bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Karez Concept in Ancient Chinese Sources Myth or Reality?
Authors: Trombert Éric 
Published: December 2008

AbstractThe karez (or qanât) is an ancient kind of underground waterworks that can be found still working from Iran to Morocco and, in present-day China, in Xinjiang (mostly in the Turfan Basin). In western countries and in the Middle East, historians generally consider the Iranian world as the core area of karez since the Achaemenid era (550-330 BC). In China, however, the prevailing theory concerning the origins of the karez technology in Xinjiang is that it was developed elsewhere in China's Central Plain and then imported with some minor modifications. This article intends to demonstrate that this was not the case and that the technique was unknown in the western regions at the height of the Han Chinese presence in Xinjiang in the late 8th century. This conclusion is confirmed by examining the historical process of the development of the karez technique as it is known through Qing sources. It started no sooner than the early 19th century and was related to the Qing colonial enterprise in the western regions. Le karez (ou qanât) est un type ancien d'aménagement hydraulique souterrain dont on trouve encore des exemples en activité de l'Iran au Maroc, et, en Chine aujourd'hui, au Xinjiang (principalement dans le bassin de Turfan). Dans les pays occidentaux et au Moyen Orient les historiens considèrent généralement le monde iranien comme la zone centrale des karez depuis l'époque achéménide (550-330 av. J.-C.). En Chine, en revanche, la théorie prédominante concernant l'origine de la technique des karez au Xinjiang veut que celle-ci ait été développée ailleurs dans la Plaine Centrale, pour être ensuite importée avec quelques modifications mineures. Le présent article entend démontrer que tel n'a pas été le cas et que cette technique était inconnue dans les régions occidentales à l'apogée de la présence chinoise au Xinjiang, à la fin du VIIIe siècle. Cette conclusion est confirmée par l'examen du processus historique de développement de la technique des karez telle qu'on la connaît à travers les sources d'époque Qing. Elle n'est pas apparue avant le début du XIXe siècle et doit être mise en relation avec l'entreprise coloniale des Qing dans les régions occidentales.
The Moisture Mode in the Quasi-Equilibrium Tropical Circulation Model. Part I: Analysis Based on the Weak Temperature Gradient Approximation
Authors: Sugiyama Masahiro 
Published: December 2008

Abstract
The moisture mode in a simplified version of the quasi-equilibrium tropical circulation model (QTCM) of Neelin and Zeng is analyzed. Perturbation expansion based on the ratio of temperature tendency to adiabatic cooling simplifies the system and dispersion relationship. The weak temperature gradient (WTG) approximation of Sobel, Nilsson, and Polvani naturally emerges as the dynamical balance of the moisture mode. The condition of the expansion can be phrased in terms of the nondimensional wavenumber and is satisfied in the tropics even for the planetary scale.
The WTG growth rate equation demonstrates that the moisture mode is unstable when moist static energy sources such as cloud radiative forcing and gustiness-enhanced evaporation exceed its export. Wind-induced surface heat exchange does not affect the growth rate at the leading order, although it propagates the mode eastward in the mean easterly wind. For typical values of parameters, the time scale of moisture mode instability is several days.
Nonlinear WTG calculations show that the moisture mode nonlinearly saturates by a thermodynamic limiting process. In the standard parameter regime, a phase diagram reveals two stable fixed points in addition to the unstable solution of radiative–convective equilibrium.
The Influence of Entrainment and Mixing Assumption on Aerosol–Cloud Interactions in Marine Stratocumulus
Authors: Hill Adrian A. , Feingold Graham , Jiang Hongli 
Published: December 2008

Abstract
This study uses large-eddy simulation with bin microphysics to investigate the influence of entrainment and mixing on aerosol–cloud interactions in the context of idealized, nocturnal, nondrizzling marine stratocumulus (Sc). Of particular interest are (i) an evaporation–entrainment effect and a sedimentation–entrainment effect that result from increasing aerosol concentrations and (ii) the nature of mixing between clear and cloudy air, where homogeneous and extreme inhomogeneous mixing represent the bounding mixing types. Simulations are performed at low resolution (Δz = 20 m; Δx, y = 40 m) and high resolution (Δz = 10 m; Δx, y = 20 m). It is demonstrated that an increase in aerosol from clean conditions (100 cm−3) to polluted conditions (1000 cm−3) produces both an evaporation–entrainment and a sedimentation–entrainment effect, which couple to cause about a 10% decrease in liquid water path (LWP) when all warm microphysical processes are included. These dynamical effects are insensitive to both the resolutions tested and the mixing assumption. Regardless of resolution, assuming extreme inhomogeneous rather than homogeneous mixing results in a small reduction in cloud-averaged drop number concentration, a small increase in cloud drop effective radius, and ∼1% decrease in cloud optical depth. For the case presented, these small changes play a negligible role when compared to the impact of increasing aerosol and the associated entrainment effects. Finally, it is demonstrated that although increasing resolution causes an increase in LWP and number concentration, the relative sensitivity of cloud optical depth to changes in aerosol is unaffected by resolution.
Observations and Numerical Simulations of Subrotor Vortices during T-REX
Authors: Doyle James D. , Grubišić Vanda , Brown William O. J. , De Wekker Stephan F. J. , Dörnbrack Andreas , Jiang Qingfang , Mayor Shane D. , Weissmann Martin 
Published: December 2008

Abstract
High-resolution observations from scanning Doppler and aerosol lidars, wind profiler radars, as well as surface and aircraft measurements during the Terrain-induced Rotor Experiment (T-REX) provide the first comprehensive documentation of small-scale intense vortices associated with atmospheric rotors that form in the lee of mountainous terrain. Although rotors are already recognized as potential hazards for aircraft, it is proposed that these small-scale vortices, or subrotors, are the most dangerous features because of strong wind shear and the transient nature of the vortices. A life cycle of a subrotor event is captured by scanning Doppler and aerosol lidars over a 5-min period. The lidars depict an amplifying vortex, with a characteristic length scale of ∼500–1000 m, that overturns and intensifies to a maximum spanwise vorticity greater than 0.2 s−1. Radar wind profiler observations document a series of vortices, characterized by updraft/downdraft couplets and regions of enhanced reversed flow, that are generated in a layer of strong vertical wind shear and subcritical Richardson number. The observations and numerical simulations reveal that turbulent subrotors occur most frequently along the leading edge of an elevated sheet of horizontal vorticity that is a manifestation of boundary layer shear and separation along the lee slopes. As the subrotors break from the vortex sheet, intensification occurs through vortex stretching and in some cases tilting processes related to three-dimensional turbulent mixing. The subrotors and ambient vortex sheet are shown to intensify through a modest increase in the upstream inversion strength, which illustrates the predictability challenges for the turbulent characterization of rotors.
Seasonal Variation of the Physical Properties of Marine Boundary Layer Clouds off the California Coast
Authors: Lin Wuyin , Zhang Minghua , Loeb Norman G. 
Published: December 2008

Abstract
Marine boundary layer (MBL) clouds can significantly regulate the sensitivity of climate models, yet they are currently poorly simulated. This study aims to characterize the seasonal variations of physical properties of these clouds and their associated processes by using multisatellite data. Measurements from several independent satellite datasets [International Satellite Cloud Climatology Project (ISCCP), Clouds and the Earth’s Radiant Energy System–Moderate Resolution Imaging Spectroradiometer (CERES–MODIS), Geoscience Laser Altimeter System (GLAS), and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO)], in conjunction with balloon soundings from the mobile facility of the Atmospheric Radiation Measurement (ARM) program at Point Reyes and reanalysis products, are used to characterize the seasonal variations of MBL cloud-top and cloud-base heights, cloud thickness, the degree of decoupling between clouds and MBL, and inversion strength off the California coast.
The main results from this study are as follows: (i) MBL clouds over the northeast subtropical Pacific in the summer are more prevalent and associated with a larger in-cloud water path than in winter. The cloud-top and cloud-base heights are lower in the summer than in the winter. (ii) Although the lower-tropospheric stability of the atmosphere is higher in the summer, the MBL inversion strength is only weakly stronger in the summer because of a negative feedback from the cloud-top altitude. Summertime MBL clouds are more homogeneous and are associated with lower surface latent heat flux than those in the winter. (iii) Seasonal variations of low-cloud properties from summer to winter resemble the downstream stratocumulus-to-cumulus transition of MBL clouds in terms of MBL depth, cloud-top and cloud-base heights, inversion strength, and spatial homogeneity. The “deepening–warming” mechanism of Bretherton and Wyant for the stratocumulus-to-trade-cumulus transition downstream of the cold eastern ocean can also explain the seasonal variation of low clouds from the summer to the winter, except that warming of the sea surface temperature needs to be taken as relative to the free-tropospheric air temperature, which occurs in the winter. The observed variation of low clouds from summer to winter is attributed to the much larger seasonal cooling of the free-tropospheric air temperature than that of the sea surface temperature.
Adaptive Soil Moisture Profile Filtering for Horizontal Information Propagation in the Independent Column-Based CLM2.0
Authors: De Lannoy Gabriëlle J. M. , Houser Paul R. , Verhoest Niko E. C. , Pauwels Valentijn R. N. 
Published: December 2008

Abstract
Data assimilation aims to provide an optimal estimate of the overall system state, not only for an observed state variable or location. However, large-scale land surface models are typically column-based and purely random ensemble perturbation of states will lead to block-diagonal a priori (or background) error covariance. This facilitates the filtering calculations but compromises the potential of data assimilation to influence (unobserved) vertical and horizontal neighboring state variables. Here, a combination of an ensemble Kalman filter and an adaptive covariance correction method is explored to optimize the variances and retrieve the off-block-diagonal correlations in the a priori error covariance matrix. In a first time period, all available soil moisture profile observations in a small agricultural field are assimilated into the Community Land Model, version 2.0 (CLM2.0) to find the adaptive second-order a priori error information. After that period, only observations from single individual soil profiles are assimilated with inclusion of this adaptive information. It is shown that assimilation of a single profile can partially rectify the incorrectly simulated soil moisture spatial mean and variability. The largest reduction in the root-mean-square error in the soil moisture field varies between 7% and 22%, depending on the soil depth, when assimilating a single complete profile every two days during three months with a single time-invariant covariance correction.
A Physical Method for the Calibration of the AVHRR/3 Thermal IR Channels 1: The Prelaunch Calibration Data
Authors: Mittaz Jonathan P. D. , Harris Andrew R. , Sullivan Jerry T. 
Published: December 2008

Abstract
The absolute accuracy of the thermal infrared (IR) radiances and brightness temperatures derived from the Advanced Very High Resolution Radiometer (AVHRR) is still unknown, with major sources of error not yet fully understood. This is despite the fact that data from the AVHRR IR channels are widely used in deriving important atmospheric and surface parameters as well as in weather prediction, climate modeling, and other environmental studies. Central to the problem are possible errors introduced by the calibration test procedures and methodologies that can range up to approximately 0.5 K, much larger than the instrument electronic and detector noise characteristics. Further, there are known issues with the current calibration including a large mismatch of up to 0.7 K between the measured physical temperature of the internal calibration target (ICT) and its radiometric temperature estimated by using the AVHRR-observed counts. In an effort to improve this, a new approach to the calibration has been adopted that is dependent on physical instrument parameters. It is shown that this new calibration method can explain the ICT temperature mismatch as a combination of an incorrect assumption that the AVHRR was kept at a constant temperature during testing combined with the effect of scattered radiation from the test chamber and other sources. This new calibration also reduces the total biases and errors that exist when using the current operational calibration on the prelaunch data. Comparing the external calibration target temperatures to the temperatures derived using the AVHRR measurements, this new calibration can reduce an up to 0.7-K bias seen currently to an essentially zero bias with a scatter of less than 0.05 K in the SST regime. This marks an improvement of up to an order of magnitude in accuracy over the current operational calibration.
The Skill of ECMWF Precipitation and Temperature Predictions in the Danube Basin as Forcings of Hydrological Models
Authors: Pappenberger Florian , Buizza Roberto 
Published: December 2008

Abstract
In this paper the suitability of ECMWF forecasts for hydrological applications is evaluated. This study focuses on three spatial scales: the upper Danube (which is upstream of Bratislava, Slovakia), the entire Danube catchment, and the whole of Europe. Two variables, 2-m temperature and total precipitation, are analyzed. The analysis shows that precipitation forecasts follow largely in pattern the observations. The timing of the peaks between forecasted and observed precipitation and temperature is good although precipitation amounts are often underestimated. The catchment scale influences the skill scores significantly. Small catchments exhibit a larger variance as well as larger extremes. A water balance analysis suggest a 10% underestimation by the ensemble mean and an overestimation by the high-resolution forecast over the past few years. Precipitation and temperature predictions are skillful up to days 5–7. Forecasts accumulated over a longer time frame are largely more skillful than forecasts accumulated over short time periods.
The Influence of Terrain on the Tropical Rainfall Potential Technique in Taiwan
Authors: Liu Chung-Chih 
Published: December 2008

Abstract
The tropical rainfall potential (TRaP) technique is a simple concept that serves as a useful tool for forecasters in predicting the accumulated rainfall from typhoons. This research seeks to propose an algorithm for improving the accuracy of the results retrieved from the TRaP technique by taking into account the terrain’s influence on a typhoon’s rainfall pattern over Taiwan. The climatological percentages of the accumulated rainfall in Taiwan for six different typhoon tracks were established via statistical methods. By using the rainfall percentages with the original TRaP technique, results showed that the original TRaP technique could retrieve a graphical representation of the accumulated rainfall from typhoons for both oceans and flat land areas. When factoring in Taiwan’s terrain, the accuracy in a typhoon’s accumulated rainfall estimation is seen to further improve.
Improvement of magnetic residual stress measurements based on Fourier transform
Authors: Liu H. S. , Yin C. H. , Zhang L. , Mao X. B. , Miao X. X. , Lu A. H. 
Published: December 2008

A more convenient magnetic residual stress measurement method was proposed with an improved data processing method using a Fourier transform. The effects of demagnetisation, grinding and excitation frequency were also investigated. It is found that i) the application of a Fourier transform makes the rotation of the magnetic probe redundant and leads to more convenient stress measurements ii) residual magnetisation exerts a great influence on the measurement results and thus demagnetisation is necessary for more accurate measurements iii) the stress measurement depth can be adjusted by altering the excitation frequency. The authors’ investigation provides a more convenient magnetic stress measurement method.
A functional calcium-binding site in the metalloprotease domain of ADAMTS13
Authors: Gardner Michelle D. , Chion Chan K. N. K. , de Groot Rens , Shah Anuja , Crawley James T. B. , Lane David A. 
Published: December 2008

Abstract
ADAMTS13 regulates the multimeric size of von Willebrand factor (VWF). Its function is highly dependent upon Ca2+ ions. Using the initial rates of substrate (VWF115, VWF residues 1554-1668) proteolysis by ADAMTS13 preincubated with varying Ca2+ concentrations, a high-affinity functional ADAMTS13 Ca2+-binding site was suggested with KD(app) of 80 μM (± 15 μM) corroborating a previously reported study. When Glu83 or Asp173 (residues involved in a predicted Ca2+-binding site in the ADAMTS13 metalloprotease domain) were mutated to alanine, Ca2+ dependence of proteolysis of the substrate was unaffected. Consequently, we sought and identified a candidate Ca2+-binding site in proximity to the ADAMTS13 active site, potentially comprising Glu184, Asp187, and Glu212. Mutagenesis of these residues within this site to alanine dramatically attenuated the KD(app) for Ca2+ of ADAMTS13, and for D187A and E212A also reduced the Vmax to approximately 25% of normal. Kinetic analysis of the Asp187 mutant in the presence of excess Ca2+ revealed an approximately 13-fold reduction in specificity constant, kcat/Km, contributed by changes in both Km and kcat. These results were corroborated using plasma-purified VWF as a substrate. Together, our results demonstrate that a major influence of Ca2+ upon ADAMTS13 function is mediated through binding to a high-affinity site adjacent to its active site cleft.
Chemosensitization of acute myeloid leukemia (AML) following mobilization by the CXCR4 antagonist AMD3100
Authors: Nervi Bruno , Ramirez Pablo , Rettig Michael P. , Uy Geoffrey L. , Holt Matthew S. , Ritchey Julie K. , Prior Julie L. , Piwnica-Worms David , Bridger Gary , Ley Timothy J. , DiPersio John F. 
Published: December 2008

Abstract
The CXCR4–SDF-1 axis plays a central role in the trafficking and retention of normal and malignant stem cells in the bone marrow (BM) microenvironment. Here, we used a mouse model of acute promyelocytic leukemia (APL) and a small molecule competitive antagonist of CXCR4, AMD3100, to examine the interaction of mouse APL cells with the BM microenvironment. APL cells from a murine cathepsin G-PML-RARα knockin mouse were genetically modified with firefly luciferase (APLluc) to allow tracking by bioluminescence imaging. Coculture of APLluc cells with M2-10B4 stromal cells protected the leukemia cells from chemotherapy-induced apoptosis in vitro. Upon injection into syngeneic recipients, APLluc cells rapidly migrated to the BM followed by egress to the spleen then to the peripheral blood with death due to leukostasis by day 15. Administration of AMD3100 to leukemic mice induced a 1.6-fold increase in total leukocytes and a 9-fold increase of circulating APL blast counts, which peak at 3 hours and return to baseline by 12 hours. Treatment of leukemic mice with chemotherapy plus AMD3100 resulted in decreased tumor burden and improved overall survival compared with mice treated with chemotherapy alone. These studies provide a proof-of-principle for directing therapy to the critical tethers that promote AML-niche interactions.
Regulation of growth differentiation factor 15 expression by intracellular iron
Authors: Lakhal Samira , Talbot Nick P. , Crosby Alexi , Stoepker Chantal , Townsend Alain R. M. , Robbins Peter A. , Pugh Christopher W. , Ratcliffe Peter J. , Mole David R. 
Published: December 2008

Abstract
Growth differentiation factor 15 (GDF15) is a divergent member of the transforming growth factor–β superfamily and has been identified in different contexts as a hypoxia-inducible gene product and as a molecule involved in hepcidin regulation. The biology of iron and oxygen is closely related, and known regulatory pathways involving hypoxia-inducible factor (HIF) and iron-regulatory proteins (IRPs) are responsive to both these stimuli. We therefore sought to characterize the regulation of GDF15 by iron and oxygen and to define the involvement or otherwise of HIF and IRP pathways. Here we show that GDF15 is strongly up-regulated by stimuli that deplete cells of iron and that this response is specifically antagonized by the reprovision of iron. GDF15 exhibits greater sensitivity to iron depletion than hypoxia, and responses to hypoxia and iron depletion are independent of HIF and IRP activation, suggesting a novel mechanism of regulation. We also report significant induction of serum GDF15 in iron-deficient subjects and after administration of an iron chelator to normal subjects. These findings indicate that GDF15 can be induced by pathophysiologic changes in iron availability, raising important questions about the mechanism of regulation and its role in iron homeostasis.
Viperin is required for optimal Th2 responses and T-cell receptor–mediated activation of NF-κB and AP-1
Authors: Qiu Lian-Qun , Cresswell Peter , Chin Keh-Chuang 
Published: December 2008

AbstractViperin (virus inhibitory protein, endoplasmic reticulum [ER]–associated, interferon-inducible) has been identified as a highly inducible ER protein that has antiviral activity. Here, we characterized the phenotype of mice deficient in viperin and examined the biological function of viperin in peripheral T-cell activation and differentiation. Splenic CD4+ T cells deficient in viperin exhibited normal anti–T-cell receptor (TCR)–induced proliferation and IL-2 production, but produced significantly less T helper 2 (Th2) cytokines, including IL-4, IL-5, and IL-13, in association with impaired GATA3 activation, after stimulation with anti-CD3 antibody, which was not restored upon costimulation with anti-CD28. Th2 differentiation of viperin-deficient naive T cells was also impaired in the presence of strong TCR signaling and minimum IL-4, but not under optimal Th2-skewed conditions. In parallel, viperin-deficient T cells showed decreases in NF-κB1/p50 and AP-1/JunB DNA binding activities after TCR engagement. Thus, viperin facilitates TCR-mediated GATA-3 activation and optimal Th2 cytokine production by modulating NF-κB and AP-1 activities.