La popularidad de las especies. Las diez principales

La base de datos Science Citation Index nos permite fácilmente obtener una medida de la popularidad científica de las especies animales, plantas y minerales. Utilizando en esta base de datos la estrategia de búsqueda en título, resumen y palabras clave hemos cuantificado cuántas veces ha sido incluido el nombre de una especie en los artículos publicados desde 1945 hasta nuestros días. La variación del número de citas con respecto al orden que ocupan en el ránking sigue una función altamente trascendente: y = a x–b e–cx. En este ránking, las 10 especies más citadas tienen todas un fuerte carácter antrópic

Óxidos de ferro e matéria orgânica na disponibilidade de fósforo no solo

Continuous crop expansion has led to a growing demand for phosphate fertilizers. A sound knowledge of the dynamics of phosphorus, and its interaction with iron oxides and organic matter, can be useful to develop effective strategies for sustainable management, especially in a scenario of increasing shortage of mineral phosphate resources. In this paper, we review the relationship of phosphate to iron oxides and organic matter, and its effect on phosphorus availability. Crops typically obtain phosphate from weathered minerals and dissolved fertilizers. However, the amount of phosphorus present in the soil solution depends on the extent to which it is adsorbed or desorbed by iron oxides, which may be influenced by interactions with organic matter. Therefore, systems for fertilizer recomendation based on methodologies considering interactions between soil components such as oxides and organic matter, and the phosphorus sorption capacity resulting from such interactions (e.g. residual P analysis), may be more reliable to ensure efficient, rational use of phosphate.A contínua expansão da produção agrícola tem levado a uma crescente demanda de fertilizantes fosfatados. O conhecimento da dinâmica do fósforo no solo e suas interações com óxidos de ferro e matéria orgânica podem ser uteis no desenvolvimento de estratégias eficientes para o manejo sustentável, especialmente em um cenário de crescente escassez de fontes de minerais fosfatados. Nesta revisão bibliográfica foi abordado a relação do fósforo com óxidos de ferro e matéria orgânica, e seu efeito na disponibilidade de fósforo. As culturas, normalmente, obtém fosfato de minerais intemperizados ou fertilizantes dissolvidos. No entanto, a quantidade de fósforo presente na solução do solo depende das reações de adsorção e dessorção por óxidos de ferro, as quais podem ser influenciadas por interações com a matéria orgânica. Portanto, os sistemas de recomendação de fertilizantes com base em metodologias que consideram as interações entre componentes do solo, tais como óxidos e matéria orgânica, e a capacidade de adsorção de fósforo, resultantes de tais interações (por exemplo, análise de P remanescente), pode ser mais confiável para garantir o uso eficiente e racional de fertilizantes fosfatados

Control of earth-like magnetic fields on the transformation of ferrihydrite to hematite and goethite

Hematite and goethite are the two most abundant iron oxides in natural environments. Their formation is controlled by multiple environmental factors; therefore, their relative concentration has been used widely to indicate climatic variations. In this study, we aimed to test whether hematite and goethite growth is influenced by ambient magnetic fields of Earth-like values. Ferrihydrite was aged at 95 °C in magnetic fields ranging from ~0 to ~100 μT. Our results indicate a large influence of the applied magnetic field on hematite and goethite growth from ferrihydrite. The synthesized products are a mixture of hematite and goethite for field intensities <~60 μT. Higher fields favour hematite formation by accelerating ferrimagnetic ferrihydrite aggregation. Additionally, hematite particles growing in a controlled magnetic field of ~100 μT appear to be arranged in chains, which may be reduced to magnetite keeping its original configuration, therefore, the presence of magnetic particles in chains in natural sediments cannot be used as an exclusive indicator of biogenic magnetite. Hematite vs. goethite formation in our experiments is influenced by field intensity values within the range of geomagnetic field variability. Thus, geomagnetic field intensity could be a source of variation when using iron (oxyhydr-)oxide concentrations in environmental magnetism.This study was supported by the National Natural Science Foundation of China (grants 41504055, 41430962, 41374073, and 41025013). Z.X.J. further acknowledges support from the China Postdoctoral Science Foundation. A.P.R. acknowledges support from the Australian Research Council (grants DP110105419 and DP120103952)

Estimating the concentration of aluminum-substituted hematite and goethite using diffuse reflectance spectrometry and rock magnetism: Feasibility and limitations

Hematite and goethite in soils are often aluminum(Al) substituted, which can dramatically change their and magnetic properties and bias abundance estimates using diffuse reflectance spectroscopy (DRS) and magnetic techniques. In this study, synthetic Al-substituted hematites and goethites and two Chinese loess/paleosol sequences were investigated to test the feasibility and limitations of estimating Al-hematite and Al-goethite concentration. When Al substitution is limited (Al/(Al+ Fe) molar ratio<~8%), the reflectance spectrumprovides a reliable estimate of the goethite/hematite concentration ratio. New empirical relationships between the DRS band intensity ratio and the true concentration goethite/hematite ratio are estimated as goethite/hematite= 1.56 × (I₄₂₅ nm/I₅₃₅ nm) or goethite/hematite= 6.32 × (I₄₈₀ nm/I₅₃₅ nm), where I₄₂₅ nm, I₄₈₀ nm, and I₅₃₅ nm are the amplitudes of DRS second-derivative curves for characteristic bands at ~425 nm, ~480 nm, and ~535 nm, respectively. High Al substitution (> ~8%) reduces DRS band intensity, which leads to biased estimates of mineral concentration. Al substitution and grain size exert a control on coercivity distributions of hematite and goethite and, thus, affect the hard isothermal remanent magnetization. By integrating DRS and magneticmethods, we suggest a way to constrain hematite and goethite Al substitution in natural loess. Results indicate that hematite and goethite in Chinese loess have Al contents lower than ~8% and, thus, that DRS can be used to trace hematite and goethite concentration variations.This study was supported by the National Natural Science Foundation of China (41374073 and 41430962), the National Program on Global Changes and Air-Sea Interaction (GASI-04-01-02), and the Chinese Continental Shelf Deep Drilling Program (GZH201100202). Pengxiang Hu was further supported by the China Scholarship Council ([2013] 3009). David Heslop and Andrew Roberts were supported by Australian Research Council Discovery Project DP110105419

Magnetism of Al-substituted magnetite reduced from Al-hematite

Aluminum-substituted magnetite (Al-magnetite) reduced from Al-substituted hematite or goethite (Al-hematite or Al-goethite) is an environmentally important constituent of magnetically enhanced soils. In order to characterize the magnetic properties of Al-magnetite, two series of Al-magnetite samples were synthesized through reduction of Al-hematite by a mixed gas (80% CO₂ and 20% CO) at 395°C for 72 h in a quartz tube furnace. Al-magnetite samples inherited the morphology of their parent Al-hematite samples, but only those transformed from Al-hematite synthesized at low temperature possessed surficial micropores, which originated from the release of structural water during heating. Surface micropores could thus serve as a practical fingerprint of fire or other high-temperature mineralogical alteration processes in natural environments, e.g., shear friction in seismic zones. In addition, Al substitution greatly affects the magnetic properties of Al-magnetite. For example, coercivity (Bc) increases with increasing Al content and then decreases slightly, while the saturation magnetization (Ms), Curie temperature (Tc), and Verwey transition temperature (Tv) all decrease with increasing Al content due to crystal defect formation and dilution of magnetic ions caused by Al incorporation. Moreover, different trends in the correlation between Tc and Bc can be used to discriminate titanomagnetite from Al-magnetite, which is likely to be important in environmental and paleomagnetic studies, particularly in soil.This study was supported by National Program on Global Change and Air-Sea Interaction (GASI-04-01-02), the National Natural Science Foundation of China (grants 41504055, 41430962, 41374073, and 41025013), and Chinese Continental Shelf Deep Drilling Program (GZH201100202). Z.X.J. further acknowledges support from the China Postdoctoral Science Foundation. A.P.R. and D.H. acknowledge support from the Australian Research Council (grants DP110105419 and DP120103952)

Soil Nutrients Effects on the Performance of Durum Wheat Inoculated with Entomopathogenic Fungi

Entomopathogenic fungi (EFs) are widely used as biological control agents. However, some strains of Beauveria bassiana and Metarhizium brunneum can also promote plant growth and increase nutrient uptake. We examined the effects of soil properties on the performance of Triticum durum inoculated by seed dressing with these EFs and grown on 12 agricultural soils. The plants were supplied with all nutrients except P and Zn (essential for yield and the grain quality of wheat). Fungal inoculation increased the grain yield and harvest index significantly with B. bassiana (17% and 14%, respectively) but not with M. brunneum (6% and 6%, respectively). The increase in grain yield was positively and moderately correlated with the soil available phosphorus (POlsen) in plants inoculated with B. bassiana and with the soil content in poorly crystalline Fe oxides with M. brunneum. In addition, the increase in aerial dry matter resulting from inoculation with B. bassiana was negatively correlated with soil available Zn. Furthermore, the observed increase in grain yields due to fungal inoculation resulted in P and Zn grain dilution (grain nutrient concentrations decrease). Inoculation with B. bassiana increased grain Zn uptake and the proportion of Zn in grain relative to that in aerial dry matter. Success in the mutualistic relationship between EF and wheat plants depends on the fungal strain and soil properties

Photocatalytic fixation of NOx in soils

Nitrogen oxides (NOx = NO + NO2) are important atmospheric pollutants that are directly harmful to human health. Recently in urban and industrial areas, synthetic materials have been developed and deployed to photocatalytically oxidize NOx to nitrate (NO3−) in order to improve air quality. We show that the natural presence of small amounts (≤5%) of titanium oxides, such as anatase and rutile, can also drive NOx oxidation to nitrate in soils under UV–visible irradiation. The NO uptake coefficients ranged between 0.1 × 10−6 for sandy soils to 6.4 × 10−5 in the case of tropical clay soils; the latter comparable in efficiency to current industrial man-made catalysts. This photocatalytic N-fixation mechanism offers a new strategy for NOx mitigation from the atmosphere by transforming it into nitrate, and simultaneously provides an energy efficient source of essential fertilizer to agriculture

Elaboración de un cuestionario para evaluar el nivel de sostenibilidad de los estudiantes de grados en ingeniería TIC

Naciones Unidas aprobó en 2015 una agenda que incluye 17 objetivos del desarrollo sostenible de carácter integrado e indivisible, que conjugan las tres dimensiones del desarrollo sostenible: económica, social y ambiental. En la lucha por solucionar problemas de carácter global, resulta crucial el papel de la educación y la implicación de los educadores de todos los niveles y disciplinas. Mediante su contribución, la ciudadanía puede adquirir una visión adecuada de los problemas y desafíos que afectan a la humanidad y, de ese modo, puede intervenir en la toma de decisiones fundamentales. Un equipo de investigadores de diez universidades españolas que forman parte del Proyecto EDINSOST (Educación e Innovación Social para la Sostenibilidad) está trabajando en definir cómo se debe integrar la competencia Sostenibilidad en las distintas titulaciones del sistema universitario español. Uno de los objetivos del proyecto es medir el grado de adquisición de las competencias en sostenibilidad en estudiantes y profesores. Para definir las competencias en sostenibilidad que los estudiantes deberían tener al finalizar sus estudios, se diseñaron los mapas de sostenibilidad de catorce titulaciones. A partir de estos mapas, se ha creado un cuestionario que permite evaluar la competencia en sostenibilidad de los estudiantes universitarios. Este cuestionario debe permitir tanto determinar el conocimiento previo de los estudiantes cuando comienzan una asignatura o un Grado, como el nivel alcanzado cuando acaban dicha asignatura y/o Grado. Con estos datos podrán elaborarse propuestas de capacitación adecuadas y estudiar su efectividad. En este trabajo se presenta el proceso de elaboración de un cuestionario orientado a determinar el nivel de la competencia sostenibilidad de los estudiantes de grados en ingeniería TIC.The United Nations adopted in 2015 an agenda that includes 17 sustainable development objectives of an integrated and indivisible nature, which combine the three dimensions of sustainable development: economic, social and environmental. In the struggle to solve problems of a global nature, the role of education and the involvement of educators of all levels and disciplines is crucial. Through its contribution, citizens can acquire an adequate vision of the problems and challenges that affect humanity and, in this way, they may intervene in the making of fundamental decisions. A team of researchers from ten Spanish universities that are part of the EDINSOST Project (Education and Social Innovation for Sustainability) is working to define how the Sustainability competency should be integrated into the different degrees of the Spanish university system. One of the objectives of the project is to measure the degree of acquisition of sustainability competencies in students and teachers. To define the sustainability competencies that students should have at the end of their studies, the sustainability maps of fourteen degrees were designed. Based on these maps, a questionnaire has been created to assess the competence in sustainability of university students. This questionnaire should allow to determine the prior knowledge of the students when they start a subject or a Degree, as well as the level reached when they finish this subject and / or Degree. With these data, appropriate training proposals can be prepared and their effectiveness studied. This paper presents the process of developing a questionnaire aimed at determining the level of competency in sustainability of students of ICT Engineering Degrees.EDU2015-65574-R (MINECO-FEDER

Prediction of chromium by diffuse reflectancy for edaphic materials of the locality of Nonogasta, La Rioja

La espectroscopía de reflectancia difusa constituye una valiosa fuente de información precisa y económica de las propiedades del suelo. La determinación de metales pesados en suelos contaminados es un proceso costoso y con un elevado tiempo de procesamiento de muestras. Así se evaluó la potencialidad de técnicas espectroscópicas para la estimación indirecta de la contaminación por cromo (Cr), en un material afectado por la actividad de una curtiembre en la Localidad de Nonogasta, La Rioja. Las muestras contaminadas se asociaron significativamente con los parámetros Munsell de matiz Y y con la luminosidad aumentando su coeficiente de determinación cuando se incluyeron el CO, pH y CE. Para las muestras no contaminadas, se encontraron asociaciones significativas con el YR de Munsell también mejorando el coeficiente cuando se incluyeron las variables edáficas. Estos resultados son auspiciosos, permitiendo avanzar en la exploración de estas metodologías para la estimación y monitoreo de metales pesados en suelos contaminados.Centro de Investigaciones Geológica