Missing Elements and Missing Premises: A Combinatorial Argument for the Ontological Reduction of Chemistry

Does chemistry reduce to physics? If this means Can we derive the laws of chemistry from the laws of physics?', recent discussions suggest that the answer is no'. But sup posing that kind of reduction-- epistemological reduction'--to be impossible, the thesis of ontological reduction may still be true: that chemical properties are determined by more fundamental properties. However, even this thesis is threatened by some objections to the physicalist programme in the philosophy of mind, objections that generalize to the chemical case. Two objections are discussed: that physicalism is vacuous, and that nothing grounds the asymmetry of dependence which reductionism requires. Although it might seem rather surprising that the philosophy of chemistry is affected by shock waves from debates in the philosophy of mind, these objections show that there is an argumentative gap between, on the one hand, the theoretical connection linking chemical properties with properties at the sub-atomic level, and, on the other, the philosophical thesis of ontological reduction. The aim of this paper is to identify the missing premises (among them a theory of physical possibility) that would bridge this gap. Introduction: missing elements and the mystery of discreteness The refutation of physicalism A combinatorial theory of physical possibilia Combinatorialism and the Bohr model Objections The missing premises and a disanalogy with min

Timber permeability : significance for joinery decay

Imperial Users onl

Playing the God game: the perils of religious fictionalism

To what extend can someone who treat religious discourse as fictional discourse live a religious life, that is, one that is informed by that discourse? To what extent can they be integrated into a religious community in which the realist approach is dominant, or at least significantly represented? This paper explores both the possibilities and limitations, of religious fictionalism, and compares it with other non-realist approaches. Finally, a certain kind of agnostic position is presented, one which has something in common with fictionalism, and it is suggested that this latter position may offer the best way of combining religious engagement with a retreat from traditional realism

Biochemical characterisation of LigN, an NAD(+)-dependent DNA ligase from the halophilic euryarchaeon Haloferax volcanii that displays maximal in vitro activity at high salt concentrations

BACKGROUND: DNA ligases are required for DNA strand joining in all forms of cellular life. NAD(+)-dependent DNA ligases are found primarily in eubacteria but also in some eukaryotic viruses, bacteriophage and archaea. Among the archaeal NAD(+)-dependent DNA ligases is the LigN enzyme of the halophilic euryarchaeon Haloferax volcanii, the gene for which was apparently acquired by Hfx.volcanii through lateral gene transfer (LGT) from a halophilic eubacterium. Genetic studies show that the LGT-acquired LigN enzyme shares an essential function with the native Hfx.volcanii ATP-dependent DNA ligase protein LigA. RESULTS: To characterise the enzymatic properties of the LigN protein, wild-type and three mutant forms of the LigN protein were separately expressed in recombinant form in E.coli and purified to apparent homogeneity by immobilised metal ion affinity chromatography (IMAC). Non-isotopic DNA ligase activity assays using λ DNA restriction fragments with 12 bp cos cohesive ends were used to show that LigN activity was dependent on addition of divalent cations and salt. No activity was detected in the absence of KCl, whereas maximum activity could be detected at 3.2 M KCl, close to the intracellular KCl concentration of Hfx.volcanii cells. CONCLUSION: LigN is unique amongst characterised DNA ligase enzymes in displaying maximal DNA strand joining activity at high (> 3 M) salt levels. As such the LigN enzyme has potential both as a novel tool for biotechnology and as a model enzyme for studying the adaptation of proteins to high intracellular salt levels

Does diversity matter?:behavioural differences between piglets given diverse or similar forms of enrichment pre-Weaning

This study investigated the behavioural effects of providing different enrichment materials to suckling piglets from 7 days-old until weaning. One object was attached to the pen wall (WALL), and the other was suspended in the middle of the pen (MID). Control group had the hessian fabric in both locations, and the two diverse groups had hessian and bamboo stick in alternate locations (i.e., BMID-HWALL and HMID-BWALL). Piglets behaviour was recorded on D0 (object introduction), D1, D5, D8, D12, and D14; at weaning and 1, 3, 5 and 15 days after. Groups did not differ in approaching or interacting with objects on D0. MID objects attracted more attention than WALL objects (p < 0.01). Piglets interacted more with hessian than bamboo (p < 0.001). They performed more oral manipulation and shaking with hessian (p < 0.001), but more pushing of bamboo (p < 0.001). Interactions with objects increased with time (p < 0.001), especially with hessian (p < 0.01), while interest in bamboo remained unchanged. Control piglets performed more biting than piglets with diverse enrichment (pooled data), both pre- and post-weaning (p < 0.05). Therefore, providing different types of enrichment material can reduce biting behaviour pre- and post-weaning. Hessian was favoured, possibly because this was easier to bite and shake, which were the behaviours most often observed.Department of Agriculture, Food and the Marine, Irelan

Extraction of soluble proteins by bead milling from Tetraselmis chui in two different physiological states

Tetraselmis is an interesting microalga for food products because of its high protein content and surface productivity as well as the possibility to scale up the culture easily. However, this specie is yet understudied compared to other algae such as Chlorella. Different batches of Tetraselmis chui were received from the same supplier, with different morphological properties, probably associated with a difference in physiological state: one batch contained circular and dividing cells and the other flagellated cells. The batches were characterized biochemically in terms of protein, carbohydrate and ash content and the rupturability was tested to characterize their behavior to cell disruption. One batch was found way more fragile than the other. The bead milling of the two batches showed also striking differences in terms of cell disruption kinetic, as well as dry matter repartition after centrifugation and protein recovery yields within the supernatant. Nearly no differences in protein yield were observed after bead milling in comparison to freeze-thawing for the resistant batch, with a final yield of 11 % of the initial proteins. However, a clear protein release was observed for the fragile batch along the milling residence time, with a final protein yield of 32 %. The protein released were characterized by SDS PAGE and zymography and differences were observed, confirming the difference in metabolism. Several physicochemical modifications were applied to the cell lysate to increase the yields using pH, temperature and dilution. This latest modification was the most promising. The results underlined that a difference in physiological state of Tetraselmis chui had a significant impact on the following biorefinery, affecting directly the cell disruption and the protein recovery yields. The valorization of the whole microalgae thus necessitates the finest coupling between upstream and downstream