Fundamental principles of absolute radiometry and the philosophy of this NBS program (1968 to 1971)

A description is given work performed on a program to develop an electrically calibrated detector (also called absolute radiometer, absolute detector, and electrically calibrated radiometer) that could be used to realize, maintain, and transfer a scale of total irradiance. The program includes a comprehensive investigation of the theoretical basis of absolute detector radiometry, as well as the design and construction of a number of detectors. A theoretical analysis of the sources of error is also included

Infrared reflectance measurements Final report, 1 Jan. 1967 - 30 Jun. 1969

Design and testing of ellipsoidal mirror reflectometer, and interferometer spectrometer measurement of mirror reflectanc

VHF command system study

Solutions are provided to specific problems arising in the GSFC VHF-PSK and VHF-FSK Command Systems in support of establishment and maintenance of Data Systems Standards. Signal structures which incorporate transmission on the uplink of a clock along with the PSK or FSK data are considered. Strategies are developed for allocating power between the clock and data, and spectral analyses are performed. Bit error probability and other probabilities pertinent to correct transmission of command messages are calculated. Biphase PCM/PM and PCM/FM are considered as candidate modulation techniques on the telemetry downlink, with application to command verification. Comparative performance of PCM/PM and PSK systems is given special attention, including implementation considerations. Gain in bit error performance due to coding is also considered

Site-vegetation relationships in the montane zone of northern Colorado

September 1965.Includes bibliographical references (pages 99-104).Author's name on piece is Jon M. Geist.Covers not scanned.Print version deaccessioned 2021.A means of determining the suitability of sites in the montane zone of northern Colorado for production of ponderosa pine and the native herbaceous vegetation from soil and landscape characteristics has not previously been developed. The objectives of this study are to identify the site factors important in determining the productivity of an area for both of these crops, and to develop a growth prediction equation, utilizing these factors, for each of the crops. Twenty sites, which spanned a continuous range of productivity, were located in portions of the Cache La Poudre River watershed in Larimer County, Colorado, Each site was investigated to determine the physical soil and landscape characteristics. Chemical soil characteristics were determined from analyses of soil samples obtained in the field. Production measurements of both crops were made at each site, also. Correlation coefficients (r) were computed between measured site factors and productivity. Some of the significantly correlated factors were used as independent variables to develop a multiple linear regression equation for each crop. The following expressions resulted, with independent variables listed in decreasing order of importance to prediction of Y: for the ponderosa pine equation Y (5-year growth index) = : +79.13 (regression constant) -.7346 X1 (percent slope) +13.63 X2 (log10 effective depth of the A horizon) -.8505 X3 (weighted mean percent clay in the A) -.0038 X4 (elevation) -.0129 X5 (weighted mean percent sand in the A) for herbaceous vegetation equation Y (mean annual herbaceous production) = : -1279 (regression constant) +17.56 X1 (cation exchange capacity index of the A horizon) +15.56 X2 (exchangeable magnesium index of the A horizon) -.9786 X3 (K2O in the A) -3.629 X4 (exch. Ca index of the A) -6.180 X5 (organic matter in the A) +.1916 X6 (elevation) +10.49 X7 (percent slope) +18.36 X8 (effective depth of the A). The multiple coefficient of determination (R2) for the ponderosa pine prediction equation was 0.66 and the R2-value for the herbaceous vegetation prediction equation was 0.84. The coefficient of variation of Y was 23.7 percent for the ponderosa pine equation and 63.3 percent for the herbaceous production equation. Correlation coefficients indicated that ponderosa pine height growth was positively correlated with the log effective depth of the A horizon, elevation, and weighted mean percent sand in the A. Negative correlations existed between height growth and the percent slope and weighted mean percent clay of the A horizon. Herbaceous production was positively correlated with all independent variables shown in the growth prediction equation except percent slope

Performance analysis of wideband data and television channels

Several aspects are discussed of space shuttle communications, including the return link (shuttle-to-ground) relayed through a satellite repeater (TDRS). The repeater exhibits nonlinear amplification and an amplitude-dependent phase shift. Models were developed for various link configurations, and computer simulation programs based on these models are described. Certain analytical results on system performance were also obtained. For the system parameters assumed, the results indicate approximately 1 db degradation relative to a link employing a linear repeater. While this degradation is dependent upon the repeater, filter bandwidths, and modulation parameters used, the programs can accommodate changes to any of these quantities. Thus the programs can be applied to determine the performance with any given set of parameters, or used as an aid in link design

Beyond the Binary: Gender Image and Experiences of Marginalization on Campus

This study explores levels of gender marginalization on college campuses in order to better understand who is at risk of being marginalized. In addition to conventional measures of sex, and gender, we explore scaled measures of how students see themselves, and how they think others see them, with respect to masculinity, femininity, and androgyny. In a survey distributed to undergraduate students, we explore experiences of gender microaggressions across the campus including experiences with pronouns, bathrooms, and interactions with staff and faculty. What we find is that marginalization based on gender is experienced by all students of all genders. Students who do not identify as transgender also experience microaggressions based on how others view their gender. Studies that aim to understand student experiences on the college campus, categorical measures of gender fall short of capturing a deeper understanding of gender identity and how those genders experience the campus

News from Academy Bay

New Faces and New Projects in a New CDRS Department. International Workshop: Feral Goat Eradication Program. Geologists to Invade Galápagos. GIS in Galápagos. The Isabela Project: Off and Running. A Pig-Free Santiago: Is it a Dream or on the Horizon? The Special Law for Galápagos

Activation of Extracellular-signal Regulated Kinase (ERK1/2) by Fluid Shear is Ca\u3csup\u3e2+\u3c/sup\u3e- and ATP-dependent in MC3T3-E1 Osteoblasts

To determine the role of Ca2+ signaling in activation of the Mitogen-Activated Protein Kinase (MAPK) pathway, we subjected MC3T3-E1 pre-osteoblastic cells to inhibitors of Ca2+ signaling during application of fluid shear stress (FSS). FSS only activated ERK1/2, rapidly inducing phosphorylation within 5 min of the onset of shear. Phosphorylation of ERK1/2 (pERK1/2) was significantly reduced when Cai2+ was chelated with BAPTA or when Ca2+ was removed from the flow media. Inhibition of both the L-type voltage-sensitive Ca2+ channel and the mechanosensitive cation-selective channel blocked FSS-induced pERK1/2. Inhibition of phospholipase C with U73122 significantly reduced pERK1/2. This inhibition did not result from blockage of intracellular Ca2+ release, but a loss of PKC activation. Recent data suggests a role of ATP release and purinergic receptor activation in mechanotransduction. Apyrase-mediated hydrolysis of extracellular ATP completely blocked FSS-induced phosphorylation of ERK1/2, while the addition of exogenous ATP to static cells mimicked the effects of FSS on pERK1/2. Two P2 receptors, P2Y2 and P2X7, have been associated with the anabolic responses of bone to mechanical loading. Using both iRNA techniques and primary osteoblasts isolated from P2X7 knockout mice, we found that the P2X7, but not the P2Y2, purinergic receptor was involved in ERK1/2 activation under FSS. These data suggest that FSS-induced ERK1/2 phosphorylation requires Ca2+-dependent ATP release, however both increased Cai2+ and PKC activation are needed for complete activation. Further, this ATP-dependent ERK1/2 phosphorylation is mediated through P2X7, but not P2Y2, purinergic receptors

¿El tamaño y la orientación del grupo intruso afecta a la distancia de iniciación al vuelo en aves?

Wildlife managers use flight initiation distance (FID), the distance animals flee an approaching predator, to determine set back distances to minimize human impacts on wildlife. FID is typically estimated by a single person; this study examined the effects of intruder number and orientation on FID. Three different group size treatments (solitary person, two people side–by–side, two people one–behind–the–other) were applied to Pied Currawongs (Strepera graculina) and to Crimson Rosellas (Platycerus elegans). Rosellas flushed at significantly greater distances when approached by two people compared to a single person. This effect was not seen in currawongs. Intruder orientation did not influence the FID of either species. Results suggest that intruder number should be better integrated into estimates of set back distance to manage human visitation around sensitive species.Los gestores de la fauna utilizan la distancia de iniciación al vuelo (FID), la distancia a la que los animales huyen cuando se les acerca un depredador, para determinar las distancias de respuesta a fin de minimizar el impacto humano en la fauna. La FID es estimada típicamente por una sola persona; este estudio examinó los efectos del número y de la orientación del intruso en la FID. Se aplicaron tres tratamientos distintos de tamaño del grupo (persona solitaria, dos personas una al lado de la otra, dos personas una detras de la otra) a currawongs cálidos (Strepera graculina) y a pericos elegantes (Platycerus elegans). Los pericos elegantes huían a distancias perceptiblemente mayores cuando se le acercaban dos personas que cuando se le acercaba una sola. Este efecto no fue observado en los currawongs pálidos. La orientación del intruso no influenció en la FID de ninguna especie. Los resultados sugieren que el número de intrusos debería ser considerado en las estimaciones de las distancias de respuesta, para poder gestionar las visitas de personas cerca de especies sensibles