2,608 research outputs found
Growing interfaces uncover universal fluctuations behind scale invariance
Stochastic motion of a point -- known as Brownian motion -- has many
successful applications in science, thanks to its scale invariance and
consequent universal features such as Gaussian fluctuations. In contrast, the
stochastic motion of a line, though it is also scale-invariant and arises in
nature as various types of interface growth, is far less understood. The two
major missing ingredients are: an experiment that allows a quantitative
comparison with theory and an analytic solution of the Kardar-Parisi-Zhang
(KPZ) equation, a prototypical equation for describing growing interfaces. Here
we solve both problems, showing unprecedented universality beyond the scaling
laws. We investigate growing interfaces of liquid-crystal turbulence and find
not only universal scaling, but universal distributions of interface positions.
They obey the largest-eigenvalue distributions of random matrices and depend on
whether the interface is curved or flat, albeit universal in each case. Our
exact solution of the KPZ equation provides theoretical explanations.Comment: 5 pages, 3 figures, supplementary information available on Journal
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Life expectancy gains from dietary modifications: a comparative modeling study in 7 countries
\ua9 2024 The Author(s). Background: Eating healthier is associated with a range of favorable health outcomes. Our previous model estimated the impact of dietary changes on life expectancy gains but did not consider height, weight, or physical activity. Objectives: We aimed to estimate the increase in life expectancy resulting from the transition from typical national dietary patterns to longevity-optimizing dietary changes, more feasible dietary modifications, and optimized vegan dietary changes in China, France, Germany, Iran, Norway, the United Kingdom, and the United States. Methods: Our modeling study used data from meta-analyses presenting dose-response relationships between intake of 15 food groups and mortality. Background mortality data were from the Global Burden of Disease Study. We used national food intake data and adjusted for height, weight, and physical activity level. Results: For 40-y-olds, estimated life expectancy gains ranged from 6.2 y (with uncertainty interval [UI]: 5.7, 7.5 y) for Chinese females to 9.7 y (UI: 8.1, 11.3 y) for United States males following sustained changes from typical country-specific dietary patterns to longevity-optimized dietary changes, and from 5.2 y (UI: 4.0, 6.5 y) for Chinese females to 8.7 y (UI: 7.1, 10.3 y) for United States males following changes to optimized vegan dietary changes. Conclusions: A sustained change from country-specific typical dietary pattern patterns to longevity-optimized dietary changes, more feasible dietary changes, or optimized vegan dietary changes are all projected to result in substantial life expectancy gains across ages and countries. These changes included more whole grains, legumes, and nuts and less red/processed meats and sugars and sugar-sweetened beverages. The largest gains from dietary changes would be in the United States
Distributional cost-effectiveness analysis in low- and middle-income countries: illustrative example of rotavirus vaccination in Ethiopia
Reducing health inequality is a major policy concern for low- and middle-income countries (LMICs) on the path to universal health coverage. However, health inequality impacts are rarely quantified in cost-effectiveness analyses of health programmes. Distributional cost-effectiveness analysis (DCEA) is a method developed to analyse the expected social distributions of costs and health benefits, and the potential trade-offs that may exist between maximising total health and reducing health inequality. This is the first paper to show how DCEA can be applied in LMICs. Using the introduction of rotavirus vaccination in Ethiopia as an illustrative example, we analyse a hypothetical re-designed vaccination programme, which invests additional resources into vaccine delivery in rural areas, and compare this with the standard programme currently implemented in Ethiopia. We show that the re-designed programme has an incremental cost-effectiveness ratio of US$69 per health-adjusted life year (HALY) compared with the standard programme. This is potentially cost-ineffective when compared with current estimates of health opportunity cost in Ethiopia. However, rural populations are typically less wealthy than urban populations and experience poorer lifetime health. Prioritising such populations can thus be seen as being equitable. We analyse the trade-off between cost-effectiveness and equity using the Atkinson inequality aversion parameter, Δ , representing the decision makerâs strength of concern for reducing health inequality. We find that the more equitable programme would be considered worthwhile by a decision maker whose inequality concern is greater than Δ =â5.66, which at current levels of health inequality in Ethiopia implies that health gains are weighted at least 3.86 times more highly in the poorest compared with the richest wealth quintile group. We explore the sensitivity of this conclusion to a range of assumptions and cost-per-HALY threshold values, to illustrate how DCEA can inform the thinking of decision makers and stakeholders about health equity trade-offs
Costs and sustainable financing of integrated community case management of common child illnesses in Uganda and Mozambique
Anaphylactic response to topical fluorescein 2% eye drops: a case report
<p>Abstract</p> <p>Introduction</p> <p>The intravenous use of fluorescein 10% during retinal angiography can cause severe systemic reactions including, on rare occasions, anaphylaxis. Fluorescein 2% eye drops are used extensively for clinical examination and diagnosis, but to the best of our knowledge, they have only been reported as being responsible for a systemic anaphylactic response on two previous occasions.</p> <p>Case presentation</p> <p>We report the case of a 51-year-old woman who developed an anaphylactic reaction when she was administered fluorescein sodium 2% eye drops after cataract surgery. This was the second time she had been exposed to fluorescein. She had brittle asthma and a history of anaphylaxis following exposure to a variety of drug and food allergens. She was successfully resuscitated and recovered completely over a period of two days.</p> <p>Conclusions</p> <p>Fluorescein 2% drops are universally used in general practice, ophthalmology, optometry, and casualty departments. Our case report reveals the potential for this benign eye drop to cause a life-threatening systemic reaction and emphasises the importance of considering this consequence when administering topical fluorescein 2% to a patient with a history of anaphylaxis to other allergens.</p
Coherent quantum phase slip
A hundred years after discovery of superconductivity, one fundamental
prediction of the theory, the coherent quantum phase slip (CQPS), has not been
observed. CQPS is a phenomenon exactly dual to the Josephson effect: whilst the
latter is a coherent transfer of charges between superconducting contacts, the
former is a coherent transfer of vortices or fluxes across a superconducting
wire. In contrast to previously reported observations of incoherent phase slip,
the CQPS has been only a subject of theoretical study. Its experimental
demonstration is made difficult by quasiparticle dissipation due to gapless
excitations in nanowires or in vortex cores. This difficulty might be overcome
by using certain strongly disordered superconductors in the vicinity of the
superconductor-insulator transition (SIT). Here we report the first direct
observation of the CQPS in a strongly disordered indium-oxide (InOx)
superconducting wire inserted in a loop, which is manifested by the
superposition of the quantum states with different number of fluxes. Similarly
to the Josephson effect, our observation is expected to lead to novel
applications in superconducting electronics and quantum metrology.Comment: 14 pages, 3 figure
Aging Logarithmic Conformal Field Theory : a holographic view
We consider logarithmic extensions of the correlation and response functions
of scalar operators for the systems with aging as well as Schr\"odinger
symmetry. Aging is known to be the simplest nonequilibrium phenomena, and its
physical significances can be understood by the two-time correlation and
response functions. Their logarithmic part is completely fixed by the bulk
geometry in terms of the conformal weight of the dual operator and the dual
particle number.
Motivated by recent experimental realizations of Kardar-Parisi-Zhang
universality class in growth phenomena and its subsequent theoretical extension
to aging, we investigate our two-time correlation functions out of equilibrium,
which show several qualitatively different behaviors depending on the
parameters in our theory. They exhibit either growing or aging, i.e. power-law
decaying, behaviors for the entire range of our scaling time. Surprisingly, for
some parameter ranges, they exhibit growing at early times as well as aging at
later times.Comment: 1+26 pages, 15 figure
Twinning superlattices in indium phosphide nanowires
Here, we show that we control the crystal structure of indium phosphide (InP)
nanowires by impurity dopants. We have found that zinc decreases the activation
barrier for 2D nucleation growth of zinc-blende InP and therefore promotes the
InP nanowires to crystallise in the zinc blende, instead of the commonly found
wurtzite crystal structure. More importantly, we demonstrate that we can, by
controlling the crystal structure, induce twinning superlattices with
long-range order in InP nanowires. We can tune the spacing of the superlattices
by the wire diameter and the zinc concentration and present a model based on
the cross-sectional shape of the zinc-blende InP nanowires to quantitatively
explain the formation of the periodic twinning.Comment: 18 pages, 4 figure
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