3,406 research outputs found
Semiparametric three step estimation methods in labor supply models
The aim of this paper is to provide an alternative way of specification and estimation of a labor supply model. The proposed estimation procedure can be included in the so called predicted wage methods and its main interest is twofold .. First, under standard assumptions in studies of labor supply, the estimator based on predicted wages is shown to be consistent and asymptotically normal. Moreover, we propose also a consistent estimator of the asymptotic covariance matrix. In the main part of the paper we introduce a semiparametric estimator based on marginal integration techniques that allows for nonlinear relationships between the labor supply variable and its covariates. We show that also the wage equation could be modeled nonparametrically. The asymptotic properties of the estimators are given. Finally, in a detailed application we compare the results empirically against those obtained in standard three step estimators based on predicted wages
The Microbiota of the Human Mammary Ecosystem
Human milk contains a dynamic and complex site-specific microbiome, which is not assembled in an aleatory way, formed by organized microbial consortia and networks. Presence of some genera, such as Staphylococcus, Streptococcus, Corynebacterium, Cutibacterium (formerly known as Propionibacterium), Lactobacillus, Lactococcus and Bifidobacterium, has been detected by both culture-dependent and culture-independent approaches. DNA from some gut-associated strict anaerobes has also been repeatedly found and some studies have revealed the presence of cells and/or nucleic acids from viruses, archaea, fungi and protozoa in human milk. Colostrum and milk microbes are transmitted to the infant and, therefore, they are among the first colonizers of the human gut. Still, the significance of human milk microbes in infant gut colonization remains an open question. Clinical studies trying to elucidate the question are confounded by the profound impact of non-microbial human milk components to intestinal microecology. Modifications in the microbiota of human milk may have biological consequences for infant colonization, metabolism, immune and neuroendocrine development, and for mammary health. However, the factors driving differences in the composition of the human milk microbiome remain poorly known. In addition to colostrum and milk, breast tissue in lactating and non-lactating women may also contain a microbiota, with implications in the pathogenesis of breast cancer and in some of the adverse outcomes associated with breast implants. This and other open issues, such as the origin of the human milk microbiome, and the current limitations and future prospects are addressed in this review.Peer reviewe
Finite sample behavior of two step estimators in selection models
The problem of specification errors in sample selection models has received considerable attention both theoretically and empirically. However, very few is known about the finite sample behavior of two step estimators. In this paper we investigate by simulations both bias and finite sample distribution of these estimators when ignoring heteroskedasticity in the sample selection mechanism. It turns out that under conditions traditionally faced by practitioners, the misspecified parametric two step estimator (Heckman, 1979) performs better, in finite sample sizes, than the robust semiparametric one (Ahn and Powell, 1993). Moreover, under very general conditions, we show that the asymptotic bias of the parametric two step estimator is linear in the covariance between the sample selection and the participation equation.The first two authors wish to thank the Dirección General de Enseñanza Superior, research project PB96-C05-03 for its financial support. The third author acknowledges financial support from the DGICYT, research project PB94-0602
Artificial Intelligence Applied to Conceptual Design. A Review of Its Use in Architecture
Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG[Abstract] Conceptual architectural design is a complex process that draws on past experience and creativity to generate new designs. The application of artificial intelligence to this process should not be oriented toward finding a solution in a defined search space since the design requirements are not yet well defined in the conceptual stage. Instead, this process should be considered as an exploration of the requirements, as well as of possible solutions to meet those requirements.
This work offers a tour of major research projects that apply artificial intelligence solutions to architectural conceptual design. We examine several approaches, but most of the work focuses on the use of evolutionary computing to perform these tasks. We note a marked increase in the number of papers in recent years, especially since 2015. Most employ evolutionary computing techniques, including cellular automata. Most initial approaches were oriented toward finding innovative and creative forms, while the latest research focuses on optimizing architectural form.This project was supported by the General Directorate of Culture, Education and University Management of Xunta de Galicia (Ref. ED431G/01, ED431D 2017/16), and the Spanish Ministry of Economy and Competitiveness via funding of the unique installation BIOCAI (UNLC08-1E-002, UNLC13-13-3503) and the European Regional Development Funds (FEDER)Xunta de Galicia; ED431G/01Xunta de Galicia; ED431D 2017/1
Application of Ligilactobacillus salivarius CECT5713 to Achieve Term Pregnancies in Women with Repetitive Abortion or Infertility of Unknown Origin by Microbiological and Immunological Modulation of the Vaginal Ecosystem
In this study, the cervicovaginal environment of women with reproductive failure (repetitive abortion, infertility of unknown origin) was assessed and compared to that of healthy fertile women. Subsequently, the ability of Ligilactobacillus salivarius CECT5713 to increase pregnancy rates in women with reproductive failure was evaluated. Vaginal pH and Nugent score were higher in women with reproductive failure than in fertile women. The opposite was observed regarding the immune factors TGF-β 1, TFG-β 2, and VEFG. Lactobacilli were detected at a higher frequency and concentration in fertile women than in women with repetitive abortion or infertility. The metataxonomic study revealed that vaginal samples from fertile women were characterized by the high abundance of Lactobacillus sequences, while DNA from this genus was practically absent in one third of samples from women with reproductive failure. Daily oral administration of L. salivarius CECT5713 (~9 log10 CFU/day) to women with reproductive failure for a maximum of 6 months resulted in an overall successful pregnancy rate of 56%. The probiotic intervention modified key microbiological, biochemical, and immunological parameters in women who got pregnant. In conclusion, L. salivarius CECT5713 has proved to be a good candidate to improve reproductive success in women with reproductive failure.Sección Deptal. de Farmacia Galénica y Tecnología Alimentaria (Veterinaria)Fac. de VeterinariaTRUEContract 291-2018 established between Complutense University of Madrid and Biosearch Life S. A. (Granada, Spain)Irma Castro is the recipient of a predoctoral contract (BES-2017-080713) from the Ministerio de Ciencia, Innovación y Universidades (Spain)pu
Finite sample behavior of two step estimators in selection models
The problem of specification errors in sample selection models has received considerable attention both theoretically and empirically. However, very few is known about the finite sample behavior of two step estimators. In this paper we investigate by simulations both bias and finite sample distribution of these estimators when ignoring heteroskedasticity in the sample selection mechanism. It turns out that under conditions traditionally faced by practitioners, the misspecified parametric two step estimator (Heckman, 1979) performs better, in finite sample sizes, than the robust semiparametric one (Ahn and Powell, 1993). Moreover, under very general conditions, we show that the asymptotic bias of the parametric two step estimator is linear in the covariance between the sample selection and the participation equation.sample selection models, semiparametric models, finite sample analysis, misspecification error, heteroskedasticity, Heckman two step estimator
Effect of different digestates derived from anaerobic co-digestion of Olive Mill Solid Waste (OMSW) and various microalgae as fertilizers for the cultivation of ryegrass
Aims
The aim of this work was to evaluate the fertilizing effect of three anaerobic co-digestates on the growth of the herbaceous plant Lolium rigidum.
Methods
Nine treatments, combining different nutritional solutions (organic and inorganic) and number of fertilizations (one or two) were evaluated. Organic nutritive solution: plants grown with different olive mill solid waste (OMSW) -microalgae co-digestates: 75% OMSW-25% Raphidocelis subcapitata, volatile solids (VS) basis (OMSW-Rs); 50% OMSW- 50% Chlamydomonas Reinhardtii, VS basis (OMSW-Chl); and 75% OMSW-25% Secenedesmus quadricauda, VS basis (OMSW-Sq). Inorganic nutritive solution (INS): plants grown with inorganic Hoagland nutrient solution at 50%. After 60 days of experimentation, biometric and nutritional characteristics and photosynthetic activity were measured.
Results
The results showed a favourable growth, development and nutritional quality of L. rigidum plants when digestates obtained from the anaerobic co-digestion of OMSW-microalgae are used as organic nutritional solutions as opposed to INS ones. The highest total biomass of L. rigidum was obtained with the treatments that involved two fertilizations. No inhibition due to excess nutrients was observed. A higher root/shoot ratio was achieved with the digestates of OMSW-Rs and OMSW-Ch as compared to that obtained with OMSW-Sq (F = 17.23 p ≤ 0.001). The nitrogen shoot biomass obtained after the organic treatments with the above-mentioned co-digestates was higher than that obtained after the inorganic treatment. Net photosynthesis rates did not present differences in the co-digestates treatments, being equal or superior to the INS treatments.
Conclusions
The use of the anaerobic co-digestates from OMSW-microalgae can be considered a viable and promising alternative to inorganic fertilization
Factores condicionantes de la sostenibilidad como una dimensión estratégica del desarrollo turístico mexicano
This paper proposes the Delphi analysis to identify and analyze the key factors of sustainability in Mexicoʼs present tourism-development model. The importance of the results is due to the fact that sustainability has become a central aspect in the competitiveness of any tourism destination. In this sense, Mexicoʼs current shortfalls may limit the role of tourism in the economic development of the country. So, the definition of the sustainability factors in Mexico leads to the design and implementation of strategies to overcome such situation.A través del análisis Delphi, en este trabajo se identifican y analizan los principales condicionantes de la sostenibilidad del actual modelo de desarrollo turístico mexicano. La importancia de los resultados obtenidos radica en que la sostenibilidad se ha convertido en un factor clave en la capacidad de competir de cualquier destino turístico, y México presenta actualmente serios déficit en este aspecto, lo que, a su vez, puede constreñir la contribución del turismo al desarrollo económico del país. De ahí que conocer los factores que condicionan la sostenibilidad del turismo mexicano contribuya al diseño e implementación de estrategias para superar esta situación
Fabrication and deposition of copper and copper oxide nanoparticles by laser ablation in open air
The proximity of the “post-antibiotic era”, where infections and minor injuries could be a cause of death, there are urges to seek an alternative for the cure of infectious diseases. Copper nanoparticles and their huge potential as a bactericidal agent could be a solution. In this work, Cu and Cu oxide nanoparticles were synthesized by laser ablation in open air and in argon atmosphere using 532 and 1064 nm radiation generated by nanosecond and picosecond Nd:YVO4 lasers, respectively, to be directly deposited onto Ti substrates. Size, morphology, composition and the crystalline structure of the produced nanoparticles have been studied by the means of field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), the energy dispersive spectroscopy of X-rays (EDS), selected area electron diffraction (SAED) and X-ray diffraction (XRD). The UV-VIS absorbance of the thin layer of nanoparticles was also measured, and the antibacterial capacity of the obtained deposits tested against Staphylococcus aureus. The obtained deposits consisted of porous coatings composed of copper and copper oxide nanoparticles interconnected to form chain-like aggregates. The use of the argon atmosphere contributed to reduce significantly the formation of Cu oxide species. The synthesized and deposited nanoparticles exhibited an inhibitory effect upon S. aureus.Peer ReviewedPostprint (published version
Resistencia a Tuta absoluta en una entrada de la especie silvestre de tomate Solanum pimpinellifolium
2 páginas, 1 figura, 1 tabla.-- Artículo publicado en la revista profesional de sanidad vegetal.-- et al.[EN]: We previously found resistance to pests (twospotted spider mite and whitefly)
based on type IV glandular trichomes and acylsucrose production in an accession
of the wild tomato species S. pimpinellifolium from the germplasm collection at the
Experimental Station La Mayora – CSIC. Resistance to the South American tomato
pinworm of that accession and plant materials derived from it was investigated in
greenhouse conditions at CNPH (Brasilia, Brazil) and, when Tuta absoluta was
introduced into Spain, at Exp. Sta. La Mayora (Málaga, southern Spain). Genotypes
carrying type IV glandular trichomes showed reduced pest damage, especially on
young, apical leaves. Possibility for control of Tuta by the utilization of resistant
tomato cultivars looks forward to future breeding programmes for the trait.[ES]: Una entrada de la especie silvestre de tomate S. pimpinellifolium del banco de germoplasma de la Estación Experimental La Mayora-CSIC presenta resistencia a plagas (araña roja y mosca blanca) merced a sus tricomas glandulares de tipo IV y producción de acilsacarosas. Con el fin de estudiar si esta entrada y otros genotipos de tomate de ella derivados eran también resistentes a T. absoluta, se realizaron experimentos en condiciones de invernadero en CNPH (Brasilia, Brasil) y, una vez que Tuta se introdujo en España, en la E.E. La Mayora (Algarrobo, Málaga). Los genotipos con tricomas de tipo IV sufrieron menores daños por la plaga, especialmente en las hojas apicales, más jóvenes. La posibilidad del control de Tuta mediante la utilización de variedades resistentes queda abierta a futuros programas de mejora genética del carácter.Trabajo financiado por MICINN-FEDER (Proyecto AGL2007-66760-C02-02/AGR).Peer reviewe
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