Solvation dynamics in liquid water: III: energy fluxes and structural changes

In previous installments it has been shown how a detailed analysis of energy fluxes induced by electronic excitation of a solute can provide a quantitative understanding of the dominant molecular energy flow channels characterizing solvation—and in particular, hydration— relaxation dynamics. Here this work and power approach is complemented with a detailed characterization of the changes induced by such energy fluxes. We first examine the water solvent’s spatial and orientational distributions and the assorted energy fluxes in the various hydration shells of the solute to provide a molecular picture of the relaxation. The latter analysis is also used to address the issue of a possible “inverse snowball” effect, an ansatz concerning the time scales of the different hydration shells to reach equilibrium. We then establish a link between the instantaneous torque, exerted on the water solvent neighbors’ principal rotational axes immediately after excitation and the final energy transferred into those librational motions, which are the dominant short-time energy receptor.Postprint (author's final draft

Lessons from the Draft Horse Industry in East Texas

The purpose of the study reported here was to determine and understand the variables responsible for the revival of the draft horse industry in East Texas. The draft horse industry can provide viable employment for rural entrepreneurs. The authors suggest universities and Extension rethink their traditional roles of supporting and providing resources for rural entrepreneurs engaged in agricultural enterprises that utilize relic technologies

Neonatal alloimmune thrombocytopenia

This issue of eMedRef provides information to clinicians on the pathophysiology, diagnosis, and therapeutics of neonatal alloimmune thrombocytopenia

Translational versus rotational energy flow in water solvation dynamics

Early molecular dynamics simulations discovered an important asymmetry in the speed of water solvation dynamics for charge extinction and charge creation for an immersed solute, a feature representing a first demonstration of the breakdown of linear response theory. The molecular level mechanism of this asymmetry is examined here via a novel energy flux theoretical approach coupled to geometric probes. The results identify the effect as arising from the translational motions of the solute-hydrating water molecules rather than their rotational/librational motions, even though the latter are more rapid and dominate the energy flow.Postprint (author's final draft

Observations of GW170817 by DESGW and the DECam GW-EM Collaboration

On August 17, 2017 LIGO/Virgo detected a binary neutron star via gravitational waves. We observed 70 sq-degrees in the LIGO/Virgo spatial localization with the DECam on the 4m Blanco telescope covering 80% of the final map. Our group independently discovered an optical counterpart in NGC 4993. We searched our entire imaged region: the object in NGC 4993 was the only viable candidate. Our observations of NGC4993 show complicated morphology but simple star formation history. Our x-ray and radio observations indicate an off-axis jet as afterglow. Our high-cadence optical and infrared spectra show a source that must be described by at least two components, one of which is dominated by the r-process nucleosynthesis elements characteristic of a kilonova. Our modeling of the light curve demonstrates such a model in which 0.05 MO of material is ejected from the system. Finally, we discuss the first standard siren measurement of H0

Study Abroad and College Students of the African Diaspora: Attitudes, Access and Barriers

This qualitative study examined the attitudes, preferences, and barriers to participation experienced by African American students attempting to participate in study abroad programs. A literature review indicates that African American students are grossly underrepresented in global education opportunities when compared with their overall enrollment numbers. Study abroad has been named as a valuable (both personally and academically) enriching experience granting competitive edges in postgraduate and professional endeavors in a globalized world. Twenty participants from purposively selected universities across the United States participated in a short-answer survey of either twelve or seven questions, depending on if they participated in a study abroad program or not. The results suggest that finances, institutional factors, and individual differences are significant factors in determining if an African American student will study abroad. Future studies tracking Black students’ active intent to study abroad, as well as those that do study abroad, can provide more insight to universities as they attempt to increase this group of students’ participations.Michelle Renee’ Harris - [email protected] W. Hynes - [email protected] Renee’ Harris - MEd is the Global Programs Coordinator for all programs affiliated with the African Bioethics Consortium at the Johns Hopkins Berman Institute of Bioethics. Her primary research/career focuses are international education program management, with special focus on minority, low-income, 1st generation, and other underrepresented groups’ participation in in global education opportunities.James W. Hynes - Corresponding author. PhD. is an Associate Professor in the School of Teaching and Learning at Sam Houston State University in Huntsville, Texas. His research focus is primarily centered on two topics. The first is sustainable development in agriculture and education in developing countries located primarily in sub-Saharan Africa. The second focus supports the first - right sizing animal traction agricultural implements developed and used by U.S. Amish farmers. This adaptation allows farmers in developing countries, whose primary source of power is either human or animal, to increase their food production and quality of life without the use of combustion engines.Michelle Renee’ Harris - Sam Houston State UniversityJames W. Hynes - Sam Houston State UniversityArmstrong, G. K. (1984). Life after study abroad: A survey of undergraduate academic and career choices. The Modern Language Journal, 68(1), 1-6.Barbuto Jr., J. E., Beenen, G., & Tran, H. (2015). The role of core self-evaluation, ethnocentrism, and cultural intelligence in study abroad success. The Journal of Management Education, 13, 268-277.Brux, J. M., & Fry, B. (2010). 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Tracking energy transfer from excited to accepting modes : application to water bend vibrational relaxation

We extend, via a reformulation in terms of Poisson brackets, the method developed previously (Rey et al., J. Phys. Chem. A, 2009, 113, 8949) allowing analysis of the pathways of an excited molecule's ultrafast vibrational relaxation in terms of intramolecular and intermolecular contributions. In particular we show how to ascertain, through the computation of power and work, which portion of an initial excess molecular energy (e.g. vibrational) is transferred to various degrees of freedom (e.g. rotational, translational) of the excited molecule itself and its neighbors. The particular case of bend excess energy relaxation in pure water is treated in detail, completing the picture reported in the work cited above. It is shown explicitly, within a classical description, that almost all of the initial water bend excitation energy is transferred—either indirectly, via Fermi resonance centrifugal coupling to the bend-excited water's rotation, or directly via intermolecular coupling— to local water librations, only involving molecules in the first two hydration shells of the vibrationally excited water molecule. Finally, it is pointed out that the Poisson bracket formulation can also be applied to elucidate the microscopic character of solvation and rotational dynamics, and should prove useful in developing a quantum treatment for energy flow in condensed phases.Postprint (published version

Are there dynamical effects in enzyme catalysis? Some thoughts concerning the enzymatic chemical step

AbstractWe offer some thoughts on the much debated issue of dynamical effects in enzyme catalysis, and more specifically on their potential role in the acceleration of the chemical step. Since the term ‘dynamics’ has been used with different meanings, we find it useful to first return to the Transition State Theory rate constant, its assumptions and the choices it involves, and detail the various sources of deviations from it due to dynamics (or not). We suggest that much can be learned about the key current questions for enzyme catalysis from prior extensive studies of dynamical and other effects in the case of reactions in solution. We analyze dynamical effects both in the neighborhood of the transition state and far from it, together with the situation when quantum nuclear motion is central to the reaction, and we illustrate our discussion with various examples of enzymatic reactions