Adolescent depressive symptoms in India, Australia and USA: Exploratory Structural Equation Modelling of cross-national invariance and predictions by gender and age

Background The present study compares depressive symptoms in adolescents from three countries: Mumbai, India; Seattle, United States; and Melbourne, Australia measured using the Short Moods and Feelings Questionnaire (SMFQ). The study cross nationally compares SMFQ depressive symptom responses by age and gender. Methods Data from a cross-nationally matched survey were used to compare factorial and measurement characteristics from samples of students from Grade 7 and 9 in Mumbai, India (n=3268) with the equivalent cohorts in the Washington State, USA (n=1907) and Victoria, Australia (n=1900). Exploratory Structural Equation Modelling (ESEM) was used to cross-nationally examine factor structure and measurement invariance. Results A number of reports suggesting that SMFQ is uni-dimensional were not supported in findings from any country. A model with two factors was a better fit and suggested a first factor clustering symptoms that were affective and physiologically based symptoms and a second factor of self-critical, cognitive symptoms. The two-factor model showed convincing cross national configural invariance and acceptable measurement invariance. The present findings revealed that adolescents in Mumbai, India, reported substantially higher depressive symptoms in both factors, but particularly for the self-critical dimension, as compared to their peers in Australia and the USA and that males in Mumbai report high levels of depressive symptoms than females in Mumbai. Limitations the cross sectional study collected data for adolescents in Melbourne and Seattle in 2002 and the data for adolescents in Mumbai was obtained in 2010–2011 Conclusions These findings suggest that previous findings in developed nations of higher depressive symptoms amongst females compared to males may have an important cultural component and cannot be generalised as a universal feature of adolescent development

Dairy marketing in sub-Saharan Africa. Proceedings of a symposium

The main aim of the symposium is to develop a comprehensive overview of what is already known about dairy marketing systems and policies in sub-Saharan Africa and to identify key research problems so as to facilitate a coordinated research effort among interested parties. The symposium was organised in six parts: A general review of dairy production, marketing, international trade and food aid in sub-Saharan Africa; dairy technologies and dairy processing, with a focus on supporting smallholder production and marketing; dairy demand and consumption patterns; marketing efficiency; dairy marketing and dairy policies in various countries; and primary data collection problems, focusing on survey planning and non-sampling errors in dairy marketing research. The symposium do not address methodological issues and problems in dairy marketing research

Evidence for the Gompertz Curve in the Income Distribution of Brazil 1978-2005

This work presents an empirical study of the evolution of the personal income distribution in Brazil. Yearly samples available from 1978 to 2005 were studied and evidence was found that the complementary cumulative distribution of personal income for 99% of the economically less favorable population is well represented by a Gompertz curve of the form $G(x)=\exp [\exp (A-Bx)]$, where $x$ is the normalized individual income. The complementary cumulative distribution of the remaining 1% richest part of the population is well represented by a Pareto power law distribution $P(x)= \beta x^{-\alpha}$. This result means that similarly to other countries, Brazil's income distribution is characterized by a well defined two class system. The parameters $A$, $B$, $\alpha$, $\beta$ were determined by a mixture of boundary conditions, normalization and fitting methods for every year in the time span of this study. Since the Gompertz curve is characteristic of growth models, its presence here suggests that these patterns in income distribution could be a consequence of the growth dynamics of the underlying economic system. In addition, we found out that the percentage share of both the Gompertzian and Paretian components relative to the total income shows an approximate cycling pattern with periods of about 4 years and whose maximum and minimum peaks in each component alternate at about every 2 years. This finding suggests that the growth dynamics of Brazil's economic system might possibly follow a Goodwin-type class model dynamics based on the application of the Lotka-Volterra equation to economic growth and cycle.Comment: 22 pages, 15 figures, 4 tables. LaTeX. Accepted for publication in "The European Physical Journal B

Fractional Langevin equation

We investigate fractional Brownian motion with a microscopic random-matrix model and introduce a fractional Langevin equation. We use the latter to study both sub- and superdiffusion of a free particle coupled to a fractal heat bath. We further compare fractional Brownian motion with the fractal time process. The respective mean-square displacements of these two forms of anomalous diffusion exhibit the same power-law behavior. Here we show that their lowest moments are actually all identical, except the second moment of the velocity. This provides a simple criterion which enables to distinguish these two non-Markovian processes.Comment: 4 page

Origins of the Ambient Solar Wind: Implications for Space Weather

The Sun's outer atmosphere is heated to temperatures of millions of degrees, and solar plasma flows out into interplanetary space at supersonic speeds. This paper reviews our current understanding of these interrelated problems: coronal heating and the acceleration of the ambient solar wind. We also discuss where the community stands in its ability to forecast how variations in the solar wind (i.e., fast and slow wind streams) impact the Earth. Although the last few decades have seen significant progress in observations and modeling, we still do not have a complete understanding of the relevant physical processes, nor do we have a quantitatively precise census of which coronal structures contribute to specific types of solar wind. Fast streams are known to be connected to the central regions of large coronal holes. Slow streams, however, appear to come from a wide range of sources, including streamers, pseudostreamers, coronal loops, active regions, and coronal hole boundaries. Complicating our understanding even more is the fact that processes such as turbulence, stream-stream interactions, and Coulomb collisions can make it difficult to unambiguously map a parcel measured at 1 AU back down to its coronal source. We also review recent progress -- in theoretical modeling, observational data analysis, and forecasting techniques that sit at the interface between data and theory -- that gives us hope that the above problems are indeed solvable.Comment: Accepted for publication in Space Science Reviews. Special issue connected with a 2016 ISSI workshop on "The Scientific Foundations of Space Weather." 44 pages, 9 figure

Moral courage in the workplace: moving to and from the desire and decision to act

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72135/1/j.1467-8608.2007.00484.x.pd

Miniband-related 1.4–1.8 μm luminescence of Ge/Si quantum dot superlattices

The luminescence properties of highly strained, Sb-doped Ge/Si multi-layer heterostructures with incorporated Ge quantum dots (QDs) are studied. Calculations of the electronic band structure and luminescence measurements prove the existence of an electron miniband within the columns of the QDs. Miniband formation results in a conversion of the indirect to a quasi-direct excitons takes place. The optical transitions between electron states within the miniband and hole states within QDs are responsible for an intense luminescence in the 1.4–1.8 µm range, which is maintained up to room temperature. At 300 K, a light emitting diode based on such Ge/Si QD superlattices demonstrates an external quantum efficiency of 0.04% at a wavelength of 1.55 µm