1,166 research outputs found

    International Year of Planet Earth 5. Applications of Seafloor Mapping on the Canadian Atlantic Continental Shelf

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    Canada’s final mapping frontier is its offshore territory. Compared to Canada’s landmass, only a limited portion of Canada’s seafloor has been mapped using the modern technology of multi-beam sonar. Where this high-resolution mapping technique has been applied on Canada’s Atlantic continental margin, insight has been gained into the studies of seafloor habitat mapping, Quaternary history and sea-level change, sediment bedforms and dynamics, and seafloor conditions for in-stream tidal power. Seafloor habitat mapping in Canada provides the knowledge base to effectively manage offshore fisheries, evaluate marine protected areas, minimize the environmental impact of offshore development, and resolve seafloor-use conflicts. Multibeam sonar mapping has revealed a complex glacial landsystem developed on the Canadian Atlantic continental shelf and supports the concept of the late glacial maximum reaching the shelf edge. The application of multibeam sonar technology offers unprecedented images of bedform geomorphology and this knowledge is crucial to understanding sediment mobility and its effect on seafloor habitat, engineering, and infrastructure. To minimize the risk to engineering infrastructure on the seabed, planning of tidal-energy developments in regions of large tidal range requires detailed information about the water depth, seafloor substrate and sediment mobility, and long-term seabed change garnered using multibeam sonar mapping techniques. SOMMAIRE L’ultime frontière de la cartographie du Canada est son territoire extracôtier. Par rapport à son territoire continental, seule une faible portion du territoire extracôtier canadien a été cartographié par la technique moderne d’imagerie sonar multifaisceaux. Là où cette technique de cartographie de haute résolution a été utilisée sur la marge continentale canadienne atlantique, on a pu faire des progrès dans l’étude de cartographie d’habitat du fond marin, de l’histoire quaternaire des fluctuations du niveau de la mer, de la morphologie des couches et de la dynamique sédimentaires, ainsi que des caractéristiques du fond marin en vue de l’installation de centrales marémotrices. La cartographie d’habitat du fond marin permet de constituer une base de connaissances nécessaires pour gérer efficacement la pêche hauturière, établir la valeur des zones marines protégées, minimiser les incidences environ-nementales des activités de mise en valeur extracôtières, et résoudre les conflits d’utilisation des fonds marins. La cartographie par imagerie sonar multifaisceaux a montré qu’un système complexe de terres émergées s’est développé sur le plateau continental atlantique du Canada et qui correspond au concept d’un maximum glaciaire ayant atteint la limite du plateau continental. L’utilisation de la technologie sonar multifaisceaux permet d’obtenir des images sans précédents de la morphologie des dépôts, et ces connaissances sont cruciales pour comprendre la mobilité des sédiments et les répercussions sur l’habitat du fond marin, les aménagements et les infrastructures. Dans le but de minimiser les risques sur les infrastructures installées sur le fond marin, la planification d’installations marémotrices en zones de marées à grandes variations exige des informations détaillées sur la profondeur d’eau, la nature du fond marin et la mobilité des sédiments, ainsi que sur les changements à longs termes obtenues par l’utilisation de technique de cartographie sonar multifaisceaux

    Submarine glacial landforms on the Bay of Fundy–northern Gulf of Maine continental shelf

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    Author Posting. © The Author(s), 2016. This is the author's version of the work. It is posted here by permission of Geological Society of London for personal use, not for redistribution. The definitive version was published in Geological Society, London, Memoirs 46 (2016): 429-436, doi:10.1144/M46.154.The Bay of Fundy–northern Gulf of Maine region surrounds the southern part of Nova Scotia, encompassing, from west to east, the Bay of Fundy, Grand Manan Basin, German Bank, Browns Bank, Northeast Channel, and northeastern Georges Bank (Fig. 1a). During the last glacial maximum (~24–20 14C ka BP), the southeast margin of the Laurentide Ice Sheet (LIS) occupied the study area, the rest of the Gulf of Maine, and the continental Scotian Shelf off Atlantic Canada (see Dyke et al. 2002, Fig. 1; Hundert & Piper 2008, Fig. 16; Shaw et al. 2006, Fig. 8). Early mapping of the glaciated region on the Scotian Shelf using side-scan sonar imagery and seismic reflection profiles revealed topographic features interpreted to be recessional moraines indicative of retreat of the LIS (King et al. 1972; King 1996; Stea et al. 1998). Subsequently, multibeam sonar seafloor mapping of local-scale glacial landforms on the inner Scotian Shelf off Halifax, Nova Scotia (Fig. 1a) provided further information on the dynamics of the advance and retreat of the ice sheet (Loncarevic et al. 1994). Interpretation of seismic reflection profiles across Georges Bank revealed that the surficial sediment is a veneer of glacial debris transported to Georges Bank by the LIS during the late Pleistocene from continental areas to the north (Shepard et al. 1934; Knott & Hoskins 1968; Oldale & Uchupi 1970; Schlee 1973; Schlee & Pratt 1970; Twichell et al. 1987; Fader et al. 1988). Recent high-resolution multibeam sonar surveys of German Bank and the Bay of Fundy mapped a complex of ice-advance and ice-retreat features attributed to the activity of the LIS (Todd et al. 2007; Todd & Shaw 2012).2017-11-0

    The peri-urbanization of Europe:A systematic review of a multifaceted process

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    Urbanisation patterns in Europe since the 1950s have resulted in a swath of low-density discontinuous development, commonly called peri-urban areas. These areas are characterised by a mixed rural-urban character, are highly dynamic in nature, and are expected to continue growing rapidly in the next few decades. This paper presents a systematic review of the literature on changes in peri-urban areas in Europe. We analysed 142 cases from 121 studies that are spread across Europe, representing a wide range of peri-urban processes. Land cover changes were the most reported changes, followed by socioeconomic changes, land use changes, planning process changes, land management changes, and environmental changes. Over half of the cases reported co-occurring land-cover and socioeconomic processes of change. In addition, we analysed sequential and causal relations between these processes. In this analysis we found that peri-urbanization cannot be conceptualized as driver – land change – impact, because often relations between processes pointed in different directions. Therefore, we characterize peri-urbanization as a multifaceted process that can manifest itself differently in different case study areas. In addition, we found that planning precedes land change processes about as often as it follows these processes, illustrating the specific challenge for planners and policy makers in managing peri-urban areas

    Aspergillus nidulans ArfB Plays a Role in Endocytosis and Polarized Growth

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    Filamentous fungi undergo polarized growth throughout most of their life cycles. The Spitzenkörper is an apical organelle composed primarily of vesicles that is unique to filamentous fungi and is likely to act as a vesicle supply center for tip growth. Vesicle assembly and trafficking are therefore important for hyphal growth. ADP ribosylation factors (Arfs), a group of small GTPase proteins, play an important role in nucleating vesicle assembly. Little is known about the role of Arfs in filamentous hyphal growth. We found that Aspergillus nidulans is predicted to encode six Arf family proteins. Analysis of protein sequence alignments suggests that A. nidulans ArfB shares similarity with ARF6 of Homo sapiens and Arf3p of Saccharomyces cerevisiae. An arfB null allele (arfB disrupted by a transposon [arfB::Tn]) was characterized by extended isotropic growth of germinating conidia followed by cell lysis or multiple, random germ tube emergence, consistent with a failure to establish polarity. The mutant germ tubes and hyphae that do form initially meander abnormally off of the axis of polarity and frequently exhibit dichotomous branching at cell apices, consistent with a defect in polarity maintenance. FM4-64 staining of the arfB::Tn strain revealed that another phenotypic characteristic seen for arfB::Tn is a reduction and delay in endocytosis. ArfB is myristoylated at its N terminus. Green fluorescent protein-tagged ArfB (ArfB::GFP) localizes to the plasma membrane and endomembranes and mutation (ArfB(G2A)::GFP) of the N-terminal myristoylation motif disperses the protein to the cytoplasm rather than to the membranes. These results demonstrate that ArfB functions in endocytosis to play important roles in polarity establishment during isotropic growth and polarity maintenance during hyphal extension

    Digitalna procjena lisne površine krošnje stijenke vinove loze (Vitis vinifera cv. Sauvignon) korištenjem LIDAR mjerne tehnologije

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    A dosage rate reduction of plant protection products mixed with water, i.e. spray mixture, in a prescribed concentration in the vineyard will only be possible in the future, if the natural characteristics of vine canopy structures (leaf wall area) and canopy management are taken into account. In a practical experiment in the vineyard we evaluated the leaf wall area of the vine cv. Sauvignon on different segments on the left and right side of the vine canopy. We compared the results of manual measurements and laser measuring technology (LIDAR) with the corresponding algorithm, with which we enabled the digital reconstruction of the leaf wall area of the vine. The manual measurement of the leaf wall area was carried out using an automated image analyser. The digital system for measuring the leaf wall area on different segments consisted of a LIDAR sensor and a Differential Global Positioning System (hereinafter DGPS). To determine the exact DGPS position of the LIDAR sensor during the measurement, we set up a DGPS base station. Using the Excel software (CORREL function), we estimated the relationship between the dependent variable (digital number of points in the cloud) and an independent variable (leaf wall area, manually measured). An analysis of six randomly selected vines in the vineyard revealed the maximum value of the correlation coefficient r = 0.80 for the left side and r = 0.90 for the right side of the leaf wall area of the vine, respectively. In the near future the virtual three-dimensional space will provide more even control of spray mixture over the entire structure of the leaf wall area in the vineyard based on autonomous decision-making models.Smanjenje količine utroška sredstava za zaštitu bilja i same smjese za prskanje u budućnosti će biti moguće samo ako se uzmu u obzir prirodne karakteristike krošnje vinove loze tj. lisne površine krošnje trsa. U praktičnom pokusu u vinogradu procijenjena je lisna površinu krošnje vinove loze cv. Sauvignon na različitim segmentima s lijeve i desne strane krošnje uz pomoć ručnih mjerenja i laserske mjerne tehnologije (LIDAR). Dobiveni rezultati uspoređeni su s pripadajućim algoritmom čime je dobivena digitalna rekonstrukcija lisne površine vinove loze. Ručno mjerenje površine listova provedeno je u laboratoriju pomoću digitalnog lisnog skenera nakon što je lišće ručno pobrano s trsova i dopremljeno u sam laboratorij. Digitalni sustav za mjerenje lisne površine na različitim segmentima krošnje sastojao se od LIDAR senzora i DGPS navigacijskog sustava. Da bi se odredio točan DGPS položaj LIDAR senzora tijekom mjerenja, postavljena je DGPS bazna stanica. Pomoću regresijske metode utvrđen je odnos između zavisne varijable (digitalni broj točaka u oblaku) i nezavisne varijable (površina listova izmjerena skenerom). Rezultati analize imeđu dvije uspoređivane metode na šest slučajno odabranih trsova vinove loze otkrivaju vrijednost koeficijenta korelacije r = 0,80 za lijevu i r = 0,90 za desnu stranu krošnje. U bliskoj budućnosti virtualni trodimenzionalni prostor pružit će ravnomjerniju kontrolu smjese raspršivača preko cijele strukture područja stijenke lišča u vinogradu na temelju autonomnih modela odlučivanja

    Sampling Daphnia's expressed genes: preservation, expansion and invention of crustacean genes with reference to insect genomes

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    <p>Abstract</p> <p>Background</p> <p>Functional and comparative studies of insect genomes have shed light on the complement of genes, which in part, account for shared morphologies, developmental programs and life-histories. Contrasting the gene inventories of insects to those of the nematodes provides insight into the genomic changes responsible for their diversification. However, nematodes have weak relationships to insects, as each belongs to separate animal phyla. A better outgroup to distinguish lineage specific novelties would include other members of Arthropoda. For example, crustaceans are close allies to the insects (together forming Pancrustacea) and their fascinating aquatic lifestyle provides an important comparison for understanding the genetic basis of adaptations to life on land versus life in water.</p> <p>Results</p> <p>This study reports on the first characterization of cDNA libraries and sequences for the model crustacean <it>Daphnia pulex</it>. We analyzed 1,546 ESTs of which 1,414 represent approximately 787 nuclear genes, by measuring their sequence similarities with insect and nematode proteomes. The provisional annotation of genes is supported by expression data from microarray studies described in companion papers. Loci expected to be shared between crustaceans and insects because of their mutual biological features are identified, including genes for reproduction, regulation and cellular processes. We identify genes that are likely derived within Pancrustacea or lost within the nematodes. Moreover, lineage specific gene family expansions are identified, which suggest certain biological demands associated with their ecological setting. In particular, up to seven distinct ferritin loci are found in <it>Daphnia </it>compared to three in most insects. Finally, a substantial fraction of the sampled gene transcripts shares no sequence similarity with those from other arthropods. Genes functioning during development and reproduction are comparatively well conserved between crustaceans and insects. By contrast, genes that were responsive to environmental conditions (metal stress) and not sex-biased included the greatest proportion of genes with no matches to insect proteomes.</p> <p>Conclusion</p> <p>This study along with associated microarray experiments are the initial steps in a coordinated effort by the <it>Daphnia </it>Genomics Consortium to build the necessary genomic platform needed to discover genes that account for the phenotypic diversity within the genus and to gain new insights into crustacean biology. This effort will soon include the first crustacean genome sequence.</p

    IFN-Îł-producing CD4+ T cells promote experimental cerebral malaria by modulating CD8+ T cell accumulation within the brain.

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    It is well established that IFN-Îł is required for the development of experimental cerebral malaria (ECM) during Plasmodium berghei ANKA infection of C57BL/6 mice. However, the temporal and tissue-specific cellular sources of IFN-Îł during P. berghei ANKA infection have not been investigated, and it is not known whether IFN-Îł production by a single cell type in isolation can induce cerebral pathology. In this study, using IFN-Îł reporter mice, we show that NK cells dominate the IFN-Îł response during the early stages of infection in the brain, but not in the spleen, before being replaced by CD4(+) and CD8(+) T cells. Importantly, we demonstrate that IFN-Îł-producing CD4(+) T cells, but not innate or CD8(+) T cells, can promote the development of ECM in normally resistant IFN-Îł(-/-) mice infected with P. berghei ANKA. Adoptively transferred wild-type CD4(+) T cells accumulate within the spleen, lung, and brain of IFN-Îł(-/-) mice and induce ECM through active IFN-Îł secretion, which increases the accumulation of endogenous IFN-Îł(-/-) CD8(+) T cells within the brain. Depletion of endogenous IFN-Îł(-/-) CD8(+) T cells abrogates the ability of wild-type CD4(+) T cells to promote ECM. Finally, we show that IFN-Îł production, specifically by CD4(+) T cells, is sufficient to induce expression of CXCL9 and CXCL10 within the brain, providing a mechanistic basis for the enhanced CD8(+) T cell accumulation. To our knowledge, these observations demonstrate, for the first time, the importance of and pathways by which IFN-Îł-producing CD4(+) T cells promote the development of ECM during P. berghei ANKA infection
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