Materials that crystallize in diamond-related lattices, with Si and GaAs as their prime examples, are at the foundation of modern electronics. Simultaneously, inversion asymmetries in their crystal ...structure and relativistic spinorbit coupling led to discoveries of non-equilibrium spin-polarization phenomena that are now extensively explored as an electrical means for manipulating magnetic moments in a variety of spintronic structures. Current research of these relativistic spinorbit torques focuses primarily on magnetic transition-metal multilayers. The low-temperature diluted magnetic semiconductor (Ga,Mn)As, in which spinorbit torques were initially discovered, has so far remained the only example showing the phenomenon among bulk non-centrosymmetric ferromagnets. Here we present a general framework, based on the complete set of crystallographic point groups, for identifying the potential presence and symmetry of spinorbit torques in non-centrosymmetric crystals. Among the candidate room-temperature ferromagnets we chose to use NiMnSb, which is a member of the broad family of magnetic Heusler compounds. By performing all-electrical ferromagnetic resonance measurements in single-crystal epilayers of NiMnSb we detect room-temperature spinorbit torques generated by eective elds of the expected symmetry and of a magnitude consistent with our ab initio calculations.
We carry out density functional theory calculations which demonstrate that the electron dynamics in the Skyrmion phase of Fe-rich Mn1-xFexGe alloys is governed by Berry phase physics. We observe that ...the magnitude of the Dzyaloshinskii-Moriya interaction directly related to the mixed space-momentum Berry phases, changes sign and magnitude with concentration x in direct correlation with the data of Shibata et al. Nat. Nanotechnol. 8, 723 (2013). The computed anomalous and topological Hall effects in FeGe are also in good agreement with available experiments. We further develop a simple tight-binding model able to explain these findings. Finally, we show that the adiabatic Berry phase picture is violated in the Mn-rich limit of the alloys.
The twofold coordinated heavier group-VI elements tellurium and selenium with the trigonal crystal structure have unshared electron pairs (lone pairs) which control the interplay of the intra- and ...inter-chain interactions and their sensitivity on pressure and temperature. We have developed tight-binding (TB) parameters for the helical structures of tellurium and selenium using the Naval Research Laboratory Tight-Binding (NRL-TB) method. The TB parameters were derived by fitting to the band structures and total energies of density functional theory (DFT) calculations. We have applied the TB parameters to study the phase stabilities of different structures under hydrostatic pressure. We have predicted (without fitting) the volume dependence of the rhombohedral and diamond structures, the bcc to rhombohedral and rhombohedral to simple cubic phase transitions and the elastic constants of the trigonal structures, all in agreement with ab initio and experimental results. While the results for the unrelaxed vacancy formation energies and surface energies are in good agreement with the DFT values, we find large discrepancies for the relaxed values indicating that the present set of TB parameters cannot accurately capture the inter-chain interactions.
Background
Effective hypertension self-management interventions are needed for socially disadvantaged African Americans, who have poorer blood pressure (BP) control compared to others.
Objective
We ...studied the incremental effectiveness of contextually adapted hypertension self-management interventions among socially disadvantaged African Americans.
Design
Randomized comparative effectiveness trial.
Participants
One hundred fifty-nine African Americans at an urban primary care clinic.
Interventions
Participants were randomly assigned to receive (1) a community health worker (“CHW”) intervention, including the provision of a home BP monitor; (2) the CHW plus additional training in shared decision-making skills (“DoMyPART”); or (3) the CHW plus additional training in self-management problem-solving (“Problem Solving”).
Main Measures
We assessed group differences in BP control (systolic BP (SBP) < 140 mm Hg and diastolic BP (DBP) < 90 mmHg), over 12 months using generalized linear mixed models. We also assessed changes in SBP and DBP and participants’ BP self-monitoring frequency, clinic visit patient-centeredness (i.e., extent of patient-physician discussions focused on patient emotional and psychosocial concerns), hypertension self-management behaviors, and self-efficacy.
Key Results
BP control improved in all groups from baseline (36%) to 12 months (52%) with significant declines in SBP (estimated mean 95% CI − 9.1 − 15.1, − 3.1, − 7.4 − 13.4, − 1.4, and − 11.3 − 17.2, − 5.3 mmHg) and DBP (− 4.8 − 8.3, − 1.3, − 4.0 − 7.5, − 0.5, and − 5.4 − 8.8, − 1.9 mmHg) for CHW, DoMyPART, and Problem Solving, respectively). There were no group differences in BP outcomes, BP self-monitor use, or clinic visit patient-centeredness. The Problem Solving group had higher odds of high hypertension self-care behaviors (OR 95% CI 18.7 4.0, 87.3) and self-efficacy scores (OR 95% CI 4.7 1.5, 14.9) at 12 months compared to baseline, while other groups did not. Compared to DoMyPART, the Problem Solving group had higher odds of high hypertension self-care behaviors (OR 95% CI 5.7 1.3, 25.5) at 12 months.
Conclusion
A context-adapted CHW intervention was correlated with improvements in BP control among socially disadvantaged African Americans. However, it is not clear whether improvements were the result of this intervention. Neither the addition of shared decision-making nor problem-solving self-management training to the CHW intervention further improved BP control.
Trial Registry
ClinicalTrials.gov
Identifier: NCT01902719
To create a set of criteria to assess facilitators and barriers to implementation among gender transformative interventions that target very young adolescents (VYAs) across different cultural ...settings.
Interventionists and researchers involved in the Global Early Adolescent Study created a Theory of Change (ToC) based on summarizing intervention components from five different gender transformative intervention curricula. Embedded within the ToC is a set of criteria labeled, ‘Conditions of Success’ which were developed to illustrate that change cannot happen unless interventions are implemented successfully. To test the feasibility of these criteria, implementation data collected across the five interventions in Global Early Adolescent Study were mapped onto the ‘Conditions for Success’ criteria and used to identify common facilitators and barriers to implementation.
Using the ‘Conditions for Success’ criteria, we found that gender transformative interventions targeting VYAs were most challenged in meeting program delivery and facilitation conditions and needed to build more multisectoral support to shift rigid gender norms. Parents and caregivers also needed to be engaged in the program either as a separate target population or as codesigners and implementers for the interventions.
The Conditions for Success criteria provide a useful framework for assessing facilitators and barriers to implementation among gender transformative interventions for VYAs. Additional research is underway to examine whether interventions that meet more conditions of success result in greater program impact, which will be used to further refine the overall ToC.
Inequitable gender norms are widespread and can be harmful to the wellbeing of adolescents. This study estimates the effects of two gender-transformative interventions, Semangat Dunia Remaja or Teen ...Aspirations (SETARA) and Growing Up Great! (GUG!), on gender norms perceptions and attitudes among very young adolescents in poor urban settings in Bandar Lampung, Semarang, Denpasar (Indonesia), and Kinshasa (Democratic Republic of the Congo).
The study draws from the longitudinal Global Early Adolescent Study, using a quasi-experimental design to evaluate the interventions. Data collection took place between 2017 and 2020. Our analytical samples included 2,159 adolescents in Kinshasa and 3,335 in Indonesia. We conducted a difference-in-difference analysis using generalized estimation equations and generalized linear models, after stratification by site and sex.
The interventions shifted a range of gender perceptions, although effects varied by program, city, and sex. SETARA shifted gender-normative perceptions related to traits, roles, and relations, while GUG! effects were more concentrated on attitudes toward chore sharing. SETARA was most effective in Semarang and Denpasar, but not in Bandar Lampung. In addition, both interventions were more consistently effective for girls than boys.
Gender-transformative interventions can effectively promote gender equality in early adolescence, but effects are program-specific and context-specific. Our findings emphasize the importance of defined theories of change and consistent implementation in gender-transformative intervention.
This article examines themes of academic resilience in the descriptions of academic achievement by three students at Benjamin High School, one of the least affluent high schools in Bayside, Florida. ...Through ethnographically informed interviews conducted during their senior year, coherent themes emerge that provide insight into these students' resilience. I argue that the students diminished the degree to which academic achievement separated them from their peers, in addition to situating achievement in a utilitarian fashion. Ultimately, acting on the notion of academic achievement in this manner positively impacted their resilience.
We demonstrate that biological molecules such as Watson-Crick DNA base pairs can behave as biological Aviram-Ratner electrical rectifiers because of the spatial separation and weak hydrogen bonding ...between the nucleobases. We have performed a parallel computational implementation of the ab initio non-equilibrium Green's function (NEGF) theory to determine the electrical response of graphene-base-pair-graphene junctions. The results show an asymmetric (rectifying) current-voltage response for the cytosine-guanine base pair adsorbed on a graphene nanogap. In sharp contrast we find a symmetric response for the thymine-adenine case. We propose applying the asymmetry of the current-voltage response as a sensing criterion to the technological challenge of rapid DNA sequencing via graphene nanogaps.
Ab initio
electronic structure calculations were carried out for bulk cadmium telluride (CdTe) and the unreconstructed CdTe polar (111) Cd-terminated and (
) Te-terminated surfaces. The hybrid ...functional for the exchange and correlation potential improves the overall description of the electronic structure of bulk CdTe, by lowering Cd 4d states and hence reducing the Cd 4d–Te 5p hybridization. The Cd–Te interlayer distance of the Cd-terminated surface exhibits a dramatic contraction in contrast with the expansion of the Te-terminated surface, and the surface relaxations decrease as the slab thickness increases. The underlying mechanism of the convergence of the electrostatic potential energy, work function, and electric dipole moment of the polar surfaces as a function of slab thickness is surface electron rearrangement leading to charge transfer from the Te- to the Cd-terminated surfaces. The surface electric polarization induces an internal electric field in the slab, which in turn tilts the bands of the slab double layers, thus rendering the surface layers metallic. The electric field decreases with increasing slab thickness due to convergence of the difference of electrostatic potentials between the Cd- and Te-terminated surfaces.
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