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.

Indicadores de sostenibilidad ambiental en el periurbano de la ciudad de Mar del Plata, Argentina

Los indicadores de sostenibilidad conforman herramientas útiles para la toma de decisiones. Las ciudades latinoamericanas, y especialmente las áreas de expansión sin planificación adecuada, enfrentan desafíos cada vez mayores para revertir problemáticas que amenazan su sostenibilidad. El presente trabajo evalúa de manera preliminar, la sostenibilidad ambiental del periurbano de Mar del Plata (Argentina) tomando como referencia algunos de los indicadores propuestos por el modelo del Banco Interamericano de Desarrollo en la Iniciativa Ciudades Emergentes y Sostenibles. Se construyó un índice sintético (Índice de Sostenibilidad Ambiental, ISA) que integra trece indicadores agrupados en ocho temas. Las situaciones más críticas (ISA: 0,45-0,558) se identifican fundamentalmente en zonas en las que se desarrollan actividades rurales y en las que se localizan asentamientos de carácter precario. El estudio realizado profundiza en el conocimiento de la dimensión ambiental de la sostenibilidad, enfatizando en el análisis de los contrastes internos del periurbano marplatense.

On the complexity of the water-gas shift reaction mechanism over a Pt/CeO2 catalyst: Effect of the temperature on the reactivity of formate surface species studied by operando DRIFT during isotopic transient at chemical steady-state

The present report investigates the role of formate species as potential reaction intermediates for the WGS reaction (CO + H2O -> CO2 + H-2) over a Pt-CeO2 catalyst. A combination of operando techniques, i.e., in situ diffuse reflectance FT-IR (DRIFT) spectroscopy and mass spectrometry (MS) during steady-state isotopic transient kinetic analysis (SSITKA), was used to relate the exchange of the reaction product CO2 to that of surface formate species. The data presented here suggest that a switchover from a non-formate to a formate-based mechanism could take place over a very narrow temperature range (as low as 60 K) over our Pt-CeO2 catalyst. This observation clearly stresses the need to avoid extrapolating conclusions to the case of results obtained under even slightly different experimental conditions. The occurrence of a low-temperature mechanism, possibly redox or Mars van Krevelen-like, that deactivates above 473 K because of ceria over-reduction is suggested as a possible explanation for the switchover, similarly to the case of the CO-NO reaction over Cu, I'd and Rh-CeZrOx (see Kaspar and co-workers [1-3]). (c) 2006 Elsevier B.V. All rights reserved.

Liquid structure of the ionic liquid 1,3-dimethylimidazolium bis{(trifluoromethyl)sulfonyl}amide

Neutron diffraction has been used to determine the liquid structure of 1,3-dimethylimidazolium bis{( trifluoromethyl) sulfonyl} amide ([dmim][NTf2]). Significantly smaller charge ordering is found in this liquid compared with analogous chloride and hexafluorophosphate salts due to the diffuse charge density and size of the [NTf2](-) anion. This is manifested in a much larger cation-cation and cation-anion separation and an overlap of the cation-cation and cation-anion shells. Comparison of the liquid structure with the crystal structure reported by Holbrey et al. ( Dalton Trans. 2004, 2267) indicates little correlation, for example, the [NTf2](-) anion adopts a trans orientation predominantly in the liquid whereas a cis orientation is found in the solid phase.

Identifying an O-2 supply pathway in CO oxidation on Au/TiO2(110): A density functional theory study on the intrinsic role of water

Au catalysis has been one of the hottest topics in chemistry in the last 10 years or so. How O-2 is supplied and what role water plays in CO oxidation are the two challenging issues in the field at the moment. In this study, using density functional theory we show that these two issues are in fact related to each other. The following observations are revealed: (i) water that can dissociate readily into OH groups can facilitate O-2 adsorption on TiO2; (ii) the effect of OH group on the O-2 adsorption is surprisingly long-ranged; and (iii) O-2 can also diffuse along the channel of Ti (5c) atoms on TiO2(1 10), and this may well be the rate-limiting step for the CO oxidation. We provide direct evidence that O-2 is supplied by O-2 adsorption on TiO2 in the presence of OH and can diffuse to the interface of Au/TiO2 to participate in CO oxidation. Furthermore, the physical origin of the water effects on Au catalysis has been identified by electronic structure analyses: There is a charge transfer from TiO2 in the presence of OH to O-2, and the O-2 adsorption energy depends linearly on the 02 charge. These results are of importance to understand water effects in general in heterogeneous catalysis.

Hematopoietic malignancies associated with viral and alcoholic hepatitis

Hepatitis C virus (HCV) and hepatitis B virus (HBV) have been associated with hematopoietic malignancies, but data for many subtypes are limited. From the U.S. Surveillance, Epidemiology, and End Results-Medicare database, we selected 61,464 cases (=67 years) with hematopoietic malignancies and 122,531 population-based controls, frequency-matched by gender, age, and year (1993-2002). Logistic regression was used to compare the prevalence of HCV, HBV, and alcoholic hepatitis in cases and controls, adjusted for matching factors, race, duration of Medicare coverage, and number of physician claims. HCV, HBV, and alcoholic hepatitis were reported in 195 (0.3%), 111 (0.2%), and 404 (0.7%) cases and 264 (0.2%), 242 (0.2%), and 798 (0.7%) controls, respectively. HCV was associated with increased risk of diffuse large B-cell lymphoma [odds ratio (OR) 1.52, 95% confidence interval (95% CI) 1.05-2.18], Burkitt lymphoma (OR 5.21, 95% CI 1.62-16.8), follicular lymphoma (OR 1.88, 95% CI 1.17-3.02), marginal zone lymphoma (OR 2.20, 95% CI 1.22-3.95), and acute myeloid leukemia (OR 1.54, 95% CI 1.00-2.37). In contrast, HBV was unrelated to any hematopoietic malignancies. Alcoholic hepatitis was associated with decreased risk of non-Hodgkin lymphoma overall, but increased risk of Burkitt lymphoma. In summary, HCV, but not other causes of hepatitis, was associated with the elevated risk of non-Hodgkin lymphoma and acute myeloid leukemia. HCV may induce lymphoproliferative malignancies through chronic immune stimulation. Copyright © 2008 American Association for Cancer Research.


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Abnormal Functional Connectivity of Hippocampus During Episodic Memory Retrieval Processing Network in Amnestic Mild Cognitive Impairment.

BACKGROUND: Functional connectivity magnetic resonance imaging technique has revealed the importance of distributed network structures in higher cognitive processes in the human brain. The hippocampus has a key role in a distributed network supporting memory encoding and retrieval. Hippocampal dysfunction is a recurrent finding in memory disorders of aging such as amnestic mild cognitive impairment (aMCI) in which learning- and memory-related cognitive abilities are the predominant impairment. The functional connectivity method provides a novel approach in our attempts to better understand the changes occurring in this structure in aMCI patients. METHODS: Functional connectivity analysis was used to examine episodic memory retrieval networks in vivo in twenty 28 aMCI patients and 23 well-matched control subjects, specifically between the hippocampal structures and other brain regions. RESULTS: Compared with control subjects, aMCI patients showed significantly lower hippocampus functional connectivity in a network involving prefrontal lobe, temporal lobe, parietal lobe, and cerebellum, and higher functional connectivity to more diffuse areas of the brain than normal aging control subjects. In addition, those regions associated with increased functional connectivity with the hippocampus demonstrated a significantly negative correlation to episodic memory performance. CONCLUSIONS: aMCI patients displayed altered patterns of functional connectivity during memory retrieval. The degree of this disturbance appears to be related to level of impairment of processes involved in memory function. Because aMCI is a putative prodromal syndrome to Alzheimer's disease (AD), these early changes in functional connectivity involving the hippocampus may yield important new data to predict whether a patient will eventually develop AD.

Formation of Ammonia during the NO-H-2 Reaction over Pt/ZrO2

The mechanism for the formation of NH3 during the NO-H-2 reaction over Pt/ZrO2 was studied. Steady-state isotopic transient kinetic analysis was carried out with isotopic switching from (NO)-N-15-D-2 to (NO)-N-14-D-2, and the results revealed that formation of N-2 and N2O was associated with linearly adsorbed NO on the Pt surface, whereas ammonia formation was associated with NDx species adsorbed on ZrO2. The adsorbed NHx species were not observed on the surface of ZrO2 during NH3 adsorption. From transient kinetic experiments, the formation rates of NHx species and of gaseous NH3 agreed with each other, suggesting that the NHx species on ZrO2 was an ammonia intermediate. The NDx species did not react with D-2 directly, but H-D exchange occurred easily. The addition of H2O to the NO-H-2 feed gas enhanced the formation of NH3. In situ diffuse reflectance spectra and transient kinetic analysis revealed that H2O enhanced the conversion of NHx species to NH3.

Turbulent diffusion and mixing in interstellar dark clouds with adsorption onto grains

This paper reports the results of models of dark cloud chemistry incorporating a depth dependent density distribution with diffusive mixing and adsorption onto grains. The model is based on the approach taken by Xie et al. (1995), with the addition of grain accretion effects. Without diffusion, the central regions of the cloud freeze out in less than 10(7) years. Freeze-out time is dependent on density, so the diffuse outer region of the cloud remains abundant in gas for about an order of magnitude longer. We find that fairly small amounts of diffusive mixing can delay freeze-out at the centre of the model cloud for a time up to an order of magnitude greater than without diffusion, due to material diffusing inward from the edges of the cloud. The gas-phase lifetime of the cloud core can thus be increased by up to an order of magnitude or more by this process. We have run three different grain models with various diffusion coefficients to investigate the effects of changing the sticking parameters.

Troubled Geographies: A Spatial History of Religion and Society in Ireland

Ireland’s landscape is marked by fault lines of religious, ethnic, and political identity that have shaped its troubled history. Troubled Geographies maps this history by detailing the patterns of change in Ireland from 16th century attempts to “plant” areas of Ireland with loyal English Protestants to defend against threats posed by indigenous Catholics, through the violence of the latter part of the 20th century and the rise of the “Celtic Tiger.” The book is concerned with how a geography laid down in the 16th and 17th centuries led to an amalgam based on religious belief, ethnic/national identity, and political conviction that continues to shape the geographies of modern Ireland. Troubled Geographies shows how changes in religious affiliation, identity, and territoriality have impacted Irish society during this period. It explores the response of society in general and religion in particular to major cultural shocks such as the Famine and to long term processes such as urbanization.

Zur kognitiven Konstruktion von (Un-)Gerechtigkeit militärischer Gewalt: Die moralische Beurteilung des Kosovo-Kriegs

With reference to the Kosovo war, we examined how the (un-)justness of military intervention is cognitively constructed. Four types of reinterpretation were hypothesized to relate to positive evaluation of the intervention: minimisation of negative consequences of NATO's intervention, denial of responsibility of the Western countries for the war, blame of Yugoslavia, and justification of the intervention through positive motives. As determinants of evaluation of the war, belief in a just world, militarism-pacifism, authoritarianism, and diffuse political support were taken into account. Hypotheses were tested with 165 university students using structural equation modelling. Consistent with our assumptions, the four types of reinterpretation related strongly to positive evaluation of the intervention, showing their relevance with regard to military intervention. Further, the assessed political attitudes influenced evaluation of the war while, contrary to predictions, belief in a just world did not. The causal status of the reinterpretations and the interplay of belief in a just world and political attitudes are discussed.

Resolution of a taxonomic conundrum: an ultrastructural and molecular description of the life cycle of Pleistophora mulleri (Pfeiffer 1895; Georgevitch 1929)

The classification of a microsporidian parasite observed in the abdominal muscles of amphipod hosts has been repeatedly revised but still remains inconclusive. This parasite has variable spore numbers within a sporophorous vesicle and has been assigned to the genera Glugea, Pleistophora, Stempellia, and Thelohania. We used electron microscopy and molecular evidence to resolve the previous taxonomic confusion and confirm its identification as Pleistophora mulleri. The life cycle of P. mulleri is described from the freshwater amphipod host Gammarus duebeni celticus. Infection appeared as white tubular masses within the abdominal muscle of the host. Light and transmission electron microscope examination revealed the presence of an active microsporidian infection that was diffuse within the muscle block with no evidence of xenoma formation. Paucinucleate merogonial plasmodia were surrounded by an amorphous coat immediately external to the plasmalemma. The amorphous coat developed into a merontogenetic sporophorous vesicle that was present throughout sporulation. Sporogony was polysporous resulting in uninucleate spores, with a bipartite polaroplast, an anisofilar polar filament and a large posterior vacuole. SSU rDNA analysis supported the ultrastructural evidence clearly placing this parasite within the genus Pleistophora. This paper indicates that Pleistophora species are not restricted to vertebrate hosts.

Factors influencing eating a varied diet in old age

OBJECTIVE:
To investigate the influences of resources and food-related goals on the variety of food choice among older people.
DESIGN:
A questionnaire-based survey in eight European countries: Poland, Portugal, United Kingdom, Germany, Sweden, Denmark, Italy and Spain.
SUBJECTS:
Participants (n 3200) were above 65 years of age and living in their own homes. The samples were quota samples, eight groups of fifty in each country, based on gender, age and living circumstances, reflecting the diversity of each of the national populations based on education, income and urbanization of living environment.
RESULTS:
Hierarchical multiple regression analysis showed that income, health status, access to a car and living arrangement affected the level of dietary variety. The perceived level of different food-related resources impacted the consumption of a varied diet over and above actual resource levels. Food-related goals contributed to variety of food intake that was not accounted for by the amount of material resources possessed or the social and other resources perceived to be possessed.
CONCLUSIONS:
Older people's variety of food intake depended on material resources (e.g. monthly income, access to a car, living arrangement, physical and mental health). However, in addition to these variables, the way older people perceived other resources, such as their level of appetite, their food knowledge, their perception of the distance to the shops, access to high-quality products, having better kitchen facilities, access to good service providers and support from friends and neighbours, all contributed to how varied a diet they ate.

Synthesis, Structure, and Spectroscopic Properties of the New Lanthanum(III) Fluoride Oxomolybdate(VI) La3FMo4O16

La3FMo4O16 crystallizes in the triclinic crystal system with space group P (1) over bar [a = 724.86(2) pm, b = 742.26(2) pm, c = 1469.59(3) pm, a = 101.683(2)degrees, beta 102.118(2)degrees, gamma = 100.279(2)degrees] with two formula units per unit cell. The three crystallographically independent La3+ cations show a coordination number of nine each, with one F- and eight O2- anions forming distorted monocapped square antiprisms. The fluoride anion is coordinated by all three lanthanum cations to form a nearly planar triangle. Besides three crystallographically independent tetrahedral [MoO4](2-) units, a fourth one with a higher coordination number (CN = 4 +1) can be found in the crystal structure, forming a dimeric entity with a formula of [Mo2O8](4-) consisting of two edge-connected square pyramids. Several spectroscopic measurements were performed on the title compound, such as infrared, Raman, and diffuse reflectance spectroscopy. Furthermore, La3FMo4O16 was investigated for its capacity to work as host material for doping with luminescent active cations, such as Ce3+ or Pr3+. Therefore, luminescence spectroscopic as well as EPR measurements were performed with doped samples of the title compound. Both the pure and the doped compounds can be synthesized by fusing La2O3, LaF3 and MoO3 (ratio 4:1:12; ca. 1 % CeF3 and PrF3 as dopant, respectively) in evacuated silica ampoules at 850 degrees C for 7 d.