Search

Abstract Background: There is a lack of knowledge about how persons with cerebral palsy (CP) perceive their ‘process of doing’ while performing everyday occupations. As described in the Model of the Process of Doing (MPoD), performing an occupation is a complex process consisting of six phases (generate idea, plan, initiate, enact, adjust, end) and time management. Aim: To collect the experiences of young adults with CP, classified at Manual Ability Classification System (MACS) level I or II, regarding how they perceive challenges in their occupational performance in relation to the different phases of the ‘process of doing’. Method: Semi-structured interviews were performed with ten participants with CP aged 19–30 years, MACS level I or II. The interview material was related to the MPoD phases using directed content analysis. Results: The participants’ descriptions of how they perceived their personal ‘process of doing’ showed problems in all MPoD phases. All participants experienced difficulties in one or more phases, but none had difficulties in all phases. Difficulties were more frequent in some phases than in others. Conclusion/Significance: To understand the complexity of doing everyday occupations in young adults with CP, there is a need to address all phases of the ‘process of doing’. [ABSTRACT FROM AUTHOR]

During the Late Pleistocene, several possibly endemic cingulate species, known mostly from isolated osteoderms, cara-pace fragments, and caudal tubes, coexisted in the Brazilian Intertropical Region. Here, we describe the osteoderm micro- structure of Pachyarmatherium brasiliense, as well as the glyptodonts Panochthus greslebini, Panochthus jaguaribensis and Glyptotherium sp., in order to provide additional species-diagnostic characters and shed light on their evolutionary relationships. Pachyarmatherium brasiliense lacks several derived features shared by glyptodonts and pampatheres, such as extensive bone remodeling, fibers arranged in large bundles, and relatively poorly developed layers of compact bone, thus supporting its exclusion from glyptodonts as suggested by a recent cladistic study. The osteoderm histology of P. greslebini resembles that of other species of Panochthus (e.g., Panochthus frenzelianus). By contrast, the presence of relatively thick layers of compact bone, the configuration and size of resorption areas, the absence of randomly oriented lateral fiber bundles, and the absence of an intermediary region between the compact and trabecular bone potentially support the exclusion of Panochthus jaguaribensis from the genus. Finally, osteoderms of the Brazilian specimens of Glyptodontinae share histological features with Glyptotherium floridanus, rather than Glyptodon, thus reinforcing their assignment to Glyptotherium. These results highlight the relevance of histological osteoderm characters in cingulate systematics, ands call for further and more comprehensive studies. [ABSTRACT FROM AUTHOR]

Landau phenomenological theory in combination with first-principles calculations was used to reveal the origin of the metamagnetic nature and the unusually strong dependence of the ordering temperature with doping of the Fe2P compound. We show that the magnetism of the two sublattices occupied by Fe atoms has an entwined codependency, which is strongly influenced by alloying. We furthermore demonstrate that a constrained disordered local moment approach combined with Monte Carlo simulations can only reproduce the experimental ordering temperatures in these technologically important prototype alloys for magnetocaloric refrigeration. [ABSTRACT FROM AUTHOR]

Based on first-principles calculations and kinetic Monte Carlo simulations, we design a realistic and practical codoping technique for increasing the concentration of Mn atoms in GaAs and realizing high Curie temperatures in (Ga,Mn)As. We found that using codoping of Li interstitial atoms during the crystal growth has two great advantages. First, due to lower formation energy of Li interstitials compared to Mn interstitials, Li prevents formation of unwanted Mn interstitials. Second, Li interstitials can be removed by using post-growth annealing at low temperatures. This codoping method offers a general strategy to go far beyond the solubility limit and it should be applicable also to other diluted magnetic semiconductor systems. [ABSTRACT FROM AUTHOR]

Purpose: To develop a method for isolated perfusion of the liver using radiological methods.Methods: Twenty-one pigs, weighing about 20 kg, were divided into three groups. By transjugular and transfemoral approaches two occlusion balloons were placed in the inferior vena cava cranial and caudal, respectively, to the origin of the hepatic veins. One occlusion balloon was placed transfemorally in the common hepatic artery. Another occlusion balloon was inserted in the main branch of the portal vein via the transjugular-transhepatic approach in 11 pigs (groups 1 and 2), and in 10 pigs (group 3) by a percutaneous transhepatic route. After inflation of the balloons, patency of the isolated liver circulation was evaluated by recirculation of 99Tcm-labelled human albumin during 30 min. Blood tests were obtained after 1, 3, 5, 10, 15, and 30 min to evaluate leakage from the liver to the systemic circulation.Results: Increasing leakage to the systemic circulation from the isolated liver circulation was observed in groups 1 and 2. In the third group the leakage was less than 10%.Conclusion: In an experimental animal model, isolated perfusion of the liver with minor leakage to the systemic circulation may be achieved using radiological methods. [ABSTRACT FROM AUTHOR]

Abstract Background Negative experiences of first childbirth increase risks for maternal postpartum depression and may negatively affect mothers' attitudes toward future pregnancies and choice of delivery method. Postpartum questionnaires assessing mothers' childbirth experiences are needed to aid in identifying mothers in need of support and counselling and in isolating areas of labour and birth management and care potentially in need of improvement. The aim of this study was to develop and evaluate a questionnaire for assessing different aspects of first-time mothers' childbirth experiences. Methods Childbirth domains were derived from literature searches, discussions with experienced midwives and interviews with first-time mothers. A draft version of the Childbirth Experience Questionnaire (CEQ) was pilot tested for face validity among 25 primiparous women. The revised questionnaire was mailed one month postpartum to 1177 primiparous women with a normal pregnancy and spontaneous onset of active labor and 920 returned evaluable questionnaires. Exploratory factor analysis using principal components analysis and promax rotation was performed to identify dimensions of the childbirth experience. Multitrait scaling analysis was performed to test scaling assumptions and reliability of scales. Discriminant validity was assessed by comparing scores from subgroups known to differ in childbirth experiences. Results Factor analysis of the 22 item questionnaire yielded four factors accounting for 54% of the variance. The dimensions were labelled Own capacity, Professional support, Perceived safety, and Participation. Multitrait scaling analysis confirmed the fit of the four-dimensional model and scaling success was achieved in all four sub-scales. The questionnaire showed good sensitivity with dimensions discriminating well between groups hypothesized to differ in experience of childbirth. Conclusion The CEQ measures important dimensions of the first childbirth experience and may be used to measure different aspects of maternal satisfaction with labour and birth.

The strong coupling between the crystal structure and magnetic state (ferromagnetic or helical antiferromagnetic) of FeMnP0.75Si0.25 is investigated using density functional theory in combination with atomistic spin dynamics. We find many competing energy minima for drastically different ferromagnetic and noncollinear magnetic configurations. We also find that the appearance of a helical spin-spiral magnetic structure at finite temperature is strongly related to one of the crystal structures reported for this material. Shorter Fe-Fe distances are found to lead to a destabilized ferromagnetic coupling, while out-of-plane Mn-Mn exchange interactions become negative with the shortening of the interatomic distances along the c axis, implying an antiferromagnetic coupling for the nearest-neighbor Mn-Mn interactions. The impact of the local dynamical correlations is also discussed. [ABSTRACT FROM AUTHOR]

The electronic, thermodynamical, and transport properties of ordered Fe3X (X=Al,Si) alloys are studied from first principles. We present here a unified approach to the phase stability, the estimate of the Curie temperature, the temperature dependence of sublattice magnetizations, magnon spectra, the spin-stiffnesses, and residual resistivities. An important feature of the present study is that all calculated physical properties are determined in the framework of the same first-principles electronic structure model combined with the effective Ising and Heisenberg Hamiltonians used for study of the thermodynamical properties of alloys. Curie temperatures, spin-stiffnesses, and magnon spectra are determined using the same calculated exchange integrals. Finally, the transport properties are calculated using the linear-response theory. Our theoretical estimates compare well with available experimental data. In particular, calculations predict (in agreement with experiment) the ordered D03 phase as the ground-state alloy structure, demonstrate that a correct relation of Curie temperatures of Fe3Al/Fe3Si alloys can be obtained only by going beyond a simple mean-field approximation, provide reasonable estimates of spin-stiffnesses, and give resistivities compatible with structural disorder observed in the experiment. Although the calculated temperature dependences of the Fe magnetization on different sublattices are similar, they nevertheless deviate more than in the experiment, and we discuss a possible origin. [ABSTRACT FROM AUTHOR]

Di-iron phosphide (Fe2P) is a parent system for a set of magnetocaloric materials. Although the magnetic ordering temperature (Tc = 215 K) of the stoichiometric composition is too low for room-temperature magnetic refrigeration, the partial replacement of P with B, Si, or As elements results in a steep increase in the magnetic ordering temperature. Doping leads to different equilibrium volumes and hexagonal axial ratios (c/a) within the same crystallographic phase over a wide concentration range. Here, using first principles theory, we decompose the change in the total magnetic exchange interaction upon doping into chemical and structural contributions, the latter including the c/a-ratio and volume effects. We demonstrate that for the investigated alloys the structural effect can be ascribed mainly to the decrease in the c/a ratio that strengthens the magnetic exchange interactions between the two Fe sublattices. [ABSTRACT FROM AUTHOR]

The half-metallic half-Heusler alloy NiMnSb is a promising candidate for applications in spintronic devices due to its low magnetic damping and its rich anisotropies. Here we use ferromagnetic resonance (FMR) measurements and calculations from first principles to investigate how the composition of the epitaxially grown NiMnSb influences the magnetodynamic properties of saturation magnetization Ms, Gilbert damping a, and exchange stiffness A. Ms and A are shown to have a maximum for stoichiometric composition, while the Gilbert damping is minimum. We find excellent quantitative agreement between theory and experiment for Ms and α. The calculated A shows the same trend as the experimental data but has a larger magnitude. In addition to the unique in-plane anisotropy of the material, these tunabilities of the magnetodynamic properties can be taken advantage of when employing NiMnSb films in magnonic devices. [ABSTRACT FROM AUTHOR]

The high Curie temperature multiferroic compound CuO has a quasidegenerate magnetic ground state that makes it prone to manipulation by the so-called "order-by-disorder" mechanism. First principle computations supplemented with Monte Carlo simulations and experiments show that isovalent doping allows us to stabilize the multiferroic phase in nonferroelectric regions of the pristine material phase diagram with experiments reaching a 250% widening of the ferroelectric temperature window with 5% of Zn doping. Our results allow us to validate the importance of a quasidegenerate ground state on promoting multiferroicity on CuO at high temperatures and open a path to the material engineering of multiferroic materials. In addition we present a complete explanation of the CuO phase diagram and a computation on the incommensurability in excellent agreement with experiment without free parameters. [ABSTRACT FROM AUTHOR]

In this work we examine critically the electronic structure of the rare-earth elements by use of the so-called Hubbard I approximation. From the theoretical side all measured features of both occupied and unoccupied states are reproduced, without significant deviations between observations and theory. We also examine cohesive properties like the equilibrium volume and bulk modulus, where we find, in general, a good agreement between theory and measurements. In addition, we have reproduced the spin and orbital moments of these elements as they are reflected from measurements of the saturation moment. We have also employed the Hubbard I approximation to extract the interatomic exchange parameters of an effective spin Hamiltonian for the heavy rare earths. We show that the Hubbard I approximation gives results which are consistent with calculations where 4f electrons are treated as core states for Gd. The latter approach was also used to address the series of the heavy/late rare earths. Via Monte Carlo simulations we obtained ordering temperatures which reproduce measurements within about 20%. We have further illustrated the accuracy of these exchange parameters by comparing measured and calculated magnetic configurations for the heavy rare earths and the magnon dispersion for Gd. The Hubbard I approximation is compared to other theories of the electronic structure, and we argue that it is superior. We discuss the relevance of our results in general and how this makes it possible to treat the electronic structure of materials containing rare-earth elements, such as permanent magnets, magnetostrictive compounds, photovoltaics, optical fibers, topological insulators, and molecular magnets. [ABSTRACT FROM AUTHOR]