4,273 research outputs found

    Arthropods Associated With Purple Loosestrife in Illinois Wetlands

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    We estimated and described the arthropod fauna on purple loosestrife (Lythrum salicaria) plants in northeastern Illinois wetlands. A total of 1063 individual arthropods were collected—930 insects and 133 arachnids. The av- erage number of arthropods ranged from 19.00 to 86.75 individuals per loos- estrife plants of a single root crown. We collected individuals from twenty-five families representing 8 orders of insects. Miridae, Anthocoridae, Lygaeidae, Cicadellidae, and Aphididae were each represented by at least 50 individuals. Three orders and ten families were found that had not been previously reported as occurring on purple loosestrife, but many of these taxa were represented by only a few individuals

    Screening by coral green fluorescent protein (GFP)-like chromoproteins supports a role in photoprotection of zooxanthellae

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    Green fluorescent protein (GFP)-like pigments are responsible for the vivid colouration of many reef-building corals and have been proposed to act as photoprotectants. Their role remains controversial because the functional mechanism has not been elucidated. We provide direct evidence to support a photoprotective role of the non-fluorescent chromoproteins (CPs) that form a biochemically and photophysically distinct group of GFP-like proteins. Based on observations of Acropora nobilis from the Great Barrier Reef, we explored the photoprotective role of CPs by analysing five coral species under controlled conditions. In vitro and in hospite analyses of chlorophyll excitation demonstrate that screening by CPs leads to a reduction in chlorophyll excitation corresponding to the spectral properties of the specific CPs present in the coral tissues. Between 562 and 586 nm, the CPs maximal absorption range, there was an up to 50 % reduction of chlorophyll excitation. The screening was consistent for established and regenerating tissue and amongst symbiont clades A, C and D. Moreover, among two differently pigmented morphs of Acropora valida grown under identical light conditions and hosting subclade type C3 symbionts, high CP expression correlated with reduced photodamage under acute light stress

    The Distribution and Prevalence of the Alfalfa Blotch Leafminer (Diptera: Agromyzidae) in Illinois

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    Surveys were made in 2001 and 2002 to determine the distribution and prevalence of the alfalfa blotch leafminer, Agromyza frontella (Diptera: Agromyzidae), and its primary parasitoids, Dacnusa dryas and Chrysocharis liriomyzae (Hymenoptera: Braconidae and Eulophidae, respectively), in Illinois. We collected 239 samples from alfalfa fields in the alfalfa-producing regions of Illinois. Samples from each site consisted of 20 cut stems and 10 sets of 10 sweeps in 2001, and 40 stems and 10 sets of 20 sweeps in 2002. Each trifoliate was examined for mining and pinholing injury, and the number of adult A. frontella, D. dryas, and C. liriomyzae per 10 sweeps was calculated for each site. We found that 16.3% of the sites were infested with A. frontella, and all infested fields were north of 39.95 N latitude. Although up to 95% of stems were injured at some sites, mean injury per stem never exceeded 12% of trifoliates. Maximum adult abundance was 8.1 adults per 10 sweeps. We did not detect D. dryas or C. liriomyzae in any of the sweep samples. Because of consistently low populations and the relatively slow rate of A. frontella’s spread in Illinois, we conclude that A. frontella is not a serious threat to alfalfa production in this state at this time

    Fluorescent protein-mediated colour polymorphism in reef corals: multicopy genes extend the adaptation/acclimatization potential to variable light environments

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    The genomic framework that enables corals to adjust to unfavourable conditions is crucial for coral reef survival in a rapidly changing climate. We have explored the striking intraspecific variability in the expression of coral pigments from the green fluorescent protein (GFP) family to elucidate the genomic basis for the plasticity of stress responses among reef corals. We show that multicopy genes can greatly increase the dynamic range over which corals can modulate transcript levels in response to the light environment. Using the red fluorescent protein amilFP597 in the coral Acropora millepora as a model, we demonstrate that its expression increases with light intensity, but both the minimal and maximal gene transcript levels vary markedly among colour morphs. The pigment concentration in the tissue of different morphs is strongly correlated with the number of gene copies with a particular promoter type. These findings indicate that colour polymorphism in reef corals can be caused by the environmentally regulated expression of multicopy genes. High-level expression of amilFP597 is correlated with reduced photodamage of zooxanthellae under acute light stress, supporting a photoprotective function of this pigment. The cluster of light-regulated pigment genes can enable corals to invest either in expensive high-level pigmentation, offering benefits under light stress, or to rely on low tissue pigment concentrations and use the conserved resources for other purposes, which is preferable in less light-exposed environments. The genomic framework described here allows corals to pursue different strategies to succeed in habitats with highly variable light stress levels. In summary, our results suggest that the intraspecific plasticity of reef corals’ stress responses is larger than previously thought

    A possible solution of the grain boundary problem for applications of high-Tc superconductors

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    It is shown that the critical current density of high-Tc wires can be greatly enhanced by using a threefold approach, which consists of grain alignment, doping, and optimization of the grain architecture. According to model calculations, current densities of 4x10^6 A/cm2 can be achieved for an average grain alignment of 10 degree at 77K. Based on this approach, a road to competitive high-Tc cables is proposed.Comment: 3 pages, 5 figure

    Arthropods Associated With Purple Loosestrife in Illinois Wetlands

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    We estimated and described the arthropod fauna on purple loosestrife (Lythrum salicaria) plants in northeastern Illinois wetlands. A total of 1063 individual arthropods were collected—930 insects and 133 arachnids. The av- erage number of arthropods ranged from 19.00 to 86.75 individuals per loos- estrife plants of a single root crown. We collected individuals from twenty-five families representing 8 orders of insects. Miridae, Anthocoridae, Lygaeidae, Cicadellidae, and Aphididae were each represented by at least 50 individuals. Three orders and ten families were found that had not been previously reported as occurring on purple loosestrife, but many of these taxa were represented by only a few individuals

    Symbiodinium thermophilum sp. nov., a thermotolerant symbiotic alga prevalent in corals of the world's hottest sea, the Persian/Arabian Gulf

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    Coral reefs are in rapid decline on a global scale due to human activities and a changing climate. Shallow water reefs depend on the obligatory symbiosis between the habitat forming coral host and its algal symbiont from the genus Symbiodinium (zooxanthellae). This association is highly sensitive to thermal perturbations and temperatures as little as 1°C above the average summer maxima can cause the breakdown of this symbiosis, termed coral bleaching. Predicting the capacity of corals to survive the expected increase in seawater temperatures depends strongly on our understanding of the thermal tolerance of the symbiotic algae. Here we use molecular phylogenetic analysis of four genetic markers to describe Symbiodinium thermophilum, sp. nov. from the Persian/Arabian Gulf, a thermally tolerant coral symbiont. Phylogenetic inference using the non-coding region of the chloroplast psbA gene resolves S. thermophilum as a monophyletic lineage with large genetic distances from any other ITS2 C3 type found outside the Gulf. Through the characterisation of Symbiodinium associations of 6 species (5 genera) of Gulf corals, we demonstrate that S. thermophilum is the prevalent symbiont all year round in the world's hottest sea, the southern Persian/Arabian Gulf

    The Distribution and Prevalence of the Alfalfa Blotch Leafminer (Diptera: Agromyzidae) in Illinois

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    Surveys were made in 2001 and 2002 to determine the distribution and prevalence of the alfalfa blotch leafminer, Agromyza frontella (Diptera: Agromyzidae), and its primary parasitoids, Dacnusa dryas and Chrysocharis liriomyzae (Hymenoptera: Braconidae and Eulophidae, respectively), in Illinois. We collected 239 samples from alfalfa fields in the alfalfa-producing regions of Illinois. Samples from each site consisted of 20 cut stems and 10 sets of 10 sweeps in 2001, and 40 stems and 10 sets of 20 sweeps in 2002. Each trifoliate was examined for mining and pinholing injury, and the number of adult A. frontella, D. dryas, and C. liriomyzae per 10 sweeps was calculated for each site. We found that 16.3% of the sites were infested with A. frontella, and all infested fields were north of 39.95 N latitude. Although up to 95% of stems were injured at some sites, mean injury per stem never exceeded 12% of trifoliates. Maximum adult abundance was 8.1 adults per 10 sweeps. We did not detect D. dryas or C. liriomyzae in any of the sweep samples. Because of consistently low populations and the relatively slow rate of A. frontella’s spread in Illinois, we conclude that A. frontella is not a serious threat to alfalfa production in this state at this time

    A configuration system for the ATLAS trigger

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    The ATLAS detector at CERN's Large Hadron Collider will be exposed to proton-proton collisions from beams crossing at 40 MHz that have to be reduced to the few 100 Hz allowed by the storage systems. A three-level trigger system has been designed to achieve this goal. We describe the configuration system under construction for the ATLAS trigger chain. It provides the trigger system with all the parameters required for decision taking and to record its history. The same system configures the event reconstruction, Monte Carlo simulation and data analysis, and provides tools for accessing and manipulating the configuration data in all contexts.Comment: 4 pages, 2 figures, contribution to the Conference on Computing in High Energy and Nuclear Physics (CHEP06), 13.-17. Feb 2006, Mumbai, Indi

    Water column productivity and temperature predict coral reef regeneration across the Indo-Pacific

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    Predicted increases in seawater temperatures accelerate coral reef decline due to mortality by heat-driven coral bleaching. Alteration of the natural nutrient environment of reef corals reduces tolerance of corals to heat and light stress and thus will exacerbate impacts of global warming on reefs. Still, many reefs demonstrate remarkable regeneration from past stress events. This paper investigates the effects of sea surface temperature (SST) and water column productivity on recovery of coral reefs. In 71 Indo-Pacific sites, coral cover changes over the past 1-3 decades correlated negative-exponentially with mean SST, chlorophyll a, and SST rise. At six monitoring sites (Persian/Arabian Gulf, Red Sea, northern and southern Galápagos, Easter Island, Panama), over half of all corals were <31 years, implying that measured environmental variables indeed shaped populations and community. An Indo-Pacific-wide model suggests reefs in the northwest and central Indian Ocean, as well as the central west Pacific, are at highest risk of degradation, and those at high latitudes the least. The model pinpoints regions where coral reefs presently have the best chances for survival. However, reefs best buffered against temperature and nutrient effects are those that current studies suggest to be most at peril from future ocean acidification
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