Elementos cognitivos para el análisis ergonómico del trabajo

Esta nota de investigación presenta algunos de los elementos de base para el análisis de la actividad del trabajo desde la perspectiva de la ergonomía cognitiva. Para poder aproximarse a la relación existente entre los procesos cognitivos en el trabajo y la noción de ergonomía es necesario abordar inicialmente la definición de esta disciplina. El termino ergonomía, acuñado en 1940 por el psicólogo británico Hywel Murrell, (del Griego ergo: trabajo + nomos: ley, conocimiento) delimita un campo de investigación disciplinar de las ciencias del trabajo. La ergonomía tiene por objetivo adaptar el trabajo al hombre, así como mejorar las condiciones de trabajo y las relaciones hombre-máquina. La ergonomía puede ser preventiva, de concepción, correctiva y cognitiva. La ergonomía es una disciplina que nació con el propósito de integrar, en la concepción de los sistemas de trabajo, los conocimientos existentes sobre el hombre en situación de trabajo

The citation merit of scientific publications

We propose a new method to assess the merit of any set of scientific papers in a given field based on the citations they receive. Given a citation indicator, such as the mean citation or the h-index, we identify the merit of a given set of n articles with the probability that a randomly drawn sample of n articles from a reference set of articles in that field presents a lower citation index. The method allows for comparisons between research units of different sizes and fields. Using a dataset acquired from Thomson Scientific that contains the articles published in the periodical literature in the period 1998-2007, we show that the novel approach yields rankings of research units different from those obtained by a direct application of the mean citation or the h-index.Citation analysis, Citation merit, Mean citation, h-index

The skewness of science in 219 sub-fields and a number of aggregates

This paper studies evidence from Thomson Scientific about the citation process of 3.7 million articles published in the period 1998-2002 in 219 Web of Science categories, or sub-fields. Reference and citation distributions have very different characteristics across sub-fields. However, when analyzed with the Characteristic Scores and Scales technique, which is replication and scale invariant, the shape of these distributions over three broad categories of articles appears strikingly similar. Reference distributions are mildly skewed, but citation distributions with a five-year citation window are highly skewed: the mean is twenty points above the median, while 9-10% of all articles in the upper tail account for about 44% of all citations. The aggregation of sub-fields into disciplines and fields according to several aggregation schemes preserve this feature of citation distributions. It should be noted that when we look into subsets of articles within the lower and upper tails of citation distributions the universality partially breaks down. On the other hand, for 140 of the 219 sub-fields the existence of a power law cannot be rejected. However, contrary to what is generally believed, at the sub-field level the scaling parameter is above 3.5 most of the time, and power laws are relatively small: on average, they represent 2% of all articles and account for 13.5% of all citations. The results of the aggregation into disciplines and fields reveal that power law algebra is a subtle phenomenon.

A comparison of the scientific performance of the U.S. and the European Union at the turn of the 21st century.

In this paper, scientific performance is identified with the impact that journal articles have through the citations they receive. In 15 disciplines, as well as in all sciences as a whole, the EU share of total publications is greater than that of the U.S. However, as soon as the citations received by these publications are taken into account the picture is completely reversed. Firstly, the EU share of total citations is still greater than the U.S. in only seven fields. Secondly, the mean citation rate in the U.S. is greater than in the EU in every one of the 22 fields studied. Thirdly, since standard indicators—such as normalized mean citation ratios—are silent about what takes place in different parts of the citation distribution, this paper compares the publication shares of the U.S. and the EU at every percentile of the world citation distribution in each field. It is found that in seven fields the initial gap between the U.S. and the EU widens as we advance towards the more cited articles, while in the remaining 15 fields—except for Agricultural Sciences—the U.S. always surpasses the EU when it counts, namely, at the upper tail of citation distributions. Finally, for all sciences as a whole the U.S. publication share becomes greater than that of the EU for the top 50% of the most highly cited articles. The data used refers to 3.6 million articles published in 1998–2002, and the more than 47 million citations they received in 1998–2007Research performance; Citation analysis; Scientific ranking; European paradox;

Localization of fermions in different domain wall models

Localization of fermions is studied in different gravitational domain wall models. These are generalizations of the brane-world models considered by Randall and Sundrum, but which also allow gravitational localization. Therefore, they might be considered as possible realistic scenarios for phenomenology.Comment: RevTeX, 6 pages, 10 figure

A comparison of the scientific performance of the U. S. and the European Union at the turn of the XXI century.

In this paper, scientific performance is identified with the impact journal articles achieve through the citations they receive. The empirical exercise refers to 3.6 million articles published in 1998-2002 in 22 scientific fields, and the more than 47 million citations they receive in 1998-2007. The first finding is that a failure to exclude co-authorship among member countries within the EU (European Union) may lead to a serious upward bias in the assignment of articles to this geographical area. In the second place, standard indicators, such as normalized mean citation ratios, are silent about what takes place in different parts of the citation distribution. Consequently, this paper compares the publication shares of the U.S. and the EU at every percentile of the world citation distribution in each field. In 15 disciplines, as well as in all sciences as a whole, the EU share of total publications is greater than that of the U.S. one. But as soon as the citations received by these publications are taken into account the picture is completely reversed. The mean citation rate in the U.S. is greater than in the EU in every one of the 22 fields. In seven fields, the initial gap between the U.S. and the EU widens up as we advance towards the more cited articles, while in the remaining 15 fields –except for Agricultural Sciences– the U.S. always surpasses the EU when it counts, namely, at the upper tail of citation distributions. For all sciences as a whole, the U.S publication share becomes greater than that of the EU one for the top 50% of the most highly cited articles.

The skewness of science in 219 sub-fields and a number of aggregates

This paper studies evidence from Thomson Scientific about the citation process of 3.7 million articles published in the period 1998-2002 in 219 Web of Science categories, or sub-fields. Reference and citation distributions have very different characteristics across sub-fields. However, when analyzed with the Characteristic Scores and Scales technique, which is size and scale independent, the shape of these distributions appear extraordinarily similar. Reference distributions are mildly skewed, but citation distributions with a five-year citation window are highly skewed: the mean is twenty points above the median, while 9-10% of all articles in the upper tail account for about 44% of all citations. The aggregation of sub-fields into disciplines and fields according to several aggregation schemes preserve this feature of citation distributions. On the other hand, for 140 of the 219 sub-fields the existence of a power law cannot be rejected. However, contrary to what is generally believed, at the sub-field level the scaling parameter is above 3.5 most of the time, and power laws are relatively small: on average, they represent 2% of all articles and account for 13.5% of all citations. The results of the aggregation into disciplines and fields reveal that power law algebra is a subtle phenomenon.

When All Agents Die: Analyzing the “Failures” in an Agent-Based Model of Human Foraging

When running a simulated social-historic scenario, we often find situations in which all agents die, even though the simulated population appears to grow in the first steps. Is this a signal that something is wrong in the computer model or its implementation? We analyze this issue in our computer model of cooperation and cultural diversity among hunter-gatherers in prehistory. We have calculated more than 11,000 possible parameter combinations, taking into account the growth and decay of the population and the availability of resources in the environment. When the initial population is too scarce or too big for the local availability of resources, it begins to decrease until it disappears. This can be a very trivial test for the Malthus condition, but we have discovered that there are other important correlations affecting social and economic factors that should be explored