Nixon studies

Most methods of testing bond type involve the motion of nuclei. The chemical method, such as substitution at positions adjacent to a hydroxyl group in testing for double-bond character, as used in the Mills-Nixon studies, is one of these. This method gives only the resultant bond type over the period required for the reaction to take place. Since this period is much longer than that of ordinary electronic resonance, the chemical method cannot be used in general to test for the constituent structures of a resonating molecule. Only in case that the resonance frequency is very small (less than the frequencies of nuclear vibration) can the usual methods be applied to test for the constituent structures and in this case the boundary between resonance and tautomerism is approached or passed. 

Since Mills and Nixon studied in their original paper hydroxy derivates of fused aromatic systems like /3-hydroxyindan [1], we examined a series of model compounds possessing OH group attached at the /3-position [14], It was found that the hydroxy group exerted overwhelming influence on the electrophilic susceptibility of the aromatic carbons by substantial activation of its ortho positions. However, the free /3 position is the most active one because of the Mills-Nixon effect, which amplifies the OH inductive effect. Hence the selectivity in the electrophilic substitution reactions is governed once again by the MN effect [14]. 

Zecchin AC, Simpson AR, Maier HR, Nixon JB (2005) Parametric study for an ant algorithm applied to water distribution system optimization, IEEE Trans. Evol Comput 9 175-190... 

Olafsson M, Eggler DH (1983) Phase relations of amphibole, amphibole-carbonate, and phlogopite-carbonate peridohte petrologic constraints on the asthenosphere. Earth Planet Sci Lett 64 305-315 Olson P, Schubert G, Anderson C, Goldman P (1988) Plume formahon and lithosphere erosion a comparison of laboratory and numerical experiments. J Geophys Res 93 15065-15084 Pearson DG, Shirey SB, Carlson RW, Boyd FR, Nixon PH (1995) Stabilisahon of Archean lithospheric manhe A Re-Os isotope isotope study of peridohte xenoliths. Earth Planet Sci Lett 134 341-357... 

Nixon Several years ago a study showed there were 10 times more InsP3 receptors than RyRs in the guinea-pig intestinal smooth muscle (Wibo Godfraind 1994). We have found in most smooth muscles that there are fewer RyRs. 

Salamy, S. G. and Nixon, J. C., 1954. Reaction between a mercury surface and some flotation reagents an electrochemical study. Aust. J. Chem., 7 146- 156 Salvador, P. and Tafalla, D., 1991. Reaction Mechanism at -FeS2/I interface. Journal of the Electrochemical Society, 132(6) 1350- 1356... 

Childers DL, Day JW, McKellar HN. 2000. Twenty more years of marsh and estuarine flux studies revisiting Nixon (1980). In Weinstein MP, Kreeger DA, eds. Concepts and Controversies in Tidal Marsh Ecology. Dordrecht Kluwer, 389-421. 

The point group of the molecule is probably Cj 24-426) distances between the nuclei, calculated from the force constants, are cf(P—P) = 2.11 A and rf(P-H) = 1.44 The IR and Raman spectra of diphosphine were carefully studied by Baudler and Schmidt and by Nixon and the n.m.r spectra by Lynden-Bell. ... 

To study the effect of ring strain (Mills-Nixon effect) on the properties of five-membered heteroaromatics, Wynberg and Zwanenburg developed a new synthesis of l/f,3H-thieno[3,4-c]thiophene (112) [Eq. (37)]. They obtained 3,4-dimethylthiophene-2,5-dicarboxylate (113) by... 

This paper records the results of a similar study of the bond structure of tetrahydronaphthalene and a comparison of these results with our earlier work on indan and o-xylene [lc], thus permitting a rather comprehensive evaluation of the Mills-Nixon effect. What is believed to be a novel steric effect on intramolecular hydrogen bonding also will be described. 

Work on the Mills-Nixon effect has been reviewed by Badger [2]. Most of the experimental work done in this field has involved a study of relative chemical reactivities and hence is subject to the severe limitations mentioned earlier [ lc]. From a study of the ease with which the benzoates of isomeric hydroxy-5,6,7,8-tetrahydroacetonaphthones underwent the Baker-Venkataraman transformation O Farrell et ah [3] recently concluded that the 1,2-bond of 5,6,7,8-tetrahydro-naphthalene has a higher bond order than the 2,3-bond. Similar work also led these authors to conclude that the 4,5-bond in indan is of higher order than the 5,6-bond. These workers did not attempt to assess the extent of the difference in bond order presumably exhibited by the bonds in question. 

The increased input of nutrients and other pollutants to rivers and estuaries may have been exacerbated by the destruction of large areas of fresh and salt water wetlands, often for agriculture (Figs 2 and 3). For example, in the United States, in 1950 there were over 100,000,000 acres (over tOx I0 > hectares) of wetlands being drained (Shaw and Fredine, 1956). The impact of wetlands on water quality is difficult to quantify (Nixon, 1980), but the few annual mass balance studies that are available indicate that these environments serve as sinks (though of widely varying strength) for nutrients (Fig. 4) and a number of... 

Fig. 4. The results of annual mass balance studies for a number of fresh and salt water wetland areas receiving different levels of nutrient input. From Nixon and Lee (in press).

Kelly, 3.R. and Nixon, S.W., 1984. Experimental studies of the effect of organic deposition on the metabolism of a coastal marine bottom community. Mar. Ecol. Prog. Ser., 17 (2) 157-169. 

Kremer, 3.N. and Nixon, S.W., 1978. A coastal Marine Ecosystem, Simulation and Analysis. Ecological Studies 24, Springer-Verlag, NY, 217p. 

Nixon, S.W., Pilson, M.E.Q., Oviatt, C.A., Donaghay, P., Sullivan, B., Seitzinger, S., Rudnick, D. and Frithsen, 3., 1984. Eutrophication of a Coastal Marine Ecosystem- An experimental study using the MERL microcosms. In M.3.R. Fasham (ed.), Flows of Energy and Materials in Marine Ecosystems. Plenum Publishing Corporation, NY, pp. 105-135. 

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