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101.
“Giving voice” to participants has been an important element of qualitative feminist research projects in geography. In this article, I explore scholarship that has questioned qualitative research's reliance on voice, arguing that implicit connections between voice, authenticity, and empowerment are beginning to be unpacked, particularly by scholars engaged in anticolonial work. I draw on anticolonial scholarship to build on and extend feminist debates centered on voice and participation. Feminist attention to voice must be situated within the colonial frameworks and histories of social science research. Scholarship focused on ongoing settler colonial relationships highlights methods both for cautiously proceeding with and consciously refusing incorporating voice within qualitative research. I draw on anticolonial approaches to frame research decisions, voice, and the ethical and methodological dilemmas of its use.  相似文献   
102.
Seasonal variations in coccolithophore abundance, chlorophyll, nutrients and production of particulate organic and inorganic carbon (POC and PIC) were determined along a coastal to oceanic east-west transect (Line P) culminating at Ocean Station Papa in the northeastern subarctic Pacific between 1998 and 2000. Offshore stations generally exhibited low seasonality in chlorophyll concentrations, with moderate seasonality in POC production. Near shelf stations showed a similar pattern to offshore stations, but were also characterized by sporadic events of higher POC productivity. During the 1998 El Niño, June was characterized by low chlorophyll and POC productivity along the transect, presumably as a result of depleted surface nitrate. In contrast, during the 1999 La Niña, and in 2000, higher POC productivity and surface nitrate occurred along the transect in June. Chlorophyll and POC productivity were similar in late summer in all 3 years. The coccolithophore population was usually numerically dominated by Emiliania huxleyi, particularly in June. Along the transect, abundance of coccolithophores was much higher in June during the 1998 El Niño (mean of 221 cells ml−1) than in the 1999 La Niña (mean of 40 cells ml−1), with their abundance in late summers of both years being very low. Abundances were even higher along the transect in June and the late summer of 2000 with sporadic ‘blooms’ of >1000 cells ml−1 at some stations (cruise averages 395 and 552 cell ml−1, respectively). Production rates of PIC did not consistently correlate with areas of high coccolithophore abundance. PIC production was high (100-250 mg C m−2 d−1) along the transect during June 1998, and low (1-40 mg C m−2 d−1) during both winters, June 1999 and during late summers of 1998 and 1999. The year 2000 was more complicated, with high rates of PIC production accompanying high abundance of coccolithophores in late summer, but lower rates of PIC production accompanying high coccolithophore numbers in June. Our data suggest that the abundance of coccolithophores and the production rates of PIC in the subarctic are higher than previously thought. Occasional PIC:POC production ratios of 1 or greater in 1998 and 2000 suggest that coccolithophores in this region could have a significant impact on the efficiency of the biological carbon pump.  相似文献   
103.
Two suites of regionally metamorphosed semi-pelitic schists were studied in order to investigate the paragenesis of low temperature plagioclase, from which something may be inferred as to the nature of the peristerite solvus at the temperatures and pressures of formation of these rocks: one from the Gile Mountain Formation in the Hanover and Mt. Cube quadrangles, eastern Vermont, U.S.A.; the other from the Alpine schists along the Haast River, South Westland, New Zealand. Plagioclase, muscovite, biotite, chlorite, carbonate, and garnet compositions were determined with an ARL EMX electron probe microanalyzer. The variation in plagioclase composition with increasing grade in the Vermont schists suggests that the peristerite solvus is asymmetrical with a near vertical albite-rich side and a sloping oligoclase-rich side. The top of the solvus appears to lie slightly above the temperature expressed by the almandine isograd in these schists. The compositions of the coexisting albite and oligoclase in the New Zealand rocks suggest a lower geothermal gradient than in Vermont, creating a different pattern of variation in plagioclase composition. Distribution diagrams of Mg, Ti, and AlIV for muscovite-biotite and chlorite-biotite pairs in both suites of rocks support the hypothesis that the plagioclase relations observed represent equilibrium.  相似文献   
104.
Detailed acoustic surveys of benthic sediments were conducted in July 1995 and September 1998 in the vicinity of Humboldt Bay, California. During these surveys, a band of enhanced acoustic backscatter was observed offshore from the bay entrance, approximately parallel to the isobaths, in water depths ranging from 16-24 m. In order to assess the cause of the increase in backscatter levels, a more comprehensive study was conducted in August and September 1999 using 100 kHz side-scan sonar, bottom grab sampling and underwater video recording. New observations indicated that a dense population of sand dollars ( Dendraster excentricus ) coincided with the enhanced backscatter band. Compared to the two previous acoustic studies, the central section of the band expanded westward by 180 m and the southern section of the band shifted eastward by 160 m, possibly resulting from a change in the biological or physical factors which influence the location and breadth of sand dollars. The relationship between high sand dollar abundance and enhanced acoustic backscatter was further verified in the nearshore region off Samoa Beach California, where a dense, banded population of sand dollars was previously observed. Video footage confirmed the presence of a band of sand dollars, also nominally parallel to the isobaths, in water depths of 8-15 m. A band of enhanced backscatter coincided with the dense sand dollar population. The identification of dense aggregations of sand dollars through enhanced acoustic backscatter could lead to the use of acoustic techniques to study sand dollar distributions and abundance.  相似文献   
105.
Vertical profiles of temperature and salinity have been measured for 50 years along Line P between the North American west coast and mid Gulf of Alaska. These measurements extend 1425 km into the gulf at 13 or more sampling stations. The 10-50-m deep layer of Line P increased in temperature by 0.9 °C from 1958 to 2005, but is significant only at the 90% level due to large interannual variability. Most of this increase in temperature accompanies the 1977 shift in wind patterns. Temperature changes at 100-150 m and salinity changes in both layers are not statistically significant. Much of the variance in temperature is in the upper 50 m of Line P, and temperature changes tend to be uniform along Line P except for waters on the continental margin. Salinity changes are dominated by variability in the halocline between 100 and 150 m depth and are less uniform along Line P. Largest oscillations in temperature and salinity are between 1993 and 2003. These events can be understood by considering changes in eastward wind speed and wind patterns that are revealed in the first two modes of the Pacific Decadal Oscillation. Changes in these patterns are indicators for both Ekman surface forcing (Surface ocean currents flow to the right of the wind direction) and Ekman pumping (Surface waters diverge away from regions of positive wind stress curl, leading to upwelling of colder saltier water). Changes in temperature along the nearshore part of Line P suggest Ekman surface forcing is the stronger of the two processes in the upper layer. The change in salinity anomalies in the halocline along the seaward end of Line P, following the wind shift in 1977, is in agreement with enhanced upwelling caused by stronger Ekman pumping in this region.  相似文献   
106.
The purpose of the article is to examine the ways in which regional geography textbooks are used in elementary education, using north-west Bohemia as a case study. The authors analysed 18 textbooks published since the beginning of the 20th century, in two steps: (1) the construction of geographical names frequency maps indicating which parts of the case region are accentuated or suppressed in individual textbooks, and (2) a qualitative analysis of the textbooks’ content. The study revealed that a complex image of north-west Bohemia in interwar period in Czechoslovakia and in the period of accession to the European Union is presented in the textbooks. The textbooks published during communist era are imbued with the adoration of local industries, whereas those published later, in the period of political and socio-economic transformation, accentuate the risks of excessive environmental exploitation. At any time since the beginning of the 20th century, the places and regions that represent the values preferred by the governing ideology are emphasized within the studied textbooks. Thus, the geography textbooks, that reflect the society-wide discourse, disseminate not only knowledge but also dominant values. In this way, a desired image of reality is created that legitimates the aims and stances of those in power.  相似文献   
107.
The stable isotopic (2H/1H and 18O/16O) composition of precipitation has been used for a variety of hydrological and paleoclimate studies, a starting point for which is the behaviour of stable isotopes in modern precipitation. To this end, daily precipitation samples were collected over a 7‐year period (2008–2014) at a semi‐arid site located at the Macquarie Marshes, New South Wales (Australia). The samples were analysed for stable isotope composition, and factors affecting the isotopic variability were investigated. The best correlation between δ 18O of precipitation was with local surface relative humidity. The reduced major axis precipitation weighted local meteoric water line was δ 2H = 7.20 δ 18O + 9.1. The lower slope and intercept (when compared with the Global Meteoric Water Line) are typical for a warm dry climate, where subcloud evaporation of raindrops is experienced. A previously published model to estimate the degree of subcloud evaporation and the subsequent isotopic modification of raindrops was enhanced to include the vertical temperature and humidity profile. The modelled results for raindrops of 1.0 mm radius showed that on average, the measured D‐excess (=δ 2H ? 8 δ 18O) was 19.8‰ lower than that at the base of the cloud, and 18% of the moisture was evaporated before ground level (smaller effects were modelled for larger raindrops). After estimating the isotopic signature at the base of the cloud, a number of data points still plotted below the global meteoric water line, suggesting that some of the moisture was sourced from previously evaporated water. Back trajectory analysis estimated that 38% of the moisture was sourced over land. Precipitation samples for which a larger proportion of the moisture was sourced over land were 18O and 2H‐enriched in comparison to samples for which the majority of the moisture was sourced over the ocean. The most common weather systems resulting in precipitation were inland trough systems; however, only East Coast Lows contributed to a significant difference in the isotopic values. Copyright © 2016 Australian Nuclear Science and Technology Organisation. Hydrological Processes. © 2016 John Wiley & Sons, Ltd.  相似文献   
108.
Thirty‐eight dated packrat middens were collected from upper desert (930–1357 m) elevations within Joshua Tree National Park near the ecotone between the Mojave Desert and Colorado Desert, providing a 30 ka record of vegetation change with remarkably even coverage for the last 15 ka. This record indicates that vegetation was relatively stable, which may reflect the lack of invasion by extralocal species during the late glacial and the early establishment and persistence of many desert scrub elements. Many of the species found in the modern vegetation assemblages were present by the early Holocene, as indicated by increasing Sørenson's Similarity Index values. C4 grasses and summer‐flowering annuals arrived later at Joshua Tree National Park in the early Holocene, suggesting a delayed onset of warm‐season monsoonal precipitation compared to other Sonoran Desert and Chihuahuan Desert localities to the east, where summer rains and C4 grasses persisted through the last glacial–interglacial cycle. This would suggest that contemporary flow of monsoonal moisture into eastern California is secondary to the core processes of the North American Monsoon, which remained intact throughout the late Quaternary. In the Holocene, northward displacement of the jet stream, in both summer and winter, allowed migration of the subtropical ridge as far north as southern Idaho and the advection of monsoonal moisture both westward into eastern California and northward into the southern Great Basin and Colorado Plateau. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
109.
Abstract

We develop a wind‐driven depth‐averaged model of the circulation on the continental shelf around the Queen Charlotte Islands. The model captures a major feature of the winter current‐meter observations: a flow in Moresby Trough against the direction of the prevailing winds. Moresby Trough is a steep submarine canyon cutting across the shelf from the Pacific Ocean to the mainland. The flow patterns revealed by simulated drifters lead to four generalizations about the depth‐averaged, wind‐driven flow: (1) the flow is subject to strong topographic steering, (2) the exchange between Queen Charlotte Sound and the Pacific Ocean is limited to small regions near Cape St James and Cape Scott, (3) the exchange between Queen Charlotte Sound and Hecate Strait is controlled by Moresby Trough, and (4) the observed outflows past Cape St James are not explained by the dynamics of this model.  相似文献   
110.
Reducing greenhouse gas emissions from deforestation and forest degradation (REDD) is likely to be central to a post-Kyoto climate change mitigation agreement. As such, identifying conditions and factors that will shape the success or failure of a reduced deforestation scheme will provide important insights for policy planning. Given that protected areas (PAs) are a cornerstone in forest conservation, we draw on interviews and secondary data to analyze the effects of available PA resources, governance ability, the level of community involvement, and provincial deforestation rates on land-cover change in nine PAs in Panama. Our results illustrate that coupling surveillance measures with greater funding and strong governance are paramount to reducing deforestation. Alone, however, these factors are insufficient for forest protection. We argue that conservation approaches that complement effective surveillance with community participation and equitable benefit sharing will address the wider issues of leakage and permanence.  相似文献   
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