2,279 research outputs found

    Blowout morphometrics and mass balances

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    The Gonghe Basin on the Qinghai-Tibet Plateau has a cold, arid climate and has suffered severe land degradation. Climate change as well as anthropogenic activities including overgrazing have resulted in widespread blowout development and the formation of some of Earth's largest blowouts. The blowouts are part of an aeolian dominated landscape that passes from deflation zone to grass covered plain, and then through blowouts of increasing size and complexity to transverse barchanoid dunes that are migrating into the valley of the Yellow River. A combination of structure-from-motion (SfM) optical drone mapping, ground-penetrating radar (GPR) and soil pits are used to investigate blowout scour hollows and depositional lobes. Comparisons of the volumes of sediment removed from the scour hollows with the volumes of sediment deposited within adjacent lobes varies between sites. The lobe volume is invariably less than the volume of the scour hollow. This can, in part, be attributed to aeolian reworking of the lobe, distributing sand further downwind and uplifting of dust. However, much of the difference in volumes between the scour and lobe can be attributed to the measurement technique, particularly where GPR was employed to calculate lobe volumes. The wavelength of the GPR limits its ability to resolve thin layers of sand resulting in an underestimate of the deposited sand at the margins of a lobe where the sand thickness is equal to, or less than, the wavelength of the GPR. For thin sand layers, beneath the resolution of the GPR, soil pits suggest a closer match between the volume of sand eroded from the scour and the volume of the lobe, albeit with large measurement uncertainty. We put forth two hypotheses to explain the spatio-temporal evolution of the blowout dune field. The downwind increase in blowout dune size could either reflect a downwind propagation of aeolian instability; or it could result from an upwind propagation of the instability, which started at the highest points in the landscape and has subsequently migrated in a northwesterly direction, towards lower elevations. Recent optically stimulated luminescence dating appear to support the latter hypothesis

    "On the Spot": travelling artists and Abolitionism, 1770-1830

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    Until recently the visual culture of Atlantic slavery has rarely been critically scrutinised. Yet in the first decades of the nineteenth century slavery was frequently represented by European travelling artists, often in the most graphic, sometimes voyeuristic, detail. This paper examines the work of several itinerant artists, in particular Augustus Earle (1793-1838) and Agostino Brunias (1730–1796), whose very mobility along the edges of empire was part of a much larger circulatory system of exchange (people, goods and ideas) and diplomacy that characterised Europe’s Age of Expansion. It focuses on the role of the travelling artist, and visual culture more generally, in the development of British abolitionism between 1770 and 1830. It discusses the broad circulation of slave imagery within European culture and argues for greater recognition of the role of such imagery in the abolitionist debates that divided Britain. Furthermore, it suggests that the epistemological authority conferred on the travelling artist—the quintessential eyewitness—was key to the rhetorical power of his (rarely her) images. Artists such as Earle viewed the New World as a boundless source of fresh material that could potentially propel them to fame and fortune. Johann Moritz Rugendas (1802-1858), on the other hand, was conscious of contributing to a global scientific mission, a Humboldtian imperative that by the 1820s propelled him and others to travel beyond the traditional itinerary of the Grand Tour. Some artists were implicated in the very fabric of slavery itself, particularly those in the British West Indies such as William Clark (working 1820s) and Richard Bridgens (1785-1846); others, particularly those in Brazil, expressed strong abolitionist sentiments. Fuelled by evangelical zeal to record all aspects of the New World, these artists recognised the importance of representing the harsh realities of slave life. Unlike those in the metropole who depicted slavery (most often in caustic satirical drawings), many travelling artists believed strongly in the evidential value of their images, a value attributed to their global mobility. The paper examines the varied and complex means by which visual culture played a significant and often overlooked role in the political struggles that beset the period

    Seismic interpretation of pelagic sedimentation regimes in the 18–53 Ma eastern equatorial Pacific : basin-scale sedimentation and infilling of abyssal valleys

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    Author Posting. © American Geophysical Union, 2011. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 12 (2011): Q03004, doi:10.1029/2010GC003347.Understanding how pelagic sediment has been eroded, transported, and deposited is critical to evaluating pelagic sediment records for paleoceanography. We use digital seismic reflection data from an Integrated Ocean Drilling Program site survey (AMAT03) to investigate pelagic sedimentation across the eastern-central equatorial Pacific, which represents the first comprehensive record published covering the 18–53 Ma eastern equatorial Pacific. Our goals are to quantify (1) basin-hill-scale primary deposition regimes and (2) the extent to which seafloor topography has been subdued by abyssal valley-filling sediments. The eastern Pacific seafloor consists of a series of abyssal hills and basins, with minor late stage faulting in the basement. Ocean crust rarely outcrops at the seafloor away from the rise crest; both hills and basins are sediment covered. The carbonate compensation depth is identified at 4440 m by the appearance of acoustically transparent clay intervals in the seismic data. Overall, we recognized three different sedimentation regimes: depositional (high sedimentation rate), transitional, and minimal sedimentation (low sedimentation rate) regimes. In all areas, the sedimented seafloor mimics the underlying basement topography, although the degree to which topography becomes subdued varies. Depositional regimes result in symmetric sedimentation within basins and subdued topography, whereas minimal sedimentation regimes have more asymmetric distribution of sediments within topographic lows and higher seafloor relief. Regardless of sedimentation regime, enhanced sediment deposition occurs within basins. However, we observe that basin infill is rarely more than twice as thick as sediment cover over abyssal hills. If this variation is due to sediment focusing, the focusing factor in the basins, as measured by 230Th, is no more than a factor of ∌1.3 of the total vertical particulate rain.This research is supported by NSF grants OCE‐07253011 and OCE‐0851056 (M. Lyle and M. Tominaga) and NERC grant NE/C508985/2 (N. C. Mitchell)

    Changes in circulating microRNA levels associated with prostate cancer

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    BACKGROUND: The aim of this study was to investigate the hypothesis that changes in circulating microRNAs (miRs) represent potentially useful biomarkers for the diagnosis, staging and prediction of outcome in prostate cancer. METHODS: Real-time polymerase chain reaction analysis of 742 miRs was performed using plasma-derived circulating microvesicles of 78 prostate cancer patients and 28 normal control individuals to identify differentially quantified miRs. RESULTS: A total of 12 miRs were differentially quantified in prostate cancer patients compared with controls, including 9 in patients without metastases. In all, 11 miRs were present in significantly greater amounts in prostate cancer patients with metastases compared with those without metastases. The association of miR-141 and miR-375 with metastatic prostate cancer was confirmed using serum-derived exosomes and microvesicles in a separate cohort of patients with recurrent or non-recurrent disease following radical prostatectomy. An analysis of five selected miRs in urine samples found that miR-107 and miR-574-3p were quantified at significantly higher concentrations in the urine of men with prostate cancer compared with controls. CONCLUSION: These observations suggest that changes in miR concentration in prostate cancer patients may be identified by analysing various body fluids. Moreover, circulating miRs may be used to diagnose and stage prostate cance

    Measurements of Six-Body Hadronic Decays of the D^0 Charmed Meson

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    Using data collected by the FOCUS experiment at Fermilab, we report the discovery of the decay modes D^0 --> K- pi+ pi+ pi+ pi- pi- and D^0 --> pi+ pi+ pi+ pi- pi- pi-. With a sample of 48 +/- 10 reconstructed D^0 --> K- pi+ pi+ pi+ pi- pi- decays and 149 +/- 17 reconstructed D^0 --> pi+ pi+ pi+ pi- pi- pi- decays, we measure the following relative branching ratios: Γ(D0→K−π+π+π+π−π−)/Γ(D0→K−π+π+π−)=(2.70±0.58±0.38)×10−3{\Gamma (D^0 \to K^- \pi^+ \pi^+ \pi^+ \pi^- \pi^-) / \Gamma (D^0 \to K^- \pi^+ \pi^+ \pi^-)} = (2.70 \pm 0.58 \pm 0.38) \times 10^{-3} Γ(D0→π+π+π+π−π−π−)/Γ(D0→K−π+π+π−)=(5.23±0.59±1.35)×10−3{\Gamma (D^0 \to \pi^+ \pi^+ \pi^+ \pi^- \pi^- \pi^-) / \Gamma (D^0 \to K^- \pi^+ \pi^+ \pi^-)} = (5.23 \pm 0.59 \pm 1.35) \times 10^{-3} Γ(D0→π+π+π+π−π−π−)/Γ(D0→K−π+π+π+π−π−)=1.93±0.47±0.48{\Gamma (D^0 \to \pi^+ \pi^+ \pi^+ \pi^- \pi^- \pi^-) / \Gamma (D^0 \to K^- \pi^+ \pi^+ \pi^+ \pi^- \pi^-)} = 1.93 \pm 0.47 \pm 0.48 The first errors are statistical and the second are systematic. The branching fraction of the Cabibbo suppressed six-body decay mode is measured to be a factor of two higher than the branching fraction of the Cabibbo favored six-body decay mode.Comment: To be submitted to Phys. Lett.

    GLACE: the global land–atmosphere coupling experiment. Part I: overview

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    Permission to place copies of these works on this server has been provided by the American Meteorological Society (AMS). The AMS does not guarantee that the copies provided here are accurate copies of the published work. © Copyright 2006 American Meteorological Society (AMS). Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108, as revised by P.L. 94-553) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form on servers, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. Additional details are provided in the AMS Copyright Policy, available on the AMS Web site located at (http://www.ametsoc.org/AMS) or from the AMS at 617-227-2425 or [email protected] Global Land–Atmosphere Coupling Experiment (GLACE) is a model intercomparison study focusing on a typically neglected yet critical element of numerical weather and climate modeling: land–atmosphere coupling strength, or the degree to which anomalies in land surface state (e.g., soil moisture) can affect rainfall generation and other atmospheric processes. The 12 AGCM groups participating in GLACE performed a series of simple numerical experiments that allow the objective quantification of this element for boreal summer. The derived coupling strengths vary widely. Some similarity, however, is found in the spatial patterns generated by the models, with enough similarity to pinpoint multimodel “hot spots” of land–atmosphere coupling. For boreal summer, such hot spots for precipitation and temperature are found over large regions of Africa, central North America, and India; a hot spot for temperature is also found over eastern China. The design of the GLACE simulations are described in full detail so that any interested modeling group can repeat them easily and thereby place their model’s coupling strength within the broad range of those documented here

    Measurement of the Ratio of the Vector to Pseudoscalar Charm Semileptonic Decay Rate \Gamma(D+ > ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)

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    Using a high statistics sample of photo-produced charm particles from the FOCUS experiment at Fermilab, we report on the measurement of the ratio of semileptonic rates \Gamma(D+ > ANTI-K pi mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.625 +/- 0.045 +/- 0.034. Allowing for the K pi S-wave interference measured previously by FOCUS, we extract the vector to pseudoscalar ratio \Gamma(D+ > ANTI-K*0 mu+ nu)/\Gamma(D+ > ANTI-K0 mu+ nu)= 0.594 +/- 0.043 +/- 0.033 and the ratio \Gamma(D+ > ANTI-K0 mu+ nu)/\Gamma(D+ > K- pi+ pi+)= 1.019 +/- 0.076 +/- 0.065. Our results show a lower ratio for \Gamma(D > K* \ell nu})/\Gamma(D > K \ell nu) than has been reported recently and indicate the current world average branching fractions for the decays D+ >ANTI-K0(mu+, e+) nu are low. Using the PDG world average for B(D+ > K- pi+ pi+) we extract B(D+ > ANIT-K0 mu+ nu)=(9.27 +/- 0.69 +/- 0.59 +/- 0.61)%.Comment: 15 pages, 1 figur

    Improving mental health and psychosocial wellbeing in humanitarian settings: Reflections on research funded through R2HC

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    From Springer Nature via Jisc Publications RouterMajor knowledge gaps remain concerning the most effective ways to address mental health and psychosocial needs of populations affected by humanitarian crises. The Research for Health in Humanitarian Crisis (R2HC) program aims to strengthen humanitarian health practice and policy through research. As a significant portion of R2HC’s research has focused on mental health and psychosocial support interventions, the program has been interested in strengthening a community of practice in this field. Following a meeting between grantees, we set out to provide an overview of the R2HC portfolio, and draw lessons learned. In this paper, we discuss the mental health and psychosocial support-focused research projects funded by R2HC; review the implications of initial findings from this research portfolio; and highlight four remaining knowledge gaps in this field. Between 2014 and 2019, R2HC funded 18 academic-practitioner partnerships focused on mental health and psychosocial support, comprising 38% of the overall portfolio (18 of 48 projects) at a value of approximately 7.2 million GBP. All projects have focused on evaluating the impact of interventions. In line with consensus-based recommendations to consider a wide range of mental health and psychosocial needs in humanitarian settings, research projects have evaluated diverse interventions. Findings so far have both challenged and confirmed widely-held assumptions about the effectiveness of mental health and psychosocial interventions in humanitarian settings. They point to the importance of building effective, sustained, and diverse partnerships between scholars, humanitarian practitioners, and funders, to ensure long-term program improvements and appropriate evidence-informed decision making. Further research needs to fill knowledge gaps regarding how to: scale-up interventions that have been found to be effective (e.g., questions related to integration across sectors, adaptation of interventions across different contexts, and optimal care systems); address neglected mental health conditions and populations (e.g., elderly, people with disabilities, sexual minorities, people with severe, pre-existing mental disorders); build on available local resources and supports (e.g., how to build on traditional, religious healing and community-wide social support practices); and ensure equity, quality, fidelity, and sustainability for interventions in real-world contexts (e.g., answering questions about how interventions from controlled studies can be transferred to more representative humanitarian contexts).All studies described here were funded by Elrha’s Research for Health in Humanitarian Crises (R2HC) Programme, which aims to improve health outcomes by strengthening the evidence base for public health interventions in humanitarian crises.14pubpu
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