Tandem use of solid-phase extraction and dispersive liquid-liquid microextraction for the determination of mononitrotoluenes in aquatic environment.

Solid-phase extraction (SPE) in tandem with dispersive liquid-liquid microextraction (DLLME) has been developed for the determination of mononitrotoluenes (MNTs) in several aquatic samples using gas chromatography-flame ionization (GC-FID) detection system. In the hyphenated SPE-DLLME, initially MNTs were extracted from a large volume of aqueous samples (100 mL) into a 500-mg octadecyl silane (C(18) ) sorbent. After the elution of analytes from the sorbent with acetonitrile, the obtained solution was put under the DLLME procedure, so that the extra preconcentration factors could be achieved. The parameters influencing the extraction efficiency such as breakthrough volume, type and volume of the elution solvent (disperser solvent) and extracting solvent, as well as the salt addition, were studied and optimized. The calibration curves were linear in the range of 0.5-500 μg/L and the limit of detection for all analytes was found to be 0.2 μg/L. The relative standard deviations (for 0.75 μg/L of MNTs) without internal standard varied from 2.0 to 6.4% (n=5). The relative recoveries of the well, river and sea water samples, spiked at the concentration level of 0.75 μg/L of the analytes, were in the range of 85-118%.

Born to be bee, fed to be worker? The caste system of a primitively eusocial insect.

ABSTRACT: INTRODUCTION: Primitively eusocial halictid bees are excellent systems to study the origin of eusociality, because all individuals have retained the ancestral ability to breed independently. In the sweat bee Halictus scabiosae, foundresses overwinter, establish nests and rear a first brood by mass-provisioning each offspring with pollen and nectar. The mothers may thus manipulate the phenotype of their offspring by restricting their food provisions. The first brood females generally help their mother to rear a second brood of males and gynes that become foundresses. However, the first brood females may also reproduce in their maternal or in other nests, or possibly enter early diapause. Here, we examined if the behavioural specialization of the first and second brood females was associated with between-brood differences in body size, energetic reserves and pollen provisions. RESULTS: The patterns of variation in adult body size, weight, fat content and food provisioned to the first and second brood indicate that H. scabiosae has dimorphic females. The first-brood females were significantly smaller, lighter and had lower fat reserves than the second-brood females and foundresses. The first-brood females were also less variable in size and fat content, and developed on homogeneously smaller pollen provisions. Foundresses were larger than gynes of the previous year, suggesting that small females were less likely to survive the winter. CONCLUSIONS: The marked size dimorphism between females produced in the first and second brood and the consistently smaller pollen provisions provided to the first brood suggest that the first brood females are channelled into a helper role during their pre-imaginal development. As a large body size is needed for successful hibernation, the mother may promote helping in her first brood offspring by restricting their food provisions. This pattern supports the hypothesis that parental manipulation may contribute to promote worker behaviour in primitively eusocial halictids.

La dénervation rénale unilatérale et le système kallikréine-bradykinine rénal chez le rat [Unilateral renal denervation and the renal kallikrein-bradykinin system in the rat].

AIM: The antihypertensive effect of renal denervation in hypertensive patients is partially explained by increased tubular natriuresis. To study the possible contribution of the kallikrein-kinin system (KKS) to this natriuretic effect in rats, we measured kallikrein activity (KA) and bradykinin concentrations (BK) in plasma and tissues. METHODS: To measure KA, we adapted and validated an enzymatic assay that cleaves para-nitroaniline (pNA) from the tripeptide H-D-Pro-Phe-Arg-pNA. The coefficients of variation (CV) within- and between-assays were less than 8% for plasma and tissue KA (plasma n=6 and 13; tissue n=4). Linear results for serially diluted samples confirmed the assay specificity. Tissue BK determinations were based on an established assay for plasma BK: tissue was homogenized and kinins extracted in ethanol, and BK was isolated by high-performance (HPLC) liquid chromatography and quantitated by radioimmunassay. Within- and between-assay CV for plasma BK were 18% (n=8 and n=35, respectively) and for BK in various tissues less than 16% (n=5-8). RESULTS: In male Wistar rats (n=3), plasma BK was 8.2±6.6 fmol/mL (mean±SD), and tissue BK (fmol/g) in 14 tested organs varied between brain (14±3) and submaxillary gland (521±315). Six days after left-sided unilateral renal denervation, left renal tissue BK (89±9) was not different from right renal BK (75±23). Similarly, KA was comparable in the two kidneys (left 18.0±1.5, right 15.8±1.4μkat/g). CONCLUSION: Any possible effect of unilateral renal denervation on the kidney's KKS would have to be bilateral.

Social organization and mating system of free-ranging, greater white-toothed shrews, Crocidura russula

Indirect evidence from trapping suggests that Crocidura russula is less solitary and territorial than other shrews. To study the social organization and mating system, free-ranging adult and juvenile C. russula were tracked simultaneously throughout the year using a radioactive tracking technique. Coincident rest, coincident activity and home range overlap were measured. During winter, all individuals used the same communal nest and spent on average 84% of their total rest in coincident rest. This led to a large home range overlap (52% on average). Coincident activity was low (2% on average). At the onset of the reproductive season the females became, territorial and shared their nest with only one male. During pair formation, coincident activity and home range overlap were significantly greater between than within sexes. The social organization of C. russula appeared to be strongly influenced by season and differed in this respect from the other species in the genus Sorex which are territorial throughout the year.

Clinical Proton MR Spectroscopy in Central Nervous System Disorders.

A large body of published work shows that proton (hydrogen 1 [(1)H]) magnetic resonance (MR) spectroscopy has evolved from a research tool into a clinical neuroimaging modality. Herein, the authors present a summary of brain disorders in which MR spectroscopy has an impact on patient management, together with a critical consideration of common data acquisition and processing procedures. The article documents the impact of (1)H MR spectroscopy in the clinical evaluation of disorders of the central nervous system. The clinical usefulness of (1)H MR spectroscopy has been established for brain neoplasms, neonatal and pediatric disorders (hypoxia-ischemia, inherited metabolic diseases, and traumatic brain injury), demyelinating disorders, and infectious brain lesions. The growing list of disorders for which (1)H MR spectroscopy may contribute to patient management extends to neurodegenerative diseases, epilepsy, and stroke. To facilitate expanded clinical acceptance and standardization of MR spectroscopy methodology, guidelines are provided for data acquisition and analysis, quality assessment, and interpretation. Finally, the authors offer recommendations to expedite the use of robust MR spectroscopy methodology in the clinical setting, including incorporation of technical advances on clinical units. © RSNA, 2014 Online supplemental material is available for this article.

Equivalence of piecewise-linear approximation and Lagrangian relaxation for network revenue management

The network revenue management (RM) problem arises in airline, hotel, media,and other industries where the sale products use multiple resources. It can be formulatedas a stochastic dynamic program but the dynamic program is computationallyintractable because of an exponentially large state space, and a number of heuristicshave been proposed to approximate it. Notable amongst these -both for their revenueperformance, as well as their theoretically sound basis- are approximate dynamic programmingmethods that approximate the value function by basis functions (both affinefunctions as well as piecewise-linear functions have been proposed for network RM)and decomposition methods that relax the constraints of the dynamic program to solvesimpler dynamic programs (such as the Lagrangian relaxation methods). In this paperwe show that these two seemingly distinct approaches coincide for the network RMdynamic program, i.e., the piecewise-linear approximation method and the Lagrangianrelaxation method are one and the same.

The TetR-type MfsR protein of the integrative and conjugative element (ICE) ICEclc controls both a putative efflux system and initiation of ICE transfer.

Integrative and conjugating elements (ICE) are self-transferable DNAs widely present in bacterial genomes, which often carry a variety of auxiliary genes of potential adaptive benefit. One of the model ICE is ICEclc, an element originally found in Pseudomonas knackmussii B13 and known for its propensity to provide its host with the capacity to metabolize chlorocatechols and 2-aminophenol. In this work, we studied the mechanism and target of regulation of MfsR, a TetR-type repressor previously found to exert global control on ICEclc horizontal transfer. By using a combination of ICEclc mutant and transcriptome analysis, gene reporter fusions, and DNA binding assays, we found that MfsR is a repressor of both its own expression and that of a gene cluster putatively coding for a major facilitator superfamily efflux system on ICEclc (named mfsABC). Phylogenetic analysis suggests that mfsR was originally located immediately adjacent to the efflux pump genes but became displaced from its original cis target DNA by a gene insertion. This resulted in divergence of the original bidirectional promoters into two separated individual regulatory units. Deletion of mfsABC did not result in a strong phenotype, and despite screening a large number of compounds and conditions, we were unable to define the precise current function or target of the putative efflux pump. Our data reconstruct how the separation of an ancestor mfsR-mfsABC system led to global control of ICEclc transfer by MfsR.

On the throughput-WIP trade-off in queueing systems, diminishing returns and the threshold property: A linear programming approach

We present a new unifying framework for investigating throughput-WIP(Work-in-Process) optimal control problems in queueing systems,based on reformulating them as linear programming (LP) problems withspecial structure: We show that if a throughput-WIP performance pairin a stochastic system satisfies the Threshold Property we introducein this paper, then we can reformulate the problem of optimizing alinear objective of throughput-WIP performance as a (semi-infinite)LP problem over a polygon with special structure (a thresholdpolygon). The strong structural properties of such polygones explainthe optimality of threshold policies for optimizing linearperformance objectives: their vertices correspond to the performancepairs of threshold policies. We analyze in this framework theversatile input-output queueing intensity control model introduced byChen and Yao (1990), obtaining a variety of new results, including (a)an exact reformulation of the control problem as an LP problem over athreshold polygon; (b) an analytical characterization of the Min WIPfunction (giving the minimum WIP level required to attain a targetthroughput level); (c) an LP Value Decomposition Theorem that relatesthe objective value under an arbitrary policy with that of a giventhreshold policy (thus revealing the LP interpretation of Chen andYao's optimality conditions); (d) diminishing returns and invarianceproperties of throughput-WIP performance, which underlie thresholdoptimality; (e) a unified treatment of the time-discounted andtime-average cases.

Implementing TURF analysis through binary linear programming

This paper introduces the approach of using Total Unduplicated Reach and Frequency analysis (TURF) to design a product line through a binary linear programming model. This improves the efficiency of the search for the solution to the problem compared to the algorithms that have been used to date. The results obtained through our exact algorithm are presented, and this method shows to be extremely efficient both in obtaining optimal solutions and in computing time for very large instances of the problem at hand. Furthermore, the proposed technique enables the model to be improved in order to overcome the main drawbacks presented by TURF analysis in practice.

Proving the performance of a new revenue management system

Revenue management (RM) is a complicated business process that can best be described ascontrol of sales (using prices, restrictions, or capacity), usually using software as a tool to aiddecisions. RM software can play a mere informative role, supplying analysts with formatted andsummarized data who use it to make control decisions (setting a price or allocating capacity fora price point), or, play a deeper role, automating the decisions process completely, at the otherextreme. The RM models and algorithms in the academic literature by and large concentrateon the latter, completely automated, level of functionality.A firm considering using a new RM model or RM system needs to evaluate its performance.Academic papers justify the performance of their models using simulations, where customerbooking requests are simulated according to some process and model, and the revenue perfor-mance of the algorithm compared to an alternate set of algorithms. Such simulations, whilean accepted part of the academic literature, and indeed providing research insight, often lackcredibility with management. Even methodologically, they are usually awed, as the simula-tions only test \within-model" performance, and say nothing as to the appropriateness of themodel in the first place. Even simulations that test against alternate models or competition arelimited by their inherent necessity on fixing some model as the universe for their testing. Theseproblems are exacerbated with RM models that attempt to model customer purchase behav-ior or competition, as the right models for competitive actions or customer purchases remainsomewhat of a mystery, or at least with no consensus on their validity.How then to validate a model? Putting it another way, we want to show that a particularmodel or algorithm is the cause of a certain improvement to the RM process compared to theexisting process. We take care to emphasize that we want to prove the said model as the causeof performance, and to compare against a (incumbent) process rather than against an alternatemodel.In this paper we describe a \live" testing experiment that we conducted at Iberia Airlineson a set of flights. A set of competing algorithms control a set of flights during adjacentweeks, and their behavior and results are observed over a relatively long period of time (9months). In parallel, a group of control flights were managed using the traditional mix of manualand algorithmic control (incumbent system). Such \sandbox" testing, while common at manylarge internet search and e-commerce companies is relatively rare in the revenue managementarea. Sandbox testing has an undisputable model of customer behavior but the experimentaldesign and analysis of results is less clear. In this paper we describe the philosophy behind theexperiment, the organizational challenges, the design and setup of the experiment, and outlinethe analysis of the results. This paper is a complement to a (more technical) related paper thatdescribes the econometrics and statistical analysis of the results.

Breeding system and genetic variance in the monogamous, semi-social shrew, Crocidura russula

The population-genetic consequences of monogamy and male philopatry (a rare breeding system in mammals) were investigated using microsatellite markers in the semisocial and anthropophilic shrew Crocidura russula. A hierarchical sampling design over a 16-km geographical transect revealed a large genetic diversity (h = 0.813) with significant differentiation among subpopulations (F-ST = 5-6%), which suggests an exchange of 4.4 migrants per generation. Demic effective-size estimates were very high, due both to this limited gene inflow and to the inner structure of subpopulations. These were made of 13-20 smaller units (breeding groups), comprising an estimate of four breeding pairs each. Members of the same breeding groups displayed significant coancestries (F-LS = 9-10%), which was essentially due to strong male kinship: syntopic males were on average related at the half-sib level. Female dispersal among breeding groups was not complete (similar to 39%), and insufficient to prevent inbreeding. From our results, the breeding strategy of C. russula seems less efficient than classical mammalian systems (polygyny and male dispersal) in disentangling coancestry from inbreeding, but more so in retaining genetic variance.

Assessment of speed of human locomotion using a differential satellite global positioning system.

PURPOSE: The objective was to explore whether a satellite-based navigation system, global positioning system used in differential mode (DGPS), could accurately assess the speed of running in humans. METHODS: A subject was equipped with a portable GPS receptor coupled to a receiver for differential corrections, while running outdoors on a straight asphalt road at 27 different speeds. Actual speed (reference method) was assessed by chronometry. RESULTS: The accuracy of speed prediction had a standard deviation (SD) of 0.08 km x h(-1) for walking, 0.11 km x h(-1) for running, yielding a coefficient of variation (SD/mean) of 1.38% and 0.82%, respectively. There was a highly significant linear relationship between actual and DGPS speed assessment (r2 = 0.999) with little bias in the prediction equation, because the slope of the regression line was close to unity (0.997). CONCLUSION: the DGPS technique appears to be a valid and inconspicuous tool for "on line" monitoring of the speed of displacement of individuals located on any field on earth, for prolonged periods of time and unlimited distance, but only in specific environmental conditions ("open sky"). Furthermore, the accuracy of speed assessment using the differential GPS mode was improved by a factor of 10 as compared to non-differential GPS.

Trophic dynamics in the northern Humboldt Current system: insights from stable isotopes and stomach content analyses

The northern Humboldt Current system (NHCS) off Peru is one of the most productive world marine regions. It represents less than 0.1% of the world ocean surface but presently sustains about 10% of the world fish catch, with the Peruvian anchovy or anchoveta Engraulis ringens as emblematic fish resource. Compared with other eastern boundary upwelling systems, the higher fish productivity of the NHCS cannot be explained by a corresponding higher primary productivity. On another hand, the NHCS is the region where El Niño, and climate variability in general, is most notable. Also, surface oxygenated waters overlie an intense and extremely shallow Oxygen Minimum Zone (OMZ). In this context, the main objective of this study is to better understand the trophic flows in the NHCS using both stomach content and stable isotope analyses. The study focuses on a variety of organisms from low trophic levels such as zooplankton to top predators (seabirds and fur seals). The approach combines both long-term and specific studies on emblematic species such as anchoveta, and sardine Sardinops sagax and a more inclusive analysis considering the 'global' food web in the recent years (2008 – 2012) using stable isotope analysis. Revisiting anchovy and sardine we show that whereas phytoplankton largely dominated anchoveta and sardine diets in terms of numerical abundance, the carbon content of prey items indicated that zooplankton was by far the most important dietary component. Indeed for anchovy euphausiids contributed 67.5% of dietary carbon, followed by copepods (26.3%). Selecting the largest prey, the euphausiids, provide an energetic advantage for anchoveta in its ecosystem where oxygen depletion imposes strong metabolic constrain to pelagic fish. Sardine feed on smaller zooplankton than do anchoveta, with sardine diet consisting of smaller copepods and fewer euphausiids than anchoveta diet. Hence, trophic competition between sardine and anchovy in the northern Humboldt Current system is minimized by their partitioning of the zooplankton food resource based on prey size, as has been reported in other systems. These results suggest an ecological role for pelagic fish that challenges previous understanding of their position in the foodweb (zooplanktophagous instead of phytophagous), the functioning and the trophic models of the NHCS. Finally to obtain a more comprehensive vision of the relative trophic position of NHCS main components we used stable isotope analyses. For that purpose we analyzed the δ13C and δ15N stable isotope values of thirteen taxonomic categories collected off Peru from 2008 - 2011, i.e., zooplankton, fish, squids and air-breathing top predators. The δ15N isotope signature was strongly impacted by the species, the body length and the latitude. Along the Peruvian coast, the OMZ get more intense and shallow south of ~7.5ºS impacting the baseline nitrogen stable isotopes. Employing a linear mixed-effects modelling approach taking into account the latitudinal and body length effects, we provide a new vision of the relative trophic position of key ecosystem components. Also we confirm stomach content-based results on anchoveta Engraulis ringens and highlight the potential remarkable importance of an often neglected ecosystem component, the squat lobster Pleuroncodes monodon. Indeed, our results support the hypothesis according to which this species forage to some extent on fish eggs and larvae and can thus predate on the first life stages of exploited species. However, the δ13C values of these two species suggest that anchoveta and squat lobster do not exactly share the same habitat. This would potentially reduce some direct competition and/or predation.

Molecular evolution of the Drosophila olfactory system

The olfactory system is an attractive model to study the genetic mechanisms underlying evolution of the nervous system. This sensory system mediates the detection and behavioural responses to an enormous diversity of volatile chemicals in the environment and displays rapid evolution, as species acquire, modify and discard olfactory receptors and circuits to adapt to new olfactory stimuli. Drosophilids provide an attractive model to study these processes. The availability of 12 sequenced genomes of Drosophila species occupying diverse ecological niches provides a rich resource for genomic analyses. Moreover, one of these species, Drosophila melanogaster, is amenable to a powerful combination of genetic and electrophysiological analyses. D. melanogaster has two distinct families of olfactory receptors to detect odours, the well-characterised Odorant Receptors (ORs) and the recently identified lonotropic Receptors (IRs). In my thesis, I have provided new insights into the genetic mechanisms underlying olfactory system evolution through three distinct, but interrelated projects. First, I performed a comparative genomic analysis of the IR repertoire in 12 sequenced Drosophila species, which has revealed that the olfactory IRs are highly conserved across species. By contrast, a large fraction of IRs that are not expressed in the olfactory system - and which may be gustatory receptors - are much more variable in sequence and gene copy number. Second, to identify ligands for IR expressing olfactory sensory neurons, I have performed an electrophysiological screen in D. melanogaster using a panel of over 160 odours. I found that the IRs respond to a number of amines, aldehydes and acids, contrasting with the chemical specificity of the OR repertoire, which is mainly tuned to esters, alcohols and ketones. Finally, the identification of ligands for IRs in this species allowed me to investigate in detail the molecular and functional evolution of a tandem array of IRs, IR75a/IR75b/IR75c, in D. sechellia. This species is endemic to the Seychelles archipelago and highly specialised to breed on the fruits of Morinda citrifolia, which is repulsive and toxic for other Drosophila species. These studies led me to discover that receptor loss, changes in receptor specificity and changes in receptor expression have likely played an important role during the evolution of these IRs in D. sechellia. These changes may explain, in part, the unique chemical ecology of this species. - Le système olfactif est un excellent modèle pour étudier les mécanismes génétiques impliqués dans l'étude de l'évolution du système nerveux. Ce système sensoriel permet la détection de nombreux composés volatils présents dans l'environnement et est à la base des réponses comportementales. Il est propre à chaque espèce et évolue rapidement en modifiant ou en éliminant des récepteurs et leurs circuits olfactifs correspondants pour s'adapter à de nouvelles odeurs. Pour étudier le système olfactif et son évolution, nous avons décidé d'utiliser la drosophile comme modèle. Le séquençage complet de 12 souches de drosophiles habitant différentes niches écologiques permet une analyse génomique conséquente. De plus, l'une de ces espèces Drosophila melanogaster permet la combinaison d'analyses génétiques et électrophysiologiques. En effet, D. melanogaster possède 2 familles distinctes de récepteurs olfactifs qui permettent la détection d'odeurs: les récepteurs olfactifs (ORs) étant les mieux caractérisés et les récepteurs ionotropiques (IRs), plus récemment identifiés. Au cours de ma thèse, j'ai apporté des nouvelles connaissances qui m'ont permis de mieux comprendre les mécanismes génétiques à la base de l'évolution du système olfactif au travers de trois projets différents, mais interdépendants. Premièrement, j'ai réalisé une analyse génomique comparative de l'ensemble des IRs dans les 12 souches de drosophiles séquencées jusqu'à présent. Ceci a montré que les récepteurs olfactifs IRs sont hautement conservés parmi l'ensemble de ces espèces. Au contraire, une grande partie des IRs qui ne sont pas exprimés dans le système olfactif, et qui semblent être des récepteurs gustatifs, sont beaucoup plus variables dans leur séquence et dans le nombre de copie de gènes. Deuxièmement, pour identifier les ligands des récepteurs IRs exprimés par les neurones sensoriels olfactifs, j'ai réalisé une étude électrophysiologique chez D. melanogaster e η testant l'effet de plus de 160 composés chimiques sur les IRs. J'ai trouvé que les IRs répondent à un nombre d'amines, d'aldéhydes et d'acides, contrairement aux récepteurs olfactifs ORs qui eux répondent principalement aux esthers, alcools et cétones. Finalement, l'identification de ligands pour les IRs dans ces espèces m'a permis d'étudier en détail l'évolution fonctionnelle et moléculaire des IR75a/IR75b/IR75c dans D. sechellia. Cette espèce est endémique de l'archipel des Seychelles et se nourrit spécifiquement du fruit Morinda citrifolia qui est répulsif et toxique pour d'autres souches de drosophiles. Ces études m'ont poussé à découvrir que, la perte de IR75a, le changement dans la spécificité de IR75b ainsi que le changement dans l'expression de IR75c ont probablement joué un rôle important dans l'évolution des IRs chez D. sechellia. Ces changements peuvent expliquer, en partie, l'écologie chimique propre à cette espèce. Résumé français large public Le système olfactif permet aux animaux de détecter des milliers de molécules odorantes, les aidant ainsi à trouver de la nourriture, à distinguer si elle est fraîche ou avariée, à trouver des partenaires sexuels, ainsi qu'à éviter les prédateurs. Selon l'environnement et le mode de vie des espèces, le système olfactif doit détecter des odeurs très diverses ; en effet, un moustique qui recherche du sang humain pour se nourrir doit détecter des odeurs bien différentes d'une abeille qui recherche des fleurs. Dans ma thèse, j'ai essayé de comprendre comment les systèmes olfactifs d'une espèce évoluent pour s'adapter aux exigences induites par son environnement. Un très bon modèle pour étudier cela est la drosophile dont les différentes espèces se nichent dans des habitats très divers. Pour ce faire, j'ai étudié les récepteurs olfactifs de différentes espèces de la drosophile. Ces récepteurs sont des protéines qui se lient à des odeurs spécifiques. Lorsqu'ils se lient, ils activent un neurone qui envoie un signal électrique au cerveau. Ce signal est ensuite traité par ce dernier qui indique à la mouche si l'odeur est attractive ou répulsive. J'ai identifié les récepteurs olfactifs de plusieurs espèces de drosophile et étudié s'il y avait des différences entre elles. La plupart des récepteurs sont similaires entre les espèces, cependant dans l'une d'entre elles, certains récepteurs sont différents. Ce fait est particulièrement intéressant car cette espèce de drosophile se nourrit de fruits que les autres espèces n'apprécient pas. Comme nous ne savons pas quels récepteurs se lient à quelles odeurs, j'ai testé un grand nombre de composants odorants. Ceci m'a permis de constater que, effectivement, certains changements produits dans ces récepteurs expliquent pourquoi cette espèce aime particulièrement ces fruits. En outre, mes résultats contribuent à mieux comprendre les changements génétiques qui sont impliqués dans l'évolution du système olfactif.

AssociationViewer: a scalable and integrated software tool for visualization of large-scale variation data in genomic context.

SUMMARY: We present a tool designed for visualization of large-scale genetic and genomic data exemplified by results from genome-wide association studies. This software provides an integrated framework to facilitate the interpretation of SNP association studies in genomic context. Gene annotations can be retrieved from Ensembl, linkage disequilibrium data downloaded from HapMap and custom data imported in BED or WIG format. AssociationViewer integrates functionalities that enable the aggregation or intersection of data tracks. It implements an efficient cache system and allows the display of several, very large-scale genomic datasets. AVAILABILITY: The Java code for AssociationViewer is distributed under the GNU General Public Licence and has been tested on Microsoft Windows XP, MacOSX and GNU/Linux operating systems. It is available from the SourceForge repository. This also includes Java webstart, documentation and example datafiles.