Science.gov

Sample records for multiple thresholds arise

  1. Optimising threshold levels for information transmission in binary threshold networks: Independent multiplicative noise on each threshold

    NASA Astrophysics Data System (ADS)

    Zhou, Bingchang; McDonnell, Mark D.

    2015-02-01

    The problem of optimising the threshold levels in multilevel threshold system subject to multiplicative Gaussian and uniform noise is considered. Similar to previous results for additive noise, we find a bifurcation phenomenon in the optimal threshold values, as the noise intensity changes. This occurs when the number of threshold units is greater than one. We also study the optimal thresholds for combined additive and multiplicative Gaussian noise, and find that all threshold levels need to be identical to optimise the system when the additive noise intensity is a constant. However, this identical value is not equal to the signal mean, unlike the case of additive noise. When the multiplicative noise intensity is instead held constant, the optimal threshold levels are not all identical for small additive noise intensity but are all equal to zero for large additive noise intensity. The model and our results are potentially relevant for sensor network design and understanding neurobiological sensory neurons such as in the peripheral auditory system.

  2. Squamous cell carcinoma arising in a multiple verrucous epidermal nevus*

    PubMed Central

    Yarak, Samira; Machado, Taila Yuri Siqueira; Ogawa, Marilia Marufuji; Almeida, Mirian Luzia da Silva; Enokihara, Milvia Maria Simões e Silva; Porro, Adriana Maria

    2016-01-01

    Verrucous epidermal nevi are hamartomatous lesions of the epidermis that, unlike other epidermal nevi (such as sebaceous nevus or nevus comedonicus), are rarely associated with malignant neoplasms. The majority of squamous cell carcinoma develop in linear or multiple epidermal nevus and rarely in solitary epidermal nevus. In general, the prognosis is favorable. We report a case of well-differentiated invasive squamous cell carcinoma arising from a multiple verrucous epidermal nevus. Although there is no consensus on prophylactic removal of epidermal nevus, its removal and biopsy should be considered if changes occur. PMID:28300931

  3. Multiple ectopic hepatocellular carcinomas arising in the abdominal cavity.

    PubMed

    Miyake, Toru; Hoshino, Seiichiro; Yoshida, Yoichiro; Aisu, Naoya; Tanimura, Syu; Hisano, Satoshi; Kuno, Nobuaki; Sohda, Tetsuro; Sakisaka, Shotaro; Yamashita, Yuichi

    2012-09-01

    Ectopic hepatocellular carcinoma (HCC) is a very rare clinical entity that is defined as HCC arising from extrahepatic liver tissue. This report presents a case of ectopic multiple HCC arising in the abdominal cavity. A 42-year-old otherwise healthy male presented with liver dysfunction at a general health checkup. Both HCV antibody and hepatitis B surface antigen were negative. Laboratory examination showed elevations in serum alpha-fetoprotein and PIVKA-II. Ultrasonography and computed tomography revealed multiple nodular lesions in the abdominal cavity with ascites without a possible primary tumor. Exploratory laparoscopy was performed, which revealed bloody ascites and multiple brown nodular tumors measuring approximately 10 mm in size that were disseminated on the perineum and mesentery. A postoperative PET-CT scan was performed but it did not reveal any evidence of a tumor in the liver. The tumors resected from the peritoneum were diagnosed as HCC. The present case of HCC was thought to have possibly developed from ectopic liver on the peritoneum or mesentery.

  4. HIV-1 Populations in Semen Arise through Multiple Mechanisms

    PubMed Central

    Dibben, Oliver; Jabara, Cassandra B.; Arney, Leslie; Kincer, Laura; Tang, Yuyang; Hobbs, Marcia; Hoffman, Irving; Kazembe, Peter; Jones, Corbin D.; Borrow, Persephone; Fiscus, Susan; Cohen, Myron S.; Swanstrom, Ronald

    2010-01-01

    HIV-1 is present in anatomical compartments and bodily fluids. Most transmissions occur through sexual acts, making virus in semen the proximal source in male donors. We find three distinct relationships in comparing viral RNA populations between blood and semen in men with chronic HIV-1 infection, and we propose that the viral populations in semen arise by multiple mechanisms including: direct import of virus, oligoclonal amplification within the seminal tract, or compartmentalization. In addition, we find significant enrichment of six out of nineteen cytokines and chemokines in semen of both HIV-infected and uninfected men, and another seven further enriched in infected individuals. The enrichment of cytokines involved in innate immunity in the seminal tract, complemented with chemokines in infected men, creates an environment conducive to T cell activation and viral replication. These studies define different relationships between virus in blood and semen that can significantly alter the composition of the viral population at the source that is most proximal to the transmitted virus. PMID:20808902

  5. HIV-1 Populations in Semen Arise through Multiple Mechanisms.

    PubMed

    Anderson, Jeffrey A; Ping, Li-Hua; Dibben, Oliver; Jabara, Cassandra B; Arney, Leslie; Kincer, Laura; Tang, Yuyang; Hobbs, Marcia; Hoffman, Irving; Kazembe, Peter; Jones, Corbin D; Borrow, Persephone; Fiscus, Susan; Cohen, Myron S; Swanstrom, Ronald

    2010-08-19

    HIV-1 is present in anatomical compartments and bodily fluids. Most transmissions occur through sexual acts, making virus in semen the proximal source in male donors. We find three distinct relationships in comparing viral RNA populations between blood and semen in men with chronic HIV-1 infection, and we propose that the viral populations in semen arise by multiple mechanisms including: direct import of virus, oligoclonal amplification within the seminal tract, or compartmentalization. In addition, we find significant enrichment of six out of nineteen cytokines and chemokines in semen of both HIV-infected and uninfected men, and another seven further enriched in infected individuals. The enrichment of cytokines involved in innate immunity in the seminal tract, complemented with chemokines in infected men, creates an environment conducive to T cell activation and viral replication. These studies define different relationships between virus in blood and semen that can significantly alter the composition of the viral population at the source that is most proximal to the transmitted virus.

  6. Multiple runoff processes and multiple thresholds control agricultural runoff generation

    NASA Astrophysics Data System (ADS)

    Saffarpour, Shabnam; Western, Andrew W.; Adams, Russell; McDonnell, Jeffrey J.

    2016-11-01

    Thresholds and hydrologic connectivity associated with runoff processes are a critical concept for understanding catchment hydrologic response at the event timescale. To date, most attention has focused on single runoff response types, and the role of multiple thresholds and flow path connectivities has not been made explicit. Here we first summarise existing knowledge on the interplay between thresholds, connectivity and runoff processes at the hillslope-small catchment scale into a single figure and use it in examining how runoff response and the catchment threshold response to rainfall affect a suite of runoff generation mechanisms in a small agricultural catchment. A 1.37 ha catchment in the Lang Lang River catchment, Victoria, Australia, was instrumented and hourly data of rainfall, runoff, shallow groundwater level and isotope water samples were collected. The rainfall, runoff and antecedent soil moisture data together with water levels at several shallow piezometers are used to identify runoff processes in the study site. We use isotope and major ion results to further support the findings of the hydrometric data. We analyse 60 rainfall events that produced 38 runoff events over two runoff seasons. Our results show that the catchment hydrologic response was typically controlled by the Antecedent Soil Moisture Index and rainfall characteristics. There was a strong seasonal effect in the antecedent moisture conditions that led to marked seasonal-scale changes in runoff response. Analysis of shallow well data revealed that streamflows early in the runoff season were dominated primarily by saturation excess overland flow from the riparian area. As the runoff season progressed, the catchment soil water storage increased and the hillslopes connected to the riparian area. The hillslopes transferred a significant amount of water to the riparian zone during and following events. Then, during a particularly wet period, this connectivity to the riparian zone, and

  7. 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.

  8. 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

  9. Threshold-limited spreading in social networks with multiple initiators

    NASA Astrophysics Data System (ADS)

    Singh, P.; Sreenivasan, S.; Szymanski, B. K.; Korniss, G.

    2013-07-01

    A classical model for social-influence-driven opinion change is the threshold model. Here we study cascades of opinion change driven by threshold model dynamics in the case where multiple initiators trigger the cascade, and where all nodes possess the same adoption threshold ϕ. Specifically, using empirical and stylized models of social networks, we study cascade size as a function of the initiator fraction p. We find that even for arbitrarily high value of ϕ, there exists a critical initiator fraction pc(ϕ) beyond which the cascade becomes global. Network structure, in particular clustering, plays a significant role in this scenario. Similarly to the case of single-node or single-clique initiators studied previously, we observe that community structure within the network facilitates opinion spread to a larger extent than a homogeneous random network. Finally, we study the efficacy of different initiator selection strategies on the size of the cascade and the cascade window.

  10. Threshold-limited spreading in social networks with multiple initiators

    PubMed Central

    Singh, P.; Sreenivasan, S.; Szymanski, B. K.; Korniss, G.

    2013-01-01

    A classical model for social-influence-driven opinion change is the threshold model. Here we study cascades of opinion change driven by threshold model dynamics in the case where multiple initiators trigger the cascade, and where all nodes possess the same adoption threshold ϕ. Specifically, using empirical and stylized models of social networks, we study cascade size as a function of the initiator fraction p. We find that even for arbitrarily high value of ϕ, there exists a critical initiator fraction pc(ϕ) beyond which the cascade becomes global. Network structure, in particular clustering, plays a significant role in this scenario. Similarly to the case of single-node or single-clique initiators studied previously, we observe that community structure within the network facilitates opinion spread to a larger extent than a homogeneous random network. Finally, we study the efficacy of different initiator selection strategies on the size of the cascade and the cascade window. PMID:23900230

  11. High Explosive Deonation Threshold Sensitivity Due to Multiple Fragment Impacts

    SciTech Connect

    Georgevich, V; Pincosy, P; Chase, J

    2004-01-07

    Fragments, bullets or projectiles can initiate a detonation in a high explosive (HE). For this to happen certain critical conditions need to be exceeded. For a given explosive, these critical conditions are the projectile velocity, the projectile size and shape, and the projectile material properties. A lot of work has been done in the area of metal shaped charge jets and individual fragments impacting the HE. One major gap in understanding initiation phenomena is the effect of multiple fragment impact. This study shows that multiple fragments can lower the fragment size and the kinetic energy thresholds.

  12. 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.

  13. Metastasizing adenocarcinoma and multiple neoplastic proliferations arising in a nevus sebaceus.

    PubMed

    Kantrow, Sara M; Ivan, Doina; Williams, Michelle D; Prieto, Victor G; Lazar, Alexander J

    2007-10-01

    Nevus sebaceus of Jadassohn is a hamartoma of multiple skin structures. Many neoplasms have been reported to arise in association with nevus sebaceus, most commonly trichoblastoma/basal cell carcinoma and syringocystadenoma papilliferum. We report a case of a 66-year-old woman with an adenocarcinoma as well as multiple neoplastic proliferations arising in a long standing nevus sebaceus on the scalp, with subsequent occipital neck metastatic disease. On histologic evaluation, the epidermis showed changes reminiscent of tumor of the follicular infundibulum as well as basaloid proliferations resembling superficial trichoblastoma. A focus suggestive of syringofibroadenoma was also present. A small dermal collection of basaloid and more mature sebocytes was consistent with a sebaceoma/sebaceous epithelioma. Most of the lesion was composed of an adenocarcinoma with areas showing ductal differentiation with decapitation secretion, well-formed papillae and focal cribriform structures. Other portions demonstrated a high-grade neoplasm with prominent nuclear atypia and a solid pattern of growth resembling high-grade breast carcinoma. Anti-epithelial membrane antigen strongly labeled tumor cells and highlighted ductal structures. Less than 1% of cells expressed progesterone or estrogen receptors. Her2/neu reactivity was focally present, showing 1+ membranous reactivity in 10% of cells. Anti-p63 labeled basaloid cells surrounding the tumor lobules. A breast primary was ruled out by clinical and radiologic examination. This report illustrates an extraordinary case of adnexal neoplasia displaying various lines of differentiation arising in association with nevus sebaceus.

  14. 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.

  15. 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

  16. Twist1 activity thresholds define multiple functions in limb development.

    PubMed

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

    2010-11-01

    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 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.

  17. 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

  18. 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.

  19. Compartmentalization in environmental science and the perversion of multiple thresholds.

    PubMed

    Burkart, W

    2000-04-17

    Nature and living organisms are separated into compartments. The self-assembly of phospholipid micelles was as fundamental to the emergence of life and evolution as the formation of DNA precursors and their self-replication. Also, modern science owes much of its success to the study of single compartments, the dissection of complex structures and event chains into smaller study objects which can be manipulated with a set of more and more sophisticated equipment. However, in environmental science, these insights are obtained at a price: firstly, it is difficult to recognize, let alone to take into account what is lost during fragmentation and dissection; and secondly, artificial compartments such as scientific disciplines become self-sustaining, leading to new and unnecessary boundaries, subtly framing scientific culture and impeding progress in holistic understanding. The long-standing but fruitless quest to define dose-effect relationships and thresholds for single toxic agents in our environment is a central part of the problem. Debating single-agent toxicity in splendid isolation is deeply flawed in view of a modern world where people are exposed to low levels of a multitude of genotoxic and non-genotoxic agents. Its potential danger lies in the unwarranted postulation of separate thresholds for agents with similar action. A unifying concept involving toxicology and radiation biology is needed for a full mechanistic assessment of environmental health risks. The threat of synergism may be less than expected, but this may also hold for the safety margin commonly thought to be a consequence of linear no-threshold dose-effect relationship assumptions.

  20. 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.

  1. Synchronous multiple colonic adenocarcinomas arising in patient with neurofibromatosis type 1

    PubMed Central

    Kim, Ik Yong; Cho, Mee Yon

    2014-01-01

    We report a case of synchronous multiple colon adenocarcinomas in a patient with neurofibromatosis type 1 (NF1). NF1 is an autosomal dominant inherited disorder and patients with NF1 have high risk for both benign and malignant tumors. However, adenocarcinomas involving the colon have rarely been reported in patients with NF1. A 61-year-old man was referred for generalized peritonitis due to descending colon perforation. Left hemicolectomy was performed and pathologic examination showed four adenocarcinomas. Peritoneal nodules were confirmed as metastatic adenocarcinoma (pT4N1M1). The patient also had clinical features compatible with NF1 such as café au lait macules, axillary freckles, neurofibromas across the body, and Lisch nodules. Upon review of the literature, colon adenocarcinoma in patients with NF1 tends to occur in males and relatively young age groups, and is associated with advanced tumor stages and multiple colon cancers. To improve treatment outcome, early colonoscopic surveillance should be considered in patients with NF1. PMID:25247170

  2. The onion skin-like organization of the septum arises from multiple embryonic origins to form multiple adult neuronal fates.

    PubMed

    Wei, B; Huang, Z; He, S; Sun, C; You, Y; Liu, F; Yang, Z

    2012-10-11

    In the past several decades, tremendous progress has been achieved through developmental studies of the central nervous system structures such as the cerebral cortex. The septum, which receives reciprocal connections from a variety of brain structures, contains diverse projection neurons but few interneurons. However, the mechanisms underlying its development remain poorly understood. Here we show that the septum is organized into an onion skin-like structure composed of five groups of neurons. These neurons are parvalbumin, choline acetyltransferase, neuronal nitric oxide synthase, calretinin and calbindin immunoreactive. Using the BrdU birth-dating method, we found that these five groups of neurons in the septum are grossly generated following an outside-in pattern. Interestingly, the distinct molecular identities of these neuronal subtypes correspond to their heterogeneous subpallial origins. Using three specific transgenic mouse lines and focal in utero electroporation of Cre-reporter plasmid, we showed that septal neurons originate from not only local progenitor regions but also neighboring progenitor regions including the medial ganglionic eminence and preoptic area. Thus, the neuronal diversity of the septum is achieved through both temporal and spatial control. Our results also suggest that multiple neuronal subtypes arrive to the septum through both radial and tangential migration. Based on these findings, we proposed a novel developmental model involving multiple spatial-temporal origins of septal neurons. This study presents new perspectives for comprehensively exploring septal functions in brain circuits.

  3. A multiple threshold method for fitting the generalized Pareto distribution to rainfall time series

    NASA Astrophysics Data System (ADS)

    Deidda, R.

    2010-12-01

    Previous studies indicate the generalized Pareto distribution (GPD) as a suitable distribution function to reliably describe the exceedances of daily rainfall records above a proper optimum threshold, which should be selected as small as possible to retain the largest sample while assuring an acceptable fitting. Such an optimum threshold may differ from site to site, affecting consequently not only the GPD scale parameter, but also the probability of threshold exceedance. Thus a first objective of this paper is to derive some expressions to parameterize a simple threshold-invariant three-parameter distribution function which assures a perfect overlapping with the GPD fitted on the exceedances over any threshold larger than the optimum one. Since the proposed distribution does not depend on the local thresholds adopted for fitting the GPD, it is expected to reflect the on-site climatic signature and thus appears particularly suitable for hydrological applications and regional analyses. A second objective is to develop and test the Multiple Threshold Method (MTM) to infer the parameters of interest by using exceedances over a wide range of thresholds applying again the concept of parameters threshold-invariance. We show the ability of the MTM in fitting historical daily rainfall time series recorded with different resolutions and with a significative percentage of heavily quantized data. Finally, we prove the supremacy of the MTM fit against the standard single threshold fit, often adopted for partial duration series, by evaluating and comparing the performances on Monte Carlo samples drawn by GPDs with different shape and scale parameters and different discretizations.

  4. 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

  5. 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

  6. Step-rate thresholds for physical activity intensity in persons with multiple sclerosis.

    PubMed

    Agiovlasitis, Stamatis; Motl, Robert W

    2014-01-01

    This study examined whether the relationship between metabolic equivalent units (METs) and step-rate is altered in persons with multiple sclerosis (MS) and developed step-rate thresholds for activity intensity for these persons. Participants were 24 persons with MS (20 women; age = 44 ± 12) and 24 healthy persons without MS (20 women; age = 41 ± 11). The MS group was divided using the 12-item MS Walking Scale (MSWS-12) into two walking impairment subgroups: (a) minimal (n = 13, MSWS-12 ≤ 12.5) and (b) mild-moderate (n = 11, MSWS-12 > 12.5). METs were measured with spirometry and step-rate with hand-tally. Step-rate, height, group, the step-rate by group interaction, and the square of step-rate significantly predicted METs. At a given height, the step-rate thresholds at 3 and 6 METs were lower for persons with minimal impairment than persons without MS and even lower for persons with mild-moderate impairment. The relationship between METs and step-rate is altered in persons with MS, lowering their step-rate thresholds for activity intensity, especially for persons with MS who have higher levels of walking impairment.

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

    PubMed Central

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

    2016-01-01

    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

  8. 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

  9. A multiple threshold method for fitting the generalized Pareto distribution and a simple representation of the rainfall process

    NASA Astrophysics Data System (ADS)

    Deidda, R.

    2010-07-01

    Previous studies indicate the generalized Pareto distribution (GPD) as a suitable distribution function to reliably describe the exceedances of daily rainfall records above a proper optimum threshold, which should be selected as small as possible to retain the largest sample while assuring an acceptable fitting. Such an optimum threshold may differ from site to site, affecting consequently not only the GPD scale parameter, but also the probability of threshold exceedance. Thus a first objective of this paper is to derive some expressions to parameterize a simple threshold-invariant three-parameter distribution function which is able to describe zero and non zero values of rainfall time series by assuring a perfect overlapping with the GPD fitted on the exceedances of any threshold larger than the optimum one. Since the proposed distribution does not depend on the local thresholds adopted for fitting the GPD, it will only reflect the on-site climatic signature and thus appears particularly suitable for hydrological applications and regional analyses. A second objective is to develop and test the Multiple Threshold Method (MTM) to infer the parameters of interest on the exceedances of a wide range of thresholds using again the concept of parameters threshold-invariance. We show the ability of the MTM in fitting historical daily rainfall time series recorded with different resolutions. Finally, we prove the supremacy of the MTM fit against the standard single threshold fit, often adopted for partial duration series, by evaluating and comparing the performances on Monte Carlo samples drawn by GPDs with different shape and scale parameters and different discretizations.

  10. Relationship between foot vibration threshold and walking and balance functions in people with Multiple Sclerosis (PwMS).

    PubMed

    Uszynski, Marcin; Purtill, Helen; Coote, Susan

    2015-01-01

    The aim of this study was to investigate the relationship between foot vibration threshold and walking and balance functions in people with Multiple Sclerosis (PwMS). The study sample consisted of 34 participants with mean age of 49.5 years (SD 11.13). Participants were able to walk independently or with an assistive device. Participants underwent vibration threshold testing using the Neurothesiometer (NT), followed by the 6 min walking test (6MWT), the Timed Up and Go test (TUG) and the Berg balance scale (BBS). We found a statistically significant relationship between foot vibration threshold and all outcome measures used. The first metatarsophalangeal joint had the strongest correlation with BBS (-0.585, p < 0.01), 6 MWT (-0.557, p < 0.01) and TUG (0.498, p < 0.01). We also found that vibration threshold scores differed between those people with MS with and without walking limitations (Mann-Whitney U test, p < 0.01 for all testing points). In conclusion, these findings confirm the relationship between foot vibration threshold and clinical measures of walking and balance in PwMS and add to literature predictive validity of foot vibration threshold. They also suggest that vibration threshold may be important to consider when identifying people in need of intervention or when evaluating the effect of rehabilitation and exercise interventions.

  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. Critical immune and vaccination thresholds for determining multiple influenza epidemic waves.

    PubMed

    Matrajt, Laura; Longini, Ira M

    2012-03-01

    Previous influenza pandemics (1918, 1957, and 1968) have all had multiple waves. The 2009 pandemic influenza A (H1N1) (pandemic H1N1) started in April 2009 and was followed, in the United States (US) and temperate Northern Hemisphere, by a second wave during the fall of 2009. The ratio of susceptible and immune individuals in a population at the end of a wave determines the potential and magnitude of a subsequent wave. As influenza vaccines are not completely protective, there was a combined immunity in the population at the beginning of 2010 (due to vaccination and due to previous natural infection), and it was uncertain if this mixture of herd immunity was enough to prevent a third wave of pandemic influenza during the winter of 2010. Motivated by this problem, we developed a mathematical deterministic two-group epidemic model with vaccination and calibrated it for the 2009 pandemic H1N1. Then, applying methods from mathematical epidemiology we developed a scheme that allowed us to determine critical thresholds for vaccine-induced and natural immunity that would prevent the spread of influenza. Finally, we estimated the level of combined immunity in the US during winter 2010. Our results suggest that a third wave was unlikely if the basic reproduction number R(0) were below 1.6, plausible if the original R(0) was 1.6, and likely if the original R(0) was 1.8 or higher. Given that the estimates for the basic reproduction number for pandemic influenza place it in the range between 1.4 and 1.6 (Bacaer and Ait Dads, 2011; Fraser et al., 2009; Munayco et al., 2009; Pourbohloul et al., 2009; Tuite et al., 2010; White et al., 2009; Yang et al., 2009), our approach accurately predicted the absence of a third wave of influenza in the US during the winter of 2010. We also used this scheme to accurately predict the second wave of pandemic influenza in London and the West Midlands, UK during the fall of 2009.

  13. 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...

  14. 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.

  15. Evaluation of Interconnect-Complexity-Aware Low-Power VLSI Design Using Multiple Supply and Threshold Voltages

    NASA Astrophysics Data System (ADS)

    Waidyasooriya, Hasitha Muthumala; Hariyama, Masanori; Kameyama, Michitaka

    This paper presents a high-level synthesis approach to minimize the total power consumption in behavioral synthesis under time and area constraints. The proposed method has two stages, functional unit (FU) energy optimization and interconnect energy optimization. In the first stage, active and inactive energies of the FUs are optimized using a multiple supply and threshold voltage scheme. Genetic algorithm (GA) based simultaneous assignment of supply and threshold voltages and module selection is proposed. The proposed GA based searching method can be used in large size problems to find a near-optimal solution in a reasonable time. In the second stage, interconnects are simplified by increasing their sharing. This is done by exploiting similar data transfer patterns among FUs. The proposed method is evaluated for several benchmarks under 90nm CMOS technology. The experimental results show that more than 40% of energy savings can be achieved by our proposed method.

  16. Multiple signaling pathways coordinate to induce a threshold response in a chordate embryo.

    PubMed

    Ohta, Naoyuki; Satou, Yutaka

    2013-01-01

    In animal development, secreted signaling molecules evoke all-or-none threshold responses of target gene transcription to specify cell fates. In the chordate Ciona intestinalis, the neural markers Otx and Nodal are induced at early embryonic stages by Fgf9/16/20 signaling. Here we show that three additional signaling molecules act negatively to generate a sharp expression boundary for neural genes. EphrinA signaling antagonizes FGF signaling by inhibiting ERK phosphorylation more strongly in epidermal cells than in neural cells, which accentuates differences in the strength of ERK activation. However, even weakly activated ERK activates Otx and Nodal transcription occasionally, probably because of the inherently stochastic nature of signal transduction processes and binding of transcription factors to target sequences. This occasional and undesirable activation of neural genes by weak residual ERK activity is directly repressed by Smad transcription factors activated by Admp and Gdf1/3-like signaling, further sharpening the differential responses of cells to FGF signaling. Thus, these signaling pathways coordinate to evoke a threshold response that delineates a sharp expression boundary.

  17. Tapping into Active Learning and Multiple Intelligences With Interactive Multimedia: A Low-Threshold Classroom Approach

    ERIC Educational Resources Information Center

    Schrand, Tom

    2008-01-01

    Educational technology is seldom used to facilitate more active student learning in the classroom. Instructors who have mastered PowerPoint, however, could just as easily learn to create simple pieces of interactive multimedia that encourage student participation in learning tasks and that appeal to multiple intelligences and learning styles.…

  18. 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…

  19. Threshold of Multiple Stick-Slip Chaos for an Archetypal Self-Excited SD Oscillator Driven by Moving Belt Friction

    NASA Astrophysics Data System (ADS)

    Li, Z. X.; Cao, Q. J.; Léger, A.

    In this paper, we investigate the multiple stick-slip chaotic motion of an archetypal self-excited smooth and discontinuous (SD) oscillator driven by moving belt friction, which is constructed with the SD oscillator and the classical moving belt. The friction force between the mass and the belt is modeled as a Coulomb friction for this system. The energy introduction or dissipation during the slip and stick modes in the system is analyzed. The analytical expressions of homoclinic orbits of the unperturbed SD oscillator are derived by using a special coordinate transformation without any pronominal truncation to retain the natural characteristics, which allows us to utilize the Melnikov’s method to obtain the chaotic thresholds of the self-excited SD oscillator in the presence of the damping and external excitation. Numerical simulations are carried out to demonstrate the multiple stick-slip dynamics of the system, which show the efficiency of the prediction for stick-slip chaos of the perturbed self-excited system. The results presented herein this paper demonstrate the complicated dynamics of stick-slip periodic solutions, multiple stick-slip chaotic solutions and also coexistence of multiple solutions for the perturbed self-excited SD oscillator.

  20. Micro-CT analysis with multiple thresholds allows detection of bone formation and resorption during ultrasound-treated fracture healing.

    PubMed

    Freeman, Theresa A; Patel, Payal; Parvizi, Javad; Antoci, Valentin; Shapiro, Irving M

    2009-05-01

    Multiple threshold algorithms applied to microcomputed tomography analysis were used to probe the effects of low-intensity pulsed ultrasound on fracture healing. Rat femurs were fractured in accordance with IACUC guidelines. Ultrasound treatment was administered daily to one femur; the contralateral bone was treated with a sham transducer. Each week for 3 weeks healing fractures were harvested and scanned by micro-CT. Remodeling activity was confirmed by evaluation of TRAP activity. Using thresholds of 331-700 and 225-330, area of cortical bone, and new bone formation, respectively, were identified, and by inference, regions of bone resorption. The increased sensitivity of this multithresholding procedure revealed that ultrasound treatment significantly increased the rate of fracture healing in vivo by activating both new bone formation and by increasing the removal of cortical bone in a time- and site-specific manner. At week 1, compared to the proximal side, there was a significant increase in new bone formation distal to the fracture site. Removal of the existing cortical bone followed the same pattern at week 2. Results of the study indicate that at sites of bone turnover, this multithresholding analytical technique can be used to provide quantitative information on bone formation, as well as resorption.

  1. Corneal epithelial injury thresholds for multiple-pulse exposures to erbium fiber laser radiation at 1.54 μm

    NASA Astrophysics Data System (ADS)

    McCally, Russell L.

    2005-04-01

    Corneal epithelial damage thresholds for exposures to sequences of pulses of 1.54 μm infrared radiation produced by an Er fiber laser were investigated. Thresholds were determined for sequences of 8 to 128 pulses at a repetition frequency of 10 Hz and 8 to 256 pulses at 20 Hz. The duration of the individual pulses was 0.025 sec and the 1/e diameter of the laser beam was 0.1 cm. The results show that threshold damage is correlated by an empirical power law of the form Hth = CN-β, where Hth is the threshold radiant exposure per pulse, and N is the number of pulses. The constant C is different for the 10 Hz and 20 Hz exposures and, for both cases, is greater than the estimated threshold for a single 0.025 sec pulse. Thus the empirical power law breaks down for small numbers of pulses (viz., N< 8), where it overestimates the damage thresholds. Temperature calculations for the threshold exposure conditions show that a critical temperature model also correlates the multiple-pulse injury thresholds.

  2. Adenocarcinoma arising in multiple hyperplastic polyps in a patient with Helicobacter pylori infection and hypergastrinemia during long-term proton pump inhibitor therapy.

    PubMed

    Anjiki, Hajime; Mukaisho, Ken-Ichi; Kadomoto, Yu; Doi, Hisakazu; Yoshikawa, Kunio; Nakayama, Takahisa; Vo, Diem Thi-Ngoc; Hattori, Takanori; Sugihara, Hiroyuki

    2017-04-01

    We report a case of developing multiple adenocarcinoma foci in multiple hyperplastic polyps in a patient with Helicobacter pylori infection and hypergastrinemia during long-term proton pump inhibitor (PPI) therapy. A 57-year-old man, who was undergoing hemodialysis for chronic renal failure, underwent an upper gastrointestinal endoscopy to elucidate the cause of anemia. Atrophic gastritis with H. pylori infection and multiple adenocarcinoma foci in multiple hyperplastic polyps were found in the endoscopic and histological examinations. Enterochromaffin-like micronests and parietal cell protrusion in the background of the polyps suggested the existence of hypergastrinemia. The serum gastrin level was markedly high-10,206 pg/ml (normal range 37-172 pg/ml). The cause of this marked hypergastrinemia was not autoimmune gastritis and gastrinoma. After discontinuing PPI therapy and successful eradication of H. pylori, the serum gastrin level decreased to normal range. These findings indicate that hypergastrinemia may be caused by long-term PPI therapy in patients with H. pylori infection. This case suggests that hypergastrinemia may mediate gastric carcinogenesis in patients with H. pylori infection.

  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. Acquired savolitinib resistance in non-small cell lung cancer arises via multiple mechanisms that converge on MET-independent mTOR and MYC activation

    PubMed Central

    Castriotta, Lillian; Ladd, Brendon; Markovets, Aleksandra; Beran, Garry; Ren, Yongxin; Zhou, Feng; Adam, Ammar; Zinda, Michael; Reimer, Corinne; Qing, Weiguo; Su, Weiguo; Clark, Edwin; D'Cruz, Celina M.; Schuller, Alwin G.

    2016-01-01

    Lung cancer is the most common cause of cancer death globally with a significant, unmet need for more efficacious treatments. The receptor tyrosine kinase MET has been implicated as an oncogene in numerous cancer subtypes, including non-small cell lung cancer (NSCLC). Here we explore the therapeutic potential of savolitinib (volitinib, AZD6094, HMPL-504), a potent and selective MET inhibitor, in NSCLC. In vitro, savolitinib inhibits MET phosphorylation with nanomolar potency, which correlates with blockade of PI3K/AKT and MAPK signaling as well as MYC down-regulation. In vivo, savolitinib causes inhibition of these pathways and significantly decreases growth of MET-dependent xenografts. To understand resistance mechanisms, we generated savolitinib resistance in MET-amplified NSCLC cell lines and analyzed individual clones. We found that upregulation of MYC and constitutive mTOR pathway activation is a conserved feature of resistant clones that can be overcome by knockdown of MYC or dual mTORC1/2 inhibition. Lastly, we demonstrate that mechanisms of resistance are heterogeneous, arising via a switch to EGFR dependence or by a requirement for PIM signaling. This work demonstrates the efficacy of savolitinib in NSCLC and characterizes acquired resistance, identifying both known and novel mechanisms that may inform combination strategies in the clinic. PMID:27472392

  5. 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

  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. Metachronous multiple carcinomas arising at a colostomy site 15 years after abdominoperineal resection: a case report and review of Japanese literature.

    PubMed

    Okamoto, Norihiro; Maeda, Koutarou; Hanai, Tsunekazu; Sato, Harunobu; Masumori, Kouji; Katsuno, Hidetoshi; Maruta, Morito

    2009-01-01

    Metachronous multiple carcinomas at the site of a stoma is a rare condition after surgery. A 67-year-old man with a second tumor at the stoma site 15 years after abdominoperineal resection for rectal carcinoma is reported herein with a review of the Japanese literature. The patient visited our hospital 20 years after initial surgery, presenting with constipation and increasing tumor size in the stoma. A biopsy specimen of the tumor revealed adenocarcinoma. Block resection of the sigmoid colon and colostomy with the adjacent abdominal wall was performed. Histopathological examination showed a well-differentiated adenocarcinoma in the stoma invading the adjacent skin. A median of 144 months from the initial operation was documented in 23 cases reported.

  8. Association of Odor Thresholds and Responses in Cerebral Blood Flow of the Prefrontal Area during Olfactory Stimulation in Patients with Multiple Chemical Sensitivity

    PubMed Central

    Uchiyama, Iwao; Tanigawa, Mari; Bamba, Ikuko; Azuma, Michiyo; Takano, Hirohisa; Yoshikawa, Toshikazu; Sakabe, Kou

    2016-01-01

    Multiple chemical sensitivity (MCS) is a disorder characterized by nonspecific and recurrent symptoms from various organ systems associated with exposure to low levels of chemicals. Patients with MCS process odors differently than controls do. Previously, we suggested that this odor processing was associated with increased regional cerebral blood flow (rCBF) in the prefrontal area during olfactory stimulation using near-infrared spectroscopic (NIRS) imaging. The aim of this study was to investigate the association of odor thresholds and changes in rCBF during olfactory stimulation at odor threshold levels in patients with MCS. We investigated changes in the prefrontal area using NIRS imaging and a T&T olfactometer during olfactory stimulation with two different odorants (sweet and fecal) at three concentrations (zero, odor recognition threshold, and normal perceived odor level) in 10 patients with MCS and six controls. The T&T olfactometer threshold test and subjective assessment of irritating and hedonic odors were also performed. The results indicated that the scores for both unpleasant and pungent odors were significantly higher for those for sweet odors at the normal perceived level in patients with MCS than in controls. The brain responses at the recognition threshold (fecal odor) and normal perceived levels (sweet and fecal odors) were stronger in patients with MCS than in controls. However, significant differences in the odor detection and recognition thresholds and odor intensity score between the two groups were not observed. These brain responses may involve cognitive and memory processing systems during past exposure to chemicals. Further research regarding the cognitive features of sensory perception and memory due to past exposure to chemicals and their associations with MCS symptoms is needed. PMID:27936122

  9. Dynamic Multiple-Threshold Call Admission Control Based on Optimized Genetic Algorithm in Wireless/Mobile Networks

    NASA Astrophysics Data System (ADS)

    Wang, Shengling; Cui, Yong; Koodli, Rajeev; Hou, Yibin; Huang, Zhangqin

    Due to the dynamics of topology and resources, Call Admission Control (CAC) plays a significant role for increasing resource utilization ratio and guaranteeing users' QoS requirements in wireless/mobile networks. In this paper, a dynamic multi-threshold CAC scheme is proposed to serve multi-class service in a wireless/mobile network. The thresholds are renewed at the beginning of each time interval to react to the changing mobility rate and network load. To find suitable thresholds, a reward-penalty model is designed, which provides different priorities between different service classes and call types through different reward/penalty policies according to network load and average call arrival rate. To speed up the running time of CAC, an Optimized Genetic Algorithm (OGA) is presented, whose components such as encoding, population initialization, fitness function and mutation etc., are all optimized in terms of the traits of the CAC problem. The simulation demonstrates that the proposed CAC scheme outperforms the similar schemes, which means the optimization is realized. Finally, the simulation shows the efficiency of OGA.

  10. 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

  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.

  12. 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.

  13. 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.

  14. Brain MRI lesion load quantification in multiple sclerosis: a comparison between automated multispectral and semi-automated thresholding computer-assisted techniques.

    PubMed

    Achiron, Anat; Gicquel, Sebastien; Miron, Shmuel; Faibel, Meir

    2002-12-01

    Brain magnetic resonance imaging (MRI) lesion volume measurement is an advantageous tool for assessing disease burden in multiple sclerosis (MS). We have evaluated two computer-assisted techniques: MSA multispectral automatic technique that is based on bayesian classification of brain tissue and NIH image analysis technique that is based on local (lesion by lesion) thresholding, to establish reliability and repeatability values for each technique. Brain MRIs were obtained for 30 clinically definite relapsing-remitting MS patients using a 2.0 Tesla MR scanner with contiguous, 3 mm thick axial, T1, T2 and PD weighted modalities. Digital (Dicom 3) images were analyzed independently by three observers; each analyzed the images twice, using the two different techniques (Total 360 analyses). Accuracy of lesion load measurements using phantom images of known volumes showed significantly better results for the MSA multispectral technique (p < 0.001). The mean intra-and inter-observer variances were, respectively, 0.04 +/- 0.4 (range 0.04-0.13), and 0.09 +/- 0.6 (range 0.01-0.26) for the multispectral MSA analysis technique, 0.24 +/- 2.27 (range 0.23-0.72) and 0.33 +/- 3.8 (range 0.47-1.36) for the NIH threshold technique. These data show that the MSA multispectral technique is significantly more accurate in lesion volume measurements, with better results of within and between observers' assessments, and the lesion load measurements are not influenced by increased disease burden. Measurements by the MSA multispectral technique were also faster and decreased analysis time by 43%. The MSA multispectral technique is a promising tool for evaluating MS patients. Non-biased recognition and delineation algorithms enable high accuracy, low intra-and inter-observer variances and fast assessment of MS related lesion load.

  15. Comparison of repeatability and multiple trait threshold models for litter size in sheep using observed and simulated data in Bayesian analyses.

    PubMed

    Mekkawy, W; Roehe, R; Lewis, R M; Davies, M H; Bünger, L; Simm, G; Haresign, W

    2010-08-01

    Bayesian analyses were used to estimate genetic parameters on 5580 records of litter size in the first four parities from 1758 Mule ewes. To examine the appropriateness of fitting repeatability (RM) or multiple trait threshold models (MTM) to litter size of different parities, both models were used to estimate genetic parameters on the observed data and were thereafter compared in a simulation study. Posterior means of the heritabilities of litter size in different parities using a MTM ranged from 0.12 to 0.18 and were higher than the heritability based on the RM (0.08). Posterior means of the genetic correlations between litter sizes of different parities were positive and ranged from 0.24 to 0.71. Data sets were simulated based on the same pedigree structure and genetic parameters of the Mule ewe population obtained from both models. The simulation showed that the relative loss in accuracy and increase in mean squared error (MSE) was substantially higher when using the RM, given that the parameters estimated from the observed data using the opposite model are the true parameters. In contrast, Bayesian information criterion (BIC) selected the RM as most appropriate model given the data because of substantial penalty for the higher number of parameters to be estimated in the MTM model. In conclusion, when the relative change in accuracy and MSE is of main interest for estimation of breeding values of litter size of different parities, the MTM is recommended for the given population. When reduction in risk of using the wrong model is the main aim, the BIC suggest that the RM is the most appropriate model.

  16. Low-threshold stimulated emission at 249 nm and 256 nm from AlGaN-based multiple-quantum-well lasers grown on sapphire substrates

    SciTech Connect

    Li, Xiao-Hang; Detchprohm, Theeradetch; Kao, Tsung-Ting; Satter, Md. Mahbub; Shen, Shyh-Chiang; Douglas Yoder, P.; Dupuis, Russell D.; Wang, Shuo; Wei, Yong O.; Xie, Hongen; Fischer, Alec M.; Ponce, Fernando A.; Wernicke, Tim; Reich, Christoph; Martens, Martin; Kneissl, Michael

    2014-10-06

    Optically pumped deep-ultraviolet (DUV) lasing with low threshold was demonstrated from AlGaN-based multiple-quantum-well (MQW) heterostructures grown on sapphire substrates. The epitaxial layers were grown pseudomorphically by metalorganic chemical vapor deposition on (0001) sapphire substrates. Stimulated emission was observed at wavelengths of 256 nm and 249 nm with thresholds of 61 kW/cm{sup 2} and 95 kW/cm{sup 2} at room temperature, respectively. The thresholds are comparable to the reported state-of-the-art AlGaN-based MQW DUV lasers grown on bulk AlN substrates emitting at 266 nm. These low thresholds are attributed to the optimization of active region and waveguide layer as well as the use of high-quality AlN/sapphire templates. The stimulated emission above threshold was dominated by transverse-electric polarization. This work demonstrates the potential candidacy of sapphire substrates for DUV diode lasers.

  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. Threshold Graph Limits and Random Threshold Graphs

    PubMed Central

    Diaconis, Persi; Holmes, Susan; Janson, Svante

    2010-01-01

    We study the limit theory of large threshold graphs and apply this to a variety of models for random threshold graphs. The results give a nice set of examples for the emerging theory of graph limits. PMID:20811581

  19. 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

  20. Identifying Threshold Concepts in the Careers of Educational Developers

    ERIC Educational Resources Information Center

    Timmermans, Julie A.

    2014-01-01

    The purpose of this multiple case study was to identify threshold concepts in the careers of educational developers. Twenty-one common threshold concepts emerged, with one threshold concept common among all participants: Facilitating a change process. The remaining 20 threshold concepts were captured in the following three categories: (1) Ways of…

  1. 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).

  2. 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.

  3. Papillary serous carcinoma arising from adenomyosis presenting as intramural leiomyoma.

    PubMed

    Izadi-Mood, Narges; Samadi, Nasrin; Sarmadi, Soheila; Eftekhar, Zahra

    2007-04-01

    Adenocarcinoma arising from adenomyosis uteri is rare. Herein, we reported a patient with papillary serous carcinoma arising from adenomyosis. The patient was a 61-year-old woman who received tamoxifen for treatment of her breast cancer over the past five years. In hysterectomy specimen taken for investigating her uncontrolled bleeding with suspicion of uterine myoma, multiple adenomyotic foci were found in the uterine wall. In one of these foci, papillary serous carcinoma was found. No evidence of tumor was seen in endometrial surface, peritoneum, and both adnexa.

  4. On the measurement of laser-induced plasma breakdown thresholds

    SciTech Connect

    Brieschenk, Stefan; Kleine, Harald; O'Byrne, Sean

    2013-09-07

    The breakdown threshold of a gas exposed to intense laser-radiation is a function of gas and laser properties. Breakdown thresholds reported in the literature often vary greatly and these differences can partially be traced back to the method that is typically used to determine breakdown thresholds. This paper discusses the traditional method used to determine breakdown thresholds and the potential errors that can arise using this approach, and presents an alternative method which can yield more accurate data especially when determining breakdown thresholds as functions of gas pressure.

  5. 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…

  6. Synchronous melanomas arising within nevus spilus*

    PubMed Central

    de Brito, Maria Helena Toda Sanches; Dionísio, Cecília Silva Nunes de Moura; Fernandes, Cândida Margarida Branco Martins; Ferreira, Joana Cintia Monteiro; Rosa, Maria Joaninha Madalena de Palma Mendonça da Costa; Garcia, Maria Manuela Antunes Pecegueiro da Silva

    2017-01-01

    Nevus spilus is a melanocytic cutaneous lesion consisting of a light brown background macule with numerous superimposed darker maculopapular speckles. Melanoma arising from a nevus spilus is rare, with less than 40 cases reported to date. The absolute risk for malignant transformation is not well defined, lacking a standardized management approach. We report a new case of melanoma arising from nevus spilus, with the additional peculiarity of multifocality. We offer our recommendations for the management of the condition. PMID:28225967

  7. Synchronous melanomas arising within nevus spilus.

    PubMed

    Brito, Maria Helena Toda Sanches de; Dionísio, Cecília Silva Nunes de Moura; Fernandes, Cândida Margarida Branco Martins; Ferreira, Joana Cintia Monteiro; Rosa, Maria Joaninha Madalena de Palma Mendonça da Costa; Garcia, Maria Manuela Antunes Pecegueiro da Silva

    2017-01-01

    Nevus spilus is a melanocytic cutaneous lesion consisting of a light brown background macule with numerous superimposed darker maculopapular speckles. Melanoma arising from a nevus spilus is rare, with less than 40 cases reported to date. The absolute risk for malignant transformation is not well defined, lacking a standardized management approach. We report a new case of melanoma arising from nevus spilus, with the additional peculiarity of multifocality. We offer our recommendations for the management of the condition.

  8. HRS Threshold Adjustment Test

    NASA Astrophysics Data System (ADS)

    Skapik, Joe

    1991-07-01

    This test will determine the optimal, non-standard discriminator thresholds for the few anomalous channels on each HRS detector. A 15 second flat field observation followed by a 210 second dark count is performed at each of 10 discriminator threshold values for each detector. The result of the test will be the optimal threshold values to be entered into the PDB. Edited 4/30/91 to add comments to disable/re-enable cross-talk tables.

  9. 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.

  10. 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.

  11. Theory of Threshold Fluctuations in Nerves

    PubMed Central

    Lecar, Harold; Nossal, Ralph

    1971-01-01

    Threshold fluctuations in axon firing can arise as a result of electrical noise in the excitable membrane. A general theoretical expression for the fluctuations is applied to the analysis of three sources of membrane noise: Johnson noise, excess 1/f noise, and sodium conductance fluctuations. Analytical expressions for the width of the firing probability curve are derived for each of these noise sources. Specific calculations are performed for the node of Ranvier of the frog, and attention is given to the manner in which threshold fluctuations are affected by variations of temperature, ion concentrations, and the application of various drugs. Comparison with existing data suggests that threshold fluctuations can best be explained by sodium conductance fluctuations. Additional experiments directed at distinguishing among the various noise sources are proposed. PMID:5167401

  12. 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…

  13. Squamous cell carcinoma arising in a meningomyelocele.

    PubMed Central

    Saksun, J. M.; Fisher, B. K.

    1978-01-01

    Squamous cell carcinoma developed in the meningomyelocele of a 25-year-old man. This is the third such case reported. The possibility of malignant disease arising in this congenital defect must be taken into account when treatment is being considered. Images FIG. 1 FIG. 2 FIG. 3 PMID:709475

  14. 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.

  15. 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.

  16. Double Photoionization Near Threshold

    NASA Technical Reports Server (NTRS)

    Wehlitz, Ralf

    2007-01-01

    The threshold region of the double-photoionization cross section is of particular interest because both ejected electrons move slowly in the Coulomb field of the residual ion. Near threshold both electrons have time to interact with each other and with the residual ion. Also, different theoretical models compete to describe the double-photoionization cross section in the threshold region. We have investigated that cross section for lithium and beryllium and have analyzed our data with respect to the latest results in the Coulomb-dipole theory. We find that our data support the idea of a Coulomb-dipole interaction.

  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.

  19. Gelatin-Graphene Nanocomposites with Ultralow Electrical Percolation Threshold.

    PubMed

    Nassira, Hoda; Sánchez-Ferrer, Antoni; Adamcik, Jozef; Handschin, Stephan; Mahdavi, Hossein; Taheri Qazvini, Nader; Mezzenga, Raffaele

    2016-08-01

    Gelatin-graphene conductive biopolymer nanocomposites (CPCs) with ultralow percolation threshold are designed by reducing in situ graphene oxide nanosheets with ascorbic acid and suppressing the aggregation of the graphene nanosheets. The resulting conductive nanocomposites show a record-low electrical percolation threshold of 3.3 × 10(-2) vol%, which arises from the homogeneous dispersion of the graphene nanosheets within the gelatin matrix.

  20. Threshold-avoiding proteomics pipeline.

    PubMed

    Suits, Frank; Hoekman, Berend; Rosenling, Therese; Bischoff, Rainer; Horvatovich, Peter

    2011-10-15

    We present a new proteomics analysis pipeline focused on maximizing the dynamic range of detected molecules in liquid chromatography-mass spectrometry (LC-MS) data and accurately quantifying low-abundance peaks to identify those with biological relevance. Although there has been much work to improve the quality of data derived from LC-MS instruments, the goal of this study was to extend the dynamic range of analyzed compounds by making full use of the information available within each data set and across multiple related chromatograms in an experiment. Our aim was to distinguish low-abundance signal peaks from noise by noting their coherent behavior across multiple data sets, and central to this is the need to delay the culling of noise peaks until the final peak-matching stage of the pipeline, when peaks from a single sample appear in the context of all others. The application of thresholds that might discard signal peaks early is thereby avoided, hence the name TAPP: threshold-avoiding proteomics pipeline. TAPP focuses on quantitative low-level processing of raw LC-MS data and includes novel preprocessing, peak detection, time alignment, and cluster-based matching. We demonstrate the performance of TAPP on biologically relevant sample data consisting of porcine cerebrospinal fluid spiked over a wide range of concentrations with horse heart cytochrome c.

  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. Cellular neurothekeomas arising on a café-au-lait macule.

    PubMed

    Hernández-Martín, Angela; Colmenero, Isabel; Torrelo, Antonio

    2011-01-01

    Neurothekeoma is a tumor probably derived from the nerve sheath, which usually appears during the first 2 decades of life as a solitary papule or nodule; multiple neurothekeomas are very unusual. We present a case of multiple cellular neurothekeomas arising on a café-au-lait macule in a child, a situation that has not been reported to our knowledge.

  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. 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

  5. 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

  6. Glomangiosarcoma Arising from a Prior Biopsy Site

    PubMed Central

    Maselli, Amy M.; Jambhekar, Amani V.

    2017-01-01

    Summary: Glomangiosarcoma represents a rare malignant variant of the benign glomus tumor that typically presents as a tender, slowly growing nodule with a predilection for the lower extremities. Unlike their benign counterparts, glomangiosarcomas may display aggressive characteristics such as large size, local invasion, and a tendency to recur after excision. Although wide local excision remains the treatment of choice, rare cases of systemic metastasis have been previously reported. We present a case of glomangiosarcoma arising at a prior biopsy site after excision of an unknown soft tissue lesion. PMID:28203514

  7. Potency matters: thresholds govern endocrine activity.

    PubMed

    Borgert, Christopher J; Baker, Stephen P; Matthews, John C

    2013-10-01

    Whether thresholds exist for endocrine active substances and for endocrine disrupting effects of exogenous chemicals has been posed as a question for regulatory policy by the European Union. This question arises from a concern that the endocrine system is too complex to allow estimations of safe levels of exposure to any chemical with potential endocrine activity, and a belief that any such chemical can augment, retard, or disrupt the normal background activity of endogenous hormones. However, vital signaling functions of the endocrine system require it to continuously discriminate the biological information conveyed by potent endogenous hormones from a more concentrated background of structurally similar, endogenous molecules with low hormonal potential. This obligatory ability to discriminate important hormonal signals from background noise can be used to define thresholds for induction of hormonal effects, without which normal physiological functions would be impossible. From such thresholds, safe levels of exposure can be estimated. This brief review highlights how the fundamental principles governing hormonal effects - affinity, efficacy, potency, and mass action - dictate the existence of thresholds and why these principles also define the potential that exogenous chemicals might have to interfere with normal endocrine functioning.

  8. Leiomyosarcoma arising from the inferior mesenteric vein

    PubMed Central

    Clemente, Gennaro; Sarno, Gerardo; Barbaro, Brunella; Nuzzo, Gennaro

    2009-01-01

    Leyomiosarcomas arising from the portal/mesenteric venous system are very rare tumours, and only a few cases have been reported in the global literature. As the other leyomiosarcomas of vascular origin, they are associated with a poor prognosis. The present report describes the case of a 66-year-old woman with a leyomiosarcoma of the inferior mesenteric vein, unexpectedly found during a CT scan performed for another indication. A brief review of the literature is also given. The patient underwent radical surgical excision and enjoys a good health, without radiological signs of recurrence, 24 months after surgery. In this case, an early incidental diagnosis determined an early treatment and, probably, a favourable prognosis. This is the second case of leyomiosarcoma of the inferior mesenteric vein reported in the literature. PMID:21686492

  9. Microbial diversity arising from thermodynamic constraints

    PubMed Central

    Großkopf, Tobias; Soyer, Orkun S

    2016-01-01

    The microbial world displays an immense taxonomic diversity. This diversity is manifested also in a multitude of metabolic pathways that can utilise different substrates and produce different products. Here, we propose that these observations directly link to thermodynamic constraints that inherently arise from the metabolic basis of microbial growth. We show that thermodynamic constraints can enable coexistence of microbes that utilise the same substrate but produce different end products. We find that this thermodynamics-driven emergence of diversity is most relevant for metabolic conversions with low free energy as seen for example under anaerobic conditions, where population dynamics is governed by thermodynamic effects rather than kinetic factors such as substrate uptake rates. These findings provide a general understanding of the microbial diversity based on the first principles of thermodynamics. As such they provide a thermodynamics-based framework for explaining the observed microbial diversity in different natural and synthetic environments. PMID:27035705

  10. The relative stability of black hole threshold solutions in gravitational collapse

    NASA Astrophysics Data System (ADS)

    Brasoveanu, Theodor; Pretorius, Frans

    2012-03-01

    We present numerical studies of the relative stability of critical solutions in problems of gravitational collapse. These strong-field solutions to Einstein equations, initially discovered by M. Choptuik, arise at the threshold of black hole formation. We study the evolution of systems with multiple matter sources (such as scalar or Yang-Mills fields) that exhibit the same type of threshold solution when studied individually and only interact with each other gravitationally. Given the unstable nature of critical solutions, the central question that we address is how does matter of one type behave in the presence of a critical solution of another type of matter. Preliminary results, using adaptive grid techniques to solve Einstein equations coupled to matter, indicate that the near-critical solution of the combined system seems to switch from one type of threshold to another, as the critical point is approached in parameter space. The overall dynamics (exhibiting time-periodicity or self-similarity) depends on the relative amounts of energy present in the system and on the overlapping region of the fields.

  11. 32 CFR 536.112 - Settlement authority for claims arising under international agreements (for those claims arising...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Settlement authority for claims arising under international agreements (for those claims arising in the United States). 536.112 Section 536.112 National... arising under international agreements (for those claims arising in the United States)....

  12. 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.

  13. 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.

  14. Vision thresholds revisited

    NASA Astrophysics Data System (ADS)

    Garstang, R. H.

    1999-05-01

    During and just after World War II there was intense interest in the threshold for seeing faint sources against illuminated backgrounds. Knoll, Tousey and Hulburt (1946, 1948) determined the threshold for (effectively) point sources seen against backgrounds ranging in brightness from darkness to subdued daylight. Blackwell (1946) gave contrast ratios for sources of various sizes ranging from point sources up to circular disks of 6 degrees diameter, all seen against the same range of brightnesses, and determined by a very large number of visual observations made by a team of observers. I have combined the two sets of results, and represented them by an improvement on the theoretical formula for threshold illuminance as a function of background brightness which was suggested by Hecht (1934). My formula agrees very well with the observations, and is very suitable for incorporation into computer programs. Applications have been made to problems where the background brightness is caused by light pollution, and the source size is determined by the seeing. These include the optimum magnification and limiting magnitude of telescopes, and the analysis of visual limiting magnitudes determined by Bowen (1947) to determine the night sky brightness at Mount Wilson in 1947.

  15. Double threshold behavior in a resonance-controlled ZnO random laser

    NASA Astrophysics Data System (ADS)

    Niyuki, Ryo; Fujiwara, Hideki; Nakamura, Toshihiro; Ishikawa, Yoshie; Koshizaki, Naoto; Tsuji, Takeshi; Sasaki, Keiji

    2017-03-01

    We observed unusual lasing characteristics, such as double thresholds and blue-shift of lasing peak, in a resonance-controlled ZnO random laser. From the analysis of lasing threshold carrier density, we found that the lasing at 1st and 2nd thresholds possibly arises from different mechanisms; the lasing at 1st threshold involves exciton recombination, whereas the lasing at 2nd threshold is caused by electron-hole plasma recombination, which is the typical origin of conventional random lasers. These phenomena are very similar to the transition from polariton lasing to photon lasing observed in a well-defined cavity laser.

  16. Fibrous dysplasia arising from the calcaneus.

    PubMed

    Isefuku, S; Hatori, M; Ehara, S; Hosaka, M; Ito, K; Kokubun, S

    1999-11-01

    A case of an 18-year-old woman with fibrous dysplasia arising in the calcaneus, which is extremely rare, is reported, with the emphasis placed on differential diagnosis from low-grade central osteosarcoma. She had a severe pain in her left ankle after sprain. Plain radiographs showed a radiolucent lesion measuring 6.3 x 2.5 cm with a sclerotic margin in the left calcaneus. CT scans showed a well-defined lytic lesion with disruption of the lateral cortex and an ossification or calcification in its center. On MR imaging, the lesion had isointensities and high intensities on T1 and T2 weighted images, respectively, but its central portions showed lower intensities both on T1 and T2 weighted images. The lesion was enhanced with gadolinium except for the central portions. The specimen obtained by open biopsy consisted of fibrous tissue and foci of irregular woven bone. None of the nuclear atypia, mitoses, longitudinal stream of bone or invasive nature of growth was detected. The diagnosis of fibrous dysplasia was histologically made. The lesion was curetted and packed with autogenous bone chips. No evidence of recurrence was noted postoperatively.

  17. 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.

  18. [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.

  19. Threshold Concepts in Research Education and Evidence of Threshold Crossing

    ERIC Educational Resources Information Center

    Kiley, Margaret; Wisker, Gina

    2009-01-01

    Most work on threshold concepts has hitherto related to discipline-specific undergraduate education, however, the idea of generic doctoral-level threshold concepts appeared to us to provide a strong and useful framework to support research learning and teaching at the graduate level. The early work regarding research-level threshold concepts is…

  20. Cost-effectiveness thresholds: pros and cons.

    PubMed

    Bertram, Melanie Y; Lauer, Jeremy A; De Joncheere, Kees; Edejer, Tessa; Hutubessy, Raymond; Kieny, Marie-Paule; Hill, Suzanne R

    2016-12-01

    Cost-effectiveness analysis is used to compare the costs and outcomes of alternative policy options. Each resulting cost-effectiveness ratio represents the magnitude of additional health gained per additional unit of resources spent. Cost-effectiveness thresholds allow cost-effectiveness ratios that represent good or very good value for money to be identified. In 2001, the World Health Organization's Commission on Macroeconomics in Health suggested cost-effectiveness thresholds based on multiples of a country's per-capita gross domestic product (GDP). In some contexts, in choosing which health interventions to fund and which not to fund, these thresholds have been used as decision rules. However, experience with the use of such GDP-based thresholds in decision-making processes at country level shows them to lack country specificity and this - in addition to uncertainty in the modelled cost-effectiveness ratios - can lead to the wrong decision on how to spend health-care resources. Cost-effectiveness information should be used alongside other considerations - e.g. budget impact and feasibility considerations - in a transparent decision-making process, rather than in isolation based on a single threshold value. Although cost-effectiveness ratios are undoubtedly informative in assessing value for money, countries should be encouraged to develop a context-specific process for decision-making that is supported by legislation, has stakeholder buy-in, for example the involvement of civil society organizations and patient groups, and is transparent, consistent and fair.

  1. Optical thresholding and Max Operation

    DTIC Science & Technology

    Thresholding and Max operations are essential elements in the implementation of neural networks. Although there have been several optical...implementations of neural networks, the thresholding functions are performed electronically. Optical thresholding and Max operations have the advantages of...we propose and study the properties of self-oscillation in nonlinear optical (NLO) four-wave mixing (FWM) and NLO resonators for parallel optical thresholding and Max operation.

  2. State changes arising from wind transport in drylands (Invited)

    NASA Astrophysics Data System (ADS)

    Okin, G. S.; D'Odorico, P.

    2013-12-01

    The importance of soil transport due to wind has been increasingly understood as a crucial aspect of ecosystem evolution in drylands. Aeolian processes impact vegetation structure, topographic characteristics, and soil properties, and aeolian transport drives important feedbacks that give rise to multiple stable states. Here, we outline the results of several field and modeling experiments that show the critical interactions that occur amongst wind, vegetation, and soils. Measurements of transport, fallout radionuclide tracing, deposition, and vegetation growth shows clearly that aeolian transport can result in significant alteration of a variety of ecosystem and soil factors. Moreover, changes to vegetation and soils from land use, invasive species, and climate change impact aeolian transport. Both simplistic and sophisticated modeling approaches indicate that transport can produce multiple stable states in dryland ecosystems, and thus can participate in large-scale reorganization of soils and vegetation. These results also indicate that manipulation of aeolian transport might provide the opportunity to step some drylands back from critical thresholds and begin the process of recovery from unwanted ecosystem states.

  3. 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.

  4. 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}}}.

  5. Trigonometric potentials arising from the spheroidal equation: Supersymmetric partners and integral formulas

    NASA Astrophysics Data System (ADS)

    Schulze-Halberg, Axel

    2016-06-01

    We construct supersymmetric partners of a quantum system featuring a class of trigonometric potentials that emerge from the spheroidal equation. Examples of both standard and confluent supersymmetric transformations are presented. Furthermore, we use integral formulas arising from the confluent supersymmetric formalism to derive new representations for single and multiple integrals of spheroidal functions.

  6. Higgs-stoponium mixing near the stop-antistop threshold

    NASA Astrophysics Data System (ADS)

    Bodwin, Geoffrey T.; Chung, Hee Sok; Wagner, Carlos E. M.

    2017-01-01

    Supersymmetric extensions of the standard model contain additional heavy neutral Higgs bosons that are coupled to heavy scalar top quarks (stops). This system exhibits interesting field theoretic phenomena when the Higgs mass is close to the stop-antistop production threshold. Existing work in the literature has examined the digluon-to-diphoton cross section near threshold and has focused on enhancements in the cross section that might arise either from the perturbative contributions to the Higgs-to-digluon and Higgs-to-diphoton form factors or from mixing of the Higgs boson with stoponium states. Near threshold, enhancements in the relevant amplitudes that go as inverse powers of the stop-antistop relative velocity require resummations of perturbation theory and/or nonperturbative treatments. We present a complete formulation of threshold effects at leading order in the stop-antistop relative velocity in terms of nonrelativistic effective field theory. We give detailed numerical calculations for the case in which the stop-antistop Green's function is modeled with a Coulomb-Schrödinger Green's function. We find several general effects that do not appear in a purely perturbative treatment. Higgs-stop-antistop mixing effects displace physical masses from the threshold region, thereby rendering the perturbative threshold enhancements inoperative. In the case of large Higgs-stop-antistop couplings, the displacement of a physical state above threshold substantially increases its width, owing to its decay width to a stop-antistop pair, and greatly reduces its contribution to the cross section.

  7. 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

  8. Microinvasive lobular carcinoma arising in a fibroadenoma.

    PubMed

    Hayes, Brian D; Quinn, Cecily M

    2013-08-01

    A 51-year-old woman had a 35 mm circumscribed calcified lesion identified on screening mammography, designated R4. Excision showed a fibroadenoma with multiple foci of lobular neoplasia (atypical lobular hyperplasia and classical lobular carcinoma in situ [LCIS]). A focus of microinvasive lobular carcinoma (MILC) was also present, confirmed on immunohistochemistry. The MILC cells were ER positive, Her-2-negative, and e-cadherin negative. Microinvasive carcinoma, defined as "invasive carcinoma with no focus measuring >1 mm" (TNM UICC 7th edition) is usually encountered in ductal carcinoma in situ but may occur with classical, florid, or pleomorphic LCIS. In one series MILC constituted 0.4% of all invasive lobular carcinomas and was present in 0.4% of all LCIS. MILC is a histologically subtle lesion, the identification of which lends further weight to the concept of lobular neoplasia as a precursor lesion. MILC has been observed in hamartoma but, to our knowledge, has not previously been reported in fibroadenoma.

  9. 32 CFR 536.110 - Notification of incidents arising under international agreements (for claims arising in the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Notification of incidents arising under international agreements (for claims arising in the United States). 536.110 Section 536.110 National Defense... Claims Cognizable Under International Agreements § 536.110 Notification of incidents arising...

  10. Mathematical problems arising in interfacial electrohydrodynamics

    NASA Astrophysics Data System (ADS)

    Tseluiko, Dmitri

    In this work we consider the nonlinear stability of thin films in the presence of electric fields. We study a perfectly conducting thin film flow down an inclined plane in the presence of an electric field which is uniform in its undisturbed state, and normal to the plate at infinity. In addition, the effect of normal electric fields on films lying above, or hanging from, horizontal substrates is considered. Systematic asymptotic expansions are used to derive fully nonlinear long wave model equations for the scaled interface motion and corresponding flow fields. For the case of an inclined plane, higher order terms are need to be retained to regularize the problem in the sense that the long wave approximation remains valid for long times. For the case of a horizontal plane the fully nonlinear evolution equation which is derived at the leading order, is asymptotically correct and no regularization procedure is required. In both physical situations, the effect of the electric field is to introduce a non-local term which arises from the potential region above the liquid film, and enters through the electric Maxwell stresses at the interface. This term is always linearly destabilizing and produces growth rates proportional to the cubic power of the wavenumber - surface tension is included and provides a short wavelength cut-off, that is, all sufficiently short waves are linearly stable. For the case of film flow down an inclined plane, the fully nonlinear equation can produce singular solutions (for certain parameter values) after a finite time, even in the absence of an electric field. This difficulty is avoided at smaller amplitudes where the weakly nonlinear evolution is governed by an extension of the Kuramoto-Sivashinsky (KS) equation. Global existence and uniqueness results are proved, and refined estimates of the radius of the absorbing ball in L2 are obtained in terms of the parameters of the equations for a generalized class of modified KS equations. The

  11. The absolute threshold of cone vision

    PubMed Central

    Koeing, Darran; Hofer, Heidi

    2013-01-01

    We report measurements of the absolute threshold of cone vision, which has been previously underestimated due to sub-optimal conditions or overly strict subjective response criteria. We avoided these limitations by using optimized stimuli and experimental conditions while having subjects respond within a rating scale framework. Small (1′ fwhm), brief (34 msec), monochromatic (550 nm) stimuli were foveally presented at multiple intensities in dark-adapted retina for 5 subjects. For comparison, 4 subjects underwent similar testing with rod-optimized stimuli. Cone absolute threshold, that is, the minimum light energy for which subjects were just able to detect a visual stimulus with any response criterion, was 203 ± 38 photons at the cornea, ∼0.47 log units lower than previously reported. Two-alternative forced-choice measurements in a subset of subjects yielded consistent results. Cone thresholds were less responsive to criterion changes than rod thresholds, suggesting a limit to the stimulus information recoverable from the cone mosaic in addition to the limit imposed by Poisson noise. Results were consistent with expectations for detection in the face of stimulus uncertainty. We discuss implications of these findings for modeling the first stages of human cone vision and interpreting psychophysical data acquired with adaptive optics at the spatial scale of the receptor mosaic. PMID:21270115

  12. $1+ Cotton? New Thresholds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton is a major crop in Arizona and is affected by multiple insect pests. A highly effective and economically efficient integrated pest management program has been developed for the major pests of cotton. The program utilizes sampling to determine the abundance of pest insects in the field and eco...

  13. Black hole mass threshold from nonsingular quantum gravitational collapse.

    PubMed

    Bojowald, Martin; Goswami, Rituparno; Maartens, Roy; Singh, Parampreet

    2005-08-26

    Quantum gravity is expected to remove the classical singularity that arises as the end state of gravitational collapse. To investigate this, we work with a toy model of a collapsing homogeneous scalar field. We show that nonperturbative semiclassical effects of loop quantum gravity cause a bounce and remove the black hole singularity. Furthermore, we find a critical threshold scale below which no horizon forms: quantum gravity may exclude very small astrophysical black holes.

  14. 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.

  15. 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.

  16. Identifying Thresholds for Ecosystem-Based Management

    PubMed Central

    Samhouri, Jameal F.; Levin, Phillip S.; Ainsworth, Cameron H.

    2010-01-01

    Background One of the greatest obstacles to moving ecosystem-based management (EBM) from concept to practice is the lack of a systematic approach to defining ecosystem-level decision criteria, or reference points that trigger management action. Methodology/Principal Findings To assist resource managers and policymakers in developing EBM decision criteria, we introduce a quantitative, transferable method for identifying utility thresholds. A utility threshold is the level of human-induced pressure (e.g., pollution) at which small changes produce substantial improvements toward the EBM goal of protecting an ecosystem's structural (e.g., diversity) and functional (e.g., resilience) attributes. The analytical approach is based on the detection of nonlinearities in relationships between ecosystem attributes and pressures. We illustrate the method with a hypothetical case study of (1) fishing and (2) nearshore habitat pressure using an empirically-validated marine ecosystem model for British Columbia, Canada, and derive numerical threshold values in terms of the density of two empirically-tractable indicator groups, sablefish and jellyfish. We also describe how to incorporate uncertainty into the estimation of utility thresholds and highlight their value in the context of understanding EBM trade-offs. Conclusions/Significance For any policy scenario, an understanding of utility thresholds provides insight into the amount and type of management intervention required to make significant progress toward improved ecosystem structure and function. The approach outlined in this paper can be applied in the context of single or multiple human-induced pressures, to any marine, freshwater, or terrestrial ecosystem, and should facilitate more effective management. PMID:20126647

  17. Cost–effectiveness thresholds: pros and cons

    PubMed Central

    Lauer, Jeremy A; De Joncheere, Kees; Edejer, Tessa; Hutubessy, Raymond; Kieny, Marie-Paule; Hill, Suzanne R

    2016-01-01

    Abstract Cost–effectiveness analysis is used to compare the costs and outcomes of alternative policy options. Each resulting cost–effectiveness ratio represents the magnitude of additional health gained per additional unit of resources spent. Cost–effectiveness thresholds allow cost–effectiveness ratios that represent good or very good value for money to be identified. In 2001, the World Health Organization’s Commission on Macroeconomics in Health suggested cost–effectiveness thresholds based on multiples of a country’s per-capita gross domestic product (GDP). In some contexts, in choosing which health interventions to fund and which not to fund, these thresholds have been used as decision rules. However, experience with the use of such GDP-based thresholds in decision-making processes at country level shows them to lack country specificity and this – in addition to uncertainty in the modelled cost–effectiveness ratios – can lead to the wrong decision on how to spend health-care resources. Cost–effectiveness information should be used alongside other considerations – e.g. budget impact and feasibility considerations – in a transparent decision-making process, rather than in isolation based on a single threshold value. Although cost–effectiveness ratios are undoubtedly informative in assessing value for money, countries should be encouraged to develop a context-specific process for decision-making that is supported by legislation, has stakeholder buy-in, for example the involvement of civil society organizations and patient groups, and is transparent, consistent and fair. PMID:27994285

  18. Ventricular fibrillation threshold of rapid short pulses.

    PubMed

    Walcott, Gregory P; Kroll, Mark W; Ideker, Raymond E

    2011-01-01

    The risk of VF (ventricular fibrillation) from continuous AC utility (50/60 Hz) power has been well quantified and is reflected in accepted standards. Similarly, the required charge for a single pulse delivered during the T-wave of the ECG is also quantified. However, there are no studies that deal with the VF risk of a train of multiple short pulses such as those used in electric fences and conducted electrical weapons (CEWs). We studied 5 swine with an electrode placed through the anterior chest such that the tip was 10 mm from the epicardium. A return electrode was attached remotely to the lower abdomen. Five-second trains of 100 μs pulses at rates of 10-70 PPS (pulses per second) were delivered with gradually increasing charges until VF was induced. The VF threshold was also determined for 60 Hz AC current. As expected, the VF charge threshold decreased with increasing rates. For pulse rates between 10-30 PPS, the aggregate current (= charge • pulse rate) was constant at the VF threshold. The VF threshold in terms of AC RMS current was 7.4 ± 1.9 times the aggregate current VF threshold for the rapid short pulses. These results may have utility for setting safety standards for electric fences and for CEWs such as TASER® CEWs. This also allows for the risk assessment of CEWs by comparison to international electrical safety standards. The output of these weapons appears to be well below the VF risk limits as set by these standards.

  19. 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.

  20. Interevent Correlations from Avalanches Hiding Below the Detection Threshold.

    PubMed

    Janićević, Sanja; Laurson, Lasse; Måløy, Knut Jørgen; Santucci, Stéphane; Alava, Mikko J

    2016-12-02

    Numerous systems ranging from deformation of materials to earthquakes exhibit bursty dynamics, which consist of a sequence of events with a broad event size distribution. Very often these events are observed to be temporally correlated or clustered, evidenced by power-law-distributed waiting times separating two consecutive activity bursts. We show how such interevent correlations arise simply because of a finite detection threshold, created by the limited sensitivity of the measurement apparatus, or used to subtract background activity or noise from the activity signal. Data from crack-propagation experiments and numerical simulations of a nonequilibrium crack-line model demonstrate how thresholding leads to correlated bursts of activity by separating the avalanche events into subavalanches. The resulting temporal subavalanche correlations are well described by our general scaling description of thresholding-induced correlations in crackling noise.

  1. Interevent Correlations from Avalanches Hiding Below the Detection Threshold

    NASA Astrophysics Data System (ADS)

    Janićević, Sanja; Laurson, Lasse; Mâløy, Knut Jørgen; Santucci, Stéphane; Alava, Mikko J.

    2016-12-01

    Numerous systems ranging from deformation of materials to earthquakes exhibit bursty dynamics, which consist of a sequence of events with a broad event size distribution. Very often these events are observed to be temporally correlated or clustered, evidenced by power-law-distributed waiting times separating two consecutive activity bursts. We show how such interevent correlations arise simply because of a finite detection threshold, created by the limited sensitivity of the measurement apparatus, or used to subtract background activity or noise from the activity signal. Data from crack-propagation experiments and numerical simulations of a nonequilibrium crack-line model demonstrate how thresholding leads to correlated bursts of activity by separating the avalanche events into subavalanches. The resulting temporal subavalanche correlations are well described by our general scaling description of thresholding-induced correlations in crackling noise.

  2. Dose-response thresholds for progressive diseases.

    PubMed

    Cox, Louis Anthony Tony

    2012-01-01

    Many diseases, including cancers, heart diseases, and lung diseases, can usefully be viewed as arising from disruption of feedback control systems that normally maintain homeostasis of tissues and cell populations. Excessive exposure can destabilize feedback control loops, leading to sustained elevation of variables to saturated levels and clinical consequences such as chronic unresolved inflammation, destruction of tissue (as in emphysema), proliferation of cell populations (as in lung cancer), and increases in reactive oxygen species and protease levels (as in coronary heart diseases and chronic obstructive lung disease). We propose a framework for understanding how exposure can destabilize normally homeostatic feedback control systems and create sustained imbalances and elevated levels of disease-related variables, by creating a new, locally stable, alternative equilibrium for the dynamic system, in addition to its normal (homeostatic) equilibrium. The resulting model, which we call alternative-equilibria (AE) theory, implies the existence of an exposure threshold below which transition to the alternative equilibrium (potential disease) state will not occur. Once this threshold is exceeded, progression to the alternative equilibrium continues spontaneously, even without further exposure. These predictions may help to explain patterns observed in experimental and epidemiological data for diseases such as COPD, silicosis, and inflammation-mediated lung cancer.

  3. 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…

  4. 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.…

  5. Spitz nevus arising upon a congenital glomuvenous malformation.

    PubMed

    Arica, Deniz A; Arica, Ibrahim E; Yayli, Savas; Cobanoglu, Umit; Akay, Bengu N; Anadolu, Rana; Bahadir, Sevgi

    2013-01-01

    There are several reports of the collision of vascular and pigmentary anomalies (e.g., phakomatosis pigmentovascularis) and the association between congenital melanocytic nevi and infantile hemangiomas. We report a case of Spitz nevus arising in skin overlying a congenital plaque-like glomuvenous malformation (GVM). This is the first report of a Spitz nevus arising in direct contiguity to a GVM.

  6. 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...

  7. 12 CFR 221.110 - Questions arising under this part.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 12 Banks and Banking 3 2010-01-01 2010-01-01 false Questions arising under this part. 221.110 Section 221.110 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF GOVERNORS OF THE FEDERAL... CARRYING MARGIN STOCK (REGULATION U) Interpretations § 221.110 Questions arising under this part. (a)...

  8. Learning regulatory programs by threshold SVD regression.

    PubMed

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

    2014-11-04

    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.

  9. 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.

  10. 32 CFR 536.111 - Investigation of claims arising under international agreements (for those claims arising in the...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 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...

  11. Tenosynovial Giant Cell Tumor Arising on the Scapular Region

    PubMed Central

    Fukuda, Asako; Ueno, Takashi; Takayama, Ryoko; Ansai, Shin-ichi; Futagami, Ayako; Kawana, Seiji

    2013-01-01

    Tenosynovial giant cell tumor (TSGCT) is a benign soft tissue tumor arising from the synovial membrane that composes the lining of joints, tendons and bursae. TSGCT is a common tumor occurring in the hands and fingers, and also consecutively in the knees, ankles, feet and hips. It is rarely found in the scapular region. To the best of our knowledge, only 2 cases arising on the upper back have been reported. This report presents the case of a 44-year-old Japanese female with a TSGCT arising on her right scapular region. PMID:24403889

  12. 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.

  13. Threshold photodissociation of Cr+2

    NASA Astrophysics Data System (ADS)

    Lessen, D. E.; Asher, R. L.; Brucat, P. J.

    1991-08-01

    A one-photon photodissociation threshold for supersonically cooled Cr+2 is determined to be 2.13 eV. This threshold provides a strict upper limit to the adiabatic binding energy of the ground state of chromium dimer cation if the initial internal energy of the parent ion may be neglected. From the difference in the IPs of chromium atom and dimer, an upper limit to the dissociation of Cr2 is placed at 1.77 eV.

  14. 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.

  15. Chemical complexity of odors increases reliability of olfactory threshold testing.

    PubMed

    Oleszkiewicz, Anna; Pellegrino, Robert; Pusch, Katharina; Margot, Celine; Hummel, Thomas

    2017-01-10

    Assessment of odor thresholds is a widely recognized method of measuring olfactory abilities in humans. To date no attempts have been made to assess whether chemical complexity of odors used can produce more reliable results. To this end, we performed two studies of repeated measures design with 121 healthy volunteers (age 19-62 years). In Study 1, we compared thresholds obtained from tests based on one odor presented in a pen-like odor dispensing device with three odors and six odors mixtures presented in glass containers. In study 2 we compared stimuli of one and three odors, both presented in glass containers. In both studies measurements were performed twice, separated by at least three days. Results indicate that the multiple odor mixtures produced more reliable threshold scores, as compared to thresholds based on a single substance.

  16. Chemical complexity of odors increases reliability of olfactory threshold testing

    PubMed Central

    Oleszkiewicz, Anna; Pellegrino, Robert; Pusch, Katharina; Margot, Celine; Hummel, Thomas

    2017-01-01

    Assessment of odor thresholds is a widely recognized method of measuring olfactory abilities in humans. To date no attempts have been made to assess whether chemical complexity of odors used can produce more reliable results. To this end, we performed two studies of repeated measures design with 121 healthy volunteers (age 19–62 years). In Study 1, we compared thresholds obtained from tests based on one odor presented in a pen-like odor dispensing device with three odors and six odors mixtures presented in glass containers. In study 2 we compared stimuli of one and three odors, both presented in glass containers. In both studies measurements were performed twice, separated by at least three days. Results indicate that the multiple odor mixtures produced more reliable threshold scores, as compared to thresholds based on a single substance. PMID:28071665

  17. [Threshold mechanism of the control of cascade proteolysis].

    PubMed

    Shcherbak, I G

    1998-05-01

    The immune lysis rate of erythrocytes vs. the concentration of particular complement components was studied. It was found that in the presence of component C1 (but not C3) and factors B and D, the cells undergo lysis after the concentration of these compounds exceeds a "threshold" value. The threshold molar concentrations of factors D and B exceeded 5- and 20-fold, respectively, that of component C1. The multiplicity and different capacities of the thresholds allow the fragmentary activation of cascade proteolysis at stretches between neighboring thresholds without the total realization of the final effect of the system (cell lysis, clot formation, etc.). The resulting peptideby-products (bypass peptides) may possess their own biological activity. It is the generation of various bioregulators that appears to be the main function of the cascade proteolytic systems functioning in the subthreshold regime.

  18. Resonant effects in above-threshold ionization

    NASA Astrophysics Data System (ADS)

    Hertlein, Marcus P.

    2000-09-01

    The ionization of noble gases in high intensity laser fields produces an electron spectrum with characteristic peaks corresponding to atomic levels of the atom. While many of the features in the low energy part of the spectrum have been explained qualitatively, current models are incomplete and are not able to account for the recurrence of ionization probability for higher energy electrons. In particular, one of the basic questions arising is the importance of multiple ionization in these spectra. While the light intensities are in the regime where multiple ionization is known to occur, it was not clear whether the higher energy (or plateau) electrons are a result of this, and whether multiple ionization even leaves a signature in the electron spectrum. In this dissertation, we use several experimental techniques to explore this problem in argon. Our results show that although multiple ionization occurs, electrons from this process do not appear in the observed electron spectrum. Furthermore, the appearance intensities of the peaks visible in the plateau region of the electron spectrum and of the resonance peaks in the well- understood low energy part show a strong correlation, suggestion a common origin of production. Accurate computer simulations of the process, using a single- active-electron model, reproduce all essential features of the experimental spectra. Our results support the conclusion that all high energy electrons observed in our experiments can be explained with single-electron effects.

  19. Prewhitening of Colored Noise Fields for Detection of Threshold Sources

    DTIC Science & Technology

    1993-11-07

    determines the noise covariance matrix, prewhitening techniques allow detection of threshold sources. The multiple signal classification ( MUSIC ...SUBJECT TERMS 1S. NUMBER OF PAGES AR Model, Colored Noise Field, Mixed Spectra Model, MUSIC , Noise Field, 52 Prewhitening, SNR, Standardized Test...EXAMPLE 2: COMPLEX AR COEFFICIENT .............................................. 5 EXAMPLE 3: MUSIC IN A COLORED BACKGROUND NOISE ...................... 6

  20. 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

    2015-07-03

    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

  1. On computational Gestalt detection thresholds.

    PubMed

    Grompone von Gioi, Rafael; Jakubowicz, Jérémie

    2009-01-01

    The aim of this paper is to show some recent developments of computational Gestalt theory, as pioneered by Desolneux, Moisan and Morel. The new results allow to predict much more accurately the detection thresholds. This step is unavoidable if one wants to analyze visual detection thresholds in the light of computational Gestalt theory. The paper first recalls the main elements of computational Gestalt theory. It points out a precision issue in this theory, essentially due to the use of discrete probability distributions. It then proposes to overcome this issue by using continuous probability distributions and illustrates it on the meaningful alignment detector of Desolneux et al.

  2. Low Threshold Quantum Dot Lasers.

    PubMed

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

    2016-04-07

    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.

  3. Bulk optical damage thresholds for doped and undoped, crystalline and ceramic yttrium aluminum garnet.

    PubMed

    Do, Binh T; Smith, Arlee V

    2009-06-20

    We measured the bulk optical damage thresholds of pure and Nd-doped ceramic yttrium aluminum garnet (YAG), and of pure, Nd-doped, Cr-doped, and Yb-doped crystalline YAG. We used 9.9 ns, 1064 nm, single-longitudinal mode, TEM00 pulses, to determine that the breakdown thresholds are deterministic, with multiple-pulse thresholds ranging from 1.1 to 2.2 kJ/cm2.

  4. 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

  5. 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…

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

    PubMed Central

    Birtwistle, Marc R.

    2015-01-01

    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 310 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 107 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

  7. 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.

  8. 77 FR 59618 - Medicare Program; Medicare Appeals; Adjustment to the Amount in Controversy Threshold Amounts for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-28

    ... to the Amount in Controversy Threshold Amounts for Calendar Year 2013 AGENCY: Centers for Medicare... for requests for ALJ hearings and judicial review filed on or after January 1, 2013. The calendar year... nearest multiple of $10. B. Calendar Year 2013 The AIC threshold amount for ALJ hearing requests...

  9. 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…

  10. 5 CFR 359.404 - Removal: Conditions arising before appointment.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... of Career Appointees During Probation § 359.404 Removal: Conditions arising before appointment. (a) Coverage. (1) This section covers the removal of a career appointee from the SES during the probationary...) This section does not apply, however, when the career appointee was covered under 5 U.S.C....

  11. 5 CFR 359.404 - Removal: Conditions arising before appointment.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... of Career Appointees During Probation § 359.404 Removal: Conditions arising before appointment. (a) Coverage. (1) This section covers the removal of a career appointee from the SES during the probationary...) This section does not apply, however, when the career appointee was covered under 5 U.S.C....

  12. 5 CFR 359.404 - Removal: Conditions arising before appointment.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... of Career Appointees During Probation § 359.404 Removal: Conditions arising before appointment. (a) Coverage. (1) This section covers the removal of a career appointee from the SES during the probationary...) This section does not apply, however, when the career appointee was covered under 5 U.S.C....

  13. 5 CFR 359.404 - Removal: Conditions arising before appointment.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... of Career Appointees During Probation § 359.404 Removal: Conditions arising before appointment. (a) Coverage. (1) This section covers the removal of a career appointee from the SES during the probationary...) This section does not apply, however, when the career appointee was covered under 5 U.S.C....

  14. 5 CFR 359.404 - Removal: Conditions arising before appointment.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... of Career Appointees During Probation § 359.404 Removal: Conditions arising before appointment. (a) Coverage. (1) This section covers the removal of a career appointee from the SES during the probationary...) This section does not apply, however, when the career appointee was covered under 5 U.S.C....

  15. ISODATA: Thresholds for splitting clusters

    NASA Technical Reports Server (NTRS)

    Kan, E. P. F. (Principal Investigator)

    1972-01-01

    The author has identified the following significant results. The parameter AD (average distance) as used in the ISODATA program was critically examined. Thresholds of AD to decide on the splitting of clusters were obtained. For the univariate case, 0.84 was established as a sound choice, after examining several simple, as well as composite, distributions and also after investigating the probability of misclassification when points have to be reassigned to the newly identified clusters. For the multivariate case, the empirical threshold (N-0.16)/square root of N was extrapolated. A final criticism on AD was that AD would lose its effectiveness as a discriminative measure for the present purpose when N was large.

  16. Scaling behavior of threshold epidemics

    NASA Astrophysics Data System (ADS)

    Ben-Naim, E.; Krapivsky, P. L.

    2012-05-01

    We study the classic Susceptible-Infected-Recovered (SIR) model for the spread of an infectious disease. In this stochastic process, there are two competing mechanism: infection and recovery. Susceptible individuals may contract the disease from infected individuals, while infected ones recover from the disease at a constant rate and are never infected again. Our focus is the behavior at the epidemic threshold where the rates of the infection and recovery processes balance. In the infinite population limit, we establish analytically scaling rules for the time-dependent distribution functions that characterize the sizes of the infected and the recovered sub-populations. Using heuristic arguments, we also obtain scaling laws for the size and duration of the epidemic outbreaks as a function of the total population. We perform numerical simulations to verify the scaling predictions and discuss the consequences of these scaling laws for near-threshold epidemic outbreaks.

  17. 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

  18. 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).

  19. New near-threshold mesons

    NASA Astrophysics Data System (ADS)

    Cohen, Thomas D.; Gelman, Boris A.; Nussinov, Shmuel

    2004-01-01

    We show that under a number of rather plausible assumptions QCD spectrum may contain a number of mesons which have not been predicted or observed. Such states will have the quantum numbers of two existing mesons and masses very close to the dissociation threshold into the two mesons. Moreover, at least one of the two mesonic constituents itself must be very close to its dissociation threshold. In particular, one might expect the existence of loosely bound systems of D and D∗sJ(2317); similarly, K and f0(980), K¯ and f0(980), K and a0(980) and K¯ and a0(980) can be bound. The mechanism for binding in these cases is the S-wave kaon exchange. The nearness of one of the constituents to its decay threshold into a kaon plus a remainder, implies that the range of the kaon exchange force becomes abnormally long—significantly longer than 1/mK which greatly aids the binding.

  20. [A case of carcinoma arising in a diverticulum of the transverse colon].

    PubMed

    Nomi, Masako; Umemoto, Satoshi; Kikutake, Takashi; Hosaka, Seiji; Mase, Takahiro; Kawamoto, Shunji; Yoshida, Takahisa

    2014-11-01

    A 64 year-old woman presented with advanced, transverse colon cancer arising in the diverticulum. Tumor invasion extended beyond the serosa to the anal side of the colon. Anemia and fatigue progressed after 6 months of iron administration. The hemoglobin value was 5.3 g/dL and carcinoembryonic antigen (CEA) level was elevated to 44.2 ng/mL. A palpable and tender fist-sized mass was found in the right upper abdomen. Computed tomography (CT) revealed a low-density mass in the transverse colon invading beyond the serosa to the anal side of the colon. Right hemi-colectomy with lymph node dissection was performed. The resected specimen contained multiple diverticula including the one from which the tumor arose. Histological examination revealed a well-differentiated, tubular adenocarcinoma (UICC TNM T4bN0M0) arising in a transverse colon diverticulum. There has been no recurrence for 2 years. Colon cancer arising in a diverticulum may expand to the extra-serosa and easily invade to the adjacent organ. In such cases, malignancy should be considered.

  1. 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.

  2. Bedding material affects mechanical thresholds, heat thresholds and texture preference

    PubMed Central

    Moehring, Francie; O’Hara, Crystal L.; Stucky, Cheryl L.

    2015-01-01

    It has long been known that the bedding type animals are housed on can affect breeding behavior and cage environment. Yet little is known about its effects on evoked behavior responses or non-reflexive behaviors. C57BL/6 mice were housed for two weeks on one of five bedding types: Aspen Sani Chips® (standard bedding for our institute), ALPHA-Dri®, Cellu-Dri™, Pure-o’Cel™ or TEK-Fresh. Mice housed on Aspen exhibited the lowest (most sensitive) mechanical thresholds while those on TEK-Fresh exhibited 3-fold higher thresholds. While bedding type had no effect on responses to punctate or dynamic light touch stimuli, TEK-Fresh housed animals exhibited greater responsiveness in a noxious needle assay, than those housed on the other bedding types. Heat sensitivity was also affected by bedding as animals housed on Aspen exhibited the shortest (most sensitive) latencies to withdrawal whereas those housed on TEK-Fresh had the longest (least sensitive) latencies to response. Slight differences between bedding types were also seen in a moderate cold temperature preference assay. A modified tactile conditioned place preference chamber assay revealed that animals preferred TEK-Fresh to Aspen bedding. Bedding type had no effect in a non-reflexive wheel running assay. In both acute (two day) and chronic (5 week) inflammation induced by injection of Complete Freund’s Adjuvant in the hindpaw, mechanical thresholds were reduced in all groups regardless of bedding type, but TEK-Fresh and Pure-o’Cel™ groups exhibited a greater dynamic range between controls and inflamed cohorts than Aspen housed mice. PMID:26456764

  3. Analysis of the vibratory excitation arising from spiral bevel gears

    NASA Technical Reports Server (NTRS)

    Mark, William D.

    1987-01-01

    Tools required to understand and predict in terms of its underlying causes the vibratory excitation arising from meshing spiral bevel gears are developed. A generalized three component transmission error of meshing spiral bevel gears is defined. Equations are derived that yield the three components of the generalized transmission error in terms of deviations of tooth running surfaces from equispaced perfect spherical involute surfaces and tooth/gearbody elastic deformations arising from the three components of the generalized force transmitted by the meshing gears. A method for incorporating these equations into the equations of motion of a gear system is described. Equations are derived for the three components of the generalized force transmitted by the gears which are valid whenever inertial effects of the meshing gears and their supports are negligible. Bearing offsets from the positions occupied by the shaft centerlines of perfect spherical involute bevel gears and bearing/bearing support flexibilities enter into the computation of these forces.

  4. 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.

  5. A Primary Ossifying Intracranial Myxoma Arising from the Ethmoid Sinus

    PubMed Central

    Ryu, Je Il; Kim, Jae Min; Kim, Choong Hyun

    2015-01-01

    Myxomas are rare benign tumors that originate from mesenchymal tissue. They usually develop in the atrium of the heart, the skin, subcutaneous tissue, or bone. Involvement of the skull base with an intracranial extension is very rare and not well-described in the literature. We report a rare case of primary intracranial ossifying myxoma arising from the anterior skull base and mimicking a huge chondrosarcoma, and we review the relevant literature. PMID:26539274

  6. Apocrine carcinoma arising in a complex fibroadenoma: a case report.

    PubMed

    Mele, Marco; Vahl, Pernille; Funder, Jonas Amstrup; Sorensen, Anne Schmidt; Jensen, Vibeke

    2014-01-01

    A carcinoma arising in a fibroadenoma is a rare event, which often entails a diagnostic challenge. The most common type is the lobular carcinoma and secondary a ductal carcinoma. We present an extremely rare case of malignant development of an invasive apocrine carcinoma in a complex fibroadenoma and underline the importance for clinicians to recognize the possibility of benign and malignant co-existence especially in older women.

  7. Detecting Departure From Additivity Along a Fixed-Ratio Mixture Ray With a Piecewise Model for Dose and Interaction Thresholds

    PubMed Central

    Gennings, Chris; Wagner, Elizabeth D.; Simmons, Jane Ellen; Plewa, Michael J.

    2010-01-01

    For mixtures of many chemicals, a ray design based on a relevant, fixed mixing ratio is useful for detecting departure from additivity. Methods for detecting departure involve modeling the response as a function of total dose along the ray. For mixtures with many components, the interaction may be dose dependent. Therefore, we have developed the use of a three-segment model containing both a dose threshold and an interaction threshold. Prior to the dose threshold, the response is that of background; between the dose threshold and the interaction threshold, an additive relationship exists; the model allows for departure from additivity beyond the interaction threshold. With such a model, we can conduct a hypothesis test of additivity, as well as a test for a region of additivity. The methods are illustrated with cytotoxicity data that arise when Chinese hamster ovary cells are exposed to a mixture of nine haloacetic acids. PMID:21359103

  8. Distinguishing Indirect Signatures Arising From New Physics at the NLC

    SciTech Connect

    Rizzo, Thomas G.

    1999-07-14

    Many sources of new physics can lead to shifts in the Standard Model predictions for cross sections and asymmetries at the NLC below their direct production thresholds. In this talk we discuss some of the tools that are useful for distinguishing amongst these new physics scenarios. R-parity violation and extensions of the Standard Model gauge structure are two typical non-minimal realizations of supersymmetry which provide us with an important test case to examine.

  9. Strong-field above-threshold ionization in laser-irradiated C60: The signatures of orbital symmetry and intramolecular interference

    NASA Astrophysics Data System (ADS)

    Usachenko, Vladimir; Kim, Vyacheslav; Pyak, Pavel

    2015-05-01

    We report about the results of our theoretical study of strong-field (multiphoton) above-threshold ionization (ATI) in laser-irradiated carbon fullerene molecule C60 under condition of relevant experiment. The problem is addressed within the velocity-gauge (VG) formulation of molecular strong-field approximation (SFA) essentially exploiting the density-functional-theory (DFT) method for numerical composition of initial (laser-free) molecular state using the routines of GAUSSIAN-03 code. The results of our present VG-SFA calculation for C60 photoelectron energy spectra (PES) demonstrate two distinct (well-separated) and pronounced local interference minima - in the low-energy and the high-energy domains of produced PES - both arising due to destructive intramolecular (multislit) quantum interference of strong-field ionization corresponding to photoelectron emission from multiple separate atomic centers.

  10. Squamous cell carcinoma arising in previously burned or irradiated skin

    SciTech Connect

    Edwards, M.J.; Hirsch, R.M.; Broadwater, J.R.; Netscher, D.T.; Ames, F.C.

    1989-01-01

    Squamous cell carcinoma (SCC) arising in previously burned or irradiated skin was reviewed in 66 patients treated between 1944 and 1986. Healing of the initial injury was complicated in 70% of patients. Mean interval from initial injury to diagnosis of SCC was 37 years. The overwhelming majority of patients presented with a chronic intractable ulcer in previously injured skin. The regional relapse rate after surgical excision was very high, 58% of all patients. Predominant patterns of recurrence were in local skin and regional lymph nodes (93% of recurrences). Survival rates at 5, 10, and 20 years were 52%, 34%, and 23%, respectively. Five-year survival rates in previously burned and irradiated patients were not significantly different (53% and 50%, respectively). This review, one of the largest reported series, better defines SCC arising in previously burned or irradiated skin as a locally aggressive disease that is distinct from SCC arising in sunlight-damaged skin. An increased awareness of the significance of chronic ulceration in scar tissue may allow earlier diagnosis. Regional disease control and survival depend on surgical resection of all known disease and may require radical lymph node dissection or amputation.

  11. 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.

  12. 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.

  13. 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.

  14. Androstadienone odor thresholds in adolescents.

    PubMed

    Hummel, Thomas; Krone, Franziska; Lundström, Johan N; Bartsch, Oliver

    2005-03-01

    A sex-related difference in olfactory sensitivity to androstenone has been reported to occur during adolescence. More males than females exhibited anosmia to androstenone, or an increase in androstenone threshold with age. The current study addressed the question whether similar, sexually dimorphic effects of aging over puberty can also be found for androstadienone. A total of 102 subjects participated (36 females, 66 males). Similar to previous investigations, subjects were divided into a group of 47 individuals with a mean age of 13.3 years, defined as pre/peri-pubertal, and a group of 55 subjects with a mean age of 17.1 years, defined as post-pubertal. All subjects underwent tests for verbal abilities, general olfactory function, and measurements of androstadienone thresholds. The study provided the following major results: (1) Male subjects exhibited higher androstadienone sensitivity in the pre/peri-pubertal group as compared to the post-pubertal group. This difference was not observed in female subjects. Correspondingly, a negative correlation between age and androstadienone sensitivity was found for male subjects, but not for female subjects. (2) In contrast to this sex-specific change of the androstadienone odor threshold, verbal skills and odor identification abilities increased with age in all subjects regardless of their sex. In conclusion, the present observations confirm previous research on sex-differentiated effects of aging during puberty on sensitivity towards odorous steroids. While the underlying causes are unknown, it may be hypothesized that the decreased sensitivity could result from the increased endogenous levels of androstadienone in male subjects. Future studies should include both steroid and non-steroid odorants to further explore these age-related changes.

  15. 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

  16. The increase of the spin-transfer torque threshold current density in coupled vortex domain walls.

    PubMed

    Lepadatu, S; Mihai, A P; Claydon, J S; Maccherozzi, F; Dhesi, S S; Kinane, C J; Langridge, S; Marrows, C H

    2012-01-18

    We have studied the dependence on the domain wall structure of the spin-transfer torque current density threshold for the onset of wall motion in curved, Gd-doped Ni(80)Fe(20) nanowires with no artificial pinning potentials. For single vortex domain walls, for both 10% and 1% Gd-doping concentrations, the threshold current density is inversely proportional to the wire width and significantly lower compared to the threshold current density measured for transverse domain walls. On the other hand for high Gd concentrations and large wire widths, double vortex domain walls are formed which require an increase in the threshold current density compared to single vortex domain walls at the same wire width. We suggest that this is due to the coupling of the vortex cores, which are of opposite chirality, and hence will be acted on by opposing forces arising through the spin-transfer torque effect.

  17. The appropriate threshold for declaring linkage when allowing sex-specific recombination rates.

    PubMed Central

    Lander, E S; Lincoln, S E

    1988-01-01

    In human genetics, two loci are declared to be linked when the lod score at the maximum likelihood recombination fraction theta exceeds the threshold of 3.0. Since recombination rates differ between the sexes, one can alternatively detect linkage by estimating separate recombination rates, theta m and theta f, for male and female meiosis and examining the corresponding sex-specific lod scores. The question arises: In order to maintain the same chance of falsely declaring linkage, what is the correct threshold for declaring linkage when sex-specific lod scores are used? We show here that the appropriate threshold is about 3.5. If the restriction that theta f greater than theta m is added, the appropriate threshold falls to about 3.25. We also discuss the relative efficiency of detecting linkage by using sex-specific and sex-averaged lod scores. PMID:3177382

  18. Ultra-low threshold polariton condensation

    NASA Astrophysics Data System (ADS)

    Steger, Mark; Fluegel, Brian; Alberi, Kirstin; Snoke, David W.; Pfeiffer, Loren N.; West, Ken; Mascarenhas, Angelo

    2017-03-01

    We demonstrate condensation of microcavity polaritons with a very sharp threshold occuring at two orders of magnitude lower pump intensity than previous demonstrations of condensation. The long cavity-lifetime and trapping and pumping geometries are crucial to the realization of this low threshold. Polariton condensation, or "polariton lasing" has long been proposed as a promising source of coherent light at lower threshold than traditional lasing, and these results suggest methods to bring this threshold even lower.

  19. Ultra-low threshold polariton condensation.

    PubMed

    Steger, Mark; Fluegel, Brian; Alberi, Kirstin; Snoke, David W; Pfeiffer, Loren N; West, Ken; Mascarenhas, Angelo

    2017-03-15

    We demonstrate the condensation of microcavity polaritons with a very sharp threshold occurring at a two orders of magnitude pump intensity lower than previous demonstrations of condensation. The long cavity lifetime and trapping and pumping geometries are crucial to the realization of this low threshold. Polariton condensation, or "polariton lasing" has long been proposed as a promising source of coherent light at a lower threshold than traditional lasing, and these results indicate some considerations for optimizing designs for lower thresholds.

  20. Critical nonlinear phenomena for kinetic instabilities near threshold

    SciTech Connect

    Breizman, B.N.; Berk, H.L.; Pekker, M.S.; Porcelli, F.; Stupakov, G.V.; Wong, K.L.

    1997-05-01

    A universal integral equation has been derived and solved for the nonlinear evolution of collective modes driven by kinetic wave particle resonances just above the threshold for instability. The dominant nonlinearity stems from the dynamics of resonant particles that can be treated perturbatively near the marginal state of the system. With a resonant particle source and classical relaxation processes included, the new equation allows the determination of conditions for a soft nonlinear regime, where the saturation level is proportional to the increment above threshold, or a hard nonlinear regime, characterized by explosive behavior, where the saturation level is independent of the closeness to threshold. In the hard regime, rapid oscillations typically arise that lead to large frequency shifts in a fully developed nonlinear stage. The universality of the approach suggests that the theory applies to many types of resonant particle driven instabilities, and several specific cases, viz. energetic particle driven Alfv{acute e}n wave excitation, the fishbone oscillation, and a collective mode in particle accelerators, are discussed. {copyright} {ital 1997 American Institute of Physics.}

  1. 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.

  2. 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…

  3. Iterative wavelet thresholding for rapid MRI reconstruction

    NASA Astrophysics Data System (ADS)

    Kayvanrad, Mohammad H.; McKenzie, Charles A.; Peters, Terry M.

    2011-03-01

    According to the developments in the field of compressed sampling and and sparse recovery, one might take advantage of the sparsity of an object, as an additional a priori knowledge about the object, to reconstruct it from fewer samples than that needed by the traditional sampling strategies. Since most magnetic resonance (MR) images are sparse in some domain, in this work we consider the problem of MR reconstruction and how one could apply this idea to accelerate the process of MR image/map acquisition. In particular, based on the Paupolis-Gerchgerg algorithm, an iterative thresholding algorithm for reconstruction of MR images from limited k-space observations is proposed. The proposed method takes advantage of the sparsity of most MR images in the wavelet domain. Initializing with a minimum-energy reconstruction, the object of interest is reconstructed by going through a sequence of thresholding and recovery iterations. Furthermore, MR studies often involve acquisition of multiple images in time that are highly correlated. This correlation can be used as additional knowledge on the object beside the sparsity to further reduce the reconstruction time. The performance of the proposed algorithms is experimentally evaluated and compared to other state-of-the-art methods. In particular, we show that the quality of reconstruction is increased compared to total variation (TV) regularization, and the conventional Papoulis-Gerchberg algorithm both in the absence and in the presence of noise. Also, phantom experiments show good accuracy in the reconstruction of relaxation maps from a set of highly undersampled k-space observations.

  4. 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.

  5. Threshold temperature optical fibre sensors

    NASA Astrophysics Data System (ADS)

    Stasiewicz, K. A.; Musial, J. E.

    2016-12-01

    This paper presents a new approach to manufacture a threshold temperature sensor based on a biconical optical fibre taper. The presented sensor employs the influence of variable state of concentration of some isotropic materials like wax or paraffin. Application of the above- mentioned materials is an attempt to prove that there is a possibility to obtain a low-cost, repeatable and smart sensor working as an in-line element. Optical fibre taper was obtained from a standard single mode fibre (SMF28®) by using a low pressure gas burner technique. The diameter of the manufactured tapers was 6.0 ± 0.5 μm with the length of elongation equal to 30.50 ± 0.16 mm. The applied technology allowed to produce tapers with the losses of 0.183 ± 0.015 dB. Application of materials with different temperature transition points made it possible to obtain the threshold work at the temperatures connected directly with their conversion temperature. External materials at the temperatures above their melting points do not influence the propagation losses. For each of them two types of the protection area and position of the optical fibre taper were applied.

  6. 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.

  7. Syphilitic gumma arising in association with foreign material.

    PubMed

    Boyd, Alan S

    2016-11-01

    Until recently the number of patients with syphilis has been diminishing. Although that trend has reversed cases of tertiary syphilis are rare and often difficult to diagnose as a substantial number of patients will have a negative rapid plasma reagin. Histologically, cutaneous lesions in late stage syphilis exist in two forms, noduloulcerative and gummatous. Silver stains for spirochetes are almost invariably negative and, surprisingly, immunohistochemical stains are problematic as most lesions contain few, if any organisms. Presented here is a case of gummatous tertiary syphilis arising in association with foreign material deposited after a motor vehicle accident.

  8. Poorly differentiated carcinoma arising from adenolymphoma of the parotid gland

    PubMed Central

    Ferrero, Stefano; Cattaneo, Laura; Peri, Andrea; Braidotti, Paola; Cioffi, Ugo; Scaramellini, Gabriele; Ciulla, Michele M; De Simone, Matilde; Arizzi, Carmelo; Pignataro, Lorenzo

    2003-01-01

    Background There is only one previous case report of a poorly differentiated carcinoma arising from an adenolymphoma of the parotid gland (Warthin's tumour). The absence of clinical symptoms, and the aspecificity of the radiological pattern make the diagnosis very difficult. Case presentation We here report the case of a 73-year-old man with Warthin's tumour who was brought to our attention because of a swelling in the parotid region. Conclusions In this case with an atypical clinical presentation, the intra-operative examination of a frozen section of the parotid mass allowed us to diagnose the malignant tumour correctly and consequently undertake its radical excision. PMID:12533195

  9. Uniform Asymptotics of Orthogonal Polynomials Arising from Coherent States

    NASA Astrophysics Data System (ADS)

    Dai, Dan; Hu, Weiying; Wang, Xiang-Sheng

    2015-08-01

    In this paper, we study a family of orthogonal polynomials {φ_n(z)} arising from nonlinear coherent states in quantum optics. Based on the three-term recurrence relation only, we obtain a uniform asymptotic expansion of φ_n(z) as the polynomial degree n tends to infinity. Our asymptotic results suggest that the weight function associated with the polynomials has an unusual singularity, which has never appeared for orthogonal polynomials in the Askey scheme. Our main technique is the Wang and Wong's difference equation method. In addition, the limiting zero distribution of the polynomials φ_n(z) is provided.

  10. 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.

  11. Endometrioid adenocarcinoma arising from endometriosis of the rectosigmoid.

    PubMed

    Kobayashi, Shigeru; Sasaki, Morio; Goto, Tatsuya; Asakage, Naoki; Sekine, Masayuki; Suzuki, Takahisa; Tsukada, Kenji; Yamasaki, Shigetaka; Ukawa, Shiro

    2010-01-01

    A case of endometrioid adenocarcinoma supposedly arising from endometriosis of the rectum is reported. Malignant transformation is uncommon but a well-known complication of endometriosis. In the present case, it was proved by histopathological findings and immunophenotype such as cytokeratin7+/cytokeratin20-/estrogen receptor+. The cause of rectal endometriosis in this case might have been related with previously received hormone replacement therapy for ovarian endometriosis. Following surgical removal of the lesion, this patient underwent adjuvant chemotherapy with paclitaxel and carboplatin, although this kind of therapy is still controversial as to its effectiveness.

  12. 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

  13. 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.

  14. Fluctuation scaling in the visual cortex at threshold.

    PubMed

    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)S^{2}+(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.

  15. Sebaceous carcinoma arising in mature cystic teratoma of ovary.

    PubMed

    An, Hyo Jeong; Jung, Yong Han; Yoon, Hye Kyoung; Jung, Soo Jin

    2013-08-01

    Roughly 1% of mature cystic teratomas undergo malignant transformation. In particular, cutaneous-type adnexal neoplasms may occur in mature cystic teratomas. Sebaceous carcinomas, which arise from mature cystic teratomas, have rarely been observed, with only seven cases previously reported. Here, we present a case of a 69-year-old female who had pelvic pain for two weeks and who subsequently underwent bilateral salpingo-oophorectomy and hysterectomy. Her left ovary showed a unilocular cyst, measuring 22.0 cm in diameter, filled with sebaceous material and a few hairs. A luminally-protruding solid mass measuring 4.0 cm in diameter was also noted. Microscopic findings revealed lobular or diffusely arranged basophilic, atypical sebaceous cells connected to a typical mature cystic teratoma. Tumor cells demonstrated positive immunoreactivity for high molecular weight cytokeratin, cytokeratin 7, cytokeratin 19, epithelial membrane antigen, and carcinoembryonic antigen. Here, we present a case of sebaceous carcinoma arising from a mature cystic teratoma along with a review of previously published reports.

  16. Giant cell tumor of soft tissue arising in breast.

    PubMed

    May, Steve A; Deavers, Michael T; Resetkova, Erika; Johnson, Deborah; Albarracin, Constance T

    2007-10-01

    Primary giant cell tumor of soft tissue (GCT-ST) arising in breast is exceedingly rare. We report a case of a 60-year-old woman with a primary breast giant cell tumor that appeared histologically identical to giant cell tumor of bone and had a clinically malignant course. The patient presented with a cystic mass of the breast, suspected on imaging to be an organizing hematoma, possibly related to previous injury. Histopathological evaluation revealed a neoplasm composed of mononuclear cells admixed with osteoclast-like giant cells resembling giant cell tumor of bone. Immunohistochemical staining was positive for CD68, smooth muscle actin, and vimentin, but was negative for a panel of epithelial and additional muscle markers. These features were most consistent with GCT-ST, an uncommon neoplasm of low malignant potential. Despite aggressive surgical treatment achieving clear surgical margins, the patient expired with pulmonary metastases within a year of her initial presentation. This case demonstrates the difficulty of predicting clinical behavior of GCT-ST of breast on the basis of histological features and depth of tumor alone. To our knowledge, this is the first case report of a GCT-ST arising in the breast associated with a fatal outcome. The distinction of this entity from other more common primary breast tumors with giant cell morphology is also emphasized.

  17. High-Grade Leiomyosarcoma Arising in a Previously Replanted Limb

    PubMed Central

    Pan, Tiffany J.; Pantanowitz, Liron; Weiss, Kurt R.

    2015-01-01

    Sarcoma development has been associated with genetics, irradiation, viral infections, and immunodeficiency. Reports of sarcomas arising in the setting of prior trauma, as in burn scars or fracture sites, are rare. We report a case of a leiomyosarcoma arising in an arm that had previously been replanted at the level of the elbow joint following traumatic amputation when the patient was eight years old. He presented twenty-four years later with a 10.8 cm mass in the replanted arm located on the volar forearm. The tumor was completely resected and pathology examination showed a high-grade, subfascial spindle cell sarcoma diagnosed as a grade 3 leiomyosarcoma with stage pT2bNxMx. The patient underwent treatment with brachytherapy, reconstruction with a free flap, and subsequently chemotherapy. To the best of our knowledge, this is the first case report of leiomyosarcoma developing in a replanted extremity. Development of leiomyosarcoma in this case could be related to revascularization, scar formation, or chronic injury after replantation. The patient remains healthy without signs of recurrence at three-year follow-up. PMID:26366310

  18. Trichoepithelioma Arising in an Ovarian Mature Cystic Teratoma

    PubMed Central

    Nakayama, Satoru; Muto, Haruka; Shimizu, Shinichi; Otsuki, Yoshiro; Adachi, Hiroshi; Murakoshi, Takeshi

    2016-01-01

    Here, we report an extremely rare case of trichoepithelioma (TE)—a benign epithelial tumor originating from the outer root sheath of a hair follicle—arising in an ovarian mature cystic teratoma (MCT) with fluorodeoxyglucose-positron emission tomography (FDG-PET) findings. A 48-year-old Japanese woman presented to our hospital for her annual follow-up of adenomyosis. Ultrasonography and magnetic resonance imaging revealed a left ovarian tumor with irregular-shaped septum, which was suspicious of malignancy. However, tumor marker levels were within normal range. On FDG-PET, the maximum standardized uptake value (SUVmax) of the tumor was 2.9. Laparotomy with left salpingooophorectomy was performed. Pathologic examination revealed the probability of TE, rather than basal cell carcinoma (BCC), arising in an ovarian MCT. After five years of follow-up, the patient had no sign of recurrence. The FDG-PET SUVmax was low in TE, as with other benign tumor. However, future investigation is needed to evaluate the findings of FDG-PET imaging in TE cases. PMID:28127486

  19. 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.

  20. Basal Cell Carcinoma Arising in a Breast Augmentation Scar.

    PubMed

    Edwards, Lisa R; Cresce, Nicole D; Russell, Mark A

    2017-04-01

    We report a case of a 46-year-old female who presented with a persistent lesion on the inferior right breast. The lesion was located within the scar from a breast augmentation procedure 12 years ago. The lesion had been treated as several conditions with no improvement. Biopsy revealed a superficial and nodular basal cell carcinoma, and the lesion was successfully removed with Mohs micrographic surgery. Basal cell carcinoma arising in a surgical scar is exceedingly rare with only 13 reported cases to date. This is the first reported case of basal cell carcinoma arising in a breast augmentation scar. We emphasize the importance of biopsy for suspicious lesions or those refractory to treatment, particularly those lesions that form within a scar. Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

  1. Threshold phenomena in soft matter

    NASA Astrophysics Data System (ADS)

    Huang, Zhibin

    Although two different fields are covered, this thesis is mainly focused on some threshold behaviors in both liquid crystal field and fluid dynamic systems. A method of rubbed polyimide is used to obtain pretilt. Sufficiently strong rubbing of a polyimide (SE-1211) results in a large polar pretilt of liquid crystal director with respect to the homeotropic orientation. There exists a threshold rubbing strength required to induce nonzero pretilt. For the homologous liquid crystal series alkyl-cyanobyphenyl, we found that the threshold rubbing strength is a monotonic function of the number of methylene units. A dual easy axis model is then used to explain the results. Freedericksz transition measurements have been used to determine the quadratical and quartic coefficients associated with the molecules' tilt with respect to the layer normal in surface-induced smectic layers in the nematic phase above the smectic-A-nematic phase transition temperature. Both the quadratic and quartic coefficients are consistent with the scaling relationship as predicted in theory, and their ratio is approximately constant. A Rayleigh-Taylor instability experiment is performed by using a magnetic field gradient to draw down a low density but highly paramagnetic fluid below a more dense fluid in a Hele-Shaw cell. When turning off the magnetic field, the RT instability occurs in situ and the growth of the most unstable wavevector is measured as a function of time. The wavelength of the RT instability along with the growth rate was measured as a function of capillary number (which is related to the density difference and interfacial tension between two fluids). A theory for the instability that permits different viscosities for two immiscible fluids was developed, and good agreement was found with the experimental results. The technique of magnetic levitation promises to broaden significantly the accessible parameter space of gravitational interfacial instability experiments. A method is

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

    PubMed

    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.

  3. 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

  4. Rejection Thresholds in Chocolate Milk: Evidence for Segmentation.

    PubMed

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

    2012-10-01

    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.

  5. 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.

  6. 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.

  7. 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.

  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. Syringocystadenoma Papilliferum of the Scalp Arising from a Nevus Sebaceous

    PubMed Central

    Chandramouli, Mathangi; Sarma, Digvijay; Tejaswy, Kapil; Rodrigues, Gabriel

    2016-01-01

    Syringocystadenoma papilliferum (SCAP) is a rare, benign tumour with varied presentations that arises from the apocrine glands and at times can lead to a diagnostic dilemma. A 53-year-old male presented with a 40-year history of a scalp nodule and a recent 2-year change in its character, and a sanguinopurulent discharge. Examination revealed a 4 cm × 2 cm firm nodule upon left side of the scalp vertex, actively discharging pus and blood. No regional lymph nodes were noticeably palpable. Incision biopsy performed elsewhere showed evidence of a squamous cell carcinoma-in-situ. He underwent a wide local excision with a bilobed flap reconstruction. Histopathologically, the lesion was reported to be SCAP. On follow-up, the patient has since remained asymptomatic with an acceptable cosmetic recovery. PMID:27761094

  10. 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.

  11. Melanotic neuroectodermal tumor of infancy arising in the temporal bone.

    PubMed

    Zhang, Jian-guo; Zhao, Rui-jiao; Kong, Ling-fei

    2015-04-01

    Melanotic neuroectodermal tumor of infancy is a rare melanin-containing neoplasm with locally aggressive and rapid expansile growth, usually involving the maxilla, skull, and mandible of early infancy. Radical surgery is critical for a long-term outcome. We present a case of 14-month-old girl with rapid-growing subcutaneous mass arising in the right temporal bone and extending intracranially on computed tomographic scan. Radical surgery was performed. A brownish-black tumor composed of large pigmented epithelioid cells, positive for cytokeratins and HMB-45, and nests of small neuroblast-like cells positive for neuron-specific enolase and synaptophysin, was diagnosed as melanotic neuroectodermal tumor of infancy. The patient remained well without evidence of recurrence for 1 year after surgery. Clinicopathological features, management alternatives and outcome were discussed.

  12. Lymphatic vessels arise from specialized angioblasts within a venous niche.

    PubMed

    Nicenboim, J; Malkinson, G; Lupo, T; Asaf, L; Sela, Y; Mayseless, O; Gibbs-Bar, L; Senderovich, N; Hashimshony, T; Shin, M; Jerafi-Vider, A; Avraham-Davidi, I; Krupalnik, V; Hofi, R; Almog, G; Astin, J W; Golani, O; Ben-Dor, S; Crosier, P S; Herzog, W; Lawson, N D; Hanna, J H; Yanai, I; Yaniv, K

    2015-06-04

    How cells acquire their fate is a fundamental question in developmental and regenerative biology. Multipotent progenitors undergo cell-fate restriction in response to cues from the microenvironment, the nature of which is poorly understood. In the case of the lymphatic system, venous cells from the cardinal vein are thought to generate lymphatic vessels through trans-differentiation. Here we show that in zebrafish, lymphatic progenitors arise from a previously uncharacterized niche of specialized angioblasts within the cardinal vein, which also generates arterial and venous fates. We further identify Wnt5b as a novel lymphatic inductive signal and show that it also promotes the ‘angioblast-to-lymphatic’ transition in human embryonic stem cells, suggesting that this process is evolutionarily conserved. Our results uncover a novel mechanism of lymphatic specification, and provide the first characterization of the lymphatic inductive niche. More broadly, our findings highlight the cardinal vein as a heterogeneous structure, analogous to the haematopoietic niche in the aortic floor.

  13. Sphenoid esthesioneuroblastoma arising from the hindmost olfactory filament.

    PubMed

    Matsunaga, Mami; Nakagawa, Takayuki; Sakamoto, Tatsunori; Ito, Juichi

    2015-04-01

    Esthesioneuroblastoma (ENB), or olfactory neuroblastoma, is a rare malignant neoplasm arising from the olfactory neuroepithelium. Typically, ENBs are found in the olfactory cleft with extension to the ethmoid sinuses or anterior skull base. Here we report a case of ENB located in the sphenoid sinus, which had been considered as an ectopic ENB. However, endoscopic resection revealed the continuity of the tumor with the hindmost olfactory filament. The present case suggests that an ENB in the sphenoid sinus was not ectopic, but arose from the normal olfactory neuroepithelium. This continuity of the ENB with this filament indicated that the tumor was not ectopic, and that there was possible tumor invasion into the olfactory neuroepithelium in the cribriform niche. Therefore, pathological examination of the olfactory neuroepithelium in the cribriform niche may be necessary in case of sphenoid ENBs.

  14. 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.

  15. Contextuality Scenarios Arising from Networks of Stochastic Processes

    NASA Astrophysics Data System (ADS)

    Iglesias, Rodrigo; Tohmé, Fernando; Auday, Marcelo

    2016-10-01

    An empirical model is a generalization of a probability space. It consists of a simplicial complex of subsets of a class 𝒳 of random variables such that each simplex has an associated probability distribution. The ensuing marginalizations are coherent, in the sense that the distribution on a face of a simplex coincides with the marginal of the distribution over the entire simplex. An empirical model is called contextual if its distributions cannot be obtained by marginalizing a joint distribution over 𝒳. Contextual empirical models arise naturally in quantum theory, giving rise to some of its counter -intuitive statistical consequences. In this paper, we present a different and classical source of contextual empirical models: the interaction among many stochastic processes. We attach an empirical model to the ensuing network in which each node represents an open stochastic process with input and output random variables. The statistical behaviour of the network in the long run makes the empirical model generically contextual and even strongly contextual.

  16. Surprises and pitfalls arising from (pseudo)symmetry

    SciTech Connect

    Zwart, Peter H.; Grosse-Kunstleve, Ralf W.; Lebedev, Andrey A.; Murshudov, Garib N.; Adams, Paul D.

    2008-01-01

    The presence of pseudosymmetry can cause problems in structure determination and refinement. The relevant background and representative examples are presented. It is not uncommon for protein crystals to crystallize with more than a single molecule per asymmetric unit. When more than a single molecule is present in the asymmetric unit, various pathological situations such as twinning, modulated crystals and pseudo translational or rotational symmetry can arise. The presence of pseudosymmetry can lead to uncertainties about the correct space group, especially in the presence of twinning. The background to certain common pathologies is presented and a new notation for space groups in unusual settings is introduced. The main concepts are illustrated with several examples from the literature and the Protein Data Bank.

  17. Child protection reports: key issues arising for public health nurses.

    PubMed

    Hanafin, Sinead

    2013-10-01

    Similar to other countries, there have been a number of high-profile reports into past and recent cases of child abuse and neglect in Ireland. The most recent of these have been the Monageer Inquiry, the Ryan Report, the Roscommon Child Care Case and the Report of the Independent Child Death Review Group. An analysis of these reports highlights the critical role played by public health nurses with troubled families. It also makes explicit key issues that consistently emerge as problematic in terms of professional practice. This paper summarises the main findings of the reports as they relate to the public health nursing service and identifies key themes emerging along with recommendations arising. The emerging themes relate to assessment, early intervention, record keeping, communication and interdisciplinary working and the role of public health nursing management.

  18. Relationship between threshold and suprathreshold perception of position and stereoscopic depth.

    PubMed

    Patel, Saumil S; Bedell, Harold E; Tsang, Dorcas K; Ukwade, Michael T

    2009-04-01

    We seek to determine the relationship between threshold and suprathreshold perception for position offset and stereoscopic depth perception under conditions that elevate their respective thresholds. Two threshold-elevating conditions were used: (1) increasing the interline gap and (2) dioptric blur. Although increasing the interline gap increases position (Vernier) offset and stereoscopic disparity thresholds substantially, the perception of suprathreshold position offset and stereoscopic depth remains unchanged. Perception of suprathreshold position offset also remains unchanged when the Vernier threshold is elevated by dioptric blur. We show that such normalization of suprathreshold position offset can be attributed to the topographical-map-based encoding of position. On the other hand, dioptric blur increases the stereoscopic disparity thresholds and reduces the perceived suprathreshold stereoscopic depth, which can be accounted for by a disparity-computation model in which the activities of absolute disparity encoders are multiplied by a Gaussian weighting function that is centered on the horopter. Overall, the statement "equal suprathreshold perception occurs in threshold-elevated and unelevated conditions when the stimuli are equally above their corresponding thresholds" describes the results better than the statement "suprathreshold stimuli are perceived as equal when they are equal multiples of their respective threshold values."

  19. On the probability summation model for laser-damage thresholds

    NASA Astrophysics Data System (ADS)

    Clark, Clifton D.; Buffington, Gavin D.

    2016-01-01

    This paper explores the probability summation model in an attempt to provide insight to the model's utility and ultimately its validity. The model is a statistical description of multiple-pulse (MP) damage trends. It computes the probability of n pulses causing damage from knowledge of the single-pulse dose-response curve. Recently, the model has been used to make a connection between the observed n trends in MP damage thresholds for short pulses (<10 μs) and experimental uncertainties, suggesting that the observed trend is an artifact of experimental methods. We will consider the correct application of the model in this case. We also apply this model to the spot-size dependence of short pulse damage thresholds, which has not been done previously. Our results predict that the damage threshold trends with respect to the irradiated area should be similar to the MP damage threshold trends, and that observed spot-size dependence for short pulses seems to display this trend, which cannot be accounted for by the thermal models.

  20. 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'.

  1. Rhabdomyosarcoma arising in the hand or foot: a clinicopathologic analysis.

    PubMed

    Miller, Dylan V; Coffin, Cheryl M; Zhou, Holly

    2004-01-01

    Rhabdomyosarcomas (RMS) arising at different anatomic sites have distinct clinicopathologic features that affect prognosis and outcome. RMS arising in the extremities generally have a worse prognosis. Case reports and anecdotal experience suggests the possibility that RMS of the hand or foot (RMSHF) may behave even more aggressively than RMS elsewhere in the extremities. This study describes clinicopathologic features and outcome of RMSHF. Charts and pathologic material from RMSHF cases from institutional files over a 32-year interval were reviewed. Additional cases from published reports and series over a 42-year interval were identified by a MEDLINE search. Pertinent clinicopathologic features for each case were compiled. Survival analysis and other data from these patients were compared with previously reported statistics in the literature for RMS at other anatomic sites, including elsewhere in the extremities. Six patients from the institutional files and 46 from published reports were identified. A number of adverse prognostic indicators were observed in the majority of these patients including alveolar morphology (86%) and distant metastasis at presentation (63%). Despite the aggressive nature of these tumors, the majority were smaller than 5 cm (61%). A propensity was observed for metastases to unusual sites such as breast, ovary, testis, pancreas, and kidney. The median survival was 19 months, and the 5-year survival was 27%. While these may reflect a constellation of findings related to site, it is also possible that alveolar histology is the main influence. RMSHF can present as a very small primary tumor with clinically evident or occult metastatic disease. Whether this reflects the location, the predominantly alveolar histologic type, or a molecular genetic subtype will require further analysis. Patients presenting with RMSHF should be thoroughly evaluated for occult metastases at the time of diagnosis and followed closely throughout treatment for

  2. Estimation of measurement uncertainty arising from manual sampling of fuels.

    PubMed

    Theodorou, Dimitrios; Liapis, Nikolaos; Zannikos, Fanourios

    2013-02-15

    Sampling is an important part of any measurement process and is therefore recognized as an important contributor to the measurement uncertainty. A reliable estimation of the uncertainty arising from sampling of fuels leads to a better control of risks associated with decisions concerning whether product specifications are met or not. The present work describes and compares the results of three empirical statistical methodologies (classical ANOVA, robust ANOVA and range statistics) using data from a balanced experimental design, which includes duplicate samples analyzed in duplicate from 104 sampling targets (petroleum retail stations). These methodologies are used for the estimation of the uncertainty arising from the manual sampling of fuel (automotive diesel) and the subsequent sulfur mass content determination. The results of the three methodologies statistically differ, with the expanded uncertainty of sampling being in the range of 0.34-0.40 mg kg(-1), while the relative expanded uncertainty lying in the range of 4.8-5.1%, depending on the methodology used. The estimation of robust ANOVA (sampling expanded uncertainty of 0.34 mg kg(-1) or 4.8% in relative terms) is considered more reliable, because of the presence of outliers within the 104 datasets used for the calculations. Robust ANOVA, in contrast to classical ANOVA and range statistics, accommodates outlying values, lessening their effects on the produced estimates. The results of this work also show that, in the case of manual sampling of fuels, the main contributor to the whole measurement uncertainty is the analytical measurement uncertainty, with the sampling uncertainty accounting only for the 29% of the total measurement uncertainty.

  3. 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.

  4. Genetics Home Reference: multiple familial trichoepithelioma

    MedlinePlus

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

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

    SciTech Connect

    Rott, Carsten; In, Seongjin; Kumar, Jason; Yaylali, David E-mail: seongjin.in@gmail.com E-mail: yaylali@email.arizona.edu

    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.

  6. 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.

  7. Thresholds for Cenozoic bipolar glaciation.

    PubMed

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

    2008-10-02

    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

  8. Optimizing Systems of Threshold Detection Sensors

    DTIC Science & Technology

    2008-03-01

    mean of the "no event" distribution, we use mathematical nonlinear programming techniques to determine appropriate individual thresholds to maximize...decreases in all thresholds (less than five to ten percent) result in modest nonlinear percentage increases in detection performance (again, less than ten...level. In this thesis, we develop a model using nonlinear mathematical programming techniques to determine appropriate individual thresholds at

  9. Required thermal thresholds during transport of animals.

    PubMed

    Schrama, J W; van der Hel, W; Gorssen, J; Henken, A M; Verstegen, M W; Noordhuizen, J P

    1996-09-01

    Conditions (total complex of stressors) during the transport of animals vary strongly between and within transports. Adverse climatic conditions are stressors that animals have to face during transport. The thermoregulation of animals id discussed with respect to threshold values for optimal climatic conditions. These thermal thresholds depend on animal related factors and environmental conditions. The specific impact of transport conditions, such as food and water deprivation, high stocking density, high humidity and high air velocity, on thermal thresholds are described.

  10. GHRS Side 2 Threshold Adjustment - 4

    NASA Astrophysics Data System (ADS)

    Skapik, Joe

    1994-01-01

    This test will determine the optimal, non-standard discriminator thresholds for the few anomalous channels on HRS detector 2. A 15 second flat field observation followed by a 210 second dark count is performed at each of 10 discriminator threshold values for each detector. The result of the test will be the optimal threshold values to be entered into the PDB. Edited 4/30/91 to add comments to disable/re-enable cross-talk tables.

  11. GHRS Side 1 Threshold Adjustment - 4

    NASA Astrophysics Data System (ADS)

    Skapik, Joe

    1994-01-01

    This test will determine the optimal, non-standard discriminator thresholds for the few anomalous channels on HRS detector 1. A 15 second flat field observation followed by a 210 second dark count is performed at each of 10 discriminator threshold values for each detector. The result of the test will be the optimal threshold values to be entered into the PDB. Edited 4/30/91 to add comments to disable/re-enable cross-talk tables.

  12. Sarcomatoid carcinoma arising in the congenital pigmented nevus after treatment with carbon dioxide snow freezing method.

    PubMed

    Nakajima, Rina; Komine, Mayumi; Miyamoto, Yukiko; Fusumae, Takayuki; Fujita, Yurika; Maekawa, Takeo; Murata, Satoru; Fukushima, Noriyoshi; Ohtsuki, Mamitaro

    2015-11-01

    We report a case of sarcomatoid carcinoma of the skin in a 63-year-old man who was treated with the carbon dioxide snow freezing method for a huge congenital pigmented nevus that extended from the right upper extremity to the right trunk during childhood. He had an exophytic red tumor on the nevus in the right upper extremity that grew slowly for 4 years and rapidly recently. Histological and immunohistochemical studies revealed both epithelial and mesenchymal malignancy in the same tumor. The epithelial component was composed of basaloid cells forming multiple nests with peripheral palisading, positive for keratins and BerEP4, implying basal cell carcinoma. The mesenchymal component was composed of spindle-shaped cells negative for keratins and positive for vimentin, suggesting sarcoma. This is, to our knowledge, the first report of sarcomatoid carcinoma arising in the primary pigmented nevus that had been treated by the carbon dioxide snow freezing method.

  13. Parathyroid adenoma arising within the sternocleidomastoid muscle: a rare complication of autotransplantation.

    PubMed

    Touska, Philip; Srikanthan, Ahgi; Amarasinghe, Kavita; Jawad, Susan

    2016-07-20

    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.

  14. Automatic threshold selection using histogram quantization

    NASA Astrophysics Data System (ADS)

    Wang, Yue; Adali, Tulay; Lo, Shih-Chung B.

    1997-04-01

    An automatic threshold selection method is proposed for biomedical image analysis based on a histogram coding scheme. The threshold values can be determined based on the well-known Lloyd-Max scalar quantization rule, which is optimal in the sense of achieving minimum mean-square-error distortion. An iterative self-organizing learning rule is derived to determine the threshold levels. The rule does not require any prior information about the histogram, hence is fully automatic. Experimental results show that this new approach is easy to implement yet is highly efficient, robust with respect to noise, and yields reliable estimates of the threshold levels.

  15. 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.

  16. 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.

  17. Exhaustive Thresholds and Resistance Checkpoints

    NASA Technical Reports Server (NTRS)

    Easton, Charles; Khuzadi, Mbuyi

    2008-01-01

    Once deployed, all intricate systems that operate for a long time (such as an airplane or chemical processing plant) experience degraded performance during operational lifetime. These can result from losses of integrity in subsystems and parts that generally do not materially impact the operation of the vehicle (e.g., the light behind the button that opens the sliding door of the minivan). Or it can result from loss of more critical parts or subsystems. Such losses need to be handled quickly in order to avoid loss of personnel, mission, or part of the system itself. In order to manage degraded systems, knowledge of its potential problem areas and the means by which these problems are detected should be developed during the initial development of the system. Once determined, a web of sensors is employed and their outputs are monitored with other system parameters while the system is in preparation or operation. Just gathering the data is only part of the story. The interpretation of the data itself and the response of the system must be carefully developed as well to avoid a mishap. Typically, systems use a test-threshold-response paradigm to process potential system faults. However, such processing sub-systems can suffer from errors and oversights of a consistent type, causing system aberrant behavior instead of expected system and recovery operations. In our study, we developed a complete checklist for determining the completeness of a fault system and its robustness to common processing and response difficulties.

  18. 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?

  19. 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?

  20. HMM-ModE – Improved classification using profile hidden Markov models by optimising the discrimination threshold and modifying emission probabilities with negative training sequences

    PubMed Central

    Srivastava, Prashant K; Desai, Dhwani K; Nandi, Soumyadeep; Lynn, Andrew M

    2007-01-01

    Background Profile Hidden Markov Models (HMM) are statistical representations of protein families derived from patterns of sequence conservation in multiple alignments and have been used in identifying remote homologues with considerable success. These conservation patterns arise from fold specific signals, shared across multiple families, and function specific signals unique to the families. The availability of sequences pre-classified according to their function permits the use of negative training sequences to improve the specificity of the HMM, both by optimizing the threshold cutoff and by modifying emission probabilities to minimize the influence of fold-specific signals. A protocol to generate family specific HMMs is described that first constructs a profile HMM from an alignment of the family's sequences and then uses this model to identify sequences belonging to other classes that score above the default threshold (false positives). Ten-fold cross validation is used to optimise the discrimination threshold score for the model. The advent of fast multiple alignment methods enables the use of the profile alignments to align the true and false positive sequences, and the resulting alignments are used to modify the emission probabilities in the original model. Results The protocol, called HMM-ModE, was validated on a set of sequences belonging to six sub-families of the AGC family of kinases. These sequences have an average sequence similarity of 63% among the group though each sub-group has a different substrate specificity. The optimisation of discrimination threshold, by using negative sequences scored against the model improves specificity in test cases from an average of 21% to 98%. Further discrimination by the HMM after modifying model probabilities using negative training sequences is provided in a few cases, the average specificity rising to 99%. Similar improvements were obtained with a sample of G-Protein coupled receptors sub-classified with

  1. 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

  2. Quarter-Power Scaling of Primate Hearing Thresholds With Neocortex Volume

    NASA Astrophysics Data System (ADS)

    Harrison, Michael J.

    2004-03-01

    Primate threshold hearing levels as a function of frequency are calculated from noise that arises through thermal excitation of damped sound waves in a cylindrical meatus terminated by a rigid eardrum. Fourier integral analysis of noise pressure within masking frequency bands that span threshold hearing is related to the time integral of noise pressure incident on the eardrum in a single period of threshold signal. The ratio of the latter to former quantity is expressed in terms of theoretical decibel thresholds scaled by coupling constants that relate physical noise excitation to perceived threshold hearing at each audiofrequency. The theory is normalized to a common clinical datum for humans and macaques at a single frequency, and then captures the main features of clinical threshold data [1] throughout the full range of frequencies reported in observations on humans and monkeys. It appears that such coupling constants for humans and macaque monkeys show a 1/4 power scaling law behavior in terms of neocortex volume, when due account is also taken of differences in meatus size in the generation of thermal noise pressure. 1. L.L. Jackson, R.S.Heffner, and H.E.Heffner, J.Acoust.Soc.Am. 106(5),3017, (1999).

  3. Determining The Electromyographic Fatigue Threshold Following a Single Visit Exercise Test.

    PubMed

    Galen, Sujay S; Guffey, Darren R; Coburn, Jared W; Malek, Moh H

    2015-07-27

    Theoretically, the electromyographic (EMG) fatigue threshold is the exercise intensity an individual can maintain indefinitely without the need to recruit more motor units which is associated with an increase in the EMG amplitude. Although different protocols have been used to estimate the EMG fatigue threshold they require multiple visits which are impractical for a clinical setting. Here, we present a protocol for estimating the EMG fatigue threshold for cycle ergometry which requires a single visit. This protocol is simple, convenient, and completed within 15-20 min, therefore, has the potential to be translated into a tool that clinicians can use in exercise prescription.

  4. 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.

  5. Impedance control reduces instability that arises from motor noise.

    PubMed

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

    2009-10-07

    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 endpoint impedance of the arm in the absence of active force fields but in the presence of instability arising from task geometry and signal-dependent noise (SDN) 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 tradeoff between maximizing the mechanical stability and minimizing the destabilizing effects of SDN. Therefore, it would have been suboptimal 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.

  6. 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.

  7. 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.

  8. Sound radiation quantities arising from a resilient circular radiator.

    PubMed

    Aarts, Ronald M; Janssen, Augustus J E M

    2009-10-01

    Power series expansions in ka are derived for the pressure at the edge of a radiator, the reaction force on the radiator, and the total radiated power arising from a harmonically excited, resilient, flat, circular radiator of radius a in an infinite baffle. The velocity profiles on the radiator are either Stenzel functions (1-(sigma/a)2)n, with sigma the radial coordinate on the radiator, or linear combinations of Zernike functions Pn(2(sigma/a)2-1), with Pn the Legendre polynomial of degree n. Both sets of functions give rise, via King's integral for the pressure, to integrals for the quantities of interest involving the product of two Bessel functions. These integrals have a power series expansion and allow an expression in terms of Bessel functions of the first kind and Struve functions. Consequently, many of the results in [M. Greenspan, J. Acoust. Soc. Am. 65, 608-621 (1979)] are generalized and treated in a unified manner. A foreseen application is for loudspeakers. The relation between the radiated power in the near-field on one hand and in the far field on the other is highlighted.

  9. Thyroid gland metastasis arising from breast cancer: A case report.

    PubMed

    Yang, Mei; Wang, Wei; Zhang, Chenfang

    2013-06-01

    The thyroid gland is an uncommon site for metastasis to develop and thus metastases arising from breast cancer are rarely observed. In the present study, we describe a case of a 45-year-old female with a three-year history of breast cancer who presented with a thyroid mass that was diagnosed as metastatic breast carcinoma by histopathological analysis of the subtotal thyroidectomy specimen. To ascertain the diagnosis of metastatic breast cancer, we evaluated two types of markers; those that possessed a similar expression status in the original and metastatic lesions [ER, PR and CerbB-2 (HER2/neu)], and those that are capable of differentiating between metastatic lesions and the surrounding thyroid components (TG and TTF-1). The results showed that ER, PR and CerbB-2 demonstrated a similar expression pattern in primary breast carcinoma and thyroid lesions. Meanwhile, in the thyroid lesions, the malignant cells showed negative staining for TG and TTF-1, which confirmed that lesions were not thyroid in origin. This case may prompt clinicians that although thyroid gland are uncommon metastatic site, a diagnosis of metastatic disease should be considered when new aggregates are identified in the thyroid glands and histopathological analysis may aid the diagnosis.

  10. 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.

  11. Mycobacterium fortuitum infection arising in a new tattoo.

    PubMed

    Philips, Rebecca C; Hunter-Ellul, Lindsey A; Martin, Julie E; Wilkerson, Michael G

    2014-06-15

    We report an uncommon case of a cutaneous infection with Mycobacterium fortuitum arising in a new tattoo. A 29-year-old man presented with a several month history of a non-pruritic papular eruption within a tattoo; the papules developed 1-to-2 weeks after the tattoo procedure. He denied similar symptoms with previous tattoos. He had been treated unsuccessfully with cephalexin. Histopathologic examination revealed perifollicular chronic and granulomatous inflammation, consistent with chronic folliculitis. Acid-fast bacilli culture identified Mycobacterium fortuitum complex. The patient was treated with a 2-month course of oral trimethoprim-sulfamethoxazole (160mg/800mg twice daily) and ciprofloxacin (250 mg twice daily), with clinical improvement at follow up after three weeks of the antibiotic regimen. Rapidly growing mycobacteria have emerged as a cause of tattoo-associated cutaneous infection in recent years. Diagnosis and treatment can be difficult without clinical suspicion. M. fortuitum and other rapidly growing mycobacteria should be considered in the differential diagnosis of tattoo-associated dermatologic complications.

  12. Sparse Gamma Rhythms Arising through Clustering in Adapting Neuronal Networks

    PubMed Central

    Kilpatrick, Zachary P.; Ermentrout, Bard

    2011-01-01

    Gamma rhythms (30–100 Hz) are an extensively studied synchronous brain state responsible for a number of sensory, memory, and motor processes. Experimental evidence suggests that fast-spiking interneurons are responsible for carrying the high frequency components of the rhythm, while regular-spiking pyramidal neurons fire sparsely. We propose that a combination of spike frequency adaptation and global inhibition may be responsible for this behavior. Excitatory neurons form several clusters that fire every few cycles of the fast oscillation. This is first shown in a detailed biophysical network model and then analyzed thoroughly in an idealized model. We exploit the fact that the timescale of adaptation is much slower than that of the other variables. Singular perturbation theory is used to derive an approximate periodic solution for a single spiking unit. This is then used to predict the relationship between the number of clusters arising spontaneously in the network as it relates to the adaptation time constant. We compare this to a complementary analysis that employs a weak coupling assumption to predict the first Fourier mode to destabilize from the incoherent state of an associated phase model as the external noise is reduced. Both approaches predict the same scaling of cluster number with respect to the adaptation time constant, which is corroborated in numerical simulations of the full system. Thus, we develop several testable predictions regarding the formation and characteristics of gamma rhythms with sparsely firing excitatory neurons. PMID:22125486

  13. 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.

  14. 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…

  15. 24 CFR 954.104 - Performance thresholds.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 4 2011-04-01 2011-04-01 false Performance thresholds. 954.104... DEVELOPMENT INDIAN HOME PROGRAM Applying for Assistance § 954.104 Performance thresholds. Applicants must have... HOME program must have performed adequately. In cases of previously documented deficient...

  16. 40 CFR 98.221 - 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. 98.221 Section 98.221 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Nitric Acid Production § 98.221 Reporting threshold. You must report...

  17. 40 CFR 98.251 - 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. 98.251 Section 98.251 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Petroleum Refineries § 98.251 Reporting threshold. You must report...

  18. 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…

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 40 CFR 98.421 - 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. 98.421 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...

  4. Detectability thresholds of general modular graphs

    NASA Astrophysics Data System (ADS)

    Kawamoto, Tatsuro; Kabashima, Yoshiyuki

    2017-01-01

    We investigate the detectability thresholds of various modular structures in the stochastic block model. Our analysis reveals how the detectability threshold is related to the details of the modular pattern, including the hierarchy of the clusters. We show that certain planted structures are impossible to infer regardless of their fuzziness.

  5. Thresholds for odor and nasal pungency.

    PubMed

    Cometto-Muñiz, J E; Cain, W S

    1990-11-01

    Detection thresholds were measured repeatedly for 11 chemicals in normosmic and anosmic subjects. The stimuli comprised the first eight members of the series of n-aliphatic alcohols, phenyl ethyl alcohol, pyridine, and menthol. Results showed that anosmics could detect, via pungency, all but phenyl ethyl alcohol reliably. In the aliphatic series, both odor and pungency thresholds declined with chain length in a way that implied dependence of both in part on phase distribution in the mucosa. Odor thresholds, however, declined more rapidly than pungency thresholds: the ratio of anosmics threshold/normosmics threshold increased from 23 for methanol to 10,000 for 1-octanol. The outcome of a scaling experiment employing normosmic subjects indicated that, with the exception of methanol and ethanol, pungency arose when perceived intensity reached a narrowly tuned criterion level. When thresholds were expressed as percentages of saturated vapor, an index of thermodynamic activity, thereby accounting for differences in solubility and in phase distribution in the mucosa among the various stimuli, both odor and pungency thresholds depicted a striking constancy across stimuli.

  6. 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...

  7. 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...

  8. 40 CFR 98.471 - 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. 98.471 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...

  9. 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...

  10. 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...

  11. 40 CFR 98.341 - 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. 98.341 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...

  12. 40 CFR 98.341 - 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. 98.341 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...

  13. 40 CFR 98.341 - 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. 98.341 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...

  14. 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...

  15. 40 CFR 98.341 - 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. 98.341 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...

  16. 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…

  17. Semi-empirical AGN detection threshold in spectral synthesis studies of Lyman-continuum-leaking early-type galaxies

    NASA Astrophysics Data System (ADS)

    Cardoso, Leandro S. M.; Gomes, Jean-Michel; Papaderos, Polychronis

    2016-10-01

    Various lines of evidence suggest that the cores of a large portion of early-type galaxies (ETGs) are virtually evacuated of warm ionised gas. This implies that the Lyman-continuum (LyC) radiation produced by an assumed active galactic nucleus (AGN) can escape from the nuclei of these systems without being locally reprocessed into nebular emission, which would prevent their reliable spectroscopic classification as Seyfert galaxies with standard diagnostic emission-line ratios. The spectral energy distribution (SED) of these ETGs would then lack nebular emission and be essentially composed of an old stellar component and the featureless power-law (PL) continuum from the AGN. A question that arises in this context is whether the AGN component can be detected with current spectral population synthesis in the optical, specifically, whether these techniques effectively place an AGN detection threshold in LyC-leaking galaxies. To quantitatively address this question, we took a combined approach that involves spectral fitting with Starlight of synthetic SEDs composed of stellar emission that characterises a 10 Gyr old ETG and an AGN power-law component that contributes a fraction 0 ≤ xAGN < 1 of the monochromatic luminosity at λ0 = 4020 Å. In addition to a set of fits for PL distributions Fν ∝ ν- α with the canonical α = 1.5, we used a base of multiple PLs with 0.5 ≤ α ≤ 2 for a grid of synthetic SEDs with a signal-to-noise ratio of 5-103. Our analysis indicates an effective AGN detection threshold at xAGN ≃ 0.26, which suggests that a considerable fraction of ETGs hosting significant accretion-powered nuclear activity may be missing in the AGN demographics.

  18. Thresholds of cutaneous afferents related to perceptual threshold across the human foot sole

    PubMed Central

    Strzalkowski, Nicholas D. J.; Mildren, Robyn L.

    2015-01-01

    Perceptual thresholds are known to vary across the foot sole, despite a reported even distribution in cutaneous afferents. Skin mechanical properties have been proposed to account for these differences; however, a direct relationship between foot sole afferent firing, perceptual threshold, and skin mechanical properties has not been previously investigated. Using the technique of microneurography, we recorded the monofilament firing thresholds of cutaneous afferents and associated perceptual thresholds across the foot sole. In addition, receptive field hardness measurements were taken to investigate the influence of skin hardness on these threshold measures. Afferents were identified as fast adapting [FAI (n = 48) or FAII (n = 13)] or slowly adapting [SAI (n = 21) or SAII (n = 20)], and were grouped based on receptive field location (heel, arch, metatarsals, toes). Overall, perceptual thresholds were found to most closely align with firing thresholds of FA afferents. In contrast, SAI and SAII afferent firing thresholds were found to be significantly higher than perceptual thresholds and are not thought to mediate monofilament perceptual threshold across the foot sole. Perceptual thresholds and FAI afferent firing thresholds were significantly lower in the arch compared with other regions, and skin hardness was found to positively correlate with both FAI and FAII afferent firing and perceptual thresholds. These data support a perceptual influence of skin hardness, which is likely the result of elevated FA afferent firing threshold at harder foot sole sites. The close coupling between FA afferent firing and perceptual threshold across foot sole indicates that small changes in FA afferent firing can influence perceptual thresholds. PMID:26289466

  19. Presenting evidence and summary measures to best inform societal decisions when comparing multiple strategies.

    PubMed

    Eckermann, Simon; Willan, Andrew R

    2011-07-01

    in directly presenting differences in expected net benefit (ENB). The CEA frontier, while identifying strategies that maximize ENB, only presents their probability of maximizing net benefit (NB) and, hence, fails to explain why strategies maximize ENB at any given threshold value. Third, in summarizing evidence for somewhat risk-averse societal decision making, trade-offs between the strategy maximizing ENB and other potentially optimal strategies with higher probability of maximizing NB should be presented over discrete threshold values where they arise. However, the probabilities informing these trade-offs and associated discrete threshold value regions should be derived from bilateral CEA curves to prevent confounding by other strategies inherent in multiple strategy CEA curves. Based on these findings, a series of recommendations are made for best presenting and summarizing cost-effectiveness evidence for reimbursement decisions when comparing multiple strategies, which are contrasted with advice for comparing two strategies. Implications for joint research and reimbursement decisions are also discussed.

  20. 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.

  1. Assessing Hurricane Vulnerability Changes Arising from Climate Variability and Change

    NASA Astrophysics Data System (ADS)

    Holland, G. J.; Done, J.; Bruyere, C.; NESL Regional Climate Research Group

    2011-12-01

    The vulnerability of a community to hurricane impacts depends on a diverse array of factors. At the community level these include: the quality of their infrastructure and its ability to withstand a hurricane impact, their level of preparedness and ability to respond appropriately to a threat, and their capacity to recover after an impact. Developing and maintaining these at an appropriate level requires a dedicated and sustained effort that results in considerable cost to the community. This cost must be balanced against the likely damage from an impact and its frequency of occurrence. And therein lies the rub; traditional assessment techniques use past cyclone data that: are subject to various levels of data deficiencies, cannot account for changes that might arise from climate change, may cover too short a time period to adequately account for long-term climate variability or to enable assessment of the very rare extreme events. This talk will address current approaches to assessing these deficiencies. We will first discuss the cyclone parameters that are important to assessing impact and show that intensity alone is only one part. For wind it is duration, extent and gustiness that are crucial, and often the rainfall is the dominant impact. These also depend on hurricane size, translation speed and local terrain; and the level of storm surge is also dependent on bathymetry and coastline details. Second, We will address how numerical models are becoming a valuable tool in assessing these features for future climate. The talk will conclude with a summary of the current state of agreement, and disagreement, on likely future changes.

  2. 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

  3. Transversely isotropic elasticity and poroelasticity arising from thin isotropic layers

    SciTech Connect

    Berryman, J.G.

    1997-07-01

    Since the classic work of Postma [1955] and Backus [1962], much has been learned about elastic constants in vertical transversely isotropic (VTI) media when the anisotropy is due to fine layering of isotropic elastic materials. However, new results are still being discovered. For example, the P-wave anisotropy parameter c{sub 11}/c{sub 33} lies in the range 1/4 {<=} c{sub 11}/c{sub 33} {<=} <{lambda}+2{mu}><1/({lambda}+2{mu})>, when the layers are themselves composed of isotropic elastic materials with Lame constants {lambda} and {mu} and the vertical average of the layers is symbolized by <{center_dot}>. The lower bound corrects a result of Postma. For porous layers, 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. For isotropic and anisotropic poroelastic media, we establish 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 [1951] formulas that must be satisfied by any anisotropic poroelastic medium and found to be in complete agreement. Such results are important for applications to oil exploration using AVO (amplitude versus offset) since the presence or absence of a fluid component, as well as the nature of the fluid, is the critical issue and the ways in which the fluid influences seismic reflection data still need to be better understood.

  4. Obesity, the Endocannabinoid System, and Bias Arising from Pharmaceutical Sponsorship

    PubMed Central

    McPartland, John M.

    2009-01-01

    Background Previous research has shown that academic physicians conflicted by funding from the pharmaceutical industry have corrupted evidence based medicine and helped enlarge the market for drugs. Physicians made pharmaceutical-friendly statements, engaged in disease mongering, and signed biased review articles ghost-authored by corporate employees. This paper tested the hypothesis that bias affects review articles regarding rimonabant, an anti-obesity drug that blocks the central cannabinoid receptor. Methods/Principal Findings A MEDLINE search was performed for rimonabant review articles, limited to articles authored by USA physicians who served as consultants for the company that manufactures rimonabant. Extracted articles were examined for industry-friendly bias, identified by three methods: analysis with a validated instrument for monitoring bias in continuing medical education (CME); analysis for bias defined as statements that ran contrary to external evidence; and a tally of misrepresentations about the endocannabinoid system. Eight review articles were identified, but only three disclosed authors' financial conflicts of interest, despite easily accessible information to the contrary. The Takhar CME bias instrument demonstrated statistically significant bias in all the review articles. Biased statements that were nearly identical reappeared in the articles, including disease mongering, exaggerating rimonabant's efficacy and safety, lack of criticisms regarding rimonabant clinical trials, and speculations about surrogate markers stated as facts. Distinctive and identical misrepresentations regarding the endocannabinoid system also reappeared in articles by different authors. Conclusions The findings are characteristic of bias that arises from financial conflicts of interest, and suggestive of ghostwriting by a common author. Resolutions for this scenario are proposed. PMID:19333392

  5. Dracunculiasis eradication--finishing the job before surprises arise.

    PubMed

    Visser, Benjamin Jelle

    2012-07-01

    Dracunculiasis (Guinea worm disease) is a preventable waterborne parasitic disease that affects the poorest people living in remote rural areas in sub-Saharan African countries, who do not have access to safe drinking water. The Guinea Worm Eradication Program, a 25-year old campaign to rid the world of Guinea Worm disease has now reached its final stage accelerating to zero cases in all endemic countries. During the 19th and 20th centuries, dracunculiasis was common in much of Southern Asia and the African continent. The overall number of cases has been reduced tremendously by ≥99%, from the 3.32 million cases estimated to have occurred in 1986 in Africa to only 1,797 cases reported in 2010 reported in only five countries (Sudan, Mali, Ethiopia, Chad and Ghana) and Asia free of the disease. This achievement is unique in its kind--the only previously eradicated disease is smallpox, a viral infection for which vaccination was possible--and it has been achieved through primary community-based prevention and health education programs. Most efforts need to be taken in two countries, South Sudan (comprising 94% or 1,698 out of 1,797 of the cases reported world-wide in 2010) and Mali because of frequent movements of nomads in a vast area inside and outside Mali's borders. All factors favourable to dracunculiasis eradication are available including adequate financial resources, community and political support and high levels of advocacy. Thus there is no reason that this disabling parasitic disease cannot be eradicated soon before surprises arise such as new civil conflicts in currently endemic countries.

  6. 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

  7. 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

  8. 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.

  9. Ce-PROMOTED Bond Activation of Propene Probed by Mass-Analyzed Threshold Ionization Spectroscopy

    NASA Astrophysics Data System (ADS)

    Zhang, Yuchen; Kumari, Sudesh; Yang, Dong-Sheng

    2016-06-01

    The reaction of Ce + propene (CH2=CH-CH3) was carried out in a laser-ablation supersonic molecular beam source. CeC_2H_2, CeC_3H_4, CeC_3H_6, CeC_4H_6, CeC_6H10, and CeC_6H12 were identified by photoionization time-of-flight mass spectrometric measurements, and their structures and electronic states were investigated with mass-analyzed threshold ionization (MATI) spectroscopy and theoretical calculations. The metal complexes containing two or three carbon atoms were formed by the C-C bond breakage (CeC_2H_2), dehydrogenation (CeC_3H_4), or metal insertion into a C-H bond (CeC_3H_6) of a propene molecule. The larger complexes with four to six carbons are formed through secondary reactions involving C-C bond coupling and dehydrogenation. The ground electronic states of the neutral CeC_2H_2, CeC_3H_4, CeC_3H_6, and CeC_4H_6 complexes are triplets with a 4f16s1 electron configuration on the Ce center, and those of the corresponding ions are doublet with a 4f1 configuration. Their MATI spectra are much more complex than those of the corresponding La species formed in the La + propene reaction previously observed by our group. The spectral complexity arises from possibly multiple electronic transitions due to the existence of a 4f electron of the Ce atom which could be located in any one of the seven f-atomic orbitals or involved in considerable spin-orbit interactions.

  10. 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.

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

    PubMed

    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 degrees C for full bloom, and from -0.5 to 6.6 degrees C for harvest. However, the "Null" method (lower threshold set to 0 degrees C) and "Fixed Value" method (lower threshold set to -2 degrees C for full bloom and to 3 degrees 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.

  12. 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

  13. 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.

  14. Thermoregulatory response thresholds during spinal anesthesia.

    PubMed

    Kurz, A; Sessler, D I; Schroeder, M; Kurz, M

    1993-10-01

    Reportedly, during spinal anesthesia, the shivering threshold is reduced approximately 1 degree C but the vasoconstriction threshold remains normal. Such divergence between the shivering and vasoconstriction thresholds is an unusual pattern of thermoregulatory impairment and suggests that the mechanisms of impairment during regional anesthesia may be especially complex. Accordingly, we sought to define the pattern of thermoregulatory impairment during spinal anesthesia by measuring response thresholds. Seven healthy women volunteered to participate on two study days. On one day, we evaluated thermoregulatory responses to hypothermia and hyperthermia during spinal anesthesia; on the other day, responses were evaluated without anesthesia. Upper body skin temperature was kept constant throughout the study. The volunteers were warmed via the lower body and cooled by central venous infusion of cold fluid. The core temperatures triggering a sweating rate of 40 g.m-2 x h-1, a finger flow of 0.1 mL/min, and a marked and sustained increase in oxygen consumption were considered the thermoregulatory thresholds for sweating, vasoconstriction, and shivering, respectively. Spinal anesthesia significantly decreased the thresholds for vasoconstriction and shivering, and the decrease in each was approximately 0.5 degree C. The range of temperatures not triggering thermoregulatory responses (those between sweating and vasoconstriction) was 0.9 +/- 0.6 degree C during spinal anesthesia. The synchronous decrease in the shivering and vasoconstriction thresholds during spinal anesthesia is consistent with thermoregulatory impairment resulting from altered afferent thermal input.

  15. Diversity of threshold phenomena in geophysical media

    NASA Astrophysics Data System (ADS)

    Guglielmi, A. V.

    2017-01-01

    The sample analysis of threshold phenomena in the lithosphere, atmosphere, and magnetosphere is conducted. The phenomena due to the flow of electric current and pore fluid in the rocks are considered, the scenario of wind-driven generation of atmospheric electricity is suggested, and the model of the geomagnetic storm time Dst variation is analyzed. An important general conclusion consists in the fact that in the geophysical media there is a wide class of threshold phenomena that are affine with phase transitions of the second kind. These phenomena are also related to the critical transitions in self-oscillatory systems with soft self-excitation. The integral representation of bifurcation diagrams for threshold phenomena is suggested. This provides a simple way to take into account the influence of the fluctuations on the transition of a system through the threshold. Fluctuations remove singularity at the threshold point and, generally, lead to a certain shifting of the threshold. The question concerning the hard transition through the threshold and several aspects of modeling the blow-up instability which is presumed to occasionally develop in the geophysical media are discussed.

  16. Hyper-arousal decreases human visual thresholds.

    PubMed

    Woods, Adam J; Philbeck, John W; Wirtz, Philip

    2013-01-01

    Arousal has long been known to influence behavior and serves as an underlying component of cognition and consciousness. However, the consequences of hyper-arousal for visual perception remain unclear. The present study evaluates the impact of hyper-arousal on two aspects of visual sensitivity: visual stereoacuity and contrast thresholds. Sixty-eight participants participated in two experiments. Thirty-four participants were randomly divided into two groups in each experiment: Arousal Stimulation or Sham Control. The Arousal Stimulation group underwent a 50-second cold pressor stimulation (immersing the foot in 0-2° C water), a technique known to increase arousal. In contrast, the Sham Control group immersed their foot in room temperature water. Stereoacuity thresholds (Experiment 1) and contrast thresholds (Experiment 2) were measured before and after stimulation. The Arousal Stimulation groups demonstrated significantly lower stereoacuity and contrast thresholds following cold pressor stimulation, whereas the Sham Control groups showed no difference in thresholds. These results provide the first evidence that hyper-arousal from sensory stimulation can lower visual thresholds. Hyper-arousal's ability to decrease visual thresholds has important implications for survival, sports, and everyday life.

  17. 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.

  18. Red cell antibodies arising from solid organ transplants.

    PubMed

    Ramsey, G

    1991-01-01

    RBC antibodies arising from transplanted organs and directed against recipient RBCs represent a well-established immunohematologic complication of solid organ transplantation. In ABO-unmatched organs, the frequency and severity of graft antibodies and hemolysis generally increase with the size (lymphoid content) of the organ, from kidney to liver to heart-lung transplants. In the cases reviewed here, the frequency of hemolysis increased in cyclosporine-treated kidney transplant recipients and O-to-A liver transplant recipients and decreased in group AB liver transplant recipients and kidney transplant recipients receiving azathioprine or low-dose postoperative graft irradiation. Available data cannot otherwise distinguish which cyclosporine-treated recipients of ABO-unmatched kidneys and livers (30-40% of total) will develop graft antibody. There has been no conclusive effect to date of the age, race, or gender of the donor or the recipient, of cadaver versus living kidney donors, or of patients' A2 or secretor status. In a few cases of living-donor kidney grafts, the donor was the patient's mother or wife who had been exposed to the recipient's RBC antigens via pregnancy. The ABO antibodies are typically IgG, appear 7 to 10 days after transplantation, and last for about a month. If immediate-spin crossmatching is done routinely, DATs are recommended in compatibility testing after ABO-unmatched transplants. Changes in the immunosuppressive regimen, such as a change from cyclosporine therapy, have not affected the duration of these antibodies. Most patients require only transfusions for this self-limited process, but six cases of hemolysis-induced acute renal failure have been reported, and one death was attributed to complications of hemolysis. RBC or plasma exchange has been performed in a few fulminant cases. RBCs of the donor's blood type are given when antibody appears. Some workers recommend such transfusion as prophylaxis at the time of surgery, although in

  19. 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).

  20. 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.

  1. Financial networks with static and dynamic thresholds

    NASA Astrophysics Data System (ADS)

    Qiu, Tian; Zheng, Bo; Chen, Guang

    2010-04-01

    Based on the daily data of the American and Chinese stock markets, the dynamic behavior of a financial network with static and dynamic thresholds is investigated. Compared with the static threshold, the dynamic threshold suppresses the large fluctuation induced by the cross correlation of individual stock prices and leads to a stable topological structure in the dynamic evolution. Long-range time correlations are revealed for the average clustering coefficient, average degree and cross correlation of degrees. The dynamic network shows a two-peak behavior in the degree distribution.

  2. Nonlinear threshold behavior during the loss of Arctic sea ice.

    PubMed

    Eisenman, I; Wettlaufer, J S

    2009-01-06

    In light of the rapid recent retreat of Arctic sea ice, a number of studies have discussed the possibility of a critical threshold (or "tipping point") beyond which the ice-albedo feedback causes the ice cover to melt away in an irreversible process. The focus has typically been centered on the annual minimum (September) ice cover, which is often seen as particularly susceptible to destabilization by the ice-albedo feedback. Here, we examine the central physical processes associated with the transition from ice-covered to ice-free Arctic Ocean conditions. We show that although the ice-albedo feedback promotes the existence of multiple ice-cover states, the stabilizing thermodynamic effects of sea ice mitigate this when the Arctic Ocean is ice covered during a sufficiently large fraction of the year. These results suggest that critical threshold behavior is unlikely during the approach from current perennial sea-ice conditions to seasonally ice-free conditions. In a further warmed climate, however, we find that a critical threshold associated with the sudden loss of the remaining wintertime-only sea ice cover may be likely.

  3. 32 CFR 536.131 - Limitations on assessments arising from UCMJ claims.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Limitations on assessments arising from UCMJ... Military Justice § 536.131 Limitations on assessments arising from UCMJ claims. (a) Limitations on amount... provisions of Rule for Courts-Martial 1107 in a court-martial arising out of the same incident would...

  4. 28 CFR 45.2 - Disqualification arising from personal or political relationship.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Disqualification arising from personal or... RESPONSIBILITIES § 45.2 Disqualification arising from personal or political relationship. (a) Unless authorized... campaign organization, arising from service as a principal adviser thereto or a principal official...

  5. 32 CFR 536.115 - Claims procedures for claims arising overseas under international agreements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Claims procedures for claims arising overseas... Under International Agreements § 536.115 Claims procedures for claims arising overseas under... services or other Army JA offices responsible for claims that arise in countries bound by SOFA or...

  6. 32 CFR 536.107 - Scope for international agreements claims arising in the United States.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Scope for international agreements claims arising... International Agreements § 536.107 Scope for international agreements claims arising in the United States. This... claims arising out of any acts or omissions of members of a foreign military force or civilian...

  7. 32 CFR 536.136 - Scope for claims arising under the Foreign Claims Act.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Scope for claims arising under the Foreign Claims....136 Scope for claims arising under the Foreign Claims Act. (a) Application. This subpart, which is..., or property damage caused by service members or civilian employees, or claims that arise incident...

  8. 32 CFR 536.114 - Scope for claims arising overseas under international agreements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 3 2010-07-01 2010-07-01 true Scope for claims arising overseas under... International Agreements § 536.114 Scope for claims arising overseas under international agreements. (a) This section sets forth guidance on claims arising from any act or omission of soldiers or members of...

  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. 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.

  11. Effective theories and thresholds in particle physics

    SciTech Connect

    Gaillard, M.K.

    1991-06-07

    The role of effective theories in probing a more fundamental underlying theory and in indicating new physics thresholds is discussed, with examples from the standard model and more speculative applications to superstring theory. 38 refs.

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report... generation corrected for oxidation as determined using Equation TT-6 of this subpart times the global...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 40 CFR 98.181 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Lead Production § 98.181 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a lead production process and the facility meets...

  7. 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...

  8. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an adipic acid production process and the...

  9. 40 CFR 98.181 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Lead Production § 98.181 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a lead production process and the facility meets...

  10. 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...

  11. 40 CFR 98.171 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) 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...

  12. 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...

  13. 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...

  14. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) 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...

  15. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an adipic acid production process and the...

  16. 40 CFR 98.111 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.111 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a ferroalloy production process and the...

  17. 40 CFR 98.111 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Ferroalloy Production § 98.111 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a ferroalloy production process and the...

  18. 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...

  19. 40 CFR 98.171 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) 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 98.81 - 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 40 CFR 98.191 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Lime Manufacturing § 98.191 Reporting threshold. You must report GHG emissions under this subpart if your facility is a lime manufacturing plant as defined in § 98.190 and...

  7. 40 CFR 98.291 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) 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...

  8. 40 CFR 98.291 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) 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...

  9. 40 CFR 98.291 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) 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...

  10. 40 CFR 98.291 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) 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...

  11. 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...

  12. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an adipic acid production process and the...

  13. 40 CFR 98.51 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Adipic Acid Production § 98.51 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an adipic acid production process and the...

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  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, 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...

  9. 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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...

  14. 40 CFR 98.81 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) 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...

  15. 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...

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. 40 CFR 98.391 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Suppliers of Petroleum Products § 98.391 Reporting threshold. Any supplier of petroleum products who meets the requirements of § 98.2(a)(4) must report GHG emissions....

  5. 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....

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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 §...

  12. 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 §...

  13. 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 §...

  14. 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 §...

  15. 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 §...

  16. 40 CFR 98.271 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Pulp and Paper Manufacturing § 98.271 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a pulp and paper manufacturing...

  17. 40 CFR 98.271 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Pulp and Paper Manufacturing § 98.271 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a pulp and paper manufacturing...

  18. 40 CFR 98.271 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Pulp and Paper Manufacturing § 98.271 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a pulp and paper manufacturing...

  19. 40 CFR 98.271 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Pulp and Paper Manufacturing § 98.271 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a pulp and paper manufacturing...

  20. 40 CFR 98.271 - Reporting threshold.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Pulp and Paper Manufacturing § 98.271 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a pulp and paper manufacturing...

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

    DOE PAGES

    Burr, Tom; Hamada, Michael S.; Howell, John; ...

    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

  2. High Performance Magazine Acceptor Threshold Criteria

    DTIC Science & Technology

    1994-08-01

    detonation transition (DDT). To account for unknown mechanisms the term XDT is also used. Development of a design procedure to prevent SD requires...propagation walls are used to prevent sympathetic detonation between munitions stored in adjacent cells. Design of the walls, and their mitigation...effects, requires sympathetic detonation threshold criteria for acceptor munitions. This paper outlines the procedures being used to develop SD threshold

  3. Computer simulation of the threshold sensitivity determinations

    NASA Technical Reports Server (NTRS)

    Gayle, J. B.

    1974-01-01

    A computer simulation study was carried out to evaluate various methods for determining threshold stimulus levels for impact sensitivity tests. In addition, the influence of a number of variables (initial stimulus level, particular stimulus response curve, and increment size) on the apparent threshold values and on the corresponding population response levels was determined. Finally, a critical review of previous assumptions regarding the stimulus response curve for impact testing is presented in the light of the simulation results.

  4. The odderon versus a new threshold

    SciTech Connect

    Kang, K. . Dept. of Physics); White, A.R. )

    1991-10-01

    We show that a new threshold model with a threshold close to but below the UA4 energy is compatible with all forward elastic scattering data at high energies including the widely known UA4 measurement of the forward real part of the elastic p{bar p} scattering amplitude and the recent Fermilab Tevatron Collider experiments of the p{bar p} total cross-section. 14 refs.

  5. 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.

  6. 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

  7. Optimizing Retransmission Threshold in Wireless Sensor Networks.

    PubMed

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

    2016-05-10

    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.

  8. Fibonacci thresholding: signal representation and morphological filters

    NASA Astrophysics Data System (ADS)

    Grigoryan, Artyom M.; Agaian, Sos S.

    2014-02-01

    A new weighted thresholding concept is presented, which is used for the set-theoretical representation of signals, the producing new signals containing a large number of key features that are in the original signals and the design new morphological filters. Such representation maps many operations of non binary signal and image processing to the union of the simple operations over the binary signals and images. The weighted thresholding is invariant under the morphological transformations, including the basic ones, erosion and dilation. The main idea of using the weighted thresholding is in the choice of the special level of thresholding on which we can concentrate all our attention for the future processing. Together with arithmetical thresholding the so-called Fibonacci levels are chosen because of many interesting properties; one of them is the effective decomposition of the median filter. Experimental results show that the Fibonacci thresholding is much promised and can be used for many applications, including the image enhancement, segmentation, and edge detection.

  9. 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.

  10. Electrically controllable liquid crystal random lasers below the Fréedericksz transition threshold.

    PubMed

    Lee, Chia-Rong; Lin, Jia-De; Huang, Bo-Yuang; Lin, Shih-Hung; Mo, Ting-Shan; Huang, Shuan-Yu; Kuo, Chie-Tong; Yeh, Hui-Chen

    2011-01-31

    This investigation elucidates for the first time electrically controllable random lasers below the threshold voltage in dye-doped liquid crystal (DDLC) cells with and without adding an azo-dye. Experimental results show that the lasing intensities and the energy thresholds of the random lasers can be decreased and increased, respectively, by increasing the applied voltage below the Fréedericksz transition threshold. The below-threshold-electric-controllability of the random lasers is attributable to the effective decrease of the spatial fluctuation of the orientational order and thus of the dielectric tensor of LCs by increasing the electric-field-aligned order of LCs below the threshold, thereby increasing the diffusion constant and decreasing the scattering strength of the fluorescence photons in their recurrent multiple scattering. This can result in the decrease in the lasing intensity of the random lasers and the increase in their energy thresholds. Furthermore, the addition of an azo-dye in DDLC cell can induce the range of the working voltage below the threshold for the control of the random laser to reduce.

  11. 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.

  12. Comparative study of laser damage threshold energies in the artificial retina

    NASA Astrophysics Data System (ADS)

    Payne, Dale J.; Hopkins, Richard A.; Eilert, Brent; Noojin, Gary D.; Stolarski, David J.; Thomas, Robert J.; Cain, Clarence P.; Hengst, Gordon T.; Kennedy, Paul K.; Jost, Thomas R.; Rockwell, Benjamin A.

    1999-07-01

    Laser damage threshold energies produced from ultrashort (i.e., thresholds were determined for wavelengths of 1064, 580, and 532 nm with pulse durations ranging from the nanosecond (ns) to the femtosecond (fs) regime. For the at-focus data in the visible regime, the threshold dropped from 0.25 (mu) J for a 532 nm, 5 ns pulse to 0.11 (mu) J for a 580 nm, 100 fs pulse. The near-infrared (NIR) threshold changed from 5.5 (mu) J for a 5 ns pulse to 0.9 (mu) J for a 130 fs pulse at a distance two RR in front of the focus. The experiment was repeated using the same pulse widths and wavelengths, except the water path was removed to determine the impact of nonlinear self-focusing in water. A vertical microscope imaging system was employed in order to observe the threshold event. The NIR fluence threshold of 0.5 J/cm2 remained constant within an experimental uncertainty for all pulse widths, which corresponds to values in the literature. The visible data also demonstrated a nearly constant fluence of 0.07 J/cm2. The disparity in thresholds between the two techniques arises from nonlinear optical phenomena related to propagation differences in the ocular fluid.

  13. Molecular Signaling Network Motifs Provide a Mechanistic Basis for Cellular Threshold Responses

    PubMed Central

    Bhattacharya, Sudin; Conolly, Rory B.; Clewell, Harvey J.; Kaminski, Norbert E.; Andersen, Melvin E.

    2014-01-01

    Background: Increasingly, there is a move toward using in vitro toxicity testing to assess human health risk due to chemical exposure. As with in vivo toxicity testing, an important question for in vitro results is whether there are thresholds for adverse cellular responses. Empirical evaluations may show consistency with thresholds, but the main evidence has to come from mechanistic considerations. Objectives: Cellular response behaviors depend on the molecular pathway and circuitry in the cell and the manner in which chemicals perturb these circuits. Understanding circuit structures that are inherently capable of resisting small perturbations and producing threshold responses is an important step towards mechanistically interpreting in vitro testing data. Methods: Here we have examined dose–response characteristics for several biochemical network motifs. These network motifs are basic building blocks of molecular circuits underpinning a variety of cellular functions, including adaptation, homeostasis, proliferation, differentiation, and apoptosis. For each motif, we present biological examples and models to illustrate how thresholds arise from specific network structures. Discussion and Conclusion: Integral feedback, feedforward, and transcritical bifurcation motifs can generate thresholds. Other motifs (e.g., proportional feedback and ultrasensitivity)produce responses where the slope in the low-dose region is small and stays close to the baseline. Feedforward control may lead to nonmonotonic or hormetic responses. We conclude that network motifs provide a basis for understanding thresholds for cellular responses. Computational pathway modeling of these motifs and their combinations occurring in molecular signaling networks will be a key element in new risk assessment approaches based on in vitro cellular assays. Citation: Zhang Q, Bhattacharya S, Conolly RB, Clewell HJ III, Kaminski NE, Andersen ME. 2014. Molecular signaling network motifs provide a

  14. Sexual Conflict Arising from Extrapair Matings in Birds

    PubMed Central

    Chaine, Alexis S.; Montgomerie, Robert; Lyon, Bruce E.

    2015-01-01

    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

  15. Increment Threshold Functions in Retinopathy of Prematurity

    PubMed Central

    Hansen, Ronald M.; Moskowitz, Anne; Bush, Jennifer N.; Fulton, Anne B.

    2016-01-01

    Purpose To assess scotopic background adaptation in subjects with a history of preterm birth and retinopathy of prematurity (ROP). Retinopathy of prematurity is known to have long-term effects on rod photoreceptor and rod mediated postreceptor retinal function. Methods Rod-mediated thresholds for detection of 3° diameter, 50 ms stimuli presented 20° from fixation were measured using a spatial forced choice method in 36 subjects (aged 9–17 years) with a history of preterm birth and 11 age similar term-born subjects. Thresholds were measured first in the dark-adapted condition and then in the presence of 6 steady background lights (−2.8 to +2.0 log scot td). A model of the increment threshold function was fit to each subject's thresholds to estimate the dark-adapted threshold (TDA) and the Eigengrau (A0, the background that elevates threshold 0.3 log unit above TDA). Results In subjects with a history of severe ROP, both TDA and A0 were significantly elevated relative to those in former preterms who never had ROP and term-born control subjects. Subjects who had mild ROP had normal TDA but elevated A0. Neither TDA nor A0 differed significantly between former preterms who never had ROP and term-born controls. Conclusions The results suggest that in severe ROP, threshold is affected at a preadaptation site, possibly the rod outer segment. In mild ROP, changes in the Eigengrau may reflect increased intrinsic noise in the photoreceptor or postreceptor circuitry or both. PMID:27145476

  16. Evolutionary geomorphology: thresholds and nonlinearity in landform response to environmental change

    NASA Astrophysics Data System (ADS)

    Phillips, J. D.

    2006-10-01

    Geomorphic systems are typically nonlinear, owing largely to their threshold-dominated nature (but due to other factors as well). Nonlinear geomorphic systems may exhibit complex behaviors not possible in linear systems, including dynamical instability and deterministic chaos. The latter are common in geomorphology, indicating that small, short-lived changes may produce disproportionately large and long-lived results; that evidence of geomorphic change may not reflect proportionally large external forcings; and that geomorphic systems may have multiple potential response trajectories or modes of adjustment to change. Instability and chaos do not preclude predictability, but do modify the context of predictability. The presence of chaotic dynamics inhibits or excludes some forms of predicability and prediction techniques, but does not preclude, and enables, others. These dynamics also make spatial and historical contingency inevitable: geography and history matter. Geomorphic systems are thus governed by a combination of "global" laws, generalizations and relationships that are largely (if not wholly) independent of time and place, and "local" place and/or time-contingent factors. The more factors incorporated in the representation of any geomorphic system, the more singular the results or description are. Generalization is enhanced by reducing rather than increasing the number of factors considered. Prediction of geomorphic responses calls for a recursive approach whereby global laws and local contingencies are used to constrain each other. More specifically a methodology whereby local details are embedded within simple but more highly general phenomenological models is advocated. As landscapes and landforms change in response to climate and other forcings, it cannot be assumed that geomorphic systems progress along any particular pathway. Geomorphic systems are evolutionary in the sense of being path dependent, and historically and geographically contingent

  17. Evolutionary geomorphology: thresholds and nonlinearity in landform response to environmental change

    NASA Astrophysics Data System (ADS)

    Phillips, J. D.

    2006-04-01

    Geomorphic systems are typically nonlinear, owing largely to their threshold-dominated nature (but due to other factors as well). Nonlinear geomorphic systems may exhibit complex behaviors not possible in linear systems, including dynamical instability and deterministic chaos. The latter are common in geomorphology, indicating that small, short-lived changes may produce disproportionately large and long-lived results; that evidence of geomorphic change may not reflect proportionally large external forcings; and that geomorphic systems may have multiple potential response trajectories or modes of adjustment to change. Instability and chaos do not preclude predictability, but do modify the context of predictability. The presence of chaotic dynamics inhibits or excludes some forms of predicability and prediction techniques, but does not preclude, and enables, others. These dynamics also make spatial and historical contingency inevitable: geography and history matter. Geomorphic systems are thus governed by a combination of ''global'' laws, generalizations and relationships that are largely (if not wholly) independent of time and place, and ''local'' place and/or time-contingent factors. The more factors incorporated in the representation of any geomorphic system, the more singular the results or description are. Generalization is enhanced by reducing rather than increasing the number of factors considered. Prediction of geomorphic responses calls for a recursive approach whereby global laws and local contingencies are used to constrain each other. More specifically a methodology whereby local details are embedded within simple but more highly general phenomenological models is advocated. As landscapes and landforms change in response to climate and other forcings, it cannot be assumed that geomorphic systems progress along any particular pathway. Geomorphic systems are evolutionary in the sense of being path dependent, and historically and geographically contingent

  18. Criteria and Thresholds for U.S. Navy Acoustic and Explosive Effects Analysis

    DTIC Science & Technology

    2012-04-01

    Onset, growth, and recovery of in-air temporary threshold shift in a California sea lion ( Zalophus californianus ),” Journal of the Acoustical...audiograms of several California sea lions ( Zalophus californianus ) and Steller sea lions (Eumetopias jubatus) measured using single and multiple...2011b). “California sea lion ( Zalophus californianus ) aerial hearing sensitivity measured using auditory steady-state response and psychophysical

  19. 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.

  20. 75 FR 58407 - Medicare Program; Medicare Appeals; Adjustment to the Amount in Controversy Threshold Amounts for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-24

    ... to the Amount in Controversy Threshold Amounts for Calendar Year 2011 AGENCY: Centers for Medicare... July of the preceding year involved and rounded to the nearest multiple of $10. B. Calendar Year 2011... judicial review will rise to $1,300 for the 2011 calendar year. These updated amounts are based on the...

  1. Threshold-Based OSIC Detection Algorithm for Per-Antenna-Coded TIMO-OFDM Systems

    NASA Astrophysics Data System (ADS)

    Wang, Xinzheng; Chen, Ming; Zhu, Pengcheng

    Threshold-based ordered successive interference cancellation (OSIC) detection algorithm is proposed for per-antenna-coded (PAC) two-input multiple-output (TIMO) orthogonal frequency division multiplexing (OFDM) systems. Successive interference cancellation (SIC) is performed selectively according to channel conditions. Compared with the conventional OSIC algorithm, the proposed algorithm reduces the complexity significantly with only a slight performance degradation.

  2. 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.

  3. Upper threshold of extracellular neural stimulation

    PubMed Central

    Pangratz-Fuehrer, Susanne; Suh, Bongsoo; Mathieson, Keith; Naik, Natasha; Palanker, Daniel

    2012-01-01

    It is well known that spiking neurons can produce action potentials in response to extracellular stimulation above certain threshold. It is widely assumed that there is no upper limit to somatic stimulation, except for cellular or electrode damage. Here we demonstrate that there is an upper stimulation threshold, above which no action potential can be elicited, and it is below the threshold of cellular damage. Existence of this upper stimulation threshold was confirmed in retinal ganglion cells (RGCs) at pulse durations ranging from 5 to 500 μs. The ratio of the upper to lower stimulation thresholds varied typically from 1.7 to 7.6, depending on pulse duration. Computational modeling of extracellular RGC stimulation explained the upper limit by sodium current reversal on the depolarized side of the cell membrane. This was further confirmed by experiments in the medium with a low concentration of sodium. The limited width of the stimulation window may have important implications in design of the electro-neural interfaces, including neural prosthetics. PMID:22993266

  4. Upper threshold of extracellular neural stimulation.

    PubMed

    Boinagrov, David; Pangratz-Fuehrer, Susanne; Suh, Bongsoo; Mathieson, Keith; Naik, Natasha; Palanker, Daniel

    2012-12-01

    It is well known that spiking neurons can produce action potentials in response to extracellular stimulation above certain threshold. It is widely assumed that there is no upper limit to somatic stimulation, except for cellular or electrode damage. Here we demonstrate that there is an upper stimulation threshold, above which no action potential can be elicited, and it is below the threshold of cellular damage. Existence of this upper stimulation threshold was confirmed in retinal ganglion cells (RGCs) at pulse durations ranging from 5 to 500 μs. The ratio of the upper to lower stimulation thresholds varied typically from 1.7 to 7.6, depending on pulse duration. Computational modeling of extracellular RGC stimulation explained the upper limit by sodium current reversal on the depolarized side of the cell membrane. This was further confirmed by experiments in the medium with a low concentration of sodium. The limited width of the stimulation window may have important implications in design of the electro-neural interfaces, including neural prosthetics.

  5. Threshold concepts in finance: student perspectives

    NASA Astrophysics Data System (ADS)

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

    2015-10-01

    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 finance academics. In addition, we investigate the potential of a framework of different types of knowledge to differentiate the delivery of the finance curriculum and the role of modelling in finance. Our purpose is to identify ways to improve curriculum design and delivery, leading to better student outcomes. Whilst we find that there is significant overlap between what students identify as important in finance and the threshold concepts identified by academics, much of this overlap is expressed by indirect reference to the concepts. Further, whilst different types of knowledge are apparent in the student data, there is evidence that students do not necessarily distinguish conceptual from other types of knowledge. As well as investigating the finance curriculum, the research demonstrates the use of threshold concepts to compare and contrast student and academic perceptions of a discipline and, as such, is of interest to researchers in education and other disciplines.

  6. Manganese toxicity thresholds for restoration grass species.

    PubMed

    Paschke, Mark W; Valdecantos, Alejandro; Redente, Edward F

    2005-05-01

    Manganese toxicity thresholds for restoration plants have not been established. As a result, ecological risk assessments rely on toxicity thresholds for agronomic species, which may differ from those of restoration species. Our objective was to provide Mn toxicity thresholds for grasses commonly used in restoration. We used a greenhouse screening study where seedlings of redtop, slender wheatgrass, tufted hairgrass, big bluegrass, basin wildrye, and common wheat were grown in sand culture and exposed to increasing concentrations of Mn. The LC50, EC50-plant, EC50-shoot, EC50-root, PT50-shoot, and the PT50-root were then determined. Phytotoxicity thresholds and effective concentrations for the restoration species were generally higher than values reported for agronomic species. Our estimates of PT50-shoot for the five restoration grasses range from 41,528 to 120,082 mg Mn kg(-1). Measures of EC50-plant for these restoration grasses ranged from 877 to >6,000 mg Mn l(-1). These thresholds might be more useful for risk assessors than those based on crop plants that are widely used.

  7. Threshold pion photoproduction and chiral symmetry

    SciTech Connect

    Bernstein, A.M.; Guillian, E.

    1992-12-01

    Experiments on the {gamma}p{yields}{pi}{sup o}p threshold reaction (performed at Saclay and Mainz) have attracted considerable attention because they test low energy, QCD related, predictions. The latest analyses of these data have indicated that the threshold value for the (s wave) electric dipole amplitude (E{sub o+}) is in agreement with {open_quotes}low energy theorems{close_quotes} based on current algebra (PCAC). However there was a strong energy dependence for this amplitude which makes it problematical to compare theory and experiment at only one point, the x{sup o} threshold. All of the previous analyses made model dependent assumptions about the p wave multipoles. The authors have performed, for the first time, a model independent analysis of the total and differential cross section data. In agreement with their previous analysis, and with the PCAC prediction, they obtain a threshold value of E{sub o+}= (2.0 {plus_minus} 0.2) x 10{sup {minus}3}/m{sub {pi}}. However the slope of this amplitude does not vary rapidly with energy which makes the question of what energy to compare the threshold values with theory less of a problem. A comparison with theory and previous analyses will be presented.

  8. 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.

  9. Competitive exclusion by autologous antibodies can prevent broad HIV-1 antibodies from arising

    DOE PAGES

    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

  10. Neurodevelopmental and neuropsychiatric behaviour defects arise from 14-3-3ζ deficiency.

    PubMed

    Cheah, P S; Ramshaw, H S; Thomas, P Q; Toyo-Oka, K; Xu, X; Martin, S; Coyle, P; Guthridge, M A; Stomski, F; van den Buuse, M; Wynshaw-Boris, A; Lopez, A F; Schwarz, Q P

    2012-04-01

    Complex neuropsychiatric disorders are believed to arise from multiple synergistic deficiencies within connected biological networks controlling neuronal migration, axonal pathfinding and synapse formation. Here, we show that deletion of 14-3-3ζ causes neurodevelopmental anomalies similar to those seen in neuropsychiatric disorders such as schizophrenia, autism spectrum disorder and bipolar disorder. 14-3-3ζ-deficient mice displayed striking behavioural and cognitive deficiencies including a reduced capacity to learn and remember, hyperactivity and disrupted sensorimotor gating. These deficits are accompanied by subtle developmental abnormalities of the hippocampus that are underpinned by aberrant neuronal migration. Significantly, 14-3-3ζ-deficient mice exhibited abnormal mossy fibre navigation and glutamatergic synapse formation. The molecular basis of these defects involves the schizophrenia risk factor, DISC1, which interacts isoform specifically with 14-3-3ζ. Our data provide the first evidence of a direct role for 14-3-3ζ deficiency in the aetiology of neurodevelopmental disorders and identifies 14-3-3ζ as a central risk factor in the schizophrenia protein interaction network.

  11. Ruptured saccular aneurysm arising from fenestrated proximal anterior cerebral artery : case report and literature review.

    PubMed

    Kwon, Woo-Keun; Park, Kyung-Jae; Park, Dong-Hyuk; Kang, Shin-Hyuk

    2013-05-01

    The aneurysm arising from fenestrated proximal anterior cerebral artery (ACA) is considered to be unique. The authors report a case of a 59-year-old woman who presented with a subarachnoid hemorrhage (SAH) secondary to a ruptured aneurysm originating from the fenestrated A1 segment of right ACA. The patient had another unruptured aneurysm which was located at the right middle cerebral artery bifurcation. She was successfully treated with surgical clipping for both aneurysms. From the previously existing literatures, we found 18 more cases (1983-2011) of aneurysms associated with fenestrated A1 segment. All cases represented saccular type of aneurysms, and 79% of the patients had SAH. There were three subtypes of the fenestrated A1 aneurysms depending on the anatomical location, relative to the fenestrated segment. The most common type was the aneurysms located on the proximal end of fenestrated artery (82%). Azygos ACA and hypoplastic A1 were frequently accompanied by the aneurysm (33% and 31%, respectively), and multiple aneurysms were shown in three cases (16%). Considering that fenestrated A1 segment is likely to develop an aneurysm, which has high risk of rupture, early management may benefit patients with aneurysms accompanied by fenestrated proximal ACA.

  12. Successful Chemoradiotherapy for Undifferentiated Malignant Neoplasm Arising from the Left Pulmonary Artery

    PubMed Central

    Kumagai, Hozumi; Nio, Kenta; Okumura, Yuta; Komoda, Masato; Shirakawa, Tsuyoshi; Kusaba, Hitoshi; Yasuda, Shioto; Odashiro, Keita; Arita, Shuji; Ariyama, Hiroshi; Yamada, Yuichi; Yamamoto, Hidetaka; Oda, Yoshinao; Nakamura, Katsumasa; Akashi, Koichi; Baba, Eishi

    2014-01-01

    Undifferentiated malignant neoplasms, which occur primarily in the pulmonary artery, are extremely rare and associated with poor outcomes as there is no effective therapy. A 67-year-old woman visited our hospital with complaints of dry cough and dyspnea on exertion. A contrast-enhanced chest computed tomography revealed an intravascular tumor obstructing the left pulmonary artery and a pedunculated lesion extending to the main and right pulmonary artery. Multiple metastases in the lung, bones and bilateral adrenal glands were identified by fluorodeoxyglucose-positron emission tomography. A small sample was obtained by catheter aspiration biopsy of the intravascular tumor, and examination revealed undifferentiated small atypical cells. The tumor was diagnosed as an undifferentiated neoplasm arising from the pulmonary artery based on immunohistochemical findings, including the absence of expressions of organ-specific markers. Systemic chemotherapy (paclitaxel and carboplatin) and concurrent radiation were performed as treatment for the primary tumor. Marked shrinkage of the intravascular tumor was achieved, and no serious adverse events were observed during therapy. Chemotherapy was continued for 5 months, but the patient died because of tumor progression 9 months after the initial diagnosis. Chemoradiotherapy has efficacy against undifferentiated neoplasm of the pulmonary artery. PMID:25202263

  13. 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.

  14. 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.

  15. Detection of tactile stimuli. Thresholds of afferent units related to psychophysical thresholds in the human hand.

    PubMed Central

    Johansson, R S; Vallbo, A B

    1979-01-01

    1. Psychophysical thresholds were determined at 162 points in the glabrous skin area of the human hand when slowly rising, triangular indentations of controlled amplitudes were delivered with a small probe. The method of constant stimuli was used with either the two alternative forced choice or the yes-no procedure. It was found that the distribution of the psychophysical thresholds varied with the skin region. Thresholds from the volar aspect of the fingers and the peripheral parts of the palm were low and their distribution was unimodal with a median of 11.2 micrometers. In contrast, there was an over-representation of high thresholds when observations from the centre of the palm, the lateral aspects of the fingers and the regions of the creases were pooled, and the distribution was slightly bimodal with a median of 36.0 micrometers. 2. Nerve impulses were recorded from single fibres in the median nerve of human subjects with percutaneously inserted tungsten needle electrodes. The thresholds of 128 mechanosensitive afferent units in the glabrous skin area of the hand were determined when stimuli were delivered to partly the same points as stimulated for the assessment of the psychophysical thresholds. Of the four types of units present in this area the Pacinian corpuscle (PC) and rapidly adapting (RA) units had the lowest thresholds with medians of 9.2 and 13.8 micrometers, followed by the slowly adapting type I and slowly adapting type II units with medians of 56.5 and 33.1 micrometers. There was no indication of a difference between thresholds of units located in different skin areas. 3. In the region of low psychophysical thresholds there was good agreement between the thresholds of the rapidly adapting and Pacinian corpuscle units and the psychophysical thresholds, particularly at the lower ends of the samples. In the skin regions of high thresholds, on the other hand, practically all psychophysical thresholds were higher than the thresholds of the most

  16. 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

  17. 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.

  18. 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...

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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.

  4. Near-threshold production of heavy quarks with QQbar_threshold

    NASA Astrophysics Data System (ADS)

    Beneke, M.; Kiyo, Y.; Maier, A.; Piclum, J.

    2016-12-01

    We describe the QQbar_threshold library for computing the production cross section of heavy quark-antiquark pairs near threshold at electron-positron colliders. The prediction includes all presently known QCD, electroweak, Higgs, and nonresonant corrections in the combined nonrelativistic and weak-coupling expansion.

  5. 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.

  6. Multiple Sclerosis

    MedlinePlus

    Multiple sclerosis Overview By Mayo Clinic Staff Multiple sclerosis (MS) is a potentially disabling disease of the brain and spinal cord (central nervous system). In MS, the immune system attacks the protective ...

  7. 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 ...

  8. 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 ...

  9. 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.

  10. Thresholds in Xeric Hydrology and Biogeochemistry

    NASA Astrophysics Data System (ADS)

    Meixner, T.; Brooks, P. D.; Simpson, S. C.; Soto, C. D.; Yuan, F.; Turner, D.; Richter, H.

    2011-12-01

    Due to water limitation, thresholds in hydrologic and biogeochemical processes are common in arid and semi-arid systems. Some of these thresholds such as those focused on rainfall runoff relationships have been well studied. However to gain a full picture of the role that thresholds play in driving the hydrology and biogeochemistry of xeric systems a full view of the entire array of processes at work is needed. Here a walk through the landscape of xeric systems will be conducted illustrating the powerful role of hydrologic thresholds on xeric system biogeochemistry. To understand xeric hydro-biogeochemistry two key ideas need to be focused on. First, it is important to start from a framework of reaction and transport. Second an understanding of the temporal and spatial components of thresholds that have a large impact on hydrologic and biogeochemical fluxes needs to be offered. In the uplands themselves episodic rewetting and drying of soils permits accelerated biogeochemical processing but also more gradual drainage of water through the subsurface than expected in simple conceptions of biogeochemical processes. Hydrologic thresholds (water content above hygroscopic) results in a stop start nutrient spiral of material across the landscape since runoff connecting uplands to xeric perennial riparian is episodic and often only transports materials a short distance (100's of m). This episodic movement results in important and counter-intuitive nutrient inputs to riparian zones but also significant processing and uptake of nutrients. The floods that transport these biogeochemicals also result in significant input to riparian groundwater and may be key to sustaining these critical ecosystems. Importantly the flood driven recharge process itself is a threshold process dependent on flood characteristics (floods greater than 100 cubic meters per second) and antecedent conditions (losing to near neutral gradients). Floods also appear to influence where arid and semi

  11. A dual-threshold radar detection system

    NASA Astrophysics Data System (ADS)

    Hammerle, K. J.

    It is known that the beam agility of a phased-array radar can be utilized to enhance target detection capability as compared to a radar which has the same power but which radiates its energy uniformly over the solid angle being surveilled. A dual-threshold approach for realizing this enhancement is examined. Quantitative results are presented parametrically for four signal fluctuation models. The study also identifies the optimum combination of dual-threshold design parameters for each target model under a wide range of imposed system constraints such as the allowed number of false alarms per beam position. It is shown that under certain imposed constraints, no enhancement is possible.

  12. 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.

  13. Antiboding and bonding lasing modes with low gain threshold in nonlocal metallic nanoshell.

    PubMed

    Huang, Y; Xiao, J J; Gao, L

    2015-04-06

    Based on a full-wave nonlocal Mie theory, we establish the spaser generation condition for compact plasmonic nanolasers in the long-wavelength limit for dielectric-metal core-shell nanoparticles. We found that there exist two lasing states arising from the hybridized antibonding and bonding modes for this coated nanolaser. By varying the surrounding medium and the gain materials, we can achieve low gain threshold for each mode with flexible radii ratios on the purpose of realistic easy fabrication. Numerical results show that nonlocal effects have different influences on the required gain threshold and gain refractive index of these two lasing modes, which may be of great importance in the design of such kind of ultrasmall nanoparticle lasers.

  14. 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

  15. Empirical estimation of genome-wide significance thresholds based on the 1000 Genomes Project data set

    PubMed Central

    Kanai, Masahiro; Tanaka, Toshihiro; Okada, Yukinori

    2016-01-01

    To assess the statistical significance of associations between variants and traits, genome-wide association studies (GWAS) should employ an appropriate threshold that accounts for the massive burden of multiple testing in the study. Although most studies in the current literature commonly set a genome-wide significance threshold at the level of P=5.0 × 10−8, the adequacy of this value for respective populations has not been fully investigated. To empirically estimate thresholds for different ancestral populations, we conducted GWAS simulations using the 1000 Genomes Phase 3 data set for Africans (AFR), Europeans (EUR), Admixed Americans (AMR), East Asians (EAS) and South Asians (SAS). The estimated empirical genome-wide significance thresholds were Psig=3.24 × 10−8 (AFR), 9.26 × 10−8 (EUR), 1.83 × 10−7 (AMR), 1.61 × 10−7 (EAS) and 9.46 × 10−8 (SAS). We additionally conducted trans-ethnic meta-analyses across all populations (ALL) and all populations except for AFR (ΔAFR), which yielded Psig=3.25 × 10−8 (ALL) and 4.20 × 10−8 (ΔAFR). Our results indicate that the current threshold (P=5.0 × 10−8) is overly stringent for all ancestral populations except for Africans; however, we should employ a more stringent threshold when conducting a meta-analysis, regardless of the presence of African samples. PMID:27305981

  16. Empirical estimation of genome-wide significance thresholds based on the 1000 Genomes Project data set.

    PubMed

    Kanai, Masahiro; Tanaka, Toshihiro; Okada, Yukinori

    2016-10-01

    To assess the statistical significance of associations between variants and traits, genome-wide association studies (GWAS) should employ an appropriate threshold that accounts for the massive burden of multiple testing in the study. Although most studies in the current literature commonly set a genome-wide significance threshold at the level of P=5.0 × 10(-8), the adequacy of this value for respective populations has not been fully investigated. To empirically estimate thresholds for different ancestral populations, we conducted GWAS simulations using the 1000 Genomes Phase 3 data set for Africans (AFR), Europeans (EUR), Admixed Americans (AMR), East Asians (EAS) and South Asians (SAS). The estimated empirical genome-wide significance thresholds were Psig=3.24 × 10(-8) (AFR), 9.26 × 10(-8) (EUR), 1.83 × 10(-7) (AMR), 1.61 × 10(-7) (EAS) and 9.46 × 10(-8) (SAS). We additionally conducted trans-ethnic meta-analyses across all populations (ALL) and all populations except for AFR (ΔAFR), which yielded Psig=3.25 × 10(-8) (ALL) and 4.20 × 10(-8) (ΔAFR). Our results indicate that the current threshold (P=5.0 × 10(-8)) is overly stringent for all ancestral populations except for Africans; however, we should employ a more stringent threshold when conducting a meta-analysis, regardless of the presence of African samples.

  17. 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.

  18. Glory and thresholds effects in H+D 2 reactive angular scattering

    NASA Astrophysics Data System (ADS)

    Sokolovski, D.

    2003-03-01

    We analyse H+D 2 reactive angular scattering using the S-matrix elements obtained by Aoiz et al. and Althorpe et al. Enhancement of small angle scattering in the v'=3← v=0 H+D 2 delayed reaction is attributed to a glory effect caused by threshold resonances in the v=3 vibrationally adiabatic channel. The oscillatory structures in the reactive angular distributions are shown to be of nearside-farside (NP) origin and are likely to arise from capture in a number of relatively short-lived barrier Regge states at large angular momenta. Padé reconstruction of the reactive matrix element is discussed in detail.

  19. Spin-lasers: From threshold reduction to large-signal analysis

    SciTech Connect

    Lee, Jeongsu; Bearden, Sean; Wasner, Evan; Žutić, Igor

    2014-07-28

    Lasers in which spin-polarized carriers are injected provide paths to different practical room temperature spintronic devices, not limited to magnetoresistive effects. Unlike the conventional understanding of spintronic devices, an optimal performance of such spin-lasers can arise for finite, not infinite, spin relaxation time. By considering spin-relaxation times of both electrons and holes, we elucidate advantages of spin-lasers over their conventional (spin-unpolarized) counterparts. In addition to the steady-state threshold reduction, spin-lasers can improve transient operation leading to shorter turn-on delay times, reduced ringing of emitted light, and an enhanced bandwidth.

  20. Critical thresholds in flocking hydrodynamics with non-local alignment.

    PubMed

    Tadmor, Eitan; Tan, Changhui

    2014-11-13

    We study the large-time behaviour of Eulerian systems augmented with non-local alignment. Such systems arise as hydrodynamic descriptions of agent-based models for self-organized dynamics, e.g. Cucker & Smale (2007 IEEE Trans. Autom. Control 52, 852-862. (doi:10.1109/TAC.2007.895842)) and Motsch & Tadmor (2011 J. Stat. Phys. 144, 923-947. (doi:10.1007/s10955-011-0285-9)) models. We prove that, in analogy with the agent-based models, the presence of non-local alignment enforces strong solutions to self-organize into a macroscopic flock. This then raises the question of existence of such strong solutions. We address this question in one- and two-dimensional set-ups, proving global regularity for subcritical initial data. Indeed, we show that there exist critical thresholds in the phase space of the initial configuration which dictate the global regularity versus a finite-time blow-up. In particular, we explore the regularity of non-local alignment in the presence of vacuum.

  1. Thermal pulse damage thresholds in cadmium telluride.

    PubMed

    Slattery, J E; Thompson, J S; Schroeder, J B

    1975-09-01

    A model is presented for predicting the temperature rise in an opaque material during the absorption of a moderately short pulse of energy. Experimental verification of the model employing a pulsed ruby laser and a cadmium telluride plate is described. Two distinct damage thresholds were noted: (1) at modest energy levels plastic deformation occurred, and (2) the higher energies resulted in surface melting.

  2. 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…

  3. 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....

  4. 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....

  5. 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....

  6. 40 CFR 98.441 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... amount of CO2 for long-term containment in subsurface geologic formations. There is no threshold. (b... permitted as Class VI under the Underground Injection Control program, a copy of the applicable Underground Injection Control program Director's authorization of site closure. (ii) For all other wells, and as...

  7. 40 CFR 98.441 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... amount of CO2 for long-term containment in subsurface geologic formations. There is no threshold. (b... permitted as Class VI under the Underground Injection Control program, a copy of the applicable Underground Injection Control program Director's authorization of site closure. (ii) For all other wells, and as...

  8. 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...; or, if the State had affirmatively set the cap at a lower level consistent with flexibility...

  9. 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.

  10. 40 CFR 98.351 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.351 Reporting threshold. You must... (2). (3) The facility operates an anaerobic process to treat industrial wastewater and/or industrial wastewater treatment sludge. (b) Ethanol production and food processing facilities. (1) The facility...

  11. 40 CFR 98.351 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.351 Reporting threshold. You must... (2). (3) The facility operates an anaerobic process to treat industrial wastewater and/or industrial wastewater treatment sludge. (b) Ethanol production and food processing facilities. (1) The facility...

  12. 40 CFR 98.351 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.351 Reporting threshold. You must... (2). (3) The facility operates an anaerobic process to treat industrial wastewater and/or industrial wastewater treatment sludge. (b) Ethanol production and food processing facilities. (1) The facility...

  13. 40 CFR 98.351 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment § 98.351 Reporting threshold. You must... (2). (3) The facility operates an anaerobic process to treat industrial wastewater and/or industrial wastewater treatment sludge. (b) Ethanol production and food processing facilities. (1) The facility...

  14. 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...

  15. Threshold π- production on the deuteron

    NASA Astrophysics Data System (ADS)

    Strandberg, B.; Annand, J. R. M.; Briscoe, W.; Feldman, G.; Fissum, K.; Hansen, K.; Isaksson, L.; Myers, L.; O'Reilly, G. V.

    2016-11-01

    An experiment that aims to measure the π- photoproduction cross-section σ(E) on the deuteron γ + 2H → π- + 2p near threshold is discussed. The main concepts of the experimental technique are presented alongside some preliminary signals.

  16. Simulated Critical Differences for Speech Reception Thresholds

    ERIC Educational Resources Information Center

    Pedersen, Ellen Raben; Juhl, Peter Møller

    2017-01-01

    Purpose: Critical differences state by how much 2 test results have to differ in order to be significantly different. Critical differences for discrimination scores have been available for several decades, but they do not exist for speech reception thresholds (SRTs). This study presents and discusses how critical differences for SRTs can be…

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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…

  2. 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.

  3. 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…

  4. Retinal injury thresholds for blue wavelength lasers.

    PubMed

    Lund, David J; Stuck, Bruce E; Edsall, Peter

    2006-05-01

    The interaction mechanism leading to laser-induced retinal alteration can be thermal or non-thermal, depending upon the wavelength of the laser radiation and the duration of the exposure. To investigate the effect of exposure duration on the interaction mechanism, retinal injury thresholds in the rhesus monkey were experimentally measured for exposure to laser radiation at wavelengths of 441.6, 457.9, 476.5, and 496.5 nm. Exposure durations were 0.1, 1, 5, 16, and 100 s; and 1/e retinal irradiance diameters were 50, 125, and 327 microm. Tissue response was observed via ophthalmoscope 1 h and 48 h post exposure. Thermal and non-thermal damage thresholds were obtained depending upon the exposure duration. These threshold data are in agreement with data previously reported in the literature for 100-s duration exposures, but differences were noted for shorter exposures. The current study yielded an estimated injury threshold for 1-s duration, 327-microm retinal irradiance diameter exposures at 441.6 nm, which is an order of magnitude higher than that previously reported. This study provides evidence that laser-induced retinal damage is primarily induced via thermal mechanisms for exposures shorter than 5 s in duration. Arguments are presented that support an amendment of the thermal hazard function, R(lambda).

  5. 40 CFR 98.441 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Geologic Sequestration of Carbon Dioxide § 98.441 Reporting threshold. (a... permitted as Class VI under the Underground Injection Control program, a copy of the applicable Underground Injection Control program Director's authorization of site closure. (ii) For all other wells, and as...

  6. 40 CFR 98.441 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Geologic Sequestration of Carbon Dioxide § 98.441 Reporting threshold. (a... permitted as Class VI under the Underground Injection Control program, a copy of the applicable Underground Injection Control program Director's authorization of site closure. (ii) For all other wells, and as...

  7. 40 CFR 98.301 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electrical Transmission and Distribution Equipment Use § 98.301 Reporting threshold. (a) You must report GHG emissions from an electric power system if the total nameplate capacity...). (b) A facility other than an electric power system that is subject to this part because of...

  8. Efficient adaptive thresholding with image masks

    NASA Astrophysics Data System (ADS)

    Oh, Young-Taek; Hwang, Youngkyoo; Kim, Jung-Bae; Bang, Won-Chul

    2014-03-01

    Adaptive thresholding is a useful technique for document analysis. In medical image processing, it is also helpful for segmenting structures, such as diaphragms or blood vessels. This technique sets a threshold using local information around a pixel, then binarizes the pixel according to the value. Although this technique is robust to changes in illumination, it takes a significant amount of time to compute thresholds because it requires adding all of the neighboring pixels. Integral images can alleviate this overhead; however, medical images, such as ultrasound, often come with image masks, and ordinary algorithms often cause artifacts. The main problem is that the shape of the summing area is not rectangular near the boundaries of the image mask. For example, the threshold at the boundary of the mask is incorrect because pixels on the mask image are also counted. Our key idea to cope with this problem is computing the integral image for the image mask to count the valid number of pixels. Our method is implemented on a GPU using CUDA, and experimental results show that our algorithm is 164 times faster than a naïve CPU algorithm for averaging.

  9. 40 CFR 98.91 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.91 Reporting threshold. (a) You must report GHG emissions under this subpart if electronics manufacturing production processes, as defined in.... Rather than using the calculation methodologies in § 98.93 to calculate emissions from...

  10. 40 CFR 98.91 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.91 Reporting threshold. (a) You must report GHG emissions under this subpart if electronics manufacturing production processes, as defined in.... Rather than using the calculation methodologies in § 98.93 to calculate emissions from...

  11. 40 CFR 98.91 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.91 Reporting threshold. (a) You must report GHG emissions under this subpart if electronics manufacturing production processes, as defined in.... Rather than using the calculation methodologies in § 98.93 to calculate emissions from...

  12. 40 CFR 98.91 - Reporting threshold.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Electronics Manufacturing § 98.91 Reporting threshold. (a) You must report GHG emissions under this subpart if electronics manufacturing production processes, as defined in.... Rather than using the calculation methodologies in § 98.93 to calculate emissions from...

  13. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an industrial waste landfill meeting the...)(2), the emissions from the industrial waste landfill are to be determined using the...

  14. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an industrial waste landfill meeting the...)(2), the emissions from the industrial waste landfill are to be determined using the...

  15. 40 CFR 98.461 - Reporting threshold.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Industrial Waste Landfills § 98.461 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an industrial waste landfill meeting the...)(2), the emissions from the industrial waste landfill are to be determined using the...

  16. 49 CFR 80.13 - Threshold criteria.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Intelligent Transportation Systems (ITS), eligible project costs shall be reasonably anticipated to equal or... 49 Transportation 1 2010-10-01 2010-10-01 false Threshold criteria. 80.13 Section 80.13 Transportation Office of the Secretary of Transportation CREDIT ASSISTANCE FOR SURFACE TRANSPORTATION...

  17. 49 CFR 80.13 - Threshold criteria.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Intelligent Transportation Systems (ITS), eligible project costs shall be reasonably anticipated to equal or... 49 Transportation 1 2011-10-01 2011-10-01 false Threshold criteria. 80.13 Section 80.13 Transportation Office of the Secretary of Transportation CREDIT ASSISTANCE FOR SURFACE TRANSPORTATION...

  18. 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…

  19. [Threshold values for chemicals to prevent disease].

    PubMed

    Schweinsberg, F

    1990-05-01

    Proper interpretation of threshold limit values should always take into account that such limits are not absolute, but rather subject to change depending on advances in scientific knowledge. Threshold limit values derived from toxicologic study are best suited to evaluation of health risks of chemicals in the environment. Although more toxicologic information than is currently available would be desirable for the establishment of limit values, this should not prevent agreement on limits for more substances. "Better" threshold limit values would be forthcoming from epidemiologic studies, which are particularly rare in the FRG. Prospective studies measure current exposure; but appearance of detrimental health effects generally requires a lengthy latency period (e.g., decades in the case of cancer or cardiovascular disease). Threshold limit values permit monitoring and, if necessary, restriction of anthropogenic activity. Such restrictions are necessary, as shown by severe health damage which has occurred in the past (e.g., angiosarcoma due to vinyl chloride or neurogenic damage due to mercury in the workplace, tumors due to arsenic in drinking water, and methemoglobinemia in infants due to nitrite or renal damage due to cadmium in food). Evaluation of potential detrimental health effects for threshold limit values in environmental media is difficult because the effective dose cannot be determined. Monitoring of such limit values, which have already been incorporated into West German law, is relatively easy to implement, however (e.g. continuous outdoor air quality sampling and measurement, and periodic analysis of drinking water and foodstuffs). Since such monitoring may be performed close to the source, preventive measures should be easy to implement. Biological threshold limit values (biological monitoring) are essential to effective evaluation of the health effects of chemicals. Such limits should be established for more substances. When biological limit values

  20. Measurement of ventilatory threshold by respiratory frequency.

    PubMed

    Nabetani, Teru; Ueda, Takeshi; Teramoto, Keisuke

    2002-06-01

    This study was conducted to assess whether respiratory frequency can be used as a valid parameter for estimating ventilatory threshold and for examining differences in exercise modes such as a cycle ergometer and a treadmill. 24 men and 12 women performed an incremental exercise test to exhaustion on a cycle ergometer and on a treadmill. Oxygen uptake, carbon dioxide output, pulmonary ventilation, ventilatory frequency, and heart rate were measured continuously every 30 sec. during the test. Three different and independent reviewers detected the ventilatory threshold point and break point of respiratory rate, which were then compared. Analysis indicated that (1) ventilatory threshold was well correlated with break point of respiratory rate for both cycle (r=.88, p<.001) and treadmill exercise (r=.96, p<.001). However, on the average, ventilatory threshold was only 71% (cycle) or 88% (treadmill) of break point of respiratory rate. (2) The regression equation for treadmill exercise was more accurate than that for cycling, but the detected data samples were smaller. The break point of respiratory rate was more easily detected for the cycle ergometer test 33 of 36 subjects) than for the treadmill test (only 15 of 36). The cycle ergometer test identified the break point of respiratory rate more easily than did the treadmill test. (3) There was an association between physical fitness and whether the break point of respiratory rate was detectable, and the more fit the subject (above average), the more likely the break point was to be undetected. Our study demonstrates that the break point of respiratory rate is closely associated with ventilatory threshold and that the cycle ergometer test is more conducive than the treadmill test to the detectability of break point of respiratory rate.