Synthesis and Effect of CaTiO3 formation in CaO·Al2O3 by Solid-State Reaction from CaCO3· Al2O3 and Ti

CaO⋅Al2O3/CaTiO3 material was synthesized by a solid-state reaction. The effects of CaTiO3 formed into the CaO⋅Al2O3 during the synthesized process on the microstructure and mechanical properties were studied. CaCO3 was obtained from snail shells, Al2O3, and Ti powders were employed as a raw material. A chemical system with a 1:1 M ratio between CaCO3 and Al2O3 was formed, with an addition of 10 wt% Ti metallic particles. The microstructural analysis through optical microscopy, scanning electron microscopy, and X-ray diffraction was realized. The apparent density was determined by the Archimedes method, and the mechanical behavior (hardness, fracture toughness, and transversal elastic modulus) were also determined. XRD analysis revealed the formation of calcium aluminate phases such as CaAl2O4, CaAl4O7, and CaAl12O19; in addition, the CaTiO3 phase was also identified. The in-situ formation of CaTiO3 in the ceramic material, improves the mechanical properties such as the transversal elastic modulus and fracture toughness (48 GPa and 1.32 MPa m1/2, respectively) in comparison to the reference material (55 GPa and 0.43 MPa m1/2, respectively). Changes in the microstructural morphology, bulk density, and hardness values were also observed with a positive effect in the compound material

Factors of staff turnover in textile businesses in Colombia

The Colombian textile sector, which represents 3% of the gross domestic product, has staff turnover problems. When a worker quits, an immediate replacement is needed in order to not affect productivity. Companies often recruit people without training or even experience. In this paper is analyses job turnover of businesses in the textile sector in Barranquilla (Colombia) through internal, external and contextual factors with their respective indicators. The investigation is quantitative with a correlational scope and a cross-sectional design. The methodology consisted of reliability testing (Cronbach’s alpha and McDonald’s omega) and construct validity (exploratory factor analysis) for the measurement instrument. This was followed by a descriptive analysis, with measures in relation to central tendency and dispersion for each factor indicator, concluding a confirmatory factor analysis with maximum likelihood estimates to observe causality, covariation and incidence relationships. The results established that the relevant indicators are commitment and satisfaction, sickness and company flexibility. The strongest covariance is between internal and contextual factors. Consistent with the theory, it was possible to statistically validate the theoretical model applied and a tool to measure job turnover

Pyrrolidine-based catalytic microporous polymers in sustainable C=N and C=C bond formation via iminium and enamine activation

Producción CientíficaA new set of catalytic materials having a pyrrolidine moiety confined in microporous organic polymer networks (POPs) has been attained. These catalytic polymers have been prepared by a straightforward synthesis starting from microporous polymer networks made from isatin (or a mixture of isatin and trifluoroacetophenone) and 1,3,5-triphenylbenzene. The polymers efficiently catalyzed the formation of nitrones under very mild and sustainable conditions using green solvents through an iminium ion activation mechanism. The reactions are scalable, and polymers are easily recycled. Special attention has been paid to understanding all the factors that could affect the efficiency of the confined catalysts. The electronic and conformational characteristics of the pyrrolidine moiety attached to the porous polymers, as well as other features that could affect the transport through the network, such as molecular volume and shape of reactants and products, and even hydrophilic or hydrophobic properties, have been systematically evaluated. In addition, the heterogeneous polymers are also useful in Cdouble bondC bond formation through both iminium ion and enamine activation.Gobierno de España (Agencia Estatal de Investigación) - (Projects CTQ2016-78779-R, PID2019-109403RB-C22, RTI2018-096328-B-I00, CTQ2017-89217-P and PID2020-118547GBI00)Junta de Castilla y León, Unión Europea y Fondo Europeo de Desarrollo Regional (FEDER) - (Project VA224P20)

Phenotypic plasticity of growth ring traits in Pinus hartwegii at the ends of its elevational gradient

IntroductionPhenotypic plasticity (PP) could be an important short-term mechanism to modify physiological and morphological traits in response to climate change and global warming, particularly for high-mountain tree species. The objective was to evaluate PP response of growth ring traits to temperature and precipitation in Pinus hartwegii Lindl. populations located at the ends of its elevational gradient on two volcanic mountains in central Mexico (La Malinche and Nevado de Toluca).MethodsIncrement cores collected from 274 P. hartwegii trees were used to estimate their PP through reaction norms (RN), which relate the ring width and density traits with climate variables (temperature and precipitation). We estimated the trees’ sensitivity (significant RN) to climatic variables, as well as the relative proportion of RN with positive and negative slope. We also estimated the relationship between the PP of ring width and density traits using correlation and Principal Component (PC) analyses.ResultsOver 70% of all trees showed significant RN to growing season and winter temperatures for at least one growth ring trait, with a similar proportion of significant RN at both ends of the gradient on both mountains. Ring width traits had mostly negative RN, while ring density traits tended to have positive RN. Frequency of negative RN decreased from lower to higher elevation for most traits. Average PP was higher at the lower end of the gradient, especially on LM, both for ring width and ring density traits, although high intrapopulation variation in PP was found on both mountains.DiscussionResults indicate that P. hartwegii presents spatially differentiated plastic responses in width and density components of radial growth. PP was particularly strong at the lower elevation, which has higher temperature and water stress conditions, putting these populations at risk from the continuing global warming driven by climate change

Flora y vegetación de la región semiárida de Acultzingo-Maltrata, Veracruz, México

Background and Aims: In the central area of the state of Veracruz there is a semi-arid region, located mainly in the municipalities Acultzingo and Maltrata, within the Cañón del Río Blanco National Park. This region had remained unexplored from the botanical point of view and had therefore not been recorded by botanical literature. The aim of this research is to contribute to the knowledge of flora and vegetation of this region, through a floristic analisis and a description of its plant communities.Methods: Periodic collections of plants from August 2012 to July 2014 were undertaken. Additionally, the CORU and MEXU herbaria were reviewed, as well as the Flora of Veracruz series, to obtain historical records in the study area. In order to determine the taxa shared between this semiarid region and the Tehuacán-Cuicatlán Valley, a presence-absence matrix and a table summarizing the shared taxa were elaborated.Key results: Six hundred and four voucher specimens were collected, 45 records from CORU, 280 from MEXU and 80 from the review of the Flora of Veracruz series were obtained, resulting in a total of 1009 records. These data corresponded to 87 families, 247 genera and 390 taxa. The best-represented families are Asteraceae, Fabaceae, Apocynaceae, Cactaceae, Asparagaceae, Boraginaceae, Bromeliaceae, Orchidaceae and Verbenaceae. Thirty-three species were considered as new records for the state of Veracruz and 43 have a threat status in terms of national and international laws. Three different vegetal associations conforming the xerophytic scrub are extensively described.Conclusions: There are 63 species shared between the study area and the Tehuacán-Cuicatlán valley, thereby confirming the floristic relationships between these two large semi-arid regions; hence, we propose the name “Acultzingo-Tehuacán-Cuicatlán Valley”, covering the states of Veracruz, Puebla and Oaxaca.Antecedentes y Objetivos: En la porción central del estado de Veracruz existe una región semiárida, en los municipios Acultzingo y Maltrata, que forma parte del Parque Nacional Cañón del Río Blanco. Esa zona había permanecido inexplorada desde el punto de vista botánico, por lo que no estaba registrada en la literatura contemporánea. El objetivo de esta investigación es contribuir al conocimiento de la flora y vegetación de esta región, a través de un análisis florístico y una descripción de las comunidades vegetales.Métodos: Se realizaron colectas periódicas de la flora entre agosto 2012 y julio 2014. Se revisaron los herbarios CORU y MEXU, así como la serie Flora de Veracruz para obtener los registros históricos en el área de estudio. Para determinar los taxones compartidos entre esta región semiárida y el Valle de Tehuacán-Cuicatlán, se realizó una matriz de presencia-ausencia y se elaboró un cuadro que los resume.Resultados clave: En total se colectaron 604 especímenes de herbario, se obtuvieron 45 registros de la revisión de CORU, 280 de MEXU y 80 de la revisión de la serie Flora de Veracruz, para un total de 1009 registros. Estos registros comprenden 87 familias, 248 géneros y 390 taxones; las familias mejor representadas son Asteraceae, Fabaceae, Apocynaceae, Cactaceae, Asparagaceae, Boraginaceae, Bromeliaceae, Orchidaceae y Verbenaceae. Se reportan 33 especies como nuevos registros para Veracruz y 43 especies incluidas en categorías de riesgo según normas nacionales e internacionales. Se describen tres asociaciones vegetales que integran al matorral xerófilo de esta área.Conclusiones: Existen 63 especies compartidas entre la región semiárida de Acultzingo-Maltrata y el Valle de Tehuacán-Cuicatlán, confirmándose así las relaciones florísticas entre estas dos grandes regiones, por lo que se propone se denomine “Valle de Acultzingo-Tehuacán-Cuicatlán”, abarcando los estados de Veracruz, Puebla y Oaxaca

Molecular characterization and genetic diversity of Jatropha curcas L. in Costa Rica

We estimated the genetic diversity of 50 Jatropha curcas samples from the Costa Rican germplasm bank using 18 EST-SSR, one G-SSR and nrDNA-ITS markers. We also evaluated the phylogenetic relationships among samples using nuclear ribosomal ITS markers. Non-toxicity was evaluated using G-SSRs and SCARs markers. A Neighbor-Joining (NJ) tree and a Maximum Likelihood (ML) tree were constructed using SSR markers and ITS sequences, respectively. Heterozygosity was moderate (He = 0.346), but considerable compared to worldwide values for J. curcas. The PIC (PIC = 0.274) and inbreeding coefficient (f = − 0.102) were both low. Clustering was not related to the geographical origin of accessions. International accessions clustered independently of collection sites, suggesting a lack of genetic structure, probably due to the wide distribution of this crop and ample gene flow. Molecular markers identified only one non-toxic accession (JCCR-24) from Mexico. This work is part of a countrywide effort to characterize the genetic diversity of the Jatropha curcas germplasm bank in Costa Rica.Consejo Nacional de Rectores/[736-B1-660]/CONARE/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Biología Celular y Molecular (CIBCM

Valorization of Quercus suber L. Bark as a Source of Phytochemicals with Antimicrobial Activity against Apple Tree Diseases

Cork, an anatomic adaptation of the bark of Quercus suber L. through its suberization process, finds its main application in the production of bottle stoppers. Its processing results in a large waste stream of cork fragments, granulates, and dust, which may be susceptible to valorization. The work presented here explored the use of its extracts to inhibit the growth of phytopathogenic microorganisms associated with apple tree diseases. The in vitro antimicrobial activity of cork aqueous ammonia extract was assayed against four fungi, viz. Monilinia fructigena and M. laxa (brown rot), Neofussicoccum parvum (dieback), and Phytophthora cactorum (collar and root rot), and two bacteria, viz. Erwinia amylovora and Pseudomonas syringae pv. syringae, either alone or in combination with chitosan oligomers (COS). Effective concentration values of EC90 in the 675–3450 μg·mL−1 range, depending on the fungal pathogen, were obtained in growth inhibition tests, which were substantially improved for the conjugate complexes (340–801 μg·mL−1) as a result of strong synergism with COS. Similar enhanced behavior was also observed in antibacterial activity assays, with MIC values of 375 and 750 μg·mL−1 for the conjugate complexes against P. syringae pv. syringae and E. amylovora, respectively. This in vitro inhibitory activity was substantially higher than those exhibited by azoxystrobin and fosetyl-Al, which were tested for comparison purposes, and stood out among those reported for other natural compounds in the literature. The observed antimicrobial activity may be mainly attributed to the presence of glycerin and vanillic acid, identified by gas chromatography–mass spectroscopy. In the first step towards in-field application, the COS–Q. suber bark extract conjugate complex was further tested ex situ against P. cactorum on artificially inoculated excised stems of the ‘Garnem’ almond rootstock, achieving high protection at a dose of 3750 μg·mL−1. These results suggest that cork industrial leftovers may, thus, be a promising source of bioactive compounds for integrated pest management.Publishe

Holm Oak (Quercus ilex subsp. ballota (Desf.) Samp.) Bark Aqueous Ammonia Extract for the Control of Invasive Forest Pathogens

Holm oak (Quercus ilex subsp. ballota (Desf.) Samp.) bark is a commonly used remedy to treat gastrointestinal disorders, throat and skin infections, hemorrhages, and dysentery. It has also been previously reported that its methanol extracts possess antibacterial activity, which can be related to the richness of Quercus spp. extracts in phenolic compounds, such as flavonoids and tannins. However, there is no information on the antifungal (including oomycete) properties of the bark from Q. ilex or its subspecies (ilex and ballota). In this work, we report the characterization of the aqueous ammonia extract of its bark by FTIR and GC-MS and the results of in vitro and ex situ inhibition tests against three phytopathogens. The main phytochemical components identified were inositols (19.5%), trans-squalene (13%), 4-butoxy-1-butanol (11.4%), gulopyranose (9.6%), lyxose (6.5%), 2,4-dimethyl-benzo[H]quinoline (5.1%), catechol (4.5%), and methoxyphenols (4.2%). The efficacy of the extract in controlling forest phytopathogens was tested in vitro against Fusarium circinatum (responsible for pitch canker of Pinus spp.), Cryphonectria parasitica (which causes chestnut blight), and Phytophthora cinnamomi (which causes ‘root and crown rot’ in a variety of hosts, including Castanea, conifers, Eucalyptus, Fagus, Juglans, Quercus, etc.), obtaining EC90 values of 322, 295, and 75 μg·mL−1, respectively, much lower than those attained for a commercial strobilurin fungicide (azoxystrobin). The extract was further tested ex situ against P. cinnamomi on artificially inoculated, excised stems of ‘Garnem’ almond rootstock, attaining complete protection at a dose of 782 μg·mL−1. The results suggest that holm oak bark extract may be a promising source of bioactive compounds against invasive forest pathogens, including the oomycete that is causing its decline, the so-called ‘seca’ in Spain.Publishe

The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment

The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in operation since July 2014. This paper describes the second data release from this phase, and the fourteenth from SDSS overall (making this, Data Release Fourteen or DR14). This release makes public data taken by SDSS-IV in its first two years of operation (July 2014-2016). Like all previous SDSS releases, DR14 is cumulative, including the most recent reductions and calibrations of all data taken by SDSS since the first phase began operations in 2000. New in DR14 is the first public release of data from the extended Baryon Oscillation Spectroscopic Survey (eBOSS); the first data from the second phase of the Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2), including stellar parameter estimates from an innovative data driven machine learning algorithm known as "The Cannon"; and almost twice as many data cubes from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous release (N = 2812 in total). This paper describes the location and format of the publicly available data from SDSS-IV surveys. We provide references to the important technical papers describing how these data have been taken (both targeting and observation details) and processed for scientific use. The SDSS website (www.sdss.org) has been updated for this release, and provides links to data downloads, as well as tutorials and examples of data use. SDSS-IV is planning to continue to collect astronomical data until 2020, and will be followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14 happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov 2017 (this is the "post-print" and "post-proofs" version; minor corrections only from v1, and most of errors found in proofs corrected