361 research outputs found

    Convergent Surface Water Distributions in U.S. Cities

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    Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and distribution: in other words, cities will gain or lose water such that they become more similar to each other than are their surrounding natural landscapes. Using a database of more than 1 million water bodies and 1 million km of streams, we compared the surface water of 100 US cities with their surrounding undeveloped land. We evaluated differences in areal (A WB) and numeric densities (N WB) of water bodies (lakes, wetlands, and so on), the morphological characteristics of water bodies (size), and the density (D C) of surface flow channels (that is, streams and rivers). The variance of urban A WB, N WB, and D C across the 100 MSAs decreased, by 89, 25, and 71%, respectively, compared to undeveloped land. These data show that many cities are surface water poor relative to undeveloped land; however, in drier landscapes urbanization increases the occurrence of surface water. This convergence pattern strengthened with development intensity, such that high intensity urban development had an areal water body density 98% less than undeveloped lands. Urbanization appears to drive the convergence of hydrological features across the US, such that surface water distributions of cities are more similar to each other than to their surrounding landscapes. © 2014 The Author(s)

    Assessing the homogenization of urban land management with an application to US residential lawn care.

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    Changes in land use, land cover, and land management present some of the greatest potential global environmental challenges of the 21st century. Urbanization, one of the principal drivers of these transformations, is commonly thought to be generating land changes that are increasingly similar. An implication of this multiscale homogenization hypothesis is that the ecosystem structure and function and human behaviors associated with urbanization should be more similar in certain kinds of urbanized locations across biogeophysical gradients than across urbanization gradients in places with similar biogeophysical characteristics. This paper introduces an analytical framework for testing this hypothesis, and applies the framework to the case of residential lawn care. This set of land management behaviors are often assumed--not demonstrated--to exhibit homogeneity. Multivariate analyses are conducted on telephone survey responses from a geographically stratified random sample of homeowners (n = 9,480), equally distributed across six US metropolitan areas. Two behaviors are examined: lawn fertilizing and irrigating. Limited support for strong homogenization is found at two scales (i.e., multi- and single-city; 2 of 36 cases), but significant support is found for homogenization at only one scale (22 cases) or at neither scale (12 cases). These results suggest that US lawn care behaviors are more differentiated in practice than in theory. Thus, even if the biophysical outcomes of urbanization are homogenizing, managing the associated sustainability implications may require a multiscale, differentiated approach because the underlying social practices appear relatively varied. The analytical approach introduced here should also be productive for other facets of urban-ecological homogenization

    Profiling allele-specific gene expression in brains from individuals with autism spectrum disorder reveals preferential minor allele usage.

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    One fundamental but understudied mechanism of gene regulation in disease is allele-specific expression (ASE), the preferential expression of one allele. We leveraged RNA-sequencing data from human brain to assess ASE in autism spectrum disorder (ASD). When ASE is observed in ASD, the allele with lower population frequency (minor allele) is preferentially more highly expressed than the major allele, opposite to the canonical pattern. Importantly, genes showing ASE in ASD are enriched in those downregulated in ASD postmortem brains and in genes harboring de novo mutations in ASD. Two regions, 14q32 and 15q11, containing all known orphan C/D box small nucleolar RNAs (snoRNAs), are particularly enriched in shifts to higher minor allele expression. We demonstrate that this allele shifting enhances snoRNA-targeted splicing changes in ASD-related target genes in idiopathic ASD and 15q11-q13 duplication syndrome. Together, these results implicate allelic imbalance and dysregulation of orphan C/D box snoRNAs in ASD pathogenesis

    In Vivo MR Imaging of Magnetically Labeled Mesenchymal Stem Cells in a Rat Model of Renal Ischemia

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    Objective: This study was designed to evaluate in vivo MR imaging for the depiction of intraarterially injected superparamagnetic iron oxide (SPIO)-labeled mesenchymal stem cells (MSCs) in an experimental rat model of renal ischemia. Materials and Methods: Left renal ischemia was induced in 12 male Sprague-Dawley rats by use of the catheter lodging method. In vivo MR signal intensity variations depicted on T2*-weighted sequences were evaluated in both the left and right kidneys prior to injection (n = 2), two hours (n = 4), 15 hours (n = 2), 30 hours (n = 2) and 72 hours (n = 2) after injection of SPIO-labeled MSCs in both kidneys. Signal intensity variations were correlated with the number of Prussian blue stain-positive cells as visualized in histological specimens. Results: In an in vivo study, it was determined that there was a significant difference in signal intensity variation for both the left and right cortex (40.8 +/- 4.12 and 26.4 +/- 7.92, respectively) and for both the left and right medulla (23.2 +/- 3.32 and 15.2 +/- 3.31, respectively) until two hours after injection (p < 0.05). In addition, signal intensity variation in the left renal cortex was well correlated with the number of Prussian blue stain-positive cells per high power field (r = 0.98, p < 0.05). Conclusion: Intraarterial injected SPIO-labeled MSCs in an experimental rat model of renal ischemia can be detected with the use of in vivo MR imaging immediately after injection.This study was partly supported by a grant from the Seoul Research and Business Development Program 10548 and by a grant (A062260) from the Innovative Research Institute for Cell Therapy, Republic of Korea.Ittrich H, 2007, J MAGN RESON IMAGING, V25, P1179, DOI 10.1002/jmri.20925Hauger O, 2006, RADIOLOGY, V238, P200, DOI 10.1148/radiol.2381041668Togel F, 2005, AM J PHYSIOL-RENAL, V289, pF31, DOI 10.1152/ajprenal.00007.2005Bos C, 2004, RADIOLOGY, V233, P781, DOI 10.1148/radiol.2333031714Bulte JWM, 2004, NMR BIOMED, V17, P484, DOI 10.1002/nbm.924Grove JE, 2004, STEM CELLS, V22, P487Herzog EL, 2003, BLOOD, V102, P3483, DOI 10.1182/blood-2003-05-1664Kalish H, 2003, MAGNET RESON MED, V50, P275, DOI 10.1002/mrm.10556Frank JA, 2003, RADIOLOGY, V228, P480, DOI 10.1148/radiol.2281020638Jo SK, 2003, KIDNEY INT, V64, P43Kale S, 2003, J CLIN INVEST, V112, P42, DOI 10.1172/JCI200317856Bulte JWM, 2003, MAGNET RESON MED, V50, P201, DOI 10.1002/mrm.10511Kraitchman DL, 2003, CIRCULATION, V107, P2290, DOI 10.1161/01.CIR.0000070931.62772.4EGupta S, 2002, KIDNEY INT, V62, P1285Krause DS, 2002, GENE THER, V9, P754Bulte JWM, 2001, NAT BIOTECHNOL, V19, P1141Lewin M, 2000, NAT BIOTECHNOL, V18, P410Kelly KJ, 2000, SEMIN NEPHROL, V20, P4Firbank MJ, 1999, PHYS MED BIOL, V44, pN261, DOI 10.1088/0031-9155/44/12/403Josephson L, 1999, BIOCONJUGATE CHEM, V10, P186Sutton TA, 1998, SEMIN NEPHROL, V18, P490Thadhani R, 1996, NEW ENGL J MED, V334, P1448SHANLEY PF, 1986, AM J PATHOL, V122, P462

    Safety and Effectiveness of Central Venous Catheterization in Patients with Cancer: Prospective Observational Study

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    This study investigated the safety and effectiveness of each type of central venous catheters (CVC) in patients with cancer. We prospectively enrolled patients with cancer who underwent catherization involving a subclavian venous catheter (SVC), peripherally inserted central venous catheter (PICC), or chemo-port (CP) in our department. From March 2007 to March 2009, 116 patients underwent 179 episodes of catherization. A SVC was inserted most frequently (46.4%). Fifty-four complications occurred (30.1%): infection in 23 cases, malpositioning or migration of the tip in 18 cases, thrombosis in eight cases, and bleeding in five cases. Malpositioning or migration of the tip occurred more frequently with a PICC (P<0.001); infection occurred more often with a tunneled catheter (P=0.028) and was observed more often in young patients (P=0.023). The catheter life span was longer for patients with solid cancer (P=0.002) than for those with hematologic cancer, with a CP (P<0.001) than a PICC or SVC, and for an indwelling catheter with image guidance (P=0.014) than a blind procedure. In conclusion, CP is an effective tool for long term use and the fixation of tip is important for the management of PICC

    Fermi Large Area Telescope observations of PSR J1836+5925

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    The discovery of the gamma-ray pulsar PSR J1836+5925, powering the formerly unidentified EGRET source 3EG J1835+5918, was one of the early accomplishments of the Fermi Large Area Telescope (LAT). Sitting 25 degrees off the Galactic plane, PSR J1836+5925 is a 173 ms pulsar with a characteristic age of 1.8 million years, a spindown luminosity of 1.1×1034\times10^{34} erg s1^{-1}, and a large off-peak emission component, making it quite unusual among the known gamma-ray pulsar population. We present an analysis of one year of LAT data, including an updated timing solution, detailed spectral results and a long-term light curve showing no indication of variability. No evidence for a surrounding pulsar wind nebula is seen and the spectral characteristics of the off-peak emission indicate it is likely magnetospheric. Analysis of recent XMM observations of the X-ray counterpart yields a detailed characterization of its spectrum, which, like Geminga, is consistent with that of a neutron star showing evidence for both magnetospheric and thermal emission.Comment: Accepted to Astrophysical Journa

    Geochemical characterization of oceanic basalts using Artificial Neural Network

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    The geochemical discriminate diagrams help to distinguish the volcanics recovered from different tectonic settings but these diagrams tend to group the ocean floor basalts (OFB) under one class i.e., as mid-oceanic ridge basalts (MORB). Hence, a method is specifically needed to identify the OFB as normal (N-MORB), enriched (E-MORB) and ocean island basalts (OIB)

    The association of breast mitogens with mammographic densities

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    Radiologically dense breast tissue (mammographic density) is strongly associated with risk of breast cancer, but the biological basis for this association is unknown. In this study we have examined the association of circulating levels of hormones and growth factors with mammographic density. A total of 382 subjects, 193 premenopausal and 189 postmenopausal, without previous breast cancer or current hormone use, were selected in each of five categories of breast density from mammography units. Risk factor information, anthropometric measures, and blood samples were obtained, and oestradiol, progesterone, sex hormone binding globulin, growth hormone, insulin-like growth factor-I and its principal binding protein, and prolactin measured. Mammograms were digitised and measured using a computer-assisted method. After adjustment for other risk factors, we found in premenopausal women that serum insulin-like growth factor-I levels, and in postmenopausal women, serum levels of prolactin, were both significantly and positively associated with per cent density. Total oestradiol and progesterone levels were unrelated to per cent density in both groups. In postmenopausal women, free oestradiol (negatively), and sex hormone binding globulin (positively), were significantly related to per cent density. These data show an association between blood levels of breast mitogens and mammographic density, and suggest a biological basis for the associated risk of breast cancer
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