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Search Results: 1 - 10 of 31041 matches for " Z. Papandreou "
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An Updated Mini Review on Grapefruit: Interactions with Drugs, Obesity and Cardiovascular Risk Factors  [PDF]
Dimitrios Papandreou, Andry Phily
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.54045
Abstract:

The paper examines the effects of grapefruit consumption in relation to drugs, obesity and cardiovascular risk factors. The review includes the most updated studies found in Pub-Med. The grapefruit effect refers to the ability of grapefruit juice and supplements to interact with a wide variety of pharmaceuticals, either enhancing or limiting their systemic availability. Due to altering the active dosage of the pharmaceutical, Grapefruit juice is commonly not allowed to be used alongside with many drugs. Naringin is the most important one, which can inhibit absorption of some drugs but more commonly 67-dihydroxybergamottin, which inhibits CYP3A4. Lately, grapefruit has been found both in rats and adults to reduce body weight, blood pressure, improve lipid and hepatic profile and decrease platelet aggregation. These promising results must be followed by additional studies in order to add to the importance of the role and effects of grapefruit as part of our diet.

Deep Epitomic Convolutional Neural Networks
George Papandreou
Computer Science , 2014,
Abstract: Deep convolutional neural networks have recently proven extremely competitive in challenging image recognition tasks. This paper proposes the epitomic convolution as a new building block for deep neural networks. An epitomic convolution layer replaces a pair of consecutive convolution and max-pooling layers found in standard deep convolutional neural networks. The main version of the proposed model uses mini-epitomes in place of filters and computes responses invariant to small translations by epitomic search instead of max-pooling over image positions. The topographic version of the proposed model uses large epitomes to learn filter maps organized in translational topographies. We show that error back-propagation can successfully learn multiple epitomic layers in a supervised fashion. The effectiveness of the proposed method is assessed in image classification tasks on standard benchmarks. Our experiments on Imagenet indicate improved recognition performance compared to standard convolutional neural networks of similar architecture. Our models pre-trained on Imagenet perform excellently on Caltech-101. We also obtain competitive image classification results on the small-image MNIST and CIFAR-10 datasets.
The Role of Soluble, Insoluble Fibers and Their Bioactive Compounds in Cancer: A Mini Review  [PDF]
Dimitrios Papandreou, Zujaja Tul Noor, Maitha Rashed
Food and Nutrition Sciences (FNS) , 2015, DOI: 10.4236/fns.2015.61001
Abstract: The cancer incidence has risen dramatically over the last decades. About 8 million people died globally according to latest reports, which represented almost 40% more than it was 20 years ago. Risk factors for the development of cancer have been found to include smoking, alcohol, drugs, obesity and diet. Fiber intake has shown to exhibit chemoprotective effects on cancer proliferation and metastasis that may seem to be very promising. This article will review the role of different types of fiber such as, cellulose, lignin, pectin and inulin in development and prevention of different types of cancers. This article would also discuss the effectiveness of both types of fiber in cancer prevention.
Space conditions during a month of a sequence of six M > 6.8 earthquakes ending with the tsunami of 26 December 2004
G. Anagnostopoulos ,A. Papandreou
Natural Hazards and Earth System Sciences (NHESS) & Discussions (NHESSD) , 2012,
Abstract: This paper examines space and seismological data for the time period about one month before the giant Sumatra-Andaman strong (9.3) earthquake (EQ). The combination of seismological and space data reveals some interesting features for this time period: (1) six successive high speed solar wind streams obviously triggering a sudden increase of geomagnetic activity were all followed by strong to giant (M > 6.8) EQs, (2) the 6 strong EQs present certain spatial-temporal constraints, with the epicentre of the EQs occuring at the edges of the Pacific Plate (the Sumatra-Andaman EQ occurred at the end of this series of EQs, eastward of the first one), in a clockwise direction, (3) the EQs occurred after a sudden increase of geomagnetic activity, as inferred from the 3 h-Kp index, following a quiet geomagnetic period and (4) the time delay of the M > 6.2 earthquakes (in the broad area examined) from the last maximum sudden Kp increase was on average ~1.5 days. These findings from the study of the Earth's space environment during the month preceding the Sumatra-Andaman giant (9.3) EQ provide new information for a possible better understanding of the Sun-magnetosphere-lithosphere coupling.
Bit and Power Allocation in Constrained Multicarrier Systems: The Single-User Case
Nikolaos Papandreou,Theodore Antonakopoulos
EURASIP Journal on Advances in Signal Processing , 2007, DOI: 10.1155/2008/643081
Abstract: Multicarrier modulation is a powerful transmission technique that provides improved performance in various communication fields. A fundamental topic of multicarrier communication systems is the bit and power loading, which is addressed in this article as a constrained multivariable nonlinear optimization problem. In particular, we present the main classes of loading problems, namely, rate maximization and margin maximization, and we discuss their optimal solutions for the single-user case. Initially, the classical water-filling solution subject to a total power constraint is presented using the Lagrange multipliers optimization approach. Next, the peak-power constraint is included and the concept of cup-limited waterfilling is introduced. The loading problem is also addressed subject to the integer-bit restriction and the optimal discrete solution is examined using combinatorial optimization methods. Furthermore, we investigate the duality conditions of the rate maximization and margin maximization problems and we highlight various ideas for low-complexity loading algorithms. This article surveys and reviews existing results on resource allocation in constrained multicarrier systems and presents new trends in this area.
Efficient variational inference in large-scale Bayesian compressed sensing
George Papandreou,Alan Yuille
Mathematics , 2011, DOI: 10.1109/ICCVW.2011.6130406
Abstract: We study linear models under heavy-tailed priors from a probabilistic viewpoint. Instead of computing a single sparse most probable (MAP) solution as in standard deterministic approaches, the focus in the Bayesian compressed sensing framework shifts towards capturing the full posterior distribution on the latent variables, which allows quantifying the estimation uncertainty and learning model parameters using maximum likelihood. The exact posterior distribution under the sparse linear model is intractable and we concentrate on variational Bayesian techniques to approximate it. Repeatedly computing Gaussian variances turns out to be a key requisite and constitutes the main computational bottleneck in applying variational techniques in large-scale problems. We leverage on the recently proposed Perturb-and-MAP algorithm for drawing exact samples from Gaussian Markov random fields (GMRF). The main technical contribution of our paper is to show that estimating Gaussian variances using a relatively small number of such efficiently drawn random samples is much more effective than alternative general-purpose variance estimation techniques. By reducing the problem of variance estimation to standard optimization primitives, the resulting variational algorithms are fully scalable and parallelizable, allowing Bayesian computations in extremely large-scale problems with the same memory and time complexity requirements as conventional point estimation techniques. We illustrate these ideas with experiments in image deblurring.
Validation of a Food Frequency Questionnaire for Vitamin D and Calcium Intake in Healthy Female College Students  [PDF]
Dimitrios Papandreou, Nikolaos Rachaniotis, Maryam Lari, Wafa Al Mussabi
Food and Nutrition Sciences (FNS) , 2014, DOI: 10.4236/fns.2014.521216
Abstract: Objective: The objective of this study was to examine the reproducibility and validity of a Food Frequency Questionnaire (FFQ) and assess calcium and vitamin D intake in health female college students. Methods: Thirty-five healthy female students were conveniently selected to participate in the study. None of the subjects were taking any supplements. The FFQ was validated against intakes from a three-day diet food record report (FR). Results: Positive correlations were observed of daily vitamin D (r = 0.82, p < 0.001) and calcium intake (r = 0.74, p < 0.001) derived from FFQ compared with the FR. The mean intake of vitamin D and calcium derived from FFQ and FR were (233 ± 90, 654 ± 391) and (231 ± 79, 611 ± 352), respectively. The FFQ overestimated vitamin D and Calcium by 2 IU /day (95% CI: 8, 9, p < 0.676 and 43 mg/d (95% CI: 20, 65, p < 0.01). Conclusions: The FFQ used in this study shows promising validation evidence to be used in the future for assessing vitamin D and calcium intakes in female students.
Study of Two-Step Mechanisms in Pion Absorption on 6Li, 12C via Deuteron Emission
G. M. Huber,G. J. Lolos,Z. Papandreou,J. Hovdebo,S. I. H. Naqvi,D. F. Ottewell,P. L. Walden,G. Jones,X. Aslanoglou
Physics , 2000, DOI: 10.1016/S0375-9474(02)00678-4
Abstract: The (pi+,pd), and (pi+,dd) reactions were investigated with pions of 100 and 165 MeV kinetic energy on 6Li and 12C targets. In comparison with previously published (pi+,pp) data on the same targets and at the same beam energies, kinematic regions were identified in which the neutron pickup process n+p->d dominated the observed deuteron yield. The importance of this mechanism increases with energy, contributing half of the observed cross section at 165 MeV. The contribution of direct quasi-triton absorption is significant only at 100 MeV.
Helicity Signatures in Subthreshold rho Production on Nuclei
G. J. Lolos,G. M. Huber,A. Shinozaki,Z. Papandreou,E. J. Brash,K. Hossain,M. Iurescu,D. Nordin,G. Garino,K. Maruyama,K. Maeda,T. Suda,A. Toyofuku,A. Sasaki,H. Yamashita
Physics , 2001,
Abstract: We report a helicity analysis of subthreshold rho production on 2H and 12C nuclei at low photoproduction energies and large |t|. The results are indicative of a large longitudinal rho polarization (l=1, m=0) and are consistent with a strong helicity-flip mechanism of rho production. The analysis is model-independent and supports the large mass shift reported from the earlier 3He experiments.
In-Medium rho^0 Spectral Function Study via the 2H, 3He, 12C(gamma,pi+pi-) Reaction
G. M. Huber,G. J. Lolos,Z. Papandreou,A. Shinozaki,E. J. Brash,M. Iurescu,G. Garino,K. Maruyama,K. Maeda,T. Suda,A. Toyofuku,B. K. Jennings,A. Sasaki,H. Yamashita
Physics , 2003, DOI: 10.1103/PhysRevC.68.065202
Abstract: We report a helicity analysis of sub-threshold rho^0 production on 2H, 3He and 12C at low photo-production energies. The results are indicative of a large longitudinal rho^0 polarization (l=1, m=0) and are consistent with a strong helicity-flip production mechanism. This signature is used to extract in-medium rho^0_L invariant mass distributions for all three nuclei in a manner which is less model-dependent than previous measurements. The results are compared to kinematic and phenomenological models of the rho^0 spectral function. The 2H and 3He data distributions support the role of N*(1520) excitation in shaping the in-medium rho^0_L invariant mass distribution, while the 12C distributions are consistent with quasi-free rho^0_L production. The data support an in-medium modification of the rho^0_L invariant mass distribution.
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