56 research outputs found

    An Exploration of the Ideology of Health Promotion and Critical Implications for Public health

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    This dissertation analyzes the ideological, conceptual, and moral foundations of health promotion discourse. It highlights their implications for the field of public health and for broader socio-cultural contexts. Using a critical interpretive qualitative approach, the study employs semi-structured interviews to understand how conceptions of health promotion are articulated by a group of professional health coaches. Additionally, written and visual health communication and social marketing materials from the Centers for Disease Control and Prevention are examined through qualitative discourse analysis. Findings from both sets of data are convergent and support the claim that, currently, the pursuit of health is mainly justified with reference to an individualistic, rationalistic and moralizing doctrine that continues to be pervasive. This translates into professional recommendations which stress individual responsibility for achieving health through discrete behavioral and lifestyle changes. iv It is argued that the dominant approach in health promotion discourse fails to integrate a coherent understanding of the structural determinants of health and does not take into account the complexity of the production of health, nor the rich phenomenology of health in daily life. The present dominant status of individualistic conceptions of health contributes to the spread of a reductive understanding of health among the citizenry. The study points to critical public health implications, including the urgent need for integrating social determinants in the pervasive professional ideology of health. As the health promotion workforce - such as health coaches - is expected to grow at a fast pace in the near future, it is imperative that a more comprehensive conception of health production be incorporated into the training of health promotion and of health professionals, generally. Additionally, efforts should be made so that the social determinants of health become integrated into public debate, public policy agendas, and health communication. This analysis favored depth over scope. The main limitation of the study is the small number of interviews with health coaches from a single organization. Additional empirical studies are needed to include other health promotion and health care groups as well as lay participants, and to integrate a comparative perspective into the analysis

    Alternative Solutions for Data Storage Using Magnetic Films Exchange-Coupled Through Non-Magnetic Layer

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    We describe an alternative solution to encode information in magnetic films that goes beyond the conventional way of digital magnetic recording. In our approach the information is stored via a continuous variable, namely the remanent coupling angle between two magnetic films that are separated by a nonmagnetic spacer layer. Using the technique of nuclear resonant scattering (NRS) [1, 2] we show with good precision, how this coupling angle can be conveniently adjusted with high degree of remanence by shortly applied external magnetic fields. Moreover this effect is explained using a micromagnetic model [3, 4]. Extremely important for future applications of this concept, we demonstrate, that the remanent coupling angles can be read out via magneto-optical or magneto-resistance effects. In principle, this approach allows to design novel memory cells for advance data storage devices, where multiple states per unit cell can be generated and recorded

    Partial least squares model of moulting accelerating compounds with insecticide activity against lepidopteran species

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    In this study the insecticidal activity of a series of 33 dibenzoylhydrazinederivatives, expressed as the pEC50activity measured in vitro, based on an ecdysone-dependent reporter assay using cell lines derived from one lepidopteran species (the cotton leafworm Spodoptera littoralis), was correlated with structural descriptors using the partial least squares (PLS) approach. The data set was energy pre-optimized by molecular mechanics calculations using the MMFF94s force field. Several 0D, 1D, 2D and 3D descriptors were calculated for the minimum energy conformers. A two-components PLS model was obtained with acceptable statistical quality (R2X(Cum) = 0.705, R2Y(cum) = 0.821 and Q2 (Cum) = 0.793) for modeling the insecticidal activity. The model goodness of fit tested with the Y-randomization test indicated a stable model. Specific dibenzoylhydrazine structural features supplying information about topological distances and descriptors sensitive to any conformational change influence the insecticidal activity

    Canagliflozin and renal outcomes in type 2 diabetes and nephropathy

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    BACKGROUND Type 2 diabetes mellitus is the leading cause of kidney failure worldwide, but few effective long-term treatments are available. In cardiovascular trials of inhibitors of sodium–glucose cotransporter 2 (SGLT2), exploratory results have suggested that such drugs may improve renal outcomes in patients with type 2 diabetes. METHODS In this double-blind, randomized trial, we assigned patients with type 2 diabetes and albuminuric chronic kidney disease to receive canagliflozin, an oral SGLT2 inhibitor, at a dose of 100 mg daily or placebo. All the patients had an estimated glomerular filtration rate (GFR) of 30 to <90 ml per minute per 1.73 m2 of body-surface area and albuminuria (ratio of albumin [mg] to creatinine [g], >300 to 5000) and were treated with renin–angiotensin system blockade. The primary outcome was a composite of end-stage kidney disease (dialysis, transplantation, or a sustained estimated GFR of <15 ml per minute per 1.73 m2), a doubling of the serum creatinine level, or death from renal or cardiovascular causes. Prespecified secondary outcomes were tested hierarchically. RESULTS The trial was stopped early after a planned interim analysis on the recommendation of the data and safety monitoring committee. At that time, 4401 patients had undergone randomization, with a median follow-up of 2.62 years. The relative risk of the primary outcome was 30% lower in the canagliflozin group than in the placebo group, with event rates of 43.2 and 61.2 per 1000 patient-years, respectively (hazard ratio, 0.70; 95% confidence interval [CI], 0.59 to 0.82; P=0.00001). The relative risk of the renal-specific composite of end-stage kidney disease, a doubling of the creatinine level, or death from renal causes was lower by 34% (hazard ratio, 0.66; 95% CI, 0.53 to 0.81; P<0.001), and the relative risk of end-stage kidney disease was lower by 32% (hazard ratio, 0.68; 95% CI, 0.54 to 0.86; P=0.002). The canagliflozin group also had a lower risk of cardiovascular death, myocardial infarction, or stroke (hazard ratio, 0.80; 95% CI, 0.67 to 0.95; P=0.01) and hospitalization for heart failure (hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001). There were no significant differences in rates of amputation or fracture. CONCLUSIONS In patients with type 2 diabetes and kidney disease, the risk of kidney failure and cardiovascular events was lower in the canagliflozin group than in the placebo group at a median follow-up of 2.62 years

    Remarkable Magnetic Properties in a Mn<sub>73.6</sub>Ga<sub>26.4</sub> Alloy Produced via Out-of-Equilibrium Method

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    Rare-earth-free permanent magnets with the L10 phase are actively researched for their potential as a future class of magnetic materials, capable of operating at higher temperatures and in challenging corrosion environments such as renewable energy applications. Among these classes, MnGa shows potential, being cost effective and having interesting magnetic properties. A MnGa magnetic alloy, with composition Mn73.6Ga26.4 in atomic percent, was produced via the out-of-equilibrium method, and its structural and magnetic properties were assessed using X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and extended magnetic characterization. We show that the MnGa alloy submitted to thermal annealing in optimal conditions exhibits a two-phase microstructure, where small nanocrystals of tetragonal L10/D022 magnetic phase are embedded within a D019 MnGa matrix of a non-collinear antiferromagnetic nature. These co-existing, magnetically different phases produce an optimal set of promising magnetic properties, larger than the values reported in the literature for single-phase MnGa alloys and thin films. Such large values are explained by the exchange coupling between competing non-collinear magnetic sublattices of the D019 MnGa with the net moment of the small magnetic nanocrystals of tetragonal symmetry

    Magnétoélectronique non-colinéaire dans les nanotubes de carbone mono-feuillets

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    Recent developments in the field of nanotechnology allowed the access to adequate length scale necesary to closely investigate spins and opened large prospects of using electrons spin degree of freedom in new generation electronic devices. This have lead to the development of a vibrant field dubbed spintronics.Here, we present experiments that combine two very promising materials: namely cardon nanotubes and palladium-nickel (PdNi), with the purpose to manipulate the electronic spin both in the classical and in the quantum regime. We implement a quantum dot connected to two non-collinear ferromagnetic leads that acts as a spin-valve device. The versatility of carbon nanotubes to fabricate quantum dots when connected to PdNi electrodes via tunneling barriers is combined with the particular transversal anisotropy of the PdNi when shaped in nanometric stripes.For devices exploiting actively the electronic spin, however control over classical or quantum spin rotations has still to be achieved. A detailed understanding of the magnetic characteristics of PdxNi 100-x alloy is crucial both for understanding the switching characteristics of such the spin-valve device and for optimizing its electronic properties. We present a magnetic study of Pd20Ni80 and Pd90Ni10 nanostripes by means of extraordinary Hall effect measurements, at low temperature, for various dimensions, thicknesses and capping films. In the case of Pd20Ni80, this experiment is a first at low temperature.The CNT-based device proposed here was tested both in linear and nonlinear transportregimes. While the linear spin dependent transport displays the usual signatures of electronicconfinement, the finite bias magnetoresistance displays an impressive magnetoresistance antisymmetric reversal in contrast with the linear regime. This effect can only be understood if electronic interactions are considered. It is accompanied by a linear dispersion of the zeromagnetoresistance point in the bias-field plane. Simulations based on a proposed model confirm a current induced spin precession, electrically tunable due to the quantum nature ofthe device.Les développements récents des nanotechnologies ont permis d’accéder à des dimensions qui permettent d’’étudier les spins des électrons. Ceci ouvre la voie à l’utilisation du degré de liberté du spin des électrons dans des dispositifs électroniques de nouvelle génération. C’est l’origine d’un nouveau domaine de recherche prometteur baptisé spintronique.Dans ce travail, on présente des expériences dans le domaine de la spintronique en utilisant deux matériaux très prometteurs : les nanotubes de carbone (CNT) et le palladiumnickel (PdNi), un ferromagnet versatile dans le but de manipuler le spin électronique dans les deux régimes, classiques et quantiques. Une compréhension détaillée des caractéristiques magnétiques de PdxNi 100-x devient cruciale à la fois pour comprendre les caractéristiques de basculement d’un tel dispositif mais aussi pour optimiser ses propriétés électroniques.Une étude sur des structures micrométrique et nanométrique en PdNi a été menée grâce à des mesures de l’effet Hall extraordinaires (EHE sur des croix lithographiées). Les analyses montrent que la géométrie, l’épaisseur, la composition chimique ainsi que la couche de recouvrement, ont tous une influence sur l’aimantation des électrodes de PdNi, en particulier celles de taille nanométrique. Cela est dû à la relaxation des contraintes sur les bords qui devient important pour les dispositifs de petites dimensions.On met en place un point quantique connecté `a deux contacts ferromagnétiques non colinéaires (source et drain), évaporées sur le CNT; le nanotube est connecté à une tension de grille pendant qu’une source de tension source-drain est utilisée pour varier le potentiel chimiques des ferromagnets. Les électrodes sont conçues pour former un angle téta = Pi/2. On attend alors un comportement similaire à celui d’une vanne de spin, donc un effet fini de magnétorésistance à effet tunnel est à prévoir.Des mesures de transport de spin ont révélé un régime de blocage de Coulomb, confirmé par la spectroscopie de transport. Les régimes linéaires et non-linéaires ont été également testés.En régime linéaire, les résultats montrent un signal de TMR lorsqu’il est placé dans un champ qui est balayé, un comportement typique pour un dispositif vanne de spin. Dans le régime non linéaire, ont été obtenues des variations du signal d’hystérésis lorsque la polarisation change de signe. De plus, la TMR affiche un comportement presque antisymétrique avec la conductance. Les mesures réalisées pour différentes valeurs de la tension grille et celle source drain prouvent la non trivialité de ce comportement. Cette variation antisymétrique, qui a la même symétrie que le courant, indique un courant de spin induite par un phénomène de précession. Des simulations théoriques appuient également cette hypothèse: une combinaison de phénomènes d’accumulation de spin (induite par la polarisation en spin du courant) et des phénomènes de relaxation de spin (qui agissent contre la première catégorie) déterminent une précession du spin lors de son passage dans le nanotube

    Role of Disordered Precursor in L10 Phase Formation in FePt-Based Nanocomposite Magnet

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    In order to prove the usefulness of having a structurally disordered precursor to the formation of FePt L10 phase and to facilitate the co-existence of exchange coupled hard and soft magnetic phases with optimized magnetic properties in various conditions of annealing, a Fe-Pt-Zr-B melt spun alloy has been synthesized and detailed structural and magnetic investigations have been undertaken to probe its phase evolution during annealing. The dynamics of formation of the hard magnetic L10 phase during the gradual disorder–order phase transformation has been monitored by using a complex combination of X-ray diffraction methods and 57Fe Mössbauer spectroscopy methods, over a wide range of annealing temperatures. Multiple phases co-existing in the annealed sample microstructures, observed in XRD, have been reconfirmed by the Mössbauer spectra analysis and, moreover, accurate quantitative data have been acquired in what concerns the relative abundance of each of the observed crystalline phases in every stage of annealing. It is shown that the formation of the hard magnetic phase, emerging from the chemically disordered precursor, is gradual and occurs via complex mechanisms, involving the presence of a disordered Fe-Zr-B-rich intergranular region which contributes to an increase in the abundance of the L10 phase for higher annealing temperatures. Magnetic measurements have confirmed the good performances of these alloys in terms of coercivity and remanence. These results contribute to the development of these alloys as the next generation of rare earth, free permanent magnets

    Temperature-Dependent Phase Evolution in FePt-Based Nanocomposite Multiple-Phased Magnetic Alloys

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    A quaternary Fe&ndash;Pt&ndash;Nb&ndash;B alloy has been fabricated by the melt spinning method with the purpose of the formation of crystallographically coherent multiple magnetic phases, emerging from the same metastable precursor, as well as to investigate the phase interactions and the influence of their coupling on magnetic performances. For this purpose, extended structural and magnetic investigations were undertaken by making use of X-ray diffraction, transmission electron microscopy, and 57Fe M&ouml;ssbauer spectroscopy, as well as magnetic measurements using SQUID magnetometry. It was documented that intermediate metastable phases formed during primary crystallization, in intermediate stages of annealing, and a growth-dominated mode was encountered for the secondary crystallization stage upon annealing at 700 &deg;C and 800 &deg;C where fcc Fe3Pt and fct Fe2B polycrystalline were formed. The M&ouml;ssbauer investigations have documented rigorously the hyperfine parameters of each of the observed phases. The fcc A1 FePt phase was shown to exhibit a peculiar ferromagnetic transition, and this transition has been proven to occur gradually between 300 K and 77 K. The magnetic measurements allowed us to identify the annealing at 700 &deg;C as optimal for obtaining good magnetic features. Coercive field dependence shows similarities to the random anisotropy model for samples annealed at 500 &deg;C to 700 &deg;C which are nanocrystalline. These results show good perspectives for use in applications where different magnetic states are required at different operating temperatures
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