Baffin Island Fjord Macrobenthos: Bottom Communities and Environmental Significance

Cluster analysis of the benthos from ten Baffin Island fjords defines six faunal associations. The macrotidal Sunneshine Fiord has a shallow kelp-related Isopod Association. Cambridge Fiord supports a shallow Onuphid Association controlled by gravel from dropstones. A widespread Portlandia Association typified the shallow zones of more recently glaciated fjords where sedimentation rates are high. An Ophiuroid-Anemone Association was defined from current-affected submarine channel environments. A Maldanid Association covered the greatest area in all fjords and passed into an Elasipod Association in the deepest water in Cambridge Fiord. Fjord-head faunas are used to model ecological changes accompanying glacier retreat, from monospecific Portlandia, through mature Portlandia Association to Onuphid Association accompanied by diverse filter feeders and herbivores. Chlamys islandica was found living in Cambridge Fiord, which substantially increases its northern limit.Key words: macrobenthos, Arctic, cluster analysis, bivalve, Quaternary, sedimentMots clés: macrobenthos, Arctique, analyse d’ensemble, bivalve, quaternaire, sédiment

Dimeric FcγR ectodomains detect pathogenic anti-platelet factor 4-heparin antibodies in heparin-induced thromobocytopenia

Background Heparin‐induced thrombocytopenia (HIT) is a major and potentially fatal consequence of antibodies produced against platelet factor 4 (PF4)–heparin complexes following heparin exposure. Not all anti‐PF4–heparin antibodies are pathogenic, so overdiagnosis can occur, with resulting inappropriate use of alternative anticoagulation therapies that have associated risks of bleeding. However, definitive platelet functional assays are not widely available for routine analysis. Objectives To assess the utility of dimeric recombinant soluble FcγRIIa (rsFcγRIIa) ectodomains for detecting HIT antibodies. Patients/Methods Plasma from 27 suspected HIT patients were tested for pathogenic anti‐PF4–heparin antibodies by binding of a novel dimeric FcγRIIa ectodomain probe. Plasmas were also tested by the use of PF4–heparin IgG ELISA, the HemosIL AcuStar HIT IgG‐specific assay, and a serotonin release assay (SRA). Results The dimeric rsFcγRIIa test produced no false positives and excluded four samples that were positive by IgG ELISA. In this small patient cohort, the novel assay correctly assigned 93% of the suspected HIT patients, with two of the HIT patients being scored as false negatives. The improved discrimination of the novel assay over the IgG ELISA, which scored four false positives, supports the mechanistic interpretation that binding of dimeric rsFcγRIIa detects pairs of closely spaced IgG antibodies in PF4–heparin immune complexes. Conclusions This study found the cell‐free, function‐based dimeric rsFcγRIIa assay to be convenient, simple, and potentially predictive of HIT. The assay had improved specificity over the IgG ELISA, and correlated strongly with the AcuStar HIT IgG‐specific assay, warranting further evaluation of its potential to identify HIT in larger patient cohorts

Response to Guttman & Levy's article ‘on the definition and varieties of attitude and wellbeing’

Guttman and Levy have prepared an extravagant critique focused mainly on the 1980 Andrews-McKennell article in this journal. The clearly stated purpose of that article was to report a “series of explorations into the affective and cognitive components of some of the more widely used measures of perceived well-being”. Guttman and Levy ignore this. They proceed on the mistaken impression that we were (or perhaps should have been) embarking upon a definitional exercise to relate the concepts of attitude and wellbeing. Yet the reason we did not cite their article on that topic was precisely because it did not address in a direct or focused way the topic that concerned us. Their critique consists of an entirely irrelevant reanalysis of some attitudinal data by Ostrom, together with a tissue of recondite definitional and methodological issues of little consequence either for the objectives or the conclusions of our research. Their dismissal of our work as ‘scientific retrogression’ rests on an a priori definition of science that fits their own methodological style but excludes that of many other prominent researchers. Their comments reflect an attempt at methodological imperialism. We defend our independence — and that of other investigators — to use promising new methodologies other than the particular approach advocated by Guttman and Levy. (Their denunciation of the new methods of structural equation modeling is not shared even by the authoritative reviewer they themselves quote.) In addition to Guttman and Levy's specific criticisms, our Response addresses general methodological issues such as the status of structural modeling and the testing of structural models. In a concluding section we identify areas that merit further research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43680/1/11205_2004_Article_BF00302509.pd

Noncolliding Squared Bessel Processes

We consider a particle system of the squared Bessel processes with index $\nu > -1$ conditioned never to collide with each other, in which if $-1 < \nu < 0$ the origin is assumed to be reflecting. When the number of particles is finite, we prove for any fixed initial configuration that this noncolliding diffusion process is determinantal in the sense that any multitime correlation function is given by a determinant with a continuous kernel called the correlation kernel. When the number of particles is infinite, we give sufficient conditions for initial configurations so that the system is well defined. There the process with an infinite number of particles is determinantal and the correlation kernel is expressed using an entire function represented by the Weierstrass canonical product, whose zeros on the positive part of the real axis are given by the particle-positions in the initial configuration. From the class of infinite-particle initial configurations satisfying our conditions, we report one example in detail, which is a fixed configuration such that every point of the square of positive zero of the Bessel function $J_{\nu}$ is occupied by one particle. The process starting from this initial configuration shows a relaxation phenomenon converging to the stationary process, which is determinantal with the extended Bessel kernel, in the long-term limit.Comment: v3: LaTeX2e, 26 pages, no figure, corrections made for publication in J. Stat. Phy

Stepped fans and facies-equivalent phyllosilicates in Coprates Catena, Mars

Stepped fan deposits and phyllosilicate mineralogies are relatively common features on Mars but have not previously been found in association with each other. Both of these features are widely accepted to be the result of aqueous processes, but the assumed role and nature of any water varies. In this study we have investigated two stepped fan deposits in Coprates Catena, Mars, which have a genetic link to light-toned material that is rich in Fe–Mg phyllosilicate phases. Although of different sizes and in separate, but adjacent, trough-like depressions, we identify similar features at these stepped fans and phyllosilicates that are indicative of similar formation conditions and processes. Our observations of the overall geomorphology, mineralogy and chronology of these features are consistent with a two stage formation process, whereby deposition in the troughs first occurs into shallow standing water or playas, forming fluvial or alluvial fans that terminate in delta deposits and interfinger with interpreted lacustrine facies, with a later period of deposition under sub-aerial conditions, forming alluvial fan deposits. We suggest that the distinctive stepped appearance of these fans is the result of aeolian erosion, and is not a primary depositional feature. This combined formation framework for stepped fans and phyllosilicates can also explain other similar features on Mars, and adds to the growing evidence of fluvial activity in the equatorial region of Mars during the Hesperian and Amazonian

Ozone induces glucose intolerance and systemic metabolic effects in young and aged brown Norway rats

Air pollutants have been associated with increased diabetes in humans. We hypothesized that ozone would impair glucose homeostasis by altering insulin signaling and/or endoplasmic reticular (ER) stress in young and aged rats. One, 4, 12, and 24 month old Brown Norway (BN) rats were exposed to air or ozone, 0.25 or 1.0 ppm, 6 h/day for 2 days (acute) or 2 d/week for 13 weeks (subchronic). Additionally, 4 month old rats were exposed to air or 1.0 ppm ozone, 6 h/day for 1 or 2 days (time-course). Glucose tolerance tests (GTT) were performed immediately after exposure. Serum and tissue biomarkers were analyzed 18 h after final ozone for acute and subchronic studies, and immediately after each day of exposure in the time-course study. Age-related glucose intolerance and increases in metabolic biomarkers were apparent at baseline. Acute ozone caused hyperglycemia and glucose intolerance in rats of all ages. Ozone-induced glucose intolerance was reduced in rats exposed for 13 weeks. Acute, but not subchronic ozone increased α2-macroglobulin, adiponectin and osteopontin. Time-course analysis indicated glucose intolerance at days 1 and 2 (2> 1), and a recovery 18 h post ozone. Leptin increased day 1 and epinephrine at all times after ozone. Ozone tended to decrease phosphorylated insulin receptor substrate-1 in liver and adipose tissues. ER stress appeared to be the consequence of ozone induced acute metabolic impairment since transcriptional markers of ER stress increased only after 2 days of ozone. In conclusion, acute ozone exposure induces marked systemic metabolic impairments in BN rats of all ages, likely through sympathetic stimulation