Andrean examples of mega-geomorphology themes

Geomorphic (or physiographic) provinces have been a well known and useful method of regional landform classification for a century. Every earth scientist will recognize a phrase such as Appalachian Plateau or Southern Rocky Mountains as defining a discrete region of consistent geologic structure that has experienced a similar interval of erosion by a similar process or set of processes. The geomorphic provinces formalized in the United States by Fenneman in the 1920's continue to be highly satisfactory even though some boundaries were only vaguely drawn. Mosaics of LANDSAT images illustrate better than any earlier maps the validity and coherence of Fenneman's provinces. The concept of geomorphic provinces has been used subconsciously or intuitively, to describe the relief of the ocean floor and the topography of the Moon and other planets

Mountain building processes in the Central Andes

False color composite images of the Thematic Mapper (TM) bands 5, 4, and 2 were examined to make visual interpretations of geological features. The use of the roam mode of image display with the International Imaging Systems (IIS) System 600 image processing package running on the IIS Model 75 was very useful. Several areas in which good comparisons with ground data existed, were examined in detail. Parallel to the visual approach, image processing methods are being developed which allow the complete use of the seven TM bands. The data was organized into easily accessible files and a visual cataloging of the quads (quarter TM scenes) with preliminary registration with the best available charts for the region. The catalog has proved to be a valuable tool for the rapid scanning of quads for a specific investigation. Integration of the data into a complete approach to the problems of uplift, deformation, and magnetism in relation to the Nazca-South American plate interaction is at an initial stage

Magnetic susceptibility of vanadium carbide

Magnetic susceptibility of vanadium carbide from 77 to 300 K measured by magnetomete

Hypotheses for near-surface exchange of methane on Mars

The Curiosity rover recently detected a background of 0.7 ppb and spikes of 7 ppb of methane on Mars. This in situ measurement reorients our understanding of the Martian environment and its potential for life, as the current theories do not entail any geological source or sink of methane that varies sub-annually. In particular, the 10-fold elevation during the southern winter indicates episodic sources of methane that are yet to be discovered. Here we suggest a near-surface reservoir could explain this variability. Using the temperature and humidity measurements from the rover, we find that perchlorate salts in the regolith deliquesce to form liquid solutions, and deliquescence progresses to deeper subsurface in the season of the methane spikes. We therefore formulate the following three testable hypotheses. The first scenario is that the regolith in Gale Crater adsorbs methane when dry and releases this methane to the atmosphere upon deliquescence. The adsorption energy needs to be 36 kJ/mol to explain the magnitude of the methane spikes, higher than existing laboratory measurements. The second scenario is that microorganisms convert organic matter in the soil to methane when they are in liquid solutions. This scenario does not require regolith adsorption, but entails extant life on Mars. The third scenario is that deep subsurface aquifers produce the bursts of methane. Continued in situ measurements of methane and water, as well as laboratory studies of adsorption and deliquescence, will test these hypotheses and inform the existence of the near-surface reservoir and its exchange with the atmosphere.Comment: Accepted for publication on Astrobiolog

The star-formation rate in the host of GRB 990712

We have observed the host galaxy of GRB 990712 at 1.4 GHz with the Australia Telescope Compact Array, to obtain an estimate of its total star-formation rate. We do not detect a source at the position of the host. The 2 sigma upper limit of 70 microJy implies that the total star-formation rate is lower than 100 Msun/yr, using conservative values for the spectral index and cosmological parameters. This upper limit is in stark contrast with recent reports of radio/submillimeter-determined star-formation rates of roughly 500 Msun/yr for two other GRB host galaxies. Our observations present the deepest radio-determined star-formation rate limit on a GRB host galaxy yet, and show that also from the unobscured radio point-of-view, not every GRB host galaxy is a vigorous starburst.Comment: A&A Letters, in press, 5 pages; a high-resolution color gif version of the paper figure is also supplie

Electrodeless discharge lamp is easily started, has high stability

Electrodeless discharge borosilicate glass lamp is used in various high-resolution optical systems. It is partially charged with krypton, contains small amounts of rubidium, and is enclosed in a hermetically sealed envelope that maintains the lamp at an optimum temperature during discharge. The lamp is quickly started by its excitation coil

1. A Brief Survey of Christendom, 500-1100

The towering institution of the Middle Ages was the Church. From birth until death both the highest lord and the lowest serf felt its influence in some way or another, directly or indirectly. After about the year 1000 all men in Western Europe, except for a few Jews and Muslims, were its members. They were expected to support the Church in every way. It was not possible for one with a secular turn of mind to go to the priest and ask, in effect, to have his name erased from the Church\u27s rolls. Even the passing of time was now reckoned from the supposed year of Christ\u27s birth, following the calculations of a sixth century monk. [excerpt

4. The Church\u27s Bid for Intellectual Leadership

We have already noted the Church\u27s claim to teach in all its fulness every doctrine that men ought to be brought to know, and that regarding things visible and invisible, in heaven and on earth. During the Dark Ages it was too busy with other problems to be able to concern itself much with education. While there were sporadic attempts earlier, it was only during the eleventh and twelfth centuries that the Church turned more seriously to the problem of educating its members. This work was carried on primarily in the monastery and cathedral schools. But, because the monasteries of this time were mainly concerned with their own internal problems of reform, and because they were ill-equipped to take care of students who might not be monastically minded, the work of education fell mainly on such cathedral schools as those at Canterbury, Paris, Chartres, and Toledo. [excerpt

2. Rome: Roman Civilization

For our purpose, the importance of the Romans lies in the fact that it was most directly from the ruins of their civilization that our own developed. Therefore, before completing the account of the decline and fall of their empire, we will consider the cultural contributions made by the Romans. The Romans were not great cultural innovators. During the early republic, they were a simple agricultural people who were isolated from the civilizations upon whom the Greeks had drawn as well as from the Greeks themselves. As they began to expand, they came into contact with the Greeks -- first in southern Italy and then in the Balkans -- and began appropriating from them. But this was not properly Greek (or Hellenic) Civilization from which they were borrowing. It was what is known as Hellenistic, and that requires some explanation. [excerpt

1. Introduction

Criticism of the methods and conclusions of the Enlightenment was initiated almost as soon as the movement itself had begun. It is for this reason that this chapter follows immediately after the one on the Enlightenment, rather than after the later chapters on nationalism, liberalism, industrialism, evolutionary biology, and the social sciences. These movements made their appearance during the latter part of the eighteenth century, but often served only to broaden and strengthen the earlier criticisms of the Enlightenment and the demands for a more adequate way of thinking than it offered. The movements of thought with which we are concerned in this chapter — evangelism, utilitarianism, romanticism, and idealism — started in the eighteenth century and became characteristic elements of Western culture during the first part of the nineteenth century. After about 1848 other currents of thought, mainly social and scientific, tended to supplant them. [excerpt