WorldWideScience

Sample records for great american desert

  1. Condition-dependent clutch desertion in Great Tit (Parus major) females subjected to human disturbance

    OpenAIRE

    2011-01-01

    Abstract Nest desertion behaviour in relation to body condition and timing of breeding was studied in Great Tit (Parus major) females during two breeding seasons. Desertion, most likely unintentionally provoked by catching females during the incubation period, occurred at a very high rate with 41.2 and 25.6% of deserted first clutches in the two study years. The association between desertion probability, body condition (index calculated as residuals from the regression of body mass...

  2. Evaluation of great deserts of the world for perpetual radiowaste storage

    International Nuclear Information System (INIS)

    Libby, L.M.; Wurtele, M.G.; Whipple, C.G.

    1982-01-01

    Desert sites with a history of seismic stability were studied for storage of radioactive wastes because of the attractive meteorology, proven longterm geological stability, and distance from human population centers. Specific deserts were to be representative of various kinds of world deserts, if substantial information about each desert was available, to examine with respect to transporting, handling, storing, and cooling the radioactive waste, and the site suitability as to geological conditions, water availability, alternative land use, airborne emissions of heat, accidental radioactive emission, and possible socioeonomic impacts. No significant technical obstacles to the use of the world deserts as sites for a retrievable storage facility for 500 years were found. However, given the relatively low level of effort that was allocated between the many technical issues listed above, this study is neither a full risk assessment nor a full environmental impact analysis of such a facility. Assessments for siting the facility were made for five deserts, chosen to be representative of Old World, New World, Australian, interior, coastal, foggy, hot and cold: the Nullarbor Plain of Australia, the Namib in Africa, the Great Basin of the United States represented by the Nevada Test Site, the North Slope of Alaska and Canada, and the Egyptian desert

  3. The water economy of South American desert rodents: from integrative to molecular physiological ecology.

    Science.gov (United States)

    Bozinovic, Francisco; Gallardo, Pedro

    2006-01-01

    Rodents from arid and semi-arid habitats live under conditions where the spatial and temporal availability of free water is limited, or scarce, thus forcing these rodents to deal with the problem of water conservation. The response of rodents to unproductive desert environments and water deficits has been intensively investigated in many deserts of the world. However, current understanding of the cellular, systemic and organismal physiology of water economy relies heavily on short-term, laboratory-oriented experiments, which usually focus on responses at isolated levels of biological organization. In addition, studies in small South American mammals are scarce. Indeed xeric habitats have existed in South America for a long time and it is intriguing why present day South American desert rodents do not show the wide array of adaptive traits to desert life observed for rodents on other continents. Several authors have pointed out that South American desert rodents lack physiological and energetic specialization for energy and water conservation, hypothesizing that their success is based more on behavioral and ecological strategies. We review phenotypic flexibility and physiological diversity in water flux rate, urine osmolality, and expression of water channels in South American desert-dwelling rodents. As far as we know, this is the first review of integrative studies at cellular, systemic and organismal levels. Our main conclusion is that South American desert rodents possess structural as well as physiological systems for water conservation, which are as remarkable as those found in "classical" rodents inhabiting other desert areas of the world.

  4. The Last Great American Picture Show

    NARCIS (Netherlands)

    Elsaesser, Thomas; King, Noel; Horwath, Alexander

    2004-01-01

    The Last Great American Picture Show brings together essays by scholars and writers who chart the changing evaluations of the American cinema of the 1970s, sometimes referred to as the decade of the lost generation, but now more and more recognized as the first New Hollywood, without which the

  5. Deserts

    Science.gov (United States)

    Belnap, Jayne; Webb, Robert H.; Esque, Todd; Brooks, Matthew L.; DeFalco, Lesley; MacMahon, James A.

    2016-01-01

    The deserts of California (Lead photo, Fig. 1) occupy approximately 38% of California’s landscape (Table 1) and consist of three distinct deserts: the Great Basin Desert, Mojave Desert, and Colorado Desert, the latter of which is a subdivision of the Sonoran Desert (Brown and Lowe 1980). The wide range of climates and geology found within each of these deserts result in very different vegetative communities and ecosystem processes and therefore different ecosystem services. In deserts, extreme conditions such as very high and low temperatures and very low rainfall result in abiotic factors (climate, geology, geomorphology, and soils) controlling the composition and function of ecosystems, including plant and animal distributions. This is in contrast to wetter and milder temperatures found in other ecosystems, where biotic interactions are the dominant driving force. However, despite the harsh conditions in deserts, they are home to a surprisingly large number of plants and animals. Deserts are also places where organisms display a wide array of adaptations to the extremes they encounter, providing some of the best examples of Darwinian selection (MacMahon and Wagner 1985, Ward 2009). Humans have utilized these regions for thousands of years, despite the relatively low productivity and harsh climates of these landscapes. Unlike much of California, most of these desert lands have received little high-intensity use since European settlement, leaving large areas relatively undisturbed. Desert landscapes are being altered, however, by the introduction of fire following the recent invasion of Mediterranean annual grasses. As most native plants are not fire-adapted, they Many do not recover, whereas the non-native grasses flourish. Because desert lands are slow to recover from disturbances, energy exploration and development, recreational use, and urban development will alter these landscapes for many years to come. This chapter provides a brief description of where the

  6. Foraging behavior of heritage versus recently introduced herbivores on desert landscapes of the American Southwest

    Science.gov (United States)

    Since the 1800s managed grasslands and shrublands of the arid American Southwest have been grazed predominantly by cattle originally bred for temperate climates in northern Europe. A heritage breed, the criollo cattle, has survived in northern Mexico for more than 400 years under desert-like conditi...

  7. Plant responses to an edaphic gradient across an active sand dune/desert boundary in the great basin desert.

    NARCIS (Netherlands)

    Rosenthal, D.M.; Ludwig, F.; Donovan, L.A.

    2005-01-01

    In arid ecosystems, variation in precipitation causes broad-scale spatial heterogeneity in soil moisture, but differences in soil texture, development, and plant cover can also create substantial local soil moisture heterogeneity. The boundary between inland desert sand dunes and adjacent desert

  8. Gopherus agassizii: Desert tortoise

    Science.gov (United States)

    Berry, Kristen H.; Swingland, Ian Richard; Klemens, Michael W.

    1989-01-01

    The desert tortoise is one of four allopatric North American tortoises. It occurs in the Mojave and Sonoran deserts of the southwestern United States and Mexico.Auffenberg (1976) divided the genus Gopherus (consisting of four species, G. agassizi, G. berlandieri, G.flavomarginatus, and G. polyphemus) in two osteological groups. Bramble (1982), using morphological and palaeontological data, divided the genus Gopherus into two separate complexes, each with two species. He established a new genus, Scaptochelys, for agassizi and berlandieri, retaining Gopherus for polyphemus and flavomarginatus. Bour and Dubois (1984) noted that Xerobates Agassiz had priority over Scaptochelys Bramble. Using mitochondrial DNA (mtDNA), Lamb et al. (1989) evaluated the evolutionary relationships of the North American tortoises, particularly the desert tortoise. They concluded that the mtDNA analysis provides strong support for generic recognition of the two distinct species groups described by Bramble (1982).Until a few decades ago, the desert tortoise was widespread at lower elevations throughout the Mojave and Sonoran deserts of the U.S.A. In the northern and western parts of the geographic range, large and relatively homogeneous populations with densities exceeding 1,000/sq km extended throughout parts of California, and probably into Nevada and Utah. In terms of biomass, the tortoise played an important role in the ecosystems. In most areas, numbers have declined dramatically and the extent of populations has been reduced. Most populations are now isolated and low in numbers. Conservation of the desert tortoise is a highly visible and political issue in the U.S.A., but not in Mexico.

  9. Great Gatsby-the Disillusionment of American Dream

    Institute of Scientific and Technical Information of China (English)

    赵玮

    2005-01-01

    American Dream is a mystery. It makes a lot of Americans prosperous, but also ruins some of them. In The Great Gatsby by F. Scott Fitzgerald, Gatsby is just such a character created to describe the disillusionment of the American Dream. Yet, his doom of failure results from his illusion actually. In this essay, we shall see how the American dream of Gatsby comes from illusion to disillusionment step by step. Besides, what kind of person Gatsby is and what kind of love Gatsby and his ideal love "Daisy" has are depicted in this essay to reveal the doom of Gatsby's dream. And a general understanding of the Jazz Age, the specific era Gatsby is set in, of the original sense of American Dream and also of the conflicts between two extreme classes in the face of the challenge of American Dream will make us clearer of how Gatsby - the tragic hero - met his fate.

  10. The Riparianness of a Desert Herpetofauna

    Science.gov (United States)

    Charles H. Lowe

    1989-01-01

    Within the Mojave, Sonoran, and Chihuahuan Desert subdivisions of the North American Desert in the U.S., more than half of 143 total amphibian and reptilian species perform as riparian and/or wetland taxa. For the reptiles, but not the amphibians, there is a significant inverse relationship between riparianness (obligate through preferential and facultative to...

  11. The Disillusion of American Dream-Essay On“The Great Gatsby”

    Institute of Scientific and Technical Information of China (English)

    赵洁

    2013-01-01

    “The Great Gatsby”, a fiction by Fitzgerald, is about the failure of the American dream. For the protagonist Gatsby, He is the true heir to American dream. He devotes his whole life to pursues his dream of romantic success without ever understand-ing that it has escaped him. Finally, he dies in his pursuit. His failure symbolizes the disillusion of American dream.

  12. American undergraduate students' value development during the Great Recession.

    Science.gov (United States)

    Park, Heejung; Twenge, Jean M; Greenfield, Patricia M

    2017-02-01

    The Great Recession's influence on American undergraduate students' values was examined, testing Greenfield's and Kasser's theories concerning value development during economic downturns. Study 1 utilised aggregate-level data to investigate (a) population-level value changes between the pre-recession (2004-2006: n = 824,603) and recession freshman cohort (2008-2010: n = 662,262) and (b) overall associations of population-level values with national economic climates over long-term periods by correlating unemployment rates and concurrent aggregate-level values across 1966-2015 (n = 10 million). Study 2 examined individual-level longitudinal value development from freshman to senior year, and whether the developmental trajectories differed between those who completed undergraduate education before the Great Recession (freshmen in 2002, n = 12,792) versus those who encountered the Great Recession during undergraduate years (freshmen in 2006, n = 13,358). Results suggest American undergraduate students' increased communitarianism (supporting Greenfield) and materialism (supporting Kasser) during the Great Recession. The recession also appears to have slowed university students' development of positive self-views. Results contribute to the limited literature on the Great Recession's influence on young people's values. They also offer theoretical and practical implications, as values of this privileged group of young adults are important shapers of societal values, decisions, and policies. © 2016 International Union of Psychological Science.

  13. Geology, selected geophysics, and hydrogeology of the White River and parts of the Great Salt Lake Desert regional groundwater flow systems, Utah and Nevada

    Science.gov (United States)

    Rowley, Peter D.; Dixon, Gary L.; Watrus , James M.; Burns, Andrews G.; Mankinen, Edward A.; McKee, Edwin H.; Pari, Keith T.; Ekren, E. Bartlett; Patrick , William G.; Comer, John B.; Inkenbrandt, Paul C.; Krahulec, K.A.; Pinnell, Michael L.

    2016-01-01

    The east-central Great Basin near the Utah-Nevada border contains two great groundwater flow systems. The first, the White River regional groundwater flow system, consists of a string of hydraulically connected hydrographic basins in Nevada spanning about 270 miles from north to south. The northernmost basin is Long Valley and the southernmost basin is the Black Mountain area, a valley bordering the Colorado River. The general regional groundwater flow direction is north to south. The second flow system, the Great Salt Lake Desert regional groundwater flow system, consists of hydrographic basins that straddle

  14. Evidence of aqueous secondary organic aerosol formation from biogenic emissions in the North American Sonoran Desert.

    Science.gov (United States)

    Youn, Jong-Sang; Wang, Zhen; Wonaschütz, Anna; Arellano, Avelino; Betterton, Eric A; Sorooshian, Armin

    2013-07-16

    This study examines the role of aqueous secondary organic aerosol formation in the North American Sonoran Desert as a result of intense solar radiation, enhanced moisture, and biogenic volatile organic compounds (BVOCs). The ratio of water-soluble organic carbon (WSOC) to organic carbon (OC) nearly doubles during the monsoon season relative to other seasons of the year. When normalized by mixing height, the WSOC enhancement during monsoon months relative to preceding dry months (May-June) exceeds that of sulfate by nearly a factor of 10. WSOC:OC and WSOC are most strongly correlated with moisture parameters, temperature, and concentrations of O 3 and BVOCs. No positive relationship was identified between WSOC or WSOC:OC and anthropogenic tracers such as CO over a full year. This study points at the need for further work to understand the effect of BVOCs and moisture in altering aerosol properties in understudied desert regions.

  15. The Great Migration and African-American Genomic Diversity.

    Directory of Open Access Journals (Sweden)

    Soheil Baharian

    2016-05-01

    Full Text Available We present a comprehensive assessment of genomic diversity in the African-American population by studying three genotyped cohorts comprising 3,726 African-Americans from across the United States that provide a representative description of the population across all US states and socioeconomic status. An estimated 82.1% of ancestors to African-Americans lived in Africa prior to the advent of transatlantic travel, 16.7% in Europe, and 1.2% in the Americas, with increased African ancestry in the southern United States compared to the North and West. Combining demographic models of ancestry and those of relatedness suggests that admixture occurred predominantly in the South prior to the Civil War and that ancestry-biased migration is responsible for regional differences in ancestry. We find that recent migrations also caused a strong increase in genetic relatedness among geographically distant African-Americans. Long-range relatedness among African-Americans and between African-Americans and European-Americans thus track north- and west-bound migration routes followed during the Great Migration of the twentieth century. By contrast, short-range relatedness patterns suggest comparable mobility of ∼15-16km per generation for African-Americans and European-Americans, as estimated using a novel analytical model of isolation-by-distance.

  16. Chemical constituents of Cenchrus ciliaris L. from the Cholistan desert, Pakistan

    OpenAIRE

    Ashraf Muhammad Aqeel; Mahmood Karamat; Yusoff Ismail; Qureshi Ahmad Kaleem

    2013-01-01

    The Cholistan Desert is an extension of the Great Indian Desert, covering an area of 26,330 km2. The desert can be divided into two main geomorphic regions: the northern region, known as Lesser Cholistan, constituting the desert margin and consisting of a series of saline alluvial flats alternating with low sand ridges/dunes; and the southern region, known as Greater Cholistan, a wind-resorted sandy desert comprised of a number of old Hakra River terraces w...

  17. Southern Peru desert shattered by the great 2001 earthquake: Implications for paleoseismic and paleo-El Niño–Southern Oscillation records

    OpenAIRE

    Keefer, David K.; Moseley, Michael E.

    2004-01-01

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2–8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term “shattered landscape” to describe th...

  18. Southern Peru desert shattered by the great 2001 earthquake: implications for paleoseismic and paleo-El Nino-Southern Oscillation records.

    Science.gov (United States)

    Keefer, David K; Moseley, Michael E

    2004-07-27

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2-8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term "shattered landscape" to describe the severity of these effects. Long-term consequences of this landscape shattering are inferred to include increased runoff and sediment transport during postearthquake rainstorms. This inference was confirmed during the first minor postearthquake rainstorm there, which occurred in June and July of 2002. Greater amounts of rainfall in this desert region have historically been associated with El Niño events. Previous studies of an unusual paleoflood deposit in this region have concluded that it is the product of El Niño-generated precipitation falling on seismically disturbed landscapes. The effects of the 2001 earthquake and 2002 rainstorm support that conclusion.

  19. A potential predator-prey interaction of an American badger and an Agassiz's desert tortoise with a review of badger predation on turtles

    Science.gov (United States)

    Smith, Amanda L.; Puffer, Shellie R.; Lovich, Jeffrey E.; Tennant, Laura A.; Arundel, Terry; Vamstad, Michael S.; Brundige, Kathleen D.

    2016-01-01

    The federally threatened Agassiz’s desert tortoise (Gopherus agassizii) was listed under the U.S. Endangered Species Act in 1990, but thus far, recovery efforts have been unsuccessful (U.S. Fish and Wildlife Service [USFWS] 2015). Predation has been identified as a contributing factor to declining G. agassizii populations range-wide (e.g., Esque et al. 2010, Lovich et al. 2014). Understanding and managing for predator-prey dynamics is thus an important part of the recovery and conservation of this threatened species (USFWS 2011). Desert tortoises have a host of predators at all stages of their life cycle. Over 20 species of birds, mammals, and reptiles have been recorded as known or suspected predators (Woodbury and Hardy 1948, Luckenbach 1982, Ernst and Lovich 2009). American badgers (Taxidea taxus, family: Mustelidae) are confirmed excavators of desert tortoise nests (Turner and Berry 1984). They are also suspected predators of adult desert tortoises, a possibility which has been presented in some studies but without empirical verification (Luckenbach 1982, Turner and Berry 1984). Active mostly at night, badgers are solitary, secretive predators (Lindzey 1978, 1982; Armitage 2004) that are extremely difficult to observe in predatory encounters. Recently, strong circumstantial evidence presented by Emblidge et al. (2015) suggests that badgers do prey on adult Agassiz’s desert tortoises based on observations of more than two dozen dead tortoises in the Western Mojave Desert of California. In this note, we present another case of potential badger predation on a large adult desert tortoise in the Sonoran Desert of California. Collectively, these recent two cases potentially indicate that badger predation may be more common and widespread than previously thought. In addition, we review the worldwide literature of badger predation on turtles in general and summarize reported badger observations in Joshua Tree National Park, where our observation occurred, over a

  20. An Analysis of Disillusionment of American Dream in The Great Gatsby

    Institute of Scientific and Technical Information of China (English)

    李成烨

    2015-01-01

    American dream has always been a hot topic in the study and research of the American literature.And this topic has been researched deeply by many scholars and those who are interested in the field of literature.But the study or analysis of the disillusionment of American dream keeps updating from different angles by people from different fields,for the success of American dream isn’t easy to achieve by people.While this paper is going to illustrate the disillusionment of American dream of Gatsby and explain the reason that Gatsby failed but made him Great.

  1. A long-term vegetation history of the Mojave-Colorado Desert ecotone at Joshua Tree National Park

    Science.gov (United States)

    Holmgren, Camille A.; Betancourt, Julio L.; Rylander, Kate A.

    2010-01-01

    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.

  2. In vitro germination of desert rose varieties(

    OpenAIRE

    Tatiane Lemos Varella; Gizelly Mendes Silva; Kaliane Zaira Camacho Maximiliano da Cruz; Andréia Izabel Mikovski; Josué Ribeiro da Silva Nunes; Ilio Fealho Carvalho; Maurecilne Lemes Silva

    2015-01-01

    The drought stress resistance is a characteristic of the desert rose and its estimable beauty flowers, which gave it great relevance in the ornamental market. However, the desert rose production and germination is hampered by possible sterility of their male and female flowers and frequent problems in pollination, so the tissue culture is a promising alternative to the propagation of these plants. This study aimed to evaluate the effect of gibberellic acid on four commercial varieties of dese...

  3. The Great American Recession and forgone healthcare: Do widened disparities between African-Americans and Whites remain?

    Directory of Open Access Journals (Sweden)

    Jasmine L Travers

    Full Text Available During the Great Recession in America, African-Americans opted to forgo healthcare more than other racial/ethnic groups. It is not understood whether disparities in forgone care returned to pre-recession levels. Understanding healthcare utilization patterns is important for informing subsequent efforts to decrease healthcare disparities. Therefore, we examined changes in racial disparities in forgone care before, during, and after the Great Recession.Data were pooled from the 2006-2013 National Health Interview Survey. Forgone medical, mental, and prescription care due to affordability were assessed among African-Americans and Whites. Time periods were classified as: pre-recession (May 2006-November 2007, early recession (December 2007-November 2008, late recession (December 2008-May 2010 and post-recession (June 2010-December 2013. Multivariable logistic regressions of race, interacted with time periods, were used to identify disparities in forgone care controlling for other demographics, health insurance coverage, and having a usual place for medical care across time periods. Adjusted Wald tests were performed to identify significant changes in disparities across time periods.The sample consisted of 110,746 adults. African-Americans were more likely to forgo medical care during the post- recession compared to Whites (OR = 1.16, CI = 1.06, 1.26; changes in foregone medical care disparities were significant in that they increased in the post-recession period compared to the pre-recession (OR = 1.17, CI = 1.08, 1.28 and OR = 0.89, CI = 0.77, 1.04, respectively, adjusted Wald Test p-value < 0.01. No changes in disparities were seen in prescription and mental forgone care.A persistent increase in forgone medical care disparities existed among African-Americans compared to Whites post-Great Recession and may be a result of outstanding issues related to healthcare access, cost, and quality. While health insurance is an important component of access

  4. Southern Peru desert shattered by the great 2001 earthquake: Implications for paleoseismic and paleo-El Niño–Southern Oscillation records

    Science.gov (United States)

    Keefer, David K.; Moseley, Michael E.

    2004-01-01

    In the desert region around the coastal city of Ilo, the great southern Peru earthquake of June 23, 2001 (8.2–8.4 moment magnitude), produced intense and widespread ground-failure effects. These effects included abundant landslides, pervasive ground cracking, microfracturing of surficial hillslope materials, collapse of drainage banks over long stretches, widening of hillside rills, and lengthening of first-order tributary channels. We have coined the term “shattered landscape” to describe the severity of these effects. Long-term consequences of this landscape shattering are inferred to include increased runoff and sediment transport during postearthquake rainstorms. This inference was confirmed during the first minor postearthquake rainstorm there, which occurred in June and July of 2002. Greater amounts of rainfall in this desert region have historically been associated with El Niño events. Previous studies of an unusual paleoflood deposit in this region have concluded that it is the product of El Niño-generated precipitation falling on seismically disturbed landscapes. The effects of the 2001 earthquake and 2002 rainstorm support that conclusion. PMID:15263069

  5. Late Quaternary history of the Atacama Desert

    Science.gov (United States)

    Latorre, Claudio; Betancourt, Julio L.; Rech, Jason A.; Quade, Jay; Holmgren, Camille; Placzek, Christa; Maldonado, Antonio; Vuille, Mathias; Rylander, Kate A.; Smith, Mike; Hesse, Paul

    2005-01-01

    Of the major subtropical deserts found in the Southern Hemisphere, the Atacama Desert is the driest. Throughout the Quaternary, the most pervasive climatic influence on the desert has been millennial-scale changes in the frequency and seasonality of the scant rainfall, and associated shifts in plant and animal distributions with elevation along the eastern margin of the desert. Over the past six years, we have mapped modern vegetation gradients and developed a number of palaeoenvironmental records, including vegetation histories from fossil rodent middens, groundwater levels from wetland (spring) deposits, and lake levels from shoreline evidence, along a 1200-kilometre transect (16–26°S) in the Atacama Desert. A strength of this palaeoclimate transect has been the ability to apply the same methodologies across broad elevational, latitudinal, climatic, vegetation and hydrological gradients. We are using this transect to reconstruct the histories of key components of the South American tropical (summer) and extratropical (winter) rainfall belts, precisely at those elevations where average annual rainfall wanes to zero. The focus has been on the transition from sparse, shrubby vegetation (known as the prepuna) into absolute desert, an expansive hyperarid terrain that extends from just above the coastal fog zone (approximately 800 metres) to more than 3500 metres in the most arid sectors in the southern Atacama.

  6. Using Stellarium to cyber-observe the Great American Eclipse

    Science.gov (United States)

    Prim, Ellie R.; Sitar, David J.

    2017-09-01

    The Great American Eclipse is over. Somewhat sad, is it not? Individuals who were unable to experience the event on August 21, 2017, can now cyber-observe the eclipse with Stellarium (http://www.stellarium.org). In the authors' opinion, it is fun and has many great applications in the classroom. In addition it is open source and available for Android, iOS, and Linux users. We here at Appalachian use it in our introductory astronomy labs for specific activities such as investigating coordinate systems, discovering differences between solar and sidereal days, as well as determining why your "astrological sign" is most often not your "astronomical sign."

  7. Will Jazz Survive? Thoughts on the State of the Great American Art.

    Science.gov (United States)

    Benjamin, Playthell

    1983-01-01

    Jazz is undoubtedly the great North American contribution to art, yet this art form is undermined by the White music elite which chooses instead to support institutions that perpetuate European music. When jazz is given attention in the mass media, both its Black origins and the great Black jazz artists are largely ignored. (GC)

  8. The Great American Recession and forgone healthcare: Do widened disparities between African-Americans and Whites remain?

    Science.gov (United States)

    Travers, Jasmine L; Cohen, Catherine C; Dick, Andrew W; Stone, Patricia W

    2017-01-01

    During the Great Recession in America, African-Americans opted to forgo healthcare more than other racial/ethnic groups. It is not understood whether disparities in forgone care returned to pre-recession levels. Understanding healthcare utilization patterns is important for informing subsequent efforts to decrease healthcare disparities. Therefore, we examined changes in racial disparities in forgone care before, during, and after the Great Recession. Data were pooled from the 2006-2013 National Health Interview Survey. Forgone medical, mental, and prescription care due to affordability were assessed among African-Americans and Whites. Time periods were classified as: pre-recession (May 2006-November 2007), early recession (December 2007-November 2008), late recession (December 2008-May 2010) and post-recession (June 2010-December 2013). Multivariable logistic regressions of race, interacted with time periods, were used to identify disparities in forgone care controlling for other demographics, health insurance coverage, and having a usual place for medical care across time periods. Adjusted Wald tests were performed to identify significant changes in disparities across time periods. The sample consisted of 110,746 adults. African-Americans were more likely to forgo medical care during the post- recession compared to Whites (OR = 1.16, CI = 1.06, 1.26); changes in foregone medical care disparities were significant in that they increased in the post-recession period compared to the pre-recession (OR = 1.17, CI = 1.08, 1.28 and OR = 0.89, CI = 0.77, 1.04, respectively, adjusted Wald Test p-value Great Recession and may be a result of outstanding issues related to healthcare access, cost, and quality. While health insurance is an important component of access to care, it alone should not be expected to remove these disparities due to other financial constraints. Additional strategies are necessary to close remaining gaps in care widened by the Great Recession.

  9. Water appropriation and ecosystem stewardship in the Baja desert

    OpenAIRE

    de las Heras Alejandro; Rodriguez Mario A.; Islas-Espinoza Marina

    2014-01-01

    The UNESCO San Francisco Rock Paintings polygon within El Vizcaino Biosphere Reserve in the Baja California Peninsula derives its moisture from the North American monsoon. There, ranchers have depended on the desert since the 18th century. More recently, the desert has depended on the environmental stewardship of the ranchers who have allayed mining exploitation and archaeological looting. Using a Rapid Assessment Procedure (RAP), climate data, and geographical informa...

  10. Water developments and canids in two North American deserts: a test of the indirect effect of water hypothesis.

    Directory of Open Access Journals (Sweden)

    Lucas K Hall

    Full Text Available Anthropogenic modifications to landscapes intended to benefit wildlife may negatively influence wildlife communities. Anthropogenic provisioning of free water (water developments to enhance abundance and distribution of wildlife is a common management practice in arid regions where water is limiting. Despite the long-term and widespread use of water developments, little is known about how they influence native species. Water developments may negatively influence arid-adapted species (e.g., kit fox, Vulpes macrotis by enabling water-dependent competitors (e.g., coyote, Canis latrans to expand distribution in arid landscapes (i.e., indirect effect of water hypothesis. We tested the two predictions of the indirect effect of water hypothesis (i.e., coyotes will visit areas with free water more frequently and kit foxes will spatially and temporally avoid coyotes and evaluated relative use of free water by canids in the Great Basin and Mojave Deserts from 2010 to 2012. We established scent stations in areas with (wet and without (dry free water and monitored visitation by canids to these sites and visitation to water sources using infrared-triggered cameras. There was no difference in the proportions of visits to scent stations in wet or dry areas by coyotes or kit foxes at either study area. We did not detect spatial (no negative correlation between visits to scent stations or temporal (no difference between times when stations were visited segregation between coyotes and kit foxes. Visitation to water sources was not different for coyotes between study areas, but kit foxes visited water sources more in Mojave than Great Basin. Our results did not support the indirect effect of water hypothesis in the Great Basin or Mojave Deserts for these two canids.

  11. Effects of rapid urbanization on streamflow, erosion, and sedimentation in a desert stream in the American Southwest

    Science.gov (United States)

    Whitney, John W.; Glancy, Patrick A.; Buckingham , Susan E.; Ehrenberg, Arthur C.

    2015-01-01

    Rapid urbanization has resulted in a series of sequential effects on a desert stream in the American Southwest. Lower Las Vegas Wash was a dry wash characterized by infrequent flood deposition when Las Vegas, Nevada was established in 1905. Wastewater effluent was discharged into the wash in low volumes for over 3 decades. Wastewater volumes increased commensurably with accelerated population growth during the late 20th century and created a sequence of feedback effects on the floodplain. Initially slow saturation of the valley fill created a desert oasis of dense floodplain vegetation and wetlands. Annual streamflow began in 1958 and erosion began a decade later with shallow incision in discontinuous channel segments. Increasing baseflow gradually enlarged channels; headcutting was active during the 1970s to 1984. The incised channels concentrated storm runoff, which accelerated local channel erosion, and in 1984 the headcuts were integrated during a series of monsoon floods. Wetlands were drained and most floodplain vegetation destroyed. Channel erosion continued unabated until engineering interventions began in the 21st century. No natural channel recovery occurred after initial urbanization effects because streamflow never stabilized in the late 20th century. A 6.6 M m3 sediment slug, eroded from the wash in ∼25 years, was deposited in Las Vegas Bay in Lake Mead. Falling reservoir levels during the 21st century are responsible for sediment redistribution and infilling of the bay. Close monitoring of impacts is recommended when urban wastewater and storm runoff are discharged on a desert wash. Channel interventions, when necessary, are advised in order to prevent costly engineering schemes of channel stabilization, flood control, and floodplain restoration.

  12. Biotic Processes Regulating the Carbon Balance of Desert Ecosystems - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Robert S [UNR; Smith, Stanley D [UNLV; Evans, Dave [WSU; Ogle, Kiona [ASU; Fenstermaker, Lynn [DRI

    2012-12-13

    Our results from the 10-year elevated atmospheric CO{sub 2} concentration study at the Nevada Desert FACE (Free-air CO{sub 2} Enrichment) Facility (NDFF) indicate that the Mojave Desert is a dynamic ecosystem with the capacity to respond quickly to environmental changes. The Mojave Desert ecosystem is accumulating carbon (C), and over the 10-year experiment, C accumulation was significantly greater under elevated [CO{sub 2}] than under ambient, despite great fluctuations in C inputs from year to year and even apparent reversals in which [CO{sub 2}] treatment had greater C accumulations.

  13. Resistance to invasion and resilience to fire in desert shrublands of North America

    Science.gov (United States)

    Matthew L. Brooks; Jeanne C. Chambers

    2011-01-01

    Settlement by Anglo-Americans in the desert shrublands of North America resulted in the introduction and subsequent invasion of multiple nonnative grass species. These invasions have altered presettlement fire regimes, resulted in conversion of native perennial shrublands to nonnative annual grasslands, and placed many native desert species at risk. Effective...

  14. Seeing desert as wilderness and as landscape—an exercise in visual thinking approaches

    Science.gov (United States)

    John Opie

    1979-01-01

    Based on the components and program of VRVA (Visual Resources Values Assessment), a behavioral history of the visitor's perception of the American desert is examined. Emphasis is placed upon contrasts between traditional eastern "garden-park" viewpoints and contemporary desert scenery experiences. Special attention is given to the influence of John...

  15. Landscape-scale distribution and density of raptor populations wintering in anthropogenic-dominated desert landscapes

    Science.gov (United States)

    Adam E. Duerr; Tricia A. Miller; Kerri L. Cornell Duerr; Michael J. Lanzone; Amy Fesnock; Todd E. Katzner

    2015-01-01

    Anthropogenic development has great potential to affect fragile desert environments. Large-scale development of renewable energy infrastructure is planned for many desert ecosystems. Development plans should account for anthropogenic effects to distributions and abundance of rare or sensitive wildlife; however, baseline data on abundance and distribution of such...

  16. The Great Recession and health risks in African American youth.

    Science.gov (United States)

    Chen, Edith; Miller, Gregory E; Yu, Tianyi; Brody, Gene H

    2016-03-01

    In the present study, we investigated associations of macro-economic conditions - the Great Recession - with cellular epigenetic aging, allostatic load, and self-reported health, in a group that experiences significant health disparities, African Americans. A sample of 330 African American adolescents in Georgia was followed from pre-recession (2007, M age=16.6) to post-recession (2010, M age=19.3). Economic data were collected in both 2007 and 2010. Three groups were formed to represent economic trajectories across the period of the Great Recession (stable low economic hardship, downward mobility, and stable high economic hardship). At age 19, measures of cellular epigenetic aging (derived from leukocyte DNA methylation profiles, reflecting the disparity between a person's biological and chronological age), allostatic load (composite of blood pressure, C reactive protein, cortisol, epinephrine, norepinephrine, and body mass index), and adolescent self-report of health were obtained. Linear trend analyses documented significant differences across all outcomes. The more time adolescents spent under economic hardship, the higher their epigenetic aging [estimate=1.421, SE=0.466, p=.002] and allostatic load [estimate=1.151, SE=0.375, p=.002] scores, and the worse their self-report of health [estimate=4.957, SE=1.800, p=.006]. Specific group comparisons revealed that adolescents in the downward mobility group had higher levels of allostatic load than adolescents in the stable low hardship group [p<.05]. Overall, these findings suggest that the health profiles of African American youth may in part be shaped by environmental macro-economic societal conditions, and that effects on biological markers can be detected relatively early in life. Copyright © 2015 Elsevier Inc. All rights reserved.

  17. Reclaiming freshwater sustainability in the Cadillac Desert

    Science.gov (United States)

    Sabo, John L.; Sinha, Tushar; Bowling, Laura C.; Schoups, Gerrit H.W.; Wallender, Wesley W.; Campana, Michael E.; Cherkauer, Keith A.; Fuller, Pam L.; Graf, William L.; Hopmans, Jan W.; Kominoski, John S.; Taylor, Carissa; Trimble, Stanley W.; Webb, Robert H.; Wohl, Ellen E.

    2010-01-01

    Increasing human appropriation of freshwater resources presents a tangible limit to the sustainability of cities, agriculture, and ecosystems in the western United States. Marc Reisner tackles this theme in his 1986 classic Cadillac Desert: The American West and Its Disappearing Water. Reisner's analysis paints a portrait of region-wide hydrologic dysfunction in the western United States, suggesting that the storage capacity of reservoirs will be impaired by sediment infilling, croplands will be rendered infertile by salt, and water scarcity will pit growing desert cities against agribusiness in the face of dwindling water resources. Here we evaluate these claims using the best available data and scientific tools. Our analysis provides strong scientific support for many of Reisner's claims, except the notion that reservoir storage is imminently threatened by sediment. More broadly, we estimate that the equivalent of nearly 76% of streamflow in the Cadillac Desert region is currently appropriated by humans, and this figure could rise to nearly 86% under a doubling of the region's population. Thus, Reisner's incisive journalism led him to the same conclusions as those rendered by copious data, modern scientific tools, and the application of a more genuine scientific method. We close with a prospectus for reclaiming freshwater sustainability in the Cadillac Desert, including a suite of recommendations for reducing region-wide human appropriation of streamflow to a target level of 60%.

  18. Impact of intra- versus inter-annual snow depth variation on water relations and photosynthesis for two Great Basin Desert shrubs.

    Science.gov (United States)

    Loik, Michael E; Griffith, Alden B; Alpert, Holly; Concilio, Amy L; Wade, Catherine E; Martinson, Sharon J

    2015-06-01

    Snowfall provides the majority of soil water in certain ecosystems of North America. We tested the hypothesis that snow depth variation affects soil water content, which in turn drives water potential (Ψ) and photosynthesis, over 10 years for two widespread shrubs of the western USA. Stem Ψ (Ψ stem) and photosynthetic gas exchange [stomatal conductance to water vapor (g s), and CO2 assimilation (A)] were measured in mid-June each year from 2004 to 2013 for Artemisia tridentata var. vaseyana (Asteraceae) and Purshia tridentata (Rosaceae). Snow fences were used to create increased or decreased snow depth plots. Snow depth on +snow plots was about twice that of ambient plots in most years, and 20 % lower on -snow plots, consistent with several down-scaled climate model projections. Maximal soil water content at 40- and 100-cm depths was correlated with February snow depth. For both species, multivariate ANOVA (MANOVA) showed that Ψ stem, g s, and A were significantly affected by intra-annual variation in snow depth. Within years, MANOVA showed that only A was significantly affected by spatial snow depth treatments for A. tridentata, and Ψ stem was significantly affected by snow depth for P. tridentata. Results show that stem water relations and photosynthetic gas exchange for these two cold desert shrub species in mid-June were more affected by inter-annual variation in snow depth by comparison to within-year spatial variation in snow depth. The results highlight the potential importance of changes in inter-annual variation in snowfall for future shrub photosynthesis in the western Great Basin Desert.

  19. The Last Great American Picture Show : New Hollywood Cinema in the 1970s

    NARCIS (Netherlands)

    2004-01-01

    In The Last Great American Picture Show wordt de veranderende herwaardering in kaart gebracht voor de Amerikaanse film in de jaren zeventig. Deze periode, vroeger aangeduid als het decennium van de 'lost generation', wordt meer en meer erkend als het eerste 'Nieuwe Hollywood'. In deze periode werd

  20. 77 FR 65886 - Century Metal Recycling PVT. LTD v. Dacon Logistics, LLC dba CODA Forwarding, Great American...

    Science.gov (United States)

    2012-10-31

    ... FEDERAL MARITIME COMMISSION [Docket No. 12-09] Century Metal Recycling PVT. LTD v. Dacon Logistics, LLC dba CODA Forwarding, Great American Alliance Insurance Company, Avalon Risk Management, HAPAG... Recycling Pvt. Ltd d/ b/a/CMR American, LLC (Century Metal), hereinafter ``Complainant,'' against Dacon...

  1. The voice of American botanists: the founding and establishment of the American Journal of Botany, "American botany," and the Great War (1906-1935).

    Science.gov (United States)

    Smocovitis, Vassiliki Betty

    2014-03-01

    This paper examines the crucial early history of the American Journal of Botany from the years following the founding of the Botanical Society of America in 1906 to the termination of the agreement for publication with the Brooklyn Botanic Garden in 1935. It examines the efforts of individuals like F. C. Newcombe, who did the most to raise support for the journal and became the first Editor-in-Chief, in the context of the growing numbers of professional botanists and plant scientists who were actively engaged in research requiring appropriate publication venues and in the process of forming an independent identity as "American botanists." It also examines the launching of the journal in the context of the Great War in Europe and the transition from German botany to American botany in the second decade of the 20th century.

  2. Extensive summer water pulses do not necessarily lead to canopy growth of Great Basin and northern Mojave Desert shrubs.

    Science.gov (United States)

    Snyder, K A; Donovan, L A; James, J J; Tiller, R L; Richards, J H

    2004-10-01

    Plant species and functionally related species groups from arid and semi-arid habitats vary in their capacity to take up summer precipitation, acquire nitrogen quickly after summer precipitation, and subsequently respond with ecophysiological changes (e.g. water and nitrogen relations, gas exchange). For species that respond ecophysiologically, the use of summer precipitation is generally assumed to affect long-term plant growth and thus alter competitive interactions that structure plant communities and determine potential responses to climate change. We assessed ecophysiological and growth responses to large short-term irrigation pulses over one to three growing seasons for several widespread Great Basin and northern Mojave Desert shrub species: Chrysothamnus nauseosus, Sarcobatus vermiculatus, Atriplex confertifolia, and A. parryi. We compared control and watered plants in nine case studies that encompassed adults of all four species, juveniles for three of the species, and two sites for two of the species. In every comparison, plants used summer water pulses to improve plant water status or increase rates of functioning as indicated by other ecophysiological characters. Species and life history stage responses of ecophysiological parameters (leaf N, delta15N, delta13C, gas exchange, sap flow) were consistent with several previous short-term studies. However, use of summer water pulses did not affect canopy growth in eight out of nine comparisons, despite the range of species, growth stages, and site conditions. Summer water pulses affected canopy growth only for C. nauseosus adults. The general lack of growth effects for these species might be due to close proximity of groundwater at these sites, co-limitation by nutrients, or inability to respond due to phenological canalization. An understanding of the connections between short-term ecophysiological responses and growth, for different habitats and species, is critical for determining the significance of

  3. Bringing the Great American Eclipse of 2017 to Audiences across the Nation

    Science.gov (United States)

    Young, C. A.; Mayo, L.; Cline, T. D.; Ng, C.; Stephenson, B. E.

    2015-12-01

    The August 21, 2017 eclipse across America will be seen by an estimated 500 million people from northern Canada to South America as well as parts of western Europe and Africa. Through This "Great American Eclipse" NASA in partnership with Google, the American Parks Network, American Astronomical Society, the Astronomical League, and numerous other science, education, outreach, and public communications groups and organizations will develop the approaches, resources, partnerships, and technology applications necessary to bring the excitement and the science of the August 21st, 2017 total solar eclipse across America to formal and informal audiences in the US and around the world. This effort will be supported by the highly visible and successful Sun Earth Days program and will be the main theme for Sun-Earth Days 2017.This presentation will discuss NASA's education and communication plans for the eclipse and will detail a number of specific programs and partnerships being leveraged to enhance our reach and impact.

  4. Phylogeographic and population genetic structure of bighorn sheep ( Ovis canadensis ) in North American deserts.

    Science.gov (United States)

    Buchalski, Michael R; Sacks, Benjamin N; Gille, Daphne A; Penedo, Maria Cecilia T; Ernest, Holly B; Morrison, Scott A; Boyce, Walter M

    2016-06-09

    Fossil data are ambiguous regarding the evolutionary origin of contemporary desert bighorn sheep ( Ovis canadensis subspecies). To address this uncertainty, we conducted phylogeographic and population genetic analyses on bighorn sheep subspecies found in southwestern North America. We analyzed 515 base pairs of mtDNA control region sequence and 39 microsatellites in 804 individuals from 58 locations. Phylogenetic analyses revealed 2 highly divergent clades concordant with Sierra Nevada ( O. c. sierrae ) and Rocky Mountain ( O. c. canadensis ) bighorn and showed that these 2 subspecies both diverged from desert bighorn prior to or during the Illinoian glaciation (~315-94 thousand years ago [kya]). Desert bighorn comprised several more recently diverged haplogroups concordant with the putative Nelson ( O. c. nelsoni ), Mexican ( O. c. mexicana ), and Peninsular ( O. c. cremnobates ) subspecies. Corresponding estimates of effective splitting times (~17-3 kya), and haplogroup ages (~85-72 kya) placed the most likely timeframe for divergence among desert bighorn subspecies somewhere within the last glacial maximum. Median-joining haplotype network and Bayesian skyline analyses both indicated that desert bighorn collectively comprised a historically large and haplotype-diverse population, which subsequently lost much of its diversity through demographic decline. Using microsatellite data, discriminant analysis of principle components (DAPC) and Bayesian clustering analyses both indicated genetic structure concordant with the geographic distribution of 3 desert subspecies. Likewise, microsatellite and mitochondrial-based F ST comparisons revealed significant fixation indices among the desert bighorn genetic clusters. We conclude these desert subspecies represent ancient lineages likely descended from separate Pleistocene refugial populations and should therefore be managed as distinct taxa to preserve maximal biodiversity. Los datos de fósiles sobre el origen evolutivo

  5. Great aspirations: the postwar American college counseling center.

    Science.gov (United States)

    McCarthy, Tom

    2014-02-01

    In the decade after World War II, psychologists, eager to bring the benefits of counseling to larger numbers, convinced hundreds of American colleges and universities to establish counseling centers. Inspired by the educational-vocational counseling center founded by psychologists at the University of Minnesota in 1932, Carl R. Rogers's "client-centered" methods of personal adjustment counseling, and the 400-plus college counseling centers created by the Veterans Administration to provide the educational-vocational counseling benefit promised to returning World War II servicemen under the 1944 GI Bill, these counseling psychologists created a new place to practice where important currents in psychology, higher education, and federal policy converged and where they attempted to integrate educational-vocational counseling with personal adjustment counseling based on techniques from psychotherapy. By the mid-1960s, half of America's colleges and universities had established counseling centers, and more than 90% offered students educational, vocational, and psychological counseling services, a great achievement of the first generation of counseling psychologists.

  6. Moving Beyond "Food Deserts": Reorienting United States Policies to Reduce Disparities in Diet Quality.

    Directory of Open Access Journals (Sweden)

    Jason P Block

    2015-12-01

    Full Text Available Jason Block and S. V. Subramanian explore avenues for improving the health of Americans through reducing dietary inequalities and look at whether concern over "food deserts" has been taken too far.

  7. Incidental oligotrophication of North American Great Lakes.

    Science.gov (United States)

    Evans, Mary Anne; Fahnenstiel, Gary; Scavia, Donald

    2011-04-15

    Phytoplankton production is an important factor in determining both ecosystem stability and the provision of ecosystem goods and services. The expansive and economically important North American Great Lakes are subjected to multiple stressors and understanding their responses to those stresses is important for understanding system-wide ecological controls. Here we show gradual increases in spring silica concentration (an indicator of decreasing growth of the dominant diatoms) in all basins of Lakes Michigan and Huron (USA and Canadian waters) between 1983 and 2008. These changes indicate the lakes have undergone gradual oligotrophication coincident with and anticipated by nutrient management implementation. Slow declines in seasonal drawdown of silica (proxy for seasonal phytoplankton production) also occurred, until recent years, when lake-wide responses were punctuated by abrupt decreases, putting them in the range of oligotrophic Lake Superior. The timing of these dramatic production drops is coincident with expansion of populations of invasive dreissenid mussels, particularly quagga mussels, in each basin. The combined effect of nutrient mitigation and invasive species expansion demonstrates the challenges facing large-scale ecosystems and suggest the need for new management regimes for large ecosystems.

  8. Process-based management approaches for salt desert shrublands dominated by downy brome

    Science.gov (United States)

    Downy brome grass (Bromus tectorum L.) invasion has severely altered key ecological processes such as disturbance regimes, soil nutrient cycling, community assembly, and successional pathways in semi-arid Great Basin salt desert shrublands. Restoring the structure and function of these severly alte...

  9. Effects of desert wildfires on desert tortoise (Gopherus agassizii) and other small vertebrates

    Science.gov (United States)

    Esque, T.C.; Schwalbe, C.R.; DeFalco, L.A.; Duncan, R.B.; Hughes, T.J.

    2003-01-01

    We report the results of standardized surveys to determine the effects of wildfires on desert tortoises (Gopherus agassizii) and their habitats in the northeastern Mojave Desert and northeastern Sonoran Desert. Portions of 6 burned areas (118 to 1,750 ha) were examined for signs of mortality of vertebrates. Direct effects of fire in desert habitats included animal mortality and loss of vegetation cover. A range of 0 to 7 tortoises was encountered during surveys, and live tortoises were found on all transects. In addition to desert tortoises, only small (reptiles (11 taxa) were found dead on the study areas. We hypothesize that indirect effects of fire on desert habitats might result in changes in the composition of diets and loss of vegetation cover, resulting in an increase in predation and loss of protection from temperature extremes. These changes in habitat also might cause changes in vertebrate communities in burned areas.

  10. American Sammys and French Poilus in the Great War: sport, masculinities and vulnerability.

    Science.gov (United States)

    Terret, Thierry

    2011-01-01

    The violence and duration of fighting throughout the Great War created an intense feeling of vulnerability among the men engaged in battle, which challenged their perception of manliness. When the Americans joined the war in 1917, the balance between the two opposing armies was modified and the psychological crises of French soldiers brought to an end. The confidence shown by the American soldiers and their first successes on the battlefield changed the way the French Poilus perceived their new allies. From scepticism to admiration, Frenchmen's feelings extended beyond the fighting. Indeed, by living with American soldiers in the trenches and camps behind the front, French soldiers discovered a new culture where games and sport played a major role and contributed to building manliness. The Foyers Franco-Americains du Soldat (Franco-American hostels for soldiers) provided an ideal place for the cultural transfer of a model of masculinity from Sammys to Poilus. The foyers were managed by the American YMCA and eventually reached the number of 1,500 in France during the war. These hostels afforded soldiers numerous opportunities to develop cultural and sports practices, by bringing together Americans and Frenchmen. Mainly based on the archives of the American Expeditionary Forces, the YMCA and the French Army, the paper argues that the Foyers du Soldat brought to light a new model of masculinity based on sport, which challenged the Frenchmen's vision. It aims to show the rapid transformation of masculine identity within a context of extreme vulnerability and confirms the changes in representations of men in French society at this time.

  11. Natural resource mitigation, adaptation and research needs related to climate change in the Great Basin and Mojave Desert

    Science.gov (United States)

    Hughson, Debra L.; Busch, David E.; Davis, Scott; Finn, Sean P.; Caicco, Steve; Verburg, Paul S.J.

    2011-01-01

    This report synthesizes the knowledge, opinions, and concerns of many Federal and State land managers, scientists, stakeholders, and partners from a workshop, held at the University of Nevada, Las Vegas, on April 20-22, 2010. Land managers, research scientists, and resource specialists identified common concerns regarding the potential effects of climate change on public lands and natural resources in the Great Basin and Mojave Desert and developed recommendations for mitigation, adaptation, and research needs. Water and, conversely, the effects of drought emerged as a common theme in all breakout sessions on terrestrial and aquatic species at risk, managing across boundaries, monitoring, and ecosystem services. Climate change models for the southwestern deserts predict general warming and drying with increasing precipitation variability year to year. Scientists noted that under these changing conditions the past may no longer be a guide to the future in which managers envision increasing conflicts between human water uses and sustaining ecosystems. Increasing environmental stress also is expected as a consequence of shifting ecosystem boundaries and species distributions, expansion of non-native species, and decoupling of biotic mutualisms, leading to increasingly unstable biologic communities. Managers uniformly expressed a desire to work across management and agency boundaries at a landscape scale but conceded that conflicting agency missions and budgetary constraints often impede collaboration. More and better science is needed to cope with the effects of climate change but, perhaps even more important is the application of science to management issues using the methods of adaptive management based on long-term monitoring to assess the merits of management actions. Access to data is essential for science-based land management. Basic inventories, spatial databases, baseline condition assessments, data quality assurance, and data sharing were identified as top

  12. Influence of domestic livestock grazing on American Pika (Ochotona princeps) forage and haypiling behavior in the Great Basin. Western North American Naturalist.

    Science.gov (United States)

    Constance I. Millar

    2011-01-01

    In a pilot study, I observed a relationship between domestic livestock grazing and location of American pika (Ochotona princeps) haypiles in the eastern Sierra Nevada and several Great Basin mountain ranges. Where vegetation communities adjacent to talus bases (forefields) were grazed, mean distance from the talus borders to the closest fresh...

  13. Ecological Observations of Native Geocoris pallens and G. punctipes Populations in the Great Basin Desert of Southwestern Utah

    Directory of Open Access Journals (Sweden)

    Meredith C. Schuman

    2013-01-01

    Full Text Available Big-eyed bugs (Geocoris spp. Fallén, Hemiptera: Lygaeidae are ubiquitous, omnivorous insect predators whose plant feeding behavior raises the question of whether they benefit or harm plants. However, several studies have investigated both the potential of Geocoris spp. to serve as biological control agents in agriculture and their importance as agents of plant indirect defense in nature. These studies have demonstrated that Geocoris spp. effectively reduce herbivore populations and increase plant yield. Previous work has also indicated that Geocoris spp. respond to visual and olfactory cues when foraging and choosing their prey and that associative learning of prey and plant cues informs their foraging strategies. For these reasons, Geocoris spp. have become models for the study of tritrophic plant-herbivore-predator interactions. Here, we present detailed images and ecological observations of G. pallens Stål and G. punctipes (Say native to the Great Basin Desert of southwestern Utah, including observations of their life histories and color morphs, dynamics of their predatory feeding behavior and prey choice over space and time, and novel aspects of Geocoris spp.’s relationships to their host plants. These observations open up new areas to be explored regarding the behavior of Geocoris spp. and their interactions with plant and herbivore populations.

  14. Community adaptations to an impending food desert in rural Appalachia, USA.

    Science.gov (United States)

    Miller, Wayne C; Rogalla, Denver; Spencer, Dustin; Zia, Nida; Griffith, Brian N; Heinsberg, Haylee B

    2016-01-01

    The United States Department of Agriculture (USDA) describes a food desert as an urban neighborhood or rural town without ready access to fresh, healthy, and affordable food. An estimated 2.3 million rural Americans live in food deserts. One goal of the USDA is to eliminate food deserts. However, at a time when some food deserts are being eliminated, hundreds of grocery stores are closing, causing other food deserts to arise. The literature is scarce on how a community adapts to an impending food desert. Alderson, West Virginia, USA (population 1184) rallied to face an impending food desert when the only grocery store in town closed in December 2014. This study investigated how this small rural community adapted to its oncoming food desert. A community member survey was administered to 155 Alderson families (49%) to determine how the new food desert affected family food acquisition and storage behaviors. A restaurant survey was given to the town's four restaurants to determine how the food desert affected their businesses. Sales data for a new food hub (Green Grocer) was obtained to see if this new initiative offset the negative effects of the food desert. ANOVA and t-tests were used to compare group numerical data. Two group response rates were compared by testing the equality of two proportions. Categorical data were analyzed with the χ2 or frequency distribution analysis. Group averages are reported as mean ± standard error of the mean. Significance for all analyses was set at pp=0.16) from the number before the food desert (2.8±0.3). Price comparisons among the Green Grocer and three distant supermarkets showed a 30% savings by traveling to distant supermarkets. Frequency of monthly restaurant visits did not change after the emergence of the food desert (2.98±0.54 vs 3.05±0.51, p=0.85). However, restaurant patrons requested to buy fresh produce and dairy from the restaurants to use for their own home cooking. Food pantry use increased by 43%, with

  15. New records of marginal locations for American pika (Ochotona princeps) in the Western Great Basin

    Science.gov (United States)

    Constance I. Millar; Robert D. Westfall; Diane L. Delany

    2013-01-01

    We describe 46 new site records documenting occupancy by American pika (Ochotona princeps) at 21 locations from 8 mountain regions in the western Great Basin, California, and Nevada. These locations comprise a subset of sites selected from regional surveys to represent marginal, isolated, or otherwise atypical pika locations, and to provide...

  16. Lut Desert, Iran

    Science.gov (United States)

    1981-01-01

    Iran is a large country with several desert regions. In the Dasht-E-Lut (Lut Desert) (30.5N, 58.5E) an area known as Namak-Zar, about 100 miles east of the city of Kerman, is at the center of this photograph. Some of the world's most prominent Yardangs (very long, parallel ridges and depressions) have been wind eroded in these desert dry lake bed sediments. At the left of the photo is a large field of sand dunes at right angles to the wind.

  17. Livestock grazing and the desert tortoise in the Mojave Desert

    Science.gov (United States)

    Oldemeyer, John L.

    1994-01-01

    A large part of the Mojave Desert is not in pristine condition, and some current conditions can be related to past grazing-management practices. No information could be found on densities of the desert tortoise (Gopherus agassizii) or on vegetative conditions of areas that had not been grazed to allow managers a comparison of range conditions with data on tortoises. Experimental information to assess the effect of livestock grazing on tortoises is lacking, and researchers have not yet examined whether the forage that remains after grazing is sufficient to meet the nutritional needs of desert tortoises.

  18. Are There High Meteorite Concentrations in the Atacama Desert/Chile?

    Science.gov (United States)

    Scherer, P.; Delisle, G.

    1992-07-01

    We have visited numerous regions of the Atacama desert between Copiapo (27 degrees, 15'S) and Calama (22 degrees, 25'S) to assess their potential as a high-yield meteorite concentration surface, easily exploitable by search efforts within a reasonable time frame. According to our observations, this desert is characterized by the following features: a) A high percentage of the desert consists of sloping surfaces on which soil movement occurs, presumably by very infrequent, though heavy rain. b) Vast areas of the desert are covered by a dm-thick sand layer of dark colour. Since the sand is too coarse-grained to be transported by wind it presumably resulted from in-situ weathering of rock debris derived from nearby mountains. We suspect that impacting smaller objects can easily penetrate the sand layer. c) The sand layer is typically dotted by rocks, fist-size or smaller, that are covered by a thick layer of desert paint (reddish-brown to black colour). Most country rocks are of volcanic origin (rhyolite, andesite, basalt) and are typically of grey to black colour. A noticeable colour contrast in particular to potential stony meteorites is almost nonexistent. d) Soil salts with a potential to speed up weathering processes are ubiquitous near the surface. e) The Pampa de Mejillones, 45 km north of Antofagasta, is one of the few light-coloured areas in the Atacama desert. The surface, being of Mio-Pliocene age, consists of an almost continuous layer of light-brown fossil shells (bivalves and gastropodes). Fluvially transported dark rocks from adjacent outcrops rest on top. The latter material is covered again by desert paint. Few meteorite discoveries have been reported from this area (Pampa (a),(b),(c)). f) Numerous old tire tracks, in particular around mines in operation, crisscross most areas of the Atacama. Undetected objects such as large masses of iron bodies are not likely to have remained undiscovered in great numbers any more. We conclude that the potential of

  19. Water consumption in artificial desert oasis based on net primary productivity

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Analysis of the water consumption is the basis for water allocation in oasis. However, the method of estimating oasis water consumption remains a great challenge. Based on net primary productivity (NPP) and the transpiration coefficient, a vegetation water consumption model was developed to estimate the water consumption in desert oasis in ERDAS environment. Our results demonstrated that the ecosystem in the middle reaches of the Heihe oasis consumed water of 18.41×108-21.9×108 m3 for irrigation. Without taking precipitation into account, the water consumption in farmland accounted for 77.1%-77.8% (or about 13.97×108-16.84×108 m3) of the oasis vegetation water consumption and in the farmland protection system accounting for 22%. The growing period precipitation in desert environments is about 7.02×108 m3, and the total annual precipitation is about 8.29×108 m3. The modeled water consumption of desert vegetation, however, is about 4.57×108 m3, equivalent to only 65% of the growing period precipitation or 55% of the total annual precipitation. The modeled value equals to the cumulative precipitation of greater than 5 mm, which is defined as the effective precipitation in arid desert.

  20. An ecological study of food desert prevalence and 4th grade academic achievement in New York State school districts

    Directory of Open Access Journals (Sweden)

    Seth E. Frndak

    2014-12-01

    Full Text Available Background. This ecological study examines the relationship between food desert prevalence and academic achievement at the school district level. Design and methods. Sample included 232 suburban and urban school districts in New York State. Multiple open-source databases were merged to obtain: 4th grade science, English and math scores, school district demographic composition (NYS Report Card, regional socioeconomic indicators (American Community Survey, school district quality (US Common Core of Data, and food desert data (USDA Food Desert Atlas. Multiple regression models assessed the percentage of variation in achievement scores explained by food desert variables, after controlling for additional predictors.Results. The proportion of individuals living in food deserts significantly explained 4th grade achievement scores, after accounting for additional predictors. School districts with higher proportions of individuals living in food desert regions demonstrated lower 4th grade achievement across science, English and math. Conclusions. Food deserts appear to be related to academic achievement at the school district level among urban and suburban regions. Further research is needed to better understand how food access is associated with academic achievement at the individual level.

  1. Great Importance Attached to Intangible Cultural Heritage

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Intangible Cultural Heritage on Verge of Extinction? With the acceleration of globalization and modernization, dramatic changes have taken place in China's cultural ecology: intangible cultural heritage is confronted with great challenges and a lot of orally and behaviorally transmitted cultural heritage disappear one after another; a great deal of traditional craftsmanship is on the verge of extinction; a large number of precious objects and materials of historical and cultural values are destroyed,deserted or lost in foreign countries; arbitrary misuse and excessive exploitation of intangible cultural heritage occur from time to time. Therefore, the protection of intangible cultural heritage brooks no delay.

  2. Do singing-ground surveys reflect american woodcock abundance in the western Great Lakes region?

    Science.gov (United States)

    Matthew R. Nelson,; Andersen, David E.

    2013-01-01

    The Singing-ground Survey (SGS) is the primary monitoring tool used to assess population status and trends of American woodcock (Scolopax minor). Like most broad-scale surveys, the SGS cannot be directly validated because there are no independent estimates of abundance of displaying male American woodcock at an appropriate spatial scale. Furthermore, because locations of individual SGS routes have generally remained stationary since the SGS was standardized in 1968, it is not known whether routes adequately represent the landscapes they were intended to represent. To indirectly validate the SGS, we evaluated whether 1) counts of displaying male American woodcock on SGS routes related to land-cover types known to be related to American woodcock abundance, 2) changes in counts of displaying male American woodcock through time were related to changes in land cover along SGS routes, and 3) land-cover type composition along SGS routes was similar to land-cover type composition of the surrounding landscape. In Wisconsin and Minnesota, USA, counts along SGS routes reflected known American woodcock-habitat relations. Increases in the number of woodcock heard along SGS routes over a 13-year period in Wisconsin were related to increasing amounts of early successional forest, decreasing amounts of mature forest, and increasing dispersion and interspersion of cover types. Finally, the cover types most strongly associated with American woodcock abundance were represented along SGS routes in proportion to their composition of the broader landscape. Taken together, these results suggest that in the western Great Lakes region, the SGS likely provides a reliable tool for monitoring relative abundance and population trends of breeding, male American woodcock.

  3. Russian deserters of World War I

    OpenAIRE

    Os'kin Maksim

    2014-01-01

    Desertion is one of the most active forms of ordinary resistance of the people to the state pressure during the low-popular war which is conducting for the purposes unclear for the people. At the same time, mass desertion is a manifestation of «total» war in the world conflicts of the XX century. During World War I in all armies of the world there was the desertion often accepting mass character. In the Russian army, as well as in other, deserters appeared from the war beginning. Desertion sca...

  4. A Waste of a Desert: Nevada and the Cold War Chemical Legacy

    Directory of Open Access Journals (Sweden)

    Cinzia Scarpino

    2009-12-01

    Full Text Available Taking the lead from Don DeLillo’s epic novel Underworld (1997 – with its overarching theme of “waste” functioning as its unifying metaphor and its picture of the American deserts turned into hazardous waste dumps or missile depots – this essay provides a close reading of the empty spaces of the Nevada desert, spaces that bear the mark left by the nuclear exploitation and the hazardous waste which have plagued Nevada since the Fifties. By linking the history of Nevada to the Cold War, and to the chemical legacy of those years, with its notions of “containment” and “weather control”, Scarpino argues that they be read as interwoven threads of the same discourse.

  5. "Great aspirations: The postwar American college counseling center": Correction to McCarthy (2014).

    Science.gov (United States)

    2018-05-01

    Reports an error in "Great aspirations: The postwar American college counseling center" by Tom McCarthy ( History of Psychology , 2014[Feb], Vol 17[1], 1-18). In the article, the copyright attribution was incorrect. The copyright is "In the public domain". The online version of this article has been corrected. (The following abstract of the original article appeared in record 2014-04967-001.) In the decade after World War II, psychologists, eager to bring the benefits of counseling to larger numbers, convinced hundreds of American colleges and universities to establish counseling centers. Inspired by the educational-vocational counseling center founded by psychologists at the University of Minnesota in 1932, Carl R. Rogers's "client-centered" methods of personal adjustment counseling, and the 400-plus college counseling centers created by the Veterans Administration to provide the educational-vocational counseling benefit promised to returning World War II servicemen under the 1944 GI Bill, these counseling psychologists created a new place to practice where important currents in psychology, higher education, and federal policy converged and where they attempted to integrate educational-vocational counseling with personal adjustment counseling based on techniques from psychotherapy. By the mid-1960s, half of America's colleges and universities had established counseling centers, and more than 90% offered students educational, vocational, and psychological counseling services, a great achievement of the first generation of counseling psychologists. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  6. Gopherus Agassizii (Desert Tortoise). Predation/Mountain Lions (Pre-Print)

    Energy Technology Data Exchange (ETDEWEB)

    Paul D. Greger and Philip A. Medica

    2009-01-01

    During a long-term study on tortoise growth within 3 fenced 9-ha enclosures in Rock Valley, Nevada Test Site (NTS), Nye County, Nevada, USA, tortoises have been captured annually since 1964 (Medica et al. 1975. Copeia 1975:630-643; Turner et al. 1987. Copeia 1987:974-979). Between early August and mid October 2003 we observed a significant mortality event. The Rock Valley enclosures were constructed of 6 x 6 mm mesh 1.2 m wide hardware cloth, buried 0.3 m in the soil with deflective flashing on both sides on the top to restrict the movement of small mammals and lizards from entering or leaving the enclosures (Rundel and Gibson 1996, Ecological communities and process in a Mojave Desert ecosystem: Rock Valley, Nevada, Cambridge University Press, Great Britain. 369 pp.). On August 6, 2003, the carcass of an adult female Desert Tortoise No.1411 (carapace length 234 mm when alive) was collected while adult male tortoise No.4414 (carapace length 269 mm) was observed alive and in good health on the same day. Subsequently the carcass of No.4414 was found on October 16, 2003. Between October 16-17, 2003, the remains of 6 (5 adult and 1 juvenile) Desert Tortoises were found, some within each of the 3 enclosures in Rock Valley. A seventh adult tortoise was found on September 26, 2006, its death also attributed to the 2003 mortality event based upon the forensic evidence. Each of the 7 adult Desert Tortoises had the central portion of their carapace broken open approximately to the dorsal portion of the marginal scutes while the plastron was still intact (Figure 1A). Adjacent to 7 of the 8 remains we located numerous bone fragments including parts of the carapace and limbs as well as dried intestines in a nearby Range Rhatany (Krameria parvifolia) shrub. The significance of the frequent use of this shrub is puzzling. Three of the Desert Tortoise shell remains possessed distinctive intercanine punctures measuring 55-60 mm center to center indicating that this was an adult

  7. Minerals in deserts

    International Nuclear Information System (INIS)

    Smith, G.I.

    1982-01-01

    Almost any kind of mineral deposit can occur in desert areas, and the lack of vegetation and soil cover makes finding them easier. Some kinds of deposits, though, are more likely to occur in deserts than elsewhere. Some of these result from processes genetically related to the present desert climate that improved lower grade deposits of ore. One such process, termed secondary enrichment, is most effective in areas with deep water tables, and many low-grade copper, silver, and uranium deposits have been converted into mineable ore by the downward migration and redeposition of soluble metals. In a desert terrane, placer processes are effective whenever running water flowing over steep slopes erodes outcropping ore bodies and transports and concentrates the heavier ore minerals at lower levels, thus converting low-grade or hard-to-mine bedrock deposits into economically workable concentrations. Other kinds of deposits are better preserved in deserts because the lower rainfall at the surface, and the lower volume of flow and the greater depths to groundwater, result in less destruction of soluble ores; deposits of salines and phosphates are the most notable ores affected by these factors. Still other ore deposits are created as a consequence of the arid climate, mostly because the high evaporation rates operating on standing bodies of water produce brines that can lead directly to concentrations of salts and indirectly to secondary minerals, such as zeolites, that are produced by reaction of silicate minerals with saline waters

  8. Russian deserters of World War I

    Directory of Open Access Journals (Sweden)

    Os'kin Maksim

    2014-10-01

    Full Text Available Desertion is one of the most active forms of ordinary resistance of the people to the state pressure during the low-popular war which is conducting for the purposes unclear for the people. At the same time, mass desertion is a manifestation of «total» war in the world conflicts of the XX century. During World War I in all armies of the world there was the desertion often accepting mass character. In the Russian army, as well as in other, deserters appeared from the war beginning. Desertion scales in the Russian army explained as objective factors - diffi cult fights, shortage of supply, defeat at the front, and subjective - unwillingness to participate in war, melancholy for the house, desire to help a family the work. Desertion in different years of war had various forms. If at the beginning of war there were mainly «self-arrows», in 1915, during defeats at the front - evasion from entrenchments. By the end of 1916, because of the general fatigue from war, desertion takes the real form - flight from the front to the back. After February revolution desertion becomes mass in which hundreds thousands military personnel take part already. Disorder of army and development of revolutionary process extremely strengthen desertion scales that is explained by the actual lack of punishment for this crime. Destruction of the Russian state during revolution became the main reason of coming to power of Bolsheviks, an exit of Russia from war and the army demobilization which essential part in 1917 already deserted from the front.

  9. Landscape-scale distribution and density of raptor populations wintering in anthropogenic-dominated desert landscapes

    Science.gov (United States)

    Duerr, Adam E.; Miller, Tricia A.; Cornell Duerr, Kerri L; Lanzone, Michael J.; Fesnock, Amy; Katzner, Todd E.

    2015-01-01

    Anthropogenic development has great potential to affect fragile desert environments. Large-scale development of renewable energy infrastructure is planned for many desert ecosystems. Development plans should account for anthropogenic effects to distributions and abundance of rare or sensitive wildlife; however, baseline data on abundance and distribution of such wildlife are often lacking. We surveyed for predatory birds in the Sonoran and Mojave Deserts of southern California, USA, in an area designated for protection under the “Desert Renewable Energy Conservation Plan”, to determine how these birds are distributed across the landscape and how this distribution is affected by existing development. We developed species-specific models of resight probability to adjust estimates of abundance and density of each individual common species. Second, we developed combined-species models of resight probability for common and rare species so that we could make use of sparse data on the latter. We determined that many common species, such as red-tailed hawks, loggerhead shrikes, and especially common ravens, are associated with human development and likely subsidized by human activity. Species-specific and combined-species models of resight probability performed similarly, although the former model type provided higher quality information. Comparing abundance estimates with past surveys in the Mojave Desert suggests numbers of predatory birds associated with human development have increased while other sensitive species not associated with development have decreased. This approach gave us information beyond what we would have collected by focusing either on common or rare species, thus it provides a low-cost framework for others conducting surveys in similar desert environments outside of California.

  10. Climate change and climate systems influence and control the atmospheric dispersion of desert dust: implications for human health

    Science.gov (United States)

    Griffin, Dale W.; Ragaini, Richard C.

    2010-01-01

    The global dispersion of desert dust through Earth’s atmosphere is greatly influenced by temperature. Temporal analyses of ice core data have demonstrated that enhanced dust dispersion occurs during glacial events. This is due to an increase in ice cover, which results in an increase in drier terrestrial cover. A shorter temporal analysis of dust dispersion data over the last 40 years has demonstrated an increase in dust transport. Climate systems or events such as the North Atlantic Oscillation, the Indian Ocean subtropical High, Pacific Decadal Oscillation, and El Nino-Sothern Oscillation are known to influence global short-term dust dispersion occurrence and transport routes. Anthropogenic influences on dust transport include deforestation, harmful use of topsoil for agriculture as observed during the American Dust Bowl period, and the creation of dry seas (Aral Sea) and lakes (Lake Owens in California and Lake Chad in North Africa) through the diversion of source waters (for irrigation and drinking water supplies). Constituents of desert dust both from source regions (pathogenic microorganisms, organic and inorganic toxins) and those scavenged through atmospheric transport (i.e., industrial and agricultural emissions) are known to directly impact human and ecosystem health. This presentation will present a review of global scale dust storms and how these events can be both a detriment and benefit to various organisms in downwind environments.

  11. Ploidy race distributions since the Last Glacial Maximum in the North American desert shrub, Larrea tridentata

    Science.gov (United States)

    Hunter, K.L.; Betancourt, J.L.; Riddle, B.R.; Van Devender, T. R.; Cole, K.L.; Geoffrey, Spaulding W.

    2000-01-01

    1 A classic biogeographic pattern is the alignment of diploid, tetraploid and hexaploid races of creosote bush (Larrea tridentata) across the Chihuahuan, Sonoran and Mohave Deserts of western North America. We used statistically robust differences in guard cell size of modern plants and fossil leaves from packrat middens to map current and past distributions of these ploidy races since the Last Glacial Maximum (LGM). 2 Glacial/early Holocene (26-10 14C kyr BP or thousands of radiocarbon years before present) populations included diploids along the lower Rio Grande of west Texas, 650 km removed from sympatric diploids and tetraploids in the lower Colorado River Basin of south-eastern California/south-western Arizona. Diploids migrated slowly from lower Rio Grande refugia with expansion into the northern Chihuahuan Desert sites forestalled until after ???4.0 14C kyr BP. Tetraploids expanded from the lower Colorado River Basin into the northern limits of the Sonoran Desert in central Arizona by 6.4 14C kyr BP. Hexaploids appeared by 8.5 14C kyr BP in the lower Colorado River Basin, reaching their northernmost limits (???37??N) in the Mohave Desert between 5.6 and 3.9 14C kyr BP. 3 Modern diploid isolates may have resulted from both vicariant and dispersal events. In central Baja California and the lower Colorado River Basin, modern diploids probably originated from relict populations near glacial refugia. Founder events in the middle and late Holocene established diploid outposts on isolated limestone outcrops in areas of central and southern Arizona dominated by tetraploid populations. 4 Geographic alignment of the three ploidy races along the modern gradient of increasingly drier and hotter summers is clearly a postglacial phenomenon, but evolution of both higher ploidy races must have happened before the Holocene. The exact timing and mechanism of polyploidy evolution in creosote bush remains a matter of conjecture. ?? 2001 Blackwell Science Ltd.

  12. Desert pioneers go high tech in uranium project

    International Nuclear Information System (INIS)

    1988-01-01

    The Kintyre uranium deposit discovered in 1985 in Western Australia's Great Sandy Desert by CRA Exploration is a highly competitive, easy to mine deposit, estimated at 35,000 tonnes of uranium oxide. Since its discovery CRA has spent $20 million on evaluation drilling and exploration and will spend another $10 million in 1988. Despite its remoteness the latest technology is being used, with sophisticated computer and assaying facilities, including an automatic X-ray fluorescence spectrometer, being established on site. A CRA-built radiometric ore sorter is being tested there which could cut ore processing costs

  13. EFFECTS OF PLANT SIZE ON PHOTOSYNTHESIS AND WATER RELATIONS IN THE DESERT SHRUB PROSOPIS GLANDULOSA (FABACEAE)

    Science.gov (United States)

    The Jornada del Muerto basin of the Chihuahuan Desert of southern New Mexico, USA, has undergone a marked transition of plant communities. Shrubs such as mesquite (Prosopis glandulosa) have greatly increased or now dominate in areas that were previously dominated by perennial gra...

  14. Respondence and feedback of modern sand deserts to climate change--A case study in Gurbantunggut Desert

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The research on the respondence and feedback of modern sand deserts to the climate change is an important component part in the studies on the global climate change. Deserts respond to the climate change, meanwhile, they affect the climate with their feedback of peculiar environment during the respondence. Many researches on desert climate have been carried out at home and abroad. However, there is little research on the respondence and feedback of modern fixed, semi-fixed and mobile deserts in arid areas to the climate change, in which the factor analysis as well as the parameter changing effects is especially the difficult problem all along. In this note, the parameters of the respondence and feedback of Gurbantunggut Desert to the climate change are measured and analyzed, some variable parameters of water-heat exchange are obtained, and a numerical model of desertification is developed according to a series of climate change of about 40 years and the variable relations of meteorological and physical features of the sand surface in Gurbantunggut Desert.

  15. Influence of surface roughness of a desert

    Science.gov (United States)

    Sud, Y. C.; Smith, W. E.

    1984-01-01

    A numerical simulation study, using the current GLAS climate GCM, was carried out to examine the influence of low bulk aerodynamic drag parameter in the deserts. The results illustrate the importance of yet another feedback effect of a desert on itself, that is produced by the reduction in surface roughness height of land once the vegetation dies and desert forms. Apart from affecting the moisture convergence, low bulk transport coefficients of a desert lead to enhanced longwave cooling and sinking which together reduce precipitation by Charney's (1975) mechanism. Thus, this effect, together with albedo and soil moisture influence, perpetuate a desert condition through its geophysical feedback effect. The study further suggests that man made deserts is a viable hypothesis.

  16. What Caused the Great Depression?

    Science.gov (United States)

    Caldwell, Jean; O'Driscoll, Timothy G.

    2007-01-01

    Economists and historians have struggled for almost 80 years to account for the American Great Depression, which began in 1929 and lasted until the early years of World War II. In this article, the authors discuss three major schools of thought on the causes of the Great Depression and the long failure of the American economy to return to full…

  17. Book review: Diane Ravitch "The death and life of the great American school system". New York: Basic Books , 2010

    Directory of Open Access Journals (Sweden)

    Beals K.

    2015-09-01

    Full Text Available The current paper is a translation of Katharine Beals' review of the book "The death and life of the great American school system" by Diane Ravich. The article analyses the views on the causes of the inefficiency of the American school system expressed by Ravich, as well as the ways of its improvement suggested by her. A change of stance compared to her previous works is also noted. Translator: Vinogradova K.N.

  18. Leaching characteristics of Wadi Belih uraniferous Hammamat sediments,eastern desert,Egypt

    International Nuclear Information System (INIS)

    Mahdy, M.A.; EL-Hazek, M.N.

    1998-01-01

    This work deals with the direct chemical treatment of Wadi Belih uraniferous ore material using the agitation leaching technique. The study ore is mainly localized in siltstones belonging to the Hammamat sediments situated in the northern part of the eastern desert. The uranium mineral in the ore are mainly represented by the silicate mineral uranophane, the vanadate mineral tyuyamunite and to a laser extent the sulphate mineral shroekingerite, both acid (sulphuric acid) alkaline (sodium carbonate and bicarbonate) leaching methods have been applied beside sodium and ferric chlorides. The latter leaching reagents are greatly beneficial in removing radium together with uranium, a matter which is greatly important for environmental concerns

  19. Effects of artificial sand fixing on community characteristics of a rare desert shrub.

    Science.gov (United States)

    Liu, Huiliang; Tao, Ye; Qiu, Dong; Zhang, Daoyuan; Zhang, Yongkuan

    2013-10-01

    Eremosparton songoricum (Fabaceae) is a rare, native, clonal small shrub of the deserts of central Asia. Although human activities have greatly fragmented the distribution of E. songoricum, it occurs in areas where artificial sand fixing (AS) has been implemented. We sought to explore whether AS promotes survival and growth of E. songoricum. In the Gurbantunggut Desert of northwestern China in June 2010, we established 10 plots in an area where sand fixing occurred (5-10 years previously) and 11 plots on original sand substrate on which some plants had settled without fixing sand. Sand fixing changed soil properties and biological characteristics in sand-fixed plots. The soil surface where sand fixing occurred was covered by algal crusts and some lichen, but not bare sand (BS). Soil nutrients; water content of deep soil (30-150 cm); overall plant and herbaceous species richness, diversity, abundance, and cover; above- and belowground biomass; and cover, biomass, and height of E. songoricum in the sand-fixed plots were significantly greater than in plots of BS. However, distribution of E. songoricum individuals in the 2 types of plots did not differ. Our results indicate AS may enhance survival of E. songoricum and increase the overall diversity and stability of the desert plant community. We suggest AS as a way to protect this rare desert plant in situ. © 2013 Society for Conservation Biology.

  20. Holocene landscape response to seasonality of storms in the Mojave Desert

    Science.gov (United States)

    Miller, D.M.; Schmidt, K.M.; Mahan, S.A.; McGeehin, J.P.; Owen, L.A.; Barron, J.A.; Lehmkuhl, F.; Lohrer, R.

    2010-01-01

    New optically stimulated and radiocarbon ages for alluvial fan and lake deposits in the Mojave Desert are presented, which greatly improves the temporal resolution of surface processes. The new Mojave Desert climate-landscape record is particularly detailed for the late Holocene. Evidence from ephemeral lake deposits and landforms indicates times of sustained stream flow during a wet interval of the latter part of the Medieval Warm Period at ca. AD 1290 and during the Little Ice Age at ca. AD 1650. The former lakes postdate megadroughts of the Medieval Warm Period, whereas the latter match the Maunder Minimum of the Little Ice Age. Periods of alluvial fan aggradation across the Mojave Desert are 14-9 cal ka and 6-3 cal ka. This timing largely correlates to times of increased sea-surface temperatures in the Gulf of California and enhanced warm-season monsoons. This correlation suggests that sustained alluvial fan aggradation may be driven by intense summer-season storms. These data suggest that the close proximity of the Mojave Desert to the Pacific Ocean and the Gulf of California promotes a partitioning of landscape-process responses to climate forcings that vary with seasonality of the dominant storms. Cool-season Pacific frontal storms cause river flow, ephemeral lakes, and fan incision, whereas periods of intense warm-season storms cause hillslope erosion and alluvial fan aggradation. The proposed landscape-process partitioning has important implications for hazard mitigation given that climate change may increase sea-surface temperatures in the Gulf of California, which indirectly could increase future alluvial fan aggradation.

  1. The geochemical associations of nitrate and naturally formed perchlorate in the Mojave Desert, California, USA

    Science.gov (United States)

    Lybrand, Rebecca A.; Michalski, Greg; Graham, Robert C.; Parker, David R.

    2013-03-01

    Perchlorate is a widely studied environmental contaminant that may adversely affect human health, and whose natural occurrence has emerged as a subject of great interest. Naturally formed perchlorate has been found to co-occur with nitrate in arid environments worldwide, but the relationship is not fully understood in the desert soils of the southwestern United States. The main objective of this research was to explore the origin, pedogenic distribution, and possible preservation of perchlorate and nitrate in the Mojave Desert mud hill deposits of California and to determine if the co-occurrence of putatively natural perchlorate was significantly correlated with nitrate in these soils. We identified 39 soil horizons in the Mojave Desert, California that contained reportable levels of perchlorate (MRL >165 μg kg-1) with a maximum concentration of 23 mg kg-1. A weak yet significant correlation was observed between perchlorate and nitrate (r2 = 0.321∗∗∗), which could be indicative of similar mechanisms of accumulation. When compared to published data for the Atacama Desert, the Mojave Desert perchlorate concentrations were remarkably lower for a given nitrate concentration. Oxygen isotopes in the nitrate were examined to identify variation within the Mojave Desert field sites, and to compare with the available literature for the Atacama Desert. The Mojave Desert Δ17O values ranged from 7‰ to 13‰, indicating a mixture of biologically and atmospherically-derived nitrate. An investigation of the distribution of perchlorate among soil horizons revealed that over sixty percent of the samples containing perchlorate were from C horizons while only twenty percent of the samples were from B horizons and even fewer in the overlying A horizons. Soil chemical, morphologic, and geologic characteristics of the soils suggest that the perchlorate, nitrate and/or other soluble salts have moved in a "bottom-up" manner wherein the salts were deposited in strata through

  2. Plant-water relationships in the Great Basin Desert of North America derived from Pinus monophylla hourly dendrometer records

    Science.gov (United States)

    Biondi, Franco; Rossi, Sergio

    2015-08-01

    Water is the main limiting resource for natural and human systems, but the effect of hydroclimatic variability on woody species in water-limited environments at sub-monthly time scales is not fully understood. Plant-water relationships of single-leaf pinyon pine ( Pinus monophylla) were investigated using hourly dendrometer and environmental data from May 2006 to October 2011 in the Great Basin Desert, one of the driest regions of North America. Average radial stem increments showed an annual range of variation below 1.0 mm, with a monotonic steep increase from May to July that yielded a stem enlargement of about 0.5 mm. Stem shrinkage up to 0.2 mm occurred in late summer, followed by an abrupt expansion of up to 0.5 mm in the fall, at the arrival of the new water year precipitation. Subsequent winter shrinkage and enlargement were less than 0.3 mm each. Based on 4 years with continuous data, diel cycles varied in both timing and amplitude between months and years. Phase shifts in circadian stem changes were observed between the growing season and the dormant one, with stem size being linked to precipitation more than to other water-related indices, such as relative humidity or soil moisture. During May-October, the amplitude of the phases of stem contraction, expansion, and increment was positively related to their duration in a nonlinear fashion. Changes in precipitation regime, which affected the diel phases especially when lasting more than 5-6 h, could substantially influence the dynamics of water depletion and replenishment in single-leaf pinyon pine.

  3. Microbial rRNA sequencing analysis of evaporative cooler indoor environments located in the Great Basin Desert region of the United States†

    Science.gov (United States)

    Lemons, Angela R.; Hogan, Mary Beth; Gault, Ruth A.; Holland, Kathleen; Sobek, Edward; Olsen-Wilson, Kimberly A.; Park, Yeonmi; Park, Ju-Hyeong; Gu, Ja Kook; Kashon, Michael L.; Green, Brett J.

    2017-01-01

    Recent studies conducted in the Great Basin Desert region of the United States have shown that skin test reactivity to fungal and dust mite allergens are increased in children with asthma or allergy living in homes with evaporative coolers (EC). The objective of this study was to determine if the increased humidity previously reported in EC homes leads to varying microbial populations compared to homes with air conditioners (AC). Children with physician-diagnosed allergic rhinitis living in EC or AC environments were recruited into the study. Air samples were collected from the child's bedroom for genomic DNA extraction and metagenomic analysis of bacteria and fungi using the Illumina MiSeq sequencing platform. The analysis of bacterial populations revealed no major differences between EC and AC sampling environments. The fungal populations observed in EC homes differed from AC homes. The most prevalent species discovered in AC environments belonged to the genera Cryptococcus (20%) and Aspergillus (20%). In contrast, the most common fungi identified in EC homes belonged to the order Pleosporales and included Alternaria alternata (32%) and Phoma spp. (22%). The variations in fungal populations provide preliminary evidence of the microbial burden children may be exposed to within EC environments in this region. PMID:28091681

  4. Desertions in nineteenth-century shipping: modelling quit behaviour

    OpenAIRE

    Jari Ojala; Jaakko Pehkonen; Jari Eloranta

    2013-01-01

    Ship jumping in foreign ports was widespread throughout the age of sail. Desertion by seamen was illegal, it occurred abroad, and men who deserted only seldom returned home. We analyse desertion quantitatively and link it to the broader question of quit behaviour and labour turnover. Though the better wages paid at the foreign ports were the main reason for desertion, the regression model of the determinants of desertion indicates that outside opportunities, such as migration, and monetary in...

  5. Effect of desertification on productivity in a desert steppe.

    Science.gov (United States)

    Tang, Zhuangsheng; An, Hui; Deng, Lei; Wang, Yingying; Zhu, Guangyu; Shangguan, Zhouping

    2016-06-14

    Desertification, one of the most severe types of land degradation in the world, is of great importance because it is occurring, to some degree, on approximately 40% of the global land area and is affecting more than 1 billion people. In this study, we used a space-for-time method to quantify the impact of five different desertification regimes (potential (PD), light (LD), moderate (MD), severe (SD), and very severe (VSD)) on a desert steppe ecosystem in northern China to examine the relationship between the productivity of the vegetation and soil properties and to determine the mechanism underlying the effects of desertification on productivity. Our results showed that the effects of desertification on TP (total phosphorus) and AP (available phosphorus) were not significant, and desertification decreased productivity in the desert steppe as a result of direct changes to soil physical properties, which can directly affect soil chemical properties. Therefore, intensive grassland management to improve soil quality may result in the long-term preservation of ecosystem functions and services.

  6. HIGH FOLIAR NITROGEN IN DESERT SHRUBS: AN IMPORTANT ECOSYSTEM TRAIT OR DEFECTIVE DESERT DOCTRINE?

    Science.gov (United States)

    Nitrogen concentrations in green and senesced leaves of perennial desert shrubs were compiled from a worldwide literature search to test the validity of the doctrine that desert shrubs produce foliage and leaf litter much richer in nitrogen than that in the foliage of plants from...

  7. Rural childhoods in Egypt's desert lands

    DEFF Research Database (Denmark)

    Adriansen, Hanne Kirstine

    Based on fieldwork in Egypt’s desert lands, this paper discusses rural childhoods in an area experiencing rapid social and cultural change. Since 1987, the Egyptian Government has made new villages in the desert as a means to increase agricultural production and solving problems of unemployment....... Many settlers move to the Mubarak villages in order to give their children a good start in life. The desert villages are associated with a type of ‘rural idyll’. The process of settling in the desert impacts upon the children’s possible pathways to adulthood and their identities and social......’s new roles impact upon the children’s lives. The social contexts shaping the desert childhoods are in some ways more similar to contexts in ‘developed’ countries than in other parts of rural Egypt. The paper ends up by contrasting ideas of rural childhoods in Egypt with those found in ‘developed...

  8. Desert tortoise use of burned habitat in the Eastern Mojave desert

    Science.gov (United States)

    Drake, Karla K.; Esque, Todd C.; Nussear, Kenneth E.; DeFalco, Lesley; Scoles, Sara; Modlin, Andrew T.; Medica, Philip A.

    2015-01-01

    Wildfires burned 24,254 ha of critical habitat designated for the recovery of the threatened Mojave desert tortoise (Gopherus agassizii) in southern Nevada during 2005. The proliferation of non-native annual grasses has increased wildfire frequency and extent in recent decades and continues to accelerate the conversion of tortoise habitat across the Mojave Desert. Immediate changes to vegetation are expected to reduce quality of critical habitat, yet whether tortoises will use burned and recovering habitat differently from intact unburned habitat is unknown. We compared movement patterns, home-range size, behavior, microhabitat use, reproduction, and survival for adult desert tortoises located in, and adjacent to, burned habitat to understand how tortoises respond to recovering burned habitat. Approximately 45% of home ranges in the post-fire environment contained burned habitat, and numerous observations (n = 12,223) corroborated tortoise use of both habitat types (52% unburned, 48% burned). Tortoises moved progressively deeper into burned habitat during the first 5 years following the fire, frequently foraging in burned habitats that had abundant annual plants, and returning to adjacent unburned habitat for cover provided by intact perennial vegetation. However, by years 6 and 7, the live cover of the short-lived herbaceous perennial desert globemallow (Sphaeralcea ambigua) that typically re-colonizes burned areas declined, resulting in a contraction of tortoise movements from the burned areas. Health and egg production were similar between burned and unburned areas indicating that tortoises were able to acquire necessary resources using both areas. This study documents that adult Mojave desert tortoises continue to use habitat burned once by wildfire. Thus, continued management of this burned habitat may contribute toward the recovery of the species in the face of many sources of habitat loss.

  9. Potential for deserts to supply reliable renewable electric power

    Science.gov (United States)

    Labordena, Mercè; Lilliestam, Johan

    2015-04-01

    To avoid dangerous climate change, the electricity systems must be decarbonized by mid-century. The world has sufficient renewable electricity resources for complete power sector decarbonization, but an expansion of renewables poses several challenges for the electricity systems. First, wind and solar PV power are intermittent and supply-controlled, making it difficult to securely integrate this fluctuating generation into the power systems. Consequently, power sources that are both renewable and dispatchable, such as biomass, hydro and concentrating solar power (CSP), are particularly important. Second, renewable power has a low power density and needs vast areas of land, which is problematic both due to cost reasons and due to land-use conflicts, in particular with agriculture. Renewable and dispatchable technologies that can be built in sparsely inhabited regions or on land with low competition with agriculture would therefore be especially valuable; this land-use competition greatly limits the potential for hydro and biomass electricity. Deserts, however, are precisely such low-competition land, and are at the same time the most suited places for CSP generation, but this option would necessitate long transmission lines from remote places in the deserts to the demand centers such as big cities. We therefore study the potential for fleets of CSP plants in the large deserts of the world to produce reliable and reasonable-cost renewable electricity for regions with high and/or rapidly increasing electricity demand and with a desert within or close to its borders. The regions in focus here are the European Union, North Africa and the Middle East, China and Australia. We conduct the analysis in three steps. First, we identify the best solar generation areas in the selected deserts using geographic information systems (GIS), and applying restrictions to minimize impact on biodiversity, soils, human heath, and land-use and land-cover change. Second, we identify

  10. Cost estimates for Operation Desert Shield/Desert Storm: a budgetary analysis

    OpenAIRE

    Johnson, J. Andrew.

    1991-01-01

    Operation Desert Shield/Desert Storm (DS/DS) presented unique challenges for estimating the cost of that conflict. This analysis reviews the cost estimates and methodologies developed for that purpose by DoD, CBO and GAO. It considers the budget climate and the role of foreign cash and in-kind contributions. Finally, it reviews the budgeting innovations used to provide and monitor DS/DS defense spending. At the outset of the crisis, costs were estimated to determine the defense funding requir...

  11. Chihuahuan Deserts Ecoregion: Chapter 27 in Status and trends of land change in the Western United States--1973 to 2000

    Science.gov (United States)

    Ruhlman, Jana; Gass, Leila; Middleton, Barry

    2012-01-01

    The Chihuahuan Desert is the largest of the North American deserts, extending from southern New Mexico and Texas deep into Mexico, with approximately 90 percent of its area falling south of the United States–Mexico border (Lowe, 1964, p. 24). The Chihuahuan Deserts Ecoregion covers approximately 174,472 km2 (67,364 mi2) within the United States, including much of west Texas, southern New Mexico, and a small portion of southeastern Arizona (Omernik, 1987; U.S. Environmental Protection Agency, 1997). The ecoregion is generally oriented from northwest to southeast, with the Madrean Archipelago Ecoregion to the west; the Arizona/New Mexico Mountains, Arizona/New Mexico Plateau, Southwestern Tablelands, and Western High Plains Ecoregions to the north; and the Edwards Plateau and Southern Texas Plains Ecoregions to the east (fig. 1).

  12. Transforming the urban food desert from the grassroots up: a model for community change.

    Science.gov (United States)

    Lewis, LaVonna Blair; Galloway-Gilliam, Lark; Flynn, Gwendolyn; Nomachi, Jonathan; Keener, LaTonya Chavis; Sloane, David C

    2011-01-01

    Confronted by continuing health disparities in vulnerable communities, Community Health Councils (CHC), a nonprofit community-based organization in South Los Angeles, worked with the African Americans Building a Legacy of Health Coalition and research partners to develop a community change model to address the root causes of health disparities within the community's African American population. This article discusses how the CHC Model's development and application led to public policy interventions in a "food desert." The CHC Model provided a systematic approach to engaging impacted communities in support of societal level reforms, with the goal to influence health outcomes.

  13. Physiological adaptation in desert birds

    NARCIS (Netherlands)

    Williams, JB; Tieleman, BI; Williams, Joseph B.

    We call into question the idea that birds have not evolved unique physiological adaptations to desert environments. The rate at which desert larks metabolize energy is lower than in mesic species within the same family, and this lower rate of living translates into a lower overall energy requirement

  14. Amazonian magnetostratigraphy: Dating the first pulse of the Great American Faunal Interchange

    Science.gov (United States)

    Campbell, Kenneth E., Jr.; Prothero, Donald R.; Romero-Pittman, Lidia; Hertel, Fritz; Rivera, Nadia

    2010-04-01

    The chronostratigraphy of the youngest Neogene deposits of the Amazon Basin, which comprise the Madre de Dios Formation in eastern Peru, remains unresolved. Although 40Ar/ 39Ar dates on two volcanic ashes from this formation in Peru provide critical baseline data points, stratigraphic correlations among scattered riverine outcrops in adjacent drainage basins remain problematic. To refine the chronostratigraphy of the Madre de Dios Formation, we report here the magnetostratigraphy of an outcrop on the Madre de Dios River in southeastern Peru. A total of 18 polarity zones was obtained in the ˜65-m-thick Cerro Colorado section, which we correlate to magnetozones Chrons C4Ar to C2An (9.5-3.0 Ma) based on the prior 40Ar/ 39Ar dates. These results confirm the late Miocene age of a gomphothere recovered from the Ipururo Formation, which underlies the late Miocene Ucayali Unconformity at the base of the Cerro Colorado outcrop. The results also support earlier interpretations of a late Miocene age for other fossils of North American mammals recovered from basal conglomeratic deposits of the Madre de Dios Formation immediately above the Ucayali Unconformity. These mammals include other gomphotheres, peccaries, and tapirs, and their presence in South America in the late Miocene is recognized as part of the first pulse of the Great American Faunal Interchange.

  15. GENETIC ANALYSIS OF THE CHINESE MITTEN CRAB (ERIOCHEIR SINENSIS) INTRODUCED TO THE NORTH AMERICAN GREAT LAKES AND ST. LAWRENCE SEAWAY

    Science.gov (United States)

    The Chinese mitten crab (Eriocheir sinensis) is a globally invasive organism, with established non-native populations in Europe and California, USA. Since 1965, there have been sixteen confirmed catches of E. sinensis in the North American Great Lakes and their associated waterw...

  16. GOPHERUS AGASSIZII (Desert Tortoise)

    International Nuclear Information System (INIS)

    JAMES L. BOONE, DANNY L. RAKESTRAW, AND KURT R. RAUTENSTRAUCH

    1997-01-01

    GOPHERLTS AGAISSIZII (Desert Tortoise). Predation. A variety of predators, most notably coyotes (Canis Iatrans) and Common Ravens (Corvis corau) have been reported to prey on hatchling desert tortoises (Emst et al. 1994). Turtles of the United States and Canada (Smithsonian Institution Press, Washington, D.C. 578 pp.). Here, we report an observation of a hatchling tortoise, fitted with a radiotransmitter, that was preyed upon by native fire ants (Solenopsis sp.) in the eastern Mojave Desert at Yucca Mountain, Nevada (36 degrees 50 minutes N, 116 degree 25 minutes E). On 8/27/94, tortoise No.9315 (carapace length = 45 mm, age = 5 d) was found alive with eyes, chin, and parts of the head and legs being eaten by ants. The tortoise was alive, but lethargic, and responded little when touched. Eight of 74 other radiomarked hatchlings monitored at Yucca Mountain during 1992-1994 were found dead with fire ants on their carcass 3-7 days after the hatchlings emerged from their nests. It is not known whether those tortoises were killed by ants or were being scavenged when found. While imported fire ants (S. invicta) have long been known to kill hatchling gopher tortoises (G. polyphemus; Mount 1981. J. Alabama Acad. Sci. 52: 71-78), native fire ants have previously not been implicated as predators of desert tortoises. However, only 1 of 75 (or at worst 9 of 75) was killed by fire ants, suggesting that although fire ants do kill hatchlings, they were not important predators on desert tortoises during this study. Tortoise specimens were deposited at the University of California at Berkeley

  17. The Great Gatsby and the Collapse of American Dream

    Institute of Scientific and Technical Information of China (English)

    逄红

    2014-01-01

    Gatsby's dream is a typical American Dream. His failure signified the decay of the American post-war spirit. His death belled the alarm for the other disillusioned people from fantasy dreams and set them to reconsider the social reality.This thesis would discuss the collapse of the Gatsby's dream and that of American dream based on the book plot and the background of 1920s.

  18. Distribution patterns of terricolous and saxicolous lichens in extreme desert conditions

    Science.gov (United States)

    Temina, M.

    2012-04-01

    The investigation of biodiversity in stressful habitats is of great interest because it elucidates relationships between organisms and their environment, as well as revealing the mechanisms of their survival and adaptation to extreme conditions. Deserts represent such stressful habitats where harsh climate and limited resources greatly influence the formation of biota. In order to understand the link between microscale environmental variability in extreme arid conditions and lichen biodiversity patterns, we conducted the present study. For this purpose, the structure and distribution of lichen communities on soil and cobbles at six stations at "Evolution Canyon" III (EC III), Nahal Shaharut, in the extreme southern Negev, Israel, were examined. The opposite slopes of the canyon represented specific ecological niches characterized by sharply different microclimatic conditions. The following characteristics of lichen communities were studied: species richness, systematic diversity, biogeographical elements, frequencies and distribution of species, their morphological and anatomical characteristics, reproductive strategy, and ecological peculiarities. In the research site three environmental variables were evaluated: soil moisture, and temperatures of soil and cobbles. The Canonical Correspondence Analysis was used to study the influence of these ecological variables on the distribution of lichen species. The lichen diversity of EC III was very poor and comprised 12 species (3 cyanoliches on soil vs. 9 phycolichens on cobbles). Most of them belong to a specific group of arid endemic elements, adapted to survive in extreme arid conditions in the deserts of the Levant. The harsh desert conditions of the canyon negatively influence the reproductive ability of lichens. This influence is expressed in the decreased sizes of fruit bodies in some species, and the frequent occurrence of sterile specimens among lichens found in the canyon. A comparative analysis of structure

  19. How desert varnish forms?

    Science.gov (United States)

    Perry, Randall S.; Kolb, Vera M.; Lynne, Bridget Y.; Sephton, Mark A.; Mcloughlin, Nicola; Engel, Michael H.; Olendzenski, Lorraine; Brasier, Martin; Staley, James T., Jr.

    2005-09-01

    Desert varnish is a black, manganese-rich rock coating that is widespread on Earth. The mechanism underlying its formation, however, has remained unresolved. We present here new data and an associated model for how desert varnish forms, which substantively challenges previously accepted models. We tested both inorganic processes (e.g. clays and oxides cementing coatings) and microbial methods of formation. Techniques used in this preliminary study include SEM-EDAX with backscatter, HRTEM of focused ion beam prepared (FIB) wafers and several other methods including XRPD, Raman spectroscopy, XPS and Tof-SIMS. The only hypothesis capable of explaining a high water content, the presence of organic compounds, an amorphous silica phase (opal-A) and lesser quantities of clays than previously reported, is a mechanism involving the mobilization and redistribution of silica. The discovery of silica in desert varnish suggests labile organics are preserved by interaction with condensing silicic acid. Organisms are not needed for desert varnish formation but Bacteria, Archaea, Eukarya, and other organic compounds are passively incorporated and preserved as organominerals. The rock coatings thus provide useful records of past environments on Earth and possibly other planets. Additionally this model also helps to explain the origin of key varnish and rock glaze features, including their hardness, the nature of the "glue" that binds heterogeneous components together, its layered botryoidal morphology, and its slow rate of formation.

  20. High Levels of Antibiotic Resistance but No Antibiotic Production Detected Along a Gypsum Gradient in Great Onyx Cave, KY, USA

    Directory of Open Access Journals (Sweden)

    Kathleen Lavoie

    2017-09-01

    Full Text Available A preliminary study of antibiotic production and antibiotic resistance was conducted in Great Onyx Cave in Mammoth Cave National Park, KY, to determine if gypsum (CaSO4∙2H2O affects these bacterial activities. The cave crosses through the width of Flint Ridge, and passages under the sandstone caprock are dry with different amounts of gypsum. The Great Kentucky Desert hypothesis posits that gypsum limits the distribution of invertebrates in the central areas of Great Onyx Cave. Twenty-four bacterial isolates were cultivated from swabs and soils. Using three methods (soil crumb, soil crumb with indicator bacteria, and the cross-streak method using isolated bacteria we did not detect any production of antibiotics. Antibiotic resistance was widespread, with all 24 isolates resistant to a minimum of two antibiotics of seven tested, with three isolates resistant to all. Antibiotic resistance was high and not correlated with depth into the cave or the amount of gypsum. The Great Kentucky Desert hypothesis of the negative effects of gypsum seems to have no impact on bacterial activity.

  1. Gopherus agassizii (Desert Tortoise). Non-native seed dispersal

    Science.gov (United States)

    Ennen, J.R.; Loughran, Caleb L.; Lovich, Jeffrey E.

    2011-01-01

    Sahara Mustard (Brassica tournefortii) is a non-native, highly invasive weed species of southwestern U.S. deserts. Sahara Mustard is a hardy species, which flourishes under many conditions including drought and in both disturbed and undisturbed habitats (West and Nabhan 2002. In B. Tellman [ed.], Invasive Plants: Their Occurrence and Possible Impact on the Central Gulf Coast of Sonora and the Midriff Islands in the Sea of Cortes, pp. 91–111. University of Arizona Press, Tucson). Because of this species’ ability to thrive in these habitats, B. tournefortii has been able to propagate throughout the southwestern United States establishing itself in the Mojave and Sonoran Deserts in Arizona, California, Nevada, and Utah. Unfortunately, naturally disturbed areas created by native species, such as the Desert Tortoise (Gopherus agassizii), within these deserts could have facilitated the propagation of B. tournefortii. (Lovich 1998. In R. G. Westbrooks [ed.], Invasive Plants, Changing the Landscape of America: Fact Book, p. 77. Federal Interagency Committee for the Management of Noxious and Exotic Weeds [FICMNEW], Washington, DC). However, Desert Tortoises have never been directly observed dispersing Sahara Mustard seeds. Here we present observations of two Desert Tortoises dispersing Sahara Mustard seeds at the interface between the Mojave and Sonoran deserts in California.

  2. Fog water chemistry in the Namib desert, Namibia

    Science.gov (United States)

    Eckardt, Frank D.; Schemenauer, Robert S.

    This study documents the ion concentrations and ion enrichment relative to sea water, in Namib Desert fog water, with the purpose of establishing its suitability for future fogwater collection schemes, while also examining claims that Namib Desert fog water carries exceptionally high concentrations of sulphate, which may be responsible for the formation of gypsum deposits in the desert. The work suggests that Namibian fog water is at least as clean as has been reported from other coastal deserts in South America and Arabia, and provides a source of very clean water for the coastal desert region of south-western Africa. It does not appear that fog is an efficient sulphur source for the formation of the gypsum deposits, unless rare events with high concentrations of marine sulphur compounds occur.

  3. Bringing the Great American Solar Eclipse to West Virginia

    Science.gov (United States)

    Keesee, A. M.; Williamson, K.; Robertson-Honecker, J.

    2017-12-01

    West Virginia experienced up to 90% coverage during the Great American Solar Eclipse on August 21st. To reach the greatest number of West Virginians, we targeted educators and the 4-H program to provide those community leaders with the tools to help students learn about and safely view the eclipse. We developed a website that consolodated relevant eclipse activities, fact sheets, and outreach videos to train educators and others in the public about the science of the eclipse and how to view a partial eclipse safely. The 4-H Summer Experiement used at all 4-H summer camps and events was designed to focus on the eclipse. We distributed over 20,000 custom designed eclipse glasses. These were distributed to teachers through an online request system and to 4-H members involved in summer activities. We hosted a pre-eclipse event on the campus of West Virginia University for the public to learn about the science of the eclipse, relevant research being conducted at the university, and provide tips for safe viewing. Student volunteers were available on campus during the day of the eclipse to hand out glasses and answer questions. We will present the results of our outreach and events as well as lessons learned for the 2024 eclipse. Support for this project was provided by the WVU Department of Physics and Astronomy, WVU Extension, the WV Space Grant Consortium, a WVU internal grant, the Green Bank Observatory, and individual supporters of a crowdfunding campaign.

  4. Nationwide desert highway assessment: a case study in China.

    Science.gov (United States)

    Mao, Xuesong; Wang, Fuchun; Wang, Binggang

    2011-07-01

    The natural environment affects the construction of desert highways. Conversely, highway construction affects the natural environment and puts the ecological environment at a disadvantage. To satisfy the variety and hierarchy of desert highway construction and discover the spatio-temporal distribution of the natural environment and its effect on highway construction engineering, an assessment of the natural regional divisions of desert highways in China is carried out for the first time. Based on the general principles and method for the natural region division, the principles, method and index system for desert highway assessment is put forward by combining the desert highway construction features and the azonal differentiation law. The index system combines the dominant indicator and four auxiliary indicators. The dominant indicator is defined by the desert's comprehensive state index and the auxiliary indicators include the sand dune height, the blown sand strength, the vegetation coverage ratio and the annual average temperature difference. First the region is divided according to the dominant indicator. Then the region boundaries are amended according to the four auxiliary indicators. Finally the natural region division map for desert highway assessment is presented. The Chinese desert highways can be divided into three sections: the east medium effect region, the middle medium-severe effect region, and the west slight-medium effect region. The natural region division map effectively paves the way for the route planning, design, construction, maintenance and ongoing management of desert highways, and further helps environmental protection.

  5. In vitro germination of desert rose varieties(

    Directory of Open Access Journals (Sweden)

    Tatiane Lemos Varella

    2015-08-01

    Full Text Available The drought stress resistance is a characteristic of the desert rose and its estimable beauty flowers, which gave it great relevance in the ornamental market. However, the desert rose production and germination is hampered by possible sterility of their male and female flowers and frequent problems in pollination, so the tissue culture is a promising alternative to the propagation of these plants. This study aimed to evaluate the effect of gibberellic acid on four commercial varieties of desert rose (Adenium obesum cultivated in vitro. The seeds of the varieties ‘Orange Pallet’, ‘Carnation violet’, ‘Diamond ring’ and ‘Vermiliont’ were sterilized and inoculated on Water + Agar (T0, medium MS (T1, ½ MS (T2, MS + 0.25 mg L-1 GA3 (T3, MS + 0.5 mg L-1 GA3 (T4, ½ MS + 0.25 mg L-1 GA3 (T5, ½ MS 0.5 mg L-1 GA3 (T6. The seeds germination of A. obesum was initiated on the fourth day of cultivation and on the tenth day was possible to observe the expansion of the cotyledons and leaf expansion with subsequent development of early secondary root. The ‘Orange pallet’ variety germinated 100% of seeds on water + agar and MS ½ + 0.5 mg L-1 of GA3. For ‘Diamond Ring’ and ‘Carnation violet’ the highest rate of germination occurred in treatments MS ½; 0.25 mg L-1 GA3; MS + 0.5 mg L-1 GA3 MS ½ + 0.5 mg L-1 GA3 averaging 80% and 70%, respectively. For ‘Vermiliont’ the best response was in MS and MS ½ + 0.5 mg L-1 GA3 ranging between 70-90% germinated embryos. It was registered different malformations in all treatments like absence of roots and apexes during seedling development. The concentrations of GA3 did not affect significantly the seed germination.

  6. Desert Pavement Studies

    National Research Council Canada - National Science Library

    Haff, Peter

    2003-01-01

    Combining plan view information from aerial photography showing details of stream channels on desert pavement surfaces with process-based erosion models, a high-resolution, synthetic topography DEM...

  7. Desert Pavement Studies

    National Research Council Canada - National Science Library

    Haff, P

    2003-01-01

    Combining plan view information from aerial photography showing details of stream channels on desert pavement surfaces with process-based erosion models, a high-resolution, "synthetic topography" DEM...

  8. Remote Sensing Field Guide - Desert

    Science.gov (United States)

    1991-09-01

    experienced boatmen. Most river water, even in deserts, contains Giardia micro -organisms that can cause serious diarrhea. Sich water should be boiled...water. The solutes and suspended micro -matter can be moved up and down by an oscillating water table and redeposited or precipitated at differ- ent...McCauley, U.S. Geological Survey, Desert Studies Group, Flagstaff, AZ, Nov 1973. B. Servicio Aerofotografia Nacional del Peru (on back). / ...... CONN:MFI

  9. The Great Recession and confidence in homeownership

    OpenAIRE

    Anat Bracha; Julian Jamison

    2013-01-01

    Confidence in homeownership shifts for those who personally experienced real estate loss during the Great Recession. Older Americans are confident in the value of homeownership. Younger Americans are less confident.

  10. Reading the American Landscape. An Index of Books and Images

    NARCIS (Netherlands)

    Jong, de E.; Schreiber, H.; Sijmons, D.F.; Hoogewoning, A.

    2009-01-01

    From city high-rise to southern desert, from urban sprawl to virgin canyons, the American landscape is endless in its variety. On the initiative of the Netherlands Foundation for Visual Arts, Design and Architecture, a group of landscape architects, architects, urban designers, artists and critics

  11. The impact of desert solar power utilization on sustainable development

    International Nuclear Information System (INIS)

    Sadiq Ali Shah; Yang Zhang

    2011-01-01

    This paper evaluates the prospects of developing a solar based desert economy in the deserts of solar-rich countries. The potential deserts are analysed to study their positive impact on the sustainable development processes in these regions. The sustainability of the processes is established on the basis of self-contained nature of energy generation, environmental emission reduction and desert land reclamation. (authors)

  12. Microbial ecology of hot desert edaphic systems.

    Science.gov (United States)

    Makhalanyane, Thulani P; Valverde, Angel; Gunnigle, Eoin; Frossard, Aline; Ramond, Jean-Baptiste; Cowan, Don A

    2015-03-01

    A significant proportion of the Earth's surface is desert or in the process of desertification. The extreme environmental conditions that characterize these areas result in a surface that is essentially barren, with a limited range of higher plants and animals. Microbial communities are probably the dominant drivers of these systems, mediating key ecosystem processes. In this review, we examine the microbial communities of hot desert terrestrial biotopes (including soils, cryptic and refuge niches and plant-root-associated microbes) and the processes that govern their assembly. We also assess the possible effects of global climate change on hot desert microbial communities and the resulting feedback mechanisms. We conclude by discussing current gaps in our understanding of the microbiology of hot deserts and suggest fruitful avenues for future research. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Desert potholes: Ephemeral aquatic microsystems

    Science.gov (United States)

    Chan, M.A.; Moser, K.; Davis, J.M.; Southam, G.; Hughes, K.; Graham, T.

    2005-01-01

    An enigma of the Colorado Plateau high desert is the "pothole", which ranges from shallow ephemeral puddles to deeply carved pools. The existence of prokaryotic to eukaryotic organisms within these pools is largely controlled by the presence of collected rainwater. Multivariate statistical analysis of physical and chemical limnologic data variables measured from potholes indicates spatial and temporal variations, particularly in water depth, manganese, iron, nitrate and sulfate concentrations and salinity. Variation in water depth and salinity are likely related to the amount of time since the last precipitation, whereas the other variables may be related to redox potential. The spatial and temporal variations in water chemistry affect the distribution of organisms, which must adapt to daily and seasonal extremes of fluctuating temperature (0-60 ??C), pH changes of as much as 5 units over 12 days, and desiccation. For example, many species become dormant when potholes dry, in order to endure intense heat, UV radiation, desiccation and freezing, only to flourish again upon rehydration. But the pothole organisms also have a profound impact on the potholes. Through photosynthesis and respiration, pothole organisms affect redox potential, and indirectly alter the water chemistry. Laboratory examination of dried biofilm from the potholes revealed that within 2 weeks of hydration, the surface of the desiccated, black biofilm became green from cyanobacterial growth, which supported significant growth in heterotrophic bacterial populations. This complex biofilm is persumably responsible for dissolving the cement between the sandstone grains, allowing the potholes to enlarge, and for sealing the potholes, enabling them to retain water longer than the surrounding sandstone. Despite the remarkable ability of life in potholes to persist, desert potholes may be extremely sensitive to anthropogenic effects. The unique limnology and ecology of Utah potholes holds great scientific

  14. Food swamps and food deserts in Baltimore City, MD, USA: associations with dietary behaviours among urban adolescent girls.

    Science.gov (United States)

    Hager, Erin R; Cockerham, Alexandra; O'Reilly, Nicole; Harrington, Donna; Harding, James; Hurley, Kristen M; Black, Maureen M

    2017-10-01

    To determine whether living in a food swamp (≥4 corner stores within 0·40 km (0·25 miles) of home) or a food desert (generally, no supermarket or access to healthy foods) is associated with consumption of snacks/desserts or fruits/vegetables, and if neighbourhood-level socio-economic status (SES) confounds relationships. Cross-sectional. Assessments included diet (Youth/Adolescent FFQ, skewed dietary variables normalized) and measured height/weight (BMI-for-age percentiles/Z-scores calculated). A geographic information system geocoded home addresses and mapped food deserts/food swamps. Associations examined using multiple linear regression (MLR) models adjusting for age and BMI-for-age Z-score. Baltimore City, MD, USA. Early adolescent girls (6th/7th grade, n 634; mean age 12·1 years; 90·7 % African American; 52·4 % overweight/obese), recruited from twenty-two urban, low-income schools. Girls' consumption of fruit, vegetables and snacks/desserts: 1·2, 1·7 and 3·4 servings/d, respectively. Girls' food environment: 10·4 % food desert only, 19·1 % food swamp only, 16·1 % both food desert/swamp and 54·4 % neither food desert/swamp. Average median neighbourhood-level household income: $US 35 298. In MLR models, girls living in both food deserts/swamps consumed additional servings of snacks/desserts v. girls living in neither (β=0·13, P=0·029; 3·8 v. 3·2 servings/d). Specifically, girls living in food swamps consumed more snacks/desserts than girls who did not (β=0·16, P=0·003; 3·7 v. 3·1 servings/d), with no confounding effect of neighbourhood-level SES. No associations were identified with food deserts or consumption of fruits/vegetables. Early adolescent girls living in food swamps consumed more snacks/desserts than girls not living in food swamps. Dietary interventions should consider the built environment/food access when addressing adolescent dietary behaviours.

  15. Cinema and the Great War - Andrew Kelly, 1997. History by Hollywood. The use and abuse of the American past - Robert Brant Toplin, 1996

    NARCIS (Netherlands)

    Kester, Bernadette

    1998-01-01

    textabstractReview of: Cinema and the Great War. Andrew Kelly, Londen, New York (Routledge), 1997, 219 p.History by Hollywood. The use and abuse of the American past. Robert Brant Toplin, Chicago (Urbana), 1996, 267 p.

  16. Planetary Science from NASA's WB-57 Canberra High Altitude Research Aircraft During the Great American Eclipse of 2017

    Science.gov (United States)

    Tsang, C.; Caspi, A.; DeForest, C. E.; Durda, D. D.; Steffl, A.; Lewis, J.; Wiseman, J.; Collier, J.; Mallini, C.; Propp, T.; Warner, J.

    2017-12-01

    The Great American Eclipse of 2017 provided an excellent opportunity for heliophysics research on the solar corona and dynamics that encompassed a large number of research groups and projects, including projects flown in the air and in space. Two NASA WB-57F Canberra high altitude research aircraft were launched from NASA's Johnson Space Center, Ellington Field into the eclipse path. At an altitude of 50,000ft, and outfitted with visible and near-infrared cameras, these aircraft provided increased duration of observations during eclipse totality, and much sharper images than possible on the ground. Although the primary mission goal was to study heliophysics, planetary science was also conducted to observe the planet Mercury and to search for Vulcanoids. Mercury is extremely challenging to study from Earth. The 2017 eclipse provided a rare opportunity to observe Mercury under ideal astronomical conditions. Only a handful of near-IR thermal images of Mercury exist, but IR images provide critical surface property (composition, albedo, porosity) information, essential to interpreting lower resolution IR spectra. Critically, no thermal image of Mercury currently exists. By observing the nightside surface during the 2017 Great American Eclipse, we aimed to measure the diurnal temperature as a function of local time (longitude) and attempted to deduce the surface thermal inertia integrated down to a few-cm depth below the surface. Vulcanoids are a hypothesized family of asteroids left over from the formation of the solar system, in the dynamically stable orbits between the Sun and Mercury at 15-45 Rs (4-12° solar elongation). Close proximity to the Sun, plus their small theoretical sizes, make Vulcanoid searches rare and difficult. The 2017 eclipse was a rare opportunity to search for Vulcanoids. If discovered these unique, highly refractory and primordial bodies would have a significant impact on our understanding of solar system formation. Only a handful of deep

  17. Enhancing and restoring habitat for the desert tortoise

    Science.gov (United States)

    Abella, Scott R.; Berry, Kristin H.

    2016-01-01

    Habitat has changed unfavorably during the past 150 y for the desert tortoise Gopherus agassizii, a federally threatened species with declining populations in the Mojave Desert and western Sonoran Desert. To support recovery efforts, we synthesized published information on relationships of desert tortoises with three habitat features (cover sites, forage, and soil) and candidate management practices for improving these features for tortoises. In addition to their role in soil health and facilitating recruitment of annual forage plants, shrubs are used by desert tortoises for cover and as sites for burrows. Outplanting greenhouse-grown seedlings, protected from herbivory, has successfully restored (>50% survival) a variety of shrubs on disturbed desert soils. Additionally, salvaging and reapplying topsoil using effective techniques is among the more ecologically beneficial ways to initiate plant recovery after severe disturbance. Through differences in biochemical composition and digestibility, some plant species provide better-quality forage than others. Desert tortoises selectively forage on particular annual and herbaceous perennial species (e.g., legumes), and forage selection shifts during the year as different plants grow or mature. Nonnative grasses provide low-quality forage and contribute fuel to spreading wildfires, which damage or kill shrubs that tortoises use for cover. Maintaining a diverse “menu” of native annual forbs and decreasing nonnative grasses are priorities for restoring most desert tortoise habitats. Reducing herbivory by nonnative animals, carefully timing herbicide applications, and strategically augmenting annual forage plants via seeding show promise for improving tortoise forage quality. Roads, another disturbance, negatively affect habitat in numerous ways (e.g., compacting soil, altering hydrology). Techniques such as recontouring road berms to reestablish drainage patterns, vertical mulching (“planting” dead plant material

  18. Regional signatures of plant response to drought and elevated temperature across a desert ecosystem

    Science.gov (United States)

    Munson, Seth M.; Muldavin, Esteban H.; Belnap, Jayne; Peters, Debra P.C.; Anderson, John P.; Reiser, M. Hildegard; Gallo, Kirsten; Melgoza-Castillo, Alicia; Herrick, Jeffrey E.; Christiansen, Tim A.

    2013-01-01

    The performance of many desert plant species in North America may decline with the warmer and drier conditions predicted by climate change models, thereby accelerating land degradation and reducing ecosystem productivity. We paired repeat measurements of plant canopy cover with climate at multiple sites across the Chihuahuan Desert over the last century to determine which plant species and functional types may be the most sensitive to climate change. We found that the dominant perennial grass, Bouteloua eriopoda, and species richness had nonlinear responses to summer precipitation, decreasing more in dry summers than increasing with wet summers. Dominant shrub species responded differently to the seasonality of precipitation and drought, but winter precipitation best explained changes in the cover of woody vegetation in upland grasslands and may contribute to woody-plant encroachment that is widespread throughout the southwestern United States and northern Mexico. Temperature explained additional variability of changes in cover of dominant and subdominant plant species. Using a novel empirically based approach we identified ‘‘climate pivot points’’ that were indicative of shifts from increasing to decreasing plant cover over a range of climatic conditions. Reductions in cover of annual and several perennial plant species, in addition to declines in species richness below the long-term summer precipitation mean across plant communities, indicate a decrease in the productivity for all but the most drought-tolerant perennial grasses and shrubs in the Chihuahuan Desert. Overall, our regional synthesis of long-term data provides a robust foundation for forecasting future shifts in the composition and structure of plant assemblages in the largest North American warm desert.

  19. Growth responses of five desert plants as influenced by biological soil crusts from a temperate desert, China

    Science.gov (United States)

    Zhang, Yuanming; Belnap, Jayne

    2015-01-01

    In almost all dryland systems, biological soil crusts (biocrusts) coexist alongside herbaceous and woody vegetation, creating landscape mosaics of vegetated and biocrusted patches. Results from past studies on the interaction between biocrusts and vascular plants have been contradictory. In the Gurbantunggut desert, a large temperate desert in northwestern China, well-developed lichen-dominated crusts dominate the areas at the base and between the sand dunes. We examined the influence of these lichen-dominated biocrusts on the germination, growth, biomass accumulation, and elemental content of five common plants in this desert: two shrubs (Haloxylon persicum, Ephedra distachya) and three herbaceous plants (Ceratocarpus arenarius, Malcolmia africana and Lappula semiglabra) under greenhouse conditions. The influence of biocrusts on seed germination was species-specific. Biocrusts did not affect percent germination in plants with smooth seeds, but inhibited germination of seeds with appendages that reduced or eliminated contact with the soil surface or prevented seeds from slipping into soil cracks. Once seeds had germinated, biocrusts had different influences on growth of shrub and herbaceous plants. The presence of biocrusts increased concentrations of nitrogen but did not affect phosphorus or potassium in tissue of all tested species, while the uptake of the other tested nutrients was species-specific. Our study showed that biocrusts can serve as a biological filter during seed germination and also can influence growth and elemental uptake. Therefore, they may be an important trigger for determining desert plant diversity and community composition in deserts.

  20. The Use of Water During the Crew 144, Mars Desert Research Station, Utah Desert

    Science.gov (United States)

    De Morais Mendonca Teles, Antonio

    2016-07-01

    Well. from November 29th to December 14th, 2014, the author conducted astrobiological and geological surveys, as analog astronaut member of the international Crew 144, at the site of the Mars Society's Mars Desert Research Station, located at a remote location in the Utah desert, United States. The use of water for drinking, bathing, cleaning, etc., in the crew was a major issue for consideration for a human expedition to the planet Mars in the future. The author would like to tell about the factors of the rationalized use of water.

  1. Remote sensing of Sonoran Desert vegetation structure and phenology with ground-based LiDAR

    Science.gov (United States)

    Sankey, Joel B.; Munson, Seth M.; Webb, Robert H.; Wallace, Cynthia S.A.; Duran, Cesar M.

    2015-01-01

    Long-term vegetation monitoring efforts have become increasingly important for understanding ecosystem response to global change. Many traditional methods for monitoring can be infrequent and limited in scope. Ground-based LiDAR is one remote sensing method that offers a clear advancement to monitor vegetation dynamics at high spatial and temporal resolution. We determined the effectiveness of LiDAR to detect intra-annual variability in vegetation structure at a long-term Sonoran Desert monitoring plot dominated by cacti, deciduous and evergreen shrubs. Monthly repeat LiDAR scans of perennial plant canopies over the course of one year had high precision. LiDAR measurements of canopy height and area were accurate with respect to total station survey measurements of individual plants. We found an increase in the number of LiDAR vegetation returns following the wet North American Monsoon season. This intra-annual variability in vegetation structure detected by LiDAR was attributable to a drought deciduous shrub Ambrosia deltoidea, whereas the evergreen shrub Larrea tridentata and cactus Opuntia engelmannii had low variability. Benefits of using LiDAR over traditional methods to census desert plants are more rapid, consistent, and cost-effective data acquisition in a high-resolution, 3-dimensional context. We conclude that repeat LiDAR measurements can be an effective method for documenting ecosystem response to desert climatology and drought over short time intervals and at detailed-local spatial scale.

  2. A "Great Roads" Approach to Teaching Modern World History and Latin American Regional Survey Courses: A Veracruz to Mexico City Case Study.

    Science.gov (United States)

    Brown, James Seay, Jr.; Sullivan-Gonzalez, Douglass

    2002-01-01

    Outlines an innovative way of teaching "World History Since 1500" at Samford University (Birmingham, Alabama) called the "great roads" approach, centered upon important roads in a country's history. Presents the "Veracruz to Mexico City corridor" case study used to teach a Latin American modern history course. (CMK)

  3. Comparison of respiratory and growth characteristics of two co-occurring shrubs from a cold desert, Coleogyne ramosissima (blackbrush) and Atriplex confertifolia (shadscale)

    Science.gov (United States)

    H. A. Summers; B. N. Smith; L. D. Hansen

    2009-01-01

    Coleogyne ramosissima Torr. (blackbrush) and Atriplex confertifolia [Torr. & Frem.] Wats. (shadscale) are cold desert shrubs from different families. Despite very different life histories they often grow in close geographic proximity in the Great Basin and the Colorado Plateau between 800 and 2000 m elevation. The purpose of...

  4. Second-Generation Outcomes of the Great Migration.

    Science.gov (United States)

    Alexander, J Trent; Leibbrand, Christine; Massey, Catherine; Tolnay, Stewart

    2017-12-01

    The mass migration of African Americans out of the South during the first two-thirds of the twentieth century represents one of the most significant internal migration flows in U.S. Those undertaking the Great Migration left the South in search of a better life, and their move transformed the cultural, social, and political dynamics of African American life specifically and U.S. society more generally. Recent research offers conflicting evidence regarding the migrants' success in translating their geographic mobility into economic mobility. Due in part to the lack of a large body of longitudinal data, almost all studies of the Great Migration have focused on the migrants themselves, usually over short periods of their working lives. Using longitudinally linked census data, we take a broader view, investigating the long-term economic and social effects of the Great Migration on the migrants' children. Our results reveal modest but statistically significant advantages in education, income, and poverty status for the African American children of the Great Migration relative to the children of southerners who remained in the South. In contrast, second-generation white migrants experienced few benefits from migrating relative to southern or northern stayers.

  5. Herpetology of the American Madrean Archipelago and adjacent valleys

    Science.gov (United States)

    Lawrence L. C. Jones

    2005-01-01

    Approximately 110 species of amphibians (18 frogs and toads, and 1 salamander) and reptiles (47 snakes, 39 lizards, and 5 turtles) are known from the American Madrean Archipelago and adjacent valleys. The high diversity of the herpetofauna comes from a variety of factors, including a convergence of biotic communities representing deserts, grasslands, and mountains....

  6. [Fractal features of soil particle size in the process of desertification in desert grassland of Ningxia, China].

    Science.gov (United States)

    Yan, Xin; An, Hui

    2017-10-01

    The variation of soil properties, the fractal dimension of soil particle size, and the relationships between fractal dimension of soil particle size and soil properties in the process of desertification in desert grassland of Ningxia were discussed. The results showed that the fractal dimension (D) at different desertification stages in desert grassland varied greatly, the value of D was between 1.69 and 2.62. Except for the 10-20 cm soil layer, the value of D gradually declined with increa sing desertification of desert grassland at 0-30 cm soil layer. In the process of desertification in de-sert grassland, the grassland had the highest values of D , the volume percentage of clay and silt, and the lowest values of the volume percentage of very fine sand and fine sand. However, the mobile dunes had the lowest value of D , the volume percentage of clay and silt, and the highest value of the volume percentage of very fine sand and fine sand. There was a significant positive correlation between the soil fractal dimension value and the volume percentage of soil particles 50 μm. The grain size of 50 μm was the critical value for deciding the relationship between the soil particle fractal dimension and the volume percentage. Soil organic matter (SOM) and total nitrogen (TN) decreased gradually with increasing desertification of desert grassland, but soil bulk density increased gradually. Qualitative change from fixed dunes to semi fixed dunes with the rapid decrease of the volume percentage of clay and silt, SOM, TN and the rapid increase of volume percentage of very fine sand and fine sand, soil bulk density. Fractal dimension was significantly correlated to SOM, TN and soil bulk density. Fractal dimension 2.58 was a critical value of fixed dunes and semi fixed dunes. So, the fractal dimension of 2.58 could be taken as the desertification indicator of desert grassland.

  7. Desert Perennial Shrubs Shape the Microbial-Community Miscellany in Laimosphere and Phyllosphere Space.

    Science.gov (United States)

    Martirosyan, Varsik; Unc, Adrian; Miller, Gad; Doniger, Tirza; Wachtel, Chaim; Steinberger, Yosef

    2016-10-01

    Microbial function, composition, and distribution play a fundamental role in ecosystem ecology. The interaction between desert plants and their associated microbes is expected to greatly affect their response to changes in this harsh environment. Using comparative analyses, we studied the impact of three desert shrubs, Atriplex halimus (A), Artemisia herba-alba (AHA), and Hammada scoparia (HS), on soil- and leaf-associated microbial communities. DNA extracted from the leaf surface and soil samples collected beneath the shrubs were used to study associated microbial diversity using a sequencing survey of variable regions of bacterial 16S rRNA and fungal ribosomal internal transcribed spacer (ITS1). We found that the composition of bacterial and fungal orders is plant-type-specific, indicating that each plant type provides a suitable and unique microenvironment. The different adaptive ecophysiological properties of the three plant species and the differential effect on their associated microbial composition point to the role of adaptation in the shaping of microbial diversity. Overall, our findings suggest a link between plant ecophysiological adaptation as a "temporary host" and the biotic-community parameters in extreme xeric environments.

  8. Parental Attachment, Self-Esteem, and Antisocial Behaviors among African American, European American, and Mexican American Adolescents.

    Science.gov (United States)

    Arbona, Consuelo; Power, Thomas G.

    2003-01-01

    Examines the relation of mother and father attachment to self-esteem and self-reported involvement in antisocial behaviors among African American, European American, and Mexican American high school students. Findings indicated that adolescents from the 3 ethnic/racial groups did not differ greatly in their reported attachment. (Contains 70…

  9. Plantation Development in the Turkana Basin: The Making of a New Desert?

    Directory of Open Access Journals (Sweden)

    Edward G. J. Stevenson

    2018-01-01

    Full Text Available Since the early 20th century, “desert reclamation” has been synonymous with large-scale waterworks and irrigation. These techniques have made it possible to produce abundant crops in arid or semi-arid environments. The costs have often been externalized, with increased environmental productivity in the new croplands counterbalanced by increased aridity elsewhere. In this paper I consider whose interests are served by such projects, and what kinds of social constructions of the natural and human environment make them possible. I focus on the Turkana basin, a watershed spanning the Ethiopian and Kenyan borders, where large dams and irrigation projects are currently being established with the goal of producing cash crops and hydro-electricity. In the narratives of the projects’ proponents, the schemes are represented as part of a tradition of development stretching back to the American West. In the discourse of critics, the Aral Sea of Central Asia is frequently invoked. Considering Turkana in relation to these cases sheds light on the political and ecological gambits involved in desert reclamation, and helps us to understand the costs and benefits of such projects.

  10. Oxalosis in wild desert tortoises, Gopherus agassizii

    Science.gov (United States)

    Jacobson, Elliott R.; Berry, Kristin H.; Stacy, Brian; Huzella, Louis M.; Kalasinsky, Victor F.; Fleetwood, Michelle L.; Mense, Mark G.

    2009-01-01

    We necropsied a moribund, wild adult male desert tortoise (Gopherus agassizii) with clinical signs of respiratory disease and elevated plasma biochemical analytes indicative of renal disease (blood urea nitrogen [415 mg/dl], uric acid [11.8 mg/dl], sodium >180 mmol/l] and chloride [139 mmol/l]). Moderate numbers of birefringent oxalate crystals, based on infrared and electron microscopy, were present within renal tubules; small numbers were seen in colloid within thyroid follicles. A retrospective analysis of 66 additional cases of wild desert tortoises was conducted to determine whether similar crystals were present in thyroid and kidney. The tortoises, from the Mojave and Sonoran deserts, were necropsied between 1992 and 2003 and included juveniles and adults. Tortoises were classified as healthy (those that died due to trauma and where no disease was identified after necropsy and evaluation by standard laboratory tests used for other tortoises) or not healthy (having one or more diseases or lesions). For all 67 necropsied tortoises, small numbers of crystals of similar appearance were present in thyroid glands from 44 of 54 cases (81%) and in kidneys from three of 65 cases (5%). Presence of oxalates did not differ significantly between healthy and unhealthy tortoises, between age classes, or between desert region, and their presence was considered an incidental finding. Small numbers of oxalate crystals seen within the kidney of two additional tortoises also were considered an incidental finding. Although the source of the calcium oxalate could not be determined, desert tortoises are herbivores, and a plant origin seems most likely. Studies are needed to evaluate the oxalate content of plants consumed by desert tortoises, and particularly those in the area where the tortoise in renal failure was found.

  11. Long-Term Observations of Dust Storms in Sandy Desert Environments

    Science.gov (United States)

    Yun, Hye-Won; Kim, Jung-Rack; Choi, Yun-Soo

    2015-04-01

    Mineral dust occupies the largest portion of atmospheric aerosol. Considering the numerous risks that dust poses for socioeconomic and anthropogenic activities, it is crucial to understand sandy desert environments, which frequently generate dust storms and act as a primary source of atmospheric aerosol. To identify mineral aerosol mechanisms, it is essential to monitor desert environmental factors involving dust storm generation in the long term. In this study, we focused on two major environmental factors: local surface roughness and soil moisture. Since installments of ground observation networks in sandy deserts are unfeasible, remote sensing techniques for mining desert environmental factors were employed. The test area was established within the Badain Jaran and Kubuqi Deserts in Inner Mongolia, China, where significant seasonal aeolian processes emit mineral dust that influences all of East Asia. To trace local surface roughness, we employed a multi-angle imaging spectroradiometer (MISR) image sequence to extract multi-angle viewing (MAV) topographic parameters such as normalized difference angular index, which represents characteristics of the target desert topography. The backscattering coefficient from various space-borne SAR and stereotopography were compared with MAV observations to determine calibrated local surface roughness. Soil moisture extraction techniques from InSAR-phase coherence stacks were developed and compiled with advanced scatterometer (ASCAT) soil moisture data. Combined with metrological information such as the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA interim, correlations between intensity of sand dune activity as a proxy of aeolian processes in desert environments, surface wind conditions, and surface soil moisture were traced. Overall, we have confirmed that tracking sandy desert aeolian environments for long-term observations is feasible with space-borne, multi-sensor observations when combined with

  12. Genomic characterization of Ensifer aridi, a proposed new species of nitrogen-fixing rhizobium recovered from Asian, African and American deserts.

    Science.gov (United States)

    Le Quéré, Antoine; Tak, Nisha; Gehlot, Hukam Singh; Lavire, Celine; Meyer, Thibault; Chapulliot, David; Rathi, Sonam; Sakrouhi, Ilham; Rocha, Guadalupe; Rohmer, Marine; Severac, Dany; Filali-Maltouf, Abdelkarim; Munive, Jose-Antonio

    2017-01-14

    Nitrogen fixing bacteria isolated from hot arid areas in Asia, Africa and America but from diverse leguminous plants have been recently identified as belonging to a possible new species of Ensifer (Sinorhizobium). In this study, 6 strains belonging to this new clade were compared with Ensifer species at the genome-wide level. Their capacities to utilize various carbon sources and to establish a symbiotic interaction with several leguminous plants were examined. Draft genomes of selected strains isolated from Morocco (Merzouga desert), Mexico (Baja California) as well as from India (Thar desert) were produced. Genome based species delineation tools demonstrated that they belong to a new species of Ensifer. Comparison of its core genome with those of E. meliloti, E. medicae and E. fredii enabled the identification of a species conserved gene set. Predicted functions of associated proteins and pathway reconstruction revealed notably the presence of transport systems for octopine/nopaline and inositol phosphates. Phenotypic characterization of this new desert rhizobium species showed that it was capable to utilize malonate, to grow at 48 °C or under high pH while NaCl tolerance levels were comparable to other Ensifer species. Analysis of accessory genomes and plasmid profiling demonstrated the presence of large plasmids that varied in size from strain to strain. As symbiotic functions were found in the accessory genomes, the differences in symbiotic interactions between strains may be well related to the difference in plasmid content that could explain the different legumes with which they can develop the symbiosis. The genomic analysis performed here confirms that the selected rhizobial strains isolated from desert regions in three continents belong to a new species. As until now only recovered from such harsh environment, we propose to name it Ensifer aridi. The presented genomic data offers a good basis to explore adaptations and functionalities that enable them

  13. Goods and services provided by native plants in desert ecosystems: Examples from the northwestern coastal desert of Egypt

    Directory of Open Access Journals (Sweden)

    Laila M. Bidak

    2015-01-01

    Full Text Available About one third of the earth’s land surface is covered by deserts that have low and variable rainfall, nutrient-poor soils, and little vegetation cover. Here, we focus on the goods and services offered by desert ecosystems using the northwestern coastal desert of Egypt extending from Burg El-Arab to El-Salloum as an example. We conducted field surveys and collected other data to identify the goods services and provided by native plant species. A total of 322 native plant species were compiled. The direct services provided by these native plants included sources of food, medicine, and energy; indirect vegetation services included promotion of biodiversity, water storage, and soil fertility. The plant diversity in this ecosystem provided economic service benefits, such as sources of fodder, fuel-wood, and traditional medicinal plants. Changes in land use and recent ill-managed human activities may influence the availability of these services and strongly impact biodiversity and habitat availability. Although deserts are fragile and support low levels of productivity, they provide a variety of goods and services whose continuing availability is contingent upon the adoption of rational land management practices.

  14. Aborigines of the nuclear desert

    International Nuclear Information System (INIS)

    Rujula, A. de

    1985-01-01

    The chart of 'stable nuclides' extends from Hydrogen, to Z proportional 98, A proportional 263. It contains another island of stability - neutron stars - in a narrow range around Z proportional 10 56 , A proportional 10 57 . In between lies a supposedly barren region encompassing more than 50 orders of magnitude. This desert may be populated by strange quark balls: Stable single bags containing similar proportions of u, d and s quarks. These balls are candidates for the constituency of the 'dark mass' in galaxies and in the Universe. We describe seven ways to search for these possible inhabitants of the nuclear desert. (orig.)

  15. Severe acute dehydration in a desert rodent elicits a transcriptional response that effectively prevents kidney injury.

    Science.gov (United States)

    MacManes, Matthew David

    2017-08-01

    Animals living in desert environments are forced to survive despite severe heat, intense solar radiation, and both acute and chronic dehydration. These animals have evolved phenotypes that effectively address these environmental stressors. To begin to understand the ways in which the desert-adapted rodent Peromyscus eremicus survives, reproductively mature adults were subjected to 72 h of water deprivation, during which they lost, on average, 23% of their body weight. The animals reacted via a series of changes in the kidney, which included modulating expression of genes responsible for reducing the rate of transcription and maintaining water and salt balance. Extracellular matrix turnover appeared to be decreased, and apoptosis was limited. In contrast to the canonical human response, serum creatinine and other biomarkers of kidney injury were not elevated, suggesting that changes in gene expression related to acute dehydration may effectively prohibit widespread kidney damage in the cactus mouse. Copyright © 2017 the American Physiological Society.

  16. Parasites of freshwater fishes and the Great American Biotic Interchange: a bridge too far?

    Science.gov (United States)

    Choudhury, A; García-Varela, M; Pérez-Ponce de León, G

    2017-03-01

    We examine the extent to which adult helminths of freshwater fishes have been part of the Great American Biotic Interchange (GABI), by integrating information in published studies and new data from Panama with fish biogeography and Earth history of Middle America. The review illustrates the following: (1) the helminth fauna south of the Trans-Mexican Volcanic Belt, and especially south of the Isthmus of Tehuantepec, shows strong Neotropical affinities; (2) host-parasite associations follow principles of the 'biogeographic core fauna' in which host-lineage specificity is pronounced; (3) phylogenetic analysis of the widespread freshwater trematode family Allocreadiidae reveals a complex history of host-shifting and co-diversification involving mainly cyprinodontiforms and characids; (4) allocreadiids, monogeneans and spiruridan nematodes of Middle American cyprinodontiforms may provide clues to the evolutionary history of their hosts; and (5) phylogenetic analyses of cryptogonimid trematodes may reveal whether or how cichlids interacted with marine or brackish-water environments during their colonization history. The review shows that 'interchange' is limited and asymmetrical, but simple narratives of northward isthmian dispersal will likely prove inadequate to explain the historical biogeography of many host-parasite associations in tropical Middle America, particularly those involving poeciliids. Finally, our study highlights the urgent need for targeted survey work across Middle America, focused sampling in river drainages of Colombia and Venezuela, and deeper strategic sampling in other parts of South America, in order to develop and test robust hypotheses about fish-parasite associations in Middle America.

  17. Novel green algal isolates from the Egyptian hyper-arid desert oases: a polyphasic approach with a description of Pharao desertorum gen. et sp. nov. (Chlorophyceae, Chlorophyta).

    Science.gov (United States)

    Saber, Abdullah A; Fučíková, Karolina; McManus, Hilary A; Guella, Graziano; Cantonati, Marco

    2018-03-30

    The biodiversity of terrestrial algae is still grossly understudied, and African deserts in particular are barely touched in this respect. Here, four coccoid green algae from oases in the Western Desert of Egypt were characterized using a combination of morphotaxonomic, ecological and 18S rDNA data, with additional carotenoid and lipid analyses for two of the strains. Three strains were identified as affiliated with known taxa: Mychonastes sp., Asterarcys sp. (first report of this genus from a desert soil), and Stichococcus cf. deasonii. The fourth strain is proposed to represent a new cryptic genus Pharao gen. nov., with the type species P. desertorum sp. nov. The new taxon is sister to the clade of uncharacterized North American desert strains of Radiococcaceae (Chlorophyceae, Chlorophyta). The pigment profile of P. desertorum gen. et sp. nov. revealed carotenoids and chlorophylls typical of green algae. Bioorganic analysis showed a complex lipidome based on phospho- (PC), galacto- (MGDG and DGDG), betaine- (DGTS), and sulfoquinovosyl- (SQDG) membrane lipids, besides significant amounts of storage neutral lipids such as diacyl- (DAG) and triacylglycerols (TAG). The presence of saturated alkyl chains within all the membrane lipid classes in P. desertorum and Asterarcys sp. appears to reflect the need to maintain membrane fluidity and viscosity. In summary, African deserts likely still harbor new taxa to be described, and lipidomic analyses of such taxa may provide clues about their ability to survive in the extremely harsh desert habitats. © 2018 Phycological Society of America.

  18. [Stem sap flow and water consumption of Tamarix ramosissima in hinterland of Taklimakan Desert].

    Science.gov (United States)

    Xu, Hao; Zhang, Xi-Ming; Yan, Hai-Long; Yao, Shi-Jun

    2007-04-01

    From April to November 2005, the stem sap flow and water consumption of Tamarix ramosissima in the hinterland of Taklimakan Desert was measured by Flow-32 System. The results showed that, in the extremely arid hinterland of Taklimakan Desert and under enough water supply, the average daily water consumption of T. ramosissima with a stem diameter of 3.5 cm and 2.0 cm was 6.322 kg and 1.179 kg, respectively in one growth season. The stem sap flow of T. ramosissima presented a single-peaked curve, with an obvious day and night variation rhythm and fluctuated with environment factors. Under enough water supply, the environmenal factors such as total radiation, wind speed and air temperature were the main factors affecting the stem sap flow, and the dynamics of stem sap flow could be predicted by the liner regression model based on total radiation and wind speed. Because of the extremely arid environment and enough water supply, T. ramosissima had a relatively higher stem sap flow rate and a great water consumption.

  19. Summer watering patterns of mule deer in the Great Basin Desert, USA: implications of differential use by individuals and the sexes for management of water resources.

    Science.gov (United States)

    Shields, Andrew V; Larsen, Randy T; Whiting, Jericho C

    2012-01-01

    Changes in the abundance and distribution of free water can negatively influence wildlife in arid regions. Free water is considered a limiting factor for mule deer (Odocoileus hemionus) in the Great Basin Desert. Consequently, a better understanding of differential use of water by individuals and the sexes could influence the conservation and management of mule deer and water resources in their habitats. We deployed remote cameras at all known water sources (13 wildlife water developments and 4 springs) on one mountain range in western Utah, USA, during summer from 2007 to 2011 to document frequency and timing of water use, number of water sources used by males and females, and to estimate population size from individually identified mule deer. Male and female mule deer used different water sources but visited that resource at similar frequencies. Individual mule deer used few water sources and exhibited high fidelity to that resource. Wildlife water developments were frequently used by both sexes. Our results highlight the differing use of water sources by sexes and individual mule deer. This information will help guide managers when siting and reprovisioning wildlife water developments meant to benefit mule deer and will contribute to the conservation and management of this species.

  20. Summer Watering Patterns of Mule Deer in the Great Basin Desert, USA: Implications of Differential Use by Individuals and the Sexes for Management of Water Resources

    Directory of Open Access Journals (Sweden)

    Andrew V. Shields

    2012-01-01

    Full Text Available Changes in the abundance and distribution of free water can negatively influence wildlife in arid regions. Free water is considered a limiting factor for mule deer (Odocoileus hemionus in the Great Basin Desert. Consequently, a better understanding of differential use of water by individuals and the sexes could influence the conservation and management of mule deer and water resources in their habitats. We deployed remote cameras at all known water sources (13 wildlife water developments and 4 springs on one mountain range in western Utah, USA, during summer from 2007 to 2011 to document frequency and timing of water use, number of water sources used by males and females, and to estimate population size from individually identified mule deer. Male and female mule deer used different water sources but visited that resource at similar frequencies. Individual mule deer used few water sources and exhibited high fidelity to that resource. Wildlife water developments were frequently used by both sexes. Our results highlight the differing use of water sources by sexes and individual mule deer. This information will help guide managers when siting and reprovisioning wildlife water developments meant to benefit mule deer and will contribute to the conservation and management of this species.

  1. Disillusionment of the American Dream——On An American Tragedy

    Institute of Scientific and Technical Information of China (English)

    管秀丽

    2008-01-01

    Theodore Dreiser is now regarded as one of the pre-eminent American realistic novelists of the first half of the twentieth century.an anatomist of the American Dream.In his great work An American Tragedy,Dreis- er exposes and criticizes mercilessly the corruption and black side of American society.The disillusionment of the American Dream is an important theme of the fiction.This paper illustrates "An American Tragedy" is the re- flection of disillusionment of the American Dream in the perspectives of the tragedy of a mortal,the tragedy of American society,and the tragedy of the American Dream.

  2. Lizard burrows provide thermal refugia for larks in the Arabian desert

    NARCIS (Netherlands)

    Williams, JB; Tieleman, BI; Shobrak, M

    A common perception is that desert birds experience greater extremes of heat and aridity than their mammalian counterparts, in part, because birds do not use burrows as a refuge from the desert environment. We report observations of Dunn's Larks (Eremalauda dunni), Bar-tailed Desert Larks (Ammomanes

  3. Practicing for 2023 and 2024: What the AAS Solar Eclipse Task Force Learned from the "Great American Eclipse" of 2017

    Science.gov (United States)

    Fienberg, R. T.; Speck, A. K.; Habbal, S. R.

    2017-12-01

    More than three years ahead of the "Great American Eclipse" of August 2017, the American Astronomical Society formed the AAS Solar Eclipse Task Force to function as a think tank, coordinating body, and communication gateway to the vast resources available about the 2017 eclipse and solar eclipses more generally. The task force included professional and amateur astronomers, formal and informal educators, and science journalists; many had experienced total solar eclipses before, and others would experience their first totality in August 2017. The AAS task force secured funding from the AAS Council, the National Science Foundation, and NASA. These resources were used mainly for three purposes: (1) to build a website that contains basic information about solar eclipses, safe viewing practices, and eclipse imaging and video, along with resources for educators and the media and a searchable map of eclipse-related events and activities, with links to other authoritative websites with more detailed information; (2) to solicit, receive, evaluate, and fund proposals for mini-grants to support eclipse-related education and public outreach to underrepresented groups both inside and outside the path of totality; and (3) to organize a series of multidisciplinary workshops across the country to prepare communities for the eclipse and to facilitate collaborations between astronomers, meteorologists, school administrators, and transporation and emergency-management professionals. Most importantly, the AAS Solar Eclipse Task Force focused on developing and disseminating appropriate eclipse safety information. The AAS and NASA jointly developed safety messaging that won the endorsement of the American Academies of Opthalmology and Optometry. In the weeks immediately preceding the eclipse, it became clear that the marketplace was being flooded by counterfeit eclipse glasses and solar viewers, leading to a last minute change in our communication strategy. In this talk, we'll review the

  4. Partitioning of radiation and energy balance components in an inhomogeneous desert valley

    International Nuclear Information System (INIS)

    Malek, E.; Bingham, G.E.

    1997-01-01

    Radiation and energy balance components are required to validate global, regional, and local scale models representing surface heat flux relationships in the heterogeneous surfaces of the world's arid and desert regions. Research was conducted in north-eastern Nevada, U.S.A., in a Great Basin inhomogeneous semi-arid desert valley located at 40° 44′ N, 114° 26′ W, with an elevation of 1707 m above mean sea level, to study the daily, monthly, and annual mesoscale radiation and energy balance components. We established five radiation stations along with five Bowen ratio systems to measure the incoming (R si ) and outgoing (R so ) solar (shortwave) radiation, net (R n ) radiation, air temperatures and moisture at 1 and 2 m above-ground, the aggregated (soil + vegetation) surface temperature, soil heat flux at 8 cm (three locations at each station), soil temperatures at 2 and 6 cm above each soil flux plate, wind speed and direction at 10 m, and precipitation (if any) every 5 s averaged into 20 min throughout the valley during the 93–94 water year (beginning 1 October). Our study during the 93–94 water year showed that albedo (R so /R si ) ranged from 85% (snow-covered surface) to 10% (cloudy skies with wet surface) among stations. The water year total incoming solar radiation (averaged among stations) amounted to 6·33 × 10 3 MJ·m −2 and about 24% of that was reflected back to the atmosphere. The net longwave radiation (R ln = R lo − R li ) was about 32% of R si , where R lo and R li are the terrestrial (outgoing) and atmospheric (incoming) longwave radiation, respectively. The 93–94 water year average net radiation (R n ) among stations amounted to 2·68 × 10 3 MJ·m −2 (about 44% of R si ). Approximately 85·3% and 14·6% of R n were used for the processes of sensible (H) and latent (LE) heat fluxes, respectively. The annual R n contribution to surface soil heat flux (G surf ) was almost 0·1%. Monthly and annual relationships among

  5. AMERICAN DREAM: THE AMERICAN HEGEMONIC CULTURE AND ITS IMPLICATIONS TO THE WORLD

    Directory of Open Access Journals (Sweden)

    Kasiyarno .

    2014-02-01

    Full Text Available A nation could be a great one as long as it has a great dream. The best example for this is America. Through its long history, it manages to realize a dream to be a superpower. It can be said that “American Dream” is one of the most significant features for the growth of a “constantly eyeing for winner” culture. American Studies experts call it as a “hegemonic culture” in which American norms, values and cultural practices are considered superior against the world culture. Globalizing the culture has been the most effective engine to spread American cultural values and to shape the global civilizations. Using American Studies perspective, this paper attempts to review the extent to which the “American Dream” has successfully established Americanization, as well as how the hegemonic culture has influenced the lives of peoples across the world in the form of popular culture.

  6. The Great American Eclipse Glasses Debacle of 2017

    Science.gov (United States)

    Tresch Fienberg, Richard; AAS Solar Eclipse Task Force

    2018-01-01

    In 2014, looking ahead to the “Great American” solar eclipse of 21 August 2017, the American Astronomical Society established the AAS Solar Eclipse Task Force to help prepare the public for a safe and enjoyable experience. We worked with NASA and several associations of eye-care professionals to come up a safety message that we could all stand behind. The gist of it was that it is perfectly safe to view totality without protection, but when any part of the Sun’s bright face is exposed, you must view through eclipse glasses or handheld viewers that meet the ISO 12312-2 international safety standard for filters for direct viewing of the Sun. We compiled a list of manufacturers whose products we knew to meet the standard (because we examined their test data) and posted it on our website. These manufacturers were all based in the US or Europe. A few weeks before the eclipse, reports surfaced of viewers purchased on Amazon.com labeled “Made in China” or that were obvious knock-offs of US manufacturers’ products. Amazon responded by suspending virtually all sales of eclipse viewers and recalling many of units already sold and shipped. Millions of people who’d bought eclipse glasses online, whether from legitimate sources or from bad actors, were unsure whether they could trust their purchases. We had to change our safety messaging: it was no longer sufficient to tell people to look for the ISO 12312-2 label, because that was being printed on Chinese-made glasses that hadn’t actually been shown to meet the standard. Instead, the only way to know that you had safe viewers was to know that you got them from a legitimate source — which meant we had to expand the list on our website to include every legitimate seller we could identify. Doing so required a monumental effort under intense time pressure. Thankfully there were few reports of eye injuries following the eclipse, but apparently many people who otherwise would have viewed the eclipse chose to skip

  7. Population, desert expanding.

    Science.gov (United States)

    1992-01-01

    The conditions of desert expansion in the Sahara are highlighted. On the southern border the desert is growing at a rate of 3-6 miles/year. This growth is encroaching on arable land in Ethiopia and Mauritania. The region loses up to 28,000 sq miles/year of farmland. 33% of Africa's fertile land is threatened. Land-use patterns are responsible for the deterioration of the soil. Traditional practices are not effective because the practices are not suitable for permanent farming. Farmers also have stopped environmentally sound practices such as letting the fields remain fallow in order to renew soil fertility. Nomads overgraze areas before moving on. A recent study by the World Bank's Africa Region Office was released; the report details some of the links between rapid population growth, poor agricultural performance, and environmental degradation. Soil conditions are such that valuable topsoil is blow away by the wind because the layer is too thin. Vegetation at the desert's edge is used for cooking purposes or for heating fuel. Tropical and savannah areas are depleted when tree replacement is inadequate. Only 9 trees are planted for every 100 removed. The report emphasized the role of women and children in contributing to population pressure by increased fertility. Women's work load is heavy and children are a help in alleviating some of the burden of domestic and agricultural work. There is hope in meeting demographic, agricultural, food security, and environmental objectives over the next 30 years if the needs of women are met. The needs include access to education for young women, lessening the work loads of women, and decreasing child mortality through improved health care and access to safe water.

  8. Environmental racism: the US nuclear industry and native Americans

    International Nuclear Information System (INIS)

    Lehtinen, Ulla

    1997-01-01

    The author argues that the United States nuclear industry has acted in a discriminatory fashion towards Native American peoples and the land they hold as reservations. Both uranium mining and nuclear weapons testing is commonplace and plans now exist to locate a low-level radioactive waste dump in the Mojave desert in California, a sacred site for many native people. Opposition to such plans is growing among the Native Americans, sharpened by their existing commitment to conservation of the environment, but on their own, they are not a lobby powerful enough to oppose the might of the nuclear industry. (UK)

  9. Environmental racism: the US nuclear industry and native Americans

    Energy Technology Data Exchange (ETDEWEB)

    Lehtinen, Ulla [Organization of the Fourth World - First Peoples (Finland)

    1997-03-01

    The author argues that the United States nuclear industry has acted in a discriminatory fashion towards Native American peoples and the land they hold as reservations. Both uranium mining and nuclear weapons testing is commonplace and plans now exist to locate a low-level radioactive waste dump in the Mojave desert in California, a sacred site for many native people. Opposition to such plans is growing among the Native Americans, sharpened by their existing commitment to conservation of the environment, but on their own, they are not a lobby powerful enough to oppose the might of the nuclear industry. (UK).

  10. Deciphering the Role of Desert Dust in the Climate Puzzle: The Mediterranean Israeli Dust Experiment (MEIDEX)

    Science.gov (United States)

    Levin, Zev; Joseph, Joachim; Mekler, Yuri; Israelevich, Peter; Ganor, Eli; Hilsenrath, Ernest; Janz, Scott

    2002-01-01

    Numerous studies have shown that aerosol particles may be one of the primary agents that can offset the climate warming induced by the increase in the amount of atmospheric greenhouse gases. Desert aerosols are probably the most abundant and massive type of aerosol particles that are present in the atmosphere worldwide. These aerosols are carried over large distances and have various global impacts. They interact with clouds, impact the efficiency of their rain production and change their optical properties. They constitute one of the primary sources of minerals for oceanic life and influence the health of coral reefs. They have direct effects on human health, especially by inducing breathing difficulties in children. It was lately discovered that desert particles carry pathogens from the Sahara desert over the Atlantic Ocean, a fact that may explain the migration of certain types of diseases. Aerosols not only absorb solar radiation but also scatter it, so that their climatic effect is influenced not only by their physical properties and height distribution but also by the reflectivity of the underlying surface. This latter property changes greatly over land and is low over ocean surfaces. Aerosol plumes are emitted from discrete, sporadic sources in the desert areas of the world and are transported worldwide by the atmosphere's wind systems. For example, Saharan dust reaches Mexico City, Florida, Ireland, Switzerland and the Mediterranean region, while Asian dust reaches Alaska, Hawaii and the continental United States. This means that in order to assess its global effects, one must observe dust from space. The Space Shuttle is a unique platform, because it flies over the major deserts of our planet, enabling measurements and remote sensing of the aerosols as they travel from source to sink regions. Such efforts must always be accompanied by in-situ data for validation and calibration, with direct sampling of the airborne particles. MEIDEX is a joint project of

  11. Airborne particle accumulation and composition at different locations in the northern Negev desert.

    NARCIS (Netherlands)

    Offer, Z.Y.; Goossens, D.

    2001-01-01

    Atmospheric desert dust was collected over 36 months in ground-level collectors at four stations in the northern Negev desert, Israel. Three stations (Shivta, Sede Boqer and Avdat) are located in the desert itself whereas the fourth station (Sayeret Shaked) is situated at the desert fringe, in the

  12. The politics of accessing desert land in Jordan

    NARCIS (Netherlands)

    Naber, Al Majd; Molle, Francois

    2016-01-01

    With the dramatic increase of the population in Jordan, the value of land has rocketed up. Urban sprawl into semi-desert or desert areas, initially not surveyed or settled by the British and considered as state land, has brought to the surface the problematic status of those lands. Likewise, the

  13. J.M. Gratale on Tore T. Petersen’s Richard Nixon, Great Britain and the Anglo-American Alignment in the Persian Gulf and Arabian Peninsula

    Directory of Open Access Journals (Sweden)

    2009-09-01

    Full Text Available Tore T. Petersen. Richard Nixon, Great Britain and the Anglo-American Alignment in the Persian Gulf and Arabian Peninsula: Making Allies out of Clients. Sussex Academic Press, 2009.  172pp.  978-1-84519-277-8.Since the events of 9-11 there has been a sizeable quantity of books published on American foreign policy in broad terms, as well as more focused studies on contemporary developments in southwest Asia, more commonly referred to as the Middle East. Many of these volumes are highly politic...

  14. The Great American Divide: The Military-Civilian Gap

    Science.gov (United States)

    2012-03-14

    Steven A. Bank, Kirk J. Stark, and Joseph J. Thorndike provide a historical account of America’s war-time fiscal policies for the major American wars...accessed January 16, 2012). 63 Steven A. Bank, Kirk J. Stark, Joseph J. Thorndike , War and Taxes (Washington, DC: The Urban Institute Press, 2008

  15. An Integrated Multi-Sensor Approach to Monitor Desert Environments by UAV and Satellite Sensors: Case Study Kubuqi Desert, China

    Science.gov (United States)

    Kim, J.; Lin, C. W.; vanGasselt, S.; Lin, S.; Lan, C. W.

    2017-12-01

    Expanding deserts have been causing significant socio-economical threats by, e.g., hampering anthropogenic activities or causing decline of agricultural productivity. Countries in the Asian-Pacific regions in particular have been suffering from dust storms originating in the arid deserts of China, Mongolia and central Asia. In order to mitigate such environmental interferences by means of, e.g. combat desertification activities and early warning systems, the establishment of reliable desert monitoring schemes is needed. In this study, we report on a remote sensing data fusion approach to constantly and precisely monitor desert environments. We have applied this approach over a test site located in the Kubuqi desert located in Northeast China and which is considered to be a major contributor of dust storms today. In order to understand spatial and temporal trends of desertification, the planimetric distribution and 3D shape and size of sand dunes were reconstructed using Digital Terrain Models (DTM) derived from stereo observations made by Unmanned Aerial Vehicles (UAV). Based on this, the volumetric change of sand dunes was directly estimated through co-registered DTMs. We furthermore derived and investigated topographic parameters, such as the aerodynamic roughness length, the protrusion coefficient, the Normalized Difference Angular Index, and the phase coherence derived from spaceborne optical/synthetic aperture radar (SAR) remote sensing assets with the calibration index from UAV observation. Throughout such a multi-data approach, temporal changes of a target's environmental parameters can be traced, analyzed and correlated with weather conditions. An improved understanding of aeolian processes in sand deserts will be a valuable contribution for desertification combat activities and early warning systems for dust storm generation. Future research needs to be conducted over more extensive spatial and temporal domains, also by combining investigations on the

  16. Reference intervals and physiologic alterations in hematologic and biochemical values of free-ranging desert tortoises in the Mojave Desert

    Science.gov (United States)

    Christopher, Mary M.; Berry, Kristin H.; Wallis, I.R.; Nagy, K.A.; Henen, B.T.; Peterson, C.C.

    1999-01-01

    Desert tortoise (Gopherus agassizii) populations have experienced precipitous declines resulting from the cumulative impact of habitat loss, and human and disease-related mortality. Evaluation of hematologic and biochemical responses of desert tortoises to physiologic and environmental factors can facilitate the assessment of stress and disease in tortoises and contribute to management decisions and population recovery. The goal of this study was to obtain and analyze clinical laboratory data from free-ranging desert tortoises at three sites in the Mojave Desert (California, USA) between October 1990 and October 1995, to establish reference intervals, and to develop guidelines for the interpretation of laboratory data under a variety of environmental and physiologic conditions. Body weight, carapace length, and venous blood samples for a complete blood count and clinical chemistry profile were obtained from 98 clinically healthy adult desert tortoises of both sexes at the Desert Tortoise Research Natural area (western Mojave), Goffs (eastern Mojave) and Ivanpah Valley (northeastern Mojave). Samples were obtained four times per year, in winter (February/March), spring (May/June), summer (July/August), and fall (October). Years of near-, above- and below-average rainfall were represented in the 5 yr period. Minimum, maximum and median values, and central 95 percentiles were used as reference intervals and measures of central tendency for tortoises at each site and/or season. Data were analyzed using repeated measures analysis of variance for significant (P < 0.01) variation on the basis of sex, site, season, and interactions between these variables. Significant sex differences were observed for packed cell volume, hemoglobin concentration, aspartate transaminase activity, and cholesterol, triglyceride, calcium, and phosphorus concentrations. Marked seasonal variation was observed in most parameters in conjunction with reproductive cycle, hibernation, or seasonal

  17. Effects of altered temperature and precipitation on desert protozoa associated with biological soil crusts.

    Science.gov (United States)

    Darby, Brian J; Housman, David C; Zaki, Amr M; Shamout, Yassein; Adl, Sina M; Belnap, Jayne; Neher, Deborah A

    2006-01-01

    Biological soil crusts are diverse assemblages of bacteria, cyanobacteria, algae, fungi, lichens, and mosses that cover much of arid land soils. The objective of this study was to quantify protozoa associated with biological soil crusts and test the response of protozoa to increased temperature and precipitation as is predicted by some global climate models. Protozoa were more abundant when associated with cyanobacteria/lichen crusts than with cyanobacteria crusts alone. Amoebae, flagellates, and ciliates originating from the Colorado Plateau desert (cool desert, primarily winter precipitation) declined 50-, 10-, and 100-fold, respectively, when moved in field mesocosms to the Chihuahuan Desert (hot desert, primarily summer rain). However, this was not observed in protozoa collected from the Chihuahuan Desert and moved to the Sonoran desert (hot desert, also summer rain, but warmer than Chihuahuan Desert). Protozoa in culture began to encyst at 37 degrees C. Cysts survived the upper end of daily temperatures (37-55 degrees C), and could be stimulated to excyst if temperatures were reduced to 15 degrees C or lower. Results from this study suggest that cool desert protozoa are influenced negatively by increased summer precipitation during excessive summer temperatures, and that desert protozoa may be adapted to a specific desert's temperature and precipitation regime.

  18. Water use sources of desert riparian Populus euphratica forests.

    Science.gov (United States)

    Si, Jianhua; Feng, Qi; Cao, Shengkui; Yu, Tengfei; Zhao, Chunyan

    2014-09-01

    Desert riparian forests are the main body of natural oases in the lower reaches of inland rivers; its growth and distribution are closely related to water use sources. However, how does the desert riparian forest obtains a stable water source and which water sources it uses to effectively avoid or overcome water stress to survive? This paper describes an analysis of the water sources, using the stable oxygen isotope technique and the linear mixed model of the isotopic values and of desert riparian Populus euphratica forests growing at sites with different groundwater depths and conditions. The results showed that the main water source of Populus euphratica changes from water in a single soil layer or groundwater to deep subsoil water and groundwater as the depth of groundwater increases. This appears to be an adaptive selection to arid and water-deficient conditions and is a primary reason for the long-term survival of P. euphratica in the desert riparian forest of an extremely arid region. Water contributions from the various soil layers and from groundwater differed and the desert riparian P. euphratica forests in different habitats had dissimilar water use strategies.

  19. Pop / Mart Juur

    Index Scriptorium Estoniae

    Juur, Mart, 1964-

    2002-01-01

    Heliplaatidest: Robbie Williams "Escapalogy", Suicide "American Supreme", Audioslave "Audioslave", Sigur Ros "()", Natacha Atlas & Mark Eagleton Project "Foretold in the Language of Dreams", Iron Maiden "Edward the Great", Gregorian "Masters Of Chant Chapter III", Everything But The Girl "Like Desert Miss The Rain"

  20. Remote Sensing of Sonoran Desert Vegetation Structure and Phenology with Ground-Based LiDAR

    Directory of Open Access Journals (Sweden)

    Joel B. Sankey

    2014-12-01

    Full Text Available Long-term vegetation monitoring efforts have become increasingly important for understanding ecosystem response to global change. Many traditional methods for monitoring can be infrequent and limited in scope. Ground-based LiDAR is one remote sensing method that offers a clear advancement to monitor vegetation dynamics at high spatial and temporal resolution. We determined the effectiveness of LiDAR to detect intra-annual variability in vegetation structure at a long-term Sonoran Desert monitoring plot dominated by cacti, deciduous and evergreen shrubs. Monthly repeat LiDAR scans of perennial plant canopies over the course of one year had high precision. LiDAR measurements of canopy height and area were accurate with respect to total station survey measurements of individual plants. We found an increase in the number of LiDAR vegetation returns following the wet North American Monsoon season. This intra-annual variability in vegetation structure detected by LiDAR was attributable to a drought deciduous shrub Ambrosia deltoidea, whereas the evergreen shrub Larrea tridentata and cactus Opuntia engelmannii had low variability. Benefits of using LiDAR over traditional methods to census desert plants are more rapid, consistent, and cost-effective data acquisition in a high-resolution, 3-dimensional context. We conclude that repeat LiDAR measurements can be an effective method for documenting ecosystem response to desert climatology and drought over short time intervals and at detailed-local spatial scale.

  1. Stable Isotopic Analysis on Water Utilization of Two Xerophytic Shrubs in a Revegetated Desert Area: Tengger Desert, China

    OpenAIRE

    Lei Huang; Zhishan Zhang

    2015-01-01

    Stable isotope studies on stable isotope ratios of hydrogen and oxygen in water within plants provide new information on water sources and water use patterns under natural conditions. In this study, the sources of water uptake for two typical xerophytic shrubs, Caragana korshinskii and Artemisia ordosica, were determined at four different-aged revegetated sites (1956, 1964, 1981, and 1987) in the Tengger Desert, a revegetated desert area in China. Samples from precipitation, soil water at dif...

  2. Geology and geochemistry of the Atacama Desert.

    Science.gov (United States)

    Tapia, J; González, R; Townley, B; Oliveros, V; Álvarez, F; Aguilar, G; Menzies, A; Calderón, M

    2018-02-14

    The Atacama Desert, the driest of its kind on Earth, hosts a number of unique geological and geochemical features that make it unlike any other environment on the planet. Considering its location on the western border of South America, between 17 and 28 °S, its climate has been characterized as arid to hyperarid for at least the past 10 million years. Notably dry climatic conditions of the Atacama Desert have been related to uplift of the Andes and are believed to have played an important role in the development of the most distinctive features of this desert, including: (i) nitrates and iodine deposits in the Central Depression, (ii) secondary enrichment in porphyry copper deposits in the Precordillera, (iii) Li enrichment in salt flats of the Altiplano, and (iv) life in extreme habitats. The geology and physiography of the Atacama Desert have been largely shaped by the convergent margin present since the Mesozoic era. The geochemistry of surface materials is related to rock geochemistry (Co, Cr, Fe, Mn, V, and Zn), salt flats, and evaporite compositions in endorheic basins (As, B, and Li), in addition to anthropogenic activities (Cu, Mo, and Pb). The composition of surface water is highly variable, nonetheless in general it presents a circumneutral pH with higher conductivity and total dissolved solids in brines. Major water constituents, with the exception of HCO 3 - , are generally related to the increase of salinity, and despite the fact that trace elements are not well-documented, surface waters of the Atacama Desert are enriched in As, B, and Li when compared to the average respective concentrations in rivers worldwide.

  3. Liquid Water Restricts Habitability in Extreme Deserts.

    Science.gov (United States)

    Cockell, Charles S; Brown, Sarah; Landenmark, Hanna; Samuels, Toby; Siddall, Rebecca; Wadsworth, Jennifer

    2017-04-01

    Liquid water is a requirement for biochemistry, yet under some circumstances it is deleterious to life. Here, we show that liquid water reduces the upper temperature survival limit for two extremophilic photosynthetic microorganisms (Gloeocapsa and Chroococcidiopsis spp.) by greater than 40°C under hydrated conditions compared to desiccated conditions. Under hydrated conditions, thermal stress causes protein inactivation as shown by the fluorescein diacetate assay. The presence of water was also found to enhance the deleterious effects of freeze-thaw in Chroococcidiopsis sp. In the presence of water, short-wavelength UV radiation more effectively kills Gloeocapsa sp. colonies, which we hypothesize is caused by factors including the greater penetration of UV radiation into hydrated colonies compared to desiccated colonies. The data predict that deserts where maximum thermal stress or irradiation occurs in conjunction with the presence of liquid water may be less habitable to some organisms than more extreme arid deserts where organisms can dehydrate prior to being exposed to these extremes, thus minimizing thermal and radiation damage. Life in extreme deserts is poised between the deleterious effects of the presence and the lack of liquid water. Key Words: Deserts-Extremophiles-Stress-High temperatures-UV radiation-Desiccation. Astrobiology 17, 309-318.

  4. Water/Pasture Assessment of Registan Desert (Kandahar and Helmand Provinces)

    OpenAIRE

    Toderich, Kristina; Tsukatani, Tsuneo

    2005-01-01

    The desolate desert in Afghanistan's Kandahar and Helmand Provinces was previously populated by thousands of pastoralists until a devastating drought decimated animal herds and forced them to live as IDPs (Internally Displaced Persons) on land bordering the desert. Through funding from UNAMA (United Nations Assistance Mission in Afghanistan), this report assesses conditions in the Registan Desert and border regions to devise solutions to the problems facing Registan Kuchi nomads. A work plan ...

  5. Strategy for the development and management of deserts

    Energy Technology Data Exchange (ETDEWEB)

    1978-02-01

    Recommendations from the June 1977 Conference on Alternative Strategies for Desert Development and Management apply primarily to arid lands, although some can be applied to true desert with no vegetation as well. The causes of desertification are reviewed and corrective measures suggested for both developed and developing countries. A range of strategies is proposed, but all are based on the efficient use of water and most are concerned with water used for agricultural purposes. The conference papers also addressed water management, agricultural development, field crops versus animal husbandry, grazing, land use and allocation, wild life resources, industry coastal resources, tourism, energy and minerals, and establishing the infrastructure needed to improve and retain desert health.

  6. A Proteome Translocation Response to Complex Desert Stress Environments in Perennial Phragmites Sympatric Ecotypes with Contrasting Water Availability.

    Science.gov (United States)

    Li, Li; Chen, Xiaodan; Shi, Lu; Wang, Chuanjing; Fu, Bing; Qiu, Tianhang; Cui, Suxia

    2017-01-01

    After a long-term adaptation to desert environment, the perennial aquatic plant Phragmites communis has evolved a desert-dune ecotype. The desert-dune ecotype (DR) of Phragmites communis showed significant differences in water activity and protein distribution compared to its sympatric swamp ecotype (SR). Many proteins that were located in the soluble fraction of SR translocated to the insoluble fraction of DR, suggesting that membrane-associated proteins were greatly reinforced in DR. The unknown phenomenon in plant stress physiology was defined as a proteome translocation response. Quantitative 2D-DIGE technology highlighted these 'bound' proteins in DR. Fifty-eight kinds of proteins were identified as candidates of the translocated proteome in Phragmites . The majority were chloroplast proteins. Unexpectedly, Rubisco was the most abundant protein sequestered by DR. Rubisco activase, various chaperons and 2-cysteine peroxiredoxin were major components in the translocation response. Conformational change was assumed to be the main reason for the Rubisco translocation due to no primary sequence difference between DR and SR. The addition of reductant in extraction process partially reversed the translocation response, implying that intracellular redox status plays a role in the translocation response of the proteome. The finding emphasizes the realistic significance of the membrane-association of biomolecule for plant long-term adaptation to complex stress conditions.

  7. The provenance of Taklamakan desert sand

    Science.gov (United States)

    Rittner, Martin; Vermeesch, Pieter; Carter, Andrew; Bird, Anna; Stevens, Thomas; Garzanti, Eduardo; Andò, Sergio; Vezzoli, Giovanni; Dutt, Ripul; Xu, Zhiwei; Lu, Huayu

    2016-03-01

    Sand migration in the vast Taklamakan desert within the Tarim Basin (Xinjiang Uyghur Autonomous region, PR China) is governed by two competing transport agents: wind and water, which work in diametrically opposed directions. Net aeolian transport is from northeast to south, while fluvial transport occurs from the south to the north and then west to east at the northern rim, due to a gradual northward slope of the underlying topography. We here present the first comprehensive provenance study of Taklamakan desert sand with the aim to characterise the interplay of these two transport mechanisms and their roles in the formation of the sand sea, and to consider the potential of the Tarim Basin as a contributing source to the Chinese Loess Plateau (CLP). Our dataset comprises 39 aeolian and fluvial samples, which were characterised by detrital-zircon U-Pb geochronology, heavy-mineral, and bulk-petrography analyses. Although the inter-sample differences of all three datasets are subtle, a multivariate statistical analysis using multidimensional scaling (MDS) clearly shows that Tarim desert sand is most similar in composition to rivers draining the Kunlun Shan (south) and the Pamirs (west), and is distinctly different from sediment sources in the Tian Shan (north). A small set of samples from the Junggar Basin (north of the Tian Shan) yields different detrital compositions and age spectra than anywhere in the Tarim Basin, indicating that aeolian sediment exchange between the two basins is minimal. Although river transport dominates delivery of sand into the Tarim Basin, wind remobilises and reworks the sediment in the central sand sea. Characteristic signatures of main rivers can be traced from entrance into the basin to the terminus of the Tarim River, and those crossing the desert from the south to north can seasonally bypass sediment through the sand sea. Smaller ephemeral rivers from the Kunlun Shan end in the desert and discharge their sediment there. Both river run

  8. From Fireproof Desert to Flammable Grassland: Buffelgrass Invasion in the Sonoran Desert

    Science.gov (United States)

    Betancourt, J. L.

    2007-12-01

    Only a few decades ago, the Sonoran Desert of northwestern Mexico and southern Arizona was considered mostly fireproof, a case of not enough fine fuel to connect the dominant shrubs and cacti. This has changed with invasions by non-native, winter annual and summer-flower perennial grasses that are rapidly transforming fireproof desert into flammable grassland. Of particular concern is buffelgrass, Pennisetum ciliare, a fire-prone and invasive African perennial grass that has already converted millions of hectares across Sonora since the mid-1960s and has made quick headway in southern and central Arizona beginning in the 1980s. Near Tucson and Phoenix, AZ, buffelgrass invasion is proceeding exponentially, with population expansion (and the costs of mitigation) more than doubling every year. As this conversion progresses, there will be increased fire risks, lost tourist revenue, diminished property values, insurmountable setbacks to conservation efforts, and the threat of large ignition fronts in desert valleys routinely spreading into the mountains. Although somewhat belated, an integrated, multi-jurisdictional effort is being organized to reduce ecological and economic impacts. My presentation will summarize the history and context of buffelgrass introduction and invasion, the disconnect in attitudes and policies across state and international boundaries, ongoing management efforts, the role of science and responsibilities of scientists, accelerated spread with changing climate, and impacts to regional ecosystems and economies. This narrative may serve as a template for other semi-arid lands where buffelgrass and similar grasses have become invasive, including Australia, South America, and many islands in the Pacific Ocean (including Hawaii), Indian Ocean, and Caribbean Sea.

  9. Using the Web To Explore the Great Depression.

    Science.gov (United States)

    Chamberlin, Paul

    2001-01-01

    Presents an annotated list of Web sites that focus on the Great Depression. Includes the American Experience, American Memory, the National Archives and Records Administration, and the New Deal Network Web sites. Offers additional sites covering topics such as the Jersey homesteads and labor history. (CMK)

  10. Global Warming: The Instability of Desert Climate is Enhancing in the Northwest Area in China: A Case Study in the Desert Area in Northwestern China

    OpenAIRE

    Zhao-Feng Chang; Shu-Juan Zhu; Fu-Gui Han; Sheng-Nnian Zhong; Qiang-Qiang Wang; Jian-Hui Zhang

    2013-01-01

    To disclose the relation between the sandstorms change and the temperature changes, a case study in the desert area in northwestern china is investigated. The results showed that: the instability of climate in Minqin desert area is enhancing in the arid desert region in northwest China. Mainly as follows: Variation the annual extreme maximum temperature increasing. Variation of extreme minimum temperature also an increasing trend. Average visibility of sandstorms significantly reduced and the...

  11. Health effects of particulate air pollution and airborne desert dust

    Science.gov (United States)

    Lelieveld, J.; Pozzer, A.; Giannadaki, D.; Fnais, M.

    2013-12-01

    Air pollution by fine particulate matter (PM2.5) has increased strongly with industrialization and urbanization. In the past decades this increase has taken place at a particularly high pace in South and East Asia. We estimate the premature mortality and the years of human life lost (YLL) caused by anthropogenic PM2.5 and airborne desert dust (DU2.5) on regional and national scales (Giannadaki et al., 2013; Lelieveld et al., 2013). This is based on high-resolution global model calculations that resolve urban and industrial regions in relatively great detail. We apply an epidemiological health impact function and find that especially in large countries with extensive suburban and rural populations, air pollution-induced mortality rates have been underestimated given that previous studies largely focused on the urban environment. We calculate a global premature mortality by anthropogenic aerosols of 2.2 million/year (YLL ≈ 16 million/year) due to lung cancer and cardiopulmonary disease. High mortality rates by PM2.5 are found in China, India, Bangladesh, Pakistan and Indonesia. Desert dust DU2.5 aerosols add about 0.4 million/year (YLL ≈ 3.6 million/year). Particularly significant mortality rates by DU2.5 occur in Pakistan, China and India. The estimated global mean per capita mortality caused by airborne particulates is about 0.1%/year (about two thirds of that caused by tobacco smoking). We show that the highest premature mortality rates are found in the Southeast Asia and Western Pacific regions (about 25% and 46% of the global rate, respectively) where more than a dozen of the most highly polluted megacities are located. References: Giannadaki, D., A. Pozzer, and J. Lelieveld, Modeled global effects of airborne desert dust on air quality and premature mortality, Atmos. Chem. Phys. Discuss. (submitted), 2013. Lelieveld, J., C. Barlas, D. Giannadaki, and A. Pozzer, Model calculated global, regional and megacity premature mortality due to air pollution by ozone

  12. Birds and conservation significance of the Namib Desert's least ...

    African Journals Online (AJOL)

    -long Namib Desert and it remains the least known coastal wetland on a desert coast rich in shorebirds. Two surveys of the Baia dos Tigres region in 1999 and 2001 indicated a rich wetland bird diversity consisting of 25 species, with a total of ...

  13. Tree planting in deserts and utilization of atomic energy

    International Nuclear Information System (INIS)

    Hattori, Sadao; Minato, Akio; Hashizume, Kenichi; Handa, Norihiko.

    1991-01-01

    Global environment problems are discussed actively, concretely, those are the warming of the earth, the advance of desertification, the damage due to acid rain, the decrease of tropical forests, the pollution of sea, the depletion of ozone layer and so on. Most of these phenomena advance gradually. However, the advance of desertification is different from other phenomena in that the people in the areas concerned are deprived of their living space and even their lives are threatened at this moment. Desertification is advancing on global scale, and its rate is estimated to be 60,000 km 2 yearly. Especially the area where the advance is remarkable is the southern edge of Sahara Desert, which advances southward at 10-30 km in one year. Recently also in Japan, the interest in the prevention of desertification has become high, and the experiment on tree planting in a desert using a huge desert dome of the Institute of Physical and Chemical Research, 'Desert Aquanet concept' of Shimizu Construction Co., Ltd., 'Sahara green belt project' of the Ministry of International Trade and Industry and so on were published. Water and energy for tree planting in deserts, utilization of atomic energy for seawater desalination and the technical fields to which Japan can contribute are reported. (K.I.)

  14. Tree planting in deserts and utilization of atomic energy

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, Sadao; Minato, Akio [Central Research Inst. of Electric Power Industry, Tokyo (Japan); Hashizume, Kenichi; Handa, Norihiko

    1991-06-01

    Global environment problems are discussed actively, concretely, those are the warming of the earth, the advance of desertification, the damage due to acid rain, the decrease of tropical forests, the pollution of sea, the depletion of ozone layer and so on. Most of these phenomena advance gradually. However, the advance of desertification is different from other phenomena in that the people in the areas concerned are deprived of their living space and even their lives are threatened at this moment. Desertification is advancing on global scale, and its rate is estimated to be 60,000 km{sup 2} yearly. Especially the area where the advance is remarkable is the southern edge of Sahara Desert, which advances southward at 10-30 km in one year. Recently also in Japan, the interest in the prevention of desertification has become high, and the experiment on tree planting in a desert using a huge desert dome of the Institute of Physical and Chemical Research, 'Desert Aquanet concept' of Shimizu Construction Co., Ltd., 'Sahara green belt project' of the Ministry of International Trade and Industry and so on were published. Water and energy for tree planting in deserts, utilization of atomic energy for seawater desalination and the technical fields to which Japan can contribute are reported. (K.I.).

  15. Screening the Egyptian desert actinomycetes as candidates for new ...

    African Journals Online (AJOL)

    In a screening program to study the antimicrobial activities of desert actinomycetes as potential producers of active metabolites, 75 actinomycete strains were isolated from the Egyptian desert habitats and tested. Out of the isolated 75 organisms, 32 (42.67%) showed activity against the used test organisms.

  16. Camelid genomes reveal evolution and adaptation to desert environments.

    Science.gov (United States)

    Wu, Huiguang; Guang, Xuanmin; Al-Fageeh, Mohamed B; Cao, Junwei; Pan, Shengkai; Zhou, Huanmin; Zhang, Li; Abutarboush, Mohammed H; Xing, Yanping; Xie, Zhiyuan; Alshanqeeti, Ali S; Zhang, Yanru; Yao, Qiulin; Al-Shomrani, Badr M; Zhang, Dong; Li, Jiang; Manee, Manee M; Yang, Zili; Yang, Linfeng; Liu, Yiyi; Zhang, Jilin; Altammami, Musaad A; Wang, Shenyuan; Yu, Lili; Zhang, Wenbin; Liu, Sanyang; Ba, La; Liu, Chunxia; Yang, Xukui; Meng, Fanhua; Wang, Shaowei; Li, Lu; Li, Erli; Li, Xueqiong; Wu, Kaifeng; Zhang, Shu; Wang, Junyi; Yin, Ye; Yang, Huanming; Al-Swailem, Abdulaziz M; Wang, Jun

    2014-10-21

    Bactrian camel (Camelus bactrianus), dromedary (Camelus dromedarius) and alpaca (Vicugna pacos) are economically important livestock. Although the Bactrian camel and dromedary are large, typically arid-desert-adapted mammals, alpacas are adapted to plateaus. Here we present high-quality genome sequences of these three species. Our analysis reveals the demographic history of these species since the Tortonian Stage of the Miocene and uncovers a striking correlation between large fluctuations in population size and geological time boundaries. Comparative genomic analysis reveals complex features related to desert adaptations, including fat and water metabolism, stress responses to heat, aridity, intense ultraviolet radiation and choking dust. Transcriptomic analysis of Bactrian camels further reveals unique osmoregulation, osmoprotection and compensatory mechanisms for water reservation underpinned by high blood glucose levels. We hypothesize that these physiological mechanisms represent kidney evolutionary adaptations to the desert environment. This study advances our understanding of camelid evolution and the adaptation of camels to arid-desert environments.

  17. Jojoba could stop the desert creep

    Energy Technology Data Exchange (ETDEWEB)

    1982-03-25

    The Sahara desert is estimated to be expanding at a rate of 5km a year. The Sudanese government is experimenting with jojoba in six different regions as the bush has the potential to stop this ''desert creep''. The plant, a native to Mexico, is long known for its resistance to drought and for the versatile liquid wax that can be extracted from its seeds. It is estimated that one hectare of mature plants could produce 3000 kg of oil, currently selling at $50 per litre, and so earn valuable foreign currency.

  18. Closed bioregenerative life support systems: Applicability to hot deserts

    Science.gov (United States)

    Polyakov, Yuriy S.; Musaev, Ibrahim; Polyakov, Sergey V.

    2010-09-01

    Water scarcity in hot deserts, which cover about one-fifth of the Earth's land area, along with rapid expansion of hot deserts into arable lands is one of the key global environmental problems. As hot deserts are extreme habitats characterized by the availability of solar energy with a nearly complete absence of organic life and water, space technology achievements in designing closed ecological systems may be applicable to the design of sustainable settlements in the deserts. This review discusses the key space technology findings for closed biogenerative life support systems (CBLSS), which can simultaneously produce food, water, nutrients, fertilizers, process wastes, and revitalize air, that can be applied to hot deserts. Among them are the closed cycle of water and the acceleration of the cycling times of carbon, biogenic compounds, and nutrients by adjusting the levels of light intensity, temperature, carbon dioxide, and air velocity over plant canopies. Enhanced growth of algae and duckweed at higher levels of carbon dioxide and light intensity can be important to provide complete water recycling and augment biomass production. The production of fertilizers and nutrients can be enhanced by applying the subsurface flow wetland technology and hyper-thermophilic aerobic bacteria for treating liquid and solid wastes. The mathematical models, optimization techniques, and non-invasive measuring techniques developed for CBLSS make it possible to monitor and optimize the performance of such closed ecological systems. The results of long-duration experiments performed in BIOS-3, Biosphere 2, Laboratory Biosphere, and other ground-based closed test facilities suggest that closed water cycle can be achieved in hot-desert bioregenerative systems using the pathways of evapotranspiration, condensation, and biological wastewater treatment technologies. We suggest that the state of the art in the CBLSS design along with the possibility of using direct sunlight for

  19. Disturbance and Plant Succession in the Mojave and Sonoran Deserts of the American Southwest

    Directory of Open Access Journals (Sweden)

    Scott R. Abella

    2010-03-01

    Full Text Available Disturbances such as fire, land clearing, and road building remove vegetation and can have major influences on public health through effects on air quality, aesthetics, recreational opportunities, natural resource availability, and economics. Plant recovery and succession following disturbance are poorly understood in arid lands relative to more temperate regions. This study quantitatively reviewed vegetation reestablishment following a variety of disturbances in the Mojave and Sonoran Deserts of southwestern North America. A total of 47 studies met inclusion criteria for the review. The time estimated by 29 individual studies for full reestablishment of total perennial plant cover was 76 years. Although long, this time was shorter than an estimated 215 years (among 31 individual studies required for the recovery of species composition typical of undisturbed areas, assuming that recovery remains linear following the longest time since disturbance measurement made by the studies.

  20. Investigating water resources of the desert: How isotopes can help

    International Nuclear Information System (INIS)

    Gonfiantini, R.

    1992-01-01

    Newspapers and magazines from time to time write about the enormous reserves of water stored underground in the Sahara, whose rational exploitation would allow the agricultural development of the desert. Although the practical implementation of such projects is rather problematic, it is true that groundwater is relatively abundant under most of the Sahara (as well as in other deserts in the world), but it is seldom easily accessible. What do we really know about these resources of groundwater and how they have accumulated in areas where rainfall is so scarce. What do we know of the hydrological history of the desert. These problems are important for the correct evaluation and use of the groundwater in the desert. Isotope techniques help in their solution, and are described in this document. 6 figs

  1. Investigating water resources of the desert: how isotopes can help

    International Nuclear Information System (INIS)

    Gonfiantini, R.

    1981-01-01

    Newspapers and magazines from time to time write about the enormous reserves of water stored underground in the Sahara, whose rational exploitation would allow the agricultural development of the desert. Although the practical implementation of such projects is rather problematic, it is true that groundwater is relatively abundant under most of the Sahara (as well as in other deserts in the world), but it is seldom easily accessible. What do we really know about these resources of groundwater and how they have accumulated in areas where rainfall is so scarce. What do we know of the hydrological history of the desert. These problems are important for the correct evaluation and use of the groundwater in the desert. Isotope techniques help in their solution, and are described in this document

  2. The Desert and the Sown Project in Northern Jordan

    DEFF Research Database (Denmark)

    Kerner, Susanne

    2014-01-01

    The desert and sown project, which started in 1999 and continued in 2008-2009, studied the region between the settled areas east of Irbid and Ramtha and the surrounding desert at Mafraq (northern Jordan). Large parts of the material comes from the Palaeolithic period, while some smaller tells date...

  3. Making Research Delicious: An Evaluation of Nurses' Knowledge, Attitudes, and Practice Using the Great American Cookie Experiment With Mobile Device Gaming.

    Science.gov (United States)

    Hayes Lane, Susan; Serafica, Reimund; Huffman, Carolyn; Cuddy, Alyssa

    2016-01-01

    In the current healthcare environment, nurses must have a basic understanding of research to lead change and implement evidence-based practice. The purpose of this study was to evaluate the effectiveness of an educational intervention formulated on the framework of the Great American Cookie Experiment measuring nurses' research knowledge, attitudes, and practice using mobile device gaming. This multisite quantitative study provides insight into promotion of research and information about best practices on innovative teaching strategies for nurses.

  4. Pleistocene climate change and the origin of two desert plant species, Pugionium cornutum and Pugionium dolabratum (Brassicaceae), in northwest China.

    Science.gov (United States)

    Wang, Qian; Abbott, Richard J; Yu, Qiu-Shi; Lin, Kao; Liu, Jian-Quan

    2013-07-01

    Pleistocene climate change has had an important effect in shaping intraspecific genetic variation in many species; however, its role in driving speciation is less clear. We examined the possibility of a Pleistocene origin of the only two representatives of the genus Pugionium (Brassicaceae), Pugionium cornutum and Pugionium dolabratum, which occupy different desert habitats in northwest China. We surveyed sequence variation for internal transcribed spacer (ITS), three chloroplast (cp) DNA fragments, and eight low-copy nuclear genes among individuals sampled from 11 populations of each species across their geographic ranges. One ITS mutation distinguished the two species, whereas mutations in cpDNA and the eight low-copy nuclear gene sequences were not species-specific. Although interspecific divergence varied greatly among nuclear gene sequences, in each case divergence was estimated to have occurred within the Pleistocene when deserts expanded in northwest China. Our findings point to the importance of Pleistocene climate change, in this case an increase in aridity, as a cause of speciation in Pugionium as a result of divergence in different habitats that formed in association with the expansion of deserts in China. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  5. Observed 20th Century Desert Dust Variability: Impact on Climate and Biogeochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Mahowald, Natalie [Cornell University; Kloster, Silvia [Cornell University; Engelstaedter, S. [Cornell University; Moore, Jefferson Keith [University of California, Irvine; Mukhopadhyay, S. [Harvard University; McConnell, J. R. [Desert Research Institute, Reno, NV; Albani, S. [Cornell University; Doney, Scott C. [Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA; Bhattacharya, A. [Harvard University; Curran, M. A. J. [Antarctic Climate and Ecosystems Cooperative Research Centre; Flanner, Mark G. [University of Michigan; Hoffman, Forrest M [ORNL; Lawrence, David M. [National Center for Atmospheric Research (NCAR); Lindsay, Keith [National Center for Atmospheric Research (NCAR); Mayewski, P. A. [University of Maine; Neff, Jason [University of Colorado, Boulder; Rothenberg, D. [Cornell University; Thomas, E. [British Antarctic Survey, Cambridge, UK; Thornton, Peter E [ORNL; Zender, Charlie S. [University of California, Irvine

    2010-01-01

    Desert dust perturbs climate by directly and indirectly interacting with incoming solar and outgoing long wave radiation, thereby changing precipitation and temperature, in addition to modifying ocean and land biogeochemistry. While we know that desert dust is sensitive to perturbations in climate and human land use, previous studies have been unable to determine whether humans were increasing or decreasing desert dust in the global average. Here we present observational estimates of desert dust based on paleodata proxies showing a doubling of desert dust during the 20th century over much, but not all the globe. Large uncertainties remain in estimates of desert dust variability over 20th century due to limited data. Using these observational estimates of desert dust change in combination with ocean, atmosphere and land models, we calculate the net radiative effect of these observed changes (top of atmosphere) over the 20th century to be -0.14 {+-} 0.11 W/m{sup 2} (1990-1999 vs. 1905-1914). The estimated radiative change due to dust is especially strong between the heavily loaded 1980-1989 and the less heavily loaded 1955-1964 time periods (-0.57 {+-} 0.46 W/m{sup 2}), which model simulations suggest may have reduced the rate of temperature increase between these time periods by 0.11 C. Model simulations also indicate strong regional shifts in precipitation and temperature from desert dust changes, causing 6 ppm (12 PgC) reduction in model carbon uptake by the terrestrial biosphere over the 20th century. Desert dust carries iron, an important micronutrient for ocean biogeochemistry that can modulate ocean carbon storage; here we show that dust deposition trends increase ocean productivity by an estimated 6% over the 20th century, drawing down an additional 4 ppm (8 PgC) of carbon dioxide into the oceans. Thus, perturbations to desert dust over the 20th century inferred from observations are potentially important for climate and biogeochemistry, and our understanding

  6. Pastoralist rock art in the Black Desert of Jordan

    NARCIS (Netherlands)

    Brusgaard, N.O.

    2015-01-01

    This paper discusses the current problems that exist with the rock art research of the Black Desert in Jordan and presents some preliminary field results of the author’s research on the petroglyphs. It also explore the possibilities that the rock art affords to learn more about the elusive desert

  7. 76 FR 8730 - Desert Southwest Customer Service Region-Rate Order No. WAPA-151

    Science.gov (United States)

    2011-02-15

    ... DEPARTMENT OF ENERGY Western Area Power Administration Desert Southwest Customer Service Region.... Jack Murray, Rates Manager, Desert Southwest Customer Service Region, Western Area Power Administration... ancillary service rates for the Desert Southwest Customer Service Region in accordance with section 302 of...

  8. Production of desert rose seedlings in different potting media

    Directory of Open Access Journals (Sweden)

    Ronan Carlos Colombo

    2017-09-01

    Full Text Available Over the past decade the desert rose received fame in the flower market due to its striking and sculptural forms; however, the commercial production of these species is quite recent and little is known about its crop management, including substrates recommendation. The objectives of this study were to investigate the effect of different substrates on desert rose seed germination and production of its seedlings. Experiment I: freshly harvested seeds of desert rose were sown in different substrates e.g. sand, coconut fiber, semi-composted pine bark, sand + coconut fiber, semi-composted pine bark + sand and coconut fiber + semicomposted pine bark. These substrates were evaluated to study the emergence percentage of seeds, initial growth of seedlings and seedling emergence speed index (ESI. Experiment II: desert rose from the experiment I were transferred to plastic pots filled with the same substrates as in experiment I. The pH and electrical conductivity (EC of the substrates were noted every 30 days while the growth parameters of seedlings were recorded after 240 days. Results from experiment I showed higher germination rate and seedling growth in substrates containing semi-composted pine bark. Similarly, in experiment II, better quality seedlings were observed in substrates containing semi-composted pine bark. Thus, for desert rose seed germination and seedling growth, it is recommended to use substrates containing semi-composted pine bark.

  9. Pollen spectrum, a cornerstone for tracing the evolution of the eastern Central Asian desert

    Science.gov (United States)

    Lu, Kai-Qing; Xie, Gan; Li, Min; Li, Jin-Feng; Trivedi, Anjali; Ferguson, David K.; Yao, Yi-Feng; Wang, Yu-Fei

    2018-04-01

    The temperate desert in arid Central Asia (ACA) has acted as a thoroughfare for the ancient Silk Road and today's Belt and Road, linking economic and cultural exchanges between East and West. The interaction between human sustainable development and the dynamic change in the desert ecosystem in this region is an area of concern for governments and scientific communities. Nevertheless, the lack of a pollen spectrum of the dominant taxa within the temperate desert vegetation and a corresponding relation between pollen assemblages and specific desert vegetation types is an obstacle to further understanding the formation and maintenance of this desert ecosystem. In this work, we link pollen assemblages to specific desert vegetation types with a new pollen spectrum with specific pollen grains, specific plant taxa and related habitats, providing a solid foundation for further tracing the evolution of the desert ecosystem in eastern arid Central Asia.

  10. Ecosystem responses to warming and watering in typical and desert steppes

    Science.gov (United States)

    Xu, Zhenzhu; Hou, Yanhui; Zhang, Lihua; Liu, Tao; Zhou, Guangsheng

    2016-10-01

    Global warming is projected to continue, leading to intense fluctuations in precipitation and heat waves and thereby affecting the productivity and the relevant biological processes of grassland ecosystems. Here, we determined the functional responses to warming and altered precipitation in both typical and desert steppes. The results showed that watering markedly increased the aboveground net primary productivity (ANPP) in a typical steppe during a drier year and in a desert steppe over two years, whereas warming manipulation had no significant effect. The soil microbial biomass carbon (MBC) and the soil respiration (SR) were increased by watering in both steppes, but the SR was significantly decreased by warming in the desert steppe only. The inorganic nitrogen components varied irregularly, with generally lower levels in the desert steppe. The belowground traits of soil total organic carbon (TOC) and the MBC were more closely associated with the ANPP in the desert than in the typical steppes. The results showed that the desert steppe with lower productivity may respond strongly to precipitation changes, particularly with warming, highlighting the positive effect of adding water with warming. Our study implies that the habitat- and year-specific responses to warming and watering should be considered when predicting an ecosystem’s functional responses under climate change scenarios.

  11. Monitoring of desert dune topography by multi angle sensors

    Science.gov (United States)

    Yun, J.; Kim, J.; Choi, Y.; Yun, H.

    2011-12-01

    Nowadays, the sandy desert is rapidly expanding world widely and results in a lot of risks in the socio-econimical aspects as well as the anthropogenic activities. For example, the increasing occurrences of mineral dust storm which presumably originated from the sandy deserts in northwest China become a serious threat in human activities as well as public health over Far East Asian area as the interpretation by the MODIS analysis (Zhang et al., 2007) and the particle trajectory simulation with HYSPLYT (HYbrid Single-Particle Lagrangian Integrated Trajectory) (Kim et al., 2011) identified. Since the sand dune activity has been recognized as an essential indicator of the progressive desertification, it is important to establish the monitoring method for the variations of topographic properties by the dune activities such as local roughness. Thus it will provide the crucial data about the extent and the transition of sandy desert. For example, it is well known the aerodynamic roughness lengths Zo which can be driven from the specialized sensor such as POLDER (POLarization and Directionality of the Earth's Reflectances) is essential to understand desert dune characteristics. However, for the multi temporal observation of dune fields, the availability of data set to extract Zo is limited. Therefore, we employed MISR (Multi angle imaging Spectro Radiometer) image sequence to extract multi angle topographic parameters such as NDAI (Normalized Difference Angular Index) or the variation of radiance with the viewing geometry which are representing the characteristics of target desert topography instead of Zo. In our approach, NDAI were expanded to the all viewing angles and then compared over the target sandy desert and the surrounding land covers. It showed very strong consistencies according to the land cover type and especially over the dynamic dune fields. On the other hands, the variation of NDAIs of sandy desert combining with the metrological observations were

  12. Desert wetlands in the geologic record

    Science.gov (United States)

    Pigati, Jeff S.; Rech, Jason A.; Quade, Jay; Bright, Jordon; Edwards, L.; Springer, A.

    2014-01-01

    Desert wetlands support flora and fauna in a variety of hydrologic settings, including seeps, springs, marshes, wet meadows, ponds, and spring pools. Over time, eolian, alluvial, and fluvial sediments become trapped in these settings by a combination of wet ground conditions and dense plant cover. The result is a unique combination of clastic sediments, chemical precipitates, and organic matter that is preserved in the geologic record as ground-water discharge (GWD) deposits. GWD deposits contain information on the timing and magnitude of past changes in water-table levels and, therefore, are a potential source of paleohydrologic and paleoclimatic information. In addition, they can be important archeological and paleontological archives because desert wetlands provide reliable sources of fresh water, and thus act as focal points for human and faunal activities, in some of the world's harshest and driest lands. Here, we review some of the physical, sedimentological, and geochemical characteristics common to GWD deposits, and provide a contextual framework that researchers can use to identify and interpret geologic deposits associated with desert wetlands. We discuss several lines of evidence used to differentiate GWD deposits from lake deposits (they are commonly confused), and examine how various types of microbiota and depositional facies aid in reconstructing past environmental and hydrologic conditions. We also review how late Quaternary GWD deposits are dated, as well as methods used to investigate desert wetlands deeper in geologic time. We end by evaluating the strengths and limitations of hydrologic and climatic records derived from GWD deposits, and suggest several avenues of potential future research to further develop and utilize these unique and complex systems.

  13. CAMEL REARING IN CHOLISTAN DESERT OF PAKISTAN

    OpenAIRE

    I. ALI, M. SHAFIQ CHAUDHRY1 AND U. FAROOQ

    2009-01-01

    The camel is one of the typical and the best adopted animals of the desert, capable of enduring thirst and hunger for days and is the most patient of land animals. For desert nomads of Pakistani Cholistan, it is a beloved companion, a source of milk and meat, transport facility provider and a racing/dancing animal, thus, playing an important role in the socioeconomic uplift of the local community. Camels of Marrecha or Mahra breed are mainly used for riding and load carrying but may be traine...

  14. The evolution of deserts with climatic changes in China since 150 ka B.P.

    Institute of Scientific and Technical Information of China (English)

    董光荣; 陈惠忠; 王贵勇; 李孝泽; 邵亚军; 金炯

    1997-01-01

    According to the bioclimatic zones, dune mobility and the fabric characteristics of stratigraphic sedimentary facies, the deserts in China are divided into Eastern, Western, Central and Northwestern deserts. Based on the records of stratigraphical facies, climatic proxies, historical data, etc. in each desert region, the evolution of deserts with climatic changes in time and space since 150 ka B. P. in China are dealt with; then the evolution of deserts in relation to the glacial climatic fluctuations caused by solar radiation changes, underlying surface variation and their feedback mechanism is discussed through comparison with global records; finally, in consideration of global wanning due to increasing of greenhouse gases such as CO2, the possible tendency of the evolution of deserts and the climatic changes is discussed.

  15. Aeromycobiota of Western Desert of Egypt | Ismail | African Journal ...

    African Journals Online (AJOL)

    The prevalence of airborne mycobiota at six different regions of Western desert (5 regions) and Eastern desert (1) of Egypt was determined using the exposed-plate method. A total of 44 genera, 102 species and one variety in addition to some unidentified yeasts and dark sterile mycelia were collected. Of the above, only 5 ...

  16. Seedling establishment in a masting desert shrub parallels the pattern for forest trees

    Science.gov (United States)

    Meyer, Susan E.; Pendleton, Burton K.

    2015-05-01

    The masting phenomenon along with its accompanying suite of seedling adaptive traits has been well studied in forest trees but has rarely been examined in desert shrubs. Blackbrush (Coleogyne ramosissima) is a regionally dominant North American desert shrub whose seeds are produced in mast events and scatter-hoarded by rodents. We followed the fate of seedlings in intact stands vs. small-scale disturbances at four contrasting sites for nine growing seasons following emergence after a mast year. The primary cause of first-year mortality was post-emergence cache excavation and seedling predation, with contrasting impacts at sites with different heteromyid rodent seed predators. Long-term establishment patterns were strongly affected by rodent activity in the weeks following emergence. Survivorship curves generally showed decreased mortality risk with age but differed among sites even after the first year. There were no detectable effects of inter-annual precipitation variability or site climatic differences on survival. Intraspecific competition from conspecific adults had strong impacts on survival and growth, both of which were higher on small-scale disturbances, but similar in openings and under shrub crowns in intact stands. This suggests that adult plants preempted soil resources in the interspaces. Aside from effects on seedling predation, there was little evidence for facilitation or interference beneath adult plant crowns. Plants in intact stands were still small and clearly juvenile after nine years, showing that blackbrush forms cohorts of suppressed plants similar to the seedling banks of closed forests. Seedling banks function in the absence of a persistent seed bank in replacement after adult plant death (gap formation), which is temporally uncoupled from masting and associated recruitment events. This study demonstrates that the seedling establishment syndrome associated with masting has evolved in desert shrublands as well as in forests.

  17. [Academic stress, desertion, and retention strategies for students in higher education].

    Science.gov (United States)

    Suárez-Montes, Nancy; Díaz-Subieta, Luz B

    2015-04-01

    A systematic review was performed to specify the characteristics of academic stress that affect the mental health of the university population. To do this, recent publications regarding academic stress, student desertion, and retention strategies were examined. Throughout this text, we present the results of the review in terms of the definitions of academic stress, student desertion, and retention strategies. In the same way, we examine the interpretative models with regard to student desertion and approach retention strategies in higher education. We also review retention experiences of several other countries. In terms of Colombia, we present aspects related to student desertion and retention programs from the point of view of the National Ministry of Education and from the experience of some universities with consolidated programs.

  18. Experimental study on water transport observations of desert riparian forests in the lower reaches of the Tarim River in China.

    Science.gov (United States)

    Chen, Yaning; Li, Weihong; Zhou, Honghua; Chen, Yapeng; XinmingHao; Fu, Aihong; Ma, Jianxin

    2017-06-01

    Studying the water use processes of desert riparian vegetation in arid regions and analyzing the response and adaptation strategies of plants to drought stress are of great significance for developing ecological restoration measures. Based on field monitoring and test analyses of physiological ecological indicators of dominant species (Populus euphratica and Tamarix chinensis) in the desert riparian forest in the lower reaches of the Tarim River, the water relations of P. euphratica and T. chinensis under drought stress are discussed and some water use strategies put forward. The results show that (1) concerning plant water uptake, desert riparian forests depend mainly on groundwater to survive under long-term water stress. (2) Concerning plant water distribution, the survival of P. euphratica and nearby shallow root plants is mainly due to the hydraulic lift and water redistribution of P. euphratica under drought stress. (3) Concerning plant water transport, P. euphratica sustains the survival of competitive and advantageous branches by improving their ability to acquire water while restraining the growth of inferior branches. (4) Concerning plant transpiration, the sap flow curves of daily variations of P. euphratica and T. chinensis were wide-peak sin and narrower-peak respectively. T. chinensis has better environmental adaptability.

  19. Female offspring desertion and male-only care increase with natural and experimental increase in food abundance.

    Science.gov (United States)

    Eldegard, Katrine; Sonerud, Geir A

    2009-05-07

    In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a 1-year experimental study. Parents and offspring were fitted with radio-transmitters in order to reveal the parental care strategy (i.e. care or desert) of individual parents, and to keep track of the broods post-fledging. We found that 70 per cent of the females from non-experimental nests deserted, while their partner continued to care for their joint offspring alone. Desertion rate was positively related to natural prey population densities and body reserves of the male partner. In response to food supplementation, a larger proportion of the females deserted, and females deserted the offspring at an earlier age. Offspring survival during the post-fledging period tended to be lower in deserted than in non-deserted broods. We argue that the most important benefit of deserting may be remating (sequential polyandry).

  20. Effects of subsidized predators, resource variability, and human population density on desert tortoise populations in the Mojave Desert, USA

    Science.gov (United States)

    Esque, Todd C.; Nussear, Kenneth E.; Drake, K. Kristina; Walde, Andrew D.; Berry, Kristin H.; Averill-Murray, Roy C.; Woodman, A. Peter; Boarman, William I.; Medica, Phil A.; Mack, Jeremy S.; Heaton, Jill S.

    2010-01-01

    Understanding predator–prey relationships can be pivotal in the conservation of species. For 2 decades, desert tortoise Gopherus agassizii populations have declined, yet quantitative evidence regarding the causes of declines is scarce. In 2005, Ft. Irwin National Training Center, California, USA, implemented a translocation project including 2 yr of baseline monitoring of desert tortoises. Unusually high predation on tortoises was observed after translocation occurred. We conducted a retrospective analysis of predation and found that translocation did not affect the probability of predation: translocated, resident, and control tortoises all had similar levels of predation. However, predation rates were higher near human population concentrations, at lower elevation sites, and for smaller tortoises and females. Furthermore, high mortality rates were not limited to the National Training Center. In 2008, elevated mortality (as high as 43%) occurred throughout the listed range of the desert tortoise. Although no temporal prey base data are available for analysis from any of the study sites, we hypothesize that low population levels of typical coyote Canis latrans prey (i.e. jackrabbits Lepus californicus and other small animals) due to drought conditions influenced high predation rates in previous years. Predation may have been exacerbated in areas with high levels of subsidized predators. Many historical reports of increased predation, and our observation of a range-wide pattern, may indicate that high predation rates are more common than generally considered and may impact recovery of the desert tortoise throughout its range.

  1. Observed 20th century desert dust variability: impact on climate and biogeochemistry

    Directory of Open Access Journals (Sweden)

    N. M. Mahowald

    2010-11-01

    Full Text Available Desert dust perturbs climate by directly and indirectly interacting with incoming solar and outgoing long wave radiation, thereby changing precipitation and temperature, in addition to modifying ocean and land biogeochemistry. While we know that desert dust is sensitive to perturbations in climate and human land use, previous studies have been unable to determine whether humans were increasing or decreasing desert dust in the global average. Here we present observational estimates of desert dust based on paleodata proxies showing a doubling of desert dust during the 20th century over much, but not all the globe. Large uncertainties remain in estimates of desert dust variability over 20th century due to limited data. Using these observational estimates of desert dust change in combination with ocean, atmosphere and land models, we calculate the net radiative effect of these observed changes (top of atmosphere over the 20th century to be −0.14 ± 0.11 W/m2 (1990–1999 vs. 1905–1914. The estimated radiative change due to dust is especially strong between the heavily loaded 1980–1989 and the less heavily loaded 1955–1964 time periods (−0.57 ± 0.46 W/m2, which model simulations suggest may have reduced the rate of temperature increase between these time periods by 0.11 °C. Model simulations also indicate strong regional shifts in precipitation and temperature from desert dust changes, causing 6 ppm (12 PgC reduction in model carbon uptake by the terrestrial biosphere over the 20th century. Desert dust carries iron, an important micronutrient for ocean biogeochemistry that can modulate ocean carbon storage; here we show that dust deposition trends increase ocean productivity by an estimated 6% over the 20th century, drawing down an additional 4 ppm (8 PgC of carbon dioxide into the oceans. Thus, perturbations to desert dust over the 20th century inferred from observations are potentially important for climate and

  2. Observation of water and heat fluxes in the Badain Jaran desert, China

    NARCIS (Netherlands)

    Zhang, T.; Wen, J.; Su, Z.; Tian, H.; Zeng, Y.

    Badain Jaran Desert lie in the northwest of the Alashan plateau in western Inner Mongolia of China, between39o20'N to 41o30'N and 100oE to 104oE. It is the 4th largest desert in the world and the second largest desert in China, with an area of 49000 square kilometers and an altitude between 900 and

  3. Biparentally deserted offspring are viable in a species with intense sexual conflict over care.

    Science.gov (United States)

    Pogány, Ákos; Kosztolányi, András; Miklósi, Ádám; Komdeur, Jan; Székely, Tamás

    2015-07-01

    Desertion of clutch (or brood) by both parents often leads to breeding failure, since in vast majority of birds care by at least one parent is required for any young to fledge. Recent works in a highly polygamous passerine bird, the Eurasian penduline tit (Remiz pendulinus), suggest that biparental clutch desertion is due to intense sexual conflict over care. However, an alternative yet untested hypothesis for biparental desertion is low offspring viability so that the parents abandon the offspring that have poor prospect for survival. Here we test the latter hypothesis in a common garden experiment by comparing the viability of deserted and cared for eggs. We show that embryonic development does not differ between deserted and cared for eggs. Therefore, sexual conflict over care remains the best supported hypothesis for biparental clutch desertion in penduline tits. Our work points out that conflict over care is a potential - yet rarely considered - cause of biparental nest desertion, and a strong alternative for the traditional explanations of low offspring viability, human disturbance or deteriorating ambient environment. Apart from a handful of species, the intensity of sexual conflict has not been quantified, and we call for further studies to consider sexual conflict as a cause of nest desertion. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. CAMEL REARING IN CHOLISTAN DESERT OF PAKISTAN

    Directory of Open Access Journals (Sweden)

    I. ALI, M. SHAFIQ CHAUDHRY1 AND U. FAROOQ

    2009-05-01

    Full Text Available The camel is one of the typical and the best adopted animals of the desert, capable of enduring thirst and hunger for days and is the most patient of land animals. For desert nomads of Pakistani Cholistan, it is a beloved companion, a source of milk and meat, transport facility provider and a racing/dancing animal, thus, playing an important role in the socioeconomic uplift of the local community. Camels of Marrecha or Mahra breed are mainly used for riding and load carrying but may be trained for dancing or racing. Berella is another heavy and milch breed of camel famous for milk production and can produce upto 10-15 liters of milk per day. This breed is also suitable for draught purpose, though comparatively slow due to heavy body. The present paper also describes the traditional camel rearing system used by nomads of Cholistan desert. Some aspects of camel health, production, feeding, socio-economic values, marketing and some constraints and suggestions are also given so that the policy makers may consider them for the welfare of this animal.

  5. Pastoralist rock art in the Black Desert of Jordan

    OpenAIRE

    Brusgaard, N.O.

    2015-01-01

    This paper discusses the current problems that exist with the rock art research of the Black Desert in Jordan and presents some preliminary field results of the author’s research on the petroglyphs. It also explore the possibilities that the rock art affords to learn more about the elusive desert societies and the limitations about studying rock art in archaeologically unfamiliar territories.

  6. Hydrological indications of aeolian salts in mid-latitude deserts of ...

    Indian Academy of Sciences (India)

    Hydrological indications of aeolian salts in mid-latitude deserts of northwestern China. B Q Zhu. Supplementary data. Figure S1. Photograph views of Quaternary and modern sediments of aeolian and lacustrine/fluvial facies that consisted of clay and sand/silt sand alternations in the Taklamakan and Badanjilin Deserts.

  7. Mineral compositions and sources of the riverbed sediment in the desert channel of Yellow River.

    Science.gov (United States)

    Jia, Xiaopeng; Wang, Haibing

    2011-02-01

    The Yellow River flows through an extensive, aeolian desert area and extends from Xiaheyan, Ningxia Province, to Toudaoguai, Inner Mongolia Province, with a total length of 1,000 km. Due to the construction and operation of large reservoirs in the upstream of the Yellow River, most water and sediment from upstream were stored in these reservoirs, which leads to the declining flow in the desert channel that has no capability to scour large amount of input of desert sands from the desert regions. By analyzing and comparing the spatial distribution of weight percent of mineral compositions between sediment sources and riverbed sediment of the main tributaries and the desert channel of the Yellow River, we concluded that the coarse sediment deposited in the desert channel of the Yellow River were mostly controlled by the local sediment sources. The analyzed results of the Quartz-Feldspar-Mica (QFM) triangular diagram and the R-factor models of the coarse sediment in the Gansu reach and the desert channel of the Yellow River further confirm that the Ningxia Hedong desert and the Inner Mongolian Wulanbuhe and Kubuqi deserts are the main provenances of the coarse sediment in the desert channel of the Yellow River. Due to the higher fluidity of the fine sediment, they are mainly contributed by the local sediment sources and the tributaries that originated from the loess area of the upper reach of the Yellow River.

  8. Hidden Disadvantage: Asian American Unemployment and the Great Recession. EPI Issue Brief #277

    Science.gov (United States)

    Austin, Algernon

    2010-01-01

    Nationally, Asian Americans have the lowest unemployment rate of the major racial groups. But a closer look at unemployment by educational attainment shows a more complicated picture. Asian Americans with bachelor's degrees have a higher unemployment rate than whites with comparable education, but Asian American high school dropouts are more…

  9. Modernity in Two Great American Writers' Vision: Ernest Miller Hemingway and Scott Fitzgerald

    Science.gov (United States)

    Keshmiri, Fahimeh; Darzikola, Shahla Sorkhabi

    2016-01-01

    Scott Fitzgerald and Ernest Hemingway, American memorable novelists have had philosophic ideas about modernity. In fact their idea about existential interests of American, and the effects of American system on society, is mirrored in their creative works. All through his early works, Fitzgerald echoes the existential center of his era. Obviously,…

  10. A demographic approach to study effects of climate change in desert plants

    Science.gov (United States)

    Salguero-Gómez, Roberto; Siewert, Wolfgang; Casper, Brenda B.; Tielbörger, Katja

    2012-01-01

    Desert species respond strongly to infrequent, intense pulses of precipitation. Consequently, indigenous flora has developed a rich repertoire of life-history strategies to deal with fluctuations in resource availability. Examinations of how future climate change will affect the biota often forecast negative impacts, but these—usually correlative—approaches overlook precipitation variation because they are based on averages. Here, we provide an overview of how variable precipitation affects perennial and annual desert plants, and then implement an innovative, mechanistic approach to examine the effects of precipitation on populations of two desert plant species. This approach couples robust climatic projections, including variable precipitation, with stochastic, stage-structured models constructed from long-term demographic datasets of the short-lived Cryptantha flava in the Colorado Plateau Desert (USA) and the annual Carrichtera annua in the Negev Desert (Israel). Our results highlight these populations' potential to buffer future stochastic precipitation. Population growth rates in both species increased under future conditions: wetter, longer growing seasons for Cryptantha and drier years for Carrichtera. We determined that such changes are primarily due to survival and size changes for Cryptantha and the role of seed bank for Carrichtera. Our work suggests that desert plants, and thus the resources they provide, might be more resilient to climate change than previously thought. PMID:23045708

  11. Stream hierarchy defines riverscape genetics of a North American desert fish.

    Science.gov (United States)

    Hopken, Matthew W; Douglas, Marlis R; Douglas, Michael E

    2013-02-01

    Global climate change is apparent within the Arctic and the south-western deserts of North America, with record drought in the latter reflected within 640,000 km(2) of the Colorado River Basin. To discern the manner by which natural and anthropogenic drivers have compressed Basin-wide fish biodiversity, and to establish a baseline for future climate effects, the Stream Hierarchy Model (SHM) was employed to juxtapose fluvial topography against molecular diversities of 1092 Bluehead Sucker (Catostomus discobolus). MtDNA revealed three geomorphically defined evolutionarily significant units (ESUs): Bonneville Basin, upper Little Colorado River and the remaining Colorado River Basin. Microsatellite analyses (16 loci) reinforced distinctiveness of the Bonneville Basin and upper Little Colorado River, but subdivided the Colorado River Basin into seven management units (MUs). One represents a cline of three admixed gene pools comprising the mainstem and its lower-gradient tributaries. Six others are not only distinct genetically but also demographically (i.e. migrants/generation <9.7%). Two of these (i.e. Grand Canyon and Canyon de Chelly) are defined by geomorphology, two others (i.e. Fremont-Muddy and San Raphael rivers) are isolated by sharp declivities as they drop precipitously from the west slope into the mainstem Colorado/Green rivers, another represents an isolated impoundment (i.e. Ringdahl Reservoir), while the last corresponds to a recognized subspecies (i.e. Zuni River, NM). Historical legacies of endemic fishes (ESUs) and their evolutionary potential (MUs) are clearly represented in our data, yet their arbiter will be the unrelenting natural and anthropogenic water depletions that will precipitate yet another conservation conflict within this unique but arid region. © 2012 Blackwell Publishing Ltd.

  12. Vegetation - Central Mojave Desert [ds166

    Data.gov (United States)

    California Natural Resource Agency — The Department of Defense and the other desert managers are developing and organizing scientific information needed to better manage the natural resources of the...

  13. The Ocean deserts:salt budgets of northern subtropical oceans and their

    KAUST Repository

    Carton, Jim

    2011-04-09

    The Ocean deserts: salt budgets of northern subtropical oceans and their relationship to climate variability The high salinity near surface pools of the subtropical oceans are the oceanic deserts, with high levels of evaporation and low levels of precip

  14. Mapping of Grocery Stores in Slovak Countryside in Context of Food Deserts

    Directory of Open Access Journals (Sweden)

    Kristína Bilková

    2015-01-01

    Full Text Available The paper is focused on mapping grocery stores in the Slovak countryside with an emphasis on identifying potential food deserts in rural areas. Grocery stores are analyzed in the time period 2001–2011. Food deserts in rural areas are identified by two accessibility measures. The results show the development of food retailing in the Slovak countryside and in potentially threatened localities which can be defined as food deserts.

  15. Soil seed bank in different habitats of the Eastern Desert of Egypt.

    Science.gov (United States)

    Gomaa, Nasr H

    2012-04-01

    The floristic composition and species diversity of the germinable soil seed bank were studied in three different habitats (desert salinized land, desert wadi, and reclaimed land) in the Eastern Desert of Egypt. Moreover, the degree of similarity between the seed bank and the above-ground vegetation was determined. The seed bank was studied in 40 stands representing the three habitats. Ten soil samples (each 25 × 20 cm and 5 cm depth) were randomly taken per stand. The seed bank was investigated by the seedling emergence method. Some 61 species belonging to 21 families and 54 genera were identified in the germinable seed bank. The recorded species include 43 annuals and 18 perennials. Ordination of stands by Detrended Correspondence Analysis (DCA) indicates that the stands of the three habitats are markedly distinguishable and show a clear pattern of segregation on the ordination planes. This indicates variations in the species composition among habitats. The results also demonstrate significant associations between the floristic composition of the seed bank and edaphic factors such as CaCO3, electrical conductivity, organic carbon and soil texture. The reclaimed land has the highest values of species richness, Shannon-index of diversity and the density of the germinable seed bank followed by the habitats of desert wadi and desert salinized land. Motyka's similarity index between the seed bank and the above-ground vegetation is significantly higher in reclaimed land (75.1%) compared to desert wadi (38.4%) and desert salinized land (36.5%).

  16. Desert farming benefits from microbial potential in arid soils and promotes diversity and plant health.

    Directory of Open Access Journals (Sweden)

    Martina Köberl

    Full Text Available BACKGROUND: To convert deserts into arable, green landscapes is a global vision, and desert farming is a strong growing area of agriculture world-wide. However, its effect on diversity of soil microbial communities, which are responsible for important ecosystem services like plant health, is still not known. METHODOLOGY/PRINCIPAL FINDINGS: We studied the impact of long-term agriculture on desert soil in one of the most prominent examples for organic desert farming in Sekem (Egypt. Using a polyphasic methodological approach to analyse microbial communities in soil as well as associated with cultivated plants, drastic effects caused by 30 years of agriculture were detected. Analysing bacterial fingerprints, we found statistically significant differences between agricultural and native desert soil of about 60%. A pyrosequencing-based analysis of the 16S rRNA gene regions showed higher diversity in agricultural than in desert soil (Shannon diversity indices: 11.21/7.90, and displayed structural differences. The proportion of Firmicutes in field soil was significantly higher (37% than in the desert (11%. Bacillus and Paenibacillus play the key role: they represented 96% of the antagonists towards phytopathogens, and identical 16S rRNA sequences in the amplicon library and for isolates were detected. The proportion of antagonistic strains was doubled in field in comparison to desert soil (21.6%/12.4%; disease-suppressive bacteria were especially enriched in plant roots. On the opposite, several extremophilic bacterial groups, e.g., Acidimicrobium, Rubellimicrobium and Deinococcus-Thermus, disappeared from soil after agricultural use. The N-fixing Herbaspirillum group only occurred in desert soil. Soil bacterial communities were strongly driven by the a-biotic factors water supply and pH. CONCLUSIONS/SIGNIFICANCE: After long-term farming, a drastic shift in the bacterial communities in desert soil was observed. Bacterial communities in agricultural

  17. Palynology in a polar desert, eastern North Greenland

    DEFF Research Database (Denmark)

    Funder, Svend Visby; Abrahamsen, Niels

    1988-01-01

    history back to c. 7,000 years calBP (6,000 years convBP) in this·extreme environment, which presents the coldest thermal regime where vascular plants can grow. The diagram shows that polar desert developed from sparse high arctic tundra at c. 4,300 years calBP (3,900 years convBP), owing...... to reduced summer heat. Also adjacent parts of high arctic Greenland, Canada and Svalbard suffered environmental decline, and polar deserts- presently restricted to a narrow fringe of land at the shores of the Arctic Ocean-were even more restricted before this time. Like other arctic vegetation types, polar...... desert is highly sensitive to summer temperatures, and its southern limit coincides with the isotherm for mean July temperatures of 3.5'C, A comparison with the Northwest European ice-age pollen record shows no evidence of summers as cold as those now prevailing in the extreme north, and the results...

  18. Throughfall and its spatial variability beneath xerophytic shrub canopies within water-limited arid desert ecosystems

    Science.gov (United States)

    Zhang, Ya-feng; Wang, Xin-ping; Hu, Rui; Pan, Yan-xia

    2016-08-01

    Throughfall is known to be a critical component of the hydrological and biogeochemical cycles of forested ecosystems with inherently temporal and spatial variability. Yet little is understood concerning the throughfall variability of shrubs and the associated controlling factors in arid desert ecosystems. Here we systematically investigated the variability of throughfall of two morphological distinct xerophytic shrubs (Caragana korshinskii and Artemisia ordosica) within a re-vegetated arid desert ecosystem, and evaluated the effects of shrub structure and rainfall characteristics on throughfall based on heavily gauged throughfall measurements at the event scale. We found that morphological differences were not sufficient to generate significant difference (P < 0.05) in throughfall between two studied shrub species under the same rainfall and meteorological conditions in our study area, with a throughfall percentage of 69.7% for C. korshinskii and 64.3% for A. ordosica. We also observed a highly variable patchy pattern of throughfall beneath individual shrub canopies, but the spatial patterns appeared to be stable among rainfall events based on time stability analysis. Throughfall linearly increased with the increasing distance from the shrub base for both shrubs, and radial direction beneath shrub canopies had a pronounced impact on throughfall. Throughfall variability, expressed as the coefficient of variation (CV) of throughfall, tended to decline with the increase in rainfall amount, intensity and duration, and stabilized passing a certain threshold. Our findings highlight the great variability of throughfall beneath the canopies of xerophytic shrubs and the time stability of throughfall pattern among rainfall events. The spatially heterogeneous and temporally stable throughfall is expected to generate a dynamic patchy distribution of soil moisture beneath shrub canopies within arid desert ecosystems.

  19. [Spatial change of the grain-size of aeolian sediments in Qira oasis-desert ecotone, Northwest China].

    Science.gov (United States)

    Lin, Yong Chong; Xu, Li Shuai

    2017-04-18

    In order to understand the environmental influence of oasis-desert ecotone to oasis ecological system, we comparatively analyzed the grain size characteristics of various aeolian sediments, including the sediments in oasis-desert ecotone, shelterbelt and the inside oasis and in Qira River valley. The results showed that the grain size characteristics (including grain-size distribution curve, grain size parameters, and content of different size classes) of sediments in the oasis-desert ecotone were consistent along the prevailing wind direction with a grain-size range of 0.3-200 μm and modal size of 67 μm. All of the sediments were good sorting and mainly composed of suspension components and saltation components, but not denatured saltation and creeping components (>200 μm). They were typically aeolian deposits being short-range transported. The grain sizes of sediments in oasis-desert ecotone were smaller than that in the material sources of Qira River valley and desert (0.3-800 μm), but very similar to those of the modern aeolian deposits in oasis-desert ecotone, shelterbelt and the inside oasis. The denatured saltation and creep components (>200 μm) were suppressed to transport into oasis-desert ecotone because of the high vegetation cover in oasis-desert ecotone. Therefore, like the shelterbelts, the oasis-desert ecotone could also block the invasion of desert. They safeguarded the oasis ecological environment together.

  20. Desert Net-Structure and Aims of an International Network for Desertification Research

    International Nuclear Information System (INIS)

    Akhtar-Schuster, M.; San Juan Mesonada, C.

    2009-01-01

    Desert Net://www.european-desert net.eu) is an interdisciplinary scientific network which was established in October 2006 at the UN premises in Bonn, Germany, by a group of international scientists. The network strives to generate and enhance scientific knowledge and understanding of the biophysical and socio-economic processes of desertification. This international scientific network provides an international platform for scientifically based discussions and exchange of ideas, addressing knowledge gaps, and identifying research areas. Desert Net is also a think tank community which identifies issues and priorities for the sustainable development of dry lands. the paper outlines the current role of Desert Net in the international scientific community and it delineates its role to strengthen the Science/Policy Interface. (Author) 2 refs.

  1. Cytogeography of Larrea tridentata at the Chihuahuan-Sonoran Desert ecotone

    Science.gov (United States)

    Robert G. Laport; Robert L.. Minckley

    2013-01-01

    The long separation of the Chihuahuan and Sonoran Deserts is reflected in the high species richness and endemism of their floras. Although many endemic species from both deserts reach their distributional limits where the Sierra Madre Occidental massif fragments into smaller mountain complexes in northern Mexico and adjoining areas of the United States, indicator...

  2. MX Siting Investigation. Gravity Survey - Sevier Desert Valley, Utah.

    Science.gov (United States)

    1981-01-24

    Cheyenne, Wyoming. DMAHTC reduces the data to Simple Bouguer Anomaly (see Section A1.4, Appendix Al.0). The Defense Mapping Agency Aerospace Center...Desert Valley, Utah ......... 2 2 Topographic Setting - Sevier Desert Valley, Utah . 3 LIST OF DRAWINGS Drawing Number 1 Complete Bouguer Anomaly...gravity stations were distributed throughout the valley at an approxi- mate interval of 1.4 miles (2.3 km). Drawing 1 is a Complete Bouguer Anomaly

  3. Desert springs: deep phylogeographic structure in an ancient endemic crustacean (Phreatomerus latipes.

    Directory of Open Access Journals (Sweden)

    Michelle T Guzik

    Full Text Available Desert mound springs of the Great Artesian Basin in central Australia maintain an endemic fauna that have historically been considered ubiquitous throughout all of the springs. Recent studies, however, have shown that several endemic invertebrate species are genetically highly structured and contain previously unrecognised species, suggesting that individuals may be geographically 'stranded in desert islands'. Here we further tested the generality of this hypothesis by conducting genetic analyses of the obligate aquatic phreatoicid isopod Phreatomerus latipes. Phylogenetic and phylogeographic relationships amongst P. latipes individuals were examined using a multilocus approach comprising allozymes and mtDNA sequence data. From the Lake Eyre region in South Australia we collected data for 476 individuals from 69 springs for the mtDNA gene COI; in addition, allozyme electrophoresis was conducted on 331 individuals from 19 sites for 25 putative loci. Phylogenetic and population genetic analyses showed three major clades in both allozyme and mtDNA data, with a further nine mtDNA sub-clades, largely supported by the allozymes. Generally, each of these sub-clades was concordant with a traditional geographic grouping known as spring complexes. We observed a coalescent time between ∼2-15 million years ago for haplotypes within each of the nine mtDNA sub-clades, whilst an older total time to coalescence (>15 mya was observed for the three major clades. Overall we observed that multiple layers of phylogeographic history are exemplified by Phreatomerus, suggesting that major climate events and their impact on the landscape have shaped the observed high levels of diversity and endemism. Our results show that this genus reflects a diverse fauna that existed during the early Miocene and appears to have been regionally restricted. Subsequent aridification events have led to substantial contraction of the original habitat, possibly over repeated Pleistocene

  4. Reestablishing healthy food retail: changing the landscape of food deserts.

    Science.gov (United States)

    Karpyn, Allison; Young, Candace; Weiss, Stephanie

    2012-02-01

    The term "food desert" was formally introduced into the lexicon in 1995 and has come to describe areas with limited access to affordable nutritious foods, particularly areas in lower-income neighborhoods. The definition has led to the development of national and regional maps that focus efforts on equity in food access. Recognition of food deserts also marks a strategic change in public health's approach to obesity prevention. Today's emphasis on prevention has shifted away from individual responsibility to the role of the environment in health promotion. A number of solutions are underway to address food deserts, including public–private financing programs, industry commitments, as well as local and regional efforts to put healthy food within reach. The promise of financing programs to facilitate development of healthy food markets in underserved communities is rooted in their potential to alleviate the grocery gap and address underlying environmental contributors to obesity and diet-related diseases, such as obesity and diabetes. As food desert mapping and related interventions expand, there remains a need for ongoing investigation of impacts and the mechanisms by which impacts are achieved.

  5. Liquid Water Restricts Habitability in Extreme Deserts

    Science.gov (United States)

    Cockell, Charles S.; Brown, Sarah; Landenmark, Hanna; Samuels, Toby; Siddall, Rebecca; Wadsworth, Jennifer

    2017-04-01

    Liquid water is a requirement for biochemistry, yet under some circumstances it is deleterious to life. Here, we show that liquid water reduces the upper temperature survival limit for two extremophilic photosynthetic microorganisms (Gloeocapsa and Chroococcidiopsis spp.) by greater than 40°C under hydrated conditions compared to desiccated conditions. Under hydrated conditions, thermal stress causes protein inactivation as shown by the fluorescein diacetate assay. The presence of water was also found to enhance the deleterious effects of freeze-thaw in Chroococcidiopsis sp. In the presence of water, short-wavelength UV radiation more effectively kills Gloeocapsa sp. colonies, which we hypothesize is caused by factors including the greater penetration of UV radiation into hydrated colonies compared to desiccated colonies. The data predict that deserts where maximum thermal stress or irradiation occurs in conjunction with the presence of liquid water may be less habitable to some organisms than more extreme arid deserts where organisms can dehydrate prior to being exposed to these extremes, thus minimizing thermal and radiation damage. Life in extreme deserts is poised between the deleterious effects of the presence and the lack of liquid water.

  6. Survival of a planet in short-period Neptunian desert under effect of photoevaporation

    Science.gov (United States)

    Ionov, Dmitry E.; Pavlyuchenkov, Yaroslav N.; Shematovich, Valery I.

    2018-06-01

    Despite the identification of a great number of Jupiter-like and Earth-like planets at close-in orbits, the number of `hot Neptunes' - the planets with 0.6-18 times of Neptune mass and orbital periods less than 3 d - turned out to be very small. The corresponding region in the mass-period distribution was assigned as the `short-period Neptunian desert'. The common explanation of this fact is that the gaseous planet with few Neptune masses would not survive in the vicinity of host star due to intensive atmosphere outflow induced by heating from stellar radiation. To check this hypothesis, we performed numerical simulations of atmosphere dynamics for a hot Neptune. We adopt the previously developed self-consistent 1D model of hydrogen-helium atmosphere with suprathermal electrons accounted. The mass-loss rates as a function of orbital distances and stellar ages are presented. We conclude that the desert of short-period Neptunes could not be entirely explained by evaporation of planet atmosphere caused by the radiation from a host star. For the less massive Neptune-like planet, the estimated upper limits of the mass-loss may be consistent with the photoevaporation scenario, while the heavier Neptune-like planets could not lose the significant mass through this mechanism. We also found the significant differences between our numerical results and widely used approximate estimates of the mass-loss.

  7. The economics of hybrid power systems for sustainable desert agriculture in Egypt

    DEFF Research Database (Denmark)

    Kamel, S.M.; Dahl, C.

    2005-01-01

    Egypt has embarked on an ambitious desert land reclamation program in order to increase total food production. Energy planners for these desert agriculture locations have chosen diesel generation power technology because minimization of the initial capital cost of a power supply system is their top...... priority. This heavy reliance on diesel generation has negative effects on the surrounding environment including soil, groundwater, and air pollution. Although good solar and wind resource prospects exist for the use of cleaner hybrid power systems in certain desert locations, little research has been done...... to investigate the economic potential of such systems in Egypt’s desert agriculture sector. Using optimization software, we assess the economics of hybrid power systems versus the present diesel generation technology in a remote agricultural development area. We also consider the emission reduction advantages...

  8. Winter precipitation and fire in the Sonoran Desert

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, G.F.; Vint, M.K.

    1987-01-01

    Historical fire and climate records from the Arizona Upland portion of the Tonto National forest were used to test the hypothesis that fires burn larger areas in the Sonoran Desert after two wet winters than after one. We found that many more hectares burn in years following two winters that are wetter than normal, than during any other years. We agree with other ecologists, that desert fire occurrence is probably related to increased production of winter annual plants, and we suggest ways that the relationship may be clarified.

  9. Naturalisation, Desert, and the Symbolic Meaning of Citizenship

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2012-01-01

    of naturalisation requirements as involving notions of desert and asks what these developments imply about the meaning of citizenship. Naturalisation marks the boundary of society understood as a political community, i.e. a civic rather than territorial boundary. How this boundary is policed and on the basis...... that the introduction of naturalisation tests and other desert-based naturalisation requirements imply that citizenship comes to have different symbolic meanings for native born citizens and naturalised citizens because such requirements distinguish between volitional or ‘earned’ and ascriptive or ‘natural’ citizenship...

  10. The diverse impacts of the great recession

    OpenAIRE

    Makoto Nakajima

    2013-01-01

    The Great Recession had a large negative impact on the U.S. economy. Asset prices, most notably stock and house prices, declined substantially, resulting in a loss in wealth for many American households. In this article, Makoto Nakajima documents how diverse households were affected in a variety of dimensions during the Great Recession, in particular between 2007 and 2009, using newly available data from the 2007-2009 Survey of Consumer Finances. He discusses why it is important to look at th...

  11. Limited production of sulfate and nitrate on front-associated dust storm particles moving from desert to distant populated areas in northwestern China

    Science.gov (United States)

    Wu, Feng; Zhang, Daizhou; Cao, Junji; Guo, Xiao; Xia, Yao; Zhang, Ting; Lu, Hui; Cheng, Yan

    2017-12-01

    Sulfate and nitrate compounds can greatly increase the hygroscopicity of mineral particles in the atmosphere and consequently alter the particles' physical and chemical properties. Their uptake on long-distance-transported Asian dust particles within mainland China has been reported to be substantial in previous studies, but the production was very inefficient in other studies. We compared these two salts in particles collected from a synoptic-scale, mid-latitude, cyclone-induced dust storm plume at the Tengger Desert (38.79° N, 105.38° E) and in particles collected in a postfrontal dust plume at an urban site in Xi'an (34.22° N, 108.87° E) when a front-associated dust storm from the Tengger Desert arrived there approximately 700 km downwind. The results showed that the sulfate concentration was not considerably different at the two sites, while the nitrate concentration was slightly larger at the urban site than that at the desert site. The estimated nitrate production rate was 4-5 ng µg-1 of mineral dust per day, which was much less than that in polluted urban air. The adiabatic process of the dust-loading air was suggested to be the reason for the absence of sulfate formation, and the uptake of background HNO3 was suggested to be the reason for the small nitrate production. According to our investigation of the published literature, the significant sulfate and nitrate in dust-storm-associated samples within the continental atmosphere reported in previous studies cannot be confirmed as actually produced on desert dust particles; the contribution from locally emitted and urban mineral particles or from soil-derived sulfate was likely substantial because the weather conditions in those studies indicated that the collection of the samples was started before dust arrival, or the air from which the samples were collected was a mixture of desert dust and locally emitted mineral particles. These results suggest that the production of nitrate and sulfate on dust

  12. Limited production of sulfate and nitrate on front-associated dust storm particles moving from desert to distant populated areas in northwestern China

    Directory of Open Access Journals (Sweden)

    F. Wu

    2017-12-01

    Full Text Available Sulfate and nitrate compounds can greatly increase the hygroscopicity of mineral particles in the atmosphere and consequently alter the particles' physical and chemical properties. Their uptake on long-distance-transported Asian dust particles within mainland China has been reported to be substantial in previous studies, but the production was very inefficient in other studies. We compared these two salts in particles collected from a synoptic-scale, mid-latitude, cyclone-induced dust storm plume at the Tengger Desert (38.79° N, 105.38° E and in particles collected in a postfrontal dust plume at an urban site in Xi'an (34.22° N, 108.87° E when a front-associated dust storm from the Tengger Desert arrived there approximately 700 km downwind. The results showed that the sulfate concentration was not considerably different at the two sites, while the nitrate concentration was slightly larger at the urban site than that at the desert site. The estimated nitrate production rate was 4–5 ng µg−1 of mineral dust per day, which was much less than that in polluted urban air. The adiabatic process of the dust-loading air was suggested to be the reason for the absence of sulfate formation, and the uptake of background HNO3 was suggested to be the reason for the small nitrate production. According to our investigation of the published literature, the significant sulfate and nitrate in dust-storm-associated samples within the continental atmosphere reported in previous studies cannot be confirmed as actually produced on desert dust particles; the contribution from locally emitted and urban mineral particles or from soil-derived sulfate was likely substantial because the weather conditions in those studies indicated that the collection of the samples was started before dust arrival, or the air from which the samples were collected was a mixture of desert dust and locally emitted mineral particles. These results suggest that the

  13. Ophiolitic basement to the Great Valley forearc basin, California, from seismic and gravity data: Implications for crustal growth at the North American continental margin

    Science.gov (United States)

    Godfrey, N.J.; Beaudoin, B.C.; Klemperer, S.L.; Levander, A.; Luetgert, J.; Meltzer, A.; Mooney, W.; Tréhu, A.

    1997-01-01

    The nature of the Great Valley basement, whether oceanic or continental, has long been a source of controversy. A velocity model (derived from a 200-km-long east-west reflection-refraction profile collected south of the Mendocino triple junction, northern California, in 1993), further constrained by density and magnetic models, reveals an ophiolite underlying the Great Valley (Great Valley ophiolite), which in turn is underlain by a westward extension of lower-density continental crust (Sierran affinity material). We used an integrated modeling philosophy, first modeling the seismic-refraction data to obtain a final velocity model, and then modeling the long-wavelength features of the gravity data to obtain a final density model that is constrained in the upper crust by our velocity model. The crustal section of Great Valley ophiolite is 7-8 km thick, and the Great Valley ophiolite relict oceanic Moho is at 11-16 km depth. The Great Valley ophiolite does not extend west beneath the Coast Ranges, but only as far as the western margin of the Great Valley, where the 5-7-km-thick Great Valley ophiolite mantle section dips west into the present-day mantle. There are 16-18 km of lower-density Sierran affinity material beneath the Great Valley ophiolite mantle section, such that a second, deeper, "present-day" continental Moho is at about 34 km depth. At mid-crustal depths, the boundary between the eastern extent of the Great Valley ophiolite and the western extent of Sierran affinity material is a near-vertical velocity and density discontinuity about 80 km east of the western margin of the Great Valley. Our model has important implications for crustal growth at the North American continental margin. We suggest that a thick ophiolite sequence was obducted onto continental material, probably during the Jurassic Nevadan orogeny, so that the Great Valley basement is oceanic crust above oceanic mantle vertically stacked above continental crust and continental mantle.

  14. Are Wildlife Detector Dogs or People Better at Finding Desert Tortoises (Gopherus Agassizii)?

    National Research Council Canada - National Science Library

    Nussear, Kenneth E; Esque, Todd C; Heaton, Jill S; Cablk, Mary E; Drake, Kristina K; Valentin, Cindee; Yee, Julie L; Medica, Philip A

    2008-01-01

    .... Recent studies highlight the effectiveness of trained detector dogs to locate wildlife during field surveys, including Desert Tortoises in a semi-natural setting. Desert Tortoises (Gopherus agassizii...

  15. Distance to Store, Food Prices, and Obesity in Urban Food Deserts

    Science.gov (United States)

    Ghosh-Dastidar, Bonnie; Cohen, Deborah; Hunter, Gerald; Zenk, Shannon N.; Huang, Christina; Beckman, Robin; Dubowitz, Tamara

    2014-01-01

    Background Lack of access to healthy foods may explain why residents of low-income neighborhoods and African Americans in the U.S. have high rates of obesity. The findings on where people shop and how that may influence health are mixed. However, multiple policy initiatives are underway to increase access in communities that currently lack healthy options. Few studies have simultaneously measured obesity, distance, and prices of the store used for primary food shopping. Purpose To examine the relationship among distance to store, food prices, and obesity. Methods The Pittsburgh Hill/Homewood Research on Eating, Shopping, and Health study conducted baseline interviews with 1,372 households between May and December 2011 in two low-income, majority African American neighborhoods without a supermarket. Audits of 16 stores where participants reported doing their major food shopping were conducted. Data were analyzed between February 2012 and February 2013. Results Distance to store and prices were positively associated with obesity (pfood prices were jointly modeled, only prices remained significant (pjunk foods relative to healthy foods. Conclusions Placing supermarkets in food deserts to improve access may not be as important as simultaneously offering better prices for healthy foods relative to junk foods, actively marketing healthy foods, and enabling consumers to resist the influence of junk food marketing. PMID:25217097

  16. Are wildlife detector dogs or people better at finding Desert Tortoises (Gopherus agassizii)?

    Science.gov (United States)

    Nussear, K.E.; Esque, T.C.; Heaton, J.S.; Cablk, Mary E.; Drake, K.K.; Valentin, C.; Yee, J.L.; Medica, P.A.

    2008-01-01

    Our ability to study threatened and endangered species depends on locating them readily in the field. Recent studies highlight the effectiveness of trained detector dogs to locate wildlife during field surveys, including Desert Tortoises in a semi-natural setting. Desert Tortoises (Gopherus agassizii) are cryptic and difficult to detect during surveys, especially the smaller size classes. We conducted comparative surveys to determine whether human or detector dog teams were more effective at locating Desert Tortoises in the wild. We compared detectability of Desert Tortoises and the costs to deploy human and dog search teams. Detectability of tortoises was not statistically different for either team, and was estimated to be approximately 70% (SE = 5%). Dogs found a greater proportion of tortoises located in vegetation than did humans. The dog teams finished surveys 2.5 hours faster than the humans on average each day. The human team cost was approximately $3,000 less per square kilometer sampled. Dog teams provided a quick and effective method for surveying for adult Desert Tortoises; however, we were unable to determine-their effectiveness at locating smaller size classes. Detection of smaller size classes during surveys would improve management of the species and should be addressed by future research using Desert Tortoise detector dogs.

  17. Concentration of plutonium in desert plants from contaminated area

    International Nuclear Information System (INIS)

    Xu Hui; Jin Yuren; Tian Mei; Li Weiping; Zeng Ke; Wang Yaoqin; Wang Yu

    2012-01-01

    The investigation of plutonium in desert plants from contaminated sites contributes to the evaluation of its pollution situation and to the survey of plutonium hyper accumulator. The concentration of 239 Pu in desert plants collected from a contaminated site was determined, and the influence factors were studied. The concentration of 239 Pu in plants was (1.8±4.9) Bq/kg in dry weight, and it means that the plants were contaminated, moreover, the resuspension results in dramatic plutonium pollution of plant surface. The concentration of plutonium in plants depends on species, live stages and the content of plutonium in the rhizosphere soil. The concentration of plutonium in herbage is higher than that in woody plant, and for the seven species of desert plants investigated, it decreases in the order of Hexinia polydichotoma, Phragmites australis, Halostashys caspica, Halogeton arachnoideus, Lycium ruthenicum, Tamarix hispida and Calligonum aphyllum. (authors)

  18. Zoogeography of the San Andreas Fault system: Great Pacific Fracture Zones correspond with spatially concordant phylogeographic boundaries in western North America.

    Science.gov (United States)

    Gottscho, Andrew D

    2016-02-01

    The purpose of this article is to provide an ultimate tectonic explanation for several well-studied zoogeographic boundaries along the west coast of North America, specifically, along the boundary of the North American and Pacific plates (the San Andreas Fault system). By reviewing 177 references from the plate tectonics and zoogeography literature, I demonstrate that four Great Pacific Fracture Zones (GPFZs) in the Pacific plate correspond with distributional limits and spatially concordant phylogeographic breaks for a wide variety of marine and terrestrial animals, including invertebrates, fish, amphibians, reptiles, birds, and mammals. These boundaries are: (1) Cape Mendocino and the North Coast Divide, (2) Point Conception and the Transverse Ranges, (3) Punta Eugenia and the Vizcaíno Desert, and (4) Cabo Corrientes and the Sierra Transvolcanica. However, discussion of the GPFZs is mostly absent from the zoogeography and phylogeography literature likely due to a disconnect between biologists and geologists. I argue that the four zoogeographic boundaries reviewed here ultimately originated via the same geological process (triple junction evolution). Finally, I suggest how a comparative phylogeographic approach can be used to test the hypothesis presented here. © 2014 Cambridge Philosophical Society.

  19. Clean power from deserts. The DESERTEC concept for energy, water and climate security

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    The main challenge for the future is to reclaim energy from renewable and clean sources in environmentally compatible ways. Here the deserts of the earth can play a key role. They receive about 700 times more energy from the sun than humankind consumes by burning fossil fuels, day by day. Deserts are the places with the best solar radiation conditions and with the least possible impact of collector deployment onto the biosphere on earth. In deserts, clean power can be produced by solar thermal power plants (CSP) in a truly sustainable way and at any volume of conceivable demand. Power can be transmitted with low losses by high voltage direct current (HVDC) lines to more than 90% of the world's population. This gives the deserts a new role: Together with the many other forms of accessible renewable energy the newly utilized desert would enable us to replace fossil fuels and thus end the ongoing destruction of our natural living conditions. To put this into practice, countries with deserts, countries with high energy demand and countries with technology competence must cooperate. This is an opportunity for the Mediterranean riparian regions of Europe, the Middle East and North Africa (EUMENA) to form a community for energy, water and climate security. With the political will, EUMENA countries could now launch 'EUMENA-DESERTEC' Program, to bring humankind back into balance with its environment, by putting deserts and technology into service for energy, water and climate security. This would be an important step towards creating a truly sustainable civilization.

  20. Water Sources for Cyanobacteria Below Desert Rocks in the Negev Desert Determined by Conductivity

    Science.gov (United States)

    McKay, Christopher P.

    2016-01-01

    We present year round meteorological and conductivity measurements of colonized hypolithic rocks in the Arava Valley, Negev Desert, Israel. The data indicate that while dew is common in the Negev it is not an important source of moisture for hypolithic organisms at this site. The dominance of cyanobacteria in the hypolithic community are consistent with predictions that cyanobacteria are confined to habitats supplied by rain. To monitor the presence of liquid water under the small Negev rocks we developed and tested a simple field conductivity system based on two wires placed about 0.5 cm apart. Based on 21 replicates recorded for one year in the Negev we conclude that in natural rains (0.25 mm to 6 mm) the variability between sensor readings is between 20 and 60% decreasing with increasing rain amount. We conclude that the simple small electrical conductivity system described here can be used effectively to monitor liquid water levels in lithic habitats. However, the natural variability of these sensors indicates that several replicates should be deployed. The results and method presented have use in arid desert reclamation programs.

  1. A mechanistic modeling and data assimilation framework for Mojave Desert ecohydrology

    Science.gov (United States)

    Ng, Gene-Hua Crystal; Bedford, David R.; Miller, David M.

    2014-06-01

    This study demonstrates and addresses challenges in coupled ecohydrological modeling in deserts, which arise due to unique plant adaptations, marginal growing conditions, slow net primary production rates, and highly variable rainfall. We consider model uncertainty from both structural and parameter errors and present a mechanistic model for the shrub Larrea tridentata (creosote bush) under conditions found in the Mojave National Preserve in southeastern California (USA). Desert-specific plant and soil features are incorporated into the CLM-CN model by Oleson et al. (2010). We then develop a data assimilation framework using the ensemble Kalman filter (EnKF) to estimate model parameters based on soil moisture and leaf-area index observations. A new implementation procedure, the "multisite loop EnKF," tackles parameter estimation difficulties found to affect desert ecohydrological applications. Specifically, the procedure iterates through data from various observation sites to alleviate adverse filter impacts from non-Gaussianity in small desert vegetation state values. It also readjusts inconsistent parameters and states through a model spin-up step that accounts for longer dynamical time scales due to infrequent rainfall in deserts. Observation error variance inflation may also be needed to help prevent divergence of estimates from true values. Synthetic test results highlight the importance of adequate observations for reducing model uncertainty, which can be achieved through data quality or quantity.

  2. A mechanistic modeling and data assimilation framework for Mojave Desert ecohydrology

    Science.gov (United States)

    Ng, Gene-Hua Crystal.; Bedford, David; Miller, David

    2014-01-01

    This study demonstrates and addresses challenges in coupled ecohydrological modeling in deserts, which arise due to unique plant adaptations, marginal growing conditions, slow net primary production rates, and highly variable rainfall. We consider model uncertainty from both structural and parameter errors and present a mechanistic model for the shrub Larrea tridentata (creosote bush) under conditions found in the Mojave National Preserve in southeastern California (USA). Desert-specific plant and soil features are incorporated into the CLM-CN model by Oleson et al. (2010). We then develop a data assimilation framework using the ensemble Kalman filter (EnKF) to estimate model parameters based on soil moisture and leaf-area index observations. A new implementation procedure, the “multisite loop EnKF,” tackles parameter estimation difficulties found to affect desert ecohydrological applications. Specifically, the procedure iterates through data from various observation sites to alleviate adverse filter impacts from non-Gaussianity in small desert vegetation state values. It also readjusts inconsistent parameters and states through a model spin-up step that accounts for longer dynamical time scales due to infrequent rainfall in deserts. Observation error variance inflation may also be needed to help prevent divergence of estimates from true values. Synthetic test results highlight the importance of adequate observations for reducing model uncertainty, which can be achieved through data quality or quantity.

  3. ON PHYTOCOENOTICAL MAPPING OF CASPIAN DESERT REGION

    Directory of Open Access Journals (Sweden)

    I. SAFRONOVA

    2004-05-01

    Full Text Available The phytoecological map (l :2.500.000 for Desert Region, including the Caspian Lowland and the Mangyshlak. has been compiled. It gives an idea of latitudinal differentiation cf vegetation. Edaphic variants and lithological composition in low mountains. The legend has been constructed according to zonal-typological principle e using an ecological-phytocoenotic classification. Heterogeneity of vegetation is reflected by means of territoria1 units (complex, series, combination and additional marks above the vegetation background. In the northern subzone vegetation is fairly monotonous and characterized by prevalence of wormwood communities (Artemisia of subgenus Seriphidium, joined in three formations: Artemisia lerchiana, A. arenaria. A. pauciflora. Small areas are occupied by shrub deserts of Calligollum aphyllum and Tamarix ramosissima. To southward of 47° N in the middle subzone on the Caspian Lowland the communities of halophyte perennial saltworts essential1y dominate, and to less extent-wormwood communities of hemipsammophytic Artemisia terrae-albae and psammophytic Artemisia arenaria and A. lerchiana. Deserts of Mangyshlak are much diverse. Dwarf semishrubs are presented by species of perennial saltworts (Anabasis salsa, Nanophyton erinaceum,Arthrophytum lehnwnianum, Salsola orientaUs and wonnwood (Artemisia terrae-albae, A. gurganica. A. santolina. To southward of 43° N in the southern subzone dwarf semishrub Salsola gemmascens and Artemisia kemrudica corrnnunities prevail.

  4. ON PHYTOCOENOTICAL MAPPING OF CASPIAN DESERT REGION

    Directory of Open Access Journals (Sweden)

    I. SAFRONOVA

    2004-01-01

    Full Text Available The phytoecological map (l :2.500.000 for Desert Region, including the Caspian Lowland and the Mangyshlak. has been compiled. It gives an idea of latitudinal differentiation cf vegetation. Edaphic variants and lithological composition in low mountains. The legend has been constructed according to zonal-typological principle e using an ecological-phytocoenotic classification. Heterogeneity of vegetation is reflected by means of territoria1 units (complex, series, combination and additional marks above the vegetation background. In the northern subzone vegetation is fairly monotonous and characterized by prevalence of wormwood communities (Artemisia of subgenus Seriphidium, joined in three formations: Artemisia lerchiana, A. arenaria. A. pauciflora. Small areas are occupied by shrub deserts of Calligollum aphyllum and Tamarix ramosissima. To southward of 47° N in the middle subzone on the Caspian Lowland the communities of halophyte perennial saltworts essential1y dominate, and to less extent-wormwood communities of hemipsammophytic Artemisia terrae-albae and psammophytic Artemisia arenaria and A. lerchiana. Deserts of Mangyshlak are much diverse. Dwarf semishrubs are presented by species of perennial saltworts (Anabasis salsa, Nanophyton erinaceum,Arthrophytum lehnwnianum, Salsola orientaUs and wonnwood (Artemisia terrae-albae, A. gurganica. A. santolina. To southward of 43° N in the southern subzone dwarf semishrub Salsola gemmascens and Artemisia kemrudica corrnnunities prevail.

  5. The Palm Desert renewable [hydrogen] transportation system

    Energy Technology Data Exchange (ETDEWEB)

    Chamberlin, C.E.; Lehman, P. [Humboldt State Univ., Arcata, CA (United States). Schatz Energy Research Center

    1998-08-01

    This paper describes the Schatz Energy Research Center (SERC) progress on the Palm Desert Renewable Hydrogen Transportation System Project for the period June 1997 through May 1998. The project began in March 1996. The goal of the Palm Desert Project is to develop a clean and sustainable transportation system for a community. The project demonstrates the practical utility of hydrogen as a transportation fuel and the proton exchange membrane (PEM) fuel cell as a vehicle power system. The project includes designing and building 4 fuel cell powered vehicles, a solar hydrogen generating and refueling station, and a fuel cell vehicle diagnostic center. Over this last year, SERC has built a fuel cell powered neighborhood electric vehicle and delivered it to the City of Palm Desert. The design of the hydrogen refueling station is near completion and it is anticipated that construction will be complete in the fall of 1998. The vehicles are currently being refueled at a temporary refueling station. The diagnostic center is being designed and maintenance procedures as well as computer diagnostic programs for the fuel cell vehicles are being developed. City employees are driving the vehicles daily and monitoring data are being collected. The drivers are pleased with the performance of the vehicles.

  6. Rocks, climate and the survival of human societies in hyper-arid and arid environments - Are the human civilization in deserts at a permanent risk of collapse?

    Science.gov (United States)

    Yoav, Avni; Noa, Avriel-Avni

    2017-04-01

    The great challenges of living in the arid and hyper arid regions worldwide are the shortage of water, limited resources and the permanent uncertainty of the desert climate. These challenges are known as the main weaknesses of desert societies that are prone, according to the existing paradigm, to a permanent risk of collapse. However, in the Middle East deserts, human societies are known since prehistoric times and during the entire hyper-dry Holocene. This hints that the simple paradigm of desert societies' high vulnerability to harsh desert environments needs to be better examined. In this context we examine three case studies: 1. The Southern Sinai region in Egypt: In this region, the annual precipitation fluctuates between 20-50 mm/y. However, in this highly mountainous area, desert agriculture plots including orchards were constructed, located mainly around the byzantine monastery of Santa Katerina. During the last 1500 years, much of the water supply needed for humans and agriculture was generated from runoff developed on exposed granite rocks. 2. The southern Jordan region south of Petra: Much of this wide area connecting the deserts of the Arabian Peninsula and southern Jordan receive only 20-30 mm/y. However, the main caravan route established by the Arabian tribes during the first millennia BC managed to cross this land, supplying the water needs of many camels. Most of this water was stored in large cisterns dug into the sandstone rock formations exposed along the route, especially within the Disi Formation. 3. The Negev Highlands of southern Israel: This region is divided between the hyper arid region to the south, receiving 70-80 mm/y, and the arid region to the north receiving 90-130 mm/y. During the last two millennia, the hyper arid area was used for camel grazing and goats herds, while the northern sector was used for the construction of agriculture plots, agriculture farms and even desert towns. All these activities were sustained by runoff

  7. Use of space photographs in deciphering the origin and evolution of the desert

    International Nuclear Information System (INIS)

    El-Baz, F.

    1989-01-01

    Space photographs provide a very useful tool to study deserts and semiarid land because of their coverage and the amount of data they portray about vegetation-free terrain. This is a welcome contribution because we do not understand the desert as we do other types of terrain. Results of wind action, erosion and deposition are clearly portrayed in images obtained from spacecraft. They are indications of the state of the environment and should be studied well in all cases where economic development projects are instituted in deserts and semiarid lands. Furthermore, the history of evolution of the arid landscape in space and time must be considered in order to be able to use more of the desert for the benefit of mankind. (author). 33 refs, 14 figs

  8. Loess deposits since early Pleistocene in northeast China and implications for desert evolution in east China

    Science.gov (United States)

    Sun, Miao; Zhang, Xujiao; Tian, Mingzhong; Liu, Ru; He, Zexin; Qi, Lin; Qiao, Yansong

    2018-04-01

    Loess deposits and deserts are regarded as coupled geological systems and loess deposits on the periphery of deserts can often be used to reconstruct desert evolution. Previous studies of desert evolution in Asia are mainly concentrated in northwest China and the China Loess Plateau, and little is known about long-term desert evolution in east China. In this study, we selected the Sishijiazi loess section in the Chifeng area in northeast China to study the long-term evolution of the desert in east China. A high-resolution magnetostratigraphy combined with optically stimulated luminescence dating indicated that the age of the section base is approximately 1.02 Ma. The Brunhes-Matuyama boundary is at the depth of 39.8 m in loess unit L8, and the upper boundary of the Jaramillo Subchron is at the depth of 60.8 m in paleosol S10. The results of grain-size analysis indicate a coarsening grain-size trend in the past 1.0 Ma. In addition, based on grain-size variations, the desert evolution in east China since ∼1.0 Ma can be divided into three stages: stability from 1.0 to 0.8 Ma, desert recession from 0.8 to 0.5 Ma, and gradual expansion since 0.5 Ma. Our results further indicate that the evolution of desert in east China was mainly controlled by changes in global ice volume, and that the uplift of the Tibetan Plateau may have had an additional effect.

  9. Temporal 222Rn distributions to reveal groundwater discharge into desert lakes: Implication of water balance in the Badain Jaran Desert, China

    Science.gov (United States)

    Luo, Xin; Jiao, Jiu Jimmy; Wang, Xu-sheng; Liu, Kun

    2016-03-01

    How lake systems are maintained and water is balanced in the lake areas in the Badain Jaran Desert (BJD), northeast of China have been debated for about a decade. In this study, continuous 222Rn measurement is used to quantify groundwater discharge into two representative fresh and brine water lakes in the desert using a steady-state mass-balance model. Two empirical equations are used to calculate atmospheric evasion loss crossing the water-air interface of the lakes. Groundwater discharge rates yielded from the radon mass balance model based on the two empirical equations are well correlated and of almost the same values, confirming the validity of the model. The fresh water and brine lakes have a daily averaged groundwater discharge rate of 7.6 ± 1.7 mm d-1 and 6.4 ± 1.8 mm d-1, respectively. The temporal fluctuations of groundwater discharge show similar patterns to those of the lake water level, suggesting that the lakes are recharged from nearby groundwater. Assuming that all the lakes have the same discharge rate as the two studied lakes, total groundwater discharge into all the lakes in the desert is estimated to be 1.59 × 105 m3 d-1. A conceptual model of water balance within a desert lake catchment is proposed to characterize water behaviors within the catchment. This study sheds lights on the water balance in the BJD and is of significance in sustainable regional water resource utilization in such an ecologically fragile area.

  10. Great Excavations: Tales of Early Southwestern Archaeology, 1888-1939, School of American Research Press, 1995

    Directory of Open Access Journals (Sweden)

    Stephen E. Nash

    1997-05-01

    Full Text Available Great Excavations: Tales of Early Southwestern Archaeology, 1 888-1939, is an "intentionally selective" account of eight major archaeological expeditions to the Southwest in the late 19th and early 20th centuries. It succeeds in achieving the goals set forth in the prologue. The reader is taken on an "armchair tour"  of early Southwestern excavations in the hope that the resulting "basic understanding of what the early archae­ologists did" will stimulate a desire to "learn more about the intriguing prehistory of the Southwest" (pp. xiii. As a student of the history of North American archaeology, I would be amiss to speak for Elion's "layperson" audience, but my suspicion is that her presentation will indeed stimulate those readers. As an archaeologist, I thoroughly enjoyed this book, and it may well be that Elliott's journalistic approach makes this book more enjoyable because she is able to remain above the level of detail that often burden archaeolo­gists' accounts of these expeditions. I must temper this statement by noting that Elliott's journalistic hyper­ bole and tendency to oversimplify complex research and analysis are at times discomforting.

  11. Lithium abundance patterns of late-F stars: an in-depth analysis of the lithium desert

    Science.gov (United States)

    Aguilera-Gómez, Claudia; Ramírez, Iván; Chanamé, Julio

    2018-06-01

    Aims: We address the existence and origin of the lithium (Li) desert, a region in the Li-Teff plane sparsely populated by stars. Here we analyze some of the explanations that have been suggested for this region, including mixing in the late main sequence, a Li dip origin for stars with low Li abundances in the region, and a possible relation with the presence of planets. Methods: To study the Li desert, we measured the atmospheric parameters and Li abundance of 227 late-F dwarfs and subgiants, chosen to be in the Teff range of the desert and without previous Li abundance measurements. Subsequently, we complemented those with literature data to obtain a homogeneous catalog of 2318 stars, for which we compute masses and ages. We characterize stars surrounding the region of the Li desert. Results: We conclude that stars with low Li abundances below the desert are more massive and more evolved than stars above the desert. Given the unexpected presence of low Li abundance stars in this effective temperature range, we concentrate on finding their origin. We conclude that these stars with low Li abundance do not evolve from stars above the desert: at a given mass, stars with low Li (i.e., below the desert) are more metal-poor. Conclusions: Instead, we suggest that stars below the Li desert are consistent with having evolved from the Li dip, discarding the need to invoke additional mixing to explain this feature. Thus, stars below the Li desert are not peculiar and are only distinguished from other subgiants evolved from the Li dip in that their combination of atmospheric parameters locates them in a range of effective temperatures where otherwise only high Li abundance stars would be found (i.e., stars above the desert). Full Tables 1 and 3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A55This paper includes observations collected at The McDonald Observatory and

  12. Atmospheric Surface Layer Characterization: Preliminary Desert Lapse Rate Study 22-25 August 2000

    National Research Council Canada - National Science Library

    Elliott, Doyle

    2003-01-01

    Results of the August 2000 Desert Lapse Rate (DLR) Experiment are presented. The DLR Experiment was performed to document the night-to-day transition effects on the desert Atmospheric Surface Layer (ASL...

  13. Soil stabilization by a prokaryotic desert crust - Implications for Precambrian land biota

    Science.gov (United States)

    Campbell, S. E.

    1979-01-01

    The ecology of the cyanophyte-dominated stromatolitic mat forming the ground cover over desert areas of Utah and Colorado is investigated and implications for the formation of mature Precambrian soils are discussed. The activation of the growth of the two species of filamentous cyanophyte identified and the mobility of their multiple trichromes upon wetting are observed, accompanied by the production and deposition of a sheath capable of accreting and stabilizing sand and clay particles. The formation of calcium carbonate precipitates upon the repeated wetting and drying of desert crust is noted, and it is suggested that the desert crust community may appear in fossil calcrete deposits as lithified microscopic tubes and cellular remains of algal trichromes. The invasion of dry land by both marine and freshwater algae on the model of the desert crust is proposed to be responsible for the accumulation, stabilization and biogenic modification of mature Precambrian soils.

  14. Application of the North American Multi-Model Ensemble to seasonal water supply forecasting in the Great Lakes basin through the use of the Great Lakes Seasonal Climate Forecast Tool

    Science.gov (United States)

    Gronewold, A.; Apps, D.; Fry, L. M.; Bolinger, R.

    2017-12-01

    The U.S. Army Corps of Engineers (USACE) contribution to the internationally coordinated 6-month forecast of Great Lakes water levels relies on several water supply models, including a regression model relating a coming month's water supply to past water supplies, previous months' precipitation and temperature, and forecasted precipitation and temperature. Probabilistic forecasts of precipitation and temperature depicted in the Climate Prediction Center's seasonal outlook maps are considered to be standard for use in operational forecasting for seasonal time horizons, and have provided the basis for computing a coming month's precipitation and temperature for use in the USACE water supply regression models. The CPC outlook maps are a useful forecast product offering insight into interpretation of climate models through the prognostic discussion and graphical forecasts. However, recent evolution of USACE forecast procedures to accommodate automated data transfer and manipulation offers a new opportunity for direct incorporation of ensemble climate forecast data into probabilistic outlooks of water supply using existing models that have previously been implemented in a deterministic fashion. We will present results from a study investigating the potential for applying data from the North American Multi-Model Ensemble to operational water supply forecasts. The use of NMME forecasts is facilitated by a new, publicly available, Great Lakes Seasonal Climate Forecast Tool that provides operational forecasts of monthly average temperatures and monthly total precipitation summarized for each lake basin.

  15. Epifluorescent direct counts of bacteria and viruses from topsoil of various desert dust storm regions

    Science.gov (United States)

    Gonzalez-Martin, Cristina; Teigell-Perez, Nuria; Lyles, Mark; Valladares, Basilio; Griffin, Dale W.

    2013-01-01

    Topsoil from arid regions is the main source of dust clouds that move through the earth's atmosphere, and microbial communities within these soils can survive long-range dispersion. Microbial abundance and chemical composition were analyzed in topsoil from various desert regions. Statistical analyses showed that microbial direct counts were strongly positively correlated with calcium concentrations and negatively correlated with silicon concentrations. While variance between deserts was expected, it was interesting to note differences between sample sites within a given desert region, illustrating the 'patchy' nature of microbial communities in desert environments.

  16. Bacterial Rhizosphere Biodiversity from Several Pioneer Desert Sand Plants Near Jizan, Saudi Arabia

    KAUST Repository

    Osman, Jorge R.; Zelicourt, Axel de; Bisseling, Ton; Geurts, Rene; Hirt, Heribert; DuBow, Michael S.

    2016-01-01

    Life in arid regions and, in particular, hot deserts is often limited due to their harsh environmental conditions, such as large temperature fluctuations and low amounts of water. These extreme environments can influence the microbial community present on the surface sands and any rhizosphere members surrounding desert plant roots. The Jizan desert area, located in Saudi Arabia, supports particular vegetation that grows in the large sandy flat terrain. We examined five different samples, four from the rhizosphere of pioneer plants plus a surface sand sample, and used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples. The results showed a total of 3,530 OTUs in the five samples, calculated using ≥ 97% sequence similarity levels. The Chao1 estimation of the bacterial diversity fluctuated from 637 to 2,026 OTUs for a given sample. The most abundant members found in the samples belong to the Bacteroidetes, Firmicutes and Proteobacteria phyla. This work shows that the Jizan desert area of Saudi Arabia can contain a diverse bacterial community on the sand and surrounding the roots of pioneer desert plants. It also shows that desert sand microbiomes can vary depending on conditions, with broad implications for sandstone monument bacterial communities

  17. Bacterial Rhizosphere Biodiversity from Several Pioneer Desert Sand Plants Near Jizan, Saudi Arabia

    KAUST Repository

    Osman, Jorge R.

    2016-04-08

    Life in arid regions and, in particular, hot deserts is often limited due to their harsh environmental conditions, such as large temperature fluctuations and low amounts of water. These extreme environments can influence the microbial community present on the surface sands and any rhizosphere members surrounding desert plant roots. The Jizan desert area, located in Saudi Arabia, supports particular vegetation that grows in the large sandy flat terrain. We examined five different samples, four from the rhizosphere of pioneer plants plus a surface sand sample, and used pyrosequencing of PCR-amplified V1-V3 regions of 16S rDNA genes from total extracted DNA to reveal and compare the bacterial population diversity of the samples. The results showed a total of 3,530 OTUs in the five samples, calculated using ≥ 97% sequence similarity levels. The Chao1 estimation of the bacterial diversity fluctuated from 637 to 2,026 OTUs for a given sample. The most abundant members found in the samples belong to the Bacteroidetes, Firmicutes and Proteobacteria phyla. This work shows that the Jizan desert area of Saudi Arabia can contain a diverse bacterial community on the sand and surrounding the roots of pioneer desert plants. It also shows that desert sand microbiomes can vary depending on conditions, with broad implications for sandstone monument bacterial communities

  18. 77 FR 65133 - Revisions to the California State Implementation Plan, Mojave Desert Air Quality Management District

    Science.gov (United States)

    2012-10-25

    ... the California State Implementation Plan, Mojave Desert Air Quality Management District AGENCY... limited disapproval of revisions to the Mojave Desert Air Quality Management District (MDAQMD) portion of.... * * * * * (c) * * * (379) * * * (i) * * * (E) Mojave Desert Air Quality Management District. (1) Rule 1159...

  19. Scytonemin and Photosynthetic Pigment Proxies for Late Pleistocene/Holocene Environmental Change in the Eastern Great Basin

    Science.gov (United States)

    Fulton, J. M.; Van Mooy, B. A. S.

    2015-12-01

    Sedimentary pigments are biomarkers of photosynthetic organisms, most commonly derived from aquatic bacteria and algae but also with potential terrigenous sources. We detected a diverse pigment assemblage with variable down-core distributions in Great Salt Lake (GSL) sediments deposited since ca. 280 ka (GLAD1-GSL00, core 4). The most abundant pigments included derivatives of chlorophyll a, most likely from algae or cyanobacteria, bacteriochlorophyll c from green sulfur bacteria, okenone from purple sulfur bacteria, and scytonemin from UV-exposed cyanobacteria. Scytonemin is a biomarker for colonial cyanobacteria exposed to UV-radiation. In GSL it has potential sources from bioherms on the shoreline or microbiotic soil crusts from the adjacent Great Basin Desert. Scytonemin concentration was highest in the Upper Salt and Sapropel (USS) unit, deposited between 11.5-10 ka in shallow water (ca. 10 m), following deep pluvial Lake Bonneville (30-18 cal ka), the Provo lake level (ca. 18-15 cal ka), and the Gilbert transgression (11.6 cal ka). Scytonemin concentration was very low in sediments deposited during the deep lake phases, even though bioherms were prominent shoreline features. The USS was deposited under hypersaline waters and contained remarkably low concentrations of photosynthetic pigment derivatives that would be expected in organic-matter-rich sediments deposited under productive surface waters or anoxic bottom waters. Stable carbon and nitrogen isotopic data point toward a desert soil crust source for scytonemin in the USS, similar to what we previously observed in the Holocene Black Sea sapropel. We propose that increased aridity supported the widespread occurrence and erosion of microbiotic soil crusts during deposition of the USS. This is consistent with interpretations of Great Salt Lake hydrology, pointing toward a broader regional aridity event. Holocene sediments above the USS also contain scytonemin at relatively high concentration, consistent with

  20. Food deserts in Winnipeg, Canada: a novel method for measuring a complex and contested construct

    Directory of Open Access Journals (Sweden)

    Joyce Slater

    2017-10-01

    Full Text Available Introduction: "Food deserts" have emerged over the past 20 years as spaces of concern for communities, public health authorities and researchers because of their potential negative impact on dietary quality and subsequent health outcomes. Food deserts are residential geographic spaces, typically in urban settings, where low-income residents have limited or no access to retail food establishments with sufficient variety at affordable cost. Research on food deserts presents methodological challenges including retail food store identification and classification, identification of low-income populations, and transportation and proximity metrics. Furthermore, the complex methods often used in food desert research can be difficult to reproduce and communicate to key stakeholders. To address these challenges, this study sought to demonstrate the feasibility of implementing a simple and reproducible method of identifying food deserts using data easily available in the Canadian context. Methods: This study was conducted in Winnipeg, Canada in 2014. Food retail establishments were identified from Yellow Pages and verified by public health dietitians. We calculated two scenarios of food deserts based on location of the lowest-income quintile population: (a living ≥ 500 m from a national chain grocery store, or (b living ≥ 500 m from a national chain grocery store or a full-service grocery store. Results: The number of low-income residents living in a food desert ranged from 64 574 to 104 335, depending on the scenario used. Conclusion: This study shows that food deserts affect a significant proportion of the Winnipeg population, and while concentrated in the urban core, exist in suburban neighbourhoods also. The methods utilized represent an accessible and transparent, reproducible process for identifying food deserts. These methods can be used for costeffective, periodic surveillance and meaningful engagement with communities, retailers and policy

  1. Advances in Hydrogeochemical Indicators for the Discovery of New Geothermal Resources in the Great Basin, USA

    Energy Technology Data Exchange (ETDEWEB)

    Simmons, Stuart F. [Colorado School of Mines, Golden, CO (United States). Geology and Geological Engineering; Spycher, Nicolas [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Sonnenthal, Eric [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division; Dobson, Patrick [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Earth Sciences Division

    2013-05-20

    This report summarizes the results of Phase I work for a go/no go decision on Phase II funding. In the first objective, we assessed the extent to which fluid-mineral equilibria controlled deep water compositions in geothermal systems across the Great Basin. Six systems were evaluated: Beowawe; Desert Peak; Dixie Valley; Mammoth; Raft River; Roosevelt. These represent a geographic spread of geothermal resources, in different geological settings and with a wide range of fluid compositions. The results were used for calibration/reformulation of chemical geothermometers that reflect the reservoir temperatures in producing reservoirs. In the second objective, we developed a reactive -transport model of the Desert Peak hydrothermal system to evaluate the processes that affect reservoir fluid geochemistry and its effect on solute geothermometry. This included testing geothermometry on “reacted” thermal water originating from different lithologies and from near-surface locations where the temperature is known from the simulation. The integrated multi-component geothermometer (GeoT, relying on computed mineral saturation indices) was tested against the model results and also on the systems studied in the first objective.

  2. Metabolic rate, evaporative water loss and thermoregulatory state in four species of bats in the Negev desert.

    Science.gov (United States)

    Muñoz-Garcia, Agustí; Larraín, Paloma; Ben-Hamo, Miriam; Cruz-Neto, Ariovaldo; Williams, Joseph B; Pinshow, Berry; Korine, Carmi

    2016-01-01

    Life in deserts is challenging for bats because of their relatively high energy and water requirements; nevertheless bats thrive in desert environments. We postulated that bats from desert environments have lower metabolic rates (MR) and total evaporative water loss (TEWL) than their mesic counterparts. To test this idea, we measured MR and TEWL of four species of bats, which inhabit the Negev desert in Israel, one species mainly restricted to hyper-arid deserts (Otonycteris hemprichii), two species from semi-desert areas (Eptesicus bottae and Plecotus christii), and one widespread species (Pipistrellus kuhlii). We also measured separately, in the same individuals, the two components of TEWL, respiratory water loss (RWL) and cutaneous evaporative water loss (CEWL), using a mask. In all the species, MR and TEWL were significantly reduced during torpor, the latter being a consequence of reductions in both RWL and CEWL. Then, we evaluated whether MR and TEWL in bats differ according to their geographic distributions, and whether those rates change with Ta and the use of torpor. We did not find significant differences in MR among species, but we found that TEWL was lowest in the species restricted to desert habitats, intermediate in the semi-desert dwelling species, and highest in the widespread species, perhaps a consequence of adaptation to life in deserts. Our results were supported by a subsequent analysis of data collected from the literature on rates of TEWL for 35 bat species from desert and mesic habitats. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. 76 FR 29153 - Revisions to the California State Implementation Plan, Mojave Desert Air Quality Management District

    Science.gov (United States)

    2011-05-20

    ... the California State Implementation Plan, Mojave Desert Air Quality Management District AGENCY... approve revisions to the Mojave Desert Air Quality Management District (MDAQMD) portion of the California... approving with the dates that they were adopted by the Mojave Desert Air Quality Management District (MDAQMD...

  4. Medicinal flora of the Cholistan desert: a review

    International Nuclear Information System (INIS)

    Hmeed, M.; Ashraf, M.; Nawaz, T.; Naz, N.; Ahmad, M.S.A.; Al-Quriany, F.; Younis, A.

    2011-01-01

    The Cholistan desert can be divided into two distinct regions on the basis of topography, soil type and texture, and vegetation structure: the northern Lesser Cholistan and southern Greater Cholistan. The desert is characterized by large saline compacted areas with alluvial clay, sandy ridges and dunes, and semi-stabilized to frequently shifting dunes. The climate is subtropical, harsh, hot and arid, and influenced by seasonal monsoons. Vegetation cover on the sand dunes is comprised by a few tussock-forming grasses including Cenchrus ciliaris, Panicum turgidum and Lasiurus scindicus, along with perennial shrubs Calligonum polygonoides, Leptadenia pyrotechnica and Aerva javanica. Interdunal flats are dominated by grasses, mainly Cymbopogon jwarancusa, Sporobolus ioclados, Panicum antidotale, and Ochthochloa compressa, and tall shrubs Calligonum polygonoides and Capparis decidua. Vegetation of saline patches is specific, dominated by halophytes mainly belonging to family Chenopodiaceae (Amaranthaceae). Many plants of the Cholistan desert, including Neurada procumbens, Aerva javanica, Capparis decidua, Cleome brachycarpa, Dipterygium glaucum, Gisekia pharnacioides, Suaeda fruticosa, Achyranthes aspera, Aerva javanica, Alhagi maurorum, Calotropis procera, Capparis decidua, Zaleya pentandra, Mollugo cerviana, Ziziphus mauritiana, Boerhavia procumbens, Cressa cretica and Crotalaria burhia, are frequently used by the local inhabitants to cure chronic and acute diseases. A variety of medicinally important chemical compounds have been extracted and identified from the plants of the Cholistan desert, including terpenes and triterpenoids, sterols and steroids, phenolics, flavonoids, gums and resins, quinones, anthocyanidines, saponins, antioxidants and fatty acids. Habitat degradation, intensive agricultural practices and over exploitation of resources pose a serious threat to the diversity of ethno botanically important plant species. Allopathic medicines are generally

  5. War or Peace? How the Subjective Perception of Great Power Interdependence Shapes Preemptive Defensive Aggression.

    Science.gov (United States)

    Jing, Yiming; Gries, Peter H; Li, Yang; Stivers, Adam W; Mifune, Nobuhiro; Kuhlman, D M; Bai, Liying

    2017-01-01

    Why do great powers with benign intentions end up fighting each other in wars they do not seek? We utilize an incentivized, two-person "Preemptive Strike Game" (PSG) to explore how the subjective perception of great power interdependence shapes defensive aggression against persons from rival great powers. In Study 1, college students from the United States ( N = 115), China ( N = 106), and Japan ( N = 99) made PSG decisions facing each other. This natural experiment revealed that Chinese and Japanese participants (a) made more preemptive attacks against each other and Americans than against their compatriots, and that (b) greater preexisting perceptions of bilateral competition increased intergroup attack rates. In Study 2, adult Americans ( N = 127) watched real CNN expert interviews portraying United States-China economic interdependence as more positive or negative. This randomized experiment revealed that the more positive portrayal reduced preemptive American strikes against Chinese (but not Japanese), while the more negative portrayal amplified American anger about China's rise, increasing preemptive attacks against Chinese. We also found, however, that preemptive strikes were primarily defensive and not offensive. Interventions to reduce defensive aggression and promote great power peace are discussed.

  6. War or Peace? How the Subjective Perception of Great Power Interdependence Shapes Preemptive Defensive Aggression

    Directory of Open Access Journals (Sweden)

    Yiming Jing

    2017-06-01

    Full Text Available Why do great powers with benign intentions end up fighting each other in wars they do not seek? We utilize an incentivized, two-person “Preemptive Strike Game” (PSG to explore how the subjective perception of great power interdependence shapes defensive aggression against persons from rival great powers. In Study 1, college students from the United States (N = 115, China (N = 106, and Japan (N = 99 made PSG decisions facing each other. This natural experiment revealed that Chinese and Japanese participants (a made more preemptive attacks against each other and Americans than against their compatriots, and that (b greater preexisting perceptions of bilateral competition increased intergroup attack rates. In Study 2, adult Americans (N = 127 watched real CNN expert interviews portraying United States–China economic interdependence as more positive or negative. This randomized experiment revealed that the more positive portrayal reduced preemptive American strikes against Chinese (but not Japanese, while the more negative portrayal amplified American anger about China’s rise, increasing preemptive attacks against Chinese. We also found, however, that preemptive strikes were primarily defensive and not offensive. Interventions to reduce defensive aggression and promote great power peace are discussed.

  7. Who Needs Religion When You Have The Desert?

    DEFF Research Database (Denmark)

    Sørensen, Bent

    In my paper I propose to read so-called ‘post-ironic’ texts by authors associated with the Blank Generation and Generation X (including Bret Easton Ellis and Douglas Coupland, as well as less well-known authors such as K.S. Haddock) and examine their use of the desert as a trope for identity...... testing and summation. Perhaps surprisingly, one finds in novels such as Ellis’ Less Than Zero (1984) and Coupland’s Generation X (1991) a reliance on desert locations to provide an alternative to the numerous non-places (in Marc Augé’s sense of the term) that otherwise make up the setting of these works....

  8. The Mojave Desert: A Martian Analog Site for Future Astrobiology Themed Missions

    Science.gov (United States)

    Salas, E.; Abbey, W.; Bhartia, R.; Beegle, L. W.

    2011-01-01

    Astrobiological interest in Mars is highlighted by evidence that Mars was once warm enough to have liquid water present on its surface long enough to create geologic formations that could only exist in the presense of extended fluvial periods. These periods existed at the same time life on Earth arose. If life began on Mars as well during this period, it is reasonable to assume it may have adapted to the subsurface as environments at the surface changed into the inhospitable state we find today. If the next series of Mars missions (Mars Science Laboratory, the ExoMars Trace Gas Orbiter proposed for launch in 2016, and potential near surface sample return) fail to discover either extinct or extant life on Mars, a subsurface mission would be necessary to attempt to "close the book" on the existence of martian life. Mars is much colder and drier than Earth, with a very low pressure CO2 environment and no obvious habitats. Terrestrial regions with limited precipitation, and hence reduced active biota, are some of the best martian low to mid latitude analogs to be found on Earth, be they the Antarctic dry valleys, the Atacama or Mojave Deserts. The Mojave Desert/Death Valley region is considered a Mars analog site by the Terrestrial Analogs Panel of the NSF-sponsored decadal survey; a field guide was even developed and a workshop was held on its applicability as a Mars analog. This region has received a great deal of attention due to its accessibility and the variety of landforms and processes observed relevant to martian studies.

  9. Recovery of compacted soils in Mojave Desert ghost towns.

    Science.gov (United States)

    Webb, R.H.; Steiger, J.W.; Wilshire, H.G.

    1986-01-01

    Residual compaction of soils was measured at seven sites in five Mojave Desert ghost towns. Soils in these Death Valley National Monument townsites were compacted by vehicles, animals, and human trampling, and the townsites had been completely abandoned and the buildings removed for 64 to 75 yr. Recovery times extrapolated using a linear recovery model ranged from 80 to 140 yr and averaged 100 yr. The recovery times were related to elevation, suggesting freeze-thaw loosening as an important factor in ameliorating soil compaction in the Mojave Desert. -from Authors

  10. Natural product diversity of actinobacteria in the Atacama Desert.

    Science.gov (United States)

    Rateb, Mostafa E; Ebel, Rainer; Jaspars, Marcel

    2018-02-14

    The Atacama Desert of northern Chile is considered one of the most arid and extreme environment on Earth. Its core region was described as featuring "Mars-like" soils that were at one point deemed too extreme for life to exist. However, recent investigations confirmed the presence of diverse culturable actinobacteria. In the current review, we discuss a total of 46 natural products isolated to date representing diverse chemical classes characterized from different actinobacteria isolated from various locations in the Atacama Desert. Their reported biological activities are also discussed.

  11. Water sources for cyanobacteria below desert rocks in the Negev Desert determined by conductivity

    Directory of Open Access Journals (Sweden)

    Christopher P. McKay

    2016-04-01

    Full Text Available We present year round meteorological and conductivity measurements of colonized hypolithic rocks in the Arava Valley, Negev Desert, Israel. The data indicate that while dew is common in the Negev it is not an important source of moisture for hypolithic organisms at this site. The dominance of cyanobacteria in the hypolithic community is consistent with predictions that cyanobacteria are confined to habitats supplied by rain. To monitor the presence of liquid water under the small Negev rocks we developed and tested a simple field conductivity system based on two wires placed about 0.5 cm apart. Based on 21 replicates recorded for one year in the Negev we conclude that in natural rains (0.25 mm to 6 mm the variability between sensor readings is between 20 and 60% decreasing with increasing rain amount. We conclude that the simple small electrical conductivity system described here can be used effectively to monitor liquid water levels in lithic habitats. However, the natural variability of these sensors indicates that several replicates should be deployed. The results and method presented have use in arid desert reclamation programs.

  12. Serologic and molecular evidence for testudinid herpesvirus 2 infection in wild Agassiz’s desert tortoise, Gopherus agassizii

    Science.gov (United States)

    Jacobson, Elliott R.; Berry, Kristin H.; Wellehan, James F. X.; Origgi, Francesco; Childress, April L.; Braun, Josephine; Schrenzel, Mark; Yee, Julie; Rideout, Bruce

    2012-01-01

    Following field observations of wild Agassiz’s desert tortoises (Gopherus agassizii) with oral lesions similar to those seen in captive tortoises with herpesvirus infection, we measured the prevalence of antibodies to Testudinid herpesvirus (TeHV) 3 in wild populations of desert tortoises in California. The survey revealed 30.9% antibody prevalence. In 2009 and 2010, two wild adult male desert tortoises, with gross lesions consistent with trauma and puncture wounds, respectively, were necropsied. Tortoise 1 was from the central Mojave Desert and tortoise 2 was from the northeastern Mojave Desert. We extracted DNA from the tongue of tortoise 1 and from the tongue and nasal mucosa of tortoise 2. Sequencing of polymerase chain reaction products of the herpesviral DNA-dependent DNA polymerase gene and the UL39 gene respectively showed 100% nucleotide identity with TeHV2, which was previously detected in an ill captive desert tortoise in California. Although several cases of herpesvirus infection have been described in captive desert tortoises, our findings represent the first conclusive molecular evidence of TeHV2 infection in wild desert tortoises. The serologic findings support cross-reactivity between TeHV2 and TeHV3. Further studies to determine the ecology, prevalence, and clinical significance of this virus in tortoise populations are needed.

  13. Giant desiccation fissures on the Black Rock and Smoke Creek Deserts, Nevada

    Science.gov (United States)

    Willden, R.; Mabey, D.R.

    1961-01-01

    Open fissures, from 100 to several hundred feet apart, that have produced polygonal patterns on the Black Rock Desert, Nevada, are believed to be giant desiccation cracks resulting from a secular trend toward aridity in the last few decades. Similar features on the Smoke Creek Desert probably have the same origin.

  14. [Analysis of spectral features based on water content of desert vegetation].

    Science.gov (United States)

    Zhao, Zhao; Li, Xia; Yin, Ye-biao; Tang, Jin; Zhou, Sheng-bin

    2010-09-01

    By using HR-768 field-portable spectroradiometer made by the Spectra Vista Corporation (SVC) of America, the hyper-spectral data of nine types of desert plants were measured, and the water content of corresponding vegetation was determined by roasting in lab. The continuum of measured hyperspectral data was removed by using ENVI, and the relationship between the water content of vegetation and the reflectance spectrum was analyzed by using correlation coefficient method. The result shows that the correlation between the bands from 978 to 1030 nm and water content of vegetation is weak while it is better for the bands from 1133 to 1266 nm. The bands from 1374 to 1534 nm are the characteristic bands because of the correlation between them and water content is the best. By using cluster analysis and according to the water content, the vegetation could be marked off into three grades: high (>70%), medium (50%-70%) and low (<50%). The research reveals the relationship between water content of desert vegetation and hyperspectral data, and provides basis for the analysis of area in desert and the monitoring of desert vegetation by using remote sensing data.

  15. Desert rose: building material of cupolas in the Souf in Algeria

    Science.gov (United States)

    Azil, C.; Djebri, B.; Rovero, L.

    2018-05-01

    In the Souf of Algeria, the roofs of all constructions are arranged like corbelled domes, built with local particular material to this region, which is the desert rose. These cupolas describe a unique landscape of historic centres. Such constructions include a widespread and precious heritage that deserves protection to save this urban landscape which constitutes an element of identity of heritage built upon the material as well as the immaterial of the local know-how. Unfortunately, these architectural elements have undergone alterations that devalue the urban landscape and destabilize the buildings. However, the structural system that provides stability and endurance to this day remains an open question. In this, paper, we describe the role of desert rose cupolas in the construction of a single urban landscape and we contribute to this knowledge. Then, we explain the role of the availability of the materials locals (desert rose and tafza) to appearance ad emergence of construction with cupolas typology. In addition, we describe these materials locals, and the method to them usage. In the end, we have traced the process of construction of these cupolas by corbelling which is mounted by successive courses of the desert rose and the plaster mortar.

  16. Reconstructing the origin of Helianthus deserticola: Survival and selection on the desert floor

    NARCIS (Netherlands)

    Gross, B.L.; Kane, D.L.; Lexer, C.; Ludwig, F.; Rosenthal, D.R.; Donovan, L.A.; Rieseberg, L.H.

    2004-01-01

    The diploid hybrid species Helianthus deserticola inhabits the desert floor, an extreme environment relative to its parental species Helianthus annuus and Helianthus petiolaris. Adaptation to the desert floor may have occurred via selection acting on transgressive, or extreme, traits in early

  17. Biological soil crusts as an integral component of desert environments

    Science.gov (United States)

    Belnap, Jayne; Weber, Bettina

    2013-01-01

    The biology and ecology of biological soil crusts, a soil surface community of mosses, lichens, cyanobacteria, green algae, fungi, and bacteria, have only recently been a topic of research. Most efforts began in the western U.S. (Cameron, Harper, Rushforth, and St. Clair), Australia (Rogers), and Israel (Friedmann, Evenari, and Lange) in the late 1960s and 1970s (e.g., Friedmann et al. 1967; Evenari 1985reviewed in Harper and Marble 1988). However, these groups worked independently of each other and, in fact, were often not aware of each other’s work. In addition, biological soil crust communities were seen as more a novelty than a critical component of dryland ecosystems. Since then, researchers have investigated many different aspects of these communities and have shown that although small to microscopic, biological soil crusts are critical in many ecological processes of deserts. They often cover most of desert soil surfaces and substantially mediate inputs and outputs from desert soils (Belnap et al. 2003). They can be a large source of biodiversity for deserts, as they can contain more species than the surrounding vascular plant community (Rosentreter 1986). These communities are important in reducing soil erosion and increasing soil fertility through the capture of dust and the fixation of atmospheric nitrogen and carbon into forms available to other life forms (Elbert et al. 2012). Because of their many effects on soil characteristics, such as external and internal morphological characteristics, aggregate stability, soil moisture, and permeability, they also affect seed germination and establishment and local hydrological cycles. Covering up to 70% of the surface area in many arid and semi-arid regions around the world (Belnap and Lange 2003), biological soil crusts are a key component within desert environments.

  18. Resource pulses in desert river habitats: productivity-biodiversity hotspots, or mirages?

    Science.gov (United States)

    Free, Carissa L; Baxter, Greg S; Dickman, Christopher R; Leung, Luke K P

    2013-01-01

    Resource pulses in the world's hot deserts are driven largely by rainfall and are highly variable in both time and space. However, run-on areas and drainage lines in arid regions receive more water more often than adjacent habitats, and frequently sustain relatively high levels of primary productivity. These landscape features therefore may support higher biotic diversity than other habitats, and potentially act as refuges for desert vertebrates and other biota during droughts. We used the ephemeral Field River in the Simpson Desert, central Australia, as a case study to quantify how resources and habitat characteristics vary spatially and temporally along the riparian corridor. Levels of moisture and nutrients were greater in the clay-dominated soils of the riverine corridor than in the surrounding sand dunes, as were cover values of trees, annual grasses, other annual plants and litter; these resources and habitat features were also greater near the main catchment area than in the distal reaches where the river channel runs out into extensive dune fields. These observations confirm that the riverine corridor is more productive than the surrounding desert, and support the idea that it may act as a refuge or as a channel for the ingress of peri-desert species. However, the work also demonstrates that species diversity of invertebrates and plants is not higher within the river corridor; rather, it is driven by rainfall and the accompanying increase in annual plants following a rain event. Further research is required to identify the biota that depend upon these resource pulses.

  19. Resource Pulses in Desert River Habitats: Productivity-Biodiversity Hotspots, or Mirages?

    Science.gov (United States)

    Free, Carissa L.; Baxter, Greg S.; Dickman, Christopher R.; Leung, Luke K. P.

    2013-01-01

    Resource pulses in the world's hot deserts are driven largely by rainfall and are highly variable in both time and space. However, run-on areas and drainage lines in arid regions receive more water more often than adjacent habitats, and frequently sustain relatively high levels of primary productivity. These landscape features therefore may support higher biotic diversity than other habitats, and potentially act as refuges for desert vertebrates and other biota during droughts. We used the ephemeral Field River in the Simpson Desert, central Australia, as a case study to quantify how resources and habitat characteristics vary spatially and temporally along the riparian corridor. Levels of moisture and nutrients were greater in the clay-dominated soils of the riverine corridor than in the surrounding sand dunes, as were cover values of trees, annual grasses, other annual plants and litter; these resources and habitat features were also greater near the main catchment area than in the distal reaches where the river channel runs out into extensive dune fields. These observations confirm that the riverine corridor is more productive than the surrounding desert, and support the idea that it may act as a refuge or as a channel for the ingress of peri-desert species. However, the work also demonstrates that species diversity of invertebrates and plants is not higher within the river corridor; rather, it is driven by rainfall and the accompanying increase in annual plants following a rain event. Further research is required to identify the biota that depend upon these resource pulses. PMID:24124446

  20. Microbial communities in a High Arctic polar desert landscape

    Directory of Open Access Journals (Sweden)

    Clare M McCann

    2016-03-01

    Full Text Available The High Arctic is dominated by polar desert habitats whose microbial communities are poorly understood. In this study, we used next generation sequencing to describe the α- and β-diversity of polar desert soils from the Kongsfjorden region of Svalbard. Ten phyla consistently dominated the soils and accounted for 95 % of all sequences, with Proteobacteria, Actinobacteria and Chloroflexi being the dominant lineages. In contrast to previous investigations of Arctic soils, Acidobacterial relative abundances were low as were the Archaea throughout the Kongsfjorden polar desert landscape. Lower Acidobacterial abundances were attributed to the circumneutral soil pH in this region which has resulted from the weathering of the underlying carbonate geology. In addition, we correlated previously measured geochemical variables to determine potential controls on the communities. Soil phosphorus, pH, nitrogen and calcium significantly correlated with β-diversity indicating a landscape scale lithological control of soil nutrients which in turn influenced community composition. In addition, soil phosphorus and pH significantly correlated with α- diversity, specifically the Shannon diversity and Chao 1 richness indices.

  1. Gardening guide for high-desert urban landscapes of Great Basin regions in Nevada and Utah

    Science.gov (United States)

    Heidi Kratsch; Rick Heflebower

    2013-01-01

    Some Great Basin urban areas in Utah and Nevada exhibit climatic conditions that make it difficult for all but the toughest landscape plants to thrive without providing supplemental water. These areas are found at elevations from 4,000 feet to 6,000 feet in USDA cold-hardiness zones 6 and 7. Soils are often poor and gravelly, containing less than 1 percent organic...

  2. 76 FR 28767 - Desert Southwest Customer Service Region-Rate Order No. WAPA-152

    Science.gov (United States)

    2011-05-18

    ... DEPARTMENT OF ENERGY Western Area Power Administration Desert Southwest Customer Service Region..., Desert Southwest Customer Service Region, Western Area Power Administration, P.O. Box 6457, Phoenix, AZ... Customer Service Region, Western Area Power Administration, P.O. Box 6457, Phoenix, AZ 85005-6457, (602...

  3. Urban particle size distributions during two contrasting dust events originating from Taklimakan and Gobi Deserts

    International Nuclear Information System (INIS)

    Zhao, Suping; Yu, Ye; Xia, Dunsheng; Yin, Daiying; He, Jianjun; Liu, Na; Li, Fang

    2015-01-01

    The dust origins of the two events were identified using HYSPLIT trajectory model and MODIS and CALIPSO satellite data to understand the particle size distribution during two contrasting dust events originated from Taklimakan and Gobi deserts. The supermicron particles significantly increased during the dust events. The dust event from Gobi desert affected significantly on the particles larger than 2.5 μm, while that from Taklimakan desert impacted obviously on the particles in 1.0–2.5 μm. It is found that the particle size distributions and their modal parameters such as VMD (volume median diameter) have significant difference for varying dust origins. The dust from Taklimakan desert was finer than that from Gobi desert also probably due to other influencing factors such as mixing between dust and urban emissions. Our findings illustrated the capacity of combining in situ, satellite data and trajectory model to characterize large-scale dust plumes with a variety of aerosol parameters. - Highlights: • Dust particle size distributions had large differences for varying origins. • Dust originating from Taklimakan Desert was finer than that from Gobi Desert. • Effect of dust on the supermicron particles was obvious. • PM_1_0 concentrations increased by a factor of 3.4–25.6 during the dust event. - Dust particle size distributions had large differences for varying origins, which may be also related to other factors such as mixing between dust and urban emissions.

  4. The Plant Genetic Engineering Laboratory For Desert Adaptation

    Science.gov (United States)

    Kemp, John D.; Phillips, Gregory C.

    1985-11-01

    The Plant Genetic Engineering Laboratory for Desert Adaptation (PGEL) is one of five Centers of Technical Excellence established as a part of the state of New Mexico's Rio Grande Research Corridor (RGRC). The scientific mission of PGEL is to bring innovative advances in plant biotechnology to bear on agricultural productivity in arid and semi-arid regions. Research activities focus on molecular and cellular genetics technology development in model systems, but also include stress physiology investigations and development of desert plant resources. PGEL interacts with the Los Alamos National Laboratory (LANL), a national laboratory participating in the RGRC. PGEL also has an economic development mission, which is being pursued through technology transfer activities to private companies and public agencies.

  5. Asian American Giving to US Higher Education

    Science.gov (United States)

    Tsunoda, Kozue

    2010-01-01

    Asian Americans have had significant impacts on and within mainstream US society, and their great efforts and gifts in the name of charitable causes are no exception. This study aims to examine perceptions within American university development offices about Asian American giving to US higher education. The article begins with a literature review…

  6. Spatial probability models of fire in the desert grasslands of the southwestern USA

    Science.gov (United States)

    Fire is an important driver of ecological processes in semiarid environments; however, the role of fire in desert grasslands of the Southwestern US is controversial and the regional fire distribution is largely unknown. We characterized the spatial distribution of fire in the desert grassland region...

  7. Site selection and directional models of deserts used for ERBE validation targets

    Science.gov (United States)

    Staylor, W. F.

    1986-01-01

    Broadband shortwave and longwave radiance measurements obtained from the Nimbus 7 Earth Radiation Budget scanner were used to develop reflectance and emittance models for the Sahara, Gibson, and Saudi Deserts. These deserts will serve as in-flight validation targets for the Earth Radiation Budget Experiment being flown on the Earth Radiation Budget Satellite and two National Oceanic and Atmospheric Administration polar satellites. The directional reflectance model derived for the deserts was a function of the sum and product of the cosines of the solar and viewing zenith angles, and thus reciprocity existed between these zenith angles. The emittance model was related by a power law of the cosine of the viewing zenith angle.

  8. Diversity and richness of benthic insects in three cold desert spring-streams

    Energy Technology Data Exchange (ETDEWEB)

    Gaines, W.L.; Cushing, C.E. [Pacific Northwest Lab., Richland, WA (United States)

    1993-05-01

    The authors examined species diversity and richness in three cold desert spring-streams, and showed that species diversity was similar and species richness was lower than in similar-size streams from other and or semi-arid regions. Species diversity in the spring-streams increased with increasing stream size and substratum diversity, but declined as distance increased from the nearest large source. However, this latter relationship is difficult to quantify because the nearest large source was the Columbia River, or one of its reservoirs, that has environmental conditions very different from those found in the study streams. It is more likely that the main source of colonizers for the spring-streams studied were other nearby small springs that could provide sources or stepping stone habitats for colonizers. Species diversity declined after winter spates, and the low species diversity and richness values appear to be greatly influenced by these events.

  9. Exploring the Limits to Photosynthetic Life in the Hyperarid Atacama (Chile) and Taklimakan (China) Deserts

    Science.gov (United States)

    Warren-Rhodes, K.; Ewing, S.; McKay, C. P.; Rhodes, K. L.

    2003-12-01

    Photosynthetic microbes inhabiting the cracks or fissures (chasmoendoliths) and undersides (hypoliths) of translucent stones function as the sole primary producers in the world's driest deserts. This poster reports on our studies of the distribution and survival of these microorganisms in the hyperarid core of the Atacama Desert--an extreme environment previously considered too dry to support photosynthetic life--and the Taklimakan Desert in China--one of the oldest and driest deserts on the Earth. In both deserts, we measured colonization rates and microclimate variables across natural precipitation gradients in order to investigate the role of moisture in the ecology and survival of hypolithic and chasmoendolithic microorganisms. Our results show 1000-fold variations in colonization rates--from 12% in the wettest portions of the Taklimakan Desert to 3000 y. At slightly wetter sites in the Atacama, Δ 14C of hypolith soils was progressively more enriched in proportion to increased MAP, with corresponding turnover times of >600 y (Δ 14C = -73 ‰ at sites with ˜5-10 mm MAP and ˜1 y Δ 14C = +12 ‰ ) as annual rainfall increased to ˜25 mm. At all sites, Δ 14C signatures of non-hypolith soils corresponded to turnover times that were longer by an order of magnitude, indicating significantly slower OC cycling by non-hypoliths. In the hyperarid core of the Atacama Desert, the prolonged lack of rainfall (decadal scales of a few millimeters) is responsible for possibly the lowest hypolithic and chasmoendolithic colonization rates observed in deserts on the Earth. Microclimate data for rock and soil surface moisture from rainfall, dew and frost suggest the particular form of moisture and its frequency may also explain observed differences in hypolithic versus chasmoendolithic colonization modes. These results hold theoretical and practical considerations for both terrestrial ecology and as analogs for possible life on Mars.

  10. Response of the desert shrub Krameria parvifolia after ten years of chronic gamma irradiation

    International Nuclear Information System (INIS)

    Vollmer, A.T.; Bamberg, S.A.

    1975-01-01

    A northern Mojave Desert shrub community was irradiated by a 137 Cs source for a ten-year period. Leaf and fruit production, cover, and percent live stem of Krameria parvifolia shrubs were found to respond significantly to a radiation gradient with exposure rates ranging from 0.1 to 10 R/day. Fruit and leaf production were greatly reduced at exposures over 6 R/day. Above 7 R/day 16% of the shrubs were dead compared to 1.2% in a non-irradiated area. Reduced cover, density and live stem values indicate a trend toward a lower status of Krameria in the community at cumulative exposures above 25 kR. Observations indicate that an equilibrium in response to irradiation has not yet occurred. Radiosensitivity of K. parvifolia is attributed in part to its phenology. (author)

  11. Response of the desert shrub Krameria parvifolia after ten years of chronic gamma irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Vollmer, A T; Bamberg, S A [California Univ., Los Angeles (USA). Lab. of Nuclear Medicine and Radiation Biology

    1975-12-01

    A northern Mojave Desert shrub community was irradiated by a /sup 137/Cs source for a ten-year period. Leaf and fruit production, cover, and percent live stem of Krameria parvifolia shrubs were found to respond significantly to a radiation gradient with exposure rates ranging from 0.1 to 10 R/day. Fruit and leaf production were greatly reduced at exposures over 6 R/day. Above 7 R/day 16% of the shrubs were dead compared to 1.2% in a non-irradiated area. Reduced cover, density and live stem values indicate a trend toward a lower status of Krameria in the community at cumulative exposures above 25 kR. Observations indicate that an equilibrium in response to irradiation has not yet occurred. Radiosensitivity of K. parvifolia is attributed in part to its phenology.

  12. A Systematic Review of Wild Burro Grazing Effects on Mojave Desert Vegetation, USA

    Science.gov (United States)

    Abella, Scott R.

    2008-06-01

    Wild burros ( Equus asinus), protected by the 1971 Wild Free-Roaming Horse and Burro Act on some federal lands but exotic animals many ecologists and resource mangers view as damaging to native ecosystems, represent one of the most contentious environmental management problems in American Southwest arid lands. This review synthesizes the scattered literature about burro effects on plant communities of the Mojave Desert, a center of burro management contentions. I classified 24 documents meeting selection criteria for this review into five categories of research: (i) diet analyses directly determining which plant species burros consume, (ii) utilization studies of individual species, (iii) control-impact comparisons, (iv) exclosure studies, and (v) forage analyses examining chemical characteristics of forage plants. Ten diet studies recorded 175 total species that burros consumed. However, these studies and two exclosure studies suggested that burros preferentially eat graminoid and forb groups over shrubs. One study in Death Valley National Park, for example, found that Achnatherum hymenoides (Indian ricegrass) was 11 times more abundant in burro diets than expected based on its availability. Utilization studies revealed that burros also exhibit preferences within the shrub group. Eighty-three percent of reviewed documents were produced in a 12-year period, from 1972 to 1983, with the most recent document produced in 1988. Because burros remain abundant on many federal lands and grazing may interact with other management concerns (e.g., desert wildfires fueled by exotic grasses), rejuvenating grazing research to better understand both past and present burro effects could help guide revegetation and grazing management scenarios.

  13. Supersymmetry without the Desert

    International Nuclear Information System (INIS)

    Nomura, Yasunori; Poland, David

    2006-01-01

    Naturalness of electroweak symmetry breaking in weak scale supersymmetric theories may suggest the absence of the conventional supersymmetric desert. We present a simple, realistic framework for supersymmetry in which (most of) the virtues of the supersymmetric desert are naturally reproduced without having a large energy interval above the weak scale. The successful supersymmetric prediction for the low-energy gauge couplings is reproduced due to a gauged R symmetry present in the effective theory at the weak scale. The observable sector superpotential naturally takes the form of the next-to-minimal supersymmetric standard model, but without being subject to the Landau pole constraints up to the conventional unification scale. Supersymmetry breaking masses are generated by the F-term and D-term VEVs of singlet and U(1) R gauge fields, as well as by anomaly mediation, at a scale not far above the weak scale. We study the resulting pattern of supersymmetry breaking masses in detail, and find that it can be quite distinct. We construct classes of explicit models within this framework, based on higher dimensional unified theories with TeV-sized extra dimensions. A similar model based on a non-R symmetry is also presented. These models have a rich phenomenology at the TeV scale, and allow for detailed analyses of, e.g., electroweak symmetry breaking

  14. Preliminary survey of bee (Hymenoptera: Anthophila) richness in the northwestern Chihuahuan Desert

    Science.gov (United States)

    Robert L. Minckley; John S. Ascher

    2013-01-01

    Museum records indicate that the peak number of bee species occurs around the Mediterranean Sea and in the warm desert areas of North America, whereas flowering plants are most diverse in the tropics. We examine this biogeographic pattern for the bee species known from a limited area of northeastern Chihuahuan Desert, Mexico/United States. This topographically complex...

  15. Apparent Brecciation Gradient, Mount Desert Island, Maine

    Science.gov (United States)

    Hawkins, A. T.; Johnson, S. E.

    2004-05-01

    Mount Desert Island, Maine, comprises a shallow level, Siluro-Devonian igneous complex surrounded by a distinctive breccia zone ("shatter zone" of Gilman and Chapman, 1988). The zone is very well exposed on the southern and eastern shores of the island and provides a unique opportunity to examine subvolcanic processes. The breccia of the Shatter Zone shows wide variation in percent matrix and clast, and may represent a spatial and temporal gradient in breccia formation due to a single eruptive or other catastrophic volcanic event. The shatter zone was divided into five developmental stages based on the extent of brecciation: Bar Harbor Formation, Sols Cliffs breccia, Seeley Road breccia, Dubois breccia, and Great Head breccia. A digital camera was employed to capture scale images of representative outcrops using a 0.5 m square Plexiglas frame. Individual images were joined in Adobe Photoshop to create a composite image of each outcrop. The composite photo was then exported to Adobe Illustrator, which was used to outline the clasts and produce a digital map of the outcrop for analysis. The fractal dimension (Fd) of each clast was calculated using NIH Image and a Euclidean distance mapping method described by Bérubé and Jébrak (1999) to quantify the morphology of the fragments, or the complexity of the outline. The more complex the fragment outline, the higher the fractal dimension, indicating that the fragment is less "mature" or has had less exposure to erosional processes, such as the injection of an igneous matrix. Sols Cliffs breccia has an average Fd of 1.125, whereas Great Head breccia has an average Fd of 1.040, with the stages between having intermediate values. The more complex clasts of the Sols Cliffs breccia with a small amount (26.38%) of matrix material suggests that it is the first stage in a sequence of brecciation ending at the more mature, matrix-supported (71.37%) breccia of Great Head. The results of this study will be used to guide isotopic

  16. Radiatively-driven processes in forest fire and desert dust plumes

    Energy Technology Data Exchange (ETDEWEB)

    Weinzierl, Bernadett Barbara

    2008-07-01

    The absorption of solar radiation by atmospheric aerosol particles is important for the climate effects of aerosols. Absorption by aerosol particles heats atmospheric layers, even though the net effect for the entire atmospheric column may still be a cooling. Most experimental studies on absorbing aerosols so far focussed mainly on the aerosol properties and did not consider the influence of the aerosols on the thermodynamic structure of the atmosphere. In this study, data from two international aircraft field experiments, the Intercontinental Transport of Ozone and Precursors study (ITOP) 2004 and the Saharan Mineral Dust Experiment (SAMUM) 2006 are investigated. The ITOP data were collected before the work on this thesis started, while the logistics and the instrument preparation of the SAMUM campaign, the weather forecast during SAMUM and the in-situ aerosol measurements during SAMUM were done within this thesis. The experimental data are used to explore the impact of layers containing absorbing forest fire and desert dust aerosol particles on the atmospheric stability and the implications of a changed stability on the development of the aerosol microphysical and optical properties during long-range transport. For the first time, vertical profiles of the Richardson number Ri are used to assess the stability and mixing in forest fire and desert dust plumes. Also for the first time, the conclusions drawn from the observations of forest fire and desert dust aerosol, at first glance apparently quite different aerosol types, are discussed from a common perspective. Two mechanisms, the selfstabilising and the sealed ageing effect, acting in both forest fire and desert dust aerosol layers, are proposed to explain the characteristic temperature structure as well as the aerosol properties observed in lofted forest fire and desert dust plumes. The proposed effects impact on the ageing of particles within the plumes and reduce the plume dilution, therefore extending the

  17. Total vertical sediment flux and PM10 emissions from disturbed Chihuahuan Desert Surfaces

    Science.gov (United States)

    Desert surfaces are typically stable and represent some of the oldest landforms on Earth. For surfaces without vegetation, the evolution of a desert pavements of gravel protects the surface from erosive forces and vegetation further protects the surface in arid and semi-arid rangelands. The suscep...

  18. Silica in a Mars analog environment: Ka u Desert, Kilauea Volcano, Hawaii

    Science.gov (United States)

    Seelos, K.D.; Arvidson, R. E.; Jolliff, B.L.; Chemtob, S.M.; Morris, R.V.; Ming, D. W.; Swayze, G.A.

    2010-01-01

    Airborne Visible/Near-Infrared Imaging Spectrometer (AVIRIS) data acquired over the Ka u Desert are atmospherically corrected to ground reflectance and used to identify the mineralogic components of relatively young basaltic materials, including 250-700 and 200-400 year old lava flows, 1971 and 1974 flows, ash deposits, and solfatara incrustations. To provide context, a geologic surface units map is constructed, verified with field observations, and supported by laboratory analyses. AVIRIS spectral endmembers are identified in the visible (0.4 to 1.2 ??m) and short wave infrared (2.0 to 2.5 ??m) wavelength ranges. Nearly all the spectral variability is controlled by the presence of ferrous and ferric iron in such minerals as pyroxene, olivine, hematite, goethite, and poorly crystalline iron oxides or glass. A broad, nearly ubiquitous absorption feature centered at 2.25 ??m is attributed to opaline (amorphous, hydrated) silica and is found to correlate spatially with mapped geologic surface units. Laboratory analyses show the silica to be consistently present as a deposited phase, including incrustations downwind from solfatara vents, cementing agent for ash duricrusts, and thin coatings on the youngest lava flow surfaces. A second, Ti-rich upper coating on young flows also influences spectral behavior. This study demonstrates that secondary silica is mobile in the Ka u Desert on a variety of time scales and spatial domains. The investigation from remote, field, and laboratory perspectives also mimics exploration of Mars using orbital and landed missions, with important implications for spectral characterization of coated basalts and formation of opaline silica in arid, acidic alteration environments. Copyright 2010 by the American Geophysical Union.

  19. Spatial and temporal changes in desertification in the southern region of the Tengger Desert from 1973 to 2009

    Science.gov (United States)

    Guan, Qingyu; Guan, Wenqian; Yang, Jing; Zhao, Shilei; Pan, Baotian; Wang, Lei; Song, Na; Lu, Min; Li, Fuchun

    2017-07-01

    The sandy land in the southern region of the Tengger Desert is adjacent to cities and towns, and land desertification poses a threat to the livelihood and production of local residents. To determine dynamic changes in local desertification, five periods (1973, 1987, 1992, 2001, and 2009) of remote sensing data are studied by remote sensing (RS) and geographic information system (GIS). The desert contraction area is primarily centered around three units (Wuwei, Gulang, and Jingtai) and nearby regions of Zhongwei City. The primary desert expansion areas include the west side of Helan Mountain (WSHM), the Central Mountainous Area (CMA), and the eastern and western Zhongwei units far from towns. From 1973 to 2009, the degree of change in the contracting part of the primary desert expansion unit showed an increasing trend; in brief, most of the desert (especially after 2001) has been developing in a direction in which desertification has been gradually controlled. The primary desert expansion areas are less affected by human activity, but they are primarily controlled by natural factors (especially wind and terrain). The desert contraction areas occur around the towns and nearby regions with frequent human activity; desertification is primarily controlled by human factors. With rapid economic development (especially after 2000), the scale of the cultivated area, town, and ecological protection engineering has gradually expanded, and the latter two are primarily built on a previous desert, which is the root cause of the reduction in the desert areas around the towns and the shrinkage toward north of border. Therefore, reasonable and effective human activity in the southern region of the Tengger Desert is playing a crucial role in preventing desertification.

  20. Real-Time Monitoring of Mountain Conifer Growth Response to Seasonal Climate and the Summer Monsoon in the Great Basin of North America

    Science.gov (United States)

    Strachan, S.; Biondi, F.

    2013-12-01

    Tree rings in the American intermountain west are often used for palaeoclimatic purposes, including reconstructions of precipitation, temperature, and drought. Specific seasonal phenomena such as the North American Monsoon (NAM) are also being identified in tree-ring studies as being related to certain growth features in the rings (such as early-onset 'false' latewood). These relationships have historically been developed using statistical relationships between tree-ring chronologies and regional weather observations. In zones near the periphery of the NAM, summertime precipitation may be more sporadic, yet localized vegetation assemblages in the northern Mojave desert and Great Basin regions indicate that these events are still important for some ecosystems which have established in areas where NAM activity is present. Major shifts in NAM behavior in the past may have been recorded by tree rings, and identifying the specific mechanisms/circumstances by which this occurs is critical for efforts seeking to model ecosystem response to climate changes. By establishing in-situ monitoring of climate/weather, soils, and tree-growth variables in Pinus ponderosa scopulorum and Pinus monophylla zones at study sites in eastern/southern Nevada, we are able to address these issues at very fine spatial and temporal scales. Data from two seasons of monitoring precipitation, solar radiation, air temperature, soil temperature, soil water content, tree sap flow, tree radial distance increment, and hourly imagery are presented. Point dendrometers along with sap flow sensors monitor growth in these ponderosa pine around the clock to help researchers understand tree-ring/climate relationships.

  1. Validation of SWEEP for creep, saltation, and suspension in a desert-oasis ecotone

    Science.gov (United States)

    Wind erosion in the desert-oasis ecotone can accelerate desertification and thus impacts oasis ecological security. Little is known about the susceptibility of the desert-oasis ecotone to wind erosion in the Tarim Basin even though the ecotone is a major source of windblown dust in China. The object...

  2. Time-varying span efficiency through the wingbeat of desert locusts.

    Science.gov (United States)

    Henningsson, Per; Bomphrey, Richard J

    2012-06-07

    The flight performance of animals depends greatly on the efficacy with which they generate aerodynamic forces. Accordingly, maximum range, load-lifting capacity and peak accelerations during manoeuvres are all constrained by the efficiency of momentum transfer to the wake. Here, we use high-speed particle image velocimetry (1 kHz) to record flow velocities in the near wake of desert locusts (Schistocerca gregaria, Forskål). We use the measured flow fields to calculate time-varying span efficiency throughout the wing stroke cycle. The locusts are found to operate at a maximum span efficiency of 79 per cent, typically at a plateau of about 60 per cent for the majority of the downstroke, but at lower values during the upstroke. Moreover, the calculated span efficiencies are highest when the largest lift forces are being generated (90% of the total lift is generated during the plateau of span efficiency) suggesting that the combination of wing kinematics and morphology in locust flight perform most efficiently when doing the most work.

  3. Ecosystem responses to warming and watering in typical and desert steppes

    OpenAIRE

    Zhenzhu Xu; Yanhui Hou; Lihua Zhang; Tao Liu; Guangsheng Zhou

    2016-01-01

    Global warming is projected to continue, leading to intense fluctuations in precipitation and heat waves and thereby affecting the productivity and the relevant biological processes of grassland ecosystems. Here, we determined the functional responses to warming and altered precipitation in both typical and desert steppes. The results showed that watering markedly increased the aboveground net primary productivity (ANPP) in a typical steppe during a drier year and in a desert steppe over two ...

  4. Vegetation - Anza-Borrego Desert State Park [ds165

    Data.gov (United States)

    California Natural Resource Agency — The Anza Borrego Desert State Park (ABDSP) Vegetation Map depicts vegetation within the Park and its surrounding environment. The map was prepared by the Department...

  5. Fire Impacts on the Mojave Desert Ecosystem: Literature Review

    Energy Technology Data Exchange (ETDEWEB)

    Fenstermaker Lynn

    2012-01-01

    The Nevada National Security Site (NNSS) is located within the Mojave Desert, which is the driest region in North America. Precipitation on the NNSS varies from an annual average of 130 millimeters (mm; 5.1 inches) with a minimum of 47 mm (1.9 inches) and maximum of 328 mm (12.9 inches) over the past 15 year period to an annual average of 205 mm (8.1 inches) with an annual minimum of 89 mm (3.5 inches) and maximum of 391 mm (15.4 inches) for the same time period; for a Frenchman Flat location at 970 meters (m; 3182 feet) and a Pahute Mesa location at 1986 m (6516 feet), respectively. The combination of aridity and temperature extremes has resulted in sparsely vegetated basins (desert shrub plant communities) to moderately vegetated mountains (mixed coniferous forest plant communities); both plant density and precipitation increase with increasing elevation. Whereas some plant communities have evolved under fire regimes and are dependent upon fire for seed germination, plant communities within the Mojave Desert are not dependent on a fire regime and therefore are highly impacted by fire (Brown and Minnich, 1986; Brooks, 1999). As noted by Johansen (2003) natural range fires are not prevalent in the Mojave and Sonoran Deserts because there is not enough vegetation present (too many shrub interspaces) to sustain a fire. Fire research and hence publications addressing fires in the Southwestern United States (U.S.) have therefore focused on forest, shrub-steppe and grassland fires caused by both natural and anthropogenic ignition sources. In the last few decades, however, invasion of mid-elevation shrublands by non-native Bromus madritensis ssp. rubens and Bromus tectorum (Hunter, 1991) have been highly correlated with increased fire frequency (Brooks and Berry, 2006; Brooks and Matchett, 2006). Coupled with the impact of climate change, which has already been shown to be playing a role in increased forest fires (Westerling et al., 2006), it is likely that the fire

  6. Diversity of bacteria nesting the plant cover of north Sinai deserts, Egypt

    Directory of Open Access Journals (Sweden)

    Amira L. Hanna

    2013-01-01

    Full Text Available North Sinai deserts were surveyed for the predominant plant cover and for the culturable bacteria nesting their roots and shoots. Among 43 plant species reported, 13 are perennial (e.g. Fagonia spp., Pancratium spp. and 30 annuals (e.g. Bromus spp., Erodium spp.. Eleven species possessed rhizo-sheath, e.g. Cyperus capitatus, Panicum turgidum and Trisetaria koelerioides. Microbiological analyses demonstrated: the great diversity and richness of associated culturable bacteria, in particular nitrogen-fixing bacteria (diazotrophs; the majority of bacterial residents were of true and/or putative diazotrophic nature; the bacterial populations followed an increasing density gradient towards the root surfaces; sizeable populations were able to reside inside the root (endorhizosphere and shoot (endophyllosphere tissues. Three hundred bacterial isolates were secured from studied spheres. The majority of nitrogen-fixing bacilli isolates belonged to Bacillus megaterium, Bacillus pumilus, Bacillus polymexa, Bacillus macerans, Bacillus circulans and Bacillus licheniformis. The family Enterobacteriaceae represented by Enterobacter agglomerans, Enterobacter sackazakii, Enterobacter cloacae, Serratia adorifera, Serratia liquefaciens and Klebsiella oxytoca. The non-Enterobacteriaceae population was rich in Pantoae spp., Agrobacterium rdiobacter, Pseudomonas vesicularis, Pseudomonas putida, Stenotrophomonas maltophilia, Ochrobactrum anthropi, Sphingomonas paucimobilis and Chrysemonas luteola. Gluconacetobacter diazotrophicus were reported inside root and shoot tissues of a number of tested plants. The dense bacterial populations reported speak well to the very possible significant role played by the endophytic bacterial populations in the survival, in respect of nutrition and health, of existing plants. Such groups of diazotrophs are good candidates, as bio-preparates, to support the growth of future field crops grown in deserts of north Sinai and irrigated by the

  7. A Deafening Silence: Hizballah After the American Invasion of Iraq

    National Research Council Canada - National Science Library

    Wrona, Jr, Richard M

    2007-01-01

    ... American servicemen and twenty-three French soldiers. Further bombings, murders, and kidnappings greatly contributed to the American decision months later that the carnage and anarchy in Lebanon were not worth additional American lives...

  8. Geospatial techniques to Identify the Location of Farmers Markets and Community Gardens within Food Deserts in Virginia

    Science.gov (United States)

    Sriharan, S.; Meekins, D.; Comar, M.; Bradshaw, S.; Jackson, L.

    2017-12-01

    Specifically, a food desert is defined as an area where populations live more than one mile from a supermarket or large grocery store if in an urban area or more than 10 miles from a supermarket or large grocery store if in a rural area (Ver Ploeg et al. 2012). According to the U.S. Department of Agriculture, a food desert is "an area in the United States with limited access to affordable and nutritious food, particularly such an area composed of predominately lower-income neighborhoods and communities" (110th Congress 2008). Three fourths of these food deserts are urban. In the Commonwealth of Virginia, Petersburg City is among the eight primary localities, where its population is living in a food desert. This project will compare those identified food deserts in Virginia (areas around Virginia State University) with focus to where farmers markets and community gardens are being established. The hypothesis of this study is that these minority groups do not get healthy food due to limited access to grocery stores and superstores. To address this problem, the community development activities should focus on partnering local Petersburg convenience stores with farmers and community gardeners to sell fresh produce. Existing data was collected on convenient stores and community gardens in Petersburg City and Chesterfield County. Rare data was generated for Emporia, Lynchburg and Hopewell. The data was compiled through field work and mapping with ArcGIS where markets and gardens are being established, and create a spatial analysis of their location We have localities that reflect both rural and urban areas. The project provides educational support for students who will find solution to community problems by developing activities to: (a) define and examine characteristics of food deserts, (b) identify causes and consequences of food deserts and determine if their community is a food desert, (c) research closest food desert to their school, and (d) design solutions to help

  9. Barriers to Food Security and Community Stress in an Urban Food Desert

    Directory of Open Access Journals (Sweden)

    Jessica Crowe

    2018-05-01

    Full Text Available By analyzing data from focus groups in a poor, mostly African American neighborhood in a large U.S. city, we describe how residents in urban food deserts access food, the barriers they experience in accessing nutritious, affordable food, and how community food insecurity exacerbates prior social, built, and economic stressors. Provided the unwillingness of supermarkets and supercenters to locate to poor urban areas and the need for nutritious, affordable food, it may be more efficient and equitable for government programs to financially partner with ethnic markets and smaller locally-owned grocery stores to increase the distribution and marketing of healthy foods rather than to spend resources trying to entice a large supermarket to locate to the neighborhood. By focusing on improving the conditions of the neighborhood and making smaller grocery stores and markets more affordable and produce more attractive to residents, the social, built, and economic stressors experienced by residents will be reduced, thereby possibly improving overall mental and physical health.

  10. Thermal design of a fully equipped solar-powered desert home

    KAUST Repository

    Serag-Eldin, M.A.

    2010-03-01

    The paper presents a conceptual design and thermodynamic analysis of a solar-powered desert home. The home is airconditioned and provides all modern comforts and facilities. Electrical power, which drives the entire energy system, is generated by roof mounted photovoltaic modules. A detailed dynamic heat transfer analysis is conducted for the building envelope, coupled with a solar radiation model. A dynamic heat balance for a typical Middle-Eastern desert site, reveals that indeed such a design is feasible with present day technology; and should be even more attractive with future advances in technology.

  11. At Home in the Great Northern Wilderness: African Americans and Freedom’s Ecology in the Adirondacks, 1846-1859

    Directory of Open Access Journals (Sweden)

    Daegan Miller

    2013-05-01

    Full Text Available In the fall of 1846, the first of 3,000 African American settlers set foot on their 40-acre plots in the Great Northern Wilderness of New York State, a place we now call the “forever wild” wilderness of the Adirondack State Park. These black settlers were the initial wave of a social experiment meant to destroy both slavery and, more generally, racism throughout the entire United States through the redemptive practice of a utopian agrarianism. The settlers understood that nature and culture, wilderness and society, were thickly, dialectically intertwined. And they weren’t alone: their efforts were seeded by the white abolitionist, Gerrit Smith; fertilized by the utopian socialist communes that covered the Northeast in the 1840s; and nurtured by abolitionists, both black and white. To United States environmental history, I add two threads less frequently seen: African American history and an intellectual history of radical politics. Following these threads has led me beyond the disciplinary confines of history and into larger debates about the cultural politics of wilderness. In this article I argue that the critical wilderness paradigm currently reigning both in and beyond historical scholarship has obscured nuanced, sometimes radical visions of the natural world. Instead of an ironic, deconstructed notion of a troubling wilderness, I suggest another heuristic, the ecology of freedom, which highlights past contingency and hope, and can furthermore help guide our present efforts, both scholastic and activist, to find an honorable, just way of living on the earth.

  12. A New Infrared Desert Dust Index over French Guyana Rain forest: First results

    Science.gov (United States)

    Molinie, J.; Barnacin, E.; Henry, J. L.; Gobinddass, M. L.; Panechou-Pulcherie, K.; Feuillard, T.; Nagau, J.

    2017-12-01

    Recently a NASA researcher showed the role of desert dust contribution for the Amazonian rain forest. In another hand, desert dust impact population health when PM 10 level reached values around and upper the PM 10 threshold of the 50 µg m-3, established by the World Health Organization (WHO). Infrared Desert Dust Index (IDDI) developed by Legrand with Meteosat infrared images, allow the following of desert dust plumes over semi-arid land. In French Guiana the WHO threshold is currently overpass in measurements done by ORA air quality network, in the two main towns located close to the coast. For inland population, it is very difficult to have continuous dust measures due to the low infrastructure supplies. We need to develop a tools in order to follow the crossing of desert dust over the French Guyana rain forest, from the coast to inland villages. Following the IDDI concept and comparing with VIIRS AOT EDR result over the same area, a modified IDDI for Amazonian region (IDDI_A) has been proposed to identify the dusty pixels over the forest. Despite of high cloud presence, a good correlation between AOT EDR and IDDI_A was obtained. The IDDI_A calculation has been applied over French Guiana area for different PM 10 level at Cayenne, a town along the coast.

  13. Characterizing dust aerosols in the atmospheric boundary layer over the deserts in Northwest China: monitoring network and field observation

    Science.gov (United States)

    He, Q.; Matimin, A.; Yang, X.

    2016-12-01

    TheTaklimakan, Gurbantunggut and BadainJaran Deserts with the total area of 43.8×104 km2 in Northwest China are the major dust emission sources in Central Asia. Understanding Central Asian dust emissions and the interaction with the atmospheric boundary layer has an important implication for regional and global climate and environment changes. In order to explore these scientific issues, a monitoring network of 63 sites was established over the vast deserts (Taklimakan Desert, Gurbantunggut Desert and Badain Jaran Desert) in Northwest China for the comprehensive measurements of dust aerosol emission, transport and deposition as well as the atmospheric boundary layer including the meteorological parameters of boundary layer, surface radiation, surface heat fluxes, soil parameters, dust aerosol properties, water vapor profiles, and dust emission. Based on the monitoring network, the field experiments have been conducted to characterize dust aerosols and the atmospheric boundary layer over the deserts. The experiment observation indicated that depth of the convective boundary layer can reach 5000m on summer afternoons. In desert regions, the diurnal mean net radiation was effected significantly by dust weather, and sensible heat was much greater than latent heat accounting about 40-50% in the heat balance of desert. The surface soil and dust size distributions of Northwest China Deserts were obtained through widely collecting samples, results showed that the dominant dust particle size was PM100within 80m height, on average accounting for 60-80% of the samples, with 0.9-2.5% for PM0-2.5, 3.5-7.0% for PM0-10 and 5.0-14.0% for PM0-20. The time dust emission of Taklimakan Desert, Gurbantunggut Desert and Badain Jaran Desert accounted for 0.48%, 7.3%×10-5and 1.9% of the total time within a year, and the threshold friction velocity for dust emission were 0.22-1.06m/s, 0.29-1.5m/s and 0.21-0.59m/s, respectively.

  14. Translocation as a conservation tool for Agassiz's desert tortoises: Survivorship, reproduction, and movements

    Science.gov (United States)

    K. E. Nussear; C. R. Tracy; P. A. Medica; D. S. Wilson; R. W. Marlow; P. S. Corn

    2012-01-01

    We translocated 120 Agassiz's desert tortoises to 5 sites in Nevada and Utah to evaluate the effects of translocation on tortoise survivorship, reproduction, and habitat use. Translocation sites included several elevations, and extended to sites with vegetation assemblages not typically associated with desert tortoises in order to explore the possibility of moving...

  15. 78 FR 143 - Desert Mining, Inc., Eagle Broadband, Inc., Endovasc, Inc., Environmental Oil Processing...

    Science.gov (United States)

    2013-01-02

    ... SECURITIES AND EXCHANGE COMMISSION [File No. 500-1] Desert Mining, Inc., Eagle Broadband, Inc., Endovasc, Inc., Environmental Oil Processing Technology Corp., Falcon Ridge Development, Inc., Fellows... that there is a lack of current and accurate information concerning the securities of Desert Mining...

  16. A Research Note on American Indian Criminal Justice

    Science.gov (United States)

    Braunstein, Rich; Anderson, Bill

    2008-01-01

    One confronts many difficulties when conducting policy-relevant criminal justice research that focuses on American Indian interests. Foremost among these difficulties is the great variation in relevant contexts that apply to this area of research. From the urban context of large American cities, where American Indians constitute a slim minority…

  17. Ozone Transport Aloft Drives Surface Ozone Maxima Across the Mojave Desert

    Science.gov (United States)

    VanCuren, R. A.

    2014-12-01

    A persistent layer of polluted air in the lower free troposphere over the Mojave Desert (California and Nevada) drives spring and summer surface ozone maxima as deep afternoon mixing delivers ozone and ozone precursors to surface measurement sites 200 km or more downwind of the mountains that separate the deserts from the heavily populated coastal areas of California. Pollutants in this elevated layer derive from California source regions (the Los Angeles megacity region and the intensive agricultural region of the San Joaquin Valley), and from long-range transport from Asia. Recognition of this poorly studied persistent layer explains and expands the significance of previously published reports of ozone and other pollutants observed in and over the Mojave Desert, resolves an apparent paradox in the timing of ozone peaks due to transport from the upwind basins, and provides a new perspective on the long-range downwind impacts of megacity pollution plumes.

  18. Influence of shrubs on soil chemical properties in Alxa desert steppe, China

    Science.gov (United States)

    Hua Fu; Shifang Pei; Yaming Chen; Changgui Wan

    2007-01-01

    Alxa desert steppe is one of severely the degraded rangelands in the Northwest China. Shrubs, as the dominant life form in the desert steppe, play an important role in protecting this region from further desertification. Chemical properties of three soil layers (0 to 10, 10 to 20 and 20 to 30 cm) at three locations (the clump center [A], in the periphery of shrub...

  19. Should I stay or should I go? Female brood desertion and male counterstrategy in rock sparrows

    DEFF Research Database (Denmark)

    Griggio, Matteo; Matessi, Giuliano; Pilastro, Andrea

    2005-01-01

    petronia), a species in which females can desert their first brood before the nestlings from the first brood leave the nest. We predicted that the male would either desert the brood first or stay even if this implied the risk of caring for the brood alone. We found that males mated to loaded females did...... not leave but stayed and significantly increased their courtship rate and mate guarding. Unexpectedly, they also increased their food provisioning to the nestlings, even though loaded females did not reduce their nestling-feeding rate. The increase in male feeding rate may be explained as a way for the male...... to reduce the female's propensity to switch mate and desert or to increase her propensity to copulate with the male to obtain paternity in her next brood. Altogether, our results demonstrate that the perception of the risk of being deserted by the female does not necessarily induce males to desert first...

  20. On American Cultural Exportation Strategy

    Institute of Scientific and Technical Information of China (English)

    李德俊

    2015-01-01

    American government has been attaching great importance to the role that cultural values plays in international relationships and Culture Exportation has gradually become one of the important parts of American diplomatic strategy. This strategy,which is propelled by a variety of impetuses and conducted by different approaches,is mainly aimed to serve the overall national interests of the United States.

  1. On American Cultural Exportation Strategy

    Institute of Scientific and Technical Information of China (English)

    李德俊

    2015-01-01

    American government has been attaching great importance to the role that cultural values plays in international relationships and Culture Exportation has gradually become one of the important parts of American diplomatic strategy.This strategy,which is propelled by a variety of impetuses and conducted by different approaches,is mainly aimed to serve the overall national interests of the United States.

  2. A Study to Determine the Mental Models in Preschool Children’s Conceptualization of a Desert Environment

    Directory of Open Access Journals (Sweden)

    Berat AHİ

    2016-03-01

    Full Text Available This study aimed to determine mental models and identify codes (schemes used in conceptualizing a desert environment. The sample for this study consisted of 184 – out of a total population of 3,630 - children in preschool education in the central district of Kastamonu, Turkey. Within the scope of this study, the children were initially asked to draw a desert-themed picture, followed by a semi-structured interview to seek their opinions about the drawing and clarify what a desert environment meant to them. According to the findings, the children referred to 38 different codes relevant to the conceptualization of a desert environment; the most frequently used were the sun (f= 160, 86.9%, sand (f= 100, 54.3%, cacti (f= 74, 35.3% and camels (f= 52, 28.6%. During the interview phase, 33 children described a desert as a place where there is no life, although a significant number of the children (f= 65, 39.1% did describe a desert as a place where plants and animals live. Moreover, the sun and its rays were disproportionately bigger in size, in order to emphasize the excessive heat associated with the specific ecosystem found in a desert environment; to reinforce this, humans drenched in sweat, the absence of trees and the prevalence of cacti and exotic wildlife, including camels, scorpions and lizards, were all features of the children’s drawings. Based on these findings, it was inferred that the mental models in some of the children (f= 72, 39.1% were scientifically informed, with a degree of accuracy, about a desert environment. On the basis of the findings, it is considered that determining mental models in children in relation to different ecological concepts can be beneficial to teachers and curriculum programmers involved in environmental education.

  3. A study to determine the mental models in preschool children’s conceptualization of a desert environment

    Directory of Open Access Journals (Sweden)

    Berat Ahi

    2016-03-01

    Full Text Available This study aimed to determine mental models and identify codes (schemes used in conceptualizing a desert environment. The sample for this study consisted of 184 – out of a total population of 3,630 - children in preschool education in the central district of Kastamonu, Turkey. Within the scope of this study, the children were initially asked to draw a desert-themed picture, followed by a semi-structured interview to seek their opinions about the drawing and clarify what a desert environment meant to them. According to the findings, the children referred to 38 different codes relevant to the conceptualization of a desert environment; the most frequently used were the sun (f= 160, 86.9%, sand (f= 100, 54.3%, cacti (f= 74, 35.3% and camels (f= 52, 28.6%. During the interview phase, 33 children described a desert as a place where there is no life, although a significant number of the children (f= 65, 39.1% did describe a desert as a place where plants and animals live. Moreover, the sun and its rays were disproportionately bigger in size, in order to emphasize the excessive heat associated with the specific ecosystem found in a desert environment; to reinforce this, humans drenched in sweat, the absence of trees and the prevalence of cacti and exotic wildlife, including camels, scorpions and lizards, were all features of the children’s drawings. Based on these findings, it was inferred that the mental models in some of the children (f= 72, 39.1% were scientifically informed, with a degree of accuracy, about a desert environment. On the basis of the findings, it is considered that determining mental models in children in relation to different ecological concepts can be beneficial to teachers and curriculum programmers involved in environmental education.

  4. 76 FR 50493 - Notice of Availability of the Record of Decision for the Desert Sunlight Holdings, LLC, Desert...

    Science.gov (United States)

    2011-08-15

    ... DEPARTMENT OF THE INTERIOR Bureau of Land Management [CACA-48649, LLCAD06000 L51010000 ER0000... right-of-way (ROW) application CACA-48649 for the Desert Sunlight Solar Farm Project (DSSF). The DSSF is... (CACA-052682) where the project would interconnect with the SCE regional transmission system. The DSSF...

  5. Mapping Palaeohydrography in Deserts: Contribution from Space-Borne Imaging Radar

    Directory of Open Access Journals (Sweden)

    Philippe Paillou

    2017-03-01

    Full Text Available Space-borne Synthetic Aperture Radar (SAR has the capability to image subsurface features down to several meters in arid regions. A first demonstration of this capability was performed in the Egyptian desert during the early eighties, thanks to the first Shuttle Imaging Radar mission. Global coverage provided by recent SARs, such as the Japanese ALOS/PALSAR sensor, allowed the mapping of vast ancient hydrographic systems in Northern Africa. We present a summary of palaeohydrography results obtained using PALSAR data over large deserts such as the Sahara and the Gobi. An ancient river system was discovered in eastern Lybia, connecting in the past the Kufrah oasis to the Mediterranean Sea, and the terminal part of the Tamanrasett river was mapped in western Mauritania, ending with a large submarine canyon. In southern Mongolia, PALSAR images combined with topography analysis allowed the mapping of the ancient Ulaan Nuur lake. We finally show the potentials of future low frequency SAR sensors by comparing L-band (1.25 GHz and P-band (435 MHz airborne SAR acquisitions over a desert site in southern Tunisia.

  6. Preventing desert locust plagues: optimizing management interventions

    NARCIS (Netherlands)

    Huis, van A.; Cressman, K.; Magor, J.I.

    2007-01-01

    Solitarious desert locusts, Schistocerca gregaria (Forskål) (Orthoptera: Acrididae), inhabit the central, arid, and semi-arid parts of the species¿ invasion area in Africa, the Middle East, and South-West Asia. Their annual migration circuit takes them downwind to breed sequentially where winter,

  7. Divining Jordan's desert waters | IDRC - International Development ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    ... in the area have a long history of being water-conservers, and the idea of using the ... Dr Abu-Jaber examined is covered by an ancient, volcanic rock called basalt. ... When a desert cloudburst drops rain on the area, the raindrops quickly roll ...

  8. A Proposal for Desert House Design in Egypt Using Passive Ground Cooling Techniques

    Directory of Open Access Journals (Sweden)

    Mohamed Medhat Dorra

    2018-06-01

    Full Text Available An area less than 5.5% of Egyptian territory is where most of Egypt‘s population lives in. A narrow strip of land forms the Nile Valley and Delta sector.The National Project for Desert Hinterlands is one of the urban projects targeting rehabilitation of the poor in alternative villages in the near desert to stop urban sprawl over agricultural land and decrease the congestion in the old habitats. Low cost energy efficient houses are the aim of the architect in similar projects taking in consideration the high electricity consumption of Egypt’s residential sector. Based on a literature review, this paper presents a proposal for designing desert dwellings   that accommodates the hot dry climate by incorporating passive elements and using stabilized earth blocks as a local building material. Furthermore, simulation is used to test alternative proposals. The results show that an underground constructed house with a sunken courtyard incorporating an Earth to Air Heat Exchanger System (EAHE can reduce between 42-72% of energy consumption used to achieve thermal comfort compared to contemporary desert housing projects.

  9. Difference in luminescence sensitivity of coarse-grained quartz from deserts of northern China

    International Nuclear Information System (INIS)

    Zheng, C.X.; Zhou, L.P.; Qin, J.T.

    2009-01-01

    The luminescence sensitivity of coarse quartz extracted from desert sands in northern China was investigated. In general, the western deserts' samples are shown to be less sensitive than samples from the eastern deserts with respect to both OSL and the 110 deg. C TL peak. However, internal scatter among different aliquots of the same sample is observed for these two signals, which have already been normalized by weight. Laboratory dosing/bleach experiments indicate that earth surface processes, such as repeated burial and transportation can cause the sensitivity change and suggest that they may be responsible for the internal scatter. An intrinsic property of quartz was explored via the luminescence response to thermal activation to a maximum temperature of 700 deg. C. The thermal activation curves obtained with quartz from western and central deserts are similar, except one sample from Gurbantungut, which follows the pattern of eastern samples. The differences in quartz luminescence sensitivity exhibited by OSL/110 deg. C TL sensitivity and response to thermal activation are in accordance with the published results of geochemical studies.

  10. Water sources for cyanobacteria below desert rocks in the Negev Desert determined by conductivity

    OpenAIRE

    McKay, Christopher P.

    2016-01-01

    We present year round meteorological and conductivity measurements of colonized hypolithic rocks in the Arava Valley, Negev Desert, Israel. The data indicate that while dew is common in the Negev it is not an important source of moisture for hypolithic organisms at this site. The dominance of cyanobacteria in the hypolithic community is consistent with predictions that cyanobacteria are confined to habitats supplied by rain. To monitor the presence of liquid water under the small Negev rocks ...

  11. Water relations and photosynthesis in the cryptoendolithic microbial habitat of hot and cold deserts

    Science.gov (United States)

    Palmer, R. J. Jr; Friedmann, E. I.

    1990-01-01

    Two cryptoendolithic microbial communities, lichens in the Ross Desert of Antarctica and cyanobacteria in the Negev Desert, inhabit porous sandstone rocks of similar physical structure. Both rock types adsorb water vapor by physical mechanisms unrelated to biological processes. Yet the two microbial communities respond differently to water stress: cryptoendolithic lichens begin to photosynthesize at a matric water potential of -46.4 megaPascals (MPa) [70% relative humidity (RH) at 8 degrees C], resembling thallose desert lichens. Cryptoendolithic cyanobacteria, like other prokaryotes, photosynthesize only at very high matric water potentials [> -6.9 MPa, 90% RH at 20 degrees C].

  12. Windblown sediment transport and loss in a desert-oasis ecotone in the Tarim Basin.

    Science.gov (United States)

    Pi, Huawei; Sharratt, Brenton; Lei, Jiaqiang

    2017-08-10

    The Tarim Basin is regarded as one of the most highly erodible areas in China. Desert comprises 64% of the land use in the Basin, but the desert-oasis ecotone plays a prominent role in maintaining oasis ecological security and stability. Yet, little is known concerning the magnitude of windblown sediment transport in a desert-oasis ecotone. Therefore, aeolian sediment transport and loss was assessed from a desert-oasis experimental site located near Alaer City in the northwestern Tarim Basin. Sediment transport and factors governing transport were measured during three high wind events in 2012 and four events in 2013. Sediment transport was measured to a height of 10 m using passive aeolian airborne sediment samplers. The mass flux profile over the eroding surface was well represented by the power-law (R 2  > 0.77). Sediment loss from the site ranged from 118 g m -2 for the 20-24Apr 2012 wind event to 2925 g m -2 for the 31Mar-11Apr 2012 event. Suspension accounted for 67.4 to 84.8% of sediment loss across all high wind events. Our results indicate the severity of wind erosion in a desert-oasis ecotone and thus encourage adoption of management practices that will enhance oasis ecological security.

  13. [Risk factors for students desertion from the UASLP School of Medicine, México].

    Science.gov (United States)

    Hernández-Mata, José María; Hernández-Castro, Rodrigo; Nieto-Caraveo, Amado; Hernández-Sierra, Juan Francisco

    2005-01-01

    To obtain the profile of students that deserted from the Faculty of Medicine of the Autonomous University of San Luis Potosi, México. Cases and controls nested in a cohort. All students that voluntarily deserted between 1992 and 2002 were consulted. Each student was compared in an aleatory form with a regular student and a proper questionnaire was applied. The significantly associated factors to abandon the Faculty of Medicine were: high school of origin (OR=2.43), extra-ordinary exam (OR=3.13), and lack of vocation (OR=2.41). The subjacent factors for not deserting from the Faculty of Medicine were: study habits, capacity for sustained effort, and tolerance to frustration.

  14. Disturbance to desert soil ecosystems contributes to dust-mediated impacts at regional scales

    Science.gov (United States)

    Pointing, Stephen B.; Belnap, Jayne

    2014-01-01

    This review considers the regional scale of impacts arising from disturbance to desert soil ecosystems. Deserts occupy over one-third of the Earth’s terrestrial surface, and biological soil covers are critical to stabilization of desert soils. Disturbance to these can contribute to massive destabilization and mobilization of dust. This results in dust storms that are transported across inter-continental distances where they have profound negative impacts. Dust deposition at high altitudes causes radiative forcing of snowpack that leads directly to altered hydrological regimes and changes to freshwater biogeochemistry. In marine environments dust deposition impacts phytoplankton diazotrophy, and causes coral reef senescence. Increasingly dust is also recognized as a threat to human health.

  15. Desert Peak East Enhanced Geothermal Systems (EGS) Project

    Energy Technology Data Exchange (ETDEWEB)

    Zemach, Ezra [Ormat Technologies Inc., Reno, NV (United States); Drakos, Peter [Ormat Technologies Inc., Reno, NV (United States); Spielman, Paul [Ormat Technologies Inc., Reno, NV (United States); Akerley, John [Ormat Technologies Inc., Reno, NV (United States)

    2013-09-30

    This manuscript is a draft to replaced with a final version at a later date TBD. A summary of activities pertaining to the Desert Peak EGS project including the planning and resulting stimulation activities.

  16. Ground-water quality and geochemistry, Carson Desert, western Nevada

    Science.gov (United States)

    Lico, Michael S.; Seiler, R.L.

    1994-01-01

    Aquifers in the Carson Desert are the primary source of drinking water, which is highly variable in chemical composition. In the shallow basin-fill aquifers, water chemistyr varies from a dilute calcium bicarbonate-dominated water beneath the irrigated areas to a saline sodium chloride- dominated water beneath unirrigated areas. Water samples from the shallow aquifers commonly have dissolved solids, chloride, magnesium, sulfate, arsenic, and manganese concentrations that exceed State of Nevada drinking-water standards. Water in the intermediante basin-fill aquifers is a dilute sodium bicarbonate type in the Fallon area and a distinctly more saline sodium chloride type in the Soda Lake-Upsal Hogback area. Dissolved solids, chloride, arsenic, fluoride, and manganese concen- trations commonly exceed drinking-water standards. The basalt aquifer contains a dilute sodium bicarbonate chloride water. Arsenic concentrations exceed standards in all sampled wells. The concen- trations of major constituents in ground water beneath the southern Carson Desert are the result of evapotranspiration and natural geochemical reactions with minerals derived mostly from igneous rocks. Water with higher concentrations of iron and manganese is near thermodynamic equilibrium with siderite and rhodochrosite and indicates that these elements may be limited by the solubility of their respective carbonate minerals. Naturally occurring radionuclides (uranium and radon-222) are present in ground water from the Carson Desert in concen- tratons higher than proposed drinking-water standards. High uranium concentrations in the shallow aquifers may be caused by evaporative concentration and the release of uranium during dissolution of iron and manganese oxides or the oxidation of sedimentary organic matter that typically has elevated uranium concentrations. Ground water in the Carson Desert does not appear to have be contaminated by synthetic organic chemicals.

  17. Molecular mechanisms of foliar water uptake in a desert tree.

    Science.gov (United States)

    Yan, Xia; Zhou, Maoxian; Dong, Xicun; Zou, Songbing; Xiao, Honglang; Ma, Xiao-Fei

    2015-11-12

    Water deficits severely affect growth, particularly for the plants in arid and semiarid regions of the world. In addition to precipitation, other subsidiary water, such as dew, fog, clouds and small rain showers, may also be absorbed by leaves in a process known as foliar water uptake. With the severe scarcity of water in desert regions, this process is increasingly becoming a necessity. Studies have reported on physical and physiological processes of foliar water uptake. However, the molecular mechanisms remain less understood. As major channels for water regulation and transport, aquaporins (AQPs) are involved in this process. However, due to the regulatory complexity and functional diversity of AQPs, their molecular mechanism for foliar water uptake remains unclear. In this study, Tamarix ramosissima, a tree species widely distributed in desert regions, was investigated for gene expression patterns of AQPs and for sap flow velocity. Our results suggest that the foliar water uptake of T. ramosissima occurs in natural fields at night when the humidity is over a threshold of 85 %. The diurnal gene expression pattern of AQPs suggests that most AQP gene expressions display a circadian rhythm, and this could affect both photosynthesis and transpiration. At night, the PIP2-1 gene is also upregulated with increased relative air humidity. This gene expression pattern may allow desert plants to regulate foliar water uptake to adapt to extreme drought. This study suggests a molecular basis of foliar water uptake in desert plants. Published by Oxford University Press on behalf of the Annals of Botany Company.

  18. Out of the Desert: My Journey from Nomadic Bedouin to the Heart of Global Oil

    KAUST Repository

    Al-Naimi, Ali Ibrahim

    2017-01-01

    Arabian deserts. From his first job as a shepherd boy to his appointment to one of the most powerful political and economic jobs in the world, Out of the Desert charts Al-Naimi's extraordinary rise to power.

  19. Water quality and hydrology of the Lac Vieux Desert watershed, Gogebic County, Michigan, and Vilas County, Wisconsin, 2002-04

    Science.gov (United States)

    Weaver, T.L.; Neff, B.P.; Ellis, J.M.

    2005-01-01

    Lac Vieux Desert is a prominent 6.6 square-mile lake that straddles the Michigan-Wisconsin border and forms the headwaters of the Wisconsin River. For generations, the Lac Vieux Desert Band of Lake Superior Chippewa Indians have used Lac Vieux Desert and the surrounding area for growing and harvesting wild rice, and hunting and fishing. The Lac Vieux Desert Band is concerned about the impact of lake-stage regulation on hydrology and ecology, and the impact on water quality of development along and near the shore, and recreational watercraft use and sport fishing. In 2005, the U.S. Geological Survey completed a water-resources investigation of the Lac Vieux Desert watershed in cooperation with the Lac Vieux Desert Band of Lake Superior Chippewa Indians.Water quality of Lac Vieux Desert is typical of many lakes in the northern United States. Trophic State Index calculations classify Lac Vieux Desert as a highly productive eutrophic lake. The pH of water in Lac Vieux Desert ranged from 6.5 to 9.5, and specific conductance ranged from 62 to 114 µs/cm. Chloride concentration was less than 1.5 mg/L, indicating little effect from septic-tank or road-salt input. Results indicate that the water can be classified as soft, with hardness concentrations reported as calcium carbonate ranging from 29 to 49 mg/L. Concentrations of calcium, magnesium, chloride, and other dissolved solids ranged from 47 to 77 mg/L. Alkalinity of Lac Vieux Desert ranged from 27 to 38 mg/L.Pervasive aquatic blooms, including a bloom noted during the September 2003 sampling, are apparently common in late summer. Biological productivity at Lac Vieux Desert does not appear to have changed appreciably between 1973 and 2004. In the current study, total phosphorus concentrations ranged from 0.01 to 0.064 mg/L and dissolved nitrite plus nitrate nitrogen concentrations ranged from at, or below detection limit to 0.052 mg/L. Overabundance of nutrients in Lac Vieux Desert, particularly nitrogen and phosphorus

  20. Biotechnological Applications Derived from Microorganisms of the Atacama Desert

    Directory of Open Access Journals (Sweden)

    Armando Azua-Bustos

    2014-01-01

    Full Text Available The Atacama Desert in Chile is well known for being the driest and oldest desert on Earth. For these same reasons, it is also considered a good analog model of the planet Mars. Only a few decades ago, it was thought that this was a sterile place, but in the past years fascinating adaptations have been reported in the members of the three domains of life: low water availability, high UV radiation, high salinity, and other environmental stresses. However, the biotechnological applications derived from the basic understanding and characterization of these species, with the notable exception of copper bioleaching, are still in its infancy, thus offering an immense potential for future development.

  1. Food Swamps Predict Obesity Rates Better Than Food Deserts in the United States.

    Science.gov (United States)

    Cooksey-Stowers, Kristen; Schwartz, Marlene B; Brownell, Kelly D

    2017-11-14

    This paper investigates the effect of food environments, characterized as food swamps, on adult obesity rates. Food swamps have been described as areas with a high-density of establishments selling high-calorie fast food and junk food, relative to healthier food options. This study examines multiple ways of categorizing food environments as food swamps and food deserts, including alternate versions of the Retail Food Environment Index. We merged food outlet, sociodemographic and obesity data from the United States Department of Agriculture (USDA) Food Environment Atlas, the American Community Survey, and a commercial street reference dataset. We employed an instrumental variables (IV) strategy to correct for the endogeneity of food environments (i.e., that individuals self-select into neighborhoods and may consider food availability in their decision). Our results suggest that the presence of a food swamp is a stronger predictor of obesity rates than the absence of full-service grocery stores. We found, even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates. All three food swamp measures indicated the same positive association, but reflected different magnitudes of the food swamp effect on rates of adult obesity ( p values ranged from 0.00 to 0.16). Our adjustment for reverse causality, using an IV approach, revealed a stronger effect of food swamps than would have been obtained by naïve ordinary least squares (OLS) estimates. The food swamp effect was stronger in counties with greater income inequality ( p food outlets and incentivizing healthy food retailers to locate in underserved neighborhoods warrant consideration as strategies to increase health equity.

  2. Temporal dynamics of hot desert microbial communities reveal structural and functional responses to water input.

    Science.gov (United States)

    Armstrong, Alacia; Valverde, Angel; Ramond, Jean-Baptiste; Makhalanyane, Thulani P; Jansson, Janet K; Hopkins, David W; Aspray, Thomas J; Seely, Mary; Trindade, Marla I; Cowan, Don A

    2016-09-29

    The temporal dynamics of desert soil microbial communities are poorly understood. Given the implications for ecosystem functioning under a global change scenario, a better understanding of desert microbial community stability is crucial. Here, we sampled soils in the central Namib Desert on sixteen different occasions over a one-year period. Using Illumina-based amplicon sequencing of the 16S rRNA gene, we found that α-diversity (richness) was more variable at a given sampling date (spatial variability) than over the course of one year (temporal variability). Community composition remained essentially unchanged across the first 10 months, indicating that spatial sampling might be more important than temporal sampling when assessing β-diversity patterns in desert soils. However, a major shift in microbial community composition was found following a single precipitation event. This shift in composition was associated with a rapid increase in CO 2 respiration and productivity, supporting the view that desert soil microbial communities respond rapidly to re-wetting and that this response may be the result of both taxon-specific selection and changes in the availability or accessibility of organic substrates. Recovery to quasi pre-disturbance community composition was achieved within one month after rainfall.

  3. Temporal dynamics of hot desert microbial communities reveal structural and functional responses to water input

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, Alacia; Valverde, Angel; Ramond, Jean-Baptiste; Makhalanyane, Thulani P.; Jansson, Janet K.; Hopkins, David W.; Aspray, Thomas J.; Seely, Mary; Trindade, Marla I.; Cowan, Don A.

    2016-09-29

    The temporal dynamics of desert soil microbial communities are poorly understood. Given the implications for ecosystem functioning under a global change scenario, a better understanding of desert microbial community stability is crucial. Here, we sampled soils in the central Namib Desert on sixteen different occasions over a one-year period. Using Illumina-based amplicon sequencing of the 16S rRNA gene, we found that α-diversity (richness) was more variable at a given sampling date (spatial variability) than over the course of one year (temporal variability). Community composition remained essentially unchanged across the first 10 months, indicating that spatial sampling might be more important than temporal sampling when assessing β-diversity patterns in desert soils. However, a major shift in microbial community composition was found following a single precipitation event. This shift in composition was associated with a rapid increase in CO2 respiration and productivity, supporting the view that desert soil microbial communities respond rapidly to re-wetting and that this response may be the result of both taxon-specific selection and changes in the availability or accessibility of organic substrates. Recovery to quasi pre-disturbance community composition was achieved within one month after rainfall.

  4. Study of the microwave emissivity characteristics over Gobi Desert

    International Nuclear Information System (INIS)

    Yubao, Qiu; Lijuan, Shi; Wenbo, Wu

    2014-01-01

    The microwave emissivity represents the capacity of the thermal radiation of the surface, and it is the significant parameter for understanding the geophysical processes such as surface energy budget and surface radiation. Different land covers have different emissivity properties, and the Gobi Desert in Central Asia seriously impact the sandstorms occur and develop in China, because of its special geographical environment and surface soil characteristics. In this study half-month averaged microwave emissivity from March 2003 to February 2004 over the Gobi Desert has been estimated. Emissivities in this area at different frequencies, polarization and their seasonal variations are discussed respectively. The results showed that emissivity polarization difference decrease as the frequency increases, and the polarization difference is large (0.03–0.127). The H polarization emissivity increases with increasing frequency, but the V-polarized microwave emissivity is reduced with increasing frequency because of the body scattering. In winter, emissivity decreases sharply in snow covered area, especially for higher frequencies (such as 89GHz). In addition, we compared emissivity with MODIS NDVI data at the same time in the Gobi Desert, and the results indicate that NDVI derived the good negative correlation with microwave emissivity polarization difference at 37GHz

  5. The Great Kanto earthquake and F. Scott Fitzgerald

    Science.gov (United States)

    Kawakatsu, Hitoshi; Bina, Craig R.

    How many recall the following striking sentence from The Great Gatsby by F. Scott Fitzgerald, which appears on the second page of the novel, where Fitzgerald first introduces Gatsby? “If personality is an unbroken series of successful gestures, then there was something gorgeous about him, some heightened sensitivity to the promises of life, as if he were related to one of those intricate machines that register earthquakes ten thousand miles away.”This line may have failed to focus our attention when we first read the book in our younger days. Now, however, as a Japanese seismologist and an American geophysicist (and student of Japanese culture), we would be greatly remiss for failing to take greater note of this statement. Indeed, as The Great Gatsby was published in 1925, it occurred to us that the earthquake Fitzgerald might have been thinking of was the Great Kanto earthquake, which occurred on September 1, 1923 and devastated the Tokyo metropolitan area.

  6. Biological Communities in Desert Varnish and Potential Implications for Varnish Formation Mechanisms

    Science.gov (United States)

    Lang-Yona, Naama; Maier, Stefanie; Macholdt, Dorothea; Rodriguez-Caballero, Emilio; Müller-Germann, Isabell; Yordanova, Petya; Jochum, Klaus-Peter; Andreae, Meinrat O.; Pöschl, Ulrich; Weber, Bettina; Fröhlich-Nowoisky, Janine

    2017-04-01

    Desert varnishes are thin, orange to black coatings found on rocks in arid and semi-arid environments on Earth. The formation mechanisms of rock varnish are still under debate and the involvement of microorganisms in this process remains unclear. In this work we aimed to identify the microbial community occurring in rock varnish to potentially gain insights into the varnish formation mechanism. For this purpose, rocks coated with desert varnish were collected from the Anza-Borrego Desert, California, USA, as well as soils from underneath the rocks. DNA from both varnish coatings and soil samples was extracted and subsequently used for metagenomic analysis, as well as for q-PCR analyses for specific species quantification. The element composition of the varnish coatings was analyzed and compared to the soil samples. Rock varnish shows similar depleted elements, compared to soil, but Mn and Pb are 50-60 times enriched compared to the soil samples, and about 100 times enriched compared to the upper continental crust. Our genomic analyses suggest unique populations and different protein functional groups occurring in the varnish compared to soil samples. We discuss these differences and try to shed light on the mechanism of Mn oxyhydroxide production in desert varnish formation.

  7. Gravity, magnetic, and physical property data in the Smoke Creek Desert area, northwest Nevada

    Science.gov (United States)

    Tilden, Janet E.; Ponce, David A.; Glen, Jonathan M.G.; Chuchel, Bruce A.; Tushman, Kira; Duvall, Alison

    2006-01-01

    The Smoke Creek Desert, located approximately 100 km (60 mi) north of Reno near the California-Nevada border, is a large basin situated along the northernmost parts of the Walker Lane Belt (Stewart, 1988), a physiographic province defined by northwest-striking topographic features and strike-slip faulting. Because geologic framework studies play an important role in understanding the hydrology of the Smoke Creek Desert, a geologic and geophysical effort was begun to help determine basin geometry, infer structural features, and estimate depth to Pre-Cenozoic rocks, or basement. In May and June of 2004, and June of 2005, the U.S. Geological Survey (USGS) collected 587 new gravity stations, more than 160 line-kilometers (100 line-miles) of truck-towed magnetometer data, and 111 rock property samples in the Smoke Creek Desert and vicinity in northwest Nevada, as part of an effort to characterize its hydrogeologic framework. In the Smoke Creek Desert area, gravity highs occur over rocks of the Skedaddle Mountains, Fox Range, Granite Range, and over portions of Tertiary volcanic rocks in the Buffalo Hills. These gravity highs likely reflect basement rocks, either exposed at the surface or buried at shallow depths. The southern Smoke Creek Desert corresponds to a 25-mGal isostatic gravity low, which corresponds with a basin depth of approximately 2 km. Magnetic highs are likely due to granitic, andesitic, and metavolcanic rocks, whereas magnetic lows are probably associated with less magnetic gneiss and metasedimentary rocks in the region. Three distinctive patterns of magnetic anomalies occur throughout the Smoke Creek Desert and Squaw Creek Valley, likely reflecting three different geological and structural settings.

  8. Female offspring desertion and male-only care increase with natural and experimental increase in food abundance

    OpenAIRE

    Eldegard, Katrine; Sonerud, Geir A.

    2009-01-01

    In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a...

  9. 77 FR 11990 - Revisions to the California State Implementation Plan, Mojave Desert Air Quality Management...

    Science.gov (United States)

    2012-02-28

    ... the California State Implementation Plan, Mojave Desert Air Quality Management District and Yolo-Solano Air Quality Management District AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is proposing to approve revisions to the Mojave Desert Air Quality Management...

  10. Abiotic drivers of Chihuahuan Desert plant communities

    Science.gov (United States)

    Laura Marie Ladwig

    2014-01-01

    Within grasslands, precipitation, fire, nitrogen (N) addition, and extreme temperatures influence community composition and ecosystem function. The differential influences of these abiotic factors on Chihuahuan Desert grassland communities was examined within the Sevilleta National Wildlife Refuge, located in central New Mexico, U.S.A. Although fire is a natural...

  11. Regional Landscape System Protection in the Urbanising Desert Southwest: Lessons from the Phoenix Metropolitan Region, USA

    Directory of Open Access Journals (Sweden)

    Laura Musacchio

    2004-06-01

    Full Text Available Since the late nineteenth century, landscape protection in the deserts of the Southwest, United States of America, like many places worldwide, has been driven by the conservation of landscape icons, such as unusual geological features in wilderness areas. Yet, in the past two decades, leading conservation scholars worldwide have called for a shift in this paradigm to one that emphasises landscape systems, which is based on holistic landscape ecology. The shift in emphas is to landscape systems opens new opportunities to protect desert landscape systems at the regional scale rather than just remnant patches at the local scale. In this paper, the authors present, for public consideration, a typology of the five major desert landscapes that can be used as the bas is for protecting regional landscape systems in the deserts of the Southwest. As a case study, several representative examples of recent regional open space plans from the Phoenix metropolitan area are analysed and compared with the typology in order to understand how successfully the projects have addressed protection of the regional landscape system in the Sonoran Desert.

  12. Anthropogenic water sources and the effects on Sonoran Desert small mammal communities

    OpenAIRE

    Aaron B. Switalski; Heather L. Bateman

    2017-01-01

    Anthropogenic water sources (AWS) are developed water sources used as a management tool for desert wildlife species. Studies documenting the effects of AWS are often focused on game species; whereas, the effects on non-target wildlife are less understood. We used live trapping techniques to investigate rodent abundance, biomass, and diversity metrics near AWS and paired control sites; we sampled vegetation to determine rodent-habitat associations in the Sauceda Mountains of the Sonoran Desert...

  13. Economic analysis of critical habitat designation for the desert tortoise (Mojave population)

    Science.gov (United States)

    Schamberger, Mel; MacGillvray, Timothy J.; Draper, Dirk D.

    1993-01-01

    The U.S. Fish and Wildlife Service emergency 1isted the Mojave population of the desert tortoise as endangered on August 4, 1989. The Mojave population formally was listed as threatened on April 2, 1990. The Endangered Species Act of 1973, as amended, requires that the economic benefits and costs and other relevant effects of critical habitat designation be considered. The Secretary of the Interior may exclude from designation areas where the costs of designation are greater than the benefits, unless the exclusion would result in extinction of the species. Desert tortoises are threatened by an accumulation of human-and disease-related mortality accompanied by habitat destruction, degradation, and fragmentation. Many desert tortoises are illegally collected for pets, food, and commercial trade. Others are accidentally struck and killed by vehicles on roads and highways or are killed by gunshot or vehicles traveling off-highway. Raven predation on hatchling desert tortoises has increased as raven populations in the desert have risen. An upper respiratory tract disease is suspected to be a major cause of mortality in the western Mojave Desert. This presumably incurable affliction presumably is thought to be spread through the release of infected tortoises into the desert. The Service has proposed designating critical habitat in nine counties within four states. The 12 critical habitat units encompass 6.4 million acres of land, more than 80% federally owned. This region is economically and demographically diverse. Most of the land is sparsely settled and characterized as a hot desert ecosystem. Major industries in the region include entertainment and lodging (primarily in Las Vegas), property development to accommodate the rapid population growth, and services. Millions of rural acres in the region are leased by the federal government for livestock grazing and used for mining. Overall economic benefits to the affected states derived from cattle and sheep grazing in the

  14. Physiological conjunction of allelochemicals and desert plants.

    Science.gov (United States)

    Yosef Friedjung, Avital; Choudhary, Sikander Pal; Dudai, Nativ; Rachmilevitch, Shimon

    2013-01-01

    Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds) were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

  15. Physiological conjunction of allelochemicals and desert plants.

    Directory of Open Access Journals (Sweden)

    Avital Yosef Friedjung

    Full Text Available Plants exchange signals with other physical and biological entities in their habitat, a form of communication termed allelopathy. The underlying principles of allelopathy and secondary-metabolite production are still poorly understood, especially in desert plants. The coordination and role of secondary metabolites were examined as a cause of allelopathy in plants thriving under arid and semiarid soil conditions. Desert plant species, Origanum dayi, Artemisia sieberi and Artemisia judaica from two different sources (cultivar cuttings and wild seeds were studied in their natural habitats. Growth rate, relative water content, osmotic potential, photochemical efficiency, volatile composition and vital factors of allelopathy were analyzed at regular intervals along four seasons with winter showing optimum soil water content and summer showing water deficit conditions. A comprehensive analysis of the volatile composition of the leaves, ambient air and soil in the biological niche of the plants under study was carried out to determine the effects of soil water conditions and sample plants on the surrounding flora. Significant morpho-physiological changes were observed across the seasons and along different soil water content. Metabolic analysis showed that water deficit was the key for driving selective metabolomic shifts. A. judaica showed the least metabolic shifts, while A. sieberi showed the highest shifts. All the species exhibited high allelopathic effects; A. judaica displayed relatively higher growth-inhibition effects, while O. dayi showed comparatively higher germination-inhibition effects in germination assays. The current study may help in understanding plant behavior, mechanisms underlying secondary-metabolite production in water deficit conditions and metabolite-physiological interrelationship with allelopathy in desert plants, and can help cull economic benefits from the produced volatiles.

  16. Transitory microbial habitat in the hyperarid Atacama Desert

    Science.gov (United States)

    Schulze-Makuch, Dirk; Wagner, Dirk; Kounaves, Samuel P.; Mangelsdorf, Kai; Devine, Kevin G.; de Vera, Jean-Pierre; Schmitt-Kopplin, Philippe; Grossart, Hans-Peter; Parro, Victor; Kaupenjohann, Martin; Galy, Albert; Schneider, Beate; Airo, Alessandro; Frösler, Jan; Davila, Alfonso F.; Arens, Felix L.; Cáceres, Luis; Solís Cornejo, Francisco; Carrizo, Daniel; Dartnell, Lewis; DiRuggiero, Jocelyne; Flury, Markus; Ganzert, Lars; Gessner, Mark O.; Grathwohl, Peter; Guan, Lisa; Heinz, Jacob; Hess, Matthias; Keppler, Frank; Maus, Deborah; McKay, Christopher P.; Meckenstock, Rainer U.; Montgomery, Wren; Oberlin, Elizabeth A.; Probst, Alexander J.; Sáenz, Johan S.; Sattler, Tobias; Schirmack, Janosch; Sephton, Mark A.; Schloter, Michael; Uhl, Jenny; Valenzuela, Bernardita; Vestergaard, Gisle; Wörmer, Lars; Zamorano, Pedro

    2018-03-01

    Traces of life are nearly ubiquitous on Earth. However, a central unresolved question is whether these traces always indicate an active microbial community or whether, in extreme environments, such as hyperarid deserts, they instead reflect just dormant or dead cells. Although microbial biomass and diversity decrease with increasing aridity in the Atacama Desert, we provide multiple lines of evidence for the presence of an at times metabolically active, microbial community in one of the driest places on Earth. We base this observation on four major lines of evidence: (i) a physico-chemical characterization of the soil habitability after an exceptional rain event, (ii) identified biomolecules indicative of potentially active cells [e.g., presence of ATP, phospholipid fatty acids (PLFAs), metabolites, and enzymatic activity], (iii) measurements of in situ replication rates of genomes of uncultivated bacteria reconstructed from selected samples, and (iv) microbial community patterns specific to soil parameters and depths. We infer that the microbial populations have undergone selection and adaptation in response to their specific soil microenvironment and in particular to the degree of aridity. Collectively, our results highlight that even the hyperarid Atacama Desert can provide a habitable environment for microorganisms that allows them to become metabolically active following an episodic increase in moisture and that once it decreases, so does the activity of the microbiota. These results have implications for the prospect of life on other planets such as Mars, which has transitioned from an earlier wetter environment to today’s extreme hyperaridity.

  17. Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors

    Science.gov (United States)

    Angal, Amit; Chander, Gyanesh; Xiong, Xiaoxiong; Choi, Tae-young; Wu, Aisheng

    2011-01-01

    To provide highly accurate quantitative measurements of the Earth's surface, a comprehensive calibration and validation of the satellite sensors is required. The NASA Moderate Resolution Imaging Spectroradiometer (MODIS) Characterization Support Team, in collaboration with United States Geological Survey, Earth Resources Observation and Science Center, has previously demonstrated the use of African desert sites to monitor the long-term calibration stability of Terra MODIS and Landsat 7 (L7) Enhanced Thematic Mapper plus (ETM+). The current study focuses on evaluating the suitability of the Sonoran Desert test site for post-launch long-term radiometric calibration as well as cross-calibration purposes. Due to the lack of historical and on-going in situ ground measurements, the Sonoran Desert is not usually used for absolute calibration. An in-depth evaluation (spatial, temporal, and spectral stability) of this site using well calibrated L7 ETM+ measurements and local climatology data has been performed. The Sonoran Desert site produced spatial variability of about 3 to 5% in the reflective solar regions, and the temporal variations of the site after correction for view-geometry impacts were generally around 3%. The results demonstrate that, barring the impacts due to occasional precipitation, the Sonoran Desert site can be effectively used for cross-calibration and long-term stability monitoring of satellite sensors, thus, providing a good test site in the western hemisphere.

  18. Climatic variation and tortoise survival: has a desert species met its match?

    Science.gov (United States)

    Lovich, Jeffrey E.; Yackulic, Charles B.; Freilich, Jerry; Agha, Mickey; Austin, Meaghan; Meyer, Katherine P.; Arundel, Terence R.; Hansen, Jered; Vamstad, Michael S.; Root, Stephanie A.

    2014-01-01

    While demographic changes in short-lived species may be observed relatively quickly in response to climate changes, measuring population responses of long-lived species requires long-term studies that are not always available. We analyzed data from a population of threatened Agassiz’s desert tortoises (Gopherus agassizii) at a 2.59 km2 study plot in the Sonoran Desert ecosystem of Joshua Tree National Park, California, USA from 1978 to 2012 to examine variation in apparent survival and demography in this long-lived species. Transect-based, mark-recapture surveys were conducted in 10 of those years to locate living and dead tortoises. Previous modeling suggested that this area would become unsuitable as tortoise habitat under a warming and drying climate scenario. Estimated adult population size declined greatly from 1996 to 2012. The population appeared to have high apparent survival from 1978 to 1996 but apparent survival decreased from 1997 to 2002, concurrent with persistent drought. The best model relating apparent survivorship of tortoises ≥18 cm over time was based on a three year moving average of estimated winter precipitation. The postures and positions of a majority of dead tortoises found in 2012 were consistent with death by dehydration and starvation. Some live and many dead tortoises found in 2012 showed signs of predation or scavenging by mammalian carnivores. Coyote (Canis latrans) scats and other evidence from the site confirmed their role as tortoise predators and scavengers. Predation rates may be exacerbated by drought if carnivores switch from preferred mammalian prey to tortoises during dry years. Climate modeling suggests that the region will be subjected to even longer duration droughts in the future and that the plot may become unsuitable for continued tortoise survival. Our results showing wide fluctuations in apparent survival and decreasing tortoise density over time may be early signals of that possible outcome.

  19. Electricity from the desert; Strom aus der Wueste

    Energy Technology Data Exchange (ETDEWEB)

    Schwarzburger, Heiko; Ullrich, Sven

    2013-06-15

    The North African sun seems ideal for photovoltaic use. However, photovoltaic modules must withstand extreme loads in the desert. [German] Die Sonne Nordafrikas scheint ideal fuer die Photovoltaik-Nutzung. Jedoch muessen Photovoltaik-Module in der Wueste extremen Belastungen standhalten.

  20. Strategic sustainable development of groundwater in Thar desert of Pakistan

    International Nuclear Information System (INIS)

    Zaigham, N.A.

    2002-01-01

    Thar Desert forms the extreme southeastern part of Pakistan, covering about 50,000 km/sup 2/ area. It is one of the densely populated deserts of the world. Population of Thar is living primarily on limited agricultural products and by raising goats, sheep, cattle, and camels. The region is characterized by parallel chains of the NE-SW trending parabolic stable sanddunes having desertic varieties of vegetation, generally on windward sides, up to the crests. Interdunal areas are favourable for agricultural activities, where crops are mainly dependent on rainwater. Average rainfall is significant but inconsistent, due to recurrent drought-cycles causing inverse impact on food-production and socio-economic development. In spite of extensive groundwater- exploration projects, accomplished by a number of organizations, the water-crisis of the region could not be controlled, most probably due to lack of systematic exploration and development of deep groundwater potential. Management of the available water- resources is also not adequate, even to sustain a short period of drought-cycle. On recurrence of a drought-cycle, a significant section of the population is compelled to migrate towards other parts of the Sindh province, which affects their socio-economic stability. An integrated research study, based on geo-electric scanning, drilling and seismic-data analyses, has been carried out to delineate subsurface hydro-geological conditions beneath the Thar Desert. Regional gradient maps of surface elevation, top of subsurface Oxidized Zone, top of coal-bearing formation(s) and the deeply buried basement have been prepared, covering almost the whole of That Desert. These gradient maps, analyzed in conjunction with the annual rainfall data, reveal the existence of encouraging subsurface hydrogeological conditions, associated with the sedimentary sequences and the basement. From the results of the study, it is observed that perch water aquifers, commonly being utilized

  1. Integrating Army Aviation into the Combined Arms Team: Operational Art in Desert Shield and Desert Storm

    Science.gov (United States)

    2017-05-25

    King of Saudi Arabia. The conversation took place prior to an Organization of the Petroleum Exporting Countries (OPEC) meeting of Arab Gulf members...Blumberg and Christopher C. French, eds., The Persian Gulf War: Views from the Social and Behavioral Sciences (Lanham, MD: University Press of America...1994), 17. 72 Blumberg and French, The Persian Gulf War, 29. 20 building up forces in northeast Saudi Arabia during Operation Desert Shield, in

  2. Controls on the variability of net infiltration to desert sandstone

    Science.gov (United States)

    Heilweil, Victor M.; McKinney, Tim S.; Zhdanov, Michael S.; Watt, Dennis E.

    2007-01-01

    As populations grow in arid climates and desert bedrock aquifers are increasingly targeted for future development, understanding and quantifying the spatial variability of net infiltration becomes critically important for accurately inventorying water resources and mapping contamination vulnerability. This paper presents a conceptual model of net infiltration to desert sandstone and then develops an empirical equation for its spatial quantification at the watershed scale using linear least squares inversion methods for evaluating controlling parameters (independent variables) based on estimated net infiltration rates (dependent variables). Net infiltration rates used for this regression analysis were calculated from environmental tracers in boreholes and more than 3000 linear meters of vadose zone excavations in an upland basin in southwestern Utah underlain by Navajo sandstone. Soil coarseness, distance to upgradient outcrop, and topographic slope were shown to be the primary physical parameters controlling the spatial variability of net infiltration. Although the method should be transferable to other desert sandstone settings for determining the relative spatial distribution of net infiltration, further study is needed to evaluate the effects of other potential parameters such as slope aspect, outcrop parameters, and climate on absolute net infiltration rates.

  3. Forecasting Climate-Induced Ecosystem Changes on Army Installations

    Science.gov (United States)

    2011-10-01

    for this area by 2050. To find the best current example of conditions estimated for 2080 one needs to travel to the east area in Georgia. The Hadley...anticipated future conditions for the installation. In general one must travel south, or down-slope, to find the anticipated future conditions today...Tableland []3301) Western Great Plains Badland []3405) North American Warm Desert Playa []J407) Inter-Mountain Basins Playa []3501) North Pacific

  4. DESERT ECOSYSTEMS: MAPPING, MONITORING & ASSESSMENT USING SATELLITE REMOTE SENSING

    Directory of Open Access Journals (Sweden)

    A. S. Arya

    2012-09-01

    Full Text Available Desert ecosystems are unique but fragile ecosystems , mostly vulnerable to a variety of degradational processes like water erosion, vegetal degradation, salinity, wind erosion , water logging etc. Some researchers consider desertification to be a process of change, while others view it as the end result of a process of change. There is an urgent need to arrest the process of desertification and combat land degradation. Under the auspices of the United Nations Convention to Combat Desertification (UNCCD, Space Applications Centre, Ahmedabad has undertaken the task of mapping, monitoring and assessment of desertification carrying out pilot project in hot and cold desert regions in drylands on 1:50,000 scale followed by systematic Desertification Status Mappaing (DSM of India on 1:500,000 scale.

  5. 76 FR 59682 - Desert Southwest Customer Service Region-Western Area Lower Colorado Balancing Authority-Rate...

    Science.gov (United States)

    2011-09-27

    ... DEPARTMENT OF ENERGY Western Area Power Administration Desert Southwest Customer Service Region... CONTACT: Mr. Jack Murray, Rates Manager, Desert Southwest Customer Service Region, Western Area Power... Customer Service Region Network Integration Transmission Service Rate Schedules PD-NTS3 and INT-NTS3 for P...

  6. Late Pleistocene paleohydrology near the boundary of the Sonoran and Chihuahuan Deserts, southeastern Arizona, USA

    Science.gov (United States)

    Pigati, Jeffery S.; Bright, Jordon E.; Shanahan, Timothy M.; Mahan, Shannon

    2009-01-01

    Ground-water discharge (GWD) deposits form in arid environments as water tables rise and approach or breach the ground surface during periods of enhanced effective precipitation. Where preserved, these deposits contain information on the timing and elevation of past ground-water fluctuations. Here we report on the investigation of a series of GWD deposits that are exposed in discontinuous outcrops along a ???150-km stretch of the San Pedro Valley in southeastern Arizona, near the boundary of the Sonoran and Chihuahuan Deserts. Chronologic, isotopic, geochemical, faunal assemblage (ostracodes and gastropods), and sedimentological evidence collectively suggest that the elevation of the regional water table in the valley rose in response to a change in climate ???50 ka ago and remained relatively high for the next ???35 ka before falling during the B??lling-Aller??d warm period, rebounding briefly during the Younger Dryas cold event, and falling again at the onset of the Holocene. The timing of these hydrologic changes coincides closely with variations in ??18O values of calcite from a nearby speleothem to the west and changes in lake levels at pluvial Lake Cochise to the east. Thus, in southeastern Arizona, the assumption that changes in climate are reflected in all aspects of the hydrologic cycle of a region simultaneously is validated. The timing of these changes also broadly coincides with variations in the GISP2 ??18O record, which supports the hypothesis that atmospheric teleconnections existed between the North Atlantic and the deserts of the American Southwest during the late Pleistocene.

  7. Thermal design of a modern, air-conditioned, single-floor, solar-powered desert house

    KAUST Repository

    Serag-Eldin, M. A.

    2011-12-01

    The paper presents a thermal analysis of a single-floor, solar-powered desert house. The house is air-conditioned and provides all modern comforts and facilities. Electrical power, which drives the entire energy system, is generated by roof-mounted photovoltaic modules. The modules are fixed on special cradles which fold at night to expose the roof to the night sky, thereby enhancing night-time cooling, which is substantial in the desert environment. A detailed dynamic heat transfer analysis is conducted for the building envelope, coupled with a solar radiation model. Application to a typical Middle-Eastern desert site reveals that indeed such a design is feasible with present-day technology; and should be even more attractive with future advances in technology. © 2011 Copyright Taylor and Francis Group, LLC.

  8. The Depiction of Native Americans in Recent (1991-2004) Secondary American History Textbooks: How Far Have We Come?

    Science.gov (United States)

    Sanchez, Tony R.

    2007-01-01

    This study examined 15 secondary American history textbooks to evaluate their accuracy in depicting Native Americans as a follow-up to studies by Costo and Henry (1970) and Loewen (1995). The criteria embodied an authenticity guideline based upon the Five Great Values with a rating scale between 1 (lowest) and 5 (highest). The results indicate…

  9. 75 FR 13805 - Aspen Group Resources Corp., Commercial Concepts, Inc., Desert Health Products, Inc., Equalnet...

    Science.gov (United States)

    2010-03-23

    ... Concepts, Inc., Desert Health Products, Inc., Equalnet Communications Corp., Geneva Steel Holdings Corp... securities of Commercial Concepts, Inc. because it has not filed any periodic reports since the period ended... accurate information concerning the securities of Desert Health Products, Inc. because it has not filed any...

  10. Bacterial diversity of surface sand samples from the Gobi and Taklamaken deserts.

    Science.gov (United States)

    An, Shu; Couteau, Cécile; Luo, Fan; Neveu, Julie; DuBow, Michael S

    2013-11-01

    Arid regions represent nearly 30 % of the Earth's terrestrial surface, but their microbial biodiversity is not yet well characterized. The surface sands of deserts, a subset of arid regions, are generally subjected to large temperature fluctuations plus high UV light exposure and are low in organic matter. We examined surface sand samples from the Taklamaken (China, three samples) and Gobi (Mongolia, two samples) deserts, using pyrosequencing of PCR-amplified 16S V1/V2 rDNA sequences from total extracted DNA in order to gain an assessment of the bacterial population diversity. In total, 4,088 OTUs (using ≥97 % sequence similarity levels), with Chao1 estimates varying from 1,172 to 2,425 OTUs per sample, were discernable. These could be grouped into 102 families belonging to 15 phyla, with OTUs belonging to the Firmicutes, Proteobacteria, Bacteroidetes, and Actinobacteria phyla being the most abundant. The bacterial population composition was statistically different among the samples, though members from 30 genera were found to be common among the five samples. An increase in phylotype numbers with increasing C/N ratio was noted, suggesting a possible role in the bacterial richness of these desert sand environments. Our results imply an unexpectedly large bacterial diversity residing in the harsh environment of these two Asian deserts, worthy of further investigation.

  11. Impact of Precipitation Fluctuation on Desert-Grassland ANPP

    Directory of Open Access Journals (Sweden)

    Liangxu Liu

    2016-11-01

    Full Text Available Precipitation change has significantly influenced annual net primary productivity (ANPP at either annual or seasonal scales in desert steppes in arid and semi-arid regions. In order to reveal the process of precipitation driving ANPP at different time scales, responses of different ANPP levels to the inter-annual and intra-annual precipitation fluctuations were analyzed. ANPP was reversed by building a ground reflectance spectrum model, from 2000 to 2015, using the normalized differential vegetation index of the Moderate-Resolution Imaging Spectroradiometer (MODIS-NDVI data at 250 m × 250 m spatial resolution. Since the description of the differently expressing forms of precipitation are not sufficient in former studies in order to overcome the deficiency of former studies, in this study, intra-annual precipitation fluctuations were analyzed not only with precipitation of May–August, June–August, July–August, and August, respectively, which have direct influence on vegetation productivity within the year, but quantitative description, vector precipitation (R, concentration ratio (Cd, and concentration period (D, were also used to describe the overall characteristics of intra-annual precipitation fluctuations. The concentration ratio and the maximum precipitation period of the intra-annual precipitation were represented by using monthly precipitation. The results showed that: (1 in the period from 1971 to 2015, the maximum annual precipitation is 3.76 times that of the minimum in the Urat desert steppe; (2 vector precipitation is more significantly related to ANPP (r = 0.7724, p = 0.000 compared to meteorological annual precipitation and real annual precipitation influence; and (3 annual precipitation is almost concentrated in 5–8 months and monthly precipitation accumulation has significantly effected ANPP, especially in the period of June–August, since the vegetation composition in the study area was mainly sub-shrubs and perennial

  12. Fog deposition to the Atacama desert

    Science.gov (United States)

    Westbeld, A.; Klemm, O.; Griessbaum, F.; Sträter, E.; Larrain, H.; Osses, P.; Cereceda, P.

    2010-07-01

    In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water to a desert. We estimated the amount of water available for the ecosystem by deposition and determined the relevant processes driving fog deposition. This is especially important for the species Tillandsia landbecki living in coastal Atacama at the limit of plant existence with fog and dew being the only sources of liquid water. Between 31 July and 19 August, 2008, measurements were realized in a 31 ha large Tillandsia carpet at Cerro Guanaco, located 15 km south of Iquique, northern Chile. Several data quality assurance procedures were applied. For the values in compliance with the applied criteria, the mean total deposition per hour was determined (0.04 L per m2) for foggy periods. This number was applied to estimate the amount of water deposited during the measuring period, during the entire month of August 2008, and throughout a whole year. For August 2008, a frequency of fog of 16 %, as established during the measuring period, was assumed. The frequency for a whole year was estimated from the differences of the collected amount of water obtained with standard fog collectors installed at Cerro Guanaco in an earlier study. Calculations resulted in an amount of 2.5 L per m2 of deposited fog water for the measuring period. During the entire August, 4.4 L per m2 have likely been available, and for a whole year, a total of 25 L per m2 was estimated to have reached the surface. Inaccuracies could have been caused by the low amount of data applied, and by a possible underestimation of the deposition due to additional formation of radiation fog during the fog events. Three days were used for further analysis because

  13. Sediment grain-size characteristics and relevant correlations to the aeolian environment in China's eastern desert region.

    Science.gov (United States)

    Zhang, Chunlai; Shen, Yaping; Li, Qing; Jia, Wenru; Li, Jiao; Wang, Xuesong

    2018-06-15

    To identify characteristics of aeolian activity and the aeolian environment in China's eastern desert region, this study collected surface sediment samples from the main desert and sandy lands in this region: the Hobq Desert and the Mu Us, Otindag, Horqin, and Hulunbuir sandy lands. We analyzed the grain-size characteristics and their relationships to three key environmental indicators: drift potential, the dune mobility index, and vegetation cover. The main sediment components are fine to medium sands, with poor (Hulunbuir) to moderate (all other areas) sorting, of unimodal to bimodal distribution. This suggests that improved sorting is accomplished by the loss of both relatively coarser and finer grains. Since 2000, China's eastern desert region has generally experienced low wind energy environmental conditions, resulting in decreased dune activity. In the Hobq Desert, however, the dry climate and sparse vegetation, in conjunction with the most widely distributed mobile dune area in the eastern desert region, have led to frequent and intense aeolian activity, including wind erosion, sand transport, and deposition, resulting in conditions for good sediment sorting. In the Mu Us, Otindag, and Horqin sandy lands, mosaic distribution has resulted from wind erosion-dominated and deposition-dominated aeolian environments. In the Hulunbuir Sandy Land, high precipitation, low temperatures, and steppe vegetation have resulted in well-developed soils; however, strong winds and flat terrain have created an aeolian environment dominated by wind erosion. Copyright © 2018. Published by Elsevier B.V.

  14. Shrubland carbon sink depends upon winter water availability in the warm deserts of North America

    Science.gov (United States)

    Biederman, Joel A.; Scott, Russell L.; John A. Arnone,; Jasoni, Richard L.; Litvak, Marcy E.; Moreo, Michael T.; Papuga, Shirley A.; Ponce-Campos, Guillermo E.; Schreiner-McGraw, Adam P.; Vivoni, Enrique R.

    2018-01-01

    Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of the land CO2 sink. However, such model-based analyses are poorly constrained by measured CO2 exchange in open shrublands, which is the most common global land cover type, covering ∼14% of Earth’s surface. Here we evaluate how the amount and seasonal timing of water availability regulate CO2 exchange between shrublands and the atmosphere. We use eddy covariance data from six US sites across the three warm deserts of North America with observed ranges in annual precipitation of ∼100–400mm, annual temperatures of 13–18°C, and records of 2–8 years (33 site-years in total). The Chihuahuan, Sonoran and Mojave Deserts present gradients in both mean annual precipitation and its seasonal distribution between the wet-winter Mojave Desert and the wet-summer Chihuahuan Desert. We found that due to hydrologic losses during the wettest summers in the Sonoran and Chihuahuan Deserts, evapotranspiration (ET) was a better metric than precipitation of water available to drive dryland CO2 exchange. In contrast with recent synthesis studies across diverse dryland biomes, we found that NEP could not be directly predicted from ET due to wintertime decoupling of the relationship between ecosystem respiration (Reco) and gross ecosystem productivity (GEP). Ecosystem water use efficiency (WUE=GEP/ET) did not differ between winter and summer. Carbon use efficiency (CUE=NEP/GEP), however, was greater in winter because Reco returned a smaller fraction of carbon to the atmosphere (23% of GEP) than in summer (77%). Combining the water-carbon relations found here with historical precipitation since 1980, we estimate that lower average winter precipitation during the 21st century reduced the net carbon sink of the three deserts by an average of 6.8TgC yr1. Our results highlight that winter precipitation is critical to the annual carbon balance of these

  15. Effect of radiophosphorus on the haematology of Indian desert gerbil (Meriones hurrianae, Jerdon)

    International Nuclear Information System (INIS)

    Malhotra, N.

    1985-01-01

    The effect of 32 P (55.5 kBq/g body weight) has been studied on the hematology of the Indian desert gerbil (Meriones hurrianae) up to a maximum period of 28 d. The investigation reveals induction of leukocytopenia after a brief and transient leukocytosis. The changes in red blood cells, hemoglobin and hematocrit levels are not significant. The desert gerbil appears to be fairly radioresistant at this dose level. (author)

  16. Desert Rats 2010 Operations Tests: Insights from the Geology Crew Members

    Science.gov (United States)

    Bleacher, J. E.; Hurtado, J. M., Jr.; Young, K. E.; Rice, J.; Garry, W. B.; Eppler, D.

    2011-01-01

    Desert Research and Technology Studies (Desert RATS) is a multi-year series of tests of NASA hardware and operations deployed in the high desert of Arizona. Conducted annually since 1997, these activities exercise planetary surface hardware and operations in relatively harsh conditions where long-distance, multi-day roving is achievable. Such activities not only test vehicle subsystems, they also stress communications and operations systems and enable testing of science operations approaches that advance human and robotic surface exploration capabilities. Desert RATS 2010 tested two crewed rovers designed as first-generation prototypes of small pressurized vehicles, consistent with exploration architecture designs. Each rover provided the internal volume necessary for crewmembers to live and work for periods up to 14 days, as well as allowing for extravehicular activities (EVAs) through the use of rear-mounted suit ports. The 2010 test was designed to simulate geologic science traverses over a 14-day period through a volcanic field that is analogous to volcanic terrains observed throughout the Solar System. The test was conducted between 31 August and 13 September 2010. Two crewmembers lived in and operated each rover for a week with a "shift change" on day 7, resulting in a total of eight test subjects for the two-week period. Each crew consisted of an engineer/commander and an experienced field geologist. Three of the engineer/commanders were experienced astronauts with at least one Space Shuttle flight. The field geologists were drawn from the scientific community, based on funded and published field expertise.

  17. Application of Science-Based Restoration Planning to a Desert River System

    Science.gov (United States)

    Laub, Brian G.; Jimenez, Justin; Budy, Phaedra

    2015-06-01

    Persistence of many desert river species is threatened by a suite of impacts linked to water infrastructure projects that provide human water security where water is scarce. Many desert rivers have undergone regime shifts from spatially and temporally dynamic ecosystems to more stable systems dominated by homogenous physical habitat. Restoration of desert river systems could aid in biodiversity conservation, but poses formidable challenges due to multiple threats and the infeasibility of recovery to pre-development conditions. The challenges faced in restoring desert rivers can be addressed by incorporating scientific recommendations into restoration planning efforts at multiple stages, as demonstrated here through an example restoration project. In particular, use of a watershed-scale planning process can identify data gaps and irreversible constraints, which aid in developing achievable restoration goals and objectives. Site-prioritization focuses limited the resources for restoration on areas with the greatest potential to improve populations of target organisms. Investment in research to understand causes of degradation, coupled with adoption of a guiding vision is critical for identifying feasible restoration actions that can enhance river processes. Setting monitoring as a project goal, developing hypotheses for expected outcomes, and implementing restoration as an experimental design will facilitate adaptive management and learning from project implementation. Involvement of scientists and managers during all planning stages is critical for developing process-based restoration actions and an implementation plan to maximize learning. The planning process developed here provides a roadmap for use of scientific recommendations in future efforts to recover dynamic processes in imperiled riverine ecosystems.

  18. Application of science-based restoration planning to a desert river system

    Science.gov (United States)

    Laub, Brian G.; Jimenez, Justin; Budy, Phaedra

    2015-01-01

    Persistence of many desert river species is threatened by a suite of impacts linked to water infrastructure projects that provide human water security where water is scarce. Many desert rivers have undergone regime shifts from spatially and temporally dynamic ecosystems to more stable systems dominated by homogenous physical habitat. Restoration of desert river systems could aid in biodiversity conservation, but poses formidable challenges due to multiple threats and the infeasibility of recovery to pre-development conditions. The challenges faced in restoring desert rivers can be addressed by incorporating scientific recommendations into restoration planning efforts at multiple stages, as demonstrated here through an example restoration project. In particular, use of a watershed-scale planning process can identify data gaps and irreversible constraints, which aid in developing achievable restoration goals and objectives. Site-prioritization focuses limited the resources for restoration on areas with the greatest potential to improve populations of target organisms. Investment in research to understand causes of degradation, coupled with adoption of a guiding vision is critical for identifying feasible restoration actions that can enhance river processes. Setting monitoring as a project goal, developing hypotheses for expected outcomes, and implementing restoration as an experimental design will facilitate adaptive management and learning from project implementation. Involvement of scientists and managers during all planning stages is critical for developing process-based restoration actions and an implementation plan to maximize learning. The planning process developed here provides a roadmap for use of scientific recommendations in future efforts to recover dynamic processes in imperiled riverine ecosystems.

  19. Precipitation Dynamics and Feedback mechanisms of the Arabian Desert

    Science.gov (United States)

    Burger, Roelof; Kucera, Paul; Piketh, Stuart; Axisa, Duncan; Chapman, Michael; Krauss, Terry; Ghulam, Ayman

    2010-05-01

    The subtropical Arabian desert extends across the entire Peninsula. The Arabian desert finds itself in the downward branch of the Hadley cell with persistent subsidence. This stabilizes the atmosphere and lowers the relative humidity. The result is a strongly capped convective boundary layer and an extremely dry mid troposphere. Most of the area experience very little rainfall, generally below 100 mm per year, resulting in the largest uninterrupted sand desert in the world. However, local factors such as an unbroken 1000 km escarpment along the Red Sea, rocky mountains between 2000 and 3000 m, and gravel plains cut by wadis, causes micro climates with significant altered precipitation characteristics. Altitude oases with annual rainfall between 200 mm and 500 mm are found on the Asir mountains in the south west and over the Jebel Akdhar mountains on the Gulf coast of Oman. This region receives most of its rainfall in the Northern Hemisphere summer driven by a monsoon trough and the ITCZ. During summer, moist surface winds from the Red Sea converges with dry easterlies triggering convection along the Asir escarpment on a daily basis. Clear mornings grow into a layer of Altocumulus stratiformis cumulogenites by noon, which usually last until sunset. This cloud deck interacts with large severe convective cells which grow to the top of the troposphere by mid afternoon. The north experience a mediterranean climate with eastward propagating midlatitude cyclones causing wintertime rainfall. Characteristic cloud bands form over the northern interior. Vertically layered embedded convective cells that are not coupled with the surface propagate on north easterly tracks. This result in another oasis with annual rainfall exceeding 200 mm. Surface based convection causes isolated thunderstorms during spring and early summer, but cloud bases increase as the season progress until the evaporating downdraft causes dust storms. In-situ measurements, WRF model runs, radiosonde ascends

  20. Cyanobacterial composition and spatial distribution based on pyrosequencing data in the Gurbantunggut Desert, Northwestern China.

    Science.gov (United States)

    Zhang, Bingchang; Li, Renhui; Xiao, Peng; Su, Yangui; Zhang, Yuanming

    2016-03-01

    Cyanobacteria are the primary colonizers and form a dominant component of soil photosynthetic communities in biological soil crusts. They are crucial in improving soil environments, namely accumulating soil carbon and nitrogen. Many classical studies have examined cyanobacterial diversity in desert crusts, but relatively few comprehensive molecular surveys have been conducted. We used 454 pyrosequencing of 16S rRNA to investigate cyanobacterial composition and distribution on regional scales in the Gurbantunggut Desert. The relationship between cyanobacterial distribution and environmental factors was also explored. A total of 24,973 cyanobacteria partial 16S rRNA gene sequences were obtained, and 507OTUs were selected, as most OTUs had very few reads. Among these, 347 OTU sequences were of cyanobacteria origin, belonging to Oscillatoriales, Nostocales, Chroococcales, and uncultured cyanobacterium clone, respectively. Microcoleus vaginatus, Chroococcidiopsis spp. and M. steenstrupii were the dominant species in most areas of the Gurbantunggut Desert. Compared with other desert, the Gurbantunggut Desert differed in the prominence of Chroococcidiopsis spp. and lack of Pseudanabaenales. Species composition and abundance of cyanobacteria also showed distinct variations. Soil texture, precipitation, and nutrients and salt levels affected cyanobacterial distribution. Increased precipitation was helpful in improving cyanobacterial diversity. A higher content of coarse sand promoted the colonization and growth of Oscillatoriales and some phylotypes of Chroococcales. The fine-textured soil with higher nutrients and salts supported more varied populations of cyanobacteria, namely some heterocystous cyanobacteria. The results suggested that the Gurbantunggut Desert was rich in cyanobacteria and that precipitation was a primary regulating factor for cyanobacterial composition on a regional scale. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Iron Mineralogy and Speciation in Clay-Sized Fractions of Chinese Desert Sediments

    Science.gov (United States)

    Lu, Wanyi; Zhao, Wancang; Balsam, William; Lu, Huayu; Liu, Pan; Lu, Zunli; Ji, Junfeng

    2017-12-01

    Iron released from Asian desert dust may be an important source of bioavailable iron for the North Pacific Ocean and thereby may stimulate primary productivity. However, the Fe species of the fine dusts from this source region are poorly characterized. Here we investigate iron species and mineralogy in the clay-sized fractions (iron phases (ferrihydrite and lepidocrocite) and reducible iron oxides (dominated by goethite) are 0.81 wt % and 2.39 wt %, respectively, and Fe dissolved from phyllosilicates extracted by boiling HCl (dominated by chlorite) is 3.15 wt %. Dusts originating from deserts in northwestern China, particularly the Taklimakan desert, are relatively enriched in easily reducible Fe phases, probably due to abundant Fe contained in fresh weathering products resulting from the rapid erosion associated with active uplift of mountains to the west. Data about Fe speciation and mineralogy in Asian dust sources will be useful for improving the quantification of soluble Fe supplied to the oceans, especially in dust models.

  2. Physiological ecology of desert iguana (Dipsosaurus dorsalis) eggs: temperature and water relations

    Energy Technology Data Exchange (ETDEWEB)

    Muth, A.

    1980-12-01

    The soil environment imposes constraints on the timing of oviposition and the location of suitable sites for egg burrows of the desert iguana (Dipsosaurus dorsalis). The effects of temperature and water potential on the developmental period and hatching success of eggs were determined. Eggs hatch normally between 28/sup 0/ and 38/sup 0/C at environmental water potentials between -50 and -1500 kPa. Predictions were derived for the timing and placement of egg clutches based on soil water potential and temperature profiles measured in the field and on the results of laboratory incubation experiments. The results suggest that egg burrows should be located at depths >22 cm in washes or possibly in sparsely vegetated areas away from creosote bushes. The biogeography of desert iguanas within the United States is discussed in relation to soil environments and tolerances of eggs. The physical factors affecting incubation may limit the geographical range of desert iguanas.

  3. Where do food desert residents buy most of their junk food? Supermarkets.

    Science.gov (United States)

    Vaughan, Christine A; Cohen, Deborah A; Ghosh-Dastidar, Madhumita; Hunter, Gerald P; Dubowitz, Tamara

    2017-10-01

    To examine where residents in an area with limited access to healthy foods (an urban food desert) purchased healthier and less healthy foods. Food shopping receipts were collected over a one-week period in 2013. These were analysed to describe where residents shopped for food and what types of food they bought. Two low-income, predominantly African-American neighbourhoods with limited access to healthy foods in Pittsburgh, PA, USA. Two hundred and ninety-three households in which the primary food shoppers were predominantly female (77·8 %) and non-Hispanic black (91·1 %) adults. Full-service supermarkets were by far the most common food retail outlet from which food receipts were returned and accounted for a much larger proportion (57·4 %) of food and beverage expenditures, both healthy and unhealthy, than other food retail outlets. Although patronized less frequently, convenience stores were notable purveyors of unhealthy foods. Findings highlight the need to implement policies that can help to decrease unhealthy food purchases in full-service supermarkets and convenience stores and increase healthy food purchases in convenience stores.

  4. Nelson's big horn sheep (Ovis canadensis nelsoni) trample Agassiz's desert tortoise (Gopherus agassizii) burrow at a California wind energy facility

    Science.gov (United States)

    Agha, Mickey; Delaney, David F.; Lovich, Jeffrey E.; Briggs, Jessica; Austin, Meaghan; Price, Steven J.

    2015-01-01

    Research on interactions between Agassiz's desert tortoises (Gopherus agassizii) and ungulates has focused exclusively on the effects of livestock grazing on tortoises and their habitat (Oldemeyer, 1994). For example, during a 1980 study in San Bernardino County, California, 164 desert tortoise burrows were assessed for vulnerability to trampling by domestic sheep (Ovis aries). Herds of grazing sheep damaged 10% and destroyed 4% of the burrows (Nicholson and Humphreys 1981). In addition, a juvenile desert tortoise was trapped and an adult male was blocked from entering a burrow due to trampling by domestic sheep. Another study found that domestic cattle (Bos taurus) trampled active desert tortoise burrows and vegetation surrounding burrows (Avery and Neibergs 1997). Trampling also has negative impacts on diversity of vegetation and intershrub soil crusts in the desert southwest (Webb and Stielstra 1979). Trampling of important food plants and overgrazing has the potential to create competition between desert tortoises and domestic livestock (Berry 1978; Coombs 1979; Webb and Stielstra 1979).

  5. Food Swamps Predict Obesity Rates Better Than Food Deserts in the United States

    Directory of Open Access Journals (Sweden)

    Kristen Cooksey-Stowers

    2017-11-01

    Full Text Available This paper investigates the effect of food environments, characterized as food swamps, on adult obesity rates. Food swamps have been described as areas with a high-density of establishments selling high-calorie fast food and junk food, relative to healthier food options. This study examines multiple ways of categorizing food environments as food swamps and food deserts, including alternate versions of the Retail Food Environment Index. We merged food outlet, sociodemographic and obesity data from the United States Department of Agriculture (USDA Food Environment Atlas, the American Community Survey, and a commercial street reference dataset. We employed an instrumental variables (IV strategy to correct for the endogeneity of food environments (i.e., that individuals self-select into neighborhoods and may consider food availability in their decision. Our results suggest that the presence of a food swamp is a stronger predictor of obesity rates than the absence of full-service grocery stores. We found, even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates. All three food swamp measures indicated the same positive association, but reflected different magnitudes of the food swamp effect on rates of adult obesity (p values ranged from 0.00 to 0.16. Our adjustment for reverse causality, using an IV approach, revealed a stronger effect of food swamps than would have been obtained by naïve ordinary least squares (OLS estimates. The food swamp effect was stronger in counties with greater income inequality (p < 0.05 and where residents are less mobile (p < 0.01. Based on these findings, local government policies such as zoning laws simultaneously restricting access to unhealthy food outlets and incentivizing healthy food retailers to locate in underserved neighborhoods warrant consideration as strategies to increase health equity.

  6. Food Swamps Predict Obesity Rates Better Than Food Deserts in the United States

    Science.gov (United States)

    Cooksey-Stowers, Kristen; Schwartz, Marlene B.; Brownell, Kelly D.

    2017-01-01

    This paper investigates the effect of food environments, characterized as food swamps, on adult obesity rates. Food swamps have been described as areas with a high-density of establishments selling high-calorie fast food and junk food, relative to healthier food options. This study examines multiple ways of categorizing food environments as food swamps and food deserts, including alternate versions of the Retail Food Environment Index. We merged food outlet, sociodemographic and obesity data from the United States Department of Agriculture (USDA) Food Environment Atlas, the American Community Survey, and a commercial street reference dataset. We employed an instrumental variables (IV) strategy to correct for the endogeneity of food environments (i.e., that individuals self-select into neighborhoods and may consider food availability in their decision). Our results suggest that the presence of a food swamp is a stronger predictor of obesity rates than the absence of full-service grocery stores. We found, even after controlling for food desert effects, food swamps have a positive, statistically significant effect on adult obesity rates. All three food swamp measures indicated the same positive association, but reflected different magnitudes of the food swamp effect on rates of adult obesity (p values ranged from 0.00 to 0.16). Our adjustment for reverse causality, using an IV approach, revealed a stronger effect of food swamps than would have been obtained by naïve ordinary least squares (OLS) estimates. The food swamp effect was stronger in counties with greater income inequality (p < 0.05) and where residents are less mobile (p < 0.01). Based on these findings, local government policies such as zoning laws simultaneously restricting access to unhealthy food outlets and incentivizing healthy food retailers to locate in underserved neighborhoods warrant consideration as strategies to increase health equity. PMID:29135909

  7. HERBERT HOOVER, GREAT BRITAIN, AND THE RUBBER CRISIS, 1923-1926

    Directory of Open Access Journals (Sweden)

    Silvano A. Wueschner

    2000-01-01

    Full Text Available This paper examines the controversy arising out of Great Britain’s decision to implement the Stevenson plan. It examines, in particular, the role played by Herbert Hoover, both behind the scenes and in an effort to affect the repeal of the Stevenson scheme and at the same time to encourage and support the development of new sources of rubber under the control of American producers. During the period 1920-1922 rubber producing countries were confronted by the specter of overproduction. The existence of even a short term oversupply coupled with the business slump, a reaction from the war, led to a decline in the price of rubber. British producers succeeded in inducing the British Colonial authorities to support a scheme whereby rubber exports would be regulated in order to bring about an increase in the price of rubber. This plan, developed by the Stevenson Committee, called for a small minimum tax on all exports. Moreover, it soughtto limit production by establishing a quota based on the actual production of rubber during the 1919-1920 growing season. A progressive tax was applied to exports beyond standard production. American reaction to the scheme was varied. Secretary of Commerce Hoover, while publicly stating that the price of rubber had been low and was supportive of efforts to regulate production, behind the scenes showed a great deal of concern about the actions of the British government in regulating a commodity of which the United States was the single largest consumer. He was also linked, by some, to the idea that Great Britain sought to pay its war debt to the United States through the application of this tax. Much was made in American newspapers and the British press about Hoover’s criticism of British rubber restrictions. He was not opposed to regulating the supply of rubber, but only to the involvement of a government in the process, especially when it affected American producers and consumers. In response he proposed a scheme

  8. Spatial patterns and temporal trends in mercury concentrations, precipitation depths, and mercury wet deposition in the North American Great Lakes region, 2002–2008

    International Nuclear Information System (INIS)

    Risch, Martin R.; Gay, David A.; Fowler, Kathleen K.; Keeler, Gerard J.; Backus, Sean M.; Blanchard, Pierrette; Barres, James A.; Dvonch, J. Timothy

    2012-01-01

    Annual and weekly mercury (Hg) concentrations, precipitation depths, and Hg wet deposition in the Great Lakes region were analyzed by using data from 5 monitoring networks in the USA and Canada for a 2002–2008 study period. High-resolution maps of calculated annual data, 7-year mean data, and net interannual change for the study period were prepared to assess spatial patterns. Areas with 7-year mean annual Hg concentrations higher than the 12 ng per liter water-quality criterion were mapped in 4 states. Temporal trends in measured weekly data were determined statistically. Monitoring sites with significant 7-year trends in weekly Hg wet deposition were spatially separated and were not sites with trends in weekly Hg concentration. During 2002–2008, Hg wet deposition was found to be unchanged in the Great Lakes region and its subregions. Any small decreases in Hg concentration apparently were offset by increases in precipitation. - Highlights: ► Data from 5 Hg and precipitation networks in the USA and Canada were combined for the first time. ► High-resolution maps and statistical trends tests were used for spatial and temporal data analysis. ► Some 7-year mean annual Hg concentrations exceeded a 12 ng per liter water-quality criterion. ► Small, localized decreases in Hg concentration were offset by increases in precipitation. ► Hg wet deposition was unchanged in the Great Lakes region and its subregions during 2002–2008. - Analysis of monitoring data from 5 networks in the USA and Canada determined that mercury wet deposition was unchanged in the North American Great Lakes region during 2002–2008.

  9. Genetic diversity in the desert warthog (Phacochoerus aethiopicus delameri) population of eastern Africa

    DEFF Research Database (Denmark)

    Muwanika, Vincent B.; Kock, Richard; Masembe, Charles

    2012-01-01

    in a population of the desert warthog (Phacochoerus aethiopicus) sampled from 12 localities in its natural range in eastern Africa. From the total sample (30 individuals), at the six microsatellite loci that were analysed, a total of 43 alleles was observed averaging seven alleles per locus. Expected...... heterozygosity (HE) per locus was high, ranging from 0.53 to 0.87. At the mitochondrial loci, nucleotide diversity was low (p = 0.12%) with two unique haplotypes observed from the 19 individuals that amplified successfully. The diversity indices observed in the desert warthog are comparable to those previously...... reported for the closely related but widespread species, the common warthog (Phacochoerus africanus). These results suggest that the desert warthog is not genetically depauperate despite the rinderpest epidemic of the 1880s that eliminated it from most of its natural range....

  10. Relative abundance of desert tortoises on the Nevada Test Site

    International Nuclear Information System (INIS)

    Rautenstrauch, K.R.; O'Farrell, T.P.

    1993-01-01

    Seven hundred fifty-nine transects having a total length of 1,191 km were walked during 1981--1986 to determine the distribution and relative abundance of desert tortoises (Gopherus agassizii) on the Nevada Test Site (NTS). The abundance of tortoises on NTS was low to very low relative to other populations in the Mojave Desert. Sign of tortoises was found from 880 to 1,570 m elevation and was more abundant above 1,200 m than has been reported previously for Nevada. Tortoises were more abundant on NTS on the upper alluvial fans and slopes of mountains than in valley bottoms. They also were more common on or near limestone and dolomite mountains than on mountains of volcanic origin

  11. Precipitation, density, and population dynamics of desert bighorn sheep on San Andres National Wildlife Refuge, New Mexico

    Science.gov (United States)

    Bender, L.C.; Weisenberger, M.E.

    2005-01-01

    Understanding the determinants of population size and performance for desert bighorn sheep (Ovis canadensis mexicana) is critical to develop effective recovery and management strategies. In arid environments, plant communities and consequently herbivore populations are strongly dependent upon precipitation, which is highly variable seasonally and annually. We conducted a retrospective exploratory analysis of desert bighorn sheep population dynamics on San Andres National Wildlife Refuge (SANWR), New Mexico, 1941-1976, by modeling sheep population size as a function of previous population sizes and precipitation. Population size and trend of desert bighorn were best and well described (R 2=0.89) by a model that included only total annual precipitation as a covariate. Models incorporating density-dependence, delayed density-dependence, and combinations of density and precipitation were less informative than the model containing precipitation alone (??AlCc=8.5-22.5). Lamb:female ratios were positively related to precipitation (current year: F1,34=7.09, P=0.012; previous year: F1,33=3.37, P=0.075) but were unrelated to population size (current year. F1,34=0.04, P=0.843; previous year: F1,33 =0.14, P=0.715). Instantaneous population rate of increase (r) was related to population size (F1,33=5.55; P=0.025). Precipitation limited populations of desert bighorn sheep on SANWR primarily in a density-independent manner by affecting production or survival of lambs, likely through influences on forage quantity and quality. Habitat evaluations and recovery plans for desert bighorn sheep need to consider fundamental influences on desert bighorn populations such as precipitation and food, rather than focus solely on proximate issues such as security cover, predation, and disease. Moreover, the concept of carrying capacity for desert bighorn sheep may need re-evaluation in respect to highly variable (CV =35.6%) localized precipitation patterns. On SANWR carrying capacity for desert

  12. The Agassiz's desert tortoise genome provides a resource for the conservation of a threatened species.

    Directory of Open Access Journals (Sweden)

    Marc Tollis

    Full Text Available Agassiz's desert tortoise (Gopherus agassizii is a long-lived species native to the Mojave Desert and is listed as threatened under the US Endangered Species Act. To aid conservation efforts for preserving the genetic diversity of this species, we generated a whole genome reference sequence with an annotation based on deep transcriptome sequences of adult skeletal muscle, lung, brain, and blood. The draft genome assembly for G. agassizii has a scaffold N50 length of 252 kbp and a total length of 2.4 Gbp. Genome annotation reveals 20,172 protein-coding genes in the G. agassizii assembly, and that gene structure is more similar to chicken than other turtles. We provide a series of comparative analyses demonstrating (1 that turtles are among the slowest-evolving genome-enabled reptiles, (2 amino acid changes in genes controlling desert tortoise traits such as shell development, longevity and osmoregulation, and (3 fixed variants across the Gopherus species complex in genes related to desert adaptations, including circadian rhythm and innate immune response. This G. agassizii genome reference and annotation is the first such resource for any tortoise, and will serve as a foundation for future analysis of the genetic basis of adaptations to the desert environment, allow for investigation into genomic factors affecting tortoise health, disease and longevity, and serve as a valuable resource for additional studies in this species complex.

  13. 76 FR 29182 - Revisions to the California State Implementation Plan, Mojave Desert Air Quality Management District

    Science.gov (United States)

    2011-05-20

    ... ENVIRONMENTAL PROTECTION AGENCY 40 CFR Part 52 [EPA-R09-OAR-2011-0030; FRL-9308-4] Revisions to the California State Implementation Plan, Mojave Desert Air Quality Management District AGENCY... the Mojave Desert Air Quality Management District (MDAQMD) portion of the California State...

  14. 77 FR 11992 - Revisions to the California State Implementation Plan, Mojave Desert Air Quality Management District

    Science.gov (United States)

    2012-02-28

    ... the California State Implementation Plan, Mojave Desert Air Quality Management District AGENCY... limited disapproval of revisions to the Mojave Desert Air Quality Management District (MDAQMD) portion of...,'' Northeast States for Coordinated Air Use Management, December 2000. B. Does the rule meet the evaluation...

  15. Assessing water stress of desert vegetation using remote sensing : the case of the Tamarugo forest in the Atacama Desert (Northern Chile)

    NARCIS (Netherlands)

    Chávez Oyanadel, R.O.

    2014-01-01

    Water stress assessment of natural vegetation plays a key role in water management of desert ecosystems. It allows scientists and managers to relate water extraction rates to changes in vegetation water condition, and consequently to define safe water extraction rates for maintaining a healthy

  16. Sequential development of platform to off-platform facies of the great American carbonate bank in the central Appalachians: chapter 15

    Science.gov (United States)

    Brezinski, David K.; Taylor, John F.; Repetski, John E.

    2012-01-01

    In the central Appalachians, carbonate deposition of the great American carbonate bank began during the Early Cambrian with the creation of initial ramp facies of the Vintage Formation and lower members of the Tomstown Formation. Vertical stacking of bioturbated subtidal ramp deposits (Bolivar Heights Member) and dolomitized microbial boundtsone (Fort Duncan Member) preceded the initiation of platform sedimentation and creation of sand shoal facies (Benevola Member) that was followed by the development of peritidal cyclicity (Daragan Member). Initiation of peritidal deposition coincided with the development of a rimmed platform that would persist throughout much of the Cambrian and Early Odrovician. At the end of deposition of the Waynesboro Formation, the platform became subaerially exposed because of the Hawke Bay regression, bringing the Sauk I supersequence to and end. In the Conestoga Valley of eastern Pennsylvania, Early Cambrian ramp deposition was succeeded by deposition of platform-margin and periplatfrom facies of the Kinzers Formation.

  17. Tradeoffs and Synergies between biofuel production and large solar infrastructure in deserts.

    Science.gov (United States)

    Ravi, Sujith; Lobell, David B; Field, Christopher B

    2014-01-01

    Solar energy installations in deserts are on the rise, fueled by technological advances and policy changes. Deserts, with a combination of high solar radiation and availability of large areas unusable for crop production are ideal locations for large solar installations. However, for efficient power generation, solar infrastructures use large amounts of water for construction and operation. We investigated the water use and greenhouse gas (GHG) emissions associated with solar installations in North American deserts in comparison to agave-based biofuel production, another widely promoted potential energy source from arid systems. We determined the uncertainty in our analysis by a Monte Carlo approach that varied the most important parameters, as determined by sensitivity analysis. We considered the uncertainty in our estimates as a result of variations in the number of solar modules ha(-1), module efficiency, number of agave plants ha(-1), and overall sugar conversion efficiency for agave. Further, we considered the uncertainty in revenue and returns as a result of variations in the wholesale price of electricity and installation cost of solar photovoltaic (PV), wholesale price of agave ethanol, and cost of agave cultivation and ethanol processing. The life-cycle analyses show that energy outputs and GHG offsets from solar PV systems, mean energy output of 2405 GJ ha(-1) year(-1) (5 and 95% quantile values of 1940-2920) and mean GHG offsets of 464 Mg of CO2 equiv ha(-1) year(-1) (375-562), are much larger than agave, mean energy output from 206 (171-243) to 61 (50-71) GJ ha(-1) year(-1) and mean GHG offsets from 18 (14-22) to 4.6 (3.7-5.5) Mg of CO2 equiv ha(-1) year(-1), depending upon the yield scenario of agave. Importantly though, water inputs for cleaning solar panels and dust suppression are similar to amounts required for annual agave growth, suggesting the possibility of integrating the two systems to maximize the efficiency of land and water use to produce

  18. Deserts and holy mountains of medieval Serbia: Written sources, spatial patterns, architectural designs

    Directory of Open Access Journals (Sweden)

    Popović Danica

    2007-01-01

    Full Text Available Essential concepts in Christian thought and practice, the desert and holy mountain denote a particular kind of monastic and sacral space. They are secluded from the world, intended for asceticism, and ambivalent in nature they are inhospitable and menacing zones populated with demons, but also a monastic paradise, places for spiritual conversion and encounter with the divine. From earliest times, deserts and holy mountains had a few distinguishing characteristics. All forms of monastic life, from communal to solitary, were practiced side by side there. Monks of a special make-up and distinction known as holy men who were also often founders of illustrious communities, future saints and miracle-workers acted there. Furthermore these locales were important spiritual and bookmaking centre's, and therefore, strongholds of Orthodoxy. When trying to research Serbian material on this topic, we face a specific situation: few surviving sources on the one hand, and devastated monuments on the other. The ultimate consequence is that the entire subject has been neglected. Therefore the study of the Serbian deserts and holy mountains requires a very complex interdisciplinary approach with systematic field work as its essential part. It should address the following issues: corroboration, on the basis of written sources, of the reception of the concept of the monastic desert and holy mountain in a particular, regional, context; the distinct means and mechanisms employed in their physical realization; interpretation of their function; the recognition of patterns preserved in the surviving physical structures. Even the results obtained so far appear to be relevant enough to become included in the sacral topography of the Christian world. The author of this study gives particular attention to the detailed analysis of written sources of various genres - diplomatic sources, hagiographic material, liturgical texts, observation notes - in order to establish the

  19. Plantation of desert and renewal of earth with small LMRs

    International Nuclear Information System (INIS)

    Hattori, Sadao; Minato, Akio; Handa, Norihiko; Hashizume, Kenichi.

    1991-01-01

    Desertification is advancing at rapid rate on the earth. The technical development for preventing the desertification has been requested for advanced countries. Particularly in the southern hemisphere, the energy which can restore green in deserts and supply the electric power required for living is necessary. In this paper, the supply of electric power using the small fast reactors which are excellent in the safety and maintainability and the desalting plants required for tree planting in deserts, and further, the regeneration of the earth accompanying it, are discussed. By desertification, yearly 6 million ha of lands are devastated to unrecoverable extent, and those concentrate in the districts where yearly rainfall is little. In order to prevent desertification, it is necessary to stabilize surface soil by tree planting. Further, in order to prevent the deforestation for obtaining energy, the dual purpose plants for power generation and desalting are important. In this paper, the concept of obtaining water resources from sea, carrying out the desalting, supplying the water to the forefront of deserts and forming green belts there by using fast reactors is considered. The present status of desertification, the desalting of seawater by nuclear power, small fast reactors aiming at ultra-safety, the production of green, and the regeneration of the earth are described. (K.I.)

  20. Colonization patterns of soil microbial communities in the Atacama Desert.

    Science.gov (United States)

    Crits-Christoph, Alexander; Robinson, Courtney K; Barnum, Tyler; Fricke, W Florian; Davila, Alfonso F; Jedynak, Bruno; McKay, Christopher P; Diruggiero, Jocelyne

    2013-11-20

    The Atacama Desert is one of the driest deserts in the world and its soil, with extremely low moisture, organic carbon content, and oxidizing conditions, is considered to be at the dry limit for life. Analyses of high throughput DNA sequence data revealed that bacterial communities from six geographic locations in the hyper-arid core and along a North-South moisture gradient were structurally and phylogenetically distinct (ANOVA test for observed operating taxonomic units at 97% similarity (OTU0.03), P microbial communities' diversity metrics (least squares linear regression for observed OTU0.03 and air RH and soil conductivity, P PCoA Spearman's correlation for air RH and soil conductivity, P <0.0001), indicating that water availability and salt content are key factors in shaping the Atacama soil microbiome. Mineralization studies showed communities actively metabolizing in all soil samples, with increased rates in soils from the southern locations. Our results suggest that microorganisms in the driest soils of the Atacama Desert are in a state of stasis for most of the time, but can potentially metabolize if presented with liquid water for a sufficient duration. Over geological time, rare rain events and physicochemical factors potentially played a major role in selecting micro-organisms that are most adapted to extreme desiccating conditions.

  1. The End of the American Dream——On the Tragedy of Gatsby

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The Great Gatsby is considered as F. Scott Fitzgerald' s most important book. This paper will concentrate on the symbolic meaning of Gatsby's tragedy-the end of the mythical American dream. Gatsby's personal experience approximates the whole of the American dream. This paper gives a detailed analysis on the formation of his dream,his great efforts in realizing his dream and his disillusionment.

  2. Desert Dust Outbreaks in Southern Europe: Contribution to Daily PM10 Concentrations and Short-Term Associations with Mortality and Hospital Admissions

    Science.gov (United States)

    Stafoggia, Massimo; Zauli-Sajani, Stefano; Pey, Jorge; Samoli, Evangelia; Alessandrini, Ester; Basagaña, Xavier; Cernigliaro, Achille; Chiusolo, Monica; Demaria, Moreno; Díaz, Julio; Faustini, Annunziata; Katsouyanni, Klea; Kelessis, Apostolos G.; Linares, Cristina; Marchesi, Stefano; Medina, Sylvia; Pandolfi, Paolo; Pérez, Noemí; Querol, Xavier; Randi, Giorgia; Ranzi, Andrea; Tobias, Aurelio; Forastiere, Francesco

    2015-01-01

    Background: Evidence on the association between short-term exposure to desert dust and health outcomes is controversial. Objectives: We aimed to estimate the short-term effects of particulate matter ≤ 10 μm (PM10) on mortality and hospital admissions in 13 Southern European cities, distinguishing between PM10 originating from the desert and from other sources. Methods: We identified desert dust advection days in multiple Mediterranean areas for 2001–2010 by combining modeling tools, back-trajectories, and satellite data. For each advection day, we estimated PM10 concentrations originating from desert, and computed PM10 from other sources by difference. We fitted city-specific Poisson regression models to estimate the association between PM from different sources (desert and non-desert) and daily mortality and emergency hospitalizations. Finally, we pooled city-specific results in a random-effects meta-analysis. Results: On average, 15% of days were affected by desert dust at ground level (desert PM10 > 0 μg/m3). Most episodes occurred in spring–summer, with increasing gradient of both frequency and intensity north–south and west–east of the Mediterranean basin. We found significant associations of both PM10 concentrations with mortality. Increases of 10 μg/m3 in non-desert and desert PM10 (lag 0–1 days) were associated with increases in natural mortality of 0.55% (95% CI: 0.24, 0.87%) and 0.65% (95% CI: 0.24, 1.06%), respectively. Similar associations were estimated for cardio-respiratory mortality and hospital admissions. Conclusions: PM10 originating from the desert was positively associated with mortality and hospitalizations in Southern Europe. Policy measures should aim at reducing population exposure to anthropogenic airborne particles even in areas with large contribution from desert dust advections. Citation: Stafoggia M, Zauli-Sajani S, Pey J, Samoli E, Alessandrini E, Basagaña X, Cernigliaro A, Chiusolo M, Demaria M, Díaz J, Faustini A

  3. Desert Dust Outbreaks in Southern Europe: Contribution to Daily PM₁₀ Concentrations and Short-Term Associations with Mortality and Hospital Admissions.

    Science.gov (United States)

    Stafoggia, Massimo; Zauli-Sajani, Stefano; Pey, Jorge; Samoli, Evangelia; Alessandrini, Ester; Basagaña, Xavier; Cernigliaro, Achille; Chiusolo, Monica; Demaria, Moreno; Díaz, Julio; Faustini, Annunziata; Katsouyanni, Klea; Kelessis, Apostolos G; Linares, Cristina; Marchesi, Stefano; Medina, Sylvia; Pandolfi, Paolo; Pérez, Noemí; Querol, Xavier; Randi, Giorgia; Ranzi, Andrea; Tobias, Aurelio; Forastiere, Francesco

    2016-04-01

    Evidence on the association between short-term exposure to desert dust and health outcomes is controversial. We aimed to estimate the short-term effects of particulate matter ≤ 10 μm (PM10) on mortality and hospital admissions in 13 Southern European cities, distinguishing between PM10 originating from the desert and from other sources. We identified desert dust advection days in multiple Mediterranean areas for 2001-2010 by combining modeling tools, back-trajectories, and satellite data. For each advection day, we estimated PM10 concentrations originating from desert, and computed PM10 from other sources by difference. We fitted city-specific Poisson regression models to estimate the association between PM from different sources (desert and non-desert) and daily mortality and emergency hospitalizations. Finally, we pooled city-specific results in a random-effects meta-analysis. On average, 15% of days were affected by desert dust at ground level (desert PM10 > 0 μg/m3). Most episodes occurred in spring-summer, with increasing gradient of both frequency and intensity north-south and west-east of the Mediterranean basin. We found significant associations of both PM10 concentrations with mortality. Increases of 10 μg/m3 in non-desert and desert PM10 (lag 0-1 days) were associated with increases in natural mortality of 0.55% (95% CI: 0.24, 0.87%) and 0.65% (95% CI: 0.24, 1.06%), respectively. Similar associations were estimated for cardio-respiratory mortality and hospital admissions. PM10 originating from the desert was positively associated with mortality and hospitalizations in Southern Europe. Policy measures should aim at reducing population exposure to anthropogenic airborne particles even in areas with large contribution from desert dust advections. Stafoggia M, Zauli-Sajani S, Pey J, Samoli E, Alessandrini E, Basagaña X, Cernigliaro A, Chiusolo M, Demaria M, Díaz J, Faustini A, Katsouyanni K, Kelessis AG, Linares C, Marchesi S, Medina S, Pandolfi P, P

  4. A Brief Introduction of American Political Cultrue

    Institute of Scientific and Technical Information of China (English)

    张晓杰

    2009-01-01

    @@ The American Constitution in 1787 After the repeated compromise, the work of drawing up a constitution was completed on September 17,1787, a day which has been designated as Constitution Day of America. The appearance of constitution was a great event in American history. It established the Federal System which was the first in the world at that time.

  5. Water regime history drives responses of soil Namib Desert microbial communities to wetting events

    Science.gov (United States)

    Frossard, Aline; Ramond, Jean-Baptiste; Seely, Mary; Cowan, Don A.

    2015-07-01

    Despite the dominance of microorganisms in arid soils, the structures and functional dynamics of microbial communities in hot deserts remain largely unresolved. The effects of wetting event frequency and intensity on Namib Desert microbial communities from two soils with different water-regime histories were tested over 36 days. A total of 168 soil microcosms received wetting events mimicking fog, light rain and heavy rainfall, with a parallel “dry condition” control. T-RFLP data showed that the different wetting events affected desert microbial community structures, but these effects were attenuated by the effects related to the long-term adaptation of both fungal and bacterial communities to soil origins (i.e. soil water regime histories). The intensity of the water pulses (i.e. the amount of water added) rather than the frequency of wetting events had greatest effect in shaping bacterial and fungal community structures. In contrast to microbial diversity, microbial activities (enzyme activities) showed very little response to the wetting events and were mainly driven by soil origin. This experiment clearly demonstrates the complexity of microbial community responses to wetting events in hyperarid hot desert soil ecosystems and underlines the dynamism of their indigenous microbial communities.

  6. Neotropical mammal diversity and the Great American Biotic Interchange: spatial and temporal variation in South America's fossil record

    Science.gov (United States)

    Carrillo, Juan D.; Forasiepi, Analía; Jaramillo, Carlos; Sánchez-Villagra, Marcelo R.

    2015-01-01

    The vast mammal diversity of the Neotropics is the result of a long evolutionary history. During most of the Cenozoic, South America was an island continent with an endemic mammalian fauna. This isolation ceased during the late Neogene after the formation of the Isthmus of Panama, resulting in an event known as the Great American Biotic Interchange (GABI). In this study, we investigate biogeographic patterns in South America, just before or when the first immigrants are recorded and we review the temporal and geographical distribution of fossil mammals during the GABI. We performed a dissimilarity analysis which grouped the faunal assemblages according to their age and their geographic distribution. Our data support the differentiation between tropical and temperate assemblages in South America during the middle and late Miocene. The GABI begins during the late Miocene (~10–7 Ma) and the putative oldest migrations are recorded in the temperate region, where the number of GABI participants rapidly increases after ~5 Ma and this trend continues during the Pleistocene. A sampling bias toward higher latitudes and younger records challenges the study of the temporal and geographic patterns of the GABI. PMID:25601879

  7. Brood desertion by female shorebirds : a test of the differential parental capacity hypothesis on Kentish plovers

    NARCIS (Netherlands)

    Amat, JA; Visser, GH; Perez-Hurtado, A; Arroyo, GM

    2000-01-01

    The aim of this study was to examine whether the energetic costs of reproduction explain offspring desertion by female shorebirds, as is suggested by the differential parental capacity hypothesis. A prediction of the hypothesis is that, in species with biparental incubation in which females desert

  8. 76 FR 45606 - Desert Renewable Energy Conservation Plan, Habitat Conservation Plan and Possible Land Use Plan...

    Science.gov (United States)

    2011-07-29

    ...-N131; 80221-1112-80221-F2] Desert Renewable Energy Conservation Plan, Habitat Conservation Plan and Possible Land Use Plan Amendment, Southern California: Environmental Impact Statement AGENCY: Fish and..., as amended, for the proposed Desert Renewable Energy Conservation Plan (DRECP). The EIS will be a...

  9. Integrating gene transcription-based biomarkers to understand desert tortoise and ecosystem health

    Science.gov (United States)

    Bowen, Lizabeth; Miles, A. Keith; Drake, Karla K.; Waters, Shannon C.; Esque, Todd C.; Nussear, Kenneth E.

    2015-01-01

    Tortoises are susceptible to a wide variety of environmental stressors, and the influence of human disturbances on health and survival of tortoises is difficult to detect. As an addition to current diagnostic methods for desert tortoises, we have developed the first leukocyte gene transcription biomarker panel for the desert tortoise (Gopherus agassizii), enhancing the ability to identify specific environmental conditions potentially linked to declining animal health. Blood leukocyte transcript profiles have the potential to identify physiologically stressed animals in lieu of clinical signs. For desert tortoises, the gene transcript profile included a combination of immune or detoxification response genes with the potential to be modified by biological or physical injury and consequently provide information on the type and magnitude of stressors present in the animal’s habitat. Blood from 64 wild adult tortoises at three sites in Clark County, NV, and San Bernardino, CA, and from 19 captive tortoises in Clark County, NV, was collected and evaluated for genes indicative of physiological status. Statistical analysis using a priori groupings indicated significant differences among groups for several genes, while multidimensional scaling and cluster analyses of transcriptionC T values indicated strong differentiation of a large cluster and multiple outlying individual tortoises or small clusters in multidimensional space. These analyses highlight the effectiveness of the gene panel at detecting environmental perturbations as well as providing guidance in determining the health of the desert tortoise.

  10. Staging the Saints: Mormonism and American Musical Theater

    OpenAIRE

    Johnson, Jacob Vaughn

    2017-01-01

    American musical theater is often dismissed as frivolous or kitschy entertainment. But what if musicals actually mattered a great deal? What if perhaps the most innocuous musical genre in America actually defines the practices of Mormonism—America’s fastest-growing religion? I address these questions in this dissertation by applying methodologies from Musicology, Voice Studies, Performance Studies, and American Studies to the unexpected yet dynamic relationship between Mormonism and American ...

  11. Diurnal pattern of the drying front in desert and its application for determining the effective infiltration

    Directory of Open Access Journals (Sweden)

    Y. Zeng

    2009-06-01

    Full Text Available Located in western Inner Mongolia, the Badain Jaran Desert is the second largest desert in China and consists of a regular series of stable megadunes, among which over 70 permanent lakes exist. The unexpected lakes in desert attracted research interests on exploring the hydrological process under this particular landscape; however, a very few literatures exist on the diurnal and spatial variation of the drying front in this area, which is the main issue in the desert hydrological process to characterize the movement of water in soil. In order to understand the drying front in the Badain Jaran Desert, a field campaign was conducted by the observations of soil physical parameters and micrometeorological parameters. With the field data, the performance of a vadose zone soil water balance model, the HYDRUS, was verified and calibrated. Then, the HYDRUS was used to produce the spatial and temporal information of coupled water, water vapour and heat transport in sand to characterize the variation pattern of the drying front before, during and after the rainfall. Finally, the deepest drying front was applied to determine the effective infiltration, which is defined as the amount of soil water captured by the sand beneath the deepest drying front by infiltrating water of an incident rainfall event.

  12. Isotope method to study the replenishment the lakes and downstream groundwater in Badain Jaran desert

    International Nuclear Information System (INIS)

    Chen Jiansheng; Fan Zhechao; Gu Weizu; Zhao Xia; Wang Jiyang

    2003-01-01

    In the paper, the sources of spring water and well water of Qilian Mountain's north side, Longshou Mountain, Badain Jaran Desert, Gurinai, Guaizi Lake, and Ejina Basin are studied by the methods of environmental isotopes and water chemistry. The groundwater of downstream areas (such as Badain Jaran Desert) is found that it is recharged by the precipitation of Qilian Mountain, and the average recharge elevation is 3300 m. Lots of naked limestones layers exist at the mountaintop of Qilian Mountain. The snow water of Qilian Mountain melts and directly infiltrates into deep layer passing through karst stratum or Big Fault in Front of the Mountain, and directly recharges into Badain Jaran Desert and its downstream areas passing through Longshou Mountain. The calcareous cementation and travertine, found in the lakes of the desert, approve that the groundwater passed the limestone layer. Confined water recharges shallow aquifer by means of leakage. The groundwater recharge volume is six hundreds millions cubic meters per year by calculating the evaporation amount, and the age of confined groundwater is 20-30 years. (authors)

  13. Moderate irrigation intervals facilitate establishment of two desert shrubs in the Taklimakan Desert Highway Shelterbelt in China.

    Science.gov (United States)

    Li, Congjuan; Shi, Xiang; Mohamad, Osama Abdalla; Gao, Jie; Xu, Xinwen; Xie, Yijun

    2017-01-01

    Water influences various physiological and ecological processes of plants in different ecosystems, especially in desert ecosystems. The purpose of this study is to investigate the response of physiological and morphological acclimation of two shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in irrigation intervals. The irrigation frequency was set as 1-, 2-, 4-, 8- and 12-week intervals respectively from March to October during 2012-2014 to investigate the response of physiological and morphological acclimation of two desert shrubs Haloxylon ammodendron and Calligonum mongolicunl to variations in the irrigation system. The irrigation interval significantly affected the individual-scale carbon acquisition and biomass allocation pattern of both species. Under good water conditions (1- and 2-week intervals), carbon assimilation was significantly higher than other treatments; while, under water shortage conditions (8- and 12-week intervals), there was much defoliation; and under moderate irrigation intervals (4 weeks), the assimilative organs grew gently with almost no defoliation occurring. Both studied species maintained similar ecophysiologically adaptive strategies, while C. mongolicunl was more sensitive to drought stress because of its shallow root system and preferential belowground allocation of resources. A moderate irrigation interval of 4 weeks was a suitable pattern for both plants since it not only saved water but also met the water demands of the plants.

  14. Negative impacts of invasive plants on conservation of sensitive desert wildlife

    Science.gov (United States)

    Drake, K. Kristina; Bowen, Lizabeth; Nussear, Kenneth E.; Esque, Todd C.; Berger, Andrew J.; Custer, Nathan; Waters, Shannon C.; Johnson, Jay D.; Miles, A. Keith; Lewison, Rebecca L.

    2016-01-01

    Habitat disturbance from development, resource extraction, off-road vehicle use, and energy development ranks highly among threats to desert systems worldwide. In the Mojave Desert, United States, these disturbances have promoted the establishment of nonnative plants, so that native grasses and forbs are now intermixed with, or have been replaced by invasive, nonnative Mediterranean grasses. This shift in plant composition has altered food availability for Mojave Desert tortoises (Gopherus agassizii), a federally listed species. We hypothesized that this change in forage would negatively influence the physiological ecology, immune competence, and health of neonatal and yearling tortoises. To test this, we monitored the effects of diet on growth, body condition, immunological responses (measured by gene transcription), and survival for 100 captive Mojave tortoises. Tortoises were assigned to one of five diets: native forbs, native grass, invasive grass, and native forbs combined with either the native or invasive grass. Tortoises eating native forbs had better body condition and immune functions, grew more, and had higher survival rates (>95%) than tortoises consuming any other diet. At the end of the experiment, 32% of individuals fed only native grass and 37% fed only invasive grass were found dead or removed from the experiment due to poor body conditions. In contrast, all tortoises fed either the native forb or combined native forb and native grass diets survived and were in good condition. Health and body condition quickly declined for tortoises fed only the native grass (Festuca octoflora) or invasive grass (Bromus rubens) with notable loss of fat and muscle mass and increased muscular atrophy. Bromus rubens seeds were found embedded in the oral mucosa and tongue in most individuals eating that diet, which led to mucosal inflammation. Genes indicative of physiological, immune, and metabolic functions were transcribed at lower levels for individuals fed B

  15. Learning Desert Geomorphology Virtually versus in the Field

    Science.gov (United States)

    Stumpf, Richard J., II; Douglass, John; Dorn, Ronald I.

    2008-01-01

    Statistical analyses of pre-test and post-test results, as well as qualitative insight obtained by essays, compared introductory physical geography college students who learned desert geomorphology only virtually, in the field and both ways. With the exception of establishing geographic context, the virtual field trip was statistically…

  16. Origin of water in the Badain Jaran Desert, China: new insight from isotopes

    Science.gov (United States)

    Wu, Xiujie; Wang, Xu-Sheng; Wang, Yang; Hu, Bill X.

    2017-09-01

    To better understand the origin of water in the Badain Jaran Desert, China, water samples were collected from lakes, a spring and local unconfined aquifer for analyses of radiocarbon (14C), tritium (3H), stable hydrogen and oxygen isotope ratios (δ2H - δ18O), and d-excess values ( = δ2H - 8δ18O). A series of evaporation experiments were also conducted in the desert to examine how the isotopic signature of water may change during evaporation and infiltration under local environmental conditions. The results show that the lakes in the southeastern sand dune area are fed by groundwater discharging into the lakes and that local groundwater, on the other hand, is derived primarily from modern meteoric precipitation in the region. Although dissolved inorganic carbon (DIC) in groundwater yielded very old radiocarbon ages, the presence of detectable amounts of tritium in groundwater samples, together with their δ2H, δ18O and d-excess characteristics, strongly suggests that the old radiocarbon ages of DIC do not represent the residence time of water in the aquifer but are the result of addition of old DIC derived from dissolution of ancient carbonates in the aquifer. The data do not support the hypothesis that the water in the Badain Jaran Desert was sourced in remote mountains on the northern Tibetan Plateau. This study also finds no support for the hypothesis that present-day water resources in the desert were recharged by the precipitation that fell in the past during the early Holocene when the climate was much wetter than today. Instead, this study shows that both groundwater and lake water originated from meteoric precipitation in the region including mountainous areas adjacent to the desert under the modern climatic condition.

  17. Origin of water in the Badain Jaran Desert, China: new insight from isotopes

    Directory of Open Access Journals (Sweden)

    X. Wu

    2017-09-01

    Full Text Available To better understand the origin of water in the Badain Jaran Desert, China, water samples were collected from lakes, a spring and local unconfined aquifer for analyses of radiocarbon (14C, tritium (3H, stable hydrogen and oxygen isotope ratios (δ2H – δ18O, and d-excess values ( = δ2H – 8δ18O. A series of evaporation experiments were also conducted in the desert to examine how the isotopic signature of water may change during evaporation and infiltration under local environmental conditions. The results show that the lakes in the southeastern sand dune area are fed by groundwater discharging into the lakes and that local groundwater, on the other hand, is derived primarily from modern meteoric precipitation in the region. Although dissolved inorganic carbon (DIC in groundwater yielded very old radiocarbon ages, the presence of detectable amounts of tritium in groundwater samples, together with their δ2H, δ18O and d-excess characteristics, strongly suggests that the old radiocarbon ages of DIC do not represent the residence time of water in the aquifer but are the result of addition of old DIC derived from dissolution of ancient carbonates in the aquifer. The data do not support the hypothesis that the water in the Badain Jaran Desert was sourced in remote mountains on the northern Tibetan Plateau. This study also finds no support for the hypothesis that present-day water resources in the desert were recharged by the precipitation that fell in the past during the early Holocene when the climate was much wetter than today. Instead, this study shows that both groundwater and lake water originated from meteoric precipitation in the region including mountainous areas adjacent to the desert under the modern climatic condition.

  18. H-O isotopic and chemical characteristics of a precipitation-lake water-groundwater system in a desert area

    Science.gov (United States)

    Jin, Ke; Rao, Wenbo; Tan, Hongbing; Song, Yinxian; Yong, Bin; Zheng, Fangwen; Chen, Tangqing; Han, Liangfeng

    2018-04-01

    The recharge mechanism of groundwater in the Badain Jaran Desert, North China has been a focus of research and still disputable in the past two decades. In this study, the chemical and hydrogen (H) and oxygen (O) isotopic characteristics of shallow groundwater, lake water and local precipitation in the Badain Jaran Desert and neighboring areas were investigated to reveal the relationships between various water bodies and the recharge source of shallow groundwater. Isotopic and hydrogeochemical results show that (1) shallow groundwater was associated with local precipitation in the Ayouqi and Yabulai regions, (2) lake water was mainly recharged by groundwater in the desert hinterland, (3) shallow groundwater of the desert hinterland, Yabulai Mountain and Gurinai Grassland had a common recharge source. Shallow groundwater of the desert hinterland had a mean recharge elevation of 1869 m a.s.l. on the basis of the isotope-altitude relationship and thus originated chiefly from lateral infiltration of precipitation in the Yabulai Mountain. It is further concluded that shallow groundwater flowed towards the Gurinai Grassland according to the groundwater table contour map. Along the flow pathway, the H-O isotopic variations were primarily caused by the evaporation effect but chemical variations of shallow groundwater were affected by multiple factors, e.g., evaporation effect, dilution effect of occasional heavy-precipitation and dissolution of aquifer evaporites. Our findings provide new insight into the groundwater cycle and benefit the management of the limited water resources in the arid desert area.

  19. How much Carbon is Stored in Deserts? AN Approach for the Chilean Atacama Desert Using LANDSAT-8 Products

    Science.gov (United States)

    Hernández, H. J.; Acuña, T.; Reyes, P.; Torres, M.; Figueroa, E.

    2016-06-01

    The Atacama Desert in northern Chile is known as the driest place on Earth, with an average rainfall of about 15 mm per year. Despite these conditions, it contains a rich variety of flora with hundreds of species characterised by their extraordinary ability to adapt to this extreme environment. These biotic components have a direct link to important ecosystem services, especially those related to carbon storage and sequestration. No quantitative assessment is currently available for these services and the role of the desert in this matter remains unclear. We propose an approach to estimate above-ground biomass (AGB) using Landsat-8 data, which we tested in the Taparacá region, located in the northern section of the desert. To calibrate and validate the models, we used field data from 86 plots and several spectral indexes (NDVI, EVI and SAVI) obtained from the provisional Landsat-8 Surface-reflectance products. We applied randomised branch sampling and allometry principles (non-destructive methods) to collect biomass samples for all plant biological types: wetlands, steppes, shrubs and trees. All samples were dried in an oven until they reached constant weight and the final values were used to extrapolate dry matter content (AGB) to each plot in terms of kg m-2. We used all available scenes from September 2014 to August 2015 to calculate the maximum, minimum and average value for each index in each pixel within this period. For modeling, we used the method based on classification and regression trees called random forest (RF), available in the statistical software R-Project. The explained variance obtained by the RF algorithm was around 80-85%, and it improved when a wetland vector layer was used as the predictive factor in the model to reach the range 85-90%. The mean error was 1.45 kg m-2 of dry matter. The best model was obtained using the maximum and mean values of SAVI and EVI indexes. We were able to estimate total biomass storage of around 8 million tons

  20. The Great Depression: A Textbook Case of Problems with American History Textbooks.

    Science.gov (United States)

    Miller, Steven L.; Rose, Stephen A.

    1983-01-01

    The 16 US history textbooks reviewed failed to incorporate economists' research on the causes of the Great Depression and consistently presented information that the economics profession has rejected. Strategies that social studies educators might adopt to improve the quality of economic analysis in textbooks is suggested. (Author/RM)

  1. Historic distribution and challenges to bison recovery in the northern Chihuahuan Desert

    Science.gov (United States)

    List, Rurik; Ceballos, Gerardo; Curtin, Charles; Gogan, Peter J.; Pacheco, Jesus; Truett, Joe

    2007-01-01

    Ecologists and conservationists have long assumed that large grazers, including bison (Bison bison), did not occur in post-Pleistocene southwestern North America. This perception has been influential in framing the debate over conservation and land use in the northern Chihuahuan Desert. The lack of an evolutionary history of large grazers is being used to challenge the validity of ranching as a conservation strategy and to limit the protection and reintroduction of bison as a significant component of desert grassland ecosystems. Archeological records and historical accounts from Mexican archives from AD 700 to the 19th century document that the historic range of the bison included northern Mexico and adjoining areas in the United States. The Janos-Hidalgo bison herd, one of the few free-ranging bison herds in North America, has moved between Chihuahua, Mexico, and New Mexico, United States, since at least the 1920s. The persistence of this cross-border bison herd in Chihuahuan Desert grasslands and shrublands demonstrates that the species can persist in desert landscapes. Additional lines of evidence include the existence of grazing-adapted grasslands and the results of experimental studies that document declines in vegetation density and diversity following the removal of large grazers. The Janos-Hidalgo herd was formed with animals from various sources at the turn of the 19th century. Yet the future of the herd is compromised by differing perceptions of the ecological and evolutionary role of bison in the Desert Grasslands of North America. In Mexico they are considered native and are protected by federal law, whereas in New Mexico, they are considered non-native livestock and therefore lack conservation status or federal protection. Evidence written in Spanish of the presence of bison south of the accepted range and evidence from the disciplines of archaeology and history illustrate how differences in language and academic disciplines, in addition to

  2. Population health concerns during the United States' Great Recession.

    Science.gov (United States)

    Althouse, Benjamin M; Allem, Jon-Patrick; Childers, Matthew A; Dredze, Mark; Ayers, John W

    2014-02-01

    Associations between economic conditions and health are usually derived from cost-intensive surveys that are intermittently collected with nonspecific measures (i.e., self-rated health). This study identified how precise health concerns changed during the U.S. Great Recession analyzing Google search queries to identify the concern by the query content and their prevalence by the query volume. Excess health concerns were estimated during the Great Recession (December 2008 through 2011) by comparing the cumulative difference between observed and expected (based on linear projections from pre-existing trends) query volume for hundreds of individual terms. As performed in 2013, the 100 queries with the greatest excess were ranked and then clustered into themes based on query content. The specific queries with the greatest relative excess were stomach ulcer symptoms and headache symptoms, respectively, 228% (95% CI=35, 363) and 193% (95% CI=60, 275) greater than expected. Queries typically involved symptomology (i.e., gas symptoms) and diagnostics (i.e., heart monitor) naturally coalescing into themes. Among top themes, headache queries were 41% (95% CI=3, 148); hernia 37% (95% CI=16, 142); chest pain 35% (95% CI=6, 313); and arrhythmia 32% (95% CI=3, 149) greater than expected. Pain was common with back, gastric, joint, and tooth foci, with the latter 19% (95% CI=4, 46) higher. Among just the top 100, there were roughly 205 million excess health concern queries during the Great Recession. Google queries indicate that the Great Recession coincided with substantial increases in health concerns, hinting at how population health specifically changed during that time. © 2013 Published by American Journal of Preventive Medicine on behalf of American Journal of Preventive Medicine.

  3. 20th-Century Climate Change over Africa: Seasonal Variation in Hydroclimate Trends and Sahara Desert Extent

    Science.gov (United States)

    Nigam, S.; Thomas, N. P.

    2017-12-01

    Twentieth-century trends in seasonal temperature and precipitation over the African continent are analyzed from observational data sets and historical climate simulations. Given the agricultural economy of the continent, a seasonal perspective is adopted as it is more pertinent than an annual-average one which can mask off-setting but agriculturally-sensitive seasonal hydroclimate variations. Examination of linear trends in seasonal surface air temperature (SAT) shows that heat stress has increased in several regions, including Sudan and Northern Africa where largest SAT trends occur in the warm season. Broadly speaking, the northern continent has warmed more than the southern one in all seasons. Precipitation trends are varied but notable declining trends are found in the countries along the Gulf of Guinea, especially in the source region of Niger river in West Africa, and in the Congo river basin. Rainfall over the African Great Lakes - one of the largest freshwater repositories - has however increased. We show that the Sahara Desert has expanded significantly over the 20th century - by 12-20% depending on the season. The desert expanded southward in summer, reflecting retreat of the northern edge of the Sahel rainfall belt; and to the north in winter, indicating potential impact of the widening of the Tropics. Specific mechanisms driving the expansion in each season are investigated. Finally, this observational analysis is used to evaluate the state-of-the-art climate models from a comparison of the 20th-century hydroclimate trends with those manifest in historical climate simulations. The evaluation shows that modeling regional hydroclimate change over the Africa continent remains challenging.

  4. 75 FR 27383 - Culturally Significant Objects Imported for Exhibition Determinations: “A Gift From the Desert...

    Science.gov (United States)

    2010-05-14

    ... DEPARTMENT OF STATE [Public Notice 7003] Culturally Significant Objects Imported for Exhibition Determinations: ``A Gift From the Desert: The Art, History and Culture of the Arabian Horse'' SUMMARY: Notice is... objects to be included in the exhibition ``A Gift from the Desert: The Art, History and Culture of the...

  5. The economic impacts of desert power. Socio-economic aspects of an EUMENA renewable energy transition

    Energy Technology Data Exchange (ETDEWEB)

    Blohmke, Julian; Sohm, Matthew; Zickfeld, Florian

    2013-06-15

    The countries of the Middle East and North Africa (MENA) are one of the world's largest potential growth markets for renewable energy generation. Countries throughout the region have recognized the great potential of their excellent wind and solar conditions, and ample empty space, and have ambitious plans to develop solar and wind energy. They are already making progress in realizing these renewables targets. They also increasingly recognize the great potential of renewable energy in tackling a range of challenges. At a time of high unemployment, particularly among youth, the growth of renewable energy provides an engine for creating new jobs and fostering new skill profiles among workers. Renewables can increase GDP and form the basis for a significant new source of trade revenues. As a source of energy, renewables reduce dependency on fossil fuels - whether as imports, to supply energy, or as exports. This report, Economic Impacts of Desert Power (EIDP), investigates how, and under what conditions, renewables in MENA can lead to socioeconomic benefits. EIDP shows, under various scenarios, how many jobs can be expected in three exemplary MENA countries, and how the expansion of renewables can lead to higher GDP growth rates across the region. EIDP pinpoints their economic impact across sectors and countries. At the same time, EIDP describes how these effects can be maximized through immediate and sustained policy support. The report also details how such support can be tailored to foster a self-sustaining market. In short, EIDP aims to contribute to a range of debates focused on how to maximize the benefits of green growth. EIDP illustrates the following points: - MENA can benefit economically from decarbonizing - even if the rest of the world does not pursue climate action. - Exporting excess electricity is an economic opportunity for MENA countries - several North African countries could create a major export industry with renewable electricity, which

  6. Phenotypic flexibility at the molecular and organismal level allows desert-dwelling rodents to cope with seasonal water availability.

    Science.gov (United States)

    Gallardo, Pedro A; Cortes, Arturo; Bozinovic, Francisco

    2005-01-01

    We examined the phenotypic flexibility of field urine osmolality (Uosm) in response to seasonal rainfall and the experimental expression of renal aquaporins (AQPs) in the leaf-eared mouse Phyllotis darwini, a South American desert-dwelling rodent, through an integrative study at both the cellular and the organismal level. Field Uosm was higher in summer than in winter. Fall and winter Uosm were not significantly different. During a rainy year, winter Uosm was 2,140 +/- 82.3 mOsm kg(-1); the corresponding value in a dry year was 2,569 +/- 61.3 mOsm kg(-1). During the summer, the mean Uosm in a rainy year was 3,321 +/- 71.5 mOsm kg(-1), and in a dry year it was 3,604 +/- 107.2 mOsm kg(-1). The distribution of AQP-2, AQP-3, and AQP-4 was similar to that described for mouse and rat kidneys and confined to principal cells in cortex and inner medullary collecting-duct cells. AQP-4 immunoreactivity was unaltered by the state of water balance. Relative to water loading, dehydration induced an increase in AQP-2 immunoreactivity and protein abundance. Although more discrete, AQP-3 immunolabeling was also increased by dehydration. We now reveal how the integration of flexible renal mechanisms acting at the cellular and organismal level allow a small desert-dwelling mammal to cope with seasonal and yearly (El Nino) water availability in its semiarid habitat.

  7. Dynamics of penetration of 14C-labelled parathion in desert locust, Schistocerca gregaria Forskal

    International Nuclear Information System (INIS)

    Garg, A.K.; Bhatia, Parvathy; Sethi, G.R.

    1991-01-01

    Studies on the rate of disappearance of 14 C ring labelled parathion, after topical application on the mesosternum of desert locust, Schistocerca gregaria Forskal, indicated that penetration of the toxicant was linear and followed first order kinetics. The first order constant (k) for parathion on desert locust was 18.42x10 -2 per hr and half-life (Tsub(0.5)) was about 226 min. (author). 26 refs ., 1 fig

  8. Modeling Agassiz's Desert Tortoise Population Response to Anthropogenic Stressors

    Science.gov (United States)

    Mojave Desert tortoise (Gopherus agassizii) populations are exposed to a variety of anthropogenic threats, which vary in nature, severity, and frequency. Tortoise management in conservation areas can be compromised when the relative importance of these threats is not well underst...

  9. Fluvial-aeolian interactions in sediment routing and sedimentary signal buffering: an example from the Indus Basin and Thar Desert

    Science.gov (United States)

    East, Amy E.; Clift, Peter D.; Carter, Andrew; Alizai, Anwar; VanLaningham, Sam

    2015-01-01

    Sediment production and its subsequent preservation in the marine stratigraphic record offshore of large rivers are linked by complex sediment-transfer systems. To interpret the stratigraphic record it is critical to understand how environmental signals transfer from sedimentary source regions to depositional sinks, and in particular to understand the role of buffering in obscuring climatic or tectonic signals. In dryland regions, signal buffering can include sediment cycling through linked fluvial and eolian systems. We investigate sediment-routing connectivity between the Indus River and the Thar Desert, where fluvial and eolian systems exchanged sediment over large spatial scales (hundreds of kilometers). Summer monsoon winds recycle sediment from the lower Indus River and delta northeastward, i.e., downwind and upstream, into the desert. Far-field eolian recycling of Indus sediment is important enough to control sediment provenance at the downwind end of the desert substantially, although the proportion of Indus sediment of various ages varies regionally within the desert; dune sands in the northwestern Thar Desert resemble the Late Holocene–Recent Indus delta, requiring short transport and reworking times. On smaller spatial scales (1–10 m) along fluvial channels in the northern Thar Desert, there is also stratigraphic evidence of fluvial and eolian sediment reworking from local rivers. In terms of sediment volume, we estimate that the Thar Desert could be a more substantial sedimentary store than all other known buffer regions in the Indus basin combined. Thus, since the mid-Holocene, when the desert expanded as the summer monsoon rainfall decreased, fluvial-eolian recycling has been an important but little recognized process buffering sediment flux to the ocean. Similar fluvial-eolian connectivity likely also affects sediment routing and signal transfer in other dryland regions globally.

  10. Gardening in the desert: a spatial optimization approach to locating gardens in rapidly expanding urban environments.

    Science.gov (United States)

    Mack, Elizabeth A; Tong, Daoqin; Credit, Kevin

    2017-10-16

    Food access is a global issue, and for this reason, a wealth of studies are dedicated to understanding the location of food deserts and the benefits of urban gardens. However, few studies have linked these two strands of research together to analyze whether urban gardening activity may be a step forward in addressing issues of access for food desert residents. The Phoenix, Arizona metropolitan area is used as a case to demonstrate the utility of spatial optimization models for siting urban gardens near food deserts and on vacant land. The locations of urban gardens are derived from a list obtained from the Maricopa County Cooperative Extension office at the University of Arizona which were geo located and aggregated to Census tracts. Census tracts were then assigned to one of three categories: tracts that contain a garden, tracts that are immediately adjacent to a tract with a garden, and all other non-garden/non-adjacent census tracts. Analysis of variance is first used to ascertain whether there are statistical differences in the demographic, socio-economic, and land use profiles of these three categories of tracts. A maximal covering spatial optimization model is then used to identify potential locations for future gardening activities. A constraint of these models is that gardens be located on vacant land, which is a growing problem in rapidly urbanizing environments worldwide. The spatial analysis of garden locations reveals that they are centrally located in tracts with good food access. Thus, the current distribution of gardens does not provide an alternative food source to occupants of food deserts. The maximal covering spatial optimization model reveals that gardens could be sited in alternative locations to better serve food desert residents. In fact, 53 gardens may be located to cover 96.4% of all food deserts. This is an improvement over the current distribution of gardens where 68 active garden sites provide coverage to a scant 8.4% of food desert

  11. Landscape Sustainability in a Sonoran Desert City

    Directory of Open Access Journals (Sweden)

    Chris A. Martin

    2008-01-01

    Full Text Available The objective of this paper is to discuss concepts of landscape sustainability in the Phoenix metropolitan area. Phoenix is situated in the greater Salt River Valley of the lower Sonoran Desert in the southwest United States. In this paper I use the ecological frameworks of ecosystem services and resiliency as a metric for understanding landscape sustainability. An assessment of landscape sustainability performance benchmarks were made by surveying research findings of scientists affiliated with the Central Arizona Phoenix Long Term Ecological Research Project (CAP LTER. In Phoenix, present day emphases on cultural, aesthetic, and habitat formation ecosystem services within an arid ecoregion of low natural resilience coupled to a complex matrix of socioeconomic stratification, excessive landscape water use and pruning practices has had the undesired effect of degrading landscape sustainability. This has been measured as mixed patterns of plant diversity and human-altered patterns of carbon regulation, microclimate control, and trophic dynamics. In the future, sustainable residential landscaping in desert cities such as Phoenix may be fostered through use of water-conserving irrigation technologies, oasis-style landscape design motifs, recycling of landscape green waste, and conservative plant pruning strategies.

  12. American marsupials chromosomes: why study them?

    Directory of Open Access Journals (Sweden)

    Marta Svartman

    2009-01-01

    Full Text Available Marsupials, one of the three main groups of mammals, are only found in Australia and in the American continent. Studies performed in Australian marsupials have demonstrated the great potential provided by the group for the understanding of basic genetic mechanisms and chromosome evolution in mammals. Genetic studies in American marsupials are relatively scarce and cytogenetic data of most species are restricted to karyotype descriptions, usually without banding patterns. Nevertheless, the first marsupial genome sequenced was that of Monodelphis domestica, a South American species. The knowledge about mammalian genome evolution and function that resulted from studies on M. domestica is in sharp contrast with the lack of genetic data on most American marsupial species. Here, we present an overview of the chromosome studies performed in marsupials with emphasis on the South American species.

  13. Erosion Potential of a Burn Site in the Mojave-Great Basin Transition Zone: Interim Summary of One Year of Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Etyemezian, V.; Shafer, D.; Miller, J.; Kavouras, I.; Campbell, S.; DuBois, D.; King, J.; Nikolich, G.; Zitzer, S.

    2010-05-18

    A historic return interval of 100 years for large fires in deserts in the Southwest U.S. is being replaced by one where fires may reoccur as frequently as every 20 to 30 years. This increase in fires has implications for management of Soil Sub-Project Corrective Action Units (CAUs) for which the Department of Energy, National Nuclear Security Administration Nevada Site office (NNSA/NSO) has responsibility. A series of studies has been initiated at uncontaminated analog sites to better understand the possible impacts of erosion and transport by wind and water should contaminated soil sites burn over to understand technical and perceived risk they might pose to site workers and public receptors in communities around the NTS, TTR, and NTTR; and to develop recommendations for stabilization and restoration after a fire. The first of these studies was undertaken at the Jacob fire, a lightning-caused fire approximately 12 kilometers north of Hiko, Nevada, that burned approximately 200 ha between August 6-8, 2008, and is representative of a transition zone on the NTS between the Mojave and Great Basin Deserts, where the largest number of Soil Sub-Project CAUs/CASs are located.

  14. Effects of high fire frequency in creosote bush scrub vegetation of the Mojave Desert

    Science.gov (United States)

    Brooks, M.L.

    2012-01-01

    Plant invasions can increase fire frequency in desert ecosystems where fires were historically infrequent. Although there are many resource management concerns associated with high frequency fire in deserts, fundamental effects on plant community characteristics remain largely unstudied. Here I describe the effects of fire frequency on creosote bush scrub vegetation in the Mojave Desert, USA. Biomass of the invasive annual grass Bromus rubens L. increased following fire, but did not increase further with additional fires. In contrast, density, cover and species richness of native perennial plants each decreased following fire and continued to decrease with subsequent fires, although not as dramatically as after the initial fire. Responses were similar 5 and 14 years post-fire, except that cover of Hymenoclea salsola Torr. & A. Gray and Achnatherum speciosa Trin. & Rupr. both increased in areas burnt once. These results suggest that control of B. rubens may be equally warranted after one, two or three fires, but revegetation of native perennial plants is most warranted following multiple fires. These results are valid within the scope of this study, which is defined as relatively short term vegetation responses (???14 years) to short fire return intervals (6.3 and 7.3 years for the two and three fire frequency levels) within creosote bush scrub of the Mojave Desert. ?? 2012 IAWF.

  15. Variations in water balance and recharge potential at three western desert sites

    International Nuclear Information System (INIS)

    Gee, G.W.; Fayer, M.J.; Rockhold, M.L.; Wierenga, P.J.; Young, M.H.; Andraski, B.J.

    1994-01-01

    Radioactive and hazardous waste landfills exist at numerous desert locations in the USA. At these locations, annual precipitation is low and soils are generally dry, yet little is known about recharge of water and transport of contaminants to the water table. Recent water balance measurements made at three desert locations, Las Cruces, NM, Beatty, NV, and the U.S. Department of Energy's Hanford Site in the state of Washington, provide information on recharge potential under three distinctly different climate and soil conditions. All three sites show water storage increases with time when soils are coarse textured and plants are removed from the surface, the rate of increase being influenced by climatic variables such as precipitation, radiation, temperature, and wind. Lysimeter data from Hanford and Las Cruces indicate that deep drainage (recharge) from bare, sandy soils can range from 10 to > 50% of the annual precipitation. At Hanford, when desert plants are present on sandy or gravelly surface soils, deep drainage is reduced but not eliminated. When surface soils are silt loams, deep drainage is eliminated whether plants are present or not. At Las Cruces and Beatty, the presence of plants eliminated deep drainage at the measurement sites. Differences in water balance between sites are attributed to precipitation quantity and distribution and to soil and vegetation types. The implication of waste management at desert locations is that surface soil properties and plant characteristics must be considered in waste site design in order to minimize recharge potential. 39 refs., 9 figs., 3 tabs

  16. Fog deposition to a Tillandsia carpet in the Atacama Desert

    Science.gov (United States)

    Westbeld, A.; Klemm, O.; Grießbaum, F.; Sträter, E.; Larrain, H.; Osses, P.; Cereceda, P.

    2009-09-01

    In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water to a desert. In this exploratory study we estimate the amount of water available for the ecosystem by deposition and determine the relevant processes driving fog deposition. This is especially important for the species Tillandsia landbecki living in coastal Atacama at the limit of plant existence with fog and dew being the only sources of water. Between 31 July and 19 August 2008 approximately 2.5 L m-2 of water were made available through deposition. Whole-year deposition was estimated as 25 L m-2. Turbulent upward fluxes occurred several times during the evenings and are explained by the formation of radiation fog. In connection with that, underestimates of the deposition are assumed. More detailed studies covering various seasons and all parameters and fluxes contributing to the local energy balance are suggested. This will help to further develop understanding about the processes of (i) deposition of water to the desert, and (ii) intensification of advection fog through additional formation of radiation fog.

  17. Fog deposition to a Tillandsia carpet in the Atacama Desert

    Energy Technology Data Exchange (ETDEWEB)

    Westbeld, A.; Klemm, O.; Griessbaum, F.; Straeter, E. [Muenster Univ. (Germany). Inst. of Landscape Ecology; Larrain, H. [Pontificia Univ. Catolica de Chile (Chile). Atacama Desert Center ADC; Univ. Bolivariana, Iquique (Chile); Osses, P.; Cereceda, P. [Pontificia Univ. Catolica de Chile, Santiago de Chile (Chile). Inst. of Geography

    2009-07-01

    In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water to a desert. In this exploratory study we estimate the amount of water available for the ecosystem by deposition and determine the relevant processes driving fog deposition. This is especially important for the species Tillandsia landbecki living in coastal Atacama at the limit of plant existence with fog and dew being the only sources of water. Between 31 July and 19 August 2008 approximately 2.5 L m{sup -2} of water were made available through deposition. Whole-year deposition was estimated as 25 L m{sup -2}. Turbulent upward fluxes occurred several times during the evenings and are explained by the formation of radiation fog. In connection with that, underestimates of the deposition are assumed. More detailed studies covering various seasons and all parameters and fluxes contributing to the local energy balance are suggested. This will help to further develop understanding about the processes of (i) deposition of water to the desert, and (ii) intensification of advection fog through additional formation of radiation fog. (orig.)

  18. Fog deposition to a Tillandsia carpet in the Atacama Desert

    Directory of Open Access Journals (Sweden)

    P. Osses

    2009-09-01

    Full Text Available In the Atacama Desert, one of the driest places on earth, fog deposition plays an important role for the water balance and for the survival of vulnerable ecosystems. The eddy covariance method, previously applied for the quantification of fog deposition to forests in various parts of the world, was used for the first time to measure deposition of fog water to a desert. In this exploratory study we estimate the amount of water available for the ecosystem by deposition and determine the relevant processes driving fog deposition. This is especially important for the species Tillandsia landbecki living in coastal Atacama at the limit of plant existence with fog and dew being the only sources of water. Between 31 July and 19 August 2008 approximately 2.5 L m−2 of water were made available through deposition. Whole-year deposition was estimated as 25 L m−2. Turbulent upward fluxes occurred several times during the evenings and are explained by the formation of radiation fog. In connection with that, underestimates of the deposition are assumed. More detailed studies covering various seasons and all parameters and fluxes contributing to the local energy balance are suggested. This will help to further develop understanding about the processes of (i deposition of water to the desert, and (ii intensification of advection fog through additional formation of radiation fog.

  19. Out of the Desert: My Journey from Nomadic Bedouin to the Heart of Global Oil

    KAUST Repository

    Al-Naimi, Ali Ibrahim

    2017-01-08

    His Excellency Ali Ibrahim Al-Naimi, former Ministry of Oil in the Kingdom of Saudi Arabia, will comment on his forthcoming autobiography "Out of the Desert: My Journey from Nomadic Bedouin to the Heart of Global Oil". Ali Ibrahim Al-Naimi is the former Saudi oil minister - and OPEC kingpin - a position he held for the two decades between August 1995 and May 2016. He was born into extreme poverty as a nomadic Bedouin in the 1930s, just as US companies were discovering vast quantities of oil under Arabian deserts. From his first job as a shepherd boy to his appointment to one of the most powerful political and economic jobs in the world, Out of the Desert charts Al-Naimi\\'s extraordinary rise to power.

  20. Cutaneous adenocarcinoma in a desert tortoise (Gopherus agassizii

    Directory of Open Access Journals (Sweden)

    Ashraf Abu-Seida

    2013-06-01

    Full Text Available This report describes the clinical and histopathological findings of a rare case of cutaneous adenocarcinoma in a 40-year-old desert tortoise. Surgical excision of the neoplasm improved the general health condition and locomotion of the tortoise although recurrence of the neoplasm had been recorded 1 year post-surgery.

  1. Energetics and water relations ofN amib desert rodents

    African Journals Online (AJOL)

    and the possible effects of advective fog on the water balance of the .... Table 2 Energy balance of Namib desert rodents in the laboratory on a diet of air-dried bird seed and with, and with, ad lib water. .... responding mercury thermometer.

  2. Native American interpretation of cultural resources in the area of Yucca Mountain, Nevada

    International Nuclear Information System (INIS)

    Stoffle, R.W.; Evans, M.J.; Harshbarger, C.L.

    1989-03-01

    This report presents the location and interpretation of Native American cultural resources on or near Yucca Mountain, Nevada. This work builds on the archaeological reconnaissance and identifications of cultural resources by the Desert Research Institute (for a summary, see Pippin and Zerga, 1983; Pippin, 1984). Interpretations provided by Native American Indian people are not intended to refute other scientific studies, such as botanical, wildlife, and archaeological studies. Rather, they provide additional hypotheses for future studies, and they provide a more complete cultural understanding of the Yucca Mountain area. Representatives of sixteen American Indian tribes identified the cultural value of these resources as part of a consultation relationship with the US Department of Energy (DOE). This interim report is to be used to review research procedures and findings regarding initial consultation with the sixteen tribes, in-depth interviews with tribal elders, and findings from the first on-site visit with representatives of the sixteen tribes. As additional information is collected, it will be reviewed separately. An annual report will integrate all findings. 44 refs., 58 figs., 2 tabs

  3. Field Performance of Photovoltaic Systems in the Tucson Desert

    Science.gov (United States)

    Orsburn, Sean; Brooks, Adria; Cormode, Daniel; Greenberg, James; Hardesty, Garrett; Lonij, Vincent; Salhab, Anas; St. Germaine, Tyler; Torres, Gabe; Cronin, Alexander

    2011-10-01

    At the Tucson Electric Power (TEP) solar test yard, over 20 different grid-connected photovoltaic (PV) systems are being tested. The goal at the TEP solar test yard is to measure and model real-world performance of PV systems and to benchmark new technologies such as holographic concentrators. By studying voltage and current produced by the PV systems as a function of incident irradiance, and module temperature, we can compare our measurements of field-performance (in a harsh desert environment) to manufacturer specifications (determined under laboratory conditions). In order to measure high-voltage and high-current signals, we designed and built reliable, accurate sensors that can handle extreme desert temperatures. We will present several benchmarks of sensors in a controlled environment, including shunt resistors and Hall-effect current sensors, to determine temperature drift and accuracy. Finally we will present preliminary field measurements of PV performance for several different PV technologies.

  4. Properties of Desert Sand and CMAS Glass

    Science.gov (United States)

    Bansal, Narottam P.; Choi, Sung R.

    2014-01-01

    As-received desert sand from a Middle East country has been characterized for its phase composition and thermal stability. X-ray diffraction analysis showed the presence of quartz (SiO2), calcite (CaCO3), gypsum (CaSO4.2H2O), and NaAlSi3O8 phases in as-received desert sand and showed weight loss of approx. 35 percent due to decomposition of CaCO3 and CaSO4.2H2O when heated to 1400 C. A batch of as-received desert sand was melted into calcium magnesium aluminosilicate (CMAS) glass at approx. 1500 C. From inductively coupled plasma-atomic emission spectrometry, chemical composition of the CMAS glass was analyzed to be 27.8CaO-4MgO-5Al2O3-61.6SiO2-0.6Fe2O3-1K2O (mole percent). Various physical, thermal and mechanical properties of the glass have been evaluated. Bulk density of CMAS glass was 2.69 g/cc, Young's modulus 92 GPa, Shear modulus 36 GPa, Poisson's ratio 0.28, dilatometric glass transition temperature (T (sub g)) 706 C, softening point (T (sub d)) 764 C, Vickers microhardness 6.3 +/- 0.4 GPa, indentation fracture toughness 0.75 +/- 0.15 MPa.m (sup 1/2), and coefficient of thermal expansion (CTE) 9.8 x 10 (exp -6)/degC in the temperature range 25 to 700 C. Temperature dependence of viscosity has also been estimated from various reference points of the CMAS glass using the Vogel-Fulcher-Tamman (VFT) equation. The glass remained amorphous after heat treating at 850 C for 10 hr but crystallized into CaSiO3 and Ca-Mg-Al silicate phases at 900 C or higher temperatures. Crystallization kinetics of the CMAS glass has also been investigated by differential thermal analysis (DTA). Activation energies for the crystallization of two different phases in the glass were calculated to be 403 and 483 kJ/mol, respectively.

  5. Evolutionary hotspots in the Mojave Desert

    Science.gov (United States)

    Vandergast, Amy G.; Inman, Richard D.; Barr, Kelly R.; Nussear, Kenneth E.; Esque, Todd C.; Hathaway, Stacie A.; Wood, Dustin A.; Medica, Philip A.; Breinholt, Jesse W.; Stephen, Catherine L.; Gottscho, Andrew D.; Marks, Sharyn B.; Jennings, W. Bryan; Fisher, Robert N.

    2013-01-01

    Genetic diversity within species provides the raw material for adaptation and evolution. Just as regions of high species diversity are conservation targets, identifying regions containing high genetic diversity and divergence within and among populations may be important to protect future evolutionary potential. When multiple co-distributed species show spatial overlap in high genetic diversity and divergence, these regions can be considered evolutionary hotspots. We mapped spatial population genetic structure for 17 animal species across the Mojave Desert, USA. We analyzed these in concurrence and located 10 regions of high genetic diversity, divergence or both among species. These were mainly concentrated along the western and southern boundaries where ecotones between mountain, grassland and desert habitat are prevalent, and along the Colorado River. We evaluated the extent to which these hotspots overlapped protected lands and utility-scale renewable energy development projects of the Bureau of Land Management. While 30–40% of the total hotspot area was categorized as protected, between 3–7% overlapped with proposed renewable energy project footprints, and up to 17% overlapped with project footprints combined with transmission corridors. Overlap of evolutionary hotspots with renewable energy development mainly occurred in 6 of the 10 identified hotspots. Resulting GIS-based maps can be incorporated into ongoing landscape planning efforts and highlight specific regions where further investigation of impacts to population persistence and genetic connectivity may be warranted.

  6. Multi-scale forcing and the formation of subtropical desert and monsoon

    Directory of Open Access Journals (Sweden)

    G. X. Wu

    2009-09-01

    Full Text Available This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways to the occurrence of dry and wet climates in the subtropics. To explain the formation of desert over the western parts of continents and monsoon over the eastern parts, we propose a new mechanism of positive feedback between diabatic heating and vorticity generation that occurs via meridional advection of planetary vorticity and temperature. Monsoon and desert are demonstrated to coexist as twin features of multi-scale forcing, as follows. First, continent-scale heating over land and cooling over ocean induce the ascent of air over the eastern parts of continents and western parts of oceans, and descent over eastern parts of oceans and western parts of continents. Second, local-scale sea-breeze forcing along coastal regions enhances air descent over eastern parts of oceans and ascent over eastern parts of continents. This leads to the formation of the well-defined summertime subtropical LOSECOD quadruplet-heating pattern across each continent and adjacent oceans, with long-wave radiative cooling (LO over eastern parts of oceans, sensible heating (SE over western parts of continents, condensation heating (CO over eastern parts of continents, and double dominant heating (D: LO+CO over western parts of oceans. Such a quadruplet heating pattern corresponds to a dry climate over the western parts of continents and a wet climate over eastern parts. Third, regional-scale orographic-uplift-heating generates poleward ascending flow to the east of orography and equatorward descending flow to the west. The Tibetan Plateau (TP is located over the eastern Eurasian continent. The TP-forced circulation pattern is in phase with that produced by continental-scale forcing, and the strongest monsoon and largest deserts are formed over the Afro-Eurasian Continent. In contrast, the Rockies and the Andes are located over the western

  7. Multi-scale forcing and the formation of subtropical desert and monsoon

    Directory of Open Access Journals (Sweden)

    G. X. Wu

    2009-09-01

    Full Text Available This study investigates three types of atmospheric forcing across the summertime subtropics that are shown to contribute in various ways to the occurrence of dry and wet climates in the subtropics. To explain the formation of desert over the western parts of continents and monsoon over the eastern parts, we propose a new mechanism of positive feedback between diabatic heating and vorticity generation that occurs via meridional advection of planetary vorticity and temperature. Monsoon and desert are demonstrated to coexist as twin features of multi-scale forcing, as follows.

    First, continent-scale heating over land and cooling over ocean induce the ascent of air over the eastern parts of continents and western parts of oceans, and descent over eastern parts of oceans and western parts of continents. Second, local-scale sea-breeze forcing along coastal regions enhances air descent over eastern parts of oceans and ascent over eastern parts of continents. This leads to the formation of the well-defined summertime subtropical LOSECOD quadruplet-heating pattern across each continent and adjacent oceans, with long-wave radiative cooling (LO over eastern parts of oceans, sensible heating (SE over western parts of continents, condensation heating (CO over eastern parts of continents, and double dominant heating (D: LO+CO over western parts of oceans. Such a quadruplet heating pattern corresponds to a dry climate over the western parts of continents and a wet climate over eastern parts. Third, regional-scale orographic-uplift-heating generates poleward ascending flow to the east of orography and equatorward descending flow to the west.

    The Tibetan Plateau (TP is located over the eastern Eurasian continent. The TP-forced circulation pattern is in phase with that produced by continental-scale forcing, and the strongest monsoon and largest deserts are formed over the Afro-Eurasian Continent. In contrast, the Rockies and the Andes are

  8. Moistening of the northern North American Great Plains enhances land-atmosphere coupling

    Science.gov (United States)

    Gerken, T.; Bromley, G. T.; Stoy, P. C.

    2017-12-01

    Land use change impacts planetary boundary layer processes and regional climate by altering the magnitude and timing of water and energy flux into the atmosphere. In the North American Great Plains (NGP), a decline in the practice of summer fallow on the order of 20 Mha from the 1970s until the present has coincided with a decrease in summertime radiative forcing, on the order of 6 W m-2. MERRA 2 (Modern-Era Retrospective analysis for Research and Applications) for the area near Fort Peck, Montana, (a FLUXNET site established in 2000) shows a decrease of summertime (June-August) sensible heat fluxes ranging from -3.6 to -8.5 W m-2 decade-1, associated with an increase of latent heat fluxes (5.2-9.1 W m-2 decade-1) since the 1980s. Net radiation changed little. The result was a strong decrease of summer Bowen ratios from 1.5-2 in 1980 to approximately 1 in 2015. Findings are consistent with the effects on increased summertime evapotranspiration due to reduction in summer fallow that should lead to smaller Bowen ratios and a larger build-up of moist static energy. We use a mixed-layer (ML) atmospheric modeling framework to further investigate the impact of the surface energy balance on convective development and local land-atmosphere coupling in the NGP. Using summertime eddy covariance data from Fort Peck and atmospheric soundings from the nearby Glasgow airport, we compare the development of modeled ML and lifted condensation level (LCL) to find times of ML exceeding LCL, a necessary but not sufficient condition for the occurrence of convective precipitation. We establish that the ML model adequately captures ML heights and timing of locally triggered convection at the site and that there is a c. 10% increase in modeled convection permitting conditions today compared to 1975-85 in response to ML-moistening and decreasing Bo. We find that growing season land-atmosphere coupling develops from wet preference in May to dry coupling in July and atmospheric suppression

  9. Aircraft and satellite remote sensing of desert soils and landscapes

    Science.gov (United States)

    Petersen, G. W.; Connors, K. F.; Miller, D. A.; Day, R. L.; Gardner, T. W.

    1987-01-01

    Remote sensing data on desert soils and landscapes, obtained by the Landsat TM, Heat Capacity Mapping Mission (HCMM), Simulated SPOT, and Thermal IR Multispectral Scanner (TIMS) aboard an aircraft, are discussed together with the analytical techniques used in the studies. The TM data for southwestern Nevada were used to discriminate among the alluvial fan deposits with different degrees of desert pavement and varnish, and different vegetation cover. Thermal-IR data acquired from the HCMM satellite were used to map the spatial distribution of diurnal surface temperatures and to estimate mean annual soil temperatures in central Utah. Simulated SPOT data for northwestern New Mexico identified geomorphic features, such as differences in eolian sand cover and fluvial incision, while the TIMS data depicted surface geologic features of the Saline Valley in California.

  10. Ancient photosynthetic eukaryote biofilms in an Atacama Desert coastal cave

    Science.gov (United States)

    Azua-Bustos, A.; Gonzalez-Silva, C.; Mancilla, R.A.; Salas, L.; Palma, R.E.; Wynne, J.J.; McKay, C.P.; Vicuna, R.

    2009-01-01

    Caves offer a stable and protected environment from harsh and changing outside prevailing conditions. Hence, they represent an interesting habitat for studying life in extreme environments. Here, we report the presence of a member of the ancient eukaryote red algae Cyanidium group in a coastal cave of the hyperarid Atacama Desert. This microorganism was found to form a seemingly monospecific biofilm growing under extremely low photon flux levels. Our work suggests that this species, Cyanidium sp. Atacama, is a new member of a recently proposed novel monophyletic lineage of mesophilic "cave" Cyanidium sp., distinct from the remaining three other lineages which are all thermo-acidophilic. The cave described in this work may represent an evolutionary island for life in the midst of the Atacama Desert. ?? Springer Science + Business Media, LLC 2009.

  11. Algae-production in the desert

    Energy Technology Data Exchange (ETDEWEB)

    Hildebrand, H.

    1988-11-01

    The company Koor Food Ltd. (Israel) developed in co-operation with the Weizmann-Institute (Israel) a production-plant for the industrial cultivation of algae in the desert area of Elat. For almost a year now, they succeed in harvesting large amounts of algae material with the help of the intensive sun and the Red Sea water. The alga Dunaliella with the natural US -carotine, as well as the alga Spirulina with the high content of protein find their market in the food-, cosmetic- and pharma-industry. This article will give a survey of a yet here unusual project.

  12. Δ17O Isotopic Investigation of Nitrate Salts Found in Co-Occurrence with Naturally Formed Perchlorate in the Mojave Desert, California, USA and the Atacama Desert, Chile

    Science.gov (United States)

    Lybrand, R. A.; Parker, D.; Rech, J.; Prellwitz, J.; Michalski, G.

    2009-12-01

    Perchlorate is both a naturally occurring and manmade contaminant that has been identified in soil, groundwater and surface water. Perchlorate directly affects human health by interfering with iodide uptake in the thyroid gland, which may in turn lower the production of key hormones that are needed for proper growth and development. Until recently, the Atacama Desert, Chile was thought to be the only location where perchlorate salts formed naturally. Recent work has documented the occurrence of these salts in several semi-arid regions of the United States. This study identified putatively natural sources of perchlorate in the Mojave Desert of California. Soil samples were collected from six field sites varying in geologic age. The co-occurrence of perchlorate and nitrate in caliches from the Atacama Desert and soils from the Mojave Desert was also investigated. Although the former are richer in NO3-, near-ore-grade (~5%) deposits occur in the vicinity of Death Valley National Park. Weak but significant correlations exist between ClO4- and NO3- at both locations, but the perchlorate levels are much higher (up to 800 mg/kg) in the Chilean samples than in California (atmospheric origin for the Atacama nitrate salts, and a mixture between biological nitrate and atmospherically-derived nitrate for the Mojave samples. When corrected for the percentage of atmospheric nitrate measured in the Atacama samples, the Mojave samples still contain much lower perchlorate concentrations than would be expected if the occurrence of perchlorate correlated strictly with atmospherically derived nitrate. These results indicate that the variation in the origins of the nitrate salts is not the only factor influencing perchlorate distribution in these environments. These findings suggest that there are other geologic differences in landform age and stability that are crucial to understanding the co-occurrence of nitrate and perchlorate between the two locations.

  13. Impact of highly saline wetland ecosystem on floral diversity of the Cholistan desert

    International Nuclear Information System (INIS)

    Gill, A.H.; Ahmad, K.S.; Habib, S.; Ahmad, S.A.; Nawaz, T.; Ahmad, F.

    2012-01-01

    The impact of highly saline wetland ecosystem created under Salinity Control and Reclamation Project (SCARP) on floral diversity was investigated in the arid environments of Cholistan Desert. Species richness, diversity indices and evenness indices were worked out to look at the distance at which the salt water has altered the native vegetation. Four sites including SCARP ponds of different ages (S1, S2, S3 and S4), and a reference site (SR) were selected for vegetation studies and data were recorded by 1 x 1 m quadrats, which were laid on permanent transect lines. Salt water showed great influence on ecological parameters of the native vegetation up to 40 m. Multivariate (cluster) analysis showed close clustering of highly salt tolerant species, Aeluropus lagopoides, Tamarix dioica and Suaeda fruticosa in one group, and relatively less tolerant Crotalaria burhia, Cyperus conglomeratus, Indigofera argentea, Haloxylon salicornicum, Haloxylon stocksii, Neurada procumbens and Salsola baryosma in second group. Moderately salt tolerant Aristida adscensionis, Lasiurus scindicus and Sporobolus iocladus were clustered in a separate group. (author)

  14. 10Be in desert sands, falling dust and loess in China

    International Nuclear Information System (INIS)

    Shen, C.D.; Beer, J.; Kubik, P.W.; Sun, W.D.; Liu, T.S.; Liu, K.X.

    2010-01-01

    Cosmogenic 10 Be is produced in the atmosphere, and deposits onto the surface of the earth mainly through wet precipitation and dust. Based on the analysis of 10 Be in Chinese loess, we believe that 10 Be in loess is composed of two components: locally precipitated atmospheric 10 Be, and windblown 10 Be adsorbed on the surface of silt grains. On the Loess Plateau, 10 Be concentrations in loess and paleosol range from (1.4 to 2.8) x 10 8 atoms/g and (2.7 to 4.5) x 10 8 atoms/g, respectively. To investigate the sources of 10 Be in loess, we measured 10 Be in sand grains from deserts in western China and falling dust from the deposition regions. The results show that the 10 Be concentrations in sand and dust are (1.1-5.1) x 10 7 atoms/g and (1.3-2.8) x 10 8 atoms/g, respectively. Loess and paleosol on the Loess Plateau both contain inherited 10 Be adsorbed on silt grains from dust; most of the windblown deposited loess materials do not directly come from the Gobi and other sand deserts, but mainly from the loess-desert transitional zones, which are characterized by silt and dust holding areas.

  15. Solar energy conversion: an analysis of impacts on desert ecosystems. Progress report, June 1, 1977--December 31, 1977

    Energy Technology Data Exchange (ETDEWEB)

    Patten, D.T.

    1977-09-01

    Some of the important potential ecological impacts that might occur when solar collector arrays are constructed and maintained in the desert Southwest are discussed. These impacts are categorized under major environmental consequences of solar collector development, that is, shading, wind deflection and site destruction and soil disturbance. Under these major categories secondary impacts are developed to show the significance of altering desert ecosystems with solar conversion systems. Some of the secondary impacts which include abiotic changes in radiation, temperature, heat flux, soil moisture and erosion, and biotic changes such as increased plant productivity and species diversity are discussed as to their short and long term significance in the desert system. A brief description of the solar collector simulator array being constructed in the desert to test many of the concepts developed during the early part of Phase I of this project is presented.

  16. Effectiveness of post-fire seeding in desert tortoise Critical Habitat following the 2005 Southern Nevada Fire Complex

    Science.gov (United States)

    DeFalco, Lesley; Drake, Karla K.; Scoles-Sciulla, S. J.; Bauer, Kyla L.

    2010-01-01

    In June 2005, lightning strikes ignited multiple wildfires in southern Nevada. The Southern Nevada Fire Complex burned more than 32,000 acres of designated desert tortoise Critical Habitat and an additional 403,000 acres of Mojave Desert habitat characterized as potentially suitable for the tortoise. Mortalities of desert tortoises were observed after the fires, but altered habitat is likely to prolong and magnify the impacts of wildfire on desert tortoise populations. To accelerate the re-establishment of plants commonly used by tortoises for food and shelter, the Bureau of Land Management (BLM) distributed seeds of native annual and perennial species in burned areas within desert tortoise Critical Habitat. The U.S. Geological Survey (USGS) established monitoring plots to evaluate broadcast seeding as a means to restore habitat and tortoise activity compared with natural recovery. Within the standard three-year Emergency and Stabilization Response (ESR) monitoring timeline, seeding augmented perennial seed banks by four to six-fold within a year of seed applications compared with unseeded areas. By the end of the three-year monitoring period, seedling densities of seeded perennial species were 33% higher in seeded areas than in unseeded areas, particularly for the disturbance-adapted desert globemallow (Sphaeralcea ambigua) and desert marigold (Baileya multiradiata). Seeded annuals, in contrast, did not increase significantly in seed banks or biomass production, likely due to low seeding rates of these species. Production of non-native annuals that helped carry the fires was not reduced by seeding efforts but instead was strongly correlated with site-specific rainfall, as were native annual species. The short-term vegetation changes measured in seeded areas were not yet associated with a return of tortoise activity to unburned levels. By focusing on a combination of native species that can withstand disturbance conditions, including species that are found in

  17. Evaluation of the North American Land Data Assimilation System over the southern Great Plains during the warm season

    Science.gov (United States)

    Robock, Alan; Luo, Lifeng; Wood, Eric F.; Wen, Fenghua; Mitchell, Kenneth E.; Houser, Paul R.; Schaake, John C.; Lohmann, Dag; Cosgrove, Brian; Sheffield, Justin; Duan, Qingyun; Higgins, R. Wayne; Pinker, Rachel T.; Tarpley, J. Dan; Basara, Jeffery B.; Crawford, Kenneth C.

    2003-11-01

    North American Land Data Assimilation System (NLDAS) land surface models have been run for a retrospective period forced by atmospheric observations from the Eta analysis and actual precipitation and downward solar radiation to calculate land hydrology. We evaluated these simulations using in situ observations over the southern Great Plains for the periods of May-September of 1998 and 1999 by comparing the model outputs with surface latent, sensible, and ground heat fluxes at 24 Atmospheric Radiation Measurement/Cloud and Radiation Testbed stations and with soil temperature and soil moisture observations at 72 Oklahoma Mesonet stations. The standard NLDAS models do a fairly good job but with differences in the surface energy partition and in soil moisture between models and observations and among models during the summer, while they agree quite well on the soil temperature simulations. To investigate why, we performed a series of experiments accounting for differences between model-specified soil types and vegetation and those observed at the stations, and differences in model treatment of different soil types, vegetation properties, canopy resistance, soil column depth, rooting depth, root density, snow-free albedo, infiltration, aerodynamic resistance, and soil thermal diffusivity. The diagnosis and model enhancements demonstrate how the models can be improved so that they can be used in actual data assimilation mode.

  18. Characteristics and significance of uranium bearing pan african younger granite in the eastern desert, Egypt

    International Nuclear Information System (INIS)

    Hassan, M.A.; Dabbour, G.A.; Mohammden, T.F.

    1998-01-01

    Surficial uranium mineralization was discovered in four pan african younger granite plutons in the eastern desert of egypt. The present study revealed great similarity between these plutons both in petrography and geochemistry. They are two-feldspar, two-mica peraluminous granites which have been formed by melting of crustal materials and emplaced during the late stage stage of a late proterozoic orogenic cycle. Radiometric and geochemical investigations indicate that these granites are fertile with respect to U and form a potential target for primary uranium deposits. Four models are suggested to explain the source and mechanism of the surficial uranium mineralization in these granites. The most applicable model is the oxidation of U +4 found in minute disseminated uraninite grains and its subsequent mobilization. This is supported by petrographic and autoradiographic studies. The bearings of the present study on further exploration for uranium deposits in granites of the arabian- Nubian shield in general are discussed

  19. Wilderness restoration: Bureau of Land Management and the Student Conservation Association in the California Desert District

    Science.gov (United States)

    J. Dan Abbe

    2007-01-01

    The California Desert Protection Act of 1994 was the largest park and wilderness legislation passed in the Lower 48 States since the Wilderness Act of 1964. It designated three national parks and 69 Bureau of Land Management wilderness areas. The California Desert and Wilderness Restoration Project is working to restore and revitalize these lands through a public/...

  20. High Resolution Mapping of Soils and Landforms for the Desert Renewable Energy Conservation Plan (DRECP)

    Science.gov (United States)

    Potter, Christopher S.; Li, Shuang

    2014-01-01

    The Desert Renewable Energy Conservation Plan (DRECP), a major component of California's renewable energy planning efforts, is intended to provide effective protection and conservation of desert ecosystems, while allowing for the sensible development of renewable energy projects. This NASA mapping report was developed to support the DRECP and the Bureau of Land Management (BLM). We outline in this document remote sensing image processing methods to deliver new maps of biological soils crusts, sand dune movements, desert pavements, and sub-surface water sources across the DRECP area. We focused data processing first on the largely unmapped areas most likely to be used for energy developments, such as those within Renewable Energy Study Areas (RESA) and Solar Energy Zones (SEZs). We used imagery (multispectral and radar) mainly from the years 2009-2011.

  1. Thermal design of a fully equipped solar-powered desert home

    KAUST Repository

    Serag-Eldin, M.A.

    2010-01-01

    The paper presents a conceptual design and thermodynamic analysis of a solar-powered desert home. The home is airconditioned and provides all modern comforts and facilities. Electrical power, which drives the entire energy system, is generated

  2. Optimized estimation and its uncertainties of gross primary production over oasis-desert ecosystems in an arid region of China

    Science.gov (United States)

    Wang, H.; Li, X.; Xiao, J.; Ma, M.

    2017-12-01

    Arid and semi-arid ecosystems cover more than one-third of the Earth's land surface, it is of great important to the global carbon cycle. However, the magnitude of carbon sequestration and its contribution to global atmospheric carbon cycle is poorly understood due to the worldwide paucity of measurements of carbon exchange in the arid ecosystems. Accurate and continuous monitoring the production of arid ecosystem is of great importance for regional carbon cycle estimation. The MOD17A2 product provides high frequency observations of terrestrial Gross Primary Productivity (GPP) over the world. Although there have been plenty of studies to validate the MODIS GPP products with ground based measurements over a range of biome types, few have comprehensively validated the performance of MODIS estimates in arid and semi-arid ecosystems. Thus, this study examined the performance of the MODIS-derived GPP comparing with the EC observed GPP at different timescales for the main arid ecosystems in the arid and semi-arid ecosystems in China, and optimized the performance of the MODIS GPP calculations by using the in-situ metrological forcing data, and optimization of biome-specific parameters with the Bayesian approach. Our result revealed that the MOD17 algorithm could capture the broad trends of GPP at 8-day time scales for all investigated sites on the whole. However, the GPP product was underestimated in most ecosystems in the arid region, especially the irrigated cropland and forest ecosystems, while the desert ecosystem was overestimated in the arid region. On the annual time scale, the best performance was observed in grassland and cropland, followed by forest and desert ecosystems. On the 8-day timescale, the RMSE between MOD17 products and in-situ flux observations of all sites was 2.22 gC/m2/d, and R2 was 0.69. By using the in-situ metrological data driven, optimizing the biome-based parameters of the algorithm, we improved the performances of the MODIS GPP calculation

  3. EFFECTS OF ELEVATED CO2 ON ROOT FUNCTION AND SOIL RESPIRATION IN A MOJAVE DESERT ECOSYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Robert S.

    2007-12-19

    Increases in atmospheric CO{sub 2} concentration during the last 250 years are unequivocal, and CO{sub 2} will continue to increase at least for the next several decades (Houghton et al. 2001, Keeling & Whorf 2002). Arid ecosystems are some of the most important biomes globally on a land surface area basis, are increasing in area at an alarming pace (Dregne 1991), and have a strong coupling with regional climate (Asner & Heidebrecht 2005). These water-limited ecosystems also are predicted to be the most sensitive to elevated CO{sub 2}, in part because they are stressful environments where plant responses to elevated CO{sub 2} may be amplified (Strain & Bazzaz 1983). Indeed, all C{sub 3} species examined at the Nevada Desert FACE Facility (NDFF) have shown increased A{sub net} under elevated CO{sub 2} (Ellsworth et al. 2004, Naumburg et al. 2003, Nowak et al. 2004). Furthermore, increased shoot growth for individual species under elevated CO{sub 2} was spectacular in a very wet year (Smith et al. 2000), although the response in low to average precipitation years has been smaller (Housman et al. 2006). Increases in perennial cover and biomass at the NDFF are consistent with long term trends in the Mojave Desert and elsewhere in the Southwest, indicating C sequestration in woody biomass (Potter et al. 2006). Elevated CO{sub 2} also increases belowground net primary production (BNPP), with average increases of 70%, 21%, and 11% for forests, bogs, and grasslands, respectively (Nowak et al. 2004). Although detailed studies of elevated CO{sub 2} responses for desert root systems were virtually non-existent prior to our research, we anticipated that C sequestration may occur by desert root systems for several reasons. First, desert ecosystems exhibit increases in net photosynthesis and primary production at elevated CO{sub 2}. If large quantities of root litter enter the ecosystem at a time when most decomposers are inactive, significant quantities of carbon may be stored

  4. Anthropogenic water sources and the effects on Sonoran Desert small mammal communities.

    Science.gov (United States)

    Switalski, Aaron B; Bateman, Heather L

    2017-01-01

    Anthropogenic water sources (AWS) are developed water sources used as a management tool for desert wildlife species. Studies documenting the effects of AWS are often focused on game species; whereas, the effects on non-target wildlife are less understood. We used live trapping techniques to investigate rodent abundance, biomass, and diversity metrics near AWS and paired control sites; we sampled vegetation to determine rodent-habitat associations in the Sauceda Mountains of the Sonoran Desert in Arizona. A total of 370 individual mammals representing three genera and eight species were captured in 4,800 trap nights from winter 2011 to spring 2012. A multi-response permutation procedure was used to identify differences in small mammal community abundance and biomass by season and treatment. Rodent abundance, biomass, and richness were greater at AWS compared to control sites. Patterns of abundance and biomass were driven by the desert pocket mouse ( Chaetodipus penicillatus ) which was the most common capture and two times more numerous at AWS compared to controls. Vegetation characteristics, explored using principal components analysis, were similar between AWS and controls. Two species that prefer vegetation structure, Bailey's pocket mouse ( C. baileyi ) and white-throated woodrat ( Neotoma albigula) , had greater abundances and biomass near AWS and were associated with habitat having high cactus density. Although small mammals do not drink free-water, perhaps higher abundances of some species of desert rodents at AWS could be related to artificial structure associated with construction or other resources. Compared to the 30-year average of precipitation for the area, the period of our study occurred during a dry winter. During dry periods, perhaps AWS provide resources to rodents related to moisture.

  5. Anthropogenic water sources and the effects on Sonoran Desert small mammal communities

    Directory of Open Access Journals (Sweden)

    Aaron B. Switalski

    2017-11-01

    Full Text Available Anthropogenic water sources (AWS are developed water sources used as a management tool for desert wildlife species. Studies documenting the effects of AWS are often focused on game species; whereas, the effects on non-target wildlife are less understood. We used live trapping techniques to investigate rodent abundance, biomass, and diversity metrics near AWS and paired control sites; we sampled vegetation to determine rodent-habitat associations in the Sauceda Mountains of the Sonoran Desert in Arizona. A total of 370 individual mammals representing three genera and eight species were captured in 4,800 trap nights from winter 2011 to spring 2012. A multi-response permutation procedure was used to identify differences in small mammal community abundance and biomass by season and treatment. Rodent abundance, biomass, and richness were greater at AWS compared to control sites. Patterns of abundance and biomass were driven by the desert pocket mouse (Chaetodipus penicillatus which was the most common capture and two times more numerous at AWS compared to controls. Vegetation characteristics, explored using principal components analysis, were similar between AWS and controls. Two species that prefer vegetation structure, Bailey’s pocket mouse (C. baileyi and white-throated woodrat (Neotoma albigula, had greater abundances and biomass near AWS and were associated with habitat having high cactus density. Although small mammals do not drink free-water, perhaps higher abundances of some species of desert rodents at AWS could be related to artificial structure associated with construction or other resources. Compared to the 30-year average of precipitation for the area, the period of our study occurred during a dry winter. During dry periods, perhaps AWS provide resources to rodents related to moisture.

  6. The Depiction of Native Americans in Recent (1991-1998) Secondary American History Textbooks.

    Science.gov (United States)

    Sanchez, Antonio R.

    As a follow-up to studies by R. Costo and J. Henry (1970) and J. Loewen (1995), this study examined 12 current secondary level U.S. history textbooks to evaluate their accuracy in depicting Native Americans. The criteria embodied an authenticity guideline based upon the "Five Great Values" (generosity and sharing, respect for elders and…

  7. [Estimation of desert vegetation coverage based on multi-source remote sensing data].

    Science.gov (United States)

    Wan, Hong-Mei; Li, Xia; Dong, Dao-Rui

    2012-12-01

    Taking the lower reaches of Tarim River in Xinjiang of Northwest China as study areaAbstract: Taking the lower reaches of Tarim River in Xinjiang of Northwest China as study area and based on the ground investigation and the multi-source remote sensing data of different resolutions, the estimation models for desert vegetation coverage were built, with the precisions of different estimation methods and models compared. The results showed that with the increasing spatial resolution of remote sensing data, the precisions of the estimation models increased. The estimation precision of the models based on the high, middle-high, and middle-low resolution remote sensing data was 89.5%, 87.0%, and 84.56%, respectively, and the precisions of the remote sensing models were higher than that of vegetation index method. This study revealed the change patterns of the estimation precision of desert vegetation coverage based on different spatial resolution remote sensing data, and realized the quantitative conversion of the parameters and scales among the high, middle, and low spatial resolution remote sensing data of desert vegetation coverage, which would provide direct evidence for establishing and implementing comprehensive remote sensing monitoring scheme for the ecological restoration in the study area.

  8. Ultrasound-assisted extraction of polyphenols from native plants in the Mexican desert.

    Science.gov (United States)

    Wong Paz, Jorge E; Muñiz Márquez, Diana B; Martínez Ávila, Guillermo C G; Belmares Cerda, Ruth E; Aguilar, Cristóbal N

    2015-01-01

    Several plants that are rich in polyphenolic compounds and exhibit biological properties are grown in the desert region of Mexico under extreme climate conditions. These compounds have been recovered by classic methodologies in these plants using organic solvents. However, little information is available regarding the use of alternative extraction technologies, such as ultrasound. In this paper, ultrasound-assisted extraction (UAE) parameters, such as the liquid:solid ratio, solvent concentration and extraction time, were studied using response surface methodology (RSM) for the extraction of polyphenols from desert plants including Jatrophadioica,Flourensiacernua, Turneradiffusa and Eucalyptuscamaldulensis. Key process variables (i.e., liquid:solid ratio and ethanol concentration) exert the greatest influence on the extraction of all of the phenolic compounds (TPC) in the studied plants. The best conditions for the extraction of TPC involved an extraction time of 40min, an ethanol concentration of 35% and a liquid:solid ratio ranging from 8 to 12mlg(-1) depending on the plant. The highest antioxidant activity was obtained in the E. camaldulensis extracts. The results indicated the ability of UAE to obtain polyphenolic antioxidant preparations from desert plants. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Diel Behavioral Activity Patterns in Adult Solitarious Desert Locust, Schistocerca gregaria (Forskål

    Directory of Open Access Journals (Sweden)

    Sidi Ould Ely

    2011-01-01

    Full Text Available The responses of adult solitarious desert locust to odors from a host plant were evaluated in a two-choice wind tunnel. Solitarious desert locusts collected from the field (Red Sea Coast were more attracted to volatiles from potted Heliotropium ovalifolium in scotophase than in photophase. The attraction towards the host plant odors rather than to clean air, in both photophase and scotophase, concurs with previous observations on oviposition preferences near these plants. Diel behavioral activity patterns of adult solitarious desert locusts Schistocerca gregaria (Forskål that were collected from the field in Port Sudan were investigated by monitoring, scanning, resting, taking off, and walking/running in a wind tunnel. Solitarious locusts that had been propagated in the laboratory for 20 generations were also observed for comparison. In both groups of locusts, insects were significantly more active after sunset and this activity attained peak level at 1-2 hours after dusk. Of the two groups, solitarious locusts collected from the field were significantly more active. In the scotophase, the former traversed distances that were about seven times those covered by laboratory-reared locusts. Overall, the results show that the repertoire of behavioral activities of solitarious locusts is maintained in laboratory-reared insects, albeit at a lower level. The implications of these observations in the behavioral ecology of the desert locust are discussed.

  10. The Great Gatsby en The Diamont as Big as the Ritz

    NARCIS (Netherlands)

    Scott Fitzgerald, F.

    2005-01-01

    The Great Gatsby has long been celebrated as the archetypal American novel, and its influence on later writers from J.D. Salinger to John OHara cannot be overestimated. Fitzgerald looks deeply into himself and his milieu to create the story of James Gatz, a self-educated nobody from Kentucky who has

  11. The potential of energy farming in the southeastern California desert

    Science.gov (United States)

    Lew, V.

    1980-04-01

    The use of energy forms to provide future sources of energy for California is considered. Marginal desert lands in southeastern California are proposed for the siting of energy farms using acacia, eucalyptus, euphorbia, guayule, jojoba, mesquite, or tamarisk.

  12. HOW MUCH CARBON IS STORED IN DESERTS? AN APPROACH FOR THE CHILEAN ATACAMA DESERT USING LANDSAT-8 PRODUCTS

    Directory of Open Access Journals (Sweden)

    H. J. Hernández

    2016-06-01

    Full Text Available The Atacama Desert in northern Chile is known as the driest place on Earth, with an average rainfall of about 15 mm per year. Despite these conditions, it contains a rich variety of flora with hundreds of species characterised by their extraordinary ability to adapt to this extreme environment. These biotic components have a direct link to important ecosystem services, especially those related to carbon storage and sequestration. No quantitative assessment is currently available for these services and the role of the desert in this matter remains unclear. We propose an approach to estimate above-ground biomass (AGB using Landsat-8 data, which we tested in the Taparacá region, located in the northern section of the desert. To calibrate and validate the models, we used field data from 86 plots and several spectral indexes (NDVI, EVI and SAVI obtained from the provisional Landsat-8 Surface-reflectance products. We applied randomised branch sampling and allometry principles (non-destructive methods to collect biomass samples for all plant biological types: wetlands, steppes, shrubs and trees. All samples were dried in an oven until they reached constant weight and the final values were used to extrapolate dry matter content (AGB to each plot in terms of kg m-2. We used all available scenes from September 2014 to August 2015 to calculate the maximum, minimum and average value for each index in each pixel within this period. For modeling, we used the method based on classification and regression trees called random forest (RF, available in the statistical software R-Project. The explained variance obtained by the RF algorithm was around 80-85%, and it improved when a wetland vector layer was used as the predictive factor in the model to reach the range 85-90%. The mean error was 1.45 kg m-2 of dry matter. The best model was obtained using the maximum and mean values of SAVI and EVI indexes. We were able to estimate total biomass storage of around 8

  13. The great depression in Argentina, Brazil and Uruguay : revisiting vulnerabilities and policies

    NARCIS (Netherlands)

    Gerona Morales, Marcelo Esteban; Sosa Clavijo, Silvana Maria

    2015-01-01

    In this thesis Marcelo Gerona and Silvana Sosa undertake an analysis of the Great Depression (1928-1934) in a sample of three highly interconnected South American countries: Argentina, Brazil and Uruguay (ABU). The problem tackled in this work is the relative vulnerabilities of ABU, which

  14. Contrasting water use pattern of introduced and native plants in an alpine desert ecosystem, Northeast Qinghai–Tibet Plateau, China

    International Nuclear Information System (INIS)

    Wu, Huawu; Li, Xiao-Yan; Jiang, Zhiyun; Chen, Huiying; Zhang, Cicheng; Xiao, Xiong

    2016-01-01

    Plant water use patterns reflect the complex interactions between different functional types and environmental conditions in water-limited ecosystems. However, the mechanisms underlying the water use patterns of plants in the alpine desert of the Qinghai–Tibet Plateau remain poorly understood. This study investigated seasonal variations in the water sources of herbs (Carex moorcroftii, Astragalus adsurgens) and shrubs (Artemisia oxycephala, Hippophae rhamnoides) using stable oxygen-18 isotope methods. The results indicated that the native herbs (C. moorcroftii, A. adsurgens) and one of the shrubs (A. oxycephala) mainly relied on water from the shallow layer (0–30 cm) throughout the growing season, while the introduced shrub (H. rhamnoides) showed plasticity in switching between water from shallow and deep soil layers depending on soil water availability. All studied plants primarily depended on water from shallow soil layers early in the season. The differences of water use patterns between the introduced and native plants are closely linked with the range of active root zones when competing for water. Our findings will facilitate the mechanistic understanding of plant–soil–water relations in alpine desert ecosystems and provide information for screening introduced species for sand fixation. - Highlights: • Stable oxygen-18 in soil water experienced great evaporation enrichment. • H. rhamnoides experiences a flexible plasticity to switch between shallow and deep soil water. • Native plants mostly relied on shallow and middle soil water. • Water-use patterns by introduced-native plants are controlled by root characteristics.

  15. Probing the desert by the two-loop renormalization-group equations

    International Nuclear Information System (INIS)

    Tanimoto, M.; Suetake, Y.; Senba, K.

    1987-01-01

    We have reexamined the study of probing the desert with fermion masses, presented by Bagger, Dimopoulos, and Masso, by using the two-loop renormalization-group equations in the framework of the SU(3) x SU(2) x U(1) model with three generations and one Higgs doublet. The blow-up energy scale of the Yukawa coupling is found to be dependent on the Higgs quartic coupling λ. If the Yukawa coupling blows up between the electroweak scale M/sub W/ and the grand unified scale M/sub X/, the Higgs potential is destabilized for small values of λ at the electroweak scale M/sub W/, and becomes strongly coupled for large values of λ at M/sub W/. It is found that the Higgs-scalar mass as well as the fermion masses are important to probe the desert

  16. Analysis of "The Wonderful Desert." Technical Report No. 170.

    Science.gov (United States)

    Green, G. M.; And Others

    This report presents a text analysis of "The Wonderful Desert," a brief selection from the "Reader's Digest Skill Builder" series. (The techniques used in arriving at the analysis are presented in a Reading Center Technical Report, Number 168, "Problems and Techniques of Text Analysis.") Tables are given for a…

  17. Ecology and utilization of desert shrub rangelands in Iraq

    NARCIS (Netherlands)

    Thalen, Derk Catharinus Peter

    1979-01-01

    When grazing is the accepted land use, vegetation is the key resource. The present study deals with the desert shrub rangelands of lraq, which contain the major characteristics of such an area, having been under grazing for many centuries. Emphasis is given to the ecology and utilization of the

  18. The case of Montréal's missing food deserts: Evaluation of accessibility to food supermarkets

    Directory of Open Access Journals (Sweden)

    Cloutier Marie-Soleil

    2007-02-01

    Full Text Available Abstract Background Access to varied, healthy and inexpensive foods is an important public health concern that has been widely documented. Consequently, there is an increasing interest in identifying food deserts, that is, socially deprived areas within cities that have poor access to food retailers. In this paper we propose a methodology based on three measures of accessibility to supermarkets calculated using geographic information systems (GIS, and on exploratory multivariate statistical analysis (hierarchical cluster analysis, which we use to identify food deserts in Montréal. Results First, the use of three measures of accessibility to supermarkets is very helpful in identifying food deserts according to several dimensions: proximity (distance to the nearest supermarket, diversity (number of supermarkets within a distance of less than 1000 metres and variety in terms of food and prices (average distance to the three closest different chain-name supermarkets. Next, the cluster analysis applied to the three measures of accessibility to supermarkets and to a social deprivation index demonstrates that there are very few problematic food deserts in Montréal. In fact, census tracts classified as socially deprived and with low accessibility to supermarkets are, on average, 816 metres away from the nearest supermarket and within 1.34 kilometres of three different chain-name supermarkets. Conclusion We conclude that food deserts do not represent a major problem in Montréal. Since geographic accessibility to healthy food is not a major issue in Montréal, prevention efforts should be directed toward the understanding of other mechanisms leading to an unhealthy diet, rather than attempting to promote an even spatial distribution of supermarkets.

  19. The relative abundance of desert tortoises on the Nevada Test Site within ecological landform units

    International Nuclear Information System (INIS)

    Woodward, R.; Rautenstrauch, K.R.; Hall, D.B.; Ostler, W.K.

    1998-09-01

    Sign-survey transects were sampled in 1996 to better determine the relative abundance of desert tortoises on the Nevada Test Site (NTS). These transects were sampled within ecological land-form units (ELUs), which are small, ecologically homogeneous units of land. Two-hundred and six ELUs were sampled by walking 332 transects totaling 889 kilometers (km). These ELUs covered 528 km 2 . Two-hundred and eight-one sign were counted. An average of 0.32 sign was found per km walked. Seventy percent of the area sampled had a very low abundance of tortoises, 29% had a low abundance, and 1% had a moderate abundance. A revised map of the relative abundance of desert tortoise on the NTS is presented. Within the 1,330 km 2 of desert tortoise habitat on the NTS, 49% is classified as having no tortoises or a very low abundance, 18% has a low or moderate abundance, 12% is unclassified land being used by the Yucca Mountain Site Characterization Project, and the remaining 21% still has an unknown abundance of desert tortoises. Based on the results of this work, the amount of tortoise habitat previously classified as having an unknown or low-moderate abundance, and on which clearance surveys and on-site monitoring was required, has been reduced by 20%

  20. Hydrological indications of aeolian salts in mid-latitude deserts of ...

    Indian Academy of Sciences (India)

    soils in low-latitude deserts, but is less common in the aeolian sediments from the ... indicating the chemistry of aeolian salts and the associated parent brines may ... erosion, deposition and other processes on sediment properties will bias the ...

  1. American Studies

    Directory of Open Access Journals (Sweden)

    V. O. Pechatnov

    2014-01-01

    Full Text Available The "Founding fathers" of American Studies at MGIMO are considered to be A.V. Efimov and L.I. Clove. Alexey Efimov - Corresponding Member of the USSR Academy of Sciences since 1938, Head of the Department of Modern and Contemporary History and Dean of the Historical School at the Moscow State University - one of the first professors of the Faculty of International Relations MGIMO. Efimov distinguished himself by a broad vision and scope of scientific interests. Back in 1934 he published a monograph "On the history of capitalism in the United States," which initiated a series of research culminating in the fundamental work "The United States. The path of capitalist development (pre-imperialist era". Alexey was not only a great scientist but also a great teacher, whose lectures was popular throughout Moscow. His lecture courses, given at the end of the 1940s at MGIMO, became the basis for the first post-war history textbooks USA - "Essays on the history of the United States." At least as colorful a figure was Professor Leo Izrailevich Zubok - a man of unusual destiny. As a teenager he emigrated to the United States with his parents, where he soon joined the American revolutionary movement in the 1920s and was forced to leave the country. He came to MGIMO being already an experienced scientists. His research interests were very wide: from the study of American foreign policy expansion to the history of the labor movement in the United States. Zubok's fundamental works still have not lost its scientific significance. He has successfully combined scientific work with teaching. Tutorials that are based on his lectures were very popular not only among students of MGIMO.

  2. Effect of water stress on in vitro mycelium cultures of two mycorrhizal desert truffles.

    Science.gov (United States)

    Navarro-Ródenas, Alfonso; Lozano-Carrillo, M Cecilia; Pérez-Gilabert, Manuela; Morte, Asunción

    2011-05-01

    The ability of two species of desert truffle, Terfezia claveryi strain TcS2 and Picoa lefebvrei strain OL2, to tolerate water stress in pure culture has been investigated. Both T. claveryi and P. lefebvrei strains exhibited a mycelium growth pattern characteristic of drought tolerant species. However, they were only tolerant to moderate water stress, below -1.07 MPa, with the P. lefebvrei isolate being slightly more drought tolerant than the T. claveryi isolate. The increased alkaline phosphatase (ALP) activity observed in both fungi at moderate water stress with respect to the control indicated the functional adaptation of these mycelia to these drought conditions. ALP activity can be used as an indicator of the metabolic activity of these fungi. Slight water stress (-0.45 MPa) could improve mycelial inoculum production of these desert truffles. Moreover, P. lefebvrei could be a good candidate for further desert truffle mycorrhizal plant cultivation programmes in semiarid Mediterranean areas.

  3. The different influence of the residual layer on the development of the summer convective boundary layer in two deserts in northwest China

    Science.gov (United States)

    Lin, Zhao; Bo, Han; Shihua, Lv; Lijuan, Wen; Xianhong, Meng; Zhaoguo, Li

    2018-02-01

    The development of the atmospheric boundary layer is closely connected with the exchange of momentum, heat, and mass near the Earth's surface, especially for a convective boundary layer (CBL). Besides being modulated by the buoyancy flux near the Earth's surface, some studies point out that a neutrally stratified residual layer is also crucial for the appearance of a deep CBL. To verify the importance of the residual layer, the CBLs over two deserts in northwest China (Badan Jaran and Taklimakan) were investigated. The summer CBL mean depth over the Taklimakan Desert is shallower than that over the Badan Jaran Desert, even when the sensible heat flux of the former is stronger. Meanwhile, the climatological mean residual layer in the Badan Jaran Desert is much deeper and neutrally stratified in summer. Moreover, we found a significant and negative correlation between the lapse rate of the residual layer and the CBL depth over the Badan Jaran Desert. The different lapse rates of the residual layer in the two regions are partly connected with the advection heating from large-scale atmospheric circulation. The advection heating tends to reduce the temperature difference in the 700 to 500-hPa layer over the Badan Jaran Desert, and it increases the stability in the same atmospheric layer over the Taklimakan Desert. The advection due to climatological mean atmospheric circulation is more effective at modulating the lapse rate of the residual layer than from varied circulation. Also, the interannual variation of planetary boundary layer (PBL) height over two deserts was found to covary with the wave train.

  4. Joint by Design: The Western Desert Campaign

    Science.gov (United States)

    2015-05-21

    Introduction Seated in a dusty tent, finally cooling in the Egyptian night, the “Desert Fox” had a serious problem. German Lieutenant General Erwin...Complexity: A Platform for Designing Business Architecture , 2nd ed. (Amsterdam: Elsevier, 2006), 30-32. 65 Lewin, Montgomery, 121. 29 Allies...Benghazi and Tobruk, and the Egyptian port of Matruh were operating at 60 percent of their potential capacity. By the end of August, the Axis loss rate of

  5. Extrafloral nectar fuels ant life in deserts

    OpenAIRE

    Aranda-Rickert, Adriana; Diez, Patricia; Marazzi, Brigitte

    2014-01-01

    Interactions mediated by extrafloral nectary (EFN)-bearing plants that reward ants with a sweet liquid secretion are well documented in temperate and tropical habitats. However, their distribution and abundance in deserts are poorly known. In this study, we test the predictions that biotic interactions between EFN plants and ants are abundant and common also in arid communities and that EFNs are only functional when new vegetative and reproductive structures are developing. In a seasonal dese...

  6. Relationship Between Job Burnout and Neuroendocrine Indicators in Soldiers in the Xinjiang Arid Desert: A Cross-Sectional Study

    Directory of Open Access Journals (Sweden)

    Ning Tao

    2015-12-01

    Full Text Available The purpose of this study was to explore the relationship between job burnout and neuroendocrine indicators in soldiers living in a harsh environment. Three hundred soldiers stationed in the arid desert and 600 in an urban area were recruited. They filled in the Chinese Maslach Burnout Inventory questionnaire. One hundred soldiers were randomly selected from each group to measure their levels of noradrenaline, serotonin, heat shock protein (HSP-70, adrenocorticotropic hormone, and serum cortisol. Job burnout was more common in soldiers from urban areas than those from rural areas. Job burnout was significantly higher among soldiers stationed in the arid desert than those in urban areas. For soldiers in the arid desert, the levels of HSP-70, serum cortisol, and adrenocorticotropic hormone were significantly higher than in soldiers in urban areas. Correlation analyses showed that the degree of job burnout was weakly negatively correlated with the level of HSP-70. Being an only child, HSP-70 levels, cortisol levels, and ACTH levels were independently associated with job burnout in soldiers stationed in the arid desert. A higher level of job burnout in soldiers stationed in arid desert and a corresponding change in neuroendocrine indicators indicated a correlation between occupational stress and neurotransmitters.

  7. Effect of Atmospheric Conditions on Coverage of Fogger Applications in a Desert Surface Boundary Layer

    Science.gov (United States)

    2012-01-01

    Salyani, T. W. Walker, M. Farooq ABSTRACT. Near-ground aerosol fogs were applied in the Chihuahua Desert of New Mexico, which has widely spaced, low...Approved for public release; distribution unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Near-ground aerosol fogs were applied in the Chihuahua Desert of...1.6° surrounded by sparse Chihuahua De- sert vegetation approximately 2 m tall (fig. 1). The vegeta- tion was primarily mesquite and creosote bushes

  8. Structure and function of the mammalian middle ear. I: Large middle ears in small desert mammals.

    Science.gov (United States)

    Mason, Matthew J

    2016-02-01

    Many species of small desert mammals are known to have expanded auditory bullae. The ears of gerbils and heteromyids have been well described, but much less is known about the middle ear anatomy of other desert mammals. In this study, the middle ears of three gerbils (Meriones, Desmodillus and Gerbillurus), two jerboas (Jaculus) and two sengis (elephant-shrews: Macroscelides and Elephantulus) were examined and compared, using micro-computed tomography and light microscopy. Middle ear cavity expansion has occurred in members of all three groups, apparently in association with an essentially 'freely mobile' ossicular morphology and the development of bony tubes for the middle ear arteries. Cavity expansion can occur in different ways, resulting in different subcavity patterns even between different species of gerbils. Having enlarged middle ear cavities aids low-frequency audition, and several adaptive advantages of low-frequency hearing to small desert mammals have been proposed. However, while Macroscelides was found here to have middle ear cavities so large that together they exceed brain volume, the bullae of Elephantulus are considerably smaller. Why middle ear cavities are enlarged in some desert species but not others remains unclear, but it may relate to microhabitat. © 2015 Anatomical Society.

  9. Variation of Desert Soil Hydraulic Properties with Pedogenic Maturity

    Science.gov (United States)

    Nimmo, J. R.; Perkins, K. S.; Mirus, B. B.; Schmidt, K. M.; Miller, D. M.; Stock, J. D.; Singha, K.

    2006-12-01

    Older alluvial desert soils exhibit greater pedogenic maturity, having more distinct desert pavements, vesicular (Av) horizons, and more pronounced stratification from processes such as illuviation and salt accumulation. These and related effects strongly influence the soil hydraulic properties. Older soils have been observed to have lower saturated hydraulic conductivity, and possibly greater capacity to retain water, but the quantitative effect of specific pedogenic features on the soil water retention or unsaturated hydraulic conductivity (K) curves is poorly known. With field infiltration/redistribution experiments on three different-aged soils developed within alluvial wash deposits in the Mojave National Preserve, we evaluated effective hydraulic properties over a scale of several m horizontally and to 1.5 m depth. We then correlated these properties with pedogenic features. The selected soils are (1) recently deposited sediments, (2) a soil of early Holocene age, and (3) a highly developed soil of late Pleistocene age. In each experiment we ponded water in a 1-m-diameter infiltration ring for 2.3 hr. For several weeks we monitored subsurface water content and matric pressure using surface electrical resistance imaging, dielectric-constant probes, heat-dissipation probes, and tensiometers. Analysis of these data using an inverse modeling technique gives the water retention and K properties needed for predictive modeling. Some properties show a consistent trend with soil age. Progressively more developed surface and near-surface features such as desert pavement and Av horizons are the likely cause of an observed consistent decline of infiltration capacity with soil age. Other properties, such as vertical flow retardation by layer contrasts, appear to have a more complicated soil-age dependence. The wash deposits display distinct depositional layering that has a retarding effect on vertical flow, an effect that may be less pronounced in the older Holocene soil

  10. The Ill-Structured Militia Problem in Africa’s Great Lakes Region

    Science.gov (United States)

    2013-03-01

    includes the Lord’s Resistance Army (LRA), the Allied Democratic Forces, Peoples Redemption Army,1 Armed Forces of Congo (FAC), Union des Patriotes...LRA bases inside Sudan. As a result, the UPDF launched a massive military offensive code named Operation Iron Fist.16 The Sudanese government was...former CNDP combatants from Kivu to other provinces. Ntaganda deserted from the FARDC with 300 soldiers.36 This opened the way for massive desertions

  11. [Spatial variation of soil carbon and stable isotopes in the southern margin desert of Junggar Basin, China].

    Science.gov (United States)

    Wang, Na; Xu, Wen Qiang; Xu, Hua Jun; Feng, Yi Xing; Li, Chao Fan

    2017-07-18

    The southern margin desert of Junggar Basin in the central arid region of Asia was selec-ted as the study area. To gain insight into the distribution characteristic of stable carbon isotope and the relationship between the change of soil carbon and the distance to oasis of soil organic carbon (SOC) and soil inorganic carbon (SIC), three belt transects were set according to the distance between the desert and the oasis in edge, middle and hinterland of the desert respectively, and collected the soil profile samples with depth of 2 m. The results indicated that the SOC content reduced with the soil depth, and the variation with the distance to oasis was the edge> the middle> the hinterland. The δ 13 C value of SOC varied in the range of -21.92‰ to -17.41‰, and decreased with the depth; the range in the middle and hinterland was -25.20‰ to -19.30‰, and increased then declined with the depth. Therefore, we could infer that the C3 plants played a dominant role in the central of desert, and had experienced the succession from C3 plants to C4 plants. The average content of SIC was 38.98 g·kg -1 in the edge of desert, which was about 6.01 folds as large as the content in the hinterland. This indicated that a large number of SIC with 0-2 m depth were clustered in the edge of the desert. The δ 13 C value of SIC increased first then decreased with the soil depth, and enriched in the bottom layer, which was mainly affected by the original carbonate content and soil carbon dioxide.

  12. Bringing China In: International Order and the Role of the Great Powers

    Science.gov (United States)

    2013-06-01

    powers. Can China Learn to Behave Like a Great Power: Spoiler, Supporter or Shirker? Realists generally contend that a structural transformation from...abandonment of American values, but for a distinction between the realizable and the absolute.”33 When Washington and Beijing ruminate on how to

  13. Distribution and status of the desert-dwelling giraffe ( Giraffa ...

    African Journals Online (AJOL)

    The population density and distribution of desert dwelling giraffes was estimated in three study areas in the Hoanib River catchment, northwestern Namibia. Giraffe population densities (0.01 giraffe/km2) were equal to the lowest recorded in Africa with population numbers fluctuating over past decades. Sex ratios, herd sizes ...

  14. Isotopic and hydrochemical evidence of groundwater recharge in the Hopq Desert, NW China

    International Nuclear Information System (INIS)

    Jian Ge; Tao Wang; Yafei Chen; Jiansheng Chen; Hohai University, Nanjing, Jiangsu Province; Lu Ge; Chao Wang

    2016-01-01

    Artesian wells and lakes are found in the hinterland of the Hopq Desert, China. Analysis of soil profiles has revealed that the local vadose zone is always in a state of water deficit because of strong evaporation, and precipitation cannot infiltrate into the groundwater. This research indicated that soil water and surface water are recharged by groundwater and that the groundwater is recharged via an external source. Analyses of the stable isotopes in precipitation and of the water budget suggested that surface water in the Qiangtang Basin on the Tibetan Plateau might correspond to the groundwater in the Hopq Desert. (author)

  15. diurnal and seasonal water relations of the desert phreatophyte prosopis-glandulosa (honey mesquite) in the Sonoran Desert of California

    OpenAIRE

    Nilsen, E. T.; Sharifi, M. R.; Rundel, P. W.; Jarrell, W. M.; Virginia, R. A.

    1983-01-01

    Diurnal and Seasonal water relations were monitored in a population of Prosopis glandulosa var. torreyana in the Sonoran Desert of southern California. Prosopis glandulosa at this research site acquired its water from a ground water source 4-6 m deep. Measurements of diurnal and seasonal cycles of aboveground environmental conditions, soil moisture, and soil water potential (to 6 m depth) were taken to ascertain environmental water availability and water stress. Leaf water potential, leaf con...

  16. Multiple factors affect a population of Agassiz's desert tortoise (Gopherus agassizii) in the Northwestern Mojave Desert

    Science.gov (United States)

    Berry, Kristin H.; Yee, Julie L.; Coble, Ashley A.; Perry, William M.; Shields, Timothy A.

    2013-01-01

    Numerous factors have contributed to declines in populations of the federally threatened Agassiz's Desert Tortoise (Gopherus agassizii) and continue to limit recovery. In 2010, we surveyed a low-density population on a military test facility in the northwestern Mojave Desert of California, USA, to evaluate population status and identify potential factors contributing to distribution and low densities. Estimated densities of live tortoises ranged spatially from 1.2/km2 to 15.1/km2. Although only one death of a breeding-age tortoise was recorded for the 4-yr period prior to the survey, remains of 16 juvenile and immature tortoises were found, and most showed signs of predation by Common Ravens (Corvus corax) and mammals. Predation may have limited recruitment of young tortoises into the adult size classes. To evaluate the relative importance of different types of impacts to tortoises, we developed predictive models for spatially explicit densities of tortoise sign and live tortoises using topography (i.e., slope), predators (Common Raven, signs of mammalian predators), and anthropogenic impacts (distances from paved road and denuded areas, density of ordnance fragments) as covariates. Models suggest that densities of tortoise sign increased with slope and signs of mammalian predators and decreased with Common Ravens, while also varying based on interaction effects involving these predictors as well as distances from paved roads, denuded areas, and ordnance. Similarly, densities of live tortoises varied by interaction effects among distances to denuded areas and paved roads, density of ordnance fragments, and slope. Thus multiple factors predict the densities and distribution of this population.

  17. Soil texture drives responses of soil respiration to precipitation pulses in the sonoran desert: Implications for climate change

    Science.gov (United States)

    Cable, J.M.; Ogle, K.; Williams, D.G.; Weltzin, J.F.; Huxman, T. E.

    2008-01-01

    Climate change predictions for the desert southwestern U.S. are for shifts in precipitation patterns. The impacts of climate change may be significant, because desert soil processes are strongly controlled by precipitation inputs ('pulses') via their effect on soil water availability. This study examined the response of soil respiration-an important biological process that affects soil carbon (C) storage-to variation in pulses representative of climate change scenarios for the Sonoran Desert. Because deserts are mosaics of different plant cover types and soil textures-which create patchiness in soil respiration-we examined how these landscape characteristics interact to affect the response of soil respiration to pulses. Pulses were applied to experimental plots of bare and vegetated soil on contrasting soil textures typical of Sonoran Desert grasslands. The data were analyzed within a Bayesian framework to: (1) determine pulse size and antecedent moisture (soil moisture prior to the pulse) effects on soil respiration, (2) quantify soil texture (coarse vs. fine) and cover type (bare vs. vegetated) effects on the response of soil respiration and its components (plant vs. microbial) to pulses, and (3) explore the relationship between long-term variation in pulse regimes and seasonal soil respiration. Regarding objective (1), larger pulses resulted in higher respiration rates, particularly from vegetated fine-textured soil, and dry antecedent conditions amplified respiration responses to pulses (wet antecedent conditions dampened the pulse response). Regarding (2), autotrophic (plant) activity was a significant source (???60%) of respiration and was more sensitive to pulses on coarse- versus fine-textured soils. The sensitivity of heterotrophic (microbial) respiration to pulses was highly dependent on antecedent soil water. Regarding (3), seasonal soil respiration was predicted to increase with both growing season precipitation and mean pulse size (but only for pulses

  18. Tall Tales: The Simpsons deconstructing the american myth

    Directory of Open Access Journals (Sweden)

    Hanna Betina Götz

    2014-07-01

    Full Text Available This article aims to analyze the episode Tall Tales from the series The Simpsons that revisits legends of the American folklore. The TV series pays homage to both the time of the pioneers in their travels to the Far West in the nineteenth century, as well as to one of the most iconic and folk characters of the American culture from that period: the Hobo was a beggar, a figure of the American folklore during the Great Depression. It is also interesting to focus on the American imaginary in order to understand how the authors of The Simpsons perform these recreations in contemporary times

  19. Epidemiology and clinical presentation of stroke in Upper Egypt (desert area

    Directory of Open Access Journals (Sweden)

    El Tallawy HN

    2015-08-01

    Full Text Available Hamdy N El Tallawy,1 Wafaa M Farghaly,1 Reda Badry,1 Nermin A Hamdy,2 Ghaydaa A Shehata,1 Tarek A Rageh,1 Nabil A Metwally,3 Enas M Hassan,2 Sayed S Elsayed,2 Mohamed A Yehia,2 Wael T Soliman2 1Department of Neurology and Psychiatry, Assiut University, Assiut, 2Department of Neurology, El Minia University, El-Minia City, 3Department of Neurology, Al-Azhar University (Assuit Branch, Assiut, Egypt Background: Stroke is a common cause of morbidity and mortality worldwide. Four out of five strokes occur in the low- and middle-income countries. This study aims to find lifetime prevalence of stroke in Upper Egypt and to identify clinical presentations and possible risk factors of stroke in this population.Methods: This is a door-to-door (every door study conducted on all inhabitants in Al Kharga district (representative of western desert and Al Quseir city (representative of eastern desert. The study was conducted in two stages, and every stage consisted of three phases (screening, diagnostic, and investigatory.Results: The total lifetime prevalence of stroke was 8.5/1,000 in the population aged 20 years and more. It increased with advancing age and was higher among males than females among all age groups except in the childbearing period (20 years to <40 years of age. Lifetime prevalence of ischemic stroke (7.2/1,000 was higher than hemorrhagic stroke (1.1/1,000. Hemiparesis and hemiplegia were the commonest presentation of stroke. Headache, vomiting, and vertigo were found to be significantly more common accompaniments of hemorrhagic stroke. The most common risk factor was hypertension, followed by hyperlipidemia and diabetes mellitus.Conclusion: The total lifetime prevalence of stroke in the population aged 20 years and more in Upper Egypt (desert area lies within the range that is recorded in developing countries. Clinical presentation and risk factors are similar to those recorded from developing and developed countries. Keywords: stroke

  20. The effects of drying following heat shock exposure of the desert moss Syntrichia caninervis.

    Science.gov (United States)

    Xu, Shu-Jun; Liu, Chun-Jiang; Jiang, Ping-An; Cai, Wei-Min; Wang, Yan

    2009-03-15

    Desert mosses are components of biological soil crusts (BSCs) and their ecological functions make assessment and protection of these mosses a high-ranking management priority in desert regions. Drying is thought to be useful for desert mosses surviving heat shock. In this study, we investigated the role of drying by monitoring the responses of physiological characters and asexual reproduction in the typical desert moss Syntrichia caninervis. Heat significantly decreased chlorophyll content and weakened rapid recovery of photochemical activity, and increased carotenoid content and membrane permeability. Lethal temperatures significantly destroyed shoot regeneration potential. In comparison with heat alone, drying significantly increased protonema emergence time and depressed protonema emergence area. Drying combined with heat accelerated water loss, followed by a decrease of photosynthetic activity. Drying had different influences on membrane permeability at different temperatures. When moss leaves were subjected to a combined stress of drying and heat shock, photosynthesis was maintained mainly due to the effects of drying on physiological activity although the cellular morphological integrity was affected. Drying caused opposing effects on moss physiological and reproductive characteristics. On the one hand, drying caused a positive synergistic effect with heat shock when the temperature was below 40 degrees C. On the other hand, drying showed antagonism with heat shock when the moss was subjected to temperatures higher than 40 degrees C. These findings may help in understanding the survival mechanism of dessert mosses under heat shock stress which will be helpful for the artificial reconstruction of BSCs.