Biomarker distributions in surface sediments from the Central Arctic Ocean and adjacent marginal seas

Records of the spatial and temporal variability of Arctic Ocean sea ice are of significance for understanding the causes of the dramatic decrease in Arctic sea-ice cover of recent years. In this context, the newly developed sea-ice proxy IP25, a mono-unsaturated highly branched isoprenoid alkene with 25 carbon atoms biosynthesized specifically by sea-ice associated diatoms and only found in Arctic and sub-Arctic marine sediments, has been used to reconstruct the recent spatial sea-ice distribution. The phytoplankton biomarkers 24S-brassicasterol and dinosterol were determined alongside IP25 to distinguish ice-free or permanent ice conditions, and to estimate the sea-ice conditions semi-quantitatively by means of the phytoplankton-IP25 index (PIP25). Within our study, for the first time a comprehensive data set of these biomarkers was produced using fresh and deep-frozen surface sediment samples from the Central Arctic Ocean proper (>80°N latitude) characterised by a permanent ice cover today and recently obtained surface sediment samples from the Chukchi Plateau/Basin partly covered by perennial sea ice. In addition, published and new data from other Arctic and sub-Arctic regions were added to generate overview distribution maps of IP25 and phytoplankton biomarkers across major parts of the modern Arctic Ocean. These comprehensive biomarker data indicate perennial sea-ice cover in the Central Arctic, ice-free conditions in the Barents Sea and variable sea-ice situations in other marginal seas. The low but more than zero values of biomarkers in the Central Arctic supported the low in-situ productivity there. The PIP25 index values reflect modern sea-ice conditions better than IP25 alone and show a positive correlation with spring/summer sea ice. When calculating and interpreting PIP25 index as a (semi-quantitative) proxy for reconstructions of present and past Arctic sea-ice conditions from different Arctic/sub-Arctic areas, information of the source of phytoplankton biomarkers and the possible presence of allochthonous biomarkers is needed, and the records of the individual biomarkers always should be considered as well.

(Table 1) Geographical location and nutrient composition of saline lake sediments (SLS) and nearby adjacent biological soil crusts (BSC) identified as potential dust sources

While microbial communities of aerosols have been examined, little is known about their sources. Nutrient composition and microbial communities of potential dust sources, saline lake sediments (SLS) and adjacent biological soil crusts (BSC), from Southern Australia were determined and compared with a previously analyzed dust sample. Multivariate analyses of fingerprinting profiles indicated that the bacterial communities of SLS and BSC were different, and these differences were mainly explained by salinity. Nutrient concentrations varied among the sites but could not explain the differences in microbial diversity patterns. Comparison of microbial communities with dust samples showed that deflation selects against filamentous cyanobacteria, such as the Nostocales group. This could be attributed to the firm attachment of cyanobacterial filaments to soil particles and/or because deflation occurs mainly in disturbed BSC, where cyanobacterial diversity is often low. Other bacterial groups, such as Actinobacteria and the spore-forming Firmicutes, were found in both dust and its sources. While Firmicutes-related sequences were mostly detected in the SLS bacterial communities (10% of total sequences), the actinobacterial sequences were retrieved from both (11-13%). In conclusion, the potential dust sources examined here show highly diverse bacterial communities and contain nutrients that can be transported with aerosols. The obtained fingerprinting and sequencing data may enable back tracking of dust plumes and their microorganisms.

Concentrations of organic carbon and organic matter isotopic compositions of sapropels and adjacent marls from ODP Hole 161-974B in the Tyrrhenian Basin (Table 1)

Multiple layers of sapropels occur widely in the sedimentary record of the Mediterranean Sea and record repetitions of paleoclimatic conditions that favored increased production and preservation of marine organic matter. A combination of hydrogen and carbon isotope analyses of Pleistocene sapropels from the Tyrrhenian Sea reveals new aspects of the factors leading to their deposition. Organic matter dD values that are significantly more negative in sapropels than in adjacent marls indicate a combination of dilution of surface waters by meteoric waters and increased burial of lipid-rich organic matter during periods of sapropel deposition. Organic d13C values in sapropels that are less negative than those in marls suggest periods of markedly elevated marine biological production. The opposite but concordant excursions of these two isotopic parameters imply that the sapropel layers formed from increased export of marine organic matter from the photic zone to the sea floor during periods of greater fluvial delivery of continental nutrients to the Mediterranean Sea. Furthermore, the isotopic evidence indicates that periods of wetter climate were widespread in southern Europe at the same times as in northern Africa.

(Table 1) AMS-14C ages determined in pairs of spreiten and directly adjacent host sediment of cores M39029-4 and M29039-8

he downward transport of surface sediment deep into the sediment column by the Zoophycos-producing animal leads not only to large age differences between the Zoophycos structure and surrounding host sediment but also to large differences in age between different foraminifer species found inside the trace fossil. In the late Quaternary material from the southwestern Portuguese continental slope examined in this study, age differences of up to 2590 years were observed between the planktic foraminifer species Globigerinoides ruber and Globigerina bulloides. These differences are caused by the mixing of surface and host material with different abundances of the two species. If there are differences in the abundance of the two species at the surface and/or in the host sediment, plenty of relatively young foraminifers may be mixed with few relatively old ones, or vice versa. The age differences between species caused by the combination of deep-reaching bioturbation by the Zoophycos producer and abundance variations may be considerably larger than the age differences caused by the homogenizing bioturbation in the mixed layer.

Partner selection for reverse logistics centres in green supply chains: a fuzzy artificial immune optimization approach

The design of reverse logistics networks has now emerged as a major issue for manufacturers, not only in developed countries where legislation and societal pressures are strong, but also in developing countries where the adoption of reverse logistics practices may offer a competitive advantage. This paper presents a new model for partner selection for reverse logistic centres in green supply chains. The model offers three advantages. Firstly, it enables economic, environment, and social factors to be considered simultaneously. Secondly, by integrating fuzzy set theory and artificial immune optimization technology, it enables both quantitative and qualitative criteria to be considered simultaneously throughout the whole decision-making process. Thirdly, it extends the flat criteria structure for partner selection evaluation for reverse logistics centres to the more suitable hierarchy structure. The applicability of the model is demonstrated by means of an empirical application based on data from a Chinese electronic equipment and instruments manufacturing company.

Formation of helical ion chains

We study the nonequilibrium dynamics of the linear to zigzag structural phase transition exhibited by an ion chain confined in a trap with periodic boundary conditions. The transition is driven by reducing the transverse confinement at a finite quench rate, which can be accurately controlled. This results in the formation of zigzag domains oriented along different transverse planes. The twists between different domains can be stabilized by the topology of the trap and under laser cooling the system has a chance to relax to a helical chain with nonzero winding number. Molecular dynamics simulations are used to obtain a large sample of possible trajectories for different quench rates. The scaling of the average winding number with different quench rates is compared to the prediction of the Kibble-Zurek theory, and a good quantitative agreement is found.

Non-Gaussian distribution of collective operators in quantum spin chains

We numerically analyse the behavior of the full distribution of collective observables in quantum spin chains. While most of previous studies of quantum critical phenomena are limited to the first moments, here we demonstrate how quantum fluctuations at criticality lead to highly non-Gaussian distributions. Interestingly, we show that the distributions for different system sizes collapse on thesame curve after scaling for a wide range of transitions: first and second order quantum transitions and transitions of the Berezinskii–Kosterlitz–Thouless type. We propose and analyse the feasibility of an experimental reconstruction of the distribution using light–matter interfaces for atoms in optical lattices or in optical resonators.

Structural characterization of interaction of K11 and K63 mixed-linkage polyubiquitin chains with the tUIMs of epsin1

Ubiquitylation or covalent attachment of ubiquitin (Ub) to a variety of substrate proteins in cells is a versatile post-translational modification involved in the regulation of numerous cellular processes. The distinct messages that polyubiquitylation encodes are attributed to the multitude of conformations possible through attachment of ubiquitin monomers within a polyubiquitin chain via a specific lysine residue. Thus the hypothesis is that linkage defines polyubiquitin conformation which in turn determines specific recognition by cellular receptors. Ubiquitylation of membrane surface receptor proteins plays a very important role in regulating receptor-mediated endocytosis as well as endosomal sorting for lysosomal degradation. Epsin1 is an endocytic adaptor protein with three tandem UIMs (Ubiquitin Interacting Motifs) which are responsible for the highly specific interaction between epsin and ubiquitylated receptors. Epsin1 is also an oncogenic protein and its expression is upregulated in some types of cancer. Recently it has been shown that novel K11 and K63 mixed-linkage polyubiquitin chains serve as internalization signal for MHC I (Major Histocompatibility Complex I) molecule through their association with the tUIMs of epsin1. However the molecular mode of action and structural details of the interaction between polyubiquitin chains on receptors and tUIMs of epsin1 is yet to be determined. This information is crucial for the development of anticancer therapeutics targeting epsin1. The molecular basis for the linkage-specific recognition of K11 and K63 mixed-linkage polyubiquitin chains by the tandem UIMs of the endocytic adaptor protein epsin1 is investigated using a combination of NMR methods.

Investigations into the mechanism of orotidine 5'-monophosphate decarboxylase: Sources of substrate destabilization and transition state stabilization

Orotidine 5′-monophosphate decarboxylase (OMPDC) achieves a rarely paralleled rate acceleration, yet the catalytic basis prompting this enhancement have yet to be fully elucidated. To accomplish decarboxylation, OMPDC must overcome the high energy barrier due to the localized anionic charge of the intermediate. Mechanistic studies employing enzyme mutagenesis and product or intermediate analogues were used to investigate possible transition state stabilization by a carbene resonance structure. Viability of the carbene structure depends upon a key hydrogen bond between O4 of the substrate and the amide backbone of a conserved serine or threonine. Substitution of the conserved residue with Pro resulted in a kcat/KM of 1 M-1s-1; deletion of the FUMP O4 resulted in a product analogue that does not undergo H6 exchange or inhibit decarboxylation. Hence, indirect evidence reveals the O4-backbone interaction plays an important role for binding and catalysis. OMPDC likely has honed multiple mechanisms to attain its remarkable catalysis. The successful crystallizations of OMPDC a decade ago sparked hypotheses that structure and sequence conserved residues induced productive strain on the substrate-enzyme complex. Here, we demonstrate a new source of stress: a hydrophobic pocket adjacent to the OMP carboxylate that exhibits kinetic parameters characteristic of substrate destabilization. Substitution of these residues with hydrophilic side-chains, by providing hydrogen-bonding partners, decreased kcat by 10 to 10^4–fold. The same substitutions display very little change in the rate of product H6 exchange, supporting that this hydrophobic pocket affects the substrate-enzyme complex before the transition state. We also provide evidence that hydrophilic residues can insert water molecules into the pocket with detrimental effects to catalysis.

Two novel COLVI long chains in zebrafish that are essential for muscle development

Collagen VI (COLVI), a protein ubiquitously expressed in connective tissues, is crucial for structural integrity, cellular adhesion, migration and survival. Six different genes are recognized in mammalians, encoding six COLVI-chains that assemble as two ‘short’ (α1, α2) and one ‘long’ chain (theoretically any one of α3–6). In humans, defects in the most widely expressed heterotrimer (α123), due to mutations in the COL6A1-3 genes, cause a heterogeneous group of neuromuscular disorders, collectively termed COLVI-related muscle disorders. Little is known about the function(s) of the recently described α4-6 chains and no mutations have been detected yet. In this study, we characterized two novel COLVI long chains in zebrafish that are most homologous to the mammalian α4 chain; therefore, we named the corresponding genes col6a4a and col6a4b. These orthologues represent ancestors of the mammalian Col6a4-6 genes. By in situ hybridization and RT-qPCR, we unveiled a distinctive expression kinetics for col6a4b, compared with the other col6a genes. Using morpholino antisense oligonucleotides targeting col6a4a, col6a4b and col6a2, we modelled partial and complete COLVI deficiency, respectively. All morphant embryos presented altered muscle structure and impaired motility. While apoptosis was not drastically increased, autophagy induction was defective in all morphants. Furthermore, motoneuron axon growth was abnormal in these morphants. Importantly, some phenotypical differences emerged between col6a4a and col6a4b morphants, suggesting only partial functional redundancy. Overall, our results further confirm the importance of COLVI in zebrafish muscle development and may provide important clues for potential human phenotypes associated with deficiency of the recently described COLVI-chains.

Management accounting and supply chains: actions, concerns, and networks

What does this thesis do? This thesis uses Actor-Network Theory (ANT) to examine how a UK retailer’s organization and strategy, and, in turn, its form of management accounting was shaped by its supply chain. The thesis does this by reporting on four related themes in the form of four inter-connected essays. The first essay undertakes a state-of-the-art review of the literature. It examines how accounting issues within supply chains permeate ‘matters of concern’. In accordance with this idea of ANT, the essay illustrates how issues emerged, controversies developed, and matters evolved through an actor-network of accounting researchers within the supply chain domain. This leads on to the second essay, which exemplifies the nature of the UK’s retailing industry within which the supply chain case organization emerged and developed. The purposes of the essay are twofold: to introduce the contextual ramifications of the case organization; and to illustrate the emergence of a new market logic, which led to the creation of a global supply chain and a new form of management accounting therein. The third essay reports on a qualitative case study. It analyses the dualistic relation between ostensive and performative aspects of supply chain strategy, reveals how accounting numbers act as an obligatory passage point within this dualism, and makes a contribution to the ANT debate around the issue of whether and how a dualism between ostensive and performative aspects exists. The final essay reports on another case analysis of institutionalizing a heterarchical form of management accounting: a distributed form of intelligence that penetrates through lateral accountable relations. The analysis reveals a new form of management accounting characterised by ambiguity; it emphasizes the possibilities of compromises and negotiations, and it thus contributes to knowledge by combining an aspect of ANT with heterarchical tendencies in the world of contemporary organizations. Finally, the thesis concludes that it is the supply chain that organises today’s neoliberal capitalism; and it is management accounting that unites both human and non-human actors within such supply chains, despite that form of management accounting being ambiguous. The thesis comprises the introduction, these four essays, and the conclusion.

[Rapid transit map of Manhattan and adjacent districts of New York City].

Covers Manhattan, South Bronx, and small adjacent parts of Queens, Brooklyn, and Jersey City.

Blackwell's, Ward's and Randall's islands and adjacent shores of East and Harlem rivers from 51st St. New York to Lawrence's Pt.

Scale 1:5,000.

Value chain transformation: Taking stock of WorldFish research on value chains and markets

The goal of WorldFish’s research on markets and value chains is to increase the benefits to resource-poor people from fisheries and aquaculture value chains by researching (1) key barriers to resource-poor men, women and other marginalized groups gaining greater benefits from participation in value chains, including barriers related to the availability, affordability and quality of nutrient-rich fish for resource-poor consumers; (2) interventions to overcome those barriers; and (3) mechanisms that are most effective for scaling up of value chain interventions. This paper aims to promote and document learning across WorldFish’s value chain research efforts in Asia and Africa. It has three main objectives: (1) to take stock of WorldFish’s past and ongoing research on value chains; (2) to draw out commonalities and differences between these projects; and (3) to provide a synthesis of some learning that can guide future work.