Pressure effects on the structural and superconducting transitions in La₃Co₄Sn₁₃

La3Co4Sn13 is a superconducting material with transition temperature at Tc = 2.70 K, which presents a superlattice structural transition at T ∗ ≃ 150 K, a common feature for this class of compounds. However, for this material, it is not clear that at T ∗ the lattice distortions arise from a charge density wave (CDW) or from a distinct microscopic origin. Interestingly, it has been suggested in isostructural non-magnetic intermetallic compounds that T ∗ can be suppressed to zero temperature, by combining chemical and external pressure, and a quantum critical point is argued to be observed near these critical doping/pressure. Our study shows that application of pressure on single-crystalline La3Co4Sn13 enhances Tc and decreases T ∗ . We observe thermal hysteresis loops for cooling/heating cycles around T ∗ for P & 0.6 GPa, in electrical resistivity measurements, which are not seen in x-ray diffraction data. The hysteresis in electrical measurements may be due to the pinning of the CDW phase to impurities/defects, while the superlattice structural transition maintains its ambient pressure second-order transition nature under pressure. From our experiments we estimate that T ∗ vanishes at around 5.5 GPa, though no quantum critical behavior is observed up to 2.53 GPa

How the 'plates' of a health system can shift, change and adjust during economic recessions: A qualitative interview study of public and private health providers in Brazil's Sao Paulo and Maranhao states

Background: Economic recessions carry an impact on population health and access to care; less is known on how health systems adapt to the conditions brought by a downturn. This particularly matters now that the COVID-19 epidemic is putting health systems under stress. Brazil is one of the world’s most affected countries, and its health system was already experiencing the aftermath of the 2015 recession. Methods: Between 2018 and 2019 we conducted 46 semi-structured interviews with health practitioners, managers and policy-makers to explore the impact of the 2015 recession on public and private providers in prosperous (São Paulo) and impoverished (Maranhão) states in Brazil. Thematic analysis was employed to identify drivers and consequences of system adaptation and coping strategies. Nvivo software was used to aid data collection and analysis. We followed the Standards for Reporting Qualitative Research to provide an account of the findings. Results: We found the concept of ‘health sector crisis’ to be politically charged among healthcare providers in São Paulo and Maranhão. Contrary to expectations, the public sector was reported to have found ways to compensate for diminishing federal funding, having outsourced services and adopted flexible–if insecure–working arrangements. Following a drop in employment and health plans, private health insurance companies have streamlined their offer, at times at the expenses of coverage. Low-cost walk-in clinics were hit hard by the recession, but were also credited for having moved to cater for higher-income customers in Maranhão. Conclusions: The ‘plates’ of a health system may shift and adjust in unexpected ways in response to recessions, and some of these changes might outlast the crisis. As low-income countries enter post-COVID economic recessions, it will be important to monitor the adjustments taking place in health systems, to ensure that past gains in access to care and job security are not eroded

Quantitative nanoscale vortex-imaging using a cryogenic quantum magnetometer

Microscopic studies of superconductors and their vortices play a pivotal role in our understanding of the mechanisms underlying superconductivity. Local measurements of penetration depths or magnetic stray-fields enable access to fundamental aspects of superconductors such as nanoscale variations of superfluid densities or the symmetry of their order parameter. However, experimental tools, which offer quantitative, nanoscale magnetometry and operate over the large range of temperature and magnetic fields relevant to address many outstanding questions in superconductivity, are still missing. Here, we demonstrate quantitative, nanoscale magnetic imaging of Pearl vortices in the cuprate superconductor YBCO, using a scanning quantum sensor in form of a single Nitrogen-Vacancy (NV) electronic spin in diamond. The sensor-to-sample distance of ~10nm we achieve allows us to observe striking deviations from the prevalent monopole approximation in our vortex stray-field images, while we find excellent quantitative agreement with Pearl's analytic model. Our experiments yield a non-invasive and unambiguous determination of the system's local London penetration depth, and are readily extended to higher temperatures and magnetic fields. These results demonstrate the potential of quantitative quantum sensors in benchmarking microscopic models of complex electronic systems and open the door for further exploration of strongly correlated electron physics using scanning NV magnetometry.Comment: Main text (5 pages, 4 figures) plus supplementary material (5 pages, 6 figures). Comments welcome. Further information under http://www.quantum-sensing.c

Determinants of the organization of diabetes mellitus care in user satisfaction

The objective of the study was analyze user satisfaction determinants of patients with Diabetes Mellitus (DM) regarding the outpatient clinic specialties at the Health Centre of the School. Qualitative cross-sectional study was carried out in outpatient specialty with 20 users with diagnosis of DM. We adopted the method of semi-structured interview using a scripting guide. We used Atlas it software 7.0 to aid in the decoding of speech, and analyzed it by content analysis. The empirical material encoded enabled to observe that the most evident themes are related to organizational accessibility and the relationship between user and service staff in perspective of longitudinality. It was observed the outpatient identifying clinic specialties as a regular source of care and dissatisfaction with regard to service accessibility.O objetivo do estudo foi analisar os determinantes da satisfação do usuário com Diabetes Mellitus (DM) sobre o atendimento no ambulatório de especialidades de um Centro de Saúde Escola. O estudo transversal com abordagem qualitativa foi desenvolvido no ambulatório de especialidades com 20 usuários com diagnóstico de DM. Foram aplicadas entrevistas semiestruturadas por meio de um roteiro norteador. Utilizou-se software Atlas ti 7.0 para auxílio na codificação das falas e técnica de Análise de Conteúdo para análise dos dados. Como resultado, observou-se que os temas mais evidenciados estão relacionados à acessibilidade organizacional e à relação entre usuário, equipe e serviço na perspectiva da longitudinalidade. Observou-se a identificação do ambulatório de especialidade como fonte regular de cuidado e a insatisfação no que se refere à acessibilidade ao serviço.