Path dependence and Britain’s "coal wagon problem"

This article explores the nature and impact of path dependence in British rail coal haulage before 1939. It examines the factors which locked Britain's railways into a system of small coal wagons with highly fragmented ownership, the cost penalties of this system, and the reasons that attempts at modernization were unsuccessful. The analysis highlights the importance of decentralized ownership of a highly durable installed base of complementary infrastructure. Technical and institutional interrelatedness blocked incremental modernization, while the political requirement to compensate private wagon owners for the loss of their wagon stock made wholesale rationalization financially unattractive.

PPARγ2 gene Pro12Ala and PPARα gene Leu162Val single nucleotide polymorphisms interact with dietary intake of fat in determination of plasma lipid concentrations

Background/Aims: The peroxisome proliferator-activated receptors (PPARs) are transcriptional regulators of lipid metabolism, activated by unsaturated fatty acids. We investigated independent and interactive effects of PPARγ2 gene PPARG Pro12Ala (rs1801282) andPPARαgene PPARA Leu162Val (rs1800206) genotypes with dietary intake of fatty acids on concentrations of plasma lipids in subjects of whom 47.5% had metabolic syndrome. Methods: The RISCK study is a parallel design, randomised controlled trial. Plasma lipids were quantified at baseline after a 4-week high saturated fatty acids diet and after three parallel 24-week interventions with reference (high saturated fatty acids), high monounsaturated fatty acids and low-fat diets. Single nucleotide polymorphisms were genotyped in 466 subjects. Results: At baseline, the PPARG Ala12allele was associated with increased plasma total cholesterol (n = 378; p = 0.04), LDL cholesterol (p = 0.05) and apoB (p =0.05) after adjustment for age, gender and ethnicity. At baseline, PPARA Leu162Val × PPARG Pro12Ala genotype interaction did not significantly influence plasma lipid concentrations. After dietary intervention, gene-gene interaction significantly influenced LDL cholesterol (p =0.0002) and small dense LDL as a proportion of LDL (p = 0.005) after adjustments. Conclusions: Interaction between PPARG Pro12Ala and PPARA Leu162Valgenotypes may influence plasma LDL cholesterol concentration and the proportion as small dense LDL after a high monounsaturated fatty acids diet.

Effect of processed and red meat on endogenous nitrosation and DNA damage

Haem in red meat (RM) stimulates the endogenous production of mutagenic nitroso compounds (NOC). Processed (nitrite-preserved red) meat additionally contains high concentrations of preformed NOC. In two studies, of a fresh RM versus a vegetarian (VEG) diet (six males and six females) and of a nitrite-preserved red meat (PM) versus a VEG diet (5 males and 11 females), we investigated whether processing of meat might increase colorectal cancer risk by stimulating nitrosation and DNA damage. Meat diets contained 420 g (males) or 366 g (females) meat/per day. Faecal homogenates from day 10 onwards were analysed for haem and NOC and asso- ciated supernatants for genotoxicity. Means are adjusted for differ- ences in male to female ratios between studies. Faecal NOC concentrations on VEG diets were low (2.6 and 3.5 mmol/g) but significantly higher on meat diets (PM 175 ± 19 nmol/g versus RM 185 ± 22 nmol/g; P 5 0.75). The RM diet resulted in a larger pro- portion of nitrosyl iron (RM 78% versus PM 54%; P < 0.0001) and less nitrosothiols (RM 12% versus PM 19%; P < 0.01) and other NOC (RM 10% versus PM 27%; P < 0.0001). There was no statis- tically significant difference in DNA breaks induced by faecal water (FW) following PM and RM diets (P 5 0.80). However, PM re- sulted in higher levels of oxidized pyrimidines (P < 0.05). Surpris- ingly, VEG diets resulted in significantly more FW-induced DNA strand breaks than the meat diets (P < 0.05), which needs to be clarified in further studies. Meats cured with nitrite have the same effect as fresh RM on endogenous nitrosation but show increased FW-induced oxidative DNA damage.

Synthesis and characterization of nickel(II) and copper(II) complexes with tetradentate Schiff base ligands

The 1:1 condensation of 1,2-diaminopropane and 1-phenylbutane-1,3-dione at high dilution gives a mixture of two positional isomers of terdentate mono-condensed Schiff bases 6-amino-3-methyl-1-phenyl-4-aza-2-hepten-1-one (HAMPAH) and 6-amino-3,5-dimethyl-1-phenyl-4-aza-2-hexen-1-one (HADPAH). The mixture of the terdentate ligands has been used for further condensation with pyridine-2-carboxaldehyde or 2-acetylpyridine to obtain the unsymmetrical tetradentate Schiff base ligands. The tetradentate Schiff bases are then allowed to react with the methanol solution of copper(II) and nickel(II) perchlorate separately. The X-ray diffraction confirms the structures of two of the complexes and shows that the condensation site of the diamine with 1-phenylbutane-1,3-dione is the same.

Homoleptic copper(II) and copper(I) complexes of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline. Six-coordinate copper(I) in solution

Reaction of 5,6-dihydro-5,6-epoxy-1,10-phenanthroline (L) with Cu(ClO(4))(2)center dot 6H(2)O in methanol in 3:1 M ratio at room temperature yields light green [CuL(3)](ClO(4))(2)center dot H(2)O (1). The X-ray crystal structure of the hemi acetonitrile solvate [CuL(3)](ClO(4))(2)center dot 0.5CH(3)CN has been determined which shows Jahn-Teller distortion in the CuN(6) core present in the cation [CuL(3)](2+). Complex 1 gives an axial EPR spectrum in acetonitrile-toluene glass with g(parallel to) = 2.262 (A(parallel to) = 169 x 10 (4) cm (1)) and g(perpendicular to) = 2.069. The Cu(II/I) potential in 1 in CH(2)Cl(2) at a glassy carbon electrode is 0.32 V versus NHE. This potential does not change with the addition of extra L in the medium implicating generation of a six-coordinate copper(I) species [CuL(3)](+) in solution. B3LYP/LanL2DZ calculations show that the six Cu-N bond distances in [CuL(3)](+) are 2.33, 2.25, 2.32, 2.25, 2.28 and 2.25 angstrom while the ideal Cu(I)-N bond length in a symmetric Cu(I)N(6) moiety is estimated as 2.25 angstrom. Reaction of L with Cu(CH(3)CN)(4)ClO(4) in dehydrated methanol at room temperature even in 4:1 M proportion yields [CuL(2)]ClO(4) (2). Its (1)H NMR spectrum indicates that the metal in [CuL(2)](+) is tetrahedral. The Cu(II/I) potential in 2 is found to be 0.68 V versus NHE in CH(2)Cl(2) at a glassy carbon electrode. In presence of excess L, 2 yields the cyclic voltammogram of 1. From (1)H NMR titration, the free energy of binding of L to [CuL(2)](+) to produce [CuL(3)](+) in CD(2)Cl(2) at 298 K is estimated as -11.7 (+/-0.2) kJ mol (1).

Trinuclear and tetranuclear adduct formation between sodium perchlorate and copper(II) complexes of salicylaldimine type ligands: structural characterization and theoretical investigation

The synthesis of two new sodium perchlorate adducts (1:2 and 1:3) with copper(II) "ligand-complexes'' is reported. One adduct is trinuclear [(CuL(1))(2)NaClO(4)] (1) and the other is tetranuclear [(CuL(2))(3)Na]ClO(4)center dot EtOH (2). The ligands are the tetradentate di-Schiff base of 1,3-propanediamines and salicylaldehyde (H(2)L(1)) or 2-hydroxyacetophenone (H(2)L(2)). Both complexes have been characterized by X-ray single crystal structure analyses. In both structures, the sodium cation has a six-coordinate distorted octahedral environment being bonded to four oxygen atoms from two Schiff-base complexes in addition to a chelated perchlorate anion in 1 and to six oxygen atoms from three Schiff-base complexes in 2. We have carried out a DFT theoretical study (RI-B97-D/def2-SVP level of theory) to compute and compare the formation energies of 1:2 and 1:3 adducts. The DFT study reveals that the latter is more stabilized than the former. The X-ray crystal structure of 1 shows that the packing of the trinuclear unit is controlled by unconventional C-H center dot center dot center dot O H-bonds and Cu(2+)-pi non-covalent interactions. These interactions explain the formation of 1 which is a priori disfavored with respect to 2.

Climatology and variability in the ECHO coupled GCM

ECHO is a new global coupled ocean-atmosphere general circulation model (GCM), consisting of the Hamburg version of the European Centre atmospheric GCM (ECHAM) and the Hamburg Primitive Equation ocean GCM (HOPE). We performed a 20-year integration with ECHO. Climate drift is significant, but typical annual mean errors in sea surface temperature (SST) do not exceed 2° in the open oceans. Near the boundaries, however, SST errors are considerably larger. The coupled model simulates an irregular ENSO cycle in the tropical Pacific, with spatial patterns similar to those observed. The variability, however, is somewhat weaker relative to observations. ECHO also simulates significant interannual variability in mid-latitudes. Consistent with observations, variability over the North Pacific can be partly attributed to remote forcing from the tropics. In contrast, the interannual variability over the North Atlantic appears to be generated locally.

Species 2000 & ITIS Catalogue of Life, 2011 Annual Checklist

The Catalogue of Life: 2011 Annual Checklist contains contributions from 99 databases with information on 1,347,224 species and 92,306 infraspecific taxa, and also includes 895,441 synonyms and 366,401 common names

Low-cost momentum strategies

This paper analyses the impact of trading costs on the profitability of momentum strategies in the United Kingdom and concludes that losers are more expensive to trade than winners. The observed asymmetry in the costs of trading winners and losers crucially relates to the high cost of selling loser stocks with small size and low trading volume. Since transaction costs severely impact net momentum profits, the paper defines a new low-cost relative-strength strategy by shortlisting from all winner and loser stocks those with the lowest total transaction costs. While the study severely questions the profitability of standard momentum strategies, it concludes that there is still room for momentum-based return enhancement, should asset managers decide to adopt low-cost relative-strength strategies.