Search

For over a century, archaeologists have investigated the vast network of prehistoric Hohokam canal irrigation systems in the lower Salt River and middle Gila River valleys, as well as in other areas of southern Arizona. However, documentation of the agricultural fields in which prehistoric farmers irrigated their crops generally was lacking until the last 25 years. This is largely a result of the difficulty in identifying ancient fields, since they are not visible on the surface and have been obscured or destroyed by natural landscape processes as well as historic and modern disturbances. More recent archaeological investigations have revealed ancient irrigated fields through innovative methods and excavation techniques. The fields were constructed both by Hohokam irrigators (450–1450 CE) as well as by farmers from preceding cultural traditions during the Early Agricultural period (2100 BCE–50 CE). These discoveries occurred during projects conducted in compliance with the National Historic Preservation Act. In this chapter, I highlight these important studies that have expanded the view of ancient agricultural landscapes in southern Arizona. [ABSTRACT FROM AUTHOR]

Ethnohistorical and ethnographic observations from around the world indicate that projectiles were often made differently for warfare and hunting. Using experiential archaeology and analysis of a thousand years' worth of data from the middle Gila River in Arizona, the authors argue that side notched arrow points were produced for hunting large animals and were designed to be retrieved and reused, while unnotched points were intended for single use and for another purpose: to kill people. The data suggests furthermore that the region witnessed a steady increase in levels of violence during the period under study. Keywords: Gila River, Arizona, Archaic, pre-Classic, Classic, historic, flaked-stone projectile points, experimental archaeology, warfare, hunting, Introduction Ethnographic documentation from throughout the world indicates that stone projectile points were generally designed for hunting big game animals (>40kg) or for use in warfare, and arrow tips intended [...]

Worldwide applications of ochre analysis continue to develop at a rapid pace, highlighting a number of analytical and interpretative issues. As regional source databases continue to grow, researchers have turned to the thornier issues of source allocation. In this study, we utilize LA–ICP–MS and NAA to examine archaeological pigments, ceramic paints and experimental tiles from geological sources and Hohokam ceramics in central Arizona. Archaeological pigments and paint on sherds are successfully source matched based on trace element content, with implications for understanding paint production, sociocultural relations governing trade in pigment and the use of different resource landscapes over time. [ABSTRACT FROM AUTHOR]

Much of what is known regarding Historic period Native American communities is based on studying documents that were written by non-indigenous peoples. However, archaeological excavations in a portion of the Blackwater Village within the Gila River Indian Community provide another perspective on Native American life ways within south-central Arizona during the late 1800s. The latter nineteenth century was a pivotal time for the Akimel O'Odham (i.e., Pima) who have long lived within the Phoenix Basin, and they experienced dramatic changes in their subsistence strategies, settlement patterns, craft production, and other cultural practices during this time. These recent investigations demonstrate that the Akimel O'Odham were not passive recipients of Euroamerican culture, and instead they chose to adopt some aspects of non-native practices while at the same time retaining important traditions. As a result, the Akimel O'Odham have successfully maintained their society in the face of tremendous hardships, and Blackwater Village remains a vibrant settlement to this day. [ABSTRACT FROM AUTHOR]

Over the past 40+ years, III-V materials have been intensively studied for avalanche photodetectors, driven by applications including optical communications, imaging, quantum information processing, and autonomous vehicle navigation. Unfortunately, impact ionization is a stochastic process that introduces noise, thereby limiting sensitivity and achievable bandwidths, leading to intense effort to mitigate this noise through the identification of different materials and device structures. Exploration of these materials has seen limited success as it has proceeded in a largely ad hoc fashion due to little consensus regarding which fundamental properties are important. Here, we report an exciting step toward deterministic design of low-noise avalanche photodetector materials by alternating the composition at the monolayer scale; this represents a dramatic departure from previous approaches, which have concentrated on either unconventional compounds/alloys or nanoscale band-engineering. In particular, we demonstrate how to substantially improve upon the noise characteristics of the current state-of-the art telecom avalanche multipliers, In0.52Al0.48As grown on InP substrates, by growing the structure as a strain-balanced digital alloy of InAs and AlAs layers, each only a few atomic layers thick. The effective k-factor, which has historically been considered a fundamental material property, was reduced by 6–7× from k = 0.2 for bulk In0.52Al0.48As to k = 0.05 by using the digital alloy technique. We also demonstrate that these “digital alloys” can significantly extend the photodetector cutoff wavelength well beyond those of their random alloy counterparts. [ABSTRACT FROM AUTHOR]

Irragric anthrosols form as a result of prolonged deposition of fine sediments from irrigation water. Ancient irragric soils centuries to millennia old occur in several world regions, especially in arid environments of Asia and the Americas. This article presents evidence for an ancient irragric anthrosol in the North American Southwest, along the Snaketown Canal System in the Middle Gila River Valley, Arizona. This pedostratigraphic unit was formed as a result of a millennium of irrigation by Hohokam farmers from A.D. 450 to 1450. The irragric soil consists of a mantle of silty-to-loamy textures with minimal soil formation overlying a natural argillic horizon on a Pleistocene stream terrace. A soil mapped independently by the United States Department of Agriculture-Natural Resources Conservation Service with these horizons corresponds closely with the canal system. Soil within the canal system tends to be lower in salt, sodium, and pH compared with external soils. This suggests that the irragric process improved soil for crop production through long-term leaching and additions of fresh sediments with the irrigation water. This anthropogenic process of canal sedimentation has had a long-lasting impact on the sedimentary record and soils in this arid environment. [ABSTRACT FROM AUTHOR]

Ethanol is a clean, renewable fuel that can be produced from biomass resources in nearly every region of the United States. Today in the U.S. the majority of ethanol is produced from corn, a practice that relies on subsidies to compete economically with gasoline and diverts food supplies. Significant growth of the ethanol industry will depend on the development of new processes that convert cellulosic biomass from non-food crops and waste materials into ethanol. The purpose of this research is to compare the private and total social cost of producing ethanol using conventional methods from corn to the production of ethanol from cellulosic biomass feedstocks, and to analyze the sensitivity of the technology to key variables such as capital costs, feedstock and energy prices, and estimates of social costs. Results indicate that existing ethanol technologies hold an economic advantage due primarily to the larger capital costs and greater complexity associated with the cellulosic ethanol conversion process. However, under certain economic conditions cellulosic technology is competitive with traditional methods. [ABSTRACT FROM AUTHOR]

A dipeptidyl carboxypeptidase activity in the Dunning rat prostate tumor was characterized. This enzyme demonstrated the most prominent properties of angiotensin converting enzyme (ACE): that is, it was stimulated by NaCl and Co 2+ and was potently inhibited by captopril. The enzyme solubilized by Triton X-100 had a molecular mass of 110 kDa as determined by gel filtration chromatography. The specific activity of ACE did not change with castration, indicating that ACE activities are not controlled by androgen. The role of ACE in the prostate and its tumors is not understood, but the ability of this enzyme to hydrolyze a number of bioactive peptides suggests that it may function in controlling the molecular forms or activity of regulatory peptides. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine whether protease inhibitors were a constituent of secretions from the different lobes of the rat prostate. A reverse zymography method was used employing gelatin substrate-SDS-polyacrylamide gel electrophoresis to detect inhibitors of trypsin in secretions of the ventral, lateral, and dorsal prostate lobes of the Sprague-Dawley rat. Inhibitors of approximately 34 and 63 kDa were detected in ventral prostate secretion and of about 63 and 73 kDa were found in lateral lobe secretion. However, no inhibitor activities were detected in secretions of the dorsal lobe. The protease inhibitors of ventral prostate secretion were partially purified by preparatory isoelectric focusing and SDS-polyacrylamide gel electrophoresis. The 34-kDa (pI 5.6-6.4) inhibitor had a higher activity against trypsin, whereas the 63-kDa (pI 6.4-7.0) inhibitor was more active against chymotrypsin. The rat prostate appears to have a lobe-specific distribution of secretory serine protease inhibitors. [ABSTRACT FROM AUTHOR]

We report an efficient process for controlled fabrication of high-resolution magnetic force microscope probes using preformed magnetic nanowires. Nickel and cobalt nanowires produced by electrodeposition were directly assembled onto the tip of a commercial atomic force microscope cantilever with controlled orientation and length by dielectrophoresis. The properties of these nanowire-based probes are characterized. [ABSTRACT FROM AUTHOR]