L2L: a simple tool for discovering the hidden significance in microarray expression data

L2L is a database consisting of lists of differentially expressed genes compiled from published mammalian microarray studies, along with an easy-to-use application for mining the database with the user's own microarray data. As illustrated by re-analysis of a recent study of diabetic nephropathy, L2L identifies novel biological patterns in microarray data, providing insights into the underlying nature of biological processes and disease. L2L is available online at the authors' website []

Late Quaternary Marine and Terrestrial Environments, Northwestern Baffin Island, Northwest Territories

Paleoenvironmental data were analyzed from terrestrial, lake, and marine sediments collected near Arctic Bay, Baffin Island, N.W.T. Eighteen new radiocarbon dates provide chronological control, superseding earlier results. Spuriously old dates were obtained from both sandy peats and low-organic lake sediments. The most reliable dates were from marine shells and foraminifera. They indicate that déglaciation was underway by 9000 BP rather than 16,000 BP. Over the period of the record, the local environment was characterized by a high arctic pollen assemblage dominated by grass, sedge, and willow; a middle Holocene warm period is indicated by increased willow, herb, and moss values. Sea-ice conditions were severe enough to inhibit the growth of diatoms until ca. 6300 BP and ice proximal and deglacial conditions prevailed in the fiords until ca. 6000 BP. Diatom productivity increased between 3000 BP and 2500 BP, suggesting warmer surface waters and less sea ice. After 2000 BP diatom accumulation decreased sharply, due to a cooling of climate. The foraminifera indicate a major change in bottom water conditions ca. 4000 BP as the benthic species shift from a calcareous to an arenaceous assemblage.On a procédé à l'analyse des données paléoenvironnementales tirées de sédiments terrestres, marins et lacustres, près de Arctic Bay. Dix-huit nouvelles dates au radiocarbone ont permis d'établir une nouvelle chronologie. Les dates les plus anciennes, et les moins fiables, ont été obtenus dans des tourbes sableuses et des sédiments lacustres à basse teneur organique. Les dates les plus sûres proviennent de coquillages marins et des foraminifères. Elles indiquent que la déglaciation était en cours dès 9000 BP plutôt qu'à 16 000 BP. Pendant la période relevée, l'environnement dans le haut Arctique était caractérisé au niveau local par un assemblage pollinique dominé par l'herbe, le carex et le saule; à l'Holocène moyen, les valeurs croissantes du saule, de l'herbe et de la mousse reflètent une période chaude. La densité de la glace marine était assez forte pour empêcher la croissance des diatomées jusqu'à 6300 BP; la déglaciation s'est poursuivie jusque vers 6000 BP dans les fjords. La reproduction des diatomées a augmenté entre 3000 et 2500 BP en raison de températures de surface plus chaudes et une diminution des glaces marines. Après 2000 BP, l'accumulation des diatomées a décru abruptement en raison d'un refroidissement climatique. Les foraminifères démontrent un changement important survenu dans l'état des eaux profondes vers 4000 BP puisqu'il y a eu remplacement des espèces benthoniques à test calcaire par des espèces à test agglutiné.Man hat Palâoumweltdaten von Erd-, See- und Meeres-Sedimenten analysiert, die man in der Nâhe der Arctic Bay, lnsel Baffin, Nordwest-Territorien gesammelt hat. Achtzehn neue Radiocarbondaten liefern eine chronologische Kontrolle und ersetzen so fruhere Resultate. Faische alte Daten hat man sowohi aus sandigem Ton1 wie auch aus Seesedimenten mit niedrigem organischem Gehalt gewonnen. Die zuver-làssigsten Daten stammen von Meeres-muscheln und Foraminiferen. Sie zeigen, dass die Enteisung urn 9000 v.u.Z. und nicht um 16,000 v.u.Z. im Gange war. Liber den Zeitraum des Belegs charakterisierte sich die lokale Umwelt durch eine Pollen-Zusammensetzung der hohen Arktis, die von Gras, Schilfgras und Weide beherrscht war; auf eine warme Période wâhrend des mittleren Holozàns weisen zunehmende Weiden-, Gras- und Mooswerte. Die Meereseisbedingungen waren streng genug, um das Wachstum von Diatomeen bis etwa 6300 v.u.Z. zu verhindern und Proximaleis und Enteisungsbedingungen herrschten in den Fjords bis etwa 6000 v.u.Z. vor. Die Reproduktion von Diatomeen nahm zwischen 3000 v.u.Z. und 2500 v.u.Z. zu, was auf wàrmeres Oberflàchenwasser und weniger Meereseis schliessen làsst. Nach 2000 v.u.Z. nahm die Diatomeen-Akkumulation wegen einer Klimaabkuhlung plôtzlich ab. Die Foraminiferen zeigen einen betràchtlichen Wechsel der Bedingungen im tiefen Wasser um etwa 4000 v.u.Z., wenn die benthonischen Spezies von einer kalkartigen zu einer sandigen Zusammensetzung ubergehen

Beliefs around luck : confirming the empirical conceptualization of beliefs around luck and the development of the Darke and Freedman beliefs around luck scale

The current study developed a multi-dimensional measure of beliefs around luck. Two studies introduced the Darke and Freedman beliefs around luck scale where the scale showed a consistent 4 component model (beliefs in luck, rejection of luck, being lucky, and being unlucky) across two samples (n = 250; n = 145). The scales also show adequate reliability statistics and validity by ways of comparison with other measures of beliefs around luck, peer and family ratings and expected associations with measures of personality, individual difference and well-being variables

Probing the IGM-Galaxy Connection Toward PKS0405-123 II : A Cross-Correlation Study of Lya Absorbers and Galaxies at z<0.5

We present a pilot study of the clustering properties of Lya absorbers with respect to known galaxies based on 112 Lya absorbers and 482 galaxies identified at z<0.5 along the sightline toward PKS0405-123. The principal goal is to determine the origin of Lya absorbers based on their cross-correlation amplitude with known galaxies and investigate a possible N(HI) dependence of the cross-correlation function. The main results of our study are as follows. (1) The cross-correlation function xi_{ga} measured using only emission-line dominated galaxies and Lya absorbers of log N(HI) >= 14 shows a comparable strength to the galaxy auto-correlation function xi_{gg} on co-moving, projection distance scales < 1 h^{-1} Mpc, while there remains a lack of cross-correlation signal when using only absorption-line dominated galaxies. This signifies a morphology-dependent xi_{ga} and indicates that strong absorbers of log N(HI) >= 14 and emission-line galaxies reside in the same halo population. (2) A maximum-likelihood analysis shows that Lya absorbers of log N(HI) < 13.6 are consistent with being more randomly distributed with respect to known galaxies. Finally, (3) we find based on this single sightline that the amplitude of xi_{ga} does not depend sensitively on N(HI) for strong absorbers of log N(HI) >= 13.6.Comment: 5 pages, including 2 figures; to appear in ApJ Letters, the 2005 August 10 issu

On the cost of electrodialysis for the desalination of high salinity feeds

We propose the use of electrodialysis to desalinate produced waters from shale formations in order to facilitate water reuse in subsequent hydraulic fracturing processes. We focus on establishing the energy and equipment size required for the desalination of feed waters containing total dissolved solids of up to 192,000 ppm, and we do this by experimentally replicating the performance of a 10-stage electrodialysis system. We find that energy requirements are similar to current vapour compression desalination processes for feedwaters ranging between roughly 40,000-90,000 ppm TDS, but we project water costs to potentially be lower. We also find that the cost per unit salt removed is significantly lower when removed from a high salinity stream as opposed to a low salinity stream, pointing towards the potential of ED to operate as a partial desalination process for high salinity waters. We then develop a numerical model for the system, validate it against experimental results and use this model to minimise salt removal costs by optimising the stack voltage. We find that the higher the salinity of the water from which salt is removed the smaller should be the ratio of the electrical current to its limiting value. We conclude, on the basis of energy and equipment costs, that electrodialysis processes are potentially feasible for the desalination of high salinity waters but require further investigation of robustness to fouling under field conditions.Massachusetts Institute of Technology. Office of the Dean for Graduate Education (Hugh Hampton Young Memorial Fellowship)MIT Energy Initiativ

Genetic influences on externalizing psychopathology overlap with cognitive functioning and show developmental variation

Background: Questions remain regarding whether genetic influences on early life psychopathology overlap with cognition and show developmental variation. Methods: Using data from 9,421 individuals aged 8-21 from the Philadelphia Neurodevelopmental Cohort, factors of psychopathology were generated using a bifactor model of item-level data from a psychiatric interview. Five orthogonal factors were generated: anxious-misery (mood and anxiety), externalizing (attention deficit hyperactivity and conduct disorder), fear (phobias), psychosis-spectrum, and a general factor. Genetic analyses were conducted on a subsample of 4,662 individuals of European American ancestry. A genetic relatedness matrix was used to estimate heritability of these factors, and genetic correlations with executive function, episodic memory, complex reasoning, social cognition, motor speed, and general cognitive ability. Gene × Age analyses determined whether genetic influences on these factors show developmental variation. Results: Externalizing was heritable (h2 = 0.46, p = 1 × 10-6), but not anxious-misery (h2 = 0.09, p = 0.183), fear (h2 = 0.04, p = 0.337), psychosis-spectrum (h2 = 0.00, p = 0.494), or general psychopathology (h2 = 0.21, p = 0.040). Externalizing showed genetic overlap with face memory (ρg = -0.412, p = 0.004), verbal reasoning (ρg = -0.485, p = 0.001), spatial reasoning (ρg = -0.426, p = 0.010), motor speed (ρg = 0.659, p = 1x10-4), verbal knowledge (ρg = -0.314, p = 0.002), and general cognitive ability (g)(ρg = -0.394, p = 0.002). Gene × Age analyses revealed decreasing genetic variance (γg = -0.146, p = 0.004) and increasing environmental variance (γe = 0.059, p = 0.009) on externalizing. Conclusions: Cognitive impairment may be a useful endophenotype of externalizing psychopathology and, therefore, help elucidate its pathophysiological underpinnings. Decreasing genetic variance suggests that gene discovery efforts may be more fruitful in children than adolescents or young adults