Sample records for rapid acquisition gradient

  1. JIEDDO Experience Provides Rapid Acquisition Insights

    National Research Council Canada - National Science Library

    James P Craft


    .... JIDA's rapid acquisition capabilities were preserved by transitioning the expedient organization that received supplemental funding into the Defense Department's newest combat support agency (CSA...

  2. Utilizing Information Technology to Facilitate Rapid Acquisition (United States)


    ordering systems to facilitate streamlined commercial item acquisitions that reap the benefits of improved efficiency, reduced overall costs, and...PAGES 109 14. SUBJECT TERMS Rapid Acquisition, eCommerce , eProcurement, Information Technology, Contracting, Global Information Network...streamlined commercial item acquisitions that reap the benefits of improved efficiency, reduced overall costs, and timeliness. This thesis

  3. Organizational Design for USSOCOM Rapid Acquisition (United States)


    2 Ibid., 249. 25 of the programs.3 In rapid innovation , it is important for Program Executive Officers to ensure that technical...organizational learning is what the company does in order to create innovative products and survive. They note that, “interviewees emphasized the importance ...14. ABSTRACT USSOCOM Special Operations Forces (SOF) Acquisition, Technology and Logistics (AT&L) struggles to keep pace with technology innovation

  4. Shuffled magnetization-prepared multicontrast rapid gradient-echo imaging. (United States)

    Cao, Peng; Zhu, Xucheng; Tang, Shuyu; Leynes, Andrew; Jakary, Angela; Larson, Peder E Z


    To develop a novel acquisition and reconstruction method for magnetization-prepared 3-dimensional multicontrast rapid gradient-echo imaging, using Hankel matrix completion in combination with compressed sensing and parallel imaging. A random k-space shuffling strategy was implemented in simulation and in vivo human experiments at 7 T for 3-dimensional inversion recovery, T2 /diffusion preparation, and magnetization transfer imaging. We combined compressed sensing, based on total variation and spatial-temporal low-rank regularizations, and parallel imaging with pixel-wise Hankel matrix completion, allowing the reconstruction of tens of multicontrast 3-dimensional images from 3- or 6-min scans. The simulation result showed that the proposed method can reconstruct signal-recovery curves in each voxel and was robust for typical in vivo signal-to-noise ratio with 16-times acceleration. In vivo studies achieved 4 to 24 times accelerations for inversion recovery, T2 /diffusion preparation, and magnetization transfer imaging. Furthermore, the contrast was improved by resolving pixel-wise signal-recovery curves after magnetization preparation. The proposed method can improve acquisition efficiencies for magnetization-prepared MRI and tens of multicontrast 3-dimensional images could be recovered from a single scan. Furthermore, it was robust against noise, applicable for recovering multi-exponential signals, and did not require any previous knowledge of model parameters. Magn Reson Med 79:62-70, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  5. Literacy acquisition influences children's rapid automatized naming. (United States)

    Peterson, Robin L; Arnett, Anne B; Pennington, Bruce F; Byrne, Brian; Samuelsson, Stefan; Olson, Richard K


    Previous research has established that learning to read improves children's performance on reading-related phonological tasks, including phoneme awareness (PA) and nonword repetition. Few studies have investigated whether literacy acquisition also promotes children's rapid automatized naming (RAN). We tested the hypothesis that literacy acquisition should influence RAN in an international, longitudinal population sample of twins. Cross-lagged path models evaluated the relationships among literacy, PA, and RAN across four time points from pre-kindergarten through grade 4. Consistent with previous research, literacy showed bidirectional relationships with reading-related oral language skills. We found novel evidence for an effect of earlier literacy on later RAN, which was most evident in children at early phases of literacy development. In contrast, the influence of earlier RAN on later literacy was predominant among older children. These findings imply that the association between these two related skills is moderated by development. Implications for models of reading development and for dyslexia research are discussed. © 2017 John Wiley & Sons Ltd.

  6. A rapid and robust gradient measurement technique using dynamic single-point imaging. (United States)

    Jang, Hyungseok; McMillan, Alan B


    We propose a new gradient measurement technique based on dynamic single-point imaging (SPI), which allows simple, rapid, and robust measurement of k-space trajectory. To enable gradient measurement, we utilize the variable field-of-view (FOV) property of dynamic SPI, which is dependent on gradient shape. First, one-dimensional (1D) dynamic SPI data are acquired from a targeted gradient axis, and then relative FOV scaling factors between 1D images or k-spaces at varying encoding times are found. These relative scaling factors are the relative k-space position that can be used for image reconstruction. The gradient measurement technique also can be used to estimate the gradient impulse response function for reproducible gradient estimation as a linear time invariant system. The proposed measurement technique was used to improve reconstructed image quality in 3D ultrashort echo, 2D spiral, and multi-echo bipolar gradient-echo imaging. In multi-echo bipolar gradient-echo imaging, measurement of the k-space trajectory allowed the use of a ramp-sampled trajectory for improved acquisition speed (approximately 30%) and more accurate quantitative fat and water separation in a phantom. The proposed dynamic SPI-based method allows fast k-space trajectory measurement with a simple implementation and no additional hardware for improved image quality. Magn Reson Med 78:950-962, 2017. © 2016 International Society for Magnetic Resonance in Medicine. © 2016 International Society for Magnetic Resonance in Medicine.

  7. Analysis of Rapid Acquisition Processes to Fulfill Future Urgent Needs (United States)


    UAVs , the DOD defines UAVs as “powered aerial vehicle that does not carry a human operator; use aerodynamic forces to provide lift; can be autonomously...25 B. UAV ...25 1. UAV Background ...............................................................................25 2. Rapid Acquisition in UAV

  8. MR sequences and rapid acquisition for MR guided interventions (United States)

    Campbell-Washburn, Adrienne E; Faranesh, Anthony Z; Lederman, Robert J; Hansen, Michael S


    Synopsis Interventional MR uses rapid imaging to guide diagnostic and therapeutic procedures. One of the attractions of MR-guidance is the abundance of inherent contrast mechanisms available. Dynamic procedural guidance with real-time imaging has pushed the limits of MR technology, demanding rapid acquisition and reconstruction paired with interactive control and device visualization. This article reviews the technical aspects of real-time MR sequences that enable MR-guided interventions. PMID:26499283

  9. T1rho-prepared balanced gradient echo for rapid 3D T1rho MRI. (United States)

    Witschey, Walter R T; Borthakur, Arijitt; Elliott, Mark A; Fenty, Matthew; Sochor, Matthew A; Wang, Chenyang; Reddy, Ravinder


    To develop a T1rho-prepared, balanced gradient echo (b-GRE) pulse sequence for rapid three-dimensional (3D) T1rho relaxation mapping within the time constraints of a clinical exam (prepared, fat saturation, T1rho-preparation, and b-GRE image acquisition was used to obtain 3D volume coverage of the patellofemoral and tibiofemoral cartilage and lower lumbar spine. Multiple T1rho-weighted images at various contrast times (spin-lock pulse duration [TSL]) were used to construct a T1rho relaxation map in both phantoms and in the knee joint and spine in vivo. The transient signal decay during b-GRE image acquisition was corrected using a k-space filter. The T1rho-prepared b-GRE sequence was compared to a standard T1rho-prepared spin echo (SE) sequence and pulse sequence parameters were optimized numerically using the Bloch equations. The b-GRE transient signal decay was found to depend on the initial T1rho-preparation and the corresponding T1rho map was altered by variations in the point spread function with TSL. In a two compartment phantom, the steady state response was found to elevate T1rho from 91.4+/-6.5 to 293.8+/-31 and 66.9+/-3.5 to 661+/-207 with no change in the goodness-of-fit parameter R2. Phase encoding along the longest cartilage dimension and a transient signal decay k-space filter retained T1rho contrast. Measurement of T1rho using the T1rho-prepared b-GRE sequence matches standard T1rho-prepared SE in the medial patellar and lateral patellar cartilage compartments. T1rho-preparedb-GRE T1rho was found to have low interscan variability between four separate scans. Mean patellar cartilage T1rho was elevated compared to femoral and tibial cartilage T1rho. The T1rho-prepared b-GRE acquisition rapidly and reliably accelerates T1rho quantification of tissues offset partially by a TSL-dependent point spread function. Copyright (c) 2008 Wiley-Liss, Inc.

  10. Rapid chemical shift encoding with single-acquisition single-slab 3D GRASE. (United States)

    Kim, Hahnsung; Kim, Dong-Hyun; Sohn, Chul-Ho; Park, Jaeseok


    To investigate the feasibility of chemical shift encoded, single-slab 3D GRASE for rapid fat-water separation within a single acquisition. The proposed method incorporates signal-to-noise-ratio-optimal chemical shift encoding into single-slab 3D GRASE with variable flip angles. Chemical shift induced phase information was encoded in succession to different positions in k-space by inserting phase encoding blips between adjacent lobes of the oscillating readout gradients. To enhance imaging efficiency, signal prescription-based variable flip angles were used in the long refocusing pulse train. After echo-independent phase correction, missing signals in k-echo space were interpolated using convolution kernels that span over all echoes. Fat-water separation in a single acquisition was performed using both multi-echo fast spin echo and GRASE as compared to conventional multiacquisition fast spin echo with echo shifts. The proposed single-slab 3D GRASE shows superior performance in accurately delineating cartilage structures compared to its counterpart, multi-echo 3D fast spin echo. Compared with multiacquisition fast spin echo with three echo shifts (63 min), the proposed method substantially speeds up imaging time (7 min), and achieves 0.6 mm isotropic resolution in knee imaging with reduced artifacts and noise. We successfully demonstrated the feasibility of rapid chemical shift encoding and separation using the proposed, single-acquisition single-slab 3D GRASE for high resolution isotropic imaging within clinically acceptable time. Magn Reson Med 78:1852-1861, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  11. SPRAT: Spectrograph for the Rapid Acquisition of Transients (United States)

    Piascik, A. S.; Steele, Iain A.; Bates, Stuart D.; Mottram, Christopher J.; Smith, R. J.; Barnsley, R. M.; Bolton, B.


    We describe the development of a low cost, low resolution (R ~ 350), high throughput, long slit spectrograph covering visible (4000-8000) wavelengths. The spectrograph has been developed for fully robotic operation with the Liverpool Telescope (La Palma). The primary aim is to provide rapid spectral classification of faint (V ˜ 20) transient objects detected by projects such as Gaia, iPTF (intermediate Palomar Transient Factory), LOFAR, and a variety of high energy satellites. The design employs a volume phase holographic (VPH) transmission grating as the dispersive element combined with a prism pair (grism) in a linear optical path. One of two peak spectral sensitivities are selectable by rotating the grism. The VPH and prism combination and entrance slit are deployable, and when removed from the beam allow the collimator/camera pair to re-image the target field onto the detector. This mode of operation provides automatic acquisition of the target onto the slit prior to spectrographic observation through World Coordinate System fitting. The selection and characterisation of optical components to maximise photon throughput is described together with performance predictions.

  12. Imperfect Acquisition of a Related Variety? Residual Clefting and What It Reveals about (Gradient Bilectalism

    Directory of Open Access Journals (Sweden)

    Stavroula Tsiplakou


    Full Text Available This article explores the concept of gradient bilectalism by capitalizing on insights from recent developments in second language acquisition, particularly the suggestion that aspects of the syntax–discourse interface that are not easily accessible to the learner may lead to fossilization, even at end state. I explore the implications of this suggestion for bilectal grammars by examining the ways in which speakers of Cypriot Greek do syntactic focusing in Standard Greek. The phenomenon is structurally different in the two varieties of Greek examined: clefting is the Cypriot syntactic focusing strategy par excellence while in Standard Greek the relevant strategy is movement of the focused item to an immediately preverbal position. Interestingly, this focusing strategy is largely unattested in the acrolectal or standard-like production of bilectal Greek Cypriot speakers; on the contrary, the preferred strategy for syntactic focusing appears to be clefting, as is indicated by data from spontaneous speech. Quantitative data from a questionnaire survey presented in this article confirm that such “residual clefting” persists even at end state, which in turn suggests imperfect acquisition of the relevant structural aspect of Standard Greek, the second variety of these otherwise bilectal speakers. The data invite an approach couched within the Interface Hypothesis, and the argument is put forward that, being a structure at the interface between syntax and other modules or cognitive domains (semantics, pragmatics, and discourse, focusing in the target variety is vulnerable as regards acquisition.

  13. An Analysis of Test And Evaluation in Rapid Acquisition Programs (United States)


    Outfits DT Developmental Testing DT&E Development Test and Evaluation DTC Developmental Test Command E3 Electromagnetic Environmental the OEM and evaluated by the Communication-Electronics Command (CECOM) Safety Office and the former Developmental Test Command ( DTC ) covering all...Force Management School AMC Army Materiel Command AOA Analysis of Alternatives AOR Area of Operation APC Acquisition Program Candidates APG Aberdeen

  14. Is Sordac’s Rapid Acquisition Process Best Prepared To Field Solutions For Future Technological Challenges (United States)


    views expressed in this academic research paper are those of the author and do not reflect the official policy or position of the US government, the...SORDAC) is the Department of Defense (DoD) leader in rapid acquisitions, and its culture and practices should be benchmarked by the other services. This...should be benchmarked by all other services. This essay first examines SORDAC’s acquisition environment and assesses SORDAC’s unique culture. This

  15. Rapid Learning of an Abstract Language-Specific Category: Polish Children's Acquisition of the Instrumental Construction (United States)

    Dabrowska, Ewa; Tomasello, Michael


    Rapid acquisition of linguistic categories or constructions is sometimes regarded as evidence of innate knowledge. In this paper, we examine Polish children's early understanding of an idiosyncratic, language-specific construction involving the instrumental case--which could not be due to innate knowledge. Thirty Polish-speaking children aged 2; 6…

  16. A tissue-scale gradient of hydrogen peroxide mediates rapid wound detection in zebrafish. (United States)

    Niethammer, Philipp; Grabher, Clemens; Look, A Thomas; Mitchison, Timothy J


    Barrier structures (for example, epithelia around tissues and plasma membranes around cells) are required for internal homeostasis and protection from pathogens. Wound detection and healing represent a dormant morphogenetic program that can be rapidly executed to restore barrier integrity and tissue homeostasis. In animals, initial steps include recruitment of leukocytes to the site of injury across distances of hundreds of micrometres within minutes of wounding. The spatial signals that direct this immediate tissue response are unknown. Owing to their fast diffusion and versatile biological activities, reactive oxygen species, including hydrogen peroxide (H(2)O(2)), are interesting candidates for wound-to-leukocyte signalling. Here we probe the role of H(2)O(2) during the early events of wound responses in zebrafish larvae expressing a genetically encoded H(2)O(2) sensor. This reporter revealed a sustained rise in H(2)O(2) concentration at the wound margin, starting approximately 3 min after wounding and peaking at approximately 20 min, which extended approximately 100-200 microm into the tail-fin epithelium as a decreasing concentration gradient. Using pharmacological and genetic inhibition, we show that this gradient is created by dual oxidase (Duox), and that it is required for rapid recruitment of leukocytes to the wound. This is the first observation, to our knowledge, of a tissue-scale H(2)O(2) pattern, and the first evidence that H(2)O(2) signals to leukocytes in tissues, in addition to its known antiseptic role.

  17. Self-calibrated multiple-echo acquisition with radial trajectories using the conjugate gradient method (SMART-CG). (United States)

    Jung, Youngkyoo; Samsonov, Alexey A; Bydder, Mark; Block, Walter F


    To remove phase inconsistencies between multiple echoes, an algorithm using a radial acquisition to provide inherent phase and magnitude information for self correction was developed. The information also allows simultaneous support for parallel imaging for multiple coil acquisitions. Without a separate field map acquisition, a phase estimate from each echo in multiple echo train was generated. When using a multiple channel coil, magnitude and phase estimates from each echo provide in vivo coil sensitivities. An algorithm based on the conjugate gradient method uses these estimates to simultaneously remove phase inconsistencies between echoes, and in the case of multiple coil acquisition, simultaneously provides parallel imaging benefits. The algorithm is demonstrated on single channel, multiple channel, and undersampled data. Substantial image quality improvements were demonstrated. Signal dropouts were completely removed and undersampling artifacts were well suppressed. The suggested algorithm is able to remove phase cancellation and undersampling artifacts simultaneously and to improve image quality of multiecho radial imaging, the important technique for fast three-dimensional MRI data acquisition. Copyright © 2011 Wiley-Liss, Inc.

  18. Free-space laser communication system with rapid acquisition based on astronomical telescopes. (United States)

    Wang, Jianmin; Lv, Junyi; Zhao, Guang; Wang, Gang


    The general structure of a free-space optical (FSO) communication system based on astronomical telescopes is proposed. The light path for astronomical observation and for communication can be easily switched. A separate camera is used as a star sensor to determine the pointing direction of the optical terminal's antenna. The new system exhibits rapid acquisition and is widely applicable in various astronomical telescope systems and wavelengths. We present a detailed analysis of the acquisition time, which can be decreased by one order of magnitude compared with traditional optical communication systems. Furthermore, we verify software algorithms and tracking accuracy.

  19. Rapid Delivery of Cyber Capabilities: Evaluation of the Requirement for a Rapid Cyber Acquisition Process (United States)


    capabilities and rapid implementation of tactics—all aspects readily addressed using non-material solutions. Additionally, configuration and maintenance of...Offict Symbol: 4. Co~ttac-t 1nror11tation: (l\\’am~ Pj Rcqu.-$1/.Uomtlt’nttNU POC) (RD.11J.!Crrult’) (0/ Jit ’’ Spn) Phone’ 1\\’un.rbo S. T ec:hni<’lll POC 6

  20. Knowledge acquisition and rapid protyping of an expert system: Dealing with real world problems (United States)

    Bailey, Patrick A.; Doehr, Brett B.


    The knowledge engineering and rapid prototyping phases of an expert system that does fault handling for a Solid Amine, Water Desorbed CO2 removal assembly for the Environmental Control and Life Support System for space based platforms are addressed. The knowledge acquisition phase for this project was interesting because it could not follow the textbook examples. As a result of this, a variety of methods were used during the knowledge acquisition task. The use of rapid prototyping and the need for a flexible prototype suggested certain types of knowledge representation. By combining various techniques, a representative subset of faults and a method for handling those faults was achieved. The experiences should prove useful for developing future fault handling expert systems under similar constraints.

  1. Miniaturized Antimicrobial Susceptibility Test by Combining Concentration Gradient Generation and Rapid Cell Culturing

    Directory of Open Access Journals (Sweden)

    Samuel C. Kim


    Full Text Available Effective treatment of bacterial infection relies on timely diagnosis and proper prescription of antibiotic drugs. The antimicrobial susceptibility test (AST is one of the most crucial experimental procedures, providing the baseline information for choosing effective antibiotic agents and their dosages. Conventional methods, however, require long incubation times or significant instrumentation costs to obtain test results. We propose a lab-on-a-chip approach to perform AST in a simple, economic, and rapid manner. Our assay platform miniaturizes the standard broth microdilution method on a microfluidic device (20 × 20 mm that generates an antibiotic concentration gradient and delivers antibiotic-containing culture media to eight 30-nL chambers for cell culture. When tested with 20 μL samples of a model bacterial strain (E. coli ATCC 25922 treated with ampicillin or streptomycin, our method allows for the determination of minimum inhibitory concentrations consistent with the microdilution test in three hours, which is almost a factor of ten more rapid than the standard method.

  2. Rapid Indoor Data Acquisition for Ladm-Based 3d Cadastre Model (United States)

    Jamali, A.; Boguslawski, P.; Duncan, E. E.; Gold, C. M.; Rahman, A. Abdul


    2D cadastre has been in existence for decades and most countries have found it convenient. However, in complex situations it has been found to be inadequate as ownership becomes difficult to realise. 3D cadastre data was previously not being collected, thus, making such data even more difficult to realise. 3D data collection for 3D cadastre is one of the main issues for practising surveyors. Several ways of obtaining 3D data exist namely, traditional surveying, terrestrial laser scanning and from Computer Aided Design (CAD) sources. Various data sources have different data structure and a generalized data structure for 3D cadastre hardly reported. A simple and rapid method for indoor data acquisition is proposed. This seeks to determine if the dual half edge data structure is suitable for 3D cadastre. The dual half edge data structure is applied within a graphical user interface. The concept for indoor surveying or data acquisition within the LA_SpatialUnit of the Land Administration Domain Model (LADM) is presented and proposed.

  3. A Magnetic Resonance Measurement Technique for Rapidly Switched Gradient Magnetic Fields in a Magnetic Resonance Tomograph

    Directory of Open Access Journals (Sweden)

    K. Bartušek


    Full Text Available This paper describes a method for measuring of the gradient magnetic field in Nuclear Magnetic Resonance (NMR tomography, which is one of the modern medical diagnostic methods. A very important prerequisite for high quality imaging is a gradient magnetic field in the instrument with exactly defined properties. Nuclear magnetic resonance enables us to measure the pulse gradient magnetic field characteristics with high accuracy. These interesting precise methods were designed, realised, and tested at the Institute of Scientific Instruments (ISI of the Academy of Sciences of the Czech Republic. The first of them was the Instantaneous Frequency (IF method, which was developed into the Instantaneous Frequency of Spin Echo (IFSE and the Instantaneous Frequency of Spin Echo Series (IFSES methods. The above named methods are described in this paper and their a comparison is also presented.

  4. Rapid manufacturing of polyethylene parts with controlled pore size gradients using selective laser sintering

    Directory of Open Access Journals (Sweden)

    Gean Vitor Salmoria


    Full Text Available In this study HDPE specimens were fabricated by selective laser sintering using different particle sizes to obtain controlled variations in the porosity. Electron microscopy, density measurements and mechanical analyses were conducted for the characterization of the specimens. Parts with controlled pore gradients were also manufactured and characterized. The specimens with larger particle sizes had a high sintering degree and a significant level of close pores, as shown by microscopy and density analyses. However, the mechanical properties of specimens prepared with large particles had low values due to the limited density of union points, i.e., low neck number/area. HDPE parts with pore gradients were prepared by selective laser sintering demonstrating that this technique can be used to easily control the structure and the properties of the parts manufactured. This technology may have applications in areas such as drug delivery devices and scaffolds for tissue engineering.

  5. Improving Rapid Acquisition: A Review of the Riverine Command Boat Procurement (United States)


    Management System AAC acquisition advice code ACAT acquisition category ALT administrative lead-time AMD average monthly demand APL...formal system for acquisition and follows guidelines set forth in the DoD 5000 series first released in 1971. It is a milestone-driven, low-risk...procured, materials. The Navy first issued maintenance guidelines in January 2011. The class-maintenance plan for the RCB was published in February 2013

  6. Rapid adaptive evolution of photoperiodic response during invasion and range expansion across a climatic gradient. (United States)

    Urbanski, Jennifer; Mogi, Motoyoshi; O'Donnell, Deborah; DeCotiis, Mark; Toma, Takako; Armbruster, Peter


    Abstract Understanding the mechanisms of adaptation to spatiotemporal environmental variation is a fundamental goal of evolutionary biology. This issue also has important implications for anticipating biological responses to contemporary climate warming and determining the processes by which invasive species are able to spread rapidly across broad geographic ranges. Here, we compare data from a historical study of latitudinal variation in photoperiodic response among Japanese and U.S. populations of the invasive Asian tiger mosquito Aedes albopictus with contemporary data obtained using comparable methods. Our results demonstrated rapid adaptive evolution of the photoperiodic response during invasion and range expansion across ∼15° of latitude in the United States. In contrast to the photoperiodic response, size-based morphological traits implicated in climatic adaptation in a wide range of other insects did not show evidence of adaptive variation in Ae. albopictus across either the U.S. (invasive) or Japanese (native) range. These results show that photoperiodism has been an important adaptation to climatic variation across the U.S. range of Ae. albopictus and, in conjunction with previous studies, strongly implicate the photoperiodic control of seasonal development as a critical evolutionary response to ongoing contemporary climate change. These results also emphasize that photoperiodism warrants increased attention in studies of the evolution of invasive species.


    Energy Technology Data Exchange (ETDEWEB)

    El-Badry, Kareem; Geha, Marla [Department of Astronomy, Yale University, New Haven, CT (United States); Wetzel, Andrew; Hopkins, Philip F. [TAPIR, California Institute of Technology, Pasadena, CA USA (United States); Kereš, Dusan; Chan, T. K. [Department of Physics, Center for Astrophysics and Space Sciences, University of California at San Diego, La Jolla (United States); Faucher-Giguère, Claude-André, E-mail: [Department of Physics and Astronomy and CIERA, Northwestern University, Evanston, IL (United States)


    We examine the effects of stellar feedback and bursty star formation on low-mass galaxies (M{sub star} = 2 × 10{sup 6} − 5 × 10{sup 10} M{sub ⊙}) using the Feedback in Realistic Environments (FIRE) simulations. While previous studies emphasized the impact of feedback on dark matter profiles, we investigate the impact on the stellar component: kinematics, radial migration, size evolution, and population gradients. Feedback-driven outflows/inflows drive significant radial stellar migration over both short and long timescales via two processes: (1) outflowing/infalling gas can remain star-forming, producing young stars that migrate ∼1 kpc within their first 100 Myr, and (2) gas outflows/inflows drive strong fluctuations in the global potential, transferring energy to all stars. These processes produce several dramatic effects. First, galaxies’ effective radii can fluctuate by factors of >2 over ∼200 Myr, and these rapid size fluctuations can account for much of the observed scatter in the radius at fixed M{sub star}. Second, the cumulative effects of many outflow/infall episodes steadily heat stellar orbits, causing old stars to migrate outward most strongly. This age-dependent radial migration mixes—and even inverts—intrinsic age and metallicity gradients. Thus, the galactic-archaeology approach of calculating radial star formation histories from stellar populations at z = 0 can be severely biased. These effects are strongest at M{sub star} ≈ 10{sup 7–9.6} M{sub ⊙}, the same regime where feedback most efficiently cores galaxies. Thus, detailed measurements of stellar kinematics in low-mass galaxies can strongly constrain feedback models and test baryonic solutions to small-scale problems in ΛCDM.

  8. Rapid Acquisition and Fielding for Information Assurance and Cyber Security in the Navy (United States)


    Com- mand and Control (DJC2); Norman Beebe , IA contractor handling C&A for DJC2; Leo Martinez, Booz Allen Hamilton, PEO C4I and Space Support; Marianne... Leslie , Defense Acquisition University, “Contracting in a Changing Environment,” briefing, undated. Dillard, John T., and David N. Ford, From

  9. USMC Contingency Contracting Force: An Analysis of Transient Officers in a Rapidly Changing Acquisition Environment (United States)


    customers to alleviate problems associated to requirements definition . • Contract Documentation With Contract Documentation containing 29 total reports...and skills needed to manage the department’s acquisition system” (2008, p. 268). Relating back to the CCF, an overpopulation of lieutenant colonels...questions are more broad-brushed than definitive . I graduated NPS in 2003 and with the exception of a 2-year command tour I have been in the MOS and have

  10. Optical acquisition and polar decomposition of the full-field deformation gradient tensor within a fracture callus. (United States)

    Kim, Wangdo; Kohles, Sean S


    Tracking tissue deformation is often hampered by material inhomogeneity, so local measurements tend to be insufficient thus lending to the necessity of full-field optical measurements. This study presents a novel approach to factoring heterogeneous deformation of soft and hard tissues in a fracture callus by introducing an anisotropic metric derived from the deformation gradient tensor (F). The deformation gradient tensor contains all the information available in a Green-Lagrange strain tensor, plus the rigid-body rotational components. A recent study [Bottlang et al., Journal of Biomechanics 41(3), 2008] produced full-field strains within ovine fracture calluses acquired through the application of electronic speckle pattern interferometery (ESPI). The technique is based on infinitesimal strain approximation (Engineering Strain) whose scheme is not independent of rigid-body rotation. In this work, for rotation extraction, the stretch and rotation tensors were separately determined from F by the polar decomposition theorem. Interfragmentary motions in a fracture gap were characterized by the two distinct mechanical factors (stretch and rotation) at each material point through full-field mapping. In the composite nature of bone and soft tissue, collagen arrangements are hypothesized such that fibers locally aligned with principal directions will stretch and fibers not aligned with the principal direction will rotate and stretch. This approach has revealed the deformation gradient tensor as an appropriate quantification of strain within callus bony and fibrous tissue via optical measurements.

  11. Rapid acquisition of HPV around the time of sexual debut in adolescent girls in Tanzania. (United States)

    Houlihan, Catherine F; Baisley, Kathy; Bravo, Ignacio G; Kapiga, Saidi; de Sanjosé, Silvia; Changalucha, John; Ross, David A; Hayes, Richard J; Watson-Jones, Deborah


    No reports exist on genotype-specific human papillomavirus (HPV) acquisition in girls after first sex in sub-Saharan Africa, despite high HPV prevalence and cervical cancer incidence. We followed 503 HP-unvaccinated girls aged 15-16 years in Mwanza, Tanzania, 3-monthly for 18 months with interviews and self-administered vaginal swabs. Swabs were tested for 13 higHRisk and 24 low-risk HPV genotypes. Incidence, clearance and duration of overall HPV and genotype-specific infections were calculated and associated factors evaluated. A total of 106 participants reported first sex prior to enrolment (N = 29) or during follow-up (N = 77). One was HIV-positive at the final visit. The remaining 105 girls contributed 323 adequate specimens. Incidence of any new HPV genotype was 225/100 person-years (pys), and incidence of vaccine types HPV-6, -11, -16 and -18 were 12, 2, 2 and 7/100 pys, respectively. Reporting sex in the past 3 months and knowing the most recent sexual partner for a longer period before sex were associated with HPV acquisition. Median time from reported sexual debut to first HPVinfection was 5 months, and infection duration was 6 months. This is the first description of HPV acquisition after first sex in sub-Saharan Africa where the incidence of cervical cancer is amongst the highest in the world. HPV incidence was very high after first sex, including some vaccine genotypes, and infection duration was short. This very high HPV incidence may help explain high cervical cancer rates, and supports recommendations that the HPV vaccine should be given to girls before first sex. © The Author 2016; Published by Oxford University Press on behalf of the International Epidemiological Association.

  12. Rapid acquisition of HPV around the time of sexual debut in adolescent girls in Tanzania.


    Houlihan, CF; Baisley, K; Bravo, IG; Kapiga, S; de Sanjosé, S; Changalucha, J; Ross, DA; Hayes, RJ; Watson-Jones, D


    Background: No reports exist on genotype-specific human papillomavirus (HPV) acquisition in girls after first sex in sub-Saharan Africa, despite high HPV prevalence and cervical cancer incidence. Methods: We followed 503?HP-unvaccinated girls aged 15-16 years in Mwanza, Tanzania, 3-monthly for 18 months with interviews and self-administered vaginal swabs. Swabs were tested for 13 higHRisk and 24 low-risk HPV genotypes. Incidence, clearance and duration of overall HPV and genotype-specific inf...

  13. A high-resolution optical measurement system for rapid acquisition of radiation flux density maps (United States)

    Thelen, Martin; Raeder, Christian; Willsch, Christian; Dibowski, Gerd


    To identify the power and flux density of concentrated solar radiation the Institute of Solar Research at the German Aerospace Center (DLR - Deutsches Zentrum für Luft-und Raumfahrt e. V.) has used the camera-based measurement system FATMES (Flux and Temperature Measurement System) since 1995. The disadvantages of low resolution, difficult handling and poor computing power required a revision of the existing measurement system. The measurement system FMAS (Flux Mapping Acquisition system) is equipped with state-of-the-art-hardware, is compatible with computers off-the-shelf and is programmed in LabView. The expenditure of time for an image evaluation is reduced by the factor 60 compared to FATMES. The new measurement system is no longer associated with the facilities Solar Furnace and High Flux Solar Simulator at the DLR in Cologne but is also applicable as a mobile system. The data and the algorithms are transparent throughout the complete process. The measurement accuracy of FMAS is determined to at most ±3 % until now. The error of measurement of FATMES is at least 2 % higher according to the conducted comparison tests.

  14. Rapid and economical data acquisition in ultrafast frequency-resolved spectroscopy using choppers and a microcontroller. (United States)

    Guo, Liang; Monahan, Daniele M; Fleming, Graham


    Spectrometers and cameras are used in ultrafast spectroscopy to achieve high resolution in both time and frequency domains. Frequency-resolved signals from the camera pixels cannot be processed by common lock-in amplifiers, which have only a limited number of input channels. Here we demonstrate a rapid and economical method that achieves the function of a lock-in amplifier using mechanical choppers and a programmable microcontroller. We demonstrate the method's effectiveness by performing a frequency-resolved pump-probe measurement on the dye Nile Blue in solution.

  15. Magnetization-prepared shells trajectory with automated gradient waveform design. (United States)

    Shu, Yunhong; Tao, Shengzhen; Trzasko, Joshua D; Huston, John; Weavers, Paul T; Bernstein, Matt A


    To develop a fully automated trajectory and gradient waveform design for the non-Cartesian shells acquisition, and to develop a magnetization-prepared (MP) shells acquisition to achieve an efficient three-dimensional acquisition with improved gray-to-white brain matter contrast. After reviewing the shells k-space trajectory, a novel, fully automated trajectory design is developed that allows for gradient waveforms to be automatically generated for specified acquisition parameters. Designs for two types of shells are introduced, including fully sampled and undersampled/accelerated shells. Using those designs, an MP-Shells acquisition is developed by adjusting the acquisition order of shells interleaves to synchronize the center of k-space sampling with the peak of desired gray-to-white matter contrast. The feasibility of the proposed design and MP-Shells is demonstrated using simulation, phantom, and volunteer subject experiments, and the performance of MP-Shells is compared with a clinical Cartesian magnetization-prepared rapid gradient echo acquisition. Initial experiments show that MP-Shells produces excellent image quality with higher data acquisition efficiency and improved gray-to-white matter contrast-to-noise ratio (by 36%) compared with the conventional Cartesian magnetization-prepared rapid gradient echo acquisition. We demonstrated the feasibility of a three-dimensional MP-Shells acquisition and an automated trajectory design to achieve an efficient acquisition with improved gray-to-white matter contrast. Magn Reson Med, 2017. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  16. Rapid acquisition strategy for functional T1ρ mapping of the brain. (United States)

    Johnson, Casey P; Heo, Hye-Young; Thedens, Daniel R; Wemmie, John A; Magnotta, Vincent A


    Functional T1ρ mapping has been proposed as a method to assess pH and metabolism dynamics in the brain with high spatial and temporal resolution. The purpose of this work is to describe and evaluate a variant of the spin-locked echo-planar imaging sequence for functional T1ρ mapping at 3T. The proposed sequence rapidly acquires a time series of T1ρ maps with 4.0second temporal resolution and 10 slices of volumetric coverage. Simulation, phantom, and in vivo experiments are used to evaluate many aspects of the sequence and its implementation including fidelity of measured T1ρ dynamics, potential confounds to the T1ρ response, imaging parameter tradeoffs, time series analysis approaches, and differences compared to blood oxygen level dependent functional magnetic resonance imaging. It is shown that the high temporal resolution and volumetric coverage of the sequence are obtained with some expense including underestimation of the T1ρ response, sensitivity to T1 dynamics, and reduced signal-to-noise ratio. In vivo studies using a flashing checkerboard functional magnetic resonance imaging paradigm suggest differences between T1ρ and blood oxygen level dependent activation patterns. Possible sources of the functional T1ρ response and potential sequence improvements are discussed. The capability of T1ρ to map whole-brain pH and metabolism dynamics with high temporal and spatial resolution is potentially unique and warrants further investigation and development. Copyright © 2014 Elsevier Inc. All rights reserved.

  17. Evaluation of a multiple spin- and gradient-echo (SAGE) EPI acquisition with SENSE acceleration: applications for perfusion imaging in and outside the brain. (United States)

    Skinner, Jack T; Robison, Ryan K; Elder, Christopher P; Newton, Allen T; Damon, Bruce M; Quarles, C Chad


    Perfusion-based changes in MR signal intensity can occur in response to the introduction of exogenous contrast agents and endogenous tissue properties (e.g. blood oxygenation). MR measurements aimed at capturing these changes often implement single-shot echo planar imaging (ssEPI). In recent years ssEPI readouts have been combined with parallel imaging (PI) to allow fast dynamic multi-slice imaging as well as the incorporation of multiple echoes. A multiple spin- and gradient-echo (SAGE) EPI acquisition has recently been developed to allow measurement of transverse relaxation rate (R2 and R2(*)) changes in dynamic susceptibility contrast (DSC)-MRI experiments in the brain. With SAGE EPI, the use of PI can influence image quality, temporal resolution, and achievable echo times. The effect of PI on dynamic SAGE measurements, however, has not been evaluated. In this work, a SAGE EPI acquisition utilizing SENSE PI and partial Fourier (PF) acceleration was developed and evaluated. Voxel-wise measures of R2 and R2(*) in healthy brain were compared using SAGE EPI and conventional non-EPI multiple echo acquisitions with varying SENSE and PF acceleration. A conservative SENSE factor of 2 with PF factor of 0.73 was found to provide accurate measures of R2 and R2(*) in white (WM) (rR2=[0.55-0.79], rR2*=[0.47-0.71]) and gray (GM) matter (rR2=[0.26-0.59], rR2*=[0.39-0.74]) across subjects. The combined use of SENSE and PF allowed the first dynamic SAGE EPI measurements in muscle, with a SENSE factor of 3 and PF factor of 0.6 providing reliable relaxation rate estimates when compared to multi-echo methods. Application of the optimized SAGE protocol in DSC-MRI of high-grade glioma patients provided T1 leakage-corrected estimates of CBV and CBF as well as mean vessel diameter (mVD) and simultaneous measures of DCE-MRI parameters K(trans) and ve. Likewise, application of SAGE in a muscle reperfusion model allowed dynamic measures of R2', a parameter that has been shown to correlate

  18. Cartilage imaging at 3.0T with gradient refocused acquisition in the steady-state (GRASS) and IDEAL fat-water separation. (United States)

    Kijowski, Richard; Tuite, Michael; Passov, Leo; Shimakawa, Ann; Yu, Huanzhou; Hu, Huanzhou; Reeder, Scott B


    To demonstrate the feasibility of evaluating the articular cartilage of the knee joint at 3.0T using gradient refocused acquisition in the steady-state (GRASS) and iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) fat-water separation. Bloch equation simulations and a clinical pilot study (n = 10 knees) were performed to determine the influence of flip angle of the IDEAL-GRASS sequence on the signal-to-noise ratio (SNR) of cartilage and synovial fluid and the contrast-to-noise ratio (CNR) between cartilage and synovial fluid at 3.0T. The optimized IDEAL-GRASS sequence was then performed on 30 symptomatic patients as part of the routine 3.0T knee MRI examination at our institution. The optimal flip angle was 50 degrees for IDEAL-GRASS cartilage imaging, which maximized contrast between cartilage and synovial fluid. The IDEAL-GRASS sequence consistently produced high-quality fat- and water-separated images of the knee with bright synovial fluid and 0.39 x 0.67 x 1.0 mm resolution in 5 minutes. IDEAL-GRASS images had high cartilage SNR and high contrast between cartilage and adjacent joint structures. The IDEAL-GRASS sequence provided excellent visualization of cartilage lesions in all patients. The IDEAL-GRASS sequence shows promise for use as a morphologic cartilage imaging sequence at 3.0T. (c) 2008 Wiley-Liss, Inc.

  19. Rapid Automatic Lighting Control of a Mixed Light Source for Image Acquisition using Derivative Optimum Search Methods

    Directory of Open Access Journals (Sweden)

    Kim HyungTae


    Full Text Available Automatic lighting (auto-lighting is a function that maximizes the image quality of a vision inspection system by adjusting the light intensity and color.In most inspection systems, a single color light source is used, and an equal step search is employed to determine the maximum image quality. However, when a mixed light source is used, the number of iterations becomes large, and therefore, a rapid search method must be applied to reduce their number. Derivative optimum search methods follow the tangential direction of a function and are usually faster than other methods. In this study, multi-dimensional forms of derivative optimum search methods are applied to obtain the maximum image quality considering a mixed-light source. The auto-lighting algorithms were derived from the steepest descent and conjugate gradient methods, which have N-size inputs of driving voltage and one output of image quality. Experiments in which the proposed algorithm was applied to semiconductor patterns showed that a reduced number of iterations is required to determine the locally maximized image quality.

  20. A rapid fabrication of C/C composites by a thermal gradient chemical vapor infiltration method with vaporized kerosene as a precursor

    Energy Technology Data Exchange (ETDEWEB)

    Wang Jiping [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)]. E-mail:; Qian Junmin [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Qiao Guanjun [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Jin Zhihao [State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China)


    A thermal gradient, atmospheric pressure chemical vapor infiltration method with simultaneous vaporized kerosene as a precursor for rapid fabrication of C/C composites was studied. By this method, carbon felts (bulk density {approx}0.2 g cm{sup -3}) were densified to C/C composites with density of 1.67 and 1.71 g cm{sup -3} when prepared at 1050 and 1150 deg. C for 6 h, respectively. X-ray diffraction result indicates that the composites have a strong ability to graphitize and the higher deposition temperature leads to the increased graphitization degree. Polarized light microscope and scanning electron microscope images reveal that fibers of the composites prepared for 6 h are surrounded by ring-shaped pyrocarbon matrix with a thickness of {approx}20 {mu}m, and that the matrix is delaminated to 4-6 layer-like regions. The deposition process is analyzed by dividing the reactor into four regions associated with specific functions and the reasons for the rapid fabrication are proposed as the short convection and diffusion path for the precursor and the existing of thermal gradient across the preform.

  1. Analysis of Gradient Waveform in Magnetic Resonance Imaging

    Directory of Open Access Journals (Sweden)

    OU-YANG Shan-mei


    Full Text Available The accuracy of gradient pulse waveform affects image quality significantly in magnetic resonance imaging (MRI. Recording and analyzing the waveform of gradient pulse helps to make rapid and accurate diagnosis of spectrometer gradient hardware and/or pulse sequence. Using the virtual instrument software LabVIEW to control the high speed data acquisition card DAQ-2005, a multi-channel acquisition scheme was designed to collect the gradient outputs from a custom-made spectrometer. The collected waveforms were post-processed (i.e., histogram statistical analysis, data filtering and difference calculation to obtain feature points containing time and amplitude information. Experiments were carried out to validate the method, which is an auxiliary test method for the development of spectrometer and pulses sequence.

  2. Inducing magnetic anisotropy and optimized microstructure in rapidly solidified Nd-Fe-B based magnets by thermal gradient, magnetic field and hot deformation (United States)

    Zhao, L. Z.; Li, W.; Wu, X. H.; Hussain, M.; Liu, Z. W.; Zhang, G. Q.; Greneche, J. M.


    Direct preparation of Nd-Fe-B alloys by rapid solidification of copper mold casting is a very simple and low cost process for mini-magnets, but these magnets are generally magnetically isotropic. In this work, high coercivity Nd24Co20Fe41B11Al4 rods were produced by injection casting. To induce magnetic anisotropy, temperature gradient, assisted magnetic field, and hot deformation (HD) procedures were employed. As-cast samples showed non-uniform microstructure due to the melt convection. The thermal gradient during solidification led to the formation of radially distributed acicular hard magnetic grains, which gives the magnetic anisotropy. The growth of the oriented grains was confirmed by phase field simulation. A magnetic field up to 1 T applied along the casting direction could not induce significant magnetic anisotropy, but it improved the magnetic properties by reducing the non-uniformity and forming a uniform microstructure. The annealed alloys exhibited high intrinsic coercivity but disappeared anisotropy. HD was demonstrated to be a good approach for inducing magnetic anisotropy and enhanced coercivity by deforming and refining the grains. This work provides an alternative approach for preparing fully dense Nd-rich anisotropic bulk Nd-Fe-B magnets.

  3. Application of stepwise gradients in counter-current chromatography: a rapid and economical strategy for the one-step separation of eight coumarins from Seseli resinosum. (United States)

    Shehzad, Omer; Khan, Salman; Ha, In Jin; Park, Youmie; Tosun, Alev; Kim, Yeong Shik


    The targeted purification of compounds with a broad polarity range from traditional medicinal plants is a big challenge for counter-current chromatography (CCC). Gradient elution was introduced in CCC to address this problem. However, once a suitable solvent system is selected, the separation process requires optimization of operational parameters. The present study was conducted to optimize various operational parameters to integrate the flow rate and solvent gradients for the rapid isolation of eight coumarins from Seseli resinosum in a single run. An increase in the system temperature from 15°C to 35°C increased the stationary phase retention and solubility of the sample, whereas the operation time and viscosity of the system were decreased. The high purity of each compound was ensured by collecting the fractions from the main peaks while all the shoulder peaks were mixed and separated under the same conditions with semi-preparative CCC. GC-FID was used to analyze the components of each phase, which was prepared without presaturation to save the time and solvent consumption. Finally, eight coumarins were purified, including (1) d-laserpitin, (2) (3'S,4'S)-3'-angeloyloxy-4'-hydroxy-3',4'-dihydroseselin, (3) (+)-samidin, (4) (3'S,4'S)-3'-acetoxy-4'-angeloyloxy-3',4'-dihydroseselin, (5) deltoin (6), calipteryxin, (7) (3'S,4'S)-3',4'-disenecioyloxy-3',4'-dihydroseselin, and (8) (-)-anomalin. The present technique has successfully accomplished the goal of one-step separation of these compounds with high purity and recovery in an economic and time efficient manner. Copyright © 2013 Elsevier B.V. All rights reserved.

  4. First results in rapid MR imaging of focal liver and spleen lesions using field echos and small angle excitation (gradient echo sequences)

    Energy Technology Data Exchange (ETDEWEB)

    Griebel, J.; Hess, C.F.; Kurtz, B.; Klose, U.; Kueper, K.


    15 healthy subjects and 39 patients with focal liver and spleen lesions were examined via MR tomography at 1.5 tesla. Gradient field echos at small angle excitation (< 90/sup 0/) were employed. The imaging time per layer was 10 seconds so that rapid imaging could be carried out at respiratory standstill. This enabled visualisation of liver and spleen without interference by breathing artifacts and with accurate localisation. Focal lesions can be imaged best at low flip-angle pulses (liver) or low to medium-angle pulses (spleen). The primary liver cell carcinoma is visualised as an inhomogeneous structure with similar signal intensity as the surrounding tissue. All other examined liver lesions (metastases, haemangiomas, lymphatic infiltrates, echinococcus cysts, FNH, gummae) showed greater signal intensity than the remaining organ at small angle excitation. Furthermore, contrast reversals were seen at medium-angle pulses. Contrariwise, with the exception of the light-coloured spleen infarcts, spleen lesions (lymphatic infiltrate, Boeck's disease or sarcoidosis) appeared darker at all excitation angles than the surrounding tissue.

  5. Rapid profiling of polymeric phenolic acids in Salvia miltiorrhiza by hybrid data-dependent/targeted multistage mass spectrometry acquisition based on expected compounds prediction and fragment ion searching. (United States)

    Shen, Yao; Feng, Zijin; Yang, Min; Zhou, Zhe; Han, Sumei; Hou, Jinjun; Li, Zhenwei; Wu, Wanying; Guo, De-An


    Phenolic acids are the major water-soluble components in Salvia miltiorrhiza (> 5%). According to previous studies, many of them contribute to the cardiovascular effects and antioxidant effects of S. miltiorrhiza. Polymeric phenolic acids can be considered as the tanshinol derived metabolites, e.g., dimmers, trimers and tetramers. A strategy combined with tanshinol-based expected compounds prediction, total ion chromatogram filtering, Fragment Ion Searching and parent list-based multistage mass spectrometry acquisition by Linear Trap Quadropole-orbitrap Velos Mass Spectrometry was proposed to rapid profile polymeric phenolic acids in S. miltiorrhiza. More than 480 potential polymeric phenolic acids could be screened out by this strategy. Based on the fragment information obtained by parent list-activated data dependent multistage mass spectrometry acquisition, 190 polymeric phenolic acids were characterized by comparing their mass information with literature data, and 18 of them were firstly detected from S. miltiorrhiza. Seven potential compounds were tentatively characterized as new polymeric phenolic acids from S. miltiorrhiza. This strategy facilitates identification of polymeric phenolic acids in complex matrix with both selectivity and sensitivity, which could be expanded for rapid discovery and identification of compounds from complex matrix. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  6. Rapid high-resolution three-dimensional mapping of T1 and age-dependent variations in the non-human primate brain using magnetization-prepared rapid gradient-echo (MPRAGE) sequence (United States)

    Liu, Junjie V.; Bock, Nicholas A.; Silva, Afonso C.


    The use of quantitative T1 mapping in neuroscience and neurology has raised strong interest in the development of T1-mapping techniques that can measure T1 in the whole brain, with high accuracy and precision and within short imaging and computation times. Here, we present a new inversion-recovery (IR) based T1-mapping method using a standard 3D magnetization-prepared rapid gradient-echo (MPRAGE) sequence. By varying only the inversion time (TI), but keeping other parameters constant, MPRAGE image signals become linear to exp(−TI/T1), allowing for accurate T1 estimation without flip angle correction. We also show that acquiring data at just 3 TIs, with the three different TI values optimized, gives maximum T1 precision per unit time, allowing for new efficient approaches to measure and compute T1. We demonstrate the use of our method at 7 Tesla to obtain 3D T1 maps of the whole brain in common marmosets at 0.60 mm resolution and within 11 minutes. T1 maps from the same individuals were highly reproducible across different days. Across subjects, the peak of cerebral gray matter T1 distribution was 1735±52 ms, and the lower edge of cerebral white matter T1 distribution was 1270±43 ms. We found a significant decrease of T1 in both gray and white matter of the marmoset brain with age over a span of 14 years, in agreement with previous human studies. This application illustrates that MPRAGE-based 3D T1 mapping is rapid, accurate and precise, and can facilitate high-resolution anatomical studies in neuroscience and neurological diseases. PMID:21376814

  7. Prospector: A web-based tool for rapid acquisition of gold standard data for pathology research and image analysis

    Directory of Open Access Journals (Sweden)

    Alexander I Wright


    Full Text Available Background: Obtaining ground truth for pathological images is essential for various experiments, especially for training and testing image analysis algorithms. However, obtaining pathologist input is often difficult, time consuming and expensive. This leads to algorithms being over-fitted to small datasets, and inappropriate validation, which causes poor performance on real world data. There is a great need to gather data from pathologists in a simple and efficient manner, in order to maximise the amount of data obtained. Methods: We present a lightweight, web-based HTML5 system for administering and participating in data collection experiments. The system is designed for rapid input with minimal effort, and can be accessed from anywhere in the world with a reliable internet connection. Results: We present two case studies that use the system to assess how limitations on fields of view affect pathologist agreement, and to what extent poorly stained slides affect judgement. In both cases, the system collects pathologist scores at a rate of less than two seconds per image. Conclusions: The system has multiple potential applications in pathology and other domains.

  8. Générateur de timing local pour l'acquisition des transformateurs rapides (LEIR, LINAC 3, LINAC 2, Ligne d'injection PSB)

    CERN Document Server

    Schnell, J D


    Dans le cadre des acquisitions des transformateurs rapides des deux LINACS, de la ligne d'injection PSB et de la machine LEIR, un nouveau hardware a été mis en opération [1]. Celui-ci assure la digitalisation des signaux analogiques et aussi de certains signaux de timing devant cadrer la mesure. Pour ce faire des ADC SIS3300 (SIS3320) et des DPRAM 80408 sont mis en service. Ces unités nécéssitent pour leur fonctionnement des horloges et des timings qui normalement sont intégralement fournis par l'équipement standard CO, notamment des CTRV et autres TG8. Suite à des problèmes d'approvisionnement, il existe des cas où l'on ne dispose pas (du moins pour le court terme) de suffisemment de ressources standard pour pourvoir au timing mentionné plus haut. Le tiroir qui fait l'objet de la présente description assure, avec certaines limitations, la génération des timings et autres horloges utilisées par les DPRAM 80408 et les ADC SIS3300.

  9. Rapid acquisition of helium-3 and proton three-dimensional image sets of the human lung in a single breath-hold using compressed sensing. (United States)

    Qing, Kun; Altes, Talissa A; Tustison, Nicholas J; Feng, Xue; Chen, Xiao; Mata, Jaime F; Miller, G Wilson; de Lange, Eduard E; Tobias, William A; Cates, Gordon D; Brookeman, James R; Mugler, John P


    To develop and validate a method for acquiring helium-3 ((3) He) and proton ((1) H) three-dimensional (3D) image sets of the human lung with isotropic spatial resolution within a 10-s breath-hold by using compressed sensing (CS) acceleration, and to assess the fidelity of undersampled images compared with fully sampled images. The undersampling scheme for CS acceleration was optimized and tested using (3) He ventilation data. Rapid 3D acquisition of both (3) He and (1) H data during one breath-hold was then implemented, based on a balanced steady-state free-precession pulse sequence, by random undersampling of k-space with reconstruction by means of minimizing the L1 norm and total variance. CS-reconstruction fidelity was evaluated quantitatively by comparing fully sampled and retrospectively undersampled image sets. Helium-3 and (1) H 3D image sets of the lung with isotropic 3.9-mm resolution were acquired during a single breath-hold in 12 s and 8 s using acceleration factors of 2 and 3, respectively. Comparison of fully sampled and retrospectively undersampled (3) He and (1) H images yielded mean absolute errors 0.9. By randomly undersampling k-space and using CS reconstruction, high-quality (3) He and (1) H 3D image sets with isotropic 3.9-mm resolution can be acquired within an 8-s breath-hold. © 2014 Wiley Periodicals, Inc.

  10. A single-shot T2mapping protocol based on echo-split gradient-spin-echo acquisition and parametric multiplexed sensitivity encoding based on projection onto convex sets reconstruction. (United States)

    Chu, Mei-Lan; Chang, Hing-Chiu; Oshio, Koichi; Chen, Nan-Kuei


    To develop a high-speed T 2 mapping protocol that is capable of accurately measuring T 2 relaxation time constants from a single-shot acquisition. A new echo-split single-shot gradient-spin-echo (GRASE) pulse sequence is developed to acquire multicontrast data while suppressing signals from most nonprimary echo pathways in Carr-Purcell-Meiboom-Gill (CPMG) echoes. Residual nonprimary pathway signals are taken into consideration when performing T 2 mapping using a parametric multiplexed sensitivity encoding based on projection onto convex sets (parametric-POCSMUSE) reconstruction method that incorporates extended phase graph modeling of GRASE signals. The single-shot echo-split GRASE-based T 2 mapping procedure was evaluated in human studies at 3 Tesla. The acquired data were compared with reference data obtained with a more time-consuming interleaved spin-echo echo planar imaging protocol. T 2 maps derived from conventional single-shot GRASE scans, in which nonprimary echo pathways were not appropriately addressed, were also evaluated. Using the developed single-shot T 2 mapping protocol, quantitatively accurate T 2 maps can be obtained with a short scan time (parametric-POCSMUSE reconstruction. Magn Reson Med 79:383-393, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  11. A low-cost multielectrode system for data acquisition enabling real-time closed-loop processing with rapid recovery from stimulation artifacts

    Directory of Open Access Journals (Sweden)

    John D Rolston


    Full Text Available Commercially available data acquisition systems for multielectrode recording from freely moving animals are expensive, often rely on proprietary software, and do not provide detailed, modifiable circuit schematics. When used in conjunction with electrical stimulation, they are prone to prolonged, saturating stimulation artifacts that prevent the recording of short-latency evoked responses. Yet electrical stimulation is integral to many experimental designs, and critical for emerging brain-computer interfacing and neuroprosthetic applications. To address these issues, we developed an easy-to-use, modifiable, and inexpensive system for multielectrode neural recording and stimulation. Setup costs are less than US$10,000 for 64 channels, an order of magnitude lower than comparable commercial systems. Unlike commercial equipment, the system recovers rapidly from stimulation and allows short-latency action potentials (<1 ms post-stimulus to be detected, facilitating closed-loop applications and exposing neural activity that would otherwise remain hidden. To illustrate this capability, evoked activity from microstimulation of the rodent hippocampus is presented. The system is modular, in banks of 16 channels, and flexible in usage: while primarily designed for in vivo use, it can be combined with commercial preamplifiers to record from in vitro multielectrode arrays. The system’s open-source control software, NeuroRighter, is implemented in C#, with an easy-to-use graphical interface. As C# functions in a managed code environment, which may impact performance, analysis was conducted to ensure comparable speed to C++ for this application. Hardware schematics, layout files, and software are freely available. Since maintaining wired headstage connections with freely moving animals is difficult, we describe a new method of electrode-headstage coupling using neodymium magnets.

  12. Thermal Gradient Data Acquisition System Documentation

    National Research Council Canada - National Science Library

    Walker, Larry D; Robinson, Scott B; Leon, Lisa


    ... that can be recorded in mice. Since acceptable commercial systems are not available, this system was custom-built to acquire data using National Instruments' versatile hardware components and LabVIEW...

  13. Dung beetle community and functions along a habitat-disturbance gradient in the Amazon: a rapid assessment of ecological functions associated to biodiversity.

    Directory of Open Access Journals (Sweden)

    Rodrigo F Braga

    Full Text Available Although there is increasing interest in the effects of habitat disturbance on community attributes and the potential consequences for ecosystem functioning, objective approaches linking biodiversity loss to functional loss are uncommon. The objectives of this study were to implement simultaneous assessment of community attributes (richness, abundance and biomass, each calculated for total-beetle assemblages as well as small- and large-beetle assemblages and three ecological functions of dung beetles (dung removal, soil perturbation and secondary seed dispersal, to compare the effects of habitat disturbance on both sets of response variables, and their relations. We studied dung beetle community attributes and functions in five land-use systems representing a disturbance gradient in the Brazilian Amazon: primary forest, secondary forest, agroforestry, agriculture and pasture. All response variables were affected negatively by the intensification of habitat disturbance regimes, but community attributes and ecological functions did not follow the same pattern of decline. A hierarchical partitioning analysis showed that, although all community attributes had a significant effect on the three ecological functions (except the abundance of small beetles on all three ecological functions and the biomass of small beetles on secondary dispersal of large seed mimics, species richness and abundance of large beetles were the community attributes with the highest explanatory value. Our results show the importance of measuring ecological function empirically instead of deducing it from community metrics.

  14. Dung beetle community and functions along a habitat-disturbance gradient in the Amazon: a rapid assessment of ecological functions associated to biodiversity. (United States)

    Braga, Rodrigo F; Korasaki, Vanesca; Andresen, Ellen; Louzada, Julio


    Although there is increasing interest in the effects of habitat disturbance on community attributes and the potential consequences for ecosystem functioning, objective approaches linking biodiversity loss to functional loss are uncommon. The objectives of this study were to implement simultaneous assessment of community attributes (richness, abundance and biomass, each calculated for total-beetle assemblages as well as small- and large-beetle assemblages) and three ecological functions of dung beetles (dung removal, soil perturbation and secondary seed dispersal), to compare the effects of habitat disturbance on both sets of response variables, and their relations. We studied dung beetle community attributes and functions in five land-use systems representing a disturbance gradient in the Brazilian Amazon: primary forest, secondary forest, agroforestry, agriculture and pasture. All response variables were affected negatively by the intensification of habitat disturbance regimes, but community attributes and ecological functions did not follow the same pattern of decline. A hierarchical partitioning analysis showed that, although all community attributes had a significant effect on the three ecological functions (except the abundance of small beetles on all three ecological functions and the biomass of small beetles on secondary dispersal of large seed mimics), species richness and abundance of large beetles were the community attributes with the highest explanatory value. Our results show the importance of measuring ecological function empirically instead of deducing it from community metrics.

  15. The Agile Rapid Global Combat Support (ARGCS) System: A Cost and Benefit Analysis of Including the ARGCS Technologies in the Acquisition of the Enhanced Consolidated Support System (ECASS) (United States)


    Franck and Carmelita Troy in January 2007. Revised in May of 2007, this interim BCA, based on the data then available, offered an assessment of Franck, Raymond and Carmelita Troy, Agile Rapid Global Combat Support, Business Case Analysis, Version 1.0. Naval

  16. Rapid acquisition and modulation of colistin-resistance by an extensively drug-resistant Acinetobacter baumannii: case report and review of current literature

    Directory of Open Access Journals (Sweden)

    Jari Intra


    Full Text Available Acinetobacter baumannii has emerged as a major cause of healthcare-associated infections. It commonly expresses clinical resistance to multiple antimicrobial agents, and hence, it is considered the paradigm of an extensively drug-resistant (XDR bacterium. XDR A. baumannii is a rapidly emerging pathogen, especially in the intensive care unit (ICU, causing nosocomial infections including sepsis, ventilatorassociated pneumonia, meningitis, peritonitis, urinary tract infection, and central venous catheter-related infection. In the present report, we described an in vivo evolution of A. baumannii strain from a colistinsusceptibility to a colistin-resistance state. A 65-year-old male, who suffered a duodenal ulcer, two days after hospitalization and during the stay in ICU, contracted a pneumonia and peritoneal infection by a carbapenem-resistant A. baumannii strain. After a combination treatment with colistin, vancomycin plus imipenem, and within seven days, the pathogen rapidly evolved in seven days to a pandrug-resistant phenotype. As the antimicrobial treatment was stopped, the A. baumannii isolate changed another time its profile to colistin, becoming newly susceptible, showing a very high level of adaptability to external conditions. We also have reviewed here the current literature on this worryingly public health threat.

  17. Mergers & Acquisitions

    DEFF Research Database (Denmark)

    Fomcenco, Alex

    MERGERS & ACQUISITIONS: Counseling and Choice of Method describes and analyzes the current state of law in Europe in regard to some relevant selected elements related to mergers and acquisitions, and the adviser’s counsel in this regard. The focus is aimed and maintained at application...

  18. The Educational Gradient in Health in China (United States)

    Chen, Qiulin; Eggleston, Karen; Zhang, Wei; Zhao, Jiaying; Zhou, Sen


    It has been well established that better educated individuals enjoy better health and longevity. In theory, the educational gradients in health could be flattening if diminishing returns to improved average education levels and the influence of earlier population health interventions outweigh the gradient-steepening effects of new medical and health technologies. This paper documents how the gradients are evolving in China, a rapidly developing country, about which little is known on this topic. Based on recent mortality data and nationally representative health surveys, we find large and, in some cases, steepening educational gradients. We also find that the gradients vary by cohort, gender and region. Further, we find that the gradients can only partially be accounted for by economic factors. These patterns highlight the double disadvantage of those with low education, and suggest the importance of policy interventions that foster both aspects of human capital for them. PMID:29056815


    National Research Council Canada - National Science Library

    Rodgers Mavhiki


      Mergers and acquisitions (M&A) tend to be dominated by M&A specialists such as lawyers, valuations specialists and investment gurus, leaving the funding function for the Chief Financial Officer (CFO...

  20. Quasi-simultaneous acquisition of hard electron ionization and soft single-photon ionization mass spectra during GC/MS analysis by rapid switching between both ionization methods: analytical concept, setup, and application on diesel fuel. (United States)

    Eschner, Markus S; Gröger, Thomas M; Horvath, Thomas; Gonin, Marc; Zimmermann, Ralf


    This work describes the realization of rapid switching between hard electron ionization (EI) and soft single-photon ionization (SPI) integrated in a compact orthogonal acceleration time-of-flight mass spectrometer. Vacuum-ultraviolet (VUV) photons of 9.8 eV (126 nm) emitted from the innovative electron-beam-pumped rare-gas excimer light source (EBEL) filled with argon are focused into the ion chamber by an ellipsoidal mirror optic for accomplishing of SPI. This novel orthogonal acceleration time-of-flight mass spectrometer with switching capability was hyphenated to one-dimensional gas chromatography (GC) and comprehensive two-dimensional (2D) gas chromatography (GC × GC) for the first time. Within this demonstration study, a maximum switching frequency of 80 Hz was applied for investigation of a mineral-oil-type diesel sample. This approach allows the quasi-simultaneous acquisition of complementary information about the fragmentation pattern (EI) as well as the molecular mass (SPI) of compounds within a single analysis. Furthermore, by application of a polar GC column for separation, the SPI data can be displayed in a 2D contour plot, leading to a comprehensive 2D characterization (GC × MS), whereas the typical group-type assignment for diesel is also met.

  1. Assessment of Accelerated Acquisition of Defense Programs (United States)


    117A Stealth Attack Aircraft Crash /rapid/time constrained/spiral Mine-Resistant/Ambush-Protected Vehicle (MRAP) Rapid/time constrained Stryker...contractor. The Air Force delivered the aircraft directly from the factory to the front lines with no developmental or operational testing . Prior...availability: 1. Time-constrained acquisition 2. “ Crash ” program 3. Rapid acquisition 4. Early fielding experiments 5. Spiral/evolutionary

  2. Tailoring Systems Engineering for Rapid Acquisition (United States)


    constraints associated with the research program, the total number interviews conducted was capped at twelve to allow proper time to conduct data analysis...incremental process or a single time solution? Incremental solutions with interviewee’s organization working the systems from cradle to grave. They are

  3. An Analysis of Army Rapid Acquisition (United States)


    IOT &E initial operational test & evaluation IT information technology IPT integrated process team IUID item unique identification IWN immediate...Forces’ efforts to defeat Improvised Explosive Devices as weapons of strategic influence.”36 JIDA focuses on defeating IEDs, attacking the network , and...deference to private industry to a frame-of-mind more appropriate for a government customer accountable to the U.S. taxpayer. The challenge here is

  4. Mergers + acquisitions. (United States)

    Hoppszallern, Suzanna


    The hospital sector in 2001 led the health care field in mergers and acquisitions. Most deals involved a network augmenting its presence within a specific region or in a market adjacent to its primary service area. Analysts expect M&A activity to increase in 2002.

  5. Mergers & Acquisitions

    DEFF Research Database (Denmark)

    Fomcenco, Alex

    This dissertation is a legal dogmatic thesis, the goal of which is to describe and analyze the current state of law in Europe in regard to some relevant selected elements related to mergers and acquisitions, and the adviser’s counsel in this regard. Having regard to the topic of the dissertation...

  6. Universal gradient descent


    Gasnikov, Alexander


    In this small book we collect many different and useful facts around gradient descent method. First of all we consider gradient descent with inexact oracle. We build a general model of optimized function that include composite optimization approach, level's methods, proximal methods etc. Then we investigate primal-dual properties of the gradient descent in general model set-up. At the end we generalize method to universal one.

  7. Gradient and vorticity banding

    NARCIS (Netherlands)

    Dhont, Jan K.G.; Briels, Willem J.


    "Banded structures" of macroscopic dimensions can be induced by simple shear flow in many different types of soft matter systems. Depending on whether these bands extend along the gradient or vorticity direction, the banding transition is referred to as "gradient banding" or "vorticity banding,"

  8. Conjugate Gradient Algorithms For Manipulator Simulation (United States)

    Fijany, Amir; Scheid, Robert E.


    Report discusses applicability of conjugate-gradient algorithms to computation of forward dynamics of robotic manipulators. Rapid computation of forward dynamics essential to teleoperation and other advanced robotic applications. Part of continuing effort to find algorithms meeting requirements for increased computational efficiency and speed. Method used for iterative solution of systems of linear equations.

  9. Second gradient poromechanics

    CERN Document Server

    Sciarra, Giulio; Coussy, Olivier


    Second gradient theories have been developed in mechanics for treating different phenomena as capillarity in fluids, plasticity and friction in granular materials or shear band deformations. Here, there is an attempt of formulating a second gradient Biot like model for porous materials. In particular the interest is focused in describing the local dilatant behaviour of a porous material induced by pore opening elastic and capillary interaction phenomena among neighbouring pores and related micro-filtration phenomena by means of a continuum microstructured model. The main idea is to extend the classical macroscopic Biot model by including in the description second gradient effects. This is done by assuming that the surface contribution to the external work rate functional depends on the normal derivative of the velocity or equivalently assuming that the strain work rate functional depends on the porosity and strain gradients. According to classical thermodynamics suitable restrictions for stresses and second g...

  10. 2017 NAIP Acquisition Map (United States)

    Farm Service Agency, Department of Agriculture — Planned States for 2017 NAIP acquisition and acquisition status layer (updated daily). Updates to the acquisition seasons may be made during the season to...

  11. Compensation of Slice Profile Mismatch in Combined Spin- And Gradient-Echo EPI Pulse Sequences


    Schmiedeskamp, Heiko; Straka, Matus; Bammer, Roland


    Combined acquisition of gradient-echo and spin-echo signals in MRI time series reveals additional information for perfusion-weighted imaging and functional magnetic resonance imaging due to differences in the sensitivity of gradient-echo and spin-echo measurements to the properties of the underlying vascular architecture. The acquisition of multiple echo trains within one time frame facilitates the simultaneous estimation of the transversal relaxation parameters R2 and R2*. However, the simul...

  12. High Gradient Accelerator Research

    Energy Technology Data Exchange (ETDEWEB)

    Temkin, Richard [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Dept. of Physics. Plasma Science and Fusion Center


    The goal of the MIT program of research on high gradient acceleration is the development of advanced acceleration concepts that lead to a practical and affordable next generation linear collider at the TeV energy level. Other applications, which are more near-term, include accelerators for materials processing; medicine; defense; mining; security; and inspection. The specific goals of the MIT program are: • Pioneering theoretical research on advanced structures for high gradient acceleration, including photonic structures and metamaterial structures; evaluation of the wakefields in these advanced structures • Experimental research to demonstrate the properties of advanced structures both in low-power microwave cold test and high-power, high-gradient test at megawatt power levels • Experimental research on microwave breakdown at high gradient including studies of breakdown phenomena induced by RF electric fields and RF magnetic fields; development of new diagnostics of the breakdown process • Theoretical research on the physics and engineering features of RF vacuum breakdown • Maintaining and improving the Haimson / MIT 17 GHz accelerator, the highest frequency operational accelerator in the world, a unique facility for accelerator research • Providing the Haimson / MIT 17 GHz accelerator facility as a facility for outside users • Active participation in the US DOE program of High Gradient Collaboration, including joint work with SLAC and with Los Alamos National Laboratory; participation of MIT students in research at the national laboratories • Training the next generation of Ph. D. students in the field of accelerator physics.

  13. Preconditioned Stochastic Gradient Descent. (United States)

    Li, Xi-Lin


    Stochastic gradient descent (SGD) still is the workhorse for many practical problems. However, it converges slow, and can be difficult to tune. It is possible to precondition SGD to accelerate its convergence remarkably. But many attempts in this direction either aim at solving specialized problems, or result in significantly more complicated methods than SGD. This paper proposes a new method to adaptively estimate a preconditioner, such that the amplitudes of perturbations of preconditioned stochastic gradient match that of the perturbations of parameters to be optimized in a way comparable to Newton method for deterministic optimization. Unlike the preconditioners based on secant equation fitting as done in deterministic quasi-Newton methods, which assume positive definite Hessian and approximate its inverse, the new preconditioner works equally well for both convex and nonconvex optimizations with exact or noisy gradients. When stochastic gradient is used, it can naturally damp the gradient noise to stabilize SGD. Efficient preconditioner estimation methods are developed, and with reasonable simplifications, they are applicable to large-scale problems. Experimental results demonstrate that equipped with the new preconditioner, without any tuning effort, preconditioned SGD can efficiently solve many challenging problems like the training of a deep neural network or a recurrent neural network requiring extremely long-term memories.

  14. Disaster response contracting in a post-Katrina world: analyzing current disaster response strategies and exploring alternatives to improve acquisition processes for rapid reaction to large scale disasters within the United States


    King, Jerry A.; McKay, Joshua H.


    MBA Professional Report Considerable public scrutiny has been focused on the Federal Governmentb2ss, especially the Federal Emergency Management Agencyb2ss (FEMA) supposed inadequate, misdirected, and slow response to the acquisition needs required for responding to the aftermath of hurricane Katrina. This seemingly failed response quite possibly cost the Federal Government billions in wasted taxpayer dollars and has affected the livelihood of thousands. Analyzing what went wrong and exami...

  15. Uniform gradient expansions

    Directory of Open Access Journals (Sweden)

    Massimo Giovannini


    Full Text Available Cosmological singularities are often discussed by means of a gradient expansion that can also describe, during a quasi-de Sitter phase, the progressive suppression of curvature inhomogeneities. While the inflationary event horizon is being formed the two mentioned regimes coexist and a uniform expansion can be conceived and applied to the evolution of spatial gradients across the protoinflationary boundary. It is argued that conventional arguments addressing the preinflationary initial conditions are necessary but generally not sufficient to guarantee a homogeneous onset of the conventional inflationary stage.

  16. Probabilistic Multileave Gradient Descent

    NARCIS (Netherlands)

    Oosterhuis, H.; Schuth, A.; de Rijke, M.; Ferro, N.; Crestani, F.; Moens, M.-F.; Mothe, J.; Silvestri, F.; Di Nunzio, G.M.; Hauff, C.; Silvello, G.


    Online learning to rank methods aim to optimize ranking models based on user interactions. The dueling bandit gradient descent (DBGD) algorithm is able to effectively optimize linear ranking models solely from user interactions. We propose an extension of DBGD, called probabilistic multileave

  17. Speed in Acquisitions

    DEFF Research Database (Denmark)

    Meglio, Olimpia; King, David R.; Risberg, Annette


    The advantage of speed is often invoked by academics and practitioners as an essential condition during post-acquisition integration, frequently without consideration of the impact earlier decisions have on acquisition speed. In this article, we examine the role speed plays in acquisitions across...... the acquisition process using research organized around characteristics that display complexity with respect to acquisition speed. We incorporate existing research with a process perspective of acquisitions in order to present trade-offs, and consider the influence of both stakeholders and the pre......-deal-completion context on acquisition speed, as well as the organization’s capabilities to facilitating that speed. Observed trade-offs suggest both that acquisition speed often requires longer planning time before an acquisition and that associated decisions require managerial judgement. A framework for improving...

  18. Language Acquisition without an Acquisition Device (United States)

    O'Grady, William


    Most explanatory work on first and second language learning assumes the primacy of the acquisition phenomenon itself, and a good deal of work has been devoted to the search for an "acquisition device" that is specific to humans, and perhaps even to language. I will consider the possibility that this strategy is misguided and that language…

  19. Increasing SLEDed Linac Gradient

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, Zoltan D


    This note will show how to increase the SLED [1] gradient by varying Q{sub e}, the external Q of the SLED cavity, by increasing its Q{sub 0} and by increasing the compression ratio. If varying the external Q is to be effective, then the copper losses should be small so that Q{sub 0} >> Q{sub e}. Methods of varying Q{sub e} will be indicated but no experimental data will be presented. If we increase the klystron pulse width from 3.5 to 5 {micro}S and increase Q{sub 0} from the present 100000 to 300000, then the gradient increases by 19% and the beam energy increases from 50 to 60 GeV. This note will also discuss SLED operation at 11424 MHz, the NLC frequency. Without Q{sub e} switching, using SLED at 11424 MHz increases the SLAC gradient from 21 MV/m to 34 MV/m, and at the same repetition rate, uses about 1/5 of rf average power. If we also double the compression ratio, we reach 47 MV/m and over 100 GeV beam energy.

  20. Modelling live forensic acquisition

    CSIR Research Space (South Africa)

    Grobler, MM


    Full Text Available This paper discusses the development of a South African model for Live Forensic Acquisition - Liforac. The Liforac model is a comprehensive model that presents a range of aspects related to Live Forensic Acquisition. The model provides forensic...

  1. Managing acquisitions and mergers. (United States)

    Shorr, A S


    Acquisitions and mergers must be well managed if they are to capture market share and achieve profitability. Acquisition strategies must reflect sensitivity to legal, financial and community factors and to the internal strengths, needs and weaknesses of both organizations.

  2. Playing at Serial Acquisitions

    NARCIS (Netherlands)

    J.T.J. Smit (Han); T. Moraitis (Thras)


    textabstractBehavioral biases can result in suboptimal acquisition decisions-with the potential for errors exacerbated in consolidating industries, where consolidators design serial acquisition strategies and fight escalating takeover battles for platform companies that may determine their future

  3. Calo trigger acquisition system

    CERN Multimedia

    Franchini, Matteo


    Calo trigger acquisition system - Evolution of the acquisition system from a multiple boards system (upper, orange cables) to a single board one (below, light blue cables) where all the channels are collected in a single board.

  4. Acquisition: Acquisition of the Evolved SEASPARROW Missile

    National Research Council Canada - National Science Library


    .... The Evolved SEASPARROW Missile, a Navy Acquisition Category II program, is an improved version of the RIM-7P SEASPARROW missile that will intercept high-speed maneuvering, anti-ship cruise missiles...

  5. Near-surface temperature gradient in a coastal upwelling regime (United States)

    Maske, H.; Ochoa, J.; Almeda-Jauregui, C. O.; Ruiz-de la Torre, M. C.; Cruz-López, R.; Villegas-Mendoza, J. R.


    In oceanography, a near homogeneous mixed layer extending from the surface to a seasonal thermocline is a common conceptual basis in physics, chemistry, and biology. In a coastal upwelling region 3 km off the coast in the Mexican Pacific, we measured vertical density gradients with a free-rising CTD and temperature gradients with thermographs at 1, 3, and 5 m depths logging every 5 min during more than a year. No significant salinity gradient was observed down to 10 m depth, and the CTD temperature and density gradients showed no pronounced discontinuity that would suggest a near-surface mixed layer. Thermographs generally logged decreasing temperature with depth with gradients higher than 0.2 K m-1 more than half of the time in the summer between 1 and 3 m, 3 and 5 m and in the winter between 1 and 3 m. Some negative temperature gradients were present and gradients were generally highly variable in time with high peaks lasting fractions of hours to hours. These temporal changes were too rapid to be explained by local heating or cooling. The pattern of positive and negative peaks might be explained by vertical stacks of water layers of different temperatures and different horizontal drift vectors. The observed near-surface gradient has implications for turbulent wind energy transfer, vertical exchange of dissolved and particulate water constituents, the interpretation of remotely sensed SST, and horizontal wind-induced transport.

  6. Iconicity and Sign Lexical Acquisition: A Review. (United States)

    Ortega, Gerardo


    The study of iconicity, defined as the direct relationship between a linguistic form and its referent, has gained momentum in recent years across a wide range of disciplines. In the spoken modality, there is abundant evidence showing that iconicity is a key factor that facilitates language acquisition. However, when we look at sign languages, which excel in the prevalence of iconic structures, there is a more mixed picture, with some studies showing a positive effect and others showing a null or negative effect. In an attempt to reconcile the existing evidence the present review presents a critical overview of the literature on the acquisition of a sign language as first (L1) and second (L2) language and points at some factor that may be the source of disagreement. Regarding sign L1 acquisition, the contradicting findings may relate to iconicity being defined in a very broad sense when a more fine-grained operationalisation might reveal an effect in sign learning. Regarding sign L2 acquisition, evidence shows that there is a clear dissociation in the effect of iconicity in that it facilitates conceptual-semantic aspects of sign learning but hinders the acquisition of the exact phonological form of signs. It will be argued that when we consider the gradient nature of iconicity and that signs consist of a phonological form attached to a meaning we can discern how iconicity impacts sign learning in positive and negative ways.

  7. Generalized conjugate gradient squared

    Energy Technology Data Exchange (ETDEWEB)

    Fokkema, D.R.; Sleijpen, G.L.G. [Utrecht Univ. (Netherlands)


    In order to solve non-symmetric linear systems of equations, the Conjugate Gradient Squared (CGS) is a well-known and widely used iterative method. In practice the method converges fast, often twice as fast as the Bi-Conjugate Gradient method. This is what you may expect, since CGS uses the square of the BiCG polynomial. However, CGS may suffer from its erratic convergence behavior. The method may diverge or the approximate solution may be inaccurate. BiCGSTAB uses the BiCG polynomial and a product of linear factors in an attempt to smoothen the convergence. In many cases, this has proven to be very effective. Unfortunately, the convergence of BiCGSTAB may stall when a linear factor (nearly) degenerates. BiCGstab({ell}) is designed to overcome this degeneration of linear factors. It generalizes BiCGSTAB and uses both the BiCG polynomial and a product of higher order factors. Still, CGS may converge faster than BiCGSTAB or BiCGstab({ell}). So instead of using a product of linear or higher order factors, it may be worthwhile to look for other polynomials. Since the BiCG polynomial is based on a three term recursion, a natural choice would be a polynomial based on another three term recursion. Possibly, a suitable choice of recursion coefficients would result in method that converges faster or as fast as CGS, but less erratic. It turns out that an algorithm for such a method can easily be formulated. One particular choice for the recursion coefficients leads to CGS. Therefore one could call this algorithm generalized CGS. Another choice for the recursion coefficients leads to BiCGSTAB. It is therefore possible to mix linear factors and some polynomial based on a three term recursion. This way one may get the best of both worlds. The authors will report on their findings.

  8. Data acquisition for sensor systems

    CERN Document Server

    Taylor, H Rosemary


    'Data acquisition' is concerned with taking one or more analogue signals and converting them to digital form with sufficient accu­ racy and speed to be ready for processing by a computer. The increasing use of computers makes this an expanding field, and it is important that the conversion process is done correctly because information lost at this stage can never be regained, no matter how good the computation. The old saying - garbage in, garbage out - is very relevant to data acquisition, and so every part of the book contains a discussion of errors: where do they come from, how large are they, and what can be done to reduce them? The book aims to treat the data acquisition process in depth with less detailed chapters on the fundamental principles of measure­ ment, sensors and signal conditioning. There is also a chapter on software packages, which are becoming increasingly popular. This is such a rapidly changing topic that any review of available pro­ grams is bound to be out of date before the book re...

  9. Mergers by Partial Acquisition


    Lindqvist, Tobias


    This paper evaluates partial acquisition strategies. The model allows for buying a share of a firm before the actual acquisition takes place. Holding a share in a competing firm before the acquisition of another firm, outsider-toehold, eliminates the insiders' dilemma, i.e. profitable mergers do not occur. This strategy may thus be more profitable for a buyer than acquiring entire firms at once. Furthermore, the insiders' dilemma arises from the assumption of a positive externality on the out...

  10. Volume T1-weighted gradient echo MRI in multiple sclerosis patients. (United States)

    Shah, M; Ross, J S; VanDyke, C; Rudick, R A; Goodkin, D E; Obuchowski, N; Modic, M T


    Three-dimensional (3D) volume turbo fast low angle shot (FLASH) techniques have become available which produce heavily T1-weighted images, similar to inversion recovery scans, utilizing the appropriate flip angle and inversion time. The purpose of this study was to compare the sensitivity of a rapid volume gradient echo technique [3D magnetization prepared rapid acquisition gradient echo (MP RAGE)] in identifying multiple sclerosis (MS) plaques with a conventional T2-weighted spin echo (SE) sequence. Ten patients with clinical MS were evaluated. Patients underwent a routine examination consisting of an axial T2-weighted SE sequence (2,500,22/90) and a coronal 3D MP RAGE, 10/4/10, acquired as 128 two mm partitions. In six patients, area measurements of 22 plaques were determined on both the axial T2-weighted SE examinations and the axial reformatted MP RAGE examinations. The overall number of plaques utilizing each technique was approximately the same. One hundred twenty-two plaques were visualized for the 3D MP RAGE sequence, and 128 plaques for the T2-weighted SE sequence. There were differences in detection of plaques in different regions, with plaques in gray matter better demonstrated utilizing the conventional T2-weighted SE sequence. Plaques in the corpus callosum, pons, and brachia pontis were better demonstrated utilizing 3D MP RAGE. No significant difference was found between the areas measured on the MP RAGE sequence and on the T2-weighted SE sequence. Three-dimensional MP RAGE provides a sensitive and complementary method to conventional T2-weighted SE sequences in the evaluation of patients with MS.

  11. Gradient Boosting Machines, A Tutorial

    Directory of Open Access Journals (Sweden)

    Alexey eNatekin


    Full Text Available Gradient boosting machines are a family of powerful machine-learning techniques that have shown considerable success in a wide range of practical applications. They are highly customizable to the particular needs of the application, like being learned with respect to different loss functions. This article gives a tutorial introduction into the methodology of gradient boosting methods. A theoretical information is complemented with many descriptive examples and illustrations which cover all the stages of the gradient boosting model design. Considerations on handling the model complexity are discussed. A set of practical examples of gradient boosting applications are presented and comprehensively analyzed.

  12. Design of a large dynamics fast acquisition device: application to readout of the electromagnetic calorimeter in the ATLAS experiment; Conception d`un dispositif d`acquisition rapide de grande dynamique: application a la lecture du calorimetre electromagnetique de l`experience ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Bussat, Jean-Marie [Universite de Paris Sud, 91 - Orsay (France)


    The construction of the new particle accelerator, the LHC (Large Hadron Collider) at CERN is entails many research and development projects. It is the case in electronics where the problem of the acquisition of large dynamic range signals at high sampling frequencies occurs. Typically, the requirements are a dynamic range of about 65,000 (around 16 bits) at 40 MHz. Some solutions to this problem will be presented. One of them is using a commercial analog-to-digital converter. This case brings up the necessity of a signal conditioning equipment. This thesis describes a way of building such a system that will be called `multi-gain system`. Then, an application of this method is presented. It involves the realization of an automatic gain switching integrated circuit. It is designed for the readout of the ATLAS electromagnetic calorimeter. The choice and the calculation of the components of this systems are described. They are followed by the results of some measurements done on a prototype made using the AMS 1.2{mu}m BiCMOS foundry. Possible enhancements are also presented. We conclude on the feasibility of such a system and its various applications in a number of fields that are not restricted to particle physics. (author) 33 refs., 132 figs., 22 tabs.

  13. Learning to expand internationally : The pace and success of foreign acquisitions

    NARCIS (Netherlands)

    Nadolska, A.


    In an era of rapid technological progress and major political and economic transformations accross the globe, the ability to acquire internationally becomes an important skill for internationalizing companies. Cross border mergers and acquisitions are growing rapidly in importance precisely becuase

  14. Acquisition Research Program Homepage



    Includes an image of the main page on this date and compressed file containing additional web pages. Established in 2003, Naval Postgraduate School’s (NPS) Acquisition Research Program provides leadership in innovation, creative problem solving and an ongoing dialogue, contributing to the evolution of Department of Defense acquisition strategies.

  15. Acquisition of teleological descriptions (United States)

    Franke, David W.


    Teleology descriptions capture the purpose of an entity, mechanism, or activity with which they are associated. These descriptions can be used in explanation, diagnosis, and design reuse. We describe a technique for acquiring teleological descriptions expressed in the teleology language TeD. Acquisition occurs during design by observing design modifications and design verification. We demonstrate the acquisition technique in an electronic circuit design.

  16. Robotization in Seismic Acquisition

    NARCIS (Netherlands)

    Blacquière, G.; Berkhout, A.J.


    The amount of sources and detectors in the seismic method follows "Moore’s Law of seismic data acquisition", i.e., it increases approximately by a factor of 10 every 10 years. Therefore automation is unavoidable, leading to robotization of seismic data acquisition. Recently, we introduced a new

  17. Strain gradients in epitaxial ferroelectrics

    NARCIS (Netherlands)

    Catalan, G; Noheda, Beatriz; McAneney, J; Sinnamon, LJ; Gregg, JM


    X-ray analysis of ferroelectric thin layers of Ba1/2Sr1/2TiO3 with different thicknesses reveals the presence of strain gradients across the films and allows us to propose a functional form for the internal strain profile. We use this to calculate the influence of strain gradient, through

  18. Computational Strain Gradient Crystal Plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.


    A model for strain gradient crystal visco-plasticity is formulated along the lines proposed by Fleck andWillis (2009) for isotropic plasticity. Size-effects are included in the model due to the addition of gradient terms in both the free energy as well as through a dissipation potential. A finite...

  19. Sobolev gradients and differential equations

    CERN Document Server

    Neuberger, J W


    A Sobolev gradient of a real-valued functional on a Hilbert space is a gradient of that functional taken relative to an underlying Sobolev norm. This book shows how descent methods using such gradients allow a unified treatment of a wide variety of problems in differential equations. For discrete versions of partial differential equations, corresponding Sobolev gradients are seen to be vastly more efficient than ordinary gradients. In fact, descent methods with these gradients generally scale linearly with the number of grid points, in sharp contrast with the use of ordinary gradients. Aside from the first edition of this work, this is the only known account of Sobolev gradients in book form. Most of the applications in this book have emerged since the first edition was published some twelve years ago. What remains of the first edition has been extensively revised. There are a number of plots of results from calculations and a sample MatLab code is included for a simple problem. Those working through a fair p...

  20. The application of polymerase chain reaction-denaturing gradient ...

    African Journals Online (AJOL)

    A rapid microbial screening method was developed based on denaturing gradient gel electrophoresis (DGGE). To evaluate the repeatability and reliability of this system, three DGGE markers were used. Then, the feasibility of DGGE method was verified by microbial screenings in viili (a traditional fermented dairy product ...

  1. Mergers and Acquisitions

    DEFF Research Database (Denmark)

    Risberg, Annette

    Introduction to the study of mergers and acquisitions. This book provides an understanding of the mergers and acquisitions process, how and why they occur, and also the broader implications for organizations. It presents issues including motives and planning, partner selection, integration......, employee experiences and communication. Mergers and acquisitions remain one of the most common forms of growth, yet they present considerable challenges for the companies and management involved. The effects on stakeholders, including shareholders, managers and employees, must be considered as well...... by editorial commentaries and reflects the important organizational and behavioural aspects which have often been ignored in the past. By providing this in-depth understanding of the mergers and acquisitions process, the reader understands not only how and why mergers and acquisitions occur, but also...

  2. Charge gradient microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Roelofs, Andreas; Hong, Seungbum


    A method for rapid imaging of a material specimen includes positioning a tip to contact the material specimen, and applying a force to a surface of the material specimen via the tip. In addition, the method includes moving the tip across the surface of the material specimen while removing electrical charge therefrom, generating a signal produced by contact between the tip and the surface, and detecting, based on the data, the removed electrical charge induced through the tip during movement of the tip across the surface. The method further includes measuring the detected electrical charge.

  3. Advanced compositional gradient and compartmentalization analysis

    Energy Technology Data Exchange (ETDEWEB)

    Canas, Jesus A.; Petti, Daniela; Mullins, Oliver [Schlumberger Servicos de Petroleo Ltda., Rio de Janeiro, RJ (Brazil)


    Acquisition of hydrocarbons samples from the reservoir prior to oil or gas production is essential in order to design production strategies and production facilities. In addition, reservoir compartmentalization and hydrocarbon compositional grading magnify the necessity to map fluid properties vertically and laterally in the reservoir prior to production. Formation testers supply a wealth of information to observe and predict the state of fluids in hydrocarbon reservoirs, through detailed pressure and fluid analysis measurements. With the correct understanding of the state of fluids in the reservoirs, reserve calculations and adequate development plans can be prepared. Additionally, flow barriers may then be revealed. This paper describes a new Downhole Fluid Analysis technology (DFA) for improved reservoir management. DFA is a unique process that combines new fluid identification sensors, which allow real time monitoring of a wide range of parameters as GOR, fluid density, viscosity, fluorescence and composition (CH{sub 4}, C2- C5, C6 +, CO{sub 2}), free gas and liquid phases detection, saturation pressure, as well WBM and OBM filtrate differentiation and pH. This process is not limited to light fluid evaluation and we extended to heavy oil (HO) reservoirs analysis successfully. The combination of DFA Fluid Profiling with pressure measurements has shown to be very effective for compartmentalization characterization. The ability of thin barriers to hold off large depletion pressures has been established, as the gradual variation of hydrocarbon quality in biodegraded oils. In addition, heavy oils can show large compositional variation due to variations in source rock charging but without fluid mixing. Our findings indicates that steep gradients are common in gas condensates or volatile oils, and that biodegradation is more common in HO than in other hydrocarbons, which generate fluid gradients and heavy ends tars near the OWC, limiting the aquifer activity and

  4. Gradient elution in capillary electrochromatography

    Energy Technology Data Exchange (ETDEWEB)

    Anex, D.; Rakestraw, D.J. [Sandia National Labs., Livermore, CA (United States); Yan, Chao; Dadoo, R.; Zare, R.N. [Stanford Univ., CA (United States). Dept. of Chemistry


    In analogy to pressure-driven gradient techniques in high-performance liquid chromatography, a system has been developed for delivering electroosmotically-driven solvent gradients for capillary electrochromatography (CEC). Dynamic gradients with sub-mL/min flow rates are generated by merging two electroosmotic flows that are regulated by computer-controlled voltages. These flows are delivered by two fused-silica capillary arms attached to a T-connector, where they mix and then flow into a capillary column that has been electrokinetically packed with 3-mm reversed-phase particles. The inlet of one capillary arm is placed in a solution reservoir containing one mobile phase and the inlet of the other is placed in a second reservoir containing a second mobile phase. Two independent computer-controlled programmable high-voltage power supplies (0-50 kV)--one providing an increasing ramp and the other providing a decreasing ramp--are used to apply variable high-voltage potentials to the mobile phase reservoirs to regulate the electroosmotic flow in each arm. The ratio of the electroosmotic flow rates between the two arms is changed with time according to the computer-controlled voltages to deliver the required gradient profile to the separation column. Experiments were performed to confirm the composition of the mobile phase during a gradient run and to determine the change of the composition in response to the programmed voltage profile. To demonstrate the performance of electroosmotically-driven gradient elution in CEC, a mixture of 16 polycyclic aromatic hydrocarbons (PAHs) was separated in less than 90 minutes. This gradient technique is expected to be well-suited for generating not only solvent gradients in CEC, but also other types of gradients such as pH- and ionic-strength gradients in capillary electrokinetic separations and analyses.

  5. Simultaneous perfusion and permeability measurements using combined spin- and gradient-echo MRI


    Schmiedeskamp, Heiko; Andre, Jalal B; Straka, Matus; Christen, Thomas; Nagpal, Seema; Recht, Lawrence; Thomas, Reena P; Zaharchuk, Greg; Bammer, Roland


    The purpose of this study was to estimate magnetic resonance imaging-based brain perfusion parameters from combined multiecho spin-echo and gradient-echo acquisitions, to correct them for T1-, T2-, and -related contrast agent (CA) extravasation effects, and to simultaneously determine vascular permeability. Perfusion data were acquired using a combined multiecho spin- and gradient-echo (SAGE) echo-planar imaging sequence, which was corrected for CA extravasation effects using pharmacokinetic ...

  6. Gradient zone boundary control in salt gradient solar ponds

    Energy Technology Data Exchange (ETDEWEB)

    Hull, John R. (Downers Grove, IL)


    A method and apparatus for suppressing zone boundary migration in a salt gradient solar pond includes extending perforated membranes across the pond at the boundaries, between the convective and non-convective zones, the perforations being small enough in size to prevent individual turbulence disturbances from penetrating the hole, but being large enough to allow easy molecular diffusion of salt thereby preventing the formation of convective zones in the gradient layer. The total area of the perforations is a sizable fraction of the membrane area to allow sufficient salt diffusion while preventing turbulent entrainment into the gradient zone.


    Directory of Open Access Journals (Sweden)



    Full Text Available Armijo rule is an inexact line search method to determine step size in some descent method to solve unconstrained local optimization. Modified Armijo was introduced to increase the numerical performance of several descent algorithms that applying this method. The basic difference of Armijo and its modified are in existence of a parameter and estimating the parameter that is updated in every iteration. This article is comparing numerical solution and time of computation of gradient descent and conjugate gradient hybrid Gilbert-Nocedal (CGHGN that applying modified Armijo rule. From program implementation in Matlab 6, it's known that gradient descent was applying modified Armijo more effectively than CGHGN from one side: iteration needed to reach some norm of the gradient  (input by the user. The amount of iteration was representing how long the step size of each algorithm in each iteration. In another side, time of computation has the same conclusion.

  8. Interactive knowledge acquisition tools (United States)

    Dudziak, Martin J.; Feinstein, Jerald L.


    The problems of designing practical tools to aid the knowledge engineer and general applications used in performing knowledge acquisition tasks are discussed. A particular approach was developed for the class of knowledge acquisition problem characterized by situations where acquisition and transformation of domain expertise are often bottlenecks in systems development. An explanation is given on how the tool and underlying software engineering principles can be extended to provide a flexible set of tools that allow the application specialist to build highly customized knowledge-based applications.

  9. Indexing mergers and acquisitions


    Gang, Jianhua; Guo, Jie (Michael); Hu, Nan; Li, Xi


    We measure the efficiency of mergers and acquisitions by putting forward an index (the ‘M&A Index’) based on stochastic frontier analysis. The M&A Index is calculated for each takeover deal and is standardized between 0 and 1. An acquisition with a higher index encompasses higher efficiency. We find that takeover bids with higher M&A Indices are more likely to succeed. Moreover, the M&A Index shows a strong and positive relation with the acquirers’ post-acquisition stock perfo...

  10. The geomagnetic field gradient tensor

    DEFF Research Database (Denmark)

    Kotsiaros, Stavros; Olsen, Nils


    of the magnetic gradient tensor and provide explicit expressions of its elements in terms of spherical harmonics. Finally we discuss the benefit of using gradient measurements for exploring the Earth’s magnetic field from space, in particular the advantage of the various tensor elements for a better determination......We develop the general mathematical basis for space magnetic gradiometry in spherical coordinates. The magnetic gradient tensor is a second rank tensor consisting of 3 × 3 = 9 spatial derivatives. Since the geomagnetic field vector B is always solenoidal (∇ · B = 0) there are only eight independent...

  11. When less is more: a simple Western blotting amendment allowing data acquisition on human single fibers

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Richter, Erik


    This editorial discusses a simple western blotting-amendment allowing rapid data-acquisition on single fibers obtained from freeze-dried human skeletal muscle biopsies.......This editorial discusses a simple western blotting-amendment allowing rapid data-acquisition on single fibers obtained from freeze-dried human skeletal muscle biopsies....

  12. Acquisition Workforce Annual Report 2006 (United States)

    General Services Administration — This is the Federal Acquisition Institute's (FAI's) Annual demographic report on the Federal acquisition workforce, showing trends by occupational series, employment...

  13. Acquisition Workforce Annual Report 2008 (United States)

    General Services Administration — This is the Federal Acquisition Institute's (FAI's) Annual demographic report on the Federal acquisition workforce, showing trends by occupational series, employment...

  14. FWS Approved Acquisition Boundaries (United States)

    US Fish and Wildlife Service, Department of the Interior — This data layer depicts the external boundaries of lands and waters that are approved for acquisition by the U.S. Fish and Wildlife Service (USFWS) in North America,...

  15. Documentation and knowledge acquisition (United States)

    Rochowiak, Daniel; Moseley, Warren


    Traditional approaches to knowledge acquisition have focused on interviews. An alternative focuses on the documentation associated with a domain. Adopting a documentation approach provides some advantages during familiarization. A knowledge management tool was constructed to gain these advantages.

  16. Acquisition IT Integration

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Øhrgaard, Christian


    The IT integration of acquisitions consists an important challenge for the many acquiring organizations. Complementing existing research, this paper searches for explanation to differences in acquirers’ abilities for acquisition IT integration in the external of the acquirer, by a study of the use...... of temporary agency workers. Following an analytic induction approach, theoretically grounded in the re-source-based view of the firm, we identify the complimentary and supplementary roles consultants can assume in acquisition IT integration. Through case studies of three acquirers, we investigate how...... the acquirers appropriate the use of agency workers as part of its acquisition strategy. For the investigated acquirers, assigning roles to agency workers is contingent on balancing the needs of knowledge induction and knowledge retention, as well as experience richness and in-depth under-standing. Composition...

  17. Multiple half-second acquisition method of the moving knee joint. Kinematic MR imaging of the anterior cruciate ligament

    Energy Technology Data Exchange (ETDEWEB)

    Niitsu, Mamoru; Ikeda, Kotaroh; Fukubayashi, Tohru; Echigo, Junko; Itai, Yuji [Tsukuba Univ., Ibaraki (Japan). Inst. of Clinical Medicine


    The objective of this study was to delineate the moving anterior cruciate ligament (ACL) with multiple rapid magnetic resonance (MR) imaging. Rapid gradient echo MR images with an one-shot acquisition time of a half-second were accomplished by short repetition time and phase encoding reduction. Using a mobile knee brace and a flexible surface coil, half-second acquisitions were sequentially acquired during active, constant knee movement. Sixteen knees with intact ACLs and 27 knees with arthroscopically proven ACL tears were examined. Normal ACLs were identified as moving linear low-intensities. The ligaments were readily identified as straight or minimally curved structures when the knee was in semi-flexion compared to the knee extension. Torn ACLs were demonstrated as moving fragments or an amorphous configuration. Intermittent appearances of joint fluid interrupted the ligamentous continuities. Compared to the static images, no significant superiority of the kinematic imaging was found in diagnosis of ACL tears. However, this instant kinematic imaging is feasible with a standard MR system and can provide morphological information for functional analysis of the knee. (author)

  18. Sobolev gradients and differential equations

    CERN Document Server

    Neuberger, John William


    A Sobolev gradient of a real-valued functional is a gradient of that functional taken relative to the underlying Sobolev norm. This book shows how descent methods using such gradients allow a unified treatment of a wide variety of problems in differential equations. Equal emphasis is placed on numerical and theoretical matters. Several concrete applications are made to illustrate the method. These applications include (1) Ginzburg-Landau functionals of superconductivity, (2) problems of transonic flow in which type depends locally on nonlinearities, and (3) minimal surface problems. Sobolev gradient constructions rely on a study of orthogonal projections onto graphs of closed densely defined linear transformations from one Hilbert space to another. These developments use work of Weyl, von Neumann and Beurling.

  19. Graded/Gradient Porous Biomaterials

    Directory of Open Access Journals (Sweden)

    Xigeng Miao


    Full Text Available Biomaterials include bioceramics, biometals, biopolymers and biocomposites and they play important roles in the replacement and regeneration of human tissues. However, dense bioceramics and dense biometals pose the problem of stress shielding due to their high Young’s moduli compared to those of bones. On the other hand, porous biomaterials exhibit the potential of bone ingrowth, which will depend on porous parameters such as pore size, pore interconnectivity, and porosity. Unfortunately, a highly porous biomaterial results in poor mechanical properties. To optimise the mechanical and the biological properties, porous biomaterials with graded/gradient porosity, pores size, and/or composition have been developed. Graded/gradient porous biomaterials have many advantages over graded/gradient dense biomaterials and uniform or homogenous porous biomaterials. The internal pore surfaces of graded/gradient porous biomaterials can be modified with organic, inorganic, or biological coatings and the internal pores themselves can also be filled with biocompatible and biodegradable materials or living cells. However, graded/gradient porous biomaterials are generally more difficult to fabricate than uniform or homogenous porous biomaterials. With the development of cost-effective processing techniques, graded/gradient porous biomaterials can find wide applications in bone defect filling, implant fixation, bone replacement, drug delivery, and tissue engineering.

  20. Prostate treatments, 1MRT o RapidArc; Tratamiento de prostata, IMART o RapidArc?

    Energy Technology Data Exchange (ETDEWEB)

    Castro novais, J.; Ruiz Maqueda, S.; Pardo Perez, E.; Molina Lopez, M. Y.; Cerro Penalver, E.


    Techniques that modulate the dose (as IMRT or RapidArcTM) improve dose homogeneity within the target volume decreasing the dose in healthy organs. The aim of this work is to study the dosimetric differences in prostate radiotherapy treatments with IMRT and RapidArcTM. The results of the 109 patients studied show that plans to RapidArcTM have better coverage, compliance and dose gradient outside the target volume. (Author)

  1. Mergers & acquisitions : an entertainment and media conglomerate


    Plumen, Kevin Jürgen


    The entertainment and media landscape is considered as a rapidly changing and highly growing industry. Due to increasing M&A activity and changing consumer demand for experiences and interactions with high-quality content, entertainment and media companies are advised to innovate their products and user experience with focus on digitalization. This thesis considers an acquisition of Time Warner by 21st Century Fox, two of the biggest companies in the entertainment and media industry. First of...

  2. Rapid imaging of free radicals in vivo using field cycled PEDRI. (United States)

    Puwanich, P; Lurie, D J; Foster, M A


    Imaging of free radicals in vivo using an interleaved field-cycled proton-electron double-resonance imaging (FC-PEDRI) pulse sequence has recently been investigated. In this work, in order to reduce the EPR (electron paramagnetic resonance) irradiation power required and the imaging time, a centric reordered snapshot FC-PEDRI pulse sequence has been implemented. This is based on the FLASH pulse sequence with a very short repetition time and the use of centric reordering of the phase-encoding gradient, allowing the most significant free induction decay (FID) signals to be collected before the signal enhancement decays significantly. A new technique of signal phaseshift correction was required to eliminate ghost artefacts caused by the instability of the main magnetic field after field cycling. An FID amplitude correction scheme has also been implemented to reduce edge enhancement artefacts caused by the rapid change of magnetization population before reaching the steady state. Using the rapid pulse sequence, the time required for acquisition of a 64 x 64 pixel FC-PEDRI image was reduced to 6 s per image compared with about 2.5 min with the conventional pulse sequence. The EPR irradiation power applied to the sample was reduced by a factor of approximately 64. Although the resulting images obtained by the rapid pulse sequence have a lower signal to noise than those obtained by a normal interleaved FC-PEDRI pulse sequence, the results show that rapid imaging of free radicals in vivo using snapshot FC-PEDRI is possible.

  3. Rapid Acquisition Imaging Spectrograph (RAISE) Renewal Proposal Project (United States)

    National Aeronautics and Space Administration — The optical design of RAISE is based on a new class of UV/EUV imaging spectrometers that use  only two reflections to provide quasi-stigmatic performance...

  4. Post-Acquisition IT Integration

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Yetton, Philip


    The extant research on post-acquisition IT integration analyzes how acquirers realize IT-based value in individual acquisitions. However, serial acquirers make 60% of acquisitions. These acquisitions are not isolated events, but are components in growth-by-acquisition programs. To explain how...... serial acquirers realize IT-based value, we develop three propositions on the sequential effects on post-acquisition IT integration in acquisition programs. Their combined explanation is that serial acquirers must have a growth-by-acquisition strategy that includes the capability to improve...... IT integration capabilities, to sustain high alignment across acquisitions and to maintain a scalable IT infrastructure with a flat or decreasing cost structure. We begin the process of validating the three propositions by investigating a longitudinal case study of a growth-by-acquisition program....

  5. Rapid Prototyping (United States)


    Javelin, a Lone Peak Engineering Inc. Company has introduced the SteamRoller(TM) System as a commercial product. The system was designed by Javelin during a Phase II NASA funded small commercial product. The purpose of the invention was to allow automated-feed of flexible ceramic tapes to the Laminated Object Manufacturing rapid prototyping equipment. The ceramic material that Javelin was working with during the Phase II project is silicon nitride. This engineered ceramic material is of interest for space-based component.

  6. Acquisition of Romance languages. Introduction


    Gavarró, Anna


    Generative grammar addressed for the first time acquisition as a central issue in the study of grammar. This perspective has given rise over the years to a considerable body of work, mainly on first language acquisition, but also on second language acquistion, bilingual acquisition, and the acquisition by children affected by SLI. If we assume continuity, i.e. that all stages in acquisition reflect possible natural languages, we must posit a mutual dependency between grammatical theory and th...

  7. PET/MR Synchronization by Detection of Switching Gradients (United States)

    Weissler, Bjoern; Gebhardt, Pierre; Lerche, Christoph W.; Soultanidis, Georgios M.; Wehner, Jakob; Heberling, Dirk; Schulz, Volkmar


    The full potential of simultaneous Positron Emission Tomography (PET) and Magnetic Resonance Imaging (MRI) acquisition, such as dynamic studies or motion compensation, can only be explored if the data of both modalities is temporally synchronized. As such hybrid imaging systems are commonly realized as custom-made PET inserts for commercially available MRI scanner, a synchronization solution has to be implemented (depending on the vendor of the MRI system). In contrast, we demonstrate a simple method for temporal synchronization, which does not require a connection to the MRI. It uses the normally undesired effect of induced voltages on the PET electronics from switching MRI gradients. The electronic circuit needs very few components and the gradient pick-up coils are made from PCB traces and vias on the PET detector boards. Neither programming the MRI nor any physical connection to the MR scanner is needed, thus avoiding electromagnetic compatibility problems. This method works inherently with most MRI sequences and is a vendor- independent solution. A characterization of the sensors in an MRI scanner showed that the MRI gradients are detected with a precision of 120 μs (with the current implementation). Using different trigger thresholds, it is possible to trigger selectively on certain MRI sequences, depending on their gradient slew rate settings. Timings and pulse diagrams of MRI sequences can be recognized from the generated data. The method was successfully used for temporal alignment between PET and MRI in an MRI-based PET-motion-compensation application.

  8. TIGER: Development of Thermal Gradient Compensation Algorithms and Techniques (United States)

    Hereford, James; Parker, Peter A.; Rhew, Ray D.


    In a wind tunnel facility, the direct measurement of forces and moments induced on the model are performed by a force measurement balance. The measurement balance is a precision-machined device that has strain gages at strategic locations to measure the strain (i.e., deformations) due to applied forces and moments. The strain gages convert the strain (and hence the applied force) to an electrical voltage that is measured by external instruments. To address the problem of thermal gradients on the force measurement balance NASA-LaRC has initiated a research program called TIGER - Thermally-Induced Gradients Effects Research. The ultimate goals of the TIGER program are to: (a) understand the physics of the thermally-induced strain and its subsequent impact on load measurements and (b) develop a robust thermal gradient compensation technique. This paper will discuss the impact of thermal gradients on force measurement balances, specific aspects of the TIGER program (the design of a special-purpose balance, data acquisition and data analysis challenges), and give an overall summary.

  9. Knowledge Transfers following Acquisition

    DEFF Research Database (Denmark)

    Gammelgaard, Jens


    study of 54 Danish acquisitions taking place abroad from 1994 to 1998 demonstrated that when there was a high level of trust between the acquiring firm and the target firm before the take-over, then medium and strong tie-binding knowledge transfer mechanisms, such as project groups and job rotation......Prior relations between the acquiring firm and the target company pave the way for knowledge transfers subsequent to the acquisitions. One major reason is that through the market-based relations the two actors build up mutual trust and simultaneously they learn how to communicate. An empirical...

  10. Gradient language dominance affects talker learning. (United States)

    Bregman, Micah R; Creel, Sarah C


    Traditional conceptions of spoken language assume that speech recognition and talker identification are computed separately. Neuropsychological and neuroimaging studies imply some separation between the two faculties, but recent perceptual studies suggest better talker recognition in familiar languages than unfamiliar languages. A familiar-language benefit in talker recognition potentially implies strong ties between the two domains. However, little is known about the nature of this language familiarity effect. The current study investigated the relationship between speech and talker processing by assessing bilingual and monolingual listeners' ability to learn voices as a function of language familiarity and age of acquisition. Two effects emerged. First, bilinguals learned to recognize talkers in their first language (Korean) more rapidly than they learned to recognize talkers in their second language (English), while English-speaking participants showed the opposite pattern (learning English talkers faster than Korean talkers). Second, bilinguals' learning rate for talkers in their second language (English) correlated with age of English acquisition. Taken together, these results suggest that language background materially affects talker encoding, implying a tight relationship between speech and talker representations. Copyright © 2013 Elsevier B.V. All rights reserved.

  11. Humans copy rapidly increasing choices in a multiarmed bandit problem

    NARCIS (Netherlands)

    Toelch, U.; Bruce, M.J.; Meeus, M.T.H.; Reader, S.M.


    Conformist social learning, the tendency to acquire the most common trait in a group, allows individuals to rapidly acquire established beneficial traits from a multitude of options. However, conformist strategies hinder acquisition of novel advantageous behavior patterns, because such innovations

  12. Autonomous Robot Skill Acquisition (United States)


    single demonstration using either a learned Hidden Markov Model (HMM) (Pook and Ballard, 1993; Hovland et al., 1996; Dixon and Khosla, 2004) or...of the Nineteenth International Conference on Machine Learning, pages 243– 250. Hovland , G., Sikka, P., and McCarragher, B. (1996). Skill acquisition

  13. Leading Acquisition Reform (United States)


    Army and Undersecretary of Defense for Acquisition, for a reduction of the Excalibur and Accelerated Precision Mortar initiative rounds.25...Can’t Dance? Leading a Great Enterprise Through Dramatic Change, (New York: HarperCollins Publishers, 2003), 235. 13 John P. Kotter , Leading Change

  14. Merger and acquisition medicine. (United States)

    Powell, G S


    This discussion of the ramifications of corporate mergers and acquisitions for employees recognizes that employee adaptation to the change can be a long and complex process. The author describes a role the occupational physician can take in helping to minimize the potential adverse health impact of major organizational change.

  15. Acquisition reconfiguration capability

    NARCIS (Netherlands)

    Amiryany Araghy, N.; Huysman, M.H.; de Man, A.P.; Cloodt, M.


    Purpose: Acquiring knowledge-intensive firms in order to gain access to their knowledge to innovate is not a strategy to achieve easily. Knowledge acquisitions demand that organizations integrate various dispersed knowledge-based resources and thus share knowledge to innovate. However, despite the

  16. Competencies: requirements and acquisition

    NARCIS (Netherlands)

    Kuenn, A.C.; Meng, C.M.; Peters, Z.; Verhagen, A.M.C.


    Higher education is given the key task to prepare the highly talented among the young to fulfil highly qualified roles in the labour market. Successful labour market performance of graduates is generally associated with the acquisition of the correct competencies. Education as an individual

  17. Surviving mergers & acquisitions. (United States)

    Dixon, Diane L


    Mergers and acquisitions are never easy to implement. The health care landscape is a minefield of failed mergers and uneasy alliances generating great turmoil and pain. But some mergers have been successful, creating health systems that benefit the communities they serve. Five prominent leaders offer their advice on minimizing the difficulties of M&As.

  18. Improved T2* imaging without increase in scan time: SWI processing of 2D gradient echo. (United States)

    Soman, S; Holdsworth, S J; Barnes, P D; Rosenberg, J; Andre, J B; Bammer, R; Yeom, K W


    2D gradient-echo imaging is sensitive to T2* lesions (hemorrhages, mineralization, and vascular lesions), and susceptibility-weighted imaging is even more sensitive, but at the cost of additional scan time (SWI: 5-10 minutes; 2D gradient-echo: 2 minutes). The long acquisition time of SWI may pose challenges in motion-prone patients. We hypothesized that 2D SWI/phase unwrapped images processed from 2D gradient-echo imaging could improve T2* lesion detection. 2D gradient-echo brain images of 50 consecutive pediatric patients (mean age, 8 years) acquired at 3T were retrospectively processed to generate 2D SWI/phase unwrapped images. The 2D gradient-echo and 2D SWI/phase unwrapped images were compared for various imaging parameters and were scored in a blinded fashion. Of 50 patients, 2D gradient-echo imaging detected T2* lesions in 29 patients and had normal findings in 21 patients. 2D SWI was more sensitive than standard 2D gradient-echo imaging in detecting T2* lesions (P echo images were more sensitive in detecting T2* lesions and delineating normal venous structures and nonpathologic mineralization, and they also helped distinguish calcification at no additional scan time. SWI processing of 2D gradient-echo images may be a useful adjunct in cases in which longer scan times of 3D SWI are difficult to implement.

  19. A theory of gradient analysis

    NARCIS (Netherlands)

    Braak, ter C.J.F.


    The theory of gradient analysis is presented in this chapter, in which the heuristic techniques are integrated with regression, calibration, ordination and constrained ordination as distinct, well-defined statistical problems. The various techniques used for each type of problem are classified into

  20. Orderings for conjugate gradient preconditionings (United States)

    Ortega, James M.


    The effect of orderings on the rate of convergence of the conjugate gradient method with SSOR or incomplete Cholesky preconditioning is examined. Some results also are presented that help to explain why red/black ordering gives an inferior rate of convergence.

  1. Compositional gradients in Gramineae genes

    DEFF Research Database (Denmark)

    Wong, Gane Ka-Shu; Wang, Jun; Tao, Lin


    In this study, we describe a property of Gramineae genes, and perhaps all monocot genes, that is not observed in eudicot genes. Along the direction of transcription, beginning at the junction of the 5'-UTR and the coding region, there are gradients in GC content, codon usage, and amino-acid usage...

  2. Towards rapid prototyped convective microfluidic DNA amplification platform (United States)

    Ajit, Smrithi; Praveen, Hemanth Mithun; Puneeth, S. B.; Dave, Abhishek; Sesham, Bharat; Mohan, K. N.; Goel, Sanket


    Today, Polymerase Chain Reaction (PCR) based DNA amplification plays an indispensable role in the field of biomedical research. Its inherent ability to exponentially amplify sample DNA has proven useful for the identification of virulent pathogens like those causing Multiple Drug-Resistant Tuberculosis (MDR-TB). The intervention of Microfluidics technology has revolutionized the concept of PCR from being a laborious and time consuming process into one that is faster, easily portable and capable of being multifunctional. The Microfluidics based PCR outweighs its traditional counterpart in terms of flexibility of varying reaction rate, operation simplicity, need of a fraction of volume and capability of being integrated with other functional elements. The scope of the present work involves the development of a real-time continuous flow microfluidic device, fabricated by 3D printing-governed rapid prototyping method, eventually leading to an automated and robust platform to process multiple DNA samples for detection of MDRTB-associated mutations. The thermal gradient characteristic to the PCR process is produced using peltier units appropriate to the microfluidic environment fully monitored and controlled by a low cost controller driven by a Data Acquisition System. The process efficiency achieved in the microfluidic environment in terms of output per cycle is expected to be on par with the traditional PCR and capable of earning the additional advantages of being faster and minimizing the handling.

  3. Manganese acquisition by Lactobacillus plantarum

    Energy Technology Data Exchange (ETDEWEB)

    Archibald, F.S.; Duong, M.N.


    Lactobacillus plantarum has an unusually high Mn(II) requirement for growth and accumulated over 30 mM intracellular Mn(II). The acquisition of Mn(II) by L. plantarum occurred via a specific active transport system powered by the transmembrane proton gradient. The Mn(II) uptake system has a K/sub m/ of 0.2 and a V/sub max/ of 24 nmol mg/sup -1/ of protein min/sup -1/. Above a medium Mn(II) concentration of 200, the intracellular Mn(II) level was independent of the medium Mn(II) and unresponsive to oxygen stresses but was reduced by phosphate limitation. At a pH of 5.5, citrate, isocitrate, and cis-aconitate effectively promoted MN(II) uptake, although measurable levels of 1,5-(/sup 14/C)citrate were not accumulated. When cells were presented with equimolar Mn(II) and Cd(II), Cd(II) was preferentially taken up by the Mn(II) transport system. Both Mn(II) and Cd(II) uptake were greatly increased by Mn(II) starvation. Mn(II) uptake by Mn(II)-starved cells was subject to a negative feedback regulatory mechanism functioning less than 1 min after exposure of the cells to Mn(II) and independent of protein synthesis. When presented with a relatively large amount of exogenous Mn(II), Mn(II)-starved cells exhibited a measurable efflux of their internal Mn(II), but the rate was only a small fraction of the maximal Mn(II) uptake rate.

  4. RF merger and acquisition market


    Evgeniya V. Vidishcheva; Merab S. Sichinava; Marina V. Kogan


    The article gives brief characteristic of merger and acquisition market situation in Russia, brings in overview of bargains in 2009–2010. Russian merger and acquisition market is in early stage of development.

  5. RF merger and acquisition market

    Directory of Open Access Journals (Sweden)

    Evgeniya V. Vidishcheva


    Full Text Available The article gives brief characteristic of merger and acquisition market situation in Russia, brings in overview of bargains in 2009–2010. Russian merger and acquisition market is in early stage of development.

  6. Data acquisition instruments: Psychopharmacology

    Energy Technology Data Exchange (ETDEWEB)

    Hartley, D.S. III


    This report contains the results of a Direct Assistance Project performed by Lockheed Martin Energy Systems, Inc., for Dr. K. O. Jobson. The purpose of the project was to perform preliminary analysis of the data acquisition instruments used in the field of psychiatry, with the goal of identifying commonalities of data and strategies for handling and using the data in the most advantageous fashion. Data acquisition instruments from 12 sources were provided by Dr. Jobson. Several commonalities were identified and a potentially useful data strategy is reported here. Analysis of the information collected for utility in performing diagnoses is recommended. In addition, further work is recommended to refine the commonalities into a directly useful computer systems structure.

  7. Amplitudes, acquisition and imaging

    Energy Technology Data Exchange (ETDEWEB)

    Bloor, Robert


    Accurate seismic amplitude information is important for the successful evaluation of many prospects and the importance of such amplitude information is increasing with the advent of time lapse seismic techniques. It is now widely accepted that the proper treatment of amplitudes requires seismic imaging in the form of either time or depth migration. A key factor in seismic imaging is the spatial sampling of the data and its relationship to the imaging algorithms. This presentation demonstrates that acquisition caused spatial sampling irregularity can affect the seismic imaging and perturb amplitudes. Equalization helps to balance the amplitudes, and the dealing strategy improves the imaging further when there are azimuth variations. Equalization and dealiasing can also help with the acquisition irregularities caused by shot and receiver dislocation or missing traces. 2 refs., 2 figs.

  8. Conjoined Constraints and Phonological Acquisition

    Directory of Open Access Journals (Sweden)

    Giovana Bonilha


    Full Text Available Since the start of Optimality Theory (Prince & Smolensky, 1993, research on phonological acquisition has explored the explanatory potential of constraint theories. This study, also based on Optimality Theory, attempts to analyze the acquisition of CVVC syllable structure by Brazilian Portuguese children and addresses the issue of Local Conjunction (Smolensky, 1995, 1997 in research that deals with problems of phonological acquisition.

  9. First Language Acquisition and Teaching (United States)

    Cruz-Ferreira, Madalena


    "First language acquisition" commonly means the acquisition of a single language in childhood, regardless of the number of languages in a child's natural environment. Language acquisition is variously viewed as predetermined, wondrous, a source of concern, and as developing through formal processes. "First language teaching" concerns schooling in…

  10. Internationalize Mergers and Acquisitions


    Zhou, Lili


    As globalization processes, an increasing number of companies use mergers and acquisitions as a tool to achieve company growth in the international business world. The purpose of this thesis is to investigate the process of an international M&A and analyze the factors leading to success. The research started with reviewing different academic theory. The important aspects in both pre-M&A phase and post-M&A phase have been studied in depth. Because of the complexity in international...

  11. Competencies: requirements and acquisition


    Kuenn, A.C.; Meng, C.M.; Peters, Z.; Verhagen, A.M.C.


    Higher education is given the key task to prepare the highly talented among the young to fulfil highly qualified roles in the labour market. Successful labour market performance of graduates is generally associated with the acquisition of the correct competencies. Education as an individual investment in human capital is a viewpoint dating back to the 17th century and the writings of Sir William Petty (1662), and includes later work by Adam Smith (1776). The idea was formalized and brought in...

  12. Second language acquisition. (United States)

    Juffs, Alan


    Second language acquisition (SLA) is a field that investigates child and adult SLA from a variety of theoretical perspectives. This article provides a survey of some key areas of concern including formal generative theory and emergentist theory in the areas of morpho-syntax and phonology. The review details the theoretical stance of the two different approaches to the nature of language: generative linguistics and general cognitive approaches. Some results of key acquisition studies from the two theoretical frameworks are discussed. From a generative perspective, constraints on wh-movement, feature geometry and syllable structure, and morphological development are highlighted. From a general cognitive point of view, the emergence of tense and aspect marking from a prototype account of inherent lexical aspect is reviewed. Reference is made to general cognitive learning theories and to sociocultural theory. The article also reviews individual differences research, specifically debate on the critical period in adult language acquisition, motivation, and memory. Finally, the article discusses the relationship between SLA research and second language pedagogy. Suggestions for further reading from recent handbooks on SLA are provided. WIREs Cogni Sci 2011 2 277-286 DOI: 10.1002/wcs.106 For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

  13. Complexity in language acquisition. (United States)

    Clark, Alexander; Lappin, Shalom


    Learning theory has frequently been applied to language acquisition, but discussion has largely focused on information theoretic problems-in particular on the absence of direct negative evidence. Such arguments typically neglect the probabilistic nature of cognition and learning in general. We argue first that these arguments, and analyses based on them, suffer from a major flaw: they systematically conflate the hypothesis class and the learnable concept class. As a result, they do not allow one to draw significant conclusions about the learner. Second, we claim that the real problem for language learning is the computational complexity of constructing a hypothesis from input data. Studying this problem allows for a more direct approach to the object of study--the language acquisition device-rather than the learnable class of languages, which is epiphenomenal and possibly hard to characterize. The learnability results informed by complexity studies are much more insightful. They strongly suggest that target grammars need to be objective, in the sense that the primitive elements of these grammars are based on objectively definable properties of the language itself. These considerations support the view that language acquisition proceeds primarily through data-driven learning of some form. Copyright © 2013 Cognitive Science Society, Inc.

  14. Vertebrate pressure-gradient receivers

    DEFF Research Database (Denmark)

    Christensen-Dalsgaard, Jakob


    The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum and stro......The eardrums of all terrestrial vertebrates (tetrapods) are connected through Eustachian tubes or interaural canals. In some of the animals, these connections create pressure-gradient directionality, an enhanced directionality by interaction of sound arriving at both sides of the eardrum....... Recent vertebrates form a continuum from perfect interaural transmission (0 dB in a certain frequency band) and pronounced eardrum directionality (30-40 dB) in the lizards, over somewhat attenuated transmission and limited directionality in birds and frogs, to the strongly attenuated interaural...

  15. Computational strain gradient crystal plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Kysar, Jeffrey W.


    oriented face centered cubic crystals are developed in terms of the crystallographic slip parameters. The effect on geometrically necessary dislocation structures introduced by plastic deformation is investigated as a function of the ratio of void radius to plasticity length scale.......A numerical method for viscous strain gradient crystal plasticity theory is presented, which incorporates both energetic and dissipative gradient effects. The underlying minimum principles are discussed as well as convergence properties of the proposed finite element procedure. Three problems...... of plane crystal plasticity are studied: pure shear of a single crystal between rigid platens as well as plastic deformation around cylindrical voids in hexagonal close packed and face centered cubic crystals. Effective in-plane constitutive slip parameters for plane strain deformation of specifically...

  16. Primordial vorticity and gradient expansion

    CERN Document Server

    Giovannini, Massimo


    The evolution equations of the vorticities of the electrons, ions and photons in a pre-decoupling plasma are derived, in a fully inhomogeneous geometry, by combining the general relativistic gradient expansion and the drift approximation within the Adler-Misner-Deser decomposition. The vorticity transfer between the different species is discussed in this novel framework and a set of general conservation laws, connecting the vorticities of the three-component plasma with the magnetic field intensity, is derived. After demonstrating that a source of large-scale vorticity resides in the spatial gradients of the geometry and of the electromagnetic sources, the total vorticity is estimated to lowest order in the spatial gradients and by enforcing the validity of the momentum constraint. By acknowledging the current bounds on the tensor to scalar ratio in the (minimal) tensor extension of the $\\Lambda$CDM paradigm the maximal comoving magnetic field induced by the total vorticity turns out to be, at most, of the or...

  17. Microecology: Using Fast-Growing Filamentous Fungi to Study the Effects of Environmental Gradients on the Growth Patterns of Hyphae (United States)

    Delpech, Roger


    This paper describes some simple and rapid techniques for examining the growth responses of fungal hyphae cultivated on environmental gradients. The creation of such gradients using agar-based growth media in petri dishes is explained, along with recommendations for quantitative macroscopic and microscopic measurements. The intention is to provide…

  18. Stereo matching based on census transformation of image gradients (United States)

    Stentoumis, C.; Grammatikopoulos, L.; Kalisperakis, I.; Karras, G.; Petsa, E.


    Although multiple-view matching provides certain significant advantages regarding accuracy, occlusion handling and radiometric fidelity, stereo-matching remains indispensable for a variety of applications; these involve cases when image acquisition requires fixed geometry and limited number of images or speed. Such instances include robotics, autonomous navigation, reconstruction from a limited number of aerial/satellite images, industrial inspection and augmented reality through smart-phones. As a consequence, stereo-matching is a continuously evolving research field with growing variety of applicable scenarios. In this work a novel multi-purpose cost for stereo-matching is proposed, based on census transformation on image gradients and evaluated within a local matching scheme. It is demonstrated that when the census transformation is applied on gradients the invariance of the cost function to changes in illumination (non-linear) is significantly strengthened. The calculated cost values are aggregated through adaptive support regions, based both on cross-skeletons and basic rectangular windows. The matching algorithm is tuned for the parameters in each case. The described matching cost has been evaluated on the Middlebury stereo-vision 2006 datasets, which include changes in illumination and exposure. The tests verify that the census transformation on image gradients indeed results in a more robust cost function, regardless of aggregation strategy.

  19. Learning to use illumination gradients as an unambiguous cue to three dimensional shape.

    Directory of Open Access Journals (Sweden)

    Glen Harding

    Full Text Available The luminance and colour gradients across an image are the result of complex interactions between object shape, material and illumination. Using such variations to infer object shape or surface colour is therefore a difficult problem for the visual system. We know that changes to the shape of an object can affect its perceived colour, and that shading gradients confer a sense of shape. Here we investigate if the visual system is able to effectively utilise these gradients as a cue to shape perception, even when additional cues are not available. We tested shape perception of a folded card object that contained illumination gradients in the form of shading and more subtle effects such as inter-reflections. Our results suggest that observers are able to use the gradients to make consistent shape judgements. In order to do this, observers must be given the opportunity to learn suitable assumptions about the lighting and scene. Using a variety of different training conditions, we demonstrate that learning can occur quickly and requires only coarse information. We also establish that learning does not deliver a trivial mapping between gradient and shape; rather learning leads to the acquisition of assumptions about lighting and scene parameters that subsequently allow for gradients to be used as a shape cue. The perceived shape is shown to be consistent for convex and concave versions of the object that exhibit very different shading, and also similar to that delivered by outline, a largely unrelated cue to shape. Overall our results indicate that, although gradients are less reliable than some other cues, the relationship between gradients and shape can be quickly assessed and the gradients therefore used effectively as a visual shape cue.

  20. 40 CFR 230.25 - Salinity gradients. (United States)


    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Salinity gradients. 230.25 Section 230... Physical and Chemical Characteristics of the Aquatic Ecosystem § 230.25 Salinity gradients. (a) Salinity... fresh or salt water may change existing salinity gradients. For example, partial blocking of the...

  1. Gradient remediability in linear distributed parabolic systems ...

    African Journals Online (AJOL)

    The aim of this paper is the introduction of a new concept that concerned the analysis of a large class of distributed parabolic systems. It is the general concept of gradient remediability. More precisely, we study with respect to the gradient observation, the existence of an input operator (gradient efficient actuators) ensuring ...

  2. The NUSTAR data acquisition

    Energy Technology Data Exchange (ETDEWEB)

    Loeher, B.; Toernqvist, H.T. [TU Darmstadt (Germany); GSI (Germany); Agramunt, J. [IFIC, CSIC (Spain); Bendel, M.; Gernhaeuser, R.; Le Bleis, T.; Winkel, M. [TU Muenchen (Germany); Charpy, A.; Heinz, A.; Johansson, H.T. [Chalmers University of Technology (Sweden); Coleman-Smith, P.; Lazarus, I.H.; Pucknell, V.F.E. [STFC Daresbury (United Kingdom); Czermak, A. [IFJ (Poland); Kurz, N.; Nociforo, C.; Pietri, S.; Schaffner, H.; Simon, H. [GSI (Germany); Scheit, H. [TU Darmstadt (Germany); Taieb, J. [CEA (France)


    The diversity of upcoming experiments within the NUSTAR collaboration, including experiments in storage rings, reactions at relativistic energies and high-precision spectroscopy, is reflected in the diversity of the required detection systems. A challenging task is to incorporate the different needs of individual detectors within the unified NUSTAR Data AcQuisition (NDAQ). NDAQ takes up this challenge by providing a high degree of availability via continuously running systems, high flexibility via experiment-specific configuration files for data streams and trigger logic, distributed timestamps and trigger information on km distances, all built on the solid basis of the GSI Multi-Branch System. NDAQ ensures interoperability between individual NUSTAR detectors and allows merging of formerly separate data streams according to the needs of all experiments, increasing reliability in NUSTAR data acquisition. An overview of the NDAQ infrastructure and the current progress is presented. The NUSTAR (NUclear STructure, Astrophysics and Reactions) collaboration represents one of the four pillars motivating the construction of the international FAIR facility. The diversity of NUSTAR experiments, including experiments in storage rings, reactions at relativistic energies and high-precision spectroscopy, is reflected in the diversity of the required detection systems. A challenging task is to incorporate the different needs of individual detectors and components under the umbrella of the unified NUSTAR Data AQuisition (NDAQ) infrastructure. NDAQ takes up this challenge by providing a high degree of availability via continuously running systems, high flexibility via experiment-specific configuration files for data streams and trigger logic, and distributed time stamps and trigger information on km distances, all built on the solid basis of the GSI Multi-Branch System (MBS). NDAQ ensures interoperability between individual NUSTAR detectors and allows merging of formerly separate

  3. Language Acquisition in Autism Spectrum Disorders: A Developmental Review (United States)

    Eigsti, Inge-Marie; de Marchena, Ashley B.; Schuh, Jillian M.; Kelley, Elizabeth


    This paper reviews the complex literature on language acquisition in the autism spectrum disorders (ASD). Because of the high degree of interest in ASD in the past decade, the field has been changing rapidly, with progress in both basic science and applied clinical areas. In addition, psycholinguistically-trained researchers have increasingly…

  4. The Role of the Acquisitions Librarian in Electronic Resources Management (United States)

    Pomerantz, Sarah B.


    With the ongoing shift to electronic formats for library resources, acquisitions librarians, like the rest of the profession, must adapt to the rapidly changing landscape of electronic resources by keeping up with trends and mastering new skills related to digital publishing, technology, and licensing. The author sought to know what roles…

  5. First language acquisition. (United States)

    Goodluck, Helen


    This article reviews current approaches to first language acquisition, arguing in favor of the theory that attributes to the child an innate knowledge of universal grammar. Such knowledge can accommodate the systematic nature of children's non-adult linguistic behaviors. The relationships between performance devices (mechanisms for comprehension and production of speech), non-linguistic aspects of cognition, and child grammars are also discussed. WIREs Cogn Sci 2011 2 47-54 DOI: 10.1002/wcs.95 For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

  6. Emergence of a Detonation due to an Initial Temperature Gradient (United States)

    Hawa, Takumi; Schwendeman, Donald; Kapila, Ashwani


    Emergence of a detonation in a homogeneous, exothermically reacting medium can be deemed to occur in two phases. The first phase processes the medium so as to create conditions ripe for the onset of detonation. The actual events leading up to preconditioning may vary from one experiment to the next, but typically, at the end of this stage the medium is hot and in a state of nonuniformity. The second phase consists of the actual formation of the detonation wave via chemico-gasdynamic interactions. This phase is analyzed in detail, for an idealized medium with simple, state-sensitive kinetics and a prescribed initial temperature gradient. Depending upon the size of the gradient, there are two distinct pathways to a ZND detonation. For shallow gradients the event begins with a nearly constant-volume localized explosion, followed by the emergence of a supersonic, shockless reaction wave that decelerates to the CJ speed and then rapidly transforms into the ZND structure. For sharp gradients the localized explosion occurs at nearly constant pressure, and the detonation is then formed as a result of an accelerating reaction wave catching up to a shock. Within the second scenario there are further variations. The manner in which the above processes are affected by flow divergence (cylindrical and spherical symmetric cases) is examined as well. The analysis is based on a combination of asymptotics and finely resolved numerics.

  7. Data acquisition and analysis system for the ion microprobe mass analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Darby, D.M.; Cristy, S.S.


    A computer was interfaced to an ion microprobe mass analyzer for more rapid data acquisition and analysis. The interface is designed to allow data acquisition, independent of the computer. A large data analysis package was developed and implemented. Performance of the computerized system was evaluated and compared to manual operation.

  8. Development and dissipation of Ca(2+) gradients in adrenal chromaffin cells. (United States)

    Marengo, F D; Monck, J R


    We used pulsed laser imaging to measure the development and dissipation of Ca(2+) gradients evoked by the activation of voltage-sensitive Ca(2+) channels in adrenal chromaffin cells. Ca(2+) gradients appeared rapidly (buffer capacity on the order of 1000 and appropriate affinity and kinetics, approximated the size of the Ca(2+) increases and rate of dissipation of the measured gradients. Finally, simulations without exogenous buffer suggest that the Ca(2+) signal due to Ca(2+) channel activation is restricted by the endogenous buffer to a space less than 1 microm from the cell membrane. PMID:11023887

  9. Oxygen Gradients in the Microcirculation (United States)

    Pittman, Roland N.


    Early in the last century August Krogh embarked on a series of seminal studies to understand the connection between tissue metabolism and mechanisms by which the cardiovascular system supplied oxygen to meet those needs. Krogh recognized that oxygen was supplied from blood to the tissues by passive diffusion and that the most likely site for oxygen exchange was the capillary network. Studies of tissue oxygen consumption and diffusion coefficient, coupled with anatomical studies of capillarity in various tissues, led him to formulate a model of oxygen diffusion from a single capillary. Fifty years after the publication of this work, new methods were developed which allowed the direct measurement of oxygen in and around microvessels. These direct measurements have confirmed the predictions by Krogh and have led to extensions of his ideas resulting in our current understanding of oxygenation within the microcirculation. Developments during the last 40 years are reviewed, including studies of oxygen gradients in arterioles, capillaries, venules, microvessel wall and surrounding tissue. These measurements were made possible by the development and use of new methods to investigate oxygen in the microcirculation, so mention is made of oxygen microelectrodes, microspectrophotometry of haemoglobin and phosphorescence quenching microscopy. Our understanding of oxygen transport from the perspective of the microcirculation has gone from a consideration of oxygen gradients in capillaries and tissue to the realization that oxygen has the ability to diffuse from any microvessel to another location under the conditions that there exists a large enough PO2 gradient and that the permeability for oxygen along the intervening pathway is sufficient. PMID:21281453

  10. Dai-Kou type conjugate gradient methods with a line search only using gradient. (United States)

    Huang, Yuanyuan; Liu, Changhe


    In this paper, the Dai-Kou type conjugate gradient methods are developed to solve the optimality condition of an unconstrained optimization, they only utilize gradient information and have broader application scope. Under suitable conditions, the developed methods are globally convergent. Numerical tests and comparisons with the PRP+ conjugate gradient method only using gradient show that the methods are efficient.

  11. Stringy bounces and gradient instabilities

    CERN Document Server

    Giovannini, Massimo


    Bouncing solutions are obtained from a generally covariant action characterized by a potential which is a nonlocal functional of the dilaton field at two separated space-time points. Gradient instabilities are shown to arise in this context but they are argued to be nongeneric. After performing a gauge-invariant and frame-invariant derivation of the evolution equations of the fluctuations, a heuristic criterium for the avoidance of pathological instabilities is proposed and corroborated by a number of explicit examples that turn out to be compatible with a quasi-flat spectrum of curvature inhomogeneities for typical wavelengths larger than the Hubble radius.

  12. Continued Data Acquisition Development

    Energy Technology Data Exchange (ETDEWEB)

    Schwellenbach, David [National Security Technologies, LLC. (NSTec), Mercury, NV (United States)


    This task focused on improving techniques for integrating data acquisition of secondary particles correlated in time with detected cosmic-ray muons. Scintillation detectors with Pulse Shape Discrimination (PSD) capability show the most promise as a detector technology based on work in FY13. Typically PSD parameters are determined prior to an experiment and the results are based on these parameters. By saving data in list mode, including the fully digitized waveform, any experiment can effectively be replayed to adjust PSD and other parameters for the best data capture. List mode requires time synchronization of two independent data acquisitions (DAQ) systems: the muon tracker and the particle detector system. Techniques to synchronize these systems were studied. Two basic techniques were identified: real time mode and sequential mode. Real time mode is the preferred system but has proven to be a significant challenge since two FPGA systems with different clocking parameters must be synchronized. Sequential processing is expected to work with virtually any DAQ but requires more post processing to extract the data.

  13. Unsupervised Language Acquisition (United States)

    de Marcken, Carl


    This thesis presents a computational theory of unsupervised language acquisition, precisely defining procedures for learning language from ordinary spoken or written utterances, with no explicit help from a teacher. The theory is based heavily on concepts borrowed from machine learning and statistical estimation. In particular, learning takes place by fitting a stochastic, generative model of language to the evidence. Much of the thesis is devoted to explaining conditions that must hold for this general learning strategy to arrive at linguistically desirable grammars. The thesis introduces a variety of technical innovations, among them a common representation for evidence and grammars, and a learning strategy that separates the ``content'' of linguistic parameters from their representation. Algorithms based on it suffer from few of the search problems that have plagued other computational approaches to language acquisition. The theory has been tested on problems of learning vocabularies and grammars from unsegmented text and continuous speech, and mappings between sound and representations of meaning. It performs extremely well on various objective criteria, acquiring knowledge that causes it to assign almost exactly the same structure to utterances as humans do. This work has application to data compression, language modeling, speech recognition, machine translation, information retrieval, and other tasks that rely on either structural or stochastic descriptions of language.

  14. Nutrient Acquisition and Metabolism by Campylobacter jejuni

    Directory of Open Access Journals (Sweden)

    Martin eStahl


    Full Text Available The gastrointestinal pathogen Campylobacter jejuni is able to colonize numerous different hosts and compete against the gut microbiota. To do this, it must be able to efficiently acquire sufficient nutrients from its environment to support its survival and rapid growth in the intestine. However, despite almost 50 years of research, many aspects as to how C. jejuni accomplishes this feat remain poorly understood. C. jejuni lacks many of the common metabolic pathways necessary for the use of glucose, galactose, or other carbohydrates upon which most other microbes thrive. It does however make efficient use of citric acid cycle intermediates and various amino acids. C. jejuni readily uses the amino acids aspartate, glutamate, serine, and proline, with certain strains also possessing additional pathways allowing for the use of glutamine and asparagine. More recent work has revealed that some C. jejuni strains can metabolize the sugar L-fucose. This finding has upset years of dogma that C. jejuni is an asaccharolytic organism. C. jejuni also possesses diverse mechanisms for the acquisition of various transition metals that are required for metabolic activities. In particular, iron acquisition is critical for the formation of iron-sulphur complexes. C. jejuni is also unique in possessing both molybdate and tungsten cofactored proteins and thus has an unusual regulatory scheme for these metals. Together these various metabolic and acquisition pathways help C. jejuni to compete and thrive in wide variety of hosts and environments.

  15. Isothermal thermogravimetric data acquisition analysis system (United States)

    Cooper, Kenneth, Jr.


    The description of an Isothermal Thermogravimetric Analysis (TGA) Data Acquisition System is presented. The system consists of software and hardware to perform a wide variety of TGA experiments. The software is written in ANSI C using Borland's Turbo C++. The hardware consists of a 486/25 MHz machine with a Capital Equipment Corp. IEEE488 interface card. The interface is to a Hewlett Packard 3497A data acquisition system using two analog input cards and a digital actuator card. The system provides for 16 TGA rigs with weight and temperature measurements from each rig. Data collection is conducted in three phases. Acquisition is done at a rapid rate during initial startup, at a slower rate during extended data collection periods, and finally at a fast rate during shutdown. Parameters controlling the rate and duration of each phase are user programmable. Furnace control (raising and lowering) is also programmable. Provision is made for automatic restart in the event of power failure or other abnormal terminations. Initial trial runs were conducted to show system stability.

  16. Target Acquisition Methodology Enhancement (TAME) (United States)


    acquisition probability from COMINT, PCOM , against all communications type targets, is determined offline by a stochastic model for subsequent...of PN over all replications. F-4 f. Computes overall acquisition probability, PCOM , against all communications type targets as C: PCOM = (1. - PN...NNET where NNET denotes the number of nets which the target is in. F-6. TOTAL ACQUISITION PROBABILITY. With PNCj and PCOM computed as above, the

  17. Collection assessment and acquisitions budgets

    CERN Document Server

    Lee, Sul H


    This invaluable new book contains timely information about the assessment of academic library collections and the relationship of collection assessment to acquisition budgets. The rising cost of information significantly influences academic libraries'abilities to acquire the necessary materials for students and faculty, and public libraries'abilities to acquire material for their clientele. Collection Assessment and Acquisitions Budgets examines different aspects of the relationship between the assessment of academic library collections and the management of library acquisition budgets. Librar

  18. Dependence of bacterial chemotaxis on gradient shape and adaptation rate.

    Directory of Open Access Journals (Sweden)

    Nikita Vladimirov


    Full Text Available Simulation of cellular behavior on multiple scales requires models that are sufficiently detailed to capture central intracellular processes but at the same time enable the simulation of entire cell populations in a computationally cheap way. In this paper we present RapidCell, a hybrid model of chemotactic Escherichia coli that combines the Monod-Wyman-Changeux signal processing by mixed chemoreceptor clusters, the adaptation dynamics described by ordinary differential equations, and a detailed model of cell tumbling. Our model dramatically reduces computational costs and allows the highly efficient simulation of E. coli chemotaxis. We use the model to investigate chemotaxis in different gradients, and suggest a new, constant-activity type of gradient to systematically study chemotactic behavior of virtual bacteria. Using the unique properties of this gradient, we show that optimal chemotaxis is observed in a narrow range of CheA kinase activity, where concentration of the response regulator CheY-P falls into the operating range of flagellar motors. Our simulations also confirm that the CheB phosphorylation feedback improves chemotactic efficiency by shifting the average CheY-P concentration to fit the motor operating range. Our results suggest that in liquid media the variability in adaptation times among cells may be evolutionary favorable to ensure coexistence of subpopulations that will be optimally tactic in different gradients. However, in a porous medium (agar such variability appears to be less important, because agar structure poses mainly negative selection against subpopulations with low levels of adaptation enzymes. RapidCell is available from the authors upon request.

  19. Uncertainty-Based Approach for Dynamic Aerodynamic Data Acquisition and Analysis (United States)

    Heim, Eugene H. D.; Bandon, Jay M.


    Development of improved modeling methods to provide increased fidelity of flight predictions for aircraft motions during flight in flow regimes with large nonlinearities requires improvements in test techniques for measuring and characterizing wind tunnel data. This paper presents a method for providing a measure of data integrity for static and forced oscillation test techniques. Data integrity is particularly important when attempting to accurately model and predict flight of today s high performance aircraft which are operating in expanded flight envelopes, often maneuvering at high angular rates at high angles-of-attack, even above maximum lift. Current aerodynamic models are inadequate in predicting flight characteristics in the expanded envelope, such as rapid aircraft departures and other unusual motions. Present wind tunnel test methods do not factor changes of flow physics into data acquisition schemes, so in many cases data are obtained over more iterations than required, or insufficient data may be obtained to determine a valid estimate with statistical significance. Additionally, forced oscillation test techniques, one of the primary tools used to develop dynamic models, do not currently provide estimates of the uncertainty of the results during an oscillation cycle. A method to optimize the required number of forced oscillation cycles based on decay of uncertainty gradients and balance tolerances is also presented.

  20. Data Acquisition Systems course

    CERN Multimedia

    CERN. Geneva HR-RFA


    We will review the main physics and operational requirements on the Trigger and Data Acquisition (DAQ) systems of the LHC experiments. A description of the architecture of the various systems, the motivation of each alternative and the conceptual design of each filtering stage will be discussed. We will then turn to a description of the major elements of the three distinct sub-systems, namely the Level-1 trigger, the DAQ with its event-building and overall control and monitor, and finally the High-Level trigger system and the online processor farms. The thrust of the two lectures will be to provide a "broad brush" picture of the functionality of these systems.

  1. Theories of language acquisition. (United States)

    Vetter, H J; Howell, R W


    Prior to the advent of generative grammar, theoretical approaches to language development relied heavily upon the concepts ofdifferential reinforcement andimitation. Current studies of linguistic acquisition are largely dominated by the hypothesis that the child constructs his language on the basis of a primitive grammar which gradually evolves into a more complex grammar. This approach presupposes that the investigator does not impose his own grammatical rules on the utterances of the child; that the sound system of the child and the rules he employs to form sentences are to be described in their own terms, independently of the model provided by the adult linguistic community; and that there is a series of steps or stages through which the child passes on his way toward mastery of the adult grammar in his linguistic environment. This paper attempts to trace the development of human vocalization through prelinguistic stages to the development of what can be clearly recognized as language behavior, and then progresses to transitional phases in which the language of the child begins to approximate that of the adult model. In the view of the authors, the most challenging problems which confront theories of linguistic acquisition arise in seeking to account for structure of sound sequences, in the rules that enable the speaker to go from meaning to sound and which enable the listener to go from sound to meaning. The principal area of concern for the investigator, according to the authors, is the discovery of those rules at various stages of the learning process. The paper concludes with a return to the question of what constitutes an adequate theory of language ontogenesis. It is suggested that such a theory will have to be keyed to theories of cognitive development and will have to include and go beyond a theory which accounts for adult language competence and performance, since these represent only the terminal stage of linguistic ontogenesis.

  2. Electronic Flash In Data Acquisition (United States)

    Miller, C. E.


    Photographic acquisition of data often may be simplified, or the data quality improved upon by employing electronic flash sources with traditional equipment or techniques. The relatively short flash duration compared to movie camera shutters, or to the long integration time of video camera provides improved spatial resolution through blur reduction, particularly important as image movement becomes a significant fraction of film format dimension. Greater accuracy typically is achieved in velocity and acceleration determinations by using a stroboscopic light source rather than a movie camera frame-rate control as a time standard. Electrical efficiency often is an important advantage of electronic flash sources since almost any necessary light level for exposure may be produced, yet the source typically is "off" most of the time. Various synchronization techniques greatly expand the precise control of exposure. Biomechanical and sports equipment studies may involve velocities up to 200 feet-per-second, and often will have associated very rapid actions of interest. The need for brief exposures increases H.s one "ZOOMS in on the action." In golf, for example, the swing may be examined using 100 microsecond (Us) flashes at rates of 60 or 120 flashes-per-second (FPS). Accurate determination of linear and rotational velocity of the ball requires 10 Us flashes at 500-1,000 FPS, while sub-Us flashes at 20,000-50,000 FPS are required to resolve the interaction of the ball and the club, head. Some seldom. used techniques involving streak photography are described, with enhanced results obtained by combining strobe with the usual continuous light source. The combination of strobe and a fast electro-mechanical shutter is considered for Us photography under daylight conditions.

  3. Superconductors in a temperature gradient

    CERN Document Server

    Huebener, Rudolf Peter


    In the mixed state of a type II superconductor quasiparticles and magnetic flux quanta respond to a temperature gradient by thermal diffusion, in this way generating the Seebeck and Nernst effects, respectively. Our understanding of the Seebeck effect originates from an extension of the two-fluid counterflow concept, originally introduced by Ginzburg, to the situation where vortices (with a normal core) are imbedded in the superconducting phase. This mechanism results in an intimate connection between the Seebeck coefficient and the electric resistivity due to vortex motion. In all thermal diffusion processes it is the transport entropy of the diffusing species that determines the driving force, and the physics of this quantity is illustrated. Our discussion of the experimental side concentrates on the recent work performed with the cuprate superconductors. The characteristic broadening of the resistive transition in the mixed state, found in these materials due to their high anisotropy and the peculiar vorte...

  4. Combined Spin-And Gradient-Echo Perfusion-Weighted Imaging (United States)

    Schmiedeskamp, Heiko; Straka, Matus; Newbould, Rexford D.; Zaharchuk, Greg; Andre, Jalal B.; Olivot, Jean-Marc; Moseley, Michael E.; Albers, Gregory W.; Bammer, Roland


    In this study, a spin- and gradient-echo echo-planar imaging (SAGE EPI) MRI pulse sequence is presented that allows simultaneous measurements of gradient-echo and spin-echo dynamic susceptibility-contrast perfusion-weighted imaging (DSC-PWI) data. Following signal excitation, five EPI readout trains were acquired using SAGE EPI, all of them with echo times of less than 100 ms. Contrast agent concentrations in brain tissue were determined based on absolute R2* and R2 estimates rather than relative changes in the signals of individual echo trains, producing T1-independent DSC-PWI data. Moreover, this acquisition technique enabled vessel size imaging through the simultaneous quantification of R2* and R2, without an increase in acquisition time. In this work, the concepts of the SAGE EPI pulse sequence and results in stroke and tumor imaging are presented. Overall, SAGE EPI combined the advantages of higher sensitivity of gradient-echo DSC-PWI acquisitions to the contrast agent passage with the better selectivity of spin-echo DSC-PWI measurements to the microvasculature. PMID:22114040

  5. Biological Constraints on Literacy Acquisition. (United States)

    Cossu, Giuseppe


    Investigates some of the biological constraints that shape the process of literacy acquisition. Explores the possibility of isolating processing components of reading which correspond to computational units of equivalent size in the neural architecture. Suggests that the process of literacy acquisition is largely constrained by a specific…

  6. Foreign Acquisition, Wages and Productivity

    DEFF Research Database (Denmark)

    Bandick, Roger


    This paper studies the effect of foreign acquisition on wages and total factor productivity (TFP) in the years following a takeover by using unique detailed firm-level data for Sweden for the period 1993-2002. The paper takes particular account of the potential endogeneity of the acquisition...

  7. Foreign Acquisition, Wages and Productivity

    DEFF Research Database (Denmark)

    Bandick, Roger

    This paper studies the effect of foreign acquisition on wages and total factor productivity (TFP) in the years following a takeover by using unique detailed firm-level data for Sweden for the period 1993-2002. The paper takes particular account of the potential endogeneity of the acquisition...

  8. Defense Acquisition Performance Assessment Report (United States)


    Development – “Acquisition Reform and Interoperability” BARTLeTT, ROsALiND , Analyst, Office of the Deputy Assistant Secretary of the Navy for Acquisition...Managers Performance Review” FRANKLiN , CHARLes, Vice-President, Raytheon Company Evaluation Team – “Corporate Perspective” FRANKLiN , RuTH W., Director

  9. Community and ecosystem responses to elevational gradients

    DEFF Research Database (Denmark)

    Sundqvist, Maja K.; Sanders, Nate; Wardle, David A.


    Community structure and ecosystem processes often vary along elevational gradients. Their responses to elevation are commonly driven by changes in temperature, and many community- and ecosystem-level variables therefore frequently respond similarly to elevation across contrasting gradients. There...... will provide powerful information that can improve predictions of climate change impacts within and across ecosystems.......Community structure and ecosystem processes often vary along elevational gradients. Their responses to elevation are commonly driven by changes in temperature, and many community- and ecosystem-level variables therefore frequently respond similarly to elevation across contrasting gradients...... elevational gradients for understanding community and ecosystem responses to global climate change at much larger spatial and temporal scales than is possible through conventional ecological experiments. However, future studies that integrate elevational gradient approaches with experimental manipulations...

  10. Color and population gradients in globular clusters (United States)

    Djorgovski, S.; Piotto, G.; Mallen-Ornelas, G.


    We present preliminary results from a survey for color and population gradients in globular cluster cores. Color gradients, in the sense of becoming bluer inwards, are always found in post-core-collapse clusters. They seem to be caused by the demise of red giants, and possibly an increased number of blue stragglers. This may be a consequence of stellar interactions during and after the core collapse. No gradients are seen in clusters with King-model morphology.

  11. Ant colony optimization and stochastic gradient descent. (United States)

    Meuleau, Nicolas; Dorigo, Marco


    In this article, we study the relationship between the two techniques known as ant colony optimization (ACO) and stochastic gradient descent. More precisely, we show that some empirical ACO algorithms approximate stochastic gradient descent in the space of pheromones, and we propose an implementation of stochastic gradient descent that belongs to the family of ACO algorithms. We then use this insight to explore the mutual contributions of the two techniques.

  12. Testing the limits of gradient sensing.

    Directory of Open Access Journals (Sweden)

    Vinal Lakhani


    Full Text Available The ability to detect a chemical gradient is fundamental to many cellular processes. In multicellular organisms gradient sensing plays an important role in many physiological processes such as wound healing and development. Unicellular organisms use gradient sensing to move (chemotaxis or grow (chemotropism towards a favorable environment. Some cells are capable of detecting extremely shallow gradients, even in the presence of significant molecular-level noise. For example, yeast have been reported to detect pheromone gradients as shallow as 0.1 nM/μm. Noise reduction mechanisms, such as time-averaging and the internalization of pheromone molecules, have been proposed to explain how yeast cells filter fluctuations and detect shallow gradients. Here, we use a Particle-Based Reaction-Diffusion model of ligand-receptor dynamics to test the effectiveness of these mechanisms and to determine the limits of gradient sensing. In particular, we develop novel simulation methods for establishing chemical gradients that not only allow us to study gradient sensing under steady-state conditions, but also take into account transient effects as the gradient forms. Based on reported measurements of reaction rates, our results indicate neither time-averaging nor receptor endocytosis significantly improves the cell's accuracy in detecting gradients over time scales associated with the initiation of polarized growth. Additionally, our results demonstrate the physical barrier of the cell membrane sharpens chemical gradients across the cell. While our studies are motivated by the mating response of yeast, we believe our results and simulation methods will find applications in many different contexts.

  13. Developing Acquisition IS Integration Capabilities

    DEFF Research Database (Denmark)

    Wynne, Peter J.


    An under researched, yet critical challenge of Mergers and Acquisitions (M&A), is what to do with the two organisations’ information systems (IS) post-acquisition. Commonly referred to as acquisition IS integration, existing theory suggests that to integrate the information systems successfully......, an acquiring company must leverage two high level capabilities: diagnosis and integration execution. Through a case study, this paper identifies how a novice acquirer develops these capabilities in anticipation of an acquisition by examining its use of learning processes. The study finds the novice acquirer...... applies trial and error, experimental, and vicarious learning processes, while actively avoiding improvisational learning. The results of the study contribute to the acquisition IS integration literature specifically by exploring it from a new perspective: the learning processes used by novice acquirers...

  14. A simplified spin and gradient echo approach for brain tumor perfusion imaging. (United States)

    Stokes, Ashley M; Quarles, C Chad


    In this study, we propose a simplified acquisition and analysis approach for spin and gradient echo (SAGE)-based dynamic susceptibility-contrast MRI (DSC-MRI) data that is free of contrast agent T1 leakage effects. A five-echo SAGE sequence was used to acquire DSC-MRI data in rat C6 tumors (n = 7). Nonlinear fitting of all echoes was performed to obtain T1-insensitive ΔR2* and ΔR2 time series. The simplified approach, which includes two gradient echoes and one spin echo, was also used to analytically compute T1-insensitive ΔR2* using the two gradient echoes and ΔR2 using all three echoes. The blood flow, blood volume, and vessel size values derived from each method were compared. In all cases, the five-echo and simplified SAGE ΔR2* and ΔR2 were in excellent agreement and demonstrated significant T1 leakage correction compared with the uncorrected single-echo data. The derived hemodynamic parameters for blood volume, blood flow, and vessel size were not significantly different between the two methods. The proposed simplified SAGE technique enables the acquisition of gradient and spin echo DSC-MRI data corrected for T1 leakage effects yields parameters that are in agreement with the five-echo SAGE approach and does not require nonlinear fitting to extract ΔR2* and ΔR2 time series. © 2015 Wiley Periodicals, Inc.

  15. A Simplified Spin and Gradient Echo (SAGE) Approach for Brain Tumor Perfusion Imaging (United States)

    Stokes, Ashley M.; Quarles, C. Chad


    Purpose A simplified acquisition and analysis approach for spin- and gradient-echo (SAGE) based DSC-MRI data that is free of contrast agent T1 leakage effects is proposed. Methods A five-echo SAGE sequence was used to acquire DSC-MRI data in rat C6 tumors (n=7). Non-linear fitting of all echoes was performed to obtain T1-insensitive ΔR2* and ΔR2 time series. The simplified approach, which includes two gradient echoes and one spin echo, was also used to analytically compute T1-insensitive ΔR2*, using the two gradient echoes, and ΔR2, using all three echoes. The blood flow, blood volume and vessel size values derived from each method were compared. Results In all cases, the five-echo and simplified SAGE ΔR2* and ΔR2 were in excellent agreement and demonstrated significant T1-leakage correction compared to the uncorrected single-echo data. The derived hemodynamic parameters for blood volume, blood flow and vessel size were not significantly different between the two methods. Conclusions The proposed simplified SAGE technique enables the acquisition of gradient and spin echo DSC-MRI data corrected for T1 leakage effects, yields parameters that are in agreement with the five echo SAGE, and does not require non-linear fitting to extract ΔR2* and ΔR2 time series. PMID:25753958

  16. 48 CFR 873.105 - Acquisition planning. (United States)


    ... 48 Federal Acquisition Regulations System 5 2010-10-01 2010-10-01 false Acquisition planning. 873.105 Section 873.105 Federal Acquisition Regulations System DEPARTMENT OF VETERANS AFFAIRS DEPARTMENT... planning. (a) Acquisition planning is an indispensable component of the total acquisition process. (b) For...

  17. 48 CFR 234.004 - Acquisition strategy. (United States)


    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Acquisition strategy. 234..., DEPARTMENT OF DEFENSE SPECIAL CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION 234.004 Acquisition strategy. (1) See 209.570 for policy applicable to acquisition strategies that consider the use of lead system...

  18. 48 CFR 34.004 - Acquisition strategy. (United States)


    ... 48 Federal Acquisition Regulations System 1 2010-10-01 2010-10-01 false Acquisition strategy. 34... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 34.004 Acquisition strategy. The program manager, as specified in agency procedures, shall develop an acquisition strategy tailored to the particular...

  19. 48 CFR 3034.004 - Acquisition strategy. (United States)


    ... 48 Federal Acquisition Regulations System 7 2010-10-01 2010-10-01 false Acquisition strategy. 3034.004 Section 3034.004 Federal Acquisition Regulations System DEPARTMENT OF HOMELAND SECURITY, HOMELAND... Acquisition strategy. See (HSAR) 48 CFR 3009.570 for policy applicable to acquisition strategies that consider...


    CERN Multimedia

    Gerry Bauer

    The CMS Storage Manager System The tail-end of the CMS Data Acquisition System is the Storage Manger (SM), which collects output from the HLT and stages the data at Cessy for transfer to its ultimate home in the Tier-0 center. A SM system has been used by CMS for several years with the steadily evolving software within the XDAQ framework, but until relatively recently, only with provisional hardware. The SM is well known to much of the collaboration through the ‘MiniDAQ’ system, which served as the central DAQ system in 2007, and lives on in 2008 for dedicated sub-detector commissioning. Since March of 2008 a first phase of the final hardware was commissioned and used in CMS Global Runs. The system originally planned for 2008 aimed at recording ~1MB events at a few hundred Hz. The building blocks to achieve this are based on Nexsan's SATABeast storage array - a device  housing up to 40 disks of 1TB each, and possessing two controllers each capable of almost 200 MB/sec throughput....

  1. Acquisition of Oocyte Polarity. (United States)

    Clapp, Mara; Marlow, Florence L


    Acquisition of oocyte polarity involves complex translocation and aggregation of intracellular organelles, RNAs, and proteins, along with strict posttranscriptional regulation. While much is still unknown regarding the formation of the animal-vegetal axis, an early marker of polarity, animal models have contributed to our understanding of these early processes controlling normal oogenesis and embryo development. In recent years, it has become clear that proteins with self-assembling properties are involved in assembling discrete subcellular compartments or domains underlying subcellular asymmetries in the early mitotic and meiotic cells of the female germline. These include asymmetries in duplication of the centrioles and formation of centrosomes and assembly of the organelle and RNA-rich Balbiani body, which plays a critical role in oocyte polarity. Notably, at specific stages of germline development, these transient structures in oocytes are temporally coincident and align with asymmetries in the position and arrangement of nuclear components, such as the nuclear pore and the chromosomal bouquet and the centrioles and cytoskeleton in the cytoplasm. Formation of these critical, transient structures and arrangements involves microtubule pathways, intrinsically disordered proteins (proteins with domains that tend to be fluid or lack a rigid ordered three-dimensional structure ranging from random coils, globular domains, to completely unstructured proteins), and translational repressors and activators. This review aims to examine recent literature and key players in oocyte polarity.

  2. Trigger and data acquisition

    CERN Multimedia

    CERN. Geneva; Gaspar, C


    Past LEP experiments generate data at 0.5 MByte/s from particle detectors with over a quarter of a million readout channels. The process of reading out the electronic channels, treating them, and storing the date produced by each collision for further analysis by the physicists is called "Data Acquisition". Not all beam crossings produce interesting physics "events", picking the interesting ones is the task of the "Trigger" system. In order to make sure that the data is collected in good conditions the experiment's operation has to be constantly verified. In all, at LEP experiments over 100 000 parameters were monitored, controlled, and synchronized by the "Monotoring and control" system. In the future, LHC experiments will produce as much data in a single day as a LEP detector did in a full year's running with a raw data rate of 10 - 100 MBytes/s and will have to cope with some 800 million proton-proton collisions a second of these collisions only one in 100 million million is interesting for new particle se...

  3. Rapid Statistical Learning Supporting Word Extraction From Continuous Speech. (United States)

    Batterink, Laura J


    The identification of words in continuous speech, known as speech segmentation, is a critical early step in language acquisition. This process is partially supported by statistical learning, the ability to extract patterns from the environment. Given that speech segmentation represents a potential bottleneck for language acquisition, patterns in speech may be extracted very rapidly, without extensive exposure. This hypothesis was examined by exposing participants to continuous speech streams composed of novel repeating nonsense words. Learning was measured on-line using a reaction time task. After merely one exposure to an embedded novel word, learners demonstrated significant learning effects, as revealed by faster responses to predictable than to unpredictable syllables. These results demonstrate that learners gained sensitivity to the statistical structure of unfamiliar speech on a very rapid timescale. This ability may play an essential role in early stages of language acquisition, allowing learners to rapidly identify word candidates and "break in" to an unfamiliar language.

  4. Microfluidic Concentric Gradient Generator Design for High-Throughput Cell-Based Studies. (United States)

    Ezra Tsur, Elishai; Zimerman, Michal; Maor, Idan; Elrich, Avner; Nahmias, Yaakov


    Gradients of diffusible signaling molecules play important role in various processes, ranging from cell differentiation to toxicological evaluation. Microfluidic technology provides an accurate control of tempospatial conditions. However, current microfluidic platforms are not designed to handle multiple gradients and cell populations simultaneously. Here, we demonstrate a rapidly adaptable microfluidic design able to expose multiple cell populations to an array of chemical gradients. Our design is based on pressure-equilibrated concentric channels and a pressure-dissipating control layer, facilitating the seeding of multiple cell populations in a single device. The design was numerically evaluated and experimentally validated. The device consists of 8 radiating stimuli channels and 12 circular cell culture channels, creating an array of 96 different continuous gradients that can be simultaneously monitored over time.

  5. Canonical trivialization of gravitational gradients (United States)

    Niedermaier, Max


    A one-parameter family of canonical transformations is constructed that reduces the Hamiltonian form of the Einstein-Hilbert action to its strong coupling limit where dynamical spatial gradients are absent. The parameter can alternatively be viewed as the overall scale of the spatial metric or as a fractional inverse power of Newton’s constant. The generating function of the canonical transformation is constructed iteratively as a powerseries in the parameter to all orders. The algorithm draws on Lie-Deprit transformation theory and defines a ‘trivialization map’ with several bonus properties: (i) Trivialization of the Hamiltonian constraint implies that of the action while the diffeomorphism constraint is automatically co-transformed. (ii) Only a set of ordinary differential equations needs to be solved to drive the iteration via a homological equation where no gauge fixing is required. (iii) In contrast to (the classical limit of) a Lagrangian trivialization map the algorithm also produces series solutions of the field equations. (iv) In the strong coupling theory temporal gauge variations are abelian, nevertheless the map intertwines with the respective gauge symmetries on the action, the field equations, and their solutions.

  6. Ultrafast 3D spin-echo acquisition improves Gadolinium-enhanced MRI signal contrast enhancement (United States)

    Han, S. H.; Cho, F. H.; Song, Y. K.; Paulsen, J.; Song, Y. Q.; Kim, Y. R.; Kim, J. K.; Cho, G.; Cho, H.


    Long scan times of 3D volumetric MR acquisitions usually necessitate ultrafast in vivo gradient-echo acquisitions, which are intrinsically susceptible to magnetic field inhomogeneities. This is especially problematic for contrast-enhanced (CE)-MRI applications, where non-negligible T2* effect of contrast agent deteriorates the positive signal contrast and limits the available range of MR acquisition parameters and injection doses. To overcome these shortcomings without degrading temporal resolution, ultrafast spin-echo acquisitions were implemented. Specifically, a multiplicative acceleration factor from multiple spin echoes (×32) and compressed sensing (CS) sampling (×8) allowed highly-accelerated 3D Multiple-Modulation-Multiple-Echo (MMME) acquisition. At the same time, the CE-MRI of kidney with Gd-DOTA showed significantly improved signal enhancement for CS-MMME acquisitions (×7) over that of corresponding FLASH acquisitions (×2). Increased positive contrast enhancement and highly accelerated acquisition of extended volume with reduced RF irradiations will be beneficial for oncological and nephrological applications, in which the accurate in vivo 3D quantification of contrast agent concentration is necessary with high temporal resolution. PMID:24863102

  7. Ultrashort echo time imaging with acquisition trajectory mapping for correction of gradient imperfections

    Czech Academy of Sciences Publication Activity Database

    Latta, P.; Starčuk jr., Zenon; Gruwel, M. L. H.; Tománek, B.


    Roč. 28, S1 (2015), S102 ISSN 0968-5243. [ESMRMB 2015. Annual Scientific Meeting /32./. 01.09.2015-03.09.2015, Edinburgh] R&D Projects: GA ČR(CZ) GA15-12607S Institutional support: RVO:68081731 Keywords : UTE MRI * radial sampling * image reconstructio Subject RIV: FS - Medical Facilities ; Equipment

  8. Data acquisition techniques using PC

    CERN Document Server

    Austerlitz, Howard


    Data Acquisition Techniques Using Personal Computers contains all the information required by a technical professional (engineer, scientist, technician) to implement a PC-based acquisition system. Including both basic tutorial information as well as some advanced topics, this work is suitable as a reference book for engineers or as a supplemental text for engineering students. It gives the reader enough understanding of the topics to implement a data acquisition system based on commercial products. A reader can alternatively learn how to custom build hardware or write his or her own software.

  9. The Acquisition Experiences of Kazoil

    DEFF Research Database (Denmark)

    Minbaeva, Dana; Muratbekova-Touron, Maral


    This case describes two diverging post-acquisition experiences of KazOil, an oil drilling company in Kazakhstan, in the years after the dissolution of the Soviet Union. When the company was bought by the Canadian corporation Hydrocarbons Ltd in 1996, exposed to new human resource strategies...... among students that cultural distance is not the main determinant for the success of social integration mechanisms in post-acquisition situations. On the contrary, the relationship between integration instrument and integration success is also governed by contextual factors such as the attractiveness...... of the acquisition target or state of development of HRM in the target country....

  10. Bootstrapping language acquisition. (United States)

    Abend, Omri; Kwiatkowski, Tom; Smith, Nathaniel J; Goldwater, Sharon; Steedman, Mark


    The semantic bootstrapping hypothesis proposes that children acquire their native language through exposure to sentences of the language paired with structured representations of their meaning, whose component substructures can be associated with words and syntactic structures used to express these concepts. The child's task is then to learn a language-specific grammar and lexicon based on (probably contextually ambiguous, possibly somewhat noisy) pairs of sentences and their meaning representations (logical forms). Starting from these assumptions, we develop a Bayesian probabilistic account of semantically bootstrapped first-language acquisition in the child, based on techniques from computational parsing and interpretation of unrestricted text. Our learner jointly models (a) word learning: the mapping between components of the given sentential meaning and lexical words (or phrases) of the language, and (b) syntax learning: the projection of lexical elements onto sentences by universal construction-free syntactic rules. Using an incremental learning algorithm, we apply the model to a dataset of real syntactically complex child-directed utterances and (pseudo) logical forms, the latter including contextually plausible but irrelevant distractors. Taking the Eve section of the CHILDES corpus as input, the model simulates several well-documented phenomena from the developmental literature. In particular, the model exhibits syntactic bootstrapping effects (in which previously learned constructions facilitate the learning of novel words), sudden jumps in learning without explicit parameter setting, acceleration of word-learning (the "vocabulary spurt"), an initial bias favoring the learning of nouns over verbs, and one-shot learning of words and their meanings. The learner thus demonstrates how statistical learning over structured representations can provide a unified account for these seemingly disparate phenomena. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. Regulation of leaf traits in canopy gradients.

    NARCIS (Netherlands)

    Pons, T.L.|info:eu-repo/dai/nl/069365822


    The gradient of leaf traits in a canopy from sunlit upper regions to shaded lower ones is regulated in response to the density of its leaf area. The gradients of environmental factors act as signals for the regulation. The result is improved resource use efficiency for carbon gain at the whole plant

  12. Preconditioning the modified conjugate gradient method ...

    African Journals Online (AJOL)

    In this paper, the convergence analysis of the conventional conjugate Gradient method was reviewed. And the convergence analysis of the modified conjugate Gradient method was analysed with our extension on preconditioning the algorithm. Convergence of the algorithm is a function of the condition number of M-1A.

  13. Gradient High Performance Liquid Chromatography Method ...

    African Journals Online (AJOL)

    Purpose: To develop a gradient high performance liquid chromatography (HPLC) method for the simultaneous determination of phenylephrine (PHE) and ibuprofen (IBU) in solid dosage form. Methods: HPLC determination was carried out on an Agilent XDB C-18 column (4.6 x 150mm, 5 μ particle size) with a gradient ...

  14. An Inexpensive Digital Gradient Controller for HPLC. (United States)

    Brady, James E.; Carr, Peter W.


    Use of gradient elution techniques in high performance liquid chromatography (HPLC) is often essential for direct separation of complex mixtures. Since most commercial controllers have features that are of marginal value for instructional purposes, a low-cost controller capable of illustrating essential features of gradient elution was developed.…

  15. Newton's method in the context of gradients

    Directory of Open Access Journals (Sweden)

    John W. Neuberger


    Full Text Available This paper gives a common theoretical treatment for gradient and Newton type methods for general classes of problems. First, for Euler-Lagrange equations Newton's method is characterized as an (asymptotically optimal variable steepest descent method. Second, Sobolev gradient type minimization is developed for general problems using a continuous Newton method which takes into account a "boundary condition" operator.

  16. Patterns of macromycete community assemblage along an elevation gradient: options for fungal gradient and metacommunity analyse (United States)

    Marko Gómez-Hernández; Guadalupe Williams-Linera; Roger Guevara; D. Jean Lodge


    Gradient analysis is rarely used in studies of fungal communities. Data on macromycetes from eight sites along an elevation gradient in central Veracruz, Mexico, were used to demonstrate methods for gradient analysis that can be applied to studies of communities of fungi. Selected sites from 100 to 3,500 m altitude represent tropical dry forest, tropical montane cloud...

  17. Delayed motor skill acquisition in kindergarten children with language impairment. (United States)

    Adi-Japha, Esther; Strulovich-Schwartz, Orli; Julius, Mona


    The acquisition and consolidation of a new grapho-motor symbol into long-term memory was studied in 5-year-old children with language impairment (LI) and peers matched for age and visual-motor integration skills. The children practiced the production of a new symbol and were tested 24h and two weeks post-practice day. Differences in performance speed emerged between the groups: children with LI showed a later onset of rapid learning in the practice phase, and only the comparison group exhibited delayed, consolidation, gains 24h post-training. At two weeks post-training, children with LI improved, closing the gap in performance speed. Speed-accuracy trade-off was characteristic of speed improvements in LI. These results indicate atypical and delayed acquisition in children with LI, and support the view that deficient skill acquisition in LI goes beyond the language system. Copyright © 2011 Elsevier Ltd. All rights reserved.

  18. Approximate error conjugation gradient minimization methods (United States)

    Kallman, Jeffrey S


    In one embodiment, a method includes selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, calculating an approximate error using the subset of rays, and calculating a minimum in a conjugate gradient direction based on the approximate error. In another embodiment, a system includes a processor for executing logic, logic for selecting a subset of rays from a set of all rays to use in an error calculation for a constrained conjugate gradient minimization problem, logic for calculating an approximate error using the subset of rays, and logic for calculating a minimum in a conjugate gradient direction based on the approximate error. In other embodiments, computer program products, methods, and systems are described capable of using approximate error in constrained conjugate gradient minimization problems.

  19. Dual fuel gradients in uranium silicide plates

    Energy Technology Data Exchange (ETDEWEB)

    Pace, B.W. [Babock and Wilcox, Lynchburg, VA (United States)


    Babcock & Wilcox has been able to achieve dual gradient plates with good repeatability in small lots of U{sub 3}Si{sub 2} plates. Improvements in homogeneity and other processing parameters and techniques have allowed the development of contoured fuel within the cladding. The most difficult obstacles to overcome have been the ability to evaluate the bidirectional fuel loadings in comparison to the perfect loading model and the different methods of instilling the gradients in the early compact stage. The overriding conclusion is that to control the contour of the fuel, a known relationship between the compact, the frames and final core gradient must exist. Therefore, further development in the creation and control of dual gradients in fuel plates will involve arriving at a plausible gradient requirement and building the correct model between the compact configuration and the final contoured loading requirements.

  20. Protein gradient films of fibroin and gelatine. (United States)

    Claussen, Kai U; Lintz, Eileen S; Giesa, Reiner; Schmidt, Hans-Werner; Scheibel, Thomas


    Gradients are a natural design principle in biological systems that are used to diminish stress concentration where materials of differing mechanical properties connect. An interesting example of a natural gradient material is byssus, which anchors mussels to rocks and other hard substrata. Building upon previous work with synthetic polymers and inspired by byssal threads, protein gradient films are cast using glycerine-plasticized gelatine and fibroin exhibiting a highly reproducible and smooth mechanical gradient, which encompasses a large range of modulus from 160 to 550 MPa. The reproducible production of biocompatible gradient films represents a first step towards medical applications. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Integral analysis of boundary layer flows with pressure gradient (United States)

    Wei, Tie; Maciel, Yvan; Klewicki, Joseph


    This Rapid Communication investigates boundary layer flows with a pressure gradient using a similarity/integral analysis of the continuity equation and momentum equation in the streamwise direction. The analysis yields useful analytical relations for Ve, the mean wall-normal velocity at the edge of the boundary layer, and for the skin friction coefficient Cf in terms of the boundary layer parameters and in particular βRC, the Rotta-Clauser pressure gradient parameter. The analytical results are compared with experimental and numerical data and are found to be valid. One of the main findings is that for large positive βRC (an important effect of an adverse pressure gradient), the friction coefficient is closely related to βRC as Cf∝1 /βRC , because δ /δ1,δ1/δ2=H , and d δ /d x become approximately constant. Here, δ is the boundary layer thickness, δ1 is the displacement thickness, δ2 is the momentum thickness, and H is the shape factor. Another finding is that the mean wall-normal velocity at the edge of the boundary layer is related to other flow variables as UeVe/uτ2=H +(1 +δ /δ1+H ) βRC , where Ue is the streamwise velocity at the edge of the boundary layer. At zero pressure gradient, this relation reduces to U∞V∞/uτ2=H , as recently derived by Wei and Klewicki [Phys. Rev. Fluids 1, 082401 (2016), 10.1103/PhysRevFluids.1.082401].

  2. Schizophrenia and second language acquisition. (United States)

    Bersudsky, Yuly; Fine, Jonathan; Gorjaltsan, Igor; Chen, Osnat; Walters, Joel


    Language acquisition involves brain processes that can be affected by lesions or dysfunctions in several brain systems and second language acquisition may depend on different brain substrates than first language acquisition in childhood. A total of 16 Russian immigrants to Israel, 8 diagnosed schizophrenics and 8 healthy immigrants, were compared. The primary data for this study were collected via sociolinguistic interviews. The two groups use language and learn language in very much the same way. Only exophoric reference and blocking revealed meaningful differences between the schizophrenics and healthy counterparts. This does not mean of course that schizophrenia does not induce language abnormalities. Our study focuses on those aspects of language that are typically difficult to acquire in second language acquisition. Despite the cognitive compromises in schizophrenia and the manifest atypicalities in language of speakers with schizophrenia, the process of acquiring a second language seems relatively unaffected by schizophrenia.

  3. Platform attitude data acquisition system

    Digital Repository Service at National Institute of Oceanography (India)

    Afzulpurkar, S.

    A system for automatic acquisition of underwater platform attitude data has been designed, developed and tested in the laboratory. This is a micro controller based system interfacing dual axis inclinometer, high-resolution digital compass...

  4. Portable Data Acquisition System Project (United States)

    National Aeronautics and Space Administration — Armstrong researchers have developed a portable data acquisition system (PDAT) that can be easily transported and set up at remote locations to display and archive...

  5. Challenges in Mergers and Acquisitions


    Phyllis J. Rivera


    Since the advent of globalization and tough competitive market, there has been a drastic shift in the global business environment towards the acquisitions and mergers. The consolidation and acquisitions are undertaken for the purpose of increasing capabilities and gaining larger market share, but many high profile mergers become unsuccessful to meet the organizational objectives because of inadequate role of Human resources and the issues revolving in it (Love, 2000).The mergers and acquisiti...

  6. Prerequisites for acquisition of inheritance


    Večeřová, Marta


    Title: Prerequisites for Acquisition of Inheritance Keywords: deceased, inheritance, heir Type of paper: Thesis Author: Mgr. Daniela Bendová Supervisor: prof. JUDr. Jan Dvořák, CSc. Faculty of Law of Charles University Department of Civil Law The thesis addresses rudimentary prerequisites for acquisition of inheritance in the Czech Republic. These prerequisites include death of a person, that is necessary for application of inheritance rights, existence of inheritance, in particular ownership...

  7. Mergers and acquisitions for the radiologist. (United States)

    Fleishon, Howard B


    In 2006 and the first half of 2007, the rapid pace of global activity contributed to the popularity of mergers and acquisitions (M&A). In fact, the medical imaging industry has a significant history in M&A as well. Along with the expectation of continued growth in medical imaging utilization and other industry trends, radiologists may become more involved in M&A transactions. There is little in the radiology literature dealing with the logistics and pitfalls of M&A. This article is an introduction for radiologists who might consider buying or selling their practices or merging with strategic partners. Although there are significant differences in the approaches of buy or sell situations compared with mergers, they do share several concepts that are outlined. One key to success in M&A transactions is the "process" or approach, which is described with some practical guidelines. Some basic terms and suggestions are also presented for reference.

  8. Correction of gradient echo images for first and second order macroscopic signal dephasing using phase derivative mapping. (United States)

    de Leeuw, H; Bakker, C J G


    Gradient echo techniques are often hampered by signal dephasing due to macroscopic phase perturbations because of system imperfections (shimming) or object induced perturbations of the magnetic field (hemorrhagic lesions, calcified tissue, air-tissue interfaces). Many techniques have been proposed to reduce the effects of macroscopic phase variations. Among these techniques are tuned pulse sequences, fitting techniques and reconstruction algorithms. These methods, however, suffer from one or more of the following drawbacks: they require longer acquisition times, require additional acquisitions, compensate only locally, can only be applied to multi-gradient echo data or may result in inaccurate results. In this work a generally applicable post-processing technique is presented to evaluate and compensate signal alterations invoked by first and second order macroscopic phase incoherences. In this technique, the derivatives of the signal phase are determined by applying the Fourier derivative theorem on the complex data. As a result, the phase derivatives are obtained without phase unwrapping and without compromising the resolution. The method is validated for single and multi-echo acquisitions by experiments on a co-axial cylinder phantom with known macroscopic field disturbances. The potential of the method is demonstrated on a multi-gradient echo acquisition on the head of a human volunteer. In general a first order correction is shown to be sufficient, however higher order correction is found to be beneficial near sharp transitions of the magnetic field. Copyright © 2011 Elsevier Inc. All rights reserved.

  9. Chemically grafted carbon nanotube surface coverage gradients. (United States)

    Shearer, Cameron J; Ellis, Amanda V; Shapter, Joseph G; Voelcker, Nicolas H


    Two approaches to producing gradients of vertically aligned single-walled carbon nanotubes (SWCNTs) on silicon surfaces by chemical grafting are presented here. The first approach involves the use of a porous silicon (pSi) substrate featuring a pore size gradient, which is functionalized with 3-aminopropyltriethoxysilane (APTES). Carboxylated SWCNTs are then immobilized on the topography gradient via carbodiimide coupling. Our results show that as the pSi pore size and porosity increase across the substrate the SWCNT coverage decreases concurrently. In contrast, the second gradient is an amine-functionality gradient produced by means of vapor-phase diffusion of APTES from a reservoir onto a silicon wafer where APTES attachment changes as a function of distance from the APTES reservoir. Carboxylated SWCNTs are then immobilized via carbodiimide coupling to the amine-terminated silicon gradient. Our observations confirm that with decreasing APTES density on the surface the coverage of the attached SWCNTs also decreases. These gradient platforms pave the way for the time-efficient optimization of SWCNT coverage for applications ranging from field emission to water filtration to drug delivery.

  10. Inside-out growth or inside-out quenching? Clues from colour gradients of local galaxies (United States)

    Lian, Jianhui; Yan, Renbin; Blanton, Michael; Kong, Xu


    We constrain the spatial gradient of star formation history (SFH) within galaxies using the colour gradients in NUV - u (where NUV stands for near-ultraviolet) and u - i for a local spatially resolved galaxy sample. By splitting each galaxy into an inner and an outer part, we find that most galaxies show negative gradients in these two colours. We first rule out dust extinction gradient and metallicity gradient as the dominant source for the colour gradient. Then using stellar population models, we explore variations in SFH to explain the colour gradients. As shown by our earlier work, a two-phase SFH consisting of an early secular evolution (growth) phase and a subsequent rapid evolution (quenching) phase is necessary to explain the observed colour distributions among galaxies. We explore two different inside-out growth models and two different inside-out quenching models by varying parameters of the SFH between inner and outer regions of galaxies. Two of the models can explain the observed range of colour gradients in NUV - u and u - i colours. We further distinguish them using an additional constraint provided by the u - i colour gradient distribution, under the assumption of constant galaxy formation rate and a common SFH followed by most galaxies. We find the best model is an inside-out growth model in which the inner region has a shorter e-folding time-scale in the growth phase than the outer region. More spatially resolved UV observations are needed to improve the significance of the result.

  11. Elucidate Innovation Performance of Technology-driven Mergers and Acquisitions

    Energy Technology Data Exchange (ETDEWEB)

    Huang, L.; Wang, K.; Yu, H.; Shang, L.; Mitkova, L.


    The importance and value of Mergers and Acquisitions (M&As) have increased with the expectancy to obtain key technology capabilities and rapid impact on innovation. This article develops an original analytical framework to elucidate the impact of the technology and product relatedness (similarity/complementarity) of the Technology-driven M&A’ partners on post-innovation performance. We present results drawing on a multiple case studies of Chinese High-Tech firms from three industries. (Author)

  12. Study of seismic data acquisition using physical modeling system; Butsuri model jikken sochi wo mochiita data shutoku gijutsu ni kansuru kento

    Energy Technology Data Exchange (ETDEWEB)

    Tsukui, R.; Tsuru, T. [Japan National Oil Corp., Tokyo (Japan). Technology Research Center; Matsuoka, T [Japan Petroleum Exploration Corp., Tokyo (Japan)


    For the physical modeling system of Technology Research Center, Japan National Oil Corporation, data acquisition on the ocean and ground can be simulated using models. This system can provide data for verification of the data processing and elastic wave simulation algorithm. This can also provide data for decision of experiment specifications by making a model simulating the underground structure of the given test field. The model used for the physical modeling system is a gradient multilayer model with six-layer structure. Depth migration before stacking was conducted using data obtained through two acquisition methods, i.e., up-dip acquisition and down-dip acquisition. The depth migration before stacking was performed for data obtained by up-dip acquisition in addition to the records obtained by down-dip acquisition. Consequently, a definite reflection surface was observed, which has not been observed from the processing results of down-dip acquisition data. 9 figs.

  13. Chemical gradients and chemotropism in yeast. (United States)

    Arkowitz, Robert A


    Chemical gradients of peptide mating pheromones are necessary for directional growth, which is critical for yeast mating. These gradients are generated by cell-type specific secretion or export and specific degradation in receiving cells. Spatial information is sensed by dedicated seven-transmembrane G-protein coupled receptors and yeast cells are able to detect extremely small differences in ligand concentration across their approximately 5-microm cell surface. Here, I will discuss our current knowledge of how cells detect and respond to such shallow chemical gradients and in particular what is known about the proteins that are involved in directional growth and the establishment of the polarity axis during yeast mating.

  14. Sound beam manipulation based on temperature gradients

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Feng [Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China); School of Physics & Electronic Engineering, Changshu Institute of Technology, Changshu 215500 (China); Quan, Li; Liu, Xiaozhou, E-mail:; Gong, Xiufen [Key Laboratory of Modern Acoustics, Institute of Acoustics and School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093 (China)


    Previous research with temperature gradients has shown the feasibility of controlling airborne sound propagation. Here, we present a temperature gradients based airborne sound manipulation schemes: a cylindrical acoustic omnidirectional absorber (AOA). The proposed AOA has high absorption performance which can almost completely absorb the incident wave. Geometric acoustics is used to obtain the refractive index distributions with different radii, which is then utilized to deduce the desired temperature gradients. Since resonant units are not applied in the scheme, its working bandwidth is expected to be broadband. The scheme is temperature-tuned and easy to realize, which is of potential interest to fields such as noise control or acoustic cloaking.

  15. Speciation gradients and the distribution of biodiversity. (United States)

    Schluter, Dolph; Pennell, Matthew W


    Global patterns of biodiversity are influenced by spatial and environmental variations in the rate at which new species form. We relate variations in speciation rates to six key patterns of biodiversity worldwide, including the species-area relationship, latitudinal gradients in species and genetic diversity, and between-habitat differences in species richness. Although they sometimes mirror biodiversity patterns, recent rates of speciation, at the tip of the tree of life, are often highest where species richness is low. Speciation gradients therefore shape, but are also shaped by, biodiversity gradients and are often more useful for predicting future patterns of biodiversity than for interpreting the past.

  16. Gradients of cortical hierarchy in Autism

    Directory of Open Access Journals (Sweden)

    Richard Bethlehem


    Full Text Available Autism is a developmental condition associated with altered functional connectivity. We propose to re-frame the functional connectivity alterations in terms of gradients that capture the functional hierarchy of cortical processing from sensory to default-mode network regions. We hypothesized that this hierarchy will be altered in ASD. To test that, we compared the scale of gradients in people with autism and healthy controls. The present results do not support our hypothesis. There are two alternative implications: either the processing hierarchies are preserved in autism or the scale of the gradients does not capture them. In the future we will attempt to settle which alternative is more likely.

  17. Discussion of liquid threshold pressure gradient


    Wang, Xiukun; James J. Sheng


    Some authors believe that a minimum pressure gradient (called threshold pressure gradient (TPG)) is required before a liquid starts to flow in a porous medium. In a tight or shale oil formation, this TPG phenomenon becomes more important, as it is more difficult for a fluid to flow. In this paper, experimental data on TPG published in the literature are carefully reviewed. What we found is that a very low flow velocity corresponding to a very low pressure gradient cannot be measured in the ex...

  18. 75 FR 27996 - Record of Decision (ROD) for the Training Land Acquisition (Including Purchase and Lease) at Fort... (United States)


    ...) for Training Land Acquisition at Fort Polk, Louisiana (March 2009). The ROD describes the Army's... Department of the Army Record of Decision (ROD) for the Training Land Acquisition (Including Purchase and... training land in Vernon and Rapides Parrish in the areas South of Peason Ridge, and to the North and East...

  19. 48 CFR 434.004 - Acquisition strategy. (United States)


    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Acquisition strategy. 434... CATEGORIES OF CONTRACTING MAJOR SYSTEM ACQUISITION General 434.004 Acquisition strategy. (a) The program... Systems Executive, a written charter outlining the authority, responsibility, accountability, and budget...

  20. Less noise, more activation: multi band acquisition schemes for auditory fMRI (United States)

    De Martino, Federico; Moerel, Michelle; Ugurbil, Kamil; Formisano, Elia; Yacoub, Essa


    Purpose To improve acquisition in fMRI studies of audition by using multiband (MB) gradient-echo echo planar imaging (GE-EPI). Methods Data were acquired at 3T (Siemens Skyra) with a 32-channel head coil. Functional responses were obtained by presenting stimuli (tones and natural sounds [voices, speech, music, tools, animal cries]) in silent gaps between image acquisitions. Two-fold slice acceleration (MB2) was compared to a standard GE-EPI (MB1). Coverage and sampling rate (TR=3s) were kept constant across acquisition schemes. The longer gap in MB2 scans was used to present: 1) sounds of the same length as in conventional GE-EPI (type1; 800 ms stimuli); 2) sounds of double the length (type 2; 1600 ms stimuli). Results Functional responses to all sounds (i.e. main effect) were stronger when acquired with slice acceleration (i.e. shorter acquisition time). The difference between voice and non-voice responses was greater in MB2 type1 acquisitions (i.e. same length sounds as GE-EPI but presented in a longer silent gap) than in standard GEEPI acquisitions (interaction effect). Conclusion Reducing the length of the scanner noise results in stronger functional responses. Longer “silent” periods (i.e. keeping the sound length the same as in standard acquisitions) result in stronger response to voice compared to non-voice stimuli. PMID:25105832

  1. Less noise, more activation: Multiband acquisition schemes for auditory functional MRI. (United States)

    De Martino, Federico; Moerel, Michelle; Ugurbil, Kamil; Formisano, Elia; Yacoub, Essa


    To improve acquisition in fMRI studies of audition by using multiband (MB) gradient-echo echo planar imaging (GE-EPI). Data were acquired at 3T (Siemens Skyra) with a 32-channel head coil. Functional responses were obtained by presenting stimuli [tones and natural sounds (voices, speech, music, tools, animal cries)] in silent gaps between image acquisitions. Two-fold slice acceleration (MB2) was compared with a standard GE-EPI (MB1). Coverage and sampling rate (TR = 3 s) were kept constant across acquisition schemes. The longer gap in MB2 scans was used to present: (i) sounds of the same length as in conventional GE-EPI (type 1; 800 ms stimuli); (ii) sounds of double the length (type 2; 1600 ms stimuli). Functional responses to all sounds (i.e., main effect) were stronger when acquired with slice acceleration (i.e., shorter acquisition time). The difference between voice and nonvoice responses was greater in MB2 type 1 acquisitions (i.e., same length sounds as GE-EPI but presented in a longer silent gap) than in standard GE-EPI acquisitions (interaction effect). Reducing the length of the scanner noise results in stronger functional responses. Longer "silent" periods (i.e., keeping the sound length the same as in standard acquisitions) result in stronger response to voice compared with nonvoice stimuli. © 2014 Wiley Periodicals, Inc.

  2. Integral Field Spectroscopy Surveys: Oxygen Abundance Gradients (United States)

    Sánchez, S. F.; Sánchez-Menguiano, L.


    We present here the recent results on our understanding of oxygen abundance gradients derived using Integral Field Spectroscopic surveys. In particular we analyzed more than 2124 datacubes corresponding to individual objects observed by the CALIFA (˜ 734 objects) and the public data by MaNGA (˜ 1390 objects), deriving the oxygen abundance gradient for each galaxy. We confirm previous results that indicate that the shape of this gradient is very similar for all galaxies with masses above 109.5M⊙, presenting in average a very similar slope of ˜ -0.04 dex within 0.5-2.0 re, with a possible drop in the inner regions (r109.5M⊙) the gradient seems to be flatter than for more massive ones. All these results agree with an inside-out growth of massive galaxies and indicate that low mass ones may still be growing in an outside in phase.

  3. Optimizing sampling approaches along ecological gradients

    DEFF Research Database (Denmark)

    Schweiger, Andreas; Irl, Severin D. H.; Steinbauer, Manuel


    1. Natural scientists and especially ecologists use manipulative experiments or field observations along gradients to differentiate patterns driven by processes from those caused by random noise. A well-conceived sampling design is essential for identifying, analysing and reporting underlying...

  4. Program predicts two-phase pressure gradients

    Energy Technology Data Exchange (ETDEWEB)

    Jacks, D.C.; Hill, A.D.


    The calculator program discussed, ORK, was designed for the HP-41CV hand-held calculator and uses the Orkiszewski correlation for predicting 2-phase pressure gradients in vertical tubulars. Accurate predictions of pressure gradients in flowing and gas lift wells over a wide range of well conditions can be obtained with this method, which was developed based on data from 148 wells. The correlation is one of the best generalized 2-phase pressure gradient prediction methods developed to date for vertical flow. It is unique in that hold-up is derived from observed physical phenomena, and the pressure gradient is related to the geometrical distribution of the liquid and gas phase (flow regime).

  5. Full Gradient Solution to Adaptive Hybrid Control (United States)

    Bean, Jacob; Schiller, Noah H.; Fuller, Chris


    This paper focuses on the adaptation mechanisms in adaptive hybrid controllers. Most adaptive hybrid controllers update two filters individually according to the filtered reference least mean squares (FxLMS) algorithm. Because this algorithm was derived for feedforward control, it does not take into account the presence of a feedback loop in the gradient calculation. This paper provides a derivation of the proper weight vector gradient for hybrid (or feedback) controllers that takes into account the presence of feedback. In this formulation, a single weight vector is updated rather than two individually. An internal model structure is assumed for the feedback part of the controller. The full gradient is equivalent to that used in the standard FxLMS algorithm with the addition of a recursive term that is a function of the modeling error. Some simulations are provided to highlight the advantages of using the full gradient in the weight vector update rather than the approximation.

  6. Vegetation patterns and environmental gradients in Benin

    NARCIS (Netherlands)

    Adomou, A.


    Key words: West Africa, Benin, vegetation patterns, floristic areas, phytogeography, chorology, floristic gradients, climatic factors, water availability, Dahomey Gap, threatened plants, biodiversity, conservation.Understanding plant species distribution patterns and the underlying factors is a

  7. Short echo time proton spectroscopy of the brain in healthy volunteers using an insert gradient head coil

    DEFF Research Database (Denmark)

    Gideon, P; Danielsen, E R; Schneider, M


    An insert gradient head coil with built-in X, Y, and Z gradients was used for localized proton spectroscopy in the brain of healthy volunteers, using short echo time stimulated echo acquisition mode (STEAM) sequences. Volume of interest size was 3.4 ml, repetition time was 6.0 s, and echo times w....../glutamate and myo-inositols. These compounds were more prominent within grey matter than within white matter. Rough estimations of metabolite concentrations using water as an internal standard were in good agreement with previous reports....

  8. Ultimate gradient in solid-state accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, D.H.


    The authors recall the motivation for research in high-gradient acceleration and the problems posed by a compact collider. They summarize the phenomena known to appear in operation of a solid-state structure with large fields, and research relevant to the question of the ultimate gradient. They take note of new concepts, and examine one in detail, a miniature particle accelerator based on an active millimeter-wave circuit and parallel particle beams.

  9. On fracture in finite strain gradient plasticity

    DEFF Research Database (Denmark)

    Martínez Pañeda, Emilio; Niordson, Christian Frithiof


    In this work a general framework for damage and fracture assessment including the effect of strain gradients is provided. Both mechanism-based and phenomenological strain gradient plasticity (SGP) theories are implemented numerically using finite deformation theory and crack tip fields are invest...... in the multiple parameter version of the phenomenological SGP theory. Since this also dominates the mechanics of indentation testing, results suggest that length parameters characteristic of mode I fracture should be inferred from nanoindentation....

  10. Microinstabilities in weak density gradient tokamak systems

    Energy Technology Data Exchange (ETDEWEB)

    Tang, W.M.; Rewoldt, G.; Chen, L.


    A prominent characteristic of auxiliary-heated tokamak discharges which exhibit improved (''H-mode type'') confinement properties is that their density profiles tend to be much flatter over most of the plasma radius. Depsite this favorable trend, it is emphasized here that, even in the limit of zero density gradient, low-frequency microinstabilities can persist due to the nonzero temperature gradient.

  11. Minimizing hallucination in Histogram of Oriented Gradients


    Ortiz, Javier; Bak, Slawomir; Koperski, Michał; Brémond, François


    International audience; Histogram of Oriented Gradients is one of the most extensively used image descriptors in computer vision. It has successfully been applied to various vision tasks such as localization, classification and recognition. As it mainly captures gradient strengths in an image, it is sensitive to local variations in illumination and contrast. In the result, a normalization of this descriptor turns out to be essential for good performance [3, 4]. Although different normal-izati...

  12. Thermal gradient analysis of solidifying casting

    Directory of Open Access Journals (Sweden)

    J. Suchoń


    Full Text Available For description of casting solidification and crystallization process the thermal derivative analysis (TDA is commonly used. Besides the process kinetics considered in TDA method to describe the solidification process, the thermal gradient analysis can be also used for this purpose [1, 2]. In conducted studies analysis of thermal gradient distribution inside the solidifying wedge casting was shown which enabled determination of heat flow intensity on casting section.

  13. Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake

    Directory of Open Access Journals (Sweden)

    Wang Tian


    Full Text Available The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index, varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity, i.e., a positive diversity–stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems.

  14. Phytoplankton Diversity Effects on Community Biomass and Stability along Nutrient Gradients in a Eutrophic Lake. (United States)

    Tian, Wang; Zhang, Huayong; Zhao, Lei; Zhang, Feifan; Huang, Hai


    The relationship between biodiversity and ecosystem functioning is a central issue in ecology, but how this relationship is affected by nutrient stress is still unknown. In this study, we analyzed the phytoplankton diversity effects on community biomass and stability along nutrient gradients in an artificial eutrophic lake. Four nutrient gradients, varying from slightly eutrophic to highly eutrophic states, were designed by adjusting the amount of polluted water that flowed into the lake. Mean phytoplankton biomass, species richness, and Shannon diversity index all showed significant differences among the four nutrient gradients. Phytoplankton community biomass was correlated with diversity (both species richness and Shannon diversity index), varying from positive to negative along the nutrient gradients. The influence of phytoplankton species richness on resource use efficiency (RUE) also changed from positive to negative along the nutrient gradients. However, the influence of phytoplankton Shannon diversity on RUE was not significant. Both phytoplankton species richness and Shannon diversity had a negative influence on community turnover (measured as community dissimilarity), i.e., a positive diversity-stability relationship. Furthermore, phytoplankton spatial stability decreased along the nutrient gradients in the lake. With increasing nutrient concentrations, the variability (standard deviation) of phytoplankton community biomass increased more rapidly than the average total biomass. Results in this study will be helpful in understanding the phytoplankton diversity effects on ecosystem functioning and how these effects are influenced by nutrient conditions in aquatic ecosystems.

  15. Microfluidic synthesis of composite cross-gradient materials for investigating cell-biomaterial interactions. (United States)

    He, Jiankang; Du, Yanan; Guo, Yuqi; Hancock, Matthew J; Wang, Ben; Shin, Hyeongho; Wu, Jinhui; Li, Dichen; Khademhosseini, Ali


    Combinatorial material synthesis is a powerful approach for creating composite material libraries for the high-throughput screening of cell-material interactions. Although current combinatorial screening platforms have been tremendously successful in identifying target (termed "hit") materials from composite material libraries, new material synthesis approaches are needed to further optimize the concentrations and blending ratios of the component materials. Here we employed a microfluidic platform to rapidly synthesize composite materials containing cross-gradients of gelatin and chitosan for investigating cell-biomaterial interactions. The microfluidic synthesis of the cross-gradient was optimized experimentally and theoretically to produce quantitatively controllable variations in the concentrations and blending ratios of the two components. The anisotropic chemical compositions of the gelatin/chitosan cross-gradients were characterized by Fourier transform infrared spectrometry and X-ray photoelectron spectrometry. The three-dimensional (3D) porous gelatin/chitosan cross-gradient materials were shown to regulate the cellular morphology and proliferation of smooth muscle cells (SMCs) in a gradient-dependent manner. We envision that our microfluidic cross-gradient platform may accelerate the material development processes involved in a wide range of biomedical applications. © 2010 Wiley Periodicals, Inc.

  16. Estimation of gradients in quantum metrology (United States)

    Altenburg, Sanah; Oszmaniec, Michał; Wölk, Sabine; Gühne, Otfried


    We develop a general theory to estimate magnetic field gradients in quantum metrology. We consider a system of N particles distributed on a line whose internal degrees of freedom interact with a magnetic field. Usually gradient estimation is based on precise measurements of the magnetic field at two different locations, performed with two independent groups of particles. This approach, however, is sensitive to fluctuations of the offset field determining the level splitting of the particles and results in collective dephasing. In this work, we use the framework of quantum metrology to assess the maximal accuracy for gradient estimation. For arbitrary positioning of particles, we identify optimal entangled and separable states, allowing the estimation of gradients with maximal accuracy, quantified by the quantum Fisher information. We also analyze the performance of states from the decoherence-free subspace (DFS), which are insensitive to the fluctuations of the magnetic offset field. We find that these states allow us to measure a gradient directly, without the necessity of estimating the magnetic offset field. Moreover, we show that DFS states attain a precision for gradient estimation comparable to the optimal entangled states. Finally, for the above classes of states, we find simple and feasible measurements saturating the quantum Cramér-Rao bound.

  17. 3D Gradient coil design - Toroidal surfaces (United States)

    While, Peter T.; Forbes, Larry K.; Crozier, Stuart


    Gradient coil design typically involves optimisation of current densities or coil windings on familiar cylindrical, planar, spherical or conical surfaces. In this paper, an analytic inverse method is presented for the theoretical design of toroidal transverse gradient coils. This novel geometry is based on previous work involving a 3D current density solution, in which the precise geometry of the gradient coils was obtained as part of the optimisation process. Regularisation is used to solve for the toroidal current densities, whereby the field error is minimised in conjunction with the total power of the coil. The method is applied to the design of unshielded and shielded, whole-body and head coil gradient systems. Preliminary coil windings displaying high gradient homogeneity, low inductance, high efficiency and good force balancing are displayed and discussed. Potential benefits associated with this morphology include self-shielding gradient sets, greater access to cooling mechanisms, a reduction in acoustic noise due to force-balancing, a lessening of patient claustrophobia and greater patient access for clinicians.

  18. Adaptive differentiation of traits related to resource use in a desert annual along a resource gradient. (United States)

    Brouillette, Larry C; Mason, Chase M; Shirk, Rebecca Y; Donovan, Lisa A


    • Plant resource-use traits are generally hypothesized to be adaptively differentiated for populations distributed along resource gradients. Although nutrient limitations are expected to select for resource-conservative strategies, water limitations may select for either resource-conservative or -acquisitive strategies. We test whether population differentiation reflects local adaptation for traits associated with resource-use strategies in a desert annual (Helianthus anomalus) distributed along a gradient of positively covarying water and nutrient availability. • We compared quantitative trait variation (Q(ST)) with neutral genetic differentiation (F(ST)), in a common garden glasshouse study, for leaf economics spectrum (LES) and related traits: photosynthesis (A(mass), A(area)), leaf nitrogen (N(mass), N(area)), leaf lifetime (LL), leaf mass per area (LMA), leaf water content (LWC), water-use efficiency (WUE, estimated as δ(13)C) and days to first flower (DFF). • Q(ST)-F(ST) differences support adaptive differentiation for Amass , N(mass), N(area), LWC and DFF. The trait combinations associated with drier and lower fertility sites represent correlated trait evolution consistent with the more resource-acquisitive end of the LES. There was no evidence for adaptive differentiation for A(area), LMA and WUE. • These results demonstrate that hot dry environments can selectively favor correlated evolution of traits contributing to a resource-acquisitive and earlier reproduction 'escape' strategy, despite lower fertility. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  19. 75 FR 77721 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-47; Introduction (United States)


    ... ADMINISTRATION 48 CFR Chapter 1 Federal Acquisition Regulation; Federal Acquisition Circular 2005-47... Council and the Defense Acquisition Regulations Council (Councils) in this Federal Acquisition Circular... interagency acquisitions, not just those made under the Economy Act authority. A new subsection 17.502-1 is...

  20. Conservation implications of deforestation across an elevational gradient in the Eastern Arc Mountains, Tanzania

    DEFF Research Database (Denmark)

    Hall, Jaclyn; Burgess, Neil David; Lovett, Jon


    Deforestation is a major threat to the conservation of biodiversity, especially within global centers of endemism for plants and animals. Elevation, the major environmental gradient in mountain regions of the world, produces a rapid turnover of species, where some species may exist only in narrow...... elevational ranges. We use newly compiled datasets to assess the conservation impact of deforestation on threatened trees across an elevational gradient within the Eastern Arc Mountains of Tanzania. The Eastern Arc has suffered an estimated 80% total loss in historical forest area and has lost 25% of forest...

  1. Computational models of syntactic acquisition. (United States)

    Yang, Charles


    The computational approach to syntactic acquisition can be fruitfully pursued by integrating results and perspectives from computer science, linguistics, and developmental psychology. In this article, we first review some key results in computational learning theory and their implications for language acquisition. We then turn to examine specific learning models, some of which exploit distributional information in the input while others rely on a constrained space of hypotheses, yet both approaches share a common set of characteristics to overcome the learning problem. We conclude with a discussion of how computational models connects with the empirical study of child grammar, making the case for computationally tractable, psychologically plausible and developmentally realistic models of acquisition. WIREs Cogn Sci 2012, 3:205-213. doi: 10.1002/wcs.1154 For further resources related to this article, please visit the WIREs website. Copyright © 2011 John Wiley & Sons, Ltd.

  2. To Get or Not to Get the Kaust Library E-Resources Acquisition Experience


    Ramli, Rindra M.; Kabli, Ola A.


    In the challenging times of budget cuts and reviews, libraries are faced with issues such as justifying acquisition, negotiating deals and reviewing current subscriptions (pertaining to electronic resources) among others. With the rapid growth of electronic resources, libraries have to continuously assess their acquisition models and policies to constantly ensure that they are balancing their budget and users’ needs as well. This paper highlights the role played by Technical and Digital Servi...

  3. Tailoring the Acquisition Process in the U.S. Department of Defense (United States)


    the associate directors, Paul DeLuca and Marc Robbins , for their insightful com- ments on this research. xvii Abbreviations ADM Acquisition the SASSA program. Of these six, one was judged as a neutral contribution while five were judged as helpful in achiev- ing the program goals. No...tailored processes were judged as nega- tive contributions to meeting the rapid space acquisitions goals. (Johnson, 2010, p. 4) Also in regard to SE

  4. Mergers and Acquisitions - Case Study


    Vedele, Sebastiano


    The thesis generally talks about mergers & acquisitions, discussing definitions, differences and reasons behind an M&A. I have analyzed what is a merge and what is an acquisition. Why companies combine themselves through an M&A. What are advantages and disadvantages about an M&A. After that the work is followed by a case study, which focuses on Fiat and Chrysler. With regards to this point, the case touches all the steps of the agreement between the two car automakers providing numbers, perce...

  5. Optimized Fast and Sensitive Acquisition Methods for Shotgun Proteomics on a Quadrupole Orbitrap Mass Spectrometer

    DEFF Research Database (Denmark)

    Kelstrup, Christian D; Young, Clifford; Lavallee, Richard


    (HCD) tandem mass spectra due to the parallel mode of operation, where the generation, filling, and storage of fragment ions can be performed while simultaneously measuring another ion packet in the Orbitrap mass analyzer. In this study, data-dependent acquisition methods for "fast" or "sensitive...... h of analysis time. At sample loads below 125 ng, a 156 ms HCD acquisition method improved the sensitivity, mass accuracy, and quality of data and enabled us to identify 30% more proteins and peptides than the faster scanning method. A similar effect was observed when the LC gradient was extended...... to 2 or 3 h for the analysis of complex mammalian whole cell lysates. Using a 3 h LC gradient, the sensitive method enabled identification of more than 4000 proteins from 1 µg of tryptic HeLa digest, which was almost 200 more identifications compared to the faster scanning method. Our results...

  6. [First language acquisition research and theories of language acquisition]. (United States)

    Miller, S; Jungheim, M; Ptok, M


    In principle, a child can seemingly easily acquire any given language. First language acquisition follows a certain pattern which to some extent is found to be language independent. Since time immemorial, it has been of interest why children are able to acquire language so easily. Different disciplinary and methodological orientations addressing this question can be identified. A selective literature search in PubMed and Scopus was carried out and relevant monographies were considered. Different, partially overlapping phases can be distinguished in language acquisition research: whereas in ancient times, deprivation experiments were carried out to discover the "original human language", the era of diary studies began in the mid-19th century. From the mid-1920s onwards, behaviouristic paradigms dominated this field of research; interests were focussed on the determination of normal, average language acquisition. The subsequent linguistic period was strongly influenced by the nativist view of Chomsky and the constructivist concepts of Piaget. Speech comprehension, the role of speech input and the relevance of genetic disposition became the centre of attention. The interactionist concept led to a revival of the convergence theory according to Stern. Each of these four major theories--behaviourism, cognitivism, interactionism and nativism--have given valuable and unique impulses, but no single theory is universally accepted to provide an explanation of all aspects of language acquisition. Moreover, it can be critically questioned whether clinicians consciously refer to one of these theories in daily routine work and whether therapies are then based on this concept. It remains to be seen whether or not new theories of grammar, such as the so-called construction grammar (CxG), will eventually change the general concept of language acquisition.

  7. Optical Coherence Tomography in the UK Biobank Study - Rapid Automated Analysis of Retinal Thickness for Large Population-Based Studies.

    Directory of Open Access Journals (Sweden)

    Pearse A Keane

    Full Text Available To describe an approach to the use of optical coherence tomography (OCT imaging in large, population-based studies, including methods for OCT image acquisition, storage, and the remote, rapid, automated analysis of retinal thickness.In UK Biobank, OCT images were acquired between 2009 and 2010 using a commercially available "spectral domain" OCT device (3D OCT-1000, Topcon. Images were obtained using a raster scan protocol, 6 mm x 6 mm in area, and consisting of 128 B-scans. OCT image sets were stored on UK Biobank servers in a central repository, adjacent to high performance computers. Rapid, automated analysis of retinal thickness was performed using custom image segmentation software developed by the Topcon Advanced Biomedical Imaging Laboratory (TABIL. This software employs dual-scale gradient information to allow for automated segmentation of nine intraretinal boundaries in a rapid fashion.67,321 participants (134,642 eyes in UK Biobank underwent OCT imaging of both eyes as part of the ocular module. 134,611 images were successfully processed with 31 images failing segmentation analysis due to corrupted OCT files or withdrawal of subject consent for UKBB study participation. Average time taken to call up an image from the database and complete segmentation analysis was approximately 120 seconds per data set per login, and analysis of the entire dataset was completed in approximately 28 days.We report an approach to the rapid, automated measurement of retinal thickness from nearly 140,000 OCT image sets from the UK Biobank. In the near future, these measurements will be publically available for utilization by researchers around the world, and thus for correlation with the wealth of other data collected in UK Biobank. The automated analysis approaches we describe may be of utility for future large population-based epidemiological studies, clinical trials, and screening programs that employ OCT imaging.

  8. Suffix Knowledge: Acquisition and Applications (United States)

    Ward, Jeremy; Chuenjundaeng, Jitlada


    The purpose of this study is to investigate L2 learners' knowledge of complex word part analysis ("word-building"), with particular reference to two issues: suffix acquisition and to the use of word families as a counting tool. Subjects were two groups of EAP students in a Thai university. Results suggest that (1) the use of word…

  9. Instructional Model for Concept Acquisition. (United States)

    Tennyson, Robert D.

    The purpose of this paper is to demonstrate the feasibility of applying research variables for concept acquisition into a generalized instructional model for teaching concepts. This paper does not present the methodology for the decision/selection stages in designing the actual instruction task, but offers references to other sources which give…

  10. [Language acquisition and statistical learning]. (United States)

    Breitenstein, C; Knecht, S


    Statistical learning is a basic mechanism of information processing in the human brain. The purpose lies in the extraction of probabilistic regularities from the multitude of sensory inputs. Principles of statistical learning contribute significantly to language acquisition and presumably also to language recovery following stroke. The empirical database presented in this manuscript demonstrates that the process of word segmentation, acquisition of a lexicon, and acquisition of simple grammatical rules can be entirely explained through statistical learning. Statistical learning is mediated by changes in synaptic weights in neuronal networks. The concept therefore stands at the transition to molecular biology and pharmacology of the neuronal synapse. It still remains to be shown if all aspects of language acquisition can be explained through statistical learning and which regions of the brain are involved in or capable of statistical learning. Principles of effective language training are obvious already. Most important is the massive, repeated interactive exposure. Conscious processing of the stimulus material may not be essential. The crucial principle is a high cooccurrence of language and corresponding sensory processes. This requires a more intense training frequency than traditional aphasia treatment programs provide.

  11. Profiling Vocabulary Acquisition in Irish (United States)

    O'Toole, Ciara; Fletcher, Paul


    Investigations into early vocabulary development, including the timing of the acquisition of nouns, verbs and closed-class words, have produced conflicting results, both within and across languages. Studying vocabulary development in Irish can contribute to this area, as it has potentially informative features such as a VSO word order, and…

  12. Analog Input Data Acquisition Software (United States)

    Arens, Ellen


    DAQ Master Software allows users to easily set up a system to monitor up to five analog input channels and save the data after acquisition. This program was written in LabVIEW 8.0, and requires the LabVIEW runtime engine 8.0 to run the executable.

  13. Essays on mergers and acquisitions

    NARCIS (Netherlands)

    Faelten, A.I.


    “Essays on Mergers and Acquisitions" tackles some of the most prominent business challenges related to M&A activity. The Introduction examines the reasons why deals fail through well-known case studies; Chapter 1 presents a new index measuring countries M&A maturity worldwide; Chapter 2 focus on the

  14. Behavioural View of Language Acquisition

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 13; Issue 5. Behavioural View of Language Acquisition. Rajeev Sangal. Book Review Volume 13 Issue 5 May 2008 pp 487-489. Fulltext. Click here to view fulltext PDF. Permanent link: ...

  15. Language Acquisition and Language Revitalization (United States)

    O'Grady, William; Hattori, Ryoko


    Intergenerational transmission, the ultimate goal of language revitalization efforts, can only be achieved by (re)establishing the conditions under which an imperiled language can be acquired by the community's children. This paper presents a tutorial survey of several key points relating to language acquisition and maintenance in children,…

  16. The SINQ data acquisition environment

    Energy Technology Data Exchange (ETDEWEB)

    Maden, D. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)


    The data acquisition environment for the neutron scattering instruments supported by LNS at SINQ is described. The intention is to provide future users with the necessary background to the computing facilities on site rather than to present a user manual for the on-line system. (author) 5 figs., 6 refs.

  17. Low-gradient single-sided NMR sensor for one-shot profiling of human skin. (United States)

    Van Landeghem, Maxime; Danieli, Ernesto; Perlo, Juan; Blümich, Bernhard; Casanova, Federico


    This paper describes a shimming approach useful to reduce the gradient strength of the magnetic field generated by single-sided sensors simultaneously maximizing its uniformity along the lateral directions of the magnet. In this way, the thickness of the excited sensitive volume can be increased without compromising the depth resolution of the sensor. By implementing this method on a standard U-shaped magnet, the gradient strength was reduced one order of magnitude. In the presence of a gradient of about 2 T/m, slices of 2mm could be profiled with a resolution that ranges from 25 μm at the center of the slice to 50 μm at the borders. This sensor is of particular advantage for applications, where the scanning range is of the order of the excited slice. In those cases, the full profile is measured in a single excitation experiment, eliminating the need for repositioning the excited slice across the depth range to complete the profile as occurs with standard high gradient sensors. Besides simplifying the experimental setup, the possibility to move from a point-by-point measurement to the simultaneous acquisition of the full profile led to the shortening of the experimental time. A further advantage of performing the experiment under a smaller static gradient is a reduction of the diffusion attenuation affecting the signal decay measured with a CPMG sequence, making it possible to measure the T(2) of samples with high diffusivity (comparable to the water diffusivity). The performance of the sensor in terms of resolution and sensitivity is first evaluated and compared with conventional singled-sided sensors of higher gradient strength using phantoms of known geometry and relaxation times. Then, the device is used to profile the structure of human skin in vivo. To understand the contrast between the different skin layers, the distribution of relaxation times T(2) and diffusion coefficients is spatially resolved along the depth direction. Copyright © 2011 Elsevier Inc

  18. Optoelectrofluidic field separation based on light-intensity gradients. (United States)

    Lee, Sanghyun; Park, Hyun Jin; Yoon, Jin Sung; Kang, Kwan Hyoung


    Optoelectrofluidic field separation (OEFS) of particles under light -intensity gradient (LIG) is reported, where the LIG illumination on the photoconductive layer converts the short-ranged dielectrophoresis (DEP) force to the long-ranged one. The long-ranged DEP force can compete with the hydrodynamic force by alternating current electro-osmosis (ACEO) over the entire illumination area for realizing effective field separation of particles. In the OEFS system, the codirectional illumination and observation induce the levitation effect, compensating the attenuation of the DEP force under LIG illumination by slightly floating particles from the surface. Results of the field separation and concentration of diverse particle pairs (0.82-16 mum) are well demonstrated, and conditions determining the critical radius and effective particle manipulation are discussed. The OEFS with codirectional LIG strategy could be a promising particle manipulation method in many applications where a rapid manipulation of biological cells and particles over the entire working area are of interest.

  19. Charged particle beam scanning using deformed high gradient insulator (United States)

    Chen, Yu -Jiuan


    Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

  20. Buffer gas acquisition and storage (United States)

    Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.


    The acquisition and storage of buffer gases (primarily argon and nitrogen) from the Mars atmosphere provides a valuable resource for blanketing and pressurizing fuel tanks and as a buffer gas for breathing air for manned missions. During the acquisition of carbon dioxide (CO2), whether by sorption bed or cryo-freezer, the accompanying buffer gases build up in the carbon dioxide acquisition system, reduce the flow of CO2 to the bed, and lower system efficiency. It is this build up of buffer gases that provide a convenient source, which must be removed, for efficient capture of CO2. Removal of this buffer gas barrier greatly improves the charging rate of the CO2 acquisition bed and, thereby, maintains the fuel production rates required for a successful mission. Consequently, the acquisition, purification, and storage of these buffer gases are important goals of ISRU plans. Purity of the buffer gases is a concern e.g., if the CO2 freezer operates at 140 K, the composition of the inert gas would be approximately 21 percent CO2, 50 percent nitrogen, and 29 percent argon. Although there are several approaches that could be used, this effort focused on a hollow-fiber membrane (HFM) separation method. This study measured the permeation rates of CO2, nitrogen (N2), and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193 K and 10 kPa to 300 kPa. Concentrations were measured with a gas chromatograph. The end result was data necessary to design a system that could separate CO2, N2, and Ar. .

  1. Buffer Gas Acquisition and Storage (United States)

    Parrish, Clyde F.; Lueck, Dale E.; Jennings, Paul A.; Callahan, Richard A.; Delgado, H. (Technical Monitor)


    The acquisition and storage of buffer gases (primarily argon and nitrogen) from the Mars atmosphere provides a valuable resource for blanketing and pressurizing fuel tanks and as a buffer gas for breathing air for manned missions. During the acquisition of carbon dioxide (CO2), whether by sorption bed or cryo-freezer, the accompanying buffer gases build up in the carbon dioxide acquisition system, reduce the flow of CO2 to the bed, and lower system efficiency. It is this build up of buffer gases that provide a convenient source, which must be removed, for efficient capture Of CO2 Removal of this buffer gas barrier greatly improves the charging rate of the CO2 acquisition bed and, thereby, maintains the fuel production rates required for a successful mission. Consequently, the acquisition, purification, and storage of these buffer gases are important goals of ISRU plans. Purity of the buffer gases is a concern e.g., if the CO, freezer operates at 140 K, the composition of the inert gas would be approximately 21 percent CO2, 50 percent nitrogen, and 29 percent argon. Although there are several approaches that could be used, this effort focused on a hollow-fiber membrane (HFM) separation method. This study measured the permeation rates of CO2, nitrogen (ND, and argon (Ar) through a multiple-membrane system and the individual membranes from room temperature to 193K and 10 kpa to 300 kPa. Concentrations were measured with a gas chromatograph that used a thermoconductivity (TCD) detector with helium (He) as the carrier gas. The general trend as the temperature was lowered was for the membranes to become more selective, In addition, the relative permeation rates between the three gases changed with temperature. The end result was to provide design parameters that could be used to separate CO2 from N2 and Ar.

  2. Gradient-echo MR imaging of the cervical spine: evaluation of extradural disease. (United States)

    VanDyke, C; Ross, J S; Tkach, J; Masaryk, T J; Modic, M T


    A prospective study was undertaken on 204 consecutive patients comparing low flip angle gradient-echo and T1-weighted spin-echo techniques in the MR evaluation of cervical extradural disease. Four patient groups were studied with varying gradient-echo TEs (6 or 13 msec) and flip angles (10 degrees or 60 degrees). Images were evaluated independently for contrast behavior and anatomy, then directly compared for conspicuity of lesions. The FLASH sequences (especially with a 10 degrees flip angle) produced better conspicuity of disease in half the imaging time. T1-weighted spin-echo sequences were more sensitive to marrow changes and intradural disease. The short TE sequence (6 msec) did not produce any diagnostic advantage over the longer TE sequence (13 msec). A fast and sensitive MR examination for cervical extradural disease combines a sagittal T1-weighted spin-echo acquisition with sagittal and axial FLASH 10 degrees sequences.

  3. Rapid Prototyping Laboratory (United States)

    Federal Laboratory Consortium — The ARDEC Rapid Prototyping (RP) Laboratory was established in December 1992 to provide low cost RP capabilities to the ARDEC engineering community. The Stratasys,...

  4. Evidence of counter-gradient growth in western pond turtles (Actinemys marmorata) across thermal gradients (United States)

    Snover, Melissa; Adams, Michael J.; Ashton, Donald T.; Bettaso, Jamie B.; Welsh, Hartwell H.


    Counter-gradient growth, where growth per unit temperature increases as temperature decreases, can reduce the variation in ectothermic growth rates across environmental gradients. Understanding how ectothermic species respond to changing temperatures is essential to their conservation and management due to human-altered habitats and changing climates.

  5. Momentum-weighted conjugate gradient descent algorithm for gradient coil optimization. (United States)

    Lu, Hanbing; Jesmanowicz, Andrzej; Li, Shi-Jiang; Hyde, James S


    MRI gradient coil design is a type of nonlinear constrained optimization. A practical problem in transverse gradient coil design using the conjugate gradient descent (CGD) method is that wire elements move at different rates along orthogonal directions (r, phi, z), and tend to cross, breaking the constraints. A momentum-weighted conjugate gradient descent (MW-CGD) method is presented to overcome this problem. This method takes advantage of the efficiency of the CGD method combined with momentum weighting, which is also an intrinsic property of the Levenberg-Marquardt algorithm, to adjust step sizes along the three orthogonal directions. A water-cooled, 12.8 cm inner diameter, three axis torque-balanced gradient coil for rat imaging was developed based on this method, with an efficiency of 2.13, 2.08, and 4.12 mT.m(-1).A(-1) along X, Y, and Z, respectively. Experimental data demonstrate that this method can improve efficiency by 40% and field uniformity by 27%. This method has also been applied to the design of a gradient coil for the human brain, employing remote current return paths. The benefits of this design include improved gradient field uniformity and efficiency, with a shorter length than gradient coil designs using coaxial return paths. Copyright 2003 Wiley-Liss, Inc.

  6. Reconstruction for limited-projection fluorescence molecular tomography based on projected restarted conjugate gradient normal residual. (United States)

    Cao, Xu; Zhang, Bin; Liu, Fei; Wang, Xin; Bai, Jing


    Limited-projection fluorescence molecular tomography (FMT) can greatly reduce the acquisition time, which is suitable for resolving fast biology processes in vivo but suffers from severe ill-posedness because of the reconstruction using only limited projections. To overcome the severe ill-posedness, we report a reconstruction method based on the projected restarted conjugate gradient normal residual. The reconstruction results of two phantom experiments demonstrate that the proposed method is feasible for limited-projection FMT. © 2011 Optical Society of America

  7. Nonlinear conjugate gradient methods in micromagnetics (United States)

    Fischbacher, J.; Kovacs, Alexander; Oezelt, Harald; Schrefl, T.; Exl, L.; Fidler, J.; Suess, D.; Sakuma, N.; Yano, M.; Kato, A.; Shoji, T.; Manabe, A.


    Conjugate gradient methods for energy minimization in micromagnetics are compared. The comparison of analytic results with numerical simulation shows that standard conjugate gradient method may fail to produce correct results. A method that restricts the step length in the line search is introduced, in order to avoid this problem. When the step length in the line search is controlled, conjugate gradient techniques are a fast and reliable way to compute the hysteresis properties of permanent magnets. The method is applied to investigate demagnetizing effects in NdFe12 based permanent magnets. The reduction of the coercive field by demagnetizing effects is μ0ΔH = 1.4 T at 450 K.

  8. Gradient Solvent Vapor Annealing of Thin Films (United States)

    Albert, Julie; Bogart, Timothy; Lewis, Ronald; Epps, Thomas


    The development of block copolymer materials for emerging nanotechnologies requires an understanding of how surface energy/chemistry and annealing conditions affect thin film self-assembly. Specifically, in solvent vapor annealing (SVA), the use of solvent mixtures and the manipulation of solvent vapor concentration are promising approaches for obtaining a desired morphology or nanostructure orientation. We designed and fabricated solvent-resistant devices to produce discrete SVA gradients in composition and/or concentration to efficiently explore SVA parameter space. We annealed copolymer films containing poly(styrene), poly(isoprene), and/or poly(methyl methacrylate) blocks, monitored film thicknesses during annealing, and characterized film morphologies with atomic force microscopy. Morphological changes across the gradients such as the transformation from parallel cylinders to spheres with increasing solvent selectivity provided insight into thin film self-assembly, and the gradient device has enabled us to determine transition compositions and/or concentrations.

  9. Conjugate gradient algorithms using multiple recursions

    Energy Technology Data Exchange (ETDEWEB)

    Barth, T.; Manteuffel, T.


    Much is already known about when a conjugate gradient method can be implemented with short recursions for the direction vectors. The work done in 1984 by Faber and Manteuffel gave necessary and sufficient conditions on the iteration matrix A, in order for a conjugate gradient method to be implemented with a single recursion of a certain form. However, this form does not take into account all possible recursions. This became evident when Jagels and Reichel used an algorithm of Gragg for unitary matrices to demonstrate that the class of matrices for which a practical conjugate gradient algorithm exists can be extended to include unitary and shifted unitary matrices. The implementation uses short double recursions for the direction vectors. This motivates the study of multiple recursion algorithms.

  10. Dynamics of gradient formation by intracellular shuttling

    Energy Technology Data Exchange (ETDEWEB)

    Berezhkovskii, Alexander M. [Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892 (United States); Shvartsman, Stanislav Y. [Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544 (United States)


    A number of important cellular functions rely on the formation of intracellular protein concentration gradients. Experimental studies discovered a number of mechanisms for the formation of such gradients. One of the mechanisms relies on the intracellular shuttling of a protein that interconverts between the two states with different diffusivities, under the action of two enzymes, one of which is localized to the plasma membrane, whereas the second is uniformly distributed in the cytoplasm. Recent work reported an analytical solution for the steady state gradient in this mechanism, obtained in the framework of a one-dimensional reaction-diffusion model. Here, we study the dynamics in this model and derive analytical expressions for the Laplace transforms of the time-dependent concentration profiles in terms of elementary transcendental functions. Inverting these transforms numerically, one can obtain time-dependent concentration profiles of the two forms of the protein.

  11. Collective chemotaxis through noisy multicellular gradient sensing

    CERN Document Server

    Varennes, Julien; Mugler, Andrew


    Collective cell migration in response to a chemical cue occurs in many biological processes such as morphogenesis and cancer metastasis. Clusters of migratory cells in these systems are capable of responding to gradients of less than 1% difference in chemical concentration across a cell length. Multicellular systems are extremely sensitive to their environment and while the limits to multicellular sensing are becoming known, how this information leads to coherent migration remains poorly understood. We develop a computational model of multicellular sensing and migration in which groups of cells collectively measure noisy chemical gradients. The output of the sensing process is coupled to individual cells polarization to model migratory behavior. Through the use of numerical simulations, we find that larger clusters of cells detect the gradient direction with higher precision and thus achieve stronger polarization bias, but larger clusters also induce more drag on collective motion. The trade-off between these...

  12. Gradients in Planarian Regeneration and Homeostasis (United States)

    Adell, Teresa; Cebrià, Francesc; Saló, Emili


    Planarian regeneration was one of the first models in which the gradient concept was developed. Morphological studies based on the analysis of the regeneration rates of planarian fragments from different body regions, the generation of heteromorphoses, and experiments of tissue transplantation led T.H. Morgan (1901) and C.M Child (1911) to postulate different kinds of gradients responsible for the regenerative process in these highly plastic animals. However, after a century of research, the role of morphogens in planarian regeneration has yet to be demonstrated. This may change soon, as the sequencing of the planarian genome and the possibility of performing gene functional analysis by RNA interference (RNAi) have led to the isolation of elements of the bone morphogenetic protein (BMP), Wnt, and fibroblast growth factor (FGF) pathways that control patterning and axial polarity during planarian regeneration and homeostasis. Here, we discuss whether the actions of these molecules could be based on morphogenetic gradients. PMID:20182600

  13. Inversion gradients for acoustic VTI wavefield tomography

    KAUST Repository

    Li, Vladimir


    Wavefield tomography can handle complex subsurface geology better than ray-based techniques and, ultimately, provide a higher resolution. Here, we implement forward and adjoint wavefield extrapolation for VTI (transversely isotropic with a vertical symmetry axis) media using a generalized pseudospectral operator based on a separable approximation for the P-wave dispersion relation. This operator is employed to derive the gradients of the differential semblance optimization (DSO) and modified image-power objective functions. We also obtain the gradient expressions for a data-domain objective function that can more easily incorporate borehole information necessary for stable VTI velocity analysis. These gradients are similar to the ones obtained with a space-time finite-difference (FD) scheme for a system of coupled wave equations but the pseudospectral method is not hampered by the imprint of the shear-wave artifact. Numerical examples also show the potential advantages of the modified image-power objective function in estimating the anellipticity parameter η.

  14. 48 CFR 307.104-70 - Acquisition strategy. (United States)


    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Acquisition strategy. 307... AND ACQUISITION PLANNING ACQUISITION PLANNING Acquisition Planning 307.104-70 Acquisition strategy... designated by the HHS CIO, DASFMP, the CAO, or the cognizant HCA) shall prepare an acquisition strategy using...

  15. The Influence Of Temperature Gradient On Stereological Parameters Of Carbide Phase On Cross-Section Of Abrasive Wear Resistant Chromium Cast Iron

    Directory of Open Access Journals (Sweden)

    Studnicki A.


    Full Text Available In the paper analysis of temperature gradient and parameters of structure on casting cross-section of abrasive wear resistant chromium cast iron at carbon content of 2,5%wt. and chromium 17%wt. with nickel and molybdenum additives are presented. The castings were made with use of special tester ϕ100mm (method of temperature gradient and derivative analysis with temperature recording in many points from thermal centre to surface (to mould of casting. Registered cooling curves were used to describe the temperature gradient on cross-section of analyzed casting. On the basis of determined curves of temperature gradient measurement fields were selected to make the quantitative studies of structure. The results of studies show significant influence of temperature gradient on quantitative parameters of chromium cast iron structure. Moreover was affirmed that exists a critical temperature gradient for which is present rapid change of quantitative parameters of chromium cast iron structure.

  16. On lower order strain gradient plasticity theories

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Hutchinson, J. W.


    By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter the t...... the tangential moduli governing increments of stress and strain. It is shown that the modification is far from benign from a mathematical standpoint, changing the qualitative character of solutions and leading to a new type of localization that appears to be unphysical....

  17. Spectral Projected Gradient Methods: Review and Perspectives

    Directory of Open Access Journals (Sweden)

    Ernesto G. Birgin


    Full Text Available Over the last two decades, it has been observed that using the gradient vector as a search direction in large-scale optimization may lead to efficient algorithms. The effectiveness relies on choosing the step lengths according to novel ideas that are related to the spectrum of the underlying local Hessian rather than related to the standard decrease in the objective function. A review of these so-called spectral projected gradient methods for convex constrained optimization is presented. To illustrate the performance of these low-cost schemes, an optimization problem on the set of positive definite matrices is described.

  18. Improving dimensionality reduction with spectral gradient descent. (United States)

    Memisevic, Roland; Hinton, Geoffrey


    We introduce spectral gradient descent, a way of improving iterative dimensionality reduction techniques. The method uses information contained in the leading eigenvalues of a data affinity matrix to modify the steps taken during a gradient-based optimization procedure. We show that the approach is able to speed up the optimization and to help dimensionality reduction methods find better local minima of their objective functions. We also provide an interpretation of our approach in terms of the power method for finding the leading eigenvalues of a symmetric matrix and verify the usefulness of the approach in some simple experiments.

  19. Gradient Elasticity Formulations for Micro/Nanoshells

    Directory of Open Access Journals (Sweden)

    Bohua Sun


    Full Text Available The focus of this paper is on illustrating how to extend the second author’s gradient theory of elasticity to shells. Three formulations are presented based on the implicit gradient elasticity constitutive relation 1 -ld2∇2σij=Cijkl(1-ls2∇2εkl and its two approximations 1+ls2∇2-ld2∇2σij=Cijklεkl and σij=Cijkl(1+ld2∇2-ls2∇2εkl.

  20. Mergers and acquisitions processes in Ukraine




    The paper deals with characteristics of merges and acquisitions market in Ukraine. The study describes main directions and motives of integration processes at domestic enterprises. Efficient ways are suggested to improve processes of merges and acquisitions in Ukraine.

  1. Technological Integration of Acquisitions in Digital Industries

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Toppenberg, Gustav


    Acquisitions have become essential tools to retain the technological edge in digital industries. This paper analyses the technological integration challenges in such acquisitions. Acquirers in digital industries are typically platform leaders in platform markets. They acquire (a) other platform...

  2. Acquisition management of the Global Transportation Network (United States)


    This report discusses the acquisition management of the Global transportation Network by the U.S. Transportation Command. This report is one in a series of audit reports addressing DoD acquisition management of information technology systems. The Glo...

  3. Plant Size and Competitive Dynamics along Nutrient Gradients. (United States)

    Goldberg, Deborah E; Martina, Jason P; Elgersma, Kenneth J; Currie, William S


    Resource competition theory in plants has focused largely on resource acquisition traits that are independent of size, such as traits of individual leaves or roots or proportional allocation to different functions. However, plants also differ in maximum potential size, which could outweigh differences in module-level traits. We used a community ecosystem model called mondrian to investigate whether larger size inevitably increases competitive ability and how size interacts with nitrogen supply. Contrary to the conventional wisdom that bigger is better, we found that invader success and competitive ability are unimodal functions of maximum potential size, such that plants that are too large (or too small) are disproportionately suppressed by competition. Optimal size increases with nitrogen supply, even when plants compete for nitrogen only in a size-symmetric manner, although adding size-asymmetric competition for light does substantially increase the advantage of larger size at high nitrogen. These complex interactions of plant size and nitrogen supply lead to strong nonlinearities such that small differences in nitrogen can result in large differences in plant invasion success and the influence of competition along productivity gradients.

  4. Up-gradient transport in a probabilistic transport model

    DEFF Research Database (Denmark)

    Gavnholt, J.; Juul Rasmussen, J.; Garcia, O.E.


    The transport of particles or heat against the driving gradient is studied by employing a probabilistic transport model with a characteristic particle step length that depends on the local concentration or heat gradient. When this gradient is larger than a prescribed critical value, the standard....... These results supplement recent works by van Milligen [Phys. Plasmas 11, 3787 (2004)], which applied Levy distributed step sizes in the case of supercritical gradients to obtain the up-gradient transport. (c) 2005 American Institute of Physics....

  5. COLDEX New Data Acquisition Framework

    CERN Document Server

    Grech, Christian


    COLDEX (COLD bore EXperiment) is an experiment of the TE-VSC group installed in the Super Proton Synchrotron (SPS) which mimics a LHC type cryogenic vacuum system. In the framework of the High Luminosity upgrade of the LHC (HL-LHC project), COLDEX has been recommissioned in 2014 in order to validate carbon coatings performances at cryogenic temperature with LHC type beams. To achieve this mission, a data acquisition system is needed to retrieve and store information from the different experiment’s systems (vacuum, cryogenics, controls, safety) and perform specific calculations. This work aimed to completely redesign, implement, test and operate a brand new data acquisition framework based on communication with the experiment’s PLCs for the devices potentially available over network. The communication protocol to the PLCs is based on data retrieval both from CERN middleware infrastructures (CMW, JAPC) and on a novel open source Simatic S7 data exchange package over TCP/IP (libnodave).

  6. Music and early language acquisition. (United States)

    Brandt, Anthony; Gebrian, Molly; Slevc, L Robert


    Language is typically viewed as fundamental to human intelligence. Music, while recognized as a human universal, is often treated as an ancillary ability - one dependent on or derivative of language. In contrast, we argue that it is more productive from a developmental perspective to describe spoken language as a special type of music. A review of existing studies presents a compelling case that musical hearing and ability is essential to language acquisition. In addition, we challenge the prevailing view that music cognition matures more slowly than language and is more difficult; instead, we argue that music learning matches the speed and effort of language acquisition. We conclude that music merits a central place in our understanding of human development.

  7. Music and Early Language Acquisition

    Directory of Open Access Journals (Sweden)

    Anthony K. Brandt


    Full Text Available Language is typically viewed as fundamental to human intelligence. Music, while recognized as a human universal, is often treated as an ancillary ability—one dependent on or derivative of language. In contrast, we argue that it is more productive from a developmental perspective to describe spoken language as a special type of music. A review of existing studies presents a compelling case that musical hearing and ability is essential to language acquisition. In addition, the authors challenge the prevailing view that music cognition matures more slowly than language and is more difficult; instead, the authors present evidence that music learning matches the speed and effort of language acquisition. We conclude that music merits a central place in our understanding of human development.

  8. The ALICE data acquisition system

    CERN Document Server

    Carena, F; Chapeland, S; Chibante Barroso, V; Costa, F; Dénes, E; Divià, R; Fuchs, U; Grigore, A; Kiss, T; Simonetti, G; Soós, C; Telesca, A; Vande Vyvre, P; Von Haller, B


    In this paper we describe the design, the construction, the commissioning and the operation of the Data Acquisition (DAQ) and Experiment Control Systems (ECS) of the ALICE experiment at the CERN Large Hadron Collider (LHC). The DAQ and the ECS are the systems used respectively for the acquisition of all physics data and for the overall control of the experiment. They are two computing systems made of hundreds of PCs and data storage units interconnected via two networks. The collection of experimental data from the detectors is performed by several hundreds of high-speed optical links. We describe in detail the design considerations for these systems handling the extreme data throughput resulting from central lead ions collisions at LHC energy. The implementation of the resulting requirements into hardware (custom optical links and commercial computing equipment), infrastructure (racks, cooling, power distribution, control room), and software led to many innovative solutions which are described together with ...

  9. Music and Early Language Acquisition (United States)

    Brandt, Anthony; Gebrian, Molly; Slevc, L. Robert


    Language is typically viewed as fundamental to human intelligence. Music, while recognized as a human universal, is often treated as an ancillary ability – one dependent on or derivative of language. In contrast, we argue that it is more productive from a developmental perspective to describe spoken language as a special type of music. A review of existing studies presents a compelling case that musical hearing and ability is essential to language acquisition. In addition, we challenge the prevailing view that music cognition matures more slowly than language and is more difficult; instead, we argue that music learning matches the speed and effort of language acquisition. We conclude that music merits a central place in our understanding of human development. PMID:22973254

  10. GRAVITY acquisition camera: characterization results (United States)

    Anugu, Narsireddy; Garcia, Paulo; Amorim, Antonio; Wiezorrek, Erich; Wieprecht, Ekkehard; Eisenhauer, Frank; Ott, Thomas; Pfuhl, Oliver; Gordo, Paulo; Perrin, Guy; Brandner, Wolfgang; Straubmeier, Christian; Perraut, Karine


    GRAVITY acquisition camera implements four optical functions to track multiple beams of Very Large Telescope Interferometer (VLTI): a) pupil tracker: a 2×2 lenslet images four pupil reference lasers mounted on the spiders of telescope secondary mirror; b) field tracker: images science object; c) pupil imager: reimages telescope pupil; d) aberration tracker: images a Shack-Hartmann. The estimation of beam stabilization parameters from the acquisition camera detector image is carried out, for every 0.7 s, with a dedicated data reduction software. The measured parameters are used in: a) alignment of GRAVITY with the VLTI; b) active pupil and field stabilization; c) defocus correction and engineering purposes. The instrument is now successfully operational on-sky in closed loop. The relevant data reduction and on-sky characterization results are reported.

  11. Tracker Readout ASIC for Proton Computed Tomography Data Acquisition. (United States)

    Johnson, Robert P; Dewitt, Joel; Holcomb, Cole; Macafee, Scott; Sadrozinski, Hartmut F-W; Steinberg, David


    A unique CMOS chip has been designed to serve as the front-end of the tracking detector data acquisition system of a pre-clinical prototype scanner for proton computed tomography (pCT). The scanner is to be capable of measuring one to two million proton tracks per second, so the chip must be able to digitize the data and send it out rapidly while keeping the front-end amplifiers active at all times. One chip handles 64 consecutive channels, including logic for control, calibration, triggering, buffering, and zero suppression. It outputs a formatted cluster list for each trigger, and a set of field programmable gate arrays merges those lists from many chips to build the events to be sent to the data acquisition computer. The chip design has been fabricated, and subsequent tests have demonstrated that it meets all of its performance requirements, including excellent low-noise performance.

  12. Agricultural land acquisitions: a lens on Southeast Asia

    Energy Technology Data Exchange (ETDEWEB)

    Polack, Emily


    Recent years have seen 'land grabbing' emerge as a big issue in media houses across the world, with reporters quick to write about deals involving millions of hectares, particularly within Africa. Yet large-scale land acquisitions are not a purely African phenomenon. Other parts of the world are also subject to the global land rush. Home to emerging economies with profit potential, Southeast Asia has become ever more appealing to investors from both within and beyond the region seeking to include agriculture in their portfolios. Regional agribusiness companies are booming. And rapid change in land ownership and use is already taking place. Set against a backdrop of insecure rights and weak land governance, land acquisitions here are posing significant threats to local livelihoods and environments alike.

  13. 32 CFR 644.7 - Acquisition lines. (United States)


    ... HANDBOOK Project Planning Civil Works § 644.7 Acquisition lines. (a) Tentative acquisition lines. As..., in accordance with sound real estate practices. Accordingly, fringe tracts will not be acquired until the final acquisition lines are approved by the Division Engineer. (b) Submission. As soon as possible...

  14. Sustaining an Acquisition-based Growth Strategy

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Toppenberg, Gustav; Shanks, Graeme

    Value creating acquisitions are a major challenge for many firms. Our case study of Cisco Systems shows that an advanced Enterprise Architecture (EA) capability can contribute to the acquisition process through a) preparing the acquirer to become ‘acquisition ready’, b) identifying resource......-based growth strategy over time....

  15. The acquisition of speech and language. (United States)

    Woodfield, T A


    There are many theories behind speech and language acquisition. The role of parents in social interaction with their infant to facilitate speech and language acquisition is of paramount importance. Several pathological influences may hinder speech and language acquisition. Children's nurses need knowledge and understanding of how speech and language are acquired.

  16. Managing IT Integration Risk in Acquisitions

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Kettinger, William J.


    The article discusses a framework for evaluating risk of information technology (IT) integration in acquisitions. Topics include the use of the experience of serial acquirer Trelleborg AB to show the merits of the framework for managing the risk and to determine low-risk acquisitions......, the importance of managing IT integration risk, and various risk areas for acquisition IT integration....

  17. Acquisition of HPLC-Mass Spectrometer (United States)


    31-Jan-2015 Approved for Public Release; Distribution Unlimited Final Report: Acquisition of HPLC -Mass Spectrometer The views, opinions and/or findings...published in peer-reviewed journals: Final Report: Acquisition of HPLC -Mass Spectrometer Report Title The acquisition of the mass spectrometer has been a

  18. Including secondary illumination in seismic acquisition design

    NARCIS (Netherlands)

    Kumar, A.; Blacquière, G.


    A subsurface image obtained from seismic data is influenced by the acquisition geometry, as it contains an acquisition foot-print which can obscure the true reflection response of the subsurface. Hence, the acquisition geometry should be designed in such a way that it allows high-quality images and

  19. Information Acquisition, Analysis and Integration (United States)


    Deep neural networks with random Gaussian weights: A universal classification strategy?,” IEEE Trans. Signal Processing, 2016, to appear. 2. M. applications, new camera designs, and numerous DoD and industrial technology transfers. 15. SUBJECT TERMS Information acquisition, integration...Defense (ONR, ARO, NGA), to the NIH, and to industry (Adobe, LSS, etc). As mentioned above, these also resulted in numerous awards and become the core

  20. Arduino based data acquisition system


    Veramendi Fernández, Megara


    This project explains the design and functioning of an Arduino based data acquisition system. By using Arduino UNO and LabVIEW software, it has been possible to measure different parameters such as temperature, illuminance, movement or even the presence of magnetic fields. Controlling the microcontroller on a very easy way from a computer has been possible thanks to the interface offered by National Instruments software. Wireless communication with the microcontroller has also been introduced...

  1. WRATS Integrated Data Acquisition System (United States)

    Piatak, David J.


    The Wing and Rotor Aeroelastic Test System (WRATS) data acquisition system (DAS) is a 64-channel data acquisition display and analysis system specifically designed for use with the WRATS 1/5-scale V-22 tiltrotor model of the Bell Osprey. It is the primary data acquisition system for experimental aeroelastic testing of the WRATS model for the purpose of characterizing the aeromechanical and aeroelastic stability of prototype tiltrotor configurations. The WRATS DAS was also used during aeroelastic testing of Bell Helicopter Textron s Quad-Tiltrotor (QTR) design concept, a test which received international attention. The LabVIEW-based design is portable and capable of powering and conditioning over 64 channels of dynamic data at sampling rates up to 1,000 Hz. The system includes a 60-second circular data archive, an integrated model swashplate excitation system, a moving block damping application for calculation of whirl flutter mode subcritical damping, a loads and safety monitor, a pilot-control console display, data analysis capabilities, and instrumentation calibration functions. Three networked computers running custom-designed LabVIEW software acquire data through National Instruments data acquisition hardware. The aeroelastic model (see figure) was tested with the DAS at two facilities at NASA Langley, the Transonic Dynamics Tunnel (TDT) and the Rotorcraft Hover Test Facility (RHTF). Because of the need for seamless transition between testing at these facilities, DAS is portable. The software is capable of harmonic analysis of periodic time history data, Fast Fourier Transform calculations, power spectral density calculations, and on-line calibration of test instrumentation. DAS has a circular buffer archive to ensure critical data is not lost in event of model failure/incident, as well as a sample-and-hold capability for phase-correct time history data.

  2. Aerial robotic data acquisition system

    Energy Technology Data Exchange (ETDEWEB)

    Hofstetter, K.J.; Hayes, D.W.; Pendergast, M.M. [Westinghouse Savannah River Co., Aiken, SC (United States); Corban, J.E. [Guided Systems Technologies, Atlanta, GA (United States)


    A small, unmanned aerial vehicle (UAV), equipped with sensors for physical and chemical measurements of remote environments, is described. A miniature helicopter airframe is used as a platform for sensor testing and development. The sensor output is integrated with the flight control system for real-time, interactive, data acquisition and analysis. Pre-programmed flight missions will be flown with several sensors to demonstrate the cost-effective surveillance capabilities of this new technology.

  3. The Cybersecurity Challenge in Acquisition (United States)


    modern supply chain will add vulnerabilities to these linked supplier systems. Introduction Cyber Threat Challenges The accelerated growth in cyber...cyber challenges of their systems at the right level of detail is the only viable solution to this problem in the long run. Securing Supply Chains turn introduce new vulnerabilities in the organization and must be managed by those acquisition specialists focused most on the supply chain

  4. Complex System Governance for Acquisition (United States)


    indicate a similar meaning for governance as the CSG meaning? and (3) Is there any concrete indication that the tools and methods of CSG would have...formulation of the structure and execution of a system (e.g., acquisition program). This structure and its execution ultimately determine the level...missing cost, schedule, performance expectations). Instead, more fundamental systems based pathologies (i.e., aberrations from healthy system conditions

  5. A review of spelling acquisition

    DEFF Research Database (Denmark)

    Dich, Nadya; Cohn, Abigail C.


    This review article discusses how empirical data on the acquisition of spelling by children inform the question of the psycholinguistic validity of the phoneme, a concept central (at least implicitly) to most phonological theories. The paper reviews data on children's early spelling attempts...... is offered suggesting that orthographic and phonological knowledge develop together into a hierarchy of representations. While the idea of multidimensional phonological representations has been previously entertained in psycholinguistic literature, none of the previous proposals has explicitly incorporated...

  6. Fast Access Data Acquisition System

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Vladimir Katsman


    Our goal in this program is to develop Fast Access Data Acquisition System (FADAS) by combining the flexibility of Multilink's GaAs and InP electronics and electro-optics with an extremely high data rate for the efficient handling and transfer of collider experimental data. This novel solution is based on Multilink's and Los Alamos National Laboratory's (LANL) unique components and technologies for extremely fast data transfer, storage, and processing.

  7. 3D joint inversion of gravity-gradient and borehole gravity data (United States)

    Geng, Meixia; Yang, Qingjie; Huang, Danian


    Borehole gravity is increasingly used in mineral exploration due to the advent of slim-hole gravimeters. Given the full-tensor gradiometry data available nowadays, joint inversion of surface and borehole data is a logical next step. Here, we base our inversions on cokriging, which is a geostatistical method of estimation where the error variance is minimised by applying cross-correlation between several variables. In this study, the density estimates are derived using gravity-gradient data, borehole gravity and known densities along the borehole as a secondary variable and the density as the primary variable. Cokriging is non-iterative and therefore is computationally efficient. In addition, cokriging inversion provides estimates of the error variance for each model, which allows direct assessment of the inverse model. Examples are shown involving data from a single borehole, from multiple boreholes, and combinations of borehole gravity and gravity-gradient data. The results clearly show that the depth resolution of gravity-gradient inversion can be improved significantly by including borehole data in addition to gravity-gradient data. However, the resolution of borehole data falls off rapidly as the distance between the borehole and the feature of interest increases. In the case where the borehole is far away from the target of interest, the inverted result can be improved by incorporating gravity-gradient data, especially all five independent components for inversion.

  8. MR Measurement Technique of Rapidly Switched Gradient Magnetic Fields in MR Tomography

    Czech Academy of Sciences Publication Activity Database

    Bartušek, Karel; Gescheidtová, E.


    Roč. 29, č. 4 (2005), s. 675-686 ISSN 0937-9347 Institutional research plan: CEZ:AV0Z20650511 Keywords : MR tomography * gradiernt magnet ic field * IF method * IFSE method * IFSES method * spin echo Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 0.743, year: 2005

  9. Rapid separation of Arabidopsis male gametophyte developmental stages using a Percoll gradient

    Czech Academy of Sciences Publication Activity Database

    Dupľáková, Nikoleta; Dobrev, Petre; Reňák, David; Honys, David


    Roč. 11, č. 10 (2016), s. 1817-1832 ISSN 1754-2189 R&D Projects: GA ČR GP13-41444P Institutional support: RVO:61389030 Keywords : Arabidopsis thaliana * pollen * male gametophyte Subject RIV: ED - Physiology Impact factor: 10.032, year: 2016

  10. Miniaturized Antimicrobial Susceptibility Test by Combining Concentration Gradient Generation and Rapid Cell Culturing


    Kim, Samuel C.; Stefano Cestellos-Blanco; Keisuke Inoue; Zare, Richard N.


    Effective treatment of bacterial infection relies on timely diagnosis and proper prescription of antibiotic drugs. The antimicrobial susceptibility test (AST) is one of the most crucial experimental procedures, providing the baseline information for choosing effective antibiotic agents and their dosages. Conventional methods, however, require long incubation times or significant instrumentation costs to obtain test results. We propose a lab-on-a-chip approach to perform AST in a simple, econo...

  11. Confidence-Based Feature Acquisition (United States)

    Wagstaff, Kiri L.; desJardins, Marie; MacGlashan, James


    Confidence-based Feature Acquisition (CFA) is a novel, supervised learning method for acquiring missing feature values when there is missing data at both training (learning) and test (deployment) time. To train a machine learning classifier, data is encoded with a series of input features describing each item. In some applications, the training data may have missing values for some of the features, which can be acquired at a given cost. A relevant JPL example is that of the Mars rover exploration in which the features are obtained from a variety of different instruments, with different power consumption and integration time costs. The challenge is to decide which features will lead to increased classification performance and are therefore worth acquiring (paying the cost). To solve this problem, CFA, which is made up of two algorithms (CFA-train and CFA-predict), has been designed to greedily minimize total acquisition cost (during training and testing) while aiming for a specific accuracy level (specified as a confidence threshold). With this method, it is assumed that there is a nonempty subset of features that are free; that is, every instance in the data set includes these features initially for zero cost. It is also assumed that the feature acquisition (FA) cost associated with each feature is known in advance, and that the FA cost for a given feature is the same for all instances. Finally, CFA requires that the base-level classifiers produce not only a classification, but also a confidence (or posterior probability).

  12. Large Airborne Full Tensor Gradient Data Inversion Based on a Non-Monotone Gradient Method (United States)

    Sun, Yong; Meng, Zhaohai; Li, Fengting


    Following the development of gravity gradiometer instrument technology, the full tensor gravity (FTG) data can be acquired on airborne and marine platforms. Large-scale geophysical data can be obtained using these methods, making such data sets a number of the "big data" category. Therefore, a fast and effective inversion method is developed to solve the large-scale FTG data inversion problem. Many algorithms are available to accelerate the FTG data inversion, such as conjugate gradient method. However, the conventional conjugate gradient method takes a long time to complete data processing. Thus, a fast and effective iterative algorithm is necessary to improve the utilization of FTG data. Generally, inversion processing is formulated by incorporating regularizing constraints, followed by the introduction of a non-monotone gradient-descent method to accelerate the convergence rate of FTG data inversion. Compared with the conventional gradient method, the steepest descent gradient algorithm, and the conjugate gradient algorithm, there are clear advantages of the non-monotone iterative gradient-descent algorithm. Simulated and field FTG data were applied to show the application value of this new fast inversion method.

  13. Development of High-Gradient Dielectric Laser-Driven Particle Accelerator Structures

    Energy Technology Data Exchange (ETDEWEB)

    Byer, Robert L. [Stanford Univ., CA (United States). Edward L. Ginzton Lab.


    The thrust of Stanford's program is to conduct research on high-gradient dielectric accelerator structures driven with high repetition-rate, tabletop infrared lasers. The close collaboration between Stanford and SLAC (Stanford Linear Accelerator Center) is critical to the success of this project, because it provides a unique environment where prototype dielectric accelerator structures can be rapidly fabricated and tested with a relativistic electron beam.

  14. Weakening of lower tropospheric temperature gradient between ...

    Indian Academy of Sciences (India)

    e-mail: The study shows that in the scenario of global warming temperature gradient (TG) between Indian landmass and Arabian Sea/Bay of Bengal is significantly decreasing in the lower troposphere with maxima around 850hPa. TG during pre-monsoon (March to May) is ...

  15. Hydrodynamic Gradient Expansion in Gauge Theory Plasmas,

    NARCIS (Netherlands)

    Heller, M.P.; Janik, R.A.; Witaszczyk, P


    We utilize the fluid-gravity duality to investigate the large order behavior of hydrodynamic gradient expansion of the dynamics of a gauge theory plasma system. This corresponds to the inclusion of dissipative terms and transport coefficients of very high order. Using the dual gravity description,

  16. Gradient lasso for Cox proportional hazards model. (United States)

    Sohn, Insuk; Kim, Jinseog; Jung, Sin-Ho; Park, Changyi


    There has been an increasing interest in expressing a survival phenotype (e.g. time to cancer recurrence or death) or its distribution in terms of a subset of the expression data of a subset of genes. Due to high dimensionality of gene expression data, however, there is a serious problem of collinearity in fitting a prediction model, e.g. Cox's proportional hazards model. To avoid the collinearity problem, several methods based on penalized Cox proportional hazards models have been proposed. However, those methods suffer from severe computational problems, such as slow or even failed convergence, because of high-dimensional matrix inversions required for model fitting. We propose to implement the penalized Cox regression with a lasso penalty via the gradient lasso algorithm that yields faster convergence to the global optimum than do other algorithms. Moreover the gradient lasso algorithm is guaranteed to converge to the optimum under mild regularity conditions. Hence, our gradient lasso algorithm can be a useful tool in developing a prediction model based on high-dimensional covariates including gene expression data. Results from simulation studies showed that the prediction model by gradient lasso recovers the prognostic genes. Also results from diffuse large B-cell lymphoma datasets and Norway/Stanford breast cancer dataset indicate that our method is very competitive compared with popular existing methods by Park and Hastie and Goeman in its computational time, prediction and selectivity. R package glcoxph is available at

  17. Instabilities in power law gradient hardening materials

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Tvergaard, Viggo


    Tension and compression instabilities are investigated for specimens with dimensions in the micron range. A finite strain generalization of a higher order strain gradient plasticity theory is implemented in a finite element scheme capable of modeling power law hardening materials. Effects...

  18. Mass balance gradients and climatic change

    NARCIS (Netherlands)

    Oerlemans, J.; Hoogendoorn, N.C.


    It is generally assumed that the mass-balance gradient on glaciers is more or less conserved under climatic change. In studies of the dynamic response of glaciers to climatic change, one of the following assumptions is normally made: (i) the mass-balance perturbation is independent of altitude

  19. Lactate uptake against a concentration gradient

    DEFF Research Database (Denmark)

    Nordström, Carl-Henrik; Nielsen, Troels Halfeld; Nielsen, Hans Boye


    The recently published article by Jalloh et al (Jalloh I, Helmy A, Shannon RJ, Gallagher CN, Menon D, Carpenter K, Hutchinson P. Lactate uptake by the injured human brain - evidence from an arterio-venous gradient and cerebral microdialysis study. J Neurotrauma. 2013 Aug 22. [Epub ahead of print...

  20. Density Gradient Columns for Chemical Displays. (United States)

    Guenther, William B.


    Procedures for preparing density gradient columns for chemical displays are presented. They include displays illustrating acid-base reactions, metal ion equilibria, and liquid density. The lifetime of these metastable displays is surprising, some lasting for months in display cabinets. (JN)

  1. GOCE gravitational gradients along the orbit

    NARCIS (Netherlands)

    Bouman, J.; Fiorot, S.; Fuchs, M.; Gruber, T.; Schrama, E.J.O.; Tscherning, C.; Veicherts, M.; Visser, P.N.A.M.


    GOCE is ESA’s gravity field mission and the first satellite ever that measures gravitational gradients in space, that is, the second spatial derivatives of the Earth’s gravitational potential. The goal is to determine the Earth’s mean gravitational field with unprecedented accuracy at spatial

  2. Proton gradients at the origin of life. (United States)

    Lane, Nick


    Chemiosmotic coupling - the harnessing of electrochemical ion gradients across membranes to drive metabolism - is as universally conserved as the genetic code. As argued previously in these pages, such deep conservation suggests that ion gradients arose early in evolution, and might have played a role in the origin of life. Alkaline hydrothermal vents harbour pH gradients of similar polarity and magnitude to those employed by modern cells, one of many properties that make them attractive models for life's origin. Their congruence with the physiology of anaerobic autotrophs that use the acetyl CoA pathway to fix CO2 gives the alkaline vent model broad appeal to biologists. Recently, however, a paper by Baz Jackson criticized the hypothesis, concluding that natural pH gradients were unlikely to have played any role in the origin of life. Unfortunately, Jackson mainly criticized his own interpretations of the theory, not what the literature says. This counterpoint is intended to set the record straight. © 2017 WILEY Periodicals, Inc.

  3. GOCE gravity gradient data for lithospheric modeling

    NARCIS (Netherlands)

    Bouman, J.; Ebbing, J.; Meekes, S.; Fattah, R.A.; Fuchs, M.; Gradmann, S.; Haagmans, R.; Lieb, V.; Schmidt, M.; Dettmering, D.; Bosch, W.


    The Gravity field and steady-state Ocean Circulation Explorer (GOCE) is the European Space Agency's (ESA)satellite gravity mission to determine the Earth's mean gravity field. GOCE delivers gravity gradients, anew type of satellite data. We study how these data can improve modeling of the Earth's

  4. Gradient computation for VTI acoustic wavefield tomography

    KAUST Repository

    Li, Vladimir


    Wavefield tomography can handle complex subsurface geology better than ray-based techniques and, ultimately, provide a higher resolution. Here, we implement forward and adjoint wavefield extrapolation for VTI (transversely isotropic with a vertical symmetry axis) media using a pseudospectral operator that employes a separable approximation of the P-wave dispersion relation. This operator is employed to derive the gradients of the differential semblance optimization (DSO) and modified stack-power objective functions. We also obtain the gradient expressions for the data-domain objective function, which can incorporate borehole information necessary for stable VTI velocity analysis. These gradients are compared to the ones obtained with a space-time finite-difference (FD) scheme for a system of coupled wave equations. Whereas the kernels computed with the two wave-equation operators are similar, the pseudospectral method is not hampered by the imprint of the shear-wave artifact. Numerical examples also show that the modified stack-power objective function produces cleaner gradients than the more conventional DSO operator.

  5. Annular beam with segmented phase gradients

    Directory of Open Access Journals (Sweden)

    Shubo Cheng


    Full Text Available An annular beam with a single uniform-intensity ring and multiple segments of phase gradients is proposed in this paper. Different from the conventional superposed vortices, such as the modulated optical vortices and the collinear superposition of multiple orbital angular momentum modes, the designed annular beam has a doughnut intensity distribution whose radius is independent of the phase distribution of the beam in the imaging plane. The phase distribution along the circumference of the doughnut beam can be segmented with different phase gradients. Similar to a vortex beam, the annular beam can also exert torques and rotate a trapped particle owing to the orbital angular momentum of the beam. As the beam possesses different phase gradients, the rotation velocity of the trapped particle can be varied along the circumference. The simulation and experimental results show that an annular beam with three segments of different phase gradients can rotate particles with controlled velocities. The beam has potential applications in optical trapping and optical information processing.

  6. Annular beam with segmented phase gradients

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Shubo; Wu, Liang [School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Tao, Shaohua, E-mail: [School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Hunan Key Laboratory for Super-microstructure and Ultrafast Process, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China)


    An annular beam with a single uniform-intensity ring and multiple segments of phase gradients is proposed in this paper. Different from the conventional superposed vortices, such as the modulated optical vortices and the collinear superposition of multiple orbital angular momentum modes, the designed annular beam has a doughnut intensity distribution whose radius is independent of the phase distribution of the beam in the imaging plane. The phase distribution along the circumference of the doughnut beam can be segmented with different phase gradients. Similar to a vortex beam, the annular beam can also exert torques and rotate a trapped particle owing to the orbital angular momentum of the beam. As the beam possesses different phase gradients, the rotation velocity of the trapped particle can be varied along the circumference. The simulation and experimental results show that an annular beam with three segments of different phase gradients can rotate particles with controlled velocities. The beam has potential applications in optical trapping and optical information processing.

  7. 75 FR 77745 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-47; Small Entity Compliance Guide (United States)


    ... Acquisition Regulation; Federal Acquisition Circular 2005-47; Small Entity Compliance Guide AGENCIES... a summary of rules appearing in Federal Acquisition Circular (FAC) 2005-47, which amend the FAR. An... 17.5 now addresses all interagency acquisitions, not just those made under the Economy Act authority...

  8. 76 FR 68044 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-54; Small Entity Compliance Guide (United States)


    ... Acquisition Regulation; Federal Acquisition Circular 2005-54; Small Entity Compliance Guide AGENCY: Department... rules appearing in Federal Acquisition Circular (FAC) 2005-54, which amend the Federal Acquisition... (FAR Case 2009-006) This final rule amends the FAR to implement Executive Order (E.O.) 13494, Economy...

  9. 76 FR 68013 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-54; Introduction (United States)


    ... Space Administration 48 CFR Part 1 Federal Acquisition Regulation; Federal Acquisition Circular 2005-54... Acquisition Circular 2005-54; Introduction AGENCIES: Department of Defense (DoD), General Services...) rules agreed to by DoD, GSA, and NASA in this Federal Acquisition Circular (FAC) 2005-54. A companion...

  10. Extracellular Processing of Molecular Gradients by Eukaryotic Cells Can Improve Gradient Detection Accuracy (United States)

    Segota, Igor; Franck, Carl


    Eukaryotic cells sense molecular gradients by measuring spatial concentration variation through the difference in the number of occupied receptors to which molecules can bind. They also secrete enzymes that degrade these molecules, and it is presently not well understood how this affects the local gradient perceived by cells. Numerical and analytical results show that these enzymes can substantially increase the signal-to-noise ratio of the receptor difference and allow cells to respond to a much broader range of molecular concentrations and gradients than they would without these enzymes.

  11. GPS, GNSS, and Ionospheric Density Gradients (United States)

    Kintner, P. M.; O'Hanlon, B.; Humphreys, T. E.


    Ionospheric density and density gradients affect GNSS signals in two ways. They can introduce ranging errors or irregularities that form on the density gradients producing scintillation. Here we focus on the issue of ranging errors. There are two approaches to mitigating ranging errors produced by ionospheric density gradients which can be 20-30 m during major magnetic storms. The first approach is to use a reference receiver(s) to determine the ionospheric contribution to ranging errors. The ranging error is then transmitted to the user for correction within the mobile receiver. This approach is frequently referred to as differential GPS and, when multiple reference receivers are used, the system is referred to as an augmentation system. This approach is vulnerable to ionospheric gradients depending on the reference receiver spacing(s) and latency in applying the correction within the mobile receiver. The second approach is to transmit navigation signals at two frequencies and then use the relative delay between the two signals to both estimate the ranging error and calculate the correct range. Currently the dual frequency technique is used by US military receivers with an encryption key and some civilian receivers which must be stationary and average over times long compared to those required for navigation. However, the technology of space based radio navigation is changing. GPS will soon be a system with three frequencies and multiple codes. Furthermore Europe, Russia, and China are developing independent systems to complement and compete with GPS while India and Japan are developing local systems to enhance GPS performance in their regions. In this talk we address two questions. How do density gradients affect augmentation systems including the social consequences and will the new GPS/GNSS systems with multiple civilian frequencies be able to remove ionospheric errors. The answers are not at all clear.

  12. Rapid Airplane Parametric Input Design (RAPID) (United States)

    Smith, Robert E.


    RAPID is a methodology and software system to define a class of airplane configurations and directly evaluate surface grids, volume grids, and grid sensitivity on and about the configurations. A distinguishing characteristic which separates RAPID from other airplane surface modellers is that the output grids and grid sensitivity are directly applicable in CFD analysis. A small set of design parameters and grid control parameters govern the process which is incorporated into interactive software for 'real time' visual analysis and into batch software for the application of optimization technology. The computed surface grids and volume grids are suitable for a wide range of Computational Fluid Dynamics (CFD) simulation. The general airplane configuration has wing, fuselage, horizontal tail, and vertical tail components. The double-delta wing and tail components are manifested by solving a fourth order partial differential equation (PDE) subject to Dirichlet and Neumann boundary conditions. The design parameters are incorporated into the boundary conditions and therefore govern the shapes of the surfaces. The PDE solution yields a smooth transition between boundaries. Surface grids suitable for CFD calculation are created by establishing an H-type topology about the configuration and incorporating grid spacing functions in the PDE equation for the lifting components and the fuselage definition equations. User specified grid parameters govern the location and degree of grid concentration. A two-block volume grid about a configuration is calculated using the Control Point Form (CPF) technique. The interactive software, which runs on Silicon Graphics IRIS workstations, allows design parameters to be continuously varied and the resulting surface grid to be observed in real time. The batch software computes both the surface and volume grids and also computes the sensitivity of the output grid with respect to the input design parameters by applying the precompiler tool

  13. Study of a Liquid Plug-Flow Thermal Cycling Technique Using a Temperature Gradient-Based Actuator

    Directory of Open Access Journals (Sweden)

    Yusuke Fuchiwaki


    Full Text Available Easy-to-use thermal cycling for performing rapid and small-volume DNA amplification on a single chip has attracted great interest in the area of rapid field detection of biological agents. For this purpose, as a more practical alternative to conventional continuous flow thermal cycling, liquid plug-flow thermal cycling utilizes a thermal gradient generated in a serpentine rectangular flow microchannel as an actuator. The transit time and flow speed of the plug flow varied drastically in each temperature zone due to the difference in the tension at the interface between temperature gradients. According to thermal distribution analyses in microfluidics, the plug flow allowed for a slow heating process, but a fast cooling process. The thermal cycle of the microfluid was consistent with the recommended temperature gradient for PCR. Indeed, amplification efficiency of the plug flow was superior to continuous flow PCR, and provided an impressive improvement over previously-reported flow microchannel thermal cycling techniques.

  14. Words, rules, and mechanisms of language acquisition. (United States)

    Endress, Ansgar D; Bonatti, Luca L


    We review recent artificial language learning studies, especially those following Endress and Bonatti (Endress AD, Bonatti LL. Rapid learning of syllable classes from a perceptually continuous speech stream. Cognition 2007, 105:247-299), suggesting that humans can deploy a variety of learning mechanisms to acquire artificial languages. Several experiments provide evidence for multiple learning mechanisms that can be deployed in fluent speech: one mechanism encodes the positions of syllables within words and can be used to extract generalization, while the other registers co-occurrence statistics of syllables and can be used to break a continuum into its components. We review dissociations between these mechanisms and their potential role in language acquisition. We then turn to recent criticisms of the multiple mechanisms hypothesis and show that they are inconsistent with the available data. Our results suggest that artificial and natural language learning is best understood by dissecting the underlying specialized learning abilities, and that these data provide a rare opportunity to link important language phenomena to basic psychological mechanisms. For further resources related to this article, please visit the WIREs website. © 2015 Wiley Periodicals, Inc.

  15. Microscopic imaging of slow flow and diffusion: a pulsed field gradient stimulated echo sequence combined with turbo spin echo imaging

    NARCIS (Netherlands)

    Scheenen, T.W.J.; Vergeldt, F.J.; Windt, C.W.; Jager, de P.A.; As, van H.


    In this paper we present a pulse sequence that combines a displacement-encoded stimulated echo with rapid sampling of k-space by means of turbo spin echo imaging. The stimulated echo enables the use of long observation times between the two pulsed field gradients that sample q-space completely.

  16. Rapid shallow breathing (United States)

    ... the smallest air passages of the lungs in children ( bronchiolitis ) Pneumonia or other lung infection Transient tachypnea of the newborn Anxiety and panic Other serious lung disease Home Care Rapid, shallow breathing should not be treated at home. It is ...

  17. Rapid Strep Test (United States)

    ... worse than normal. Your first thoughts turn to strep throat. A rapid strep test in your doctor’s office ... your suspicions.Viruses cause most sore throats. However, strep throat is an infection caused by the Group A ...

  18. Acquisition system for the CLIC Module

    CERN Document Server

    Vilalte, Sebastien


    The status of R&D activities for CLIC module acquisition are discussed [1]. LAPP is involved in the design of the local CLIC module acquisition crate, described in the document Study of the CLIC Module Front-End Acquisition and Evaluation Electronics [2]. This acquisition system is a project based on a local crate, assigned to the CLIC module, including several mother boards. These motherboards are foreseen to hold mezzanines dedicated to the different subsystems. This system has to work in radiation environment. LAPP is involved in the development of Drive Beam stripline position monitors read-out, described in the document Drive Beam Stripline BPM Electronics and Acquisition [3]. LAPP also develops a generic acquisition mezzanine that allows to perform all-around acquisition and components tests for drive beam stripline BPM read-out.

  19. Acquisitions by EMNCs in Developed Markets

    DEFF Research Database (Denmark)

    Rabbiosi, Larissa; Elia, Stefano; Bertoni, Fabio


    Building on an organisational learning perspective, we argue that emerging market firms’ international experience and home-country characteristics are core sources of learning. Furthermore, we argue that these factors constitute important determinants of emerging market firms’ acquisition behaviour...... in developed countries (south-north acquisitions). We test our hypotheses on a sample of 808 south-north acquisitions. The acquisitions were undertaken in Europe, Japan and North America (Canada and the US) between 1999 and 2008 by firms from the emerging economies of Brazil, Russia, India and China....... As suggested by the internationalisation process model, our results show that emerging market firms undertake acquisitions in developed countries in an incremental fashion. Acquisition experience in developed markets increases the likelihood of exploitative expansion, while acquisition experience in developing...

  20. Improving Acquisition Outcomes with Contextual Ambidexterity

    DEFF Research Database (Denmark)

    Meglio, Olimpia; King, David R.; Risberg, Annette


    The results of research on mergers and acquisitions often point to a need to improve acquisition outcomes and lessen the organizational turmoil that can often follow integration efforts. We assert that viewing acquisition integration through the lens of contextual ambidexterity may improve...... acquisition outcomes in two ways: by providing an integrated solution to the economic and social tensions in acquisitions, and by enabling managers to effectively confront the competing needs of task and human integration. We also posit that by building on contextual ambidexterity, we can extend...... the possibilities for both research and practice regarding task and human integration in acquisitions. We also emphasize the role of an integration manager and integration mechanisms in enabling contextual ambidexterity for successful acquisition integration. Finally, we identify implications for research...

  1. Metagenomic covariation along densely sampled environmental gradients in the Red Sea

    KAUST Repository

    Thompson, Luke R


    Oceanic microbial diversity covaries with physicochemical parameters. Temperature, for example, explains approximately half of global variation in surface taxonomic abundance. It is unknown, however, whether covariation patterns hold over narrower parameter gradients and spatial scales, and extending to mesopelagic depths. We collected and sequenced 45 epipelagic and mesopelagic microbial metagenomes on a meridional transect through the eastern Red Sea. We asked which environmental parameters explain the most variation in relative abundances of taxonomic groups, gene ortholog groups, and pathways—at a spatial scale of <2000 km, along narrow but well-defined latitudinal and depth-dependent gradients. We also asked how microbes are adapted to gradients and extremes in irradiance, temperature, salinity, and nutrients, examining the responses of individual gene ortholog groups to these parameters. Functional and taxonomic metrics were equally well explained (75–79%) by environmental parameters. However, only functional and not taxonomic covariation patterns were conserved when comparing with an intruding water mass with different physicochemical properties. Temperature explained the most variation in each metric, followed by nitrate, chlorophyll, phosphate, and salinity. That nitrate explained more variation than phosphate suggested nitrogen limitation, consistent with low surface N:P ratios. Covariation of gene ortholog groups with environmental parameters revealed patterns of functional adaptation to the challenging Red Sea environment: high irradiance, temperature, salinity, and low nutrients. Nutrient-acquisition gene ortholog groups were anti-correlated with concentrations of their respective nutrient species, recapturing trends previously observed across much larger distances and environmental gradients. This dataset of metagenomic covariation along densely sampled environmental gradients includes online data exploration supplements, serving as a community

  2. RAPID3? Aptly named! (United States)

    Berthelot, J-M


    The RAPID3 score is the sum of three 0-10 patient self-report scores: pain, functional impairment on MDHAQ, and patient global estimate. It requires 5 seconds for scoring and can be used in all rheumatologic conditions, although it has mostly been used in rheumatoid arthritis where cutoffs for low disease activity (12/30) have been set. A RAPID3 score of ≤ 3/30 with 1 or 0 swollen joints (RAPID3 ≤ 3 + ≤ SJ1) provides remission criteria comparable to Boolean, SDAI, CDAI, and DAS28 remission criteria, in far less time than a formal joint count. RAPID3 performs as well as the DAS28 in separating active drugs from placebos in clinical trials. RAPID3 also predicts subsequent structural disease progression. RAPID3 can be determined at short intervals at home, allowing the determination of the area under the curve of disease activity between two visits and flare detection. However, RAPID3 should not be seen as a substitute for DAS28 and face to face visits in routine care. Monitoring patient status with only self-report information without a rheumatologist's advice (including joints and physical examination, and consideration of imaging and laboratory tests) may indeed be as undesirable for most patients than joint examination without a patient questionnaire. Conversely, combining the RAPID3 and the DAS28 may consist in faster or more sensitive confirmation that a medication is effective. Similarly, better enquiring of most important concerns of patients (pain, functional status and overall opinion on their disorder) should reinforces patients' confidence in their rheumatologist and treatments.

  3. Risk Taking: A Required Competency for Merger, Acquisitions, and Partnerships. (United States)

    Trepanier, Sylvain; Crenshaw, Jeannette T; Yoder-Wise, Patricia S


    Today's nurse executive is likely to find himself or herself in the middle of a merger, acquisition, and/or partnership (MAP). This is the result of health care agencies vying for market share in the midst of stiff competition, as well as decreased reimbursement in a rapidly changing payment system. The phenomenon of MAPs is fueled by the focus on care coordination and population health management. To be prepared for the ongoing and increasing MAP activity, nurse executives need to develop the skill of risk taking as an essential competency for leading change. This article emphasizes the need to maintain and improve health care quality and patient safety.

  4. Optimisation of gradient elution with serially-coupled columns. Part I: single linear gradients. (United States)

    Ortiz-Bolsico, C; Torres-Lapasió, J R; García-Alvarez-Coque, M C


    A mixture of compounds often cannot be resolved with a single chromatographic column, but the analysis can be successful using columns of different nature, serially combined through zero-dead volume junctions. In previous work (JCA 1281 (2013) 94), we developed an isocratic approach that optimised simultaneously the mobile phase composition, stationary phase nature and column length. In this work, we take the challenge of implementing optimal linear gradients for serial columns to decrease the analysis time for compounds covering a wide polarity range. For this purpose, five ACE columns of different selectivity (three C18 columns of different characteristics, a cyano and a phenyl column) were combined, aimed to resolve a mixture of 15 sulphonamides using acetonitrile-water gradients. A gradient predictive system, based on numerical integration, was built to simulate chromatograms under linear gradient profiles. Two approaches were compared: the optimisation of the combination of columns pre-selecting the gradient profile, developed by De Beer et al. (Anal. Chem. 82 (2010) 1733), and the optimisation of the gradient program after pre-selecting the column combination using isocratic elution, developed for this work. Several refinements concerning the gradient delays along the solute migration and peak half-width modelling were included to improve the realism of the predictions. Pareto plots (expressed as analysis time versus predicted global resolution) assisted in the selection of the best separation conditions. The massive computation time in the gradient optimisation, once the column combination was optimised, was reduced to ca. 3min by using genetic algorithms. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise. (United States)

    Zhang, Mingji; Or, Siu Wing


    We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME) transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG) technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME voltage between the two ME composites and is calibrated against transverse MFGs to give a high detection sensitivity of 0.4-30.6 V/(T/m), a strong common-mode magnetic field noise rejection rate of noise of 0.16-620 nT/m/ Hz in a broad frequency range of 1 Hz-170 kHz under a small baseline of 35 mm. An analysis of experimental gradient noise spectra obtained in a magnetically-unshielded laboratory environment reveals the domination of the pink (1/ f ) noise, dielectric loss noise, and power-frequency noise below 3 kHz, in addition to the circuit noise above 3 kHz, in the gradient sensor. The high detection performance, together with the added merit of passive and direct ME conversion by the large ME effect in the ME composites, makes the gradient sensor suitable for the passive, direct, and broadband detection of transverse MFGs.

  6. Gradient waveform pre-emphasis based on the gradient system transfer function. (United States)

    Stich, Manuel; Wech, Tobias; Slawig, Anne; Ringler, Ralf; Dewdney, Andrew; Greiser, Andreas; Ruyters, Gudrun; Bley, Thorsten A; Köstler, Herbert


    The gradient system transfer function (GSTF) has been used to describe the distorted k-space trajectory for image reconstruction. The purpose of this work was to use the GSTF to determine the pre-emphasis for an undistorted gradient output and intended k-space trajectory. The GSTF of the MR system was determined using only standard MR hardware without special equipment such as field probes or a field camera. The GSTF was used for trajectory prediction in image reconstruction and for a gradient waveform pre-emphasis. As test sequences, a gradient-echo sequence with phase-encoding gradient modulation and a gradient-echo sequence with a spiral read-out trajectory were implemented and subsequently applied on a structural phantom and in vivo head measurements. Image artifacts were successfully suppressed by applying the GSTF-based pre-emphasis. Equivalent results are achieved with images acquired using GSTF-based post-correction of the trajectory as a part of image reconstruction. In contrast, the pre-emphasis approach allows reconstruction using the initially intended trajectory. The artifact suppression shown for two sequences demonstrates that the GSTF can serve for a novel pre-emphasis. A pre-emphasis based on the GSTF information can be applied to any arbitrary sequence type. © 2018 International Society for Magnetic Resonance in Medicine.

  7. Direct Instruction in Second Language Acquisition: A Critical Review of Related Literature (United States)

    Hernandez, Hjalmar Punla


    Second Language Acquisition (SLA), as a sub-discipline in applied linguistics, is rapidly growing and changing (Ellis & Shintani, 2014). As such, it has yielded stirring issues on both naturalistic and instructed settings causing reviews and/or investigations by language researchers. This paper accordingly serves as a humble attempt at…

  8. Preschool Predictors of Early Literacy Acquisition in German-Speaking Children (United States)

    Fricke, Silke; Szczerbinski, Marcin; Fox-Boyer, Annette; Stackhouse, Joy


    Phonological awareness, rapid automatized naming (RAN), letter knowledge, and oral language are all significant predictors of successful literacy acquisition in several languages. However, their relative importance is less clear and depends on language characteristics, the specific aspect of literacy assessed, and the phase of literacy…

  9. USMC acquisition strategies for cots mobile devices in the tactical environment (United States)


    capabilities technology demonstration JIE joint information environment JITC joint interoperability test command JRAC joint rapid acquisition cell JTAC...laboratory environment . Basic technological components are integrated to establish that they will work together. This is relatively “low fidelity... environment . Fidelity of breadboard technology increases significantly. The basic technological components are integrated with reasonably realistic

  10. Essays on mergers and acquisitions


    Faelten, A.I.


    “Essays on Mergers and Acquisitions" tackles some of the most prominent business challenges related to M&A activity. The Introduction examines the reasons why deals fail through well-known case studies; Chapter 1 presents a new index measuring countries M&A maturity worldwide; Chapter 2 focus on the importance of corporate governance when conducting deals in unknown territories; whilst Chapter 3 and 4 conduct research on companies’ decision to tap capital markets and their subsequent M&A acti...

  11. Software Switching for Data Acquisition

    CERN Multimedia

    CERN. Geneva; Malone, David


    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  12. The GRIFFIN data acquisition system (United States)

    Garnsworthy, A. B.; Pearson, C. J.; Bishop, D.; Shaw, B.; Smith, J. K.; Bowry, M.; Bildstein, V.; Hackman, G.; Garrett, P. E.; Linn, Y.; Martin, J.-P.; Mills, W. J.; Svensson, C. E.


    Gamma-Ray Infrastructure For Fundamental Investigations of Nuclei, GRIFFIN, is a new experimental facility for radioactive decay studies at the TRIUMF-ISAC laboratory. This article describes the details of the custom designed GRIFFIN digital data acquisition system. The features of the system that will enable high-precision half-life and branching ratio measurements with levels of uncertainty better than 0.05% are described. The system has demonstrated the ability to effectively collect signals from High-purity germanium crystals at counting rates up to 50 kHz while maintaining good energy resolution, detection efficiency and spectral quality.

  13. Employment effects of foreign acquisition

    DEFF Research Database (Denmark)

    Bandick, Roger; Karpaty, Patrik


    This paper investigates the employment effects of foreign acquisitions in acquired firms in Swedish manufacturing during the 1990s; a period characterized by a dramatic increase in foreign ownership. We find some evidence of positive employment effects in acquired firms and it seems...... that the employment of skilled labor increasesmore than that of less-skilled labor. Our results indicate that the positive employment effects are more pronounced in acquired non-MNEs than in Swedish MNEs. Furthermore, we observe shifts in skill intensities toward higher shares of skilled labor in non-MNEs taken over...

  14. Negotiating optimum capital equipment acquisitions. (United States)

    Pols, A L


    Healthcare organizations planning capital equipment acquisitions should negotiate with more than one equipment vendor and determine the equipment purchase price, service agreement price, and financing or leasing option rate separately to avoid hidden costs. The purchase price should be negotiated first. A long-term service agreement should be locked in, or service insurance purchased, for the length of the financing or lease agreement. The equipment vendor's financing agreement should be compared with offers from third parties, who may have more beneficial financing options or more flexible lease arrangements.

  15. Control and acquisition software complex for TBTS experiments

    CERN Document Server

    Dubrovskiy, Alexey


    The Two-beam Test-stand (TBTS) is a test area in the CLIC Test Facility (CTF3) to demonstrate the high power RF extraction and acceleration at a high accelerating gradient, which are feasibility issues for the Compact Linear Collider (CLIC) project. In order to achieve an efficient data collection, an acquisition and logging software system was developed. All year round these systems store the main parameters such as beam position, beam current, vacuum level, pulse length etc. For predefined events they also gather and store all information about the last several pulses and the machine status. A GUI interface allows from anywhere to plot many logged characteristics at a maximum of 10 minutes delay, to go though all events and to extract any logged data. A control interface configures actions and long-term control procedures for conditioning accelerating structures. The flexible configuration of the logging, the acquisition and the control systems are integrated into the same GUI. After two years operation the...

  16. Entanglement-Gradient Routing for Quantum Networks. (United States)

    Gyongyosi, Laszlo; Imre, Sandor


    We define the entanglement-gradient routing scheme for quantum repeater networks. The routing framework fuses the fundamentals of swarm intelligence and quantum Shannon theory. Swarm intelligence provides nature-inspired solutions for problem solving. Motivated by models of social insect behavior, the routing is performed using parallel threads to determine the shortest path via the entanglement gradient coefficient, which describes the feasibility of the entangled links and paths of the network. The routing metrics are derived from the characteristics of entanglement transmission and relevant measures of entanglement distribution in quantum networks. The method allows a moderate complexity decentralized routing in quantum repeater networks. The results can be applied in experimental quantum networking, future quantum Internet, and long-distance quantum communications.

  17. Bioactive Molecule Prediction Using Extreme Gradient Boosting. (United States)

    Babajide Mustapha, Ismail; Saeed, Faisal


    Following the explosive growth in chemical and biological data, the shift from traditional methods of drug discovery to computer-aided means has made data mining and machine learning methods integral parts of today's drug discovery process. In this paper, extreme gradient boosting (Xgboost), which is an ensemble of Classification and Regression Tree (CART) and a variant of the Gradient Boosting Machine, was investigated for the prediction of biological activity based on quantitative description of the compound's molecular structure. Seven datasets, well known in the literature were used in this paper and experimental results show that Xgboost can outperform machine learning algorithms like Random Forest (RF), Support Vector Machines (LSVM), Radial Basis Function Neural Network (RBFN) and Naïve Bayes (NB) for the prediction of biological activities. In addition to its ability to detect minority activity classes in highly imbalanced datasets, it showed remarkable performance on both high and low diversity datasets.

  18. Subduction zones seen by GOCE gravity gradients

    DEFF Research Database (Denmark)

    Švarc, Mario; Herceg, Matija; Cammarano, Fabio

    In this study, the GOCE (Gravity field and steady state Ocean Circulation Explorer) gradiometry data were used to study geologic structures and mass variations within the lithosphere in areas of known subduction zones. The advantage of gravity gradiometry over other gravity methods...... is that gradients are extremely sensitive to localized density contrasts within regional geological settings, which makes it ideally suited for detecting subduction zones. Second order gravity gradients of disturbing potential were extracted from global geopotential model, the fifth release GOCE model ‘EGM_TIM_RL05......’. In order to remove the signal which mainly corresponds to the gravity signal of the lower mantle, long wavelength part of the gravity signal was removed up to degree and order 60. Because the areas with notable topography differences coincide with subduction zones, topography correction was also performed...

  19. Sequential pattern formation governed by signaling gradients

    CERN Document Server

    Jörg, David J; Jülicher, Frank


    Rhythmic and sequential segmentation of the embryonic body plan is a vital developmental patterning process in all vertebrate species. However, a theoretical framework capturing the emergence of dynamic patterns of gene expression from the interplay of cell oscillations with tissue elongation and shortening and with signaling gradients, is still missing. Here we show that a set of coupled genetic oscillators in an elongating tissue that is regulated by diffusing and advected signaling molecules can account for segmentation as a self-organized patterning process. This system can form a finite number of segments and the dynamics of segmentation and the total number of segments formed depend strongly on kinetic parameters describing tissue elongation and signaling molecules. The model accounts for existing experimental perturbations to signaling gradients, and makes testable predictions about novel perturbations. The variety of different patterns formed in our model can account for the variability of segmentatio...

  20. Functional evolution of a morphogenetic gradient. (United States)

    Kwan, Chun Wai; Gavin-Smyth, Jackie; Ferguson, Edwin L; Schmidt-Ott, Urs


    Bone Morphogenetic Proteins (BMPs) pattern the dorsal-ventral axis of bilaterian embryos; however, their roles in the evolution of body plan are largely unknown. We examined their functional evolution in fly embryos. BMP signaling specifies two extraembryonic tissues, the serosa and amnion, in basal-branching flies such as Megaselia abdita, but only one, the amnioserosa, in Drosophila melanogaster. The BMP signaling dynamics are similar in both species until the beginning of gastrulation, when BMP signaling broadens and intensifies at the edge of the germ rudiment in Megaselia, while remaining static in Drosophila. Here we show that the differences in gradient dynamics and tissue specification result from evolutionary changes in the gene regulatory network that controls the activity of a positive feedback circuit on BMP signaling, involving the tumor necrosis factor alpha homolog eiger. These data illustrate an evolutionary mechanism by which spatiotemporal changes in morphogen gradients can guide tissue complexity.

  1. Analytic gradients in electronic structure theory (United States)

    Shroll, Robert Marvin


    The energy gradients for the Hartree Fock ground state, Dirac-Hartree-Fock ground state, singles-only configuration interaction approximation to the first singlet excited state, and a set of restricted singles- only configuration interaction equations are presented. Algebraic approximations will be used in all of these state energy equation derivations. This leads us to a commonality between the various methods which is the need to calculate gradients with respect to basis set expansion coefficients. For the non-relativistic correlated energy states, these coefficient derivatives will be determined using Coupled Perturbed Hartree Fock (CPHF) theory. For the relativistic case, an analogous set of equations are presented which have been called the Coupled Perturbed Dirac-Hartree-Fock (CPDHF) equations.

  2. Examining the education gradient in chronic illness


    Chatterji, Pinka; Joo, Heesoo; Lahiri, Kajal


    This study examines the education gradient in three chronic conditions – diabetes, hypertension, and high cholesterol. In the analysis, we take into account diagnosed as well as undiagnosed cases, and we use methods that account for the possibility that unmeasured factors exist that are correlated with education and drive both the likelihood of having the illness and the propensity to be diagnosed with illness if it exists. Data come from the National Health and Nutrition Examination Survey (...

  3. Conjugate gradient optimization programs for shuttle reentry (United States)

    Powers, W. F.; Jacobson, R. A.; Leonard, D. A.


    Two computer programs for shuttle reentry trajectory optimization are listed and described. Both programs use the conjugate gradient method as the optimization procedure. The Phase 1 Program is developed in cartesian coordinates for a rotating spherical earth, and crossrange, downrange, maximum deceleration, total heating, and terminal speed, altitude, and flight path angle are included in the performance index. The programs make extensive use of subroutines so that they may be easily adapted to other atmospheric trajectory optimization problems.

  4. M-step preconditioned conjugate gradient methods (United States)

    Adams, L.


    Preconditioned conjugate gradient methods for solving sparse symmetric and positive finite systems of linear equations are described. Necessary and sufficient conditions are given for when these preconditioners can be used and an analysis of their effectiveness is given. Efficient computer implementations of these methods are discussed and results on the CYBER 203 and the Finite Element Machine under construction at NASA Langley Research Center are included.

  5. Intergenerational and socioeconomic gradients of childhood obesity


    Joan Costa-i-Font; Joan Gil


    Can the rise in obesity among children be attributed to intergenerationally parental influences? How important is a parent’s socioeconomic status in accounting for the emergence of obesity among children? This paper documents evidence of an emerging social gradient of obesity in pre-school children resulting from a combination of income and education effects, as well as less intensive childcare associated with maternal employment, when different forms of intergenerational transmission are con...

  6. Designing optimal nanofocusing with a gradient hyperlens (United States)

    Shen, Lian; Prokopeva, Ludmila J.; Chen, Hongsheng; Kildishev, Alexander V.


    We report the design of a high-throughput gradient hyperbolic lenslet built with real-life materials and capable of focusing a beam into a deep sub-wavelength spot of λ/23. This efficient design is achieved through high-order transformation optics and circular effective-medium theory (CEMT), which are used to engineer the radially varying anisotropic artificial material based on the thin alternating cylindrical metal and dielectric layers. The radial gradient of the effective anisotropic optical constants allows for matching the impedances at the input and output interfaces, drastically improving the throughput of the lenslet. However, it is the use of the zeroth-order CEMT that enables the practical realization of a gradient hyperlens with realistic materials. To illustrate the importance of using the CEMT versus the conventional planar effective-medium theory (PEMT) for cylindrical anisotropic systems, such as our hyperlens, both the CEMT and PEMT are adopted to design gradient hyperlenses with the same materials and order of elemental layers. The CEMT- and PEMT-based designs show similar performance if the number of metal-dielectric binary layers is sufficiently large (9+ pairs) and if the layers are sufficiently thin. However, for the manufacturable lenses with realistic numbers of layers (e.g. five pairs) and thicknesses, the performance of the CEMT design continues to be practical, whereas the PEMT-based design stops working altogether. The accurate design of transformation optics-based layered cylindrical devices enabled by CEMT allow for a new class of robustly manufacturable nanophotonic systems, even with relatively thick layers of real-life materials.

  7. Fracture driven by a Thermal Gradient

    CERN Document Server

    Pla, O


    Motivated by recent experiments by Yuse and Sano (Nature, 362, 329 (1993)), we propose a discrete model of linear springs for studying fracture in thin and elastically isotropic brittle films. The method enables us to draw a map of the stresses in the material. Cracks generated by the model, imposing a moving thermal gradient in the material, can branch or wiggle depending on the driving parameters. The results may be used to compare with other recent theoretical work, or to design future experiments.

  8. Advanced concepts for high-gradient acceleration

    Energy Technology Data Exchange (ETDEWEB)

    Whittum, D.H.


    The promise of high-gradient accelerator research is a future for physics beyond the 5-TeV energy scale. Looking beyond what can be engineered today, the authors examine basic research directions for colliders of the future, from mm-waves to lasers, and from solid-state to plasmas, with attention to material damage, beam-dynamics, a workable collision scheme, and energetics.

  9. Velocity Gradient Power Functional for Brownian Dynamics. (United States)

    de Las Heras, Daniel; Schmidt, Matthias


    We present an explicit and simple approximation for the superadiabatic excess (over ideal gas) free power functional, admitting the study of the nonequilibrium dynamics of overdamped Brownian many-body systems. The functional depends on the local velocity gradient and is systematically obtained from treating the microscopic stress distribution as a conjugate field. The resulting superadiabatic forces are beyond dynamical density functional theory and are of a viscous nature. Their high accuracy is demonstrated by comparison to simulation results.

  10. Self-organization of intracellular gradients during mitosis

    Directory of Open Access Journals (Sweden)

    Fuller Brian G


    Full Text Available Abstract Gradients are used in a number of biological systems to transmit spatial information over a range of distances. The best studied are morphogen gradients where information is transmitted over many cell lengths. Smaller mitotic gradients reflect the need to organize several distinct events along the length of the mitotic spindle. The intracellular gradients that characterize mitosis are emerging as important regulatory paradigms. Intracellular gradients utilize intrinsic auto-regulatory feedback loops and diffusion to establish stable regions of activity within the mitotic cytosol. We review three recently described intracellular mitotic gradients. The Ran GTP gradient with its elaborate cascade of nuclear transport receptors and cargoes is the best characterized, yet the dynamics underlying the robust gradient of Ran-GTP have received little attention. Gradients of phosphorylation have been observed on Aurora B kinase substrates both before and after anaphase onset. In both instances the phosphorylation gradient appears to result from a soluble gradient of Aurora B kinase activity. Regulatory properties that support gradient formation are highlighted. Intracellular activity gradients that regulate localized mitotic events bare several hallmarks of self-organizing biologic systems that designate spatial information during pattern formation. Intracellular pattern formation represents a new paradigm in mitotic regulation.

  11. Seabed morphology and sedimentary processes on high-gradient trough mouth fans offshore Troms, northern Norway (United States)

    Rydningen, Tom Arne; Laberg, Jan Sverre; Kolstad, Vidar


    slope of these TMFs promoted rapid transformation from small-scale slumps and debris flows on the upper slope, into partly erosive turbidity currents. These flows continued into the deep sea, thus promoting efficient sediment by-pass across the TMFs. This model can be applied to other TMFs situated at the mouths of other glaciated cross-shelf troughs. In contrast, low-gradient TMFs are found to be dominated by glacigenic debris flow deposits. Furthermore, gully-channel complexes demonstrating the presence of erosive turbidity currents on high-gradient TMFs are rare on low-gradient TMFs. Large submarine landslides occur at both high- and low-gradient TMFs.

  12. Gradient field microscopy of unstained specimens (United States)

    Kim, Taewoo; Sridharan, Shamira; Popescu, Gabriel


    We present a phase derivative microscopy technique referred to as gradient field microscopy (GFM), which provides the first-order derivatives of the phase associated with an optical field passing through a transparent specimen. GFM utilizes spatial light modulation at the Fourier plane of a bright field microscope to optically obtain the derivatives of the phase and increase the contrast of the final image. The controllable spatial modulation pattern allows us to obtain both one component of the field gradient (derivative along one direction) and the gradient intensity, which offers some advantages over the regular differential interference contrast (DIC) microscopy. Most importantly, unlike DIC, GFM does not use polarizing optics and, thus, it is applicable to birefringent samples. We demonstrate these features of GFM with studies of static and dynamic biological cells (HeLa cells and red blood cells). We show that GFM is capable of qualitatively providing information about cell membrane fluctuations. Specifically, we captured the disappearance of the bending mode of fluctuations in osmotically swollen red blood cells. PMID:22418558

  13. Air temperature gradient in large industrial hall (United States)

    Karpuk, Michał; Pełech, Aleksander; Przydróżny, Edward; Walaszczyk, Juliusz; Szczęśniak, Sylwia


    In the rooms with dominant sensible heat load, volume airflow depends on many factors incl. pre-established temperature difference between exhaust and supply airflow. As the temperature difference is getting higher, airflow volume drops down, consequently, the cost of AHU is reduced. In high industrial halls with air exhaust grids located under the ceiling additional temperature gradient above working zone should be taken into consideration. In this regard, experimental research of the vertical air temperature gradient in high industrial halls were carried out for the case of mixing ventilation system The paper presents the results of air temperature distribution measurements in high technological hall (mechanically ventilated) under significant sensible heat load conditions. The supply airflow was delivered to the hall with the help of the swirl diffusers while exhaust grids were located under the hall ceiling. Basing on the air temperature distribution measurements performed on the seven pre-established levels, air temperature gradient in the area between 2.0 and 7.0 m above the floor was calculated and analysed.

  14. High-thermal-gradient Superalloy Crystal Growth (United States)

    Pearson, D. D.; Anton, D. L.; Giamei, A. F.


    Single, (001)-oriented crystals of PWA 1480 were processed in alumina/silica shell molds in a laboratory high gradient furnace. The furnace employs a graphite resistance heated element, a radiation baffle, and a water cooled radiation trap below the baffle. All crystals were grown in vacuum (10 torr) and all heat transfer was radiative. The element is constructed with a variable cross section that is tapered just above the baffle to maximize heat input and therefore thermal gradient. A maximum alloy temperature of 1600 C was used. A thermal gradient of 130 deg C/cm was recorded at 1370 C just above the solidus of the PWA 1480 alloys. Crystal bars with 14.4 and 17.5 mm diameters were grown in alumina/silica shell molds. Each crystal was started from a 1.6 mm pencil seed at a rate of 76 mm/hr and slowly accelerated to a rate of 200 mm/hr under computer control. Volume percent porosity and average pore size were measured as functions of distance in representative bars. Low cycle fatigue behavior and stress rupture properties were determined.

  15. Theories of early language acquisition. (United States)

    Plunkett, K


    What features of brain processing and neural development support linguistic development in young children? To what extent is the profile and timing of linguistic development in young children determined by a pre-ordained genetic programme? Does the environment play a crucial role in determining the patterns of change observed in children growing up? Recent experimental, neuroimaging and computational studies of developmental change in children promise to contribute to a deeper understanding of how the brain becomes wired up for language. In this review, the muttidisciplinary perspectives of cognitive neuroscience, experimental psycholinguistics and neural network modelling are brought to bear on four distinct areas in the study of language acquisition: early speech perception, word recognition, word learning and the acquisition of grammatical inflections. It is suggested that each area demonstrates how linguistic development can be driven by the interaction of general learning mechanisms, highly sensitive to particular statistical regularities in the input, with a richly structured environment which provides the necessary ingredients for the emergence of linguistic representations that support mature language processing. Similar epigenetic principles, guiding the emergence of linguistic structure, apply to all these domains, offering insights into phenomena ranging from the precocity of young infant's sensitivity to speech contrasts to the complexities of the problem facing the young child learning the arabic plural.

  16. Rotary Percussive Sample Acquisition Tool (United States)

    Klein, K.; Badescu, M.; Haddad, N.; Shiraishi, L.; Walkemeyer, P.


    As part of a potential Mars Sample Return campaign NASA is studying a sample caching mission to Mars, with a possible 2018 launch opportunity. As such, a Sample Acquisition Tool (SAT) has been developed in support of the Integrated Mars Sample Acquisition and Handling (IMSAH) architecture as it relates to the proposed Mars Sample Return (MSR) campaign. The tool allows for core generation and capture directly into a sample tube. In doing so, the sample tube becomes the fundamental handling element within the IMSAH sample chain reducing the risk associated with sample contamination as well as the need to handle a sample of unknown geometry. The tool's functionality was verified utilizing a proposed rock test suite that encompasses a series of rock types that have been utilized in the past to qualify Martian surface sampling hardware. The corresponding results have shown the tool can effectively generate, fracture, and capture rock cores while maintaining torque margins of no less than 50% with an average power consumption of no greater than 90W and a tool mass of less than 6kg.

  17. The adaptation rate of a quantitative trait in an environmental gradient (United States)

    Hermsen, R.


    The spatial range of a species habitat is generally determined by the ability of the species to cope with biotic and abiotic variables that vary in space. Therefore, the species range is itself an evolvable property. Indeed, environmental gradients permit a mode of evolution in which range expansion and adaptation go hand in hand. This process can contribute to rapid evolution of drug resistant bacteria and viruses, because drug concentrations in humans and livestock treated with antibiotics are far from uniform. Here, we use a minimal stochastic model of discrete, interacting organisms evolving in continuous space to study how the rate of adaptation of a quantitative trait depends on the steepness of the gradient and various population parameters. We discuss analytical results for the mean-field limit as well as extensive stochastic simulations. These simulations were performed using an exact, event-driven simulation scheme that can deal with continuous time-, density- and coordinate-dependent reaction rates and could be used for a wide variety of stochastic systems. The results reveal two qualitative regimes. If the gradient is shallow, the rate of adaptation is limited by dispersion and increases linearly with the gradient slope. If the gradient is steep, the adaptation rate is limited by mutation. In this regime, the mean-field result is highly misleading: it predicts that the adaptation rate continues to increase with the gradient slope, whereas stochastic simulations show that it in fact decreases with the square root of the slope. This discrepancy underscores the importance of discreteness and stochasticity even at high population densities; mean-field results, including those routinely used in quantitative genetics, should be interpreted with care.

  18. Technical note: Development of a gradient tube method for ...

    African Journals Online (AJOL)

    Technical note: Development of a gradient tube method for examining microbial population structures in floating sulphur biofilms. ... parameters within the system. Keywords: gradient tube method, floating biofilms, floating sulphur biofilms, microbial ecology, sulphur biotechnology, acid mine drainage wastewaters ...

  19. Integrated gravity and gravity gradient 3D inversion using the non-linear conjugate gradient (United States)

    Qin, Pengbo; Huang, Danian; Yuan, Yuan; Geng, Meixia; Liu, Jie


    Gravity data, which are critical in mineral, oil, and gas exploration, are obtained from the vertical component of the gravity field, while gravity gradient data are measured from changes in the gravity field in three directions. However, few studies have sought to improve exploration techniques by integrating gravity and gravity gradient data using inversion methods. In this study, we developed a new method to integrate gravity and gravity gradient data in a 3D density inversion using the non-linear conjugate gradient (NLCG) method and the minimum gradient support (MGS) functional to regularize the 3D inverse problem and to obtain a clear and accurate image of the anomalous body. The NLCG algorithm, which is suitable for solving large-scale nonlinear optimization problems and requires no memory storage, was compared to the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton algorithm and the results indicated that the convergence rate of NLCG is slower, but that the storage requirement and computation time is lower. To counteract the decay in kernel function, we introduced a depth weighting function for anomalous bodies at the same depth, with information about anomalous body depth obtained from well log and seismic exploration data. For anomalous bodies at different depths, we introduced a spatial gradient weighting function to incorporate additional information obtained in the inversion. We concluded that the spatial gradient weighting function enhanced the spatial resolution of the recovered model. Furthermore, our results showed that including multiple components for inversion increased the resolution of the recovered model. We validated our model by applying our inversion method to survey data from Vinton salt dome, Louisiana, USA. The results showed good agreement with known geologic information; thus confirming the accuracy of this approach.

  20. Magnetoelectric Transverse Gradient Sensor with High Detection Sensitivity and Low Gradient Noise

    Directory of Open Access Journals (Sweden)

    Mingji Zhang


    Full Text Available We report, theoretically and experimentally, the realization of a high detection performance in a novel magnetoelectric (ME transverse gradient sensor based on the large ME effect and the magnetic field gradient (MFG technique in a pair of magnetically-biased, electrically-shielded, and mechanically-enclosed ME composites having a transverse orientation and an axial separation. The output voltage of the gradient sensor is directly obtained from the transverse MFG-induced difference in ME voltage between the two ME composites and is calibrated against transverse MFGs to give a high detection sensitivity of 0.4–30.6 V/(T/m, a strong common-mode magnetic field noise rejection rate of <−14.5 dB, a small input-output nonlinearity of <10 ppm, and a low gradient noise of 0.16–620 nT/m/ Hz in a broad frequency range of 1 Hz–170 kHz under a small baseline of 35 mm. An analysis of experimental gradient noise spectra obtained in a magnetically-unshielded laboratory environment reveals the domination of the pink (1/f noise, dielectric loss noise, and power-frequency noise below 3 kHz, in addition to the circuit noise above 3 kHz, in the gradient sensor. The high detection performance, together with the added merit of passive and direct ME conversion by the large ME effect in the ME composites, makes the gradient sensor suitable for the passive, direct, and broadband detection of transverse MFGs.

  1. Comparing species interaction networks along environmental gradients. (United States)

    Pellissier, Loïc; Albouy, Camille; Bascompte, Jordi; Farwig, Nina; Graham, Catherine; Loreau, Michel; Maglianesi, Maria Alejandra; Melián, Carlos J; Pitteloud, Camille; Roslin, Tomas; Rohr, Rudolf; Saavedra, Serguei; Thuiller, Wilfried; Woodward, Guy; Zimmermann, Niklaus E; Gravel, Dominique


    Knowledge of species composition and their interactions, in the form of interaction networks, is required to understand processes shaping their distribution over time and space. As such, comparing ecological networks along environmental gradients represents a promising new research avenue to understand the organization of life. Variation in the position and intensity of links within networks along environmental gradients may be driven by turnover in species composition, by variation in species abundances and by abiotic influences on species interactions. While investigating changes in species composition has a long tradition, so far only a limited number of studies have examined changes in species interactions between networks, often with differing approaches. Here, we review studies investigating variation in network structures along environmental gradients, highlighting how methodological decisions about standardization can influence their conclusions. Due to their complexity, variation among ecological networks is frequently studied using properties that summarize the distribution or topology of interactions such as number of links, connectance, or modularity. These properties can either be compared directly or using a procedure of standardization. While measures of network structure can be directly related to changes along environmental gradients, standardization is frequently used to facilitate interpretation of variation in network properties by controlling for some co-variables, or via null models. Null models allow comparing the deviation of empirical networks from random expectations and are expected to provide a more mechanistic understanding of the factors shaping ecological networks when they are coupled with functional traits. As an illustration, we compare approaches to quantify the role of trait matching in driving the structure of plant-hummingbird mutualistic networks, i.e. a direct comparison, standardized by null models and hypothesis

  2. Rapid small lot manufacturing

    Energy Technology Data Exchange (ETDEWEB)

    Harrigan, R.W.


    The direct connection of information, captured in forms such as CAD databases, to the factory floor is enabling a revolution in manufacturing. Rapid response to very dynamic market conditions is becoming the norm rather than the exception. In order to provide economical rapid fabrication of small numbers of variable products, one must design with manufacturing constraints in mind. In addition, flexible manufacturing systems must be programmed automatically to reduce the time for product change over in the factory and eliminate human errors. Sensor based machine control is needed to adapt idealized, model based machine programs to uncontrolled variables such as the condition of raw materials and fabrication tolerances.

  3. Data acquisition with direct memory access

    Directory of Open Access Journals (Sweden)

    Iu. Guzun


    Full Text Available This paper is concerned about using Direct Memory Access (DMA transfer for real-time data acquisitions from a plug-in data acquisition board Aquarius DSP-1. Since the conversion speed of the modern Analog to Digital Converters is increasevealy, the using of the interrupts for reading of the conversion results becomes impossible. For the data acquisition system, presented in this paper, this speed is up to 100 kS/s. This problem can be successfully solved using DMA technique. We subsequently describe the hardware of the data acquisition board, which has been used to acquire data. Next, have been presented the functions, in C programming language, for programming a data acquisition via DMA. Finally, we present some results obtained using this kind of data acquisitions, and some conclusions.

  4. Controllable Soluble Protein Concentration Gradients in Hydrogel Networks**


    Peret, Brian J.; William L Murphy


    Here we report controlled formation of sustained, soluble protein concentration gradients within hydrated polymer networks. The approach involves spatially localizing proteins or biodegradable, protein-loaded microspheres within hydrogels to form a protein-releasing “depot”. Soluble protein concentration gradients are then formed as the released protein diffuses away from the localized source. Control over key gradient parameters, including maximum concentration, gradient magnitude, slope, an...

  5. Rapid Cycling and Its Treatment (United States)

    ... Announcements Public Service Announcements Partnering with DBSA Rapid Cycling and its Treatment What is bipolar disorder? Bipolar ... to Depression and Manic Depression . What is rapid cycling? Rapid cycling is defined as four or more ...

  6. Change Management in Mergers and Acquisitions


    Paul, Karnica


    More and more firms are looking at Mergers and Acquisitions as a relatively fast and efficient way to expand into new markets and incorporate new technologies. From a strategic point of view, Mergers and Acquisitions are thought to strengthen and sustain their position in the market place. Still this strategy’s success is by no means assured. On the contrary, a majority of these Mergers & Acquisitions fall short of their confirmed goals and objectives. Some failures can be explained by financ...

  7. Maximising Firm Value through Mergers and Acquisitions


    Lon, Wai See


    Mergers and acquisitions, literally, are centred on the objective to create economic value for firms and shareholders. Different mergers and acquisitions strategies would affect the extent of shareholder value. This study seeks to examine the value implications of mergers and acquisitions by studying shareholder value creation for a 60 Malaysian firms which have been actively involved in the cross-border and domestic diversifications during the period 1996 – 2004.Our focus in this study is to...

  8. Mergers and acquisitions : The road to success


    Hulthén, Andreas; Selguson, Kim


    Background: The most common reason to mergers and acquisitions is to generate synergies. Synergies emerge when two collaborating companies show a better result together than they would have done separately. Even though mergers and acquisitions have taken place since the beginning of the 17th century many of them still fail to succeed. There are many reasons why. Despite the fact that the reasons of failure have been known for a long time, new waves of mergers and acquisitions still appear. P...

  9. Salinity Gradient Energy: Current State and New Trends

    Directory of Open Access Journals (Sweden)

    Olivier Schaetzle


    Full Text Available In this article we give an overview of the state of the art of salinity gradient technologies. We first introduce the concept of salinity gradient energy, before describing the current state of development of the most advanced of these technologies. We conclude with the new trends in the young field of salinity gradient technologies.

  10. Gradient Descent Bit Flipping Algorithms for Decoding LDPC Codes


    Wadayama, Tadashi; Nakamura, Keisuke; Yagita, Masayuki; Funahashi, Yuuki; Usami, Shogo; Takumi, Ichi


    A novel class of bit-flipping (BF) algorithms for decoding low-density parity-check (LDPC) codes is presented. The proposed algorithms, which are called gradient descent bit flipping (GDBF) algorithms, can be regarded as simplified gradient descent algorithms. Based on gradient descent formulation, the proposed algorithms are naturally derived from a simple non-linear objective function.

  11. Acquired Inventors’ Productivity after Horizontal Acquisition

    DEFF Research Database (Denmark)

    Colombo, Massimo G.; Moreira, Solon; Rabbiosi, Larissa

    Effective integration of the R&D functions of the acquired and acquiring firms is essential for knowledge recombination after acquisition. However, prior research suggests that the post-acquisition integration process often damages the inventive labor force. We argue that an examination of the mu......Effective integration of the R&D functions of the acquired and acquiring firms is essential for knowledge recombination after acquisition. However, prior research suggests that the post-acquisition integration process often damages the inventive labor force. We argue that an examination...

  12. Consumption Skill Acquisition in Ski Schools

    DEFF Research Database (Denmark)

    Woermann, Niklas; Wieser, Verena


    Remedying the absence of a cultural theory of consumption skill acquisition, we use video data to explore how consumers learn in ski schools. We identify six modes of skill acquisition and theorize the interplay between the sensori-motor system, the conscious state of skillful coping, and the soc......Remedying the absence of a cultural theory of consumption skill acquisition, we use video data to explore how consumers learn in ski schools. We identify six modes of skill acquisition and theorize the interplay between the sensori-motor system, the conscious state of skillful coping...

  13. Acquisition in different and special subject areas

    CERN Document Server

    Katz, Linda S


    Learn how acquisitions librarians successfully serve specialized users! In this book, you'll find profiles, methods, and processes for acquisitions in specialized subject areas, such as local and regional poetry, oceanography, educational information in electronic formats, popular fiction, regional and ethnic materials, and more. Seasoned acquisitions librarians share their experiences in gathering the hard-to-find materials their libraries' highly specialized clients need to access. You'll also examine issues surrounding the acquisition of new reference tools that are vital in today's emergi

  14. Validating Acquisition IS Integration Readiness with Drills

    DEFF Research Database (Denmark)

    Wynne, Peter J.


    To companies, mergers and acquisitions are important strategic tools, yet they often fail to deliver their expected value. Studies have shown the integration of information systems is a significant roadblock to the realisation of acquisition benefits, and for an IT department to be ready......), to understand how an IT department can use them to validate their integration plans. The paper presents a case study of two drills used to validate an IT department’s readiness to carry out acquisition IS integration, and suggests seven acquisition IS integration drill characteristics others could utilise when...

  15. Rapid manufacturing for microfluidics

    CSIR Research Space (South Africa)

    Land, K


    Full Text Available . Microfluidics is at the forefront of developing solutions for drug discovery, diagnostics (from glucose tests to malaria and TB testing) and environmental diagnostics (E-coli monitoring of drinking water). In order to quickly implement new designs, a rapid...

  16. Rapid Prototyping in PVS (United States)

    Munoz, Cesar A.; Butler, Ricky (Technical Monitor)


    PVSio is a conservative extension to the PVS prelude library that provides basic input/output capabilities to the PVS ground evaluator. It supports rapid prototyping in PVS by enhancing the specification language with built-in constructs for string manipulation, floating point arithmetic, and input/output operations.

  17. Rapid Prototyping Reconsidered (United States)

    Desrosier, James


    Continuing educators need additional strategies for developing new programming that can both reduce the time to market and lower the cost of development. Rapid prototyping, a time-compression technique adapted from the high technology industry, represents one such strategy that merits renewed evaluation. Although in higher education rapid…

  18. Hematoma volume measurement in gradient echo MRI using quantitative susceptibility mapping. (United States)

    Wang, Shuo; Lou, Min; Liu, Tian; Cui, Deqi; Chen, Xiaomei; Wang, Yi


    A novel quantitative susceptibility mapping (QSM) processing technology has been developed to map tissue susceptibility property without blooming artifacts. We hypothesize that hematoma volume measurement on QSM is independent of imaging parameters, eliminating its echo time dependence on gradient echo MRI. Gradient echo MRI of 16 patients with intracerebral hemorrhage was processed with susceptibility-weighted imaging, R2* (=1/T2*) mapping, and QSM at various echo times. Hematoma volumes were measured from these images. Linear regression of hematoma volume versus echo time showed substantial slopes for gradient echo magnitude (0.45±0.31 L/s), susceptibility-weighted imaging (0.52±0.46), and R2* (0.39±0.30) but nearly zero slope for QSM (0.01±0.05). At echo time=20 ms, hematoma volume on QSM was 0.80× that on gradient echo magnitude image (R2=0.99). QSM can provide reliable measurement of hematoma volume, which can be performed rapidly and accurately using a semiautomated segmentation tool.

  19. Temporal Changes in Education Gradients of ‘Preventable’ Mortality: A Test of Fundamental Cause Theory (United States)

    Masters, Ryan K.; Link, Bruce G.; Phelan, Jo C.


    Fundamental cause theory explains persisting associations between socioeconomic status and mortality in terms of personal resources such as knowledge, money, power, prestige, and social connections, as well as disparate social contexts related to these resources. We review evidence concerning fundamental cause theory and test three central claims using the National Health Interview Survey Linked Mortality Files 1986-2004. We then examine cohort-based variation in the associations between a fundamental social cause of disease, educational attainment, and mortality rates from heart disease, other “preventable” causes of death, and less preventable causes of death. We further explore race/ethnic and gender variation in these associations. Overall, findings are consistent with nearly all features of fundamental cause theory. Results show, first, larger education gradients in mortality risk for causes of death that are under greater human control than for less preventable causes of death, and, second, that these gradients grew more rapidly across successive cohorts than gradients for less preventable causes. Results also show that relative sizes and cohort-based changes in the education gradients vary substantially by race/ethnicity and gender. PMID:25556675

  20. Trends in education gradients of 'preventable' mortality: a test of fundamental cause theory. (United States)

    Masters, Ryan K; Link, Bruce G; Phelan, Jo C


    Fundamental cause theory explains persisting associations between socioeconomic status and mortality in terms of personal resources such as knowledge, money, power, prestige, and social connections, as well as disparate social contexts related to these resources. We review evidence concerning fundamental cause theory and test three central claims using the National Health Interview Survey Linked Mortality Files 1986-2004. We then examine cohort-based variation in the associations between a fundamental social cause of disease, educational attainment, and mortality rates from heart disease, other "preventable" causes of death, and less preventable causes of death. We further explore race/ethnic and gender variation in these associations. Overall, findings are consistent with nearly all features of fundamental cause theory. Results show, first, larger education gradients in mortality risk for causes of death that are under greater human control than for less preventable causes of death, and, second, that these gradients grew more rapidly across successive cohorts than gradients for less preventable causes. Results also show that relative sizes and cohort-based changes in the education gradients vary substantially by race/ethnicity and gender. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Customised spatiotemporal temperature gradients created by a liquid metal enabled vortex generator. (United States)

    Zhu, Jiu Yang; Thurgood, Peter; Nguyen, Ngan; Ghorbani, Kamran; Khoshmanesh, Khashayar


    Generating customised temperature gradients in miniaturised flow-free liquid chambers is challenging due to the dominance of diffusion. Inducing internal flows in the form of vortices is an effective strategy for overcoming the limitations of diffusion in such environments. Vortices can be produced by applying pressure, temperature and electric potential gradients via miniaturised actuators. However, the difficulties associated with the fabrication, integration, maintenance and operation of such actuators hinder their utility. Here, we utilise liquid metal enabled pumps to induce vortices inside a miniaturised liquid chamber. The configuration and rotational velocity of these vortices can be controlled by tuning the polarity and frequency of the energising electrical signal. This allows creation of customised spatial temperature gradients inside the chamber. The absence of conventional moving elements in the pumps facilitates the rapid reconfiguration of vortices. This enables quick transition from one temperature profile to another, and creates customised spatiotemporal temperature gradients. This allows temperature oscillation from 35 to 62 °C at the hot spot, and from 25 to 27 °C at the centre of the vortex within 15 seconds. Our liquid metal enabled vortex generator can be fabricated, integrated and operated easily, and offers opportunities for studying thermo-responsive materials and biological samples.

  2. Electric vehicle data acquisition system

    DEFF Research Database (Denmark)

    Svendsen, Mathias; Winther-Jensen, Mads; Pedersen, Anders Bro


    A data acquisition system for electric vehicles is presented. The system connects to the On-board Diagnostic port of newer vehicles, and utilizes the in-vehicle sensor network, as well as auxiliary sensors, to gather data. Data is transmitted continuously to a central database for academic...... and industrial applications, e.g. research in electric vehicle driving patterns, vehicle substitutability analysis and fleet management. The platform is based on a embedded computer running Linux, and features a high level of modularity and flexibility. The system operates independently of the make of the car......, by using the On-board Diagnostic port to identify car model and adapt its software accordingly. By utilizing on-board Global Navigation Satellite System, General Packet Radio Service, accelerometer, gyroscope and magnetometer, the system not only provides valuable data for research in the field of electric...

  3. Language acquisition is language change. (United States)

    Crain, Stephen; Goro, Takuya; Thornton, Rosalind


    According to the theory of Universal Grammar, the primary linguistic data guides children through an innately specified space of hypotheses. On this view, similarities between child-English and adult-German are as unsurprising as similarities between cousins who have never met. By contrast, experience-based approaches to language acquisition contend that child language matches the input, with nonadult forms being simply less articulated versions of the forms produced by adults. This paper reports several studies that provide support for the theory of Universal grammar, and resist explanation on experience-based accounts. Two studies investigate English-speaking children's productions, and a third examines the interpretation of sentences by Japanese speaking children. When considered against the input children are exposed to, the findings of these and other studies are consistent with the continuity hypothesis, which supposes that child language can differ from the language spoken by adults only in ways that adult languages can differ from each other.

  4. Interface dynamics and banding in rapid solidification

    Energy Technology Data Exchange (ETDEWEB)

    Karma, A.; Sarkissian, A. (Physics Department, Northeastern University, Boston, Massachusetts 02115 (United States))


    Rapid-solidification experiments on metallic alloys in the last decade have provided widespread observations of a novel banded structure.'' We report the results of numerical and analytical studies of the interface dynamics underlying the formation of this structure in a model of directional solidification which includes both solute and heat diffusion and nonequilibrium effects. The thrust of these studies is on the unsteady dynamics of the planar interface and thermal effects. The main conclusion is that the origin of banding can be related to relaxation oscillations of the solidification front, characterized by large variations of the interface velocity, which are dramatically affected by latent-heat diffusion. Without the latter, the oscillations are found to be reasonably well approximated by the phenomenological model of Carrard [ital et] [ital al]. [Acta Metall. 40, 983 (1992)], and the band spacing is inversely proportional to the temperature gradient. In contrast, with latent-heat diffusion the band spacing is insensitive to the temperature gradient, but is controlled instead by the interplay of solute and heat diffusion. The smallness of the solutal diffusivity to thermal diffusivity ratio is exploited to explain analytically this effect and to derive considerably simpler equations of interface motion that provide an efficient numerical means to study the nonplanar interface dynamics expected to cause dark bands. A reasonable agreement with experiment is found for the spacing of banded structures dominated by light-band microsegregation-free regions in Al-Fe alloys.

  5. 75 FR 53169 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-45; Small Entity Compliance Guide (United States)


    ... precedes this document. These documents are also available via the Internet at Acquisition Regulation; Federal Acquisition Circular 2005-45; Small Entity Compliance Guide AGENCIES...

  6. 76 FR 39231 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-53; Introduction (United States)


    ... Acquisition Regulation; Federal Acquisition Circular 2005-53; Introduction AGENCIES: Department of Defense (Do...), published in the Federal Register at 74 FR 51225 on October 6, 2009, entitled ``Federal Leadership on...

  7. Transitional Governance in External Technology Trajectories : Connecting Pre-acquisition collaboration to post-acquisition integration

    NARCIS (Netherlands)

    Faems, D.L.M.


    Collaboration and acquisition have traditionally been observed as two alternative strategies to get access to external technologies. However, real option scholars have recently argued that firms can also engage in transitional technology sourcing trajectories where collaboration and acquisition are

  8. 77 FR 19975 - VA Acquisition Regulation: Simplified Acquisition Procedures for Health-Care Resources (Section... (United States)


    ... Service (003A2A), Office of Acquisition, Logistics and Construction, Department of Veterans Affairs, 810... concept in acquisitions that all offerors are treated fairly. Consideration may be given to updating the...

  9. Assessment of a combined spin- and gradient-echo (SAGE) DSC-MRI method for preclinical neuroimaging. (United States)

    Stokes, Ashley M; Skinner, Jack T; Quarles, C Chad


    The goal of this study was to optimize and validate a combined spin- and gradient-echo (SAGE) sequence for dynamic susceptibility-contrast magnetic resonance imaging to obtain hemodynamic parameters in a preclinical setting. The SAGE EPI sequence was applied in phantoms and in vivo rat brain (normal, tumor, and stroke tissue). Partial and full Fourier encoding schemes were implemented and characterized. Maps of cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT), vessel size index (VSI), volume transfer constant (K(trans)), and volume fraction of the extravascular extracellular space (ve) were obtained. Partial Fourier encoding provided shortened echo times with acceptable signal-to-noise ratio and temporal stability, thus enabling reliable characterization of T2, T2(*) and T1 in both phantoms and rat brain. The hemodynamic parameters CBV, CBF, and MTT for gradient-echo and spin-echo contrast were determined in tumor and stroke; VSI, K(trans), and ve were also computed in tumor tissue. The SAGE EPI sequence allows the acquisition of multiple gradient- and spin-echoes, from which measures of perfusion, permeability, and vessel size can be obtained in a preclinical setting. Partial Fourier encoding can be used to minimize SAGE echo times and reliably quantify dynamic T2 and T2(*) changes. This acquisition provides a more comprehensive assessment of hemodynamic status in brain tissue with vascular and perfusion abnormalities. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. The Contribution of Drug Overdose to Educational Gradients in Life Expectancy in the United States, 1992-2011. (United States)

    Ho, Jessica Y


    Since the mid-1990s, the United States has witnessed a dramatic rise in drug overdose mortality. Educational gradients in life expectancy widened over the same period, and drug overdose likely plays a role in this widening, particularly for non-Hispanic whites. The contemporary drug epidemic is distinctive in terms of its scope, the nature of the substances involved, and its geographic patterning, which influence how it impacts different education groups. I use vital statistics and National Health Interview Survey data to examine the contribution of drug overdose to educational gradients in life expectancy from 1992-2011. I find that over this period, years of life lost due to drug overdose increased for all education groups and for both males and females. The contribution of drug overdose to educational gradients in life expectancy has increased over time and is greater for non-Hispanic whites than for the population as a whole. Drug overdose accounts for a sizable proportion of the increases in educational gradients in life expectancy, particularly at the prime adult ages (ages 30-60), where it accounts for 25 % to 100 % of the widening in educational gradients between 1992 and 2011. Drug overdose mortality has increased more rapidly for females than for males, leading to a gender convergence. These findings shed light on the processes driving recent changes in educational gradients in life expectancy and suggest that effective measures to address the drug overdose epidemic should take into account its differential burden across education groups.

  11. Compressive and extensive strain along gradient trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Gampert, Markus; Goebbert, Jens Henrik; Schaefer, Philip; Gauding, Michael; Peters, Norbert [Institut fuer Technische Verbrennung, RWTH Aachen (Germany); Aldudak, Fettah; Oberlack, Martin, E-mail: [Fachgebiet fuer Stroemungsdynamik, Technische Universitaet Darmstadt (Germany)


    Based on direct numerical simulations of forced turbulence, shear turbulence, decaying turbulence, a turbulent channel flow as well as a Kolmogorov flow with Taylor based Reynolds numbers Re{sub {lambda}} between 69 and 295, the normalized probability density function of the length distribution P-tilde (l-tilde) of dissipation elements, the conditional mean scalar difference < {Delta}k | l > at the extreme points as well as the scaling of the two-point velocity difference along gradient trajectories < {Delta}u{sub n}> are studied. Using the field of the instantanous turbulent kinetic energy k as a scalar, we find a good agreement between the model equation for P-tilde (l-tilde) as proposed by Wang and Peters (2008) and the results obtained in the different DNS cases. This confirms the independance of the model solution from both, the Reynolds number and the type of turbulent flow, so that it can be considered universally valid. In addition, we show a 2/3 scaling for the mean conditional scalar difference. In the second part of the paper, we examine the scaling of the conditional two-point velocity difference along gradient trajectories. In particular, we compare the linear s/{tau} scaling, where {tau} denotes an integral time scale and s the separation arclength along a gradient trajectory in the inertial range as derived by Wang (2009) with the s {center_dot} a{sub {infinity}} scaling, where a{sub {infinity}} denotes the asymtotic value of the conditional mean strain rate of large dissipation elements.

  12. Damping of toroidal ion temperature gradient modes

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, H. [National Inst. for Fusion Science, Toki, Gifu (Japan)


    The temporal evolution of linear toroidal ion temperature gradient (ITG) modes is studied based on a kinetic integral equation including an initial condition. It is shown how to evaluate the analytic continuation of the integral kernel as a function of a complex-valued frequency, which is useful for analytical and numerical calculations of the asymptotic damping behavior of the ITG mode. In the presence of the toroidal {nabla}B-curvature drift, the temporal dependence of the density and potential perturbations consists of normal modes and a continuum mode, which correspond to contributions from poles and from an integral along a branch cut, respectively, of the Laplace-transformed potential function of the complex-valued frequency. The normal modes have exponential time dependence with frequencies and growth rates determined by the dispersion relation while the continuum mode, which has a ballooning structure, shows a power law decay {proportional_to} t{sup -2} in the asymptotic limit, where t is the time variable. Therefore, the continuum mode dominantly describes the long-time asymptotic behavior of the density and potential perturbations for the stable system where all normal modes have negative growth rates. By performing proper analytic continuation for the homogeneous version of the kinetic integral equation, dependences of the normal modes` growth rate, real frequency, and eigenfunction on {eta}{sub i} (the ratio of the ion temperature gradient to the density gradient), k{sub {theta}} (the poloidal wavenumber), s (the magnetic shear parameter), and {theta}{sub k} (the ballooning angle corresponding to the minimum radial wavenumber) are numerically obtained for both stable and unstable cases. (author)

  13. Stochastic stability of measures in gradient systems (United States)

    Huang, Wen; Ji, Min; Liu, Zhenxin; Yi, Yingfei


    Stochastic stability of a compact invariant set of a finite dimensional, dissipative system is studied in our recent work "Concentration and limit behaviors of stationary measures" (Huang et al., 2015) for general white noise perturbations. In particular, it is shown under some Lyapunov conditions that the global attractor of the systems is always stable under general noise perturbations and any strong local attractor in it can be stabilized by a particular family of noise perturbations. Nevertheless, not much is known about the stochastic stability of an invariant measure in such a system. In this paper, we will study the issue of stochastic stability of invariant measures with respect to a finite dimensional, dissipative gradient system with potential function f. As we will show, a special property of such a system is that it is the set of equilibria which is stable under general noise perturbations and the set Sf of global minimal points of f which is stable under additive noise perturbations. For stochastic stability of invariant measures in such a system, we will characterize two cases of f, one corresponding to the case of finite Sf and the other one corresponding to the case when Sf is of positive Lebesgue measure, such that either some combined Dirac measures or the normalized Lebesgue measure on Sf is stable under additive noise perturbations. However, we will show by constructing an example that such measure stability can fail even in the simplest situation, i.e., in 1-dimension there exists a potential function f such that Sf consists of merely two points but no invariant measure of the corresponding gradient system is stable under additive noise perturbations. Crucial roles played by multiplicative and additive noise perturbations to the measure stability of a gradient system will also be discussed. In particular, the nature of instabilities of the normalized Lebesgue measure on Sf under multiplicative noise perturbations will be exhibited by an example.

  14. Compensation of slice profile mismatch in combined spin- and gradient-echo echo-planar imaging pulse sequences. (United States)

    Schmiedeskamp, Heiko; Straka, Matus; Bammer, Roland


    Combined acquisition of gradient-echo and spin-echo signals in MRI time series reveals additional information for perfusion-weighted imaging and functional MRI because of differences in the sensitivity of gradient-echo and spin-echo measurements to the properties of the underlying vascular architecture. The acquisition of multiple echo trains within one time frame facilitates the simultaneous estimation of the transversal relaxation parameters R2 and R2*. However, the simultaneous estimation of these parameters tends to be incorrect in the presence of slice profile mismatches between signal excitation and subsequent refocusing pulses. It is shown here that improvements in pulse design reduced R2 and R2* estimation errors. Further improvements were achieved by augmented parameter estimation through the introduction of an additional parameter δ to correct for discordances in slice profiles to facilitate more quantitative measurements. Moreover, the analysis of time-resolved acquisitions revealed that the temporal stability of R2 estimates could be increased with improved pulse design, counteracting low contrast-to-noise ratios in spin-echo-based perfusion and functional MRI. Copyright © 2011 Wiley Periodicals, Inc.

  15. Diverse belowground resource strategies underlie plant species coexistence and spatial distribution in three grasslands along a precipitation gradient. (United States)

    Li, Hongbo; Liu, Bitao; McCormack, M Luke; Ma, Zeqing; Guo, Dali


    Functional traits and their variation mediate plant species coexistence and spatial distribution. Yet, how patterns of variation in belowground traits influence resource acquisition across species and plant communities remains obscure. To characterize diverse belowground strategies in relation to species coexistence and abundance, we assessed four key belowground traits - root diameter, root branching intensity, first-order root length and mycorrhizal colonization - in 27 coexisting species from three grassland communities along a precipitation gradient. Species with thinner roots had higher root branching intensity, but shorter first-order root length and consistently low mycorrhizal colonization, whereas species with thicker roots enhanced their capacity for resource acquisition by producing longer first-order roots and maintaining high mycorrhizal colonization. Plant species observed across multiple sites consistently decreased root branching and/or mycorrhizal colonization, but increased lateral root length with decreasing precipitation. Additionally, the degree of intraspecific trait variation was positively correlated with species abundance across the gradient, indicating that high intraspecific trait variation belowground may facilitate greater fitness and chances of survival across multiple habitats. These results suggest that a small set of critical belowground traits can effectively define diverse resource acquisition strategies in different environments and may forecast species survival and range shifts under climate change. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  16. Polyvalent cationic metals induce the rate of transferrin-independent iron acquisition by HL-60 cells. (United States)

    Olakanmi, O; Stokes, J B; Pathan, S; Britigan, B E


    The trivalent metals iron, aluminum, and gallium greatly increase the rate of iron acquisition from low molecular weight chelates by human myeloid cells. The present study explores the mechanism responsible. Gallium-induced iron acquisition was shown to lead to stable cellular association of iron, the magnitude of which varied with the chelate to which the iron was bound. The majority of this iron initially associated with the plasma membrane. Cellular depletion of ATP did not affect the response to gallium nor did it require the continued presence of extracellular gallium. However, continued cell association of gallium was needed as subsequent cellular exposure to metal chelators resulted in a rapid loss of the "induced" phenotype. Other trivalent metals (lanthanum and gadolinium) and tetravalent metals (tin and zirconium) but not divalent metals also induced iron acquisition. Neither enhanced iron reduction nor protein kinase C or tyrosine kinases appeared involved in gallium-mediated induction of iron acquisition. Exposure of HL-60 cells to polyvalent cationic metals results in a dramatic and sustained increase in the rate of iron acquisition from low molecular weight chelating agents. This could be important for the rapid clearance of iron by phagocytes from the extracellular environment at sites of local tissue damage.

  17. Smoothed Analysis for the Conjugate Gradient Algorithm (United States)

    Menon, Govind; Trogdon, Thomas


    The purpose of this paper is to establish bounds on the rate of convergence of the conjugate gradient algorithm when the underlying matrix is a random positive definite perturbation of a deterministic positive definite matrix. We estimate all finite moments of a natural halting time when the random perturbation is drawn from the Laguerre unitary ensemble in a critical scaling regime explored in Deift et al. (2016). These estimates are used to analyze the expected iteration count in the framework of smoothed analysis, introduced by Spielman and Teng (2001). The rigorous results are compared with numerical calculations in several cases of interest.

  18. Gradient based filtering of digital elevation models

    DEFF Research Database (Denmark)

    Knudsen, Thomas; Andersen, Rune Carbuhn

    We present a filtering method for digital terrain models (DTMs). The method is based on mathematical morphological filtering within gradient (slope) defined domains. The intention with the filtering procedure is to improbé the cartographic quality of height contours generated from a DTM based...... on draping and optimum interpolation methods. The contours from the unfiltered DTM has shown to become ragged and hard-to-interpret—especially in areas of minor slope. The contours from the filtered DTM are significantly more smooth. They are however not smoothed to an extent where local breaks...

  19. Human impact gradient on mammalian biodiversity

    Directory of Open Access Journals (Sweden)

    Mariana Munguía


    Full Text Available Drastic changes have been caused by human influence in natural landscapes, which may exert an intensive effect on species loss. However, species loss from human pressure is not random but depends on a series of environmentally associated factors. Linking species traits to environmental attributes may allow us to detect the ecological impacts of habitat so that meaningful habitat degradation gradients can be identified. The relationships between environmental factors and species traits provide the basis for identifying those biological traits that make species more sensitive to disturbance. These relationships are also helpful to detect the geographic distribution of latent risk to reveal areas where biodiversity is threatened. Here, we identify a “Human Impact Gradient for Biodiversity (HIGB” based on a three-table ordination method (RLQ analysis and fourth-corner analysis to identify key species traits that are associated with environmental gradient. Species distribution and environmental geographic data were gathered nationwide to analyze 68 localities, which represent 27% of Mexico’s surface, including 211 species of mammals. Nine environmental variables (including biophysical, geophysical and land-use impacts were analyzed by using the Geographic Information System. Three types of species’ traits were evaluated: locomotion, trophic habit and body size. We identified a human impact gradient, which was mainly determined by the percentage of the area that was covered by seedlings, the plant richness, the understory coverage percentage and the human settlement index. The most important species traits that are associated with non-human-impacted sites were carnivores, frugivores–herbivores and a body size that was greater than 17.8 kg; 25 species were selected by the decision criteria framework for species that were sensitive to degradation based on ecological function information. Conversely, granivores, fossorial and semifossorial

  20. Gradient-index optics fundamentals and applications

    CERN Document Server

    Gomez-Reino, Carlos; Bao, Carmen


    Gradient-Index (GRIN) optics provides a comprehensive and thorough treatment on fundamentals and applications of light propagation through inhomogeneous media. The book can be used both as a classroom text for students in physics and engineering and as a reference for specialists. A description of the phenomena, components and technology used in GRIN Optics are presented. The relationship to lenses, waveguides, optical connections, spatial solitons and vision is demonstrated. Applications of GRIN components and hybrid structures for optical connections, optical sensing and Talbot effect are analyzed.

  1. Quasi parton distributions and the gradient flow (United States)

    Monahan, Christopher; Orginos, Kostas


    We propose a new approach to determining quasi parton distribution functions (PDFs) from lattice quantum chromodynamics. By incorporating the gradient flow, this method guarantees that the lattice quasi PDFs are finite in the continuum limit and evades the thorny, and as yet unresolved, issue of the renormalization of quasi PDFs on the lattice. In the limit that the flow time is much smaller than the length scale set by the nucleon momentum, the moments of the smeared quasi PDF are proportional to those of the lightfront PDF. We use this relation to derive evolution equations for the matching kernel that relates the smeared quasi PDF and the light-front PDF.

  2. Impact of Ozone Gradient on Grapevine Leaves (United States)

    Alebic-Juretic, Ana; Bokan-Vucelic, Itana; Mifka, Boris; Zatezalo, Marija; Zubak, Velimir


    Due to complex orography and air mass circulation, the Rijeka Bay area is characterized by O3 gradient, with concentrations risen with the altitude (1). Therefore AOT40 values were often exceeded and should result in harmful effects on vegetation. Based on previous controlled experiments (2), we examined the possible effect of atmospheric ozone on grape leaves under natural O3 gradient. Grapevine leaves (2-5) were collected from May to September 2016 at two sampling points in the proximity of two AQM stations: Site 1 in the city centre (20m asl) and Site 2 (186m asl) in the suburban settlement. Subsequent to weighing and determination of surface area, the leaves (0,5 g) were extracted in 95% ethanol and analysed on chlorophyl a (Chla), chlorophyl b (Chlb) and carotene (Car) content by UV-VIS spectrometry on 3 wavelengths (664, 649, 470 nm) (3) In summer 2016 O3 gradient was not that pronounced as usual (1), but stil the concentrations differed by approx. 20%, exceeding national AOT40 value at both sites (22.360 and 28.061 μg m-3 h, respectively, at Sites 1 and 2). The concentrations of other pollutants were bellow limit values (LV). The Cha and Chb in a sample leaves collected at the end of May at Site 2 are equal to that with filtered O3 in control experiment (2), i.e. without damage caused by ozone, while the Car content is lower approx. 50% and is kept at the same level. The con-centrations of pigments obtained in July prooved the possible damage by O3, while in subsequent months could speed up natural ageing. This is the first evidence of O3 damage on plants in the Rijeka Bay area, in spite of weaker O3 gradient and lacking visible signs of damage. Preliminary results indicate the need for more frequent sampling, particularly in the period included in AOT40 (May-July). References: 1. Alebić-Juretić A (2012) Int J Remote Sensing, 33(2): 335-345 2. Britvec M, Reichenauer T, Soja G., Ljubešić N, Pećina M (2001) Biologia (Bratislava),56/4: 417-424 3. Sumanata

  3. The educational gradient in coronary heart disease

    DEFF Research Database (Denmark)

    Ariansen, Inger; Mortensen, Laust Hvas; Igland, Jannicke


    BACKGROUND: Independently of cardiovascular disease (CVD) risk factors, cognitive ability may account for some of the excess risk of coronary heart disease (CHD) associated with lower education. We aimed to assess how late adolescence cognitive ability and midlife CVD risk factors are associated...... with the educational gradient in CHD in Norway. METHODS: In a cohort of 57 279 men born during 1949-1959, health survey information was linked to military conscription records of cognitive ability, to national educational data, to hospitalisation records from the Cardiovascular Disease in Norway (CVDNOR) project...

  4. Method of thermal derivative gradient analysis (TDGA

    Directory of Open Access Journals (Sweden)

    M. Cholewa


    Full Text Available In this work a concept of thermal analysis was shown, using for crystallization kinetics description the temperature derivatives after time and direction. Method of thermal derivative gradient analysis (TDGA is assigned for alloys and metals investigation as well as cast composites in range of solidification. The construction and operation characteristics were presented for the test stand including processing modules and probes together with thermocouples location. Authors presented examples of results interpretation for AlSi11 alloy castings with diversified wall thickness and at different pouring temperature.

  5. Complex surface concentration gradients by stenciled "electro click chemistry". (United States)

    Hansen, Thomas S; Lind, Johan U; Daugaard, Anders E; Hvilsted, Søren; Andresen, Thomas L; Larsen, Niels B


    Complex one- or two-dimensional concentration gradients of alkynated molecules are produced on azidized conducting polymer substrates by stenciled "electro click chemistry". The latter describes the local electrochemical generation of catalytically active Cu(I) required to complete a "click reaction" between alkynes and azides at room temperature. A stencil on the counter electrode defines the shape and multiplicity of the gradient(s) on the conducting polymer substrate, while the specific reaction conditions control gradient steepness and the maximum concentration deposited. Biologically active ligands including cell binding peptides are patterned in gradients by this method without losing their biological function or the conductivity of the polymer.

  6. Data Acquisition for Land Subsidence Control (United States)

    Zhu, Y.; Balke, K.


    For controlling land subsidence caused by groundwater over-exploitation, loading of engineered structures, mining and other anthropogenic activities in this fast changing world, a large variety of different data of various scales of concerning areas are needed for scientific study and administrative operational purposes. The economical, social and environmental impacts of anthropogenic land subsidence have long been recognized by many scientific institutions and management authorities based on results of monitoring and analysis at an interdisciplinary level. The land subsidence information systems composed of the surface and subsurface monitoring nets (monitoring and development wells, GPS stations and other facilities) and local data processing centers as a system management tool in Shanghai City was started with the use of GPS technology to monitor land subsidence in 1998. After years of experiences with a set of initiatives by adopting adequate countermeasures, the particular attention given to new improved methodologies to monitor and model the process of land subsidence in a simple and timely way, this is going to be promoted in the whole Yangtze River Delta region in China, where land subsidence expands in the entire region of urban cluster. The Delta land subsidence monitoring network construction aims to establish an efficient and coordinated water resource management system. The land subsidence monitoring network records "living history" of land subsidence, produces detailed scheduled reports and environmental impact statements. For the different areas with local factors and site characteristics, parallel packages need to be designed for predicting changes, land sensitivity and uncertainty analysis, especially for the risk analysis in the rapid growth of megacities and urban areas. In such cases, the new models with new types of local data and the new ways of data acquisition provide the best information for the decision makers for their mitigating

  7. 75 FR 14067 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-40; Small Entity Compliance Guide (United States)


    ... the Internet at . FOR FURTHER INFORMATION CONTACT: The analyst whose name... Acquisition Regulation; Federal Acquisition Circular 2005-40; Small Entity Compliance Guide AGENCIES... Federal Acquisition Regulation (FAR). Interested parties may obtain further information regarding this...

  8. 75 FR 39420 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-44; Small Entity Compliance Guide (United States)


    ... the Internet at . FOR FURTHER INFORMATION CONTACT: The analyst whose name... Acquisition Regulation; Federal Acquisition Circular 2005-44; Small Entity Compliance Guide AGENCY: Department... Federal Acquisition Regulation (FAR). Interested parties may obtain further information regarding this...

  9. 75 FR 19179 - Federal Acquisition Regulation; Federal Acquisition Circular 2005-41; Small Entity Compliance Guide (United States)


    ... Acquisition Regulation; Federal Acquisition Circular 2005-41; Small Entity Compliance Guide AGENCIES... the summary of the rule appearing in Federal Acquisition Circular (FAC) 2005-41 which amends the... construction projects where the total cost to the Government is $25 million or more in order to promote economy...

  10. How different are monolingual and bilingual acquisition? How different are monolingual and bilingual acquisition?

    Directory of Open Access Journals (Sweden)

    Annick De Houwer


    Full Text Available This paper compares monolingual acquisition to the acquisition of two languages from infancy. Basis for the comparison is the acquisition literature. Specifically for bilingual acquisition, the paper relies on findings from studies on young bilingual children who together are acquiring 13 languages in 14 different combinations. The data available to date strongly suggest that in essence, bilingual and monolingual children go through the primary language development process in fundamentally similar ways. There are also striking similarities between bilingual and monolingual children for one particular language-in-acquisition. The acquisition process, then, appears to be very robust, and quite immune to the fact whether a child is growing up with two languages or just one. This paper compares monolingual acquisition to the acquisition of two languages from infancy. Basis for the comparison is the acquisition literature. Specifically for bilingual acquisition, the paper relies on findings from studies on young bilingual children who together are acquiring 13 languages in 14 different combinations. The data available to date strongly suggest that in essence, bilingual and monolingual children go through the primary language development process in fundamentally similar ways. There are also striking similarities between bilingual and monolingual children for one particular language-in-acquisition. The acquisition process, then, appears to be very robust, and quite immune to the fact whether a child is growing up with two languages or just one.

  11. 76 FR 30362 - Federal Acquisition Regulation; Submission for OMB Review; Acquisition of Helium (United States)


    ...; Submission for OMB Review; Acquisition of Helium AGENCY: Department of Defense (DOD), General Services... approved information collection requirement concerning acquisition of helium. Public comments are... Collection 9000- 0113, Acquisition of Helium, by any of the following methods: : http://www...

  12. Enseignement des langues et theories d'acquisition Sprachunterricht unde Spracherwerbstheorien. (Language Teaching and Acquisition Theories). (United States)

    Schwarz, Alexander, Ed.


    This collection of articles on language teaching and language acquisition theories includes: "Enseignement des langues et theories de l'acquisition. Introduction au colloque" ("Language Teaching and Theories of Acquisition. Introduction to the Colloquium") (Rene Richterich); "Apprendre une langue dans l'interaction verbale" ("Language Learning in…

  13. Regularized Multitask Learning for Multidimensional Log-Density Gradient Estimation. (United States)

    Yamane, Ikko; Sasaki, Hiroaki; Sugiyama, Masashi


    Log-density gradient estimation is a fundamental statistical problem and possesses various practical applications such as clustering and measuring nongaussianity. A naive two-step approach of first estimating the density and then taking its log gradient is unreliable because an accurate density estimate does not necessarily lead to an accurate log-density gradient estimate. To cope with this problem, a method to directly estimate the log-density gradient without density estimation has been explored and demonstrated to work much better than the two-step method. The objective of this letter is to improve the performance of this direct method in multidimensional cases. Our idea is to regard the problem of log-density gradient estimation in each dimension as a task and apply regularized multitask learning to the direct log-density gradient estimator. We experimentally demonstrate the usefulness of the proposed multitask method in log-density gradient estimation and mode-seeking clustering.

  14. Rapid surface sampling and archival record system

    Energy Technology Data Exchange (ETDEWEB)

    Barren, E.; Penney, C.M.; Sheldon, R.B. [GE Corporate Research and Development Center, Schenectady, NY (United States)] [and others


    A number of contamination sites exist in this country where the area and volume of material to be remediated is very large, approaching or exceeding 10{sup 6} m{sup 2} and 10{sup 6} m{sup 3}. Typically, only a small fraction of this material is actually contaminated. In such cases there is a strong economic motivation to test the material with a sufficient density of measurements to identify which portions are uncontaminated, so extensively they be left in place or be disposed of as uncontaminated waste. Unfortunately, since contamination often varies rapidly from position to position, this procedure can involve upwards of one million measurements per site. The situation is complicated further in many cases by the difficulties of sampling porous surfaces, such as concrete. This report describes a method for sampling concretes in which an immediate distinction can be made between contaminated and uncontaminated surfaces. Sample acquisition and analysis will be automated.

  15. Kuwaiti Arabic: Acquisition of Singleton Consonants (United States)

    Ayyad, Hadeel Salama; Bernhardt, B. May; Stemberger, Joseph P.


    Background: Arabic, a Semitic language of the Afro-Asiatic variety, has a rich consonant inventory. Previous studies on Arabic phonological acquisition have focused primarily on dialects in Jordan and Egypt. Because Arabic varies considerably across regions, information is also needed for other dialects. Aims: To determine acquisition benchmarks…

  16. KARMA: The Knowledge Acquisition Reference Multimedia Aid. (United States)

    Liebowitz, Jay; Letsky, Christine


    Discussion of multimedia instructional materials focuses on the development of KARMA (Knowledge Acquisition Reference Multimedia Aid) to help students learn about the expert system, development process. Highlights include knowledge acquisition in expert systems development, interviewing methods to obtain experts' knowledge, models and examples,…

  17. Towards a Theory of Language Acquisition

    NARCIS (Netherlands)

    Kampen, Jacqueline van

    "We have seen at the workshop a diversity of measurements and a no less diverse amount of different phenomena. Shared areas were acquisition phenomena in Romance languages and more general: the beginnings for a true theory of language acquisition. I will not attempt to evaluate the various

  18. Managing in a merger and acquisition era. (United States)

    Holdren, R C


    Medical group administrators are quickly learning what big business has known for years-mergers and acquisitions represent a new and powerful option. If this option is to be employed successfully, however, group management has to understand the terms and be prepared well before merger or acquisition talk begins.

  19. Neural Plasticity in Speech Acquisition and Learning (United States)

    Zhang, Yang; Wang, Yue


    Neural plasticity in speech acquisition and learning is concerned with the timeline trajectory and the mechanisms of experience-driven changes in the neural circuits that support or disrupt linguistic function. In this selective review, we discuss the role of phonetic learning in language acquisition, the "critical period" of learning, the agents…

  20. Foreign acquisition, plant survival, and employment growth

    DEFF Research Database (Denmark)

    Bandick, Roger; Görg, Holger


    This paper analyzes the effect of foreign acquisition on survival and employment growth of targets using data on Swedish manufacturing plants.We separate targeted plants into those within Swedish MNEs, Swedish exporting non-MNEs, and purely domestic firms. The results, controlling for possible...... acquisitions. We find robust positive employment growth effects only for exporters and only if the takeover is vertical....

  1. 32 CFR 21.605 - Acquisition. (United States)


    ... 32 National Defense 1 2010-07-01 2010-07-01 false Acquisition. 21.605 Section 21.605 National Defense Department of Defense OFFICE OF THE SECRETARY OF DEFENSE DoD GRANT AND AGREEMENT REGULATIONS DoD GRANTS AND AGREEMENTS-GENERAL MATTERS Definitions § 21.605 Acquisition. The acquiring (by purchase, lease...

  2. Input and Intake in Language Acquisition (United States)

    Gagliardi, Ann C.


    This dissertation presents an approach for a productive way forward in the study of language acquisition, sealing the rift between claims of an innate linguistic hypothesis space and powerful domain general statistical inference. This approach breaks language acquisition into its component parts, distinguishing the input in the environment from…

  3. Child Language Acquisition: Contrasting Theoretical Approaches (United States)

    Ambridge, Ben; Lieven, Elena V. M.


    Is children's language acquisition based on innate linguistic structures or built from cognitive and communicative skills? This book summarises the major theoretical debates in all of the core domains of child language acquisition research (phonology, word-learning, inflectional morphology, syntax and binding) and includes a complete introduction…

  4. EBT data acquisition and analysis system

    Energy Technology Data Exchange (ETDEWEB)

    Burris, R.D.; Greenwood, D.E.; Stanton, J.S.; Geoffroy, K.A.


    This document describes the design and implementation of a data acquisition and analysis system for the EBT fusion experiment. The system includes data acquisition on five computers, automatic transmission of that data to a large, central data base, and a powerful data retrieval system. The system is flexible and easy to use, and it provides a fully documented record of the experiments.

  5. Factors influencing children's interpretation and acquisition of ...

    African Journals Online (AJOL)


    quantitatively analysed using Statistical Package for Social. Sciences (SPSS). The results showed that children's interpretation and acquisition of idioms is not dependent on the analysability and internal structure of the idioms, although these may affect interpretation and acquisition. The idiom can be analysable or can.

  6. Webpage Segments Classification with Incremental Knowledge Acquisition (United States)

    Guo, Wei; Kim, Yang Sok; Kang, Byeong Ho

    This paper suggests an incremental information extraction method for social network analysis of web publications. For this purpose, we employed an incremental knowledge acquisition method, called MCRDR (Multiple Classification Ripple-Down Rules), to classify web page segments. Our experimental results show that our MCRDR-based web page segments classification system successfully supports easy acquisition and maintenance of information extraction rules.

  7. Rapid manufacturing facilitated customisation


    Tuck, Christopher John; Hague, Richard; Ruffo, Massimiliano; Ransley, Michelle; Adams, Paul Russell


    Abstract This paper describes the production of body-fitting customised seat profiles utilising the following digital methods: three dimensional laser scanning, reverse engineering and Rapid Manufacturing (RM). The seat profiles have been manufactured in order to influence the comfort characteristics of an existing ejector seat manufactured by Martin Baker Aircraft Ltd. The seat, known as Navy Aircrew Common Ejection Seat (NACES), was originally designed with a generic profile. ...

  8. Rapid Detection of Pathogens

    Energy Technology Data Exchange (ETDEWEB)

    David Perlin


    Pathogen identification is a crucial first defense against bioterrorism. A major emphasis of our national biodefense strategy is to establish fast, accurate and sensitive assays for diagnosis of infectious diseases agents. Such assays will ensure early and appropriate treatment of infected patients. Rapid diagnostics can also support infection control measures, which monitor and limit the spread of infectious diseases agents. Many select agents are highly transmissible in the early stages of disease, and it is critical to identify infected patients and limit the risk to the remainder of the population and to stem potential panic in the general population. Nucleic acid-based molecular approaches for identification overcome many of the deficiencies associated with conventional culture methods by exploiting both large- and small-scale genomic differences between organisms. PCR-based amplification of highly conserved ribosomal RNA (rRNA) genes, intergenic sequences, and specific toxin genes is currently the most reliable approach for bacterial, fungal and many viral pathogenic agents. When combined with fluorescence-based oligonucleotide detection systems, this approach provides real-time, quantitative, high fidelity analysis capable of single nucleotide allelic discrimination (4). These probe systems offer rapid turn around time (<2 h) and are suitable for high throughput, automated multiplex operations that are critical for clinical diagnostic laboratories. In this pilot program, we have used molecular beacon technology invented at the Public health Research Institute to develop a new generation of molecular probes to rapidly detect important agents of infectious diseases. We have also developed protocols to rapidly extract nucleic acids from a variety of clinical specimen including and blood and tissue to for detection in the molecular assays. This work represented a cooperative research development program between the Kramer-Tyagi/Perlin labs on probe development

  9. Gradient hydrogel coatings for medical applications (United States)

    Chinnayan Kannan, Pandiyarajan; Genzer, Jan

    Mussel byssus is a typical example for gradient material that demonstrates a continues variation in mechanical property (or modulus), i . e . , soft (proximal) part is connected to mussel, while the stiffer (distal) part facilitates the attachment of mussel to a stone. Mimicking such materials is highly demanding especially in the areas of artificial implants. We developed a simple synthetic route to produce gradient hydrogels that are covalently anchored to the substrate. N-isopropylacrylamide has been copolymerized with 5 mole% of photo-active (methacrylyloxybenzophenone) and/or 5% of thermally-active (styrenesulfonylazide) crosslinkers. The incorporation of photo and/or thermal crosslinkers allows us for a complete control over the network properties in orthogonal directions. A systematic investigation towards the gel kinetics, swelling, crosslink density, elasticity and protein adsorption was performed. Our results instigate that weakly crosslinked (low modulus) gels swell strong in aqueous medium than the densely crosslinked (high modulus) gels. The results of protein adsorption are discussed based on the previously developed model entropic shielding and size exclusion effect.

  10. Asymmetric Uncertainty Expression for High Gradient Aerodynamics (United States)

    Pinier, Jeremy T


    When the physics of the flow around an aircraft changes very abruptly either in time or space (e.g., flow separation/reattachment, boundary layer transition, unsteadiness, shocks, etc), the measurements that are performed in a simulated environment like a wind tunnel test or a computational simulation will most likely incorrectly predict the exact location of where (or when) the change in physics happens. There are many reasons for this, includ- ing the error introduced by simulating a real system at a smaller scale and at non-ideal conditions, or the error due to turbulence models in a computational simulation. The un- certainty analysis principles that have been developed and are being implemented today do not fully account for uncertainty in the knowledge of the location of abrupt physics changes or sharp gradients, leading to a potentially underestimated uncertainty in those areas. To address this problem, a new asymmetric aerodynamic uncertainty expression containing an extra term to account for a phase-uncertainty, the magnitude of which is emphasized in the high-gradient aerodynamic regions is proposed in this paper. Additionally, based on previous work, a method for dispersing aerodynamic data within asymmetric uncer- tainty bounds in a more realistic way has been developed for use within Monte Carlo-type analyses.

  11. The multigrid preconditioned conjugate gradient method (United States)

    Tatebe, Osamu


    A multigrid preconditioned conjugate gradient method (MGCG method), which uses the multigrid method as a preconditioner of the PCG method, is proposed. The multigrid method has inherent high parallelism and improves convergence of long wavelength components, which is important in iterative methods. By using this method as a preconditioner of the PCG method, an efficient method with high parallelism and fast convergence is obtained. First, it is considered a necessary condition of the multigrid preconditioner in order to satisfy requirements of a preconditioner of the PCG method. Next numerical experiments show a behavior of the MGCG method and that the MGCG method is superior to both the ICCG method and the multigrid method in point of fast convergence and high parallelism. This fast convergence is understood in terms of the eigenvalue analysis of the preconditioned matrix. From this observation of the multigrid preconditioner, it is realized that the MGCG method converges in very few iterations and the multigrid preconditioner is a desirable preconditioner of the conjugate gradient method.

  12. Adaptive Gradient Multiobjective Particle Swarm Optimization. (United States)

    Han, Honggui; Lu, Wei; Zhang, Lu; Qiao, Junfei


    An adaptive gradient multiobjective particle swarm optimization (AGMOPSO) algorithm, based on a multiobjective gradient (stocktickerMOG) method and a self-adaptive flight parameters mechanism, is developed to improve the computation performance in this paper. In this AGMOPSO algorithm, the stocktickerMOG method is devised to update the archive to improve the convergence speed and the local exploitation in the evolutionary process. Meanwhile, the self-adaptive flight parameters mechanism, according to the diversity information of the particles, is then established to balance the convergence and diversity of AGMOPSO. Attributed to the stocktickerMOG method and the self-adaptive flight parameters mechanism, this AGMOPSO algorithm not only has faster convergence speed and higher accuracy, but also its solutions have better diversity. Additionally, the convergence is discussed to confirm the prerequisite of any successful application of AGMOPSO. Finally, with regard to the computation performance, the proposed AGMOPSO algorithm is compared with some other multiobjective particle swarm optimization algorithms and two state-of-the-art multiobjective algorithms. The results demonstrate that the proposed AGMOPSO algorithm can find better spread of solutions and have faster convergence to the true Pareto-optimal front.

  13. Intergenerational and socioeconomic gradients of child obesity. (United States)

    Costa-Font, Joan; Gil, Joan


    Can the rise in obesity among children be attributed to the intergenerational transmission of parental influences? Does this trend affect the influence of parent's socioeconomic status on obesity? This paper documents evidence of an emerging social gradient of obesity in pre-school children resulting from a combination of both socio-economic status and less intensive childcare associated with maternal employment, when different forms of intergenerational transmission are controlled for. We also estimate and decompose income related inequalities in child obesity. We take advantage of a uniquely constructed dataset from Spain that contains records form 13,358 individuals for a time period (years 2003-2006) in which a significant spike in the growth of child obesity was observed. Our results suggest robust evidence of both socioeconomic and intergenerational gradients. Results are suggestive of a high income effect in child obesity, alongside evidence that income inequalities have doubled in just three years with a pure income effect accounting for as much as 72-66% of these income inequality estimates, even when intergenerational transmission is accounted for. Although, intergenerational transmission does not appear to be gender specific, when accounted for, mother's labour market participation only explains obesity among boys but not among girls. Hence, it appears income and parental influences are the central determinants of obesity among children. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Temperature gradients assist carbohydrate allocation within trees. (United States)

    Sperling, Or; Silva, Lucas C R; Tixier, Aude; Théroux-Rancourt, Guillaume; Zwieniecki, Maciej A


    Trees experience two distinct environments: thermally-variable air and thermally-buffered soil. This generates intra-tree temperature gradients, which can affect carbon metabolism and water transport. In this study, we investigated whether carbohydrate allocation within trees is assisted by temperature gradients. We studied pistachio (Pistacia integerrima) to determine: (1) temperature-induced variation in xylem sugar concentration in excised branches; (2) changes in carbon allocation in young trees under simulated spring and fall conditions; and (3) seasonal variability of starch levels in mature orchard trees under field conditions. We found that warm branches had less sugar in perfused sap than cold branches due to increasing parenchyma storage. Simulated spring conditions promoted allocation of carbohydrates from cold roots to warm canopy and explained why starch levels surged in canopies of orchard trees during early spring. This driving force of sugar transport is interrupted in fall when canopies are colder than roots and carbohydrate redistribution is compartmentalized. On the basis of these findings, we propose a new mechanistic model of temperature-assisted carbohydrate allocation that links environmental cues and tree phenology. This data-enabled model provides insights into thermal "fine-tuning" of carbohydrate metabolism and a warning that the physiological performance of trees might be impaired by climatic changes.

  15. Determining and correcting "moment bias" in gradient polymer elution chromatography. (United States)

    Striegel, André M


    Gradient polymer elution chromatography (GPEC) is rapidly becoming the analytical method of choice for determining the chemical composition distribution (CCD) of synthetic polymers. GPEC can be performed in traditional (strict precipitation-redissolution mechanism) or interactive (normal- and reversed-phase) modes, and results may be qualitative, semi-quantitative, or fully quantitative. Quantitative approaches have thus far relied on colligative or end group techniques for determining the values of standards used in constructing the GPEC calibration curve. While the values obtained from said methods are number-averages, they are assigned to the peak apexes of the standards (i.e. assigned as peak averages). This creates a determinate error in the quantitation, referred to herein as "moment bias". In this paper we determine moment bias for a series of styrene-acrylonitrile (SAN) copolymers, where the distribution and averages of the AN% have been measured using normal-phase (NP) GPEC. We also correct for the effect via statistical treatment of the chromatographic data.

  16. Inelastic scattering with Chebyshev polynomials and preconditioned conjugate gradient minimization. (United States)

    Temel, Burcin; Mills, Greg; Metiu, Horia


    We describe and test an implementation, using a basis set of Chebyshev polynomials, of a variational method for solving scattering problems in quantum mechanics. This minimum error method (MEM) determines the wave function Psi by minimizing the least-squares error in the function (H Psi - E Psi), where E is the desired scattering energy. We compare the MEM to an alternative, the Kohn variational principle (KVP), by solving the Secrest-Johnson model of two-dimensional inelastic scattering, which has been studied previously using the KVP and for which other numerical solutions are available. We use a conjugate gradient (CG) method to minimize the error, and by preconditioning the CG search, we are able to greatly reduce the number of iterations necessary; the method is thus faster and more stable than a matrix inversion, as is required in the KVP. Also, we avoid errors due to scattering off of the boundaries, which presents substantial problems for other methods, by matching the wave function in the interaction region to the correct asymptotic states at the specified energy; the use of Chebyshev polynomials allows this boundary condition to be implemented accurately. The use of Chebyshev polynomials allows for a rapid and accurate evaluation of the kinetic energy. This basis set is as efficient as plane waves but does not impose an artificial periodicity on the system. There are problems in surface science and molecular electronics which cannot be solved if periodicity is imposed, and the Chebyshev basis set is a good alternative in such situations.

  17. Report and analysis of the BULLION forced-gradient experiment

    Energy Technology Data Exchange (ETDEWEB)



    The BULLION Forced-Gradient Experiment (FGE) was conducted in the summer of 1997, starting June 2 and ending August 28. The site of the experiment was the ER-20-6 well field adjacent to the BULLION test. Figure 1-1 shows the location of this site on Pahute Mesa in Area 20 of the Nevada Test Site. Figure 1-2 shows the ER-20-6 site within the Pahute Mesa hydrogeologic framework, and Figure 1-3 shows the site layout with respect to the BULLION test. The purpose of the BULLION FGE was to provide information relevant to the transport of radionuclides in groundwater. Transport of radionuclides from Pahute Mesa is of special concern due to the potential for rapid movement of groundwater in the fractured volcanic rocks comprising the Mesa and formations along the anticipated downgradient path of groundwater. The objective was specifically to observe the transport process and characterize transport parameters (e.g., effective porosity, dispersivity and matrix diffusion) for use in predictive modeling of contaminant transport. Additional objectives were to characterize the hydrologic source term and the relative mobility of mobile radionuclides.

  18. Luminescence from cavitation bubbles deformed in uniform pressure gradients (United States)

    Supponen, Outi; Obreschkow, Danail; Kobel, Philippe; Farhat, Mohamed


    Presented here are observations that demonstrate how the deformation of millimetric cavitation bubbles by a uniform pressure gradient quenches single-collapse luminescence. Our innovative measurement system captures a broad luminescence spectrum (wavelength range, 300-900 nm) from the individual collapses of laser-induced bubbles in water. By varying the bubble size, driving pressure, and perceived gravity level aboard parabolic flights, we probed the limit from aspherical to highly spherical bubble collapses. Luminescence was detected for bubbles of maximum radii within the previously uncovered range, R0=1.5 -6 mm, for laser-induced bubbles. The relative luminescence energy was found to rapidly decrease as a function of the bubble asymmetry quantified by the anisotropy parameter ζ , which is the dimensionless equivalent of the Kelvin impulse. As established previously, ζ also dictates the characteristic parameters of bubble-driven microjets. The threshold of ζ beyond which no luminescence is observed in our experiment closely coincides with the threshold where the microjets visibly pierce the bubble and drive a vapor jet during the rebound. The individual fitted blackbody temperatures range between Tlum=7000 and Tlum=11 500 K but do not show any clear trend as a function of ζ . Time-resolved measurements using a high-speed photodetector disclose multiple luminescence events at each bubble collapse. The averaged full width at half-maximum of the pulse is found to scale with R0 and to range between 10 and 20 ns.

  19. Tiber Personal Rapid Transit

    Directory of Open Access Journals (Sweden)

    Diego Carlo D'agostino


    Full Text Available The project “Tiber Personal Rapid Transit” have been presented by the author at the Rome City Vision Competition1 2010, an ideas competition, which challenges architects, engineers, designers, students and creatives individuals to develop visionary urban proposals with the intention of stimulating and supporting the contemporary city, in this case Rome. The Tiber PRT proposal tries to answer the competition questions with the definition of a provocative idea: a Personal Rapid transit System on the Tiber river banks. The project is located in the central section of the Tiber river and aims at the renewal of the river banks with the insertion of a Personal Rapid Transit infrastructure. The project area include the riverbank of Tiber from Rome Transtevere RFI station to Piazza del Popolo, an area where main touristic and leisure attractions are located. The intervention area is actually no used by the city users and residents and constitute itself a strong barrier in the heart of the historic city.

  20. GradientOptimizer: an open-source graphical environment for calculating optimized gradients in reversed-phase liquid chromatography. (United States)

    Moruz, Luminita; Käll, Lukas


    We here present GradientOptimizer, an intuitive, lightweight graphical user interface to design nonlinear gradients for separation of peptides by reversed-phase liquid chromatography. The software allows to calculate three types of nonlinear gradients, each of them optimizing a certain retention time distribution of interest. GradientOptimizer is straightforward to use, requires minimum processing of the input files, and is supported under Windows, Linux, and OS X platforms. The software is open-source and can be downloaded under an Apache 2.0 license at © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Behavioral variability, elimination of responses, and delay-of-reinforcement gradients in SHR and WKY rats

    Directory of Open Access Journals (Sweden)

    Killeen Peter R


    Full Text Available Abstract Background Attention-deficit/hyperactivity disorder (ADHD is characterized by a pattern of inattention, hyperactivity, and impulsivity that is cross-situational, persistent, and produces social and academic impairment. Research has shown that reinforcement processes are altered in ADHD. The dynamic developmental theory has suggested that a steepened delay-of-reinforcement gradient and deficient extinction of behavior produce behavioral symptoms of ADHD and increased behavioral variability. Method The present study investigated behavioral variability and elimination of non-target responses during acquisition in an animal model of ADHD, the spontaneously hypertensive rat (SHR, using Wistar Kyoto (WKY rats as controls. The study also aimed at providing a novel approach to measuring delay-of-reinforcement gradients in the SHR and the WKY strains. The animals were tested in a modified operant chamber presenting 20 response alternatives. Nose pokes in a target hole produced water according to fixed interval (FI schedules of reinforcement, while nose pokes in the remaining 19 holes either had no consequences or produced a sound or a short flickering of the houselight. The stimulus-producing holes were included to test whether light and sound act as sensory reinforcers in SHR. Data from the first six sessions testing FI 1 s were used for calculation of the initial distribution of responses. Additionally, Euclidean distance (measured from the center of each hole to the center of the target hole and entropy (a measure of variability were also calculated. Delay-of-reinforcement gradients were calculated across sessions by dividing the fixed interval into epochs and determining how much reinforcement of responses in one epoch contributed to responding in the next interval. Results Over the initial six sessions, behavior became clustered around the target hole. There was greater initial variability in SHR behavior, and slower elimination of

  2. Integration and reuse in cognitive skill acquisition. (United States)

    Salvucci, Dario D


    Previous accounts of cognitive skill acquisition have demonstrated how procedural knowledge can be obtained and transformed over time into skilled task performance. This article focuses on a complementary aspect of skill acquisition, namely the integration and reuse of previously known component skills. The article posits that, in addition to mechanisms that proceduralize knowledge into more efficient forms, skill acquisition requires tight integration of newly acquired knowledge and previously learned knowledge. Skill acquisition also benefits from reuse of existing knowledge across disparate task domains, relying on indexicals to reference and share necessary information across knowledge components. To demonstrate these ideas, the article proposes a computational model of skill acquisition from instructions focused on integration and reuse, and applies this model to account for behavior across seven task domains. Copyright © 2013 Cognitive Science Society, Inc.

  3. Merging Platform Ecosystems in Technology Acquisitions

    DEFF Research Database (Denmark)

    Dowie, Jamie; Henningsson, Stefan; Kude, Thomas


    of the merging companies. Given the increasing importance of platforms and value co-creation with third-party providers for companies making technology acquisitions, we complement existing literature by reframing the analysis of technology acquisitions to include the merger of the broader partner ecosystems....... Specifically, we draw on theories of ecosystem governance to analyze how ecosystem tensions unfolded during the ecosystem merger and how the acquirer governed these tensions in SAP SE’s acquisition of the e-commerce provider Hybris AG. Our findings suggest that the governance of ecosystem tensions...... is an important aspect of managing technology acquisitions. We identify the pre-acquisition relation between the acquired company’s ecosystem partners and the acquirer as an important context factor for explaining how a partner company is exposed to the ecosystem tensions during the merger....

  4. Risks of Mergers and Acquisitions Processes

    Directory of Open Access Journals (Sweden)

    Skitsko Volodymyr I.


    Full Text Available Despite structural changes both in the economies of individual countries and in the world at large, the size of the merger/acquisition market is not declining and is tending to grow further. However, uncertainty in the global environment increases the importance of proper analysis, assessment and risk management in merger/acquisition transactions. Using the relevant research and publications by various authors, we have built a general ranking of the significance of merger and acquisition risks according to phases of the indicated process, with comparison of individual risk ratings, based on the publications by authors from Central and Eastern Europe and other countries around the world. The ranking of risks and threats of mergers/acquisitions proposed in this work can be considered one of the most complete for today. Further research needs to focus on the analysis, evaluation, and modeling of merger/acquisition risks, which occupy the top of the ranking, presented by the article.

  5. IT Consultants in Acquisition IT Integration

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Øhrgaard, Christian


    strategic IT initiatives and how companies can draw effectively on their services. The paper investigates the use of consultants in relation to one type of major strategic IT initiative: acquisition IT integration. Acquisition IT integration, which is the integration of the acquirer’s and target......’s IT following a corporate acquisition, presents a difficult but crucial IT challenge for the many acquiring organizations. Through a comparative case study of four acquirers, theoretically grounded in the resource-based view of the firm, it is analyzed how acquirers draw on external consultants to realize...... acquisition IT integration. Two complementary and two supplementary roles consultants assume in these projects are identified. Additionally, three characteristics of the acquisition IT integration strategy are identified that influence how the acquirers assign different roles to IT consultants. The resulting...

  6. An Acquisition Leader’s Model for Building Collaborative Capacity (United States)


    14. SUBJECT TERMS Collaboration, Collaboration Capacity, Defense Acquisition, Acquisition Leader , Program Management , Project Management ...with key stakeholders? 5) How can acquisition leaders manage the “stove piped” acquisition system’s network? D. INFORMED FOUNDATION In...military deputy to the Army Under Secretary of Defense for Acquisition Logistics and Technology who states: A program manager is a leader with a

  7. IT-based Value Creation in Serial Acquisitions

    DEFF Research Database (Denmark)

    Henningsson, Stefan; Yetton, Philip


    The extant research on post-acquisition IT integration analyzes how acquirers realize IT-based value in individual acquisitions. However, serial acquirers make 60% of acquisitions. These acquisitions are not isolated events, but are components in growth-by-acquisition programs. To explain how ser...

  8. Testing for local adaptation and evolutionary potential along altitudinal gradients in rainforest Drosophila: beyond laboratory estimates. (United States)

    O'Brien, Eleanor K; Higgie, Megan; Reynolds, Alan; Hoffmann, Ary A; Bridle, Jon R


    Predicting how species will respond to the rapid climatic changes predicted this century is an urgent task. Species distribution models (SDMs) use the current relationship between environmental variation and species' abundances to predict the effect of future environmental change on their distributions. However, two common assumptions of SDMs are likely to be violated in many cases: (i) that the relationship of environment with abundance or fitness is constant throughout a species' range and will remain so in future and (ii) that abiotic factors (e.g. temperature, humidity) determine species' distributions. We test these assumptions by relating field abundance of the rainforest fruit fly Drosophila birchii to ecological change across gradients that include its low and high altitudinal limits. We then test how such ecological variation affects the fitness of 35 D. birchii families transplanted in 591 cages to sites along two altitudinal gradients, to determine whether genetic variation in fitness responses could facilitate future adaptation to environmental change. Overall, field abundance was highest at cooler, high-altitude sites, and declined towards warmer, low-altitude sites. By contrast, cage fitness (productivity) increased towards warmer, lower-altitude sites, suggesting that biotic interactions (absent from cages) drive ecological limits at warmer margins. In addition, the relationship between environmental variation and abundance varied significantly among gradients, indicating divergence in ecological niche across the species' range. However, there was no evidence for local adaptation within gradients, despite greater productivity of high-altitude than low-altitude populations when families were reared under laboratory conditions. Families also responded similarly to transplantation along gradients, providing no evidence for fitness trade-offs that would favour local adaptation. These findings highlight the importance of (i) measuring genetic variation

  9. A servo controlled gradient loading triaxial model test system for deep-buried cavern

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xu-guang [College of Engineering, Ocean University of China, Qingdao 266100 (China); Shandong Provincial Key Laboratory of Ocean Engineering, Qingdao 266100 (China); Research Center of Geotechnical and Structural Engineering, Shandong University, Jinan 250061 (China); Zhang, Qiang-yong; Li, Shu-cai [Research Center of Geotechnical and Structural Engineering, Shandong University, Jinan 250061 (China)


    A servo controlled gradient loading model test system is developed to simulate the gradient geostress in deep-buried cavern. This system consists of the gradient loading apparatus, the digital servo control device, and the measurement system. Among them, the gradient loading apparatus is the main component which is used for exerting load onto the model. This loading apparatus is placed inside the counterforce wall/beam and is divided to several different loading zones, with each loading zone independently controlled. This design enables the gradient loading. Hence, the “real” geostress field surrounding the deep-buried cavern can be simulated. The loading or unloading process can be controlled by the human-computer interaction machines, i.e., the digital servo control system. It realizes the automation and visualization of model loading/unloading. In addition, this digital servo could control and regulate hydraulic loading instantaneously, which stabilizes the geostress onto the model over a long term. During the loading procedure, the collision between two adjacent loading platens is also eliminated by developing a guide frame. This collision phenomenon is induced by the volume shrinkage of the model when compressed in true 3D state. In addition, several accurate measurements, including the optical and grating-based method, are adopted to monitor the small deformation of the model. Hence, the distortion of the model could be accurately measured. In order to validate the performance of this innovative model test system, a 3D geomechanical test was conducted on a simulated deep-buried underground reservoir. The result shows that the radial convergence increases rapidly with the release of the stress in the reservoir. Moreover, the deformation increases with the increase of the gas production rate. This observation is consistence with field observation in petroleum engineering. The system is therefore capable of testing deep-buried engineering structures.

  10. Observation of Enhanced Hole Extraction in Br Concentration Gradient Perovskite Materials. (United States)

    Kim, Min-Cheol; Kim, Byeong Jo; Son, Dae-Yong; Park, Nam-Gyu; Jung, Hyun Suk; Choi, Mansoo


    Enhancing hole extraction inside the perovskite layer is the key factor for boosting photovoltaic performance. Realization of halide concentration gradient perovskite materials has been expected to exhibit rapid hole extraction due to the precise bandgap tuning. Moreover, a formation of Br-rich region on the tri-iodide perovskite layer is expected to enhance moisture stability without a loss of current density. However, conventional synthetic techniques of perovskite materials such as the solution process have not achieved the realization of halide concentration gradient perovskite materials. In this report, we demonstrate the fabrication of Br concentration gradient mixed halide perovskite materials using a novel and facile halide conversion method based on vaporized hydrobromic acid. Accelerated hole extraction and enhanced lifetime due to Br gradient was verified by observing photoluminescence properties. Through the combination of secondary ion mass spectroscopy and transmission electron microscopy with energy-dispersive X-ray spectroscopy analysis, the diffusion behavior of Br ions in perovskite materials was investigated. The Br-gradient was found to be eventually converted into a homogeneous mixed halide layer after undergoing an intermixing process. Br-substituted perovskite solar cells exhibited a power conversion efficiency of 18.94% due to an increase in open circuit voltage from 1.08 to 1.11 V and an advance in fill-factor from 0.71 to 0.74. Long-term stability was also dramatically enhanced after the conversion process, i.e., the power conversion efficiency of the post-treated device has remained over 97% of the initial value under high humid conditions (40-90%) without any encapsulation for 4 weeks.

  11. Intelligent FPGA Data Acquisition Framework (United States)

    Bai, Yunpeng; Gaisbauer, Dominic; Huber, Stefan; Konorov, Igor; Levit, Dmytro; Steffen, Dominik; Paul, Stephan


    In this paper, we present the field programmable gate arrays (FPGA)-based framework intelligent FPGA data acquisition (IFDAQ), which is used for the development of DAQ systems for detectors in high-energy physics. The framework supports Xilinx FPGA and provides a collection of IP cores written in very high speed integrated circuit hardware description language, which use the common interconnect interface. The IP core library offers functionality required for the development of the full DAQ chain. The library consists of Serializer/Deserializer (SERDES)-based time-to-digital conversion channels, an interface to a multichannel 80-MS/s 10-b analog-digital conversion, data transmission, and synchronization protocol between FPGAs, event builder, and slow control. The functionality is distributed among FPGA modules built in the AMC form factor: front end and data concentrator. This modular design also helps to scale and adapt the DAQ system to the needs of the particular experiment. The first application of the IFDAQ framework is the upgrade of the read-out electronics for the drift chambers and the electromagnetic calorimeters (ECALs) of the COMPASS experiment at CERN. The framework will be presented and discussed in the context of this paper.

  12. Psychological tools for knowledge acquisition (United States)

    Rueter, Henry H.; Olson, Judith Reitman


    Knowledge acquisition is said to be the biggest bottleneck in the development of expert systems. The problem is getting the knowledge out of the expert's head and into a computer. In cognitive psychology, characterizing metal structures and why experts are good at what they do is an important research area. Is there some way that the tools that psychologists have developed to uncover mental structure can be used to benefit knowledge engineers? We think that the way to find out is to browse through the psychologist's toolbox to see what there is in it that might be of use to knowledge engineers. Expert system developers have relied on two standard methods for extracting knowledge from the expert: (1) the knowledge engineer engages in an intense bout of interviews with the expert or experts, or (2) the knowledge engineer becomes an expert himself, relying on introspection to uncover the basis of his own expertise. Unfortunately, these techniques have the difficulty that often the expert himself isn't consciously aware of the basis of his expertise. If the expert himself isn't conscious of how he solves problems, introspection is useless. Cognitive psychology has faced similar problems for many years and has developed exploratory methods that can be used to discover cognitive structure from simple data.

  13. Adaptive microfluidic gradient generator for quantitative chemotaxis experiments (United States)

    Anielski, Alexander; Pfannes, Eva K. B.; Beta, Carsten


    Chemotactic motion in a chemical gradient is an essential cellular function that controls many processes in the living world. For a better understanding and more detailed modelling of the underlying mechanisms of chemotaxis, quantitative investigations in controlled environments are needed. We developed a setup that allows us to separately address the dependencies of the chemotactic motion on the average background concentration and on the gradient steepness of the chemoattractant. In particular, both the background concentration and the gradient steepness can be kept constant at the position of the cell while it moves along in the gradient direction. This is achieved by generating a well-defined chemoattractant gradient using flow photolysis. In this approach, the chemoattractant is released by a light-induced reaction from a caged precursor in a microfluidic flow chamber upstream of the cell. The flow photolysis approach is combined with an automated real-time cell tracker that determines changes in the cell position and triggers movement of the microscope stage such that the cell motion is compensated and the cell remains at the same position in the gradient profile. The gradient profile can be either determined experimentally using a caged fluorescent dye or may be alternatively determined by numerical solutions of the corresponding physical model. To demonstrate the function of this adaptive microfluidic gradient generator, we compare the chemotactic motion of Dictyostelium discoideum cells in a static gradient and in a gradient that adapts to the position of the moving cell.

  14. Ant functional responses along environmental gradients. (United States)

    Arnan, Xavier; Cerdá, Xim; Retana, Javier


    Understanding species distributions and diversity gradients is a central challenge in ecology and requires prior knowledge of the functional traits mediating species' survival under particular environmental conditions. While the functional ecology of plants has been reasonably well explored, much less is known about that of animals. Ants are among the most diverse, abundant and ecologically significant organisms on earth, and they perform a great variety of ecological functions. In this study, we analyse how the functional species traits present in ant communities vary along broad gradients in climate, productivity and vegetation type in the south-western Mediterranean. To this end, we compiled one of the largest animal databases to date: it contains information on 211 local ant communities (including eight climate variables, productivity, and vegetation type) and 124 ant species, for which 10 functional traits are described. We used traits that characterize different dimensions of the ant functional niche with respect to morphology, life history and behaviour at both individual and colony level. We calculated two complementary functional trait community indices ('trait average' and 'trait dissimilarity') for each trait, and we analysed how they varied along the three different gradients using generalized least squares models that accounted for spatial autocorrelation. Our results show that productivity, vegetation type and, to a lesser extent, each climate variable per se might play an important role in shaping the occurrence of functional species traits in ant communities. Among the climate variables, temperature and precipitation seasonality had a much higher influence on functional responses than their mean values, whose effects were almost lacking. Our results suggest that strong relationships might exist between the abiotic environment and the distribution of functional traits among south-western Mediterranean ant communities. This finding indicates that

  15. cultivadas bajo un gradiente de sombra

    Directory of Open Access Journals (Sweden)

    Marco V. Gutiérrez


    Full Text Available Se evaluó el crecimiento de 9 especies de palmas cultivadas bajo un gradiente de sombra producido por mallas de polipropileno negro de 40, 50, 60, 70 y 80% de sombra, más un tratamiento de malla aluminizada de 70%, y uno con plantas a pleno sol. Las especies evaluadas fueron Caryota mitis (cola de pez, Chamaedorea costaricana (pacaya, Chamaedorea tepejilote (tepejilote, Dypsis lutescens (areca, Licuala elegans (licuala, Phoenix roebelenii (fénix, Ptychosperma macarthurii (palma macarthur, Roystonea regia (palma real, y Veitchia merrillii (navideña. Se midió la altura de las plantas, la longitud de las hojas maduras, y el número de hojas cosechadas, durante 5 cosechas por 2 años. En general, la altura de las plantas y la longitud de las hojas fueron menores a 0-40% de sombra, se incrementaron a 50-70%, y decrecieron a 80%. C. mitis, C. tepejilote, L. elegans y P. macarthurii, se comportaron como especies obligadas de sombra y no sobrevivieron a pleno sol. C. costaricana y D. lutescens sobrevivieron a plena exposición solar, y su crecimiento alcanzó valores máximos a 50-60%. P. roebelenii, R. regia, y V. merrillii mostraron un crecimiento reducido a 0-40%, pero éste mejoró bajo los demás niveles de sombra a lo largo del gradiente. En general, 1-2 años es un periodo apropiado para el cultivo de palmas de crecimiento rápido (R. regia, Chamedorea spp., D. lutescens en casas de mallas. Palmas de lento crecimiento (L.elegans pueden permanecer 3-5 años en una casa de sombra. Se discute estrategias para el uso de gradientes de sombra en el tiempo y en el espacio, según la utilidad y los requerimientos de las especies, los requisitos establecidos por el mercado, y el ciclo de producción del material vegetal.

  16. TU-F-CAMPUS-I-04: Head-Only Asymmetric Gradient System Evaluation: ACR Image Quality and Acoustic Noise

    Energy Technology Data Exchange (ETDEWEB)

    Weavers, P; Shu, Y; Tao, S; Bernstein, M [Mayo Clinic, Rochester, Minnesota (United States); Lee, S; Piel, J; Foo, T [GE Global Research, Niskayuna, NY (United States); Mathieu, J-B [GE Healthcare, Florence, SC (Italy)


    Purpose: A high-performance head-only magnetic resonance imaging gradient system with an acquisition volume of 26 cm employing an asymmetric design for the transverse coils has been developed. It is able to reach a magnitude of 85 mT/m at a slew rate of 700 T/m/s, but operated at 80 mT/m and 500 T/m/s for this test. A challenge resulting from this asymmetric design is that the gradient nonlinearly exhibits both odd- and even-ordered terms, and as the full imaging field of view is often used, the nonlinearity is pronounced. The purpose of this work is to show the system can produce clinically useful images after an on-site gradient nonlinearity calibration and correction, and show that acoustic noise levels fall within non-significant risk (NSR) limits for standard clinical pulse sequences. Methods: The head-only gradient system was inserted into a standard 3T wide-bore scanner without acoustic damping. The ACR phantom was scanned in an 8-channel receive-only head coil and the standard American College of Radiology (ACR) MRI quality control (QC) test was performed. Acoustic noise levels were measured for several standard pulse sequences. Results: Images acquired with the head-only gradient system passed all ACR MR image quality tests; Both even and odd-order gradient distortion correction terms were required for the asymmetric gradients to pass. Acoustic noise measurements were within FDA NSR guidelines of 99 dBA (with assumed 20 dBA hearing protection) A-weighted and 140 dB for peak for all but one sequence. Note the gradient system was installed without any shroud or acoustic batting. We expect final system integration to greatly reduce noise experienced by the patient. Conclusion: A high-performance head-only asymmetric gradient system operating at 80 mT/m and 500 T/m/s conforms to FDA acoustic noise limits in all but one case, and passes all the ACR MR image quality control tests. This work was supported in part by the NIH grant 5R01EB010065.

  17. RapidIO as a multi-purpose interconnect (United States)

    Baymani, Simaolhoda; Alexopoulos, Konstantinos; Valat, Sébastien


    RapidIO ( technology is a packet-switched high-performance fabric, which has been under active development since 1997. Originally meant to be a front side bus, it developed into a system level interconnect which is today used in all 4G/LTE base stations world wide. RapidIO is often used in embedded systems that require high reliability, low latency and scalability in a heterogeneous environment - features that are highly interesting for several use cases, such as data analytics and data acquisition (DAQ) networks. We will present the results of evaluating RapidIO in a data analytics environment, from setup to benchmark. Specifically, we will share the experience of running ROOT and Hadoop on top of RapidIO. To demonstrate the multi-purpose characteristics of RapidIO, we will also present the results of investigating RapidIO as a technology for high-speed DAQ networks using a generic multi-protocol event-building emulation tool. In addition we will present lessons learned from implementing native ports of CERN applications to RapidIO.

  18. Rapidly variable relatvistic absorption (United States)

    Parker, M.; Pinto, C.; Fabian, A.; Lohfink, A.; Buisson, D.; Alston, W.; Jiang, J.


    I will present results from the 1.5Ms XMM-Newton observing campaign on the most X-ray variable AGN, IRAS 13224-3809. We find a series of nine absorption lines with a velocity of 0.24c from an ultra-fast outflow. For the first time, we are able to see extremely rapid variability of the UFO features, and can link this to the X-ray variability from the inner accretion disk. We find a clear flux dependence of the outflow features, suggesting that the wind is ionized by increasing X-ray emission.

  19. Rapid prototype and test

    Energy Technology Data Exchange (ETDEWEB)

    Gregory, D.L.; Hansche, B.D.


    In order to support advanced manufacturing, Sandia has acquired the capability to produce plastic prototypes using stereolithography. Currently, these prototypes are used mainly to verify part geometry and ``fit and form`` checks. This project investigates methods for rapidly testing these plastic prototypes, and inferring from prototype test data actual metal part performance and behavior. Performances examined include static load/stress response, and structural dynamic (modal) and vibration behavior. The integration of advanced non-contacting measurement techniques including scanning laser velocimetry, laser holography, and thermoelasticity into testing of these prototypes is described. Photoelastic properties of the epoxy prototypes to reveal full field stress/strain fields are also explored.

  20. Right-Rapid-Rough (United States)

    Lawrence, Craig


    IDEO (pronounced 'eye-dee-oh') is an international design, engineering, and innovation firm that has developed thousands of products and services for clients across a wide range of industries. Its process and culture attracted the attention of academics, businesses, and journalists around the world, and are the subject of a bestselling book, The Art of Innovation by Tom Kelley. One of the keys to IDEO's success is its use of prototyping as a tool for rapid innovation. This story covers some of IDEO's projects, and gives reasons for why they were successful.