Time filter

Source Type

New York City, NY, United States

Barnard College is a private women's liberal arts college and one of the Seven Sisters. Founded in 1889, it has been affiliated with Columbia University since 1900. Barnard's 4-acre campus stretches along Broadway between 116th and 120th Streets in the Morningside Heights neighborhood in the borough of Manhattan, in New York City. It is directly adjacent to Columbia's campus and near several other academic institutions and has been used by Barnard since 1898. Wikipedia.

Halpin-Healy T.,Barnard College
Physical Review Letters | Year: 2012

We examine numerically the zero-temperature (2+1)-dimensional directed polymer in a random medium, along with several of its brethren via the Kardar-Parisi-Zhang (KPZ) equation. Using finite-size and KPZ scaling Ansätze, we extract the universal distributions controlling fluctuation phenomena in this canonical model of nonequilibrium statistical mechanics. Specifically, we study point-point, point-line, and point-plane directed polymer geometries, scenarios which yield higher-dimensional analogs of the Tracy-Widom distributions of random matrix theory. Our analysis represents a robust, multifaceted numerical characterization of the 2+1 KPZ universality class and its limit distributions. © 2012 American Physical Society. Source

Today the commodity circuit for specialty coffee seems to be made up of socially conscious consumers, well-meaning and politically engaged roasters and small companies, and poor yet ecologically noble producers who want to take part in the flows of global capital, while at the same time living in close harmony with the natural world. This paper examines how these actors are produced by changes in the global economy that are sometimes referred to as neoliberalism. It also shows how images of these actors are produced and what the material effects of those images are. It begins with a description of how generations are understood and made by marketers. Next it shows how coffee production in Papua New Guinea, especially Fair Trade and organic coffee production, is turned into marketing narratives meant to appeal to particular consumers. Finally, it assesses the success of the generational-based marketing of Papua New Guinea-origin, Fair Trade and organic coffees, three specialty coffee types that are marketed heavily to the "Millenial generation", people born between 1983 and 2000. © 2010 The Author Journal compilation © 2010 Editorial Board of Antipode. Source

Bauer E.P.,Barnard College
Behavioural Brain Research | Year: 2015

This review describes the latest developments in our understanding of how the serotonergic system modulates Pavlovian fear conditioning, fear expression and fear extinction. These different phases of classical fear conditioning involve coordinated interactions between the extended amygdala, hippocampus and prefrontal cortices. Here, I first define the different stages of learning involved in cued and context fear conditioning and describe the neural circuits underlying these processes. The serotonergic system can be manipulated by administering serotonin receptor agonists and antagonists, as well as selective serotonin reuptake inhibitors (SSRIs), and these can have significant effects on emotional learning and memory. Moreover, variations in serotonergic genes can influence fear conditioning and extinction processes, and can underlie differential responses to pharmacological manipulations. This research has considerable translational significance as imbalances in the serotonergic system have been linked to anxiety and depression, while abnormalities in the mechanisms of conditioned fear contribute to anxiety disorders. © 2014 . Source

Halpin-Healy T.,Barnard College
Physical Review E - Statistical, Nonlinear, and Soft Matter Physics | Year: 2013

Following our numerical work focused upon the 2+1 Kardar-Parisi-Zhang (KPZ) equation with flat initial condition, we return here to study, in depth, the three-dimensional (3D) radial KPZ problem, comparing common scaling phenomena exhibited by the pt-pt directed polymer in a random medium (DPRM), the stochastic heat equation (SHE) with multiplicative noise in three dimensions, and kinetic roughening phenomena associated with 3D Eden clusters. Examining variants of the 3D DPRM, as well as numerically integrating, via the Itô prescription, the constrained SHE for different values of the KPZ coupling, we provide strong evidence for universality within this 3D KPZ class, revealing shared values for the limit distribution skewness and kurtosis, along with universal first and second moments. Our numerical analysis of the 3D SHE, well flanked by the DPRM results, appears without precedent in the literature. We consider, too, the 2+1 KPZ equation in the deeply evolved kinetically roughened stationary state, extracting the essential limit distribution characterizing fluctuations therein, revealing a higher-dimensional relative of the 1+1 KPZ Baik-Rains distribution. Complementary, corroborative findings are provided via the Gaussian DPRM, as well as the restricted-solid-on-solid model of stochastic growth, stalwart members of the 2+1 KPZ class. Next, contact is made with a recent nonperturbative, field-theoretic renormalization group calculation for the key universal amplitude ratio in this context. Finally, in the crossover from transient to stationary-state statistics, we observe a higher dimensional manifestation of the skewness minimum discovered by Takeuchi in 1+1 KPZ class liquid-crystal experiments. © 2013 American Physical Society. Source

Friedberg R.,Barnard College
Annals of Physics | Year: 2010

A new formula has been given recently by A.A. Svidzinsky and M.O. Scully to describe the temporal evolution of the excitation function β fenced(t, over(r, →)) in a large sphere satisfying the Markov condition after excitation by a single photon. This formula is based on a physically reasonable Ansatz from which differential equations are inferred for the undetermined radial functions in the Ansatz. The solution to these differential equations leads to the formula for β. Numerical calculations from this formula yield a value ∼10% for the maximum probability of occupancy of secondary excited states. In this paper, we refine the formula of Svidzinsky and Scully by allowing the radial functions in the Ansatz to depend on the angular index l of the spherical Bessel functions. By using the Debye formula for the asymptotic behavior of jl (u) for large l as well as u, we obtain differential equations in each angular sector, similar to theirs but with a dependence on l. The solution to these equations yields our improved formula, from which we calculate 17.1% for the maximum probability of secondary excited states. © 2009 Elsevier Inc. All rights reserved. Source

Discover hidden collaborations