SAGE measurements of the stratospheric aerosol dispersion and loading from the Soufriere Volcano

Explosions of the Soufriere volcano on the Caribbean Island of St. Vincent reduced two major stratospheric plumes which the stratospheric aerosol and gas experiment (SAGE) satellite tracked to West Africa and the North Atlantic Ocean. The total mass of the stratospheric ejecta measured is less than 0.5% of the global stratospheric aerosol burden. No significant temperature or climate perturbation is expected. It is found that the movement and dispersion of the plumes agree with those deduced from high altitude meteorological data and dispersion theory. The stratospheric aerosol dispersion and loading from the Soufrier volcano was measured

Trends in aerosol abundances and distributions

The properties of aerosols that reside in the upper atmosphere are described. Special emphasis is given to the influence these aerosols have on ozone observation systems, mainly through radiative effects, and on ambient ozone concentrations, mainly through chemical effects. It has long been appreciated that stratospheric particles can interfere with the remote sensing of ozone distribution. The mechanism and magnitude of this interference are evaluated. Separate sections deal with the optical properties of upper atmospheric aerosols, long-term trends in stratospheric aerosols, perturbations of the stratospheric aerosol layer by volcanic eruptions, and estimates of the impacts that such particles have on remotely measured ozone concentrations. Another section is devoted to a discussion of the polar stratospheric clouds (PSC's). These unique clouds, recently discovered by satellite observation, are now thought to be intimately connected with the Antarctic ozone hole. Accordingly, interest in PSC's has grown considerably in recent years. This chapter describes what we know about the morphology, physical chemistry, and microphysics of PSC's

Human Apolipoprotein B Transgenic Mice Generated with 207- and 145-Kilobase Pair Bacterial Artificial Chromosomes. Evidence that a distant 5'-element confers appropriate transgene expression in the intestine

We reported previously that ~80-kilobase pair (kb) P1 bacteriophage clones spanning either the human or mouse apoB gene (clones p158 and p649, respectively) confer apoB expression in the liver of transgenic mice, but not in the intestine. We hypothesized that the absence of intestinal expression was due to the fact that these clones lacked a distant DNA element controlling intestinal expression. To test this possibility, transgenic mice were generated with 145- and 207-kb bacterial artificial chromosomes (BACs) that contained the human apoB gene and more extensive 5'- and 3'-flanking sequences. RNase protection, in situ hybridization, immunohistochemical, and genetic complementation studies revealed that the BAC transgenic mice manifested appropriate apoB gene expression in both the intestine and the liver, indicating that both BACs contained the distant intestinal element. To determine whether the regulatory element was located 5' or 3' to the apoB gene, transgenic mice were generated by co-microinjecting embryos with p158 and either the 5'- or 3'-sequences from the 145-kb BAC. Analysis of these mice indicated that the apoB gene's intestinal element is located 5' to the structural gene. Cumulatively, the transgenic mouse studies suggest that the intestinal element is located between -33 and -70 kb 5' to the apoB gene

Tropospheric Transmissivity Measurements Using the Raman Nitrogen Lidar Technique

LIDAR measurements in Azusa, California, during October 1972, were made in which the backscattered Raman-shifted nitrogen return was ratioed at different altitudes in order to obtain transmissivity. Rawinsonde data from nearby El Monte were used to determine the temperature and nitrogen number density altitude profiles. These data and other meteorological data are compared to the vertical aerosol and transmissivity structure determined by LIDAR. Also data analysis techniques are shown for obtaining q2 (transmissivity) and beta (attenuation coefficient) as a function of altitude

Global trends

Measuring trends in ozone, and most other geophysical variables, requires that a small systematic change with time be determined from signals that have large periodic and aperiodic variations. Their time scales range from the day-to-day changes due to atmospheric motions through seasonal and annual variations to 11 year cycles resulting from changes in the sun UV output. Because of the magnitude of all of these variations is not well known and highly variable, it is necessary to measure over more than one period of the variations to remove their effects. This means that at least 2 or more times the 11 year sunspot cycle. Thus, the first requirement is for a long term data record. The second related requirement is that the record be consistent. A third requirement is for reasonable global sampling, to ensure that the effects are representative of the entire Earth. The various observational methods relevant to trend detection are reviewed to characterize their quality and time and space coverage. Available data are then examined for long term trends or recent changes in ozone total content and vertical distribution, as well as related parameters such as stratospheric temperature, source gases and aerosols

Resolving singular forces in cavity flow: Multiscale modeling from atoms to millimeters

A multiscale approach for fluid flow is developed that retains an atomistic description in key regions. The method is applied to a classic problem where all scales contribute: The force on a moving wall bounding a fluid-filled cavity. Continuum equations predict an infinite force due to stress singularities. Following the stress over more than six decades in length in systems with characteristic scales of millimeters and milliseconds allows us to resolve the singularities and determine the force for the first time. The speedup over pure atomistic calculations is more than fourteen orders of magnitude. We find a universal dependence on the macroscopic Reynolds number, and large atomistic effects that depend on wall velocity and interactions.Comment: 4 pages,3 figure

Probing the N=14N = 14 subshell closure: gg factor of the 26^{26}Mg(21+^+_1) state

The first-excited state $g$~factor of $^{26}$Mg has been measured relative to the $g$ factor of the $^{24}$Mg($2^+_1$) state using the high-velocity transient-field technique, giving $g=+0.86\pm0.10$. This new measurement is in strong disagreement with the currently adopted value, but in agreement with the $sd$-shell model using the USDB interaction. The newly measured $g$ factor, along with $E(2^+_1)$ and $B(E2)$ systematics, signal the closure of the $\nu d_{5/2}$ subshell at $N=14$. The possibility that precise $g$-factor measurements may indicate the onset of neutron $pf$ admixtures in first-excited state even-even magnesium isotopes below $^{32}$Mg is discussed and the importance of precise excited-state $g$-factor measurements on $sd$~shell nuclei with $N\neq Z$ to test shell-model wavefunctions is noted.Comment: 8 pages, 5 figure

Place matters: but does local leadership?

The arrival of New Labour into Government witnessed the prominent re-emergence of place onto the policy agenda. This heralded a range of area-based-initiatives designed to both tackle neighbourhood forms of deprivation and to re-establish a sense of identity and connection between individuals and their local community. In terms of place-making, effective and inclusive participation, representation and leadership were all identified as prerequisites for the creation of sustainable communities . But how important is local leadership and strategic vision within local public service organisations in achieving the desired place-making outcomes? This paper examines the extent to which local leadership and strategic vision represents a significant factor in promoting higher levels of satisfaction, belonging, cohesion and participation across single tier councils in England. The ensuing empirical evidence raises significant questions not only about the importance of local leadership in place-making, but also the environmental and organizational factors that shape local places