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Sample records for multiple thresholds arise

  1. Multiple eruptive keratoacanthomas arising in a tattoo.

    PubMed

    Vitiello, Magalys; Echeverria, Begoña; Romanelli, Paolo; Abuchar, Adriana; Kerdel, Francisco

    2010-07-01

    Keratoacanthomas are rapidly growing, keratinizing, epithelial neoplasms that tend to spontaneously involute and are rarely multiple or eruptive. There is still disagreement on whether or not this condition is a malignancy or a benign epidermal neoplasm; nevertheless, its appearance on tattoos has been reported in rare instances. When waiting for spontaneous involution is not an option, surgery is the preferred treatment. Other therapeutic modalities used for the treatment of this condition include radiotherapy; cryotherapy; laser therapy; and multiple intralesional, topical, and systemic agents. The authors report a patient who developed multiple, eruptive keratoacanthomas in the red ink portions of a tattoo and was successfully treated with acitretin. PMID:20725558

  2. Fractional killing arises from cell-to-cell variability in overcoming a caspase activity threshold

    PubMed Central

    Roux, Jérémie; Hafner, Marc; Bandara, Samuel; Sims, Joshua J; Hudson, Hannah; Chai, Diana; Sorger, Peter K

    2015-01-01

    When cells are exposed to death ligands such as TRAIL, a fraction undergoes apoptosis and a fraction survives; if surviving cells are re-exposed to TRAIL, fractional killing is once again observed. Therapeutic antibodies directed against TRAIL receptors also cause fractional killing, even at saturating concentrations, limiting their effectiveness. Fractional killing arises from cell-to-cell fluctuations in protein levels (extrinsic noise), but how this results in a clean bifurcation between life and death remains unclear. In this paper, we identify a threshold in the rate and timing of initiator caspase activation that distinguishes cells that live from those that die; by mapping this threshold, we can predict fractional killing of cells exposed to natural and synthetic agonists alone or in combination with sensitizing drugs such as bortezomib. A phenomenological model of the threshold also quantifies the contributions of two resistance genes (c-FLIP and Bcl-2), providing new insight into the control of cell fate by opposing pro-death and pro-survival proteins and suggesting new criteria for evaluating the efficacy of therapeutic TRAIL receptor agonists. PMID:25953765

  3. Fractional killing arises from cell-to-cell variability in overcoming a caspase activity threshold.

    PubMed

    Roux, Jérémie; Hafner, Marc; Bandara, Samuel; Sims, Joshua J; Hudson, Hannah; Chai, Diana; Sorger, Peter K

    2015-05-01

    When cells are exposed to death ligands such as TRAIL, a fraction undergoes apoptosis and a fraction survives; if surviving cells are re-exposed to TRAIL, fractional killing is once again observed. Therapeutic antibodies directed against TRAIL receptors also cause fractional killing, even at saturating concentrations, limiting their effectiveness. Fractional killing arises from cell-to-cell fluctuations in protein levels (extrinsic noise), but how this results in a clean bifurcation between life and death remains unclear. In this paper, we identify a threshold in the rate and timing of initiator caspase activation that distinguishes cells that live from those that die; by mapping this threshold, we can predict fractional killing of cells exposed to natural and synthetic agonists alone or in combination with sensitizing drugs such as bortezomib. A phenomenological model of the threshold also quantifies the contributions of two resistance genes (c-FLIP and Bcl-2), providing new insight into the control of cell fate by opposing pro-death and pro-survival proteins and suggesting new criteria for evaluating the efficacy of therapeutic TRAIL receptor agonists. PMID:25953765

  4. Multiple benefits arising from novel management of agricultural ditches

    NASA Astrophysics Data System (ADS)

    Jonczyk, Jennine; Barber, Nick; Quinn, Paul

    2016-04-01

    The opportunity to modify the function and dynamics of farm ditches is very high. There are many kilometres of ditch that could offer multiple benefits to pollution control and lowering flood risk. However, there is first a perception problem to overcome, in that most farmers wish to remove water from the land quickly and are irritated by the accumulation of sediment. Hence, we have built a series of demonstration ditches where the new operation of the ditch can be shown to trap substantial amounts of sediment and nutrients and also not cause any local flooding or water logging problems. The ditch itself is radically changed in shape and is widened as much as possible and usually has a flat bottom. The ditch will also contain a series of leaky barriers that will retain flow during storm events. In very large events an overflow structure is required. These features do have to be engineered to a good level of safety to avoid failure. Sediment must also be recovered from the ditch frequently (at least annually) which again could be a role fulfilled by the farmer. We will show a number of example ditch designs and the data captured in experiments. One feature typically captures 50% of the suspended sediment, 30% of total phosphorus and 20% of the nitrate in a single storm.

  5. The Impact of Heterogeneous Thresholds on Social Contagion with Multiple Initiators

    PubMed Central

    Karampourniotis, Panagiotis D.; Sreenivasan, Sameet; Szymanski, Boleslaw K.; Korniss, Gyorgy

    2015-01-01

    The threshold model is a simple but classic model of contagion spreading in complex social systems. To capture the complex nature of social influencing we investigate numerically and analytically the transition in the behavior of threshold-limited cascades in the presence of multiple initiators as the distribution of thresholds is varied between the two extreme cases of identical thresholds and a uniform distribution. We accomplish this by employing a truncated normal distribution of the nodes’ thresholds and observe a non-monotonic change in the cascade size as we vary the standard deviation. Further, for a sufficiently large spread in the threshold distribution, the tipping-point behavior of the social influencing process disappears and is replaced by a smooth crossover governed by the size of initiator set. We demonstrate that for a given size of the initiator set, there is a specific variance of the threshold distribution for which an opinion spreads optimally. Furthermore, in the case of synthetic graphs we show that the spread asymptotically becomes independent of the system size, and that global cascades can arise just by the addition of a single node to the initiator set. PMID:26571486

  6. The Impact of Heterogeneous Thresholds on Social Contagion with Multiple Initiators.

    PubMed

    Karampourniotis, Panagiotis D; Sreenivasan, Sameet; Szymanski, Boleslaw K; Korniss, Gyorgy

    2015-01-01

    The threshold model is a simple but classic model of contagion spreading in complex social systems. To capture the complex nature of social influencing we investigate numerically and analytically the transition in the behavior of threshold-limited cascades in the presence of multiple initiators as the distribution of thresholds is varied between the two extreme cases of identical thresholds and a uniform distribution. We accomplish this by employing a truncated normal distribution of the nodes' thresholds and observe a non-monotonic change in the cascade size as we vary the standard deviation. Further, for a sufficiently large spread in the threshold distribution, the tipping-point behavior of the social influencing process disappears and is replaced by a smooth crossover governed by the size of initiator set. We demonstrate that for a given size of the initiator set, there is a specific variance of the threshold distribution for which an opinion spreads optimally. Furthermore, in the case of synthetic graphs we show that the spread asymptotically becomes independent of the system size, and that global cascades can arise just by the addition of a single node to the initiator set. PMID:26571486

  7. Combining multiple thresholding binarization values to improve OCR output

    NASA Astrophysics Data System (ADS)

    Lund, William B.; Kennard, Douglas J.; Ringger, Eric K.

    2013-01-01

    For noisy, historical documents, a high optical character recognition (OCR) word error rate (WER) can render the OCR text unusable. Since image binarization is often the method used to identify foreground pixels, a body of research seeks to improve image-wide binarization directly. Instead of relying on any one imperfect binarization technique, our method incorporates information from multiple simple thresholding binarizations of the same image to improve text output. Using a new corpus of 19th century newspaper grayscale images for which the text transcription is known, we observe WERs of 13.8% and higher using current binarization techniques and a state-of-the-art OCR engine. Our novel approach combines the OCR outputs from multiple thresholded images by aligning the text output and producing a lattice of word alternatives from which a lattice word error rate (LWER) is calculated. Our results show a LWER of 7.6% when aligning two threshold images and a LWER of 6.8% when aligning five. From the word lattice we commit to one hypothesis by applying the methods of Lund et al. (2011) achieving an improvement over the original OCR output and a 8.41% WER result on this data set.

  8. Multiple seeds sensitivity using a single seed with threshold.

    PubMed

    Egidi, Lavinia; Manzini, Giovanni

    2015-08-01

    Spaced seeds are a fundamental tool for similarity search in biosequences. The best sensitivity/selectivity trade-offs are obtained using many seeds simultaneously: This is known as the multiple seed approach. Unfortunately, spaced seeds use a large amount of memory and the available RAM is a practical limit to the number of seeds one can use simultaneously. Inspired by some recent results on lossless seeds, we revisit the approach of using a single spaced seed and considering two regions homologous if the seed hits in at least t sufficiently close positions. We show that by choosing the locations of the don't care symbols in the seed using quadratic residues modulo a prime number, we derive single seeds that when used with a threshold t > 1 have competitive sensitivity/selectivity trade-offs, indeed close to the best multiple seeds known in the literature. In addition, the choice of the threshold t can be adjusted to modify sensitivity and selectivity a posteriori, thus enabling a more accurate search in the specific instance at issue. The seeds we propose also exhibit robustness and allow flexibility in usage. PMID:25747382

  9. Dynamic multiple thresholding breast boundary detection algorithm for mammograms

    SciTech Connect

    Wu, Yi-Ta; Zhou Chuan; Chan, Heang-Ping; Paramagul, Chintana; Hadjiiski, Lubomir M.; Daly, Caroline Plowden; Douglas, Julie A.; Zhang Yiheng; Sahiner, Berkman; Shi Jiazheng; Wei Jun

    2010-01-15

    Purpose: Automated detection of breast boundary is one of the fundamental steps for computer-aided analysis of mammograms. In this study, the authors developed a new dynamic multiple thresholding based breast boundary (MTBB) detection method for digitized mammograms. Methods: A large data set of 716 screen-film mammograms (442 CC view and 274 MLO view) obtained from consecutive cases of an Institutional Review Board approved project were used. An experienced breast radiologist manually traced the breast boundary on each digitized image using a graphical interface to provide a reference standard. The initial breast boundary (MTBB-Initial) was obtained by dynamically adapting the threshold to the gray level range in local regions of the breast periphery. The initial breast boundary was then refined by using gradient information from horizontal and vertical Sobel filtering to obtain the final breast boundary (MTBB-Final). The accuracy of the breast boundary detection algorithm was evaluated by comparison with the reference standard using three performance metrics: The Hausdorff distance (HDist), the average minimum Euclidean distance (AMinDist), and the area overlap measure (AOM). Results: In comparison with the authors' previously developed gradient-based breast boundary (GBB) algorithm, it was found that 68%, 85%, and 94% of images had HDist errors less than 6 pixels (4.8 mm) for GBB, MTBB-Initial, and MTBB-Final, respectively. 89%, 90%, and 96% of images had AMinDist errors less than 1.5 pixels (1.2 mm) for GBB, MTBB-Initial, and MTBB-Final, respectively. 96%, 98%, and 99% of images had AOM values larger than 0.9 for GBB, MTBB-Initial, and MTBB-Final, respectively. The improvement by the MTBB-Final method was statistically significant for all the evaluation measures by the Wilcoxon signed rank test (p<0.0001). Conclusions: The MTBB approach that combined dynamic multiple thresholding and gradient information provided better performance than the breast boundary

  10. Twist1 activity thresholds define multiple functions in limb development

    PubMed Central

    Krawchuk, Dayana; Weiner, Shoshana J.; Chen, You-Tzung; Lu, Benson; Costantini, Frank; Behringer, Richard R.; Laufer, Ed

    2010-01-01

    Summary The basic helix-loop-helix transcription factor Twist1 is essential for normal limb development. Twist1−/− embryos die at midgestation. However, studies on early limb buds found that Twist1−/− mutant limb mesenchyme has an impaired response to FGF signaling from the apical ectodermal ridge, which disrupts the feedback loop between the mesenchyme and AER, and reduces and shifts anteriorly Shh expression in the zone of polarizing activity. We have combined Twist1 null, hypomorph and conditional alleles to generate a Twist1 allelic series that survives to birth. As Twist1 activity is reduced, limb skeletal defects progress from preaxial polydactyly to girdle reduction combined with hypoplasia, aplasia or mirror symmetry of all limb segments. With reduced Twist1 activity there is striking and progressive upregulation of ectopic Shh expression in the anterior of the limb, combined with an anterior shift in the posterior Shh domain, which is expressed at normal intensity, and loss of the posterior AER. Consequently limb outgrowth is initially impaired, before an ectopic anterior Shh domain expands the AER, promoting additional growth and repatterning. Reducing the dosage of FGF targets of the Etv gene family, which are known repressors of Shh expression in the anterior limb mesenchyme, strongly enhances the anterior skeletal phenotype. Conversely this and other phenotypes are suppressed by reducing the dosage of the Twist1 antagonist Hand2. Our data support a model whereby multiple Twist1 activity thresholds contribute to early limb bud patterning, and suggest how particular combinations of skeletal defects result from differing amounts of Twist1 activity. PMID:20732316

  11. Modeling the Interactions Between Multiple Crack Closure Mechanisms at Threshold

    NASA Technical Reports Server (NTRS)

    Newman, John A.; Riddell, William T.; Piascik, Robert S.

    2003-01-01

    A fatigue crack closure model is developed that includes interactions between the three closure mechanisms most likely to occur at threshold; plasticity, roughness, and oxide. This model, herein referred to as the CROP model (for Closure, Roughness, Oxide, and Plasticity), also includes the effects of out-of plane cracking and multi-axial loading. These features make the CROP closure model uniquely suited for, but not limited to, threshold applications. Rough cracks are idealized here as two-dimensional sawtooths, whose geometry induces mixed-mode crack- tip stresses. Continuum mechanics and crack-tip dislocation concepts are combined to relate crack face displacements to crack-tip loads. Geometric criteria are used to determine closure loads from crack-face displacements. Finite element results, used to verify model predictions, provide critical information about the locations where crack closure occurs.

  12. Kanerva's sparse distributed memory with multiple hamming thresholds

    NASA Technical Reports Server (NTRS)

    Pohja, Seppo; Kaski, Kimmo

    1992-01-01

    If the stored input patterns of Kanerva's Sparse Distributed Memory (SDM) are highly correlated, utilization of the storage capacity is very low compared to the case of uniformly distributed random input patterns. We consider a variation of SDM that has a better storage capacity utilization for correlated input patterns. This approach uses a separate selection threshold for each physical storage address or hard location. The selection of the hard locations for reading or writing can be done in parallel of which SDM implementations can benefit.

  13. Multiple pulse thresholds in live eyes for ultrashort laser pulses in the near infrared

    NASA Astrophysics Data System (ADS)

    Stolarski, David J.; Cain, Clarence P.; Toth, Cynthia A.; Noojin, Gary D.; Rockwell, Benjamin A.

    1999-06-01

    Damage thresholds using multiple laser pulses to produce minimum visible lesions (MVL) in rhesus monkey eyes are reported for near-infrared (800 nm) at 130 femtoseconds. Previous studies by our research group using single pulses in the near-infrared (1060 nm) have determined damage thresholds and retinal spot size dependence. We report the first multiple pulse damage thresholds using femtosecond pulses. MVL thresholds at 1 hour and 24 hours postexposure were determined for 1, 100 and 1,000 pulses and we compare these with other reported multiple pulse thresholds. These new data will be added to the databank for retinal MVL's as a function of pulse repetition rate for this pulsewidth and a comparison will be made with the ANSI standard for multiple pulse exposures. Our measurements show that the retinal ED50 threshold/pulse in the paramacula decreases for increasing number of pulses. The MVL-ED50 at the threshold/pulse decreased by a factor of 4 (0.55 (mu) J to 0.13 (mu) J/pulse) for an increase from 1 to 100 pulses.

  14. Complex dynamics in biological systems arising from multiple limit cycle bifurcation.

    PubMed

    Yu, P; Lin, W

    2016-01-01

    In this paper, we study complex dynamical behaviour in biological systems due to multiple limit cycles bifurcation. We use simple epidemic and predator-prey models to show exact routes to new types of bistability, that is, bistability between equilibrium and periodic oscillation, and bistability between two oscillations, which may more realistically describe the real situations. Bifurcation theory and normal form theory are applied to investigate the multiple limit cycles bifurcating from Hopf critical point. PMID:27042877

  15. Multiple β-catenin mutations in hepatocellular lesions arising in Abernethy malformation.

    PubMed

    Sorkin, Tracy; Strautnieks, Sandra; Foskett, Pierre; Peddu, Praveen; Thompson, Richard J; Heaton, Nigel; Quaglia, Alberto

    2016-07-01

    An 18-year-old man underwent liver transplantation due to an Abernethy malformation associated with multiple hepatocellular nodules including one which was rapidly enlarging and was suspicious for malignant transformation. Analysis of the explanted liver showed a spectrum of multiple hepatocellular nodules ranging in appearance from focal nodular hyperplasia, hepatocellular adenoma and to a well-differentiated hepatocellular neoplasm borderline for hepatocellular carcinoma. Mutational analysis revealed wild-type β-catenin expression in the background liver and some nodules, whilst different variants were present in other lesions irrespective of their morphological appearance. No telomerase reverse transcriptase (TERT) promoter mutation was identified. Abernethy malformations can lead to independent genetic events which can result in β-catenin mutations associated with malignant transformation of hepatocellular nodules. When following up such patients, one must therefore have a high index of suspicion, particularly if radiological surveillance reveals a change in the nature of hepatic lesions. PMID:27038679

  16. Extensive and ulcerated malignant proliferating trichilemmal (pilar) tumour, arising from multiple, large, degenerated trichilemmal (pilar) cysts.

    PubMed

    Morgado, Bruno; Agostini, Patrick; Rivero, António; Silva, Nuno

    2016-01-01

    We report a rare case of a 61-year-old homeless man with a 15-year history of multiple trichilemmal cysts that served as a forerunner for the emergence of a malignant proliferating pilar tumour. The patient presented multiple, large, purulent, ulcerated lesions ranging from 10 to 150 mm in diameter, covering most of the scalp, with large areas superimposed by extensive myiasis infestation. The patient presented with no other major clinical findings. A CT scan showed no detectable signs of local or distant metastatic invasion. Initial supportive treatment was implemented. Given the extent of the injury, further surgical excision was considered, which required transfer to a specialised surgical centre. This social case is of educational value, as it can raise clinician awareness about the ability of trichilemmal cysts to undergo malignant transformation. Additionally, it highlights the importance of adequate social assistance structures for patients in need. PMID:26857582

  17. Multiple helical configuration and quantity threshold of graphene nanoribbons inside a single-walled carbon nanotube

    PubMed Central

    Li, Yifan; Chen, Wei; Ren, Hongru; Zhou, Xuyan; Li, Hui

    2015-01-01

    Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the π-π stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwhile its forming time is related to helical angle. The simulated threshold of GNRs in SWCNT decreases with GNR width but increases with SWCNT diameter, and two formulas have come up in this study to estimate the quantity threshold for GNRs. It has been found that multilayered graphite is hard to be stripped in SWCNT because the special helical configuration with incompletely separated GNRs is metastable. This work provides a possibility to control the configuration of GNR@SWCNT. PMID:26374276

  18. Multiple helical configuration and quantity threshold of graphene nanoribbons inside a single-walled carbon nanotube.

    PubMed

    Li, Yifan; Chen, Wei; Ren, Hongru; Zhou, Xuyan; Li, Hui

    2015-01-01

    Molecular dynamics simulation has been carried out to explore the configuration and quantity threshold of multiple graphene nanoribbons (GNRs) in single-walled carbon nanotube (SWCNT). The simulation results showed that several GNRs tangled together to form a perfect spiral structure to maximize the π-π stacking area when filling inside SWCNT. The formation of multiple helical configuration is influenced by the combined effect of structure stability, initial arrangement and tube space, meanwhile its forming time is related to helical angle. The simulated threshold of GNRs in SWCNT decreases with GNR width but increases with SWCNT diameter, and two formulas have come up in this study to estimate the quantity threshold for GNRs. It has been found that multilayered graphite is hard to be stripped in SWCNT because the special helical configuration with incompletely separated GNRs is metastable. This work provides a possibility to control the configuration of GNR@SWCNT. PMID:26374276

  19. Dispersion-flattened-fiber based optical thresholder for multiple-access-interference suppression in OCDMA system.

    PubMed

    Wang, Xu; Hamanaka, Taro; Wada, Naoya; Kitayama, Ken-Ichi

    2005-07-11

    An optical thresholding technique based on super-continuum generation in dispersion flattened fiber is proposed and experimentally demonstrated to enable data-rate detection in optical code division multiple access networks. The proposed scheme exhibits an excellent discrimination between a desired signal and interference signals with features of pulse reshaping, low insertion loss, polarization independency as well as reasonable operation power. PMID:19498545

  20. Synergy of adaptive thresholds and multiple transmitters in free-space optical communication.

    PubMed

    Louthain, James A; Schmidt, Jason D

    2010-04-26

    Laser propagation through extended turbulence causes severe beam spread and scintillation. Airborne laser communication systems require special considerations in size, complexity, power, and weight. Rather than using bulky, costly, adaptive optics systems, we reduce the variability of the received signal by integrating a two-transmitter system with an adaptive threshold receiver to average out the deleterious effects of turbulence. In contrast to adaptive optics approaches, systems employing multiple transmitters and adaptive thresholds exhibit performance improvements that are unaffected by turbulence strength. Simulations of this system with on-off-keying (OOK) showed that reducing the scintillation variations with multiple transmitters improves the performance of low-frequency adaptive threshold estimators by 1-3 dB. The combination of multiple transmitters and adaptive thresholding provided at least a 10 dB gain over implementing only transmitter pointing and receiver tilt correction for all three high-Rytov number scenarios. The scenario with a spherical-wave Rytov number R=0.20 enjoyed a 13 dB reduction in the required SNR for BER's between 10(-5) to 10(-3), consistent with the code gain metric. All five scenarios between 0.06 and 0.20 Rytov number improved to within 3 dB of the SNR of the lowest Rytov number scenario. PMID:20588740

  1. A novel EMD selecting thresholding method based on multiple iteration for denoising LIDAR signal

    NASA Astrophysics Data System (ADS)

    Li, Meng; Jiang, Li-hui; Xiong, Xing-long

    2015-06-01

    Empirical mode decomposition (EMD) approach has been believed to be potentially useful for processing the nonlinear and non-stationary LIDAR signals. To shed further light on its performance, we proposed the EMD selecting thresholding method based on multiple iteration, which essentially acts as a development of EMD interval thresholding (EMD-IT), and randomly alters the samples of noisy parts of all the corrupted intrinsic mode functions to generate a better effect of iteration. Simulations on both synthetic signals and LIDAR signals from real world support this method.

  2. Hearing thresholds of a harbor porpoise (Phocoena phocoena) for playbacks of multiple pile driving strike sounds.

    PubMed

    Kastelein, Ronald A; Hoek, Lean; Gransier, Robin; de Jong, Christ A F

    2013-09-01

    Pile driving is presently the most common method used to attach wind turbines to the sea bed. To assess the impact of pile driving sounds on harbor porpoises, it is important to know at what distance these sounds can be detected. Using a psychophysical technique, a male porpoise's hearing thresholds were obtained for series of five pile driving sounds (inter-pulse interval 1.2-1.3 s) recorded at 100 and 800 m from the pile driving site, and played back in a pool. The 50% detection threshold sound exposure levels (SELs) for the first sound of the series (no masking) were 72 (100 m) and 74 (800 m) dB re 1 μPa(2)s. Multiple sounds in succession (series) caused a ~5 dB decrease in hearing threshold; the mean 50% detection threshold SELs for any sound in the series were 68 (100 m) and 69 (800 m) dB re 1 μPa(2)s. Depending on the actual propagation conditions and background noise levels, the results suggest that pile driving sounds are audible to porpoises at least at tens of kilometers from pile driving sites. PMID:23967960

  3. ARISE antenna

    NASA Astrophysics Data System (ADS)

    Chmielewski, Arthur B.; Noca, Muriel; Ulvestad, James

    2000-03-01

    Supermassive black holes are among the most spectacular objects in the Universe, and are laboratories for physics in extreme conditions. Understanding the physics of massive black holes and related phenomena is a primary goal of the ARISE mission. The scientific goals of the mission are described in detail on the ARISE web site http://arise.ipl.nasa.gov and in the ARISE Science Goals document. The following paper, as the title suggests, is not intended to be a comprehensive description of ARISE, but deals only with one aspect of the ARISE mission-the inflatable antenna which is the key element of the ARISE spacecraft. This spacecraft,due to the extensive reliance on inflatables, may be considered as the first generation Gossamer spacecraft

  4. T1- Thresholds in Black Holes Increase Clinical-Radiological Correlation in Multiple Sclerosis Patients

    PubMed Central

    Thaler, Christian; Faizy, Tobias; Sedlacik, Jan; Holst, Brigitte; Stellmann, Jan-Patrick; Young, Kim Lea; Heesen, Christoph; Fiehler, Jens; Siemonsen, Susanne

    2015-01-01

    Background Magnetic Resonance Imaging (MRI) is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS). While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH)) have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation. Objective We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT) thresholds to achieve best possible correlation between BH lesion volume and clinical disability. Method 40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR), magnetization-prepared rapid gradient echo (MPRAGE) before and after Gadolinium (GD) injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE) sequences. BHs (BHvis) were marked by two raters on native T1-weighted (T1w)-MPRAGE, contrast-enhancing lesions (CE lesions) on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions) were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX) were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite) and lesion volume were determined for different T1-RT thresholds. Results Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p<0.05). Significant correlations between BHvis/total-FLAIR lesion volume and clinical disability were obtained for a wide range of T1-RT thresholds. The highest correlation for BHvis and total-FLAIR lesion masks were found at T1-RT>1500 ms

  5. Damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses: theoretical and experimental study

    NASA Astrophysics Data System (ADS)

    Meng, Qinglong; Zhang, Bin; Zhong, Sencheng; Zhu, Liguo

    2016-06-01

    The damage threshold of lithium niobate crystal under single and multiple femtosecond laser pulses has been studied theoretically and experimentally. Firstly, the model for the damage threshold prediction of crystal materials based on the improved rate equation has been proposed. Then, the experimental measure method of the damage threshold of crystal materials has been given in detail. On the basis, the variation of the damage threshold of lithium niobate crystal with the pulse duration has also been analyzed quantitatively. Finally, the damage threshold of lithium niobate crystal under multiple laser pulses has been measured and compared to the theoretical results. The results show that the transmittance of lithium niobate crystal is almost a constant when the laser pulse fluence is relative low, whereas it decreases linearly with the increase in the laser pulse fluence below the damage threshold. The damage threshold of lithium niobate crystal increases with the increase in the duration of the femtosecond laser pulse. And the damage threshold of lithium niobate crystal under multiple laser pulses is obviously lower than that irradiated by a single laser pulse. The theoretical data fall in good agreement with the experimental results.

  6. Environmental signals elicit multiple responses in dorsal telencephalic progenitors by threshold-dependent mechanisms.

    PubMed

    Lillien, Laura; Gulacsi, Alexandra

    2006-07-01

    Environmental signals including epidermal growth factor family members, Shh, fibroblast growth factor, and bone morphogenetic protein (BMP) can affect multiple processes during the development of the central nervous system, raising questions about the mechanisms that determine how these pleiotropic signals are interpreted to elicit appropriate responses at specific times and locations. Here we address the idea that different thresholds of stimulation determine how progenitors in the dorsal telencephalon interpret these signals. One mechanism for achieving different thresholds of signaling is illustrated by the developmental increase in the level of epidermal growth factor receptor (EGFR) expression among a subset of progenitors in the late embryonic telencephalon. Another mechanism is illustrated by the antagonistic interaction of BMP with Shh, which can influence EGFR expression and neuron subtype choice. We focus on the similarities and differences in the control of these responses and address the possibility that the gamma-aminobutyric acidergic neuron specification might be linked to progenitor expression of a higher level of EGFRs. PMID:16766711

  7. Multiple pulse thermal damage thresholds of materials for x-ray free electron laser optics investigated with an ultraviolet laser

    SciTech Connect

    Hau-Riege, Stefan P.; London, Richard A.; Bionta, Richard M.; Soufli, Regina; Ryutov, Dmitri; Shirk, Michael; Baker, Sherry L.; Smith, Patrick M.; Nataraj, Pradeep

    2008-11-17

    Optical elements to be used for x-ray free electron lasers (XFELs) must withstand multiple high-fluence pulses. We have used an ultraviolet laser to study the damage of two candidate materials, crystalline Si and B{sub 4}C-coated Si, emulating the temperature profile expected to occur in optics exposed to XFEL pulses. We found that the damage threshold for 10{sup 5} pulses is {approx}20% to 70% lower than the melting threshold.

  8. A vertical-energy-thresholding procedure for data reduction with multiple complex curves.

    PubMed

    Jung, Uk; Jeong, Myong K; Lu, Jye-Chyi

    2006-10-01

    Due to the development of sensing and computer technology, measurements of many process variables are available in current manufacturing processes. It is very challenging, however, to process a large amount of information in a limited time in order to make decisions about the health of the processes and products. This paper develops a "preprocessing" procedure for multiple sets of complicated functional data in order to reduce the data size for supporting timely decision analyses. The data type studied has been used for fault detection, root-cause analysis, and quality improvement in such engineering applications as automobile and semiconductor manufacturing and nanomachining processes. The proposed vertical-energy-thresholding (VET) procedure balances the reconstruction error against data-reduction efficiency so that it is effective in capturing key patterns in the multiple data signals. The selected wavelet coefficients are treated as the "reduced-size" data in subsequent analyses for decision making. This enhances the ability of the existing statistical and machine-learning procedures to handle high-dimensional functional data. A few real-life examples demonstrate the effectiveness of our proposed procedure compared to several ad hoc techniques extended from single-curve-based data modeling and denoising procedures. PMID:17036818

  9. Modeling of Beams’ Multiple-Contact Mode with an Application in the Design of a High-g Threshold Microaccelerometer

    PubMed Central

    Li, Kai; Chen, Wenyuan; Zhang, Weiping

    2011-01-01

    Beam’s multiple-contact mode, characterized by multiple and discrete contact regions, non-uniform stoppers’ heights, irregular contact sequence, seesaw-like effect, indirect interaction between different stoppers, and complex coupling relationship between loads and deformation is studied. A novel analysis method and a novel high speed calculation model are developed for multiple-contact mode under mechanical load and electrostatic load, without limitations on stopper height and distribution, providing the beam has stepped or curved shape. Accurate values of deflection, contact load, contact region and so on are obtained directly, with a subsequent validation by CoventorWare. A new concept design of high-g threshold microaccelerometer based on multiple-contact mode is presented, featuring multiple acceleration thresholds of one sensitive component and consequently small sensor size. PMID:22163897

  10. When does female multiple mating evolve to adjust inbreeding? Effects of inbreeding depression, direct costs, mating constraints, and polyandry as a threshold trait.

    PubMed

    Duthie, A Bradley; Bocedi, Greta; Reid, Jane M

    2016-09-01

    Polyandry is often hypothesized to evolve to allow females to adjust the degree to which they inbreed. Multiple factors might affect such evolution, including inbreeding depression, direct costs, constraints on male availability, and the nature of polyandry as a threshold trait. Complex models are required to evaluate when evolution of polyandry to adjust inbreeding is predicted to arise. We used a genetically explicit individual-based model to track the joint evolution of inbreeding strategy and polyandry defined as a polygenic threshold trait. Evolution of polyandry to avoid inbreeding only occurred given strong inbreeding depression, low direct costs, and severe restrictions on initial versus additional male availability. Evolution of polyandry to prefer inbreeding only occurred given zero inbreeding depression and direct costs, and given similarly severe restrictions on male availability. However, due to its threshold nature, phenotypic polyandry was frequently expressed even when strongly selected against and hence maladaptive. Further, the degree to which females adjusted inbreeding through polyandry was typically very small, and often reflected constraints on male availability rather than adaptive reproductive strategy. Evolution of polyandry solely to adjust inbreeding might consequently be highly restricted in nature, and such evolution cannot necessarily be directly inferred from observed magnitudes of inbreeding adjustment. PMID:27464756

  11. Regime shifts, thresholds and multiple stable states in freshwater ecosystems; a critical appraisal of the evidence.

    PubMed

    Capon, Samantha J; Lynch, A Jasmyn J; Bond, Nick; Chessman, Bruce C; Davis, Jenny; Davidson, Nick; Finlayson, Max; Gell, Peter A; Hohnberg, David; Humphrey, Chris; Kingsford, Richard T; Nielsen, Daryl; Thomson, James R; Ward, Keith; Mac Nally, Ralph

    2015-11-15

    The concepts of ecosystem regime shifts, thresholds and alternative or multiple stable states are used extensively in the ecological and environmental management literature. When applied to aquatic ecosystems, these terms are used inconsistently reflecting differing levels of supporting evidence among ecosystem types. Although many aquatic ecosystems around the world have become degraded, the magnitude and causes of changes, relative to the range of historical variability, are poorly known. A working group supported by the Australian Centre for Ecological Analysis and Synthesis (ACEAS) reviewed 135 papers on freshwater ecosystems to assess the evidence for pressure-induced non-linear changes in freshwater ecosystems; these papers used terms indicating sudden and non-linear change in their titles and key words, and so was a positively biased sample. We scrutinized papers for study context and methods, ecosystem characteristics and focus, types of pressures and ecological responses considered, and the type of change reported (i.e., gradual, non-linear, hysteretic or irreversible change). There was little empirical evidence for regime shifts and changes between multiple or alternative stable states in these studies although some shifts between turbid phytoplankton-dominated states and clear-water, macrophyte-dominated states were reported in shallow lakes in temperate climates. We found limited understanding of the subtleties of the relevant theoretical concepts and encountered few mechanistic studies that investigated or identified cause-and-effect relationships between ecological responses and nominal pressures. Our results mirror those of reviews for estuarine, nearshore and marine aquatic ecosystems, demonstrating that although the concepts of regime shifts and alternative stable states have become prominent in the scientific and management literature, their empirical underpinning is weak outside of a specific environmental setting. The application of these

  12. Multiple-level threshold switching behavior of In2Se3 confined in a nanostructured silicon substrate

    NASA Astrophysics Data System (ADS)

    Lee, Jae Young; Sun, Ke; Li, Biyun; Xie, Ya-Hong; Wei, Xinyu; Russell, Thomas P.

    2010-08-01

    We report the experimental observation of an intriguing behavior of multiple-level threshold switching of Si-In2Se3 heterojunction devices consisting of high-density arrays of sharp points of nanometer radius of curvature. Comparison with devices of similar junction area but without the sharp points shows that the multiple-level switching behavior is unique to devices with junctions consisting of sharp points.

  13. Cooperative Spectrum Sensing with Multiple Antennas Using Adaptive Double-Threshold Based Energy Detector in Cognitive Radio Networks

    NASA Astrophysics Data System (ADS)

    Bagwari, A.; Tomar, G. S.

    2014-04-01

    In Cognitive radio networks, spectrum sensing is used to sense the unused spectrum in an opportunistic manner. In this paper, multiple antennas based energy detector utilizing adaptive double-threshold for spectrum sensing is proposed, which enhances detection performance and overcomes sensing failure problem as well. The detection threshold is made adaptive to the fluctuation of the received signal power in each local detector of cognitive radio (CR) user. Numerical results show that by using multiple antennas at the CRs, it is possible to significantly improve detection performance at very low signal-to-noise ratio (SNR). Further, the scheme was analyzed in conjunction with cooperative spectrum sensing (CSS), where CRs utilize selection combining of the decision statistics obtained by an adaptive double-threshold energy detector for making a binary decision of the presence or absence of a primary user. The decision of each CR is forwarded over error free orthogonal channels to the fusion centre, which takes the final decision of a spectrum hole. It is further found that CSS with multiple antenna-based energy detector with adaptive double-threshold improves detection performance around 26.8 % as compared to hierarchical with quantization method at -12 dB SNR, under the condition that a small number of sensing nodes are used in spectrum sensing.

  14. The generalization of Lu-Fano plot for multi-channel atomic spectra with multiple ionization thresholds

    NASA Astrophysics Data System (ADS)

    Gao, Xiang; Jin, Rui; Han, Xiao-Ying; Li, Jia-Ming

    2015-05-01

    Understanding the detailed dynamics of electron-ion interactions is of fundamental importance in the fields of astrophysics and so on. It's important to provide the related atomic data with accuracies determined. Using our modified R-matrix code R-Eigen, we can directly calculate the short-range scattering matrices corresponding to the physical parameters associated with the multichannel quantum defect theory (MQDT) for both the discrete and continuous energy regions. Various physical quantities can then be derived from a straightforward application of the MQDT procedure. Through analytical continuation properties of short-range scattering matrices, we demonstrated that the precisions of scattering calculations can be determined readily in a systematical way by using the Lu-Fano plot for Kr atom with two ionization thresholds. We will show our studies of the graphical representations of the MQDT solutions of atomic spectra with multiple ionization thresholds, which is a generalization of Lu-Fano plot for the cases with two thresholds. In this way, we can determine the related scattering calculation precisions by using the spectroscopic data for general atoms with multiple ionization thresholds. We can also elucidate the intimate relations between the discrete energy levels and adjacent resonant autoionization spectra. National Natural Science Foundation of China (Grant No. 11274035).

  15. Multiple Velocity Components of Narrow-lined Absorption Arising from the Ejecta of AG Car, P Cyg, and Eta Car.

    NASA Astrophysics Data System (ADS)

    Vieira Kober, Gladys; Gull, T. R.; Bruhweiler, F.; Nielsen, K. E.; Hill, G.

    2007-12-01

    Luminous Blue Variables (LBVs) are a small group of massive objects, with a past characterized by occasional outbursts. Well known members in our galaxy are Eta Car, AG Car, HR Car and P Cyg. HST/STIS observations of Eta Car show a very complex and rich circumstellar absorption spectrum. Of the 20 distinct absorption systems, the ionized strong absorber at -146 km/s (Little Homunculus) shows lines from transitions originating from mainly singly ionized iron-group elements. Curve-of-growth analysis for Fe II lines plus photo-ionization and statistical equilibrium modeling indicated a temperature Te = 6400 K and density n 5x107 cm-3. AG Car and P Cyg have, like Eta Car, circumstellar nebulae which likely are remnants of typical LBV mass loss events. Spectral analysis of high resolution VLT/UVES data for AG Car and Keck/HIRES data for P Cyg also reveal multiple narrow absorption components with excitation and velocities similar to Eta Car's Little Homunculus. In this poster we present curve-of-growth analysis for Fe II lines for the narrow components around AG Car and P Cyg, and temperature estimates based on level populations for these absorbers. We compare the absorbing features around these three LBVs, providing clues to wind structures and ejections for these massive stars. We thank NASA, STScI, Keck and ESO for providing resources and spectra analyzed in this poster, recorded with HST/STIS, Keck/HIRES and VLT/UVES.

  16. STATISTICAL METHODOLOGY FOR THE SIMULTANEOUS ANALYSIS OF MULTIPLE TYPES OF OUTCOMES IN NONLINEAR THRESHOLD MODELS.

    EPA Science Inventory

    Multiple outcomes are often measured on each experimental unit in toxicology experiments. These multiple observations typically imply the existence of correlation between endpoints, and a statistical analysis that incorporates it may result in improved inference. When both disc...

  17. An approach to estimate the areal rain-rate distribution from spaceborne radar by the use of multiple thresholds

    NASA Technical Reports Server (NTRS)

    Meneghini, R.; Jones, J. A.

    1993-01-01

    Estimates of rain rate derived from a spaceborne weather radar will be most reliable over an intermediate range of values. In forming an area average of the rain rate, an alternative to the averaging of the high-resolution estimates, irrespective of their individual accuracies, is a multiple threshold approach. The method is based on the fact that the fractional area above a particular rain-rate threshold R(j) is related to the cumulative distribution of rain rates evaluated at R(j). Varying the threshold over the effective dynamic range of the radar yields the cumulative distribution function over this range. To obtain the distribution at all rain rates, a lognormal or gamma test function is selected such that the mean-square error between the test function and the measured values is minimized. Once the unknown parameters are determined, the first-order statistics of the areawide rain-rate distribution can be found. Tests of the method with data from the SPANDAR radar provide comparisons between it and the single threshold and the direct averaging approaches.

  18. A Primary Cutaneous CD30-Positive T-Cell Lymphoproliferative Disorder Arising in a Patient With Multiple Myeloma and Cutaneous Amyloidosis.

    PubMed

    Romano, Ryan C; Cohen, Daniel N; Howard, Matthew T; Wieland, Carilyn N

    2016-05-01

    CD30-positive cutaneous lymphoproliferative disorders, a group of T-cell neoplasms, including lymphomatoid papulosis (LyP) and cutaneous anaplastic large cell lymphoma, require careful clinicopathologic correlation for diagnosis. An association between LyP and the development of a second hematolymphoid malignancy has been established in the literature. LyP has also been reported with systemic amyloidosis, but no such reports have documented coexisting cutaneous amyloid deposition with LyP to our knowledge. A 66-year-old woman with cutaneous amyloidosis, secondary to multiple myeloma, in remission, presented with erythematous and dark-brown papules involving the right arm, scalp, and torso. Punch biopsy of the arm showed a dermal infiltrate of intermediate-sized lymphocytes, some of which displayed a plasmacytoid morphology and prominent nodular subepidermal amyloid deposition. Punch biopsy of the scalp similarly showed a nonepidermotropic dense dermal infiltrate of intermediate-sized plasmacytoid lymphocytes and multifocal amyloid deposition. Both infiltrates were immunophenotypically CD30-positive, anaplastic lymphoma kinase-negative T-cell lymphoproliferative processes. Subsequent studies showed no systemic involvement, and clinical correlation suggested a final diagnosis of LyP. We present this case of LyP, which histologically mimics a B-cell proliferation with a plasmacytoid morphology arising in association with cutaneous amyloidosis to highlight the importance of clinicopathologic correlation, a thorough battery of immunohistochemical studies, and consideration for a second hematologic malignancy arising in the setting of LyP. PMID:26981738

  19. Hearing thresholds of two harbor seals (Phoca vitulina) for playbacks of multiple pile driving strike sounds.

    PubMed

    Kastelein, Ronald A; Hoek, Lean; Gransier, Robin; Jennings, Nancy

    2013-09-01

    Pile driving, which creates high amplitude sounds with potentially negative impacts on the marine environment, is used to attach wind turbines to the sea bed. To quantify the distance at which pile driving sounds can be detected by harbor seals, unmasked hearing thresholds were obtained for series of five pile driving sounds recorded at 100 and 800 m from a pile driving location. The played back spectra resembled the spectra of sounds recorded under certain conditions 10-50 km from an offshore pile driving site. The lower the received level, the later within the series of sounds the harbor seals responded. The mean 50% detection threshold sound exposure levels for any sound in the series were: 40 (seal 01, 100 m), 39 (seal 01, 800 m), 43 (seal 02, 100 m), and 43 (seal 02, 800 m) dB re 1 μPa(2)s (add 9 dB for sound pressure level, dB re 1 μPa). The mean 50% detection thresholds based on detection of only the first sound of the series were ca. 5 dB higher. Detection at sea depends on the actual propagation conditions and on the degree of masking of the sounds by ambient noise, but the present study suggests that pile driving sounds are audible to harbor seals up to hundreds of kilometers from pile driving sites. PMID:23967961

  20. Active Learning and Threshold Concepts in Multiple Testing That Can Further Develop Student Critical Statistical Thinking

    ERIC Educational Resources Information Center

    White, Desley

    2015-01-01

    Two practical activities are described, which aim to support critical thinking about statistics as they concern multiple outcomes testing. Formulae are presented in Microsoft Excel spreadsheets, which are used to calculate the inflation of error associated with the quantity of tests performed. This is followed by a decision-making exercise, where…

  1. A varying threshold method for ChIP peak-calling using multiple sources of information

    PubMed Central

    Chen, Kuan-Bei; Zhang, Yu

    2010-01-01

    Motivation: Gene regulation commonly involves interaction among DNA, proteins and biochemical conditions. Using chromatin immunoprecipitation (ChIP) technologies, protein–DNA interactions are routinely detected in the genome scale. Computational methods that detect weak protein-binding signals and simultaneously maintain a high specificity yet remain to be challenging. An attractive approach is to incorporate biologically relevant data, such as protein co-occupancy, to improve the power of protein-binding detection. We call the additional data related with the target protein binding as supporting tracks. Results: We propose a novel but rigorous statistical method to identify protein occupancy in ChIP data using multiple supporting tracks (PASS2). We demonstrate that utilizing biologically related information can significantly increase the discovery of true protein-binding sites, while still maintaining a desired level of false positive calls. Applying the method to GATA1 restoration in mouse erythroid cell line, we detected many new GATA1-binding sites using GATA1 co-occupancy data. Availability: http://stat.psu.edu/∼yuzhang/pass2.tar Contact: yuzhang@stat.psu.edu PMID:20823314

  2. Multiple-Threshold Event Detection and Other Enhancements to the Virtual Seismologist (VS) Earthquake Early Warning Algorithm

    NASA Astrophysics Data System (ADS)

    Fischer, M.; Caprio, M.; Cua, G. B.; Heaton, T. H.; Clinton, J. F.; Wiemer, S.

    2009-12-01

    The Virtual Seismologist (VS) algorithm is a Bayesian approach to earthquake early warning (EEW) being implemented by the Swiss Seismological Service at ETH Zurich. The application of Bayes’ theorem in earthquake early warning states that the most probable source estimate at any given time is a combination of contributions from a likelihood function that evolves in response to incoming data from the on-going earthquake, and selected prior information, which can include factors such as network topology, the Gutenberg-Richter relationship or previously observed seismicity. The VS algorithm was one of three EEW algorithms involved in the California Integrated Seismic Network (CISN) real-time EEW testing and performance evaluation effort. Its compelling real-time performance in California over the last three years has led to its inclusion in the new USGS-funded effort to develop key components of CISN ShakeAlert, a prototype EEW system that could potentially be implemented in California. A significant portion of VS code development was supported by the SAFER EEW project in Europe. We discuss recent enhancements to the VS EEW algorithm. We developed and continue to test a multiple-threshold event detection scheme, which uses different association / location approaches depending on the peak amplitudes associated with an incoming P pick. With this scheme, an event with sufficiently high initial amplitudes can be declared on the basis of a single station, maximizing warning times for damaging events for which EEW is most relevant. Smaller, non-damaging events, which will have lower initial amplitudes, will require more picks to be declared an event to reduce false alarms. This transforms the VS codes from a regional EEW approach reliant on traditional location estimation (and it requirement of at least 4 picks as implemented by the Binder Earthworm phase associator) to a hybrid on-site/regional approach capable of providing a continuously evolving stream of EEW

  3. Radiation Treatment Planning Using Positron Emission and Computed Tomography for Lung and Pharyngeal Cancers: A Multiple-Threshold Method for [{sup 18}F]Fluoro-2-Deoxyglucose Activity

    SciTech Connect

    Okubo, Mitsuru; Nishimura, Yasumasa; Nakamatsu, Kiyoshi; Okumura, Masahiko R.T.; Shibata, Toru; Kanamori, Shuichi; Hanaoka, Kouhei R.T.; Hosono, Makoto

    2010-06-01

    Purpose: Clinical applicability of a multiple-threshold method for [{sup 18}F]fluoro-2-deoxyglucose (FDG) activity in radiation treatment planning was evaluated. Methods and Materials: A total of 32 patients who underwent positron emission and computed tomography (PET/CT) simulation were included; 18 patients had lung cancer, and 14 patients had pharyngeal cancer. For tumors of <=2 cm, 2 to 5 cm, and >5 cm, thresholds were defined as 2.5 standardized uptake value (SUV), 35%, and 20% of the maximum FDG activity, respectively. The cervical and mediastinal lymph nodes with the shortest axial diameter of >=10 mm were considered to be metastatic on CT (LNCT). The retropharyngeal lymph nodes with the shortest axial diameter of >=5 mm on CT and MRI were also defined as metastatic. Lymph nodes showing maximum FDG activity greater than the adopted thresholds for radiation therapy planning were designated LNPET-RTP, and lymph nodes with a maximum FDG activity of >=2.5 SUV were regarded as malignant and were designated LNPET-2.5 SUV. Results: The sizes of gross tumor volumes on PET (GTVPET) with the adopted thresholds in the axial plane were visually well fitted to those of GTV on CT (GTVCT). However, the volumes of GTVPET were larger than those of GTVCT, with significant differences (p < 0.0001) for lung cancer, due to respiratory motion. For lung cancer, the numbers of LNCT, LNPET-RTP, and LNPET-2.5 SUV were 29, 28, and 34, respectively. For pharyngeal cancer, the numbers of LNCT, LNPET-RTP, and LNPET-2.5 SUV were 14, 9, and 15, respectively. Conclusions: Our multiple thresholds were applicable for delineating the primary target on PET/CT simulation. However, these thresholds were inaccurate for depicting malignant lymph nodes.

  4. The Physics of Protoplanetesimal Dust Agglomerates. V. Multiple Impacts of Dusty Agglomerates at Velocities Above the Fragmentation Threshold

    NASA Astrophysics Data System (ADS)

    Kothe, Stefan; Güttler, Carsten; Blum, Jürgen

    2010-12-01

    In recent years, a number of new experiments have advanced our knowledge on the early growth phases of protoplanetary dust aggregates. Some of these experiments have shown that collisions between porous and compacted agglomerates at velocities above the fragmentation threshold velocity can lead to growth of the compact body, when the porous collision partner fragments upon impact and transfers mass to the compact agglomerate. To obtain a deeper understanding of this potentially important growth process, we performed laboratory and drop tower experiments to study multiple impacts of small, highly porous dust-aggregate projectiles onto sintered dust targets. The projectile and target consisted of 1.5 μm monodisperse, spherical SiO2 monomers with volume filling factors of 0.15 ± 0.01 and 0.45 ± 0.05, respectively. The fragile projectiles were accelerated by a solenoid magnet and combined with a projectile magazine with which 25 impacts onto the same spot on the target could be performed in vacuum. We measured the mass-accretion efficiency and the volume filling factor for different impact velocities between 1.5 and 6.0 m s^{-1}. The experiments at the lowest impact speeds were performed in the Bremen drop tower under microgravity conditions to allow partial mass transfer also for the lowest adhesion case. Within this velocity range, we found a linear increase of the accretion efficiency with increasing velocity. In the laboratory experiments, the accretion efficiency increases from 0.12 to 0.21 in units of the projectile mass. The recorded images of the impacts showed that the mass transfer from the projectile to the target leads to the growth of a conical structure on the target after less than 100 impacts. From the images, we also measured the volume filling factors of the grown structures, which ranged from 0.15 (uncompacted) to 0.40 (significantly compacted) with increasing impact speed. The velocity dependency of the mass-transfer efficiency and the packing

  5. Reversal of Refractory Ulcerative Colitis and Severe Chronic Fatigue Syndrome Symptoms Arising from Immune Disturbance in an HLA-DR/DQ Genetically Susceptible Individual with Multiple Biotoxin Exposures.

    PubMed

    Gunn, Shelly R; Gunn, G Gibson; Mueller, Francis W

    2016-01-01

    BACKGROUND Patients with multisymptom chronic conditions, such as refractory ulcerative colitis (RUC) and chronic fatigue syndrome (CFS), present diagnostic and management challenges for clinicians, as well as the opportunity to recognize and treat emerging disease entities. In the current case we report reversal of co-existing RUC and CFS symptoms arising from biotoxin exposures in a genetically susceptible individual. CASE REPORT A 25-year-old previously healthy male with new-onset refractory ulcerative colitis (RUC) and chronic fatigue syndrome (CFS) tested negative for autoimmune disease biomarkers. However, urine mycotoxin panel testing was positive for trichothecene group and air filter testing from the patient's water-damaged rental house identified the toxic mold Stachybotrys chartarum. HLA-DR/DQ testing revealed a multisusceptible haplotype for development of chronic inflammation, and serum chronic inflammatory response syndrome (CIRS) biomarker testing was positive for highly elevated TGF-beta and a clinically undetectable level of vasoactive intestinal peptide (VIP). Following elimination of biotoxin exposures, VIP replacement therapy, dental extractions, and implementation of a mind body intervention-relaxation response (MBI-RR) program, the patient's symptoms resolved. He is off medications, back to work, and resuming normal exercise. CONCLUSIONS This constellation of RUC and CFS symptoms in an HLA-DR/DQ genetically susceptible individual with biotoxin exposures is consistent with the recently described CIRS disease pathophysiology. Chronic immune disturbance (turbatio immuno) can be identified with clinically available CIRS biomarkers and may represent a treatable underlying disease etiology in a subset of genetically susceptible patients with RUC, CFS, and other immune disorders. PMID:27165859

  6. Reversal of Refractory Ulcerative Colitis and Severe Chronic Fatigue Syndrome Symptoms Arising from Immune Disturbance in an HLADR/DQ Genetically Susceptible Individual with Multiple Biotoxin Exposures

    PubMed Central

    Gunn, Shelly R.; Gibson Gunn, G.; Mueller, Francis W.

    2016-01-01

    Patient: Male, 25 Final Diagnosis: Ulcerative colitis and chronic fatigue syndrome Symptoms: Colitis • profound fatigue • multi-joint pain • cognitive impairment • corneal keratitis Medication: — Clinical Procedure: VIP replacement therapy Specialty: Family Medicine Objective: Unusual clinical course Background: Patients with multisymptom chronic conditions, such as refractory ulcerative colitis (RUC) and chronic fatigue syndrome (CFS), present diagnostic and management challenges for clinicians, as well as the opportunity to recognize and treat emerging disease entities. In the current case we report reversal of co-existing RUC and CFS symptoms arising from biotoxin exposures in a genetically susceptible individual. Case Report: A 25-year-old previously healthy male with new-onset refractory ulcerative colitis (RUC) and chronic fatigue syndrome (CFS) tested negative for autoimmune disease biomarkers. However, urine mycotoxin panel testing was positive for trichothecene group and air filter testing from the patient’s water-damaged rental house identified the toxic mold Stachybotrys chartarum. HLA-DR/DQ testing revealed a multisusceptible haplotype for development of chronic inflammation, and serum chronic inflammatory response syndrome (CIRS) biomarker testing was positive for highly elevated TGF-beta and a clinically undetectable level of vasoactive intestinal peptide (VIP). Following elimination of biotoxin exposures, VIP replacement therapy, dental extractions, and implementation of a mind body intervention-relaxation response (MBI-RR) program, the patient’s symptoms resolved. He is off medications, back to work, and resuming normal exercise. Conclusions: This constellation of RUC and CFS symptoms in an HLA-DR/DQ genetically susceptible individual with biotoxin exposures is consistent with the recently described CIRS disease pathophysiology. Chronic immune disturbance (turbatio immuno) can be identified with clinically available CIRS biomarkers and

  7. Unusual complication of multiple splenic abscesses arising from a feeding jejunostomy tube subsequent to total gastrectomy: A case report and literature review

    PubMed Central

    AN, SHUCHANG; LI, BING; CUI, RONG; YAN, FENG; YANG, GUOSHAN; ZHAO, LI; ZHANG, ZHENYA; WANG, RUIQIN

    2015-01-01

    Splenic abscess is a rare clinical entity. The present study reports a case of a patient that suffered from splenic abscess secondary to septicemia resulting from Klebsiella pneumoniae infection following the removal of the feeding jejunostomy tube that was utilized subsequent to the patient undergoing total gastrectomy as part of the treatment regimen for gastric adenocarcinoma. The early clinical presentation was nonspecific and multiple splenic abscesses were subsequently identified. To reduce the risks of an additional surgical procedure in this particular patient, laparoscopic assisted splenotomy and catheter drainage were performed. Due to the severe complications that occurred in the present patient, no adjuvant chemotherapy was administered. Therefore, the unusual complication of splenic abscess subsequent to total gastrectomy should be noted, and the routine feeding jejunostomy tube placement at the time of total gastrectomy should be discussed and re-assessed. PMID:26137078

  8. Ground-water vulnerability to nitrate contamination at multiple thresholds in the mid-Atlantic region using spatial probability models

    USGS Publications Warehouse

    Greene, Earl A.; LaMotte, Andrew E.; Cullinan, Kerri-Ann

    2005-01-01

    The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency?s Regional Vulnerability Assessment Program, has developed a set of statistical tools to support regional-scale, ground-water quality and vulnerability assessments. The Regional Vulnerability Assessment Program?s goals are to develop and demonstrate approaches to comprehensive, regional-scale assessments that effectively inform managers and decision-makers as to the magnitude, extent, distribution, and uncertainty of current and anticipated environmental risks. The U.S. Geological Survey is developing and exploring the use of statistical probability models to characterize the relation between ground-water quality and geographic factors in the Mid-Atlantic Region. Available water-quality data obtained from U.S. Geological Survey National Water-Quality Assessment Program studies conducted in the Mid-Atlantic Region were used in association with geographic data (land cover, geology, soils, and others) to develop logistic-regression equations that use explanatory variables to predict the presence of a selected water-quality parameter exceeding a specified management concentration threshold. The resulting logistic-regression equations were transformed to determine the probability, P(X), of a water-quality parameter exceeding a specified management threshold. Additional statistical procedures modified by the U.S. Geological Survey were used to compare the observed values to model-predicted values at each sample point. In addition, procedures to evaluate the confidence of the model predictions and estimate the uncertainty of the probability value were developed and applied. The resulting logistic-regression models were applied to the Mid-Atlantic Region to predict the spatial probability of nitrate concentrations exceeding specified management thresholds. These thresholds are usually set or established by regulators or managers at National or local levels. At management thresholds of

  9. Multiple ionization of helium and krypton by electron impact close to threshold: appearance energies and Wannier exponents

    NASA Astrophysics Data System (ADS)

    Denifl, S.; Gstir, B.; Hanel, G.; Feketeova, L.; Matejcik, S.; Becker, K.; Stamatovic, A.; Scheier, P.; Märk, T. D.

    2002-11-01

    We determined appearance energy (AE) values AE(Xn+/X) for the formation of singly (He+) and doubly charged (He2+) He ions and multiply charged Kr ions Krn+ up to n = 6 following electron impact on He and Kr atoms using a high-resolution electron impact ionization mass spectrometer. The data analysis employs an iterative, non-linear least-squares fitting routine, the Marquart-Levenberg algorithm, in conjunction with either a 2-function or a 3-function fit based on a power threshold law. This allows us to extract the relevant AEs and also the corresponding exponents for a Wannier-type power law from the measured near-threshold data. The values of the AEs determined in this work are compared with other available experimental and with spectroscopic AE values and the extracted exponents p are compared with other available experimental data and with the predictions of the various Wannier-type power law models. One observation is particularly noteworthy, namely the fact that none of the available experimental data seem to support the large values of 'p' predicted by the Wannier-Geltman and the generalized Wannier law for n > 3.

  10. Electron impact multiple ionization of neon, argon and xenon atoms close to threshold: appearance energies and Wannier exponents

    NASA Astrophysics Data System (ADS)

    Gstir, B.; Denifl, S.; Hanel, G.; Rümmele, M.; Fiegele, T.; Cicman, P.; Stano, M.; Matejcik, S.; Scheier, P.; Becker, K.; Stamatovic, A.; Märk, T. D.

    2002-07-01

    We report the results of the experimental determination of the appearance energy values AE(Xn + /X) for the formation of multiply charged Ne, Ar and Xe ions up to n = 4 (Ne), n = 6 (Ar) and n = 8 (Xe) following electron impact on Ne, Ar and Xe atoms using a dedicated high-resolution electron impact ionization mass spectrometer. The data analysis uses the Marquart-Levenberg algorithm, which is an iterative, nonlinear least-squares-fitting routine, in conjunction with either a two-function or a three-function fit based on a power threshold law. This allows us to extract the relevant AEs and corresponding exponents for a Wannier-type power law from the measured near-threshold data. The values of the AEs determined in this work are compared with other available experimental and spectroscopic values of the AEs and the extracted exponents are compared with other available experimental data and with the predictions of the various Wannier-type power law models.

  11. Multiple imputation for multivariate data with missing and below-threshold measurements: time-series concentrations of pollutants in the Arctic.

    PubMed

    Hopke, P K; Liu, C; Rubin, D B

    2001-03-01

    Many chemical and environmental data sets are complicated by the existence of fully missing values or censored values known to lie below detection thresholds. For example, week-long samples of airborne particulate matter were obtained at Alert, NWT, Canada, between 1980 and 1991, where some of the concentrations of 24 particulate constituents were coarsened in the sense of being either fully missing or below detection limits. To facilitate scientific analysis, it is appealing to create complete data by filling in missing values so that standard complete-data methods can be applied. We briefly review commonly used strategies for handling missing values and focus on the multiple-imputation approach, which generally leads to valid inferences when faced with missing data. Three statistical models are developed for multiply imputing the missing values of airborne particulate matter. We expect that these models are useful for creating multiple imputations in a variety of incomplete multivariate time series data sets. PMID:11252602

  12. Thresholds of Knowledge Development in Complex Problem Solving: A Multiple-Case Study of Advanced Learners' Cognitive Processes

    ERIC Educational Resources Information Center

    Bogard, Treavor; Liu, Min; Chiang, Yueh-hui Vanessa

    2013-01-01

    This multiple-case study examined how advanced learners solved a complex problem, focusing on how their frequency and application of cognitive processes contributed to differences in performance outcomes, and developing a mental model of a problem. Fifteen graduate students with backgrounds related to the problem context participated in the study.…

  13. Adaptive Thresholds

    SciTech Connect

    Bremer, P. -T.

    2014-08-26

    ADAPT is a topological analysis code that allow to compute local threshold, in particular relevance based thresholds for features defined in scalar fields. The initial target application is vortex detection but the software is more generally applicable to all threshold based feature definitions.

  14. Formation of combined partially recessed and multiple fluorinated-dielectric layers gate structures for high threshold voltage GaN-based HEMT power devices

    NASA Astrophysics Data System (ADS)

    Huang, Huolin; Liang, Yung Chii

    2015-12-01

    The formation of partial AlGaN trench recess filled with multiple fluorinated gate dielectric layers as metal-insulator-semiconductor (MIS) gate structure for GaN-based HEMT power devices is designed, fabricated and experimentally verified. The approach realizes the device normally-off operational mode and at the same time is able to preserve the good mobility in the 2DEG channel for a maximum on-state current. Experimental measurements on the fabricated MIS-HEMT devices indicate a high gate threshold voltage (Vth) at around 5 V and a very low gate leakage current at pA/mm level. This proposed gate structure provides very promising properties for GaN-based power semiconductor devices in future power electronics switching applications.

  15. Arise the systems physician.

    PubMed

    Scott, I; Phelps, G; Dalton, S

    2014-12-01

    Healthcare in Australia faces significant challenges. Variations in care, suboptimal safety and reliability, fragmentation of care and unsustainable cost increases are compounded by substantial overuse and underuse of clinical interventions. These problems arise not from intentional actions of individual clinicians, but from deficiencies in the design, operations and governance of systems of care. Physicians play an important role in optimising systems of care and, in doing so, must rely on enhanced skills in a range of domains. These include: how to evaluate and improve quality and safety of clinical processes; analyse and interpret clinical and administrative data in ways that can be used to enhance care delivery; build and lead cohesive multidisciplinary teams capable of solving operational defects and inefficient workarounds; and implement new and effective innovations in clinical service delivery. While clinical skills are essential in individual patient care, skills that improve systems of care targeting whole patient populations will become increasingly desirable and recognised as core skills. PMID:25442761

  16. [Nonlinear magnetohydrodynamics]. [Threshold unstable MHD activity

    SciTech Connect

    Not Available

    1992-01-01

    Theoretical predictions were compared with available data from JET on the threshold unstable MHD activity in toroidal confinement devices. In particular, questions arising as to Hartmans number and the selection of a kinematic viscosity are discussed.

  17. Kapteyn series arising in radiation problems

    NASA Astrophysics Data System (ADS)

    Lerche, I.; Tautz, R. C.

    2008-01-01

    In discussing radiation from multiple point charges or magnetic dipoles, moving in circles or ellipses, a variety of Kapteyn series of the second kind arises. Some of the series have been known in closed form for a hundred years or more, others appear not to be available to analytic persuasion. This paper shows how 12 such generic series can be developed to produce either closed analytic expressions or integrals that are not analytically tractable. In addition, the method presented here may be of benefit when one has other Kapteyn series of the second kind to consider, thereby providing an additional reason to consider such series anew.

  18. Optimal thresholds for the estimation of area rain-rate moments by the threshold method

    NASA Technical Reports Server (NTRS)

    Short, David A.; Shimizu, Kunio; Kedem, Benjamin

    1993-01-01

    Optimization of the threshold method, achieved by determination of the threshold that maximizes the correlation between an area-average rain-rate moment and the area coverage of rain rates exceeding the threshold, is demonstrated empirically and theoretically. Empirical results for a sequence of GATE radar snapshots show optimal thresholds of 5 and 27 mm/h for the first and second moments, respectively. Theoretical optimization of the threshold method by the maximum-likelihood approach of Kedem and Pavlopoulos (1991) predicts optimal thresholds near 5 and 26 mm/h for lognormally distributed rain rates with GATE-like parameters. The agreement between theory and observations suggests that the optimal threshold can be understood as arising due to sampling variations, from snapshot to snapshot, of a parent rain-rate distribution. Optimal thresholds for gamma and inverse Gaussian distributions are also derived and compared.

  19. High resolution multiple electron impact ionisation of He, Ne, Ar, Kr and Xe atoms close to threshold: Appearance energies and Wannier exponents

    NASA Astrophysics Data System (ADS)

    Gstir, B.; Denifl, S.; Hanel, G.; Rümmele, M.; Fiegele, T.; Stano, M.; Feketeova, L.; Matejcik, S.; Becker, K.; Scheier, P.; Märk, T. D.

    2003-05-01

    We have determined appearance energies AE(X n+ /X) for the formation of multiply charged He, Ne, Ar, Kr and Xe ions up to charge state n=2 (He), n=4 (Ne), n=6 (Ar), n=6 (Kr) and n=8 (Xe) using a recently commissioned high-resolution electron impact ionization mass spectrometer. The data analysis is based on the Marquart-Levenberg algorithm, involving an iterative, non-linear least-squares fitting of the threshold data assuming a 2-function or a 3-function fit based on a Wannier-type power law. This allows us to extract the relevant AEs and corresponding Wannier exponents.

  20. Schwannoma arising from intramasseteric region.

    PubMed

    He, Yue; Fu, Hong Hai; He, Jie; Zhu, Han Guang; Zhang, Zhi Yuan

    2010-11-01

    Schwannoma in the head and neck is usually arising in the parapharyngeal space, but intramasseteric schwannoma is very rare. We report a schwannoma arising from masseter muscle in a middle-aged woman, who presented with a history of a painless right cheek mass for 3 years. Computed tomography scan suggested that the mass was located within the masseter muscle. Fine-needle aspiration was performed and showed spindle neoplastic cells, which were suspected to be of mesenchymal tissue origin. The mass was completely resected under general anesthesia. It was a well-circumscribed and lobulated mass, 4 × 3 × 2 cm in size. Histological examination gave the diagnosis of schwannoma, which was also confirmed by immunohistochemical stainings for S-100 and vimentin. Neurologic sequelae and recurrence were not found at 2 years after surgery. PMID:21119484

  1. Threshold selection for regional peaks-over-threshold data

    NASA Astrophysics Data System (ADS)

    Roth, Martin; Jongbloed, Geurt; Adri Buishand, T.

    2016-04-01

    A hurdle in the peaks-over-threshold approach for analyzing extreme values is the selection of the threshold. A method is developed to reduce this obstacle in the presence of multiple, similar data samples. This is for instance the case in many environmental applications. The idea is to combine threshold selection methods into a regional method. Regionalized versions of the threshold stability and the mean excess plot are presented as graphical tools for threshold selection. Moreover, quantitative approaches based on the bootstrap distribution of the spatially averaged Kolmogorov-Smirnov and Anderson-Darling test statistics are introduced. It is demonstrated that the proposed regional method leads to an increased sensitivity for too low thresholds, compared to methods that do not take into account the regional information. The approach can be used for a wide range of univariate threshold selection methods. We test the methods using simulated data and present an application to rainfall data from the Dutch water board Vallei en Veluwe.

  2. Overcoming the effects of false positives and threshold bias in graph theoretical analyses of neuroimaging data

    PubMed Central

    Drakesmith, M.; Caeyenberghs, K.; Dutt, A.; Lewis, G.; David, A.S.; Jones, D.K.

    2015-01-01

    Graph theory (GT) is a powerful framework for quantifying topological features of neuroimaging-derived functional and structural networks. However, false positive (FP) connections arise frequently and influence the inferred topology of networks. Thresholding is often used to overcome this problem, but an appropriate threshold often relies on a priori assumptions, which will alter inferred network topologies. Four common network metrics (global efficiency, mean clustering coefficient, mean betweenness and smallworldness) were tested using a model tractography dataset. It was found that all four network metrics were significantly affected even by just one FP. Results also show that thresholding effectively dampens the impact of FPs, but at the expense of adding significant bias to network metrics. In a larger number (n = 248) of tractography datasets, statistics were computed across random group permutations for a range of thresholds, revealing that statistics for network metrics varied significantly more than for non-network metrics (i.e., number of streamlines and number of edges). Varying degrees of network atrophy were introduced artificially to half the datasets, to test sensitivity to genuine group differences. For some network metrics, this atrophy was detected as significant (p < 0.05, determined using permutation testing) only across a limited range of thresholds. We propose a multi-threshold permutation correction (MTPC) method, based on the cluster-enhanced permutation correction approach, to identify sustained significant effects across clusters of thresholds. This approach minimises requirements to determine a single threshold a priori. We demonstrate improved sensitivity of MTPC-corrected metrics to genuine group effects compared to an existing approach and demonstrate the use of MTPC on a previously published network analysis of tractography data derived from a clinical population. In conclusion, we show that there are large biases and instability

  3. Melanoma arising after imiquimod use.

    PubMed

    Paul, Sharad P

    2014-01-01

    Imiquimod belongs to the class of 1H-imidazo-[4,5-c]quinolones-drugs originally developed as nucleoside analogues with the aim of finding new potential antiviral agents (Harrison et al., 1988). Indeed, Imiquimod was first released as treatment for genital warts before its actions against skin cancer were studied. Imiquimod is a relatively small sized molecule (Mr = 240.3) and is hydrophobic, allowing it to penetrate the skin epidermal barrier and therefore making it suitable for topical formulations (Gerster et al., 2005). Imiquimod has shown itself effective against skin cancers and precancerous lesions, especially basal cell cancers and actinic keratosis (Salasche et al., 2002, Beutner et al., 1999). There have been reports of Imiquimod being used as topical treatment against cutaneous metastases of melanoma and some authors have reported its use as first-line therapy against melanoma in situ (Smyth et al., 2011, Gagnon, 2011). We report a case of an invasive malignant melanoma arising de novo at the specific site of application of Imiquimod (Aldara cream 5%) for a biopsy-proven superficial BCC. Therefore while Imiquimod has added to our topical armamentarium against skin cancer, care must be exercised in prescribing this treatment and it is especially important to follow up patients regularly. PMID:25431597

  4. Neurocytoma arising in the pelvis.

    PubMed

    Friedrichs, Nicolaus; Vorreuther, Roland; Fischer, Hans-Peter; Wiestler, Otmar D; Buettner, Reinhard

    2003-08-01

    Central neurocytoma represents a rare neoplasm of the central nervous system with advanced neurocytic and sometimes focal lipomatous differentiation, a low proliferative potential and a favorable prognosis depending on the efficiency of surgical resection. This entity has been described as an intraventricular tumor near the foramen Monroi. Here, we report a case of a 21-year-old male with peripheral neurocytoma. Using computed tomography, a tumor of unknown origin was located behind the bladder. After complete surgical resection of the tumor, histologically small uniform cells, zones of fibrillarity and neuropil-like islands were seen. Immunohistochemistry revealed positivity for the neuronal markers synaptophysin, neuron-specific enolase and neurofilaments. Vimentin, pan-keratin, desmin, chromogranin, CD-99 and glial fibrillary acidic protein were immuno-negative. A low proliferation rate (1-2%) was found. Several case reports described extraventricular central neurocytomas. A sole publication documented a peripheral neurocytoma arising within a mature cystic teratoma of the ovary. To our knowledge, this is the second reported case of a neurocytoma outside the central nervous system, indicating that this entity may also occur infrequently in peripheral tissues. PMID:12844263

  5. CARA Risk Assessment Thresholds

    NASA Technical Reports Server (NTRS)

    Hejduk, M. D.

    2016-01-01

    Warning remediation threshold (Red threshold): Pc level at which warnings are issued, and active remediation considered and usually executed. Analysis threshold (Green to Yellow threshold): Pc level at which analysis of event is indicated, including seeking additional information if warranted. Post-remediation threshold: Pc level to which remediation maneuvers are sized in order to achieve event remediation and obviate any need for immediate follow-up maneuvers. Maneuver screening threshold: Pc compliance level for routine maneuver screenings (more demanding than regular Red threshold due to additional maneuver uncertainty).

  6. Four Different Tumors Arising in a Nevus Sebaceous.

    PubMed

    Namiki, Takeshi; Miura, Keiko; Ueno, Makiko; Arima, Yumi; Nishizawa, Aya; Yokozeki, Hiroo

    2016-01-01

    Nevus sebaceous is known by its association with one or more secondary tumors, but more than three multiple tumors arising from a nevus sebaceous is extremely rare. A 67-year-old female presented with a light brown plaque on the back of her head that contained a dome-shaped black node and an erosive lesion. Histopathological examination showed atypical basaloid cells in the black node. At the periphery of that node, structures resembling follicular germs extruded from interlacing cords in the upper portion and tumor nests with sebocytes were in the lower portion. In the erosive lesion, papillated structures with an apocrine epithelium were observed. In the light brown plaque, enlargement of sebaceous lobules was noted. From those histopathological features, a diagnosis of syringocystadenoma papilliferum, sebaceoma, trichoblastoma and basal cell carcinoma arising from a nevus sebaceous was made. We discuss the rarity of multiple tumors arising from a nevus sebaceous. PMID:27194974

  7. Four Different Tumors Arising in a Nevus Sebaceous

    PubMed Central

    Namiki, Takeshi; Miura, Keiko; Ueno, Makiko; Arima, Yumi; Nishizawa, Aya; Yokozeki, Hiroo

    2016-01-01

    Nevus sebaceous is known by its association with one or more secondary tumors, but more than three multiple tumors arising from a nevus sebaceous is extremely rare. A 67-year-old female presented with a light brown plaque on the back of her head that contained a dome-shaped black node and an erosive lesion. Histopathological examination showed atypical basaloid cells in the black node. At the periphery of that node, structures resembling follicular germs extruded from interlacing cords in the upper portion and tumor nests with sebocytes were in the lower portion. In the erosive lesion, papillated structures with an apocrine epithelium were observed. In the light brown plaque, enlargement of sebaceous lobules was noted. From those histopathological features, a diagnosis of syringocystadenoma papilliferum, sebaceoma, trichoblastoma and basal cell carcinoma arising from a nevus sebaceous was made. We discuss the rarity of multiple tumors arising from a nevus sebaceous. PMID:27194974

  8. Optimal control of multiplicative control systems arising from cancer therapy

    NASA Technical Reports Server (NTRS)

    Bahrami, K.; Kim, M.

    1975-01-01

    This study deals with ways of curtailing the rapid growth of cancer cell populations. The performance functional that measures the size of the population at the terminal time as well as the control effort is devised. With use of the discrete maximum principle, the Hamiltonian for this problem is determined and the condition for optimal solutions are developed. The optimal strategy is shown to be a bang-bang control. It is shown that the optimal control for this problem must be on the vertices of an N-dimensional cube contained in the N-dimensional Euclidean space. An algorithm for obtaining a local minimum of the performance function in an orderly fashion is developed. Application of the algorithm to the design of antitumor drug and X-irradiation schedule is discussed.

  9. Threshold quantum cryptography

    SciTech Connect

    Tokunaga, Yuuki; Okamoto, Tatsuaki; Imoto, Nobuyuki

    2005-01-01

    We present the concept of threshold collaborative unitary transformation or threshold quantum cryptography, which is a kind of quantum version of threshold cryptography. Threshold quantum cryptography states that classical shared secrets are distributed to several parties and a subset of them, whose number is greater than a threshold, collaborates to compute a quantum cryptographic function, while keeping each share secretly inside each party. The shared secrets are reusable if no cheating is detected. As a concrete example of this concept, we show a distributed protocol (with threshold) of conjugate coding.

  10. A threshold for dissipative fission

    SciTech Connect

    Thoennessen, M.; Bertsch, G.F.

    1993-09-21

    The empirical domain of validity of statistical theory is examined as applied to fission data on pre-fission data on pre-fission neutron, charged particle, and {gamma}-ray multiplicities. Systematics are found of the threshold excitation energy for the appearance of nonstatistical fission. From the data on systems with not too high fissility, the relevant phenomenological parameter is the ratio of the threshold temperature T{sub thresh} to the (temperature-dependent) fission barrier height E{sub Bar}(T). The statistical model reproduces the data for T{sub thresh}/E{sub Bar}(T) < 0.26 {plus_minus} 0.05, but underpredicts the multiplicities at higher T{sub thresh}/E{sub Bar}(T) independent of mass and fissility of the systems.

  11. Threshold Concepts in Biochemistry

    ERIC Educational Resources Information Center

    Loertscher, Jennifer

    2011-01-01

    Threshold concepts can be identified for any discipline and provide a framework for linking student learning to curricular design. Threshold concepts represent a transformed understanding of a discipline, without which the learner cannot progress and are therefore pivotal in learning in a discipline. Although threshold concepts have been…

  12. Epidemic thresholds for bipartite networks

    NASA Astrophysics Data System (ADS)

    Hernández, D. G.; Risau-Gusman, S.

    2013-11-01

    It is well known that sexually transmitted diseases (STD) spread across a network of human sexual contacts. This network is most often bipartite, as most STD are transmitted between men and women. Even though network models in epidemiology have quite a long history now, there are few general results about bipartite networks. One of them is the simple dependence, predicted using the mean field approximation, between the epidemic threshold and the average and variance of the degree distribution of the network. Here we show that going beyond this approximation can lead to qualitatively different results that are supported by numerical simulations. One of the new features, that can be relevant for applications, is the existence of a critical value for the infectivity of each population, below which no epidemics can arise, regardless of the value of the infectivity of the other population.

  13. Pausing at the Threshold

    ERIC Educational Resources Information Center

    Morgan, Patrick K.

    2015-01-01

    Since about 2003, the notion of threshold concepts--the central ideas in any field that change how learners think about other ideas--have become difficult to escape at library conferences and in general information literacy discourse. Their visibility will likely only increase because threshold concepts figure prominently in the Framework for…

  14. Threshold Concepts in Economics

    ERIC Educational Resources Information Center

    Shanahan, Martin

    2016-01-01

    Purpose: The purpose of this paper is to examine threshold concepts in the context of teaching and learning first-year university economics. It outlines some of the arguments for using threshold concepts and provides examples using opportunity cost as an exemplar in economics. Design/ Methodology/Approach: The paper provides an overview of the…

  15. Bayesian Threshold Estimation

    ERIC Educational Resources Information Center

    Gustafson, S. C.; Costello, C. S.; Like, E. C.; Pierce, S. J.; Shenoy, K. N.

    2009-01-01

    Bayesian estimation of a threshold time (hereafter simply threshold) for the receipt of impulse signals is accomplished given the following: 1) data, consisting of the number of impulses received in a time interval from zero to one and the time of the largest time impulse; 2) a model, consisting of a uniform probability density of impulse time…

  16. Cesium vapor thermionic converter anomalies arising from negative ion emission

    NASA Astrophysics Data System (ADS)

    Rasor, Ned S.

    2016-08-01

    Compelling experimental evidence is given that a longstanding limit encountered on cesium vapor thermionic energy converter performance improvement and other anomalies arise from thermionic emission of cesium negative ions. It is shown that the energy that characterizes thermionic emission of cesium negative ions is 1.38 eV and, understandably, is not the electron affinity 0.47 eV determined for the photodetachment threshold of the cesium negative ion. The experimental evidence includes measurements of collector work functions and volt-ampere characteristics in quasi-vacuum cesium vapor thermionic diodes, along with reinterpretation of the classic Taylor-Langmuir S-curve data on electron emission in cesium vapor. The quantitative effects of negative ion emission on performance in the ignited, unignited, and quasi-vacuum modes of cesium vapor thermionic converter operation are estimated.

  17. Linking Pattern Formation and Alternative Stable States: Ecohydrologic Thresholds and Critical Transitions in the Everglades Peatlands

    NASA Astrophysics Data System (ADS)

    Heffernan, J. B.; Ross, M. S.; Sah, J. P.; Isherwood, E.; Cohen, M. J.

    2015-12-01

    Spatial patterning occurs in a variety of ecosystems, and is important for the functional properties of landscapes; for testing spatial models of ecological processes; and as an indicator of landscape condition and resilience. Theory suggests that regular patterns arise from coupled local- and landscape-scale feedbacks that can also create multiple stable landscape states. In the Florida Everglades, hydrologic modification has degraded much of the historically-extensive ridge-slough landscape, a patterned peatland mosaic with distinct, flow-parallel patches. However, in the Everglades and in general, the hypothesis that patterned landscapes have homogeneous alternative states has little direct empirical support. Here we use microtopographic and vegetative heterogeneity, and their relation to hydrologic conditions, to infer the existence of multiple landscape equilibria and identify the hydrologic thresholds for critical transitions between these states. Dual relationships between elevation variance and water depth, and bi-modal distributions of both elevation variance and plant community distinctness, are consistent with generic predictions of multiple states, and covariation between these measures suggests that microtopography is the leading indicator of landscape degradation. Furthermore, a simple ecohydrologic multiple-state model correctly predicts the hydrologic thresholds for persistence of distinct ridges and sloughs. Predicted ridge-slough elevation differences and their relation to water depth are much greater than observed in the contemporary Everglades, but correspond closely with historical observations of pre-drainage conditions. These multiple lines of evidence represent the broadest and most direct support for the link between regular spatial pattern and landscape-scale alternative states in any ecosystem, and suggest that other patterned landscapes could undergo sudden collapse in response to changing environmental conditions. Hydrologic thresholds

  18. Motion parallax thresholds for unambiguous depth perception.

    PubMed

    Holmin, Jessica; Nawrot, Mark

    2015-10-01

    The perception of unambiguous depth from motion parallax arises from the neural integration of retinal image motion and extra-retinal eye movement signals. It is only recently that these parameters have been articulated in the form of the motion/pursuit ratio. In the current study, we explored the lower limits of the parameter space in which observers could accurately perform near/far relative depth-sign discriminations for a translating random-dot stimulus. Stationary observers pursued a translating random dot stimulus containing relative image motion. Their task was to indicate the location of the peak in an approximate square-wave stimulus. We measured thresholds for depth from motion parallax, quantified as motion/pursuit ratios, as well as lower motion thresholds and pursuit accuracy. Depth thresholds were relatively stable at pursuit velocities 5-20 deg/s, and increased at lower and higher velocities. The pattern of results indicates that minimum motion/pursuit ratios are limited by motion and pursuit signals, both independently and in combination with each other. At low and high pursuit velocities, depth thresholds were limited by inaccurate pursuit signals. At moderate pursuit velocities, depth thresholds were limited by motion signals. PMID:26232612

  19. Clear cell adenocarcinoma arising from adenomyosis.

    PubMed

    Hirabayashi, Kenichi; Yasuda, Masanori; Kajiwara, Hiroshi; Nakamura, Naoya; Sato, Shigeru; Nishijima, Yoshihiro; Mikami, Mikio; Osamura, Robert Yoshiyuki

    2009-05-01

    A 73-year-old postmenopausal Japanese woman presented with a complaint of slight fever and weight loss. An elevated level of CA125 in the blood favored a diagnosis of malignant uterine body tumor, but was not confirmed by endometrial cytology and biopsy. Resection of the uterus revealed a solid whitish tumor in the myometrium that was diagnosed as clear cell adenocarcinoma (CCA) arising from adenomyosis. There were transitions between endometrial epithelium of adenomyosis, noninvasive CCA, and invasive CCA. Immunohistochemical expression of hepatocyte nuclear factor-1beta supported the diagnosis of CCA. Only one other English language document pertaining to CCA arising from adenomyosis exists. Malignant tumor arising from adenomyosis should be considered as a differential diagnosis when the serum level of tumor markers such as CA125 is high and when the tumor is intramyometrial. PMID:19620944

  20. Endometrial carcinoma arising in a bicornuate uterus

    PubMed Central

    Munkhdelger, Jijgee; Mia-Jan, Khalilullah; Cha, Dong Soo

    2014-01-01

    Endometrial carcinomas arising in a bicornuate uterus are rare, only five case of which have been previously reported. We present a case of endometrial cancer arising in a bicornuate uterus, occurring in a 65-year-old woman. Unlike previously reported cases, our case showed mixed endometrial adenocarcinoma and undifferentiated carcinoma in one horn and focal adenocarcinoma in the other. Adequate tissue sampling of both horns is necessary for accurate diagnosis of malignancy in patients with a bicornuate uterus. Physicians should be aware of the possibility of this abnormality in cases when endometrial cancer is suspected but histology fails to confirm. PMID:25264532

  1. Hydrodynamics of sediment threshold

    NASA Astrophysics Data System (ADS)

    Ali, Sk Zeeshan; Dey, Subhasish

    2016-07-01

    A novel hydrodynamic model for the threshold of cohesionless sediment particle motion under a steady unidirectional streamflow is presented. The hydrodynamic forces (drag and lift) acting on a solitary sediment particle resting over a closely packed bed formed by the identical sediment particles are the primary motivating forces. The drag force comprises of the form drag and form induced drag. The lift force includes the Saffman lift, Magnus lift, centrifugal lift, and turbulent lift. The points of action of the force system are appropriately obtained, for the first time, from the basics of micro-mechanics. The sediment threshold is envisioned as the rolling mode, which is the plausible mode to initiate a particle motion on the bed. The moment balance of the force system on the solitary particle about the pivoting point of rolling yields the governing equation. The conditions of sediment threshold under the hydraulically smooth, transitional, and rough flow regimes are examined. The effects of velocity fluctuations are addressed by applying the statistical theory of turbulence. This study shows that for a hindrance coefficient of 0.3, the threshold curve (threshold Shields parameter versus shear Reynolds number) has an excellent agreement with the experimental data of uniform sediments. However, most of the experimental data are bounded by the upper and lower limiting threshold curves, corresponding to the hindrance coefficients of 0.2 and 0.4, respectively. The threshold curve of this study is compared with those of previous researchers. The present model also agrees satisfactorily with the experimental data of nonuniform sediments.

  2. ARISE: American renaissance in science education

    SciTech Connect

    1998-09-14

    The national standards and state derivatives must be reinforced by models of curricular reform. In this paper, ARISE presents one model based on a set of principles--coherence, integration of the sciences, movement from concrete ideas to abstract ones, inquiry, connection and application, sequencing that is responsive to how people learn.

  3. Mitochondrial threshold effects.

    PubMed Central

    Rossignol, Rodrigue; Faustin, Benjamin; Rocher, Christophe; Malgat, Monique; Mazat, Jean-Pierre; Letellier, Thierry

    2003-01-01

    The study of mitochondrial diseases has revealed dramatic variability in the phenotypic presentation of mitochondrial genetic defects. To attempt to understand this variability, different authors have studied energy metabolism in transmitochondrial cell lines carrying different proportions of various pathogenic mutations in their mitochondrial DNA. The same kinds of experiments have been performed on isolated mitochondria and on tissue biopsies taken from patients with mitochondrial diseases. The results have shown that, in most cases, phenotypic manifestation of the genetic defect occurs only when a threshold level is exceeded, and this phenomenon has been named the 'phenotypic threshold effect'. Subsequently, several authors showed that it was possible to inhibit considerably the activity of a respiratory chain complex, up to a critical value, without affecting the rate of mitochondrial respiration or ATP synthesis. This phenomenon was called the 'biochemical threshold effect'. More recently, quantitative analysis of the effects of various mutations in mitochondrial DNA on the rate of mitochondrial protein synthesis has revealed the existence of a 'translational threshold effect'. In this review these different mitochondrial threshold effects are discussed, along with their molecular bases and the roles that they play in the presentation of mitochondrial diseases. PMID:12467494

  4. New challenges of the ARISE project

    NASA Astrophysics Data System (ADS)

    Blanc, Elisabeth

    2015-04-01

    It has been robustly demonstrated that variations in the circulation of the middle atmosphere influence weather and climate throughout the troposphere all the way to the Earth's surface. A key part of the coupling between the troposphere and stratosphere occurs through the propagation and breaking of planetary-scale Rossby waves and gravity waves. Limited observation of the middle atmosphere and these waves in particular limits the ability to faithfully reproduce the dynamics of the middle atmosphere in numerical weather prediction and climate models. The ARISE project combines for the first time international networks with complementary technologies such as infrasound, lidar and airglow. This joint network provided advanced data products that started to be used as benchmarks for weather forecast models. The ARISE network also allows enhanced and detailed monitoring of other extreme events in the Earth system such as erupting volcanoes, magnetic storms, tornadoes and tropical thunderstorms. In order to improve the ability of the network to monitor atmospheric dynamics, ARISE proposes to extend i) the existing network coverage in Africa and the high latitudes, ii) the altitude range in the stratosphere and mesosphere, iii) the observation duration using routine observation modes, and to use complementary existing infrastructures and innovative instrumentations. Data will be collected over the long term to improve weather forecasting to monthly or seasonal timescales, to monitor atmospheric extreme events and climate change. ARISE focuses on the link between models and observations for future assimilation of data by operational weather forecasting models. Among the applications, ARISE2 proposes infrasound remote volcano monitoring to provide notifications to civil aviation.

  5. Prolonged Training at Threshold Promotes Robust Retinotopic Specificity in Perceptual Learning

    PubMed Central

    Hung, Shao-Chin

    2014-01-01

    Human perceptual learning is classically thought to be highly specific to trained stimuli's retinal location. Together with evidence that specific learning effects can result in corresponding changes in early visual cortex, researchers have theorized that specificity implies regionalization of learning in the brain. However, other research suggests that specificity can arise from learning readout in decision areas or through top-down processes. Notably, recent research using a novel double-training paradigm reveals dramatic generalization of perceptual learning to untrained locations when multiple stimuli are trained. These data provoked significant controversy in the field and challenged extant models of perceptual learning. To resolve this controversy, we investigated mechanisms that account for retinotopic specificity in perceptual learning. We replicated findings of transfer after double training; however, we show that prolonged training at threshold, which leads to a greater number of difficult trials during training, preserves location specificity when double training occurred at the same location or sequentially at different locations. Likewise, we find that prolonged training at threshold determines the degree of transfer in single training of a peripheral orientation discrimination task. Together, these data show that retinotopic specificity depends highly upon particularities of the training procedure. We suggest that perceptual learning can arise from decision rules, attention learning, or representational changes, and small differences in the training approach can emphasize some of these over the others. PMID:24948798

  6. Yield threshold decision framework

    SciTech Connect

    Judd, B.R.; Younker, L.W.; Hannon, W.J.

    1989-08-17

    The USA is developing a decision analysis framework for evaluating the relative value of lower yield thresholds and related verification policies. The framework facilitates systematic analysis of the major issues in the yield threshold decision. The framework can be used to evaluate options proposed either in the inter-agency process or in the negotiations. In addition, the framework can measure the importance of uncertainties and alternative judgments, and thereby determine the advantages of additional research. Since the model is explicit and quantitative, it provides a rational, defensible approach for reaching important treaty and verification decisions. 9 figs.

  7. Ameloblastic Fibrosarcoma Arising in the Maxilla

    PubMed Central

    Pillay, Rachael R.; Bilski, Arthur; Batstone, Martin

    2016-01-01

    Background: Ameloblastic fibrosarcoma (AFS) is a rare odontogenic neoplasm of the jaw that usually arises de novo or through a malignant change in the mesenchymal component of a preexisting or recurrent benign fibroma. The majority of AFS cases reported in the literature arise in the mandible. Case Report: A 35-year-old male presented with an asymptomatic left maxillary mass that on imaging was found to be effacing most of his maxillary sinus. He underwent a left maxillectomy with free-flap reconstruction and adjuvant radiotherapy to the tumor bed. Conclusion: Wide local excision remains the treatment of choice for AFS, given the poor survival rates of patients with recurrent disease. However, long-term studies and follow-up are needed to elucidate the role of adjuvant therapies in the primary treatment of AFS. PMID:27303223

  8. Elaborating on Threshold Concepts

    ERIC Educational Resources Information Center

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-01-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account…

  9. Anomalous threshold laws in quantum sticking.

    PubMed

    Clougherty, Dennis P

    2003-11-28

    It has been stated that for a short-ranged surface interaction, the probability of a low-energy particle sticking to a surface always vanishes as s approximately k with k-->0 where k=sqrt[E]. Deviations from this so-called universal threshold law are derived using a linear model of particle-surface scattering. The Fredholm theory of integral equations is used to find the global conditions necessary for a convergent solution. The exceptional case of a zero-energy resonance is considered in detail. Anomalous threshold laws, where s approximately k(1+alpha),alpha>0 as k-->0, are shown to arise from a soft gap in the weighted density of states of excitations; alpha is determined by the behavior of the weighted density of states near the binding energy. PMID:14683254

  10. Anomalous Threshold Laws in Quantum Sticking

    NASA Astrophysics Data System (ADS)

    Clougherty, Dennis P.

    2003-11-01

    It has been stated that for a short-ranged surface interaction, the probability of a low-energy particle sticking to a surface always vanishes as s˜k with k→0 where k=√(E). Deviations from this so-called universal threshold law are derived using a linear model of particle-surface scattering. The Fredholm theory of integral equations is used to find the global conditions necessary for a convergent solution. The exceptional case of a zero-energy resonance is considered in detail. Anomalous threshold laws, where s˜k1+α,α>0 as k→0, are shown to arise from a soft gap in the weighted density of states of excitations; α is determined by the behavior of the weighted density of states near the binding energy.

  11. Anomalous Threshold Laws in Quantum Sticking

    NASA Astrophysics Data System (ADS)

    Clougherty, Dennis

    2004-03-01

    It has been stated that for a short-ranged surface interaction, the probability of a low-energy particle sticking to a surface always vanishes as s ˜ k with k→ 0 where k=√E. Deviations from this so-called universal threshold law are derived using a linear model of particle-surface scattering. The Fredholm theory of integral equations is used to find the global conditions necessary for a convergent solution. The exceptional case of a zero-energy resonance is considered in detail. Anomalous threshold laws, where s ˜ k^1+α, α > 0 as k→ 0, are shown to arise from a soft gap in the weighted density of states of excitations; α is determined by the behavior of the weighted density of states near the binding energy.

  12. Physiological variability arising from in vitro propagation of Nothofagus obliqua.

    PubMed

    Martínez Pastur, G; Arena, M; Caso, O

    1998-12-01

    As with cuttings, the microcuttings produced from in vitro generated shoots could be affected by topophysis. Very little research has been done about such in vitro effect. This paper reports the influence of the topophysis on the regeneration response (shoot multiplication, microcutting rooting and plantlet acclimation) of explants on the in vitro culture of juvenile N. obliqua trees. The results showed that the main responsible of the physiological variability arising from all the in vitro propagation stages is topophysis. This influence was found in the first culture and can be extended to the next subculture (multiplication stage). Growth of the obtained plants was also affected (rooting of microcuttings and plantlet acclimation). The multiplication rate was lower in apical portion (1:3.66) than basal portion (1:5.8) while rooting was 48.6% and 27.0% respectively. By the way, length of acclimated explants was 52.4 mm in the apical rooted explants and 28.7 mm in the basal ones at the 30th day. In order to reduce such variability, it is necessary to take into account the initial position of the explants during the establishment and multiplication stages of micropropagation of forest trees. PMID:10892444

  13. Boundary estimation problems arising in thermal tomography

    NASA Technical Reports Server (NTRS)

    Banks, H. T.; Kojima, Fumio; Winfree, W. P.

    1989-01-01

    Problems on the identification of two-dimensional spatial domains arising in the detection and characterization of structural flaws in materials are considered. For a thermal diffusion system with external boundary input, observations of the temperature on the surface are used in a output least squares approach. Parameter estimation techniques based on the method of mappings are discussed and approximation schemes are developed based on a finite element Galerkin approach. Theoretical convergence results for computational techniques are given and the results are applied to experimental data for the identification of flaws in the thermal testing of materials.

  14. Eccrine Poroma Arising within Nevus Sebaceous

    PubMed Central

    Girdwichai, Natnicha; Chanprapaph, Kumutnart; Vachiramon, Vasanop

    2016-01-01

    Nevus sebaceous is a congenital, benign hamartomatous lesion, characterized by a yellowish to skin-colored, hairless, verrucous plaque on the head and neck region. In later life, a secondary tumor, either benign or malignant, can develop within nevus sebaceous. Eccrine poroma developing on nevus sebaceous is extremely rare. There are few case reports of eccrine poroma developing within nevus sebaceous. We report a case of a 30-year-old female who presented with a congenital, hairless, verrucous, yellowish lesion on the scalp and an erythematous nodule arising within the yellowish lesion for 8 months. Her clinical presentation and histopathological findings were compatible with nevus sebaceous and eccrine poroma. PMID:27194975

  15. Network problem threshold

    NASA Technical Reports Server (NTRS)

    Gejji, Raghvendra, R.

    1992-01-01

    Network transmission errors such as collisions, CRC errors, misalignment, etc. are statistical in nature. Although errors can vary randomly, a high level of errors does indicate specific network problems, e.g. equipment failure. In this project, we have studied the random nature of collisions theoretically as well as by gathering statistics, and established a numerical threshold above which a network problem is indicated with high probability.

  16. Elaborating on threshold concepts

    NASA Astrophysics Data System (ADS)

    Rountree, Janet; Robins, Anthony; Rountree, Nathan

    2013-09-01

    We propose an expanded definition of Threshold Concepts (TCs) that requires the successful acquisition and internalisation not only of knowledge, but also its practical elaboration in the domains of applied strategies and mental models. This richer definition allows us to clarify the relationship between TCs and Fundamental Ideas, and to account for both the important and the problematic characteristics of TCs in terms of the Knowledge/Strategies/Mental Models Framework defined in previous work.

  17. Threshold concepts in finance: conceptualizing the curriculum

    NASA Astrophysics Data System (ADS)

    Hoadley, Susan; Tickle, Leonie; Wood, Leigh N.; Kyng, Tim

    2015-08-01

    Graduates with well-developed capabilities in finance are invaluable to our society and in increasing demand. Universities face the challenge of designing finance programmes to develop these capabilities and the essential knowledge that underpins them. Our research responds to this challenge by identifying threshold concepts that are central to the mastery of finance and by exploring their potential for informing curriculum design and pedagogical practices to improve student outcomes. In this paper, we report the results of an online survey of finance academics at multiple institutions in Australia, Canada, New Zealand, South Africa and the United Kingdom. The outcomes of our research are recommendations for threshold concepts in finance endorsed by quantitative evidence, as well as a model of the finance curriculum incorporating finance, modelling and statistics threshold concepts. In addition, we draw conclusions about the application of threshold concept theory supported by both quantitative and qualitative evidence. Our methodology and findings have general relevance to the application of threshold concept theory as a means to investigate and inform curriculum design and delivery in higher education.

  18. An iterative curvelet thresholding algorithm for seismic random noise attenuation

    NASA Astrophysics Data System (ADS)

    Wang, De-Li; Tong, Zhong-Fei; Tang, Chen; Zhu, Heng

    2010-12-01

    In this paper, we explore the use of iterative curvelet thresholding for seismic random noise attenuation. A new method for combining the curvelet transform with iterative thresholding to suppress random noise is demonstrated and the issue is described as a linear inverse optimal problem using the L1 norm. Random noise suppression in seismic data is transformed into an L1 norm optimization problem based on the curvelet sparsity transform. Compared to the conventional methods such as median filter algorithm, FX deconvolution, and wavelet thresholding, the results of synthetic and field data processing show that the iterative curvelet thresholding proposed in this paper can sufficiently improve signal to noise radio (SNR) and give higher signal fidelity at the same time. Furthermore, to make better use of the curvelet transform such as multiple scales and multiple directions, we control the curvelet direction of the result after iterative curvelet thresholding to further improve the SNR.

  19. The intra-rater reliability and agreement of compensatory stepping thresholds of healthy subjects.

    PubMed

    Crenshaw, Jeremy R; Kaufman, Kenton R

    2014-02-01

    The purpose of this study was to evaluate the test-retest, intra-rater reliability and agreement of compensatory stepping thresholds. A protocol was developed to establish anteroposterior single-stepping thresholds, anteroposterior multiple-stepping thresholds, and lateral single-stepping thresholds. Healthy, young subjects stood on a microprocessor-controlled treadmill, and responded to three series of progressively challenging surface translations. Subjects were instructed to "try not to step" when establishing single-stepping thresholds or "try to take only one step" when establishing multiple-stepping thresholds. Stepping thresholds were defined as the minimum disturbance magnitude that consistently elicited a single or second compensatory step. Thresholds were expressed as the ankle torque necessary to maintain upright posture. Thresholds studied included anterior single-stepping thresholds (τ = 273.0 ± 82.3 N m), posterior single-stepping, thresholds (τ = 235.5 ± 98.0 N m), anterior multiple-stepping thresholds (τ = 977.0 ± 416.3 N m), posterior multiple-stepping thresholds (τ = 701.9 ± 237.5 N m), stability-side lateral single-stepping thresholds (τ = 225.7 ± 77.7 Nm), and mobility-side lateral single-stepping thresholds (τ = 236.8 ± 85.4 N m). Based on intraclass correlation coefficients (ICC) and Bland-Altman plots, all thresholds demonstrated excellent reliability (ICC(2,1) = 0.87-0.97) and agreement. These results suggest that compensatory stepping thresholds have sufficient repeatability to be used in clinical and research-related assessments of fall-risk. Additional study is needed to determine the intra- and inter-rater reliabilities and validity of thresholds specific to the patient populations of interest. PMID:24300837

  20. Coloring geographical threshold graphs

    SciTech Connect

    Bradonjic, Milan; Percus, Allon; Muller, Tobias

    2008-01-01

    We propose a coloring algorithm for sparse random graphs generated by the geographical threshold graph (GTG) model, a generalization of random geometric graphs (RGG). In a GTG, nodes are distributed in a Euclidean space, and edges are assigned according to a threshold function involving the distance between nodes as well as randomly chosen node weights. The motivation for analyzing this model is that many real networks (e.g., wireless networks, the Internet, etc.) need to be studied by using a 'richer' stochastic model (which in this case includes both a distance between nodes and weights on the nodes). Here, we analyze the GTG coloring algorithm together with the graph's clique number, showing formally that in spite of the differences in structure between GTG and RGG, the asymptotic behavior of the chromatic number is identical: {chi}1n 1n n / 1n n (1 + {omicron}(1)). Finally, we consider the leading corrections to this expression, again using the coloring algorithm and clique number to provide bounds on the chromatic number. We show that the gap between the lower and upper bound is within C 1n n / (1n 1n n){sup 2}, and specify the constant C.

  1. Laser threshold magnetometry

    NASA Astrophysics Data System (ADS)

    Jeske, Jan; Cole, Jared H.; Greentree, Andrew D.

    2016-01-01

    We propose a new type of sensor, which uses diamond containing the optically active nitrogen-vacancy (NV-) centres as a laser medium. The magnetometer can be operated at room-temperature and generates light that can be readily fibre coupled, thereby permitting use in industrial applications and remote sensing. By combining laser pumping with a radio-frequency Rabi-drive field, an external magnetic field changes the fluorescence of the NV- centres. We use this change in fluorescence level to push the laser above threshold, turning it on with an intensity controlled by the external magnetic field, which provides a coherent amplification of the readout signal with very high contrast. This mechanism is qualitatively different from conventional NV--based magnetometers which use fluorescence measurements, based on incoherent photon emission. We term our approach laser threshold magnetometer (LTM). We predict that an NV--based LTM with a volume of 1 mm3 can achieve shot-noise limited dc sensitivity of 1.86 fT /\\sqrt{{{Hz}}} and ac sensitivity of 3.97 fT /\\sqrt{{{Hz}}}.

  2. Chemodectomas arising in temporal bone structures

    SciTech Connect

    Dickens, W.J.; Million, R.R.; Cassisi, N.J.; Singleton, G.T.

    1982-02-01

    Eighteen patients with chemodectomas arising in temporal bone structures were evaluated and treated at the University of Florida. Seventeen patients have each been followed a minimum of 3 years. Patients were retrospectively staged as having ''local'' or ''advanced'' disease, depending on the presence or absence of bone destruction and/or cranial nerve involvement. Fourteen of the patients received radiation therapy as all or part of their therapy; 6 patients were treated with radiation therapy alone, 3 patients were irradiated immediately postoperatively for residual disease, and 5 patients had radiation therapy for recurrence after operation. They were treated with cobalt-60 radiation with doses ranging from 3760 to 5640 rad. All irradiated patients demonstrated evidence of tumor regression, and none have had tumor recurrence with followup of 3-12 years. Of the 8 patients with cranial nerve paralysis prior to therapy, 5 had return of function of 1 or more cranial nerves. One of 6 patients treated initially with radiation therapy had a complication, while 6 of 8 patients irradiated postoperatively had complications. None of the complications were fatal. Three patients treated by operation for early disease limited to the hypotympanum had the disease controlled for 11-12 years. Guidelines for the selection of initial therapy are discussed.

  3. [Chemical hazards arising from shale gas extraction].

    PubMed

    Pakulska, Daria

    2015-01-01

    The development of the shale industry is gaining momentum and hence the analysis of chemical hazards to the environment and health of the local population is extreiely timely and important. Chemical hazards are created during the exploitation of all minerals, but in the case of shale gas production, there is much more uncertainty as regards to the effects of new technologies application. American experience suggests the increasing risk of environmental contamination, mainly groundwater. The greatest, concern is the incomplete knowledge of the composition of fluids used for fracturing shale rock and unpredictability of long-term effects of hydraulic fracturing for the environment and health of residents. High population density in the old continent causes the problem of chemical hazards which is much larger than in the USA. Despite the growing public discontent data on this subject are limited. First of all, there is no epidemiological studies to assess the relationship between risk factors, such as air and water pollution, and health effects in populations living in close proximity to gas wells. The aim of this article is to identify and discuss existing concepts on the sources of environmental contamination, an indication of the environment elements under pressure and potential health risks arising from shale gas extraction. PMID:26016049

  4. Oscillatory Threshold Logic

    PubMed Central

    Borresen, Jon; Lynch, Stephen

    2012-01-01

    In the 1940s, the first generation of modern computers used vacuum tube oscillators as their principle components, however, with the development of the transistor, such oscillator based computers quickly became obsolete. As the demand for faster and lower power computers continues, transistors are themselves approaching their theoretical limit and emerging technologies must eventually supersede them. With the development of optical oscillators and Josephson junction technology, we are again presented with the possibility of using oscillators as the basic components of computers, and it is possible that the next generation of computers will be composed almost entirely of oscillatory devices. Here, we demonstrate how coupled threshold oscillators may be used to perform binary logic in a manner entirely consistent with modern computer architectures. We describe a variety of computational circuitry and demonstrate working oscillator models of both computation and memory. PMID:23173034

  5. Efficient threshold for volumetric segmentation

    NASA Astrophysics Data System (ADS)

    Burdescu, Dumitru D.; Brezovan, Marius; Stanescu, Liana; Stoica Spahiu, Cosmin; Ebanca, Daniel

    2015-07-01

    Image segmentation plays a crucial role in effective understanding of digital images. However, the research on the existence of general purpose segmentation algorithm that suits for variety of applications is still very much active. Among the many approaches in performing image segmentation, graph based approach is gaining popularity primarily due to its ability in reflecting global image properties. Volumetric image segmentation can simply result an image partition composed by relevant regions, but the most fundamental challenge in segmentation algorithm is to precisely define the volumetric extent of some object, which may be represented by the union of multiple regions. The aim in this paper is to present a new method to detect visual objects from color volumetric images and efficient threshold. We present a unified framework for volumetric image segmentation and contour extraction that uses a virtual tree-hexagonal structure defined on the set of the image voxels. The advantage of using a virtual tree-hexagonal network superposed over the initial image voxels is that it reduces the execution time and the memory space used, without losing the initial resolution of the image.

  6. ARISE - Advanced Radio Interferometry Between Space and Earth

    NASA Technical Reports Server (NTRS)

    Ulvestad, J. S.; Linfield, R. P.; Wannier, P. G.; Preston, R. A.; Hirabayashi, H.; Zensus, J. A.; Veal, G. R.

    1995-01-01

    A mission is described called ARISE, Advanced Radio Interferometry between Space and Earth. ARISE will will provide affordable very long baseline interferometry (VLBI) using second- generation VLBI and one or more inflatable space radio telescopes.

  7. Optimal selection of thresholds for photon counting CT

    NASA Astrophysics Data System (ADS)

    O'Donnell, Thomas; Schoeck, Friederike; Cheheltani, Rabee; Cormode, David; Fayad, Zahi A.

    2016-03-01

    Recent advances in Photon Counting CT (PCCT) have facilitated the simultaneous acquisition of multiple image volumes with differing energy thresholds. This presents the user with several choices for energy threshold combinations. As compared to standard clinical Dual kVp CT , where the user typically has only three choices of kVp pairings (e.g., 80/150Sn, 90/150Sn, 100/150Sn), a "quad" PCCT system with 14 threshold settings has Choose(14,4)= 1001 possible threshold combinations (assuming no restrictions). In this paper we describe a computationally tractable means to order, from best (most accurate) to worst (least accurate), threshold combinations for the task of discriminating pure materials of assumed approximate concentrations using the Bhattacharyya Coefficient. We observe that this ordering is not necessarily identical to the ordering for the task of decomposing material mixtures into their components. We demonstrate our approach on phantom data.

  8. Learning foraging thresholds for lizards

    SciTech Connect

    Goldberg, L.A.; Hart, W.E.; Wilson, D.B.

    1996-01-12

    This work gives a proof of convergence for a randomized learning algorithm that describes how anoles (lizards found in the Carribean) learn a foraging threshold distance. This model assumes that an anole will pursue a prey if and only if it is within this threshold of the anole`s perch. This learning algorithm was proposed by the biologist Roughgarden and his colleagues. They experimentally confirmed that this algorithm quickly converges to the foraging threshold that is predicted by optimal foraging theory our analysis provides an analytic confirmation that the learning algorithm converses to this optimal foraging threshold with high probability.

  9. Hairpin Vortex Regeneration Threshold

    NASA Astrophysics Data System (ADS)

    Sabatino, Daniel; Maharjan, Rijan

    2015-11-01

    A free surface water channel is used to study hairpin vortex formation created by fluid injection through a narrow slot into a laminar boundary layer. Particle image velocimetry is used to calculate the circulation of the primary hairpin vortex head which is found to monotonically decrease in strength with downstream distance. When a secondary hairpin vortex is formed upstream of the primary vortex, the circulation strength of the head is comparable to the strength of the primary head at the time of regeneration. However, the legs of the primary vortex strengthen up to the moment the secondary hairpin is generated. Although the peak circulation in the legs is not directly correlated to the strength of the original elongated ring vortex, when the circulation is scaled with the injection momentum ratio it is linearly related to scaled injection time. It is proposed that the injection momentum ratio and nondimensionalized injection time based on the wall normal penetration time can be used to identify threshold conditions which produce a secondary vortex. Supported by the National Science Foundation under Grant CBET- 1040236.

  10. Probabilistic Threshold Criterion

    SciTech Connect

    Gresshoff, M; Hrousis, C A

    2010-03-09

    The Probabilistic Shock Threshold Criterion (PSTC) Project at LLNL develops phenomenological criteria for estimating safety or performance margin on high explosive (HE) initiation in the shock initiation regime, creating tools for safety assessment and design of initiation systems and HE trains in general. Until recently, there has been little foundation for probabilistic assessment of HE initiation scenarios. This work attempts to use probabilistic information that is available from both historic and ongoing tests to develop a basis for such assessment. Current PSTC approaches start with the functional form of the James Initiation Criterion as a backbone, and generalize to include varying areas of initiation and provide a probabilistic response based on test data for 1.8 g/cc (Ultrafine) 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) and LX-17 (92.5% TATB, 7.5% Kel-F 800 binder). Application of the PSTC methodology is presented investigating the safety and performance of a flying plate detonator and the margin of an Ultrafine TATB booster initiating LX-17.

  11. Photodetachment Spectroscopy of La-: Resonances and Thresholds

    NASA Astrophysics Data System (ADS)

    Walter, C. W.; Gibson, N. D.; Crocker, C.; Dungan, K. A.; Matola, B. R.

    2015-05-01

    The negative ion of lanthanum, La-, has the richest bound state spectrum ever observed for an atomic negative ion, and it has been proposed as perhaps the best candidate for laser cooling of a negative ion. In the present experiments, photodetachment thresholds and transitions between bound states of La- are investigated using tunable infrared spectroscopy. The relative signal for neutral atom production was measured with a crossed ion-beam-laser-beam apparatus over the photon energy range 290-900 meV. The spectrum reveals at least 14 sharp resonance peaks due to transitions to either bound states of the negative ion or quasibound states in the continuum. Multiple photodetachment thresholds are also observed, providing information on the binding energies for some states of La-. This material is based on work supported by the National Science Foundation under Grant No. 1068308 and 1404109.

  12. Life below the threshold.

    PubMed

    Castro, C

    1991-01-01

    This article explains that malnutrition, poor health, and limited educational opportunities plague Philippine children -- especially female children -- from families living below the poverty threshold. Nearly 70% of households in the Philippines do not meet the required daily level of nutritional intake. Because it is often -- and incorrectly -- assumed that women's nutritional requirements are lower than men's, women suffer higher rates of malnutrition and poor health. A 1987 study revealed that 11.7% of all elementary students were underweight and 13.9% had stunted growths. Among elementary-school girls, 17% were malnourished and 40% suffered from anemia (among lactating mothers, more than 1/2 are anemic). A 1988 Program for Decentralized Educational Development study showed that grade VI students learn only about 1/2 of what they are supposed to learn. 30% of the children enrolled in grade school drop out before they reach their senior year. The Department of Education, Culture and Sports estimates that some 2.56 million students dropped out of school in l989. That same year, some 3.7 million children were counted as part of the labor force. In Manila alone, some 60,000 children work the streets, whether doing odd jobs or begging, or turning to crime or prostitution. the article tells the story of a 12 year-old girl named Ging, a 4th grader at a public school and the oldest child in a poor family of 6 children. The undernourished Ging dreams of a good future for her family and sees education as a way out of poverty; unfortunately, her time after school is spend working in the streets or looking after her family. She considers herself luckier than many of the other children working in the streets, since she at least has a family. PMID:12285009

  13. Threshold Hypothesis: Fact or Artifact?

    ERIC Educational Resources Information Center

    Karwowski, Maciej; Gralewski, Jacek

    2013-01-01

    The threshold hypothesis (TH) assumes the existence of complex relations between creative abilities and intelligence: linear associations below 120 points of IQ and weaker or lack of associations above the threshold. However, diverse results have been obtained over the last six decades--some confirmed the hypothesis and some rejected it. In this…

  14. The Nature of Psychological Thresholds

    ERIC Educational Resources Information Center

    Rouder, Jeffrey N.; Morey, Richard D.

    2009-01-01

    Following G. T. Fechner (1966), thresholds have been conceptualized as the amount of intensity needed to transition between mental states, such as between a states of unconsciousness and consciousness. With the advent of the theory of signal detection, however, discrete-state theory and the corresponding notion of threshold have been discounted.…

  15. Threshold Concepts and Information Literacy

    ERIC Educational Resources Information Center

    Townsend, Lori; Brunetti, Korey; Hofer, Amy R.

    2011-01-01

    What do we teach when we teach information literacy in higher education? This paper describes a pedagogical approach to information literacy that helps instructors focus content around transformative learning thresholds. The threshold concept framework holds promise for librarians because it grounds the instructor in the big ideas and underlying…

  16. Mars Dust Threshold Under Heated Surface Conditions

    NASA Astrophysics Data System (ADS)

    Coquilla, R. V.; White, B. R.

    2002-12-01

    A wind tunnel was used to study the effects of a heated surface, thereby creating an unstable near-surface atmosphere, on the threshold of aeolian-blown (windblown) dust-size particles (1-2 mm) under Mars-simulated pressure. Unstable conditions on Mars typically arise during the mid to late afternoon hours due to the accumulation of daytime solar-radiation. When the surface is warmer than the atmosphere just above it, vertical turbulence is increased. Thus, loose dust particles can be more easily lofted and mixed at a threshold wind speed lower than that known under neutral atmospheric conditions. For this wind-tunnel study, unstable (heated) surface conditions were simulated based on the negative temperature gradients and surface bulk Richardson numbers estimated from the Mars Pathfinder Lander (MPL) mission data during the mid-afternoon to early evening Mars period. According to other missions, evidence of highly active dust suspension during this part of the Mars daytime hours was recorded, including the presence of "dust devils". Experiments were performed in the Martian Surface Wind Tunnel (MARSWIT) located at NASA Ames Research Center, Moffett Field, California. Based on data acquired from the MPL site, the mean surface pressure was found to be 6.75 mb. Thus, simulations in MARSWIT were conducted at 10-mb atmospheric pressure using air, which agrees with a dynamically similar environment of 6.5 mb on Mars. In order to attain the necessary vertical temperature gradients that would develop an unstable layer, a test bed was heated by sub-surface heaters. Three surface roughness conditions were simulated, over which not only dust threshold was measured but also velocity and temperature profiles were acquired under various heating levels. Boundary layer measurements and analysis conducted under neutral conditions were used to estimate roughness height, zo, and the friction speed, u*, for all stability conditions. Dust threshold tests were conducted using a

  17. Learning regulatory programs by threshold SVD regression

    PubMed Central

    Ma, Xin; Xiao, Luo; Wong, Wing Hung

    2014-01-01

    We formulate a statistical model for the regulation of global gene expression by multiple regulatory programs and propose a thresholding singular value decomposition (T-SVD) regression method for learning such a model from data. Extensive simulations demonstrate that this method offers improved computational speed and higher sensitivity and specificity over competing approaches. The method is used to analyze microRNA (miRNA) and long noncoding RNA (lncRNA) data from The Cancer Genome Atlas (TCGA) consortium. The analysis yields previously unidentified insights into the combinatorial regulation of gene expression by noncoding RNAs, as well as findings that are supported by evidence from the literature. PMID:25331876

  18. Apocrine hidrocystoma arising from nevus sebaceous on the scalp.

    PubMed

    Tejaswi, Cherukuri; Rangaraj, Murugaiyan; Karthikeyan, Kaliaperumal

    2016-01-01

    Nevus sebaceous is a hamartoma with an uneventful course since birth but many benign or malignant tumors are known to develop in about one third of the patients. A 37-year-old woman with asymptomatic hairless raised lesion over the scalp since birth presented with change in the morphology of the lesions associated with itching and irritation since one month. On examination, multiple well-defined hyperpigmented verrucous plaques coalescing with each other were seen over the right parietal scalp associated with alopecia. A single well-defined soft skin-colored cystic swelling of size 1 × 2 cm was seen interspersed within the plaque. After a clinical diagnosis of nevus sebaceous, a biopsy of the cyst was done, which revealed a large cyst lined by columnar and myoepithelial cells in the dermis. The columnar cells at a few places showed "decapitation secretion" giving the impression of apocrine hidrocystoma. Post-excision of the cyst, biopsy of the entire nevus was done and the histopathological diagnosis correlated with the clinical diagnosis of nevus sebaceous. Apocrine hidrocystoma developing from a sebaceous nevus over the scalp is a rarity with only three other cases of it arising on the scalp being reported and none of them developed from a sebaceous nevus. PMID:27057493

  19. Apocrine hidrocystoma arising from nevus sebaceous on the scalp

    PubMed Central

    Tejaswi, Cherukuri; Rangaraj, Murugaiyan; Karthikeyan, Kaliaperumal

    2016-01-01

    Nevus sebaceous is a hamartoma with an uneventful course since birth but many benign or malignant tumors are known to develop in about one third of the patients. A 37-year-old woman with asymptomatic hairless raised lesion over the scalp since birth presented with change in the morphology of the lesions associated with itching and irritation since one month. On examination, multiple well-defined hyperpigmented verrucous plaques coalescing with each other were seen over the right parietal scalp associated with alopecia. A single well-defined soft skin-colored cystic swelling of size 1 × 2 cm was seen interspersed within the plaque. After a clinical diagnosis of nevus sebaceous, a biopsy of the cyst was done, which revealed a large cyst lined by columnar and myoepithelial cells in the dermis. The columnar cells at a few places showed “decapitation secretion” giving the impression of apocrine hidrocystoma. Post-excision of the cyst, biopsy of the entire nevus was done and the histopathological diagnosis correlated with the clinical diagnosis of nevus sebaceous. Apocrine hidrocystoma developing from a sebaceous nevus over the scalp is a rarity with only three other cases of it arising on the scalp being reported and none of them developed from a sebaceous nevus. PMID:27057493

  20. The complex spectrum of forensic issues arising from obesity.

    PubMed

    Byard, Roger W

    2012-12-01

    The increasing numbers of obese and morbidly obese individuals in the community are having a direct effect on forensic facilities. In addition to having to install more robust equipment for handling large bodies, the quality of autopsy examinations may be reduced by the physical difficulties that arise in trying to position bodies correctly so that normal examinations can proceed. Accelerated putrefaction is often an added complication. Metabolic disturbances resulting from obesity increase susceptibility to a range of conditions that are associated with sudden and unexpected death, and surgery may have increased complications. The rates of a number of different malignancies, including lymphoma, leukemia, melanoma and multiple myeloma, and carcinomas of the esophagus, stomach, colon, gallbladder, thyroid, prostate, breast and endometrium, are increased. In addition, obese individuals have higher rates of diabetes mellitus, and sepsis. The unexpected collapse of an obese individual should raise the possibility of a wide range of conditions, many of which may be more difficult to demonstrate at autopsy than in an individual with a normal body mass index. Although sudden cardiac death due to cardiomegaly, pulmonary thromboembolism, or ischemic heart disease may be the most probable diagnosis in an unexpected collapse, the range of possible underlying conditions is extensive and often only determinable after full postmortem examination. PMID:22383171

  1. Cochlear neuropathy and the coding of supra-threshold sound

    PubMed Central

    Bharadwaj, Hari M.; Verhulst, Sarah; Shaheen, Luke; Liberman, M. Charles; Shinn-Cunningham, Barbara G.

    2014-01-01

    Many listeners with hearing thresholds within the clinically normal range nonetheless complain of difficulty hearing in everyday settings and understanding speech in noise. Converging evidence from human and animal studies points to one potential source of such difficulties: differences in the fidelity with which supra-threshold sound is encoded in the early portions of the auditory pathway. Measures of auditory subcortical steady-state responses (SSSRs) in humans and animals support the idea that the temporal precision of the early auditory representation can be poor even when hearing thresholds are normal. In humans with normal hearing thresholds (NHTs), paradigms that require listeners to make use of the detailed spectro-temporal structure of supra-threshold sound, such as selective attention and discrimination of frequency modulation (FM), reveal individual differences that correlate with subcortical temporal coding precision. Animal studies show that noise exposure and aging can cause a loss of a large percentage of auditory nerve fibers (ANFs) without any significant change in measured audiograms. Here, we argue that cochlear neuropathy may reduce encoding precision of supra-threshold sound, and that this manifests both behaviorally and in SSSRs in humans. Furthermore, recent studies suggest that noise-induced neuropathy may be selective for higher-threshold, lower-spontaneous-rate nerve fibers. Based on our hypothesis, we suggest some approaches that may yield particularly sensitive, objective measures of supra-threshold coding deficits that arise due to neuropathy. Finally, we comment on the potential clinical significance of these ideas and identify areas for future investigation. PMID:24600357

  2. Cochlear neuropathy and the coding of supra-threshold sound.

    PubMed

    Bharadwaj, Hari M; Verhulst, Sarah; Shaheen, Luke; Liberman, M Charles; Shinn-Cunningham, Barbara G

    2014-01-01

    Many listeners with hearing thresholds within the clinically normal range nonetheless complain of difficulty hearing in everyday settings and understanding speech in noise. Converging evidence from human and animal studies points to one potential source of such difficulties: differences in the fidelity with which supra-threshold sound is encoded in the early portions of the auditory pathway. Measures of auditory subcortical steady-state responses (SSSRs) in humans and animals support the idea that the temporal precision of the early auditory representation can be poor even when hearing thresholds are normal. In humans with normal hearing thresholds (NHTs), paradigms that require listeners to make use of the detailed spectro-temporal structure of supra-threshold sound, such as selective attention and discrimination of frequency modulation (FM), reveal individual differences that correlate with subcortical temporal coding precision. Animal studies show that noise exposure and aging can cause a loss of a large percentage of auditory nerve fibers (ANFs) without any significant change in measured audiograms. Here, we argue that cochlear neuropathy may reduce encoding precision of supra-threshold sound, and that this manifests both behaviorally and in SSSRs in humans. Furthermore, recent studies suggest that noise-induced neuropathy may be selective for higher-threshold, lower-spontaneous-rate nerve fibers. Based on our hypothesis, we suggest some approaches that may yield particularly sensitive, objective measures of supra-threshold coding deficits that arise due to neuropathy. Finally, we comment on the potential clinical significance of these ideas and identify areas for future investigation. PMID:24600357

  3. Bayesian estimation of dose thresholds

    NASA Technical Reports Server (NTRS)

    Groer, P. G.; Carnes, B. A.

    2003-01-01

    An example is described of Bayesian estimation of radiation absorbed dose thresholds (subsequently simply referred to as dose thresholds) using a specific parametric model applied to a data set on mice exposed to 60Co gamma rays and fission neutrons. A Weibull based relative risk model with a dose threshold parameter was used to analyse, as an example, lung cancer mortality and determine the posterior density for the threshold dose after single exposures to 60Co gamma rays or fission neutrons from the JANUS reactor at Argonne National Laboratory. The data consisted of survival, censoring times and cause of death information for male B6CF1 unexposed and exposed mice. The 60Co gamma whole-body doses for the two exposed groups were 0.86 and 1.37 Gy. The neutron whole-body doses were 0.19 and 0.38 Gy. Marginal posterior densities for the dose thresholds for neutron and gamma radiation were calculated with numerical integration and found to have quite different shapes. The density of the threshold for 60Co is unimodal with a mode at about 0.50 Gy. The threshold density for fission neutrons declines monotonically from a maximum value at zero with increasing doses. The posterior densities for all other parameters were similar for the two radiation types.

  4. Threshold models in radiation carcinogenesis

    SciTech Connect

    Hoel, D.G.; Li, P.

    1998-09-01

    Cancer incidence and mortality data from the atomic bomb survivors cohort has been analyzed to allow for the possibility of a threshold dose response. The same dose-response models as used in the original papers were fit to the data. The estimated cancer incidence from the fitted models over-predicted the observed cancer incidence in the lowest exposure group. This is consistent with a threshold or nonlinear dose-response at low-doses. Thresholds were added to the dose-response models and the range of possible thresholds is shown for both solid tumor cancers as well as the different leukemia types. This analysis suggests that the A-bomb cancer incidence data agree more with a threshold or nonlinear dose-response model than a purely linear model although the linear model is statistically equivalent. This observation is not found with the mortality data. For both the incidence data and the mortality data the addition of a threshold term significantly improves the fit to the linear or linear-quadratic dose response for both total leukemias and also for the leukemia subtypes of ALL, AML, and CML.

  5. Kaon Thresholds and Two-Flavor Chiral Expansions for Hyperons

    SciTech Connect

    Fu-Jiun Jiang, Brian C. Tiburzi, Andre Walker-Loud

    2011-01-01

    Two-flavor chiral expansions provide a useful perturbative framework to study hadron properties. Such expansions should exhibit marked improvement over the conventional three-flavor chiral expansion. Although one can theoretically formulate two-flavor theories for the various hyperon multiplets, the nearness of kaon thresholds can seriously undermine the effectiveness of the perturbative expansion in practice. We investigate the importance of virtual kaon thresholds on hyperon properties, specifically their masses and isovector axial charges. Using a three-flavor expansion that includes SU(3) breaking effects, we uncover the underlying expansion parameter governing the description of virtual kaon thresholds. For spin-half hyperons, this expansion parameter is quite small. Consequently virtual kaon contributions are well described in the two-flavor theory by terms analytic in the pion mass-squared. For spin three-half hyperons, however, one is closer to the kaon production threshold, and the expansion parameter is not as small. Breakdown of SU(2) chiral perturbation theory is shown to arise from a pole in the expansion parameter associated with the kaon threshold. Estimating higher-order corrections to the expansion parameter is necessary to ascertain whether the two-flavor theory of spin three-half hyperons remains perturbative. We find that, despite higher-order corrections, there is a useful perturbative expansion for the masses and isovector axial charges of both spin-half and spin three-half hyperons.

  6. Retronasal smell and detection thresholds of iron and copper salts.

    PubMed

    Epke, Effie M; Lawless, Harry T

    2007-10-22

    Iron and copper salts, when placed in the mouth, may give rise to odorous compounds which complicate their functioning as chemical stimuli. The contribution of retronasal smell to perception of these metal salts at threshold has not been determined. Detection thresholds of the sulfate and chloride salts of ferrous iron and copper, and sodium chloride (as a control) were determined using a modified forced-choice ascending method of limits, with and without nasal occlusion. Threshold values were calculated from geometric means of individual estimates, and from interpolation on logistic regression and percent correct plots. Nasal occlusion raised thresholds for iron salts and copper but not sodium. The geometric mean detection thresholds with the nose open were 30, 64, 7.8, and 8.2 microM for FeSO(4), FeCl(2), CuSO(4), CuCl(2), respectively but rose to 160, 227, 24.6 and 15.6 with the nose closed. Metal salts of both iron and copper create a retronasally perceived olfactory stimulus at low concentration levels, probably arising from lipid oxidation products generated in the mouth. PMID:17532013

  7. Retronasal Smell and Detection Thresholds of Iron and Copper Salts

    PubMed Central

    Epke, Effie M.; Lawless, Harry T.

    2016-01-01

    Iron and copper salts, when placed in the mouth, may give rise to odorous compounds which complicate their functioning as chemical stimuli. The contribution of retronasal smell to perception of these metal salts at threshold has not been determined. Detection thresholds of the sulfate and chloride salts of ferrous iron and copper, and sodium chloride (as a control) were determined using a modified forced-choice ascending method of limits, with and without nasal occlusion. Threshold values were calculated from geometric means of individual estimates, and from interpolation on logistic regression and percent correct plots. Nasal occlusion raised thresholds for iron salts and copper but not sodium. The geometric mean detection thresholds with the nose open were 30, 64, 7.8, and 8.2 μM for FeSO4, FeCl2, CuSO4, CuCl2, respectively but rose to 160, 227, 24.6 and 15.6 with the nose closed. Metal salts of both iron and copper create a retronasally perceived olfactory stimulus at low concentration levels, probably arising from lipid oxidation products generated in the mouth. PMID:17532013

  8. Thresholds for color discrimination in English and Korean speakers.

    PubMed

    Roberson, Debi; Hanley, J Richard; Pak, Hyensou

    2009-09-01

    Categorical perception (CP) is said to occur when a continuum of equally spaced physical changes is perceived as unequally spaced as a function of category membership (Harnad, S. (Ed.) (1987). Psychophysical and cognitive aspects of categorical perception: A critical overview. Cambridge: Cambridge University Press). A common suggestion is that CP for color arises because perception is qualitatively distorted when we learn to categorize a dimension. Contrary to this view, we here report that English speakers show no evidence of lowered discrimination thresholds at the boundaries between blue and green categories even though CP is found at these boundaries in a supra-threshold task. Furthermore, there is no evidence of different discrimination thresholds between individuals from two language groups (English and Korean) who use different color terminology in the blue-green region and have different supra-threshold boundaries. Our participants' just noticeable difference (JND) thresholds suggest that they retain a smooth continuum of perceptual space that is not warped by stretching at category boundaries or by within-category compression. At least for the domain of color, categorical perception appears to be a categorical, but not a perceptual phenomenon. PMID:19619872

  9. Network Structures Arising from Spike-Timing Dependent Plasticity

    NASA Astrophysics Data System (ADS)

    Babadi, Baktash

    Spike-timing dependent plasticity (STDP), a widespread synaptic modification mechanism, is sensitive to correlations between presynaptic spike trains, and organizes neural circuits in functionally useful ways. In this dissertation, I study the structures arising from STDP in a population of synapses with an emphasis on the interplay between synaptic stability and Hebbian competition, explained in Chapter 1. Starting from the simplest description of STDP which relates synaptic modification to the intervals between pairs of pre- and postsynaptic spikes, I show in Chapter 2 that stability and Hebbian competition are incompatible in this class of "pair-based" STDP models, either when hard bounds or soft bounds are imposed to the synapses. In chapter 3, I propose an alternative biophysically inspired method for imposing bounds to synapses, i.e. introducing a small temporal shift in the STDP window. Shifted STDP overcomes the incompatibility of synaptic stability and competition and can implement both Hebbian and anti-Hebbian forms of competitive plasticity. In light of experiments the explored a variety of spike patterns, STDP models have been augmented to account for interactions between multiple pre- and postsynaptic action potentials. In chapter 4, I study the stability/competition interplay in three different proposed multi-spike models of STDP. I show that the "triplet model" leads to a partially steady-state distribution of synaptic weights and induces Hebbian competition. The "suppression model" develops a stable distribution of weights when the average weight is high and shows predominantly anti-Hebbian competition. The "NMDAR-based" model can lead to either stable or partially stable synaptic weight distribution and exhibits both Hebbian and anti-Hebbian competition, depending on the parameters. I conclude that multi-spike STDP models can produce radically different effects at the population level depending on how they implement multi-spike interactions

  10. Guidelines for Auditory Threshold Measurement for Significant Threshold Shift.

    PubMed

    Campbell, Kathleen; Hammill, Tanisha; Hoffer, Michael; Kil, Jonathan; Le Prell, Colleen

    2016-09-01

    The purpose of this article is to provide guidelines for determining a Significant Noise-Induced Threshold Shift in clinical trials involving human populations. The article reviews recommendations for the standards to be referenced for human subjects, equipment, test environment, and personnel. Additional guidelines for military populations are provided. Guidelines for the calibration of audiometers, sound booth noise levels, and immitance equipment are provided. In addition the guidance provides specific suggestions for the subjects history before study onset, and otoscopy.Test frequencies for threshold determination and methods of threshold determination are reviewed for both air conduction and bone conduction for both baseline testing and later determination of either a temporary (TTS) or permanent threshold shift (PTS). Once a Significant Noise-Induced Threshold Shift has been determined, subjects should be retested, conductive component should be ruled out or addressed, and the subject should be counseled or referred for additional medical evaluation. Guidance for reporting procedures and the computerized study database are described. Finally, experimental designs suggested for noise-induced otoprotection clinical trials are described. PMID:27518134

  11. 32 CFR 537.19 - Demands arising from maritime claims.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Demands arising from maritime claims. 537.19 Section 537.19 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS CLAIMS ON BEHALF OF THE UNITED STATES § 537.19 Demands arising from maritime claims. (a) It is essential that Army claims personnel...

  12. 32 CFR 537.19 - Demands arising from maritime claims.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 32 National Defense 3 2011-07-01 2009-07-01 true Demands arising from maritime claims. 537.19 Section 537.19 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY CLAIMS AND ACCOUNTS CLAIMS ON BEHALF OF THE UNITED STATES § 537.19 Demands arising from maritime claims. (a) It is essential that Army claims personnel...

  13. Single-unit activity, threshold crossings, and local field potentials in motor cortex differentially encode reach kinematics.

    PubMed

    Perel, Sagi; Sadtler, Patrick T; Oby, Emily R; Ryu, Stephen I; Tyler-Kabara, Elizabeth C; Batista, Aaron P; Chase, Steven M

    2015-09-01

    A diversity of signals can be recorded with extracellular electrodes. It remains unclear whether different signal types convey similar or different information and whether they capture the same or different underlying neural phenomena. Some researchers focus on spiking activity, while others examine local field potentials, and still others posit that these are fundamentally the same signals. We examined the similarities and differences in the information contained in four signal types recorded simultaneously from multielectrode arrays implanted in primary motor cortex: well-isolated action potentials from putative single units, multiunit threshold crossings, and local field potentials (LFPs) at two distinct frequency bands. We quantified the tuning of these signal types to kinematic parameters of reaching movements. We found 1) threshold crossing activity is not a proxy for single-unit activity; 2) when examined on individual electrodes, threshold crossing activity more closely resembles LFP activity at frequencies between 100 and 300 Hz than it does single-unit activity; 3) when examined across multiple electrodes, threshold crossing activity and LFP integrate neural activity at different spatial scales; and 4) LFP power in the "beta band" (between 10 and 40 Hz) is a reliable indicator of movement onset but does not encode kinematic features on an instant-by-instant basis. These results show that the diverse signals recorded from extracellular electrodes provide somewhat distinct and complementary information. It may be that these signal types arise from biological phenomena that are partially distinct. These results also have practical implications for harnessing richer signals to improve brain-machine interface control. PMID:26133797

  14. Damage thresholds for terahertz radiation

    NASA Astrophysics Data System (ADS)

    Dalzell, Danielle R.; McQuade, Jill; Vincelette, Rebecca; Ibey, Bennet; Payne, Jason; Thomas, Robert; Roach, W. P.; Roth, Caleb L.; Wilmink, Gerald J.

    2010-02-01

    Several international organizations establish minimum safety standards to ensure that workers and the general population are protected against adverse health effects associated with electromagnetic radiation. Suitable standards are typically defined using published experimental data. To date, few experimental studies have been conducted at Terahertz (THz) frequencies, and as a result, current THz standards have been defined using extrapolated estimates from neighboring spectral regions. In this study, we used computational modeling and experimental approaches to determine tissue-damage thresholds at THz frequencies. For the computational modeling efforts, we used the Arrhenius damage integral to predict damage-thresholds. We determined thresholds experimentally for both long (minutes) and short (seconds) THz exposures. For the long exposure studies, we used an in-house molecular gas THz laser (υ= 1.89 THz, 189.92 mW/cm2, 10 minutes) and excised porcine skin. For the short exposure studies, we used the Free Electron Laser (FEL) at Jefferson Laboratory (υ= 0.1-1.0 THz, 2.0-14.0 mW/cm2, 2 seconds) and wet chamois cloths. Thresholds were determined using conventional damage score determination and probit analysis techniques, and tissue temperatures were measured using infrared thermographic techniques. We found that the FEL was ideal for tissue damage studies, while our in-house THz source was not suitable to determine tissue damage thresholds. Using experimental data, the tissue damage threshold (ED50) was determined to be 7.16 W/cm2. This value was in well agreement with that predicted using our computational models. We hope that knowledge of tissue-damage thresholds at THz frequencies helps to ensure the safe use of THz radiation.

  15. 32 CFR 536.111 - Investigation of claims arising under international agreements (for those claims arising in the...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 32 National Defense 3 2012-07-01 2009-07-01 true Investigation of claims arising under international agreements (for those claims arising in the United States). 536.111 Section 536.111 National... UNITED STATES Claims Cognizable Under International Agreements § 536.111 Investigation of claims...

  16. 32 CFR 536.111 - Investigation of claims arising under international agreements (for those claims arising in the...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 32 National Defense 3 2014-07-01 2014-07-01 false Investigation of claims arising under international agreements (for those claims arising in the United States). 536.111 Section 536.111 National... UNITED STATES Claims Cognizable Under International Agreements § 536.111 Investigation of claims...

  17. [Mesorectal Lymph Node Metastasis Arising from Rectal Invasion by an Ovarian Cancer--A Case Report].

    PubMed

    Mizuki, Toru; Shimada, Yoshifumi; Yagi, Yutaka; Tajima, Yosuke; Nakano, Mae; Nakano, Masato; Tatsuda, Kumiko; Ishikawa, Takashi; Sakata, Jun; Kameyama, Hitoshi; Kobayashi, Takashi; Kosugi, Shin-ichi; Koyama, Yu; Wakai, Toshifumi; Enomoto, Takayuki

    2015-11-01

    A 58-year-old woman presenting with abdominal distension was diagnosed with a tumor in the right ovary. A chest-abdominal-pelvic computed tomography scan revealed multiple lung metastases, multiple liver metastases, and peritoneal dissemination. Invasion of the rectum by peritoneal dissemination of the Douglas' pouch was suspected. She was diagnosed with Stage Ⅳ right ovarian cancer and was treated with preoperative chemotherapy. After chemotherapy, debulking surgery of the abdominal cavity (total hysterectomy, bilateral salpingo-oophorectomy, partial omentectomy, and Hartmann's procedure) was performed. Because there was swelling observed in multiple mesorectal lymph nodes, lymph node dissection was performed based on methods used for rectal cancer surgery. Postoperative histopathological examination revealed multiple mesorectal lymph node metastases arising from ovarian cancer. We suggest that mesorectal lymph node dissection be considered a part of debulking surgery for ovarian cancers that have invaded the rectum. PMID:26805344

  18. Neutrino floor at ultralow threshold

    NASA Astrophysics Data System (ADS)

    Strigari, Louis E.

    2016-05-01

    By lowering their energy threshold, direct dark matter searches can reach the neutrino floor with experimental technology that is now in development. The 7Be flux can be detected with ˜10 eV nuclear recoil energy threshold and 50 kg/yr exposure. The p e p flux can be detected with ˜3 ton/yr exposure, and the first detection of the CNO flux is possible with similar exposure. The p p flux can be detected with threshold of ˜eV and only ˜ kg /yr exposure. These can be the first pure neutral current measurements of the low-energy solar neutrino flux. Measuring this flux is important for low mass dark matter searches and for understanding the solar interior.

  19. Explosive percolation in thresholded networks

    NASA Astrophysics Data System (ADS)

    Hayasaka, Satoru

    2016-06-01

    Explosive percolation in a network is a phase transition where a large portion of nodes becomes connected with an addition of a small number of edges. Although extensively studied in random network models and reconstructed real networks, explosive percolation has not been observed in a more realistic scenario where a network is generated by thresholding a similarity matrix describing between-node associations. In this report, I examine construction schemes of such thresholded networks, and demonstrate that explosive percolation can be observed by introducing edges in a particular order.

  20. Surface characterizations of color threshold

    NASA Technical Reports Server (NTRS)

    Poirson, Allen B.; Wandell, Brian A.; Varner, Denise C.; Brainard, David H.

    1990-01-01

    The paper evaluates how well three different parametric shapes, ellipsoids, rectangles, and parallelograms, serve as models of three-dimentional detection contours. The constraints of the procedures for deriving the best-fitting shapes on inferences about the theoretical visual detection mechanisms are described. Results of two statistical tests show that only the parallelogram fits the data with more precision than the variance in repeated threshold measurements, and thus provides a slightly better fit than the other two shapes. Nevertheless it does not serve as a better guide than the ellipsoidal model for interpolating from the measurements to thresholds in novel color directions.

  1. Thresholds in chemical respiratory sensitisation.

    PubMed

    Cochrane, Stella A; Arts, Josje H E; Ehnes, Colin; Hindle, Stuart; Hollnagel, Heli M; Poole, Alan; Suto, Hidenori; Kimber, Ian

    2015-07-01

    There is a continuing interest in determining whether it is possible to identify thresholds for chemical allergy. Here allergic sensitisation of the respiratory tract by chemicals is considered in this context. This is an important occupational health problem, being associated with rhinitis and asthma, and in addition provides toxicologists and risk assessors with a number of challenges. In common with all forms of allergic disease chemical respiratory allergy develops in two phases. In the first (induction) phase exposure to a chemical allergen (by an appropriate route of exposure) causes immunological priming and sensitisation of the respiratory tract. The second (elicitation) phase is triggered if a sensitised subject is exposed subsequently to the same chemical allergen via inhalation. A secondary immune response will be provoked in the respiratory tract resulting in inflammation and the signs and symptoms of a respiratory hypersensitivity reaction. In this article attention has focused on the identification of threshold values during the acquisition of sensitisation. Current mechanistic understanding of allergy is such that it can be assumed that the development of sensitisation (and also the elicitation of an allergic reaction) is a threshold phenomenon; there will be levels of exposure below which sensitisation will not be acquired. That is, all immune responses, including allergic sensitisation, have threshold requirement for the availability of antigen/allergen, below which a response will fail to develop. The issue addressed here is whether there are methods available or clinical/epidemiological data that permit the identification of such thresholds. This document reviews briefly relevant human studies of occupational asthma, and experimental models that have been developed (or are being developed) for the identification and characterisation of chemical respiratory allergens. The main conclusion drawn is that although there is evidence that the

  2. Photovoltaic multiplicities

    NASA Astrophysics Data System (ADS)

    Queisser, Hans J.

    1997-04-01

    A multicell solar energy converter, produced in 1959/60 at the Shockley Transistor Corporation, is reviewed. The feasibility of this device, one of the first involving principles of Si integrated circuits, was demonstrated in anticipation of large-area Si sheets, to be pulled from Si/Pb binary melts. Secondly, the generation of multiple carrier pairs by absorption of merely one photon is discussed. Experiments on high-quality Si solar cells demonstrated this effect, which relies on inverse Auger generation. In principle, much higher maximal conversion efficiencies would be possible; novel criteria for materials optimization result. The new challenge of the inverse band structure problem arises. Finally, multistage optical transitions via deep centers in solar cells are briefly appraised.

  3. Threshold units: A correct metric for reaction time?

    PubMed Central

    Zele, Andrew J.; Cao, Dingcai; Pokorny, Joel

    2007-01-01

    Purpose To compare reaction time (RT) to rod incremental and decremental stimuli expressed in physical contrast units or psychophysical threshold units. Methods Rod contrast detection thresholds and suprathreshold RTs were measured for Rapid-On and Rapid-Off ramp stimuli. Results Threshold sensitivity to Rapid-Off stimuli was higher than to Rapid-On stimuli. Suprathreshold RTs specified in Weber contrast for Rapid-Off stimuli were shorter than for Rapid-On stimuli. Reaction time data expressed in multiples of threshold reversed the outcomes: Reaction times for Rapid-On stimuli were shorter than those for Rapid-Off stimuli. The use of alternative contrast metrics also failed to equate RTs. Conclusions A case is made that the interpretation of RT data may be confounded when expressed in threshold units. Stimulus energy or contrast is the only metric common to the response characteristics of the cells underlying speeded responses. The use of threshold metrics for RT can confuse the interpretation of an underlying physiological process. PMID:17240416

  4. Localised fibrous mesothelioma arising in an intralobar pulmonary sequestration.

    PubMed Central

    Paksoy, N; Demircan, A; Altiner, M; Artvinli, M

    1992-01-01

    A localised fibrous mesothelioma arising from an intralobar lung sequestration occurred in a 64 year old Turkish woman. This appears to be the first report of a mesothelioma occurring within a pulmonary sequestration. Images PMID:1481189

  5. MYC Amplification in Angiosarcoma Arising from an Arteriovenous Graft Site

    PubMed Central

    Paral, Kristen M.; Raca, Gordana; Krausz, Thomas

    2015-01-01

    Angiosarcoma arising in association with an arteriovenous graft (AVG) or fistula is a unique clinicopathologic scenario that appears to be gaining recognition in the literature. Among reported cases, none has described high-level MYC gene amplification, a genetic aberration that is increasingly unifying the various clinicopathologic subdivisions of angiosarcoma. We therefore report the MYC gene status in a case of angiosarcoma arising at an AVG site. PMID:26682080

  6. New states above charm threshold

    SciTech Connect

    Eichten, Estia J.; Lane, Kenneth; Quigg, Chris; /Fermilab

    2005-11-01

    We revise and extend expectations for the properties of charmonium states that lie above charm threshold, in light of new experimental information. We refine the Cornell coupled-channel model for the coupling of c{bar c} levels to two-meson states, defining resonance masses and widths by pole positions in the complex energy plane, and suggest new targets for experiment.

  7. Estimating Conservation Thresholds on Rangelands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Conservation Effects Assessment Project (CEAP) is a multi-agency effort designed to quantify the environmental and economic impacts of land conservation practices. One of USDA’s goals is to identify Conservation Thresholds, the point at which accelerated erosion occurs, and to examine the usefu...

  8. Threshold Concepts and Pedagogic Representation

    ERIC Educational Resources Information Center

    Meyer, Jan H. F.

    2016-01-01

    Purpose: The purpose of this paper is to present a brief exposure to the development of the threshold concepts framework (TCF), the intention being to illuminate for interested readers a broader landscape of research activity than that perhaps conveyed by the individual contributions to this special edition. Design/Methodology/Approach: There is…

  9. Crossing Thresholds in Academic Reading

    ERIC Educational Resources Information Center

    Abbott, Rob

    2013-01-01

    This paper looks at the conceptual thresholds in relation to academic reading which might be crossed by undergraduate English Literature students. It is part of a wider study following 16 students through three years of undergraduate study. It uses theoretical ideas from Bakhtin and Foucault to analyse interviews with English lecturers. It…

  10. Superlinear threshold detectors in quantum cryptography

    SciTech Connect

    Lydersen, Lars; Maroey, Oystein; Skaar, Johannes; Makarov, Vadim; Jain, Nitin; Wittmann, Christoffer; Marquardt, Christoph; Leuchs, Gerd

    2011-09-15

    We introduce the concept of a superlinear threshold detector, a detector that has a higher probability to detect multiple photons if it receives them simultaneously rather than at separate times. Highly superlinear threshold detectors in quantum key distribution systems allow eavesdropping the full secret key without being revealed. Here, we generalize the detector control attack, and analyze how it performs against quantum key distribution systems with moderately superlinear detectors. We quantify the superlinearity in superconducting single-photon detectors based on earlier published data, and gated avalanche photodiode detectors based on our own measurements. The analysis shows that quantum key distribution systems using detector(s) of either type can be vulnerable to eavesdropping. The avalanche photodiode detector becomes superlinear toward the end of the gate. For systems expecting substantial loss, or for systems not monitoring loss, this would allow eavesdropping using trigger pulses containing less than 120 photons per pulse. Such an attack would be virtually impossible to catch with an optical power meter at the receiver entrance.

  11. Neural Field Models with Threshold Noise.

    PubMed

    Thul, Rüdiger; Coombes, Stephen; Laing, Carlo R

    2016-12-01

    The original neural field model of Wilson and Cowan is often interpreted as the averaged behaviour of a network of switch like neural elements with a distribution of switch thresholds, giving rise to the classic sigmoidal population firing-rate function so prevalent in large scale neuronal modelling. In this paper we explore the effects of such threshold noise without recourse to averaging and show that spatial correlations can have a strong effect on the behaviour of waves and patterns in continuum models. Moreover, for a prescribed spatial covariance function we explore the differences in behaviour that can emerge when the underlying stationary distribution is changed from Gaussian to non-Gaussian. For travelling front solutions, in a system with exponentially decaying spatial interactions, we make use of an interface approach to calculate the instantaneous wave speed analytically as a series expansion in the noise strength. From this we find that, for weak noise, the spatially averaged speed depends only on the choice of covariance function and not on the shape of the stationary distribution. For a system with a Mexican-hat spatial connectivity we further find that noise can induce localised bump solutions, and using an interface stability argument show that there can be multiple stable solution branches. PMID:26936267

  12. Theory of Mesoscopic Threshold Detectors of non-Gaussian Noise

    NASA Astrophysics Data System (ADS)

    Jordan, Andrew

    2009-03-01

    Recently, measurements of current fluctuations arising from the charge discreteness (shot noise) have become an invaluable tool in mesoscopic physics, the most noticeable achievement being the measurement of quasi-particle charge in the fractional quantum Hall state. Typically, shot noise experiments report measurements of the zero-frequency noise power, which is a characteristic of the Gaussian component of current fluctuations. A natural generalization of the noise power, the counting statistics of charge transmitted through a system, is interesting in itself, because it contains complete information about the electron transport on a long time scale. However, the measurement of non-Gaussian noise effects presents an experimental challenge because of the limitations imposed by the central limit theorem. This difficulty can be partly overcome by placing an auxiliary mesoscopic system (detector) very close to the noise source and arranging strong coupling to the noise. This leads to the idea of a threshold detector, which is able to measure rare current fluctuations. Its basic principle is analogous to a pole vault: A detection event occurs when the measured system variable exceeds a given threshold value. A natural candidate for such a threshold detector is a metastable system operating on an activation principle. By measuring the rate of switching out of the metastable state, information about the statistical properties of the noise driving the system may be extracted. This requires solving the Kramers' problem of noise-activated escape from a metastable state beyond the Gaussian noise approximation and investigating how the measurement circuit affects threshold detection.

  13. Inflection, canards and excitability threshold in neuronal models.

    PubMed

    Desroches, M; Krupa, M; Rodrigues, S

    2013-10-01

    A technique is presented, based on the differential geometry of planar curves, to evaluate the excitability threshold of neuronal models. The aim is to determine regions of the phase plane where solutions to the model equations have zero local curvature, thereby defining a zero-curvature (inflection) set that discerns between sub-threshold and spiking electrical activity. This transition can arise through a Hopf bifurcation, via the so-called canard explosion that happens in an exponentially small parameter variation, and this is typical for a large class of planar neuronal models (FitzHugh-Nagumo, reduced Hodgkin-Huxley), namely, type II neurons (resonators). This transition can also correspond to the crossing of the stable manifold of a saddle equilibrium, in the case of type I neurons (integrators). We compute inflection sets and study how well they approximate the excitability threshold of these neuron models, that is, both in the canard and in the non-canard regime, using tools from invariant manifold theory and singularity theory. With the latter, we investigate the topological changes that inflection sets undergo upon parameter variation. Finally, we show that the concept of inflection set gives a good approximation of the threshold in both the so-called resonator and integrator neuronal cases. PMID:22945512

  14. Multilayer multicast key management with threshold cryptography

    NASA Astrophysics Data System (ADS)

    Dexter, Scott D.; Belostotskiy, Roman; Eskicioglu, Ahmet M.

    2004-06-01

    The problem of distributing multimedia securely over the Internet is often viewed as an instance of secure multicast communication, in which multicast messages are protected by a group key shared among the group of clients. One important class of key management schemes makes use of a hierarchical key distribution tree. Constructing a hierarchical tree based on secret shares rather than keys yields a scheme that is both more flexible and provably secure. Both the key-based and share-based hierarchical key distribution tree techniques are designed for managing keys for a single data stream. Recent work shows how redundancies that arise when this scheme is extended to multi-stream (e.g. scalable video) applications may be exploited in the key-based system by viewing the set of clients as a "multi-group". In this paper, we present results from an adaptation of a multi-group key management scheme using threshold cryptography. We describe how the multi-group scheme is adapted to work with secret shares, and compare this scheme with a naíve multi-stream key-management solution by measuring performance across several critical parameters, including tree degree, multi-group size, and number of shares stored at each node.

  15. Rainfall thresholds for the initiation of landslides in Italy

    NASA Astrophysics Data System (ADS)

    Peruccacci, S.; Brunetti, M. T.; Rossi, M.; Guzzetti, F.

    2009-04-01

    Rainfall is a recognized trigger of landslides, and various investigators have long attempted to determine the amount of precipitation needed to trigger slope failures, and to establish rainfall thresholds for the initiation of landslides. Determining the amount of rainfall needed to trigger a landslide is a problem of both scientific and societal interest, and the literature on the topic is vast. In this work, we describe an attempt to establish rainfall intensity - duration (ID) thresholds for the initiation of landslides in Italy. For the purpose, we have compiled a database of 562 rainfall events that have resulted in landslides. The rainfall and landslide information was obtained by searching the literature, including international journals, proceedings of regional, national and international conferences, and national, regional, and local technical and event reports describing single or multiple rainfall-induced landslides. We plot the rainfall intensity-duration values in logarithmic coordinates, and we establish that with increased rainfall duration the minimum average intensity likely to trigger shallow slope failures decreases linearly, in the range of durations from 10 minutes to 4 days. Based on this observation, we determine minimum ID thresholds for the possible initiation of landslides. The threshold curves are obtained from the empirical rainfall data using two objective statistical techniques, one that exploits Bayesian inference and one that uses a modelling tool in the R statistical environment. The two procedures avoid subjectivity in the determination of the thresholds, a problem that affects several of the published rainfall thresholds for the initiation of landslides. To cope with differences in the intensity and duration of rainfall likely to result in slope failures in different climatic regions, we normalize the rainfall information. Normalization is performed using two climate indexes, the Mean Annual Precipitation (MAP) and the Rainy

  16. Hadronic resonances enhanced by thresholds

    NASA Astrophysics Data System (ADS)

    Caramés, T. F.; Valcarce, A.

    2016-07-01

    We present a neat example of a meson-baryon system where the vicinity of two different thresholds enhances the binding of a hadronic resonance, a pentaquark. As a consequence the pattern of states may change when moving among different flavor sectors, what poses a warning on naive extrapolations to heavy flavor sectors based on systematic expansions. For this purpose we simultaneously analyze the N D bar and NB two-hadron systems looking for possible bound states or resonances. When a resonance is controlled by a coupled-channel effect, going to a different flavor sector may enhance or diminish the binding. This effect may, for example, generate significant differences between the charmonium and bottomonium spectra above open-flavor thresholds or pentaquark states in the open-charm and open-bottom sectors.

  17. Low Threshold Quantum Dot Lasers.

    PubMed

    Iyer, Veena Hariharan; Mahadevu, Rekha; Pandey, Anshu

    2016-04-01

    Semiconductor quantum dots have replaced conventional inorganic phosphors in numerous applications. Despite their overall successes as emitters, their impact as laser materials has been severely limited. Eliciting stimulated emission from quantum dots requires excitation by intense short pulses of light typically generated using other lasers. In this Letter, we develop a new class of quantum dots that exhibit gain under conditions of extremely low levels of continuous wave illumination. We observe thresholds as low as 74 mW/cm(2) in lasers made from these materials. Due to their strong optical absorption as well as low lasing threshold, these materials could possibly convert light from diffuse, polychromatic sources into a laser beam. PMID:26978011

  18. Enhanced dynamic threshold voltage UTBB SOI nMOSFETs

    NASA Astrophysics Data System (ADS)

    Sasaki, K. R. A.; Manini, M. B.; Simoen, E.; Claeys, C.; Martino, J. A.

    2015-10-01

    This work aims to analyze the impact of the Ground Plane (GP) on a new generation of the dynamic threshold (DT2) operation in Ultra-thin Body and Buried Oxide (UTBB) SOI nMOSFETs. The DT2, using a short-circuit between the gate and the substrate contact, the enhanced dynamic threshold (eDT), where the substrate bias is a multiple value of the gate bias (VB = k × VG,k = 1,2,…,5), and the inverse eDT (with VG = k × VB) were compared to the conventional mode with grounded substrate. Although the improvement of the DT2 mode observed for devices with GP is lower, they presented lower short channel effects, mainly for shorter channel lengths. Regarding the direct and inverse eDT modes, a stronger dynamic threshold (DT) effect on devices with GP also results in better DC parameters such as lower subthreshold swing and higher maximum transconductance.

  19. Error threshold for the surface code in a superohmic environment

    NASA Astrophysics Data System (ADS)

    Lopez-Delgado, Daniel A.; Novais, E.; Mucciolo, Eduardo R.; Caldeira, Amir O.

    Using the Keldysh formalism, we study the fidelity of a quantum memory over multiple quantum error correction cycles when the physical qubits interact with a bosonic bath at zero temperature. For encoding, we employ the surface code, which has one of the highest error thresholds in the case of stochastic and uncorrelated errors. The time evolution of the fidelity of the resulting two-dimensional system is cast into a statistical mechanics phase transition problem on a three-dimensional spin lattice, and the error threshold is determined by the critical temperature of the spin model. For superohmic baths, we find that time does not affect the error threshold: its value is the same for one or an arbitrary number of quantum error correction cycles. Financial support Fapesp, and CNPq (Brazil).

  20. Analytical reduction of combinatorial complexity arising from multiple protein modification sites.

    PubMed

    Birtwistle, Marc R

    2015-02-01

    Combinatorial complexity is a major obstacle to ordinary differential equation (ODE) modelling of biochemical networks. For example, a protein with 10 sites that can each be unphosphorylated, phosphorylated or bound to adaptor protein requires 3(10) ODEs. This problem is often dealt with by making ad hoc assumptions which have unclear validity and disallow modelling of site-specific dynamics. Such site-specific dynamics, however, are important in many biological systems. We show here that for a common biological situation where adaptors bind modified sites, binding is slow relative to modification/demodification, and binding to one modified site hinders binding to other sites, for a protein with n modification sites and m adaptor proteins the number of ODEs needed to simulate the site-specific dynamics of biologically relevant, lumped bound adaptor states is independent of the number of modification sites and equal to m + 1, giving a significant reduction in system size. These considerations can be relaxed considerably while retaining reasonably accurate descriptions of the true system dynamics. We apply the theory to model, using only 11 ODEs, the dynamics of ligand-induced phosphorylation of nine tyrosines on epidermal growth factor receptor (EGFR) and primary recruitment of six signalling proteins (Grb2, PI3K, PLCγ1, SHP2, RasA1 and Shc1). The model quantitatively accounts for experimentally determined site-specific phosphorylation and dephosphorylation rates, differential affinities of binding proteins for the phosphorylated sites and binding protein expression levels. Analysis suggests that local concentration of site-specific phosphatases such as SHP2 in membrane subdomains by a factor of approximately 10(7) is critical for effective site-specific regulation. We further show how our framework can be extended with minimal effort to consider binding cooperativity between Grb2 and c-Cbl, which is important for receptor trafficking. Our theory has potentially broad application to reduce combinatorial complexity and allow practical simulation of a variety ODE models relevant to systems biology and pharmacology applications to allow exploration of key aspects of complexity that control signal flux. PMID:25519995

  1. Multiple coronary-cameral fistulas to the left ventricle arising from both coronary arteries

    PubMed Central

    Pathak, Ranjan; Giri, Smith; Hwang, Inyong; Alsafwah, Shadwan

    2016-01-01

    Coronary-cameral fistula (CCF) is an anomalous connection between a coronary artery and a cardiac chamber or major vessel, seen in about 0.8% of the cases undergoing coronary angiography. Most patients are asymptomatic and diagnosis is made incidentally during coronary angiography. We present an image case of CCF which was found incidentally during pre-liver transplantation work up. PMID:27406447

  2. Single-trial classification of near-infrared spectroscopy signals arising from multiple cortical regions.

    PubMed

    Schudlo, Larissa C; Chau, Tom

    2015-09-01

    Near-infrared spectroscopy (NIRS) brain-computer interface (BCI) studies have primarily made use of measurements taken from a single cortical area. In particular, the anterior prefrontal cortex has been the key area used for detecting higher-level cognitive task performance. However, mental task execution typically requires coordination between several, spatially-distributed brain regions. We investigated the value of expanding the area of interrogation to include NIRS measurements from both the prefrontal and parietal cortices to decode mental states. Hemodynamic activity was monitored at 46 locations over the prefrontal and parietal cortices using a continuous-wave near-infrared spectrometer while 11 able-bodied adults rested or performed either the verbal fluency task (VFT) or Stroop task. Offline classification was performed for the three possible binary problems using 25 iterations of bagging with a linear discriminant base classifier. Classifiers were trained on a 10 dimensional feature set. When all 46 measurement locations were considered for classification, average accuracies of 80.4±7.0%, 82.4±7.6%, and 82.8±5.9% in differentiating VFT vs rest, Stroop vs rest and VFT vs Stroop, respectively, were obtained. Relative to using measurements from the anterior PFC alone, an overall average improvement of 11.3% was achieved. Utilizing NIRS measurements from the prefrontal and parietal cortices can be of value in classifying mental states involving working memory and attention. NIRS-BCI accuracies may be improved by incorporating measurements from several, distinct cortical regions, rather than a single area alone. Further development of an NIRS-BCI supporting combinations of VFT, Stroop task and rest states is also warranted. PMID:25960315

  3. Roots at the Percolation Threshold

    NASA Astrophysics Data System (ADS)

    Kroener, E.; Ahmed, M. A.; Kaestner, A.; Vontobel, P.; Zarebanadkouki, M.; Carminati, A.

    2014-12-01

    Much of the carbon assimilated by plants during photosynthesis is lost to the soil via rhizodepositions. One component of rhizopdeposition is mucilage, a hydrogel that dramatically alters the soil physical properties. Mucilage was assumed to explain unexpectedly low rhizosphere rewetting rates during irrigation (Carminati et al. 2010) and temporarily water repellency in the rhizosphere after severe drying (Moradi et al. 2012).Here, we present an experimental and theoretical study for the rewetting behaviour of a soil mixed with mucilage, which was used as an analogue of the rhizosphere. Our samples were made of two layers of untreated soils separated by a thin layer (ca. 1 mm) of soil treated with mucilage. We prepared soil columns of varying particle size, mucilage concentration and height of the middle layer above the water table. The dry soil columns were re-wetted by capillary rise from the bottom.The rewetting of the middle layer showed a distinct dual behavior. For mucilage concentrations lower than a certain threshold, water could cross the thin layer almost immediately after rewetting of bulk soil. At slightly higher mucilage concentrations, the thin layer was almost impermeable. The mucilage concentration at the threshold strongly depended on particle size: the smaller the particle size the larger the soil specific surface and the more mucilage was needed to cover the entire particle surface and to induce water repellency.We applied a classic pore network model to simulate the experimental observations. In the model a certain fraction of nodes were randomly disconnected to reproduce the effect of mucilage in temporarily blocking the flow. The percolation model could qualitatively reproduce well the threshold characteristics of the experiments. Our experiments, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively

  4. The problem with multiple robots

    NASA Technical Reports Server (NTRS)

    Huber, Marcus J.; Kenny, Patrick G.

    1994-01-01

    The issues that can arise in research associated with multiple, robotic agents are discussed. Two particular multi-robot projects are presented as examples. This paper was written in the hope that it might ease the transition from single to multiple robot research.

  5. Pooling optimal combinations of energy thresholds in spectroscopic CT

    NASA Astrophysics Data System (ADS)

    Koenig, Thomas; Zuber, Marcus; Hamann, Elias; Runz, Armin; Fiederle, Michael; Baumbach, Tilo

    2014-03-01

    Photon counting detectors used in spectroscopic CT are often based on small pixels and therefore offer only limited space to include energy discriminators and their associated counters in each pixel cell. For this reason, it is important to make efficient use of the available energy discriminators in order to achieve an optimized material contrast at a radiation dose as low as possible. Unfortunately, the complexity of evaluating every possible combination of energy thresholds, given a fixed number of counters, rapidly increases with the resolution at which this search is performed, and makes brute-force approaches to this problem infeasible. In this work, we introduce methods from machine learning, in particular sparse regression, to perform a feature selection to determine optimal combinations of energy thresholds. We will demonstrate how methods enforcing row-sparsity on a linear regression's coefficient matrix can be applied to the multiple response problem in spectroscopic CT, i.e. the case in which a single set of energy thresholds is sought to simultaneously retrieve concentrations pertaining to a multitude of materials in an optimal way. These methods are applied to CT images experimentally obtained with a Medipix3RX detector operated in charge summing mode and with a CdTe sensor at a pixel pitch of 110μm. We show that the least absolute shrinkage and selection operator (lasso), generalized to the multiple response case, chooses four out of 20 possible threshold positions that allow discriminating PMMA, iodine and gadolinium in a contrast agent phantom at a higher accuracy than with equally spaced thresholds. Finally, we illustrate why it might be unwise to use a higher number of energy thresholds than absolutely necessary.

  6. Laparoscopic resection of a retroperitoneal hemangioma arising from ovarian vessels.

    PubMed

    Choi, Youn Seok; Oh, Hoon Kyu

    2009-01-01

    Hemangiomas are known to be common benign tumors. However, hemangiomas of female genital organs are very rare. Furthermore, a retroperitoneal hemangioma arising from ovarian vessels has never been reported. Here we report a case of a 29-year-old woman with a retroperitoneal cavernous hemangioma arising from the ovarian vessels of infundibulopelvic ligament, which was treated with laparoscopic resection. The operating time was 30 minutes, and resection was carried out with minimal blood loss. The postoperative period was uneventful, and the patient was discharged on postoperative day 3. Laparoscopic resection of this type of hemangioma is feasible. PMID:19896610

  7. Gastrointestinal Stromal Tumor Arising From a Gastric Duplication Cyst

    PubMed Central

    Machicado, Jorge; Davogustto, Giovanni

    2016-01-01

    Gastric duplication cysts (GDC) are rarely diagnosed in adults, but previous cases have been associated with malignancy. We present a case of gastrointestinal stromal tumor (GIST) arising from a GDC in a 71-year-old woman who presented with 3 years of early satiety, anorexia, abdominal distention, and weight loss. Abdominal CT showed a 9.3 x 5.2 x 9.5-cm well-circumscribed cystic mass arising 3 cm above the gastroduodenal junction. The cyst was resected, and histopathology was consistent with GDC. Future studies are needed to clarify the malignant potential of GDC and the molecular pathways for its development. PMID:27144196

  8. Setting conservation management thresholds using a novel participatory modeling approach.

    PubMed

    Addison, P F E; de Bie, K; Rumpff, L

    2015-10-01

    We devised a participatory modeling approach for setting management thresholds that show when management intervention is required to address undesirable ecosystem changes. This approach was designed to be used when management thresholds: must be set for environmental indicators in the face of multiple competing objectives; need to incorporate scientific understanding and value judgments; and will be set by participants with limited modeling experience. We applied our approach to a case study where management thresholds were set for a mat-forming brown alga, Hormosira banksii, in a protected area management context. Participants, including management staff and scientists, were involved in a workshop to test the approach, and set management thresholds to address the threat of trampling by visitors to an intertidal rocky reef. The approach involved trading off the environmental objective, to maintain the condition of intertidal reef communities, with social and economic objectives to ensure management intervention was cost-effective. Ecological scenarios, developed using scenario planning, were a key feature that provided the foundation for where to set management thresholds. The scenarios developed represented declines in percent cover of H. banksii that may occur under increased threatening processes. Participants defined 4 discrete management alternatives to address the threat of trampling and estimated the effect of these alternatives on the objectives under each ecological scenario. A weighted additive model was used to aggregate participants' consequence estimates. Model outputs (decision scores) clearly expressed uncertainty, which can be considered by decision makers and used to inform where to set management thresholds. This approach encourages a proactive form of conservation, where management thresholds and associated actions are defined a priori for ecological indicators, rather than reacting to unexpected ecosystem changes in the future. PMID:26040608

  9. VISUAL THRESHOLDS FOR SHEARING MOTION IN MONKEY AND MAN

    PubMed Central

    Golomb, B.; Andersen, R. A.; Nakayama, K.; MacLeod, D. I. A.; Wong, A.

    2016-01-01

    A reaction-time task was used to determine the visual motion thresholds in humans and in macaque monkeys for sinusoidally modulated shearing motion of a random dot display, It was found that humans and macaques were very similar in their spatial frequency sensitivity profiles for shearing motion. These profiles were of a U-shape for all human and monkey subjects tested. Temporal frequency, varied over a wide range, did not influence the shape of the spatial frequency sensitivity curve, but only the threshold amplitudes. The above results held both for single and multiple temporal cycles of shearing motion. Previous reports for the human, using these same shearing motion stimuli, indicated no increase in threshold at the lower spatial frequencies. The reason for this discrepancy is that thresholds in the previous studies were not determined at a low enough spatial frequency to see clearly this increase in thresholds. Because of the striking similarity of the data for man and macaque, it is suggested that similar neural mechanisms underly the shearing motion sensitivity of the two species. PMID:4024479

  10. Cascades in the Threshold Model for varying system sizes

    NASA Astrophysics Data System (ADS)

    Karampourniotis, Panagiotis; Sreenivasan, Sameet; Szymanski, Boleslaw; Korniss, Gyorgy

    2015-03-01

    A classical model in opinion dynamics is the Threshold Model (TM) aiming to model the spread of a new opinion based on the social drive of peer pressure. Under the TM a node adopts a new opinion only when the fraction of its first neighbors possessing that opinion exceeds a pre-assigned threshold. Cascades in the TM depend on multiple parameters, such as the number and selection strategy of the initially active nodes (initiators), and the threshold distribution of the nodes. For a uniform threshold in the network there is a critical fraction of initiators for which a transition from small to large cascades occurs, which for ER graphs is largerly independent of the system size. Here, we study the spread contribution of each newly assigned initiator under the TM for different initiator selection strategies for synthetic graphs of various sizes. We observe that for ER graphs when large cascades occur, the spread contribution of the added initiator on the transition point is independent of the system size, while the contribution of the rest of the initiators converges to zero at infinite system size. This property is used for the identification of large transitions for various threshold distributions. Supported in part by ARL NS-CTA, ARO, ONR, and DARPA.

  11. SER performance analysis of MPPM FSO system with three decision thresholds over exponentiated Weibull fading channels

    NASA Astrophysics Data System (ADS)

    Wang, Ping; Yang, Bensheng; Guo, Lixin; Shang, Tao

    2015-11-01

    In this work, the symbol error rate (SER) performance of the multiple pulse position modulation (MPPM) based free-space optical communication (FSO) system with three different decision thresholds, fixed decision threshold (FDT), optimized decision threshold (ODT) and dynamic decision threshold (DDT) over exponentiated Weibull (EW) fading channels has been investigated in detail. The effects of aperture averaging on each decision threshold under weak-to-strong turbulence conditions are further studied and compared. The closed-form SER expressions for three thresholds derived with the help of generalized Gauss-Laguerre quadrature rule are verified by the Monte Carlo simulations. This work is helpful for the design of receivers for FSO communication systems.

  12. 12 CFR 221.110 - Questions arising under this part.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 12 Banks and Banking 3 2013-01-01 2013-01-01 false Questions arising under this part. 221.110 Section 221.110 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM (CONTINUED) CREDIT BY BANKS AND PERSONS OTHER THAN BROKERS OR DEALERS FOR THE PURPOSE OF PURCHASING OR CARRYING MARGIN STOCK...

  13. 12 CFR 221.110 - Questions arising under this part.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 12 Banks and Banking 3 2014-01-01 2014-01-01 false Questions arising under this part. 221.110 Section 221.110 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL RESERVE SYSTEM (CONTINUED) CREDIT BY BANKS AND PERSONS OTHER THAN BROKERS OR DEALERS FOR THE PURPOSE OF PURCHASING OR CARRYING MARGIN STOCK...

  14. Transcultural Knowledge and Skills Transfer: Issues Arising from Evaluation Processes

    ERIC Educational Resources Information Center

    Green, Anita J.; Holloway, David G.

    2007-01-01

    The transfer of knowledge, policy and practice between nations increasingly involves knowledge of the theory and practice of evaluation. This article examines issues arising from the transcultural evaluation of a drug and alcohol misuse knowledge and skills transfer programme for nurses, nurse teachers and medical staff in the narcology service in…

  15. Adenomatoid Tumor of the Testis Arising From the Tunica Albuginea

    PubMed Central

    Sun, Andrew Y; Polackwich, A. Scott; Sabanegh, Jr, Edmund S

    2016-01-01

    Adenomatoid tumors are the most common paratesticular tumor. Although they primarily arise from the epididymis, they can rarely occur as an isolated intratesticular mass. These tumors are benign and surgical excision is curative. We present a case of a 36-year-old man diagnosed with an intratesticular adenomatoid tumor. PMID:27162515

  16. 12 CFR 221.110 - Questions arising under this part.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... CARRYING MARGIN STOCK (REGULATION U) Interpretations § 221.110 Questions arising under this part. (a) This part governs “any purpose credit” extended by a lender “secured directly or indirectly by margin stock... ultimate, of buying or carrying margin stock, “ with certain exceptions, and provides that the maximum...

  17. 12 CFR 221.110 - Questions arising under this part.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CARRYING MARGIN STOCK (REGULATION U) Interpretations § 221.110 Questions arising under this part. (a) This part governs “any purpose credit” extended by a lender “secured directly or indirectly by margin stock... ultimate, of buying or carrying margin stock, “ with certain exceptions, and provides that the maximum...

  18. Errors arising from incorrect orientation of E test strips.

    PubMed Central

    Hamilton-Miller, J M; Shah, S; Yam, T S

    1995-01-01

    Major errors arise if E test strips are placed upside down. Asymmetric zones, or no zone at all, may result. MICs indicated by upside-down tests were almost always considerably higher than true values. This situation differs markedly from that for conventional testing, where orientation of disks is not important. PMID:7665686

  19. Program For Thresholding In Digital Images

    NASA Technical Reports Server (NTRS)

    Nolf, Scott R.; Avis, Elizabeth L.; Matthews, Christine G.; Stacy, Kathryn

    1994-01-01

    THRTOOL program applies thresholding techniques to Sun rasterfiles. Provides for choice among four methods of thresholding. Written in C language and implemented on Sun series and Silicon Graphics IRIS machines.

  20. USE OF THRESHOLDS IN LANDSCAPE ASSESSMENTS

    EPA Science Inventory

    Identification and use of thresholds are potentially important additions to interpretations of ecological monitoring data. However, there are a number of issues related to defining and using thresholds in interpreting ecological data. Most of these issues center around the pauc...

  1. Thresholds for impaired species recovery.

    PubMed

    Hutchings, Jeffrey A

    2015-06-22

    Studies on small and declining populations dominate research in conservation biology. This emphasis reflects two overarching frameworks: the small-population paradigm focuses on correlates of increased extinction probability; the declining-population paradigm directs attention to the causes and consequences of depletion. Neither, however, particularly informs research on the determinants, rate or uncertainty of population increase. By contrast, Allee effects (positive associations between population size and realized per capita population growth rate, r(realized), a metric of average individual fitness) offer a theoretical and empirical basis for identifying numerical and temporal thresholds at which recovery is unlikely or uncertain. Following a critique of studies on Allee effects, I quantify population-size minima and subsequent trajectories of marine fishes that have and have not recovered following threat mitigation. The data suggest that threat amelioration, albeit necessary, can be insufficient to effect recovery for populations depleted to less than 10% of maximum abundance (N(max)), especially when they remain depleted for lengthy periods of time. Comparing terrestrial and aquatic vertebrates, life-history analyses suggest that population-size thresholds for impaired recovery are likely to be comparatively low for marine fishes but high for marine mammals.Articulation of a 'recovering population paradigm' would seem warranted. It might stimulate concerted efforts to identify generic impaired recovery thresholds across species. It might also serve to reduce the confusion of terminology, and the conflation of causes and consequences with patterns currently evident in the literature on Allee effects, thus strengthening communication among researchers and enhancing the practical utility of recovery-oriented research to conservation practitioners and resource managers. PMID:26213739

  2. Thresholds for impaired species recovery

    PubMed Central

    Hutchings, Jeffrey A.

    2015-01-01

    Studies on small and declining populations dominate research in conservation biology. This emphasis reflects two overarching frameworks: the small-population paradigm focuses on correlates of increased extinction probability; the declining-population paradigm directs attention to the causes and consequences of depletion. Neither, however, particularly informs research on the determinants, rate or uncertainty of population increase. By contrast, Allee effects (positive associations between population size and realized per capita population growth rate, rrealized, a metric of average individual fitness) offer a theoretical and empirical basis for identifying numerical and temporal thresholds at which recovery is unlikely or uncertain. Following a critique of studies on Allee effects, I quantify population-size minima and subsequent trajectories of marine fishes that have and have not recovered following threat mitigation. The data suggest that threat amelioration, albeit necessary, can be insufficient to effect recovery for populations depleted to less than 10% of maximum abundance (Nmax), especially when they remain depleted for lengthy periods of time. Comparing terrestrial and aquatic vertebrates, life-history analyses suggest that population-size thresholds for impaired recovery are likely to be comparatively low for marine fishes but high for marine mammals. Articulation of a ‘recovering population paradigm’ would seem warranted. It might stimulate concerted efforts to identify generic impaired recovery thresholds across species. It might also serve to reduce the confusion of terminology, and the conflation of causes and consequences with patterns currently evident in the literature on Allee effects, thus strengthening communication among researchers and enhancing the practical utility of recovery-oriented research to conservation practitioners and resource managers. PMID:26213739

  3. Threshold Concepts in Finance: Student Perspectives

    ERIC Educational Resources Information Center

    Hoadley, Susan; Kyng, Tim; Tickle, Leonie; Wood, Leigh N.

    2015-01-01

    Finance threshold concepts are the essential conceptual knowledge that underpin well-developed financial capabilities and are central to the mastery of finance. In this paper we investigate threshold concepts in finance from the point of view of students, by establishing the extent to which students are aware of threshold concepts identified by…

  4. Compositional threshold for Nuclear Waste Glass Durability

    SciTech Connect

    Kruger, Albert A.; Farooqi, Rahmatullah; Hrma, Pavel R.

    2013-04-24

    Within the composition space of glasses, a distinct threshold appears to exist that separates "good" glasses, i.e., those which are sufficiently durable, from "bad" glasses of a low durability. The objective of our research is to clarify the origin of this threshold by exploring the relationship between glass composition, glass structure and chemical durability around the threshold region.

  5. On the threshold electric field for the @1-m auroral irregularity appearance

    SciTech Connect

    Kustov, A.; Uspensky, M. ); Kangas, J.; Huuskonen, A. ); Nielsen, E. )

    1989-09-01

    The authors study the electric field threshold for 1-m auroral electrojet irregularity excitation, using data from the special Finnish EISCAT experiment held on November 17, 1983. They found that at times irregularities can arise when the ionospheric electric field is 5-15 mV/m, i.e., well below the Farley-Buneman instability threshold. The electron density fluctuations derived here are increased when the E field becomes more than 15 mV/m. As a result the dependence of electron density fluctuation amplitude on electric fields has a kind of a soft E field threshold. Possible reasons for such a dependence are discussed. They show that unresolved ionospheric microstructure in the radar scattering volume can cause this threshold spreading.

  6. Thresholds, Mode-Switching, and Emergent Pseudo-Equilibrium in Geomorphic Systems

    NASA Astrophysics Data System (ADS)

    Phillips, J. D.

    2012-04-01

    Many geomorphic systems exhibit mode shifts as they evolve, or react to disturbances, from an initial mode of dynamically unstable, divergent evolution, to a mode of convergent evolution. These trends are often interpreted as progression toward a normative equilibrium. However, these mode shifts are shown to arise from two basic principles: gradient (or resistance) selection, and threshold-mediated modulation. In early stages of system development positive feedbacks associated with gradient selection are dominant, and dynamical instability, chaos, and divergence result. Eventually, however, as the system approaches limiting thresholds, negative feedback associated with the thresholds becomes stronger than the positive feedbacks, and the system becomes stable, with convergent evolution. The unstable-to-stable mode switches are an emergent outcome of the gradient selection and threshold modulation principles, not a goal function of Earth surface systems. These principles are illustrated with two examples—fluvial dissection of the Cumberland Plateau, Kentucky, and channel development in deltas of the Texas coastal plain.

  7. Monitoring cropping patterns using sequential Landsat imagery: An adaptive threshold approach and its application in Phoenix, AZ

    NASA Astrophysics Data System (ADS)

    Fan, C.; Zheng, B.; Myint, S. W.; Aggarwal, R.

    2014-12-01

    Cropping intensity is the number of crops grown per year per unit area of cropland. Since 1970s, the Phoenix Active Management Area (AMA) has undergone rapid urbanization mostly via land conversions from agricultural prime lands to urban land use. Agricultural intensification, or multiple cropping, has been observed globally as a positive response to the growing land pressure as a consequence of urbanization and exploding population. Nevertheless, increased cropping intensity has associated local, regional, and global environmental outcomes such as degradation of water quality and soil fertility. Quantifying spatio-temporal patterns of cropping intensity can serve as a first step towards understanding these environmental problems and developing effective and sustainable cropping strategies. In this study, an adaptive threshold method was developed to measure the cropping intensity in the Phoenix AMA from 1995 to 2010 at five-year intervals. The method has several advantages in terms of (1) minimization of errors arising from missing data and noise; (2) ability to distinguish growing cycles from multiple small false peaks in a vegetation index time series; (3) flexibility when dealing with temporal profiles with diffing numbers of observations. The adaptive threshold approach measures the cropping intensity effectively with overall accuracies higher than 97%. Results indicate a dramatic decline in the area of total croplands, single crops, and double crops. A small land conversion was witnessed from single crops into double crops from 1995 to 2000, whereas a reverse trend was observed from 2005 to 2010. Changes in cropping intensity can affect local water consumption. Therefore, joint investigation of cropping patterns and agricultural water use can provide implications for future water demand, which is an increasingly critical issue in this rapidly expanding desert city.

  8. Epidemic threshold in directed networks.

    PubMed

    Li, Cong; Wang, Huijuan; Van Mieghem, Piet

    2013-12-01

    Epidemics have so far been mostly studied in undirected networks. However, many real-world networks, such as the online social network Twitter and the world wide web, on which information, emotion, or malware spreads, are directed networks, composed of both unidirectional links and bidirectional links. We define the directionality ξ as the percentage of unidirectional links. The epidemic threshold τ(c) for the susceptible-infected-susceptible (SIS) epidemic is lower bounded by 1/λ(1) in directed networks, where λ(1), also called the spectral radius, is the largest eigenvalue of the adjacency matrix. In this work, we propose two algorithms to generate directed networks with a given directionality ξ. The effect of ξ on the spectral radius λ(1), principal eigenvector x(1), spectral gap (λ(1)-|λ(2)|), and algebraic connectivity μ(N-1) is studied. Important findings are that the spectral radius λ(1) decreases with the directionality ξ, whereas the spectral gap and the algebraic connectivity increase with the directionality ξ. The extent of the decrease of the spectral radius depends on both the degree distribution and the degree-degree correlation ρ(D). Hence, in directed networks, the epidemic threshold is larger and a random walk converges to its steady state faster than that in undirected networks with the same degree distribution. PMID:24483506

  9. Epidemic threshold in directed networks

    NASA Astrophysics Data System (ADS)

    Li, Cong; Wang, Huijuan; Van Mieghem, Piet

    2013-12-01

    Epidemics have so far been mostly studied in undirected networks. However, many real-world networks, such as the online social network Twitter and the world wide web, on which information, emotion, or malware spreads, are directed networks, composed of both unidirectional links and bidirectional links. We define the directionality ξ as the percentage of unidirectional links. The epidemic threshold τc for the susceptible-infected-susceptible (SIS) epidemic is lower bounded by 1/λ1 in directed networks, where λ1, also called the spectral radius, is the largest eigenvalue of the adjacency matrix. In this work, we propose two algorithms to generate directed networks with a given directionality ξ. The effect of ξ on the spectral radius λ1, principal eigenvector x1, spectral gap (λ1-λ2), and algebraic connectivity μN-1 is studied. Important findings are that the spectral radius λ1 decreases with the directionality ξ, whereas the spectral gap and the algebraic connectivity increase with the directionality ξ. The extent of the decrease of the spectral radius depends on both the degree distribution and the degree-degree correlation ρD. Hence, in directed networks, the epidemic threshold is larger and a random walk converges to its steady state faster than that in undirected networks with the same degree distribution.

  10. Computational gestalts and perception thresholds.

    PubMed

    Desolneux, Agnès; Moisan, Lionel; Morel, Jean-Michel

    2003-01-01

    In 1923, Max Wertheimer proposed a research programme and method in visual perception. He conjectured the existence of a small set of geometric grouping laws governing the perceptual synthesis of phenomenal objects, or "gestalt" from the atomic retina input. In this paper, we review this set of geometric grouping laws, using the works of Metzger, Kanizsa and their schools. In continuation, we explain why the Gestalt theory research programme can be translated into a Computer Vision programme. This translation is not straightforward, since Gestalt theory never addressed two fundamental matters: image sampling and image information measurements. Using these advances, we shall show that gestalt grouping laws can be translated into quantitative laws allowing the automatic computation of gestalts in digital images. From the psychophysical viewpoint, a main issue is raised: the computer vision gestalt detection methods deliver predictable perception thresholds. Thus, we are set in a position where we can build artificial images and check whether some kind of agreement can be found between the computationally predicted thresholds and the psychophysical ones. We describe and discuss two preliminary sets of experiments, where we compared the gestalt detection performance of several subjects with the predictable detection curve. In our opinion, the results of this experimental comparison support the idea of a much more systematic interaction between computational predictions in Computer Vision and psychophysical experiments. PMID:14766147

  11. Contraction Options and Optimal Multiple-Stopping in Spectrally Negative Lévy Models

    SciTech Connect

    Yamazaki, Kazutoshi

    2015-08-15

    This paper studies the optimal multiple-stopping problem arising in the context of the timing option to withdraw from a project in stages. The profits are driven by a general spectrally negative Lévy process. This allows the model to incorporate sudden declines of the project values, generalizing greatly the classical geometric Brownian motion model. We solve the one-stage case as well as the extension to the multiple-stage case. The optimal stopping times are of threshold-type and the value function admits an expression in terms of the scale function. A series of numerical experiments are conducted to verify the optimality and to evaluate the efficiency of the algorithm.

  12. Fluctuation scaling in the visual cortex at threshold

    NASA Astrophysics Data System (ADS)

    Medina, José M.; Díaz, José A.

    2016-05-01

    Fluctuation scaling relates trial-to-trial variability to the average response by a power function in many physical processes. Here we address whether fluctuation scaling holds in sensory psychophysics and its functional role in visual processing. We report experimental evidence of fluctuation scaling in human color vision and form perception at threshold. Subjects detected thresholds in a psychophysical masking experiment that is considered a standard reference for studying suppression between neurons in the visual cortex. For all subjects, the analysis of threshold variability that results from the masking task indicates that fluctuation scaling is a global property that modulates detection thresholds with a scaling exponent that departs from 2, β =2.48 ±0.07 . We also examine a generalized version of fluctuation scaling between the sample kurtosis K and the sample skewness S of threshold distributions. We find that K and S are related and follow a unique quadratic form K =(1.19 ±0.04 ) S2+(2.68 ±0.06 ) that departs from the expected 4/3 power function regime. A random multiplicative process with weak additive noise is proposed based on a Langevin-type equation. The multiplicative process provides a unifying description of fluctuation scaling and the quadratic S -K relation and is related to on-off intermittency in sensory perception. Our findings provide an insight into how the human visual system interacts with the external environment. The theoretical methods open perspectives for investigating fluctuation scaling and intermittency effects in a wide variety of natural, economic, and cognitive phenomena.

  13. A Rare Nasopharyngeal Teratoma Arising From the Vomer.

    PubMed

    Pang, Xiaoxiao; Kwon, Hyuk-Jae; Shi, Bing; Li, Chenghao

    2016-03-01

    Teratomas are rare germ cell neoplasms derived from the 3 germinal layers (ectoderm, mesoderm, and endoderm). Nasopharyngeal teratoma is a very rare teratoma arising anywhere from the oronasal cavity, regarded as an expanding, avity filling lesion, with a high mortality rate because of severe airway obstruction, especially in the neonatal period and make up only 2% of all teratomas. The authors present a case of an infant girl with a single, finger-like, hairy teratoma arising from the vomer and protruding from the mouth with bilateral complete cleft palate, cleft lip, and cleft alveolus. Complete intraoral resection of the teratoma and cleft lip repair was conducted simultaneously. Reconstruction of the cleft palate was performed at a later stage. Recurrence occurred 9 months after surgery and extended complete surgical excision was performed after recurrence, with no recurrence observed again to date. Histopathologic examination confirmed the diagnosis of congenital mature teratoma. PMID:26854776

  14. Invasive breast carcinoma arising in microglandular adenosis: two case reports.

    PubMed

    Choi, Jung Eun; Bae, Young Kyung

    2013-12-01

    Microglandular adenosis (MGA) is a rare benign disease that shows an infiltrative growth pattern of small glands, and it may progress to include atypia and carcinoma. Here we report two cases of breast carcinoma arising in MGA. Case 1 was a 44-year-old woman with a previous history of ductal carcinoma in situ in her right breast. During a follow-up, a 1.8 cm mass-like lesion was found in her left breast. An excisional biopsy suggested that the lesion was breast carcinoma. Case 2 was a 57-year-old woman with a 2.9 cm mass in her right breast. A core needle biopsy of the lesion suggested invasive carcinoma. Both patients underwent modified radical mastectomy with sentinel lymph node biopsy. Both tumors lacked a myoepithelial cell layer and stained positively for S-100, lysozyme, and α1-antitrypsin, which is typical of MGA. Both cases showed invasive carcinoma arising in MGA. PMID:24454466

  15. Bend stresses arising from ion-exchange diffusion in glasses

    SciTech Connect

    Babukova, M.V.; Glebov, L.B.; Nikonorov, N.V.; Petrovskii, G.T.

    1985-11-01

    This paper demonstrates experimental confirmation of the presence of gigastresses arising under ion exchange, for the purpose of providing data relating to the magnitudes of stress greater than 1 GPa in these ion-exchange layers. To determine the stresses, a bend method was used on a specimen under nonuniform load. Small values of bend were determined on an IT-70 inferometer. With larger values of bend the radius of curvature of the surface was determined by measuring the focal distance in the beam of a He-Ne laser reflected from the specimen. Bending is observed in silicate glass subjected to unilateral ion-exchange diffusion of K/sup +/. It is shown that the bending of the specimens is caused by compressive stresses arising in the diffusion layer and having a value of greater than 1.5 GPa. The changes in the refractive index (RI) in the diffusion layer are determined primarily by the photoelastic effect.

  16. [A solitary neurofibroma arising from the temporal fossa].

    PubMed

    Tian, Xiaoyan; Luo, Gui; Zhu, Xinhua

    2014-07-01

    Neurofibromas are benign nerve sheath tumors that arise from the nonmyelinating Schwann cells. Generally, neurofibromas can be categorized into dermal and plexiform subtypes. The former subtype is usually associated with a lone peripheral nerve in the integumentary system, while plexiform tumors are associated with many nerve bundles and can originate internally. Rarely, the plexiform tumors can undergo malignant transformation. Neurofibromas are usually found in individuals with neurofibromatosis, which is an autosomal dominant disease. On occasion, an isolated neurofibroma can transpire without being associated with neurofibromatosis. Mostly, these solitary tumors tend to occur in the gastrointestinal system, and neurofibromas of the head and neck are not uncommon, but very rarely they have been reported to occur in the temporal fossa. In this report, we describe a case of a solitary neurofibroma arising from the temporal fossa. PMID:25248275

  17. Angiosarcoma arising in an ovarian fibroma: a case report.

    PubMed

    Cambruzzi, Eduardo; Pegas, Karla Lais; Milani, Daniel Marini; Cruz, Ricardo Pedrini; Guerra, Enilde Heloena; Ferrari, Márcio Balbinotti

    2010-01-01

    Primary ovarian angiosarcoma is a very rare gynaecological sarcoma, with poor prognosis. These tumors are though to arise from carcinosarcomas, teratomas, or the ovarian vasculature and occur at any age. There are only a few cases reported in the international literature, most commonly associated to surface epithelial-stromal or germ cell tumours. Herein, the authors report the clinicopathologic features of an angiosarcoma arising in an ovarian fibroma. A 65-year-old patient was admitted with a palpable mass in the hypogastrium. Grossly, the removed ovary was completely replaced by a solid tumor mass. On histological analysis, the lesion revealed the typical histological features of angiosarcoma with sinusoidal patterns and anaplastic cells, admixed with spindle-shaped cells arranged in fascicles or in a storiform pattern, compatible with a fibroma. The vascular component was strongly immunopositive for CD31 and CD34. The patient was submitted to chemotherapy, and she was alive for two months after surgical proceedings. PMID:21151524

  18. Myofibroblastoma arising in mammary hamartoma: a case report.

    PubMed

    Uchôa, Diego M; Cruz, Dênnis Baroni; Schaefer, Pedro Guilherme; Pêgas, Karla Laís; Cambruzzi, Eduardo

    2010-01-01

    Myofibroblastoma (MFB) is a rare mesenchymal tumor arising in breast's soft tissue with a great variety of microscopic features that can be mistaken with a wide variety of biphasic lesions. The authors report a rare case of myofibroblastoma of the breast arising in a mammary hamartoma (MH), present a review of the clinicopathological features of these lesions, and make some diagnostic considerations. The tumour consisted of a well-circumscribed nodule. MFB component comprised about fifty percent of the lesion and was made up of bipolar spindle cells arranged in fascicular clusters separated by bands of hyalinized collagen. There were fat cells and several residual hamartoma glands intermingled and distorted in MFB area. MFB component was positive for Desmin, CD34, bcl-2, and Calponin. To the best of our knowledge, MFB has not been reported in MH, neither has any of the reports described mammary glands joined within MFB. PMID:21151720

  19. Acute Lymphoblastic Leukemia Arising in CALR Mutated Essential Thrombocythemia

    PubMed Central

    Langabeer, Stephen E.; Haslam, Karl; O'Brien, David; Kelly, Johanna; Andrews, Claire; Ryan, Ciara; Flavin, Richard; Hayden, Patrick J.; Bacon, Christopher L.

    2016-01-01

    The development of acute lymphoblastic leukemia in an existing myeloproliferative neoplasm is rare with historical cases unable to differentiate between concomitant malignancies or leukemic transformation. Molecular studies of coexisting JAK2 V617F-positive myeloproliferative neoplasms and mature B cell malignancies indicate distinct disease entities arising in myeloid and lymphoid committed hematopoietic progenitor cells, respectively. Mutations of CALR in essential thrombocythemia appear to be associated with a distinct phenotype and a lower risk of thrombosis yet their impact on disease progression is less well defined. The as yet undescribed scenario of pro-B cell acute lymphoblastic leukemia arising in CALR mutated essential thrombocythemia is presented. Intensive treatment for the leukemia allowed for expansion of the original CALR mutated clone. Whether CALR mutations in myeloproliferative neoplasms predispose to the acquisition of additional malignancies, particularly lymphoproliferative disorders, is not yet known. PMID:26904322

  20. Threshold selection for classification of MR brain images by clustering method

    SciTech Connect

    Moldovanu, Simona; Obreja, Cristian; Moraru, Luminita

    2015-12-07

    Given a grey-intensity image, our method detects the optimal threshold for a suitable binarization of MR brain images. In MR brain image processing, the grey levels of pixels belonging to the object are not substantially different from the grey levels belonging to the background. Threshold optimization is an effective tool to separate objects from the background and further, in classification applications. This paper gives a detailed investigation on the selection of thresholds. Our method does not use the well-known method for binarization. Instead, we perform a simple threshold optimization which, in turn, will allow the best classification of the analyzed images into healthy and multiple sclerosis disease. The dissimilarity (or the distance between classes) has been established using the clustering method based on dendrograms. We tested our method using two classes of images: the first consists of 20 T2-weighted and 20 proton density PD-weighted scans from two healthy subjects and from two patients with multiple sclerosis. For each image and for each threshold, the number of the white pixels (or the area of white objects in binary image) has been determined. These pixel numbers represent the objects in clustering operation. The following optimum threshold values are obtained, T = 80 for PD images and T = 30 for T2w images. Each mentioned threshold separate clearly the clusters that belonging of the studied groups, healthy patient and multiple sclerosis disease.

  1. Threshold selection for classification of MR brain images by clustering method

    NASA Astrophysics Data System (ADS)

    Moldovanu, Simona; Obreja, Cristian; Moraru, Luminita

    2015-12-01

    Given a grey-intensity image, our method detects the optimal threshold for a suitable binarization of MR brain images. In MR brain image processing, the grey levels of pixels belonging to the object are not substantially different from the grey levels belonging to the background. Threshold optimization is an effective tool to separate objects from the background and further, in classification applications. This paper gives a detailed investigation on the selection of thresholds. Our method does not use the well-known method for binarization. Instead, we perform a simple threshold optimization which, in turn, will allow the best classification of the analyzed images into healthy and multiple sclerosis disease. The dissimilarity (or the distance between classes) has been established using the clustering method based on dendrograms. We tested our method using two classes of images: the first consists of 20 T2-weighted and 20 proton density PD-weighted scans from two healthy subjects and from two patients with multiple sclerosis. For each image and for each threshold, the number of the white pixels (or the area of white objects in binary image) has been determined. These pixel numbers represent the objects in clustering operation. The following optimum threshold values are obtained, T = 80 for PD images and T = 30 for T2w images. Each mentioned threshold separate clearly the clusters that belonging of the studied groups, healthy patient and multiple sclerosis disease.

  2. The pathophysiology of medication errors: how and where they arise

    PubMed Central

    McDowell, Sarah E; Ferner, Harriet S; Ferner, Robin E

    2009-01-01

    Errors arise when an action is intended but not performed; errors that arise from poor planning or inadequate knowledge are characterized as mistakes; those that arise from imperfect execution of well-formulated plans are called slips when an erroneous act is committed and lapses when a correct act is omitted. Some tasks are intrinsically prone to error. Examples are tasks that are unfamiliar to the operator or performed under pressure. Tasks that require the calculation of a dosage or dilution are especially susceptible to error. The tasks of prescribing, preparation, and administration of medicines are complex, and are carried out within a complex system; errors can occur at each of many steps and the error rate for the overall process is therefore high. The error rate increases when health-care professionals are inexperienced, inattentive, rushed, distracted, fatigued, or depressed; orthopaedic surgeons and nurses may be more likely than other health-care professionals to make medication errors. Medication error rates in hospital are higher in paediatric departments and intensive care units than elsewhere. Rates of medication errors may be higher in very young or very old patients. Intravenous antibiotics are the drugs most commonly involved in medication errors in hospital; antiplatelet agents, diuretics, and non-steroidal anti-inflammatory drugs are most likely to account for ‘preventable admissions’. Computers effectively reduce the rates of easily counted errors. It is not clear whether they can save lives lost through rare but dangerous errors in the medication process. PMID:19594527

  3. Input-output relation and energy efficiency in the neuron with different spike threshold dynamics

    PubMed Central

    Yi, Guo-Sheng; Wang, Jiang; Tsang, Kai-Ming; Wei, Xi-Le; Deng, Bin

    2015-01-01

    Neuron encodes and transmits information through generating sequences of output spikes, which is a high energy-consuming process. The spike is initiated when membrane depolarization reaches a threshold voltage. In many neurons, threshold is dynamic and depends on the rate of membrane depolarization (dV/dt) preceding a spike. Identifying the metabolic energy involved in neural coding and their relationship to threshold dynamic is critical to understanding neuronal function and evolution. Here, we use a modified Morris-Lecar model to investigate neuronal input-output property and energy efficiency associated with different spike threshold dynamics. We find that the neurons with dynamic threshold sensitive to dV/dt generate discontinuous frequency-current curve and type II phase response curve (PRC) through Hopf bifurcation, and weak noise could prohibit spiking when bifurcation just occurs. The threshold that is insensitive to dV/dt, instead, results in a continuous frequency-current curve, a type I PRC and a saddle-node on invariant circle bifurcation, and simultaneously weak noise cannot inhibit spiking. It is also shown that the bifurcation, frequency-current curve and PRC type associated with different threshold dynamics arise from the distinct subthreshold interactions of membrane currents. Further, we observe that the energy consumption of the neuron is related to its firing characteristics. The depolarization of spike threshold improves neuronal energy efficiency by reducing the overlap of Na+ and K+ currents during an action potential. The high energy efficiency is achieved at more depolarized spike threshold and high stimulus current. These results provide a fundamental biophysical connection that links spike threshold dynamics, input-output relation, energetics and spike initiation, which could contribute to uncover neural encoding mechanism. PMID:26074810

  4. Rejection Thresholds in Chocolate Milk: Evidence for Segmentation

    PubMed Central

    Harwood, Meriel L.; Ziegler, Gregory R.; Hayes, John E.

    2012-01-01

    Bitterness is generally considered a negative attribute in food, yet many individuals enjoy some bitterness in products like coffee or chocolate. In chocolate, bitterness arises from naturally occurring alkaloids and phenolics found in cacao. Fermentation and roasting help develop typical chocolate flavor and reduce the intense bitterness of raw cacao by modifying these bitter compounds. As it becomes increasingly common to fortify chocolate with `raw' cacao to increase the amount of healthful phytonutrients, it is important to identify the point at which the concentration of bitter compounds becomes objectionable, even to those who enjoy some bitterness. Classical threshold methods focus on the presence or absence of a sensation rather than acceptability or hedonics. A new alternative, the rejection threshold, was recently described in the literature. Here, we sought to quantify and compare differences in Rejection Thresholds (RjT) and Detection Thresholds (DT) in chocolate milk spiked with a food safe bitterant (sucrose octaacetate). In experiment 1, a series of paired preference tests was used to estimate the RjT for bitterness in chocolate milk. In a new group of participants (experiment 2), we determined the RjT and DT using the forced choice ascending method of limits. In both studies, participants were segmented on the basis of self-declared preference for milk or dark solid chocolate. Based on sigmoid fits of the indifference-preference function, the RjT was ~2.3 times higher for those preferring dark chocolate than the RjT for those preferring milk chocolate in both experiments. In contrast, the DT for both groups was functionally identical, suggesting that differential effects of bitterness on liking of chocolate products are not based on the ability to detect bitterness in these products. PMID:22754143

  5. Threshold Phenomena in Atomic Inner Shells

    NASA Astrophysics Data System (ADS)

    Wang, Honghong

    1995-01-01

    Two types of atomic inner-shell threshold phenomena are studied: (1) atomic inner-shell radiationless resonant Raman scattering (RRRS) as a function of excitation energy, and (2) the onset of Cu Coster-Kronig (CK) transitions due to extraatomic relaxation, as a function of cluster size. (1). The K-L_{2,3}L _{2,3} and L_{2,3 }-VV Auger spectra of P in InP were measured in the vicinity of the P K-shell ionization threshold as well as at high excess energies. The evolution of the P K-L_{2,3 }L_{2,3} ^1D Auger spectrum from the radiationless resonant Raman scattering regime into the normal Auger transition regime in InP is found to be in accordance with time-independent resonant scattering theory of inner-shell threshold phenomena. The measured RRRS intensity reveals a quasi-bound state in the bulk-sensitive P K absorption spectrum. The origins of deviations of the RRRS energy from linear dispersion are examined in terms of the finite incident-photon-energy distribution and multiple resonances. Both our measurements and semiclassical calculations show that the post-collision interaction effect is relatively small. The measured P K-L_{2,3}L_{2,3} intensities and P 1s lifetime width are found to be in good agreement with atomic calculations, revealing the predominantly atomic character of P inner-shell transitions in InP. The evolution of P L_{2,3 }-VV Auger transitions in InP is found to be sensitive to the excitation energy at the P 1s threshold; the P K-L_{2,3}L_{2,3 } Raman resonance causes changes in the L _{2,3}-VV diagram-transition line shape as well as intensity enhancement of all L _{2,3}-VV features. Applying the Cini-Sawatzky model to the line shape reveals a 0.3-eV change in the local effective Coulomb interaction U _{eff} near the resonance. The difference in the line shapes between the satellite and diagram transitions indicates a change of the local density of states in the valence band in the presence of a spectator 2p hole. The single- and double-2p

  6. Embracing thresholds for better environmental management

    PubMed Central

    Kelly, Ryan P.; Erickson, Ashley L.; Mease, Lindley A.; Battista, Willow; Kittinger, John N.; Fujita, Rod

    2015-01-01

    Three decades of study have revealed dozens of examples in which natural systems have crossed biophysical thresholds (‘tipping points’)—nonlinear changes in ecosystem structure and function—as a result of human-induced stressors, dramatically altering ecosystem function and services. Environmental management that avoids such thresholds could prevent severe social, economic and environmental impacts. Here, we review management measures implemented in ecological systems that have thresholds. Using Ostrom's social–ecological systems framework, we analysed key biophysical and institutional factors associated with 51 social–ecological systems and associated management regimes, and related these to management success defined by ecological outcomes. We categorized cases as instances of prospective or retrospective management, based upon whether management aimed to avoid a threshold or to restore systems that have crossed a threshold. We find that smaller systems are more amenable to threshold-based management, that routine monitoring is associated with successful avoidance of thresholds and recovery after thresholds have been crossed, and that success is associated with the explicit threshold-based management. These findings are powerful evidence for the policy relevance of information on ecological thresholds across a wide range of ecosystems.

  7. Whole-body vibration perception thresholds

    NASA Astrophysics Data System (ADS)

    Parsons, K. C.; Griffin, M. J.

    1988-03-01

    This paper presents the results of a series of laboratory experiments concerned with perception thresholds for whole-body vibration. The nature of absolute perception thresholds is discussed and a method of determining vibration thresholds, based upon signal detection theory, is proposed. Thresholds of subjects exposed to x-, y- and z-axis sinusoidal vibration were determined for sitting and standing subjects (from 2 to 100 Hz). Perception thresholds have also been determined for supine subjects exposed to vertical ( x-axis) sinusoidal vibration (10-63 Hz). In additional experiments the effects of complex (e.g., random) vibration and the effects of duration on the perception thresholds were investigated. The relation between perception thresholds and vibration levels, said by subjects to be unacceptable if they occurred in their own homes, was investigated as well as the effects of subjects' personality and the visual and acoustic conditions in the laboratory. For the vertical vibration of seated subjects no significant differences were found between the responses of male and female subjects. Significant differences were found between perception thresholds for sitting and standing postures. The median threshold was approximately 0·01 m/s 2 r.m.s. between 2 and 100 Hz. Perception thresholds for x-axis and y-axis vibration were not significantly different in either sitting or standing subjects but significant differences in thresholds were found between sitting and standing positions for both x-axis and y-axis vibration. Subjects tended to be more sensitive to vibration when lying than when sitting or standing. The results suggested that the perception of random vibrations can be predicted from a knowledge of the perception of its component vibrations. The number of cycles of vibration did not affect perception thresholds for vibration durations of more than about 0·25 s. Some assessments suggested that vibration at more than twice the perception threshold may not

  8. How insurance affects altruistic provision in threshold public goods games

    PubMed Central

    Zhang, Jianlei; Zhang, Chunyan; Cao, Ming

    2015-01-01

    The occurrence and maintenance of cooperative behaviors in public goods systems have attracted great research attention across multiple disciplines. A threshold public goods game requires a minimum amount of contributions to be collected from a group of individuals for provision to occur. Here we extend the common binary-strategy combination of cooperation and defection by adding a third strategy, called insured cooperation, which corresponds to buying an insurance covering the potential loss resulted from the unsuccessful public goods game. Particularly, only the contributing agents can opt to be insured, which is an effort decreasing the amount of the potential loss occurring. Theoretical computations suggest that when agents face the potential aggregate risk in threshold public goods games, more contributions occur with increasing compensation from insurance. Moreover, permitting the adoption of insurance significantly enhances individual contributions and facilitates provision, especially when the required threshold is high. This work also relates the strategy competition outcomes to different allocation rules once the resulted contributions exceed the threshold point in populations nested within a dilemma. PMID:25765206

  9. Optimal Selection of Threshold Value 'r' for Refined Multiscale Entropy.

    PubMed

    Marwaha, Puneeta; Sunkaria, Ramesh Kumar

    2015-12-01

    Refined multiscale entropy (RMSE) technique was introduced to evaluate complexity of a time series over multiple scale factors 't'. Here threshold value 'r' is updated as 0.15 times SD of filtered scaled time series. The use of fixed threshold value 'r' in RMSE sometimes assigns very close resembling entropy values to certain time series at certain temporal scale factors and is unable to distinguish different time series optimally. The present study aims to evaluate RMSE technique by varying threshold value 'r' from 0.05 to 0.25 times SD of filtered scaled time series and finding optimal 'r' values for each scale factor at which different time series can be distinguished more effectively. The proposed RMSE was used to evaluate over HRV time series of normal sinus rhythm subjects, patients suffering from sudden cardiac death, congestive heart failure, healthy adult male, healthy adult female and mid-aged female groups as well as over synthetic simulated database for different datalengths 'N' of 3000, 3500 and 4000. The proposed RMSE results in improved discrimination among different time series. To enhance the computational capability, empirical mathematical equations have been formulated for optimal selection of threshold values 'r' as a function of SD of filtered scaled time series and datalength 'N' for each scale factor 't'. PMID:26577486

  10. Symmetric Lipomatosis Arising in the Tongue Presenting as Macroglossia and Articulatory Disorder

    PubMed Central

    Omura, Ken; Satsukawa, Arata; Taguchi, Takahide; Harada, Hiroyuki; Ishii, Yoshimasa

    2016-01-01

    Symmetric lipomatosis is definitively characterized by symmetric, tumorous lipomatous proliferation of adipose tissue that often develops in the head and neck, shoulders, and upper trunk. However, in the oral region, symmetric lipomatosis of the tongue (SLT) is an extremely rare condition related to generalized lipidosis that is often caused by chronic alcoholism. It is characterized by multiple symmetric lipomatous nodules and diffuse bilateral swelling located within the tongue. We report an extremely rare case of SLT arising in an 80-year-old man with a long history of alcoholic liver cirrhosis. He exhibited multiple soft nodular protrusions on the bilateral margin of the tongue presenting as macroglossia for years. Although MR imaging showed multiple fatty masses on both sides of the tongue, there was no elevated tumor mass on the bilateral margin. The patient underwent bilateral partial glossectomy under general anesthesia. Histopathologically, the resected tumor exhibited diffuse infiltration with mature adipose tissue lacking a fibrous capsule. Due to the lipidosis and the unusual presentation of multiple lesions, the lesion was ultimately diagnosed as SLT. At present, after surgery, the patient wears a full-denture and is in excellent condition, with no sign of recurrence, improved QOL, and recovery of masticatory, articulatory, and speech intelligibility functions. PMID:27413566

  11. Genetics Home Reference: multiple familial trichoepithelioma

    MedlinePlus

    ... with the skin (skin appendages), such as hair follicles and sweat glands. People with multiple familial trichoepithelioma ... round tumors called trichoepitheliomas, which arise from hair follicles. Trichoepitheliomas are generally noncancerous (benign) but occasionally develop ...

  12. Thresholds for Cenozoic bipolar glaciation.

    PubMed

    Deconto, Robert M; Pollard, David; Wilson, Paul A; Pälike, Heiko; Lear, Caroline H; Pagani, Mark

    2008-10-01

    The long-standing view of Earth's Cenozoic glacial history calls for the first continental-scale glaciation of Antarctica in the earliest Oligocene epoch ( approximately 33.6 million years ago), followed by the onset of northern-hemispheric glacial cycles in the late Pliocene epoch, about 31 million years later. The pivotal early Oligocene event is characterized by a rapid shift of 1.5 parts per thousand in deep-sea benthic oxygen-isotope values (Oi-1) within a few hundred thousand years, reflecting a combination of terrestrial ice growth and deep-sea cooling. The apparent absence of contemporaneous cooling in deep-sea Mg/Ca records, however, has been argued to reflect the growth of more ice than can be accommodated on Antarctica; this, combined with new evidence of continental cooling and ice-rafted debris in the Northern Hemisphere during this period, raises the possibility that Oi-1 represents a precursory bipolar glaciation. Here we test this hypothesis using an isotope-capable global climate/ice-sheet model that accommodates both the long-term decline of Cenozoic atmospheric CO(2) levels and the effects of orbital forcing. We show that the CO(2) threshold below which glaciation occurs in the Northern Hemisphere ( approximately 280 p.p.m.v.) is much lower than that for Antarctica ( approximately 750 p.p.m.v.). Therefore, the growth of ice sheets in the Northern Hemisphere immediately following Antarctic glaciation would have required rapid CO(2) drawdown within the Oi-1 timeframe, to levels lower than those estimated by geochemical proxies and carbon-cycle models. Instead of bipolar glaciation, we find that Oi-1 is best explained by Antarctic glaciation alone, combined with deep-sea cooling of up to 4 degrees C and Antarctic ice that is less isotopically depleted (-30 to -35 per thousand) than previously suggested. Proxy CO(2) estimates remain above our model's northern-hemispheric glaciation threshold of approximately 280 p.p.m.v. until approximately 25 Myr

  13. Parabolic Perturbation of a Nonlinear Hyperbolic Problem Arising in Physiology

    NASA Astrophysics Data System (ADS)

    Colli, P.; Grasselli, M.

    We study a transport-diffusion initial value problem where the diffusion codlicient is "small" and the transport coefficient is a time function depending on the solution in a nonlinear and nonlocal way. We show the existence and the uniqueness of a weak solution of this problem. Moreover we discuss its asymptotic behaviour as the diffusion coefficient goes to zero, obtaining a well-posed first-order nonlinear hyperbolic problem. These problems arise from mathematical models of muscle contraction in the framework of the sliding filament theory.

  14. Preconditioning a product of matrices arising in trust region subproblems

    SciTech Connect

    Hribar, M.E.; Plantenga, T.D.

    1996-03-01

    In solving large scale optimization problems, we find it advantageous to use iterative methods to solve the sparse linear systems that arise. In the ETR software for solving equality constrained optimization problems, we use a conjugate gradient method to approximately solve the trust region subproblems. To speed up the convergence of the conjugate gradient routine, we need to precondition matrices of the form Z{sup T} W Z, which are not explicitly stored. Four preconditioners were implemented and the results for each are given.

  15. Renal cell carcinoma arising in a regressed multicystic dysplastic kidney.

    PubMed

    Rackley, R R; Angermeier, K W; Levin, H; Pontes, J E; Kay, R

    1994-11-01

    Controversy surrounds the management of multicystic dysplastic kidney. Recent advances in radiological imaging have resulted in a higher incidence of its detection, and they provide an accurate noninvasive means of diagnosis and followup. Consequently, the need for surgical removal of these lesions is being reevaluated. We report a case of renal cell carcinoma arising from solid renal dysplasia associated with a regressed multicystic dysplastic kidney. We emphasize the potential risk of nonoperative management of these lesions and further define the spectrum of malignant degeneration associated with renal dysplasia. PMID:7933196

  16. Renal cell carcinoma arising in ipsilateral duplex system.

    PubMed

    Mohan, Harsh; Kundu, Reetu; Dalal, Usha

    2014-09-01

    Congenital anomalies of the kidney and urinary tract are common and include a wide anatomic spectrum. Duplex systems are one of the more common renal anomalies, with the majority being asymptomatic. Little is known about the molecular pathogenesis of these anomalies; however, certain causative genes have been implicated. The finding of renal cell carcinoma arising in a kidney with the duplication of pelvicalyceal system and ureters, as in the present case, is uncommon. The association between a duplex system and renal cell carcinoma may be more than a coincidence, requiring a deeper insight and further elucidation. PMID:26328175

  17. A method for detection of foreign body in cotton based on threshold segment

    NASA Astrophysics Data System (ADS)

    Sha, Tao; Xie, Tingting; Wang, Mengxue; Yang, Chaoyu

    2013-10-01

    In order to extract foreign body from the complex channel background and cotton layers, a detection method which combined improved Otsu threshold with background estimation threshold is presented. Firstly, the original image which containing multiple foreign fibers is divided into two new images which containing only two substances by Otsu threshold. And then using the estimated value of the means and the standard deviations of the two new images a background estimation threshold was determined. The foreign fibers are extracted by the estimation threshold. Simulation results show that this method can overcome the effect which caused by the channel background interference and diversity of the foreign fibers in the actual working environment and can extract foreign bodies quickly and effectively.

  18. The three thresholds for fatigue crack propagation

    SciTech Connect

    Miller, K.J.

    1997-12-01

    The three governing threshold conditions in metal fatigue are considered, one relating to crack growth in single crystals, one concerned with crack growth in polycrystalline materials, and one based on linear elastic fracture mechanics (LEFM). All three conditions are examined in relation to the two physical processes of cracking, i.e., Stage I (shear) and Stage II (tensile) crack growth. The LEFM threshold is seen as a lower bound condition for fatigue crack growth rate, and the single crystal threshold is viewed in relation to the fundamental threshold pertaining to the fatigue resistance of polycrystalline metals.

  19. A study of FM threshold extension techniques

    NASA Technical Reports Server (NTRS)

    Arndt, G. D.; Loch, F. J.

    1972-01-01

    The characteristics of three postdetection threshold extension techniques are evaluated with respect to the ability of such techniques to improve the performance of a phase lock loop demodulator. These techniques include impulse-noise elimination, signal correlation for the detection of impulse noise, and delta modulation signal processing. Experimental results from signal to noise ratio data and bit error rate data indicate that a 2- to 3-decibel threshold extension is readily achievable by using the various techniques. This threshold improvement is in addition to the threshold extension that is usually achieved through the use of a phase lock loop demodulator.

  20. Roots at the percolation threshold

    NASA Astrophysics Data System (ADS)

    Kroener, Eva; Ahmed, Mutez Ali; Carminati, Andrea

    2015-04-01

    The rhizosphere is the layer of soil around the roots where complex and dynamic interactions between plants and soil affect the capacity of plants to take up water. The physical properties of the rhizosphere are affected by mucilage, a gel exuded by roots. Mucilage can absorb large volumes of water, but it becomes hydrophobic after drying. We use a percolation model to describe the rewetting of dry rhizosphere. We find that at a critical mucilage concentration the rhizosphere becomes impermeable. The critical mucilage concentration depends on the radius of the soil particle size. Capillary rise experiments with neutron radiography prove that for concentrations below the critical mucilage concentration water could easily cross the rhizosphere, while above the critical concentration water could no longer percolate through it. Our studies, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water?

  1. Percolation Threshold in Polycarbonate Nanocomposites

    NASA Astrophysics Data System (ADS)

    Ahuja, Suresh

    2014-03-01

    Nanocomposites have unique mechanical, electrical, magnetic, optical and thermal properties. Many methods could be applied to prepare polymer-inorganic nanocomposites, such as sol-gel processing, in-situ polymerization, particle in-situ formation, blending, and radiation synthesis. The analytical composite models that have been put forth include Voigt and Reuss bounds, Polymer nanocomposites offer the possibility of substantial improvements in material properties such as shear and bulk modulus, yield strength, toughness, film scratch resistance, optical properties, electrical conductivity, gas and solvent transport, with only very small amounts of nanoparticles Experimental results are compared against composite models of Hashin and Shtrikman bounds, Halpin-Tsai model, Cox model, and various Mori and Tanaka models. Examples of numerical modeling are molecular dynamics modeling and finite element modeling of reduced modulus and hardness that takes into account the modulus of the components and the effect of the interface between the hard filler and relatively soft polymer, polycarbonate. Higher nanoparticle concentration results in poor dispersion and adhesion to polymer matrix which results in lower modulus and hardness and departure from the existing composite models. As the level of silica increases beyond a threshold level, aggregates form which results in weakening of the structure. Polymer silica interface is found to be weak as silica is non-interacting promoting interfacial slip at silica-matrix junctions. Our experimental results compare favorably with those of nanocomposites of polyesters where the effect of nanoclay on composite hardness and modulus depended on dispersion of nanoclay in polyester.

  2. Roots at the percolation threshold.

    PubMed

    Kroener, Eva; Ahmed, Mutez Ali; Carminati, Andrea

    2015-04-01

    The rhizosphere is the layer of soil around the roots where complex and dynamic interactions between plants and soil affect the capacity of plants to take up water. The physical properties of the rhizosphere are affected by mucilage, a gel exuded by roots. Mucilage can absorb large volumes of water, but it becomes hydrophobic after drying. We use a percolation model to describe the rewetting of dry rhizosphere. We find that at a critical mucilage concentration the rhizosphere becomes impermeable. The critical mucilage concentration depends on the radius of the soil particle size. Capillary rise experiments with neutron radiography prove that for concentrations below the critical mucilage concentration water could easily cross the rhizosphere, while above the critical concentration water could no longer percolate through it. Our studies, together with former observations of water dynamics in the rhizosphere, suggest that the rhizosphere is near the percolation threshold, where small variations in mucilage concentration sensitively alter the soil hydraulic conductivity. Is mucilage exudation a plant mechanism to efficiently control the rhizosphere conductivity and the access to water? PMID:25974526

  3. Malignant melanoma arising in melanin-producing medullary thyroid carcinoma

    PubMed Central

    Hirokawa, Mitsuyoshi; Miyauchi, Akira; Otsuru, Minoru; Daa, Tsutomu

    2016-01-01

    Introduction We report a case of malignant melanoma arising in medullary thyroid carcinoma that has not yet been described. Presentation of case A 66-year-old woman presented with a mass in her thyroid. The resected mass was black in color, and was composed of a mixture of classic medullary thyroid carcinoma and pleomorphic atypical cells containing melanin pigments. The pleomorphic atypical cells were morphologically consistent with malignant melanoma, and expressed Melan-A, HMB-45, and S-100 protein as determined by immunohistochemistry. Some of these cells were also positive for calcitonin and chromogranin A. Although the malignant melanoma metastasized to the lymph nodes, the patient remained free from local recurrence and distant metastasis and the primary malignant melanoma lesion was not identified for up to 11 years after the thyroidectomy. Discussion 11 melanin-producing MTC cases have been reported to date. In the reported cases, the term “malignant melanoma” was not used, likely because the melanin-containing carcinoma cells were not morphologically consistent with malignant melanoma, but with medullary carcinoma. Conclusion Malignant melanoma arising in MTC may have a favorable prognosis. PMID:26852361

  4. Vascular leiomyoma of the lung arising from pulmonary artery.

    PubMed

    Terada, Tadashi

    2013-01-01

    Leiomyoma of the lung is extremely rare. The entity is not described in WHO blue book. Less than 100 cases of leiomyoma of the lung have been reported in the literature. However, vascular leiomyoma has not been reported in the literature, to the author's best knowledge. Herein reported is the first case of vascular leiomyoma of the lung arising from smooth muscles of the pulmonary artery. A 62-year-old woman (non-smoker) was found to have a small tumor in the upper lobe in the right lung in routine check. Imaging modalities including CT demonstrated no metastatic lesions. Although clinical cytology and biopsy revealed no malignant cell, right upper lobectomy was performed under the clinical diagnosis of lung carcinoma. Grossly, a white tumor of 1 x 0.8 cm was recognized in the lung. Microscopically, the tumor was connected to the pulmonary arteries. The tumor was composed of mature smooth muscles. Small pulmonary arteries are embedded in the tumor. No lymphatics were seen. Immunohistochemically, the tumor cells were poisitive for alpha-smooth muscle actin, vimentin and Ki-67 (labeling 2%). However, they were negative for cytokeratin (CK) AE1/3, CK CAM5.2, desmin, S100 protein, p53, CD34, KIT, HMB45, estrogen receptor, progesterone receptor, and myoglobin. A pathological diagnosis of primary vascular leiomyoma arising from the smooth muscle of pulmonary artery was made. The patient is now free from tumor, and is now alive 10 year after the operation. PMID:23236548

  5. Mechanism of near-threshold stimulated desorption of protons from transition-metal surfaces

    SciTech Connect

    Melius, C.F.; Stulen, R.H.; Noell, J.O.

    1982-05-17

    The mechanism for near threshold electron and photon stimulated desorption of protons from transition-metal surfaces has been investigated with use of configuration-interaction techniques on finite clusters. The calculations indicate that the protons arise from repulsive states involving double excitations from the metal-hydrogen bonding orbitals and suggest that the process may occur via a surface predissociation mechanism. The calculations are compared to experimental electron stimulated desorption results for Ni<111>.

  6. Theoretical analysis for temperature dependence of laser- induced damage threshold of optical thin films

    NASA Astrophysics Data System (ADS)

    Mikami, K.; Motokoshi, S.; Somekawa, T.; Jitsuno, T.; Fujita, M.; Tanaka, KA; Azechi, H.

    2016-03-01

    The temperature dependence of the laser-induced damage threshold on optical coatings was studied in detail for laser pulses from 123 K to 473 K at different temperatures. The laser-induced damage threshold increased with decreasing temperatures when we tested long pulses (200 ps and 4 ns). The temperature dependence, however, was reversed for pulses shorter than a few picoseconds (100 fs testing). We propose a scaling model with a flowchart that includes three separate processes: free-electron generation, electron multiplication, and electron heating. Furthermore, we calculated the temperature dependence of laser-induced damage thresholds at different temperatures. Our calculation results agreed well with the experimental results.

  7. Thresholds of carcinogenicity of flavors.

    PubMed

    Waddell, William J

    2002-08-01

    Fifteen compounds approved by the FEMA (Flavor and Extract Manufacturers Association) expert panel as GRAS (Generally Recognized As Safe) and structurally related compounds have been reported to be carcinogenic in rodent studies. The dose response of the 15 compounds in these studies was scrutinized by attempting to plot the percentage of animals with tumors against the dose of the compound on a logarithmic scale in molecules of compound per kg per day (the Rozman scale). Four compounds had either no or an inverse dose response: benzaldehyde, furfural, 3,4-dihydroxycoumarin, and gamma-buterolactone. Three had a response at one dose only: anethole, estragole (2 studies), and isophorone. Obviously, a dose-response curve could not be generated for these 7 compounds. Four compounds had an increasing response at two doses (benzyl acetate, cinnamyl anthranilate, ethyl acrylate, and estragole); three compounds had increasing responses at three doses (citral, 2,4-hexadienal, and pyridine); one compound had increasing responses at four doses (methyl eugenol). The three compounds with three doses fit a linear plot with a correlation coefficient of at least 0.9; the four doses in male rats of methyl eugenol fit a linear plot with a correlation coefficient of 0.999983. The intercept at zero percentage tumors of these linear fits was at least several orders of magnitude greater than the estimated daily dose of these flavoring agents to individuals in the United States. This is interpreted to indicate that these flavoring agents have a clear threshold for carcinogenicity in animals that is well above the levels currently approved for use in foods; consequently, these animal studies should not be a cause for concern for carcinogenicity of these compounds in humans. Rather, the animal studies should be viewed as providing evidence for the safety of these compounds at current levels of human exposure. PMID:12151622

  8. Ignition probability of polymer-bonded explosives accounting for multiple sources of material stochasticity

    SciTech Connect

    Kim, S.; Barua, A.; Zhou, M.; Horie, Y.

    2014-05-07

    Accounting for the combined effect of multiple sources of stochasticity in material attributes, we develop an approach that computationally predicts the probability of ignition of polymer-bonded explosives (PBXs) under impact loading. The probabilistic nature of the specific ignition processes is assumed to arise from two sources of stochasticity. The first source involves random variations in material microstructural morphology; the second source involves random fluctuations in grain-binder interfacial bonding strength. The effect of the first source of stochasticity is analyzed with multiple sets of statistically similar microstructures and constant interfacial bonding strength. Subsequently, each of the microstructures in the multiple sets is assigned multiple instantiations of randomly varying grain-binder interfacial strengths to analyze the effect of the second source of stochasticity. Critical hotspot size-temperature states reaching the threshold for ignition are calculated through finite element simulations that explicitly account for microstructure and bulk and interfacial dissipation to quantify the time to criticality (t{sub c}) of individual samples, allowing the probability distribution of the time to criticality that results from each source of stochastic variation for a material to be analyzed. Two probability superposition models are considered to combine the effects of the multiple sources of stochasticity. The first is a parallel and series combination model, and the second is a nested probability function model. Results show that the nested Weibull distribution provides an accurate description of the combined ignition probability. The approach developed here represents a general framework for analyzing the stochasticity in the material behavior that arises out of multiple types of uncertainty associated with the structure, design, synthesis and processing of materials.

  9. Ignition probability of polymer-bonded explosives accounting for multiple sources of material stochasticity

    NASA Astrophysics Data System (ADS)

    Kim, S.; Barua, A.; Horie, Y.; Zhou, M.

    2014-05-01

    Accounting for the combined effect of multiple sources of stochasticity in material attributes, we develop an approach that computationally predicts the probability of ignition of polymer-bonded explosives (PBXs) under impact loading. The probabilistic nature of the specific ignition processes is assumed to arise from two sources of stochasticity. The first source involves random variations in material microstructural morphology; the second source involves random fluctuations in grain-binder interfacial bonding strength. The effect of the first source of stochasticity is analyzed with multiple sets of statistically similar microstructures and constant interfacial bonding strength. Subsequently, each of the microstructures in the multiple sets is assigned multiple instantiations of randomly varying grain-binder interfacial strengths to analyze the effect of the second source of stochasticity. Critical hotspot size-temperature states reaching the threshold for ignition are calculated through finite element simulations that explicitly account for microstructure and bulk and interfacial dissipation to quantify the time to criticality (tc) of individual samples, allowing the probability distribution of the time to criticality that results from each source of stochastic variation for a material to be analyzed. Two probability superposition models are considered to combine the effects of the multiple sources of stochasticity. The first is a parallel and series combination model, and the second is a nested probability function model. Results show that the nested Weibull distribution provides an accurate description of the combined ignition probability. The approach developed here represents a general framework for analyzing the stochasticity in the material behavior that arises out of multiple types of uncertainty associated with the structure, design, synthesis and processing of materials.

  10. The Threshold Level--For Schools?

    ERIC Educational Resources Information Center

    Lauerbach, Gerda

    1979-01-01

    Comments on the document "Threshold Level for Modern Language Learning Schools" (J. A. Van Ek, Strasbourg, 1976) and its appropriateness as a description of learning goals for the first years of foreign language teaching. Criticizes particularly the "reduced learning" concept, on which the threshold projects are based. (IFS/WGA)

  11. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Reporting threshold. 98.81 Section 98.81 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.81 Reporting threshold. You must report...

  12. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.51 Section 98.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report...

  13. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.81 Section 98.81 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.81 Reporting threshold. You must report...

  14. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Reporting threshold. 98.51 Section 98.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report...

  15. 40 CFR 98.111 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Reporting threshold. 98.111 Section 98.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.111 Reporting threshold. You must report...

  16. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Reporting threshold. 98.81 Section 98.81 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.81 Reporting threshold. You must report...

  17. 40 CFR 98.361 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Reporting threshold. 98.361 Section 98.361 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Manure Management § 98.361 Reporting threshold. Livestock facilities must report GHG emissions under this...

  18. 40 CFR 98.361 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.361 Section 98.361 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Manure Management § 98.361 Reporting threshold. Livestock facilities...

  19. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Reporting threshold. 98.461 Section 98.461 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if...

  20. 24 CFR 954.104 - Performance thresholds.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Performance thresholds. 954.104... DEVELOPMENT INDIAN HOME PROGRAM Applying for Assistance § 954.104 Performance thresholds. Applicants must have the administrative capacity to undertake the project proposed, including systems of internal...

  1. 40 CFR 98.111 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.111 Section 98.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.111 Reporting threshold. You must report...

  2. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Reporting threshold. 98.51 Section 98.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report...

  3. 40 CFR 98.181 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Reporting threshold. 98.181 Section 98.181 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Lead Production § 98.181 Reporting threshold. You must report...

  4. STIMULUS AND TRANSDUCER EFFECTS ON THRESHOLD

    PubMed Central

    Flamme, Gregory A.; Geda, Kyle; McGregor, Kara; Wyllys, Krista; Deiters, Kristy K.; Murphy, William J.; Stephenson, Mark R.

    2015-01-01

    Objective This study examined differences in thresholds obtained under Sennheiser HDA200 circumaural earphones using pure tone, equivalent rectangular noise bands, and 1/3 octave noise bands relative to thresholds obtained using Telephonics TDH-39P supra-aural earphones. Design Thresholds were obtained via each transducer and stimulus condition six times within a 10-day period. Study Sample Forty-nine adults were selected from a prior study to represent low, moderate, and high threshold reliability. Results The results suggested that (1) only small adjustments were needed to reach equivalent TDH-39P thresholds, (2) pure-tone thresholds obtained with HDA200 circumaural earphones had reliability equal to or better than those obtained using TDH-39P earphones, (3) the reliability of noise-band thresholds improved with broader stimulus bandwidth and was either equal to or better than pure-tone thresholds, and (4) frequency-specificity declined with stimulus bandwidths greater than one Equivalent Rectangular Band, which could complicate early detection of hearing changes that occur within a narrow frequency range. Conclusions These data suggest that circumaural earphones such as the HDA200 headphones provide better reliability for audiometric testing as compared to the TDH-39P earphones. These data support the use of noise bands, preferably ERB noises, as stimuli for audiometric monitoring. PMID:25549164

  5. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Reporting threshold. 98.461 Section 98.461 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if...

  6. 40 CFR 98.341 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.341 Section 98.341 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.341 Reporting threshold. You...

  7. Applying Threshold Concepts to Finance Education

    ERIC Educational Resources Information Center

    Hoadley, Susan; Wood, Leigh N.; Tickle, Leonie; Kyng, Tim

    2016-01-01

    Purpose: The purpose of this paper is to investigate and identify threshold concepts that are the essential conceptual content of finance programmes. Design/Methodology/Approach: Conducted in three stages with finance academics and students, the study uses threshold concepts as both a theoretical framework and a research methodology. Findings: The…

  8. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Reporting threshold. 98.51 Section 98.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report...

  9. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Reporting threshold. 98.51 Section 98.51 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report...

  10. Intelligence and Creativity: Over the Threshold Together?

    ERIC Educational Resources Information Center

    Welter, Marisete Maria; Jaarsveld, Saskia; van Leeuwen, Cees; Lachmann, Thomas

    2016-01-01

    Threshold theory predicts a positive correlation between IQ and creativity scores up to an IQ level of 120 and no correlation above this threshold. Primary school children were tested at beginning (N = 98) and ending (N = 70) of the school year. Participants performed the standard progressive matrices (SPM) and the Test of Creative…

  11. Network Motif Basis of Threshold Responses

    EPA Science Inventory

    There has been a long-running debate over the existence of thresholds for adverse effects. The difficulty stems from two fundamental challenges: (i) statistical analysis by itself cannot prove the existence of a threshold, i.e., a dose below which there is no effect; and (ii) the...

  12. 40 CFR 98.471 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Reporting threshold. 98.471 Section 98.471 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.471 Reporting threshold. (a) You...

  13. 40 CFR 98.471 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Reporting threshold. 98.471 Section 98.471 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.471 Reporting threshold. (a) You...

  14. 40 CFR 98.471 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Reporting threshold. 98.471 Section 98.471 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Injection of Carbon Dioxide § 98.471 Reporting threshold. (a) You...

  15. Threshold Concepts, Systems and Learning for Sustainability

    ERIC Educational Resources Information Center

    Sandri, Orana Jade

    2013-01-01

    This paper presents a framework for understanding the role that systems theory might play in education for sustainability (EfS). It offers a sketch and critique of Land and Meyer's notion of a "threshold concept", to argue that seeing systems as a threshold concept for sustainability is useful for understanding the processes of…

  16. 40 CFR 98.111 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Reporting threshold. 98.111 Section 98.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.111 Reporting threshold. You must report...

  17. 40 CFR 98.111 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Reporting threshold. 98.111 Section 98.111 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.111 Reporting threshold. You must report...

  18. 40 CFR 98.421 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Reporting threshold. 98.421 Section 98.421 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.421 Reporting threshold. Any supplier...

  19. 40 CFR 98.421 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Reporting threshold. 98.421 Section 98.421 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Carbon Dioxide § 98.421 Reporting threshold. Any supplier...

  20. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.461 Section 98.461 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if...

  1. 40 CFR 98.231 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.231 Section 98.231 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Petroleum and Natural Gas Systems § 98.231 Reporting threshold. (a)...

  2. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Reporting threshold. 98.461 Section 98.461 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if...

  3. Choice deferral can arise from absolute evaluations or relative comparisons.

    PubMed

    White, Chris M; Hoffrage, Ulrich; Reisen, Nils

    2015-06-01

    When choosing among several options, people may defer choice for either of 2 reasons: because none of the options is good enough or because there is uncertainty regarding which is the best. These reasons form the basis of the 2-stage, 2-threshold (2S2T) framework, which posits that a different kind of processing corresponds to these 2 reasons for choice deferral: absolute evaluations and relative comparisons, respectively. Three experiments are reported in which each type of processing was triggered in different conditions either via different payoff structures or different degrees of attribute knowledge. The effects of the 3 main independent variables (the size of the choice set, the utility of the best option, and the number of competitive options) differed depending on the payoff structure or attribute knowledge conditions in ways predicted by the 2S2T framework. Implications for consumer decision making, marketing, and eyewitness identification are discussed. PMID:25938974

  4. Representation of discrete Steklov-Poincare operator arising in domain decomposition methods in wavelet basis

    SciTech Connect

    Jemcov, A.; Matovic, M.D.

    1996-12-31

    This paper examines the sparse representation and preconditioning of a discrete Steklov-Poincare operator which arises in domain decomposition methods. A non-overlapping domain decomposition method is applied to a second order self-adjoint elliptic operator (Poisson equation), with homogeneous boundary conditions, as a model problem. It is shown that the discrete Steklov-Poincare operator allows sparse representation with a bounded condition number in wavelet basis if the transformation is followed by thresholding and resealing. These two steps combined enable the effective use of Krylov subspace methods as an iterative solution procedure for the system of linear equations. Finding the solution of an interface problem in domain decomposition methods, known as a Schur complement problem, has been shown to be equivalent to the discrete form of Steklov-Poincare operator. A common way to obtain Schur complement matrix is by ordering the matrix of discrete differential operator in subdomain node groups then block eliminating interface nodes. The result is a dense matrix which corresponds to the interface problem. This is equivalent to reducing the original problem to several smaller differential problems and one boundary integral equation problem for the subdomain interface.

  5. Transversely isotropic poroelasticity arising from thin isotropic layers

    SciTech Connect

    Berryman, J.G.

    1996-11-01

    Percolation phenomena play central roles in the field of poroelasticity, where two distinct sets of percolating continua intertwine. A connected solid frame forms the basis of the elastic behavior of a poroelastic medium in the presence of confining forces, while connected pores permit a percolating fluid (if present) to influence the mechanical response of the system from within. The present paper discusses isotropic and anisotropic poroelastic media and establishes general formulas for the behavior of transversely isotropic poroelasticity arising from laminations of isotropic components. The Backus averaging method is shown to provide elementary means of constructing general formulas. The results for confined fluids are then compared with the more general Gassmann formulas that must be satisfied by any anisotropic poroelastic medium and found to be in complete agreement.

  6. Carcinosarcoma arising from uterine adenomyosis: A case report.

    PubMed

    Kiuchi, Kaori; Hasegawa, Kiyoshi; Kanamori, Anriko; Machida, Hiromi; Kojima, Masaru; Fukasawa, Ichio

    2016-03-01

    Carcinosarcoma arising from uterine adenomyosis is extremely rare. We encountered such a patient and herein provide a review of the literature. A 56-year-old woman was referred for a huge pelvic tumor, suspected to be an advanced uterine leiomyosarcoma. Intraoperative inspection revealed a mass, mainly located in the uterine myometrium, invading the uterine serosa. The tumor had previously spontaneously ruptured and disseminated to the pelvic cavity. Pathological and immunohistochemical examination revealed an infiltrative pattern of biphasic tumor cells composed of endometrioid adenocarcinoma and a nonepithelial component with rhabdomyosarcomatous differentiation. Benign endometrial glands with stromal cells were found adjacent to the area of the carcinosarcoma. The endometrium and both ovaries and fallopian tubes were microscopically free of tumor cells. The final diagnosis was heterologous type carcinosarcoma with rhabdomyosarcomatous differentiation, originating from uterine adenomyosis. PMID:26663238

  7. Hairy Polyp of the Nasopharynx Arising from the Eustachian Tube.

    PubMed

    Wu, Judy; Schulte, Jefree; Yang, Carina; Baroody, Fuad; Ginat, Daniel Thomas

    2016-06-01

    Hairy polyps of the nasopharynx display characteristic radiological imaging findings, including the presence of fat in the polypoid mass. Furthermore, diagnostic imaging is useful for delineating the site of origin of these lesions, which can facilitate surgical planning. For instance hairy polyps that arise from the right Eustachian tube can be amputated via a trans-nasal approach with endoscopy, but may necessitate a two stage approach in order to avoid injury to critical structures, such as the internal carotid artery. On histology, hairy polyps comprise an outer keratinizing squamous epithelium with adnexal tissue, including hair follicles, and central fibroadipose and cartilaginous tissue. These features are exemplified in this sine qua non radiology-pathology correlation article. PMID:25939422

  8. Extravasation Mucocele Arising from a Lingual Thyroglossal Duct Remnant

    PubMed Central

    Nakahira, Mitsuhiko; Nakatani, Hiroaki

    2015-01-01

    Although a thyroglossal duct cyst is a congenital anomaly, it can also appear in adults. Despite the presence of embryological remnants, it is still unclear why the cyst should suddenly develop later in life. We report a case of a 46-year-old male with an extravasation mucocele arising from a long-standing lingual thyroglossal duct remnant. MRI demonstrated a lingual cystic lesion near the hyoid bone associated with a suprahyoid tract-like structure masquerading as a thyroglossal duct cyst. However, histopathological examination demonstrated a mucocele secondary to a rupture of a thyroglossal duct remnant with numerous intramural heterotopic salivary glands. We propose a new mechanism of an acquired cystic formation of this congenital disease that excessive production of mucus from heterotopic salivary glands and a physical trauma such as swallowing may lead to extravasation of mucus from the thyroglossal duct. PMID:25861502

  9. Irregular activity arises as a natural consequence of synaptic inhibition

    SciTech Connect

    Terman, D.; Rubin, J. E.; Diekman, C. O.

    2013-12-15

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects.

  10. Extravasation mucocele arising from a lingual thyroglossal duct remnant.

    PubMed

    Nakahira, Mitsuhiko; Nakatani, Hiroaki

    2015-01-01

    Although a thyroglossal duct cyst is a congenital anomaly, it can also appear in adults. Despite the presence of embryological remnants, it is still unclear why the cyst should suddenly develop later in life. We report a case of a 46-year-old male with an extravasation mucocele arising from a long-standing lingual thyroglossal duct remnant. MRI demonstrated a lingual cystic lesion near the hyoid bone associated with a suprahyoid tract-like structure masquerading as a thyroglossal duct cyst. However, histopathological examination demonstrated a mucocele secondary to a rupture of a thyroglossal duct remnant with numerous intramural heterotopic salivary glands. We propose a new mechanism of an acquired cystic formation of this congenital disease that excessive production of mucus from heterotopic salivary glands and a physical trauma such as swallowing may lead to extravasation of mucus from the thyroglossal duct. PMID:25861502

  11. Criminal prosecution arising from medical mishaps: a Japanese perspective.

    PubMed

    Tsukamoto, Yasushi

    2005-12-01

    In Japan, the number of physicians being investigated on suspicion of medical malpractice has increased. Specifically, the criminal prosecutions arising from professional negligence resulting in bodily injury or death have also increased. Article 21 of the Japanese Physician's Act compels a doctor to notify the district police when he diagnoses a death to be 'unnatural'. Originally this provision was to increase public safety through crime detection, but one recent criminal case broadened the application of this article to include the death from a mishap during medical treatment. This criminal case made a tremendous impact on physicians, as the convictions and sentences forced physicians to notify the police even when it is not certain the patient died of the malady or of the medical misconduct itself. Besides, we wonder if such obligation of doctors to notify such 'unnatural' death from medical mishap may be against a person's privilege against self-incrimination which is assured by Japanese Constitutional Law (article 38). PMID:16440862

  12. Irregular activity arises as a natural consequence of synaptic inhibition

    NASA Astrophysics Data System (ADS)

    Terman, D.; Rubin, J. E.; Diekman, C. O.

    2013-12-01

    Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects.

  13. Arthroscopic Resection of Wrist Ganglion Arising from the Lunotriquetral Joint

    PubMed Central

    Mak, Michael C. K.; Ho, Pak-cheong; Tse, W. L.; Wong, Clara W. Y.

    2013-01-01

    The dorsal wrist ganglion is the most common wrist mass, and previous studies have shown that it arises from the scapholunate interval in the vast majority of cases. Treatment has traditionally been open excision, and more recently arthroscopic resection has been established as an effective and less invasive treatment method. However, application of this technique to ganglia in atypical locations has not been reported, where open excision is the usual practice. This report describes two cases of atypical dorsal wrist ganglia that arose from the lunotriquetral (LT) joint, demonstrated by arthroscopic visualization and wrist arthrogram in one of them. Arthroscopic resection was performed, and the application of this technique to a dorsal wrist ganglion with an atypical origin and location is described. PMID:24436842

  14. Acute mediastinitis arising from pancreatic mediastinal fistula in recurrent pancreatitis

    PubMed Central

    Choe, In Soo; Kim, Yong Seok; Lee, Tae Hee; Kim, Sun Moon; Song, Kyung Ho; Koo, Hoon Sup; Park, Jung Ho; Pyo, Jin Sil; Kim, Ji Yeong; Choi, In Seok

    2014-01-01

    Acute mediastinitis is a fatal disease that usually originates from esophageal perforation and surgical infection. Rare cases of descending necrotizing mediastinitis can occur following oral cavity and pharynx infection or can be a complication of pancreatitis. The most common thoracic complications of pancreatic disease are reactive pleural effusion and pneumonia, while rare complications include thoracic conditions, such as pancreaticopleural fistula with massive pleural effusion or hemothorax and extension of pseudocyst into the mediastinum. There have been no reports of acute mediastinitis originating from pancreatitis in South Korea. In this report, we present the case of a 50-year-old female suffering from acute mediastinitis with pleural effusion arising from recurrent pancreatitis that improved after surgical intervention. PMID:25356062

  15. Methods for automatic trigger threshold adjustment

    DOEpatents

    Welch, Benjamin J; Partridge, Michael E

    2014-03-18

    Methods are presented for adjusting trigger threshold values to compensate for drift in the quiescent level of a signal monitored for initiating a data recording event, thereby avoiding false triggering conditions. Initial threshold values are periodically adjusted by re-measuring the quiescent signal level, and adjusting the threshold values by an offset computation based upon the measured quiescent signal level drift. Re-computation of the trigger threshold values can be implemented on time based or counter based criteria. Additionally, a qualification width counter can be utilized to implement a requirement that a trigger threshold criterion be met a given number of times prior to initiating a data recording event, further reducing the possibility of a false triggering situation.

  16. Unilateral Eye Blinking Arising From the Ictal Ipsilateral Occipital Area.

    PubMed

    Falsaperla, Raffaele; Perciavalle, Valentina; Pavone, Piero; Praticò, Andrea Domenico; Elia, Maurizio; Ruggieri, Martino; Caraballo, Roberto; Striano, Pasquale

    2016-07-01

    We report on an 18-month-old boy with unilateral left eye blinking as a single ictal manifestation without facial twitching. The clinical onset of this phenomenon was first recorded (as an occasional event) at age 3 months, and it was overlooked. By age 6 months, the child's blinking increased to almost daily occurrence in clusters: during blinking the infant showed intact awareness and occasional jerks in the upper limbs and right leg. A video-electroencephalography (video-EEG) documented clinical correlation with a focal pattern arising from the left occipital region, and brain magnetic resonance imaging (MRI) revealed severe brain damage, consisting in poroencephalic hollows and increased spaces in the convexities involving a large area of the left cerebral hemisphere. The boy was prescribed sodium valproate (30 mg/kg/d), resulting in drastic reduction of his clinical seizures. Follow-up to his current age documented good general status, with persistent partial right hemilateral seizures. The blinking progressively disappeared, and is no longer recorded. The pathogenic hypotheses of the unilateral ictal blinking include involvement of the ipsilateral cerebral hemisphere and/or the cerebellar pathways. Review of previous reports of unilateral eye blinking, arising from the ictal ipsilateral brain, revealed that different damaged regions may give rise to blinking ictal phenomena, likely via the trigeminal fibres innervating the subdural intracranial structures and the pial vessels in the ipsilateral affected brain. The eye blinking in the present child represents a further example of an ictal phenomenon, which is predictive of the damaged brain region. PMID:25179638

  17. Effects of pump recycling technique on stimulated Brillouin scattering threshold: a theoretical model.

    PubMed

    Al-Asadi, H A; Al-Mansoori, M H; Ajiya, M; Hitam, S; Saripan, M I; Mahdi, M A

    2010-10-11

    We develop a theoretical model that can be used to predict stimulated Brillouin scattering (SBS) threshold in optical fibers that arises through the effect of Brillouin pump recycling technique. Obtained simulation results from our model are in close agreement with our experimental results. The developed model utilizes single mode optical fiber of different lengths as the Brillouin gain media. For 5-km long single mode fiber, the calculated threshold power for SBS is about 16 mW for conventional technique. This value is reduced to about 8 mW when the residual Brillouin pump is recycled at the end of the fiber. The decrement of SBS threshold is due to longer interaction lengths between Brillouin pump and Stokes wave. PMID:20941134

  18. Dark matter searches for monoenergetic neutrinos arising from stopped meson decay in the Sun

    SciTech Connect

    Rott, Carsten; In, Seongjin; Kumar, Jason; Yaylali, David

    2015-11-24

    Dark matter can be gravitationally captured by the Sun after scattering off solar nuclei. Annihilations of the dark matter trapped and accumulated in the centre of the Sun could result in one of the most detectable and recognizable signals for dark matter. Searches for high-energy neutrinos produced in the decay of annihilation products have yielded extremely competitive constraints on the spin-dependent scattering cross sections of dark matter with nuclei. Recently, the low energy neutrino signal arising from dark-matter annihilation to quarks which then hadronize and shower has been suggested as a competitive and complementary search strategy. These high-multiplicity hadronic showers give rise to a large amount of pions which will come to rest in the Sun and decay, leading to a unique sub-GeV neutrino signal. We here improve on previous works by considering the monoenergetic neutrino signal arising from both pion and kaon decay. We consider searches at liquid scintillation, liquid argon, and water Cherenkov detectors and find very competitive sensitivities for few-GeV dark matter masses.

  19. Dark matter searches for monoenergetic neutrinos arising from stopped meson decay in the Sun

    NASA Astrophysics Data System (ADS)

    Rott, Carsten; In, Seongjin; Kumar, Jason; Yaylali, David

    2015-11-01

    Dark matter can be gravitationally captured by the Sun after scattering off solar nuclei. Annihilations of the dark matter trapped and accumulated in the centre of the Sun could result in one of the most detectable and recognizable signals for dark matter. Searches for high-energy neutrinos produced in the decay of annihilation products have yielded extremely competitive constraints on the spin-dependent scattering cross sections of dark matter with nuclei. Recently, the low energy neutrino signal arising from dark-matter annihilation to quarks which then hadronize and shower has been suggested as a competitive and complementary search strategy. These high-multiplicity hadronic showers give rise to a large amount of pions which will come to rest in the Sun and decay, leading to a unique sub-GeV neutrino signal. We here improve on previous works by considering the monoenergetic neutrino signal arising from both pion and kaon decay. We consider searches at liquid scintillation, liquid argon, and water Cherenkov detectors and find very competitive sensitivities for few-GeV dark matter masses.

  20. Post Traumatic Pseudoaneurysm Arising from V4 Segment of Vertebral Artery: A Case Report.

    PubMed

    Huh, Chae Wook; Nam, Kyoung Hyup; Choi, Chang Hwa; Lee, Jae Il

    2015-10-01

    This case report describes a traumatic pseudoaneurysm arising from the right V4 segment of the vertebral artery, near the origin of the posterior inferior cerebellar artery. Post-traumatic vertebral artery pseudoaneurysm is rare, but associated with a high mortality rate. We report on an extremely rare case of post-traumatic pseudoaneurysm of the vertebral artery with delayed manifestation. A 9-year-old child was admitted to the emergency room after a pedestrian car accident. A computed tomography (CT) scan showed subarachnoid hemorrhage with intraventricular hemorrhage (IVH), multiple facial bones, and temporal bone fracture. External ventricular drainage and decompressive suboccipital craniectomy were performed for acute hydrocephalus and posterior fossa swelling. The patient's clinical condition became suddenly aggravated on the 15th hospital day, and brain CT confirmed appearance of a new 4th ventricle IVH. Digital subtraction angiography revealed a ruptured pseudoaneurysm arising from the right V4 segment of the vertebral artery. Parent artery occlusion using detachable coils was achieved. Despite intensive care, the patient's clinical condition showed continuous deterioration and the patient died of respiratory complications on the 52nd hospital day. PMID:27169084

  1. Fundamental threshold of chaos in some nonlinear oscillators

    SciTech Connect

    Ryabov, V.B.

    1996-06-01

    A technique for predicting chaos arising in a broad class of nonlinear oscillatory systems is proposed. It is based on the notion of running Lyapunov exponents and uses the local stability properties of trajectories for determining the {open_quote}{open_quote}safe{close_quote}{close_quote} areas in the phase space where any trajectory is regular and stable in the sense of Lyapunov. The combination of this approach with harmonic balance method permits to obtain the corresponding {open_quote}{open_quote}safe{close_quote}{close_quote} regions in the control parameter space. The borders of these regions may be considered as threshold lines delimiting the areas of possible chaotic instability. An example of the two-well Duffing oscillator demonstrates good agreement between theoretically predicted values of control parameters where chaos arises with those obtained numerically. The technique is especially effective for rather high dissipation levels when other known methods such as Melnikov{close_quote}s criterion or combination of harmonic balance with analysis of variational equations fail to provide correct results. {copyright} {ital 1996 American Institute of Physics.}

  2. A Threshold Continuum for Aeolian Sand Transport

    NASA Astrophysics Data System (ADS)

    Swann, C.; Ewing, R. C.; Sherman, D. J.

    2015-12-01

    The threshold of motion for aeolian sand transport marks the initial entrainment of sand particles by the force of the wind. This is typically defined and modeled as a singular wind speed for a given grain size and is based on field and laboratory experimental data. However, the definition of threshold varies significantly between these empirical models, largely because the definition is based on visual-observations of initial grain movement. For example, in his seminal experiments, Bagnold defined threshold of motion when he observed that 100% of the bed was in motion. Others have used 50% and lesser values. Differences in threshold models, in turn, result is large errors in predicting the fluxes associated with sand and dust transport. Here we use a wind tunnel and novel sediment trap to capture the fractions of sand in creep, reptation and saltation at Earth and Mars pressures and show that the threshold of motion for aeolian sand transport is best defined as a continuum in which grains progress through stages defined by the proportion of grains in creep and saltation. We propose the use of scale dependent thresholds modeled by distinct probability distribution functions that differentiate the threshold based on micro to macro scale applications. For example, a geologic timescale application corresponds to a threshold when 100% of the bed in motion whereas a sub-second application corresponds to a threshold when a single particle is set in motion. We provide quantitative measurements (number and mode of particle movement) corresponding to visual observations, percent of bed in motion and degrees of transport intermittency for Earth and Mars. Understanding transport as a continuum provides a basis for revaluating sand transport thresholds on Earth, Mars and Titan.

  3. Quantifying Colocalization: Thresholding, Void Voxels and the Hcoef

    PubMed Central

    Adler, Jeremy; Parmryd, Ingela

    2014-01-01

    A critical step in the analysis of images is identifying the area of interest e.g. nuclei. When the nuclei are brighter than the remainder of the image an intensity can be chosen to identify the nuclei. Intensity thresholding is complicated by variations in the intensity of individual nuclei and their intensity relative to their surroundings. To compensate thresholds can be based on local rather than global intensities. By testing local thresholding methods we found that the local mean performed poorly while the Phansalkar method and a new method based on identifying the local background were superior. A new colocalization coefficient, the Hcoef, highlights a number of controversial issues. (i) Are molecular interactions measurable (ii) whether to include voxels without fluorophores in calculations, and (iii) the meaning of negative correlations. Negative correlations can arise biologically (a) because the two fluorophores are in different places or (b) when high intensities of one fluorophore coincide with low intensities of a second. The cases are distinct and we argue that it is only relevant to measure correlation using pixels that contain both fluorophores and, when the fluorophores are in different places, to just report the lack of co-occurrence and omit these uninformative negative correlation. The Hcoef could report molecular interactions in a homogenous medium. But biology is not homogenous and distributions also reflect physico-chemical properties, targeted delivery and retention. The Hcoef actually measures a mix of correlation and co-occurrence, which makes its interpretation problematic and in the absence of a convincing demonstration we advise caution, favouring separate measurements of correlation and of co-occurrence. PMID:25375829

  4. Should the current DSM-IV-TR definition for PTSD be expanded to include serial and multiple microtraumas as aetiologies?

    PubMed

    Seides, R

    2010-10-01

    Post-traumatic stress disorder (PTSD) is an anxiety disorder that develops from events that are interpreted as traumatic. It may be secondary to witnessing trauma to someone close, an event that threatens one's life or childhood sexual trauma. Resultant feelings can be fear, helplessness or horror. Thresholds at which traumatic events cause PTSD, the individual's coping ability and support systems help determine occurrence and severity of symptoms. According to DSM-IV-TR (DSM) definition, PTSD can occur after childhood sexual abuse or a single trauma threatening life or safety. However, it is becoming clearer that symptoms of PTSD can arise from multiple less severe traumas ('microtraumas'), which can be a consequence of a history of longstanding emotional neglect, humiliation or inaccurate attribution of blame. The DSM should consider modifying the criteria to include multiple microtraumas that can lead to PTSD symptoms and may even be more destructive to psychological health. PMID:21050339

  5. Small bowel adenocarcinoma arising in a patient with hereditary hemorrhagic telangiectasia: A case report

    PubMed Central

    YOSHIOKA, YUICHIRO; NOZAWA, HIROAKI; TANAKA, JUNICHIRO; NISHIKAWA, TAKESHI; TANAKA, TOSHIAKI; KIYOMATSU, TOMOMICHI; KAWAI, KAZUSHIGE; HATA, KEISUKE; KAZAMA, SHINSUKE; YAMAGUCHI, HIRONORI; ISHIHARA, SOICHIRO; SUNAMI, EIJI; KITAYAMA, JOJI; WATANABE, TOSHIAKI

    2016-01-01

    Patients with hereditary hemorrhagic telangiectasia (HHT) are reportedly at a lower overall risk of malignancies, and small bowel adenocarcinoma (SBA) arising in a HHT patient is extremely rare. In this study, the case of a 37-year-old female with HHT who developed a poorly differentiated jejunal adenocarcinoma five years after ileocecal resection for multiple colonic adenomas is presented. The patient underwent curative resection of the cancer invading the ileum and the mesentery of the transverse colon, but had to overcome critical complications perioperatively, stemming from HHT-associated peripheral capillary dilatation and arteriovenous malformation, including nosebleeds and possible infusion-induced air embolism through pulmonary shunts. The patient subsequently received adjuvant chemotherapy including capecitabine and oxaliplatin for 6 months, and currently remains alive without any evidence of recurrence 12 months after the second surgery. This patient with SBA was an instructive case demonstrating the necessity of careful attention during major surgery in HHT. PMID:26998137

  6. Aging and multiple sclerosis.

    PubMed

    Sanai, Shaik Ahmed; Saini, Vasu; Benedict, Ralph Hb; Zivadinov, Robert; Teter, Barbara E; Ramanathan, Murali; Weinstock-Guttman, Bianca

    2016-05-01

    The life expectancy and average age of persons with multiple sclerosis (MS) have increased significantly during the last two decades. The introduction of disease-modifying therapies and a better delineation and understanding of the superimposed comorbidities often diagnosed in MS patients are probably the most important factors accountable for the increase in aging MS population worldwide. Healthcare teams must therefore address the problems arising due to advancing age superimposed on this chronic neurologic disease. In this review, we focus on the physiology of aging, its effects on MS disease course, and the pathological and immunological changes associated with aging and disease progression. Additionally, we discuss the common comorbidities that occur in aging persons with MS that may arise either as a result of the aging process or from relentless chronic MS disease progression as well as the challenges on differentiating the two processes for a more appropriate therapeutic approach. PMID:26895718

  7. Evaluation of different methods for determining growing degree-day thresholds in apricot cultivars

    NASA Astrophysics Data System (ADS)

    Ruml, Mirjana; Vuković, Ana; Milatović, Dragan

    2010-07-01

    The aim of this study was to examine different methods for determining growing degree-day (GDD) threshold temperatures for two phenological stages (full bloom and harvest) and select the optimal thresholds for a greater number of apricot ( Prunus armeniaca L.) cultivars grown in the Belgrade region. A 10-year data series were used to conduct the study. Several commonly used methods to determine the threshold temperatures from field observation were evaluated: (1) the least standard deviation in GDD; (2) the least standard deviation in days; (3) the least coefficient of variation in GDD; (4) regression coefficient; (5) the least standard deviation in days with a mean temperature above the threshold; (6) the least coefficient of variation in days with a mean temperature above the threshold; and (7) the smallest root mean square error between the observed and predicted number of days. In addition, two methods for calculating daily GDD, and two methods for calculating daily mean air temperatures were tested to emphasize the differences that can arise by different interpretations of basic GDD equation. The best agreement with observations was attained by method (7). The lower threshold temperature obtained by this method differed among cultivars from -5.6 to -1.7°C for full bloom, and from -0.5 to 6.6°C for harvest. However, the “Null” method (lower threshold set to 0°C) and “Fixed Value” method (lower threshold set to -2°C for full bloom and to 3°C for harvest) gave very good results. The limitations of the widely used method (1) and methods (5) and (6), which generally performed worst, are discussed in the paper.

  8. Sputtering Threshold Energies of Heavy Ions

    NASA Technical Reports Server (NTRS)

    Mantenieks, Maris A.

    1999-01-01

    Sputter erosion in ion thrusters has been measured in lifetests at discharge voltages as low as 25 V. Thruster operation at this discharge voltage results in component erosion rates sufficiently low to satisfy most mission requirements. It has been recognized that most of the internal sputtering in ion thrusters is done by doubly charged ions. Knowledge of the sputtering threshold voltage of a xenon molybdenum system would be beneficial in understanding the sputtering process as well as making more accurate calculations of the sputtering rates of ion thruster components. Sputtering threshold energies calculated from various formulations found in the literature results in values ranging from 28 to 200 eV. It is evident that some of these formulations cannot be relied upon to provide sputtering thresholds with any degree of accuracy. This paper re-examines the threshold energies measurements made in the early sixties by Askerov and Sena, and Stuart and Wehner. The threshold voltages as derived by Askerov and au have been reevaluated by using a different extrapolation method of sputter yields at low ion energies. The resulting threshold energies are in general similar to those measured by Stuart and Wehner. An empirical relationship is derived,for mercury and xenon ions for the ratio of the sputtering threshold energy to the sublimation energy as a function of the ratio of target to ion atomic mass.

  9. Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

    USGS Publications Warehouse

    Black, R.W.; Moran, P.W.; Frankforter, J.D.

    2011-01-01

    Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. Although nutrients typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria. ?? 2010 The Author(s).

  10. Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams.

    PubMed

    Black, Robert W; Moran, Patrick W; Frankforter, Jill D

    2011-04-01

    Many streams within the United States are impaired due to nutrient enrichment, particularly in agricultural settings. The present study examines the response of benthic algal communities in agricultural and minimally disturbed sites from across the western United States to a suite of environmental factors, including nutrients, collected at multiple scales. The first objective was to identify the relative importance of nutrients, habitat and watershed features, and macroinvertebrate trophic structure to explain algal metrics derived from deposition and erosion habitats. The second objective was to determine if thresholds in total nitrogen (TN) and total phosphorus (TP) related to algal metrics could be identified and how these thresholds varied across metrics and habitats. Nutrient concentrations within the agricultural areas were elevated and greater than published threshold values. All algal metrics examined responded to nutrients as hypothesized. Although nutrients typically were the most important variables in explaining the variation in each of the algal metrics, environmental factors operating at multiple scales also were important. Calculated thresholds for TN or TP based on the algal metrics generated from samples collected from erosion and deposition habitats were not significantly different. Little variability in threshold values for each metric for TN and TP was observed. The consistency of the threshold values measured across multiple metrics and habitats suggest that the thresholds identified in this study are ecologically relevant. Additional work to characterize the relationship between algal metrics, physical and chemical features, and nuisance algal growth would be of benefit to the development of nutrient thresholds and criteria. PMID:20577796

  11. Differential diagnosis of BPOP arising in relation to patella

    PubMed Central

    Pal, Jitendra Nath; Kar, Maitreyee; Hazra, Sunit; Basu, Anindya

    2015-01-01

    bizarre parosteal osteochondromatous proliferation’. There is no recurrence in five years of follow up. Conclusion: When exostosis like lesions arise from unusual site and at an unusual age group, other rare conditions need to be investigated. Though the final diagnosis of BPOP is obtained after careful histo-pathological examination, the clinico-radiological findings are also relevant. As literature search indicates, this is possibly second incidence where BPOP arised from sesamoid bone and first from patella. PMID:27299085

  12. Experimental realization of chaos control by thresholding.

    PubMed

    Murali, K; Sinha, Sudeshna

    2003-07-01

    We report the experimental verification of thresholding as a versatile tool for efficient and flexible chaos control. The strategy here simply involves monitoring a single state variable and resetting it when it exceeds a threshold. We demonstrate the success of the technique in rapidly controlling different chaotic electrical circuits, including a hyperchaotic circuit, onto stable fixed points and limit cycles of different periods, by thresholding just one variable. The simplicity of this controller entailing no run-time computation, and the ease and rapidity of switching between different targets it offers, suggests a potent tool for chaos based applications. PMID:12935228

  13. A Stochastic Problem Arising in the Storage of Radioactive Waste

    SciTech Connect

    Williams, M.M.R.

    2004-07-15

    Nuclear waste drums can contain a collection of radioactive components of uncertain activity and randomly dispersed in position. This implies that the dose-rate at the surface of different drums in a large assembly of similar drums can have significant variations according to the physical makeup and configuration of the waste components. The present paper addresses this problem by treating the drum, and its waste, as a stochastic medium. It is assumed that the sources in the drum contribute a dose-rate to some external point. The strengths and positions are chosen by random numbers, the dose-rate is calculated and, from several thousand realizations, a probability distribution for the dose-rate is obtained. It is shown that a very close approximation to the dose-rate probability function is the log-normal distribution. This allows some useful statistical indicators, which are of environmental importance, to be calculated with little effort.As an example of a practical situation met in the storage of radioactive waste containers, we study the problem of 'hotspots'. These arise in drums in which most of the activity is concentrated on one radioactive component and hence can lead to the possibility of large surface dose-rates. It is shown how the dose-rate, the variance, and some other statistical indicators depend on the relative activities on the sources. The results highlight the importance of such hotspots and the need to quantify their effect.

  14. Primary seminoma arising in the middle mediastinum: A case report

    PubMed Central

    XU, JING; ZHAO, JINGLAN; GENG, SHAOQING; WANG, QI; WANG, PENGFEI; ZHANG, CHUNLING; ZHU, XIONGZENG; JI, YOUXIN

    2016-01-01

    Primary mediastinal seminoma often occurs in the anterior mediastinum of young males. It is unusual for the tumor to originate in the middle or posterior mediastinum, and such cases have rarely been reported in the English literature. The present study reports the case of a 52-year-old man with a 3.0-cm primary seminoma arising in the middle mediastinum. The patient presented with the symptoms of cough and chest tightness. Fluorine-18 fluorodeoxyglucose-positron emission tomography (18F-FDG-PET) scans revealed unique abnormal FDG uptake in the middle mediastinum. A mediastinoscopy was performed and integral excision was found to be difficult. A biopsy was performed and the histological examination revealed a primary seminoma. Following 4 cycles of a standard bleomycin, etoposide and cisplatin chemotherapy regimen, and chest irradiation at a total dose of 40 Gy in 20 fractions, the tumor exhibited a partial response, decreasing in size, and FDG uptake was no longer observed on 18F-FDG-PET scan. The last follow-up date was April 2016 and the patient has remained disease-free for 20 months. PMID:27347149

  15. Results of Surgical Treatment of Schwannomas Arising from Extremities

    PubMed Central

    Urban, Maciej; Wnukiewicz, Witold; Reichert, Paweł; Ziółkowski, Piotr

    2015-01-01

    Schwannomas are benign neoplasms derived from Schwann cells. In this work, we present our experience in operative management of schwannomas and analyse results of treatment. Clinical material consisted of 34 patients, in whom 44 schwannomas located in extremities were excised between 1985 and 2013. Thirty-five tumours originated from major peripheral nerves and 9 from small nerve branches. Postoperatively, in the first group of tumours, pain resolved in 100%, paresthesias in 83.3%, and Hoffmann-Tinel sign in 91.6% of the patients. Improvement in motor function was noted in 28.5% of the cases, in sensory function: complete in 70%, and partial in 15%. The most frequently affected major peripheral nerves were the ulnar (11 tumours) and median (5 tumours) nerves. Schwannomas originating from small nerve branches were removed without identification of the site of origin. After their resection, definitive healing was achieved. Conclusions. (1) Schwannomas located in extremities arise predominantly from major peripheral nerves, most commonly the ulnar and median nerves. (2) Gradual tumour growth causes exacerbation of compression neuropathy, creating an indication for surgery. (3) In most cases, improvement in peripheral nerve function after excision of schwannoma is achieved. (4) The risk of new permanent postoperative neurological deficits is low. PMID:25793198

  16. Unusual gestational choriocarcinoma arising in an interstitial pregnancy

    PubMed Central

    Meddeb, Sawsen; Rhim, Mohamed Salah; Zarrouk, Wissal; Bibi, Mohamed; Yacoubi, Mohamed Tahar; Khairi, Hedi

    2014-01-01

    INTRODUCTION Choriocarcinoma is a highly malignant trophoblastic neoplasm. Its association with ectopic pregnancy is very rare and usually with aggressive behavior. PRESENTATION OF CASE We report a new case arising in an interstitial pregnancy occurring in a 46-year-old woman. The patient was admitted for severe pelvic pain and abundant metrorrhagia. One month ago, she had had a laparoscopic resection of an interstitial pregnancy subsequent to failure of chemotherapy by methotrexate. The raise of serum βhCG level and the hyperechoic intrauterine mass were in favor of gestational trophoblastic disease. Urgent laparotomy was performed for circulatory collapse. Hysterectomy was done. Histological examination revealed a choriocarcinoma. The patient underwent chemotherapy. Two years later, neither metastasis nor recurrence was detected. DISCUSSION Clinical diagnosis of primary interstitial choriocarcinoma is difficult, since it is rare and manifesting by non-specific abnormal vaginal bleeding. Imaging findings are also not helpful in ectopic location. The frequency of metastasis is related to the delayed diagnosis. Serial measurement of βhCG level was the most useful marker of diagnosis and follow up. Histopathological examination remains the only tool of the precise diagnosis. Choriocarcinoma has a very good prognosis even in advanced stages, since it is very chemosensitive. CONCLUSION The current trend of the treatment of ectopic pregnancy by conservative surgery requires adequate monitoring of βhCG and careful examination of pathologic specimens to avoid misdiagnosis of ectopic gestational trophoblastic disease. PMID:25290382

  17. Proprioceptive recalibration arises slowly compared to reach adaptation.

    PubMed

    Zbib, Basel; Henriques, Denise Y P; Cressman, Erin K

    2016-08-01

    When subjects reach in a novel visuomotor environment (e.g. while viewing a cursor representing their hand that is rotated from their hand's actual position), they typically adjust their movements (i.e. bring the cursor to the target), thus reducing reaching errors. Additionally, research has shown that reaching with altered visual feedback of the hand results in sensory changes, such that proprioceptive estimates of hand position are shifted in the direction of the visual feedback experienced (Cressman and Henriques in J Neurophysiol 102:3505-3518, 2009). This study looked to establish the time course of these sensory changes. Additionally, the time courses of implicit sensory and motor changes were compared. Subjects reached to a single visual target while seeing a cursor that was either aligned with their hand position (50 trials) or rotated 30° clockwise relative to their hand (150 trials). Reach errors and proprioceptive estimates of felt hand position were assessed following the aligned reach training trials and at seven different times during the rotated reach training trials by having subjects reach to the target without visual feedback, and provide estimates of their hand relative to a visual reference marker, respectively. Results revealed a shift in proprioceptive estimates throughout the rotated reach training trials; however, significant sensory changes were not observed until after 70 trials. In contrast, results showed a greater change in reaches after a limited number of reach training trials with the rotated cursor. These findings suggest that proprioceptive recalibration arises more slowly than reach adaptation. PMID:27014777

  18. Neurocytoma arising from a mature ovary teratoma: a case report.

    PubMed

    Yu, Juan-Han; Yang, Lian-He; Lin, Xu-Yong; Dai, Shun-Dong; Qiu, Xue-Shan; Wang, En-Hua

    2015-01-01

    Central neurocytoma/extraventricular neurocytoma is a central nervous system (CNS) tumor composed of uniform round cells with neuronal differentiation. The typical lesions of central neurocytoma/extraventricular neurocytoma are at the interventricular foramen of the lateral ventricles (central neurocytoma) or brain parenchyma (extraventricular neurocytoma). Mature teratoma is a benign germ cell tumor commonly found in young women. Herein, we report a 24-year-old female with neurocytoma in a mature teratoma of the right ovary. The histological examinations showed mature epidermis, skin appendages, adipose and bone tissues in the tumor; microscopic foci of immature cartilage tissues were also found in some parts. In addition, massive solid sheets and uniform round tumor cells were found in the neuroectodermal tissues, with the formation of neuropil-like islands. Immunohistochemical examinations showed that the tumor cells were synaptophysin- and NeuN-positive but GFAP-negative. Based on these findings, the woman was diagnosed with neurocytoma arising from mature ovary teratoma, with microscopic foci of immature cartilage tissues. This is the fourth case report of neurocytoma outside the CNS to date. PMID:26376790

  19. Novel ethical dilemmas arising in geriatric clinical practice.

    PubMed

    Calleja-Sordo, Elisa Constanza; de Hoyos, Adalberto; Méndez-Jiménez, Jorge; Altamirano-Bustamante, Nelly F; Islas-Andrade, Sergio; Valderrama, Alejandro; García-Peña, Carmen; Altamirano-Bustamante, Myriam M

    2015-05-01

    The purpose of this study is to determine empirically the state of the art of the medical care, when healthcare personal is confronted with ethical dilemmas related with the care they give to the geriatric population. An observational, longitudinal, prospective and qualitative study was conducted by analyzing the correlation between healthcare personnel-patient relationship, and ethical judgments regarding dilemmas that arise in daily clinical practice with geriatric patients. Mexican healthcare personnel with current active practices were asked to write up an ethical dilemma that arose frequently or that had impacted their medical practice. From the narrative input, we were able to draw up a database with 421 dilemmas, and those corresponding to patients 60 years and older were selected (n = 54, 12.8 %). The axiological analysis of the narrative dilemmas of geriatric patients was made using dialectical empiricism. The axiological analysis values found most frequently were classified into three groups: the impact of healthcare, the roles of the physician, and refusal of therapy; the healthcare role of educator, caring for the patients' life and the risk of imminent death where the values found more often. The persistence and universality of certain dilemmas in geriatrics calls for awareness and requires a good training in the ethical discernment of these dilemmas. This would help to improve substantially the care and the life quality of this population. PMID:25185872

  20. Contribution to irradiation creep arising from gas-driven bubbles

    SciTech Connect

    Woo, C.H.; Garner, F.A.

    1998-03-01

    In a previous paper the relationship was defined between void swelling and irradiation creep arising from the interaction of the SIPA and SIG creep-driven deformation and swelling-driven deformation was highly interactive in nature, and that the two contributions could not be independently calculated and then considered as directly additive. This model could be used to explain the recent experimental observation that the creep-swelling coupling coefficient was not a constant as previously assumed, but declined continuously as the swelling rate increased. Such a model thereby explained the creep-disappearance and creep-damping anomalies observed in conditions where significant void swelling occurred before substantial creep deformation developed. At lower irradiation temperatures and high helium/hydrogen generation rates, such as found in light water cooled reactors and some fusion concepts, gas-filled cavities that have not yet exceeded the critical radius for bubble-void conversion should also exert an influence on irradiation creep. In this paper the original concept is adapted to include such conditions, and its predictions then compared with available data. It is shown that a measurable increase in the creep rate is expected compared to the rate found in low gas-generating environments. The creep rate is directly related to the gas generation rate and thereby to the neutron flux and spectrum.

  1. Dioxins: diagnostic and prognostic challenges arising from complex mechanisms.

    PubMed

    Rysavy, Noel M; Maaetoft-Udsen, Kristina; Turner, Helen

    2013-01-01

    Dioxins are ubiquitous environmental challenges to humans, with a pervasiveness that arises from 200 years of rapid industrialization and mechanization of Western societies and which is now extending into the developing world. In spite of their penetrance of the human biota, these compounds are poorly understood in terms of their true physiological potential for harm, and the mechanisms by which they impact cellular and organ level function are only recently becoming clear. Emerging awareness that chronic exposures to toxins may have generational and subtle effects on the outcomes of diseases such as cancer and diabetes, which are already multifactorial and highly complex, creates the context for the current review paper. Here, we summarize dioxin exposure paradigms and the resulting physiological effects that have been documented in animals and humans. Novel insights into potential endogenous end exogenous ligands, as well as the mechanisms by which these ligands impact acute and chronic cellular processes, are discussed. We develop the idea that the diagnosis of dioxin exposure, the subtleties of the cellular effects of the compounds and prognosis of the long-term effects of exposure are problems requiring that researchers leverage the power of genomics and epigenetics. However, the continuation of longitudinal epidemiological studies and the development of a firmer basis from which to extrapolate animal studies will be critical in ensuring optimal insight from these resource-intensive techniques. PMID:22610997

  2. Risk analysis for renewable energy projects due to constraints arising

    NASA Astrophysics Data System (ADS)

    Prostean, G.; Vasar, C.; Prostean, O.; Vartosu, A.

    2016-02-01

    Starting from the target of the European Union (EU) to use renewable energy in the area that aims a binding target of 20% renewable energy in final energy consumption by 2020, this article illustrates the identification of risks for implementation of wind energy projects in Romania, which could lead to complex technical implications, social and administrative. In specific projects analyzed in this paper were identified critical bottlenecks in the future wind power supply chain and reasonable time periods that may arise. Renewable energy technologies have to face a number of constraints that delayed scaling-up their production process, their transport process, the equipment reliability, etc. so implementing these types of projects requiring complex specialized team, the coordination of which also involve specific risks. The research team applied an analytical risk approach to identify major risks encountered within a wind farm project developed in Romania in isolated regions with different particularities, configured for different geographical areas (hill and mountain locations in Romania). Identification of major risks was based on the conceptual model set up for the entire project implementation process. Throughout this conceptual model there were identified specific constraints of such process. Integration risks were examined by an empirical study based on the method HAZOP (Hazard and Operability). The discussion describes the analysis of our results implementation context of renewable energy projects in Romania and creates a framework for assessing energy supply to any entity from renewable sources.

  3. Dioxins: diagnostic and prognostic challenges arising from complex mechanisms

    PubMed Central

    Rysavy, Noel M.; Maaetoft-Udsen, Kristina; Turner, Helen

    2013-01-01

    Dioxins are ubiquitous environmental challenges to humans, with a pervasiveness that arises from two hundred years of rapid industrialization and mechanization of Western societies and which is now extending into the developing world. Despite their penetrance of the human biota, these compounds are poorly understood in terms of their true physiological potential for harm, and the mechanisms by which they impact cellular and organ level function are only recently becoming clear. Emerging awareness that chronic exposures to toxins may have generational and subtle effects on the outcomes of diseases such as cancer and diabetes, which are already multifactorial and highly complex, creates the context for the current review paper. Here, we summarize dioxin exposure paradigms and the resulting physiological effects that have been documented in animals and humans. Novel insights into potential endogenous end exogenous ligands, as well as the mechanisms by which these ligands impact acute and chronic cellular processes, are discussed. We develop the idea that the diagnosis of dioxin exposure, the subtleties of the cellular effects of the compounds and prognosis of the long term effects of exposure are problems requiring that researchers leverage the power of genomics and epigenetics. However, the continuation of longitudinal epidemiological studies and development of a firmer basis from which to extrapolate animal studies will be critical in ensuring optimal insight from these resource-intensive techniques. PMID:22610997

  4. Impedance control reduces instability that arises from motor noise

    PubMed Central

    Selen, Luc P.J.; Franklin, David W.; Wolpert, Daniel M.

    2009-01-01

    There is ample evidence that humans are able to control the endpoint impedance of their arms in response to active destabilizing force fields. However, such fields are uncommon in daily life. Here, we examine whether the CNS selectively controls the arm’s endpoint impedance in the absence of active force fields but in the presence of instability arising from task geometry and signal-dependent noise in the neuromuscular system. Subjects were required to generate forces, in two orthogonal directions, onto four differently curved rigid objects simulated by a robotic manipulandum. The endpoint stiffness of the limb was estimated for each object curvature. With increasing curvature, the endpoint stiffness increased mainly parallel to the object surface, and to a lesser extent in the orthogonal direction. Therefore, the orientation of the stiffness ellipses did not orient to the direction of instability. Simulations showed that the observed stiffness geometries and their pattern of change with instability are the result of a trade-off between maximizing the mechanical stability and minimizing the destabilizing effects of signal-dependent noise. Therefore, it would have been sub-optimal to align the stiffness ellipse in the direction of instability. The time course of the changes in stiffness geometry suggests that modulation takes place both within and across trials. Our results show that an increase in stiffness relative to the increase in noise can be sufficient to reduce kinematic variability, thereby allowing stiffness control to improve stability in natural tasks. PMID:19812335

  5. Giant lipoma arising from deep lobe of the parotid gland

    PubMed Central

    Wu, Che-Wei; Chi, Hung-Pin; Chiang, Feng-Yu; Hsu, Ying-Che; Chan, Leong-Perng; Kuo, Wen-Rei

    2006-01-01

    Background Lipomas are common benign soft tissue neoplasms but they are found very rarely in the deep lobe of parotid gland. Surgical intervention in these tumors is challenging because of the proximity of the facial nerve, and thus knowledge of the anatomy and meticulous surgical technique are essential. Case presentation A 71-year-old female presented with a large asymptomatic mass, which had occupied the left facial area for over the past fifteen years, and she requested surgical excision for a cosmetically better facial appearance. The computed tomography (CT) scan showed a well-defined giant lipoma arising from the left deep parotid gland. The lipoma was successfully enucleated after full exposure and mobilization of the overlying facial nerve branches. The surgical specimen measured 9 × 6 cm in size, and histopathology revealed fibrolipoma. The patient experienced an uneventful recovery, with a satisfying facial contour and intact facial nerve function. Conclusion Giant lipomas involving the deep parotid lobe are extremely rare. The high-resolution CT scan provides an accurate and cost-effective preoperative investigative method. Surgical management of deep lobe lipoma should be performed by experienced surgeons due to the need for meticulous dissection of the facial nerve branches. Superficial parotidectomy before deep lobe lipoma removal may be unnecessary in selected cases because preservation of the superficial lobe may contribute to a better aesthetic and functional result. PMID:16740172

  6. Cribriform neuroepithelial tumor arising in the lateral ventricle.

    PubMed

    Arnold, Michael A; Stallings-Archer, Kandi; Marlin, Evan; Grondin, Ronald; Olshefski, Randal; Biegel, Jaclyn A; Pierson, Christopher R

    2013-01-01

    Cribriform neuroepithelial tumor (CRINET) is a recently recognized central nervous system neoplasm that arises in the ventricles of young children and is characterized by primitive, non-rhabdoid SMARCB1-deficient cells with prominent cribriform architecture. We report a 14-month-old male who presented with signs of increased intracranial pressure. Neuroimaging revealed a large solid and cystic mass in the lateral ventricle. Tumor cells were small, primitive appearing, and arranged in cribriform and trabecular patterns with interspersed solid cellular areas. Rhabdoid cells were absent. Immunohistochemical staining showed no SMARCB1 (INI11, BAF47, hSNF5) expression and strong epithelial membrane antigen (EMA) immunoreactivity along luminal surfaces. Electron microscopy showed epithelial characteristics, including abundant basal lamina. Genetic analysis of the tumor revealed deletion of 1 SMARCB1 allele, while the other contained an intronic point mutation predicted to disrupt splicing. This case further illustrates the distinct histopathologic and molecular genetic features of CRINET and identifies distinctive ultrastructural features. PMID:23495723

  7. On Bounded Posets Arising from Quantum Mechanical Measurements

    NASA Astrophysics Data System (ADS)

    Dorninger, Dietmar; Länger, Helmut

    2016-06-01

    Let S be a set of states of a physical system. The probabilities p(s) of the occurrence of an event when the system is in different states s ∈ S define a function from S to [0, 1] called a numerical event or, more precisely, an S-probability. If one orders a set P of S-probabilities in respect to the order of functions, further includes the constant functions 0 and 1 and defines p' = 1 - p for every p ∈ P, then one obtains a bounded poset of S-probabilities with an antitone involution. We study these posets in respect to various conditions about the existence of the sum of certain functions within the posets and derive properties from these conditions. In particular, questions of relations between different classes of S-probabilities arising this way are settled, algebraic representations are provided and the property that two S-probabilities commute is characterized which is essential for recognizing a classical physical system.

  8. Vibrotactile difference thresholds: effects of vibration frequency, vibration magnitude, contact area, and body location.

    PubMed

    Forta, Nazim Gizem; Griffin, Michael J; Morioka, Miyuki

    2012-01-01

    It has not been established whether the smallest perceptible change in the intensity of vibrotactile stimuli depends on the somatosensory channel mediating the sensation. This study investigated intensity difference thresholds for vibration using contact conditions (different frequencies, magnitudes, contact areas, body locations) selected so that perception would be mediated by more than one psychophysical channel. It was hypothesized that difference thresholds mediated by the non-Pacinian I (NPI) channel and the Pacinian (P) channel would differ. Using two different contactors (1-mm diameter contactor with 1-mm gap to a fixed surround; 10-mm diameter contactor with 2-mm gap to the surround) vibration was applied to the thenar eminence and the volar forearm at two frequencies (10 and 125 Hz). The up-down-transformed-response method with a three-down-one-up rule provided absolute thresholds and also difference thresholds at various levels above the absolute thresholds of 12 subjects (i.e., sensation levels, SLs) selected to activate preferentially either single channels or multiple channels. Median difference thresholds varied from 0.20 (thenar eminence with 125-Hz vibration at 10 dB SL) to 0.58 (thenar eminence with 10-Hz vibration at 20 dB SL). Median difference thresholds tended to be lower for the P channel than the NPI channel. The NPII channel may have reduced difference thresholds with the smaller contactor at 125 Hz. It is concluded that there are large and systematic variations in difference thresholds associated with the frequency, the magnitude, the area of contact, and the location of contact with vibrotactile stimuli that cannot be explained without increased understanding of the perception of supra-threshold vibrotactile stimuli. PMID:22416802

  9. These lit areas are undeveloped: Delimiting China's urban extents from thresholded nighttime light imagery

    NASA Astrophysics Data System (ADS)

    Liu, Ying; Delahunty, Tina; Zhao, Naizhuo; Cao, Guofeng

    2016-08-01

    Nighttime light imagery is a powerful tool to study urbanization because it can provide a uniform metric, lit area, to delimit urban extents. However, lit area is much larger than actual urban area, so thresholds of digital number (DN) values are usually needed to reduce the lit area. The threshold varies greatly among different regions, but at present it is still not very clear what factors impact the changes of the threshold. In this study, urban extent by province for China is mapped using official statistical data and four intercalibrated and geometrically corrected nighttime light images between 2004 and 2010. Lit area in the imagery for most provinces is at least 94% greater than the official amount of urban area. Regression analyses show a significant correlation between optimal thresholds and GDP per capita, and larger thresholds more commonly indicate higher economic level. Size and environmental condition may explain a province's threshold that is disproportionate to GDP. Findings indicate one threshold DN is not appropriate for multiple (adjacent) province urban extent mapping, and optimal thresholds for one year may be notably different than the next. Province-level derived thresholds are not appropriate for other geographic levels. Brightness of nighttime lights is an advantage over imagery that relies on daylight reflection, and decreases in brightness indicate faster growth in the horizontal direction than the vertical. A province's optimal threshold does not always maintain an increase with population and economic growth. In the economically developed eastern provinces, urban population densities decreased (and this is seen in the brightness data), while urban population increased.

  10. 40 CFR 98.281 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Silicon Carbide Production § 98.281 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a silicon carbide production process...

  11. 40 CFR 98.281 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Silicon Carbide Production § 98.281 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a silicon carbide production process...

  12. 40 CFR 98.281 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Silicon Carbide Production § 98.281 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a silicon carbide production process...

  13. 40 CFR 98.281 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Silicon Carbide Production § 98.281 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a silicon carbide production process...

  14. 40 CFR 98.281 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Silicon Carbide Production § 98.281 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a silicon carbide production process...

  15. 40 CFR 98.141 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.141 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a glass production process and the facility meets...

  16. 40 CFR 98.141 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.141 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a glass production process and the facility meets...

  17. 40 CFR 98.141 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.141 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a glass production process and the facility meets...

  18. 40 CFR 98.141 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.141 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a glass production process and the facility meets...

  19. 40 CFR 98.141 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Glass Production § 98.141 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a glass production process and the facility meets...

  20. Error Threshold of Fully Random Eigen Model

    NASA Astrophysics Data System (ADS)

    Li, Duo-Fang; Cao, Tian-Guang; Geng, Jin-Peng; Qiao, Li-Hua; Gu, Jian-Zhong; Zhan, Yong

    2015-01-01

    Species evolution is essentially a random process of interaction between biological populations and their environments. As a result, some physical parameters in evolution models are subject to statistical fluctuations. In this work, two important parameters in the Eigen model, the fitness and mutation rate, are treated as Gaussian distributed random variables simultaneously to examine the property of the error threshold. Numerical simulation results show that the error threshold in the fully random model appears as a crossover region instead of a phase transition point, and as the fluctuation strength increases the crossover region becomes smoother and smoother. Furthermore, it is shown that the randomization of the mutation rate plays a dominant role in changing the error threshold in the fully random model, which is consistent with the existing experimental data. The implication of the threshold change due to the randomization for antiviral strategies is discussed.

  1. Threshold altitude resulting in decompression sickness

    NASA Technical Reports Server (NTRS)

    Kumar, K. V.; Waligora, James M.; Calkins, Dick S.

    1990-01-01

    A review of case reports, hypobaric chamber training data, and experimental evidence indicated that the threshold for incidence of altitude decompression sickness (DCS) was influenced by various factors such as prior denitrogenation, exercise or rest, and period of exposure, in addition to individual susceptibility. Fitting these data with appropriate statistical models makes it possible to examine the influence of various factors on the threshold for DCS. This approach was illustrated by logistic regression analysis on the incidence of DCS below 9144 m. Estimations using these regressions showed that, under a noprebreathe, 6-h exposure, simulated EVA profile, the threshold for symptoms occurred at approximately 3353 m; while under a noprebreathe, 2-h exposure profile with knee-bends exercise, the threshold occurred at 7925 m.

  2. 40 CFR 98.411 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.411 Reporting threshold. Any supplier of industrial greenhouse gases who meets the requirements of § 98.2(a)(4) must report...

  3. 40 CFR 98.411 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.411 Reporting threshold. Any supplier of industrial greenhouse gases who meets the requirements of § 98.2(a)(4) must report...

  4. 40 CFR 98.411 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.411 Reporting threshold. Any supplier of industrial greenhouse gases who meets the requirements of § 98.2(a)(4) must report...

  5. 40 CFR 98.411 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.411 Reporting threshold. Any supplier of industrial greenhouse gases who meets the requirements of § 98.2(a)(4) must report...

  6. 40 CFR 98.411 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Industrial Greenhouse Gases § 98.411 Reporting threshold. Any supplier of industrial greenhouse gases who meets the requirements of § 98.2(a)(4) must report...

  7. 40 CFR 98.41 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.41 Reporting threshold. You must report GHG emissions under this subpart if your facility contains one or more electricity generating units and...

  8. 40 CFR 98.41 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.41 Reporting threshold. You must report GHG emissions under this subpart if your facility contains one or more electricity generating units and...

  9. 40 CFR 98.331 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Zinc Production § 98.331 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a zinc production process and the facility meets...

  10. 40 CFR 98.331 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Zinc Production § 98.331 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a zinc production process and the facility meets...

  11. 40 CFR 98.331 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Zinc Production § 98.331 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a zinc production process and the facility meets...

  12. 40 CFR 98.331 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Zinc Production § 98.331 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a zinc production process and the facility meets...

  13. 40 CFR 98.331 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Zinc Production § 98.331 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a zinc production process and the facility meets...

  14. 40 CFR 98.341 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Municipal Solid Waste Landfills § 98.341 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a MSW landfill and the facility...

  15. Nonlinear theory of kinetic instabilities near threshold

    SciTech Connect

    Berk, H.L.; Pekker, M.S.; Breizman, B.N. |

    1997-05-01

    A new nonlinear equation has been derived and solved for the evolution of an unstable collective mode in a kinetic system close to the threshold of linear instability. The resonant particle response produces the dominant nonlinearity, which can be calculated iteratively in the near-threshold regime as long as the mode doe snot trap resonant particles. With sources and classical relaxation processes included, the theory describes both soft nonlinear regimes, where the mode saturation level is proportional to an increment above threshold, and explosive nonlinear regimes, where the mode grows to a level that is independent of the closeness to threshold. The explosive solutions exhibit mode frequency shifting. For modes that exist in the absence of energetic particles, the frequency shift is both upward and downward. For modes that require energetic particles for their existence, there is a preferred direction of the frequency shift. The frequency shift continues even after the mode traps resonant particles.

  16. Laser damage threshold of diamond films

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia; Cropper, Andre D.; Watkins, Linwood C.; Byvik, Charles E.; Buoncristiani, A. Martin

    1989-01-01

    The possibility that diamond films may inhibit laser-induced damage to optical components in laser systems films was investigated by measuring laser damage thresholds of free-standing diamond film windows, diamond films deposited on silicon substrates, and bare silicon substrate. Polycrystalline diamond films were deposited using a dc plasma-enhanced CVD process. It was found that free-standing diamond films had the highest laser damage threshold at 1064 nm. For a diamond film of 630 nm, the damage threshold was found to be 7 J/sq cm, as compared to a damage threshold of 4.5 J/sq cm for bare silicon, and a low value of 1.5 J/sq cm for the film/substrate combination. The damage mechanism is considered to involve melting or dielectric breakdown induced by laser radiation. The low value of the film/substrate combination is attributed to film stress and conditions of film deposition.

  17. 40 CFR 98.291 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Soda Ash Manufacturing § 98.291 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a soda ash manufacturing process and the...

  18. 40 CFR 98.261 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.261 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a phosphoric acid production process...

  19. 40 CFR 98.261 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.261 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a phosphoric acid production process...

  20. 40 CFR 98.261 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.261 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a phosphoric acid production process...

  1. 40 CFR 98.261 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.261 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a phosphoric acid production process...

  2. 40 CFR 98.261 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Phosphoric Acid Production § 98.261 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a phosphoric acid production process...

  3. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.81 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a cement production process and the facility...

  4. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Cement Production § 98.81 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a cement production process and the facility...

  5. 40 CFR 98.61 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.61 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an aluminum production process and the facility...

  6. 40 CFR 98.61 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.61 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an aluminum production process and the facility...

  7. 40 CFR 98.61 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.61 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an aluminum production process and the facility...

  8. 40 CFR 98.61 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.61 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an aluminum production process and the facility...

  9. 40 CFR 98.61 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Aluminum Production § 98.61 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an aluminum production process and the facility...

  10. Laser damage threshold of diamond films

    NASA Astrophysics Data System (ADS)

    Albin, Sacharia; Cropper, Andre D.; Watkins, Linwood C.; Byvik, Charles E.; Buoncristiani, A. Martin

    1989-03-01

    The possibility that diamond films may inhibit laser-induced damage to optical components in laser systems films was investigated by measuring laser damage thresholds of free-standing diamond film windows, diamond films deposited on silicon substrates, and bare silicon substrate. Polycrystalline diamond films were deposited using a dc plasma-enhanced CVD process. It was found that free-standing diamond films had the highest laser damage threshold at 1064 nm. For a diamond film of 630 nm, the damage threshold was found to be 7 J/sq cm, as compared to a damage threshold of 4.5 J/sq cm for bare silicon, and a low value of 1.5 J/sq cm for the film/substrate combination. The damage mechanism is considered to involve melting or dielectric breakdown induced by laser radiation. The low value of the film/substrate combination is attributed to film stress and conditions of film deposition.

  11. 40 CFR 98.41 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.41 Reporting threshold. You must report GHG emissions under this subpart if your facility contains one or more electricity generating units and...

  12. 40 CFR 98.41 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.41 Reporting threshold. You must report GHG emissions under this subpart if your facility contains one or more electricity generating units and...

  13. 40 CFR 98.41 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electricity Generation § 98.41 Reporting threshold. You must report GHG emissions under this subpart if your facility contains one or more electricity generating units and...

  14. 40 CFR 98.31 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.31 Reporting threshold... combustion sources and the facility meets the applicability requirements of either § 98.2(a)(1), §...

  15. 40 CFR 98.401 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Natural Gas and Natural Gas Liquids § 98.401 Reporting threshold. Any supplier of natural gas and natural gas liquids that meets the requirements of §...

  16. 40 CFR 98.161 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.161 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a hydrogen production process and the facility...

  17. 40 CFR 98.161 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.161 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a hydrogen production process and the facility...

  18. 40 CFR 98.161 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.161 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a hydrogen production process and the facility...

  19. 40 CFR 98.161 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.161 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a hydrogen production process and the facility...

  20. 40 CFR 98.71 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.71 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an ammonia manufacturing process and the...

  1. 40 CFR 98.71 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.71 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an ammonia manufacturing process and the...

  2. 40 CFR 98.71 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.71 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an ammonia manufacturing process and the...

  3. 40 CFR 98.71 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.71 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an ammonia manufacturing process and the...

  4. 40 CFR 98.71 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ammonia Manufacturing § 98.71 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an ammonia manufacturing process and the...

  5. 40 CFR 98.401 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Natural Gas and Natural Gas Liquids § 98.401 Reporting threshold. Any supplier of natural gas and natural gas liquids that meets the requirements of §...

  6. 40 CFR 98.401 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Natural Gas and Natural Gas Liquids § 98.401 Reporting threshold. Any supplier of natural gas and natural gas liquids that meets the requirements of §...

  7. 40 CFR 98.401 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Natural Gas and Natural Gas Liquids § 98.401 Reporting threshold. Any supplier of natural gas and natural gas liquids that meets the requirements of §...

  8. 40 CFR 98.401 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Natural Gas and Natural Gas Liquids § 98.401 Reporting threshold. Any supplier of natural gas and natural gas liquids that meets the requirements of §...

  9. 40 CFR 98.321 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.321 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an active underground coal mine and the...

  10. 40 CFR 98.381 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.381 Reporting threshold. Any supplier of coal-to-liquid products who meets the requirements of § 98.2(a)(4) must report GHG emissions....

  11. 40 CFR 98.321 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.321 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an active underground coal mine and the...

  12. 40 CFR 98.381 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.381 Reporting threshold. Any supplier of coal-to-liquid products who meets the requirements of § 98.2(a)(4) must report GHG emissions....

  13. 40 CFR 98.381 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.381 Reporting threshold. Any supplier of coal-to-liquid products who meets the requirements of § 98.2(a)(4) must report GHG emissions....

  14. 40 CFR 98.381 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.381 Reporting threshold. Any supplier of coal-to-liquid products who meets the requirements of § 98.2(a)(4) must report GHG emissions....

  15. 40 CFR 98.381 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Coal-based Liquid Fuels § 98.381 Reporting threshold. Any supplier of coal-to-liquid products who meets the requirements of § 98.2(a)(4) must report GHG emissions....

  16. 40 CFR 98.321 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.321 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an active underground coal mine and the...

  17. 40 CFR 98.321 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Underground Coal Mines § 98.321 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an active underground coal mine and the...

  18. 40 CFR 98.161 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Hydrogen Production § 98.161 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a hydrogen production process and the facility...

  19. 40 CFR 98.171 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Iron and Steel Production § 98.171 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an iron and steel production process...

  20. 40 CFR 98.171 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Iron and Steel Production § 98.171 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an iron and steel production process...

  1. 40 CFR 98.201 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.201 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a magnesium production process and the facility...

  2. 40 CFR 98.201 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.201 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a magnesium production process and the facility...

  3. 40 CFR 98.201 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.201 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a magnesium production process and the facility...

  4. 40 CFR 98.201 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Magnesium Production § 98.201 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a magnesium production process and the facility...

  5. 40 CFR 98.311 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Titanium Dioxide Production § 98.311 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a titanium dioxide production process...

  6. 40 CFR 98.311 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Titanium Dioxide Production § 98.311 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a titanium dioxide production process...

  7. 40 CFR 98.311 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Titanium Dioxide Production § 98.311 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a titanium dioxide production process...

  8. 40 CFR 98.311 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Titanium Dioxide Production § 98.311 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a titanium dioxide production process...

  9. 40 CFR 98.311 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Titanium Dioxide Production § 98.311 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a titanium dioxide production process...

  10. 40 CFR 98.221 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.221 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a nitric acid train and the facility meets...

  11. Photocurrent multiplication in organic single crystals

    NASA Astrophysics Data System (ADS)

    Hiramoto, Masahiro; Miki, Ayako; Yoshida, Manabu; Yokoyama, Masaaki

    2002-08-01

    A photocurrent multiplication of up to 200 times has been observed in single crystals of naphthalene tetracarboxylic anhydride sandwiched between metal electrodes. Photocurrent multiplication arises from photoinduced electron injection occurring at the crystal/metal interface. The high-speed response of the multiplied photocurrent reached 500 ms.

  12. Vanishing of {1}/{m} corrections at threshold

    NASA Astrophysics Data System (ADS)

    Boyd, C. Glenn; Brahm, David E.

    1991-03-01

    Heavy-quark predictions for hadronic weak-decay transition amplitudes have O( {1}/{m}) corrections, but we show these always vanish at threshold. This follows from the nonrenormalization of the threshold effective currents at O( {1}/{m}) , and an application of the Ademollo-Gatto theorem. The result, which we call Luke's theorem, holds for initial and final particles consisting of a heavy quark or scalar and light degrees of freedom in an arbitrary spin state.

  13. Optimizing Retransmission Threshold in Wireless Sensor Networks.

    PubMed

    Bi, Ran; Li, Yingshu; Tan, Guozhen; Sun, Liang

    2016-01-01

    The retransmission threshold in wireless sensor networks is critical to the latency of data delivery in the networks. However, existing works on data transmission in sensor networks did not consider the optimization of the retransmission threshold, and they simply set the same retransmission threshold for all sensor nodes in advance. The method did not take link quality and delay requirement into account, which decreases the probability of a packet passing its delivery path within a given deadline. This paper investigates the problem of finding optimal retransmission thresholds for relay nodes along a delivery path in a sensor network. The object of optimizing retransmission thresholds is to maximize the summation of the probability of the packet being successfully delivered to the next relay node or destination node in time. A dynamic programming-based distributed algorithm for finding optimal retransmission thresholds for relay nodes along a delivery path in the sensor network is proposed. The time complexity is O n Δ · max 1 ≤ i ≤ n { u i } , where u i is the given upper bound of the retransmission threshold of sensor node i in a given delivery path, n is the length of the delivery path and Δ is the given upper bound of the transmission delay of the delivery path. If Δ is greater than the polynomial, to reduce the time complexity, a linear programming-based ( 1 + p m i n ) -approximation algorithm is proposed. Furthermore, when the ranges of the upper and lower bounds of retransmission thresholds are big enough, a Lagrange multiplier-based distributed O ( 1 ) -approximation algorithm with time complexity O ( 1 ) is proposed. Experimental results show that the proposed algorithms have better performance. PMID:27171092

  14. Flicker fusion thresholds in Best macular dystrophy.

    PubMed

    Massof, R W; Fleischman, J A; Fine, S L; Yoder, F

    1977-06-01

    Flicker fusion threshold intensities were measured as a function of flicker frequency for patients with Best macular dystrophy having normal or near-normal Snellen visual acuity. These data were found to differ from normal in ways that may be interpreted to be an abnormal elevation of the foveal cone threshold, a loss of cone temporal resolution, or both. The results led to the conclusion that Best macular dystrophy affects the neurosensory retina even when Snellen visual acuity is normal. PMID:869758

  15. Optimizing Retransmission Threshold in Wireless Sensor Networks

    PubMed Central

    Bi, Ran; Li, Yingshu; Tan, Guozhen; Sun, Liang

    2016-01-01

    The retransmission threshold in wireless sensor networks is critical to the latency of data delivery in the networks. However, existing works on data transmission in sensor networks did not consider the optimization of the retransmission threshold, and they simply set the same retransmission threshold for all sensor nodes in advance. The method did not take link quality and delay requirement into account, which decreases the probability of a packet passing its delivery path within a given deadline. This paper investigates the problem of finding optimal retransmission thresholds for relay nodes along a delivery path in a sensor network. The object of optimizing retransmission thresholds is to maximize the summation of the probability of the packet being successfully delivered to the next relay node or destination node in time. A dynamic programming-based distributed algorithm for finding optimal retransmission thresholds for relay nodes along a delivery path in the sensor network is proposed. The time complexity is OnΔ·max1≤i≤n{ui}, where ui is the given upper bound of the retransmission threshold of sensor node i in a given delivery path, n is the length of the delivery path and Δ is the given upper bound of the transmission delay of the delivery path. If Δ is greater than the polynomial, to reduce the time complexity, a linear programming-based (1+pmin)-approximation algorithm is proposed. Furthermore, when the ranges of the upper and lower bounds of retransmission thresholds are big enough, a Lagrange multiplier-based distributed O(1)-approximation algorithm with time complexity O(1) is proposed. Experimental results show that the proposed algorithms have better performance. PMID:27171092

  16. Optical spectral singularities as threshold resonances

    SciTech Connect

    Mostafazadeh, Ali

    2011-04-15

    Spectral singularities are among generic mathematical features of complex scattering potentials. Physically they correspond to scattering states that behave like zero-width resonances. For a simple optical system, we show that a spectral singularity appears whenever the gain coefficient coincides with its threshold value and other parameters of the system are selected properly. We explore a concrete realization of spectral singularities for a typical semiconductor gain medium and propose a method of constructing a tunable laser that operates at threshold gain.

  17. Initiation Pressure Thresholds from Three Sources

    SciTech Connect

    Souers, P C; Vitello, P

    2007-02-28

    Pressure thresholds are minimum pressures needed to start explosive initiation that ends in detonation. We obtain pressure thresholds from three sources. Run-to-detonation times are the poorest source but the fitting of a function gives rough results. Flyer-induced initiation gives the best results because the initial conditions are the best known. However, very thick flyers are needed to give the lowest, asymptotic pressure thresholds used in modern models and this kind of data is rarely available. Gap test data is in much larger supply but the various test sizes and materials are confusing. We find that explosive pressures are almost the same if the distance in the gap test spacers are in units of donor explosive radius. Calculated half-width time pulses in the spacers may be used to create a pressure-time curve similar to that of the flyers. The very-large Eglin gap tests give asymptotic thresholds comparable to extrapolated flyer results. The three sources are assembled into a much-expanded set of near-asymptotic pressure thresholds. These thresholds vary greatly with density: for TATB/LX-17/PBX 9502, we find values of 4.9 and 8.7 GPa at 1.80 and 1.90 g/cm{sup 3}, respectively.

  18. Quantitative mammography contrast threshold test tool.

    PubMed

    Wagner, A J; Frey, G D

    1995-02-01

    Mammographic contrast is commonly evaluated by visualizing small objects of varying size or mass divided by projected area. These qualitative contrast determinations are commonly performed by imaging a phantom like the American College of Radiology accreditation phantom at clinical mammographic settings. However, this contrast assessment does not take into account the kVp of the machine. This work describes a quantitative mammography contrast threshold test tool which examines light object contrast on a uniform background for a contrast range of 0.32% to 1.38% at 25 kVp. For this mammography contrast threshold test tool, contrast is defined by delta I/I = loge (psi O/ psi b), where psi O is the target energy flux, and psi b is the background energy flux. Contrast threshold is defined as the lowest contrast value for which the objects are visible. Unlike traditional assessments of mammographic contrast, this measurement of contrast threshold is kVp corrected. The mammography contrast threshold test tool is constructed out of common plastics and provides a quantitative means of assessing contrast threshold for individual mammographic units and total mammographic systems. PMID:7565343

  19. Threshold cascades with response heterogeneity in multiplex networks

    NASA Astrophysics Data System (ADS)

    Lee, Kyu-Min; Brummitt, Charles D.; Goh, K.-I.

    2014-12-01

    Threshold cascade models have been used to describe the spread of behavior in social networks and cascades of default in financial networks. In some cases, these networks may have multiple kinds of interactions, such as distinct types of social ties or distinct types of financial liabilities; furthermore, nodes may respond in different ways to influence from their neighbors of multiple types. To start to capture such settings in a stylized way, we generalize a threshold cascade model to a multiplex network in which nodes follow one of two response rules: some nodes activate when, in at least one layer, a large enough fraction of neighbors is active, while the other nodes activate when, in all layers, a large enough fraction of neighbors is active. Varying the fractions of nodes following either rule facilitates or inhibits cascades. Near the inhibition regime, global cascades appear discontinuously as the network density increases; however, the cascade grows more slowly over time. This behavior suggests a way in which various collective phenomena in the real world could appear abruptly yet slowly.

  20. Naturally arising tumors of the inbred WAB/Not rat strain. II. Immunogenicity of transplanted tumors

    SciTech Connect

    Middle, J.G.; Embleton, M.J.

    1981-09-01

    The immunogenicity of 28 transplanted naturally arising tumors of the inbred WAB/Not rat was investigated at early passages in strictly syngeneic, contemporary animals. Included were nephroblastomas, histologically benign and malignant mammary tumors, soft tissue and skin tumors, 1 lymphoid tumor, and 2 gastrointestinal lesions. In no case was evidence of immunogenicity observed when animals were treated with multiple grafts of irradiated (15,000 rad) tissue or by excision of a growing tumor. A few of these tumors were further investigated by other methods of immunization, including injection at various sites of irradiated cells followed by challenge at different sites and multiple injections of mitomycin C- or Formalin-treated cells. Again no evidence of immunogenicity was seen. Attempts to immunize with viable cells mixed with BCG or Corynebacterium parvum failed due to lack of tumor suppression by these agents. Limited concomitant immunity experiments yielded similarly negative results, except in one case of a fibrosarcoma for which a slight reduction in second tumor growth was observed when primary implants were very large. Some alterations in biologic properties during transplant passage and the incidence of postexcision recurrence and metastatic spread of some of the tumors are described.

  1. Polyclonal breast cancer metastases arise from collective dissemination of keratin 14-expressing tumor cell clusters.

    PubMed

    Cheung, Kevin J; Padmanaban, Veena; Silvestri, Vanesa; Schipper, Koen; Cohen, Joshua D; Fairchild, Amanda N; Gorin, Michael A; Verdone, James E; Pienta, Kenneth J; Bader, Joel S; Ewald, Andrew J

    2016-02-16

    Recent genomic studies challenge the conventional model that each metastasis must arise from a single tumor cell and instead reveal that metastases can be composed of multiple genetically distinct clones. These intriguing observations raise the question: How do polyclonal metastases emerge from the primary tumor? In this study, we used multicolor lineage tracing to demonstrate that polyclonal seeding by cell clusters is a frequent mechanism in a common mouse model of breast cancer, accounting for >90% of metastases. We directly observed multicolored tumor cell clusters across major stages of metastasis, including collective invasion, local dissemination, intravascular emboli, circulating tumor cell clusters, and micrometastases. Experimentally aggregating tumor cells into clusters induced a >15-fold increase in colony formation ex vivo and a >100-fold increase in metastasis formation in vivo. Intriguingly, locally disseminated clusters, circulating tumor cell clusters, and lung micrometastases frequently expressed the epithelial cytoskeletal protein, keratin 14 (K14). RNA-seq analysis revealed that K14(+) cells were enriched for desmosome and hemidesmosome adhesion complex genes, and were depleted for MHC class II genes. Depletion of K14 expression abrogated distant metastases and disrupted expression of multiple metastasis effectors, including Tenascin C (Tnc), Jagged1 (Jag1), and Epiregulin (Ereg). Taken together, our findings reveal K14 as a key regulator of metastasis and establish the concept that K14(+) epithelial tumor cell clusters disseminate collectively to colonize distant organs. PMID:26831077

  2. Polyclonal breast cancer metastases arise from collective dissemination of keratin 14-expressing tumor cell clusters

    PubMed Central

    Cheung, Kevin J.; Padmanaban, Veena; Silvestri, Vanesa; Schipper, Koen; Cohen, Joshua D.; Fairchild, Amanda N.; Gorin, Michael A.; Verdone, James E.; Pienta, Kenneth J.; Bader, Joel S.; Ewald, Andrew J.

    2016-01-01

    Recent genomic studies challenge the conventional model that each metastasis must arise from a single tumor cell and instead reveal that metastases can be composed of multiple genetically distinct clones. These intriguing observations raise the question: How do polyclonal metastases emerge from the primary tumor? In this study, we used multicolor lineage tracing to demonstrate that polyclonal seeding by cell clusters is a frequent mechanism in a common mouse model of breast cancer, accounting for >90% of metastases. We directly observed multicolored tumor cell clusters across major stages of metastasis, including collective invasion, local dissemination, intravascular emboli, circulating tumor cell clusters, and micrometastases. Experimentally aggregating tumor cells into clusters induced a >15-fold increase in colony formation ex vivo and a >100-fold increase in metastasis formation in vivo. Intriguingly, locally disseminated clusters, circulating tumor cell clusters, and lung micrometastases frequently expressed the epithelial cytoskeletal protein, keratin 14 (K14). RNA-seq analysis revealed that K14+ cells were enriched for desmosome and hemidesmosome adhesion complex genes, and were depleted for MHC class II genes. Depletion of K14 expression abrogated distant metastases and disrupted expression of multiple metastasis effectors, including Tenascin C (Tnc), Jagged1 (Jag1), and Epiregulin (Ereg). Taken together, our findings reveal K14 as a key regulator of metastasis and establish the concept that K14+ epithelial tumor cell clusters disseminate collectively to colonize distant organs. PMID:26831077

  3. Estimating Alarm Thresholds for Process Monitoring Data under Different Assumptions about the Data Generating Mechanism

    DOE PAGESBeta

    Burr, Tom; Hamada, Michael S.; Howell, John; Skurikhin, Misha; Ticknor, Larry; Weaver, Brian

    2013-01-01

    Process monitoring (PM) for nuclear safeguards sometimes requires estimation of thresholds corresponding to small false alarm rates. Threshold estimation dates to the 1920s with the Shewhart control chart; however, because possible new roles for PM are being evaluated in nuclear safeguards, it is timely to consider modern model selection options in the context of threshold estimation. One of the possible new PM roles involves PM residuals, where a residual is defined as residual = data − prediction. This paper reviews alarm threshold estimation, introduces model selection options, and considers a range of assumptions regarding the data-generating mechanism for PM residuals.more » Two PM examples from nuclear safeguards are included to motivate the need for alarm threshold estimation. The first example involves mixtures of probability distributions that arise in solution monitoring, which is a common type of PM. The second example involves periodic partial cleanout of in-process inventory, leading to challenging structure in the time series of PM residuals.« less

  4. Movement Timing and Invariance Arise from Several Geometries

    PubMed Central

    Bennequin, Daniel; Fuchs, Ronit; Berthoz, Alain; Flash, Tamar

    2009-01-01

    Human movements show several prominent features; movement duration is nearly independent of movement size (the isochrony principle), instantaneous speed depends on movement curvature (captured by the 2/3 power law), and complex movements are composed of simpler elements (movement compositionality). No existing theory can successfully account for all of these features, and the nature of the underlying motion primitives is still unknown. Also unknown is how the brain selects movement duration. Here we present a new theory of movement timing based on geometrical invariance. We propose that movement duration and compositionality arise from cooperation among Euclidian, equi-affine and full affine geometries. Each geometry posses a canonical measure of distance along curves, an invariant arc-length parameter. We suggest that for continuous movements, the actual movement duration reflects a particular tensorial mixture of these canonical parameters. Near geometrical singularities, specific combinations are selected to compensate for time expansion or compression in individual parameters. The theory was mathematically formulated using Cartan's moving frame method. Its predictions were tested on three data sets: drawings of elliptical curves, locomotion and drawing trajectories of complex figural forms (cloverleaves, lemniscates and limaçons, with varying ratios between the sizes of the large versus the small loops). Our theory accounted well for the kinematic and temporal features of these movements, in most cases better than the constrained Minimum Jerk model, even when taking into account the number of estimated free parameters. During both drawing and locomotion equi-affine geometry was the most dominant geometry, with affine geometry second most important during drawing; Euclidian geometry was second most important during locomotion. We further discuss the implications of this theory: the origin of the dominance of equi-affine geometry, the possibility that the brain

  5. Urban surface water pollution problems arising from misconnections.

    PubMed

    Revitt, D Michael; Ellis, J Bryan

    2016-05-01

    The impacts of misconnections on the organic and nutrient loadings to surface waters are assessed using specific household appliance data for two urban sub-catchments located in the London metropolitan region and the city of Swansea. Potential loadings of biochemical oxygen demand (BOD), soluble reactive phosphorus (PO4-P) and ammoniacal nitrogen (NH4-N) due to misconnections are calculated for three different scenarios based on the measured daily flows from specific appliances and either measured daily pollutant concentrations or average pollutant concentrations for relevant greywater and black water sources obtained from an extensive review of the literature. Downstream receiving water concentrations, together with the associated uncertainties, are predicted from derived misconnection discharge concentrations and compared to existing freshwater standards for comparable river types. Consideration of dilution ratios indicates that these would need to be of the order of 50-100:1 to maintain high water quality with respect to BOD and NH4-N following typical misconnection discharges but only poor quality for PO4-P is likely to be achievable. The main pollutant loading contributions to misconnections arise from toilets (NH4-N and BOD), kitchen sinks (BOD and PO4-P) washing machines (PO4-P and BOD) and, to a lesser extent, dishwashers (PO4-P). By completely eliminating toilet misconnections and ensuring misconnections from all other appliances do not exceed 2%, the potential pollution problems due to BOD and NH4-N discharges would be alleviated but this would not be the case for PO4-P. In the event of a treatment option being preferred to solve the misconnection problem, it is shown that for an area the size of metropolitan Greater London, a sewage treatment plant with a Population Equivalent value approaching 900,000 would be required to efficiently remove BOD and NH4-N to safely dischargeable levels but such a plant is unlikely to have the capacity to deal

  6. Classical Hodgkin Lymphoma Arising Adjacent to a Breast Implant.

    PubMed

    Ryan, Ciara; Ged, Yasser; Quinn, Fiona; Walker, Jan; Kennedy, John; Gillham, Charles; Pittaluga, Stefania; McDermott, Ronan; Vandenberghe, Elisabeth; Grant, Cliona; Flavin, Richard

    2016-08-01

    Breast implant-associated lymphoma has recently gained wide recognition. Anaplastic large cell lymphoma (ALCL) is the most frequently diagnosed subtype in this setting but the spectrum is broadening. A 66-year-old woman developed swelling and itch around her saline implant 6 years after its insertion. Imaging revealed a fluid collection surrounding the implant with an adjacent mass. Microscopy showed sclerotic tissue punctuated by discrete cellular nodules comprising small lymphocytes, eosinophils and interspersed large atypical Hodgkin Reed-Sternberg (HRS)-like cells. The HRS-like cells stained positively for CD30 and CD15 by immunohistochemistry. Small T-lymphocytes formed rosettes around HRS-like cells. Appearances were consistent with classical Hodgkin lymphoma (HL). Multiplex polymerase chain reaction demonstrated no clonal rearrangements of immunoglobulin or T-cell receptor genes, however, a t(14;18)(q32;q21)BCL2-JH translocation involving the major breakpoint region of the bcl2 gene was present. Staging positron emission tomography-computed tomography scan revealed FDG-avid masses in the right axilla and pelvis. Subsequent pathological examination identified low-grade follicular lymphoma (FL) with a t(14;18) translocation at these sites. To our knowledge, this is the first case of HL arising adjacent to a breast implant. An awareness of this diagnosis is important as classical HL, with its prominent mixed inflammatory background, may be overlooked as a reactive process when histologically assessing capsulectomy specimens. It is also important in the differential diagnosis for implant-associated ALCL as both contain large atypical CD30-positive cells highlighting the need for full immunohistochemical and molecular workup in such cases. This case also adds to the large body of literature regarding the association between HL and FL. PMID:26888955

  7. Special Issue featuring invited articles arising from UK Semiconductors 2012

    NASA Astrophysics Data System (ADS)

    Clarke, Edmund; Wada, Osamu

    2013-07-01

    Semiconductor research has formed the basis of many technological advances over the past 50 years, and the field is still highly active, as new material systems and device concepts are developed to address new applications or operating conditions. In addition to the development of traditional semiconductor devices, the wealth of experience with these materials also allows their use as an ideal environment for testing new physics, leading to new classes of devices exploiting quantum mechanical effects that can also benefit from the advantages of existing semiconductor technology in scalability, compactness and ease of mass production. This special issue features papers arising from the UK Semiconductors 2012 Conference, held at the University of Sheffield. The annual conference covers all aspects of semiconductor research, from crystal growth, through investigations of the physics of semiconductor structures to realization of semiconductor devices and their application in emerging technologies. The 2012 conference featured over 150 presentations, including plenary sessions on interband cascade lasers for the 3-6 µm spectral band, efficient single photon sources based on InAs quantum dots embedded in GaAs photonic nanowires, nitride-based quantum dot visible lasers and single photon sources, and engineering of organic light-emitting diodes. The seven papers collected here highlight current research advances, taken from across the scope of the conference. The papers feature growth of novel nitride-antimonide material systems for mid-infrared sources and detectors, use of semiconductor nanostructures for charge-based memory and visible lasers, optimization of device structures either to reduce losses in solar cells or achieve low noise amplification in transistors, design considerations for surface-emitting lasers incorporating photonic crystals and an assessment of laser power convertors for power transfer. The editors of this special issue and the conference

  8. No-threshold dose-response curves for nongenotoxic chemicals: Findings and applications for risk assessment

    SciTech Connect

    Sheehan, Daniel M. . E-mail: dansheeh@swbell.net

    2006-01-15

    We tested the hypothesis that no threshold exists when estradiol acts through the same mechanism as an active endogenous estrogen. A Michaelis-Menten (MM) equation accounting for response saturation, background effects, and endogenous estrogen level fit a turtle sex-reversal data set with no threshold and estimated the endogenous dose. Additionally, 31 diverse literature dose-response data sets were analyzed by adding a term for nonhormonal background; good fits were obtained but endogenous dose estimations were not significant due to low resolving power. No thresholds were observed. Data sets were plotted using a normalized MM equation; all 178 data points were accommodated on a single graph. Response rates from {approx}1% to >95% were well fit. The findings contradict the threshold assumption and low-dose safety. Calculating risk and assuming additivity of effects from multiple chemicals acting through the same mechanism rather than assuming a safe dose for nonthresholded curves is appropriate.

  9. Hypothesis: Bones Toughness Arises from the Suppression of Elastic Waves

    PubMed Central

    Davies, Benjamin; King, Alice; Newman, Peter; Minett, Andrew; Dunstan, Colin R.; Zreiqat, Hala

    2014-01-01

    Bone and other natural material exhibit a combination of strength and toughness that far exceeds that of synthetic structural materials. Bone's toughness is a result of numerous extrinsic and intrinsic toughening mechanisms that operate synergistically at multiple length scales to produce a tough material. At the system level however no theory or organizational principle exists to explain how so many individual toughening mechanisms can work together. In this paper, we utilize the concept of phonon localization to explain, at the system level, the role of hierarchy, material heterogeneity, and the nanoscale dimensions of biological materials in producing tough composites. We show that phonon localization and attenuation, using a simple energy balance, dynamically arrests crack growth, prevents the cooperative growth of cracks, and allows for multiple toughening mechanisms to work simultaneously in heterogeneous materials. In turn, the heterogeneous, hierarchal, and multiscale structure of bone (which is generic to biological materials such as bone and nacre) can be rationalized because of the unique ability of such a structure to localize phonons of all wavelengths. PMID:25518898

  10. Hypothesis: bones toughness arises from the suppression of elastic waves.

    PubMed

    Davies, Benjamin; King, Alice; Newman, Peter; Minett, Andrew; Dunstan, Colin R; Zreiqat, Hala

    2014-01-01

    Bone and other natural material exhibit a combination of strength and toughness that far exceeds that of synthetic structural materials. Bone's toughness is a result of numerous extrinsic and intrinsic toughening mechanisms that operate synergistically at multiple length scales to produce a tough material. At the system level however no theory or organizational principle exists to explain how so many individual toughening mechanisms can work together. In this paper, we utilize the concept of phonon localization to explain, at the system level, the role of hierarchy, material heterogeneity, and the nanoscale dimensions of biological materials in producing tough composites. We show that phonon localization and attenuation, using a simple energy balance, dynamically arrests crack growth, prevents the cooperative growth of cracks, and allows for multiple toughening mechanisms to work simultaneously in heterogeneous materials. In turn, the heterogeneous, hierarchal, and multiscale structure of bone (which is generic to biological materials such as bone and nacre) can be rationalized because of the unique ability of such a structure to localize phonons of all wavelengths. PMID:25518898

  11. Hypothesis: Bones Toughness Arises from the Suppression of Elastic Waves

    NASA Astrophysics Data System (ADS)

    Davies, Benjamin; King, Alice; Newman, Peter; Minett, Andrew; Dunstan, Colin R.; Zreiqat, Hala

    2014-12-01

    Bone and other natural material exhibit a combination of strength and toughness that far exceeds that of synthetic structural materials. Bone's toughness is a result of numerous extrinsic and intrinsic toughening mechanisms that operate synergistically at multiple length scales to produce a tough material. At the system level however no theory or organizational principle exists to explain how so many individual toughening mechanisms can work together. In this paper, we utilize the concept of phonon localization to explain, at the system level, the role of hierarchy, material heterogeneity, and the nanoscale dimensions of biological materials in producing tough composites. We show that phonon localization and attenuation, using a simple energy balance, dynamically arrests crack growth, prevents the cooperative growth of cracks, and allows for multiple toughening mechanisms to work simultaneously in heterogeneous materials. In turn, the heterogeneous, hierarchal, and multiscale structure of bone (which is generic to biological materials such as bone and nacre) can be rationalized because of the unique ability of such a structure to localize phonons of all wavelengths.

  12. Cluster-span threshold: An unbiased threshold for binarising weighted complete networks in functional connectivity analysis.

    PubMed

    Smith, Keith; Azami, Hamed; Parra, Mario A; Starr, John M; Escudero, Javier

    2015-08-01

    We propose a new unbiased threshold for network analysis named the Cluster-Span Threshold (CST). This is based on the clustering coefficient, C, following logic that a balance of `clustering' to `spanning' triples results in a useful topology for network analysis and that the product of complementing properties has a unique value only when perfectly balanced. We threshold networks by fixing C at this balanced value, rather than fixing connection density at an arbitrary value, as has been the trend. We compare results from an electroencephalogram data set of volunteers performing visual short term memory tasks of the CST alongside other thresholds, including maximum spanning trees. We find that the CST holds as a sensitive threshold for distinguishing differences in the functional connectivity between tasks. This provides a sensitive and objective method for setting a threshold on weighted complete networks which may prove influential on the future of functional connectivity research. PMID:26736883

  13. Intraosseous verrucous carcinoma arising from an orthokeratinized odontogenic keratocyst: A report of a rarest entity

    PubMed Central

    Kamarthi, Nagaraju; Palakshappa, Suhasini Gotur; Wadhwan, Vijay; Mohan, Raviprakash Sasankoti

    2016-01-01

    Intraosseous verrucous carcinomas (VCs) arising from odontogenic cysts are a rare entity. An unusual case of a VC arising from the orthokeratinized odontogenic cyst is described for the first time. The microscopic features of the lesion are presented.

  14. Experimental characterization of multiscale and multifield turbulence as a critical gradient threshold is surpassed in the DIII-D tokamaka)

    NASA Astrophysics Data System (ADS)

    Hillesheim, J. C.; DeBoo, J. C.; Peebles, W. A.; Carter, T. A.; Wang, G.; Rhodes, T. L.; Schmitz, L.; McKee, G. R.; Yan, Z.; Staebler, G. M.; Burrell, K. H.; Doyle, E. J.; Holland, C.; Petty, C. C.; Smith, S. P.; White, A. E.; Zeng, L.

    2013-05-01

    A critical gradient for long wavelength (kθρs≲0.4) electron temperature fluctuations has been observed in an experiment in the DIII-D tokamak [J. L. Luxon, Nucl. Fusion 42, 614 (2002)], where below a threshold value of LTe-1=|∇Te|/Te electron temperature fluctuations are constant and above they steadily increase. Above the critical gradient, the electron heat flux inferred by power balance also increases rapidly. Critical gradients are a predicted attribute of turbulence arising from linear instabilities and are thought to be related to transport stiffness. The presented results are the first direct, systematic demonstration of critical gradient behavior in turbulence measurements in a tokamak. The experiment was performed by changing the deposition location of electron cyclotron heating shot-to-shot to locally scan LTe-1 at r/a = 0.6 in L-mode plasmas; rotation was also varied by changing the momentum input from neutral beam injection. Temperature fluctuations were measured with a correlation electron cyclotron emission (CECE) radiometry system. In addition to the CECE measurements, an array of turbulence measurements were acquired to characterize fluctuations in multiple fields and at multiple scales as LTe-1 and rotation were modified: long wavelength (kθρs≲0.5) density fluctuations were acquired with beam emission spectroscopy, the phase angle between electron temperature and density fluctuations was measured by coupling the CECE system and a reflectometer, intermediate scale (kθρs˜0.8) density fluctuations were measured with a Doppler backscattering (DBS) system, and low frequency flows were also measured with DBS. The accumulated measurements and trends constrain identification of the instability responsible for the observed critical gradient to the ∇Te-driven trapped electron mode.

  15. MRI of germinomas arising from the basal ganglia and thalamus.

    PubMed

    Kim, D I; Yoon, P H; Ryu, Y H; Jeon, P; Hwang, G J

    1998-08-01

    We reviewed the MRI findings of germinomas originating from the basal ganglia, thalamus or deep white matter in 13 patients with 14 germinomas, excluding those in the suprasellar or pineal regions. Ten cases were confirmed as germinomas by stereotaxic biopsy, three by partial and one by total removal of the tumour. Analysis was focussed on the location and the signal characteristic of the tumour, haemorrhage, cysts within the tumour and any other associated findings. Thirteen of the tumours were in the basal ganglia and one in the thalamus. Haemorrhage was observed in seven patients, while twelve showed multiple cysts. Associated ipsilateral cerebral hemiatrophy was seen in three patients. The signal intensity of the parenchymal germinomas was heterogeneous on T1- and T2-weighted images due to haemorrhage, cysts and solid portions. We also report the MRI findings of germinomas in an early stage in two patients. PMID:9763338

  16. Electron-nuclear energy sharing in above-threshold multiphoton dissociative ionization of H2.

    PubMed

    Wu, J; Kunitski, M; Pitzer, M; Trinter, F; Schmidt, L Ph H; Jahnke, T; Magrakvelidze, M; Madsen, C B; Madsen, L B; Thumm, U; Dörner, R

    2013-07-12

    We report experimental observation of the energy sharing between electron and nuclei in above-threshold multiphoton dissociative ionization of H2 by strong laser fields. The absorbed photon energy is shared between the ejected electron and nuclei in a correlated fashion, resulting in multiple diagonal lines in their joint energy spectrum governed by the energy conservation of all fragment particles. PMID:23889391

  17. A STATISTICAL MODELING METHODOLOGY FOR THE DETECTION, QUANTIFICATION, AND PREDICTION OF ECOLOGICAL THRESHOLDS

    EPA Science Inventory

    This study will provide a general methodology for integrating threshold information from multiple species ecological metrics, allow for prediction of changes of alternative stable states, and provide a risk assessment tool that can be applied to adaptive management. The integr...

  18. The stability of color discrimination threshold determined using pseudoisochromatic test plates

    NASA Astrophysics Data System (ADS)

    Zutere, B.; Jurasevska Luse, K.; Livzane, A.

    2014-09-01

    Congenital red-green color vision deficiency is one of the most common genetic disorders. A previously printed set of pseudoisochromatic plates (KAMS test, 2012) was created for individual discrimination threshold determination in case of mild congenital red-green color vision deficiency using neutral colors (colors confused with gray). The diagnostics of color blind subjects was performed with Richmond HRR (4th edition, 2002) test, Oculus HMC anomaloscope, and further the examination was made using the KAMS test. 4 male subjects aged 20 to 24 years old participated in the study: all of them were diagnosed with deuteranomalia. Due to the design of the plates, the threshold of every subject in each trial was defined as the plate total color difference value ΔE at which the stimulus was detected 75% of the time, so the just-noticeable difference (jnd) was calculated in CIE LAB DeltaE (ΔE) units. Authors performed repeated discrimination threshold measurements (5 times) for all four subjects under controlled illumination conditions. Psychophysical data were taken by sampling an observer's performance on a psychophysical task at a number of different stimulus saturation levels. Results show that a total color difference value ΔE threshold exists for each individual tested with the KAMS pseudoisochromatic plates, this threshold value does not change significantly in multiple measurements. Deuteranomal threshold values aquired using greenish plates of KAMS test are significantly higher than thresholds acquired using reddish plates. A strong positive correlation (R=0.94) exists between anomaloscope matching range (MR) and deuteranomal thresholds aquired by the KAMS test and (R=0.81) between error score in the Richmond HRR test and thresholds aquired by the KAMS test.

  19. Multiple Sclerosis

    MedlinePlus

    Multiple sclerosis (MS) is a nervous system disease that affects your brain and spinal cord. It damages the ... attacks healthy cells in your body by mistake. Multiple sclerosis affects women more than men. It often begins ...

  20. Multiple Pregnancy

    MedlinePlus

    ... is called multiple pregnancy . If more than one egg is released during the menstrual cycle and each ... fraternal twins (or more). When a single fertilized egg splits, it results in multiple identical embryos. This ...

  1. Multiple myeloma

    MedlinePlus

    Plasma cell dyscrasia; Plasma cell myeloma; Malignant plasmacytoma; Plasmacytoma of bone; Myeloma - multiple ... Multiple myeloma most commonly causes: Low red blood cell count ( anemia ), which can lead to fatigue and ...

  2. Ignition threshold for impact-generated fires

    NASA Astrophysics Data System (ADS)

    Durda, Daniel D.; Kring, David A.

    2004-08-01

    Widespread fires can be generated after large impact events by atmospheric heating caused by the reaccretion of high-energy, vapor-rich plume material. We examine the threshold irradiance levels necessary for spontaneous and pilot ignition of various types of vegetation and define three specific cases for investigation: (1) 51 kW/m2 for a period of at least 2 min to spontaneously ignite wood; (2) 20 kW/m2 for a period of at least 20 min to ignite wood in the presence of an ignition source; and (3) 28 kW/m2 for a period of at least 1 min to ignite foliage, rotten wood, and forest litter. The threshold ejected plume mass for continent-wide spontaneous ignition of wood is ~2 to 6 × 1015 kg, independent of impact location but dependent on the details of the ejecta speed distribution. The threshold ejected plume mass for global spontaneous ignition of wood is in the range ~1 to 2 × 1016 kg. The threshold plume masses for continent-wide and global fires are very nearly the same for piloted ignition of wood, while the threshold plume masses for continent-wide and global ignition of leaves and forest litter are significantly lower, by a factor of ~2 to 3. Impact craters of at least 85 km diameter are needed to produce continental-scale fires, and craters of ~135 km diameter are needed for global-scale fires.

  3. Thresholds for Epidemic Spreading in Networks

    NASA Astrophysics Data System (ADS)

    Castellano, Claudio; Pastor-Satorras, Romualdo

    2010-11-01

    We study the threshold of epidemic models in quenched networks with degree distribution given by a power-law. For the susceptible-infected-susceptible model the activity threshold λc vanishes in the large size limit on any network whose maximum degree kmax⁡ diverges with the system size, at odds with heterogeneous mean-field (HMF) theory. The vanishing of the threshold has nothing to do with the scale-free nature of the network but stems instead from the largest hub in the system being active for any spreading rate λ>1/kmax⁡ and playing the role of a self-sustained source that spreads the infection to the rest of the system. The susceptible-infected-removed model displays instead agreement with HMF theory and a finite threshold for scale-rich networks. We conjecture that on quenched scale-rich networks the threshold of generic epidemic models is vanishing or finite depending on the presence or absence of a steady state.

  4. Threshold of the precedence effect in noise

    PubMed Central

    Freyman, Richard L.; Griffin, Amanda M.; Zurek, Patrick M.

    2014-01-01

    Three effects that show a temporal asymmetry in the influence of interaural cues were studied through the addition of masking noise: (1) The transient precedence effect—the perceptual dominance of a leading transient over a similar lagging transient; (2) the ongoing precedence effect—lead dominance with lead and lag components that extend in time; and (3) the onset capture effect—determination by an onset transient of the lateral position of an otherwise ambiguous extended trailing sound. These three effects were evoked with noise-burst stimuli and were compared in the presence of masking noise. Using a diotic noise masker, detection thresholds for stimuli with lead/lag interaural delays of 0/500 μs were compared to those with 500/0 μs delays. None of the three effects showed a masking difference between those conditions, suggesting that none of the effects is operative at masked threshold. A task requiring the discrimination between stimuli with 500/0 and 0/500 μs interaural delays was used to determine the threshold for each effect in noise. The results showed similar thresholds in noise (10–13 dB SL) for the transient and ongoing precedence effects, but a much higher threshold (33 dB SL) for onset capture of an ambiguous trailing sound. PMID:24815272

  5. Finger Multiplication

    ERIC Educational Resources Information Center

    Simanihuruk, Mudin

    2011-01-01

    Multiplication facts are difficult to teach. Therefore many researchers have put a great deal of effort into finding multiplication strategies. Sherin and Fuson (2005) provided a good survey paper on the multiplication strategies research area. Kolpas (2002), Rendtorff (1908), Dabell (2001), Musser (1966) and Markarian (2009) proposed the finger…

  6. Multiple Sclerosis

    MedlinePlus

    ... Awards Enhancing Diversity Find People About NINDS NINDS Multiple Sclerosis Information Page Condensed from Multiple Sclerosis: Hope Through ... en Español Additional resources from MedlinePlus What is Multiple Sclerosis? An unpredictable disease of the central nervous system, ...

  7. L-H Threshold Studies in NSTX

    SciTech Connect

    Kaye, S. M.; Maingi, Rajesh; Battaglia, D. J.; Bell, R. E.; Chang, C. S.; Hosea, J.; Kugel, H. W.; LaBlanc, B. P.; Meyer, H.; Wilson, J. R.

    2011-01-01

    Recent experiments in the low aspect ratio National Spherical Torus Experiment (NSTX) have been run in support of the high priority ITER and ITPA issue of access to the H-mode. Specifically, a series of experiments showed reduced power threshold values for deuterium versus helium plasmas, and for plasmas with lower current, lower triangularity and with lithium conditioning. Application of n = 3 fields at the plasma edge resulted in higher power thresholds. To within the constraints of temporal and spatial resolutions, no systematic difference in T(e), n(e), p(e), T(i), v or their derivatives was found in discharges that transitioned into the H-mode versus those at slightly lower power that did not. Finally, H(98y,2) similar to 1 confinement quality could be achieved for powers just above the threshold power in ELM-free conditions.

  8. L-H Threshold Studies in NSTX

    SciTech Connect

    Kaye, S M; Battaglia, D; Bell, R E; Chang, C S; Hosea, J; Kugel, H; LeBlanc, B P; Meyer, H; Park, G Y

    2011-09-06

    Recent experiments in the low aspect ratio National Spherical Torus Experiment (NSTX) have been run in support of the high priority ITER and ITPA issue of access to the H-mode. Specifically, a series of experiments showed reduced power threshold values for deuterium vs helium plasmas, and for plasmas with lower current, lower triangularity and with lithium conditioning. Application of n=3 fields at the plasma edge resulted in higher power thresholds. To within the constraints of temporal and spatial resolutions, no systematic difference in T{sub e}, n{sub e}, p{sub e}, T{sub i}, v or their derivatives was found in discharges that transitioned into the H-mode versus those at slightly lower power that did not. Finally, H{sub 98y,2} {approx} 1 confinement quality could be achieved for powers just above the threshold power in ELM-free conditions.

  9. Effects of pulse duration on magnetostimulation thresholds

    SciTech Connect

    Saritas, Emine U.; Goodwill, Patrick W.; Conolly, Steven M.

    2015-06-15

    Purpose: Medical imaging techniques such as magnetic resonance imaging and magnetic particle imaging (MPI) utilize time-varying magnetic fields that are subject to magnetostimulation limits, which often limit the speed of the imaging process. Various human-subject experiments have studied the amplitude and frequency dependence of these thresholds for gradient or homogeneous magnetic fields. Another contributing factor was shown to be number of cycles in a magnetic pulse, where the thresholds decreased with longer pulses. The latter result was demonstrated on two subjects only, at a single frequency of 1.27 kHz. Hence, whether the observed effect was due to the number of cycles or due to the pulse duration was not specified. In addition, a gradient-type field was utilized; hence, whether the same phenomenon applies to homogeneous magnetic fields remained unknown. Here, the authors investigate the pulse duration dependence of magnetostimulation limits for a 20-fold range of frequencies using homogeneous magnetic fields, such as the ones used for the drive field in MPI. Methods: Magnetostimulation thresholds were measured in the arms of six healthy subjects (age: 27 ± 5 yr). Each experiment comprised testing the thresholds at eight different pulse durations between 2 and 125 ms at a single frequency, which took approximately 30–40 min/subject. A total of 34 experiments were performed at three different frequencies: 1.2, 5.7, and 25.5 kHz. A solenoid coil providing homogeneous magnetic field was used to induce stimulation, and the field amplitude was measured in real time. A pre-emphasis based pulse shaping method was employed to accurately control the pulse durations. Subjects reported stimulation via a mouse click whenever they felt a twitching/tingling sensation. A sigmoid function was fitted to the subject responses to find the threshold at a specific frequency and duration, and the whole procedure was repeated at all relevant frequencies and pulse durations

  10. Investigation of signal thresholding to reduce the effects of instrument noise of an EMCCD based micro-CT system

    NASA Astrophysics Data System (ADS)

    Podgorsak, Alexander R.; Bysani Krishnakumar, Sumukh; Setlur Nagesh, S. V.; Bednarek, Daniel R.; Rudin, Stephen; Ionita, Ciprian N.

    2016-03-01

    This project investigated the signal thresholding effectiveness at reducing the instrument noise of an electron multiplying charged coupled device (EMCCD) based micro-CT system at low x-ray exposure levels. Scans of a mouse spine and an iodine phantom were taken using an EMCCD detector coupled with a micro-CT system. An iodine filter of 4 mg/cm2 area density was placed in the beam. The output signal was thresholded using some multiple of the inherent background noise. For each threshold, 100, 200, and 300 frames were summed for each projection to evaluate the effect on the reconstructed image. The projection images from the scans were compared using line profiles and their SNR. Our results indicate that, as the threshold was increased, the line profiles of the projection images showed less statistical variation, but also lower signal levels, so that the SNR of the projection images decreased as the threshold increased. When the line profile of a projection image obtained using a signal threshold is compared with one obtained using energy integrating mode, the profile obtained using thresholding had less variation than that obtained using energy integration, which indicates less instrument noise. The SNR at the edges of the scan object is higher in the thresholded images when compared with the energy integrated projection images. We conclude that thresholding the output signal from an EMCCD detector at low x-ray exposure levels is an effective method to reduce the instrument noise of an EMCCD detector.

  11. Multiplicity Counting

    SciTech Connect

    Geist, William H.

    2015-12-01

    This set of slides begins by giving background and a review of neutron counting; three attributes of a verification item are discussed: 240Pueff mass; α, the ratio of (α,n) neutrons to spontaneous fission neutrons; and leakage multiplication. It then takes up neutron detector systems – theory & concepts (coincidence counting, moderation, die-away time); detector systems – some important details (deadtime, corrections); introduction to multiplicity counting; multiplicity electronics and example distributions; singles, doubles, and triples from measured multiplicity distributions; and the point model: multiplicity mathematics.

  12. Predictability of threshold exceedances in dynamical systems

    NASA Astrophysics Data System (ADS)

    Bódai, Tamás

    2015-12-01

    In a low-order model of the general circulation of the atmosphere we examine the predictability of threshold exceedance events of certain observables. The likelihood of such binary events-the cornerstone also for the categoric (as opposed to probabilistic) prediction of threshold exceedances-is established from long time series of one or more observables of the same system. The prediction skill is measured by a summary index of the ROC curve that relates the hit- and false alarm rates. Our results for the examined systems suggest that exceedances of higher thresholds are more predictable; or in other words: rare large magnitude, i.e., extreme, events are more predictable than frequent typical events. We find this to hold provided that the bin size for binning time series data is optimized, but not necessarily otherwise. This can be viewed as a confirmation of a counterintuitive (and seemingly contrafactual) statement that was previously formulated for more simple autoregressive stochastic processes. However, we argue that for dynamical systems in general it may be typical only, but not universally true. We argue that when there is a sufficient amount of data depending on the precision of observation, the skill of a class of data-driven categoric predictions of threshold exceedances approximates the skill of the analogous model-driven prediction, assuming strictly no model errors. Therefore, stronger extremes in terms of higher threshold levels are more predictable both in case of data- and model-driven prediction. Furthermore, we show that a quantity commonly regarded as a measure of predictability, the finite-time maximal Lyapunov exponent, does not correspond directly to the ROC-based measure of prediction skill when they are viewed as functions of the prediction lead time and the threshold level. This points to the fact that even if the Lyapunov exponent as an intrinsic property of the system, measuring the instability of trajectories, determines predictability

  13. Energy Switching Threshold for Climatic Benefits

    NASA Astrophysics Data System (ADS)

    Zhang, X.; Cao, L.; Caldeira, K.

    2013-12-01

    Climate change is one of the great challenges facing humanity currently and in the future. Its most severe impacts may still be avoided if efforts are made to transform current energy systems (1). A transition from the global system of high Greenhouse Gas (GHG) emission electricity generation to low GHG emission energy technologies is required to mitigate climate change (2). Natural gas is increasingly seen as a choice for transitions to renewable sources. However, recent researches in energy and climate puzzled about the climate implications of relying more energy on natural gas. On one hand, a shift to natural gas is promoted as climate mitigation because it has lower carbon per unit energy than coal (3). On the other hand, the effect of switching to natural gas on nuclear-power and other renewable energies development may offset benefits from fuel-switching (4). Cheap natural gas is causing both coal plants and nuclear plants to close in the US. The objective of this study is to measure and evaluate the threshold of energy switching for climatic benefits. We hypothesized that the threshold ratio of energy switching for climatic benefits is related to GHGs emission factors of energy technologies, but the relation is not linear. A model was developed to study the fuel switching threshold for greenhouse gas emission reduction, and transition from coal and nuclear electricity generation to natural gas electricity generation was analyzed as a case study. The results showed that: (i) the threshold ratio of multi-energy switching for climatic benefits changes with GHGs emission factors of energy technologies. (ii)The mathematical relation between the threshold ratio of energy switching and GHGs emission factors of energies is a curved surface function. (iii) The analysis of energy switching threshold for climatic benefits can be used for energy and climate policy decision support.

  14. Methods for threshold determination in multiplexed assays

    DOEpatents

    Tammero, Lance F. Bentley; Dzenitis, John M; Hindson, Benjamin J

    2014-06-24

    Methods for determination of threshold values of signatures comprised in an assay are described. Each signature enables detection of a target. The methods determine a probability density function of negative samples and a corresponding false positive rate curve. A false positive criterion is established and a threshold for that signature is determined as a point at which the false positive rate curve intersects the false positive criterion. A method for quantitative analysis and interpretation of assay results together with a method for determination of a desired limit of detection of a signature in an assay are also described.

  15. Linear pattern dynamics in nonlinear threshold systems

    SciTech Connect

    Rundle, John B.; Klein, W.; Tiampo, Kristy; Gross, Susanna

    2000-03-01

    Complex nonlinear threshold systems frequently show space-time behavior that is difficult to interpret. We describe a technique based upon a Karhunen-Loeve expansion that allows dynamical patterns to be understood as eigenstates of suitably constructed correlation operators. The evolution of space-time patterns can then be viewed in terms of a ''pattern dynamics'' that can be obtained directly from observable data. As an example, we apply our methods to a particular threshold system to forecast the evolution of patterns of observed activity. Finally, we perform statistical tests to measure the quality of the forecasts. (c) 2000 The American Physical Society.

  16. Sexual conflict arising from extrapair matings in birds.

    PubMed

    Chaine, Alexis S; Montgomerie, Robert; Lyon, Bruce E

    2015-03-01

    The discovery that extrapair copulation (EPC) and extrapair paternity (EPP) are common in birds led to a paradigm shift in our understanding of the evolution of mating systems. The prevalence of extrapair matings in pair-bonded species sets the stage for sexual conflict, and a recent focus has been to consider how this conflict can shape variation in extrapair mating rates. Here, we invert the causal arrow and consider the consequences of extrapair matings for sexual conflict. Extrapair matings shift sexual conflict from a simple two-player (male vs. female) game to a game with three or more players, the nature of which we illustrate with simple diagrams that highlight the net costs and benefits of extrapair matings to each player. This approach helps identify the sorts of traits that might be under selection because of sexual conflict. Whether EPP is driven primarily by the extrapair male or the within-pair female profoundly influences which players are in conflict, but the overall pattern of conflict varies little among different mating systems. Different aspects of conflict are manifest at different stages of the breeding cycle and can be profitably considered as distinct episodes of selection caused by conflict. This perspective is illuminating both because conflict between specific players can change across episodes and because the traits that evolve to mediate conflict likely differ between episodes. Although EPP clearly leads to sexual conflict, we suggest that the link between sexual conflict and multiple paternity might be usefully understood by examining how deviations from lifetime sexual monogamy influence sexual conflict. PMID:25605708

  17. Covalent thiol adducts arising from reactive intermediates of cocaine biotransformation.

    PubMed

    Schneider, Kevin J; DeCaprio, Anthony P

    2013-11-18

    Exposure to cocaine results in the depletion of hepatocellular glutathione and macromolecular protein binding in humans. Such cocaine-induced responses have generally been attributed to oxidative stress and reactive metabolites resulting from oxidative activation of the cocaine tropane nitrogen. However, little conclusive data exists on the mechanistic pathways leading to protein modification or the structure and specificity of cocaine-derived adduction products. We now report a previously uncharacterized route of cocaine bioactivation leading to the covalent adduction of biological thiols, including cysteine and glutathione. Incubation of cocaine with biological nucleophiles in an in vitro biotransformation system containing human liver microsomes identified a monooxygenase-mediated event leading to the oxidation of, and subsequent sulfhydryl addition to, the cocaine aryl moiety. Adduct structures were confirmed using ultra-high performance liquid chromatography coupled to high resolution, high mass accuracy mass spectrometry. Examination of assays containing transgenic bactosomes expressing single human cytochrome P450 isoforms determined the role of P450s 1A2, 2C19, and 2D6 in the oxidation process resulting in adduct formation. P450-catalyzed aryl epoxide formation and subsequent attack by free nucleophilic moieties is consistent with the resulting adduct structures, mechanisms of formation, and the empirical observation of multiple structural and stereo isomers. Analogous adduction mechanisms were maintained across all sulfhydryl-containing nucleophile models examined; N-acetylcysteine, glutathione, and a synthetic cysteine-containing hexapeptide. Predictive in silico calculations of molecular reactivity and electrophilicity/nucleophilicity were compared to the results of in vitro assay incubations in order to better understand the adduction process using the principles of hard and soft acid and base (HSAB) theory. This study elucidated a novel metabolic

  18. Determination of optimum threshold values for EMG time domain features; a multi-dataset investigation

    NASA Astrophysics Data System (ADS)

    Nlandu Kamavuako, Ernest; Scheme, Erik Justin; Englehart, Kevin Brian

    2016-08-01

    Objective. For over two decades, Hudgins’ set of time domain features have extensively been applied for classification of hand motions. The calculation of slope sign change and zero crossing features uses a threshold to attenuate the effect of background noise. However, there is no consensus on the optimum threshold value. In this study, we investigate for the first time the effect of threshold selection on the feature space and classification accuracy using multiple datasets. Approach. In the first part, four datasets were used, and classification error (CE), separability index, scatter matrix separability criterion, and cardinality of the features were used as performance measures. In the second part, data from eight classes were collected during two separate days with two days in between from eight able-bodied subjects. The threshold for each feature was computed as a factor (R = 0:0.01:4) times the average root mean square of data during rest. For each day, we quantified CE for R = 0 (CEr0) and minimum error (CEbest). Moreover, a cross day threshold validation was applied where, for example, CE of day two (CEodt) is computed based on optimum threshold from day one and vice versa. Finally, we quantified the effect of the threshold when using training data from one day and test data of the other. Main results. All performance metrics generally degraded with increasing threshold values. On average, CEbest (5.26 ± 2.42%) was significantly better than CEr0 (7.51 ± 2.41%, P = 0.018), and CEodt (7.50 ± 2.50%, P = 0.021). During the two-fold validation between days, CEbest performed similar to CEr0. Interestingly, when using the threshold values optimized per subject from day one and day two respectively, on the cross-days classification, the performance decreased. Significance. We have demonstrated that threshold value has a strong impact on the feature space and that an optimum threshold can be quantified. However, this optimum threshold is highly data and

  19. On the two steps threshold selection for over-threshold modelling of extreme events

    NASA Astrophysics Data System (ADS)

    Bernardara, Pietro; Mazas, Franck; Weiss, Jerome; Andreewsky, Marc; Kergadallan, Xavier; Benoit, Michel; Hamm, Luc

    2013-04-01

    The estimation of the probability of occurrence of extreme events is traditionally achieved by fitting a probability distribution on a sample of extreme observations. In particular, the extreme value theory (EVT) states that values exceeding a given threshold converge through a Generalized Pareto Distribution (GPD) if the original sample is composed of independent and identically distributed values. However, the temporal series of sea and ocean variables usually show strong temporal autocorrelation. Traditionally, in order to select independent events for the following statistical analysis, the concept of a physical threshold is introduced: events that excess that threshold are defined as "extreme events". This is the so-called "Peak Over a Threshold (POT)" sampling, widely spread in the literature and currently used for engineering applications among many others. In the past, the threshold for the statistical sampling of extreme values asymptotically convergent toward GPD and the threshold for the physical selection of independent extreme events were confused, as the same threshold was used for both sampling data and to meet the hypothesis of extreme value convergence, leading to some incoherencies. In particular, if the two steps are performed simultaneously, the number of peaks over the threshold can increase but also decrease when the threshold decreases. This is logic in a physical point of view, since the definition of the sample of "extreme events" changes, but is not coherent with the statistical theory. We introduce a two-steps threshold selection for over-threshold modelling, aiming to discriminate (i) a physical threshold for the selection of extreme and independent events, and (ii) a statistical threshold for the optimization of the coherence with the hypothesis of the EVT. The former is a physical events identification procedure (also called "declustering") aiming at selecting independent extreme events. The latter is a purely statistical optimization

  20. Asymmetries arising from the space-filling nature of vascular networks

    NASA Astrophysics Data System (ADS)

    Hunt, David; Savage, Van M.

    2016-06-01

    Cardiovascular networks span the body by branching across many generations of vessels. The resulting structure delivers blood over long distances to supply all cells with oxygen via the relatively short-range process of diffusion at the capillary level. The structural features of the network that accomplish this density and ubiquity of capillaries are often called space-filling. There are multiple strategies to fill a space, but some strategies do not lead to biologically adaptive structures by requiring too much construction material or space, delivering resources too slowly, or using too much power to move blood through the system. We empirically measure the structure of real networks (18 humans and 1 mouse) and compare these observations with predictions of model networks that are space-filling and constrained by a few guiding biological principles. We devise a numerical method that enables the investigation of space-filling strategies and determination of which biological principles influence network structure. Optimization for only a single principle creates unrealistic networks that represent an extreme limit of the possible structures that could be observed in nature. We first study these extreme limits for two competing principles, minimal total material and minimal path lengths. We combine these two principles and enforce various thresholds for balance in the network hierarchy, which provides a novel approach that highlights the tradeoffs faced by biological networks and yields predictions that better match our empirical data.

  1. Asymmetries arising from the space-filling nature of vascular networks.

    PubMed

    Hunt, David; Savage, Van M

    2016-06-01

    Cardiovascular networks span the body by branching across many generations of vessels. The resulting structure delivers blood over long distances to supply all cells with oxygen via the relatively short-range process of diffusion at the capillary level. The structural features of the network that accomplish this density and ubiquity of capillaries are often called space-filling. There are multiple strategies to fill a space, but some strategies do not lead to biologically adaptive structures by requiring too much construction material or space, delivering resources too slowly, or using too much power to move blood through the system. We empirically measure the structure of real networks (18 humans and 1 mouse) and compare these observations with predictions of model networks that are space-filling and constrained by a few guiding biological principles. We devise a numerical method that enables the investigation of space-filling strategies and determination of which biological principles influence network structure. Optimization for only a single principle creates unrealistic networks that represent an extreme limit of the possible structures that could be observed in nature. We first study these extreme limits for two competing principles, minimal total material and minimal path lengths. We combine these two principles and enforce various thresholds for balance in the network hierarchy, which provides a novel approach that highlights the tradeoffs faced by biological networks and yields predictions that better match our empirical data. PMID:27415278

  2. Temperature thresholds to freeze damage in cranberry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sprinkler irrigation is required for frost protection of cranberry and is arguably the most important cultural practice used in production of the crop. A study was initiated in a commercial bed of ‘Stevens’ cranberry located in Langlois, OR. The objectives are to identify temperature thresholds to...

  3. Mandated Reporting Thresholds for Community Professionals

    ERIC Educational Resources Information Center

    Crowell, Kathryn; Levi, Benjamin H.

    2012-01-01

    This study examines how community-based mandated reporters understand and interpret "reasonable suspicion", the standard threshold for mandated reporting of suspected child abuse. Respondents were asked to identify the probability necessary for "suspicion of child abuse" to constitute "reasonable suspicion". Data were analyzed for internal…

  4. 40 CFR 98.151 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ....151 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING HCFC-22 Production and HFC-23 Destruction § 98.151 Reporting threshold... HFC-23 destruction process and the facility meets the requirements of either § 98.2(a)(1) or (a)(2)....

  5. 40 CFR 98.431 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.431 Section 98.431 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Importers and Exporters of Fluorinated Greenhouse Gases Contained in...

  6. Speech reception thresholds in various interference conditions

    NASA Astrophysics Data System (ADS)

    Carr, Suzanne P.; Colburn, H. Steven

    2001-05-01

    Speech intelligibility is integral to human verbal communication; however, our understanding of the effects of competing noise, room reverberation, and frequency range restriction is incomplete. Using virtual stimuli, the dependence of intelligibility threshold levels on the extent of room reverberation, the relative locations of speech target and masking noise, and the available frequency content of the speech and the masking noise is explored. Speech-shaped masking noise and target sentences have three spectral conditions: wideband, high pass above 2-kHz, and low pass below 2-kHz. The 2-kHz cutoff was chosen to approximately bisect the range of frequencies most important in speech, and the high pass noise condition simulates high-frequency hearing loss. Reverberation conditions include a pseudo-anechoic case, a moderately reverberant ``classroom'' case, and a very reverberant ``bathroom'' case. Both binaural and monaural intelligibility are measured. Preliminary results show that source separation decreases thresholds, reverberation increases thresholds, and low frequency noise reverberates more in the rooms, contributing to increasing thresholds along with the effects of the upward spread of masking. The energetic effects of reverberation are explored. [Work supported by NIH DC00100.

  7. Auricular electrical stimulation and dental pain threshold.

    PubMed Central

    Simmons, M. S.; Oleson, T. D.

    1993-01-01

    A modified double-blind evaluation of naloxone reversibility of dental analgesia produced by auricular electrical stimulation (AES) was examined in 40 subjects assigned randomly to one of four groups: AES followed by saline (AS), AES followed by naloxone (AN), placebo AES followed by saline (PS), and placebo AES followed by naloxone (PN). Dental pain threshold was tested using a hand-held dental pulp tester. A second investigator administered the true or placebo AES using an electrical stimulator. A third investigator injected intravenously saline or naloxone. The subjects and investigators 1 and 3 were blind to all treatment conditions. A repeated measures analysis of variance revealed a significant difference among the four groups. The AES groups exhibited a statistically significant 18% elevation of pain threshold, whereas the two placebo stimulation groups (PS and PN) remained essentially unchanged. The mean pain threshold increased to more than 23% for group AS, but fell to less than 12% for the subjects in group AN, who were given naloxone. These findings indicate a small but significant elevation of pain threshold by AES, an effect partially blocked by naloxone, suggesting an endogenous opioid system as one mechanism for AES analgesia. Images Figure 1 Figure 2 PMID:8185085

  8. Gastric Residual Volume: Rethinking the Threshold.

    PubMed

    Emami Zeydi, Amir; Sharafkhani, Mohammad; Armat, Mohammad Reza

    2016-01-01

    There are many challenges related to enteral feedings of the mechanically ventilated patient. Among the most often debated issues is the threshold for gastric residual volume before further feeding. This brief article considers the factors to be considered and reviews current thinking on the topic. PMID:27575801

  9. 40 CFR 98.121 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Fluorinated Gas Production § 98.121 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a fluorinated gas production process that... in § 98.2(a)(2), calculate process emissions from fluorinated gas production using uncontrolled...

  10. 40 CFR 98.121 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Fluorinated Gas Production § 98.121 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a fluorinated gas production process that... in § 98.2(a)(2), calculate process emissions from fluorinated gas production using uncontrolled...

  11. 40 CFR 98.121 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Fluorinated Gas Production § 98.121 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a fluorinated gas production process that... in § 98.2(a)(2), calculate process emissions from fluorinated gas production using uncontrolled...

  12. 40 CFR 98.121 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Fluorinated Gas Production § 98.121 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a fluorinated gas production process that... in § 98.2(a)(2), calculate process emissions from fluorinated gas production using uncontrolled...

  13. The gradual nature of threshold switching

    NASA Astrophysics Data System (ADS)

    Wimmer, M.; Salinga, M.

    2014-11-01

    The recent commercialization of electronic memories based on phase change materials proved the usability of this peculiar family of materials for application purposes. More advanced data storage and computing concepts, however, demand a deeper understanding especially of the electrical properties of the amorphous phase and the switching behaviour. In this work, we investigate the temporal evolution of the current through the amorphous state of the prototypical phase change material, Ge2Sb2Te5, under constant voltage. A custom-made electrical tester allows the measurement of delay times over five orders of magnitude, as well as the transient states of electrical excitation prior to the actual threshold switching. We recognize a continuous current increase over time prior to the actual threshold-switching event to be a good measure for the electrical excitation. A clear correlation between a significant rise in pre-switching-current and the later occurrence of threshold switching can be observed. This way, we found experimental evidence for the existence of an absolute minimum for the threshold voltage (or electric field respectively) holding also for time scales far beyond the measurement range.

  14. Environment as a Threshold Variable: An Examination

    ERIC Educational Resources Information Center

    Marjoribanks, Kevin

    1974-01-01

    It is often assumed that, for intellectual performance, the environment acts as a threshold variable. This assumption was investigated by examining the nature of the relationship between the learning environment of the home and verbal, number, spatial, and reasoning ability test scores. (Author/JA)

  15. Threshold Concepts in Finance: Conceptualizing the Curriculum

    ERIC Educational Resources Information Center

    Hoadley, Susan; Tickle, Leonie; Wood, Leigh N.; Kyng, Tim

    2015-01-01

    Graduates with well-developed capabilities in finance are invaluable to our society and in increasing demand. Universities face the challenge of designing finance programmes to develop these capabilities and the essential knowledge that underpins them. Our research responds to this challenge by identifying threshold concepts that are central to…

  16. Human eye color difference threshold measurement system

    NASA Astrophysics Data System (ADS)

    Liu, Lin; Zhou, Taogeng

    2013-12-01

    The human eye has the ability to distinguish millions of colors, with this feature we can identify very subtle color differences, and the measurement of human eye color difference threshold can provide a visual function diagnosis for testee. In recent years, people begin to focus on studies on visual threshold diagnostic equipment. This paper proposes a human eye color difference threshold measurement system which is based on dual integrating sphere. The system includes two pairs of dual integrating sphere and color control module. Dual integrating sphere uses to mix and produce color, and palette unit which produces primary colors (red (R), green (G), blue (B)) is embedded in dual integrating sphere. At the same time, the embedded palette unit which produces cyan (C), magenta (M), and yellow (Y) expands color area that the system can generate. One optical path based on dual integrating sphere generates standard color, the other path produces the matching color which is similar to a standard color. In the high-precision closed-loop color control module, photoelectric switch records stepper motor's origin position and limits move displacement. Precision stepper motor pushes the light-blocking panel of the palette unit to a predetermined position, while real-time monitoring the position of the light-blocking panel and mixing the ideal controllable color. Two colors that the system generates are projected onto the same target area. Subjects make a judgment on color difference threshold by observing the target eventually.

  17. Identification of Threshold Concepts for Biochemistry

    ERIC Educational Resources Information Center

    Loertscher, Jennifer; Green, David; Lewis, Jennifer E.; Lin, Sara; Minderhout, Vicky

    2014-01-01

    Threshold concepts (TCs) are concepts that, when mastered, represent a transformed understanding of a discipline without which the learner cannot progress. We have undertaken a process involving more than 75 faculty members and 50 undergraduate students to identify a working list of TCs for biochemistry. The process of identifying TCs for…

  18. Verification of the heart rate threshold.

    PubMed

    Bunc, V; Hofmann, P; Leitner, H; Gaisl, G

    1995-01-01

    Among the methods for determining anaerobic threshold (AT), the heart rate (HR) method seems to be the simplest. On the other hand, many conflicting results from comparing this method with others have been presented over the last 10 years. Therefore, the aim of this study was to compare the heart rate threshold (HRT) with the lactate turn point (LTP)-"second" break point of dependence of lactate (LA) to power output, ventilatory threshold (VT) and threshold determined by electromyography (EMGAT), all determined by the same exercise test and evaluated by the same computer algorithm. A group of 24 female students [mean age 20.5 (SD 1.6) years, maximal oxygen consumption 48.8 (SD 4.7) ml.kg-1.min-1] performed an incremental exercise test on a cycle ergometer (modified Conconi test) starting with an initial power output (PO) of 40 W with intensity increments of 10 W.min-1 until the subjects were exhausted. The HRT, LTP and EMGAT determination was done by computer-aided break-point regression analysis from dependence of functional measures on PO. The same computer algorithm was used for VT determination from the relationship between ventilation (V) and oxygen uptake (VO2) or carbon dioxide output (VCO2).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:7607203

  19. 40 CFR 98.301 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Reporting threshold. 98.301 Section 98.301 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Electrical Transmission and Distribution Equipment Use § 98.301...

  20. A Cognitive Approach to Threshold Concepts

    ERIC Educational Resources Information Center

    Walker, Guy

    2013-01-01

    This paper asks a fundamental question: what is happening inside the mind of the undergraduate during teaching and learning experiences, and how should curricula be designed to support it? A number of concepts lend themselves to providing an answer, principle among which is the relatively recent idea of Threshold Concepts. In this paper we attempt…

  1. 42 CFR 433.206 - Threshold methodology.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 42 Public Health 4 2013-10-01 2013-10-01 false Threshold methodology. 433.206 Section 433.206 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... implements appropriate tracking for purpose of claiming Federal Medicaid funding for the associated...

  2. 42 CFR 433.206 - Threshold methodology.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 42 Public Health 4 2014-10-01 2014-10-01 false Threshold methodology. 433.206 Section 433.206 Public Health CENTERS FOR MEDICARE & MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES... implements appropriate tracking for purpose of claiming Federal Medicaid funding for the associated...

  3. Speech Recognition Thresholds for Multilingual Populations.

    ERIC Educational Resources Information Center

    Ramkissoon, Ishara

    2001-01-01

    This article traces the development of speech audiometry in the United States and reports on the current status, focusing on the needs of a multilingual population in terms of measuring speech recognition threshold (SRT). It also discusses sociolinguistic considerations, alternative SRT stimuli for second language learners, and research on using…

  4. Handwriting Automaticity: The Search for Performance Thresholds

    ERIC Educational Resources Information Center

    Medwell, Jane; Wray, David

    2014-01-01

    Evidence is accumulating that handwriting has an important role in written composition. In particular, handwriting automaticity appears to relate to success in composition. This relationship has been little explored in British contexts and we currently have little idea of what threshold performance levels might be. In this paper, we report on two…

  5. Excitable neurons, firing threshold manifolds and canards.

    PubMed

    Mitry, John; McCarthy, Michelle; Kopell, Nancy; Wechselberger, Martin

    2013-01-01

    We investigate firing threshold manifolds in a mathematical model of an excitable neuron. The model analyzed investigates the phenomenon of post-inhibitory rebound spiking due to propofol anesthesia and is adapted from McCarthy et al. (SIAM J. Appl. Dyn. Syst. 11(4):1674-1697, 2012). Propofol modulates the decay time-scale of an inhibitory GABAa synaptic current. Interestingly, this system gives rise to rebound spiking within a specific range of propofol doses. Using techniques from geometric singular perturbation theory, we identify geometric structures, known as canards of folded saddle-type, which form the firing threshold manifolds. We find that the position and orientation of the canard separatrix is propofol dependent. Thus, the speeds of relevant slow synaptic processes are encoded within this geometric structure. We show that this behavior cannot be understood using a static, inhibitory current step protocol, which can provide a single threshold for rebound spiking but cannot explain the observed cessation of spiking for higher propofol doses. We then compare the analyses of dynamic and static synaptic inhibition, showing how the firing threshold manifolds of each relate, and why a current step approach is unable to fully capture the behavior of this model. PMID:23945278

  6. Erosion thresholds and land surface morphology

    NASA Astrophysics Data System (ADS)

    Dietrich, William E.; Wilson, Cathy J.; Montgomery, David R.; McKean, James; Bauer, Romy

    1992-08-01

    We propose a graphical technique to analyze the entirety of landforms in a catchment to define quantitatively the spatial variation in the dominance of different erosion processes. High-resolution digital elevation data of a 1.2 km2 hilly area where the channel network had been mapped in the field were used in the digital terrain model, TOPOG, to test threshold theories for erosion. The land surface was divided into ˜20 m2 elements whose shapes were then classified as convergent, planar, or divergent. The entire landscape plotted on a graph of area per unit contour length against surface gradient shows each planform plotting as a separate field. A simple steady-state hydrologic model was used to predict zones of saturation and areas of high pore pressure to mimic the extreme hydrologic events responsible for erosive instability of the land surface. The field observation that saturation overland flow is rare outside convergent zones provided a significant constraint on the hydrologic parameter in the model. This model was used in threshold theories to predict areas of slope instability and areas subject to erosion by saturation overland flow, both of which can contribute to channel initiation. The proportion of convergent elements predicted to exceed the threshold varies greatly with relatively small changes in surface resistance, demonstrating a high sensitivity to land use such as cattle grazing. Overall, the landscape can be divided, using erosion threshold lines, into areas prone to channel instability due to runoff and stable areas where diffusive transport predominates.

  7. 40 CFR 98.431 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-Charged Equipment or Closed-Cell Foams § 98.431 Reporting threshold. Any importer or exporter of fluorinated GHGs contained in pre-charged equipment or closed-cell foams who meets the requirements of § 98.2... or closed-cell foams....

  8. 40 CFR 98.431 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-Charged Equipment or Closed-Cell Foams § 98.431 Reporting threshold. Any importer or exporter of fluorinated GHGs contained in pre-charged equipment or closed-cell foams who meets the requirements of § 98.2... or closed-cell foams....

  9. 40 CFR 98.431 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-Charged Equipment or Closed-Cell Foams § 98.431 Reporting threshold. Any importer or exporter of fluorinated GHGs contained in pre-charged equipment or closed-cell foams who meets the requirements of § 98.2... or closed-cell foams....

  10. 49 CFR 80.13 - Threshold criteria.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Transportation Office of the Secretary of Transportation CREDIT ASSISTANCE FOR SURFACE TRANSPORTATION PROJECTS... project shall meet the following five threshold criteria: (1) The project shall be consistent with the... before the DOT and the project sponsor execute a term sheet or credit agreement that results in...

  11. 49 CFR 80.13 - Threshold criteria.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Transportation Office of the Secretary of Transportation CREDIT ASSISTANCE FOR SURFACE TRANSPORTATION PROJECTS... project shall meet the following five threshold criteria: (1) The project shall be consistent with the... before the DOT and the project sponsor execute a term sheet or credit agreement that results in...

  12. Phi Delta Kappa at the Threshold

    ERIC Educational Resources Information Center

    Walling, Donovan R.

    2006-01-01

    Since its fraternal origins a century ago, Phi Delta Kappa (PDK) International has been foremost a society of individuals joined together in professional collegiality and dedicated to tenets of leadership, service, and research in education. As PDK crosses the threshold into its second century, that early spirit of association lit in 1906, like…

  13. Robust stochastic resonance for simple threshold neurons

    NASA Astrophysics Data System (ADS)

    Kosko, Bart; Mitaim, Sanya

    2004-09-01

    Simulation and theoretical results show that memoryless threshold neurons benefit from small amounts of almost all types of additive noise and so produce the stochastic-resonance or SR effect. Input-output mutual information measures the performance of such threshold systems that use subthreshold signals. The SR result holds for all possible noise probability density functions with finite variance. The only constraint is that the noise mean must fall outside a “forbidden” threshold-related interval that the user can control—a new theorem shows that this condition is also necessary. A corollary and simulations show that the SR effect occurs for right-sided beta and Weibull noise as well. These SR results further hold for the entire uncountably infinite class of alpha-stable probability density functions. Alpha-stable noise densities have infinite variance and infinite higher-order moments and often model impulsive noise environments. The stable noise densities include the special case of symmetric bell-curve densities with thick tails such as the Cauchy probability density. The SR result for alpha-stable noise densities shows that the SR effect in threshold and thresholdlike systems is robust against occasional or even frequent violent fluctuations in noise. Regression analysis reveals both an exponential relationship for the optimal noise dispersion as a function of the alpha bell-curve tail thickness and an approximate linear relationship for the SR-maximal mutual information as a function of the alpha bell-curve tail thickness.

  14. Kaluza-Klein masses in nonprime orbifolds: Z{sub 12-I} compactification and threshold correction

    SciTech Connect

    Kim, Jihn E.; Kyae, Bumseok

    2008-05-15

    Analyzing the one-loop partition function, we discuss possible Kaluza-Klein (KK) states in the orbifold compactification of the heterotic string theory, toward the application to the threshold correction. The KK massive states associated with (relatively) large extra dimensions can arise only in nonprime orbifolds. The Gliozzi-Scherk-Olive (GSO) projection condition by a shift vector V{sup I} is somewhat relaxed above the compactification scale 1/R. We also present the other condition on Wilson line W, P{center_dot}W=integer. With the knowledge of the partition function, we obtain the threshold corrections to gauge couplings, which include the Wilson line effects. We point out the differences in string and field theoretic orbifolds.

  15. Altruism in multiplayer snowdrift games with threshold and punishment

    NASA Astrophysics Data System (ADS)

    Zhang, Chunyan; Liu, Zhongxin; Sun, Qinglin; Chen, Zengqiang

    2015-09-01

    The puzzle of cooperation attracts broader concerns of the scientific community nowadays. Here we adopt an extra mechanism of punishment in the framework of a threshold multiple-player snowdrift game employed as the scenario for the cooperation problem. Two scenarios are considered: defectors will suffer punishment regardless of the game results, and defectors will incur punishment only when the game fails. We show by analysis that given this assumption, punishing free riders can significantly influence the evolution outcomes, and the results are driven by the specific components of the punishing rule. Particularly, punishing defectors always, not only when the game fails, can be more effective for maintaining public cooperation in multi-player systems. Intriguingly larger thresholds of the game provide a more favorable scenario for the coexistence of the cooperators and defectors under a broad value range of parameters. Further, cooperators are best supported by the large punishment on defectors, and then dominate and stabilize in the population, under the premise that defectors always incur punishment regardless of whether the game ends successfully or not.

  16. Femtosecond pulse damage thresholds of dielectric coatings in vacuum

    SciTech Connect

    Michelle D. Shinn, Duy N. Nguyen, Luke A. Emmert ,Paul Schwoebel, Dinesh Patel, Carmen S. Menoni, Wolfgang Rudolph

    2011-03-01

    At 10-7 Torr, the multiple femtosecond pulse damage threshold, F(?), is about 10% of the single pulse damage fluence F(1) for hafnia and silica films compared to about 65% and 50%, respectively, at 630 Torr. In contrast, the single-pulse damage threshold is pressure independent. The decrease of F(?) with decreasing air pressure correlates with the water vapor and oxygen content of the ambient gas with the former having the greater effect. The decrease in F(?) is likely associated with an accumulation of defects derived from oxygen deficiency, for example vacancies. From atmospheric air pressure to pressures of {approx}3 x 10{sup -6} Torr, the damage 'crater' starts deterministically at the center of the beam and grows in diameter as the fluence increases. At pressure below 3x10-6 Torr, damage is initiated at random 'sites' within the exposed area in hafnia films, while the damage morphology remains deterministic in silica films. A possible explanation is that absorbing centers are created at predisposed sample sites in hafnia, for example at boundaries between crystallites, or crystalline and amorphous phases.

  17. Near-Threshold, Vibrationally-Resolved Photoionization of Molecular Nitrogen

    NASA Astrophysics Data System (ADS)

    Vangyseghem, Gaetan; Gorczyca, Thomas; Ballance, Connor

    2016-05-01

    Photoionization of molecular nitrogen N2 is investigated near the first ionization threshold using an R-matrix, multi-channel quantum defect theory (MQDT) approach. Building on an existing fixed-nuclei R-matrix photoionization model, which, in turn, is built on the UKRmol suite of codes, photoionization cross sections, as well as scattering and dipole matrices, are computed in the Born-Oppenheimer approximation. By varying the internuclear separation, potential energy curves have been constructed for the N2 and N 2 + states and compared to quantum chemistry calculations. Using these fixed-nuclei potential energy curves, and corresponding vibronic eigenenergies and eigenfunctions, a frame transformation is enacted on the fixed-nuclei scattering and dipole matrices, allowing for the calculation of vibrationally-resolved photoionization cross sections. The resultant photoionization cross sections are compared to high-resolution experimental data near threshold, a region complicated by multiple vibrationally-resolved, interacting Rydberg series.

  18. The Value of Risk Pooling for Mitigating Water Utility Financial Risks Arising From Water Scarcity

    NASA Astrophysics Data System (ADS)

    Baum, R.; Characklis, G. W.; Hughes, J.; Eskaf, S.

    2015-12-01

    Water utilities across the United States face growing supply risks as demand growth and extreme weather events make water scarcity more common. As it has become more difficult and expensive to build new supply capacity to accommodate these events, many utility managers respond by either imposing conservation measures, which reduces revenues, or acquiring additional water from other sources, which increases costs. These actions lead to changing financial trends that are difficult to predict and that utilities are currently ill-equipped to manage. As a result, adaptation strategies and tools are being developed to reduce utility vulnerabilities, ensuring both financial stability and continued access to low cost financing, a critical consideration for a capital intensive industry. Previous work in this area has involved the development of utility specific financial hedging tools. However, the time and informational requirements associated with developing these individualized strategies may be a limiting factor for widespread implementation. The objective of this research is to develop more generalized hedging instruments that can be applied simultaneously to multiple utilities across the United States, thereby increasing the potential for widespread implementation. This work first analyzes the financial risks of water scarcity for a large set of water utilities across the country and then proposes a financial hedging solution to mitigate these risks through hydrologic index-based financial insurance. Results provide insights into the most effective indices, the potential for risk pooling to reduce insurance costs, and the performance of these contracts in managing utility financial risk arising from drought.

  19. Competitive exclusion by autologous antibodies can prevent broad HIV-1 antibodies from arising

    SciTech Connect

    Luo, Shishi; Perelson, Alan S.

    2015-08-31

    The past decade has seen the discovery of numerous broad and potent monoclonal antibodies against HIV type 1 (HIV-1). Eliciting these antibodies via vaccination appears to be remarkably difficult, not least because they arise late in infection and are highly mutated relative to germline antibody sequences. Here, using a computational model, we show that broad antibodies could in fact emerge earlier and be less mutated, but that they may be prevented from doing so as a result of competitive exclusion by the autologous antibody response. We further find that this competitive exclusion is weaker in infections founded by multiple distinct strains, with broadly neutralizing antibodies emerging earlier than in infections founded by a single strain. Our computational model simulates coevolving multitype virus and antibody populations. Broadly neutralizing antibodies may therefore be easier for the adaptive immune system to generate than previously thought. As a result, if less mutated broad antibodies exist, it may be possible to elicit them with a vaccine containing a mixture of diverse virus strains.

  20. Massive nodular pseudoangiomatous stromal hyperplasia (PASH) of the breast arising simultaneously in the axilla and vulva.

    PubMed

    Jordan, Adrienne C; Jaffer, Shabnam; Mercer, Stephen E

    2011-02-01

    The authors describe a 52-year-old woman with a history of bilateral mastectomies for macromastia caused by massive nodular pseudoangiomatous stromal hyperplasia (PASH), who presented with 2 large growths in her left axilla and groin. These masses had been increasing in size for nearly a year. When excised, the axillary mass had dimensions of 14.0 × 14.0 × 5.5 cm(3) and weighed 664 g. The groin mass was slightly smaller at 14.5 × 11.0 × 5.0 cm(3) and 518 g. Microscopic examination of both masses revealed breast tissue expanded by a hyalinized stroma with prominent slit-like pseudovascular spaces, consistent with PASH. Small incidental foci of PASH are common findings in breast excisions; however, large nodular foci are rare. Furthermore, nodular foci in accessory breast tissue are exceedingly rarer and can raise clinical concerns for malignancy. Histopathologically, PASH can be mistaken for low-grade angiosarcoma. To the authors' knowledge, the present case appears to be the first description of multiple simultaneous foci of massive nodular PASH arising in accessory breast tissue. PMID:21285079

  1. Competitive exclusion by autologous antibodies can prevent broad HIV-1 antibodies from arising

    PubMed Central

    Luo, Shishi; Perelson, Alan S.

    2015-01-01

    The past decade has seen the discovery of numerous broad and potent monoclonal antibodies against HIV type 1 (HIV-1). Eliciting these antibodies via vaccination appears to be remarkably difficult, not least because they arise late in infection and are highly mutated relative to germline antibody sequences. Here, using a computational model, we show that broad antibodies could in fact emerge earlier and be less mutated, but that they may be prevented from doing so as a result of competitive exclusion by the autologous antibody response. We further find that this competitive exclusion is weaker in infections founded by multiple distinct strains, with broadly neutralizing antibodies emerging earlier than in infections founded by a single strain. Our computational model simulates coevolving multitype virus and antibody populations. Broadly neutralizing antibodies may therefore be easier for the adaptive immune system to generate than previously thought. If less mutated broad antibodies exist, it may be possible to elicit them with a vaccine containing a mixture of diverse virus strains. PMID:26324897

  2. Parathyroid adenoma arising within the sternocleidomastoid muscle: a rare complication of autotransplantation.

    PubMed

    Touska, Philip; Srikanthan, Ahgi; Amarasinghe, Kavita; Jawad, Susan

    2016-01-01

    A 19-year-old patient presented with slowly enlarging, painless, left-sided cervical mass. She had a background of multiple endocrine neoplasia 2B and had undergone a total thyroidectomy for medullary thyroid carcinoma during childhood. A cervical recurrence was therefore suspected. Ultrasonographic and MRI examination revealed a well-defined lesion within the left sternocleidomastoid muscle. Further evaluation with sestamibi and single-photon emission CT revealed elevated tracer uptake within the lesion. Cytological analysis, following ultrasound-guided sampling, revealed absent staining for calcitonin and blood samples confirmed a normal serum calcitonin level; however, the serum parathyroid hormone level was elevated. Overall, summative findings were consistent with a diagnosis of a parathyroid adenoma arising within the left sternocleidomastoid muscle. Given that this is not a location for a physiological parathyroid tissue, the adenoma might have arisen within the autotransplanted parathyroid tissue, injected into the muscular sheath during thyroidectomy. The clinical, radiological and pathological features are considered in this article. PMID:27440844

  3. Competitive exclusion by autologous antibodies can prevent broad HIV-1 antibodies from arising

    DOE PAGESBeta

    Luo, Shishi; Perelson, Alan S.

    2015-08-31

    The past decade has seen the discovery of numerous broad and potent monoclonal antibodies against HIV type 1 (HIV-1). Eliciting these antibodies via vaccination appears to be remarkably difficult, not least because they arise late in infection and are highly mutated relative to germline antibody sequences. Here, using a computational model, we show that broad antibodies could in fact emerge earlier and be less mutated, but that they may be prevented from doing so as a result of competitive exclusion by the autologous antibody response. We further find that this competitive exclusion is weaker in infections founded by multiple distinctmore » strains, with broadly neutralizing antibodies emerging earlier than in infections founded by a single strain. Our computational model simulates coevolving multitype virus and antibody populations. Broadly neutralizing antibodies may therefore be easier for the adaptive immune system to generate than previously thought. As a result, if less mutated broad antibodies exist, it may be possible to elicit them with a vaccine containing a mixture of diverse virus strains.« less

  4. Meiotic Instability of the R-R Complex Arising from Displaced Intragenic Exchange and Intrachromosomal Rearrangement

    PubMed Central

    Robbins, T. P.; Walker, E. L.; Kermicle, J. L.; Alleman, M.; Dellaporta, S. L.

    1991-01-01

    The R complex of Zea mays encodes a tissue-specific transcriptional activator of the anthocyanin pigment biosynthetic pathway. Certain R alleles comprise two genetically distinct components that confer the plant (P) and seed (S) aspects of the pigmentation pattern. These alleles are meiotically unstable, losing (P) or (S) function, often accompanied by exchange of flanking markers. We show that the (P) component consists of a single gene within the R-r complex, whereas the (S) component is part of a more complex arrangement of multiple R genes or gene subfragments. A third, cryptic region of the complex, termed (Q), consists of a truncated R sequence. The analysis of R-r crossover derivative alleles shows they arise from unequal exchange between the (P) gene and one of several distinct regions of the R-r complex. Restriction site polymorphisms were used to show that most of these unequal exchanges are intragenic. The frequency of displaced intragenic recombination is comparable to previous estimates for intragenic recombination in maize involving genes that are not duplicated. These exchange events have been used to determine the arrangement of components within the complex and their orientation in the chromosome. We also show that localized rearrangements in the (P) or (S) components are responsible for noncrossover derivative alleles. The organization of R-r has implications for these noncrossover derivatives and models for their origin are discussed. PMID:1682214

  5. Fusion of threshold rules for target detection in wireless sensor networks

    SciTech Connect

    Zhu, Mengxia; Ding, Shi-You; Brooks, Richard R; Wu, Qishi; Rao, Nageswara S

    2010-03-01

    We propose a binary decision fusion rule that reaches a global decision on the presence of a target by integrating local decisions made by multiple sensors. Without requiring a priori probability of target presence, the fusion threshold bounds derived using Chebyshev's inequality ensure a higher hit rate and lower false alarm rate compared to the weighted averages of individual sensors. The Monte Carlo-based simulation results show that the proposed approach significantly improves target detection performance, and can also be used to guide the actual threshold selection in practical sensor network implementation under certain error rate constraints.

  6. Observation of LPI Thresholds for the Nike Laser

    NASA Astrophysics Data System (ADS)

    Weaver, J. L.; Oh, J.; Afeyan, B.; Charbonneau-Lefort, M.; Phillips, L.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S.; Schmitt, A. J.; Feldman, U.; Holland, G.; Lehmberg, R. H.; McLean, E.; Manka, C.

    2008-11-01

    The Nike laser is being used to study thresholds for laser plasma instabilities (LPI) at intensities (10^15-10^16 W/cm^2) relevant to advanced implosion designs for direct drive inertial confinement fusion. The combination of short wavelength (248 nm), large bandwidth (1-2 THz), and beam smoothing by induced spatial incoherence available with this krypton-fluoride laser make these experiments unique among current facilities. This talk will present an overview of results with an emphasis on the two-plasmon decay instability (2φp). Measurements of x-rays and emission near ^1/2φo and ^3/2 φo harmonics of the laser wavelength have been collected over a wide range of intensities for both solid and foam targets. Data indicate collective multiple-angle driven excitation compatible with previous observations using solid planar targets.

  7. A random graph model of density thresholds in swarming cells.

    PubMed

    Jena, Siddhartha G

    2016-03-01

    Swarming behaviour is a type of bacterial motility that has been found to be dependent on reaching a local density threshold of cells. With this in mind, the process through which cell-to-cell interactions develop and how an assembly of cells reaches collective motility becomes increasingly important to understand. Additionally, populations of cells and organisms have been modelled through graphs to draw insightful conclusions about population dynamics on a spatial level. In the present study, we make use of analogous random graph structures to model the formation of large chain subgraphs, representing interactions between multiple cells, as a random graph Markov process. Using numerical simulations and analytical results on how quickly paths of certain lengths are reached in a random graph process, metrics for intercellular interaction dynamics at the swarm layer that may be experimentally evaluated are proposed. PMID:26893102

  8. Ultrasonic flaw detection using threshold modified S-transform.

    PubMed

    Benammar, Abdessalem; Drai, Redouane; Guessoum, Abderrezak

    2014-02-01

    Interference noising originating from the ultrasonic testing defect signal seriously influences the accuracy of the signal extraction and defect location. Time-frequency analysis methods are mainly used to improve the defects detection resolution. In fact, the S-transform, a hybrid of the Short time Fourier transform (STFT) and wavelet transform (WT), has a time frequency resolution which is far from ideal. In this paper, a new modified S-transform based on thresholding technique, which offers a better time frequency resolution compared to the original S-transform is proposed. The improvement is achieved by the introduction of a new scaling rule for the Gaussian window used in S-transform. Simulation results are presented and show correct time frequency information of multiple Gaussian echoes under low signal-to-noise ratio (SNR) environment. In addition, experimental results demonstrate better and reliable detection of close echoes drowned in the noise. PMID:24120270

  9. Electronic structure of tin oxides by electron energy loss spectroscopy and real-space multiple scattering calculations

    SciTech Connect

    Moreno, M. S.; Egerton, R.F.; Rehr, J.J.; Midgley, P.A.

    2005-01-15

    The electronic structure of the tin oxides SnO and SnO{sub 2} is studied using the fine structure of the Sn-M{sub 4,5} and oxygen K-edges measured by electron energy loss spectroscopy (EELS). The experimental results are compared with real-space multiple scattering calculations. It is observed that both edges are overlapped. The calculations reveal that the observed fine structure is due largely to the oxygen states, and that it can be used to fingerprint each phase. The calculated densities of states are similar for both compounds and suggest a covalent nature. The structures appearing within the first 10 eV above the threshold arise from a covalent mixing of mainly O 2p and Sn 5s-p. For SnO the oxygen edge is satisfactorily reproduced. Discrepancies in the predicted energy position of the features in the EELS of SnO{sub 2} are briefly discussed.

  10. Measuring Input Thresholds on an Existing Board

    NASA Technical Reports Server (NTRS)

    Kuperman, Igor; Gutrich, Daniel G.; Berkun, Andrew C.

    2011-01-01

    A critical PECL (positive emitter-coupled logic) interface to Xilinx interface needed to be changed on an existing flight board. The new Xilinx input interface used a CMOS (complementary metal-oxide semiconductor) type of input, and the driver could meet its thresholds typically, but not in worst-case, according to the data sheet. The previous interface had been based on comparison with an external reference, but the CMOS input is based on comparison with an internal divider from the power supply. A way to measure what the exact input threshold was for this device for 64 inputs on a flight board was needed. The measurement technique allowed an accurate measurement of the voltage required to switch a Xilinx input from high to low for each of the 64 lines, while only probing two of them. Directly driving an external voltage was considered too risky, and tests done on any other unit could not be used to qualify the flight board. The two lines directly probed gave an absolute voltage threshold calibration, while data collected on the remaining 62 lines without probing gave relative measurements that could be used to identify any outliers. The PECL interface was forced to a long-period square wave by driving a saturated square wave into the ADC (analog to digital converter). The active pull-down circuit was turned off, causing each line to rise rapidly and fall slowly according to the input s weak pull-down circuitry. The fall time shows up as a change in the pulse width of the signal ready by the Xilinx. This change in pulse width is a function of capacitance, pulldown current, and input threshold. Capacitance was known from the different trace lengths, plus a gate input capacitance, which is the same for all inputs. The pull-down current is the same for all inputs including the two that are probed directly. The data was combined, and the Excel solver tool was used to find input thresholds for the 62 lines. This was repeated over different supply voltages and

  11. 31 CFR 535.335 - Claim arising out of events in Iran.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Claim arising out of events in Iran... General Definitions § 535.335 Claim arising out of events in Iran. For purposes of § 535.216, a claim is one “arising out of events” of the type specified only if such event is the specific act that is...

  12. 31 CFR 535.335 - Claim arising out of events in Iran.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Claim arising out of events in Iran... General Definitions § 535.335 Claim arising out of events in Iran. For purposes of § 535.216, a claim is one “arising out of events” of the type specified only if such event is the specific act that is...

  13. 31 CFR 535.335 - Claim arising out of events in Iran.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 31 Money and Finance:Treasury 3 2011-07-01 2011-07-01 false Claim arising out of events in Iran... General Definitions § 535.335 Claim arising out of events in Iran. For purposes of § 535.216, a claim is one “arising out of events” of the type specified only if such event is the specific act that is...

  14. 31 CFR 535.335 - Claim arising out of events in Iran.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Claim arising out of events in Iran... General Definitions § 535.335 Claim arising out of events in Iran. For purposes of § 535.216, a claim is one “arising out of events” of the type specified only if such event is the specific act that is...

  15. 31 CFR 535.335 - Claim arising out of events in Iran.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 31 Money and Finance:Treasury 3 2012-07-01 2012-07-01 false Claim arising out of events in Iran... General Definitions § 535.335 Claim arising out of events in Iran. For purposes of § 535.216, a claim is one “arising out of events” of the type specified only if such event is the specific act that is...

  16. Failure management of multiple gimbal inertial systems for space shuttle

    NASA Technical Reports Server (NTRS)

    Dove, D. W.; Mckern, R. A.

    1973-01-01

    A failure detection and isolation technique for use with four gimbaled inertial measurement units (IMU) is presented. By using simulated boost and entry shuttle trajectories with specific gimbaled IMU models, failure detection thresholds are developed based on red-line life dependent requirements and warning thresholds within the red-line thresholds based on expected worst case IMU performance. Using these trajectories, established trajectory threshold, and multiple IMU models, various failure detection and isolation techniques are evaluated for application in both powered and unpowered flight phases. The adequacy of the systems for both attitude and velocity detection methods is evaluated and recommendations for space shuttle applications are made.

  17. Successive Respiratory Syncytial Virus Epidemics in Local Populations Arise from Multiple Variant Introductions, Providing Insights into Virus Persistence

    PubMed Central

    Otieno, James R.; Ngama, Mwanajuma; Mwihuri, Alexander G.; Medley, Graham F.; Cane, Patricia A.; Nokes, D. James

    2015-01-01

    ABSTRACT Respiratory syncytial virus (RSV) is a global respiratory pathogen of humans, with infection occurring characteristically as recurrent seasonal epidemics. Unlike influenza viruses, little attention has been paid to the mechanism underlying worldwide spread and persistence of RSV and how this may be discerned through an improved understanding of the introduction and persistence of RSV in local communities. We analyzed 651 attachment (G) glycoprotein nucleotide sequences of RSV B collected over 11 epidemics (2002 to 2012) in Kilifi, Kenya, and contemporaneous data collected elsewhere in Kenya and 18 other countries worldwide (2002 to 2012). Based on phylogeny, genetic distance and clustering patterns, we set out pragmatic criteria to classify local viruses into distinct genotypes and variants, identifying those newly introduced and those locally persisting. Three genotypes were identified in the Kilifi data set: BA (n = 500), SAB1 (n = 148), and SAB4 (n = 3). Recurrent RSV epidemics in the local population were composed of numerous genetic variants, most of which have been newly introduced rather than persisting in the location from season to season. Global comparison revealed that (i) most Kilifi variants do not cluster closely with strains from outside Kenya, (ii) some Kilifi variants were closely related to those observed outside Kenya (mostly Western Europe), and (iii) many variants were circulating elsewhere but were never detected in Kilifi. These results are consistent with the hypothesis that year-to-year presence of RSV at the local level (i.e., Kilifi) is achieved primarily, but not exclusively, through introductions from a pool of variants that are geographically restricted (i.e., to Kenya or to the region) rather than global. IMPORTANCE The mechanism by which RSV persists and reinvades local populations is poorly understood. We investigated this by studying the temporal patterns of RSV variants in a rural setting in tropical Africa and comparing these variants with contemporaneous variants circulating in other countries. We found that periodic seasonal RSV transmission at the local level appears to require regular new introductions of variants. However, importantly, the evidence suggests that the source of new variants is mostly geographically restricted, and we hypothesize that year-to-year RSV persistence is at the country level rather than the global level. This has implications for control. PMID:26355091

  18. cDNA sequence and heterologous expression of monomeric spinach pullulanase: multiple isomeric forms arise from the same polypeptide.

    PubMed

    Renz, A; Schikora, S; Schmid, R; Kossmann, J; Beck, E

    1998-05-01

    The spinach pullulanase gene was cloned and sequenced using peptide sequences of the purified enzyme as a starting point and employing PCR techniques and cDNA library screening. Its open reading frame codes for a protein of 964 amino acids which represents a precursor of the pullulanase. The N-terminal transit peptide consists of 65 amino acids, and the mature protein, comprising 899 amino acids, has a calculated molecular mass of 99kDa. Pullulanase is a member of the alpha-amylase family. In addition to a characteristic catalytic (beta/alpha)8-barrel domain, it contains a domain, F, that is specific for branching and debranching enzymes. Pullulanase cDNA was expressed in Escherichia coli, and the purified protein was compared with the enzyme from spinach leaves. Identity of the two proteins was confirmed in terms of catalytic properties, N-terminal amino acid sequences and molecular masses. The pullulanase produced by E. coli showed the same microheterogeneity as the spinach leaf enzyme: it could be resolved into two substrate-induced forms by electrophoresis in amylopectin-containing polyacrylamide gels, and, in the absence of substrate, into several free forms (charge isomers) by isoelectric focusing or chromatofocusing. Rechromatofocusing of single free forms resulted in the originally observed pattern of molecular forms. However, heterogeneity of the protein disappeared on isoelectric focusing under completely denaturing conditions when only one protein band was observed. Post-translational modifications such as glycosylation and phosphorylation could be excluded as potential explanations for the protein heterogeneity. Therefore the microheterogeneity of spinach leaf pullulanase results from neither genetic variation nor post-translational modifications, but is a property of the single unmodified gene product. The different interconvertible forms of the pullulanase represent protein populations of different tertiary structure of the same polypeptide. PMID:9560325

  19. Temporal discrimination threshold with healthy aging.

    PubMed

    Ramos, Vesper Fe Marie Llaneza; Esquenazi, Alina; Villegas, Monica Anne Faye; Wu, Tianxia; Hallett, Mark

    2016-07-01

    The temporal discrimination threshold (TDT) is the shortest interstimulus interval at which a subject can perceive successive stimuli as separate. To investigate the effects of aging on TDT, we studied tactile TDT using the method of limits with 120% of sensory threshold in each hand for each of 100 healthy volunteers, equally divided among men and women, across 10 age groups, from 18 to 79 years. Linear regression analysis showed that age was significantly related to left-hand mean, right-hand mean, and mean of 2 hands with R-square equal to 0.08, 0.164, and 0.132, respectively. Reliability analysis indicated that the 3 measures had fair-to-good reliability (intraclass correlation coefficient: 0.4-0.8). We conclude that TDT is affected by age and has fair-to-good reproducibility using our technique. PMID:27255827

  20. Semiclassical approaches to below-threshold harmonics

    SciTech Connect

    Hostetter, James A.; Tate, Jennifer L.; Schafer, Kenneth J.; Gaarde, Mette B.

    2010-08-15

    We study the generation of below-threshold harmonics in a model atom by extending the three-step semiclassical model of harmonic generation to include effects of the atomic potential. We explore the generalization of semiclassical trajectories of the electron in the presence of the combined laser-atom potential and calculate the intensity-dependent dipole phase associated with these trajectories. Our results are in good agreement with fully quantum mechanical calculations, as well as with recent experimental observations. We show that the so-called long trajectory readily generalizes to below-threshold harmonic generation and is relatively insensitive to the choice of initial conditions. We also find that the short trajectory can only lead to low-energy harmonics for electrons that have been released close to the ion core in a process that is closer to multiphoton than to tunnel ionization.