Effects of different light levels on the initial growth and photosynthesis of Croton urucurana Baill. in southeastern Brazil

Four levels of shading (full sunlight (0%), 30, 50, 70% of solar radiation interception on growth, chlorophyll concentration and photosynthetic rate were studied in Croton urucurana Baill., a pioneer plant species. This species seedlings are of potential interest for reforestation projects and recovery of degraded areas. The seedlings were grown in pots containing soil and sand (2:1) and later transferred to plastic bags of 3 dm³ and submitted to different levels of shading (30, 50, 70%) of solar radiation and full sunlight, as control. The experimental design was completely randomized with five replicates and each experimental unit was composed of five plants. The results suggest that plants submitted to 70% shading showed higher dry weight accumulation in leaf and root, and higher plant height and leaf area. However, the seedlings root system showed higher dry biomass under full sunlight. It was observed a tendency to increase chlorophyll concentration and to decrease photosynthetic rate with the increase of the shading level.

Effect of light intensity and growth substratum on plant development and production of secondary metabolites in Cordia curassavica (Jacq.) Roem. & Schult

Cordia curassavica (Jacq.) Roem. & Schult. (Boraginaceae), also referred to as Cordia verbenacea DC, has been traditionally used for medicinal purposes. This study was driven to verify the behavior of the species in similar conditions to its natural environment, such as high light intensity and sandbank soil, and in conditions of low light intensity and fertilized substratum (dystroferric red nitosoil plus earthworm humus). The growth of the plant, the income of leaf crude extracts and, in the alcoholic extract, the number of substances found in thin layer cromatography and the toxicity of the substratum was observed. The results indicated that the growth of the root biomass, stem and leaves in discharge or lower light intensity was similar, but smaller in sandbank soil than in fertilized soil. The relative income of extracts in ether of petroleum and alcohol was larger in high light intensity and fertilized substratum. The light intensity and the substratum type didn't affect the number of substances detected in the alcoholic extract or the toxicity of this extract. Stains corresponding to the rosmarinic acid were only evidenced in some samples of the alcoholic extract, not allowing the verification of the effect of the treatments about its production.

Upconverting Phosphor Technology: Exceptional Photoluminescent Properties Light Up Homogeneous Bioanalytical Assays

The aim of the present study was to demonstrate the wide applicability of the novel photoluminescent labels called upconverting phosphors (UCPs) in proximity-based bioanalytical assays. The exceptional features of the lanthanide-doped inorganic UCP compounds stem from their capability for photon upconversion resulting in anti-Stokes photoluminescence at visible wavelengths under near-infrared (NIR) excitation. Major limitations related to conventional photoluminescent labels are avoided, rendering the UCPs a competitive next-generation label technology. First, the background luminescence is minimized due to total elimination of autofluorescence. Consequently, improvements in detectability are expected. Second, at the long wavelengths (>600 nm) used for exciting and detecting the UCPs, the transmittance of sample matrixes is significantly greater in comparison with shorter wavelengths. Colored samples are no longer an obstacle to the luminescence measurement, and more flexibility is allowed even in homogeneous assay concepts, where the sample matrix remains present during the entire analysis procedure, including label detection. To transform a UCP particle into a biocompatible label suitable for bioanalytical assays, it must be colloidal in an aqueous environment and covered with biomolecules capable of recognizing the analyte molecule. At the beginning of this study, only UCP bulk material was available, and it was necessary to process the material to submicrometer-sized particles prior to use. Later, the ground UCPs, with irregular shape, wide size-distribution and heterogeneous luminescence properties, were substituted by a smaller-sized spherical UCP material. The surface functionalization of the UCPs was realized by producing a thin hydrophilic coating. Polymer adsorption on the UCP surface is a simple way to introduce functional groups for bioconjugation purposes, but possible stability issues encouraged us to optimize an optional silica-encapsulation method which produces a coating that is not detached in storage or assay conditions. An extremely thin monolayer around the UCPs was pursued due to their intended use as short-distance energy donors, and much attention was paid to controlling the thickness of the coating. The performance of the UCP technology was evaluated in three different homogeneous resonance energy transfer-based bioanalytical assays: a competitive ligand binding assay, a hybridization assay for nucleic acid detection and an enzyme activity assay. To complete the list, a competitive immunoassay has been published previously. Our systematic investigation showed that a nonradiative energy transfer mechanism is indeed involved, when a UCP and an acceptor fluorophore are brought into close proximity in aqueous suspension. This process is the basis for the above-mentioned homogeneous assays, in which the distance between the fluorescent species depends on a specific biomolecular binding event. According to the studies, the submicrometer-sized UCP labels allow versatile proximity-based bioanalysis with low detection limits (a low-nanomolar concentration for biotin, 0.01 U for benzonase enzyme, 0.35 nM for target DNA sequence).

Initial growth of Bauhinia variegata trees under different colored shade nets and light conditions

Bauhinia variegata and B. variegata var. candida, commonly known as orchid trees, are small sized trees widely used for urban forestry and landscaping. Adult plants grow under full sun; in Brazil, however, seedlings are generally cultivated in commercial nurseries under natural half-shading. The objective of this study was to evaluate the influence of different colored shade nets and light conditions on the initial growth of B. variegata and B. variegata var. candida. The influence of six light conditions (red net with 50% shading; blue net with 50% shading; black net with 70% shading; black net with 50% shading; black net with 30% shading; and full sun) on the initial growth of B. variegata and B. variegata var. candida were evaluated along 160 days, and growth relationships were calculated. Seedlings showed more efficiency on the use of photoassimilated compounds when grown under full sun. Such condition is the most appropriate for seedling production of B. variegata and B. variegata var. candida, contradicting what has been performed in practice.

Information exchange and disruption risk in multimodal maritime supply chains

Supply chains are becoming increasingly dependent on information ex-change in today’s world, and any disruption can cause severe repercus-sions to the flow of materials in the chain. The speed, accuracy and amount of information are key factors. The aim in this thesis is to address a gap in the research by focusing on information exchange and the risks related to it in a multimodal wood supply chain operating between the Baltic States and Finland. The study involved interviewing people engaged in logistics management in the supply chain in question. The main risk the interviewees identified arose from the sea logistics system, which held a lot of different kinds of information. The threat of breakdown in the Internet connection was also found to hinder the operations significantly. A vulnerability analysis was carried out in order to identify the main actors and channels of infor-mation flow in the supply chain. The analysis revealed that the most important and therefore most vulnerable information-exchange channels were those linking the terminal superintendent, the operative managers and the mill managers. The study gives a holistic picture of the investigated supply chain. Information-exchange-related risks varied greatly. One of the most frequently mentioned was the risk of information inaccuracy, which was usually due to the fact that those in charge of the various functions did not fully understand the consequences for the entire chain.

Light emitting diode (LED) use in artificial lighting for broiler chicken production

Light emitting diode (LED) has been used in commercial poultry industry by presenting superior energy savings and providing feasibility on production process. The objective of this research was to evaluate performance and carcass yield of broiler chickens exposed to different LED colors compared with fluorescent lamps. For that, two experiments (E1 and E2) were performed and 2,646 Cobb® chickens were used. In experiment E1, male birds were exposed to 20 lux artificial lighting with red, yellow, blue, and white LED bulbs; and fluorescent bulb. In experiment E2, male and female birds were exposed to 15 lux artificial lighting with red and blue LED bulbs; and fluorescent bulb. Cumulative weight gain (kg), feed intake (kg), feed conversion, hot carcass weight (kg), carcass yield (%), and breast and thigh + drumstick yield (%) were used as response variables. Results showed no difference (p > 0.05) among treatments for performance, carcass yield, and cut yield in experiment E1. In experiment E2 there was only difference between genders (p < 0.05) and males showed higher total weight gain, feed intake, hot carcass weight and thigh + drumstick yield. Different LED color use had same effect as fluorescent lights on broiler performance and carcass yield.

Impact of different light sources on broiler rearing environment

Broiler production is highly dependent on the use of artificial light. The light source may affect the effectiveness of housing conditions due to increasing ambient temperature and concentration of noxious gases. This research aimed to evaluate the effects of different bulb types on the thermal, aerial, and acoustic environment of broiler aviaries. The experiment was carried out at a commercial broiler farm in Dourados, Mato Grosso do Sul State, Brazil. Three aviaries were used, and two flocks of male broilers from Cobb® genetic strain were reared from the first day to slaughter. Each aviary was equipped with a different light source, comprising the adopted treatments (A1 - incandescent light bulb, control; A2 - sodium vapor light bulb; A3 - fluorescent light bulb). The aviaries were divided into nine quadrants, and the environmental data (ambient dry bulb temperature and relative humidity), litter surface temperature, CO2 and NH3 concentrations, and bird sound pressure behavior were recorded in each quadrant. The aviary with incandescent light presented higher air and litter temperatures, and concentration of gases than the other tested alternatives. It also presented higher level of sound pressure in the second week of the growing period; however, from this period up to slaughter, there was no effect of the light source on the results of broiler sound pressure level.

Effects of light intensity modification by reflective aluminized screenhouse on sweet pepper growth and yield

Sweet pepper is one of the ten most consumed vegetables in world. Although it develops better under protected environment, the cultivation in tropical countries is practiced in open field due greenhouse structure higher costs. Unfortunately, such practice has compromised the crop to reach either best yield or fruit quality. Since production and cost are the most important criteria for agricultural production, we aimed to evaluate reflective aluminized polypropylene shading net influence on sweet pepper (Capsicum annuum L.) growth and production as intermediary alternative for low/middle income producers from Brazilian tropical regions. Sweet pepper Magali R hybrid was cultivated in two environments: FC - field conditions (control) and RS - reflective shading net with 40% shading rate. RS caused reductions in incident solar radiation (SR) and photosynthetically active radiation (PAR) on the amount of 46.3% and 48.3%, respectively. There were no significant changes in temperature and relative humidity recorded for the two environments. In addition, RS allowed best use efficiency of photosynthetically active radiation since it promoted higher values of plant height, leaf number and area index than those reached on FC on the amount of 29%, 22% and 80 %, respectively. Similarly, plants grown under RS showed higher yield and marketable fruits and promoted less loses by sunscald.

Greenhouse gas emissions from peat and biomass-derived fuels, electricity and heat — Estimation of various production chains by using LCA methodology

More discussion is required on how and which types of biomass should be used to achieve a significant reduction in the carbon load released into the atmosphere in the short term. The energy sector is one of the largest greenhouse gas (GHG) emitters and thus its role in climate change mitigation is important. Replacing fossil fuels with biomass has been a simple way to reduce carbon emissions because the carbon bonded to biomass is considered as carbon neutral. With this in mind, this thesis has the following objectives: (1) to study the significance of the different GHG emission sources related to energy production from peat and biomass, (2) to explore opportunities to develop more climate friendly biomass energy options and (3) to discuss the importance of biogenic emissions of biomass systems. The discussion on biogenic carbon and other GHG emissions comprises four case studies of which two consider peat utilization, one forest biomass and one cultivated biomasses. Various different biomass types (peat, pine logs and forest residues, palm oil, rapeseed oil and jatropha oil) are used as examples to demonstrate the importance of biogenic carbon to life cycle GHG emissions. The biogenic carbon emissions of biomass are defined as the difference in the carbon stock between the utilization and the non-utilization scenarios of biomass. Forestry-drained peatlands were studied by using the high emission values of the peatland types in question to discuss the emission reduction potential of the peatlands. The results are presented in terms of global warming potential (GWP) values. Based on the results, the climate impact of the peat production can be reduced by selecting high-emission-level peatlands for peat production. The comparison of the two different types of forest biomass in integrated ethanol production in pulp mill shows that the type of forest biomass impacts the biogenic carbon emissions of biofuel production. The assessment of cultivated biomasses demonstrates that several selections made in the production chain significantly affect the GHG emissions of biofuels. The emissions caused by biofuel can exceed the emissions from fossil-based fuels in the short term if biomass is in part consumed in the process itself and does not end up in the final product. Including biogenic carbon and other land use carbon emissions into the carbon footprint calculations of biofuel reveals the importance of the time frame and of the efficiency of biomass carbon content utilization. As regards the climate impact of biomass energy use, the net impact on carbon stocks (in organic matter of soils and biomass), compared to the impact of the replaced energy source, is the key issue. Promoting renewable biomass regardless of biogenic GHG emissions can increase GHG emissions in the short term and also possibly in the long term.

Ocorrência de plantas aquáticas nos reservatórios da Light-RJ

O objetivo do presente trabalho foi caracterizar as comunidades infestantes de plantas aquáticas presentes nos reservatórios da Light-Sistema de Eletricidade S.A., localizada no município de Piraí-RJ. Os levantamentos foram realizados no período de julho a setembro de 1998. Os reservatórios analisados foram: Vigário, Pereira Passos e Lajes, sendo as quantidades de pontos amostrados de 19, 9 e 15, respectivamente. Em cada ponto amostrado fez-se a marcação das coordenadas geográficas e avaliou-se a porcentagem de ocupação do corpo d'água pelas espécies de plantas aquáticas presentes. Depois da identificação das plantas, pôde-se verificar quais eram as espécies mais freqüentes e a sua distribuição dentro do sistema de geração de energia. As espécies encontradas nos reservatórios foram: Brachiaria arrecta (Hack.) Stent.; Egeria densa Planch.; Eichhornia azurea (Sw.) Kunth.; Eichhornia crassipes (Mart.) Solms.; Hymenachne amplexicaulis (Rudge) Nees.; Panicum rivulare Trin.; Pistia stratiotis L.; Polygonum spp.; Sagitaria montevidensis Cham. & Schlecht; Salvinia auriculata (Micheli) Adans; e Thypha dominguensis L.

Perspectives for using light quality knowledge as an advanced ecophysiological weed management tool

The current knowledge of light quality effects on plant morphogenesis and development represents a new era of understanding on how plant communities perceive and adjust to available resources. The most important consequences of light quality cues, often mediated by decreasing in red far-red ratios with respect to the spectral composition of incident sunlight radiation, affecting weed-crop interaction are the increased plant height and shoot to root ratio in anticipation of competition by light quantity, water or nutrients. Although the concepts related to light quality have been extensively studied and several basic process of this phenomenon are well known, little applications of photomorphogenic signaling currently are related to agricultural problems or weed management. The objectives of this review are to describe how light quality change can be a triggering factor of interspecific interference responses, to analyze how this phenomenon can be used to predict weed interference, to reevaluate the critical periods of interference concept, and to discuss its potential contribution towards developing more weed competitive crop varieties. Knowledge on light quality responses involved in plant sensing of interspecific competition could be used to identify red/far-red threshold values, indicating when weed control should be started. Light quality alterations by weeds can affect grain crop development mainly in high yielding fields. Unlike the traditional concept or the critical period of competition, light quality mediated interference implies that the critical period for weed control could start before the effects of direct resource (water, nutrients and available light) limitation actually occur. The variability in light quality responses among crop genotypes and the identification of mutants insensitive to light quality effects indicate that this characteristic can be selected or modified to develop cultivars with enhanced interspecific interference ability. Knowledge on light quality-elicited responses represents a new possibility to understand the underlying biology of interspecific interference, and could be used in the development of new weed management technologies.

Modeling light interception and distribution in mixed canopy of common cocklebur (Xanthium stramarium) in competition with corn

The aim of this study was to model light interception and distribution in the mixed canopy of Common cocklebur (Xanthium stramarium) with corn. An experiment was conducted in factorial arrangement on the basis of randomized complete blocks design with three replications in Gonabad in 2006-2007 and 2007-2008 seasons. The factors used in this experiment include corn density of 7.5, 8.5 and 9.5 plants per meter of row and density of Common cocklebur of zero, 2, 4, 6 and 8 plants per meter of row. INTERCOM model was used through replacing parabolic function with triangular function of leaf area density. Vertical distribution of the species' leaf area showed that corn has concentrated the most leaf area in layer of 80 to 100 cm while Common cocklebur has concentrated in 35-50 cm of canopy height. Model sensitivity analysis showed that leaf area index, species' height, height where maximum leaf area is seen (hm), and extinction coefficient have influence on light interception rate of any species. In both species, the distribution density of leaf area at the canopy length fit a triangular function, and the height in which maximum leaf area was observed was changed by change in density. There was a correlation between percentage of the radiation absorbed by the weed and percentage of corn seed yield loss (r² = 0.89). Ideal type of corn was determined until the stage of tasseling in competition with weed. This determination indicates that the corn needs more height and leaf area, as well as less extinction coefficient to successfully fight against the weed.