A College For Appalachia: Alice Lloyd on Caney Creek

Alice Spencer Geddes Lloyd was a New England woman with a mission in life. In 1916 she settled on Caney Creek in Eastern Kentucky, determined to bring higher education to this remote corner of Appalachia. The school she founded, now Alice Lloyd College, continues to serve the area and its people and to stand as a tribute to Lloyd’s remarkable energy, determination, and vision. Lloyd\u27s program combined a rigorous academic curriculum with an intense effort to instill a sense of service in the school\u27s graduates. This education was provided free and required only that the students abide by Lloyd\u27s strict rules of conduct and pledge to remain in the mountains after graduating. In the first full-scale study of Lloyd\u27s life and work and the institution she founded, David Searles shows how this courageous and complex woman struggled throughout her long life against seemingly insurmountable odds to create an institution dedicated to improving life in Appalachia. But, as he acknowledges, Lloyd\u27s fundraising activities relied on harmful stereotypes that caused resentment among her mountain neighbors, and she often angered others working in the mountains. Despite the negative aspects of Lloyd\u27s activities, Searles casts serious doubt on the now fashionable conclusion that the women who came to the mountains to do good created more problems than they solved. Lloyd\u27s story, he argues, demonstrates that much good was indeed accomplished and that the people of the mountains recognized and appreciated her achievement. P. David Searles is a former director of the Peace Corps and former deputy chairman of the National Endowment for the Arts.https://uknowledge.uky.edu/upk_higher_education/1009/thumbnail.jp

The Glass Transition and the Jarzynski Equality

A simple model featuring a double well potential is used to represent a liquid that is quenched from an ergodic state into a history dependent glassy state. Issues surrounding the application of the Jarzynski Equality to glass formation are investigated. We demonstrate that the Jarzynski Equality gives the free energy difference between the initial state and the state we would obtain if the glass relaxed to true thermodynamic equilibrium. We derive new variations of the Jarzynski Equality which are relevant to the history dependent glassy state rather than the underlying equilibrium state. It is shown how to compute the free energy differences for the nonequilibrium history dependent glassy state such that it remains consistent with the standard expression for the entropy and with the second law inequality.Comment: 16 pages, 5 figure

All Through the Love of You!

https://digitalcommons.library.umaine.edu/mmb-vp/3933/thumbnail.jp

The Steady State Fluctuation Relation for the Dissipation Function

We give a proof of transient fluctuation relations for the entropy production (dissipation function) in nonequilibrium systems, which is valid for most time reversible dynamics. We then consider the conditions under which a transient fluctuation relation yields a steady state fluctuation relation for driven nonequilibrium systems whose transients relax, producing a unique nonequilibrium steady state. Although the necessary and sufficient conditions for the production of a unique nonequilibrium steady state are unknown, if such a steady state exists, the generation of the steady state fluctuation relation from the transient relation is shown to be very general. It is essentially a consequence of time reversibility and of a form of decay of correlations in the dissipation, which is needed also for, e.g., the existence of transport coefficients. Because of this generality the resulting steady state fluctuation relation has the same degree of robustness as do equilibrium thermodynamic equalities. The steady state fluctuation relation for the dissipation stands in contrast with the one for the phase space compression factor, whose convergence is problematic, for systems close to equilibrium. We examine some model dynamics that have been considered previously, and show how they are described in the context of this work.Comment: 30 pages, 1 figur

Multiplex SNP Discrimination

Multiplex hybridization reactions of perfectly matched duplexes and duplexes containing a single basepair mismatch (SNPs) were investigated on DNA microarrays. Effects of duplex length, G-C percentage, and relative position of the SNP on duplex hybridization and SNP resolution were determined. Our theoretical model of multiplex hybridization accurately predicts observed results and implicates target concentration as a critical variable in multiplex SNP detection

Moderated peer assessment of individual contribution to group work

UCL Engineering trains students to use engineering knowledge within extended group practical activities to prepare them for their careers after graduation. However, despite the substantial educational benefits of getting students to work in teams, providing individual assessment can be challenging. Students frequently express dissatisfaction if all members of a team are given the same mark regardless of the individual effort. Here, we aim to promote student engagement and improve student experience during group work by giving each student an individual mark. The individual mark results from multiplying the overall “group mark” by a personal contribution factor. This personal contribution is assessed directly by peers, who are aware of each team member’s contribution, encouraging self-reflection, and moderated by tutors when necessary. This practice has been well received by students in other universities. We are working with a student committee to identify and evaluate various methods and e-learning systems that would aid us to run this practice efficiently even for large numbers of students. This includes rules to flag cases requiring moderation. This project, partially funded by ELDG 2015, fits with our aim of increasing students’ satisfaction and engagement with assessment. We have combined it with our ‘360 degrees peer assessment method’, which we presented at last year’s conference, to provide a reliable and individual peer assessment of group work. We provide a novel approach to group assessment which encourages self-reflection and is intended to improve the learning experience and student satisfaction during group work, in line with UCL 2034

On the Fluctuation Relation for Nose-Hoover Boundary Thermostated Systems

We discuss the transient and steady state fluctuation relation for a mechanical system in contact with two deterministic thermostats at different temperatures. The system is a modified Lorentz gas in which the fixed scatterers exchange energy with the gas of particles, and the thermostats are modelled by two Nos\'e-Hoover thermostats applied at the boundaries of the system. The transient fluctuation relation, which holds only for a precise choice of the initial ensemble, is verified at all times, as expected. Times longer than the mesoscopic scale, needed for local equilibrium to be settled, are required if a different initial ensemble is considered. This shows how the transient fluctuation relation asymptotically leads to the steady state relation when, as explicitly checked in our systems, the condition found in [D.J. Searles, {\em et al.}, J. Stat. Phys. 128, 1337 (2007)], for the validity of the steady state fluctuation relation, is verified. For the steady state fluctuations of the phase space contraction rate \zL and of the dissipation function \zW, a similar relaxation regime at shorter averaging times is found. The quantity \zW satisfies with good accuracy the fluctuation relation for times larger than the mesoscopic time scale; the quantity \zL appears to begin a monotonic convergence after such times. This is consistent with the fact that \zW and \zL differ by a total time derivative, and that the tails of the probability distribution function of \zL are Gaussian.Comment: Major revision. Fig.10 was added. Version to appear in Journal of Statistical Physic

DNA multiplex hybridization on microarrays and thermodynamic stability in solution: a direct comparison

Hybridization intensities of 30 distinct short duplex DNAs measured on spotted microarrays, were directly compared with thermodynamic stabilities measured in solution. DNA sequences were designed to promote formation of perfect match, or hybrid duplexes containing tandem mismatches. Thermodynamic parameters ΔH°, ΔS° and ΔG° of melting transitions in solution were evaluated directly using differential scanning calorimetry. Quantitative comparison with results from 63 multiplex microarray hybridization experiments provided a linear relationship for perfect match and most mismatch duplexes. Examination of outliers suggests that both duplex length and relative position of tandem mismatches could be important factors contributing to observed deviations from linearity. A detailed comparison of measured thermodynamic parameters with those calculated using the nearest-neighbor model was performed. Analysis revealed the nearest-neighbor model generally predicts mismatch duplexes to be less stable than experimentally observed. Results also show the relative stability of a tandem mismatch is highly dependent on the identity of the flanking Watson–Crick (w/c) base pairs. Thus, specifying the stability contribution of a tandem mismatch requires consideration of the sequence identity of at least four base pair units (tandem mismatch and flanking w/c base pairs). These observations underscore the need for rigorous evaluation of thermodynamic parameters describing tandem mismatch stability

Independence of the transient fluctuation theorem to thermostatting details

The dependence of fluctuation theorem on the precise mathematical details of thermostatting mechanism for an infinite class of fictious time reversible deterministic thermostats was analyzed. Theoretical and numerical analysis were carried out for a class of time reversible deterministic thermostats that fix various moments of the momentum distribution. In this large thermostat the transient fluctuation theorem (TFT) was found dependent of the precise moment that the thermostat fixes. The study shows that in a non-equilibrium system in contact with a thermostat and having large degrees of freedom, the transient fluctuation relation is insensitive to the details of thermostatting mechanisms

Lyapunov Exponent Pairing for a Thermostatted Hard-Sphere Gas under Shear in the Thermodynamic Limit

We demonstrate why for a sheared gas of hard spheres, described by the SLLOD equations with an iso-kinetic Gaussian thermostat in between collisions, deviations of the conjugate pairing rule for the Lyapunov spectrum are to be expected, employing a previous result that for a large number of particles $N$, the iso-kinetic Gaussian thermostat is equivalent to a constant friction thermostat, up to $1/\sqrt{N}$ fluctuations. We also show that these deviations are at most of the order of the fourth power in the shear rate.Comment: 4 pages, to appear in Rapid Comm., Phys. Rev.