bluuebunny/crossref_metadata_2025_split huggingface dataset:
Autophagosome Supports Coxsackievirus B3 Replication in Host Cells
Authors: Wong Jerry , Zhang Jingchun , Si Xiaoning , Gao Guang , Mao Ivy , McManus Bruce M. , Luo Honglin 
Published: July 2008

ABSTRACT
Recent studies suggest a possible takeover of host antimicrobial autophagy machinery by positive-stranded RNA viruses to facilitate their own replication. In the present study, we investigated the role of autophagy in coxsackievirus replication. Coxsackievirus B3 (CVB3), a picornavirus associated with viral myocarditis, causes pronounced intracellular membrane reorganization after infection. We demonstrate that CVB3 infection induces an increased number of double-membrane vesicles, accompanied by an increase of the LC3-II/LC3-I ratio and an accumulation of punctate GFP-LC3-expressing cells, two hallmarks of cellular autophagosome formation. However, protein expression analysis of p62, a marker for autophagy-mediated protein degradation, showed no apparent changes after CVB3 infection. These results suggest that CVB3 infection triggers autophagosome formation without promoting protein degradation by the lysosome. We further examined the role of the autophagosome in CVB3 replication. We demonstrated that inhibition of autophagosome formation by 3-methyladenine or small interfering RNAs targeting the genes critical for autophagosome formation (ATG7, Beclin-1, and VPS34 genes) significantly reduced viral replication. Conversely, induction of autophagy by rapamycin or nutrient deprivation resulted in increased viral replication. Finally, we examined the role of autophagosome-lysosome fusion in viral replication. We showed that blockage of the fusion by gene silencing of the lysosomal protein LAMP2 significantly promoted viral replication. Taken together, our results suggest that the host's autophagy machinery is activated during CVB3 infection to enhance the efficiency of viral replication.
The Enhanced DNA Replication Fidelity of a Mutant Herpes Simplex Virus Type 1 DNA Polymerase Is Mediated by an Improved Nucleotide Selectivity and Reduced Mismatch Extension Ability
Authors: Tian Wang , Hwang Ying T. , Hwang Charles B. C. 
Published: July 2008

ABSTRACT
We previously demonstrated that a recombinant herpes simplex virus containing a mutation within the finger domain of DNA polymerase replicated DNA with increased fidelity. In this study, we demonstrate that, compared with wild-type polymerase, the mutant enzyme exhibited improved nucleotide selectivity and a reduced ability to extend from mismatched primer termini, which would contribute to the increased DNA replication fidelity.
Intrahepatic Expression of Genes Affiliated with Innate and Adaptive Immune Responses Immediately after Invasion and during Acute Infection with Woodchuck Hepadnavirus
Authors: Guy Clifford S. , Mulrooney-Cousins Patricia M. , Churchill Norma D. , Michalak Tomasz I. 
Published: July 2008

ABSTRACT
The importance of effective immune responses in recovery from acute hepadnaviral hepatitis has been demonstrated. However, there is no conclusive delineation of virological and immunological events occurring in the liver immediately after hepadnavirus invasion and during the preacute phase of infection. These very early events might be of primary importance in determining the recovery or progression to chronic hepatitis and the intrinsic hepadnaviral propensity to persist. In this study, applying the woodchuck model of acute hepatitis B, the hepatic kinetics of hepadnavirus replication and activation of genes encoding cytokines, cytotoxicity effectors, and immune cell markers were quantified in sequential liver biopsies collected from 1 h postinoculation onward by sensitive real-time cDNA amplification assays. The results revealed that hepadnavirus replication is established in the liver as early as 1 hour after infection. In 3 to 6 h, significantly augmented intrahepatic transcription of gamma interferon and interleukin-12 were evident, suggesting activation of antigen-presenting cells. In 48 to 72 h, NK and NKT cells were activated and virus replication was transiently but significantly reduced, implying that this early innate response is at least partially successful in limiting virus propagation. Nonetheless, T cells were activated 4 to 5 weeks later when hepatitis became histologically evident. Collectively, our data demonstrate that virus replication is initiated and the innate response activated in the liver soon after exposure to a liver-pathogenic dose of hepadnavirus. Nevertheless, this response is unable to prompt a timely adaptive T-cell response, in contrast to infections caused by other viral pathogens.
Data Dependence for Ishikawa Iteration When Dealing with Contractive-Like Operators
Authors: Şoltuz ŞM , Grosan Teodor 
Published: July 2008

AbstractWe prove a convergence result and a data dependence for Ishikawa iteration when applied to contraction-like operators. An example is given, in which instead of computing the fixed point of an operator, we approximate the operator with a contractive-like one. For which it is possible to compute the fixed point, and therefore to approximate the fixed point of the initial operator.
Climate, Extreme Heat, and Electricity Demand in California
Authors: Miller Norman L. , Hayhoe Katharine , Jin Jiming , Auffhammer Maximilian 
Published: July 2008

Abstract
Over the twenty-first century, the frequency of extreme-heat events for major cities in heavily air conditioned California is projected to increase rapidly. Extreme heat is defined here as the temperature threshold for the 90th-percentile excedence probability (T90) of the local warmest summer days under the current climate. Climate projections from three atmosphere–ocean general circulation models, with a range of low to midhigh temperature sensitivity forced by the Special Report on Emission Scenarios higher, middle, and lower emission scenarios, indicate that these increases in temperature extremes and variance are projected to exceed the rate of increase in mean temperature. Overall, projected increases in extreme heat under the higher A1fi emission scenario by 2070–99 tend to be 20%–30% higher than those projected under the lower B1 emission scenario. Increases range from approximately 2 times the present-day number of days for inland California cities (e.g., Sacramento and Fresno), up to 4 times for previously temperate coastal cities (e.g., Los Angeles and San Diego), implying that present-day “heat wave” conditions may dominate summer months—and patterns of electricity demand—in the future. When the projected extreme heat and observed relationships between high temperature and electricity demand for California are mapped onto current availability, maintaining technology and population constant for demand-side calculations, a potential for electricity deficits as high as 17% during T90 peak electricity demand periods is found. Similar increases in extreme-heat days are likely for other southwestern U.S. urban locations, as well as for large cities in developing nations with rapidly increasing electricity demands. In light of the electricity response to recent extreme-heat events, such as the July 2006 heat waves in California, Missouri, and New York, these results suggest that future increases in peak electricity demand will challenge current transmission and supply methods as well as future planned supply capacities when population and income growth are taken into account.
Evaluation of Cloud-Phase Retrieval Methods for SEVIRI on Meteosat-8 Using Ground-Based Lidar and Cloud Radar Data
Authors: Wolters Erwin L. A. , Roebeling Robert A. , Feijt Arnout J. 
Published: July 2008

Abstract
Three cloud-phase determination algorithms from passive satellite imagers are explored to assess their suitability for climate monitoring purposes in midlatitude coastal climate zones. The algorithms are the Moderate Resolution Imaging Spectroradiometer (MODIS)-like thermal infrared cloud-phase method, the Satellite Application Facility on Climate Monitoring (CM-SAF) method, and an International Satellite Cloud Climatology Project (ISCCP)-like method. Using one year (May 2004–April 2005) of data from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) on the first Meteosat Second Generation satellite (Meteosat-8), retrievals of the methods are compared with collocated and synchronized ground-based cloud-phase retrievals obtained from cloud radar and lidar observations at Cabauw, Netherlands. Three aspects of the satellite retrievals are evaluated: 1) instantaneous cloud-phase retrievals, 2) monthly-averaged water and ice cloud occurrence frequency, and 3) diurnal cycle of cloud phase for May–August 2004. For the instantaneous cases, all methods have a very small bias for thick water and ice cloud retrievals (∼5%). The ISCCP-like method has a larger bias for pure water clouds (∼10%), which is likely due to the 260-K threshold leading to misdetection of water clouds existing at lower temperatures. For the monthly-averaged water and ice cloud occurrence, the CM-SAF method is best capable of reproducing the annual cycle, mainly for the water cloud occurrence frequency, for which an almost constant positive bias of ∼8% was found. The ISCCP- and MODIS-like methods have more problems in detecting the annual cycle, especially during the winter months. The difference in annual cycle detection among the three methods is most probably related to the use of visible/near-infrared reflectances that enable a more direct observation of cloud phase. The diurnal cycle in cloud phase is reproduced well by all methods. The MODIS-like method reproduces the diurnal cycle best, with correlations of 0.89 and 0.86 for water and ice cloud occurrence frequency, respectively.
An Evaluation of a Diagnostic Wind Model (CALMET)
Authors: Wang Weiguo , Shaw William J. , Seiple Timothy E. , Rishel Jeremy P. , Xie Yulong 
Published: July 2008

Abstract
A U.S. Environmental Protection Agency (EPA)-approved diagnostic wind model [California Meteorological Model (CALMET)] was evaluated during a typical lake-breeze event under fair weather conditions in the Chicago region. The authors focused on the performance of CALMET in terms of simulating winds that were highly variable in space and time. The reference winds were generated by the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5) assimilating system, with which CALMET results were compared. Statistical evaluations were conducted to quantify overall model differences in wind speed and direction over the domain. Below 850 m above the surface, relative differences in (layer averaged) wind speed were about 25%–40% during the simulation period; wind direction differences generally ranged from 6° to 20°. Above 850 m, the differences became larger because of the limited number of upper-air stations near the studied domain. Analyses implied that model differences were dependent on time because of time-dependent spatial variability in winds. Trajectory analyses were made to examine the likely spatial dependence of CALMET deviations from the reference winds within the domain. These analyses suggest that the quality of CALMET winds in local areas depended on their proximity to the lake-breeze front position. Large deviations usually occurred near the front area, where observations cannot resolve the spatial variability of wind, or in the fringe of the domain, where observations are lacking. Results simulated using different datasets and model options were also compared. Differences between CALMET and the reference winds tended to be reduced with data sampled from more stations or from more uniformly distributed stations. Suggestions are offered for further improving or interpreting CALMET results under complex wind conditions in the Chicago region, which may also apply to other regions.
Asymptotic Analysis of Equilibrium in Radiation Fog
Authors: Zhou Binbin , Ferrier Brad S. 
Published: July 2008

Abstract
A vertical distribution formulation of liquid water content (LWC) for steady radiation fog was obtained and examined through the singular perturbation method. The asymptotic LWC distribution is a consequential balance among cooling, droplet gravitational settling, and turbulence in the liquid water budget of radiation fog. The cooling produces liquid water, which is depleted by turbulence near the surface. The influence of turbulence on the liquid water budget decreases with height and is more significant for shallow fogs than for deep fogs. The depth of the region of surface-induced turbulence can be characterized with a fog boundary layer (FBL). The behavior of the FBL bears some resemblance to the surface mixing layer in radiation fog. The characteristic depth of the FBL is thinner for weaker turbulence and stronger cooling, whereas if turbulence intensity increases or cooling rate decreases then the FBL will develop from the ground. The asymptotic formulation also reveals a critical turbulent exchange coefficient for radiation fog that defines the upper bound of turbulence intensity that a steady fog can withstand. The deeper a fog is, the stronger a turbulence intensity it can endure. The persistence condition for a steady fog can be parameterized by either the critical turbulent exchange coefficient or the characteristic depth of the FBL. If the turbulence intensity inside a fog is smaller than the turbulence threshold, the fog persists, whereas if the turbulence intensity exceeds the turbulence threshold or the characteristic depth of the FBL dominates the entire fog bank then the balance will be destroyed, leading to dissipation of the existing fog. The asymptotic formulation has a first-order approximation with respect to turbulence intensity. Verifications with numerical solutions and an observed fog event showed that it is more accurate for weak turbulence than for strong turbulence and that the computed LWC generally agrees with the observed LWC in magnitude.
Assessing the Errors in Shortwave Radiative Fluxes Inferred from the Geostationary Earth Radiation Budget (GERB) Instrument in the Presence of Dust Aerosol
Authors: Brindley Helen E. , Russell Jacqueline E. 
Published: July 2008

Abstract
The Geostationary Earth Radiation Budget (GERB) instruments flying on the Meteosat Second Generation series of satellites provide a unique tool with which to monitor the diurnal evolution of top-of-atmosphere broadband radiation fields. GERB products, which have recently been released to the scientific community, include aerosol information in addition to the observed radiances and inferred fluxes. However, no account of the anisotropic characteristics of aerosol has been incorporated in the radiance-to-flux conversion, which uses angular distribution models developed for clear or cloudy conditions. Here an attempt is made to quantify the impact of this omission in the shortwave (SW), focusing on dust-contaminated scenes. An observationally based representation of dust is used to develop a theoretical angular distribution model, which is tested through comparison with observed GERB radiances. For dusty scenes that have been processed as clear ocean, applying the dust model to convert GERB radiances to fluxes reduces the SW reflected flux by an average of approximately 12 W m−2 relative to the original GERB fluxes. This value ranges from −4 to +55 W m−2, depending on observation geometry and dust loading. For dusty scenes that the GERB processing has treated as cloudy, GERB fluxes are generally smaller than values obtained using the dust-specific model. On average, over the time period studied here, the two effects partially cancel, and the overall mean difference is 2.5 W m−2. However, it is shown that this cancellation is highly sensitive to the location and time period under consideration.
Precipitating Snow Retrievals from Combined Airborne Cloud Radar and Millimeter-Wave Radiometer Observations
Authors: Grecu Mircea , Olson William S. 
Published: July 2008

Abstract
An algorithm for retrieving snow over oceans from combined cloud radar and millimeter-wave radiometer observations is developed. The algorithm involves the use of physical models to simulate cloud radar and millimeter-wave radiometer observations from basic atmospheric variables such as hydrometeor content, temperature, and relative humidity profiles and is based on an optimal estimation technique to retrieve these variables from actual observations. A high-resolution simulation of a lake-effect snowstorm by a cloud-resolving model is used to test the algorithm. That is, synthetic observations are generated from the output of the cloud numerical model, and the retrieval algorithm is applied to the synthetic data. The algorithm performance is assessed by comparing the retrievals with the reference variables used in synthesizing the observations. The synthetic observation experiment indicates good performance of the retrieval algorithm. The algorithm is also applied to real observations from the Wakasa Bay field experiment that took place over the Sea of Japan in January and February 2003. The application of the retrieval algorithm to data from the field experiment yields snow estimates that are consistent with both the cloud radar and radiometer observations.
On the Relationship between North Atlantic Sea Surface Temperatures and U.S. Hurricane Landfall Risk
Authors: Dailey Peter S. , Zuba Gerhard , Ljung Greta , Dima Ioana M. , Guin Jayanta 
Published: July 2008

AbstractIn the recent literature, considerable attention has been paid to the relationship between climate signals and tropical cyclone activity. Much of the research has focused on Atlantic Ocean basin activity while less attention has been given to landfall frequency and the geographic distribution of risk to life and property. However, recent active seasons like 2004 and 2005 and the resulting damage and economic loss have generated significant interest in the relationship between climate and landfall risk. This study focuses on sea surface temperatures (SST) and examines modulation of landfall activity occurring in anomalously warm-SST seasons. The objective of the study is to evaluate the effect of warmer ocean conditions on U.S. landfall risk. The study is broken into two parts–—statistical and physical. The statistical analysis categorizes historical hurricane seasons as either warm or cool and then estimates shifts in landfall frequency under these two climate modes. The analysis is carried out for overall U.S. landfall risk and then for logical subregions along the U.S. coastline. The climatological behavior for warm-SST conditions is developed across the intensity spectrum, from weak tropical storms to major hurricanes, using wind speed as an intensity measure. The analysis suggests that landfall risk is sensitive to SST conditions but that sensitivity varies by region and intensity. The uncertainty associated with these estimates is discussed. The physical analysis is carried out to understand better why landfall risk is not affected uniformly along the U.S. coastline and to reinforce the reasonability of the statistical results. The study involves a detailed examination of the complete life cycle of historical storms. Results indicate that storms making landfall along the East Coast have different genesis and intensification characteristics relative to storms making landfall along the Gulf Coast. As SSTs warm, the genesis pattern shifts, greatly influencing regional landfall risk. Further, hurricane landfalls may react not only to warm-SST conditions, but also to the effect of ocean temperature anomalies on the atmosphere’s general circulation. There are implications that complex feedback mechanisms play a role in modulating the probability of landfall, especially from certain parts of the Atlantic basin. Such physical theories provide added confidence in statistical estimates of elevated risk for certain breeds of tropical cyclones.
A Toy Model of the Instability in the Equatorially Trapped Convectively Coupled Waves on the Equatorial Beta Plane
Authors: Andersen Joseph Allan , Kuang Zhiming 
Published: July 2008

Abstract
The equatorial atmospheric variability shows a spectrum of significant peaks in the wavenumber–frequency domain. These peaks have been identified with the equatorially trapped wave modes of rotating shallow water wave theory. This paper addresses the observation that the various wave types (e.g., Kelvin, Rossby, etc.) and wavenumbers show differing signal strength relative to a red background. It is hypothesized that this may be due to variations in the linear stability of the atmosphere in response to the various wave types depending on both the specific wave type and the wavenumber. A simple model of the convectively coupled waves on the equatorial beta plane is constructed to identify processes that contribute to this dependence. The linear instability spectrum of the resulting coupled system is evaluated by eigenvalue analysis. This analysis shows unstable waves with phase speeds, growth rates, and structures (vertical and horizontal) that are broadly consistent with the results from observations. The linear system, with an idealized single intertropical convergence zone (ITCZ) as a mean state, shows peak unstable Kelvin waves around zonal wavenumber 7 with peak growth rates of ∼0.08 day−1 (e-folding time of ∼13 days). The system also shows unstable mixed Rossby–gravity (MRG) and inertio-gravity waves with significant growth in the zonal wavenumber range from −15 (negative indicates westward phase speed) to +10 (positive indicates eastward phase speed). The peak MRG n = 0 eastward inertio-gravity wave (EIG) growth rate is around one-third that of the Kelvin wave and occurs at zonal wavenumber 3. The Rossby waves in this system are stable, and the Madden–Julian oscillation is not observed. Within this model, it is shown that in addition to the effect of the ITCZ configuration, the differing instabilities of the different wave modes are also related to their different efficiency in converting input energy into divergent flow. This energy conversion efficiency difference is suggested as an additional factor that helps to shape the observed wave spectrum.
Key Dynamical Features of the 2005/06 European Winter
Authors: Croci-Maspoli Mischa , Davies Huw C. 
Published: July 2008

Abstract
A three-part study of the anomalously cold European winter of 2005/06 is undertaken. Climatological analysis indicates that the dominant pattern of climate variability in the Euro–Atlantic sector during this winter was not a negative phase of the North Atlantic Oscillation (NAO), but a pattern with a “blocklike” center located immediately upstream of the continent. Synoptic-dynamical diagnosis of the winter indicates the frequent occurrence of long-lasting blocks in this region, and a Lagrangian trajectory analysis points to the significant role of cloud-diabatic effects in the dynamics of block inception. A series of heuristic numerical simulations lend credence to the hypothesis that the occurrence of the blocks was sensitive to, and significantly influenced by, the warm surface temperature anomalies upstream over the western Atlantic Ocean and North America. Brief comments are made on the significance of the foregoing results for seasonal numerical weather prediction and also their relevance to the consideration of interannual climate variability.