101 research outputs found
Characteristics of Quantum-Classical Correspondence for Two Interacting Spins
The conditions of quantum-classical correspondence for a system of two
interacting spins are investigated. Differences between quantum expectation
values and classical Liouville averages are examined for both regular and
chaotic dynamics well beyond the short-time regime of narrow states. We find
that quantum-classical differences initially grow exponentially with a
characteristic exponent consistently larger than the largest Lyapunov exponent.
We provide numerical evidence that the time of the break between the quantum
and classical predictions scales as log(), where is
a characteristic system action. However, this log break-time rule applies only
while the quantum-classical deviations are smaller than order hbar. We find
that the quantum observables remain well approximated by classical Liouville
averages over long times even for the chaotic motions of a few
degree-of-freedom system. To obtain this correspondence it is not necessary to
introduce the decoherence effects of a many degree-of-freedom environment.Comment: New introduction, accepted in Phys Rev A (May 2001 issue), 12 latex
figures, 3 ps figure
Dynamical Stability of an Ion in a Linear Trap as a Solid-State Problem of Electron Localization
When an ion confined in a linear ion trap interacts with a coherent laser
field, the internal degrees of freedom, related to the electron transitions,
couple to the vibrational degree of freedom of the ion. As a result of this
interaction, quantum dynamics of the vibrational degree of freedom becomes
complicated, and in some ranges of parameters even chaotic. We analyze the
vibrational ion dynamics using a formal analogy with the solid-state problem of
electron localization. In particular, we show how the resonant approximation
used in analysis of the ion dynamics, leads to a transition from a
two-dimensional (2D) to a one-dimensional problem (1D) of electron
localization. The localization length in the solid-state problem is estimated
in cases of weak and strong interaction between the cites of the 2D cell by
using the methods of resonance perturbation theory, common in analysis of 1D
time-dependent dynamical systems.Comment: 18 pages RevTe
Chaos and Quantum-Classical Correspondence via Phase Space Distribution Functions
Quantum-classical correspondence in conservative chaotic Hamiltonian systems
is examined using a uniform structure measure for quantal and classical phase
space distribution functions. The similarities and differences between quantum
and classical time-evolving distribution functions are exposed by both
analytical and numerical means. The quantum-classical correspondence of
low-order statistical moments is also studied. The results shed considerable
light on quantum-classical correspondence.Comment: 16 pages, 5 figures, to appear in Physical Review
Thermal conductivity via magnetic excitations in spin-chain materials
We discuss the recent progress and the current status of experimental
investigations of spin-mediated energy transport in spin-chain and spin-ladder
materials with antiferromagnetic coupling. We briefly outline the central
results of theoretical studies on the subject but focus mainly on recent
experimental results that were obtained on materials which may be regarded as
adequate physical realizations of the idealized theoretical model systems. Some
open questions and unsettled issues are also addressed.Comment: 17 pages, 4 figure
Methodologies for <i>in vitro</i> and <i>in vivo</i> evaluation of efficacy of antifungal and antibiofilm agents and surface coatings against fungal biofilms.
Unlike superficial fungal infections of the skin and nails, which are the most common fungal diseases in humans, invasive fungal infections carry high morbidity and mortality, particularly those associated with biofilm formation on indwelling medical devices. Therapeutic management of these complex diseases is often complicated by the rise in resistance to the commonly used antifungal agents. Therefore, the availability of accurate susceptibility testing methods for determining antifungal resistance, as well as discovery of novel antifungal and antibiofilm agents, are key priorities in medical mycology research. To direct advancements in this field, here we present an overview of the methods currently available for determining (i) the susceptibility or resistance of fungal isolates or biofilms to antifungal or antibiofilm compounds and compound combinations; (ii) the <i>in vivo</i> efficacy of antifungal and antibiofilm compounds and compound combinations; and (iii) the <i>in vitro</i> and <i>in vivo</i> performance of anti-infective coatings and materials to prevent fungal biofilm-based infections
Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study
A41 Use of SMS texts for facilitating access to online alcohol interventions: a feasibility study
In: Addiction Science & Clinical Practice 2017, 12(Suppl 1): A4
Paleobiology of titanosaurs: reproduction, development, histology, pneumaticity, locomotion and neuroanatomy from the South American fossil record
Fil: GarcĂa, Rodolfo A.. Instituto de InvestigaciĂłn en PaleobiologĂa y GeologĂa. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Salgado, Leonardo. Instituto de InvestigaciĂłn en PaleobiologĂa y GeologĂa. General Roca. RĂo Negro; ArgentinaFil: FernĂĄndez, Mariela. Inibioma-Centro Regional Universitario Bariloche. Bariloche. RĂo Negro; ArgentinaFil: Cerda, Ignacio A.. Instituto de InvestigaciĂłn en PaleobiologĂa y GeologĂa. Museo Provincial Carlos Ameghino. Cipolletti; ArgentinaFil: Carabajal, Ariana Paulina. Museo Carmen Funes. Plaza Huincul. NeuquĂ©n; ArgentinaFil: Otero, Alejandro. Museo de La Plata. Universidad Nacional de La Plata; ArgentinaFil: Coria, Rodolfo A.. Instituto de PaleobiologĂa y GeologĂa. Universidad Nacional de RĂo Negro. NeuquĂ©n; ArgentinaFil: Fiorelli, Lucas E.. Centro Regional de Investigaciones CientĂficas y Transferencia TecnolĂłgica. Anillaco. La Rioja; Argentin
Exercise may cause myocardial ischemia at the anaerobic threshold in cardiac rehabilitation programs
Tracking development assistance for health and for COVID-19 : a review of development assistance, government, out-of-pocket, and other private spending on health for 204 countries and territories, 1990-2050
Background The rapid spread of COVID-19 renewed the focus on how health systems across the globe are financed, especially during public health emergencies. Development assistance is an important source of health financing in many low-income countries, yet little is known about how much of this funding was disbursed for COVID-19. We aimed to put development assistance for health for COVID-19 in the context of broader trends in global health financing, and to estimate total health spending from 1995 to 2050 and development assistance for COVID-19 in 2020. Methods We estimated domestic health spending and development assistance for health to generate total health-sector spending estimates for 204 countries and territories. We leveraged data from the WHO Global Health Expenditure Database to produce estimates of domestic health spending. To generate estimates for development assistance for health, we relied on project-level disbursement data from the major international development agencies' online databases and annual financial statements and reports for information on income sources. To adjust our estimates for 2020 to include disbursements related to COVID-19, we extracted project data on commitments and disbursements from a broader set of databases (because not all of the data sources used to estimate the historical series extend to 2020), including the UN Office of Humanitarian Assistance Financial Tracking Service and the International Aid Transparency Initiative. We reported all the historic and future spending estimates in inflation-adjusted 2020 US per capita, purchasing-power parity-adjusted US8. 8 trillion (95% uncertainty interval [UI] 8.7-8.8) or 40.4 billion (0.5%, 95% UI 0.5-0.5) was development assistance for health provided to low-income and middle-income countries, which made up 24.6% (UI 24.0-25.1) of total spending in low-income countries. We estimate that 13.7 billion was targeted toward the COVID-19 health response. 1.4 billion was repurposed from existing health projects. 2.4 billion (17.9%) was for supply chain and logistics. Only 1519 (1448-1591) per person in 2050, although spending across countries is expected to remain varied. Interpretation Global health spending is expected to continue to grow, but remain unequally distributed between countries. We estimate that development organisations substantially increased the amount of development assistance for health provided in 2020. Continued efforts are needed to raise sufficient resources to mitigate the pandemic for the most vulnerable, and to help curtail the pandemic for all. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.Peer reviewe
Risk profiles and one-year outcomes of patients with newly diagnosed atrial fibrillation in India: Insights from the GARFIELD-AF Registry.
BACKGROUND: The Global Anticoagulant Registry in the FIELD-Atrial Fibrillation (GARFIELD-AF) is an ongoing prospective noninterventional registry, which is providing important information on the baseline characteristics, treatment patterns, and 1-year outcomes in patients with newly diagnosed non-valvular atrial fibrillation (NVAF). This report describes data from Indian patients recruited in this registry. METHODS AND RESULTS: A total of 52,014 patients with newly diagnosed AF were enrolled globally; of these, 1388 patients were recruited from 26 sites within India (2012-2016). In India, the mean age was 65.8 years at diagnosis of NVAF. Hypertension was the most prevalent risk factor for AF, present in 68.5% of patients from India and in 76.3% of patients globally (P < 0.001). Diabetes and coronary artery disease (CAD) were prevalent in 36.2% and 28.1% of patients as compared with global prevalence of 22.2% and 21.6%, respectively (P < 0.001 for both). Antiplatelet therapy was the most common antithrombotic treatment in India. With increasing stroke risk, however, patients were more likely to receive oral anticoagulant therapy [mainly vitamin K antagonist (VKA)], but average international normalized ratio (INR) was lower among Indian patients [median INR value 1.6 (interquartile range {IQR}: 1.3-2.3) versus 2.3 (IQR 1.8-2.8) (P < 0.001)]. Compared with other countries, patients from India had markedly higher rates of all-cause mortality [7.68 per 100 person-years (95% confidence interval 6.32-9.35) vs 4.34 (4.16-4.53), P < 0.0001], while rates of stroke/systemic embolism and major bleeding were lower after 1 year of follow-up. CONCLUSION: Compared to previously published registries from India, the GARFIELD-AF registry describes clinical profiles and outcomes in Indian patients with AF of a different etiology. The registry data show that compared to the rest of the world, Indian AF patients are younger in age and have more diabetes and CAD. Patients with a higher stroke risk are more likely to receive anticoagulation therapy with VKA but are underdosed compared with the global average in the GARFIELD-AF. CLINICAL TRIAL REGISTRATION-URL: http://www.clinicaltrials.gov. Unique identifier: NCT01090362
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