THE SPECTRAL CONTRIBUTION OF CAROTENOIDS TO LIGHT ABSORPTION AND REFLECTANCE IN GREEN LEAVES

Absorbance and reflectance spectra in the visible and near infrared range of the spectrum, acquired for maple (Acer platanoides L.) leaves were studied. Standard deviation of absorbance spectra showed that in yellow to green leaves, with chlorophyll content at least up to 30 nmol/cm2, there is a spectral feature at 520 nm attributable to carotenoids. Reflectance around 520 nm also correlates closely with carotenoids content in yellow to green leaves. Thus, this spectral feature at 520 nm could be used as a measure of carotenoids content in green leaves and plants

Thermal-based modeling of coupled carbon, water, and energy fluxes using nominal light use efficiencies constrained by leaf chlorophyll observations

Recent studies have shown that estimates of leaf chlorophyll content (Chl), defined as the combined mass of chlorophyll a and chlorophyll b per unit leaf area, can be useful for constraining estimates of canopy light use efficiency (LUE). Canopy LUE describes the amount of carbon assimilated by a vegetative canopy for a given amount of absorbed photosynthetically active radiation (APAR) and is a key parameter for modeling land-surface carbon fluxes. A carbonenabled version of the remote-sensing-based two-source energy balance (TSEB) model simulates coupled canopy transpiration and carbon assimilation using an analytical submodel of canopy resistance constrained by inputs of nominal LUE (βn), which is modulated within the model in response to varying conditions in light, humidity, ambient CO2 concentration, and temperature. Soil moisture constraints on water and carbon exchange are conveyed to the TSEB-LUE indirectly through thermal infrared measurements of landsurface temperature. We investigate the capability of using Chl estimates for capturing seasonal trends in the canopy βn from in situ measurements of Chl acquired in irrigated and rain-fed fields of soybean and maize near Mead, Nebraska. The results show that field-measured Chl is nonlinearly related to βn, with variability primarily related to phenological changes during early growth and senescence. Utilizing seasonally varying βn inputs based on an empirical relationship with in situ measured Chl resulted in improvements in carbon flux estimates from the TSEB model, while adjusting the partitioning of total water loss between plant transpiration and soil evaporation. The observed Chl– βn relationship provides a functional mechanism for integrating remotely sensed Chl into the TSEB model, with the potential for improved mapping of coupled carbon, water, and energy fluxes across vegetated landscapes

Meta-analysis of the detection of plant pigment concentrations using hyperspectral remotely sensed data

Passive optical hyperspectral remote sensing of plant pigments offers potential for understanding plant ecophysiological processes across a range of spatial scales. Following a number of decades of research in this field, this paper undertakes a systematic meta-analysis of 85 articles to determine whether passive optical hyperspectral remote sensing techniques are sufficiently well developed to quantify individual plant pigments, which operational solutions are available for wider plant science and the areas which now require greater focus. The findings indicate that predictive relationships are strong for all pigments at the leaf scale but these decrease and become more variable across pigment types at the canopy and landscape scales. At leaf scale it is clear that specific sets of optimal wavelengths can be recommended for operational methodologies: total chlorophyll and chlorophyll a quantification is based on reflectance in the green (550–560nm) and red edge (680–750nm) regions; chlorophyll b on the red, (630–660nm), red edge (670–710nm) and the near-infrared (800–810nm); carotenoids on the 500–580nm region; and anthocyanins on the green (550–560nm), red edge (700–710nm) and near-infrared (780–790nm). For total chlorophyll the optimal wavelengths are valid across canopy and landscape scales and there is some evidence that the same applies for chlorophyll a

Sequential application of hyperspectral indices for delineation of stripe rust infection and nitrogen deficiency in wheat

© 2015, Springer Science+Business Media New York. Nitrogen (N) fertilization is crucial for the growth and development of wheat crops, and yet increased use of N can also result in increased stripe rust severity. Stripe rust infection and N deficiency both cause changes in foliar physiological activity and reduction in plant pigments that result in chlorosis. Furthermore, stripe rust produce pustules on the leaf surface which similar to chlorotic regions have a yellow color. Quantifying the severity of each factor is critical for adopting appropriate management practices. Eleven widely-used vegetation indices, based on mathematic combinations of narrow-band optical reflectance measurements in the visible/near infrared wavelength range were evaluated for their ability to discriminate and quantify stripe rust severity and N deficiency in a rust-susceptible wheat variety (H45) under varying conditions of nitrogen status. The physiological reflectance index (PhRI) and leaf and canopy chlorophyll index (LCCI) provided the strongest correlation with levels of rust infection and N-deficiency, respectively. When PhRI and LCCI were used in a sequence, both N deficiency and rust infection levels were correctly classified in 82.5 and 55 % of the plots at Zadoks growth stage 47 and 75, respectively. In misclassified plots, an overestimation of N deficiency was accompanied by an underestimation of the rust infection level or vice versa. In 18 % of the plots, there was a tendency to underestimate the severity of stripe rust infection even though the N-deficiency level was correctly predicted. The contrasting responses of the PhRI and LCCI to stripe rust infection and N deficiency, respectively, and the relative insensitivity of these indices to the other parameter makes their use in combination suitable for quantifying levels of stripe rust infection and N deficiency in wheat crops under field conditions

Optical types of inland and coastal waters

Inland and coastal waterbodies are critical components of the global biosphere. Timely monitoring is necessary to enhance our understanding of their functions, the drivers impacting on these functions and to deliver more effective management. The ability to observe waterbodies from space has led to Earth observation (EO) becoming established as an important source of information on water quality and ecosystem condition. However, progress toward a globally valid EO approach is still largely hampered by inconsistences over temporally and spatially variable in-water optical conditions. In this study, a comprehensive dataset from more than 250 aquatic systems, representing a wide range of conditions, was analyzed in order to develop a typology of optical water types (OWTs) for inland and coastal waters. We introduce a novel approach for clustering in situ hyperspectral water reflectance measurements (n = 4045) from multiple sources based on a functional data analysis. The resulting classification algorithm identified 13 spectrally distinct clusters of measurements in inland waters, and a further nine clusters from the marine environment. The distinction and characterization of OWTs was supported by the availability of a wide range of coincident data on biogeochemical and inherent optical properties from inland waters. Phylogenetic trees based on the shapes of cluster means were constructed to identify similarities among the derived clusters with respect to spectral diversity. This typification provides a valuable framework for a globally applicable EO scheme and the design of future EO missions

A Belief System's Organization Based on a Computational Model of the Dynamic Context: First Approximation

In this article we present a model of organization of a belief system based on a set of binary recursive functions that characterize the dynamic context that modifies the beliefs. The initial beliefs are modeled by a set of two-bit words that grow, update, and generate other beliefs as the different experiences of the dynamic context appear. Reason is presented as an emergent effect of the experience on the beliefs. The system presents a layered structure that allows a functional organization of the belief system. Our approach seems suitable to model different ways of thinking and to apply to different realistic scenarios such as ideologies

Роль сугаммадекса при эндоваскулярных вмешательствах на сосудах головного мозга

Highlights. The article discusses the features of general anesthesia in patients with cerebrovascular diseases using the relaxant binding agent sugammadex.Aim. To evaluate the effectiveness of sugammadex in endovascular management of cerebrovascular diseases.Methods. The study included 57 patients who underwent endovascular treatment of cerebrovascular disease under general anesthesia. The experimental group included 29 patients who were injected with sugammadex - a selective relaxant binding agent for reversal of neuromuscular block induced by rocuronium. The comparison group included 28 patients who did not undergo decurarization (n = 13), or it was performed with neostigmine (n = 15). Acceleromyography was used to monitor the state of neuromuscular function.Result. Onset of action and duration of action of rocuronium at a dose of 0.9 mg/kg did not differ between the groups. The neuromuscular recovery time was 2.14 [1.67; 2.59] minutes after administration of sugammadex, compared with spontaneous 35.8 [31.5; 40.4] minutes and neostigmine-induced 22.1 [16.8; 27.3] minutes (p<0.001). No adverse or allergic reactions were noted after administration of the relaxant binding agent.Conclusion. Using a specific antidote sugammadex to eliminate the effect of rocuronium helps to restore neuromuscular function within 2–3 minutes and assess the neurological status of patients immediately after the endovascular treatment of cerebrovascular disease.Основные положения. В статье обсуждаются особенности проведения общей анестезии пациентам с сосудистыми заболеваниями головного мозга с использованием релаксант-связывающего агента сугаммадекса.Цель. Оценка эффективности сугаммадекса при эндоваскулярных вмешательствах на сосудах головного мозга.Материалы и методы. В исследование включены 57 пациентов, которым выполнено рентгенэндоваскулярное вмешательство на сосудах головного мозга в условиях общей анестезии. В исследуемую группу вошли 29 больных, которым вводили сугаммадекс – релаксант-связывающий агент рокурония. Группу сравнения составили 28 пациентов, которым декураризация не выполнена (n = 13) или проведена с помощью неостигмина (n = 15). Для контроля состояния нейромышечной функции использован метод акcелерометрического мониторинга.Результаты. Время начала действия и клиническая продолжительность действия рокурония в дозе 0,9 мг/кг не различались в группах. Время восстановления нейромышечной проводимости после введения сугаммадекса составило 2,14 [1,67; 2,59] мин в сравнении с 35,8 [31,5; 40,4] мин при спонтанном восстановлении и 22,1 [16,8; 27,3] мин при восстановлении, индуцированным неостигмином (p<0,001). Не зафиксировано каких-либо побочных и аллергических реакций после введения релаксант-связывающего агента.Заключение. Использование специфического антидота сугаммадекса для устранения эффекта рокурония позволяет в течение 2–3 мин полностью восстановить нейромышечное проведение и оценить неврологический статус пациентов сразу после окончания эндоваскулярного вмешательства на сосудах головного мозга