Quantitative estimation of vegetation traits and temporal dynamics using 3-D radiative transfer models, high-resolution hyperspectral images and satellite imagery

Large-scale monitoring of vegetation dynamics by remote sensing is key to detecting early signs of vegetation decline. Spectral-based indicators of phys-iological plant traits (PTs) have the potential to quantify variations in pho-tosynthetic pigments, chlorophyll fluorescence emission, and structural changes of vegetation as a function of stress. However, the specific response of PTs to disease-induced decline in heterogeneous canopies remains largely unknown, which is critical for the early detection of irreversible damage at different scales. Four specific objectives were defined in this research: i) to assess the feasibility of modelling the incidence and severity of Phytophthora cinnamomi and Xylella fastidiosa based on PTs and biophysical properties of vegetation; ii) to assess non-visual early indicators, iii) to retrieve PT using radiative transfer models (RTM), high-resolution imagery and satellite observations; and iv) to establish the basis for scaling up PTs at different spatial resolutions using RTM for their retrieval in different vegetation co-vers. This thesis integrates different approaches combining field data, air- and space-borne imagery, and physical and empirical models that allow the retrieval of indicators and the evaluation of each component’s contribution to understanding temporal variations of disease-induced symptoms in heter-ogeneous canopies. Furthermore, the effects associated with the understory are introduced, showing not only their impact but also providing a compre-hensive model to account for it. Consequently, a new methodology has been established to detect vegetation health processes and the influence of biotic and abiotic factors, considering different components of the canopy and their impact on the aggregated signal. It is expected that, using the presented methods, existing remote sensors and future developments, the ability to detect and assess vegetation health globally will have a substantial impact not only on socio-economic factors, but also on the preservation of our eco-system as a whole

Costs and salaries in cheap “lvdi” organized in Western Roman Empire

Las inscripciones nos informan de la edición en las ciudades provinciales de “ludi” modestos por valor de menos de 1.000 HS/día, coste muy lejano de los fastuosos espectáculos organizados en Roma y en las capitales provinciales. Con ese dinero el editor debía pagar a los profesionales que intervenían, el atrezzo necesario (vestuario, caballos de carreras, etc.) y el acondicionamiento del escenario. Dado el escaso valor de los “ludi” modestos, el salario de los actores, aurigas y púgiles rondaría los 5 HS/actuación, y para las gradas y el escenario o para el alquiler de los caballos apenas se podrían destinar unos pocos cientos de sestercios.According to some inscriptions, in the provincial towns there were modest “ludi” cheaper than 1,000 HS per day. This cost is very lower than the cost of the splendid shows organized in Rome and in provincial capitals. With this monetary quantity the editor should pay for the professionals, the necessary attrezo (dresses, race horses and so on) and the fitting out stage. Because of the low value of the modest “ludi”, the salary of the actors, charioteers and boxers would be around 5 HS/ performance, and the cost of the stand and the stage or the rent of race horses would be hardly a few hundred sesterces

La nominación de los espectáculos romanos en la epigrafía provincial del Occidente latino

279 shows are recorded in 234 Latin inscriptions, from high-imperial cronology and from West Provinces, excluding Italia. The aim of this article is to establish which Latin formulas are used for the nomination of the spectacles. Five types of spectacles are organized mainly: munus gladiatorum, uenatio, ludi scaenici, circenses y certamina pugilum.Existen 279 espectáculos mencionados en 234 inscripciones latinas, de cronología altoimperial, que provienen de las provincias del Occidente romano, excluida Italia. El objetivo de este artículo es establecer qué fórmulas latinas se utilizan para nominar la edición de los diferentes espectáculos. Se organizaban principalmente cinco tipos de espectáculos: munus gladiatorum, uenatio, ludi scaenici, circenses y certamina pugilum

El coste de los espectáculos gladiatorios en las ciudades del Occidente romano

The aim of this paper is to explore the daily cost of munera gladiatorum in the towns of the Roman Occident and to classify it in three levels of prices through the analysis of the inscriptions which commemorate gladiatorial combats and of the imperial laws, especially the oratio de pretiis gladiatorum minuendis.En este artículo intentamos aproximarnos al coste diario de los munera gladiatorum en las ciudades del Occidente romano, clasificándolo en tres niveles de precios, a través del análisis de las inscripciones que conmemoran la edición de gladiadores y de la legislación imperial, especialmente la oratio de pretiis gladiatorum minuendis

Understanding the temporal dimension of the red-edge spectral region for forest decline detection using high-resolution hyperspectral and Sentinel-2a imagery

The operational monitoring of forest decline requires the development of remote sensing methods that are sensitive to the spatiotemporal variations of pigment degradation and canopy defoliation. In this context, the red-edge spectral region (RESR) was proposed in the past due to its combined sensitivity to chlorophyll content and leaf area variation. In this study, the temporal dimension of the RESR was evaluated as a function of forest decline using a radiative transfer method with the PROSPECT and 3D FLIGHT models. These models were used to generate synthetic pine stands simulating decline and recovery processes over time and explore the temporal rate of change of the red-edge chlorophyll index (CI) as compared to the trajectories obtained for the structure-related Normalized Difference Vegetation Index (NDVI). The temporal trend method proposed here consisted of using synthetic spectra to calculate the theoretical boundaries of the subspace for healthy and declining pine trees in the temporal domain, defined by CItime=n/CItime=n+1 vs. NDVItime=n/NDVItime=n+1. Within these boundaries, trees undergoing decline and recovery processes showed different trajectories through this subspace. The method was then validated using three high-resolution airborne hyperspectral images acquired at 40 cm resolution and 260 spectral bands of 6.5 nm full-width half-maximum (FWHM) over a forest with widespread tree decline, along with field-based monitoring of chlorosis and defoliation (i.e., ‘decline’ status) in 663 trees between the years 2015 and 2016. The temporal rate of change of chlorophyll vs. structural indices, based on reflectance spectra extracted from the hyperspectral images, was different for trees undergoing decline, and aligned towards the decline baseline established using the radiative transfer models. By contrast, healthy trees over time aligned towards the theoretically obtained healthy baseline. The applicability of this temporal trend method to the red-edge bands of the MultiSpectral Imager (MSI) instrument on board Sentinel-2a for operational forest status monitoring was also explored by comparing the temporal rate of change of the Sentinel-2-derived CI over areas with declining and healthy trees. Results demonstrated that the Sentinel-2a red-edge region was sensitive to the temporal dimension of forest condition, as the relationships obtained for pixels in healthy condition deviated from those of pixels undergoing decline.JRC.D.1-Bio-econom

Analysis of Magnetoencephalography Signals from Alzheimer’s Disease Patients Using Granger Causality

Producción CientíficaThe aim of this study was to analyze resting-state magnetoencephalography (MEG) activity in Alzheimer’s disease (AD) by means of Granger Causality (GC), an effective connectivity measure that provides an estimation of the information flow between brain regions. For this task, five minutes of MEG recordings were acquired with a 148-channel whole-head magnetometer from 36 AD patients and 26 healthy controls. Abnormalities in AD connectivity were found in the five typical frequency bands: delta (δ, 1-4 Hz), theta (θ, 4-8 Hz), alpha (α, 8-13 Hz), beta (β, 13-30 Hz), and gamma (γ, 30-65 Hz). Noteworthy increments in delta band and decrements in beta and gamma bands revealed disrupted connections in AD brain activity. Our analyses suggest that GC may be useful to characterize the brain impairment in AD.Ministerio de Economía y Competitividad (TEC2014-53196-R)Junta de Castilla y León (VA059U13 y BIO/VA08/15

MEG analysis of neural dynamics in attention-deficit/hyperactivity disorder with fuzzy entropy

Producción CientíficaThe aim of this study was to analyze the neural dynamics in attention-deficit/hyperactivity disorder (ADHD). For this purpose, magnetoencephalographic (MEG) background activity was analyzed using fuzzy entropy (FuzzyEn), an entropy measure that quantifies signal irregularity, in 13 ADHD patients and 14 control children. Additionally, relative power (RP) was computed in conventional frequency bands (delta, theta, alpha, beta and gamma). FuzzyEn results showed that MEG activity was more regular in ADHD patients than in controls. Moreover, we found an increase of power in delta band and a decrease in the remaining frequency bands. Statistically significant differences (p-values <0.05; nonparametric permutation test for multiple comparisons) were detected for FuzzyEn in the posterior and left temporal regions, and for RP in the posterior, anterior and left temporal regions. Our results support the hypothesis that ADHD involves widespread functional brain abnormalities, affecting more areas than fronto-striatal circuits, such as the left temporal and posterior regions.Ministerio de Economía y Competitividad (project TEC2011-22987)Junta de Castilla y León (project BIO/VA38/14 and project VA059U13