655 research outputs found
Modelling cortico basal-ganglionic loops and the development of sequential information encoding
A connectionist model consisting of thirty cortico-basal ganglionic loops was implemented. This model encodes temporal information into a spatial pattern of neuronal activations in the prefrontal cortex using neurophysiologically plausible activation functions and circuitry without learning. This neural architecture was used to model experiments with infants. Initial results suggest that the cortical basal ganglionic circuitry has an inherent ability to differentiate sequential information
Noise Thresholds for Higher Dimensional Systems using the Discrete Wigner Function
For a quantum computer acting on d-dimensional systems, we analyze the
computational power of circuits wherein stabilizer operations are perfect and
we allow access to imperfect non-stabilizer states or operations. If the noise
rate affecting the non-stabilizer resource is sufficiently high, then these
states and operations can become simulable in the sense of the Gottesman-Knill
theorem, reducing the overall power of the circuit to no better than classical.
In this paper we find the depolarizing noise rate at which this happens, and
consequently the most robust non-stabilizer states and non-Clifford gates. In
doing so, we make use of the discrete Wigner function and derive facets of the
so-called qudit Clifford polytope i.e. the inequalities defining the convex
hull of all qudit Clifford gates. Our results for robust states are provably
optimal. For robust gates we find a critical noise rate that, as dimension
increases, rapidly approaches the the theoretical optimum of 100%. Some
connections with the question of qudit magic state distillation are discussed.Comment: 14 pages, 1 table; Minor changes vs. version
Alteration of Endothelins: A Common Pathogenetic Mechanism in Chronic Diabetic Complications
Endothelin (ET) peptides perform several physiological, vascular,
and nonvascular functions and are widely distributed in a number
of tissues. They are altered in several disease processes including
diabetes. Alteration of ETs have been demonstrated in organs
of chronic diabetic complications in both experimental and clinical
studies. The majority of the effects of ET alteration in diabetes
are due to altered vascular function. Furthermore, ET antagonists
have been shown to prevent structural and functional changes induced
by diabetes in animal models. This review discusses the contribution
of ETs in the pathogenesis and the potential role of ET
antagonism in the treatment of chronic diabetic complications
A Model for Neutrino Masses and Dark Matter
We propose a model for neutrino masses that simultaneously results in a new
dark matter candidate, the right-handed neutrino. We derive the dark matter
abundance in this model, show how the hierarchy of neutrino masses is obtained,
and verify that the model is compatible with existing experimental results. The
model provides an economical method of unifying two seemingly separate puzzles
in contemporary particle physics and cosmology.Comment: 4 pages, submitted to PR
Release of infectious hepatitis C virus from huh7 cells occurs via a trans-golgi network-to-endosome pathway independent of very-low-density lipoprotein secretion
© 2016 Mankouri et al. The release of infectious hepatitis C virus (HCV) particles from infected cells remains poorly characterized. We previously demonstrated that virus release is dependent on the endosomal sorting complex required for transport (ESCRT). Here, we show a critical role of trans-Golgi network (TGN)-endosome trafficking during the assembly, but principally the secretion, of infectious virus. This was demonstrated by both small interfering RNA (siRNA)-mediated silencing of TGN-associated adaptor proteins and a panel of dominant negative (DN) Rab GTPases involved in TGN-endosome trafficking steps. Importantly, interfering with factors critical for HCV release did not have a concomitant effect on secretion of triglycerides, ApoB, or ApoE, indicating that particles are likely released from Huh7 cells via pathways distinct from that of very-low-density lipoprotein (VLDL). Finally, we show that HCV NS2 perturbs TGN architecture, redistributing TGN membranes to closely associate with HCV core protein residing on lipid droplets. These findings support the notion that HCV hijacks TGN-endosome trafficking to facilitate particle assembly and release. Moreover, although essential for assembly and infectivity, the trafficking of mature virions is seemingly independent of host lipoproteins
The Global Emerging Infection Surveillance and Response System (GEIS), a U.S. government tool for improved global biosurveillance: a review of 2009
The Armed Forces Health Surveillance Center, Global Emerging Infections Surveillance and Response System (AFHSC-GEIS) has the mission of performing surveillance for emerging infectious diseases that could affect the United States (U.S.) military. This mission is accomplished by orchestrating a global portfolio of surveillance projects, capacity-building efforts, outbreak investigations and training exercises. In 2009, this portfolio involved 39 funded partners, impacting 92 countries. This article discusses the current biosurveillance landscape, programmatic details of organization and implementation, and key contributions to force health protection and global public health in 2009
A survey of abnormalities in the colon and rectum in patients with haemorrhoids
Abstract Background Haemorrhoids are a common problem in daily practice. However, symptoms may also be caused by other abnormalities in the rectum or colon. Data on the presence of these abnormalities in patients with haemorrhoids is sparse. To examine the prevalence of abnormalities of the colon or rectum in patients with and without haemorrhoids, stratified for age. Methods In a 17-year period 1910 consecutive patients with haemorrhoids and 7936 patients without haemorrhoids were analysed retrospectively. All of these patients had an endoscopic examination for different clinical reasons. All significant endoscopic co-findings (diverticuli, polyps, cancer, angiodysplasia and varices, or colitis) were recorded. Results The patients were divided in 2 groups. Group 1 (n = 861 (45.1%)) consisted of patients with only haemorrhoids, group 2 (n = 1049 (54.9%)) consisted of patients with haemorrhoids and another endoscopic diagnosis. Patients in group 1 were significantly younger, mean age 55.3 ± 14.1 years versus 67.4 ± 12.1 years (p Conclusion In patients with haemorrhoids other abnormalities can be present. Especially in older patients the clinician must be cautious to attribute complaints solely to haemorrhoids.</p
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