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Fang S.-X.,Chinese Academy of Meteorological Sciences | Zhou L.-X.,Chinese Academy of Meteorological Sciences | Masarie K.A.,Boulder CO | Xu L.,Chinese Academy of Meteorological Sciences | Rella C.W.,Picarro Inc.
Journal of Geophysical Research: Atmospheres | Year: 2013

Atmospheric CH4 mole fractions were continuously measured from 2009 to 2011 at three WMO/GAW stations in China (Lin'an, LAN; Longfengshan, LFS; and Waliguan, WLG) using three Cavity Ring Down Spectroscopy instruments. LAN and LFS are GAW regional measurement stations. LAN is located in China's most economically developed region, and LFS is in a rice production area (planting area > 40,000 km2). WLG is a global measurement station in remote northwest China. At LAN, high methane mole fractions are observed in all seasons. Surface winds from the northeast enhance CH4 values, with a maximum increase of 32 ± 15 ppb in summer. The peak to peak amplitude of the seasonal cycle is 77 ± 35 ppb. At LFS, the diurnal cycle amplitude is approximately constant throughout the year except summer, when a value of 196 ± 65 ppb is observed. CH4 values at LFS reach their peak in July, which is different from seasonal variations typically observed in the northern hemisphere. CH4 mole fractions at WLG show both the smallest values and the lowest variability. Maximum values occur during summer, which is different from other northern hemisphere WMO/GAW global stations. The seasonal cycle amplitude is 17 ± 11 ppb. The linear growth rates at LAN, LFS, and WLG are 8.0 ± 1.2, 7.9 ± 0.9, and 9.4 ± 0.2 ppb yr -1, respectively, which are all larger than the global mean over the same 3 year period. Results from this study attempt to improve our basic understanding of observed atmospheric CH4 in China. Key Points measurement of atmospheric CH4 at the WMO/GAW stations in Chinathe variations of atmospheric CH4 are studiedthe factors infectng CH4 mole fractions are analysed ©2013. American Geophysical Union. All Rights Reserved. Source


A meta-analysis of spine BMD dose-response relationships for alendronate, risedronate, and ibandronate was performed. Data from all three oral bisphosphonates conform to a log-linear relationship between dose and change in spine BMD relative to placebo at 1 year, with an incremental gain of about 1 % for each doubling of dose. Introduction: Animal data suggesting differences in potency and differences in approved oral dosage strengths for alendronate, risedronate, and ibandronate in the treatment of osteoporosis raise questions about their dose-response relationships and relative potencies in humans. Methods: A meta-analysis of dose-response relationships for spine BMD increases for these three bisphosphonates was performed using data from 21 placebo-controlled trials that collectively included over 13,000 patients on active treatment and over 8,000 on placebo. Results: For alendronate over the range of 1 to 20 mg/day, there was a strong log-linear relationship between dose and the increase in spine BMD relative to placebo at 1 year (R 2 = 0.994 using sample-weighted means). For each doubling in alendronate dose, there was an incremental gain of about 1 % in spine BMD. On the same scale, risedronate and ibandronate are approximately equipotent to alendronate on a weight-for-weight basis. The increases in BMD efficacy with each doubling of dose are parallel for all three nitrogen-containing bisphosphonates (NCBPs). Conclusions: All three NCBPs are approximately equipotent and exhibit a log-linear relationship between dose and the increase in spine BMD. Differences in efficacy between the available oral bisphosphonate regimens appear to be a function of dose rather than inherent differences in therapeutic potential. © 2012 International Osteoporosis Foundation and National Osteoporosis Foundation. Source


Rabern L.,Boulder CO
Electronic Journal of Combinatorics | Year: 2011

We prove that if G is the line graph of a multigraph, then the chromatic number χ(G) of G is at most max {ω(G), 7Δ(G)+10/8} where ω(G) and Δ(G) are the clique number and the maximum degree of G, respectively. Thus Brooks' Theorem holds for line graphs of multigraphs in much stronger form. Using similar methods we then prove that if G is the line graph of a multigraph with χ(G) ≥ Δ(G) ≥ 9, then G contains a clique on Δ(G) vertices. Thus the Borodin-Kostochka Conjecture holds for line graphs of multigraphs. Source


Kieffer H.H.,Celestial Reasonings | Kieffer H.H.,Boulder CO
Journal of Geophysical Research E: Planets | Year: 2013

The KRC numerical thermal model has been used in the analysis of observations from virtually all Mars missions with infrared sensors and for the selection of virtually all Mars' landing sites. It uses a physics-based one-layer atmosphere gray at solar and thermal wavelengths to determine the radiative effect of a dusty atmosphere. One gas component may condense to form a seasonal polar cap and affect the global surface pressure. The atmosphere may be omitted entirely to model airless bodies. KRC uses layers that become thicker geometrically with depth and it uses repeated time step doubling. The surface may be homogeneous or have two zones of material properties, each zone may have temperature-dependent thermal conductivity and specific heat. Surface slopes or depressions are modeled to first order. Here KRC is described in detail and used to compute globally the annual average surface temperature accounting for albedo, thermal inertia, elevation, slope at 3 km resolution, and zonal climate. Comparisons with three other thermal models are discussed. The model is available for general use. Key Points Allows derivation of surface physical properties from infrared observations KRC is versatile and fast KRC has been widely used in publications ©2012. American Geophysical Union. All Rights Reserved. Source


Pifko S.,Stanford University | Janches D.,NASA | Close S.,Stanford University | Sparks J.,University of Washington | And 2 more authors.
Icarus | Year: 2013

The majority of extraterrestrial particles entering Earth's atmosphere originate from the Sporadic Meteoroid Complex (SMC) and are associated with many mesospheric layer phenomena. The Meteoroid Input Function (MIF) is a model that has been developed with the purpose of understanding the temporal and spatial variability of the meteoroid impact in the atmosphere. The MIF has been shown to accurately predict the seasonal and diurnal variations of the meteor flux observed by High Power Large Aperture (HPLA) radars at various geographic locations, including the Arecibo Observatory (AO) and the Poker Flat Incoherent Scatter Radar (PFISR). For this, the model requires the assessment of a potential observational bias of the particular HPLA radar utilized: the minimum detectable radar cross-section (RCS). The RCS sensitivity threshold provides a metric to characterize the radar system's ability to detect particles with a given mass and speed. In this paper, the MIF model was used to predict meteor properties (e.g. the distributions of areal density, speed, and radiant location) observed by the Middle and Upper atmosphere (MU) radar while leveraging the system's interferometric capability to address the model's ability to predict meteor observations at middle geographic latitudes and for a radar operating frequency in the low VHF band. This study demonstrates that the MIF accurately considered the speed and sporadic source distributions for the portion of the meteoroid population observable by the MU radar, and the applicability of the MIF to the MU system increases the confidence of using it as a global model. © 2013 Elsevier Inc. Source

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