Collective oscillations of a classical gas confined in harmonic traps

Starting from the Boltzmann equation we calculate the frequency and the damping of the monopole and quadrupole oscillations of a classical gas confined in an harmonic potential. The collisional term is treated in the relaxation time approximation and a gaussian ansatz is used for its evaluation. Our approach provides an explicit description of the transition between the hydrodynamic and collisionless regimes in both spherical and deformed traps. The predictions are compared with the results of a numerical simulation.Comment: 6 pages, revtex, 2 figures include

Block orthogonal polynomials: I. Definition and properties

Constrained orthogonal polynomials have been recently introduced in the study of the Hohenberg-Kohn functional to provide basis functions satisfying particle number conservation for an expansion of the particle density. More generally, we define block orthogonal (BO) polynomials which are orthogonal, with respect to a first Euclidean scalar product, to a given $i$-dimensional subspace ${\cal E}_i$ of polynomials associated with the constraints. In addition, they are mutually orthogonal with respect to a second Euclidean scalar product. We recast the determination of these polynomials into a general problem of finding particular orthogonal bases in an Euclidean vector space endowed with distinct scalar products. An explicit two step Gram-Schmidt orthogonalization (G-SO) procedure to determine these bases is given. By definition, the standard block orthogonal (SBO) polynomials are associated with a choice of ${\cal E}_i$ equal to the subspace of polynomials of degree less than $i$. We investigate their properties, emphasizing similarities to and differences from the standard orthogonal polynomials. Applications to classical orthogonal polynomials will be given in forthcoming papers.Comment: This is a reduced version of the initial manuscript, the number of pages being reduced from 34 to 2

Periodontal Pathogens and Risk of Incident Cancer in Postmenopausal Females: The Buffalo OsteoPerio Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/142052/1/jper0257.pd

Private‐Public Partnership: improved bean seed access in Malawi

This initiative was aimed at demonstrating that the public‐private partnerships in the bean seed value chain can make a difference to avail bean seed of improved varieties to farmers. The common beans is an import food crop covering an estimated area of 260,000 ha in Malawi in 2010. However the reliable system for access to quality seed of improved bean varieties is still constrained by lack of sustainable supply. Through a public‐private partnership (PPP), CIAT‐DARS and DS Ltd shared seed system related roles, which generated about 1040 tons between 2009‐11, reaching 590,000 smallscale farmers with seed of improved bean varieties. An evaluation carried out to assess the outcomes, revealed that sustained provision of foundation seeds through diversified sources (both private and public), technical support/backstopping from extension staff and researchers to private seed suppliers was essential in establishing an efficient and sustainable seed supply system

Association Between Metabolic Syndrome and Periodontal Disease Measures in Postmenopausal Women: The Buffalo OsteoPerio Study

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141377/1/jper1489.pd

Association of Plasma 25â Hydroxyvitamin D Concentrations and Pathogenic Oral Bacteria in Postmenopausal Females

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141146/1/jper0944.pd

Explorations, Vol. 6, No. 2

Cover: Untitled #13, Series 2, chalk on paper, by Ronald Ghiz, Associate Professor of Art at the University of Maine. Articles include: Editorial Overview: in this issue, by Carole J. Bombard Save the Planet . . . please, by Nick Houtman Research and Public Service Recognizing Leadership, Pioneering, and Productivity, Herb Hidu and Stephen Norton Private Assistance for Maine’s Hungry, by William H. Whitaker and Jean M. Andrews The Ugly Faces of Hunger Explaining the Iranian Revolution, by Henry Munson, Jr. Biological Clocks: timing is everything—and everywhere, by Jamie Watler Love of Glory and the Common Good: Periclean Democracy and Athenian Tyranny in Thucydides, by Michael Palmer Tools of the Trade: Technology Usage and Financial Performance in Small Business, by Diane J. Garsombke and Thomas W. Garsombk

Stratospheric ozone chemistry feedbacks are not critical for the determination of climate sensitivity in CESM1(WACCM)

The Community Earth System Model‐Whole Atmosphere Community Climate Model (CESM1‐WACCM) is used to assess the importance of including chemistry feedbacks in determining the equilibrium climate sensitivity (ECS). Two 4×CO2 model experiments were conducted: one with interactive chemistry and one with chemical constituents other than CO2 held fixed at their preindustrial values. The ECS determined from these two experiments agrees to within 0.01 K. Similarly, the net feedback parameter agrees to within 0.01 W m−2 K−1. This agreement occurs in spite of large changes in stratospheric ozone found in the simulation with interactive chemistry: a 30% decrease in the tropical lower stratosphere and a 40% increase in the upper stratosphere, broadly consistent with other published estimates. Off‐line radiative transfer calculations show that ozone changes alone account for the difference in radiative forcing. We conclude that at least for determining global climate sensitivity metrics, the exclusion of chemistry feedbacks is not a critical source of error in CESM

Topology of Chaotic Mixing Patterns

A stirring device consisting of a periodic motion of rods induces a mapping of the fluid domain to itself, which can be regarded as a homeomorphism of a punctured surface. Having the rods undergo a topologically-complex motion guarantees at least a minimum amount of stretching of material lines, which is important for chaotic mixing. We use topological considerations to describe the nature of the injection of unmixed material into a central mixing region, which takes place at injection cusps. A topological index formula allow us to predict the possible types of unstable foliations that can arise for a fixed number of rods.Comment: 15 pages, 13 figures, RevTeX4 macros. Final versio

Gene expression profiling reveals a conserved microglia signature in larval zebrafish

International audienceMicroglia are the resident macrophages of the brain. Over the past decade, our understanding of the function of these cells has significantly improved. Microglia do not only play important roles in the healthy brain but are involved in almost every brain pathology. Gene expression profiling allowed to distinguish microglia from other macro-phages and revealed that the full microglia signature can only be observed in vivo. Thus, animal models are irreplaceable to understand the function of these cells. One of the popular models to study microglia is the zebrafish larva. Due to their optical transparency and genetic accessibility, zebrafish larvae have been employed to understand a variety of microglia functions in the living brain. Here, we performed RNA sequencing of larval zebrafish microglia at different developmental time points: 3, 5, and 7 days post fertilization (dpf). Our analysis reveals that larval zebrafish microglia rapidly acquire the core microglia signature and many typical microglia genes are expressed from 3 dpf onwards. The majority of changes in gene expression happened between 3 and 5 dpf, suggesting that differentiation mainly takes place during these days. Furthermore, we compared the larval microglia transcriptome to published data sets of adult zebrafish microglia, mouse microglia, and human microglia. Larval microglia shared a significant number of expressed genes with their adult counterparts in zebrafish as well as with mouse and human microglia. In conclusion, our results show that larval zebrafish microglia mature rapidly and express the core microglia gene signature that seems to be conserved across species. K E Y W O R D S brain, evolution, microglia, RNA sequencing, transcriptome, zebrafis