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Articles de revues sur le sujet « Low Background systems »

Auteur : Grafiati
Publié le 9 mars 2023
Mis à jour le 10 mars 2023

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1

Miley, H. S., R. L. Brodzinski et J. H. Reeves. « Low-background counting systems compared ». Journal of Radioanalytical and Nuclear Chemistry Articles 160, no 2 (juillet 1992) : 371–85. http://dx.doi.org/10.1007/bf02037112.

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Nevinskii, I. O., et T. V. Tsvetkova. « Variations in a ? background in underground low-background systems ». Atomic Energy 72, no 6 (juin 1992) : 543–45. http://dx.doi.org/10.1007/bf00760915.

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Wójcik, M., et G. Zuzel. « Low-222Rn nitrogen gas generator for ultra-low background counting systems ». Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment 539, no 1-2 (février 2005) : 427–32. http://dx.doi.org/10.1016/j.nima.2004.10.023.

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Loosli, H. H., Markus Forster et R. L. Otlet. « Background Measurements with Different Shielding and Anticoincidence Systems ». Radiocarbon 28, no 2A (1986) : 615–22. http://dx.doi.org/10.1017/s0033822200007803.

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Extremely low background count rates are a necessary condition for both the measurement of 39Ar concentrations in ground and ocean water and of 14C activities in small samples using gas proportional counting techniques. A systematic comparison of the performance of three different designs of shielding systems in four different installations has been made.Background values of selected gas proportional counters were measured, compared and separated into their various components. Acceptably low backgrounds were obtained in all the systems tried. The performance of a NaI shield in a surface laboratory was found to be at least equal to the best obtained with a gas anticoincidence detector in a deep underground laboratory.
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Barton, J. C. « A comparison of sodium iodide and germanium low background counting systems ». Journal of Physics G : Nuclear and Particle Physics 17, S (1 décembre 1991) : S415—S418. http://dx.doi.org/10.1088/0954-3899/17/s/042.

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Jovančević, N., M. Krmar, D. Mrda, J. Slivka et I. Bikit. « Neutron induced background gamma activity in low-level Ge-spectroscopy systems ». Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment 612, no 2 (janvier 2010) : 303–8. http://dx.doi.org/10.1016/j.nima.2009.10.059.

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Theodórsson, Páll. « Quantifying Background Components of Low-Level Gas Proportional Counters ». Radiocarbon 34, no 3 (1992) : 420–27. http://dx.doi.org/10.1017/s0033822200063633.

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I discuss background components of low-level gas proportional counters and show how each component can be estimated based on available data. For more reliable background analysis, further studies are suggested. Based on new information, a generation of low-level gas proportional counting systems for radiocarbon dating may emerge with lower and more predictable background.
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SAKURAI, Hirohisa. « An Application of 14C Measurement Using Low Background Liquid Scintillation Counting Systems ». RADIOISOTOPES 61, no 2 (2012) : 87–93. http://dx.doi.org/10.3769/radioisotopes.61.87.

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Galatanu, N., S. Rodrigues, P. Panine et P. Hoghoj. « More flux, less background : improvements in low power X-ray beam delivery systems ». Acta Crystallographica Section A Foundations of Crystallography 67, a1 (22 août 2011) : C556. http://dx.doi.org/10.1107/s0108767311085928.

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Garg, Kratika, Nirmala Ramakrishnan, Alok Prakash et Thambipillai Srikanthan. « Rapid and Robust Background Modeling Technique for Low-Cost Road Traffic Surveillance Systems ». IEEE Transactions on Intelligent Transportation Systems 21, no 5 (mai 2020) : 2204–15. http://dx.doi.org/10.1109/tits.2019.2917560.

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Calvo-Gallego, Elisa, Piedad Brox et Santiago Sánchez-Solano. « Low-cost dedicated hardware IP modules for background subtraction in embedded vision systems ». Journal of Real-Time Image Processing 12, no 4 (10 octobre 2014) : 681–95. http://dx.doi.org/10.1007/s11554-014-0455-5.

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Pan, Hongpeng, Guofeng Zhu, Chengbin Peng et Qing Xiao. « Background subtraction for night videos ». PeerJ Computer Science 7 (10 juin 2021) : e592. http://dx.doi.org/10.7717/peerj-cs.592.

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Motion analysis is important in video surveillance systems and background subtraction is useful for moving object detection in such systems. However, most of the existing background subtraction methods do not work well for surveillance systems in the evening because objects are usually dark and reflected light is usually strong. To resolve these issues, we propose a framework that utilizes a Weber contrast descriptor, a texture feature extractor, and a light detection unit, to extract the features of foreground objects. We propose a local pattern enhancement method. For the light detection unit, our method utilizes the finding that lighted areas in the evening usually have a low saturation in hue-saturation-value and hue-saturation-lightness color spaces. Finally, we update the background model and the foreground objects in the framework. This approach is able to improve foreground object detection in night videos, which do not need a large data set for pre-training.
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Hult, M., J. Gasparro, P. Lindahl, G. Marissens, A. Fessler et Peter N. Johnston. « On the use of mercury as a means of locating background sources in ultra low-background HPGe-detector systems ». Applied Radiation and Isotopes 66, no 6-7 (juin 2008) : 829–34. http://dx.doi.org/10.1016/j.apradiso.2008.02.021.

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Azmat, Shoaib, Linda Wills et Scott Wills. « Parallelizing Multimodal Background Modeling on a Low-Power Integrated GPU ». Journal of Signal Processing Systems 88, no 1 (13 février 2016) : 43–53. http://dx.doi.org/10.1007/s11265-016-1111-z.

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Theodórsson, Pall. « Radiometric 14C Dating : New Background Analysis, Basis of Improved Systems ». Radiocarbon 40, no 1 (1997) : 157–66. http://dx.doi.org/10.1017/s0033822200018002.

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A recent broad study of the background of all types of low-level beta and gamma detectors has now made it possible to analyze its components more reliably and with greater detail. This general analysis is developed further here for gas proportional and liquid scintillation counters used in radiocarbon dating. The background of gas counters, which is dominated by secondary cosmic gamma radiation, is now well understood and can be described quantitatively. The background of liquid counters is less well understood and can only be described semiquantitatively, its analysis resting partly on estimates. Methods to reduce the background of both types of systems are described and their effectiveness discussed. This analysis may help in evaluating the quality of existing systems as well as in designing better ones.
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Han, Liang, Mingming Liu, Deyong Ye, Ning Zhang, Ed Lim, Jing Lu et Chen Jiang. « Tumor cell membrane-targeting pH-dependent electron donor-acceptor fluorescence systems with low background signals ». Biomaterials 35, no 9 (mars 2014) : 2952–60. http://dx.doi.org/10.1016/j.biomaterials.2013.12.020.

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URITSKY, VADIM M., et NATALIA I. MUZALEVSKAYA. « FRACTAL STOCHASTIC ELECTROMAGNETIC BACKGROUND AS A FACTOR STABILIZING PROCESSES OF VITAL ACTIVITY ». Fractals 01, no 03 (septembre 1993) : 321–25. http://dx.doi.org/10.1142/s0218348x93000344.

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The linkage between functional status of living systems and scale organization of environmental low-frequency fluctuations is studied and shown to be possible only for influences transferring biologically significant information. Fundamental relict form of such influences is background weak energy electromagnetic field. It is demonstrated experimentally that physiologically normal state is supported by scale-invariant (fractal) electromagnetic fluctuations with 1/f spectrum, which have pronounced stabilizing effect on homeostasis and can act as a powerful therapeutic agent. On the contrary, distortion of fractal structure of the background, i.e., during geomagnetic storms, is a destabilizing and pathogenic factor. Primary response of living systems to fractal electromagnetic background appears as restoration and support of self-similarity of endogenic low-frequency fluctuations. Vitally important interaction of living systems with fractal fluctuations of non-living environment is called fractal stochastic coupling.
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Mu, Eveline, Laila Hugrass et David P. Crewther. « Red background facilitates low spatial frequency fearful face processing in groups with high autistic tendency ». Journal of Vision 19, no 10 (6 septembre 2019) : 24d. http://dx.doi.org/10.1167/19.10.24d.

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Tomic, S., T. Vuletic, M. Pinteric et B. Korin-Hamzic. « Modalities of self-organized charge response in low dimensional systems ». Journal de Physique IV 12, no 9 (novembre 2002) : 211–14. http://dx.doi.org/10.1051/jp4:20020397.

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We present modalities of self-organized charge response in low dimensional systems, like diverse organic and quantum spin systems, studied by the low-frequency (10 mHz – 1 MHz) dielectric spectroscopy. Density wave structures with the order of commensurability N = 4 can be recognized as phasons in a random impurity potential, whereas those with N = 3 can be viewed as topological defects like charge domain wall pairs in the background domain structure.
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CIOFI, C., G. GIUSI, G. SCANDURRA et B. NERI. « DEDICATED INSTRUMENTATION FOR HIGH SENSITIVITY, LOW FREQUENCY NOISE MEASUREMENT SYSTEMS ». Fluctuation and Noise Letters 04, no 02 (juin 2004) : L385—L402. http://dx.doi.org/10.1142/s0219477504001963.

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Low Frequency Noise Measurements (LFNM) can be used as very sensitive tool for the characterization of the quality and the reliability of electron devices. However, especially in those cases in which the frequency range of interest extends below 1 Hz, instrumentation with an acceptable low level of background noise is not easily found on the market. In fact, at very low frequencies, the flicker noise introduced by the electronic components which make up the instrumentation becomes predominant and several interesting phenomena which could be detected by means of LFNM may result completely hidden in the background noise. This consideration is not limited to the case of input preamplifiers but does extend to any piece of instrumentation that contributes to the LFNM systems, and in particular to the power supplies used for biasing the Device Under Test. During the last few years, our research groups have been strongly involved in the design of very low noise instrumentation for application in the field of LFNM. In this work we report the main results which we have obtained together with a discussion of the design guidelines that have allowed us, in a few cases, to reach noise levels not to be equalled by any instrumentation available on the market.
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Chiang, Bai-Chiang, et Kevin M. Huffenberger. « Cooling Improves Cosmic Microwave Background Map-making when Low-frequency Noise is Large ». Astrophysical Journal 922, no 2 (24 novembre 2021) : 97. http://dx.doi.org/10.3847/1538-4357/ac31ab.

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Abstract In the context of cosmic microwave background data analysis, we study the solution to the equation that transforms scanning data into a map. As originally suggested in “messenger” methods for solving linear systems, we split the noise covariance into uniform and nonuniform parts and adjust their relative weights during the iterative solution. With simulations, we study mock instrumental data with different noise properties, and find that this “cooling” or perturbative approach is particularly effective when there is significant low-frequency noise in the timestream. In such cases, a conjugate gradient algorithm applied to this modified system converges faster and to a higher fidelity solution than the standard conjugate gradient approach. We give an analytic estimate for the parameter that controls how gradually the linear system should change during the course of the solution.
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Sakai, Winfried. « Music Preferences and Family Language Background ». Journal of Research in Music Education 59, no 2 (9 juin 2011) : 174–95. http://dx.doi.org/10.1177/0022429411406172.

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Turkish migrants are the largest national group in Germany. Nevertheless, neither in music psychology research nor in intercultural research can empirical data on the music preferences of Turkish-German primary schoolchildren in the migrational context be found. This study thus examined the music preference responses of children with Turkish language backgrounds, who were at the end of primary school education, to music examples representing the differences between occidental and oriental music systems. A total of 267 children participated in an investigation in the city of Ludwigshafen am Rhein that involved primary schools that had relatively high and relatively low numbers of children with migrational backgrounds. The data analysis indicated interesting coherences between the children’s family language backgrounds and their music preferences. In the context of migration, however, the children’s responses represented varied possibilities of locating in a local, transnational, or global music culture.
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Klein, Hans-Martin. « Low-Field Magnetic Resonance Imaging ». RöFo - Fortschritte auf dem Gebiet der Röntgenstrahlen und der bildgebenden Verfahren 192, no 06 (12 mai 2020) : 537–48. http://dx.doi.org/10.1055/a-1123-7944.

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Background For more than two decades, the focus of technological progress in MRI was restricted to systems with a field strength of 1.5 T and higher. Low- and mid-field MRI systems, which offer some specific advantages, are vanishing from the market. This article is intended to initiate a re-evaluation of the factor ‘field strength’ in MR imaging. Method Literature review was carried out using MEDLINE database (via Pubmed) over a time span from 1980 to 2019 using free-text and Medical Subject headings (MeSH). Article selection was based on relevance and evidence. Results and Conclusion Low-field MR systems are meanwhile rare in clinical imaging. MRI systems with a lower field strength provide a reduced signal-noise ratio (SNR) and spectral differentiation. However, these systems offer a variety of advantages: Shorter T1 relaxation, better T1 contrast, fewer metal artifacts, reduced susceptibility and chemical shift artifacts, fewer dielectric effects, better tissue penetration, less RF-power deposition, fewer ‘missile effects’, reduced effect on biomedical implants such as shunt valves, less energy and helium consumption. If we free ourselves from the constraints of high-field strength, we are able to offer multiple medical, economic and ecologic advantages to our patients. The development of high-quality low-field MRI is possible and necessary. Key Points: Citation Format
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Ohlemiller, Kevin K., Mary E. Rybak Rice, Allyson D. Rosen, Scott C. Montgomery et Patricia M. Gagnon. « Protection by low-dose kanamycin against noise-induced hearing loss in mice : Dependence on dosing regimen and genetic background ». Hearing Research 280, no 1-2 (octobre 2011) : 141–47. http://dx.doi.org/10.1016/j.heares.2011.05.007.

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KAMANIN, D. V., YU V. PYATKOV, A. N. TYUKAVKIN et YU N. KOPATCH. « EXPERIMENTAL EVIDENCES OF CLUSTERING IN LOW EXCITED HEAVY NUCLEAR SYSTEMS ». International Journal of Modern Physics E 17, no 10 (novembre 2008) : 2250–54. http://dx.doi.org/10.1142/s0218301308011434.

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Results of the experiments aimed at revealing of manifestations of collinear cluster tri-partition (CCT) of the 252 Cf and 236 U * nuclei are reported. Presumably, the ternary decay of nuclear molecules based on heavy magic clusters such as isotopes of Ni , Ge , Sn , Te gives rise to the effect observed. Experimental conditions allow one to distinguish two CCT partners flying almost in the same direction, while analysis of their charges ensures the discrimination of the background due to scattering. A total yield of the CCT originated events found at the order of 10-3 per binary fission.
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Pigati, Jeffrey S., Jay Quade, Jim Wilson, A. J. Timothy Jull et Nathaniel A. Lifton. « Development of low-background vacuum extraction and graphitization systems for 14C dating of old (40–60ka) samples ». Quaternary International 166, no 1 (mai 2007) : 4–14. http://dx.doi.org/10.1016/j.quaint.2006.12.006.

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Hunt, Kieran M. R., et Andrew G. Turner. « Non-linear intensification of monsoon low-pressure systems by the BSISO ». Weather and Climate Dynamics 3, no 4 (18 novembre 2022) : 1341–58. http://dx.doi.org/10.5194/wcd-3-1341-2022.

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Abstract. More than half of the rainfall brought to the Indian subcontinent by the summer monsoon is associated with low-pressure systems (LPSs). Yet their relationship with the boreal summer intraseasonal oscillation (BSISO) – the dominant intraseasonal forcing on the monsoon – is only superficially understood. Using reanalysis data, we explore the relationship between the BSISO and LPS intensity, propagation and precipitation, and associated underlying mechanisms. The BSISO has a large impact on mean monsoon vorticity and rainfall as it moves northward – maximising both in phases 2–3 over southern India and phases 5–6 over northern India – but a much weaker relationship with total column water vapour. We present evidence that LPS genesis also preferentially follows these phases of the BSISO. We identify significant relationships between BSISO phase and LPS precipitation and propagation: for example, during BSISO phase 5, LPSs over northern India produce 51 % heavier rainfall and propagate northwestward 20 % more quickly. Using a combination of moisture flux linearisation and quasi-geostrophic theory, we show that these relationships are driven by changes to the underlying dynamics rather than the moisture content or thermodynamic structure of the monsoon. Using the example of LPSs over northern India during BSISO phase 5, we show that the vertical structure of anomalous vorticity can be split into contributions from the BSISO background circulation and the non-linear response of the LPS to anomalous BSISO circulation. Complementary hypotheses emerge about the source of this non-linear vorticity response: non-linear frictional convergence and secondary barotropic growth. We show that both are important. The BSISO imparts greater meridional shear on the background state, supporting LPS intensification. The BSISO background and non-linear LPS response both contribute significantly to anomalous boundary layer convergence, and we show through vortex budget arguments that the former supports additional LPS intensification in boundary layer, while the latter supports faster westward propagation. This work therefore yields important insights into the scale interactions controlling one of the dominant synoptic systems contributing to rainfall during the monsoon.
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Oftedal, Per. « A holistic view of low-level radiation effects in biological systems ». Canadian Journal of Physics 68, no 9 (1 septembre 1990) : 974–78. http://dx.doi.org/10.1139/p90-139.

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Living organisms have been exposed to background radiation during all their evolution. Repair systems suited to counteract the inflicted damage have developed. It is hypothesized that the level of background radiation is "sensed" by organisms via the low-energy thermalized part of the absorbed energy, thus allowing for long-term "pre-emptive" adjustment of inducible repair capacity. The high-energy (> 100 eV) absorption events cause damage that must be accommodated post hoc by means of stabilizing elements (heat-shock proteins?) and subsequent palliative or restorative repair. The complexity of the reactions and interactions may lead to nonhomogeneous dose–effect curves in the low-dose range. The analysis is developed and discussed on the basis of experimental and epidemiological data that are informative in this context. Dose rates of 0.25 mGy/day and less appear to cause little change in repair capacity. Acute doses of 4 mGy and higher lead to increased repair. Acute doses of up to 250 mGy cause abruptly increasing damage with dose. A plateau of damage, independent of doses in the range following the abrupt increase, indicates a prompt stabilization of damage and subsequent repair. Thus, the reaction pattern is influenced by dose, dose rate, and radiation quality, as well as biological factors.
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Nakamura, Shinji. « Effects of Background Stimulation upon Eye-Movement Information ». Perceptual and Motor Skills 82, no 2 (avril 1996) : 627–35. http://dx.doi.org/10.2466/pms.1996.82.2.627.

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To investigate the effects of background stimulation upon eye-movement information (EMI), the perceived deceleration of the target motion during pursuit eye movement (Aubert-Fleishl paradox) was analyzed. In the experiment, a striped pattern was used as a background stimulus with various brightness contrasts and spatial frequencies for serially manipulating the attributions of the background stimulus. Analysis showed that the retinal-image motion of the background stimulus (optic flow) affected eye-movement information and that the effects of optic flow became stronger when high contrast and low spatial frequency stripes were presented as the background stimulus. In conclusion, optic flow is one source of eye-movement information in determining real object motion, and the effectiveness of optic flow depends on the attributes of the background stimulus.
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Griffiths, Alexander, Johannes Herrnsdorf, Christopher Lowe, Malcolm Macdonald, Robert Henderson, Michael Strain et Martin Dawson. « Temporal Encoding to Reject Background Signals in a Low Complexity, Photon Counting Communication Link ». Materials 11, no 9 (9 septembre 2018) : 1671. http://dx.doi.org/10.3390/ma11091671.

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Communicating information at the few photon level typically requires some complexity in the transmitter or receiver in order to operate in the presence of noise. This in turn incurs expense in the necessary spatial volume and power consumption of the system. In this work, we present a self-synchronised free-space optical communications system based on simple, compact and low power consumption semiconductor devices. A temporal encoding method, implemented using a gallium nitride micro-LED source and a silicon single photon avalanche photo-detector (SPAD), demonstrates data transmission at rates up to 100 kb/s for 8.25 pW received power, corresponding to 27 photons per bit. Furthermore, the signals can be decoded in the presence of both constant and modulated background noise at levels significantly exceeding the signal power. The system’s low power consumption and modest electronics requirements are demonstrated by employing it as a communications channel between two nano-satellite simulator systems.
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Parshin, Alexander, et Yury Parshin. « Optimal signal processing algorithm at the background of non-Gaussian flicker noise ». ITM Web of Conferences 30 (2019) : 04016. http://dx.doi.org/10.1051/itmconf/20193004016.

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The problem of receiving and processing ultra-low-power signals of information transmission systems is being solved. High requirements for energy efficiency on the one hand and a low information transfer rate allows the use of signals with a small spectrum width, including flicker noise spectral regions. A non-Gaussian flicker noise model is used based on a stochastic differential equation with a nonlinear drift coefficient. An optimal signal processing algorithm is being developed against the background of the sum of flicker noise and thermal noise based on an estimated-correlation-compensation approach. The analysis of the effectiveness of optimal signal processing against a background of non-Gaussian flicker noise and thermal noise is carried out.
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Lampe, Nathanael, David G. Biron, Jeremy M. C. Brown, Sébastien Incerti, Pierre Marin, Lydia Maigne, David Sarramia, Hervé Seznec et Vincent Breton. « Simulating the Impact of the Natural Radiation Background on Bacterial Systems : Implications for Very Low Radiation Biological Experiments ». PLOS ONE 11, no 11 (16 novembre 2016) : e0166364. http://dx.doi.org/10.1371/journal.pone.0166364.

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Weber, Heike, Burkhart Fischer, Michael Bach et Franz Aiple. « Occurrence of express saccades under isoluminance and low contrast luminance conditions ». Visual Neuroscience 7, no 5 (novembre 1991) : 505–10. http://dx.doi.org/10.1017/s0952523800009792.

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AbstractSaccadic reaction times (SRTs) of three human subjects were analyzed. The gap paradigm was used (i.e. fixation point offset precedes target onset) to obtain high proportions of express saccades (i.e. saccades of extremely short reaction times) in the SRT distributions. In one set of experiments, the luminance of the (red) saccade target was varied from brighter to darker than the (green) background including an isoluminance condition. Express saccades were obtained in response to pure color contrast stimuli with about the same frequency and reaction time as to stimuli with both color and luminance contrast. In a second experiment, the luminance contrast of a white target on a white background was lowered below 10%. Again the number of express saccades was not reduced. Thus, in contrast to other perceptual phenomena the visual neural mechanisms underlying the generation of express saccades are not affected by isoluminance nor low contrast luminance.
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Daas, Jesse, Wouter Oosters, Frank Saueressig et Jian Wang. « Asymptotically Safe Gravity-Fermion Systems on Curved Backgrounds ». Universe 7, no 8 (19 août 2021) : 306. http://dx.doi.org/10.3390/universe7080306.

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We set up a consistent background field formalism for studying the renormalization group (RG) flow of gravity coupled to Nf Dirac fermions on maximally symmetric backgrounds. Based on Wetterich’s equation, we perform a detailed study of the resulting fixed point structure in a projection including the Einstein–Hilbert action, the fermion anomalous dimension, and a specific coupling of the fermion bilinears to the spacetime curvature. The latter constitutes a mass-type term that breaks chiral symmetry explicitly. Our analysis identified two infinite families of interacting RG fixed points, which are viable candidates to provide a high-energy completion through the asymptotic safety mechanism. The fixed points exist for all values of Nf outside of a small window situated at low values Nf and become weakly coupled in the large Nf-limit. Symmetry-wise, they correspond to “quasi-chiral” and “non-chiral” fixed points. The former come with enhanced predictive power, fixing one of the couplings via the asymptotic safety condition. Moreover, the interplay of the fixed points allows for cross-overs from the non-chiral to the chiral fixed point, giving a dynamical mechanism for restoring the symmetry approximately at intermediate scales. Our discussion of chiral symmetry breaking effects provides strong indications that the topology of spacetime plays a crucial role when analyzing whether quantum gravity admits light chiral fermions.
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Reddy, Vikas, Conrad Sanderson et Brian C. Lovell. « A Low-Complexity Algorithm for Static Background Estimation from Cluttered Image Sequences in Surveillance Contexts ». EURASIP Journal on Image and Video Processing 2011 (2011) : 1–14. http://dx.doi.org/10.1155/2011/164956.

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Joffe, Michael. « Health, Livelihoods, and Nutrition in Low-Income Rural Systems ». Food and Nutrition Bulletin 28, no 2_suppl2 (juin 2007) : S227—S236. http://dx.doi.org/10.1177/15648265070282s202.

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Background Absolute poverty remains a major challenge: the proportion of the world population living with hunger, food insecurity, and undernutrition has fallen, but the absolute number remains stubbornly large. An even larger number of people have enough to eat but suffer from severe micronutrient deficiencies. Objectives To provide a conceptual framework showing the interdependence of hunger and poverty with ill health among the rural poor. Methods Review of the relevant health, nutrition, agriculture, and economics literature and organization of the findings into a systems framework. Results Economic growth is not a sufficient answer to rural poverty. The predicament of poor households can be represented in terms of a self-reinforcing cycle involving nutrition, health, and productivity. The degree of poverty limits the quantity and quality of food intake. Macro- and micronutrient deficiencies interfere with child growth and development and impair immune function, resulting in a predisposition to infectious diseases. Health status strongly influences the quantity and quality of labor and achieved educational status. The high risk of child mortality prevents households from going through the demographic transition to smaller families and better-educated children. The death of a working adult may be catastrophic for the household. This self-reinforcing cycle means that the beneficial effects of an intervention are propagated around the cycle, potentiating its impact. Each main element—nutrition, health, and productivity—also has numerous other determinants and can be influenced by interventions. Interventions that increase the carrying capacity of the household's environment are likely to be more sustainable than “technical fixes,” such as lifesaving medical treatment. Conclusions The self-reinforcing cycle is likely to be self-perpetuating without outside intervention. For any rural area where poverty reduction is planned, the key bottlenecks need to be identified. This can be done by using a causal diagram, as described in this paper.
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Scandurra, G., C. Ciofi, J. Smulko et H. Wen. « A review of design approaches for the implementation of low-frequency noise measurement systems ». Review of Scientific Instruments 93, no 11 (1 novembre 2022) : 111101. http://dx.doi.org/10.1063/5.0116589.

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Electronic noise has its roots in the fundamental physical interactions between matter and charged particles, carrying information about the phenomena that occur at the microscopic level. Therefore, Low-Frequency Noise Measurements (LFNM) are a well-established technique for the characterization of electron devices and materials and, compared to other techniques, they offer the advantage of being non-destructive and of providing a more detailed view of what happens in the matter during the manifestation of physical or chemical phenomena. For this reason, LFNM acquire particular importance in the modern technological era in which the introduction of new advanced materials requires in-depth and thorough characterization of the conduction phenomena. LFNM also find application in the field of sensors, as they allow to obtain more selective sensing systems even starting from conventional sensors. Performing meaningful noise measurements, however, requires that the background noise introduced by the measurement chain be much smaller than the noise to be detected and the instrumentation available on the market does not always meet the specifications required for reaching the ultimate sensitivity. Researchers willing to perform LFNM must often resort to the design of dedicated instrumentation in their own laboratories, but their cultural background does not necessarily include the ability to design, build, and test dedicated low noise instrumentation. In this review, we have tried to provide as much theoretical and practical guidelines as possible, so that even researchers with a limited background in electronic engineering can find useful information in developing or customizing low noise instrumentation.
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Abrahamsson, Kenneth. « Sustainable work in transition. Policy background, concepts and research arenas ». European Journal of Workplace Innovation 6, no 1 (5 mars 2021) : 19–47. http://dx.doi.org/10.46364/ejwi.v6i1.821.

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Future of work is today discussed at global level in Agenda 2030 and SDG 8, by ILO and in the Global Deal which is a multi-stakeholder initiative for social dialogue and inclusive growth. Future of work, social innovations and inclusive growth are also central policy missions for the OECD, the European Commission, and its agencies Cedefop, EU-OSHA and Eurofound. The European Pillar of Social Rights highlights the need for a European social model promoting a progressive interplay between economic development, god working conditions and social protection. This article analyses concepts of quality of work, decent work, and sustainable work. Its title comprises different connotation of sustainable work in transition. Firstly, sustainable work has not got significant attention in the policy agenda on sustainable development. Secondly, new forms of work and the dissolution of the traditional workplace and standard employment relations call for a widened use of the content of sustainable work. Thirdly, the Green Deal, low carbon omissions and new energy systems will have substantial impact on work organisation and production systems. Finally, digitalization, labour market transformations and increasing job longevity make job shifts and skills upgrading more common and sustainable work must be seen in a life-course and lifelong perspective.
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SCHUBERTH, ERWIN A. « SOME HEAVY FERMION SYSTEMS AT VERY LOW TEMPERATURES ». International Journal of Modern Physics B 10, no 04 (15 février 1996) : 357–98. http://dx.doi.org/10.1142/s0217979296000155.

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The emphasis of this article lies on the properties of heavy fermion systems at the lowest temperatures obtained so far. Methods for measuring specific heat capacity and magnetic susceptibility in the milliKelvin regime are described for both low magnetic fields (<20 mT ) and high fields (<8 T ). Experimental results on UPt 3, UBe 13, and CeCu 6, are presented, and remaining problems are discussed. UPt 3 is widely regarded as the heavy Fermion system which exhibits unconventional superconductivity as demonstrated by the existence of multiple superconducting phases. Whether power laws for instance for the specific heat capacity in the superconducting state extend to T ≈ 0 instead of an exponential behavior as for BCS superconductors is a long-standing question. We have measured the specific heat capacity of several single crystals of UPt 3 in magnetic fields varying from 0 up to 7 T down to a final temperature of 10 mK . Instead of an extended power law a maximum of c(T) occurs around 20 mK, and this maximum persists in magnetic fields above B c2. It is obviously due to a new phase transition which is present both in the normal and in the superconducting state of UPt 3, slightly modified in the latter. Entropy balance above T c is fulfilled if the low-temperature peaks are included. DC-magnetization measurements on two single crystals of UPt 3 in a SQUID system yield a temperature dependence of the penetration depth ~T2 between 150 and 20 mK, considerably extending the temperature range of earlier experiments. Measurements of the anisotropic part of the magnetic susceptibility in a torque-meter indicate an additional phase line from a temperature-dependent anisotropic susceptibility to a T-independent state which is closely connected to the Bc2-line over a wide field range. No indication for a re-entrance of superconductivity is found down to 20 mK. For UBe 13 (in the superconducting state) no specific heat anomaly above 24 mK is found but a deviation from the T2.7 power law valid at higher temperatures. On a single crystal of CeCu 6 dc-magnetization measurements in various magnetic fields in a SQUID system show a plateau of the magnetic susceptibility between 400 and 50 mK, followed by an increase towards lower temperatures. An attempt to fit the low-temperature magnetization curves in several fields between 0.01 mT and 1.6 mT (minus the background from the plateau) with a Brillouin function revealed significant deviations. In 2.7 mT, the highest field applied in this experiment, however, the magnetization can be perfectly fitted assuming a tiny concentration of Gd impurities (1.5 ppm). After subtraction of the contribution due to the Gd 3+ ions from the magnetization curves in each of the lower fields a drop is revealed below 3–5 mK which gets successively quenched by the magnetic field and which has disappeared in 2.7 mT. The specific heat capacity of the same single crystal of CeCu 6 in zero magnetic field shows an increase of c/T from 1.55 J/moleK 2 at higher temperatures up to 2.8 J/moleK 2 at 11 mK. We interpret both results as due to an antiferromagnetic phase transition at 3–5 mK with the peak just not reached in the specific heat experiments.
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Combet, Benita. « The Institutional Dimension of Class-based Educational Decision-making : Evidence from Regional Variation in Switzerland ». Zeitschrift für Soziologie 48, no 4 (1 octobre 2019) : 301–20. http://dx.doi.org/10.1515/zfsoz-2019-0021.

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AbstractThis article examines to what extent the specific institutional arrangement of an education system moderates the influence of social background on students’ track allocation, and whether this happens via primary or secondary effects of social origin. I tackle the problem of omitted-variable bias by analyzing subnational education systems in Switzerland, a country with a variety of cantonal school systems but otherwise homogeneous institutions. The results show a complex picture. First, even though the absolute transition probability to the highest track is higher in education systems with low stratification for students of higher social background, this does not translate into a relative advantage as in most cantons the odds of transitioning do not differ between high and low social background students. Second, in line with previous research, I observe that the secondary effect of social origin prevails in more stratified education systems. Third, it is not possible to conclude with certainty that specific features of the education system enable high social background parents to disproportionately influence their children’s transition probabilities because the results are not robust.
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Schneider, Miroslav, Zdenek Machacek, Radek Martinek, Jiri Koziorek et Rene Jaros. « A System for the Detection of Persons in Intelligent Buildings Using Camera Systems—A Comparative Study ». Sensors 20, no 12 (23 juin 2020) : 3558. http://dx.doi.org/10.3390/s20123558.

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This article deals with the design and implementation of a prototype of an efficient Low-Cost, Low-Power, Low Complexity–hereinafter (L-CPC) an image recognition system for person detection. The developed and presented methods for processing, analyzing and recognition are designed exactly for inbuilt devices (e.g., motion sensor, identification of property and other specific applications), which will comply with the requirements of intelligent building technologies. The paper describes detection methods using a static background, where, during the search for people, the background image field being compared does not change, and a dynamic background, where the background image field is continually adjusted or complemented by objects merging into the background. The results are compared with the output of the Horn-Schunck algorithm applied using the principle of optical flow. The possible objects detected are subsequently stored and evaluated in the actual algorithm described. The detection results, using the change detection methods, are then evaluated using the Saaty method in order to determine the most successful configuration of the entire detection system. Each of the configurations used was also tested on a video sequence divided into a total of 12 story sections, in which the normal activities of people inside the intelligent building were simulated.
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Cheng-Guang, Bao. « Background of Existence of the Two Low-Lying Adjacent 4+ Narrow Resonances in 16O Nucleus and Other 4-Boson Systems ». Chinese Physics Letters 18, no 5 (24 avril 2001) : 638–40. http://dx.doi.org/10.1088/0256-307x/18/5/305.

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KRISCH, MICHAEL, et FRANCESCO SETTE. « X-RAY RAMAN SCATTERING FROM LOW Z MATERIALS ». Surface Review and Letters 09, no 02 (avril 2002) : 969–76. http://dx.doi.org/10.1142/s0218625x02001689.

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X-ray Raman scattering from core electrons of low Z materials provides an alternative to soft X-ray absorption spectroscopy in cases where (i) exotic final states will be probed, (ii) the penetrating power of hard X rays is needed to study bulk properties, and (iii) when systems under high pressure are studied. The theoretical background and experimental requirements are discussed. The present capabilities of the technique are illustrated by two experiments, performed on the inelastic X ray scattering beamlines at the European Synchrotron Radiation Facility.
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Zhang, Jie, Hong Zhang, Bo Yang et Ruizhi Zhang. « Joint background calibration of gain and timing mismatch errors with low hardware cost for time‐interleaved ADCs ». IET Circuits, Devices & ; Systems 13, no 2 (15 février 2019) : 203–10. http://dx.doi.org/10.1049/iet-cds.2018.5194.

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Teichmann, R., et L. Spillmann. « Fading of Textured Targets on Textured Background ». Perception 26, no 1_suppl (août 1997) : 5. http://dx.doi.org/10.1068/v970094.

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In 1804 Troxler reported that with strict fixation, a small, low-contrast target presented to the peripheral visual field will tend to fade and ultimately become invisible. Further studies have shown that, in addition to stationary targets, moving and flickering targets will also fade. We studied the role of a texture difference between the target and its background on fading. We found that textured targets fade as quickly as, or even faster than, uniform targets. Typically, the target becomes less salient and after a while disappears in the background. Specifically, we asked whether orientation contrast would influence the time of perceptual disappearance. A grating disk of 2 deg diameter and 0.8 cycle deg−1 spatial frequency was presented binocularly on an equally striped background, 15 deg from the fixation point. The orientation of the target relative to that of the background was varied in steps of 15°, yielding eleven stimuli which were presented in a random order. Each orientation was shown a total of nine times. Luminance, spatial frequency, and contrast were the same for both the target and the background. Time to fading was measured for each target orientation. The results show that orientation contrast strongly affects fading. Time to fading was longest when the grating target and the background were oriented at right angles and decreased symmetrically with decreasing orientation contrast. This result supports the hypothesis that fading is an active neuronal process of long-range lateral interactions.
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Nuwarda, Rina Fajri, Iqbal Ramzan, Lynn Weekes et Veysel Kayser. « Vaccine Hesitancy : Contemporary Issues and Historical Background ». Vaccines 10, no 10 (22 septembre 2022) : 1595. http://dx.doi.org/10.3390/vaccines10101595.

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Vaccination, despite being recognized as one of the most effective primary public health measures, is viewed as unsafe and unnecessary by an increasing number of individuals. Anxiety about vaccines and vaccination programs leading to vaccine hesitancy results from a complex mix of social and political influences, cultural and religious beliefs, the availability of and ability to interpret health and scientific information, and personal and population experiences of health systems and government policies. Vaccine hesitancy is becoming a serious threat to vaccination programs, and was identified as one of the World Health Organization’s top ten global health threats in 2019. The negative impact of anti-vaccination movements is frequently cited as one of the major reasons for rising vaccine hesitancy amongst the general public world-wide. This review discusses the various issues surrounding vaccine hesitancy and the anti-vaccine movement, starting with the definitions of vaccine hesitancy and the anti-vaccine movement in their early history and in the modern era, before discussing the key drivers of vaccine hesitancy, particularly across different regions of the world, with a focus on various countries with low-, middle-, or high-income economies with different socio-economic populations. The review concludes with the impact of vaccine hesitancy on herd immunity and social, psychological, and public health measures to counter vaccine hesitancy.
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Snippe, H. P., L. Poot et J. H. van Hateren. « Detection Thresholds for Light Pulses Superimposed on Backgrounds with Temporally Modulated Luminance ». Perception 26, no 1_suppl (août 1997) : 360. http://dx.doi.org/10.1068/v970235.

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We investigated the effects of sinusoidal modulation of the luminance of a large (17 deg) spatially homogeneous field on detection thresholds for a brief (7.5 ms) light pulse 46 min arc or 17 deg in size. The average luminance of the background field was at a high photopic level (2800 Td) throughout the experiment. Temporal frequency f (0.4 – 200 Hz) and contrast C (0.05 – 0.8) of the background modulation were varied, together with the timing t of the test pulse in the modulation cycle. As a function of f, thresholds reach maximum around 15 – 20 Hz, and steeply decline at higher frequencies. At frequencies above flicker fusion, thresholds do not depend on t, and are equal to the detection threshold on a constant background with the time-averaged luminance, in accordance with Talbot's law. At frequencies below 15 Hz, threshold elevations above threshold at constant background depend on f as a power law, with a power exponent (0.8 – 1.0) that is close to 1. Also threshold elevation as a function of modulation contrast conforms to a power law, with a similar power exponent (0.8 – 1.0). The effects of t are complex, and depend on both the frequency and the contrast of the background modulation. Our results yield constraints for models of luminance adaptation and contrast masking. In particular, the results at high frequencies indicate that the first stage of such models should consist of a linear low-pass filtering of the input luminance. The results at low frequency suggest a temporal derivative operation of the resulting signal. We discuss to what extent existing models can explain the dynamics of the measurements.
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Tonosaki, Y., P. M. J. M. Cruijsen, K. Nishiyama, H. Yaginuma et E. W. Roubos. « Low Temperature Stimulates alpha-Melanophore-Stimulating Hormone Secretion and Inhibits Background Adaptation in Xenopus laevis ». Journal of Neuroendocrinology 16, no 11 (novembre 2004) : 894–905. http://dx.doi.org/10.1111/j.1365-2826.2004.01247.x.

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Liao, Lida, Bin Huang, Qi Tan, Kan Huang, Mei Ma et Kang Zhang. « Development of an Improved LMD Method for the Low-Frequency Elements Extraction from Turbine Noise Background ». Energies 13, no 4 (12 février 2020) : 805. http://dx.doi.org/10.3390/en13040805.

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Given the prejudicial environmental effects of fossil-fuel based energy production, renewable energy sources can contribute significantly to the sustainability of human society. As a clean, cost effective and inexhaustible renewable energy source, wind energy harvesting has found a wide application to replace conventional energy productions. However, concerns have been raised over the noise generated by turbine operating, which is helpful in fault diagnose but primarily identified for its adverse effects on the local ecosystems. Therefore, noise monitoring and separation is essential in wind turbine deployment. Recent developments in condition monitoring provide a solution for turbine noise and vibration analysis. However, the major component, aerodynamic noise is often distorted in modulation, which consequently affects the condition monitoring. This study is conducted to explore a novel approach to extract low-frequency elements from the aerodynamic noise background, and to improve the efficiency of online monitoring. A framework built on the spline envelope method and improved local mean decomposition has been developed for low-frequency noise extraction, and a case study with real near-field noises generated by a mountain-located wind turbine was employed to validate the proposed approach. Results indicate successful extractions with high resolution and efficiency. Findings of this research are also expected to further support the fault diagnosis and the improvement in condition monitoring of turbine systems.
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Verna, Adriano, Raffaella Capelli et Luca Pasquali. « Resonant Soft X-ray Reflectivity in the Study of Magnetic Properties of Low-Dimensional Systems ». Magnetochemistry 7, no 10 (7 octobre 2021) : 136. http://dx.doi.org/10.3390/magnetochemistry7100136.

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In this review, the technique of resonant soft X-ray reflectivity in the study of magnetic low-dimensional systems is discussed. This technique is particularly appealing in the study of magnetization at buried interfaces and to discriminate single elemental contributions to magnetism, even when this is ascribed to few atoms. The major fields of application are described, including magnetic proximity effects, thin films of transition metals and related oxides, and exchange-bias systems. The fundamental theoretical background leading to dichroism effects in reflectivity is also briefly outlined.
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