Abrupt Onset of Second Energy Gap at Superconducting Transition of Underdoped Bi2212

The superconducting gap - an energy scale tied to the superconducting phenomena-opens on the Fermi surface at the superconducting transition temperature (TC) in conventional BCS superconductors. Quite differently, in underdoped high-TC superconducting cuprates, a pseudogap, whose relation to the superconducting gap remains a mystery, develops well above TC. Whether the pseudogap is a distinct phenomenon or the incoherent continuation of the superconducting gap above TC is one of the central questions in high-TC research. While some experimental evidence suggests they are distinct, this issue is still under intense debate. A crucial piece of evidence to firmly establish this two-gap picture is still missing: a direct and unambiguous observation of a single-particle gap tied to the superconducting transition as function of temperature. Here we report the discovery of such an energy gap in underdoped Bi2212 in the momentum space region overlooked in previous measurements. Near the diagonal of Cu-O bond direction (nodal direction), we found a gap which opens at TC and exhibits a canonical (BCS-like) temperature dependence accompanied by the appearance of the so-called Bogoliubov quasiparticles, a classical signature of superconductivity. This is in sharp contrast to the pseudogap near the Cu-O bond direction (antinodal region) measured in earlier experiments. The emerging two-gap phenomenon points to a picture of richer quantum configurations in high temperature superconductors.Comment: 16 pages, 4 figures, authors' version Corrected typos in the abstrac

PENERAPAN PROJECT BASED LEARNING MODEL MELALUI KARYA SENI PERTUNJUKAN PADA KELOMPOK PETUALANG BELAJAR SEMI PALAR BANDUNG

Individu dalam proses pembelajarannya memiliki cara yang berbeda untuk mengembangkan berbagai kecerdasan yang ada dalam dirinya. Pada dasarnya, setiap peserta didik memiliki potensi dan minat untuk dikembangkan dalam menempuh pendidikannya sesuai kompetensi yang dimiliki. Tujuan penulisan ini adalah untuk mendeskripsikan bagaimana cara belajar Kelompok Petualang Belajar, membuat rancangan desain project based learning model melalui karya seni pertunjukan, mengimplementasikan rancangan, serta melakukan evaluasi terhadap keseluruhan proses dan hasil kegiatan seni berupa kreasi dan apresiasi. Penelitian ini dapat menjadi sebuah topik untuk diangkat dalam penelitian ilmiah. Dimana, peranan guru bukan semata-mata mengimplementasikan kurikulum saja melainkan mampu menafsirkan kata-kata dalam kurikulum yang bersifat normatif. Dengan kata lain, peranan guru disini harus menjadi pelaku yang kreatif dan interpretatif. Adapun penerapan model pembelajaran pada kelompok petualang belajar menjadi salah satu alternatif penerapan model yang tepat guna menghadapi generasi Z saat ini. Teori-teori yang digunakan dalam penelitian ini diantaranya: (1) teori belajar, (2) teori pendidikan, (3) teori generasi, (4) teori pembelajaran holistik, dan (5) karya seni pertunjukan. Penelitian ini menggunakan metode penelitian Project Based Research berdasarkan paradigma kualitatif dengan pendekatan multidisiplin. Adapun rancangan penelitian yang dilakukan ditempuh melalui diagnosis masalah, prescribe, implementasi, dan evaluasi. Project Based Learning Model Merupakan pembelajaran berbasis pada proyek dan pengalaman dengan mengembangkan minat dan potensi peserta didik. Hal ini ditujukan dengan adanya konsep pembelajaran seni terpadu yang diterapkan melalui karya seni pertunjukan.-----Individuals in the learning process have different ways to develop the various intelligences that exist in him. Basically, each learner has the potential and interest to be developed in his education according to the competence. The purpose of this paper is to describe how to learn Learning Group of Learners, to design the design of project based learning model through the works of performing arts, to implement the design, and to evaluate the whole process and the result of art activities in the form of creation and appreciation. This research can be a topic to be raised in scientific research. Where, the role of teachers is not merely to implement the curriculum alone but able to interpret the words in the curriculum that is normative. In other words, the role of the teacher here must be a creative and interpretive actor. The application of learning models in the group of learning adventurers to be an alternative application of appropriate models to face the current Z generation. Theories used in this research include: (1) learning theory, (2) educational theory, (3) generation theory, (4) holistic learning theory, and (5) works of performing arts. This research uses Research Based Research method based on qualitative paradigm with multidisciplinary approach. The research design is done through the diagnosis of problems, prescribe, implementation, and evaluation. Project Based Learning Model Merupakan pembelajaran berbasis pada proyek dan pengalaman dengan mengembangkan minat dan potensi peserta didik. Hal ini ditujukan dengan adanya konsep pembelajaran seni terpadu yang diterapkan melalui karya seni pertunjuka

Emotion regulation skills-focused interventions for chronic pain: A systematic review and meta-analysis

Objectives: To investigate the effect of emotion regulation skills-focused (ERSF) interventions to reduce pain intensity and improve psychological outcomes for people with chronic pain and to narratively report on safety and intervention compliance. Methods: Six databases and four registries were searched for randomized controlled trials (RCTs) up to 29 April 2022. Risk of bias was evaluated using the Cochrane RoB 2.0 tool, and certainty of evidence was assessed according to the Grading, Assessment, Development and Evaluation (GRADE). Meta-analyses for eight studies (902 participants) assessed pain intensity (primary outcome), emotion regulation, affect, symptoms of depression and anxiety, and pain interference (secondary outcomes), at two time points when available, post-intervention (closest to intervention end) and follow-up (the first measurement after the post-intervention assessment). Results: Compared to TAU, pain intensity improved post-intervention (weighted mean difference [WMD] = −10.86; 95% confidence interval [CI] [−17.55, −2.56]) and at follow-up (WMD = −11.38; 95% CI [−13.55, −9.21]). Emotion regulation improved post-intervention (standard mean difference [SMD] = 0.57; 95% CI [0.14, 1.01]), and depressive symptoms improved at follow-up (SMD = −0.45; 95% CI [−0.66, −0.24]). Compared to active comparators, anxiety symptoms improved favouring the comparator post-intervention (SMD = 0.10; 95% CI [0.03, 0.18]), and compared to CBT, pain interference improved post-intervention (SMD = −0.37; 95% CI [−0.69, −0.04]). Certainty of evidence ranged from very low to moderate. Significance: The findings provide evidence that ERSF interventions reduce pain intensity for people with chronic pain compared to usual treatment. These interventions are at least as beneficial to reduce pain intensity as the current gold standard psychological intervention, CBT. However, the limited number of studies and certainty of evidence mean further high-quality RCTs are warranted. Additionally, further research is needed to identify whether ERSF interventions may be more beneficial for specific chronic pain conditions

From Fermi Arcs to the Nodal Metal: Scaling of the Pseudogap with Doping and Temperature

The pseudogap phase in the cuprates is a most unusual state of matter: it is a metal, but its Fermi surface is broken up into disconnected segments known as Fermi arcs. Using angle resolved photoemission spectroscopy, we show that the anisotropy of the pseudogap in momentum space and the resulting arcs depend only on the ratio T/T*(x), where T*(x) is the temperature below which the pseudogap first develops at a given hole doping x. In particular, the arcs collapse linearly with T/T* and extrapolate to zero extent as T goes to 0. This suggests that the T = 0 pseudogap state is a nodal liquid, a strange metallic state whose gapless excitations are located only at points in momentum space, just as in a d-wave superconductor.Comment: to appear, Nature Physics (July 2006

The pseudogap: friend or foe of high Tc?

Although nineteen years have passed since the discovery of high temperature superconductivity, there is still no consensus on its physical origin. This is in large part because of a lack of understanding of the state of matter out of which the superconductivity arises. In optimally and underdoped materials, this state exhibits a pseudogap at temperatures large compared to the superconducting transition temperature. Although discovered only three years after the pioneering work of Bednorz and Muller, the physical origin of this pseudogap behavior and whether it constitutes a distinct phase of matter is still shrouded in mystery. In the summer of 2004, a band of physicists gathered for five weeks at the Aspen Center for Physics to discuss the pseudogap. In this perspective, we would like to summarize some of the results presented there and discuss its importance in the context of strongly correlated electron systems.Comment: expanded version, 20 pages, 11 figures, to be published, Advances in Physic

Disentangling Cooper-pair formation above Tc from the pseudogap state in the cuprates

The discovery of the pseudogap in the cuprates created significant excitement amongst physicists as it was believed to be a signature of pairing, in some cases well above the room temperature. In this "pre-formed pairs" scenario, the formation of pairs without quantum phase rigidity occurs below T*. These pairs condense and develop phase coherence only below Tc. In contrast, several recent experiments reported that the pseudogap and superconducting states are characterized by two different energy scales, pointing to a scenario, where the two compete. However a number of transport, magnetic, thermodynamic and tunneling spectroscopy experiments consistently detect a signature of phase-fluctuating superconductivity above leaving open the question of whether the pseudogap is caused by pair formation or not. Here we report the discovery of a spectroscopic signature of pair formation and demonstrate that in a region of the phase diagram commonly referred to as the "pseudogap", two distinct states coexist: one that persists to an intermediate temperature Tpair and a second that extends up to T*. The first state is characterized by a doping independent scaling behavior and is due to pairing above Tc, but significantly below T*. The second state is the "proper" pseudogap - characterized by a "checker board" pattern in STM images, the absence of pair formation, and is likely linked to Mott physics of pristine CuO2 planes. Tpair has a universal value around 130-150K even for materials with very different Tc, likely setting limit on highest, attainable Tc in cuprates. The observed universal scaling behavior with respect to Tpair indicates a breakdown of the classical picture of phase fluctuations in the cuprates.Comment: 9 pages, 4 figure

Direct evidence for a competition between the pseudogap and high temperature superconductivity in the cuprates

A pairing gap and coherence are the two hallmarks of superconductivity. In a classical BCS superconductor they are established simultaneously at Tc. In the cuprates, however, an energy gap (pseudogap) extends above Tc. The origin of this gap is one of the central issues in high temperature superconductivity. Recent experimental evidence demonstrates that the pseudogap and the superconducting gap are associated with different energy scales. It is however not clear whether they coexist independently or compete. In order to understand the physics of cuprates and improve their superconducting properties it is vital to determine whether the pseudogap is friend or foe of high temperature supercondctivity. Here we report evidence from angle resolved photoemission spectroscopy (ARPES) that the pseudogap and high temperature superconductivity represent two competing orders. We find that there is a direct correlation between a loss in the low energy spectral weight due to the pseudogap and a decrease of the coherent fraction of paired electrons. Therefore, the pseudogap competes with the superconductivity by depleting the spectral weight available for pairing in the region of momentum space where the superconducting gap is largest. This leads to a very unusual state in the underdoped cuprates, where only part of the Fermi surface develops coherence.Comment: Improved version was published in Natur

Estimating the burden of disease attributable to four selected environmental risk factors in South Africa

The first South African National Burden of Disease study quantified the underlying causes of premature mortality and morbidity experienced in South Africa in the year 2000. This was followed by a Comparative Risk Assessment to estimate the contributions of 17 selected risk factors to burden of disease in South Africa. This paper describes the health impact of exposure to four selected environmental risk factors: unsafe water, sanitation and hygiene; indoor air pollution from household use of solid fuels; urban outdoor air pollution and lead exposure.The study followed World Health Organization comparative risk assessment methodology. Population-attributable fractions were calculated and applied to revised burden of disease estimates (deaths and disability adjusted life years, [DALYs]) from the South African Burden of Disease study to obtain the attributable burden for each selected risk factor. The burden attributable to the joint effect of the four environmental risk factors was also estimated taking into account competing risks and common pathways. Monte Carlo simulation-modeling techniques were used to quantify sampling, uncertainty.Almost 24 000 deaths were attributable to the joint effect of these four environmental risk factors, accounting for 4.6% (95% uncertainty interval 3.8-5.3%) of all deaths in South Africa in 2000. Overall the burden due to these environmental risks was equivalent to 3.7% (95% uncertainty interval 3.4-4.0%) of the total disease burden for South Africa, with unsafe water sanitation and hygiene the main contributor to joint burden. The joint attributable burden was especially high in children under 5 years of age, accounting for 10.8% of total deaths in this age group and 9.7% of burden of disease.This study highlights the public health impact of exposure to environmental risks and the significant burden of preventable disease attributable to exposure to these four major environmental risk factors in South Africa. Evidence-based policies and programs must be developed and implemented to address these risk factors at individual, household, and community levels

Web-based alcohol intervention:study of systematic attrition of heavy drinkers

Background: Web-based alcohol interventions are a promising way to reduce alcohol consumption because of their anonymity and the possibility of reaching a high numbers of individuals including heavy drinkers. However, Web-based interventions are often characterized by high rates of attrition. To date, very few studies have investigated whether individuals with higher alcohol consumption show higher attrition rates in Web-based alcohol interventions as compared with individuals with lower alcohol consumption. Objectives: The aim of this study was to examine the attrition rate and predictors of attrition in a Web-based intervention study on alcohol consumption. Methods: The analysis of the predictors of attrition rate was performed on data collected in a Web-based randomized control trial. Data collection took place at the University of Konstanz, Germany. A total of 898 people, which consisted of 46.8% males (420/898) and 53.2% females (478/898) with a mean age of 23.57 years (SD 5.19), initially volunteered to participate in a Web-based intervention study to reduce alcohol consumption. Out of the sample, 86.9% (781/898) were students. Participants were classified as non-completers (439/898, 48.9%) if they did not complete the Web-based intervention. Potential predictors of attrition were self-reported: alcohol consumption in the last seven days, per week, from Monday to Thursday, on weekends, excessive drinking behavior measured with the Alcohol Use Disorder Identification Test (AUDIT), and drinking motives measured by the Drinking Motive Questionnaire (DMQ-R SF). Results: Significant differences between completers and non-completers emerged regarding alcohol consumption in the last seven days (B=-.02, P=.05, 95% CI [0.97-1.00]), on weekends (B=-.05, P=.003, 95% CI [0.92-0.98]), the AUDIT (B=-.06, P=.007, 95% CI [0.90-0.98], and the status as a student (B=.72, P=.001, 95% CI [1.35-3.11]). Most importantly, non-completers had a significantly higher alcohol consumption compared with completers. Conclusions: Hazardous alcohol consumption appears to be a key factor of the dropout rate in a Web-based alcohol intervention study. Thus, it is important to develop strategies to keep participants who are at high risk in Web-based interventions

The Heart of the Matter. About Good Nursing and Telecare

Nurses and ethicists worry that the implementation of care at a distance or telecare will impoverish patient care by taking out ‘the heart’ of the clinical work. This means that telecare is feared to induce the neglect of patients, and to possibly hinder the development of a personal relation between nurse and patient. This study aims to analyse whether these worries are warranted by analysing Dutch care practices using telemonitoring in care for chronic patients in the Netherlands. How do clinical practices of nursing change when telecare devices are introduced and what this means for notions and norms of good nursing? The paper concludes that at this point the practices studied do not warrant the fear of negligence and compromised relations. Quite the contrary; in the practices studied, telecare lead to more frequent and more specialised contacts between nurses and patients. The paper concludes by reflecting on the ethical implications of these changes