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We present a parton-level study of electro-weak production of vector-boson pairs at the Large Hadron Collider, establishing the sensitivity to a set of dimension-six operators in the ...Standard Model Effective Field Theory (SMEFT). Different final states are statistically combined, and we discuss how the orthogonality and interdependence of different analyses must be considered to obtain the most stringent constraints. The main novelties of our study are the inclusion of SMEFT effects in non-resonant diagrams and in irreducible QCD backgrounds, and an exhaustive template analysis of optimal observables for each operator and process considered. We also assess for the first time the sensitivity of vector-boson-scattering searches in semileptonic final states.
Abstract Introduction Suicidal ambivalence is increasingly understood as the result of the interplay of two conflicting motivational orientations, the wish to die (WTD) and wish to live (WTL). ...However, research is scarce regarding the nature of their relationship, their temporal structure, and their relevance in predicting suicidal desire. Methods Fifty psychosomatic/psychiatric inpatients (17 reporting suicide attempts) took part in an intensive longitudinal design with 10 signal‐contingent prompts per day over 10 days; assessing WTD, WTL, and suicidal desire. We calculated mean values and variability of WTD, WTL, suicidal ambivalence, and suicidal desire and tested mixed‐effects models of suicidal desire. Results The mean number of answered prompts was 40.98 (SD = 21.68). Repeated‐measures correlation of WTD and WTL was r = −0.60. Patients with a history of suicide attempts reported higher WTD, lower WTL, more suicidal ambivalence, stronger suicidal desire, and showed higher variability in all constructs. At the same assessment, WTD was the strongest statistical predictor of suicidal desire. Only WTL and the interaction of WTD and WTL predicted suicidal desire prospectively. Conclusion Wish to die and WTL are likely two distinct (although correlated) constructs that should not be reduced to a single ambivalence score. A stronger focus on WTL holds potential for suicide research and practice.
•Structural and magnetic properties of (Ni1−xCox)Cr2O4 (size from TEM: 50 – 100 nm) were presented using chemical co-precipitation techniques.•The values of TC determined for both NiCr2O4 and CoCr2O4 ...was higher than the reported values with noticeable increase upon substitution of Ni by Co.•For the case of (Ni0.5Co0.5)Cr2O4, high coercivity of 3.6 T and shifting of the M-H loop under field cooling condition was observed.•X-ray photoelectron spectroscopy (XPS) of (Ni0.5Co0.5)Cr2O4 suggests Ni and Co are in 2+ oxidation state and Cr in 3+ oxidation state.•EXAFS measurements confirmed that no redistribution of A and B site cations occur at low temperatures by doping Co2+ at A sites.
It is of interest to study the magneto-structural coupling in geometrically frustrated antiferromagnets, where structural distortion elevates the ground state degeneracy, leading to a long-range magnetic order. In this regard a cubic spinel compound of the form AB2O4 is currently drawing much attention, where A refers to tetrahedral and B to octahedral sites. In the particular case of NiCr2O4 the material undergoes several structural phase transitions associated with the magnetic ordering. It is therefore necessary to study the magnetic behaviour of NiCr2O4 by substituting either A or B sites, or both systematically with suitable cations. The current work therefore aims at the modification of magnetic properties of NiCr2O4 by doping with Co2+ at A sites. In order to achieve the afore mentioned, (Ni1−xCox)Cr2O4 (0 ≤ x ≤ 1) were prepared using chemical co-precipitation techniques. X–ray diffraction (XRD) results indicate that the samples are in the expected phase without any trace of Cr2O3 impurities after calcination. Transmission electron microcopy (TEM) analyses of these samples show that the particles are mostly bi-pyramidal in shape, with sizes ranging from 50 nm to 100 nm. In the present study the ferrimagnetic transition temperatures (TC) of the various samples were determined utilizing magnetization as function of temperature measurements. TC for NiCr2O4 and CoCr2O4 was determined to be 82.4 ± 0.8 K and 99.5 ± 0.5 K, respectively. These values are higher than those previously reported in the literature for both these compounds. Substitution of Ni by Co, results in an increase in the TC, giving values of 89.2 ± 0.7 K and 90.6 ± 0.9 K for (Ni0.5Co0.5)Cr2O4 and (Ni0.25Co0.75)Cr2O4, respectively. The (Ni0.5Co0.5)Cr2O4 sample demonstrated a high coercivity of 3.6 ± 0.1 T and a shift in the hysteresis loop observed under field cooled measurement, not previously reported in literature. X–ray photoelectron spectroscopy (XPS) of (Ni0.5Co0.5)Cr2O4 suggests that the oxidation states of Ni and Co are 2+, while that of Cr is 3+. In order to investigate the local structure around the cations, low temperature extended x–ray absorption fine structure (EXAFS) measurements were performed. From EXAFS it is confirmed that no redistribution of A and B site cations occur at low temperatures. Present findings demonstrate that the magnetic properties of NiCr2O4 can easily and dramatically be modified by doping Co2+ at A sites.
We report here a real-time structural study of the synthesis of nanoparticles (NPs) capped with organic ligands. The present work focuses on the case of zinc oxide (ZnO) NPs capped with thiol ...(dodecanethiol and hexanethiol), which have attracted much attention due to their dual semiconductor and ferromagnetic properties. X-ray absorption spectroscopy (both XANES and EXAFS regions) and X-ray diffraction (XRD) measurements were carried out during the growth of the NPs to gain a deeper understanding of the kinetic of the growing process and the thiol addition. This is clearly important for tailoring the properties of these kind of systems. In a first step, it is found that while the NP’s growth occurs and reaches the maximum size in 2 min, the local structure around Zn atoms needs ∼20 min to be stabilized. In a second step, after adding the thiol, an initial fast adsorption of the thiol molecules takes place, followed by an slower process that ends with the stabilization of a core–shell structure.
Abstract
The results of a collaborative development activity aimed to the realization of multi-cell detectors based on monolithic SDD pixel technology will be described. Two kind of detection ...systems, skilled for the light lines at synchrotrons, have been brought to high levels of finalization and integration; a 64 cells detection system dedicated to absorption spectroscopy (XAFS) and a 32 cells detector for the X-ray microscopy (TwinMic). The main targets of this effort, led in a tight collaboration with the beam lines scientists, were large sensitive area, high rate capabilities, state of the art efficiency and energy resolution. The aim is to reduce the beam time demand for each single measurement while delivering a cutting edge analytical power.
All basic elements of those detection systems, from the detector’s design and production to the front-end and read-out electronics including the final engineering of the integrated system were customized to the specific use addressed.
Novel iron-doped aluminogermanate nanotubes were obtained using a single step, aqueous phase synthesis protocol. These nanotubes are isostructural with imogolite, a natural occurring nanofiber, but ...are obtained by-product free in substantially larger quantities with aluminum substitution levels around 1%. Increasing the Fe concentrations led to higher substitution levels but also to the co-precipitation of Fe (oxy)hydroxides.
The growth mechanisms of imogolite-like aluminogermanate nanotubes have been examined at various stages of their formation. The accurate determination of the nucleation stage was examined using a ...combination of local- (XAS at the Ge−K edge and 27Al NMR) and semilocal scale technique (in situ SAXS). For the first time, a model is proposed for the precursors of the nanotubular structure and consist in rooftile-shaped particles, up to 5 nm in size, with ca. 26% of Ge vacancies and varying curvatures. These precursors assemble to form short nanotubes/nanorings observed during the aging process. The final products are most probably obtained by an edge−edge assembly of these short nanotube segments.
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