874 research outputs found

    Electric field control of the magnetic chiralities in ferroaxial multiferroic RbFe(MoO4)2

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    The coupling of magnetic chiralities to the ferroelectric polarisation in multiferroic RbFe(MoO4_4)2_2 is investigated by neutron spherical polarimetry. Because of the axiality of the crystal structure below TcT_\textrm{c} = 190 K, helicity and triangular chirality are symmetric-exchange coupled, explaining the onset of the ferroelectricity in this proper-screw magnetic structure - a mechanism that can be generalised to other systems with "ferroaxial" distortions in the crystal structure. With an applied electric field we demonstrate control of the chiralities in both structural domains simultaneously.Comment: 5 pages, 4 figure

    Electric field control of multiferroic domains in Ni3_3V2_2O8_8 imaged by X-ray polarization enhanced topography

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    The magnetic structure of multiferroic Ni3_3V2_2O8_8 has been investigated using non-resonant X-ray magnetic scattering. Incident circularly polarized X-rays combined with full polarization analysis of the scattered beam is shown to yield high sensitivity to the components of the cycloidal magnetic order, including their relative phases. New information on the magnetic structure in the ferroelectric phase is obtained, where it is found that the magnetic moments on the "cross-tie" sites are quenched relative to those on the "spine" sites. This implies that the onset of ferroelectricity is associated mainly with spine site magnetic order. We also demonstrate that our technique enables the imaging of multiferroic domains through polarization enhanced topography. This approach is used to image the domains as the sample is cycled by an electric field through its hysteresis loop, revealing the gradual switching of domains without nucleation.Comment: 9 pages, 6 figure

    Somatosensory-Evoked Early Sharp Waves in the Neonatal Rat Hippocampus

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    The developing entorhinal–hippocampal system is embedded within a large-scale bottom-up network, where spontaneous myoclonic movements, presumably via somatosensory feedback, trigger hippocampal early sharp waves (eSPWs). The hypothesis, that somatosensory feedback links myoclonic movements with eSPWs, implies that direct somatosensory stimulation should also be capable of evoking eSPWs. In this study, we examined hippocampal responses to electrical stimulation of the somatosensory periphery in urethane-anesthetized, immobilized neonatal rat pups using silicone probe recordings. We found that somatosensory stimulation in ~33% of the trials evoked local field potential (LFP) and multiple unit activity (MUA) responses identical to spontaneous eSPWs. The somatosensory-evoked eSPWs were delayed from the stimulus, on average, by 188 ms. Both spontaneous and somatosensory-evoked eSPWs (i) had similar amplitude of ~0.5 mV and half-duration of ~40 ms, (ii) had similar current-source density (CSD) profiles, with current sinks in CA1 strata radiatum, lacunosum-moleculare and DG molecular layer and (iii) were associated with MUA increase in CA1 and DG. Our results indicate that eSPWs can be triggered by direct somatosensory stimulations and support the hypothesis that sensory feedback from movements is involved in the association of eSPWs with myoclonic movements in neonatal rats

    Caregiver burden on sexual intimacy and marital satisfaction

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    SUMMARY Objective: This study investigates affective and sexual dimensions in partners involved as caregivers of Alzheimer dementia (AD) subjects. A negative correlation between burden of the caregiver and sexual-affective quality of life was assumed. Design and methods: Hundred participants with AD partner (33 male, 67 female), aged between 55 and 85 years were recruited and data were collected from the Caregiver Burden Inventory scale and a semi-structured interview that included demographic information, medical history, relationship and sexual satisfaction, and current sexual function. AD group was compared with a control group (CG) (N ¼ 100) matched for age, sex, education and marital status on measures of the semi-structured interview. Data were analysed using frequency count, univariate analysis (chi-squared and ANOVA) and bivariate correlation. Results: The findings revealed that mean burden level was 31.59 (SD 19.51). A difference between experimental and CGs was found for sexual and affective marital satisfaction (p < 0.05). The same variables showed a rather negative correlation with total burden levels (r ¼ )0.374, p < 0.001; r ¼ )0.448, p < 0.001). What's known Alzheimer dementia and the global impairment of intellectual function, as well as its physiological correlates, have strong influence on the quality of life with the consequent need of assistance which could determine a high burden level in the caregiver. The attendant cognitive changes that occur in the Alzheimer patient present many, often conflicting, challenges to a couple's sexual functioning 2,

    Circularly polarised X-rays as a probe of non-collinear magnetic order in multiferroic TbMnO3

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    Non-resonant X-ray magnetic scattering has been used to study the magnetic structure of multiferroic TbMnO3 in its ferroelectric phase. Circularly polarized X-rays were combined with a full polarization analysis of the scattered beam to reveal important new information on the magnetic structure of this canonical multiferroic. An applied electric field is shown to create a magnetic nearly mono-domain state in which the cylcoidal order on the Mn sublattice rotates either clockwise or counter-clockwise depending on the sign of the field. It is demonstrated how this technique provides sensitivity to the absolute sense of rotation of the Mn moments, and to components of the ordering on the Tb sublattice and phase shifts that earlier neutron diffraction experiments could not resolve.Comment: 4 pages, 3 figure

    Electrophysiological Measurements and Analysis of Nociception in Human Infants

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    Pain is an unpleasant sensory and emotional experience. Since infants cannot verbally report their experiences, current methods of pain assessment are based on behavioural and physiological body reactions, such as crying, body movements or changes in facial expression. While these measures demonstrate that infants mount a response following noxious stimulation, they are limited: they are based on activation of subcortical somatic and autonomic motor pathways that may not be reliably linked to central sensory processing in the brain. Knowledge of how the central nervous system responds to noxious events could provide an insight to how nociceptive information and pain is processed in newborns

    Femtoscale magnetically induced lattice distortions in multiferroic TbMnO3

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    Magneto-electric multiferroics exemplified by TbMnO3 possess both magnetic and ferroelectric long-range order. The magnetic order is mostly understood, whereas the nature of the ferroelectricity has remained more elusive. Competing models proposed to explain the ferroelectricity are associated respectively with charge transfer and ionic displacements. Exploiting the magneto-electric coupling, we use an electric field to produce a single magnetic domain state, and a magnetic field to induce ionic displacements. Under these conditions, interference charge-magnetic X-ray scattering arises, encoding the amplitude and phase of the displacements. When combined with a theoretical analysis, our data allow us to resolve the ionic displacements at the femtoscale, and show that such displacements make a significant contribution to the zero-field ferroelectric moment.Comment: This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science VOL 333, (2011), doi:10.1126/science.120808

    Development and psychometric testing of a theory-based tool to measure self-care in diabetes patients: the Self-Care of Diabetes Inventory

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    Background: Self-care is essential for patients with diabetes mellitus. Both clinicians and researchers must be able to assess the quality of that self-care. Available tools have various limitations and none are theoretically based. The aims of this study were to develop and to test the psychometric properties of a new instrument based on the middle range-theory of self-care of chronic illness: the Self-Care of Diabetes Inventory (SCODI). Methods: Forty SCODI items (5 point Likert type scale) were developed based on clinical recommendations and grouped into 4 dimensions: self-care maintenance, self-care monitoring, self-care management and self-care confidence based on the theory. Content validity was assessed by a multidisciplinary panel of experts. A multi-centre cross-sectional study was conducted in a consecutive sample of 200 type 1 and type 2 diabetes patients. Dimensionality was evaluated by exploratory factor analyses. Multidimensional model based reliability was estimated for each scale. Multiple regression models estimating associations between SCODI scores and glycated haemoglobin (HbA1c), body mass index, and diabetes complications, were used for construct validity. Results: Content validity ratio was 100%. A multidimensional structure emerged for the 4 scales. Multidimensional model-based reliabilities were between 0.81 (maintenance) and 0.89 (confidence). Significant associations were found between self-care maintenance and HbA1c (p = 0.02) and between self-care monitoring and diabetes complications (p = 0.04). Self-care management was associated with BMI (p = 0.004) and diabetes complications (p = 0.03). Self-care confidence was a significant predictor of self-care maintenance, monitoring and management (all p &lt; 0.0001). Conclusion: The SCODI is a valid and reliable theoretically-grounded tool to measure self-care in type 1 and type 2 DM patients

    Semantic technologies for the production and publication of open data in ACI - Automobile club d’Italia

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    Semantic technologies combine knowledge representation techniques with artificial intelligence in order to achieve a more effective management of enterprise knowledge bases, thanks to the separation of the conceptual level of the applications from the logical and physical ones, and to the automatic reasoning services they deploy for data access and control. In this context, Ontology-based Data Management (OBDM) [3] has consolidated itself as a paradigm for data integration and governance, based on a three-tier architecture: the ontology, the data sources, and the mappings, which declaratively link the ontology predicates to the data in the sources. In this talk1 we present a joint project by Sapienza University of Rome, the Automobile Club d’Italia (ACI), and OKKAM S.r.l.2, a spinoff of the University of Trento. The objectives of the project were the definition of an ontology of ACI’s Public Vehicle Register (PRA) and car tax domains, the development of an OBDM system to access the data through such ontology, and the creation of a web portal for the publication of ACI’s car parc data in Linked Open format
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