Mapping the Self: Reconciling Identity through an Expansion of the American Road Genre

This thesis explores the American road genre. I argue that in addition to the automobile and the highway, a discussion of trains, boats, and walkers and their alternative roads must also be included in the genre. Each method of transportation expands the genre by adding new themes and ideas. Hobos and tramps can take to the road in search of community in order to discover more about themselves; some boatmen can use America’s racial history to discover themselves; walkers can go through a state of liminality in order to discover their internal selves. When these travelers complete their journeys, many are unsuccessful and either return home disappointed or do not return home at all

1995, Spatial and temporal variability of late Neogene equatorial Pacific carbonate

High-resolution, continuous records of GRAPE wet bulk density (a carbonate proxy) from Ocean Drilling Program Leg 138 provide one the opportunity for a detailed study of eastern equatorial Pacific Ocean carbonate sedimentation during the last 6 m.y. The transect of sites drilled spans both latitude and longitude in the eastern equatorial Pacific from 90° to 110°W and from 5°S to 10°N. Two modes of variability are resolved through the use of Empirical Orthogonal Function (EOF) analysis. In the presence of large tectonic and climatic boundary condition changes over the last 6 m.y., the dominant mode of spatial variability in carbonate sedimentation is remarkably constant. The first mode accounts for over 50% of the variance in the data, and is consistent with forcing by equatorial divergence. This mode characterizes both carbonate concentration and carbonate mass accumulation rate time series. Variability in the first mode is highly coherent with insolation, indicating a strong linear relationship between equatorial Pacific car bonate sedimentation and Milankovitch variability. Frequency domain analysis indicates that the coupling to equatorial divergence in carbonate sedimentation is strongest in the precession band (19-23 k.y.) and weakest though present at lower frequencies. The second mode of variability has a consistent spatial pattern of east-west asymmetry over the past 4 m.y. only; prior to 4 Ma, a different mode of spatial variability may have been present, possibly suggesting influence by closure of the Isthmus of Panama or other tectonic changes. The second mode of variability may indicate influence by CaCO3 dissolution. The second mode of variability is not highly coherent with insolation. Comparison of the modes of carbonate variability to a 4 m.y. record of benthic δ 1 8 indicates that although overall correlation between carbonate and δ 1 8 is low, both modes of variability in carbonate sedimentation are coherent with δ 1 8 changes at some frequencies. The first mode of carbonate variability is coherent with Sites 846/849 δ 1 8 at the dominant insolation periods, and the second mode is coherent at 100 k.y. during the last 2 m.y. The coherence between carbonate sedimentation and δ 1 8 in both EOF modes suggests that multiple uncorrelated modes of variability operated within the climate system during the late Neogene

Art and New Media

No abstract available

Appropriation and the Art of the Copy

This essay focuses on why and how copying occurs within the field of visual art and identifies shifts in the perception of the role of copying over time as indicated by changing terminology. Copies are ubiquitous in our culture today. They are especially prevalent on the Internet in the form of mash-ups and memes. While appropriation (the quoting or borrowing of an earlier artist\u27s work or style) is generally considered a postmodern strategy, the practice has, in fact, a long and complicated history that includes the tradition of academic copying (a method of artistic training whereby students copy the works of masters) as well as the history of art forgery. The development of technology that made copying easier, notably photography, and more recently digital editing programs such as Photoshop, have altered the perception of the copy in relation to so-called original artwork. A gradual acceptance of multiple originals—common in printmaking, photography, and digital media, but also in the history of sculpture—also contributed to the evolution of artistic and social views on copying. Cultural appropriation (borrowing across cultures) and transcultural appropriation (back-and-forth or multiple levels of cultural exchange) are important parallel developments. During the colonial period, works from China, Japan, and Africa influenced Western artists now considered to be the paragons of the avant-garde (e.g., Édouard Manet, Vincent van Gogh, and Pablo Picasso). Colonialism also shaped museum collections around the world as functional and sometimes sacred objects were acquired and reclassified as art. In the postcolonial period, artists from colonized and colonizing cultures wrestled with this history—at this writing, this latter development is ongoing

Aridification of Central Asia and uplift of the Altai and Hangay mountains, Mongolia: stable isotope evidence

Central Asia has become increasingly arid during the Cenozoic, though the mechanisms behind this aridification remain unresolved. Much attention has focused on the influence and uplift history of the Tibetan Plateau. However, the role of ranges linked to India-Asia convergence but well north of the Plateau—including the Altai, Sayan, and Hangay—in creating the arid climate of Central Asia is poorly understood. Today, these ranges create a prominent rain shadow, effectively separating the boreal forest to the north from the deserts of Central Asia. To explore the role of these mountains in modifying climate since the late Eocene, we measured carbon and oxygen stable isotopes in paleosol carbonates from three basins along a 650 km long transect at the northern edge of the Gobi Desert in Mongolia and in the lee of the Altai and Hangay mountains. We combine these data with modern air-parcel back-trajectory modeling to understand regional moisture transport pathways at each basin. In all basins, δ¹³C increases, with the largest increase in western Mongolia. The first δ¹³C increase occurs in central and southwestern Mongolia in the Oligocene. δ¹³C again increases from the upper Miocene to the Quaternary in western and southwestern Mongolia. We use a 1-D soil diffusion model to demonstrate that these δ¹³C increases are linked to declines in soil respiration driven by dramatic increases in aridity. Using modern-day empirical relations between mean annual precipitation and soil respiration, we estimate that precipitation has likely more than halved over the Neogene. Given the importance of the Hangay and Altai in steering moisture in Mongolia, we attribute these changes to differential surface uplift of the Hangay and Altai. Surface uplift in the Hangay began by the early Oligocene, blocking Siberian moisture and aridifying the northern Gobi. In contrast, surface uplift of the Altai began in the late Miocene, blocking moisture from reaching western Mongolia. Thus, the northern Gobi became increasingly arid east to west since the late Eocene, likely driven by orographic development in the Hangay during the Oligocene and the Altai in the late Miocene through Pliocene

Climate response to the 8.2 ka event in coastal California

A fast-growing stalagmite from the central California coast provides a high-resolution record of climatic changes synchronous with global perturbations resulting from the catastrophic drainage of proglacial Lake Agassiz at ca. 8.2 ka. High frequency, large amplitude variations in carbon isotopes during the 8.2 ka event, coupled with pulsed increases in phosphorus concentrations, indicate more frequent or intense winter storms on the California coast. Decreased magnesium-calcium ratios point toward a sustained increase in effective moisture during the event, however the magnitude of change in Mg/Ca suggests this event was not as pronounced on the western North American coast as anomalies seen in the high northern latitudes and monsoon-influenced areas. Nevertheless, shifts in the White Moon Cave record that are synchronous within age uncertainties with cooling of Greenland, and changes in global monsoon systems, suggest rapid changes in atmospheric circulation occurred in response to freshwater input and associated cooling in the North Atlantic region. Our record is consistent with intensification of the Pacific winter storm track in response to North Atlantic freshwater forcing, a mechanism suggested by simulations of the last deglaciation, and indicates this intensification led to increases in precipitation and infiltration along the California coast during the Holocene

On acceptance conditions for membrane systems: characterisations of L and NL

In this paper we investigate the affect of various acceptance conditions on recogniser membrane systems without dissolution. We demonstrate that two particular acceptance conditions (one easier to program, the other easier to prove correctness) both characterise the same complexity class, NL. We also find that by restricting the acceptance conditions we obtain a characterisation of L. We obtain these results by investigating the connectivity properties of dependency graphs that model membrane system computations

Alkenone sea-surface temperatures and carbon burial at site 846 (Eastern Equatorial Pacific Ocean) : the last 1.3 M.Y.

We analyzed the unsaturation ratio (U k/37 ) of long-chain ketones—a molecular sea-surface temperature (SST) indicator—concentrations of carbonate and organic carbon in sediments from Site 846 in the eastern equatorial Pacific Ocean. Based on an isotopic age model for the composite depth section of 0-46 m below seafloor and on estimates of sediment density, accumulation rates of these biogenic compounds were calculated. Our combined temperature and biogenic flux record traces conditions at the origin of the South Equatorial Current over the last 1.3 m.y. S STs have fluctuated considerably over the interval studied. A long trend of gradual decrease from 24°C at 1.3 Ma ends between 500 and 400 Ka, when lowest values of 19°C were reached. Since this time, the temperature data indicate a warming trend to the Holocene modulated by high-amplitude variation (19° to 27°C). The inversion of the trend between 400 and 500 Ka coincides with maximal accumulation rates of carbonate, which since then have decreased. In contrast, organic carbon accumulation since then has increased in variability and in absolute values. On shorter time scales, the records show a strong link to the global climatic background. Since 1.3 Ma, carbonate (0.2-3 g/cm² k.y.¯¹) and organic carbon accumulation rates (2-30 mg/cm² k.y¯¹) were consistently high (more than twice their modern values and those of interglacials) during glacial maxima in the benthic isotope record, when temperatures were low. However, cross-spectral analyses with the δ¹⁸O record suggest that variation in organic carbon flux is not linked directly to variations in SST. Temperature maxima in our record led interglacial events by 7 k.y. in the 100-k.y. eccentricity cycle and by 5 k.y. in the 41-k.y. obliquity cycle. In contrast, maxima in organic carbon accumulation lag behind glacial maxima and low temperatures by 14 k.y. in the eccentricity cycle. On glacial/interglacial time scales, a prominent influence on SST—but not on organic carbon burial—at Site 846 appears to be the advection of cold water into the South Equatorial Current

Plasmas and Controlled Nuclear Fusion

Contains reports on five research projects.U. S. Atomic Energy Commission (Contract AT(30-1)-3980

Carbon 13 in Pacific Deep and Intermediate Waters, 0-370 ka: Implications for Ocean Circulation and Pleistocene CO2

Stable isotopes in benthic foraminifera from Pacific sediments are used to assess hypotheses of systematic shifts in the depth distribution of oceanic nutrients and carbon during the ice ages. The carbon isotope differences between ∼1400 and ∼3200 m depth in the eastern Pacific are consistently greater in glacial than interglacial maxima over the last ∼370 kyr. This phenomenon of “bottom heavy” glacial nutrient distributions, which Boyle proposed as a cause of Pleistocene CO2 change, occurs primarily in the 1/100 and 1/41 kyr−1 “Milankovitch” orbital frequency bands but appears to lack a coherent 1/23 kyr−1 band related to orbital precession. Averaged over oxygen-isotope stages, glacial δ13C gradients from ∼1400 to ∼3200 m depth are 0.1‰ greater than interglacial gradients. The range of extreme shifts is somewhat larger, 0.2 to 0.5‰. In both cases, these changes in Pacific δ13C distributions are much smaller than observed in shorter records from the North Atlantic. This may be too small to be a dominant cause of atmospheric pCO2 change, unless current models underestimate the sensitivity of pCO2 to nutrient redistributions. This dampening of Pacific relative to Atlantic δ13C depth gradient favors a North Atlantic origin of the phenomenon, although local variations of Pacific intermediate water masses can not be excluded at present