Reply to the discussion by Karen Johannesson on “Rare earth element geochemistry of scleractinian coral skeleton during meteoric diagenesis: a sequence through neomorphism of aragonite to calcite” by Webb et al., Sedimentology, 56, 1433-1463

Webb et al. (2009) described a late Pleistocenecoral sample wherein the diagenetic stabilization of original coral aragonite to meteoric calcite was halted more or less mid-way through the process, allowing direct comparison of pre-diagenetic and post-diagenetic microstructure and trace element distributions. Those authors found that the rare earth elements (REEs) were relatively stable during meteoric diagenesis, unlike divalent cations such as Sr,and it was thus concluded that original, in this case marine, REE distributions potentially could be preserved through the meteoric carbonate stabilization process that must have affected many, if not most, ancient limestones. Although this was not the case in the analysed sample, they noted that where such diagenesis took place in laterally transported groundwater, trace elements derived from that groundwater could be incorporated into diagenetic calcite, thus altering the initial REE distribution (Banner et al., 1988). Hence, the paper was concerned with the diagenetic behaviour of REEs in a groundwater-dominated karst system. The comment offered by Johannesson (2011) does not question those research results, but rather, seeks to clarify an interpretation made by Webb et al. (2009) of an earlier paper, Johannesson et al. (2006).

Have we misinterpreted the study of Hoogerheide et al. (1971)?

In 1971, Rempt et al. reported peripheral refraction patterns (skiagrams) along the horizontal visual field in 442 people. Later in the same year, Hoogerheide et al. used skiagrams in combination with medical records to relate skiagrams in emmetropes and hyperopes to progression of myopia in young adults. The two articles have spurred interest in peripheral refraction in the past decade. We challenge the understanding that their articles provide evidence that the peripheral refraction pattern along the horizontal visual field is predictive of whether or not a person develops myopia. First, although it has been generally assumed that the skiagrams were measured before the changes in refraction were monitored, Hoogerheide et al. did not state that this was the case. Second, if the skiagrams were obtained at an initial examination and given the likely rates of recruitment and successful completion of training, the study must have taken place during a period of 10 to 15 years; it is much more likely that Hoogerheide et al. measured the skiagrams in a shorter period. Third, despite there being many more emmetropes and hyperopes in the Rempt et al. article than there are in the Hoogerheide et al. article, the number of people in two types of “at risk” skiagrams is greater in the latter; this is consistent with the central refraction status being reported from an earlier time by Hoogerheide et al. than by Rempt et al. In summary, we believe that the skiagrams reported by Hoogerheide et al. were taken at a later examination, after myopia did or did not occur, and that the refraction data from the initial examination were retrieved from the medical archives. Thus, this work does not provide evidence that peripheral refraction pattern is indicative of the likely development of myopia.

Rôle des microorganismes sur la spéciation du Cu, Zn et Al dans la rhizosphère de sols forestiers

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Comment on "Tropospheric temperature response to stratospheric ozone recovery in the 21st century" by Hu et al. (2011)

Abstract. In a recent paper Hu et al. (2011) suggest that the recovery of stratospheric ozone during the first half of this century will significantly enhance free tropospheric and surface warming caused by the anthropogenic increase of greenhouse gases, with the effects being most pronounced in Northern Hemisphere middle and high latitudes. These surprising results are based on a multi-model analysis of CMIP3 model simulations with and without prescribed stratospheric ozone recovery. Hu et al. suggest that in order to properly quantify the tropospheric and surface temperature response to stratospheric ozone recovery, it is necessary to run coupled atmosphere-ocean climate models with stratospheric ozone chemistry. The results of such an experiment are presented here, using a state-of-the-art chemistry-climate model coupled to a three-dimensional ocean model. In contrast to Hu et al., we find a much smaller Northern Hemisphere tropospheric temperature response to ozone recovery, which is of opposite sign. We suggest that their result is an artifact of the incomplete removal of the large effect of greenhouse gas warming between the two different sets of models.

Vivipary in the cactus family: A reply to Ortega-Baes` et al. evaluation of 25 species from northwestern Argentina

This is a reply to Ortega-Baes` et al. (2010) survey of 25 Argentinean species of cacti evaluated for vivipary. We argue that the sample size and geographic area of the species investigated is insufficient to totally exclude the putative commonness of this condition in the Cactaceae. We indicate possible reasons why they did not find viviparous fruits in their survey. Failure to detect vivipary in cacti of NW Argentina may be correlated with limited taxonomic sampling and geographic region in addition to intrinsic and extrinsic plant factors, including different stages of fruit and seed development and genetic, ecological, and edaphic aspects, which, individually or in concert, control precocious germination. We uphold that viviparity is putatively frequent in this family and list 16 new cases for a total of 53 viviparous cacti, which make up ca. 4% incidence of viviparism in the Cactaceae, a substantially higher percentage than most angiosperm families exhibiting this condition. The Cactaceae ranks fourth in frequency of viviparity after the aquatic families of mangroves and seagrasses. We suggest the re-evaluation of cactus vivipary, primarily as a reproductive adaptation to changing environments and physiological stress with a secondary role as a reproductive strategy with limited offspring dispersal/survival and fitness advantages. (C) 2011 Elsevier Ltd. All rights reserved.

Applying King et al.'s taxonomy to frame the IS discipline's engagement in green IS discourse

This paper considers how the IS discipline can engage with discourse on the institutions and their interventions which influence and regulate green IS innovation. To consider possible responses, we apply King et al.’s (1994) taxonomy, based on Institutional Theory, to frame a research agenda to guide future exploration and debate on the interventions to facilitate green IS innovation. Through the application of the taxonomy, we derive several pertinent questions for the discipline to consider as part of this debate. We conclude that the IS discipline can, and indeed should, play a more prominent role both through traditional responses (e.g., descriptive studies of green IS methodologies, organisational best practice, maturity models, etc.), but also through more active engagement in the form of participation and advocacy in shaping future green policy and regulation.