2,466 research outputs found
Systematic monitoring and evaluation of M7 scanner performance and data quality
An investigation was conducted to provide the information required to maintain data quality of the Michigan M7 Multispectral scanner by systematic checks on specific system performance characteristics. Data processing techniques which use calibration data gathered routinely every mission have been developed to assess current data quality. Significant changes from past data quality are thus identified and attempts made to discover their causes. Procedures for systematic monitoring of scanner data quality are discussed. In the solar reflective region, calculations of Noise Equivalent Change in Radiance on a permission basis are compared to theoretical tape-recorder limits to provide an estimate of overall scanner performance. M7 signal/noise characteristics are examined
La coproducción del conocimiento arqueológico: la relación esencial entre aficionados y profesionales en la arqueología norteamericana durante el siglo XX
The process of professionalization in American archaeology naturally created boundaries between insiders and outsiders, with insiders having special training or degrees and institutional affiliation and employment. Amateur archaeologists, with their intimate knowledge of sites and the landscapes into which they are situated, were actively involved in trying to understand the archaeological record but were often treated as outsiders even though their insights were critical to archaeological understanding. Unfortunately, some historians of the field have taken such boundary work by professionals as given, thus writing out an important group of archaeological researchers. Using selected examples, this paper suggests the concept of “co-production of knowledge” as a useful way of thinking about the interaction of amateurs and professionals.El proceso de profesionalización de la arqueología norteamericana creó una división inevitable entre aficionados y profesionales. Por un lado, los arqueólogos profesionales recibieron una educación específica y se integraron en instituciones académicas y universidades. Por otro lado, los arqueólogos aficionados, con su conocimiento profundo de los yacimientos arqueológicos y de su contexto, fueron tratados a menudo como intrusos a pesar de que participaron activamente en la interpretación del registro arqueológico. Desgraciadamente, algunos historiadores de la arqueología han tomado dicha división por algo natural y, de este modo, han excluido a un grupo importante de arqueólogos. Utilizando ejemplos concretos, este artículo sugiere que el concepto de ‘coproducción del conocimiento’ constituye una herramienta muy útil para pensar sobre la relación entre aficionados y profesionales
Spatial land-use inventory, modeling, and projection/Denver metropolitan area, with inputs from existing maps, airphotos, and LANDSAT imagery
A landscape model was constructed with 34 land-use, physiographic, socioeconomic, and transportation maps. A simple Markov land-use trend model was constructed from observed rates of change and nonchange from photointerpreted 1963 and 1970 airphotos. Seven multivariate land-use projection models predicting 1970 spatial land-use changes achieved accuracies from 42 to 57 percent. A final modeling strategy was designed, which combines both Markov trend and multivariate spatial projection processes. Landsat-1 image preprocessing included geometric rectification/resampling, spectral-band, and band/insolation ratioing operations. A new, systematic grid-sampled point training-set approach proved to be useful when tested on the four orginal MSS bands, ten image bands and ratios, and all 48 image and map variables (less land use). Ten variable accuracy was raised over 15 percentage points from 38.4 to 53.9 percent, with the use of the 31 ancillary variables. A land-use classification map was produced with an optimal ten-channel subset of four image bands and six ancillary map variables. Point-by-point verification of 331,776 points against a 1972/1973 U.S. Geological Survey (UGSG) land-use map prepared with airphotos and the same classification scheme showed average first-, second-, and third-order accuracies of 76.3, 58.4, and 33.0 percent, respectively
Brief studies of turbojet combustor and fuel-system operation with hydrogen fuel at -400 deg f
Turbojet combustor and fuel system operation with hydrogen fuel at -400 deg
Quenching of lamellar ordering in an n-alkane embedded in nanopores
We present an X-ray diffraction study of the normale alkane nonadecane
C_{19}H_{40} embedded in nanoporous Vycor glass. The confined molecular crystal
accomplishes a close-packed structure by alignment of the rod-like molecules
parallel to the pore axis while sacrificing one basic principle known from the
bulk state, i.e. the lamellar ordering of the molecules. Despite this disorder,
the phase transitions observed in the confined solid mimic the phase behavior
of the 3D unconfined crystal, though enriched by the appearance of a true
rotator phase known only from longer alkane chains.Comment: 7 pages, 3 figure
Integrating remote sensing with nutrient management plans to calculate nitrogen parameters for swine CAFOs at the sprayfield and sub-watershed scales
No Abstract
Reusable Rocket Engine Operability Modeling and Analysis
This paper describes the methodology, model, input data, and analysis results of a reusable launch vehicle engine operability study conducted with the goal of supporting design from an operations perspective. Paralleling performance analyses in schedule and method, this requires the use of metrics in a validated operations model useful for design, sensitivity, and trade studies. Operations analysis in this view is one of several design functions. An operations concept was developed given an engine concept and the predicted operations and maintenance processes incorporated into simulation models. Historical operations data at a level of detail suitable to model objectives were collected, analyzed, and formatted for use with the models, the simulations were run, and results collected and presented. The input data used included scheduled and unscheduled timeline and resource information collected into a Space Transportation System (STS) Space Shuttle Main Engine (SSME) historical launch operations database. Results reflect upon the importance not only of reliable hardware but upon operations and corrective maintenance process improvements
Molecular Cloning and Endometrial Expression of Porcine Amphiregulin
The porcine amphiregulin gene was previously reported to be within the quantitative trait locus (QTL) for uterine capacity on chromosome 8. Because amphiregulin stimulates cell proliferation, the amphiregulin gene might be responsible for this QTL. The objectives of this study were to clone amphiregulin cDNA and compare endometrial expression of its mRNA in pregnant Meishan (M) and White composite (WC) pigs. We obtained two amphiregulin cDNAs, one with 1,221 bp and another with 1,109 bp. The 112 bp difference corresponded to exon 5 of the human amphiregulin gene, which codes for the cytoplasmic domain. Endometrial mRNA expression of amphiregulin was significantly lower in M pigs than in WC pigs during early pregnancy (day 15–40 of gestation). Amphiregulin mRNA expression in the endometrium of both M and WC pigs increased (P \u3c 0.01) from days 15 to 20, decreased (P \u3c 0.01) from days 20 to 30, and did not change between days 30 and 40. This may result in reduced amphiregulin protein production leading to the slower development of M conceptuses, contributing to greater uterine capacity and litter size in prolific Chinese M pigs. Porcine genomic sequences isolated from a bacterial artificial chromosome genomic library contained exon 5, suggesting that the deletion of exon 5 in the mRNA may be due to differential splicing. The amphiregulin gene consisted of six exons and five introns spanning 10.3 kb
Lack of Effect of Metyrapone and Exogenous Cortisol on Early Porcine Conceptus Development
In many species, including swine, fetal plasma glucocorticoids such as cortisol increase as term approaches and are responsible for final maturational changes in numerous tissues (e.g. Silver, 1990; Sangild et al. 1993, 1994; Fowden et al. 1995). On the contrary, excessive exposure to glucocorticoids during gestationmay cause intra-uterine growth retardation, developmental abnormalities or death, or lead to increased incidence of certain diseases during adult life (Blackburn et al. 1965; Reinisch et al. 1978; Seckl et al. 2000). Hence, one might speculate that a closely regulated glucocorticoid exposure is necessary throughout gestation to ensure appropriate development and survival (Klemcke et al. 1999). We have previously demonstrated in pregnant and cyclic pigs that intra-uterine cortisol increases 4- to 6.7-fold between days 10 and 19 of pregnancy (Klemcke et al. 1998). At this time (days 10–19) in conceptus (embryo plus associated extra-embryonic membranes) development, the blastocyst is undergoing quite dramatic changes (Marrable, 1971; Anderson, 1978; Anderson et al. 1993). Part of this development involves the allantois, which rapidly expands between days 18 and 30 owing to water accumulation (Bazer et al. 1981) that might in part result from Na+,K+-ATPase-generated water movement (Macknight & Leaf, 1977). Corticosteroids are known to regulate Na+,K+-ATPase in various tissues (e.g. Verrey et al. 1996)
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