The Dynastinae (Coleoptera: Scarabaeidae) of the Cayman Islands (West Indies), with descriptions of Tomarus adoceteus, new species (Pentodontini) and Caymania nitidissima, new genus and species (Phileurini)

The five genera and eight species of dynastine scarabs occurring in the Cayman Islands in the West Indies are reviewed. Two new, endemic species are described from Little Cayman, with supporting illustrations: Tomarus adoceteus Ratcliffe and Cave (Pentodontini), new species, and Caymania nitidissima Ratcliffe and Cave (Phileurini), new genus and species

Calculation of Electronic Coupling Matrix Elements for Ground and Excited State Electron Transfer Reactions: Comparison of the Generalized Mulliken–Hush and Block Diagonalization Methods

Two independent methods are presented for the nonperturbative calculation of the electronic coupling matrix element (Hab) for electron transfer reactions using ab initio electronic structure theory. The first is based on the generalized Mulliken–Hush (GMH) model, a multistate generalization of the Mulliken Hush formalism for the electronic coupling. The second is based on the block diagonalization (BD) approach of Cederbaum, Domcke, and co-workers. Detailed quantitative comparisons of the two methods are carried out based on results for (a) several states of the system Zn2OH2+ and (b) the low-lying states of the benzene–Cl atom complex and its contact ion pair. Generally good agreement between the two methods is obtained over a range of geometries. Either method can be applied at an arbitrary nuclear geometry and, as a result, may be used to test the validity of the Condon approximation. Examples of nonmonotonic behavior of the electronic coupling as a function of nuclear coordinates are observed for Zn2OH2+. Both methods also yield a natural definition of the effective distance (rDA) between donor (D) and acceptor (A) sites, in contrast to earlier approaches which required independent estimates of rDA, generally based on molecular structure data

A model for orientation effects in electron‐transfer reactions

A method for solving the single‐particle Schrödinger equation with an oblate spheroidal potential of finite depth is presented. The wave functions are then used to calculate the matrix element T_BA which appears in theories of nonadiabatic electron transfer. The results illustrate the effects of mutual orientation and separation of the two centers on TBA. Trends in these results are discussed in terms of geometrical and nodal structure effects. Analytical expressions related to T_BA for states of spherical wells are presented and used to analyze the nodal structure effects for T_BA for the spheroidal wells

Theoretical Study of Solvent Effects on the Electronic Coupling Element in Rigidly Linked Donor-Acceptor Systems

The recently developed generalized Mulliken-Hush approach for the calculation of the electronic coupling matrix element for electron-transfer processes is applied to two rigidly linked donor-bridge-acceptor systems having dimethoxyanthracene as the donor and a dicarbomethoxycyclobutene unit as the acceptor. The dependence of the electronic coupling matrix element as a function of bridge type is examined with and without solvent molecules present. For clamp-shaped bridge structures solvent can have a dramatic effect on the electronic coupling matrix element. The behavior with variation of solvent is in good agreement with that observed experimentally for these systems

A Theoretical Investigation of Charge Transfer in Several Substituted Acridinium Ions

We present calculations for various properties of the ground and excited states of several arylamine-substituted acridinium ion systems that have been studied experimentally. Using ab initio and semiempirical quantum mechanical methods together with the generalized Mulliken−Hush (GMH) model, we examine the excitation energies, dipole moment shifts, and electronic coupling elements for the vertical charge shift (CSh) processes in these systems. We also examine solvent effects on these properties using a dielectric continuum reaction field model. The results are in generally good agreement with available experimental results and indicate that there is strong electronic coupling in these systems over a wide range of torsional angles. Nevetheless, the initial and final cationic states remain reasonably well-localized over this range, and thus TICT state formation is unlikely in these systems. Finally, a version of the GMH model based on Koopmans\u27 Theorem is developed and found to yield coupling elements generally within a factor of 2 of the many-electron GMH for a sample acridinium system, but with overestimated adiabatic and diabatic dipole moment differences

Agent based modelling : initial assessment for use on soil bioaccessibility

This report describes the testing of Agent Based Modelling implementations in three different software packages: Repast-simphony, NetLogo and Insight-maker. These software have been evaluated against their capability to simulate the exposure of people as agents moving across Arsenic contaminated soils. Two of the three tested software (Repast-simphony and NetLogo) are recommended for assessment on more complex problems. An outline work plan is presented for future work

Understanding the contribution of target repetition and target expectation to the emergence of the prevalence effect in visual search

Behavior in visual search tasks is influenced by the proportion of trials on which a target is presented (the target prevalence). Previous research has found that when target prevalence is low (2% prevalence), participants tend to miss targets, compared with higher prevalence levels (e.g., 50% prevalence). There is an ongoing debate regarding the relative contribution of target repetition and the expectation that a target will occur in the emergence of prevalence effects. In order to disentangle these two factors, we went beyond previous studies by directly manipulating participants’ expectations regarding how likely a target was to appear on a given trial. This we achieved without using cues or feedback. Our results indicated both target repetition and target expectation contribute to the emergence of the prevalence effect

Reduced Electronic Spaces for Modeling Donor/Acceptor Interactions

Diabatic states for donor (D) and acceptor (A) interactions in electron transfer (ET) processes are formulated and evaluated, along with coupling elements (HDA) and effective D/A separation distances (rDA), for reduced electronic spaces of variable size, using the generalized Mulliken Hush model (GMH), applicable to an arbitrary state space and nuclear configuration, and encompassing Robin−Day class III and as well as class II situations. Once the electronic state space is selected (a set of n ≥ 2 adiabatic states approximated by an orbital space based on an effective 1-electron (1-e) Hamiltonian), the charge-localized GMH diabatic states are obtained as the eigenstates of the dipole moment operator, with rotations to yield locally adiabatic states for sites with multiple states. The 1-e states and energies are expressed in terms of Kohn−Sham orbitals and orbital energies. Addressing questions as to whether the estimate of HDA “improves” as one increases n, and in what sense the GMH approach “converges” with n, we carry out calculations for three mixed-valence binuclear Ru complexes, from which we conclude that the 2-state (2-st) model gives the most appropriate estimate of the effective coupling, similar (to within a rms deviation of ≤15%) to coupling elements obtained by superexchange correction of HDA values based on larger spaces (n = 3−6), and thus yielding a quasi-invariant value for HDA over the range explored in the calculations (n = 2−6). An analysis of the coupling and associated D and A states shows that the 2-st coupling involves crucial mixing with intervening bridge states (D and A “tails”), while increasingly larger state spaces for the same system yield increasingly more localized D and A states (and weaker coupling), with HDA tending to approach the limit of “bare” or “through space” coupling. These results help to reconcile seemingly contradictory assertions in the recent literature regarding the proper role of multistate frameworks in the formulation of coupling for both intra- and intermolecular ET systems.The present results are compared in detail with other reported results

Gut microbiota related to Giardia duodenalis, Entamoeba spp. and Blastocystis hominis infections in humans from Côte d'Ivoire.

INTRODUCTION: Literature data provide little information about protozoa infections and gut microbiota compositional shifts in humans. This preliminary study aimed to describe the fecal bacterial community composition of people from Côte d'Ivoire harboring Giardia duodenalis, Entamoeba spp., and Blastocystis hominis, in trying to discover possible alterations in their fecal microbiota structure related to the presence of such parasites. METHODOLOGY: Twenty fecal samples were collected from people inhabiting three different localities of Côte d'Ivoire for copromicroscopic analysis and molecular identification of G. duodenalis, Entamoeba spp., and B. hominis. Temporal temperature gradient gel electrophoresis (TTGE) was used to obtain a fingerprint of the overall bacterial community; quantitative polymerase chain reaction (qPCR) was used to define the relative abundances of selected bacterial species/group, and multivariate statistical analyses were employed to correlate all data. RESULTS: Cluster analysis revealed a significant separation of TTGE profiles into four clusters (p < 0.0001), with a marked difference for G. duodenalis-positive samples in relation to the others (p = 5.4×10-6). Interestingly, qPCR data showed how G. duodenalis-positive samples were related to a dysbiotic condition that favors potentially harmful species (such as Escherichia coli), while Entamoeba spp./B. hominis-positive subjects were linked to a eubiotic condition, as shown by a significantly higher Faecalibacterium prausnitzii-Escherichia coli ratio. CONCLUSIONS: This preliminary investigation demonstrates a differential fecal microbiota structure in subjects infected with G. duodenalis or Entamoeba spp./B. hominis, paving the way for using further next-generation DNA technologies to better understand host-parasite-bacteria interactions, aimed at identifying potential indicators of microbiota changes

Rapid detection and simultaneous molecular profile characterization of Acanthamoeba infections

Diagnosis of Acanthamoeba by microscopic examination, culture, and polymerase chain reactions (PCRs) has several limitations (sensitivity, specificity, lack of detection of several strains, cost of testing for discrimination among strains). We developed a new high-resolution melting real-time PCR (HRM) to detect and characterize Acanthamoeba infections. HRM performances were evaluated with strains from the American Type Culture Collection (ATCC) and with 20 corneal scrapings. The DNA extracted from specimens were amplified, detected, and characterized in 1 run using 2 original primers diluted in a solution containing an intercalating dye. Detection and molecular characterization of Acanthamoeba infections could be achieved in less than 2.5 h with a dramatic reduction in cost of reactants (postamplification procedures and radioactive or fluorescent-labeled molecular probes were unnecessary). HRM detection limits were 0.1 cyst/μL or less (including genotypes T5 and T11), and its sensitivity and specificity were higher than other molecular tests. For the tested strains from the ATCC, the HRM drafted 4 different profiles: Type I (genotypes T2 and T4), Type II (T5 and T7), Type III (T8), and Type IV (T1, T3, T6, T9, T11, T12, and T13)