5,641 research outputs found
Synthesis and coordination chemistry of hybrid polydentate and halide-substituted stibines and bismuthines
No full textHalostibines and halobismuthines EMenX3-n (E = Sb, Bi; X = Cl, Br; n = 1, 2) display both Lewis acidic and Lewis basic characteristics. A series of adducts with neutral N- and O-donor ligands, [EMeX2(L)] (L = 2,2’-bipyridine, 1,10-phenanthroline, tetramethylethylenediamine) and [SbMeX2(L)2] (L = Ph3PO, Me3PO) were isolated and characterised by X-ray crystallography, 1H (and where appropriate 31P{1H}) NMR spectroscopy and microanalysis. Each complex is monomeric, displaying a distorted square pyramidal geometry around E, with two basal cis halides and the Me group apical. Combination of EMe2X with neutral ligands results in rearrangement at E to yield [EMeX2(L)] or [SbMeX2(L)2] once again as the isolable products. Reaction of SbMenBr3-n (n = 1, 2) with transition metal acceptors gives complexes in which the halostibines behave as Lewis bases. Examination of trends in the crystallographic and spectroscopic data of [M(CO)5(SbMenBr3-n)] (M = Cr, W; n = 1-3) from this work and the literature concluded that the halostibines have a significant ?-acceptor ability, which increases with increased halide substitution. Other transition metal complexes with L = SbMe2Br, [CpFe(CO)2(L)][BF4], [CpFe(CO)(L)2]Br (Cp = cyclopentadienyl) and [Mn(CO)6-n(L)n][CF3SO3] (n = 1, 3) were isolated and contain hypervalent, Sb···O, Sb···F or Sb···Br contacts between ions. Reaction of BiMe2Br with transition metal acceptors results in rearrangement at Bi; the only bismuthine complexes isolated contained the BiMe3 ligand.The hybrid distibine S(CH2-2-C6H4SbMe2)2 and its methiodide [S(CH2-2-C6H4SbMe3)2][I]2 were synthesised and the X-ray structure of the latter determined. Systematic investigations into transition metal complexes of this and other hybrid distibine ligands were undertaken. These ligands coordinate in a bidentate bridging mode in the 1:2 complexes [{CpFe(CO)2}2(L)][BF4] (L = O{(CH2)2SbR2}2 (R = Me, Ph), MeN(CH2-2-C6H4SbMe2)2, S(CH2-2-C6H4SbMe2)2) and [{M(CO)5}2(L)] (M = Cr, W; L = O{(CH2)2SbR2}2 (R = Me, Ph)), a bidentate chelating mode in [M(CO)4(L)] (M = Cr, W; L = O{(CH2)2SbMe2}2, MeN(CH2-2-C6H4SbMe2)2) or a tridentate mode in [M(CO)3(S(CH2-2-C6H4SbMe2)2)] (M = Cr, Mo) and [Mn(CO)3(L)] [CF3SO3] (L = MeN(CH2-2-C6H4SbMe2)2, S(CH2-2-C6H4SbMe2)2). In the latter examples the central hetero-atom of the ligand is coordinated to the transition metal centre. In those cases where it is not, hypervalent interactions between this hetero-atom and one or both coordinated Sb atoms are sometimes, but not always, observed. Comparisons have been drawn with the chemistry of the corresponding hybrid dibismuthine ligands. The hybrid tristibine ligand N(CH2-2-C6H4SbMe2)3 was synthesised and preliminary investigations of its coordination chemistry carried out. It acts as a tridentate ligand via the three Sb donors in [Mn(CO)3(L)][CF3SO3] and [Cu4Br4(L)2], with the ligand fixed in a propeller-like conformation. In the latter, a Cu2Br4 core with a short Cu···Cu distance is observed. [Cu(L)] [BF4] was isolated, in which tetradentate coordination of the ligand has been proposed.Transition metal complexes were characterised by 1H and 13C{1H} NMR spectroscopy and microanalysis, and where appropriate infrared and 55Mn or 63Cu NMR spectroscopies and mass spectrometry. The majority of these complexes have also been structurally characterised by single crystal X-ray diffraction
sj-jpg-4-gph-10.1177_2333794X221091799 – Supplemental material for Climate Change Affects Health: Are We Listening?
No full textSupplemental material, sj-jpg-4-gph-10.1177_2333794X221091799 for Climate Change Affects Health: Are We Listening? by Gabriel S. Chain, Benjamin M. Chain and Frances B. Pelliccia in Global Pediatric Health</p
sj-jpg-1-gph-10.1177_2333794X221091799 – Supplemental material for Climate Change Affects Health: Are We Listening?
No full textSupplemental material, sj-jpg-1-gph-10.1177_2333794X221091799 for Climate Change Affects Health: Are We Listening? by Gabriel S. Chain, Benjamin M. Chain and Frances B. Pelliccia in Global Pediatric Health</p
sj-jpg-2-gph-10.1177_2333794X221091799 – Supplemental material for Climate Change Affects Health: Are We Listening?
No full textSupplemental material, sj-jpg-2-gph-10.1177_2333794X221091799 for Climate Change Affects Health: Are We Listening? by Gabriel S. Chain, Benjamin M. Chain and Frances B. Pelliccia in Global Pediatric Health</p
sj-jpg-3-gph-10.1177_2333794X221091799 – Supplemental material for Climate Change Affects Health: Are We Listening?
No full textSupplemental material, sj-jpg-3-gph-10.1177_2333794X221091799 for Climate Change Affects Health: Are We Listening? by Gabriel S. Chain, Benjamin M. Chain and Frances B. Pelliccia in Global Pediatric Health</p
The importance of network goals for strategic chain management
No full textNowadays food products are increasingly produced in supply chain networks that involve numerous firms. Due to their pyramidal-hierarchical structure, such networks possess a focal company that coordinates the network. The managerial task of the focal company is to work out collective strategy that addresses cooperation and coordination problems at the firm, dyadic and network levels. These strategies must take into account that at each level specific goals must be achieved. Though the focal company is a strategy setting unit that sets network goals, other network actors may perceive these goals as firm-level goals of the focal company. Therefore, conflicts may occur in supply chain networks.Supply chain networks, focal company, network goals, Agribusiness,
Bayesian representations using chain event graphs
No full textBayesian networks (BNs) are useful for coding conditional independence statements between a given set of measurement variables.
On the other hand, event trees (ETs) are convenient for representing asymmetric structure and how situations unfold. In this paper
we report the development of a new graphical framework for discrete
probability models called the Chain Event Graph (CEG). The class of
CEG models contains finite BNs as a special case. Unlike the BN, the
CEG is equally appropriate for representing conditional independencies in asymmetric systems and does not need dependent variables to
be specified in advance. As with the BN, it also provides a framework
for learning relevant conditional probabilities and propagation. Furthermore, being a function of an ET, the CEG is a more
exible way of
representing various causal hypotheses than the BN. This new framework is illustrated throughout by a biological regulatory network: the
tryptophan metabolic pathway in the bacterium E. coli
Supply chain management research impact: an evidence based perspective
No full textThe purpose of this paper, using an evidenceî ̧based management theoretical lens, is to examine research impact to provide guidance to supply chain management academics in evidencing and exploiting the outputs, outcomes and impact of their research. Evidenceî ̧based management theory is examined and applied to types of academic research impact. The distinction between academic and nonî ̧academic impact is developed into a supply chain framework of research outputs, transfer, outcomes, impact and national/international benefits. Impact of supply chain management research is explored through a case study in the English National Health Service. Future opportunities and challenges for supply chain management researchers arising from increasing demand for and supply of evidence are discussed. Author academic impact and citations are found to be increasingly important building blocks of evidenceî ̧based evaluations of individual academics, journals, research quality assessments of groups and universities, and global rankings of universities. Supply chain management researchers can compare their impact with other areas of academia. Nonî ̧academic impact of research has been assessed by funders of research projects and has spread to research quality assessments of universities. Bibliometrics provide evidence of author and journal impact that can be used in human resource decisions, research quality assessments and global rankings of universities; this availability enables a debate on appropriate use of academic impact evidence. Supply chain management academics evidencing nonî ̧academic research impact on business, society and economy will enable governments and funders of research to evaluate value for money return on their investment. This perspective of evidenceî ̧based evaluation of research impact and its implications might encourage debate on academic and nonî ̧academic impact and encourage supply chain researchers to consider evidencing impact in their research design and methodology. © 2013, Emerald Group Publishing Limite
Dairy supply chain restructuring and its impact on farmers' revenues in Poland
No full textSupply chain restructuring and its impact on farmers’ situation have become the subject of vast interest among agricultural economists. However, there have been relatively few studies trying to quantitatively asses this issue. This paper analyses the impact of supply chain modernisation on dairy farmers in Poland. It is shown that joining the modern marketing channel positively affects farmers’ revenues. The decision to enter the modern channel is crucially dependent on access to funds and facilitated by having larger cow herds.Supply chain, restructuring, dairy sector, Poland, Agribusiness, Livestock Production/Industries,
Supplemental material for Fitting mechanistic epidemic models to data: A comparison of simple Markov chain Monte Carlo approaches
No full textSupplemental material for Fitting mechanistic epidemic models to data: A comparison of simple Markov chain Monte Carlo approaches by Michael Li, Jonathan Dushoff and Benjamin M Bolker in Statistical Methods in Medical Research</p
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