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BackgroundHybrids are expected to show greater phenotypic variation than their parental species, yet how hybrid phenotype expression varies with genetic distances in closely-related parental species remains surprisingly understudied. Here we study pelage and morphometric trait variation in anthropogenic hybrids between four species of BrazilianCallithrixmarmosets, a relatively recent primate radiation. Marmoset species are distinguishable by pelage phenotype and level of morphological specialization for eating tree exudates. Here, we (1) describe qualitative phenotypic pelage differences between parental species and hybrids; (2) test whether significant quantitative differences exist between parental and hybrid morphometric phenotypes; and (3) determine which hybrid morphometic traits show heterosis, dysgenesis, trangression, or intermediacy relative to the parental trait. For morphometric traits, we investigated both cranial and post-cranial traits, particularly as most hybrid morphological studies focus on the former instead of the latter. Finally, we estimate mitogenomic distances between marmoset species from previously published data.ResultsHybrid facial and overall body pelage variation reflected coloration and patterns seen in parental species. In morphometric traits,C. jacchusandC. penicillatawere the most similar to each other, whileC. auritawas the most distinct, andC. geoffroyitrait measures fell between these other species. Most traits inC. jacchusxC. penicillatahybrids showed either heterosis or were intermediate relative to the parental trait values. We observed heterosis and dygenesis in traits ofC. penicillataxC. geoffroyihybrids. Trangressive segregation was observed in hybrids ofC. auritaand the other species. These hybrids were alsoC. aurita-like for a number of traits. Genetic distance was closest betweenC. jacchusandC. penicillataand farthest betweenC. auritaand the other species.ConclusionWe attributed significant phenotypic differences between marmoset species to differences in morphological exudivory specialization in these species. Our results suggest that intermediate hybrid traits relative to the parental trait values are more likely in crosses between species with relatively lesser genetic distance. More extreme phenotypic variation is more likely in parental species with greater genetic distance, with transgressive traits appearing in hybrids of the most genetically distant parental species. We further suggest that that less developmental disturbances can be expected in hybrids of more recently diverged parental species.

The rising of multi-resistant bacterial pathogens is currently one of the most critical threats to global health and requires urgent actions for its control and a better understanding of the origin, evolution, and spread of antibiotic resistance. It is of consensus that this must be faced under a one-health prism that includes the environment and non-human animals as possible sources and media for resistance amplification and evolution. In this regard, the resistome extension and diversity present in natural and remote environments remain largely unexplored. Moreover, little is known about the availability of antimicrobial resistance genes (ARGs) from these environments to be disseminated through horizontal transfer, potentially mediating the rise of new resistance mechanisms among clinically relevant pathogenic microorganisms. Furthermore, the impact of the anthropogenic intervention on the presence of antibiotic resistant bacteria and the underlying genes is still a matter of controversy. In this context, the Antarctic Peninsula soils are attractive remote environments to study, since their high microbial diversity, the presence of ice-covered soils sheltering ancestral microorganisms that are being exposed as cause of the global warming, and because it is one of the most transited routes between Antarctica and the rest of the world, thus permitting genetic and microbial carriage among those places. Also, it harbors both human bases and places without noticeable human intervention. In this work, we explored the culturable resistome of soils from different places of North Antarctica, including human bases and non-intervened areas. We identified bacterial isolates resistant to a wide array of antibiotics, harboring up to 10 simultaneous resistances, most of them belonging to the genus Pseudomonas. Genomic analyses of the two top resistant bacteria revealed a dominant presence of efflux pumps although an unexpectedly low abundance of known resistance genes, suggesting the presence of unidentified new mechanisms. Moreover, using 16S rRNA amplicon and metagenomic sequencing we explored the microbial diversity in the sampled soils and evaluated the presence and abundance of antimicrobial resistance genes. Proteobacteria, Bacteroidota, Acidobacteriota, and Verrucomicrobiota corresponded to the most abundant Phyla in most of the soils, while among the most abundant genera were Candidatus Udaeobacter, RB41, Polaromonas, and Ferruginibacter. A similarly high microbial diversity was observed when comparing humanized with non-intervened sites, although beta diversity analysis, as well as sequence composition analysis revealed significant clustering of non-intervened apart from humanized areas. We identified a variety of genes potentially involved in resistance to more than 15 drug classes in both short reads based analyses and ARGs detection among assembled contigs. Further, through performing hybrid assembly by combining short and long read sequence data we searched for resistance genes located inside possible mobile genetic elements and identified the source taxa. Polaromonas, Pseudomonas, Streptomyces, Variovorax, Bhurkolderia, and Gemmatimonas were the host taxa of most of the identified ARGs. Plasmid prediction among the assembled metagenomes led to the identification of a putative OXA-like beta-lactamase from Polaromonas spp. located inside a putative plasmid, which included all the key conserved residues for the activity of this kind of beta-lactamases. Taken together, this evidence indicates that resident North Antarctica soil microbial communities harbor a highly diverse natural resistome, part of which is located inside mobile genetic elements that could act disseminating these ARGs to other bacteria.

The Brazilian buffy-tufted-ear marmoset (Callithrix aurita), one of the world’s most endangered primates, is threatened by anthropogenic hybridization with exotic, invasive marmoset species. As there are few genetic data available for C. aurita, we developed a PCR-free protocol with minimal technical requirements to rapidly generate genomic data with genomic skimming and portable nanopore sequencing. With this direct DNA sequencing approach, we successfully determined the complete mitogenome of a marmoset that we initially identified as C. aurita. The obtained nanopore-assembled sequence was highly concordant with a Sanger sequenced version of the same mitogenome. Phylogenetic analyses unexpectedly revealed that our specimen was a cryptic hybrid, with a C. aurita phenotype and C. penicillata mitogenome lineage. We also used publicly available mitogenome data to determine diversity estimates for C. aurita and three other marmoset species. Mitogenomics holds great potential to address deficiencies in genomic data for endangered, non-model species such as C. aurita. However, we discuss why mitogenomic approaches should be used in conjunction with other data for marmoset species identification. Finally, we discuss the utility and implications of our results and genomic skimming/nanopore approach for conservation and evolutionary studies of C. aurita and other marmosets.

Background Callithrix marmosets are a relatively young primate radiation, whose phylogeny is not yet fully resolved. These primates are naturally para- and allopatric, but three species with highly invasive potential have been introduced into the southeastern Brazilian Atlantic Forest by the pet trade. There, these species hybridize with each other and endangered, native congeners. We aimed here to reconstruct a robust Callithrix phylogeny and divergence time estimates, and identify the biogeographic origins of autochthonous and allochthonous Callithrix mitogenome lineages. We sequenced 49 mitogenomes from four species (C. aurita, C. geoffroyi, C. jacchus, C. penicillata) and anthropogenic hybrids (C. aurita x Callithrix sp., C. penicillata x C. jacchus, Callithrix sp. x Callithrix sp., C. penicillata x C. geoffroyi) via Sanger and whole genome sequencing. We combined these data with previously published Callithrix mitogenomes to analyze five Callithrix species in total. Results We report the complete sequence and organization of the C. aurita mitogenome. Phylogenetic analyses showed that C. aurita was the first to diverge within Callithrix 3.54 million years ago (Ma), while C. jacchus and C. penicillata lineages diverged most recently 0.5 Ma as sister clades. MtDNA clades of C. aurita, C. geoffroyi, and C. penicillata show intraspecific geographic structure, but C. penicillata clades appear polyphyletic. Hybrids, which were identified by phenotype, possessed mainly C. penicillata or C. jacchus mtDNA haplotypes. The biogeographic origins of mtDNA haplotypes from hybrid and allochthonous Callithrix were broadly distributed across natural Callithrix ranges. Our phylogenetic results also evidence introgression of C. jacchus mtDNA into C. aurita. Conclusion Our robust Callithrix mitogenome phylogeny shows C. aurita lineages as basal and C. jacchus lineages among the most recent within Callithrix. We provide the first evidence that parental mtDNA lineages of anthropogenic hybrid and allochthonous marmosets are broadly distributed inside and outside of the Atlantic Forest. We also show evidence of cryptic hybridization between allochthonous Callithrix and autochthonous C. aurita. Our results encouragingly show that further development of genomic resources will allow to more clearly elucidate Callithrix evolutionary relationships and understand the dynamics of Callithrix anthropogenic introductions into the Brazilian Atlantic Forest.

Callithrix marmosets are a relatively young primate radiation, whose phylogeny is not yet fully resolved. These primates are naturally para- and allopatric, but three species with highly invasive potential have been introduced into the southeastern Brazilian Atlantic Forest by the pet trade. There, these species hybridize with each other and endangered, native congeners. We aimed here to reconstruct a robust Callithrix phylogeny and divergence time estimates, and identify the biogeographic origins of autochthonous and allochthonous Callithrix mitogenome lineages. We sequenced 49 mitogenomes from four species (C. aurita, C. geoffroyi, C. jacchus, C. penicillata) and anthropogenic hybrids (C. aurita x Callithrix sp., C. penicillata x C. jacchus, Callithrix sp. x Callithrix sp., C. penicillata x C. geoffroyi) via Sanger and whole genome sequencing. We combined these data with previously published Callithrix mitogenomes to analyze five Callithrix species in total.ResultsWe report the complete sequence and organization of the C. aurita mitogenome. Phylogenetic analyses showed that C. aurita was the first to diverge within Callithrix 3.54 million years ago (Ma), while C. jacchus and C. penicillata lineages diverged most recently 0.5 Ma as sister clades. MtDNA clades of C. aurita, C. geoffroyi, and C. penicillata show intraspecific geographic structure, but C. penicillata clades appear polyphyletic. Hybrids, which were identified by phenotype, possessed mainly C. penicillata or C. jacchus mtDNA haplotypes. The biogeographic origins of mtDNA haplotypes from hybrid and allochthonous Callithrix were broadly distributed across natural Callithrix ranges. Our phylogenetic results also evidence introgression of C. jacchus mtDNA into C. aurita.ConclusionOur robust Callithrix mitogenome phylogeny shows C. aurita lineages as basal and C. jacchus lineages among the most recent within Callithrix. We provide the first evidence that parental mtDNA lineages of anthropogenic hybrid and allochthonous marmosets are broadly distributed inside and outside of the Atlantic Forest. We also show evidence of cryptic hybridization between allochthonous Callithrix and autochthonous C. aurita. Our results encouragingly show that further development of genomic resources will allow to more clearly elucidate Callithrix evolutionary relationships and understand the dynamics of Callithrix anthropogenic introductions into the Brazilian Atlantic Forest.

In recent years, concern about the misuse of natural resources has been increasing. It is essential to know in detail the biodiversity of an ecosystem to understand and analyze the impact of human activities on nature, as well as to promote the economic growth of a country. To achieve these goals, public and private institutions are aggregating and sharing biological data around the world by means of biodiversity data portals. The main purpose of those portals is to provide a set of tools that help users and institutions catalog, analyze, and publish raw data about different species in a manner that is open and freely available to any interested party. Normally the process of choosing the best software solution is not straightforward. This paper proposes a methodology to evaluate a collection of data portals to establish a clear and consistent selection process that analyzes a collection of requirements and research purposes. The proposed approach is based on three strategies: the use of software engineering techniques to identify the desired group of features to be available in the data portal; the application of the Kano Satisfaction Model to score each requirement according to a preset weight of importance; and the use of tree-maps to visualize the requirements based on their implementation priority, to establish a portal deployment road-map. The proposed methodology is broadly applicable to portal analyses for many communities of practice.

In the last decade, Science has been faced with an enormous amount of data from a wide range of sources, such as the Internet, social media, IoT devices, and so on. Increasingly it is essential to develop methods and tools that enable the most varied forms of understanding of the data and transformation processes involved in an experiment. The veracity dimension plays an essential role in meeting these needs, and it must be incorporated into a data management process. This paper presents a proposal of an architecture model for a Data Portal that provides users the ability of assessment of the legitimacy of datasets. Legitimacy consists of the communication of decisions in the construction of computational models and the provenance of the data. We present the proposed architecture and how it can be embedded in scientific data portals.

Long-term research and environmental monitoring are essential for the improved management of ecosystems and natural resources. However, to reuse this data for new experiments, decision-making processes, and integrate these data with other long-term initiatives, scientists need more information related to data creation and its evolution, intellectual property rights, and technical information in order to evaluate the use of this data. Provenance metadata emerges as a way to evaluate the quality and reliability of data, audit processes and the data versioning, while enabling the data reuse and the reproducibility of experiments and analysis. However, most solutions for the capture and management of provenance metadata are based on specific tools, restricted scopes, and they are difficult to apply in distributed and heterogeneous environments. In this paper, we present an approach for capturing, managing, and publishing the provenance metadata generated in the environmental monitoring processes. Our computational architecture comprises three main components: (1) a data model based in PROV-DM and Dublin Core, (2) a repository of RDF Graphs, and (3) a Web API that provides services for collecting, storing, and querying provenance metadata. We demonstrate the application of our approach and show its practical usefulness by evaluating this architecture to manage provenance metadata generated during an environmental monitoring simulation. The results show that our approach is effective in collecting and storing provenance metadata and allows the query of an entire provenance of datasets and data products, thus enabling reuse, discovery, and visualization of raw data, processes, and scientists involved in its generation and evolution.

Solvent effects on the one- and two-photon absorption (1PA and 2PA) of disperse orange 3 (DO3) in dimethyl sulfoxide (DMSO) are studied using a discrete polarizable embedding (PE) response theory. The scheme comprises a quantum region containing the chromophore and an atomically granulated classical region for the solvent accounting for full interactions within and between the two regions. Either classical molecular dynamics (MD) or hybrid Car-Parrinello (CP) quantum/classical (QM/MM) molecular dynamics simulations are employed to describe the solvation of DO3 in DMSO, allowing for an analysis of the effect of the intermolecular short-range repulsion, long-range attraction, and electrostatic interactions on the conformational changes of the chromophore and also the effect of the solute-solvent polarization. PE linear response calculations are performed to verify the character, solvatochromic shift, and overlap of the two lowest energy transitions responsible for the linear absorption spectrum of DO3 in DMSO in the visible spectral region. Results of the PE linear and quadratic response calculations, performed using uncorrelated solute-solvent configurations sampled from either the classical or hybrid CP QM/MM MD simulations, are used to estimate the width of the line shape function of the two electronic lowest energy excited states, which allow a prediction of the 2PA cross-sections without the use of empirical parameters. Appropriate exchange-correlation functionals have been employed in order to describe the charge-transfer process following the electronic transitions of the chromophore in solution.

A combined and sequential Monte Carlo–quantum mechanics methodology is used to describe the electronic absorption spectrum of the fluorescein dianion in water. Different sets of 100 statistically relevant configurations composed of the solute and several solvent molecules are sampled from the Monte Carlo simulation for a posteriori quantum mechanical calculations of the spectra. In the largest case the configurations are composed of fluorescein and 90 explicit water molecules embedded in the electrostatic field of all remaining water molecules within a distance of 11.3 A. These configurations include 305 atoms and 842 valence electrons, justifying the use of a semi-empirical approach. The electronic spectrum is then calculated using the INDO/CIS method. The solvatochromic shift of fluorescein in water, compared with in isolation, is calculated using the discrete and explicit solvent models. The use of electrostatically embedded explicit water molecules, in INDO/CIS calculations, gives a good description o...

A produção florestal é uma atividade de importância fundamental para a economia brasileira. Estudos mostram que a ilegalidade na produção da madeira chega a 80% do total produzido. Esta madeira ilegal se transforma em legalizada durante a sua cadeia de suprimentos, graças às falhas nos sistemas de controle e monitoramento. Este trabalho analisa os problemas computacionais existentes no gerenciamento e no monitoramento do processo produtivo florestal na Floresta Amazônica e apresenta a modelagem de um sistema computacional, baseado em uma arquitetura orientada a serviços, que busca por meio da integração dos sistemas envolvidos o registro de informações das diversas etapas produtivas. Para isso, foi criado um modelo de informação que utiliza o padrão de metadados eFIDS, projetado para controlar transações eletrônicas na indústria florestal e uma base de dados centralizada, onde as informações deste processo são registradas e relacionadas, possibilitando a manutenção da rastreabilidade dos produtos e insumos florestais durante todo seu ciclo de vida, garantindo a identificação da origem florestal destes produtos para as empresas e consumidores finais. The Forest production is an activity with fundamental importance for the Brazilian economy. Studies show that the illegality in timber production is around 80% of total productive. This illegal wood becomes legalized in your supply chain due the failures in control and monitoring systems. This paper analyzes a computational problems existing in managing and monitoring productive process in the Amazon Forest and presents the modeling of a computational system, based on a service-oriented architecture, which seeks through the involved systems integration the recording of information about the various productive stages. For this was created an information model that uses the eFIDS metadata standard, designed to handle electronic transactions in the forestry industry, and a centralized database, where the process information are recorded and linked, enabling the maintenance of product and raw material traceability throughout its lifecycle, ensuring identification of the forest products origin for businesses and consumers.

Usability evaluation is a group of systematic activities that should be performed by software developers in order to identify usability problems. A widely used strategy to evaluate usability is known as User Observation and aims to analyze whether the interaction capability provided by the software is appropriated or not. Techniques, such as, Verbalization is widely used to support the evaluations based on observations due to the reason that it provides data about the quality of user interaction. In order to automate the usability evaluation test and to minimize the evaluation time, we developed a tool named ErgoSV, which is based on the verbalization technique and is capable of automatically recognize words defined in a keyword list. ErgoSV also collects, analyzes and provides relevant information about the usability test, such as: a list of pronounced words, pronounced words counter, interfaces (set of screens / video) spoken at the moment of the pronunciation and the exact time moment of pronunciation. Some usability evaluations were conducted with applications from diverse domains and showed the effectiveness of utilizing keywords to perform usability evaluation based on verbalization technique.

In this Letter, we explored the use of polarized two-photon absorption (2PA) spectroscopy, which brings additional information when compared to methods that do not use polarization control, to investigate the electronic and molecular structure of two chromophores (FD43 and FD48) based on phenylacetylene moieties. The results were analyzed using quantum chemical calculations of the two-photon transition strengths for circularly and linearly polarized light, provided by the response function formalism. On the basis of these data, it was possible to distinguish and identify the excited electronic states responsible for the lowest-energy 2PA-allowed band in both chromophores. By modeling the 2PA circular-linear dichroism, within the sum-over-essential states approach, we obtained the relative orientation between the dipole moments that are associated with the molecular structure of the chromophores in solution. This result allowed to correlate the V-shape structure of the FD48 chromophore and the quantum-interference-modulated 2PA strength.

This paper reports on the static and dynamic first-order hyperpolarizabilities of a class of push-pull octupolar triarylamine derivatives dissolved in toluene. We have combined hyper-Rayleigh scattering experiment and the coupled perturbed Hartree-Fock method implemented at the Density Functional Theory (DFT) level of theory to determine the static and dynamic (at 1064 nm) first-order hyperpolarizability (βHRS) of nine triarylamine derivatives with distinct electron-withdrawing groups. In four of these derivatives, an azoaromatic unit is inserted and a pronounceable increase of the first-order hyperpolarizability is reported. Based on the theoretical results, the dipolar/octupolar character of the derivatives is determined. By using a polarizable continuum model in combination with the DFT calculations, it was found that although solvated in an aprotic and low dielectric constant solvent, due to solvent-induced polarization and the frequency dispersion effect, the environment substantially affects the first-order hyperpolarizability of all derivatives investigated. This statement is supported due to the solvent effects to be essential for the better agreement between theoretical results and experimental data concerning the dynamic first-order hyperpolarizability of the derivatives. The first-order hyperpolarizability of the derivatives was also modeled using the two- and three-level models, where the relationship between static and dynamic first hyperpolarizabilities is given by a frequency dispersion model. Using this approach, it was verified that the dynamic first hyperpolarizability of the derivatives is satisfactorily reproduced by the two-level model and that, in the case of the derivatives with an azoaromatic unit, the use of a damped few-level model is essential for, considering also the molecular size of such derivatives, a good quantitative agreement between theoretical results and experimental data to be observed.

The digitization and integration of biodiversity data are essential for supporting environmental conservation and sustainable use of natural resources. Nowadays an increasing amount of data are made available by regional, national and global initiatives, but the efficient use of data still a challenge. New techniques are needed to enable efficient manage and the use of these various types of biotic and abiotic data to generate useful knowledge for decision-making processes. We present a work in progress research that proposes a computational framework to manage biodiversity data and to enable an efficient information retrieval process.

Transparency initiatives are increasingly present at all levels of government, making volume and variety of data grow as governmental institutions wish to make their administration more open. In this context, transparency portals appear as large silos of documents with heterogeneous and often unstructured data, in which the information provided is mainly through PDF, HTML, Excel spreadsheets or other print-like format. Although they allow comfortable reading to humans, these documents fail to provide a deep, integrated and multidimensional data analysis, which would allow citizens the effective use of transparency. We hence present a work in progress to structure this information and to allocate them into repositories that comply with Open Government Data principles to provide citizens with the power of machine analysis, indiscriminate and independent technology data access. We describe a collaborative framework that engages users in capturing and transforming unstructured information into machine-readable datasets.

This article reports on a comprehensive study of the two-photon absorption (2PA) properties of six novel push-pull octupolar triarylamine compounds as a function of the nature of the electron-withdrawing groups. These compounds present an octupolar structure consisting of a triarylamine core bearing two 3,3′-bis(trifluoromethyl)phenyl arms and a third group with varying electron-withdrawing strength (H < CN < CHO < NO2 < Cyet < Vin). The 2PA cross-sections, measured by using the femtosecond open-aperture Z-scan technique, showed significant enhancement from 45 up to 125 GM for the lowest energy band and from 95 up to 270 GM for the highest energy band. The results were elucidated based on the large changes in the transition and permanent dipole moments and in terms of (i) EWG strength, (ii) degree of donor-acceptor charge transfer and (iii) electronic coupling between the arms. The 2PA results were eventually supported and confronted with theoretical DFT calculations of the two-photon transition oscillator strengths.

Dipolar aggregation is in many cases detrimental for the functioning of optical materials. In this study we investigate self-aggregation and optical absorption of stilbazolium merocyanine (SM) in chloroform solution by performing classical Molecular Dynamics (MD) simulations under ambient conditions. The reversal solvatochromic shift, the large bathochromic shift, and the structured absorption band presented by SM in chloroform solution are all aspects of its optical absorption behavior for which the existence of self-aggregation is yet not completely understood. Moreover, the spectroscopic properties of SM oligomers and their occurrence in solvent of low polarity remain a relevant topic that deserves to be investigated. Our analysis of the aggregation behavior of SM in chloroform verified that the majority of the chromophores are involved in the formation of oligomers in solution, where the whole dimer and part of the trimer populations present a stable π-stacking structure. The optical properties of the monomers and oligomers in solution were evaluated by means of a discrete polarizable embedding quantum mechanical/molecular mechanical (PE-QM/MM) response scheme where the quantum part is described at the level of density functional theory. The visible absorption spectrum of SM in chloroform is simulated using time average values obtained for the monomeric and oligomeric forms of SM from the PE-QM/MM calculations performed on uncorrelated configurations extracted from the classical MD simulations. This study shows that the self-aggregation of SM in chloroform may exist, but it is not essential for reproducing the reversal solvatochromic shift in chloroform and that the process does not contribute to enhance the bathochromic shift nor explain the structure observed in its absorption band. Moreover, it is verified that since the electronic transitions of the monomer and oligomers are close together, changes in the interplane separation between the monomeric units of the stacked oligomers substantially affect the spectral resolution of their contribution to the optical absorption spectrum.

The advent of organocatalysis brought the prospect of a complementary mode of catalysis, with the potential for savings in cost, time and energy. 1 In this work p-sulfonic acid calix[4]arene (CX4SO3H) was employed as a organocatalyst to promote a threecomponent Povarov reaction, for the preparation of julolidines. 2 Julolidines and derivatives are endowed with interesting scientific and industrial applications. 3

In this report we investigate the two-photon absorption circular-linear dichroism (2PA-CLD) of two chiral molecules based on phenylacetylene moieties employing the Z-scan technique with polarization control

International audience; This Article reports a combined experimental and theoretical analysis on the one and two-photon absorption properties of a novel class of organic molecules with a π-conjugated backbone based on phenylacetylene (JCM874, FD43, and FD48) and azoaromatic (YB3p25) moieties. Linear optical properties show that the phenylacetylene-based compounds exhibit strong molar absorptivity in the UV and high fluorescence quantum yield with lifetimes of approximately 2.0 ns, while the azoaromatic-compound has a strong absorption in the visible region with very low fluorescence quantum yield. The two-photon absorption was investigated employing nonlinear optical techniques and quantum chemical calculations based on the response functions formalism within the density functional theory framework. The experimental data revealed well-defined 2PA spectra with reasonable cross-section values in the visible and IR. Along the nonlinear spectra we observed two 2PA allowed bands, as well as the resonance enhancement effect due to the presence of one intermediate one-photon allowed state. Quantum chemical calculations revealed that the 2PA allowed bands correspond to transitions to states that are also one-photon allowed, indicating the relaxation of the electric-dipole selection rules. Moreover, using the theoretical results, we were able to interpret the experimental trends of the 2PA spectra. Finally, using a few-energy-level diagram, within the sum-over-essential states approach, we observed strong qualitative and quantitative correlation between experimental and theoretical results.

We report the partitioning of the interaction-induced static electronic dipole (hyper)polarizabilities for linear hydrogen cyanide complexes into contributions arising from various interaction energy terms. We analyzed the nonadditivities of the studied properties and used these data to predict the electric properties of an infinite chain. The interaction-induced static electric dipole properties and their nonadditivities were analyzed using an approach based on numerical differentiation of the interaction energy components estimated in an external electric field. These were obtained using the hybrid variational-perturbational interaction energy decomposition scheme, augmented with coupled-cluster calculations, with singles, doubles, and noniterative triples. Our results indicate that the interaction-induced dipole moments and polarizabilities are primarily electrostatic in nature; however, the composition of the interaction hyperpolarizabilities is much more complex. The overlap effects substantially quench the contributions due to electrostatic interactions, and therefore, the major components are due to the induction and exchange-induction terms, as well as the intramolecular electron-correlation corrections. A particularly intriguing observation is that the interaction first hyperpolarizability in the studied systems not only is much larger than the corresponding sum of monomer properties, but also has the opposite sign. We show that this effect can be viewed as a direct consequence of hydrogen-bonding interactions that lead to a decrease of the hyperpolarizability of the proton acceptor and an increase of the hyperpolarizability of the proton donor. In the case of the first hyperpolarizability, we also observed the largest nonadditivity of interaction properties (nearly 17%) which further enhances the effects of pairwise interactions.

The wood production is an activity of fundamental importance for Brazilian economy. Studies show that the illegality in wood production is around 80% of the total production. This illegal wood becomes legalized in its supply chain due to the failures in controlling and monitoring systems. This paper analyzes some computational problems existing in managing and monitoring the production process in Amazon Forest and identifies new requirements to create a traceability system more efficient and appropriate to the region's characteristics.

In the work reported here we were able to control the photobleaching of poly[2-methoxy-5-(2′-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV), excited by two-photon absorption, using femtosecond pulse shaping. By applying a cosine-like spectral phase mask, we observe a reduction of three times in the photobleaching rate, while the fluorescence intensity decreases by 20%, in comparison to the values obtained with a Fourier-transform-limited pulse. These results demonstrate an interesting trade-off between photobleaching rate and nonlinear fluorescence intensity. The possible mechanism behind this process is discussed in terms of the pulse spectral profile and the absorbance band of MEH-PPV. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

The two-photon excited fluorescence of MEH-PPV was measured using femtosecond laser pulses. We carried out intensity and fluorescence spectrum measurements as a function of the ultrashort pulse shape.

We present results on the control of two-photon excited fluorescence with femtosecond pulses in perylene derivatives. The pulses were chirped and optimized via spectral shaping in a closed-loop evolutionary algorithm.

We investigate the three-photon absorption spectra of four platinum acetylides complexes employing femtosecond pulses. We observed strong three-photon absorption cross-section in the near-infrared region (from 850 nm to 1200 nm). The three-photon absorption (3PA) spectra present resonance enhancement effect as two photons of the excitation wavelength approach the lower two-photon allowed states of the molecules as well as a 3PA allowed band around 1180 nm. The 3PA cross-section spectra were interpreted using the sum-over-essential-states approach, considering a three-energy-level diagram.