793 research outputs found

    Tiltaksplan for forurensede sedimenter i Aust-Agder. Fase 1 - Miljøtilstand,

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    Rapporten omhandler første fase av tiltaksplan for forurensede sedimenter i Aust-Agder. De tre utvalgte områdene i Aust-Agder er Tvedestrand på innsiden av Sagesund, Arendal havneområde med Tromøysund og Vikkilen i Grimstad. I dette arbeidet er det gjort en gjennomgang av eksisterende data med kartpresentasjon av miljøstatus for de ulike miljøgiftene i hvert tiltaksområde. Videre er det gitt en oversikt over aktuelle og mulige kilder til forurensning i nedbørfeltet og høyrisikoområder er foreslått. Data fra indre Tvedestrandsfjord har vist høye konsentrasjoner av både PAH og TBT (tilstandsklasse IV-V) slik at flere grunne områder er definert som mulige høyrisikoområder. Det er imidlertid behov for å ta prøver i grunne farvann for å kunne fastslå dette. I Arendal er spesielt havneområdene og området rundt Eydehavn forurenset av miljøgifter, men også småbåthavner og andre områder er sterkt forurenset. I likhet med Tvedestrand er det også her lite data fra grunne områder som er mest utsatt for spredning. Indre del av Vikkilen er foreslått som høyrisikoområde på grunn av høye PAH-verdier og ekstremt høye TBT-verdier. Det er behov for å ta prøver som verifiserer nivåene og gir opplysning om omfang

    A Call to Arms: Revisiting Database Design

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    Good database design is crucial to obtain a sound, consistent database, and - in turn - good database design methodologies are the best way to achieve the right design. These methodologies are taught to most Computer Science undergraduates, as part of any Introduction to Database class. They can be considered part of the "canon", and indeed, the overall approach to database design has been unchanged for years. Moreover, none of the major database research assessments identify database design as a strategic research direction. Should we conclude that database design is a solved problem? Our thesis is that database design remains a critical unsolved problem. Hence, it should be the subject of more research. Our starting point is the observation that traditional database design is not used in practice - and if it were used it would result in designs that are not well adapted to current environments. In short, database design has failed to keep up with the times. In this paper, we put forth arguments to support our viewpoint, analyze the root causes of this situation and suggest some avenues of research.Comment: Removed spurious column break. Nothing else was change

    Arachnoid cysts do not contain cerebrospinal fluid: A comparative chemical analysis of arachnoid cyst fluid and cerebrospinal fluid in adults

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    <p>Abstract</p> <p>Background</p> <p>Arachnoid cyst (AC) fluid has not previously been compared with cerebrospinal fluid (CSF) from the same patient. ACs are commonly referred to as containing "CSF-like fluid". The objective of this study was to characterize AC fluid by clinical chemistry and to compare AC fluid to CSF drawn from the same patient. Such comparative analysis can shed further light on the mechanisms for filling and sustaining of ACs.</p> <p>Methods</p> <p>Cyst fluid from 15 adult patients with unilateral temporal AC (9 female, 6 male, age 22-77y) was compared with CSF from the same patients by clinical chemical analysis.</p> <p>Results</p> <p>AC fluid and CSF had the same osmolarity. There were no significant differences in the concentrations of sodium, potassium, chloride, calcium, magnesium or glucose. We found significant elevated concentration of phosphate in AC fluid (0.39 versus 0.35 mmol/L in CSF; <it>p </it>= 0.02), and significantly reduced concentrations of total protein (0.30 versus 0.41 g/L; <it>p </it>= 0.004), of ferritin (7.8 versus 25.5 ug/L; <it>p </it>= 0.001) and of lactate dehydrogenase (17.9 versus 35.6 U/L; <it>p </it>= 0.002) in AC fluid relative to CSF.</p> <p>Conclusions</p> <p>AC fluid is not identical to CSF. The differential composition of AC fluid relative to CSF supports secretion or active transport as the mechanism underlying cyst filling. Oncotic pressure gradients or slit-valves as mechanisms for generating fluid in temporal ACs are not supported by these results.</p

    Oljeforurensning i sedimentene utenfor Sjursøya Oljehavn. 2002

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    Årsliste 2003Sedimentene utenfor Sjursøya er sterkt forurenset av olje, konsentrasjonene er like høye eller høyere i dag sammenlignet med undersøkelsene i 1993. Andelen NPD (oljerelatert PAH) var høyere i dag enn i 1993. Konsentrasjonen av sumPAH var noe lavere enn i 1993. Undersøkelsene tyder på at sedimentene kontinuerlig mottar olje fra Sjursøya eller nærliggende landområde. Den høye konsentrasjonen av olje i sedimentene utenfor Sjursøya kan ikke forklares med spredning fra sterkt forurensede sedimenter i inder deler av Oslo havn. Det er ikke sannsynlig at en reduksjon i oljeforurensning vil føre til noen bedring av en generelt forurensningsbelastet bunnfauna i området. De forurensede sedimentene ligger på dypt vann (>30 m) og med unntak av området nærmest kaia er de utsatt for lite forstyrrelse. Før en vurderer eventuelle tiltak på bunnsedimentene må tilførslene fra land stoppes eller reduseres betydelig.Oslo kommune Havnevesenet v/NG

    Kittelsbukta, Arendal. Miljøgifter i sedimenter, vurdering av risiko og tiltak.

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    Årsliste 2007I forbindelse med mulig utfylling for planlagt kaiutbygging i Kittelsbukt, Arendal er det gjennomført en undersøkelse av miljøtilstanden i bunnsedimentene i området. Sedimentene bestod av sand og grus, og hadde konsentrasjoner av metaller, spesielt kobber og kvikksølv, i forurensningsklasse II til V (moderat til meget sterkt forurenset), PCB i klasse III til V (markert til meget sterkt forurenset) og PAH og TBT i klasse IV og V (sterkt til meget sterkt forurenset). Sedimenter fra sandfangkummer oppstrøms Kittelsbukt var mindre forurenset. Avrenning herfra er derfor neppe kilden til forurensning i sjøen. Ut fra en risikovurdering utgjør sedimentene en uakseptabel risiko både for human helse og for økosystemet, og det bør utarbeides lokal tiltaksplan. Skråningen langs land hvor kaiutbyggingen skal foregå er fjell. For å hindre oppvirvling av de utenforliggende sedimentene under anlegg anbefales tildekking ut til 5-10 m foran kaifront. Ved peling vil lokal tildekking være tilstrekkelig, men hel tildekking anbefales. Ved utfylling anbefales hel tildekking med fiberduk og sandlag. Kilden til svært høy PAH som ble påvist i et lite område ytterst i bukta, bør identifiseres og stoppes. Ved gjennomføring av den fylkesvise tiltaksplanen anbefales det at man vurderer tynnsjiktstildekking utenfor det aktuelle anleggsområdet.St Ybes AS v/Hanne Smedal Sørense

    Asymptotics of the solutions of the stochastic lattice wave equation

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    We consider the long time limit theorems for the solutions of a discrete wave equation with a weak stochastic forcing. The multiplicative noise conserves the energy and the momentum. We obtain a time-inhomogeneous Ornstein-Uhlenbeck equation for the limit wave function that holds both for square integrable and statistically homogeneous initial data. The limit is understood in the point-wise sense in the former case, and in the weak sense in the latter. On the other hand, the weak limit for square integrable initial data is deterministic

    A comparison of ancient deltaic shoreline progradation with modern deltaic progradation rates: Unravelling the temporal structure of the shallow-marine Blackhawk Formation, Upper Cretaceous Western Interior Seaway, USA

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    Understanding how sedimentary rocks represent time is one of the significant challenges in sedimentology. Sedimentation rates retrieved from vertical sections are strongly timescale dependent, which means that we cannot use empirical rate data derived from vertical sections in modern environments to interpret the temporal structure of ancient sedimentary deposits. We use the Lower to Middle Campanian Blackhawk Formation deposits in eastern Utah and western Colorado as a natural laboratory to test a source-to-sink methodology circumventing this timescale dependence by relating modern progradation rates to the deltaic shoreline progradation of ancient siliciclastic rocks. Our objective is to quantify how much time is needed to account for the observed cumulative deltaic shoreline progradation recorded by the shallow-marine sandstone bodies of the Blackhawk Formation in terms of progradation rates derived from comparable modern deltaic systems. By making the simplifying assumption that the Blackhawk Formation rocks were deposited along a linear coastline that only grew by aggradation and progradation, it is possible to argue that the stratigraphic completeness of two-dimensional dip-oriented stratigraphic cross-sections through these deposits should be high. Furthermore, we hypothesise that delta progradation estimates capture a significant portion of the biostratigraphically and radiometrically constrained duration of the succession. By comparing the recorded progradation with modern progradation rates, we estimate that we need ca. 20% (median value, with minimum and maximum estimates of 2% and 300%) of the time available from biostratigraphic and radiometric dating to account for the progradation recorded by the sedimentary deposits. This indicates that long-term progradation rates averaged over the entire duration of the Blackhawk Formation were only a factor of five times slower than the modern progradation rates derived from observations over periods that are five to six orders of magnitude shorter. We conclude that a significant amount of time is represented by prograding deltaic shoreline deposits and that by considering the cumulative shoreline progradation, we could limit the effects of timescale dependence on the rate estimates used in our analysis

    Tyrosine and phenylalanine supplementation on Diplodus sargus larvae: effect on growth and quality

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    27 páginas, 3 figuras, 5 tablas. The definitive version is available at www.blackwell-synergy.comPhenylalanine is the precursor of tyrosine, which is involved in the synthesis of several molecules with key roles in the regulation of metabolism and growth, stress response and pigmentation. In this study, three experimental diets were tested: an amino acid (AA) balanced diet supplemented with phenylalanine, another supplemented with phenylalanine and tyrosine and a non-supplemented AA balanced diet. Rotifers were enriched with liposomes encapsulating free AA in order to obtain a balanced AA profile. The experimental diets resulted in similar larval survival, growth, enzyme activities of AA catabolism and nitrogen excretion in all treatments. High levels of skeletal deformities were registered and significant differences were found between the control and the phenylalanine treatment for the percentage of vertebral compressions in the trunk region of the vertebral column (30% in the control and 5% in the phenylalanine group). A significantly higher survival to a temperature stress test was found for larvae fed the diet supplemented with phenylalanine and tyrosine. The results suggest that supplementation of phenylalanine/tyrosine in fish diets may be useful in order to reduce skeletal deformities and mortalities caused by stress. The present study confirms that AA requirements may be sufficient for covering growth and survival but insufficient to cover other metabolic processes.This work was supported by the project POCI/MAR/61623/2004 – SAARGO, financed by the programme POCI 2010 (FCT, Portugal), which is co-financed by FEDER. FEDER and PN Project AGL2004-06669-C02-01 (Ministry of Education and Science, Spain) are co-financed by FEDER and project –‘Tecnologias de Produção Aquícola’– (22-05-01-FBR-00014 – QCA IIII).Peer reviewe
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