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Number of results: 12
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Abstract

If the most parsimonious behavioral model between an observed behavior, Y, and some factors, X, can be defined as f(Y|X1, X2), then fx1 will measure the impact in behavior of a change in factor X1. Additionally, if fx1x2 ≠ 0, then the impact in behavior of a change in factor X1 is qualified, or moderated by X2. If this is the case, X2 is said to be a moderating variable and fx1x2 is said to be the moderating effect. When Y is modeled via a logistic regression, the moderation effect will exist regardless of whether the index function of the logit specification includes a moderation term or not. Thus, including a moderation terms in the index function will help the researcher more precisely qualify the moderation effect between X1 and X2. The question that naturally arises is whether the researcher must include the moderation term or not. In this document, we provide the conditions in which moderation terms will naturally arise in a logistic regression and introduce some modeling guidelines. We do so by introducing a general framework that nests models with no moderation terms in three scenarios for the independent variables, commonly found in applied research.

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Authors and Affiliations

Alfredo A. Romero
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Abstract

Prior any satellite technology developments, the geodetic networks of a country were realized from a topocentric datum, and hence the respective cartography was performed. With availability of Global Navigation Satellite Systems-GNSS, cartography needs to be updated and referenced to a geocentric datum to be compatible with this technology. Cartography in Ecuador has been performed using the PSAD56 (Provisional South American Datum 1956) systems, nevertheless it’s necessary to have inside the system SIRGAS (SIstema de Referencia Geocéntrico para las AmericaS). This transformation between PSAD56 to SIRGAS use seven transformation parameters calculated with the method Helmert. These parameters, in case of Ecuador are compatible for scales of 1:25 000 or less, that does not satisfy the requirements on applications for major scales. In this study, the technique of neural networks is demonstrated as an alternative for improving the processing of UTM planes coordinates E, N (East, North) from PSAD56 to SIRGAS. Therefore, from the coordinates E, N, of the two systems, four transformation parameters were calculated (two of translation, one of rotation, and one scale difference) using the technique bidimensional transformation. Additionally, the same coordinates were used to training Multilayer Artificial Neural Network -MANN, in which the inputs are the coordinates E, N in PSAD56 and output are the coordinates E, N in SIRGAS. Both the two-dimensional transformation and ANN were used as control points to determine the differences between the mentioned methods. The results imply that, the coordinates transformation obtained with the artificial neural network multilayer trained have been improving the results that the bidimensional transformation, and compatible to scales 1:5000.
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Authors and Affiliations

Alfonso Tierra
Ricardo Romero
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Abstract

Production development has for decades concentrated on incremental improvements by exploiting existing manufacturing knowledge to improve existing production systems or adapt them for new product developments. Building up an “ambidextrous innovation” ability, and more specifically in increasing focus on explorative production innovation, is important to balance production development efforts and obtain sustainable development of production. This paper aims to provide a conceptual framework for “ambidextrous production innovation” that conceptualizes and highlights phenomenon characteristics from exploitative and explorative perspectives. The conceptual framework describes “production innovation” as the process of either increasing or developing a new production capability, enabling opportunities for new product designs. This process can be either “product-driven” or “production-driven” depending on the primary objective of the development.
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Authors and Affiliations

Lisa Larsson
1
David Romero
2

  1. Department of Business Administration, Technology and Social Sciences, Luleå University of Technology, Sweden
  2. Departments of Industrial Engineering and Mechatronics, School of Engineering and Sciences, Tecnológico de Monterrey, Mexico
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Abstract

Nothofagaceae fossil leaves and an associated palynoflora from Late Cretaceous sediments of Vega Island, eastern Antarctic Peninsula, are presented. The leaves are described as Nothofagus sp. 1 and Morphotype LDB 1, and come from the Snow Hill Island (late Campanian-early Maastrichtian) and the López de Bertodano (late Maastrichtian) formations, respectively. The palynoflora obtained from levels immediately above and below the Nothofagus sp. 1 and in the same horizon as the Morphotype LDB 1, included terrestrial and marine elements. In the palynoflora associated with Nothofagus sp. 1, conifers are dominant and pollen grains with Nothofagus affinity are represented by four species: Nothofagidites kaitangataensis (Te Punga) Romero 1973 and Nothofagidites senectus Dettmann and Playford 1968, which belong to the ancestral pollen type, as well as Nothofagidites dorotensis Romero 1973 and Nothofagidites sp. of the brassii-type. Cryptogamic spores, marine dinoflagellate cysts and algae, among others, are part of the assemblage. The palynoflora associated with the Morphotype LDB 1 also contains abundant conifer and angiosperm pollen grains with N. dorotensis as the only Nothofagus species recorded. Marine dinoflagellate cysts are scarce while fungi and phytodebris are common elements. The joint presence of marine and non-marine palynomorphs supports a probable nearshore environment at time of deposition for both units. Pollen and spore evidence suggests a mixed conifer and angiosperm forest, with Podocarpaceae and Nothofagus as the main components, and ferns, lycopods, and mosses in the understory. This forest developed under temperate and moist conditions during the middle Campanian-Maastrichtian.

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Authors and Affiliations

Edgardo Romero
Cecilia R. Amenábar
María C. Zamaloa
Andrea Concheyro
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Abstract

In this paper an alternative procedure to vibro-acoustics study of beam-type structures is presented. With this procedure, it is possible to determine the resonant modes, the bending wave propagation velocity through the study of the radiated acoustic field and their temporal evolution in the frequency range selected. As regards the purely experimental aspect, it is worth noting that the exciter device is an actuator similar to is the one employed in distributed modes loudspeakers; the test signal used is a pseudo random sequence, in particular, an MLS (Maximum Length Sequence), facilitates post processing. The study case was applied to two beam-type structures made of a sandstone material called Bateig. The experimental results of the modal response and the bending propagation velocity are compared with well-established analytical solution: Euler-Bernoulli and Timoshenko models, and numerical models: Finite Element Method – FEM, showing a good agreement.
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Authors and Affiliations

Jeniffer Torres-Romero
William Cardenas
Jesus Carbajo
Segovia Eulogio Enrique G.
Ramis-Soriano Jaime
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Abstract

In this work we present the design and the manufacturing processes, as well as the acoustics standardization tests, of an acoustic barrier formed by a set of multi-phenomena cylindrical scatterers. Periodic arrangements of acoustic scatterers embedded in a fluid medium with different physical properties are usually called Sonic Crystals. The multiple scattering of waves inside these structures leads to attenuation bands related to the periodicity of the structure by means of Bragg scattering. In order to design the acoustic barrier, two strategies have been used: First, the arrangement of scatterers is based on fractal geometries to maximize the Bragg scattering; second, multi-phenomena scatterers with several noise control mechanisms, as resonances or absorption, are designed and used to construct the periodic array. The acoustic barrier reported in this work provides a high technological solution in the field of noise control.

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Authors and Affiliations

Sergio Castiñeira-Ibáñez
Constanza Rubio
Vicent Romero-García
Juan Vicente Sánchez-Pérez
Luís Miguel García-Raffi
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Abstract

The aim of this work was to evaluate the relative gene expression levels of the cytokines IL- 1B, IL-8, IL-12, IFN-γ, IL-4, IL-10 and TGF-β in somatic milk cells of French Alpine breed, anestrous goats that were experimentally infected in the left mammary gland with Staphylococcus chromogenes during the lactation peak. Milk samples were obtained from both glands for 21 consecutive days post infection. Total RNA was extracted, and real-time PCR was conducted using primers specific to each cytokine. The relative RNA expression of the evaluated cytokines was determined by the comparative method 2-ΔΔCT, using milk from the right gland of the goats as a reference (control) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) as an endogenous control. According to the Wilcoxon test results, IL-1B and IL-12 expression levels showed significant differences compared to those in the control group (p<0.05) from 24 hours post infection until the end of lactation; on day three, IL1β, IL8, IL12 and TGF-β had a statistically significant change in expression with respect to those in the control group (p<0.05); closer to the end of the lactation period, there is no overexpression of the anti-inflammatory interleukins (IL-4 and TGF-β) which may reflect the effort of the host immune system to eradicate the microorganism from the mammary gland.

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Authors and Affiliations

R.A. Ruiz-Romero
D. Martínez-Gómez
R.A. Cervantes-Olivares
E. Díaz-Aparicio
A.E. Ducoing-Watty
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Abstract

The Bulletin of the Polish Academy of Sciences: Technical Sciences (Bull.Pol. Ac.: Tech.) is published bimonthly by the Division IV Engineering Sciences of the Polish Academy of Sciences, since the beginning of the existence of the PAS in 1952. The journal is peer‐reviewed and is published both in printed and electronic form. It is established for the publication of original high quality papers from multidisciplinary Engineering sciences with the following topics preferred: Artificial and Computational Intelligence, Biomedical Engineering and Biotechnology, Civil Engineering, Control, Informatics and Robotics, Electronics, Telecommunication and Optoelectronics, Mechanical and Aeronautical Engineering, Thermodynamics, Material Science and Nanotechnology, Power Systems and Power Electronics.

Journal Metrics: JCR Impact Factor 2018: 1.361, 5 Year Impact Factor: 1.323, SCImago Journal Rank (SJR) 2017: 0.319, Source Normalized Impact per Paper (SNIP) 2017: 1.005, CiteScore 2017: 1.27, The Polish Ministry of Science and Higher Education 2017: 25 points.

Abbreviations/Acronym: Journal citation: Bull. Pol. Ac.: Tech., ISO: Bull. Pol. Acad. Sci.-Tech. Sci., JCR Abbrev: B POL ACAD SCI-TECH Acronym in the Editorial System: BPASTS.

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Authors and Affiliations

Juan C. Seck-Tuoh-Mora
Joselito Medina-Marin
Erick S. Martinez-Gomez
Eva S. Hernandez-Gress
Norberto Hernandez-Romero
Valeria Volpi-Leon
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Abstract

The aims of this study were to prospect Penicillium and Talaromyces species associated with Austrocedrus chilensis in sites with and without Austrocedrus Root Disease (ARD), which is caused by the pathogen Phytophthora austrocedri; and to find Penicillium sp. strains with biocontrol activity against this disease. Isolations from sites with and without the prevalence of ARD were made, and the obtained isolates were phenotypically and molecularly identified to species level. Several Penicillium species were isolated from all sites; five of them were exclusively isolated from sites with ARD. Penicillium communities were compared through multivariate analyses; communities were more complex in sites with ARD. Biocontrol activity of Penicillium and Talaromyces isolates was evaluated using co-cultures with Ph. austrocedri. Penicillium glabrum, T. amestolkiae, P. palitans, and P. crustosum showed the highest biocontrol effect. Our results highlight that Penicillium species have high biocontrol activity, which also reinforces the hypothesis that some Penicillium species could be used in formulating a control strategy.
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Authors and Affiliations

Jorge Ariel Marfetán
1 2
ORCID: ORCID
María Laura Vélez
3 4
ORCID: ORCID
Ricardo Comerio
5
ORCID: ORCID
Ana Gallo
1 6
ORCID: ORCID
Stella Romero
2
ORCID: ORCID

  1. Phytopathology and Applied Microbiology, Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Argentina
  2. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
  3. Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Phytopathology and Applied Microbiology, Centro de Investigación y Extensión Forestal Andino Patagónico (CIEFAP), Argentina
  4. Facultad de Ingeniería y Facultad de Ciencias Naturales y Ciencias de la Salud, Universidad Nacional de la Patagonia San Juan Bosco (UNPSJB), Argentina
  5. Estación Experimental Agropecuaria Anguil “Ing. Agr. Guillermo Covas”, Instituto Nacional de Tecnología Agropecuaria (INTA), Argentina
  6. Fondo para la Investigación Científica y Tecnológica (FONCYT), Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación (Agencia I+D+I), Argentina
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Abstract

This work aimed to evaluate the yam peel in a bed column packaged as a chromium(VI) ion adsorbent in an aqueous solution. Yam peel was used as adsorbent, prior washing, drying, size reduction, and selection. The experimental work consisted in determining the effect of bed depth, particle size, and temperature, keeping inlet flow = 0.75 cm 3∙s –1, pH = 2 and initial concentration of 100 mg∙dm –3. The Adsorption Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray (EDS) analysis on yam ( Dioscorea rotundata) peel showed a heterogeneous, porous structure, with functional groups characteristic in lignocellulosic materials. It was analysed regarding the influence of temperature, bed height, and adsorbent particle size on the removal efficiency; it was found that the decrease of particle size and the increase of the bed height favour the elimination of the metallic ion, with removal rates between 92.4 and 98.3%. The bed maximum adsorption capacity was 61.75 mg∙g –1, and break time of 360 min. The break curve’s adjustment to the Thomas, Yoon–Nelson, Dose–Response and Adams–Bohart models was evaluated, concluding that the Yoon–Nelson and Dose–Response models best described the behaviour of the break curve with a coefficient of determination ( R2) of 0.95 and 0.96, respectively. The results show that the bio-adsorbent studied can be used to eliminate Cr(VI) in a continuous system.
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Authors and Affiliations

Ángel Villabona-Ortíz
1
ORCID: ORCID
Candelaria Tejada-Tovar
1
ORCID: ORCID
Rodrigo Ortega Toro
2
ORCID: ORCID
Keily Peña-Romero
1
ORCID: ORCID
Ciro Botello-Urbiñez
1

  1. Universidad de Cartagena, Department of Chemical Engineering, Cartagena de Indias, Colombia
  2. Universidad de Cartagena, Department of Food Engineering, Av. del Consulado # 30 St., No. 48 152 Cartagena, Cartagena de Indias, Bolívar Cartagena de Indias, Colombia
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Abstract

The objective of this research was to evaluate the adsorption capacity of the shell biomass ( Dioscorea rotundata), taking into account the impact of temperature, bed height, and particle size on the removal of nickel(II) ions in aqueous solution in a continuous fixed-bed column system; performing the modelling of the break curve. The biomass was characterised by SEM-EDS analysis. The analysis found that it represents a rough, heterogeneous structure, rich in carbon and oxygen, with mesopores, and is suitable for removing heavy metals. It also determined the optimum parameters of the bed height, particle size, and temperature, keeping the pH and the initial concentration of the solution constant. The results revealed that the bed height and the particle size are the two most influential variables in the process. Ni(II) removal efficiencies range between 85.8 and 98.43%. It was found that the optimal conditions to maximise the efficiency of the process are temperature of 70°C, 1.22 mm particle size, and 124 mm bed height. The break curve was evaluated by fitting the experimental data to the Thomas, Adams–Bohart, Dose–Response, and Yoon– Nelson models, with the Dose–Response model showing the best affinity with a coefficient of determination R2 of 0.9996. The results obtained in this research showed that yam shell could be suggested as an alternative for use in the removal of Ni(II) ions present in an aqueous solution in a continuous system.
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Authors and Affiliations

Ángel Villabona-Ortíz
1
ORCID: ORCID
Candelaria Tejada-Tovar
1
ORCID: ORCID
Rodrigo Ortega-Toro
2
ORCID: ORCID
Keily Peña-Romero
1
ORCID: ORCID
Ciro Botello-Urbiñez
1

  1. Universidad de Cartagena, Department of Chemical Engineering, Cartagena de Indias, Colombia
  2. Universidad de Cartagena, Department of Food Engineering, Carrera 6, Cl. de la Universidad 36-100, Cartagena de Indias, Colombia

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