Showing papers by "Virginia Tech published in 1998"
TL;DR: The NRAO VLA Sky Survey (NVSS) covers the sky north of J2000 at 1.4 GHz as discussed by the authors, including a set of 2326 4?? 4? continuum cubes with three planes containing Stokes I, Q, and U images plus a catalog of almost 2? 106 discrete sources stronger than S 2.5 mJy.
Abstract: ?????The NRAO VLA Sky Survey (NVSS) covers the sky north of J2000.0 ? = -40? (82% of the celestial sphere) at 1.4 GHz. The principal data products are (1) a set of 2326 4? ? 4? continuum cubes with three planes containing Stokes I, Q, and U images plus (2) a catalog of almost 2 ? 106 discrete sources stronger than S ? 2.5 mJy. The images all have ? = 45'' FWHM resolution and nearly uniform sensitivity. Their rms brightness fluctuations are ? ? 0.45 mJy beam-1 ? 0.14 K (Stokes I) and ? ? 0.29 mJy beam-1 ? 0.09 K (Stokes Q and U). The rms uncertainties in right ascension and declination vary from 1'' for the N ? 4 ? 105 sources stronger than 15 mJy to 7'' at the survey limit. The NVSS was made as a service to the astronomical community. All data products, user software, and updates are being released via the World Wide Web as soon as they are produced and verified.
5,441 citations
TL;DR: A detailed account of the biology of tissue cysts and bradyzoites including in vivo and in vitro development, methods of separation from host tissue, tissue cyst rupture, and relapse is provided.
Abstract: Infections by the protozoan parasite Toxoplasma gondii are widely prevalent world-wide in animals and humans. This paper reviews the life cycle; the structure of tachyzoites, bradyzoites, oocysts, sporocysts, sporozoites and enteroepithelial stages of T. gondii; and the mode of penetration of T. gondii. The review provides a detailed account of the biology of tissue cysts and bradyzoites including in vivo and in vitro development, methods of separation from host tissue, tissue cyst rupture, and relapse. The mechanism of in vivo and in vitro stage conversion from sporozoites to tachyzoites to bradyzoites and from bradyzoites to tachyzoites to bradyzoites is also discussed.
1,103 citations
TL;DR: This article found that women donate twice as much as men to their anonymous partners when any factors that might confound cooperation are eliminated, and that women are more socially-oriented than men.
Abstract: Research in social sciences other than economics indicates substan tial differences in behaviour between men and women. The general conclusion drawn from this work is that women will be more socially-orientated (selfless), and men more individually-orientated (selfish). This paper reports the results of a double-anonymous dictator experiment designed to permit the emergence of basic gender differences in economic behaviour. Our results are intended to provide a baseline for further research. We find that women, on average, donate twice as much as men to their anonymous partners when any factors that might confound cooperation are eliminated
1,029 citations
TL;DR: Findings indicate that past land-use activity, particularly agriculture, may result in long-term modifications to and reductions in aquatic diversity, regardless of reforestation of riparian zones.
Abstract: The influence of past land use on the present-day diversity of stream invertebrates and fish was investigated by comparing watersheds with different land-use history. Whole watershed land use in the 1950s was the best predictor of present-day diversity, whereas riparian land use and watershed land use in the 1990s were comparatively poor indicators. Our findings indicate that past land-use activity, particularly agriculture, may result in long-term modifications to and reductions in aquatic diversity, regardless of reforestation of riparian zones. Preservation of habitat fragments may not be sufficient to maintain natural diversity in streams, and maintenance of such biodiversity may require conservation of much or all of the watershed.
1,002 citations
TL;DR: This tutorial reviews the key concepts in spatial channel modeling and presents emerging approaches, and reviews the research issues in developing and using spatial channel models for adaptive antennas.
Abstract: Spatial antenna diversity has been important in improving the radio link between wireless users. Historically, microscopic antenna diversity has been used to reduce the fading seen by a radio receiver, whereas macroscopic diversity provides multiple listening posts to ensure that mobile communication links remain intact over a wide geographic area. In later years, the concepts of spatial diversity have been expanded to build foundations for emerging technologies, such as smart (adaptive) antennas and position location systems. Smart antennas hold great promise for increasing the capacity of wireless communications because they radiate and receive energy only in the intended directions, thereby greatly reducing interference. To properly design, analyze, and implement smart antennas and to exploit spatial processing in emerging wireless systems, accurate radio channel models that incorporate spatial characteristics are necessary. In this tutorial, we review the key concepts in spatial channel modeling and present emerging approaches. We also review the research issues in developing and using spatial channel models for adaptive antennas.
917 citations
TL;DR: In this article, a mathematical expression has been derived to give the concentration of surface hydroxyl groups as a function of the intensity ratio of the OH to O2− contributions to the O 1s photopeak.
Abstract: Quantitative XPS has been used to determine the surface concentration of hydroxyl groups in native air-formed oxide films on metals having low surface areas. A mathematical expression has been derived to give the concentration of surface hydroxyl groups as a function of the intensity ratio of the OH to O2− contributions to the O 1s photopeak. This expression is based on modeling the oxide film on a metal to be a multilayer system consisting of an outermost layer of organic contamination, a layer of chemisorbed water, a surface hydroxylated region of the oxide film and the inner portion of the oxide film. The average values of the experimentally determined concentrations of surface hydroxyl groups are 15, 13, 11, 6 and 8 OH nm−2 for oxide-covered aluminum, chromium, titanium, tantalum and silicon, respectively. X-ray photoelectron spectroscopy depth profiles using argon ion sputtering and variable-angle XPS have been utilized in this work. Surface treatments have employed either ultrasonic cleaning with organic solvents or argon plasma treatment. © 1998 John Wiley & Sons, Ltd.
800 citations
TL;DR: In this article, the authors identified forested areas that exhibit symptoms of N excess, analogous to overfertilization of arable land, and showed that some forests receiving chronic N inputs may decline in productivity and experience greate...
Abstract: Most forests in North America remain nitrogen limited, although recent studies have identified forested areas that exhibit symptoms of N excess, analogous to overfertilization of arable land. Nitrogen excess in watersheds is detrimental because of disruptions in plant/soil nutrient relations, increased soil acidification and aluminum mobility, increased emissions of nitrogenous greenhouse gases from soil, reduced methane consumption in soil, decreased water quality, toxic effects on freshwater biota, and eutrophication of coastal marine waters. Elevated nitrate (NO3−) loss to groundwater or surface waters is the primary symptom of N excess. Additional symptoms include increasing N concentrations and higher N:nutrient ratios in foliage (i.e., N:Mg, N:P), foliar accumulation of amino acids or NO3−, and low soil C:N ratios. Recent nitrogen-fertilization studies in New England and Europe provide preliminary evidence that some forests receiving chronic N inputs may decline in productivity and experience greate...
798 citations
TL;DR: In this paper, microsequencing of oligopeptides obtained by tryptic digestion of purified IscS was used to design a strategy for isolation and DNA sequence analysis of a 7,886-base pair A. vinelandii genomic segment that includes the iscS gene.
590 citations
TL;DR: This model provides a framework for understanding links between early land plant evolution and coeval marine anoxic and biotic events, but further testing of Devonian terrestrial-marine teleconnections is needed.
Abstract: The Devonian Period was characterized by major changes in both the terrestrial biosphere, e.g. the evolution of trees and seed plants and the appearance of multi-storied forests, and in the marine biosphere, e.g. an extended biotic crisis that decimated tropical marine benthos, especially the stromatoporoid-tabulate coral reef community. Teleconnections between these terrestrial and marine events are poorly understood, but a key may lie in the role of soils as a geochemical interface between the lithosphere and atmosphere/hydrosphere, and the role of land plants in mediating weathering processes at this interface. The effectiveness of terrestrial floras in weathering was significantly enhanced as a consequence of increases in the size and geographic extent of vascular land plants during the Devonian. In this regard, the most important palaeobotanical innovations were (1) arborescence (tree stature), which increased maximum depths of root penetration and rhizoturbation, and (2) the seed habit, which freed land plants from reproductive dependence on moist lowland habitats and allowed colonization of drier upland and primary successional areas. These developments resulted in a transient intensification of pedogenesis (soil formation) and to large increases in the thickness and areal extent of soils. Enhanced chemical weathering may have led to increased riverine nutrient fluxes that promoted development of eutrophic conditions in epicontinental seaways, resulting in algal blooms, widespread bottomwater anoxia, and high sedimentary organic carbon fluxes. Long-term effects included drawdown of atmospheric pCO2 and global cooling, leading to a brief Late Devonian glaciation, which set the stage for icehouse conditions during the Permo-Carboniferous. This model provides a framework for understanding links between early land plant evolution and coeval marine anoxic and biotic events, but further testing of Devonian terrestrial-marine teleconnections is needed.
571 citations
464 citations
TL;DR: A comparison of species loss at various sites before and after invasion indicates that D. polymorpha has accelerated regional extinction rates of North American freshwater mussels by 10-fold, and if this trend persists, the regional extinction rate for Mississippi basin species will be 12% per decade.
Abstract: 1. Freshwater mussels (Order Unionoida) are the most imperiled faunal group in North America; 60% of described species are considered endangered or threatened, and 12% are presumed extinct. Widespread habitat degradation (including pollution, siltation, river channelization and impoundment) has been the primary cause of extinction during this century, but a new stress was added in the last decade by the introduction of the Eurasian zebra mussel, Dreissena polymorpha, a biofouling organism that smothers the shells of other molluscs and competes with other suspension feeders for food. Since the early 1990s, it has been spreading throughout the Mississippi River basin, which contains the largest number of endemic freshwater mussels in the world. In this report, we use an exponential decay model based on data from other invaded habitats to predict the long-term impact of D. polymorpha on mussel species richness in the basin.
2. In North American lakes and rivers that support high densities (>3000 m−2) of D. polymorpha, native mussel populations are extirpated within 4–8 years following invasion. Significant local declines in native mussel populations in the Illinois and Ohio rivers, concomitant with the establishment of dense populations of D. polymorpha, suggest that induced mortality is occurring in the Mississippi River basin.
3. A comparison of species loss at various sites before and after invasion indicates that D. polymorpha has accelerated regional extinction rates of North American freshwater mussels by 10-fold. If this trend persists, the regional extinction rate for Mississippi basin species will be 12% per decade. Over 60 endemic mussels in the Mississippi River basin are threatened with global extinction by the combined impacts of the D. polymorpha invasion and environmental degradation.
01 Sep 1998
TL;DR: Two methods of creating approximation models are compared through the calculation of the modeling accuracy on test problems involving one, five, and ten independent variables to provide an initial exploration of the accuracy and modeling capabilities of these two approximation methods.
Abstract: Two methods of creating approximation models are compared through the calculation of the modeling accuracy on test problems involving one, five, and ten independent variables. Here, the test problems are representative of the modeling challenges typically encountered in realistic engineering optimization problems. The first approximation model is a quadratic polynomial created using the method of least squares. This type of polynomial model has seen considerable use in recent engineering optimization studies due to its computational simplicity and ease of use. However, quadratic polynomial models may be of limited accuracy when the response data to be modeled have multiple local extrema. The second approximation model employs an interpolation scheme known as kriging developed in the fields of spatial statistics and geostatistics. This class of interpolating model has the flexibility to model response data with multiple local extrema. However, this flexibility is obtained at an increase in computational expense and a decrease in ease of use. The intent of this study is to provide an initial exploration of the accuracy and modeling capabilities of these two approximation methods.
TL;DR: It is suggested that Mφs in different in vivo compartments may be differentially regulated by tumor‐derived molecules, which may deactivate tumor‐proximal (in situ) M φ populations while concurrently activating tumordistal M⩽s, imparting a twofold insult to the host's antitumor immune response.
Abstract: Although macrophages (Mphis) mediate tumor cytotoxicity, display tumor-associated antigens, and stimulate antitumor lymphocytes, cancer cells routinely circumvent these host-mediated immune activities, rendering the host incapable of mounting a successful antitumor immune response. Evidence supporting a direct causal relationship between cancer and immune dysfunction suggests that the presence of neoplastic tissue leads to immunologic degeneration. Furthermore, substantial data demonstrate that tumor growth adversely alters Mphi function and phenotype. Thus, although Mphis can serve as both positive and negative mediators of the immune system, the importance of Mphis in tumor-induced immune suppression remains controversial. This review focuses on the evidence that tumor-derived molecules redirect Mphi activities to promote tumor development. Tumors produce cytokines, growth factors, chemotactic molecules, and proteases that influence Mphi functions. Many tumor-derived molecules, such as IL-4, IL-6, IL-10, MDF, TGF-beta1, PGE2, and M-CSF, deactivate or suppress the cytotoxic activity of activated Mphis. Evidence that tumor-derived molecules modulate Mphi cytotoxicity and induce Mphi suppressor activity is presented. This information further suggests that Mphis in different in vivo compartments may be differentially regulated by tumor-derived molecules, which may deactivate tumor-proximal (in situ) Mphi populations while concurrently activating tumor-distal Mphis, imparting a twofold insult to the host's antitumor immune response.
TL;DR: The results reveal adipophilin as a possible new marker for the identification of specialized differentiated cells containing lipid droplets and for diseases associated with fat-accumulating cells.
Abstract: We report the human DNA and protein sequence of adipophilin and its association with the surface of lipid droplets. The amino acid sequence of human adipophilin has been determined by using cDNA clones from several tissues and confirmed by the reverse transcription/polymerase chain reaction method and Edman sequencing. The open reading frame of adipophilin encodes a polypeptide with a calculated molecular weight of 48.1 kDa and an isoelectric point of 6.72. By immunofluorescence and electron-microscopic localization with newly raised specific poly- and monoclonal antibodies, we show that this protein is not restricted to adipocytes as previously indicated by studies of the mouse homologous protein, adipose-differentiation-related protein. Adipophilin occurs in a wide range of cultured cell lines, including fibroblasts and endothelial and epithelial cells. In tissues, however, expression of adipophilin is restricted to certain cell types, such as lactating mammary epithelial cells, adrenal cortex cells, Sertoli and Leydig cells of the male reproductive system, and steatosis or fatty change hepatocytes in alcoholic liver cirrhosis. Our results reveal adipophilin as a possible new marker for the identification of specialized differentiated cells containing lipid droplets and for diseases associated with fat-accumulating cells.
TL;DR: The unique challenges and some of the proposed approaches for each of the major wireless standards for E-911 service are reviewed.
Abstract: When the FCC created the rules for wireless Enhanced 911 (E-911) service, a flurry of research and development activities dedicated to locating the position of emergency callers followed. The current deadline for this capability is October 1, 2001. We review the unique challenges and some of the proposed approaches for each of the major wireless standards.
TL;DR: Using the CLEO II detector, the authors measured the differential cross sections for exclusive two-photon production of light pseudoscalar mesons {pi}{sup 0, {eta, and {eta}{prime}.
Abstract: Using the CLEO II detector, we have measured the differential cross sections for exclusive two-photon production of light pseudoscalar mesons {pi}{sup 0}, {eta}, and {eta}{prime}. From our measurements we have obtained the form factors associated with the electromagnetic transitions {gamma}*{gamma} {yields} meson. We have measured these form factors in the momentum transfer ranges from 1.5 to 9, 20, and 30 GeV2 for {pi}{sup 0}, {eta}, and {eta}{prime}, respectively, and have made comparisons to various theoretical predictions.
TL;DR: In this article, the authors make an attempt to establish a foundation for a theory of materialism and quality of life, which posits that overall life satisfaction (quality of life) is partly determined by satisfaction with standard of living.
Abstract: An attempt is made in this paper to establish a foundation for a theory of materialism and quality of life. The theory posits that overall life satisfaction (quality of life) is partly determined by satisfaction with standard of living. Satisfaction with standard of living, in turn, is determined by evaluations of one's actual standard of living compared to a set goal. Materialists experience greater dissatisfaction with their standard of living than nonmaterialists, which in turn spills over to overall life causing dissatisfaction with life in general. Materialists experience dissatisfaction with their standard of living because they set standard of living goals that are inflated and unrealistically high. These goals set by materialists are more influenced by affective-based expectations (such as ideal, deserved, and need-based expectations) than cognitive-based ones (such as predictive, past, and ability based expectations). Materialists' ideal standard-of-living expectations are influenced by social comparisons involving remote referents, more so than comparisons involving standards that are situationally imposed. Examples of situationally-imposed standards are perceptions of wealth, income, and material possessions of family, friends, neighbors, colleagues, and so on. In contrast, examples of standards based on remote sources are perceptions of standard of living of others in one's community, town, state, country, other countries; perceptions of standard of living of others based on gender, age, education, ethnicity, occupation, and social class. This tendency to use remote referents in social comparisons may account for materialists' inflated and value-laden expectations of their standard of living. Materialists' deserved standard-of-living expectations are influenced by the tendency to engage in equity comparisons involving income and work. Thus, materialists compare themselves with others that seem to have more income and worked no harder. These equity comparisons generate feelings of inequity, injustice, anger, or envy. These emotions may also account for materialists' inflated and value-laden expectations of their standard of living. Materialists' standard-of-living expectations based on minimum needs are influenced by the tendency to spend more than generate income. This proclivity to overconsume and underproduce may be partly responsible for materialists' inflated and value-laden expectations of their standard of living.
TL;DR: A decision support technique to help decision makers study the influencing factors in the design of a hybrid solar-wind power system (HSWPS) for grid-linked applications and a novel modeling of a trade-off surface in 3-D space.
Abstract: This paper presents a decision support technique to help decision makers study the influencing factors in the design of a hybrid solar-wind power system (HSWPS) for grid-linked applications. These factors relate mainly to political and social conditions, and to technical advances and economics. The analytic hierarchy process (AHP) is used to quantify the various divergencies of opinions, practices and events that lead to confusion and uncertainties in planning HSWPS. The trade-off/risk method is used to generate multiple plans under 16 different futures and obtain the corresponding trade-off curves. Unlike the traditional 2-D simulation, a novel modeling of a trade-off surface in 3-D space is presented where the knee set is determined using the minimum distance approach. Robust and inferior plans are segregated based on their frequent occurrence in the conditional decision set of each future and hedging analysis to reduce risk is performed in order to assign alternative options in case risky futures occur.
TL;DR: The experimental distribution coefficients, K′d, for trace elements in carbonate minerals show a systematic pattern of behavior that differs from that expected if the distribution were controlled by equilibrium thermodynamics.
TL;DR: This paper contains measured data and empirical models for 5.85-GHz radio propagation path loss in and around residential areas for the newly allocated U.S. National Information Infrastructure (NII) band and develops measurement-based path loss models for propagation prediction.
Abstract: This paper contains measured data and empirical models for 5.85-GHz radio propagation path loss in and around residential areas for the newly allocated U.S. National Information Infrastructure (NII) band. Three homes and two stands of trees were studied for outdoor path loss, tree loss, and house penetration loss in a narrow-band measurement campaign that included 270 local area path loss measurements and over 276000 instantaneous power measurements. Outdoor transmitters at a height of 5.5 m were placed at distances between 30 and 210 m from the homes, to simulate typical neighborhood base stations mounted atop utility poles. All path loss data are presented graphically and coupled with site-specific information. We develop measurement-based path loss models for propagation prediction. The measurements and models may aid the development of futuristic outdoor-to-indoor residential communication systems for wireless Internet access, wireless cable distribution, and wireless local loops.
TL;DR: In this paper, improved theoretical solutions for adhesively bonded single and double-lap joints are proposed, and the improved solutions provide a better prediction for the adhesive shear distributions and maximum values, particularly in the case of fiber composite adherends.
TL;DR: Different aspects of handoff are presented and handoff related features of cellular systems are discussed and several mechanisms for evaluation of handoffs-related system performance are described.
Abstract: Handoff is an essential element of cellular communications. Efficient handoff algorithms are a cost-effective way of enhancing the capacity and QoS of cellular systems. This article presents different aspects of handoff and discusses handoff related features of cellular systems. Several system deployment scenarios that dictate specific handoff requirements are illustrated. An account of handoff-related resource management tasks of cellular systems is given. Implementation of the handoff process is explained. Several mechanisms for evaluation of handoff-related system performance are described.
TL;DR: It is concluded that imaginal desensitization, in vivo desensItization, filmed modeling, live modeling, and cognitive-behavioral interventions that use self-instruction training are probably efficacious and that participant modeling and reinforced practice are well established.
Abstract: Reviews the empirically supported status of behavioral and cognitive-behavioral interventions in the treatment of childhood phobias and anxiety disorders. For childhood phobias, it is concluded that imaginal desensitization, in vivo desensitization, filmed modeling, live modeling, and cognitive-behavioral interventions that use self-instruction training are probably efficacious and that participant modeling and reinforced practice are well established. For anxiety disorders, only cognitive-behavioral procedures with and without family anxiety management (FAM) were found to be probably efficacious. However, much of the support for these procedures comes from analogue studies conducted in research laboratory or school settings, delivered in small-group format and, not infrequently, with nonclinically referred children. Additional research that examines high-strength interventions with clinic-referred children is recommended. Furthermore, research that examines the pathological processes involved in the onset and maintenance of phobic and anxiety disorders as well as the change processes used to treat these disorders is called for.
TL;DR: In this article, the synthesis and luminescence spectroscopy of lanthanide-containing nanostructured particles, films, and composites are summarized. But the focus of this review is on the synthesis of nanoparticles.
Abstract: This review summarizes recent work in nanostructured insulating materials that contain optically active lanthanide ions. These materials find applications in lasers, optical amplifiers, and optical-display phosphors. This review concentrates on the synthesis and luminescence spectroscopy of lanthanide-containing nanostructured particles, films, and composites. Spectroscopic studies range from basic luminescence spectroscopy and quantum efficiency measurements to high-resolution spectroscopic studies that investigate the phonon dynamics and electron−phonon interaction as a function of particle size. This review identifies several areas for further study, including the location, distribution, or segregation of dopants in nanoparticles; the efficiency of energy transfer across interfaces; and the effects of quantum confinement or changes in phonon dynamics and electron−phonon interactions on the radiative and nonradiative relaxation rates in localized luminescent dopants.
TL;DR: It is shown that Golgi-resident glycosylation enzymes recycle through the ER and that this novel pathway is the likely explanation for the nocodazole-induced Golgi scattering observed in interphase cells.
Abstract: During microtubule depolymerization, the central, juxtanuclear Golgi apparatus scatters to multiple peripheral sites. We have tested here whether such scattering is due to a fragmentation process and subsequent outward tracking of Golgi units or if peripheral Golgi elements reform through a novel recycling pathway. To mark the Golgi in HeLa cells, we stably expressed the Golgi stack enzyme N-acetylgalactosaminyltransferase-2 (GalNAc-T2) fused to the green fluorescent protein (GFP) or to an 11-amino acid epitope, VSV-G (VSV), and the trans/TGN enzyme beta1,4-galactosyltransferase (GalT) fused to GFP. After nocodazole addition, time-lapse microscopy of GalNAc-T2-GFP and GalT-GFP revealed that scattered Golgi elements appeared abruptly and that no Golgi fragments tracked outward from the compact, juxtanuclear Golgi complex. Once formed, the scattered structures were relatively stable in fluorescence intensity for tens of minutes. During the entire process of dispersal, immunogold labeling for GalNAc-T2-VSV and GalT showed that these were continuously concentrated over stacked Golgi cisternae and tubulovesicular Golgi structures similar to untreated cells, suggesting that polarized Golgi stacks reform rapidly at scattered sites. In fluorescence recovery after photobleaching over a narrow (FRAP) or wide area (FRAP-W) experiments, peripheral Golgi stacks continuously exchanged resident proteins with each other through what appeared to be an ER intermediate. That Golgi enzymes cycle through the ER was confirmed by microinjecting the dominant-negative mutant of Sar1 (Sar1pdn) blocking ER export. Sar1pdn was either microinjected into untreated or nocodazole-treated cells in the presence of protein synthesis inhibitors. In both cases, this caused a gradual accumulation of GalNAc-T2-VSV in the ER. Few to no peripheral Golgi elements were seen in the nocodazole-treated cells microinjected with Sar1pdn. In conclusion, we have shown that Golgi-resident glycosylation enzymes recycle through the ER and that this novel pathway is the likely explanation for the nocodazole-induced Golgi scattering observed in interphase cells.
TL;DR: The optimal time of artificial insemination (AI) was determined from data for 2661 AI in 17 herds utilizing a radiotelemetric system for estrus detection that has the potential for continuous 24-h surveillance to monitor behavioral events associated with estrus.
TL;DR: In this article, a non-linear regression model was developed, which demonstrates that corrosion of steel in concrete in service exposure conditions is a function of the concrete chloride content, temperature and ohmic resistance, and active corrosion time.
TL;DR: In this paper, a methodology is presented to predict the displacements of flat unsymmetric epoxy-matrix composite laminates as they are cooled from their elevated cure temperature.
TL;DR: Demand heterogeneity traditionally has been defined as segments of consumers that are homogeneous with regard to the benefits they seek or in their response to marketing programs (e.g., product offloading).
Abstract: Demand heterogeneity traditionally has been defined as segments of consumers that are homogeneous with regard to the benefits they seek or in their response to marketing programs (e.g., product off...
Langley Research Center1, Virginia Tech2, State University of New York System3, Oregon State University4, Royal Meteorological Institute5, National Oceanic and Atmospheric Administration6, École Polytechnique7, Goddard Space Flight Center8, University of California, San Diego9, Colorado State University10, University of Alabama in Huntsville11
TL;DR: These algorithms are a prototype for the system that will produce the scientific data required for studying the role of clouds and radiation in the Earth's climate system, and are fundamental to the ability to understand, detect, and predict global climate change.
Abstract: The Clouds and the Earth's Radiant Energy System (CERES) is part of NASA's Earth Observing System (EOS), CERES objectives include the following. (1) For climate change analysis, provide a continuation of the Earth Radiation Budget Experiment (ERBE) record of radiative fluxes at the top-of-the-atmosphere (TOA), analyzed using the same techniques as the existing ERBE data. (2) Double the accuracy of estimates of radiative fluxes at TOA and the Earth's surface. (3) Provide the first long-term global estimates of the radiative fluxes within the Earth's atmosphere. (4) Provide cloud property estimates collocated in space and time that are consistent with the radiative fluxes from surface to TOA. In order to accomplish these goals, CERES uses data from a combination of spaceborne instruments: CERES scanners, which are an improved version of the ERBE broadband radiometers, and collocated cloud spectral imager data on the same spacecraft. The CERES cloud and radiative flux data products should prove extremely useful in advancing the understanding of cloud-radiation interactions, particularly cloud feedback effects on the Earth's radiation balance. For this reason, the CERES data should be fundamental to the ability to understand, detect, and predict global climate change. CERES results should also be very useful for studying regional climate changes associated with deforestation, desertification, anthropogenic aerosols, and ENSO events. This overview summarizes the Release 3 version of the planned CERES data products and data analysis algorithms. These algorithms are a prototype for the system that will produce the scientific data required for studying the role of clouds and radiation in the Earth's climate system.