Nilpotent classical mechanics: s-geometry

We introduce specific type of hyperbolic spaces. It is not a general linear covariant object, but of use in constructing nilpotent systems. In the present work necessary definitions and relevant properties of configuration and phase spaces are indicated. As a working example we use a D=2 isotropic harmonic oscillator.Comment: 8 pages, presented at QGIS, June 2006, Pragu

Forest landscape restoration in the drylands of Latin America

Forest Landscape Restoration (FLR) involves the ecological restoration of degraded forest landscapes, with the aim of benefiting both biodiversity and human well-being. We first identify four fundamental principles of FLR, based on previous definitions. We then critically evaluate the application of these principles in practice, based on the experience gained during an international, collaborative research project conducted in six dry forest landscapes of Latin America. Research highlighted the potential for FLR; tree species of high socioeconomic value were identified in all study areas, and strong dependence of local communities on forest resources was widely encountered, particularly for fuelwood. We demonstrated that FLR can be achieved through both passive and active restoration approaches, and can be cost-effective if the increased provision of ecosystem services is taken into account. These results therefore highlight the potential for FLR, and the positive contribution that it could make to sustainable development. However, we also encountered a number of challenges to FLR implementation, including the difficulty of achieving strong engagement in FLR activities among local stakeholders, lack of capacity for community-led initiatives, and the lack of an appropriate institutional and regulatory environment to support restoration activities. Successful implementation of FLR will require new collaborative alliances among stakeholders, empowerment and capacity building of local communities to enable them to fully engage with restoration activities, and an enabling public policy context to enable local people to be active participants in the decision making process. © 2012 by the author(s). Published here under license by the Resilience Alliance

Compression of aerodynamic databases using high-order singular value decomposition

A methodology based on high-order singular value decomposition is presented to compress multidimensional (with the various dimensions associated with both the spatial coordinates and parameter values) aerodynamic databases. The method is illustrated with a database containing computational fluid dynamics calculations of the outer flow around a wing, with two free parameters, the Mach number and the angle of attack. Comparison is made between the results of compressing just one flow snapshot (for fixed values of the parameters), compressing a one-parameter family of snapshots, and compressing the whole database. Several compressing strategies are also discussed that deal with (a) treating the flow variables separately or considering all flow variables at a time, (b) considering the whole flow domain simultaneously or dividing it into blocks, and (c) using various measures of errors. The main conclusion is that a large compression factor is generally obtained. Furthermore, the compression factor increases exponentially as the dimension of the database increases for any fixed error, namely the compression factor increases by an order of magnitude with each new database dimension for an error level of 1%

Diagnostic ability of multifocal electroretinogram in early multiple sclerosis using a new signal analysis method

Purpose To determine if a novel analysis method will increase the diagnostic value of the multifocal electroretinogram (mfERG) in diagnosing early-stage multiple sclerosis (MS). Methods We studied the mfERG signals of OD (Oculus Dexter) eyes of fifteen patients diagnosed with early-stage MS (in all cases < 12 months) and without a history of optic neuritis (ON) (F: M = 11:4), and those of six controls (F:M = 3:3). We obtained values of amplitude and latency of N1 and P1 waves, and a method to assess normalized root-mean-square error (FNRMSE) between model signals and mfERG recordings was used. Responses of each eye were analysed at a global level, and by rings, quadrants and hemispheres. AUC (area under the ROC curve) is used as discriminant factor. Results The standard method of analysis obtains further discrimination between controls and MS in ring R3 (AUC = 0.82), analysing N1 waves amplitudes. In all of the retina analysis regions, FNRMSE value shows a greater discriminating power than the standard method. The highest AUC value (AUC = 0.91) was in the superior temporal quadrant. Conclusion By analysing mfERG recordings and contrasting them with those of healthy controls it is possible to detect early-stage MS in patients without a previous history of ON

INTEGRACIÓN DE MODELOS FOTOVOLTAICO E HIDRÁULICO PARA LA MEJORA DE LA GESTIÓN DE BOMBEOS SOLARES DE INYECCIÓN DIRECTA A SISTEMAS DE RIEGO

[EN] The agricultural irrigaation systems spend big quantity of energy to extract wáter from groundwater or surface water and maintain the pressure demand in the irrigation subunits. At the moment, the high fossil fuels and energy prices moreover the deep concern by the emissions of CO2 have made that the solar water pumping have had an important impact because the solar energy is clean and renewable energy, easy installation and maintenance with a long service life and great reliability. In this study analyze the hydraulic model and photovoltaic model togheter used to managing the dripping irrigation by direct injection in almond fields of 90 ha that is fed by photovoltaic system to optimizing the pressure and flow rate in a different subunits. Moreover, another important thing is the uniformity of the system to know the quality of irrigation[ES] Los sistemas de riego en agricultura suponen una gran demanda de energía debido a las extracciones desde captaciones subterráneas o superficiales y a la aplicación de la presión necesaria en las subunidades de riego. Actualmente, los elevados precios en los combustibles fósiles y la energía junto a la preocupación por la reducción de las emisiones de CO2, han propiciado un importante avance en los sistemas de bombeo solar, siendo la energía solar fotovoltaica una energía limpia y renovable, de fácil instalación y mantenimiento, con una larga vida útil y una alta fiabilidad. En el desarrollo de este estudio se ha analizado de forma conjunta el modelo hidráulico y fotovoltaico creado para gestionar el riego por goteo en inyección directa de una plantación de almendro de 90 ha, alimentada con placas solares con el fin de optimizar los valores de presión y caudal necesarios en las diferentes subunidades de riego existentes. Además, se ha tenido en cuenta un aspecto clave como es la uniformidad de emisión para la determinación de la calidad del riego en la explotación.Cervera Gascó, J.; Del Castillo Sánchez Cañamares, A.; Montero Martinez, J.; Tarjuelo Martín-Benito, J.; Moreno Hidalgo, M. (2015). INTEGRACIÓN DE MODELOS FOTOVOLTAICO E HIDRÁULICO PARA LA MEJORA DE LA GESTIÓN DE BOMBEOS SOLARES DE INYECCIÓN DIRECTA A SISTEMAS DE RIEGO. En XXXIII CONGRESO NACIONAL DE RIEGOS. Valencia 16-18 junio de 2015. Editorial Universitat Politècnica de València. https://doi.org/10.4995/CNRiegos.2015.1520OC

A new approach to ascertain the sensitivity to water stress of different plant water indicators

[SPA] Se evaluó la sensibilidad al déficit hídrico de diferentes indicadores de estado hídrico del cultivo durante la poscosecha tardía de nectarinos extra-tempranos, en una finca comercial en la que se dispusieron dos tratamientos de riego: (i) Un control (TCTL), regado al 120 % de la evapotranspiración potencial de cultivo a fin de evitar condiciones limitantes de agua en el suelo y (II) un tratamiento de déficit hídrico (TD), regado al 50 % de TC. Los indicadores estudiados fueron: máxima contracción de tronco (MCD); tasa de crecimiento diario de tronco (TCD), potencial hídrico de tallo al mediodía (ΨT); conductancia estomática foliar (Gs); y fotosíntesis neta (Pn). Los mayores valores de intensidades de señal (SI) –ratio de los valores de TD y TCTL- se alcanzaron en TCD, Gs y Pn (2.6, 3, y 2.9, respectivamente), los valores de sensibilidad (S) –calculados como el ratio IS entre coeficiente de variación de las medidas (IS·CV-1)- fueron altos en ΨT y MCD (14 y 11.4, respectivamente), sin embargo sus coeficientes de variación fueron los menores (11 y 14 %, respectivamente). Se propone un nuevo enfoque (S*) para calcular la sensibilidad de los indicadores de estado hídrico de la planta, ya que el método tradicional puede generar altos valores de sensibilidad sin que se identifiquen diferencias entre tratamientos de riego. [ENG] The sensitivity to water stress of different plant water indicators was evaluated during the late postharvest period of extra-early nectarine trees growing in a commercial orchard and submitted to two irrigation treatments: (i) a control (TC), irrigated at 120% of crop evapotranspiration to avoid any soil water limitations, and (ii) a water deficit treatment (TD), irrigated at 50% of TC. The plant indicator studied were: the maximum daily trunk shrinkage (MCD); trunk growth rate (TCD); midday stem water potential (ΨT); leaf conductance (Gs); and net photosynthesis (Pn). Although the highest signal intensity (SI) values -the ratio of deficit irrigation treatment values to control values- were reached by TGR, Gs and Pn (2.6, 3 and 2.9, respectively), the sensitivity (S) values- calculated as the ratio of SI to coefficient of variation (SI·CV−1)- were higher in ΨT and MDS (14 and 11.4, respectively), since their CV values were the lowest (11 and 14%, respectively). A new approach (S*) is proposed to calculate the sensitivity of the plant water indicators, since the standard method can result in high sensitivity values without identifying differences between irrigation treatments.Este estudio fue subvencionado por el Ministerio Español de ciencia e innovación (AGL2010-19201-C04-04), y el proyecto europeo SIRRIMED (FP7-KBBE-2009-3-245159)

Efectos y seguridad del perfluorohexiloctano en la superficie ocular y el endotelio corneal

Objetivo Evaluar los efectos y la seguridad del perfluorohexiloctano (F6H8) tópico en la superficie ocular y el endotelio corneal. Métodos Fueron diagnosticados 45 pacientes (90 ojos) de enfermedad de ojo seco, se seleccionaron y se les prescribió tratamiento con F6H8 durante 6 meses. Las variables en la tinción corneal se documentaron usando la escala National Eye Institute/Industry Workshop (NEI), las variables conjuntivales usando la escala Oxford y los parámetros corneales, como el espesor corneal central, la densidad celular, el coeficiente de variación, la hexagonalidad y el área celular promedio, al inicio del estudio, a los 3 meses y a los 6 meses. Se evaluó también el cumplimiento y la satisfacción. Resultados El tratamiento con F6H8 redujo la tinción corneal promedio en pacientes cumplidores a una media de -0, 84 ± 1, 95 a los 3 meses (p = 0, 001) y a -1, 65 ± 2, 42 a los 6 meses (p < 0, 001). La tinción conjuntival a los 6 meses mostró una disminución promedio de -0, 13 (p = 0, 319). Los parámetros endoteliales no mostraron diferencia significativa, excepto el espesor corneal central, que mostró una disminución estadísticamente significativa (era de 545, 30 ± 32, 25 µm al comienzo del estudio y 538, 40 ± 31, 36 µm tras 6 meses, p = 0, 009). Al final del estudio, el 46% de los pacientes informaron sentirse subjetivamente mejor, el 40, 5% no sintió cambios y el 13, 5% se sintió subjetivamente peor. Conclusiones El tratamiento tópico con F6H8 para la enfermedad de ojo seco no alteró las variables medidas del endotelio corneal, aunque sí mostró mejoría en la tinción corneal y en la satisfacción. Objective: To evaluate the effects and safety of topical drops of perfluorohexyloctane (F6H8) on the ocular surface and the corneal endothelium. Methods: Forty-five patients (90 eyes) diagnosed with dry eye disease were recruited and prescribed treatment with F6H8 as part of a six-month prospective multicentre study. Variables in corneal staining were documented using the National Eye Institute/Industry Workshop scale. The conjunctival variables included using the Oxford scale, as well as corneal parameters, such as central corneal thickness, cell density, coefficient of variation, hexagonality, and mean cell area, at the start of the study, and at 3 months and 6 months. Compliance and satisfaction with the treatment were measured. Results: F6H8 drops reduced mean corneal staining based on the NEI scale in compliant patients to a mean of -0.84 ± 1.95 at 3 months (P=.001) and to -1.65 ± 2.42 at 6 months (P<.001). Conjunctival staining at 6 months showed a mean decrease of -0.13 (P=.319). The endothelial parameters did not show a significant difference, in contrast to the central corneal thickness that showed a statistically significant decrease (545.30 ± 32.25 at the start of the study to 538.40 ± 31.36 after 6 months, P=.009). At the end of the study, 46% of patients reported feeling subjectively better, 40.5% felt the same, and 13.5% felt subjectively worse. Conclusions: Topical treatment with F6H8 for dried eye disease did not alter the measured variables of the corneal endothelium, but showed improvement in corneal staining and satisfaction

Eyelid Disorders in Ophthalmology Practice: Results from a Large International Epidemiological Study in Eleven Countries

Purpose: Anecdotal evidence suggests that eyelid disorders are common, although estimates of prevalence vary. The current study determines the prevalence of eyelid disorders, meibomian gland dysfunction (MGD) and related diseases (specifically ocular surface disease) in a population of patients presenting for routine ophthalmologic consultations. Methods: This cross-sectional epidemiologic survey evaluated patients presenting for routine ophthalmic visits. During the consultation an ophthalmologist completed a questionnaire, and each patient underwent an ophthalmic examination and completed a quality of life questionnaire. Results: Three hundred forty-nine ophthalmologists, recruited from 11 countries, provided data on 6525 patients. Patients were predominantly females (61.6%). The mean age of the study population was 57.0 ± 17.6 years. Eyelid disorders were diagnosed in 5109 (78.3%) patients and were statistically associated with

Recommendations for ophthalmologic practice during the easing of COVID-19 control measures

In the context of the COVID-19 pandemic, this paper provides recommendations for medical eye care during the easing of control measures after lockdown. The guidelines presented are based on a literature review and consensus among all Spanish Ophthalmology Societies regarding protection measures recommended for the ophthalmologic care of patients with or without confirmed COVID-19 in outpatient, inpatient, emergency and surgery settings. We recommend that all measures be adapted to the circumstances and availability of personal protective equipment at each centre and also highlight the need to periodically update recommendations as we may need to readopt more restrictive measures depending on the local epidemiology of the virus. These guidelines are designed to avoid the transmission of SARS-CoV-2 among both patients and healthcare staff as we gradually return to normal medical practice, to prevent postoperative complications and try to reduce possible deficiencies in the diagnosis, treatment and follow-up of the ophthalmic diseases. With this update (5th) the Spanish Society of Ophthalmology is placed as one of the major ophthalmology societies providing periodic and systematized recommendations for ophthalmic care during the COVID-19 pandemic