Evaluating the use of Beer's law for estimating light interception in canopy architectures with varying heterogeneity and anisotropy

Light interception in plant canopies is most commonly estimated using a simple one-dimensional turbid medium model (i.e., Beer's law). Inherent in this class of models are assumptions that vegetation is uniformly distributed in space (homogeneous) and in many cases that vegetation orientation is uniformly distributed (isotropic). It is known that these assumptions are violated in a wide range of canopies, as real canopies commonly have heterogeneity at multiple scales and almost always have highly anisotropic leaf angle distributions. However, it is not quantitatively known under what conditions these assumptions become problematic given the difficulty of robustly evaluating model results for a range of canopy architectures. In this study, assumptions of vegetation homogeneity and isotropy were evaluated under clear sky conditions for a range of virtually-generated crop canopies with the aid of a detailed three-dimensional, leaf-resolving radiation model. Results showed that Beer's law consistently over predicted light interception for all canopy configurations. For canopies where the plant spacing was comparable to the plant height, Beer's law performed poorly, and over predicted daily intercepted sunlight by up to ∼115%. For vegetation with a highly anisotropic leaf inclination distribution but a relatively isotropic leaf azimuth distribution, the assumption of canopy isotropy (i.e., G = 0.5) resulted in relatively small errors. However, if leaf elevation and azimuth were both highly anisotropic, the assumption of canopy isotropy could introduce significant errors depending on the orientation of the azimuthal anisotropy with respect to the sun's path

Ciência aberta e acesso aberto: Uma abordagem conceitual para ética e qualidade da informação

This review article is a conceptual approach to open science, open access, open data, research ethics, information quality and open research, among other elements closely linked to the open access approach. This article uses as a method the documentary research of the updated literature on the subject and makes a synthetic analysis of each concept. It was found that this paradigm of open science and open access is a current born in the 1990s that relies on technology and the interconnectivity of users to access quality scientific information. The network society is constituted as a social organization in the era of information and communication technologies (ict), where elements such as network connectivity, decentralization, collaboration, access to information, diversity and evolution, which are fundamental characteristics, coexist. The advantages provided by open data and open science are noted: transparency, citizen participation, innovation and creativity, and greater efficiency; without open science and open access implying a waiver of copyright. No less important, the ethics and moral values of our society apply to open access and open science to the extent that researchers maintain scientific integrity, transparency in their results, informed consent and non-manipulation of data. Thus, the binomial ethics and open access are closely linked and both are essential in research work.El presente artículo de revisión es una aproximación conceptual sobre ciencia abierta, acceso abierto, datos abiertos, ética en la investigación, calidad de la información e investigación abierta, entre otros elementos vinculados estrechamente al enfoque del acceso abierto. Este artículo emplea como método la investigación documental de la literatura actualizada sobre la temática y análisis sintético de cada concepto. Se encontró que este paradigma de la ciencia abierta y el acceso abierto es una corriente nacida en los años noventa que se apoya en la tecnología y la interconectividad de los usuarios para acceder a la información científica de calidad. La sociedad red se constituye como una organización social en la era de las tecnologías de la información y las comunicaciones (tic), donde conviven elementos como la conectividad en red, la descentralización, la colaboración, el acceso a la información, la diversidad y la evolución, que son características fundamentales. Se hacen notar las ventajas que proporcionan los datos abiertos y la ciencia abierta: transparencia, participación ciudadana, innovación y creatividad, y mayor eficiencia; sin que la ciencia abierta y el acceso abierto implique una renuncia a los derechos de autor. No menos importante, la ética y los valores morales de nuestra sociedad se aplican al acceso abierto y a la ciencia abierta en la medida en que los investigadores mantienen la integralidad científica, la transparencia en sus resultados, el consentimiento informado y la no manipulación de datos. Así pues, el binomio ética y acceso abierto están estrechamente vinculados y ambos son irrenunciables en la labor investigativa.Este artigo de revisão é uma abordagem conceitual sobre ciência aberta, acesso aberto, dados abertos, ética na pesquisa, qualidade da informação e pesquisa aberta, entre outros elementos intimamente relacionados à abordagem de acesso aberto. O método utilizado neste artigo é a pesquisa documental da literatura atualizada sobre o tema e a análise sintética de cada conceito. Conclui-se que esse paradigma de ciência aberta e acesso aberto é um movimento surgido nos anos noventa que se baseia na tecnologia e na interconectividade dos usuários para acessar informações científicas de qualidade. A sociedade em rede é uma organização social na era da tecnologia da informação e das comunicações (tic), onde convivem elementos como conectividade em rede, descentralização, colaboração, acesso à informação, diversidade e evolução, que são características fundamentais. São destacadas as vantagens proporcionadas pelos dados abertos e pela ciência aberta: transparência, participação cidadã, inovação e criatividade e maior eficiência; sem que a ciência aberta e o acesso aberto impliquem na renúncia aos direitos autorais. Não menos importante, a ética e os valores morais de nossa sociedade se aplicam ao acesso aberto e à ciência aberta na medida em que os pesquisadores mantêm a integridade científica, a transparência em seus resultados, o consentimento informado e a não manipulação de dados. Portanto, a ética e o acesso aberto estão intimamente ligados e ambos são indispensáveis na pesquisa

Sobrecarga y dolor percibido en cuidadoras de ancianos dependientes

Objectives: To evaluate the subjective overload and perceived pain in caregivers of dependent elderly, and to determine if the intensity of perceived pain is associated with the caregiver overload. Material and methods: A transversal study. Variables: age, sex, family relationship, living with the patient, educational level, time as a caregiver, paid work, Caregiver Stress Index (IEC) and pain intensity (VAS).Descriptive and inferential statistical analysis: Student t test, Pearson r and ANOVA, as appropriate. Results: IEC 6.58 ± 1.21, 6.60 ± 1.21 EVA, EVA and IEC correlation r = 0.571, p <0.0001; EVA time as a caregiver and r = 0.340, p <0.026. Conclusions: Carers of dependent elderly have high rates of resistance and pain perception caused by very nature of care required by elderly dependents. Is there a direct relationship between pain intensity and degree of overload of the caregivers.Objetivos: Evaluar la sobrecarga subjetiva y el dolor percibido en cuidadoras de ancianos dependientes y determinar si la intensidad del dolor percibido está asociado a la sobrecarga de la cuidadora. Material y métodos: Estudio observacional, descriptivo transversal. Variables:edad, sexo, parentesco familiar, convivencia con el paciente, nivel educativo, tiempo como cuidador, trabajo remunerado, Índice de Esfuerzo del Cuidador (IEC) e intensidad del dolor (EVA). Análisis estadístico  descriptivo  e inferencial: Test T de Student, r de Pearson y ANOVA, según los casos. Resultados: IEC 6,58 ± 1,21, EVA 6,60 ± 1,21 ; correlación EVA y IEC r= 0,571, p<0,0001; EVA y tiempo como cuidadora r=0,340, p<0,026. Conclusiones: Las cuidadoras de ancianos dependientes presentan elevados índices de sobrecarga y percepción del dolor provocada por propias características de los cuidados que requieren los ancianos dependientes. Existe una relación directa entre la intensidad del dolor y el grado de sobrecarga de las cuidadoras

A [SU(6)]4^4 FLAVOR MODEL WITHOUT MIRROR FERMIONS

We introduce a three family extension of the Pati-Salam model which is anomaly-free and contains in a single irreducible representation the known quarks and leptons without mirror fermions. Assuming that the breaking of the symmetry admits the implementation of the survival hypothesis, we calculate the mass scales using the renormalization group equation. Finally we show that the proton remains perturbatively stable.Comment: Z PHYS. C63, 339 (1994

Abrupt shifts in phenology and vegetation productivity under climate extremes

©2015. American Geophysical Union. All Rights Reserved. Amplification of the hydrologic cycle as a consequence of global warming is predicted to increase climate variability and the frequency and severity of droughts. Recent large-scale drought and flooding over numerous continents provide unique opportunities to understand ecosystem responses to climatic extremes. In this study, we investigated the impacts of the early 21st century extreme hydroclimatic variations in southeastern Australia on phenology and vegetation productivity using Moderate Resolution Imaging Spectroradiometer Enhanced Vegetation Index and Standardized Precipitation-Evapotranspiration Index. Results revealed dramatic impacts of drought and wet extremes on vegetation dynamics, with abrupt between year changes in phenology. Drought resulted in widespread reductions or collapse in the normal patterns of seasonality such that in many cases there was no detectable phenological cycle during drought years. Across the full range of biomes examined, we found semiarid ecosystems to exhibit the largest sensitivity to hydroclimatic variations, exceeding that of arid and humid ecosystems. This result demonstrated the vulnerability of semiarid ecosystems to climatic extremes and potential loss of ecosystem resilience with future mega-drought events. A skewed distribution of hydroclimatic sensitivity with aridity is of global biogeochemical significance because it suggests that current drying trends in semiarid regions will reduce hydroclimatic sensitivity and suppress the large carbon sink that has been reported during recent wet periods (e.g., 2011 La Niña)

5-Dimensional Kaluza-Klein Theory with a Source

A free test particle in 5-dimensional Kaluza-Klein spacetime will show its electricity in the reduced 4-dimensional spacetime when it moves along the fifth dimension. In the light of this observation, we study the coupling of a 5-dimensional dust field with the Kaluza-Klein gravity. It turns out that the dust field can curve the 5-dimensional spacetime in such a way that it provides exactly the source of the electromagnetic field in the 4-dimensional spacetime after the dimensional reduction.Comment: 8 pages, three references adde

A Practical Guide for X-Ray Diffraction Characterization of Ga(Al, In)N Alloys

Ga(In, Al)N alloys are used as an active layer or cladding layer in light emitting diodes and laser diodes. x-ray diffraction is extensively used to evaluate the crystalline quality, the chemical composition and the residual strain in Ga(Al,In)N thin films, which directly determine the emission wavelength and the device performance. Due to the minor mismatch in lattice parameters between Ga(Al, In)N alloy and a GaN virtual substrate, x-ray diffraction comes to a problem to separate the signal from Ga(Al,In)N alloy and GaN. We give a detailed comparison on different diffraction planes. In order to balance the intensity and peak separation between Ga(Al,In)N alloy and GaN, (0004) and (1015) planes make the best choice for symmetric scan and asymmetric scan, respectively.Comment: 9 pages, 5 figure

Routes for the electrochemical degradation of the artificial food azo-colour Ponceau 4R by advanced oxidation processes

The performance of three electrochemical advanced oxidation processes, namely electro-oxidation with electrogenerated H2O2 (EO-H2O2), electro-Fenton (EF) and photoelectro-Fenton (PEF) for the treatment of aqueous solutions of the food azo dye Ponceau 4R in an undivided cell with a BDD anode and an air-diffusion cathode was compared in terms of colour, dye concentration and total organic carbon (TOC) removals. PEF treatments in ultrapure water with Na2SO4 were performed to assess the effect of current density, as well as supporting electrolyte and dye concentrations. At 100 mA cm-2, solutions of 130 mL of 254 mg L-1 of the dye in 0.05 M Na2SO4 became colourless and totally mineralized after 50 and 240 min, respectively, which can be explained by the synergistic action of BDD(¿OH) at the anode surface and homogeneous ¿OH formed in the bulk from Fenton's reaction promoted in the presence of Fe2+ catalyst. Furthermore, UVA photons induced the continuous Fe2+ regeneration and photolytic decomposition of refractory intermediate complexes. In that aqueous matrix, the cleavage of the dye molecules proceeded through several reaction routes to yield N-containing and non-N-containing derivatives with one or two aromatic rings, short-chain aliphatic carboxylic acids and inorganic ions. Oxalic and oxamic acids and sulfate ions were accumulated at different rates in EO-H2O2, EF and PEF. The three methods allowed the progressive decontamination of Ponceau 4R solutions in a real water matrix even without the addition of electrolyte, although complete TOC abatement after 360 min at 33.3 mA cm-2 was only ensured by the iron-catalyzed PEF process