Balancing Local Order and Long-Ranged Interactions in the Molecular Theory of Liquid Water

A molecular theory of liquid water is identified and studied on the basis of computer simulation of the TIP3P model of liquid water. This theory would be exact for models of liquid water in which the intermolecular interactions vanish outside a finite spatial range, and therefore provides a precise analysis tool for investigating the effects of longer-ranged intermolecular interactions. We show how local order can be introduced through quasi-chemical theory. Long-ranged interactions are characterized generally by a conditional distribution of binding energies, and this formulation is interpreted as a regularization of the primitive statistical thermodynamic problem. These binding-energy distributions for liquid water are observed to be unimodal. The gaussian approximation proposed is remarkably successful in predicting the Gibbs free energy and the molar entropy of liquid water, as judged by comparison with numerically exact results. The remaining discrepancies are subtle quantitative problems that do have significant consequences for the thermodynamic properties that distinguish water from many other liquids. The basic subtlety of liquid water is found then in the competition of several effects which must be quantitatively balanced for realistic results.Comment: 8 pages, 6 figure

Final state interactions in two-particle interferometry

We reconsider the influence of two-particle final state interactions (FSI) on two-particle Bose-Einstein interferometry. We concentrate in particular on the problem of particle emission at different times. Assuming chaoticity of the source, we derive a new general expression for the symmetrized two-particle cross section. We discuss the approximations needed to derive from the general result the Koonin-Pratt formula. Introducing a less stringent version of the so-called smoothness approximation we also derive a more accurate formula. It can be implemented into classical event generators and allows to calculate FSI corrected two-particle correlation functions via modified Bose-Einstein "weights".Comment: 12 pages RevTeX, 2 ps-figures included, submitted to Phys. Rev.

Introducing First Year Medical Students to Personalized Medicine Concepts in a Small Group Activity

Presented as a Poster Presentation at 2020 IUSM Education Day.An individuals’ genetic profile is becomingly an increasingly important parameter in healthcare decisions. This small group activity was developed to introduce first year medical students in the Molecules to Cells and Tissues course to the concept and significance of Pharmacogenomics and personalized medicine. Additionally, this activity provided students with an opportunity to work with a large dataset and use the information to impact clinical decision making. This activity has two cases, takes student groups approximately 2 hours to complete, and requires internet access. Case materials are available through the learning management system Canvas, and include open-ended questions to guide students through the cases. In these cases students explore the functional significance of different alleles of a panel of cytochrome P450 genes. The group activity has the students examine a large data set of cytochrome P450 genes and cognate alleles to determine their prevalence in the local population and calculate the individuals’ gene scores. The students are then asked to explain the impact of the genotype (or gene score) on the resulting patient phenotype (i.e. the functional significance of the genotype). The first case involves a breast cancer survivor support group in which patients taking Taxol discuss lack of adequate pain relief from opioids and the potential impact of concomitant use of natural compounds/supplements on drug metabolism. The second case involves a patient presenting with recurrent stroke-like symptoms despite being on the anticoagulant medication clopidogrel. The patient is initially suspected to be non-compliant, but is later determined to be a poor metabolizer of the anticoagulant clopidogrelto its active form thus decreasing its efficacy. The expertise of the IUSM Medical Genetics research faculty was leveraged to provide a large data set of cytochrome P450 genes and cognate alleles. The selection of cytochrome P450 was based upon delivering content focused on the biochemistry of the enzyme system and provided an opportunity to highlight the drug interaction database available through IUSM Clinical Pharmacology (The FlockhartTable™ ; https://drug-interactions.medicine.iu.edu/). The addition of natural compounds was to draw students’ attention to the Natural Medicines database, which is the recommended source for evidence-based data on complementary and alternative medicine. Natural Medicines is available through the Ruth Lilly Medical Library and can be searched by substance or condition. It provides both a summary of the literature available on substances as well as the level of evidence or quality of studies done on the substance

Early evolution of electron cyclotron driven current during suppression of tearing modes in a circular tokamak

When electron cyclotron (EC) driven current is first applied to the inside of a magnetic island, the current spreads throughout the island and after a short period achieves a steady level. Using a two equation fluid model for the EC current that allows us to examine this early evolution in detail, we analyze high-resolution simulations of a 2/1 classical tearing mode in a low-beta large aspect-ratio circular tokamak. These simulations use a nonlinear 3D reduced-MHD fluid model and the JOREK code. During the initial period where the EC driven current grows and spreads throughout the magnetic island, it is not a function of the magnetic flux. However, once it has reached a steady-state, it should be a flux function. We demonstrate numerically that if sufficiently resolved toroidally, the steady-state EC driven current becomes approximately a flux function. We discuss the physics of this early period of EC evolution and its impact on the size of the magnetic island.Comment: 12 pages, 7 figure

Effect of the source charge on charged-beam interferometry

We investigate quantal perturbations of the interferometric correlations of charged bosons by the Coulomb field of an instantaneous, charged source. The source charge increases the apparent source size by weakening the correlation at non-zero relative momenta. The effect is strongest for pairs with a small total momentum and is stronger for kaons than for pions of the same momenta. The experimental data currently available are well described by this effect without invoking Pratt's exploding source model. A simple expression is proposed to account for the effect.Comment: 9 pages TEX, 3 Postscript figures available at http://www.krl.caltech.edu/preprints/MAP.htm

Automated Data Management Information System (ADMIS)

ADMIS stores and controls data and documents associated with manned space flight effort. System contains all data oriented toward a specific document; it is primary source of reports generated by the system. Each group of records is composed of one document record, one distribution record for each recipient of the document, and one summary record

Quasi-chemical Theories of Associated Liquids

It is shown how traditional development of theories of fluids based upon the concept of physical clustering can be adapted to an alternative local clustering definition. The alternative definition can preserve a detailed valence description of the interactions between a solution species and its near-neighbors, i.e., cooperativity and saturation of coordination for strong association. These clusters remain finite even for condensed phases. The simplest theory to which these developments lead is analogous to quasi-chemical theories of cooperative phenomena. The present quasi-chemical theories require additional consideration of packing issues because they don't impose lattice discretizations on the continuous problem. These quasi-chemical theories do not require pair decomposable interaction potential energy models. Since calculations may be required only for moderately sized clusters, we suggest that these quasi-chemical theories could be implemented with computational tools of current electronic structure theory. This can avoid an intermediate step of approximate force field generation.Comment: 20 pages, no figures replacement: minor typographical corrections, four references added, in press Molec. Physics 199