Interaksjoner mellom olje og miljøgifter i marine sediment

Hovedmålet med prosjektet var å avklare om tilstedeværelsen av olje i sediment vil påvirke bioakkumulering av miljøgifter fra dette sedimentet, fordeling av miljøgifter i sedimentet, utlekking av miljøgifter fra sedimentet og/eller ha effekter på sediment-levende organismer. Et underordnet mål var å kvantifisere betydningen av bioturbasjon for bioakkumulering, fordeling og utlekking av de valgte miljøgiftene, samt påvirkning av bioturbasjon på biologiske effekter av miljøgifter og/eller olje. Det ble benyttet to sediment-levende børstemark, en sediment-spiser og bioturberer (fjæremark Arenicola marina) og en altetende børstemark som ikke bioturberer vesentlig (Hediste diversicolor). I tillegg ble det satt blåskjell i små akvarier på utløpet fra hvert sedimentakvarium. Sedimentet i alle akvariene ble tilsatt miljøgifter (5 mg/kg Cd, 1 mg/kg TBT, 1 mg/kg PCB) og enten olje (3,7 /kg), alger (8.8 g/kg) eller intet. Forsøket varte i fire måneder. Tilstedeværelsen av olje i sedimentet reduserte akumulering av alle miljøgifter (Cd, TBT, PCB) i H. diversicolor. Mens tilsetning av alger ga økt akkumulering av Cd i fjæremark, var den ingen forskjeller mellom behandlingene med hensyn til akkumulering av organiske tinnforbindelser. Olje hadde ingen åpenbare effekter på vekst eller bioturbasjon i forhold til kontroll, men både vekst og bioturbasjon var høyere i akvarier med alge-tilsetning enn i de to andre behandlingene

Kartlegging av forurensningstilstanden i Meråker gruvefelt

Avrenning fra kisgruvene i Meråkerfeltet påvirker fortsatt vannkvaliteten i vassdragene i nedbørfeltet selv 100 år etter at gruvedriften opphørte. Største forurensningskilde i området er Lillefjell gruve som bidrar med ca. 80 % av kobbertilførslene til Stjørdalselva som er ca. 3 tonn på årsbasis. Gilsåa og Dalåa er mest belastet med tungmetaller, men vassdragsreguleringen som er foretatt, kan ha bidratt til en forverret vannkvalitet i Torsbjørka nedenfor inntaket til kraftverket. Undersøkelser av bunnfaunaen viser klare påvirkninger i Dalåa, mens det var en naturlig bunnfauna i nedre del av Torsbjørka og i Stjørdalselva. Burforsøk med ørret viste en høy dødelighet i Gilsåa/Dalåa. Det ble også påvist at ørreten i Torsbjørka var metallbelastet

Profile-Based Optimal Matchings in the Student-Project Allocation Problem

In the Student/Project Allocation problem (spa) we seek to assign students to individual or group projects offered by lecturers. Students provide a list of projects they find acceptable in order of preference. Each student can be assigned to at most one project and there are constraints on the maximum number of students that can be assigned to each project and lecturer. We seek matchings of students to projects that are optimal with respect to profile, which is a vector whose rth component indicates how many students have their rth-choice project. We present an efficient algorithm for finding agreedy maximum matching in the spa context – this is a maximum matching whose profile is lexicographically maximum. We then show how to adapt this algorithm to find a generous maximum matching – this is a matching whose reverse profile is lexicographically minimum. Our algorithms involve finding optimal flows in networks. We demonstrate how this approach can allow for additional constraints, such as lecturer lower quotas, to be handled flexibly

Biomarkers in monitoring - a review

Årsliste 2006Biological effects are increasingly used to monitor impacts of contaminants in marine ecosystems. Biomarkers have been defined as ”biochemical, cellular, physiological or behavioural variations in the tissue or body fluids or at the level of whole organism that provide evidence of exposure to chemical pollutants, and may also indicate a toxic effect”. The biomarkers reviewed here were PAH bile metabolites, cytochrome P4501A, glutathione S-transferase, markers for DNA damage (adducts, alkaline unwinding, Comet assay), micronucleus formation, peroxisomal proliferation, acetyl cholinesterase inhibition, metallothionein, vitellogenin and delta-aminolevulinic acid dehydratase. Focus for the review was dose-response relationships, confounding factors, links to population effects, baseline values, assessment criteria and quality assurance for the relevant biomarker. Whereas correlative links to population-relevant effects have been found for some biomarkers, e.g. biomarkers for DNA damage, most biomarkers are generally more useful as markers for possible impacts elsewhere in ecosystems.OL

Rank Maximal Matchings -- Structure and Algorithms

Let G = (A U P, E) be a bipartite graph where A denotes a set of agents, P denotes a set of posts and ranks on the edges denote preferences of the agents over posts. A matching M in G is rank-maximal if it matches the maximum number of applicants to their top-rank post, subject to this, the maximum number of applicants to their second rank post and so on. In this paper, we develop a switching graph characterization of rank-maximal matchings, which is a useful tool that encodes all rank-maximal matchings in an instance. The characterization leads to simple and efficient algorithms for several interesting problems. In particular, we give an efficient algorithm to compute the set of rank-maximal pairs in an instance. We show that the problem of counting the number of rank-maximal matchings is #P-Complete and also give an FPRAS for the problem. Finally, we consider the problem of deciding whether a rank-maximal matching is popular among all the rank-maximal matchings in a given instance, and give an efficient algorithm for the problem

Pareto Optimal Matchings in Many-to-Many Markets with Ties

We consider Pareto-optimal matchings (POMs) in a many-to-many market of applicants and courses where applicants have preferences, which may include ties, over individual courses and lexicographic preferences over sets of courses. Since this is the most general setting examined so far in the literature, our work unifies and generalizes several known results. Specifically, we characterize POMs and introduce the \emph{Generalized Serial Dictatorship Mechanism with Ties (GSDT)} that effectively handles ties via properties of network flows. We show that GSDT can generate all POMs using different priority orderings over the applicants, but it satisfies truthfulness only for certain such orderings. This shortcoming is not specific to our mechanism; we show that any mechanism generating all POMs in our setting is prone to strategic manipulation. This is in contrast to the one-to-one case (with or without ties), for which truthful mechanisms generating all POMs do exist

Social Welfare in One-Sided Matching Mechanisms

We study the Price of Anarchy of mechanisms for the well-known problem of one-sided matching, or house allocation, with respect to the social welfare objective. We consider both ordinal mechanisms, where agents submit preference lists over the items, and cardinal mechanisms, where agents may submit numerical values for the items being allocated. We present a general lower bound of $\Omega(\sqrt{n})$ on the Price of Anarchy, which applies to all mechanisms. We show that two well-known mechanisms, Probabilistic Serial, and Random Priority, achieve a matching upper bound. We extend our lower bound to the Price of Stability of a large class of mechanisms that satisfy a common proportionality property, and show stronger bounds on the Price of Anarchy of all deterministic mechanisms

Supporting variables for biological effects measurements in fish and blue mussels

Biological effects measurements in fish and blue mussel are fundamental in marine environmental monitoring. Nevertheless, currently used biomarkers may be confounded by basic physiological phenomena, such as growth, reproduction, and feeding, as well as thereby associated physiological variation. Here, we present a number of supporting variables, which are essential to measure in order to obtain reliable biological effects data, facilitate their interpretation, and make valid comparisons. For fish, these variables include: body weight, body length, condition, gonad maturation status, various somatic indices, age, and growth. For blue mussels, these variables include: volume, flesh weight, shell weight, and condition. Also, grossly visible anomalies, lesions, and parasites should be recorded for both fish and blue mussels. General confounding factors and their effects are described, as well as recommendations for how to handle themPostprint

A multibiomarker approach highlights effects induced by the human pharmaceutical gemfibrozil to gilthead seabream Sparus aurata

Lipid regulators are among the most prescribed human pharmaceuticals worldwide. Gemfibrozil, which belongs to this class of pharmaceuticals, is one of the most frequently encountered in the aquatic environment. However, there is limited information concerning the mechanisms involved in gemfibrozil effects to aquatic organisms, particularly to marine organisms. Based on this knowledge gap, the current study aimed to assess biochemical and behavioral effects following a sublethal exposure to gemfibrozil (1.5, 15, 150, 1500 and 15,000 μg L-1) in the estuarine/marine fish Sparus aurata. After the exposure to 1.5 μg L-1 of gemfibrozil, fish had reduced ability to swim against a water flow and increased lipid peroxidation in the liver. At concentrations between 15-15,000 μg L-1, the activities of some enzymes involved in antioxidant defense were induced, appearing to be sufficient to prevent oxidative damage. Depending on the organ, different responses to gemfibrozil were displayed, with enzymes like catalase being more stimulated in gills, whereas glutathione peroxidase was more activated in liver. Although there were no obvious concentration-response relationships, the integrated biomarker response version 2 (IBRv2) analysis revealed that the highest concentrations of gemfibrozil (between 150-15,000 μg L-1) caused more alterations. All the tested concentrations of gemfibrozil induced effects in S. aurata, in terms of behavior and/or oxidative stress responses. Oxidative damage was found at a concentration that is considered environmentally relevant, suggesting a potential of this pharmaceutical to impact fish populations.This research was supported through the COMPETE – Operational Competitiveness Program and National Funds through FCT – Foundation for Science and Technology, under the project “NANOAu – Effects of Gold Nanoparticles to Aquatic Organisms” (FCT PTDC/MAR-EST/3399/2012) (FCOMP-01-0124-FEDER-029435), through FCT/MCTES through national funds (PIDDAC), the cofounding by FEDER, within the PT2020 Partnership Agreement and Compete 2020 to CESAM (UID/AMB/50017 – POCI-01-0145-FEDER-007638) and UID/QUI/50006/2013. A. Barreto has a doctoral fellowship from FCT (SFRH/BD/97624/2013); L. G. Luis had a fellowship from FCT (BI/UI88/6881/2014). MO has financial support of the program Investigator FCT, co-funded by the Human Potential Operational Programme and European Social Fund (IF/00335(2015).info:eu-repo/semantics/publishedVersio