Special cantilever geometry for the access of higher oscillation modes in atomic force microscopy

Employing higher oscillation modes of microcantilevers promises higher sensitivity when applied as sensors, for example, for mass detection or in atomic force microscopy. Introducing a special cantilever geometry, we show that the relation between the resonance frequencies of the first and second resonance modes can be modified to separate them further or to bring them closer together. In atomic force microscopy the latter is of special interest as the photodiode of the beam deflection detection limits the accessible frequency range. Using finite element simulations, we optimized the design of the modified cantilever geometry for a maximum reduction of the frequency of the second oscillation mode with respect to the first mode. Cantilevers were fabricated by silicon micromachining and subsequently utilized in an ultrahigh vacuum Kelvin probe force microscope imaging the surface potential of C60 on graphit

Heterogeneity in irrigators’ wtp and wta for water reliability

This paper is focused on the valuation of irrigation water supply reliability. We assess WTP and WTA for improvements and worsenings in irrigation water supply reliability, checking for the first time the disparity between average WTA and average WTP for this attribute of irrigation water supply. This assessment relies on a field experiment among farmers in an irrigated area located in southern Spain that is suffering a serious deterioration of water supply reliability because of climate change. Results obtained show average WTP estimates for moderate and significant improvements are €16.5 and €18.5/ha/year, respectively, while the average WTA estimates for moderate and significant worsenings are €765.6 and €881.1/ha/year. This indicates a very high WTA/WTP ratio of 46.4 and 47.6 for moderate and significant changes, much higher than those obtained in previous studies. Possible reasons which may explain such a disparity include reasons within neoclassical economic theory and endowment effects

RENTABILIDAD DE LA REPRODUCIÓN DE ENEMIGOS NATURALES DE ÁCAROS DEL PAPAYO (Carica papaya L.)

The papaya tree production in the central zone of the state of Veracruz, México, under intensive management, is highly profitable. The crop presents high populations of spider mites, commonly controlled with acaricides. However, this practice contaminates the environment, leaves residues in the fruit, causes poisoning of applicators and promotes the fast development of resistance to pest-control substances in the acari. An effective biological control of the pest can be achieved with predatory mites, massively produced. Therefore, the technical and economic viability of establishing a Center forMassive Reproduction of Phytoseiulus persimilis in the central area of Veracruz was evaluated. The internal rate of return (IRR), the net presen value (NPV) and the benefit/cost (B/C) were calculated in a horizon of five years, with three variations of price of the product per hectare: (MX) $1,000,$1,250 and $1,500. The opinion of producers was requested through a survey regarding the product that the Center would generate. The project shows acceptable profitability, with IRR values of 41.5, 115.6 and 187.2$411,368, $1’633,913 and$2’837,815, for the three prices of the product; and B/C relation of 1.01 in the first year with the lowest price of the product, up to 1.83 with the highest price obtained on the fifth year. The main competition in the region is the sale of acaricides such as dicofol, abamectin, fenbutatin oxide and imidacloprid. Of the producers, 61.4 % are willing to use predatory mites at a cost of $1,000 per hectare. As this product cannot be stored for long periods, the success lies in a production coordinated with groups of producers.La producción de papayo en la zona Centro del estado de Veracruz, México bajo manejo intensivo es altamente rentable. El cultivo presenta altas poblaciones de ácaros plaga, controladas comúnmente con acaricidas. Sin embargo, esta práctica contamina el ambiente, deja residuos en la fruta, intoxica a los aplicadores y promueve el rápido desarrollo de la resistencia a plaguicidas en los ácaros. Se puede lograr un control biológico efectivo de la plaga con ácaros depredadores, pero para lograrlo estos se deben producir masivamente. Por ello se evaluó la viabilidad técnica y económica de establecer un Centro de Reproducción Masiva de Phytoseiulus persimilis en la zona Centro de Veracruz. Se calculó la tasa interna de rentabilidad (TIR), el valor actual neto (VAN) y el beneficio/costo (B/C) en un horizonte de cinco años, con tres variaciones de precio del producto por hectárea: (MX)$1,000, $1,250 y$1,500. Se solicitó la opinión de los productores mediante una encuesta respecto al producto que generaría el Centro. El proyecto muestra rentabilidad aceptable, con valores de TIR de 41.5, 115.6 y 187.2 %; una VAN de $411,368,$1’633,913 y $2’837,815, para los tres precios del producto; y relación B/C de 1.01 en el primer año con el precio más bajo de producto, hasta 1.83 con el precio más alto obtenido en el quinto año. La principal competencia en la región es la venta de acaricidas como dicofol, abamectina, óxido de fembutatín e imidacloprid. El 61.4$1,000 por hectárea. Debido a que este producto no puede ser almacenado por largos períodos, el éxito depende de una producción coordinada con grupos de productores

INSECTICIDAS EN LA TRANSMISIÓN DEL VIRUS DE LA MANCHA ANULAR DE Carica papaya L., MEDIANTE Aphis nerii (Boyer de Fonscolombe)

The papaya ringspot virus (PRSV-p) is transmitted in a non-persistent way by females of Aphis nerii and other aphid species (Hemiptera: Aphididae). The effectiveness of the application of insecticides to reduce viral transmission has been questioned. Viral transmission tests have been performed with adult females of A. nerii in the laboratory, on papaya plants (Carica papaya). One, two, five and ten winged and wingless female adults of A. nerii were used. The presence of the PRSV-p was determined through the ELISA test. The effect of six insecticides/acaricides with different modes of action was evaluated (malathion, deltamethrin, imidacloprid, fenbutatin oxide, pymetrozine and rotenone), on the viral transmission and mortality of aphids. The products formulated were applied at the lowest recommended dose; later, they to papaya trees were exposed to the inoculating aphids for 24 h. The phytotoxicity was recorded visually in the laboratory. No significant differences were found (p<0.05) in the viral transmission between winged or wingless aphids. The greatest transmission (75 % to 80 %) was obtained with 10 adults and the lowest (15 % to 20 %) with one adult. The significantly lowest transmissions were obtained by using pymetrozine (19 %) and rotenone (29 %), while the highest were with deltamethrin (81 %) and malathion (66 %). Imidacloprid and malathion caused 100 % mortality at 24 h, while pymetrozine and fenbutatin oxide produced the lowest mortality (46 %). Rotenone caused phytotoxicity in papaya leaves. Pymetrozine has potential in the prevention of non-persistent viral transmission.El virus de la mancha anular del papayo (PRSV-p) es transmitido de forma no-persistente por hembras de Aphis nerii y otras especies de áfidos (Hemiptera: Aphididae). Se ha cuestionado la efectividad de la aplicación de insecticidas para reducir la transmisión viral. Se realizaron pruebas de transmisión viral con hembras adultas de A. nerii en laboratorio, sobre plantas de papayo (Carica papaya). Se utilizaron 1, 2, 5 y 10 hembras adultas aladas y ápteras de A. nerii. Se determinó la presencia del PRSV-p mediante la prueba de ELISA. Se evaluó el efecto de seis insecticidas/acaricidas con diferentes modos de acción (malatión, deltametrina, imidacloprid, óxido de fenbutatín, pymetrozine y rotenona), en la transmisión viral y mortalidad de áfidos. Los productos formulados se aplicaron a plantas de papayo a las dosis más bajas recomendadas; posteriormente se expusieron a los áfidos inoculativos por 24 h. La fitotoxicidad se registró visualmente en laboratorio. No presentaron diferencias significativas (p<0.05) en la transmisión viral entre áfidos alados o ápteros. La mayor transmisión (75% a 80%) se obtuvo con 10 adultos y la menor (15% a 20%) con un adulto. Las transmisiones significativamente más bajas se obtuvieron al usar pymetrozine (19%) y rotenona (29%), mientras que las mayores fueron con deltametrina (81%) y malatión (66%). El imidacloprid y malatión ocasionaron 100% de mortalidad a 24 h, mientras pymetrozine y óxido de fenbutatín produjeron la mortalidad más baja (46%). Rotenona ocasionó fitotoxicidad en hojas de papaya. Pymetrozine tiene potencial en la prevención de transmisión viral nopersistente

Factors influencing farmers’ adoption of ecological reconversion agri-environmental schemes in mountain olive groves

Mountain olive groves are characterized by low profitability, mainly due to their location in high steep-slope areas with poor, shallow soils. Consequently, they present a high risk of abandonment of the productive activity, which would be eventually associated with high potential environmental and socio-cultural losses. As an alternative, an ecological reconversion scheme is proposed to increase the provision of ecosystem services from this agroecosystem while reducing the socio-economic impacts related to the abandonment. Two alternative schemes are proposed, which differ in the possibility or not of harvesting the olive production. A double-bounded contingent valuation exercise is used in a sample of Andalusian mountain olive growers to assess their willingness to accept (WTA) for participating in these schemes, using a difference-in-utility model with a linear utility function with correlation between the participation choices in the two schemes as econometric specification. The results show high levels of mean WTA, higher for the scheme precluding harvesting, indicating that higher levels of payment are needed to get some acceptance from farmers. Results also show that structural (e.g., yield) and attitudinal factors (e.g., opinion about setting-aside low productivity olive groves for environmental reasons), among others, significantly influence farmers’ WTA for these schemes

The design of agri-environmental schemes: Farmers preferences in southern Spain

Agri-environmental schemes (AES) play a key role in promoting the production of environmental public goods by European Union agriculture. Although extensive literature has analyzed AES, some important issues remain understudied. This paper performs an ex-ante assessment of AES in permanent cropping, analyzing several issues that have received little attention from researchers, such as ecological focus areas (EFA) and collective participation. For this purpose, a choice experiment was used to assess farmers&rsquo; preferences towards AES in a case study of olive groves in southern Spain. Results show high heterogeneity among farmers, with different classes being identified, from potential participants to non-participants. As regards EFA, almost half of the farmers would be willing to accept it for low monetary incentives (&euro;8-9/ha per additional 1% of the farmland devoted to EFA) while the rest would do it for moderate-to-high monetary incentives (&euro;41-151/ha per additional 1% of EFA). However, for a high share of EFA (e.g., 5-7%) higher incentives would presumably be required due to the intrinsic spatial restrictions of olive groves. With regard to collective participation, we find that it is unlikely that farmers would participate collectively with the incentive of the up-to-30% EU-wide bonus. These results are relevant for policy-making now when new AES are being designed for the next programming period 2014-2020.Los programas medioambientales son un instrumento clave para la provisi&oacute;n de bienes p&uacute;blicos de car&aacute;cter ambiental. En este trabajo utilizando los experimentos de elecci&oacute;n se determina el grado de adopci&oacute;n seg&uacute;n el tipo de sistema de olivar. Los resultados indican que casi la mitad de los olivareros estar&iacute;an dispuestos a dedicar el 2% a Superficie de Inter&eacute;s Ecol&oacute;gico (SIE) por reducidos incentivos monetarios. Para una adopci&oacute;n entre 5-7% se requerir&iacute;an elevados incentivos.</p

Luxación posterior bilateral de la articulación escapulohumeral

Se presenta un caso de un hombre de 51 años, que tras sufrir una crisis convulsiva presentó dolor e impotencia funcional en ambos hombros. Tras realizar estudio radiográ- fico y TAC, se comprobó la existencia de una luxación escapulohumeral bilateral. El paciente fue tratado con reducción cerrada e inmovilización del miembro en abducción y rotación externa con un yeso toracobraquial.A case of bilateral posterior dislocation of the scapulo-humeral joint ocurring in a 51-year-old men after a convulsive attack is reported. Inmediately after convulsions, the patient refered pain and funtional disability in both shoulders and bilateral scapulo-humeral dislocation was confirmed by conventional radiograhips and CT-scan. Treatment consisted of closed reduction and inmobilization of the upper extremity in abduction and external rotation with a thoraco-braquial plaster cast

Biosorción de Cd (II) y Pb (II) de soluciones acousas en residuos agrícolas de Phaseolus vulgaris L.: optimización, cinética, isotermas y desorción

Industrial activities are the most common cause of water contamination by heavy metals, which endanger the quality of water resources and human health, due to their bioaccumulation capacity and consequent biomagnification. For this reason, the removal of metals from e uents before their discharge into the receiving water bodies is of crucial importance. This is why, in the present investigation, the biosorption processes of Cd (II) and Pb (II) in Phaseolus vulgaris L. (bean) agricultural residues (stems, leaves and leaf sheaths) were optimized. The influence of pH, biosorbent doses and initial concentration levels of metallic ions was evaluated using the response surface methodology (RSM). Quadratic models were developed for the percent removal of Cd (II) and Pb (II). Optimal biosorption conditions were attained at pH = 4.3, a 7.4 g/L biosorbent dose and an initial 9.14 mg/L concentration of each metal, achieving percent removals of 87.70 and 95.58% for Cd (II) and Pb (II), respectively. The FT-IR characterization showed that the functional groups involved in adsorption would be in the range of 2300 to 2400 cm-1. The biosorption kinetics were described by the pseudo first order model and the equilibrium data was adjusted to the Freundlich isotherm. An approximate desorption of 98% of Cd (II) and Pb (II) was achieved. The Phaseolus vulgaris L. residue showed a great biosorption capacity of Cd (II) and Pb (II) simultaneously.Las actividades industriales son la fuente más común de contaminación del agua por metales pesados que resultan ser un peligro para la calidad de los recursos hídricos y la salud humana, debido a su capacidad de bioacumulación y consecuente biomagnificación, por tal motivo, la remoción de metales de efluentes antes de ser vertidos a los cuerpos receptores es de crucial importancia. Razón por la cual, en la presente investigación se optimizó el proceso de biosorción de Cd (II) y Pb (II) en residuos agrícolas de Phaseolus vulgaris L. (frejol) que constó de tallos, hojas y vainas. Se evaluó la influencia del pH, dosis de biosorbente y concentración inicial del ion metálico mediante la metodología de superficie de respuesta (RSM). Se desarrollaron modelos cuadráticos para las remociones porcentuales de Cd (II) y Pb (II). Las condiciones óptimas de biosorción fueron pH=4.3, dosis de biosorbente 7.4 g/L y una concentración inicial de cada metal de 9.14 mg/L logrando remociones de 87.70 y 95.58% para Cd (II) y Pb (II), respectivamente. La caracterización por FT-IR mostró que, los grupos funcionales involucrados en la adsorción estarían en el rango de 2300 a 2400 cm-1. La cinética de biosorción fue descrita por el modelo de pseudo primer orden y los datos en equilibrio se ajustaron a la isoterma de Freundlich. Se logró una desorción aproximada de 98% de Cd (II) y Pb (II). El residuo de Phaseolus vulgaris L. mostró gran capacidad de biosorción de Cd (II) y Pb (II) simultáneamente.Campus Arequip

Placebo-controlled trial of nimodipine in the treatment of acute ischemic cerebral infarction

Nimodipine is a 1,4-dihydropyridine derivative that shows a preferential cerebrovascular activity in experimental animals. Clinical data suggest that nimodipine has a beneficial effect on the neurologic outcome of patients suffering an acute ischemic stroke. Our double-blind placebo-controlled multicenter trial was designed to assess the effects of oral nimodipine on the mortality rate and neurologic outcome of patients with an acute ischemic stroke. One hundred sixty-four patients were randomly allocated to receive either nimodipine tablets (30 mg q.i.d.) or identical placebo tablets for 28 days. Treatment was always started less than or equal to 48 hours after the acute event. The Mathew Scale, slightly modified by Gelmers et al, was used for neurologic assessment. Mortality rate and neurologic outcome after 28 days were used as evaluation criteria. We considered 123 patients to be valid for the analysis of efficacy. Mortality rates did not differ significantly between groups. Neurologic outcome after 28 days of therapy did not differ between groups. However, when only those patients most likely to benefit from any intervention (Mathew Scale sum score of less than or equal to 65 at baseline) were analyzed separately in post hoc-defined subgroups, the nimodipine-treated subgroups showed a significantly better neurologic outcome. This result suggests that some patients with acute ischemic stroke will benefit from treatment with nimodipine tablets