New Insights into the Evolution of an Intervalley Prehistoric Irrigation Canal System,North Coastal Peru     

Gary Huckleberry  Frances Hayashida  Jack Johnson 《Geoarchaeology》2012,27(6):492-520

We present the results of combined AMS‐¹⁴C and single‐grain luminescence dating of pre‐Columbian irrigation canals that are part of the Racarumi Intervalley Canal System (RICS) in northern Peru. Archaeological and archival evidence suggest that the RICS was constructed during Middle Sicán (A.D. 900–1100) rule and continued to operate during Chimú and Inka conquests in the A.D. 1300s and 1400s, respectively, until finally succumbing to Spanish control of the area in the early A.D. 1500s. Detrital charcoal (AMS‐¹⁴C) and sand grains (OSL and IRSL) were collected from active, post‐abandonment, and clean out deposits in six earthen canals located within three separate alignments of the RICS. Resulting ages confirm operation during Middle Sicán, Late Sicán, Chimú, and Inka control, and possibly into the early part of the Spanish period. Placed within their hydroclimatological context, RICS canal deposits document recurrent El Niño flooding ∼A.D. 1300–1600 but indicate that damage to the system was repaired and the canals continued to operate despite periodic disruptions. This study demonstrates that single‐grain luminescence analysis conducted within a framework of geomorphology and formation processes has significant potential for detailed and accurate dating of ancient water‐control systems.  相似文献   

Child sponsorship,ordinary ethics and the geographies of charity     

Frances Rabbitts 《Geoforum》2012,43(5):926-936

Charitable donation, far from being done in a vacuum, is practised inseparably from the messy spatialities of everyday life. Drawing on literature from the geographies of care, this paper analyses the practices and experiences of giving that surround child sponsorship, a popular charitable scheme that directly links each donor with a child somewhere in the Global South. Through this, the paper argues for a more nuanced approach to the spatialities of charity. It affirms the significance of donation not just as a one-off response to a tear-jerking campaign, or as a mundane regular commitment, but also as a deeply personal engagement that draws into play multiple different aspects of people’s everyday lives and intersects with existing identity- and community-building projects. Throughout, therefore, the paper focuses specifically on the micro-geographies of donation, engaging with the messy details of everyday performances of charitable ethics and identity. To achieve this, it draws empirically on interviews with a small number of British sponsors, most of whom expressed an affiliation with the Christian faith. The paper therefore foregrounds a particular focus on the dialogic relationship between the spatialities of charity and the landscapes of faith, religion and spirituality.  相似文献   

Black gold to green gold: regional energy policy and the rehabilitation of coal in response to climate change     

Frances Drake 《Area》2009,41(1):43-54

Energy production has come under increasing scrutiny as concerns about energy security and climate change have risen. In the UK changes in government structure and privatisation of the electricity industry have led to the emergence of multi-level governance. This means that decisions on how to reduce carbon dioxide emissions from the electricity-generating sector should no longer be solely a national policy decision. Previous studies have sought to explore how renewable energy may develop under multi-level governance, but this paper pays attention to a traditional fossil fuel source, coal, which is still an important means of electricity generation. Coal is the most abundant fossil fuel and advocates argue that carbon capture and storage techniques could make coal 'clean', paving the way for a long-term, secure and low emission way to produce energy. This study focuses on the Yorkshire and Humber Region, which has had a long association with coal mining and looks at the implications of this as the region seeks to develop a climate change action plan and an energy strategy within the new regional governance structures. The paper argues that the regional networks developed to address climate change are influenced by existing social power structures and alliances. The region as a territorial structure becomes a useful device in promoting national priorities.  相似文献   

Organic matter degradation in paper sludge amendments over gold mine tailings     

Christine Cousins  Glenn H. Penner  Bruce Liu  Peter Beckett  Graeme Spiers 《Applied Geochemistry》2009

The long-term stability of paper sludge amendments as covers for reclaimed mine waste storage facilities must be assessed by the mining industry. This study examines a 6 yr old sequence of paper sludge amendments applied over wastes from historic Au mines located in Northern Ontario, Canada. As paper sludge is mostly comprised of C-rich organic compounds, elemental quantification, ¹³C cross polarization/magic angle spinning nuclear magnetic resonance (¹³C CP/MAS NMR) spectroscopy, and Fourier transform infrared (FTIR) spectroscopy were used to examine the minimal changes in the C content and speciation observed of the amendments over time. These results suggest that paper sludge covers are suitable for use in medium to long-term mining reclamation strategies.  相似文献   

Characterization of Flow Parameters Controlling Soil Vapor Extraction     

G. D. Beckett  David Huntley 《Ground water》1994,32(2):239-247

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Flare asymmetry as seen in offband Hα filtergrams     

Frances Tang 《Solar physics》1983,83(1):15-25

Narrow-band Hα filtergrams at ±1 Å and ±2 Å from the line center were used to study the asymmetry of flares. Of the 60 flares studied, 92% show red asymmetry while 5% show blue asymmetry. Typically, the filtergrams show a striking dominance of the red wing over the blue wing from onset until late in the decay phase. The difference in intensity of the flare emissions is further augmented by the extensiveness of the emission area in the brighter wing. New kernel-like emissions were often found many minutes after the flare maximum. Spatially they are displaced from the previous kernels. The late emissions show the same asymmetry as that of the earlier part of the flare.  相似文献   

PARTICLES AROUND BOXHOLE METEORITE CRATER     

Paul W. Hodge  Frances W. Wright 《Meteoritics & planetary science》1973,8(4):315-320

A sampling program of soil surrounding the Boxhole meteorite crater reveals very much smaller amounts of meteoritic material in the soil than found for other craters, such as Henbury and Canyon Diablo. Microprobe analyses of individual small particles show the presence of four spherules with Ni-Fe ratios in agreement with that for the parent meteorite.  相似文献   

Flaring arches     

Juan M. Fontenla  Zdeněk Švestka  František Fárník  Frances Y. Tang 《Solar physics》1991,134(1):145-169

We show detailed observations in X-rays, UV lines, and H of an extended arch, about 300000 km long, which developed as a consequence of a compact subflare. This subflare occurred in an included magnetic polarity of relatively low magnetic field strength (compared to that of the sunspots). The apparition of this big arch was preceded by that of a smaller arch, about 30000 km long, which masked the polarity inversion line filament in the early phase of the subflare. The big arch which developed later, around the time of the main X-ray and UV spike of the subflare, connected the included polarity and the main leading sunspot of the region, and became fully developed in a few minutes. The fact that both arches were simultaneously observed in all spectral domains as well as their fine structure in H can only be explained by considering the arch as composed of several unresolved portions of material having widely different temperatures. The H observations can be interpreted as showing the appearance of this cool material as a result of condensation, but a more appealing interpretation is that there was almost simultaneous ejection of superhot (10⁷ K), hot (10⁶ K), mild (10⁵ K), and cool (10⁴ K) material from the subflare site along previously existing magnetic tubes of much lower density. The termination of the subflare was marked by a rather hard X-ray and UV spike which appeared to originate in a different structure than that of the main spike. The material in the arch gradually cooled and drained down after the end of the subflare.Member of Carrera del Investigador, CONICET, Argentina.  相似文献   

X-ray bright surges   总被引：1，自引：0，他引：1  

Zdeněk Švestka  František Fárník  Frances Tang 《Solar physics》1990,127(1):149-163

We present evidence of X-ray emission from surges that are bright in H. These surges have many features common to flaring arches of Martin and vestka (1988); the basic difference between the two is that in flaring arches cold and hot plasma are injected into clearly defined closed magnetic loops, while in the surges the injection goes into large-scale magnetic field structures of which the second footpoint is usually unknown. Because of the steep density gradient in such large-scale structures, the X-ray visibility of bright surges is limited to a few tens of seconds only. A series of repetitive surges, some of them bright and emitting X-rays, occurred on 8 July, 1980 from footpoints of two large-scale coronal structures, which might have been the legs of an enormous arch at least 600 Mm long.  相似文献   

Phytoplankton assemblages in the CoOP-WEST coastal upwelling area     

Adria M. Lassiter  Frances P. Wilkerson  Richard C. Dugdale  Victoria E. Hogue 《Deep Sea Research Part II: Topical Studies in Oceanography》2006,53(25-26):3063

Elevated levels of phytoplankton were observed at the Northern California coastal upwelling ecosystem studied as part of the CoOP-WEST project during monthly summer surveys in 2000, 2001 and 2002. The high concentrations of chlorophyll were made up mostly of larger cells; the phytoplankton communities that resulted were dominated by centric diatoms. The highest chlorophyll a concentrations were observed when large diatoms or small colony-forming species dominated the assemblages. In contrast, when smaller nano-flagellates and picoplankton were dominant, total chlorophyll a concentrations were over four or five-fold lower than when diatoms were prevalent, illustrating the importance of large diatoms to total phytoplankton biomass. Each year, when chlorophyll concentrations were greatest, Chaetoceros species created a Chaetoceros-dominated system. A few other genera contributed to the upwelling diatom community, mostly the centric diatoms Asterionella, Thalassiosira, Rhizosolenia (including Guinardia and Proboscia), and the pennate Nitzschia. These diatoms have been described in other coastal upwelling ecosystems, and at this study site form a functional group that are apparently well adapted to the high-nutrient, turbulent conditions that are typical of these coastal regions.  相似文献