SLMMARYAn analysis is made of the Monin-Obukhov function @.*I in the familiar wind profile equation, using data from two recent expeditions to Gurley (New South Wales) and Hay (New South Wales). In one, the friction velocity u1 is determined directly by the eddy correlation method, and in the other, conducted during mid-winter when small heat-fluxes were experienced, by the use of a friction coefficient applied to a low-!eve1 wind.By collating with a similar earlier analysis for heat and water vapour transfer, the variations of @.u, and @w with stability are presented in tabular torm in the z / L range --0.01 to -1.0. Within this range thc empirical relationships @JI = (1 -16 z/L)-i and @ H , IV -( 1 -16 z/L)-f, and the implied equality between Ri and z/L, are found to approximate the data to within a few per-cent. 1067 1% 1970 KEFERENCES ' Transfer of momentum and heat in the planetary boundary layer,' Proceedings of the Symposium on Arctic Heat Budget and Atmospheric Circulation (The Rand Chporation), pp. 305-332. ' Wind profiles and the shearing stressan anomaly resolved,' Quart. J. R. Met. Soc., 83, pp. 537-540. ' T h e turbulent transport of heat and water vapour in an unstable atmosphere,' Ibid., 93, pp. 501-5OX. The Fluxatron -A revised approach to the measurement of eddy fluxes in the lower atmosphere,' J. Appl. Met., 6, pp. 408-113.' The measurement of atmospheric fluxes near the surface :A generalized approach,' Ibid., (in press).' The eddy-correlation technique of evaporation measurement using a sensitized quartz-crystal hygrometer.'Submitted to J. Appl. Met. ' The structure of atmospheric turbulence,' Interscience Monographs and Texts in I'hysics and Astronomy, Vol.
An extensive micrometeorological data set from the 1976 International Turbulence Comparison Experiment (IKE)is analysed to determine flux-gradient relationships in an unstable atmosphere for momentum, sensible heat and water vapour transfers. The data are first analysed for internal consistency, resulting in the rejection of some data. Following a least-square tit to the remaining data in the form 4/k = (1 -az/L)-@/k, rounded-off values of k, 4 and j3 are selected for each form of transfer consistent with the statistical accuracy of the measurements. The equations fiilally adopted are and 4~ = (1 -28z/L)-"4 4H.W = (1 -14z/L)-"2 with k, = k" = k, = 0.40.These expressions fit the averaged observations to within a few per cent in the stability range of the experiment ( -4 < z/L < -0.004).
Close to 50 % of the human genome harbors repetitive sequences originally derived from mobile DNA elements, and in normal cells this sequence compartment is tightly regulated by epigenetic silencing mechanisms involving chromatin-mediated repression. In cancer cells, repetitive DNA elements suffer abnormal demethylation, with potential loss of silencing. We used a genome-wide microarray approach to measure DNA methylation changes in cancers of the head and neck, and to compare these changes to alterations found in adjacent non-tumor tissues. We observed specific alterations at thousands of small clusters of CpG dinucletides associated with DNA repeats. Among the 257,599 repetitive elements probed, 5 to 8% showed disease-related DNA methylation alterations. In dysplasia, a large number of local events of loss of methylation appear in apparently stochastic fashion. Loss of DNA methylation is most pronounced for certain members of the SVA, HERV, LINE-1P, AluY, and MaLR families. The methylation levels of retrotransposons are discretely stratified, with younger elements being highly methylated in healthy tissues, while in tumors these young elements suffer the most dramatic loss of methylation. Wilcoxon test statistics reveal that a subset of primate LINE-1 elements is demethylated preferentially in tumors, as compared to nontumoral adjacent tissue. Sequence analysis of these strongly demethylated elements reveals genomic loci harboring full-length, as opposed to truncated elements, while possible enrichment for functional LINE-1 ORFs is weaker. Our analysis suggests that in non-tumor adjacent tissues there is generalized and highly variable disruption of epigenetic control across the repetitive DNA compartment, while in tumor cells a specific subset of LINE-1 retrotransposons that arose during primate evolution suffers the most dramatic DNA methylation alterations.
SUMMARYMicro-meteorological data acquired during five expeditions to carefully chosen sites are analysed to determine the flux-gradient relation for the transfer of heat and water vapour in the lower atmosphere. The analysis takes the form of a direct assessment of the Monin-Obukhov universal functions QH and 4~. Data for +H were available from all five expeditions, and for QW from two of these.It was found that +H = Qw over the whole of the z/L range available, indicating an identity in mechanism for the turbulent transport of heat and water vapour over a freely evaporating surface. Over the range 0.02 < Iz/LI < 0.6, both 4~ and +w were found to vary approximately as 1zILI-f. In this range of Iz/L(, Priestley's H" was assessed as 1.15 f 0.07 and Crawford's E" as 1.10 f 0.12. This value of H* leads to the formulae H = 21.2 AB3lZ and E = 51.7 Aq A@ where E and H are in mWcm-*, A 0 is the potential temperature difference ("C) and Aq the specific humidity difference (gm kg-') between 1 and 4 metres height.Insufficient data limited the value of the corresponding analysis for Qw. Excellent agreement was found between the +H and Qw data, and +-curves For lz/Ll > 0.2, QH was found to vary as Iz/LI-).
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