Physiological studies on the sex-linked dwarfism of the fowl: a review on the search for the gene's primary effect

International audienc

The effect of natural and anthropogenic nutrient and sediment loads on coral oxidative stress on runoff-exposed reefs

Recently, corals on the Great Barrier (GBR) have suffered mass bleaching. The link between ocean warming and coral bleaching is understood to be due to temperature-dependence of complex physiological processes in the coral host and algal symbiont. Here we use a coupled catchment-hydrodynamic-biogeochemical model, with detailed zooxanthellae photophysiology including photoadaptation, photoacclimation and reactive oxygen build-up, to investigate whether natural and anthropogenic catchment loads impact on coral bleaching on the GBR. For the wet season of 2017, simulations show the cross-shelf water quality gradient, driven by both natural and anthropogenic loads, generated a contrasting zooxanthellae physiological state on inshore versus mid-shelf reefs. The relatively small catchment flows and loads delivered during 2017, however, generated small river plumes with limited impact on water quality. Simulations show the removal of the anthropogenic fraction of the catchment loads delivered in 2017 would have had a negligible impact on bleaching rates

Efficient two-step access to azafluorenones and related compounds

International audienceCrystals of a lithiocuprate prepared from copper(I) chloride and lithium 2,2,6,6-tetramethylpiperidide (2 equiv) were isolated and analyzed by X-ray diffraction as (TMP)2Cu(Cl)Li2*THF. The observation of this species is consistent with its having a role in deprotocupration-aroylation. Phenyl pyridyl ketones, phenyl quinolyl ketones, and phenyl thienyl ketones were prepared in tetrahydrofuran using the lithiocuprate and aroyl chorides as electrophiles. Diaryl ketones bearing a chloro group at the 2 position (of a pyridyl or phenyl group) thus synthesized were next converted through palladium-catalyzed ring closure to polycycles of the 5H-indeno[1,2-b]pyridin-5-one, 11H-indeno[1,2-b]quinolin-11-one, 9H-indeno[2,1-c]pyridin-9-one, and 8H-indeno[2,1-b]thiophen-8-one families

Judgment Aggregation with Abstentions under Voters' Hierarchy

International audienceSimilar to Arrow’s impossibility theorem for preference aggregation, judgment aggregation has also an intrinsic impossibility for generating consistent group judgment from individual judgments. Removing some of the pre-assumed conditions would mitigate the problem but may still lead to too restrictive solutions. It was proved that if completeness is removed but other plausible conditions are kept, the only possible aggregation functions are oligarchic, which means that the group judgment is purely determined by a certain subset of participating judges. Instead of further challenging the other conditions, this paper investigates how the judgment from each individual judge affects the group judgment in an oligarchic environment. We explore a set of intuitively demanded conditions under abstentions and design a feasible judgment aggregation rule based on the agents’ hierarchy. We show this proposed aggregation rule satisfies the desirable conditions. More importantly, this rule is oligarchic with respect to a subset of agenda instead of the whole agenda due to its literal-based characteristics

A pedagogic appraisal of the Priority Heuristic

We have explored how science and mathematics teachers made decisions when confronted with a dilemma in which a fictitious young woman, Deborah, may choose to have an operation that might address a painful spinal condition. We sought to explore the extent to which psychological heuristic models, in particular the Priority Heuristic, might successfully describe the decision-making process of these teachers and how an analysis of the role of personal and emotional factors in shaping the decision-making process might inform pedagogical design. A novel aspect of this study is that the setting in which the decision-making process is examined contrasts sharply with those used in psychological experiments. We found that to some extent, even in this contrasting setting, the Priority Heuristic could describe these teachers' decision-making. Further analysis of the transcripts yielded some insights into limitations on scope as well the richness and complexity in how personal factors were brought to bear. We see these limitations as design opportunities for educational intervention

Spatial and temporal variability of the dimethylsulfide to chlorophyll ratio in the surface ocean: an assessment based on phytoplankton group dominance determined from space

Dimethylsulfoniopropionate (DMSP) is produced in surface seawater by phytoplankton. Phytoplankton culture experiments have shown that nanoeucaryotes (NANO) display much higher mean DMSP-to-Carbon or DMSP-to-Chlorophyll (Chl) ratios than Prochlorococcus (PRO), Synechococcus (SYN) or diatoms (DIAT). Moreover, the DMSP-lyase activity of algae which cleaves DMSP into dimethylsulfide (DMS) is even more group specific than DMSP itself. Ship-based observations have shown at limited spatial scales, that sea surface DMS-to-Chl ratios (DMS:Chl) are dependent on the composition of phytoplankton groups. Here we use satellite remote sensing of Chl (from SeaWiFS) and of Phytoplankton Group Dominance (PGD from PHYSAT) with ship-based sea surface DMS concentrations (8 cruises in total) to assess this dependence on an unprecedented spatial scale. PHYSAT provides PGD (either NANO, PRO, SYN, DIAT, Phaeocystis (PHAEO) or coccolithophores (COC)) in each satellite pixel (1/4° horizontal resolution). While there are identification errors in the PHYSAT method, it is important to note that these errors are lowest for NANO PGD which we typify by high DMSP:Chl. In summer, in the Indian sector of the Southern Ocean, we find that mean DMS:Chl associated with NANO + PHAEO and PRO + SYN + DIAT are 13.6±8.4 mmol g−1 (n=34) and 7.3±4.8 mmol g−1 (n=24), respectively. That is a statistically significant difference (P<0.001) that is consistent with NANO and PHAEO being relatively high DMSP producers. However, in the western North Atlantic between 40° N and 60° N, we find no significant difference between the same PGD. This is most likely because coccolithophores account for the non-dominant part of the summer phytoplankton assemblages. Meridional distributions at 22° W in the Atlantic, and 95° W and 110° W in the Pacific, both show a marked drop in DMS:Chl near the equator, down to few mmol g−1, yet the basins exhibit different PGD (NANO in the Atlantic, PRO and SYN in the Pacific). In tropical and subtropical Atlantic and Pacific waters away from the equatorial and coastal upwelling, mean DMS:Chl associated with high and low DMSP producers are statistically significantly different, but the difference is opposite of that expected from culture experiments. Hence, in a majority of cases PGD is not of primary importance in controlling DMS:Chl variations. We therefore conclude that water-leaving radiance spectra obtained simultaneously from ocean color sensor measurements of Chl concentrations and dominant phytoplankton groups can not be used to predict global fields of DMS

N-aryl pyrazoles: DFT calculations of CH acidity and deprotonative metallation using a combination of lithium and zinc amides.

International audienceA series of N-aryl and N-heteroaryl pyrazoles have been deproto-metallated using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination. Mono-, di-, and tri-iodides have been obtained after subsequent trapping with iodine, depending on the substrate and on the quantity of base used. The results have been discussed in the light of the CH acidities of the substrates, determined both in the gas phase and in THF solution using the DFT B3LYP method