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1.
Variability in the performance of juvenile Chinook salmon is explained primarily by when and where they resided in estuarine habitats 下载免费PDF全文
Paul Chittaro Lyndal Johnson David Teel Paul Moran Sean Sol Kate Macneale Richard Zabel 《Ecology of Freshwater Fish》2018,27(3):857-873
Estuarine habitats provide rearing opportunities for the juvenile life stage of anadromous fishes. Because survival is positively correlated with juvenile performance, these estuarine habitats play an important role in population abundance and productivity. To provide information for the recovery of several depressed stocks of Chinook salmon in the Columbia River Basin, we sought to identify the factors that explain variability in performance. Using otolith‐derived estimates of juvenile somatic growth rate as an index of recent performance, we observed a negative nonlinear relationship between growth rate and day of year, and a decreasing and increasing trend of growth rate over the 8 years of this study and distance from the river mouth respectively. Using a generalised linear modelling approach, we found that variability in juvenile somatic growth rate was best explained by where and when individuals were collected, their body size, contaminant loads, stock of origin, and whether a fish was hatchery produced or unmarked. Lastly, we argue that a considerable improvement to the growth rate of juveniles in estuarine habitats is physiologically possible. The results of this 8‐year study provide a baseline of the performance of juvenile Chinook salmon to evaluate habitat restoration programs and to compare against future anthropogenic conditions. 相似文献
2.
Pim Lindhout Wanda Korta Jeanne Dijkstra 《European journal of plant pathology / European Foundation for Plant Pathology》1988,94(6):307-310
Samenvatting Een methode werd ontwikkeld om de resistentie van in de kas geteelde tomateplanten tegen tomatemozaïek virus (ToMV) te bepalen. Bladeren van een vatbare en een resistente cultivar werden afgesneden en geïnoculeerd met ToMV. Na 6, 10 en 17 dagen werden de geïnoculeerde bladeren getoetst op de aanwezigheid van virus met ELISA en door inoculatie van bladeren vanNicotiana glutinosa. Met beide toetsmethoden kon de virustoename in de vatbare cultivar al vroeg na inoculatie duidelijk worden aangetoond. In de bladeren van de resistente cultivar was een zeer kleine hoeveelheid virus pas laat na de inoculatie aantoonbaar. Met deze methode is het mogelijk om de resistentie tegen ToMV te bepalen, tevens zaad te winnen en landbouwkundige eigenschappen te evalueren, zonder de plant te infecteren. 相似文献
3.
Summary The early growth of 96 genotypes of tomato was studied at 320 ppm CO2 and at 750 ppm CO2 in separate climate rooms. Plants were harvested at 40 and 55 days after sowing. Fresh and dry weights were determined. Large differences between genotypes were found for average plant fresh and dry weights and for relative growth rates. The average overall growth enhancement by CO2 enrichment was 2.3. Two genotypes showed significant genotype x CO2 interaction. The consequences of these results for tomato breeding are discussed. 相似文献
4.
Total lipid extracts from an acid andic soil profile located on Madeira Island (Portugal) were analysed using gas chromatography (GC) and GC-mass spectrometry (GC/MS). The profile was covered mainly by grass. Bulk soil characteristics determined included soil pH (H2O) ranging from 4.5 to 4.0 and TOC, ranging from 84 to 30 g kg−1. A decrease of the contribution of lipids per TOC with depth was observed. The absence of typical bacterial markers might be an indication for reduced bacterial activity, most likely related to the low soil pH and the presence of Al and Fe (oxides). The distribution observed in the top layer with a dominant C26n-alkanol, steroids and triterpenoids, reflected mainly an input by grass leaves. A strong decrease in both relative and absolute concentration of these leaf-derived compounds was observed when comparing the litter layer with the mineral soil. The presence of C22-C32n-alkanoic acids, C22-C26 ω-hydroxy acids, C31n-alkane and C22-C32n-alkanols observed in the sub-soil is indicative of an important contribution by (grass) roots. In summer, a signal most likely reflecting the leaching of microbially derived products from the litter and/or aerial vegetation at the surface was observed. 相似文献
5.
Dorn RI Bamforth DB Cahill TA Dohrenwend JC Turrin BD Donahue DJ Jull AJ Long A Macko ME Weil EB Whitley DS Zabel TH 《Science (New York, N.Y.)》1986,231(4740):830-833
The first accelerator radiocarbon dates of rock varnishes are reported along with potassium/argon ages of lava flows and conventional radiocarbon dates of pluvial lake shorelines, in an empirical calibration of rock varnish K(+) + Ca(2+)/Ti(4+) ratios with age in the Mojave Desert, eastern California. This calibration was used to determine the cation-ratio dates of 167 artifacts. Although cation-ratio dating is an experimental method, some dates suggest human occupation of the Mojave Desert in the late Pleistocene. 相似文献
6.
Hinrichs W Büttner G Steifa M Betzel C Zabel V Pfannemüller B Saenger W 《Science (New York, N.Y.)》1987,238(4824):205-208
In the crystal structure of the polyiodide complex (p-nitrophenyl-alpha-maltohexaose(2)) . Ba(I(3))(2) . 22H(2)O, the maltohexaose units form an antiparallel, left-handed double helix with O-2 ... O-3 and O-6 ... O-6 hydrogen bonding and a central cavity that encloses two triiodide units. This structure contrasts with the parallel, left-handed double helix with no central cavity proposed for the A-and B-starch helix and the left-handed single helix in V-amylose and may be relevant for the stabilization of glycogen Structure. 相似文献
7.
Immune responses in chickens to Eimeria tenella using oral and subcutaneous routes of infection were investigated. The results obtained indicated that sporulated oocysts inoculated subcutaneously in doses up to 50 000 oocysts per bird were not fatal to 21-day-old chicks. Subcutaneous inoculation of oocysts was found to be less immunogenic than oral administration. The dynamics of the antibody responses were different for the two routes of infection. Orally administered oocysts stimulated a dramatic primary increase in the serum antibody titre with a tendency towards a decrease in the titre 14 days post infection irrespective of second infections at that time. However, a third oral dose of oocysts stimulated a slight increase in antibody titre. Two doses of oocysts injected subcutaneously induced only a slight increase in serum antibody titre. Such a low titre was dramatically increased following a subsequent oral dose of oocysts. Antibodies specific to E. tenella are IgM and IgG immunoglobulins. IgA immunoglobulin was not investigated. 相似文献
8.
9.
Comparative evaluation of six different body regions of the dog using analog and digital radiography
Meyer-Lindenberg A Ebermaier C Wolvekamp P Tellhelm B Meutstege FJ Lang J Hartung K Fehr M Nolte I 《Berliner und Münchener tier?rztliche Wochenschrift》2008,121(5-6):216-227
In this study the quality of digital and analog radiography in dogs was compared. For this purpose, three conventional radiographs (varying in exposure) and three digital radiographs (varying in MUSI-contrast [MUSI = MUlti Scale Image Contrast], the main post-processing parameter) of six different body regions of the dog were evaluated (thorax, abdomen, skull, femur, hip joints, elbow). The quality of the radiographs was evaluated by eight veterinary specialists familiar with radiographic images using a questionnaire based on details of each body region significant in obtaining a radiographic diagnosis. In the first part of the study the overall quality of the radiographs was evaluated. Within one region, 89.5% (43/48) chose a digital radiograph as the best image. Divided into analog and digital groups, the digital image with the highest MUSI-contrast was most often considered the best, while the analog image considered the best varied between the one with the medium and the one with the longest exposure time. In the second part of the study, each image was rated for the visibility of specific, diagnostically important details. After summarisation of the scores for each criterion, divided into analog and digital imaging, the digital images were rated considerably superior to conventional images. The results of image comparison revealed that digital radiographs showed better image detail than radiographs taken with the analog technique in all six areas of the body. 相似文献
10.
Pim Lindhout Dennis Meijer Theo Schotte Ronald C. B. Hutten Richard G. F. Visser Herman J. van Eck 《Potato Research》2011,54(4):301-312
Compared to other major food crops, progress in potato yield as the result of breeding efforts is very slow. Genetic gains
cannot be fixed in potato due to obligatory out-breeding. Overcoming inbreeding depression using diploid self-compatible clones
should enable to replace the current method of out-breeding and clonal propagation into an F1 hybrid system with true seeds. This idea is not new, but has long been considered unrealistic. Severe inbreeding depression
and self-incompatibility in diploid germplasm have hitherto blocked the development of inbred lines. Back-crossing with a
homozygous progenitor with the Sli gene which inhibits gametophytic self-incompatibility gave self-compatible offspring from elite material from our diploid
breeding programme. We demonstrate that homozygous fixation of donor alleles is possible, with simultaneous improvement of
tuber shape and tuber size grading of the recipient inbred line. These results provide proof of principle for F1 hybrid potato breeding. The technical and economic perspectives are unprecedented as these will enable the development of
new products with combinations of useful traits for all stakeholders in the potato chain. In addition, the hybrid’s seeds
are produced by crossings, rendering the production and voluminous transport of potato seed tubers redundant as it can be
replaced by direct sowing or the use of healthy mini-tubers, raised in greenhouses. 相似文献