Quantum Monte Carlo calculations of electronic excitation energies: the case of the singlet n→π∗n \to \pi^* (CO) transition in acrolein

We report state-of-the-art quantum Monte Carlo calculations of the singlet $n \to \pi^*$ (CO) vertical excitation energy in the acrolein molecule, extending the recent study of Bouab\c{c}a {\it et al.} [J. Chem. Phys. {\bf 130}, 114107 (2009)]. We investigate the effect of using a Slater basis set instead of a Gaussian basis set, and of using state-average versus state-specific complete-active-space (CAS) wave functions, with or without reoptimization of the coefficients of the configuration state functions (CSFs) and of the orbitals in variational Monte Carlo (VMC). It is found that, with the Slater basis set used here, both state-average and state-specific CAS(6,5) wave functions give an accurate excitation energy in diffusion Monte Carlo (DMC), with or without reoptimization of the CSF and orbital coefficients in the presence of the Jastrow factor. In contrast, the CAS(2,2) wave functions require reoptimization of the CSF and orbital coefficients to give a good DMC excitation energy. Our best estimates of the vertical excitation energy are between 3.86 and 3.89 eV.Comment: 6 pages, 1 figure, 2 tables, to appear in Progress in Theoretical Chemistry and Physic

A Study of Feasibility of State Water User Fees for Financing Water Development

Water user fees imposed by a state on major water uses is a possible new alternative source of state water development funds. A fee, similar to an excise tax, might be charged for the use of the water resource per se, which in a number of states is declared to be the property of the public of the state. States generally have not employed such fees as a source of operating funds for water agencies or of development capital. Only in the area of water based recreation-fishing, coating, camping, etc.—have states extensively employed user fees. The revenues from these fees, however, are used only to defray management and operating expenses associated with these activities. The implementation of user-fee financing would result in some shifts of financing burden connected with water programs from the general taxpayers of the state to specific water users. Although this approach has not been utilized by states to a significant extent, the “user pay” principle is well established in economic theory. The theory indicated that user fees would be an economically more efficient and equitable source for financing water development than general tax revenues. In the design of fee structures for major water uses, several characteristics of fees are appropriate to consider. Five which were identified in this study are as follows: equity, economic efficiency, allocational effectiveness, administrative simplicity, and revenue generating potential. These were used to evaluate different structures for extracting fees from the user. These rate design considerations may relate only indirectly to a state system of user fees since the state fees envisioned in this study in many cases may be only an add-on or surcharge to a basic charge imposed by a local entity, such as a municipality or an irrigation district. Revenue generating potential, the last of the five characteristics listed, was of primary interest in this study. Estimates of revenue potential for four major water uses—irrigation, municipal, industrial, and recreations—were made with a formula developed in this study for this purpose. Gross estimates of potential from public supply and irrigation uses were made for several selected states, and somewhat more detailed estimates were made for the four major uses in Utah. The calculations indicated that substantial amounts of funds could be generated with only modest increases in current charges. A preliminary assessment of legal and administrative implications of implementing water user fees in the State of Utah was made in this study. The results indicated that some fee alternatives probably could be implemented by administrative action; others would require legislative approval. Constitutional issues related to some alternatives would have to be resolved by the state supreme court. New uses associated with developing Utah’s vast energy resources appear to offer a particularly promising prospect for instituting a user fee program with minimal legal complications

Quantum Monte Carlo facing the Hartree-Fock symmetry dilemma: The case of hydrogen rings

When using Hartree-Fock (HF) trial wave functions in quantum Monte Carlo calculations, one faces, in case of HF instabilities, the HF symmetry dilemma in choosing between the symmetry-adapted solution of higher HF energy and symmetry-broken solutions of lower HF energies. In this work, we have examined the HF symmetry dilemma in hydrogen rings which present singlet instabilities for sufficiently large rings. We have found that the symmetry-adapted HF wave function gives a lower energy both in variational Monte Carlo and in fixed-node diffusion Monte Carlo. This indicates that the symmetry-adapted wave function has more accurate nodes than the symmetry-broken wave functions, and thus suggests that spatial symmetry is an important criterion for selecting good trial wave functions.Comment: 6 pages, 3 figures, 2 tables, to appear in "Advances in Quantum Monte Carlo", AC

Management of Groundwater Recharge Areas in the Mouth of Weber Canyon

Proper management of surface and groundwater resources is important for their prolonged and a beneficial use. Within the Weber Delta area there has existed a continual decline in the piezometric surface of the deep confined aquifer over the last 40 years. This decline ranges from approximately 20 feet along the eastern shore of the Great Salt Lake to 50 feet along in the vicinity of Hill Air Force Base. Declines in the piezometric surface are undesirable because of the increased well installation costs, increased pumping costs, decreased aquifer storage, increased risk of salt water intrusion, and the possibility of land subsidence. Declines in the piezometric surface can be prevented or reduced by utilizing artificial groundwater recharge. The purpose of this study was to develop and operate a basin groundwater model with stochastic recharge inputs to determine the feasibility of utilizing available Weber River water for the improvement of the groundwater availability. This was accomplished by preparing auxiliary computer models which generated statistically similar river flows from which river water rights were subtracted. The feasibility of utilizing this type of recharge input was examined by comparing the economic benefit gained by reducing area wide pumping lifts through artificial recharge with the costs of the recharge operations. Institutions for implementing a recharge program were examined. Through this process a greater understanding of the geohydrologic conditions of the area was obtained. Piezometric surface contour maps, geologic profiles, calibrated values for geologic and hydrologic variables, as well as system response to change were quantified

Characterization of Aptamer-Protein Complexes by X-ray Crystallography and Alternative Approaches

Aptamers are oligonucleotide ligands, either RNA or ssDNA, selected for high-affinity binding to molecular targets, such as small organic molecules, proteins or whole microorganisms. While reports of new aptamers are numerous, characterization of their specific interaction is often restricted to the affinity of binding (KD). Over the years, crystal structures of aptamer-protein complexes have only scarcely become available. Here we describe some relevant technical issues about the process of crystallizing aptamer-protein complexes and highlight some biochemical details on the molecular basis of selected aptamer-protein interactions. In addition, alternative experimental and computational approaches are discussed to study aptamer-protein interactions.

Establishment of an AAV Reverse Infection-Based Array

Background: The development of a convenient high-throughput gene transduction approach is critical for biological screening. Adeno-associated virus (AAV) vectors are broadly used in gene therapy studies, yet their applications in in vitro high-throughput gene transduction are limited. Principal Findings: We established an AAV reverse infection (RI)-based method in which cells were transduced by quantified recombinant AAVs (rAAVs) pre-coated onto 96-well plates. The number of pre-coated rAAV particles and number of cells loaded per well, as well as the temperature stability of the rAAVs on the plates, were evaluated. As the first application of this method, six serotypes or hybrid serotypes of rAAVs (AAV1, AAV2, AAV5/5, AAV8, AAV25 m, AAV28 m) were compared for their transduction efficiencies using various cell lines, including BHK21, HEK293, BEAS-2BS, HeLaS3, Huh7, Hepa1-6, and A549. AAV2 and AAV1 displayed high transduction efficiency; thus, they were deemed to be suitable candidate vectors for the RI-based array. We next evaluated the impact of sodium butyrate (NaB) treatment on rAAV vectormediated reporter gene expression and found it was significantly enhanced, suggesting that our system reflected the biological response of target cells to specific treatments. Conclusions/Significance: Our study provides a novel method for establishing a highly efficient gene transduction arra

Achieving Education for Sustainable Development (ESD) in Early Childhood Education Through Critical Reflection in Transformative Learning

The central role of education in creating a more sustainable future has been already recognized by educators and policy-makers alike. This chapter argues that this can only be truly achieved through the efforts of teachers in implementing an “education of a different kind,” a general educational shift that seeks to encompass a converging transformation of the priorities and mindsets of education professionals. In this regard, the professional preparation of teachers, as the leading actors in shaping children’s learning processes, and their continuous professional development are vital considerations for Education for Sustainable Development (ESD) to be successfully achieved. Linking transformative learning and ESD has emerged as a distinct and useful pedagogy because they both support the process of critically examining habits of mind, then revising these habits and acting upon the revised point of view. This study aims to describe and evaluate the potential of transformative learning in innovating mainstream education toward sustainability by focusing on the role of critical reflection in a capacity building research project realized in Turkey. The data was gathered from 24 early childhood educators using a mixed-method research design involving learning diaries, a learning activities survey, and follow-up interviews. This chapter identified content, context, and application method of the in-service training as factors that have contributed to the reflective practices of the participants. In addition, presenting the implications regarding the individual differences in how learners engage in critical reflection practices, this research offers a framework for a content- and process-based approach derived from Mezirow’s conception of critical reflection

Impact of a charged neighboring particle on Förster resonance energy transfer (FRET)

Förster resonance energy transfer (FRET) is an important physical phenomenon which demands precise control over the FRET rate for its wide range of applications. Hence, enhancing the FRET rate using different techniques has been extensively studied in the literature. Research indicates that introducing additional particles to a system consisting of a donor-acceptor pair can change the behaviour of FRET in the system. One such technique is to utilize the collective oscillations of the surface electrons of a neighboring electrically-neutral metal nanoparticle (MNP). However, the perceived changes on the FRET rate between the donor and the acceptor, when the MNP carries excess electrical charges are yet unknown. In this paper, we study these changes by introducing a charged MNP, in the proximity of an excited donor and a ground state acceptor. We deploy the classical Green's tensor to express the FRET rate in the system. We consider an effective dielectric response for the MNP, which accounts for the extraneous surface charge effects. We analyze the electrical potential at the acceptor position due to the changed dipole moment of the donor molecule as a result of the electric field induced at the donor position, and obtain the FRET rate of the system. This model considers arbitrary locations and orientations of the two molecular dipole moments with regard to the position of the spherical MNP. We present the enhancement of the FRET rate, predominantly caused by both the surface plasmon excitations and the extraneous surface electrical charges carried by the neighboring MNP. We obtain the results by varying the separation distance between the molecules and the MNP, the transition frequency of the donor-acceptor pair and the size of the metallic sphere. Specifically, we demonstrate that a donor-acceptor pair placed in the vicinity of an electrically-charged Silver MNP exhibits a remarkable improvement in the FRET rate. Furthermore, the aggregate FRET enhancement is determined by other characteristics such as the location of the donor, transition frequency, separation distances and the radius of the MNP. In essence, these findings reveal an approach to realize the enhanced FRET rate in a larger span in a more controlled manner that is desirable in many FRET-based applications including spectroscopic measurements