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Varying Environmental Conditions (varying + environmental_condition)
Selected Abstracts133 Studies on the Life History of the Portuguese Red Alga Porphyra Dioica (Brodie and Irvine) Under Varying Environmental ConditionsJOURNAL OF PHYCOLOGY, Issue 2003R. Pereira The life history of Porphyra dioica collected in Porto, Portugal, was investigated under laboratory conditions. This is one of the most common Porphyra species on the North Coast of Portugal and can be found throughout the year. Field studies showed higher percentage cover, from 23 to 66%, during February through May. Varying temperature, light intensities and photoperiods were tested. The zygotospores germinated faster at 15°C, and at 25 ,mol m,2·s,1. Growth rate of the conchocelis was affected by temperature rather than by photoperiod. In the three photoperiods tested, growth rate was always higher at 15°C, under 25 to 75 ,mol m,2·s,1, although not significantly different from that at 20° C. Difference between these two temperatures and 5 and 10°C was significant. Conchosporangia formation was higher in 15°C and at short-day, 8:16, Light:Dark and 25 to 75 ,mol m,2·s,1 and was almost non-existent in free floating conditions. Optimal conditions for conchosporangia maturation, 15° C, 8:16, Light:Dark and 5 to 25 ,mol m,2·s,1 also promoted spore release after 18 weeks. Aeration appeared to be crucial for normal blade development. No archeospores were observed. The first findings of the optimal conditions for growth of the gametophyte stage will also be discussed. [source] Efficiency of permeable pavement systems for the removal of urban runoff pollutants under varying environmental conditionsENVIRONMENTAL PROGRESS & SUSTAINABLE ENERGY, Issue 3 2010Kiran Tota-Maharaj Abstract Urban surface water runoff typically contains a high but variable number of pathogens, nutrients, and sediments that require removal before reuse. Permeable pavements can improve the water quality through interception, filtration, sedimentation, nutrient transformation, and microbial removal. There is currently insufficient scientific information available on the treatment efficiencies of permeable pavements combined with earth energy systems with regards to the removal of storm water pollutants such as nutrients, sediments, and microbial pollutants. This study evaluates the efficiency of 12 tanked combined systems during a medium-term study. The research assessed weekly the removal of the microbial indicators total coliforms, Escherichia coli, and fecal Streptococci, as well as the key nutrients ammonia-nitrogen, nitrate-nitrogen, and ortho-phosphate-phosphorus, and physical variables such as suspended solids and turbidity. Total coliforms, E. coli, and fecal Streptococci were removed by 98,99%. The ammonia-nitrogen and ortho-phosphate-phosphorus removal efficiencies were 84.6% and 77.5%, respectively. An analysis of variance indicated that the presence or absence of a geotextile did result in a very highly statistically significant difference (P < 0.001) with respect to the removal of both ammonia-nitrogen and ortho-phosphate-phosphorus. Suspended solids, turbidity, and biochemical oxygen demand were reduced by 91%, 82%, and 88%, respectively. These results indicate the potential of the proposed novel system in urban runoff pollutant removal and subsequent reuse of the treated water. © 2010 American Institute of Chemical Engineers Environ Prog, 2010 [source] Performance of laser and radar ranging devices in adverse environmental conditionsJOURNAL OF FIELD ROBOTICS (FORMERLY JOURNAL OF ROBOTIC SYSTEMS), Issue 9 2009Julian Ryde A comparative evaluation of millimeter-wave radar and two-dimensional scanning lasers in dust and rain conditions for sensor applications in field robotics is presented. A robust and reliable method for measuring the level of suspended dust (or other obscurant media) by determining the transmission coefficient is developed and used for quantitative assessment of sensor performance. The criteria of target acquisition reliability, precision, and accuracy under varying environmental conditions are assessed via sensor operation in a controlled environment. This environment generated dust and rain of varying densities. Sensor performance is also assessed for the potential effect on digital terrain mapping and haul truck localization due to sensor-specific behaviors in these conditions (e.g., false targets, increased noise). Trials on a research electric face shovel are conducted to test observed behaviors. It is concluded that laser scanners are suitable for environments with transmissions exceeding 92%,93%/m for targets closer than 25 m. The radar remained relatively unaffected by the generated conditions of rain (50,70 mm/h) and dust (10-m visibility); however, its accuracy (0.1 m with a corner reflector and 0.3 m on a haul truck), free-space clutter, and scan rate were insufficient for locating unmodified haul trucks for this application. © 2009 Wiley Periodicals, Inc. [source] Antibody response of two populations of common carp, Cyprinus carpio L., exposed to koi herpesvirusJOURNAL OF FISH DISEASES, Issue 4 2009S St-Hilaire Abstract Common carp, Cyprinus carpio L., exposed to koi herpesvirus (KHV) may become persistently infected and populations containing such virus-infected individuals may transmit the virus to other fish when co-habited. Detection of virus-infected fish in a population is thus critical to surveillance and control programmes for KHV. A study was therefore designed to detect anti-KHV serum antibodies, with an enzyme-linked immunosorbent assay, in common carp following experimental exposures to KHV under varying environmental conditions. The study determined that a proportion of fish within a population experimentally exposed to KHV (at least 10,25%) develop high antibody titres (1/1600 or greater) to the virus, and this immunological response was detectable for several months (observed at the termination of the experiments at 65, 46 and 27 weeks post-exposure). Furthermore, this response was detected in one population of fish that did not succumb to a high level of mortality when maintained at water temperatures that were non-permissive for KHV. Elevating the water temperatures to permissive conditions for KHV resulted in recurrence of disease despite the presence of anti-virus antibodies, suggesting that serum antibodies alone are not protective under the conditions of our trials. [source] Variation in virus populations and growth characteristics of two sugarcane cultivars naturally infected by Sugarcane yellow leaf virus in different geographical locationsPLANT PATHOLOGY, Issue 5 2007Y. Abu Ahmad Two sugarcane cultivars (R570 and SP71-6163) naturally infected by Sugarcane yellow leaf virus (SCYLV) were each imported from several geographical locations into a sugarcane yellow leaf-free environment (Montpellier, France). Plants were grown as plant cane for 5,6 months and the experiment was repeated for three consecutive years (2003,2005) in a greenhouse. Several sugarcane-growth and disease characteristics were monitored to identify variation in pathogenicity of SCYLV. Depending on their geographical origin, sugarcane cvs R570 and SP71-6163 were infected by SCYLV genotypes BRA-PER or REU, or a mixture of the two. Severity of symptoms did not vary between plants of cv. R570, but variation in disease severity between plants of cv. SP71-6163 from different geographical locations suggested the occurrence of pathogenic variants of SCYLV. For each sugarcane cultivar, differences in stalk length, number of stalk internodes, virus titre in the top visible dewlap leaf, and percentage of infection of leaf and stalk phloem vessels were also found between plants from different geographical origins. However, these differences were not always reproducible from one year to another, suggesting occurrence of different plant responses to SCYLV isolates under varying environmental conditions. [source] A reporter system for the individual detection of hydrogen peroxide and singlet oxygen: its use for the assay of reactive oxygen species produced in vivoTHE PLANT JOURNAL, Issue 3 2007Ning Shao Summary A reporter system for the assay of reactive oxygen species (ROS) was developed in Chlamydomonas reinhardtii, a plant model organism well suited for the application of inhibitors and generators of various types of ROS. This system employs various HSP70A promoter segments fused to a Renilla reniformis luciferase gene as a reporter. Transformants with the complete HSP70A promoter were inducible by both hydrogen peroxide and singlet oxygen. Constructs that lacked upstream heat-shock elements (HSEs) were inducible by hydrogen peroxide, indicating that this induction does not require such HSEs. Rather, downstream elements located between positions ,81 to ,149 with respect to the translation start site appear to be involved. In contrast, upstream sequences are essential for the response to singlet oxygen. Thus, activation by singlet oxygen appears to require promoter elements that are different from those used by hydrogen peroxide. ROS generated endogenously by treatment of the alga with metronidazole, protoporphyrin IX, dinoterb or high light intensities were detected by this reporter system, and distinguished as production of hydrogen peroxide (metronidazole) and singlet oxygen (protoporphyrin IX, dinoterb, high light). This system thus makes it possible to test whether, under varying environmental conditions including the application of abiotic stress, hydrogen peroxide or singlet oxygen or both are produced. [source] | |||||||||||||