Theoretical investigation of the eight low-lying electronic states of the cis- and trans-nitric oxide dimers and its isomerization using multiconfigurational second-order perturbation theory (CASPT2)

In this work we have carried out ab initio electronic structure calculations, CASSCF/CASPT2 and CASSCF/MRCI-SD+Q with several Pople's and correlation-consistent Dunning's basis sets, of the planar cis- and trans-NO dimers for the lowest eight electronic (singlet and triplet) states. The geometry, frequencies, dipole moment, binding energy, and vertical excitation energies are predicted with an accuracy close to or even better than the best reported ab initio previous results for some of these properties, and in very good agreement with the available experimental data. CASPT2 optimized geometries show the existence of at least four shallow NO-dimers (i.e., two cis-(NO)2 (1A1 and 3B2) and two trans-(NO)2 (1Ag and 3Au)), although CASSCF optimization with CASPT2 pointwise calculations indicate the existence of other less stable dimers, on the excited states. Vertical excitation energies were calculated for these four dimers. For the cis-NO dimer, the ordering and the energy spacings between the excited states (i.e., 1A1, 3B2, 1B2, 2nd 1A1, 1A2, 3A2, 3B1, 2nd 3B1) are very similar to those found in a recent MRCI-SD study. The singlet cis-NO dimer (1A1) is the most stable one in almost quantitative accord with the experimental data, and in disagreement with previous density functional theory studies. A nonplanar transition state for the singlet trans ↔ cis isomerization has also been fully characterized. This leads to an almost negligible energy barrier which would originate a rapid isomerization to the most stable cis-NO dimer at low temperatures, in accord with the experimental difficulties to measure the properties of the trans-NO dimer. Not only are basis set superposition error corrections necessary to evaluate accurately the binding energies, but also to determine the NN distance of these symmetrical dimers. Some problems regarding the symmetry of the wave function were found for the symmetrical NO dimers and for the NO+NO asymptote, and several approximate solutions were proposed

Ab initio 1A' ground potential energy surface and transition state theory kinetics study of the O(1D) + N2O → 2NO, N2 +O2(a1Δg) reactions

An ab initio study of the 1A' ground potential energy surface (PES) of the O(1D) + N2O(X1+) system has been performed at the CASPT2//CASSCF (complete active space second-order perturbation theory//complete active space self-consistent field) level with Pople basis sets. The two reactions leading to 2 NO(X2) [reaction (1)] and N2(X1g+) + O2(a1∆g) [reaction (2)] products have been investigated. In both reactions a trans-approach of the attacking oxygen to the N2O moiety is found to be preferred, more markedly in reaction (1). For this reaction also a cis-path is feasible and is possibly connected with the trans -path by a transition state placed below reactants. A thorough characterization of the entrance zone has been performed to allow for subsequent kinetics calculations. Fixed angle and minimum energy paths have been constructed and transition state geometries have been refined at the CASPT2 level, thus obtaining approximate structures and frequencies for the latter. From these calculations it can be inferred that both reactions proceed without an energy barrier. Rate constant calculations in the 100-1000 K temperature range based on CASPT2 structures and using the transition state theory yield values in good agreement with experiment for the two reactions, especially when a proper scaling of the energy barriers is performed. Also, for comparative purposes quasiclassical trajectory calculations were performed on reaction (1) in the same temperature range, using a previous pseudotriatomic analytical potential energy surface, obtaining good agreement with experiment

Kernel Methods and their derivatives: Concept and perspectives for the Earth system sciences

Kernel methods are powerful machine learning techniques which implement generic non-linear functions to solve complex tasks in a simple way. They Have a solid mathematical background and exhibit excellent performance in practice. However, kernel machines are still considered black-box models as the feature mapping is not directly accessible and difficult to interpret.The aim of this work is to show that it is indeed possible to interpret the functions learned by various kernel methods is intuitive despite their complexity. Specifically, we show that derivatives of these functions have a simple mathematical formulation, are easy to compute, and can be applied to many different problems. We note that model function derivatives in kernel machines is proportional to the kernel function derivative. We provide the explicit analytic form of the first and second derivatives of the most common kernel functions with regard to the inputs as well as generic formulas to compute higher order derivatives. We use them to analyze the most used supervised and unsupervised kernel learning methods: Gaussian Processes for regression, Support Vector Machines for classification, Kernel Entropy Component Analysis for density estimation, and the Hilbert-Schmidt Independence Criterion for estimating the dependency between random variables. For all cases we expressed the derivative of the learned function as a linear combination of the kernel function derivative. Moreover we provide intuitive explanations through illustrative toy examples and show how to improve the interpretation of real applications in the context of spatiotemporal Earth system data cubes. This work reflects on the observation that function derivatives may play a crucial role in kernel methods analysis and understanding.Comment: 21 pages, 10 figures, PLOS One Journa

Adsorption and dissociation of molecular hydrogen on orthorhombic β- Mo2C and cubic δ-MoC (001) surfaces

Molybdenum carbides are increasingly used in heterogeneously catalyzed hydrogenation reactions, which imply the adsorption and dissociation of molecular hydrogen. Here a systematic density functional theory based study, including or excluding dispersion terms, concerning the interaction and stability of H2 with cubic δ-MoC(001) and orthorhombic β-Mo2C(001) surfaces is presented. In the latter case the two possible C or Mo terminations are considered. In addition, different situations for the H covered surfaces are examined. Computational results including dispersive forces predict as essentially spontaneous dissociation of H2 on β-Mo2C(001) independently of the surface termination, whereas on δ-MoC(001) molecular hydrogen dissociation implies a small but noticeable energy barrier. Furthermore, the ab initio thermodynamics formalism has been used to compare the stability of different H coverages. Finally, core level binding energies and vibrational frequencies are presented with the aim to assist the interpretation of yet unavailable data from X-ray photoelectron and infrared spectroscopies

Active Optical Sensors for Tree Stem Detection and Classification in Nurseries.

Active optical sensing (LIDAR and light curtain transmission) devices mounted on a mobile platform can correctly detect, localize, and classify trees. To conduct an evaluation and comparison of the different sensors, an optical encoder wheel was used for vehicle odometry and provided a measurement of the linear displacement of the prototype vehicle along a row of tree seedlings as a reference for each recorded sensor measurement. The field trials were conducted in a juvenile tree nursery with one-year-old grafted almond trees at Sierra Gold Nurseries, Yuba City, CA, United States. Through these tests and subsequent data processing, each sensor was individually evaluated to characterize their reliability, as well as their advantages and disadvantages for the proposed task. Test results indicated that 95.7% and 99.48% of the trees were successfully detected with the LIDAR and light curtain sensors, respectively. LIDAR correctly classified, between alive or dead tree states at a 93.75% success rate compared to 94.16% for the light curtain sensor. These results can help system designers select the most reliable sensor for the accurate detection and localization of each tree in a nursery, which might allow labor-intensive tasks, such as weeding, to be automated without damaging crops

Comparison of Mycoplasma hyopneumoniae and porcine circovirus 2 commercial vaccines efficacy when applied separate or combined under experimental conditions

Background Mycoplasma hyopneumoniae (Mhyo) and Porcine circovirus 2 (PCV-2) are two of the most significant infectious agents causing economic losses in the weaning to slaughter period. Due to their similar vaccination age, the objective of this study was to assess the efficacy of two already existing Mhyo (Hyogen®) and PCV-2 (Circovac®) vaccines when administered separately or combined (RTM) by means of Mhyo or PCV-2 experimental challenges. Results Seven groups of animals were included in the study, being three of them challenged with PCV-2, three with Mhyo and one composed of non-challenged, non-vaccinated pigs. Within each experimental challenge, non-vaccinated (NV) groups were compared with double vaccinated groups using the commercial products separated (VS) or combined (VC). Both vaccinated groups showed significant differences for most parameters measured regarding PCV-2 (serology, percentage of infected animals and viral load in tissues) and Mhyo (serology and gross lesions) when compared to NV groups. VS and VC offered similar results, being only significantly different the PCV-2 antibody values at different time points (higher in the VS group) of the study, although not at the termination day (21 days post-PCV-2 inoculation). Conclusion The present study expands the knowledge on the possibility of using two separate Mhyo and PCV-2 commercial vaccines as a RTM product, which offered equivalent virological, immunological and pathological outcomes as compared to these vaccines when used by separate.info:eu-repo/semantics/publishedVersio

Adsorption of azo-dye Orange II from aqueous solutions using a metal-organic framework material: Iron- benzenetricarboxylate

A Metal-Organic Framework (MOF), iron-benzenetricarboxylate (Fe(BTC)), has been studied for the adsorptive removal of azo-dye Orange II from aqueous solutions, where the effect of various parameters was tested and isotherm and kinetic models were suggested. The adsorption capacities of Fe(BTC) were much higher than those of an activated carbon. The experimental data can be best described by the Langmuir isotherm model (R2 > 0.997) and revealed the ability of Fe(BTC) to adsorb 435 mg of Orange II per gram of adsorbent at the optimal conditions. The kinetics of Orange II adsorption followed a pseudo-second-order kinetic model, indicating the coexistence of physisorption and chemisorption, with intra-particle diffusion being the rate controlling step. The thermodynamic study revealed that the adsorption of Orange II was feasible, spontaneous and exothermic process (-25.53 kJ·mol-1). The high recovery of the dye showed that Fe(BTC) can be employed as an effective and reusable adsorbent for the removal of Orange II from aqueous solutions and showed the economic interest of this adsorbent material for environmental purposes. © 2014 by the authors.The authors thank Autonomous Metropolitan University for its financial support to the project “Synthesis, modification and application of porous solid materials to sorption phenomena and catalysis”. Elizabeth Rojas-Garcia and Ricardo López-Medina thank CONACYT for their repatriation program fellowships. We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)Peer Reviewe

Effects of non-pharmacological interventions on inflammatory biomarker expression in patients with fibromyalgia: A systematic review

Introduction: Fibromyalgia (FM) is a prevalent disorder. However, few studies have evaluated the effect of treatment interventions on biomarker expression. The aim of this review was to explore the efficacy of non-pharmacological interventions on inflammatory biomarker expression, specifically cytokines, neuropeptides and C-reactive protein (CRP), in FM patients. Method: A literature search using PubMed, EMBASE, PsycINFO and the Cochrane library was performed from January 1990 to March 2015. Randomized controlled trials (RCTs) and non-RCTs published in English, French or Spanish were eligible. Results: Twelve articles with a total of 536 participants were included. After exercise, multidisciplinary, or dietary interventions in FM patients, interleukin (IL) expression appeared reduced, specifically serum IL-8 and IL-6 (spontaneous, lipopolysaccharide (LPS)-induced, or serum). Furthermore, the changes to insulin-like growth factor 1 (IGF-1) levels might indicate a beneficial role for fatigue in obese FM patients. In contrast, evidence of changes in neuropeptide and CRP levels seemed inconsistent. Conclusion: Despite minimal evidence, our findings indicate that exercise interventions might act as an anti-inflammatory treatment in FM patients and ameliorate inflammatory status, especially for pro-inflammatory cytokines. Additional RCTs focused on the changes to inflammatory biomarker expression after non-pharmacological interventions in FM patients are needed

Effects of mindfulness-based interventions on biomarkers in healthy and cancer populations: A systematic review

Background: Only a small number of articles have investigated the relationship between mindfulness-based interventions (MBIs) and biomarkers. The aim of this systematic review was to study the effect of MBIs on specific biomarkers (cytokines, neuropeptides and C-reactive protein (CRP)) in both healthy subjects and cancer patients. Methods: A search was conducted using PubMed, EMBASE, PsycINFO and the Cochrane library between 1980 and September 2016. Results: A total of 13 studies with 1110 participants were included. In the healthy population, MBIs had no effect on cytokines, but were found to increase the levels of the neuropeptide insulin-like growth factor 1 (IGF-1). With respect to neuropeptide Y, despite the absence of post-intervention differences, MBIs may enhance recovery from stress. With regard to CRP, MBIs could be effective in lower Body Mass Index (BMI) individuals. In cancer patients, MBIs seem to have some effect on cytokine levels, although it was not possible to determine which specific cytokines were affected. One possibility is that MBIs might aid recovery of the immune system, increasing the production of interleukin (IL)-4 and decreasing interferon gamma (IFN-¿). Conclusions: MBIs may be involved in changes from a depressive/carcinogenic profile to a more normalized one. However, given the complexity and different contexts of the immune system, and the fact that this investigation is still in its preliminary stage, additional randomized controlled trials are needed to further establish the impact of MBI programmes on biomarkers in both clinical and non-clinical populations

Subtropical cyclone formation via warm seclusion development: the importance of surface fluxes

Subtropical cyclones (STCs) are characterized by a thermal hybrid structure with tropical and extratropical features. STCs are considered a numerical modeling challenge because of their rapid intensification. A fundamental part of their strength is derived from diabatic processes associated with convection and heat fluxes from the ocean. This study evaluates the importance of surface turbulent heat fluxes during the transition of an extratropical precursor into a STC. This cyclone evolved embedded within a strong meridional flow, having a Shapiro‐Keyser structure and undergoing a warm seclusion process. To assess the importance of those heat fluxes, two Weather Research and Forecasting simulations were defined considering the presence and absence of those fluxes. Results of both simulations reveal a warm seclusion process, which weakened in absence of the heat fluxes. During the system genesis and in absence of heat fluxes, the wind and rainfall values were increased due to the remarkably intense area of frontogenesis to the northwest. Given these results and the lack of transition in the absence of heat fluxes, the frontal nature of the system was verified. Considering the heat fluxes, the obtained potential vorticity values diminished, reducing wind shear and intensifying convection in the system, which favored its transition into an STC. This study is groundbreaking in that no STC has been linked to a warm seclusion process in the Eastern North Atlantic. Additionally, simulated wind field shows an underestimation in comparison with Atmospheric Motion Vectors, used as observational data so as to give a weight to the wind analysis.This work was partially supported by research projects PCIN-2014-013-C07-04, PCIN2016-080 (UE ERA-NET Plus NEWA Project), CGL2016-78702-C2-1-R, CGL2016-78702-C2-2-R, and CGL2016-81828-REDT and the ECMWF special projects (SPESMART and SPESVALE)