Italy, January 20-26, 200
The VIP Experiment
The Pauli Exclusion Principle (PEP) is a basic principle of Quantum
Mechanics, and its validity has never been seriously challenged. However, given
its importance, it is very important to check it as thoroughly as possible.
Here we describe the VIP (Violation of PEP) experiment, an improved version of
the Ramberg and Snow experiment (Ramberg and Snow, Phys. Lett. B238 (1990)
438); VIP shall be performed at the Gran Sasso underground laboratories, and
aims to test the Pauli Exclusion Principle for electrons with unprecedented
accuracy, down to Comment: 7 pages, 5 figures, PDF only, presented by Edoardo Milotti to the
conference "Quantum Theory: reconsideration of foundations-3", Vaxjo
(Sweden), June, 6-11 200
Morphometric characteristics of the aortic arch
Departamentul de morfologie, Facultatea de medicină, Universitatea „Ovidius”, Constanţa, România, Conferința Ştiinţifică Internaţională ”Probleme actuale ale morfologiei” dedicată celor 70 de ani de la fondarea Universității de Stat de Medicină și Farmacie „Nicolae Testemiţanu”, Chişinău, 15-16 octombrie 2015Abstract
Our results on the morphometry of the aortic arch were obtained from measurements made on a total of 66 angioCT’s, (18 females and 48 males) and the results were compared by gender. The diameter of the aortic arch above the origin
of the brachiocephalic arterial trunk was found between 25.8 to 37.5 mm. In female it was 26.4 to 29.4 mm range while in
males was between 25.8 to 37.5 mm. The diameter of the aortic arch at the level of the aortic isthmus was found between
20.2 to 28.4 mm, which corresponds to the limits found in males while in females the diameter was 21.3 to 24.1 mm. In
males we have not met more than 28.4 mm in diameter. In 12 cases (38.71% of cases) we assessed a progressive decrease
of the caliber of the ascending aorta from its origin towards the aortic arch (previously to the origin of the brachiocephalic
arterial trunk). Between mid-ascending aorta and the origin of the brachiocephalic trunk the diameter diminished with
0.3 to 1.6 mm, in female from 0.3 to 1.6 mm and in male with 0.3-0.4 mm. Between the brachiocephalic trunk origin and
the aortic isthmus (posterior to the left subclavian artery origin) we measured a decrease of the aortic diameter between
3.2 to 7.2, in female 3.2-3.6 mm and in male from 5.4 to 7.2 mm
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