Purdue University

About: Purdue University is a education organization based out in West Lafayette, Indiana, United States. It is known for research contribution in the topics: Population & Heat transfer. The organization has 73219 authors who have published 163563 publications receiving 5775236 citations. The organization is also known as: Purdue & Purdue-West Lafayette.

Solving forward-backward stochastic differential equations explicitly — a four step scheme

Abstract: In this paper we investigate the nature of the adapted solutions to a class of forward-backward stochastic differential equations (SDEs for short) in which the forward equation is non-degenerate. We prove that in this case the adapted solution can always be sought in an “ordinary” sense over an arbitrarily prescribed time duration, via a direct “Four Step Scheme”. Using this scheme, we further prove that the backward components of the adapted solution are determined explicitly by the forward components via the solution of a certain quasilinear parabolic PDE system. Moreover the uniqueness of the adapted solutions (over an arbitrary time duration), as well as the continuous dependence of the solutions on the parameters, can all be proved within this unified framework. Some special cases are studied separately. In particular, we derive a new form of the integral representation of the Clark-Haussmann-Ocone type for functionals (or functions) of diffusions, in which the conditional expectation is no longer needed.

Surface-wave array tomography in SE Tibet from ambient seismic noise and two-station analysis: I - Phase velocity maps

Abstract: SUMMARY Empirical Green’s functions (EGFs) between pairs of seismographs can be estimated from the time derivative of the long-time cross-correlation of ambient seismic noise. These EGFs reveal velocity dispersion at relatively short periods, which can be used to resolve structures in the crust and uppermost mantle better than with traditional surface-wave tomography. We combine Rayleigh-wave dispersion estimates from EGFs and from traditional two-station (TS) analysis into a new approach to surface-wave array tomography with data from dense receiver arrays. We illustrate the methodology with continuous broad-band recordings from a temporary seismographic network on the southeastern part of the Tibetan plateau, in Sichuan and Yunnan provinces, SW China. The EGFs are robust under temporal changes in regional seismicity and the use of either ambient noise (approximated by records without signal from events with magnitude mb ≥ 5 or 4) or surface wave coda produces similar results. The EGFs do not strongly depend on the presence of large earthquakes, but they are not reciprocal for stations aligned in the N‐S direction. This directionality reflects the paucity of seismicity to the north of the array. Using a far-field representation of the surface-wave Green’s function and an image transformation technique, we infer from the EGFs the Rayleigh-wave phase velocity dispersion in the period band from 10‐30 s. A classical TS approach is used to determine Rayleigh-wave phase velocity dispersion between 20‐120 s. Together, they constrain phase velocity variations for T = 10‐120 s, which can be used to study the structure from the crust to the upper mantle. Beneath SE Tibet, short and intermediate period (10‐80 s) phase velocities are prominently low, suggesting that the crust and upper mantle beneath SE Tibet is characterized by slow shear wave propagation.

Theory and Validity of Life Satisfaction Scales

Abstract: National accounts of subjective well-being are being considered and adopted by nations. In order to be useful for policy deliberations, the measures of life satisfaction must be psychometrically sound. The reliability, validity, and sensitivity to change of life satisfaction measures are reviewed. The scales are stable under unchanging conditions, but are sensitive to changes in circumstances in people’s lives. Several types of data indicate that the scales validly reflect the quality of respondents’ lives: 1. Differences between nations in life satisfaction associated with differences in objective conditions, 2. Differences between groups who live in different circumstances, 3. Correlations with nonself-report measures of life satisfaction, 4. Genetic and physiological associations with life satisfaction, 5. Systematic patterns of change in the scales before, during, and after significant life events, and 6. Prediction by life satisfaction scores of future behaviors such as suicide. The life satisfaction scales can be influenced by factors such as question order, current mood, and mode of presentation, but in most cases these can be controlled. Our model of life satisfaction judgments points to the importance of attention, values, standards, and top-down effects. Although the scales are useful in research on individual well-being, there are policy questions that need more analysis and research, such as which types of subjective well-being measures are most relevant to which types of policies, how standards influence scores, and how best to associate the scores with current policy deliberations.

Gender and the emergence of leaders : a meta-analysis

Abstract: In this article, research is reviewed on the emergence of male and female leaders in initially leaderless groups

Mapping and analysis of quantitative trait loci in experimental populations

Abstract: Simple statistical methods for the study of quantitative trait loci (QTL), such as analysis of variance, have given way to methods that involve several markers and high-resolution genetic maps. As a result, the mapping community has been provided with statistical and computational tools that have much greater power than ever before for studying and locating multiple and interacting QTL. Apart from their immediate practical applications, the lessons learnt from this evolution of QTL methodology might also be generally relevant to other types of functional genomics approach that are aimed at the dissection of complex phenotypes, such as microarray assessment of gene expression.