Optimization of the extraordinary magnetoresistance in semiconductor-metal hybrid structures for magnetic-field sensor applications

Semiconductor-metal hybrid structures can exhibit a very large geometrical magnetoresistance effect, the so-called extraordinary magnetoresistance (EMR) effect. In this paper, we analyze this effect by means of a model based on the finite element method and compare our results with experimental data. In particular, we investigate the important effect of the contact resistance $\rho_c$ between the semiconductor and the metal on the EMR effect. Introducing a realistic $\rho_c=3.5\times 10^{-7} \Omega{\rm cm}^2$ in our model we find that at room temperature this reduces the EMR by 30% if compared to an analysis where $\rho_c$ is not considered.Comment: 4 pages; manuscript for MSS11 conference 2003, Nara, Japa

Teleportation of a Zero-and One-photon Running Wave State by Projection Synthesis

We show how to teleport a running wave superposition of zero- and one-photon field state through the projection synthesis technique. The fidelity of the scheme is computed taking into account the noise introduced by dissipation and the efficiency of the detectors. These error sources have been introduced through a single general relationship between input and output operators.Comment: 11 pages, 1 figur

Confined spin waves reveal an assembly of nanosize domains in ferromagnetic La(1-x)CaxMnO3 (x=0.17,0.2)

We report a study of spin-waves in ferromagnetic La$_{1-x}$Ca$_{x}$MnO$_3$, at concentrations x=0.17 and x=0.2 very close to the metallic transition (x=0.225). Below T$_C$, in the quasi-metallic state (T=150K), nearly q-independent energy levels are observed. They are characteristic of standing spin waves confined into finite-size ferromagnetic domains, defined in {\bf a, b) plane for x=0.17 and in all q-directions for x=0.2. They allow an estimation of the domain size, a few lattice spacings, and of the magnetic coupling constants inside the domains. These constants, anisotropic, are typical of an orbital-ordered state, allowing to characterize the domains as "hole-poor". The precursor state of the CMR metallic phase appears, therefore, as an assembly of small orbital-ordered domains.Comment: 4 pages, 5 figure

An exact master equation for the system-reservoir dynamics under the strong coupling regime and non-Markovian dynamics

In this paper we present a method to derive an exact master equation for a bosonic system coupled to a set of other bosonic systems, which plays the role of the reservoir, under the strong coupling regime, i.e., without resorting to either the rotating-wave or secular approximations. Working with phase-space distribution functions, we verify that the dynamics are separated in the evolution of its center, which follows classical mechanics, and its shape, which becomes distorted. This is the generalization of a result by Glauber, who stated that coherent states remain coherent under certain circumstances, specifically when the rotating-wave approximation and a zero-temperature reservoir are used. We show that the counter-rotating terms generate fluctuations that distort the vacuum state, much the same as thermal fluctuations.Finally, we discuss conditions for non-Markovian dynamics

Evaluation De La Prise En Charge De La Malnutrition Aigüe Sévère Dans Le Service De CRENI Du Centre Hospitalier Régional (CHR) De Niamey

Introduction L’objectif de notre étude est d’évaluer la prise en charge de la malnutrition aigüe sévère dans le centre de récupération nutritionnelle intensive du centre hospitalier régional de Niamey. Matériels et méthodes : nous avons mené une étude prospective de soins courants réalisée entre le 1er janvier 2016 et le 31 décembre 2016 en incluant les enfants de 0 à 59 mois qui présentaient un rapport poids/taille ≤ - 3 Z score et ou des œdèmes de dénutrition chez lesquels une malformation cardiaque ou néoplasies ou autres maladies chroniques étaient éliminées. Le protocole national de la récupération nutritionnelle est divisé en phase 1 pendant laquelle les patients sont mis sous le lait F-75 (130ml/kg/j), en phase de transition avec la mise sous le F-100 (130ml/kg/j) et en phase 2 pendant laquelle les patients sont mis sous l’alimentation thérapeutique près à l’emploi et ou le F-100. Le passage d’une phase à une autre est bien codifié par le protocole. Résultats : Durant la période de l’étude, 5773 patients ont été recensés, parmi lesquels 814 étaient atteints de MAS soit une fréqureprésentaient 75%. Le marasme représentait 86,30% des cas de malnutrition, le kwashiorkor 5,03% et la forme mixte 8,70%. La grande majorité des malades (91,52%) avait un Z score ≤ - 3. L’ECBU était positive chez 85 patients. L’E Coli représentait 87% des germes rencontrés. Les facteurs de comorbidité étaient le paludisme (88,8%) ; les pneumopathies (5,28%) et le VIH (1,4%). Les principales complications rencontrées au cours de l’hospitalisation étaient la déshydratation (26,5%), la détresse respiratoire (6,14%) et l’hypothermie (3,2%). La durée moyenne de séjour hospitalier était de 15,7±5,2 jours et 12% des patients avaient un séjour de plus de 20 jours. Le gain pondéral moyen journalier était de 12,5±3,9g/kg/jour. Nous avions enregistré 66 cas de décès (8,1%). Conclusion: L’étude montre une prévalence très élevée du marasme, une prédominance des enfants de moins de 24 mois et une mortalité élevée chez les nourrissons. Promouvoir une bonne diversification alimentaire chez le nourrisson permettrait d’améliorer la situation. ence de 14,1% de toutes les pathologies rencontrées dans notre service. Le sexe masculin était prédominant (52,5%) avec l’âge moyen des patients à 14,4±9,14 mois. Les patients issus de familles à niveau de vie faible  représentaient 75%. Le marasme représentait 86,30% des cas de malnutrition, le kwashiorkor 5,03% et la forme mixte 8,70%. La grande majorité des malades (91,52%) avait un Z score ≤ - 3. L’ECBU était positive chez 85 patients. L’E Coli représentait 87% des germes rencontrés. Les facteurs de comorbidité étaient le paludisme (88,8%) ; les pneumopathies (5,28%) et le VIH (1,4%). Les principales complications rencontrées au cours de l’hospitalisation étaient la déshydratation (26,5%), la détresse respiratoire (6,14%) et l’hypothermie (3,2%). La durée moyenne de séjour hospitalier était de 15,7±5,2 jours et 12% des patients avaient un séjour de plus de 20 jours. Le gain pondéral moyen journalier était de 12,5±3,9g/kg/jour. Nous avions enregistré 66 cas de décès (8,1%). Conclusion: L’étude montre une prévalence très élevée du marasme, une prédominance des enfants de moins de 24 mois et une mortalité élevée chez les nourrissons. Promouvoir une bonne diversification alimentaire chez le nourrisson permettrait d’améliorer la situation.   Background: The objective of our study is to evaluate the management of severe acute malnutrition in the intensive nutrition recovery center of the Regional Hospital Center of Niamey.Methods: we carried out a prospective study of routine care performed between January 1, 2016 and December 31, 2016 including children from 0 to 59 months who presented a weight / height ratio ≤ - 3 Z score and or edema of undernutrition in which a heart malformation or neoplasms or other chronic diseases were eliminated. The national protocol for nutritional recovery is divided into phase 1 during which patients are put on F-75 milk (130ml / kg / d), in the transition phase with putting on F-100 (130ml / kg / d ) and in phase 2 during which the patients are put on therapeutic food ready for use and / or F-100. The transition from one phase to another is well codified by the protocol. Results: During the study period, 5,773 patients were identified, among which 814 had SAM, ie a frequency of 14.1% of all pathologies encountered in our department. Male sex was predominant (52.5%) with the mean age of patients at 14.4 ± 9.14 months. Patients from families with a low standard of living accounted for 75%. Marasmus accounted for 86.30% of malnutrition cases, kwashiorkor 5.03% and mixed form 8.70%. The vast majority of patients (91.52%) had a Z score ≤ - 3. The urine culture was positive in 85 patients. E Coli accounted for 87% of the germs encountered. The comorbid factors were malaria (88.8%); pneumonia (5.28%) and HIV (1.4%). The main complications encountered during hospitalization were dehydration (26.5%), respiratory distress (6.14%) and hypothermia (3.2%). The mean length of hospital stay was 15.7 ± 5.2 days and 12% of patients had a stay of more than 20 days. The mean daily weight gain was 12.5 ± 3.9g / kg / day. We had recorded 66 cases of death (8.1%)

In vitro toxicity of nanoceria: effect of coating and stability in biofluids

Due to the increasing use of nanometric cerium oxide in applications, concerns about the toxicity of these particles have been raised and have resulted in a large number of investigations. We report here on the interactions between 7 nm anionically charged cerium oxide particles and living mammalian cells. By a modification of the particle coating including low-molecular weight ligands and polymers, two generic behaviors are compared: particles coated with citrate ions that precipitate in biofluids and particles coated with poly(acrylic acid) that are stable and remain nanometric. We find that nanoceria covered with both coating agents are taken up by mouse fibroblasts and localized into membrane-bound compartments. However, flow cytometry and electron microscopy reveal that as a result of their precipitation, citrate-coated particles interact more strongly with cells. At cerium concentration above 1 mM, only citrate-coated nanoceria (and not particles coated with poly(acrylic acid)) display toxicity and moderate genotoxicity. The results demonstrate that the control of the surface chemistry of the particles and its ability to prevent aggregation can affect the toxicity of nanomaterials.Comment: 33 pages 10 figures, accepted at Nanotoxicolog

Thirty Femtograms Detection of Iron in Mammalian Cells

Inorganic nanomaterials and particles with enhanced optical, mechanical or magnetic attributes are currently being developed for a wide range of applications. Safety issues have been formulated however concerning their potential cyto- and genotoxicity. For in vivo and in vitro experimentations, recent developments have heightened the need of simple and facile methods to measure the amount of nanoparticles taken up by cells or tissues. In this work, we present a rapid and highly sensitive method for quantifying the uptake of iron oxide nanoparticles in mammalian cells. Our approach exploits the digestion of incubated cells with concentrated hydrochloric acid reactant and a colorimetric based UV-Visible absorption technique. The technique allows the detection of iron in cells over 4 decades in masses, from 0.03 to 300 picograms per cell. Applied on particles of different surface chemistry and sizes, the protocol demonstrates that the coating is the key parameter in the nanoparticle/cell interactions. The data are corroborated by scanning and transmission electron microscopy and stress the importance of resiliently adsorbed nanoparticles at the plasma membrane.Comment: 18 pages, 6 figure

Three path interference using nuclear magnetic resonance: a test of the consistency of Born's rule

The Born rule is at the foundation of quantum mechanics and transforms our classical way of understanding probabilities by predicting that interference occurs between pairs of independent paths of a single object. One consequence of the Born rule is that three way (or three paths) quantum interference does not exist. In order to test the consistency of the Born rule, we examine detection probabilities in three path intereference using an ensemble of spin-1/2 quantum registers in liquid state nuclear magnetic resonance (LSNMR). As a measure of the consistency, we evaluate the ratio of three way interference to two way interference. Our experiment bounded the ratio to the order of $10^{-3} \pm 10^{-3}$, and hence it is consistent with Born's rule.Comment: 11 pages, 4 figures; Improved presentation of figures 1 and 4, changes made in section 2 to better describe the experiment, minor changes throughout, and added several reference

Continuous pumping and control of mesoscopic superposition state in a lossy QED cavity

Here we consider the continuous pumping of a dissipative QED cavity and derive the time-dependent density operator of the cavity field prepared initially as a superposition of mesoscopic coherent states. The control of the coherence of this superposition is analyzed considering the injection of a beam of two-level Rydberg atoms through the cavity. Our treatment is compared to other approaches.Comment: 15 pages, 6 PostScript figures, To appear in Phys. Rev.