Path, theme and narrative in open plan exhibition settings

Three arguments are made based on the analysis of science exhibitions. First,sufficiently refined techniques of spatial analysis allow us to model the impact oflayout upon visitors' paths, even in moderately sized open plans which allow almostrandom patterns of movement and relatively unobstructed visibility. Second, newlydeveloped or adapted techniques of analysis allow us to make a transition frommodeling the mechanics of spatial movement (the way in which movement is affectedby the distribution of obstacles and boundaries), to modeling the manner in whichmovement might register additional aspects of visual information. Third, theadvantages of such purely spatial modes of analysis extend into providing us with asharper understanding of some of the pragmatic constrains within which exhibitioncontent is conceived and designed

Creation of an ultra scale-down bioreactor mimic for rapid development of lignocellulosic enzymatic hydrolysis processes

BACKGROUND Cellulosic bioethanol processes involve several steps, all of which require experimental optimisation. A significant aid to this research would be a validated ultra scale-down (USD) model that could be used to perform rapid, wide ranging screening and optimisation experiments using limited materials under process relevant conditions. RESULTS In this work, the use of 30 mL shaken conical tubes as a USD model for an enzymatic hydrolysis process is established. The approach is demonstrated for the hydrolysis of distillers' dried grains with solubles (DDGS). Results from the USD tubes closely mimic those obtained from 4 L stirred tanks, in terms of the rate, composition and concentrations of sugars released, representing an 80-fold scale reduction. The utility of the USD approach is illustrated by investigating factors that may be limiting hydrolysis yields at high solids loadings. Washing the residual solids periodically during hydrolysis allowed 100% of the available sugar to be hydrolysed using commercially available enzymes. CONCLUSION The results demonstrate that the USD system reported successfully mimics the performance of conventional stirred tanks under industrially relevant conditions. The utility of the system was confirmed through its use to investigate performance limitation using a commercially relevant feedstock

Higgsless GUT Breaking and Trinification

Boundary conditions on an extra-dimensional interval can be chosen to break bulk gauge symmetries and to reduce the rank of the gauge group. We consider this mechanism in models with gauge trinification. We determine the boundary conditions necessary to break the trinified gauge group directly down to that of the standard model. Working in an effective theory for the gauge symmetry-breaking parameters on a boundary, we examine the limit in which the GUT-breaking sector is Higgsless and show how one may obtain the low-energy particle content of the minimal supersymmetric standard model. We find that gauge unification is preserved in this scenario, and that the differential gauge coupling running is logarithmic above the scale of compactification. We compare the phenomenology of our model to that of four-dimensional trinified theories.Comment: 22 pages, LaTeX, 2 eps figures (v3: discussion of mass scales clarified

Spatiotemporal variability in the O-18-salinity relationship of seawater across the tropical Pacific Ocean

The relationship between salinity and the stable oxygen isotope ratio of seawater (δ18Osw) is of utmost importance to the quantitative reconstruction of past changes in salinity from δ18O values of marine carbonates. This relationship is often considered to be uniform across water masses, but the constancy of the δ18Osw-salinity relationship across space and time remains uncertain, as δ18Osw responds to varying atmospheric vapor sources and pathways, while salinity does not. Here we present new δ18Osw-salinity data from sites spanning the tropical Pacific Ocean. New data from Palau, Papua New Guinea, Kiritimati, and Galápagos show slopes ranging from 0.09 ‰/psu in the Galápagos to 0.32‰/psu in Palau. The slope of the δ18Osw-salinity relationship is higher in the western tropical Pacific versus the eastern tropical Pacific in observations and in two isotope-enabled climate model simulations. A comparison of δ18Osw-salinity relationships derived from short-term spatial surveys and multiyear time series at Papua New Guinea and Galápagos suggests spatial relationships can be substituted for temporal relationships at these sites, at least within the time period of the investigation. However, the δ18Osw-salinity relationship varied temporally at Palau, likely in response to water mass changes associated with interannual El Niño–Southern Oscillation (ENSO) variability, suggesting nonstationarity in this local δ18Osw-salinity relationship. Applying local δ18Osw-salinity relationships in a coral δ18O forward model shows that using a constant, basinwide δ18Osw-salinity slope can both overestimate and underestimate the contribution of δ18Osw to carbonate δ18O variance at individual sites in the western tropical Pacific.We are grateful for the dedicated water samplers who enabled this research: Lori J. Bell and Gerda Ucharm of the Coral Reef Research Foundation, Palau; Rosa Maritza Motoche Gonzalez and the Fuerza Aerea Ecuatoriana, Santa Cruz, Galapagos, Ecuador; Taonateiti Kabiri and the students of Tennessee Primary School, London, Kiritimati; and the Manus Weather Observers, U.S. Department of Energy ARM Climate Research Facility, Manus, Papua New Guinea. We would like to thank the Galapagos National Park, the Kiritimati Ministry of Environment Lands and Agricultural Development for sample permits, and the Charles Darwin Research Station for logistical support. Funding sources for this work includes NSF-AGS-PF 1049664 to J.L.C., NSF P2C2-1203785 to K.M.C., J.L.C., and D.N. This research was also supported by the Office of Biological and Environment Research of the U.S. Department of Energy as part of the Atmospheric Radiation Measurement Climate Research Facility. Isotope data are available as supporting information associated with the manuscript. (1049664 - NSF-AGS-PF; P2C2-1203785 - NSF; Office of Biological and Environment Research of the U.S. Department of Energy as part of the Atmospheric Radiation Measurement Climate Research Facility

Annular Lichen Planus with Central Clearing

Annular lichen planus is an uncommon clinical variant of lichen planus. Characteristics include an annular configuration associated with a narrow rim of erythema and inflammation and a depressed center. There is a tendency toward central clearing. We present an illustrative case of annular lichen planus in an 82-year-old woma

On the Formation of Multiple Stellar Populations in Globular Clusters

Nearly all globular clusters (GCs) studied to date show evidence for multiple stellar populations, in stark contrast to the conventional view that GCs are a mono-metallic, coeval population of stars. Building on earlier work, we propose a simple physical model for the early evolution (several 10^8 yr) of GCs. We consider the effects of stellar mass-loss, type II and prompt type Ia supernovae, ram pressure, and accretion from the ambient ISM on the development of a young GC's own gas reservoir. In our model, type II SNe from a first generation of star formation clears the GC of its initial gas reservoir. Over the next several 10^8 yr, mass lost from AGB stars and matter accreted from the ambient ISM collect at the center of the GC. This material must remain quite cool (T~10^2K), but does not catastrophically cool on a crossing time because of the high Lyman-Werner flux density in young GCs. The collection of gas within the GC must compete with ram pressure from the ambient ISM. After several 10^8 yr, the Lyman-Werner photon flux density drops by more than three orders of magnitude, allowing molecular hydrogen and then stars to form. After this second generation of star formation, type II SNe from the second generation and then prompt type Ia SNe associated with the first generation maintain a gas-free GC, thereby ending the cycle of star formation events. Our model makes clear predictions for the presence or absence of multiple stellar populations within GCs as a function of GC mass and formation environment. Analyzing intermediate-age LMC clusters, we find evidence for a mass threshold of ~10^4 Msun below which LMC clusters appear to be truly coeval. This threshold mass is consistent with our predictions for the mass at which ram pressure is capable of clearing gas from clusters in the LMC at the present epoch. (ABRIDGED)Comment: 13 pages, 5 figures, ApJ in pres