Allan Urho Paivio (1925-2016).

PubMed

Katz, Albert

2017-01-01

Presents an obituary for Allan Urho Paivio, who passed away on June 19, 2016. One of his many accomplishments was the development of a dual-coding theory. Dual-coding theory, while very influential, has, unfortunately, been discussed all too often as a theory of mental imagery, and not within its larger context wherein mental imagery and verbal processes are separable but interconnected representational systems, an academic battle in clarification that Paivio waged much of his life. He published prodigiously, even in the decades after retirement. Among his many honors, he served as president of the Canadian Psychological Association (1975) and was appointed a fellow of the Royal Society of Canada (1978). (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Quantifying the Precision of Single-Molecule Torque and Twist Measurements Using Allan Variance.

PubMed

van Oene, Maarten M; Ha, Seungkyu; Jager, Tessa; Lee, Mina; Pedaci, Francesco; Lipfert, Jan; Dekker, Nynke H

2018-04-24

Single-molecule manipulation techniques have provided unprecedented insights into the structure, function, interactions, and mechanical properties of biological macromolecules. Recently, the single-molecule toolbox has been expanded by techniques that enable measurements of rotation and torque, such as the optical torque wrench (OTW) and several different implementations of magnetic (torque) tweezers. Although systematic analyses of the position and force precision of single-molecule techniques have attracted considerable attention, their angle and torque precision have been treated in much less detail. Here, we propose Allan deviation as a tool to systematically quantitate angle and torque precision in single-molecule measurements. We apply the Allan variance method to experimental data from our implementations of (electro)magnetic torque tweezers and an OTW and find that both approaches can achieve a torque precision better than 1 pN · nm. The OTW, capable of measuring torque on (sub)millisecond timescales, provides the best torque precision for measurement times ≲10 s, after which drift becomes a limiting factor. For longer measurement times, magnetic torque tweezers with their superior stability provide the best torque precision. Use of the Allan deviation enables critical assessments of the torque precision as a function of measurement time across different measurement modalities and provides a tool to optimize measurement protocols for a given instrument and application. Copyright © 2018 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Horror from the Soul--Gothic Style in Allan Poe's Horror Fictions

ERIC Educational Resources Information Center

Sun, Chunyan

2015-01-01

Edgar Allan Poe made tremendous contribution to horror fiction. Poe's inheritance of gothic fiction and American literature tradition combined with his living experience forms the background of his horror fictions. He inherited the tradition of the gothic fictions and made innovations on it, so as to penetrate to subconsciousness. Poe's horror…

Allan M. Freedman, LLB: a lawyer’s gift to Canadian chiropractors

PubMed Central

Brown, Douglas M.

2007-01-01

This paper reviews the leadership role, contributions, accolades, and impact of Professor Allan Freedman through a 30 year history of service to CMCC and the chiropractic profession in Canada. Professor Freedman has served as an educator, philanthropist and also as legal counsel. His influence on chiropractic organizations and chiropractors during this significant period in the profession is discussed. PMID:18060008

Quantifying noise in optical tweezers by allan variance.

PubMed

Czerwinski, Fabian; Richardson, Andrew C; Oddershede, Lene B

2009-07-20

Much effort is put into minimizing noise in optical tweezers experiments because noise and drift can mask fundamental behaviours of, e.g., single molecule assays. Various initiatives have been taken to reduce or eliminate noise but it has been difficult to quantify their effect. We propose to use Allan variance as a simple and efficient method to quantify noise in optical tweezers setups.We apply the method to determine the optimal measurement time, frequency, and detection scheme, and quantify the effect of acoustic noise in the lab. The method can also be used on-the-fly for determining optimal parameters of running experiments.

Looking at the "Next" 20 Years of Multiliteracies: A Discussion with Allan Luke

ERIC Educational Resources Information Center

Garcia, Antero; Luke, Allan; Seglem, Robyn

2018-01-01

In this discussion with literacies researcher Allan Luke, the New London Group Member reflects on the role of multiliteracies in shaping literacies research and the continuing changes to technology, capitalism, and learning. Focused on looking toward future advances in literacies research, Luke reflects on the role of multiliteracies in…

Uranium series dating of Allan Hills ice

NASA Technical Reports Server (NTRS)

Fireman, E. L.

1986-01-01

Uranium-238 decay series nuclides dissolved in Antarctic ice samples were measured in areas of both high and low concentrations of volcanic glass shards. Ice from the Allan Hills site (high shard content) had high Ra-226, Th-230 and U-234 activities but similarly low U-238 activities in comparison with Antarctic ice samples without shards. The Ra-226, Th-230 and U-234 excesses were found to be proportional to the shard content, while the U-238 decay series results were consistent with the assumption that alpha decay products recoiled into the ice from the shards. Through this method of uranium series dating, it was learned that the Allen Hills Cul de Sac ice is approximately 325,000 years old.

Where Were the Whistleblowers? The Case of Allan McDonald and Roger Boisjoly.

ERIC Educational Resources Information Center

Stewart, Lea P.

Employees who "blow the whistle" on their company because they believe it is engaged in practices that are illegal, immoral, or harmful to the public, often face grave consequences for their actions, including demotion, harassment, forced resignation, or termination. The case of Allan McDonald and Roger Boisjoly, engineers who blew the…

Observation, Inference, and Imagination: Elements of Edgar Allan Poe's Philosophy of Science

ERIC Educational Resources Information Center

Gelfert, Axel

2014-01-01

Edgar Allan Poe's standing as a literary figure, who drew on (and sometimes dabbled in) the scientific debates of his time, makes him an intriguing character for any exploration of the historical interrelationship between science, literature and philosophy. His sprawling "prose-poem" "Eureka" (1848), in particular, has…

European Studies as Answer to Allan Bloom's "The Closing of the American Mind."

ERIC Educational Resources Information Center

Macdonald, Michael H.

European studies can provide a solution to several of the issues raised in Allan Bloom's "The Closing of the American Mind." European studies pursue the academic quest for what is truth, what is goodness, and what is beauty. In seeking to answer these questions, the Greeks were among the first to explore many of humanity's problems and…

Playing on the Right Side of the Brain: An Interview with Allan N. Schore

ERIC Educational Resources Information Center

American Journal of Play, 2017

2017-01-01

Allan N. Schore has served on the clinical faculty of the Department of Psychiatry and Biobehavioral Sciences at UCLA's David Geffen School of Medicine since 1996 and has maintained a private clinical practice for more than four decades. He has contributed significant research to the disciplines of interpersonal neurobiology, affective…

[Exome sequencing revealed Allan-Herndon-Dudley syndrome underlying multiple disabilities].

PubMed

Arvio, Maria; Philips, Anju K; Ahvenainen, Minna; Somer, Mirja; Kalscheuer, Vera; Järvelä, Irma

2014-01-01

Normal function of the thyroid gland is the cornerstone of a child's mental development and physical growth. We describe a Finnish family, in which the diagnosis of three brothers became clear after investigations that lasted for more than 30 years. Two of the sons have already died. DNA analysis of the third one, a 16-year-old boy, revealed in exome sequencing of the complete X chromosome a mutation in the SLC16A2 gene, i.e. MCT8, coding for a thyroid hormone transport protein. Allan-Herndon-Dudley syndrome was thus shown to be the cause of multiple disabilities.

Obituary: Allan R. Sandage (1926-2010)

NASA Astrophysics Data System (ADS)

Devorkin, David

2011-12-01

Allan Rex Sandage died of pancreatic cancer at his home in San Gabriel, California, in the shadow of Mount Wilson, on November 13, 2010. Born in Iowa City, Iowa, on June 18, 1926, he was 84 years old at his death, leaving his wife, former astronomer Mary Connelly Sandage, and two sons, David and John. He also left a legacy to the world of astronomical knowledge that has long been universally admired and appreciated, making his name synonymous with late 20th-Century observational cosmology. The only child of Charles Harold Sandage, a professor of advertising who helped establish that academic specialty after obtaining a PhD in business administration, and Dorothy Briggs Sandage, whose father was president of Graceland College in Iowa, Allan Sandage grew up in a thoroughly intellectual, university oriented atmosphere but also a peripatetic one taking him to Philadelphia and later to Illinois as his father rose in his career. During his 2 years in Philadelphia, at about age eleven, Allan developed a curiosity about astronomy stimulated by a friend's interest. His father bought him a telescope and he used it to systematically record sunspots, and later attempted to make a larger 6-inch reflector, a project left uncompleted. As a teenager Allan read widely, especially astronomy books of all kinds, recalling in particular The Glass Giant of Palomar as well as popular works by Eddington and Hubble (The Realm of the Nebulae) in the early 1940s. Although his family was Mormon, of the Reorganized Church, he was not practicing, though he later sporadically attended a Methodist church in Oxford, Iowa during his college years. Sandage knew by his high school years that he would engage in some form of intellectual life related to astronomy. He particularly recalls an influential science teacher at Miami University in Oxford, Ohio named Ray Edwards, who inspired him to think critically and "not settle for any hand-waving of any kind." [Interview of Allan Rex Sandage by Spencer

An Interview with Allan Wigfield: A Giant on Research on Expectancy Value, Motivation, and Reading Achievement

ERIC Educational Resources Information Center

Bembenutty, Hefer

2012-01-01

This article presents an interview with Allan Wigfield, professor and chair of the Department of Human Development and distinguished scholar-teacher at the University of Maryland. He has authored more than 100 peer-reviewed journal articles and book chapters on children's motivation and other topics. He is a fellow of Division 15 (Educational…

Discrimination of isotrigon textures using the Rényi entropy of Allan variances.

PubMed

Gabarda, Salvador; Cristóbal, Gabriel

2008-09-01

We present a computational algorithm for isotrigon texture discrimination. The aim of this method consists in discriminating isotrigon textures against a binary random background. The extension of the method to the problem of multitexture discrimination is considered as well. The method relies on the fact that the information content of time or space-frequency representations of signals, including images, can be readily analyzed by means of generalized entropy measures. In such a scenario, the Rényi entropy appears as an effective tool, given that Rényi measures can be used to provide information about a local neighborhood within an image. Localization is essential for comparing images on a pixel-by-pixel basis. Discrimination is performed through a local Rényi entropy measurement applied on a spatially oriented 1-D pseudo-Wigner distribution (PWD) of the test image. The PWD is normalized so that it may be interpreted as a probability distribution. Prior to the calculation of the texture's PWD, a preprocessing filtering step replaces the original texture with its localized spatially oriented Allan variances. The anisotropic structure of the textures, as revealed by the Allan variances, turns out to be crucial later to attain a high discrimination by the extraction of Rényi entropy measures. The method has been empirically evaluated with a family of isotrigon textures embedded in a binary random background. The extension to the case of multiple isotrigon mosaics has also been considered. Discrimination results are compared with other existing methods.

The History of Allan Hills 84001 Revised: Multiple Shock Events

NASA Technical Reports Server (NTRS)

Treiman, Allan H.

1998-01-01

The geologic history of Martian meteorite Allan Hills (ALH) 84001 is more complex than previously recognized, with evidence for four or five crater-forming impacts onto Mars. This history of repeated deformation and shock metamorphism appears to weaken some arguments that have been offered for and against the hypothesis of ancient Martian life in ALH 84001. Allan Hills 84001 formed originally from basaltic magma. Its first impact event (I1) is inferred from the deformation (D1) that produced the granular-textured bands ("crush zones") that transect the original igneous fabric. Deformation D1 is characterized by intense shear and may represent excavation or rebound flow of rock beneath a large impact crater. An intense thermal metamorphism followed D1 and may be related to it. The next impact (I2) produced fractures, (Fr2) in which carbonate "pancakes" were deposited and produced feldspathic glass from some of the igneous feldspars and silica. After I2, carbonate pancakes and globules were deposited in Fr2 fractures and replaced feldspathic glass and possibly crystalline silicates. Next, feldspars, feldspathic glass, and possibly some carbonates were mobilized and melted in the third impact (I3). Microfaulting, intense fracturing, and shear are also associated with 13. In the fourth impact (I4), the rock was fractured and deformed without significant heating, which permitted remnant magnetization directions to vary across fracture surfaces. Finally, ALH 84001 was ejected from Mars in event I5, which could be identical to I4. This history of multiple impacts is consistent with the photogeology of the Martian highlands and may help resolve some apparent contradictions among recent results on ALH 84001. For example, the submicron rounded magnetite grains in the carbonate globules could be contemporaneous with carbonate deposition, whereas the elongate magnetite grains, epitaxial on carbonates, could be ascribed to vapor-phase deposition during I3.

Evaluating the Duration and Continuity of Potential Climate Records From the Allan Hills Blue Ice Area, East Antarctica

NASA Astrophysics Data System (ADS)

Kehrl, Laura; Conway, Howard; Holschuh, Nicholas; Campbell, Seth; Kurbatov, Andrei V.; Spaulding, Nicole E.

2018-05-01

The current ice core record extends back 800,000 years. Geologic and glaciological evidence suggests that the Allan Hills Blue Ice Area, East Antarctica, may preserve a continuous record that extends further back in time. In this study, we use ice-penetrating radar and existing age constraints to map the internal stratigraphy and age structure of the Allan Hills Main Ice Field. The dated isochrones provide constraints for an ice flow model to estimate the age of ice near the bed. Previous drilling in the region recovered stratigraphically disturbed sections of ice up to 2.7 million years old. Our study identifies a site 5 km upstream, which likely preserves a continuous record through Marine Isotope Stage 11 with the possibility that the record extends back 1 million years. Such records would provide new insight into the past climate and glacial history of the Ross Sea Sector.

Allan deviation analysis of financial return series

NASA Astrophysics Data System (ADS)

Hernández-Pérez, R.

2012-05-01

We perform a scaling analysis for the return series of different financial assets applying the Allan deviation (ADEV), which is used in the time and frequency metrology to characterize quantitatively the stability of frequency standards since it has demonstrated to be a robust quantity to analyze fluctuations of non-stationary time series for different observation intervals. The data used are opening price daily series for assets from different markets during a time span of around ten years. We found that the ADEV results for the return series at short scales resemble those expected for an uncorrelated series, consistent with the efficient market hypothesis. On the other hand, the ADEV results for absolute return series for short scales (first one or two decades) decrease following approximately a scaling relation up to a point that is different for almost each asset, after which the ADEV deviates from scaling, which suggests that the presence of clustering, long-range dependence and non-stationarity signatures in the series drive the results for large observation intervals.

Allan Franklin, Shifting Standards: Experiments in Particle Physics in the Twentieth Century. Book Review

DOE PAGES

Pronskikh, Vitaly

2015-10-01

The book Shifting Standards is a valuable contribution to the literature on the history and philosophy of science and specifically to the philosophy of scientific experimentation, the discipline of which Allan Franklin is one of the outstanding scholars and founders. Here, the central focus of the book is the contemporary shift in the norms of representation of experimental results in particle physics as well as the increasing role and drawbacks of statistical standards of acceptance for those results.

The Professor as Teacher: Allan Bloom, Wayne Booth, and the Tradition of Teaching at the University of Chicago.

ERIC Educational Resources Information Center

Wrightson, Katherine M.

1998-01-01

The University of Chicago (Illinois) has long emphasized teaching as a valued skill, fostering an image focused on the intellectual search for truth and transmission of intellectual values, a stand in opposition to popular relativist theories. Through the writings of Allan Bloom, Wayne Booth, and historical university documents, this model of…

Radial forcing and Edgar Allan Poe's lengthening pendulum

NASA Astrophysics Data System (ADS)

McMillan, Matthew; Blasing, David; Whitney, Heather M.

2013-09-01

Inspired by Edgar Allan Poe's The Pit and the Pendulum, we investigate a radially driven, lengthening pendulum. We first show that increasing the length of an undriven pendulum at a uniform rate does not amplify the oscillations in a manner consistent with the behavior of the scythe in Poe's story. We discuss parametric amplification and the transfer of energy (through the parameter of the pendulum's length) to the oscillating part of the system. In this manner, radial driving can easily and intuitively be understood, and the fundamental concept applied in many other areas. We propose and show by a numerical model that appropriately timed radial forcing can increase the oscillation amplitude in a manner consistent with Poe's story. Our analysis contributes a computational exploration of the complex harmonic motion that can result from radially driving a pendulum and sheds light on a mechanism by which oscillations can be amplified parametrically. These insights should prove especially valuable in the undergraduate physics classroom, where investigations into pendulums and oscillations are commonplace.

Improving Signal Detection using Allan and Theo Variances

NASA Astrophysics Data System (ADS)

Hardy, Andrew; Broering, Mark; Korsch, Wolfgang

2017-09-01

Precision measurements often deal with small signals buried within electronic noise. Extracting these signals can be enhanced through digital signal processing. Improving these techniques provide signal to noise ratios. Studies presently performed at the University of Kentucky are utilizing the electro-optic Kerr effect to understand cell charging effects within ultra-cold neutron storage cells. This work is relevant for the neutron electric dipole moment (nEDM) experiment at Oak Ridge National Laboratory. These investigations, and future investigations in general, will benefit from the illustrated improved analysis techniques. This project will showcase various methods for determining the optimum duration that data should be gathered for. Typically, extending the measuring time of an experimental run reduces the averaged noise. However, experiments also encounter drift due to fluctuations which mitigate the benefits of extended data gathering. Through comparing FFT averaging techniques, along with Allan and Theo variance measurements, quantifiable differences in signal detection will be presented. This research is supported by DOE Grants: DE-FG02-99ER411001, DE-AC05-00OR22725.

Allan Hills Pleistocene Ice Project (PIP)

NASA Astrophysics Data System (ADS)

Kurbatov, A.; Brook, E.; Campbell, S. W.; Conway, H.; Dunbar, N. W.; Higgins, J. A.; Iverson, N. A.; Kehrl, L. M.; McIntosh, W. C.; Spaulding, N. E.; Yan, Y.; Mayewski, P. A.

2016-12-01

A major international effort to identify at least 1.5 Ma old ice for paleoclimate reconstructions has successfully resulted in the selection of several potential drill sites in East Antarctica. At this point it is indisputable that the Antarctic ice sheet captures a continuous envinronmental record of the Earth that spans the Mid Pleistocene Transition (MPT). In addition to traditional ice coring approaches, the oldest ice can also be recovered in Antarctic Blue Ice Areas (BIA). We have already successfully demonstrated that the Allan Hills (AH) BIA captures a regional climate signal and robust record of 1Ma atmosphere that can be studied with a relatively uncomplicated logistical imprint and essentially unlimited sampling volume. The attractiveness of unlimited sampling of known age ice is the basis for the "ice park" concept proposed earlier by our research team. The idea is that, once the age of ice exposed along the flow line at the surface of BIA is mapped, it could be sampled for numerous research projects as needed. Here we propose an intermediate ( 1,150 m deep) ice core drill site, located only 240 km away from McMurdo base that will help to develop a, continuous, high quality regional paleoclimate record that is at least 1Ma old. We will introduce and discuss the glaciological settings, paleoclimate signals and possible limitations and advantages of the 1 Ma AH BIA regional paleoclimate record. The research was funded by NSF Division of Polar Programs.

Clues on Past Climatic Environments and Subsurface Flow in Mars from Aqueous Alteration Minerals Found in Nakhla and Allan Hills 84001 Meteorites

NASA Astrophysics Data System (ADS)

Trigo-Rodriguez, J. M.; Moyano-Cambero, C. E.; Donoso, J. A.; Benito-Moreno, M. I.; Alonso-Azcárate, J.

2018-04-01

The study of aqueous alteration minerals like Fe-Mg-Ca carbonates in Allan Hills 84001 or iddingsite and magnetite in Nakhla meteorite allow us to constrain their formation conditions and water availability at 4 and 1.3 Ga ago, respectively.

Ice dynamics of the Allan Hills meteorite concentration sites revealed by satellite aperture radar interferometry

NASA Astrophysics Data System (ADS)

Coren, F.; Delisle, G.; Sterzai, P.

2003-09-01

The ice flow conditions of a 100 x 100 km area of Victoria Land, Antarctica were analyzed with the synthetic aperture radar (SAR) technique. The area includes a number of meteorite concentration sites, in particular the Allan Hills ice fields. Regional ice flow velocities around the Mid- western and Near-western ice fields and the Allan Hills main ice field are shown to be 2.5 m yr-1. These sites are located on a horseshoe-shaped area that bounds an area characterized by higher ice flow velocities of up to 5 m yr-1. Meteorite find locations on the Elephant Moraine are located in this "high ice flow" area. The SAR derived digital elevation model (DEM) shows atypical low surface slopes for Antarctic conditions, which are the cause for the slow ice movements. Numerous ice rises in the area are interpreted to cap sub-ice obstacles, which were formed by tectonic processes in the past. The ice rises are considered to represent temporary features, which develop only during warm stages when the regional ice stand is lowered. Ice depressions, which develop in warm stages on the lee side of ice rises, may act as the sites of temporary build-up of meteorite concentrations, which turn inoperative during cold stages when the regional ice level rises and the ice rises disappear. Based on a simplified ice flow model, we argue that the regional ice flow in cold stages is reduced by a factor of at least 3.

Investigation of Allan variance for determining noise spectral forms with application to microwave radiometry

NASA Technical Reports Server (NTRS)

Stanley, William D.

1994-01-01

An investigation of the Allan variance method as a possible means for characterizing fluctuations in radiometric noise diodes has been performed. The goal is to separate fluctuation components into white noise, flicker noise, and random-walk noise. The primary means is by discrete-time processing, and the study focused primarily on the digital processes involved. Noise satisfying the requirements was generated by direct convolution, fast Fourier transformation (FFT) processing in the time domain, and FFT processing in the frequency domain. Some of the numerous results obtained are presented along with the programs used in the study.

Noble gases in twenty Yamato H-chondrites: Comparison with Allan Hills chondrites and modern falls

NASA Technical Reports Server (NTRS)

Loeken, TH.; Scherer, P.; Schultz, L.

1993-01-01

Concentration and isotopic composition of noble gases have been measured in 20 H-chrondrites found on the Yamato Mountains ice fields in Antarctica. The distribution of exposure ages as well as of radiogenic He-4 contents is similar to that of H-chrondrites collected at the Allan Hills site. Furthermore, a comparison of the noble gas record of Antarctic H-chrondrites and finds or falls from non-Antarctic areas gives no support to the suggestion that Antarctic H-chrondrites and modern falls derive from differing interplanetary meteorite populations.

On an Allan variance approach to classify VLBI radio-sources on the basis of their astrometric stability

NASA Astrophysics Data System (ADS)

Gattano, C.; Lambert, S.; Bizouard, C.

2017-12-01

In the context of selecting sources defining the celestial reference frame, we compute astrometric time series of all VLBI radio-sources from observations in the International VLBI Service database. The time series are then analyzed with Allan variance in order to estimate the astrometric stability. From results, we establish a new classification that takes into account the whole multi-time scales information. The algorithm is flexible on the definition of ``stable source" through an adjustable threshold.

Investigations into an unknown organism on the martian meteorite Allan Hills 84001

NASA Technical Reports Server (NTRS)

Steele, A.; Goddard, D. T.; Stapleton, D.; Toporski, J. K.; Peters, V.; Bassinger, V.; Sharples, G.; Wynn-Williams, D. D.; McKay, D. S.

2000-01-01

Examination of fracture surfaces near the fusion crust of the martian meteorite Allan Hills (ALH) 84001 have been conducted using scanning electron microscopy (SEM) and atomic force microscopy (AFM) and has revealed structures strongly resembling mycelium. These structures were compared with similar structures found in Antarctic cryptoendolithic communities. On morphology alone, we conclude that these features are not only terrestrial in origin but probably belong to a member of the Actinomycetales, which we consider was introduced during the Antarctic residency of this meteorite. If true, this is the first documented account of terrestrial microbial activity within a meteorite from the Antarctic blue ice fields. These structures, however, do not bear any resemblance to those postulated to be martian biota, although they are a probable source of the organic contaminants previously reported in this meteorite.

Application of Fast Dynamic Allan Variance for the Characterization of FOGs-Based Measurement While Drilling.

PubMed

Wang, Lu; Zhang, Chunxi; Gao, Shuang; Wang, Tao; Lin, Tie; Li, Xianmu

2016-12-07

The stability of a fiber optic gyroscope (FOG) in measurement while drilling (MWD) could vary with time because of changing temperature, high vibration, and sudden power failure. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool that could represent the non-stationary behavior of the gyroscope signal. Since the normal DAVAR takes too long to deal with long time series, a fast DAVAR algorithm has been developed to accelerate the computation speed. However, both the normal DAVAR algorithm and the fast algorithm become invalid for discontinuous time series. What is worse, the FOG-based MWD underground often keeps working for several days; the gyro data collected aboveground is not only very time-consuming, but also sometimes discontinuous in the timeline. In this article, on the basis of the fast algorithm for DAVAR, we make a further advance in the fast algorithm (improved fast DAVAR) to extend the fast DAVAR to discontinuous time series. The improved fast DAVAR and the normal DAVAR are used to responsively characterize two sets of simulation data. The simulation results show that when the length of the time series is short, the improved fast DAVAR saves 78.93% of calculation time. When the length of the time series is long ( 6 × 10 5 samples), the improved fast DAVAR reduces calculation time by 97.09%. Another set of simulation data with missing data is characterized by the improved fast DAVAR. Its simulation results prove that the improved fast DAVAR could successfully deal with discontinuous data. In the end, a vibration experiment with FOGs-based MWD has been implemented to validate the good performance of the improved fast DAVAR. The results of the experience testify that the improved fast DAVAR not only shortens computation time, but could also analyze discontinuous time series.

Application of Fast Dynamic Allan Variance for the Characterization of FOGs-Based Measurement While Drilling

PubMed Central

Wang, Lu; Zhang, Chunxi; Gao, Shuang; Wang, Tao; Lin, Tie; Li, Xianmu

2016-01-01

The stability of a fiber optic gyroscope (FOG) in measurement while drilling (MWD) could vary with time because of changing temperature, high vibration, and sudden power failure. The dynamic Allan variance (DAVAR) is a sliding version of the Allan variance. It is a practical tool that could represent the non-stationary behavior of the gyroscope signal. Since the normal DAVAR takes too long to deal with long time series, a fast DAVAR algorithm has been developed to accelerate the computation speed. However, both the normal DAVAR algorithm and the fast algorithm become invalid for discontinuous time series. What is worse, the FOG-based MWD underground often keeps working for several days; the gyro data collected aboveground is not only very time-consuming, but also sometimes discontinuous in the timeline. In this article, on the basis of the fast algorithm for DAVAR, we make a further advance in the fast algorithm (improved fast DAVAR) to extend the fast DAVAR to discontinuous time series. The improved fast DAVAR and the normal DAVAR are used to responsively characterize two sets of simulation data. The simulation results show that when the length of the time series is short, the improved fast DAVAR saves 78.93% of calculation time. When the length of the time series is long (6×105 samples), the improved fast DAVAR reduces calculation time by 97.09%. Another set of simulation data with missing data is characterized by the improved fast DAVAR. Its simulation results prove that the improved fast DAVAR could successfully deal with discontinuous data. In the end, a vibration experiment with FOGs-based MWD has been implemented to validate the good performance of the improved fast DAVAR. The results of the experience testify that the improved fast DAVAR not only shortens computation time, but could also analyze discontinuous time series. PMID:27941600

Observation, Inference, and Imagination: Elements of Edgar Allan Poe's Philosophy of Science

NASA Astrophysics Data System (ADS)

Gelfert, Axel

2014-03-01

Edgar Allan Poe's standing as a literary figure, who drew on (and sometimes dabbled in) the scientific debates of his time, makes him an intriguing character for any exploration of the historical interrelationship between science, literature and philosophy. His sprawling `prose-poem' Eureka (1848), in particular, has sometimes been scrutinized for anticipations of later scientific developments. By contrast, the present paper argues that it should be understood as a contribution to the raging debates about scientific methodology at the time. This methodological interest, which is echoed in Poe's `tales of ratiocination', gives rise to a proposed new mode of—broadly abductive—inference, which Poe attributes to the hybrid figure of the `poet-mathematician'. Without creative imagination and intuition, Science would necessarily remain incomplete, even by its own standards. This concern with imaginative (abductive) inference ties in nicely with his coherentism, which grants pride of place to the twin virtues of Simplicity and Consistency, which must constrain imagination lest it degenerate into mere fancy.

Allan Hills 76005 Polymict Eucrite Pairing Group: Curatorial and Scientific Update on a Jointly Curated Meteorite

NASA Technical Reports Server (NTRS)

Righter, K.

2011-01-01

Allan Hills 76005 (or 765) was collected by the joint US-Japan field search for meteorites in 1976-77. It was described in detail as "pale gray in color and consists of finely divided macrocrystalline pyroxene-rich matrix that contains abundant clastic fragments: (1) Clasts of white, plagioclase-rich rocks. (2) Medium-gray, partly devitrified, cryptocrystalline. (3) Monomineralic fragments and grains of pyroxene, plagioclases, oxide minerals, sulfides, and metal. In overall appearance it is very similar to some lunar breccias." Subsequent studies found a great diversity of basaltic clast textures and compositions, and therefore it is best classified as a polymict eucrite. Samples from the 1976-77, 77-78, and 78-79 field seasons (76, 77, and 78 prefixes) were split between US and Japan (NIPR). The US specimens are currently at NASA-JSC, Smithsonian Institution, or the Field Museum in Chicago. After this initial finding of ALH 76005, the next year s team recovered one additional mass ALH 77302, and then four additional masses were found during the third season ALH 78040 and ALH 78132, 78158 and 78165. The joint US-Japan collection effort ended after three years and the US began collecting in the Trans-Antarctic Mountains with the 1979-80 and subsequent field seasons. ALH 79017 and ALH 80102 were recovered in these first two years, and then in 1981-82 field season, 6 additional masses were recovered from the Allan Hills. Of course it took some time to establish pairing of all of these specimens, but altogether the samples comprise 4292.4 g of material. Here will be summarized the scientific findings as well as some curatorial details of how specimens have been subdivided and allocated for study. A detailed summary is also presented on the NASA-JSC curation webpage for the HED meteorite compendium.

THE DEAD-LIVING-MOTHER: MARIE BONAPARTE'S INTERPRETATION OF EDGAR ALLAN POE'S SHORT STORIES.

PubMed

Obaid, Francisco Pizarro

2016-06-01

Princess Marie Bonaparte is an important figure in the history of psychoanalysis, remembered for her crucial role in arranging Freud's escape to safety in London from Nazi Vienna, in 1938. This paper connects us to Bonaparte's work on Poe's short stories. Founded on concepts of Freudian theory and an exhaustive review of the biographical facts, Marie Bonaparte concluded that the works of Edgar Allan Poe drew their most powerful inspirational force from the psychological consequences of the early death of the poet's mother. In Bonaparte's approach, which was powerfully influenced by her recognition of the impact of the death of her own mother when she was born-an understanding she gained in her analysis with Freud-the thesis of the dead-living-mother achieved the status of a paradigmatic key to analyze and understand Poe's literary legacy. This paper explores the background and support of this hypothesis and reviews Bonaparte's interpretation of Poe's most notable short stories, in which extraordinary female figures feature in the narrative.

The final days of Edgar Allan Poe: clues to an old mystery using 21st century medical science.

PubMed

Francis, Roger A

This study examines all documented information regarding the final days and death of Edgar Allan Poe (1809-1849), in an attempt to determine the most likely cause of death of the American poet, short story writer, and literary critic. Information was gathered from letters, newspaper accounts, and magazine articles written during the period after Poe's death, and also from biographies and medical journal articles written up until the present. A chronology of Poe's final days was constructed, and this was used to form a differential diagnosis of possible causes of death. Death theories over the last 160 years were analyzed using this information. This analysis, along with a review of Poe's past medical history, would seem to support an alcohol-related cause of death.

Application of the Allan Variance to Time Series Analysis in Astrometry and Geodesy: A Review.

PubMed

Malkin, Zinovy

2016-04-01

The Allan variance (AVAR) was introduced 50 years ago as a statistical tool for assessing the frequency standards deviations. For the past decades, AVAR has increasingly been used in geodesy and astrometry to assess the noise characteristics in geodetic and astrometric time series. A specific feature of astrometric and geodetic measurements, as compared with clock measurements, is that they are generally associated with uncertainties; thus, an appropriate weighting should be applied during data analysis. In addition, some physically connected scalar time series naturally form series of multidimensional vectors. For example, three station coordinates time series X, Y, and Z can be combined to analyze 3-D station position variations. The classical AVAR is not intended for processing unevenly weighted and/or multidimensional data. Therefore, AVAR modifications, namely weighted AVAR (WAVAR), multidimensional AVAR (MAVAR), and weighted multidimensional AVAR (WMAVAR), were introduced to overcome these deficiencies. In this paper, a brief review is given of the experience of using AVAR and its modifications in processing astrogeodetic time series.

Twenty-Five Years of Applications of the Modified Allan Variance in Telecommunications.

PubMed

Bregni, Stefano

2016-04-01

The Modified Allan Variance (MAVAR) was originally defined in 1981 for measuring frequency stability in precision oscillators. Due to its outstanding accuracy in discriminating power-law noise, it attracted significant interest among telecommunications engineers since the early 1990s, when it was approved as a standard measure in international standards, redressed as Time Variance (TVAR), for specifying the time stability of network synchronization signals and of equipment clocks. A dozen years later, the usage of MAVAR was also introduced for Internet traffic analysis to estimate self-similarity and long-range dependence. Further, in this field, it demonstrated superior accuracy and sensitivity, better than most popular tools already in use. This paper surveys the last 25 years of progress in extending the field of application of the MAVAR in telecommunications. First, the rationale and principles of the MAVAR are briefly summarized. Its adaptation as TVAR for specification of timing stability is presented. The usage of MAVAR/TVAR in telecommunications standards is reviewed. Examples of measurements on real telecommunications equipment clocks are presented, providing an overview on their actual performance in terms of MAVAR. Moreover, applications of MAVAR to network traffic analysis are surveyed. The superior accuracy of MAVAR in estimating long-range dependence is emphasized by highlighting some remarkable practical examples of real network traffic analysis.

Further Insights into the Allan-Herndon-Dudley Syndrome: Clinical and Functional Characterization of a Novel MCT8 Mutation.

PubMed

Armour, Christine M; Kersseboom, Simone; Yoon, Grace; Visser, Theo J

2015-01-01

Mutations in the thyroid hormone (TH) transporter MCT8 have been identified as the cause for Allan-Herndon-Dudley Syndrome (AHDS), characterized by severe psychomotor retardation and altered TH serum levels. Here we report a novel MCT8 mutation identified in 4 generations of one family, and its functional characterization. Proband and family members were screened for 60 genes involved in X-linked cognitive impairment and the MCT8 mutation was confirmed. Functional consequences of MCT8 mutations were studied by analysis of [125I]TH transport in fibroblasts and transiently transfected JEG3 and COS1 cells, and by subcellular localization of the transporter. The proband and a male cousin demonstrated clinical findings characteristic of AHDS. Serum analysis showed high T3, low rT3, and normal T4 and TSH levels in the proband. A MCT8 mutation (c.869C>T; p.S290F) was identified in the proband, his cousin, and several female carriers. Functional analysis of the S290F mutant showed decreased TH transport, metabolism and protein expression in the three cell types, whereas the S290A mutation had no effect. Interestingly, both uptake and efflux of T3 and T4 was impaired in fibroblasts of the proband, compared to his healthy brother. However, no effect of the S290F mutation was observed on TH efflux from COS1 and JEG3 cells. Immunocytochemistry showed plasma membrane localization of wild-type MCT8 and the S290A and S290F mutants in JEG3 cells. We describe a novel MCT8 mutation (S290F) in 4 generations of a family with Allan-Herndon-Dudley Syndrome. Functional analysis demonstrates loss-of-function of the MCT8 transporter. Furthermore, our results indicate that the function of the S290F mutant is dependent on cell context. Comparison of the S290F and S290A mutants indicates that it is not the loss of Ser but its substitution with Phe, which leads to S290F dysfunction.

Further Insights into the Allan-Herndon-Dudley Syndrome: Clinical and Functional Characterization of a Novel MCT8 Mutation

PubMed Central

Yoon, Grace; Visser, Theo J.

2015-01-01

Background Mutations in the thyroid hormone (TH) transporter MCT8 have been identified as the cause for Allan-Herndon-Dudley Syndrome (AHDS), characterized by severe psychomotor retardation and altered TH serum levels. Here we report a novel MCT8 mutation identified in 4 generations of one family, and its functional characterization. Methods Proband and family members were screened for 60 genes involved in X-linked cognitive impairment and the MCT8 mutation was confirmed. Functional consequences of MCT8 mutations were studied by analysis of [125I]TH transport in fibroblasts and transiently transfected JEG3 and COS1 cells, and by subcellular localization of the transporter. Results The proband and a male cousin demonstrated clinical findings characteristic of AHDS. Serum analysis showed high T3, low rT3, and normal T4 and TSH levels in the proband. A MCT8 mutation (c.869C>T; p.S290F) was identified in the proband, his cousin, and several female carriers. Functional analysis of the S290F mutant showed decreased TH transport, metabolism and protein expression in the three cell types, whereas the S290A mutation had no effect. Interestingly, both uptake and efflux of T3 and T4 was impaired in fibroblasts of the proband, compared to his healthy brother. However, no effect of the S290F mutation was observed on TH efflux from COS1 and JEG3 cells. Immunocytochemistry showed plasma membrane localization of wild-type MCT8 and the S290A and S290F mutants in JEG3 cells. Conclusions We describe a novel MCT8 mutation (S290F) in 4 generations of a family with Allan-Herndon-Dudley Syndrome. Functional analysis demonstrates loss-of-function of the MCT8 transporter. Furthermore, our results indicate that the function of the S290F mutant is dependent on cell context. Comparison of the S290F and S290A mutants indicates that it is not the loss of Ser but its substitution with Phe, which leads to S290F dysfunction. PMID:26426690

Balancing between sensitization and repression: the role of opium in the life and art of Edgar Allan Poe and Samuel Taylor Coleridge.

PubMed

Iszáj, Fruzsina; Demetrovics, Zsolt

2011-01-01

The creative process contains both conscious and unconscious work. Therefore, artists have to face their unconscious processes and work with emotional material that is difficult to keep under control in the course of artistic creation. Bringing these contents of consciousness to the surface needs special sensitivity and special control functions while working with them. Considering these mechanisms, psychoactive substance can serve a double function in the case of artists. On the one hand, chemical substances may enhance the artists' sensitivity. On the other hand, they can help moderate the hypersensitivity and repress extreme emotions and burdensome contents of consciousness. The authors posit how the use of opiates could have influenced the life and creative work of Edgar Allan Poe and Samuel Taylor Coleridge.

Fine-Grained Rims in the Allan Hills 81002 and Lewis Cliff 90500 CM2 Meteorites: Their Origin and Modification

NASA Technical Reports Server (NTRS)

Hua, X.; Wang, J.; Buseck, P. R.

2002-01-01

Antarctic CM meteorites Allan Hills (ALH) 8 1002 and Lewis Cliff (LEW) 90500 contain abundant fine-grained rims (FGRs) that surround a variety of coarse-grained objects. FGRs from both meteorites have similar compositions and petrographic features, independent of their enclosed objects. The FGRs are chemically homogeneous at the 10 m scale for major and minor elements and at the 25 m scale for trace elements. They display accretionary features and contain large amounts of volatiles, presumably water. They are depleted in Ca, Mn, and S but enriched in P. All FGRs show a slightly fractionated rare earth element (REE) pattern, with enrichments of Gd and Yb and depletion of Er. Gd is twice as abundant as Er. Our results indicate that those FGRs are not genetically related to their enclosed cores. They were sampled from a reservoir of homogeneously mixed dust, prior to accretion to their parent body. The rim materials subsequently experienced aqueous alteration under identical conditions. Based on their mineral, textural, and especially chemical similarities, we conclude that ALH 8 1002 and LEW 90500 likely have a similar or identical source.

The first description of the complete natural history of uveal melanoma by two Scottish surgeons, Allan Burns and James Wardrop.

PubMed

Kivelä, Tero T

2018-03-01

James Wardrop (1782-1869), a young Scottish surgeon and an early ophthalmologist in Edinburgh, is credited for describing in 1809 retinoblastoma as an entity in his treatise 'Observations on Fungus Haematodes or Soft Cancer'. His treatise also reveals that Allan Burns (1781-1813), another young Scottish surgeon and anatomist, had invited Wardrop to assist in enucleating an eye from a 41-year-old Glasgow woman who, in retrospect, had a uveal melanoma. Her eye had become blind 4 months after symptoms of exudative retinal detachment had appeared, and it had become painful after a further 2-4 months. The tumour eventually perforated the sclera, and she died within a year thereafter of hepatic metastases. Burns and Wardrop went on to publish detailed parallel accounts of the symptoms, signs, ophthalmic pathology and post-mortem findings regarding the primary, recurrent and metastatic tumour. Burns may have performed the post-mortem after exhuming the body, a common occurrence in early 19th Century Scotland, a thriving hub for teaching morbid anatomy to young surgeons at the time. © 2017 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Noble gas isotopic composition, cosmic ray exposure history, and terrestrial age of the meteorite Allan Hills A81005 from the moon

NASA Astrophysics Data System (ADS)

Eugster, O.; Geiss, J.; Kraehenbuehl, U.; Niedermann, S.

1986-06-01

A comprehensive study of the elemental and isotopic abundances of the noble gases He, Ne, Ar, Kr, and Xe in the meteorite Allan Hills A81005 from the moon is presented. In addition to a bulk sample, five grain-size fractions were analyzed. Chemical abundances relevant to the interpretation of the cosmic-ray-produced noble gases were determined and indicate that the grain size fractions are chemically uniform. Except for the fact that the trapped noble gas concentrations appear to be grain size correlated, the isotopic and elemental pattern of the trapped solar wind noble gases in A81005 are very similar to those observed in lunar soils and breccias. The A81005 material resided during (580 + or - 180) Myr in the nuclear active zone of the lunar regolith at an average shielding depth of about 40 g/sq cm. From literature data, it is concluded that the moon-earth transit time lasted less than a few million years. Finally, A81005 was captured by the earth more than 140,000 years ago, as indicated by the abundance of cosmic-ray-produced Kr-81.

COORDINATED ANALYSES OF PRESOLAR GRAINS IN THE ALLAN HILLS 77307 AND QUEEN ELIZABETH RANGE 99177 METEORITES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nguyen, Ann N.; Nittler, Larry R.; Alexander, Conel M. O'D.

2010-08-10

We report the identification of presolar silicates ({approx}177 ppm), presolar oxides ({approx}11 ppm), and one presolar SiO{sub 2} grain in the Allan Hills (ALHA) 77307 chondrite. Three grains having Si-isotopic compositions similar to SiC X and Z grains were also identified, though the mineral phases are unconfirmed. Similar abundances of presolar silicates ({approx}152 ppm) and oxides ({approx}8 ppm) were also uncovered in the primitive CR chondrite Queen Elizabeth Range (QUE) 99177, along with 13 presolar SiC grains and one presolar silicon nitride. The O-isotopic compositions of the presolar silicates and oxides indicate that most of the grains condensed in low-massmore » red giant and asymptotic giant branch stars. Interestingly, unlike presolar oxides, few presolar silicate grains have isotopic compositions pointing to low-metallicity, low-mass stars (Group 3). The {sup 18}O-rich (Group 4) silicates, along with the few Group 3 silicates that were identified, likely have origins in supernova outflows. This is supported by their O- and Si-isotopic compositions. Elemental compositions for 74 presolar silicate grains were determined by scanning Auger spectroscopy. Most of the grains have non-stoichiometric elemental compositions inconsistent with pyroxene or olivine, the phases commonly used to fit astronomical spectra, and have comparable Mg and Fe contents. Non-equilibrium condensation and/or secondary alteration could produce the high Fe contents. Transmission electron microscopic analysis of three silicate grains also reveals non-stoichiometric compositions, attributable to non-equilibrium or multistep condensation, and very fine scale elemental heterogeneity, possibly due to subsequent annealing. The mineralogies of presolar silicates identified in meteorites thus far seem to differ from those in interplanetary dust particles.« less

DRDC Technical Stream Integrated Capabilities and Vision

DTIC Science & Technology

2011-09-01

Brenda Fraser Allan Keefe Nada Pavlovic Doug Saunders Phil Terhaar Defence R&D Canada Technical Memorandum DRDC Toronto...Beechinor Hamid Boland Brenda Fraser Allan Keefe Nada Pavlovic Doug Saunders Phil Terhaar Defence R&D Canada – Toronto...Technical Memorandum DRDC Toronto TM 2011-017 September 2011 Principal Author Original signed by Allan Keefe Allan Keefe Technical

Carbonates in the Martian meteorite Allan Hills 84001 formed at 18 ± 4 °C in a near-surface aqueous environment

PubMed Central

Halevy, Itay; Fischer, Woodward W.; Eiler, John M.

2011-01-01

Despite evidence for liquid water at the surface of Mars during the Noachian epoch, the temperature of early aqueous environments has been impossible to establish, raising questions of whether the surface of Mars was ever warmer than today. We address this problem by determining the precipitation temperature of secondary carbonate minerals preserved in the oldest known sample of Mars’ crust—the approximately 4.1 billion-year-old meteorite Allan Hills 84001 (ALH84001). The formation environment of these carbonates, which are constrained to be slightly younger than the crystallization age of the rock (i.e., 3.9 to 4.0 billion years), has been poorly understood, hindering insight into the hydrologic and carbon cycles of earliest Mars. Using “clumped” isotope thermometry we find that the carbonates in ALH84001 precipitated at a temperature of approximately 18 °C, with water and carbon dioxide derived from the ancient Martian atmosphere. Furthermore, covarying carbonate carbon and oxygen isotope ratios are constrained to have formed at constant, low temperatures, pointing to deposition from a gradually evaporating, subsurface water body—likely a shallow aquifer (meters to tens of meters below the surface). Despite the mild temperatures, the apparently ephemeral nature of water in this environment leaves open the question of its habitability. PMID:21969543

77 FR 27357 - IFR Altitudes; Miscellaneous Amendments

Federal Register 2010, 2011, 2012, 2013, 2014

2012-05-10

... Hygen, CO FIX *Allan, CO FIX **13500 *16000--MRA *15400--MCA ALLAN, CO FIX, NW BND **12900--MOCA *CHART... *Allan, CO FIX Laramie, WY VOR/DME..... 16000 *16000--MRA Sec. 95.6106 VOR Federal Airway V106 Is Amended... in Part Olympia, WA VORTAC *Carro, WA FIX **4000 *4000--MRA **2000--MOCA *CARRO, WA FIX Diggn, WA FIX...

Bennett, Bloom and Boyer: Toward a Critical Discussion.

ERIC Educational Resources Information Center

Reitz, Charles

An overview is provided of the educational philosophies of Allan Bloom, Lynne V. Cheney, William Bennett, and Ernest Boyer, with special focus on their political underpinnings. The essay begins with an examination of the issues discussed in "The Closing of the American Mind," by Allan Bloom. Concern and disagreement is expressed about:…

Radioactivities in returned lunar materials and in meteorites

NASA Technical Reports Server (NTRS)

Fireman, E. L.

1984-01-01

Carbon 14 terrestial ages were determined with low level minicomputers and accelerator mass spectrometry on 1 Yamato and 18 Allan Hills and nearby sited meteorites. Techniques for an accelerator mass spectrometer which make C(14) measurements on small samples were developed. Also Be(10) concentrations were measured in Byrd core and Allan Hills ice samples.

40th Annual Armament Systems: Guns-Ammunition-Rockets-Missiles Conference and Exhibition

DTIC Science & Technology

2005-04-28

Session: Medium Caliber System Oerlikon Ammunition for New Defense Environment, Mr. Allan N. Buckley, BTECH Oerlikon Contraves Pyrotec AG Multi...Environment Mr. Allan N. Buckley, BTECH Oerlikon Contraves Pyrotec AG Force Protection - Multi Mission Vehicle Armament & Air Burst Munition for...determine homogeneity – Propellant contains ~3% by weight of FS grains to adjust K

Neuronal 3',3,5-triiodothyronine (T3) uptake and behavioral phenotype of mice deficient in Mct8, the neuronal T3 transporter mutated in Allan-Herndon-Dudley syndrome.

PubMed

Wirth, Eva K; Roth, Stephan; Blechschmidt, Cristiane; Hölter, Sabine M; Becker, Lore; Racz, Ildiko; Zimmer, Andreas; Klopstock, Thomas; Gailus-Durner, Valerie; Fuchs, Helmut; Wurst, Wolfgang; Naumann, Thomas; Bräuer, Anja; de Angelis, Martin Hrabé; Köhrle, Josef; Grüters, Annette; Schweizer, Ulrich

2009-07-29

Thyroid hormone transport into cells requires plasma membrane transport proteins. Mutations in one of these, monocarboxylate transporter 8 (MCT8), have been identified as underlying cause for the Allan-Herndon-Dudley syndrome, an X-linked mental retardation in which the patients also present with abnormally high 3',3,5-triiodothyronine (T(3)) plasma levels. Mice deficient in Mct8 replicate the thyroid hormone abnormalities observed in the human condition. However, no neurological deficits have been described in mice lacking Mct8. Therefore, we subjected Mct8-deficient mice to a comprehensive immunohistochemical, neurological, and behavioral screen. Several behavioral abnormalities were found in the mutants. Interestingly, some of these behavioral changes are compatible with hypothyroidism, whereas others rather indicate hyperthyroidism. We thus hypothesized that neurons exclusively dependent on Mct8 are in a hypothyroid state, whereas neurons expressing other T(3) transporters become hyperthyroid, if they are exposed directly to the high plasma T(3). The majority of T(3) uptake in primary cortical neurons is mediated by Mct8, but pharmacological inhibition suggested functional expression of additional T(3) transporter classes. mRNAs encoding six T(3) transporters, including L-type amino acid transporters (LATs), were coexpressed with Mct8 in isolated neurons. We then demonstrated Lat2 expression in cultured neurons and throughout murine brain development. In contrast, LAT2 is expressed in microglia in the developing human brain during gestation, but not in neurons. We suggest that lack of functional complementation by alternative thyroid hormone transporters in developing human neurons precipitates the devastating neurodevelopmental phenotype in MCT8-deficient patients, whereas Mct8-deficient mouse neurons are functionally complemented by other transporters, for possibly Lat2.

Antarctic Meteorite Location Map Series

NASA Technical Reports Server (NTRS)

Schutt, John (Editor); Fessler, Brian (Editor); Cassidy, William (Editor)

1989-01-01

Antarctica has been a prolific source of meteorites since meteorite concentrations were discovered in 1969. The Antarctic Search For Meteorites (ANSMET) project has been active over much of the Trans-Antarctic Mountain Range. The first ANSMET expedition (a joint U.S.-Japanese effort) discovered what turned out to be a significant concentration of meteorites at the Allan Hills in Victoria Land. Later reconnaissance in this region resulted in the discovery of meteorite concentrations on icefields to the west of the Allan Hills, at Reckling Moraine, and Elephant Moraine. Antarctic meteorite location maps (reduced versions) of the Allan Hills main, near western, middle western, and far western icefields and the Elephant Moraine icefield are presented. Other Antarctic meteorite location maps for the specimens found by the ANSMET project are being prepared.

The Problem of Disobedience and the Intelligence Community

DTIC Science & Technology

1990-06-01

focus on the technological and analytical aspects of the profession. Despite some highly successful but less-than- savory operations in the past,3 there... Allan Bloom, The Closing of the American Mind (New York: Simon & Schuster, 1987), p. 26. 23. Thomas B. Allen and Norman Polmar, Merchants of Treason...Waldo Emerson. New York: Modern Library, 1940. Bloom, Allan . The Closing of the American Mind. New York: Simon & Schuster, 1942. Carter, Jimmy

Temperature variation effects on stochastic characteristics for low-cost MEMS-based inertial sensor error

NASA Astrophysics Data System (ADS)

El-Diasty, M.; El-Rabbany, A.; Pagiatakis, S.

2007-11-01

We examine the effect of varying the temperature points on MEMS inertial sensors' noise models using Allan variance and least-squares spectral analysis (LSSA). Allan variance is a method of representing root-mean-square random drift error as a function of averaging times. LSSA is an alternative to the classical Fourier methods and has been applied successfully by a number of researchers in the study of the noise characteristics of experimental series. Static data sets are collected at different temperature points using two MEMS-based IMUs, namely MotionPakII and Crossbow AHRS300CC. The performance of the two MEMS inertial sensors is predicted from the Allan variance estimation results at different temperature points and the LSSA is used to study the noise characteristics and define the sensors' stochastic model parameters. It is shown that the stochastic characteristics of MEMS-based inertial sensors can be identified using Allan variance estimation and LSSA and the sensors' stochastic model parameters are temperature dependent. Also, the Kaiser window FIR low-pass filter is used to investigate the effect of de-noising stage on the stochastic model. It is shown that the stochastic model is also dependent on the chosen cut-off frequency.

Quality of water in the White River and Lake Tapps, Pierce County, Washington, May-December 2010

USGS Publications Warehouse

Embrey, S.S.; Wagner, R.J.; Huffman, R.L.; Vanderpool-Kimura, A. M.; Foreman, J.R.

2012-01-01

Water samples collected at the Allan Yorke, Snag Island, and Lake Outlet study sites were screened for the presence of more than 250 organic chemicals. A total of 14 compounds were detected in trace amounts (or determined to be present) at one or more of the 3 sites. The Allan Yorke site had 9 detections, the Snag Island site had 10 detections, and the Lake Outlet site had 5 detections of compounds mostly belonging to the group of wastewater indicator chemicals. Compounds detected (or with verified presence) at all three sites included the herbicide 2,4-D, the insecticide and mosquito repellant DEET, the herbicide fluridone used for Eurasian watermilfoil eradication, and the herbicide prometon. The largest concentrations of these compounds were in samples from the Allan Yorke site; the lowest concentrations were from the Lake Outlet site.

MHD memes

NASA Astrophysics Data System (ADS)

Dewar, R. L.; Mills, R.; Hole, M. J.

2009-05-01

The celebration of Allan Kaufman's 80th birthday was an occasion to reflect on a career that has stimulated the mutual exchange of ideas (or memes in the terminology of Richard Dawkins) between many researchers. This paper will revisit a meme Allan encountered in his early career in magnetohydrodynamics, the continuation of a magnetohydrodynamic mode through a singularity, and will also mention other problems where Allan's work has had a powerful cross-fertilizing effect in plasma physics and other areas of physics and mathematics. To resolve the continuation problem we regularize the Newcomb equation, solve it in terms of Legendre functions of imaginary argument, and define the small weak solutions of the Newcomb equation as generalized functions in the manner of Lighthill, i.e. via a limiting sequence of analytic functions that connect smoothly across the singularity.

Army Transformaton: A View from the U.S. Army War College

DTIC Science & Technology

2001-07-01

military, see particularly Allan R. Millett, The General: Robert L . Bullard and Officership in the United States Army, 1881-1925, Westport, CT: Greenwood...Westport, CT: Greenwood, 1986, p. 182. 2. Captain Carl Reichman, “In Pace Para Bellum,” Infantry Journal, Vol. II, January 1906, p. 5, quoted in James L ...United States Army, enlarged edition, Bloomington: Indiana University Press, 1984, pp. 265-354; Allan R. Millett, The General: Robert L . Bullard and

50 Div in Normandy: A Critical Analysis of the British 50th (Northumbrian) Division on D-Day and in the Battle of Normandy

DTIC Science & Technology

2007-12-14

University Press, 1997), 90-92. 5House, 47-48. 6Kier, 89-90. 7Brian Bond and Williamson Murray, The British Armed Forces, 1918-39 in Allan R. Millet ...Figure 5. The German Defenses on June 6, 1944. nage, Jean -Pierre Benamou, BSource: Georges Ber ernard Crochet, François de Lannoy, Laurent Mari, and...Murray, “British Military Effectiveness in the Second World War” Military Effectiveness, Vol. 3, ed. Allan R. Millet and Williamson Murray (Boston

DSN system performance test Doppler noise models; noncoherent configuration

NASA Technical Reports Server (NTRS)

Bunce, R.

1977-01-01

The newer model for variance, the Allan technique, now adopted for testing, is analyzed in the subject mode. A model is generated (including considerable contribution from the station secondary frequency standard), and rationalized with existing data. The variance model is definitely sound; the Allan technique mates theory and measure. The mean-frequency model is an estimate; this problem is yet to be rigorously resolved. The unaltered defining expressions are noncovergent, and the observed mean is quite erratic.

Autonomous cryogenic sapphire oscillators employing low vibration pulse-tube cryocoolers at NMIJ

NASA Astrophysics Data System (ADS)

Ikegami, Takeshi; Watabe, Ken-ichi; Yanagimachi, Shinya; Takamizawa, Akifumi; Hartnett, John G.

2016-06-01

Two liquid-helium-cooled cryogenic sapphire-resonator oscillators (CSOs), have been modified to operate using cryo-refrigerators and low-vibration cryostats. The Allan deviation of the first CSO was evaluated to be better than 2 x 10-15 for averaging times of 1 s to 30 000 s, which is better than that of the original liquid helium cooled CSO. The Allan deviation of the second CSO is better than 4 x 10-15 from 1 s to 6 000 s averaging time.

Waking the Sleeping Giant at Pearl Harbor: A Case for Intelligence and Operations Fusion

DTIC Science & Technology

2013-05-23

York: Random House Inc., 2002), 7. 9Allan R. Millet and Peter Maslowski, For the Common Defense A Military History of the United States of America...the complexity of a major war.”40 37Keegan, Intelligence in War, 188-89. 38Ball, Of Responsible Command, 189; Allan R. Millet & Peter Maslowski...65Gole, The Road to Rainbow, 114; Miller, War Plan Orange, 270; Millet and Maslowski, For the Common Defense, 418; Ross, U.S. War Plans 1938-1945, 55

Evaluation of Effect of Postoperative Wound Drainage Reinfusion Using the Solcotrans Orthopaedic Drainage/Reinfusion System in Reducing the Need for Whole Blood Transfusion (HSC)

DTIC Science & Technology

1991-03-01

REINFUSION SYSTEM IN REDUCING THE NEED FOR WHOLE BLOOD TRANSFUSION (HSC) PRINCIPAL INVESTIGATOR: Allan L. Bucknell, M.D. AUTHORS: Michael B. Simpson, M.D...einfysion SVt8T in Reducing the Need for whole Blood rans uson , 61102A Allan L. Bucknell, M.D.; Michael B. Simpson, M.D. 3MI61102BS12.ZZ Kevin P...for transfusion. J Bone Joint Suig. 1987; 6,QA:319). 3. Tlhomson JD), C al laghan JJ, Savory C’G, Stanton RP, Pierce RN. P’rior deposition of

The Effects of Laser Phase Noise on Laser Radar Performance

DTIC Science & Technology

1992-12-01

Laboratory 5. Figure 3 shows Allan variance plots of the above ultrastable C02 laser which has an open Fabry - Perot cavity 5. The open and solid circles...the same measurement time -r) by more than 10 dB. Therefore, the root Allan variance for the Fabry - Perot cavity ultrastable C02 laser can be...variance so that the SSB phase noise for the Fabry - Perot cavity ultrastable CO 2 laser is about 20 dB (because of the squaring operation) below that of the

Psychophysics of associative learning: Quantitative properties of subjective contingency.

PubMed

Maia, Susana; Lefèvre, Françoise; Jozefowiez, Jérémie

2018-01-01

Allan and collaborators (Allan, Hannah, Crump, & Siegel, 2008; Allan, Siegel, & Tangen, 2005; Siegel, Allan, Hannah, & Crump, 2009) recently proposed to apply signal detection theory to the analysis of contingency judgment tasks. When exposed to a flow of stimuli, participants are asked to judge whether there is a contingent relation between a cue and an outcome, that is, whether the subjective cue-outcome contingency exceeds a decision threshold. In this context, we tested the following hypotheses regarding the relation between objective and subjective cue-outcome contingency: (a) The underlying distributions of subjective cue-outcome contingency are Gaussian; (b) The mean distribution of subjective contingency is a linear function of objective cue-outcome contingency; and (c) The variance in the distribution of subjective contingency is constant. The hypotheses were tested by combining a streamed-trial contingency assessment task with a confidence rating procedure. Participants were exposed to rapid flows of stimuli at the end of which they had to judge whether an outcome was more (Experiment 1) or less (Experiment 2) likely to appear following a cue and how sure they were of their judgment. We found that although Hypothesis A seems reasonable, Hypotheses B and C were not. Regarding Hypothesis B, participants were more sensitive to positive than to negative contingencies. Regarding Hypothesis C, the perceived cue-outcome contingency became more variable when the contingency became more positive or negative, but only to a slight extent. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Optical frequency transfer via a 660 km underground fiber link using a remote Brillouin amplifier.

PubMed

Raupach, S M F; Koczwara, A; Grosche, G

2014-11-03

In long-distance, optical continuous-wave frequency transfer via fiber, remote bidirectional Er³ ⁺ -doped fiber amplifiers are commonly used to mitigate signal attenuation. We demonstrate for the first time the ultrastable transfer of an optical frequency using a remote fiber Brillouin amplifier, placed in a server room along the link. Using it as the only means of remote amplification, on a 660 km loop of installed underground fiber we bridge distances of 250 km and 160 km between amplifications. Over several days of uninterrupted measurement, we find an instability of the frequency transfer (Allan deviation of Λ-weighted data with 1 s gate time) of around 1 × 10(-19) and less for averaging times longer than 3000 s. The modified Allan deviation reaches 3 × 10(-19) at an averaging time of 100 s. Beyond 100 s it follows the interferometer noise floor, and for averaging times longer than 1000 s the modified Allan deviation is in the 10(-20) range. A conservative value of the overall accuracy is 1 × 10(-19)

Effect of laser frequency noise on fiber-optic frequency reference distribution

NASA Technical Reports Server (NTRS)

Logan, R. T., Jr.; Lutes, G. F.; Maleki, L.

1989-01-01

The effect of the linewidth of a single longitude-mode laser on the frequency stability of a frequency reference transmitted over a single-mode optical fiber is analyzed. The interaction of the random laser frequency deviations with the dispersion of the optical fiber is considered to determine theoretically the effect on the Allan deviation (square root of the Allan variance) of the transmitted frequency reference. It is shown that the magnitude of this effect may determine the limit of the ultimate stability possible for frequency reference transmission on optical fiber, but is not a serious limitation to present system performance.

DSS 13 frequency stability tests

NASA Technical Reports Server (NTRS)

Otoshi, T. Y.; Franco, M. M.

1987-01-01

In a previous article, the results of frequency stability tests at DSS 13 were presented in table form for tau = 1000 s for the test period May 1985 through March 1986. This article is a continuation of that initial report and presents specially selected Allan sigma (square root of variance) plots of each of the subsystem test previously reported. An additional result obtained from tests performed during July 1986 was included for completeness. The Allan sigma plots are useful in that frequency stability information is not only given for tau = 1000 s, but for tau values in the regions of 1, 100, 500, and 2000 s as well.

THE ROLE OF FARMERS IN MANAGING WATER Dr Tony Colman Professor Tony Allan Farmers manage about 92% of the water consumed by society which needs to recognise that farming practices and the decisions made by those who operate food supply chains - including corporates and those making public policy - determine how water is stewarded.

NASA Astrophysics Data System (ADS)

Colman, A. J.

2017-12-01

Title Food-water and society Dr. Tony Colman and Professor Tony Allan Abstract The purpose of the paper is to highlight some key relationships between water resources and society. First, water is an very important resource for society in that it provides an essential input to society's food supply chains. Secondly, it is an essential input to farmer livelihoods. About half of the families of the world still work in agriculture - albeit a declining proportion. Thirdly, farmers manage about 92% of the water consumed by society - including the blue water (surface and groundwater) for irrigation and the green water (effective rainfall) consumed on rainfed farms. They also account for about 66% of society's impacts on biodiversity and about 25% of emissions. Finally it will be argued that those who analyse allocation and management of water must recognise that farming practices and the decisions made by those who operate food supply chains - including corporates and those making public policy - must recognise that it is farmers and food consumers who determine how water is stewarded. It will be suggested that we need to understand that well informed consumers could be the regulators.

Edgar Allan Poe: The Army Years.

ERIC Educational Resources Information Center

Russell, J. Thomas

This issue of the United States Military Academy Library Bulletin reviews the reported facts of Poe's biography from his enlistment at the age of 15 to the termination of his military sojourn. The 1831 and the 1966 Corps of Cadets' subscriptions for Poe's "Poems" are also discussed, and a long-term inaccuracy regarding the poet's West…

Intensity stabilisation of optical pulse sequences for coherent control of laser-driven qubits

NASA Astrophysics Data System (ADS)

Thom, Joseph; Yuen, Ben; Wilpers, Guido; Riis, Erling; Sinclair, Alastair G.

2018-05-01

We demonstrate a system for intensity stabilisation of optical pulse sequences used in laser-driven quantum control of trapped ions. Intensity instability is minimised by active stabilisation of the power (over a dynamic range of > 104) and position of the focused beam at the ion. The fractional Allan deviations in power were found to be <2.2 × 10^{-4} for averaging times from 1 to 16,384 s. Over similar times, the absolute Allan deviation of the beam position is <0.1 μm for a 45 {μ }m beam diameter. Using these residual power and position instabilities, we estimate the associated contributions to infidelity in example qubit logic gates to be below 10^{-6} per gate.

University Students with Dyslexia: A Qualitative Exploratory Study of Learning Practices, Challenges and Strategies.

PubMed

MacCullagh, Lois; Bosanquet, Agnes; Badcock, Nicholas A

2017-02-01

People with dyslexia are vastly under-represented in universities (Katusic et al., , Richardson & Wydell, ; Stampoltzis & Polychronopoulou, ). This situation is of concern for modern societies that value social justice. This study was designed to explore learning experiences of university students with dyslexia and factors that could contribute to their success. Thirteen students with dyslexia and 20 non-dyslexic peers were interviewed about their university learning experiences using a semi-structured qualitative approach. Students with dyslexia described engaging in learning activities intensively, frequently and strategically. They reported challenges and strengths relating to study skills, lectures, assessments, technology and support services. They also described helpful strategies including self-directed adaptive techniques, provisions from lecturers and assistance from the university. These findings suggest that students with dyslexia experience broad challenges at university, but helpful strategies may be available. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

78 FR 47057 - Proposed Collection; Comment Request for Regulation Project

Federal Register 2010, 2011, 2012, 2013, 2014

2013-08-02

... final income, estate and gift, and employment tax regulations relating to elections made under the..., and purchase of services to provide information. Approved: July 29, 2013. Allan Hopkins, Tax Analyst...

An analytic technique for statistically modeling random atomic clock errors in estimation

NASA Technical Reports Server (NTRS)

Fell, P. J.

1981-01-01

Minimum variance estimation requires that the statistics of random observation errors be modeled properly. If measurements are derived through the use of atomic frequency standards, then one source of error affecting the observable is random fluctuation in frequency. This is the case, for example, with range and integrated Doppler measurements from satellites of the Global Positioning and baseline determination for geodynamic applications. An analytic method is presented which approximates the statistics of this random process. The procedure starts with a model of the Allan variance for a particular oscillator and develops the statistics of range and integrated Doppler measurements. A series of five first order Markov processes is used to approximate the power spectral density obtained from the Allan variance.

Relating the Hadamard Variance to MCS Kalman Filter Clock Estimation

NASA Technical Reports Server (NTRS)

Hutsell, Steven T.

1996-01-01

The Global Positioning System (GPS) Master Control Station (MCS) currently makes significant use of the Allan Variance. This two-sample variance equation has proven excellent as a handy, understandable tool, both for time domain analysis of GPS cesium frequency standards, and for fine tuning the MCS's state estimation of these atomic clocks. The Allan Variance does not explicitly converge for the nose types of alpha less than or equal to minus 3 and can be greatly affected by frequency drift. Because GPS rubidium frequency standards exhibit non-trivial aging and aging noise characteristics, the basic Allan Variance analysis must be augmented in order to (a) compensate for a dynamic frequency drift, and (b) characterize two additional noise types, specifically alpha = minus 3, and alpha = minus 4. As the GPS program progresses, we will utilize a larger percentage of rubidium frequency standards than ever before. Hence, GPS rubidium clock characterization will require more attention than ever before. The three sample variance, commonly referred to as a renormalized Hadamard Variance, is unaffected by linear frequency drift, converges for alpha is greater than minus 5, and thus has utility for modeling noise in GPS rubidium frequency standards. This paper demonstrates the potential of Hadamard Variance analysis in GPS operations, and presents an equation that relates the Hadamard Variance to the MCS's Kalman filter process noises.

Ten on Top from Down Under.

ERIC Educational Resources Information Center

Nist, Joan

1988-01-01

Discusses some works by the following Australian writers of young adult literature: Ivan Southall, Patricia Wrightson, Bill Scott, Ruth Manley, Allan Baillie, Colin Theile, Ruth Park, Lee Harding, Robin Klein, and Eleanor Spence. (MM)

For the relief of Allan Bolor Kelley.

THOMAS, 112th Congress

Rep. Waxman, Henry A. [D-CA-30

2011-02-17

Senate - 12/05/2012 Received in the Senate and Read twice and referred to the Committee on the Judiciary. (All Actions) Tracker: This bill has the status Passed HouseHere are the steps for Status of Legislation:

For the relief of Allan Bolar Kelley.

THOMAS, 111th Congress

Rep. Waxman, Henry A. [D-CA-30

2010-05-24

House - 06/03/2010 Referred to the Subcommittee on Immigration, Citizenship, Refugees, Border Security, and International Law. (All Actions) Tracker: This bill has the status IntroducedHere are the steps for Status of Legislation:

Genetics Home Reference: Allan-Herndon-Dudley syndrome

MedlinePlus

... Dudley syndrome and the monocarboxylate transporter 8 (MCT8) gene. Am J Hum Genet. 2005 Jul;77(1):41-53. Epub 2005 May 11. ... are genome editing and CRISPR-Cas9? What is precision medicine? What ...

The Doubling Moment: Resurrecting Edgar Allan Poe

ERIC Educational Resources Information Center

Minnick, J. Bradley; Mergil, Fernando

2008-01-01

This article expands upon Jeffrey Wilhelm's and Brian Edmiston's (1998) concept of a doubling of viewpoints by encouraging middle level students to use dramatization to take on multiple perspectives, to pose interpretive questions, and to enhance critical inquiry from inside and outside of texts. The doubling moment is both the activation of…

Optical-frequency transfer over a single-span 1840 km fiber link.

PubMed

Droste, S; Ozimek, F; Udem, Th; Predehl, K; Hänsch, T W; Schnatz, H; Grosche, G; Holzwarth, R

2013-09-13

To compare the increasing number of optical frequency standards, highly stable optical signals have to be transferred over continental distances. We demonstrate optical-frequency transfer over a 1840-km underground optical fiber link using a single-span stabilization. The low inherent noise introduced by the fiber allows us to reach short term instabilities expressed as the modified Allan deviation of 2×10(-15) for a gate time τ of 1 s reaching 4×10(-19) in just 100 s. We find no systematic offset between the sent and transferred frequencies within the statistical uncertainty of about 3×10(-19). The spectral noise distribution of our fiber link at low Fourier frequencies leads to a τ(-2) slope in the modified Allan deviation, which is also derived theoretically.

78 FR 24200 - Ocean Transportation Intermediary License Applicants

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-24

...: Hsiao-Ling Chen, President (QI), Application Type: QI Change Matus International, Inc. (NVO & OFF), 411 N. Oak Street, Inglewood, CA 90302, Officers: Anthony S. Pineda, Treasurer (QI), Allan J. Matus...] BILLING CODE 6730-01-P ...

How Should SOF Be Organized?

DTIC Science & Technology

2011-06-01

186 Eric Micheletti, French Special Forces: Special Operations Command (Paris: Histoire & Collections, 1999), 16. 187 NSCC, NATO SOF...University, September 2008. Micheletti, Eric. French Special Forces: Special Operations Command. Paris: Histoire & Collections, 1999. Millet, Allan

The Sublime and the Vulgar.

ERIC Educational Resources Information Center

Swann, Karen

1990-01-01

Explores how Edmund Burke's discourse on the sublime helps illuminate attacks on the vulgarization of culture (as typified by Allan Bloom), both for the presumedly "vulgar" reader and for the champions of high culture. (MG)

Study on phase noise induced by 1/f noise of the modulator drive circuit in high-sensitivity fiber optic gyroscope

NASA Astrophysics Data System (ADS)

Teng, Fei; Jin, Jing; Li, Yong; Zhang, Chunxi

2018-05-01

The contribution of modulator drive circuit noise as a 1/f noise source to the output noise of the high-sensitivity interferometric fiber optic gyroscope (IFOG) was studied here. A noise model of closed-loop IFOG was built. By applying the simulated 1/f noise sequence into the model, a gyroscope output data series was acquired, and the corresponding power spectrum density (PSD) and the Allan variance curve were calculated to analyze the noise characteristic. The PSD curve was in the spectral shape of 1/f, which verifies that the modulator drive circuit induced a low frequency 1/f phase noise into the gyroscope. The random walk coefficient (RWC), a standard metric to characterize the noise performance of the IFOG, was calculated according to the Allan variance curve. Using an operational amplifier with an input 1/f noise of 520 nV/√Hz at 1 Hz, the RWC induced by this 1/f noise was 2 × 10-4°/√h, which accounts for 63% of the total RWC. To verify the correctness of the noise model we proposed, a high-sensitivity gyroscope prototype was built and tested. The simulated Allan variance curve gave a good rendition of the prototype actual measured curve. The error percentage between the simulated RWC and the measured value was less than 13%. According to the model, a noise reduction method is proposed and the effectiveness is verified by the experiment.

Building and Operating Spacelab: Spacelab Design and Systems Engineering Panel

NASA Technical Reports Server (NTRS)

Roth, Axel; Berge, Klaus; Thirkettle, Alan; Craft, Harry G., Jr.; Benson, Robert

2000-01-01

This document is the transcription of the Spacelab Design and Systems Engineering Panel's discussion of the Spacelab program. It includes information on Spacelab's origin and development. The panel includes Klaus Berge, Bob Benson, Allan Thirkettle, and Harry Craft.

An algorithm for synchronizing a clock when the data are received over a network with an unstable delay

PubMed Central

Levine, Judah

2016-01-01

A method is presented for synchronizing the time of a clock to a remote time standard when the channel connecting the two has significant delay variation that can be described only statistically. The method compares the Allan deviation of the channel fluctuations to the free-running stability of the local clock, and computes the optimum interval between requests based on one of three selectable requirements: (1) choosing the highest possible accuracy, (2) choosing the best tradeoff of cost vs. accuracy, or (3) minimizing the number of requests to realize a specific accuracy. Once the interval between requests is chosen, the final step is to steer the local clock based on the received data. A typical adjustment algorithm, which supports both the statistical considerations based on the Allan deviation comparison and the timely detection of errors is included as an example. PMID:26529759

18. Photocopy of a photographca. 1950showing Lake Hodges Dam in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

18. Photocopy of a photograph--ca. 1950--showing Lake Hodges Dam in San Diego County, CA., during a period of low water. Courtesy Mr. Charles Allan Whitney. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

Chapter 7 : a quest for improved safety and security.

DOT National Transportation Integrated Search

2008-01-01

George H. W. Bush became President of the United States on : January 20, 1989. On February 6 Samuel Skinner became his first : secretary of transportation. FAA Administrator T. Allan McArtor : resigned on February 17, 1989, and Robert Whittington, ex...

Over 5,600 Japanese collection of Antarctic meteorites: Recoveries, curation and distribution

NASA Technical Reports Server (NTRS)

Yanai, K.; Kojima, H.

1986-01-01

The history of recovery of meteorite fragments in the Yamato Mountains, Allan Hills, and Victoria Land, Antarctica is reviewed. The Japanese collection of Antarctic meteorites were numbered, weighed, photographed, identified, and classified. Sample distribution of the Japanese Antarctic meteorites is described.

Rethinking Relativism.

ERIC Educational Resources Information Center

Nathan, George J.

1991-01-01

Discusses Allan Bloom's "The Closing of the American Mind," examining his critique of relativism, particularly cultural relativism. The paper states that the existence of cultural relativism is a cause and sign of significant fragmentation and separateness in modern society and the university. (SM)

77 FR 35475 - Internal Revenue Service

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-13

... contributions, consideration does not include de minimis goods or services. It also provides guidance on how..., maintenance, and purchase of services to provide information. Approved: June 6, 2012. Allan Hopkins, Tax... DEPARTMENT OF THE TREASURY Internal Revenue Service Proposed Collection; Comment Request for...

Selected Writings on Philosophy and Adult Education. Second Edition.

ERIC Educational Resources Information Center

Merriam, Sharan B., Ed.

This book contains 27 essays on the philosophical foundations of adult education: "Cultural Studies in Adult Education" (Sir Richard Livingstone); "The Conflict in Education" (Robert M. Hutchins); "The Student and the University" (Allan Bloom); "Experience and Education" (John Dewey); "For Those Who…

Class Counts: An Overview and Response to Mr. Cooper's Review

ERIC Educational Resources Information Center

Ornstein, Allan

2009-01-01

This article presents Allan Ornstein's response to highly respected scholar, Bruce Cooper's review of Ornstein's 2007 book, "Class Counts: Education, Inequality and the Shrinking Middle Class." Here Ornstein attempts to elaborate on a few points that he felt Cooper missed in his review.

Management Development. Symposium 15. [Concurrent Symposium Session at AHRD Annual Conference, 2000.

ERIC Educational Resources Information Center

2000

Three presentations are provided from Symposium 15, Management Development, of the Academy of Human Resource Development (HRD) 2000 Conference Proceedings. "Conceptualizing Global Leadership from Multiple Perspectives: An Analysis of Behavioral Ratings" (Allan H. Church) examines the underlying nature of global leadership behavior using…

Antarctic Meteorite Newsletter, volume 6, number 2

NASA Technical Reports Server (NTRS)

1983-01-01

Meteorites from the 1981 and 1982 Antarctic collection are listed showing classification, weight, degree of weathering, degree of fractionation, % Fa, and % Fs. Physical and petrigraphic characteristics are described for 23 samples from the Allan Hills, Thiel Mountains, the Pecora Escarpment, and the Elephant Moraine locations.

Finnish-American Academic and Professional Exchanges: Analyses and Reminiscences.

ERIC Educational Resources Information Center

Copeland, William, Ed.; And Others

The origins, evolution, and current state of Finnish-American academic and professional exchange are reviewed. Personal evaluations by Finnish scholars are provided as follows: "Scholarly Exchanges with Finland: The Benefits to the United States" (Allan A. Kuusisto); "Finnish-American Academic and Professional Exchanges, A…

Expressing Yourself Poe-etically

ERIC Educational Resources Information Center

Gillespie, Joanne S.

2011-01-01

Middle grades teachers should create meaningful learning activities involving stimulating literature and interesting composition prompts. This article describes a unit in which eighth graders read short stories by Edgar Allan Poe. Using multiple learning and teaching approaches, they expanded their vocabularies, responded artistically to "The…

The Closing of the "Bazaar of Cultures": Anthropology as Scapegoat.

ERIC Educational Resources Information Center

Klass, Morton

1990-01-01

Notes Allan Bloom's attack on anthropologists and the concept of cultural relativism. Rejects the idea that the study of other cultures leads to giving up one's own culture. Suggests that Bloom represents a nativistic revitalization movement which has found that anthropologists make excellent scapegoats. (EVL)

Allan Variance Calculation for Nonuniformly Spaced Input Data

DTIC Science & Technology

2015-01-01

τ (tau). First, the set of gyro values is partitioned into bins of duration τ. For example, if the sampling duration τ is 2 sec and there are 4,000...Variance Calculation For each value of τ, the conventional AV calculation partitions the gyro data sets into bins with approximately τ / Δt...value of Δt. Therefore, a new way must be found to partition the gyro data sets into bins. The basic concept behind the modified AV calculation is

Mineral Biomarkers in Martian Meteorite Allan Hills 84001?

NASA Technical Reports Server (NTRS)

Thomas-Keprta, K. L.; Bazylinski, D. A.; Wentworth, S. J.; McKay, D. S.; Golden, D. C.; Gibson, E. K., Jr.; Romanek, C. S.

1998-01-01

The occurrence of fine-grained magnetite in the Fe-rich rims surrounding carbonate globules in the martian meteorite ALH84001, originally described in , have been proposed as fossil remains of primitive martian organisms. Here we report observations on size and shape distributions of magnetites from ALH84001 and compare them to biogenic and inorganic magnetite crystals of terrestrial origin. While some magnetite morphology is not unequivocally diagnostic for its biogenicity, such as cubodial forms of magnetite, which are common in inorganically formed magnetites, other morphologies of magnetite (parallel-epiped or elongated prismatic and arrowhead forms) are more likely signatures of biogenic activity. Some ALH 84001 magnetite particles described below have unique morphology and length-to-width ratios that are indistinguishable from a variety of terrestrial biogenic magnetite and distinct from all known inorganic forms of magnetite.

Edgar Allan Poe's "Ligeia": an object-relational interpretation.

PubMed

Zlotnick-Woldenberg, C

1999-01-01

This paper argues that Poe's short story "Ligeia," in which the narrator experiences the death of his adored first wife (Ligeia), a second marriage to the despised Rowena, and ultimately the death of Rowena and the revivification of Ligeia, is not a supernatural tale, but rather a psychological one. According to this reading, the poisoning of Rowena and the revivification of Ligeia are hallucinated by the narrator in the course of an opium-induced psychotic break. The antecedents to this break are explored in light of object relations theory, with particular emphasis placed on the way in which the two women function as part objects. Ligeia represents the narrator's romantic and spiritual side and is associated with the good mother, while Rowena, who represents his more mundane and materialistic side, is associated with the rejecting mother. It is argued that the narrator, functioning primarily in the schizoid position and employing such defense mechanisms as splitting and projection--which already require a high degree of fantasy--is not an unlikely candidate for such a break.

Bloom on Literature and Rock Music: The Challenge Facing Higher Education.

ERIC Educational Resources Information Center

Olivier, B.

1997-01-01

Disputing Allan Bloom's ("Closing of the American Mind") conviction that the fading of literary culture and growing attachment to rock music signals the decline of American civilization, discussion examines how literature, rock music, film, and critical reflection can be used to engage students intellectually without relinquishing either…

Coping with Standards, Tests, and Accountability: Voices from the Classroom.

ERIC Educational Resources Information Center

Glatthorn, Allan A., Ed.; Fontana, Jean, Ed.

This book presents the views of teachers, teacher educators, and administrators who write about accountability, testing, and standards programs. The chapters are: (1) "From Policy to Practice: The Research" (Allan A. Glatthorn); (2) "New York's Test-Driven Standards" (Jean Fontana); (3) "Voices from a Native American…

Bloom's Idiosyncratic History of the University.

ERIC Educational Resources Information Center

Lawler, Peter Augustine

1989-01-01

Analyzes "The Idiosyncratic History of the University," a chapter in Allan Bloom's "The Closing of the American Mind". Focuses on Bloom's history of the university as explained through Socrates' philosophy. Concentrates on the role of philosophers in society past and present. Discusses the Enlightenment, Existentialism,…

Poe and Prolixity.

ERIC Educational Resources Information Center

Powers, John

1990-01-01

Describes a method of teaching Edgar Allan Poe's writings which uses writing as a tool to decipher the story and to teach a valuable lesson in creative writing and style, and which shows students how a text changes when it is either abridged or adapted. (SR)

Robert Weinberg: Scientist of the Year.

ERIC Educational Resources Information Center

Langone, John

1983-01-01

Highlights the background, career, and major accomplishments of Robert Allan Weinberg, professor of Biology at the Massachusetts Institute of Technology. His accomplishments and research interests focus on oncogenes, genes capable of causing cancer. The discovery of these genes has revealed the central mechanism of cancer. (Author/JN)

Comparison of Human and Latent Semantic Analysis (LSA) Judgements of Pairwise Document Similarities for a News Corpus

DTIC Science & Technology

2004-09-01

University. Miro Kraetzl critically assessed the manuscript before it was sent for review. References Allan, J., Callan, J., Croft, W.B., Ballesteros, L...Conference (TREC 6). NIST Special Publication 500-240. Baayen,R.H. (2001). Word Frequency Distributions. Kluwer Academic Publishers, P.O. Box 322 , 3300

The savory method can not green deserts or reverse climate change

USDA-ARS?s Scientific Manuscript database

Mr. Allan Savory addressed one of the major environmental challenges of our time – rapidly increasing atmospheric CO2 concentrations and climate warming - in a video presentation entitled, "How to green the world's deserts and reverse climate change" that was presented at the 2013 TED (Technology, E...

An Invaluable Resource for Supporting Transgender, Transsexual, and Gender-Nonconforming Students in School Communities: A Review of "Supporting Transgender and Transsexual Students in K-12 Schools"

ERIC Educational Resources Information Center

Martino, Wayne

2013-01-01

This essay provides a review of a resource guide written by Kristopher Wells, Gayle Roberts, and Carol Allan (2012) titled "Supporting Transgender and Transsexual Students in K-12 Schools: A Guide for Educators". The guide is an invaluable resource for educators in schools and teacher education programs.

High stability lasers for lidar and remote sensing

NASA Astrophysics Data System (ADS)

Heine, Frank; Lange, Robert; Seel, Stefan; Smutny, Berry

2017-11-01

Tesat-Spacecom is currently building a set flight models of frequency stabilized lasers for the ESA Missions AEOLUS and LTP. Lasers with low intensity noise in the kHz region and analogue tuning capabilities for frequency and output power are developed for the on board metrology of the LTP project, the precursor mission for LISA. This type of laser is internally stabilized by precise temperature control, approaching an ALLAN variance of 10-9 for 100 sec. It can be easily locked to external frequency references with <50kHz bandwidth. The Seed laser for the AEOLUS mission (wind LIDAR) is used as the master frequency reference and is stabilized internally by a optical cavity. It shows a 3* 10-11 Allan variance from time intervals 1 sec - 1000 sec. Furthermore it is step-tunable for calibration of the receiver instrument with a speed of GHz / sec by a digital command interface. Performance and environmental test results will be presented.

The Deep Space Network stability analyzer

NASA Technical Reports Server (NTRS)

Breidenthal, Julian C.; Greenhall, Charles A.; Hamell, Robert L.; Kuhnle, Paul F.

1995-01-01

A stability analyzer for testing NASA Deep Space Network installations during flight radio science experiments is described. The stability analyzer provides realtime measurements of signal properties of general experimental interest: power, phase, and amplitude spectra; Allan deviation; and time series of amplitude, phase shift, and differential phase shift. Input ports are provided for up to four 100 MHz frequency standards and eight baseband analog (greater than 100 kHz bandwidth) signals. Test results indicate the following upper bounds to noise floors when operating on 100 MHz signals: -145 dBc/Hz for phase noise spectrum further than 200 Hz from carrier, 2.5 x 10(exp -15) (tau =1 second) and 1.5 x 10(exp -17) (tau =1000 seconds) for Allan deviation, and 1 x 10(exp -4) degrees for 1-second averages of phase deviation. Four copies of the stability analyzer have been produced, plus one transportable unit for use at non-NASA observatories.

76 FR 46898 - Quarterly Publication of Individuals, Who Have Chosen To Expatriate, as Required by Section 6039G

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-03

... BERLIAND MIRNDA LOUISE BERNIER JOCELYNE BERTHOLD DOROTHY ISABELLE BESSMERT DANIEL BIASUCCI JOHN W BJERTNES... CHARLES MARIE CHARTRAND MARC LEO CHEN ELIZABETH CHEN IRENE CHEUNG FUNG Y CHEUNG NERISSA SUI MAN CHIEN... KRAETZ MELVIS MARIA KREPP KERSTI MAY KRIENKE BJORN KUSTER PHILIPPE ALLAN KWAN MEI L LAI CHRISTINA FOO...

75 FR 19676 - Qualification of Drivers; Exemption Renewals; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-15

... exemptions for Lee A. Burke, Barton C. Caldara, Allan Darley, Robin S. England, Charles D. Grady, Richard Hailey, Jr., Robert V. Hodges, George R. Knavel, John R. Knott III, Timothy S. Miller, Roger D. Mollak... commercial motor vehicle (CMV) drivers. FOR FURTHER INFORMATION CONTACT: Dr. Mary D. Gunnels, Director...

75 FR 8184 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-23

.... Burke, Barton C. Caldara, Allan Darley, Robin S. England, Charles D. Grady, Richard Hailey, Jr., Robert V. Hodges, George R. Knavel, John R. Knott, III, Timothy S. Miller, Roger D. Mollak, Edward D....regulations.gov . FOR FURTHER INFORMATION CONTACT: Dr. Mary D. Gunnels, Director, Medical Programs, (202) 366...

Considerations of the Social, Individual, and Embodied: A Response to Comments on "Schema Theory Revisited"

ERIC Educational Resources Information Center

McVee, Mary B.; Gavelek, James R.; Dunsmore, Kailonnie L.

2007-01-01

This article presents the authors' response and clarifications to the comments of Margaret E. Gredler and of Karen A. Krasny, Mark Sadoski, and Allan Paivio on their article "Schema Theory Revisited." The authors first respond to Gredler's criticism contending that they "transmogrified" Harre's (1984) "ignominiously named...Vygotsky space" in…

Identification and Targeting of Tyrosine Kinase Activity in Prostate Cancer Initiation, Progression, and Metastasis

DTIC Science & Technology

2013-12-01

University) "Effectors of the DNA damage and radiotherapy response in cancer" 9:20 pm - 9:30 pm Discussion TUESDAY 7:30 am - 8:30 am Breakfast 9:00...M. Morris , Hideki Onagi, Timothy M. Altamore, Allan B. Gamble, Christopher J. Easton Prohormone-substrate peptide sequence recognition by

A Door Is a Big Wooden Thing with a Knob: Getting a Handle on Metaphorical Interface Design.

ERIC Educational Resources Information Center

Bishop, M. J.; Cates, Ward Mitchell

This paper chronicles the evolution of a metaphorical graphical user interface (MGUI) at Lehigh University (Pennsylvania). From its inception, "The Funeral of Edgar" has been a guided exploration of Edgar Allan Poe's poem, "The Raven," aimed at modeling high school students' critical and analytical reading skills. This product…

Modes of Learning: Whitehead's Metaphysics and the Stages of Education

ERIC Educational Resources Information Center

Allan, George

2012-01-01

Educators are familiar with Alfred North Whitehead's three stages of education: romance, precision, and generalization. Philosophers are familiar with his metaphysical theories about the primacy of temporal processes. In "Modes of Learning," George Allan brings these two sides of Whitehead's thought together for the first time in a book…

77 FR 59454 - Proposed Collection; Comment Request for Notice 2009-26

Federal Register 2010, 2011, 2012, 2013, 2014

2012-09-27

... the new tax incentives for Build America Bonds under Sec. 54AA of the Internal Revenue Code (``Code... material in the administration of any internal revenue law. Generally, tax returns and tax return... provide information. Approved: September 21, 2012. Allan Hopkins, Tax Analyst. [FR Doc. 2012-23727 Filed 9...

Evaluation of Meterorite Amono Acid Analysis Data Using Multivariate Techniques

NASA Technical Reports Server (NTRS)

McDonald, G.; Storrie-Lombardi, M.; Nealson, K.

1999-01-01

The amino acid distributions in the Murchison carbonaceous chondrite, Mars meteorite ALH84001, and ice from the Allan Hills region of Antarctica are shown, using a multivariate technique known as Principal Component Analysis (PCA), to be statistically distinct from the average amino acid compostion of 101 terrestrial protein superfamilies.

Managing Colleges and Universities: Issues for Leadership.

ERIC Educational Resources Information Center

Hoffman, Allan M., Ed.; Summers, Randal W., Ed.

This collection of papers highlights topics relating to leadership in higher education. After a "Foreword" (Dean L. Hubbard) and "Introduction" (Allan M. Hoffman and Randal W. Summers), the 12 chapters are: (1) "Organizational Structure, Management, and Leadership for the Future" (Richard Alfred and Scott Rosevear); (2) "The Practitioner's…

The Power and Pitfalls of Education Incentives. Discussion Paper 2011-07

ERIC Educational Resources Information Center

Allan, Bradley M.; Fryer, Roland G., Jr.

2011-01-01

There is widespread agreement that America's school system is in desperate need of reform, but many educational interventions are ineffective, expensive, or difficult to implement. Recent incentive programs, however, demonstrate that well-designed rewards to students can improve achievement at relatively low costs. Fryer and Allan draw on…

Response Acquisition under Targeted Percentile Schedules: A continuing Quandary for Molar Models of Operant Behavior

DTIC Science & Technology

1993-07-01

dimensions topics such as timing (e.g., Gibbon & Allan, from interresponse-time duration (e.g.. Alle- 1984), numerositv (e.g., Gallistel , 1989), and...Behavior, 51, 145-162. Snapper, A. G., & Inglis, G. B. (1985). SKED-li soft- Gallistel , C. R. (1989). Animal cognition: The repre- ware system. Kalamazoo

Time to Revisit the Heterogeneous Telescope Network

NASA Astrophysics Data System (ADS)

Hessman, F. V.

The "Heterogeneous Telescope Network" (HTN) was founded in 2005 as a loose collaboration of people somehow associated with robotic telescopes and/or projects interested in the transient universe. Other than being a very interesting forum for the exchange of ideas, the only lasting contribution of the HTN was a proposed protocol for the operation of a loose e-market for the exchange of telescope time (Allan et al. 2006; White & Allan 2007). Since the last formal meeting in 2007, the HTN has gone into a "Dornröschenschlaf" (a better word than "hibernation") : the players and interest are there, but the public visibility and activity is not. Although the participants knew and know that global networking is the way of the future for many types of science, various things have kept the HTN from taking the idea and actually implementing it: work on simply getting one's own system to work (e.g. myself), career paths of major players (e.g. Allan), dealing with the complexity of ones' own network (TALONS, RoboNet, LCO), and - most importantly - no common science driver big enough to push the participants to try it in earnest. Things have changed, however: robotic telescopes have become easier to create and operate, private networks have matured, large-scale consortia have become more common, event reporting using VOEvent has become the global standard and has a well-defined infrastructure, and large-scale sources of new objects and events are operating or will soon be operating (OGLE, CSS, Pan-STARRs, GAIA). I will review the scientific and sociological prospects for re-invigorating the HTN idea and invite discussion.

Terrestrial Ages of Antarctic Meteorites- Update 1999

NASA Technical Reports Server (NTRS)

Nishiizumi, Kunihiko; Welten, K. C.; Caffee, Marc W.

1999-01-01

We are continuing our ongoing study of cosmogenic nuclides in Antarctic meteorites. In addition to the studies of exposure histories of meteorites, we study terrestrial ages and pairing of Antarctic meteorites and desert meteorites. Terrestrial ages of Antarctic meteorites provide information on meteorite accumulation mechanisms, mean weathering lifetimes, and influx rates. The determination of Cl-36(half-life=3.01 x 10(exp 5) y) terrestrial ages is one of our long-term on-going projects, however, in many instances neither Cl-36 or C-14 (5,730 y) yields an accurate terrestrial age. Using Ca-14 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the c,ap in half-life between 14-C and Cl-36 ages. We are now applying the new Ca-41- Cl-36 terrestrial age method as well as the Cl-36-Be-10 method to Antarctic meteorites. Our measurements and C-14 terrestrial age determinations by the University of Arizona group are always complementary. We have measured Cl-36 in over 270 Antarctic meteorites since our previous compilation of terrestrial ages. Since a large number of meteorites have been recovered from many different icefields in Antarctica, we continue to survey the trends of terrestrial ages for different icefields. We have also measured detailed terrestrial ages vs. sample locations for Allan Hills, Elephant Moraine, and Lewis Cliff Icefields, where meteorites have been found with very long ages. The updated histograms of terrestrial ages of meteorites from the Allan Hills Main Icefield and Lewis Cliff Icefield are shown. These figures include C-14 ages obtained by the University of Arizona group. Pairs of meteorites are shown as one object for which the age is the average of all members of the same fall. The width of the bars represents 70,000 years, which was a typical uncertainty for Cl-36 ages. We reduced the uncertainty of terrestrial age determinations to approx. 40,000 years by using pairs of nuclides such as Ca-41-Cl-36 or Cl

High-resolution continuous flow analysis setup for water isotopic measurement from ice cores using laser spectroscopy

NASA Astrophysics Data System (ADS)

Emanuelsson, B. D.; Baisden, W. T.; Bertler, N. A. N.; Keller, E. D.; Gkinis, V.

2014-12-01

Here we present an experimental setup for water stable isotopes (δ18O and δD) continuous flow measurements. It is the first continuous flow laser spectroscopy system that is using Off-Axis Integrated Cavity Output Spectroscopy (OA-ICOS; analyzer manufactured by Los Gatos Research - LGR) in combination with an evaporation unit to continuously analyze sample from an ice core. A Water Vapor Isotopic Standard Source (WVISS) calibration unit, manufactured by LGR, was modified to: (1) increase the temporal resolution by reducing the response time (2) enable measurements on several water standards, and (3) to reduce the influence from memory effects. While this setup was designed for the Continuous Flow Analysis (CFA) of ice cores, it can also continuously analyze other liquid or vapor sources. The modified setup provides a shorter response time (~54 and 18 s for 2013 and 2014 setup, respectively) compared to the original WVISS unit (~62 s), which is an improvement in measurement resolution. Another improvement compared to the original WVISS is that the modified setup has a reduced memory effect. Stability tests comparing the modified WVISS and WVISS setups were performed and Allan deviations (σAllan) were calculated to determine precision at different averaging times. For the 2013 modified setup the precision after integration times of 103 s are 0.060 and 0.070‰ for δ18O and δD, respectively. For the WVISS setup the corresponding σAllan values are 0.030, 0.060 and 0.043‰ for δ18O, δD and δ17O, respectively. For the WVISS setup the precision is 0.035, 0.070 and 0.042‰ after 103 s for δ18O, δD and δ17O, respectively. Both the modified setups and WVISS setup are influenced by instrumental drift with δ18O being more drift sensitive than δD. The σAllan values for δ18O of 0.30 and 0.18‰ for the modified (2013) and WVISS setup, respectively after averaging times of 104 s (2.78 h). The Isotopic Water Analyzer (IWA)-modified WVISS setup used during the

May 2012 DMM Podcast: an interview with Mark Fishman

PubMed Central

2012-01-01

SUMMARY Mark Fishman, President of the Novartis Institutes for BioMedical Research, discusses developing the zebrafish as a research tool, academia-industry collaborations and perspectives on the future of drug development. Narrated by Sarah E. Allan. To listen to this podcast, visit http://www.biologists.com/DMM/podcasts/index.html.

14. Photocopy of a photographca. 1902taken by A.W. Peters showing ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

14. Photocopy of a photograph--ca. 1902--taken by A.W. Peters showing Eastwood and his party surveying for the Big Creek Project. The surveying party is visible in the upper right corner. Courtesy Mr. Charles Allan Whitney. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

Red Dirt Thinking on Child Wellbeing in Indigenous, Rural and Remote Australian Communities: The SpICE Model "I Just Don't Want my Kid to Struggle Like I Did at School"

ERIC Educational Resources Information Center

Clarke, Kendall; Denton, Marijke

2013-01-01

Supporting children in their early development and learning has long-term benefits for both them and the broader community. Yet in Australia we still have significant examples of inequality of opportunity (Allan, 2010) and other structural barriers to family wellbeing, particularly in Indigenous and rural and remote communities (Bourke, Humphreys,…

78 FR 27281 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-09

... Federal Motor Carrier Safety Regulations. They are unable to meet the vision requirement in one eye for...) in interstate commerce without meeting the prescribed vision requirement in one eye. If granted, the.... Qualifications of Applicants Allan L. Anthony Mr. Anthony, age 54, has had refractive amblyopia in his left eye...

"Why Will You Say That I Am Mad?" Using Poe's "Tell-Tale Heart" as a Composition Model.

ERIC Educational Resources Information Center

Bates, Laura Raidonis

1998-01-01

Describes an exercise for basic writers which encompasses reading, listening, and writing. Finds that Edgar Allan Poe's "Tell-Tale Heart" has an effective vocabulary, a first-person conversational tone for the "mad" voice, and a second-person direct address that makes it easy to follow. Notes that inexperienced readers can…

Erotic Pedagogy's Noble Lie.

ERIC Educational Resources Information Center

Goicoechea, David L.

1991-01-01

According to author Allan Bloom, problems in today's university stem from lack of belief in the university's vocation. The paper evaluates his Socratic solution which states the country must recover a belief in and response to the university's primary calling (the promotion of discussion and speculation in a Socratic manner). (SM)

Equitable Research: A Bridge Too Far?

ERIC Educational Resources Information Center

Walls, Leon

2017-01-01

This paper is written in response to Angela Chapman and Allan Feldman's research study, "Cultivation of science identity through authentic science in an urban high school [classroom]". I utilize this forum piece to extend the call for "awakening a dialogue" that critically assesses the effectiveness of current K-12 science…

America's Opinion Leader Historians on Behalf of Success.

ERIC Educational Resources Information Center

Carpenter, Ronald H.

1983-01-01

Examines the rhetorical role of several twentieth century historians who were opinion leaders on behalf of the American way of achieving success: by emulating the earlier qualities of our frontier and founding fathers. Discusses the role of Frederick Turner Jackson, Charles A. Beard, Carl Becker, Allan Nevins, and others. (PD)

African American Art from the Collection of the Wadsworth Atheneum. The Martin Office of Museum Education.

ERIC Educational Resources Information Center

Chapman, Luisa Washington

This slide kit presents the diverse stylistic achievements of 15 African-American artists who worked between mid-19th century to present day. Essays included in the packet incorporate information from interviews with artists Hughie Lee-Smith, Elizabeth Catlett, Benny Andrews, Lois Mailou Jones, Allan Rohan Crite, Howardena Pindell, and Jack…

Dueler’s Dilemma: A One-Person Computer Gaming Platform for Decision Making

DTIC Science & Technology

2007-11-01

Peter Tikuisis; Keefe, Allan A.; DRDC Toronto TM 2007-091; R & D pour la défense Canada – Toronto; Novembre 2007. « Dueler’s Dilemma » est un jeu... 13 5 Summary...numbers. The possibility that both the subject and opponent are hit is negligible and therefore ignored (see text). .................................. 13

Reclaiming the Power of Subversive Language in Romantic and Transcendental Literature

ERIC Educational Resources Information Center

Nugent, Kelly Ann

2004-01-01

A high school teacher tries to eliminate the obstacles to subversive teaching in public schools by asking them to design schools that embodied the principles of learning suggested by the romantic and transcendental writers like Emily Dickinson, Ralph Waldo Emerson, Edgar Allan Poe, Henry David Thoreau, and Walt Whitman. It helps the students…

What's Happening in January?

ERIC Educational Resources Information Center

Toro, Leonor

The booklet contains brief information on nine January events celebrated by Puerto Ricans: New Year; Epiphany; and the birthdays of Betsy Ross, Eugenio Maria de Hostos, Dr. Martin Luther King, Benjamin Franklin, Edgar Allan Poe, William McKinley, and Franklin Delano Roosevelt. Designed as a teacher resource, the booklet includes brief biographical…

34th Annual Gun and Ammunitions Symposium and Exhibition held in Monterey, CA on 26-29 April 1999

DTIC Science & Technology

1999-04-01

Allan Buckley, Oerlikon Contraves ൫/50MM HETF (High Explosive Time Fuze) Ammunition" by Mr. Stephen Kerk and Mr. Peter Moore,* Diehl Stifung & Co...Technologies, Inc. "OICW Fire Control System" by Mr. Grant Moule*; Ms. Susan Franciscus*, Contraves Brashear Systems L.P. "Air Bursting Systems" by Mr. John

The National Guard in War: An Historical Analysis of the 27th Infantry Division (New York National Guard) in World War 2

DTIC Science & Technology

1990-06-01

1935. McNair, Leslie J., memorandun dated 12 July 1944, subject: "Recommendations on the Post-War National GuLard". Millet , Allan R., Semper...Moenk, Jean R., A History of Large Scale Maneuvers in the US. 1933-1964, (Ft Monroe, VA: HQ, CONARC, 1969). Moskin, J. Robert, The US Marine Corps

Organizational Culture and Climate. Symposium 24. [Concurrent Symposium Session at AHRD Annual Conference, 2000.

ERIC Educational Resources Information Center

2000

This document contains three papers from a symposium on organizational culture and climate that was conducted as part of a conference on human resource development (HRD). "A Comparative Profile of Workgroup Climate in Different Organizational Settings" (Allan H. Church) reports on a comparative analysis of climate data on more than 5,000…

Teaching Religious Doubt with Toulmin's Model of Reasoning

ERIC Educational Resources Information Center

Horne, Milton P.

2008-01-01

Teaching students to doubt, that is, to "test," theological arguments as one might test any other kind of knowledge is challenging in that the warrant for such testing is not immediately clear. Stephen Toulmin, Richard Rieke, and Allan Janik's model of reasoning provides a conceptual framework that demonstrates the logical relationships between a…

Reexamining the Structure of Hemingway's "The Doctor and the Doctor's Wife."

ERIC Educational Resources Information Center

Mulvey, James

2003-01-01

Considers how Hemingway's "The Doctor and the Doctor's Wife" is a model of Edgar Allan Poe's aesthetic of the short story. Examines this work on many levels. Concludes that great writers, such as Ernest Hemingway, challenge readers to find the clues, to connect the dots, to pay attention to the "little details." (SG)

Utilizing the Six Realms of Meaning in Improving Campus Standardized Test Scores through Team Teaching and Strategic Planning

ERIC Educational Resources Information Center

Stevenson, Rosnisha D.; Kritsonis, William Allan

2009-01-01

This article will seek to utilize Dr. William Allan Kritsonis' book "Ways of Knowing Through the Realms of Meaning" (2007) as a framework to improve a campus's standardized test scores, more specifically, their TAKS (Texas Assessment of Knowledge and Skills) scores. Many campuses have an improvement plan, also known as a Campus…

Ancient, Renaissance, and Modern: The Human in the Humanities.

ERIC Educational Resources Information Center

Kallendorf, Craig

1987-01-01

Highlights major points concerning the scope and purpose of the humanities from five educational treatises from the Italian Renaissance. Compares them with Allan Bloom's and E. D. Hirsch, Jr.'s, ideas and revisionist approaches to literature studies. Concludes that the right and left perceive the humanities as a means to political power. (DMM)

Fetal Alcohol Exposure Reduces Adult Brain Plasticity. Science Briefs

ERIC Educational Resources Information Center

National Scientific Council on the Developing Child, 2007

2007-01-01

"Science Briefs" summarize the findings and implications of a recent study in basic science or clinical research. This Brief summarizes the findings and implications of "Moderate Fetal Alcohol Exposure Impairs the Neurogenic Response to an Enriched Environment in Adult Mice" (I. Y. Choi; A. M. Allan; and L. A. Cunningham). Observations of mice…

The Psychophysics of Contingency Assessment

ERIC Educational Resources Information Center

Allan, Lorraine G.; Hannah, Samuel D.; Crump, Matthew J. C.; Siegel, Shepard

2008-01-01

The authors previously described a procedure that permits rapid, multiple within-participant evaluations of contingency assessment (the "streamed-trial" procedure, M. J. C. Crump, S. D. Hannah, L. G. Allan, & L. K. Hord, 2007). In the present experiments, they used the streamed-trial procedure, combined with the method of constant stimuli and a…

Looking for a correlation between terrestrial age and noble gas record of H chondrites

NASA Astrophysics Data System (ADS)

Loeken, Th.; Schultz, L.

1994-07-01

On the basis of statistically significant concentration differences of some trace elements, it has been suggested that H chondrites found in Antarctica and Modern Falls represent members of different extraterrestrial populations with different thermal histories. It was also concluded that H chondrites found in Victoria Land (Allan Hills) differ chemically from those found in Queen Maud Land (Yamato Mountains), an effect that could be based on the different terrestrial age distribution of both groups. This would imply a change of the meteoroid flux hitting the Earth on a timescale that is comparable to typical terrestrial ages of Antarctic chondrites. A comparison of the noble gas record of H chondrites from the Allan Hills icefields and Modern Fall shows that the distributions of cosmic-ray exposure ages and the concentrations of radiogenic He-4 and Ar-40 are very similar. In an earlier paper we compared the noble gas measurements of 20 Yamato H contents with meteorites from the Allan Hills region and Modern Falls. Similar distributions were found. The distribution of cosmic-ray exposure ages and radiogenic He-4 and Ar-40 gas contents as a function of the terrestrial age is investigated in these chondrites. The distribution shows the well-known 7-Ma-cluster indicating that about 40% of the H chondrites were excavated from their parent body in a single event. Both populations, Antarctic Meteorites and Modern Falls, exhibit the same characteristic feature: a major meteoroid-producing event about 7 Ma. This indicates that one H-group population delivers H chondrites to Antarctica and the rest of the world. Cosmic-ray exposure ages and thermal-history indicaters like radiogenic noble gases show no evidence of a change in the H chondrite meteoroid population during the last 200,000 years.

Alan Bloom's "The Closing of the American Mind": Two Perspectives.

ERIC Educational Resources Information Center

Greene, Maxine; Birenbaum, William

This colloquium report contains two papers that present perspectives on the book, "The Closing of the American Mind," by Allan Bloom. The first paper, by Maxine Greene, covers the book's philosophy. It asserts that the book deals with issues of American literacy on a superficial level, and actually is more concerned with refuting points…

The 1984-1985 Antarctic Search for Meteorites (ANSMET) Field Program

NASA Technical Reports Server (NTRS)

Sandford, Scott A.

1986-01-01

The purpose of the 1984-1985 ANSMET (Antarctic Search for Meteorites) expedition was to recover meteorites from the Main, Near Western, Middle Western, and Far Western icefields in the Allan Hills area and to carry out a reconnaissance of other nearby blue icefields. A brief summary of the locations and maps visited are provided.

Elevated Serum Triiodothyronine and Intellectual and Motor Disability with Paroxysmal Dyskinesia Caused by a Monocarboxylate Transporter 8 Gene Mutation

ERIC Educational Resources Information Center

Fuchs, Oliver; Pfarr, Nicole; Pohlenz, Joachim; Schmidt, Heinrich

2009-01-01

"Monocarboxylate transporter 8" ("MCT8" or SLC16A2) is important for the neuronal uptake of triiodothyronine (T3) in its function as a specific and active transporter of thyroid hormones across the cell membrane, thus being essential for human brain development. We report on a German male with Allan-Herndon-Dudley syndrome…

Sociocultural Influences on Science and on Science Identities

ERIC Educational Resources Information Center

Guerra, Andreia; Rezende, Flavia

2017-01-01

Angela Chapman and Allan Feldman (2016) conducted a study that aimed to exam how a group of diverse urban high school students were affected by the participation in a contextually based authentic science experience. The analysis of all data led the authors to conclude that the experience of authentic science positively influenced the science…

TESL Reporter, Vol. 4, No. 3.

ERIC Educational Resources Information Center

Pack, Alice C., Ed.

This issue contains the following articles: "A Portfolio Program for Teaching English Composition," by Charles J. Fox and Robert Tippetts: "TESL Curriculum: The Foundation Is What Counts," by William D. Conway: "English Oral Language," by Allan D. Patterson: "Using a Telephone Directory to Teach English as a Second Language," by Jason B. Alter;…

The Artist of the Beautiful: An Allegory for Our Times

ERIC Educational Resources Information Center

Thornton, Kathleen

2005-01-01

Following her return to the classroom after a two-year administrative absence, Kathleen Thornton--the Director of Undergraduate English Advisement and a lecturer at the University of Albany, New York--was struck by the language her undergraduate students used to discuss the stories of authors such as Edgar Allan Poe or Nathaniel Hawthorne. While…

White Matter Abnormalities and Dystonic Motor Disorder Associated with Mutations in the "SLC16A2" Gene

ERIC Educational Resources Information Center

Gika, Artemis D.; Siddiqui, Ata; Hulse, Anthony J.; Edward, Selvakumari; Fallon, Penny; McEntagart, Meriel E.; Jan, Wajanat; Josifova, Dragana; Lerman-Sagie, Tally; Drummond, James; Thompson, Edward; Refetoff, Samuel; Bonnemann, Carsten G.; Jungbluth, Heinz

2010-01-01

Aim: Mutations in the "SLC16A2" gene have been implicated in Allan-Herndon-Dudley syndrome (AHDS), an X-linked learning disability syndrome associated with thyroid function test (TFT) abnormalities. Delayed myelination is a non-specific finding in individuals with learning disability whose genetic basis is often uncertain. The aim of this study…

Four Takes on Tough Times

ERIC Educational Resources Information Center

Rebell, Michael A.; Odden, Allan; Rolle, Anthony; Guthrie, James W.

2012-01-01

Educational Leadership talks with four experts in the fields of education policy and finance about how schools can weather the current financial crisis. Michael A. Rebell focuses on the recession and students' rights; Allan Odden suggests five steps schools can take to improve in tough times; Anthony Rolle describes the tension between equity and…

National Agenda: A Holistic Approach towards Development of the Campus Improvement Plan Using "Ways of Knowing through the Realms of Meaning" as the Framework

ERIC Educational Resources Information Center

Cloud, Michelle; Kritsonis, William Allan

2006-01-01

This article seeks to examine "Ways of Knowing Through the Realms of Meaning" (2007) by Dr. William Allan Kritsonis as a framework that transformational educational leaders can use to guide members of the Site Based Decision Making Team through development of the Campus Improvement Plan. The Campus Improvement Plan serves as a blueprint for…

National Agenda: Development of Best Practices in Human Resources Using "Ways of Knowing through the Realms of Meaning" as the Framework

ERIC Educational Resources Information Center

Cloud, Michelle; Kritsonis, William Allan

2007-01-01

The purpose of this article is to examine "Ways of Knowing through the Realms of Meaning" by Dr. William Allan Kritsonis as a framework that innovative and progressive leaders in education can use to implement and utilize the absolute best practices regarding Human Resources in an educational organization. Dr Kritsonis's "Ways of Knowing through…

Total Quality Management: Implications for Higher Education.

ERIC Educational Resources Information Center

Hoffman, Allan M., Ed.; Julius, Daniel J., Ed.

This book contains 19 papers describing the implementation of Total Quality Management in a variety of higher education settings. Following a Foreword by Peter Likins and a Preface by Daniel J. Julius, the chapter titles and authors are: (1) "TQM: Implications for Higher Education--A Look Back to the Future" (Allan M. Hoffman and Randall…

Who Are Equals?

ERIC Educational Resources Information Center

Cohen, Carl

1978-01-01

The problem of affirmative action in college admission policies is addressed in view of the case of The Regents of the University of California v. Allan Bakke. It is noted that the essence of the case is preference by race and that official favoritism by race or national origin is poison to American society. (LBH)

What's Worth Teaching? Rethinking Curriculum in the Age of Technology. Technology, Education--Connections (The TEC Series)

ERIC Educational Resources Information Center

Collins, Allan

2017-01-01

This important contribution to the future of education, by bestselling author and renowned cognitive scientist Allan Collins, proposes a school curriculum that will fit the needs of our modern era. Offering guidelines for deciding what is important to learn in order to become a knowledgeable person, a good citizen, a thoughtful worker, and a…

a Theoretical and Experimental Investigation of 1/F Noise in the Alpha Decay Rates of AMERICIUM-241.

NASA Astrophysics Data System (ADS)

Pepper, Gary T.

New experimental methods and data analysis techniques were used to investigate the hypothesis of the existence of 1/f noise in a alpha particle emission rates for ^{241}Am. Experimental estimates of the flicker floor were found to be almost two orders of magnitude less than Handel's theoretical prediction and previous measurements. The existence of a flicker floor for ^{57}Co decay, a process for which no charged particles are emitted, indicate that instrumental instability is likely responsible for the values of the flicker floor obtained. The experimental results and the theoretical arguments presented indicate that a re-examination of Handel's theory of 1/f noise is appropriate. Methods of numerical simulation of noise processes with a 1/f^{rm n} power spectral density were developed. These were used to investigate various statistical aspects of 1/f ^{rm n} noise. The probability density function for the Allan variance was investigated in order to establish confidence limits for the observations made. The effect of using grouped (correlated) data, for evaluating the Allan variance, was also investigated.

Allan Cormack, Computerized Axial Tomography (CAT), and Magnetic Resonance

Science.gov Websites

Radiopharmaceuticals, DOE Technical Report, 1977 Emission Computed Tomography: A New Technique for the Quantitative Extending the Power of Nuclear Magnetic Resonance Techniques Magnetic Resonance Imaging Research Top Some

Rubidium-Strontium Formation Age of Allan Hills 84001 Carbonates

NASA Technical Reports Server (NTRS)

Borg, L. E.; Nyquist, L. E.; Shih, C.-Y.; Weismann, H.; Reese, Y.; Connelly, J. N.

1998-01-01

Our preferred age for the formation of carbonates in the martian meteorite ALH 84001 is 3.90 plus or minus 0.04 Ga for Lambda (Rubidium 87) equals 0.01402 Ga (exp -1), or 3.85 plus or minus 0.04 Ga for Lambda (Rubidium 87) = 0.0142 Ga(exponent -1). This age is determined by a three-point Rb-Sr isochron defined by leachates of high-graded carbonate-rich material. Major cation and especially phosphorous analyses of the leachates permit contributions from igneous whitlockite to be recognized for low-acidity leachates, and the corresponding data are omitted from the isochron. Data for the two highest acidity leachates plot close to the preferred isochron, but are omitted because we believe they contain contributions leached from the pyroxene substrate on which most of the carbonates are found. Nevertheless, the isochron age for all five highest-acidity leachates is 3.94 plus or minus 0.04 Ga, and is within error of the age obtained for the more restricted data set. All leachates used to define the isochron have major cation compositions that are singular to those obtained by microprobe analyses of the carbonate rosettes and are consistent with progressive digestion of the carbonates according to their composition. The age thus obtained for the carbonates is about 600 m.y. younger than the crystalization age of ALH 84001 determined by Sm-Nd analyses but is within error limits of the age of impact metamorphism inferred from the Rb-Sr and Ar-Ar systematics of silicates. which yield ages of 3.85 plus or minus 0.05 Ga and 4.05- 3.80 Ga to 4.3-3.8 Ga, respectively. Similarities between the carbonate crystallization age and the age of impact metamorphism as determined by Ar-Ar and Rb-Sr suggest that the carbonate formation is impact-related. Nevertheless, both high and low- temperature scenarios for the origin of the carbonates are possible.

Improving Student Learning When Budgets Are Tight

ERIC Educational Resources Information Center

Odden, Allan R.

2012-01-01

How do you stay focused on increasing student learning when budget cuts threaten everything you are striving for? This book offers a comprehensive framework to enhance student achievement in good times and in bad. School reform expert Allan R. Odden outlines a school improvement action plan focused sharply on student learning and then shows how to…

Body and Soul: The Musical Miseducation of Youth.

ERIC Educational Resources Information Center

Bayles, Martha

1998-01-01

Considers Allan Bloom's criticism of popular music in "The Closing of the American Mind." An examination of the music popular with young people, including a look at Afro-American music, suggests that it has virtues that will survive and that love for contemporary music is not the moral and cultural dead end Bloom has suggested. (SLD)

The Black Press and the Bakke Case: An Analysis of Coverage.

ERIC Educational Resources Information Center

Poindexter, Paula M.; Stroman, Carolyn A.

The content of four black newspapers was analyzed to determine how they covered the "Regents of the University of California v. Bakke" case, in which the Supreme Court ruled against rigid race quota programs such as the one that had prevented Allan Bakke, a white man, from being admitted to medical school. Each issue of the four…

77 FR 7233 - Qualification of Drivers; Exemption Applications; Vision

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-10

.... Knavel (UT) John R. Knott, III (MD) Timothy S. Miller (AZ) Edward D. Pickle (GA) Ezequiel M. Ramirez (TX...: Background Under 49 U.S.C. 31136(e) and 31315, FMCSA may renew an exemption from the vision requirements in... exemption for a renewable two-year period. They are: Lee A. Burke (WI) Barton C. Caldara (WI) Allan Darley...

Agonizing Poe

ERIC Educational Resources Information Center

Kiskis, Michael J.

2006-01-01

This article discusses the author's experience of teaching Edgar Allan Poe as part of the American literature survey at Elmira College in Elmira, New York. While his specialty is Mark Twain, his students would be much happier if they could skip the colonial and national period, and move directly to studying Poe. In this article, the author…

Interview with Jessica Utts

ERIC Educational Resources Information Center

Rossman, Allan; Utts, Jessica

2014-01-01

This article offers a transcript of author Allan Rossman's interview with Jessica Utts, Professor and Chair of Statistics at the University of California-Irvine. Utts is also a Fellow of the American Statistical Association and a recipient of a Founders Award from ASA. Additionally, she has been elected as President of ASA for the year 2016. The…

Drake appointed

NASA Astrophysics Data System (ADS)

AGU Past President Charles L. Drake has been appointed to the new President's Council of Advisors on Science and Technology. The 13-member council, named February 2, is chaired by D. Allan Bromley, science advisor to President George Bush, and reports directly to the president. The last presidental science council served President Richard Nixon, who disbanded it in 1972.

Learning From Loneliness.

ERIC Educational Resources Information Center

Geller, Robert

1967-01-01

Allan Sillitoe's "The Loneliness of the Long Distance Runner" and the movie version of that novel capture the imagination of students because of the stature of the hero, Colin Smith. He refuses to "play it cool" or to "cop out"; he loses his race and wins his manhood. To the students, he carries the command to hold on…

Debating the Role of Tocqueville in Inclusive Education: Making the Distinction between an Academic and a Political Education

ERIC Educational Resources Information Center

Connolley, Steven; Hausstatter, Rune Sarromaa

2009-01-01

This article presents the authors' response to the commentaries on their article. In reply to Julie Allan they contend that it is not so much the exposure to democratic ideas that they are against as much as the argument that democratic practices ought to be a central element in schooling. Moreover, they do not argue that introducing democratic…

DOE Research and Development Accomplishments Nobels in Medicine Associated

Science.gov Websites

Wells Beadle 1958 Physiology or Medicine Sir Peter Mansfield Physiology or Medicine C 1997 Allan M . Cormack 1979 Physiology or Medicine Stanley Prusiner Physiology or Medicine M 1983 Sir Peter Mansfield 2003 Physiology or Medicine Barbara McClintock Physiology or Medicine Barbara McClintock 1983

Writing a Core Curriculum: Classic Books and Student Compositions.

ERIC Educational Resources Information Center

Chapman, David W.

Recent years have witnessed a great upsurge in interest in a core curriculum. However, there has been some disagreement as to what should be included or how it should be defined. Allan Bloom has argued most strongly that the "Great Books" should form the basis of the core curriculum. Not only is the term itself ambiguous, but the…

National Implications: Implementing Postmodernistic Strategies and the "Ways of Knowing through the Realms of Meaning" for the Improvement of Ethical Conduct for the Improvement of Public Education

ERIC Educational Resources Information Center

Cloud, Michelle; Kritsonis, William Allan

2008-01-01

The intent of this article is to illustrate the effectiveness of using the tenets described in the "Ways of Knowing Through the Realms of Meaning" by Dr. William Allan Kritsonis (2007) to improve ethical conduct. Ten recommendations to implement the "Ways of Knowing Through the Realms of Meaning" (2007) for the improvement of ethical conduct are…

National Implications: Implementing the "Ways of Knowing through the Realms of Meaning" for the Improvement of Ethical Conduct

ERIC Educational Resources Information Center

Cloud, Michelle; Kritsonis, William Allan

2007-01-01

The intent of this article is to illustrate the effectiveness of using the tenets described in the Ways of Knowing Through the Realms of Meaning by Dr. William Allan Kritsonis (2007) to improve ethical conduct. Ten recommendations to implement the Ways of Knowing Through the Realms of Meaning for the improvement of ethical conduct are provided.…

77 FR 64187 - Proposed Collection; Comment Request for Form 637 Questionnaires

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-18

... 637 Questionnaires AGENCY: Internal Revenue Service (IRS), Treasury. ACTION: Notice and request for... Questionnaires A, B, C, D, E, F, H, I, J, K, M, Q, R, S, T, UP, UV, V, W, X, and Y, Form 637 Questionnaires... information or copies of Form 637 Questionnaires should be directed to Allan Hopkins, (202)-622-6665, at...

Bakke's Case vs. the Case for Affirmative Action

ERIC Educational Resources Information Center

Smith, Ralph R.

1978-01-01

Before the Supreme Court is Allan Bakke's claim that he was denied medical school admission because 16 reserved places were granted to minority applicants. Professor Smith believes the case is weak, that admissions are best left to university discretion, and that whatever the Court renders, the questions raised by Bakke will not be put to rest.…

The Intergenerational Transmission of Inspiration: Reflections on the Origin of a Peer-Mentoring Project

ERIC Educational Resources Information Center

Ward, Elijah G.

2012-01-01

The author gives a personal account of his relationship with his graduate mentor, Allan Schnaiberg. He also describes a mentoring project that he created with a colleague. The mentoring project emerges as both a vehicle for and a window onto the intergenerational transmission of the mentoring disposition of Schnaiberg. It stands as but one of many…

36 CFR 294.29 - List of designated Idaho Roadless Areas.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Perce Rapid River 922 X X Nez Perce Salmon Face 855 X Nez Perce Selway Bitterroot X Nez Perce Silver... Payette Snowbank 924 X Payette Sugar Mountain 014 X Salmon Agency Creek 512 X X Salmon Allan Mountain 946 X X Salmon Anderson Mountain 942 X Salmon Blue Joint Mountain 941 X Salmon Camas Creek 901 X Salmon...

The Importance of Forgetting "Perishing" in Whitehead's Cosmology and Epistemology

ERIC Educational Resources Information Center

Flynn, Mark

2005-01-01

In this paper, I will address a constructive criticism of the papers that appeared as a Symposium on Whitehead's Process Philosophy of Education (Interchange, 26(4), pp. 341?415, 1995). In his criticism of those papers, George Allan (1998) claimed that the contributors to the Symposium were not as Whiteheadian as they thought they were because…

High-resolution continuous-flow analysis setup for water isotopic measurement from ice cores using laser spectroscopy

NASA Astrophysics Data System (ADS)

Emanuelsson, B. D.; Baisden, W. T.; Bertler, N. A. N.; Keller, E. D.; Gkinis, V.

2015-07-01

Here we present an experimental setup for water stable isotope (δ18O and δD) continuous-flow measurements and provide metrics defining the performance of the setup during a major ice core measurement campaign (Roosevelt Island Climate Evolution; RICE). We also use the metrics to compare alternate systems. Our setup is the first continuous-flow laser spectroscopy system that is using off-axis integrated cavity output spectroscopy (OA-ICOS; analyzer manufactured by Los Gatos Research, LGR) in combination with an evaporation unit to continuously analyze water samples from an ice core. A Water Vapor Isotope Standard Source (WVISS) calibration unit, manufactured by LGR, was modified to (1) enable measurements on several water standards, (2) increase the temporal resolution by reducing the response time and (3) reduce the influence from memory effects. While this setup was designed for the continuous-flow analysis (CFA) of ice cores, it can also continuously analyze other liquid or vapor sources. The custom setups provide a shorter response time (~ 54 and 18 s for 2013 and 2014 setup, respectively) compared to the original WVISS unit (~ 62 s), which is an improvement in measurement resolution. Another improvement compared to the original WVISS is that the custom setups have a reduced memory effect. Stability tests comparing the custom and WVISS setups were performed and Allan deviations (σAllan) were calculated to determine precision at different averaging times. For the custom 2013 setup the precision after integration times of 103 s is 0.060 and 0.070 ‰ for δ18O and δD, respectively. The corresponding σAllan values for the custom 2014 setup are 0.030, 0.060 and 0.043 ‰ for δ18O, δD and δ17O, respectively. For the WVISS setup the precision is 0.035, 0.070 and 0.042 ‰ after 103 s for δ18O, δD and δ17O, respectively. Both the custom setups and WVISS setup are influenced by instrumental drift with δ18O being more drift sensitive than δD. The σAllan

September 2011 DMM Podcast: an interview with Irv Weissman

PubMed Central

2011-01-01

SUMMARY This podcast includes excerpts from an interview with Irv Weissman, of Stanford University, in which he recalls his early years studying immunology in mice and discusses more recent challenges he has faced when attempting to develop stem-cell-based therapies with industry. Narrated by Sarah E. Allan. To listen to this podcast, visit http://www.biologists.com/DMM/podcasts/index.html.

New/Small News in the English Curriculum

ERIC Educational Resources Information Center

Sawyer, Wayne

2007-01-01

It has been argued that schools are trapped in a print-based past, while their students inhabit a nonprint-based age, and that this has accompanied a shift from traditional mass media to media driven by computer technology. This article draws on the work of Stuart Allan to examine some of the history of this shift in term of news and asks what…

Vantage Theory and Linguistic Relativity

ERIC Educational Resources Information Center

Allan, Keith

2010-01-01

Rob MacLaury's Vantage Theory, VT, models the way in which a cognizer constructs, recalls, uses, and modifies a category in terms of point of view or vantage. Alongside of VT, there is place for the kind of semantic specification found in the lexicon. VT2 [Allan, Keith, 2002. "Vantage theory, VT2, and number." "Language Sciences" 24(5-6), 679-703…

The DoD’s Use of Lowest Price Technically Acceptable (LPTA) Price Selection

DTIC Science & Technology

2013-09-01

Federal Aviation Administration had to resort to reducing the hours of its 47,000 employees, while the National Institutes of Health will issue...billion, including awards for forklifts for the Navy ($22.5 million), industrial hygiene services for a health clinic ($4.8 billion), and... overworked and understaffed. In submitted testimony to Congress, Allan Burman (Doing Business, 2012), President of Jefferson Solutions, which

Constructing Complexity: Using Reading Levels to Differentiate Reading Comprehension Activities

ERIC Educational Resources Information Center

FitzPatrick, Declan

2008-01-01

The author remembers a class when he asked his students to discuss in small groups how Edgar Allan Poe suggests a judgment of the main character in "The Cask of Amontillado". During their discussion it became clear to the author that the students couldn't come to consensus because they had no grasp of the narrator's explanations of his motivations…

Unit 1003: The Language of Exposition.

ERIC Educational Resources Information Center

Minnesota Univ., Minneapolis. Center for Curriculum Development in English.

This language unit for grade 10 builds on a definition of the expository use of language developed in the two previous 10th-grade units. In a brief overview of report language, the referential language of Thomas Huxley is compared with the expressive language of Edgar Allan Poe. The writings of S. I. Hayakawa, Hans Guth, and others are examined…

Between Heroes and Guardians: General Lyman L. Lemnitzer and General Charles H. Bonesteel III

DTIC Science & Technology

2015-05-21

16 David S. Patterson , Paul Claussen, Evan M. Duncan, Jeffrey A. Soukup, eds., Foreign Relations...Korea, 1966-1969, Leavenworth Papers no 19 (Fort Leavenworth: Combat Studies Institute, 1991); Amos A. Jordan, Jr ., Issues of National Security in...Representative in Europe, Mutual Security Program, Paris, France, 1952-53. 20 Allan R. Millett, Peter Maslowski, and William B. Feis, For the Common

Expert Approaches to Analysis

DTIC Science & Technology

1999-03-01

of epistemic forms and games , which can form the basis for building a tool to support expert analyses. 15. SUBJECT TERMS Expert analysis Epistemic...forms Epistemic games SECURITY CLASSIFICATION OF 16. REPORT Unclassified 17. ABSTRACT Unclassified 18. THIS PAGE Unclassified 19. LIMITATION OF...1998 Principal Investigators: Allan Collins & William Ferguson BBN Technologies Introduction 1 Prior Work 2 Structural-Analysis Games 2 Functional

Dynamics-Enabled Nanoelectromechanical Systems (NEMS) Oscillators

DTIC Science & Technology

2014-06-01

it becomes strongly nonlinear, and thus constitutes an archetypal candidate for nonlinear engineering • its fundamental resonant frequency...width of spectral peaks of atomic force microscopy (AFM) resonators as they are brought close to a surface. 39 Approved for public release...alternating current AD Allan Deviation AFM atomic force microscopy AFRL Air Force Research Laboratory AlN aluminum nitride APN Anomalous Phase

High Precision Ranging and Range-Rate Measurements over Free-Space-Laser Communication Link

NASA Technical Reports Server (NTRS)

Yang, Guangning; Lu, Wei; Krainak, Michael; Sun, Xiaoli

2016-01-01

We present a high-precision ranging and range-rate measurement system via an optical-ranging or combined ranging-communication link. A complete bench-top optical communication system was built. It included a ground terminal and a space terminal. Ranging and range rate tests were conducted in two configurations. In the communication configuration with 622 data rate, we achieved a two-way range-rate error of 2 microns/s, or a modified Allan deviation of 9 x 10 (exp -15) with 10 second averaging time. Ranging and range-rate as a function of Bit Error Rate of the communication link is reported. They are not sensitive to the link error rate. In the single-frequency amplitude modulation mode, we report a two-way range rate error of 0.8 microns/s, or a modified Allan deviation of 2.6 x 10 (exp -15) with 10 second averaging time. We identified the major noise sources in the current system as the transmitter modulation injected noise and receiver electronics generated noise. A new improved system will be constructed to further improve the system performance for both operating modes.

Impacts of PM concentrations on visibility impairment

NASA Astrophysics Data System (ADS)

Jie, Guo; Wang, Mei-mei; Han, Ye-Xing; Yu, Zhi-Wei; Tang, Huai-Wu

2016-11-01

In the paper, an accurate and sensitive cavity attenuated phase shift spectroscopy (CAPS) sensor was used to monitor the atmospheric visibility. The CAPS system mainly includes a LED light source, a band-pass filter, an optical resonant cavity (composed of two high mirror, reflectivity is greater than 99.99%), a photoelectric detector and a lock-in amplifier. The 2L/min flow rate, the optical sensor rise and fall response time is about 15 s, so as to realize the fast measurement of visibility. An Allan variance analysis was carried out evaluating the optical system stability (and hence the maximum averaging time for the minimum detection limit) of the CAPS system. The minima ( 0.1 Mm-1) in the Allan plots show the optimum average time ( 100s) for optimum detection performance of the CAPS system. During this period, the extinction coefficient was correlated with PM2.5 mass (0.88), the extinction coefficient was correlated with PM10 mass (0.85). The atmospheric visibility was correlated with PM2.5 mass (0.74). The atmospheric visibility was correlated with PM10 mass (0.66).

Chemical Attribution Signatures of Cyanogen Chloride from Commercial Sources

DTIC Science & Technology

2016-10-01

Biological Center Forensic Analytical Center members have performed purity analyses on >70 cylinders of cyanogen chloride (CK) procured from three different...Department of Homeland Security Chemical Forensics Program. The work was started in September 2012 and completed in August 2013. The use of...manufacturers; and  Timothy Allan, Alex Jestel, and other members of the ECBC Forensic Analytical Center for their expertise in CK analysis by

Airway Humidification During High-Frequency Percussive Ventilation

DTIC Science & Technology

2009-03-01

Airway Humidification During High-Frequency Percussive Ventilation Patrick F Allan MD, Michael J Hollingsworth CRT, Gordon C Maniere CRT, Anthony K...about the risk of inadequate humidification during high- frequency percussive ventilation (HFPV). METHODS: We studied 5 humidifiers during HFPV with a...50 L/min, and the ConchaTherm Hi-Flow with VDR nebulizer) provided carinal humidification equivalent to the comparator setup, without regard to

Serving the Cause: Duty Concepts and Combat Effectiveness in War

DTIC Science & Technology

2010-06-01

War II.10 Like moral factors, the notion of military effectiveness is complex and multi-faceted. Murray and Millet argue that military...The insights derived from this synthesis will provide the common reference point for analysis of the historical examples. Alan Millet and...1988). 4 Allan Millet and Williamson Murray, Military Effectiveness, Vol I, 2. 9 This dynamic interaction is particularly pronounced at the

Military Herald Indices (1975-1979). Volume 1.

DTIC Science & Technology

1988-11-01

Volume I Allan S . Rehm Lauren Van Metre Charles B. Hall DTICELECTE ________ § 12 19890 A Division of Hudson Institute CENTER FOR NAVAL ANALYSES 4401...DECLASSIFICATIONDOWNGRADING SCApproved for Public Release; Distribution Unlimited 4. PERFORMING ORGANIZATION REPORT NUMBER( S ) 5. MONITORING ORGANIZATION REPORT NUMBER( S ...Virginia 22302-0268 Washington, D.C. 20350-1000 S &. NAME OF FUNDING ORGANIZATION 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER

Military Suicide Research Consortium

DTIC Science & Technology

2015-10-01

physical and sexual abuse and lifetime number of suicide attempts: A persistent and theoretically important relationship. Behaviour Research & Therapy ...meeting of the Association of Behavioral and Cognitive Therapies , Chicago, IL. Norr, A. M., Allan, N. P., Macatee, R. J., Capron, D. W., & Schmidt, N. B...presentation to the annual Association for Behavioral and Cognitive Therapies conference, Chicago, IL. >>Dr. Craig Bryan had the following: Bryan, C.J

Possible Meteorites in the Martian Hills (False Color)

NASA Technical Reports Server (NTRS)

2006-01-01

From its winter outpost at 'Low Ridge' inside Gusev Crater, NASA's Mars Exploration Rover Spirit took this spectacular, color mosaic of hilly, sandy terrain and two potential iron meteorites. The two light-colored, smooth rocks about two-thirds of the way up from the bottom of the frame have been labeled 'Zhong Shan' and 'Allan Hills.'

The two rocks' informal names are in keeping with the rover science team's campaign to nickname rocks and soils in the area after locations in Antarctica. Zhong Shang is an Antarctic base that the People's Republic of China opened on Feb. 26, 1989, at the Larsemann Hills in Prydz Bay in East Antarctica. Allan Hills is a location where researchers have found many Martian meteorites, including the controversial ALH84001, which achieved fame in 1996 when NASA scientists suggested that it might contain evidence for fossilized extraterrestrial life. Zhong Shan was the given name of Dr. Sun Yat-sen (1866-1925), known as the 'Father of Modern China.' Born to a peasant family in Guangdong, Sun moved to live with his brother in Honolulu at age 13 and later became a medical doctor. He led a series of uprisings against the Qing dynasty that began in 1894 and eventually succeeded in 1911. Sun served as the first provisional president when the Republic of China was founded in 1912.

The Zhong Shan and Allan Hills rocks, at the left and right, respectively, have unusual morphologies and miniature thermal emission spectrometer signatures that resemble those of a rock known as 'Heat Shield' at the Meridiani site explored by Spirit's twin, Opportunity. Opportunity's analyses revealed Heat Shield to be an iron meteorite.

Spirit acquired this false-color image on the rover's 872nd Martian day, or sol (June 16, 2006), using exposures taken through three of the panoramic camera's filters, centered on wavelengths of 750 nanometers, 530 nanometers, and 430 nanometers. The image is presented in false color to emphasize differences among

Possible Meteorites in the Martian Hills

NASA Technical Reports Server (NTRS)

2006-01-01

From its winter outpost at 'Low Ridge' inside Gusev Crater, NASA's Mars Exploration Rover Spirit took this spectacular, color mosaic of hilly, sandy terrain and two potential iron meteorites. The two light-colored, smooth rocks about two-thirds of the way up from the bottom of the frame have been labeled 'Zhong Shan' and 'Allan Hills.'

The two rocks' informal names are in keeping with the rover science team's campaign to nickname rocks and soils in the area after locations in Antarctica. Zhong Shang is an Antarctic base that the People's Republic of China opened on Feb. 26, 1989, at the Larsemann Hills in Prydz Bay in East Antarctica. Allan Hills is a location where researchers have found many Martian meteorites, including the controversial ALH84001, which achieved fame in 1996 when NASA scientists suggested that it might contain evidence for fossilized extraterrestrial life. Zhong Shan was the given name of Dr. Sun Yat-sen (1866-1925), known as the 'Father of Modern China.' Born to a peasant family in Guangdong, Sun moved to live with his brother in Honolulu at age 13 and later became a medical doctor. He led a series of uprisings against the Qing dynasty that began in 1894 and eventually succeeded in 1911. Sun served as the first provisional president when the Republic of China was founded in 1912.

The Zhong Shan and Allan Hills rocks, at the left and right, respectively, have unusual morphologies and miniature thermal emission spectrometer signatures that resemble those of a rock known as 'Heat Shield' at the Meridiani site explored by Spirit's twin, Opportunity. Opportunity's analyses revealed Heat Shield to be an iron meteorite.

Spirit acquired this approximately true-color image on the rover's 872nd Martian day, or sol (June 16, 2006), using exposures taken through three of the panoramic camera's filters, centered on wavelengths of 600 nanometers, 530 nanometers, and 480 nanometers.

Unfocused Energy: A Strategic Approach to U.S. Communications in Afghanistan

DTIC Science & Technology

2010-05-21

of public relations through mass manipulation. Bernays professionally espoused the notion that in a democracy, the 14 Allan M . Winkler, The Politics...2009. 37 BIBLIOGRAPHY Al-Imarat, M . The Information Revolution and the Arab world: Its Impact on State and Society. Abu Dhabi, UAE, 1998...Dizard, W. P., The Strategy of Truth: The Story of the U.S. Information Agency, Washington D.C: Public Affairs Press, 1961. Donini , Antonio, Norah

Advances in Biotechnology and Genetic Engineering: Implications for the Development of New Biological Warfare Agents

DTIC Science & Technology

1996-06-01

GenPharm International, Inc. created the first transgenic dairy cow . The cow was used to produce human milk proteins for infant formula. 1990 A four...engineering techniques, biological compounds such as human insulin , growth hormone, and blood clotting factors can be produced in fermentors containing...the gene for rat insulin . 1977 Walter Gilbert and Allan Maxam at Harvard University devised a method for sequencing DNA using chemicals rather than

Vision to Victory - Space, Mahan, and Mitchell: The Role of the Visionary in Cross-Organizational Innovation

DTIC Science & Technology

2001-06-01

Mahan spent the latter part of 1885 and early 1886 in New York where the public library system provided access to quality resource materials.47...History, 1660-1783. Mineola, New York : Dover Publications , Inc., 1987. _____. The Interest of America in Sea Power, Present and Future. Freeport...7 Ibid., 251. 8 Williamson Murray and Allan R. Millet, eds., Military Innovation in the Interwar Period, ( New York : Cambridge University Press

High-Throughput Mosquito and Fly Bioassay System for Natural and Artificial Substrates Treated with Residual Insecticides

DTIC Science & Technology

2013-03-01

1989. Evaluation of the cotton fabric model for screening topical mosquito repellents . J Am Mosq Control Assoc 5:73–76. WHO [World Health Organization...institutions, research libraries, and research funders in the common goal of maximizing access to critical research. High-Throughput Mosquito and Fly Bioassay...A. Allan , Todd W. Walker , Christopher J. Geden , Jerome A. Hogsette , and Kenneth J. Linthicum Source: Journal of the American Mosquito Control

Soldier as a System Value Analysis

DTIC Science & Technology

2008-09-01

effort is to use established quantitative methods in the development of the framework and explore possible metrics for the assessment of applicable...and ease of use is an important part of the development of the holistic Soldier system. Small details can make a big difference to a Soldier in harsh...important (Friedl and Allan, 2004). Different kinds of environmental stressors include heat, cold, hypobaric hypoxia, physical work, energy

Cell biology. ER-to-Golgi traffic--this bud's for you.

PubMed

Brittle, E E; Waters, M G

2000-07-21

How do protein-transporting vesicles, which bud from the endoplasmic reticulum (ER), specifically dock to, and fuse with, the Golgi apparatus? In their Perspective, Brittle and Waters discuss new work (Allan et al.) suggesting that some vesicle-associated docking and fusion proteins are "programmed" during vesicle budding from the ER and direct downstream events that occur during fusion of these transport vesicles with the membranes of the Golgi.

Conference Proceedings: Aptitude, Learning, and Instruction. Volume 2. Cognitive Process Analyses of Learning and Problem Solving,

DTIC Science & Technology

1981-01-01

of a Complex System; 177 Albert L. Stevens and Allan Collins Introduction 177 Models 182 Conclusion 196 21. Complex Learning Processes 199 John R...have called schemata (Norman, Gentner, & Stevens , 1976), frames (Minsky, 1975), and scripts (Schank & Abelson, 1977). If these other authors are...York: McGraw-Hill. 1975. Norman, D. A.. Gcntner. D. R., & Stevens . A. L. Comments on learning schemata and memory representation. In D). K lahr (Ed

Acoustical Properties of Mud Sediments

DTIC Science & Technology

2015-09-30

Acoustical Properties of Mud Sediments Allan D. Pierce Boston University 399 Quaker Meeting House Road P. O. Box 339 East Sandwich, MA 03537...shallow-ocean mud sediments. Other goals are to assess prior data relating to the acoustic properties of mud and to provide guidance in the...development and interpretation of experiments. A related goal is to construct models that will guide inversion techniques for inferring properties of mud

Air Bursting Munition ABM Medium Calibre Applications

DTIC Science & Technology

2001-04-18

NDIA 45th Annual Fuze Conference - Long Beach, CA - April 16-18, 2001 Folie 1 P2 15548 BB, P-VP/FD/11, © 2001 Oerlikon Contraves AG, Zürich...Switzerland Air Bursting Munition ABM Medium Calibre Applications Allan Buckley & Pierre Freymond Oerlikon Contraves Pyrotec AG CH-8050 Zurich...Project Number Task Number Work Unit Number Performing Organization Name(s) and Address(es) Oerlikon Contraves Pyrotec AG CH-8050 Zurich / Switzerland

Researchers unmask secret to long-lasting effects of botulinum neurotoxin A in motor neurons | Center for Cancer Research

Cancer.gov

A team of scientists led by the Center for Cancer Research's Allan M. Weissman, M.D., and Yien Che Tsai, Ph.D., has discovered a molecular mechanism that explains the extreme toxicity of botulinum neurotoxin A (BoNT/A), the most potent BoNT strain. The discovery, published June 5 in PNAS, also identifies a molecular target that the researchers hope will eventually lead to

Construction Management Planning. The Impact on Meeting Owner Goals.

DTIC Science & Technology

1984-05-17

study, the CM company’s effectiveness was more a -4D Wd. .-. * *J 6 i David Allan Boothe result of an interaction of organizational and environmental ... company’s environmental concerns is when the firm is hired and the control it has over the establishment !S .. . . . . . . . . . . . . 51 *i- of the...significant relationship when either environmental or environmental / planning characteristics were controlled. What was indicated as being significant

Has the Dayton Peace Agreement Stopped Progress in Bosnia and Herzegovina?

DTIC Science & Technology

2013-03-01

Headquarters Services , Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302...and lengthen economic recovery . 5 As a result of the atrocities of WWII, there was tremendous effort to define the treatment of non...Department of the Army, August 1, 2012), iii. 6 Laura Silber and Allan Little, Yugoslavia Death of a Nation (New York: Penguin, 1997), 29. 7 Richard

Annals of the New York Academy of Sciences. Volume 423. Timing and Time Perception Held at New York on 10-13 May 1983,

DTIC Science & Technology

1984-05-13

PART L TIME PERCEPTION Introduction JOHN GIBBON W. New York State Psychiatric Institute New York, New York 10032; and Department of Psychology ...34."’ Columbia University New York, New York 10027 LORRAINE ALLAN Department of Psychology McMaster University Hamilton, Ontario, Canada LAS 4Ki The study...of timing and time perception has a venerable dual history in experimental psychology . Animal psychologists studying learning and conditioning have

Psychological and Organizational Climate: Dimensions and Relationships

DTIC Science & Technology

1977-03-07

SPSYCHOLOGICAL AND ON IZATIONAL CUMATE: DIESINSAND RELATINSI’ K0 A. P. INES L . R. JAMES REPWIINO 77-12 N(AVAL HEALTH RESEARCH CENTER SAN DIEGO...CALIFORNIA 92152 a NAVAL MEDICAL RESEARCH AND DEVELOPMENT COMMAND BhEThESDA1 MARYLAND Psychological and Organizational Climate: Dimensions and...Relationships Allan P. Jones Naval Health Research Center San Diego, California 92152 and Lawrence R. James Institute of Behavioral Research Texas Christian

Atomic clocks and the continuous-time random-walk

NASA Astrophysics Data System (ADS)

Formichella, Valerio; Camparo, James; Tavella, Patrizia

2017-11-01

Atomic clocks play a fundamental role in many fields, most notably they generate Universal Coordinated Time and are at the heart of all global navigation satellite systems. Notwithstanding their excellent timekeeping performance, their output frequency does vary: it can display deterministic frequency drift; diverse continuous noise processes result in nonstationary clock noise (e.g., random-walk frequency noise, modelled as a Wiener process), and the clock frequency may display sudden changes (i.e., "jumps"). Typically, the clock's frequency instability is evaluated by the Allan or Hadamard variances, whose functional forms can identify the different operative noise processes. Here, we show that the Allan and Hadamard variances of a particular continuous-time random-walk, the compound Poisson process, have the same functional form as for a Wiener process with drift. The compound Poisson process, introduced as a model for observed frequency jumps, is an alternative to the Wiener process for modelling random walk frequency noise. This alternate model fits well the behavior of the rubidium clocks flying on GPS Block-IIR satellites. Further, starting from jump statistics, the model can be improved by considering a more general form of continuous-time random-walk, and this could bring new insights into the physics of atomic clocks.

Noise and drift analysis of non-equally spaced timing data

NASA Technical Reports Server (NTRS)

Vernotte, F.; Zalamansky, G.; Lantz, E.

1994-01-01

Generally, it is possible to obtain equally spaced timing data from oscillators. The measurement of the drifts and noises affecting oscillators is then performed by using a variance (Allan variance, modified Allan variance, or time variance) or a system of several variances (multivariance method). However, in some cases, several samples, or even several sets of samples, are missing. In the case of millisecond pulsar timing data, for instance, observations are quite irregularly spaced in time. Nevertheless, since some observations are very close together (one minute) and since the timing data sequence is very long (more than ten years), information on both short-term and long-term stability is available. Unfortunately, a direct variance analysis is not possible without interpolating missing data. Different interpolation algorithms (linear interpolation, cubic spline) are used to calculate variances in order to verify that they neither lose information nor add erroneous information. A comparison of the results of the different algorithms is given. Finally, the multivariance method was adapted to the measurement sequence of the millisecond pulsar timing data: the responses of each variance of the system are calculated for each type of noise and drift, with the same missing samples as in the pulsar timing sequence. An estimation of precision, dynamics, and separability of this method is given.

Decisively Avoiding Defeat: Strategy, the Operational Artist, and Limited War

DTIC Science & Technology

2016-05-26

Allan R. Millett, The War For Korea , 1950 – 1951: They Came from the North (Lawrence, KS: University of Kansas Press, 2010), 60. 10 Communist...security, but could not attack the Communist North and upset the balance.86 The US limited policy toward Korea to support European commitments. This...78. 105 Millett, The War for Korea , 132. 30 action by the 24th Infantry Division failed to stop the North Koreans. MacArthur understood the

Protecting Critical Rail Infrastructure

DTIC Science & Technology

2006-12-01

Gulliver.Trb.Org/Publications/Sr/Sr270.Pdf. 38. Allan J. DeBlasio, Terrance J. Regan, Margaret E . Zirker, Katherine S. Fichter, Kristin Lovejoy ...getrpt?GAO-04-598T. 4. Ibid. 5. Thomas H. Kean, Lee H. Hamilton, Richard Ben-Veniste, Fred F. Fielding, Jamie S. Gorelick, Slade Gorton, Bob Kerrey...Committee, Current and Projected National Security Threats to the United States, Vice Admiral Lowell E . Jacoby, United States Navy, Director, Defense

Natural analogs in the petroleum industry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wood, J.R.

1995-09-01

This article describes the use of natural analogues in petroleum exploration and includes numerous geologic model descriptions which have historically been used in the prediction of geometries and location of oil and gas accumulations. These geologic models have been passed down to and used by succeeding generations of petroleum geologists. Some examples of these geologic models include the Allan fault-plane model, porosity prediction, basin modelling, prediction of basin compartmentalization, and diagenesis.

Family Traits of Galaxies: From the Tuning Fork to a Physical Classification in a Multi-Wavelength Context

NASA Astrophysics Data System (ADS)

Rampazzo, Roberto; D'Onofrio, Mauro; Zaggia, Simone; Elmegreen, Debra M.; Laurikainen, Eija; Duc, Pierre-Alain; Gallart, Carme; Fraix-Burnet, Didier

At the time of the Great Debate nebulæ where recognized to have different morphologies and first classifications, sometimes only descriptive, have been attempted. A review of these early classification systems are well documented by the Allan Sandage's review in 2005 (Sandage 2005). This review emphasized the debt, in term of continuity of forms of spiral galaxies, due by the Hubble's classification scheme to the Reynold's systems proposed in 1920 (Reynolds, 1920).

Swarming Mechanisms in the Yellow Fever Mosquito: Aggregation Pheromones are Involved in the Mating Behavior of Aedes aegypti

DTIC Science & Technology

2014-12-01

behavior of Aedes aegypti Emadeldin Y. Fawaz1, Sandra A. Allan2, Ulrich R. Bernier2, Peter J. Obenauer3, and Joseph W. Diclaro II1 1Vector Biology... Aedes aegypti swarming behavior and identified associated chemical cues. Novel evidence is provided that Ae. aegypti females aggregate by means of...the isolated aggregation pheromones in controlling Ae. aegypti. Journal of Vector Ecology 39 (2): 347-354. 2014. Keyword Index: Aedes aegypti, swarm

Military Herald Indices (1975-1979). Volume 2

DTIC Science & Technology

1988-11-01

KALININ,V.COL., S "YEDIN.S.ENGR.LC.CTS. 1977 APR TRAINER EXERCISE.: KISELEV.P.. SHILOV.A. 1976 FEB TRAINER FOR FIRING TRAINING; A CLASSROOM .: YAROSHEVSKIY,V...Military Herald Indices (1975-1979) 0 C\\I Volume I! Allan S . Rehm Lauren Van Metre Charles B. Hall DTIC ELECTE JUN 02 1989 A Division of Hudson...AVAILABILITY OF REPORT . DECLASSIFIATIN /Approved for Public Release; Distribution unlimited 4. PERFORM NG ORGANIZATION REPORT NUMBER( S ) S . MONITORING

Conversion of Low Quality Waste Heat to Electric Power with Small-Scale Organic Rankine Cycle (ORC) Engine/Generator Technology

DTIC Science & Technology

2016-06-01

Allan Robichaux, DPW PWD GTMO and the management and staff of the GTMO on site contractor , Centerra. Page Intentionally Left Blank ii Table of...operations and maintenance contractor to ensure that data transfers are completed as required. Figure 4 shows the location of the ORC installation on MUSE...this issue with telephone support from CRM’s controls contractor (Winn-Marion, W-M); however, the problem remained unresolved as of Sept. 1 when

International Infantry and Joint Services Small Arms Systems Section Symposium, Exhibition and Firing Demonstration. Held in Atlantic City, NJ on 13-16 May 2002. Volume 2

DTIC Science & Technology

2002-05-13

Atlantic Council NATO Army Armaments Group 30mm x 173 Ammunition Family by Allan Buckley & Pierre H. Freymond, Oerlikon Contraves Pyrotec AG Thursday, 16 May...actual weapon w/o adding weight • Compatible with LASER-activated battle simulators (MILES) 5.56mm FX - NDIA 2002.PPT (15.05.02) (11) FX® Marking...construction and design – Packaging inspection – Interfaces – Weight – Final protective finish – Endurance at ambient – Rough handling – Workmanship

A digitally implemented phase-locked loop detection scheme for analysis of the phase and power stability of a calibration tone

NASA Technical Reports Server (NTRS)

Densmore, A. C.

1988-01-01

A digital phase-locked loop (PLL) scheme is described which detects the phase and power of a high SNR calibration tone. The digital PLL is implemented in software directly from the given description. It was used to evaluate the stability of the Goldstone Deep Space Station open loop receivers for Radio Science. Included is a derivative of the Allan variance sensitivity of the PLL imposed by additive white Gaussian noise; a lower limit is placed on the carrier frequency.

Observations of tropospheric phase scintillations at 5 GHz on vertical paths

NASA Technical Reports Server (NTRS)

Armstrong, J. W.; Sramek, R. A.

1982-01-01

The article presents observations of turbulence-induced tropospheric phase fluctuations measured at 5 GHz on the near-vertical paths relevant to many astronomical and geophysical measurements. The data are summarized as phase power spectra, structure functions, and Allan variances. Comparisons to other microwave observations indicate relatively good agreement in both the level and shape of the power spectrum of these tropospheric phase fluctuations. Implications for precision Doppler tracking of spacecraft and geodesy/radio interferometry are discussed.

Committees

NASA Astrophysics Data System (ADS)

2010-01-01

INTERNATIONAL ADVISORY COMMITTEE FOR POSITRON WORKSHOP Roberto S Brusa (Italy) Michael Charlton (UK) Arnab S Ghosh (India) Franco A Gianturco (Italy) Gleb F Gribakin (UK) John Humberston (UK) Helge Knudsen (Denmark) Akos Kover (Hungary) Gaetana Laricchia (UK) Marco AP Lima (Brazil) Allen Mills (USA) Yasuyuki Nagashima (Japan) Clifford M Surko (USA) James Walters (UK) Sandra Ward (USA) LOCAL ORGANIZING COMMITTEE FOR POSITRON WORKSHOP Radu I Campeanu (York, Chairman) Jurij W Darewych (York) Allan D Stauffer (York) Cody Storry (York)

Deterrence and Influence: The Navy’s Role in Preventing War. Revision 1

DTIC Science & Technology

2009-03-01

are designed to influence actors at the earliest phases of the conflict spectrum. Our objective is to analyze how U.S. non-nuclear capabilities can...34 Foreign Affairs (Fall 1991), pp. 66-82; Paul H. Nitze, "Is It Time to Junk Our Nukes?" Washington Post , 16 January 1994, p. Cl; Charles T. Allan...gain new insights and test our ideas. We consulted with SMEs from CNA, IDA, OPNAV, OSD, USSTRATCOM, academic institutions, and various think tanks

Envelope of Correlation Used with Deconvolution and Reconvolution to Remove the Direct Arrival in a Multipath Environment

DTIC Science & Technology

1990-03-01

London - Amsterdam:Geophysical Press, 1984. 3 Dicus, Ronald L., "Impulse response estimation with underwater explosive charge acoustic signals," Journal of... Ronald N. Bracewell, The Fourier Transform and Its Applications. New York: McGraw-Hill, 1978, pp 267-71. 6 Julius S. Bendat and Allan G. Pierson...Feuillade Code 212 Ted Kennedy L. Dolly Lee Code 240 Dr. Ron Wagstaff 833 Hancock Sq., Suite G Dr. Robert Farwell Bay St. Louis, MS 39520 Code 242 Roger

Geochemical and Rheological Constraints on the Dynamics of the Oceanic Upper Mantle

DTIC Science & Technology

2007-09-01

405-412. 201 Dick, H. J. B., Natland, J., Party, L. . S., 1994. Melt transport and evolution in the shallow mantle beneath the East Pacific Rise ...in the shallow mantle beneath the East Pacific Rise . In: M6vel, C., Gillis, K. M., Allan, J. F., Meyer, P. S. (Eds.), Proceedings of the Ocean...according to ridge location: East Pacific Rise (EPR), Mid-Cayman Rise (MCR), Central Indian Ridge/Carlsberg Ridge (CIR/Carl), Mid-Atlantic Ridge (MAR

Investigation of Optical Fibers for Coherent Anti-Stokes Raman Scattering (CARS) Spectroscopy in Reacting Flows (Postprint)

DTIC Science & Technology

2012-03-01

applications. Springer, Netherlands Pronko PP, VanRompay PA, Horvath C, Loesel F, Juhasz T, Liu X, Mourou G (1998) Avalanche ionization and dielectric Exp...Birks TA, Russell PSJ, Roberts PJ, Allan DC (1999) Single-mode photonic band gap guidance of light in air. Science 285:1537–1539 Du D, Liu X, Mourou G ...Lowdermilk WH, Milam D (1984) Review of ultraviolet damage threshold measurements at Lawrence Livemore National Labo- ratory. Proc SPIE 476:143–162 Mann G

The Evolution of Los Zetas in Mexico and Central America: Sadism as an Instrument of Cartel Warfare

DTIC Science & Technology

2014-04-01

investment, tourism , natural resources, migration, energy, and se- curity. In recent years, narco-violence has afflicted our neighbor to the south...Italy, the Yakuza mob in Japan, and the Brothers’ Circle of Eastern Europe.20 The author was cautioned not to even utter the word “Zeta” aloud when...then returned to Cobán, grabbed the son of local official Allan Stowlinsky Vidaurre, and cut him into small pieces. The word was unambiguous: “We 15

Digital signal processing in the radio science stability analyzer

NASA Technical Reports Server (NTRS)

Greenhall, C. A.

1995-01-01

The Telecommunications Division has built a stability analyzer for testing Deep Space Network installations during flight radio science experiments. The low-frequency part of the analyzer operates by digitizing wave signals with bandwidths between 80 Hz and 45 kHz. Processed outputs include spectra of signal, phase, amplitude, and differential phase; time series of the same quantities; and Allan deviation of phase and differential phase. This article documents the digital signal-processing methods programmed into the analyzer.

The Korean Military Advisory Group -- Developmental Challenges during Ongoing Conflict

DTIC Science & Technology

2013-05-23

from the North ( Lawrence , KS: University Press of Kansas, 2010), 304-305. Allen Millett describes in great detail the maneuver techniques implemented...in Korea, 1946-1948: The Intelligent Man on the Spot,” 192; Allan R. Millett, “Captain James H. Hausman and the Formation of the Korean Army, 1945...Oberdorfer retold a story of a prominent military strategist, Colonel Harry Summers , who stated, “…arriving for duty as a US Army private and being

Korean Military Advisory Group: Insights for Future Security Force Assistance Efforts

DTIC Science & Technology

2011-06-10

49Hudson, Interview. 50Clemens, ―Captain James Hausman ,‖ 176; Allan Millett, The War For Korea: 1945-1950: A House Burning ( Lawrence , KS...officer T. E. Lawrence came to the same conclusion dealing with Arabs during World War I. Concluding during his time as an advisor in Arabia that ―it is...on the future army of South Korea. In July 1946, Captain James H. Hausman was assigned to USAMGIK as an advisor to the Eighth Constabulary Regiment

Deciding What Has to Be Done: General William E. DePuy and the 1976 Edition of FM 100-5, Operations (Leavenworth Paper, Number 16)

DTIC Science & Technology

1988-07-01

Teaching Committee LTC Charles D . McKenna, Chief LTC John R . Finch MAJ Stephen D . Coats LTC Andrew N. Morris MAJ Robert E. Gillespie LTC Edward P...Cheryl J. Davis, Editorial Assistant Staff MSG Russell E. Miller Jr. Joan R . Bazajou SSG Patricia E. Clowers Carolyn D . Conway Sharon E. Torres...from Professor Allan R . Millett, The Ohio State University; Colonel Robert A. Doughty (U.S. Army), U.S. Military Academy; and Dr. Roger D . Spiller

A Quadrotor Sensor Platform

DTIC Science & Technology

2008-08-01

quadrotor with two planes of symmetry. As a reference, a blue flag was fixed to one arm to mark the tail. y z inertial frame x y z body frame x N...Vermont, 1976. [5] Charles Gablehouse. Helicopters and Autogiros. J. B. Lippencott Company, Philadelphia, 1969. [6] C. V. Glines. “The Flying Octopus ...and Darryll J. Pines. “Characterization of Ring Laser Gyro Performance Using the Allan Variance Method”. Journal of Guidance, Control, and Dynamics, vol

Proceedings of the Tenth Annual National Conference on Ada Technology. Held in Arlington, VA, on February 24-28, 1992

DTIC Science & Technology

1992-02-01

Newsletter, Vol. 5, No. 1, January 1983 be translated from HAL’S. 4. Klumpp, Allan R., An Ada Linear Algebra Software development costs for using the...a linear algebra approach to As noted above, the concept of the problem and address the problem of unitdimensional analysis extends beyond problems...you will join us again next year. The 11th Annual Conference on Ada Technology (1993) will be held here at the Hyatt Regency - Crystal City

Response to "Alternative Measures of School District Wealth" by Allan Odden

ERIC Educational Resources Information Center

Johns, Roe L.

1977-01-01

Argues against John's suggestion that state equalization aid to local school districts should be based on measures of per-capita income and assessed property valuation per capita, rather than on measures of local tax revenue and assessed property valuation per pupil. (JG)

The Use of Long Acting Reversible Contraceptives and the Relationship between Discontinuation Rates due to Menopause and to Female and Male Sterilizations.

PubMed

Ferreira, Jessica Mayra; Monteiro, Ilza; Castro, Sara; Villarroel, Marina; Silveira, Carolina; Bahamondes, Luis

2016-05-01

Introduction Women require effective contraception until they reach menopause. The long acting reversible contraceptives (LARC) and the depot-medroxyprogesterone acetate (DMPA, Depo-Provera®, Pfizer, Puurs, Belgium) are great options and can replace possible sterilizations. Purpose To assess the relationship between the use of LARCs and DMPA and terminations ascribed to menopause and sterilizations in a Brazilian clinic. Methods We reviewed the records of women between 12 and 50 years of age attending the clinic that chose to use a LARC method or DMPA. Cumulative termination rates due to sterilization or because the woman had reached menopause were computed using single decrement life-table analysis over 32 years. We also examined all records of surgical sterilization at our hospital between the years 1980-2012. Results Three hundred thirty-two women had continuously used the same contraceptive until menopause, and 555 women had discontinued the method because they or their partners underwent sterilization. From year 20 to year 30 of use, levonorgestrel intrauterine-releasing system (LNG-IUS - Mirena®, Bayer Oy, Turku, Finland; available since 1980), copper intrauterine device (IUD - available since 1980) and DMPA users showed a trend of cumulative higher discontinuation rates due to menopause when compared with the discontinuation rates due to sterilization. Over the study period, a steep decline in the use of sterilization occurred. Conclusion Over the past 15 years of research we have observed a trend: women usually preferred to continue using LARC methods or DMPA until menopause rather than decide for sterilization, be it their own, or their partners'. The annual number of sterilizations dropped in the same period. The use of LARC methods and DMPA until menopause is an important option to avoid sterilization, which requires a surgical procedure with potential complications. Thieme Publicações Ltda Rio de Janeiro, Brazil.

Optical fibers for the distribution of frequency and timing references

NASA Technical Reports Server (NTRS)

Lutes, G. F.

1981-01-01

An optical fiber communications link was installed for the purpose of evaluating the applicability of optical fiber technology to the distribution of frequency and timing reference signals. It incorporated a 1.5km length of optical fiber cable containing two multimode optical fibers. The two fibers were welded together at one end of the cable to attain a path length of 3km. Preliminary measurements made on this link, including Allan variance and power spectral density of phase noise are reported.

Maritime Infrared Propagation: Particle Size Distribution Measurements Using a Helicopter-Borne Aerosol Counter.

DTIC Science & Technology

1981-09-01

COUNTER by R. R. Allan S. Craig SUMMARY -Particle size distribution measurements were made on nine successive days in late August 1980 using a PMS FSSP-100...aerosol counter flown on a Wessex Mk 5 helicopter. In all, 14 flights were made giving data at two heights, 30 and 100 ft above the sea surface...aerosol content over deep water. It was a specific recommendation of TTCP-JAG9 that airborne aerosol measurements should be made in conjunction with al

13. Photocopy of a photographca. 1896showing wooden arch bridge over ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

13. Photocopy of a photograph--ca. 1896--showing wooden arch bridge over the North Fork of the San Joaquin River northeast of Fresno, CA. This structure was designed by Eastwood as part of the San Joaquin Electric Company's hydro-electric plant; it is a design that indicates his interest in the structural capabilities of the arch before he began building multiple arch dams. Courtesy Mr. Charles Allan Whitney. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

[Book review] The known birds of North and Middle America: Distribution and variation, migrations, changes, hybrids, etc, Part I, Hirundinidae to Mimidae, Certhiidae

USGS Publications Warehouse

Banks, Richard C.; Phillips, R.

1991-01-01

"Known Birds" is the culmination of Allan Phillips' long and productive career in elucidating the taxonomy and relationships of North American, particularly Mexican, birds. It reflects many years of largely independent work in the field, museum, and library. Although Part I includes contributions by Robert W. Dickerman, Amadeo M. Rea, and J. Dan Webster, the series (Part II will be available by the time this long-overdue review of Part I appears) reflects Phillips' views of avian systematics and his idiosyncratic scientific philosophy.

Preparing the Fleet for the F-35B

DTIC Science & Technology

2012-02-06

from forward sites, a similar argument was made in the early 1970s by the “ plank holders” of the AV-8B program. vi In the Spring of 2010, USMC...Flying Shame.” Such press caused significant concern in the USMC’s leadership to attempt and mitigate possible risk in the operation of the aircraft...www.armedforcesjournal.com/2010/10/4765181/ (accessed January 14, 2012). Sack, Kevin and Allan C. Miller. “An Abundance of Crash-Causing Glitches.” Los Angeles

Longstreet’s Corps at Chickamauga: Lessons in Inter-Theater Deployment.

DTIC Science & Technology

1985-06-07

CATALOG NUmBt R 4. TITLE (end Subtitle) S. 7YPE OF REPORT & PERIOD COVERED LOT-EEST’S CORPS AT CHICKA1MAUGA: TESS IT: I:;TER-TI EAE DEPLOY’>IETT ’-ASTER’.3s...Allan R . Millott and Peter Maslow.ski, For the Comon Defense. (Now York: The Free Press, 1984), p. 157. Figure 2, 4, 5. Drawn by Maj. Jet Skeele...may allow us to *...... .. . . . .o-. .o. .,.. o.. ,-o. .- •° o o ...... . . ...... - . .- . , .~ rr - r ~ - r ’ . .. . .. -ś- apply our past

The Autonomous Cryocooled Sapphire Oscillator: A Reference for Frequency Stability and Phase Noise Measurements

NASA Astrophysics Data System (ADS)

Giordano, V.; Grop, S.; Fluhr, C.; Dubois, B.; Kersalé, Y.; Rubiola, E.

2016-06-01

The Cryogenic Sapphire Oscillator (CSO) is the microwave oscillator which feature the highest short-term stability. Our best units exhibit Allan deviation σy (τ) of 4.5x10-16 at 1s, ≈ 1.5x10-16 at 100 s ≤ t ≤ 5,000 s (floor), and ≤ 5x10-15 at one day. The use of a Pulse-Tube cryocooler enables full two year operation with virtually no maintenance. Starting with a short history of the CSO in our lab, we go through the architecture and we provide more details about the resonator, the cryostat, the oscillator loop, and the servo electronics. We implemented three similar oscillators, which enable the evaluation of each with the three- cornered hat method, and provide the potential for Allan deviation measurements at parts of 10-17 level. One of our CSOs (ULISS) is transportable, and goes with a small customized truck. The unique feature of ULISS is that its σy (τ) can be validated at destination by measuring before and after the roundtrip. To this extent, ULISS can be regarded as a traveling standard of frequency stability. The CSOs are a part of the Oscillator IMP project, a platform dedicated to the measurement of noise and short-term stability of oscillators and devices in the whole radio spectrum (from MHz to THz), including microwave photonics. The scope spans from routine measurements to the research on new oscillators, components, and measurement methods.

Analysis of VIIRS TEB noise using solar diffuser measurements

NASA Astrophysics Data System (ADS)

Choi, Taeyoung; Cao, Changyong; Weng, Fuzhong

2015-09-01

The Soumi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) was launched on October 28th, 2011 and its Sensor Data Record (SDR) product reached maturity status in March of 2014. Although the VIIRS SDR products are declared at the validated maturity level, there remain issues such as residual stripings in some thermal bands along with the scan direction. These horizontal striping issues in the Thermal Emissive Bands (TEB) were reflected in the sea surface temperature (SST) products. The observed striping magnitude can reach to 0.2 K, especially at the band M14 and M15. As an independent source of calibration, the Solar Diffuser (SD) is utilized in this study. The SD is originally designed for the Reflective Solar Band (RSB), however, it is assumed to be thermally stable at the time of SD observation. For each detector, a linear slope is developed by Integrated Calibration and Validation System (ICVS), which is applied on converting digital number (DN) to radiance unit. After the conversion, detector based noise analyses in VIIRS band M15 and M16 are performed on in-scan and scan-by-scan SD responses. Since SD radiance varies within an orbit, the noise calculation must be derived from the neighborhood Allan deviation. The noise derived Allan deviation shows that detector 1 and 2 in band M15 and detector 9 in band M16 have higher noise content compared to other detectors.

Allan Bakke versus Regents of the University of California. Volumes I-VI.

ERIC Educational Resources Information Center

Slocum, Alfred A., Ed.

The complete record of the litigation in Alan Bakke v. The Regents of the University of California is contained in these six volumes. Included are all the pleadings, briefs, and arguments reproduced in full text except for minor editing of the oral arguments and data pertaining to the proof of service affidavits of truths. Volume One contains the…

Waterjet Propulsor Performance Prediction in Planing Craft Applications

DTIC Science & Technology

1979-08-01

APPLICATIONS - •by U Stephen B. Denny and Allan R. Feller rr *W Ft•i ; 1 0 t ........ ¢J J SHIP PERFORMANCE DEPARTMENT DEPARTMENTAL REPORT 04 :August 1979...FORM 1 . OVT ACCESSIONN’O. I. RECiPlINT1 CATALOG MUMIEM /DTNSRDVSP~95-01 N)’ att~~’~ YATERJETYCOPULSOR TERIORMANC ___o __a jf-- • -- • . ........ . / T...PUqjAWj T.FI *PRG~ TASK David W. Taylor Naval Ship R&D Center Work .equtj Bethesda, Maryland 20084 0080 __Work Unit 1 -1532-600 11, CONTROLtLING OPFICE

Simulation Study Using a New Type of Sample Variance

NASA Technical Reports Server (NTRS)

Howe, D. A.; Lainson, K. J.

1996-01-01

We evaluate with simulated data a new type of sample variance for the characterization of frequency stability. The new statistic (referred to as TOTALVAR and its square root TOTALDEV) is a better predictor of long-term frequency variations than the present sample Allan deviation. The statistical model uses the assumption that a time series of phase or frequency differences is wrapped (periodic) with overall frequency difference removed. We find that the variability at long averaging times is reduced considerably for the five models of power-law noise commonly encountered with frequency standards and oscillators.

Researchers unmask secret to long-lasting effects of botulinum neurotoxin A in motor neurons | Center for Cancer Research

Cancer.gov

A team of scientists led by the Center for Cancer Research's Allan M. Weissman, M.D., and Yien Che Tsai, Ph.D., has discovered a molecular mechanism that explains the extreme toxicity of botulinum neurotoxin A (BoNT/A), the most potent BoNT strain. The discovery, published June 5 in PNAS, also identifies a molecular target that the researchers hope will eventually lead to improved therapies to treat exposure and severely undermine the potential use of BoNTs as bioweapons.  Read more...  

Geodetic positioning of the Aerospace Electronics Research Lab (ERL) Osborne Time Transfer Receiver (TTR) using the GPS NAVSTAR Block I satellites

NASA Technical Reports Server (NTRS)

Liu, Anthony S.

1990-01-01

Aerospace has routinely processed the Osborne Time Transfer Receiver (TTR) data for the purpose of monitoring the performance of ground and GPS atomic clocks in near real-time with on-line residual displays and characterizing clock stability with Allan Variance calculations. Recently, Aerospace added the ability to estimate the TTR's location by differentially correcting the TTR's location in the WGS84 reference system. This new feature is exercised on a set of TTR clock phase data and Sub-meter accurate station location estimates of the TTR at the Aerospace Electronic Research Lab (ERL) are obtained.

Programmable frequency reference for subkilohertz laser stabilization by use of persistent spectral hole burning.

PubMed

Sellin, P B; Strickland, N M; Carlsten, J L; Cone, R L

1999-08-01

We report what is believed to be the first demonstration of laser frequency stabilization directly to persistent spectral holes in a solid-state material. The frequency reference material was deuterated CaF(2): Tm(3+) prepared with 25-MHz-wide persistent spectral holes on the H(6)(3)?H(4)(3) transition at 798 nm. The beat frequency between two lasers that were independently locked to persistent spectral holes in separate crystal samples showed typical root Allan variances of 780+/-120Hz for 20-50-ms integration times.

Workshop on the Issue Martian Meteorites: Where do we Stand and Where are we Going?

NASA Technical Reports Server (NTRS)

1998-01-01

The presentations in this workshop discuss the composition of Martian meteorites. Many of the talks were on a specific meteorite, i.e., Allan Hills 84001 (ALH84001). The discovery earlier of carbonates in ALH84001 lead some researchers to suggest that there was evidence of martian life. Other possible explanations for this phenomena are given. Other papers discuss methods to sterilize martian samples, the existence of water on Mars, the facilities of the Meteorite Processing Laboratory at Johnson Space Center, comparative analyses of geologic processes and the gathering of meteorites.

Recent results of the pulsed optically pumped rubidium clock

NASA Astrophysics Data System (ADS)

Levi, F.; Micalizio, S.; Godone, A.; Calosso, C.; Bertacco, E.

2017-11-01

A laboratory prototype of a pulsed optically pumped (POP) clock based on a rubidium cell with buffer gas is described. This clock has shown very interesting physical and metrological features, such as negligible light-shift, strongly reduced cavity-pulling and very good frequency stability. In this regard, an Allan deviation of σy(τ) = 1.2 τ-1/2 for measurement times up to τ = 105 s has been measured. These results confirm the interesting perspectives of such a frequency standard and make it very attractive for several technological applications, such as radionavigation.

Atomic clocks based on extened-cavity diode laser in multimode operation

NASA Astrophysics Data System (ADS)

Yim, Sin; Cho, D.

2011-05-01

We demonstrated the possibilities to develope an atomic clock based on coherent population trapping (CPT) without using a local oscillator and a modulator. Instead of using a modulator, we use two modes from a single extended-cavity diode laser in multimode operation. Two different types of feedback system are applied to stabilize a difference frequency between the two modes and eliminate the need for an extra frequency modulation. In the first type, we employ an electronic feedback using dispersion of the CPT resonance as an error signal. The two modes are phase locked with reference to a dispersion signal from a CPT resonance of 85Rb at 3.036 GHz ground hyperfine splitting. We use D1 transition at 794.8 nm with lin ⊥lin polarizations to obtain large-contrast CPT signal. Allan deviation of the beat frequency between the two modes is 1 ×10-10 at 200-s integration time. In the second type, we employ optoelectronic feedback to construct an opto-electronic oscillator (OEO). In an OEO, the beating signal between two modes is recovered by a fast photodiode, and its output is amplified and fed back to the laser diode by using a direct modulation of an injection current. When the OEO loop is closed, oscillation frequency depends on variations of the loop length. In order to stabilize an OEO loop length and thereby its oscillation frequency, CPT cell is inserted to play a role of microwave band pass filter. Allan deviation of the CPT-stabilized OEO is 2 ×10-10 at 100-s integration time.

Mid-infrared dual-gas sensor for simultaneous detection of methane and ethane using a single continuous-wave interband cascade laser

DOE PAGES

Ye, Weilin; Li, Chunguang; Zheng, Chuantao; ...

2016-07-18

A continuous-wave (CW) interband cascade laser (ICL) based mid-infrared sensor system was demonstrated for simultaneous detection of atmospheric methane (CH 4) and ethane (C 2H 6). A 3.337 µm CW ICL with an emitting wavenumber range of 2996.0–3001.5 cm –1 was used to simultaneously target two absorption lines, C 2H 6 at 2996.88 cm –1 and CH 4 at 2999.06 cm –1, respectively. The sensor performance was first evaluated for single-gas detection by only targeting the absorption line of one gas species. Allan deviations of 11.2 parts per billion in volume (ppbv) for CH 4 and 1.86 ppbv for Cmore » 2H 6 with an averaging time of 3.4 s were achieved for the detection of these two gases. Dual-gas detection was realized by using a long-term scan signal to target both CH 4 and C 2H 6 lines. The Allan deviations increased slightly to 17.4 ppbv for CH 4 and 2.4 ppbv for C 2H 6 with an averaging time of 4.6 s due to laser temperature and power drift caused by long-term wavelength scanning. Measurements for both indoor and outdoor concentration changes of CH 4 and C 2H 6 were conducted. As a result, the reported single ICL based dual-gas sensor system has the advantages of reduced size and cost compared to two separate sensor systems.« less

Mid-infrared dual-gas sensor for simultaneous detection of methane and ethane using a single continuous-wave interband cascade laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Weilin; Li, Chunguang; Zheng, Chuantao

A continuous-wave (CW) interband cascade laser (ICL) based mid-infrared sensor system was demonstrated for simultaneous detection of atmospheric methane (CH 4) and ethane (C 2H 6). A 3.337 µm CW ICL with an emitting wavenumber range of 2996.0–3001.5 cm –1 was used to simultaneously target two absorption lines, C 2H 6 at 2996.88 cm –1 and CH 4 at 2999.06 cm –1, respectively. The sensor performance was first evaluated for single-gas detection by only targeting the absorption line of one gas species. Allan deviations of 11.2 parts per billion in volume (ppbv) for CH 4 and 1.86 ppbv for Cmore » 2H 6 with an averaging time of 3.4 s were achieved for the detection of these two gases. Dual-gas detection was realized by using a long-term scan signal to target both CH 4 and C 2H 6 lines. The Allan deviations increased slightly to 17.4 ppbv for CH 4 and 2.4 ppbv for C 2H 6 with an averaging time of 4.6 s due to laser temperature and power drift caused by long-term wavelength scanning. Measurements for both indoor and outdoor concentration changes of CH 4 and C 2H 6 were conducted. As a result, the reported single ICL based dual-gas sensor system has the advantages of reduced size and cost compared to two separate sensor systems.« less

Effects of bubbles, cracks, and volcanic tephra on the spectral albedo of bare ice near the Transantarctic Mountains: Implications for sea glaciers on Snowball Earth

NASA Astrophysics Data System (ADS)

Dadic, Ruzica; Mullen, Peter C.; Schneebeli, Martin; Brandt, Richard E.; Warren, Stephen G.

2013-09-01

Spectral albedo was measured along a 6 km transect near the Allan Hills in East Antarctica. The transect traversed the sequence from new snow through old snow, firn, and white ice, to blue ice, showing a systematic progression of decreasing albedo at all wavelengths, as well as decreasing specific surface area (SSA) and increasing density. Broadband albedos under clear-sky range from 0.80 for snow to 0.57 for blue ice, and from 0.87 to 0.65 under cloud. Both air bubbles and cracks scatter sunlight; their contributions to SSA were determined by microcomputed tomography on core samples of the ice. Although albedo is governed primarily by the SSA (and secondarily by the shape) of bubbles or snow grains, albedo also correlates highly with porosity, which, as a proxy variable, would be easier for ice sheet models to predict than bubble sizes. Albedo parameterizations are therefore developed as a function of density for three broad wavelength bands commonly used in general circulation models: visible, near-infrared, and total solar. Relevance to Snowball Earth events derives from the likelihood that sublimation of equatorward-flowing sea glaciers during those events progressively exposed the same sequence of surface materials that we measured at Allan Hills, with our short 6 km transect representing a transect across many degrees of latitude on the Snowball ocean. At the equator of Snowball Earth, climate models predict thick ice, or thin ice, or open water, depending largely on their albedo parameterizations; our measured albedos appear to be within the range that favors ice hundreds of meters thick.

SESAME seeks cash to open its doors

NASA Astrophysics Data System (ADS)

Banks, Michael

2008-12-01

Researchers from the Middle East met in Jordan last month to celebrate progress towards the region's first synchrotron-radiation source, which is due to be ready for users by 2011. Known as SESAME, the facility is being built near the Al-Baqa' Applied University in Allan, about 30 km from the Jordanian capital Amman, and is designed to promote peaceful scientific co-operation between nations in the troubled region. However, the project still has to find 15m - a fifth of the total costs - in order to finish construction or SESAME risks being delayed beyond 2011.

Tilt-tuned etalon locking for tunable laser stabilization.

PubMed

Gibson, Bradley M; McCall, Benjamin J

2015-06-15

Locking to a fringe of a tilt-tuned etalon provides a simple, inexpensive method for stabilizing tunable lasers. Here, we describe the use of such a system to stabilize an external-cavity quantum cascade laser; the locked laser has an Allan deviation of approximately 1 MHz over a one-second integration period, and has a single-scan tuning range of approximately 0.4  cm(-1). The system is robust, with minimal alignment requirements and automated lock acquisition, and can be easily adapted to different wavelength regions or more stringent stability requirements with minor alterations.

On the Nature of Design

NASA Astrophysics Data System (ADS)

Valverde, Sergi; Solé, Ricard V.

At the attention of scientist, philosophers and layman alike. It was so extraordinary in fact that even today we are fascinated by it and by the no less uncommon people who got involved. The subject of this story was an amazing machine, more precisely an automaton. Known as the Turk, it was a mechanical chess player, made of wood and dressed in a Turkish-like costume (see Fig. 1). It played chess with Napoleon, inspired Charles Babbage and moved the great Edgar Allan Poe to write a critical essay about the nature of the automaton [1].

Rare Potassium-Bearing Mica in Allan Hills 84001: Additional Constraints on Carbonate Formation

NASA Technical Reports Server (NTRS)

Brearley, A. J.

1998-01-01

There have been presented several intriguing observations suggesting evidence of fossil life in martian orthopyroxenite ALH 84001. These exciting and controversial observations have stimulated extensive debate over the origin and history of ALH 84001, but many issues still remain unresolved. Among the most important is the question of the temperature at which the carbonates, which host the putative microfossils, formed. Oxygen- isotopic data, while showing that the carbonates are generally out of isotopic equilibria with the host rock, cannot constrain their temperature of formation. Both low- and high-temperature scenarios are plausible depending on whether carbonate growth occurred in an open or closed system. Petrographic arguments have generally been used to support a high-temperature origin but these appear to be suspect because they assume equilibrium between carbonate compositions that are not in contact. Some observations appear to be consistent with shock mobilization and growth from immiscible silicate-carbonate melts at high temperatures. Proponents of a low-temperature origin for the carbonates are hampered by the fact that there is currently no evidence of hydrous phases that would indicate low temperatures and the presence of a hydrous fluid during the formation of the carbonates. However, the absence of hydrous phases does not rule out carbonate formation at low temperatures, because the carbonate forming fluids may have been extremely CO2 rich, such that hydrous phases would not have been stabilized. In this study, I have carried out additional Transmission electron microscopy (TEM) studies of ALH-84001 and have found evidence of very rare phyllosilicates, which appear to be convincingly of pre-terrestrial origin. At present these observations are limited to one occurrence: further studies are in progress to determine if the phyllosilicates are more widespread.

Sustained maintenance of somatotopic information in brain regions recruited by tactile working memory.

PubMed

Katus, Tobias; Müller, Matthias M; Eimer, Martin

2015-01-28

To adaptively guide ongoing behavior, representations in working memory (WM) often have to be modified in line with changing task demands. We used event-related potentials (ERPs) to demonstrate that tactile WM representations are stored in modality-specific cortical regions, that the goal-directed modulation of these representations is mediated through hemispheric-specific activation of somatosensory areas, and that the rehearsal of somatotopic coordinates in memory is accomplished by modality-specific spatial attention mechanisms. Participants encoded two tactile sample stimuli presented simultaneously to the left and right hands, before visual retro-cues indicated which of these stimuli had to be retained to be matched with a subsequent test stimulus on the same hand. Retro-cues triggered a sustained tactile contralateral delay activity component with a scalp topography over somatosensory cortex contralateral to the cued hand. Early somatosensory ERP components to task-irrelevant probe stimuli (that were presented after the retro-cues) and to subsequent test stimuli were enhanced when these stimuli appeared at the currently memorized location relative to other locations on the cued hand, demonstrating that a precise focus of spatial attention was established during the selective maintenance of tactile events in WM. These effects were observed regardless of whether participants performed the matching task with uncrossed or crossed hands, indicating that WM representations in this task were based on somatotopic rather than allocentric spatial coordinates. In conclusion, spatial rehearsal in tactile WM operates within somatotopically organized sensory brain areas that have been recruited for information storage. Copyright © 2015 Katus et al.

Fermionology in the Kondo-Heisenberg model: the case of CeCoIn5

NASA Astrophysics Data System (ADS)

Zhong, Yin; Zhang, Lan; Lu, Han-Tao; Luo, Hong-Gang

2015-09-01

The Fermi surface of heavy electron systems plays a fundamental role in understanding their variety of puzzling phenomena, for example, quantum criticality, strange metal behavior, unconventional superconductivity and even enigmatic phases with yet unknown order parameters. The spectroscopy measurement of the typical heavy fermion superconductor CeCoIn5 has demonstrated multi-Fermi surface structure, which has not been studied in detail theoretically in a model system like the Kondo-Heisenberg model. In this work, we take a step toward such a theoretical model by revisiting the Kondo-Heisenberg model. It is found that the usual self-consistent calculation cannot reproduce the fermionology of the experimental observation of the system due to the sign binding between the hopping of the conduction electrons and the mean-field valence-bond order. To overcome such inconsistency, the mean-field valence-bond order is considered as a free/fitting parameter to correlate them with real-life experiments as performed in recent experiments [M.P. Allan, F. Massee, D.K. Morr, J. Van Dyke, A.W. Rost, A.P. Mackenzie, C. Petrovic, J.C. Davis, Nat. Phys. 9, 468 (2013); J. Van Dyke, F. Massee, M.P. Allan, J.C. Davis, C. Petrovic, D.K. Morr, Proc. Natl. Acad. Sci. 111, 11663 (2014)], which also explicitly reflects the intrinsic dispersion of local electrons observed in experimental measurements. Given the fermionology, the calculated effective mass enhancement, entropy, superfluid density and Knight shift are all in qualitative agreement with the experimental results of CeCoIn5, which confirms our assumption. Our result supports a d_{x^2 - y^2 }-wave pairing structure in the heavy fermion material CeCoIn5.

Noise characteristics in DORIS station positions time series derived from IGN-JPL, INASAN and CNES-CLS analysis centres

NASA Astrophysics Data System (ADS)

Khelifa, S.

2014-12-01

Using wavelet transform and Allan variance, we have analysed the solutions of weekly position residuals of 09 high latitude DORIS stations in STCD (STation Coordinate Difference) format provided from the three Analysis Centres : IGN-JPL (solution ign11wd01), INASAN (solution ina10wd01) and CNES-CLS (solution lca11wd02), in order to compare the spectral characteristics of their residual noise. The temporal correlations between the three solutions, two by two and station by station, for each component (North, East and Vertical) reveal a high correlation in the horizontal components (North and East). For the North component, the correlation average is about 0.88, 0.81 and 0.79 between, respectively, IGN-INA, IGN-LCA and INA-LCA solutions, then for the East component it is about 0.84, 0.82 and 0.76, respectively. However, the correlations for the Vertical component are moderate with an average of 0.64, 0.57 and 0.58 in, respectively, IGN-INA, IGN-LCA and INA-LCA solutions. After removing the trends and seasonal components from the analysed time series, the Allan variance analysis shows that the three solutions are dominated by a white noise in the all three components (North, East and Vertical). The wavelet transform analysis, using the VisuShrink method with soft thresholding, reveals that the noise level in the LCA solution is less important compared to IGN and INA solutions. Indeed, the standard deviation of the noise for the three components is in the range of 5-11, 5-12 and 4-9mm in the IGN, INA, and LCA solutions, respectively.

Comparison of 37 months global net radiation flux derived from PICARD-BOS over the same period observations of CERES and ARGO

NASA Astrophysics Data System (ADS)

Zhu, Ping; Wild, Martin

2016-04-01

The absolute level of the global net radiation flux (NRF) is fixed at the level of [0.5-1.0] Wm-2 based on the ocean heat content measurements [1]. The space derived global NRF is at the same order of magnitude than the ocean [2]. Considering the atmosphere has a negligible effects on the global NRF determination, the surface global NRF is consistent with the values determined from space [3]. Instead of studying the absolute level of the global NRF, we focus on the interannual variation of global net radiation flux, which were derived from the PICARD-BOS experiment and its comparison with values over the same period but obtained from the NASA-CERES system and inferred from the ocean heat content survey by ARGO network. [1] Allan, Richard P., Chunlei Liu, Norman G. Loeb, Matthew D. Palmer, Malcolm Roberts, Doug Smith, and Pier-Luigi Vidale (2014), Changes in global net radiative imbalance 1985-2012, Geophysical Research Letters, 41 (no.15), 5588-5597. [2] Loeb, Norman G., John M. Lyman, Gregory C. Johnson, Richard P. Allan, David R. Doelling, Takmeng Wong, Brian J. Soden, and Graeme L. Stephens (2012), Observed changes in top-of-the-atmosphere radiation and upper-ocean heating consistent within uncertainty, Nature Geoscience, 5 (no.2), 110-113. [3] Wild, Martin, Doris Folini, Maria Z. Hakuba, Christoph Schar, Sonia I. Seneviratne, Seiji Kato, David Rutan, Christof Ammann, Eric F. Wood, and Gert Konig-Langlo (2015), the energy balance over land and oceans: an assessment based on direct observations and CMIP5 climate models, Climate Dynamics, 44 (no.11-12), 3393-3429.

A comparison between different error modeling of MEMS applied to GPS/INS integrated systems.

PubMed

Quinchia, Alex G; Falco, Gianluca; Falletti, Emanuela; Dovis, Fabio; Ferrer, Carles

2013-07-24

Advances in the development of micro-electromechanical systems (MEMS) have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS) and the inertial navigation system (INS) integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs), stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV) and the power spectral density (PSD) techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR) filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade) presents error sources with short-term (high-frequency) and long-term (low-frequency) components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF) of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways.

KSC-02pd1480

NASA Image and Video Library

2002-10-08

KENNEDY SPACE CENTER, FLA. - Adam Kissiah (right), a retired NASA-KSC engineer, looks at a photo of Allan Dianic's daughter, who has benefited from a cochlear implant that Kissiah developed while at NASA. Dianic (left) is a software engineer with ENSCO. Kissiah received an exceptional category NASA Space Act Award for his 25-year-old technology breakthrough during a technology awards luncheon held at the KSC Visitor Complex Debus Center. The award included a monetary award and a certificate signed by the NASA Administrator. Space Act Awards provide official recognition and grant equitable monetary awards for inventions and scientific and technical contributions that have helped achieve NASA's aeronautical and space goals.

Equitable research: a bridge too far?

NASA Astrophysics Data System (ADS)

Walls, Leon

2017-06-01

This paper is written in response to Angela Chapman and Allan Feldman's research study, "Cultivation of science identity through authentic science in an urban high school". I utilize this forum piece to extend the call for "awakening a dialogue" that critically assesses the effectiveness of current K-12 science education research in addressing the needs of populations of color. I take the opportunity to first discuss elements of what an equitable research focus might look like. I finish by critiquing and ultimately commending the authors on the degree to which they succeed in demonstrating an equitable approach to the design and carrying out of their study.

Psychoanalysis and detective fiction: a tale of Freud and criminal storytelling.

PubMed

Yang, Amy

2010-01-01

Much has been written about Freud's influence on popular culture. This article addresses the influence of literature on Freud's psychoanalytical theory, specifically the role that modern detective fiction played in shaping Freudian theory. Edgar Allan Poe gave Freud the literary precedent; Sir Arthur Conan Doyle's creation Sherlock Holmes gave him the analytical model. In turn, the world of crime story-telling embedded Freudian theories in subsequent forms, spinning the tales of crime into a journey into the human mind. As these tales were popularized on the silver screen in the early 20th century, psychoanalytical ideas moved from the lecture halls into the cultural mainstream.

Terrestrial ages of Antarctic meteorites: Implications for concentration mechanisms

NASA Technical Reports Server (NTRS)

Schultz, L.

1986-01-01

Antarctic meteorites differ from meteorites fallen in other places in their mean terrestrial ages. Boeckl estimated the terrestrial half-life for the disintegration of stone meteorites by weathering under the climatic conditions of the Western United States to be about 3600 years. Antarctic meteorites, however, have terrestrial ages up to 70000 years, indicating larger weathering half-lives. The terrestrial ages of meteorites are determined by their concentration of cosmic-ray-produced radionuclides with suitable half-lives (C-14, Al-26, and Cl-36). These radionuclides have yielded reliable ages for the Antarctic meteorites. The distribution of terrestrial ages of Allan Hills and Yamato meteorites are examined.

La Vida Robot - High School Engineering Program Combats Engineering Brain Drain

ScienceCinema

Cameron, Allan; Lajvardi, Fredi

2018-05-04

Carl Hayden High School has built an impressive reputation with its robotics club. At a time when interest in science, math and engineering is declining, the Falcon Robotics club has young people fired up about engineering. Their program in underwater robots (MATE) and FIRST robotics is becoming a national model, not for building robots, but for building engineers. Teachers Fredi Lajvardi and Allan Cameron will present their story (How kids 'from the mean streets of Phoenix took on the best from M.I.T. in the national underwater bot championship' - Wired Magazine, April 2005) and how every student needs the opportunity to 'do real engineering.'

ARC-1984-AC85-0023-1-Edit

NASA Image and Video Library

1984-12-10

Medium Altitude Missions Branch: C-141 KAO Personnel, Mike Robinson, Mike Landis, Ed Hall, Tom Jones, John Graybeal, Louis Haughney, Brian Wright, Allan Meyer, Dick Gallant, Al Silva, Louis Russo, Hap Arnold, Randy Hobbs, Bill Laurie, Louis Foss, Sue Laurie, Tony Tieas, Tom Connors, Dave Brown, Alan Dunn, Don Oishi, Don Olson, Jim McClenahan, Wally Stahl, Sandy Mayville, Hank Hermosillo, Doug Ziebell, Ben Horita, Bill Hightower, Ron Sanchez, Terry Stoeffler, Lee Montz, Gene Moniz, John Brown, Bob America, Mike Craig, Kent Shiffer, Sandy Kogan, George Gull, Judy Pipher, Larry Helpher, Don MacKinnon, Jesse Bregmann, Jim Eilers, Nabil Hanania, Jim Cockrell, Keith Ackerman, Dave Walton, Lloyd Domeier, Pat Atchison

Unveiling the mechanisms of dressed-photon-phonon etching based on hierarchical surface roughness measure

NASA Astrophysics Data System (ADS)

Naruse, Makoto; Yatsui, Takashi; Nomura, Wataru; Kawazoe, Tadashi; Aida, Masaki; Ohtsu, Motoichi

2013-02-01

Dressed-photon-phonon (DPP) etching is a disruptive technology in planarizing material surfaces because it completely eliminates mechanical contact processes. However, adequate metrics for evaluating the surface roughness and the underlying physical mechanisms are still not well understood. Here, we propose a two-dimensional hierarchical surface roughness measure, inspired by the Allan variance, that represents the effectiveness of DPP etching while conserving the original two-dimensional surface topology. Also, we build a simple physical model of DPP etching that agrees well with the experimental observations, which clearly shows the involvement of the intrinsic hierarchical properties of dressed photons, or optical near-fields, in the surface processing.

A vibration-insensitive optical cavity and absolute determination of its ultrahigh stability.

PubMed

Zhao, Y N; Zhang, J; Stejskal, A; Liu, T; Elman, V; Lu, Z H; Wang, L J

2009-05-25

We use the three-cornered-hat method to evaluate the absolute frequency stabilities of three different ultrastable reference cavities, one of which has a vibration-insensitive design that does not even require vibration isolation. An Nd:YAG laser and a diode laser are implemented as light sources. We observe approximately 1 Hz beat note linewidths between all three cavities. The measurement demonstrates that the vibration-insensitive cavity has a good frequency stability over the entire measurement time from 100 ms to 200 s. An absolute, correlation-removed Allan deviation of 1.4 x 10(-15) at s of this cavity is obtained, giving a frequency uncertainty of only 0.44 Hz.

Low-noise correlation measurements based on software-defined-radio receivers and cooled microwave amplifiers.

PubMed

Nieminen, Teemu; Lähteenmäki, Pasi; Tan, Zhenbing; Cox, Daniel; Hakonen, Pertti J

2016-11-01

We present a microwave correlation measurement system based on two low-cost USB-connected software defined radio dongles modified to operate as coherent receivers by using a common local oscillator. Existing software is used to obtain I/Q samples from both dongles simultaneously at a software tunable frequency. To achieve low noise, we introduce an easy low-noise solution for cryogenic amplification at 600-900 MHz based on single discrete HEMT with 21 dB gain and 7 K noise temperature. In addition, we discuss the quantization effects in a digital correlation measurement and determination of optimal integration time by applying Allan deviation analysis.

La Vida Robot - High School Engineering Program Combats Engineering Brain Drain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cameron, Allan; Lajvardi, Fredi

Carl Hayden High School has built an impressive reputation with its robotics club. At a time when interest in science, math and engineering is declining, the Falcon Robotics club has young people fired up about engineering. Their program in underwater robots (MATE) and FIRST robotics is becoming a national model, not for building robots, but for building engineers. Teachers Fredi Lajvardi and Allan Cameron will present their story (How kids 'from the mean streets of Phoenix took on the best from M.I.T. in the national underwater bot championship' - Wired Magazine, April 2005) and how every student needs the opportunitymore » to 'do real engineering.'« less

Performance of the PARCS Testbed Cesium Fountain Frequency Standard

NASA Technical Reports Server (NTRS)

Enzer, Daphna G.; Klipstein, William M.

2004-01-01

A cesium fountain frequency standard has been developed as a ground testbed for the PARCS (Primary Atomic Reference Clock in Space) experiment, an experiment intended to fly on the International Space Station. We report on the performance of the fountain and describe some of the implementations motivated in large part by flight considerations, but of relevance for ground fountains. In particular, we report on a new technique for delivering cooling and trapping laser beams to the atom collection region, in which a given beam is recirculated three times effectively providing much more optical power than traditional configurations. Allan deviations down to 10 have been achieved with this method.

19. Photocopy of a photographca. 1923showing the Anyox Dam in ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

19. Photocopy of a photograph--ca. 1923--showing the Anyox Dam in British Columbia, Canada, just prior to completion of final arching. A sudden storm filled the reservoir and water began pouring over the uncompleted arch-ring; the dam was unhurt by the unexpected deluge and Eastwood used this photo as evidence of the great strength of his designs. Courtesy Mr. Charles Allan Whitney.20. DISTANT HELICOPTER VIEW TO SOUTHEAST UP LITTLE ROCK CREEK CANYON, WITH DAM AND RESERVOIR AT RIGHT CENTER. PALMDALE-LITTLEROCK DITCH, MARKED BY DENSE VEGETATION, CROSSES ROAD AT LOWER CENTER. - Little Rock Creek Dam, Little Rock Creek, Littlerock, Los Angeles County, CA

An improved offset generator developed for Allan deviation measurement of ultra stable frequency standards

NASA Technical Reports Server (NTRS)

Hamell, Robert L.; Kuhnle, Paul F.; Sydnor, Richard L.

1992-01-01

Measuring the performance of ultra stable frequency standards such as the Superconducting Cavity Maser Oscillator (SCMO) necessitates improvement of some test instrumentation. The frequency stability test equipment used at JPL includes a 1 Hz Offset Generator to generate a beat frequency between a pair of 100 MHz signals that are being compared. The noise floor of the measurement system using the current Offset Generator is adequate to characterize stability of hydrogen masers, but it is not adequate for the SCMO. A new Offset Generator with improved stability was designed and tested at JPL. With this Offset Generator and a new Zero Crossing Detector, recently developed at JPL, the measurement flow was reduced by a factor of 5.5 at 1 second tau, 3.0 at 1000 seconds, and 9.4 at 10,000 seconds, compared against the previous design. In addition to the new circuit designs of the Offset Generator and Zero Crossing Detector, tighter control of the measurement equipment environment was required to achieve this improvement. The design of this new Offset Generator are described, along with details of the environment control methods used.

Accumulation mechanisms and the weathering of Antarctic equilibrated ordinary chondrites

NASA Astrophysics Data System (ADS)

Benoit, P. H.; Sears, D. W. G.

1999-06-01

Induced thermoluminescence (TL) is used to quantitatively evaluate the degree of weathering of meteorites found in Antarctica. We find a weak correlation between TL sensitivity and descriptions of weathering in hand specimens, the highly weathered meteorites having lower TL sensitivity than unweathered meteorites. Analysis of samples taken throughout large meteorites shows that the heterogeneity in TL sensitivity within meteorite finds is not large relative to the range exhibited by different weathered meteorites. The TL sensitivity values can be restored by minimal acid washing, suggesting the lower TL sensitivities of weathered meteorites reflects thin weathering rims on mineral grains or coating of these grains by iron oxides produced by hydration and oxidation of metal and sulfides. Small meteorites may tend to be more highly weathered than large meteorites at the Allan Hills ice fields. We find that meteorite fragments >150 g may take up to 300,000 years to reach the highest degrees of weathering, while meteorites <150 g require <40,000 years. However, at other fields, local environmental conditions and variability in terrestrial history are more important in determining weathering than size alone. Weathering correlates poorly with surface exposure duration, presumably because weathering occurs primarily during interglacial periods. The Allan Hills locality has served as a fairly stable surface over the last 100,000 years or so and has efficiently preserved both small and large meteorites. Meteorites from Lewis Cliff, however, have experienced extensive weathering, probably because of increased surface melt water from nearby outcrops. Meteorites from the Elephant Moraine locality tend to exhibit only minor degrees of weathering, but small meteorites are less weathered than large meteorites, which we suggest is due to the loss of small meteorites by aeolian transport.

Mid-infrared dual-gas sensor for simultaneous detection of methane and ethane using a single continuous-wave interband cascade laser.

PubMed

Ye, Weilin; Li, Chunguang; Zheng, Chuantao; Sanchez, Nancy P; Gluszek, Aleksander K; Hudzikowski, Arkadiusz J; Dong, Lei; Griffin, Robert J; Tittel, Frank K

2016-07-25

A continuous-wave (CW) interband cascade laser (ICL) based mid-infrared sensor system was demonstrated for simultaneous detection of atmospheric methane (CH₄) and ethane (C₂H₆). A 3.337 µm CW ICL with an emitting wavenumber range of 2996.0-3001.5 cm^-1 was used to simultaneously target two absorption lines, C₂H₆ at 2996.88 cm^-1 and CH₄ at 2999.06 cm^-1, respectively. The sensor performance was first evaluated for single-gas detection by only targeting the absorption line of one gas species. Allan deviations of 11.2 parts per billion in volume (ppbv) for CH₄ and 1.86 ppbv for C₂H₆ with an averaging time of 3.4 s were achieved for the detection of these two gases. Dual-gas detection was realized by using a long-term scan signal to target both CH₄ and C₂H₆ lines. The Allan deviations increased slightly to 17.4 ppbv for CH₄ and 2.4 ppbv for C₂H₆ with an averaging time of 4.6 s due to laser temperature and power drift caused by long-term wavelength scanning. Measurements for both indoor and outdoor concentration changes of CH₄ and C₂H₆ were conducted. The reported single ICL based dual-gas sensor system has the advantages of reduced size and cost compared to two separate sensor systems.

Structure of a forested urban park: implications for strategic management.

PubMed

Millward, Andrew A; Sabir, Senna

2010-11-01

Informed management of urban parks can provide optimal conditions for tree establishment and growth and thus maximize the ecological and aesthetic benefits that trees provide. This study assesses the structure, and its implications for function, of the urban forest in Allan Gardens, a 6.1 ha downtown park in the City of Toronto, Canada, using the Street Tree Resource Analysis Tool for Urban Forest Managers (STRATUM). Our goal is to present a framework for collection and analysis of baseline data that can inform a management strategy that would serve to protect and enhance this significant natural asset. We found that Allan Garden's tree population, while species rich (43), is dominated by maple (Acer spp.) (48% of all park trees), making it reliant on very few species for the majority of its ecological and aesthetic benefits and raising disease and pest-related concerns. Age profiles (using size as a proxy) showed a dominance of older trees with an inadequate number of individuals in the young to early middle age cohort necessary for short- to medium-term replacement. Because leaf area represents the single-most important contributor to urban tree benefits modelling, we calculated it separately for every park tree, using hemispheric photography, to document current canopy condition. These empirical measurements were lower than estimates produced by STRATUM, especially when trees were in decline and lacked full canopies, highlighting the importance of individual tree condition in determining leaf area and hence overall forest benefits. Stewardship of natural spaces within cities demands access to accurate and timely resource-specific data. Our work provides an uncomplicated approach to the acquisition and interpretation of these data in the context of a forested urban park. Copyright 2010 Elsevier Ltd. All rights reserved.

Fiber optic reference frequency distribution to remote beam waveguide antennas

NASA Technical Reports Server (NTRS)

Calhoun, Malcolm; Kuhnle, Paul; Law, Julius

1995-01-01

In the NASA/JPL Deep Space Network (DSN), radio science experiments (probing outer planet atmospheres, rings, gravitational waves, etc.) and very long-base interferometry (VLBI) require ultra-stable, low phase noise reference frequency signals at the user locations. Typical locations for radio science/VLBI exciters and down-converters are the cone areas of the 34 m high efficiency antennas or the 70 m antennas, located several hundred meters from the reference frequency standards. Over the past three years, fiber optic distribution links have replaced coaxial cable distribution for reference frequencies to these antenna sites. Optical fibers are the preferred medium for distribution because of their low attenuation, immunity to EMI/IWI, and temperature stability. A new network of Beam Waveguide (BWG) antennas presently under construction in the DSN requires hydrogen maser stability at tens of kilometers distance from the frequency standards central location. The topic of this paper is the design and implementation of an optical fiber distribution link which provides ultra-stable reference frequencies to users at a remote BWG antenna. The temperature profile from the earth's surface to a depth of six feet over a time period of six months was used to optimize the placement of the fiber optic cables. In-situ evaluation of the fiber optic link performance indicates Allan deviation on the order of parts in 10(exp -15) at 1000 and 10,000 seconds averaging time; thus, the link stability degradation due to environmental conditions still preserves hydrogen maser stability at the user locations. This paper reports on the implementation of optical fibers and electro-optic devices for distributing very stable, low phase noise reference signals to remote BWG antenna locations. Allan deviation and phase noise test results for a 16 km fiber optic distribution link are presented in the paper.

A Comparison between Different Error Modeling of MEMS Applied to GPS/INS Integrated Systems

PubMed Central

Quinchia, Alex G.; Falco, Gianluca; Falletti, Emanuela; Dovis, Fabio; Ferrer, Carles

2013-01-01

Advances in the development of micro-electromechanical systems (MEMS) have made possible the fabrication of cheap and small dimension accelerometers and gyroscopes, which are being used in many applications where the global positioning system (GPS) and the inertial navigation system (INS) integration is carried out, i.e., identifying track defects, terrestrial and pedestrian navigation, unmanned aerial vehicles (UAVs), stabilization of many platforms, etc. Although these MEMS sensors are low-cost, they present different errors, which degrade the accuracy of the navigation systems in a short period of time. Therefore, a suitable modeling of these errors is necessary in order to minimize them and, consequently, improve the system performance. In this work, the most used techniques currently to analyze the stochastic errors that affect these sensors are shown and compared: we examine in detail the autocorrelation, the Allan variance (AV) and the power spectral density (PSD) techniques. Subsequently, an analysis and modeling of the inertial sensors, which combines autoregressive (AR) filters and wavelet de-noising, is also achieved. Since a low-cost INS (MEMS grade) presents error sources with short-term (high-frequency) and long-term (low-frequency) components, we introduce a method that compensates for these error terms by doing a complete analysis of Allan variance, wavelet de-nosing and the selection of the level of decomposition for a suitable combination between these techniques. Eventually, in order to assess the stochastic models obtained with these techniques, the Extended Kalman Filter (EKF) of a loosely-coupled GPS/INS integration strategy is augmented with different states. Results show a comparison between the proposed method and the traditional sensor error models under GPS signal blockages using real data collected in urban roadways. PMID:23887084

Fiber optic reference frequency distribution to remote beam waveguide antennas

NASA Astrophysics Data System (ADS)

Calhoun, Malcolm; Kuhnle, Paul; Law, Julius

1995-05-01

In the NASA/JPL Deep Space Network (DSN), radio science experiments (probing outer planet atmospheres, rings, gravitational waves, etc.) and very long-base interferometry (VLBI) require ultra-stable, low phase noise reference frequency signals at the user locations. Typical locations for radio science/VLBI exciters and down-converters are the cone areas of the 34 m high efficiency antennas or the 70 m antennas, located several hundred meters from the reference frequency standards. Over the past three years, fiber optic distribution links have replaced coaxial cable distribution for reference frequencies to these antenna sites. Optical fibers are the preferred medium for distribution because of their low attenuation, immunity to EMI/IWI, and temperature stability. A new network of Beam Waveguide (BWG) antennas presently under construction in the DSN requires hydrogen maser stability at tens of kilometers distance from the frequency standards central location. The topic of this paper is the design and implementation of an optical fiber distribution link which provides ultra-stable reference frequencies to users at a remote BWG antenna. The temperature profile from the earth's surface to a depth of six feet over a time period of six months was used to optimize the placement of the fiber optic cables. In-situ evaluation of the fiber optic link performance indicates Allan deviation on the order of parts in 10(exp -15) at 1000 and 10,000 seconds averaging time; thus, the link stability degradation due to environmental conditions still preserves hydrogen maser stability at the user locations. This paper reports on the implementation of optical fibers and electro-optic devices for distributing very stable, low phase noise reference signals to remote BWG antenna locations. Allan deviation and phase noise test results for a 16 km fiber optic distribution link are presented in the paper.

Antarctic Meteorite Location and Mapping Project (AMLAMP): Antarctic meteorite location map series explanatory text and user's guide to AMLAMP data

NASA Technical Reports Server (NTRS)

Schutt, J.; Fessler, B.; Cassidy, W. A.

1993-01-01

This technical report is an update to LPI Technical Report 89-02, which contained data and information that was current to May 1987. Since that time approximately 4000 new meteorites have been collected, mapped, and characterized, mainly from the numerous ice fields in the Allan Hills-David Glacier region, from the Pecora Escarpment and Moulton Escarpment in the Thiel Mountains-Patuxent region, the Wisconsin Range region, and from the Beardmore region. Meteorite location maps for ice fields from these regions have been produced and are available. This report includes explanatory texts for the maps of new areas and provides information on updates of maps of the areas covered in LPI Technical Report 89-02. Sketch maps and description of locales that have been searched and have yielded single or few meteorites are also included. The meteorite listings for all the ice fields have been updated to include any classification changes and new meteorites recovered from ice fields in the Allan Hills-David Glacier region since 1987. The text has been reorganized and minor errors in the original report have been corrected. Computing capabilities have improved immensely since the early days of this project. Current software and hardware allow easy access to data over computer networks. With various commercial software packages, the data can be used many different ways, including database creation, statistics, and mapping. The databases, explanatory texts, and the plotter files used to produce the meteorite location maps are available through a computer network. Information on how to access AMLAMP data, its formats, and ways it can be used are given in the User's Guide to AMLAMP Data section. Meteorite location maps and thematic maps may be ordered from the Lunar and Planetary Institute. Ordering information is given in Appendix A.

Cryogenic sapphire oscillator using a low-vibration design pulse-tube cryocooler: first results.

PubMed

Hartnett, John; Nand, Nitin; Wang, Chao; Floch, Jean-Michel

2010-05-01

A cryogenic sapphire oscillator (CSO) has been implemented at 11.2 GHz using a low-vibration design pulsetube cryocooler. Compared with a state-of-the-art liquid helium cooled CSO in the same laboratory, the square root Allan variance of their combined fractional frequency instability is sigma(y) = 1.4 x 10(-15)tau(-1/2) for integration times 1 < tau < 10 s, dominated by white frequency noise. The minimum sigmay = 5.3 x 10(-16) for the two oscillators was reached at tau = 20 s. Assuming equal contributions from both CSOs, the single oscillator phase noise S(phi) approximately -96 dB x rad(2)/Hz at 1 Hz set from the carrier.

Data Element Dictionary of Five Federal Agencies’ Systems for Processing of Technical Report Literature

DTIC Science & Technology

1983-01-01

ELZRNT: kepozt CI&MlflcatiOm SOU* cft AGENCY: DYUC OSI: flaadatory C, x f cato itadlcto. the degree of protectloo rq~ird age Acatof t alo di Řs0 14...03 ELS9 704T £33 &AC12COMPATISLA UNIOZUGS. ONE fiulflckiO6:. ’LITL AhL 0133 iViOAJS905Z ൕ.X2 A&W (3KW&95.’) MAR iQ .4322.18.1u -IEI 39UAS AML Mk...WOhiI oilo xis 11 ALLA.n iN 30353. Sot$ !IUPOAAI DATA 11 DOW=I3on AMl £MCLObSD hI~dh 66"AS 9BACASX K34 . *NTNUvAL Tag: $If

Coherent population trapping with a controlled dissipation: applications in optical metrology

NASA Astrophysics Data System (ADS)

Nicolas, L.; Delord, T.; Jamonneau, P.; Coto, R.; Maze, J.; Jacques, V.; Hétet, G.

2018-03-01

We analyze the properties of a pulsed coherent population trapping protocol that uses a controlled decay from the excited state in a Λ-level scheme. We study this problem analytically and numerically and find regimes where narrow transmission, absorption, or fluorescence spectral lines occur. We then look for optimal frequency measurements using these spectral features by computing the Allan deviation in the presence of ground state decoherence and show that the protocol is on a par with Ramsey-CPT. We discuss possible implementations with ensembles of alkali atoms and single ions and demonstrate that typical pulsed-CPT experiments that are realized on femto-second timescales can be implemented on micro-seconds timescales using this scheme.

Field experiments for student learning – what I learnt in my first weeks in Sweden two decades ago

NASA Astrophysics Data System (ADS)

Seibert, Jan

2015-04-01

Field experiments can be extremely valuable for obtaining a good understanding of hydrological processes. In this poster I revisit a field course held by Allan Rodhe when I came to Sweden two decades ago, and ask myself, with a long-term perspective, what I learnt during this course. Some of the experiments are described in more detail such as the estimation of hydraulic conductivities based on groundwater salt dilution and an experiment to demonstrate the difference between flood-wave velocity and water particle velocity. Furthermore, some general thoughts on challenges to generate a good learning environment in the field are given based on my personal experiences as a student, an assistant and a teacher.

Genetic disorders of thyroid metabolism and brain development

PubMed Central

Kurian, Manju A; Jungbluth, Heinz

2014-01-01

Normal thyroid metabolism is essential for human development, including the formation and functioning of the central and peripheral nervous system. Disorders of thyroid metabolism are increasingly recognized within the spectrum of paediatric neurological disorders. Both hypothyroid and hyperthyroid disease states (resulting from genetic and acquired aetiologies) can lead to characteristic neurological syndromes, with cognitive delay, extrapyramidal movement disorders, neuropsychiatric symptoms, and neuromuscular manifestations. In this review, the neurological manifestations of genetic disorders of thyroid metabolism are outlined, with particular focus on Allan-Herndon-Dudley syndrome and benign hereditary chorea. We report in detail the clinical features, major neurological and neuropsychiatric manifestations, molecular genetic findings, disease mechanisms, and therapeutic strategies for these emerging genetic ‘brain-thyroid’ disorders. PMID:24665922

Laser frequency stabilization using a commercial wavelength meter

NASA Astrophysics Data System (ADS)

Couturier, Luc; Nosske, Ingo; Hu, Fachao; Tan, Canzhu; Qiao, Chang; Jiang, Y. H.; Chen, Peng; Weidemüller, Matthias

2018-04-01

We present the characterization of a laser frequency stabilization scheme using a state-of-the-art wavelength meter based on solid Fizeau interferometers. For a frequency-doubled Ti-sapphire laser operated at 461 nm, an absolute Allan deviation below 10-9 with a standard deviation of 1 MHz over 10 h is achieved. Using this laser for cooling and trapping of strontium atoms, the wavemeter scheme provides excellent stability in single-channel operation. Multi-channel operation with a multimode fiber switch results in fluctuations of the atomic fluorescence correlated to residual frequency excursions of the laser. The wavemeter-based frequency stabilization scheme can be applied to a wide range of atoms and molecules for laser spectroscopy, cooling, and trapping.

20. San FranciscoOakland Bay Bridge contract recipients, April 28, 1933, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. San Francisco-Oakland Bay Bridge contract recipients, April 28, 1933, photographer unknown. Standing, left to right: Edward J. Schneider, Columbia Steel Corporation; C.C. Horton, Healy-Tibbitts Construction Company; Henry J. Kaiser, Bridge Builders, Inc.; Albert Huber, Clinton Construction Company; Allan McDonald, Transbay Construction Company; C.C. Carleton, Chief, Division of Contracts and Rights of Way, California Department of Public Works. Seated, left to right: Henry J. Brunnier, Consulting Engineer, Member of Consulting Board, San Francisco-Oakland Bay Bridge; Charles E. Andrew, Bridge Engineer, San Francisco-Oakland Bay Bridge; Earl Lee Kelly, Director, California Department of Public Works; Harrison S. Robinson, President, Financial ... - Salt River Bridge, Spanning Salt River at Dillon Road, Ferndale, Humboldt County, CA

Frequency stabilization of an Er-doped fiber laser with a collinear 2f-to-3f self-referencing interferometer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hitachi, K., E-mail: hitachi.kenichi@lab.ntt.co.jp; Ishizawa, A.; Mashiko, H.

2015-06-08

We report the stabilization of the carrier-envelope offset (CEO) frequency of an Er-doped fiber laser with a collinear 2f-to-3f self-referencing interferometer. The interferometer is implemented by a dual-pitch periodically poled lithium niobate ridge waveguide with two different quasi-phase matching pitch sizes. We obtain a 52-dB signal-to-noise ratio in the 100-kHz resolution bandwidth of a heterodyne beat signal, which is sufficient for frequency stabilization. We also demonstrate that the collinear geometry is robust against environmental perturbation by comparing in-loop and out-of-loop Allan deviations when the in-loop CEO frequency is stabilized with a phase-locked loop circuit.

An ancient core dynamo in asteroid Vesta.

PubMed

Fu, Roger R; Weiss, Benjamin P; Shuster, David L; Gattacceca, Jérôme; Grove, Timothy L; Suavet, Clément; Lima, Eduardo A; Li, Luyao; Kuan, Aaron T

2012-10-12

The asteroid Vesta is the smallest known planetary body that has experienced large-scale igneous differentiation. However, it has been previously uncertain whether Vesta and similarly sized planetesimals formed advecting metallic cores and dynamo magnetic fields. Here we show that remanent magnetization in the eucrite meteorite Allan Hills A81001 formed during cooling on Vesta 3.69 billion years ago in a surface magnetic field of at least 2 microteslas. This field most likely originated from crustal remanence produced by an earlier dynamo, suggesting that Vesta formed an advecting liquid metallic core. Furthermore, the inferred present-day crustal fields can account for the lack of solar wind ion-generated space weathering effects on Vesta.

Substorm Related ULF waves Observed in the Magnetosphere by BD-IES and Van Allan Probes

NASA Astrophysics Data System (ADS)

Zong, Q.

2017-12-01

By using the data return from the BD-IES instrument onboard an inclined (55°) geosynchronous orbit (IGSO) satellite together with geo-transfer orbit (GTO) Van Allen Probe A&B satellite, we analysis a substorm related ULF waves occurred on Feb 5, 2016 in the dawnside of the magnetosphere. Immediately after the substorm injection followed by energetic electron drift echoes, the electron flux was clearly and strongly varying on the ULF wave time scale. It is found that both toroidal and poloidal mode ULF waves with a period of 320 s. During the substorm injection, the IES onboard IGSO is outbound while both Van Allen Probe A&B satellites are inbound. This configuration of multiple satellite trajectories provides an unique opportunity to investigate substorm related ULF waves. When substorm injections are observed simultaneously with multiple spacecraft, they help elucidate potential mechanisms for particle transport and energization, a topic of great importance for understanding and modeling the magnetosphere. Two possible scenaria on ULF wave triggering are discussed: fast-mode compressional waves -driven field line resonance and ULF wave growth through drift resonance.

Edgar Allan Poe: a case description of the Marfan syndrome in an obscure short story.

PubMed

Battle, Robert W

2011-07-01

In the obscure short story “A Tale of the Ragged Mountains,” Edgar Allen Poe meticulously described a character with features remarkably consistent with the Marfan syndrome. This description appeared in fiction >50 years before the celebrated index description in the published medical research by Professor Antoine Marfan in Paris in 1896.

DSP Synthesis Algorithm for Generating Florida Scrub Jay Calls

NASA Technical Reports Server (NTRS)

Lane, John; Pittman, Tyler

2017-01-01

A prototype digital signal processing (DSP) algorithm has been developed to approximate Florida scrub jay calls. The Florida scrub jay (Aphelocoma coerulescens), believed to have been in existence for 2 million years, living only in Florida, has a complicated social system that is evident by examining the spectrograms of its calls. Audio data was acquired at the Helen and Allan Cruickshank Sanctuary, Rockledge, Florida during the 2016 mating season using three digital recorders sampling at 44.1 kHz. The synthesis algorithm is a first step at developing a robust identification and call analysis algorithm. Since the Florida scrub jay is severely threatened by loss of habitat, it is important to develop effective methods to monitor their threatened population using autonomous means.

METEORITE - ASTRONOMY

NASA Image and Video Library

1985-08-28

S85-39565 (For release August 1996) --- According to scientists, this 4.5 billion year old rock, labeled meteorite ALH84001, is believed to have once been a part of Mars and to contain fossil evidence that primitive life may have existed on Mars more than 3.6 billion years ago. The rock is a portion of a meteorite that was dislodged from Mars by a huge impact about 16 million years ago and that fell to Earth in Antarctica 13,000 years ago. The meteorite was found in Allan Hills ice field, Antarctica, by an annual expedition of the National Science Foundation?s Antarctic Meteorite Program in 1984. It is preserved for study at the Johnson Space Center?s (JSC) Meteorite Processing Laboratory in Houston, Texas.

Laser frequency-offset locking based on the frequency modulation spectroscopy with higher harmonic detection

NASA Astrophysics Data System (ADS)

Wang, Anqi; Meng, Zhixin; Feng, Yanying

2017-10-01

We design a fiber electro-optic modulator (FEOM)-based laser frequency-offset locking system using frequency modulation spectroscopy (FMS) with the 3F modulation. The modulation signal and the frequency-offset control signal are simultaneously loaded on the FEOM by a mixer in order to suppress the frequency and power jitter caused by internal modulation on the current or piezoelectric ceramic transducer (PZT). It is expected to accomplish a fast locking, a widely tunable frequency-offset, a sensitive and rapid detection of narrow spectral features with the 3F modulation. The laser frequency fluctuation is limited to +/-1MHz and its overlapping Allan deviation is around 10-12 in twenty minutes, which successfully meets the requirements of the cold atom interferometer.

Chemical compositional study of 35 iron meteorites and its application in taxonomy

NASA Technical Reports Server (NTRS)

Wang, D.; Malvin, D. J.; Wasson, J. T.

1985-01-01

Structural and compositional data are reported as a guide to the classification of 35 iron meteorites. The Xinjiang iron meteorite, previously classified as III AB, is reclassified as III E on the basis of its lower Ga/Ni and Ge/Ni ratios, its wider, swollen kamacite bands, and the ubiquitous presence of haxonite, (Fe,Ni)22C. The Dongling (III CD) appears not to be a new meteorite, but to be paired with the Nantan. Four Antarctic iron meteorites, IAB Allan Hills A77250, A77263, A77289, and A77290, are classified as a paired meteorite because of their similarities in structure and in concentrations of various elements. It is shown that Cu shares certain properties with Ga and Ge, which makes them excellent taxonomic parameters.

Implementation and characterization of a stable optical frequency distribution system.

PubMed

Bernhardt, Birgitta; Hänsch, Theodor W; Holzwarth, Ronald

2009-09-14

An optical frequency distribution system has been developed that continuously delivers a stable optical frequency of 268 THz (corresponding to a wavelength of 1118 nm) to different experiments in our institute. For that purpose, a continuous wave (cw) fiber laser has been stabilized onto a frequency comb and distributed across the building by the use of a fiber network. While the light propagates through the fiber, acoustic and thermal effects counteract against the stability and accuracy of the system. However, by employing proper stabilization methods a stability of 2 x 10(-13) tau(-1/2) is achieved, limited by the available radio frequency (RF) reference. Furthermore, the issue of counter-dependant results of the Allan deviation was examined during the data evaluation.

Shattered illusions: the effect of explicit memory mediation on an indirect memory test.

PubMed

Gooding, P A; Mayes, A R; Meudell, P R

1999-05-01

Four experiments were conducted to explore the possible involvement of explicit memory in an indirect memory test in which white noise accompanying old sentences was judged to be quieter than white noise accompanying new sentences (Jacoby, Allan, Collins & Larwill, 1988). Experiment 1 established that this effect lasted up to 1 week. Experiment 2 found that a group of amnesic patients showed a noise effect that was marginally above chance and not significantly less that that of their matched controls after a delay of one day. Effect of time pressure at test (Experiment 3) and divided attention at study (Experiment 4) suggested that the memory processes mediating the noise effect were not automatic, although the possibility that the processes involve enhanced fluency is also discussed.

International nuclear safety concerns. Hearing before the Subcommittee on Energy, Nuclear Proliferation, and Government Processes of the Committee on Governmental Affairs, United States Senate, Ninety-Ninth Congress, Second Session, May 8, 1986

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1986-01-01

Allan I. Mendelowitz of the General Accounting Office (GAO) and James R. Shea of the Nuclear Regulatory Commission were the principal witnesses at a hearing on international concerns about reactor safety. The hearing focused on the Soviet accident at Chernobyl as a demonstration that safety matters are a legitimate area of international concern. Among the issues under discussion were safety standards and inspection procedures of the International Atomic Energy Agency (IAEA). Estimates developed by the GAO show that developing countries, which lack a strong technical base or nuclear background to handle emergencies, will have half the reactors in the worldmore » by the year 2000. Mendelowitz and Shea, together with supporting testimony from others in their agencies described international efforts to improve safeguards.« less

Clay-mineraloid weathering products in Antarctic meteorites

NASA Technical Reports Server (NTRS)

Gooding, James L.

1986-01-01

The production of clay mineraloids (CMs) in the weathering of stony meteorites recovered in the Allan Hills and Elephant Moraine areas of Antarctica is investigated, applying electron microbeam analysis, pyrolysis/mass spectroscopy, X-ray diffractometry, and differential scanning calorimetry to whole-rock chips from two eucrites, two diogenites, and an H5 chondrite. The data are presented in tables, graphs, and photomicrographs and characterized in detail. Massive to incipient-vermicular CM formations with smectitelike or micalike compositions and indications of poor crystallization are observed and attributed to hydrocryogenic diagenesis (with little or no liquid water) on time scales of 10-1000 kyr. The need to take the compositional effects of weathering into account before attempting to reconstruct the preterrestrial histories of meteorites is stressed.

Eddy Covariance measurements of stable isotopes (δD and δ18O) in water vapor

NASA Astrophysics Data System (ADS)

Braden-Behrens, Jelka; Knohl, Alexander

2017-04-01

Stable isotopes are a promising tool to enhance our understanding of ecosystem gas exchanges. Studying 18O and 2H in water vapour (H2Ov) can e.g. help partitioning evapotranspiration into its components. With recent developments in laser spectroscopy direct Eddy Covariance (EC) measurements for investigating fluxes of stable isotopologues became feasible. So far very few case studies have applied the EC method to measure stable isotopes in water vapor. We continuously measure fluxes of water vapor isotopologues with the EC method in a managed beech forest in Thuringia, Germany, since autumn 2015 using the following setup: An off-axis integrated cavity output water vapor isotope analyzer (WVIA, Los Gatos Research. Inc, USA) measures the water vapour concentration and its isotopic composition (δD and δ18O). The instrument, that was optimized for high flow rates (app. 4slpm) to generate high frequency (2Hz) measurements, showed sufficient precision with Allan Deviations of app. 0.12 ‰ for δD and 0.06 ‰ for δ18O for averaging periods of 100s. The instrument was calibrated hourly using a high-flow optimized version of the water vapor isotope standard source (WVISS, Los Gatos Research. Inc, USA) that provides water vapor with known isotopic composition for a large range of different concentrations. Our calibration scheme includes a near continuous concentration range calibration instead of a simple 2 or 3-point calibration to face the analyzers strong concentration dependency within a range of app. 6 000 to 16 000 ppm in winter and app. 8 000 to 23 000 ppm in summer. In the used setup, the high-flow and high-frequency optimized water vapor isotope analyzer (WVIA) showed suitable characteristics (Allan deviation and spectral energy distribution) to perform Eddy covariance measurements of stable isotopes in H2Ov. Thus, this novel instrument for EC measurements of water vapor isotopologues provides a new opportunity for studying the hydrological cycle in long

Terrestrial ages of ordinary chondrites from the lewis cliff stranding area, East Antarctica

NASA Astrophysics Data System (ADS)

Welten, K. C.; Lindner, L.; Alderliesten, C.; van der Borg, K.

1999-07-01

We determined terrestrial ages of ordinary chondrites from the Lewis Cliff stranding area, East Antarctica, on the basis of the concentrations of cosmogenic 10Be (t1/2 = 1.51 Ma), 26Al (t1/2 = 0.705 Ma) and 36Cl (t1/2 = 0.301 Ma). After an initial 26Al -ray survey of 91 meteorites suggested that many have terrestrial ages larger than 0.1 Ma, we selected 62 meteorites for 10Be and 26Al measurements by accelerator mass spectrometry (AMS) and measured 36Cl in twelve of those. Low terrestrial ages (<0.1 Ma) were found for about 60% of the meteorites, whereas all others have ages between 0.1 and 0.5 Ma, except for one exceptional age of >2 Ma (Welten et al., 1997). Our major conclusions are: (1) The Lewis Cliff H-chondrites show similar ages as those from the Allan Hills Ice-fields, but the L-chondrites are about a factor of two younger than those from Allan Hills, which indicates that Lewis Cliff is a younger stranding area. (2) The terrestrial age distributions at different parts of the Lewis Cliff stranding area generally agree with simple meteorite concentration models, although differences in weathering rate may also play a role. (3) We confirm that meteorites with natural thermoluminescence (TL) levels >80 krad are associated with low terrestrial ages (Benoit et al., 1992), but conclude that natural TL levels <80 krad can not be used to calculate the terrestrial age of a meteorite. Natural TL levels do seem useful to estimate relative terrestrial ages of large groups of meteorites and to determine differences in surface exposure age of paired meteorite fragments. (4) Of the 62 meteorites measured with AMS, 31 were assigned to eleven different pairing groups, mainly on the basis of their cosmogenic nuclide record. The meteorites are estimated to represent between 42 and 52 distinct falls.

Using the Deep Space Atomic Clock for Navigation and Science.

PubMed

Ely, Todd A; Burt, Eric A; Prestage, John D; Seubert, Jill M; Tjoelker, Robert L

2018-06-01

Routine use of one-way radiometric tracking for deep space navigation and radio science is not possible today because spacecraft frequency and time references that use state-of-the-art ultrastable oscillators introduce errors from their intrinsic drift and instability on timescales past 100 s. The Deep Space Atomic Clock (DSAC), currently under development as a NASA Technology Demonstration Mission, is an advanced prototype of a space-flight suitable, mercury-ion atomic clock that can provide an unprecedented frequency and time stability in a space-qualified clock. Indeed, the ground-based results of the DSAC space demonstration unit have already achieved an Allan deviation of at one day; space performance on this order will enable the use of one-way radiometric signals for deep space navigation and radio science.

Sherlock Holmes: scientific detective.

PubMed

Snyder, Laura J

2004-09-01

Sherlock Holmes was intended by his creator, Arthur Conan Doyle, to be a 'scientific detective'. Conan Doyle criticized his predecessor Edgar Allan Poe for giving his creation - Inspector Dupin - only the 'illusion' of scientific method. Conan Doyle believed that he had succeeded where Poe had failed; thus, he has Watson remark that Holmes has 'brought detection as near an exact science as it will ever be brought into the world.' By examining Holmes' methods, it becomes clear that Conan Doyle modelled them on certain images of science that were popular in mid- to late-19th century Britain. Contrary to a common view, it is also evident that rather than being responsible for the invention of forensic science, the creation of Holmes was influenced by the early development of it.

The Antarctic environment and its effect upon the total carbon and sulfur abundances in recovered meteorites

NASA Technical Reports Server (NTRS)

Gibson, E. K., Jr.; Andrawes, F. F.

1980-01-01

Total carbon and sulfur abundances have been measured for 25 meteorites recovered from the Allan Hills area of Antarctica. The majority (greater than 67%) of the meteorites analyzed do not contain enriched carbon abundances resulting from weathering processes. The presence of secondary carbonates in samples which give no apparent evidence of weathering was noted during pyrolysis experiments, despite the 'normal' total carbon abundances. In selected cases, the surfaces of weathered samples may contain up to a factor of two greater carbon content than the interior. Variations in carbon abundances may reflect the degree of weathering and the amount of secondary minerals present. One of the surprises of this study is that the majority of the Antarctic meteorites studied do not exhibit total carbon and sulfur abundances outside the ranges previously observed for falls.

Zebrafish as a model for monocarboxyl transporter 8-deficiency.

PubMed

Vatine, Gad David; Zada, David; Lerer-Goldshtein, Tali; Tovin, Adi; Malkinson, Guy; Yaniv, Karina; Appelbaum, Lior

2013-01-04

Allan-Herndon-Dudley syndrome (AHDS) is a severe psychomotor retardation characterized by neurological impairment and abnormal thyroid hormone (TH) levels. Mutations in the TH transporter, monocarboxylate transporter 8 (MCT8), are associated with AHDS. MCT8 knock-out mice exhibit impaired TH levels; however, they lack neurological defects. Here, the zebrafish mct8 gene and promoter were isolated, and mct8 promoter-driven transgenic lines were used to show that, similar to humans, mct8 is primarily expressed in the nervous and vascular systems. Morpholino-based knockdown and rescue experiments revealed that MCT8 is strictly required for neural development in the brain and spinal cord. This study shows that MCT8 is a crucial regulator during embryonic development and establishes the first vertebrate model for MCT8 deficiency that exhibits a neurological phenotype.

Frequency stability improvement for piezoresistive micromechanical oscillators via synchronization

NASA Astrophysics Data System (ADS)

Pu, Dong; Huan, Ronghua; Wei, Xueyong

2017-03-01

Synchronization phenomenon first discovered in Huygens' clock shows that the rhythms of oscillating objects can be adjusted via an interaction. Here we show that the frequency stability of a piezoresistive micromechanical oscillator can be enhanced via synchronization. The micromechanical clamped-clamped beam oscillator is built up using the electrostatic driving and piezoresistive sensing technique and the synchronization phenomenon is observed after coupling it to an external oscillator. An enhancement of frequency stability is obtained in the synchronization state. The influences of the synchronizing perturbation intensity and frequency detuning applied on the oscillator are studied experimentally. A theoretical analysis of phase noise leads to an analytical formula for predicting Allan deviation of the frequency output of the piezoresistive oscillator, which successfully explains the experimental observations and the mechanism of frequency stability enhancement via synchronization.

Analytic model for the long-term evolution of circular Earth satellite orbits including lunar node regression

NASA Astrophysics Data System (ADS)

Zhu, Ting-Lei; Zhao, Chang-Yin; Zhang, Ming-Jiang

2017-04-01

This paper aims to obtain an analytic approximation to the evolution of circular orbits governed by the Earth's J2 and the luni-solar gravitational perturbations. Assuming that the lunar orbital plane coincides with the ecliptic plane, Allan and Cook (Proc. R. Soc. A, Math. Phys. Eng. Sci. 280(1380):97, 1964) derived an analytic solution to the orbital plane evolution of circular orbits. Using their result as an intermediate solution, we establish an approximate analytic model with lunar orbital inclination and its node regression be taken into account. Finally, an approximate analytic expression is derived, which is accurate compared to the numerical results except for the resonant cases when the period of the reference orbit approximately equals the integer multiples (especially 1 or 2 times) of lunar node regression period.

Quantum cascade laser based sensor for open path measurement of atmospheric trace gases

NASA Astrophysics Data System (ADS)

Deng, Hao; Sun, Juan; Liu, Ningwu; Ding, Junya; Chao, Zhou; Zhang, Lei; Li, Jingsong

2017-02-01

A sensitive open-path gas sensor employing a continuous-wave (CW) distributed feedback (DFB) quantum cascade laser (QCL) and direct absorption spectroscopy (DAS) was demonstrated for simultaneously measurements of atmospheric CO and N2O. Two interference free absorption lines located at 2190.0175 cm-1 and 2190.3498 cm-1 were selected for CO and N2O concentration measurements, respectively. The Allan variance analysis technique was performed to investigate the long-term performance of the QCL sensor system. The results indicate that a detection limit of 9.92 ppb for CO and 7.7 ppb for N2O with 1-s integration time were achieved, which can be further improved to 1.5 ppb and 1.1 ppb by increasing the average time up to 80 s.

Frequency Measurements of Superradiance from the Strontium Clock Transition

NASA Astrophysics Data System (ADS)

Norcia, Matthew A.; Cline, Julia R. K.; Muniz, Juan A.; Robinson, John M.; Hutson, Ross B.; Goban, Akihisa; Marti, G. Edward; Ye, Jun; Thompson, James K.

2018-04-01

We present the first characterization of the spectral properties of superradiant light emitted from the ultranarrow, 1-mHz-linewidth optical clock transition in an ensemble of cold Sr 87 atoms. Such a light source has been proposed as a next-generation active atomic frequency reference, with the potential to enable high-precision optical frequency references to be used outside laboratory environments. By comparing the frequency of our superradiant source to that of a state-of-the-art cavity-stabilized laser and optical lattice clock, we observe a fractional Allan deviation of 6.7 (1 )×10-16 at 1 s of averaging, establish absolute accuracy at the 2-Hz (4 ×10-15 fractional frequency) level, and demonstrate insensitivity to key environmental perturbations.

698-nm diode laser with 1-Hz linewidth

NASA Astrophysics Data System (ADS)

Chen, Long; Zhang, Linbo; Xu, Guanjun; Liu, Jun; Dong, Ruifang; Liu, Tao

2017-01-01

Two diode lasers at 698 nm are separately locked to two independent optical reference cavities with a finesse of about 128,000 by the Pound-Drever-Hall method. The more accurate coefficient between voltage and frequency of the error signal is measured, with which quantitative evaluation of the effect of many noises on the frequency stability can be made much more conveniently. A temperature-insensitive method is taken to reduce the effect of residual amplitude modulation on laser frequency stability. With an active fiber noise cancellation, the optical heterodyne beat between two independent lasers shows that the linewidth of one diode laser reaches 1 Hz. The fractional Allan deviation removed linear frequency shift less than 30 mHz/s is below 2.6×10-15 with 1- to 100-s average time.

Cumberland Falls chondritic inclusions. III - Consortium study of relationship to inclusions in Allan Hills 78113 aubrite

NASA Astrophysics Data System (ADS)

Lipschutz, Michael E.; Verkouteren, R. Michael; Sears, Derek W. G.; Hasan, Fouad A.; Prinz, Martin.; Weisberg, M. K.; Nehru, Cherukupalli E.; Delaney, Jeremy S.; Grossman, Lawrence; Boily, Michel

1988-07-01

The contents of Ag, Au, Bi, Cd, Co, Cs, Ga, In, Rb, Sb, Se, Te, Tl, U, and Zn in large chondritic clasts from the Cumbersand Falls aubrite were determined by radiochemical neutron activation analysis, and the results, together with the results of a mineralogical investigation, were compared with respective data obtained for three primitive inclusions from the ALH A78113 aubrite. The results indicated that the clasts from both aubrite sources constitute a single chondritic suite. The analyses data, together with the results of thermoluminescence data for Cumberland Falls chondritic inclusions and achondritic host, indicate that inclusions in Cumberland Falls and in ALH A78113 aubrite represent a primitive chondrite sample suite whose properties were established during primary nebular accretion and condensation over a broad redox range.

Sub-picosecond timing fluctuation suppression in laser-based atmospheric transfer of microwave signal using electronic phase compensation

NASA Astrophysics Data System (ADS)

Chen, Shijun; Sun, Fuyu; Bai, Qingsong; Chen, Dawei; Chen, Qiang; Hou, Dong

2017-10-01

We demonstrated a timing fluctuation suppression in outdoor laser-based atmospheric radio-frequency transfer over a 110 m one-way free-space link using an electronic phase compensation technique. Timing fluctuations and Allan Deviation are both measured to characterize the instability of transferred frequency incurred during the transfer process. With transferring a 1 GHz microwave signal over a timing fluctuation suppressed transmission link, the total root-mean-square (rms) timing fluctuation was measured to be 920 femtoseconds in 5000 s, with fractional frequency instability on the order of 1 × 10-12 at 1 s, and order of 2 × 10-16 at 1000 s. This atmospheric frequency transfer scheme with the timing fluctuation suppression technique can be used to fast build an atomic clock-based frequency free-space transmission link since its stability is superior to a commercial Cs and Rb clock.

Advancing Navigation, Timing, and Science with the Deep Space Atomic Clock

NASA Technical Reports Server (NTRS)

Ely, Todd A.; Seubert, Jill; Bell, Julia

2014-01-01

NASA's Deep Space Atomic Clock mission is developing a small, highly stable mercury ion atomic clock with an Allan deviation of at most 1e-14 at one day, and with current estimates near 3e-15. This stability enables one-way radiometric tracking data with accuracy equivalent to and, in certain conditions, better than current two-way deep space tracking data; allowing a shift to a more efficient and flexible one-way deep space navigation architecture. DSAC-enabled one-way tracking will benefit navigation and radio science by increasing the quantity and quality of tracking data. Additionally, DSAC would be a key component to fully-autonomous onboard radio navigation useful for time-sensitive situations. Potential deep space applications of DSAC are presented, including orbit determination of a Mars orbiter and gravity science on a Europa flyby mission.

Femtosecond-level timing fluctuation suppression in atmospheric frequency transfer with passive phase conjunction correction.

PubMed

Sun, Fuyu; Hou, Dong; Zhang, Danian; Tian, Jie; Hu, Jianguo; Huang, Xianhe; Chen, Shijun

2017-09-04

We demonstrate femtosecond-level timing fluctuation suppression in indoor atmospheric comb-based frequency transfer with a passive phase conjunction correction technique. Timing fluctuations and Allan deviations are both measured to characterize the excess frequency instability incurred during the frequency transfer process. By transferring a 2 GHz microwave over a 52-m long free-space link in 5000 s, the total root-mean-square (RMS) timing fluctuation was measured to be about 280 fs with a fractional frequency instability on the order of 3 × 10 -13 at 1 s and 6 × 10 -17 at 1000 s. This atmospheric comb-based frequency transfer with passive phase conjunction correction can be used to build an atomic clock-based free-space frequency transmission link because its instability is less than that of a commercial Cs or H-master clock.

A 920-kilometer optical fiber link for frequency metrology at the 19th decimal place.

PubMed

Predehl, K; Grosche, G; Raupach, S M F; Droste, S; Terra, O; Alnis, J; Legero, Th; Hänsch, T W; Udem, Th; Holzwarth, R; Schnatz, H

2012-04-27

Optical clocks show unprecedented accuracy, surpassing that of previously available clock systems by more than one order of magnitude. Precise intercomparisons will enable a variety of experiments, including tests of fundamental quantum physics and cosmology and applications in geodesy and navigation. Well-established, satellite-based techniques for microwave dissemination are not adequate to compare optical clocks. Here, we present phase-stabilized distribution of an optical frequency over 920 kilometers of telecommunication fiber. We used two antiparallel fiber links to determine their fractional frequency instability (modified Allan deviation) to 5 × 10(-15) in a 1-second integration time, reaching 10(-18) in less than 1000 seconds. For long integration times τ, the deviation from the expected frequency value has been constrained to within 4 × 10(-19). The link may serve as part of a Europe-wide optical frequency dissemination network.

Performance of Planar-Waveguide External Cavity Laser for Precision Measurements

NASA Technical Reports Server (NTRS)

Numata, Kenji; Camp, Jordan; Krainak, Michael A.; Stolpner, Lew

2010-01-01

A 1542-nm planar-waveguide external cavity laser (PW-ECL) is shown to have a sufficiently low level of frequency and intensity noise to be suitable for precision measurement applications. The frequency noise and intensity noise of the PW-ECL was comparable or better than the nonplanar ring oscillator (NPRO) and fiber laser between 0.1 mHz to 100 kHz. Controllability of the PW-ECL was demonstrated by stabilizing its frequency to acetylene (13C2H2) at 10(exp -13) level of Allan deviation. The PW-ECL also has the advantage of the compactness of a standard butterfly package, low cost, and a simple design consisting of a semiconductor gain media coupled to a planar-waveguide Bragg reflector. These features would make the PW-ECL suitable for precision measurements, including compact optical frequency standards, space lidar, and space interferometry

Dual quantum cascade laser-based sensor for simultaneous NO and NO2 detection using a wavelength modulation-division multiplexing technique

NASA Astrophysics Data System (ADS)

Yu, Yajun; Sanchez, Nancy P.; Yi, Fan; Zheng, Chuantao; Ye, Weilin; Wu, Hongpeng; Griffin, Robert J.; Tittel, Frank K.

2017-05-01

A sensor system capable of simultaneous measurements of NO and NO2 was developed using a wavelength modulation-division multiplexing (WMDM) scheme and multi-pass absorption spectroscopy. A continuous wave (CW), distributed-feedback (DFB) quantum cascade laser (QCL) and a CW external-cavity (EC) QCL were employed for targeting a NO absorption doublet at 1900.075 cm-1 and a NO2 absorption line at 1630.33 cm-1, respectively. Simultaneous detection was realized by modulating both QCLs independently at different frequencies and demodulating the detector signals with LabView-programmed lock-in amplifiers. The sensor operated at a reduced pressure of 40 Torr and a data sampling rate of 1 Hz. An Allan-Werle deviation analysis indicated that the minimum detection limits of NO and NO2 can reach sub-ppbv concentration levels with averaging times of 100 and 200 s, respectively.

Low-frequency gravitational wave detection via double optical clocks in space

NASA Astrophysics Data System (ADS)

Su, Jianfeng; Wang, Qiang; Wang, Qinghua; Jetzer, Philippe

2018-04-01

We propose a Doppler tracking system for gravitational wave detection via double optical clocks in space (DOCS). In this configuration two spacecrafts (each containing an optical clock) are launched to space for Doppler shift observations. Compared to the similar attempt of gravitational wave detection in the Cassini mission, the radio signal of DOCS that contains the relative frequency changes avoids completely noise effects due for instance to troposphere, ionosphere, ground-based antenna and transponder. Given the high stabilities of the two optical clocks (Allan deviation  ∼ 4.1× 10-17 @ 1000 s), an overall estimated sensitivity of 5 × 10-19 could be achieved with an observation time of 2 yr, and would allow to detect gravitational waves in the frequency range from  ∼10‑4 Hz to  ∼10‑2 Hz.

Operating and environmental characteristics of Sigma Tau hydrogen masers used in the Very Long Baseline Array (VLBA)

NASA Technical Reports Server (NTRS)

Tucker, T. K.

1989-01-01

Presented here are the results obtained from performance evaluation of a pair of Sigma Tau Standards Corporation Model VLBA-112 active hydrogen maser frequency standards. These masers were manufactured for the National Radio Astronomy Observatory (NRAO) for use on the Very Long Baseline Array (VLBA) project and were furnished to the Jet Propulsion Laboratory (JPL) for the purpose of these tests. Tests on the two masers were performed in the JPL Frequency Standards Laboratory (FSL) and included the characterization of output frequency stability versus environmental factors such as temperature, humidity, magnetic field, and barometric pressure. The performance tests also included the determination of phase noise and Allan variance using both FSL and Sigma Tau masers as references. All tests were conducted under controlled laboratory conditions, with only the desired environmental and operational parameters varied to determine sensitivity to external environment.

Novel polymer carriers and gene constructs for treatment of myocardial ischemia and infarction.

PubMed

Yockman, James W; Kastenmeier, Andrew; Erickson, Harold M; Brumbach, Jonathan G; Whitten, Matthew G; Albanil, Aida; Li, Dean Y; Kim, Sung Wan; Bull, David A

2008-12-18

The number one cause of mortality in the US is cardiovascular related disease. Future predictions do not see a reduction in this rate especially with the continued rise in obesity [P. Poirier, et al., Obesity and cardiovascular disease: pathophysiology, evaluation, and effect of weight loss, Arterioscler Thromb Vasc Biol. 26(5), (2006) 968-976.; K. Obunai, S. Jani, G.D. Dangas, Cardiovascular morbidity and mortality of the metabolic syndrome, Med.Clin. North Am., 91(6), (2007) 1169-1184]. Even so, potential molecular therapeutic targets for cardiac gene delivery are in no short supply thanks to continuing advances in molecular cardiology. However, efficient and safe delivery remains a bottleneck in clinical gene therapy [O.J. Muller, H.A. Katus, R. Bekeredjian, Targeting the heart with gene therapy-optimized gene delivery methods, Cardiovasc Res, 73(3), (2007) 453-462]. Viral vectors are looked upon favorably for their high transduction efficiency, although their ability to elicit toxic immune responses remains [C.F. McTiernan, et al., Myocarditis following adeno-associated viral gene expression of human soluble TNF receptor (TNFRII-Fc) in baboon hearts, Gene Ther, 14(23), (2007) 1613-1622]. However, this high transduction does not necessarily translate into improved efficacy [X. Hao, et al., Myocardial angiogenesis after plasmid or adenoviral VEGF-A(165) gene transfer in rat myocardial infarction model, Cardiovasc Res., 73(3), (2007) 481-487]. Naked DNA remains the preferred method of DNA delivery to cardiac myocardium and has been explored extensively in clinical trials. The results from these trials have demonstrated efficacy in regard to secondary end-points of reduced symptomatology and perfusion, but have failed to establish significant angiogenesis or an increase in myocardial function [P.B. Shah, D.W. Losordo, Non-viral vectors for gene therapy: clinical trials in cardiovascular disease, Adv Genet, 54, (2005) 339-361]. This may be due in part to reduced

Variability of extragalactic sources: its contribution to the link between ICRF and the future Gaia Celestial Reference Frame

NASA Astrophysics Data System (ADS)

Taris, F.; Damljanovic, G.; Andrei, A.; Souchay, J.; Klotz, A.; Vachier, F.

2018-03-01

Context. The first release of the Gaia catalog is available since 14 September 2016. It is a first step in the realization of the future Gaia reference frame. This reference frame will be materialized by the optical positions of the sources and will be compared with and linked to the International Celestial Reference Frame, materialized by the radio position of extragalactic sources. Aim. As in the radio domain, it can be reasonably postulated that quasar optical flux variations can alert us to potential changes in the source structure. These changes could have important implications for the position of the target photocenters (together with the evolution in time of these centers) and in parallel have consequences for the link of the reference systems. Methods: A set of nine optical telescopes was used to monitor the magnitude variations, often at the same time as Gaia, thanks to the Gaia Observation Forecast Tool. The Allan variances, which are statistical tools widely used in the atomic time and frequency community, are introduced. Results: This work describes the magnitude variations of 47 targets that are suitable for the link between reference systems. We also report on some implications for the Gaia catalog. For 95% of the observed targets, new information about their variability is reported. In the case of some targets that are well observed by the TAROT telescopes, the Allan time variance shows that the longest averaging period of the magnitudes is in the range 20-70 d. The observation period by Gaia for a single target largely exceeds these values, which might be a problem when the magnitude variations exhibit flicker or random walk noises. Preliminary computations show that if the coordinates of the targets studied in this paper were affected by a white-phase noise with a formal uncertainty of about 1 mas (due to astrophysical processes that are put in evidence by the magnitude variations of the sources), it would affect the precision of the link at the

Eight-Channel Continuous Timer

NASA Technical Reports Server (NTRS)

Cole, Steven

2004-01-01

A custom laboratory electronic timer circuit measures the durations of successive cycles of nominally highly stable input clock signals in as many as eight channels, for the purpose of statistically quantifying the small instabilities of these signals. The measurement data generated by this timer are sent to a personal computer running software that integrates the measurements to form a phase residual for each channel and uses the phase residuals to compute Allan variances for each channel. (The Allan variance is a standard statistical measure of instability of a clock signal.) Like other laboratory clock-cycle-measuring circuits, this timer utilizes an externally generated reference clock signal having a known frequency (100 MHz) much higher than the frequencies of the input clock signals (between 100 and 120 Hz). It counts the number of reference-clock cycles that occur between successive rising edges of each input clock signal of interest, thereby affording a measurement of the input clock-signal period to within the duration (10 ns) of one reference clock cycle. Unlike typical prior laboratory clock-cycle-measuring circuits, this timer does not skip some cycles of the input clock signals. The non-cycle-skipping feature is an important advantage because in applications that involve integration of measurements over long times for characterizing nominally highly stable clock signals, skipping cycles can degrade accuracy. The timer includes a field-programmable gate array that functions as a 20-bit counter running at the reference clock rate of 100 MHz. The timer also includes eight 20-bit latching circuits - one for each channel - at the output terminals of the counter. Each transition of an input signal from low to high causes the corresponding latching circuit to latch the count at that instant. Each such transition also sets a status flip-flop circuit to indicate the presence of the latched count. A microcontroller reads the values of all eight status flipflops

A method to precisely measure Ar isotopes and Xe/Kr ratios in air trapped in ice cores for simultaneous ice core dating and mean ocean temperature reconstruction

NASA Astrophysics Data System (ADS)

Yan, Y.; Ng, J.; Higgins, J. A.; Kurbatov, A.; Clifford, H.; Spaulding, N. E.; Mayewski, P. A.; Brook, E.; Bender, M. L.; Severinghaus, J. P.

2017-12-01

Antarctic efforts are underway to find and retrieve ice cores older than 800 thousand years (kyr) by both shallow drilling in "blue ice" areas and classic deep ice coring. Ice stratigraphy at "blue ice" sites is typically disordered, and the high cost of deep drilling mandates rapid reconnaissance drilling (e.g. RAID) with very small sample size. Both approaches therefore require methods of absolute dating on a single piece of ice without stratigraphic context. Here we present a dating method modified from Bender et al. (2008; PNAS) to precisely measure the isotopic composition of argon (36Ar, 38Ar, and 40Ar) in air bubbles trapped in the ice, which changes over time in a known way. Our method has an analytical uncertainty of 110 kyr (1σ) or 10% of the age of the sample, whichever is greater. We measured Ar isotopes from the Allan Hills blue ice areas, East Antarctica, where 1 Ma ice was previously found by Higgins et al. (2015; PNAS). Results show ice as old as 2.7±0.3 million years, but the ice column is stratigraphically disturbed. Hence Allan Hills ice core records should be viewed as a series of "climate snapshots" rather than a continuum. Xenon-to-krypton (Xe/Kr) ratios are also measured in the same aliquot of extracted gas to reconstruct mean ocean temperature (Shackleton et al., 2016; Fall AGU). Preliminary mean ocean temperature in ice older than 1 Ma ranges from -0.3 to -1.2 deg. colder than present with an uncertainty of 0.24 deg., which agrees well with other Pleistocene ocean temperature records (e.g. Rohling et al., 2014; Nature and Elderfield et al., 2012; Science). The observed range is 40% of the glacial-interglacial variability in the 100-kyr climate cycles ( 2 deg.), close to the 50% reduction in the glacial-interglacial δ18O amplitude across the Mid-Pleistocene Transition. Finally, Xe/Kr ratios are found to correlate positively with δD of the ice, implying a coupling between the global ocean temperature and Antarctic temperature throughout

Ultrafast optical ranging using microresonator soliton frequency combs

NASA Astrophysics Data System (ADS)

Trocha, P.; Karpov, M.; Ganin, D.; Pfeiffer, M. H. P.; Kordts, A.; Wolf, S.; Krockenberger, J.; Marin-Palomo, P.; Weimann, C.; Randel, S.; Freude, W.; Kippenberg, T. J.; Koos, C.

2018-02-01

Light detection and ranging is widely used in science and industry. Over the past decade, optical frequency combs were shown to offer advantages in optical ranging, enabling fast distance acquisition with high accuracy. Driven by emerging high-volume applications such as industrial sensing, drone navigation, or autonomous driving, there is now a growing demand for compact ranging systems. Here, we show that soliton Kerr comb generation in integrated silicon nitride microresonators provides a route to high-performance chip-scale ranging systems. We demonstrate dual-comb distance measurements with Allan deviations down to 12 nanometers at averaging times of 13 microseconds along with ultrafast ranging at acquisition rates of 100 megahertz, allowing for in-flight sampling of gun projectiles moving at 150 meters per second. Combining integrated soliton-comb ranging systems with chip-scale nanophotonic phased arrays could enable compact ultrafast ranging systems for emerging mass applications.

Deviations from uniform power law scaling in nonstationary time series

NASA Technical Reports Server (NTRS)

Viswanathan, G. M.; Peng, C. K.; Stanley, H. E.; Goldberger, A. L.

1997-01-01

A classic problem in physics is the analysis of highly nonstationary time series that typically exhibit long-range correlations. Here we test the hypothesis that the scaling properties of the dynamics of healthy physiological systems are more stable than those of pathological systems by studying beat-to-beat fluctuations in the human heart rate. We develop techniques based on the Fano factor and Allan factor functions, as well as on detrended fluctuation analysis, for quantifying deviations from uniform power-law scaling in nonstationary time series. By analyzing extremely long data sets of up to N = 10(5) beats for 11 healthy subjects, we find that the fluctuations in the heart rate scale approximately uniformly over several temporal orders of magnitude. By contrast, we find that in data sets of comparable length for 14 subjects with heart disease, the fluctuations grow erratically, indicating a loss of scaling stability.

High spectral purity Kerr frequency comb radio frequency photonic oscillator

PubMed Central

Liang, W.; Eliyahu, D.; Ilchenko, V. S.; Savchenkov, A. A.; Matsko, A. B.; Seidel, D.; Maleki, L.

2015-01-01

Femtosecond laser-based generation of radio frequency signals has produced astonishing improvements in achievable spectral purity, one of the basic features characterizing the performance of an radio frequency oscillator. Kerr frequency combs hold promise for transforming these lab-scale oscillators to chip-scale level. In this work we demonstrate a miniature 10 GHz radio frequency photonic oscillator characterized with phase noise better than −60 dBc Hz−1 at 10 Hz, −90 dBc Hz−1 at 100 Hz and −170 dBc Hz−1 at 10 MHz. The frequency stability of this device, as represented by Allan deviation measurements, is at the level of 10−10 at 1–100 s integration time—orders of magnitude better than existing radio frequency photonic devices of similar size, weight and power consumption. PMID:26260955

Densities and Viscosities of the Quinary System: Cyclohexane (1) + \\varvec{m} -Xylene (2) + Cyclooctane (3) + Chlorobenzene (4) + Decane (5) and Its Quaternary Subsystems at 308.15 K and 313.15 K

NASA Astrophysics Data System (ADS)

Hamzehlouia, Sepehr; Asfour, Abdul-Fattah A.

2013-06-01

The volumetric and viscometric properties of the quinary system: cyclohexane + m -xylene + cyclooctane + chlorobenzene + decane, were measured over the entire composition range at 308.15 K and 313.15 K. The experimental data obtained in the course of the present study were employed to analyze the predictive capability of six semi-theoretical and empirical well-known viscosity models reported in the literature, namely, the generalized McAllister three-body interaction model, the pseudo- binary McAllister model, the group contribution model, the generalized corresponding states principle model, the Allan and Teja correlation, and the Grunberg and Nissan law of viscosity. The predictive capabilities of the models were compared using the percentage average absolute deviation (%AAD). The final results showed that the generalized McAllister model gives the lowest AADs of 3.3 % and 3.7 % at 308.15 K and 313.15 K, respectively.

Compact CH 4 sensor system based on a continuous-wave, low power consumption, room temperature interband cascade laser

DOE PAGES

Dong, Lei; Li, Chunguang; Sanchez, Nancy P.; ...

2016-01-05

A tunable diode laser absorption spectroscopy-based methane sensor, employing a dense-pattern multi-pass gas cell and a 3.3 µm, CW, DFB, room temperature interband cascade laser (ICL), is reported. The optical integration based on an advanced folded optical path design and an efficient ICL control system with appropriate electrical power management resulted in a CH 4 sensor with a small footprint (32 x 20 x 17 cm 3) and low-power consumption (6 W). Polynomial and least-squares fit algorithms are employed to remove the baseline of the spectral scan and retrieve CH 4 concentrations, respectively. An Allan-Werle deviation analysis shows that themore » measurement precision can reach 1.4 ppb for a 60 s averaging time. Continuous measurements covering a seven-day period were performed to demonstrate the stability and robustness of the reported CH 4 sensor system.« less

Stable fiber-optic time transfer by active radio frequency phase locking.

PubMed

Yin, Feifei; Wu, Zhongle; Dai, Yitang; Ren, Tianpeng; Xu, Kun; Lin, Jintong; Tang, Geshi

2014-05-15

In this Letter we demonstrate a fiber link capable of stable time signal transfer utilizing our active long-distance radio frequency (RF) stabilization technology. Taking advantage of the chromatic dispersion in optical fiber, our scheme compensates dynamically the link delay variation by tuning the optical carrier wavelength to phase lock a round-trip RF reference. Since the time signal and the RF reference are carried by the same optical carrier, a highly stable time transfer is achieved at the same time. Experimentally, we demonstrate a stability of the time signal transfer over 50-km fiber with a time deviation of 40 ps at 1-s average and 2.3 ps at 1000-s average. The performance of the RF reference delivery is also tested, with an Allan deviation of 2×10(-15) at 1000-s average. According to our proposal, a simultaneous stable time and frequency transfer is expected.

Compact CH 4 sensor system based on a continuous-wave, low power consumption, room temperature interband cascade laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Lei; Li, Chunguang; Sanchez, Nancy P.

A tunable diode laser absorption spectroscopy-based methane sensor, employing a dense-pattern multi-pass gas cell and a 3.3 µm, CW, DFB, room temperature interband cascade laser (ICL), is reported. The optical integration based on an advanced folded optical path design and an efficient ICL control system with appropriate electrical power management resulted in a CH 4 sensor with a small footprint (32 x 20 x 17 cm 3) and low-power consumption (6 W). Polynomial and least-squares fit algorithms are employed to remove the baseline of the spectral scan and retrieve CH 4 concentrations, respectively. An Allan-Werle deviation analysis shows that themore » measurement precision can reach 1.4 ppb for a 60 s averaging time. Continuous measurements covering a seven-day period were performed to demonstrate the stability and robustness of the reported CH 4 sensor system.« less

Mineralization of Bacteria in Terrestrial Basaltic Rocks: Comparison With Possible Biogenic Features in Martian Meteorite Allan Hills 84001

NASA Technical Reports Server (NTRS)

Thomas-Keprta, K. L.; McKay, D. S.; Wentworth, S. J.; Stevens, T. O.; Taunton, A. E.; Allen, C. C.; Gibson, E. K., Jr.; Romanek, C. S.

1998-01-01

The identification of biogenic features altered by diagenesis or mineralization is important in determining whether specific features in terrestrial rocks and in meteorites may have a biogenic origin. Unfortunately, few studies have addressed the formation of biogenic features in igneous rocks, which may be important to these phenomena, including the controversy over possible biogenic features in basaltic martian meteorite ALH84001. To explore the presence of biogenic features in igneous rocks, we examined microcosms growing in basaltic small-scale experimental growth chambers or microcosms. Microbial communities were harvested from aquifers of the Columbia River Basalt (CRB) group and grown in a microcosm containing unweathered basalt chips and groundwater (technique described in. These microcosms simulated natural growth conditions in the deep subsurface of the CRB, which should be a good terrestrial analog for any putative martian subsurface ecosystem that may have once included ALH84001. Here we present new size measurements and photomicrographs comparing the putative martian fossils to biogenic material in the CRB microcosms. The range of size and shapes of the biogenic features on the CRB microcosm chips overlaps with and is similar to those on ALH84001 chips. Although this present work does not provide evidence for the biogenicity of ALH84001 features, we believe that, based on criteria of size, shape, and general morphology, a biogenic interpretation for the ALH84001 features remains plausible.

An apatite-rich, ferroan, mafic lithology from lunar meteorite ALHA81005

NASA Technical Reports Server (NTRS)

Goodrich, C. A.; Taylor, G. J.; Keil, K.

1985-01-01

Antarctic meteorite Allan Hills A81005 is a polymict, anorthositic regolith breccia of lunar origin. Most lithic clasts in the meteorite 81005 are similar to those from other lunar rocks. However, some, such as 'hyperferroan' anorthosites, have not been reported before the discovery of 81005. On the basis of the composition of some granulitic polymict breccia clasts, it appears possible that other new lithologies are present. In the present paper, a description is provided of an unusual, apatite-rich, ferroan, mafic lithology, and its origin is discussed. Three clasts which appeared to contain two minerals were separated as samples ,32 ,28 and ,27. It is found in a study that the clast in ,32 and ,28 is an apatite-rich ferroan anorthositic troctolite which is probably pristine. This rock is unique among lunar samples. On the basis of an evaluation of the significance of the results of the study, it is concluded that complex processes were apparently involved in the evolution of the primitive lunar crust.

On Dreams and Motivation: Comparison of Freud’s and Hobson’s Views

PubMed Central

Boag, Simon

2017-01-01

The merits of Freudian dream theory continue to be debated and both supporters and critics appeal to empirical evidence to support their respective positions. What receives much less attention is the theoretical coherency of either Freudian dream theory or alternative perspectives. This paper examines Freudian dream theory and J. Allan Hobson’s alternative position by addressing the role of motivation in dreams. This paper first discusses motivation in Freudian theory and its relation to dreams and disguise-censorship. The role of motivation in Hobson’s theory is then considered. Hobson’s claim that dream plot and content selection is random and based on design error and functional imbalance is then discussed in relation to the protoconsciousness theory proposal that dreams serve an adaptive function. While there are apparent inconsistencies in Hobson’s position, his appeal to emotions and instincts provides a preliminary platform for understanding the role of motivation in dreams that is consonant with the Freudian position. PMID:28111554

Hand-writing motion tracking with vision-inertial sensor fusion: calibration and error correction.

PubMed

Zhou, Shengli; Fei, Fei; Zhang, Guanglie; Liu, Yunhui; Li, Wen J

2014-08-25

The purpose of this study was to improve the accuracy of real-time ego-motion tracking through inertial sensor and vision sensor fusion. Due to low sampling rates supported by web-based vision sensor and accumulation of errors in inertial sensors, ego-motion tracking with vision sensors is commonly afflicted by slow updating rates, while motion tracking with inertial sensor suffers from rapid deterioration in accuracy with time. This paper starts with a discussion of developed algorithms for calibrating two relative rotations of the system using only one reference image. Next, stochastic noises associated with the inertial sensor are identified using Allan Variance analysis, and modeled according to their characteristics. Finally, the proposed models are incorporated into an extended Kalman filter for inertial sensor and vision sensor fusion. Compared with results from conventional sensor fusion models, we have shown that ego-motion tracking can be greatly enhanced using the proposed error correction model.

Maintenance of time and frequency in the Jet Propulsion Laboratory's Deep Space Network using the Global Positioning System

NASA Technical Reports Server (NTRS)

Clements, P. A.; Borutzki, S. E.; Kirk, A.

1984-01-01

The Deep Space Network (DSN), managed by the Jet Propulsion Laboratory for NASA, must maintain time and frequency within specified limits in order to accurately track the spacecraft engaged in deep space exploration. Various methods are used to coordinate the clocks among the three tracking complexes. These methods include Loran-C, TV Line 10, Very Long Baseline Interferometry (VLBI), and the Global Positioning System (GPS). Calculations are made to obtain frequency offsets and Allan variances. These data are analyzed and used to monitor the performance of the hydrogen masers that provide the reference frequencies for the DSN Frequency and Timing System (DFT). Areas of discussion are: (1) a brief history of the GPS timing receivers in the DSN, (2) a description of the data and information flow, (3) data on the performance of the DSN master clocks and GPS measurement system, and (4) a description of hydrogen maser frequency steering using these data.

Performance of a GaAlAs laser diode stabilized on a hyperfine component of two-photon transitions in rubidium at 778 nm

NASA Astrophysics Data System (ADS)

Felder, Raymond; Touahri, D.; Acef, Ouali; Hilico, L.; Zondy, Jean-Jacques; Clairon, Andre; de Beauvoir, Beatrice; Biraben, Francois; Julien, Lucile; Nez, Francois; Millerioux, Yves P.

1995-04-01

The absolute frequency measurement of each hyperfine component of the 5S3/2 and 5S5/2 levels in rubidium was done at ENS more than one year ago using Ti-Sa lasers. We built two devices based on diode lasers to study some metrological properties. We measure the frequency differences between hyperfine components of the 5S5/2 level and we calculate the corresponding hyperfine constants. We also measure the frequency interval between the 5S3/2 and 5S5/2 levels using a Schottky diode. The measured stability in terms of Allan variance is 3*10-13t-1/2 up to 2000 s. The light shift is investigated and the difference between our two systems is 1.7 kHz. The repeatability of one system is better than 10-12 and will allow the absolute frequency measurement at this level via the LPTF frequency synthesis chain.

Long-term maintenance of the carrier-envelope phase coherence of a femtosecond laser.

PubMed

Kim, Eok Bong; Lee, Jae-Hwan; Lee, Won-Kyu; Luu, Tran Trung; Nam, Chang Hee

2010-12-06

The long-term carrier-envelope phase (CEP) coherence of a femtosecond laser with same pulse-to-pulse CEP value, obtained using the direct locking method, is demonstrated by employing a quasi-common-path interferometer (QPI). For the evaluation of the CEP stability, the phase noise properties of a femtosecond laser with the CEP stabilized using a QPI are compared with those obtained using a Mach-Zehnder f-2f interferometer, for which the phase power spectral density and the Allan deviation were calculated from the beat signals of the interferometers. With the improved CEP stability, the long-term CEP coherent signal with an accumulated phase noise well below 1 radian can be maintained for more than 56 hours, i.e., the CEP coherence is preserved without a phase cycle slip for more than 1.6 × 10(13) pulses at a repetition rate of 80 MHz. The relative stability is also estimated to be approximately 1.4 × 10(-22) at a central wavelength of 790 nm.

Ppb-level formaldehyde detection using a CW room-temperature interband cascade laser and a miniature dense pattern multipass gas cell

DOE PAGES

Dong, Lei; Yu, Yajun; Li, Chunguang; ...

2015-07-27

A ppb-level formaldehyde (H 2CO) sensor was developed using a thermoelectrically cooled (TEC), continuous-wave (CW) room temperature interband cascade laser (ICL) emitting at 3.59 μm and a miniature dense pattern multipass gas cell with >50 m optical path length. Performance of the sensor was investigated with two measurement schemes: direct absorption (DAS) and wavelength modulation spectroscopy (WMS). With an integration time of less than 1.5 second, a detection limit of ~3 ppbv for H 2CO measurement with precision of 1.25 ppbv for DAS and 0.58 ppbv for WMS, respectively, was achieved without zero air based background subtraction. An Allan-Werle variancemore » analysis indicated that the precisions can be further improved to 0.26 ppbv @ 300s for DAS and 69 pptv @ 90 s for WMS, respectively. Finally, a side-by-side comparison between two measurement schemes is also discussed in detail.« less

Thermal effects of an ICL-based mid-infrared CH4 sensor within a wide atmospheric temperature range

NASA Astrophysics Data System (ADS)

Ye, Weilin; Zheng, Chuantao; Sanchez, Nancy P.; Girija, Aswathy V.; He, Qixin; Zheng, Huadan; Griffin, Robert J.; Tittel, Frank K.

2018-03-01

The thermal effects of an interband cascade laser (ICL) based mid-infrared methane (CH4) sensor that uses long-path absorption spectroscopy were studied. The sensor performance in the laboratory at a constant temperature of ∼25 °C was measured for 5 h and its Allan deviation was ∼2 ppbv with a 1 s averaging time. A LabVIEW-based simulation program was developed to study thermal effects on infrared absorption and a temperature compensation technique was developed to minimize these effects. An environmental test chamber was employed to investigate the thermal effects that occur in the sensor system with variation of the test chamber temperature between 10 and 30 °C. The thermal response of the sensor in a laboratory setting was observed using a 2.1 ppm CH4 standard gas sample. Indoor/outdoor CH4 measurements were conducted to evaluate the sensor performance within a wide atmospheric temperature range.

Using pattern recognition as a method for predicting extreme events in natural and socio-economic systems

NASA Astrophysics Data System (ADS)

Intriligator, M.

2011-12-01

Vladimir (Volodya) Keilis-Borok has pioneered the use of pattern recognition as a technique for analyzing and forecasting developments in natural as well as socio-economic systems. Keilis-Borok's work on predicting earthquakes and landslides using this technique as a leading geophysicist has been recognized around the world. Keilis-Borok has also been a world leader in the application of pattern recognition techniques to the analysis and prediction of socio-economic systems. He worked with Allan Lichtman of American University in using such techniques to predict presidential elections in the U.S. Keilis-Borok and I have worked together with others on the use of pattern recognition techniques to analyze and to predict socio-economic systems. We have used this technique to study the pattern of macroeconomic indicators that would predict the end of an economic recession in the U.S. We have also worked with officers in the Los Angeles Police Department to use this technique to predict surges of homicides in Los Angeles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Lei; Yu, Yajun; Li, Chunguang

A ppb-level formaldehyde (H 2CO) sensor was developed using a thermoelectrically cooled (TEC), continuous-wave (CW) room temperature interband cascade laser (ICL) emitting at 3.59 μm and a miniature dense pattern multipass gas cell with >50 m optical path length. Performance of the sensor was investigated with two measurement schemes: direct absorption (DAS) and wavelength modulation spectroscopy (WMS). With an integration time of less than 1.5 second, a detection limit of ~3 ppbv for H 2CO measurement with precision of 1.25 ppbv for DAS and 0.58 ppbv for WMS, respectively, was achieved without zero air based background subtraction. An Allan-Werle variancemore » analysis indicated that the precisions can be further improved to 0.26 ppbv @ 300s for DAS and 69 pptv @ 90 s for WMS, respectively. Finally, a side-by-side comparison between two measurement schemes is also discussed in detail.« less

Toward a US technology policy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Branscomb, L.M.

1991-01-01

The search for a political and economic middle ground between a laissez-faire economic policy and a full-blown industrial policy made little progress until quite recently. A new approach, which appears to have the makings of a consensus, urges the development of a U.S. technology policy, in which the federal government helps develop and provide access to the technical knowledge on which the competitiveness of commercial enterprises depends. Among the advocates of an explicit technology policy are science and technology policy are science and technology policy scholars, civilian high-tech industry executives (including members of the private Council on Competitiveness), some microeconomists,more » and several influential technology advocates within the Bush administration, including Assistant to the President for Science and Technology D. Allan Bromley, Department of Commerce Undersecretary for Technology Robert White, and former National Science Foundation director Erich Bloch. This article addresses the basics of a technology policy and the steps needed to implement it.« less

Frequency stabilization of a 1083 nm fiber laser to {sup 4}He transition lines with optical heterodyne saturation spectroscopies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, W.; Peng, X., E-mail: xiangpeng@pku.edu.cn; Li, W.

2014-07-15

Two kinds of optical heterodyne saturation spectroscopies, namely, frequency modulation spectroscopy (FMS) and modulation transfer spectroscopy (MTS), are demonstrated for locking a fiber laser to the transition lines of metastable {sup 4}He atoms around 1083 nm. The servo-loop error signals of FMS and MTS for stabilizing laser frequency are optimized by studying the dependence of the peak-to-peak amplitude and slope on the optical power of pump and probe beams. A comparison of the stabilization performances of FMS/MTS and polarization spectroscopy (PS) is presented, which shows that MTS exhibits relatively superior performance with the least laser frequency fluctuation due to itsmore » flat-background dispersive signal, originated from the four-wave mixing process. The Allan deviation of the stabilized laser frequency is 5.4 × 10{sup −12}@100 s with MTS for data acquired in 1000 s, which is sufficiently applicable for fields like laser cooling, optical pumping, and optical magnetometry.« less

Basaltic volcanism on the eucrite parent body - Petrology and chemistry of the polymict eucrite ALHA80102

NASA Technical Reports Server (NTRS)

Treiman, A. H.; Drake, M. J.

1985-01-01

The polymict eucrite meteorite ALHA80102 is an unequilibrated breccia of basaltic and gabbroic clasts in a fragmental matrix. Clasts include basalts of many textural types, cumulate gabbro, black 'glass', and ferroan troctolite (plagioclase, silica, Fe-rich olivine, ilmenite, mesostasis). Ferroan troctolite has not been previously reported from eucrites or howardites; it is interpreted as the end-product of fractional crystallization of eucritic magmas. Bulk and trace element compositions (by electron microprobe and INAA) of clasts and matrix from ALHA80102 are similar to those of other eucrites; the meteorite contains clasts similar to Juvinas and to Stannern. A clast of cumulate eucrite gabbro is enriched in the light rare earths (La/Lu = 2XCI). This clast is interpreted as an unrepresentative sample of metamorphically equilibrated gabbro; LREE-enriched magmas need not be invoked. ALHA80102 is similar to other polymict eucrites from the Allan Hills and may be paired with ALHA76005, ALHA77302, and ALHA78040.

Radio-science performance analysis software

NASA Astrophysics Data System (ADS)

Morabito, D. D.; Asmar, S. W.

1995-02-01

The Radio Science Systems Group (RSSG) provides various support functions for several flight project radio-science teams. Among these support functions are uplink and sequence planning, real-time operations monitoring and support, data validation, archiving and distribution functions, and data processing and analysis. This article describes the support functions that encompass radio-science data performance analysis. The primary tool used by the RSSG to fulfill this support function is the STBLTY program set. STBLTY is used to reconstruct observable frequencies and calculate model frequencies, frequency residuals, frequency stability in terms of Allan deviation, reconstructed phase, frequency and phase power spectral density, and frequency drift rates. In the case of one-way data, using an ultrastable oscillator (USO) as a frequency reference, the program set computes the spacecraft transmitted frequency and maintains a database containing the in-flight history of the USO measurements. The program set also produces graphical displays. Some examples and discussions on operating the program set on Galileo and Ulysses data will be presented.

Radio-Science Performance Analysis Software

NASA Astrophysics Data System (ADS)

Morabito, D. D.; Asmar, S. W.

1994-10-01

The Radio Science Systems Group (RSSG) provides various support functions for several flight project radio-science teams. Among these support functions are uplink and sequence planning, real-time operations monitoring and support, data validation, archiving and distribution functions, and data processing and analysis. This article describes the support functions that encompass radio science data performance analysis. The primary tool used by the RSSG to fulfill this support function is the STBLTY program set. STBLTY is used to reconstruct observable frequencies and calculate model frequencies, frequency residuals, frequency stability in terms of Allan deviation, reconstructed phase, frequency and phase power spectral density, and frequency drift rates. In the case of one-way data, using an ultrastable oscillator (USO) as a frequency reference, the program set computes the spacecraft transmitted frequency and maintains a database containing the in-flight history of the USO measurements. The program set also produces graphical displays. Some examples and discussion on operating the program set on Galileo and Ulysses data will be presented.

Nonlinear and Nonequilibrium Spin Injection in Magnetic Tunneling Junctions

NASA Astrophysics Data System (ADS)

Guo, Hong

2007-03-01

Quantitative analysis of charge and spin quantum transport in spintronic devices requires an atomistic first principles approach that can handle nonlinear and nonequilibrium transport conditions. We have developed an approach for this purpose based on real space density functional theory (DFT) carried out within the Keldysh nonequilibrium Green's function formalism (NEGF). We report theoretical analysis of nonlinear and nonequilibrium spin injection and quantum transport in Fe/MgO/Fe trilayer structures as a function of external bias voltage. Devices with well relaxed atomic structures and with FeO oxidization layers are investigated as a function of external bias voltage. We also report calculations of nonequilibrium spin injection into molecular layers and graphene. Comparisons to experimental data will be presented. Work in collaborations with: Derek Waldron, Vladimir Timochevski (McGill University); Ke Xia (Institute of Physics, Chinese Academy of Science, Beijing, China); Eric Zhu, Jian Wang (University of Hong Kong); Paul Haney, and Allan MacDonald (University of Texas at Austin).

Sublimation: A Mechanism for the Enrichment of Organics in Antarctic Ice

NASA Technical Reports Server (NTRS)

Becker, Luann; McDonald, Gene D.; Glavin, Daniel P.; Bada, Jeffrey L.; Bunch, Theodore E.; Chang, Sherwood (Technical Monitor)

1997-01-01

Recent analyses of the carbonate globules present in the Martian meteorite ALH84001 have detected polycyclic aromatic hydrocarbons (PAHs) at the ppm level. The distribution of PAHs observed in ALH84001 was interpreted as being inconsistent with a terrestrial origin and were claimed to be indigenous to the meteorite, perhaps derived from an ancient Martian biota. However, Becker et al., have examined PAHs in the Martian meteorite EETA79001, in several Antarctic carbonaceous chondrites and Antarctic Allan Hills Ice and detected many of the same PAHs found in ALH84001. The reported presence of L-amino acids of apparent terrestrial origin in the EETA79001 druse material, suggests that this meteorite is contaminated with terrestrial/extraterrestrial organics probably derived from Antarctic ice meltwater that had percolated through the meteorite. The detection of PAHs and L-amino acids in these Martian meteorites suggests that despite storage in the Antarctic ice, selective changes of certain chemical and mineralogical phases has occurred.

AMA- and RWE- Based Adaptive Kalman Filter for Denoising Fiber Optic Gyroscope Drift Signal.

PubMed

Yang, Gongliu; Liu, Yuanyuan; Li, Ming; Song, Shunguang

2015-10-23

An improved double-factor adaptive Kalman filter called AMA-RWE-DFAKF is proposed to denoise fiber optic gyroscope (FOG) drift signal in both static and dynamic conditions. The first factor is Kalman gain updated by random weighting estimation (RWE) of the covariance matrix of innovation sequence at any time to ensure the lowest noise level of output, but the inertia of KF response increases in dynamic condition. To decrease the inertia, the second factor is the covariance matrix of predicted state vector adjusted by RWE only when discontinuities are detected by adaptive moving average (AMA).The AMA-RWE-DFAKF is applied for denoising FOG static and dynamic signals, its performance is compared with conventional KF (CKF), RWE-based adaptive KF with gain correction (RWE-AKFG), AMA- and RWE- based dual mode adaptive KF (AMA-RWE-DMAKF). Results of Allan variance on static signal and root mean square error (RMSE) on dynamic signal show that this proposed algorithm outperforms all the considered methods in denoising FOG signal.

Thermal effects of an ICL-based mid-infrared CH 4 sensor within a wide atmospheric temperature range

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ye, Weilin; Zheng, Chuantao; Sanchez, Nancy P.

Here, thermal effects of an interband cascade laser (ICL) based mid-infrared methane (CH 4) sensor that uses long-path absorption spectroscopy were studied. The sensor performance in the laboratory at a constant temperature of ~ 25°C was measured for 5 hours and its Allan deviation was ~ 2 ppbv with a 1 s averaging time. A LabVIEW-based simulation program was developed to study thermal effects on infrared absorption and a temperature compensation technique was developed to control such effects. An environmental test chamber was employed to investigate thermal effects that occur in the sensor system with variation of the test chambermore » temperature between 10 and 30°C. The thermal response of the sensor in a laboratory setting was observed using a 2.1 ppm CH 4 standard gas sample. indoor/outdoor CH 4 measurements were conducted to evaluate the sensor performance within a wide atmospheric temperature range.« less

A wide-band fiber optic frequency distribution system employing thermally controlled phase compensation

NASA Technical Reports Server (NTRS)

Johnson, Dean; Calhoun, Malcolm; Sydnor, Richard; Lutes, George

1993-01-01

An active wide-band fiber optic frequency distribution system employing a thermally controlled phase compensator to stabilize phase variations induced by environmental temperature changes is described. The distribution system utilizes bidirectional dual wavelength transmission to provide optical feedback of induced phase variations of 100 MHz signals propagating along the distribution cable. The phase compensation considered differs from earlier narrow-band phase compensation designs in that it uses a thermally controlled fiber delay coil rather than a VCO or phase modulation to compensate for induced phase variations. Two advantages of the wide-band system over earlier designs are (1) that it provides phase compensation for all transmitted frequencies, and (2) the compensation is applied after the optical interface rather than electronically ahead of it as in earlier schemes. Experimental results on the first prototype shows that the thermal stabilizer reduces phase variations and Allan deviation by a factor of forty over an equivalent uncompensated fiber optic distribution system.

Chip Scale Atomic Resonator Frequency Stabilization System With Ultra-Low Power Consumption for Optoelectronic Oscillators.

PubMed

Zhao, Jianye; Zhang, Yaolin; Lu, Haoyuan; Hou, Dong; Zhang, Shuangyou; Wang, Zhong

2016-07-01

We present a long-term chip scale stabilization scheme for optoelectronic oscillators (OEOs) based on a rubidium coherent population trapping (CPT) atomic resonator. By locking a single mode of an OEO to the (85)Rb 3.035-GHz CPT resonance utilizing an improved phase-locked loop (PLL) with a PID regulator, we achieved a chip scale frequency stabilization system for the OEO. The fractional frequency stability of the stabilized OEO by overlapping Allan deviation reaches 6.2 ×10(-11) (1 s) and  ∼ 1.45 ×10 (-11) (1000 s). This scheme avoids a decrease in the extra phase noise performance induced by the electronic connection between the OEO and the microwave reference in common injection locking schemes. The total physical package of the stabilization system is [Formula: see text] and the total power consumption is 400 mW, which provides a chip scale and portable frequency stabilization approach with ultra-low power consumption for OEOs.

On Dreams and Motivation: Comparison of Freud's and Hobson's Views.

PubMed

Boag, Simon

2016-01-01

The merits of Freudian dream theory continue to be debated and both supporters and critics appeal to empirical evidence to support their respective positions. What receives much less attention is the theoretical coherency of either Freudian dream theory or alternative perspectives. This paper examines Freudian dream theory and J. Allan Hobson's alternative position by addressing the role of motivation in dreams. This paper first discusses motivation in Freudian theory and its relation to dreams and disguise-censorship. The role of motivation in Hobson's theory is then considered. Hobson's claim that dream plot and content selection is random and based on design error and functional imbalance is then discussed in relation to the protoconsciousness theory proposal that dreams serve an adaptive function. While there are apparent inconsistencies in Hobson's position, his appeal to emotions and instincts provides a preliminary platform for understanding the role of motivation in dreams that is consonant with the Freudian position.

Laser frequency stabilization by combining modulation transfer and frequency modulation spectroscopy.

PubMed

Zi, Fei; Wu, Xuejian; Zhong, Weicheng; Parker, Richard H; Yu, Chenghui; Budker, Simon; Lu, Xuanhui; Müller, Holger

2017-04-01

We present a hybrid laser frequency stabilization method combining modulation transfer spectroscopy (MTS) and frequency modulation spectroscopy (FMS) for the cesium D₂ transition. In a typical pump-probe setup, the error signal is a combination of the DC-coupled MTS error signal and the AC-coupled FMS error signal. This combines the long-term stability of the former with the high signal-to-noise ratio of the latter. In addition, we enhance the long-term frequency stability with laser intensity stabilization. By measuring the frequency difference between two independent hybrid spectroscopies, we investigate the short-and long-term stability. We find a long-term stability of 7.8 kHz characterized by a standard deviation of the beating frequency drift over the course of 10 h and a short-term stability of 1.9 kHz characterized by an Allan deviation of that at 2 s of integration time.

A CO trace gas detection system based on continuous wave DFB-QCL

NASA Astrophysics Data System (ADS)

Dang, Jingmin; Yu, Haiye; Sun, Yujing; Wang, Yiding

2017-05-01

A compact and mobile system was demonstrated for the detection of carbon monoxide (CO) at trace level. This system adopted a high-power, continuous wave (CW), distributed feedback quantum cascade laser (DFB-QCL) operating at ∼22 °C as excitation source. Wavelength modulation spectroscopy (WMS) as well as second harmonic detection was used to isolate complex, overlapping spectral absorption features typical of ambient pressures and to achieve excellent specificity and high detection sensitivity. For the selected P(11) absorption line of CO molecule, located at 2099.083 cm-1, a limit of detection (LoD) of 26 ppb by volume (ppbv) at atmospheric pressure was achieved with a 1 s acquisition time. Allan deviation analysis was performed to investigate the long term performance of the CO detection system, and a measurement precision of 3.4 ppbv was observed with an optimal integration time of approximate 114 s, which verified the reliable and robust operation of the developed system.

The experimenters' regress reconsidered: Replication, tacit knowledge, and the dynamics of knowledge generation.

PubMed

Feest, Uljana

2016-08-01

This paper revisits the debate between Harry Collins and Allan Franklin, concerning the experimenters' regress. Focusing my attention on a case study from recent psychology (regarding experimental evidence for the existence of a Mozart Effect), I argue that Franklin is right to highlight the role of epistemological strategies in scientific practice, but that his account does not sufficiently appreciate Collins's point about the importance of tacit knowledge in experimental practice. In turn, Collins rightly highlights the epistemic uncertainty (and skepticism) surrounding much experimental research. However, I will argue that his analysis of tacit knowledge fails to elucidate the reasons why scientists often are (and should be) skeptical of other researchers' experimental results. I will present an analysis of tacit knowledge in experimental research that not only answers to this desideratum, but also shows how such skepticism can in fact be a vital enabling factor for the dynamic processes of experimental knowledge generation. Copyright © 2016 Elsevier Ltd. All rights reserved.

On-orbit frequency stability analysis of the GPS NAVSTAR-1 quartz clock and the NAVSTARs-6 and -8 rubidium clocks

NASA Technical Reports Server (NTRS)

Mccaskill, T. B.; Buisson, J. A.; Reid, W. G.

1984-01-01

An on-orbit frequency stability performance analysis of the GPS NAVSTAR-1 quartz clock and the NAVSTARs-6 and -8 rubidium clocks is presented. The clock offsets were obtained from measurements taken at the GPS monitor stations which use high performance cesium standards as a reference. Clock performance is characterized through the use of the Allan variance, which is evaluated for sample times of 15 minutes to two hours, and from one day to 10 days. The quartz and rubidium clocks' offsets were corrected for aging rate before computing the frequency stability. The effect of small errors in aging rate is presented for the NAVSTAR-8 rubidium clock's stability analysis. The analysis includes presentation of time and frequency residuals with respect to linear and quadratic models, which aid in obtaining aging rate values and identifying systematic and random effects. The frequency stability values were further processed with a time domain noise process analysis, which is used to classify random noise process and modulation type.

Social Work Field Training for the Community: A Student Self-Directed Approach in the Environmental Domain in Jordan

PubMed Central

Al-Makhamreh, Sahar; Alnabulsi, Hana; Asfour, Hana

2016-01-01

This article outlines innovative field training methods that foster the abilities of undergraduate social work students so that they are able to empower the local community and raise awareness of environmental issues. In this study, students were engaged in a local community assessment that sought to understand their views on environmental and community impacts of the Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME) Project on the lives of the host village's residents. A students' self-directed approach was applied for the fieldwork out of which interventions were developed ( Garrison, 1997). Quantitative data were gathered by eighteen students through a survey of 361 questionnaires targeting Allan society. In addition to students' field notes, pre and post focus groups were used to collect qualitative information. Study findings highlighted the effectiveness of students' self-directed projects in cultivating culturally competent practices; ensuring sustainable development; and providing evidence-based knowledge on social work practice involving environmental issues. PMID:27559202

Social Work Field Training for the Community: A Student Self-Directed Approach in the Environmental Domain in Jordan.

PubMed

Al-Makhamreh, Sahar; Alnabulsi, Hana; Asfour, Hana

2016-06-01

This article outlines innovative field training methods that foster the abilities of undergraduate social work students so that they are able to empower the local community and raise awareness of environmental issues. In this study, students were engaged in a local community assessment that sought to understand their views on environmental and community impacts of the Synchrotron-Light for Experimental Science and Applications in the Middle East (SESAME) Project on the lives of the host village's residents. A students' self-directed approach was applied for the fieldwork out of which interventions were developed ( Garrison, 1997). Quantitative data were gathered by eighteen students through a survey of 361 questionnaires targeting Allan society. In addition to students' field notes, pre and post focus groups were used to collect qualitative information. Study findings highlighted the effectiveness of students' self-directed projects in cultivating culturally competent practices; ensuring sustainable development; and providing evidence-based knowledge on social work practice involving environmental issues.

Hand-Writing Motion Tracking with Vision-Inertial Sensor Fusion: Calibration and Error Correction

PubMed Central

Zhou, Shengli; Fei, Fei; Zhang, Guanglie; Liu, Yunhui; Li, Wen J.

2014-01-01

The purpose of this study was to improve the accuracy of real-time ego-motion tracking through inertial sensor and vision sensor fusion. Due to low sampling rates supported by web-based vision sensor and accumulation of errors in inertial sensors, ego-motion tracking with vision sensors is commonly afflicted by slow updating rates, while motion tracking with inertial sensor suffers from rapid deterioration in accuracy with time. This paper starts with a discussion of developed algorithms for calibrating two relative rotations of the system using only one reference image. Next, stochastic noises associated with the inertial sensor are identified using Allan Variance analysis, and modeled according to their characteristics. Finally, the proposed models are incorporated into an extended Kalman filter for inertial sensor and vision sensor fusion. Compared with results from conventional sensor fusion models, we have shown that ego-motion tracking can be greatly enhanced using the proposed error correction model. PMID:25157546

Compact CH{sub 4} sensor system based on a continuous-wave, low power consumption, room temperature interband cascade laser

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Lei, E-mail: donglei@sxu.edu.cn; State Key Laboratory of Quantum Optics and Quantum Optics Devices, Institute of Laser Spectroscopy, Shanxi University, Taiyuan 030006; Li, Chunguang

A tunable diode laser absorption spectroscopy-based methane sensor, employing a dense-pattern multi-pass gas cell and a 3.3 μm, CW, DFB, room temperature interband cascade laser (ICL), is reported. The optical integration based on an advanced folded optical path design and an efficient ICL control system with appropriate electrical power management resulted in a CH{sub 4} sensor with a small footprint (32 × 20 × 17 cm{sup 3}) and low-power consumption (6 W). Polynomial and least-squares fit algorithms are employed to remove the baseline of the spectral scan and retrieve CH{sub 4} concentrations, respectively. An Allan-Werle deviation analysis shows that the measurement precision can reach 1.4 ppb for amore » 60 s averaging time. Continuous measurements covering a seven-day period were performed to demonstrate the stability and robustness of the reported CH{sub 4} sensor system.« less

Few-femtosecond-resolution characterization and suppression of excess timing jitter and drift in indoor atmospheric frequency comb transfer.

PubMed

Kang, Jinho; Shin, Junho; Kim, Chur; Jung, Kwangyun; Park, Suhyeon; Kim, Jungwon

2014-10-20

We characterize the timing jitter spectral density of the time-of-flight (TOF) in the indoor atmospheric transfer of optical pulse train over 10 decades of Fourier frequency range (10 μHz - 100 kHz) with sub-100-as resolution using a balanced optical cross-correlator (BOC). Based on the well-known theory for atmospheric transfer of a laser beam, we could fit the measured timing jitter power spectral density to the theory and analyze it with a fairly good agreement from 20 mHz to 10 Hz Fourier frequency range. Moreover, we demonstrate that the BOC-based timing stabilization method can suppress the excess fluctuations in timing from >200 fs (rms) to 2.6 fs (rms) maintained over 130 hours when an optical pulse train is transferred over a 76.2-m long free-space beam path in laboratory environment. The demonstrated stabilization result corresponds to 4 × 10(-20) overlapping Allan deviation at 117,000 s averaging time.

The effect of aperture averaging upon tropospheric delay fluctuations seen with a DSN antenna

NASA Technical Reports Server (NTRS)

Linfield, R.

1996-01-01

The spectrum of tropospheric delay fluctuations expected for a DSN antenna at time scales less than 100 s has been calculated. A new feature included in these calculations is the effect of aperture averaging, which causes a reduction in delay fluctuations on time scales less than the antenna wind speed crossing time, approximately equal to 5-10 s. On time scales less than a few seconds, the Allan deviation sigma(sub y)(Delta(t)) varies as (Delta(t))(sup +1), rather than sigma(sub y)(Delta(t)) varies as (Delta(t))(exp -1/6) without aperture averaging. Due to thermal radiometer noise, calibration of tropospheric delay fluctuations with water vapor radiometers will not be possible on time scales less than approximately 10 s. However, the tropospheric fluctuation level will be small enough that radio science measurements with a spacecraft on time scales less than a few seconds will be limited by the stability of frequency standards and/or other nontropospheric effects.

Thermal effects of an ICL-based mid-infrared CH 4 sensor within a wide atmospheric temperature range

DOE PAGES

Ye, Weilin; Zheng, Chuantao; Sanchez, Nancy P.; ...

2018-01-31

Here, thermal effects of an interband cascade laser (ICL) based mid-infrared methane (CH 4) sensor that uses long-path absorption spectroscopy were studied. The sensor performance in the laboratory at a constant temperature of ~ 25°C was measured for 5 hours and its Allan deviation was ~ 2 ppbv with a 1 s averaging time. A LabVIEW-based simulation program was developed to study thermal effects on infrared absorption and a temperature compensation technique was developed to control such effects. An environmental test chamber was employed to investigate thermal effects that occur in the sensor system with variation of the test chambermore » temperature between 10 and 30°C. The thermal response of the sensor in a laboratory setting was observed using a 2.1 ppm CH 4 standard gas sample. indoor/outdoor CH 4 measurements were conducted to evaluate the sensor performance within a wide atmospheric temperature range.« less

[Absorption spectrum of Quasi-continuous laser modulation demodulation method].

PubMed

Shao, Xin; Liu, Fu-Gui; Du, Zhen-Hui; Wang, Wei

2014-05-01

A software phase-locked amplifier demodulation method is proposed in order to demodulate the second harmonic (2f) signal of quasi-continuous laser wavelength modulation spectroscopy (WMS) properly, based on the analysis of its signal characteristics. By judging the effectiveness of the measurement data, filter, phase-sensitive detection, digital filtering and other processing, the method can achieve the sensitive detection of quasi-continuous signal The method was verified by using carbon dioxide detection experiments. The WMS-2f signal obtained by the software phase-locked amplifier and the high-performance phase-locked amplifier (SR844) were compared simultaneously. The results show that the Allan variance of WMS-2f signal demodulated by the software phase-locked amplifier is one order of magnitude smaller than that demodulated by SR844, corresponding two order of magnitude lower of detection limit. And it is able to solve the unlocked problem caused by the small duty cycle of quasi-continuous modulation signal, with a small signal waveform distortion.

Radio-science performance analysis software

NASA Technical Reports Server (NTRS)

Morabito, D. D.; Asmar, S. W.

1995-01-01

The Radio Science Systems Group (RSSG) provides various support functions for several flight project radio-science teams. Among these support functions are uplink and sequence planning, real-time operations monitoring and support, data validation, archiving and distribution functions, and data processing and analysis. This article describes the support functions that encompass radio-science data performance analysis. The primary tool used by the RSSG to fulfill this support function is the STBLTY program set. STBLTY is used to reconstruct observable frequencies and calculate model frequencies, frequency residuals, frequency stability in terms of Allan deviation, reconstructed phase, frequency and phase power spectral density, and frequency drift rates. In the case of one-way data, using an ultrastable oscillator (USO) as a frequency reference, the program set computes the spacecraft transmitted frequency and maintains a database containing the in-flight history of the USO measurements. The program set also produces graphical displays. Some examples and discussions on operating the program set on Galileo and Ulysses data will be presented.

Synthetic Sediments and Stochastic Groundwater Hydrology

NASA Astrophysics Data System (ADS)

Wilson, J. L.

2002-12-01

For over twenty years the groundwater community has pursued the somewhat elusive goal of describing the effects of aquifer heterogeneity on subsurface flow and chemical transport. While small perturbation stochastic moment methods have significantly advanced theoretical understanding, why is it that stochastic applications use instead simulations of flow and transport through multiple realizations of synthetic geology? Allan Gutjahr was a principle proponent of the Fast Fourier Transform method for the synthetic generation of aquifer properties and recently explored new, more geologically sound, synthetic methods based on multi-scale Markov random fields. Focusing on sedimentary aquifers, how has the state-of-the-art of synthetic generation changed and what new developments can be expected, for example, to deal with issues like conceptual model uncertainty, the differences between measurement and modeling scales, and subgrid scale variability? What will it take to get stochastic methods, whether based on moments, multiple realizations, or some other approach, into widespread application?

Focus issue introduction: nonlinear photonics.

PubMed

Akhmediev, Nail; Rottwitt, Karsten

2012-11-19

It is now 23 years since the first Topical Meeting "Nonlinear Guided Wave Phenomena" (Houston, TX, February 2-4, 1989) has been organised by George Stegeman and Allan Boardman with support of the Optical Society of America. These series of the OSA conferences known as NLGW, continued under the name "Nonlinear Photonics" starting from 2007. The latest one, in Colorado Springs in June 17-21, 2012 has been a great success despite the fierce fires advancing around the city at the time of the conference. This Focus issue is a collection of several papers presented at the conference with extended content submitted to Optics Express. Although this collection is small in comparison to the total number of papers presented at the conference, it gives a flavor of the topics considered at the meeting. It is also worthy to mention here that the next meeting "Nonlinear Photonics" is planned to be held in Barcelona - one of the main European centers on this subject.

The Natural Thermoluminescence Survey of Antarctic Meteorites: Ordinary Chondrites at the Grosvenor Mountains, Macalpine Hills, Pecora Escarpment and Queen Alexandra Range, and New Data for the Elephant Moraine, Ice Fields

NASA Technical Reports Server (NTRS)

Benoit, Paul H.; Sears, Derek W. G.

1999-01-01

The natural TL (Thermoluminescence) survey of Antarctic meteorites was started in 1987 at the request of the Antarctic Meteorite Working Group in order to provide an initial description of radiation and thermal histories. It was intended to be a complement to the mineralogical and petrographic surveys performed at the Johnson Space Center and the Smithsonian Institution. All ANSMET (Antarctic Search for Meteorites) samples recovered since then, besides those that were heated throughout by atmospheric passage, have been measured. To date this amounts to about 1200 samples. As the data for each ice field reaches a significant level, we have been conducting a thorough examination of the data for that field with a view to identifying pairing, providing an estimate of terrestrial age and residence time on the ice surface, looking for differences in natural TL between ice fields, looking for variations in natural TL level with location on the ice, looking for meteorites with natural TL levels outside the normal range. Pairing is a necessary first step in ensuring the most productive use of the collection, while geographical variations could perhaps provide clues to concentration mechanisms. Samples with natural TL values outside the normal range are usually inferred to have had either small perihelia or recent changes in orbital elements. In addition, induced TL data have enabled us to look for evidence for secular variation in the nature of the flux of meteorites to Earth, and look for petrologically unusual meteorites, such as particularly primitive ordinary chondrites, heavily shocked meteorites, or otherwise anomalous meteorites. To date we have published studies of the TL properties of 167 ordinary chondrites from Allan Hills, 107 from Elephant Moraine and 302 from Lewis Cliff and we have discussed the TL properties of fifteen H chondrites collected at the Allan Hills by Euromet after a storm during the 1988 season. We now have additional databases for a reasonable

The Natural Thermoluminescence Survey of Antarctic Meteorites: Ordinary Chondrites at the Grosvenor Mountains, MacAlpine Hills, Pecora Escarpment and Queen Alexandra Range, and New Data New Data for the Elephant Moraine, Ice Fields

NASA Technical Reports Server (NTRS)

Benoit, Paul H.; Sears, Derek W. G.

2000-01-01

The natural TL survey of Antarctic meteorites was started in 1987 at the request of the Antarctic Meteorite Working Group in order to provide an initial description of radiation and thermal histories. It was intended to be a complement to the mineralogical and petrographic surveys performed at the Johnson Space Center and the Smithsonian Institution. All ANSMET samples recovered since then, besides those that were heated throughout by atmospheric passage, have been measured. To date this amounts to about 1200 samples. As the data for each ice field reaches a significant level, we have been conducting a thorough examination of the data for that field with a view to (1) identifying pairing, (2) providing an estimate of terrestrial age and residence time on the ice surface, (3) looking for differences in natural TL between ice fields, (4) looking for variations in natural TL level with location on the ice, (5) looking for meteorites with natural TL levels outside the normal range. Pairing is a necessary first step in ensuring the @ost productive use of the collection, while geographical variations could perhaps provide clues to concentration mechanisms. Samples with natural TL values outside the normal range are usually inferred to have had either small perihelia or recent changes in orbital elements. In addition, induced TL data have enabled us to (5) look for evidence for secular variation in the nature of the flux of meteorites to Earth, and (6) look for petrologically unusual meteorites, such as particularly primitive ordinary chondrites, heavily shocked meteorites, or otherwise anomalous meteorites. To date we have published studies of the TL properties of 167 ordinary chondrites from Allan Hills, 107 from Elephant Moraine and 302 from Lewis Cliff and we have discussed the TL properties of fifteen H chondrites collected at the Allan Hills by Euromet after a storm during the 1988 season. We now have additional databases for a reasonable number of ordinary

Noise performance of microwave humidity sounders over their lifetime

NASA Astrophysics Data System (ADS)

Hans, Imke; Burgdorf, Martin; John, Viju O.; Mittaz, Jonathan; Buehler, Stefan A.

2017-12-01

The microwave humidity sounders Special Sensor Microwave Water Vapor Profiler (SSMT-2), Advanced Microwave Sounding Unit-B (AMSU-B) and Microwave Humidity Sounder (MHS) to date have been providing data records for 25 years. So far, the data records lack uncertainty information essential for constructing consistent long time data series. In this study, we assess the quality of the recorded data with respect to the uncertainty caused by noise. We calculate the noise on the raw calibration counts from the deep space views (DSVs) of the instrument and the noise equivalent differential temperature (NEΔT) as a measure for the radiometer sensitivity. For this purpose, we use the Allan deviation that is not biased from an underlying varying mean of the data and that has been suggested only recently for application in atmospheric remote sensing. Moreover, we use the bias function related to the Allan deviation to infer the underlying spectrum of the noise. As examples, we investigate the noise spectrum in flight for some instruments. For the assessment of the noise evolution in time, we provide a descriptive and graphical overview of the calculated NEΔT over the life span of each instrument and channel. This overview can serve as an easily accessible information for users interested in the noise performance of a specific instrument, channel and time. Within the time evolution of the noise, we identify periods of instrumental degradation, which manifest themselves in an increasing NEΔT, and periods of erratic behaviour, which show sudden increases of NEΔT interrupting the overall smooth evolution of the noise. From this assessment and subsequent exclusion of the aforementioned periods, we present a chart showing available data records with NEΔT < 1 K. Due to overlapping life spans of the instruments, these reduced data records still cover without gaps the time since 1994 and may therefore serve as a first step for constructing long time series. Our method for count

Marine magnetic survey between Cabo da Roca and Cabo Espichel (near Lisbon, Portugal): first results

NASA Astrophysics Data System (ADS)

Neres, Marta; Terrinha, Pedro; Calado, António; Miranda, Miguel; Madureira, Pedro

2016-04-01

We present a magnetic survey conducted in the offshore region between Cabo da Roca and Sesimbra (mouth of Tagus River, Portugal). Strong magnetic anomalies are recognized in this area since a first marine survey in 1958 (Allan, 1965) and by further aeromagnetic survey (c.f. Silva et al, 2000). The anomalies have been linked to Cretaceous magmatic events related to the Upper Cretaceous Sintra magmatic complex and Lisbon volcanic complex, but their geometry and extension has yet not been resolved. The aim of the present survey was to unravel the location, geometry and type of the magnetic sources, thus contributing for the characterization of the main magmatic and tectonic features in the region. The survey was conducted in two legs (October 2014 and June 2015), consisting of 27 lines and 6 tielines, extending up to 40 km from the coast. The line spacing was 1 mile for the main lines and 5-6 miles for the tielines. The bathymetry of the surveyed area varies from very shallow (about 10 m) to near 3000 m. Total field was measured with a G-882 Cesium marine magnetometer of Geometrics (self-oscillating split-beam Cesium vapor), with frequency of acquisition of 10 Hz. Layback was real-time corrected using the acquisition software. Noise was removed by despike in Magpick software (Geometrics), and further processing was done using Oasis montaj (Geosoft) software. Data were subtracted of IGRF values and levelled by tielines to retrieve the final map of anomalies. Several punctual and linear anomalies with varying amplitude and wavenumber were identified, which cannot be explained by bathymetric variation; therefore they must then be due to the presence of higher susceptibility, likely volcanic rocks, and to structural inheritance associated with rifting and Alpine orogeny. The highest anomaly corresponds to the Cabo Raso positive magnetic anomaly, with maximum and minimum of 2800 nT and -1350 nT, respectively. This anomaly, already surveyed in 1958, has been compared to a

PREFACE: Symmetries in Science XVI

NASA Astrophysics Data System (ADS)

2014-10-01

This volume of the proceedings ''Symmetries in Science XVI'' is dedicated to the memory of Miguel Lorente and Allan Solomon who both participated several times in these Symposia. We lost not only two great scientists and colleagues, but also two wonderful persons of high esteem whom we will always remember. Dieter Schuch, Michael Ramek There is a German saying ''all good things come in threes'' and ''Symmetries in Science XVI'', convened July 20-26, 2013 at the Mehrerau Monastery, was our third in the sequel of these symposia since taking it over from founder Bruno Gruber who instigated it in 1988 (then in Lochau). Not only the time seemed to have been perfect (one week of beautiful sunshine), but also the medley of participants could hardly have been better. This time, 34 scientists from 16 countries (more than half outside the European Union) came together to report and discuss their latest results in various fields of science, all related to symmetries. The now customary grouping of renowned experts and talented newcomers was very rewarding and stimulating for all. The informal, yet intense, discussions at ''Gasthof Lamm'' occurred (progressively later) each evening till well after midnight and finally till almost daybreak! However, prior to the opening ceremony and during the conference, respectively, we were informed that Miguel Lorente and Allan Solomon had recently passed away. Both attended the SIS Symposia several times and had many friends among present and former participants. Professor Peter Kramer, himself a long-standing participant and whose 80th birthday commemoration prevented him from attending SIS XVI, kindly agreed to write the obituary for Miguel Lorente. Professors Richard Kerner and Carol Penson (both also former attendees) penned, at very short notice, the tribute to Allan Solomon. The obituaries are included in these Proceedings and further tributes have been posted to our conference website. In 28 lectures and an evening poster

The Chemical Chaperone Phenylbutyrate Rescues MCT8 Mutations Associated With Milder Phenotypes in Patients With Allan-Herndon-Dudley Syndrome.

PubMed

Braun, Doreen; Schweizer, Ulrich

2017-03-01

Mutations in the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) prevent appropriate entry of thyroid hormones into brain cells during development and cause severe mental retardation in affected patients. The current treatment options are thyromimetic compounds that enter the brain independently of MCT8. Some MCT8-deficient patients (e.g., those carrying MCT8delF501) will not be as severely affected as most others. We have shown that the MCT8delF501 protein has decreased protein stability but important residual function once it reaches the plasma membrane. We were able to rescue protein expression and the function of MCT8delF501 in a Madin-Darby canine kidney cell model by application of the chemical chaperone sodium phenylbutyrate (NaPB), a drug that has been used to treat patients with cystic fibrosis and urea cycle defects for extended periods of time. In the present study, we have extended our previous study and report on the NaPB-dependent rescue of a series of other pathogenic MCT8 mutants associated with milder patient phenotypes. We show that NaPB can functionally rescue the expression and activities of Ser194Phe, Ser290Phe, Leu434Trp, Arg445Cys, Leu492Pro, and Leu568Pro mutations in MCT8 in a dose-dependent manner. The soy isoflavone genistein, a dietary supplement, which was effective in MCT8delF501, was also effective in increasing the expression and transport of these MCT8 mutants; however, the effect size differed among mutants. Kinetic analyses revealed that the Michaelis constants of the mutants toward the primary substrate 3,3',5-triiodothyronine were not much different from the wild-type value, suggesting that these mutants are not impaired in their interaction with substrate but rather destabilized by the mutation and degraded. Copyright © 2017 by the Endocrine Society.

The flight performance of the Galileo orbiter USO

NASA Technical Reports Server (NTRS)

Morabito, D. D.; Krisher, T. P.; Asmar, S. W.

1993-01-01

Results are presented from an analysis of radio metric data received by the DSN stations from the Galileo spacecraft using an Ultrastable Oscillator (USO) as a signal source. These results allow the health and performance of the Galileo USO to be evaluated, and are used to calibrate this Radio Science instrument and the data acquired for Radio Science experiments such as the Red-shift Observation, Solar Conjunction, and Jovian occultations. Estimates for the USO-referenced spacecraft-transmitted frequency and frequency stability were made for 82 data acquisition passes conducted between launch (October 1989) and November 1991. Analyses of the spacecraft-transmitted frequencies show that the USO is behaving as expected. The USO was powered off and then back on in August 1991 with no adverse effect on its performance. The frequency stabilities measured by Allan deviation are consistent with expected values due to thermal wideband noise and the USO itself at the appropriate time intervals. The Galileo USO appears to be healthy and functioning normally in a reasonable manner.

The flight performance of the Galileo orbiter USO

NASA Technical Reports Server (NTRS)

Morabito, D. D.; Krisher, T. P.; Asmar, S. W.

1993-01-01

Results are presented in this article from an analysis of radio metric data received by the DSN stations from the Galileo spacecraft using an Ultrastable Oscillator (USO) as a signal source. These results allow the health and performance of the Galileo USO to be evaluated, and are used to calibrate this Radio Science instrument and the data acquired for Radio Science experiments such as the Redshift Observation, Solar Conjunction, and Jovian occultations. Estimates for the USO-referenced, spacecraft-transmitted frequency and frequency stability were made for 82 data acquisition passes conducted between launch (Oct. 1989) and Nov. 1991. Analyses of the spacecraft-transmitted frequencies show that the USO is behaving as expected. The USO was powered off and then back on in Aug. 1991 with no adverse effect on its performance. The frequency stabilities measured by Allan deviation are consistent with expected values due to thermal wideband noise and the USO itself at the appropriate time intervals. The Galileo USO appears to be healthy and functioning normally in a reasonable manner.

Visualization portal for genetic variation (VizGVar): a tool for interactive visualization of SNPs and somatic mutations in exons, genes and protein domains.

PubMed

Solano-Román, Antonio; Alfaro-Arias, Verónica; Cruz-Castillo, Carlos; Orozco-Solano, Allan

2018-03-15

VizGVar was designed to meet the growing need of the research community for improved genomic and proteomic data viewers that benefit from better information visualization. We implemented a new information architecture and applied user centered design principles to provide a new improved way of visualizing genetic information and protein data related to human disease. VizGVar connects the entire database of Ensembl protein motifs, domains, genes and exons with annotated SNPs and somatic variations from PharmGKB and COSMIC. VizGVar precisely represents genetic variations and their respective location by colored curves to designate different types of variations. The structured hierarchy of biological data is reflected in aggregated patterns through different levels, integrating several layers of information at once. VizGVar provides a new interactive, web-based JavaScript visualization of somatic mutations and protein variation, enabling fast and easy discovery of clinically relevant variation patterns. VizGVar is accessible at http://vizport.io/vizgvar; http://vizport.io/vizgvar/doc/. asolano@broadinstitute.org or allan.orozcosolano@ucr.ac.cr.

CO and CO2 dual-gas detection based on mid-infrared wideband absorption spectroscopy

NASA Astrophysics Data System (ADS)

Dong, Ming; Zhong, Guo-qiang; Miao, Shu-zhuo; Zheng, Chuan-tao; Wang, Yi-ding

2018-03-01

A dual-gas sensor system is developed for CO and CO2 detection using a single broadband light source, pyroelectric detectors and time-division multiplexing (TDM) technique. A stepper motor based rotating system and a single-reflection spherical optical mirror are designed and adopted for realizing and enhancing dual-gas detection. Detailed measurements under static detection mode (without rotation) and dynamic mode (with rotation) are performed to study the performance of the sensor system for the two gas samples. The detection period is 7.9 s in one round of detection by scanning the two detectors. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 3.0 parts per million (ppm) in volume and 2.6 ppm for CO and CO2, respectively, and those under dynamic operation are 9.4 ppm and 10.8 ppm for CO and CO2, respectively. The reported sensor has potential applications in various fields requiring CO and CO2 detection such as in the coal mine.

Topiramate-induced weight loss in schizophrenia: a retrospective case series study.

PubMed

Lévy, Emmanuel; Agbokou, Catherine; Ferreri, Florian; Chouinard, Guy; Margolese, Howard C

2007-01-01

Atypical antipsychotics have been associated with weight gain. This study examines the efficacy of adjunctive topiramate in patients with schizophrenia and schizoaffective disorder with antipsychotic-induced weight gain. A 2-year retrospective case analysis was performed in all 300 patients of the outpatient Special Follow-up Clinic for chronic schizophrenia and related psychoses at the Allan Memorial Institute, McGill University Health Centre (Montreal, Canada), a tertiary care University teaching hospital. 10 patients met study inclusion criteria. Mean daily topiramate dose was 197.5 mg (A+/-77) (range, 125-400 mg). Topiramate produced continued weight loss throughout the study duration without tolerance. Patients treated for 6 months and more had significantly higher Body Mass Index (BMI) differences than those treated for shorter durations (BMI-d6 months=-4.7A+/-2.4; BMI-d2 months=-3.2A+/-2.3; P=0.015). BMI changes were similar across genders. This study supports topiramate use to target weight loss in stable overweight schizophrenic patients as a potential therapy that requires further investigation.

A ppb level sensitive sensor for atmospheric methane detection

NASA Astrophysics Data System (ADS)

Xia, Jinbao; Zhu, Feng; Zhang, Sasa; Kolomenskii, Alexandre; Schuessler, Hans

2017-11-01

A high sensitivity sensor, combining a multipass cell and wavelength modulation spectroscopy in the near infrared spectral region was designed and implemented for trace gas detection. The effective length of the multipass cell was about 290 meters. The developed spectroscopic technique demonstrates an improved sensitivity of methane in ambient air and a relatively short detection time compared to previously reported sensors. Home-built electronics and software were employed for diode laser frequency modulation, signal lock-in detection and processing. A dual beam scheme and a balanced photo-detector were implemented to suppress the intensity modulation and noise for better detection sensitivity. The performance of the sensor was evaluated in a series of measurements ranging from three hours to two days. The average methane concentration measured in ambient air was 2.01 ppm with a relative error of ± 2.5%. With Allan deviation analysis, it was found that the methane detection limit of 1.2 ppb was achieved in 650 s. The developed sensor is compact and portable, and thus it is well suited for field measurements of methane and other trace gases.

Using nonlinear methods to quantify changes in infant limb movements and vocalizations.

PubMed

Abney, Drew H; Warlaumont, Anne S; Haussman, Anna; Ross, Jessica M; Wallot, Sebastian

2014-01-01

The pairing of dynamical systems theory and complexity science brings novel concepts and methods to the study of infant motor development. Accordingly, this longitudinal case study presents a new approach to characterizing the dynamics of infant limb and vocalization behaviors. A single infant's vocalizations and limb movements were recorded from 51-days to 305-days of age. On each recording day, accelerometers were placed on all four of the infant's limbs and an audio recorder was worn on the child's chest. Using nonlinear time series analysis methods, such as recurrence quantification analysis and Allan factor, we quantified changes in the stability and multiscale properties of the infant's behaviors across age as well as how these dynamics relate across modalities and effectors. We observed that particular changes in these dynamics preceded or coincided with the onset of various developmental milestones. For example, the largest changes in vocalization dynamics preceded the onset of canonical babbling. The results show that nonlinear analyses can help to understand the functional co-development of different aspects of infant behavior.

2010 Panel on the Biomaterials Grand Challenges

PubMed Central

Reichert, William “Monty”; Ratner, Buddy D.; Anderson, James; Coury, Art; Hoffman, Allan S.; Laurencin, Cato T.; Tirrell, David

2014-01-01

In 2009, the National Academy for Engineering issued the Grand Challenges for Engineering in the 21st Century comprised of 14 technical challenges that must be addressed to build a healthy, profitable, sustainable, and secure global community (http://www.engineeringchallenges.org). Although crucial, none of the NEA Grand Challenges adequately addressed the challenges that face the biomaterials community. In response to the NAE Grand Challenges, Monty Reichert of Duke University organized a panel entitled Grand Challenges in Biomaterials at the at the 2010 Society for Biomaterials Annual Meeting in Seattle. Six members of the National Academies—Buddy Ratner, James Anderson, Allan Hoffman, Art Coury, Cato Laurencin, and David Tirrell—were asked to propose a grand challenge to the audience that, if met, would significantly impact the future of biomaterials and medical devices. Successfully meeting these challenges will speed the 60-plus year transition from commodity, off-the-shelf biomaterials to bioengineered chemistries, and biomaterial devices that will significantly advance our ability to address patient needs and also to create new market opportunities. PMID:21171147

Electronic properties of moire superlattice bands in layered two dimensional materials

NASA Astrophysics Data System (ADS)

Jung, Jeil

2014-03-01

When atomically thin two-dimensional materials are layered they often form incommensurate non-crystalline structures that exhibit long period moiré patterns when examined by scanning probes. In this talk, I will present a theoretical method which can be used to derive an effective Hamiltonian for these twisted van der Waals heterostructures using input from ab initio calculations performed on short-period crystalline structures. I will argue that the effective Hamiltonian can quantitatively describe the electronic properties of these layered systems for arbitrary twist angle and lattice constants. Applying this method to the important cases of graphene on graphene and graphene on hexagonal-boron nitride, I will present a series of experimentally observable quantities that can be extracted from their electronic structure, including their density of states and local density of states as a function of twist angle, and compare with available experiments. Work done in collaboration with Allan MacDonald, Shaffique Adam, Arnaud Raoux, Zhenhua Qiao, and Ashley DaSilva; and supported by the Singapore National Research Foundation Fellowship NRF-NRFF2012-01.

Detection of nitrogen dioxide by CW cavity-enhanced spectroscopy

NASA Astrophysics Data System (ADS)

Jie, Guo; Han, Ye-Xing; Yu, Zhi-Wei; Tang, Huai-Wu

2016-11-01

In the paper, an accurate and sensitive system was used to monitor the ambient atmospheric NO2 concentrations. This system utilizes cavity attenuated phase shift spectroscopy(CAPS), a technology related to cavity ring down spectroscopy(CRDS). Advantages of the CAPS system include such as: (1) cheap and easy to control the light source, (2) high accuracy, and (3) low detection limit. The performance of the CAPS system was evaluated by measuring of the stability and response of the system. The minima ( 0.08 ppb NO2) in the Allan plots show the optimum average time( 100s) for optimum detection performance of the CAPS system. Over a 20-day-long period of the ambient atmospheric NO2 concentrations monitoring, a comparison of the CAPS system with an extremely accurate and precise chemiluminescence-based NOx analyzer showed that the CAPS system was able to reliably and quantitatively measure both large and small fluctuations in the ambient nitrogen dioxide concentration. The experimental results show that the measuring instrument results correlation is 0.95.

AMA- and RWE- Based Adaptive Kalman Filter for Denoising Fiber Optic Gyroscope Drift Signal

PubMed Central

Yang, Gongliu; Liu, Yuanyuan; Li, Ming; Song, Shunguang

2015-01-01

An improved double-factor adaptive Kalman filter called AMA-RWE-DFAKF is proposed to denoise fiber optic gyroscope (FOG) drift signal in both static and dynamic conditions. The first factor is Kalman gain updated by random weighting estimation (RWE) of the covariance matrix of innovation sequence at any time to ensure the lowest noise level of output, but the inertia of KF response increases in dynamic condition. To decrease the inertia, the second factor is the covariance matrix of predicted state vector adjusted by RWE only when discontinuities are detected by adaptive moving average (AMA).The AMA-RWE-DFAKF is applied for denoising FOG static and dynamic signals, its performance is compared with conventional KF (CKF), RWE-based adaptive KF with gain correction (RWE-AKFG), AMA- and RWE- based dual mode adaptive KF (AMA-RWE-DMAKF). Results of Allan variance on static signal and root mean square error (RMSE) on dynamic signal show that this proposed algorithm outperforms all the considered methods in denoising FOG signal. PMID:26512665

Thyroid Hormone Transporters MCT8 and OATP1C1 Control Skeletal Muscle Regeneration.

PubMed

Mayerl, Steffen; Schmidt, Manuel; Doycheva, Denica; Darras, Veerle M; Hüttner, Sören S; Boelen, Anita; Visser, Theo J; Kaether, Christoph; Heuer, Heike; von Maltzahn, Julia

2018-06-05

Thyroid hormone (TH) transporters are required for the transmembrane passage of TH in target cells. In humans, inactivating mutations in the TH transporter MCT8 cause the Allan-Herndon-Dudley syndrome, characterized by severe neuromuscular symptoms and an abnormal TH serum profile, which is fully replicated in Mct8 knockout mice and Mct8/Oatp1c1 double-knockout (M/O DKO) mice. Analysis of tissue TH content and expression of TH-regulated genes indicate a thyrotoxic state in Mct8-deficient skeletal muscles. Both TH transporters are upregulated in activated satellite cells (SCs). In M/O DKO mice, we observed a strongly reduced number of differentiated SCs, suggesting an impaired stem cell function. Moreover, M/O DKO mice and mice lacking both transporters exclusively in SCs showed impaired skeletal muscle regeneration. Our data provide solid evidence for a unique gate-keeper function of MCT8 and OATP1C1 in SC activation, underscoring the importance of a finely tuned TH signaling during myogenesis. Copyright © 2018 The Author(s). Published by Elsevier Inc. All rights reserved.

A compact holographic optical tweezers instrument

NASA Astrophysics Data System (ADS)

Gibson, G. M.; Bowman, R. W.; Linnenberger, A.; Dienerowitz, M.; Phillips, D. B.; Carberry, D. M.; Miles, M. J.; Padgett, M. J.

2012-11-01

Holographic optical tweezers have found many applications including the construction of complex micron-scale 3D structures and the control of tools and probes for position, force, and viscosity measurement. We have developed a compact, stable, holographic optical tweezers instrument which can be easily transported and is compatible with a wide range of microscopy techniques, making it a valuable tool for collaborative research. The instrument measures approximately 30×30×35 cm and is designed around a custom inverted microscope, incorporating a fibre laser operating at 1070 nm. We designed the control software to be easily accessible for the non-specialist, and have further improved its ease of use with a multi-touch iPad interface. A high-speed camera allows multiple trapped objects to be tracked simultaneously. We demonstrate that the compact instrument is stable to 0.5 nm for a 10 s measurement time by plotting the Allan variance of the measured position of a trapped 2 μm silica bead. We also present a range of objects that have been successfully manipulated.

Management and the conservation of freshwater ecosystems

USGS Publications Warehouse

Wipfli, Mark S.; Richardson, John S.

2015-01-01

Riparian and freshwater ecosystems are typically tightly coupled, especially in their natural states, and the linkages that couple them frequently exert strong influence on their associated invertebrate and fish fauna (e.g. Gregory et al., 1991; Naiman et al., 2010). Riparian habitats, and the condition of these habitats, further plays a key role in the ecology of these fresh waters, influencing critical processes such as water, nutrient and sediment delivery and dynamics; prey resources for fish and other consumers, and other organic materials exchanged between aquatic and terrestrial habitats (Nakano et al., 1999; Naiman et al., 2010); light and water temperature dynamics that in turn affect food web processes and fish metabolism and growth; aquatic physical habitat (wood); and terrestrial consumers that prey upon fishes (Bisson & Bilby, 1998; Naiman et al., 2010; Wipfli & Baxter, 2010). These processes in turn directly or indirectly influence fishes in freshwater systems (Wang et al., 2001; Pusey & Arthington, 2003; Allan, 2004; Richardson et al., 2010a).

Ppbv-Level Ethane Detection Using Quartz-Enhanced Photoacoustic Spectroscopy with a Continuous-Wave, Room Temperature Interband Cascade Laser

PubMed Central

Li, Chunguang; Dong, Lei; Zheng, Chuantao; Lin, Jun; Wang, Yiding

2018-01-01

A ppbv-level quartz-enhanced photoacoustic spectroscopy (QEPAS)-based ethane (C2H6) sensor was demonstrated by using a 3.3 μm continuous-wave (CW), distributed feedback (DFB) interband cascade laser (ICL). The ICL was employed for targeting a strong C2H6 absorption line located at 2996.88 cm−1 in its fundamental absorption band. Wavelength modulation spectroscopy (WMS) combined with the second harmonic (2f) detection technique was utilized to increase the signal-to-noise ratio (SNR) and simplify data acquisition and processing. Gas pressure and laser frequency modulation depth were optimized to be 100 Torr and 0.106 cm−1, respectively, for maximizing the 2f signal amplitude. Performance of the QEPAS sensor was evaluated using specially prepared C2H6 samples. A detection limit of 11 parts per billion in volume (ppbv) was obtained with a 1-s integration time based on an Allan-Werle variance analysis, and the detection precision can be further improved to ~1.5 ppbv by increasing the integration time up to 230 s. PMID:29495610

Mid-infrared photoacoustic spectroscopy for atmospheric NO2 measurements

NASA Astrophysics Data System (ADS)

Lassen, Mikael; Lamard, Laurent; Balslev-Harder, David; Peremans, Andre; Petersen, Jan C.

2018-02-01

A photoacoustic (PA) sensor for spectroscopic measurements of NO2-N2 at ambient pressure and temperature is demonstrated. The PA sensor is pumped resonantly by a nanosecond pulsed single-mode mid-infrared (MIR) optical parametric oscillator (OPO). Spectroscopic measurements of NO2-N2 in the 3.25 μm to 3.55 μm wavelength region with a resolution bandwidth of 5 cm-1 and with a single shot detection limit of 1.6 ppmV (μmol/mol) is demonstrated. The measurements were conducted with a constant flow rate of 300 ml/min, thus demonstrating the suitability of the gas sensor for real time trace gas measurements. The acquired spectra is compared with data from the Hitran database and good agreement is found. An Allan deviation analysis shows that the detection limit at optimum integration time for the PAS sensor is 14 ppbV (nmol/mol) at 170 seconds of integration time, corresponding to a normalized noise equivalent absorption (NNEA) coefficient of 3.3×10-7 W cm-1 Hz-1/2.

Using nonlinear methods to quantify changes in infant limb movements and vocalizations

PubMed Central

Abney, Drew H.; Warlaumont, Anne S.; Haussman, Anna; Ross, Jessica M.; Wallot, Sebastian

2014-01-01

The pairing of dynamical systems theory and complexity science brings novel concepts and methods to the study of infant motor development. Accordingly, this longitudinal case study presents a new approach to characterizing the dynamics of infant limb and vocalization behaviors. A single infant's vocalizations and limb movements were recorded from 51-days to 305-days of age. On each recording day, accelerometers were placed on all four of the infant's limbs and an audio recorder was worn on the child's chest. Using nonlinear time series analysis methods, such as recurrence quantification analysis and Allan factor, we quantified changes in the stability and multiscale properties of the infant's behaviors across age as well as how these dynamics relate across modalities and effectors. We observed that particular changes in these dynamics preceded or coincided with the onset of various developmental milestones. For example, the largest changes in vocalization dynamics preceded the onset of canonical babbling. The results show that nonlinear analyses can help to understand the functional co-development of different aspects of infant behavior. PMID:25161629

FOG Random Drift Signal Denoising Based on the Improved AR Model and Modified Sage-Husa Adaptive Kalman Filter.

PubMed

Sun, Jin; Xu, Xiaosu; Liu, Yiting; Zhang, Tao; Li, Yao

2016-07-12

In order to reduce the influence of fiber optic gyroscope (FOG) random drift error on inertial navigation systems, an improved auto regressive (AR) model is put forward in this paper. First, based on real-time observations at each restart of the gyroscope, the model of FOG random drift can be established online. In the improved AR model, the FOG measured signal is employed instead of the zero mean signals. Then, the modified Sage-Husa adaptive Kalman filter (SHAKF) is introduced, which can directly carry out real-time filtering on the FOG signals. Finally, static and dynamic experiments are done to verify the effectiveness. The filtering results are analyzed with Allan variance. The analysis results show that the improved AR model has high fitting accuracy and strong adaptability, and the minimum fitting accuracy of single noise is 93.2%. Based on the improved AR(3) model, the denoising method of SHAKF is more effective than traditional methods, and its effect is better than 30%. The random drift error of FOG is reduced effectively, and the precision of the FOG is improved.

Online technique for detecting state of onboard fiber optic gyroscope

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miao, Zhiyong; He, Kunpeng, E-mail: pengkhe@126.com; Pang, Shuwan

2015-02-15

Although angle random walk (ARW) of fiber optic gyroscope (FOG) has been well modeled and identified before being integrated into the high-accuracy attitude control system of satellite, aging and unexpected failures can affect the performance of FOG after launch, resulting in the variation of ARW coefficient. Therefore, the ARW coefficient can be regarded as an indicator of “state of health” for FOG diagnosis in some sense. The Allan variance method can be used to estimate ARW coefficient of FOG, however, it requires a large amount of data to be stored. Moreover, the procedure of drawing slope lines for estimation ismore » painful. To overcome the barriers, a weighted state-space model that directly models the ARW to obtain a nonlinear state-space model was established for FOG. Then, a neural extended-Kalman filter algorithm was implemented to estimate and track the variation of ARW in real time. The results of experiment show that the proposed approach is valid to detect the state of FOG. Moreover, the proposed technique effectively avoids the storage of data.« less

High T3, Low T4 Serum Levels in Mct8 Deficiency Are Not Caused by Increased Hepatic Conversion through Type I Deiodinase.

PubMed

Wirth, Eva K; Rijntjes, Eddy; Meyer, Franziska; Köhrle, Josef; Schweizer, Ulrich

2015-09-01

The Allan-Herndon-Dudley syndrome is a severe psychomotor retardation accompanied by specific changes in circulating thyroid hormone levels (high T3, low T4). These are caused by mutations in the thyroid hormone transmembrane transport protein monocarboxylate transporter 8 (MCT8). To test the hypothesis that circulating low T4 and high T3 levels are caused by enhanced conversion of T4 via increased activity of hepatic type I deiodinase (Dio1). We crossed mice deficient in Mct8 with mice lacking Dio1 activity in hepatocytes. Translation of the selenoenzyme Dio1 was abrogated by hepatocyte-specific inactivation of selenoprotein biosynthesis. Inactivation of Dio1 activity in the livers of global Mct8-deficient mice does not restore normal circulating thyroid hormone levels. Our data suggest that although hepatic Dio1 activity is increased in Mct8-deficient mice, it does not cause the observed abnormal circulating thyroid hormone levels. Since global inactivation of Dio1 in Mct8-deficient mice does normalize circulating thyroid hormone levels, the underlying mechanism and relevant tissues involved remain to be elucidated.

Complementary rare earth element patterns in unique achondrites, such as ALHA 77005 and shergottites, and in the earth

NASA Technical Reports Server (NTRS)

Ma, M.-S.; Schmitt, R. A.; Laul, J. C.

1982-01-01

Abundances of major, minor, and trace elements are determined in the Antarctic achondrite Allan Hills (ALHA) 77005 via sequential instrumental and radiochemical neutron activation analysis. The rare earth element (REE) abundances of ALHA 77005 reveal a unique chondritic normalized pattern; that is, the REEs are nearly unfractionated from La to Pr at approximately 1.0X chondrites, monotonically increased from Pr to Gd at approximately 3.4X with no Eu anomaly, nearly unfractionated from Gd and Ho and monotonically decreased from Ho to Lu at approximately 2.2X. It is noted that this unique REE pattern of ALHA 77005 can be modeled by a melting process involving a continuous melting and progressive partial removal of melt from a light REE enriched source material. In a model of this type, ALHA 77005 could represent either a crystallized cumulate from such a melt or the residual source material. Calculations show that the parent liquids for the shergottites could also be derived from a light REE enriched source material similar to that for ALHA 77005.

A Latin-cross-shaped integrated resonant cantilever with second torsion-mode resonance for ultra-resoluble bio-mass sensing

NASA Astrophysics Data System (ADS)

Xia, Xiaoyuan; Zhang, Zhixiang; Li, Xinxin

2008-03-01

Second torsion-mode resonance is proposed for microcantilever biosensors for ultra-high mass-weighing sensitivity and resolution. By increasing both the resonant frequency and Q-factor, the higher mode torsional resonance is favorable for improving the mass-sensing performance. For the first time, a Latin-cross-shaped second-mode resonant cantilever is constructed and optimally designed for both signal-readout and resonance-exciting elements. The cantilever sensor is fabricated by using silicon micromachining techniques. The transverse piezoresistive sensing element and the specific-shaped resonance-exciting loop are successfully integrated in the cantilever. Alpha-fetoprotein (AFP) antibody-antigen specific binding is implemented for the sensing experiment. The proposed cantilever sensor is designed with significantly superior sensitivity to the previously reported first torsion-mode one. After analysis with an Allan variance algorithm, which can be easily embedded in the sensing system, the Latin-cross-shaped second torsion-mode resonant cantilever is evaluated with ultra-high mass resolution. Therefore, the high-performance integrated micro-sensor is promising for on-the-spot bio-molecule detection.

Ring Current He Ion Control by Bounce Resonant ULF Waves

NASA Astrophysics Data System (ADS)

Kim, Hyomin; Gerrard, Andrew J.; Lanzerotti, Louis J.; Soto-Chavez, Rualdo; Cohen, Ross J.; Manweiler, Jerry W.

2017-12-01

Ring current energy He ion (˜65 keV to ˜520 keV) differential flux data from the Radiation Belt Storm Probe Ion Composition Experiment (RBSPICE) instrument aboard the Van Allan Probes spacecraft show considerable variability during quiet solar wind and geomagnetic time periods. Such variability is apparent from orbit to orbit (˜9 h) of the spacecraft and is observed to be ˜50-100% of the nominal flux. Using data from the Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) instrument, also aboard the Van Allen Probes spacecraft, we identify that a dominant source of this variability is from ULF waveforms with periods of tens of seconds. These periods correspond to the bounce resonant timescales of the ring current He ions being measured by RBSPICE. A statistical survey using the particle and field data for one full spacecraft precession period (approximately 2 years) shows that the wave and He ion flux variations are generally anticorrelated, suggesting the bounce resonant pitch angle scattering process as a major component in the scattering of He ions.

Phase noise analysis of a 10-GHz optical injection-locked vertical-cavity surface-emitting laser-based optoelectronic oscillator

NASA Astrophysics Data System (ADS)

Coronel, Juan; Varón, Margarita; Rissons, Angélique

2016-09-01

The optical injection locking (OIL) technique is proposed to reduce the phase noise of a carrier generated for a vertical-cavity surface-emitting laser (VCSEL)-based optoelectronic oscillator. The OIL technique permits the enhancement of the VCSEL direct modulation bandwidth as well as the stabilization of the optical noise of the laser. A 2-km delay line, 10-GHz optical injection-locked VCSEL-based optoelectronic oscillator (OILVBO) was implemented. The internal noise sources of the optoelectronic oscillator components were characterized and analyzed to understand the noise conversion of the system into phase noise in the oscillator carrier. The implemented OILVBO phase noise was -105.7 dBc/Hz at 10 kHz from the carrier; this value agrees well with the performed simulated analysis. From the computed and measured phase noise curves, it is possible to infer the noise processes that take place inside the OILVBO. As a second measurement of the oscillation quality, a time-domain analysis was done through the Allan's standard deviation measurement, reported for first time for an optoelectronic oscillator using the OIL technique.

Editorial: Focus on Extra Space Dimensions

NASA Astrophysics Data System (ADS)

Agashe, Kaustubh; Pomarol, Alex

2010-07-01

Experiments at the Large Hadron Collider (LHC) have just started. In addition to verifying the Standard Model (SM) of particle physics, these experiments will probe a new energy frontier and test extensions of the SM. The existence of extra dimensions is one of the most attractive possibilities for physics beyond the SM. This focus issue contains a collection of articles addressing both theoretical and phenomenological aspects of extra-dimensional models. Focus on Extra Space Dimensions Contents Minimal universal extra dimensions in CalcHEP/CompHEP AseshKrishna Datta, Kyoungchul Kong and Konstantin T Matchev Disordered extra dimensions Karim Benakli Codimension-2 brane-bulk matching: examples from six and ten dimensions Allan Bayntun, C P Burgess and Leo van Nierop Gauge threshold corrections in warped geometry Kiwoon Choi, Ian-Woo Kim and Chang Sub Shin Holographic methods and gauge-Higgs unification in flat extra dimensions Marco Serone Soft-wall stabilization Joan A Cabrer, Gero von Gersdorff and Mariano Quirós Warped five-dimensional models: phenomenological status and experimental prospects Hooman Davoudiasl, Shrihari Gopalakrishna, Eduardo Pontón and José Santiago

Noise modeling and analysis of an IMU-based attitude sensor: improvement of performance by filtering and sensor fusion

NASA Astrophysics Data System (ADS)

K., Nirmal; A. G., Sreejith; Mathew, Joice; Sarpotdar, Mayuresh; Suresh, Ambily; Prakash, Ajin; Safonova, Margarita; Murthy, Jayant

2016-07-01

We describe the characterization and removal of noises present in the Inertial Measurement Unit (IMU) MPU- 6050, which was initially used in an attitude sensor, and later used in the development of a pointing system for small balloon-borne astronomical payloads. We found that the performance of the IMU degraded with time because of the accumulation of different errors. Using Allan variance analysis method, we identified the different components of noise present in the IMU, and verified the results by the power spectral density analysis (PSD). We tried to remove the high-frequency noise using smooth filters such as moving average filter and then Savitzky Golay (SG) filter. Even though we managed to filter some high-frequency noise, these filters performance wasn't satisfactory for our application. We found the distribution of the random noise present in IMU using probability density analysis and identified that the noise in our IMU was white Gaussian in nature. Hence, we used a Kalman filter to remove the noise and which gave us good performance real time.

Coordinated In Situ Nanosims Analyses of H-C-O Isotopes in ALH 84001 Carbonates

NASA Technical Reports Server (NTRS)

Usui, T.; Alexander, C. M. O'D.; Wang, J.; Simon, J. I.; Jones, J. H.

2016-01-01

The surface geology and geomorphology of Mars indicate that it was once warm enough to maintain a large body of liquid water on its surface, though such a warm environment might have been transient. This study reports the hydrogen, carbon, and oxygen isotope compositions of the ancient atmosphere/hydrosphere of Mars based on in situ ion microprobe analyses of approximately 4 Ga-old carbonates in Allan Hills (ALH) 84001. The ALH 84001 carbonates are the most promising targets because they are thought to have formed from fluid that was closely associated with the Noachian atmosphere. While there are a number of carbon and oxygen isotope studies of the ALH 84001 carbonates, in situ hydrogen isotope analyses of these carbonates are limited and were reported more than a decade ago. Well-documented coordinated in situ analyses of carbon, oxygen and hydrogen isotopes provide an internally consistent dataset that can be used to constrain the nature of the Noachian atmosphere/hydrosphere and may eventually shed light on the hypothesis of ancient watery Mars.

Advances in positron and electron scattering*

NASA Astrophysics Data System (ADS)

Limão-Vieira, Paulo; García, Gustavo; Krishnakumar, E.; Petrović, Zoran; Sullivan, James; Tanuma, Hajime

2016-10-01

The topical issue on Advances in Positron and Electron Scattering" combines contributions from POSMOL 2015 together with others devoted to celebrate the unprecedented scientific careers of our loyal colleagues and trusted friends Steve Buckman (Australian National University, Australia) and Michael Allan (University of Fribourg, Switzerland) on the occasion of their retirements. POSMOL 2015, the XVIII International Workshop on Low-Energy Positron and Positronium Physics and the XIX International Symposium on Electron-Molecule Collisions and Swarms, was held at Universidade NOVA de Lisboa, Lisboa, Portugal, from 17-20 July 2015. The international workshop and symposium allowed to achieve a very privileged forum of sharing and developing our scientific expertise on current aspects of positron, positronium and antiproton interactions with electrons, atoms, molecules and solid surfaces, and related topics, as well as electron interactions with molecules in both gaseous and condensed phases. Particular topics include studies of electron interactions with biomolecules, electron induced surface chemistry and the study of plasma processes. Recent developments in the study of swarms are also fully addressed.

Extraterrestrial Amino Acids in Ureilites Including Almahata Sitta

NASA Technical Reports Server (NTRS)

Burton, A. S.; Glavin, D. P.; Callahan, M. P.; Dworkin, J. P.

2011-01-01

Ureilites are a class of meteorites that lack chondrules (achondrites) but have relatively high carbon abundances, averaging approx.3 wt %. Using highly sensitive liquid chromatography coupled with UV fluorescence and time-of-flight mass spectrometry (LC-FD/ToF-MS), it was recently determined that there are amino acids in. fragment 94 of the Almahata Sitta ureilite[l]. Based on the presence of amino acids that are rare in the Earth's biosphere, as well as the near-racemic enantiomeric ratios of marry of the more common amino acids, it was concluded that most of the detected amino acids were indigenous to the meteorite. Although the composition of the Almahata Sitta ureilite appears to be unlike other recovered ureilites, the discovery of amino acids in this meteorite raises the question of whether other ureilites rnav also contain amino acids. Herein we present the results of LC-FDlTo.F-MS analyses of: a sand sample from the Almahata Sitta strewn held, Almahata Sitta fragments 425 (an ordinary H5 chondrite) and 427 (ureilite), as well as an Antarctic ureilite (Allan lulls, ALHA 77257).

Fiber-Amplifier-Enhanced QEPAS Sensor for Simultaneous Trace Gas Detection of NH3 and H2S

PubMed Central

Wu, Hongpeng; Dong, Lei; Liu, Xiaoli; Zheng, Huadan; Yin, Xukun; Ma, Weiguang; Zhang, Lei; Yin, Wangbao; Jia, Suotang

2015-01-01

A selective and sensitive quartz enhanced photoacoustic spectroscopy (QEPAS) sensor, employing an erbium-doped fiber amplifier (EDFA), and a distributed feedback (DFB) laser operating at 1582 nm was demonstrated for simultaneous detection of ammonia (NH3) and hydrogen sulfide (H2S). Two interference-free absorption lines located at 6322.45 cm−1 and 6328.88 cm−1 for NH3 and H2S detection, respectively, were identified. The sensor was optimized in terms of current modulation depth for both of the two target gases. An electrical modulation cancellation unit was equipped to suppress the background noise caused by the stray light. An Allan-Werle variance analysis was performed to investigate the long-term performance of the fiber-amplifier-enhanced QEPAS sensor. Benefitting from the high power boosted by the EDFA, a detection sensitivity (1σ) of 52 parts per billion by volume (ppbv) and 17 ppbv for NH3 and H2S, respectively, were achieved with a 132 s data acquisition time at atmospheric pressure and room temperature. PMID:26506351

Atomic-scale Visualization of Electronic Nematicity and Cooper Pairing in Iron-based Superconductors

NASA Astrophysics Data System (ADS)

Allan, Milan P.

2013-03-01

The mechanism of high-temperature superconductivity in the relatively novel iron-based high-Tc superconductors is unresolved, both in terms of how the phases evolve with doping, and in terms of the actual Cooper pairing process. To explore these issues, we used spectroscopic-imaging scanning tunneling microscopy to study the electronic structure of CaFe2As2 in the antiferromagnetic-orthorhombic `parent' state from which the superconductivity emerges. We discovered and visualized the now widely studied electronic `nematicity' of this phase, whose suppression is associated with the emergence of superconductivity (Science 327, 181, 2010). As subsequent transport experiments discovered a related anisotropic conductance which increases with dopant concentration, the interplay between the electronic structure surrounding each dopant atom, quasiparticle scattering therefrom, and the transport nematicity has become a pivotal focus of research. We find that substituting Co for Fe atoms in underdoped Ca(Fe1-xCox)2As2 generates a dense population of identical and strongly anisotropic impurity states that are distributed randomly but aligned with the antiferromagnetic a-axis. We also demonstrate, by imaging their surrounding interference patterns, that these impurity states scatter quasiparticles and thus influence transport in a highly anisotropic manner (M.P. Allan et al., 2013). Next, we studied the momentum dependence of the energy gaps of iron-based superconductivity, now focusing on LiFeAs. If strong electron-electron interactions mediate the Cooper pairing, then momentum-space anisotropic superconducting energy gaps Δi (k) were predicted by multiple techniques to appear on the different electronic bands i. We introduced intraband Bogoliubov quasiparticle scattering interference (QPI) techniques for the determination of anisotropic energy gaps to test these hypotheses and discovered the anisotropy, magnitude, and relative orientations of the energy gaps on multiple

Designing and Assessing Restored Meandering River Planform Using RVR Meander

NASA Astrophysics Data System (ADS)

Langendoen, E. J.; Abad, J. D.; Motta, D.; Frias, C. E.; Wong, M.; Barnes, B. J.; Anderson, C. D.; Garcia, M. H.; MacDonald, T. E.

2013-12-01

The ongoing modification and resulting reduction in water quality of U.S. rivers have led to a significant increase in river restoration projects over the last two decades. The increased interest in restoring degraded streams, however, has not necessarily led to improved stream function. Palmer and Allan (2005) found that many restoration projects fail to achieve their objectives due to the lack of policies to support restoration standards, to promote proven methods and to provide basic data needed for planning and implementation. Proven models of in-stream and riparian processes could be used not only to guide the design of restoration projects but also to assess both pre- and post-project indicators of ecological integrity. One of the most difficult types of river restoration projects concern reconstructing a new channel, often with an alignment and channel form different from those of the degraded pre-project channel. Recreating a meandering planform to provide longitudinal and lateral variability of flow and bed morphology to improve in-stream aquatic habitat is often desired. Channel meander planform is controlled by a multitude of variables, for example channel width to depth ratio, radius of curvature to channel width ratio, bankfull discharge, roughness, bed-material physical characteristics, bed material transport, resistance to erosion of the floodplain soils, riparian vegetation, etc. Therefore, current practices that use simple, empirically based relationships or reference reaches have led to failure in several instances, for example a washing out of meander bends or a highly unstable planform, because they fail to address the site-specific conditions. Recently, progress has been made to enhance a physically- and process-based model, RVR Meander, for rapid analysis of meandering river morphodynamics with reduced empiricism. For example, lateral migration is based on measurable physical properties of the floodplain soils and riparian vegetation versus

Surface Brightness Test and Plasma Redshift

NASA Astrophysics Data System (ADS)

Brynjolfsson, Ari

2006-03-01

The plasma redshift of photons in a hot sparse plasma follows from basic axioms of physics. It has no adjustable parameters (arXiv:astro-ph/0406437). Both the distance-redshift relation and the magnitude-redshift relation for supernovae and galaxies are well-defined functions of the average electron densities in intergalactic space. We have previously shown that the predictions of the magnitude-redshift relation in plasma- redshift cosmology match well the observed relations for the type Ia supernovae (SNe). No adjustable parameters such as the time variable ``dark energy'' and ``dark matter'' are needed. We have also shown that plasma redshift cosmology predicts well the intensity and black body spectrum of the cosmic microwave background (CMB). Plasma redshift explains also the spectrum below and above the 2.73 K black body CMB, and the X-ray background. In the following, we will show that the good observations and analyses of the relation between surface brightness and redshift for galaxies, as determined by Allan Sandage and Lori M. Lubin in 2001, are well predicted by the plasma redshift. All these relations are inconsistent with cosmic time dilation and the contemporary big-bang cosmology.

Piezoresistive silicon nanowire resonators as embedded building blocks in thick SOI

NASA Astrophysics Data System (ADS)

Nasr Esfahani, Mohammad; Kilinc, Yasin; Çagatay Karakan, M.; Orhan, Ezgi; Hanay, M. Selim; Leblebici, Yusuf; Erdem Alaca, B.

2018-04-01

The use of silicon nanowire resonators in nanoelectromechanical systems for new-generation sensing and communication devices faces integration challenges with higher-order structures. Monolithic and deterministic integration of such nanowires with the surrounding microscale architecture within the same thick crystal is a critical aspect for the improvement of throughput, reliability and device functionality. A monolithic and IC-compatible technology based on a tuned combination of etching and protection processes was recently introduced yielding silicon nanowires within a 10 μ m-thick device layer. Motivated by its success, the implications of the technology regarding the electromechanical resonance are studied within a particular setting, where the resonator is co-fabricated with all terminals and tuning electrodes. Frequency response is measured via piezoresistive readout with frequency down-mixing. Measurements indicate mechanical resonance with frequencies as high as 100 MHz exhibiting a Lorentzian behavior with proper transition to nonlinearity, while Allan deviation on the order of 3-8 ppm is achieved. Enabling the fabrication of silicon nanowires in thick silicon crystals using conventional semiconductor manufacturing, the present study thus demonstrates an alternative pathway to bottom-up and thin silicon-on-insulator approaches for silicon nanowire resonators.

Utilization of the Deep Space Atomic Clock for Europa Gravitational Tide Recovery

NASA Technical Reports Server (NTRS)

Seubert, Jill; Ely, Todd

2015-01-01

Estimation of Europa's gravitational tide can provide strong evidence of the existence of a subsurface liquid ocean. Due to limited close approach tracking data, a Europa flyby mission suffers strong coupling between the gravity solution quality and tracking data quantity and quality. This work explores utilizing Low Gain Antennas with the Deep Space Atomic Clock (DSAC) to provide abundant high accuracy uplink-only radiometric tracking data. DSAC's performance, expected to exhibit an Allan Deviation of less than 3e-15 at one day, provides long-term stability and accuracy on par with the Deep Space Network ground clocks, enabling one-way radiometric tracking data with accuracy equivalent to that of its two-way counterpart. The feasibility of uplink-only Doppler tracking via the coupling of LGAs and DSAC and the expected Doppler data quality are presented. Violations of the Kalman filter's linearization assumptions when state perturbations are included in the flyby analysis results in poor determination of the Europa gravitational tide parameters. B-plane targeting constraints are statistically determined, and a solution to the linearization issues via pre-flyby approach orbit determination is proposed and demonstrated.

KSC-2012-2582

NASA Image and Video Library

2012-04-09

CAPE CANAVERAL, Fla. – Aboard NASA’s Freedom Star boat, from left, Boatswain Allan Gravina at the wheel, Captain Mike Nicholas hidden, Aerospace Technician Darin Schuster and Marine Operations Manager Joe Chaput, all with United Space Alliance, monitor the progress as NASA’s Mobile Aerospace Reconnaissance System, or MARS, secured on the boat, is being prepared for a day of testing in the Atlantic Ocean off the coast of Port Canaveral in Florida. MARS, run by NASA’s Langley Research Center in Hampton, Va., with its spatial, hyperspectral, thermal, and directed energy capabilities will be used for thermal imaging testing for the upcoming SpaceX Falcon 9 and Dragon capsule test flight to the International Space Station. During today’s test, the MARS X-band radar and kineto tracking mount KTM were tested to ensure that they were synchronized to receive a rocket launch feed. The radar was used to identify an object to see if the KTM could lock on to and track it. The MARS team performed maintenance on the system, confirmed communications links, and tested the design of the mounting system and environmental enclosure. Photo credit: NASA/Cory Huston

KSC-2012-2583

NASA Image and Video Library

2012-04-09

CAPE CANAVERAL, Fla. – Aboard NASA’s Freedom Star boat, Captain Mike Nicholas in foreground, Boatswain Allan Gravina at the wheel, and Marine Operations Manager Joe Chaput, all with United Space Alliance, monitor the progress as NASA’s Mobile Aerospace Reconnaissance System, or MARS, secured on the boat, is being prepared for a day of testing in the Atlantic Ocean off the coast of Port Canaveral in Florida. MARS, run by NASA’s Langley Research Center in Hampton, Va., with its spatial, hyperspectral, thermal, and directed energy capabilities will be used for thermal imaging testing for the upcoming SpaceX Falcon 9 and Dragon capsule test flight to the International Space Station. During today’s test, the MARS X-band radar and kineto tracking mount KTM were tested to ensure that they were synchronized to receive a rocket launch feed. The radar was used to identify an object to see if the KTM could lock on to and track it. The MARS team performed maintenance on the system, confirmed communications links, and tested the design of the mounting system and environmental enclosure. Photo credit: NASA/Cory Huston

Atomic fountain clock with very high frequency stability employing a pulse-tube-cryocooled sapphire oscillator.

PubMed

Takamizawa, Akifumi; Yanagimachi, Shinya; Tanabe, Takehiko; Hagimoto, Ken; Hirano, Iku; Watabe, Ken-ichi; Ikegami, Takeshi; Hartnett, John G

2014-09-01

The frequency stability of an atomic fountain clock was significantly improved by employing an ultra-stable local oscillator and increasing the number of atoms detected after the Ramsey interrogation, resulting in a measured Allan deviation of 8.3 × 10(-14)τ(-1/2)). A cryogenic sapphire oscillator using an ultra-low-vibration pulse-tube cryocooler and cryostat, without the need for refilling with liquid helium, was applied as a local oscillator and a frequency reference. High atom number was achieved by the high power of the cooling laser beams and optical pumping to the Zeeman sublevel m(F) = 0 employed for a frequency measurement, although vapor-loaded optical molasses with the simple (001) configuration was used for the atomic fountain clock. The resulting stability is not limited by the Dick effect as it is when a BVA quartz oscillator is used as the local oscillator. The stability reached the quantum projection noise limit to within 11%. Using a combination of a cryocooled sapphire oscillator and techniques to enhance the atom number, the frequency stability of any atomic fountain clock, already established as primary frequency standard, may be improved without opening its vacuum chamber.

A New Continuous Rotation IMU Alignment Algorithm Based on Stochastic Modeling for Cost Effective North-Finding Applications

PubMed Central

Li, Yun; Wu, Wenqi; Jiang, Qingan; Wang, Jinling

2016-01-01

Based on stochastic modeling of Coriolis vibration gyros by the Allan variance technique, this paper discusses Angle Random Walk (ARW), Rate Random Walk (RRW) and Markov process gyroscope noises which have significant impacts on the North-finding accuracy. A new continuous rotation alignment algorithm for a Coriolis vibration gyroscope Inertial Measurement Unit (IMU) is proposed in this paper, in which the extended observation equations are used for the Kalman filter to enhance the estimation of gyro drift errors, thus improving the north-finding accuracy. Theoretical and numerical comparisons between the proposed algorithm and the traditional ones are presented. The experimental results show that the new continuous rotation alignment algorithm using the extended observation equations in the Kalman filter is more efficient than the traditional two-position alignment method. Using Coriolis vibration gyros with bias instability of 0.1°/h, a north-finding accuracy of 0.1° (1σ) is achieved by the new continuous rotation alignment algorithm, compared with 0.6° (1σ) north-finding accuracy for the two-position alignment and 1° (1σ) for the fixed-position alignment. PMID:27983585

Sociocultural influences on science and on science identities

NASA Astrophysics Data System (ADS)

Guerra, Andreia; Rezende, Flavia

2017-06-01

Angela Chapman and Allan Feldman (2016) conducted a study that aimed to exam how a group of diverse urban high school students were affected by the participation in a contextually based authentic science experience. The analysis of all data led the authors to conclude that the experience of authentic science positively influenced the science identity of students and promoted a shift in perceptions from stereotypical to more diverse views of scientists. For the purpose of this forum paper, we concentrated on the unexpected results of Hispanic students in the IAS instrument. In the authors' interpretation, Hispanic students were classified as non science identities because they do not feel recognized as a particular kind of student in that school, being possibly more marginalized than other students. We tried to expand the discussion bringing the contribution of a sociocultural approach of science construction and of science identity to enrich some of the issues involved. Our concise analysis does not allow conclusions about the Hispanic students' results, but we believe it helped to understand sociocultural problems involved in their science identity and to reveal the inequality in science production as one of these problems.

6DOF Testing of the SLS Inertial Navigation Unit

NASA Technical Reports Server (NTRS)

Geohagan, Kevin W.; Bernard, William P.; Oliver, T. Emerson; Strickland, Dennis J.; Leggett, Jared O.

2018-01-01

The Navigation System on the NASA Space Launch System (SLS) Block 1 vehicle performs initial alignment of the Inertial Navigation System (INS) navigation frame through gyrocompass alignment (GCA). In lieu of direct testing of GCA accuracy in support of requirement verification, the SLS Navigation Team proposed and conducted an engineering test to, among other things, validate the GCA performance and overall behavior of the SLS INS model through comparison with test data. This paper will detail dynamic hardware testing of the SLS INS, conducted by the SLS Navigation Team at Marshall Space Flight Center's 6DOF Table Facility, in support of GCA performance characterization and INS model validation. A 6-DOF motion platform was used to produce 6DOF pad twist and sway dynamics while a simulated SLS flight computer communicated with the INS. Tests conducted include an evaluation of GCA algorithm robustness to increasingly dynamic pad environments, an examination of GCA algorithm stability and accuracy over long durations, and a long-duration static test to gather enough data for Allan Variance analysis. Test setup, execution, and data analysis will be discussed, including analysis performed in support of SLS INS model validation.

Measuring atmospheric visibility cavity attenuated phase shift spectroscopy

NASA Astrophysics Data System (ADS)

Jie, Guo; Ye, Shan-Shan; Yang, Xiao; Han, Ye-Xing; Tang, Huai-Wu; Yu, Zhi-Wei

2016-10-01

In the paper, an accurate and sensitive cavity attenuated phase shift spectroscopy (CAPS) system was used to monitor the atmospheric visibility coefficient in urban areas. The CAPS system, which detects the atmospheric visibility within a 10 nm bandpass centered at 532 nm, comprises a green LED with center wavelength in 532nm, a resonant optical cavity (36 cm length), a Photo Multiplier Tube detector and a lock in amplifier. The performance of the CAPS system was evaluated by measuring of the stability and response of the system. The minima ( 0.06 Mm-1) in the Allan plots show the optimum average time( 80s) for optimum detection performance of the CAPS system. The 2L/min flow rate, the CAPS system rise and fall response time is about 15 s, so as to realize the fast measurement of visibility. By comparing the forward scatter visibility meter measurement results, the CAPS system measurement results are verified reliably, and have high precision measurement. These figures indicate that this method has the potential to become one of the most sensitive on-line analytical techniques for atmospheric visibility detection.

Standard deviation of the mean and other time series properties of voltages measured with a digital lock-in amplifier

NASA Astrophysics Data System (ADS)

Witt, Thomas J.; Fletcher, N. E.

2010-10-01

We investigate some statistical properties of ac voltages from a white noise source measured with a digital lock-in amplifier equipped with finite impulse response output filters which introduce correlations between successive voltage values. The main goal of this work is to propose simple solutions to account for correlations when calculating the standard deviation of the mean (SDM) for a sequence of measurement data acquired using such an instrument. The problem is treated by time series analysis based on a moving average model of the filtering process. Theoretical expressions are derived for the power spectral density (PSD), the autocorrelation function, the equivalent noise bandwidth and the Allan variance; all are related to the SDM. At most three parameters suffice to specify any of the above quantities: the filter time constant, the time between successive measurements (both set by the lock-in operator) and the PSD of the white noise input, h0. Our white noise source is a resistor so that the PSD is easily calculated; there are no free parameters. Theoretical expressions are checked against their respective sample estimates and, with the exception of two of the bandwidth estimates, agreement to within 11% or better is found.

Sensitive detection of formaldehyde using an interband cascade laser near 3.6 μm

DOE PAGES

Ren, Wei; Luo, Longqiang; Tittel, Frank K.

2015-12-31

Here, we report the development of a formaldehyde (H 2CO) trace gas sensor using a continuous wave (CW), thermoelectrically-cooled (TEC), distributed-feedback interband cascade laser (DFB-ICL) at 3.6 μm. Wavelength modulation spectroscopy was used to detect the second harmonic spectra of a strong H 2CO absorption feature centered at 2778.5 cm -1 (3599 nm) in its ν 1 fundamental vibrational band. A compact and novel multipass cell (7.6-cm physical length and 32-ml sampling volume) was implemented to achieve an effective optical path length of 3.75 m. A minimum detection limit of 6 parts per billion (ppb) at an optimum gas pressuremore » of 200 Torr was achieved with a 1-s data acquisition time. An Allan-Werle deviation analysis was performed to investigate the long-term stability of the sensor system and a 1.5 ppb minimum detectable concentration could be achieved by averaging up to 140 s. Absorption interference eeffects from atmospheric H 2O (2%) and CH 4(5 ppm) were also analyzed in this work and proved to be insignificant for the current sensor configuration.« less

Meteorite Infall and Transport in Antarctica: An Analysis of Icefields as Accumulation Surfaces

NASA Technical Reports Server (NTRS)

Benoit, P. H.; Sears, D. W. G.

1997-01-01

Over 10,000 meteorite fragments have been collected on only a dozen or so small icefields in Antarctica. The terrestrial history of these meteorites is important, both from the perspective of the effects of their ambient environment on the meteorites themselves, and on the information that can be derived in relation to ice flow and ice stability over periods of time up to 1 million years. We discuss the relative importance of meteorite infall, and ice and aeolian transport in creating meteorite accumulations and the importance of ice and aeolian transport and weathering in removing meteorites at various icefields in Antarctica. The present analysis is confined to equibrated ordinary chondrites. We use the natural thermoluminescence (TL) to to examine the effects of weathering. Natural TL is used in combination with size analysis to gauge the effects of aeolian transport. Some icefields, especially the Lewis Cliff Ice Tongue, are dominated by wind-transported fragments, while others, including the Far Western field at Allan Hills, have lost fragments. It appears that most Antarctic icefields preserve meteorite collections on time scales of a few tens of thousands of years.

SESAME, A 3rd Generation Synchrotron Light Source for the Middle East

DOE Office of Scientific and Technical Information (OSTI.GOV)

Einfeld, D.; Hasnain, S.S.; Sayers, Z.

2004-05-12

Developed under the auspices of UNESCO, SESAME (Synchrotron-light for Experimental Science and Applications in the Middle East) will be a major international research centre in the Middle East and Mediterranean region. On 6th of January 2003, the official foundation of SESAME took place. The facility is located in Allan, Jordan, 30 km North-West of Amman. As of August 2003 the Founding Members are Bahrain, Egypt, Iran, Israel, Jordan, Pakistan, Palestine, Turkey and United Arabic Emirates, representing a population of over 300 million. SESAME will be a 2.5 GeV 3rd Generation light source (emittance 24.6 nm.rad, circumference {approx}125m). About 40% ofmore » the circumference is available for insertion devices (average length 2.75m) in 13 straight sections. Beam lines are up to 36m. The site and a building are provided by Jordan. Construction started in August 2003. The scientific program will start with up to 6 beam lines: MAD Protein Crystallography, SAXS and WAXS for polymers and proteins, Powder Diffraction for material science, UV/VUV/SXR Photoelectron Spectroscopy and Photoabsorption Spectroscopy, IR Spectroscopy, and EXAFS.« less

High T3, Low T4 Serum Levels in Mct8 Deficiency Are Not Caused by Increased Hepatic Conversion through Type I Deiodinase

PubMed Central

Wirth, Eva K.; Rijntjes, Eddy; Meyer, Franziska; Köhrle, Josef; Schweizer, Ulrich

2015-01-01

Background The Allan-Herndon-Dudley syndrome is a severe psychomotor retardation accompanied by specific changes in circulating thyroid hormone levels (high T3, low T4). These are caused by mutations in the thyroid hormone transmembrane transport protein monocarboxylate transporter 8 (MCT8). Objective: To test the hypothesis that circulating low T4 and high T3 levels are caused by enhanced conversion of T4 via increased activity of hepatic type I deiodinase (Dio1). Methods We crossed mice deficient in Mct8 with mice lacking Dio1 activity in hepatocytes. Translation of the selenoenzyme Dio1 was abrogated by hepatocyte-specific inactivation of selenoprotein biosynthesis. Results Inactivation of Dio1 activity in the livers of global Mct8-deficient mice does not restore normal circulating thyroid hormone levels. Conclusions Our data suggest that although hepatic Dio1 activity is increased in Mct8-deficient mice, it does not cause the observed abnormal circulating thyroid hormone levels. Since global inactivation of Dio1 in Mct8-deficient mice does normalize circulating thyroid hormone levels, the underlying mechanism and relevant tissues involved remain to be elucidated. PMID:26601078

New kind of injection-locked oscillator and its corresponding long-term stability control.

PubMed

Hong, Jun; Liu, An; Wang, Xiao-hu; Yao, Sheng-xing; Li, Zu-ling

2015-09-20

A new type of opto-electronic hybrid oscillator is proposed for the first time, to the best of our knowledge, and verified by experiments in this paper. Typical electronic oscillator-dielectric resonator oscillator as the first injection source is used to injection lock the first long-fiber loop-based opto-electronic oscillator (OEO); then its output is used to injection lock the second long-fiber opto-electronic oscillator. Using this method, low-phase noise output signal can be obtained. Experiments show that single side-band (SSB) phase noise of a 9.5 GHz oscillation signal at 10 kHz offset frequency decreases from -123 to -135  dBc/Hz after the first injection, then, through the second injection, the SSB phase noise drops down to -146  dBc/Hz. In order to solve the long-term stability problem of the above oscillator, a new stability-control circuit also is designed and verified by experiments. Experiments show that the Allan deviation decreases from 9.0×10(-11) to 2.2×10(-12) during 1 s after the long-term stability-control circuit being used.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Argence, B.; Halloin, H.; Jeannin, O.

We have developed a 532 nm iodine stabilized laser system that may be suitable for the LISA mission (Laser Interferometer Space Antenna) or other future spaceborne missions. This system is based on an externally frequency-doubled Nd:YAG laser source and uses the molecular transfer spectroscopy technique for the frequency stabilization. This technique has been optimized for LISA: compactness (less than 1.1x1.1 m{sup 2}), vacuum compatibility, ease of use and initialization, minimization of the number of active components (acousto-optic modulators are both used for frequency shifting and phase modulating the pump beam). By locking on the a{sub 10} hyperfine component of themore » R(56)32-0 transition, we find an Allan standard deviation ({sigma}) of 3x10{sup -14} at 1 s and {sigma}<2x10{sup -14} for 20 s{<=}{tau}{<=}10{sup 3} s. In terms of linear spectral density, this roughly corresponds to a stability better than 30 Hz/{radical}(Hz) between 10{sup -2} and 1 Hz with a stability decrease close to 1/f below 10 mHz.« less

Maintenance of Time and Frequency in the DSN Using the Global Positioning System

NASA Technical Reports Server (NTRS)

Clements, P. A.; Kirk, A.; Borutzki, S. E.

1985-01-01

The Deep Space Network must maintain time and frequency within specified limits in order to accurately track the spacecraft engaged in deep space exploration. The DSN has three tracking complexes, located approximately equidistantly around the Earth. Various methods are used to coordinate the clocks among the three complexes. These methods include Loran-C, TV Line 10, very long baseline interferometry (VLBI), and the Global Positioning System (GPS). The GPS is becoming increasingly important because of the accuracy, precision, and rapid availability of the data; GPS receivers have been installed at each of the DSN complexes and are used to obtain daily time offsets between the master clock at each site and UTC(USNO/NBS). Calculations are made to obtain frequency offsets and Allan variances. These data are analyzed and used to monitor the performance of the hydrogen masers that provide the reference frequencies for the DSN frequency and timing system (DFT). A brief history of the GPS timing receivers in the DSN, a description of the data and information flow, data on the performance of the DSN master clocks and GPS measurement system, and a description of hydrogen maser frequency steering using these data are presented.

Sensitive detection of formaldehyde using an interband cascade laser near 3.6 μm

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ren, Wei; Luo, Longqiang; Tittel, Frank K.

Here, we report the development of a formaldehyde (H 2CO) trace gas sensor using a continuous wave (CW), thermoelectrically-cooled (TEC), distributed-feedback interband cascade laser (DFB-ICL) at 3.6 μm. Wavelength modulation spectroscopy was used to detect the second harmonic spectra of a strong H 2CO absorption feature centered at 2778.5 cm -1 (3599 nm) in its ν 1 fundamental vibrational band. A compact and novel multipass cell (7.6-cm physical length and 32-ml sampling volume) was implemented to achieve an effective optical path length of 3.75 m. A minimum detection limit of 6 parts per billion (ppb) at an optimum gas pressuremore » of 200 Torr was achieved with a 1-s data acquisition time. An Allan-Werle deviation analysis was performed to investigate the long-term stability of the sensor system and a 1.5 ppb minimum detectable concentration could be achieved by averaging up to 140 s. Absorption interference eeffects from atmospheric H 2O (2%) and CH 4(5 ppm) were also analyzed in this work and proved to be insignificant for the current sensor configuration.« less

Pressure-Dependent Detection of Carbon Monoxide Employing Wavelength Modulation Spectroscopy Using a Herriott-Type Cell.

PubMed

Li, Chuanliang; Wu, Yingfa; Qiu, Xuanbing; Wei, Jilin; Deng, Lunhua

2017-05-01

Wavelength modulation spectroscopy (WMS) combined with a multipass absorption cell has been used to measure a weak absorption line of carbon monoxide (CO) at 1.578 µm. A 0.95m Herriott-type cell provides an effective absorption path length of 55.1 m. The WMS signals from the first and second harmonic output of a lock-in amplifier (WMS-1 f and 2 f, respectively) agree with the Beer-Lambert law, especially at low concentrations. After boxcar averaging, the minimum detection limit achieved is 4.3 ppm for a measurement time of 0.125 s. The corresponding normalized detection limit is 84 ppm m Hz -1/2 . If the integrated time is increased to 88 s, the minimum detectable limit of CO can reach to 0.29 ppm based on an Allan variation analysis. The pressure-dependent relationship is validated after accounting for the pressure factor in data processing. Finally, a linear correlation between the WMS-2 f amplitudes and gas concentrations is obtained at concentration ratios less than 15.5%, and the accuracy is better than 92% at total pressure less than 62.7 Torr.

Performance of a Ka-band transponder breadboard for deep-space applications

NASA Technical Reports Server (NTRS)

Mysoor, N. R.; Lane, J. P.; Kayalar, S.; Kermode, A. W.

1995-01-01

This article summarizes the design concepts applied in the development of and advanced Ka-band (34.4 GHz/32 GHz) transponder breadboard for the next generation of space communications systems applications. The selected architecture upgrades the X-band (7.2 GHz/8.4 GHz) deep-space transponder (DST) to provide Da-band up/Ka- and X-band down capability. The Ka-band transponder breadboard incorporates several state-of-the-art components, including sampling mixers, a Ka-band dielectric resonator oscillator, and microwave monolithic integrated circuits (MMICs). The MMICs that were tested in the breadboard include upconverters, downconverters, automatic gain control circuits, mixers, phase modulators, and amplifiers. The measured receiver dynamic range, tracking range, acquisition rate, static phase error, and phase jitter characteristics of the Ka-band breadboard interfaced to the advanced engineering model X-band DST are in good agreement with the expected performance. The results show a receiver tracking threshold of -149 dBm with a dynamic range of 80 dB and a downlink phase jitter of 7 deg rms. The analytical results of phase noise and Allan standard deviation are in good agreement with the experimental results.

The JPL trapped mercury ion frequency standard

NASA Technical Reports Server (NTRS)

Prestage, J. D.; Dick, G. J.; Maleki, L.

1988-01-01

In order to provide frequency standards for the Deep Space Network (DSN) which are more stable than present-day hydrogen masers, a research task was established under the Advanced Systems Program of the TDA to develop a Hg-199(+) trapped ion frequency standard. The first closed-loop operation of this kind is described. Mercury-199 ions are confined in an RF trap and are state-selected through the use of optical pumping with 194 nm UV light from a Hg-202 discharge lamp. Absorption of microwave radiation at the hyperfine frequency (40.5 GHz) is signaled by atomic fluorescence of the UV light. The frequency of a 40.5 GHz oscillator is locked to a 1.6 Hz wide atomic absorption line of the trapped ions. The measured Allan variance of this locked oscillator is currently gamma sub y (pi) = 4.4 x 10 to the minus 12th/square root of pi for 20 is less than pi is less than 320 seconds, which is better stability than the best commercial cesium standards by almost a factor of 2. This initial result was achieved without magnetic shielding and without regulation of ion number.

Asymmetric resonance frequency analysis of in-plane electrothermal silicon cantilevers for nanoparticle sensors

NASA Astrophysics Data System (ADS)

Bertke, Maik; Hamdana, Gerry; Wu, Wenze; Marks, Markus; Suryo Wasisto, Hutomo; Peiner, Erwin

2016-10-01

The asymmetric resonance frequency analysis of silicon cantilevers for a low-cost wearable airborne nanoparticle detector (Cantor) is described in this paper. The cantilevers, which are operated in the fundamental in-plane resonance mode, are used as a mass-sensitive microbalance. They are manufactured out of bulk silicon, containing a full piezoresistive Wheatstone bridge and an integrated thermal heater for reading the measurement output signal and stimulating the in-plane excitation, respectively. To optimize the sensor performance, cantilevers with different cantilever geometries are designed, fabricated and characterized. Besides the resonance frequency, the quality factor (Q) of the resonance curve has a high influence concerning the sensor sensitivity. Because of an asymmetric resonance behaviour, a novel fitting function and method to extract the Q is created, different from that of the simple harmonic oscillator (SHO). For testing the sensor in a long-term frequency analysis, a phase- locked loop (PLL) circuit is employed, yielding a frequency stability of up to 0.753 Hz at an Allan variance of 3.77 × 10-6. This proposed asymmetric resonance frequency analysis method is expected to be further used in the process development of the next-generation Cantor.

Time fluctuation analysis of forest fire sequences

NASA Astrophysics Data System (ADS)

Vega Orozco, Carmen D.; Kanevski, Mikhaïl; Tonini, Marj; Golay, Jean; Pereira, Mário J. G.

2013-04-01

Forest fires are complex events involving both space and time fluctuations. Understanding of their dynamics and pattern distribution is of great importance in order to improve the resource allocation and support fire management actions at local and global levels. This study aims at characterizing the temporal fluctuations of forest fire sequences observed in Portugal, which is the country that holds the largest wildfire land dataset in Europe. This research applies several exploratory data analysis measures to 302,000 forest fires occurred from 1980 to 2007. The applied clustering measures are: Morisita clustering index, fractal and multifractal dimensions (box-counting), Ripley's K-function, Allan Factor, and variography. These algorithms enable a global time structural analysis describing the degree of clustering of a point pattern and defining whether the observed events occur randomly, in clusters or in a regular pattern. The considered methods are of general importance and can be used for other spatio-temporal events (i.e. crime, epidemiology, biodiversity, geomarketing, etc.). An important contribution of this research deals with the analysis and estimation of local measures of clustering that helps understanding their temporal structure. Each measure is described and executed for the raw data (forest fires geo-database) and results are compared to reference patterns generated under the null hypothesis of randomness (Poisson processes) embedded in the same time period of the raw data. This comparison enables estimating the degree of the deviation of the real data from a Poisson process. Generalizations to functional measures of these clustering methods, taking into account the phenomena, were also applied and adapted to detect time dependences in a measured variable (i.e. burned area). The time clustering of the raw data is compared several times with the Poisson processes at different thresholds of the measured function. Then, the clustering measure value

The Frustration of Lady Aberdeen in her Crusade against Tuberculosis in Ireland

PubMed Central

Breathnach, Caoimhghín S; Moynihan, John B

2012-01-01

When in his Annual Report for 1905 the Registrar General for Ireland pointed out to the lately arrived Lord Lieutenant, The Earl of Aberdeen, that annually in every 100 deaths in Ireland 16 were victims of tuberculosis, Lady Aberdeen took notice. In March 1907 she founded the WNHA with the clear duty of taking part in the fight against the appalling ravages of that disease, and organised a Tuberculosis Exhibition the following October. And so began a campaign that led to the building of Peamount Sanatorium in county Dublin, the Allan Ryan Hospital at Ringsend, and the Collier Dispensary in the city centre. However, the Irish parliamentarians at Westminster emasculated the Tuberculosis Prevention (Ireland) Act 1908 by ensuring that notification was not made compulsory. Passage of the National Health Insurance Act (1911) necessitated changes that resulted in the Tuberculosis Prevention (Ireland) Act (1913), but the crucial shortcomings of the earlier Act were not rectified: notification was necessary but still not compulsory. Lady Aberdeen recognised this serious flaw she was powerless to correct, and turned to propaganda, editing Sláinte, a monthly magazine founded in January 1909 by the WNHA, and editing a three-volume account of Ireland’s Crusade Against Tuberculosis (1908-1909). PMID:23536737

Quartz-enhanced photo-acoustic spectroscopy for breath analyses

NASA Astrophysics Data System (ADS)

Petersen, Jan C.; Lamard, Laurent; Feng, Yuyang; Focant, Jeff-F.; Peremans, Andre; Lassen, Mikael

2017-03-01

An innovative and novel quartz-enhanced photoacoustic spectroscopy (QEPAS) sensor for highly sensitive and selective breath gas analysis is introduced. The QEPAS sensor consists of two acoustically coupled micro- resonators (mR) with an off-axis 20 kHz quartz tuning fork (QTF). The complete acoustically coupled mR system is optimized based on finite element simulations and experimentally verified. Due to the very low fabrication costs the QEPAS sensor presents a clear breakthrough in the field of photoacoustic spectroscopy by introducing novel disposable gas chambers in order to avoid cleaning after each test. The QEPAS sensor is pumped resonantly by a nanosecond pulsed single-mode mid-infrared optical parametric oscillator (MIR OPO). Spectroscopic measurements of methane and methanol in the 3.1 μm to 3.7 μm wavelength region is conducted. Demonstrating a resolution bandwidth of 1 cm-1. An Allan deviation analysis shows that the detection limit at optimum integration time for the QEPAS sensor is 32 ppbv@190s for methane and that the background noise is solely due to the thermal noise of the QTF. Spectra of both individual molecules as well as mixtures of molecules were measured and analyzed. The molecules are representative of exhaled breath gasses that are bio-markers for medical diagnostics.

Identification and return of a skull from Tasmania in the Berlin anatomical collection.

PubMed

Winkelmann, Andreas; Teßmann, Barbara

2018-02-01

Following a request by the Australian government, human remains of Australian origin were identified in the anatomical collection of Charité, the medical faculty of Berlin. We initiated an interdisciplinary provenance research on such remains to ensure their identity, elucidate their history, and prepare for a possible return to Australia. Here, we present results regarding a skull in the collection labeled as stemming from Tasmania. The non-invasive anthropological investigation revealed the skull to stem from a girl of about 15 years of age who most likely died of a massive otitis/petrositis with subsequent meningitis. These results match the historical findings, which started from an inscription on the frontal bone giving a first name ("Nanny"), an ancestry ("native of Kangaroo Island"), a collector ("Schayer"), and a location ("van Diemensland", i.e. Tasmania). The collector, Adolph Schayer, was a German sheep breeder and botanical/zoological collector living in north-western Tasmania from 1831 to 1843. In archival sources, a girl named Nanny Allan could be identified, who was a native of Kangaroo Island and died in Launceston/Tasmania in 1836 at the age of about 14 years. As there were no doubts that these remains stem from a Tasmanian individual, they were handed over to representatives of the Tasmanian Aboriginal Centre in July 2014.

Frequency comparison involving the Romanian primary length standard RO.1 within the framework of the EUROMET Project #498

NASA Astrophysics Data System (ADS)

Popescu, Gheorghe

2001-06-01

An international frequency comparison was carried out at the Bundesamt fuer Eich- und Vermessungswessen (BEV), Vienna, within the framework of the EUROMET Project #498 from August 29 to September 5, 1999. The frequency differences obtained when the RO.1 laser from the National Institute for Laser, Plasma and Radiation Physics (NILPRP), Romania, was compared with five lasers from Austria (BEV1), Czech Republic (PLD1), France (BIPM3), Poland (GUM1) and Hungary (OMH1) are reported. Frequency differences were computed by using the matrix determinations for the group d, e, f, g. Considering the frequency differences measured for a group of three lasers compared to each other, we call the closing frequency the difference between measured and expected frequency difference (resulting from the previous two measurements). For the RO1 laser, when the BIPM3 laser was the reference laser, the closing frequencies range from +8.1 kHz to - 3.8 kHz. The relative Allan standard deviation was used to express the frequency stability and resulted 3.8 parts in 1012 for 100 s sampling time and 14000 s duration of the measurements. The averaged offset frequency relative to the BIPM4 stationary laser was 5.6 kHz and the standard deviation was 9.9 kHz.

Radioactivities in returned lunar materials and in meteorites

NASA Technical Reports Server (NTRS)

Fireman, E. L.

1986-01-01

A preliminary C-14 study on lunar soil was carried out with the University of Toronto Iso Trace accelerator mass spectrometer. This accelerator was recommended for C-14 work by Dr. R. Schneider of A.S. and E., who was the field engineer during the assemblage and start-up operation of the accelerator. After the preliminary study using CO2 from 10084,937 soil, which had previously been counted with low-level mini-proportional counters, it became clear that the Toronto accelerator could carry out C-14/C-13/C-12 ratio measurements on 1 gram meteorite and lunar samples and that the C-14 measurements are done with higher precision and better reliability than elsewhere. A collaborative program with the University of Toronto Iso Trace accelerator group, which is expected to be scientifically fruitful. Arrangements have been made for Dr. R.P. Beukens of the Toronto Accelerator Group to extract the carbon compounds from Antarctic meteorite and lunar samples and to convert the compounds to CO2. During the past two years, a uranium-series dating method was developed for polar ice, which method is being applied to ice from the Allan Hills site, Byrd core, and the Beardsmore glacier.

Time-Dependent Selection of an Optimal Set of Sources to Define a Stable Celestial Reference Frame

NASA Technical Reports Server (NTRS)

Le Bail, Karine; Gordon, David

2010-01-01

Temporal statistical position stability is required for VLBI sources to define a stable Celestial Reference Frame (CRF) and has been studied in many recent papers. This study analyzes the sources from the latest realization of the International Celestial Reference Frame (ICRF2) with the Allan variance, in addition to taking into account the apparent linear motions of the sources. Focusing on the 295 defining sources shows how they are a good compromise of different criteria, such as statistical stability and sky distribution, as well as having a sufficient number of sources, despite the fact that the most stable sources of the entire ICRF2 are mostly in the Northern Hemisphere. Nevertheless, the selection of a stable set is not unique: studying different solutions (GSF005a and AUG24 from GSFC and OPA from the Paris Observatory) over different time periods (1989.5 to 2009.5 and 1999.5 to 2009.5) leads to selections that can differ in up to 20% of the sources. Observing, recording, and network improvement are some of the causes, showing better stability for the CRF over the last decade than the last twenty years. But this may also be explained by the assumption of stationarity that is not necessarily right for some sources.

Laser-based measurements of δ13 C and δ2 H methane isotope signatures: precisions competitive with mass spectrometry methods

NASA Astrophysics Data System (ADS)

Yacovitch, Tara; Shorter, Joanne; Nelson, David; Herndon, Scott; Agnese, Mike; McManus, Barry; Zahniser, Mark

2017-04-01

In order to understand how and why methane (CH4 ) concentrations change over time, it is necessary to understand their sources and sinks. Stable isotope measurements of 13 CH4 :12 CH4 and CH3 D:12 CH4 ratios constrain the inventory of these sinks and sources. Current measurements often depend on Isotope Ratio Mass Spectrometry (IRMS), which requires extensive sample preparation including cryogenic separation of methane from air and subsequent conversion to either CO2 or H2 . Here, we detail improvements to a direct-absorption laser spectrometer that enable fast and precise measurements of methane isotope ratios (δ13 C and δ2 H ) of ambient air samples, without such sample preparation. The measurement system consists of a laser-based direct absorption spectrometer configured with a sample manifold for measurement of discrete samples (as opposed to flow-through measurements). Samples are trapped in the instrument using a rapid sample switching technique that compares each flask sample against a monitor tank sample. This approach reduces instrument drift and results in excellent precision. Precisions of 0.054 o/oo for δ13 C and 1.4 o/oo for δ2 H have been achieved (Allan-Werle deviations). These results are obtained in 20 minutes using 4 replicate comparisons to a monitor tank.

CW EC-QCL-based sensor for simultaneous detection of H 2O, HDO, N 2O and CH 4 using multi-pass absorption spectroscopy

DOE PAGES

Yu, Yajun; Sanchez, Nancy P.; Griffin, Robert J.; ...

2016-05-03

A sensor system based on a continuous wave, external-cavity quantum-cascade laser (CW EC-QCL) was demonstrated for simultaneous detection of atmospheric H 2O, HDO, N 2O and CH 4 using a compact, dense pattern multi-pass gas cell with an effective path-length of 57.6 m. The EC-QCL with a mode-hop-free spectral range of 1225-1285 cm -1 operating at similar to 7.8 mu m was scanned covering four neighboring absorption lines, for H 2O at 1281.161 cm -1, HDO at 1281.455 cm -1, N 2O at 1281.53 cm -1 and CH 4 at 1281.61 cm -1. A first-harmonic-normalized wavelength modulation spectroscopy with second-harmonicmore » detection (WMS-2f/1f) strategy was employed for data processing. An Allan-Werle deviation analysis indicated that minimum detection limits of 1.77 ppmv for H 2O, 3.92 ppbv for HDO, 1.43 ppbv for N 2O, and 2.2 ppbv for CH 4 were achieved with integration times of 50-s, 50-s, 100-s and 129-s, respectively. In conclusion, experimental measurements of ambient air are also reported.« less

Measurement of the electron-impact transfer rate coefficients between the Kr(1s) states in an afterglow discharge

NASA Astrophysics Data System (ADS)

Qiu, Jie; Cheng, Zhi-Wen; Zhu, Xi-Ming; Pu, Yi-Kang

2018-04-01

The rate coefficients for the electron-impact transfer from Kr(1s5) to Kr(1s4) and from Kr(1s3) to Kr(1s2) are measured in the electron temperature (T e) range between 0.07 eV and 1 eV. In the afterglow of a capacitive krypton discharge at a fixed pressure of 20 mTorr and a peak rf power ranging from 4 to 128 W, the densities of four krypton 1s states, the electron temperature and the electron density are measured by diode laser absorption, a Langmuir probe and a microwave interferometer, respectively. With these measured quantities, the rate coefficients are obtained from a population model for krypton metastable states. The measured rate coefficients are compared with those derived from the excitation cross sections of Kr metastable states calculated by different R-matrix models. It is found that our results agree best with that from Allan et al [1]. Moreover, we analyze the assumptions made in the population model and discuss their possible impact on the accuracy of the measured rate coefficients, especially for the low T e (0.1-0.2 eV) range and a higher T e (0.4-1 eV) range.

Precise Clock Solutions Using Carrier Phase from GPS Receivers in the International GPS Service

NASA Technical Reports Server (NTRS)

Zumberge, J. F.; Jefferson, D. C.; Stowers, D. A.; Tjoelker, R. L.; Young, L. E.

1999-01-01

As one of its activities as an Analysis Center in the International GPS Service (IGS), the Jet Propulsion Laboratory (JPL) uses data from a globally distributed network of geodetic-quality GPS receivers to estimate precise clock solutions, relative to a chosen reference, for both the GPS satellites and GPS receiver internal clocks, every day. The GPS constellation and ground network provide geometrical strength resulting in formal errors of about 100 p sec for these estimates. Some of the receivers in the global IGS network contain high quality frequency references, such as hydrogen masers. The clock solutions for such receivers are smooth at the 20-p sec level on time scales of a few minutes. There are occasional (daily to weekly) shifts at the microsec level, symptomatic of receiver resets, and 200-p sec-level discontinuities at midnight due to 1-day processing boundaries. Relative clock solutions among 22 IGS sites proposed as "fiducial" in the IGS/BIPM pilot project have been examined over a recent 4-week period. This allows a quantitative measure of receiver reset frequency as a function of site. For days and-sites without resets, the Allan deviation of the relative clock solutions is also computed for subdaily values of tau..

Development a low-cost carbon monoxide sensor using homemade CW-DFB QCL and board-level electronics

NASA Astrophysics Data System (ADS)

Dang, Jingmin; Yu, Haiye; Zheng, Chuantao; Wang, Lijun; Sui, Yuanyuan; Wang, Yiding

2018-05-01

A mid-infrared sensor was demonstrated for the detection of carbon monoxide (CO) at trace level. In order to reduce cost, a homemade continuous-wave mode distributed feedback quantum cascade laser (CW-DFB QCL), a mini gas cell with 1.6-m optical length, and some self-development electronic modules were adopted as excitation source, absorption pool, and signal controlling and processing tool, respectively. Wavelength modulation spectroscopy (WMS) and phase sensitive detection (PSD) techniques as well as wavelet filtering software algorithm were used to reduce the influence of light source fluctuation and system noise and to improve measurement precision and sensitivity. Under the selected P(11) absorption line located at 2099.083 cm-1, a limit of detection (LoD) of 26 parts per billion by volume (ppbv) at atmospheric pressure was achieved with a 1-s acquisition time. Allan deviation was used to characterize the long-term performance of the CO sensor, and a measurement precision of ∼3.4 ppbv was observed with an optimal integration time of ∼114 s. As a field measurement, a continuous monitoring on indoor CO concentration for a period of 24 h was conducted, which verified the reliable and robust operation of the developed sensor.

Development and Measurements of a Mid-Infrared Multi-Gas Sensor System for CO, CO₂ and CH₄ Detection.

PubMed

Dong, Ming; Zheng, Chuantao; Miao, Shuzhuo; Zhang, Yu; Du, Qiaoling; Wang, Yiding; Tittel, Frank K

2017-09-27

A multi-gas sensor system was developed that uses a single broadband light source and multiple carbon monoxide (CO), carbon dioxide (CO₂) and methane (CH₄) pyroelectric detectors by use of the time division multiplexing (TDM) technique. A stepper motor-based rotating system and a single-reflection spherical optical mirror were designed and adopted to realize and enhance multi-gas detection. Detailed measurements under static detection mode (without rotation) and dynamic mode (with rotation) were performed to study the performance of the sensor system for the three gas species. Effects of the motor rotating period on sensor performances were also investigated and a rotation speed of 0.4π rad/s was required to obtain a stable sensing performance, corresponding to a detection period of ~10 s to realize one round of detection. Based on an Allan deviation analysis, the 1 σ detection limits under static operation are 2.96, 4.54 and 2.84 parts per million in volume (ppmv) for CO, CO₂ and CH₄, respectively and the 1 σ detection limits under dynamic operations are 8.83, 8.69 and 10.29 ppmv for the three gas species, respectively. The reported sensor has potential applications in various fields requiring CO, CO₂ and CH₄ detection such as in coal mines.

Atmospheric Measurements by Ultra-Light SpEctrometer (AMULSE) Dedicated to Vertical Profile in Situ Measurements of Carbon Dioxide (CO₂) Under Weather Balloons: Instrumental Development and Field Application.

PubMed

Joly, Lilian; Maamary, Rabih; Decarpenterie, Thomas; Cousin, Julien; Dumelié, Nicolas; Chauvin, Nicolas; Legain, Dominique; Tzanos, Diane; Durry, Georges

2016-09-29

The concentration of greenhouse gases in the atmosphere plays an important role in the radiative effects in the Earth's climate system. Therefore, it is crucial to increase the number of atmospheric observations in order to quantify the natural sinks and emission sources. We report in this paper the development of a new compact lightweight spectrometer (1.8 kg) called AMULSE based on near infrared laser technology at 2.04 µm coupled to a 6-m open-path multipass cell. The measurements were made using the Wavelength Modulation Spectroscopy (WMS) technique and the spectrometer is hence dedicated to in situ measuring the vertical profiles of the CO₂ at high precision levels (σ Allan = 0.96 ppm in 1 s integration time (1σ)) and with high temporal/spatial resolution (1 Hz/5 m) using meteorological balloons. The instrument is compact, robust, cost-effective, fully autonomous, has low-power consumption, a non-intrusive probe and is plug & play. It was first calibrated and validated in the laboratory and then used for 17 successful flights up to 10 km altitude in the region Champagne-Ardenne, France in 2014. A rate of 100% of instrument recovery was validated due to the pre-localization prediction of the Météo-France based on the flight simulation software.

Interband cascade laser based mid-infrared methane sensor system using a novel electrical-domain self-adaptive direct laser absorption spectroscopy (SA-DLAS).

PubMed

Song, Fang; Zheng, Chuantao; Yan, Wanhong; Ye, Weilin; Wang, Yiding; Tittel, Frank K

2017-12-11

To suppress sensor noise with unknown statistical properties, a novel self-adaptive direct laser absorption spectroscopy (SA-DLAS) technique was proposed by incorporating a recursive, least square (RLS) self-adaptive denoising (SAD) algorithm and a 3291 nm interband cascade laser (ICL) for methane (CH 4 ) detection. Background noise was suppressed by introducing an electrical-domain noise-channel and an expectation-known-based RLS SAD algorithm. Numerical simulations and measurements were carried out to validate the function of the SA-DLAS technique by imposing low-frequency, high-frequency, White-Gaussian and hybrid noise on the ICL scan signal. Sensor calibration, stability test and dynamic response measurement were performed for the SA-DLAS sensor using standard or diluted CH 4 samples. With the intrinsic sensor noise considered only, an Allan deviation of ~43.9 ppbv with a ~6 s averaging time was obtained and it was further decreased to 6.3 ppbv with a ~240 s averaging time, through the use of self-adaptive filtering (SAF). The reported SA-DLAS technique shows enhanced sensitivity compared to a DLAS sensor using a traditional sensing architecture and filtering method. Indoor and outdoor atmospheric CH 4 measurements were conducted to validate the normal operation of the reported SA-DLAS technique.

A single-frequency Ho:YLF pulsed laser with frequency stability better than 500 kHz

NASA Astrophysics Data System (ADS)

Kucirek, P.; Meissner, A.; Nyga, S.; Mertin, J.; Höfer, M.; Hoffmann, H.-D.

2017-03-01

The spectral stability of a previously reported Ho:YLF single frequency pulsed laser oscillator emitting at 2051 nm is drastically improved by utilizing a narrow linewidth Optically Pumped Semiconductor Laser (OPSL) as a seed for the oscillator. The oscillator is pumped by a dedicated gain-switched Tm:YLF laser at 1890 nm. The ramp-and-fire method is employed for generating single frequency emission. The heterodyne technique is used to analyze the spectral properties. The laser is designed to meet a part of the specifications for future airborne or space borne LIDAR detection of CO2. Seeding with a DFB diode and with an OPSL are compared. With OPSL seeding an Allan deviation of the centroid of the spectral distribution of 38 kHz and 517 kHz over 10 seconds and 60 milliseconds of sampling time for single pulses is achieved. The spectral width is approximately 30 MHz. The oscillator emits 2 mJ pulse energy with 50 Hz pulse repetition frequency (PRF) and 20 ns pulse duration. The optical to optical efficiency of the Ho:YLF oscillator is 10 % and the beam quality is diffraction limited. To our knowledge this is the best spectral stability demonstrated to date for a Ho:YLF laser with millijoule pulse energy and nanosecond pulse duration.

Cryogenic setup for trapped ion quantum computing.

PubMed

Brandl, M F; van Mourik, M W; Postler, L; Nolf, A; Lakhmanskiy, K; Paiva, R R; Möller, S; Daniilidis, N; Häffner, H; Kaushal, V; Ruster, T; Warschburger, C; Kaufmann, H; Poschinger, U G; Schmidt-Kaler, F; Schindler, P; Monz, T; Blatt, R

2016-11-01

We report on the design of a cryogenic setup for trapped ion quantum computing containing a segmented surface electrode trap. The heat shield of our cryostat is designed to attenuate alternating magnetic field noise, resulting in 120 dB reduction of 50 Hz noise along the magnetic field axis. We combine this efficient magnetic shielding with high optical access required for single ion addressing as well as for efficient state detection by placing two lenses each with numerical aperture 0.23 inside the inner heat shield. The cryostat design incorporates vibration isolation to avoid decoherence of optical qubits due to the motion of the cryostat. We measure vibrations of the cryostat of less than ±20 nm over 2 s. In addition to the cryogenic apparatus, we describe the setup required for an operation with 40 Ca + and 88 Sr + ions. The instability of the laser manipulating the optical qubits in 40 Ca + is characterized by yielding a minimum of its Allan deviation of 2.4 ⋅ 10 -15 at 0.33 s. To evaluate the performance of the apparatus, we trapped 40 Ca + ions, obtaining a heating rate of 2.14(16) phonons/s and a Gaussian decay of the Ramsey contrast with a 1/e-time of 18.2(8) ms.

A statistical characterization of the Galileo-to-GPS inter-system bias

NASA Astrophysics Data System (ADS)

Gioia, Ciro; Borio, Daniele

2016-11-01

Global navigation satellite system operates using independent time scales and thus inter-system time offsets have to be determined to enable multi-constellation navigation solutions. GPS/Galileo inter-system bias and drift are evaluated here using different types of receivers: two mass market and two professional receivers. Moreover, three different approaches are considered for the inter-system bias determination: in the first one, the broadcast Galileo to GPS time offset is used to align GPS and Galileo time scales. In the second, the inter-system bias is included in the multi-constellation navigation solution and is estimated using the measurements available. Finally, an enhanced algorithm using constraints on the inter-system bias time evolution is proposed. The inter-system bias estimates obtained with the different approaches are analysed and their stability is experimentally evaluated using the Allan deviation. The impact of the inter-system bias on the position velocity time solution is also considered and the performance of the approaches analysed is evaluated in terms of standard deviation and mean errors for both horizontal and vertical components. From the experiments, it emerges that the inter-system bias is very stable and that the use of constraints, modelling the GPS/Galileo inter-system bias behaviour, significantly improves the performance of multi-constellation navigation.

FY 1992 Budget committed to R&D

NASA Astrophysics Data System (ADS)

Bush, Susan

President's Bush's Fiscal Year 1992 budget for research and development is clear proof of his commitment to R&D as a long-term investment for the next American century, according to D. Allan Bromley, Assistant to the President for Science and Technology and Director, Office of Science and Technology Policy. The FY 92 budget proposes to allocate $75.6 billion for research and development, an increase of $8.4billion, or 13% over the amount appropriated for FY 91. Calling it a “good budget,” Bromley revealed the specifics of research and development in the President's budget on February 4.Bromley believes that as a nation we are underinvesting in research and development,but sees the 1992 budget increases as concrete steps to address this problem. The newly organized and revitalized Federal Coordinating Council for Science, Engineering, and Technology (FCCSET)—an interagency forum of Cabinet secretaries, deputy secretaries, and the heads of independent agencies that reviews, coordinates, and helps implement federal science and technology policy-named three high-priority cross—cutting areas of R&D and organized special interagency programs in these areas. The areas are high-performance computing and communications, global change, and mathematics and science education.

The boomerang effect in electron-hydrogen molecule scattering as determined by time-dependent calculations

NASA Astrophysics Data System (ADS)

Ben-Asher, Anael; Moiseyev, Nimrod

2017-05-01

The appearance of oscillations in the energy-dependent cross sections of the vibrational excitation ν =0 →ν ≥3 of the hydrogen molecule in its electronic ground state as predicted by Mündel, Berman, and Domcke [Phys. Rev. A 32, 181 (1985)] was confirmed in the electron scattering experiments by Allan [J. Phys. B: At. Mol. Phys. 18, L451 (1985)]. These unusual structures were obtained in spite of the extremely short lifetime of H2- in its ro-vibrational states. Based on the standard (Hermitian) time-independent scattering calculations, Horáček et al. [Phys. Rev. A 73, 022701 (2006)] associated these oscillations with the boomerang effect. Here, we show the boomerang effect as developed in time, based on our time-dependent nuclear wavepacket (WP) calculations. The nuclear WP dynamics of H2- is determined using the non-Hermitian quantum mechanics (NH-QM) which enables the use of the Born-Oppenheimer approximation with complex potential energy surfaces. This NH-QM approach, which enables us the association of the nuclear WP dynamics as obtained from the complex potential energy curve of H2- with the evolution of cross section in time, can enlighten the dynamics in other scattering experiments.

The boomerang effect in electron-hydrogen molecule scattering as determined by time-dependent calculations.

PubMed

Ben-Asher, Anael; Moiseyev, Nimrod

2017-05-28

The appearance of oscillations in the energy-dependent cross sections of the vibrational excitation ν=0→ν≥3 of the hydrogen molecule in its electronic ground state as predicted by Mündel, Berman, and Domcke [Phys. Rev. A 32, 181 (1985)] was confirmed in the electron scattering experiments by Allan [J. Phys. B: At. Mol. Phys. 18, L451 (1985)]. These unusual structures were obtained in spite of the extremely short lifetime of H 2 - in its ro-vibrational states. Based on the standard (Hermitian) time-independent scattering calculations, Horáček et al. [Phys. Rev. A 73, 022701 (2006)] associated these oscillations with the boomerang effect. Here, we show the boomerang effect as developed in time, based on our time-dependent nuclear wavepacket (WP) calculations. The nuclear WP dynamics of H 2 - is determined using the non-Hermitian quantum mechanics (NH-QM) which enables the use of the Born-Oppenheimer approximation with complex potential energy surfaces. This NH-QM approach, which enables us the association of the nuclear WP dynamics as obtained from the complex potential energy curve of H 2 - with the evolution of cross section in time, can enlighten the dynamics in other scattering experiments.

An auto-locked diode laser system for precision metrology

NASA Astrophysics Data System (ADS)

Beica, H. C.; Carew, A.; Vorozcovs, A.; Dowling, P.; Pouliot, A.; Barron, B.; Kumarakrishnan, A.

2017-05-01

We present a unique external cavity diode laser system that can be auto-locked with reference to atomic and molecular spectra. The vacuum-sealed laser head design uses an interchangeable base-plate comprised of a laser diode and optical elements that can be selected for desired wavelength ranges. The feedback light to the laser diode is provided by a narrow-band interference filter, which can be tuned from outside the laser cavity to fineadjust the output wavelength in vacuum. To stabilize the laser frequency, the digital laser controller relies either on a pattern-matching algorithm stored in memory, or on first or third derivative feedback. We have used the laser systems to perform spectroscopic studies in rubidium at 780 nm, and in iodine at 633 nm. The linewidth of the 780-nm laser system was measured to be ˜500 kHz, and we present Allan deviation measurements of the beat note and the lock stability. Furthermore, we show that the laser system can be the basis for a new class of lidar transmitters in which a temperature-stabilized fiber-Bragg grating is used to generate frequency references for on-line points of the transmitter. We show that the fiber-Bragg grating spectra can be calibrated with reference to atomic transitions.

LU-HF Age and Isotope Systematics of ALH84001

NASA Technical Reports Server (NTRS)

Righter, M.; Lapen, T. J.; Brandon, A. D.; Beard, B. L.; Shafer, J. T.; Peslier, A. H.

2009-01-01

Allan Hills (ALH) 84001 is an orthopyroxenite that is unique among the Martian meteorites in having the oldest inferred crystallization age (approx..4.5 to 4.0 Gyr) [e.g., 1-6 and references therein 7]. Its ancient origin makes this stone a critical constraint on early history of Mars, in particular the evolution of different planetary crust and mantle reservoirs. However, because there is significant variability in reported crystallization ages, determination of initial isotope compositions is imprecise making assessment of planetary reservoirs difficult. Here we report a new Lu-Hf mineral isochron age, initial Hf-176/Hf-177 isotope composition, and inferred Martian mantle source compositions for ALH84001 that place constraints on longlived source reservoirs for the enriched shergottite suite of Martian meteorites including Shergotty, Zagami, NWA4468, NWA856, RBT04262, LAR06319, and Los Angeles. Sm-Nd isotope analyses are under way for the same mineral aliquots analyzed for Lu-Hf. The Lu-Hf system was utilized because Lu and Hf are both lithophile and refractory and are not easily redistributed during short-lived thermal pulses associated with shock metamorphism. Moreover, chromite has relatively modest Hf concentrations with very low Lu/Hf ratios [9] yielding tight constraints on initial Hf-176/Hf-177 isotope compositions

Design and experimental verification of a photoacoustic flow sensor using computational fluid dynamics.

PubMed

Lassen, Mikael; Balslev-Harder, David; Brusch, Anders; Pelevic, Nikola; Persijn, Stefan; Petersen, Jan C

2018-02-01

A photoacoustic (PA) sensor for fast and real-time gas sensing is demonstrated. The PA sensor is a stand-alone system controlled by a field-programmable gate array. The PA cell has been designed for flow noise immunity using computational fluid dynamics (CFD) analysis. The aim of the CFD analysis was to investigate and minimize the influence of the gas distribution and flow noise on the PA signal. PA measurements were conducted at different flow rates by exciting molecular C-H stretch vibrational bands of hexane (C 6 H 14 ) and decane (C 10 H 22 ) molecules in clean air at 2950  cm -1 (3.38 μm) with a custom-made mid-infrared interband cascade laser. We observe a (1σ, standard deviation) sensitivity of 0.4±0.1  ppb (nmol/mol) for hexane in clean air at flow rates up to 1.7 L/min, corresponding to a normalized noise equivalent absorption coefficient of 2.5×10 -9   W cm -1   Hz -1/2 , demonstrating high sensitivity and fast real-time gas analysis. An Allan deviation analysis for decane shows that the detection limit at optimum integration time is 0.25 ppbV (nmol/mol).

Vibration Noise Modeling for Measurement While Drilling System Based on FOGs

PubMed Central

Zhang, Chunxi; Wang, Lu; Gao, Shuang; Lin, Tie; Li, Xianmu

2017-01-01

Aiming to improve survey accuracy of Measurement While Drilling (MWD) based on Fiber Optic Gyroscopes (FOGs) in the long period, the external aiding sources are fused into the inertial navigation by the Kalman filter (KF) method. The KF method needs to model the inertial sensors’ noise as the system noise model. The system noise is modeled as white Gaussian noise conventionally. However, because of the vibration while drilling, the noise in gyros isn’t white Gaussian noise any more. Moreover, an incorrect noise model will degrade the accuracy of KF. This paper developed a new approach for noise modeling on the basis of dynamic Allan variance (DAVAR). In contrast to conventional white noise models, the new noise model contains both the white noise and the color noise. With this new noise model, the KF for the MWD was designed. Finally, two vibration experiments have been performed. Experimental results showed that the proposed vibration noise modeling approach significantly improved the estimated accuracies of the inertial sensor drifts. Compared the navigation results based on different noise model, with the DAVAR noise model, the position error and the toolface angle error are reduced more than 90%. The velocity error is reduced more than 65%. The azimuth error is reduced more than 50%. PMID:29039815

Fully relativistic B-spline R-matrix calculations for electron collisions with xenon

NASA Astrophysics Data System (ADS)

Bartschat, Klaus; Zatsarinny, Oleg

2009-05-01

We have applied our recently developed fully relativistic Dirac B-spline R-matrix (DBSR) code [1] to calculate electron scattering from xenon atoms. Results from a 31-state close-coupling model for the excitation function of the metastable (5p^5 6s) J=0,2 states show excellent agreement with experiment [2], thereby presenting a significant improvement over the most sophisticated previous Breit-Pauli calculations [3,4]. This allows for a detailed and reliable analysis of the resonance structure. The same model is currently being used to calculate electron-impact excitation from the metastable J=2 state. The results will be compared with recent experimental data [5] and predictions from other theoretical models [6,7]. [1] O. Zatsarinny and K. Bartschat, Phys. Rev. A 77 (2008) 062701. [2] S. J. Buckman et al., J. Phys. B 16 (1983) 4219. [3] A. N. Grum-Grzhimailo and K. Bartschat, J. Phys. B 35 (2002) 3479. [4] M. Allan et al., Phys. Rev. A 74 (2006) 030701(R). [5] R. O. Jung et al., Phys. Rev. A 72 (2005) 022723. [6] R. Srivastava et al., Phys. Rev. A 74 (2006) 012715. [7] J. Jiang et al., J. Phys. B 41 (2008) 245204.

Heavily-hydrated lithic clasts in CH chondrites and the related, metal-rich chondrites Queen Alexandra Range 94411 and Hammadah al Hamra 237

NASA Astrophysics Data System (ADS)

Greshake, A.; Krot, A. N.; Meibom, A.; Weisberg, M. K.; Zolensky, M. E.; Keil, K.

2002-02-01

Fine-grained, heavily-hydrated lithic clasts in the metal-rich (CB) chondrites Queen Alexandra Range (QUE) 94411 and Hammadah al Hamra 237 and CH chondrites, such as Patuxent Range (PAT) 91546 and Allan Hills (ALH) 85085, are mineralogically similar suggesting genetic relationship between these meteorites. These clasts contain no anhydrous silicates and consist of framboidal and platelet magnetite, prismatic sulfides (pentlandite and pyrrhotite), and Fe-Mn-Mg-bearing Ca-carbonates set in a phyllosilicate-rich matrix. Two types of phyllosilicates were identified: serpentine, with basal spacing of ?0.73 nm, and saponite, with basal spacings of about 1.1-1.2 nm. Chondrules and FeNi-metal grains in CB and CH chondrites are believed to have formed at high temperature (>1300 K) by condensation in a solar nebula region that experienced complete vaporization. The absence of aqueous alteration of chondrules and metal grains in CB and CH chondrites indicates that the clasts experienced hydration in an asteroidal setting prior to incorporation into the CH and CB parent bodies. The hydrated clasts were either incorporated during regolith gardening or accreted together with chondrules and FeNi-metal grains after these high-temperature components had been transported from their hot formation region to a much colder region of the solar nebula.

Variation of Radiation Belt Content Indices and total electron energy During Magnetic Storms Based On Van Allen Probe Observations

NASA Astrophysics Data System (ADS)

Xiong, Y.; Xie, L.; Chen, L.; Pu, Z.

2017-12-01

We investigate the variability of the RBC indices and total electron energy for varying energies within outer belt during 42 isolate magnetic storms based on the electron flux data from MagEIS and REPT onboard Van Allen Probe-A spacecraft. Van Allan Probes travel throughout the entire radiation belt twice during each orbit, providing an excellent opportunity to measure the electron's pitch angle distributions near the magnetic equatorial plane which is essential to calculate the RBC index accurately. Instead of assuming an isotropic electron pitch angle distribution which is widely used in previous studies, we develop a new and reliable technique to infer the equatorial pitch angle distributions based on the off-equator measurements. The statistic results show that the total electron energy in outer belt increase in 80% storms and has a positive correlation with median value of AE during recovery phase and minimum -Dst. The possibility of observing RBC depletion increase at high energies. The upper limit energy of RBC enhancement has a positive correlation with median value of AE and Vsw during recovery phase and a negative correlation with median value of Nsw during storm, which is consist of the balance of acceleration by chorus waves and loss by EMIC waves.

Vibration Noise Modeling for Measurement While Drilling System Based on FOGs.

PubMed

Zhang, Chunxi; Wang, Lu; Gao, Shuang; Lin, Tie; Li, Xianmu

2017-10-17

Aiming to improve survey accuracy of Measurement While Drilling (MWD) based on Fiber Optic Gyroscopes (FOGs) in the long period, the external aiding sources are fused into the inertial navigation by the Kalman filter (KF) method. The KF method needs to model the inertial sensors' noise as the system noise model. The system noise is modeled as white Gaussian noise conventionally. However, because of the vibration while drilling, the noise in gyros isn't white Gaussian noise any more. Moreover, an incorrect noise model will degrade the accuracy of KF. This paper developed a new approach for noise modeling on the basis of dynamic Allan variance (DAVAR). In contrast to conventional white noise models, the new noise model contains both the white noise and the color noise. With this new noise model, the KF for the MWD was designed. Finally, two vibration experiments have been performed. Experimental results showed that the proposed vibration noise modeling approach significantly improved the estimated accuracies of the inertial sensor drifts. Compared the navigation results based on different noise model, with the DAVAR noise model, the position error and the toolface angle error are reduced more than 90%. The velocity error is reduced more than 65%. The azimuth error is reduced more than 50%.

Emulating JWST Exoplanet Transit Observations in a Testbed laboratory experiment

NASA Astrophysics Data System (ADS)

Touli, D.; Beichman, C. A.; Vasisht, G.; Smith, R.; Krist, J. E.

2014-12-01

observing sequences, we obtain time series photometry with deliberate offsets introduced to test sensitivity to pointing jitter and other effects. We can modify the star-planet brightness contrast by factors up to 10^4:1. With cross correlation techniques we calculate positional shifts which are then used to decorrelate the effects of vertical and lateral offsets due to turbulence and instrumental vibrations on the photometry. Using Principal Component Analysis (PCA), we reject correlated temporal noise to achieve a precision lower than 50 ppm (Clanton et al. 2012). In our current work, after decorrelation of vertical and lateral offsets along with PCA, we achieve a precision of sim20 ppm. To assess the photometric precision we use the Allan variance (Allan 1987). This statistical method is used to characterize noise and stability as it indicates shot noise limited performance. Testbed experiments are ongoing to provide quantitative information on the achievable spectroscopic precision using realistic exoplanet spectra with the goal to define optimized data acquisition sequences for use, for example, with the James Webb Space Telescope.

A new method for large-scale assessment of change in ecosystem functioning in relation to land degradation

NASA Astrophysics Data System (ADS)

Horion, Stephanie; Ivits, Eva; Verzandvoort, Simone; Fensholt, Rasmus

2017-04-01

Ongoing pressures on European land are manifold with extreme climate events and non-sustainable use of land resources being amongst the most important drivers altering the functioning of the ecosystems. The protection and conservation of European natural capital is one of the key objectives of the 7th Environmental Action Plan (EAP). The EAP stipulates that European land must be managed in a sustainable way by 2020 and the UN Sustainable development goals define a Land Degradation Neutral world as one of the targets. This implies that land degradation (LD) assessment of European ecosystems must be performed repeatedly allowing for the assessment of the current state of LD as well as changes compared to a baseline adopted by the UNCCD for the objective of land degradation neutrality. However, scientifically robust methods are still lacking for large-scale assessment of LD and repeated consistent mapping of the state of terrestrial ecosystems. Historical land degradation assessments based on various methods exist, but methods are generally non-replicable or difficult to apply at continental scale (Allan et al. 2007). The current lack of research methods applicable at large spatial scales is notably caused by the non-robust definition of LD, the scarcity of field data on LD, as well as the complex inter-play of the processes driving LD (Vogt et al., 2011). Moreover, the link between LD and changes in land use (how land use changes relates to change in vegetation productivity and ecosystem functioning) is not straightforward. In this study we used the segmented trend method developed by Horion et al. (2016) for large-scale systematic assessment of hotspots of change in ecosystem functioning in relation to LD. This method alleviates shortcomings of widely used linear trend model that does not account for abrupt change, nor adequately captures the actual changes in ecosystem functioning (de Jong et al. 2013; Horion et al. 2016). Here we present a new methodology for

Gas phase emissions from cooking processes and their secondary aerosol production potential

NASA Astrophysics Data System (ADS)

Klein, Felix; Platt, Stephen; Bruns, Emily; Termime-roussel, Brice; Detournay, Anais; Mohr, Claudia; Crippa, Monica; Slowik, Jay; Marchand, Nicolas; Baltensperger, Urs; Prevot, Andre; El Haddad, Imad

2014-05-01

Long before the industrial evolution and the era of fossil fuels, high concentrations of aerosol particles were alluded to in heavily populated areas, including ancient Rome and medieval London. Recent radiocarbon measurements (14C) conducted in modern megacities came as a surprise: carbonaceous aerosol (mainly organic aerosol, OA), a predominant fraction of particulate matter (PM), remains overwhelmingly non-fossil despite extensive fossil fuel combustion. Such particles are directly emitted (primary OA, POA) or formed in-situ in the atmosphere (secondary OA, SOA) via photochemical reactions of volatile organic compounds (VOCs). Urban levels of non-fossil OA greatly exceed the levels measured in pristine environments strongly impacted by biogenic emissions, suggesting a contribution from unidentified anthropogenic non-fossil sources to urban OA. Positive matrix factorization (PMF) techniques applied to ambient aerosol mass spectrometer (AMS, Aerodyne) data identify primary cooking emissions (COA) as one of the main sources of primary non-fossil OA in major cities like London (Allan et al., 2010), New York (Sun et al., 2011) and Beijing (Huang et al., 2010). Cooking processes can also emit VOCs that can act as SOA precursors, potentially explaining in part the high levels of oxygenated OA (OOA) identified by the AMS in urban areas. However, at present, the chemical nature of these VOCs and their secondary aerosol production potential (SAPP) remain virtually unknown. The approach adopted here involves laboratory quantification of PM and VOC emission factors from the main primary COA emitting processes and their SAPP. Primary emissions from deep-fat frying, vegetable boiling, vegetable frying and meat cooking for different oils, meats and vegetables were analysed under controlled conditions after ~100 times dilution. A high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and a high resolution proton transfer time-of-flight mass spectrometer (PTR

A short history of pediatric endocrinology in North America.

PubMed

Fisher, Delbert A

2004-04-01

Pediatric endocrinology evolved as a subspecialty from the era of biochemical and metabolic clinical investigation led by John Howland, Edwards Park, and James Gamble at Johns Hopkins; Allan Butler at Boston University and Harvard University; Daniel Darrow at Yale University; and Irving McQuarrie at the University of Rochester and the University of Minnesota during the early 20th century. The father of the new subspecialty was Lawson Wilkins, a private pediatric practitioner in Baltimore, Maryland, who was invited by Dr. Edwards Park to establish an endocrine clinic at the Harriet Lane Home at Johns Hopkins in 1935. Dr. Wilkins managed his practice and the clinic until 1946, when, at the age of 52, he accepted a full-time position at the University. Dr. Nathan Talbot was invited to develop a pediatric endocrine clinic at Massachusetts General Hospital by Allan Butler in 1942. These units and their associated subspecialty training programs during the 1950s and 1960s provided the large majority of the second-generation pediatric endocrinologists who went on to establish endocrine subspecialty programs in university medical centers in North America as well as Europe and South America. Diabetes as a clinical pediatric discipline evolved in parallel from the early clinics of Elliott Joslin and Priscilla White in Boston, M.C. Hardin and Robert Jackson at the University of Iowa, George Guest at the University of Cincinnati Children's Hospital, and Alex Hartman at the St. Louis Children's Hospital. The Lawson Wilkins Pediatric Endocrine Society was founded in 1971, and the Council on Diabetes and Youth was established within the American Diabetes Association in 1980. Medical and economic factors led to increasing integration of pediatric diabetes and general endocrine care and training, and diabetes care now is a major activity within the subspecialty of pediatric endocrinology. The growth of pediatric endocrinology in North America has paralleled the growth of academic

Picosecond-precision multichannel autonomous time and frequency counter

NASA Astrophysics Data System (ADS)

Szplet, R.; Kwiatkowski, P.; RóŻyc, K.; Jachna, Z.; Sondej, T.

2017-12-01

This paper presents the design, implementation, and test results of a multichannel time interval and frequency counter developed as a desktop instrument. The counter contains four main functional modules for (1) performing precise measurements, (2) controlling and fast data processing, (3) low-noise power suppling, and (4) supplying a stable reference clock (optional rubidium standard). A fundamental for the counter, the time interval measurement is based on time stamping combined with a period counting and in-period two-stage time interpolation that allows us to achieve wide measurement range (above 1 h), high precision (even better than 4.5 ps), and high measurement speed (up to 91.2 × 106 timestamps/s). The frequency is measured up to 3.0 GHz with the use of the reciprocal method. Wide functionality of the counter includes also the evaluation of frequency stability of clocks and oscillators (Allan deviation) and phase variation (time interval error, maximum time interval error, time deviation). The 8-channel measurement module is based on a field programmable gate array device, while the control unit involves a microcontroller with a high performance ARM-Cortex core. An efficient and user-friendly control of the counter is provided either locally, through the built-in keypad or/and color touch panel, or remotely, with the aid of USB, Ethernet, RS232C, or RS485 interfaces.

Picosecond-precision multichannel autonomous time and frequency counter.

PubMed

Szplet, R; Kwiatkowski, P; Różyc, K; Jachna, Z; Sondej, T

2017-12-01

This paper presents the design, implementation, and test results of a multichannel time interval and frequency counter developed as a desktop instrument. The counter contains four main functional modules for (1) performing precise measurements, (2) controlling and fast data processing, (3) low-noise power suppling, and (4) supplying a stable reference clock (optional rubidium standard). A fundamental for the counter, the time interval measurement is based on time stamping combined with a period counting and in-period two-stage time interpolation that allows us to achieve wide measurement range (above 1 h), high precision (even better than 4.5 ps), and high measurement speed (up to 91.2 × 10 6 timestamps/s). The frequency is measured up to 3.0 GHz with the use of the reciprocal method. Wide functionality of the counter includes also the evaluation of frequency stability of clocks and oscillators (Allan deviation) and phase variation (time interval error, maximum time interval error, time deviation). The 8-channel measurement module is based on a field programmable gate array device, while the control unit involves a microcontroller with a high performance ARM-Cortex core. An efficient and user-friendly control of the counter is provided either locally, through the built-in keypad or/and color touch panel, or remotely, with the aid of USB, Ethernet, RS232C, or RS485 interfaces.

Breakthroughs in the biogeochemistry of Nordic aquatic systems: Lessons from Water's Journey from Rain to Stream

NASA Astrophysics Data System (ADS)

Bishop, Kevin

2015-04-01

A sustainable society has been said to require knowledge of the limits placed by nature. Whatever one's views on the know-ability and significance of such limits, science strives to improve our understanding of these limiting factors, of which water is recognized to be one of the most important. Despite the centrality of water, the water cycle is maddeningly difficulty to pin down with the level of detail that is desired for resolving issues about the fate of pollutants, nutrient cycling and the global carbon balance, etc. But there is hope lurking in the Swedish landscape. The simplicity of hydrology in many Fennoscandian till soils, combined with applications of the only true tracers of water (isotopes of the water molecule) that were pioneered by Uppsala University hydrologists -provide a hydrological basis for breakthroughs in the biogeochemistry of critical earth support systems. This talk will explore some recent advances in understanding both pollutants and natural cycles, with linkages back to the concepts presented in the Water's Journey from Rain to Stream by Harald Grip and Allan Rodhe. The examples will include the mercury, acidity, and biogenic carbon of relevance to the "aquatic conduit" in the global carbon cycle. The talk will finish with thoughts about where to go next with the power that a well-characterized hydrology can provide.

Development and Measurements of a Mid-Infrared Multi-Gas Sensor System for CO, CO2 and CH4 Detection

PubMed Central

Dong, Ming; Zheng, Chuantao; Miao, Shuzhuo; Zhang, Yu; Du, Qiaoling; Wang, Yiding

2017-01-01

A multi-gas sensor system was developed that uses a single broadband light source and multiple carbon monoxide (CO), carbon dioxide (CO2) and methane (CH4) pyroelectric detectors by use of the time division multiplexing (TDM) technique. A stepper motor-based rotating system and a single-reflection spherical optical mirror were designed and adopted to realize and enhance multi-gas detection. Detailed measurements under static detection mode (without rotation) and dynamic mode (with rotation) were performed to study the performance of the sensor system for the three gas species. Effects of the motor rotating period on sensor performances were also investigated and a rotation speed of 0.4π rad/s was required to obtain a stable sensing performance, corresponding to a detection period of ~10 s to realize one round of detection. Based on an Allan deviation analysis, the 1σ detection limits under static operation are 2.96, 4.54 and 2.84 parts per million in volume (ppmv) for CO, CO2 and CH4, respectively and the 1σ detection limits under dynamic operations are 8.83, 8.69 and 10.29 ppmv for the three gas species, respectively. The reported sensor has potential applications in various fields requiring CO, CO2 and CH4 detection such as in coal mines. PMID:28953260

Monte Carlo simulations of the impact of troposphere, clock and measurement errors on the repeatability of VLBI positions

NASA Astrophysics Data System (ADS)

Pany, A.; Böhm, J.; MacMillan, D.; Schuh, H.; Nilsson, T.; Wresnik, J.

2011-01-01

Within the International VLBI Service for Geodesy and Astrometry (IVS) Monte Carlo simulations have been carried out to design the next generation VLBI system ("VLBI2010"). Simulated VLBI observables were generated taking into account the three most important stochastic error sources in VLBI, i.e. wet troposphere delay, station clock, and measurement error. Based on realistic physical properties of the troposphere and clocks we ran simulations to investigate the influence of the troposphere on VLBI analyses, and to gain information about the role of clock performance and measurement errors of the receiving system in the process of reaching VLBI2010's goal of mm position accuracy on a global scale. Our simulations confirm that the wet troposphere delay is the most important of these three error sources. We did not observe significant improvement of geodetic parameters if the clocks were simulated with an Allan standard deviation better than 1 × 10-14 at 50 min and found the impact of measurement errors to be relatively small compared with the impact of the troposphere. Along with simulations to test different network sizes, scheduling strategies, and antenna slew rates these studies were used as a basis for the definition and specification of VLBI2010 antennas and recording system and might also be an example for other space geodetic techniques.

Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

NASA Astrophysics Data System (ADS)

Jones, D. B.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

2016-04-01

We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

Double closed-loop control of integrated optical resonance gyroscope with mean-square exponential stability.

PubMed

Li, Hui; Liu, Liying; Lin, Zhili; Wang, Qiwei; Wang, Xiao; Feng, Lishuang

2018-01-22

A new double closed-loop control system with mean-square exponential stability is firstly proposed to optimize the detection accuracy and dynamic response characteristic of the integrated optical resonance gyroscope (IORG). The influence mechanism of optical nonlinear effects on system detection sensitivity is investigated to optimize the demodulation gain, the maximum sensitivity and the linear work region of a gyro system. Especially, we analyze the effect of optical parameter fluctuation on the parameter uncertainty of system, and investigate the influence principle of laser locking-frequency noise on the closed-loop detection accuracy of angular velocity. The stochastic disturbance model of double closed-loop IORG is established that takes the unfavorable factors such as optical effect nonlinearity, disturbed disturbance, optical parameter fluctuation and unavoidable system noise into consideration. A robust control algorithm is also designed to guarantee the mean-square exponential stability of system with a prescribed H ∞ performance in order to improve the detection accuracy and dynamic performance of IORG. The conducted experiment results demonstrate that the IORG has a dynamic response time less than 76us, a long-term bias stability 7.04°/h with an integration time of 10s over one-hour test, and the corresponding bias stability 1.841°/h based on Allan deviation, which validate the effectiveness and usefulness of the proposed detection scheme.

Educating science teachers for sustainability: questions, contradictions and possibilities for rethinking learning and pedagogy

NASA Astrophysics Data System (ADS)

Rahm, Jrène; Gorges, Anna

2017-09-01

In this review, we explore what educating science teachers for sustainability implies according to the 23 book chapters and many sampled teacher education and science methods courses in the edited book by Susan Stratton, Rita Hagevick, Allan Feldman and Mark Bloom, entitled Educating Science Teachers for Sustainability, published in 2015 by Springer as part of the ASTE Series in Science Education. We situate the review in the current complex landscape of discourses around sustainability education, exploring its grounding in an anthropocentric ideology next to emancipatory practices and a holistic vision of the world. We offer a quick overview of the chapters and themes addressed. We then take up some ideas to think with. We are particularly invested in thinking about the implications of sustainability education as going beyond science teachers and science education, and as implying a serious engagement with and critique of current unsustainable ways of living. We play with the idea of taking sustainability education beyond neoliberal ideals of education and offer some suggestions by bringing in voices of students, youth, land-based learning and the idea of living sustainability. We also explore what indigenous scholars and epistemologies could have contributed to an exploration of sustainability education, a voice that was absent in the book, yet helps desettle the conversation and actions taken, moving the discourse beyond an Eurocentric grounding.