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Search Results: 1 - 10 of 17 matches for " Dangwé Temoua Naibé "
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Long-Term Re-Admission after Hospital Discharge in Patients Admitted with Acute Heart Failure: The Prognostic Value of the Six-Minute Walk Test Distance  [PDF]
Dakaboué Germain Mandi, Dangwé Temoua Naibé, Joel Bamouni, Rélwendé Aristide Yaméogo, Yibar Kambiré, Koudougou Jonas Kologo, Georges Rosario Christian Millogo, Nobila Valentin Yaméogo, Anna Thiam Tall, Patrice Zabsonré
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104841
Abstract:
Background: We sought the value of the six-minute walk test distance in predicting re-admission in patients with chronic heart failure (CHF) in the department of cardiology, Yalgado Ouédraogo University Hospital, Ouaga-dougou, Burkina Faso. Methods: We did a prospective observational study in patients hospitalized with acute decompensated heart failure and who underwent a 6-minute walk test (6-MWT) at their discharge from hospital. The primary end-point was hospital re-admission for heart failure de-compensation. Results: Sixty-one patients (52% females, mean age 46.9 ± 14.1 years, mean left ventricular ejection fraction 32.4 ± 8.2%, mean 6-MWT distance 336.3 ± 65 meters) were followed-up for a 277.6 ± 129.8 days’ period. Twenty-one patients (45.3 percent person-years) were re-admitted. Re-admitted patients had shorter 6-MWT distance (p = 0.007) and were more likely to die than those who were not re-admitted (RR = 1.72, 95% CI = 1.13 - 2.62, p = 0.003). Multivariate Cox regression analysis showed that re-admission was independently predicted by shorter 6-MWT distance (p < 0.001), New York Heart Association class III (p = 0.03), older age p = 0.03) and lower LVEF (p = 0.02). Conclusion: Distance covered during the six-minute walk test is an independent predictor of hospital re-admission for heart failure decompensation in patients with chronic heart failure.
Control of systems with asymmetric bounds using linear programming: Application to a hydrogen reformer
M. Naib,F. Tadeo,A. Benzaouia
Mathematical Problems in Engineering , 2006, DOI: 10.1155/mpe/2006/19092
Abstract: This paper studies controller design for feedback systems in the presence of asymmetrically bounded signals, using a case study. An asymmetric objective functional is used to consider the asymmetrically bounded signals, which makes possible to derive a linear programming problem. Solving this LP makes possible to design controllers that minimize certain outputs, fulfilling at the same time hard constraints on certain signals. The method is presented by application to a hydrogen reformer, a system in petrochemical plants that produces hydrogen from hydrocarbons: a mixed sensitivity problem is stated and solved, with an additional constraint given by the asymmetric limitations on the magnitude and rate of the control signal, and the asymmetricity in the disturbances.
Stabilization of fuzzy systems with constrained controls by using positively invariant sets
A. El Hajjaji,A. Benzaouia,M. Naib
Mathematical Problems in Engineering , 2006, DOI: 10.1155/mpe/2006/13832
Abstract: We deal with the extension of the positive invariance approach to nonlinear systems modeled by Takagi-Sugeno fuzzy systems. The saturations on the control are taken into account during the design phase. Sufficient conditions of asymptotic stability are given ensuring at the same time that the control is always admissible inside the corresponding polyhedral set. Both a common Lyapunov function and piecewise Lyapunov function are used.
Control of systems with asymmetric bounds using linear programming: application to a hydrogen reformer
M. Naib,F. Tadeo,A. Benzaouia
Mathematical Problems in Engineering , 2006,
Abstract: This paper studies controller design for feedback systems in the presence of asymmetrically bounded signals, using a case study. An asymmetric objective functional is used to consider the asymmetrically bounded signals, which makes possible to derive a linear programming problem. Solving this LP makes possible to design controllers that minimize certain outputs, fulfilling at the same time hard constraints on certain signals. The method is presented by application to a hydrogen reformer, a system in petrochemical plants that produces hydrogen from hydrocarbons: a mixed sensitivity problem is stated and solved, with an additional constraint given by the asymmetric limitations on the magnitude and rate of the control signal, and the asymmetricity in the disturbances.
The Immediate Environments of Two Herbig Be Stars: MWC 1080 and HD 259431
Dan Li,Naibí Mari?as,Charles M. Telesco
Physics , 2014, DOI: 10.1088/0004-637X/796/2/74
Abstract: Deep mid-infrared (10-20 $\mu$m) images with sub-arcsec resolution were obtained for two Herbig Be stars, MWC 1080 and HD 259431, to probe their immediate environments. Our goal is to understand the origin of the diffuse nebulosities observed around these two very young objects. By analyzing our new mid-IR images and comparing them to published data at other wavelengths, we demonstrate that the well extended emission around MWC 1080 traces neither a disk nor an envelope, but rather the surfaces of a cavity created by the outflow from MWC 1080A, the primary star of the MWC 1080 system. In the N-band images, the filamentary nebulosities trace the hourglass-shaped gas cavity wall out to $\sim$0.15 pc. This scenario reconciles the properties of the MWC 1080 system revealed by a wide range of observations. Our finding confirms that the environment around MWC 1080, where a small cluster is forming, is strongly affected by the outflow from the central Herbig Be star. Similarities observed between the two subjects of this study suggest that the filamentary emission around HD 259431 may arise from a similar outflow cavity structure, too.
On improving the convergence rate of linear continuous-time systems subject to asymmetrically constrained control
A. Baddou,M. Naib,F. Tadeo,A. Benzaouia
Mathematical Problems in Engineering , 2006, DOI: 10.1155/mpe/2006/89429
Abstract: This paper solves the problem of controlling linear continuous-time systems subject to control signals constrained in magnitude (maybe asymmetrically). A controller design methodology is proposed, based on using an asymmetric Lyapunov function, that avoids the discontinuities in the control vector components resulting from the application of a piecewise linear control law previously proposed. The proposed method gives improved speed of convergence without discontinuities of the control vector components, respecting always the imposed asymmetric constraints. An example illustrates the approach.
Coplanar Waveguides Incorporating Srrs or Csrrs: a Comprehensive Study
Ibraheem A. I. Al-Naib;Martin Koch
PIER B , 2010, DOI: 10.2528/PIERB10061602
Abstract: We numerically and experimentally evaluate different designs of coplanar waveguides (CPWs) loaded with split ring resonators (SRRs) and complementary split ring resonators (CSRRs), respectively. In particular, we are interested in their stop-band performance. Starting from structures which consist of two concentric rings, we study devices with only an outer ring, an inner ring or multiple concentric rings. Furthermore, our study shows that introducing slots in the proximity of the SRR or CSRR will modify the stop-band considerably. Single and multiple unit cells for both designs are fabricated and measured. Our results demonstrate the potential of the CSRR/CPW structure for filter applications.
Single Metal Layer CPW Metamaterial Bandpass Filter
Ibraheem A. I. Al-Naib;Christian Jansen;Martin Koch
PIER Letters , 2010, DOI: 10.2528/PIERL10081103
Abstract: We propose single metal layer metamaterial bandpass filters based on compact complementary u-shaped resonators. Previously, metamaterial bandpass filters could only be achieved if a second conducting layer was utilized. Here, we propose a resonator concept that can directly be integrated with a single sided coplanar waveguide, enabling low fabrication costs and simple system integration. Furthermore, already a single unit cell yields a pronounced bandpass behavior without the need for cascading multiple resonators. Both, measurements and numerical simulations are presented. Using RO3003 as substrate, a low insertion loss of 1.71 dB and a corresponding 3-dB bandwidth ratio of 3.1% is achieved.
High harmonic generation in undoped graphene: Interplay of inter- and intraband dynamics
Ibraheem Al-Naib,J. E. Sipe,Marc M. Dignam
Physics , 2014, DOI: 10.1103/PhysRevB.90.245423
Abstract: We develop a density matrix formalism in the length gauge to calculate the nonlinear response of intrinsic monolayer graphene at terahertz frequencies. Employing a tight-binding model, we find that the interplay of the interband and intraband dynamics leads to strong harmonic generation at moderate field amplitudes. In particular, we find that at low temperature, the reflected field of undoped suspended graphene exhibits a third harmonic amplitude that is 32% of the fundamental for an incident field of 100 V/cm. Moreover, we find that up to the seventh harmonic and beyond are generated.
Membrane metamaterial resonators with a sharp resonance: A comprehensive study towards practical terahertz filters and sensors
Yongyao Chen,Ibraheem A. I. Al-Naib,Jianqiang Gu,Mingwei Wang
AIP Advances , 2012, DOI: 10.1063/1.4704549
Abstract: We investigate the resonant properties of high quality-factor membrane-based metamaterial resonators functioning in the terahertz regime. A number of factors, including the resonator geometry, dielectric loss, and most importantly the membrane thickness are found to extensively influence the resonance strength and quality factor of the sharp resonance. Further studies on the membrane thickness-dependent-sensitivity for sensing applications reveal that high quality-factor membrane metamaterials with a moderate thickness ranging from 10 to 50 μm are the most promising option towards developing realistic integrated terahertz filters and sensors.
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