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73 results, page 1 of 8

Lattice algebra approach to multispectral analysis of ancient documents

JUAN CARLOS VALDIVIEZO NAVARRO GONZALO JORGE URCID SERRANO (2013)

This paper introduces a lattice algebra procedure that can be used for the multispectral analysis of historical documents and artworks. Assuming the presence of linearly mixed spectral pixels captured in a multispectral scene, the proposed method computes the scaled min- and max-lattice associative memories to determine the purest pixels that best represent the spectra of single pigments. The estimation of fractional proportions of pure spectra at each image pixel is used to build pigment abundance maps that can be used for subsequent restoration of damaged parts. Application examples include multispectral images acquired from the Archimedes Palimpsest and a Mexican pre-Hispanic codex. © 2013 OpticalSociety of America

Article

Lattice algebra Multispectral analysis Multispectral Historical documents CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA ÓPTICA ÓPTICA

Natural Disasters and Economic Growth: a synthesis of empirical evidence

Fernando Antonio Ignacio González (2021)

Natural disasters pose a serious threat globally and, in the future, their frequency and severity are expected to increase due to climate change. Empirical evidence has reported conflicting results in terms of the impact of disasters on economic growth. In this context, the present work seeks to synthesize the recent empirical evidence related to this topic. More than 650 estimates, from studies published in the last five years (2015-2020), are used. Meta-analysis and meta-regression techniques are employed. The review includes three sources (Scopus, Science Direct, and Google Scholar). The results identified the existence of a negative and significant combined effect (-0.015). Developing countries are especially vulnerable to disasters. The negative impact is greater for disasters that occurred in the last decade -in relation to previous disasters-. These findings constitute a call for attention in favor of mitigation and adaptation policies.

Article

Artículo

disasters growth GDP meta-analysis meta-regression desastres crecimiento PIB meta-análisis meta-regresión CIENCIAS SOCIALES CIENCIAS SOCIALES

Natural Disasters and Economic Growth: a synthesis of empirical evidence

Fernando Antonio Ignacio González (2021)

Natural disasters pose a serious threat globally and, in the future, their frequency and severity are expected to increase due to climate change. Empirical evidence has reported conflicting results in terms of the impact of disasters on economic growth. In this context, the present work seeks to synthesize the recent empirical evidence related to this topic. More than 650 estimates, from studies published in the last five years (2015-2020), are used. Meta-analysis and meta-regression techniques are employed. The review includes three sources (Scopus, Science Direct, and Google Scholar). The results identified the existence of a negative and significant combined effect (-0.015). Developing countries are especially vulnerable to disasters. The negative impact is greater for disasters that occurred in the last decade -in relation to previous disasters-. These findings constitute a call for attention in favor of mitigation and adaptation policies.

Article

Artículo

disasters growth GDP meta-analysis meta-regression desastres crecimiento PIB meta-análisis meta-regresión CIENCIAS SOCIALES CIENCIAS SOCIALES

Natural Disasters and Economic Growth: a synthesis of empirical evidence

Fernando Antonio Ignacio González (2021)

Natural disasters pose a serious threat globally and, in the future, their frequency and severity are expected to increase due to climate change. Empirical evidence has reported conflicting results in terms of the impact of disasters on economic growth. In this context, the present work seeks to synthesize the recent empirical evidence related to this topic. More than 650 estimates, from studies published in the last five years (2015-2020), are used. Meta-analysis and meta-regression techniques are employed. The review includes three sources (Scopus, Science Direct, and Google Scholar). The results identified the existence of a negative and significant combined effect (-0.015). Developing countries are especially vulnerable to disasters. The negative impact is greater for disasters that occurred in the last decade -in relation to previous disasters-. These findings constitute a call for attention in favor of mitigation and adaptation policies.

Article

Artículo

disasters growth GDP meta-analysis meta-regression desastres crecimiento PIB meta-análisis meta-regresión CIENCIAS SOCIALES CIENCIAS SOCIALES

Estimation of radiated energy using the EGF technique: what should be the upper limit of integration in the frequency domain?

Shri Krishna Singh (2007)

The empirical Green's function (EGF) technique is frequently used to estimate the radiated seismic energy, ER, of an earthquake. An approximation of the moment-rate spectrum, M0(f), of the target earthquake is obtained from the ratio of the spectrum of the target earthquake to the spectrum of the EGF earthquake, and the radiated seismic energy is computed by integrating f2M0 2(f) over frequency f. The choice of the upper limit of integration, fu, is critical. In this note we show that the optimum choice of fu, for the ω2-source model is given by fu/fc1∼ fc2/fc1, where fc1 and fc2 are the corner frequencies of the target and the EGF earthquakes, respectively. This result provides a useful guide in the application of the EGF technique to obtain a reliable estimate of the radiated seismic energy.

Article

TERREMOTOS ANÁLISIS EMPÍRICO MÉTODO DE ESTIMACIÓN FUNCIÓN VERDE ANÁLISIS DE FIABILIDAD SISMICIDAD Earthquake Empirical analysis Estimation method Green function Reliability analysis Seismicity CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA CIENCIAS DE LA TIERRA Y DEL ESPACIO GEOFÍSICA SISMOLOGÍA Y PROSPECCIÓN SÍSMICA concept8601 Seismology

Exploring University Mexican Students’ Quality of Intra-Mathematical Connections When Solving Tasks About Derivative Concept.

CAMILO ANDRES RODRIGUEZ NIETO FLOR MONSERRAT RODRIGUEZ VASQUEZ JAVIER GARCIA GARCIA (2021)

The quality of the intra-mathematical connections made by Mexican university students when solving tasks on the derivative was characterized. The typology of mathematical connections and the quality levels of mathematical connections were used. Interviews were conducted based on eight tasks applied to three case studies. The results showed that the quality of the intra mathematical connections: different representations, procedural, implication, part-whole and meaning of the students, is found mostly at level 2 (consistent and argued mathematical connections) and only one student presented inconsistencies to find the correctness equation of the tangent line to the curve at a point (quality level 0 connection).

Article

quality of mathematical connections derivative university students thematic analysis HUMANIDADES Y CIENCIAS DE LA CONDUCTA PEDAGOGÍA TEORÍA Y MÉTODOS EDUCATIVOS

Biohydrogen production from mixtures of agro-industrial wastes: Chemometric analysis, optimization and scaling up

ANGEL MARIO LOPEZ HIDALGO Zazil Donaxí Alvarado Cuevas Antonio de León Rodríguez (2018)

"Cheese whey (CW) and wheat straw hydrolysate (WSH) were used to produce biohydrogen by anaerobic co-digestion of multiple substrates. In this work, the influence of pH, temperature, substrates concentrations on the biohydrogen production was explored with the application of the principal component analysis (PCA) and the hierarchical clustering analysis (HCA), allowing the identification of the main clusters and the uniqueness of some experiments. Response surface methodology (RSM) was used to evaluate the individual and interactive effects of pH, temperature, CW concentration and WSH concentration in the fermentation. Optimal operational conditions obtained by RMS were 5?g?L?1 WSH, 25?g?L?1?CW, 26.6?°C and pH 7.25. With these conditions was expected 5724.5?mL H2 L?1. When optimal conditions were tested using 0.11-L anaerobic serological bottles, 1-L and 4-L bioreactors the results obtained for biohydrogen production were 4554.5?±?105, 3685?±?305 and 4132.3?±?151?mL H2 L?1, respectively; on the other hand, the biohydrogen production rate was improved from 66.6 to 89.5?mL H2 L?1 h?1. Results demonstrate that it is possible to use WSH and CW, both individually and in combination, as a substrate for the production of biohydrogen."

Article

Biohydrogen Co-digestion Dark fermentation Cheese whey Wheat straw hydrolysate Chemometric analysis CIENCIAS FÍSICO MATEMÁTICAS Y CIENCIAS DE LA TIERRA FÍSICA TERMODINÁMICA TERMODINÁMICA

Natural Disasters and Economic Growth: a synthesis of empirical evidence

Fernando Antonio Ignacio González (2021)

Natural disasters pose a serious threat globally and, in the future, their frequency and severity are expected to increase due to climate change. Empirical evidence has reported conflicting results in terms of the impact of disasters on economic growth. In this context, the present work seeks to synthesize the recent empirical evidence related to this topic. More than 650 estimates, from studies published in the last five years (2015-2020), are used. Meta-analysis and meta-regression techniques are employed. The review includes three sources (Scopus, Science Direct, and Google Scholar). The results identified the existence of a negative and significant combined effect (-0.015). Developing countries are especially vulnerable to disasters. The negative impact is greater for disasters that occurred in the last decade -in relation to previous disasters-. These findings constitute a call for attention in favor of mitigation and adaptation policies.

Article

Artículo

disasters growth GDP meta-analysis meta-regression desastres crecimiento PIB meta-análisis meta-regresión CIENCIAS SOCIALES CIENCIAS SOCIALES

Emotion classification and sentiment analysis for sustainable agricultural development: exploring available tools for analyzing African farmer interviews

Gideon Kruseman Brendan Brown (2021)

The emerging 4th industrial revolution is having a profound effect on the direction of agrarian development. Big data technologies are becoming embedded within all walks of life, leading to both significant advancements in utility and to critical ethical concerns about the organization of the social world. Academic attention is growing into how such technologies can be employed for farmers; using enriched forms of data collection to account for contextually embedded factors in smallholder decision making. Further, in the context of ongoing COVID-19 restrictions, research is increasingly being conducted remotely. This removes a significant interpersonal dimension from studies, a particular concern for those which deal with sensitive data such as gender empowerment. In this paper we explore emotion classification and sentiment analysis of text and audio data of farmers' interviews in eastern and southern Africa and their evaluation of a set of sustainable agricultural practices. With this relatively benign dataset, which is known not to include any instances of affective behavior beyond normal discussion of farming techniques, we attempt to test the viability of these tools and what steps are necessary to make them reliable and accessible to researchers. Findings indicate additional insight can be made to support qualitative study, in several cases demonstrating a convergence between traditional anthropological assessment and expected emotional reaction. There are also unexpected responses and unforeseen learning for the process of qualitative data collection and processing. For future research and interventions, however, a series of limitations and developments are identified for this methodology to mature.

Book

CIENCIAS AGROPECUARIAS Y BIOTECNOLOGÍA FARMERS FARMERS' ATTITUDES INTERVIEWS DATA COLLECTION DATA ANALYSIS