5,668 research outputs found
Trophic capacity of Carlingford Lough for oyster culture – analysis by ecological modelling
A one-dimensional
ecosystem box model is presented for carrying capacity assessment.The model includes physical
and biological processes. The physical processes are the transport of nutrients, suspended matter and phytoplankton
through the system boundaries and between model boxes. The biological processes are primary production and
oyster (Crassostrea gigas) population dynamics and physiology. The model was implemented using an object oriented
approach. The model was employed to estimate the carrying capacity of Carlingford Lough (Ireland) for
oyster culture. In the Lough, low water temperatures prevent the oysters from reproducing. Therefore, recruitment
is human dependent.
Small oyster spat is seeded every year during spring and harvested after the summer of the
next year. During this period oysters reach commercially harvestable weight. The results obtained indicate that the
carrying capacity of this system is approximately 0.45 g oysters (AFDW) m-3, determined more by the availability
of particulate matter than by phytoplankton. It is suggested that a fivefold
increase in oyster seeding may optimise
harvest yield
Trophic capacity of Carlingford Lough for oyster culture – analysis by ecological modelling
A one-dimensional
ecosystem box model is presented for carrying capacity assessment.The model includes physical
and biological processes. The physical processes are the transport of nutrients, suspended matter and phytoplankton
through the system boundaries and between model boxes. The biological processes are primary production and
oyster (Crassostrea gigas) population dynamics and physiology. The model was implemented using an object oriented
approach. The model was employed to estimate the carrying capacity of Carlingford Lough (Ireland) for
oyster culture. In the Lough, low water temperatures prevent the oysters from reproducing. Therefore, recruitment
is human dependent.
Small oyster spat is seeded every year during spring and harvested after the summer of the
next year. During this period oysters reach commercially harvestable weight. The results obtained indicate that the
carrying capacity of this system is approximately 0.45 g oysters (AFDW) m-3, determined more by the availability
of particulate matter than by phytoplankton. It is suggested that a fivefold
increase in oyster seeding may optimise
harvest yield
Stability of neutral minima against charge breaking in the Higgs triplet model
We analyse the possibility of charge breaking minima developing in the Higgs triplet model, and under what conditions they are deeper than charge-preserving ones. Analytical expressions relating the depth of minima of different types are deduced. A global symmetry of the model leads to increased stability for charge-preserving vacua. However, if that symmetry is broken by a soft term, deeper charge-breaking minima may occur more easily. We identify the vev configurations most likely to produce charge breaking minima.info:eu-repo/semantics/publishedVersio
Iris-Fixated Intraocular Lenses for Ametropia and Aphakia
Implantation of intraocular lens with Iris-fixation is a safe, efficient and predictable surgical procedure, which empowers the refractive surgeon with singular capabilities. Among their advantages are the reversibility, preservation of accommodation and a broad spectrum of ametropic correction. This lens also appears to be a valid option, with a favorable complication rate, for the treatment of aphakic eyes without capsular support. This article is a review of iris-fixated intraocular lenses and considers their principal indications, complications, and outcomes
Characterization of a rare analphoid supernumerary marker chromosome in mosaic
Abstract publicado em: Chromosome Research. 2015;23(Suppl 1):67-8. doi:10.1007/s10577-015-9476-6Analphoid supernumerary marker chromosomes (SMCs) are a rare subclass of SMCs C-band-negative
and devoid of alpha-satellite DNA. These marker chromosomes cannot be identified unambiguously by conventional banding techniques alone being necessary to apply molecular cytogenetic methods in favour of a detailed characterization. In this work we report an analphoid SMC involving the terminal long arm of chromosome 7, in 9 years-old boy with several dysmorphic features and severe development delay.
Cytogenetic analysis revealed a mosaic karyotype with the presence of an extra SMC, de novo, in 20 %
of lymphocytes and 73 % of fibroblast cells. FISH analysis with alpha-satellite probes for all chromosomes, whole chromosome painting probe for chromosome 7, and D7S427 and TelVysion 7q probes, allowed
establishing the origin of the SMC as an analphoidmarker resulting of an invdup rearrangement of 7q36-qter region. Affimetrix CytoScan HD microarray analysis, redefined the SMC to arr[hg19] 7q35(143696249-159119707)×2~3, which correspond to a gain of 15.42 Mb and encloses 67 OMIM genes, 16 of which are associated to disease. This result, combined with detailed clinical description, will provide an important means for better genotype-phenotype correlation and a more suitable genetic counselling to the patient and his parents, despite the additional difficulty resulting from being a mosaic (expression varies in different tissues). Analphoid SMCs derived from chromosome 7 are very rare, with only three cases reported so far. With this case we hope contribute to a better understanding of this type of chromosome rearrangements which are difficult for genetic counselling
HDPE geogrid-residual soil interaction under monotonic and cyclic pullout loading
The understanding of soil-geosynthetic interaction under cyclic loading conditions is essential for the safe design of geosynthetic-reinforced soil structures subjected to repeated loads, such as those induced by road and railway traffic and earthquakes. This paper describes a series of large-scale monotonic and multistage pullout tests carried out to investigate the behaviour of an HDPE uniaxial geogrid embedded in a locally available granite residual soil under monotonic and cyclic pullout loading. The effects of the pullout load level at the start of the cyclic stage, cyclic load frequency and amplitude, number of cycles and soil density on the load-strain-displacement response of the reinforcement are evaluated and discussed. Test results show that the cumulative displacements measured along the length of the geogrid during cyclic loading increased significantly with the precyclic pullout load level and the load amplitude. In contrast, the cumulative cyclic displacements were found to decrease with increasing frequency and soil density. In medium dense soil conditions, the geogrid post-cyclic pullout resistance decreased by up to 20%, with respect to the value obtained in the comparable monotonic test. However, for dense soil, the effect of cyclic loading on the peak pullout forces recorded during the tests was almost negligible
Particles’ distribution enhancing in aluminum-based composites produced by upward friction stir processing
Funding Information: Open access funding provided by FCT|FCCN (b-on). CV and TGS acknowledge Fundação para a Ciência e a Tecnologia (FCT-MCTES) for its financial support via projects UIDB/00667/2020 and UIDP/00667/2020 (UNIDEMI). PMF also acknowledges FCT-MCTES for its financial support via the PhD scholarship UI/BD/151055/2021. PLI would like to acknowledge FCT-MCTES for its financial support via the PhD scholarship FCT-SFRH /BD/146885/2019. RJCS acknowledges national funds from FCT-MCTES, in the scope of the project UIDB/50025/2020–2023 of the CENIMAT/i3N. Publisher Copyright: © 2023, The Author(s).A new variant of friction stir processing named upward friction stir processing (UFSP) is a promising approach to control particles’ distribution and promote a more uniform distribution over a larger processed area. This variant involves using two sheets with functional particles between them to produce metallic composites. A spacer is used to ensure the desired quantity and uniform distribution of the particles and prevent sputtering. This technique promotes an upward flow to introduce more particles with a uniform distribution in the processed volume, avoiding discrete holes or grooves. This study involved enhancing the particles’ distribution by varying process parameters. The resulting trial with the best particles’ distribution was characterized by means of light microscopy, eddy current testing, microhardness mapping, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The study revealed that UFSP can improve the particles’ distribution in the stir zone of metallic composites, especially when multi-passes are performed towards the retreating side of the plates. The process parameters that produced an improvement in particles’ distribution were six passes with an offset of 1 mm towards the retreating side, the tool rotation and processing speed of 900 rev/min, and 180 mm/min, respectively, and a spacer’s thickness of 0.5 mm. The resulting hardness and electrical conductivity profiles show that the UFSP technique can significantly affect material’s properties, including mechanical strength, particularly when processing with tool offset towards the retreating side. Furthermore, the hardness increased by about 22% in composites produced with the addition of reinforcement particles. However, for some aluminum alloys, the properties decreased under such conditions. These findings highlight the potential of UFSP for producing functionalized materials with tailored properties, while also underscoring the importance of careful parameters selection to optimize the material´s performance. Graphical Abstract: [Figure not available: see fulltext.].publishersversioninpres
A Review of Orbital Friction Stir Welding
Funding Information: The authors acknowledge the Portuguese Agência Nacional de Inovação (ANI), trough the project SI I&DT (PROJETOS MOBILIZADORES), Nº 024534-“INFANTE-Microssatélite para Vigilância Marítima, Observação da Terra e IoT no contexto de constelações”, co-financed by PORTUGAL2020, through Fundo Europeu de Desenvolvimento Regional (FEDER). Authors acknowledge the Portuguese Fundação para a Ciência e a Tecnologia (FCT–MCTES) for its financial support via the project UID/EMS/00667/2019 (UNIDEMI). Authors acknowledge funding by national funds from FCT-Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020, UIDP/50025/2020 and UIDB/50025/2020 of the Associate Laboratory Institute of Nanostructures, Nanomodelling and Nanofabrication–i3N. Publisher Copyright: © 2023 by the authors.Friction stir welding is a solid-state joining process widely used in several industrial applications. One of its variants, orbital friction stir welding, is of key importance in fundamental industries such as oil and gas and aerospace. For orbital friction stir welding, there is a need to develop not only new process parameters but also tools and ancillary mechanisms that can ensure sound, high-performing joints are obtained. This review assesses the current state of orbital friction stir welding, highlighting several key aspects related to this technology.publishersversionpublishe
Foreground Subtraction in Intensity Mapping with the SKA
21cm intensity mapping experiments aim to observe the diffuse neutral
hydrogen (HI) distribution on large scales which traces the Cosmic structure.
The Square Kilometre Array (SKA) will have the capacity to measure the 21cm
signal over a large fraction of the sky. However, the redshifted 21cm signal in
the respective frequencies is faint compared to the Galactic foregrounds
produced by synchrotron and free-free electron emission. In this article, we
review selected foreground subtraction methods suggested to effectively
separate the 21cm signal from the foregrounds with intensity mapping
simulations or data. We simulate an intensity mapping experiment feasible with
SKA phase 1 including extragalactic and Galactic foregrounds. We give an
example of the residuals of the foreground subtraction with a independent
component analysis and show that the angular power spectrum is recovered within
the statistical errors on most scales. Additionally, the scale of the Baryon
Acoustic Oscillations is shown to be unaffected by foreground subtraction.Comment: This article is part of the 'SKA Cosmology Chapter, Advancing
Astrophysics with the SKA (AASKA14), Conference, Giardini Naxos (Italy), June
9th-13th 2014
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