807 research outputs found
The impact of primary production in the water column on benthic copepods
A phytoplankton bloom was followed from 9 March till 12 July 1999 at a subtidal station in the Southern Bight of the North Sea. Chla (in surface-, bottom- and interstitial water) and nutrient concentrations (interstitial water) as well as diatom biomass were measured in order to detect any deposition of organic material originating from the bloom on the bottom. The response of the benthic copepods to the sedimentation of the spring phytoplankton bloom was described in terms of changes in density, diversity and community structure. In March the bottom was already organically enriched, probably due to lateral transport. May and June were characterised by organic enrichment derived from the diatom and Phaeocystis spring bloom. In April and July no organic enrichment was observed. The changes in copepod density, diversity and community structure have been attributed to organic enrichment. Over the whole time series copepods were most abundant in the upper two centimetres of the sediment. Nevertheless, a migration of the copepods to the surface was observed during the organic enrichment. Individual species reacted differently to the spring bloom. Some species disappeared, others took advantage of the situation for reproduction. Most pronounced was the reaction of Apodopsyllus n. sp. 1 which was defined as an opportunistic species. The species composition along the sediment depth profile was very diverse in the months devoid of organic enrichment, in contrast with the months with organic enrichment, the community structure over the depth layers then being homogeneous
Using Bioenergetics and Radar-Derived Bird Abundance to Assess the Impact of a Blackbird Roost on Seasonal Sunflower Damage
Methods aimed at reducing avian damage to agricultural crops are routinely implemented in situations where efficacy can be assessed by quantifying blackbird (Icteridae) abundance relative to environmental variables and extrapolating to ensuing crop damage. Concomitantly, Weather Surveillance Radar (WSR) data may have potential to enhance crop damage mitigation through improved monitoring of nuisance wildlife populations. We used WSR to derive daily abundance estimates of blackbirds at a fall roost in North Dakota, USA from 2012 to 2019. We integrated these estimates with previously developed bioenergetics-economic models to estimate local sunflower (Helianthus annuus) damage. The greatest losses usually occurred during a brief period in October, when peak blackbird abundance coincided with large percentages (\u3e50%) of mature but unharvested sunflower fields. Most sunflower fields were harvested later than peak blackbird abundance (360,000–1,120,000 birds) and maximum daily damages (2,000 USD per day). This seasonal trend suggests advancing harvest time as a strategy to avoid the greatest losses in yield (up to $1,800 in savings at this 1 roost), which may be attainable by earlier planting of early-maturing crop varieties or crop desiccation
Marine aggregate extraction regulation in EU member states
This paper provides a brief review of regulations and procedures relevant to the authorization of marine aggregate (MA) operations in eight EU Member States. MA operations are affected by a multi-level legislative/regulatory regime, consisting of international conventions (e.g. the UNCLOS 1982, OSPAR, Helsinki, ICES, Barcelona and Espoo Conventions), secondary EC legislation (e.g. the Environmental Impact Assessment Directives (85/337/EEC and 97/11 EC) and the Freedom of Access to Environmental Information Directive (2003/4/EC)) and national legislation or regulation. It appears that rules and procedures relevant to MA extraction vary considerably between the considered Member States. In general, relevant information is not easily available in accurate, comprehensive and up-to date form. As a result, it is difficult to assess whether and to which extent national practice in relation to MA extraction authorization is in substantive compliance with the requirements of existing international and European rules and regulations aimed at sustainable development and protection of the marine and coastal environment
The 1.4 GHz Cosmic Star Formation History at z < 1.3
We measure the cosmic star formation history out to z = 1.3 using a sample of
918 radio-selected star forming galaxies within the 2 square degree COSMOS
field. To increase our sample size, we combine 1.4 GHz flux densities from the
VLA-COSMOS catalogue with flux densities measured from the VLA-COSMOS radio
continuum image at the positions of I < 26.5 galaxies, enabling us to detect
1.4 GHz sources as faint as 40 uJy. We find radio measurements of the cosmic
star formation history are highly dependent on sample completeness and models
used to extrapolate the faint end of the radio luminosity function. For our
preferred model of the luminosity function, we find the star formation rate
density increases from 0.019 Solar masses per year per cubic Mpc at z = 0.225
to 0.104 Solar masses per year per cubic Mpc, which agrees to within 33% of
recent UV, IR and 3 GHz measurements of the cosmic star formation history.Comment: 7 pages, 3 figures. Accepted for publication in Publications of the
Astronomical Society of Australi
Primary laminopathy fibroblasts display altered genome organization and apoptosis
A number of diseases associated with specific tissue degeneration and premature aging have mutations in the nuclear envelope proteins A-type lamins or emerin. Those diseases with A-type lamin mutation are inclusively termed laminopathies. Due to various hypothetical roles of nuclear envelope proteins in genome function we investigated whether alterations to normal genomic behaviour are apparent in cells with mutations in A-type lamins and emerin. Even though the distributions of these proteins in proliferating laminopathy fibroblasts appear normal, there is abnormal nuclear positioning of both chromosome 18 and 13 territories, from the nuclear periphery to the interior. This genomic organization mimics that found in normal nonproliferating quiescent or senescent cells. This finding is supported by distributions of modified pRb in the laminopathy cells. All laminopathy cell lines tested and an X-linked Emery-Dreifuss muscular dystrophy cell line also demonstrate increased incidences of apoptosis. The most extreme cases of apoptosis occur in cells derived from diseases with mutations in the tail region of the LMNA gene, such as Dunningan-type familial partial lipodystrophy and mandibuloacral dysplasia, and this correlates with a significant level of micronucleation in these cells
Randomised phase 3 study of adjuvant chemotherapy with or without nadroparin in patients with completely resected non-small-cell lung cancer: the NVALT-8 study
Contains fulltext :
207334.pdf (publisher's version ) (Open Access
Aspectos operativos del movimiento browniano y del proceso de ruido blanco
The aim of the present paper is the description of the way in which a stochastic process can be decomposed as a countable sum of orthogonal terms, and the application of such expansion to the brownian movement and to the white noise.El presente tnibajo tiene por objeto describir la forma en que puede descomponerse un proceso estocástico como suma numerable de componentes ortogonales, y aplicar dicho desarrollo a los procesos de movimiento browniano y de ruido blanco
Mathematical Properties of a New Levin-Type Sequence Transformation Introduced by \v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. I. Algebraic Theory
\v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la [J. Math. Phys. \textbf{44}, 962
- 968 (2003)] introduced in connection with the summation of the divergent
perturbation expansion of the hydrogen atom in an external magnetic field a new
sequence transformation which uses as input data not only the elements of a
sequence of partial sums, but also explicit estimates
for the truncation errors. The explicit
incorporation of the information contained in the truncation error estimates
makes this and related transformations potentially much more powerful than for
instance Pad\'{e} approximants. Special cases of the new transformation are
sequence transformations introduced by Levin [Int. J. Comput. Math. B
\textbf{3}, 371 - 388 (1973)] and Weniger [Comput. Phys. Rep. \textbf{10}, 189
- 371 (1989), Sections 7 -9; Numer. Algor. \textbf{3}, 477 - 486 (1992)] and
also a variant of Richardson extrapolation [Phil. Trans. Roy. Soc. London A
\textbf{226}, 299 - 349 (1927)]. The algebraic theory of these transformations
- explicit expressions, recurrence formulas, explicit expressions in the case
of special remainder estimates, and asymptotic order estimates satisfied by
rational approximants to power series - is formulated in terms of hitherto
unknown mathematical properties of the new transformation introduced by
\v{C}\'{\i}\v{z}ek, Zamastil, and Sk\'{a}la. This leads to a considerable
formal simplification and unification.Comment: 41 + ii pages, LaTeX2e, 0 figures. Submitted to Journal of
Mathematical Physic
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