Depth of interaction detection with enhanced position-sensitive proportional resistor network

International Nuclear Information System (INIS)

Lerche, Ch.W.; Benlloch, J.M.; Sanchez, F.; Pavon, N.; Gimenez, N.; Fernandez, M.; Gimenez, M.; Sebastia, A.; Martinez, J.; Mora, F.J.

2005-01-01

A new method of determining the depth of interaction of γ-rays in thick inorganic scintillation crystals was tested experimentally. The method uses the strong correlation between the width of the scintillation light distribution within large continuous crystals and the γ-ray's interaction depth. This behavior was successfully reproduced by a theoretical model distribution based on the inverse square law. For the determination of the distribution's width, its standard deviation σ is computed using an enhanced position-sensitive proportional resistor network which is often used in γ-ray-imaging devices. Minor changes of this known resistor network allow the analog and real-time determination of the light distribution's 2nd moment without impairing the measurement of the energy and centroid. First experimental results are presented that confirm that the described method works correctly. Since only some cheap electronic components, but no additional detectors or crystals are required, the main advantage of this method is its low cost

Stress as a mnemonic filter: Interactions between medial temporal lobe encoding processes and post-encoding stress.

Science.gov (United States)

Ritchey, Maureen; McCullough, Andrew M; Ranganath, Charan; Yonelinas, Andrew P

2017-01-01

Acute stress has been shown to modulate memory for recently learned information, an effect attributed to the influence of stress hormones on medial temporal lobe (MTL) consolidation processes. However, little is known about which memories will be affected when stress follows encoding. One possibility is that stress interacts with encoding processes to selectively protect memories that had elicited responses in the hippocampus and amygdala, two MTL structures important for memory formation. There is limited evidence for interactions between encoding processes and consolidation effects in humans, but recent studies of consolidation in rodents have emphasized the importance of encoding "tags" for determining the impact of consolidation manipulations on memory. Here, we used functional magnetic resonance imaging in humans to test the hypothesis that the effects of post-encoding stress depend on MTL processes observed during encoding. We found that changes in stress hormone levels were associated with an increase in the contingency of memory outcomes on hippocampal and amygdala encoding responses. That is, for participants showing high cortisol reactivity, memories became more dependent on MTL activity observed during encoding, thereby shifting the distribution of recollected events toward those that had elicited relatively high activation. Surprisingly, this effect was generally larger for neutral, compared to emotionally negative, memories. The results suggest that stress does not uniformly enhance memory, but instead selectively preserves memories tagged during encoding, effectively acting as mnemonic filter. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Silicon photomultipliers for positron emission tomography detectors with depth of interaction encoding capability

International Nuclear Information System (INIS)

Taghibakhsh, Farhad; Reznik, Alla; Rowlands, John A.

2011-01-01

Silicon photomultipliers (SiPMs) are receiving increasing attention in the field of positron emission tomography (PET) detectors. Compared to photomultiplier tubes, they offer novel detector configurations for the extraction of depth of interaction (DOI) information, or enable emerging medical imaging modalities such as simultaneous PET-magnetic resonant imaging (MRI). In this article, we used 2x2x20 mm 3 LYSO scintillator crystals coupled to SiPMs on both ends (dual-ended readout configuration) to evaluate the detector performance for DOI-PET applications. We investigated the effect of scintillator crystal surface finishing on sensitivity and resolution of DOI, as well as on energy and timing resolution. Measurements indicate DOI sensitivity and resolution of 7.1% mm -1 and 2.1±0.6 mm for saw-cut, and 1.3% mm -1 and 9.0±1.5 mm, for polished scintillator crystals, respectively. Energy resolution varies from 19% when DOI is in the center, to 15% with DOI at either end of the saw-cut crystal, while it remains constant at ∼14% for polished scintillators. Based on our results we conclude that 2x2x20 mm 3 saw-cut (without any special side wall polishing) LYSO crystals coupled to 2x2 mm 2 silicon photomultipliers are optimal for isotropic 2 mm resolution DOI-PET applications.

Left temporal and temporoparietal brain activity depends on depth of word encoding: a magnetoencephalographic study in healthy young subjects.

Science.gov (United States)

Walla, P; Hufnagl, B; Lindinger, G; Imhof, H; Deecke, L; Lang, W

2001-03-01

Using a 143-channel whole-head magnetoencephalograph (MEG) we recorded the temporal changes of brain activity from 26 healthy young subjects (14 females) related to shallow perceptual and deep semantic word encoding. During subsequent recognition tests, the subjects had to recognize the previously encoded words which were interspersed with new words. The resulting mean memory performances across all subjects clearly mirrored the different levels of encoding. The grand averaged event-related fields (ERFs) associated with perceptual and semantic word encoding differed significantly between 200 and 550 ms after stimulus onset mainly over left superior temporal and left superior parietal sensors. Semantic encoding elicited higher brain activity than perceptual encoding. Source localization procedures revealed that neural populations of the left temporal and temporoparietal brain areas showed different activity strengths across the whole group of subjects depending on depth of word encoding. We suggest that the higher brain activity associated with deep encoding as compared to shallow encoding was due to the involvement of more neural systems during the processing of visually presented words. Deep encoding required more energy than shallow encoding but for all that led to a better memory performance. Copyright 2001 Academic Press.

A depth-of-interaction PET detector using mutual gain-equalized silicon photomultiplier

International Nuclear Information System (INIS)

Xi, W.; Weisenberger, A.G.; Dong, H.; Kross, Brian; Lee, S.; McKisson, J.; Zorn, Carl

2012-01-01

We developed a prototype high resolution, high efficiency depth-encoding detector for PET applications based on dual-ended readout of LYSO array with two silicon photomultipliers (SiPMs). Flood images, energy resolution, and depth-of-interaction (DOI) resolution were measured for a LYSO array - 0.7 mm in crystal pitch and 10 mm in thickness - with four unpolished parallel sides. Flood images were obtained such that individual crystal element in the array is resolved. The energy resolution of the entire array was measured to be 33%, while individual crystal pixel elements utilizing the signal from both sides ranged from 23.3% to 27%. By applying a mutual-gain equalization method, a DOI resolution of 2 mm for the crystal array was obtained in the experiments while simulations indicate ∼1 mm DOI resolution could possibly be achieved. The experimental DOI resolution can be further improved by obtaining revised detector supporting electronics with better energy resolutions. This study provides a detailed detector calibration and DOI response characterization of the dual-ended readout SiPM-based PET detectors, which will be important in the design and calibration of a PET scanner in the future.

Cuff depth and continuous chest auscultation method for determination of tracheal tube insertion depth in nasal intubation: observational study.

Science.gov (United States)

Ouchi, Kentaro; Sugiyama, Kazuna

2016-04-01

Incorrect endobronchial placement of the tracheal tube can lead to serious complications. Hence, it is necessary to determine the accuracy of tracheal tube positioning. Markers are included on tracheal tubes, in the process of their manufacture, as indicators of approximate intubation depth. In addition, continuous chest auscultation has been used for determining the proper position of the tube. We examined insertion depth using the cuff depth and continuous chest auscultation method (CC method), compared with insertion depth determined by the marker method, to assess the accuracy of these methods. After induction of anesthesia, tracheal intubation was performed in each patient. In the CC method, the depth of tube insertion was measured when the cuff had passed through the glottis, and again when breath sounds changed in quality; the depth of tube insertion was determined from these values. In the marker method, the depth of tube insertion was measured and determined when the marker of the tube had reached the glottis, using insertion depth according to the marker as an index. Insertion depth by the marker method was 26.6 ± 1.2 cm and by the CC method was 28.0 ± 1.2 cm (P < 0.0001). The CC method indicated a significantly greater depth than the marker method. This study determined the safe range of tracheal tube placement. Tube positions determined by the CC method were about 1 cm deeper than those determined by the marker. This information is important to prevent accidental one-lung ventilation and accidental extubation. UMIN No. UMIN000011375.

Depth of interaction detection for {gamma}-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Lerche, Ch.W. [Instituto de Aplicaciones de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas, (UPV) Camino de Vera s/n, E46022 (Spain)], E-mail: lerche@ific.uv.es; Doering, M. [Institut fuer Kernphysik, Forschungszentrum Juelich GmbH, D52425 Juelich (Germany); Ros, A. [Institute de Fisica Corpuscular (CSIC-UV), 22085, Valencia E46071 (Spain); Herrero, V.; Gadea, R.; Aliaga, R.J.; Colom, R.; Mateo, F.; Monzo, J.M.; Ferrando, N.; Toledo, J.F.; Martinez, J.D.; Sebastia, A. [Instituto de Aplicaciones de las Tecnologias de la Informacion y de las Comunicaciones Avanzadas, (UPV) Camino de Vera s/n, E46022 (Spain); Sanchez, F.; Benlloch, J.M. [Institute de Fisica Corpuscular (CSIC-UV), 22085, Valencia E46071 (Spain)

2009-03-11

A novel design for an inexpensive depth of interaction capable detector for {gamma}-ray imaging has been developed. The design takes advantage of the strong correlation between the width of the scintillation light distribution in monolithic crystals and the interaction depth of {gamma}-rays. We present in this work an inexpensive modification of the commonly used charge dividing circuits which enables the instantaneous and simultaneous computation of the second order moment of light distribution. This measure provides a good estimate for the depth of interaction and does not affect the determination of the position centroids and the energy release of {gamma}-ray impact. The method has been tested with a detector consisting of a monolithic LSO block sized 42x42x10mm{sup 3} and a position-sensitive photomultiplier tube H8500 from Hamamatsu. The mean spatial resolution of the detector was found to be 3.4mm for the position centroids and 4.9mm for the DOI. The best spatial resolutions were observed at the center of the detector and yielded 1.4mm for the position centroids and 1.9mm for the DOI.

Depth of interaction detection for γ-ray imaging

International Nuclear Information System (INIS)

Lerche, Ch.W.; Doering, M.; Ros, A.; Herrero, V.; Gadea, R.; Aliaga, R.J.; Colom, R.; Mateo, F.; Monzo, J.M.; Ferrando, N.; Toledo, J.F.; Martinez, J.D.; Sebastia, A.; Sanchez, F.; Benlloch, J.M.

2009-01-01

A novel design for an inexpensive depth of interaction capable detector for γ-ray imaging has been developed. The design takes advantage of the strong correlation between the width of the scintillation light distribution in monolithic crystals and the interaction depth of γ-rays. We present in this work an inexpensive modification of the commonly used charge dividing circuits which enables the instantaneous and simultaneous computation of the second order moment of light distribution. This measure provides a good estimate for the depth of interaction and does not affect the determination of the position centroids and the energy release of γ-ray impact. The method has been tested with a detector consisting of a monolithic LSO block sized 42x42x10mm 3 and a position-sensitive photomultiplier tube H8500 from Hamamatsu. The mean spatial resolution of the detector was found to be 3.4mm for the position centroids and 4.9mm for the DOI. The best spatial resolutions were observed at the center of the detector and yielded 1.4mm for the position centroids and 1.9mm for the DOI.

Distinct Reward Properties are Encoded via Corticostriatal Interactions.

Science.gov (United States)

Smith, David V; Rigney, Anastasia E; Delgado, Mauricio R

2016-02-02

The striatum serves as a critical brain region for reward processing. Yet, understanding the link between striatum and reward presents a challenge because rewards are composed of multiple properties. Notably, affective properties modulate emotion while informative properties help obtain future rewards. We approached this problem by emphasizing affective and informative reward properties within two independent guessing games. We found that both reward properties evoked activation within the nucleus accumbens, a subregion of the striatum. Striatal responses to informative, but not affective, reward properties predicted subsequent utilization of information for obtaining monetary reward. We hypothesized that activation of the striatum may be necessary but not sufficient to encode distinct reward properties. To investigate this possibility, we examined whether affective and informative reward properties were differentially encoded in corticostriatal interactions. Strikingly, we found that the striatum exhibited dissociable connectivity patterns with the ventrolateral prefrontal cortex, with increasing connectivity for affective reward properties and decreasing connectivity for informative reward properties. Our results demonstrate that affective and informative reward properties are encoded via corticostriatal interactions. These findings highlight how corticostriatal systems contribute to reward processing, potentially advancing models linking striatal activation to behavior.

Depth of Field Effects for Interactive Direct Volume Rendering

KAUST Repository

Schott, Mathias; Pascal Grosset, A.V.; Martin, Tobias; Pegoraro, Vincent; Smith, Sean T.; Hansen, Charles D.

2011-01-01

In this paper, a method for interactive direct volume rendering is proposed for computing depth of field effects, which previously were shown to aid observers in depth and size perception of synthetically generated images. The presented technique extends those benefits to volume rendering visualizations of 3D scalar fields from CT/MRI scanners or numerical simulations. It is based on incremental filtering and as such does not depend on any precomputation, thus allowing interactive explorations of volumetric data sets via on-the-fly editing of the shading model parameters or (multi-dimensional) transfer functions. © 2011 The Author(s).

Depth of Field Effects for Interactive Direct Volume Rendering

KAUST Repository

Schott, Mathias

2011-06-01

In this paper, a method for interactive direct volume rendering is proposed for computing depth of field effects, which previously were shown to aid observers in depth and size perception of synthetically generated images. The presented technique extends those benefits to volume rendering visualizations of 3D scalar fields from CT/MRI scanners or numerical simulations. It is based on incremental filtering and as such does not depend on any precomputation, thus allowing interactive explorations of volumetric data sets via on-the-fly editing of the shading model parameters or (multi-dimensional) transfer functions. © 2011 The Author(s).

Effects of reflector and crystal surface on the performance of a depth-encoding PET detector with dual-ended readout

International Nuclear Information System (INIS)

Ren, Silin; Yang, Yongfeng; Cherry, Simon R.

2014-01-01

Purpose: Depth encoding detectors are required to improve the spatial resolution and spatial resolution uniformity of small animal positron emission tomography (PET) scanners, as well as dedicated breast and brain scanners. Depth of interaction (DOI) can be measured by using dual-ended readout of lutetium oxyorthosilicate (LSO) scintillator arrays with position-sensitive avalanche photodiodes. Inter-crystal reflectors and crystal surface treatments play important roles in determining the performance of dual-ended detectors. In this paper, the authors evaluated five LSO arrays made with three different intercrystal reflectors and with either polished or unpolished crystal surfaces. Methods: The crystal size in all arrays was 1.5 mm, which is typical of the detector size used in small animal and dedicated breast scanners. The LSO arrays were measured with dual-ended readout and were compared in terms of flood histogram, energy resolution, and DOI resolution performance. Results: The four arrays using enhanced specular reflector (ESR) and Toray reflector provided similar quality flood histograms and the array using Crystal Wrap reflector gave the worst flood histogram. The two arrays using ESR reflector provided the best energy resolution and the array using Crystal Wrap reflector yielded the worst energy resolution. All arrays except the polished ESR array provided good DOI resolution ranging from 1.9 mm to 2.9 mm. DOI resolution improved as the gradient in light collection efficiency with depth (GLCED) increased. The geometric mean energies were also calculated for these dual-ended readout detectors as an alternative to the conventional summed total energy. It was shown that the geometric mean energy is advantageous in that it provides more uniform photopeak amplitude at different depths for arrays with high GLCED, and is beneficial in event selection by allowing a fixed energy window independent of depth. A new method of DOI calculation that improved the linearity

Experimental study of a depth-encoding PET detector inserting horizontal-striped glass between crystal layers

Science.gov (United States)

Yang, J.; Kim, K. B.; Choi, Y.; Kang, J.

2018-04-01

A depth-encoding positron emission tomography (PET) detector inserting a horizontal-striped glass between pixilated scintillation crystal layers was developed and experimentally evaluated. The detector consists of 2-layers of 4×4 LYSO array arranged with a 3.37 mm pitch. Horizontal-striped glasses with 1×4 array with different thickness of 3, 4 and 5 mm were inserted between top- and bottom-crystal layers. Bottom surface of bottom-layer was optically coupled to a 4×4 GAPD array. Sixteen output signals from DOI-PET detector were multiplexed by modified resistive charge division (RCD) networks and multiplexed signals were fed into custom-made charge-sensitive preamplifiers. The four amplified signals were digitized and recorded by the custom-made DAQ system based on FPGA. The four digitized outputs were post-processed and converted to flood histograms for each interaction event. Experimental results revealed that all crystal pixels were clearly identified on the 2D flood histogram without overlapping. Patterns of the 2D flood histogram were constituted with arrangements of [bottom–top–bottom–top–\\ldots–top–bottom–top–bottom] crystal responses in X-direction. These could be achieved by employing horizontal-striped glass that controlled the extent of light dispersion towards the X-direction in crystal layers for generation of a different position mapping for each layer and the modified RCD network that controls degree of charge sharing in readout electronics for reduction of identification error. This study demonstrated the proposed DOI-PET detector can extract the 3D γ-ray interaction position without considerable performance degradation of PET detector from the 2D flood histogram.

Performance of a high-resolution depth-encoding PET detector module using linearly-graded SiPM arrays

Science.gov (United States)

Du, Junwei; Bai, Xiaowei; Gola, Alberto; Acerbi, Fabio; Ferri, Alessandro; Piemonte, Claudio; Yang, Yongfeng; Cherry, Simon R.

2018-02-01

The goal of this study was to exploit the excellent spatial resolution characteristics of a position-sensitive silicon photomultiplier (SiPM) and develop a high-resolution depth-of-interaction (DOI) encoding positron emission tomography (PET) detector module. The detector consists of a 30  ×  30 array of 0.445  ×  0.445  ×  20 mm3 polished LYSO crystals coupled to two 15.5  ×  15.5 mm2 linearly-graded SiPM (LG-SiPM) arrays at both ends. The flood histograms show that all the crystals in the LYSO array can be resolved. The energy resolution, the coincidence timing resolution and the DOI resolution were 21.8  ±  5.8%, 1.23  ±  0.10 ns and 3.8  ±  1.2 mm, respectively, at a temperature of -10 °C and a bias voltage of 35.0 V. The performance did not degrade significantly for event rates of up to 130 000 counts s-1. This detector represents an attractive option for small-bore PET scanner designs that simultaneously emphasize high spatial resolution and high detection efficiency, important, for example, in preclinical imaging of the rodent brain with neuroreceptor ligands.

Depth of interaction resolution measurements for a high resolution PET detector using position sensitive avalanche photodiodes

International Nuclear Information System (INIS)

Yang Yongfeng; Dokhale, Purushottam A; Silverman, Robert W; Shah, Kanai S; McClish, Mickel A; Farrell, Richard; Entine, Gerald; Cherry, Simon R

2006-01-01

We explore dual-ended read out of LSO arrays with two position sensitive avalanche photodiodes (PSAPDs) as a high resolution, high efficiency depth-encoding detector for PET applications. Flood histograms, energy resolution and depth of interaction (DOI) resolution were measured for unpolished LSO arrays with individual crystal sizes of 1.0, 1.3 and 1.5 mm, and for a polished LSO array with 1.3 mm pixels. The thickness of the crystal arrays was 20 mm. Good flood histograms were obtained for all four arrays, and crystals in all four arrays can be clearly resolved. Although the amplitude of each PSAPD signal decreases as the interaction depth moves further from the PSAPD, the sum of the two PSAPD signals is essentially constant with irradiation depth for all four arrays. The energy resolutions were similar for all four arrays, ranging from 14.7% to 15.4%. A DOI resolution of 3-4 mm (including the width of the irradiation band which is ∼2 mm) was obtained for all the unpolished arrays. The best DOI resolution was achieved with the unpolished 1 mm array (average 3.5 mm). The DOI resolution for the 1.3 mm and 1.5 mm unpolished arrays was 3.7 and 4.0 mm respectively. For the polished array, the DOI resolution was only 16.5 mm. Summing the DOI profiles across all crystals for the 1 mm array only degraded the DOI resolution from 3.5 mm to 3.9 mm, indicating that it may not be necessary to calibrate the DOI response separately for each crystal within an array. The DOI response of individual crystals in the array confirms this finding. These results provide a detailed characterization of the DOI response of these PSAPD-based PET detectors which will be important in the design and calibration of a PET scanner making use of this detector approach

Investigation of depth-of-interaction by pulse shape discrimination in multicrystal detectors read out by avalanche photodiodes

International Nuclear Information System (INIS)

Saoudi, A.; Pepin, C.M.; Dion, F.; Bentourkia, M.; Lecomte, R.; Dautet, H.

1999-01-01

The measurement of depth of interaction (DOI) within detectors is necessary to improve resolution uniformity across the FOV of small diameter PET scanners. DOI encoding by pulse shape discrimination (PSD) has definite advantages as it requires only one readout per pixel and it allows DOI measurement of photoelectric and Compton events. The PSD time characteristics of various scintillators were studied with avalanche photodiodes (APD) and the identification capability was tested in multi-crystal assemblies with up to four scintillators. In the PSD time spectrum of an APD-GSO/LSO/BGO/CsI(Tl) assembly, four distinct time peaks at 45, 26, 88 and 150 ns relative to a fast test pulse, having resolution of 10.6, 5.2, 20 and 27 ns, can be easily separated. Whereas the number and position of scintillators in the multi-crystal assemblies affect detector performance, the ability to identify crystals is not compromised. Compton events have a significant effect on PSD accuracy, suggesting that photopeak energy gating should be used for better crystal identification. However, more sophisticated PSD techniques using parametric time-energy histograms can also improve crystal identification in cases where PSD time or energy discrimination alone is inadequate. These results confirm the feasibility of PSD DOI encoding with APD-based detectors for PET

Encoding Theory of Mind in Character Design for Pedagogical Interactive Narrative

Directory of Open Access Journals (Sweden)

Mei Si

2014-01-01

Full Text Available Computer aided interactive narrative allows people to participate actively in a dynamically unfolding story, by playing a character or by exerting directorial control. Because of its potential for providing interesting stories as well as allowing user interaction, interactive narrative has been recognized as a promising tool for providing both education and entertainment. This paper discusses the challenges in creating interactive narratives for pedagogical applications and how the challenges can be addressed by using agent-based technologies. We argue that a rich model of characters and in particular a Theory of Mind capacity are needed. The character architect in the Thespian framework for interactive narrative is presented as an example of how decision-theoretic agents can be used for encoding Theory of Mind and for creating pedagogical interactive narratives.

Collaborative Encoding and Memory Accuracy: Examining the Effects of Interactive Components of Co-Construction Processes

Science.gov (United States)

Foley, Mary Ann; Fried, Adina Rachel; Cowan, Emily; Bays, Rebecca Brooke

2014-01-01

In 2 experiments, the effect of collaborative encoding on memory was examined by testing 2 interactive components of co-construction processes. One component focused on the nature of the interactive exchange between collaborators: As the partners worked together to create descriptions about ways to interact with familiar objects, constraints were…

Development of high-resolution detector module with depth of interaction identification for positron emission tomography

International Nuclear Information System (INIS)

Niknejad, Tahereh; Pizzichemi, Marco; Stringhini, Gianluca; Auffray, Etiennette; Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino; Ferramacho, Luis; Lecoq, Paul; Leong, Carlos; Paganoni, Marco; Rolo, Manuel; Silva, Rui; Silveira, Miguel; Tavernier, Stefaan; Varela, Joao; Zorraquino, Carlos

2017-01-01

We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm"3 matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

Development of high-resolution detector module with depth of interaction identification for positron emission tomography

Energy Technology Data Exchange (ETDEWEB)

Niknejad, Tahereh, E-mail: tniknejad@lip.pt [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Pizzichemi, Marco [University of Milano-Bicocca (Italy); Stringhini, Gianluca [University of Milano-Bicocca (Italy); CERN, Geneve (Switzerland); Auffray, Etiennette [CERN, Geneve (Switzerland); Bugalho, Ricardo; Da Silva, Jose Carlos; Di Francesco, Agostino [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Ferramacho, Luis [PETsys Electronics, Oeiras (Portugal); Lecoq, Paul [CERN, Geneve (Switzerland); Leong, Carlos [PETsys Electronics, Oeiras (Portugal); Paganoni, Marco [University of Milano-Bicocca (Italy); Rolo, Manuel [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); INFN, Turin (Italy); Silva, Rui [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); Silveira, Miguel [PETsys Electronics, Oeiras (Portugal); Tavernier, Stefaan [PETsys Electronics, Oeiras (Portugal); Vrije Universiteit Brussel (Belgium); Varela, Joao [Laboratory of Instrumentation and Experimental Particles Physics, Lisbon (Portugal); CERN, Geneve (Switzerland); Zorraquino, Carlos [Biomedical Image Technologies Lab, Universidad Politécnica de Madrid (Spain); CIBER-BBN, Universidad Politécnica de Madrid (Spain)

2017-02-11

We have developed a Time-of-flight high resolution and commercially viable detector module for the application in small PET scanners. A new approach to depth of interaction (DOI) encoding with low complexity for a pixelated crystal array using a single side readout and 4-to-1 coupling between scintillators and photodetectors was investigated. In this method the DOI information is estimated using the light sharing technique. The detector module is a 1.53×1.53×15 mm{sup 3} matrix of 8×8 LYSO scintillator with lateral surfaces optically depolished separated by reflective foils. The crystal array is optically coupled to 4×4 silicon photomultipliers (SiPM) array and readout by a high performance front-end ASIC with TDC capability (50 ps time binning). The results show an excellent crystal identification for all the scintillators in the matrix, a timing resolution of 530 ps, an average DOI resolution of 5.17 mm FWHM and an average energy resolution of 18.29% FWHM. - Highlights: • A new method for DOI encoding for PET detectors based on light sharing is proposed. • A prototype module with LYSO scintillator matrix coupled to SiPMs array is produced. • The module has one side readout and 4-to-1 coupling between scintillators and SiPMs. • A compact TOF front-end ASIC is used. • Excellent performances are shown by the prototype module.

Depth-of-interaction measurement in a single-layer crystal array with a single-ended readout using digital silicon photomultiplier

International Nuclear Information System (INIS)

Lee, Min Sun; Lee, Jae Sung

2015-01-01

We present the first experimental evaluation of a depth-of-interaction (DOI) positron emission tomography (PET) detector using a digital silicon photomultiplier (dSiPM). To measure DOI information from a mono-layer array of scintillation crystals with a single-ended readout, our group has previously proposed and developed a new method based on light spread using triangular reflectors. Since this method relies on measurement of the light distribution, dSiPM, which has a fully digital interface, has several merits for our DOI measurement. The DOI PET detector comprised of a dSiPM sensor (DPC-3200-22-44) coupled with a 14   ×   14 array of 2 mm  ×  2 mm  ×  20 mm unpolished LGSO crystals. All crystals were covered with triangular reflectors. To obtain a good performance of the DOI PET detector, several parameters of detector were selected as a preliminary experiment. Detector performance was evaluated with the selected parameters and the optimal experimental setup, and a DOI measurement was conducted by irradiating the crystal block at five DOI positions spaced at intervals of 4 mm. Maximum-likelihood estimation was employed for DOI positioning and the optimal DOI estimation scheme was also investigated in this study. As a result, the DOI PET detector showed clear crystal identification. The energy resolution (full-width at half-maximum (FWHM)) averaged over all depths was 10.21%  ±  0.15% at 511 keV, and time resolution averaged over all depths was 1198.61   ±   39.70 ps FWHM. The average DOI positioning accuracy for all depths was 74.22%  ±  6.77%, which equates to DOI resolution of 4.67 mm. Energy and DOI resolutions were uniform over all crystal positions except for the back parts of the array. Furthermore, additional simulation studies were conducted to verify the results of our DOI measurement method that is combined with dSiPM technology. In conclusion, our continuous DOI PET detector

Continuous Non-malleable Codes

DEFF Research Database (Denmark)

Faust, Sebastian; Mukherjee, Pratyay; Nielsen, Jesper Buus

2014-01-01

or modify it to the encoding of a completely unrelated value. This paper introduces an extension of the standard non-malleability security notion - so-called continuous non-malleability - where we allow the adversary to tamper continuously with an encoding. This is in contrast to the standard notion of non...... is necessary to achieve continuous non-malleability in the split-state model. Moreover, we illustrate that none of the existing constructions satisfies our uniqueness property and hence is not secure in the continuous setting. We construct a split-state code satisfying continuous non-malleability. Our scheme...... is based on the inner product function, collision-resistant hashing and non-interactive zero-knowledge proofs of knowledge and requires an untamperable common reference string. We apply continuous non-malleable codes to protect arbitrary cryptographic primitives against tampering attacks. Previous...

Effect of interaction between seed size and sowing depth of cashew ...

African Journals Online (AJOL)

Effect of interaction between seed size and sowing depth of cashew Anacardium occidentale (L) on seedlings emergence and height under treatment with organic and inorganic fertilizer in Gidan-Waya, Southern Guinea Savanna, Nigeria.

The proximate memory mechanism underlying the survival-processing effect: richness of encoding or interactive imagery?

Science.gov (United States)

Kroneisen, Meike; Erdfelder, Edgar; Buchner, Axel

2013-01-01

Nairne and collaborators showed that assessing the relevance of words in the context of an imagined survival scenario boosts memory for these words. Although this survival-processing advantage has attracted a considerable amount of research, little is known about the proximate memory mechanism mediating this effect. Recently, Kroneisen and Erdfelder (2011) argued that it is not survival processing itself that facilitates recall but rather the richness and distinctiveness of encoding that is triggered by the survival-processing task. Alternatively, however, it is also conceivable that survival processing fosters interactive imagery, a process known to improve associative learning. To test these explanations we compared relevance-rating and interactive imagery tasks for survival and control scenarios. Results show that the survival advantage replicates in the relevance-rating condition but vanishes in the interactive imagery condition. This refutes the interactive imagery explanation and corroborates the richness-of-encoding hypothesis of the survival-processing effect.

Front-end circuit for position sensitive silicon and vacuum tube photomultipliers with gain control and depth of interaction measurement

International Nuclear Information System (INIS)

Herrero, Vicente; Colom, Ricardo; Gadea, Rafael; Lerche, Christoph W.; Cerda, Joaquin; Sebastia, Angel; Benlloch, Jose M.

2007-01-01

Silicon Photomultipliers, though still under development for mass production, may be an alternative to traditional Vacuum Photomultipliers Tubes (VPMT). As a consequence, electronic front-ends initially designed for VPMT will need to be modified. In this simulation, an improved architecture is presented which is able to obtain impact position and depth of interaction of a gamma ray within a continuous scintillation crystal, using either kind of PM. A current sensitive preamplifier stage with individual gain adjustment interfaces the multi-anode PM outputs with a current division resistor network. The preamplifier stage allows to improve front-end processing delay and temporal resolution behavior as well as to increase impact position calculation resolution. Depth of interaction (DOI) is calculated from the width of the scintillation light distribution, which is related to the sum of voltages in resistor network input nodes. This operation is done by means of a high-speed current mode scheme

Continuous limit of discrete systems with long-range interaction

International Nuclear Information System (INIS)

Tarasov, Vasily E

2006-01-01

Discrete systems with long-range interactions are considered. Continuous medium models as continuous limit of discrete chain system are defined. Long-range interactions of chain elements that give the fractional equations for the medium model are discussed. The chain equations of motion with long-range interaction are mapped into the continuum equation with the Riesz fractional derivative. We formulate the consistent definition of continuous limit for the systems with long-range interactions. In this paper, we consider a wide class of long-range interactions that give fractional medium equations in the continuous limit. The power-law interaction is a special case of this class

Multiview Depth-Image Compression Using an Extended H.264 Encoder

NARCIS (Netherlands)

Morvan, Y.; Farin, D.S.; With, de P.H.N.; Blanc-Talon, J.; Philips, W.

2007-01-01

This paper presents a predictive-coding algorithm for the compression of multiple depth-sequences obtained from a multi-camera acquisition setup. The proposed depth-prediction algorithm works by synthesizing a virtual depth-image that matches the depth-image (of the predicted camera). To generate

Atom depth analysis delineates mechanisms of protein intermolecular interactions

International Nuclear Information System (INIS)

Alocci, Davide; Bernini, Andrea; Niccolai, Neri

2013-01-01

Highlights: •3D atom depth analysis is proposed to identify different layers in protein structures. •Amino acid contents for each layers have been analyzed for a large protein dataset. •Charged amino acids in the most external layer are present at very different extents. •Atom depth indexes of K residues reflect their side chains flexibility. •Mobile surface charges can be responsible for long range protein–protein recognition. -- Abstract: The systematic analysis of amino acid distribution, performed inside a large set of resolved protein structures, sheds light on possible mechanisms driving non random protein–protein approaches. Protein Data Bank entries have been selected using as filters a series of restrictions ensuring that the shape of protein surface is not modified by interactions with large or small ligands. 3D atom depth has been evaluated for all the atoms of the 2,410 selected structures. The amino acid relative population in each of the structural layers formed by grouping atoms on the basis of their calculated depths, has been evaluated. We have identified seven structural layers, the inner ones reproducing the core of proteins and the outer one incorporating their most protruding moieties. Quantitative analysis of amino acid contents of structural layers identified, as expected, different behaviors. Atoms of Q, R, K, N, D residues are increasingly more abundant in going from core to surfaces. An opposite trend is observed for V, I, L, A, C, and G. An intermediate behavior is exhibited by P, S, T, M, W, H, F and Y. The outer structural layer hosts predominantly E and K residues whose charged moieties, protruding from outer regions of the protein surface, reorient free from steric hindrances, determining specific electrodynamics maps. This feature may represent a protein signature for long distance effects, driving the formation of encounter complexes and the eventual short distance approaches that are required for protein�

Naturalistic depth perception and binocular vision

OpenAIRE

Maiello, G.

2017-01-01

Humans continuously move both their eyes to redirect their foveae to objects at new depths. To correctly execute these complex combinations of saccades, vergence eye movements and accommodation changes, the visual system makes use of multiple sources of depth information, including binocular disparity and defocus. Furthermore, during development, both fine-tuning of oculomotor control as well as correct eye growth are likely driven by complex interactions between eye movements, accommodation,...

Evaluation of color encodings for high dynamic range pixels

Science.gov (United States)

Boitard, Ronan; Mantiuk, Rafal K.; Pouli, Tania

2015-03-01

Traditional Low Dynamic Range (LDR) color spaces encode a small fraction of the visible color gamut, which does not encompass the range of colors produced on upcoming High Dynamic Range (HDR) displays. Future imaging systems will require encoding much wider color gamut and luminance range. Such wide color gamut can be represented using floating point HDR pixel values but those are inefficient to encode. They also lack perceptual uniformity of the luminance and color distribution, which is provided (in approximation) by most LDR color spaces. Therefore, there is a need to devise an efficient, perceptually uniform and integer valued representation for high dynamic range pixel values. In this paper we evaluate several methods for encoding colour HDR pixel values, in particular for use in image and video compression. Unlike other studies we test both luminance and color difference encoding in a rigorous 4AFC threshold experiments to determine the minimum bit-depth required. Results show that the Perceptual Quantizer (PQ) encoding provides the best perceptual uniformity in the considered luminance range, however the gain in bit-depth is rather modest. More significant difference can be observed between color difference encoding schemes, from which YDuDv encoding seems to be the most efficient.

Similar patterns of neural activity predict memory function during encoding and retrieval.

Science.gov (United States)

Kragel, James E; Ezzyat, Youssef; Sperling, Michael R; Gorniak, Richard; Worrell, Gregory A; Berry, Brent M; Inman, Cory; Lin, Jui-Jui; Davis, Kathryn A; Das, Sandhitsu R; Stein, Joel M; Jobst, Barbara C; Zaghloul, Kareem A; Sheth, Sameer A; Rizzuto, Daniel S; Kahana, Michael J

2017-07-15

Neural networks that span the medial temporal lobe (MTL), prefrontal cortex, and posterior cortical regions are essential to episodic memory function in humans. Encoding and retrieval are supported by the engagement of both distinct neural pathways across the cortex and common structures within the medial temporal lobes. However, the degree to which memory performance can be determined by neural processing that is common to encoding and retrieval remains to be determined. To identify neural signatures of successful memory function, we administered a delayed free-recall task to 187 neurosurgical patients implanted with subdural or intraparenchymal depth electrodes. We developed multivariate classifiers to identify patterns of spectral power across the brain that independently predicted successful episodic encoding and retrieval. During encoding and retrieval, patterns of increased high frequency activity in prefrontal, MTL, and inferior parietal cortices, accompanied by widespread decreases in low frequency power across the brain predicted successful memory function. Using a cross-decoding approach, we demonstrate the ability to predict memory function across distinct phases of the free-recall task. Furthermore, we demonstrate that classifiers that combine information from both encoding and retrieval states can outperform task-independent models. These findings suggest that the engagement of a core memory network during either encoding or retrieval shapes the ability to remember the past, despite distinct neural interactions that facilitate encoding and retrieval. Copyright © 2017 Elsevier Inc. All rights reserved.

Continuous depth-sensing nano-mechanical characterization of living, fixed and dehydrated cells attached on a glass substrate

Energy Technology Data Exchange (ETDEWEB)

Yang, Yun-Ta; Liao, Jiunn-Der; Chang, Chia-Wei [Department of Materials Science and Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China); Lin, Chou-Ching K [Department of Neurology, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China); Ju, Ming-Shaung, E-mail: jdliao@mail.ncku.edu.tw [Department of Mechanical Engineering, National Cheng Kung University, No. 1, University Road, Tainan 70101, Taiwan (China)

2010-07-16

Continuous depth-sensing nano-indentation on living, fixed and dehydrated fibroblast cells was performed using a dynamic contact module and vertically measured from a pre-contact state to the glass substrate. The nano-indentation tip-on-cell approaches took advantage of finding a contact surface, followed by obtaining a continuous nano-mechanical profile along the nano-indentation depths. In the experiment, serial indentations from the leading edge, i.e., the lamellipodium to nucleus regions of living, fixed and dehydrated fibroblast cells were examined. Nano-indentations on a living cell anchored upon glass substrate were competent in finding the tip-on-cell contact surfaces and cell heights. For the result on the fixed and the dehydrated cells, cellular nano-mechanical properties were clearly characterized by continuous harmonic contact stiffness (HCS) measurements. The relations of HCS versus measured displacement, varied from the initial tip-on-cell contact to the glass substrate, were presumably divided into three stages, respectively induced by cellular intrinsic behavior, the substrate-dominant property, and the substrate property. This manifestation is beneficial to elucidate how the underlying substrate influences the interpretation of the nano-mechanical property of thin soft matter on a hard substrate. These findings, based upon continuous depth-sensing nano-indentations, are presumably valuable as a reference to related work, e.g., accomplished by atomic force microscopy.

Continuous depth-sensing nano-mechanical characterization of living, fixed and dehydrated cells attached on a glass substrate

International Nuclear Information System (INIS)

Yang, Yun-Ta; Liao, Jiunn-Der; Chang, Chia-Wei; Lin, Chou-Ching K; Ju, Ming-Shaung

2010-01-01

Continuous depth-sensing nano-indentation on living, fixed and dehydrated fibroblast cells was performed using a dynamic contact module and vertically measured from a pre-contact state to the glass substrate. The nano-indentation tip-on-cell approaches took advantage of finding a contact surface, followed by obtaining a continuous nano-mechanical profile along the nano-indentation depths. In the experiment, serial indentations from the leading edge, i.e., the lamellipodium to nucleus regions of living, fixed and dehydrated fibroblast cells were examined. Nano-indentations on a living cell anchored upon glass substrate were competent in finding the tip-on-cell contact surfaces and cell heights. For the result on the fixed and the dehydrated cells, cellular nano-mechanical properties were clearly characterized by continuous harmonic contact stiffness (HCS) measurements. The relations of HCS versus measured displacement, varied from the initial tip-on-cell contact to the glass substrate, were presumably divided into three stages, respectively induced by cellular intrinsic behavior, the substrate-dominant property, and the substrate property. This manifestation is beneficial to elucidate how the underlying substrate influences the interpretation of the nano-mechanical property of thin soft matter on a hard substrate. These findings, based upon continuous depth-sensing nano-indentations, are presumably valuable as a reference to related work, e.g., accomplished by atomic force microscopy.

Depth distribution of abiotic drivers of N mineralization and methane emission from a continuously and intermittently flooded Bangladeshi paddy soil

Science.gov (United States)

Akter, Masuda; Kader, Md. Abdul; Pierreux, Sofie; Boeckx, Pascal; Kamal, Ahammad Mostafa; Sleutel, Steven

2016-04-01

Water-saving irrigation such as AWD may significantly alter depth profiles of moisture content, pH, Eh and soil microbial activity. Modelling the effect of irrigation management on soil N mineralization, therefore requires detailed insight into depth distribution of these variables and dissolved organic carbon (DOC), and evolution of electron acceptors. We set up a field experiment at Bangladesh Agricultural University from January to May' 2015. The cultivated rice variety (BRRI dhan28) was grown under continuous flooding (CF) and alternate wetting and drying (AWD) management, with 120 kg N ha-1(N120) or without (N0)N fertilizer application. We measured soil mineral N and plant N uptake to evaluate N mineralization. CH4 emissions were monitored with timely gas sample collection and GC-analysis. Soil Eh at four depths and temperature at two depths were monitored continuously by Eh/T°-probes connected to a HYPNOS III data logger (MVH, The Netherlands). Simultaneously, soil solution from three depths were sampled with rhizon samplers to track DOC, Fe and Mn in solution. Over the growing season soil and air temperature increased by 8°C, and soil pH stayed near neutral (6.7 to 7.8). In all depths of AWD and CF, Eh dropped sharply to methanic conditions within 21 days after transplanting (DAT). Low redox-potential continued until 77DAT in all cases, except in the puddle layers under AWD, where redox raised to -200mV during drainage. Fe and Mn in soil solution increased gradually over the growing season, indicating continued reductive dissolution of Fe and Mn (hydro-)oxides. DOC increased continuously as well in all depths. Besides to release of DOC bound to pedogenic oxides upon their reductive dissolution, higher plant and soil microbial activity with increasing soil temperature (till 28°C) through the growing season explains the increasing DOC levels. Increasing methanogenic activity as indicated by the high CH4 emissions at 70-84DAT under both CF and AWD is

Interactive Development of Community Education and Migrant Workers’ Continuing Education

Institute of Scientific and Technical Information of China (English)

Ning; WANG

2015-01-01

Community education is an essential carrier of continuing education and plays a positive role in promoting continuing education of migrant workers. On the one hand,it can raise employment quality and labor skills of migrant workers; on the other hand,it manifests function of serving society of community education. Besides,it is also an important measure for building learning society and lifelong learning system.From the perspective of interactive development,it discusses interactive relationship between community education and migrant workers’ continuing education,analyzes their interactive mechanism,and comes up with recommendations for developing community education and migrant workers’ continuing education.

Low Complexity HEVC Encoder for Visual Sensor Networks

Directory of Open Access Journals (Sweden)

Zhaoqing Pan

2015-12-01

Full Text Available Visual sensor networks (VSNs can be widely applied in security surveillance, environmental monitoring, smart rooms, etc. However, with the increased number of camera nodes in VSNs, the volume of the visual information data increases significantly, which becomes a challenge for storage, processing and transmitting the visual data. The state-of-the-art video compression standard, high efficiency video coding (HEVC, can effectively compress the raw visual data, while the higher compression rate comes at the cost of heavy computational complexity. Hence, reducing the encoding complexity becomes vital for the HEVC encoder to be used in VSNs. In this paper, we propose a fast coding unit (CU depth decision method to reduce the encoding complexity of the HEVC encoder for VSNs. Firstly, the content property of the CU is analyzed. Then, an early CU depth decision method and a low complexity distortion calculation method are proposed for the CUs with homogenous content. Experimental results show that the proposed method achieves 71.91% on average encoding time savings for the HEVC encoder for VSNs.

Development of a prototype PET scanner with depth-of-interaction measurement using solid-state photomultiplier arrays and parallel readout electronics.

Science.gov (United States)

Shao, Yiping; Sun, Xishan; Lan, Kejian A; Bircher, Chad; Lou, Kai; Deng, Zhi

2014-03-07

In this study, we developed a prototype animal PET by applying several novel technologies to use solid-state photomultiplier (SSPM) arrays to measure the depth of interaction (DOI) and improve imaging performance. Each PET detector has an 8 × 8 array of about 1.9 × 1.9 × 30.0 mm(3) lutetium-yttrium-oxyorthosilicate scintillators, with each end optically connected to an SSPM array (16 channels in a 4 × 4 matrix) through a light guide to enable continuous DOI measurement. Each SSPM has an active area of about 3 × 3 mm(2), and its output is read by a custom-developed application-specific integrated circuit to directly convert analogue signals to digital timing pulses that encode the interaction information. These pulses are transferred to and are decoded by a field-programmable gate array-based time-to-digital convertor for coincident event selection and data acquisition. The independent readout of each SSPM and the parallel signal process can significantly improve the signal-to-noise ratio and enable the use of flexible algorithms for different data processes. The prototype PET consists of two rotating detector panels on a portable gantry with four detectors in each panel to provide 16 mm axial and variable transaxial field-of-view (FOV) sizes. List-mode ordered subset expectation maximization image reconstruction was implemented. The measured mean energy, coincidence timing and DOI resolution for a crystal were about 17.6%, 2.8 ns and 5.6 mm, respectively. The measured transaxial resolutions at the center of the FOV were 2.0 mm and 2.3 mm for images reconstructed with and without DOI, respectively. In addition, the resolutions across the FOV with DOI were substantially better than those without DOI. The quality of PET images of both a hot-rod phantom and mouse acquired with DOI was much higher than that of images obtained without DOI. This study demonstrates that SSPM arrays and advanced readout/processing electronics can be used to develop a practical DOI

Transparency in stereopsis: parallel encoding of overlapping depth planes.

Science.gov (United States)

Reeves, Adam; Lynch, David

2017-08-01

We report that after extensive training, expert adults can accurately report the number, up to six, of transparent overlapping depth planes portrayed by brief (400 ms or 200 ms) random-element stereoscopic displays, and can well discriminate six from seven planes. Naïve subjects did poorly above three planes. Displays contained seven rows of 12 randomly located ×'s or +'s; jittering the disparities and number in each row to remove spurious cues had little effect on accuracy. Removing the central 3° of the 10° display to eliminate foveal vision hardly reduced the number of reportable planes. Experts could report how many of six planes contained +'s when the remainder contained ×'s, and most learned to report up to six planes in reverse contrast (left eye white +'s; right eye black +'s). Long-term training allowed some experts to reach eight depth planes. Results suggest that adult stereoscopic vision can learn to distinguish the outputs of six or more statistically independent, contrast-insensitive, narrowly tuned, asymmetric disparity channels in parallel.

Layered compression for high-precision depth data.

Science.gov (United States)

Miao, Dan; Fu, Jingjing; Lu, Yan; Li, Shipeng; Chen, Chang Wen

2015-12-01

With the development of depth data acquisition technologies, access to high-precision depth with more than 8-b depths has become much easier and determining how to efficiently represent and compress high-precision depth is essential for practical depth storage and transmission systems. In this paper, we propose a layered high-precision depth compression framework based on an 8-b image/video encoder to achieve efficient compression with low complexity. Within this framework, considering the characteristics of the high-precision depth, a depth map is partitioned into two layers: 1) the most significant bits (MSBs) layer and 2) the least significant bits (LSBs) layer. The MSBs layer provides rough depth value distribution, while the LSBs layer records the details of the depth value variation. For the MSBs layer, an error-controllable pixel domain encoding scheme is proposed to exploit the data correlation of the general depth information with sharp edges and to guarantee the data format of LSBs layer is 8 b after taking the quantization error from MSBs layer. For the LSBs layer, standard 8-b image/video codec is leveraged to perform the compression. The experimental results demonstrate that the proposed coding scheme can achieve real-time depth compression with satisfactory reconstruction quality. Moreover, the compressed depth data generated from this scheme can achieve better performance in view synthesis and gesture recognition applications compared with the conventional coding schemes because of the error control algorithm.

GEOMORPHIC AND HYDROLOGIC INTERACTIONS IN THE DETERMINATION OF EQUILIBRIUM SOIL DEPTH

Science.gov (United States)

Nicotina, L.; Rinaldo, A.; Tarboton, D. G.

2009-12-01

In this work we propose numerical studies of the interactions between hydrology and geomorphology in the formation of the actual soil depth that drives ecologic and hydrologic processes. Sediment transport and geomorphic landscape evolution processes (i.e. erosion/deposition vs. soil production) strongly influence hydrology, carbon sequestration, soil formation and stream water chemistry. The process of rock conversion into soil originates a strong hydrologic control through the formation of the soil depth that participates to hydrologic processes, influence vegetation type and patterns and actively participate in the co-evolution mechanisms that shape the landscape. The description of spatial patterns in hydrology is usually constrained by the availability of field data, especially when dealing with quantities that are not easily measurable. In these circumstances it is deemed fundamental the capability of deriving hydrologic boundary conditions from physically based approaches. Here we aim, in a general framework, at the formulation of an integrated approach for the prediction of soil depth by mean of i) soil production models and ii) geomorphic transport laws. The processes that take place in the critical zone are driven by the extension of it and have foundamental importance over short time scales as well as on geologic time scales (i.e. as biota affects climate that drives hydrology and thus contributes on shaping the landscape). Our study aims at the investigation of the relationships between soil depth, topography and runoff production, we also address the mechanisms that bring to the development of actual patterns of soil depths which at the same time influence runoff. We use a schematic representation of the hydrologic processes that relies on the description of the topography (throuh a topographic wetness index) and the spatially variable soil depths. Such a model is applied in order to investigate the development of equilibrium soil depth patterns under

Interaction-aided continuous time quantum search

International Nuclear Information System (INIS)

Bae, Joonwoo; Kwon, Younghun; Baek, Inchan; Yoon, Dalsun

2005-01-01

The continuous quantum search algorithm (based on the Farhi-Gutmann Hamiltonian evolution) is known to be analogous to the Grover (or discrete time quantum) algorithm. Any errors introduced in Grover algorithm are fatal to its success. In the same way the Farhi-Gutmann Hamiltonian algorithm has a severe difficulty when the Hamiltonian is perturbed. In this letter we will show that the interaction term in quantum search Hamiltonian (actually which is in the generalized quantum search Hamiltonian) can save the perturbed Farhi-Gutmann Hamiltonian that should otherwise fail. We note that this fact is quite remarkable since it implies that introduction of interaction can be a way to correct some errors on the continuous time quantum search

Comparison between different encoding schemes for synthetic aperture imaging

DEFF Research Database (Denmark)

Nikolov, Svetoslav; Jensen, Jørgen Arendt

2002-01-01

and spatio-temporal encoding was investigated. Experiments on wire phantom in water were carried out to quantify the gain from the different encodings. The gain in SNR using an FM modulated pulse is 12 dB. The penetration depth of the images was studied using tissue mimicking phantom with frequency dependent......Synthetic transmit aperture ultrasound (STAU) imaging can create images with as low as 2 emissions, making it attractive for 3D real-time imaging. Two are the major problems to be solved: (1) complexity of the hardware involved, and (2) poor image quality due to low signal to noise ratio (SNR). We...... attenuation of 0.5 dB/(cm MHz). The combination of spatial and temporal encoding have highest penetration depth. Images to a depth of 110 mm, can successfully be made with contrast resolution comparable to that of a linear array image. The in-vivo scans show that the motion artifacts do not significantly...

Multifunctionality is affected by interactions between green roof plant species, substrate depth, and substrate type.

Science.gov (United States)

Dusza, Yann; Barot, Sébastien; Kraepiel, Yvan; Lata, Jean-Christophe; Abbadie, Luc; Raynaud, Xavier

2017-04-01

Green roofs provide ecosystem services through evapotranspiration and nutrient cycling that depend, among others, on plant species, substrate type, and substrate depth. However, no study has assessed thoroughly how interactions between these factors alter ecosystem functions and multifunctionality of green roofs. We simulated some green roof conditions in a pot experiment. We planted 20 plant species from 10 genera and five families (Asteraceae, Caryophyllaceae, Crassulaceae, Fabaceae, and Poaceae) on two substrate types (natural vs. artificial) and two substrate depths (10 cm vs. 30 cm). As indicators of major ecosystem functions, we measured aboveground and belowground biomasses, foliar nitrogen and carbon content, foliar transpiration, substrate water retention, and dissolved organic carbon and nitrates in leachates. Interactions between substrate type and depth strongly affected ecosystem functions. Biomass production was increased in the artificial substrate and deeper substrates, as was water retention in most cases. In contrast, dissolved organic carbon leaching was higher in the artificial substrates. Except for the Fabaceae species, nitrate leaching was reduced in deep, natural soils. The highest transpiration rates were associated with natural soils. All functions were modulated by plant families or species. Plant effects differed according to the observed function and the type and depth of the substrate. Fabaceae species grown on natural soils had the most noticeable patterns, allowing high biomass production and high water retention but also high nitrate leaching from deep pots. No single combination of factors enhanced simultaneously all studied ecosystem functions, highlighting that soil-plant interactions induce trade-offs between ecosystem functions. Substrate type and depth interactions are major drivers for green roof multifunctionality.

S3D depth-axis interaction for video games: performance and engagement

Science.gov (United States)

Zerebecki, Chris; Stanfield, Brodie; Hogue, Andrew; Kapralos, Bill; Collins, Karen

2013-03-01

Game developers have yet to embrace and explore the interactive stereoscopic 3D medium. They typically view stereoscopy as a separate mode that can be disabled throughout the design process and rarely develop game mechanics that take advantage of the stereoscopic 3D medium. What if we designed games to be S3D-specific and viewed traditional 2D viewing as a separate mode that can be disabled? The design choices made throughout such a process may yield interesting and compelling results. Furthermore, we believe that interaction within a stereoscopic 3D environment is more important than the visual experience itself and therefore, further exploration is needed to take into account the interactive affordances presented by stereoscopic 3D displays. Stereoscopic 3D displays allow players to perceive objects at different depths, thus we hypothesize that designing a core mechanic to take advantage of this viewing paradigm will create compelling content. In this paper, we describe Z-Fighter a game that we have developed that requires the player to interact directly along the stereoscopic 3D depth axis. We also outline an experiment conducted to investigate the performance, perception, and enjoyment of this game in stereoscopic 3D vs. traditional 2D viewing.

Performance of a DOI-encoding small animal PET system with monolithic scintillators

International Nuclear Information System (INIS)

Carles, M.; Lerche, Ch.W.; Sánchez, F.; Orero, A.; Moliner, L.; Soriano, A.; Benlloch, J.M.

2012-01-01

PET systems designed for specific applications require high resolution and sensitivity instrumentation. In dedicated system design smaller ring diameters and deeper crystals are widely used in order to increase the system sensitivity. However, this design increases the parallax error, which degrades the spatial image resolution gradually from the center to the edge of the field-of-view (FOV). Our group has designed a depth of interaction(DOI)-encoding small animal PET system based on monolithic crystals. In this work we investigate the restoration of radial resolution for transaxially off-center sources using the DOI information provided by our system. For this purpose we have designed a support for point like sources adapted to our system geometry that allows a spatial compression and resolution response study. For different point source radial positions along vertical and horizontal axes of a FOV transaxial plane we compare the results obtained by three methods: without DOI information, with the DOI provided by our system and with the assumption that all the γ-rays interact at half depth of the crystal thickness. Results show an improvement of the mean resolution of 10% with the half thickness assumption and a 16% achieved using the DOI provided by the system. Furthermore, a 10% restoration of the resolution uniformity is obtained using the half depth assumption and an 18% restoration using measured DOI.

A LSO scintillator array for a PET detector module with depth of interaction measurement

International Nuclear Information System (INIS)

Huber, J.S.; Moses, W.W.; Andreaco, M.S.; Petterson, O.

2000-01-01

We present construction methods and performance results for a production scintillator array of 64 optically isolated, 3 mm x 3 mm x 30 mm sized LSO crystals. This scintillator array has been developed for a PET detector module consisting of the 8x8 LSO array coupled on one end to a single photomultiplier tube (PMT) and on the opposite end to a 64 pixel array of silicon photodiodes (PD). The PMT provides an accurate timing pulse and initial energy discrimination, the PD identifies the crystal of interaction, the sum provides a total energy signal, and the PD/(PD+PMT) ratio determines the depth of interaction (DOI). Unlike the previous LSO array prototypes, we now glue Lumirror reflector material directly onto 4 sides of each crystal to obtain an easily manufactured, mechanically rugged array with our desired depth dependence. With 511 keV excitation, we obtain a total energy signal of 3600 electrons, pulse-height resolution of 25% fwhm, and 6-15 mm fwhm DOI resolution

Interaction of discrete and continuous boundary layer modes to cause transition

International Nuclear Information System (INIS)

Durbin, Paul A.; Zaki, Tamer A.; Liu Yang

2009-01-01

The interaction of discrete and continuous Orr-Sommerfeld modes in a boundary layer is studied by computer simulation. The discrete mode is an unstable Tollmien-Schlichting wave. The continuous modes generate jet-like disturbances inside the boundary layer. Either mode alone does not cause transition to turbulence; however, the interaction between them does. The continuous mode jets distort the discrete modes, producing Λ shaped vortices. Breakdown to turbulence is subsequent. The lateral spacing of the Λ's is sometimes the same as the wavelength of the continuous mode, sometimes it differs, depending on the ratio of wavelength to boundary layer thickness.

A machine learning method for fast and accurate characterization of depth-of-interaction gamma cameras

DEFF Research Database (Denmark)

Pedemonte, Stefano; Pierce, Larry; Van Leemput, Koen

2017-01-01

to impose the depth-of-interaction in an experimental set-up. In this article we introduce a machine learning approach for extracting accurate forward models of gamma imaging devices from simple pencil-beam measurements, using a nonlinear dimensionality reduction technique in combination with a finite...

Improving continuing medical education by enhancing interactivity: lessons from Iran.

Science.gov (United States)

Faghihi, Seyed Aliakbar; Khankeh, Hamid Reza; Hosseini, Seyed Jalil; Soltani Arabshahi, Seyed Kamran; Faghih, Zahra; Parikh, Sagar V; Shirazi, Mandana

2016-04-01

Continuing Medical Education (CME) has been considered as a lifelong commitment for doctors to provide the optimal care for patients. Despite a long history of creating CME programs, outcomes are far from ideal. The present qualitative study aims to clarify the barriers affecting effectiveness of the CME programs in Iran based on the experiences of general practitioners. Sixteen general practitioners were recruited to participate in in-depth interviews and field observations concerning experiences with CME. The study was performed using a qualitative content analysis method. The codes, categories and themes were explored through an inductive process in which the researchers moved from specific to general. The participants' experiences identified a number of barriers, particularly insufficient interaction with the instructors; additional problems included the teachers' use of an undifferentiated approach; unreal and abstract CME; and ignorance of the diverse reasons to participate in CME. Based on the study results, there are multiple barriers to effective implementation of CME in Iran. The key barriers include insufficient interaction between the trainees and providers, which must be considered by other stakeholders and program designers. Such interactions would facilitate improved program design, invite more specific tailoring of the education to the participants, allow for more effective educational methods and set the stage for outcome evaluation from the learners actually applying their new knowledge in practice. Replication of these findings with another sample would improve confidence in these recommendations, but these findings are broadly consistent with findings in the educational literature on improving the efficacy of CME.

Depth of word processing in Alzheimer patients and normal controls: a magnetoencephalographic (MEG) study.

Science.gov (United States)

Walla, P; Püregger, E; Lehrner, J; Mayer, D; Deecke, L; Dal Bianco, P

2005-05-01

Effects related to depth of verbal information processing were investigated in probable Alzheimer's disease patients (AD) and age matched controls. During word encoding sessions 10 patients and 10 controls had either to decide whether the letter "s" appeared in visually presented words (alphabetical decision, shallow encoding), or whether the meaning of each presented word was animate or inanimate (lexical decision, deep encoding). These encoding sessions were followed by test sessions during which all previously encoded words were presented again together with the same number of new words. The task was then to discriminate between repeated and new words. Magnetic field changes related to brain activity were recorded with a whole cortex MEG.5 probable AD patients showed recognition performances above chance level related to both depths of information processing. Those patients and 5 age matched controls were then further analysed. Recognition performance was poorer in probable AD patients compared to controls for both levels of processing. However, in both groups deep encoding led to a higher recognition performance than shallow encoding. We therefore conclude that the performance reduction in the patient group was independent of depth of processing. Reaction times related to false alarms differed between patients and controls after deep encoding which perhaps could already be used for supporting an early diagnosis. The analysis of the physiological data revealed significant differences between correctly recognised repetitions and correctly classified new words (old/new-effect) in the control group which were missing in the patient group after deep encoding. The lack of such an effect in the patient group is interpreted as being due to the respective neuropathology related to probable AD. The present results demonstrate that magnetic field recordings represent a useful tool to physiologically distinguish between probable AD and age matched controls.

Exploring Interacting Quantum Many-Body Systems by Experimentally Creating Continuous Matrix Product States in Superconducting Circuits

Directory of Open Access Journals (Sweden)

C. Eichler

2015-12-01

Full Text Available Improving the understanding of strongly correlated quantum many-body systems such as gases of interacting atoms or electrons is one of the most important challenges in modern condensed matter physics, materials research, and chemistry. Enormous progress has been made in the past decades in developing both classical and quantum approaches to calculate, simulate, and experimentally probe the properties of such systems. In this work, we use a combination of classical and quantum methods to experimentally explore the properties of an interacting quantum gas by creating experimental realizations of continuous matrix product states—a class of states that has proven extremely powerful as a variational ansatz for numerical simulations. By systematically preparing and probing these states using a circuit quantum electrodynamics system, we experimentally determine a good approximation to the ground-state wave function of the Lieb-Liniger Hamiltonian, which describes an interacting Bose gas in one dimension. Since the simulated Hamiltonian is encoded in the measurement observable rather than the controlled quantum system, this approach has the potential to apply to a variety of models including those involving multicomponent interacting fields. Our findings also hint at the possibility of experimentally exploring general properties of matrix product states and entanglement theory. The scheme presented here is applicable to a broad range of systems exploiting strong and tunable light-matter interactions.

An Interactive Care System Based on a Depth Image and EEG for Aged Patients with Dementia

Directory of Open Access Journals (Sweden)

Xin Dang

2017-01-01

Full Text Available Due to the limitations of the body movement and functional decline of the aged with dementia, they can hardly make an efficient communication with nurses by language and gesture language like a normal person. In order to improve the efficiency in the healthcare communication, an intelligent interactive care system is proposed in this paper based on a multimodal deep neural network (DNN. The input vector of the DNN includes motion and mental features and was extracted from a depth image and electroencephalogram that were acquired by Kinect and OpenBCI, respectively. Experimental results show that the proposed algorithm simplified the process of the recognition and achieved 96.5% and 96.4%, respectively, for the shuffled dataset and 90.9% and 92.6%, respectively, for the continuous dataset in terms of accuracy and recall rate.

Interaction Between Encoding and Retrieval Operations in Cued Recall

Science.gov (United States)

Fisher, Ronald P.; Craik, Fergus I. M.

1977-01-01

Three experiments are described in which the qualitative nature of memorial processing was manipulated at both input (encoding) and output (retrieval). As in earlier research, it was found that retention levels were highest when the same type of information was used as a retrieval cue. Concludes that the notions of encoding specificity and depth…

Effects of soil depth and plant-soil interaction on microbial community in temperate grasslands of northern China.

Science.gov (United States)

Yao, Xiaodong; Zhang, Naili; Zeng, Hui; Wang, Wei

2018-07-15

Although the patterns and drivers of soil microbial community composition are well studied, little is known about the effects of plant-soil interactions and soil depth on soil microbial distribution at a regional scale. We examined 195 soil samples from 13 sites along a climatic transect in the temperate grasslands of northern China to measure the composition of and factors influencing soil microbial communities within a 1-m soil profile. Soil microbial community composition was measured using phospholipid fatty acids (PLFA) analysis. Fungi predominated in topsoil (0-10 cm) and bacteria and actinomycetes in deep soils (40-100 cm), independent of steppe types. This variation was explained by contemporary environmental factors (including above- and below-ground plant biomass, soil physicochemical and climatic factors) >58% in the 0-40 cm of soil depth, but soils. Interestingly, when we considered the interactive effects between plant traits (above ground biomass and root biomass) and soil factors (pH, clay content, and soil total carbon, nitrogen, phosphorous), we observed a significant interaction effect occurring at depths of 10-20 cm soil layer, due to different internal and external factors of the plant-soil system along the soil profile. These results improve understanding of the drivers of soil microbial community composition at regional scales. Copyright © 2018 Elsevier B.V. All rights reserved.

Lepton Flavorful Fifth Force and Depth-Dependent Neutrino Matter Interactions

Energy Technology Data Exchange (ETDEWEB)

Wise, Mark B. [Caltech; Zhang, Yue [Northwestern U.

2018-03-01

We consider a fifth force to be an interaction that couples to matter with a strength that grows with the number of atoms. In addition to competing with the strength of gravity a fifth force can give rise to violations of the equivalence principle. Current long range constraints on the strength and range of fifth forces are very impressive. Amongst possible fifth forces are those that couple to lepton flavorful charges $L_e-L_{\\mu}$ or $L_e-L_{\\tau}$. They have the property that their range and strength are also constrained by neutrino interactions with matter. In this brief note we review the existing constraints on the allowed parameter space in gauged $U(1)_{L_e-L_{\\mu}, L_{\\tau}}$. We find two regions where neutrino oscillation experiments are at the frontier of probing such a new force. In particular, there is an allowed range of parameter space where neutrino matter interactions relevant for long baseline oscillation experiments depend on the depth of the neutrino beam below the surface of the earth.

Application of encoded library technology (ELT) to a protein-protein interaction target: discovery of a potent class of integrin lymphocyte function-associated antigen 1 (LFA-1) antagonists.

Science.gov (United States)

Kollmann, Christopher S; Bai, Xiaopeng; Tsai, Ching-Hsuan; Yang, Hongfang; Lind, Kenneth E; Skinner, Steven R; Zhu, Zhengrong; Israel, David I; Cuozzo, John W; Morgan, Barry A; Yuki, Koichi; Xie, Can; Springer, Timothy A; Shimaoka, Motomu; Evindar, Ghotas

2014-04-01

The inhibition of protein-protein interactions remains a challenge for traditional small molecule drug discovery. Here we describe the use of DNA-encoded library technology for the discovery of small molecules that are potent inhibitors of the interaction between lymphocyte function-associated antigen 1 and its ligand intercellular adhesion molecule 1. A DNA-encoded library with a potential complexity of 4.1 billion compounds was exposed to the I-domain of the target protein and the bound ligands were affinity selected, yielding an enriched small-molecule hit family. Compounds representing this family were synthesized without their DNA encoding moiety and found to inhibit the lymphocyte function-associated antigen 1/intercellular adhesion molecule-1 interaction with submicromolar potency in both ELISA and cell adhesion assays. Re-synthesized compounds conjugated to DNA or a fluorophore were demonstrated to bind to cells expressing the target protein. Copyright © 2014 Elsevier Ltd. All rights reserved.

False recognition depends on depth of prior word processing: a magnetoencephalographic (MEG) study.

Science.gov (United States)

Walla, P; Hufnagl, B; Lindinger, G; Deecke, L; Imhof, H; Lang, W

2001-04-01

Brain activity was measured with a whole head magnetoencephalograph (MEG) during the test phases of word recognition experiments. Healthy young subjects had to discriminate between previously presented and new words. During prior study phases two different levels of word processing were provided according to two different kinds of instructions (shallow and deep encoding). Event-related fields (ERFs) associated with falsely recognized words (false alarms) were found to depend on the depth of processing during the prior study phase. False alarms elicited higher brain activity (as reflected by dipole strength) in case of prior deep encoding as compared to shallow encoding between 300 and 500 ms after stimulus onset at temporal brain areas. Between 500 and 700 ms we found evidence for differences in the involvement of neural structures related to both conditions of false alarms. Furthermore, the number of false alarms was found to depend on depth of processing. Shallow encoding led to a higher number of false alarms than deep encoding. All data are discussed as strong support for the ideas that a certain level of word processing is performed by a distinct set of neural systems and that the same neural systems which encode information are reactivated during the retrieval.

Correcting false information in memory: manipulating the strength of misinformation encoding and its retraction.

Science.gov (United States)

Ecker, Ullrich K H; Lewandowsky, Stephan; Swire, Briony; Chang, Darren

2011-06-01

Information that is presumed to be true at encoding but later on turns out to be false (i.e., misinformation) often continues to influence memory and reasoning. In the present study, we investigated how the strength of encoding and the strength of a later retraction of the misinformation affect this continued influence effect. Participants read an event report containing misinformation and a subsequent correction. Encoding strength of the misinformation and correction were orthogonally manipulated either via repetition (Experiment 1) or by imposing a cognitive load during reading (Experiment 2). Results suggest that stronger retractions are effective in reducing the continued influence effects associated with strong misinformation encoding, but that even strong retractions fail to eliminate continued influence effects associated with relatively weak encoding. We present a simple computational model based on random sampling that captures this effect pattern, and conclude that the continued influence effect seems to defy most attempts to eliminate it.

Radon depth migration

International Nuclear Information System (INIS)

Hildebrand, S.T.; Carroll, R.J.

1993-01-01

A depth migration method is presented that used Radon-transformed common-source seismograms as input. It is shown that the Radon depth migration method can be extended to spatially varying velocity depth models by using asymptotic ray theory (ART) to construct wavefield continuation operators. These operators downward continue an incident receiver-array plane wave and an assumed point-source wavefield into the subsurface. The migration velocity model is constrain to have longer characteristic wavelengths than the dominant source wavelength such that the ART approximations for the continuation operators are valid. This method is used successfully to migrate two synthetic data examples: (1) a point diffractor, and (2) a dipping layer and syncline interface model. It is shown that the Radon migration method has a computational advantage over the standard Kirchhoff migration method in that fewer rays are computed in a main memory implementation

Study the Effect of Intermittent and Continuous Ponding Depths by Using Different Heads to Leach Water

OpenAIRE

Nesrin J. AL-Mansori

2018-01-01

As results of using water for irrigated lands in a random manner in a time of shortage main water resources, Experimental work carried out to study the effect of continuous and intermittent ponding depth on the leaching processes. Sandy soil used, sourced from Hilla / Al-Jameeya, at Hilla city. Sieve analysis and hydrometer testing used to identify the properties of the soil. A model used with dimensions of 30, 30 and, 70 cm, with two different heads of water. Shatt-Al-Hilla River samples use...

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera

Science.gov (United States)

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G.; Nagarkar, Vivek V.

2011-06-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99 m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional “straight-cut” (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Depth-of-Interaction Compensation Using a Focused-Cut Scintillator for a Pinhole Gamma Camera.

Science.gov (United States)

Alhassen, Fares; Kudrolli, Haris; Singh, Bipin; Kim, Sangtaek; Seo, Youngho; Gould, Robert G; Nagarkar, Vivek V

2011-06-01

Preclinical SPECT offers a powerful means to understand the molecular pathways of drug interactions in animal models by discovering and testing new pharmaceuticals and therapies for potential clinical applications. A combination of high spatial resolution and sensitivity are required in order to map radiotracer uptake within small animals. Pinhole collimators have been investigated, as they offer high resolution by means of image magnification. One of the limitations of pinhole geometries is that increased magnification causes some rays to travel through the detection scintillator at steep angles, introducing parallax errors due to variable depth-of-interaction in scintillator material, especially towards the edges of the detector field of view. These parallax errors ultimately limit the resolution of pinhole preclinical SPECT systems, especially for higher energy isotopes that can easily penetrate through millimeters of scintillator material. A pixellated, focused-cut (FC) scintillator, with its pixels laser-cut so that they are collinear with incoming rays, can potentially compensate for these parallax errors and thus improve the system resolution. We performed the first experimental evaluation of a newly developed focused-cut scintillator. We scanned a Tc-99m source across the field of view of pinhole gamma camera with a continuous scintillator, a conventional "straight-cut" (SC) pixellated scintillator, and a focused-cut scintillator, each coupled to an electron-multiplying charge coupled device (EMCCD) detector by a fiber-optic taper, and compared the measured full-width half-maximum (FWHM) values. We show that the FWHMs of the focused-cut scintillator projections are comparable to the FWHMs of the thinner SC scintillator, indicating the effectiveness of the focused-cut scintillator in compensating parallax errors.

Interaction model of steel ladle of continuous caster in steel works

Directory of Open Access Journals (Sweden)

Huang Bang Fu

2016-01-01

Full Text Available For further research on the precondition and interoperability model of interaction ladles among continuous caster, this article takes steel ladle of Y steel works as the object of research. On the basis of turnover number calculation model of single cast steel ladle, the relationship between cast number and the turnover number and turnover times and last turnover number are further analyzed. The simulation of steel ladle turnover rules was taken on the 2 continuous casters with Gantt chart. After that, the relationships between turnover number and last turnover number and non-turnover number are researched deeply. Combining with the Gantt chart, the expressions of start casting time and empty ladle ending time and heavy ladle starting time were put forward. The precondition of steel ladle interaction is obtained, which means the exchange ladle should not undertaking transport task in first stop continuous caster, and the empty ladle end time of exchange ladle of first stop continuous caster should early than the heavy ladle start time of last stop continuous caster. After applying the model to practice, 3 steel ladles of No.2 continuous caster can be reduced. This research results is supplying theoretical basis for steel ladle controlling and production organization optimization, and enriches the theory and method of metallurgical process integration.

A method for correcting the depth-of-interaction blurring in PET cameras

International Nuclear Information System (INIS)

Rogers, J.G.

1993-11-01

A method is presented for the purpose of correcting PET images for the blurring caused by variations in the depth-of-interaction in position-sensitive gamma ray detectors. In the case of a fine-cut 50x50x30 mm BGO block detector, the method is shown to improve the detector resolution by about 25%, measured in the geometry corresponding to detection at the edge of the field-of-view. Strengths and weaknesses of the method are discussed and its potential usefulness for improving the images of future PET cameras is assessed. (author). 8 refs., 3 figs

Edge-preserving Intra Depth Coding based on Context-coding and H.264/AVC

DEFF Research Database (Denmark)

Zamarin, Marco; Salmistraro, Matteo; Forchhammer, Søren

2013-01-01

Depth map coding plays a crucial role in 3D Video communication systems based on the “Multi-view Video plus Depth” representation as view synthesis performance is strongly affected by the accuracy of depth information, especially at edges in the depth map image. In this paper an efficient algorithm...... for edge-preserving intra depth compression based on H.264/AVC is presented. The proposed method introduces a new Intra mode specifically targeted to depth macroblocks with arbitrarily shaped edges, which are typically not efficiently represented by DCT. Edge macroblocks are partitioned into two regions...... each approximated by a flat surface. Edge information is encoded by means of contextcoding with an adaptive template. As a novel element, the proposed method allows exploiting the edge structure of previously encoded edge macroblocks during the context-coding step to further increase compression...

Position-Sensitive Detector with Depth-of-Interaction Determination for Small Animal PET

CERN Document Server

Fedorov, A; Kholmetsky, A L; Korzhik, M V; Lecoq, P; Lobko, A S; Missevitch, O V; Tkatchev, A

2002-01-01

Crystal arrays made of LSO and LuAP crystals 2x2x10 mm pixels were manufactured for evaluation of detector with depth-of-interaction (DOI) determination capability intended for small animal positron emission tomograph. Position-sensitive LSO/LuAP phoswich DOI detector based on crystal 8x8 arrays and HAMAMATSU R5900-00-M64 position-sensitive multi-anode photomultiplier tube was developed and evaluated. Time resolution was found to be not worse than 1.0 ns FWHM for both layers, and spatial resolution mean value was 1.5 mm FWHM for the center of field-of-view.

Threat of punishment motivates memory encoding via amygdala, not midbrain, interactions with the medial temporal lobe.

Science.gov (United States)

Murty, Vishnu P; Labar, Kevin S; Adcock, R Alison

2012-06-27

Neural circuits associated with motivated declarative encoding and active threat avoidance have both been described, but the relative contribution of these systems to punishment-motivated encoding remains unknown. The current study used functional magnetic resonance imaging in humans to examine mechanisms of declarative memory enhancement when subjects were motivated to avoid punishments that were contingent on forgetting. A motivational cue on each trial informed participants whether they would be punished or not for forgetting an upcoming scene image. Items associated with the threat of shock were better recognized 24 h later. Punishment-motivated enhancements in subsequent memory were associated with anticipatory activation of right amygdala and increases in its functional connectivity with parahippocampal and orbitofrontal cortices. On a trial-by-trial basis, right amygdala activation during the motivational cue predicted hippocampal activation during encoding of the subsequent scene; across participants, the strength of this interaction predicted memory advantages due to motivation. Of note, punishment-motivated learning was not associated with activation of dopaminergic midbrain, as would be predicted by valence-independent models of motivation to learn. These data are consistent with the view that motivation by punishment activates the amygdala, which in turn prepares the medial temporal lobe for memory formation. The findings further suggest a brain system for declarative learning motivated by punishment that is distinct from that for learning motivated by reward.

Role of the interaction processes in the depth-dose distribution of proton beams in liquid water

International Nuclear Information System (INIS)

Garcia-Molina, Rafael; Abril, Isabel; De Vera, Pablo; Kyriakou, Ioanna; Emfietzoglou, Dimitris

2012-01-01

We use a simulation code, based on Molecular Dynamics and Monte Carlo, to investigate the depth-dose profile and lateral radial spreading of swift proton beams in liquid water. The stochastic nature of the projectile-target interaction is accounted for in a detailed manner by including in a consistent way fluctuations in both the energy loss due to inelastic collisions and the angular deflection from multiple elastic scattering. Depth-variation of the projectile charge-state as it slows down into the target, due to electron capture and loss processes, is also considered. By selectively switching on/off these stochastic processes in the simulation, we evaluate the contribution of each one of them to the Bragg curve. Our simulations show that the inclusion of the energy-loss straggling sizeably affects the width of the Bragg peak, whose position is mainly determined by the stopping power. The lateral spread of the beam as a function of the depth in the target is also examined.

Texture side information generation for distributed coding of video-plus-depth

DEFF Research Database (Denmark)

Salmistraro, Matteo; Raket, Lars Lau; Zamarin, Marco

2013-01-01

We consider distributed video coding in a monoview video-plus-depth scenario, aiming at coding textures jointly with their corresponding depth stream. Distributed Video Coding (DVC) is a video coding paradigm in which the complexity is shifted from the encoder to the decoder. The Side Information...... components) is strongly correlated, so the additional depth information may be used to generate more accurate SI for the texture stream, increasing the efficiency of the system. In this paper we propose various methods for accurate texture SI generation, comparing them with other state-of-the-art solutions...

Exploration of depth modeling mode one lossless wedgelets storage strategies for 3D-high efficiency video coding

Science.gov (United States)

Sanchez, Gustavo; Marcon, César; Agostini, Luciano Volcan

2018-01-01

The 3D-high efficiency video coding has introduced tools to obtain higher efficiency in 3-D video coding, and most of them are related to the depth maps coding. Among these tools, the depth modeling mode-1 (DMM-1) focuses on better encoding edges regions of depth maps. The large memory required for storing all wedgelet patterns is one of the bottlenecks in the DMM-1 hardware design of both encoder and decoder since many patterns must be stored. Three algorithms to reduce the DMM-1 memory requirements and a hardware design targeting the most efficient among these algorithms are presented. Experimental results demonstrate that the proposed solutions surpass related works reducing up to 78.8% of the wedgelet memory, without degrading the encoding efficiency. Synthesis results demonstrate that the proposed algorithm reduces almost 75% of the power dissipation when compared to the standard approach.

Efficient depth intraprediction method for H.264/AVC-based three-dimensional video coding

Science.gov (United States)

Oh, Kwan-Jung; Oh, Byung Tae

2015-04-01

We present an intracoding method that is applicable to depth map coding in multiview plus depth systems. Our approach combines skip prediction and plane segmentation-based prediction. The proposed depth intraskip prediction uses the estimated direction at both the encoder and decoder, and does not need to encode residual data. Our plane segmentation-based intraprediction divides the current block into biregions, and applies a different prediction scheme for each segmented region. This method avoids incorrect estimations across different regions, resulting in higher prediction accuracy. Simulation results demonstrate that the proposed scheme is superior to H.264/advanced video coding intraprediction and has the ability to improve the subjective rendering quality.

Cellular dynamical mechanisms for encoding the time and place of events along spatiotemporal trajectories in episodic memory.

Science.gov (United States)

Hasselmo, Michael E; Giocomo, Lisa M; Brandon, Mark P; Yoshida, Motoharu

2010-12-31

Understanding the mechanisms of episodic memory requires linking behavioral data and lesion effects to data on the dynamics of cellular membrane potentials and population interactions within brain regions. Linking behavior to specific membrane channels and neurochemicals has implications for therapeutic applications. Lesions of the hippocampus, entorhinal cortex and subcortical nuclei impair episodic memory function in humans and animals, and unit recording data from these regions in behaving animals indicate episodic memory processes. Intracellular recording in these regions demonstrates specific cellular properties including resonance, membrane potential oscillations and bistable persistent spiking that could underlie the encoding and retrieval of episodic trajectories. A model presented here shows how intrinsic dynamical properties of neurons could mediate the encoding of episodic memories as complex spatiotemporal trajectories. The dynamics of neurons allow encoding and retrieval of unique episodic trajectories in multiple continuous dimensions including temporal intervals, personal location, the spatial coordinates and sensory features of perceived objects and generated actions, and associations between these elements. The model also addresses how cellular dynamics could underlie unit firing data suggesting mechanisms for coding continuous dimensions of space, time, sensation and action. Copyright © 2010 Elsevier B.V. All rights reserved.

Impact of interspecific interactions on the soil water uptake depth in a young temperate mixed species plantation

Science.gov (United States)

Grossiord, Charlotte; Gessler, Arthur; Granier, André; Berger, Sigrid; Bréchet, Claude; Hentschel, Rainer; Hommel, Robert; Scherer-Lorenzen, Michael; Bonal, Damien

2014-11-01

Interactions between tree species in forests can be beneficial to ecosystem functions and services related to the carbon and water cycles by improving for example transpiration and productivity. However, little is known on below- and above-ground processes leading to these positive effects. We tested whether stratification in soil water uptake depth occurred between four tree species in a 10-year-old temperate mixed species plantation during a dry summer. We selected dominant and co-dominant trees of European beech, Sessile oak, Douglas fir and Norway spruce in areas with varying species diversity, competition intensity, and where different plant functional types (broadleaf vs. conifer) were present. We applied a deuterium labelling approach that consisted of spraying labelled water to the soil surface to create a strong vertical gradient of the deuterium isotope composition in the soil water. The deuterium isotope composition of both the xylem sap and the soil water was measured before labelling, and then again three days after labelling, to estimate the soil water uptake depth using a simple modelling approach. We also sampled leaves and needles from selected trees to measure their carbon isotope composition (a proxy for water use efficiency) and total nitrogen content. At the end of the summer, we found differences in the soil water uptake depth between plant functional types but not within types: on average, coniferous species extracted water from deeper layers than did broadleaved species. Neither species diversity nor competition intensity had a detectable influence on soil water uptake depth, foliar water use efficiency or foliar nitrogen concentration in the species studied. However, when coexisting with an increasing proportion of conifers, beech extracted water from progressively deeper soil layers. We conclude that complementarity for water uptake could occur in this 10-year-old plantation because of inherent differences among functional groups (conifers

Continuous atom laser with Bose-Einstein condensates involving three-body interactions

Energy Technology Data Exchange (ETDEWEB)

Carpentier, A V; Michinel, H; Novoa, D [Area de Optica, Facultade de Ciencias de Ourense, Universidade de Vigo, As Lagoas s/n, Ourense, ES-32004 (Spain); Olivieri, D N, E-mail: avcarpentier@uvigo.e [Area de Linguaxes e sistemas informaticos, Escola Superior de EnxenerIa Informatica, Universidade de Vigo, As Lagoas s/n, Ourense, ES-32004 (Spain)

2010-05-28

We demonstrate, through numerical simulations, the emission of a coherent continuous matter wave of constant amplitude from a Bose-Einstein condensate in a shallow optical dipole trap. The process is achieved by spatial control of the variations of the scattering length along the trapping axis, including elastic three-body interactions due to dipole interactions. In our approach, the outcoupling mechanism is atomic interactions, and thus, the trap remains unaltered. We calculate analytically the parameters for the experimental implementation of this continuous wave atom laser.

Towards PDT with Genetically Encoded Photosensitizer KillerRed: A Comparison of Continuous and Pulsed Laser Regimens in an Animal Tumor Model.

Directory of Open Access Journals (Sweden)

Marina Shirmanova

Full Text Available The strong phototoxicity of the red fluorescent protein KillerRed allows it to be considered as a potential genetically encoded photosensitizer for the photodynamic therapy (PDT of cancer. The advantages of KillerRed over chemical photosensitizers are its expression in tumor cells transduced with the appropriate gene and direct killing of cells through precise damage to any desired cell compartment. The ability of KillerRed to affect cell division and to induce cell death has already been demonstrated in cancer cell lines in vitro and HeLa tumor xenografts in vivo. However, the further development of this approach for PDT requires optimization of the method of treatment. In this study we tested the continuous wave (593 nm and pulsed laser (584 nm, 10 Hz, 18 ns modes to achieve an antitumor effect. The research was implemented on CT26 subcutaneous mouse tumors expressing KillerRed in fusion with histone H2B. The results showed that the pulsed mode provided a higher rate of photobleaching of KillerRed without any temperature increase on the tumor surface. PDT with the continuous wave laser was ineffective against CT26 tumors in mice, whereas the pulsed laser induced pronounced histopathological changes and inhibition of tumor growth. Therefore, we selected an effective regimen for PDT when using the genetically encoded photosensitizer KillerRed and pulsed laser irradiation.

Algebraic 2D PET image reconstruction using depth-of-interaction information

International Nuclear Information System (INIS)

Yamaya, Taiga; Obi, Takashi; Yamaguchi, Masahiro; Kita, Kouichi

2001-01-01

Recently a high-performance PET scanner, which measures depth-of-interaction (DOI) information, is being developed for molecular imaging. DOI measurement of multi-layered thin crystals can improve spatial resolution and scanner sensitivity simultaneously. In this paper, we apply an algebraic image reconstruction method to 2-dimensional (2D) DOI-PET scanners using accurate system modeling, in order to evaluate the effects of using DOI information on PET image quality. Algebraic image reconstruction methods have been successfully used to improve PET image quality, compared with the conventional filtered backprojection method. The proposed method is applied to simulated data for a small 2D DOI-PET scanner. The results show that accurate system modeling improves spatial resolution without noise emphasis, and that DOI information improves uniformity of spatial resolution. (author)

An encoding device and a method of encoding

DEFF Research Database (Denmark)

2012-01-01

The present invention relates to an encoding device, such as an optical position encoder, for encoding input from an object, and a method for encoding input from an object, for determining a position of an object that interferes with light of the device. The encoding device comprises a light source...... in the area in the space and may interfere with the light, which interference may be encoded into a position or activation....

Interaction between litter quality and simulated water depth on decomposition of two emergent macrophytes

Directory of Open Access Journals (Sweden)

Yajun Xie

2015-07-01

Full Text Available Both water depth and litter quality are important factors influencing litter decomposition in wetlands, but the interactive role of these factors in regulating mass loss and nutrient dynamics is far from clear. The responses of mass loss and nutrient dynamics to simulated water depths and litter quality are investigated in leaves of Carex brevicuspis and leaves and stems of Miscanthus sacchariflorus from the Dongting Lake, China. Three litter types differing in litter quality were incubated for 210 days at three water depths (0 cm, 5 cm, and 80 cm, relative to the water surface in a pond near the Dongting Lake. The litter mass remaining, nitrogen (N, phosphorus (P, organic carbon (organic C, cellulose, and lignin contents were analyzed during the controlled decomposition experiment. Moreover, water properties (temperature, dissolved oxygen content, and conductivity and fungal biomass were also characterized. Initial N and P contents were highest in C. brevicuspis leaves, intermediate in M. sacchariflorus leaves and lowest in M. sacchariflorus stems, whereas the organic C, cellulose, and lignin contents exhibited an opposite trend. After a 210 days incubation, decomposition rate was highest in M. sacchariflorus leaves (0.0034–0.0090 g g-1 DW day-1, in exponential decay model, intermediate in C. brevicuspis leaves (0.0019–0.0041 g g-1 DW day-1, and lowest in M. sacchariflorus stems (0.0005–0.0011 g g-1DW day-1. Decomposition rate of C. brevicuspis leaves was highest at 5 cm water depth, intermediate at 80 cm, and lowest at 0 cm. Decomposition rate of M. sacchariflorus leaves was higher at 5 cm, and 80 cm than at 0 cm water depths. Water depth had no effect on decomposition of M. sacchariflorus stems. At the end of incubation, N and P mineralization was completely in leaf litters with increasing rates along with increasing water depth, while nutrients were accumulated in M. sacchariflorus stem. Organic C, cellulose, and lignin decayed quickly

Sleep depth and continuity before and after chronic exercise in older men: electrophysiological evidence.

Science.gov (United States)

Melancon, Michel O; Lorrain, Dominique; Dionne, Isabelle J

2015-03-01

During later life sleep depth (slow-wave sleep, SWS) and maintenance exhibit deleterious changes, with possible negative effects on daytime function. This study assessed the effect of chronic, supervised exercise on sleep using laboratory-based polysomnography (PSG) and repeated measures in older adults. Thirteen men aged 64±3served as their own controls and had their sleep measured for a total of 6 nights: 3 before and 3 after the 16-week training intervention. Each sequence involved 1 familiarization trial followed by 2 experimental nights (exercise night; nonexercise night) measured using 13-channel PSG (combined electroencephalography, electromyography, and electro-oculography). The exercise challenges consisted of inclined treadmill brisk walking (60min, 68-69% V˙O2peak). The intervention successfully improved some parameters of aerobic fitness, i.e. ventilatory thresholds 1 and 2 (Pcontinuity by decreasing total wake time. These results show that aerobic training could increase sleep depth and continuity, during active days, in elderly men. In habitual exercisers, these effects of aerobic exercise on sleep, although modest, might counteract those resulting from aging. Copyright © 2015 Elsevier Inc. All rights reserved.

Proteins Encoded in Genomic Regions Associated with Immune-Mediated Disease Physically Interact and Suggest Underlying Biology

Science.gov (United States)

Rossin, Elizabeth J.; Lage, Kasper; Raychaudhuri, Soumya; Xavier, Ramnik J.; Tatar, Diana; Benita, Yair

2011-01-01

Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed by these risk variants. It has previously been observed that different genes harboring causal mutations for the same Mendelian disease often physically interact. We sought to evaluate the degree to which this is true of genes within strongly associated loci in complex disease. Using sets of loci defined in rheumatoid arthritis (RA) and Crohn's disease (CD) GWAS, we build protein–protein interaction (PPI) networks for genes within associated loci and find abundant physical interactions between protein products of associated genes. We apply multiple permutation approaches to show that these networks are more densely connected than chance expectation. To confirm biological relevance, we show that the components of the networks tend to be expressed in similar tissues relevant to the phenotypes in question, suggesting the network indicates common underlying processes perturbed by risk loci. Furthermore, we show that the RA and CD networks have predictive power by demonstrating that proteins in these networks, not encoded in the confirmed list of disease associated loci, are significantly enriched for association to the phenotypes in question in extended GWAS analysis. Finally, we test our method in 3 non-immune traits to assess its applicability to complex traits in general. We find that genes in loci associated to height and lipid levels assemble into significantly connected networks but did not detect excess connectivity among Type 2 Diabetes (T2D) loci beyond chance. Taken together, our results constitute evidence that, for many of the complex diseases studied here, common genetic associations implicate regions encoding proteins that physically interact in a preferential manner, in

Fast Coding Unit Encoding Mechanism for Low Complexity Video Coding

OpenAIRE

Gao, Yuan; Liu, Pengyu; Wu, Yueying; Jia, Kebin; Gao, Guandong

2016-01-01

In high efficiency video coding (HEVC), coding tree contributes to excellent compression performance. However, coding tree brings extremely high computational complexity. Innovative works for improving coding tree to further reduce encoding time are stated in this paper. A novel low complexity coding tree mechanism is proposed for HEVC fast coding unit (CU) encoding. Firstly, this paper makes an in-depth study of the relationship among CU distribution, quantization parameter (QP) and content ...

The role of encoding and attention in facial emotion memory: an EEG investigation.

Science.gov (United States)

Brenner, Colleen A; Rumak, Samuel P; Burns, Amy M N; Kieffaber, Paul D

2014-09-01

Facial expressions are encoded via sensory mechanisms, but meaning extraction and salience of these expressions involve cognitive functions. We investigated the time course of sensory encoding and subsequent maintenance in memory via EEG. Twenty-nine healthy participants completed a facial emotion delayed match-to-sample task. P100, N170 and N250 ERPs were measured in response to the first stimulus, and evoked theta power (4-7Hz) was measured during the delay interval. Negative facial expressions produced larger N170 amplitudes and greater theta power early in the delay. N170 amplitude correlated with theta power, however larger N170 amplitude coupled with greater theta power only predicted behavioural performance for one emotion condition (very happy) out of six tested (see Supplemental Data). These findings indicate that the N170 ERP may be sensitive to emotional facial expressions when task demands require encoding and retention of this information. Furthermore, sustained theta activity may represent continued attentional processing that supports short-term memory, especially of negative facial stimuli. Further study is needed to investigate the potential influence of these measures, and their interaction, on behavioural performance. Crown Copyright © 2014. Published by Elsevier B.V. All rights reserved.

Interactions among emotional attention, encoding, and retrieval of ambiguous information: an eye-tracking study

OpenAIRE

Everaert, Jonas; Koster, Ernst

2015-01-01

Emotional biases in attention modulate encoding of emotional material into long-term memory, but little is known about the role of such attentional biases during emotional memory retrieval. The present study investigated how emotional biases in memory are related to attentional allocation during retrieval. Forty-nine individuals encoded emotionally positive and negative meanings derived from ambiguous information and then searched their memory for encoded meanings in response to a set of retr...

Deep--deeper--deepest? Encoding strategies and the recognition of human faces.

Science.gov (United States)

Sporer, S L

1991-03-01

Various encoding strategies that supposedly promote deeper processing of human faces (e.g., character judgments) have led to better recognition than more shallow processing tasks (judging the width of the nose). However, does deeper processing actually lead to an improvement in recognition, or, conversely, does shallow processing lead to a deterioration in performance when compared with naturally employed encoding strategies? Three experiments systematically compared a total of 8 different encoding strategies manipulating depth of processing, amount of elaboration, and self-generation of judgmental categories. All strategies that required a scanning of the whole face were basically equivalent but no better than natural strategy controls. The consistently worst groups were the ones that rated faces along preselected physical dimensions. This can be explained by subjects' lesser task involvement as revealed by manipulation checks.

A room temperature LSO/PIN photodiode PET detector module that measures depth of interaction

International Nuclear Information System (INIS)

Moses, W.W.; Derenzo, S.E.; Melcher, C.L.; Manente, R.A.

1994-11-01

We present measurements of a 4 element PET detector module that uses a 2x2 array of 3 mm square PIN photodiodes to both measure the depth of interaction (DOI) and identify the crystal of interaction. Each photodiode is coupled to one end of a 3x3x25 mm LSO crystal, with the opposite ends of all 4 crystals attached to a single PMT that provides a timing signal and initial energy discrimination. Each LSO crystal is coated with a open-quotes lossyclose quotes reflector, so the ratio of light detected in the photodiode and PMT depends on the position of interaction in the crystal, and is used to determine this position on an event by event basis. This module is operated at +25 degrees C with a photodiode amplifier peaking time of 2 μs. When excited by a collimated beam of 511 keV photons at the photodiode end of the module (i.e. closest to the patient), the DOI resolution is 4 mm fwhm and the crystal of interaction is identified correctly 95% of the time. When excited at the opposite end of the module, the DOI resolution is 13 mm fwhm and the crystal of interaction is identified correctly 73% of the time. The channel to channel variations in performance are minimal

Impact of encoding depth on awareness of perceptual effects in recognition memory.

Science.gov (United States)

Gardiner, J M; Gregg, V H; Mashru, R; Thaman, M

2001-04-01

Pictorial stimuli are more likely to be recognized if they are the same size, rather than a different size, at study and at test. This size congruency effect was replicated in two experiments in which the encoding variables were respectively undivided versus divided attention and level of processing. In terms of performance, these variables influenced recognition and did not influence size congruency effects. But in terms of awareness, measured by remember and know responses, these variables did influence size congruency effects. With undivided attention and with a deep level of processing, size congruency effects occurred only in remembering. With divided attention and with a shallow level of processing, size congruency effects occurred only in knowing. The results show that effects that occur in remembering may also occur independently in knowing. They support theories in which remembering and knowing reflect different memory processes or systems. They do not support the theory that remembering and knowing reflect differences in trace strength.

Interactive Editing of GigaSample Terrain Fields

KAUST Repository

Treib, Marc

2012-05-01

Previous terrain rendering approaches have addressed the aspect of data compression and fast decoding for rendering, but applications where the terrain is repeatedly modified and needs to be buffered on disk have not been considered so far. Such applications require both decoding and encoding to be faster than disk transfer. We present a novel approach for editing gigasample terrain fields at interactive rates and high quality. To achieve high decoding and encoding throughput, we employ a compression scheme for height and pixel maps based on a sparse wavelet representation. On recent GPUs it can encode and decode up to 270 and 730 MPix/s of color data, respectively, at compression rates and quality superior to JPEG, and it achieves more than twice these rates for lossless height field compression. The construction and rendering of a height field triangulation is avoided by using GPU ray-casting directly on the regular grid underlying the compression scheme. We show the efficiency of our method for interactive editing and continuous level-of-detail rendering of terrain fields comprised of several hundreds of gigasamples. © 2012 The Author(s).

Deep and shallow encoding effects on face recognition: an ERP study.

Science.gov (United States)

Marzi, Tessa; Viggiano, Maria Pia

2010-12-01

Event related potentials (ERPs) were employed to investigate whether and when brain activity related to face recognition varies according to the processing level undertaken at encoding. Recognition was assessed when preceded by a "shallow" (orientation judgement) or by a "deep" study task (occupation judgement). Moreover, we included a further manipulation by presenting at encoding faces either in the upright or inverted orientation. As expected, deeply encoded faces were recognized more accurately and more quickly with respect to shallowly encoded faces. The ERP showed three main findings: i) as witnessed by more positive-going potentials for deeply encoded faces, at early and later processing stage, face recognition was influenced by the processing strategy adopted during encoding; ii) structural encoding, indexed by the N170, turned out to be "cognitively penetrable" showing repetition priming effects for deeply encoded faces; iii) face inversion, by disrupting configural processing during encoding, influenced memory related processes for deeply encoded faces and impaired the recognition of faces shallowly processed. The present study adds weight to the concept that the depth of processing during memory encoding affects retrieval. We found that successful retrieval following deep encoding involved both familiarity- and recollection-related processes showing from 500 ms a fronto-parietal distribution, whereas shallow encoding affected only earlier processing stages reflecting perceptual priming. Copyright © 2010 Elsevier B.V. All rights reserved.

Novel nuclear-encoded proteins interacting with a plastid sigma factor, Sig1, in Arabidopsis thaliana.

Science.gov (United States)

Morikawa, Kazuya; Shiina, Takashi; Murakami, Shinya; Toyoshima, Yoshinori

2002-03-13

Sigma factor binding proteins are involved in modifying the promoter preferences of the RNA polymerase in bacteria. We found the nuclear encoded protein (SibI) that is transported into chloroplasts and interacts specifically with the region 4 of Sig1 in Arabidopsis. SibI and its homologue, T3K9.5 are novel proteins, which are not homologous to any protein of known function. The expression of sibI was tissue specific, light dependent, and developmentally timed. We suggest the transcriptional regulation by sigma factor binding proteins to function in the plastids of higher plant.

The continuous tower of scalar fields as a system of interacting dark matter–dark energy

International Nuclear Information System (INIS)

Santos, Paulo

2015-01-01

This paper aims to introduce a new parameterisation for the coupling Q in interacting dark matter and dark energy models by connecting said models with the Continuous Tower of Scalar Fields model. Based upon the existence of a dark matter and a dark energy sectors in the Continuous Tower of Scalar Fields, a simplification is considered for the evolution of a single scalar field from the tower, validated in this paper. This allows for the results obtained with the Continuous Tower of Scalar Fields model to match those of an interacting dark matter–dark energy system, considering that the energy transferred from one fluid to the other is given by the energy of the scalar fields that start oscillating at a given time, rather than considering that the energy transference depends on properties of the whole fluids that are interacting.

Get the gist? The effects of processing depth on false recognition in short-term and long-term memory.

Science.gov (United States)

Flegal, Kristin E; Reuter-Lorenz, Patricia A

2014-07-01

Gist-based processing has been proposed to account for robust false memories in the converging-associates task. The deep-encoding processes known to enhance verbatim memory also strengthen gist memory and increase distortions of long-term memory (LTM). Recent research has demonstrated that compelling false memory illusions are relatively delay-invariant, also occurring under canonical short-term memory (STM) conditions. To investigate the contributions of gist to false memory at short and long delays, processing depth was manipulated as participants encoded lists of four semantically related words and were probed immediately, following a filled 3- to 4-s retention interval, or approximately 20 min later, in a surprise recognition test. In two experiments, the encoding manipulation dissociated STM and LTM on the frequency, but not the phenomenology, of false memory. Deep encoding at STM increases false recognition rates at LTM, but confidence ratings and remember/know judgments are similar across delays and do not differ as a function of processing depth. These results suggest that some shared and some unique processes underlie false memory illusions at short and long delays.

Interactions among emotional attention, encoding, and retrieval of ambiguous information: An eye-tracking study.

Science.gov (United States)

Everaert, Jonas; Koster, Ernst H W

2015-10-01

Emotional biases in attention modulate encoding of emotional material into long-term memory, but little is known about the role of such attentional biases during emotional memory retrieval. The present study investigated how emotional biases in memory are related to attentional allocation during retrieval. Forty-nine individuals encoded emotionally positive and negative meanings derived from ambiguous information and then searched their memory for encoded meanings in response to a set of retrieval cues. The remember/know/new procedure was used to classify memories as recollection-based or familiarity-based, and gaze behavior was monitored throughout the task to measure attentional allocation. We found that a bias in sustained attention during recollection-based, but not familiarity-based, retrieval predicted subsequent memory bias toward positive versus negative material following encoding. Thus, during emotional memory retrieval, attention affects controlled forms of retrieval (i.e., recollection) but does not modulate relatively automatic, familiarity-based retrieval. These findings enhance understanding of how distinct components of attention regulate the emotional content of memories. Implications for theoretical models and emotion regulation are discussed. (c) 2015 APA, all rights reserved).

Continuous approximation for interaction energy of adamantane encapsulated inside carbon nanotubes

Science.gov (United States)

Baowan, Duangkamon; Hill, James M.; Bacsa, Wolfgang

2018-02-01

The interaction energy for two adjacent adamantane molecules and that of adamantane molecules encapsulated inside carbon nanotubes are investigated considering only dipole-dipole induced interaction. The Lennard-Jones potential and the continuous approximation are utilised to derive analytical expressions for these interaction energies. The equilibrium distance 3.281 Å between two adamantane molecules is determined. The smallest carbon nanotube radius b0 that can encapsulate the adamantane molecule and the radius of the tube bmax that gives the maximum suction energy, linearly depend on the adamantane radius, are calculated. For larger diameter tubes, the off axis position has been calculated, and equilibrium distance between molecule and tube wall is found to be close to the interlayer spacing in graphene.

rigor mortis encodes a novel nuclear receptor interacting protein required for ecdysone signaling during Drosophila larval development.

Science.gov (United States)

Gates, Julie; Lam, Geanette; Ortiz, José A; Losson, Régine; Thummel, Carl S

2004-01-01

Pulses of the steroid hormone ecdysone trigger the major developmental transitions in Drosophila, including molting and puparium formation. The ecdysone signal is transduced by the EcR/USP nuclear receptor heterodimer that binds to specific response elements in the genome and directly regulates target gene transcription. We describe a novel nuclear receptor interacting protein encoded by rigor mortis (rig) that is required for ecdysone responses during larval development. rig mutants display defects in molting, delayed larval development, larval lethality, duplicated mouth parts, and defects in puparium formation--phenotypes that resemble those seen in EcR, usp, E75A and betaFTZ-F1 mutants. Although the expression of these nuclear receptor genes is essentially normal in rig mutant larvae, the ecdysone-triggered switch in E74 isoform expression is defective. rig encodes a protein with multiple WD-40 repeats and an LXXLL motif, sequences that act as specific protein-protein interaction domains. Consistent with the presence of these elements and the lethal phenotypes of rig mutants, Rig protein interacts with several Drosophila nuclear receptors in GST pull-down experiments, including EcR, USP, DHR3, SVP and betaFTZ-F1. The ligand binding domain of betaFTZ-F1 is sufficient for this interaction, which can occur in an AF-2-independent manner. Antibody stains reveal that Rig protein is present in the brain and imaginal discs of second and third instar larvae, where it is restricted to the cytoplasm. In larval salivary gland and midgut cells, however, Rig shuttles between the cytoplasm and nucleus in a spatially and temporally regulated manner, at times that correlate with the major lethal phase of rig mutants and major switches in ecdysone-regulated gene expression. Taken together, these data indicate that rig exerts essential functions during larval development through gene-specific effects on ecdysone-regulated transcription, most likely as a cofactor for one or more

Continuous unitary transformation approach to pairing interactions in statistical physics

Directory of Open Access Journals (Sweden)

T.Domański

2008-06-01

Full Text Available We apply the flow equation method to the study of the fermion systems with pairing interactions which lead to the BCS instability signalled by the appearance of the off-diagonal order parameter. For this purpose we rederive the continuous Bogoliubov transformation in a fashion of renormalization group procedure where the low and high energy sectors are treated subsequently. We further generalize this procedure to the case of fermions interacting with the discrete boson mode. Andreev-type interactions are responsible for developing a gap in the excitation spectrum. However, the long-range coherence is destroyed due to strong quantum fluctuations.

Energy resolution of a four-layer depth of interaction detector block for small animal PET

International Nuclear Information System (INIS)

Tsuda, Tomoaki; Kawai, Hideyuki; Orita, Narimichi; Murayama, Hideo; Yoshida, Eiji; Inadama, Naoko; Yamaya, Taiga; Omura, Tomohide

2004-01-01

We are now planning to develop a positron emission tomograph dedicated to small animals such as rats and mice which meets the demand for higher sensitivity. We proposed a new depth of interaction (DOI) detector arrangement to obtain DOI information by using a four-layer detector with all the same crystal elements. In this DOI detector, we control the behavior of scintillation photons by inserting the reflectors between crystal elements so that the DOI information of four layers can be extracted from one two-dimensional (2D) position histogram made by Anger-type calculation. In this work, we evaluate the energy resolution of this four-layer DOI detector. (author)

Continued use of an interactive computer game-based visual perception learning system in children with developmental delay.

Science.gov (United States)

Lin, Hsien-Cheng; Chiu, Yu-Hsien; Chen, Yenming J; Wuang, Yee-Pay; Chen, Chiu-Ping; Wang, Chih-Chung; Huang, Chien-Ling; Wu, Tang-Meng; Ho, Wen-Hsien

2017-11-01

This study developed an interactive computer game-based visual perception learning system for special education children with developmental delay. To investigate whether perceived interactivity affects continued use of the system, this study developed a theoretical model of the process in which learners decide whether to continue using an interactive computer game-based visual perception learning system. The technology acceptance model, which considers perceived ease of use, perceived usefulness, and perceived playfulness, was extended by integrating perceived interaction (i.e., learner-instructor interaction and learner-system interaction) and then analyzing the effects of these perceptions on satisfaction and continued use. Data were collected from 150 participants (rehabilitation therapists, medical paraprofessionals, and parents of children with developmental delay) recruited from a single medical center in Taiwan. Structural equation modeling and partial-least-squares techniques were used to evaluate relationships within the model. The modeling results indicated that both perceived ease of use and perceived usefulness were positively associated with both learner-instructor interaction and learner-system interaction. However, perceived playfulness only had a positive association with learner-system interaction and not with learner-instructor interaction. Moreover, satisfaction was positively affected by perceived ease of use, perceived usefulness, and perceived playfulness. Thus, satisfaction positively affects continued use of the system. The data obtained by this study can be applied by researchers, designers of computer game-based learning systems, special education workers, and medical professionals. Copyright © 2017 Elsevier B.V. All rights reserved.

Interpretation of Simulations in Interactive VR Environments: Depth Perception in Cave and Panorama

DEFF Research Database (Denmark)

Mullins, Michael

2006-01-01

 Virtual reality (VR) applications are transforming the way architecture is conceived and produced. By introducing an open and inclusive approach, they encourage a creative dialogue with the users of residential schemes and other buildings and allow competition juries a more thorough understanding...... of architectural concepts. Architects need to heed the dynamics set in motion by these technologies and especially of how laypersons interpret building forms and their simulations in interactive VR environments. The article presents a study which compares aspects of spatial perception in a physical environment...... contextual experience of the viewer, and that spatial ability is an important contributing factor. Results in the two virtual environments tested show consistent differences in how depth and shape are perceived, indicating that VR context is a significant variable in spatial representation. It is asserted...

Study the Effect of Intermittent and Continuous Ponding Depths by Using Different Heads to Leach Water

Directory of Open Access Journals (Sweden)

Nesrin J. AL-Mansori

2018-03-01

Full Text Available As results of using water for irrigated lands in a random manner in a time of shortage main water resources, Experimental work carried out to study the effect of continuous and intermittent ponding depth on the leaching processes. Sandy soil used, sourced from Hilla / Al-Jameeya, at Hilla city. Sieve analysis and hydrometer testing used to identify the properties of the soil. A model used with dimensions of 30, 30 and, 70 cm, with two different heads of water. Shatt-Al-Hilla River samples used in the leaching process.   Chemical tests carried out before the leaching process to identify changes in the proprieties in both water and soil. Leachate collected from two soil columns drained into boxes and tests carried out every 30 minutes. After the leaching process was complete, the soil was re-tested. Chemical tests on soil samples and the collected water applied after leaching for 47.5 cm and 52.5cm heads. From the results،, it can be notice that electrical conductivity for the outlet discharge from soil samples decreased faster with time, then slowing down until the end of leaching process.  The same pattern can be seen for all soil properties. In continuous leaching, a large quantity of water is required over a short leaching period, the inverse true for intermittent leaching. All parameters reduce with time in continuous leaching in comparison to intermittent leaching but when the water level in the soil column compared, it can inferred that increasing the head will reduce all the parameters for soil.

A Frequency-Depth Explicit Interaction Theory Formulation

DEFF Research Database (Denmark)

Ruiz, Pau Mercadé; Ferri, Francesco; Kofoed, Jens Peter

2016-01-01

An alternative definition of the usual diffraction transfer matrix defined by Kagemoto and Yue (1986) has been developed. A method is thereby presented which enables the prediction of the diffraction transfer matrix for any desired wave frequency and water depth. The method has been tested for th...

Quantum finite-depth memory channels: Case study

International Nuclear Information System (INIS)

Rybar, Tomas; Ziman, Mario

2009-01-01

We analyze the depth of the memory of quantum memory channels generated by a fixed unitary transformation describing the interaction between the principal system and internal degrees of freedom of the process device. We investigate the simplest case of a qubit memory channel with a two-level memory system. In particular, we explicitly characterize all interactions for which the memory depth is finite. We show that the memory effects are either infinite, or they disappear after at most two uses of the channel. Memory channels of finite depth can be to some extent controlled and manipulated by so-called reset sequences. We show that actions separated by the sequences of inputs of the length of the memory depth are independent and constitute memoryless channels.

Hippocampal-medial prefrontal circuit supports memory updating during learning and post-encoding rest

Science.gov (United States)

Schlichting, Margaret L.; Preston, Alison R.

2015-01-01

Learning occurs in the context of existing memories. Encountering new information that relates to prior knowledge may trigger integration, whereby established memories are updated to incorporate new content. Here, we provide a critical test of recent theories suggesting hippocampal (HPC) and medial prefrontal (MPFC) involvement in integration, both during and immediately following encoding. Human participants with established memories for a set of initial (AB) associations underwent fMRI scanning during passive rest and encoding of new related (BC) and unrelated (XY) pairs. We show that HPC-MPFC functional coupling during learning was more predictive of trial-by-trial memory for associations related to prior knowledge relative to unrelated associations. Moreover, the degree to which HPC-MPFC functional coupling was enhanced following overlapping encoding was related to memory integration behavior across participants. We observed a dissociation between anterior and posterior MPFC, with integration signatures during post-encoding rest specifically in the posterior subregion. These results highlight the persistence of integration signatures into post-encoding periods, indicating continued processing of interrelated memories during rest. We also interrogated the coherence of white matter tracts to assess the hypothesis that integration behavior would be related to the integrity of the underlying anatomical pathways. Consistent with our predictions, more coherent HPC-MPFC white matter structure was associated with better performance across participants. This HPC-MPFC circuit also interacted with content-sensitive visual cortex during learning and rest, consistent with reinstatement of prior knowledge to enable updating. These results show that the HPC-MPFC circuit supports on- and offline integration of new content into memory. PMID:26608407

Design and simulation of a novel method for determining depth-of-interaction in a PET scintillation crystal array using a single-ended readout by a multi-anode PMT

International Nuclear Information System (INIS)

Ito, Mikiko; Sim, Kwang-Souk; Lee, Jae Sung; Park, Min-Jae; Hong, Seong Jong

2010-01-01

PET detectors with depth-of-interaction (DOI) encoding capability allow high spatial resolution and high sensitivity to be achieved simultaneously. To obtain DOI information from a mono-layer array of scintillation crystals using a single-ended readout, the authors devised a method based on light spreading within a crystal array and performed Monte Carlo simulations with individual scintillation photon tracking to prove the concept. A scintillation crystal array model was constructed using a grid method. Conventional grids are constructed using comb-shaped reflector strips with rectangular teeth to isolate scintillation crystals optically. However, the authors propose the use of triangularly shaped teeth, such that scintillation photons spread only in the x-direction in the upper halves of crystals and in the y-direction in lower halves. DOI positions can be estimated by considering the extent of two-dimensional light dispersion, which can be determined from the multiple anode outputs of a position-sensitive PMT placed under the crystal array. In the main simulation, a crystal block consisting of a 29 x 29 array of 1.5 mm x 1.5 mm x 20 mm crystals and a multi-anode PMT with 16 x 16 pixels were used. The effects of crystal size and non-uniform PMT output gain were also explored by simulation. The DOI resolution estimated for 1.5 x 1.5 x 20 mm 3 crystals was 2.16 mm on average. Although the flood map was depth dependent, each crystal was well identified at all depths when a corner of the crystal array was irradiated with 511 keV gamma rays (peak-to-valley ratio ∼9:1). DOI resolution was better than 3 mm up to a crystal length of 28 mm with a 1.5 x 1.5 mm 2 or 2.0 x 2.0 mm 2 crystal surface area. The devised light-sharing method allowed excellent DOI resolutions to be obtained without the use of dual-ended readout or multiple crystal arrays.

Matching and correlation computations in stereoscopic depth perception.

Science.gov (United States)

Doi, Takahiro; Tanabe, Seiji; Fujita, Ichiro

2011-03-02

A fundamental task of the visual system is to infer depth by using binocular disparity. To encode binocular disparity, the visual cortex performs two distinct computations: one detects matched patterns in paired images (matching computation); the other constructs the cross-correlation between the images (correlation computation). How the two computations are used in stereoscopic perception is unclear. We dissociated their contributions in near/far discrimination by varying the magnitude of the disparity across separate sessions. For small disparity (0.03°), subjects performed at chance level to a binocularly opposite-contrast (anti-correlated) random-dot stereogram (RDS) but improved their performance with the proportion of contrast-matched (correlated) dots. For large disparity (0.48°), the direction of perceived depth reversed with an anti-correlated RDS relative to that for a correlated one. Neither reversed nor normal depth was perceived when anti-correlation was applied to half of the dots. We explain the decision process as a weighted average of the two computations, with the relative weight of the correlation computation increasing with the disparity magnitude. We conclude that matching computation dominates fine depth perception, while both computations contribute to coarser depth perception. Thus, stereoscopic depth perception recruits different computations depending on the disparity magnitude.

Interaction between attentional systems and episodic memory encoding: the impact of conflict on binding of information.

Science.gov (United States)

Sperduti, Marco; Armougum, Allan; Makowski, Dominique; Blondé, Philippe; Piolino, Pascale

2017-12-01

Episodic memory (EM) is defined as a long-term memory system that stores information that can be retrieved along with details of the context of the original events (binding). Several studies have shown that manipulation of attention during encoding can impact subsequent memory performance. An influential model of attention distinguishes between three partially independent attentional networks: the alerting, the orienting and the executive or conflict resolution component. To date, the impact of the engagement of these sub-systems during encoding on item and relational context binding has not been investigated. Here, we developed a new task combining the Attentional Network Test and an incidental episodic memory encoding task to study this issue. We reported that when the alerting network was not solicited, resolving conflict hindered item encoding. Moreover, resolving conflict, independently of the cueing condition, had a negative impact on context binding. These novel findings could have a potential impact in the understanding EM formation, and memory disorders in different populations, including healthy elderly people.

Grammatical constraints on phonological encoding in speech production.

Science.gov (United States)

Heller, Jordana R; Goldrick, Matthew

2014-12-01

To better understand the influence of grammatical encoding on the retrieval and encoding of phonological word-form information during speech production, we examine how grammatical class constraints influence the activation of phonological neighbors (words phonologically related to the target--e.g., MOON, TWO for target TUNE). Specifically, we compare how neighbors that share a target's grammatical category (here, nouns) influence its planning and retrieval, assessed by picture naming latencies, and phonetic encoding, assessed by word productions in picture names, when grammatical constraints are strong (in sentence contexts) versus weak (bare naming). Within-category (noun) neighbors influenced planning time and phonetic encoding more strongly in sentence contexts. This suggests that grammatical encoding constrains phonological processing; the influence of phonological neighbors is grammatically dependent. Moreover, effects on planning times could not fully account for phonetic effects, suggesting that phonological interaction affects articulation after speech onset. These results support production theories integrating grammatical, phonological, and phonetic processes.

Interacting Effects Induced by Two Neighboring Pits Considering Relative Position Parameters and Pit Depth

Directory of Open Access Journals (Sweden)

Yongfang Huang

2017-04-01

Full Text Available For pre-corroded aluminum alloy 7075-T6, the interacting effects of two neighboring pits on the stress concentration are comprehensively analyzed by considering various relative position parameters (inclination angle θ and dimensionless spacing parameter λ and pit depth (d with the finite element method. According to the severity of the stress concentration, the critical corrosion regions, bearing high susceptibility to fatigue damage, are determined for intersecting and adjacent pits, respectively. A straightforward approach is accordingly proposed to conservatively estimate the combined stress concentration factor induced by two neighboring pits, and a concrete application example is presented. It is found that for intersecting pits, the normalized stress concentration factor Ktnor increases with the increase of θ and λ and always reaches its maximum at θ = 90°, yet for adjacent pits, Ktnor decreases with the increase of λ and the maximum value appears at a slight asymmetric location. The simulations reveal that Ktnor follows a linear and an exponential relationship with the dimensionless depth parameter Rd for intersecting and adjacent cases, respectively.

The effects of multiview depth video compression on multiview rendering

NARCIS (Netherlands)

Merkle, P.; Morvan, Y.; Smolic, A.; Farin, D.S.; Mueller, K.; With, de P.H.N.; Wiegang, T.

2009-01-01

This article investigates the interaction between different techniques for depth compression and view synthesis rendering with multiview video plus scene depth data. Two different approaches for depth coding are compared, namely H.264/MVC, using temporal and inter-view reference images for efficient

Three-layer GSO depth-of-interaction detector for high-energy gamma camera

International Nuclear Information System (INIS)

Yamamoto, S.; Watabe, H.; Kawachi, N.; Fujimaki, S.; Kato, K.; Hatazawa, J.

2014-01-01

Using Ce-doped Gd 2 SiO 5 (GSO) of different Ce concentrations, three-layer DOI block detectors were developed to reduce the parallax error at the edges of a pinhole gamma camera for high-energy gamma photons. GSOs with Ce concentrations of 1.5 mol% (decay time ∼40 ns), 0.5 mol% crystal (∼60 ns), 0.4 mol% (∼80 ns) were selected for the depth of interaction (DOI) detectors. These three types of GSOs were optically coupled in the depth direction, arranged in a 22×22 matrix and coupled to a flat panel photomultiplier tube (FP-PMT, Hamamatsu H8500). Sizes of these GSO cells were 1.9 mm×1.9 mm×4 mm, 1.9 mm×1.9 mm×5 mm, and 1.9 mm×1.9 mm×6 mm for 1.5 mol%, 0.5 mol%, and 0.4 mol%, respectively. With these combinations of GSOs, all spots corresponding to GSO cells were clearly resolved in the position histogram. Pulse shape spectra showed three peaks for these three decay times of GSOs. The block detector was contained in a 2-cm-thick tungsten shield, and a pinhole collimator with a 0.5-mm aperture was mounted. With pulse shape discrimination, we separated the point source images of the Cs-137 for each DOI layer. The point source image of the lower layer was detected at the most central part of the field-of-view, and the distribution was the smallest. The point source image of the higher layer was detected at the most peripheral part of the field-of-view, and the distribution was widest. With this information, the spatial resolution of the pinhole gamma camera can be improved. We conclude that DOI detection is effective for pinhole gamma cameras for high energy gamma photons

A practical depth-of-interaction PET/MR detector with dichotomous-orthogonal-symmetry decoding

International Nuclear Information System (INIS)

Zhang, Yuxuan; Baghaei, Hossain; Yan, Han; Wong, Wai-Hoi

2015-01-01

Conventional dual-end depth-of-interaction (DOI) PET detector readout requires two 2D SiPM arrays; with top and bottom SiPM reading the same pixel, there is information redundancy. We proposed a dichotomous-orthogonal-symmetric (DOS) dual-end DOI readout to eliminate this redundancy to significantly reduce SiPM usage, electronic channels, and heat load. Reflecting films are used within the scintillator array to channel light exiting the top along the X-direction, while light exiting the bottom is channeled along the orthogonal Y-direction. Despite the unidirectional channeling on each end, the top readout can provide X-Y information using two 1-D SiPM arrays; similarly, the bottom readout also provides X-Y information with two 1-D SiPM arrays. Thus four 1-D SiPM arrays (4xN) are used to decode XYZ to replace two 2D SiPM arrays (2NxN); SiPM usage is reduced from 2N**2 to 4N. Monte Carlo simulations (GATE) were carried out to study the XY decoding accuracy, energy resolution, and DOI resolution. Coupling the DOS-DOI design with a channel-decoding scheme, an array of 15x15 LSO (2.4x2.4x20 mm pixels) can be decoded by 18 SiPMs (2 rows of nine 3x3mm SiPM) on top and 18 SiPMs at bottom, thus achieving a 10X reduction in SiPM usage, electronic channels and heat load. For BGO detectors, an 8x8 array (2.4x2.4x20 mm pixels) can be achieved with 6.4X reduction. Simulations show 5-6mm DOI resolution, 0.45-0.96mm XY decoding blurring, 20-24% energy resolution. This study shows the feasibility of the DOS-DOI design. Even comparing to non-DOI detectors, there is a 5X/3X SiPM reduction for LSO/BGO. The proposed detector may yield practical ultrahigh-resolution PET/MR systems with depth-of-interaction with a production cost below current non-DOI systems.

Deconstructing continuous flash suppression.

Science.gov (United States)

Yang, Eunice; Blake, Randolph

2012-03-08

In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in contrast detection thresholds) as a function of the visual features of the stimulus being suppressed and the stimulus evoking suppression, namely, the popular "Mondrian" CFS stimulus (N. Tsuchiya & C. Koch, 2005). First, we found that CFS differentially suppresses the spatial components of the suppressed stimulus: Observers' sensitivity for stimuli of relatively low spatial frequency or cardinally oriented features was more strongly impaired in comparison to high spatial frequency or obliquely oriented stimuli. Second, we discovered that this feature-selective bias primarily arises from the spatiotemporal structure of the CFS stimulus, particularly within information residing in the low spatial frequency range and within the smooth rather than abrupt luminance changes over time. These results imply that this CFS stimulus operates by selectively attenuating certain classes of low-level signals while leaving others to be potentially encoded during suppression. These findings underscore the importance of considering the contribution of low-level features in stimulus-driven effects that are reported under CFS.

Track-Bridge Longitudinal Interaction of Continuous Welded Rails on Arch Bridge

Directory of Open Access Journals (Sweden)

Rong Chen

2013-01-01

Full Text Available Taking arch bridges, including deck, half-through, and through arch bridges (short for DAB, HTAB, and TAB as examples, mechanics analysis models of longitudinal interaction between continuously welded rails (short for CWRs and arch bridges are established. Based on the finite element method (FEM, the longitudinal interaction calculation software of CWR on arch bridges has been developed. Focusing on an HTAB, the tension, compression, and deflection conditions are calculated and analyzed. The results show that the mechanics analysis models of three types of arch bridges can truly reflect the real state of the structure; the calculation software can be used for systematic research of the CWR on arch bridge; as for HTAB, temperature difference of arch rib has a small effect on rail tension/compression, and arch bridge can be simplified as a continuous beam for rail tension/compression additional force calculation; in calculation of deflection conditions of HTAB, it is suggested that train loads are arranged on half span and full span and take the direction of load entering bridge into account. Additionally, the deflection additional force variation of CFST basket handle arch bridge is different from that of ordinary bridge.

Low-Depth Quantum Simulation of Materials

Directory of Open Access Journals (Sweden)

Ryan Babbush

2018-03-01

Full Text Available Quantum simulation of the electronic structure problem is one of the most researched applications of quantum computing. The majority of quantum algorithms for this problem encode the wavefunction using N Gaussian orbitals, leading to Hamiltonians with O(N^{4} second-quantized terms. We avoid this overhead and extend methods to condensed phase materials by utilizing a dual form of the plane wave basis which diagonalizes the potential operator, leading to a Hamiltonian representation with O(N^{2} second-quantized terms. Using this representation, we can implement single Trotter steps of the Hamiltonians with linear gate depth on a planar lattice. Properties of the basis allow us to deploy Trotter- and Taylor-series-based simulations with respective circuit depths of O(N^{7/2} and O[over ˜](N^{8/3} for fixed charge densities. Variational algorithms also require significantly fewer measurements in this basis, ameliorating a primary challenge of that approach. While our approach applies to the simulation of arbitrary electronic structure problems, the basis sets explored in this work will be most practical for treating periodic systems, such as crystalline materials, in the near term. We conclude with a proposal to simulate the uniform electron gas (jellium using a low-depth variational ansatz realizable on near-term quantum devices. From these results, we identify simulations of low-density jellium as a promising first setting to explore quantum supremacy in electronic structure.

CORTICAL ENCODING OF SIGNALS IN NOISE: EFFECTS OF STIMULUS TYPE AND RECORDING PARADIGM

Science.gov (United States)

Billings, Curtis J.; Bennett, Keri O.; Molis, Michelle R.; Leek, Marjorie R.

2010-01-01

Objectives Perception-in-noise deficits have been demonstrated across many populations and listening conditions. Many factors contribute to successful perception of auditory stimuli in noise, including neural encoding in the central auditory system. Physiological measures such as cortical auditory evoked potentials can provide a view of neural encoding at the level of the cortex that may inform our understanding of listeners’ abilities to perceive signals in the presence of background noise. In order to understand signal-in-noise neural encoding better, we set out to determine the effect of signal type, noise type, and evoking paradigm on the P1-N1-P2 complex. Design Tones and speech stimuli were presented to nine individuals in quiet, and in three background noise types: continuous speech spectrum noise, interrupted speech spectrum noise, and four-talker babble at a signal-to-noise ratio of −3 dB. In separate sessions, cortical auditory evoked potentials were evoked by a passive homogenous paradigm (single repeating stimulus) and an active oddball paradigm. Results The results for the N1 component indicated significant effects of signal type, noise type, and evoking paradigm. While components P1 and P2 also had significant main effects of these variables, only P2 demonstrated significant interactions among these variables. Conclusions Signal type, noise type, and evoking paradigm all must be carefully considered when interpreting signal-in-noise evoked potentials. Furthermore, these data confirm the possible usefulness of CAEPs as an aid to understanding perception-in-noise deficits. PMID:20890206

Improving Focal Depth Estimates: Studies of Depth Phase Detection at Regional Distances

Science.gov (United States)

Stroujkova, A.; Reiter, D. T.; Shumway, R. H.

2006-12-01

The accurate estimation of the depth of small, regionally recorded events continues to be an important and difficult explosion monitoring research problem. Depth phases (free surface reflections) are the primary tool that seismologists use to constrain the depth of a seismic event. When depth phases from an event are detected, an accurate source depth is easily found by using the delay times of the depth phases relative to the P wave and a velocity profile near the source. Cepstral techniques, including cepstral F-statistics, represent a class of methods designed for the depth-phase detection and identification; however, they offer only a moderate level of success at epicentral distances less than 15°. This is due to complexities in the Pn coda, which can lead to numerous false detections in addition to the true phase detection. Therefore, cepstral methods cannot be used independently to reliably identify depth phases. Other evidence, such as apparent velocities, amplitudes and frequency content, must be used to confirm whether the phase is truly a depth phase. In this study we used a variety of array methods to estimate apparent phase velocities and arrival azimuths, including beam-forming, semblance analysis, MUltiple SIgnal Classification (MUSIC) (e.g., Schmidt, 1979), and cross-correlation (e.g., Cansi, 1995; Tibuleac and Herrin, 1997). To facilitate the processing and comparison of results, we developed a MATLAB-based processing tool, which allows application of all of these techniques (i.e., augmented cepstral processing) in a single environment. The main objective of this research was to combine the results of three focal-depth estimation techniques and their associated standard errors into a statistically valid unified depth estimate. The three techniques include: 1. Direct focal depth estimate from the depth-phase arrival times picked via augmented cepstral processing. 2. Hypocenter location from direct and surface-reflected arrivals observed on sparse

Sputtering as a means of depth profiling

International Nuclear Information System (INIS)

Whitton, J.L.

1978-01-01

Probably the most common technique for determination of depth profiles by sputtering is that of secondary ion mass spectrometry. Many problems occur in the important step of converting the time (of sputtering) scale to a depth scale and these problems arise before the secondary ions are ejected. An attempt is made to present a comprehensive list of the effects that should be taken into consideration in the use of sputtering as a means of depth profiling. The various parameters liable to affect the depth profile measurements are listed in four sections: beam conditions; target conditions; experimental environment; and beam-target interactions. The effects are discussed and where interplay occurs, cross-reference is made and examples are provided where possible. (B.R.H.)

Minimal-memory realization of pearl-necklace encoders of general quantum convolutional codes

International Nuclear Information System (INIS)

Houshmand, Monireh; Hosseini-Khayat, Saied

2011-01-01

Quantum convolutional codes, like their classical counterparts, promise to offer higher error correction performance than block codes of equivalent encoding complexity, and are expected to find important applications in reliable quantum communication where a continuous stream of qubits is transmitted. Grassl and Roetteler devised an algorithm to encode a quantum convolutional code with a ''pearl-necklace'' encoder. Despite their algorithm's theoretical significance as a neat way of representing quantum convolutional codes, it is not well suited to practical realization. In fact, there is no straightforward way to implement any given pearl-necklace structure. This paper closes the gap between theoretical representation and practical implementation. In our previous work, we presented an efficient algorithm to find a minimal-memory realization of a pearl-necklace encoder for Calderbank-Shor-Steane (CSS) convolutional codes. This work is an extension of our previous work and presents an algorithm for turning a pearl-necklace encoder for a general (non-CSS) quantum convolutional code into a realizable quantum convolutional encoder. We show that a minimal-memory realization depends on the commutativity relations between the gate strings in the pearl-necklace encoder. We find a realization by means of a weighted graph which details the noncommutative paths through the pearl necklace. The weight of the longest path in this graph is equal to the minimal amount of memory needed to implement the encoder. The algorithm has a polynomial-time complexity in the number of gate strings in the pearl-necklace encoder.

Distributed multi-hypothesis coding of depth maps using texture motion information and optical flow

DEFF Research Database (Denmark)

Salmistraro, Matteo; Zamarin, Marco; Rakêt, Lars Lau

2013-01-01

Distributed Video Coding (DVC) is a video coding paradigm allowing a shift of complexity from the encoder to the decoder. Depth maps are images enabling the calculation of the distance of an object from the camera, which can be used in multiview coding in order to generate virtual views, but also...

ERP Correlates of Encoding Success and Encoding Selectivity in Attention Switching

Science.gov (United States)

Yeung, Nick

2016-01-01

Long-term memory encoding depends critically on effective processing of incoming information. The degree to which participants engage in effective encoding can be indexed in electroencephalographic (EEG) data by studying event-related potential (ERP) subsequent memory effects. The current study investigated ERP correlates of memory success operationalised with two different measures—memory selectivity and global memory—to assess whether previously observed ERP subsequent memory effects reflect focused encoding of task-relevant information (memory selectivity), general encoding success (global memory), or both. Building on previous work, the present study combined an attention switching paradigm—in which participants were presented with compound object-word stimuli and switched between attending to the object or the word across trials—with a later recognition memory test for those stimuli, while recording their EEG. Our results provided clear evidence that subsequent memory effects resulted from selective attentional focusing and effective top-down control (memory selectivity) in contrast to more general encoding success effects (global memory). Further analyses addressed the question of whether successful encoding depended on similar control mechanisms to those involved in attention switching. Interestingly, differences in the ERP correlates of attention switching and successful encoding, particularly during the poststimulus period, indicated that variability in encoding success occurred independently of prestimulus demands for top-down cognitive control. These results suggest that while effects of selective attention and selective encoding co-occur behaviourally their ERP correlates are at least partly dissociable. PMID:27907075

Alpha-crystallins are involved in specific interactions with the murine gamma D/E/F-crystallin-encoding gene.

Science.gov (United States)

Pietrowski, D; Durante, M J; Liebstein, A; Schmitt-John, T; Werner, T; Graw, J

1994-07-08

The promoter of the murine gamma E-crystallin (gamma E-Cry) encoding gene (gamma E-cry) was analyzed for specific interactions with lenticular proteins in a gel-retardation assay. A 21-bp fragment immediately downstream of the transcription initiation site (DOTIS) is demonstrated to be responsible for specific interactions with lens extracts. The DOTIS-binding protein(s) accept only the sense DNA strand as target; anti-sense or double-stranded DNA do not interact with these proteins. The DOTIS sequence element is highly conserved among the murine gamma D-, gamma E- and gamma F-cry and is present at comparable positions in the orthologous rat genes. Only a weak or even no protein-binding activity is observed if a few particular bases are changed, as in the rat gamma A-, gamma C- and gamma E-cry elements. DOTIS-binding proteins were found in commercially available bovine alpha-Cry preparations. The essential participation of alpha-Cry in the DNA-binding protein complex was confirmed using alpha-Cry-specific monoclonal antibody. The results reported here point to a novel function of alpha-Cry besides the structural properties in the lens.

Power calculation of linear and angular incremental encoders

Science.gov (United States)

Prokofev, Aleksandr V.; Timofeev, Aleksandr N.; Mednikov, Sergey V.; Sycheva, Elena A.

2016-04-01

Automation technology is constantly expanding its role in improving the efficiency of manufacturing and testing processes in all branches of industry. More than ever before, the mechanical movements of linear slides, rotary tables, robot arms, actuators, etc. are numerically controlled. Linear and angular incremental photoelectric encoders measure mechanical motion and transmit the measured values back to the control unit. The capabilities of these systems are undergoing continual development in terms of their resolution, accuracy and reliability, their measuring ranges, and maximum speeds. This article discusses the method of power calculation of linear and angular incremental photoelectric encoders, to find the optimum parameters for its components, such as light emitters, photo-detectors, linear and angular scales, optical components etc. It analyzes methods and devices that permit high resolutions in the order of 0.001 mm or 0.001°, as well as large measuring lengths of over 100 mm. In linear and angular incremental photoelectric encoders optical beam is usually formulated by a condenser lens passes through the measuring unit changes its value depending on the movement of a scanning head or measuring raster. Past light beam is converting into an electrical signal by the photo-detecter's block for processing in the electrical block. Therefore, for calculating the energy source is a value of the desired value of the optical signal at the input of the photo-detecter's block, which reliably recorded and processed in the electronic unit of linear and angular incremental optoelectronic encoders. Automation technology is constantly expanding its role in improving the efficiency of manufacturing and testing processes in all branches of industry. More than ever before, the mechanical movements of linear slides, rotary tables, robot arms, actuators, etc. are numerically controlled. Linear and angular incremental photoelectric encoders measure mechanical motion and

Proteins Encoded in Genomic Regions Associated with Immune-Mediated Disease Physically Interact and Suggest Underlying Biology

DEFF Research Database (Denmark)

Rossin, Elizabeth J.; Hansen, Kasper Lage; Raychaudhuri, Soumya

2011-01-01

Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed by these r......Genome-wide association studies (GWAS) have defined over 150 genomic regions unequivocally containing variation predisposing to immune-mediated disease. Inferring disease biology from these observations, however, hinges on our ability to discover the molecular processes being perturbed...... in rheumatoid arthritis (RA) and Crohn's disease (CD) GWAS, we build protein-protein interaction (PPI) networks for genes within associated loci and find abundant physical interactions between protein products of associated genes. We apply multiple permutation approaches to show that these networks are more...... that the RA and CD networks have predictive power by demonstrating that proteins in these networks, not encoded in the confirmed list of disease associated loci, are significantly enriched for association to the phenotypes in question in extended GWAS analysis. Finally, we test our method in 3 non...

Hydrologic controls on the development of equilibrium soil depths

Science.gov (United States)

Nicotina, L.; Tarboton, D. G.; Tesfa, T. K.; Rinaldo, A.

2010-12-01

The object of the present work was the study of the coevolution of runoff production and geomorphological processes and its effects on the formation of equilibrium soil depth by focusing on their mutual feedbacks. The primary goal of this work is to describe spatial patterns of soil depth resulting, under the hypothesis of dynamic equilibrium, from long-term interactions between hydrologic forcings and soil production, erosion and sediment transport processes. These processes dominate the formation of actual soil depth patterns that represent the boundary condition for water redistribution, thus this paper also proposes and attempt to set the premises for decoding their individual role and mutual interactions in shaping the hydrologic response of a catchment. The relevance of the study stems from the massive improvement in hydrologic predictions for ungauged basins that would be achieved by using directly soil depths derived from geomorphic features remotely measured and objectively manipulated. Moreover the setup of a coupled hydrologic-geomorphologic approach represents a first step into the study of such interactions and in particular of the effects of soil moisture in determining soil production functions. Hydrological processes are here described by explicitly accounting for local soil depths and detailed catchment topography from high resolution digital terrain models (DTM). Geomorphological processes are described by means of well-studied geomorphic transport laws. Soil depth is assumed, in the exponential soil production function, as a proxy for all the mechanisms that induce mechanical disruption of bedrock and it’s conversion into soil. This formulation, although empirical, has been widely used in the literature and is currently accepted. The modeling approach is applied to the semi-arid Dry Creek Experimental Watershed, located near Boise, Idaho, USA. Modeled soil depths are compared with field data obtained from an extensive survey of the catchment

Human action recognition with depth cameras

CERN Document Server

Wang, Jiang; Wu, Ying

2014-01-01

Action recognition technology has many real-world applications in human-computer interaction, surveillance, video retrieval, retirement home monitoring, and robotics. The commoditization of depth sensors has also opened up further applications that were not feasible before. This text focuses on feature representation and machine learning algorithms for action recognition from depth sensors. After presenting a comprehensive overview of the state of the art, the authors then provide in-depth descriptions of their recently developed feature representations and machine learning techniques, includi

Engineering non-linear resonator mode interactions in circuit QED by continuous driving: Manipulation of a photonic quantum memory

Science.gov (United States)

Reagor, Matthew; Pfaff, Wolfgang; Heeres, Reinier; Ofek, Nissim; Chou, Kevin; Blumoff, Jacob; Leghtas, Zaki; Touzard, Steven; Sliwa, Katrina; Holland, Eric; Albert, Victor V.; Frunzio, Luigi; Devoret, Michel H.; Jiang, Liang; Schoelkopf, Robert J.

2015-03-01

Recent advances in circuit QED have shown great potential for using microwave resonators as quantum memories. In particular, it is possible to encode the state of a quantum bit in non-classical photonic states inside a high-Q linear resonator. An outstanding challenge is to perform controlled operations on such a photonic state. We demonstrate experimentally how a continuous drive on a transmon qubit coupled to a high-Q storage resonator can be used to induce non-linear dynamics of the resonator. Tailoring the drive properties allows us to cancel or enhance non-linearities in the system such that we can manipulate the state stored in the cavity. This approach can be used to either counteract undesirable evolution due to the bare Hamiltonian of the system or, ultimately, to perform logical operations on the state encoded in the cavity field. Our method provides a promising pathway towards performing universal control for quantum states stored in high-coherence resonators in the circuit QED platform.

Profilometric characterization of DOEs with continuous microrelief

Science.gov (United States)

Korolkov, V. P.; Ostapenko, S. V.; Shimansky, R. V.

2008-09-01

Methodology of local characterization of continuous-relief diffractive optical elements has been discussed. The local profile depth can be evaluated using "approximated depth" defined without taking a profile near diffractive zone boundaries into account. Several methods to estimate the approximated depth have been offered.

Encoding the world around us: motor-related processing influences verbal memory.

Science.gov (United States)

Madan, Christopher R; Singhal, Anthony

2012-09-01

It is known that properties of words such as their imageability can influence our ability to remember those words. However, it is not known if other object-related properties can also influence our memory. In this study we asked whether a word representing a concrete object that can be functionally interacted with (i.e., high-manipulability word) would enhance the memory representations for that item compared to a word representing a less manipulable object (i.e., low-manipulability word). Here participants incidentally encoded high-manipulability (e.g., CAMERA) and low-manipulability words (e.g., TABLE) while making word judgments. Using a between-subjects design, we varied the depth-of-processing involved in the word judgment task: participants judged the words based on personal experience (deep/elaborative processing), word length (shallow), or functionality (intermediate). Participants were able to remember high-manipulability words better than low-manipulability words in both the personal experience and word length groups; thus presenting the first evidence that manipulability can influence memory. However, we observed better memory for low- than high-manipulability words in the functionality group. We explain this surprising interaction between manipulability and memory as being mediated by automatic vs. controlled motor-related cognition. Copyright © 2012 Elsevier Inc. All rights reserved.

SnoVault and encodeD: A novel object-based storage system and applications to ENCODE metadata.

Directory of Open Access Journals (Sweden)

Benjamin C Hitz

Full Text Available The Encyclopedia of DNA elements (ENCODE project is an ongoing collaborative effort to create a comprehensive catalog of functional elements initiated shortly after the completion of the Human Genome Project. The current database exceeds 6500 experiments across more than 450 cell lines and tissues using a wide array of experimental techniques to study the chromatin structure, regulatory and transcriptional landscape of the H. sapiens and M. musculus genomes. All ENCODE experimental data, metadata, and associated computational analyses are submitted to the ENCODE Data Coordination Center (DCC for validation, tracking, storage, unified processing, and distribution to community resources and the scientific community. As the volume of data increases, the identification and organization of experimental details becomes increasingly intricate and demands careful curation. The ENCODE DCC has created a general purpose software system, known as SnoVault, that supports metadata and file submission, a database used for metadata storage, web pages for displaying the metadata and a robust API for querying the metadata. The software is fully open-source, code and installation instructions can be found at: http://github.com/ENCODE-DCC/snovault/ (for the generic database and http://github.com/ENCODE-DCC/encoded/ to store genomic data in the manner of ENCODE. The core database engine, SnoVault (which is completely independent of ENCODE, genomic data, or bioinformatic data has been released as a separate Python package.

Continuous-variable quantum information processing

DEFF Research Database (Denmark)

Andersen, Ulrik Lund; Leuchs, G.; Silberhorn, C.

2010-01-01

the continuous degree of freedom of a quantum system for encoding, processing or detecting information, one enters the field of continuous-variable (CV) quantum information processing. In this paper we review the basic principles of CV quantum information processing with main focus on recent developments...... in the field. We will be addressing the three main stages of a quantum information system; the preparation stage where quantum information is encoded into CVs of coherent states and single-photon states, the processing stage where CV information is manipulated to carry out a specified protocol and a detection...... stage where CV information is measured using homodyne detection or photon counting....

Reconstruction in PET cameras with irregular sampling and depth of interaction capability

International Nuclear Information System (INIS)

Virador, P.R.G.; Moses, W.W.; Huesman, R.H.

1998-01-01

The authors present 2D reconstruction algorithms for a rectangular PET camera capable of measuring depth of interaction (DOI). The camera geometry leads to irregular radial and angular sampling of the tomographic data. DOI information increases sampling density, allowing the use of evenly spaced quarter-crystal width radial bins with minimal interpolation of irregularly spaced data. In the regions where DOI does not increase sampling density (chords normal to crystal faces), fine radial sinogram binning leads to zero efficiency bins if uniform angular binning is used. These zero efficiency sinogram bins lead to streak artifacts if not corrected. To minimize these unnormalizable sinogram bins the authors use two angular binning schemes: Fixed Width and Natural Width. Fixed Width uses a fixed angular width except in the problem regions where appropriately chosen widths are applied. Natural Width uses angle widths which are derived from intrinsic detector sampling. Using a modified filtered-backprojection algorithm to accommodate these angular binning schemes, the authors reconstruct artifact free images with nearly isotropic and position independent spatial resolution. Results from Monte Carlo data indicate that they have nearly eliminated image degradation due to crystal penetration

Distributed-phase OCDMA encoder-decoders based on fiber Bragg gratings

OpenAIRE

Zhang, Zhaowei; Tian, C.; Petropoulos, P.; Richardson, D.J.; Ibsen, M.

2007-01-01

We propose and demonstrate new optical code-division multiple-access (OCDMA) encoder-decoders having a continuous phase-distribution. With the same spatial refractive index distribution as the reconfigurable optical phase encoder-decoders, they are inherently suitable for the application in reconfigurable OCDMA systems. Furthermore, compared with conventional discrete-phase devices, they also have additional advantages of being more tolerant to input pulse width and, therefore, have the poten...

Defocus Deblurring and Superresolution for Time-of-Flight Depth Cameras

KAUST Repository

Xiao, Lei

2015-06-07

Continuous-wave time-of-flight (ToF) cameras show great promise as low-cost depth image sensors in mobile applications. However, they also suffer from several challenges, including limited illumination intensity, which mandates the use of large numerical aperture lenses, and thus results in a shallow depth of field, making it difficult to capture scenes with large variations in depth. Another shortcoming is the limited spatial resolution of currently available ToF sensors. In this paper we analyze the image formation model for blurred ToF images. By directly working with raw sensor measurements but regularizing the recovered depth and amplitude images, we are able to simultaneously deblur and super-resolve the output of ToF cameras. Our method outperforms existing methods on both synthetic and real datasets. In the future our algorithm should extend easily to cameras that do not follow the cosine model of continuous-wave sensors, as well as to multi-frequency or multi-phase imaging employed in more recent ToF cameras.

Defocus Deblurring and Superresolution for Time-of-Flight Depth Cameras

KAUST Repository

Xiao, Lei; Heide, Felix; O'Toole, Matthew; Kolb, Andreas; Hullin, Matthias B.; Kutulakos, Kyros; Heidrich, Wolfgang

2015-01-01

Continuous-wave time-of-flight (ToF) cameras show great promise as low-cost depth image sensors in mobile applications. However, they also suffer from several challenges, including limited illumination intensity, which mandates the use of large numerical aperture lenses, and thus results in a shallow depth of field, making it difficult to capture scenes with large variations in depth. Another shortcoming is the limited spatial resolution of currently available ToF sensors. In this paper we analyze the image formation model for blurred ToF images. By directly working with raw sensor measurements but regularizing the recovered depth and amplitude images, we are able to simultaneously deblur and super-resolve the output of ToF cameras. Our method outperforms existing methods on both synthetic and real datasets. In the future our algorithm should extend easily to cameras that do not follow the cosine model of continuous-wave sensors, as well as to multi-frequency or multi-phase imaging employed in more recent ToF cameras.

Changes in the modulation of brain activity during context encoding vs. context retrieval across the adult lifespan.

Science.gov (United States)

Ankudowich, E; Pasvanis, S; Rajah, M N

2016-10-01

Age-related deficits in context memory may arise from neural changes underlying both encoding and retrieval of context information. Although age-related functional changes in the brain regions supporting context memory begin at midlife, little is known about the functional changes with age that support context memory encoding and retrieval across the adult lifespan. We investigated how age-related functional changes support context memory across the adult lifespan by assessing linear changes with age during successful context encoding and retrieval. Using functional magnetic resonance imaging (fMRI), we compared young, middle-aged and older adults during both encoding and retrieval of spatial and temporal details of faces. Multivariate behavioral partial least squares (B-PLS) analysis of fMRI data identified a pattern of whole-brain activity that correlated with a linear age term and a pattern of whole-brain activity that was associated with an age-by-memory phase (encoding vs. retrieval) interaction. Further investigation of this latter effect identified three main findings: 1) reduced phase-related modulation in bilateral fusiform gyrus, left superior/anterior frontal gyrus and right inferior frontal gyrus that started at midlife and continued to older age, 2) reduced phase-related modulation in bilateral inferior parietal lobule that occurred only in older age, and 3) changes in phase-related modulation in older but not younger adults in left middle frontal gyrus and bilateral parahippocampal gyrus that was indicative of age-related over-recruitment. We conclude that age-related reductions in context memory arise in midlife and are related to changes in perceptual recollection and changes in fronto-parietal retrieval monitoring. Crown Copyright © 2016. Published by Elsevier Inc. All rights reserved.

Soil depth influence on Amazonian ecophysiology

Science.gov (United States)

Fagerstrom, I.; Baker, I. T.; Gallup, S.; Denning, A. S.

2017-12-01

Models of land-atmosphere interaction are important for simulating present day weather and critical for predictions of future climate. Land-atmosphere interaction models have become increasingly complex in the last 30 years, leading to the need for further studies examining their intricacies and improvement. This research focuses on the effect of variable soil depth on Amazonian Gross Primary Production (GPP), respiration, and their combination into overall carbon flux. We evaluate a control, which has a universal soil depth of 10 meters, with two experiments of variable soil depths. To conduct this study we ran the 3 models for the period 2000-2012, evaluating similarities and differences between them. We focus on the Amazon rain forest, and compare differences in components of carbon flux. Not surprisingly, we find that the main differences between the models arises in regions where the soil depth is dissimilar between models. However, we did not observe significant differences in GPP between known drought, wet, and average years; interannual variability in carbon dynamics was less than anticipated. We also anticipated that differences between models would be most significant during the dry season, but found discrepancies that persisted through the entire annual cycle.

An analysis of depth dose characteristics of photon in water

International Nuclear Information System (INIS)

Buzdar, S.A.; Rao, M.A.; Nazir, A.

2009-01-01

Photon beam is most widely being used for radiation therapy. Biological effect of radiation is concerned with the evaluation of energy absorbed in the tissues. It was aimed to analyse the depth dose characteristics of x-ray beams of diverse energies to enhance the quality of radiotherapy treatment planning. Depth dose characteristics of different energy photon beams in water have been analysed. Photon beam is attenuated by the medium and the transmitted beam with less intensity causes lesser absorbed dose as depth increases. Relative attenuation on certain points on the beam axis and certain percentage of doses on different depths for available energies has been investigated. Photon beam depth dose characteristics do not show identical attributes as interaction of x-ray with matter is mainly governed by beam quality. Attenuation and penetration parameters of photon show variation with dosimetric parameters like field size due to scattering and Source to Surface Distance due to inverse square law, but the major parameter in photon interactions is its energy. Detailed analysis of photon Depth Dose characteristics helps to select appropriate beam for radiotherapy treatment when variety of beam energies available. Evaluation of this type of characteristics will help to establish theoretical relationships between dosimetric parameters to confirm measured values of dosimetric quantities, and hence to increase accuracy in radiotherapy treatment. (author)

Effect of phase-encoding direction on group analysis of resting-state functional magnetic resonance imaging.

Science.gov (United States)

Mori, Yasuo; Miyata, Jun; Isobe, Masanori; Son, Shuraku; Yoshihara, Yujiro; Aso, Toshihiko; Kouchiyama, Takanori; Murai, Toshiya; Takahashi, Hidehiko

2018-05-17

Echo-planar imaging is a common technique used in functional magnetic resonance imaging (fMRI), however it suffers from image distortion and signal loss because of large susceptibility effects that are related to the phase-encoding direction of the scan. Despite this relationship, the majority of neuroimaging studies have not considered the influence of phase-encoding direction. Here, we aimed to clarify how phase-encoding direction can affect the outcome of an fMRI connectivity study of schizophrenia. Resting-state fMRI using anterior to posterior (A-P) and posterior to anterior (P-A) directions was used to examine 25 patients with schizophrenia (SC) and 37 matched healthy controls (HC). We conducted a functional connectivity analysis using independent component analysis and performed three group comparisons: A-P vs. P-A (all participants), SC vs. HC for the A-P and P-A datasets, and the interaction between phase-encoding direction and participant group. The estimated functional connectivity differed between the two phase-encoding directions in areas that were more extensive than those where signal loss has been reported. Although functional connectivity in the SC group was lower than that in the HC group for both directions, the A-P and P-A conditions did not exhibit the same specific pattern of differences. Further, we observed an interaction between participant group and the phase-encoding direction in the left temporo-parietal junction and left fusiform gyrus. Phase-encoding direction can influence the results of functional connectivity studies. Thus, appropriate selection and documentation of phase-encoding direction will be important in future resting-state fMRI studies. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Lab-on-a-chip platform for high throughput drug discovery with DNA-encoded chemical libraries

Science.gov (United States)

Grünzner, S.; Reddavide, F. V.; Steinfelder, C.; Cui, M.; Busek, M.; Klotzbach, U.; Zhang, Y.; Sonntag, F.

2017-02-01

The fast development of DNA-encoded chemical libraries (DECL) in the past 10 years has received great attention from pharmaceutical industries. It applies the selection approach for small molecular drug discovery. Because of the limited choices of DNA-compatible chemical reactions, most DNA-encoded chemical libraries have a narrow structural diversity and low synthetic yield. There is also a poor correlation between the ranking of compounds resulted from analyzing the sequencing data and the affinity measured through biochemical assays. By combining DECL with dynamical chemical library, the resulting DNA-encoded dynamic library (EDCCL) explores the thermodynamic equilibrium of reversible reactions as well as the advantages of DNA encoded compounds for manipulation/detection, thus leads to enhanced signal-to-noise ratio of the selection process and higher library quality. However, the library dynamics are caused by the weak interactions between the DNA strands, which also result in relatively low affinity of the bidentate interaction, as compared to a stable DNA duplex. To take advantage of both stably assembled dual-pharmacophore libraries and EDCCLs, we extended the concept of EDCCLs to heat-induced EDCCLs (hi-EDCCLs), in which the heat-induced recombination process of stable DNA duplexes and affinity capture are carried out separately. To replace the extremely laborious and repetitive manual process, a fully automated device will facilitate the use of DECL in drug discovery. Herein we describe a novel lab-on-a-chip platform for high throughput drug discovery with hi-EDCCL. A microfluidic system with integrated actuation was designed which is able to provide a continuous sample circulation by reducing the volume to a minimum. It consists of a cooled and a heated chamber for constant circulation. The system is capable to generate stable temperatures above 75 °C in the heated chamber to melt the double strands of the DNA and less than 15 °C in the cooled chamber

Spatio-Temporal Encoding in Medical Ultrasound Imaging

DEFF Research Database (Denmark)

Gran, Fredrik

2005-01-01

In this dissertation two methods for spatio-temporal encoding in medical ultrasound imaging are investigated. The first technique is based on a frequency division approach. Here, the available spectrum of the transducer is divided into a set of narrow bands. A waveform is designed for each band...... the signal to noise ratio and simultaneously the penetration depth so that the medical doctor can image deeper lying structures. The method is tested both experimentally and in simulation and has also evaluated for the purpose of blood flow estimation. The work presented is based on four papers which...

The new INRIM rotating encoder angle comparator (REAC)

International Nuclear Information System (INIS)

Pisani, Marco; Astrua, Milena

2017-01-01

A novel angle comparator has been built and tested at INRIM. The device is based on a double air bearing structure embedding a continuously rotating encoder, which is read by two heads: one fixed to the base of the comparator and a second fixed to the upper moving part of the comparator. The phase measurement between the two heads’ signals is proportional to the relative angle suspended between them (and, therefore, the angle between the base and the upper, movable part of the comparator). The advantage of this solution is to reduce the encoder graduation errors and to cancel the cyclic errors due to the interpolation of the encoder lines. By using only two pairs of reading heads, we have achieved an intrinsic accuracy of  ±0.04″ (rectangular distribution) that can be reduced through self-calibration. The residual cyclic errors have shown to be less than 0.01″ peak-to-peak. The random fluctuations are less than 0.01″ rms on a 100 s time interval. A further advantage of the rotating encoder is the intrinsic knowledge of the absolute position without the need of a zeroing procedure. Construction details of the rotating encoder angle comparator (REAC), characterization tests, and examples of practical use are given. (paper)

Novel Intermode Prediction Algorithm for High Efficiency Video Coding Encoder

Directory of Open Access Journals (Sweden)

Chan-seob Park

2014-01-01

Full Text Available The joint collaborative team on video coding (JCT-VC is developing the next-generation video coding standard which is called high efficiency video coding (HEVC. In the HEVC, there are three units in block structure: coding unit (CU, prediction unit (PU, and transform unit (TU. The CU is the basic unit of region splitting like macroblock (MB. Each CU performs recursive splitting into four blocks with equal size, starting from the tree block. In this paper, we propose a fast CU depth decision algorithm for HEVC technology to reduce its computational complexity. In 2N×2N PU, the proposed method compares the rate-distortion (RD cost and determines the depth using the compared information. Moreover, in order to speed up the encoding time, the efficient merge SKIP detection method is developed additionally based on the contextual mode information of neighboring CUs. Experimental result shows that the proposed algorithm achieves the average time-saving factor of 44.84% in the random access (RA at Main profile configuration with the HEVC test model (HM 10.0 reference software. Compared to HM 10.0 encoder, a small BD-bitrate loss of 0.17% is also observed without significant loss of image quality.

a permutation encoding te algorithm solution of reso tation encoding

African Journals Online (AJOL)

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Keywords: Genetic algorithm, resource constrained. 1. INTRODUCTION. 1. .... Nigerian Journal of Technology. Vol. 34, No. 1, January 2015. 128 ... 4. ENCODING OF CHROMOSOME. ENCODING OF CHROMOSOME .... International Multi conference of Engineers and ... method”, Naval Research Logistics, vol 48, issue 2,.

Depth Value Pre-Processing for Accurate Transfer Learning Based RGB-D Object Recognition

DEFF Research Database (Denmark)

Aakerberg, Andreas; Nasrollahi, Kamal; Rasmussen, Christoffer Bøgelund

2017-01-01

of an existing deeplearning based RGB-D object recognition model, namely the FusionNet proposed by Eitel et al. First, we showthat encoding the depth values as colorized surface normals is beneficial, when the model is initialized withweights learned from training on ImageNet data. Additionally, we show...

Hardness depth profiling of case hardened steels using a three-dimensional photothermal technique

International Nuclear Information System (INIS)

Qu Hong; Wang Chinhua; Guo Xinxin; Mandelis, Andreas

2010-01-01

A method of retrieving thermophysical depth profiles of continuously inhomogeneous materials is presented both theoretically and experimentally using the three-dimensional (3-D) photothermal radiometry. A 3-D theoretical model suitable for characterizing solids with arbitrary continuously varying thermophysical property depth profiles and finite (collimated or focused) laser beam spotsize is developed. A numerical fitting algorithm to retrieve the thermophysical profile was demonstrated with three case hardened steel samples. The reconstructed thermal conductivity depth profiles were found to be well anti-correlated with microhardness profiles obtained with the conventional indenter method.

Quantum key distribution using basis encoding of Gaussian-modulated coherent states

Science.gov (United States)

Huang, Peng; Huang, Jingzheng; Zhang, Zheshen; Zeng, Guihua

2018-04-01

The continuous-variable quantum key distribution (CVQKD) has been demonstrated to be available in practical secure quantum cryptography. However, its performance is restricted strongly by the channel excess noise and the reconciliation efficiency. In this paper, we present a quantum key distribution (QKD) protocol by encoding the secret keys on the random choices of two measurement bases: the conjugate quadratures X and P . The employed encoding method can dramatically weaken the effects of channel excess noise and reconciliation efficiency on the performance of the QKD protocol. Subsequently, the proposed scheme exhibits the capability to tolerate much higher excess noise and enables us to reach a much longer secure transmission distance even at lower reconciliation efficiency. The proposal can work alternatively to strengthen significantly the performance of the known Gaussian-modulated CVQKD protocol and serve as a multiplier for practical secure quantum cryptography with continuous variables.

Molecular and functional interactions of cat APOBEC3 and feline foamy and immunodeficiency virus proteins: different ways to counteract host-encoded restriction.

Science.gov (United States)

Chareza, Sarah; Slavkovic Lukic, Dragana; Liu, Yang; Räthe, Ann-Mareen; Münk, Carsten; Zabogli, Elisa; Pistello, Mauro; Löchelt, Martin

2012-03-15

Defined host-encoded feline APOBEC3 (feA3) cytidine deaminases efficiently restrict the replication and spread of exogenous retroviruses like Feline Immunodeficiency Virus (FIV) and Feline Foamy Virus (FFV) which developed different feA3 counter-acting strategies. Here we characterize the molecular interaction of FFV proteins with the diverse feA3 proteins. The FFV accessory protein Bet is the virus-encoded defense factor which is shown here to bind all feA3 proteins independent of whether they restrict FFV, a feature shared with FIV Vif that induces degradation of all feA3s including those that do not inactivate FIV. In contrast, only some feA3 proteins bind to FFV Gag, a pattern that in part reflects the restriction pattern detected. Additionally, one-domain feA3 proteins can homo- and hetero-dimerize in vitro, but a trans-dominant phenotype of any of the low-activity feA3 forms on FFV restriction by one of the highly-active feA3Z2 proteins was not detectable. Copyright © 2012 Elsevier Inc. All rights reserved.

Kinect Fusion improvement using depth camera calibration

Science.gov (United States)

Pagliari, D.; Menna, F.; Roncella, R.; Remondino, F.; Pinto, L.

2014-06-01

Scene's 3D modelling, gesture recognition and motion tracking are fields in rapid and continuous development which have caused growing demand on interactivity in video-game and e-entertainment market. Starting from the idea of creating a sensor that allows users to play without having to hold any remote controller, the Microsoft Kinect device was created. The Kinect has always attract researchers in different fields, from robotics to Computer Vision (CV) and biomedical engineering as well as third-party communities that have released several Software Development Kit (SDK) versions for Kinect in order to use it not only as a game device but as measurement system. Microsoft Kinect Fusion control libraries (firstly released in March 2013) allow using the device as a 3D scanning and produce meshed polygonal of a static scene just moving the Kinect around. A drawback of this sensor is the geometric quality of the delivered data and the low repeatability. For this reason the authors carried out some investigation in order to evaluate the accuracy and repeatability of the depth measured delivered by the Kinect. The paper will present a throughout calibration analysis of the Kinect imaging sensor, with the aim of establishing the accuracy and precision of the delivered information: a straightforward calibration of the depth sensor in presented and then the 3D data are correct accordingly. Integrating the depth correction algorithm and correcting the IR camera interior and exterior orientation parameters, the Fusion Libraries are corrected and a new reconstruction software is created to produce more accurate models.

Kinect Fusion improvement using depth camera calibration

Directory of Open Access Journals (Sweden)

D. Pagliari

2014-06-01

Full Text Available Scene's 3D modelling, gesture recognition and motion tracking are fields in rapid and continuous development which have caused growing demand on interactivity in video-game and e-entertainment market. Starting from the idea of creating a sensor that allows users to play without having to hold any remote controller, the Microsoft Kinect device was created. The Kinect has always attract researchers in different fields, from robotics to Computer Vision (CV and biomedical engineering as well as third-party communities that have released several Software Development Kit (SDK versions for Kinect in order to use it not only as a game device but as measurement system. Microsoft Kinect Fusion control libraries (firstly released in March 2013 allow using the device as a 3D scanning and produce meshed polygonal of a static scene just moving the Kinect around. A drawback of this sensor is the geometric quality of the delivered data and the low repeatability. For this reason the authors carried out some investigation in order to evaluate the accuracy and repeatability of the depth measured delivered by the Kinect. The paper will present a throughout calibration analysis of the Kinect imaging sensor, with the aim of establishing the accuracy and precision of the delivered information: a straightforward calibration of the depth sensor in presented and then the 3D data are correct accordingly. Integrating the depth correction algorithm and correcting the IR camera interior and exterior orientation parameters, the Fusion Libraries are corrected and a new reconstruction software is created to produce more accurate models.

Towards a map of the Populus biomass protein-protein interaction network

Energy Technology Data Exchange (ETDEWEB)

Beers, Eric [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Brunner, Amy [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Helm, Richard [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States); Dickerman, Allan [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

2015-07-31

Biofuels can be produced from a variety of plant feedstocks. The value of a particular feedstock for biofuels production depends in part on the degree of difficulty associated with the extraction of fermentable sugars from the plant biomass. The wood of trees is potentially a rich source fermentable sugars. However, the sugars in wood exist in a tightly cross-linked matrix of cellulose, hemicellulose, and lignin, making them largely recalcitrant to release and fermentation for biofuels production. Before breeders and genetic engineers can effectively develop plants with reduced recalcitrance to fermentation, it is necessary to gain a better understanding of the fundamental biology of the mechanisms responsible for wood formation. Regulatory, structural, and enzymatic proteins are required for the complicated process of wood formation. To function properly, proteins must interact with other proteins. Yet, very few of the protein-protein interactions necessary for wood formation are known. The main objectives of this project were to 1) identify new protein-protein interactions relevant to wood formation, and 2) perform in-depth characterizations of selected protein-protein interactions. To identify relevant protein-protein interactions, we cloned a set of approximately 400 genes that were highly expressed in the wood-forming tissue (known as secondary xylem) of poplar (Populus trichocarpa). We tested whether the proteins encoded by these biomass genes interacted with each other in a binary matrix design using the yeast two-hybrid (Y2H) method for protein-protein interaction discovery. We also tested a subset of the 400 biomass proteins for interactions with all proteins present in wood-forming tissue of poplar in a biomass library screen design using Y2H. Together, these two Y2H screens yielded over 270 interactions involving over 75 biomass proteins. For the second main objective we selected several interacting pairs or groups of interacting proteins for in-depth

Evaluation of algorithms for photon depth of interaction estimation for the TRIMAGE PET component

Energy Technology Data Exchange (ETDEWEB)

Camarlinghi, Niccolo; Belcari, Nicola [University of Pisa (Italy); Cerello, Piergiorgio [University of Torino (Italy); Sportelli, Giancarlo [University of Pisa (Italy); Pennazio, Francesco [University of Torino (Italy); Zaccario, Emanuele; Del Guerra, Alberto [University of Pisa (Italy)

2015-05-18

The TRIMAGE consortium aims to develop a multimodal PET/MR/EEG brain scanner dedicated to the early diagnosis of schizophrenia and other mental health disorders. The PET component features a full ring made of 18 detectors, each one consisting of twelve 8x8 Silicon PhotoMultipliers (SiPMs) tiles coupled to two segmented LYSO crystal matrices with staggered layers. In each module, the crystals belonging to the bottom layer are coupled one to one to the SiPMs, while each crystal of the top layer is coupled to four crystals of the bottom layer. This configuration allows to increase the crystal thickness while reducing the depth of interaction uncertainty, as photons interacting in different layers are expected to produce different light patterns on the SiPMs. The PET scanner will implement the pixel/layer identification on a front-end FPGA. This will allow increasing the effective bandwidth, setting at the same time restrictions on the complexity of the algorithms to be implemented. In this work two algorithms whose implementation is feasible directly on an FPGA are presented and evaluated. The first algorithm implements a method based on adaptive thresholding, while the other uses a linear Support Vector Machine (SVM) trained to distinguish the light pattern coming from two different layers. The validation of the algorithm performance is carried out by using simulated data generated with the GAMOS Monte Carlo. The obtained results show that the achieved accuracy in layer and pixel identification is above the 90% for both the proposed approaches.

Implementation of pencil kernel and depth penetration algorithms for treatment planning of proton beams

International Nuclear Information System (INIS)

Russell, K.R.; Saxner, M.; Ahnesjoe, A.; Montelius, A.; Grusell, E.; Dahlgren, C.V.

2000-01-01

The implementation of two algorithms for calculating dose distributions for radiation therapy treatment planning of intermediate energy proton beams is described. A pencil kernel algorithm and a depth penetration algorithm have been incorporated into a commercial three-dimensional treatment planning system (Helax-TMS, Helax AB, Sweden) to allow conformal planning techniques using irregularly shaped fields, proton range modulation, range modification and dose calculation for non-coplanar beams. The pencil kernel algorithm is developed from the Fermi-Eyges formalism and Moliere multiple-scattering theory with range straggling corrections applied. The depth penetration algorithm is based on the energy loss in the continuous slowing down approximation with simple correction factors applied to the beam penumbra region and has been implemented for fast, interactive treatment planning. Modelling of the effects of air gaps and range modifying device thickness and position are implicit to both algorithms. Measured and calculated dose values are compared for a therapeutic proton beam in both homogeneous and heterogeneous phantoms of varying complexity. Both algorithms model the beam penumbra as a function of depth in a homogeneous phantom with acceptable accuracy. Results show that the pencil kernel algorithm is required for modelling the dose perturbation effects from scattering in heterogeneous media. (author)

High-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip supports for AFP detection

Energy Technology Data Exchange (ETDEWEB)

Gong, Xiaoqun [School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin 300072 (China); Yan, Huan; Yang, Jiumin [Department of Laboratory Medicine, Tianjin Medical University General Hospital, Tianjin, 300052 (China); Wu, Yudong; Zhang, Jian; Yao, Yingyi [School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin 300072 (China); Liu, Ping [Bioscience (Tianjin) Diagnostic Technology CO., LTD, Tianjin, 300300 (China); Wang, Huiquan [Department of Biomedical Engineering, School of Electronics and Information Engineering, Tianjin Polytechnic University, Tianjin, 300387 (China); Hu, Zhidong, E-mail: huzhidong27@163.com [Department of Laboratory Medicine, Tianjin Medical University General Hospital, Tianjin, 300052 (China); Chang, Jin, E-mail: jinchang@tju.edu.cn [School of Life Sciences, Tianjin Engineering Center of Micro-Nano Biomaterials and Detection-Treatment Technology, Collaborative Innovation Center of Chemical Science and Engineering, Tianjin University, Tianjin 300072 (China)

2016-10-05

Fluorescence-encoded magnetic microbeads (FEMMs), with the fluorescence encoding ability of quantum dots (QDs) and magnetic enrichment and separation functions of Fe{sub 3}O{sub 4} nanoparticles, have been widely used for multiple biomolecular detection as microfluidic protein chip supports. However, the preparation of FEMMs with long-term fluorescent encoding and immunodetection stability is still a challenge. In this work, we designed a novel high-temperature chemical swelling strategy. The QDs and Fe{sub 3}O{sub 4} nanoparticles were effectively packaged into microbeads via the thermal motion of the polymer chains and the hydrophobic interaction between the nanoparticles and microbeads. The FEMMs obtained a highly uniform fluorescent property and long-term encoding and immunodetection stability and could be quickly magnetically separated and enriched. Then, the QD-encoded magnetic microbeads were applied to alpha fetoprotein (AFP) detection via sandwich immunoreaction. The properties of the encoded microspheres were characterized using a self-designed detecting apparatus, and the target molecular concentration in the sample was also quantified. The results suggested that the high-performance FEMMs have great potential in the field of biomolecular detection. - Graphical abstract: We designed a novel strategy to prepare a kind of high-performance fluorescence-encoded magnetic microbeads as microfluidic protein chip support with long-time fluorescent encoding and immunodetection stability for AFP detection. - Highlights: • A novel strategy combined the high temperature with chemical swelling technology is designed. • Based on hydrophobic interaction and polymer thermal motion, QDs and Fe{sub 3}O{sub 4} were effectively packaged into microbeads. • The fluorescence-encoded magnetic microbeads show long-term fluorescent encoding and immunodetection stability.

Reward modulation of hippocampal subfield activation during successful associative encoding and retrieval

Science.gov (United States)

Wolosin, Sasha M.; Zeithamova, Dagmar; Preston, Alison R.

2012-01-01

Emerging evidence suggests that motivation enhances episodic memory formation through interactions between medial temporal lobe (MTL) structures and dopaminergic midbrain. In addition, recent theories propose that motivation specifically facilitates hippocampal associative binding processes, resulting in more detailed memories that are readily reinstated from partial input. Here, we used high-resolution functional magnetic resonance imaging to determine how motivation influences associative encoding and retrieval processes within human MTL subregions and dopaminergic midbrain. Participants intentionally encoded object associations under varying conditions of reward and performed a retrieval task during which studied associations were cued from partial input. Behaviorally, cued recall performance was superior for high-value relative to low-value associations; however, participants differed in the degree to which rewards influenced memory. The magnitude of behavioral reward modulation was associated with reward-related activation changes in dentate gyrus/CA2,3 during encoding and enhanced functional connectivity between dentate gyrus/CA2,3 and dopaminergic midbrain during both the encoding and retrieval phases of the task. These findings suggests that within the hippocampus, reward-based motivation specifically enhances dentate gyrus/CA2,3 associative encoding mechanisms through interactions with dopaminergic midbrain. Furthermore, within parahippocampal cortex and dopaminergic midbrain regions, activation associated with successful memory formation was modulated by reward across the group. During the retrieval phase, we also observed enhanced activation in hippocampus and dopaminergic midbrain for high-value associations that occurred in the absence of any explicit cues to reward. Collectively, these findings shed light on fundamental mechanisms through which reward impacts associative memory formation and retrieval through facilitation of MTL and VTA/SN processing

Imaging Stress Transients and Fault Zone Processes with Crosswell Continuous Active-Source Seismic Monitoring at the San Andreas Fault Observatory at Depth

Science.gov (United States)

Niu, F.; Taira, T.; Daley, T. M.; Marchesini, P.; Robertson, M.; Wood, T.

2017-12-01

Recent field and laboratory experiments identify seismic velocity changes preceding microearthquakes and rock failure (Niu et al., 2008, Nature; Scuderi et al., 2016, NatureGeo), which indicates that a continuous monitoring of seismic velocity might provide a mean of understanding of the earthquake nucleation process. Crosswell Continuous Active-Source Seismic Monitoring (CASSM) using borehole sources and sensors has proven to be an effective tool for measurements of seismic velocity and its temporal variation at seismogenic depth (Silver, et al, 2007, BSSA; Daley, et al, 2007, Geophysics). To expand current efforts on the CASSM development, in June 2017 we have begun to conduct a year-long CASSM field experiment at the San Andreas Fault Observatory at Depth (SAFOD) in which the preceding field experiment detected the two sudden velocity reductions approximately 10 and 2 hours before microearthquakes (Niu et al., 2008, Nature). We installed a piezoelectric source and a three-component accelerometer at the SAFOD pilot and main holes ( 1 km depth) respectively. A seismic pulse was fired from the piezoelectric source four times per second. Each waveform was recorded 150-ms-long data with a sampling rate of 48 kHz. During this one-year experiment, we expect to have 10-15 microearthquakes (magnitude 1-3) occurring near the SAFOD site, and the data collected from the new experiment would allow us to further explore a relation between velocity changes and the Parkfield seismicity. Additionally, the year-long data provide a unique opportunity to study long-term velocity changes that might be related to seasonal stress variations at Parkfield (Johnson et al., 2017, Science). We will report on initial results of the SAFOD CASSM experiment and operational experiences of the CASSM development.

Recalled Aspects of Original Encoding Strategies Influence Episodic Feeling of Knowing

Science.gov (United States)

Hertzog, Christopher; Fulton, Erika K.; Sinclair, Starlette M.; Dunlosky, John

2013-01-01

We tested the hypothesis that feeling of knowing (FOK) after a failed recall attempt is influenced by recalling aspects of the original encoding strategy. Individuals were instructed to use interactive imagery to encode unrelated word pairs. We manipulated item concreteness (abstract versus concrete) and item repetition at study (1 versus 3). Participants orally described the mediator produced immediately after studying each item, if any. After a delay they were given cued recall, made FOK ratings, and attempted to recall their original mediator. Concreteness and item repetition enhanced strategy recall, which had a large effect on FOKs. Controlling on strategy recall reduced the predictive validity of FOKs for recognition memory, indicating that access to original aspects of encoding influenced FOK accuracy. Confidence judgments (CJs) for correctly recognized items covaried with FOKs, but FOKs did not fully track strategy recall associations with CJs, suggesting emergent effects of strategy cues elicited by recognition tests not accessed at the time of the FOK judgment. In summary, cue-generated access to aspects of the original encoding strategy strongly influenced episodic FOK, although other influences are also implicated. PMID:23835601

Incremental phonological encoding during unscripted sentence production

Directory of Open Access Journals (Sweden)

Florian T Jaeger

2012-11-01

Full Text Available We investigate phonological encoding during unscripted sentence production, focusing on the effect of phonological overlap on phonological encoding. Previous work on this question has almost exclusively employed isolated word production or highly scripted multiword production. These studies have led to conflicting results: some studies found that phonological overlap between two words facilitates phonological encoding, while others found inhibitory effects. One worry with many of these paradigms is that they involve processes that are not typical to everyday language use, which calls into question to what extent their findings speak to the architectures and mechanisms underlying language production. We present a paradigm to investigate the consequences of phonological overlap between words in a sentence while leaving speakers much of the lexical and structural choices typical in everyday language use. Adult native speakers of English described events in short video clips. We annotated the presence of disfluencies and the speech rate at various points throughout the sentence, as well as the constituent order. We find that phonological overlap has an inhibitory effect on phonological encoding. Specifically, if adjacent content words share their phonological onset (e.g., hand the hammer, they are preceded by production difficulty, as reflected in fluency and speech rate. We also find that this production difficulty affects speakers’ constituent order preferences during grammatical encoding. We discuss our results and previous works to isolate the properties of other paradigms that resulted in facilitatory or inhibitory results. The data from our paradigm also speak to questions about the scope of phonological planning in unscripted speech and as to whether phonological and grammatical encoding interact.

CDP a graphic system for the interactive simulation and the dynamic analysis of continuous systems

International Nuclear Information System (INIS)

Ricci, A.; Teolis, A.

1973-01-01

An IBM 2250 graphic system for the interactive simulation of continuous sytems is illustrated. Time dependent quantities can be plotted or an animated, real or schematic, representation of the system being studied can be given

Factors affecting reorganisation of memory encoding networks in temporal lobe epilepsy

Science.gov (United States)

Sidhu, M.K.; Stretton, J.; Winston, G.P.; Symms, M.; Thompson, P.J.; Koepp, M.J.; Duncan, J.S.

2015-01-01

Summary Aims In temporal lobe epilepsy (TLE) due to hippocampal sclerosis reorganisation in the memory encoding network has been consistently described. Distinct areas of reorganisation have been shown to be efficient when associated with successful subsequent memory formation or inefficient when not associated with successful subsequent memory. We investigated the effect of clinical parameters that modulate memory functions: age at onset of epilepsy, epilepsy duration and seizure frequency in a large cohort of patients. Methods We studied 53 patients with unilateral TLE and hippocampal sclerosis (29 left). All participants performed a functional magnetic resonance imaging memory encoding paradigm of faces and words. A continuous regression analysis was used to investigate the effects of age at onset of epilepsy, epilepsy duration and seizure frequency on the activation patterns in the memory encoding network. Results Earlier age at onset of epilepsy was associated with left posterior hippocampus activations that were involved in successful subsequent memory formation in left hippocampal sclerosis patients. No association of age at onset of epilepsy was seen with face encoding in right hippocampal sclerosis patients. In both left hippocampal sclerosis patients during word encoding and right hippocampal sclerosis patients during face encoding, shorter duration of epilepsy and lower seizure frequency were associated with medial temporal lobe activations that were involved in successful memory formation. Longer epilepsy duration and higher seizure frequency were associated with contralateral extra-temporal activations that were not associated with successful memory formation. Conclusion Age at onset of epilepsy influenced verbal memory encoding in patients with TLE due to hippocampal sclerosis in the speech-dominant hemisphere. Shorter duration of epilepsy and lower seizure frequency were associated with less disruption of the efficient memory encoding network whilst

Duplicability of self-interacting human genes.

LENUS (Irish Health Repository)

Pérez-Bercoff, Asa

2010-01-01

BACKGROUND: There is increasing interest in the evolution of protein-protein interactions because this should ultimately be informative of the patterns of evolution of new protein functions within the cell. One model proposes that the evolution of new protein-protein interactions and protein complexes proceeds through the duplication of self-interacting genes. This model is supported by data from yeast. We examined the relationship between gene duplication and self-interaction in the human genome. RESULTS: We investigated the patterns of self-interaction and duplication among 34808 interactions encoded by 8881 human genes, and show that self-interacting proteins are encoded by genes with higher duplicability than genes whose proteins lack this type of interaction. We show that this result is robust against the system used to define duplicate genes. Finally we compared the presence of self-interactions amongst proteins whose genes have duplicated either through whole-genome duplication (WGD) or small-scale duplication (SSD), and show that the former tend to have more interactions in general. After controlling for age differences between the two sets of duplicates this result can be explained by the time since the gene duplication. CONCLUSIONS: Genes encoding self-interacting proteins tend to have higher duplicability than proteins lacking self-interactions. Moreover these duplicate genes have more often arisen through whole-genome rather than small-scale duplication. Finally, self-interacting WGD genes tend to have more interaction partners in general in the PIN, which can be explained by their overall greater age. This work adds to our growing knowledge of the importance of contextual factors in gene duplicability.

Electrophysiological evidence for the modulation of retrieval orientation by depth of study processing.

Science.gov (United States)

Rugg, M D; Allan, K; Birch, C S

2000-07-01

Event-related potentials (ERPs) were employed to investigate whether brain activity elicited by retrieval cues in a memory test varies according to the encoding task undertaken at study. Two recognition memory test blocks were administered, preceded, in one case, by a "shallow" study task (alphabetic judgement) and, in the other case, by a "deep" task (sentence generation). ERPs elicited by the new words in each test block differed, the ERPs elicited in the block following the shallow study task exhibiting the more positive-going waveforms. This finding was taken as evidence that subjects adopt different "retrieval sets" when attempting to retrieve items that had been encoded in terms of alphabetic versus semantic attributes. Differences between the ERPs elicited by correctly classified old and new words (old/new effects) also varied with encoding task. The effects for deeply studied words resembled those found in previous ERP studies of recognition memory, whereas old/new effects for shallowly studied words were confined to a late-onsetting, right frontal positivity. Together, the findings indicate that the depth of study processing influences two kinds of memory-related neural activity, associated with memory search operations, and the processing of retrieved information, respectively.

Enhanced depth and mass resolution with HIRBS

International Nuclear Information System (INIS)

Yang, Q.; O'Connor, D.J.

1992-01-01

The extension of Rutherford backscattering spectrometry (RBS) to heavier mass projectiles (HIRBS) has been limited, as these projectiles cause much more radiation damage in the detectors and curtail their lifetime. Despite this limitation interest in the use of heavier projectiles continues as there are several significant benefits which can accrue from their use. To properly understand the interaction of heavy ions with solids a systematic study of the energy loss and straggling of MeV heavy ions has been conducted and an empirical expression for these terms has been obtained. This expression has allowed the development of a realistic computer simulation which accurately predicts the energy spectra for a wide range of energies, projectiles and targets. In parallel with that study, measurements of the depth resolution of Si/Ge multilayer films using 4-6 MeV C projectiles have been used to verify the simulation. (orig.)

Variety of Polarized Line Profiles in Interacting Supernovae

Science.gov (United States)

Hoffman, Jennifer L.; Huk, L. N.; Peters, C. L.

2013-01-01

The dense circumstellar material that creates strong emission lines in the spectra of interacting supernovae also gives rise to complex line polarization behavior. Viewed in polarized light, the emission line profiles of these supernovae encode information about the geometrical and optical characteristics of their surrounding circumstellar material (CSM) that is inaccessible by other observational techniques. To facilitate quantitative interpretation of these spectropolarimetric signatures, we have created a large grid of model polarized line profiles using a three-dimensional radiative transfer code that simulates polarization via electron and resonant/fluorescent line scattering. The simulated polarized lines take on an array of profile shapes that vary with viewing angle and CSM properties. We present the major results from the grid and investigate the dependence of polarized line profiles on CSM characteristics including temperature, optical depth, and geometry. These results will allow more straightforward interpretation of polarized line profiles in interacting supernovae than has previously been possible. This research is supported by the National Science Foundation through the AAG program and the XSEDE collaboration, and uses the resources of the Texas Advanced Computing Center.

Natural Length Scales Shape Liquid Phase Continuity in Unsaturated Flows

Science.gov (United States)

Assouline, S.; Lehmann, P. G.; Or, D.

2015-12-01

Unsaturated flows supporting soil evaporation and internal drainage play an important role in various hydrologic and climatic processes manifested at a wide range of scales. We study inherent natural length scales that govern these flow processes and constrain the spatial range of their representation by continuum models. These inherent length scales reflect interactions between intrinsic porous medium properties that affect liquid phase continuity, and the interplay among forces that drive and resist unsaturated flow. We have defined an intrinsic length scale for hydraulic continuity based on pore size distribution that controls soil evaporation dynamics (i.e., stage 1 to stage 2 transition). This simple metric may be used to delineate upper bounds for regional evaporative losses or the depth of soil-atmosphere interactions (in the absence of plants). A similar length scale governs the dynamics of internal redistribution towards attainment of field capacity, again through its effect on hydraulic continuity in the draining porous medium. The study provides a framework for guiding numerical and mathematical models for capillary flows across different scales considering the necessary conditions for coexistence of stationarity (REV), hydraulic continuity and intrinsic capillary gradients.

Shave-off depth profiling: Depth profiling with an absolute depth scale

International Nuclear Information System (INIS)

Nojima, M.; Maekawa, A.; Yamamoto, T.; Tomiyasu, B.; Sakamoto, T.; Owari, M.; Nihei, Y.

2006-01-01

Shave-off depth profiling provides profiling with an absolute depth scale. This method uses a focused ion beam (FIB) micro-machining process to provide the depth profile. We show that the shave-off depth profile of a particle reflected the spherical shape of the sample and signal intensities had no relationship to the depth. Through the introduction of FIB micro-sampling, the shave-off depth profiling of a dynamic random access memory (DRAM) tip was carried out. The shave-off profile agreed with a blue print from the manufacturing process. Finally, shave-off depth profiling is discussed with respect to resolutions and future directions

Λ and Σ well depth

International Nuclear Information System (INIS)

Satoh, Eiji

1982-01-01

The Λ well depth was calculated by taking into account the effect of the ΛΣ conversion. Takahashi et al. obtained the separate type of potentials which described the hyperon-nucleon interaction up to p waves. Two types of the potentials among several types they obtained were used to calculate the Λ well depth. The G matrix was easily calculated, and the Λ well depth was obtained by integrating the G matrix in momentum space up to the Fermi surface. The effect of the ΛΣ conversion was given by an equation. The total Λ well depth was estimated to be 9.13 MeV and 49.36 MeV for each type of potential, respectively. It was concluded that the argument by Bodmer et al. was not correct. The Σ well depth was also calculated using the potential obtained by Takahashi et al. for I = 1/2 and the one obtained by Σ + p → Σ + p scattering data for I = 3/2. The obtained value 35.30 MeV may be overestimated, and the experimental value is expected to be in the range from 20 MeV to 30 MeV. (Ito, K.)

High resolution detectors based on continuous crystals and SiPMs for small animal PET

International Nuclear Information System (INIS)

Cabello, J.; Barrillon, P.; Barrio, J.; Bisogni, M.G.; Del Guerra, A.; Lacasta, C.; Rafecas, M.; Saikouk, H.; Solaz, C.; Solevi, P.; La Taille, C. de; Llosá, G.

2013-01-01

Sensitivity and spatial resolution are the two main factors to maximize in emission imaging. The improvement of one factor deteriorates the other with pixelated crystals. In this work we combine SiPM matrices with monolithic crystals, using an accurate γ-ray interaction position determination algorithm that provides depth of interaction. Continuous crystals provide higher sensitivity than pixelated crystals, while an accurate interaction position determination does not degrade the spatial resolution. Monte Carlo simulations and experimental data show good agreement both demonstrating sub-millimetre intrinsic spatial resolution. A system consisting in two rotating detectors in coincidence is currently under operation already producing tomographic images

Semi-Automatic Image Labelling Using Depth Information

Directory of Open Access Journals (Sweden)

Mostafa Pordel

2015-05-01

Full Text Available Image labeling tools help to extract objects within images to be used as ground truth for learning and testing in object detection processes. The inputs for such tools are usually RGB images. However with new widely available low-cost sensors like Microsoft Kinect it is possible to use depth images in addition to RGB images. Despite many existing powerful tools for image labeling, there is a need for RGB-depth adapted tools. We present a new interactive labeling tool that partially automates image labeling, with two major contributions. First, the method extends the concept of image segmentation from RGB to RGB-depth using Fuzzy C-Means clustering, connected component labeling and superpixels, and generates bounding pixels to extract the desired objects. Second, it minimizes the interaction time needed for object extraction by doing an efficient segmentation in RGB-depth space. Very few clicks are needed for the entire procedure compared to existing, tools. When the desired object is the closest object to the camera, which is often the case in robotics applications, no clicks at all are required to accurately extract the object.

Z-depth integration: a new technique for manipulating z-depth properties in composited scenes

Science.gov (United States)

Steckel, Kayla; Whittinghill, David

2014-02-01

This paper presents a new technique in the production pipeline of asset creation for virtual environments called Z-Depth Integration (ZeDI). ZeDI is intended to reduce the time required to place elements at the appropriate z-depth within a scene. Though ZeDI is intended for use primarily in two-dimensional scene composition, depth-dependent "flat" animated objects are often critical elements of augmented and virtual reality applications (AR/VR). ZeDI is derived from "deep image compositing", a capacity implemented within the OpenEXR file format. In order to trick the human eye into perceiving overlapping scene elements as being in front of or behind one another, the developer must manually manipulate which pixels of an element are visible in relation to other objects embedded within the environment's image sequence. ZeDI improves on this process by providing a means for interacting with procedurally extracted z-depth data from a virtual environment scene. By streamlining the process of defining objects' depth characteristics, it is expected that the time and energy required for developers to create compelling AR/VR scenes will be reduced. In the proof of concept presented in this manuscript, ZeDI is implemented for pre-rendered virtual scene construction via an AfterEffects software plug-in.

Movement Interferes with Visuospatial Working Memory during the Encoding: An ERP Study

Directory of Open Access Journals (Sweden)

Rumeysa Gunduz Can

2017-05-01

Full Text Available The present study focuses on the functional interactions of cognition and manual action control. Particularly, we investigated the neurophysiological correlates of the dual-task costs of a manual-motor task (requiring grasping an object, holding it, and subsequently placing it on a target for working memory (WM domains (verbal and visuospatial and processes (encoding and retrieval. Thirty participants were tested in a cognitive-motor dual-task paradigm, in which a single block (a verbal or visuospatial WM task was compared with a dual block (concurrent performance of a WM task and a motor task. Event-related potentials (ERPs were analyzed separately for the encoding and retrieval processes of verbal and visuospatial WM domains both in single and dual blocks. The behavioral analyses show that the motor task interfered with WM and decreased the memory performance. The performance decrease was larger for the visuospatial task compared with the verbal task, i.e., domain-specific memory costs were obtained. The ERP analyses show the domain-specific interference also at the neurophysiological level, which is further process-specific to encoding. That is, comparing the patterns of WM-related ERPs in the single block and dual block, we showed that visuospatial ERPs changed only for the encoding process when a motor task was performed at the same time. Generally, the present study provides evidence for domain- and process-specific interactions of a prepared manual-motor movement with WM (visuospatial domain during the encoding process. This study, therefore, provides an initial neurophysiological characterization of functional interactions of WM and manual actions in a cognitive-motor dual-task setting, and contributes to a better understanding of the neuro-cognitive mechanisms of motor action control.

Cloning of gene-encoded stem bromelain on system coming from Pichia pastoris as therapeutic protein candidate

Science.gov (United States)

Yusuf, Y.; Hidayati, W.

2018-01-01

The process of identifying bacterial recombination using PCR, and restriction, and then sequencing process was done after identifying the bacteria. This research aimed to get a yeast cell of Pichia pastoris which has an encoder gene of stem bromelain enzyme. The production of recombinant stem bromelain enzymes using yeast cells of P. pastoris can produce pure bromelain rod enzymes and have the same conformation with the enzyme’s conformation in pineapple plants. This recombinant stem bromelain enzyme can be used as a therapeutic protein in inflammatory, cancer and degenerative diseases. This study was an early stage of a step series to obtain bromelain rod protein derived from pineapple made with genetic engineering techniques. This research was started by isolating the RNA of pineapple stem which was continued with constructing cDNA using reserve transcriptase-PCR technique (RT-PCR), doing the amplification of bromelain enzyme encoder gene with PCR technique using a specific premiere couple which was designed. The process was continued by cloning into bacterium cells of Escherichia coli. A vector which brought the encoder gene of stem bromelain enzyme was inserted into the yeast cell of P. pastoris and was continued by identifying the yeast cell of P. pastoris which brought the encoder gene of stem bromelain enzyme. The research has not found enzyme gene of stem bromelain in yeast cell of P. pastoris yet. The next step is repeating the process by buying new reagent; RNase inhibitor, and buying liquid nitrogen.

Growing season methane emission from a boreal peatland in the continuous permafrost zone of Northeast China: effects of active layer depth and vegetation

Directory of Open Access Journals (Sweden)

Y. Miao

2012-11-01

Full Text Available Boreal peatlands are significant natural sources of methane and especially vulnerable to abrupt climate change. However, the controlling factors of CH₄ emission in boreal peatlands are still unclear. In this study, we investigated CH₄ fluxes and abiotic factors (temperature, water table depth, active layer depth, and dissolved CH₄ concentrations in pore water during the growing seasons in 2010 and 2011 in both shrub-sphagnum- and sedge-dominated plant communities in the continuous permafrost zone of Northeast China. The objective of our study was to examine the effects of vegetation types and abiotic factors on CH₄ fluxes from a boreal peatland. In an Eriophorum-dominated community, mean CH₄ emissions were 1.02 and 0.80 mg m⁻² h⁻¹ in 2010 and 2011, respectively. CH₄ fluxes (0.38 mg m⁻² h⁻¹ released from the shrub-mosses-dominated community were lower than that from Eriophorum-dominated community. Moreover, in the Eriophorum-dominated community, CH₄ fluxes showed a significant temporal pattern with a peak value in late August in both 2010 and 2011. However, no distinct seasonal variation was observed in the CH₄ flux in the shrub-mosses-dominated community. Interestingly, in both Eriophorum- and shrub-sphagnum-dominated communities, CH₄ fluxes did not show close correlation with air or soil temperature and water table depth, whereas CH₄ emissions correlated well to active layer depth and CH₄ concentration in soil pore water, especially in the Eriophorum-dominated community. Our results suggest that CH₄ released from the thawed CH₄-rich permafrost layer may be a key factor controlling CH₄ emissions in boreal peatlands, and highlight that CH₄ fluxes vary with vegetation type in boreal peatlands. With

Building on prior knowledge: schema-dependent encoding processes relate to academic performance.

Science.gov (United States)

van Kesteren, Marlieke T R; Rijpkema, Mark; Ruiter, Dirk J; Morris, Richard G M; Fernández, Guillén

2014-10-01

The acquisition and retention of conceptual knowledge is more effective in well-structured curricula that provide an optimal conceptual framework for learning new material. However, the neural mechanisms by which preexisting conceptual schemas facilitate learning are not yet well understood despite their fundamental importance. A preexisting schema has been shown to enhance memory by influencing the balance between activity within the medial-temporal lobe and the medial pFC during mnemonic processes such as encoding, consolidation, and retrieval. Specifically, correctly encoding and retrieving information that is related to preexisting schemas appears rather related to medial prefrontal processing, whereas information unrelated or inconsistent with preexisting schemas rather relates to enhanced medial temporal processing and enhanced interaction between these structures. To further investigate interactions between these regions during conceptual encoding in a real-world university setting, we probed human brain activity and connectivity using fMRI during educationally relevant conceptual encoding carefully embedded within two course programs. Early second-year undergraduate biology and education students were scanned while encoding new facts that were either related or unrelated to the preexisting conceptual knowledge they had acquired during their first year of study. Subsequently, they were tested on their knowledge of these facts 24 hr later. Memory scores were better for course-related information, and this enhancement was associated with larger medial-prefrontal, but smaller medial-temporal subsequent memory effects. These activity differences went along with decreased functional interactions between these regions. Furthermore, schema-related medial-prefrontal subsequent memory effects measured during this experiment were found to be predictive of second-year course performance. These results, obtained in a real-world university setting, reveal brain

The posterior medial cortex is involved in visual but not in verbal memory encoding processing: an intracerebral recording study.

Science.gov (United States)

Stillová, K; Jurák, P; Chládek, J; Halámek, J; Telecká, S; Rektor, I

2013-03-01

The objective is to study the involvement of the posterior medial cortex (PMC) in encoding and retrieval by visual and auditory memory processing. Intracerebral recordings were studied in two epilepsy-surgery candidates with depth electrodes implanted in the retrosplenial cingulate, precuneus, cuneus, lingual gyrus and hippocampus. We recorded the event-related potentials (ERP) evoked by visual and auditory memory encoding-retrieval tasks. In the hippocampus, ERP were elicited in the encoding and retrieval phases in the two modalities. In the PMC, ERP were recorded in both the encoding and the retrieval visual tasks; in the auditory modality, they were recorded in the retrieval task, but not in the encoding task. In conclusion, the PMC is modality dependent in memory processing. ERP is elicited by memory retrieval, but it is not elicited by auditory encoding memory processing in the PMC. The PMC appears to be involved not only in higher-order top-down cognitive activities but also in more basic, rather than bottom-up activities.

Hydrologic controls on equilibrium soil depths

Science.gov (United States)

Nicótina, L.; Tarboton, D. G.; Tesfa, T. K.; Rinaldo, A.

2011-04-01

This paper deals with modeling the mutual feedbacks between runoff production and geomorphological processes and attributes that lead to patterns of equilibrium soil depth. Our primary goal is an attempt to describe spatial patterns of soil depth resulting from long-term interactions between hydrologic forcings and soil production, erosion, and sediment transport processes under the framework of landscape dynamic equilibrium. Another goal is to set the premises for exploiting the role of soil depths in shaping the hydrologic response of a catchment. The relevance of the study stems from the massive improvement in hydrologic predictions for ungauged basins that would be achieved by using directly soil depths derived from geomorphic features remotely measured and objectively manipulated. Hydrological processes are here described by explicitly accounting for local soil depths and detailed catchment topography. Geomorphological processes are described by means of well-studied geomorphic transport laws. The modeling approach is applied to the semiarid Dry Creek Experimental Watershed, located near Boise, Idaho. Modeled soil depths are compared with field data obtained from an extensive survey of the catchment. Our results show the ability of the model to describe properly the mean soil depth and the broad features of the distribution of measured data. However, local comparisons show significant scatter whose origins are discussed.

Interactive Exploration for Continuously Expanding Neuron Databases.

Science.gov (United States)

Li, Zhongyu; Metaxas, Dimitris N; Lu, Aidong; Zhang, Shaoting

2017-02-15

This paper proposes a novel framework to help biologists explore and analyze neurons based on retrieval of data from neuron morphological databases. In recent years, the continuously expanding neuron databases provide a rich source of information to associate neuronal morphologies with their functional properties. We design a coarse-to-fine framework for efficient and effective data retrieval from large-scale neuron databases. In the coarse-level, for efficiency in large-scale, we employ a binary coding method to compress morphological features into binary codes of tens of bits. Short binary codes allow for real-time similarity searching in Hamming space. Because the neuron databases are continuously expanding, it is inefficient to re-train the binary coding model from scratch when adding new neurons. To solve this problem, we extend binary coding with online updating schemes, which only considers the newly added neurons and update the model on-the-fly, without accessing the whole neuron databases. In the fine-grained level, we introduce domain experts/users in the framework, which can give relevance feedback for the binary coding based retrieval results. This interactive strategy can improve the retrieval performance through re-ranking the above coarse results, where we design a new similarity measure and take the feedback into account. Our framework is validated on more than 17,000 neuron cells, showing promising retrieval accuracy and efficiency. Moreover, we demonstrate its use case in assisting biologists to identify and explore unknown neurons. Copyright © 2017 Elsevier Inc. All rights reserved.

Understanding of CO{sub 2} interaction with thermally grown SiO{sub 2} on Si using IBA depth profiling techniques

Energy Technology Data Exchange (ETDEWEB)

Deokar, Geetanjali; D’Angelo, Marie; Briand, Emrick [INSP, UPMC, CNRS UMR 7588, 4 Place Jussieu, Paris F-75005 (France); Deville Cavellin, Catherine, E-mail: deville@univ-paris12.fr [INSP, UPMC, CNRS UMR 7588, 4 Place Jussieu, Paris F-75005 (France); Faculté des Sciences et Technologie UPEC, 61 Av., De Gaulle, Créteil F-94010 (France)

2013-06-01

Interactions between CO{sub 2} and SiO{sub 2} films thermally grown on Si have been studied using {sup 18}O and {sup 13}C as isotopic tracers associated with ion beam analysis (IBA) depth profiling techniques. From secondary ion mass spectrometry (SIMS) measurements no carbon from CO{sub 2} is detected in the silica while it is found in Si. These results suggest that CO{sub 2} diffuses through the silica. Exchanges of oxygen between CO{sub 2} and silica can be observed from {sup 18}O to {sup 16}O SIMS signals variation. The oxygen concentration depth profiles were determined quantitatively using the narrow resonance near 151 keV in the {sup 18}O(p,α){sup 15}N nuclear reaction (Narrow Resonance Profiling, NRP). We demonstrate that two distinct oxygen exchanges processes co-exist and we determine the diffusion coefficient of the CO{sub 2} molecule in the silica at 1100 °C.

Development of Cold Neutron Depth Profiling System at HANARO

International Nuclear Information System (INIS)

Park, B. G.; Choi, H. D.; Sun, G. M.

2012-01-01

The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. A number of analytical techniques for depth profiling have been developed. Neutron Depth Profiling (NDP) system which was developed by Ziegler et al. is one of the leading analytical techniques. In NDP, a thermal or cold neutron beam passes through a material and interacts with certain isotopes that are known to emit monoenergetic-charged particle remaining a recoil nucleus after neutron absorption. The depth is obtained from the energy loss of those charged particles escaping surface of substrate material. For various applications of NDP technique, the Cold Neutron Depth Profiling System (CN-NDP) was developed at a neutron guide CG1 installed at the HANARO cold neutron source. In this study the design features of the cold neutron beam and target chamber for the CN-NDP system are given. Also, some experiments for the performance tests of the CN-NDP system are described

Three-dimensional trace measurements for fast-moving objects using binary-encoded fringe projection techniques.

Science.gov (United States)

Su, Wei-Hung; Kuo, Cho-Yo; Kao, Fu-Jen

2014-08-20

A fringe projection technique to trace the shape of a fast-moving object is proposed. A binary-encoded fringe pattern is illuminated by a strobe lamp and then projected onto the moving object at a sequence of time. Phases of the projected fringes obtained from the sequent measurements are extracted by the Fourier transform method. Unwrapping is then performed with reference to the binary-encoded fringe pattern. Even though the inspected object is colorful, fringe orders can be identified. A stream of profiles is therefore retrieved from the sequent unwrapped phases. This makes it possible to analyze physical properties of the dynamic objects. Advantages of the binary-encoded fringe pattern for phase unwrapping also include (1) reliable performance for colorful objects, spatially isolated objects, and surfaces with large depth discontinuities; (2) unwrapped errors only confined in a local area; and (3) low computation cost.

Depth dependent stress revealed by aftershocks

Science.gov (United States)

Narteau, C.; Shebalin, P.

2017-12-01

Aftershocks occur in response to perturbations of the state of stress induced either by earthquakes or human activities. Along major strike-slip fault segments of the San Andreas fault system, the time-delay before the onset of the power-law aftershock decay rate (the c-value) varies by three orders of magnitude in the first twenty kilometers below the surface. Despite the influence of the lithostatic stress, there is no continuous change in c-value with respect to depth. Instead, two decay phases are separated by an abrupt increase at an intermediate depth range of 2 to 5 km. This transitional regime is the only one observed in fluid-injection-induced seismic areas. This provides strong evidence for the role of fluid and a porosity reduction mechanism at depth of few kilometers in active fault zones. Aftershock statistics can then be used to predict the evolution the differential shear stress with depth until the brittle-ductile transition is reached.

The spectro-contextual encoding and retrieval theory of episodic memory.

Science.gov (United States)

Watrous, Andrew J; Ekstrom, Arne D

2014-01-01

The spectral fingerprint hypothesis, which posits that different frequencies of oscillations underlie different cognitive operations, provides one account for how interactions between brain regions support perceptual and attentive processes (Siegel etal., 2012). Here, we explore and extend this idea to the domain of human episodic memory encoding and retrieval. Incorporating findings from the synaptic to cognitive levels of organization, we argue that spectrally precise cross-frequency coupling and phase-synchronization promote the formation of hippocampal-neocortical cell assemblies that form the basis for episodic memory. We suggest that both cell assembly firing patterns as well as the global pattern of brain oscillatory activity within hippocampal-neocortical networks represents the contents of a particular memory. Drawing upon the ideas of context reinstatement and multiple trace theory, we argue that memory retrieval is driven by internal and/or external factors which recreate these frequency-specific oscillatory patterns which occur during episodic encoding. These ideas are synthesized into a novel model of episodic memory (the spectro-contextual encoding and retrieval theory, or "SCERT") that provides several testable predictions for future research.

Encoding qubits into oscillators with atomic ensembles and squeezed light

Science.gov (United States)

Motes, Keith R.; Baragiola, Ben Q.; Gilchrist, Alexei; Menicucci, Nicolas C.

2017-05-01

The Gottesman-Kitaev-Preskill (GKP) encoding of a qubit within an oscillator provides a number of advantages when used in a fault-tolerant architecture for quantum computing, most notably that Gaussian operations suffice to implement all single- and two-qubit Clifford gates. The main drawback of the encoding is that the logical states themselves are challenging to produce. Here we present a method for generating optical GKP-encoded qubits by coupling an atomic ensemble to a squeezed state of light. Particular outcomes of a subsequent spin measurement of the ensemble herald successful generation of the resource state in the optical mode. We analyze the method in terms of the resources required (total spin and amount of squeezing) and the probability of success. We propose a physical implementation using a Faraday-based quantum nondemolition interaction.

Event-related rTMS at encoding affects differently deep and shallow memory traces.

Science.gov (United States)

Innocenti, Iglis; Giovannelli, Fabio; Cincotta, Massimo; Feurra, Matteo; Polizzotto, Nicola R; Bianco, Giovanni; Cappa, Stefano F; Rossi, Simone

2010-10-15

The "level of processing" effect is a classical finding of the experimental psychology of memory. Actually, the depth of information processing at encoding predicts the accuracy of the subsequent episodic memory performance. When the incoming stimuli are analyzed in terms of their meaning (semantic, or deep, encoding), the memory performance is superior with respect to the case in which the same stimuli are analyzed in terms of their perceptual features (shallow encoding). As suggested by previous neuroimaging studies and by some preliminary findings with transcranial magnetic stimulation (TMS), the left prefrontal cortex may play a role in semantic processing requiring the allocation of working memory resources. However, it still remains unclear whether deep and shallow encoding share or not the same cortical networks, as well as how these networks contribute to the "level of processing" effect. To investigate the brain areas casually involved in this phenomenon, we applied event-related repetitive TMS (rTMS) during deep (semantic) and shallow (perceptual) encoding of words. Retrieval was subsequently tested without rTMS interference. RTMS applied to the left dorsolateral prefrontal cortex (DLPFC) abolished the beneficial effect of deep encoding on memory performance, both in terms of accuracy (decrease) and reaction times (increase). Neither accuracy nor reaction times were instead affected by rTMS to the right DLPFC or to an additional control site excluded by the memory process (vertex). The fact that online measures of semantic processing at encoding were unaffected suggests that the detrimental effect on memory performance for semantically encoded items took place in the subsequent consolidation phase. These results highlight the specific causal role of the left DLPFC among the wide left-lateralized cortical network engaged by long-term memory, suggesting that it probably represents a crucial node responsible for the improved memory performance induced by

Recognition memory is improved by a structured temporal framework during encoding

Directory of Open Access Journals (Sweden)

Sathesan eThavabalasingam

2016-01-01

Full Text Available In order to function optimally within our environment, we continuously extract temporal patterns from our experiences and formulate expectations that facilitate adaptive behavior. Given that our memories are embedded within spatiotemporal contexts, an intriguing possibility is that mnemonic processes are sensitive to the temporal structure of events. To test this hypothesis, in a series of behavioral experiments we manipulated the regularity of interval durations at encoding to create temporally structured and unstructured frameworks. Our findings revealed enhanced recognition memory (d’ for stimuli that were explicitly encoded within a temporally structured versus unstructured framework. Encoding information within a temporally structured framework was also associated with a reduction in the negative effects of proactive interference and was linked to greater recollective recognition memory. Furthermore, rhythmic temporal structure was found to enhance recognition memory for incidentally encoded information. Collectively, these results support the possibility that we possess a greater capacity to learn and subsequently remember temporally structured information.

Interaction Sheaves on Continuous Domains

DEFF Research Database (Denmark)

Abdou, J.; Keiding, Hans

We introduce a description of the power structure which is inherent in a strategic game form using the concept of an interaction sheaf. The latter assigns to each open set of outcomes a set of interaction arrays, specifying the changes that coalitions can make if outcome belongs to this open set....

Interaction sheaves on continuous domains

DEFF Research Database (Denmark)

Abdou, Joseph; Keiding, Hans

2009-01-01

We introduce a description of the power structure which is inherent in a strategic game form using the concept of an interaction sheaf. The latter assigns to each open set of outcomes a set of interaction arrays, specifying the changes that coalitions can make if outcome belongs to this open set....

RFID tag modification for full depth backscatter modulation

Science.gov (United States)

Scott, Jeffrey Wayne [Pasco, WA; Pratt, Richard M [Richland, WA

2010-07-20

A modulated backscatter radio frequency identification device includes a diode detector configured to selectively modulate a reply signal onto an incoming continuous wave; communications circuitry configured to provide a modulation control signal to the diode detector, the diode detector being configured to modulate the reply signal in response to be modulation control signal; and circuitry configured to increase impedance change at the diode detector which would otherwise not occur because the diode detector rectifies the incoming continuous wave while modulating the reply signal, whereby reducing the rectified signal increases modulation depth by removing the reverse bias effects on impedance changes. Methods of improving depth of modulation in a modulated backscatter radio frequency identification device are also provided.

Depth distribution of multiple order X-ray scatter

International Nuclear Information System (INIS)

Yao Weiguang; Leszczynski, Konrad

2008-01-01

Scatter can significantly affect quality of projectional X-ray radiographs and tomographic reconstructions. With this in mind, we examined some of the physical properties of multiple orders of scatter of X-ray photons traversing through a layer of scattering media such as water. Using Monte Carlo techniques, we investigated depth distributions of interactions between incident X-ray photons and water before the resulting scattered photons reach the detector plane. Effects of factors such as radiation field size, air gap, thickness of the layer of scattering medium and X-ray energy, on the scatter were included in the scope of this study. The following scatter characteristics were observed: (1) for a layer of scattering material corresponding to the typical subject thickness in medical imaging, frequency distribution of locations of the last scattering interaction increases approximately exponentially with depth, and the higher the order of scatter or the energy of the incident photon, the narrower is the distribution; (2) for the second order scatter, the distribution of locations of the first interaction is more uniform than that of the last interaction and is dependent on the energy of the primary photons. Theoretical proofs for some of these properties are given. These properties are important to better understanding of effects of scatter on the radiographic and tomographic imaging process and to developing effective methods for scatter correction

Evaluation of Depth of Field for depth perception in DVR

KAUST Repository

Grosset, A.V.Pascal; Schott, Mathias; Bonneau, Georges-Pierre; Hansen, Charles D.

2013-01-01

In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

Evaluation of Depth of Field for depth perception in DVR

KAUST Repository

Grosset, A.V.Pascal

2013-02-01

In this paper we present a user study on the use of Depth of Field for depth perception in Direct Volume Rendering. Direct Volume Rendering with Phong shading and perspective projection is used as the baseline. Depth of Field is then added to see its impact on the correct perception of ordinal depth. Accuracy and response time are used as the metrics to evaluate the usefulness of Depth of Field. The onsite user study has two parts: static and dynamic. Eye tracking is used to monitor the gaze of the subjects. From our results we see that though Depth of Field does not act as a proper depth cue in all conditions, it can be used to reinforce the perception of which feature is in front of the other. The best results (high accuracy & fast response time) for correct perception of ordinal depth occurs when the front feature (out of the two features users were to choose from) is in focus and perspective projection is used. © 2013 IEEE.

Angular Gyrus Involvement at Encoding and Retrieval Is Associated with Durable But Less Specific Memories.

Science.gov (United States)

van der Linden, Marieke; Berkers, Ruud M W J; Morris, Richard G M; Fernández, Guillén

2017-09-27

After consolidation, information belonging to a mental schema is better remembered, but such memory can be less specific when it comes to details. A neuronal mechanism consistent with this behavioral pattern could result from a dynamic interaction that entails mediation by a specific cortical network with associated hippocampal disengagement. We now report that, in male and female adult human subjects, encoding and later consolidation of a series of objects embedded in a semantic schema was associated with a buildup of activity in the angular gyrus (AG) that predicted memory 24 h later. In parallel, the posterior hippocampus became less involved as schema objects were encoded successively. Hippocampal disengagement was related to an increase in falsely remembering objects that were not presented at encoding. During both encoding and retrieval, the AG and lateral occipital complex (LOC) became functionally connected and this interaction was beneficial for successful retrieval. Therefore, a network including the AG and LOC enhances the overnight retention of schema-related memories and their simultaneous detachment from the hippocampus reduces the specificity of the memory. SIGNIFICANCE STATEMENT This study provides the first empirical evidence on how the hippocampus and the neocortex interact dynamically when acquiring and then effectively retaining durable knowledge that is associated to preexisting knowledge, but they do so at the cost of memory specificity. This interaction is a fundamental mnemonic operation that has thus far been largely overlooked in memory research. Copyright © 2017 the authors 0270-6474/17/379474-12$15.00/0.

Multimodal ophthalmic imaging using spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography

Science.gov (United States)

El-Haddad, Mohamed T.; Malone, Joseph D.; Li, Jianwei D.; Bozic, Ivan; Arquitola, Amber M.; Joos, Karen M.; Patel, Shriji N.; Tao, Yuankai K.

2017-08-01

Ophthalmic surgery involves manipulation of delicate, layered tissue structures on milli- to micrometer scales. Traditional surgical microscopes provide an inherently two-dimensional view of the surgical field with limited depth perception which precludes accurate depth-resolved visualization of these tissue layers, and limits the development of novel surgical techniques. We demonstrate multimodal swept-source spectrally encoded scanning laser ophthalmoscopy and optical coherence tomography (SS-SESLO-OCT) to address current limitations of image-guided ophthalmic microsurgery. SS-SESLO-OCT provides inherently co-registered en face and cross-sectional field-of-views (FOVs) at a line rate of 400 kHz and >2 GPix/s throughput. We show in vivo imaging of the anterior segment and retinal fundus of a healthy volunteer, and preliminary results of multi-volumetric mosaicking for ultrawide-field retinal imaging with 90° FOV. Additionally, a scan-head was rapid-prototyped with a modular architecture which enabled integration of SS-SESLO-OCT with traditional surgical microscope and slit-lamp imaging optics. Ex vivo surgical maneuvers were simulated in cadaveric porcine eyes. The system throughput enabled volumetric acquisition at 10 volumes-per-second (vps) and allowed visualization of surgical dynamics in corneal sweeps, compressions, and dissections, and retinal sweeps, compressions, and elevations. SESLO en face images enabled simple real-time co-registration with the surgical microscope FOV, and OCT cross-sections provided depth-resolved visualization of instrument-tissue interactions. Finally, we demonstrate novel augmented-reality integration with the surgical view using segmentation overlays to aid surgical guidance. SS-SESLO-OCT may benefit clinical diagnostics by enabling aiming, registration, and mosaicking; and intraoperative imaging by allowing for real-time surgical feedback, instrument tracking, and overlays of computationally extracted biomarkers of disease.

Chromatic confocal microscopy for multi-depth imaging of epithelial tissue

Science.gov (United States)

Olsovsky, Cory; Shelton, Ryan; Carrasco-Zevallos, Oscar; Applegate, Brian E.; Maitland, Kristen C.

2013-01-01

We present a novel chromatic confocal microscope capable of volumetric reflectance imaging of microstructure in non-transparent tissue. Our design takes advantage of the chromatic aberration of aspheric lenses that are otherwise well corrected. Strong chromatic aberration, generated by multiple aspheres, longitudinally disperses supercontinuum light onto the sample. The backscattered light detected with a spectrometer is therefore wavelength encoded and each spectrum corresponds to a line image. This approach obviates the need for traditional axial mechanical scanning techniques that are difficult to implement for endoscopy and susceptible to motion artifact. A wavelength range of 590-775 nm yielded a >150 µm imaging depth with ~3 µm axial resolution. The system was further demonstrated by capturing volumetric images of buccal mucosa. We believe these represent the first microstructural images in non-transparent biological tissue using chromatic confocal microscopy that exhibit long imaging depth while maintaining acceptable resolution for resolving cell morphology. Miniaturization of this optical system could bring enhanced speed and accuracy to endomicroscopic in vivo volumetric imaging of epithelial tissue. PMID:23667789

Displacement encoder

International Nuclear Information System (INIS)

Hesketh, T.G.

1983-01-01

In an optical encoder, light from an optical fibre input A is encoded by means of the encoding disc and is subsequently collected for transmission via optical fibre B. At some point in the optical path between the fibres A and B, the light is separated into component form by means of a filtering or dispersive system and each colour component is associated with a respective one of the coding channels of the disc. In this way, the significance of each bit of the coded information is represented by a respective colour thereby enabling the components to be re-combined for transmission by the fibre B without loss of information. (author)

Topological and organizational properties of the products of house-keeping and tissue-specific genes in protein-protein interaction networks.

Science.gov (United States)

Lin, Wen-Hsien; Liu, Wei-Chung; Hwang, Ming-Jing

2009-03-11

Human cells of various tissue types differ greatly in morphology despite having the same set of genetic information. Some genes are expressed in all cell types to perform house-keeping functions, while some are selectively expressed to perform tissue-specific functions. In this study, we wished to elucidate how proteins encoded by human house-keeping genes and tissue-specific genes are organized in human protein-protein interaction networks. We constructed protein-protein interaction networks for different tissue types using two gene expression datasets and one protein-protein interaction database. We then calculated three network indices of topological importance, the degree, closeness, and betweenness centralities, to measure the network position of proteins encoded by house-keeping and tissue-specific genes, and quantified their local connectivity structure. Compared to a random selection of proteins, house-keeping gene-encoded proteins tended to have a greater number of directly interacting neighbors and occupy network positions in several shortest paths of interaction between protein pairs, whereas tissue-specific gene-encoded proteins did not. In addition, house-keeping gene-encoded proteins tended to connect with other house-keeping gene-encoded proteins in all tissue types, whereas tissue-specific gene-encoded proteins also tended to connect with other tissue-specific gene-encoded proteins, but only in approximately half of the tissue types examined. Our analysis showed that house-keeping gene-encoded proteins tend to occupy important network positions, while those encoded by tissue-specific genes do not. The biological implications of our findings were discussed and we proposed a hypothesis regarding how cells organize their protein tools in protein-protein interaction networks. Our results led us to speculate that house-keeping gene-encoded proteins might form a core in human protein-protein interaction networks, while clusters of tissue-specific gene-encoded

The case for transparent depth display

NARCIS (Netherlands)

Kooi, F.L.

2003-01-01

Purpose: The continuing developments in display technology have resulted in the ability to present increasing amounts of data on computer displays. One of the coming break-throughs is generally believed to be the introduction of '3-D displays': displays with a true sense of depth. Though these types

Depth and elaboration of processing in relation to age.

Science.gov (United States)

Simon, E

1979-03-01

Processing at encoding and retrieval was jointly manipulated, and then the retrieval effectiveness of different cues was directly compared to uncover the relative pattern of deep and elaborate processing in relation to both age and different experimental manipulations. In experiment 1 phonemic and semantic cues were effective retrieval aids for to-be-remembered words in the youngest group; with increasing age, semantic cues decreased in effectiveness more than phonemic cues. These data showed phonemic features to have an importance that is not recognized in the data generated by the typical levels paradigm. When elaboration of the words was induced in Experiment 2 by presenting them in sentences, semantic and context cues were most effective in the youngest group whereas phonemic cues were most effective in the oldest group. Since the pattern of cue effectiveness in the elderly was similar to that in Experiment 1, where the same words were presented alone, it was concluded that aging results in poor elaboration, in particular, in inefficient integration of word events with the context of presentation. These age effects were mimicked in young subjects in Experiment 3 by experimentally restricting encoding time. The present approach uses somewhat modified views of depth and elaboration.

Encoding asymmetry of the N-glycosylation motif facilitates glycoprotein evolution.

Directory of Open Access Journals (Sweden)

Ryan Williams

Full Text Available Protein N-glycosylation is found in all domains of life and has a conserved role in glycoprotein folding and stability. In animals, glycoproteins transit through the Golgi where the N-glycans are trimmed and rebuilt with sequences that bind lectins, an innovation that greatly increases structural diversity and redundancy of glycoprotein-lectin interaction at the cell surface. Here we ask whether the natural tension between increasing diversity (glycan-protein interactions and site multiplicity (backup and status quo might be revealed by a phylogenic examination of glycoproteins and NXS/T(X ≠ P N-glycosylation sites. Site loss is more likely by mutation at Asn encoded by two adenosine (A-rich codons, while site gain is more probable by generating Ser or Thr downstream of an existing Asn. Thus mutations produce sites at novel positions more frequently than the reversal of recently lost sites, and therefore more paths though sequence space are made available to natural selection. An intra-species comparison of secretory and cytosolic proteins revealed a departure from equilibrium in sequences one-mutation-away from NXS/T and in (A content, indicating strong selective pressures and exploration of N-glycosylation positions during vertebrate evolution. Furthermore, secretory proteins have evolved at rates proportional to N-glycosylation site number, indicating adaptive interactions between the N-glycans and underlying protein. Given the topology of the genetic code, mutation of (A is more often nonsynonomous, and Lys, another target of many PTMs, is also encoded by two (A-rich codons. An examination of acetyl-Lys sites in proteins indicated similar evolutionary dynamics, consistent with asymmetry of the target and recognition portions of modified sites. Our results suggest that encoding asymmetry is an ancient mechanism of evolvability that increases diversity and experimentation with PTM site positions. Strong selective pressures on PTMs may have

Contribution of stress and sex hormones to memory encoding.

Science.gov (United States)

Merz, Christian J

2017-08-01

Distinct stages of the menstrual cycle and the intake of oral contraceptives (OC) affect sex hormone levels, stress responses, and memory processes critically involved in the pathogenesis of mental disorders. To characterize the interaction of sex and stress hormones on memory encoding, 30 men, 30 women in the early follicular phase of the menstrual cycle (FO), 30 women in the luteal phase (LU), and 30 OC women were exposed to either a stress (socially evaluated cold-pressor test) or a control condition prior to memory encoding and immediate recall of neutral, positive, and negative words. On the next day, delayed free and cued recall was tested. Sex hormone levels verified distinct estradiol, progesterone, and testosterone levels between groups. Stress increased blood pressure, cortisol concentrations, and ratings of stress appraisal in all four groups as well as cued recall performance of negative words in men. Stress exposure in OC women led to a blunted cortisol response and rather enhanced cued recall of neutral words. Thus, pre-encoding stress facilitated emotional cued recall performance in men only, but not women with different sex hormone statuses pointing to the pivotal role of circulating sex hormones in modulation of learning and memory processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Considerations of physicians about the depth of palliative sedation at the end of life

Science.gov (United States)

Swart, Siebe J.; van der Heide, Agnes; van Zuylen, Lia; Perez, Roberto S.G.M.; Zuurmond, Wouter W.A.; van der Maas, Paul J.; van Delden, Johannes J.M.; Rietjens, Judith A.C.

2012-01-01

Background: Although guidelines advise titration of palliative sedation at the end of life, in practice the depth of sedation can range from mild to deep. We investigated physicians’ considerations about the depth of continuous sedation. Methods: We performed a qualitative study in which 54 physicians underwent semistructured interviewing about the last patient for whom they had been responsible for providing continuous palliative sedation. We also asked about their practices and general attitudes toward sedation. Results: We found two approaches toward the depth of continuous sedation: starting with mild sedation and only increasing the depth if necessary, and deep sedation right from the start. Physicians described similar determinants for both approaches, including titration of sedatives to the relief of refractory symptoms, patient preferences, wishes of relatives, expert advice and esthetic consequences of the sedation. However, physicians who preferred starting with mild sedation emphasized being guided by the patient’s condition and response, and physicians who preferred starting with deep sedation emphasized ensuring that relief of suffering would be maintained. Physicians who preferred each approach also expressed different perspectives about whether patient communication was important and whether waking up after sedation is started was problematic. Interpretation: Physicians who choose either mild or deep sedation appear to be guided by the same objective of delivering sedation in proportion to the relief of refractory symptoms, as well as other needs of patients and their families. This suggests that proportionality should be seen as a multidimensional notion that can result in different approaches toward the depth of sedation. PMID:22331961

Heterarcical market: Dynamical interplay between time and space in the continuous interaction in a market model

Science.gov (United States)

Sasai, Kazuto; Gunji, Yukio-Pegio; Kinoshita, Tetsuo

2017-07-01

Multi-agent models of robust open systems such as natural systems are the important theme in the literature of systems science. Heterarchy, which means dynamical hierarchy, is a structural model, which includes the dynamical interplay between different levels. However, it is not easy to build a formal model of a heterarchical system because the interplay between different levels lead a self-referential paradox. In this paper, we propose an continuous double auction model, which includes a formal model of conitnuous transaction. We encode the model into a restriction rule of the order submittion. The proposed model shows a critical behavior of the actual markets, and it can have the relationship with the behaviors of natural systems.

Cloud-based uniform ChIP-Seq processing tools for modENCODE and ENCODE.

Science.gov (United States)

Trinh, Quang M; Jen, Fei-Yang Arthur; Zhou, Ziru; Chu, Kar Ming; Perry, Marc D; Kephart, Ellen T; Contrino, Sergio; Ruzanov, Peter; Stein, Lincoln D

2013-07-22

Funded by the National Institutes of Health (NIH), the aim of the Model Organism ENCyclopedia of DNA Elements (modENCODE) project is to provide the biological research community with a comprehensive encyclopedia of functional genomic elements for both model organisms C. elegans (worm) and D. melanogaster (fly). With a total size of just under 10 terabytes of data collected and released to the public, one of the challenges faced by researchers is to extract biologically meaningful knowledge from this large data set. While the basic quality control, pre-processing, and analysis of the data has already been performed by members of the modENCODE consortium, many researchers will wish to reinterpret the data set using modifications and enhancements of the original protocols, or combine modENCODE data with other data sets. Unfortunately this can be a time consuming and logistically challenging proposition. In recognition of this challenge, the modENCODE DCC has released uniform computing resources for analyzing modENCODE data on Galaxy (https://github.com/modENCODE-DCC/Galaxy), on the public Amazon Cloud (http://aws.amazon.com), and on the private Bionimbus Cloud for genomic research (http://www.bionimbus.org). In particular, we have released Galaxy workflows for interpreting ChIP-seq data which use the same quality control (QC) and peak calling standards adopted by the modENCODE and ENCODE communities. For convenience of use, we have created Amazon and Bionimbus Cloud machine images containing Galaxy along with all the modENCODE data, software and other dependencies. Using these resources provides a framework for running consistent and reproducible analyses on modENCODE data, ultimately allowing researchers to use more of their time using modENCODE data, and less time moving it around.

High spatial resolution measurement of depth-of-interaction of a PET LSO crystal

International Nuclear Information System (INIS)

Simon, A.; Kalinka, G.; Novak, D.; Sipos, A.; Vegh, J.; Molnar, J.

2004-01-01

Complete text of publication follows. A new type of experimental technique to investigate the depth-of-interaction (DOI) dependence in small scintillator elements designed for high-resolution animal PET [1] has been introduced at our institute, recently. A lutetium oxyorthosilicate (LSO) crystal (2x2x10 mm 3 ) was irradiated with a highly focused 2 MeV He + beam at the ATOMKI nuclear microprobe laboratory. Pulse height spectra from a photomultiplier (PMT) attached to one end of the LSO crystal were collected in list mode. Sequential scans of 1000x1000 μm 2 areas along the 10 mm long crystal were made to get high lateral resolution images of pulse height spectra at different distances from the window of the PMT. A mean pulse height algorithm was applied to each pixel to generate two dimensional intensity images and the corresponding spectra of 100 μmx1 mm areas. Representative pulse height spectra are shown in Fig. 1 for different distances between the position of irradiation and the PMT. The mean value of the pulse height spectrum describing the position of the full energy peak is a way to measure DOI effects. It is seen that the closer the DOI to the PMT-end of the crystal the higher the energy of the peak. The centre of the detected peak varies about 30 % along the lateral side of the crystal. This effect is due to the increasing number of reflections with associated loss of light when the distance between the DOI position and the light collecting PMT grows. Further these results, no difference in the light intensity was found depending on which position across (perpendicular to the length of) the crystal was irradiated with the microbeam. The obtained results of the overall DOI dependence confirm previous measurements on LSO crystals with similar geometry and wrapping but based on collimated gamma-ray irradiation. Since the present experimental setup allows obtaining data with several orders of magnitude better spatial resolution (from μm up to mm) than with

Depth sectioning using electron energy loss spectroscopy

International Nuclear Information System (INIS)

D'Alfonso, A J; Findlay, S D; Allen, L J; Cosgriff, E C; Kirkland, A I; Nellist, P D; Oxley, M P

2008-01-01

The continued development of electron probe aberration correctors for scanning transmission electron microscopy has enabled finer electron probes, allowing atomic resolution column-by-column electron energy loss spectroscopy. Finer electron probes have also led to a decrease in the probe depth of focus, facilitating optical slicing or depth sectioning of samples. The inclusion of post specimen aberration corrected image forming lenses allows for scanning confocal electron microscopy with further improved depth resolution and selectivity. We show that in both scanning transmission electron microscopy and scanning confocal electron microscopy geometries, by performing a three dimensional raster scan through a specimen and detecting electrons scattered with a characteristic energy loss, it will be possible to determine the location of isolated impurities embedded within the bulk.

Encoding of coordination complexes with XML.

Science.gov (United States)

Vinoth, P; Sankar, P

2017-09-01

An in-silico system to encode structure, bonding and properties of coordination complexes is developed. The encoding is achieved through a semantic XML markup frame. Composition of the coordination complexes is captured in terms of central atom and ligands. Structural information of central atom is detailed in terms of electron status of valence electron orbitals. The ligands are encoded with specific reference to the electron environment of ligand centre atoms. Behaviour of ligands to form low or high spin complexes is accomplished by assigning a Ligand Centre Value to every ligand based on the electronic environment of ligand centre atom. Chemical ontologies are used for categorization purpose and to control different hybridization schemes. Complexes formed by the central atoms of transition metal, non-transition elements belonging to s-block, p-block and f-block are encoded with a generic encoding platform. Complexes of homoleptic, heteroleptic and bridged types are also covered by this encoding system. Utility of the encoded system to predict redox electron transfer reaction in the coordination complexes is demonstrated with a simple application. Copyright © 2017 Elsevier Inc. All rights reserved.

Extending the fundamental imaging-depth limit of multi-photon microscopy by imaging with photo-activatable fluorophores.

Science.gov (United States)

Chen, Zhixing; Wei, Lu; Zhu, Xinxin; Min, Wei

2012-08-13

It is highly desirable to be able to optically probe biological activities deep inside live organisms. By employing a spatially confined excitation via a nonlinear transition, multiphoton fluorescence microscopy has become indispensable for imaging scattering samples. However, as the incident laser power drops exponentially with imaging depth due to scattering loss, the out-of-focus fluorescence eventually overwhelms the in-focal signal. The resulting loss of imaging contrast defines a fundamental imaging-depth limit, which cannot be overcome by increasing excitation intensity. Herein we propose to significantly extend this depth limit by multiphoton activation and imaging (MPAI) of photo-activatable fluorophores. The imaging contrast is drastically improved due to the created disparity of bright-dark quantum states in space. We demonstrate this new principle by both analytical theory and experiments on tissue phantoms labeled with synthetic caged fluorescein dye or genetically encodable photoactivatable GFP.

Feedback-tuned, noise resilient gates for encoded spin qubits

Science.gov (United States)

Bluhm, Hendrik

Spin 1/2 particles form native two level systems and thus lend themselves as a natural qubit implementation. However, encoding a single qubit in several spins entails benefits, such as reducing the resources necessary for qubit control and protection from certain decoherence channels. While several varieties of such encoded spin qubits have been implemented, accurate control remains challenging, and leakage out of the subspace of valid qubit states is a potential issue. Optimal performance typically requires large pulse amplitudes for fast control, which is prone to systematic errors and prohibits standard control approaches based on Rabi flopping. Furthermore, the exchange interaction typically used to electrically manipulate encoded spin qubits is inherently sensitive to charge noise. I will discuss all-electrical, high-fidelity single qubit operations for a spin qubit encoded in two electrons in a GaAs double quantum dot. Starting from a set of numerically optimized control pulses, we employ an iterative tuning procedure based on measured error syndromes to remove systematic errors.Randomized benchmarking yields an average gate fidelity exceeding 98 % and a leakage rate into invalid states of 0.2 %. These gates exhibit a certain degree of resilience to both slow charge and nuclear spin fluctuations due to dynamical correction analogous to a spin echo. Furthermore, the numerical optimization minimizes the impact of fast charge noise. Both types of noise make relevant contributions to gate errors. The general approach is also adaptable to other qubit encodings and exchange based two-qubit gates.

High Bit-Depth Medical Image Compression With HEVC.

Science.gov (United States)

Parikh, Saurin S; Ruiz, Damian; Kalva, Hari; Fernandez-Escribano, Gerardo; Adzic, Velibor

2018-03-01

Efficient storing and retrieval of medical images has direct impact on reducing costs and improving access in cloud-based health care services. JPEG 2000 is currently the commonly used compression format for medical images shared using the DICOM standard. However, new formats such as high efficiency video coding (HEVC) can provide better compression efficiency compared to JPEG 2000. Furthermore, JPEG 2000 is not suitable for efficiently storing image series and 3-D imagery. Using HEVC, a single format can support all forms of medical images. This paper presents the use of HEVC for diagnostically acceptable medical image compression, focusing on compression efficiency compared to JPEG 2000. Diagnostically acceptable lossy compression and complexity of high bit-depth medical image compression are studied. Based on an established medically acceptable compression range for JPEG 2000, this paper establishes acceptable HEVC compression range for medical imaging applications. Experimental results show that using HEVC can increase the compression performance, compared to JPEG 2000, by over 54%. Along with this, a new method for reducing computational complexity of HEVC encoding for medical images is proposed. Results show that HEVC intra encoding complexity can be reduced by over 55% with negligible increase in file size.

Signal processing issues for the exploitation of pulse-to-pulse encoding SAR transponders

DEFF Research Database (Denmark)

Merryman Boncori, John Peter; Schiavon, Giovanni

2008-01-01

-encoding point scatterers and distributed ones. A time-domain processing algorithm and a code synchronization procedure are proposed and validated on simulated data and on a European Remote Sensing Satellite-2 data set containing prototypes of such a device. The interaction of the transponder signal with terrain...

Continuous quantum error correction for non-Markovian decoherence

International Nuclear Information System (INIS)

Oreshkov, Ognyan; Brun, Todd A.

2007-01-01

We study the effect of continuous quantum error correction in the case where each qubit in a codeword is subject to a general Hamiltonian interaction with an independent bath. We first consider the scheme in the case of a trivial single-qubit code, which provides useful insights into the workings of continuous error correction and the difference between Markovian and non-Markovian decoherence. We then study the model of a bit-flip code with each qubit coupled to an independent bath qubit and subject to continuous correction, and find its solution. We show that for sufficiently large error-correction rates, the encoded state approximately follows an evolution of the type of a single decohering qubit, but with an effectively decreased coupling constant. The factor by which the coupling constant is decreased scales quadratically with the error-correction rate. This is compared to the case of Markovian noise, where the decoherence rate is effectively decreased by a factor which scales only linearly with the rate of error correction. The quadratic enhancement depends on the existence of a Zeno regime in the Hamiltonian evolution which is absent in purely Markovian dynamics. We analyze the range of validity of this result and identify two relevant time scales. Finally, we extend the result to more general codes and argue that the performance of continuous error correction will exhibit the same qualitative characteristics

Periodontal Pocket Depth, Hyperglycemia, and Progression of Chronic Kidney Disease: A Population-Based Longitudinal Study.

Science.gov (United States)

Chang, Jia-Feng; Yeh, Jih-Chen; Chiu, Ya-Lin; Liou, Jian-Chiun; Hsiung, Jing-Ru; Tung, Tao-Hsin

2017-01-01

No large epidemiological study has been conducted to investigate the interaction and joint effects of periodontal pocket depth and hyperglycemia on progression of chronic kidney disease in patients with periodontal diseases. Periodontal pocket depth was utilized for the grading severity of periodontal disease in 2831 patients from January 2002 to June 2013. Progression of chronic kidney disease was defined as progression of color intensity in glomerular filtration rate and albuminuria grid of updated Kidney Disease-Improving Global Outcomes guidelines. Multivariable-adjusted hazard ratios (aHR) in various models were presented across different levels of periodontal pocket depth and hemoglobin A1c (HbA1c) in forest plots and 3-dimensional histograms. During 7621 person-years of follow-up, periodontal pocket depth and HbA1C levels were robustly associated with incremental risks for progression of chronic kidney disease (aHR 3.1; 95% confidence interval [CI], 2.0-4.6 for periodontal pocket depth >4.5 mm, and 2.5; 95% CI, 1.1-5.4 for HbA1C >6.5%, respectively). The interaction between periodontal pocket depth and HbA1C on progression of chronic kidney disease was strong (P periodontal pocket depth (>4.5 mm) and higher HbA1C (>6.5%) had the greatest risk (aHR 4.2; 95% CI, 1.7-6.8) compared with the lowest aHR group (periodontal pocket depth ≤3.8 mm and HbA1C ≤6%). Our study identified combined periodontal pocket depth and HbA1C as a valuable predictor of progression of chronic kidney disease in patients with periodontal diseases. While considering the interaction between periodontal diseases and hyperglycemia, periodontal survey and optimizing glycemic control are warranted to minimize the risk of worsening renal function. Copyright © 2016 Elsevier Inc. All rights reserved.

Depth of origin and angular spectrum of sputtered atoms

International Nuclear Information System (INIS)

Vicanek, M.; Jimenez Rodriguez, J.J.; Sigmund, P.

1989-01-01

A theoretical analysis is presented of the depth of origin of atoms sputtered from a random target. The physical model aims at high energy sputtering under linear cascade conditions and assumes a dilute source of recoil atoms. The initial distribution of the recoils is assumed isotropic, and their energy distribution is E -2 like without an upper or lower cutoff. The scattering medium is either infinite or bounded by a plane surface. Atoms scatter according to the m=0 power cross section. Electronic stopping is ignored. The sputtered flux, differential in depth of origin, ejection energy and ejection angle has been evaluated by Monte Carlo simulation and by five distinct methods of solution of the linear Boltzmann equation reaching from continuous slowing down neglecting angular scattering to the P 3 approximation and a Gram-Charlier expansion going over spatial moments. The continuous slowing down approximation used in previous work leads to results that are identical to those found from a scheme that only ignores angular scattering but allows for energy loss straggling. Moreover, these predictions match more closely with the Monte Carlo results than any of the approximate analytical schemes that take account of angular scattering. The results confirm the common assertion that the depth of origin of sputtered atoms is determined mainly by the stopping of low energy recoil atoms. The effect of angular scattering turns out to be astonishingly small. The distributions in depth of origin, energy, and angle do not depend significantly on whether the scattering medium is a halfspace or an infinite medium with a reference plane. The angular spectrum comes out only very slightly over cosine from the model as it stands, in agreement with previous experience, but comments are made on essential features that are not incorporated in the physical model but might influence the angular spectrum. (orig./WL)

Detector normalization and scatter correction for the jPET-D4: A 4-layer depth-of-interaction PET scanner

Energy Technology Data Exchange (ETDEWEB)

Kitamura, Keishi [Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan)]. E-mail: kitam@shimadzu.co.jp; Ishikawa, Akihiro [Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Mizuta, Tetsuro [Shimadzu Corporation, 1 Nishinokyo-Kuwabaracho, Nakagyo-ku, Kyoto-shi, Kyoto 604-8511 (Japan); Yamaya, Taiga [National Institute of Radiological Sciences, 9-1 Anagawa-4, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Yoshida, Eiji [National Institute of Radiological Sciences, 9-1 Anagawa-4, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan); Murayama, Hideo [National Institute of Radiological Sciences, 9-1 Anagawa-4, Inage-ku, Chiba-shi, Chiba 263-8555 (Japan)

2007-02-01

The jPET-D4 is a brain positron emission tomography (PET) scanner composed of 4-layer depth-of-interaction (DOI) detectors with a large number of GSO crystals, which achieves both high spatial resolution and high scanner sensitivity. Since the sensitivity of each crystal element is highly dependent on DOI layer depth and incidental {gamma} ray energy, it is difficult to estimate normalization factors and scatter components with high statistical accuracy. In this work, we implemented a hybrid scatter correction method combined with component-based normalization, which estimates scatter components with a dual energy acquisition using a convolution subtraction-method for an estimation of trues from an upper energy window. In order to reduce statistical noise in sinograms, the implemented scheme uses the DOI compression (DOIC) method, that combines deep pairs of DOI layers into the nearest shallow pairs of DOI layers with natural detector samplings. Since the compressed data preserve the block detector configuration, as if the data are acquired using 'virtual' detectors with high {gamma}-ray stopping power, these correction methods can be applied directly to DOIC sinograms. The proposed method provides high-quality corrected images with low statistical noise, even for a multi-layer DOI-PET.

Amygdala Contributions to Stimulus–Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning

Science.gov (United States)

Averbeck, Bruno B.

2017-01-01

Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus–reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus–reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus–reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus–reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus–reward associations. MFC also

Efficient Depth Enhancement Using a Combination of Color and Depth Information.

Science.gov (United States)

Lee, Kyungjae; Ban, Yuseok; Lee, Sangyoun

2017-07-01

Studies on depth images containing three-dimensional information have been performed for many practical applications. However, the depth images acquired from depth sensors have inherent problems, such as missing values and noisy boundaries. These problems significantly affect the performance of applications that use a depth image as their input. This paper describes a depth enhancement algorithm based on a combination of color and depth information. To fill depth holes and recover object shapes, asynchronous cellular automata with neighborhood distance maps are used. Image segmentation and a weighted linear combination of spatial filtering algorithms are applied to extract object regions and fill disocclusion in the object regions. Experimental results on both real-world and public datasets show that the proposed method enhances the quality of the depth image with low computational complexity, outperforming conventional methods on a number of metrics. Furthermore, to verify the performance of the proposed method, we present stereoscopic images generated by the enhanced depth image to illustrate the improvement in quality.

Flipped-Adversarial AutoEncoders

OpenAIRE

Zhang, Jiyi; Dang, Hung; Lee, Hwee Kuan; Chang, Ee-Chien

2018-01-01

We propose a flipped-Adversarial AutoEncoder (FAAE) that simultaneously trains a generative model G that maps an arbitrary latent code distribution to a data distribution and an encoder E that embodies an "inverse mapping" that encodes a data sample into a latent code vector. Unlike previous hybrid approaches that leverage adversarial training criterion in constructing autoencoders, FAAE minimizes re-encoding errors in the latent space and exploits adversarial criterion in the data space. Exp...

Action recognition in depth video from RGB perspective: A knowledge transfer manner

Science.gov (United States)

Chen, Jun; Xiao, Yang; Cao, Zhiguo; Fang, Zhiwen

2018-03-01

Different video modal for human action recognition has becoming a highly promising trend in the video analysis. In this paper, we propose a method for human action recognition from RGB video to Depth video using domain adaptation, where we use learned feature from RGB videos to do action recognition for depth videos. More specifically, we make three steps for solving this problem in this paper. First, different from image, video is more complex as it has both spatial and temporal information, in order to better encode this information, dynamic image method is used to represent each RGB or Depth video to one image, based on this, most methods for extracting feature in image can be used in video. Secondly, as video can be represented as image, so standard CNN model can be used for training and testing for videos, beside, CNN model can be also used for feature extracting as its powerful feature expressing ability. Thirdly, as RGB videos and Depth videos are belong to two different domains, in order to make two different feature domains has more similarity, domain adaptation is firstly used for solving this problem between RGB and Depth video, based on this, the learned feature from RGB video model can be directly used for Depth video classification. We evaluate the proposed method on one complex RGB-D action dataset (NTU RGB-D), and our method can have more than 2% accuracy improvement using domain adaptation from RGB to Depth action recognition.

Focused fluorescence excitation with time-reversed ultrasonically encoded light and imaging in thick scattering media

International Nuclear Information System (INIS)

Lai, Puxiang; Suzuki, Yuta; Xu, Xiao; Wang, Lihong V

2013-01-01

Scattering dominates light propagation in biological tissue, and therefore restricts both resolution and penetration depth in optical imaging within thick tissue. As photons travel into the diffusive regime, typically 1 mm beneath human skin, their trajectories transition from ballistic to diffusive due to the increased number of scattering events, which makes it impossible to focus, much less track, photon paths. Consequently, imaging methods that rely on controlled light illumination are ineffective in deep tissue. This problem has recently been addressed by a novel method capable of dynamically focusing light in thick scattering media via time reversal of ultrasonically encoded (TRUE) diffused light. Here, using photorefractive materials as phase conjugate mirrors, we show a direct visualization and dynamic control of optical focusing with this light delivery method, and demonstrate its application for focused fluorescence excitation and imaging in thick turbid media. These abilities are increasingly critical for understanding the dynamic interactions of light with biological matter and processes at different system levels, as well as their applications for biomedical diagnosis and therapy. (letter)

Quantum engineering of continuous variable quantum states

Energy Technology Data Exchange (ETDEWEB)

Sabuncu, Metin

2009-10-29

Quantum information with continuous variables is a field attracting increasing attention recently. In continuous variable quantum information one makes use of the continuous information encoded into the quadrature of a quantized light field instead of binary quantities such as the polarization state of a single photon. This brand new research area is witnessing exciting theoretical and experimental achievements such as teleportation, quantum computation and quantum error correction. The rapid development of the field is mainly due higher optical data rates and the availability of simple and efficient manipulation tools in continuous-variable quantum information processing. We in this thesis extend the work in continuous variable quantum information processing and report on novel experiments on amplification, cloning, minimal disturbance and noise erasure protocols. The promising results we obtain in these pioneering experiments indicate that the future of continuous variable quantum information is bright and many advances can be foreseen. (orig.)

Quantum engineering of continuous variable quantum states

International Nuclear Information System (INIS)

Sabuncu, Metin

2009-01-01

Quantum information with continuous variables is a field attracting increasing attention recently. In continuous variable quantum information one makes use of the continuous information encoded into the quadrature of a quantized light field instead of binary quantities such as the polarization state of a single photon. This brand new research area is witnessing exciting theoretical and experimental achievements such as teleportation, quantum computation and quantum error correction. The rapid development of the field is mainly due higher optical data rates and the availability of simple and efficient manipulation tools in continuous-variable quantum information processing. We in this thesis extend the work in continuous variable quantum information processing and report on novel experiments on amplification, cloning, minimal disturbance and noise erasure protocols. The promising results we obtain in these pioneering experiments indicate that the future of continuous variable quantum information is bright and many advances can be foreseen. (orig.)

Sensitivity and specificity considerations for fMRI encoding, decoding, and mapping of auditory cortex at ultra-high field.

Science.gov (United States)

Moerel, Michelle; De Martino, Federico; Kemper, Valentin G; Schmitter, Sebastian; Vu, An T; Uğurbil, Kâmil; Formisano, Elia; Yacoub, Essa

2018-01-01

Following rapid technological advances, ultra-high field functional MRI (fMRI) enables exploring correlates of neuronal population activity at an increasing spatial resolution. However, as the fMRI blood-oxygenation-level-dependent (BOLD) contrast is a vascular signal, the spatial specificity of fMRI data is ultimately determined by the characteristics of the underlying vasculature. At 7T, fMRI measurement parameters determine the relative contribution of the macro- and microvasculature to the acquired signal. Here we investigate how these parameters affect relevant high-end fMRI analyses such as encoding, decoding, and submillimeter mapping of voxel preferences in the human auditory cortex. Specifically, we compare a T 2 * weighted fMRI dataset, obtained with 2D gradient echo (GE) EPI, to a predominantly T 2 weighted dataset obtained with 3D GRASE. We first investigated the decoding accuracy based on two encoding models that represented different hypotheses about auditory cortical processing. This encoding/decoding analysis profited from the large spatial coverage and sensitivity of the T 2 * weighted acquisitions, as evidenced by a significantly higher prediction accuracy in the GE-EPI dataset compared to the 3D GRASE dataset for both encoding models. The main disadvantage of the T 2 * weighted GE-EPI dataset for encoding/decoding analyses was that the prediction accuracy exhibited cortical depth dependent vascular biases. However, we propose that the comparison of prediction accuracy across the different encoding models may be used as a post processing technique to salvage the spatial interpretability of the GE-EPI cortical depth-dependent prediction accuracy. Second, we explored the mapping of voxel preferences. Large-scale maps of frequency preference (i.e., tonotopy) were similar across datasets, yet the GE-EPI dataset was preferable due to its larger spatial coverage and sensitivity. However, submillimeter tonotopy maps revealed biases in assigned frequency

Depth resolution and preferential sputtering in depth profiling of sharp interfaces

International Nuclear Information System (INIS)

Hofmann, S.; Han, Y.S.; Wang, J.Y.

2017-01-01

Highlights: • Interfacial depth resolution from MRI model depends on sputtering rate differences. • Depth resolution critically depends on the dominance of roughness or atomic mixing. • True (depth scale) and apparent (time scale) depth resolutions are different. • Average sputtering rate approximately yields true from apparent depth resolution. • Profiles by SIMS and XPS are different but similar to surface concentrations. - Abstract: The influence of preferential sputtering on depth resolution of sputter depth profiles is studied for different sputtering rates of the two components at an A/B interface. Surface concentration and intensity depth profiles on both the sputtering time scale (as measured) and the depth scale are obtained by calculations with an extended Mixing-Roughness-Information depth (MRI)-model. The results show a clear difference for the two extreme cases (a) preponderant roughness and (b) preponderant atomic mixing. In case (a), the interface width on the time scale (Δt(16–84%)) increases with preferential sputtering if the faster sputtering component is on top of the slower sputtering component, but the true resolution on the depth scale (Δz(16–84%)) stays constant. In case (b), the interface width on the time scale stays constant but the true resolution on the depth scale varies with preferential sputtering. For similar order of magnitude of the atomic mixing and the roughness parameters, a transition state between the two extremes is obtained. While the normalized intensity profile of SIMS represents that of the surface concentration, an additional broadening effect is encountered in XPS or AES by the influence of the mean electron escape depth which may even cause an additional matrix effect at the interface.

Depth resolution and preferential sputtering in depth profiling of sharp interfaces

Energy Technology Data Exchange (ETDEWEB)

Hofmann, S. [Max Planck Institute for Intelligent Systems (formerly MPI for Metals Research), Heisenbergstrasse 3, D-70569 Stuttgart (Germany); Han, Y.S. [Department of Physics, Shantou University, 243 Daxue Road, Shantou, 515063 Guangdong (China); Wang, J.Y., E-mail: wangjy@stu.edu.cn [Department of Physics, Shantou University, 243 Daxue Road, Shantou, 515063 Guangdong (China)

2017-07-15

Highlights: • Interfacial depth resolution from MRI model depends on sputtering rate differences. • Depth resolution critically depends on the dominance of roughness or atomic mixing. • True (depth scale) and apparent (time scale) depth resolutions are different. • Average sputtering rate approximately yields true from apparent depth resolution. • Profiles by SIMS and XPS are different but similar to surface concentrations. - Abstract: The influence of preferential sputtering on depth resolution of sputter depth profiles is studied for different sputtering rates of the two components at an A/B interface. Surface concentration and intensity depth profiles on both the sputtering time scale (as measured) and the depth scale are obtained by calculations with an extended Mixing-Roughness-Information depth (MRI)-model. The results show a clear difference for the two extreme cases (a) preponderant roughness and (b) preponderant atomic mixing. In case (a), the interface width on the time scale (Δt(16–84%)) increases with preferential sputtering if the faster sputtering component is on top of the slower sputtering component, but the true resolution on the depth scale (Δz(16–84%)) stays constant. In case (b), the interface width on the time scale stays constant but the true resolution on the depth scale varies with preferential sputtering. For similar order of magnitude of the atomic mixing and the roughness parameters, a transition state between the two extremes is obtained. While the normalized intensity profile of SIMS represents that of the surface concentration, an additional broadening effect is encountered in XPS or AES by the influence of the mean electron escape depth which may even cause an additional matrix effect at the interface.

Episodic Memory Encoding Interferes with Reward Learning and Decreases Striatal Prediction Errors

Science.gov (United States)

Braun, Erin Kendall; Daw, Nathaniel D.

2014-01-01

Learning is essential for adaptive decision making. The striatum and its dopaminergic inputs are known to support incremental reward-based learning, while the hippocampus is known to support encoding of single events (episodic memory). Although traditionally studied separately, in even simple experiences, these two types of learning are likely to co-occur and may interact. Here we sought to understand the nature of this interaction by examining how incremental reward learning is related to concurrent episodic memory encoding. During the experiment, human participants made choices between two options (colored squares), each associated with a drifting probability of reward, with the goal of earning as much money as possible. Incidental, trial-unique object pictures, unrelated to the choice, were overlaid on each option. The next day, participants were given a surprise memory test for these pictures. We found that better episodic memory was related to a decreased influence of recent reward experience on choice, both within and across participants. fMRI analyses further revealed that during learning the canonical striatal reward prediction error signal was significantly weaker when episodic memory was stronger. This decrease in reward prediction error signals in the striatum was associated with enhanced functional connectivity between the hippocampus and striatum at the time of choice. Our results suggest a mechanism by which memory encoding may compete for striatal processing and provide insight into how interactions between different forms of learning guide reward-based decision making. PMID:25378157

Deconstructing continuous flash suppression

OpenAIRE

Yang, Eunice; Blake, Randolph

2012-01-01

In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in co...

Reducing depth induced spherical aberration in 3D widefield fluorescence microscopy by wavefront coding using the SQUBIC phase mask

Science.gov (United States)

Patwary, Nurmohammed; Doblas, Ana; King, Sharon V.; Preza, Chrysanthe

2014-03-01

Imaging thick biological samples introduces spherical aberration (SA) due to refractive index (RI) mismatch between specimen and imaging lens immersion medium. SA increases with the increase of either depth or RI mismatch. Therefore, it is difficult to find a static compensator for SA1. Different wavefront coding methods2,3 have been studied to find an optimal way of static wavefront correction to reduce depth-induced SA. Inspired by a recent design of a radially symmetric squared cubic (SQUBIC) phase mask that was tested for scanning confocal microscopy1 we have modified the pupil using the SQUBIC mask to engineer the point spread function (PSF) of a wide field fluorescence microscope. In this study, simulated images of a thick test object were generated using a wavefront encoded engineered PSF (WFEPSF) and were restored using space-invariant (SI) and depth-variant (DV) expectation maximization (EM) algorithms implemented in the COSMOS software4. Quantitative comparisons between restorations obtained with both the conventional and WFE PSFs are presented. Simulations show that, in the presence of SA, the use of the SIEM algorithm and a single SQUBIC encoded WFE-PSF can yield adequate image restoration. In addition, in the presence of a large amount of SA, it is possible to get adequate results using the DVEM with fewer DV-PSFs than would typically be required for processing images acquired with a clear circular aperture (CCA) PSF. This result implies that modification of a widefield system with the SQUBIC mask renders the system less sensitive to depth-induced SA and suitable for imaging samples at larger optical depths.

Continuous-variable quantum erasure correcting code

DEFF Research Database (Denmark)

Lassen, Mikael Østergaard; Sabuncu, Metin; Huck, Alexander

2010-01-01

We experimentally demonstrate a continuous variable quantum erasure-correcting code, which protects coherent states of light against complete erasure. The scheme encodes two coherent states into a bi-party entangled state, and the resulting 4-mode code is conveyed through 4 independent channels...

Dynamic Information Encoding With Dynamic Synapses in Neural Adaptation

Science.gov (United States)

Li, Luozheng; Mi, Yuanyuan; Zhang, Wenhao; Wang, Da-Hui; Wu, Si

2018-01-01

Adaptation refers to the general phenomenon that the neural system dynamically adjusts its response property according to the statistics of external inputs. In response to an invariant stimulation, neuronal firing rates first increase dramatically and then decrease gradually to a low level close to the background activity. This prompts a question: during the adaptation, how does the neural system encode the repeated stimulation with attenuated firing rates? It has been suggested that the neural system may employ a dynamical encoding strategy during the adaptation, the information of stimulus is mainly encoded by the strong independent spiking of neurons at the early stage of the adaptation; while the weak but synchronized activity of neurons encodes the stimulus information at the later stage of the adaptation. The previous study demonstrated that short-term facilitation (STF) of electrical synapses, which increases the synchronization between neurons, can provide a mechanism to realize dynamical encoding. In the present study, we further explore whether short-term plasticity (STP) of chemical synapses, an interaction form more common than electrical synapse in the cortex, can support dynamical encoding. We build a large-size network with chemical synapses between neurons. Notably, facilitation of chemical synapses only enhances pair-wise correlations between neurons mildly, but its effect on increasing synchronization of the network can be significant, and hence it can serve as a mechanism to convey the stimulus information. To read-out the stimulus information, we consider that a downstream neuron receives balanced excitatory and inhibitory inputs from the network, so that the downstream neuron only responds to synchronized firings of the network. Therefore, the response of the downstream neuron indicates the presence of the repeated stimulation. Overall, our study demonstrates that STP of chemical synapse can serve as a mechanism to realize dynamical neural

Automatic semantic encoding in verbal short-term memory: evidence from the concreteness effect.

Science.gov (United States)

Campoy, Guillermo; Castellà, Judit; Provencio, Violeta; Hitch, Graham J; Baddeley, Alan D

2015-01-01

The concreteness effect in verbal short-term memory (STM) tasks is assumed to be a consequence of semantic encoding in STM, with immediate recall of concrete words benefiting from richer semantic representations. We used the concreteness effect to test the hypothesis that semantic encoding in standard verbal STM tasks is a consequence of controlled, attention-demanding mechanisms of strategic semantic retrieval and encoding. Experiment 1 analysed the effect of presentation rate, with slow presentations being assumed to benefit strategic, time-dependent semantic encoding. Experiments 2 and 3 provided a more direct test of the strategic hypothesis by introducing three different concurrent attention-demanding tasks. Although Experiment 1 showed a larger concreteness effect with slow presentations, the following two experiments yielded strong evidence against the strategic hypothesis. Limiting available attention resources by concurrent tasks reduced global memory performance, but the concreteness effect was equivalent to that found in control conditions. We conclude that semantic effects in STM result from automatic semantic encoding and provide tentative explanations for the interaction between the concreteness effect and the presentation rate.

Emotional Encoding Context Leads to Memory Bias in Individuals with High Anxiety.

Science.gov (United States)

Lee, Christopher; Fernandes, Myra A

2017-12-27

We investigated whether anxious individuals, who adopt an inherently negative mindset, demonstrate a particularly salient memory bias for words tainted by negative contexts. To this end, sequentially presented target words, overlayed onto negative or neutral pictures, were studied in separate blocks (within-subjects) using a deep or shallow encoding instruction (between-subjects). Following study, in Test 1, participants completed separate recognition test blocks for the words overlayed onto the negative and the neutral contexts. Following this, in Test 2, participants completed a recognition test for the foils from each Test 1 block. We found a significant three-way interaction on Test 2, such that individuals with high anxiety who initially studied target words using a shallow encoding instruction, demonstrated significantly elevated memory for foils that were contained within the negative Test 1 block. Results show that during retrieval (Test 1), participants re-entered the mode of processing (negative or neutral) engaged at encoding, tainting the encoding of foils with that same mode of processing. The findings suggest that individuals with high relative to low anxiety, adopt a particularly salient negative retrieval mode, and this creates a downstream bias in encoding and subsequent retrieval of otherwise neutral information.

Using spatial manipulation to examine interactions between visual and auditory encoding of pitch and time

Directory of Open Access Journals (Sweden)

Neil M McLachlan

2010-12-01

Full Text Available Music notations use both symbolic and spatial representation systems. Novice musicians do not have the training to associate symbolic information with musical identities, such as chords or rhythmic and melodic patterns. They provide an opportunity to explore the mechanisms underpinning multimodal learning when spatial encoding strategies of feature dimensions might be expected to dominate. In this study, we applied a range of transformations (such as time reversal to short melodies and rhythms and asked novice musicians to identify them with or without the aid of notation. Performance using a purely spatial (graphic notation was contrasted with the more symbolic, traditional western notation over a series of weekly sessions. The results showed learning effects for both notation types, but performance improved more for graphic notation. This points to greater compatibility of auditory and visual neural codes for novice musicians when using spatial notation, suggesting that pitch and time may be spatially encoded in multimodal associative memory. The findings also point to new strategies for training novice musicians.

Selecting Operations for Assembler Encoding

Directory of Open Access Journals (Sweden)

Tomasz Praczyk

2010-04-01

Full Text Available Assembler Encoding is a neuro-evolutionary method in which a neural network is represented in the form of a simple program called Assembler Encoding Program. The task of the program is to create the so-called Network Definition Matrix which maintains all the information necessary to construct the network. To generate Assembler Encoding Programs and the subsequent neural networks evolutionary techniques are used.
The performance of Assembler Encoding strongly depends on operations used in Assembler Encoding Programs. To select the most effective operations, experiments in the optimization and the predator-prey problem were carried out. In the experiments, Assembler Encoding Programs equipped with different types of operations were tested. The results of the tests are presented at the end of the paper.

An Intensional Concurrent Faithful Encoding of Turing Machines

Directory of Open Access Journals (Sweden)

Thomas Given-Wilson

2014-10-01

Full Text Available The benchmark for computation is typically given as Turing computability; the ability for a computation to be performed by a Turing Machine. Many languages exploit (indirect encodings of Turing Machines to demonstrate their ability to support arbitrary computation. However, these encodings are usually by simulating the entire Turing Machine within the language, or by encoding a language that does an encoding or simulation itself. This second category is typical for process calculi that show an encoding of lambda-calculus (often with restrictions that in turn simulates a Turing Machine. Such approaches lead to indirect encodings of Turing Machines that are complex, unclear, and only weakly equivalent after computation. This paper presents an approach to encoding Turing Machines into intensional process calculi that is faithful, reduction preserving, and structurally equivalent. The encoding is demonstrated in a simple asymmetric concurrent pattern calculus before generalised to simplify infinite terms, and to show encodings into Concurrent Pattern Calculus and Psi Calculi.

Downstream processing from melt granulation towards tablets: In-depth analysis of a continuous twin-screw melt granulation process using polymeric binders.

Science.gov (United States)

Grymonpré, W; Verstraete, G; Vanhoorne, V; Remon, J P; De Beer, T; Vervaet, C

2018-03-01

The concept of twin-screw melt granulation (TSMG) has steadily (re)-gained interest in pharmaceutical formulation development as an intermediate step during tablet manufacturing. However, to be considered as a viable processing option for solid oral dosage forms there is a need to understand all critical sources of variability which could affect this granulation technique. The purpose of this study was to provide an in-depth analysis of the continuous TSMG process in order to expose the critical process parameters (CPP) and elucidate the impact of process and formulation parameters on the critical quality attributes (CQA) of granules and tablets during continuous TSMG. A first part of the study dealt with the screening of various amorphous polymers as binder for producing high-dosed melt granules of two model drug (i.e. acetaminophen and hydrochlorothiazide). The second part of this study described a quality-by-design (QbD) approach for melt granulation of hydrochlorothiazide in order to thoroughly evaluate TSMG, milling and tableting stage of the continuous TSMG line. Using amorphous polymeric binders resulted in melt granules with high milling efficiency due to their brittle behaviour without producing excessive amounts of fines, providing high granule yields with low friability. Therefore, it makes them extremely suitable for further downstream processing. One of the most important CPP during TSMG with polymeric binders was the granulation-torque, which - in case of polymers with high T g - increased during longer granulation runs to critical levels endangering the continuous process flow. However, by optimizing both screw speed and throughput or changing to polymeric binders with lower T g it was possible to significantly reduce this risk. This research paper highlighted that TSMG must be considered as a viable option during formulation development of solid oral dosage forms based on the robustness of the CQA of both melt granules and tablets. Copyright © 2017

Exhaustive search of linear information encoding protein-peptide recognition.

Science.gov (United States)

Kelil, Abdellali; Dubreuil, Benjamin; Levy, Emmanuel D; Michnick, Stephen W

2017-04-01

High-throughput in vitro methods have been extensively applied to identify linear information that encodes peptide recognition. However, these methods are limited in number of peptides, sequence variation, and length of peptides that can be explored, and often produce solutions that are not found in the cell. Despite the large number of methods developed to attempt addressing these issues, the exhaustive search of linear information encoding protein-peptide recognition has been so far physically unfeasible. Here, we describe a strategy, called DALEL, for the exhaustive search of linear sequence information encoded in proteins that bind to a common partner. We applied DALEL to explore binding specificity of SH3 domains in the budding yeast Saccharomyces cerevisiae. Using only the polypeptide sequences of SH3 domain binding proteins, we succeeded in identifying the majority of known SH3 binding sites previously discovered either in vitro or in vivo. Moreover, we discovered a number of sites with both non-canonical sequences and distinct properties that may serve ancillary roles in peptide recognition. We compared DALEL to a variety of state-of-the-art algorithms in the blind identification of known binding sites of the human Grb2 SH3 domain. We also benchmarked DALEL on curated biological motifs derived from the ELM database to evaluate the effect of increasing/decreasing the enrichment of the motifs. Our strategy can be applied in conjunction with experimental data of proteins interacting with a common partner to identify binding sites among them. Yet, our strategy can also be applied to any group of proteins of interest to identify enriched linear motifs or to exhaustively explore the space of linear information encoded in a polypeptide sequence. Finally, we have developed a webserver located at http://michnick.bcm.umontreal.ca/dalel, offering user-friendly interface and providing different scenarios utilizing DALEL.

Depth of Cure of New Flowable Composite Resins

Science.gov (United States)

2012-03-30

we met. His encouragement and undiminished love for the past 20 years has been my motivation. This thesis is also dedicated to my four children ...assessed to be the most commonly used by dentists. Therefore, the depths of cure data from this study are pertinent to the practice of dentistry ...Continuing Education in Dentistry . Http://cde.dentalaegis.com Dai Q, Bertrand S. Wear resistance of Surefil SDR Flow posterior flowable base. JDR

Spacetime replication of continuous variable quantum information

International Nuclear Information System (INIS)

Hayden, Patrick; Nezami, Sepehr; Salton, Grant; Sanders, Barry C

2016-01-01

The theory of relativity requires that no information travel faster than light, whereas the unitarity of quantum mechanics ensures that quantum information cannot be cloned. These conditions provide the basic constraints that appear in information replication tasks, which formalize aspects of the behavior of information in relativistic quantum mechanics. In this article, we provide continuous variable (CV) strategies for spacetime quantum information replication that are directly amenable to optical or mechanical implementation. We use a new class of homologically constructed CV quantum error correcting codes to provide efficient solutions for the general case of information replication. As compared to schemes encoding qubits, our CV solution requires half as many shares per encoded system. We also provide an optimized five-mode strategy for replicating quantum information in a particular configuration of four spacetime regions designed not to be reducible to previously performed experiments. For this optimized strategy, we provide detailed encoding and decoding procedures using standard optical apparatus and calculate the recovery fidelity when finite squeezing is used. As such we provide a scheme for experimentally realizing quantum information replication using quantum optics. (paper)

Vega-Lite: A Grammar of Interactive Graphics.

Science.gov (United States)

Satyanarayan, Arvind; Moritz, Dominik; Wongsuphasawat, Kanit; Heer, Jeffrey

2017-01-01

We present Vega-Lite, a high-level grammar that enables rapid specification of interactive data visualizations. Vega-Lite combines a traditional grammar of graphics, providing visual encoding rules and a composition algebra for layered and multi-view displays, with a novel grammar of interaction. Users specify interactive semantics by composing selections. In Vega-Lite, a selection is an abstraction that defines input event processing, points of interest, and a predicate function for inclusion testing. Selections parameterize visual encodings by serving as input data, defining scale extents, or by driving conditional logic. The Vega-Lite compiler automatically synthesizes requisite data flow and event handling logic, which users can override for further customization. In contrast to existing reactive specifications, Vega-Lite selections decompose an interaction design into concise, enumerable semantic units. We evaluate Vega-Lite through a range of examples, demonstrating succinct specification of both customized interaction methods and common techniques such as panning, zooming, and linked selection.

Universal quantum entanglement between an oscillator and continuous fields

International Nuclear Information System (INIS)

Miao Haixing; Danilishin, Stefan; Chen Yanbei

2010-01-01

Quantum entanglement has been actively sought in optomechanical and electromechanical systems. The simplest system is a mechanical oscillator interacting with a coherent optical field, while the oscillator also suffers from thermal decoherence. With a rigorous functional analysis, we develop a mathematical framework for treating quantum entanglement that involves infinite degrees of freedom. We show that the quantum entanglement is always present between the oscillator and continuous optical field--even when the environmental temperature is high and the oscillator is highly classical. Such a universal entanglement is also shown to be able to survive more than one mechanical oscillation period if the characteristic frequency of the optomechanical interaction is larger than that of the thermal noise. In addition, we introduce effective optical modes that are ordered by the entanglement strength to better understand the entanglement structure, analogously to the energy spectrum of an atomic system. In particular, we derive the optical mode that is maximally entangled with the mechanical oscillator, which will be useful for future quantum computing and encoding information into mechanical degrees of freedom.

Depth-of-interaction estimates in pixelated scintillator sensors using Monte Carlo techniques

International Nuclear Information System (INIS)

Sharma, Diksha; Sze, Christina; Bhandari, Harish; Nagarkar, Vivek; Badano, Aldo

2017-01-01

Image quality in thick scintillator detectors can be improved by minimizing parallax errors through depth-of-interaction (DOI) estimation. A novel sensor for low-energy single photon imaging having a thick, transparent, crystalline pixelated micro-columnar CsI:Tl scintillator structure has been described, with possible future application in small-animal single photon emission computed tomography (SPECT) imaging when using thicker structures under development. In order to understand the fundamental limits of this new structure, we introduce cartesianDETECT2, an open-source optical transport package that uses Monte Carlo methods to obtain estimates of DOI for improving spatial resolution of nuclear imaging applications. Optical photon paths are calculated as a function of varying simulation parameters such as columnar surface roughness, bulk, and top-surface absorption. We use scanning electron microscope images to estimate appropriate surface roughness coefficients. Simulation results are analyzed to model and establish patterns between DOI and photon scattering. The effect of varying starting locations of optical photons on the spatial response is studied. Bulk and top-surface absorption fractions were varied to investigate their effect on spatial response as a function of DOI. We investigated the accuracy of our DOI estimation model for a particular screen with various training and testing sets, and for all cases the percent error between the estimated and actual DOI over the majority of the detector thickness was ±5% with a maximum error of up to ±10% at deeper DOIs. In addition, we found that cartesianDETECT2 is computationally five times more efficient than MANTIS. Findings indicate that DOI estimates can be extracted from a double-Gaussian model of the detector response. We observed that our model predicts DOI in pixelated scintillator detectors reasonably well.

Holovideo: Real-time 3D range video encoding and decoding on GPU

Science.gov (United States)

Karpinsky, Nikolaus; Zhang, Song

2012-02-01

We present a 3D video-encoding technique called Holovideo that is capable of encoding high-resolution 3D videos into standard 2D videos, and then decoding the 2D videos back into 3D rapidly without significant loss of quality. Due to the nature of the algorithm, 2D video compression such as JPEG encoding with QuickTime Run Length Encoding (QTRLE) can be applied with little quality loss, resulting in an effective way to store 3D video at very small file sizes. We found that under a compression ratio of 134:1, Holovideo to OBJ file format, the 3D geometry quality drops at a negligible level. Several sets of 3D videos were captured using a structured light scanner, compressed using the Holovideo codec, and then uncompressed and displayed to demonstrate the effectiveness of the codec. With the use of OpenGL Shaders (GLSL), the 3D video codec can encode and decode in realtime. We demonstrated that for a video size of 512×512, the decoding speed is 28 frames per second (FPS) with a laptop computer using an embedded NVIDIA GeForce 9400 m graphics processing unit (GPU). Encoding can be done with this same setup at 18 FPS, making this technology suitable for applications such as interactive 3D video games and 3D video conferencing.

A continuous OSL scanning method for analysis of radiation depth-dose profiles in bricks

DEFF Research Database (Denmark)

Bøtter-Jensen, L.; Jungner, H.; Poolton, N.R.J.

1995-01-01

This article describes the development of a method for directly measuring radiation depth-dose profiles from brick, tile and porcelain cores, without the need for sample separation techniques. For the brick cores, examples are shown of the profiles generated by artificial irradiation using...... the different photon energies from Cs-137 and Co-60 gamma sources; comparison is drawn with both the theoretical calculations derived from Monte Carlo simulations, as well as experimental measurements made using more conventional optically stimulated luminescence methods of analysis....

Facial expression recognition based on improved local ternary pattern and stacked auto-encoder

Science.gov (United States)

Wu, Yao; Qiu, Weigen

2017-08-01

In order to enhance the robustness of facial expression recognition, we propose a method of facial expression recognition based on improved Local Ternary Pattern (LTP) combined with Stacked Auto-Encoder (SAE). This method uses the improved LTP extraction feature, and then uses the improved depth belief network as the detector and classifier to extract the LTP feature. The combination of LTP and improved deep belief network is realized in facial expression recognition. The recognition rate on CK+ databases has improved significantly.

The deconvolution of sputter-etching surface concentration measurements to determine impurity depth profiles

International Nuclear Information System (INIS)

Carter, G.; Katardjiev, I.V.; Nobes, M.J.

1989-01-01

The quasi-linear partial differential continuity equations that describe the evolution of the depth profiles and surface concentrations of marker atoms in kinematically equivalent systems undergoing sputtering, ion collection and atomic mixing are solved using the method of characteristics. It is shown how atomic mixing probabilities can be deduced from measurements of ion collection depth profiles with increasing ion fluence, and how this information can be used to predict surface concentration evolution. Even with this information, however, it is shown that it is not possible to deconvolute directly the surface concentration measurements to provide initial depth profiles, except when only ion collection and sputtering from the surface layer alone occur. It is demonstrated further that optimal recovery of initial concentration depth profiles could be ensured if the concentration-measuring analytical probe preferentially sampled depths near and at the maximum depth of bombardment-induced perturbations. (author)

Network Physiology: How Organ Systems Dynamically Interact

Science.gov (United States)

Bartsch, Ronny P.; Liu, Kang K. L.; Bashan, Amir; Ivanov, Plamen Ch.

2015-01-01

We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems. PMID:26555073

Network Physiology: How Organ Systems Dynamically Interact.

Science.gov (United States)

Bartsch, Ronny P; Liu, Kang K L; Bashan, Amir; Ivanov, Plamen Ch

2015-01-01

We systematically study how diverse physiologic systems in the human organism dynamically interact and collectively behave to produce distinct physiologic states and functions. This is a fundamental question in the new interdisciplinary field of Network Physiology, and has not been previously explored. Introducing the novel concept of Time Delay Stability (TDS), we develop a computational approach to identify and quantify networks of physiologic interactions from long-term continuous, multi-channel physiological recordings. We also develop a physiologically-motivated visualization framework to map networks of dynamical organ interactions to graphical objects encoded with information about the coupling strength of network links quantified using the TDS measure. Applying a system-wide integrative approach, we identify distinct patterns in the network structure of organ interactions, as well as the frequency bands through which these interactions are mediated. We establish first maps representing physiologic organ network interactions and discover basic rules underlying the complex hierarchical reorganization in physiologic networks with transitions across physiologic states. Our findings demonstrate a direct association between network topology and physiologic function, and provide new insights into understanding how health and distinct physiologic states emerge from networked interactions among nonlinear multi-component complex systems. The presented here investigations are initial steps in building a first atlas of dynamic interactions among organ systems.

An Exploration of the Needling Depth in Acupuncture: The Safe Needling Depth and the Needling Depth of Clinical Efficacy

Directory of Open Access Journals (Sweden)

Jaung-Geng Lin

2013-01-01

Full Text Available Objective. To explore the existing scientific information regarding safe needling depth of acupuncture points and the needling depth of clinical efficacy. Methods. We searched the PubMed, EMBASE, Cochrane, Allied and Complementary Medicine (AMED, The National Center for Complementary and Alternative Medicine (NCCAM, and China National Knowledge Infrastructure (CNKI databases to identify relevant monographs and related references from 1991 to 2013. Chinese journals and theses/dissertations were hand searched. Results. 47 studies were recruited and divided into 6 groups by measuring tools, that is, MRI, in vivo evaluation, CT, ultrasound, dissected specimen of cadavers, and another group with clinical efficacy. Each research was analyzed for study design, definition of safe depth, and factors that would affect the measured depths. Depths of clinical efficacy were discussed from the perspective of de-qi and other clinical observations. Conclusions. Great inconsistency in depth of each point measured from different subject groups and tools exists. The definition of safe depth should be established through standardization. There is also lack of researches to compare the clinical efficacy. A well-designed clinical trial selecting proper measuring tools to decide the actual and advisable needling depth for each point, to avoid adverse effects or complications and promote optimal clinical efficacy, is a top priority.

Age-related influences of prior sleep on brain activation during verbal encoding

Directory of Open Access Journals (Sweden)

Michelle B Jonelis

2012-04-01

Full Text Available Disrupted sleep is more common in older adults (OA than younger adults (YA, often co-morbid with other conditions. How these sleep disturbances affect cognitive performance is an area of active study. We examined whether brain activation during verbal encoding correlates with sleep quantity and quality the night before testing in a group of healthy OA and YA. Twenty-seven OA (ages 59-82 and twenty-seven YA (ages 19-36 underwent one night of standard polysomnography. Twelve hours post-awakening, subjects performed a verbal encoding task while undergoing functional MRI. Analyses examined the group (OA vs. YA by prior sleep quantity (Total Sleep Time (TST or quality (Sleep Efficiency (SE interaction on cerebral activation, controlling for performance. Longer TST promoted higher levels of activation in the bilateral anterior parahippocampi in OA and lower activation levels in the left anterior parahippocampus in YA. Greater SE promoted higher activation levels in the left posterior parahippocampus and right inferior frontal gyrus in YA, but not in OA. The roles of these brain regions in verbal encoding suggest, in OA, longer sleep duration may facilitate functional compensation during cognitive challenges. By contrast, in YA, shorter sleep duration may necessitate functional compensation to maintain cognitive performance, similar to what is seen following acute sleep deprivation. Additionally, in YA, better sleep quality may improve semantic retrieval processes, thereby aiding encoding.

Prospective memory function in late adulthood: affect at encoding and resource allocation costs.

Directory of Open Access Journals (Sweden)

Julie D Henry

Full Text Available Some studies have found that prospective memory (PM cues which are emotionally valenced influence age effects in prospective remembering, but it remains unclear whether this effect reflects the operation of processes implemented at encoding or retrieval. In addition, none of the prior ageing studies of valence on PM function have examined potential costs of engaging in different valence conditions, or resource allocation trade-offs between the PM and the ongoing task. In the present study, younger, young-old and old-old adults completed a PM task in which the valence of the cues varied systematically (positive, negative or neutral at encoding, but was kept constant (neutral at retrieval. The results indicated that PM accuracy did not vary as a function of affect at encoding, and that this effect did not interact with age group. There was also no main or interaction effect of valence on PM reaction time in PM cue trials, indicating that valence costs across the three encoding conditions were equivalent. Old-old adults' PM accuracy was reduced relative to both young-old and younger adults. Prospective remembering incurred dual-task costs for all three groups. Analyses of reaction time data suggested that for both young-old and old-old, these costs were greater, implying differential resource allocation cost trade-offs. However, when reaction time data were expressed as a proportional change that adjusted for the general slowing of the older adults, costs did not differ as a function of group.

Prototype development or multi-cavity ion chamber for depth dose measurement

International Nuclear Information System (INIS)

Nayak, M.K.; Sahu, T.K.; Haridas, G.; Bandyopadhyay, Tapas; Tripathi, R.M.; Nandedkar, R.V.

2016-01-01

In high energy electron accelerators, when the electrons interact with vacuum chamber or surrounding structural material, Bremsstrahlung x-rays are produced. It is having a broad spectrum extending up to the electron energies. Dose measured as a function of depth due to electromagnetic cascade will give rise to depth dose curve. To measure the online depth dose profile in an absorber medium, when high energy electron or Bremsstrahlung is incident, a prototype Multi-Cavity Ion Chamber (MCIC) detector is developed. The paper describes the design and development of the MCIC for measurement of depth dose profile

Wind profiler mixing depth and entrainment measurements with chemical applications

Energy Technology Data Exchange (ETDEWEB)

Angevine, W.M.; Trainer, M.; Parrish, D.D.; Buhr, M.P.; Fehsenfeld, F.C. [NOAA Aeronomy Lab., Boulder, CO (United States); Kok, G.L. [NCAR Research Aviation Facility, Boulder, CO (United States)

1994-12-31

Wind profiling radars operating at 915 MHz have been present at a number of regional air quality studies. The profilers can provide a continuous, accurate record of the depth of the convective mixed layer with good time resolution. Profilers also provide information about entrainment at the boundary layer top. Mixing depth data from several days of the Rural Oxidants in the Southern Environment II (ROSE II) study in Alabama in June, 1992 are presented. For several cases, chemical measurements from aircraft and ground-based instruments are shown to correspond to mixing depth and entrainment zone behavior observed by the profiler.

Episodic memory encoding interferes with reward learning and decreases striatal prediction errors.

Science.gov (United States)

Wimmer, G Elliott; Braun, Erin Kendall; Daw, Nathaniel D; Shohamy, Daphna

2014-11-05

Learning is essential for adaptive decision making. The striatum and its dopaminergic inputs are known to support incremental reward-based learning, while the hippocampus is known to support encoding of single events (episodic memory). Although traditionally studied separately, in even simple experiences, these two types of learning are likely to co-occur and may interact. Here we sought to understand the nature of this interaction by examining how incremental reward learning is related to concurrent episodic memory encoding. During the experiment, human participants made choices between two options (colored squares), each associated with a drifting probability of reward, with the goal of earning as much money as possible. Incidental, trial-unique object pictures, unrelated to the choice, were overlaid on each option. The next day, participants were given a surprise memory test for these pictures. We found that better episodic memory was related to a decreased influence of recent reward experience on choice, both within and across participants. fMRI analyses further revealed that during learning the canonical striatal reward prediction error signal was significantly weaker when episodic memory was stronger. This decrease in reward prediction error signals in the striatum was associated with enhanced functional connectivity between the hippocampus and striatum at the time of choice. Our results suggest a mechanism by which memory encoding may compete for striatal processing and provide insight into how interactions between different forms of learning guide reward-based decision making. Copyright © 2014 the authors 0270-6474/14/3414901-12$15.00/0.

Amygdala Contributions to Stimulus-Reward Encoding in the Macaque Medial and Orbital Frontal Cortex during Learning.

Science.gov (United States)

Rudebeck, Peter H; Ripple, Joshua A; Mitz, Andrew R; Averbeck, Bruno B; Murray, Elisabeth A

2017-02-22

Orbitofrontal cortex (OFC), medial frontal cortex (MFC), and amygdala mediate stimulus-reward learning, but the mechanisms through which they interact are unclear. Here, we investigated how neurons in macaque OFC and MFC signaled rewards and the stimuli that predicted them during learning with and without amygdala input. Macaques performed a task that required them to evaluate two stimuli and then choose one to receive the reward associated with that option. Four main findings emerged. First, amygdala lesions slowed the acquisition and use of stimulus-reward associations. Further analyses indicated that this impairment was due, at least in part, to ineffective use of negative feedback to guide subsequent decisions. Second, the activity of neurons in OFC and MFC rapidly evolved to encode the amount of reward associated with each stimulus. Third, amygdalectomy reduced encoding of stimulus-reward associations during the evaluation of different stimuli. Reward encoding of anticipated and received reward after choices were made was not altered. Fourth, amygdala lesions led to an increase in the proportion of neurons in MFC, but not OFC, that encoded the instrumental response that monkeys made on each trial. These correlated changes in behavior and neural activity after amygdala lesions strongly suggest that the amygdala contributes to the ability to learn stimulus-reward associations rapidly by shaping encoding within OFC and MFC. SIGNIFICANCE STATEMENT Altered functional interactions among orbital frontal cortex (OFC), medial frontal cortex (MFC), and amygdala are thought to underlie several psychiatric conditions, many related to reward learning. Here, we investigated the causal contribution of the amygdala to the development of neuronal activity in macaque OFC and MFC related to rewards and the stimuli that predict them during learning. Without amygdala inputs, neurons in both OFC and MFC showed decreased encoding of stimulus-reward associations. MFC also showed

Effects of emotion and reward motivation on neural correlates of episodic memory encoding: a PET study.

Science.gov (United States)

Shigemune, Yayoi; Abe, Nobuhito; Suzuki, Maki; Ueno, Aya; Mori, Etsuro; Tashiro, Manabu; Itoh, Masatoshi; Fujii, Toshikatsu

2010-05-01

It is known that emotion and reward motivation promote long-term memory formation. It remains unclear, however, how and where emotion and reward are integrated during episodic memory encoding. In the present study, subjects were engaged in intentional encoding of photographs under four different conditions that were made by combining two factors (emotional valence, negative or neutral; and monetary reward value, high or low for subsequent successful recognition) during H2 15O positron emission tomography (PET) scanning. As for recognition performance, we found significant main effects of emotional valence (negative>neutral) and reward value (high value>low value), without an interaction between the two factors. Imaging data showed that the left amygdala was activated during the encoding conditions of negative pictures relative to neutral pictures, and the left orbitofrontal cortex was activated during the encoding conditions of high reward pictures relative to low reward pictures. In addition, conjunction analysis of these two main effects detected right hippocampal activation. Although we could not find correlations between recognition performance and activity of these three regions, we speculate that the right hippocampus may integrate the effects of emotion (processed in the amygdala) and monetary reward (processed in the orbitofrontal cortex) on episodic memory encoding. 2010 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.

Chemical Space of DNA-Encoded Libraries.

Science.gov (United States)

Franzini, Raphael M; Randolph, Cassie

2016-07-28

In recent years, DNA-encoded chemical libraries (DECLs) have attracted considerable attention as a potential discovery tool in drug development. Screening encoded libraries may offer advantages over conventional hit discovery approaches and has the potential to complement such methods in pharmaceutical research. As a result of the increased application of encoded libraries in drug discovery, a growing number of hit compounds are emerging in scientific literature. In this review we evaluate reported encoded library-derived structures and identify general trends of these compounds in relation to library design parameters. We in particular emphasize the combinatorial nature of these libraries. Generally, the reported molecules demonstrate the ability of this technology to afford hits suitable for further lead development, and on the basis of them, we derive guidelines for DECL design.

Emotional Encoding Context Leads to Memory Bias in Individuals with High Anxiety

Directory of Open Access Journals (Sweden)

Christopher Lee

2017-12-01

Full Text Available We investigated whether anxious individuals, who adopt an inherently negative mindset, demonstrate a particularly salient memory bias for words tainted by negative contexts. To this end, sequentially presented target words, overlayed onto negative or neutral pictures, were studied in separate blocks (within-subjects using a deep or shallow encoding instruction (between-subjects. Following study, in Test 1, participants completed separate recognition test blocks for the words overlayed onto the negative and the neutral contexts. Following this, in Test 2, participants completed a recognition test for the foils from each Test 1 block. We found a significant three-way interaction on Test 2, such that individuals with high anxiety who initially studied target words using a shallow encoding instruction, demonstrated significantly elevated memory for foils that were contained within the negative Test 1 block. Results show that during retrieval (Test 1, participants re-entered the mode of processing (negative or neutral engaged at encoding, tainting the encoding of foils with that same mode of processing. The findings suggest that individuals with high relative to low anxiety, adopt a particularly salient negative retrieval mode, and this creates a downstream bias in encoding and subsequent retrieval of otherwise neutral information.

Signs of depth-luminance covariance in 3-D cluttered scenes.

Science.gov (United States)

Scaccia, Milena; Langer, Michael S

2018-03-01

In three-dimensional (3-D) cluttered scenes such as foliage, deeper surfaces often are more shadowed and hence darker, and so depth and luminance often have negative covariance. We examined whether the sign of depth-luminance covariance plays a role in depth perception in 3-D clutter. We compared scenes rendered with negative and positive depth-luminance covariance where positive covariance means that deeper surfaces are brighter and negative covariance means deeper surfaces are darker. For each scene, the sign of the depth-luminance covariance was given by occlusion cues. We tested whether subjects could use this sign information to judge the depth order of two target surfaces embedded in 3-D clutter. The clutter consisted of distractor surfaces that were randomly distributed in a 3-D volume. We tested three independent variables: the sign of the depth-luminance covariance, the colors of the targets and distractors, and the background luminance. An analysis of variance showed two main effects: Subjects performed better when the deeper surfaces were darker and when the color of the target surfaces was the same as the color of the distractors. There was also a strong interaction: Subjects performed better under a negative depth-luminance covariance condition when targets and distractors had different colors than when they had the same color. Our results are consistent with a "dark means deep" rule, but the use of this rule depends on the similarity between the color of the targets and color of the 3-D clutter.

Continuity in Multi-Device Interaction

DEFF Research Database (Denmark)

Raptis, Dimitrios; Kjeldskov, Jesper; Skov, Mikael

2016-01-01

’s Continuity. The study was done through surveying 3361 posts from technology web sites, discussion forums, and blogs, with a qualitative analysis of 1603 posts. Our findings present challenges in six themes of privacy, appropriation, customization, awareness, exclusion, and troubleshooting in relation...

Novel p38α MAP kinase inhibitors identified from yoctoReactor DNA-encoded small molecule library

DEFF Research Database (Denmark)

Petersen, L. K.; Blakskjær, P.; Chaikuad, A.

2016-01-01

A highly specific and potent (7 nM cellular IC50) inhibitor of p38α kinase was identified directly from a 12.6 million membered DNA-encoded small molecule library. This was achieved using the high fidelity yoctoReactor technology (yR) for preparing the DNA-encoded library, and a homogeneous...... interactions. Moreover, the crystal structure showed, that although buried in the p38α active site, the original DNA attachment point of the compound was accessible through a channel created by the distorted P-loop conformation. This study demonstrates the usability of DNA-encoded library technologies...

Performance evaluation of extended depth of field microscopy in the presence of spherical aberration and noise

Science.gov (United States)

King, Sharon V.; Yuan, Shuai; Preza, Chrysanthe

2018-03-01

Effectiveness of extended depth of field microscopy (EDFM) implementation with wavefront encoding methods is reduced by depth-induced spherical aberration (SA) due to reliance of this approach on a defined point spread function (PSF). Evaluation of the engineered PSF's robustness to SA, when a specific phase mask design is used, is presented in terms of the final restored image quality. Synthetic intermediate images were generated using selected generalized cubic and cubic phase mask designs. Experimental intermediate images were acquired using the same phase mask designs projected from a liquid crystal spatial light modulator. Intermediate images were restored using the penalized space-invariant expectation maximization and the regularized linear least squares algorithms. In the presence of depth-induced SA, systems characterized by radially symmetric PSFs, coupled with model-based computational methods, achieve microscope imaging performance with fewer deviations in structural fidelity (e.g., artifacts) in simulation and experiment and 50% more accurate positioning of 1-μm beads at 10-μm depth in simulation than those with radially asymmetric PSFs. Despite a drop in the signal-to-noise ratio after processing, EDFM is shown to achieve the conventional resolution limit when a model-based reconstruction algorithm with appropriate regularization is used. These trends are also found in images of fixed fluorescently labeled brine shrimp, not adjacent to the coverslip, and fluorescently labeled mitochondria in live cells.

Evaluation of Tire/Surfacing/Base Contact Stresses and Texture Depth

Directory of Open Access Journals (Sweden)

W.J.vdM. Steyn

2015-03-01

Full Text Available Tire rolling resistance has a major impact on vehicle fuel consumption. Rolling resistance is the loss of energy due to the interaction between the tire and the pavement surface. This interaction is a complicated combination of stresses and strains which depend on both tire and pavement related factors. These include vehicle speed, vehicle weight, tire material and type, road camber, tire inflation pressure, pavement surfacing texture etc. In this paper the relationship between pavement surface texture depth and tire/surfacing contact stress and area is investigated. Texture depth and tire/surfacing contact stress were measured for a range of tire inflation pressures on five different pavement surfaces. In the analysis the relationship between texture and the generated contact stresses as well as the contact stress between the surfacing and base layer are presented and discussed, and the anticipated effect of these relationships on the rolling resistance of vehicles on the surfacings, and subsequent vehicle fuel economy discussed.

Effect of sowing depth and mulch application on emergence and ...

African Journals Online (AJOL)

STORAGESEVER

2010-03-08

Mar 8, 2010 ... emergence and growth of shea butter tree seedlings. (Vitellaria paradoxa ... the effect of seed source, sowing depth and mulching status on seedling emergence and growth. Factorial ... The superior seedling emergence of no-mulch treated plots ..... Results of the second order interaction are pre- sented in ...

Exploring replay value: Shifts and continuities in user experiences between first and second exposure to an interactive story

OpenAIRE

Roth, C.; Vermeulen, I.E.; Vorderer, P.A.; Klimmt, C.

2012-01-01

While replay value is a common term in interactive entertainment, psychological research on its meaning in terms of user experiences is sparse. An exploratory experiment using the interactive drama "Façade" was conducted (n=50) to examine shifts and continuities in entertainment-related user experiences between first and second exposure to the same system. A questionnaire with brief scales measuring various user-experience dimensions (interaction-related facets such as usability, flow, and pr...

Sculpting proteins interactively: continual energy minimization embedded in a graphical modeling system.

Science.gov (United States)

Surles, M C; Richardson, J S; Richardson, D C; Brooks, F P

1994-02-01

We describe a new paradigm for modeling proteins in interactive computer graphics systems--continual maintenance of a physically valid representation, combined with direct user control and visualization. This is achieved by a fast algorithm for energy minimization, capable of real-time performance on all atoms of a small protein, plus graphically specified user tugs. The modeling system, called Sculpt, rigidly constrains bond lengths, bond angles, and planar groups (similar to existing interactive modeling programs), while it applies elastic restraints to minimize the potential energy due to torsions, hydrogen bonds, and van der Waals and electrostatic interactions (similar to existing batch minimization programs), and user-specified springs. The graphical interface can show bad and/or favorable contacts, and individual energy terms can be turned on or off to determine their effects and interactions. Sculpt finds a local minimum of the total energy that satisfies all the constraints using an augmented Lagrange-multiplier method; calculation time increases only linearly with the number of atoms because the matrix of constraint gradients is sparse and banded. On a 100-MHz MIPS R4000 processor (Silicon Graphics Indigo), Sculpt achieves 11 updates per second on a 20-residue fragment and 2 updates per second on an 80-residue protein, using all atoms except non-H-bonding hydrogens, and without electrostatic interactions. Applications of Sculpt are described: to reverse the direction of bundle packing in a designed 4-helix bundle protein, to fold up a 2-stranded beta-ribbon into an approximate beta-barrel, and to design the sequence and conformation of a 30-residue peptide that mimics one partner of a protein subunit interaction. Computer models that are both interactive and physically realistic (within the limitations of a given force field) have 2 significant advantages: (1) they make feasible the modeling of very large changes (such as needed for de novo design), and

Digital Analysis of Sit-to-Stand in Masters Athletes, Healthy Old People, and Young Adults Using a Depth Sensor

Directory of Open Access Journals (Sweden)

Daniel Leightley

2018-03-01

Full Text Available The aim of this study was to compare the performance between young adults (n = 15, healthy old people (n = 10, and masters athletes (n = 15 using a depth sensor and automated digital assessment framework. Participants were asked to complete a clinically validated assessment of the sit-to-stand technique (five repetitions, which was recorded using a depth sensor. A feature encoding and evaluation framework to assess balance, core, and limb performance using time- and speed-related measurements was applied to markerless motion capture data. The associations between the measurements and participant groups were examined and used to evaluate the assessment framework suitability. The proposed framework could identify phases of sit-to-stand, stability, transition style, and performance between participant groups with a high degree of accuracy. In summary, we found that a depth sensor coupled with the proposed framework could identify performance subtleties between groups.

Digital Analysis of Sit-to-Stand in Masters Athletes, Healthy Old People, and Young Adults Using a Depth Sensor.

Science.gov (United States)

Leightley, Daniel; Yap, Moi Hoon

2018-03-02

The aim of this study was to compare the performance between young adults ( n = 15), healthy old people ( n = 10), and masters athletes ( n = 15) using a depth sensor and automated digital assessment framework. Participants were asked to complete a clinically validated assessment of the sit-to-stand technique (five repetitions), which was recorded using a depth sensor. A feature encoding and evaluation framework to assess balance, core, and limb performance using time- and speed-related measurements was applied to markerless motion capture data. The associations between the measurements and participant groups were examined and used to evaluate the assessment framework suitability. The proposed framework could identify phases of sit-to-stand, stability, transition style, and performance between participant groups with a high degree of accuracy. In summary, we found that a depth sensor coupled with the proposed framework could identify performance subtleties between groups.

Analysing and Comparing Encodability Criteria

Directory of Open Access Journals (Sweden)

Kirstin Peters

2015-08-01

Full Text Available Encodings or the proof of their absence are the main way to compare process calculi. To analyse the quality of encodings and to rule out trivial or meaningless encodings, they are augmented with quality criteria. There exists a bunch of different criteria and different variants of criteria in order to reason in different settings. This leads to incomparable results. Moreover it is not always clear whether the criteria used to obtain a result in a particular setting do indeed fit to this setting. We show how to formally reason about and compare encodability criteria by mapping them on requirements on a relation between source and target terms that is induced by the encoding function. In particular we analyse the common criteria full abstraction, operational correspondence, divergence reflection, success sensitiveness, and respect of barbs; e.g. we analyse the exact nature of the simulation relation (coupled simulation versus bisimulation that is induced by different variants of operational correspondence. This way we reduce the problem of analysing or comparing encodability criteria to the better understood problem of comparing relations on processes.

Landscape encodings enhance optimization.

Directory of Open Access Journals (Sweden)

Konstantin Klemm

Full Text Available Hard combinatorial optimization problems deal with the search for the minimum cost solutions (ground states of discrete systems under strong constraints. A transformation of state variables may enhance computational tractability. It has been argued that these state encodings are to be chosen invertible to retain the original size of the state space. Here we show how redundant non-invertible encodings enhance optimization by enriching the density of low-energy states. In addition, smooth landscapes may be established on encoded state spaces to guide local search dynamics towards the ground state.

Landscape Encodings Enhance Optimization

Science.gov (United States)

Klemm, Konstantin; Mehta, Anita; Stadler, Peter F.

2012-01-01

Hard combinatorial optimization problems deal with the search for the minimum cost solutions (ground states) of discrete systems under strong constraints. A transformation of state variables may enhance computational tractability. It has been argued that these state encodings are to be chosen invertible to retain the original size of the state space. Here we show how redundant non-invertible encodings enhance optimization by enriching the density of low-energy states. In addition, smooth landscapes may be established on encoded state spaces to guide local search dynamics towards the ground state. PMID:22496860

Seeing Iconic Gestures While Encoding Events Facilitates Children's Memory of These Events.

Science.gov (United States)

Aussems, Suzanne; Kita, Sotaro

2017-11-08

An experiment with 72 three-year-olds investigated whether encoding events while seeing iconic gestures boosts children's memory representation of these events. The events, shown in videos of actors moving in an unusual manner, were presented with either iconic gestures depicting how the actors performed these actions, interactive gestures, or no gesture. In a recognition memory task, children in the iconic gesture condition remembered actors and actions better than children in the control conditions. Iconic gestures were categorized based on how much of the actors was represented by the hands (feet, legs, or body). Only iconic hand-as-body gestures boosted actor memory. Thus, seeing iconic gestures while encoding events facilitates children's memory of those aspects of events that are schematically highlighted by gesture. © 2017 The Authors. Child Development © 2017 Society for Research in Child Development, Inc.

Generalization of perceptual and motor learning: a causal link with memory encoding and consolidation?

Science.gov (United States)

Censor, N

2013-10-10

In both perceptual and motor learning, numerous studies have shown specificity of learning to the trained eye or hand and to the physical features of the task. However, generalization of learning is possible in both perceptual and motor domains. Here, I review evidence for perceptual and motor learning generalization, suggesting that generalization patterns are affected by the way in which the original memory is encoded and consolidated. Generalization may be facilitated during fast learning, with possible engagement of higher-order brain areas recurrently interacting with the primary visual or motor cortices encoding the stimuli or movements' memories. Such generalization may be supported by sleep, involving functional interactions between low and higher-order brain areas. Repeated exposure to the task may alter generalization patterns of learning and overall offline learning. Development of unifying frameworks across learning modalities and better understanding of the conditions under which learning can generalize may enable to gain insight regarding the neural mechanisms underlying procedural learning and have useful clinical implications. Copyright © 2013 IBRO. Published by Elsevier Ltd. All rights reserved.

Self-awareness and the subconscious effect of personal pronouns on word encoding: a magnetoencephalography (MEG) study.

Science.gov (United States)

Walla, Peter; Greiner, Katharina; Duregger, Cornelia; Deecke, Lüder; Thurner, Stefan

2007-03-02

The effect of personal pronouns such as "ein" (German for "a"), "mein" (German for "my") and "sein" (German for "his") on the processing of associated nouns was investigated using MEG. Three different encoding strategies were provided in order to vary the level of consciousness involved in verbal information processing. A shallow (alphabetic), a deep (semantic) and a very deep (contextual) encoding instruction related to visual word presentation were given to all study participants. After the encoding of pronoun-noun pairs, recognition performances of nouns only were tested. The number of correctly recognized nouns previously associated with "sein" was significantly lower than the number of correctly recognized nouns previously associated with "ein" in the shallow encoding condition. The same trend was found for "mein" associated nouns which were also less accurately recognized compared to "ein" associated nouns. Magnetic field distributions recorded during the encoding phases revealed two significant effects, one between about 200 and 400ms after stimulus onset and the other between about 500 and 800ms. The earlier effect was found over occipito-parietal sensors, whereas the later effect occurred over left frontal sensors. Within both time ranges, brain activation varied significantly as a function of associated pronoun independent of depth of word processing. In the respective areas of both time ranges, conditions including personal pronouns ("mein" and "sein") showed higher magnetic field components compared to the control condition of no personal pronouns ("ein"). Evidence is shown that early stage processing is able to distinguish between no personal and personal information, whereas later stage processing is able to distinguish between information related to oneself and to another person (self and non-self). Along with other previous reports our MEG findings support the notion that particular human brain functions involved in processing neurophysiological

Shear bond strength of self-etch and total-etch bonding systems at different dentin depths

Directory of Open Access Journals (Sweden)

Ana Carolina Maito Villela-Rosa

2011-04-01

Full Text Available The purpose of this study was to evaluate the dentin shear bond strength of four adhesive systems (Adper Single Bond 2, Adper Prompt L-Pop, Magic Bond DE and Self Etch Bond in regards to buccal and lingual surfaces and dentin depth. Forty extracted third molars had roots removed and crowns bisected in the mesiodistal direction. The buccal and lingual surfaces were fixed in a PVC/acrylic resin ring and were divided into buccal and lingual groups assigned to each selected adhesive. The same specimens prepared for the evaluation of superficial dentin shear resistance were used to evaluate the different depths of dentin. The specimens were identified and abraded at depths of 0.5, 1.0, 1.5 and 2.0 mm. Each depth was evaluated by ISO TR 11405 using an EMIC-2000 machine regulated at 0.5 mm/min with a 200 Kgf load cell. We performed statistical analyses on the results (ANOVA, Tukey and Scheffé tests. Data revealed statistical differences (p < 0.01 in the adhesive and depth variation as well as adhesive/depth interactions. The Adper Single Bond 2 demonstrated the highest mean values of shear bond strength. The Prompt L-Pop product, a self-etching adhesive, revealed higher mean values compared with Magic Bond DE and Self Etch Bond adhesives, a total and self-etching adhesive respectively. It may be concluded that the shear bond strength of dentin is dependent on material (adhesive system, substrate depth and adhesive/depth interaction.

Beyond initial encoding: Measures of the post-encoding status of memory traces predict long-term recall in infancy

OpenAIRE

Pathman, Thanujeni; Bauer, Patricia J.

2012-01-01

The first years of life are witness to rapid changes in long-term recall ability. In the present research, we contributed to explanation of the changes by testing the absolute and relative contributions to long-term recall of encoding and post-encoding processes. Using elicited imitation, we sampled the status of 16-, 20-, and 24-month-old infants’ memory representations at various time points after experience of events. In Experiment 1, infants were tested immediately, 1 week after encoding,...

Relationship between Secchi depth and the diffuse light attenuation coefficient in Danish estuaries

DEFF Research Database (Denmark)

Murray, Ciarán; Markager, Stiig

Analyis of temporal and spatial variation in the in the relationship between light attenuation and Secchi depth in Danish monitoring data There can be found timeseries of Secchi depth measurements in Danish waters which extend relatively far back in time. The Secchi depth measurement is therefore...... useful in that it allows comparison of present conditions with these older observations. An empirical inverse relationship between Secchi depth and light attenuation coefficient, Kd, has traditionally been used to estimate the light attenuation coefficient from Secchi depth measurements. However, studies...... have shown that the assumption of a constant inverse relationship between Kd and Secchi depth does not hold. The authors have analyzed measurements of Secchi depth and light attenuation from Danish monitoring data. The data used in our investigation was collected over a continuous period from 1986...

Inert gas narcosis disrupts encoding but not retrieval of long term memory.

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Hobbs, Malcolm; Kneller, Wendy

2015-05-15

Exposure to increased ambient pressure causes inert gas narcosis of which one symptom is long-term memory (LTM) impairment. Narcosis is posited to impair LTM by disrupting information encoding, retrieval (self-guided search), or both. The effect of narcosis on the encoding and retrieval of LTM was investigated by testing the effect of learning-recall pressure and levels of processing (LoP) on the free-recall of word lists in divers underwater. All participants (n=60) took part in four conditions in which words were learnt and then recalled at either low pressure (1.4-1.9atm/4-9msw) or high pressure (4.4-5.0atm/34-40msw), as manipulated by changes in depth underwater: low-low (LL), low-high(LH), high-high (HH), and high-low (HL). In addition, participants were assigned to either a deep or shallow processing condition, using LoP methodology. Free-recall memory ability was significantly impaired only when words were initially learned at high pressure (HH & HL conditions). When words were learned at low pressure and then recalled at low pressure (LL condition) or high pressure (LH condition) free-recall was not impaired. Although numerically superior in several conditions, deeper processing failed to significantly improve free-recall ability in any of the learning-recall conditions. This pattern of results support the hypothesis that narcosis disrupts encoding of information into LTM, while retrieval appears to be unaffected. These findings are discussed in relation to similar effects reported by some memory impairing drugs and the practical implications for workers in pressurised environments. Copyright © 2015 Elsevier Inc. All rights reserved.

GPU-accelerated depth map generation for X-ray simulations of complex CAD geometries

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Grandin, Robert J.; Young, Gavin; Holland, Stephen D.; Krishnamurthy, Adarsh

2018-04-01

Interactive x-ray simulations of complex computer-aided design (CAD) models can provide valuable insights for better interpretation of the defect signatures such as porosity from x-ray CT images. Generating the depth map along a particular direction for the given CAD geometry is the most compute-intensive step in x-ray simulations. We have developed a GPU-accelerated method for real-time generation of depth maps of complex CAD geometries. We preprocess complex components designed using commercial CAD systems using a custom CAD module and convert them into a fine user-defined surface tessellation. Our CAD module can be used by different simulators as well as handle complex geometries, including those that arise from complex castings and composite structures. We then make use of a parallel algorithm that runs on a graphics processing unit (GPU) to convert the finely-tessellated CAD model to a voxelized representation. The voxelized representation can enable heterogeneous modeling of the volume enclosed by the CAD model by assigning heterogeneous material properties in specific regions. The depth maps are generated from this voxelized representation with the help of a GPU-accelerated ray-casting algorithm. The GPU-accelerated ray-casting method enables interactive (> 60 frames-per-second) generation of the depth maps of complex CAD geometries. This enables arbitrarily rotation and slicing of the CAD model, leading to better interpretation of the x-ray images by the user. In addition, the depth maps can be used to aid directly in CT reconstruction algorithms.

Optical Detection and Sizing of Single Nano-Particles Using Continuous Wetting Films

Science.gov (United States)

Hennequin, Yves; McLeod, Euan; Mudanyali, Onur; Migliozzi, Daniel; Ozcan, Aydogan; Dinten, Jean-Marc

2013-01-01

The physical interaction between nano-scale objects and liquid interfaces can create unique optical properties, enhancing the signatures of the objects with sub-wavelength features. Here we show that the evaporation on a wetting substrate of a polymer solution containing sub-micrometer or nano-scale particles creates liquid micro-lenses that arise from the local deformations of the continuous wetting film. These micro-lenses have properties similar to axicon lenses that are known to create beams with a long depth of focus. This enhanced depth of focus allows detection of single nanoparticles using a low magnification microscope objective lens, achieving a relatively wide field-of-view, while also lifting the constraints on precise focusing onto the object plane. Hence, by creating these liquid axicon lenses through spatial deformations of a continuous thin wetting film, we transfer the challenge of imaging individual nano-particles to detecting the light focused by these lenses. As a proof of concept, we demonstrate the detection and sizing of single nano-particles (100 and 200 nm), CpGV granuloviruses as well as Staphylococcus epidermidis bacteria over a wide field of view of e.g., 5.10×3.75 mm2 using a ×5 objective lens with a numerical aperture of 0.15. In addition to conventional lens-based microscopy, this continuous wetting film based approach is also applicable to lensfree computational on-chip imaging, which can be used to detect single nano-particles over a large field-of-view of e.g., >20-30 mm2. These results could be especially useful for high-throughput field-analysis of nano-scale objects using compact and cost-effective microscope designs. PMID:23889001

Lateral and medial prefrontal contributions to emotion generation by semantic elaboration during episodic encoding.

Science.gov (United States)

Kaneda, Takumi; Shigemune, Yayoi; Tsukiura, Takashi

2017-02-01

Memories for emotion-laden stimuli are remembered more accurately than those for neutral stimuli. Although this enhancement reflects stimulus-driven modulation of memory by emotions, functional neuroimaging evidence of the interacting mechanisms between emotions generated by intentional processes, such as semantic elaboration, and memory is scarce. The present fMRI study investigated how encoding-related activation is modulated by emotions generated during the process of semantic elaboration. During encoding with fMRI, healthy young adults viewed neutral (target) pictures either passively or with semantic elaboration. In semantic elaboration, participants imagined background stories related to the pictures. Encoding trials with semantic elaboration were subdivided into conditions in which participants imagined negative, positive, or neutral stories. One week later, memories for target pictures were tested. In behavioral results, memories for target pictures were significantly enhanced by semantic elaboration, compared to passive viewing, and the memory enhancement was more remarkable when negative or positive stories were imagined. fMRI results demonstrated that activations in the left inferior frontal gyrus and dorsal medial prefrontal cortex (dmPFC) were greater during the encoding of target pictures with semantic elaboration than those with passive viewing, and that these activations further increased during encoding with semantic elaboration of emotional stories than of neutral stories. Functional connectivity between the left inferior frontal gyrus and dmPFC/hippocampus during encoding significantly predicted retrieval accuracies of memories encoded with self-generated emotional stories. These findings suggest that networks including the left inferior frontal region, dmPFC, and hippocampus could contribute to the modulation of memories encoded with the emotion generation.

A Sequence-Specific Interaction between the Saccharomyces cerevisiae rRNA Gene Repeats and a Locus Encoding an RNA Polymerase I Subunit Affects Ribosomal DNA Stability

Science.gov (United States)

Cahyani, Inswasti; Cridge, Andrew G.; Engelke, David R.; Ganley, Austen R. D.

2014-01-01

The spatial organization of eukaryotic genomes is linked to their functions. However, how individual features of the global spatial structure contribute to nuclear function remains largely unknown. We previously identified a high-frequency interchromosomal interaction within the Saccharomyces cerevisiae genome that occurs between the intergenic spacer of the ribosomal DNA (rDNA) repeats and the intergenic sequence between the locus encoding the second largest RNA polymerase I subunit and a lysine tRNA gene [i.e., RPA135-tK(CUU)P]. Here, we used quantitative chromosome conformation capture in combination with replacement mapping to identify a 75-bp sequence within the RPA135-tK(CUU)P intergenic region that is involved in the interaction. We demonstrate that the RPA135-IGS1 interaction is dependent on the rDNA copy number and the Msn2 protein. Surprisingly, we found that the interaction does not govern RPA135 transcription. Instead, replacement of a 605-bp region within the RPA135-tK(CUU)P intergenic region results in a reduction in the RPA135-IGS1 interaction level and fluctuations in rDNA copy number. We conclude that the chromosomal interaction that occurs between the RPA135-tK(CUU)P and rDNA IGS1 loci stabilizes rDNA repeat number and contributes to the maintenance of nucleolar stability. Our results provide evidence that the DNA loci involved in chromosomal interactions are composite elements, sections of which function in stabilizing the interaction or mediating a functional outcome. PMID:25421713

Extreme expansion of NBS-encoding genes in Rosaceae.

Science.gov (United States)

Jia, YanXiao; Yuan, Yang; Zhang, Yanchun; Yang, Sihai; Zhang, Xiaohui

2015-05-03

Nucleotide binding site leucine-rich repeats (NBS-LRR) genes encode a large class of disease resistance (R) proteins in plants. Extensive studies have been carried out to identify and investigate NBS-encoding gene families in many important plant species. However, no comprehensive research into NBS-encoding genes in the Rosaceae has been performed. In this study, five whole-genome sequenced Rosaceae species, including apple, pear, peach, mei, and strawberry, were analyzed to investigate the evolutionary pattern of NBS-encoding genes and to compare them to those of three Cucurbitaceae species, cucumber, melon, and watermelon. Considerable differences in the copy number of NBS-encoding genes were observed between Cucurbitaceae and Rosaceae species. In Rosaceae species, a large number and a high proportion of NBS-encoding genes were observed in peach (437, 1.52%), mei (475, 1.51%), strawberry (346, 1.05%) and pear (617, 1.44%), and apple contained a whopping 1303 (2.05%) NBS-encoding genes, which might be the highest number of R-genes in all of these reported diploid plant. However, no more than 100 NBS-encoding genes were identified in Cucurbitaceae. Many more species-specific gene families were classified and detected with the signature of positive selection in Rosaceae species, especially in the apple genome. Taken together, our findings indicate that NBS-encoding genes in Rosaceae, especially in apple, have undergone extreme expansion and rapid adaptive evolution. Useful information was provided for further research on the evolutionary mode of disease resistance genes in Rosaceae crops.

Learning science as a potential new source of understanding and improvement for continuing education and continuing professional development.

Science.gov (United States)

Van Hoof, Thomas J; Doyle, Terrence J

2018-01-15

Learning science is an emerging interdisciplinary field that offers educators key insights about what happens in the brain when learning occurs. In addition to explanations about the learning process, which includes memory and involves different parts of the brain, learning science offers effective strategies to inform the planning and implementation of activities and programs in continuing education and continuing professional development. This article provides a brief description of learning, including the three key steps of encoding, consolidation and retrieval. The article also introduces four major learning-science strategies, known as distributed learning, retrieval practice, interleaving, and elaboration, which share the importance of considerable practice. Finally, the article describes how learning science aligns with the general findings from the most recent synthesis of systematic reviews about the effectiveness of continuing medical education.

Quantifying spatial variability of depth of peat burn in wetlands in relation to antecedent characteristics using field data, multi-temporal and multi-spectral LiDAR

Science.gov (United States)

Chasmer, L.; Flade, L.; Virk, R.; Montgomery, J. S.; Hopkinson, C.; Thompson, D. K.; Petrone, R. M.; Devito, K.

2017-12-01

Landscape changes in the hydrological characteristics of wetlands in some parts of the Boreal region of Canada are occurring as a result of climate-induced feedbacks and anthropogenic disturbance. Wetlands are largely resilient to wildfire, however, natural, climatic and anthropogenic disturbances can change surface water regimes and predispose wetlands to greater depth of peat burn. Over broad areas, peat loss contributes to significant pollution emissions, which can affect community health. In this study, we a) quantify depth of peat burn and relationships to antecedent conditions (species type, topography, surficial geology) within three classified wetlands found in the Boreal Plains ecoregion of western Canada; and b) examine the impacts of wildfire on post-fire ground surface energy balance to determine how peat loss might affect local hydro-climatology and surface water feedbacks. High-resolution optical imagery, pre- and post-burn multi-spectral Light Detection And Ranging (LiDAR), airborne thermal infrared imagery, and field validation data products are integrated to identify multiple complex interactions within the study wetlands. LiDAR-derived depth of peat burn is within 1 cm (average) compared with measured (RMSE = 9 cm over the control surface), demonstrating the utility of LiDAR with high point return density. Depth of burn also correlates strongly with variations in Normalised Burn Ratio (NBR) determined for ground surfaces only. Antecedent conditions including topographic position, soil moisture, soil type and wetland species also have complex interactions with depth of peat loss within wetlands observed in other studies. However, while field measurements are important for validation and understanding eco-hydrological processes, results from remote sensing are spatially continuous. Temporal LiDAR data illustrate the full range of variability in depth of burn and wetland characteristics following fire. Finally, measurements of instantaneous surface

batman Interacts with polycomb and trithorax group genes and encodes a BTB/POZ protein that is included in a complex containing GAGA factor.

Science.gov (United States)

Faucheux, M; Roignant, J-Y; Netter, S; Charollais, J; Antoniewski, C; Théodore, L

2003-02-01

Polycomb and trithorax group genes maintain the appropriate repressed or activated state of homeotic gene expression throughout Drosophila melanogaster development. We have previously identified the batman gene as a Polycomb group candidate since its function is necessary for the repression of Sex combs reduced. However, our present genetic analysis indicates functions of batman in both activation and repression of homeotic genes. The 127-amino-acid Batman protein is almost reduced to a BTB/POZ domain, an evolutionary conserved protein-protein interaction domain found in a large protein family. We show that this domain is involved in the interaction between Batman and the DNA binding GAGA factor encoded by the Trithorax-like gene. The GAGA factor and Batman codistribute on polytene chromosomes, coimmunoprecipitate from nuclear embryonic and larval extracts, and interact in the yeast two-hybrid assay. Batman, together with the GAGA factor, binds to MHS-70, a 70-bp fragment of the bithoraxoid Polycomb response element. This binding, like that of the GAGA factor, requires the presence of d(GA)n sequences. Together, our results suggest that batman belongs to a subset of the Polycomb/trithorax group of genes that includes Trithorax-like, whose products are involved in both activation and repression of homeotic genes.

Seeing iconic gestures while encoding events facilitates children's memory of these events

OpenAIRE

Aussems, Suzanne; Kita, Sotaro

2017-01-01

An experiment with 72 three-year-olds investigated whether encoding events while seeing iconic gestures boosts children's memory representation of these events. The events, shown in videos of actors moving in an unusual manner, were presented with either iconic gestures depicting how the actors performed these actions, interactive gestures, or no gesture. In a recognition memory task, children in the iconic gesture condition remembered actors and actions better than children in the control co...

The Drosophila melanogaster DmCK2beta transcription unit encodes for functionally non-redundant protein isoforms.

Science.gov (United States)

Jauch, Eike; Wecklein, Heike; Stark, Felix; Jauch, Mandy; Raabe, Thomas

2006-06-07

Genes encoding for the two evolutionary highly conserved subunits of a heterotetrameric protein kinase CK2 holoenzyme are present in all examined eukaryotic genomes. Depending on the organism, multiple transcription units encoding for a catalytically active CK2alpha subunit and/or a regulatory CK2beta subunit may exist. The phosphotransferase activity of members of the protein kinase CK2alpha family is thought to be independent of second messengers but is modulated by interaction with CK2beta-like proteins. In the genome of Drosophila melanogaster, one gene encoding for a CK2alpha subunit and three genes encoding for CK2beta-like proteins are present. The X-linked DmCK2beta transcription unit encodes for several CK2beta protein isoforms due to alternative splicing of its primary transcript. We addressed the question whether CK2beta-like proteins are redundant in function. Our in vivo experiments show that variations of the very C-terminal tail of CK2beta isoforms encoded by the X-linked DmCK2beta transcription unit influence their functional properties. In addition, we find that CK2beta-like proteins encoded by the autosomal D. melanogaster genes CK2betates and CK2beta' cannot fully substitute for a loss of CK2beta isoforms encoded by DmCK2beta.

Brownian dynamics simulations of a flexible polymer chain which includes continuous resistance and multibody hydrodynamic interactions

Science.gov (United States)

Butler, Jason E.; Shaqfeh, Eric S. G.

2005-01-01

Using methods adapted from the simulation of suspension dynamics, we have developed a Brownian dynamics algorithm with multibody hydrodynamic interactions for simulating the dynamics of polymer molecules. The polymer molecule is modeled as a chain composed of a series of inextensible, rigid rods with constraints at each joint to ensure continuity of the chain. The linear and rotational velocities of each segment of the polymer chain are described by the slender-body theory of Batchelor [J. Fluid Mech. 44, 419 (1970)]. To include hydrodynamic interactions between the segments of the chain, the line distribution of forces on each segment is approximated by making a Legendre polynomial expansion of the disturbance velocity on the segment, where the first two terms of the expansion are retained in the calculation. Thus, the resulting linear force distribution is specified by a center of mass force, couple, and stresslet on each segment. This method for calculating the hydrodynamic interactions has been successfully used to simulate the dynamics of noncolloidal suspensions of rigid fibers [O. G. Harlen, R. R. Sundararajakumar, and D. L. Koch, J. Fluid Mech. 388, 355 (1999); J. E. Butler and E. S. G. Shaqfeh, J. Fluid Mech. 468, 204 (2002)]. The longest relaxation time and center of mass diffusivity are among the quantities calculated with the simulation technique. Comparisons are made for different levels of approximation of the hydrodynamic interactions, including multibody interactions, two-body interactions, and the "freely draining" case with no interactions. For the short polymer chains studied in this paper, the results indicate a difference in the apparent scaling of diffusivity with polymer length for the multibody versus two-body level of approximation for the hydrodynamic interactions.

High-resolution orientation and depth of insertion of the voltage-sensing S4 helix of a potassium channel in lipid bilayers.

Science.gov (United States)

Doherty, Tim; Su, Yongchao; Hong, Mei

2010-08-27

The opening and closing of voltage-gated potassium (Kv) channels are controlled by several conserved Arg residues in the S4 helix of the voltage-sensing domain. The interaction of these positively charged Arg residues with the lipid membrane has been of intense interest for understanding how membrane proteins fold to allow charged residues to insert into lipid bilayers against free-energy barriers. Using solid-state NMR, we have now determined the orientation and insertion depth of the S4 peptide of the KvAP channel in lipid bilayers. Two-dimensional (15)N correlation experiments of macroscopically oriented S4 peptide in phospholipid bilayers revealed a tilt angle of 40 degrees and two possible rotation angles differing by 180 degrees around the helix axis. Remarkably, the tilt angle and one of the two rotation angles are identical to those of the S4 helix in the intact voltage-sensing domain, suggesting that interactions between the S4 segment and other helices of the voltage-sensing domain are not essential for the membrane topology of the S4 helix. (13)C-(31)P distances between the S4 backbone and the lipid (31)P indicate a approximately 9 A local thinning and 2 A average thinning of the DMPC (1,2-dimyristoyl-sn-glycero-3-phosphochloline)/DMPG (1,2-dimyristoyl-sn-glycero-3-phosphatidylglycerol) bilayer, consistent with neutron diffraction data. Moreover, a short distance of 4.6 A from the guanidinium C(zeta) of the second Arg to (31)P indicates the existence of guanidinium phosphate hydrogen bonding and salt bridges. These data suggest that the structure of the Kv gating helix is mainly determined by protein-lipid interactions instead of interhelical protein-protein interactions, and the S4 amino acid sequence encodes sufficient information for the membrane topology of this crucial gating helix. Copyright (c) 2010 Elsevier Ltd. All rights reserved.