830 research outputs found

    The psychological selection profile for civil-military coordination officers in peace-support operations: The results of field research in the Sudan

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    The introduction of a multidimensional approach towards peace missions in complex emergencies emphasises the importance of coordination between the military and humanitarian components at all levels of interaction. Cooperation and coordination between the military and humanitarian components are critical in achieving a common goal for these operations: to alleviate suffering and prevent loss of life. The challenge of finding suitable personnel who can develop, enhance and sustain effective working relationships and overcome the potential for conflict in civil-military coordination, has not been addressed in practice and research. The military needs to identify personnel who, firstly, conform to the generic psychological peacekeeping profile and secondly, portray the knowledge, skills, and abilities to perform the coordination function satisfactorily. Due to the absence of a psychological selection profile for civil-military coordination officers, the selection and screening of competent military personnel members remain a challenge. Through this descriptive field research (conducted in the Sudan), a psychological selection profile for civil-military coordination officers is developed and defined. The theoretical foundation and primary data from field research are integrated into a job competency model for civil-military coordination officers, useful for future selection purposes. The results of this research are presented as a model of provisional selection criteria for civil-military coordination officers. Preliminary predictor and criterion data were collected to describe the relationship between selection measures and performance ratings of job incumbents. Areas for further research are discussed. Are these events indicative of a militarised SADC strategic culture as opposed to the declared pacifist preferences to resolve conflicts

    Correlated Photon Emission from a Single II-VI Quantum Dot

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    We report correlation and cross-correlation measurements of photons emitted under continuous wave excitation by a single II-VI quantum dot (QD) grown by molecular-beam epitaxy. A standard technique of microphotoluminescence combined with an ultrafast photon correlation set-up allowed us to see an antibunching effect on photons emitted by excitons recombining in a single CdTe/ZnTe QD, as well as cross-correlation within the biexciton (X2X_{2})-exciton (XX) radiative cascade from the same dot. Fast microchannel plate photomultipliers and a time-correlated single photon module gave us an overall temporal resolution of 140 ps better than the typical exciton lifetime in II-VI QDs of about 250ps.Comment: 4 pages, 3 figures, to appear in Appl. Phys. Let

    Use of telemedicine in the postoperative assessment of proctological patients: a case-control study

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    Background: Telemedicine is emerging as an easy way to communicate between patients and surgeons. Use of telemedicine increased during the coronavirus disease 2019 (COVID-19) pandemic. WhatsApp is one of the most common smartphone applications for user-friendly telemedicine. The aim of this study was to evaluate patient perception of health quality and positive outcomes using a diary sent by the patient to the surgeon via WhatsApp during the first post-discharge week after proctologic surgery. Methods: Ninety-eight patients discharged after proctologic surgery at the Israelite Hospital of Rome and the AOU Policlinico Umberto I of Rome in 1 January-31 December 2019 were divided into two groups: the WhatsApp group (group A), (n = 36) and the no WhatsApp group (group B) (n = 62). Group A patients received a protocol to follow for the day-by-day diary during the first post-discharge week and sending it by WhatsApp to the surgeon. Group B patients only received recommendations at discharge. The tool's usefulness was assessed by a questionnaire one month after the intervention. Results: The two groups were homogeneous for age, sex, schooling, employment, and proctologic pathology. Group A patients had less difficulty keeping a diary (p < 0.0001). Group A patients had the perception of better follow-up post-discharge (p = 0.002). The use of the diary sent by WhatsApp significantly improved the perception of positive post-intervention outcomes (p = 0.007). WhatsApp was the only independent predictor of perception of post-surgical positive outcomes (odds ratio = 4.06; 95% CI 1.35-12.24; p = 0.01). Conclusions: The use of WhatsApp in the post-discharge period improves the lifestyle quality of the patients and their perception of the safety and quality of care received

    Non-stationary dynamo & magnetospheric accretion processes of the classical T Tauri star V2129 Oph

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    We report here the first results of a multi-wavelength campaign focussing on magnetospheric accretion processes of the classical TTauri star (cTTS) V2129Oph. In this paper, we present spectropolarimetric observations collected in 2009 July with ESPaDOnS at the Canada-France-Hawaii Telescope (CFHT). Circularly polarised Zeeman signatures are clearly detected, both in photospheric absorption and accretion-powered emission lines, from time-series of which we reconstruct new maps of the magnetic field, photospheric brightness and accretion-powered emission at the surface of V2129Oph using our newest tomographic imaging tool - to be compared with those derived from our old 2005 June data set, reanalyzed in the exact same way. We find that in 2009 July, V2129Oph hosts octupolar & dipolar field components of about 2.1 & 0.9kG respectively, both tilted by about 20deg with respect to the rotation axis; we conclude that the large-scale magnetic topology changed significantly since 2005 June (when the octupole and dipole components were about 1.5 and 3 times weaker respectively), demonstrating that the field of V2129Oph is generated by a non-stationary dynamo. We also show that V2129Oph features a dark photospheric spot and a localised area of accretion-powered emission, both close to the main surface magnetic region (hosting fields of up to about 4kG in 2009 July). We finally obtain that the surface shear of V2129Oph is about half as strong as solar. From the fluxes of accretion-powered emission lines, we estimate that the observed average logarithmic accretion rate (in Msun/yr) at the surface of V2129Oph is -9.2+-0.3 at both epochs, peaking at -9.0 at magnetic maximum. It implies in particular that the radius at which the magnetic field of V2129Oph truncates the inner accretion disc is 0.93x and 0.50x the corotation radius in 2009 July and 2005 June respectively.Comment: MNRAS in press - 16 pages, 9 figure

    Contact angles mediate equilibrium fractionation between soil water and water vapor

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    Soil water potential is a function of grain size, adhesion and cohesion energy. The mechanical equilibrium between the interfacial free energies between water-gas, water-solid and solid-gas, leads to a particular contact angle at the three phase boundary water-solid-gas. The contact angle of the solid-soil affects the water retention in soils. Contact angles >0 lead to a shift of the water retention curve to simulating a coarser soil texture. Thus, a certain amount of water is stronger bound in a soil with a low contact angle compared to the same soil with a high contact angle. The relationship between the contact angle and the fractionation of water stable isotopes between soil water and water vapor has yet not been studied. We present a simple laboratory experiment with soil samples ranging from sand to silt to clay. Two subsamples were hydrophobized (or treated with) using dichlorodimethylsilane to produce different contact angles. Subsamples were transferred into Ziploc bags spiked with water of known isotopic composition and the headspace filled with dry air. After equilibration (at least 24h) the headspace was measured for its isotopic signature with a Laserspectrometer. Soil water potential was measured with a soil water potential meter and the contact angle determined with the Wilhelmy-plate-method (WPM). The working hypothesis is that the equilibrium between water and water vapor depends on the matric potential. Having the same pore and the same water content water repellency affects the soil water potential. Therefore the hydrophobized soil will change the equilibrium fractionation between water and water vapor. Hence, the contact angle between adsorbed water and water vapor is related to isotope effects

    Improved genome editing in human cell lines using the CRISPR method

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    The Cas9/CRISPR system has become a popular choice for genome editing. In this system, binding of a single guide (sg) RNA to a cognate genomic sequence enables the Cas9 nuclease to induce a double-strand break at that locus. This break is next repaired by an error-prone mechanism, leading to mutation and gene disruption. In this study we describe a range of refinements of the method, including stable cell lines expressing Cas9, and a PCR based protocol for the generation of the sgRNA. We also describe a simple methodology that allows both elimination of Cas9 from cells after gene disruption and re-introduction of the disrupted gene. This advance enables easy assessment of the off target effects associated with gene disruption, as well as phenotype-based structure-function analysis. In our study, we used the Fan1 DNA repair gene as control in these experiments. Cas9/CRISPR-mediated Fan1 disruption occurred at frequencies of around 29%, and resulted in the anticipated spectrum of genotoxin hypersensitivity, which was rescued by re-introduction of Fan1

    Theory of Magnetic Anisotropy in III_{1-x}Mn_{x}V Ferromagnets

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    We present a theory of magnetic anisotropy in III1xMnxV{\rm III}_{1-x}{\rm Mn}_{x}{\rm V} diluted magnetic semiconductors with carrier-induced ferromagnetism. The theory is based on four and six band envelope functions models for the valence band holes and a mean-field treatment of their exchange interactions with Mn++{\rm Mn}^{++} ions. We find that easy-axis reorientations can occur as a function of temperature, carrier density pp, and strain. The magnetic anisotropy in strain-free samples is predicted to have a p5/3p^{5/3} hole-density dependence at small pp, a p1p^{-1} dependence at large pp, and remarkably large values at intermediate densities. An explicit expression, valid at small pp, is given for the uniaxial contribution to the magnetic anisotropy due to unrelaxed epitaxial growth lattice-matching strains. Results of our numerical simulations are in agreement with magnetic anisotropy measurements on samples with both compressive and tensile strains. We predict that decreasing the hole density in current samples will lower the ferromagnetic transition temperature, but will increase the magnetic anisotropy energy and the coercivity.Comment: 15 pages, 15 figure

    Oscillating magnetoresistance in diluted magnetic semiconductor barrier structures

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    Ballistic spin polarized transport through diluted magnetic semiconductor (DMS) single and double barrier structures is investigated theoretically using a two-component model. The tunneling magnetoresistance (TMR) of the system exhibits oscillating behavior when the magnetic field are varied. An interesting beat pattern in the TMR and spin polarization is found for different NMS/DMS double barrier structures which arises from an interplay between the spin-up and spin-down electron channels which are splitted by the s-d exchange interaction.Comment: 4 pages, 6 figures, submitted to Phys. Rev.

    Landau Level Crossings and Extended-State Mapping in Magnetic Two-dimensional Electron Gases

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    We present longitudinal and Hall magneto-resistance measurements of a ``magnetic'' two-dimensional electron gas (2DEG) formed in modulation-doped Zn1xy_{1-x-y}Cdx_{x}Mny_{y}Se quantum wells. The electron spin splitting is temperature and magnetic field dependent, resulting in striking features as Landau levels of opposite spin cross near the Fermi level. Magnetization measurements on the same sample probe the total density of states and Fermi energy, allowing us to fit the transport data using a model involving extended states centered at each Landau level and two-channel conduction for spin-up and spin-down electrons. A mapping of the extended states over the whole quantum Hall effect regime shows no floating of extended states as Landau levels cross near the Fermi level.Comment: 10 pages, 4 figures, submitted to Phys. Rev.
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