What factors are associated with recent intimate partner violence? findings from the WHO multi-country study on women's health and domestic violence

<p>Abstract</p> <p>Background</p> <p>Intimate partner violence (IPV) against women is a global public health and human rights concern. Despite a growing body of research into risk factors for IPV, methodological differences limit the extent to which comparisons can be made between studies. We used data from ten countries included in the WHO Multi-country Study on Women's Health and Domestic Violence to identify factors that are consistently associated with abuse across sites, in order to inform the design of IPV prevention programs.</p> <p>Methods</p> <p>Standardised population-based household surveys were done between 2000 and 2003. One woman aged 15-49 years was randomly selected from each sampled household. Those who had ever had a male partner were asked about their experiences of physically and sexually violent acts. We performed multivariate logistic regression to identify predictors of physical and/or sexual partner violence within the past 12 months.</p> <p>Results</p> <p>Despite wide variations in the prevalence of IPV, many factors affected IPV risk similarly across sites. Secondary education, high SES, and formal marriage offered protection, while alcohol abuse, cohabitation, young age, attitudes supportive of wife beating, having outside sexual partners, experiencing childhood abuse, growing up with domestic violence, and experiencing or perpetrating other forms of violence in adulthood, increased the risk of IPV. The strength of the association was greatest when both the woman and her partner had the risk factor.</p> <p>Conclusions</p> <p>IPV prevention programs should increase focus on transforming gender norms and attitudes, addressing childhood abuse, and reducing harmful drinking. Development initiatives to improve access to education for girls and boys may also have an important role in violence prevention.</p

Botulinum Neurotoxin D Uses Synaptic Vesicle Protein SV2 and Gangliosides as Receptors

Botulinum neurotoxins (BoNTs) include seven bacterial toxins (BoNT/A-G) that target presynaptic terminals and act as proteases cleaving proteins required for synaptic vesicle exocytosis. Here we identified synaptic vesicle protein SV2 as the protein receptor for BoNT/D. BoNT/D enters cultured hippocampal neurons via synaptic vesicle recycling and can bind SV2 in brain detergent extracts. BoNT/D failed to bind and enter neurons lacking SV2, which can be rescued by expressing one of the three SV2 isoforms (SV2A/B/C). Localization of SV2 on plasma membranes mediated BoNT/D binding in both neurons and HEK293 cells. Furthermore, chimeric receptors containing the binding sites for BoNT/A and E, two other BoNTs that use SV2 as receptors, failed to mediate the entry of BoNT/D suggesting that BoNT/D binds SV2 via a mechanism distinct from BoNT/A and E. Finally, we demonstrated that gangliosides are essential for the binding and entry of BoNT/D into neurons and for its toxicity in vivo, supporting a double-receptor model for this toxin

Multiple scattering effects on the EXAFS of Ge nanocrystals

We present a detailed extended x-ray absorption fine structure (EXAFS) spectroscopy study on the influence of multiple scattering effects on the analysis of bulk polycrystalline Ge (c-Ge) and of four Ge nanocrystal (NC) distributions with mean sizes from 4 to 9 nm. A complete description of the EXAFS signal up to the third shell of nearest neighbours for both c-Ge and Ge NCs is only achieved by including at least two double scattering and one triple scattering path. Unlike reports for bulk semiconductors and Ge-Si quantum dots, our results show that including only the most prominent double scattering path is insufficient for accurately ascertaining the structural parameters of the second and third shells, leading to unphysically small coordination numbers for the NCs. The same is observed when no multiple scattering paths are taken into account. The size dependence of the interatomic distance distributions up to the third shell of nearest neighbours has been determined for the first time. A greater reduction in coordination numbers and higher structural disorder were observed for the outer shells, reflecting the increase of the surface-to-volume ratio and reinforcing the presence of an amorphous Ge layer between the SiO2 matrix and the NCs. © 2008, Institute of Physic

Atomic-scale structure of Ga1-xInxP alloys measured with extended x-ray absorption fine structure spectroscopy.

Extended x-ray absorption fine structure spectroscopy was used to measure the interatomic distance distributions of the first three nearest-neighbor (NN) shells around Ga and In atoms in Ga1-xInxP. The first NN shell has a composition-dependent bimodal distance distribution with a relaxation parameter of epsilon= 0.80 +/-0.04 similar to other III-V ternary alloys. The second NN shell distance distribution remains multimodal, corresponding to the three different cation-cation pairs but is closer to the virtual-crystal approximation (VCA). The third NN shell mean distance is well approximated by the VCA although the distribution is significantly broadened. Predictive model calculations are discussed in detail where good agreement with experimental results is found. Like in Ga1-xInxAs, lattice mismatch is accommodated in Ga1-xInxP by both bond-length and bond-angle relaxations although primarily via the latter. © 2008, American Physical Societ

Anisotropic vibrations in crystalline and amorphous InP.

The temperature-dependent evolution of atomic vibrations in crystalline and amorphous InP has been studied using extended x-ray absorption fine-structure (EXAFS) spectroscopy. Measurements were performed at the In K edge for temperatures in the range of 20-295 K. In crystalline InP, the first nearest-neighbor (NN) EXAFS Debye-Waller factor, representative of the correlated mean-square relative displacement (MSRD) parallel to the bond direction, is considerably smaller than the uncorrelated mean-square displacement (MSD) determined from x-ray diffraction measurements. In contrast, the MSRD perpendicular to the bond direction agrees well with the MSD. This clearly demonstrates that vibrations of two neighboring atoms relative to each other are strongly reduced along the bond direction but are unhindered perpendicular to it, consistent with the well-known behavior of III-V semiconductors where bond bending is energetically favored over bond stretching. With increasing interatomic distance, the correlation of atomic motion quickly vanishes as manifested by increased EXAFS Debye-Waller factors. For the third NN shell the value closely approaches the MSD demonstrating the nearly uncorrelated motion of atoms only three shells apart. In the amorphous phase, only information about the first NN shell is accessible although the latter is now comprised of both P and In atoms. The EXAFS Debye-Waller factors are significantly higher than in the crystalline phase but exhibit a very similar temperature dependence. This results from strongly increased structural disorder in the amorphous phase whereas the thermally induced disorder is very similar to that in crystalline InP. A correlated Einstein model was fitted to the Debye-Waller factors yielding Einstein temperatures that vary as functions of the vibrational phase difference and reduced mass of the atomic pair, and represent a measure of the strength and thermal evolution of the corresponding relative vibrations. © 2009, American Physical Societ

Temperature-dependent EXAFS analysis of embedded Pt nanocrystals.

The vibrational and thermal properties of embedded Pt nanocrystals (NCs) have been investigated with temperature-dependent extended x-ray absorption fine structure (EXAFS) spectroscopy. NCs of diameter 1.8-7.4 nm produced by ion implantation in amorphous SiO2 were analysed over the temperature range 20-295 K. An increase in Einstein temperature (similar to 194 K) relative to that of a Pt standard (similar to 179 K) was evident for the smallest NCs while those larger than similar to 2.0 nm exhibited values comparable to bulk material. Similarly, the thermal expansion of interatomic distances was lowest for small NCs. While the amorphous SiO2 matrix restricted the thermal expansion of interatomic distances, it did not have a significant influence on the mean vibrational frequency of embedded Pt NCs. Instead, the latter was governed by finite-size effects or, specifically, capillary pressure. © 2009, Institute of Physic

Structural and vibrational properties of Co nanoparticles formed by ion implantation.

We report on the structural and vibrational properties of Co nanoparticles formed by ion implantation and thermal annealing in amorphous silica. The evolution of the nanoparticle size, phase, and structural parameters were determined as a function of the formation conditions using transmission electron microscopy, small-angle x-ray scattering, and x-ray absorption spectroscopy. The implantation fluence and annealing temperature governed the spherical nanoparticle size and phase. To determine the latter, x-ray absorption near-edge structure analysis was used to quantify the hexagonal close packed, face-centered cubic and oxide fractions. The structural properties were characterized by extended x-ray absorption fine structure spectroscopy (EXAFS) and finite-size effects were readily apparent. With a decrease in nanoparticle size, an increase in structural disorder and a decrease in both coordination number and bondlength were observed as consistent with the non-negligible surface-area-to-volume ratio characteristic of nanoparticles. The surface tension of Co nanoparticles calculated using a liquid drop model was more than twice that of bulk material. The size-dependent vibrational properties were probed with temperature-dependent EXAFS measurements. Using a correlated anharmonic Einstein model and thermodynamic perturbation theory, Einstein temperatures for both nanoparticles and bulk material were determined. Compared to bulk Co, the mean vibrational frequency of the smallest nanoparticles was reduced as attributed to a greater influence of loosely bonded, undercoordinated surface atoms relative to the effect of capillary pressure generated by surface curvature. © 2010, American Institute of Physic

Influence of annealing conditions on the growth and structure of embedded Pt nanocrystals.

The growth and structure of Pt nanocrystals (NCs) formed by ion implantation in a-SiO2 has been investigated as a function of the annealing conditions. Transmission electron microscopy and small-angle x-ray scattering measurements demonstrate that the annealing ambient has a significant influence on NC size. Samples annealed in either Ar, O-2, or forming gas (95% N-2: 5% H-2) at temperatures ranging from 500 degrees C-1300 degrees C form spherical NCs with mean diameters ranging from 1-14 nm. For a given temperature, annealing in Ar yields the smallest NCs. O-2 and forming gas ambients produce NCs of comparable size though the latter induces H chemisorption at 1100 degrees C and above, as verified with x-ray absorption spectroscopy. This H intake is accompanied by a bond-length expansion and increased structural disorder in NCs of diameter >3 nm. © 2009, American Institute of Physic

Size-dependent characterization of embedded Ge nanocrystals: structural and thermal properties.

A combination of conventional and synchrotron-based techniques has been used to characterize the size-dependent structural and thermal properties of Ge nanocrystals (NCs) embedded in a silica (a-SiO2) matrix. Ge NC size distributions with four different diameters ranging from 4.0 to 9.0 nm were produced by ion implantation and thermal annealing as characterized with small-angle x-ray scattering and transmission electron microscopy. The NCs were well represented by the superposition of bulklike crystalline and amorphous environments, suggesting the formation of an amorphous layer separating the crystalline NC core and the a-SiO2 matrix. The amorphous fraction was quantified with x-ray-absorption near-edge spectroscopy and increased as the NC diameter decreased, consistent with the increase in surface-to-volume ratio. The structural parameters of the first three nearest-neighbor shells were determined with extended x-ray-absorption fine-structure (EXAFS) spectroscopy and evolved linearly with inverse NC diameter. Specifically, increases in total disorder, interatomic distance, and the asymmetry in the distribution of distances were observed as the NC size decreased, demonstrating that finite-size effects govern the structural properties of embedded Ge NCs. Temperature-dependent EXAFS measurements in the range of 15-300 K were employed to probe the mean vibrational frequency and the variation of the interatomic distance distribution (mean value, variance, and asymmetry) with temperature for all NC distributions. A clear trend of increased stiffness (higher vibrational frequency) and decreased thermal expansion with decreasing NC size was evident, confirming the close relationship between the variation of structural and thermal/vibrational properties with size for embedded Ge NCs. The increase in surface-to-volume ratio and the presence of an amorphous Ge layer separating the matrix and crystalline NC core are identified as the main factors responsible for the observed behavior, with the surrounding a-SiO2 matrix also contributing to a lesser extent. Such results are compared to previous reports and discussed in terms of the influence of the surface-to-volume ratio in objects of nanometer dimensions. © 2008, American Physical Societ

fcc-hcp phase transformation in Co nanoparticles induced by swift heavy-ion irradiation.

We demonstrate a face-centered cubic (fcc) to hexagonally close-packed (hcp) phase transformation in spherical Co nanoparticles achieved via swift heavy-ion irradiation. Co nanoparticles of mean diameter 13.2 nm and fcc phase were first formed in amorphous SiO2 by ion implantation and thermal annealing and then irradiated at room temperature with 9-185 MeV Au ions. The crystallographic phase was identified with x-ray absorption spectroscopy and electron diffraction and quantified, as functions of the irradiation energy and fluence, with the former. The transformation was complete at low fluence prior to any change in nanoparticle shape or size and was governed by electronic stopping. A direct-impact mechanism was identified with the transformation interaction cross-section correlated with that of a molten ion track in amorphous SiO2. We suggest the shear stress resulting from the rapid thermal expansion about an ion track in amorphous SiO2 was sufficient to initiate the fcc-to-hcp phase transformation in the Co nanoparticles. © 2009, American Physical Societ