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71.
This paper presents a general, process-based mass balance model (CoastMab) for total phosphorus (TP) in defined coastal areas
(at the ecosystem scale). The model is based on ordinary differential equations and calculates inflow, outflow and internal
fluxes on a monthly basis. It consists of four compartments: surface water, deep water, erosion/transportation areas for fine
sediments and accumulation areas for fine sediments. The separation between surface water and deep water is not done based
on water temperature, but on sedimentological criteria instead (from the theoretical wave base). There are algorithms for
all major internal TP fluxes (sedimentation, resuspension, diffusion, mixing and burial). Validations were performed using
data from 21 different Baltic coastal areas. The results show that the model predicts monthly TP in water and chlorophyll a very well (generally within the uncertainty bands of the empirical data). The model has also been put through sensitivity
tests, which show that the most important factor regulating the predictions of the model is generally the TP concentration
in the sea beyond the coast. The model is simple to apply, since all driving variables may be accessed from maps or monitoring
programs. The driving variables include coastal area, section area (between the defined coastal area and the adjacent sea),
mean and maximum depths, latitude (used to predict water temperatures, stratification and mixing), salinity and TP concentration
in the sea. Many of the model structures are general and could be used for areas other than those included in this study,
e.g., for open coasts, estuaries or tidal coasts, as well as for other substances than phosphorus. 相似文献
72.
Erling S. Nordøy Lars P. Folkow Vladimir Potelov Vitaly Prischemikhin Arnoldus Schytte Blix 《Polar Biology》2008,31(9):1119-1135
Eight adult female harp seals (Pagophilus
groenlandicus) of the White Sea–Barents Sea stock were tagged with satellite-linked dive recorders during the nursing period and followed
from breeding in late February 1995 until moulting in late April 1995. Another ten adult harp seals of both sexes were tagged
and followed from moult in early May 1996 until breeding in late February the following year. Between breeding and moult the
seals were distributed along the coasts of Kola of Russia and eastern Finnmark of Norway, coinciding in time and space with
the spawning capelin (Mallotus villosus). Between moulting and breeding they encircled the entire Barents Sea, mostly in open water, using the water column from
20 to 300 m, and in so doing by and large reflecting the annual migrations of the capelin. Capelin is therefore assumed to
be the main source of prey for the White Sea–Barents Sea stock of harp seals, to be substituted, in part, by amphipods (e.g.
Themisto libellula) in mid-summer and polar cod (Boreogadus saida) and herring (Clupea pallasii) in late autumn and winter. These data provide a baseline for the evaluation of the effects of future climatic change in
the rich Barents Sea ecosystem. 相似文献
73.
The -amino group of the carbohydrate-binding module (CBM) from Phanerochaete chrysosporium cellulase Cel7D was covalently labelled with fluorescein isothiocyanate. The fluorescein-labelled CBM was characterised regarding substrate binding, showing specificity only to cellulose and not to mannan and xylan. Conjugation of fluorescein isothiocyanate to CBM did not affect its binding to cellulose. The labelled CBM was successfully used as a probe for detecting cellulose in lignocellulose material such as never dried spruce and birch wood as well as pulp fibres. 相似文献
74.
Brain Cell Biology - Cytochemical techniques were used to study the localization of 5′-nucleotidase in the enteric ganglia and in smooth muscle cells of the guinea-pig ileum, iris and vas... 相似文献
75.
Floral scents of male and female inflorescences of three dioeciousSalix species were collected by head-space adsorption, and analysed by GC-MS. InSalix caprea andS. cinerea 1,4-dimethoxy benzene was the main compound, and male and female scents showed a high degree of resemblance. No dominant compound was found inS. repens and malefemale scent similarity was low. Floral scent inSalix is likely a strong orientation cue, guiding pollinators between male and female plants ensuring pollen transfer and pollination. We suggest that a high degree of male-female floral scent resemblance is coupled to a high degree of insect pollination. Floral scent does not promote reproductive isolation betweenS. caprea andS. cinerea. 相似文献
76.
Two-tier vessels, developed for culturing of microalgae and cyanobacteria at high cell density on a shaken platform, were assembled from a flat lower chamber to be filled with a CO2 buffer and an upper flat sterile chamber for the culture that was separated from the lower chamber by a porous polypropylene membrane. Diffusive gas exchange with the atmosphere was controlled by the O2 outlet channel. Referred to surface area, rates of CO2 transfer to a shaken weakly alkaline buffer solution across the membrane were higher than those reached on the conventional pathway through the free upper liquid surface. Membrane-mediated CO2 supply enabled rapid growth of Synechocystis sp. PCC 6803 and Synechococcus sp. PCC 7002 up to ultrahigh cell density. The biomass (dry weight) concentration of Synechococcus cultures reached more than 30 g L?1 on a buffered medium with adequate concentrations of mineral nutrients. An increase of 15 to 20 g L?1 was observed during repeated two-day cycles. Separate pathways for CO2 supply and oxygen outlet prevented significant loss of CO2. Convective gas flow through the oxygen outlet channel enabled the estimation of the O2 generation rate. The permeability of the channel for diffusive O2/N2 exchange limited the O2 concentration to a moderate value. It is concluded that shaken flat cultures using CO2 supply through a porous hydrophobic membrane and diffusive release of O2 through a separate pathway are promising for research on microalgae and cyanobacteria. 相似文献
77.
Lars Michels Kerstin Bucher Rafael Lüchinger Peter Klaver Ernst Martin Daniel Jeanmonod Daniel Brandeis 《PloS one》2010,5(4)
Background
EEG studies of working memory (WM) have demonstrated load dependent frequency band modulations. FMRI studies have localized load modulated activity to the dorsolateral prefrontal cortex (DLPFC), medial prefrontal cortex (MPFC), and posterior parietal cortex (PPC). Recently, an EEG-fMRI study found that low frequency band (theta and alpha) activity negatively correlated with the BOLD signal during the retention phase of a WM task. However, the coupling of higher (beta and gamma) frequencies with the BOLD signal during WM is unknown.Methodology
In 16 healthy adult subjects, we first investigated EEG-BOLD signal correlations for theta (5–7 Hz), alpha1 (8–10), alpha2 (10–12 Hz), beta1 (13–20), beta2 (20–30 Hz), and gamma (30–40 Hz) during the retention period of a WM task with set size 2 and 5. Secondly, we investigated whether load sensitive brain regions are characterised by effects that relate frequency bands to BOLD signals effects.Principal Findings
We found negative theta-BOLD signal correlations in the MPFC, PPC, and cingulate cortex (ACC and PCC). For alpha1 positive correlations with the BOLD signal were found in ACC, MPFC, and PCC; negative correlations were observed in DLPFC, PPC, and inferior frontal gyrus (IFG). Negative alpha2-BOLD signal correlations were observed in parieto-occipital regions. Beta1-BOLD signal correlations were positive in ACC and negative in precentral and superior temporal gyrus. Beta2 and gamma showed only positive correlations with BOLD, e.g., in DLPFC, MPFC (gamma) and IFG (beta2/gamma). The load analysis revealed that theta and—with one exception—beta and gamma demonstrated exclusively positive load effects, while alpha1 showed only negative effects.Conclusions
We conclude that the directions of EEG-BOLD signal correlations vary across brain regions and EEG frequency bands. In addition, some brain regions show both load sensitive BOLD and frequency band effects. Our data indicate that lower as well as higher frequency brain oscillations are linked to neurovascular processes during WM. 相似文献78.
79.
Riccardo E. Marioni Lars Penke Gail Davies Jennifer E. Huffman Caroline Hayward Ian J. Deary 《Proceedings. Biological sciences / The Royal Society》2014,281(1781)
Human cognitive ability shows consistent, positive associations with fitness components across the life-course. Underlying genetic variation should therefore be depleted by selection, which is not observed. Genetic variation in general cognitive ability (intelligence) could be maintained by a mutation–selection balance, with rare variants contributing to its genetic architecture. This study examines the association between the total number of rare stop-gain/loss, splice and missense exonic variants and cognitive ability in childhood and old age in the same individuals. Exome array data were obtained in the Lothian Birth Cohorts of 1921 and 1936 (combined N = 1596). General cognitive ability was assessed at age 11 years and in late life (79 and 70 years, respectively) and was modelled against the total number of stop-gain/loss, splice, and missense exonic variants, with minor allele frequency less than or equal to 0.01, using linear regression adjusted for age and sex. In both cohorts and in both the childhood and late-life models, there were no significant associations between rare variant burden in the exome and cognitive ability that survived correction for multiple testing. Contrary to our a priori hypothesis, we observed no evidence for an association between the total number of rare exonic variants and either childhood cognitive ability or late-life cognitive ability. 相似文献
80.
Hanne Marie B?e Lunde Wenche Telstad Nina Grytten Lars Kyte Jan Aarseth Kjell-Morten Myhr Lars B? 《PloS one》2014,9(7)