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Purpose. To carry out a retrospective analysis of changes in the state of the white Dniester crayfish population (Pontastacus eichwaldi bessarabicus Brodsky, 1967) in the Dniester estuary. To provide a description of its abundance and range in this water body. To analyze changes in the main biological characteristics of this species at the population level in the estuary. Methodology. The material for the study was collected from the catches of commerical fishing gear during the crayfish fishery in the Dniester estuary in the period from 2017 to 2021. A complete biological analysis of the obtained material was carried out in the laboratory of the Department of Aquatic Bioresources and Aquaculture of the Odessa State Ecological University (OSEU). The total length of crayfish, their weight, absolute and working fecundity of females, egg diameter, size and weight characteristics of larvae and juveniles were determined. The feeding of crayfish in ontogeny was studied. To assess the reproductive capacity of the crayfish population in the Dniester estuary, we used the coefficient of fecundity preservation Ki calculated on the basis of the obtained data. Statistical data processing was carried out using MS Excel spreadsheets. Findings. In 1950-2021, the range of the population of the Dniester white crayfish in the Dniester estuary decreased from 13 to 7‒8 thousand hectares, and its total stock -- up to 200±50 thousand individuals. At the same time, the average density of this crayfish was 17-18 ind. per hectare of the estuary. In recent years, more than 60% of the water area, in which the population of white Dniester crayfish is found in the estuary, is located within the Lower Dniester National Nature Park. In addition, the size and weight of crayfish in the estuary have decreased in recent years. For example, in the 1960s and 1970s, up to 40-45% of individuals were characterized by a length of 13.5-16.5 cm. In 2017, the modal group consisted of individuals with a length of 9-9.5 cm, and in 2019-2021 -- 9.6-10.0 cm. The maximum size of crayfish in 2019-2021 was 14.5-15.0 cm (19‒20 cm in 1960-1970s). The reproductive capacity of the population also deteriorated. Absolute and working fecundity decreased. The Ki coefficient for the population of this species in the Dniester estuary in 2017-2018 was 0.63, and in 2020-2021 it was 0.53. This indicates a progressive decrease in the abundance of its population. Originality. For the first time in the last 25‒30 years, an assessment of the current state of the Dniester white crayfish population is given. The analysis of the available data indicates the progressive degradation of the population. A decrease in the range of distribution of this species in the estuary, a decrease in its size, the share of females in the population, and indicators of their fecundity were recorded. A decrease in the coefficient of preservation of fecundity Ki indicates a depressed state of the Dniester white crayfish population in the estuary, which threatens its further degradation. In recent years, catches of white Dniester crayfish in the Dniester estuary have decreased significantly. For example, the catch per fyke net does not exceed 1.0-2.0 kg, and the share of individuals of non-commercial size (up to 10 cm) has increased significantly. Practical Value. The research results allowed: providing an ecological and biological characterization of the state of the Dniester white crayfish population in the Dniester estuary; characterizing changes in the abundance and spatial distribution of crayfish in this water body; highlighting the peculiarities of its biology; determining the strategy of restoration and rational use of the natural population of crayfish, becoming an opportunity during the development of effective methods of its artificial reproduction. [ABSTRACT FROM AUTHOR]

The analyses of morphological seed traits of Turkish hazel have been performed in the marginal part of its natural range for the purpose of familiarizing with the variability of its natural populations. In September 2020, the seeds were collected in one cultivated and seven natural populations of Turkish hazel for the purpose of research. The inter-population variability was determined based on five measured morphometric parameters and one derived ratio. Nut length ranges from 15.24 to 17.76 mm, width from 14.17 to 15.80 mm, thickness from 10.92 to 12.38, and weight from 1.23 to 1.45 g. The obtained results showed the presence of significant variability of morphological seed traits and indicated high phenotypic variability of the researched traits and genetic differentiation of Turkish hazel populations in Serbia. The Južni Kučaj population has the largest nuts, so it can be recommended as a future seed source. The Sokolovica population has the smallest nuts. The highest variability was determined in the populations of Vukan-Krilaš and Divčibare. Therefore, the selection of these two populations for seed facilities has been confirmed as right in the conducted analyses. The results of the analysis of variance showed statistically significant differences among the researched populations for all observed traits. The available gene pool of Turkish hazel is characterized by a satisfactory degree of genetic variability, representing a good starting point for the further breeding process. The studied populations must be included in continuous conservation and breeding processes, especially by forms of in situ and ex situ conservation. [ABSTRACT FROM AUTHOR]

Average and extreme temperatures will increase in the near future, but how such shifts will affect mortality in natural populations is still unclear. We used a dynamic model to predict mortality under variable temperatures on the basis of heat tolerance laboratory measurements. Theoretical lethal temperatures for 11 Drosophila species under different warming conditions were virtually indistinguishable from empirical results. For Drosophila in the field, daily mortality predicted from ambient temperature records accumulate over weeks or months, consistent with observed seasonal fluctuations and population collapse in nature. Our model quantifies temperature-induced mortality in nature, which is crucial to study the effects of global warming on natural populations, and analyses highlight that critical temperatures are unreliable predictors of mortality. [ABSTRACT FROM AUTHOR]

In this work, we investigated the nonlinear optical (NLO) properties of excess electron electride molecules of M[Cu(Ag)@(NH3)n](M = Be, Mg and Ca; n = 1–3) using density functional theory (DFT). This electride molecules consist of an alkaline‐earth (Be, Mg and Ca) together with transition metal (Cu and Ag) doped in NH3 cluster. The natural population analysis of charge and their highest occupied molecular orbital suggests that the M[Cu(Ag)@(NH3)n] compound has excess electron like alkaline‐earth metal form double cage electrides molecules, which exhibit a large static first hyperpolarizability (β0e) (electron contribution part) and one of which owns a peak value of β0e 216,938 (a.u.) for Be[Ag@(NH3)2] and vibrational harmonic first hyperpolarizability (βzzznr) (nuclear contribution part) values and the ratio of βzzznr/βzzze, namely, η values from 0.02 for Be[Ag@(NH3)] to 0.757 for Mg[Ag@(NH3)3]. The electron density contribution in different regions on βzzze values mainly come from alkaline‐earth and transition metal atoms by first hyperpolarizability density analysis, and also explains the reason why βzzze values are positive and negative. Moreover, the frequency‐dependent values β(−2ω,ω,ω) are also estimated to make a comparison with experimental measures. © 2018 Wiley Periodicals, Inc. A theoretical study on NLO properties of M[Cu(Ag)@(NH3)n](M = Be, Mg and Ca; n = 1–3) are performed based on alkaline‐earth (Be, Mg and Ca) in combine with transition metal (Cu and Ag) doped into NH3 cluster. Research fund transition metal can provide excess electron resource as like alkaline‐earth and then form double cage electron compounds which exhibit remarkable NLO response. [ABSTRACT FROM AUTHOR]

In this work, three complexes C59Co, C59Rh and C59Ir are devised by the transition metals (Co, Rh and Ir) doped into fullerenes to study the structure-property relationships of the heterofullerenes. Results show that the natural population analysis (NPA) revealed substituting one carbon atom arouse an apparent charge transfer, which can be proved by the strong electron density transfer from SOMO to LUMO. Significantly, the first hyperpolarisability (βtot) were investigated by BHandHLYP and CAM-B3LYP and got the same trend in βtot value: C59Ir > C59Rh > C59Co. Further, two-level expression was also provided to test the βtot values of C59Co, C59Rh and C59Ir. We hope our work can offer a new idea for designing high-performance NLO materials based on metal-doped fullerene. Density function theory can provide a precise calculation on the first hyperpolarisability of metal-doped fullerenes. In this work, compared to traditional fullerene, transition metal-doped fullerenes show spectacular NLO response, the three heterofullerenes: C59Co, C59Rh and C59Ir are designed to explore NLO materials. This article takes a look at initial reasons why they possess evident first hyperpolarisabilities and outlines a step to keep research on new NLO materials. [ABSTRACT FROM AUTHOR]

Graphical abstract DFT calculations for six symmetric nickel(II) complexes of bis(thiosemicarbazones) justify geometrical parameters of crystallography data, absorption electronic spectra and trend at experimental reduction potentials. Abstract This work deals with the performance of density functional theory (DFT) for evaluating one-electron reduction potentials and UV–Vis spectra of nickel complexes containing symmetric bis(thiosemicarbazones). Nine DFT calculation methods in combination with the polarisable continuum solvation model (PCM) were applied to calculate one-electron redox potentials (E calc) of nickel complexes. The best predicted results were gained by B3PW91/6-311++G(2df,2p)//B3LYP/6-31+G(d) level of theory in DMF. The results revealed that the most important effective thermodynamic factor is the solvation factor. Although the contribution of the electron attachment (EA) energy is more than ΔΔ solv G ° and ΔΔ ε geom for NiL1 , NiL2 , NiL3 , and NiL4 , ΔΔ solv G ° and ΔΔ ε geom play important roles in redox potentials. The calculated reduction potentials reproduce the tendency in experimental data. The derived error was in the region of −0.342 to −0.051 V. Reduction potentials have correlation with the energy of the frontier molecular orbitals LUMO/HOMO. According to the Natural Population Analysis (NPA), the geometries of nickel complexes remain distorted square planar, after reduction. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • P 4 S 6 structure: wB97XD and CAMB3LYP functionals show an excellent performance. • As 4 S 6 , Sb 4 S 6 , and Bi 4 S 6 structures: M06 and M06L show high accuracy. • A structural 'relaxation' from phosphorous to bismuth indicates an increase of ionic character. Abstract A systematic computational investigation of the structural, electronic and vibrational properties of the group 15 sulfides M 4 S 6 at T d symmetry was carried out. The performance of DFT and MP2 theoretical methods was assessed compared to the high-level CCSD method. The M S bond is based on the association between p valence orbitals of M and the 3p of sulfur according to the natural population analysis. Both polarizability and polarizability volume of the cage molecules increase as the size of the atoms increases from P to Bi. A structural 'relaxation' ongoing from phosphorus to bismuth showed an increase of ionic character and it might explain the chemical instability of the heavier cage compounds. For the P 4 S 6 molecule, the functionals wB97XD and CAMB3LYP yielded excellent structural data, while for the heavier molecules As 4 S 6 , Sb 4 S 6 and Bi 4 S 6 , the M06 and M06L functionals showed high accuracy. We validated eight functionals BP86, M06L, B3LYP, M06, Μ06-2Χ, CAMB3LYP, wB97XD, B2PLYP which span from conventional GGA functionals to long-range corrected hybrid ones, and MP2, CCSD ab initio methods. Experimentally, these molecules could be useful in the structural investigation of the isolated gas phase species, besides solving complex structures of liquid, crystalline or amorphous phases. [ABSTRACT FROM AUTHOR]

A gynandromorph adult of the lawn ground cricket Polionemobius mikado (Shiraki, 1913) (Orthoptera: Trigonidiidae) was collected from a natural population. It had complete male forewings and a female ovi- positor at the end of abdomen. A normal male that encountered the gynandromorph performed a courtship song and tried to transmit a spermatophore, whereas a normal female was indifferent to the gynandro- morph. The gynandromorph showed aggressive behavior toward the normal male but not against the nor- mal female. The gynandromorph raised its forewings immediately after the antenna touched the body of the normal male and female, but no sound was produced. Overall, the gynandromorph behaved as a male, but was courted by conspecific males. Thus, the sexual identity of the gynandromorph was masculine, but sexual attractiveness was feminine. [ABSTRACT FROM AUTHOR]

Plant immunity has mainly been studied under controlled conditions, limiting our knowledge regarding the regulation of immunity under natural conditions where plants grow in association with multiple microorganisms. Plant pathology theory, based on laboratory data, predicts complex biochemical plant-pathogen interactions leading to coevolution of pathogen infectivity vs. plant recognition of microbes in multiple layers over time. However, plant immunity is currently not evaluated in relation to ecological time-scales and field conditions. Here we report status of immunity in plants without visible disease symptoms in wild populations of nightshades, Solanum dulcamara and Solanum nigrum, and in agricultural fields of potato, Solanum tuberosum. We analysed presence of pathogenesis-related proteins in over 500 asymptomatic leaf samples collected in the field in June, July and August over three years. Pathogenesis-related proteins were present in only one-third of the collected samples, suggesting low activity of the immune system. We could also detect an increase in pathogenesis-related proteins later in the growing season, particularly in S. tuberosum. Our findings, based on pathogenesis-related protein markers, indicate major gaps in our knowledge regarding the status and regulation of plant immunity under field conditions. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An efficient numerical implementation of Karafiloglou's NPEPA is described. • Poly-electron probabilities are quantified for arbitrary electron-hole patterns. • Interesting resonance-type inferences can be drawn from these probabilities. Abstract We show how a simple natural orbital-based modification of Karafiloglou's poly-electron population analysis (PEPA) [generalizing conventional one-electron natural population analysis (NPA)] allows efficient numerical evaluation of Born probabilities (populations) for an unlimited variety of localized electronic excitation patterns. The computational advantages are illustrated by simple numerical applications to CH 3 NH 2 and benzene in the framework of natural bond orbital (NBO)-based "NPEPA" keyword implementation in the forthcoming NBO 7.0 program. [ABSTRACT FROM AUTHOR]

The ability to detect and understand epistasis in natural populations is important for understanding how biological traits are influenced by genetic variation. However, identification and characterization of epistasis in natural populations remains difficult due to statistical issues that arise as a result of multiple comparisons, and the fact that most genetic variants segregate at low allele frequencies. In this review, we discuss how model organisms may be used to manipulate genotypic combinations to power the detection of epistasis as well as test interactions between specific genes. Findings from a number of species indicate that statistical epistasis is pervasive between natural genetic variants. However, the properties of experimental systems that enable analysis of epistasis also constrain extrapolation of these results back into natural populations. Highlights Identification of statistical epistasis in natural populations remains challenging due to the relationship between allele frequency and statistical power. Artificial populations have been constructed in model organisms to detect statistical epistasis between two regions of the genome; however, it is difficult to use these results to understand how epistasis operates in natural populations. Studies of focal perturbations in defined genetic backgrounds suggests that natural selection can influence the types of nonadditive relationships that exist. [ABSTRACT FROM AUTHOR]

Abstract: The emergence of thiolated metal nanoclusters provides opportunities to identify significant and unprecedented phenomena because they are at quantum sizes and can be characterized with X‐ray crystallography. Recently silver nanoclusters have received extensive interest owing to their merits, such as low‐cost and rich properties. Herein, a thiolated silver nanocluster [Ag46S7(SPhMe2)24]NO3 (Ag46 for short) with a face‐centered cubic (fcc) structure was successfully synthesized and structurally resolved by X‐ray analysis. Most importantly, interstitial sulfur was found in the lattice void of Ag46 without lattice distortion or expansion, indicating that the classic theory of interstitial metal solid solutions might be not applicable at quantum size. Furthermore, unprecedented chemical bonds and unique structural features (such as asymmetrically coordinated μ4‐S) were found in Ag46 and might be related to the interstitial sulfur, which is supported by natural population analyses. [ABSTRACT FROM AUTHOR]

Pinna nobilis is an endangered species of fan mussel found along coastal Mediterranean waters requiring special attention for conservation. Populations are restricted in number, due to anthropogenic disturbances, disease, and in some areas, low rates of recruitment. To date, the difficulties associated with the identification of planktonic stages have prompted the use of benthic collectors as a proxy for quantifying larval supply, despite important information being lost regarding planktonic processes. We present evidence of spawning utilizing a qPCR assay developed for detecting genomic DNA of P. nobilis to enable specific identification of planktonic stages to augment knowledge of P. nobilis life history. In the Ebro Delta, Spain, it has been used to study what might be limiting their reproduction locally. We demonstrate the ability to differentiate DNA of P. nobilis from other bivalve mollusks and distinguish between fertilized and unfertilized eggs of P. nobilis, which may be a crucial point for understanding the low level of recruitment seen in this natural population. We also show evidence of larval presence during the expected spawning period, although abundance in positive samples were so low that they pose new questions about factors controlling the availability of planktonic stages of P. nobilis. [ABSTRACT FROM AUTHOR]

The interaction between nickel (Ni2+), copper (Cu2+), and zinc (Zn2+) ions and 1-methylimidazole has been studied by exploring the geometries of eleven crystal structures in the Cambridge Structural Database (CSD). The coordination behavior of the respective ions was further investigated by means of density functional theory (DFT) methods. The gas-phase complexes were fully optimized using B3LYP/GENECP functionals with 6-31G∗ and LANL2DZ basis sets. The Ni2+ and Cu2+ complexes show distorted tetrahedral geometries around the central ions, with Zn2+ being a perfect tetrahedron. Natural bond orbital (NBO) analysis and natural population analysis (NPA) show substantial reduction in the formal charge on the respective ions. The interaction between metal d-orbitals (donor) and ligand orbitals (acceptor) was also explored using second-order perturbation of the Fock matrix. These interactions followed the order Ni2+ > Cu2+ > Zn2+ with Zn2+ having the least interaction with the ligand orbitals. Examination of the frontier orbitals shows the stability of the complexes in the order Ni2+ > Cu2+ < Zn2+ which is consistent with the Irving–Williams series. [ABSTRACT FROM AUTHOR]

Interspecific hybridization is often seen as a major conservation issue, potentially threatening endangered species and decreasing biodiversity. In natural populations, the conservation implications of hybridization depends on both on anthropogenic factors and the evolutionary processes maintaining the hybrid zone. However, the timeline and patterns of hybridization in the hybrid zone are often not known. Therefore, species conservation becomes a concern when recent anthropogenic changes influence hybridization and not if hybridization is part of a long-term process. Here, we use sequence data from one mitochondrial gene, three nuclear introns and one nuclear exon to estimate the direction, geographic extent, frequency and possible timeline of hybridization between three rockfish species (Sebastes auriculatus, S. caurinus, S. maliger) in the Salish Sea, Washington, USA. We show that (i) introgression occurred much more frequently in the Salish Sea than on the outer coast, (ii) introgression was highly asymmetrical from S. maliger into the other two species, (iii) almost 40% of individuals in the Salish Sea were hybrids, with frequency of hybrids increasing with isolation from the coast, and (iv) all hybrids were later generation backcrosses rather than F1 hybrids. Our results suggest long-standing low-level hybridization rather than recent onset of interbreeding because of human induced environmental change, possibly facilitated by specific environmental conditions in the sub-basins of the Salish Sea, and by differences in population sizes during recolonization of the area after the last glaciation. This rockfish hybrid system, with asymmetrical introgression and the maintenance of parental species, may prove useful to study both mechanisms that maintain species boundaries and that facilitate speciation in the presence of rapid environmental change. [ABSTRACT FROM AUTHOR]

The structures, electronic properties, bonding characters and UV-Vis spectra of (-) transition-metal phthalocyanines (TMPcs) molecules have been studied with different density function theory (DFT) methods. The calculated structural parameters agree well with previous experimental or theoretical values. Natural Population Analysis (NPA) charge revealed that - hybridizations occur when TM atoms are involved in chemical bondings. The spin magnetic moments of TMPcs are mainly from the contribution of electrons. Conceptual density functional theory (CDFT) results indicate that TMPcs molecules are willing to accept further electrons. The TM-N chemical bonds show very weak covalent nature, and are consistent with bond order analyses. Time-dependent density function theory (TD-DFT) calculations were carried out to simulate the UV-Vis spectra, and corresponding electronic transfers for dominant peaks were also obtained. [ABSTRACT FROM AUTHOR]

Geometrical and electronic properties of GeV clusters containing 1-9 Ge atoms and one V atom are calculated by using density functional theory (DFT) at the B3LYP level and the LanL2DZ basis sets. The growth pattern behavior, natural population analysis, relative stability, electronic property and magnetism of these clusters are discussed in detail. The calculation results of the geometrical show that the relative stable structures of GeV clusters adopt 3D structures from to . The results of natural population analysis show that electrons transfer from the Ge atoms to the V atoms when while the electrons transfer from the V atoms to the Ge atoms when . The GeV clusters possess higher stability and the GeV, Ge3V, Ge5V, Ge7V, and Ge9V have larger HOMO-LUMO gaps. Furthermore, the VIPs of GeV clusters show a reverse trend in contrast to the AIPs. [ABSTRACT FROM AUTHOR]

Over the last decade, there has been a growing trend of European nations with fertility rates below replacement levels, top-heavy population age structures, and, in turn, widespread natural population decrease. Meanwhile, the turmoil taking place in Syria has led leaders of nations around the world to host fleeing refugees. Many in the media claim these two components are connected-that is, those nations losing population seek refugees to resolve their crises. This article empirically tests whether the natural population change in thirty-three European nations is a significant predictor of the number of refugees the nation resettles. [ABSTRACT FROM AUTHOR]

Interaction of SOx(x = 2,3) molecules on active sites of dianiline (as a model for polyaniline, denoted here as 2PANI) was studied using density functional theory at the BLYP-D/6-31+G(d) level of theory. Natural population analysis was used to find out the charge distribution as well as the net transferred charge of SOxupon adsorption on 2PANI and the result has been compared with Mulliken charge analysis to evaluate the sensing ability of 2PANI. The computed density of states point to the remarkable orbital hybridization between SOxand 2PANI during the adsorption process. As a consequence, the results of UV–VIS confirm the sensing ability of 2PANI toward SO2and SO3. Based on our results, it can be found that at proper configuration the SO2and SO3molecules can be adsorbed on 2PANI with adsorption energies (Eads) of −18.2 and −62.9 kJ/mol (BSSE), respectively. [ABSTRACT FROM AUTHOR]

The alkaloid pattern of Glaucium flavum Crantz. from four natural populations in Bulgaria were investigated and six aporphine, two protopine and one morphinane alkaloids were determined. In accordance with the particular content and composition of alkaloids and the different localities of the species three alkaloid chemotypes were suggested. The first one contains aporphines and protopines with a main alkaloid glaucine. The second chemotype contains again aporphine and protopine alkaloids but the main alkaloid is isocorydine and the third chemotype contains besides these two types of alkaloids and the morphinane alkaloid salutaridine. [ABSTRACT FROM AUTHOR]

Because of carbon-based materials have shown excellent results for the adsorption of hydrogen as an energy source, in this study, adsorption properties of 26 boron disubstituted sumanene isomers were investigated using MP2/6-311++G(d,p)//B3LYP/6-31+G(d) level of theory. The influence of sumanene modifications on its adsorption properties towards the hydrogen molecule was evaluated and zero point energy (ZPE) and basis set superposition error (BSSE) corrections were applied to calculate interaction energies (IE). Molecular electrostatic potential (MEP) surfaces were also employed to better understanding the adsorption sites and additional details about adsorption. The adsorption properties were discussed by using density of states (DOS), projected density of states (PDOS), overlap population density of states (OPDOS) and natural bond orbital (NBO) analysis. Stability and reactivity, natural population analysis (NPA), dipole moment, HOMO–LUMO gap (HLG) and bowl depth of the isomers were discussed and temperature effects on the interaction energy were evaluated. The results indicate a physisorption mechanism and insignificant perturbation of isomers after adsorption. Also, respect to position of boron atoms in frame of sumanene, interaction energy increases or decreases in comparison with pristine sumanene. The best and the worst isomers and the best and the worst classes of isomers were proposed for future experimental studies. [ABSTRACT FROM AUTHOR]

We have formed the Al(I)-containing molecule, benzophenone-aluminum, i.e., Ph 2 COAl, and studied it by conducting density functional theory calculations on both its neutral and anionic forms and by measuring the photoelectron spectrum of its anion. Our calculations identified two nearly iso-energetic anion isomers, (Ph 2 COAl) − , the vertical detachment energies (VDE) of which are in excellent agreement with our photoelectron spectrum. Natural population analysis (NPA) of Ph 2 COAl found the Al moiety to be positively charged by +0.81 e , indicating a strongly ionic bond between Al and Ph 2 CO, i.e., Ph 2 CO − Al + . [ABSTRACT FROM AUTHOR]

Charge transfer properties and adsorption mechanism of tetracene on silver are investigated based on DFT and SERS. Optimized geometries indicate distortions in hexagonal structure and deviations in co-planarity of carbon atoms due to the variations in bond angles and dihedral angles after adsorption on silver. Natural population analysis (NPA) confirms the charge transfers from silver to tetracene. Natural bond orbital (NBO) analysis illustrates the overlapping of π(C C) and π*(C C) orbitals and that of Ag valence orbitals with π(C C) of tetracene indicating charge transfers consequent to the process of adsorption. Theoretically simulated absorption spectrum has a surface plasmon resonance peak around 520 nm with major contributions arising from the charge transfers from HOMO to LUMO, HOMO-1 to LUMO and HOMO to LUMO + 2 excitations. Theoretically predicted SERS confirms the tilted orientation of tetracene on silver surface and the charge transfers reported. Chemically reactive sites were identified through Fukui functions. Localization of electron density arising from redistribution of electrostatic potential along with the reduction in bandgap of tetracene after adsorption on silver suggests its utility in the design of electro active organic semiconducting devices. Enhancement in dipole moment, polarizability and hyperpolarizability of tetracene after adsorption on silver indicates its potential in the design of novel NLO materials. [ABSTRACT FROM AUTHOR]

Growing human footprint on the environment rapidly modifies the living conditions of natural populations. This could lead to phenotypic changes through both plasticity and evolution. Therefore, distinguishing the role of evolution in the phenotypic response to global change is a major challenge. In this study, we benefited from past and recent seeds from a population of the annual self-compatible weed Adonis annua. Seeds were sampled from the same locality at an 18 years interval and close to a region where reduction of bee pollinators’ density has been reported. We used a common garden experiment to investigate evolutionary changes, between the old (1992) and the recent (2010) sample, for some reproductive traits expected to be under selection in the context of climate warming and pollinator decline. Plants of the recent sample flowered earlier, had larger flowers, but also evolved a shorter floral longevity. The capacity of plants to reproduce autonomously (autonomous selfing) was similar in the two samples. These results are consistent with adaptation of flowering phenology to climate warming and in part consistent with the evolution of increased pollinator attraction under pollinator decline. Together with other recent studies, this study provides evidence that short-term evolution is a frequent phenomenon accompanying global change. [ABSTRACT FROM AUTHOR]

We have provided a model for understanding two isoelectronic matryoshka clusters, [Sn@Cu12@Sn20]12− and [As@Ni12@As20]3−. By dividing each of the clusters in a layer-by-layer manner and allowing each layer to follow a simple electron-filling rule, we can formulate a consistent model to explain experimental and computed properties of both matryoshka clusters that cannot be adequately explained by existing models. By analysing these clusters in a way analogous to peeling an onion, we can not only have an understanding of the structure and bonding of the two matryoshka clusters under study, but also have a generalizable model to handle certain p/d-block@d-block endohedral clusters. [ABSTRACT FROM AUTHOR]

The molecular structure of cyclohexanone was calculated by the B3LYP density functional model with 6-311++G(d,p) basis set by Gaussian program. The results from natural bond orbital analysis have been analyzed in terms of the hybridization of atoms and the electronic structure of the title molecule. The formation of hydrogen bond was investigated using natural bond orbital calculation. The electron density based local reactivity descriptors such as Fukui functions were calculated. The dipole moment (μ) and polarizability (α), anisotropy polarizability (Δα) and first order hyperpolarizability (βtot) of the molecule have been reported. Thermodynamic properties of the title compound were calculated at different temperatures. [ABSTRACT FROM AUTHOR]

The interactions of metal cations (Li+, Na+, K+, Be2+, Mg2+, Ca2+) with thiophene and its derivatives have been investigated using MP2/6-311++G** and B3LYP/6-311++G** methods in the gas phase and the water solution. The following substituents are taken into considerations: F, Cl, Br, CH3, OH and C2H3, which cover electron-withdrawing and electron-donating effects. The substituent, the metal cations and the solvent effects on the cation–π interactions are investigated. The physical properties such as dipole moment, chemical potential and chemical hardness of studied complexes have been systematically explored. Natural population analysis data, the electron density and Laplacian properties have been used to evaluate the cation–π interaction. The electron density (ρ) and Laplacian (∇2ρ) properties, estimated by atoms-in-molecules calculations, indicate that the cation–π interactions possess lowρand positive ∇2ρ, which are in agreement with electrostatic character of the cation–π interactions. Charge transfer values are calculated using Mulliken charges and reveal that the electron charge transfer takes place from thiophene and its derivatives to the metal cation in the complexes under the study. To evaluate the aromaticity of the rings upon complexation, several well-established indices of aromaticity such as the nucleus-independent chemical shift and the harmonic oscillator model of aromaticity and the aromatic fluctuation index have been used. The molecular electrostatic potential is given the visual representation of the chemically active sites and comparative reactivity of atoms. Furthermore, the effects of interactions on NMR data have been used for more investigation of the analyzed complexes. [ABSTRACT FROM AUTHOR]

In this work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and natural bond orbital (NBO) analysis of 1,5-dimethoxynaphthalene. The optimized molecular structure, atomic charges, vibrational frequencies and natural bond orbital analysis of 1,5-dimethoxynaphthalene have been studied by performing DFT/B3LYP/6-31G(d,p) level of theory. The FTIR, FT-Raman spectra were recorded in the region of 4000–400 cm − 1 and 3500–50 cm − 1 respectively. The scaled wavenumbers are compared with the experimental values. The difference between the observed and scaled wavenumber values of the most fundamentals is very small. The formation of hydrogen bond was investigated in terms of the charge density by the NBO analysis. Natural Population Analysis (NPA) was used for charge determination in the title molecule. Besides, molecular electrostatic potential (MEP), frontier molecular orbitals (FMO) analysis were investigated using theoretical calculations. [ABSTRACT FROM AUTHOR]

To investigate the questions in morphological evolution, some biologists seek to carry out evolution experiments owing to the incompleteness and uncontrollability of the fossil record and natural populations. To quantitatively analyse the morphology (cell size) evolution observed from a long-term experiment with Escherichia coli, the authors present three mathematical approximations to the Wright-Fisher model of the morphological evolution. They firstly use a deterministic approximation, which fails to predict evolutionary dynamics of cell size and proves the importance of stochasticity in large populations. Then, they develop a stochastic approximation and derive an analytic expression for the anticipated waiting time to reach the stability of cell size. The results show that the calculation of this waiting time is in good agreement with the experimental data and that the selective advantage plays a prominent role in cell size evolution, with mutation rate and population size having less impact. Finally, they employ a multistep process to approximate the Wright-Fisher model of cell size evolution and acquire an analytical formula for the median waiting time until the stability of cell size. This median time supports the idea that the selective advantage is the dominant force for the morphological evolution in the long-term experiment. [ABSTRACT FROM AUTHOR]

The algorithms for constructing Natural Atomic Orbitals (NAOs) from a reduced one-particle density matrix as well as for Natural Population Analysis (NPA) are reviewed and their novel independent cross-platform open-source implementation on Java platform, a JANPA package, is presented. The package consists of three programs: two of them generate MOLDEN files from the output of popular quantum chemistry packages (PSI4, ORCA, NwChem, Gaussian, GAMESS-US, etc.), and one program performs NAO/NPA transformations taking these data as an input. The developed programs can be freely obtained at http://janpa.sourceforge.net . [ABSTRACT FROM AUTHOR]

Adsorption of deuterium on the neutral and anionic A l n λ ( n = 1–9, 13; λ = 0, −1) clusters has been investigated systematically using density functional theory. The comparisons between the Franck–Condon factor simulated spectra and the measured photoelectron spectroscopy (PES) of Cui and co-workers help to search for the ground-state structures. The results showed that D 2 molecule tends to be dissociated on aluminum clusters and forms the radial Al D bond with one aluminum atom. By studying the evolution of the binding energies, second difference energies and HOMO–LUMO gaps as a function of cluster size, we found Al 2 D 2 , Al 6 D 2 and Al 7 D 2 ̄ clusters have the stronger relative stability and enhanced chemical stability. Also, considering the larger adsorption energies of these three clusters, we surmised that Al 2 , Al 6 and Al 7 ̄ may be the better candidates for dissociative adsorption of D 2 molecule among the clusters we studied. Furthermore, the natural population analysis (NPA) and difference electron density were performed and discussed to probe into the localization of the charges and reliable charge-transfer information in Al n D 2 and Al n D 2 ̄ clusters. [ABSTRACT FROM AUTHOR]

Geometrical, electronic and magnetic properties of small AunNi- (n = 1-9) clusters have been investigated based on density functional theory (DFT) at PW91P86 level. An extensive structural search shows that the relative stable structures of AunNi- (n = 1-9) clusters adopt 2D structure for n = 1-5, 7 and 3D structure for n = 6, 8-9. And the substitution of a Ni atom for an Au atom in the Aun+1- cluster obviously changes the structure of the host cluster. Moreover, an odd–even alternation phenomenon has been found for HOMO–LUMO energy gaps, indicating that the relative stable structures of the AunNi- clusters with odd-numbered gold atoms have a higher relative stability. Finally, the natural population analysis (NPA) and the vertical detachment energies (VDE) are studied, respectively. The theoretical values of VDE are reported for the first time to our best knowledge. [ABSTRACT FROM AUTHOR]

Interactions between the NO group and 13 different substituents (BF, BH, CF, CH, CHO, CN, F, NH, NMe, NO, NO, OH, OMe) were investigated computationally for bicyclo[2.2.2]octane (BCO) and benzene substituted at 1,4 and 1,3 positions in the ring. Three methods were employed to estimate the character and strength of the substituent effect: substituent effect stabilization energy (SESE), sigma/pi electron donor acceptor index (sEDA/pEDA) and substituent active region (cSAR) parameter. For the first time the sEDA/pEDA parameters were calculated not for the ring but for the NO group. All calculations were performed at the B3LYP/6-31G(d,p) level of theory. For 1,4 derivatives, a direct comparison of slopes of linear regressions between BCO and benzene reveals a much better transmission of the substituent effect in the latter. The ratio of slopes (benzene over BCO) is always larger than 4. It follows that the resonance effects, which are absent in the BCO, dominate in this case. For 1,3 derivatives, because of much lower correlation coefficients, estimated standard deviations (ESD) were used to calculate the ratio instead of the slopes. For these systems the ratio is much closer to the unity, which indicates that only the sigma/through space effects are present and they are of similar magnitude in benzene and BCO. It follows from natural population analysis (NPA) charges that the substituent effect in the studied systems is due mainly to through-space interactions. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Highlights: [•] Experimental (X-ray, FT-IR and UV–vis spectra) methods and theoretical methods (DFT study) were investigated. [•] Nonlinear optical properties (NLO) and natural bond orbital (NBO) analysis were analyzed. [•] Mulliken population method and natural population analysis (NPA) were calculated. [Copyright &y& Elsevier]

Increasing acceptance that evolution can be 'rapid' (or 'contemporary') has generated growing interest in the consequences for ecology. The genetics and genomics of these 'eco-evolutionary dynamics' will be-to a large extent-the genetics and genomics of organismal phenotypes. In the hope of stimulating research in this area, I review empirical data from natural populations and draw the following conclusions. (1) Considerable additive genetic variance is present for most traits in most populations. (2) Trait correlations do not consistently oppose selection. (3) Adaptive differences between populations often involve dominance and epistasis. (4) Most adaptation is the result of genes of small-to-modest effect, although (5) some genes certainly have larger effects than the others. (6) Adaptation by independent lineages to similar environments is mostly driven by different alleles/genes. (7) Adaptation to new environments is mostly driven by standing genetic variation, although new mutations can be important in some instances. (8) Adaptation is driven by both structural and regulatory genetic variation, with recent studies emphasizing the latter. (9) The ecological effects of organisms, considered as extended phenotypes, are often heritable. Overall, the study of eco-evolutionary dynamics will benefit from perspectives and approaches that emphasize standing genetic variation in many genes of small-to-modest effect acting across multiple traits and that analyze overall adaptation or 'fitness'. In addition, increasing attention should be paid to dominance, epistasis and regulatory variation. [ABSTRACT FROM AUTHOR]

Preferential chlorination sites resulting from sequential substitution reactions in the representative metallacarborane [3,3′-Co(1,2-C2B9H11)2]− have been studied by combining experimental and computational methods. Similarly to aromatic substitution, the preferential chlorination sites in metallacarborane and carborane anions are of kinetic origin. There is no site preference in thermodynamic terms; however, there are sites on which the reaction takes place more rapidly. Preferential chlorination numbers have been proven experimentally by mixing the substrate with incremental ratios of N-chlorosuccinimide at 194 ± 6 °C and analyzing the resulting samples by negative MALDI-TOF-MS. Two parameters Δ y and π y have been developed which are indicators of the ease of synthesis of species with y chlorine substituents, relative to the species with y + 1 substituents, and the persistence of the y species, relative to that with y + 1, in excess of chlorinating agent. These parameters have been used to account for the rates of the reaction. They explain the largely known stability of the hexachlorinated cobaltabisdicarbollide anion along with the mono, and dichlorinated species, but strongly support the stability of the octachlorinated cobaltabisdicarbollide anion, a species never previously reported. An excellent correlation for the relative reaction rates has been found with the 2a-NPA charges on the non-chlorinated starting material. The 2a-NPA value for a bond is defined as the sum of the NPA charges of the two bonded atoms (e.g. B–H or C–H). 2a-NPA charges match the order of attack on the bonds. [ABSTRACT FROM AUTHOR]

The geometries, stabilities, and electronic properties of FSin (n = 1 ∼ 12) clusters are systematically investigated by using first-principles calculations based on the hybrid density-functional theory at the B3LYP/6-311G level. The geometries are found to undergo a structural change from two-dimensional to three-dimensional structure when the cluster size n equals 3. On the basis of the obtained lowest-energy geometries, the size dependencies of cluster properties, such as averaged binding energy, fragmentation energy, second-order energy difference, HOMO—LUMO (highest occupied molecular orbital—lowest unoccupied molecular orbital) gap and chemical hardness, are discussed. In addition, natural population analysis indicates that the F atom in the most stable FSin cluster is recorded as being negative and the charges always transfer from Si atoms to the F atom in the FSin clusters. [ABSTRACT FROM AUTHOR]

Understanding the environmental parameters that drive adaptation among populations is important in predicting how species may respond to global climatic changes and how gene pools might be managed to conserve adaptive genetic diversity. Here, we used Bayesian FST outlier tests and allele-climate association analyses to reveal two Eucalyptus EST- SSR loci as strong candidates for diversifying selection in natural populations of a southwestern Australian forest tree, Eucalyptus gomphocephala ( Myrtaceae). The Eucalyptus homolog of a CONSTANS-like gene was an FST outlier, and allelic variation showed significant latitudinal clinal associations with annual and winter solar radiation, potential evaporation, summer precipitation and aridity. A second FST outlier locus, homologous to quinone oxidoreductase, was significantly associated with measures of temperature range, high summer temperature and summer solar radiation, with important implications for predicting the effect of temperature on natural populations in the context of climate change. We complemented these data with investigations into neutral population genetic structure and diversity throughout the species range. This study provides an investigation into selection signatures at gene-homologous EST- SSRs in natural Eucalyptus populations, and contributes to our understanding of the relationship between climate and adaptive genetic variation, informing the conservation of both putatively neutral and adaptive components of genetic diversity. [ABSTRACT FROM AUTHOR]

Density functional theory calculation has been performed to calculate the redox potential and the correct ground spin state of iron complexes in acetonitrile. Widely used B3LYP functional is applied with the spin state corrected basis sets. The newly developed protocol for the set of 21 iron complexes is to optimize the structure at the level of the B3LYP/6-31G* and to calculate the single point electronic energy with the same functional and the modified basis sets s6-31G* for the iron atom and 6-31+G* for other ligand atoms. The solvation energy is considered through the polarized continuum model and the cavity creation energy is included for the accurate spin state description. Modifying the cavity size by employing the different scaling factor according to the mean absolute value of the natural population analysis charge (MA-NPA) is introduced. The molecule with the large MA-NPA requires the cavity size smaller than the less polar one. This protocol gives only 1 wrong ground spin state among the 18 iron complexes for which experimental data are known. For the open circuit voltage (OCV) calculation, our protocol performs well yielding the mean absolute error of 0.112 V for the test set. The close correlation between the calculated and the experimental OCV are obtained. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Oseltamivir (OTV) is widely used in the treatment of both influenza virus A and B infections. Additionally, OTV is an effective antiviral drug in treating the 2009 A (H1N1) influenza virus. Clinical studies concluded that OTV is readily extensively converted to the active carboxylate metabolite after oral administration. In order to investigate the metabolism mechanism of OTV, we carried out density functional theory (DFT) quantum mechanical calculations. The molecule orbital (MO) theory and natural population analysis (NPA) were also employed to help understanding the reaction mechanism. All possible reaction pathways for OTV metabolism are considered, involving hydrolysis of ester and amide. Two mechanisms were considered in this work, viz. concerted mechanism and stepwise mechanism. Our results indicate the stepwise mechanism is more favorable in both hydrolysis reactions and the rate-determining stage is the formation of the tetrahedral intermediate. In addition, the hydrolysis reactions can be assisted by substrate NH2 group and solvent water molecules. The substrate-assisted mechanism for the formation of the carboxylate metabolite is the most favorable one. [ABSTRACT FROM AUTHOR]