Effects of light and soil flooding on the growth and photosynthesis of ramin (Gonystylus bancanus) seedlings in Malaysia

We studied the ecophysiology of ramin (Gonystylus bancanus) seedlings in an experimental set up at the Forest Research Centre in Kuching, Sarawak, Malaysia. Ramin seedlings were grown on flooded and drained peat soil under 100, 76, 46 and 23% sunlight, thus simulating effects of different light conditions (canopy gap size) and drainage that occur in natural ramin populations. Seedling growth was highest in partial sunlight (76%) and reduced with reducing light levels. Aboveground productivity and fine root development were significantly higher in seedlings grown on flooded soil compared with those on drained soil. In contrast, investment in coarse root biomass was significantly higher in seedlings grown on drained soil. It appeared that the aboveground growth benefits in flooded conditions were the result of more advantageous conditions for allocation of carbon to leaves, thus enhancing overall relative growth rates through higher light interception rates despite lower photosynthetic capacity. The results of this experiment suggested that drainage of peat swamp forests would seriously hamper natural regeneration of ramin by limiting the growth of seedlings. It is also suggested that selective logging operations which produce medium-size canopy gaps improve ramin regeneration in hydrologically undisturbed mixed swamp forest

Evaluation of the Storage Conditions and Type of Cork Stopper on the Quality of Bottled White Wines

The effects of different storage conditions, light exposure, temperature and different commercially available cork stoppers on the phenolic, volatile and sensorial profile of Verdejo wines were studied. Two natural corks of different visual quality and a microgranulated cork stopper were investigated over one year at two different storage conditions. One simulating light exposure and temperature in retail outlets and the other simulating optimal cellar conditions (darkness and 12 °C). The wines stored under commercial conditions showed greater losses of total and free SO2 and higher levels of brown-yellowish tones, related to the oxidation of flavan-3-ols. Although these wines underwent a decrease in the total content of stilbenes, a significant increase in trans-piceid was observed. In addition, these wines suffered important changes in their volatile and sensory profile. Volatile compounds with fruity and floral aromas decreased significantly, while volatile compounds related to aged-type characters, as linalool oxides, vitispirane, TDN or furan derivatives increased. Wines stored in darkness at 12 °C underwent minor changes and their sensory profiles were similar to wine before bottling. The high-quality natural corks and microgranulated corks better preserved the quality of the white wines from a sensory point of view. These results showed that temperature and light exposure conditions (diffuse white LEDs and 24 ± 2 °C) in retail outlets considerably decrease the quality of bottled white wines and, consequently, their shelf life, due to the premature development of aged-type charactersThis research was funded by Junta de Comunidades de Castilla-La Mancha (JCCM, Spain), Project SBPLY-17-180501-000445S

Discrete anisotropic radiative transfer (DART 5) for modeling airborne and satellite spectroradiometer and LIDAR acquisitions of natural and urban landscapes

International audienceSatellite and airborne optical sensors are increasingly used by scientists, and policy makers, and managers for studying and managing forests, agriculture crops, and urban areas. Their data acquired with given instrumental specifications (spectral resolution, viewing direction, sensor field-of-view, etc.) and for a specific experimental configuration (surface and atmosphere conditions, sun direction, etc.) are commonly translated into qualitative and quantitative Earth surface parameters. However, atmosphere properties and Earth surface 3D architecture often confound their interpretation. Radiative transfer models capable of simulating the Earth and atmosphere complexity are, therefore, ideal tools for linking remotely sensed data to the surface parameters. Still, many existing models are oversimplifying the Earth-atmosphere system interactions and their parameterization of sensor specifications is often neglected or poorly considered. The Discrete Anisotropic Radiative Transfer (DART) model is one of the most comprehensive physically based 3D models simulating the Earth-atmosphere radiation interaction from visible to thermal infrared wavelengths. It has been developed since 1992. It models optical signals at the entrance of imaging radiometers and laser scanners on board of satellites and airplanes, as well as the 3D radiative budget, of urban and natural landscapes for any experimental configuration and instrumental specification. It is freely distributed for research and teaching activities. This paper presents DART physical bases and its latest functionality for simulating imaging spectroscopy of natural and urban landscapes with atmosphere, including the perspective projection of airborne acquisitions and LIght Detection And Ranging (LIDAR) waveform and photon counting signals

Environmental fog/rain visual display system for aircraft simulators

An environmental fog/rain visual display system for aircraft simulators is described. The electronic elements of the system include a real time digital computer, a caligraphic color display which simulates landing lights of selective intensity, and a color television camera for producing a moving color display of the airport runway as depicted on a model terrain board. The mechanical simulation elements of the system include an environmental chamber which can produce natural fog, nonhomogeneous fog, rain and fog combined, or rain only. A pilot looking through the aircraft wind screen will look through the fog and/or rain generated in the environmental chamber onto a viewing screen with the simulated color image of the airport runway thereon, and observe a very real simulation of actual conditions of a runway as it would appear through actual fog and/or rain

Potential of Lignins as Antioxidant Additive in Active Biodegradable Packaging Materials

Lien vers la version éditeur: http://link.springer.com/article/10.1007/s10924-013-0570-6Due to their polyphenolic structure lignins bear a number of interesting functional properties, such as antioxidant activity. Natural antioxidants are very much looked for in the aim of protection of light or oxygen sensitive goods and are being used in active packaging. Poly(lactide) (PLA)-lignin films were prepared by twin screw extrusion followed by thermo-compression using two different commercial sources of alkali lignins obtained from gramineous plants. A good dispersion of lignin in the matrix was observed. Mechanical properties of the compounded material were merely diminished and oxygen barrier properties slightly enhanced. The chromatographic study of the lignins revealed that the low molecular weight fraction of both lignins increased during the polymer processing. The migration of low molecular weight compounds in an ethanol/water solution simulating fatty foodstuff was performed and the antioxidant activity of the extract was analysed. It was found that the activity increases with increasing severity of the heat treatment because of the generation of free phenolic monomers during processing. These results open an interesting way for application of lignins as an active compound in packaging materials. Lignins do not impair the mechanical and barrier performance of the polymer and the plastics processing even allows for the generation of active substances

Simulating non-axisymmetric flows in disc galaxies

We present a two-step method to simulate and study non-circular motions in strongly barred galaxies. The first step is to constrain the initial parameters using a Bayesian analysis of each galaxy's azimuthally averaged rotation curve, the 3.6 $\rm \mu m$ surface brightness, and the gas surface density. The second step is to generate equilibrium models using the GalactICS code and evolve them via GADGET-2. The bar strengths and mock velocity maps of the resulting snapshots are compared to observations in order to determine the best representation of the galaxy. We test our method on the unbarred galaxy NGC 3621 and the barred galaxies NGC 1300 and NGC 1530. NGC 3621 provides a validation of our method of generating initial conditions. NGC 1530 has an intermediate bar orientation that allows for a comparison to DiskFit. Finally NGC 1300 has a bar oriented parallel to the galaxy's major axis, where other algorithms tend to fail. Our models for NGC 3621 and NGC 1530 are comparable to those obtained using commonly available algorithms. Moreover, we have produced one of the first mass distribution models for NGC 1300.Comment: 19 pages, 15 figures, 5 tables, accepted for publication in A&