Agricultura urbana, condición para el desarrollo sostenible y la mejora del paisaje

Este artículo resulta de investigaciones en torno al “enverdecimiento” de las ciudades y las oportunidades de la agricultura urbana para la alimentación de una población en constante aumento que no trabaja la tierra. También es fruto de actividades de mejora de ambientes urbanos realizadas con la Escuela de Ingenieros Agrónomos de la Universidad Politécnica de Madrid. A través de casos de agricultura urbana, entendiendo por ella el conjunto de prácticas para la producción de alimentos y plantas ornamentales dentro de las ciudades y en sus entornos, se analizan alternativas para la recuperación de espacios construidos e incremento de la calidad de vida de la población. Todo ello se traduce, además, en creación de riqueza y mejora del paisaje urbano, siempre desde criterios de sostenibilidad que favorecen el desarrollo local desde la Cumbre de la Tierra de Río de 1992 y la Conferencia sobre Desarrollo Sostenible Río+20 de 2013.

Characterization of T-type calcium current and its contribution to electrical activity in rabbit urethra.

Rabbit urethral smooth muscle cells were studied at 37 degrees C by using the amphotericin B perforated-patch configuration of the patch-clamp technique, using Cs(+)-rich pipette solutions. Two components of current, with electrophysiological and pharmacological properties typical of T- and L-type Ca(2+) currents, were recorded. Fitting steady-state inactivation curves for the L current with a Boltzmann equation yielded a V(1/2) of -41 +/- 3 mV. In contrast, the T current inactivated with a V(1/2) of -76 +/- 2 mV. The L currents were reduced by nifedipine (IC(50) = 225 +/- 84 nM), Ni(2+) (IC(50) = 324 +/- 74 microM), and mibefradil (IC(50) = 2.6 +/- 1.1 microM) but were enhanced when external Ca(2+) was substituted with Ba(2+). The T current was little affected by nifedipine at concentrations

Application of semiquantitative proteomics techniques to the Maillard reaction

Proteomic tools-in particular, mass spectrometry (MS)-have advanced significantly in recent years, and the identification of proteins within complex mixtures is now a routine procedure. Quantitative methods of analysis are less well advanced and continue to develop. These include the use of stable isotope ratio approaches, isotopically labeled peptide standards, and nonlabeling methods. This paper summarizes the use of MS as a proteomics tool to identify and semiquantify proteins and their modified forms by using examples of relevance to the Maillard reaction. Finally, some challenges for the future are presented.

Analysis of hop acids by capillary electrophoresis

Micellar electrokinetic. chromatography (MEKC) was used to separate components of hop extracts. The separation of a sample of iso-alpha -acids by MEKC was better and faster than by an established HPLC method, giving <0.8 % RSD on migration times and 5-10% RSD on peak areas. MEKC was also successfully used to separate the oxidation products of the - and beta -acids and thus to monitor the stability of hop products containing them. Furthermore, MEKC distinguished among samples of reduced iso-alpha -acids (rho-, tetrahydro- and hexahydro- derivatives). (C) 2001 Elsevier Science Ltd. All rights reserved.

Superficialidad máxima. Superficie como posibilidad de sentido: imagen y síntoma

En estas páginas se pretende proponer un modo de entender lo visto siempre como adaptación inmanente, deseo y simbolización, esto es, entenderlo como imagen. Se hará conforme a un concepto de ‘superficie’ que prolonga la lectura que hiciera Didi-Huberman del concepto de imagen-síntoma de Aby Warburg, y se apoya en textos de teoría psicoanalítica de la mano de Jacques Lacan, en un intento no de arruinar la capacidad de hermenéutica del observador, sino de entender la búsqueda del sentido y de la esencia –del arte por ejemplo– como la investigación sobre un conflicto histórico de pérdidas, crisis y memoria. ‘Superficie’ en tanto que masa átona y sin sentido donde el ojo siempre visiona formas: ver superficie es que el ojo siempre adapte lo visto, deseando abrirlo visionariamente en su significado para recabar su verdad oculta, pero paradójicamente cerrándolo. Porque mirar imágenes supone siempre perder visión respecto de una supuesta totalidad en la que se darían todos los significados en todas sus ambigüedades y en todas sus posibilidades históricas, pérdida sólo decible en su retorno en tanto que resignificación traumática. Aquí postulamos que la ilusión será creer no que las apariencias son ilusorias, sino que más allá de ellas hay “más realidad”. Este planteamiento no sólo ratifica la posición del sujeto, inserto en una superficie/cuadro dada-a-ver, sino que descubre la brecha constitutiva que le rige y que es un “más en él” que él mismo.

Economic cost of age-related macular degeneration: a review of recent research

As the population of most developed countries ages so the prevalence of diseases such as age-related macular degeneration (AMD) are likely to increase. To facilitate planning and informed debate regarding making provisions for this disease it is important that we have a clear understanding of the economic impact of visual impairment associated with AMD. In this paper we assess the state of current knowledge based on a review of published evidence in scientific journals. Based on our assessment of the evidence we argue that the paucity of research studies on the subject and wide variation in estimates produced from the few studies available make it difficult to assess with confidence the likely average direct cost-of-illness associated with AMD. We further argue that significant gaps in our understanding of the costs of AMD (particularly in respect of indirect costs) also exist. Current research should be augmented by more comprehensive studies.

Transfer of resistance training to enhance rapid coordinated force production by older adults

The purpose of this study was to examine the capacity of resistance training to enhance the rapid and coordinated production of force by older people. Thirty adults (greater than or equal to 60 years) completed a visually guided aiming task that required the generation of isometric torque in 2 df about the elbow prior to and following a 4-week training period. Groups of six participants were allocated to two progressive ( 40 - 100% maximal voluntary contraction (MVC)) resistance-training (PRT) groups, to two constant low-load (10% MVC) training groups (CLO) and to one no-training control group. Training movements required the generation of either combined flexion and supination (FLESUP), or combined extension and supination (EXTSUP). In response to training, target acquisition times in the aiming task decreased for all groups; however, both the nature of the training load and the training movement influenced the pattern and magnitude of improvements (EXTSUP_ CLO: 36%, FLESUP_ PRT 26%, EXTSUP_ PRT 22%, FLESUP_ CLO 20%, CONTROL 15%). For one group that trained with progressively increasing loads, there arose a subsequent decrease in performance in one condition of the transfer task. For each group, these adaptations were accompanied by systematic changes in the coordination of muscles about the elbow joint, particularly the biceps brachii.

Absolute Calibration of Atomic Density Measurements by Laser-Induced Fluorescence Spectroscopy with Two-Photon Excitation (TALIF)

The two-photon resonances of atomic hydrogen (? = 2 × 205.1 nm), atomic nitrogen (? = 2 × 206.6 nm) and atomic oxygen (? = 2 × 225.6 nm) are investigated together with two selected transitions in krypton (? = 2×204.2 nm) and xenon (? = 2×225.5 nm). The natural lifetimes of the excited states, quenching coefficients for the most important collisions partners, and the relevant ratios of the two-photon excitation cross sections are measured. These data can be applied to provide a calibration for two-photon laser-induced fluorescence measurements based on comparisons with spectrally neighbouring noble gas resonances.

Performance evaluation of a zerovalent iron reactive barrier: Mineralogical characteristics

There is a limited amount of information about the effects of mineral precipitates and corrosion on the lifespan and long-term performance of in situ Fe° reactive barriers. The objectives of this paper are (1) to investigate mineral precipitates through an in situ permeable Fe° reactive barrier and (2) to examine the cementation and corrosion of Fe° filings in order to estimate the lifespan of this barrier. This field scale barrier (225' long x 2' wide x 31' deep) has been installed in order to remove uranium from contaminated groundwater at the Y-12 plant site, Oak Ridge, TN. According to XRD and SEM-EDX analysis of core samples recovered from the Fe° portion of the barrier, iron oxyhydroxides were found throughout, while aragonite, siderite, and FeS occurred predominantly in the shallow portion. Additionally, aragonite and FeS were present in up-gradient deeper zone where groundwater first enters the Fe° section of the barrier. After 15 months in the barrier, most of the Fe° filings in the core samples were loose, and a little corrosion of Fe° filings was observed in most of the barrier. However, larger amounts of corrosion (~10-150 µm thick corrosion rinds) occurred on cemented iron particles where groundwater first enters the barrier. Bicarbonate/ carbonate concentrations were high in this section of the barrier. Byproducts of this corrosion, iron oxyhydroxides, were the primary binding material in the cementation. Also, aragonite acted as a binding material to a lesser extent, while amorphous FeS occurred as coatings and infilings. Thin corrosion rinds (2-50 µm thick) were also found on the uncemented individual Fe° filings in the same area of the cementation. If corrosion continues, the estimated lifespan of Fe° filings in the more corroded sections is 5 to 10 years, while the Fe° filings in the rest of the barrier perhaps would last longer than 15 years. The mineral precipitates on the Fe° filing surfaces may hinder this corrosion but they may also decrease reactive surfaces. This research shows that precipitation will vary across a single reactive barrier and that greater corrosion and subsequent cementation of the filings may occur where groundwater first enters the Fe° section of the barrier.