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2.
Science ; 371(6530): 716-721, 2021 02 12.
Artigo em Inglês | MEDLINE | ID: mdl-33479119

RESUMO

The distinctive electronic structure found at interfaces between materials can allow unconventional quantum states to emerge. Here we report on the discovery of superconductivity in electron gases formed at interfaces between (111)-oriented KTaO3 and insulating overlayers of either EuO or LaAlO3 The superconducting transition temperature, as high as 2.2 kelvin, is about one order of magnitude higher than that of the LaAlO3/SrTiO3 system. Notably, similar electron gases at KTaO3 (001) interfaces remain normal down to 25 millikelvin. The critical field and current-voltage measurements indicate that the superconductivity is two-dimensional. In EuO/KTaO3 (111) samples, a spontaneous in-plane transport anisotropy is observed before the onset of superconductivity, suggesting the emergence of a distinct "stripe"-like phase, which is also revealed near the critical field.

3.
Nat Commun ; 11(1): 1402, 2020 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-32179750

RESUMO

Amongst the rare-earth perovskite nickelates, LaNiO3 (LNO) is an exception. While the former have insulating and antiferromagnetic ground states, LNO remains metallic and non-magnetic down to the lowest temperatures. It is believed that LNO is a strange metal, on the verge of an antiferromagnetic instability. Our work suggests that LNO is a quantum critical metal, close to an antiferromagnetic quantum critical point (QCP). The QCP behavior in LNO is manifested in epitaxial thin films with unprecedented high purities. We find that the temperature and magnetic field dependences of the resistivity of LNO at low temperatures are consistent with scatterings of charge carriers from weak disorder and quantum fluctuations of an antiferromagnetic nature. Furthermore, we find that the introduction of a small concentration of magnetic impurities qualitatively changes the magnetotransport properties of LNO, resembling that found in some heavy-fermion Kondo lattice systems in the vicinity of an antiferromagnetic QCP.

4.
Small ; 15(14): e1900299, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30786158

RESUMO

Strongly correlated electronic molecules open the way for strong coupling between charge, spin, and lattice degrees of freedom to enable interdisciplinary fields, such as molecular electronic switches and plasmonics, spintronics, information storage, and superconducting circuits. However, despite exciting computational predictions and promising advantages to prepare flexible geometries, the electron correlation effect in molecules has been elusive. Here, the electron correlation effects of molecular plasmonic films are reported to uncover their coupling of charge, spin, lattice, and orbital for the switchable metal-to-insulator transition under external stimuli, at which the simultaneous transition occurs from the paramagnetic, electrical, and thermal conducting state to the diamagnetic, electrical, and thermal insulating state. In addition, density functional theory calculation and spectroscopic studies are combined to provide the mechanistic understanding of electronic transitions and molecular plasmon resonance observed in molecular conducting films. The self-assembled molecular correlated conductor paves the way for the next generation integrated micro/nanosystems.

5.
J Nurs Adm ; 48(11): 574-579, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-30335671

RESUMO

OBJECTIVE: The aim of this study was to develop better understanding of the leadership characteristics of clinical nurse leaders. BACKGROUND: Transformational leaders are the essential to support nursing in taking control of patient and family care coordination. One prior study of leadership and work engagement among clinical nurse leaders was identified. METHODS: This descriptive correlational study explored the relationship between transformational leadership practices and work engagement among nurse leaders in the United States. Sample consisted of clinical nursing leaders attending the 2016 Magnet® Conference. RESULTS: A significant positive relationship was identified between leadership practices and work engagement. Differences were noted in areas of select leadership practices and work engagement among nurse leaders based on different levels of education. Nurse leaders underperform in inspiring a shared vision, support for innovation, and taking risks, while also showing relatively weak levels of engagement in areas of vigor and absorption. CONCLUSION: There is a need for additional research to better understand the characteristics of clinical nurse leaders to promote the principles of transformational leadership.

6.
Ultramicroscopy ; 191: 56-65, 2018 08.
Artigo em Inglês | MEDLINE | ID: mdl-29843097

RESUMO

Combining multiple fast image acquisitions to mitigate scan noise and drift artifacts has proven essential for picometer precision, quantitative analysis of atomic resolution scanning transmission electron microscopy (STEM) data. For very low signal-to-noise ratio (SNR) image stacks - frequently required for undistorted imaging at liquid nitrogen temperatures - image registration is particularly delicate, and standard approaches may either fail, or produce subtly specious reconstructed lattice images. We present an approach which effectively registers and averages image stacks which are challenging due to their low-SNR and propensity for unit cell misalignments. Registering all possible image pairs in a multi-image stack leads to significant information surplus. In combination with a simple physical picture of stage drift, this enables identification of incorrect image registrations, and determination of the optimal image shifts from the complete set of relative shifts. We demonstrate the effectiveness of our approach on experimental, cryogenic STEM datasets, highlighting subtle artifacts endemic to low-SNR lattice images and how they can be avoided. High-SNR average images with information transfer out to 0.72 Å are achieved at 300 kV and with the sample cooled to near liquid nitrogen temperature.

7.
Nat Commun ; 9(1): 1799, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29728580

RESUMO

The coupling of ordered electronic phases with lattice, spin, and orbital degrees of freedom are of central interest in strongly correlated systems. Their interplay has been intensively studied from femtosecond to picosecond time scales, while their dynamics beyond nanoseconds are usually assumed to follow lattice cooling. Here, we report an unusual slowing down of the recovery of an electronic phase across a first-order phase transition. Following optical excitation, the recovery time of both transient optical reflectivity and X-ray diffraction intensity from the charge-ordered superstructure in a La1/3Sr2/3FeO3 thin film increases by orders of magnitude as the sample temperature approaches the phase transition temperature. In this regime, the recovery time becomes much longer than the lattice cooling time. The combined experimental and theoretical investigation shows that the slowing down of electronic recovery corresponds to the pseudo-critical dynamics that originates from magnetic interactions close to a weakly first-order phase transition.

8.
Sci Rep ; 7: 44805, 2017 03 20.
Artigo em Inglês | MEDLINE | ID: mdl-28317881

RESUMO

In order to understand the role of defects in chemical reactions, we used two types of samples, which are molecular beam epitaxy (MBE) grown NiO(001) film on Mg(001) substrate as the defect free NiO prototype and NiO grown on Ni(110) single crystal as the one with defects. In-situ observations for oxide-liquid interfacial structure and surface morphology were performed for both samples in water and Pb-contained solution using high-resolution X-ray reflectivity and atomic force microscopy. For the MBE grown NiO, no significant changes were detected in the high-resolution X-ray reflectivity data with monotonic increase in roughness. Meanwhile, in the case of native grown NiO on Ni(110), significant changes in both the morphology and atomistic structure at the interface were observed when immersed in water and Pb-contained solution. Our results provide simple and direct experimental evidence of the role of the defects in chemical reaction of oxide surfaces with both water and Pb-contained solution.

9.
J Emerg Nurs ; 43(2): 114-125, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27140230

RESUMO

ED volume and acuity were anticipated to increase at an inner-city hospital. A strategy to mitigate the impact was needed. METHODS: A multidisciplinary team facilitated a workflow modification project implementing a Super Track to treat low-acuity patients. A literature review led to the creation of an evidence-based framework. Staff education regarding the change process and the results of an analysis in the strengths, weaknesses, opportunities, and threat format, along with simulation exercises and a pilot project, supported implementation of this strategy. RESULTS: Simulation exercises demonstrated that the proposed workflow with a Super Track had the potential to reduce the length of stay among level 4 and 5 patients coming to the emergency department. Implementing a Super Track reduced the patient arrival-to-provider time for low-acuity patients, but length of stay was not affected. After implementation, the number of patients who left without being seen decreased by 40%, and patient satisfaction increased by 36%. IMPLICATIONS FOR PRACTICE: A modified front-end workflow process produced a statistically significant, sustainable improvement in patient flow of low-acuity patients in our emergency department. Use of an evidence-based, multidisciplinary team approach supported the change process.


Assuntos
Enfermagem em Emergência/métodos , Serviço Hospitalar de Emergência/organização & administração , Serviço Hospitalar de Emergência/estatística & dados numéricos , Hospitais Urbanos , Gravidade do Paciente , Fluxo de Trabalho , Eficiência Organizacional/estatística & dados numéricos , Humanos , Tempo de Internação/estatística & dados numéricos , Fatores de Tempo
10.
Nat Commun ; 7: 12974, 2016 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-27680386

RESUMO

When an electronic system is subjected to a sufficiently strong magnetic field that the cyclotron energy is much larger than the Fermi energy, the system enters the extreme quantum limit (EQL) and becomes susceptible to a number of instabilities. Bringing a three-dimensional electronic system deeply into the EQL can be difficult however, since it requires a small Fermi energy, large magnetic field, and low disorder. Here we present an experimental study of the EQL in lightly-doped single crystals of strontium titanate. Our experiments probe deeply into the regime where theory has long predicted an interaction-driven charge density wave or Wigner crystal state. A number of interesting features arise in the transport in this regime, including a striking re-entrant nonlinearity in the current-voltage characteristics. We discuss these features in the context of possible correlated electron states, and present an alternative picture based on magnetic-field induced puddling of electrons.

11.
Phys Rev Lett ; 116(9): 097204, 2016 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-26991198

RESUMO

We report on the observation of the spin Seebeck effect in antiferromagnetic MnF_{2}. A device scale on-chip heater is deposited on a bilayer of MnF_{2} (110) (30 nm)/Pt (4 nm) grown by molecular beam epitaxy on a MgF_{2} (110) substrate. Using Pt as a spin detector layer, it is possible to measure the thermally generated spin current from MnF_{2} through the inverse spin Hall effect. The low temperature (2-80 K) and high magnetic field (up to 140 kOe) regime is explored. A clear spin-flop transition corresponding to the sudden rotation of antiferromagnetic spins out of the easy axis is observed in the spin Seebeck signal when large magnetic fields (>9 T) are applied parallel to the easy axis of the MnF_{2} thin film. When the magnetic field is applied perpendicular to the easy axis, the spin-flop transition is absent, as expected.

12.
J Am Soc Hypertens ; 9(9): 725-34, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26369442

RESUMO

Hypertension is a lifelong condition; thus, long-term adherence to lifestyle modification, self-monitoring, and medication regimens remains a challenge for patients. The aim of this study was to develop a patient-reported hypertension instrument that measured attitudes, lifestyle behaviors, adherence, and barriers to hypertension management using patient-reported outcome data. The study was conducted using the Open Research Exchange software platform created by PatientsLikeMe. A total of 360 participants completed the psychometric phase of the study; incomplete responses were obtained from 147 patients, and 150 patients opted out. Principal component analysis with orthogonal (varimax) rotation was executed on a data set with all completed responses (N = 249) and applied to 43 items. Based on the review of the factor solution, eigenvalues, and item loadings, 16 items were eliminated and model with 29 items was tested. The process was repeated two more times until final model with 14 items was established. In interpreting the rotated factor pattern, an item was said to load on any given component if the factor loading was ≥0.40 for that component and was <0.40 for the other. In addition to the newly generated instrument, demographic and self-reported clinical characteristics of the study participants such as the type of prescribed hypertension medications, frequency of blood pressure monitoring, and comorbid conditions were examined. The Open Research Exchange platform allowed for ongoing input from patients through each stage of the 14-item instrument development.


Assuntos
Gerenciamento Clínico , Hipertensão/terapia , Cooperação do Paciente , Mídias Sociais , Inquéritos e Questionários , Monitorização Ambulatorial da Pressão Arterial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Participação do Paciente , Análise de Componente Principal , Reprodutibilidade dos Testes
13.
Phys Rev Lett ; 114(18): 186602, 2015 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-26001014

RESUMO

We report the observation of the longitudinal spin Seebeck effect in paramagnetic insulators. By using a microscale on-chip local heater, we generate a large thermal gradient confined to the chip surface without a large increase in the total sample temperature. Using this technique at low temperatures (<20 K), we resolve the paramagnetic spin Seebeck effect in the insulating paramagnets Gd3Ga5O12 (gadolinium gallium garnet) and DyScO3 (DSO), using either W or Pt as the spin detector layer. By taking advantage of the strong magnetocrystalline anisotropy of DSO, we eliminate contributions from the Nernst effect in W or Pt, which produces a phenomenologically similar signal.

14.
J Nurs Educ ; 54(3 Suppl): S39-46, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25693112

RESUMO

This cross-sectional study examined accelerated second-degree (n = 117) and traditional (n = 71) baccalaureate nursing (BSN) graduates from a large, private, urban university in the mid-Atlantic United States regarding demographics, professional outcomes, and career satisfaction using an electronic survey. Results showed a statistically significant difference in two professional development variables: plans to return for an advanced nursing degree and membership in nursing professional organizations. There was no statistically significant difference in career satisfaction between accelerated second-degree and traditional BSN graduates. These findings indicated that both accelerated second-degree and traditional BSN graduates, despite matriculation in different nursing curricular models, have similar professional outcomes and career satisfaction.


Assuntos
Escolha da Profissão , Bacharelado em Enfermagem/organização & administração , Satisfação no Emprego , Adulto , Competência Clínica , Estudos Transversais , Demografia , Feminino , Humanos , Masculino , Pesquisa em Educação de Enfermagem , Fatores Socioeconômicos , Adulto Jovem
15.
Nat Commun ; 5: 4283, 2014 Jul 09.
Artigo em Inglês | MEDLINE | ID: mdl-25005724

RESUMO

Lattice distortion due to oxygen octahedral rotations have a significant role in mediating the magnetism in oxides, and recently attracts a lot of interests in the study of complex oxides interface. However, the direct experimental evidence for the interrelation between octahedral rotation and magnetism at interface is scarce. Here we demonstrate that interfacial octahedral rotation are closely linked to the strongly modified ferromagnetism in (LaMnO3+δ)N/(SrTiO3)N superlattices. The maximized ferromagnetic moment in the N=6 superlattice is accompanied by a metastable structure (space group Imcm) featuring minimal octahedral rotations (a(-)a(-)c(-), α~4.2°, γ~0.5°). Quenched ferromagnetism for N<4 superlattices is correlated to a substantially enhanced c axis octahedral rotation (a(-)a(-)c(-), α~3.8°, γ~8° for N=2). Monte-Carlo simulation based on double-exchange model qualitatively reproduces the experimental observation, confirming the correlation between octahedral rotation and magnetism. Our study demonstrates that engineering superlattices with controllable interfacial structures can be a feasible new route in realizing functional magnetic materials.

16.
Nano Lett ; 14(5): 2694-701, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24734897

RESUMO

Complex oxides displaying ferroelectric and/or multiferroic behavior are of high fundamental and applied interest. In this work, we show that it is possible to achieve polar order in a superlattice made up of two nonpolar oxides by means of oxygen vacancy ordering. Using scanning transmission electron microscopy imaging, we show the polar displacement of magnetic Fe ions in a superlattice of (LaFeO3)2/(SrFeO3) grown on a SrTiO3 substrate. Using density functional theory calculations, we systematically study the effect of epitaxial strain, octahedral rotations, and surface terminations in the superlattice and find them to have a negligible effect on the antipolar displacements of the Fe ions lying in between SrO and LaO layers of the superlattice (i.e., within La0.5Sr0.5FeO3 unit cells). The introduction of oxygen vacancies, on the other hand, triggers a polar displacement of the Fe ions. We confirm this important result using electron energy loss spectroscopy, which shows partial oxygen vacancy ordering in the region where polar displacements are observed and an absence of vacancy ordering outside of that area.

17.
Nurs Outlook ; 61(6): 437-46, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23910927

RESUMO

BACKGROUND: Excellence underscores the need for nurses to keep their skills and competencies current through participation in professional development and career advancement. Evidence suggests that internationally educated nurses (IENs) progress relatively slowly through the career ladder and participate less in professional development compared with nurses educated in the United States (UENs). Mentorship and self-efficacy are considered major determinants of career advancement. PURPOSE: The aim of the study was to understand the differences in levels of mentorship function and self-efficacy as well as the differences in participation in professional development and career advancement between UENs and IENs. METHOD: A descriptive survey design was implemented using a Web-based survey. RESULTS: Significant disparities were noted in the role model function of mentoring and some professional development and career advancement measures between UENs and IENs. Mentorship is essential for professional growth. Sociodemographic characteristics of mentors are important because mentors are role models. CONCLUSION: Standardized career advancement structures are needed to promote professional growth.


Assuntos
Mobilidade Ocupacional , Educação em Enfermagem/estatística & dados numéricos , Pessoal Profissional Estrangeiro/psicologia , Mentores/estatística & dados numéricos , Recursos Humanos de Enfermagem no Hospital/psicologia , Autoeficácia , Desenvolvimento de Pessoal/estatística & dados numéricos , Adulto , Idoso , Estudos Transversais , Feminino , Pessoal Profissional Estrangeiro/estatística & dados numéricos , Humanos , Masculino , Pessoa de Meia-Idade , Recursos Humanos de Enfermagem no Hospital/estatística & dados numéricos , Estados Unidos , Adulto Jovem
18.
Sci Rep ; 3: 1876, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23703150

RESUMO

A central goal of electronics based on correlated materials or 'Mottronics' is the ability to switch between distinct collective states with a control voltage. Small changes in structure and charge density near a transition can tip the balance between competing phases, leading to dramatic changes in electronic and magnetic properties. In this work, we demonstrate that an electric field induced two-step ferroelastic switching pathway in (011) oriented 0.71Pb(Mg1/3Nb2/3)O3-0.29PbTiO3 (PMN-PT) substrates can be used to tune the Verwey metal-insulator transition in epitaxial Fe3O4 films in a stable and reversible manner. We also observe robust non-volatile resistance switching in Fe3O4 up to room temperature, driven by ferroelastic strain. These results provides a framework for realizing non-volatile and reversible tuning of order parameters coupled to lattice-strain in epitaxial oxide heterostructures over a broad range of temperatures, with potential device applications.

19.
J Adv Nurs ; 69(11): 2470-80, 2013 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-23488910

RESUMO

AIM: To increase understanding of women's decision-making process concerning the medication use for anxiety and/or depression while pregnant. BACKGROUND: Anxiety and depression affects many pregnant women, yet the decision to take psychotropic medication is complex and possibly subject to social oppression. DESIGN: Cross-sectional descriptive survey design. METHODS: A web-based survey was used to collect data from a convenience sample of 143 pregnant women over 3 months beginning in early 2011. An independent t-test was conducted to determine differences in satisfaction between women with high and low levels of emancipated decision-making (EDM). A multiple regression analysis was conducted to determine which subscales of the emancipation scale best predict level of satisfaction with the decision. FINDINGS: The majority of respondents were White, between 25-34 years of age. The group with lower levels of emancipation reported lower mean satisfaction scores compared with those with higher levels of emancipation. Regression analysis showed that the three subscale emancipation model was a statistically significant predictor of satisfaction with the decision and accounted for 54% of the variance in satisfaction. The subconcept of personal knowledge was most predictive of satisfaction with decision. CONCLUSIONS: Women may be able to overcome oppressive forces by using an EDM process. EDM allows them to make a decision that feels right for them and to feel satisfied with the decision.


Assuntos
Transtornos de Ansiedade/tratamento farmacológico , Tomada de Decisões , Transtorno Depressivo/tratamento farmacológico , Complicações na Gravidez/psicologia , Psicotrópicos/administração & dosagem , Adolescente , Adulto , Estudos Transversais , Feminino , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Pessoa de Meia-Idade , Satisfação do Paciente , Gravidez , Inquéritos e Questionários , Adulto Jovem
20.
Nurs Clin North Am ; 47(4): 435-53, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23137597

RESUMO

This article reports on a national study of doctoral nursing faculty, including both PhD and Doctor of Nursing Practice (DNP) faculty. Using a national sample of 624 doctoral nursing faculty, we surveyed individuals on a variety of issues, including succession planning, retirement, quality of life as a doctoral faculty member, their views on the new DNP degree, and how they view the future of doctoral nursing education. Study implications for both DNP and PhD faculty are explored and the meaning of the findings of the study for the future are discussed, including new items that will be investigated in a repeat survey in 2012.


Assuntos
Atitude do Pessoal de Saúde , Educação de Pós-Graduação em Enfermagem/organização & administração , Docentes de Enfermagem , Educação de Pós-Graduação em Enfermagem/tendências , Humanos , Pesquisa em Educação de Enfermagem , Pesquisa Metodológica em Enfermagem , Estados Unidos
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