931 resultados para Goddard Space Flight Center. Mission Operations and Data Systems Directorate.


Relevância:

100.00% 100.00%

Publicador:

Resumo:

Maltose-binding protein is the periplasmic component of the ABC transporter responsible for the uptake of maltose/maltodextrins. The Xanthomonas axonopodis pv. citri maltose-binding protein MalE has been crystallized at 293 Kusing the hanging-drop vapour-diffusion method. The crystal belonged to the primitive hexagonal space group P6(1)22, with unit-cell parameters a = 123.59, b = 123.59, c = 304.20 angstrom, and contained two molecules in the asymetric unit. It diffracted to 2.24 angstrom resolution.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

P>The determination of normal parameters is an important procedure in the evaluation of the stomatognathic system. We used the surface electromyography standardization protocol described by Ferrario et al. (J Oral Rehabil. 2000;27:33-40, 2006;33:341) to determine reference values of the electromyographic standardized indices for the assessment of muscular symmetry (left and right side, percentage overlapping coefficient, POC), potential lateral displacing components (unbalanced contractile activities of contralateral masseter and temporalis muscles, TC), relative activity (most prevalent pair of masticatory muscles, ATTIV) and total activity (integrated areas of the electromyographic potentials over time, IMPACT) in healthy Brazilian young adults, and the relevant data reproducibility. Electromyography of the right and left masseter and temporalis muscles was performed during maximum teeth clenching in 20 healthy subjects (10 women and 10 men, mean age 23 years, s.d. 3), free from periodontal problems, temporomandibular disorders, oro-facial myofunctional disorder, and with full permanent dentition (28 teeth at least). Data reproducibility was computed for 75% of the sample. The values obtained were POC Temporal (88 center dot 11 +/- 1 center dot 45%), POC masseter (87 center dot 11 +/- 1 center dot 60%), TC (8 center dot 79 +/- 1 center dot 20%), ATTIV (-0 center dot 33 +/- 9 center dot 65%) and IMPACT (110 center dot 40 +/- 23 center dot 69 mu V/mu V center dot s %). There were no statistical differences between test and retest values (P > 0 center dot 05). The Technical Errors of Measurement (TEM) for 50% of subjects assessed during the same session were 1 center dot 5, 1 center dot 39, 1 center dot 06, 3 center dot 83 and 10 center dot 04. For 25% of the subjects assessed after a 6-month interval, the TEM were 0 center dot 80, 1 center dot 03, 0 center dot 73, 12 center dot 70 and 19 center dot 10. For all indices, there was good reproducibility. These electromyographic indices could be used in the assessment of patients with stomatognathic dysfunction.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Objective To evaluate the BI-RADS as a predictive factor of suspicion for malignancy in breast lesions by correlating radiological with histological results and calculating the positive predictive value for categories 3, 4 and 5 in a breast cancer reference center in the city of São Paulo. Materials and Methods Retrospective, analytical and cross-sectional study including 725 patients with mammographic and/or sonographic findings classified as BI-RADS categories 3, 4 and 5 who were referred to the authors' institution to undergo percutaneous biopsy. The tests results were reviewed and the positive predictive value was calculated by means of a specific mathematical equation. Results Positive predictive values found for categories 3, 4 and 5 were respectively the following: 0.74%, 33.08% and 92.95%, for cases submitted to ultrasound-guided biopsy, and 0.00%, 14.90% and 100% for cases submitted to stereotactic biopsy. Conclusion The present study demonstrated high suspicion for malignancy in lesions classified as category 5 and low risk for category 3. As regards category 4, the need for systematic biopsies was observed.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

In general, laboratory activities are costly in terms of time, space, and money. As such, the ability to provide realistically simulated laboratory data that enables students to practice data analysis techniques as a complementary activity would be expected to reduce these costs while opening up very interesting possibilities. In the present work, a novel methodology is presented for design of analytical chemistry instrumental analysis exercises that can be automatically personalized for each student and the results evaluated immediately. The proposed system provides each student with a different set of experimental data generated randomly while satisfying a set of constraints, rather than using data obtained from actual laboratory work. This allows the instructor to provide students with a set of practical problems to complement their regular laboratory work along with the corresponding feedback provided by the system's automatic evaluation process. To this end, the Goodle Grading Management System (GMS), an innovative web-based educational tool for automating the collection and assessment of practical exercises for engineering and scientific courses, was developed. The proposed methodology takes full advantage of the Goodle GMS fusion code architecture. The design of a particular exercise is provided ad hoc by the instructor and requires basic Matlab knowledge. The system has been employed with satisfactory results in several university courses. To demonstrate the automatic evaluation process, three exercises are presented in detail. The first exercise involves a linear regression analysis of data and the calculation of the quality parameters of an instrumental analysis method. The second and third exercises address two different comparison tests, a comparison test of the mean and a t-paired test.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Poster at Open Repositories 2014, Helsinki, Finland, June 9-13, 2014

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Digitalization has been predicted to change the future as a growing range of non-routine tasks will be automated, offering new kinds of business models for enterprises. Serviceoriented architecture (SOA) provides a basis for designing and implementing welldefined problems as reusable services, allowing computers to execute them. Serviceoriented design has potential to act as a mediator between IT and human resources, but enterprises struggle with their SOA adoption and lack a linkage between the benefits and costs of services. This thesis studies the phenomenon of service reuse in enterprises, proposing an ontology to link different kinds of services with their role conceptually as a part of the business model. The proposed ontology has been created on the basis of qualitative research conducted in three large enterprises. Service reuse has two roles in enterprises: it enables automated data sharing among human and IT resources, and it may provide cost savings in service development and operations. From a technical viewpoint, the ability to define a business problem as a service is one of the key enablers for achieving service reuse. The research proposes two service identification methods, first to identify prospective services in the existing documentation of the enterprise and secondly to model the services from a functional viewpoint, supporting service identification sessions with business stakeholders.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Graffiti, Memory and Contested Space: Mnemonic Initiatives Following Periods of Trauma and/or Repression in Buenos Aires, Argentina This thesis concerns the popular articulation ofmemory following periods or incidents of trauma in Argentina. I am interested in how groups lay claim to various public spaces in the city and how they convert these spaces into mnemonic battlegrounds. In considering these spaces of trauma and places of memory, I am primarily interested in how graffiti writing (stencils, spray-paint, signatures, etchings, wall-paintings, murals and installations) is used to make these spaces transmit particular memories that impugn official versions of the past. This thesis draws on literatures focused on popular/public memory. Scholars argue that memory is socially constructed and thus actively contested. Marginal initiatives such as graffiti writing challenge the memory projects of the state as well as state projects that are perceived by citizens to be 'inadequate,' 'inappropriate,' and/or as promoting the erasure of memory. Many of these initiatives are a reaction to the proreconciliation and pro-oblivion strategies of previous governments. I outline that the history of silences and impunity, and a longstanding emphasis on reconciliation at the expense of truth and justice has created an environment of vulnerable memory in Argentina. Popular memory entrepreneurs react by aggressively articulating their memories in time and in space. As a result of this intense memory work, the built landscape in Buenos Aires is dotted with mnemonic initiatives that aim to contradict or subvert officially sanctioned memories. I also suggest that memory workers in Argentina persistently and carefially use the sites of trauma as well as key public spaces to ensure official as well as popular audiences . The data for this project was collected in five spaces in Buenos Aires, the Plaza de Mayo, Plaza Congreso, La Republica Cromanon nightclub, Avellaneda Train Station and El Olimpo, a former detention centre from the military dictatorship.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Once unit-cell dimensions have been determined from a powder diffraction data set and therefore the crystal system is known (e.g. orthorhombic), the method presented by Markvardsen, David, Johnson & Shankland [Acta Cryst. (2001), A57, 47-54] can be used to generate a table ranking the extinction symbols of the given crystal system according to probability. Markvardsen et al. tested a computer program (ExtSym) implementing the method against Pawley refinement outputs generated using the TF12LS program [David, Ibberson & Matthewman (1992). Report RAL-92-032. Rutherford Appleton Laboratory, Chilton, Didcot, Oxon, UK]. Here, it is shown that ExtSym can be used successfully with many well known powder diffraction analysis packages, namely DASH [David, Shankland, van de Streek, Pidcock, Motherwell & Cole (2006). J. Appl. Cryst. 39, 910-915], FullProf [Rodriguez-Carvajal (1993). Physica B, 192, 55-69], GSAS [Larson & Von Dreele (1994). Report LAUR 86-748. Los Alamos National Laboratory, New Mexico, USA], PRODD [Wright (2004). Z. Kristallogr. 219, 1-11] and TOPAS [Coelho (2003). Bruker AXS GmbH, Karlsruhe, Germany]. In addition, a precise description of the optimal input for ExtSym is given to enable other software packages to interface with ExtSym and to allow the improvement/modification of existing interfacing scripts. ExtSym takes as input the powder data in the form of integrated intensities and error estimates for these intensities. The output returned by ExtSym is demonstrated to be strongly dependent on the accuracy of these error estimates and the reason for this is explained. ExtSym is tested against a wide range of data sets, confirming the algorithm to be very successful at ranking the published extinction symbol as the most likely. (C) 2008 International Union of Crystallography Printed in Singapore - all rights reserved.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Infrared filters and coatings have been employed on many sensing radiometer instruments to measure the thermal emission profiles and concentrations of certian chemical constituents found in planetary atmospheres. The High Resolution Dynamics Limb Sounder ( HIRDLS) is an example of the most recent developments in limb-viewing radiometry by employing a cooled focal plane detector array to provide simultaneous multi-channel monitoring of emission from gas and aerosols over an altitude range between 8 - 70 km. The use of spectrally selective cooled detectors in focal plane arrays has simplified the optical layout of radiometers, greatly reducing the number of components in the optical train. this has inevitably led to increased demands for the enviromnetal durability of the focal plane filters because of the need to cut sub-millimeter sizes, whilst maintaining an optimal spectral performance. Additionally the remaining refractive optical elements require antireflection coatings which must cover the entire spectral range of the focal plane array channels, in this case 6 to 18µm, with a minimum of reflection and absorption. This paper describes the optical layout and spectral design requirements for filteriong in the HIRDLS instrument, and reports progress on the manufacturing and testing of the sub-millimetre sized cooled filters. We also report on the spectral and environmental performance of prototype wideband antireflection coatings which satisfy the requirements above.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Infrared optical-multilayer filters and materials were exposed to the space environment of low Earth for a period of nearly six years on the NASA Long Duration Exposure Facility (LDEF) mission. This report describes the effects of that environment on the physical and optical properties of filters and materials used in an experiment designed by the University of reading Infrared multilayer Laboratory. Results of the experiment comprise IR processed spectra both before (1983), and after (1990) exposure, in conjunction with unexposed control samples.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

This report describes the analysis and development of novel tools for the global optimisation of relevant mission design problems. A taxonomy was created for mission design problems, and an empirical analysis of their optimisational complexity performed - it was demonstrated that the use of global optimisation was necessary on most classes and informed the selection of appropriate global algorithms. The selected algorithms were then applied to the di®erent problem classes: Di®erential Evolution was found to be the most e±cient. Considering the speci¯c problem of multiple gravity assist trajectory design, a search space pruning algorithm was developed that displays both polynomial time and space complexity. Empirically, this was shown to typically achieve search space reductions of greater than six orders of magnitude, thus reducing signi¯cantly the complexity of the subsequent optimisation. The algorithm was fully implemented in a software package that allows simple visualisation of high-dimensional search spaces, and e®ective optimisation over the reduced search bounds.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

Monte Carlo simulations of liquid formamide, N-methylformamide (MF), and N,N-dimethylformamide (DMF) have been performed in the isothermal and isobaric ensemble at 298 K and 1 atm, aiming to investigate the C-H ... O and N-H ... O hydrogen bonds. The interaction energy was calculated using the classical 6-12 Lennard-Jones pairwise potential plus a Coulomb term on a rigid six-site molecular model with the potential parameters being optimized in this work. Theoretical values obtained for heat of vaporization and liquid densities are in good agreement with the experimental data. The radial distribution function [RDF, g(r)] obtained compare well with R-X diffraction data available. The RDF and molecular mechanics (MM2) minimization show that the C-H ... O interaction has a significant role in the structure of the three liquids. These results are supported by ab initio calculations. This Interaction is particularly important in the structure of MF. The intensity of the N-H ... O hydrogen bond is greater in the MF than formamide. This could explain some anomalous properties verified in MF. (C) 1997 John Wiley & Sons, Inc.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The purpose of this study is to assess the relation between the speaking space of the /s/ sound and the freeway space in two subject groups. One group had natural dentition (Group I, n = 61) and the other comprised complete denture wearers (Group II, n = 33). The analysis was done by means of a jaw-tracking device (K6-I Diagnostic System, Myotronics Research Inc., Seattle, WA, USA). Freeway space was determined by asking the subjects to occlude from the postural rest position. Speaking space of /s/ was measured during the pronunciation of the word seis and comprised the mean distance from the /s/ speaking position to maximal intercuspation. A weak correlation was found between the speaking space of /s/ and the freeway space in Group I (r = 0.41, p < 0.01), but in Group II, the correlation was stronger (r = 0.75, p < 0.01). The speaking space of /s/ and freeway space were different in Group I, but statistically similar in Group II (paired t-test, alpha = 0.05). It can be suggested that anatomic changes following prosthetic procedures caused a functional adaptation which resulted in more similar values for the speaking space of /s/ and the freeway space.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

We have searched for young star-forming regions around the merger remnant NGC 2782. By using Galaxy Evolution Explorer far-ultraviolet and near-ultraviolet imaging and H i data we found seven ultraviolet sources, located at distances greater than 26 kpc from the centre of NGC 2782, and coinciding with its western H i tidal tail. These regions were resolved in several smaller systems when Gemini/Gemini multi-object spectrograph (GMOS) r-band images were used. We compared the observed colours to stellar population synthesis models and found that these objects have ages of similar to 1 to 11 Myr and masses ranging from 103.9 to 104.6 M circle dot. By using Gemini/GMOS spectroscopic data we confirm memberships and derive high metallicities for three of the young regions in the tail (12+log(O/H) = 8.74 +/- 0.20, 8.81 +/- 0.20 and 8.78 +/- 0.20). These metallicities are similar to the value presented by the nuclear region of NGC 2782 and also similar to the value presented for an object located close to the main body of NGC 2782. The high metallicities measured for the star-forming regions in the gaseous tidal tail of NGC 2782 could be explained if they were formed out of highly enriched gas which was once expelled from the centre of the merging galaxies when the system collided. An additional possibility is that the tail has been a nursery of a few generations of young stellar systems which ultimately polluted this medium with metals, further enriching the already pre-enriched gas ejected to the tail when the galaxies collided.

Relevância:

100.00% 100.00%

Publicador:

Resumo:

The synthesis of a novel bicyclo-thymidine nucleoside bearing an ester functionality at C(6') (bc(alpha-alk)-nucleosides) is reported. This nucleoside was incorporated into oligodeoxynucleotides via solid phase phosphoramidite chemistry, and the ester moiety was post-synthetically converted to an amide or a carboxy group, or was left unchanged. Thermal melting data (T-m) with complementary DNA and RNA were collected and compared to natural DNA and to bc- and bc(ox)-DNA. It was found that single incorporations of bc(alpha-alk)-nucleosides in DNA duplexes were destabilizing by 0.5 to 2.5 degrees C/mod, whereas two consecutive bc(alpha-alk)-residues were less destabilizing, and in some cases even stabilizing by 0.5 degrees C/mod. In duplexes with complementary RNA, isolated bc(alpha-alk)-residues destabilized the duplex by -1.0 to -4.0 degrees C/mod, depending on the chemical nature of the substituent, whereas two consecutive modifications were only destabilizing by 0.3-1.0 degrees C/mod. The pairing selectivity was similar to that of unmodified or bc-DNA.