Kinetic analysis using square-wave stimulation in modulation excitation spectroscopy: Mixing property of a flow-through PM-IRRAS cell

Abstract Square-wave stimulation used in modulation excitation spectroscopy [D. Baurecht, U.P. Fringeli, Rev. Sci. Instrum. 72 (2001) 3782] can have significant advantages over a simple sinusoidal-wave due to the high odd-frequency terms contained in square-wave, particularly when a system response is close to linear. Phase-sensitive detection (PSD) affords separating the signals of the different frequency terms with a high signal-to-noise ratio by averaging a number of modulation cycles. A modulation excitation experiment applying square-wave stimulation provides the same information as several experiments applying sinusoidal-wave stimulations at the same frequency as the square-wave stimulation and at higher frequencies. The amplitude and the phase lag of a response obtained by PSD at fundamental and higher frequencies using square-wave stimulation are related to the ones obtained by sinusoidal-wave stimulation using transfer function of a general system. Mixing property of a PM-IRRAS (polarization-modulation infrared reflection-absorption spectroscopy) flow-through cell was studied by a simple mixing tank model using square-wave concentration stimulation. The advantages of square-wave stimulation are shown by the characterization of the mixing property

Nonequilibrium candidate Monte Carlo: A new tool for efficient equilibrium simulation

Metropolis Monte Carlo simulation is a powerful tool for studying the equilibrium properties of matter. In complex condensed-phase systems, however, it is difficult to design Monte Carlo moves with high acceptance probabilities that also rapidly sample uncorrelated configurations. Here, we introduce a new class of moves based on nonequilibrium dynamics: candidate configurations are generated through a finite-time process in which a system is actively driven out of equilibrium, and accepted with criteria that preserve the equilibrium distribution. The acceptance rule is similar to the Metropolis acceptance probability, but related to the nonequilibrium work rather than the instantaneous energy difference. Our method is applicable to sampling from both a single thermodynamic state or a mixture of thermodynamic states, and allows both coordinates and thermodynamic parameters to be driven in nonequilibrium proposals. While generating finite-time switching trajectories incurs an additional cost, driving some degrees of freedom while allowing others to evolve naturally can lead to large enhancements in acceptance probabilities, greatly reducing structural correlation times. Using nonequilibrium driven processes vastly expands the repertoire of useful Monte Carlo proposals in simulations of dense solvated systems

Hot spots of glacier mass balance variability in Central Asia

The Tien Shan and Pamir mountains host over 28,000 glaciers providing essential water resources for increasing water demand in Central Asia. A disequilibrium between glaciers and climate affects meltwater release to Central Asian rivers, challenging the region's water availability. Previous research has neglected temporal variability. We present glacier mass balance estimates based on transient snowline and geodetic surveys with unprecedented spatiotemporal resolution from 1999/00 to 2017/18. Our results reveal spatiotemporal heterogeneity characterized by two mass balance clusters: (a) positive, low variability, and (b) negative, high variability. This translates into variable glacial meltwater release (≈1–16%) of annual river runoff for two watersheds. Our study reveals more complex climate forcing-runoff responses and importance of glacial meltwater variability for the region than suggested previously.ISSN:0094-8276ISSN:1944-800

Distributed global debris thickness estimates reveal debris significantly impacts glacier mass balance

International audienc

Socio-Economic Inequalities in the Use of Postnatal Care in India

OBJECTIVES: First, our objective was to estimate socio-economic inequalities in the use of postnatal care (PNC) compared with those in the use of care at birth and antenatal care. Second, we wanted to compare inequalities in the use of PNC between facility births and home births and to determine inequalities in the use of PNC among mothers with high-risk births. METHODS AND FINDINGS: Rich-poor ratios and concentration indices for maternity care were estimated using the third round of the District Level Household Survey conducted in India in 2007-08. Binary logistic regression models were used to examine the socio-economic inequalities associated with use of PNC after adjusting for relevant socio-economic and demographic characteristics. PNC for both mothers and newborns was substantially lower than the care received during pregnancy and child birth. Only 44% of mothers in India at the time of survey received any care within 48 hours after birth. Likewise, only 45% of newborns received check-up within 24 hours of birth. Mothers who had home births were significantly less likely to have received PNC than those who had facility births, with significant differences across the socio-economic strata. Moreover, the rich-poor gap in PNC use was significantly wider for mothers with birth complications. CONCLUSIONS: PNC use has been unacceptably low in India given the risks of mortality for mothers and babies shortly after birth. However, there is evidence to suggest that effective use of pregnancy and childbirth care in health facilities led to better PNC. There are also significant socio-economic inequalities in access to PNC even for those accessing facility-based care. The coverage of essential PNC is inadequate, especially for mothers from economically disadvantaged households. The findings suggest the need for strengthening PNC services to keep pace with advances in coverage for care at birth and prenatal services in India through targeted policy interventions

Predictors of mortality among elderly people living in a south Indian urban community; a 10/66 Dementia Research Group prospective population-based cohort study

<p>Abstract</p> <p>Background</p> <p>Eighty percent of deaths occur in low and middle income countries (LMIC), where chronic diseases are the leading cause. Most of these deaths are of older people, but there is little information on the extent, pattern and predictors of their mortality. We studied these among people aged 65 years and over living in urban catchment areas in Chennai, south India.</p> <p>Methods</p> <p>In a prospective population cohort study, 1005 participants were followed-up after three years. Baseline assessment included sociodemographic and socioeconomic characteristics, health behaviours, physical, mental and cognitive disorders, disability and subjective global health.</p> <p>Results</p> <p>At follow-up, 257 (25.6%) were not traced. Baseline characteristics were similar to the 748 whose vital status was ascertained; 154 (20.6%) had died. The mortality rate was 92.5/1000 per annum for men and 51.0/1000 per annum for women. Adjusting for age and sex, mortality was associated with older age, male sex, having no friends, physical inactivity, smaller arm circumference, dementia, depression, poor self-rated health and disability. A parsimonious model included, in order of aetiologic force, male sex, smaller arm circumference, age, disability, and dementia. The total population attributable risk fraction was 0.90.</p> <p>Conclusion</p> <p>A balanced approach to prevention of chronic disease deaths requires some attention to proximal risk factors in older people. Smoking and obesity seem much less relevant than in younger people. Undernutrition is preventable. While dementia makes the largest contribution to disability and dependency, comorbidity is the rule, and more attention should be given to the chronic care needs of those affected, and their carers.</p

The solar WIND and suprathermal ion composition investigation on the WIND spacecraft

The Solar Wind and Suprathermal Ion Composition Experiment (SMS) on WIND is designed to determine uniquely the elemental, isotopic, and ionic-charge composition of the solar wind, the temperatures and mean speeds of all major solar-wind ions, from H through Fe, at solar wind speeds ranging from 175 kms −1 (protons) to 1280 kms −1 (Fe +8 ), and the composition, charge states as well as the 3-dimensional distribution functions of suprathermal ions, including interstellar pick-up He + , of energies up to 230 keV/e. The experiment consists of three instruments with a common Data Processing Unit. Each of the three instruments uses electrostatic analysis followed by a time-of-flight and, as required, an energy measurement. The observations made by SMS will make valuable contributions to the ISTP objectives by providing information regarding the composition and energy distribution of matter entering the magnetosphere. In addition SMS results will have an impact on many areas of solar and heliospheric physics, in particular providing important and unique information on: (i) conditions and processes in the region of the corona where the solar wind is accelerated; (ii) the location of the source regions of the solar wind in the corona; (iii) coronal heating processes; (iv) the extent and causes of variations in the composition of the solar atmosphere; (v) plasma processes in the solar wind; (vi) the acceleration of particles in the solar wind; and (vii) the physics of the pick-up process of interstellar He as well as lunar particles in the solar wind, and the isotopic composition of interstellar helium.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43776/1/11214_2004_Article_BF00751327.pd