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Sample records for multiple thresholds arise

  1. Multiple Thresholds Arise in a Model System of Noisy Ion Channels

    CERN Document Server

    Barber, M J; Barber, Michael J.; Ristig, Manfred L.

    2006-01-01

    Voltage-activated ion channels vary randomly between a conducting or open state and a nonconducting or closed state in response to thermal fluctuations, with this variation influenced by the membrane potential and a broad assortment of other factors. We show that signal transduction is enhanced by a non-zero level of noise in a simple model of ion channels. The enhancement is restricted to a finite range of signals, but this range can be extended using populations of channels. The range increases more rapidly in heterogeneous populations of channels having various thresholds than in homogeneous populations of channels with a single threshold. The diversity of cellular ion channels may thus be present as an economical information-processing strategy, reducing the metabolic cost of handling a broad class of electrochemical signals with simple processing elements.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

  4. Multiple Ectopic Hepatocellular Carcinomas Arising in the Abdominal Cavity

    Directory of Open Access Journals (Sweden)

    Toru Miyake

    2012-09-01

    Full Text Available 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.

  5. Multiple imputation for threshold-crossing data with interval censoring.

    Science.gov (United States)

    Dorey, F J; Little, R J; Schenker, N

    1993-09-15

    Medical statistics often involve measurements of the time when a variable crosses a threshold value. The time to threshold crossing may be the outcome variable in a survival analysis, or a time-dependent covariate in the analysis of a subsequent event. This paper presents new methods for analysing threshold-crossing data that are interval censored in that the time of threshold crossing is known only within a specified interval. Such data typically arise in event-history studies when the threshold is crossed at some time between data-collection points, such as visits to a clinic. We propose methods based on multiple imputation of the threshold-crossing time with use of models that take into account values recorded at the times of visits. We apply the methods to two real data sets, one involving hip replacements and the other on the prostate specific antigen (PSA) assay for prostate cancer. In addition, we compare our methods with the common practice of imputing the threshold-crossing time as the right endpoint of the interval. The two examples require different imputation models, but both lead to simple analyses of the multiply imputed data that automatically take into account variability due to imputation.

  6. Multiple threshold tracking methods for improved observation of nociceptive function

    NARCIS (Netherlands)

    Doll, Robert; Meijer, Hil Gaétan Ellart; Buitenweg, Jan R.

    2013-01-01

    Estimating momentary perception thresholds cannot reveal dynamic properties of underlying mechanisms. However, continuously estimating multiple thresholds can. This talk focussed on the possibility of tracking multiple thresholds over time. A cold pressor model was used to activate descending

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

    Directory of Open Access Journals (Sweden)

    Jeffrey A Anderson

    Full Text Available 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.

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

    Science.gov (United States)

    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

  9. Multiple solutions for inhomogeneous nonlinear elliptic problems arising in astrophyiscs

    Directory of Open Access Journals (Sweden)

    Marco Calahorrano

    2004-04-01

    Full Text Available Using variational methods we prove the existence and multiplicity of solutions for some nonlinear inhomogeneous elliptic problems on a bounded domain in $mathbb{R}^n$, with $ngeq 2$ and a smooth boundary, and when the domain is $mathbb{R}_+^n$

  10. Multiple benefits arising from novel management of agricultural ditches

    Science.gov (United States)

    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.

  11. Adaptive Threshold Median Filter for Multiple-Impulse Noise

    Institute of Scientific and Technical Information of China (English)

    JIANG Bo; HUANG Wei

    2007-01-01

    Attenuating the noises plays an essential role in the image processing. Almost all the traditional median filters concern the removal of impulse noise having a single layer, whose noise gray level value is constant. In this paper, a new adaptive median filter is proposed to handle those images corrupted not only by single layer noise. The adaptive threshold median filter(ATMF) has been developed by combining the adaptive median filter (AMF) and two dynamic thresholds. Because of the dynamic threshold being used, the ATMF is able to balance the removal of the multiple-impulse noise and the quality of image. Comparison of the proposed method with traditional median filters is provided. Some visual examples are given to demonstrate the performance of the proposed Filter.

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

    CERN Document Server

    Singh, P; 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 {\\it initiators} trigger the cascade, and where all nodes possess the same adoption threshold $\\phi$. 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 $\\phi$, there exists a critical initiator fraction $p_c(\\phi)$ 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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  15. Multiple simultaneous choroidal melanomas arising in the same eye: globe salvage by radiotherapy.

    Science.gov (United States)

    Zhang, Matthew M; Papakostas, Thanos D; Malcolm, Arnold W; Ancell, Kristin K; Biscotti, Charles V; Gragoudas, Evangelos S; Daniels, Anthony B

    2016-12-01

    Multiple choroidal melanomas arising in the same eye is a very rare entity, usually leading ophthalmologists to entertain other diagnoses. Historically, the only available treatment reported for this rare entity was enucleation. In this study we demonstrate in a series of patients with multiple simultaneous choroidal melanomas that eye salvage is possible using a variety of radiotherapy techniques. Both patients presented with two simultaneous choroidal melanomas in one eye. The first patient was only 30 years old and presented with two largely amelanotic tumours with large exudative retinal detachment. Cytology from fine needle aspiration biopsies from both tumours with immunohistochemistry confirmed two separate melanomas. Sequential radioactive iodine plaque brachytherapy led to regression of both tumours. The second, older patient's two tumours both had the typical appearance of choroidal melanoma and he underwent proton beam irradiation to the entire field leading to tumour regression. Multiple choroidal melanomas can rarely arise simultaneously in the same eye, and despite their variable appearance, a definitive diagnosis can be aided by cytology and immunohistochemistry in atypical-appearing cases. While all other previously reported cases have necessitated enucleation, we demonstrate that globe salvage is possible using either proton beam irradiation to the entire tumour field, or with sequential radioactive plaque brachytherapy. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  16. Orthogonal DF Cooperative Relay Networks with Multiple-SNR Thresholds and Multiple Hard-Decision Detections

    Directory of Open Access Journals (Sweden)

    Dian-Wu Yue

    2010-01-01

    Full Text Available This paper investigates a wireless cooperative relay network with multiple relays communicating with the destination over orthogonal channels. Proposed is a cooperative transmission scheme that employs two signal-to-noise ratio (SNR thresholds and multiple hard-decision detections (HDD at the destination. One SNR threshold is used to select transmitting relays, and the other threshold is used at the destination for detection. Then the destination simply combines all the hard-decision results and makes the final binary decision based on majority voting. Focusing on the decode-and-forward (DF relaying protocol, the average bit error probability is derived and diversity analysis is carried out. It is shown that the full diversity order can be achieved by setting appropriate thresholds even when the destination does not know the exact or average SNRs of the source-relay links. The performance analysis is further extended to multi-hop cooperation and/or with the presence of a direct link where multiple thresholds are needed. By combining the multiple-SNR threshold method with a selection of the best relaying link, a high spectral-efficiency cooperative transmission scheme is further presented. Simulation results verify the theoretical analysis and demonstrate performance advantage of our proposed schemes over the existing ones.

  17. CALCULUS FROM THE PAST: MULTIPLE DELAY SYSTEMS ARISING IN CANCER CELL MODELLING

    KAUST Repository

    WAKE, G. C.

    2013-01-01

    Nonlocal calculus is often overlooked in the mathematics curriculum. In this paper we present an interesting new class of nonlocal problems that arise from modelling the growth and division of cells, especially cancer cells, as they progress through the cell cycle. The cellular biomass is assumed to be unstructured in size or position, and its evolution governed by a time-dependent system of ordinary differential equations with multiple time delays. The system is linear and taken to be autonomous. As a result, it is possible to reduce its solution to that of a nonlinear matrix eigenvalue problem. This method is illustrated by considering case studies, including a model of the cell cycle developed recently by Simms, Bean and Koeber. The paper concludes by explaining how asymptotic expressions for the distribution of cells across the compartments can be determined and used to assess the impact of different chemotherapeutic agents. Copyright © 2013 Australian Mathematical Society.

  18. Multiple giant coronary aneurysms arising from coronary istula to the pulmonary artery revealed in aorta CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Eun Ju; Lee, Ki Nam [Dept. of Radiology, Dong A University Hospital, Dong-A University College of Medicine, Busan (Korea, Republic of); Lee, Jong Min [Dept. of Radiology, Kyungpook National University Hospital, Kyungpook National University College of Medicine, Daegu (Korea, Republic of)

    2015-12-15

    Coronary fistula is a rare coronary abnormality through which blood drains into the cardiac chamber, great vessel or other vessels. In addition, giant aneurysm arising from coronary fistula is rare pathologic manifestation. Herein, we presented a rare case of multiple giant coronary artery aneurysms arising from coronary to pulmonary artery fistula in a 79-year-old woman presenting with sudden loss of consciousness. The aneurysms were detected using thoracic computed tomography angiography and consequently confirmed by invasive coronary angiography.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    Karampourniotis, Panagiotis D; 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...

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

    Energy Technology Data Exchange (ETDEWEB)

    Burkart, W. [Institute of Radiation Hygiene of the Federal Office for Radiation Protection, Ingolstaedter Landstr. 1, D 85716 Oberschleissheim, Muenchen (Germany)

    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.

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

    Science.gov (United States)

    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.

  3. Adaptive Double Threshold with Multiple Energy Detection Technique in Cognitive Radio

    Directory of Open Access Journals (Sweden)

    J. Avila

    2015-08-01

    Full Text Available The Cognitive Radio (CR network is a system which lends help at the time of scarcity in spectrum. One of the process by which CR senses the spectrum is energy detection method with a fixed single threshold. When energy levels fall below the threshold, secondary user is permitted to use the spectrum of the primary user. It is shown by simulation results that having two levels of threshold i.e., double threshold improves performance by giving importance to one of the major aspects of CR, reducing the confliction of the primary and the secondary user. For enhanced performance under noise conditions, dynamic allocation or adaptive threshold is employed with the two levels of threshold. The system is made better by the use of multiple energy detectors on the reception end.

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

    Science.gov (United States)

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

    2016-02-08

    We report a rare case of a 61-year-old homeless man with a 15-year history of multiple trichilemmal cysts that served as a forerunner for the emergence of a malignant proliferating pilar tumour. The patient presented multiple, large, purulent, ulcerated lesions ranging from 10 to 150 mm in diameter, covering most of the scalp, with large areas superimposed by extensive myiasis infestation. The patient presented with no other major clinical findings. A CT scan showed no detectable signs of local or distant metastatic invasion. Initial supportive treatment was implemented. Given the extent of the injury, further surgical excision was considered, which required transfer to a specialised surgical centre. This social case is of educational value, as it can raise clinician awareness about the ability of trichilemmal cysts to undergo malignant transformation. Additionally, it highlights the importance of adequate social assistance structures for patients in need. 2016 BMJ Publishing Group Ltd.

  5. Multiplicative gain modulation arising from inhibitory synaptic plasticity in the cerebellar nuclei

    Directory of Open Access Journals (Sweden)

    Dimitris Bampasakis

    2014-03-01

    Full Text Available Neurons use the rate of action potentials to encode sensory variables. This makes the output rate as a function of input, also known as input-output (I–O relationship, a core computational function in neuronal processing. The introduction, or increase, of a modulatory input, can transform this function in multiple ways: additive transformations result in a shift, and multiplicative transformations in a change of slope of the I–O relationship. This slope change is known as gain modulation, and it can implement important forms of neural computation such as coordinate transformations. Gain modulation can be found in a wide range of brain systems, including the cerebellum, where it can be enabled by synaptic plasticity at both excitatory and inhibitory synapses. We use a realistic, conductance based, multi-compartmental model of a cerebellar nucleus (CN neuron, to investigate the determinants of gain modulation mediated by synaptic plasticity. In particular, we are interested in the effect of short term depression (STD at the inhibitory synapse from Purkinje cells (PCs to CN neurons. Considering the inhibitory PC input as the driving input, we compare the I–O relationship of the CN neuron in the presence and absence of STD for 20 Hz of excitatory synaptic input from mossy fibers (MFs, and find that STD introduces a gain change, changing the slope of the I–O function. We then proceed to compare the transformation performed by the increase of the modulatory input from 20 to 50 Hz, in the presence and absence of STD. We find that the presence of STD in the inhibitory synapse introduces a multiplicative component in the transformation performed by the excitatory input, an effect that persists for different levels of STD, and various combinations of regularity and synchronicity in the input.

  6. Familial multiple exostosis arising from bones of enchondral as well as membranous (in a family affecting seven members

    Directory of Open Access Journals (Sweden)

    Maruti Kambali

    2012-01-01

    Full Text Available Familial multiple exostosis in a family of seven members who are affected found that exostosis was arising both from bones of enchondral as well as membranous ossification, which was sessile as well as pedunculated and was larger in size at the growing ends of the bones. The lesions occur only in bones that develop from cartilage (endochondral ossification. In our study, we have noticed lesions occurring in both endochondral as well as membranous bone. Till now, no article has mentioned about membranous origin (clavicle.

  7. Neuroendocrine Cell Carcinoma of Unknown Primary Arising in Long Standing History of Multiple Sclerosis

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    Stergios Boussios

    2015-01-01

    Full Text Available Multiple sclerosis (MS is a chronic autoimmune disease that targets myelinated axons in the central nervous system (CNS. Cancer of unknown primary site (CUP is a well-recognised clinical disorder, accounting for 3–5% of all malignant epithelial tumors. CUP is clinically characterised as an aggressive disease with early dissemination. Studies of cancer risk in MS patients have shown inconsistent findings. An increased risk of malignancy in patients with MS has been suggested, but recently serious questions have been raised regarding this association. Use of disease-modifying therapies might contribute to an increased cancer risk in selected MS patients. The concurrence of MS and CUP is exceptionally rare. Here we describe the case of a neuroendocrine carcinoma of unknown primary diagnosed in a male patient with a nine-year history of MS. The discussion includes data from all available population-based register studies with estimates of certain malignancies in patients with MS.

  8. Observation of Multiple Thresholds in the Many-Atom Cavity QED Microlaser

    CERN Document Server

    Fang-Yen, C; Ha, S; Choi, W; An, K; Dasari, R R; Feld, M S

    2004-01-01

    We report the observation of multiple laser thresholds in the many-atom cavity QED microlaser. Traveling-wave coupling and a supersonic atom beam are used to create a well-defined atom-cavity interaction. Multiple thresholds are observed as jumps in photon number due to oscillatory gain. Although the number of intra-cavity atoms is large, up to N~1000, the dynamics of the microlaser agree with a single atom theory. This agreement is supported by quantum trajectory simulations of a many-atom microlaser and a semiclassical microlaser theory. We discuss the relation of the microlaser with the micromaser and conventional lasers.

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

    Science.gov (United States)

    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.

  10. The economics of the thermohaline circulation - A problem with multiple thresholds of unknown locations

    Energy Technology Data Exchange (ETDEWEB)

    Naevdal, Eric [Department of Economics, University of Oslo, P.O. Box 1095, Blindern, N-0317 Oslo (Norway); Oppenheimer, Michael [Woodrow Wilson School, Princeton University, NJ (United States); Department of Geosciences, Princeton University, NJ (United States)

    2007-11-15

    A potentially serious environmental threat facing humanity is the possibility of a collapse of the thermohaline circulation. Resulting climate changes, including absolute cooling near Greenland and northwest Europe, could be abrupt. Collapse of the thermohaline circulation may be triggered if the temperature or the rate of temperature change exceeds certain thresholds. The locations of these thresholds are unknown. Economic regulation of this problem requires solution methods for a class of dynamic optimization problems with multiple thresholds located in n-dimensional space. This class of problems has hitherto not been discussed in the literature. We present a model for the economic regulation of CO{sub 2} emissions in the presence of threshold-triggered risk of a collapsing thermohaline circulation and derive optimality conditions for regulation. (author)

  11. Estimation of detection threshold in multiple ship target situations with HF ground wave radar

    Institute of Scientific and Technical Information of China (English)

    Li Hongbo; Shen Yiying; Liu Yongtan

    2007-01-01

    A credible method of calculating the detection threshold is presented for the multiple target situations,which appear frequently in the lower Doppler velocity region during the surveillance of sea with HF ground wave radar. This method defines a whole-peak-outlier elimination (WPOE) criterion, which is based on in-peak-samples correlation of each target echo spectra, to trim off the target signals and abnormal disturbances with great amplitude from the complex spectra. Therefore, cleaned background noise samples are obtained to improve the accuracy and reliability of noise level estimation. When the background noise is nonhomogeneous, the detection samples are limited and often occupied heavily with outliers. In this case, the problem that the detection threshold is overvalued can be solved. In applications on experimental data, it is verified that this method can reduce the miss alarm rate of signal detection effectively in multiple target situations as well as make the adaptability of the detector better.

  12. Assessment of radioactive residues arising from radiolabel instability in a multiple dose tissue distribution study in rats

    Energy Technology Data Exchange (ETDEWEB)

    Slatter, J.G. [Pharmacia Corp., Peapack, NJ (United States); Sams, J.P.; Easter, J.A. [Pharmacia Corp., Kalamazoo, MI (United States)] [and others

    2003-05-01

    Our study objectives were to quantitatively determine the effect of radiolabel instability on terminal phase radioactive tissue residues in a multiple dose tissue distribution study, to quantitatively compare tissue residue artifacts (non drug-related radioactivity) from two chemically-distinct radiolabel locations, and to conduct a definitive multiple dose tissue distribution study using the better of the two radiolabeled compounds. We compared the excretion and tissue distribution in rats of [{sup 14}C]linezolid, radiolabeled in two different locations, after 7 consecutive once daily [{sup 14}C] oral doses. The radiolabels were in the acetamide (two carbon) and oxazolidinone (isolated carbon) functional groups. Terminal phase tissue residue and excretion data were compared to data from rats dosed orally with [{sup 14}C]sodium acetate. Drug-related radioactivity was excreted rapidly over 24 h. After a single dose, the acetamide and oxazolidinone radiolabel sites both gave 3% of dose as exhaled {sup 14}CO{sub 2}. After 7 daily [{sup 14}C] oral doses, terminal phase radioactive tissue residues were higher from the acetamide radiolabel, relative to the oxazolidinone radiolabel, and were primarily not drug-related. In the definitive tissue distribution study, low concentrations of drug-related radioactivity in skin and thyroid were observed. We conclude that although small amounts of radiolabel instability do not significantly affect single dose tissue radioactivity C{sub max} and area under the curve (AUC), artifacts arising from radiolabel instability can prolong the apparent terminal phase half life and complicate study data interpretation. When possible, it is always preferable to use a completely stable radiolabel site. (author)

  13. Multiple origins of spontaneously arising micronuclei in HeLa cells: Direct evidence from long-term live cell imaging

    Energy Technology Data Exchange (ETDEWEB)

    Rao Xiaotang; Zhang Yingyin; Yi Qiyi; Hou Heli; Xu Bo; Chu Liang; Huang Yun; Zhang Wenrui [Laboratory of Molecular and Cell Genetics, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 (China); Fenech, Michael [CSIRO Human Nutrition, PO Box 10041, Adelaide BC, Adelaide, SA 5000 (Australia); Shi Qinghua [Laboratory of Molecular and Cell Genetics, Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230027 (China)], E-mail: qshi@ustc.edu.cn

    2008-11-10

    Although micronuclei (MNi) are extensively used to evaluate genotoxic effects and chromosome instability, the most basic issue regarding their origins has not been completely addressed due to limitations of traditional methods. Recently, long-term live cell imaging was developed to monitor the dynamics of single cell in a real-time and high-throughput manner. In the present study, this state-of-the-art technique was employed to examine spontaneous micronucleus (MN) formation in untreated HeLa cells. We demonstrate that spontaneous MNi are derived from incorrectly aligned chromosomes in metaphase (displaced chromosomes, DCs), lagging chromosomes (LCs) and broken chromosome bridges (CBs) in later mitotic stages, but not nuclear buds in S phase. However, most of bipolar mitoses with DCs (91.29%), LCs (73.11%) and broken CBs (88.93%) did not give rise to MNi. Our data also show directly, for the first time, that MNi could originate spontaneously from (1) MNi already presented in the mother cells; (2) nuclear fragments that appeared during mitosis with CB; and (3) chromosomes being extruded into a minicell which fused with one of the daughter cells later. Quantitatively, most of MNi originated from LCs (63.66%), DCs (10.97%) and broken CBs (9.25%). Taken together, these direct evidences show that there are multiple origins for spontaneously arising MNi in HeLa cells and each mechanism contributes to overall MN formation to different extents.

  14. Increased sensitivity to supra-threshold painful stimuli in patients with multiple functional somatic symptoms (MFS)

    DEFF Research Database (Denmark)

    Kuzminskyte, Ruta; Kupers, Ronny Clement Florent; Videbech, Poul;

    2010-01-01

    -rated subjective emotional responses to the pain stressor. Contrary to the hypothesis, the pain threshold was not lower in MFS; the data even showed a trend in the opposite direction. Pain tolerance scores were identical in the two groups but they correlated negatively with the number of functional somatic......Many patients in a variety of medical settings suffer from persistently painful bodily symptoms that are not explained by known pathophysiological mechanisms. In the most severe cases, these patients complain of multiple functional somatic symptoms (MFS). We tested the hypothesis of reduced pain...... threshold and pain tolerance levels in patients with MFS. Twenty-two patients with MFS and 27 age- and sex-matched healthy control subjects volunteered for this study. The subjects received innocuous and noxious thermal stimuli to the volar forearm by means of a Peltier contact heat probe. We assessed pain...

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

    Directory of Open Access Journals (Sweden)

    Christian Thaler

    Full Text Available Magnetic Resonance Imaging (MRI is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS. While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation.We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT thresholds to achieve best possible correlation between BH lesion volume and clinical disability.40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR, magnetization-prepared rapid gradient echo (MPRAGE before and after Gadolinium (GD injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE sequences. BHs (BHvis were marked by two raters on native T1-weighted (T1w-MPRAGE, contrast-enhancing lesions (CE lesions on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite and lesion volume were determined for different T1-RT thresholds.Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p1500 ms (Expanded Disability Status Scale vs. lesion volume: rBHvis = 0.442 and rtotal-FLAIR = 0.497, p<0.05; Multiple Sclerosis Functional Composite vs. lesion volume: rBHvis = -0.53 and rtotal-FLAIR = -0.627, p<0.05.Clinical-radiological correlations in MS patients are

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

    Science.gov (United States)

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

    2015-01-01

    Magnetic Resonance Imaging (MRI) is an established tool in diagnosing and evaluating disease activity in Multiple Sclerosis (MS). While clinical-radiological correlations are limited in general, hypointense T1 lesions (also known as Black Holes (BH)) have shown some promising results. The definition of BHs is very heterogeneous and depends on subjective visual evaluation. We aimed to improve clinical-radiological correlations by defining BHs using T1 relaxation time (T1-RT) thresholds to achieve best possible correlation between BH lesion volume and clinical disability. 40 patients with mainly relapsing-remitting MS underwent MRI including 3-dimensional fluid attenuated inversion recovery (FLAIR), magnetization-prepared rapid gradient echo (MPRAGE) before and after Gadolinium (GD) injection and double inversion-contrast magnetization-prepared rapid gradient echo (MP2RAGE) sequences. BHs (BHvis) were marked by two raters on native T1-weighted (T1w)-MPRAGE, contrast-enhancing lesions (CE lesions) on T1w-MPRAGE after GD and FLAIR lesions (total-FLAIR lesions) were detected separately. BHvis and total-FLAIR lesion maps were registered to MP2RAGE images, and the mean T1-RT were calculated for all lesion ROIs. Mean T1 values of the cortex (CTX) were calculated for each patient. Subsequently, Spearman rank correlations between clinical scores (Expanded Disability Status Scale and Multiple Sclerosis Functional Composite) and lesion volume were determined for different T1-RT thresholds. Significant differences in T1-RT were obtained between all different lesion types with highest T1 values in visually marked BHs (BHvis: 1453.3±213.4 ms, total-FLAIR lesions: 1394.33±187.38 ms, CTX: 1305.6±35.8 ms; p1500 ms (Expanded Disability Status Scale vs. lesion volume: rBHvis = 0.442 and rtotal-FLAIR = 0.497, p<0.05; Multiple Sclerosis Functional Composite vs. lesion volume: rBHvis = -0.53 and rtotal-FLAIR = -0.627, p<0.05). Clinical-radiological correlations in MS patients are

  17. A threshold-based multiple optical signal selection scheme for WDM FSO systems

    KAUST Repository

    Nam, Sung Sik

    2017-07-20

    In this paper, we propose a threshold-based-multiple optical signal selection scheme (TMOS) for free-space optical systems based on wavelength division multiplexing. With the proposed TMOS, we can obtain higher spectral efficiency while reducing the potential increase in complexity of implementation caused by applying a selection-based beam selection scheme without a considerable performance loss. Here, to accurately characterize the performance of the proposed TMOS, we statistically analyze the characteristics with heterodyne detection technique over independent and identically distributed Log-normal turbulence conditions taking into considerations the impact of pointing error. Specifically, we derive exact closed-form expressions for the average bit error rate, and the average spectral efficiency by adopting an adaptive modulation. Some selected results shows that the average spectral efficiency can be increased with TMOS while the system requirement is satisfied.

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

    Science.gov (United States)

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

    2016-09-01

    Polyandry is often hypothesized to evolve to allow females to adjust the degree to which they inbreed. Multiple factors might affect such evolution, including inbreeding depression, direct costs, constraints on male availability, and the nature of polyandry as a threshold trait. Complex models are required to evaluate when evolution of polyandry to adjust inbreeding is predicted to arise. We used a genetically explicit individual-based model to track the joint evolution of inbreeding strategy and polyandry defined as a polygenic threshold trait. Evolution of polyandry to avoid inbreeding only occurred given strong inbreeding depression, low direct costs, and severe restrictions on initial versus additional male availability. Evolution of polyandry to prefer inbreeding only occurred given zero inbreeding depression and direct costs, and given similarly severe restrictions on male availability. However, due to its threshold nature, phenotypic polyandry was frequently expressed even when strongly selected against and hence maladaptive. Further, the degree to which females adjusted inbreeding through polyandry was typically very small, and often reflected constraints on male availability rather than adaptive reproductive strategy. Evolution of polyandry solely to adjust inbreeding might consequently be highly restricted in nature, and such evolution cannot necessarily be directly inferred from observed magnitudes of inbreeding adjustment. © 2016 The Author(s). Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

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

    Science.gov (United States)

    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.

  20. Analysis on the damage threshold of MgO:LiNbO3 crystals under multiple femtosecond laser pulses

    Science.gov (United States)

    Su, Zhuolin; Meng, Qinglong; Zhang, Bin

    2016-10-01

    An improved theoretical model of the interaction between multiple femtosecond laser pulses and MgO:LiNbO3 crystals with different doping concentrations has been established based on the classical two-temperature model. The evolutions of electron and lattice temperature with the duration, the repetition frequency and the numbers of multiple femtosecond laser pulses in MgO:LiNbO3 crystals have been simulated numerically by the Crank-Nicholson implicit finite-difference method. Furthermore, the variations of the damage threshold of MgO:LiNbO3 crystals with the parameters of multiple femtosecond laser pulses at different doping concentrations, as well as the influence of doping concentration on damage threshold have also been analyzed. The results show that, the damage threshold of MgO:LiNbO3 crystals increases with the increasing of the duration of the femtosecond laser pulse. The damage threshold of MgO:LiNbO3 crystals first decreases with the increasing of the numbers and the pulse repetition frequency of the laser pulses and then tends to be a constant. The damage threshold of a small amount of MgO-doped LiNbO3 crystals is higher than that of undoped LiNbO3 crystals. Consequently, the resist damage capability of LiNbO3 crystals can be enhanced by doping appropriate MgO in many practical applications.

  1. Multiple basal cell carcinomas arising in a port-wine stain with a remote history of therapeutic irradiation.

    Science.gov (United States)

    Kim, Byung-Soo; Lee, Jae-Bong; Jang, Ho-Sun; Kwon, Yoo-Wook; Kwon, Kyung-Sool; Oh, Chang-Keun

    2004-10-01

    The coexistence of a basal cell carcinoma and a port-wine stain is a very rare condition that may be associated with previous treatments. We present a case of multiple basal cell carcinomas developing within the boundaries of a port-wine stain, which had been treated with a tholium X and argon laser. Our case suggests that port-wine stains which were previously treated with irradiation or argon laser should be examined carefully and regularly by both physician and patient, because they may hide basal cell carcinomas.

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

    Science.gov (United States)

    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

  3. Multiple factors and thresholds explaining fish species distributions in lowland streams

    Directory of Open Access Journals (Sweden)

    Cristina Trigal

    2015-07-01

    Full Text Available Appropriate restoration and conservation measures require a good understanding of the factors limiting the distribution of species, the presence of steep changes in the distribution along environmental gradients and the effect of environmental interactions on species distribution. We used 12 environmental variables describing connectivity, hydrology, climate and stream morphology, to model the distributions of 17 fish species from 2005 Swedish stream sites that were sampled between 2000 and 2011. Modeling was performed using boosted regression trees and random forest, two machine learning techniques to assess the relationship between species distributions and their environment. Temperature, width and connectivity (minimum distance to lake or the sea and water discharge, were the most important variables explaining changes in species distribution at large spatial scales. Response curves of fitted occurrence probabilities along predictors often showed abrupt changes, however, clear threshold effects were difficult to detect. Our results show also differences across species and even in the outcomes of the two algorithms, implying that a simultaneous assessment of multiple species may provide a better signal of ecosystem change than the use of surrogate species.

  4. Dichotic multiple-frequency auditory steady-state responses in evaluating the hearing thresholds of occupational noise-exposed workers

    Directory of Open Access Journals (Sweden)

    Ruey-Fen Hsu

    2011-08-01

    Full Text Available An objective, fast, and reasonably accurate assessment test that allows for easy interpretation of the responses of the hearing thresholds at all frequencies of a conventional audiogram is needed to resolve the medicolegal aspects of an occupational hearing injury. This study evaluated the use of dichotic multiple-frequency auditory steady-state responses (Mf-ASSR to predict the hearing thresholds in workers exposed to high levels of noise. The study sample included 34 workers with noise-induced hearing impairment. Thresholds of pure-tone audiometry (PTA and Mf-ASSRs at four frequencies were assessed. The differences and correlations between the thresholds of Mf-ASSRs and PTA were determined. The results showed that, on average, Mf-ASSR curves corresponded well with the thresholds of the PTA contours averaged across subjects. The Mf-ASSRs were 20±8 dB, 16±9 dB, 12±9 dB, and 11±12 dB above the thresholds of the PTA for 500 Hz, 1,000 Hz, 2,000 Hz, and 4,000 Hz, respectively. The thresholds of the PTA and the Mf-ASSRs were significantly correlated (r=0.77–0.89. We found that the measurement of Mf-ASSRs is easy and potentially time saving, provides a response at all dichotic multiple frequencies of the conventional audiogram, reduces variability in the interpretation of the responses, and correlates well with the behavioral hearing thresholds in subjects with occupational noise-induced hearing impairment. Mf-ASSR can be a valuable aid in the adjustment of compensation cases.

  5. Insertional events as well as translocations may arise during aberrant immunoglobulin switch recombination in a patient with multiple myeloma.

    Science.gov (United States)

    Pratt, G; Fenton, J A; Davies, F E; Rawstron, A C; Richards, S J; Collins, J E; Owen, R G; Jack, A S; Smith, G M; Morgan, G J

    2001-02-01

    The majority of patients with multiple myeloma have translocations involving the immunoglobulin heavy chain switch regions on chromosome 14q32 and a promiscuous range of partner chromosomes. We describe a patient with an insertion of 132 bp of chromosome 22q12 sequence into the 5' region flanking S(mu) on chromosome 14q32. The 132 bp region from chromosome 22q12 contains the whole of exon 3 from a novel gene of unknown function in man. The significance of such insertional events remains unclear. The description of insertional events occurring as a result of abnormal switch recombination suggests that, in myeloma, dysregulation of oncogenes may occur by a mechanism other than chromosomal translocation.

  6. Calculation of Pareto-optimal solutions to multiple-objective problems using threshold-of-acceptability constraints

    Science.gov (United States)

    Giesy, D. P.

    1978-01-01

    A technique is presented for the calculation of Pareto-optimal solutions to a multiple-objective constrained optimization problem by solving a series of single-objective problems. Threshold-of-acceptability constraints are placed on the objective functions at each stage to both limit the area of search and to mathematically guarantee convergence to a Pareto optimum.

  7. Natural killer cell dependent within-host competition arises during multiple MCMV infection: consequences for viral transmission and evolution.

    Directory of Open Access Journals (Sweden)

    Andrea R McWhorter

    2013-01-01

    Full Text Available It is becoming increasingly clear that many diseases are the result of infection from multiple genetically distinct strains of a pathogen. Such multi-strain infections have the capacity to alter both disease and pathogen dynamics. Infection with multiple strains of human cytomegalovirus (HCMV is common and has been linked to enhanced disease. Suggestions that disease enhancement in multi-strain infected patients is due to complementation have been supported by trans-complementation studies in mice during co-infection of wild type and gene knockout strains of murine CMV (MCMV. Complementation between naturally circulating strains of CMV has, however, not been assessed. In addition, many models of multi-strain infection predict that co-infecting strains will compete with each other and that this competition may contribute to selective transmission of more virulent pathogen strains. To assess the outcome of multi-strain infection, C57BL/6 mice were infected with up to four naturally circulating strains of MCMV. In this study, profound within-host competition was observed between co-infecting strains of MCMV. This competition was MCMV strain specific and resulted in the complete exclusion of certain strains of MCMV from the salivary glands of multi-strain infected mice. Competition was dependent on Ly49H(+ natural killer (NK cells as well as the expression of the ligand for Ly49H, the MCMV encoded product, m157. Strains of MCMV which expressed an m157 gene product capable of ligating Ly49H were outcompeted by strains of MCMV expressing variant m157 genes. Importantly, within-host competition prevented the shedding of the less virulent strains of MCMV, those recognized by Ly49H, into the saliva of multi-strain infected mice. These data demonstrate that NK cells have the strain specific recognition capacity required to meditate within-host competition between strains of MCMV. Furthermore, this within-host competition has the capacity to shape the

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

    NARCIS (Netherlands)

    Kastelein, R.A.; Hoek, L.; Gransier, R.; Jong, C.A.F. de

    2013-01-01

    Pile driving is presently the most common method used to attach wind turbines to the sea bed. To assess the impact of pile driving sounds on harbor porpoises, it is important to know at what distance these sounds can be detected. Using a psychophysical technique, a male porpoise’s hearing thresholds

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

    Science.gov (United States)

    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...

  10. Development of a thresholding algorithm for calcium classification at multiple CT energies

    Science.gov (United States)

    Ng, LY.; Alssabbagh, M.; Tajuddin, A. A.; Shuaib, I. L.; Zainon, R.

    2017-05-01

    The objective of this study was to develop a thresholding method for calcium classification with different concentration using single-energy computed tomography. Five different concentrations of calcium chloride were filled in PMMA tubes and placed inside a water-filled PMMA phantom (diameter 10 cm). The phantom was scanned at 70, 80, 100, 120 and 140 kV using a SECT. CARE DOSE 4D was used and the slice thickness was set to 1 mm for all energies. ImageJ software inspired by the National Institute of Health (NIH) was used to measure the CT numbers for each calcium concentration from the CT images. The results were compared with a developed algorithm for verification. The percentage differences between the measured CT numbers obtained from the developed algorithm and the ImageJ show similar results. The multi-thresholding algorithm was found to be able to distinguish different concentrations of calcium chloride. However, it was unable to detect low concentrations of calcium chloride and iron (III) nitrate with CT numbers between 25 HU and 65 HU. The developed thresholding method used in this study may help to differentiate between calcium plaques and other types of plaques in blood vessels as it is proven to have a good ability to detect the high concentration of the calcium chloride. However, the algorithm needs to be improved to solve the limitations of detecting calcium chloride solution which has a similar CT number with iron (III) nitrate solution.

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

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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.

  13. Multiple-plateau structure and scaling relation in photoelectron spectra of high-order above-threshold ionization

    Institute of Scientific and Technical Information of China (English)

    Wu Yan; Ye Hui-Liang; Zhang Jing-Tao; Guo Dong-Sheng

    2012-01-01

    By developing a full quantum scattering theory of high-order above-threshold ionization,we study the energy spectra and the angular distributions of photoelectrons from atoms with intense laser fields shining on them.We find that real rescattering can occur many times,and even infinite times.The photoelectrons from the rescattering process form a broad plateau in the kinetic-energy spectrum.We further disclose a multiple-plateau structure formed by the high-energy photoelectrons,which absorb many photons during the rescattering process.Moreover,we find that both the angular distributions and the kinetic-energy spectra of photoelectrons obey the same scaling law as that for directly emitted photoelectrons.

  14. A Finite Characterization and Recognition of Intersection Graphs of Hypergraphs with Rank at Most 3 and Multiplicity at Most 2 in the Class of Threshold Graphs

    Directory of Open Access Journals (Sweden)

    Metelsky Yury

    2017-02-01

    Full Text Available We characterize the class L32$L_3^2 $ of intersection graphs of hypergraphs with rank at most 3 and multiplicity at most 2 by means of a finite list of forbidden induced subgraphs in the class of threshold graphs. We also give an O(n-time algorithm for the recognition of graphs from L32$L_3^2 $ in the class of threshold graphs, where n is the number of vertices of a tested graph.

  15. Accelerated parabolic Radon domain 2D adaptive multiple subtraction with fast iterative shrinkage thresholding algorithm and its application in parabolic Radon domain hybrid demultiple method

    Science.gov (United States)

    Li, Zhong-xiao; Li, Zhen-chun

    2017-08-01

    Adaptive multiple subtraction is an important step for successfully conducting surface-related multiple elimination in marine seismic exploration. 2D adaptive multiple subtraction conducted in the parabolic Radon domain has been proposed to better separate primaries and multiples than 2D adaptive multiple subtraction conducted in the time-offset domain. Additionally, the parabolic Radon domain hybrid demultiple method combining parabolic Radon filtering and parabolic Radon domain 2D adaptive multiple subtraction can better remove multiples than the cascaded demultiple method using time-offset domain 2D adaptive multiple subtraction and the parabolic Radon transform method sequentially. To solve the matching filter in the optimization problem with L1 norm minimization constraint of primaries, traditional parabolic Radon domain 2D adaptive multiple subtraction uses the iterative reweighted least squares (IRLS) algorithm, which is computationally expensive for solving a weighted LS inversion in each iteration. In this paper we introduce the fast iterative shrinkage thresholding algorithm (FISTA) as a faster alternative to the IRLS algorithm for parabolic Radon domain 2D adaptive multiple subtraction. FISTA uses the shrinkage-thresholding operator to promote the sparsity of estimated primaries and solves the 2D matching filter with iterative steps. FISTA based parabolic Radon domain 2D adaptive multiple subtraction reduces the computation time effectively while achieving similar accuracy compared with IRLS based parabolic Radon domain 2D adaptive multiple subtraction. Additionally, the provided examples show that FISTA based parabolic Radon domain 2D adaptive multiple subtraction can better separate primaries and multiples than FISTA based time-offset domain 2D adaptive multiple subtraction. Furthermore, we introduce FISTA based parabolic Radon domain 2D adaptive multiple subtraction into the parabolic Radon domain hybrid demultiple method to improve its computation

  16. Tocilizumab and multiple sclerosis: a causal relationship? Clinical Commentary on the case report entitled--MS arising during Tocilizumab therapy for rheumatoid arthritis.

    Science.gov (United States)

    Comabella, Manuel

    2016-02-01

    This clinical commentary discusses on the potential relationship between multiple sclerosis (MS) and tocilizumab in a patient with rheumatoid arthritis who developed MS while on treatment with this anti-interleukin-6 agent.

  17. The Arising of Results

    DEFF Research Database (Denmark)

    Sobisch, Jan-Ulrich

    2013-01-01

    Some Buddhist scholars have periodized the expected lifetime of the Buddha's teachings. According to them, these periods of 500 years each have different characteristics. The first is called 'the period of the results'. Therefore some scholars have claimed that only in the first 500 years after...... the Buddha results can arise. Kyobpa Jigten Sumgön has argued that results arise through practise as long as Dharma and Sangha exist....

  18. Chondroblastoma arising from acromion

    Institute of Scientific and Technical Information of China (English)

    WANG Min; ZHOU Yue; REN Xian-jun; ZHANG Xia; WANG Jian

    2005-01-01

    @@ Chondroblastoma is an uncommon benign tumor arising in the epiphysis of long bones such as humerus, tibia and femur while the skeletal or extraskeletal presentations are mostly unusual. The chondroblastoma arising from acromion process of scapulus has been extremely rare and only two cases can be screened out in the English literature[1,2]. Here, we reported another case of chondroblastoma that developed on the acromion of scapulus.

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

    Science.gov (United States)

    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

  20. Universal threshold enhancement

    CERN Document Server

    Patkós, András; Szépfalusy, P; Szep, Zs.

    2003-01-01

    By assuming certain analytic properties of the propagator, it is shown that universal features of the spectral function including threshold enhancement arise if a pole describing a particle at high temperature approaches in the complex energy plane the threshold position of its two-body decay with the variation of T. The case is considered, when one can disregard any other decay processes. The quality of the proposed description is demonstrated by comparing it with the detailed large N solution of the linear sigma model around the pole-threshold coincidence.

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

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

    2013-01-01

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

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

    Science.gov (United States)

    Huang, Huolin; Liang, Yung Chii

    2015-12-01

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

  4. Performance analysis of a threshold-based parallel multiple beam selection scheme for WDM-based systems for Gamma-Gamma distributions

    KAUST Repository

    Nam, Sung Sik

    2017-03-02

    In this paper, we statistically analyze the performance of a threshold-based parallel multiple beam selection scheme (TPMBS) for Free-space optical (FSO) based system with wavelength division multiplexing (WDM) in cases where a pointing error has occurred for practical consideration over independent identically distributed (i.i.d.) Gamma-Gamma fading conditions. Specifically, we statistically analyze the characteristics in operation under conventional heterodyne detection (HD) scheme for both adaptive modulation (AM) case in addition to non-AM case (i.e., coherentnon-coherent binary modulation). Then, based on the statistically derived results, we evaluate the outage probability (CDF) of a selected beam, the average spectral efficiency (ASE), the average number of selected beams (ANSB), and the average bit error rate (BER). Some selected results shows that we can obtain the higher spectral efficiency and simultaneously reduce the potential increasing of the complexity of implementation caused by applying the selection based beam selection scheme without a considerable performance loss.

  5. Variations in spatial patterns of soil-vegetation properties and the emergence of multiple resilience thresholds within different debris flow fan positions

    Science.gov (United States)

    Mohseni, Neda; Hosseinzadeh, Seyed Reza; Sepehr, Adel; Golzarian, Mahmood Reza; Shabani, Farzin

    2017-08-01

    Debris flow fans are non-equilibrium landforms resulting from the spatial variations of debris flows deposited on them. This geomorphic disturbance involving the asymmetric redistribution of water and sediment may create spatially heterogeneous patterns of soil-vegetation along landforms. In this research, founded on field-based observations, we characterized the spatial patterns of some soil (e.g., particle size distribution including fine and coarse covers, and infiltration capacity) and vegetation (e.g., plant distance, vegetation density, patch size, and average number of patches) properties within different debris flow fan positions (Upper, Middle, and Lower fan) located at the base of the Binaloud Mountain hillslope in northeastern Iran. Thereafter, using a mathematical model of dry land vegetation dynamics, we calculated response trends of the different positions to the same environmental harshness gradient. Field measurements of soil-vegetation properties and infiltration rates showed that the asymmetric redistribution of debris flow depositions can cause statistically significant differences (P plant distance, mean vegetation density, and the average number of patches decreased as the coarse covers increased toward the Lower fan plots. Conversely, an increase in infiltration rate was observed. The simulation results on the aerial images taken from different positions, illustrated that positions with a heterogeneous distribution of vegetation patterns were not desertified to the same degree of aridity. Thus, the Middle and Lower positions could survive under harsher aridity conditions, due to the emergence of more varied spatial vegetation patterns than at the Upper fan position. The findings, based on a combined field and modeling approach, highlighted that debris flow as a geomorphic process with the asymmetric distribution of depositions on the gentle slope of an alluvial fan, can incur multiple resilience thresholds with different degrees of self

  6. Kapteyn series arising in radiation problems

    Energy Technology Data Exchange (ETDEWEB)

    Lerche, I [Institut fuer Geowissenschaften, Naturwissenschaftliche Fakultaet III, Martin-Luther-Universitaet Halle, D-06099 Halle (Germany); Tautz, R C [Institut fuer Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

    2008-01-25

    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.

  7. $\\eta'$ photoproduction near threshold

    CERN Document Server

    Zhao, Q

    2000-01-01

    In this work, the $\\eta^\\prime$ meson photoproduction near threshold is studied in the quark model framework. A pseudovector effective Lagrangian is introduced for the $\\eta^\\prime NN$ coupling and the newly published data from the SAPHIR Collaboration provide good constraints to this parameter. Corrections of order $O(1/m_q^2)$ for the electromagnetic interaction vertex are taken into account, which produce corrections of order $O(1/m_q^3)$ to the transition amplitude for $\\gamma p\\to \\eta^\\prime p$. Some low-lying resonances, $S_{11}(1535)$, $P_{13}(1720)$, and $P_{13}(1900)$ are found to have significant contributions. A bump structure around $E_\\gamma\\approx$ 2 GeV is found arising from the $n=3$ terms in the harmonic oscillator basis. The beam polarization asymmetries are predicted and can be tested against the forthcoming data from GRAAL.

  8. Number theory arising from finite fields analytic and probabilistic theory

    CERN Document Server

    Knopfmacher, John

    2001-01-01

    ""Number Theory Arising from Finite Fields: Analytic and Probabilistic Theory"" offers a discussion of the advances and developments in the field of number theory arising from finite fields. It emphasizes mean-value theorems of multiplicative functions, the theory of additive formulations, and the normal distribution of values from additive functions. The work explores calculations from classical stages to emerging discoveries in alternative abstract prime number theorems.

  9. Laminopathies: Multiple disorders arising from defects in nuclear architecture

    Indian Academy of Sciences (India)

    Veena K Parnaik; Kaliyaperumal Manju

    2006-09-01

    Lamins are the major structural proteins of the nucleus in an animal cell. In addition to being essential for nuclear integrity and assembly, lamins are involved in the organization of nuclear processes such as DNA replication, transcription and repair. Mutations in the human lamin A gene lead to highly debilitating genetic disorders that primarily affect muscle, adipose, bone or neuronal tissues and also cause premature ageing syndromes. Mutant lamins alter nuclear integrity and hinder signalling pathways involved in muscle differentiation and adipocyte differentiation, suggesting tissue-specific roles for lamins. Furthermore, cells expressing mutant lamins are impaired in their response to DNA damaging agents. Recent reports indicate that certain lamin mutations act in a dominant negative manner to cause nuclear defects and cellular toxicity, and suggest a possible role for aberrant lamins in normal ageing processes.

  10. Variability of blood alcohol content (BAC) determinations: the role of measurement uncertainty, significant figures, and decision rules for compliance assessment in the frame of a multiple BAC threshold law.

    Science.gov (United States)

    Zamengo, Luca; Frison, Giampietro; Tedeschi, Gianpaola; Frasson, Samuela; Zancanaro, Flavio; Sciarrone, Rocco

    2014-10-01

    The measurement of blood-alcohol content (BAC) is a crucial analytical determination required to assess if an offence (e.g. driving under the influence of alcohol) has been committed. For various reasons, results of forensic alcohol analysis are often challenged by the defence. As a consequence, measurement uncertainty becomes a critical topic when assessing compliance with specification limits for forensic purposes. The aims of this study were: (1) to investigate major sources of variability for BAC determinations; (2) to estimate measurement uncertainty for routine BAC determinations; (3) to discuss the role of measurement uncertainty in compliance assessment; (4) to set decision rules for a multiple BAC threshold law, as provided in the Italian Highway Code; (5) to address the topic of the zero-alcohol limit from the forensic toxicology point of view; and (6) to discuss the role of significant figures and rounding errors on measurement uncertainty and compliance assessment. Measurement variability was investigated by the analysis of data collected from real cases and internal quality control. The contribution of both pre-analytical and analytical processes to measurement variability was considered. The resulting expanded measurement uncertainty was 8.0%. Decision rules for the multiple BAC threshold Italian law were set by adopting a guard-banding approach. 0.1 g/L was chosen as cut-off level to assess compliance with the zero-alcohol limit. The role of significant figures and rounding errors in compliance assessment was discussed by providing examples which stressed the importance of these topics for forensic purposes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Brieschenk, Stefan [Centre for Hypersonics, The University of Queensland, Brisbane 4072 (Australia); Kleine, Harald; O' Byrne, Sean [The University of New South Wales Canberra, The Australian Defence Force Academy, Canberra 2600 (Australia)

    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.

  12. Primary extradural meningioma arising from the calvarium

    Directory of Open Access Journals (Sweden)

    N Ravi

    2013-06-01

    Full Text Available Meningiomas are the most common intracranial tumours. Meningiomas arising at other locations are termed primary extradural meningiomas (EDM and are rare. Here we report a case of EDM arising from the calvarium – a primary calvarial meningioma (PCM.

  13. Delusional Disorder Arising From a CNS Neoplasm.

    Science.gov (United States)

    Stupinski, John; Kim, Jihye; Francois, Dimitry

    2017-01-01

    Erotomania arising from a central nervous system (CNS) neoplasm has not been previously described. Here, we present the first known case, to our knowledge, of erotomania with associated persecutory delusions arising following diagnosis and treatment of a left frontal lobe brain tumor.

  14. Theory of Auditory Thresholds in Primates

    Science.gov (United States)

    Harrison, Michael J.

    2001-03-01

    The influence of thermal pressure fluctuations at the tympanic membrane has been previously investigated as a possible determinant of the threshold of hearing in humans (L.J. Sivian and S.D. White, J. Acoust. Soc. Am. IV, 4;288(1933).). More recent work has focussed more precisely on the relation between statistical mechanics and sensory signal processing by biological means in creatures' brains (W. Bialek, in ``Physics of Biological Systems: from molecules to species'', H. Flyvberg et al, (Eds), p. 252; Springer 1997.). Clinical data on the frequency dependence of hearing thresholds in humans and other primates (W.C. Stebbins, ``The Acoustic Sense of Animals'', Harvard 1983.) has long been available. I have derived an expression for the frequency dependence of hearing thresholds in primates, including humans, by first calculating the frequency dependence of thermal pressure fluctuations at eardrums from damped normal modes excited in model ear canals of given simple geometry. I then show that most of the features of the clinical data are directly related to the frequency dependence of the ratio of thermal noise pressure arising from without to that arising from within the masking bandwidth which signals must dominate in order to be sensed. The higher intensity of threshold signals in primates smaller than humans, which is clinically observed over much but not all of the human auditory spectrum is shown to arise from their smaller meatus dimensions. note

  15. Sub-threshold synchronizer

    NARCIS (Netherlands)

    Zhou, J.; Ashouei, M.; Kinniment, D.; Huisken, J.; Russell, G.; Yakovlev, A.

    2011-01-01

    Sub-threshold operation has been proven to be very effective to reduce the power consumption of circuits when high performance is not required. Future low power systems on chip are likely to consist of many sub-systems operating at different frequencies and VDDs from super-threshold to sub-threshold

  16. Threshold Concepts in Biochemistry

    Science.gov (United States)

    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…

  17. 多重休假Geo/Geo/1排队的均衡混合门限策略∗%Equilibrium Mixed Threshold Strategies in the Geo/Geo/1 Queue with Multiple Vacations

    Institute of Scientific and Technical Information of China (English)

    马琰; 李继红; 刘维奇

    2013-01-01

    This paper studies the equilibrium mixed threshold strategies of customers in the Geo/Geo/1 queue under multiple vacation policy. Customers decide by themselves whether to join or to balk. A“reward-cost”structure is built and the expected net benefit function is made to reflect the desire of customers for service. Based on the theory of QBD processes, the station-ary system behavior is analyzed. By introducing several proper functions, the mixed threshold strategies are provided and proved to be equilibrium strategies. Finally, we present numerical experiments to demonstrate the sensitivity of the equilibrium mixed thresholds strategies with respect to the system parameters. The results provide useful reference information to managers on the pricing problem in queueing system.%  本文基于多重休假Geo/Geo/1离散时间排队,研究顾客的均衡混合门限策略。强调排队系统中的决策主体是顾客,突破了以往只注重研究服务机构单方面行为的局限。建立了“收入–支出”结构,利用预期净收益函数,量化顾客的决策意愿;根据拟生灭过程理论,对系统进行了稳态分析;进而构造适当的函数,给出了寻找均衡混合门限策略的具体方法,并给予了证明;最后通过数值实验讨论了均衡策略对系统各参数的敏感性。研究结果为管理者探讨排队系统中的定价问题提供了理论参考。

  18. Incorporation of the time aspect into the liability-threshold model for case-control-family data

    DEFF Research Database (Denmark)

    Cederkvist, Luise; Holst, Klaus K.; Andersen, Klaus K.

    2017-01-01

    Familial aggregation and the role of genetic and environmental factors can be investigated through family studies analysed using the liability-threshold model. The liability-threshold model ignores the timing of events including the age of disease onset and right censoring, which can lead...... to estimates that are difficult to interpret and are potentially biased. We incorporate the time aspect into the liability-threshold model for case-control-family data following the same approach that has been applied in the twin setting. Thus, the data are considered as arising from a competing risks setting...... and inverse probability of censoring weights are used to adjust for right censoring. In the case-control-family setting, recognising the existence of competing events is highly relevant to the sampling of control probands. Because of the presence of multiple family members who may be censored at different...

  19. Exact Threshold Circuits

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Podolskii, Vladimir V.

    2010-01-01

    We initiate a systematic study of constant depth Boolean circuits built using exact threshold gates. We consider both unweighted and weighted exact threshold gates and introduce corresponding circuit classes. We next show that this gives a hierarchy of classes that seamlessly interleave with the ......We initiate a systematic study of constant depth Boolean circuits built using exact threshold gates. We consider both unweighted and weighted exact threshold gates and introduce corresponding circuit classes. We next show that this gives a hierarchy of classes that seamlessly interleave...... with the well-studied corresponding hierarchies defined using ordinary threshold gates. A major open problem in Boolean circuit complexity is to provide an explicit super-polynomial lower bound for depth two threshold circuits. We identify the class of depth two exact threshold circuits as a natural subclass...

  20. Synchronous melanomas arising within nevus spilus*

    Science.gov (United States)

    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

  1. Polynomial threshold functions and Boolean threshold circuits

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Podolskii, Vladimir V.

    2013-01-01

    We study the complexity of computing Boolean functions on general Boolean domains by polynomial threshold functions (PTFs). A typical example of a general Boolean domain is 12n . We are mainly interested in the length (the number of monomials) of PTFs, with their degree and weight being...... of secondary interest. We show that PTFs on general Boolean domains are tightly connected to depth two threshold circuits. Our main results in regard to this connection are: PTFs of polynomial length and polynomial degree compute exactly the functions computed by THRMAJ circuits. An exponential length lower...

  2. A Phenomenological Study on Threshold Improvement via Spatial Coupling

    CERN Document Server

    Takeuchi, Keigo; Kawabata, Tsutomu

    2011-01-01

    Kudekar et al. proved an interesting result in low-density parity-check (LDPC) convolutional codes: The belief-propagation (BP) threshold is boosted to the maximum-a-posteriori (MAP) threshold. Furthermore, the authors showed that the BP threshold for code-division multiple-access (CDMA) systems is improved up to a threshold below the optimal one via spatial coupling. In this letter, a phenomenological model for elucidating the essence of these phenomenon, called threshold improvement, is proposed. The main result implies that threshold improvement occurs for spatially-coupled general graphical models.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rasor, Ned S., E-mail: ned.rasor@gmail.com [532 Pauley Woods Circle Kettering, Ohio 45429 (United States)

    2016-08-14

    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.

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

    Science.gov (United States)

    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.

  5. Hydrometeorological threshold conditions for debris flow initiation in Norway

    Directory of Open Access Journals (Sweden)

    N. K. Meyer

    2012-10-01

    Full Text Available Debris flows, triggered by extreme precipitation events and rapid snow melt, cause considerable damage to the Norwegian infrastructure every year. To define intensity-duration (ID thresholds for debris flow initiation critical water supply conditions arising from intensive rainfall or snow melt were assessed on the basis of daily hydro-meteorological information for 502 documented debris flow events. Two threshold types were computed: one based on absolute ID relationships and one using ID relationships normalized by the local precipitation day normal (PDN. For each threshold type, minimum, medium and maximum threshold values were defined by fitting power law curves along the 10th, 50th and 90th percentiles of the data population. Depending on the duration of the event, the absolute threshold intensities needed for debris flow initiation vary between 15 and 107 mm day−1. Since the PDN changes locally, the normalized thresholds show spatial variations. Depending on location, duration and threshold level, the normalized threshold intensities vary between 6 and 250 mm day−1. The thresholds obtained were used for a frequency analysis of over-threshold events giving an estimation of the exceedance probability and thus potential for debris flow events in different parts of Norway. The absolute thresholds are most often exceeded along the west coast, while the normalized thresholds are most frequently exceeded on the west-facing slopes of the Norwegian mountain ranges. The minimum thresholds derived in this study are in the range of other thresholds obtained for regions with a climate comparable to Norway. Statistics reveal that the normalized threshold is more reliable than the absolute threshold as the former shows no spatial clustering of debris flows related to water supply events captured by the threshold.

  6. Provably secure robust threshold partial blind signature

    Institute of Scientific and Technical Information of China (English)

    CAO Zhenfu; ZHU Haojin; LU Rongxing

    2006-01-01

    Threshold digital signature and blind signature are playing important roles in cryptography as well as in practical applications such as e-cash and e-voting systems.Over the past few years, many cryptographic researchers have made considerable headway in this field. However, to our knowledge, most of existing threshold blind signature schemes are based on the discrete logarithm problem. In this paper, we propose a new robust threshold partial blind signature scheme based on improved RSA cryptosystem.This scheme is the first threshold partial blind signature scheme based on factoring, and the robustness of threshold partial blind signature is also introduced. Moreover, in practical application, the proposed scheme will be especially suitable for blind signature-based voting systems with multiple administrators and secure electronic cash systems to prevent their abuse.

  7. Schwannomatosis with Cystic Degeneration Arising from a Single Intercostal Nerve: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kun Woo; Lee, Young Kyung [Dept. of Radiology, Kyung Hee University College of Medicine, Seoul (Korea, Republic of); Kim, Dae Hyun [Dept. of Thoracic and Cardiovascular, Kyung Hee Hospital at Gangdong, Kyung Hee University College of Medicine, Seoul (Korea, Republic of); Sung, Dong Wook [Dept. of Radiology, Kyung Hee Medical Center, Kyung Hee University College of Medicine, Seoul (Korea, Republic of)

    2012-03-15

    An intrathoracic schwannoma is a benign neurogenic tumor that arises from the posterior mediastinum and is commonly found to be solitary. Schwannomatosis that manifests as multiple cysts is extremely rare. In this case study, we report a rare case of a 36-year-old man with no respiratory symptoms, with multiple cystic tumors in the posterior chest wall and pathologically confirmed schwannomatosis with cystic degeneration arising from a single intercostal nerve.

  8. Cutaneous osteosarcoma arising from a burn scar

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Min A.; Yi, Jaehyuck [Kyungpook National University, Department of Radiology, College of Medicine, Daegu (Korea, Republic of); Kyungpook National University Hospital, Department of Radiology, Daegu (Korea, Republic of); Chae, Jong Min [Kyungpook National University, Department of Pathology, College of Medicine, Daegu (Korea, Republic of)

    2017-04-15

    Tumors that develop in old burn scars are usually squamous cell carcinomas. Sarcomas have also been reported, albeit rarely. To our knowledge, there has been only one case report of an extraskeletal osteosarcoma arising in a prior burn scar reported in the English-language literature, mainly discussing the clinicopathological features. Herein, we present a case of cutaneous osteosarcoma visualized as a mineralized soft-tissue mass arising from the scar associated with a previous skin burn over the back. This seems to be the first report describing the imaging features of a cutaneous osteosarcoma from an old burn scar. (orig.)

  9. Threshold Concepts in Economics

    Science.gov (United States)

    Shanahan, Martin

    2016-01-01

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

  10. ARISE: American renaissance in science education

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    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.

  11. Technology arising from High-Energy Physics

    CERN Multimedia

    1974-01-01

    An exibition was held as a part of the Meeting on Technology arising from High- Energy Physics (24-26 April 1974). The Proceedings (including a list of stands) were published as Yellow Report, CERN 74-9, vol. 1-2.

  12. Primary Osteosarcoma of the Breast Arising in an Intraductal Papilloma

    Directory of Open Access Journals (Sweden)

    Khalefa Ali Alghofaily

    2017-01-01

    Full Text Available Introduction. Primary osteosarcoma of the breast is extremely rare, and an osteosarcoma arising from an intraductal papilloma is exceptional. Case Presentation. A 72-year-old Saudi Arabian woman presented with a solid, bone-containing breast mass that was diagnosed as primary osteosarcoma of the breast on biopsy. She had a history of untreated intraductal papilloma. Treatment was completed with a modified mastectomy after excluding extramammary metastases. However, she subsequently developed multiple recurrent lesions at the same site. Conclusion. Primary osteogenic sarcomas of the breast are very rare. Although the main treatment is resection the optimal management remains uncertain and prognosis is poor.

  13. Spectral Distribution of Transport Operator Arising in Growing Cell Populations

    Directory of Open Access Journals (Sweden)

    Hongxing Wu

    2014-01-01

    Full Text Available Transport equation with partly smooth boundary conditions arising in growing cell populations is studied in Lp  (1multiplicities in a trip Γω. The main methods rely on theory of linear operators, comparison operators, and resolvent operators approach.

  14. Ameloblastic Fibrosarcoma Arising in the Maxilla.

    Science.gov (United States)

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

    2016-01-01

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

  15. Sclerosing haemangioma arising within extralobar pulmonary sequestration

    Energy Technology Data Exchange (ETDEWEB)

    Ahmetoglu, Ali; Kosucu, Polat; Guemele, Halit Resit [Department of Radiology, Farabi Hospital, Karadeniz Technical University, 61080 Trabzon (Turkey); Imamoglu, Mustafa; Cay, Ali [Department of Paediatric Surgery, Farabi Hospital, Karadeniz Technical University, Trabzon (Turkey); Reis, Abdulkadir [Department of Pathology, Farabi Hospital, Karadeniz Technical University, Trabzon (Turkey)

    2003-09-01

    Extralobar pulmonary sequestration is a rare anomaly of abnormal pulmonary tissue without any communication to the bronchial tree. Sclerosing haemangioma is a rare lung tumour, generally seen in middle-aged women. The combination of these two rare pathologies has not been previously reported. We describe the CT and CT angiographic findings of sclerosing haemangioma arising within an extralobar pulmonary sequestration in a 2-year-old girl. (orig.)

  16. Conjunctival lymphoma arising from reactive lymphoid hyperplasia

    Directory of Open Access Journals (Sweden)

    Fukuhara Junichi

    2012-09-01

    Full Text Available Abstract Extra nodal marginal zone B-cell lymphoma (EMZL of the conjunctiva typically arises in the marginal zone of mucosa-associated lymphoid tissue. The pathogenesis of conjunctival EMZL remains unknown. We describe an unusual case of EMZL arising from reactive lymphoid hyperplasia (RLH of the conjunctiva. A 35-year-old woman had fleshy salmon-pink conjunctival tumors in both eyes, oculus uterque (OU. Specimens from conjunctival tumors in the right eye, oculus dexter (OD, revealed a collection of small lymphoid cells in the stroma. Immunohistochemically, immunoglobulin (Ig light chain restriction was not detected. In contrast, diffuse atypical lymphoid cell infiltration was noted in the left eye, oculus sinister (OS, and positive for CD20, a marker for B cells OS. The tumors were histologically diagnosed as RLH OD, and EMZL OS. PCR analysis detected IgH gene rearrangement in the joining region (JH region OU. After 11 months, a re-biopsy specimen demonstrated EMZL based on compatible pathological and genetic findings OD, arising from RLH. This case suggests that even if the diagnosis of the conjunctival lymphoproliferative lesions is histologically benign, confirmation of the B-cell clonality by checking IgH gene rearrangement should be useful to predict the incidence of malignancy.

  17. Quantum threshold group signature

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In most situations, the signer is generally a single person. However, when the message is written on behalf of an organization, a valid message may require the approval or consent of several persons. Threshold signature is a solution to this problem. Generally speaking, as an authority which can be trusted by all members does not exist, a threshold signature scheme without a trusted party appears more attractive. Following some ideas of the classical Shamir’s threshold signature scheme, a quantum threshold group signature one is proposed. In the proposed scheme, only t or more of n persons in the group can generate the group signature and any t-1 or fewer ones cannot do that. In the verification phase, any t or more of n signature receivers can verify the message and any t-1 or fewer receivers cannot verify the validity of the signature.

  18. Efficient circular thresholding.

    Science.gov (United States)

    Lai, Yu-Kun; Rosin, Paul L

    2014-03-01

    Otsu's algorithm for thresholding images is widely used, and the computational complexity of determining the threshold from the histogram is O(N) where N is the number of histogram bins. When the algorithm is adapted to circular rather than linear histograms then two thresholds are required for binary thresholding. We show that, surprisingly, it is still possible to determine the optimal threshold in O(N) time. The efficient optimal algorithm is over 300 times faster than traditional approaches for typical histograms and is thus particularly suitable for real-time applications. We further demonstrate the usefulness of circular thresholding using the adapted Otsu criterion for various applications, including analysis of optical flow data, indoor/outdoor image classification, and non-photorealistic rendering. In particular, by combining circular Otsu feature with other colour/texture features, a 96.9% correct rate is obtained for indoor/outdoor classification on the well known IITM-SCID2 data set, outperforming the state-of-the-art result by 4.3%.

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

    Science.gov (United States)

    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

  20. Hydrodynamics of sediment threshold

    Science.gov (United States)

    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.

  1. Angiomyolipoma arising in the gluteal region

    Institute of Scientific and Technical Information of China (English)

    Emmanouil Pikoulis; Constantine Bramis; Othon Mich; George Liapis; Evangelos Felekourasx; Vassiliki Kyriakou; John Griniatsos

    2007-01-01

    @@ Angiomyolipoma (AML) is a tumour of uncertain histogenesis originally believed to be a hamartomatous lesion, but recently recognized as a usually benign clonal mesenchymal neoplasm.1 Along with lymphagiomyomatosis (LAM), clear cell "sugar"tumour (CCST) and clear cell myelomelanocytic tumour (CCMMT), AML was classified in the so called perivascular epithelioid cell (PEComa) neoplasm family.1 Kidney constitutes the principal site of its development.Extrarenal AMLs are rare and to the best of our knowledge, only two cases of AML development in the soft tissues have been reported so far.2,3 We presented a 23 years old female patient with an AML arising in the left gluteal region.

  2. Security risks arising from portable storage devices

    CSIR Research Space (South Africa)

    Molotsi, K

    2012-10-01

    Full Text Available ? To identify and provide security countermeasures to help organisations and users to address the security risks from PSDs DEFINITION OF PORTABLE STORAGE DEVICES A PSD can be defined as: ? A small, lightweight device that is capable of storing... stream_source_info Molotsi_2012.pdf.txt stream_content_type text/plain stream_size 4841 Content-Encoding ISO-8859-1 stream_name Molotsi_2012.pdf.txt Content-Type text/plain; charset=ISO-8859-1 Security risks arising from...

  3. Eccrine Poroma Arising within Nevus Sebaceous

    Directory of Open Access Journals (Sweden)

    Natnicha Girdwichai

    2016-04-01

    Full Text Available 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.

  4. Polynomial threshold functions and Boolean threshold circuits

    DEFF Research Database (Denmark)

    Hansen, Kristoffer Arnsfelt; Podolskii, Vladimir V.

    2013-01-01

    of secondary interest. We show that PTFs on general Boolean domains are tightly connected to depth two threshold circuits. Our main results in regard to this connection are: PTFs of polynomial length and polynomial degree compute exactly the functions computed by THRMAJ circuits. An exponential length lower...... bound for PTFs that holds regardless of degree, thereby extending known lower bounds for THRMAJ circuits. We generalize two-party unbounded error communication complexity to the multi-party number-on-the-forehead setting, and show that communication lower bounds for 3-player protocols would yield size...... lower bounds for THRTHR circuits. We obtain several other results about PTFs. These include relationships between weight and degree of PTFs, and a degree lower bound for PTFs of constant length. We also consider a variant of PTFs over the max-plus algebra. We show that they are connected to PTFs over...

  5. Endogenous thresholds and assurance networks in collective action

    NARCIS (Netherlands)

    De Jaegher, Kris

    2016-01-01

    This article treats a multi-player Stag Hunt where each player may have a different threshold (the number of other players that need to act along with the player for benefits of collective action to arise). Players are modeled as solving the strategic-uncertainty problem of whether or not to act, by

  6. Threshold photodetachment in a repulsive potential

    CERN Document Server

    Lindahl, Anton O; Hultgren, Hannes; Kiyan, Igor Yu; Pegg, David J; Walter, C Wesley; Hanstorp, Dag; 10.1103/PhysRevLett.108.033004

    2012-01-01

    We report on the first experimental observation of a new threshold behavior observed in the 5g partial channel in photodetachment of K-. It arises from the repulsive polarization interaction between the detached electron and the residual K(5g) atom, which has a large negative dipole polarizability. In order to account for the observation in the K(5g) channel, we have developed a semiclassical model that predicts an exponential energy dependence for the cross section. The measurements were made with collinear laser-ion beams and a resonance ionization detection scheme.

  7. Electric current arising from unpolarized polyvinyl formal

    Indian Academy of Sciences (India)

    P K Khare; P L Jain; R K Pandey

    2000-10-01

    An appreciable electric current is observed in a system consisting of a polyvinyl formal (PVF) film in a sandwich configuration, in the temperature range 30–110°C. The maximum value of the current during first heating is found to be of the order of 10–10 A and its thermograms exhibit one transition (i.e. current peak) at around 60°C. The position of the current peak in thermal spectrum shifts with the heating rate. A temperature dependence of the open circuit voltage is also observed. The activation energy of the process responsible for the current is determined. The magnitude of the current is more in the case of dissimilar electrode systems. It is proposed that the electric current arising from unpolarized metal–polymer–metal system is a water activated phenomenon, which is influenced by the transitional changes of the polymer.

  8. Periorbital nodular fasciitis arising during pregnancy

    Directory of Open Access Journals (Sweden)

    Brandon N Phillips

    2014-01-01

    Full Text Available Nodular fasciitis (NF is a benign proliferation of fibroblasts and myofibroblasts that rarely occurs in the periorbital region. We report what we believe to be the first case of periorbital NF associated with pregnancy. A case of intravascular fasciitis, a NF variant, has been reported during pregnancy, but it was not located in the periorbital region. A weak presence of estrogen receptors has been reported in NF. This may make it more susceptible to the hormone-related changes during pregnancy and contribute to the development of the lesion by stimulating fibroblasts and smooth muscle cell types. Although rare, NF should be considered in the differential diagnosis of periorbital soft-tissue masses arising during pregnancy.

  9. High grade angiosarcoma arising in fibroadenoma

    Directory of Open Access Journals (Sweden)

    Babarović Emina

    2011-12-01

    Full Text Available Abstract Primary angiosarcoma of the breast is a rare tumour that account for fewer than 0.05% of all malignant mammary tumours. Angiosarcoma may have an perfidious clinical onset. Radiologic findings are often nonspecific and may appear completely normal in one-third of cases with primary angiosarcoma. The prognosis is usually poor because of the high rates of local recurrence and early development of metastases. Aggressive surgical resection is the mainstay of treatment. The role of adjuvant therapy has not yet been well established. Here we present a case of a 53 year old, postmenopausal women with primary angiosarcoma arising in fibroadenoma. To our knowledge, this is the first case described in the literature to date.

  10. Juxtacortical chondromyxoid fibroma arising in an apophysis

    Energy Technology Data Exchange (ETDEWEB)

    Park, Seong Ho; Kong, Keun Young; Chung, Hye Won; Kang, Heung Sik [Dept. of Radiology, Seoul National University College of Medicine (Korea); Kim, Chong Jai [Dept. of Pathology, Seoul National University College of Medicine, Seoul (Korea); Lee, Sang Hoon [Dept. of Orthopaedic Surgery, Seoul National University College of Medicine, Seoul (Korea)

    2000-08-01

    We present a rare case of juxtacortical chondromyxoid fibroma arising in the lesser trochanter of the right femur which corresponds to an apophysis. Radiography showed a well-defined expansive lesion with a sclerotic margin measuring 5 x 3.5 cm in diameter in the lesser trochanter. On spin echo T1-weighted images, the lesion revealed low signal intensity similar to muscle. On spin echo T2-weighted images, the lesion revealed high heterogeneous signal intensity, which after gadolinium injection showed heterogeneous enhancement. The inner margin of the cortex was intact and adjacent bone marrow was of normal signal intensity. The outer margin of the lesion was also clearly defined and extension into adjacent soft tissue beyond the exophytic cortical outgrowth was not evident. (orig.)

  11. Atherogenic Risk Factors and Hearing Thresholds

    DEFF Research Database (Denmark)

    Frederiksen, Thomas Winther; Ramlau-Hansen, Cecilia Høst; Stokholm, Zara Ann

    2014-01-01

    The objective of this study was to evaluate the influence of atherogenic risk factors on hearing thresholds. In a cross-sectional study we analyzed data from a Danish survey in 2009-2010 on physical and psychological working conditions. The study included 576 white- and blue-collar workers from...... children's day care units, financial services and 10 manufacturing trades. Associations between atherogenic risk factors (blood lipids, glycosylated hemoglobin, smoking habits, body mass index (BMI), and ambulatory blood pressure) and hearing thresholds were analyzed using multiple linear regression models...

  12. Comparison between intensity- duration thresholds and cumulative rainfall thresholds for the forecasting of landslide

    Science.gov (United States)

    Lagomarsino, Daniela; Rosi, Ascanio; Rossi, Guglielmo; Segoni, Samuele; Catani, Filippo

    2014-05-01

    This work makes a quantitative comparison between the results of landslide forecasting obtained using two different rainfall threshold models, one using intensity-duration thresholds and the other based on cumulative rainfall thresholds in an area of northern Tuscany of 116 km2. The first methodology identifies rainfall intensity-duration thresholds by means a software called MaCumBA (Massive CUMulative Brisk Analyzer) that analyzes rain-gauge records, extracts the intensities (I) and durations (D) of the rainstorms associated with the initiation of landslides, plots these values on a diagram, and identifies thresholds that define the lower bounds of the I-D values. A back analysis using data from past events can be used to identify the threshold conditions associated with the least amount of false alarms. The second method (SIGMA) is based on the hypothesis that anomalous or extreme values of rainfall are responsible for landslide triggering: the statistical distribution of the rainfall series is analyzed, and multiples of the standard deviation (σ) are used as thresholds to discriminate between ordinary and extraordinary rainfall events. The name of the model, SIGMA, reflects the central role of the standard deviations in the proposed methodology. The definition of intensity-duration rainfall thresholds requires the combined use of rainfall measurements and an inventory of dated landslides, whereas SIGMA model can be implemented using only rainfall data. These two methodologies were applied in an area of 116 km2 where a database of 1200 landslides was available for the period 2000-2012. The results obtained are compared and discussed. Although several examples of visual comparisons between different intensity-duration rainfall thresholds are reported in the international literature, a quantitative comparison between thresholds obtained in the same area using different techniques and approaches is a relatively undebated research topic.

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

    Science.gov (United States)

    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.

  14. Thick Brane Worlds Arising From Pure Geometry

    CERN Document Server

    Cardenas, R; Cardenas, Rolando; Quiros, Israel

    2002-01-01

    We study a non-Riemannian modification of 5-dimensional Kaluza-Klein theory. In our proposal the Riemannian structure of the five-dimensional manifold is replaced by a Weyl-integrable one. In this context a 4-dimensional Poincar$\\grave{e}$ invariant solution is studied. A spacetime structure with two thick (smooth) branes separated in the extra dimension arises. The massless graviton is located in one of the thick branes at the origin, meanwhile the matter degrees of freedom are confined to the other brane. Due to the small overlap of the graviton's wave-function with the second thick brane, the model accounts for a resolution of the mass hierarchy problem a la Randall-Sundrum. Although, initially, no assumptions are made about the topology of the extra dimension, the solution found yields an extra space that is effectivelly compact and respects $Z_2$ symmetry. Unlike other models with branes, the spectrum of massive Kaluza-Klein states is quantized and free of tachyonic modes.

  15. Chemical hazards arising from shale gas extraction

    Directory of Open Access Journals (Sweden)

    Daria Pakulska

    2015-02-01

    Full Text Available 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 extremely 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. Med Pr 2015;66(1:99–117

  16. Cutaneous leiomyosarcoma arising in a smallpox scar

    Directory of Open Access Journals (Sweden)

    Pol Robert A

    2012-07-01

    Full Text Available Abstract Background Cutaneous leiomyosarcoma (CLM is a very rare smooth muscle tumour that accounts for about 2–3% of all superficial soft tissue sarcomas. Although the development of various malignancies in scar tissue is well known, we report the first case of a CLM developing in a small pox scar. Case presentation A 66-year-old man presented with a painless, slow-growing lump in a small pox scar on his left shoulder. Histological biopsies showed the lesion to be a primary, well-differentiated cutaneous leiomyosarcoma. A CT scan of the thorax was conducted, which showed no signs of metastases. The complete lesion was then surgically excised, and histopathological examination revealed a radically excised cutaneous type leiomyosarcoma After 13 months’ review the patient was doing well with no evidence of tumour recurrence. Conclusions This is the first report of a CLM arising in a small pox scar. Although the extended time interval between scarring and malignant changes makes it difficult to advise strict follow-up for patients with small pox scars, one should be aware that atypical changes and/or symptoms occurring in a small pox scar could potentially mean malignant transformation.

  17. Cutaneous leiomyosarcoma arising in a smallpox scar.

    Science.gov (United States)

    Pol, Robert A; Dannenberg, Hilde; Robertus, Jan-Lukas; van Ginkel, Robert J

    2012-07-16

    Cutaneous leiomyosarcoma (CLM) is a very rare smooth muscle tumour that accounts for about 2-3% of all superficial soft tissue sarcomas. Although the development of various malignancies in scar tissue is well known, we report the first case of a CLM developing in a small pox scar. A 66-year-old man presented with a painless, slow-growing lump in a small pox scar on his left shoulder. Histological biopsies showed the lesion to be a primary, well-differentiated cutaneous leiomyosarcoma. A CT scan of the thorax was conducted, which showed no signs of metastases. The complete lesion was then surgically excised, and histopathological examination revealed a radically excised cutaneous type leiomyosarcoma After 13 months' review the patient was doing well with no evidence of tumour recurrence. This is the first report of a CLM arising in a small pox scar. Although the extended time interval between scarring and malignant changes makes it difficult to advise strict follow-up for patients with small pox scars, one should be aware that atypical changes and/or symptoms occurring in a small pox scar could potentially mean malignant transformation.

  18. Quantum discord of states arising from graphs

    Science.gov (United States)

    Dutta, Supriyo; Adhikari, Bibhas; Banerjee, Subhashish

    2017-08-01

    Quantum discord refers to an important aspect of quantum correlations for bipartite quantum systems. In our earlier works, we have shown that corresponding to every graph (combinatorial) there are quantum states whose properties are reflected in the structure of the corresponding graph. Here, we attempt to develop a graph theoretic study of quantum discord that corresponds to a necessary and sufficient condition of zero quantum discord states which says that the blocks of density matrix corresponding to a zero quantum discord state are normal and commute with each other. These blocks have a one-to-one correspondence with some specific subgraphs of the graph which represents the quantum state. We obtain a number of graph theoretic properties representing normality and commutativity of a set of matrices which are indeed arising from the given graph. Utilizing these properties, we define graph theoretic measures for normality and commutativity that results in a formulation of graph theoretic quantum discord. We identify classes of quantum states with zero discord using the developed formulation.

  19. An organism arises from every nucleus.

    Directory of Open Access Journals (Sweden)

    Nurullah Keklikoglu

    2009-12-01

    Full Text Available The fact that, cloning using somatic cell nuclear transfer (SCNT method has been performed, opened new horizons for cloning, and changed the way of our understanding and approach to cell and nucleus. The progress in cloning technology, brought the anticipation of the ability to clone an organism from each somatic cell nucleus. Therefore, the 'Cell Theory' is about to take the additional statement as "An organism arises from every nucleus". The development of gene targeting procedures which can be applied with SCNT, showed us that it may be possible to obtain different versions of the original genetic constitution of a cell. Because of this opportunity which is provided by SCNT, in reproductive cloning, it would be possible to clone enhanced organisms which can adapt to different environmental conditions and survive. Furthermore, regaining the genetic characteristics of ancestors or reverse herediter variations would be possible. On the other hand, in therapeutic cloning, more precise and easily obtainable alternatives for cell replacement therapy could be presented. However, while producing healthier or different organisms from a nucleus, it is hard to foresee the side effects influencing natural processes in long term is rather difficult.

  20. Efficient Threshold Signature Scheme

    Directory of Open Access Journals (Sweden)

    Sattar J Aboud

    2012-01-01

    Full Text Available In this paper, we introduce a new threshold signature RSA-typed scheme. The proposed scheme has the characteristics of un-forgeable and robustness in random oracle model. Also, signature generation and verification is entirely non-interactive. In addition, the length of the entity signature participate is restricted by a steady times of the length of the RSA signature modulus. Also, the signing process of the proposed scheme is more efficient in terms of time complexity and interaction.

  1. The abundance threshold for plague as a critical percolation phenomenon.

    Science.gov (United States)

    Davis, S; Trapman, P; Leirs, H; Begon, M; Heesterbeek, J A P

    2008-07-31

    Percolation theory is most commonly associated with the slow flow of liquid through a porous medium, with applications to the physical sciences. Epidemiological applications have been anticipated for disease systems where the host is a plant or volume of soil, and hence is fixed in space. However, no natural examples have been reported. The central question of interest in percolation theory, the possibility of an infinite connected cluster, corresponds in infectious disease to a positive probability of an epidemic. Archived records of plague (infection with Yersinia pestis) in populations of great gerbils (Rhombomys opimus) in Kazakhstan have been used to show that epizootics only occur when more than about 0.33 of the burrow systems built by the host are occupied by family groups. The underlying mechanism for this abundance threshold is unknown. Here we present evidence that it is a percolation threshold, which arises from the difference in scale between the movements that transport infectious fleas between family groups and the vast size of contiguous landscapes colonized by gerbils. Conventional theory predicts that abundance thresholds for the spread of infectious disease arise when transmission between hosts is density dependent such that the basic reproduction number (R(0)) increases with abundance, attaining 1 at the threshold. Percolation thresholds, however, are separate, spatially explicit thresholds that indicate long-range connectivity in a system and do not coincide with R(0) = 1. Abundance thresholds are the theoretical basis for attempts to manage infectious disease by reducing the abundance of susceptibles, including vaccination and the culling of wildlife. This first natural example of a percolation threshold in a disease system invites a re-appraisal of other invasion thresholds, such as those for epidemic viral infections in African lions (Panthera leo), and of other disease systems such as bovine tuberculosis (caused by Mycobacterium bovis) in

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ryo Niyuki

    2017-03-01

    Full Text Available 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.

  4. Threshold properties of a microcavity laser with submicroampere threshold current

    Energy Technology Data Exchange (ETDEWEB)

    Choquette, K.D.; Hou, H.Q.; Lear, K.L.; Chow, W.W.; Mar, A.; Geib, K.M.; Hammons, B.E.

    1996-02-01

    We report the threshold characteristics of small oxide-confined vertical-cavity surface emitting lasers. Abrupt threshold transitions 105 times the spontaneous emission background are obtained at injection currents as low as 470 nanoampere.

  5. Cost-effectiveness thresholds: pros and cons.

    Science.gov (United States)

    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.

  6. Threshold concepts in finance: conceptualizing the curriculum

    Science.gov (United States)

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

    2015-08-01

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

  7. Higgs-Stoponium Mixing Near the Stop-Antistop Threshold

    CERN Document Server

    Bodwin, Geoffrey T; Wagner, Carlos E M

    2016-01-01

    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 ...

  8. Hadron production near threshold

    Indian Academy of Sciences (India)

    B K Jain; N G Kelkar; K P Khmemchandani

    2006-04-01

    Final state interaction effects in → + and → 3He reactions are explored near threshold to study the sensitivity of the cross-sections to the potential and the scattering matrix. The final state scattering wave functions between and and and 3He are described rigorously. The production is described by the exchange of one pion and a -meson between two protons in the incident channel. The production is described by a two-step model, where in the first step a pion is produced. This pion then produces an by interacting with another nucleon.

  9. Neuroendocrine carcinomas arising in ulcerative colitis: coincidences or possible correlations?

    Science.gov (United States)

    Grassia, Roberto; Bodini, Paolo; Dizioli, Paolo; Staiano, Teresa; Iiritano, Elena; Bianchi, Guglielmo; Buffoli, Federico

    2009-09-07

    Patients with inflammatory bowel disease (IBD) are at increased risk of colorectal malignancies. Adenocarcinoma is the commonest type of colorectal neoplasm associated with ulcerative colitis (UC) and Crohn's disease, but other types of epithelial and non-epithelial tumors have also been described in inflamed bowel. With regards to non-epithelial malignancies, lymphomas and sarcomas represent the largest group of tumors reported in association with IBD, especially in immunosuppressed patients. Carcinoids and in particular neuroendocrine neoplasms other than carcinoids (NENs) are rare tumors and are infrequently described in the setting of IBD. Thus, this association requires further investigation. We report two cases of neoplasms arising in mild left-sided UC with immunohistochemical staining for neuroendocrine markers: a large cell and a small cell neuroendocrine carcinoma of the rectum. The two patients were different in age (35 years vs 77 years) and disease duration (11 years vs 27 years), and both had never received immunosuppressant drugs. Although the patients underwent regular endoscopic and histological follow-up, the two neoplasms were locally advanced at diagnosis. One of the two patients developed multiple liver metastases and died 15 mo after diagnosis. These findings confirm the aggressiveness and the poor prognosis of NENs compared to colorectal adenocarcinoma. While carcinoids seem to be coincidentally associated with IBD, NENs may also arise in this setting. In fact, long-standing inflammation could be directly responsible for the development of pancellular dysplasia involving epithelial, goblet, Paneth and neuroendocrine cells. It has yet to be established which IBD patients have a higher risk of developing NENs.

  10. A case of hepatocellular carcinoma arising within large focal nodular hyperplasia with review of the literature

    Institute of Scientific and Technical Information of China (English)

    Theodoros Petsas; Athanassios Tsamandas; Irene Tsota; Dionisios Karavias; Chrysoula Karatza; Vassilios Vassiliou; Dimitrios Kardamakis

    2006-01-01

    Focal nodular hyperplasia (FNH) is a relatively rare benign hepatic tumor, usually presenting as a solitary lesion; however, multiple localizations have also been described. The association of FNH with other hepatic lesions, such as adenomas and haemangiomas has been reported by various authors. We herein report a case of a hepatocellular carcinoma arising within a large focal nodular hyperplasia, in a young female patient.

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

    Science.gov (United States)

    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.

  12. Land-use change arising from rural land exchange : an agent-based simulation model

    NARCIS (Netherlands)

    Bakker, Martha M.; Alam, Shah Jamal; van Dijk, Jerry; Rounsevell, Mark D. A.

    2015-01-01

    Land exchange can be a major factor driving land-use change in regions with high pressure on land, but is generally not incorporated in land-use change models. Here we present an agent-based model to simulate land-use change arising from land exchange between multiple agent types representing farmer

  13. Threshold Generation of Signcryption

    Institute of Scientific and Technical Information of China (English)

    ZHANGFutai; JIDongyao; WANGYumin

    2003-01-01

    Signcryption is a new cryptographic primitive wiich simultaneously fulfills both the functions of digital signature and public key encryption in a logically singlestep,and with a cost significantly lower than that required by "signature followed by encryption".It has many applications in such areas as electronic cash payment systems,secure and authenticated key establishment,secure multicasting over the Internet,authenticated key recovery,etc..In secure and authenticated group communication there is a need for threshold generation of signcryption.In this paper,we propose a protocol for threshold generation of signcryption using the techniques of verifiable secret sharing(VSS)and secure multi-party computation (MPC).In the protocol,any t or more honest members can efficiently generate valid signcryption text of a given message,while the adversary whole corrupts up to t-1 group members cannot forge any valid signcryption text.The protocol of computing reciprocals of secrets presented by R.Gennaro,S.Jarecki,H.Krawczyk,and T.Rabin is also modified so that the efficiency is improved.

  14. Coloring geographical threshold graphs

    Energy Technology Data Exchange (ETDEWEB)

    Bradonjic, Milan [Los Alamos National Laboratory; Percus, Allon [Los Alamos National Laboratory; Muller, Tobias [EINDHOVEN UNIV. OF TECH

    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.

  15. Microinvasive lobular carcinoma arising in a fibroadenoma.

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Oscillatory threshold logic.

    Science.gov (United States)

    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.

  18. Mathematical problems arising in interfacial electrohydrodynamics

    Science.gov (United States)

    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

  19. Catastrophic Thresholds: A Synthesis of Concepts, Perspectives, and Applications

    Directory of Open Access Journals (Sweden)

    David D. Briske

    2010-09-01

    Full Text Available Research reported in this feature identifies a convergence of interpretations regarding the threshold dynamics of complex ecological systems. This convergence has arisen from a diverse set of investigations addressing rangeland ecosystem dynamics, disease transmission, and fluctuations in the populations of insect pests. Effective application of the threshold concept to ecosystem management will require development of more robust linkages between non-equilibrium theory and protocols to identify triggers that initiate threshold conditions, feedback loops that establish system resilience, and developmental trajectories and attributes of potential alternative stable states. Successful implementation of these theory/application linkages has the potential to underpin an operational framework of resilience-based ecosystem management that is founded upon the identification of structural indicators that are correlated with vulnerability or proximity to thresholds, rather than threshold identification per se. Several investigations indicate that thresholds are strongly influenced by scale; multiple cross-scale interactions demonstrate the need for greater knowledge and analyses to address scale-dependent processes, i.e., critical scales and scaling laws. This feature emphasizes the relevance of thresholds and non-equilibrium dynamics in multiple natural resource management applications and in so doing demonstrates the need for a more comprehensive and integrated ecological framework capable of quantitatively assessing dynamics at multiple scales to inform management and policy recommendations for optimal management and risk assessment.

  20. IR multiple-photon excitation of C2H5F and 1,1-C2H4F2 near dissociation threshold: vibrational emissions from parent and product species

    Energy Technology Data Exchange (ETDEWEB)

    Caballero, J.F.; Wittig, C.

    1981-08-15

    The IR multiple photon excitation and dissociation of C2H5F and 1,1-C2H4F2 has been studied by monitoring vibrational fluorescence in the region 2000-4000 cm following excitation with the focused output from a CO2 TEA laser. 21 references, 2 figures.

  1. Crossing Thresholds: Identifying conceptual transitions in postsecondary teaching

    Directory of Open Access Journals (Sweden)

    Susan Wilcox

    2013-12-01

    Full Text Available In this paper we report on research we conducted to begin the process of identifying threshold concepts in the field of postsecondary teaching. Meyer & Land (2006 propose that within all disciplinary fields there seem to be particular threshold concepts that serve as gateways, opening up new and previously inaccessible ways of thinking and practicing. We developed a series of questions focusing on the “troublesome” and “transformative” characteristics of threshold concepts and asked these questions of several constituent groups, including those who are new to practice and the body of knowledge in postsecondary teaching and those who are already knowledgeable and/or experienced in the field. Based on our interpretation of participants’ responses, we identified four recognized concepts in the field of postsecondary teaching as potential threshold concepts in this field: Assessment for/as learning; Learning-centred teaching; Accommodation for diversity; and, Context-driven practice. Our findings suggest that threshold concepts are relevant to the field of postsecondary teaching. Through this work, we hope to help educational developers and faculty members consider what is involved in learning to teach and developing teaching expertise, and to encourage critical discussion about the teaching development “curriculum” in postsecondary settings. Threshold concepts arise as a field develops and are defined as practitioners and scholars in the field define their field. At this stage, we believe the real value of threshold concepts for postsecondary teaching lies in the discussion that arises in the process of identifying and naming the concepts.

  2. Osteochondroma arising from a lumbar facet joint in a 16-year-old.

    Science.gov (United States)

    Hancock, Graeme E; Mariathas, Chrishan; Fernandes, James A; Breakwell, Lee M; Cole, Ashley A; Michael, Antony L R

    2015-05-01

    Osteochondromas are benign tumours of bony or cartilaginous origin, which may be solitary or multiple. They are rare in the axial skeleton and have previously been reported to arise from facet joints only in four cases in the English literature. We report the case of a 16-year-old girl who presented with a palpable bony lump and a short history of back pain. Imaging showed a bony lesion arising from a left-sided facet joint in the lumbar spine. Following excision biopsy, there was complete resolution of symptoms. The literature on the origin and management of spinal osteochondromas is discussed.

  3. Lower Hearing Threshold by Noise

    Institute of Scientific and Technical Information of China (English)

    龙长才; 邵峰; 张燕萍; 秦佑国

    2004-01-01

    We demonstrate that noise can be a benefit factor that enables us to hear weaker signals. We measured the hearing thresholds of subjects for pure tone in different noise levels. The results show that pure tone thresholds with noise of some levels are lower than that without noise. The largest down-shift of the threshold by noise among the examined subjects is 5. 7dB, and the smallest is 1.7dB.

  4. MD 751: Train Instability Threshold

    CERN Document Server

    Carver, Lee Robert; Metral, Elias; Salvant, Benoit; Levens, Tom; Nisbet, David; Zobov, M; CERN. Geneva. ATS Department

    2016-01-01

    The purpose of this MD is to measure the octupole current thresholds for stability for a single bunch, and then make an immediate comparison (with the same operational settings) for a train of 72 bunches separated by 25ns. From theory, the expected thresholds should be similar. Any discrepancy between the two cases will be of great interest as it could indicate the presence of additional mechanisms that contribute to the instability threshold, for example electron cloud.

  5. Mob control models of threshold collective behavior

    CERN Document Server

    Breer, Vladimir V; Rogatkin, Andrey D

    2017-01-01

    This book presents mathematical models of mob control with threshold (conformity) collective decision-making of the agents. Based on the results of analysis of the interconnection between the micro- and macromodels of active network structures, it considers the static (deterministic, stochastic and game-theoretic) and dynamic (discrete- and continuous-time) models of mob control, and highlights models of informational confrontation. Many of the results are applicable not only to mob control problems, but also to control problems arising in social groups, online social networks, etc. Aimed at researchers and practitioners, it is also a valuable resource for undergraduate and postgraduate students as well as doctoral candidates specializing in the field of collective behavior modeling.

  6. Wilms tumor arising in extracoelomic paravertebral soft tissues.

    LENUS (Irish Health Repository)

    Mulligan, Linda

    2012-02-01

    Extrarenal Wilms tumor (ERWT) is a well-established entity which most commonly arises within the genitourinary tract, including intracoelomic paranephric soft tissue. Rarely, ERWT arises within teratoma, and it tends to occur predominantly in distinct settings, such as females with spinal defects and males with testicular teratomas. We report a unique ERWT arising within an extracoelomic teratoma of the paraspinal musculature, thereby expanding the range of reported locations for this unusual tumor.

  7. Albania - Thresholds I and II

    Data.gov (United States)

    Millennium Challenge Corporation — From 2006 to 2011, the government of Albania (GOA) received two Millennium Challenge Corporation (MCC) Threshold Programs totaling $29.6 million. Albania received...

  8. Fast Quasi-Threshold Editing

    CERN Document Server

    Brandes, Ulrik; Strasser, Ben; Wagner, Dorothea

    2015-01-01

    We introduce Quasi-Threshold Mover (QTM), an algorithm to solve the quasi-threshold (also called trivially perfect) graph editing problem with edge insertion and deletion. Given a graph it computes a quasi-threshold graph which is close in terms of edit count. This edit problem is NP-hard. We present an extensive experimental study, in which we show that QTM is the first algorithm that is able to scale to large real-world graphs in practice. As a side result we further present a simple linear-time algorithm for the quasi-threshold recognition problem.

  9. A Multiscale Estimation Method of SignalBased on Multiple Threshold Processing%基于多阈值处理的信号多尺度估计算法

    Institute of Scientific and Technical Information of China (English)

    胡长流

    2001-01-01

    A multiscale estimation method of signal based on multiplethreshold processing is presented. First, the original measurement signal is decomposed with multiscale wavelet transform. Then the detail signals on each scale are further decomposed into sub-detail signals and sub-smoothing signals which are proce ssed with different thresholds respectively. The smoothing signals on the coarsest scale are processed with Kalman filtering and reconstructed with the details ignal on each scale. At last, the signal estimate value on the original scale is obtained.%给出了一种基于多阈值处理的信号多尺度估计算法。首先对原始测量进行多尺度小波分解,得出各尺度上的平滑信号和细节信号。对各尺度上的细节信号再作进一步的小波分解,对分解出的次平滑信号和次细节信号进行不同的阈值处理,然后重构,作为相应尺度上的细节信号。最后对最粗尺度上的平滑信号作卡尔曼滤波,再依次与各尺度上的细节信号进行重构,最后得到原始尺度上的信号估计值。

  10. Ecohydrology on the Threshold?

    Science.gov (United States)

    Wainwright, John

    2013-04-01

    This presentation suggests that there are three major limitations to the development of ecohydrology as a coherent disciplinary area. One of the principal controls and feedbacks on patterns of plants and water in the environment is the form of the landscape and landscape-forming processes. Yet (eco)geomorphology is typically overlooked as a topic for ecohydrological investigation. Thus, the process domains used to explain patterns is typically overly restricted. As surface change controls the connectivity of other process, this restriction is significant. However, even when surface change is incorporated, there is often an emphasis on subdisciplinary areas, so that the investigation of patterns across process domains is not carried out in a holistic way. For example, studies of the feedbacks of vegetation on flow resistance are carried out significantly differently when considering wind and water flows (and indeed differently for water flows on hillslopes compared to in channels). Human action is the most important global control on ecohydrology, either from a top-down perspective through climate change, or from a bottom-up perspective through land use and land-use change. The actions of people on ecohydrological and ecogeomorphic processes, though, are typically considered in a static way. Techniques of agent-based modelling are being developed to overcome this limitation, but there need to be parallel developments in field techniques to address the data requirements and empirical underpinnings of such approaches. I argue that to cross the threshold into becoming a more mature discipline ecohydrology/ecogeomorphology needs to take on board the limitations of representations of process, pattern and people. Using examples from studies of land degradation in drylands, as well as from more temperate settings, I will suggest how progress may start to be made.

  11. Life below the threshold.

    Science.gov (United States)

    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.

  12. Interevent Correlations from Avalanches Hiding Below the Detection Threshold

    Science.gov (United States)

    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.

  13. Second threshold in weak interactions

    NARCIS (Netherlands)

    Veltman, M.J.G.

    1977-01-01

    The point of view that weak interactions must have a second threshold below 300 – 600 GeV is developed. Above this threshold new physics must come in. This new physics may be the Higgs system, or some other nonperturbative system possibly having some similarities to the Higgs system. The limit of la

  14. Threshold Concepts and Information Literacy

    Science.gov (United States)

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

    2011-01-01

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

  15. Threshold Concepts and Information Literacy

    Science.gov (United States)

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

    2011-01-01

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

  16. Spin multiplicities

    Energy Technology Data Exchange (ETDEWEB)

    Curtright, T.L., E-mail: curtright@miami.edu [Department of Physics, University of Miami, Coral Gables, FL 33124-8046 (United States); Van Kortryk, T.S., E-mail: vankortryk@gmail.com [Department of Physics, University of Miami, Coral Gables, FL 33124-8046 (United States); High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439-4815 (United States); Zachos, C.K., E-mail: zachos@anl.gov [Department of Physics, University of Miami, Coral Gables, FL 33124-8046 (United States); High Energy Physics Division, Argonne National Laboratory, Argonne, IL 60439-4815 (United States)

    2017-02-05

    The number of times spin s appears in the Kronecker product of n spin j representations is computed, and the large n asymptotic behavior of the result is obtained. Applications are briefly sketched. - Highlights: • We give a self-contained derivation of the spin multiplicities that occur in n-fold tensor products of spin-j representations. • We make use of group characters, properties of special functions, and asymptotic analysis of integrals. • We emphasize patterns that arise when comparing different values of j, and asymptotic behavior for large n. • Our methods and results should be useful for various statistical and quantum information theory calculations.

  17. Lipopolysaccharide-deficient Brucella variants arise spontaneously during infection

    Directory of Open Access Journals (Sweden)

    Joshua E. Turse

    2011-03-01

    Full Text Available Lipopolysaccharide-deficient mutants of smooth Brucella species (rough mutants have been shown to arise spontaneously in culture. However, in situ analysis of Brucella infected macrophages using antibody directed against O-polysaccharide suggested a loss of reactivity of Brucella consistent with the appearance of rough organisms, and a potential contribution to infection. The experiments reported describe the direct recovery of Brucella from macrophages infected in vitro and from the spleens of infected mice at a frequency similar to that described in vitro, suggesting that Brucella dissociation is not simply an in vitro artifact. The frequency of appearance of spontaneous rough organisms deficient in O-polysaccharide expression measured in vitro is approximately 2-3 logs higher than the appearance of mutation to antibiotic resistance, purine auxotrophy or reversion of erythritol sensitive ∆eryC mutants to tolerance. Genetic trans-complementation using a plasmid-based expression of Brucella manBA successfully restored O-polysaccharide expression in only one third of O-polysaccharide deficient spontaneous mutants. Suggesting that the appearance of rough mutants is caused by mutation at more than one locus. In addition, Sanger sequencing of the manBA structural genes detected multiple sequence changes that may explain the observed phenotypic differences. The presence of O-polysaccharide resulted in macrophage and neutrophil infiltration into the peritoneal cavity and systemic distribution of the organism. In contrast, rough organisms are controlled by resident macrophages or by extracellular killing mechanisms and rapidly cleared from this compartment consistent with the inability to cause disease. Loss of O-polysaccharide expression appears to be stochastic giving rise to organisms with biological properties distinct from the parental smooth organism during the course of infection.

  18. Learning regulatory programs by threshold SVD regression.

    Science.gov (United States)

    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.

  19. Rainfall thresholds for possible landslide occurrence in Italy

    Science.gov (United States)

    Peruccacci, Silvia; Brunetti, Maria Teresa; Gariano, Stefano Luigi; Melillo, Massimo; Rossi, Mauro; Guzzetti, Fausto

    2017-08-01

    The large physiographic variability and the abundance of landslide and rainfall data make Italy an ideal site to investigate variations in the rainfall conditions that can result in rainfall-induced landslides. We used landslide information obtained from multiple sources and rainfall data captured by 2228 rain gauges to build a catalogue of 2309 rainfall events with - mostly shallow - landslides in Italy between January 1996 and February 2014. For each rainfall event with landslides, we reconstructed the rainfall history that presumably caused the slope failure, and we determined the corresponding rainfall duration D (in hours) and cumulated event rainfall E (in mm). Adopting a power law threshold model, we determined cumulated event rainfall-rainfall duration (ED) thresholds, at 5% exceedance probability, and their uncertainty. We defined a new national threshold for Italy, and 26 regional thresholds for environmental subdivisions based on topography, lithology, land-use, land cover, climate, and meteorology, and we used the thresholds to study the variations of the rainfall conditions that can result in landslides in different environments, in Italy. We found that the national and the environmental thresholds cover a small part of the possible DE domain. The finding supports the use of empirical rainfall thresholds for landslide forecasting in Italy, but poses an empirical limitation to the possibility of defining thresholds for small geographical areas. We observed differences between some of the thresholds. With increasing mean annual precipitation (MAP), the thresholds become higher and steeper, indicating that more rainfall is needed to trigger landslides where the MAP is high than where it is low. This suggests that the landscape adjusts to the regional meteorological conditions. We also observed that the thresholds are higher for stronger rocks, and that forested areas require more rainfall than agricultural areas to initiate landslides. Finally, we

  20. Music effect on pain threshold evaluated with current perception threshold

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    AIM: Music relieves anxiety and psychotic tension. This effect of music is applied to surgical operation in the hospital and dental office. It is still unclear whether this music effect is only limited to the psychological aspect but not to the physical aspect or whether its music effect is influenced by the mood or emotion of audience. To elucidate these issues, we evaluated the music effect on pain threshold by current perception threshold (CPT) and profile of mood states (POMC) test. METHODS: Healthy 30 subjects (12 men, 18 women, 25-49 years old, mean age 34.9) were tested. (1)After POMC test, all subjects were evaluated pain threshold with CPT by Neurometer (Radionics, USA) under 6 conditions, silence, listening to the slow tempo classic music, nursery music, hard rock music, classic paino music and relaxation music with 30 seconds interval. (2)After Stroop color word test as the stresser, pain threshold was evaluated with CPT under 2 conditions, silence and listening to the slow tempo classic music. RESULTS: Under litening to the music, CPT sores increased, especially 2 000 Hz level related with compression, warm and pain sensation. Type of music, preference of music and stress also affected CPT score. CONCLUSION: The present study demonstrated that the concentration on the music raise the pain threshold and that stress and mood influence the music effect on pain threshold.

  1. Parton distributions with threshold resummation

    CERN Document Server

    Bonvini, Marco; Rojo, Juan; Rottoli, Luca; Ubiali, Maria; Ball, Richard D; Bertone, Valerio; Carrazza, Stefano; Hartland, Nathan P

    2015-01-01

    We construct a set of parton distribution functions (PDFs) in which fixed-order NLO and NNLO calculations are supplemented with soft-gluon (threshold) resummation up to NLL and NNLL accuracy respectively, suitable for use in conjunction with any QCD calculation in which threshold resummation is included at the level of partonic cross sections. These resummed PDF sets, based on the NNPDF3.0 analysis, are extracted from deep-inelastic scattering, Drell-Yan, and top quark pair production data, for which resummed calculations can be consistently used. We find that, close to threshold, the inclusion of resummed PDFs can partially compensate the enhancement in resummed matrix elements, leading to resummed hadronic cross-sections closer to the fixed-order calculation. On the other hand, far from threshold, resummed PDFs reduce to their fixed-order counterparts. Our results demonstrate the need for a consistent use of resummed PDFs in resummed calculations.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-01-01

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

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

    Science.gov (United States)

    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.

  4. The thresholds for statistical and clinical significance

    DEFF Research Database (Denmark)

    Jakobsen, Janus Christian; Gluud, Christian; Winkel, Per

    2014-01-01

    threshold if the trial is stopped early or if interim analyses have been conducted; (4) adjust the confidence intervals and the P-values for multiplicity due to number of outcome comparisons; and (5) assess clinical significance of the trial results. CONCLUSIONS: If the proposed five-step procedure...... not reflect the probability of getting a result assuming an alternative hypothesis to the null hypothesis is true. Second, a confidence interval or a P-value showing significance may be caused by multiplicity. Third, statistical significance does not necessarily result in clinical significance. Therefore......, assessment of intervention effects in randomised clinical trials deserves more rigour in order to become more valid. METHODS: Several methodologies for assessing the statistical and clinical significance of intervention effects in randomised clinical trials were considered. Balancing simplicity...

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

    Science.gov (United States)

    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.

  6. Jacobians with complex multiplication

    CERN Document Server

    Carocca, Angel; Rodriguez, Rubi E

    2009-01-01

    We construct and study two series of curves whose Jacobians admit complex multiplication. The curves arise as quotients of Galois coverings of the projective line with Galois group metacyclic groups $G_{q,3}$ of order $3q$ with $q \\equiv 1 \\mod 3$ an odd prime, and $G_m$ of order $2^{m+1}$. The complex multiplications arise as quotients of double coset algebras of the Galois groups of these coverings. We work out the CM-types and show that the Jacobians are simple abelian varieties.

  7. Threshold proxy quantum signature scheme with threshold shared verification

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A threshold proxy quantum signature scheme with threshold shared verification is proposed. An original signer could authorize a group as its proxy signers. Then only t or more of n persons in the proxy group can generate the proxy signature on behalf of the original signer and any t-1 or fewer ones cannot do that. When the proxy signature needs to be verified,any t or more of n persons belonging to the verification group can verify the message and any t-1 or fewer ones cannot verify the validity of the proxy signature.

  8. Inclusive distributions near kinematic thresholds

    CERN Document Server

    Gardi, E

    2006-01-01

    The main challenge in computing inclusive cross sections and decay spectra in QCD is posed by kinematic thresholds. The threshold region is characterized by stringent phase-space constraints that are reflected in large perturbative corrections due to soft and collinear radiation as well as large non-perturbative effects. Major progress in addressing this problem was made in recent years by Dressed Gluon Exponentiation (DGE), a formalism that combines Sudakov and renormalon resummation in moment space. DGE has proven effective in extending the range of applicability of perturbation theory well into the threshold region and in identifying the relevant non-perturbative corrections. Here we review the method from a general perspective using examples from deep inelastic structure functions, event-shape distributions, heavy-quark fragmentation and inclusive decay spectra. A special discussion is devoted to the applications of DGE to radiative and semileptonic B decays that have proven valuable for the interpretatio...

  9. Threshold concepts in dental education.

    Science.gov (United States)

    Kinchin, I M; Cabot, L B; Kobus, M; Woolford, M

    2011-11-01

    The paper presents a conceptual framework to inform dental education. Drawing from a vast body of research into student learning, the simple model presented here has an explanatory value in describing what is currently observed to happen and a predictive value in guiding future teaching practices. We introduce to dental education the application of threshold concepts that have a transformative role in offering a new vision of the curriculum that helps to move away from the medieval transmission model of higher education towards a dual processing model that better reflects the way in which professionals operate within the discipline. Threshold concepts give a role for the student voice in offering a novice perspective which is paradoxically something that is out of reach of the subject expert. Finally, the application of threshold concepts highlights some of the weaknesses in the competency-based training model of clinical teaching. 2011 John Wiley & Sons A/S.

  10. Baryon Form Factors at Threshold

    Energy Technology Data Exchange (ETDEWEB)

    Baldini Ferroli, Rinaldo [Museo Storico della Fisica e Centro Studi e Ricerche ' E. Fermi' , Rome (Italy); INFN, Laboratori Nazionali di Frascati, Frascati (Italy); Pacetti, Simone [INFN and Dipartimento di Fisica, Universita di Perugia, Perugia (Italy)

    2012-04-15

    An extensive study of the e{sup +}e{sup -}{yields}pp{sup Macron }BABAR cross section data is presented. Two unexpected outcomes have been found: the modulus of the proton form factor is normalized to one at threshold, i.e.: |G{sup p}(4M{sub p}{sup 2})|=1, as a pointlike fermion, and the resummation factor in the Sommerfeld formula is not needed. Other e{sup +}e{sup -} {yields} baryon-antibaryon cross sections show a similar behavior near threshold.

  11. On computational Gestalt detection thresholds.

    Science.gov (United States)

    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.

  12. Isolated primary malignant lymphoma arising from the optic chiasm.

    Science.gov (United States)

    Tsutsumi, Keiji; Horiuchi, Tetsuyoshi; Aoyama, Tatsuro; Hongo, Kazuhiro

    2013-12-01

    Isolated primary malignant lymphoma rarely arises from the anterior visual pathway. A 59-year-old previously healthy man presented with progressive, painless, bilateral visual disturbance. Neurological imaging revealed an enhancing mass arising from the optic chiasm. Open biopsy was carried out under monitoring of visual evoked potentials and a histopathological diagnosis of diffuse large B-cell lymphoma was made. As systemic examination did not show any evidence of systemic lymphoma, we concluded that this patient had an isolated primary malignant lymphoma at the anterior visual pathway.

  13. Papillary Carcinoma Arising from the Pyramidal Lobe of the Thyroid

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun Gi; Lee, Sarah; Kim, Eun Kyung; Moon, Hee Jung; Kwak, Jin Young [Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    2012-03-15

    The authors present a rare case of papillary carcinoma arising from the pyramidal lobe of the thyroid in a 54-year-old woman, who presented with a right submental palpable mass. An ultrasound evaluation depicted a 3 cm mixed echoic mass from the thyroid cartilage level without a focal lesion in the thyroid gland. Surgical specimens obtained during bilateral thyroidectomy confirmed papillary carcinoma of the pyramidal lobe. To the authors' knowledge, this is the first case report to describe papillary carcinoma arising from the pyramidal lobe of the thyroid gland

  14. Methodology for determination of two new sensory thresholds: Compromised acceptance threshold and rejection threshold.

    Science.gov (United States)

    Lima Filho, Tarcísio; Minim, Valéria Paula Rodrigues; Silva, Rita de Cássia Dos Santos Navarro da; Della Lucia, Suzana Maria; Minim, Luis Antônio

    2015-10-01

    The existing methodologies for determining thresholds generate unreliable estimates of the point at which the intensity of a stimulus begins to compromise acceptance or result in sensory rejection of a product. Thus, a new methodology was proposed for determination of two new sensory thresholds: the compromised acceptance threshold (CAT) and the rejection threshold (RT). In this new methodology, increasing or decreasing series of stimulus intensity are measured together with a standard stimulus (control sample) by means of acceptance tests. In the present study, the CAT and RT were determined for sucrose concentrations in grape nectar, demonstrating that when reducing the sucrose concentration of grape nectar form 9.00% (w/v) to 6.87% there begins to occur impairment of product acceptance (CAT), and when reducing the sucrose concentration from 9.00% to 3.83% there begins to occur sensory rejection (RT) of the product. When compared to existing threshold determination methodologies, the proposed methodology permitted for calculating, with greater reliability, the points at which compromise of acceptance (CAT) and sensory rejection (RT) of the product begin to occur. In addition to the case study presented, the proposed methodology has a wide range of applications in science and in the food, cosmetic and pharmaceutical industries. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Role of near threshold resonances in intermediate energy nuclear physics

    Indian Academy of Sciences (India)

    B K Jain; N J Upadhyay

    2014-11-01

    The presence of a resonance close to the threshold strongly effects the dynamics of the interacting particles at low energies. Production of 12C, the element for life, in 4He burning in Sun is a classic example of such a situation. In intermediate energy nuclear physics, this situation arises in the interactions of an -meson with a nucleon and that of a −-meson with a proton at low energies, where both these systems have a resonance or a bound state near their thresholds, resulting in a strong attractive interaction. If putting these mesons in nuclear environment produces a strong attraction, it is possible that, in nature there may exist - and −-nuclear bound states. Such a tantalizing possibility has led to experimental and theoretical programmes to search for them. These efforts have produced positive results. This paper gives a brief critical overview of these studies, emphasizing especially the efforts led by Bhabha Atomic Research Centre (BARC).

  16. Twist1 activity thresholds define multiple functions in limb development

    OpenAIRE

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

    2010-01-01

    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...

  17. Beamspace root estimator bank for DOA estimation with an improved threshold performance

    OpenAIRE

    Vasylyshyn, V. I.

    2014-01-01

    A beamspace root modification of pseudorandom joint estimation strategy (PR-JES) with using of the outlier identification and cure technique is presented. This technique allows identifying and rectifying the outliers that can arise in the direction-of-arrival (DOA) estimation by eigenstructure methods. It improves the performance of beamspace root estimator bank in the threshold region of signal-to-noise ratio.

  18. QCD threshold corrections for gluino pair production at hadron colliders

    Energy Technology Data Exchange (ETDEWEB)

    Langenfeld, Ulrich [Wuerzburg Univ. (Germany); Moch, Sven-Olaf; Pfoh, Torsten [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2012-11-15

    We present the complete threshold enhanced predictions in QCD for the total cross section of gluino pair production at hadron colliders at next-to-next-to-leading order. Thanks to the computation of the required one-loop hard matching coefficients our results are accurate to the next-to-next-to-leading logarithm. In a brief phenomenological study we provide predictions for the total hadronic cross sections at the LHC and we discuss the uncertainties arising from scale variations and the parton distribution functions.

  19. Lower Bound on Weights of Large Degree Threshold Functions

    CERN Document Server

    Podolskii, Vladimir V

    2012-01-01

    An integer polynomial $p$ of $n$ variables is called a \\emph{threshold gate} for the Boolean function $f$ of $n$ variables if for all $x \\in \\{0,1\\}^n$ $f(x)=1$ if and only if $p(x)\\geq 0$. The \\emph{weight} of a threshold gate is the sum of its absolute values. In this paper we study how large weight might be needed if we fix some function and some threshold degree. We prove $2^{\\Omega(2^{2n/5})}$ lower bound on this value. The best previous bound was $2^{\\Omega(2^{n/8})}$ (Podolskii, 2009). In addition we present substantially simpler proof of the weaker $2^{\\Omega(2^{n/4})}$ lower bound. This proof is conceptually similar to other proofs of the bounds on weights of nonlinear threshold gates, but avoids a lot of technical details arising in other proofs. We hope that this proof will help to show the ideas behind the construction used to prove these lower bounds.

  20. The Nature of Psychological Thresholds

    NARCIS (Netherlands)

    Rouder, Jeffrey N.; Morey, Richard D.

    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

  1. Weights of Exact Threshold Functions

    DEFF Research Database (Denmark)

    Babai, László; Hansen, Kristoffer Arnsfelt; Podolskii, Vladimir V.

    2010-01-01

    We consider Boolean exact threshold functions defined by linear equations, and in general degree d polynomials. We give upper and lower bounds on the maximum magnitude (absolute value) of the coefficients required to represent such functions. These bounds are very close and in the linear case...

  2. Threshold enhancement of diphoton resonances

    Directory of Open Access Journals (Sweden)

    Aoife Bharucha

    2016-10-01

    Full Text Available We revisit a mechanism to enhance the decay width of (pseudo-scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. Motivated by the recent LHC data, indicating the presence of an excess in the diphoton spectrum at approximately 750 GeV, we illustrate this threshold enhancement mechanism in the case of a 750 GeV pseudoscalar boson A with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 12MA threshold and a small decay width, <1 MeV. The implications of such a threshold enhancement are discussed in two explicit scenarios: i the Minimal Supersymmetric Standard Model in which the A state is produced via the top quark mediated gluon fusion process and decays into photons predominantly through loops of charginos with masses close to 12MA and ii a two Higgs doublet model in which A is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. In both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the A resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

  3. Threshold Concepts and Pedagogic Representation

    Science.gov (United States)

    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…

  4. A Secure Threshold Group Signature Scheme

    Institute of Scientific and Technical Information of China (English)

    Wang Xiaoming; Fu Fangwei

    2003-01-01

    The threshold group signature is an important kind of signature. So far, many threshold group signature schemes have been proposed, but most of them suffer from conspiracy attack and are insecure. In this paper, a secure threshold group signature scheme is proposed. It can not only satisfy the properties of the threshold group signature, but also withstand the conspiracy attack

  5. Fusion of Thresholding Rules During Wavelet-Based Noisy Image Compression

    Directory of Open Access Journals (Sweden)

    Bekhtin Yury

    2016-01-01

    Full Text Available The new method for combining semisoft thresholding rules during wavelet-based data compression of images with multiplicative noise is suggested. The method chooses the best thresholding rule and the threshold value using the proposed criteria which provide the best nonlinear approximations and take into consideration errors of quantization. The results of computer modeling have shown that the suggested method provides relatively good image quality after restoration in the sense of some criteria such as PSNR, SSIM, etc.

  6. A NOVEL THRESHOLD BASED EDGE DETECTION ALGORITHM

    Directory of Open Access Journals (Sweden)

    Y. RAMADEVI,

    2011-06-01

    Full Text Available Image segmentation is the process of partitioning/subdividing a digital image into multiple meaningful regions or sets of pixels regions with respect to a particular application. Edge detection is one of the frequently used techniques in digital image processing. The level to which the subdivision is carried depends on theproblem being viewed. Edges characterize boundaries and are therefore a problem of fundamental importance in image processing. There are many ways to perform edge detection. In this paper different Edge detection methods such as Sobel, Prewitt, Robert, Canny, Laplacian of Gaussian (LOG are used for segmenting the image. Expectation-Maximization (EM algorithm, OSTU and Genetic algorithms are also used. A new edge detection technique is proposed which detects the sharp and accurate edges that are not possible with the existing techniques. The proposed method with different threshold values for given input image is shown that ranges between 0 and 1 and it are observed that when the threshold value is 0.68 the sharp edges are recognised properly.

  7. Multi-objective convex programming problem arising in multivariate ...

    African Journals Online (AJOL)

    user

    International Journal of Engineering, Science and Technology. Vol. ... However, although the consideration of multiple objectives may seem a novel concept, virtually any nontrivial, real world problem invariably involves multiple objectives.

  8. The Perils of a Defective Medical Communication: Fatal Neglected Squamous Cell Carcinoma Arising in Perineal Hidradenitis Suppurativa

    Directory of Open Access Journals (Sweden)

    Calogero Pagliarello

    2011-01-01

    Full Text Available Hidradenitis suppurativa (HS is a recurrent suppurative disease characterized by inflammatory nodules, abscesses, fistulas, and scarring. We report a case of squamous cell carcinoma arising in chronic HS. In our case the asymptomatic lesion was neglected by the patient for a long time, allowing the occurrence of advanced disease before treatment was sought, which resulted in a terminal outcome. In the context of HS, a painful lump or ulcer could easily be mistaken for an inflammatory lesion, and therefore a low threshold for biopsy is warranted.

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

    Science.gov (United States)

    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.

  10. Elicitation threshold of cobalt chloride

    DEFF Research Database (Denmark)

    Fischer, Louise A; Johansen, Jeanne D; Voelund, Aage

    2016-01-01

    BACKGROUND: Cobalt is a strong skin sensitizer (grade 5 of 5 in the guinea-pig maximization test) that is used in various industrial and consumer applications. To prevent sensitization to cobalt and elicitation of allergic cobalt dermatitis, information about the elicitation threshold level...... of cobalt is important. OBJECTIVE: To identify the dermatitis elicitation threshold levels in cobalt-allergic individuals. MATERIALS AND METHODS: Published patch test dose-response studies were reviewed to determine the elicitation dose (ED) levels in dermatitis patients with a previous positive patch test...... reaction to cobalt. A logistic dose-response model was applied to data collected from the published literature to estimate ED values. The 95% confidence interval (CI) for the ratio of mean doses that can elicit a reaction in 10% (ED(10)) of a population was calculated with Fieller's method. RESULTS...

  11. Threshold electrodisintegration of 3He

    Science.gov (United States)

    Hicks, R. S.; Hotta, A.; Churchwell, S.; Jiang, X.; Peterson, G. A.; Shaw, J.; Asavapibhop, B.; Berisso, M. C.; Bosted, P. E.; Burchesky, K.; Miskimen, R. A.; Rock, S. E.; Nakagawa, I.; Tamae, T.; Suda, T.; Golak, J.; Skibiński, R.; Witała, H.; Casagrande, F.; Turchinetz, W.; Cichocki, A.; Wang, K.; Glöckle, W.; Kamada, H.; Kobayashi, T.; Nogga, A.

    2003-06-01

    Cross sections were measured for the near-threshold electrodisintegration of 3He at momentum transfer values of q=2.4, 4.4, and 4.7 fm-1. From these and prior measurements the transverse and longitudinal response functions RT and RL were deduced. Comparisons are made against previously published and new nonrelativistic A=3 calculations using the best available nucleon-nucleon NN potentials. In general, for q<2 fm-1 these calculations accurately predict the threshold electrodisintegration of 3He. Agreement at increasing q demands consideration of two-body terms, but discrepancies still appear at the highest momentum transfers probed, perhaps due to the neglect of relativistic dynamics, or to the underestimation of high-momentum wave-function components.

  12. A Rare Nasopharyngeal Teratoma Arising From the Vomer.

    Science.gov (United States)

    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.

  13. Acute Lymphoblastic Leukemia Arising in CALR Mutated Essential Thrombocythemia

    Directory of Open Access Journals (Sweden)

    Stephen E. Langabeer

    2016-01-01

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

  14. Threshold enhancement of diphoton resonances

    Science.gov (United States)

    Bharucha, Aoife; Djouadi, Abdelhak; Goudelis, Andreas

    2016-10-01

    We revisit a mechanism to enhance the decay width of (pseudo-)scalar resonances to photon pairs when the process is mediated by loops of charged fermions produced near threshold. Motivated by the recent LHC data, indicating the presence of an excess in the diphoton spectrum at approximately 750 GeV, we illustrate this threshold enhancement mechanism in the case of a 750 GeV pseudoscalar boson A with a two-photon decay mediated by a charged and uncolored fermion having a mass at the 1/2MA threshold and a small decay width, photons predominantly through loops of charginos with masses close to 1/2MA and ii) a two Higgs doublet model in which A is again produced by gluon fusion but decays into photons through loops of vector-like charged heavy leptons. In both these scenarios, while the mass of the charged fermion has to be adjusted to be extremely close to half of the A resonance mass, the small total widths are naturally obtained if only suppressed three-body decay channels occur. Finally, the implications of some of these scenarios for dark matter are discussed.

  15. Hepatic artery pseudoaneurysms arising from within a hepatocellular carcinoma

    Science.gov (United States)

    Chingkoe, C M; Chang, S D; Legiehn, G M; Weiss, A

    2010-01-01

    We report a case of a 70-year-old man with a large hepatocellular carcinoma (HCC) containing two pseudoaneurysms measuring up to 2 cm in diameter. The pseudoaneurysms and part of the HCC were supplied by branches from the middle colic artery, which arises from the superior mesenteric artery. This complex arterial vasculature was visualised on CT and confirmed with conventional angiography. PMID:21088082

  16. Solitary osteochondroma arising from cervical spina bifida occulta.

    Science.gov (United States)

    Ofluoglu, Ali Ender; Abdallah, Anas; Gokcedag, Akin

    2013-01-01

    Solitary osteochondromas are common benign long bone tumors originating from cartilage. They may produce a wide variety of symptoms and complications depending on their spinal location. These may include compressive myelopathy, nerve root compression, pathologic fracture and malignant degeneration, or in some cases only pain. Solitary cervical spine osteochondromas have been reported mostly in the neural arch or vertebral body. This report describes a patient presenting with neck pain, with a benign osteochondroma arising in the right bifid C5 lamina.

  17. Multicentric glioblastoma arising in two unusual sites : cerebellum and thalamus

    OpenAIRE

    Cambruzzi, Eduardo; Pêgas,Karla Lais; Simão,Mariana Fernandez; Stüker, Guilherme

    2013-01-01

    Multicentric glioblastomas (MGBM) arising in infra/supratentorial regions are uncommon lesions. The authors report a case of MGBM in a 61 year-old female patient, who presented a sudden onset of left hemiplegia. The magnetic resonance imaging (MRI) showed two expansive large lesions affecting cerebellum and thalamus, with strong contrast enhancement. The patient underwent resection of the cerebellar lesion. Microscopy revealed a high grade glial neoplasm exhibiting high mitotic index, areas o...

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

    Science.gov (United States)

    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.

  19. Poorly Differentiated Squamous Cell Carcinoma Arising in Tattooed Skin

    OpenAIRE

    Deba P. Sarma; Dentlinger, Renee B.; Forystek, Amanda M.; Todd Stevens; Christopher Huerter

    2011-01-01

    Introduction. Tattoos have increasingly become accepted by mainstream Western society. As a result, the incidence of tattoo-associated dermatoses is on the rise. The presence of a poorly differentiated squamous cell carcinoma in an old tattooed skin is of interest as it has not been previously documented. Case Presentation. A 79-year-old white homeless man of European descent presented to the dermatology clinic with a painless raised nodule on his left forearm arising in a tattooed area. A...

  20. Penile squamous cell carcinoma arising from balanitis xerotica obliterans.

    Science.gov (United States)

    Pride, H B; Miller, O F; Tyler, W B

    1993-09-01

    Squamous cell carcinoma arising from balanitis xerotica obliterans is rarely reported. We describe an 83-year-old man in whom metastatic penile squamous cell carcinoma developed after 18 years of observation for balanitis xerotica obliterans. It is important to recognize the possibility of this uncommon complication of balanitis xerotica obliterans, because survival of patients with squamous cell carcinoma depends on early diagnosis and treatment.

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

    Science.gov (United States)

    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).

  2. Pooling optimal combinations of energy thresholds in spectroscopic CT

    Science.gov (United States)

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

    2014-03-01

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

  3. Synergistic action on hypnosia: Yinao capsules with pentobarbital sodium of threshold and sub-threshold dosages

    Institute of Scientific and Technical Information of China (English)

    Guilan Zhang; Mingsan Miao; Jingjing Shi; Yalei Yang

    2007-01-01

    7 days continuously, and they were placed into the mice spontaneous activity apparatus after 60 minutes from the last administration, the times of spontaneous activities and the times of arising within 10 minutes were recorded after adaptation for 5 minutes.mice were randomly divided into 5 groups as above-mentioned with 14 mice in each group, and they were treated the same as above. They were intraperitoneally injected with 50 mg/kg pentobarbital sodium after 60 minutes from the last administration, then conditions of falling asleep were observed. The disappearance of righting reflex was taken as the index of falling asleep, the latency of falling asleep was the duration from intraperitoneal injection of pentobarbital sodium to fall asleep, the sleeping time was from falling asleep to sodium of sub-threshold dosage: Eighty mice were randomly divided into 5 groups as above-mentioned with 16 mice in each group, and they were treated the same as above. They were intraperitoneally injected with 27 mg/kg pentobarbital sodium after 60 minutes from the last administration. Mice whose righting reflex disappeared for at least 1 minute within 30 minutes were taken as falling asleep, the number of sleeping animals in each group was recorded, and the rate of falling asleep was calculated.MAIN OUTCOME MEASURES: Synergistic action of Yinao capsules with pentobarbital sodium of threshold and sub-threshold dosages in hypnosia and sedation.spontaneous activity of mice: The times of spontaneous activities within 10 minutes in the large and middle dosage of Yinao capsules groups and Kangnaoshuai capsules group [( 138.0 ± 37.0), (156.8 ± 28.3), (133.3 ±46.1) times] were obviously fewer than those in the control group [(204.3±61.3) times, P < 0.05 -0.01].The arising times within 10 minutes in the middle and small dosages of Yinao capsules groups and Kangnaoshuai capsules group [(30.7 ± 18.3), (26.5 ± 11.2), (24.2± 11.6) times] were obviously fewer than pentobarbital sodium of

  4. Cascades in the Threshold Model for varying system sizes

    Science.gov (United States)

    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.

  5. Rainfall thresholds for the possible occurrence of landslides in Italy

    Directory of Open Access Journals (Sweden)

    M. T. Brunetti

    2010-03-01

    Full Text Available In Italy, rainfall is the primary trigger of landslides that frequently cause fatalities and large economic damage. Using a variety of information sources, we have compiled a catalogue listing 753 rainfall events that have resulted in landslides in Italy. For each event in the catalogue, the exact or approximate location of the landslide and the time or period of initiation of the slope failure is known, together with information on the rainfall duration D, and the rainfall mean intensity I, that have resulted in the slope failure. The catalogue represents the single largest collection of information on rainfall-induced landslides in Italy, and was exploited to determine the minimum rainfall conditions necessary for landslide occurrence in Italy, and in the Abruzzo Region, central Italy. For the purpose, new national rainfall thresholds for Italy and new regional rainfall thresholds for the Abruzzo Region were established, using two independent statistical methods, including a Bayesian inference method and a new Frequentist approach. The two methods proved complementary, with the Bayesian method more suited to analyze small data sets, and the Frequentist method performing better when applied to large data sets. The new regional thresholds for the Abruzzo Region are lower than the new national thresholds for Italy, and lower than the regional thresholds proposed in the literature for the Piedmont and Lombardy Regions in northern Italy, and for the Campania Region in southern Italy. This is important, because it shows that landslides in Italy can be triggered by less severe rainfall conditions than previously recognized. The Frequentist method experimented in this work allows for the definition of multiple minimum rainfall thresholds, each based on a different exceedance probability level. This makes the thresholds suited for the design of probabilistic schemes for the prediction of rainfall-induced landslides. A scheme based on four

  6. Piercing of Consciousness as a Threshold-Crossing Operation.

    Science.gov (United States)

    Kang, Yul H R; Petzschner, Frederike H; Wolpert, Daniel M; Shadlen, Michael N

    2017-08-07

    Many decisions arise through an accumulation of evidence to a terminating threshold. The process, termed bounded evidence accumulation (or drift diffusion), provides a unified account of decision speed and accuracy, and it is supported by neurophysiology in human and animal models. In many situations, a decision maker may not communicate a decision immediately and yet feel that at some point she had made up her mind. We hypothesized that this occurs when an accumulation of evidence reaches a termination threshold, registered, subjectively, as an "aha" moment. We asked human participants to make perceptual decisions about the net direction of dynamic random dot motion. The difficulty and viewing duration were controlled by the experimenter. After indicating their choice, participants adjusted the setting of a clock to the moment they felt they had reached a decision. The subjective decision times (tSDs) were faster on trials with stronger (easier) motion, and they were well fit by a bounded drift-diffusion model. The fits to the tSDs alone furnished parameters that fully predicted the choices (accuracy) of four of the five participants. The quality of the prediction provides compelling evidence that these subjective reports correspond to the terminating process of a decision rather than a post hoc inference or arbitrary report. Thus, conscious awareness of having reached a decision appears to arise when the brain's representation of accumulated evidence reaches a threshold or bound. We propose that such a mechanism might play a more widespread role in the "piercing of consciousness" by non-conscious thought processes. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. 40 CFR 98.361 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Manure Management § 98.361 Reporting threshold. Livestock facilities must report GHG emissions under this subpart if the facility meets the reporting threshold as defined in...

  8. Threshold Effects And Perturbative Unification

    CERN Document Server

    Bastero-Gil, M; Pérez-Mercader, J

    1995-01-01

    We discuss the effect of the renormalization procedure in the computation of the unification point for running coupling constants. We explore the effects of threshold--crossing on the $\\beta$--functions. We compute the running of the coupling constants of the Standard Model, between $m_Z$ and $M_P$, using a mass dependent subtraction procedure, and then compare the results with $\\bar{MS}$, and with the $\\theta$-- function approximation. We also do this for the Minimal Supersymmetric extension of the Standard Model. In the latter, the bounds on susy masses that one obtains by requiring perturbative unification are dependent, to some extent, on the procedure.

  9. Circular threshold quantum secret sharing

    Institute of Scientific and Technical Information of China (English)

    Yang Yu-Guang; Wen Qiao-Yan

    2008-01-01

    This paper proposes a circular threshold quantum secret sharing (TQSS) scheme with polarized single photons.A polarized single photon sequence runs circularly among any t or more of n parties and any t or more of n parties can reconstruct the secret key when they collaborate.It shows that entanglement is not necessary for quantum secret sharing.Moreover,the theoretic efficiency is improved to approach 100% as the single photons carrying the secret key are deterministically forwarded among any t or more of n parties,and each photon can carry one bit of information without quantum storage.This protocol is feasible with current technology.

  10. Ultra-low threshold polariton condensation

    CERN Document Server

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

    2016-01-01

    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.

  11. [Carcinoma arising within mammary fibroadenomas. A study of six patients].

    Science.gov (United States)

    Tissier, F; De Roquancourt, A; Astier, B; Espie, M; Clot, P; Marty, M; Janin, A

    2000-03-01

    We report six cases of carcinomas arising within fibroadenomas. Fibroadenoma is a benign neoplasm occurring in young women. Its association with carcinomas is unfrequent and particularly reported in older women. Few data are available on the histologic features of fibroadenomas harboring malignant lesions. In this study, most cases of fibroadenomas showed cysts, sclerosing adenosis, epithelial calcifications or papillary apocrine changes. These fibroadenomas are classified as complex and are a long-term risk factor for breast cancer. The complex fibroadenoma may be specific of fibroadenoma associated with carcinoma.

  12. Syphilitic gumma arising in association with foreign material.

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Ciulla Michele M

    2003-01-01

    Full Text Available Abstract 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.

  14. Facial Cellulitis Arising from Dens Evaginatus: A Case Report

    Directory of Open Access Journals (Sweden)

    Chun-Ming Chen

    2005-07-01

    Full Text Available Dens evaginatus is a developmental anomaly that produces a tubercle on the occlusal surface of a tooth. It is found most frequently in the mandibular premolars. The occlusal tubercle easily causes occlusal interferences. Attrition or fracture of the tubercle can lead to pulpitis, pulp necrosis, periapical pathosis, and periapical infection. This case report illustrates the treatment of facial cellulitis arising from dens evaginatus with open apex. Calcium hydroxide was used for the apexification procedure. One year after canal obturation, radiography revealed no apical pathosis and the apical seal was evident.

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

    Science.gov (United States)

    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.

  16. Solitary fibrous tumor arising in an intrathoracic goiter

    DEFF Research Database (Denmark)

    Larsen, Stine Rosenkilde; Godballe, Christian; Krogdahl, Annelise

    2010-01-01

    . CONCLUSION: The histological appearance and immunohistochemical reaction pattern of SFT is characteristic. The entity should be considered when dealing with a spindle cell lesion in the thyroid gland. All cases of this site of origin reported have had a benign clinical course. As only a small number of cases......BACKGROUND: Solitary fibrous tumor (SFT) is a rare spindle cell tumor most often found in the mediastinal pleura. Nineteen cases of SFT arising in the thyroid gland have been reported. We report a case of SFT of the thyroid gland with immunohistochemical and cytogenetic investigation. SUMMARY: A 58...

  17. Semigroups and their topologies arising from Green's left quasiorder

    Directory of Open Access Journals (Sweden)

    Bettina Richmond

    2008-10-01

    Full Text Available Given a semigroup (S, ·, Green’s left quasiorder on S is given by a ≤ b if a = u · b for some u ϵ S1. We determine which topological spaces with five or fewer elements arise as the specialization topology from Green’s left quasiorder for an appropriate semigroup structure on the set. In the process, we exhibit semigroup structures that yield general classes of finite topological spaces, as well as general classes of topological spaces which cannot be derived from semigroup structures via Green’s left quasiorder.

  18. Magnetic contrast in threshold photoemission electron microscopy

    NARCIS (Netherlands)

    Veghel, Marinus Godefridus Adrianus van

    2004-01-01

    In threshold photoemission electron microscopy (threshold PEEM), photoelectrons are excited by UV photons with an energy just above the photoemission threshold. The lateral intensity distribution of these electrons is then imaged by an electrostatic lens system. In this thesis, the possibilities o

  19. Threshold Concepts in Finance: Student Perspectives

    Science.gov (United States)

    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…

  20. Threshold Concepts in Finance: Student Perspectives

    Science.gov (United States)

    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…

  1. Iterative wavelet thresholding for rapid MRI reconstruction

    Science.gov (United States)

    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.

  2. STRONGLY COLORED NOISE IN THE DYE LASER FAR ABOVE THRESHOLD

    Institute of Scientific and Technical Information of China (English)

    朱士群

    1991-01-01

    The intensity fluctuations of a single mode ,dye laser is investigated when the laser is operated far above threshold.The analytic result of the laser intensity correlation function is obtained when both the additive white and strongly multiplicative colored noise are included in the laser model .The analyses show clearly the dependence of the intensity fluctuations on the strength and time scale of the pump noise.

  3. Threshold temperature optical fibre sensors

    Science.gov (United States)

    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.

  4. Poorly Differentiated Squamous Cell Carcinoma Arising in Tattooed Skin

    Directory of Open Access Journals (Sweden)

    Deba P. Sarma

    2010-01-01

    Full Text Available Introduction. Tattoos have increasingly become accepted by mainstream Western society. As a result, the incidence of tattoo-associated dermatoses is on the rise. The presence of a poorly differentiated squamous cell carcinoma in an old tattooed skin is of interest as it has not been previously documented. Case Presentation. A 79-year-old white homeless man of European descent presented to the dermatology clinic with a painless raised nodule on his left forearm arising in a tattooed area. A biopsy of the lesion revealed a poorly differentiated squamous cell carcinoma infiltrating into a tattoo. The lesion was completely excised and the patient remains disease-free one year later. Conclusion. All previous reports of squamous cell carcinomas arising in tattoos have been well-differentiated low-grade type or keratoacanthoma-type and are considered to be coincidental rather than related to any carcinogenic effect of the tattoo pigments. Tattoo-associated poorly differentiated invasive carcinoma appears to be extremely rare.

  5. Myoepithelial carcinoma arising in recurrent pleomorphic adenoma in maxillary sinus.

    Science.gov (United States)

    Gupta, Ashumi; Manipadam, Marie Therese; Michael, Rajiv

    2013-09-01

    Myoepithelial carcinoma is characterized by nearly exclusive myoepithelial differentiation and evidence of malignancy. It may arise de novo or in preexisting benign tumors including pleomorphic adenoma and benign myoepithelioma. A 39-year-old lady presented with painless progressive swelling on the right cheek and right side of palate. On surgery, there was a mass in right maxillary sinus which was surgically excised and diagnosed on histopathology as pleomorphic adenoma. Subsequently, there were two recurrences. The first recurrence was in the right maxilla after 2 years that was removed surgically and diagnosed as pleomorphic adenoma. One year later, she came with rapidly progressive swelling in bilateral cheeks and face. Intraoperatively, there was a large tumor in both maxillary sinuses with extensive local infiltration. Histologically, it was diagnosed as myoepithelial carcinoma. Carcinoma ex pleomorphic adenoma is usually a high grade malignancy. It occurs most commonly in parotid gland followed by submandibular glands, minor salivary glands and occasionally in sublingual gland. To the best of our knowledge, this is the first case of myoepithelial carcinoma arising in a recurrent pleomorphic adenoma in the maxillary sinus.

  6. An Aberrant Artery Arising From Common Hepatic Artery

    Directory of Open Access Journals (Sweden)

    Surekha D. Jadhav

    2015-01-01

    Full Text Available Common hepatic artery is the branch of celiac trunk which is chief artery of the foregut. Branches of celiac trunk supply the gastrointestinal tract and its associated glands which are derived from foregut. Anatomy and variations of hepatic arterial system have become increasingly important due to increasing number of laparoscopic procedures, oncologic surgical interventions, and organ transplant cases. This case report describes a rare anatomical variation of an aberrant artery arising from common hepatic artery before the origin of gastroduodenal artery and proper hepatic artery.The aberrant artery traversed inferiorly and behind the body of the pancreas which divided into a right and left branches. The right branch ran behind the neck of the pancreas and it ended after giving few branches to head and body of pancreas. However, the left branch gave off branches to the proximal part of the jejunum. The presence of a branch arising directly from the common hepatic artery supplying the pancreas and jejunum is uncommon. Knowledge of such a rare variation is important not only for surgeons but also interventional radiologists and those studying anatomy

  7. Poorly differentiated squamous cell carcinoma arising in tattooed skin.

    Science.gov (United States)

    Sarma, Deba P; Dentlinger, Renee B; Forystek, Amanda M; Stevens, Todd; Huerter, Christopher

    2010-01-01

    Introduction. Tattoos have increasingly become accepted by mainstream Western society. As a result, the incidence of tattoo-associated dermatoses is on the rise. The presence of a poorly differentiated squamous cell carcinoma in an old tattooed skin is of interest as it has not been previously documented. Case Presentation. A 79-year-old white homeless man of European descent presented to the dermatology clinic with a painless raised nodule on his left forearm arising in a tattooed area. A biopsy of the lesion revealed a poorly differentiated squamous cell carcinoma infiltrating into a tattoo. The lesion was completely excised and the patient remains disease-free one year later. Conclusion. All previous reports of squamous cell carcinomas arising in tattoos have been well-differentiated low-grade type or keratoacanthoma-type and are considered to be coincidental rather than related to any carcinogenic effect of the tattoo pigments. Tattoo-associated poorly differentiated invasive carcinoma appears to be extremely rare.

  8. Secondary osteosarcoma arising after treatment for childhood hematologic malignancies

    Science.gov (United States)

    Okada, Atsushi; Hosaka, Masami; Watanuki, Munenori; Itoi, Eiji

    2009-01-01

    Secondary osteosarcoma arising after the treatment of hematologic malignancies other than Hodgkin's lymphoma is rare. We report two cases of secondary osteosarcoma arising after treatment for childhood hematologic malignancies (non-Hodgkin's lymphoma and lymphoblastic leukemia). A 10-year-old boy, at the age of 3, was diagnosed with non-Hodgkin's lymphoma. He received chemotherapy, radiation, and bone-marrow transplantation and then was in complete remission. At 6 years, he complained of increasing pain of the right thigh and was diagnosed with osteoblastic osteosarcoma. A 26-year-old man, at the age of 6, was diagnosed as having acute lymphoblastic leukemia (ALL). He received chemotherapy, radiation, and peripheral blood stem cell transplantation (PBSCT). At 11 years after PBSCT, he visited with the complaint of left lumbar swelling. He was diagnosed with chondroblastic osteosarcoma. In both cases alkaline phosphatase (ALP) had already increased prior to the onset of the symptom. We should rule out secondary osteosarcoma at the abnormal elevation of ALP during clinical follow-up of patients after treatment of childhood hematologic malignancies. PMID:19961270

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

    Directory of Open Access Journals (Sweden)

    Tiffany J. Pan

    2015-01-01

    Full Text Available 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.

  10. Squamous Cell Carcinoma Arising in a Mature Cystic Teratoma

    Directory of Open Access Journals (Sweden)

    Suna Avcı

    2012-01-01

    Full Text Available Introduction. Malignant transformation in a mature cystic teratoma of the ovary is a rare complication. Squamous cell carcinoma is the most common transformation. We describe a new case of squamous cell carcinoma arising in a mature cystic teratoma. Case Report. A premenopausal 52-year-old female patient is diagnosed with vaginal bleeding. According to examination made on the women and the pelvic scanning, 7 cm mass is found on the right adnexa of the patient. Total abdominal hysterectomy, bilateral salpingo-oophorectomy, omentectomy, pelvic lymph node dissection, and debulking were the treatments completed on the patient. According to histopathological diagnosis, squamous cell carcinoma arising in a mature cystic teratoma is diagnosed as a reason for the mass in the right adnexa of the patient. Conclusion. The prognosis of the malign transformation of MCT depends on surgery stage; however it is extremely poor. The patient should receive chemotherapy regardless of stage. We have decided to administer second cycle carboplatin and paclitaxel treatments on the patient.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yamazaki, Kazutoshi, E-mail: kyamazak@kansai-u.ac.jp [Kansai University, Department of Mathematics, Faculty of Engineering Science (Japan)

    2015-08-15

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

  13. Fluctuation scaling in the visual cortex at threshold

    Science.gov (United States)

    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.

    Science.gov (United States)

    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. Rejection Thresholds in Chocolate Milk: Evidence for Segmentation

    Science.gov (United States)

    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

  16. Orientability thresholds for random hypergraphs

    CERN Document Server

    Gao, Pu

    2010-01-01

    Let $h>w>0$ be two fixed integers. Let $\\orH$ be a random hypergraph whose hyperedges are all of cardinality $h$. To {\\em $w$-orient} a hyperedge, we assign exactly $w$ of its vertices positive signs with respect to the hyperedge, and the rest negative. A $(w,k)$-orientation of $\\orH$ consists of a $w$-orientation of all hyperedges of $\\orH$, such that each vertex receives at most $k$ positive signs from its incident hyperedges. When $k$ is large enough, we determine the threshold of the existence of a $(w,k)$-orientation of a random hypergraph. The $(w,k)$-orientation of hypergraphs is strongly related to a general version of the off-line load balancing problem. The graph case, when $h=2$ and $w=1$, was solved recently by Cain, Sanders and Wormald and independently by Fernholz and Ramachandran, which settled a conjecture of Karp and Saks.

  17. Connectivity threshold for Bluetooth graphs

    CERN Document Server

    Broutin, Nicolas; Fraiman, Nicolas; Lugosi, Gábor

    2011-01-01

    We study the connectivity properties of random Bluetooth graphs that model certain "ad hoc" wireless networks. The graphs are obtained as "irrigation subgraphs" of the well-known random geometric graph model. There are two parameters that control the model: the radius $r$ that determines the "visible neighbors" of each node and the number of edges $c$ that each node is allowed to send to these. The randomness comes from the underlying distribution of data points in space and from the choices of each vertex. We prove that no connectivity can take place with high probability for a range of parameters $r, c$ and completely characterize the connectivity threshold (in $c$) for values of $r$ close the critical value for connectivity in the underlying random geometric graph.

  18. A RARE CASE REPORT OF SQUAMOUS CELL CARCINOMA OF URETHRA ARISING FROM SUBSTITUTED PENILE SKIN FLAP WITH BALANITIS XEROTICA OBLITERANS

    OpenAIRE

    2016-01-01

    A 44-year-old male presented with ulcerative growth over dorsal penile shaft along with multiple urethrocutaneous fistula. A total penectomy, scrotal excision and perineal urethrostomy were done. Past history of treatment for penile urethral stricture due to Balanitis Xerotica Obliterans (BXO) by substitution urethroplasty using pedicled preputial penile skin flap five years back. On gross as well as histopathological examination, the tumour was found to be arising from the skin ...

  19. Sesame allergy threshold dose distribution.

    Science.gov (United States)

    Dano, D; Remington, B C; Astier, C; Baumert, J L; Kruizinga, A G; Bihain, B E; Taylor, S L; Kanny, G

    2015-09-01

    Sesame is a relevant food allergen in France. Compared to other allergens there is a lack of food challenge data and more data could help sesame allergy risk management. The aim of this study is to collect more sesame challenge data and investigate the most efficient food challenge method for future studies. Records of patients at University Hospital in Nancy (France) with objective symptoms to sesame challenges were collected and combined with previously published data. An estimation of the sesame allergy population threshold was calculated based on individual NOAELs and LOAELs. Clinical dosing schemes at Nancy were investigated to see if the optimal protocol for sesame is currently used. Fourteen patients (10 M/4 F, 22 ± 14.85 years old) with objective symptoms were added to previously published data making a total of 35 sesame allergic patients. The most sensitive patient reacted to the first dose at challenge of 1.02 mg sesame protein. The ED05 ranges between 1.2 and 4.0 mg of sesame protein (Log-Normal, Log-Logistic, and Weibull models) and the ED10 between 4.2 and 6.2 mg. The optimal food challenge dosing scheme for sesame follows semi-log dose increases from 0.3 to 3000 mg protein. This article provides a valuable update to the existing clinical literature regarding sesame NOAELs and LOAELs. Establishment of a population threshold for sesame could help in increasing the credibility of precautionary labelling and decrease the costs associated with unexpected allergic reactions. Also, the use of an optimal dosing scheme would decrease time spent on diagnostic and thereafter on the economic burden of sesame allergy diagnosis. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Optimal control of switched systems arising in fermentation processes

    CERN Document Server

    Liu, Chongyang

    2014-01-01

    The book presents, in a systematic manner, the optimal controls under different mathematical models in fermentation processes. Variant mathematical models – i.e., those for multistage systems; switched autonomous systems; time-dependent and state-dependent switched systems; multistage time-delay systems and switched time-delay systems – for fed-batch fermentation processes are proposed and the theories and algorithms of their optimal control problems are studied and discussed. By putting forward novel methods and innovative tools, the book provides a state-of-the-art and comprehensive systematic treatment of optimal control problems arising in fermentation processes. It not only develops nonlinear dynamical system, optimal control theory and optimization algorithms, but can also help to increase productivity and provide valuable reference material on commercial fermentation processes.

  1. Sphenoid esthesioneuroblastoma arising from the hindmost olfactory filament.

    Science.gov (United States)

    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.

  2. Multicentric glioblastoma arising in two unusual sites: cerebellum and thalamus

    Directory of Open Access Journals (Sweden)

    Eduardo Cambruzzi

    2013-04-01

    Full Text Available Multicentric glioblastomas (MGBM arising in infra/supratentorial regions are uncommon lesions. The authors report a case of MGBM in a 61 year-old female patient, who presented a sudden onset of left hemiplegia. The magnetic resonance imaging (MRI showed two expansive large lesions affecting cerebellum and thalamus, with strong contrast enhancement. The patient underwent resection of the cerebellar lesion. Microscopy revealed a high grade glial neoplasm exhibiting high mitotic index, areas of necrosis and microvascular proliferation. The neoplastic cells showed positive immunoexpression for glial fibrillary acidic protein (GFAP. The morphological findings were consistent with glioblastoma (GBM. The patient was referred to radiotherapy, with discrete signs of tumor regression after a 60-day clinical follow-up.

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

    Energy Technology Data Exchange (ETDEWEB)

    Terman, D., E-mail: terman@math.ohio-state.edu [Department of Mathematics, The Ohio State University, Columbus, Ohio 43210 (United States); Rubin, J. E., E-mail: jonrubin@pitt.edu [Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Diekman, C. O., E-mail: diekman@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)

    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.

  4. Clear Cell Adenocarcinoma Arising from Abdominal Wall Endometriosis

    Directory of Open Access Journals (Sweden)

    Thouraya Achach

    2008-01-01

    Full Text Available Endometriosis is a frequent benign disorder. Malignancy arising in extraovarian endometriosis is a rare event. A 49-year-old woman is presented with a large painful abdominal wall mass. She underwent a myomectomy, 20 years before, for uterus leiomyoma. Computed tomography suggested that this was a desmoid tumor and she underwent surgery. Histological examination showed a clear cell adenocarcinoma associated with endometriosis foci. Pelvic ultrasound, computed tomography, and endometrial curettage did not show any malignancy or endometriosis in the uterus and ovaries. Adjuvant chemotherapy was recommended, but the patient was lost to follow up. Six months later, she returned with a recurrence of the abdominal wall mass. She was given chemotherapy and then she was reoperated.

  5. Extravasation Mucocele Arising from a Lingual Thyroglossal Duct Remnant

    Directory of Open Access Journals (Sweden)

    Mitsuhiko Nakahira

    2015-01-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2016-07-01

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

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Moldovanu, Simona [Faculty of Sciences and Environment, Department of Chemistry, Physics and Environment, Dunărea de Jos University of Galaţi, 47 Domnească St., 800008, Romania, Phone: +40 236 460 780 (Romania); Dumitru Moţoc High School, 15 Milcov St., 800509, Galaţi (Romania); Obreja, Cristian; Moraru, Luminita, E-mail: luminita.moraru@ugal.ro [Faculty of Sciences and Environment, Department of Chemistry, Physics and Environment, Dunărea de Jos University of Galaţi, 47 Domnească St., 800008, Romania, Phone: +40 236 460 780 (Romania)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Jemcov, A.; Matovic, M.D. [Queen`s Univ., Kingston, Ontario (Canada)

    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.

  10. On Dynamic Adjustment of Capital Structure in Listed Companies in China Based on a Multiple Threshold Model%基于多重门限模型的我国上市公司资本结构动态调整研究

    Institute of Scientific and Technical Information of China (English)

    段军山; 宋贺

    2012-01-01

    From the perspective of dynamic trade-off theory, this paper employs a multiple threshold panel model to study the dynamic adjustment path of the capital structure of A-share listed companies in Shanghai Stock Exchange and Shenzhen Stock Exchange in China from 2000 to 2009. The result shows that the adjustment of capital structure is characterized by a- symmetry which means that as the debt ratio rises, the effect of operating performance on the adjustment speed gradually weakens. The adjustment speed in state-owned companies is lower, indicating that soft budget con- straints and a lack of supervision in state-owned enterprises are in urgent need of solution in the reform of state-owned enterprises in China. And ow- ing to the effect of institutional adjustment speed, auditor sign transmission effect can not exert an obvious function in the adjustment of corporate capital structure.%文章以动态权衡理论为视角,采用多重门限面板模型,研究了2000—2009年我国沪深A股上市公司资本结构的动态调整路径。研究结果表明,我国上市公司资本结构的调整存在非对称现象,即随着负债率的提高,经营绩效对调整速度的影响逐步减弱。国有控股公司的调整速度较慢,表明国有企业的预算软约束和监管缺失等是国有企业亟须解决的问题;由于制度调整成本的影响,审计师信号传递效应未能在公司资本结构调整中发挥明显作用。

  11. Multiple Pregnancy

    Science.gov (United States)

    ... Education & Events Advocacy For Patients About ACOG Multiple Pregnancy Home For Patients Search FAQs Multiple Pregnancy Page ... Multiple Pregnancy FAQ188, July 2015 PDF Format Multiple Pregnancy Pregnancy How does multiple pregnancy occur? What are ...

  12. Dark Matter Searches for Monoenergetic Neutrinos Arising from Stopped Meson Decay in the Sun

    CERN Document Server

    Rott, Carsten; Kumar, Jason; Yaylali, David

    2015-01-01

    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...

  13. Melanotic schwannoma arising in association with nevus of Ota: 2 cases suggesting a shared mechanism.

    Science.gov (United States)

    Trufant, Joshua W; Brenn, Thomas; Fletcher, Christopher D M; Virata, Andrew R; Cook, Deborah L; Bosenberg, Marcus W

    2009-12-01

    Melanotic schwannoma is a rare markedly pigmented peripheral nerve sheath tumor comprising cells with prominent melanization and schwannian features. The psammomatous variety is associated with Carney complex, a multiple neoplasia syndrome with spotty skin pigmentation. We present the first 2 reported cases of melanotic schwannoma arising in patients with a history of nevus of Ota, a rare dermal melanosis believed to represent a failure of melanocyte migration to the epidermis during embryogenesis. Case 1 involves a 40-year-old woman with a 1.8-cm, deeply pigmented, trigeminal nerve mass and pigmentation of the maxillary sinus mucosa and bone. Case 2 involves a 53-year-old woman with a 1.5-cm mass adjacent to the clavicle. Microscopically, both masses consist of partially encapsulated epithelioid and spindle cells with abundant melanin pigment, arising in association with peripheral nerves. Morphological, immunohistochemical, and ultrastructural features support a diagnosis of melanotic schwannoma. No psammoma bodies are noted, and neither patient exhibits any additional features of Carney complex. Melanotic schwannoma is most often benign but has been associated with malignant behavior in some cases. Distinguishing this nerve sheath tumor from malignant melanoma can be difficult but is of great clinical importance due to differences in prognosis and treatment.

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

    Energy Technology Data Exchange (ETDEWEB)

    Rott, Carsten; In, Seongjin [Department of Physics, Sungkyunkwan University,Suwon, 440-746 (Korea, Republic of); Kumar, Jason [Department of Physics & Astronomy, University of Hawai’i,Honolulu, HI, 96822 (United States); Yaylali, David [Department of Physics, University of Arizona,Tucson, AZ, 85721 (United States); Department of Physics, University of Maryland,College Park, MD, 20742 (United States)

    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.

  15. Threshold-dominated regulation hides genetic variation in gene expression networks

    Directory of Open Access Journals (Sweden)

    Plahte Erik

    2007-12-01

    Full Text Available Abstract Background In dynamical models with feedback and sigmoidal response functions, some or all variables have thresholds around which they regulate themselves or other variables. A mathematical analysis has shown that when the dose-response functions approach binary or on/off responses, any variable with an equilibrium value close to one of its thresholds is very robust to parameter perturbations of a homeostatic state. We denote this threshold robustness. To check the empirical relevance of this phenomenon with response function steepnesses ranging from a near on/off response down to Michaelis-Menten conditions, we have performed a simulation study to investigate the degree of threshold robustness in models for a three-gene system with one downstream gene, using several logical input gates, but excluding models with positive feedback to avoid multistationarity. Varying parameter values representing functional genetic variation, we have analysed the coefficient of variation (CV of the gene product concentrations in the stable state for the regulating genes in absolute terms and compared to the CV for the unregulating downstream gene. The sigmoidal or binary dose-response functions in these models can be considered as phenomenological models of the aggregated effects on protein or mRNA expression rates of all cellular reactions involved in gene expression. Results For all the models, threshold robustness increases with increasing response steepness. The CVs of the regulating genes are significantly smaller than for the unregulating gene, in particular for steep responses. The effect becomes less prominent as steepnesses approach Michaelis-Menten conditions. If the parameter perturbation shifts the equilibrium value too far away from threshold, the gene product is no longer an effective regulator and robustness is lost. Threshold robustness arises when a variable is an active regulator around its threshold, and this function is maintained by

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

    Science.gov (United States)

    Zhang, Jianlei; Zhang, Chunyan; Cao, Ming

    2015-03-13

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

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

    Science.gov (United States)

    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'.

  18. Pattern Completion in Symmetric Threshold-Linear Networks.

    Science.gov (United States)

    Curto, Carina; Morrison, Katherine

    2016-12-01

    Threshold-linear networks are a common class of firing rate models that describe recurrent interactions among neurons. Unlike their linear counterparts, these networks generically possess multiple stable fixed points (steady states), making them viable candidates for memory encoding and retrieval. In this work, we characterize stable fixed points of general threshold-linear networks with constant external drive and discover constraints on the coexistence of fixed points involving different subsets of active neurons. In the case of symmetric networks, we prove the following antichain property: if a set of neurons [Formula: see text] is the support of a stable fixed point, then no proper subset or superset of [Formula: see text] can support a stable fixed point. Symmetric threshold-linear networks thus appear to be well suited for pattern completion, since the dynamics are guaranteed not to get stuck in a subset or superset of a stored pattern. We also show that for any graph G, we can construct a network whose stable fixed points correspond precisely to the maximal cliques of G. As an application, we design network decoders for place field codes and demonstrate their efficacy for error correction and pattern completion. The proofs of our main results build on the theory of permitted sets in threshold-linear networks, including recently developed connections to classical distance geometry.

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

    Science.gov (United States)

    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."

  20. Multiple sclerosis; Multiple Sklerose

    Energy Technology Data Exchange (ETDEWEB)

    Grunwald, I.Q.; Kuehn, A.L.; Backens, M.; Papanagiotou, P. [Universitaet des Saarlandes, Abteilung fuer Diagnostische und Interventionelle Neuroradiologie, Radiologische Klinik, Homburg/Saar (Germany); Shariat, K. [Universitaet des Saarlandes, Klinik fuer Neurochirurgie, Homburg/Saar (Germany); Kostopoulos, P. [Universitaet des Saarlandes, Klinik fuer Neurologie, Homburg/Saar (Germany)

    2008-06-15

    Multiple sclerosis is the most common chronic inflammatory disease of myelin with interspersed lesions in the white matter of the central nervous system. Magnetic resonance imaging (MRI) plays a key role in the diagnosis and monitoring of white matter diseases. This article focuses on key findings in multiple sclerosis as detected by MRI. (orig.) [German] Die Multiple Sklerose (MS) ist die haeufigste chronisch-entzuendliche Erkrankung des Myelins mit eingesprengten Laesionen im Bereich der weissen Substanz des zentralen Nervensystems. Die Magnetresonanztomographie (MRT) hat bei der Diagnosestellung und Verlaufskontrolle eine Schluesselrolle. Dieser Artikel befasst sich mit Hauptcharakteristika der MR-Bildbebung. (orig.)

  1. Image Segmentation by Using Threshold Techniques

    CERN Document Server

    Al-amri, Salem Saleh; D., Khamitkar S

    2010-01-01

    This paper attempts to undertake the study of segmentation image techniques by using five threshold methods as Mean method, P-tile method, Histogram Dependent Technique (HDT), Edge Maximization Technique (EMT) and visual Technique and they are compared with one another so as to choose the best technique for threshold segmentation techniques image. These techniques applied on three satellite images to choose base guesses for threshold segmentation image.

  2. Finance, growth and threshold effects

    Directory of Open Access Journals (Sweden)

    Allegret Jean-Pierre

    2012-01-01

    Full Text Available In this paper, we test the existence of financial development threshold effects, firstly, between financial development and long-term growth, and, secondly, between financial development and long-term GDP. We also ask whether such effects may explain the link financial development - convergence/ divergence to the advanced countries’ growth. Our work builds on that of Aghion, Howitt, and Mayer-Foulkes (2004. It differs from previous work about assumptions and methodology. Estimates are performed with GMM dynamic panel data techniques for 112 emerging and developing countries from 1975 to 2007. The results show a positive but vanishing effect of financial development on steady-state GDP, from a critical (an average level of financial development. They do not validate, however, the assumption that the marginal impact of financial development on the steady-state growth rate is more favorable than the degree of financial development is low. We support only partially the role that the financial development could play in the acceleration of the convergence of emerging and developing economies towards the world frontier growth.

  3. Threshold electric field in unconventional density waves

    Science.gov (United States)

    Dóra, Balázs; Virosztek, Attila; Maki, Kazumi

    2001-07-01

    As it is well known most charge-density waves (CDW's) and spin-density waves exhibit nonlinear transport with well-defined threshold electric field ET. Here we study theoretically the threshold electric field of unconventional density waves. We find that the threshold field increases monotonically with temperature without divergent behavior at Tc, unlike the one in conventional CDW. The present result in the three-dimensional weak pinning limit appears to describe rather well the threshold electric field observed recently in the low-temperature phase of α-(BEDT-TTF)2KHg(SCN)4.

  4. Enhance Confidentiality of Threshold Signature for MANET

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; XIONG Zhongwei

    2006-01-01

    The participating wireless mobile node that mobile ad hoc network (MANET) communications need to forward may be malicious. That means not only adversary might be able to acquire some sensitive information of the threshold signatures from the compromised node, but also the partial signatures may be fabricated by malicious node, the advantages of threshold signatures would disappear. Signing and encrypting the sensitive information of the threshold signatures, and only the specified receiver can recover it, which will improve the confidentiality of threshold signatures. The security analysis shows the method is suitable for the secure characteristic of MANET that has the malicious nodes, and the message transmission is secure can against the attack.

  5. Giant solitary fibrous tumor arising from greater omentum

    Institute of Scientific and Technical Information of China (English)

    Liang Zong; Ping Chen; Guang-Yao Wang; Qun-Shan Zhu

    2012-01-01

    Extrathoracic solitary fibrous tumors (SFTs) have been described at almost every anatomic location of human body,but reports of SFT in the abdominal cavity are rare.We herein present a rare case of SFT originating from greater omentum.Computed tomography revealed a 15.8 cm x 21.0 cm solid mass located at superior aspect of stomach.Open laparotomy confirmed its mesenchymal origin.Microscopically,its tissue was composed of non-organized and spindle-shaped cells exhibiting atypical nuclei,which were divided up by branching vessel and collagen bundles.Immunohistochemical staining showed that this tumor was negative for CD117,CD99,CD68,cytokeratin,calretinin,desmin,epithelial membrane antigen,F8 and S-100,but positive for CD34,bcl-2,α-smooth muscle actin and vimentin.The patient presented no evidence of recurrence during follow-up.SFT arising from abdominal cavity can be diagnosed by histological findings and immunohistochemical markers,especially for CD34 and bcl-2 positive cases.

  6. On Bounded Posets Arising from Quantum Mechanical Measurements

    Science.gov (United States)

    Dorninger, Dietmar; Länger, Helmut

    2016-10-01

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

  7. Sparse gamma rhythms arising through clustering in adapting neuronal networks.

    Directory of Open Access Journals (Sweden)

    Zachary P Kilpatrick

    2011-11-01

    Full Text Available 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.

  8. Proprioceptive recalibration arises slowly compared to reach adaptation.

    Science.gov (United States)

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

    2016-08-01

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

  9. Primary abdominal wall clear cell carcinoma arising from incisional endometriosis

    Institute of Scientific and Technical Information of China (English)

    Burcu Gundogdu; Isin Ureyen; Gunsu Kimyon; Hakan Turan; Nurettin Boran; Gokhan Tulunay; Dilek Bulbul; Taner Turan; M Faruk Kose

    2013-01-01

    A 49 year-old patient with the complaint of a mass located in the caesarean scar was admitted. There was a fixed mass 30í30 mm in diameter with regular contour located at the right corner of the pfannenstiel incision. Computed tomography revealed a (40í50í50) mm solid mass lesion with margins that cannot be distinguished from the uterus, bladder and small intestines and a heterogeneous mass lesion (50í45í55) mm in diameter, located in the right side of the anterior abdominal wall. Cytoreductive surgery including total abdominal hysterectomy and bilateral salpingo-oophorectomy was performed. Final pathology was clear cell carcinoma. Clear cell carcinoma arising from an extraovarian endometriotic focus was diagnosed and the patient received 6 cycles paclitaxel-carboplatin chemotherapy as adjuvant treatment. The patient who was lost to follow-up applied to our clinic 2 years after surgery with a recurrent mass in the left inguinal region. After 3 cycles of chemotherapy, the patient's tumoral mass in the left inguinal region was excised. The result of the pathology was carcinoma metastasis. It is decided that the following treatment of the patient should be palliative radiation therapy. The patient who underwent palliative radiation therapy died of disease after 4 months of the second operation.

  10. Coalescent processes arising in a study of diffusive clustering

    CERN Document Server

    Greven, Andreas; Winter, Anita

    2007-01-01

    This paper studies spatial coalescents on $\\Z^2$. In our setting, the partition elements are located at the sites of $\\Z^2$ and undergo local delayed coalescence and migration. The system starts in either locally finite configurations or in configurations containing countably many partition elements per site. Our goal is to determine the longtime behavior with an initial population of countably many individuals per site restricted to a box $[-t^{\\alpha/2}, t^{\\alpha/2}]^2 \\cap \\Z^2$ and observed at time $t^\\beta$ with $1 \\geq \\beta \\geq \\alpha\\ge 0$. We study both asymptotics, as $t\\to\\infty$, for a fixed value of $\\alpha$ as the parameter $\\beta\\in[\\alpha,1]$ varies, and for a fixed $\\beta=1$, as the parameter $\\alpha\\in [0,1]$ varies. A new random object, the so-called {\\em coalescent with rebirth}, is constructed and shown to arise in the limit. In view of future applications we introduce the spatial coalescent with rebirth and study its longtime asymptotics as well. The present paper is the basis for fort...

  11. Novel ethical dilemmas arising in geriatric clinical practice.

    Science.gov (United States)

    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.

  12. Esophageal Adenocarcinoma Arising from Barrett's Epithelium in Taiwan

    Directory of Open Access Journals (Sweden)

    Chia-Hung Tu

    2007-08-01

    Full Text Available The prevalence of Barrett's esophagus (BE in Eastern countries is rising to match the prevalence in the West. However, a corresponding trend of BE-associated adenocarcinoma has yet to be observed in Asia. Historically, adenocarcinoma complicating BE has been considered a rare event in Taiwan. In the present report, we collected three Taiwanese cases of esophageal adenocarcinoma arising from BE. The first case was a 37-year-old man with an advanced cancer that developed on pre-existing BE after a 3-year interval without endoscopic surveillance. The second case was a 63-year-old man who presented with odynophagia and was found to have an ulcerative tumor centered on the characteristic Barrett's mucosa. The final case was a 44-year-old man who presented with gradual-onset dysphagia and weight loss, without typical reflux symptom. Our report emphasizes the need for an updated epidemiologic study to determine the incidence of BE-associated adenocarcinoma in Taiwan.

  13. A closest vector problem arising in radiation therapy planning

    CERN Document Server

    Engelbeen, Celine; Kiesel, Antje

    2009-01-01

    In this paper we consider the problem of finding a vector that can be written as a nonnegative, integer and linear combination of given 0-1 vectors, the generators, such that the l_1-distance between this vector and a given target vector is minimized. We prove that this closest vector problem is NP-hard to approximate within an additive error of (ln 2 - eps) d for all epsilon > 0, where d is the dimension of the ambient vector space. We show that the problem can be approximated within an additive error of (e/4+ln 2/2) d^{3/2} in polynomial time, by rounding an optimal solution of a natural LP relaxation for the problem. We also give a proof that in the particular case where the vectors satisfy the consecutive ones property, the problem can be formulated as a min-cost flow problem, hence can be solved in polynomial time. The closest vector problem arises in the elaboration of radiation therapy plans. In this context, the target is a nonnegative integer matrix and the generators are certain binary matrices whos...

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Woo, C.H. [Hong Kong Polytechnic Univ., Kowloon (Hong Kong); Garner, F.A. [Pacific Northwest National Lab., Richland, WA (United States)

    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.

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

    Science.gov (United States)

    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.

  17. Primary Extraskeletal Mesenchymal Chondrosarcoma Arising from the Pancreas

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Bae Geun; Han, Yoon Hee; Lee, Byung Hoon; Kim, Su Young; Hwang, Yoon Joon; Seo, Jung Wook; Kim, Yong Hoon; Cha, Soon Joo; Hur, Gham; Joo, Mee [Inje University, School of Medicine, Goyang (Korea, Republic of)

    2007-12-15

    The CT scans showed a heterogeneously enhancing necrotic mass with numerous areas of coarse calcification, and this was located in the left side of the retroperitoneal space and involved the body and tail of the pancreas. Portal venography via the celiac axis also showed invasion of the splenic vein. It represents approximately 1% of all chondrosarcomas and it carries a poor prognosis. It can occur in extraskeletal locations and mainly in the soft tissues of the orbit, the cranial and spinal meningeal coverings and the lower limbs. To the best of our knowledge, there has been no reported case of primary extraskeletal mesenchymal chondrosarcoma of the pancreas. Only two instances of metastatic chondrosarcomas in the pancreas have been reported in the literature. We report here on a case of primary mesenchymal chondrosarcoma arising from the pancreas in a 41-year-old man. In summary, we present here a case of primary extraskeletal mesenchymal chondrosarcoma that arose from the pancreas. Radiologically, it manifested as a necrotic soft tissue mass with chondroid calcifications.

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

    Directory of Open Access Journals (Sweden)

    Hsu Ying-Che

    2006-06-01

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

  19. Squamous cell carcinoma arising from primary retroperitoneal mature teratoma.

    Science.gov (United States)

    Joseph, Leena D; Devi, M Kanmani; Sundaram, Sandhya; Rajendiran, S

    2007-05-01

    A 65 year old postmenopausal female presented with left sided abdominal pain. Sonogram revealed an intra-abdominal 7.4 x 5.7 cm heterogenous mass. On laparotomy, approximately 10 X 10 cm mesenteric mass was seen adherent to the descending colon. Multiple omental tumor deposits were also noted. Gross examination showed solid and cystic tumor with sebaceous material admixed with hair. Histopathology showed mature cystic teratoma with a spectrum of well to poorly differentiated squamous cell carcinoma with omental metastasis.

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

    Directory of Open Access Journals (Sweden)

    Nandi Soumyadeep

    2007-03-01

    Full Text Available Abstract 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

  1. Performance Assessment of Hydrological Models Considering Acceptable Forecast Error Threshold

    Directory of Open Access Journals (Sweden)

    Qianjin Dong

    2015-11-01

    Full Text Available It is essential to consider the acceptable threshold in the assessment of a hydrological model because of the scarcity of research in the hydrology community and errors do not necessarily cause risk. Two forecast errors, including rainfall forecast error and peak flood forecast error, have been studied based on the reliability theory. The first order second moment (FOSM and bound methods are used to identify the reliability. Through the case study of the Dahuofang (DHF Reservoir, it is shown that the correlation between these two errors has great influence on the reliability index of hydrological model. In particular, the reliability index of the DHF hydrological model decreases with the increasing correlation. Based on the reliability theory, the proposed performance evaluation framework incorporating the acceptable forecast error threshold and correlation among the multiple errors can be used to evaluate the performance of a hydrological model and to quantify the uncertainties of a hydrological model output.

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

    Science.gov (United States)

    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. Amplification, Saturation, and Q Thresholds for Runaway Growth of Self-Gravitating Structures in Models of Magnetized Galactic Gas Disks

    CERN Document Server

    Kim, W T; Kim, Woong-Tae; Ostriker, Eve C.

    2001-01-01

    We investigate the susceptibility of gaseous, magnetized galactic disks to formation of self-gravitating condensations using two-dimensional, local models. We focus on two issues: (1) determining the threshold condition for gravitational runaway, taking into account nonlinear effects, and (2) distinguishing the magneto-Jeans instability (MJI) that arises under inner-galaxy rotation curves from the modified swing amplification (MSA) that arises under outer-galaxy rotation curves. For axisymmetric density fluctuations, instability is known to require a Toomre parameter Q<1. For nonaxisymmetric fluctuations, any nonzero shear $q \\equiv -d\\ln \\Omega /d \\ln R$ winds up wavefronts such that in linear theory amplification saturates. Any Q threshold for nonaxisymmetric gravitational runaway must originate from nonlinear effects. We use numerical magnetohydrodynamic simulations to demonstrate the anticipated threshold phenomenon, to analyze the nonlinear processes involved, and to evaluate the critical value $Q_c$ ...

  4. A Singular Value Thresholding Algorithm for Matrix Completion

    CERN Document Server

    Cai, Jian-Feng; Shen, Zuowei

    2008-01-01

    This paper introduces a novel algorithm to approximate the matrix with minimum nuclear norm among all matrices obeying a set of convex constraints. This problem may be understood as the convex relaxation of a rank minimization problem, and arises in many important applications as in the task of recovering a large matrix from a small subset of its entries (the famous Netflix problem). Off-the-shelf algorithms such as interior point methods are not directly amenable to large problems of this kind with over a million unknown entries. This paper develops a simple first-order and easy-to-implement algorithm that is extremely efficient at addressing problems in which the optimal solution has low rank. The algorithm is iterative and produces a sequence of matrices (X^k, Y^k) and at each step, mainly performs a soft-thresholding operation on the singular values of the matrix Y^k. There are two remarkable features making this attractive for low-rank matrix completion problems. The first is that the soft-thresholding o...

  5. Qualia could arise from information processing in local cortical networks

    Directory of Open Access Journals (Sweden)

    Roger D Orpwood

    2013-03-01

    Full Text Available Re-entrant feedback, either within sensory cortex or arising from prefrontal areas, has been strongly linked to the emergence of consciousness, both in theoretical and experimental work. This idea, together with evidence for local micro-consciousness, suggests the generation of qualia could in some way result from local network activity under re-entrant activation. This paper explores the possibility by examining the processing of information by local cortical networks. It highlights the difference between the information structure (how the information is physically embodied, and the information message (what the information is about. It focuses on the network’s ability to recognise information structures amongst its inputs under conditions of extensive local feedback, and to then assign information messages to those structures. It is shown that if the re-entrant feedback enables the network to achieve an attractor state, then the message assigned in any given pass of information through the network is a representation of the message assigned in the previous pass-through of information. Based on this ability the paper argues that as information is repeatedly cycled through the network, the information message that is assigned evolves from a recognition of what the input structure is, to what it is like, to how it appears, to how it seems. It could enable individual networks to be the site of qualia generation. The paper goes on to show networks in cortical layers 2/3 and 5a have the connectivity required for the behaviour proposed, and reviews some evidence for a link between such local cortical cyclic activity and conscious percepts. It concludes with some predictions based on the theory discussed.

  6. Sewage sludge - arisings, composition, disposal capacities; Klaerschlamm - Mengen, Zusammensetzung, Entsorgungskapazitaeten

    Energy Technology Data Exchange (ETDEWEB)

    Faulstich, M.; Rabus, J. [Technische Univ. Muenchen, Garching (Germany). Lehrstuhl fuer Wasserguete- und Abfallwirtschaft; Urban, A.I.; Friedel, M. [Kassel Univ. (Gesamthochschule) (Germany). Fachgebiet Abfalltechnik

    1998-09-01

    One of the main disposal paths for sewage sludge in the past was landfilling. This option was severely restricted by the issue of the Technical Code on Household Waste in 1993. In its agricultural applications sewage sludge serves as a fertiliser and a soil improvement agent. Estimates on potential thermal treatment capacities have shown that there are enough public power plants to accommodate and provide thermal treatment for the total of sewage sludge arisings in Germany. As can be seen from the estimates presented in this paper, it would not even be necessary to restrict oneself to public power plant capacities. The paper points out possibilities of using plant capacities already existing in industrial firing plants and certain production sectors. It uses a comparison to show that sewage sludge would have to be dried in order to permit its thermal treatment in these private facilities. Aside from this, there are a number of new techniques entering the market which from the technical viewpoint also appear to be well suited for thermal sewage sludge treatment. [Deutsch] Ein wesentlicher Entsorgungsweg von Klaerschlamm war in der Vergangenheit die Verbringung auf eine Deponie. Diese Moeglichkeit ist durch die TA Siedlungsabfall von 1993 stark eingeschraenkt. Bei der landwirtschaftlichen Verwertung wird durch den Klaerschlamm eine Duengewirkung sowie eine Bodenverbesserung erreicht. Eine Abschaetzung der potentiellen thermischen Behandlungskapazitaeten zeigt, dass die gesamte bundesdeutsche Klaerschlammenge in oeffentlichen Kraftwerken unterzubringen und thermisch zu behandeln waere. Wie die hier dargestellten Abschaetzungen gezeigt haben, ist man durchaus nicht allein auf die Nutzung oeffentlicher Kraftwerkskapazitaeten angewiesen. Es wurden Moeglichkeiten zur Nutzung vorhandener Anlagenkapazitaeten in industriellen Feuerungsanlagen und in Produktionsbereichen aufgezeigt. Wie aus einem Vergleich erkennbar wird, ist allerdings eine Trocknung der Klaerschlaemme

  7. Obesity, the endocannabinoid system, and bias arising from pharmaceutical sponsorship.

    Directory of Open Access Journals (Sweden)

    John M McPartland

    Full Text Available 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.

  8. Urban surface water pollution problems arising from misconnections.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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

  10. Dracunculiasis eradication - Finishing the job before surprises arise

    Institute of Scientific and Technical Information of China (English)

    Benjamin Jelle Visser

    2012-01-01

    ABSTRACT Dracunculiasis(Guinea worm disease) is a preventable waterborne parasitic disease that affects the poorest people living in remote rural areas in sub-SaharanAfrican countries, who do not have access to safe drinking water.The Guinea Worm Eradication Program, a25-year old campaign to rid the world ofGuineaWorm disease has now reached its final stage accelerating to zero cases in all endemic countries.During the19th and20th centuries, dracunculiasis was common in much ofSouthernAsia and theAfrican continent.The overall number of cases has been reduced tremendously by≥99%, from the3.32 million cases estimated to have occurred in1986 inAfrica to only1797 cases reported in2010 reported in only five countries(Sudan,Mali,Ethiopia,Chad andGhana) andAsia 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,SouthSudan(comprising94% or1698 out of1797 of the cases reported world-wide in2010) andMali because of frequent movements of nomads in a vast area inside and outsideMali’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.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2016-03-01

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

  13. Detectability thresholds of general modular graphs

    CERN Document Server

    Kawamoto, Tatsuro

    2016-01-01

    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.

  14. Thresholding magnetic resonance images of human brain

    Institute of Scientific and Technical Information of China (English)

    Qing-mao HU; Wieslaw L NOWINSKI

    2005-01-01

    In this paper, methods are proposed and validated to determine low and high thresholds to segment out gray matter and white matter for MR images of different pulse sequences of human brain. First, a two-dimensional reference image is determined to represent the intensity characteristics of the original three-dimensional data. Then a region of interest of the reference image is determined where brain tissues are present. The non-supervised fuzzy c-means clustering is employed to determine: the threshold for obtaining head mask, the low threshold for T2-weighted and PD-weighted images, and the high threshold for T1-weighted, SPGR and FLAIR images. Supervised range-constrained thresholding is employed to determine the low threshold for T1-weighted, SPGR and FLAIR images. Thresholding based on pairs of boundary pixels is proposed to determine the high threshold for T2- and PD-weighted images. Quantification against public data sets with various noise and inhomogeneity levels shows that the proposed methods can yield segmentation robust to noise and intensity inhomogeneity. Qualitatively the proposed methods work well with real clinical data.

  15. Voting on Thresholds for Public Goods

    DEFF Research Database (Denmark)

    Rauchdobler, Julian; Sausgruber, Rupert; Tyran, Jean-Robert

    Introducing a threshold in the sense of a minimal project size transforms a public goods game with an inefficient equilibrium into a coordination game with a set of Pareto-superior equilibria. Thresholds may therefore improve efficiency in the voluntary provision of public goods. In our one...

  16. Thresholds for odor and nasal pungency.

    Science.gov (United States)

    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.

  17. Mesopic visual efficiency I: Detection threshold measurements

    NARCIS (Netherlands)

    Eloholma, M.; Ketomaki, J; Halonen, L.; Walkey, H.; Goodman, T.; Alferdinck, J.W.A.M.; Bodrogi, P.

    2007-01-01

    Achromatic thresholds are measured at three sites to investigate the effects of light spectrum on achromatic detection thresholds in the mesopic region. The results of measurements using quasi-monochromatic targets reveal spectral sensitivity functions with two or three peaks, a so-called ‘chromatic

  18. Applying Threshold Concepts to Finance Education

    Science.gov (United States)

    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. Threshold Concepts, Systems and Learning for Sustainability

    Science.gov (United States)

    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…

  20. Vector Broadcast Channels: Optimal Threshold Selection Problem

    CERN Document Server

    Samarasinghe, Tharaka; Evans, Jamie

    2011-01-01

    Threshold feedback policies are well known and provably rate-wise optimal selective feedback techniques for communication systems requiring partial channel state information (CSI). However, optimal selection of thresholds at mobile users to maximize information theoretic data rates subject to feedback constraints is an open problem. In this paper, we focus on the optimal threshold selection problem, and provide a solution for this problem for finite feedback systems. Rather surprisingly, we show that using the same threshold values at all mobile users is not always a rate-wise optimal feedback strategy, even for a system with identical users experiencing statistically the same channel conditions. By utilizing the theory of majorization, we identify an underlying Schur-concave structure in the rate function and obtain sufficient conditions for a homogenous threshold feedback policy to be optimal. Our results hold for most fading channel models, and we illustrate an application of our results to familiar Raylei...

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

    Science.gov (United States)

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

    2016-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.; Barua, A.; Zhou, M., E-mail: min.zhou@me.gatech.edu [The George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405 (United States); Horie, Y. [Air Force Research Lab, Munitions Directorate, 2306 Perimeter Road, Eglin AFB, Florida 32542 (United States)

    2014-05-07

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

  3. Red cell antibodies arising from solid organ transplants.

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

  5. Monocular and binocular depth discrimination thresholds.

    Science.gov (United States)

    Kaye, S B; Siddiqui, A; Ward, A; Noonan, C; Fisher, A C; Green, J R; Brown, M C; Wareing, P A; Watt, P

    1999-11-01

    Measurement of stereoacuity at varying distances, by real or simulated depth stereoacuity tests, is helpful in the evaluation of patients with binocular imbalance or strabismus. Although the cue of binocular disparity underpins stereoacuity tests, there may be variable amounts of other binocular and monocular cues inherent in a stereoacuity test. In such circumstances, a combined monocular and binocular threshold of depth discrimination may be measured--stereoacuity conventionally referring to the situation where binocular disparity giving rise to retinal disparity is the only cue present. A child-friendly variable distance stereoacuity test (VDS) was developed, with a method for determining the binocular depth threshold from the combined monocular and binocular threshold of depth of discrimination (CT). Subjects with normal binocular function, reduced binocular function, and apparently absent binocularity were included. To measure the threshold of depth discrimination, subjects were required by means of a hand control to align two electronically controlled spheres at viewing distances of 1, 3, and 6m. Stereoacuity was also measured using the TNO, Frisby, and Titmus stereoacuity tests. BTs were calculated according to the function BT= arctan (1/tan alphaC - 1/tan alphaM)(-1), where alphaC and alphaM are the angles subtended at the nodal points by objects situated at the monocular threshold (alphaM) and the combined monocular-binocular threshold (alphaC) of discrimination. In subjects with good binocularity, BTs were similar to their combined thresholds, whereas subjects with reduced and apparently absent binocularity had binocular thresholds 4 and 10 times higher than their combined thresholds (CT). The VDS binocular thresholds showed significantly higher correlation and agreement with the TNO test and the binocular thresholds of the Frisby and Titmus tests, than the corresponding combined thresholds (p = 0.0019). The VDS was found to be an easy to use real depth

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

    Science.gov (United States)

    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.

  7. Facility for studying spin dependence in pion production near threshold

    CERN Document Server

    Rinckel, T; Meyer, H O; Balewski, J T; Doskow, J; Pollock, R E; Von Przewoski, B; Sperisen, F; Daehnick, W W; Flammang, R W; Saha, S K; Haeberli, W; Lorentz, B; Rathmann, F; Schwartz, B; Wise, T; Pancella, P V

    2000-01-01

    We describe an experimental setup for the measurement of polarization observables in pion production near threshold. Experiments carried out with this facility use a polarized proton beam in the Indiana University Cooler storage ring, and an internal, polarized hydrogen target. The detector system measures energy, direction and velocity of multiple outgoing charged particles that are within a forward cone of about 32 deg. opening angle. An array of scintillators also allows the detection of neutrons. In addition to the technical details of the apparatus, we describe the procedure for data acquisition, as well as some aspects of the analysis.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.I.; Yoon, P.H.; Ryu, Y.H.; Jeon, P.; Hwang, G.J. [Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1998-08-01

    We reviewed the MRI findings of germinomas originating from the basal ganglia, thalamus or deep white matter in 13 patients with 14 germinomas, excluding those in the suprasellar or pineal regions. Ten cases were confirmed as germinomas by stereotaxic biopsy, three by partial and one by total removal of the tumour. Analysis was focussed on the location and the signal characteristic of the tumour, haemorrhage, cysts within the tumour and any other associated findings. Thirteen of the tumours were in the basal ganglia and one in the thalamus. Haemorrhage was observed in seven patients, while twelve showed multiple cysts. Associated ipsilateral cerebral hemiatrophy was seen in three patients. The signal intensity of the parenchymal germinomas was heterogeneous on T1- and T2-weighted images due to haemorrhage, cysts and solid portions. We also report the MRI findings of germinomas in an early stage in two patients. (orig.) With 5 figs., 1 tab., 17 refs.

  9. Hyper-arousal decreases human visual thresholds.

    Directory of Open Access Journals (Sweden)

    Adam J Woods

    Full Text Available 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.

  10. Hyper-arousal decreases human visual thresholds.

    Science.gov (United States)

    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.

  11. Neuroendocrine carcinomas arising in ulcerative colitis:Coincidences or possible correlations?

    Institute of Scientific and Technical Information of China (English)

    Roberto Grassia; Paolo Bodini; Paolo Dizioli; Teresa Staiano; Elena Iiritano; Guglielmo Bianchi; Federico Buffoli

    2009-01-01

    Patients with inflammatory bowel disease (IBD) are at increased risk of colorectal malignancies. Adenocarcinoma is the commonest type of colorectal neoplasm associated with ulcerative colitis (UC) and Crohn's disease,but other types of epithelial and non-epithelial tumors have also been described in inflamed bowel.With regards to non-epithelial malignancies, lymphomas and sarcomas represent the largest group oftumors reported in association with IBD, especially in immunosuppressed patients. Carcinoids and in particular neuroendocrine neoplasms other than carcinoids (NENs) are rare tumors and are infrequently described in the setting of IBD. Thus, this association requires further investigation. We report two cases of neoplasms arising in mild left-sided UC with immunohistochemical staining for neuroendocrine markers: a large cell and a small cell neuroendocrine carcinoma of the rectum. The two patients were different in age (35 years vs 77 years) and disease duration (11 years vs 27 years), and both had never received immunosuppressant drugs. Although the patients underwent regular endoscopic and histological follow-up, the two neoplasms were locally advanced at diagnosis. One of the two patients developed multiple liver metastases and died 15 mo after diagnosis. These findings confirm the aggressiveness and the poor prognosis of NENs compared to colorectal adenocarcinoma. While carcinoids seem to be coincidentally associated with IBD,NENs may also arise in this setting. In fact, long-standing inflammation could be directly responsible for the development of pancellular dysplasia involving epithelial,goblet, Paneth and neuroendocrine cells. It has yetto be established which IBD patients have a higher risk of developing NENs.

  12. Medical image of the week: lactate threshold

    Directory of Open Access Journals (Sweden)

    Dalabih MR

    2016-03-01

    Full Text Available The lactate or anaerobic threshold in exercise physiology is the point at which lactic acid starts to accumulate as the anaerobic component of metabolism increases and has been used to assess cardiopulmonary fitness. The V-slope method is a non-invasive way of estimating the lactate or anaerobic threshold (1. As lactate accumulates the H+ is mainly buffered by HCO3- and produces CO2. A point can be seen in Figure 1 where CO2 production (VCO2 abruptly increases relative to O2 consumption (VO2 . This represents the point at which anaerobic threshold occurs.

  13. Voting on Thresholds for Public Goods

    DEFF Research Database (Denmark)

    Rauchdobler, Julian; Sausgruber, Rupert; Tyran, Jean-Robert

    Introducing a threshold in the sense of a minimal project size transforms a public goods game with an inefficient equilibrium into a coordination game with a set of Pareto-superior equilibria. Thresholds may therefore improve efficiency in the voluntary provision of public goods. In our one-shot ...... in a referendum, because voting may facilitate coordination due to signaling and commitment effects. We find that voting does have signaling and commitment effects but they are not strong enough to significantly improve the efficiency of thresholds....

  14. Voting on Thresholds for Public Goods

    DEFF Research Database (Denmark)

    Rauchdobler, Julian; Sausgruber, Rupert; Tyran, Jean-Robert

    2010-01-01

    Introducing a threshold in the sense of a minimal project size transforms a public-good game with an inefficient equilibrium into a coordination game with a set of Pareto-superior equilibria. Thresholds may therefore improve efficiency in the voluntary provision of public goods. In our one-shot e...... is approved in a referendum, because voting may facilitate coordination due to signaling and commitment effects. We find that voting does have signaling and commitment effects, but they are not strong enough to significantly improve the efficiency of thresholds....

  15. Experimental realization of chaos control by thresholding.

    Science.gov (United States)

    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.

  16. Intensify Denoisy Image Using Adaptive Multiscale Product Thresholding

    Directory of Open Access Journals (Sweden)

    Mr. Anup T. Gadre,

    2015-06-01

    Full Text Available This Paper presents a wavelet-based multiscale products thresholding scheme for noise suppression of magnetic resonance images. This paper proposed a method based on image de-noising and edge enhancement of noisy multidimensional imaging data sets. Medical images are generally suffered from signal dependent noises i.e. speckle noise and broken edges. Most of the noises signals appear from machine and environment generally not contribute to the tissue differentiation. But, the noise generated due to above mentioned reason causes a grainy appearance on the image, hence image enhancement is required. For the intent of image denoising, Adaptive Multiscale Product Thresholding based on 2-D wavelet transform is used. In this method, contiguous wavelet sub bands are multiplied to improve edge structure while reducing noise. In multiscale products, boundaries can be successfully distinguished from noise. Adaptive threshold is designed and forced on multiscale products as an alternative of wavelet coefficients or recognize important features. For the edge enhancement. Canny Edge Detection Algorithm is used with scale multiplication technique. Simulation results shows that the planned technique better suppress the Poisson noise among several noises i.e. salt & pepper, speckle noise and random noise. The Performance of Image Intesification can be estimate by means of PSNR, MSE.

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

    Science.gov (United States)

    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.

  18. Nonlinear theory of kinetic instabilities near threshold

    Energy Technology Data Exchange (ETDEWEB)

    Berk, H.L.; Pekker, M.S. [Univ. of Texas, Austin, TX (United States). Inst. for Fusion Studies; Breizman, B.N. [Texas Univ., Austin, TX (United States). Inst. for Fusion Studies]|[Budker Inst. of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-05-01

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

  19. 40 CFR 98.411 - Reporting threshold.

    Science.gov (United States)

    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 GHG emissions....

  20. 40 CFR 98.181 - Reporting threshold.

    Science.gov (United States)

    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...

  1. 40 CFR 98.341 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

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

  2. 40 CFR 98.191 - Reporting threshold.

    Science.gov (United States)

    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...

  3. 40 CFR 98.391 - Reporting threshold.

    Science.gov (United States)

    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....

  4. 40 CFR 98.71 - Reporting threshold.

    Science.gov (United States)

    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...

  5. 40 CFR 98.271 - Reporting threshold.

    Science.gov (United States)

    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...

  6. 40 CFR 98.381 - Reporting threshold.

    Science.gov (United States)

    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....

  7. 40 CFR 98.291 - Reporting threshold.

    Science.gov (United States)

    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...

  8. 40 CFR 98.161 - Reporting threshold.

    Science.gov (United States)

    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...

  9. 40 CFR 98.31 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING General Stationary Fuel Combustion Sources § 98.31 Reporting threshold. You must report GHG emissions under this subpart if your facility contains one or more stationary...

  10. 40 CFR 98.111 - Reporting threshold.

    Science.gov (United States)

    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...

  11. 40 CFR 98.41 - Reporting threshold.

    Science.gov (United States)

    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...

  12. 40 CFR 98.151 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING HCFC-22 Production and HFC-23 Destruction § 98.151 Reporting threshold. You must report GHG emissions under this subpart if your facility contains an HCFC-22 production...

  13. 40 CFR 98.81 - Reporting threshold.

    Science.gov (United States)

    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...

  14. 40 CFR 98.251 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Petroleum Refineries § 98.251 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a petroleum refineries process and the facility...

  15. 40 CFR 98.281 - Reporting threshold.

    Science.gov (United States)

    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...

  16. 40 CFR 98.211 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Miscellaneous Uses of Carbonate § 98.211 Reporting threshold. You must report GHG emissions from miscellaneous uses of carbonate if your facility uses carbonates as defined...

  17. 40 CFR 98.51 - Reporting threshold.

    Science.gov (United States)

    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...

  18. 40 CFR 98.311 - Reporting threshold.

    Science.gov (United States)

    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...

  19. 40 CFR 98.221 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

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

  20. 40 CFR 98.261 - Reporting threshold.

    Science.gov (United States)

    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...

  1. 40 CFR 98.171 - Reporting threshold.

    Science.gov (United States)

    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...

  2. 40 CFR 98.331 - Reporting threshold.

    Science.gov (United States)

    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...

  3. 40 CFR 98.141 - Reporting threshold.

    Science.gov (United States)

    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...

  4. 40 CFR 98.241 - Reporting threshold.

    Science.gov (United States)

    2010-07-01

    ...) MANDATORY GREENHOUSE GAS REPORTING Petrochemical Production § 98.241 Reporting threshold. You must report GHG emissions under this subpart if your facility contains a petrochemical process as specified...

  5. 40 CFR 98.61 - Reporting threshold.

    Science.gov (United States)

    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...

  6. Secure information management using linguistic threshold approach

    CERN Document Server

    Ogiela, Marek R

    2013-01-01

    This book details linguistic threshold schemes for information sharing. It examines the opportunities of using these techniques to create new models of managing strategic information shared within a commercial organisation or a state institution.

  7. Effective theories and thresholds in particle physics

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Directory of Open Access Journals (Sweden)

    Tom Burr

    2013-01-01

    Full Text Available 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. 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.

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

    Science.gov (United States)

    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. Optimizing Retransmission Threshold in Wireless Sensor Networks.

    Science.gov (United States)

    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.

  11. Dynamic Threshold Public-Key Encryption

    OpenAIRE

    Delerablée, Cécile; Pointcheval, David

    2008-01-01

    The original publication is available at www.springerlink.com; International audience; This paper deals with threshold public-key encryption which allows a pool of players to decrypt a ciphertext if a given threshold of authorized players cooperate. We generalize this primitive to the dynamic setting, where any user can dynamically join the system, as a possible recipient; the sender can dynamically choose the authorized set of recipients, for each ciphertext; and the sender can dynamically s...

  12. A RARE CASE REPORT OF SQUAMOUS CELL CARCINOMA OF URETHRA ARISING FROM SUBSTITUTED PENILE SKIN FLAP WITH BALANITIS XEROTICA OBLITERANS

    Directory of Open Access Journals (Sweden)

    Rana Pratap

    2016-06-01

    Full Text Available A 44-year-old male presented with ulcerative growth over dorsal penile shaft along with multiple urethrocutaneous fistula. A total penectomy, scrotal excision and perineal urethrostomy were done. Past history of treatment for penile urethral stricture due to Balanitis Xerotica Obliterans (BXO by substitution urethroplasty using pedicled preputial penile skin flap five years back. On gross as well as histopathological examination, the tumour was found to be arising from the skin flap used for substitution. This case highlights the malignant potential of skin affected by BXO and is probably the only case report where a skin flap has turned malignant.

  13. Potential mechanisms for fine-scale variation in desertification thresholds

    Science.gov (United States)

    Duniway, M. C.; Peters, D. P.; Herrick, J. E.

    2007-12-01

    The process of desertification includes many interactions and feedbacks occurring at multiple spatial scales, often resulting in nonlinear dynamics and threshold behavior. These interactions and feedbacks have been observed in the broad-scale transition of former black grama grasslands to mesquite dominated shrublands (desertification) in the Chihuahuan Desert of southern New Mexico, USA. Heterogeneity in soil properties at the landscape scale can increase resistance to change, thereby reducing the probability of crossing a threshold at some sites due to small scale, within patch processes. Observational studies indicate that grass communities occurring in sandy soils shallow to well-developed petrocalcic horizons are more resistant to drought than those growing on similar soils without a this horizon. To assess the mechanism for this observed resistance, water availability dynamics were monitored in a multiyear, landscape scale study across soils with differing degrees of petrocalcic development. Results show that petrocalcic horizons absorbed and retained much greater amounts of available soil water for several months following an extremely wet winter and summer than similar depths in a deep sandy soil. Wetting and drying dynamics indicate the mechanism for the observed resistance of grasses to drought on these soils is the slow release of petrocalcic water into the grass rooting zone. The petrocalcic soil- water dynamics observed during these extreme events indicate that the high water holding capacity of these soils can potentially buffer effects of increased variability in precipitation expected to occur as a result of climate change. In water limited systems, water holding capacity of the entire profile, including rock-like material such as calcium carbonate, should be considered when evaluating the potential resistance of sites to crossing a threshold, particularly in a changing climate. Areas that are inherently more resistant to patch-scale shrub invasion

  14. The Low-Threshold Calcium Channel Cav3.2 Determines Low-Threshold Mechanoreceptor Function

    Directory of Open Access Journals (Sweden)

    Amaury François

    2015-01-01

    Full Text Available The T-type calcium channel Cav3.2 emerges as a key regulator of sensory functions, but its expression pattern within primary afferent neurons and its contribution to modality-specific signaling remain obscure. Here, we elucidate this issue using a unique knockin/flox mouse strain wherein Cav3.2 is replaced by a functional Cav3.2-surface-ecliptic GFP fusion. We demonstrate that Cav3.2 is a selective marker of two major low-threshold mechanoreceptors (LTMRs, Aδ- and C-LTMRs, innervating the most abundant skin hair follicles. The presence of Cav3.2 along LTMR-fiber trajectories is consistent with critical roles at multiple sites, setting their strong excitability. Strikingly, the C-LTMR-specific knockout uncovers that Cav3.2 regulates light-touch perception and noxious mechanical cold and chemical sensations and is essential to build up that debilitates allodynic symptoms of neuropathic pain, a mechanism thought to be entirely A-LTMR specific. Collectively, our findings support a fundamental role for Cav3.2 in touch/pain pathophysiology, validating their critic pharmacological relevance to relieve mechanical and cold allodynia.

  15. Threshold Based Opportunistic Scheduling of Secondary Users in Underlay Cognitive Radio Networks

    KAUST Repository

    Song, Yao

    2011-12-01

    In underlay cognitive radio networks, secondary users can share the spectrum with primary users as long as the interference caused by the secondary users to primary users is below a certain predetermined threshold. It is reasonable to assume that there is always a large pool of secondary users trying to access the channel, which can be occupied by only one secondary user at a given time. As a result, a multi-user scheduling problem arises among the secondary users. In this thesis, by manipulating basic schemes based on selective multi-user diversity, normalized thresholding, transmission power control, and opportunistic round robin, we propose and analyze eight scheduling schemes of secondary users in an underlay cognitive radio set-up. The system performance of these schemes is quantified by using various performance metrics such as the average system capacity, normalized average feedback load, scheduling outage probability, and system fairness of access. In our proposed schemes, the best user out of all the secondary users in the system is picked to transmit at each given time slot in order to maximize the average system capacity. Two thresholds are used in the two rounds of the selection process to determine the best user. The first threshold is raised by the power constraint from the primary user. The second threshold, which can be adjusted by us, is introduced to reduce the feedback load. The overall system performance is therefore dependent on the choice of these two thresholds and the number of users in the system given the channel conditions for all the users. In this thesis, by deriving analytical formulas and presenting numerical examples, we try to provide insights of the relationship between the performance metrics and the involved parameters including two selection thresholds and the number of active users in the system, in an effort to maximize the average system capacity as well as satisfy the requirements of scheduling outage probability and

  16. Angiosarcoma arising in schwannoma of cerebellopontine angle and later associating with meningioma in a patient with neurofibromatosis type 2.

    Science.gov (United States)

    Sakai, Yasuhiro; Hirose, Takanori; Tomono, Ayako; Kawakami, Fumi; Nakai, Tokiko; Ohbayashi, Chiho; Mizowaki, Takashi; Tanaka, Kazuhiro; Kohmura, Eiji; Itoh, Tomoo

    2014-10-01

    Here, we describe an extremely rare case of angiosarcoma arising in schwannoma of the cerebellopontine angle and later associating with meningioma in a patient with neurofibromatosis type 2. A 33-year-old disabled Japanese man with right drop foot after surgery for an unspecified tumor demonstrated multiple tumors, suspected to be schwannoma, in the bilateral cerebellopontine angles, the cervical and lumbar spinal cord, and on the right nuchal skin. Also present were several tumors in the medulla and thoracic spinal cord suspected to be ependymoma or astrocytoma. The patient was diagnosed with neurofibromatosis type 2 according to the diagnostic criteria by the U.S. National Institutes of Health. The bilateral tumors in the cerebellopontine angle were resected to reduce symptoms and brain stem compression. Histopathological analysis revealed angiosarcoma arising in schwannoma of the bilateral tumors, and angiosarcoma was proportionally larger in the right tumor than in the left. At age 36, the patient underwent a second resection of the regrown tumor in the left cerebellopontine angle, and histopathology demonstrated mixed angiosarcoma and meningioma. That angiosarcoma arises in schwannoma is a pathogenesis within the realm of conjecture, especially that the phenomenon of mixed meningioma and angiosarcoma has not been reported to date.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    2015-08-01

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

  19. The Value of Risk Pooling for Mitigating Water Utility Financial Risks Arising From Water Scarcity

    Science.gov (United States)

    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.

  20. Low-grade myofibroblastic sarcoma arising in fibroadenoma of the breast-A case report.

    Science.gov (United States)

    Myong, Na-Hye; Min, Jun-Won

    2016-03-25

    Myofibroblastic sarcoma or myofibrosarcoma is a malignant tumor of myofibroblasts and known to develop rarely in the breast, but its underlying lesion and tumor cell origin have never been reported yet. A 61-year-old female presented with a gradually growing breast mass with well-demarcated ovoid nodular shape. The tumor was histologically characterized by fascicular-growing spindle cell proliferation with large areas of hyalinized fibrosis and focally ductal epithelial remnants embedded in myxoid stroma, mimicking a fibroadenomatous lesion. It had frequent mitoses of 5-16/10 high-power fields, hemorrhagic necrosis, and focally pericapsular invasion. The spindle cells were diffusely immunoreactive for fibronectin, smooth muscle actin, and calponin, which suggest a myofibroblastic origin. Multiple irregularly thickened vessels with medial or pericytic cell proliferation were found to be merged with the intrinsic tumor cells. The tumor could be diagnosed low-grade myofibroblastic sarcoma arising in an old fibroadenoma. We report a case of a low-grade mammary myofibrosarcoma that showed a background lesion of fibroadenoma first in the worldwide literature and suggest the pericytes or medial muscle cells of the intratumoral vessels as the cell origin of the myofibroblastic sarcoma.

  1. Existence of solutions to boundary value problems arising from the fractional advection dispersion equation

    Directory of Open Access Journals (Sweden)

    Lingju Kong

    2013-04-01

    Full Text Available We study the existence of multiple solutions to the boundary value problem $$displaylines{ frac{d}{dt}Big(frac12{}_0D_t^{-eta}(u'(t+frac12{}_tD_T^{-eta}(u'(t Big+lambda abla F(t,u(t=0,quad tin [0,T],cr u(0=u(T=0, }$$ where $T>0$, $lambda>0$ is a parameter, $0leqeta<1$, ${}_0D_t^{-eta}$ and ${}_tD_T^{-eta}$ are, respectively, the left and right Riemann-Liouville fractional integrals of order $eta$, $F: [0,T]imesmathbb{R}^Nomathbb{R}$ is a given function. Our interest in the above system arises from studying the steady fractional advection dispersion equation. By applying variational methods, we obtain sufficient conditions under which the above equation has at least three solutions. Our results are new even for the special case when $eta=0$. Examples are provided to illustrate the applicability of our results.

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

    Directory of Open Access Journals (Sweden)

    J. D. Phillips

    2006-04-01

    Full Text Available 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

  3. Identifying Threshold Concepts for Information Literacy: A Delphi Study

    Directory of Open Access Journals (Sweden)

    Lori Townsend

    2016-06-01

    Full Text Available This study used the Delphi method to engage expert practitioners on the topic of threshold concepts for information literacy. A panel of experts considered two questions. First, is the threshold concept approach useful for information literacy instruction? The panel unanimously agreed that the threshold concept approach holds potential for information literacy instruction. Second, what are the threshold concepts for information literacy instruction? The panel proposed and discussed over fifty potential threshold concepts, finally settling on six information literacy threshold concepts.

  4. Renormalizability of reggeon field theory accounting for thresholds and ''mass'' terms at D=2

    Energy Technology Data Exchange (ETDEWEB)

    Eremyan, Sh.S.; Nazaryan, A.Eh. (Erevanskij Fizicheskij Inst. (USSR))

    1982-12-01

    It is shown that accounting for thresholds of the reggeon production, xi/sub 0/=ln(M/sup 2//s/sub 0/) approximately 2, in the reggeon field theory results in the fact that the epsilon expansion becomes analytical at epsilon=2, so a possibility arises of a simultaneous limit epsilon ..-->.. 2 and E ..-->.. 0, which corresponds to the physical dimensionality in the energy asymptotics. Introducton of the thresholds simplifies the perturbational calculations at D=2 dimension, eliminating ultraviolet divergences from the theory, and it was found also useful for a smooth joining of the perturbational solution with the asymptotics.

  5. Asymmetries arising from the space-filling nature of vascular networks

    Science.gov (United States)

    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.

  6. Color assimilation and contrast near absolute threshold

    Science.gov (United States)

    McCann, John

    2012-01-01

    Simultaneous Contrast and Assimilation test targets are almost always viewed at high light levels. We measured the appearances of Simultaneous Contrast, Assimilation and other spatial surrounds near absolute rod threshold. Given the very different spatial organizations of receptive fields in rod and cone vision at detection threshold, it is not obvious that these familiar cone-vision spatial effects would be observed at rod light levels. Nevertheless, the spatial experiments showed that these targets have the same changes in appearance as those observed in bright light. Our experiments used very dim candle light that was above threshold for rods and L cones, and below threshold for M and S cones. Although detection threshold experiments show very different spatial organizations for rod and cone vision, we found that spatial contrast experiments gave the same changes of appearance. Neural contrast mechanisms at the lowest end of our visual HDR range are very similar to those at the top of the range in sunlight. This is true for both chromatic and achromatic targets.

  7. At-Risk-of-Poverty Threshold

    Directory of Open Access Journals (Sweden)

    Táňa Dvornáková

    2012-06-01

    Full Text Available European Statistics on Income and Living Conditions (EU-SILC is a survey on households’ living conditions. The main aim of the survey is to get long-term comparable data on social and economic situation of households. Data collected in the survey are used mainly in connection with the evaluation of income poverty and determinationof at-risk-of-poverty rate. This article deals with the calculation of the at risk-of-poverty threshold based on data from EU-SILC 2009. The main task is to compare two approaches to the computation of at riskof-poverty threshold. The first approach is based on the calculation of the threshold for each country separately,while the second one is based on the calculation of the threshold for all states together. The introduction summarizes common attributes in the calculation of the at-risk-of-poverty threshold, such as disposable household income, equivalised household income. Further, different approaches to both calculations are introduced andadvantages and disadvantages of these approaches are stated. Finally, the at-risk-of-poverty rate calculation is described and comparison of the at-risk-of-poverty rates based on these two different approaches is made.

  8. IMAGE WAVELET DENOISING USING THE ROBUST LOCAL THRESHOLD

    Institute of Scientific and Technical Information of China (English)

    LinKezheng; ZhouHongyu; 等

    2002-01-01

    This paper suggests a scheme of image denoising based on two-dimensional discrete wavelet transform.The denoising algorithm is described with some operatiors.By thresholding the wavelet transform coefficients of noisy images, the original image can be reconstructed cor-rectly.Different threshold selections and thresholding methods are discussed.A new robust local threshold scheme is proposed.Quantifying the performance of image denoising schemes by using the mean square error, the performance of the robust local threshold scheme is demonstrated and is compared with the universal threshold scheme.The experiment shows that image denoising using the robust local threshold performs better than that using the universal threshold.

  9. IMAGE WAVELET DENOISING USING THE ROBUST LOCAL THRESHOLD

    Institute of Scientific and Technical Information of China (English)

    Lin Kezheng; Zhou Hongyu; Li Dianpu

    2002-01-01

    This paper suggests a scheme of image denoising based on two-dimensional discrete wavelet transform. The denoising algorithm is described with some operators. By thresholding the wavelet transform coefficients of noisy images, the original image can be reconstructed correctly. Different threshold selections and thresholding methods are discussed. A new robust local threshold scheme is proposed. Quantifying the performance of image denoising schemes by using the mean square error, the performance of the robust local threshold scheme is demonstrated and is compared with the universal threshold scheme. The experiment shows that image denoising using the robust local threshold performs better than that using the universal threshold.

  10. The evolution of altruism in spatial threshold public goods games via an insurance mechanism

    NARCIS (Netherlands)

    Zhang, Jianlei; Zhang, Chunyan

    2015-01-01

    The persistence of cooperation in public goods situations has become an important puzzle for researchers. This paper considers the threshold public goods games where the option of insurance is provided for players from the standpoint of diversification of risk, envisaging the possibility of multiple

  11. Electron-Nuclear Energy Sharing in Above-Threshold Multiphoton Dissociative Ionization of H2

    DEFF Research Database (Denmark)

    Wu, J.; Kunitski, M.; Pitzer, M.

    2013-01-01

    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....

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

    Science.gov (United States)

    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.

  13. Threshold learning dynamics in social networks

    CERN Document Server

    González-Avella, J C; Marsili, M; Vega-Redondo, F; Miguel, M San

    2010-01-01

    Social learning is defined as the ability of a population to aggregate information, a process which must crucially depend on the mechanisms of social interaction. Consumers choosing which product to buy, or voters deciding which option to take respect to an important issues, typically confront external signals to the information gathered from their contacts. Received economic models typically predict that correct social learning occurs in large populations unless some individuals display unbounded influence. We challenge this conclusion by showing that an intuitive threshold process of individual adjustment does not always lead to such social learning. We find, specifically, that three generic regimes exist. And only in one of them, where the threshold is within a suitable intermediate range, the population learns the correct information. In the other two, where the threshold is either too high or too low, the system either freezes or enters into persistent flux, respectively. These regimes are generally obse...

  14. L-H Threshold Studies in NSTX

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Predictability of threshold exceedances in dynamical systems

    Science.gov (United States)

    Bódai, Tamás

    2015-12-01

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

  16. Biased parameter estimates and inflated Type I error rates in analysis of covariance (and analysis of partial variance) arising from unreliability: alternatives and remedial strategies.

    Science.gov (United States)

    Zinbarg, Richard E; Suzuki, Satoru; Uliaszek, Amanda A; Lewis, Alison R

    2010-05-01

    Miller and Chapman (2001) argued that 1 major class of misuse of analysis of covariance (ANCOVA) or its multiple regression counterpart, analysis of partial variance (APV), arises from attempts to use an ANCOVA/APV to answer a research question that is not meaningful in the 1st place. Unfortunately, there is another misuse of ANCOVAs/APVs that arises frequently in psychopathology studies even when addressing consensually meaningful research questions. This misuse arises from inflated Type I error rates in ANCOVA/APV inferential tests of the unique association of the independent variable with the dependent variable when the covariate and independent variables are correlated and measured with error. Alternatives to conventional ANCOVAs/APVs are discussed, as are steps that can be taken to minimize the impact of this bias on drawing valid inferences when conventional ANCOVAs/APVs are used.

  17. Thresholded Range Aggregation in Sensor Networks

    DEFF Research Database (Denmark)

    Yiu, Man Lung; Lin, Zhifeng; Mamoulis, Nikos

    2010-01-01

    called thresholded range aggregate query (TRA), which retrieves the IDs of the sensors for which the average measurement in their neighborhood exceeds a user-given threshold. This query provides results that they are robust against individual sensor abnormality, and yet precisely summarize the sensors......' status in each local region. In order to process the (snapshot) TRA query, we develop energy-efficient protocols based on appropriate operators and filters in sensor nodes. The design of these operators and filters is non-trivial, due to the fact that each sensor measurement influences the actual results...

  18. Mass threshold for ’harmless’ drones

    DEFF Research Database (Denmark)

    la Cour-Harbo, Anders

    2017-01-01

    a category labeled ’Harmless’, which should be based on a mass threshold. To aid such a classification this work proposes a mass threshold of 250 grams, below which, we argue, it is reasonable to classify drones as ’harmless’ in the sense that the expected fatality rate is equivalent to that of manned...... approach in this work is based a numerous assumptions, such as the reliability of drones, the average mass to speed ratio, and the severity of drone inflicted injuries....

  19. Determining lower threshold concentrations for synergistic effects

    DEFF Research Database (Denmark)

    Bjergager, Maj-Britt Andersen; Dalhoff, Kristoffer; Kretschmann, Andreas;

    2017-01-01

    on synergistic interactions between the pyrethroid insecticide, alpha-cypermethrin, and one of the three azole fungicides prochloraz, propiconazole or epoxiconazole measured on Daphnia magna immobilization. Three different experimental setups were applied: A standard 48h acute toxicity test, an adapted 48h test.......7 fold higher than the horizontal assessments. Using passive dosing rather than dilution series or spiking did not lower the threshold significantly. Below the threshold for synergy, slight antagony could often be observed. This is most likely due to induction of enzymes active in metabolization of alpha...

  20. Near-threshold correlations of neutrons

    CERN Document Server

    Okołowicz, J; Nazarewicz, W

    2013-01-01

    The appearance of charged-particle clustering in near-threshold configuration is a phenomenon that can be explained in the Open Quantum System description of the atomic nucleus. In this work we apply the realistic Shell Model Embedded in the Continuum to elucidate the emergence of neutron correlations in near-threshold many-body states coupled to l=1,2 neutron decay channels. Spectral consequences of such continuum coupling are briefly discussed together with the emergence of complex multi-neutron correlations.

  1. Interregional migration and thresholds: evidence in Spain

    OpenAIRE

    Clemente, Jesús; Larramona, Gemma; Olmos, Lorena

    2013-01-01

    The aim of this paper is to analyze the effects of labor market conditions in the origin and the destination on interregional migration in Spain, over the period 1988-2010. A basic theoretical framework is developed and the implications of the model suggest that the effect of labor market conditions on migration can vary, depending on a certain threshold. In a second step, the implications of the model are tested with Spanish data, using a new approach based on the presence of thresholds. We...

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

    Science.gov (United States)

    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.

  3. Multiple routes transmitted epidemics on multiplex networks

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Dawei [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Shandong Provincial Key Laboratory of Computer Network, Shandong Computer Science Center, Jinan 250014 (China); Li, Lixiang [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Peng, Haipeng, E-mail: penghaipeng@bupt.edu.cn [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Luo, Qun; Yang, Yixian [Information Security Center, State Key Laboratory of Networking and Switching Technology, Beijing University of Posts and Telecommunications, P.O. Box 145, Beijing 100876 (China); National Engineering Laboratory for Disaster Backup and Recovery, Beijing University of Posts and Telecommunications, Beijing 100876 (China)

    2014-02-01

    This letter investigates the multiple routes transmitted epidemic process on multiplex networks. We propose detailed theoretical analysis that allows us to accurately calculate the epidemic threshold and outbreak size. It is found that the epidemic can spread across the multiplex network even if all the network layers are well below their respective epidemic thresholds. Strong positive degree–degree correlation of nodes in multiplex network could lead to a much lower epidemic threshold and a relatively smaller outbreak size. However, the average similarity of neighbors from different layers of nodes has no obvious effect on the epidemic threshold and outbreak size. -- Highlights: •We studies multiple routes transmitted epidemic process on multiplex networks. •SIR model and bond percolation theory are used to analyze the epidemic processes. •We derive equations to accurately calculate the epidemic threshold and outbreak size. •ASN has no effect on the epidemic threshold and outbreak size. •Strong positive DDC leads to a lower epidemic threshold and a smaller outbreak size.

  4. Multi-Species Measurements of the Firehose and Mirror Instability Thresholds in the Solar Wind

    CERN Document Server

    Chen, C H K; Schekochihin, A A; Stevens, M L; Salem, C S; Maruca, B A; Kunz, M W; Bale, S D

    2016-01-01

    The firehose and mirror instabilities are thought to arise in a variety of space and astrophysical plasmas, constraining the pressure anisotropies and drifts between particle species. The plasma stability depends on all species simultaneously, meaning that a combined analysis is required. Here, we present the first such analysis in the solar wind, using the long-wavelength stability parameters to combine the anisotropies and drifts of all major species (core and beam protons, alphas, and electrons). At the threshold, the firehose parameter was found to be dominated by protons (67%), but also to have significant contributions from electrons (18%) and alphas (15%). Drifts were also found to be important, contributing 57% in the presence of a proton beam. A similar situation was found for the mirror, with contributions of 61%, 28%, and 11% for protons, electrons, and alphas, respectively. The parallel electric field contribution, however, was found to be small at 9%. Overall, the long-wavelength thresholds const...

  5. 28 CFR 45.2 - Disqualification arising from personal or political relationship.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Disqualification arising from personal or political relationship. 45.2 Section 45.2 Judicial Administration DEPARTMENT OF JUSTICE (CONTINUED) EMPLOYEE RESPONSIBILITIES § 45.2 Disqualification arising from personal or political relationship. (a) Unless...

  6. 31 CFR 535.335 - Claim arising out of events in Iran.

    Science.gov (United States)

    2010-07-01

    ... 31 Money and Finance: Treasury 3 2010-07-01 2010-07-01 false Claim arising out of events in Iran. 535.335 Section 535.335 Money and Finance: Treasury Regulations Relating to Money and Finance... General Definitions § 535.335 Claim arising out of events in Iran. For purposes of § 535.216, a claim...

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

    Science.gov (United States)

    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.

  8. Multiple Sclerosis

    Science.gov (United States)

    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 ...

  9. Multiple Myeloma

    Science.gov (United States)

    Multiple myeloma is a cancer that begins in plasma cells, a type of white blood cell. These cells ... bones. No one knows the exact causes of multiple myeloma, but it is more common in older people ...

  10. Sigmoid colon cancer arising in a diverticulum of the colon with involvement of the urinary bladder: a case report and review of the literature

    Science.gov (United States)

    2014-01-01

    Background Colon cancer can arise from the mucosa in a colonic diverticulum. Although colon diverticulum is a common disease, few cases have been previously reported on colon cancer associated with a diverticulum. We report a rare case of sigmoid colon cancer arising in a diverticulum with involvement of the urinary bladder, which presented characteristic radiographic images. Case presentation A 73-year-old man was admitted to our hospital for macroscopic hematuria. Computed tomography and magnetic resonance imaging revealed a sigmoid colon tumor that protruded into the urinary bladder lumen. The radiographs showed a tumor with a characteristic dumbbell-shaped appearance. Colonoscopy showed a type 1 cancer and multiple diverticula in the sigmoid colon. A diagnosis of sigmoid colon cancer with involvement of the urinary bladder was made based on the pathological findings of the biopsied specimens. We performed sigmoidectomy and total resection of the urinary bladder with colostomy and urinary tract diversion. Histopathological findings showed the presence of a colovesical fistula due to extramurally growing colon cancer. Around the colon cancer, the normal colon mucosa was depressed sharply with lack of the muscular layer, suggesting that the colon cancer was arising from a colon diverticulum. Conclusion The present case is the first report of sigmoid colon cancer arising in a diverticulum with involvement of the urinary bladder. Due to an accurate preoperative radiological diagnosis, we were able to successfully perform a curative resection for sigmoid colon cancer arising in a diverticulum with involvement of the urinary bladder. PMID:24884743

  11. Determination of optimum threshold values for EMG time domain features; a multi-dataset investigation

    Science.gov (United States)

    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

  12. Design of Threshold Controller Based Chaotic Circuits

    DEFF Research Database (Denmark)

    Mohamed, I. Raja; Murali, K.; Sinha, Sudeshna

    2010-01-01

    We propose a very simple implementation of a second-order nonautonomous chaotic oscillator, using a threshold controller as the only source of nonlinearity. We demonstrate the efficacy and simplicity of our design through numerical and experimental results. Further, we show that this approach of ...

  13. The Resting Motor Threshold - Restless or Resting?

    DEFF Research Database (Denmark)

    Karabanov, Anke Ninija; Raffin, Estelle Emeline; Siebner, Hartwig Roman

    2015-01-01

    Background The resting motor threshold (RMT) is used to individually adjust the intensity of transcranial magnetic stimulation (TMS) intensity and is assumed to be stable. Here we challenge this notion by showing that RMT expresses acute context-dependent fluctuations. Method In twelve participants...

  14. Psychophysical thresholds of face visibility during infancy

    DEFF Research Database (Denmark)

    Gelskov, Sofie; Kouider, Sid

    2010-01-01

    . By contrast, 15 month-olds not only revealed adult-like thresholds, but also improved their performance through memory-based strategies. Our results imply that the development of face visibility follows a non-linear course and is determined by a radical improvement occurring between 10 and 15 months....

  15. Threshold Concepts in Finance: Conceptualizing the Curriculum

    Science.gov (United States)

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

    2015-01-01

    Graduates with well-developed capabilities in finance are invaluable to our society and in increasing demand. Universities face the challenge of designing finance programmes to develop these capabilities and the essential knowledge that underpins them. Our research responds to this challenge by identifying threshold concepts that are central to…

  16. Immune impairment thresholds in HIV infection.

    Science.gov (United States)

    Iwami, Shingo; Nakaoka, Shinji; Takeuchi, Yasuhiro; Miura, Yoshiharu; Miura, Tomoyuki

    2009-04-27

    Longitudinal studies of patients infected with HIV-1 reveal a long and variable length of asymptomatic phase between infection and development of AIDS. Some HIV infected patients are still asymptomatic after 15 or more years of infection but some patients develop AIDS within 2 years. The mechanistic basis of the disease progression has remained obscure but many researchers have been trying to explain it. For example, the possible importance of viral diversity for the disease progression and the development of AIDS has been very well worked out in the early-1990s, especially by some important works of Martin A. Nowak. These studies can give an elegant explanation for a variability of asymptomatic phase. Here, a simple mathematical model was used to propose a new explanation for a variable length of asymptomatic phase. The main idea is that the immune impairment rate increases over the HIV infection. Our model suggested the existence of so-called "Risky threshold" and "Immunodeficiency threshold" on the impairment rate. The former implies that immune system may collapse when the impairment rate of HIV exceeds the threshold value. The latter implies that immune system always collapses when the impairment rate exceeds the value. We found that the length of asymptomatic phase is determined stochastically between these threshold values depending on the virological and immunological states. Furthermore, we investigated a distribution of the length of asymptomatic phase and a survival rate of the immune responses in one HIV patient.

  17. Low-threshold conical microcavity dye lasers

    DEFF Research Database (Denmark)

    Grossmann, Tobias; Schleede, Simone; Hauser, Mario

    2010-01-01

    We report on lasing in rhodamine 6G-doped, conical polymeric microcavities with high quality factors fabricated on a silicon substrate. Threshold pump energies as low as 3 nJ are achieved by free-space excitation in the quasistationary pumping regime with lasing wavelengths around 600 nm. Finite...

  18. On non-stationary threshold autoregressive models

    CERN Document Server

    Liu, Weidong; Shao, Qi-Man; 10.3150/10-BEJ306

    2011-01-01

    In this paper we study the limiting distributions of the least-squares estimators for the non-stationary first-order threshold autoregressive (TAR(1)) model. It is proved that the limiting behaviors of the TAR(1) process are very different from those of the classical unit root model and the explosive AR(1).

  19. Threshold model of cascades in temporal networks

    CERN Document Server

    Karimi, Fariba

    2012-01-01

    Threshold models try to explain the consequences of social influence like the spread of fads and opinions. Along with models of epidemics, they constitute a major theoretical framework of social spreading processes. In threshold models on static networks, an individual changes her state if a certain fraction of her neighbors has done the same. When there are strong correlations in the temporal aspects of contact patterns, it is useful to represent the system as a temporal network. In such a system, not only contacts but also the time of the contacts are represented explicitly. There is a consensus that bursty temporal patterns slow down disease spreading. However, as we will see, this is not a universal truth for threshold models. In this work, we propose an extension of Watts' classic threshold model to temporal networks. We do this by assuming that an agent is influenced by contacts which lie a certain time into the past. I.e., the individuals are affected by contacts within a time window. In addition to th...

  20. A more efficient AES threshold implementation

    NARCIS (Netherlands)

    Bilgin, Begül; Gierlichs, Benekikt; Nikova, Svetla; Nikov, Ventzislav; Rijmen, Vincent; Pointcheval, D.; Vergnaud, D.

    2014-01-01

    Threshold Implementations provide provable security against first-order power analysis attacks for hardware and software implementations. Like masking, the approach relies on secret sharing but it differs in the implementation of logic functions. At Eurocrypt 2011 Moradi et al. published the to date

  1. Simulated Critical Differences for Speech Reception Thresholds

    Science.gov (United States)

    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…

  2. Threshold Concepts in Finance: Conceptualizing the Curriculum

    Science.gov (United States)

    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…

  3. SPICE model of memristive devices with threshold

    CERN Document Server

    Pershin, Y V

    2013-01-01

    Although memristive devices with threshold voltages are the norm rather than the exception in experimentally realizable systems, their SPICE programming has not yet been suggested. Here, we show how to implement such systems in the SPICE environment. We expect this implementation to find widespread use in circuits design and testing.

  4. 40 CFR 98.401 - Reporting threshold.

    Science.gov (United States)

    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 § 98.2(a)(4) must report GHG emissions....

  5. Threshold Theory Tested in an Organizational Setting

    DEFF Research Database (Denmark)

    Christensen, Bo T.; Hartmann, Peter V. W.; Hedegaard Rasmussen, Thomas

    2017-01-01

    A large sample of leaders (N = 4257) was used to test the link between leader innovativeness and intelligence. The threshold theory of the link between creativity and intelligence assumes that below a certain IQ level (approximately IQ 120), there is some correlation between IQ and creative...

  6. Identification of Threshold Concepts for Biochemistry

    Science.gov (United States)

    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…

  7. Multiparty Computation from Threshold Homomorphic Encryption

    DEFF Research Database (Denmark)

    Cramer, Ronald; Damgård, Ivan Bjerre; Nielsen, Jesper Buus

    2001-01-01

    We introduce a new approach to multiparty computation (MPC) basing it on homomorphic threshold crypto-systems. We show that given keys for any sufficiently efficient system of this type, general MPC protocols for n parties can be devised which are secure against an active adversary that corrupts ...

  8. Breast Cancer Detection Using Multilevel Thresholding

    CERN Document Server

    Rejani, Y Ireaneus Anna

    2009-01-01

    This paper presents an algorithm which aims to assist the radiologist in identifying breast cancer at its earlier stages. It combines several image processing techniques like image negative, thresholding and segmentation techniques for detection of tumor in mammograms. The algorithm is verified by using mammograms from Mammographic Image Analysis Society. The results obtained by applying these techniques are described.

  9. Intraoperative transfusion threshold and tissue oxygenation

    DEFF Research Database (Denmark)

    Nielsen, K; Dahl, B; Johansson, P I;

    2012-01-01

    Transfusion with allogeneic red blood cells (RBCs) may be needed to maintain oxygen delivery during major surgery, but the appropriate haemoglobin (Hb) concentration threshold has not been well established. We hypothesised that a higher level of Hb would be associated with improved subcutaneous...

  10. Perturbation of eigenvalues embedded at a threshold

    DEFF Research Database (Denmark)

    Jensen, Arne; Melgaard, Michael

    2002-01-01

    Results are obtained on perturbation of eigenvalues and half-bound states (zero-resonances) embedded at a threshold. The results are obtained in a two-channel framework for small off-diagonal perturbations. The results are based on given asymptotic expansions of the component Hamiltonians....

  11. Collaboration, Multiple Methods, Trustworthiness: Issues Arising from the 2014 International Conference on Self-Study of Teacher Education Practices

    Science.gov (United States)

    Mena, Juanjo; Russell, Tom

    2017-01-01

    This article reviews 65 studies presented at the 10th international self-study of teacher education practices conference in 2014 to determine whether emerging self-study research incorporates the five major characteristics of self-study: self-initiated inquiry that is situated and improvement-aimed; undertaken collaboratively; uses multiple…

  12. Intervention thresholds for osteoporosis in the UK.

    Science.gov (United States)

    Kanis, John A; Borgstrom, Frederik; Zethraeus, Niklas; Johnell, Olof; Oden, Anders; Jönsson, Bengt

    2005-01-01

    The aim of this study was to determine the threshold of fracture probability at which interventions became cost-effective in women based on data from the UK. We modelled the effects of an intervention costing pound 350 per year given for 5 years that decreased the risk of all osteoporotic fractures by 35% followed by a waning of effect (offset time) for a further 5 years. Sensitivity analyses included a range of treatment duration (3-10 years), intervention costs (pound 300-400/year) and offset times (0-15 years). Data on costs and risks were from the UK. Costs included direct costs, but excluded indirect costs due to morbidity. A threshold for cost-effectiveness of pound 30,000/QALY gained was used. With the base case ( pound 350 per year; 35% efficacy) treatment in women was cost-effective with a 10-year hip fracture probability that ranged from 1.1% at the age of 50 years to 9.0% at the age of 85 years. Intervention thresholds were sensitive to the assumed costs and offset time. The exclusion of osteoporotic fractures other than hip fracture significantly increased the cost-effectiveness ratio because of the substantial morbidity from such other fractures, particularly at younger ages. Cost-effective scenarios were found for women at the threshold for osteoporosis from the age of 60 years. Treatment of established osteoporosis was cost-effective irrespective of age. We conclude that the inclusion of all osteoporotic fractures has a marked effect on intervention thresholds, that these vary with age and that available treatments can be targeted cost-effectively to individuals from the UK at moderately increased fracture risk.

  13. Definition of the epileptogenic zone in a patient with non-lesional temporal lobe epilepsy arising from the dominant hemisphere.

    Science.gov (United States)

    Najm, Imad M; Naugle, Richard; Busch, Robyn M; Bingaman, William; Lüders, Hans

    2006-08-01

    Pharmacoresistant epilepsy arising from the dominant temporal region in patients with intact memory and normal anatomical imaging, presents major challenges in the preoperative definition of the epileptogenic zone, and the planning of the extent of the surgical resection. We report on the case of a 42-year-old, right-handed male who presented with recurrent daily seizures that were resistant to antiepileptic drugs. Multiple, non-invasive (scalp) video-EEG evaluations revealed focal epilepsy arising from the left fronto-temporal region. Multiple high resolution MRIs that were performed at multiple Epilepsy Centers failed to show any abnormality. Fluoro-deoxyglucose PET scan showed extensive, left antero-mesial temporal hypometabolism, and ictal SPECT showed increased perfusion in the left insula in addition to the left mesial and anterior temporal pole. Neuropsychological testing and intracarotid methohexital testing revealed excellent memory to the left, dominant side. A two-stage invasive evaluation with subdural grid electrodes followed by depth electrode recordings allowed the localization of the epileptogenic region to the temporal pole. A selective resection of the left temporal pole (that spared the hippocampal formation) resulted in a seizure-free outcome (one year follow-up) with no significant consequences on memory function. We conclude that targeted, invasive recording techniques should be used for the accurate localization and delineation of the extent of the epileptogenic zone in cases of suspected, non-lesional, dominant hemisphere, temporal lobe epilepsy with preserved memory function. The use of the staged invasive approach may increase the chances for memory (function) sparing through tailored, temporal resection.

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

    CERN Document Server

    Eisenman, I; 10.1073/pnas.0806887106

    2008-01-01

    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 while 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 ...

  15. On column density thresholds and the star formation rate

    CERN Document Server

    Clark, Paul C

    2013-01-01

    We present the results of a numerical study designed to address the question of whether there is a column density threshold for star formation within molecular clouds. We have simulated a large number of different clouds, with volume and column densities spanning a wide range of different values, using a state-of-the-art model for the coupled chemical, thermal and dynamical evolution of the gas. We show that for low-mass clouds, around 1000 solar masses and below, star formation is only possible if the mean cloud column density exceeds 10^21 cm^-2. In more massive clouds, the required mean column density is a factor of a few lower. We demonstrate that this behaviour is well-described by a simple Jeans mass argument: clouds must contain multiple Jeans masses in order to form stars, and hence star-forming clouds cannot have arbitrarily low column densities. We have also examined the question of whether there is a column density threshold for the regions within clouds where star formation occurs. We show that th...

  16. Origin of the Low Energy Structure in Above Threshold Ionization

    CERN Document Server

    Titi, Atef S

    2015-01-01

    We present an ab initio analytic theory to account for both the very low energy structure (VLES) [C. Y. Wu et al., Phys. Rev. Lett. 109, 043001 (2012); W. Quan et al., Phys. Rev. Lett. 103, 093001 (2009)], and the low energy structure (LES) [W. Quan et al. Phys. Rev. Lett. 103, 093001 (2009); C.I. Blaga et al., Nat. Phys. 5, 335 2009)] of above threshold ionization. The origin of both VLES and LES lies in a forward scattering mechanism by the Coulomb potential. We parameterize the S matrix in terms of ?, which is the displacement of the the classical motion of an electron in the laser field. When ? = 0, the S matrix is singular, which we attribute to be forward Coulomb scattering without absorption of light quanta. By devising a regularization scheme, the resulting S matrix is non-singular when ? = 0, and the origins of VLES and LES are revealed. We attribute VLES to multiple forward scattering of near-threshold electrons by the Coulomb potential, with no absorption of light quanta, signifying the role of the...

  17. High false positive rates in common sensory threshold tests.

    Science.gov (United States)

    Running, Cordelia A

    2015-02-01

    Large variability in thresholds to sensory stimuli is observed frequently even in healthy populations. Much of this variability is attributed to genetics and day-to-day fluctuation in sensitivity. However, false positives are also contributing to the variability seen in these tests. In this study, random number generation was used to simulate responses in threshold methods using different "stopping rules": ascending 2-alternative forced choice (AFC) with 5 correct responses; ascending 3-AFC with 3 or 4 correct responses; staircase 2-AFC with 1 incorrect up and 2 incorrect down, as well as 1 up 4 down and 5 or 7 reversals; staircase 3-AFC with 1 up 2 down and 5 or 7 reversals. Formulas are presented for rates of false positives in the ascending methods, and curves were generated for the staircase methods. Overall, the staircase methods generally had lower false positive rates, but these methods were influenced even more by number of presentations than ascending methods. Generally, the high rates of error in all these methods should encourage researchers to conduct multiple tests per individual and/or select a method that can correct for false positives, such as fitting a logistic curve to a range of responses.

  18. Integration of ecological-biological thresholds in conservation decision making.

    Science.gov (United States)

    Mavrommati, Georgia; Bithas, Kostas; Borsuk, Mark E; Howarth, Richard B

    2016-12-01

    In the Anthropocene, coupled human and natural systems dominate and only a few natural systems remain relatively unaffected by human influence. On the one hand, conservation criteria based on areas of minimal human impact are not relevant to much of the biosphere. On the other hand, conservation criteria based on economic factors are problematic with respect to their ability to arrive at operational indicators of well-being that can be applied in practice over multiple generations. Coupled human and natural systems are subject to economic development which, under current management structures, tends to affect natural systems and cross planetary boundaries. Hence, designing and applying conservation criteria applicable in real-world systems where human and natural systems need to interact and sustainably coexist is essential. By recognizing the criticality of satisfying basic needs as well as the great uncertainty over the needs and preferences of future generations, we sought to incorporate conservation criteria based on minimal human impact into economic evaluation. These criteria require the conservation of environmental conditions such that the opportunity for intergenerational welfare optimization is maintained. Toward this end, we propose the integration of ecological-biological thresholds into decision making and use as an example the planetary-boundaries approach. Both conservation scientists and economists must be involved in defining operational ecological-biological thresholds that can be incorporated into economic thinking and reflect the objectives of conservation, sustainability, and intergenerational welfare optimization. © 2016 Society for Conservation Biology.

  19. Altruism in multiplayer snowdrift games with threshold and punishment

    Science.gov (United States)

    Zhang, Chunyan; Liu, Zhongxin; Sun, Qinglin; Chen, Zengqiang

    2015-09-01

    The puzzle of cooperation attracts broader concerns of the scientific community nowadays. Here we adopt an extra mechanism of punishment in the framework of a threshold multiple-player snowdrift game employed as the scenario for the cooperation problem. Two scenarios are considered: defectors will suffer punishment regardless of the game results, and defectors will incur punishment only when the game fails. We show by analysis that given this assumption, punishing free riders can significantly influence the evolution outcomes, and the results are driven by the specific components of the punishing rule. Particularly, punishing defectors always, not only when the game fails, can be more effective for maintaining public cooperation in multi-player systems. Intriguingly larger thresholds of the game provide a more favorable scenario for the coexistence of the cooperators and defectors under a broad value range of parameters. Further, cooperators are best supported by the large punishment on defectors, and then dominate and stabilize in the population, under the premise that defectors always incur punishment regardless of whether the game ends successfully or not.

  20. Multiplicity Counting

    Energy Technology Data Exchange (ETDEWEB)

    Geist, William H. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    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.

  1. Efficient Processing of Multiple DTW Queries in Time Series Databases

    DEFF Research Database (Denmark)

    Kremer, Hardy; Günnemann, Stephan; Ivanescu, Anca-Maria

    2011-01-01

    . In many of today’s applications, however, large numbers of queries arise at any given time. Existing DTW techniques do not process multiple DTW queries simultaneously, a serious limitation which slows down overall processing. In this paper, we propose an efficient processing approach for multiple DTW...... for multiple DTW queries....

  2. Pre-impact fall detection system using dynamic threshold and 3D bounding box

    Science.gov (United States)

    Otanasap, Nuth; Boonbrahm, Poonpong

    2017-02-01

    Fall prevention and detection system have to subjugate many challenges in order to develop an efficient those system. Some of the difficult problems are obtrusion, occlusion and overlay in vision based system. Other associated issues are privacy, cost, noise, computation complexity and definition of threshold values. Estimating human motion using vision based usually involves with partial overlay, caused either by direction of view point between objects or body parts and camera, and these issues have to be taken into consideration. This paper proposes the use of dynamic threshold based and bounding box posture analysis method with multiple Kinect cameras setting for human posture analysis and fall detection. The proposed work only uses two Kinect cameras for acquiring distributed values and differentiating activities between normal and falls. If the peak value of head velocity is greater than the dynamic threshold value, bounding box posture analysis will be used to confirm fall occurrence. Furthermore, information captured by multiple Kinect placed in right angle will address the skeleton overlay problem due to single Kinect. This work contributes on the fusion of multiple Kinect based skeletons, based on dynamic threshold and bounding box posture analysis which is the only research work reported so far.

  3. Reduced threshold all-optical bistability in etched quantum well microresonators

    Science.gov (United States)

    Rivera, T.; Ladan, F. R.; Izrael, A.; Azoulay, R.; Kuszelewicz, R.; Oudar, J. L.

    1994-02-01

    Etched vertical microresonators made of GaAs/AlGaAs multiple quantum wells produced by reactive ion etching was investigated to study the optical bistability phenomena. Reactive ion etching was preferred because of smooth vertical and minimization of density of surface recombination centers. A high cavity finesse was observed in the microresonators producing an optical bistability with wide hysteresis loops. A low threshold power of 70 microwatts was measured due to carrier confinement and vertical walls. The low bistability threshold power was attributed to self passivation happening during etching process, which produced a small surface recombination rate.

  4. Observation of LPI Thresholds for the Nike Laser

    Science.gov (United States)

    Weaver, J. L.; Oh, J.; Afeyan, B.; Charbonneau-Lefort, M.; Phillips, L.; Seely, J.; Kehne, D.; Brown, C.; Obenschain, S.; Schmitt, A. J.; Feldman, U.; Holland, G.; Lehmberg, R. H.; McLean, E.; Manka, C.

    2008-11-01

    The Nike laser is being used to study thresholds for laser plasma instabilities (LPI) at intensities (10^15-10^16 W/cm^2) relevant to advanced implosion designs for direct drive inertial confinement fusion. The combination of short wavelength (248 nm), large bandwidth (1-2 THz), and beam smoothing by induced spatial incoherence available with this krypton-fluoride laser make these experiments unique among current facilities. This talk will present an overview of results with an emphasis on the two-plasmon decay instability (2φp). Measurements of x-rays and emission near ^1/2φo and ^3/2 φo harmonics of the laser wavelength have been collected over a wide range of intensities for both solid and foam targets. Data indicate collective multiple-angle driven excitation compatible with previous observations using solid planar targets.

  5. Ecological thresholds at the savanna-forest boundary: how plant traits, resources and fire govern the distribution of tropical biomes.

    Science.gov (United States)

    Hoffmann, William A; Geiger, Erika L; Gotsch, Sybil G; Rossatto, Davi R; Silva, Lucas C R; Lau, On Lee; Haridasan, M; Franco, Augusto C

    2012-07-01

    Fire shapes the distribution of savanna and forest through complex interactions involving climate, resources and species traits. Based on data from central Brazil, we propose that these interactions are governed by two critical thresholds. The fire-resistance threshold is reached when individual trees have accumulated sufficient bark to avoid stem death, whereas the fire-suppression threshold is reached when an ecosystem has sufficient canopy cover to suppress fire by excluding grasses. Surpassing either threshold is dependent upon long fire-free intervals, which are rare in mesic savanna. On high-resource sites, the thresholds are reached quickly, increasing the probability that savanna switches to forest, whereas low-resource sites are likely to remain as savanna even if fire is infrequent. Species traits influence both thresholds; saplings of savanna trees accumulate bark thickness more quickly than forest trees, and are more likely to become fire resistant during fire-free intervals. Forest trees accumulate leaf area more rapidly than savanna trees, thereby accelerating the transition to forest. Thus, multiple factors interact with fire to determine the distribution of savanna and forest by influencing the time needed to reach these thresholds. Future work should decipher multiple environmental controls over the rates of tree growth and canopy closure in savanna. © 2012 Blackwell Publishing Ltd/CNRS.

  6. Threshold pion electroproduction at large momentum transfers; Threshold Pion-Elektroproduktion bei grossen Energieuebertraegen

    Energy Technology Data Exchange (ETDEWEB)

    Peters, Andreas

    2008-02-15

    We consider pion electroproduction close to threshold for Q{sup 2} in the region 1-10 GeV{sup 2} on a nucleon target. The momentum transfer dependence of the S-wave multipoles at threshold, E{sub 0+} and L{sub 0+}, is calculated in the chiral limit using light-cone sum rules. Predictions for the cross sections in the threshold region are given taking into account P-wave contributions that, as we argue, are model independent to a large extent. The results are compared with the SLAC E136 data on the structure function F{sub 2}(W,Q{sup 2}) in the threshold region. (orig.)

  7. Endometrial Stromal Sarcoma Arising in Colorectal Endometriosis: A Case Report and Review of the Literature

    Directory of Open Access Journals (Sweden)

    Qiao Wang

    2015-01-01

    Full Text Available Extrauterine endometrial stromal sarcoma (ESS arising in endometriosis is extremely rare, particularly in the colorectum. It should always be included in the differential diagnosis of primary tumors originating from gastrointestinal tract in females, given that preoperative endoscopical biopsy may reveal no specific changes. We reported a case of ESS arising in colorectal endometriosis and reviewed the previous 7 cases reported in the English literature. Our patient, who was unavailable for tumor resection and refused further adjuvant therapy, played a role in representing the natural history of low-grade extragenital ESS. This case was the only death from ESS arising in colorectal endometriosis.

  8. Squamous cell carcinoma arising from an epidermal cyst in the thumb

    Science.gov (United States)

    Sakamoto, Akio; Shiba, Eisuke; Hisaoka, Masanori

    2015-01-01

    Introduction Squamous cell carcinoma arising from an epidermal cyst is rare, and the most frequently affected region is the head and neck. Presentation of case A 41-year-old man noticed swelling and a small ulceration in the thumb pulp. A lesion with a 2-cm diameter was simply resected based on a diagnosis of infected epidermal cyst. Pathological diagnosis of the resected material was squamous cell carcinoma arising from an epidermal cyst. Consequent amputation was performed. Discussion and conclusion The clinical symptoms of squamous cell carcinoma arising from an epidermal cyst can mimic those of an infected epidermal cyst. The current report facilitates awareness of such disease. PMID:25912006

  9. Computational Transition at the Uniqueness Threshold

    CERN Document Server

    Sly, Allan

    2010-01-01

    The hardcore model is a model of lattice gas systems which has received much attention in statistical physics, probability theory and theoretical computer science. It is the probability distribution over independent sets $I$ of a graph weighted proportionally to $\\lambda^{|I|}$ with fugacity parameter $\\lambda$. We prove that at the uniqueness threshold of the hardcore model on the $d$-regular tree, approximating the partition function becomes computationally hard on graphs of maximum degree $d$. Specifically, we show that unless NP$=$RP there is no polynomial time approximation scheme for the partition function (the sum of such weighted independent sets) on graphs of maximum degree $d$ for fugacity $\\lambda_c(d) 0$. Weitz produced an FPTAS for approximating the partition function when $0<\\lambda < \\lambda_c(d)$ so this result demonstrates that the computational threshold exactly coincides with the statistical physics phase transition thus confirming the main conjecture of [28]. We further analyze the s...

  10. Nonlinear Psychometric Thresholds for Physics and Mathematics

    CERN Document Server

    Hsu, Stephen D H

    2010-01-01

    We analyze 5 years of student records at the University of Oregon to estimate the probability of success (as defined by superior undergraduate record; sufficient for admission to graduate school) in Physics and Mathematics as a function of SAT-M score. We find evidence of a nonlinear threshold: below SAT-M score of roughly 600, the probability of success is very low. Interestingly, no similar threshold exists in other majors, such as Sociology, History, English or Biology, whether on SAT combined, SAT-R or SAT-M. Our findings have significant implications for the demographic makeup of graduate populations in mathematically intensive subjects, given the current distribution of SAT-M scores.

  11. LHC Longitudinal Single-Bunch Stability Threshold

    CERN Document Server

    Esteban Muller, Juan Federico; Baudrenghien, Philippe; Lasheen, Alexandre; Roggen, Toon; Shaposhnikova, Elena; Timko, Helga; CERN. Geneva. ATS Department

    2016-01-01

    The aim of the MD studies presented here was to determine with a reasonable accuracy the single-bunch longitudinal stability threshold in the LHC. The measurements were performed by placing along the ring 8 or 20 ‘single’ bunches with different intensities but similar longitudinal emittances. Then they were accelerated and bunch stability was observed at arrival to flat top. Combining the results of two measurement sessions, the single bunch stability threshold is estimated to be (2.4 ± 0.2) × 10^11 ppb for an emittance of 1.89 eVs (1.0 ns) at 6.5 TeV with 12 MV RF voltage. Measurements were taken during the MD session MD472 from 22:00 on 20th to 05:00 on 21st July 2015 and session MD365 from 17:00 on 26th to 01:00 on 27th August 2015.

  12. Low-Threshold Bidirectional Air Lasing

    Science.gov (United States)

    Laurain, Alexandre; Scheller, Maik; Polynkin, Pavel

    2014-12-01

    Air lasing refers to the remote optical pumping of the constituents of ambient air that results in a directional laserlike emission from the pumped region. Intense current investigations of this concept are motivated by the potential applications in remote atmospheric sensing. Different approaches to air lasing are being investigated, but, so far, only the approach based on dissociation and resonant two-photon pumping of air molecules by deep-UV laser pulses has produced measurable lasing energies in real air and in the backward direction, which is of the most relevance for applications. However, the emission had a high pumping threshold, in hundreds of GW /cm2. We demonstrate that the threshold can be virtually eliminated through predissociation of air molecules with an additional nanosecond laser. We use a single tunable pump laser system to generate backward-propagating lasing in both oxygen and nitrogen in air, with energies of up to 1 μ J per pulse.

  13. Universally Composable Proactive Threshold RSA Signature

    Institute of Scientific and Technical Information of China (English)

    HONG Xuan; CHEN Ke-fei; LONG Yu

    2008-01-01

    Recently some efforts were made towards capturing the security requirements within the composable security framework.This modeling has some significant advantages in designing and analyzing complex systems.The threshold signature was discussed and a definition was given based on the universal composability framework,which is proved to be equivalent to the standard security definition.Furthermore,a simple,efficient and proactive threshold RSA signature protocol was presented.It is proved to be correct,consistent and unforgeable relative to the environment that at most t-1 parties are corrupted in each proactive stage.It is also secure under the universal composability framework.It is a UC based security and is proved to be equivalent to the standard security.

  14. Multiparty Computation from Threshold Homomorphic Encryption

    DEFF Research Database (Denmark)

    Cramer, Ronald; Damgård, Ivan Bjerre; Nielsen, Jesper Buus

    2001-01-01

    We introduce a new approach to multiparty computation (MPC) basing it on homomorphic threshold crypto-systems. We show that given keys for any sufficiently efficient system of this type, general MPC protocols for n parties can be devised which are secure against an active adversary that corrupts...... any minority of the parties. The total number of bits broadcast is O(nk|C|), where k is the security parameter and |C| is the size of a (Boolean) circuit computing the function to be securely evaluated. An earlier proposal by Franklin and Haber with the same complexity was only secure for passive...... adversaries, while all earlier protocols with active security had complexity at least quadratic in n. We give two examples of threshold cryptosystems that can support our construction and lead to the claimed complexities....

  15. Verifiable threshold signature schemes against conspiracy attack

    Institute of Scientific and Technical Information of China (English)

    甘元驹

    2004-01-01

    In this study, the author has designed new verifiable (t, n) threshold untraceable signature schemes. The proposed schemes have the following properties: ( 1 ) Verification: The shadows of the secret distributed by the trusted center can be verified by all of the participants; (2) Security: Even if the number of the dishonest member is over the value of the threshold, they cannot get the system secret parameters , such as the group secret key, and forge other member's individual signature; (3) Efficient verification: The verifier can verify the group signature easily and the verification time of the group signature is equivalent to that of an individual signature; (4) Untraceability: The signers of the group signature cannot be traced.

  16. Verifiable threshold signature schemes against conspiracy attack

    Institute of Scientific and Technical Information of China (English)

    GAN Yuan-ju(甘元驹)

    2004-01-01

    In this study, the author has designed new verifiable (t,n) threshold untraceable signature schemes. The proposed schemes have the following properties:(1) Verification: The shadows of the secret distributed by the trusted center can be verified by all of the participants;(2) Security: Even if the number of the dishonest member is over the value of the threshold, they cannot get the system secret parameters ,such as the group secret key, and forge other member's individual signature;(3) Efficient verification: The verifier can verify the group signature easily and the verification time of the group signature is equivalent to that of an individual signature; (4) Untraceability: The signers of the group signature cannot be traced.

  17. Multiple Parton Interactions in ALICE

    CERN Document Server

    CERN. Geneva

    2013-01-01

    We will present in detail the measurement of the charged particle multiplicity dependence of per-trigger pair yields in azimuthal direction induced by low-energetic di-jets produced in proton-proton collisions. Using two-particle angular correlations with low transverse momentum thresholds, jet properties are measured on a statistical basis down to the lowest possible jet energies. The analysis can give information about the contribution from multiple parton interactions to particle production. Moreover, the results allow to optimize the parametrization of the jet fragmentation in phenomenological mode...

  18. Dielectric nanostructures with high laser damage threshold

    Science.gov (United States)

    Ngo, C. Y.; Hong, L. Y.; Deng, J.; Khoo, E. H.; Liu, Z.; Wu, R. F.; Teng, J. H.

    2017-02-01

    Dielectric-based metamaterials are proposed to be the ideal candidates for low-loss, high-efficiency devices. However, to employ dielectric nanostructures for high-power applications, the dielectric material must have a high laser-induced damaged threshold (LIDT) value. In this work, we investigated the LIDT values of dielectric nanostructures for high-power fiber laser applications. Consequently, we found that the fabricated SiO2 nanostructured lens can withstand laser fluence exceeding 100 J/cm2.

  19. Tongue Liminary Threshold Identification to Electrotactile Stimulation

    CERN Document Server

    Robineau, Fabien; Orliaguet, Jean-Pierre; Payan, Yohan

    2007-01-01

    Many applications use electrostimulation of the human skin to provide tactile sensation. The effect of electrotactile stimulations were studied on a 6x6 matrix of tactile electrodes placed on the anterior part of the tongue. The liminary threshold with continuous or discontinuous waveform and patterns with 2 or 4 electrodes was investigated. The result suggest that for energy saving and to improve the yield, it would probably be better to use discontinuous stimulation with two electrode patterns.

  20. Monolayer semiconductor nanocavity lasers with ultralow thresholds

    Science.gov (United States)

    Wu, Sanfeng; Buckley, Sonia; Schaibley, John R.; Feng, Liefeng; Yan, Jiaqiang; Mandrus, David G.; Hatami, Fariba; Yao, Wang; Vučković, Jelena; Majumdar, Arka; Xu, Xiaodong

    2015-04-01

    Engineering the electromagnetic environment of a nanometre-scale light emitter by use of a photonic cavity can significantly enhance its spontaneous emission rate, through cavity quantum electrodynamics in the Purcell regime. This effect can greatly reduce the lasing threshold of the emitter, providing a low-threshold laser system with small footprint, low power consumption and ultrafast modulation. An ultralow-threshold nanoscale laser has been successfully developed by embedding quantum dots into a photonic crystal cavity (PCC). However, several challenges impede the practical application of this architecture, including the random positions and compositional fluctuations of the dots, extreme difficulty in current injection, and lack of compatibility with electronic circuits. Here we report a new lasing strategy: an atomically thin crystalline semiconductor--that is, a tungsten diselenide monolayer--is non-destructively and deterministically introduced as a gain medium at the surface of a pre-fabricated PCC. A continuous-wave nanolaser operating in the visible regime is thereby achieved with an optical pumping threshold as low as 27 nanowatts at 130 kelvin, similar to the value achieved in quantum-dot PCC lasers. The key to the lasing action lies in the monolayer nature of the gain medium, which confines direct-gap excitons to within one nanometre of the PCC surface. The surface-gain geometry gives unprecedented accessibility and hence the ability to tailor gain properties via external controls such as electrostatic gating and current injection, enabling electrically pumped operation. Our scheme is scalable and compatible with integrated photonics for on-chip optical communication technologies.

  1. Femtosecond damage threshold of multilayer metal films

    Science.gov (United States)

    Ibrahim, Wael M. G.; Elsayed-Ali, Hani E.; Shinn, Michelle D.; Bonner, Carl E.

    2003-05-01

    With the availability of terawatt laser systems with subpicosecond pulses, laser damage to optical components has become the limiting factor for further increases in the output peak power. Evaluation of different material structures in accordance to their suitability for high-power laser systems is essential. Multi-shot damage experiments, using 110 fs laser pulses at 800 nm, on polycrystalline single layer gold films and multi-layer (gold-vanadium, and gold-titanium) films were conducted. The laser incident fluence was varied, in both cases, from 0.1 to 0.6 J/cm2. No evidence of surface damage was apparent in the gold sample up to a fluence of 0.3 J/cm2. The multilayer sample experienced the onset of surface damage at the lowest fluence value used of 0.1 J/cm2. Damage results are in contrast with the time resolved ultrafast thermoreflectivity measurements that revealed a reduction of the thermoreflectivity signal for the multilayer films. This decrease in the thermoreflectivity signal signifies a reduction in the surface electron temperature that should translate in a lower lattice temperature at the later stage. Hence, one should expect a higher damage threshold for the multilayer samples. Comparison of the experimental results with the predictions of the Two-Temperature Model (TTM) is presented. The damage threshold of the single layer gold film corresponds to the melting threshold predicted by the model. In contrast to the single layer gold film, the multi-layer sample damaged at almost one third the damage threshold predicted by the TTM model. Possible damage mechanisms leading to the early onset of damage for the multilayer films are discussed.

  2. Near threshold studies of photoelectron satellites

    Energy Technology Data Exchange (ETDEWEB)

    Heimann, P.A.

    1986-11-01

    Photoelectron spectroscopy and synchrotron radiation have been used to study correlation effects in the rare gases: He, Ne, Ar, Kr, and Xe. Two kinds of time-of-flight electron analyzers were employed to examine photoionization very close to threshold and at higher kinetic energies. Partial cross sections and angular distributions have been measured for a number of photoelectron satellites. The shake-off probability has been determined at some inner-shell resonances. 121 refs., 28 figs., 13 tabs.

  3. Compositional threshold for nuclear waste glass durability

    Energy Technology Data Exchange (ETDEWEB)

    Farooqi, Rahmatullah; Hrma, Pavel [Pohang Univ. of Science and Technology, Pohang (Korea, Republic of)

    2013-07-01

    The issue of major concern with the waste form, such as glass, is its chemical durability, I. e., the resistance to corrosion by aqueous media. A number of standard durability tests have been established for waste glasses, among which the product consistency test was selected as a criterion of HLW glass acceptability for the repository subsequently, a large PCT database has been collected containing over 1000 glasses. Such a database allows the development of models that relate PCT releases to glass is a strong function of composition, these models are used to formulate acceptable glasses in which the waste loading is maximized. Within the composition space of glasses, a distinct threshold appears to exist that separates 'good' glasses, I. e. these which are sufficiently durable, from 'bad' glasses of a low durability. According to Populate al., transition region between durable and less durable glasses lies around 2a m{sup -2} as determined by the 7-day PCT normalized B release. 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. Our study is focused on the corrosion behavior of SiO{sub 2} - B{sub 2}O{sub 3} - Na{sub 2}O - Al{sub 2}O{sub 3} - Colleagues composition region. In particular, we try to identify the durability threshold separating durable from nondurable glasses in the composition space. So far we have explored the elemental releases of Na and B measured with the 7-day PCT.

  4. Democratic Group Signatures with Threshold Traceability

    Institute of Scientific and Technical Information of China (English)

    LI Xiang-xue; QIAN Hai-feng; LI Jian-hua

    2009-01-01

    This paper presents a concrete democratic group signature scheme which holds (t, n)-threshold trace-ability. In the scheme, the capability of tracing the actual signer is distributed among n group members. It gives a valid democratic group signature such that any subset with more than t members can jointly reconstruct a secret and reveal the identity of the signer. Any active adversary cannot do this even if he can corrupt up to t - 1 group members.

  5. Measurement of ventilatory threshold by respiratory frequency.

    Science.gov (United States)

    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, pcycle) 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.

  6. Multiple Gliomas

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Multiple gliomas are well-recognized but uncommon tumors. The incidence of multiple gliomas according to some reports ranges from 0.5% to 20% of all gliomas diagnosed. Multiple gliomas can be divided into two categories. One is by location of the lesions (multifocal and multicentric). The second type is by the time of the lesions occur (synchronous and metachronous). The lesions generally show hypo, or isodensity on CT; a hypo- or isointense signal on T1-weighted images, and a hyperintense signal on T2-weighted images. Glioblastoma is the most frequent histotype. The prognosis of multiple gliomas remains unfavorable. The treatment of multiple gliomas includes surgery, radiotherapy and chemotherapy. Distinction between multicentric and multifocal gliomas is difficult. This report reviews in detail the aspects of multiple gliomas mentioned above.

  7. INVESTIGATION OF RATTLING THRESHOLD IN GEAR SYSTEM

    Institute of Scientific and Technical Information of China (English)

    Dong Haijun; Shen Yunwen; Liu Mengjun; Wang Sanmin

    2005-01-01

    A lumped mass gear-rattling model with backlash is established by considering the time varying mesh stiffness, composite transmission error and the torque fluctuation. Based on the principle that no separation will occur if the response amplitude is not larger than the static response,the threshold is obtained by theoretical derivation. The validity of the theoretical derivation is verified by the numerical method. The results show that the time-varying mesh stiffness has little effect on the threshold. When the exciting frequency is less than the system natural frequency, the theoretical agrees well with the numerical one. The higher the exciting frequency or the smaller the average input torque is, the easier the separation will occur. When the exciting frequency is larger than the natural frequency by a certain value, the theoretical threshold does not agree with the numerical results. The numerical results show that the motion state will change from the meshing state to the separating state directly. The phenomenon that the gear pair sometimes separates and sometimes meshes occurs only when the exciting frequency is smaller.

  8. Bounds on the quantum satisfibility threshold

    CERN Document Server

    Bravyi, Sergey; Russell, Alexander

    2009-01-01

    Quantum k-SAT is the problem of deciding whether there is a n-qubit state which is perpendicular to a set of vectors, each of which lies in the Hilbert space of k qubits. Equivalently, the problem is to decide whether a particular type of local Hamiltonian has a ground state with zero energy. We consider random quantum k-SAT formulas with n variables and m = \\alpha n clauses, and ask at what value of \\alpha these formulas cease to be satisfiable. We show that the threshold for random quantum 3-SAT is at most 3.594. For comparison, convincing arguments from statistical physics suggest that the classical 3-SAT threshold is \\alpha \\approx 4.267. For larger k, we show that the quantum threshold is a constant factor smaller than the classical one. Our bounds work by determining the generic rank of the satisfying subspace for certain gadgets, and then using the technique of differential equations to analyze various algorithms that partition the hypergraph into a collection of these gadgets. Our use of differential ...

  9. Threshold photodetachment spectroscopy of negative ions

    Energy Technology Data Exchange (ETDEWEB)

    Kitsopoulos, T.N.

    1991-12-01

    This thesis is concerned with the development and application of high resolution threshold photodetachment spectroscopy of negative ions. Chapter I deals with the principles of our photodetachment technique, and in chapter II a detailed description of the apparatus is presented. The threshold photodetachment spectra of I{sup {minus}}, and SH{sup {minus}}, presented in the last sections of chapter II, indicated that a resolution of 3 cm{sup {minus}1} can be achieved using our technique. In chapter III the threshold photodetachment spectroscopy study of the transition state region of I + HI and I + Di reactions is discussed. Our technique probes the transition state region directly, and the results of our study are the first unambiguous observations of reactive resonances in a chemical reaction. Chapters IV, V and VI are concerned with the spectroscopy of small silicon and carbon clusters. From our spectra we were able to assign electronic state energies and vibrational frequencies for the low lying electronics states of Si{sub n} (n=2,3,4), C{sub 5} and their corresponding anions.

  10. Threshold photoelectron spectroscopy of acetaldehyde and acrolein

    Energy Technology Data Exchange (ETDEWEB)

    Yencha, Andrew J., E-mail: ayencha@albany.edu [Department of Chemistry, University at Albany, State University of New York, Albany, NY 12222 (United States); Siggel-King, Michele R.F. [Cockcroft Institute, Sci-Tech Daresbury, Warrrington WA4 4AD (United Kingdom); Department of Physics, University of Liverpool, Liverpool L69 3BX (United Kingdom); King, George C. [Department of Physics and Astronomy and Photon Science Institute, Manchester University, Manchester M13 9PL (United Kingdom); Malins, Andrew E.R. [Cockcroft Institute, Sci-Tech Daresbury, Warrrington WA4 4AD (United Kingdom); Eypper, Marie [School of Chemistry, University of Southampton, Southampton SO17 1BJ (United Kingdom)

    2013-04-15

    Highlights: •High-resolution threshold photoelectron spectrum of acetaldehyde. •High-resolution threshold photoelectron spectrum of acrolein. •High-resolution total photoion yield spectrum of acetaldehyde. •High-resolution total photoion yield spectrum of acrolein. •Determination of vertical ionization potentials in acetaldehyde and acrolein. -- Abstract: High-resolution (6 meV and 12 meV) threshold photoelectron (TPE) spectra of acetaldehyde and acrolein (2-propenal) have been recorded over the valence binding energy region 10–20 eV, employing synchrotron radiation and a penetrating-field electron spectrometer. These TPE spectra are presented here for the first time. All of the band structures observed in the TPE spectra replicate those found in their conventional HeI photoelectron (PE) spectra. However, the relative band intensities are found to be dramatically different in the two types of spectra that are attributed to the different dominant operative formation mechanisms. In addition, some band shapes and their vertical ionization potentials are found to differ in the two types of spectra that are associated with the autoionization of Rydberg states in the two molecules.

  11. Auricular Acupressure Can Modulate Pain Threshold

    Directory of Open Access Journals (Sweden)

    Antonietta Santoro

    2015-01-01

    Full Text Available The objective of our study was to investigate if auriculotherapy (AT can modulate pain threshold. In our experiments, AT consisted of placing Vaccaria seeds over the “fingers point” of one ear. Two groups of healthy volunteers were enrolled for the study. Each subject was asked to perform an autoalgometric test developed by our group on three occasions: before, 1 hour after, AT and 24 hours after AT. Participants of the first group received a 2-minute long session of AT, while participants of the second group received a 2-minute long session of sham treatment, consisting of a puncture/massage above the skin of the neck. The autoalgometric test consisted of applying an increasing pressure with the finger-tips and finger-backs of four fingers by the subjects themselves (i.e., eight sites were evaluated against a round-shaped needle for two times: until a minimum pain sensation (first time, minimal test or a maximally tolerable pain sensation (second time, maximal test. Our results showed a significant higher pain threshold in the maximal test at 24 hours after AT compared to sham treatment. This result indicates for the first time that AT can increase pain tolerability, rather than affecting the minimal pain threshold.

  12. Explaining the length threshold of polyglutamine aggregation

    Science.gov (United States)

    De Los Rios, Paolo; Hafner, Marc; Pastore, Annalisa

    2012-06-01

    The existence of a length threshold, of about 35 residues, above which polyglutamine repeats can give rise to aggregation and to pathologies, is one of the hallmarks of polyglutamine neurodegenerative diseases such as Huntington’s disease. The reason why such a minimal length exists at all has remained one of the main open issues in research on the molecular origins of such classes of diseases. Following the seminal proposals of Perutz, most research has focused on the hunt for a special structure, attainable only above the minimal length, able to trigger aggregation. Such a structure has remained elusive and there is growing evidence that it might not exist at all. Here we review some basic polymer and statistical physics facts and show that the existence of a threshold is compatible with the modulation that the repeat length imposes on the association and dissociation rates of polyglutamine polypeptides to and from oligomers. In particular, their dramatically different functional dependence on the length rationalizes the very presence of a threshold and hints at the cellular processes that might be at play, in vivo, to prevent aggregation and the consequent onset of the disease.

  13. Threshold learning dynamics in social networks.

    Directory of Open Access Journals (Sweden)

    Juan Carlos González-Avella

    Full Text Available Social learning is defined as the ability of a population to aggregate information, a process which must crucially depend on the mechanisms of social interaction. Consumers choosing which product to buy, or voters deciding which option to take with respect to an important issue, typically confront external signals to the information gathered from their contacts. Economic models typically predict that correct social learning occurs in large populations unless some individuals display unbounded influence. We challenge this conclusion by showing that an intuitive threshold process of individual adjustment does not always lead to such social learning. We find, specifically, that three generic regimes exist separated by sharp discontinuous transitions. And only in one of them, where the threshold is within a suitable intermediate range, the population learns the correct information. In the other two, where the threshold is either too high or too low, the system either freezes or enters into persistent flux, respectively. These regimes are generally observed in different social networks (both complex or regular, but limited interaction is found to promote correct learning by enlarging the parameter region where it occurs.

  14. Treatment of threshold retinopathy of prematurity

    Directory of Open Access Journals (Sweden)

    Deshpande Dhanashree

    1998-01-01

    Full Text Available This report deals with our experience in the management of threshold retinopathy of prematurity (ROP. A total of 45 eyes of 23 infants were subjected to treatment of threshold ROP. 26.1% of these infants had a birth weight of >l,500 gm. The preferred modality of treatment was laser indirect photocoagulation, which was facilitated by scleral depression. Cryopexy was done in cases with nondilating pupils or medial haze and was always under general anaesthesia. Retreatment with either modality was needed in 42.2% eyes; in this the skip areas were covered. Total regression of diseases was achieved in 91.1% eyes with no sequelae. All the 4 eyes that progressed to stage 5 despite treatment had zone 1 disease. Major treatment-induced complications did not occur in this series. This study underscores the importance of routine screening of infants upto 2,000 gm birth weight for ROP and the excellent response that is achieved with laser photocoagulation in inducing regression of threshold ROP. Laser is the preferred method of treatment in view of the absence of treatment-related morbidity to the premature infants.

  15. Threshold foraging behavior of baleen whales

    Science.gov (United States)

    Piatt, John F.; Methven, David A.

    1992-01-01

    We conducted hydroacoustic surveys for capelin Mallotus villosus in Witless Bay, Newfoundland, Canada, on 61 days during the summers of 1983 to 1985. On 32 of those days in whlch capelin surveys were conducted, we observed a total of 129 baleen whales - Including 93 humpback Megaptera novaeangliae, 31 minke Balaenoptera acutorostrata and 5 fin whales B. phvsalus. Although a few whales were observed when capelin schools were scarce, the majority (96%) of whales were observed when mean daily capelin densities exceeded 5 schools per linear km surveyed (range of means over 3 yr: 0.0 to 14.0 schools km-1). Plots of daily whale abundance (no. h-1 surveyed) vs daily capelin school density (mean no. schools km-1 surveyed) in each summer revealed that baleen whales have a threshold foraging response to capelin density. Thresholds were estimated using a simple itterative step-function model. Foraging thresholds of baleen whales (7.3, 5.0, and 5.8 schools km-1) varied between years in relation to the overall abundance of capelin schools in the study area during summer (means of 7.2, 3.3, and 5.3 schools km-1, respectively).

  16. High-performance thresholding with adaptive equalization

    Science.gov (United States)

    Lam, Ka Po

    1998-09-01

    The ability to simplify an image whilst retaining such crucial information as shapes and geometric structures is of great importance for real-time image analysis applications. Here the technique of binary thresholding which reduces the image complexity has generally been regarded as one of the most valuable methods, primarily owing to its ease of design and analysis. This paper studies the state of developments in the field, and describes a radically different approach of adaptive thresholding. The latter employs the analytical technique of histogram normalization for facilitating an optimal `contrast level' of the image under consideration. A suitable criterion is also developed to determine the applicability of the adaptive processing procedure. In terms of performance and computational complexity, the proposed algorithm compares favorably to five established image thresholding methods selected for this study. Experimental results have shown that the new algorithm outperforms these methods in terms of a number of important errors measures, including a consistently low visual classification error performance. The simplicity of design of the algorithm also lends itself to efficient parallel implementations.

  17. Threshold control of chaotic neural network.

    Science.gov (United States)

    He, Guoguang; Shrimali, Manish Dev; Aihara, Kazuyuki

    2008-01-01

    The chaotic neural network constructed with chaotic neurons exhibits rich dynamic behaviour with a nonperiodic associative memory. In the chaotic neural network, however, it is difficult to distinguish the stored patterns in the output patterns because of the chaotic state of the network. In order to apply the nonperiodic associative memory into information search, pattern recognition etc. it is necessary to control chaos in the chaotic neural network. We have studied the chaotic neural network with threshold activated coupling, which provides a controlled network with associative memory dynamics. The network converges to one of its stored patterns or/and reverse patterns which has the smallest Hamming distance from the initial state of the network. The range of the threshold applied to control the neurons in the network depends on the noise level in the initial pattern and decreases with the increase of noise. The chaos control in the chaotic neural network by threshold activated coupling at varying time interval provides controlled output patterns with different temporal periods which depend upon the control parameters.

  18. Near threshold computing technology, methods and applications

    CERN Document Server

    Silvano, Cristina

    2016-01-01

    This book explores near-threshold computing (NTC), a design-space using techniques to run digital chips (processors) near the lowest possible voltage.  Readers will be enabled with specific techniques to design chips that are extremely robust; tolerating variability and resilient against errors.  Variability-aware voltage and frequency allocation schemes will be presented that will provide performance guarantees, when moving toward near-threshold manycore chips.  ·         Provides an introduction to near-threshold computing, enabling reader with a variety of tools to face the challenges of the power/utilization wall; ·         Demonstrates how to design efficient voltage regulation, so that each region of the chip can operate at the most efficient voltage and frequency point; ·         Investigates how performance guarantees can be ensured when moving towards NTC manycores through variability-aware voltage and frequency allocation schemes.  .

  19. Multiple isolated cutaneous plexiform schwannomas

    Directory of Open Access Journals (Sweden)

    Enas A. S. Attia

    2011-01-01

    Full Text Available Plexiform schwannoma is a rare neurogenic tumor, arising from skin and subcutaneous tissue. The presence of multiple schwannomas suggests a possible association with neurofibromatosis type 2 (NF2. A 50-year old male patient presented with multiple papulo-nodular cutaneous lesions on both arms and forearms. Histopathological examination revealed a dermal multinodular pattern of well-circumscribed masses of closely packed cells, with peripheral myxoid tissue, well-encapsulated in a thin collagenous capsule. S-100 immunohistochemical staining was diffusely and strongly positive. Neuron-specific enolase was positive, confirming a neural tissue tumor. An audiogram and Magnetic Resonance Imaging (MRI of cerebro-pontine angle showed no detected abnormality, excluding acoustic neuroma. Thus, we present a case of multiple bilateral isolated cutaneous plexiform schwannomas, not associated with NF2. Multiple plexiform schwannomas is a very rare entity, distinct from neurofibromatosis (NF, and being confined to the dermis is even more rarely reported.

  20. Right aortic arch with aberrant left innominate artery arising from Kommerell's diverticulum*

    Science.gov (United States)

    Faistauer, Ângela; Torres, Felipe Soares; Faccin, Carlo Sasso

    2016-01-01

    We report a case of an uncommon thoracic aorta anomaly-right aortic arch with aberrant left innominate artery arising from Kommerell's diverticulum-that went undiagnosed until adulthood. PMID:27777481

  1. Squamous cell carcinoma arising within a maxillary odontogenic keratocyst: A rare occurrence

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Elnaz [Eliray Oral and Maxillofacial Radiology Consulting Services, Miami (United States); Tadinada, Aditya; Rengasamy, Kandasamy; Ferneini, Elie M. [University of Connecticut, School of Dental Medicine, Farmington (United States)

    2017-06-15

    Squamous cell carcinoma (SCC) arising within the lining of an odontogenic keratocyst (OKC) is a rare occurrence. Although potentially locally destructive, OKC is a benign odontogenic process that typically presents with clinical and radiographic features characteristic of a benign intraosseous neoplasm. We present the clinical and radiographic features of a maxillary mass that demonstrated SCC arising from the lining of an OKC. Although the initial clinical and radiographic presentation suggested an infection or malignant neoplasm, biopsies revealed an infiltrative well-differentiated SCC contiguous with and arising from the focus of a pre-existing OKC. The patient subsequently underwent a type II hemi-maxillectomy with neoadjuvant chemoradiation. This report discusses the clinical and radiographic features associated with intraosseous malignancies, especially those arising from an otherwise benign odontogenic lesion. While the majority of OKCs are benign, the current report illustrates the potential for carcinomatous transformation within the lining of an OKC.

  2. A Classical Realizability Model arising from a Stable Model of Untyped Lambda Calculus

    OpenAIRE

    Streicher, Thomas

    2014-01-01

    We study a classical realizability model (in the sense of J.-L. Krivine) arising from a model of untyped lambda calculus in coherence spaces. We show that this model validates countable choice using bar recursion and bar induction.

  3. Squamous cell carcinoma arising from an epidermal cyst in the thumb

    Directory of Open Access Journals (Sweden)

    Akio Sakamoto

    2015-01-01

    Discussion and conclusion: The clinical symptoms of squamous cell carcinoma arising from an epidermal cyst can mimic those of an infected epidermal cyst. The current report facilitates awareness of such disease.

  4. A pair of Fibonacci-like polynomials arising from a special mapping

    Science.gov (United States)

    Griffiths, Martin; Griffiths, Jonny

    2016-02-01

    We study here a pair of sequences of polynomials that arise from a particular iterated mapping on the plane. We show how these sequences come about, and give some of their interesting mathematical properties.

  5. SIMILARITY REDUCTIONS FOR THE NONLINEAR EVOLUTION EQUATION ARISING IN THE FERMI-PASTA-ULAM PROBLEM

    Institute of Scientific and Technical Information of China (English)

    谢福鼎; 闫振亚; 张鸿庆

    2002-01-01

    Four families of similarity reductions are obtained for the nonlinear evolution equation arising in the Fermi-Pasta-Ulam problem via using both the direct method due to Clarkson and Kruskal and the improved direct method due to Lou.

  6. Bifurcation threshold of the delayed van der Pol oscillator under stochastic modulation.

    Science.gov (United States)

    Gaudreault, Mathieu; Drolet, François; Viñals, Jorge

    2012-05-01

    We obtain the location of the Hopf bifurcation threshold for a modified van der Pol oscillator, parametrically driven by a stochastic source and including delayed feedback in both position and velocity. We introduce a multiple scale expansion near threshold, and we solve the resulting Fokker-Planck equation associated with the evolution at the slowest time scale. The analytical results are compared with a direct numerical integration of the model equation. Delay modifies the Hopf frequency at threshold and leads to a stochastic bifurcation that is shifted relative to the deterministic limit by an amount that depends on the delay time, the amplitude of the feedback terms, and the intensity of the noise. Interestingly, stochasticity generally increases the region of stability of the limit cycle.

  7. Multi-focal lobular carcinoma in situ arising in benign phylodes tumor: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Taeg Ki; Choi, Chang Hwan; Kim, Youn Jeong; Kim, Mi Young; Lee, Kyung Hee; Cho, Soon Gu [Inha University Hospital, Incheon (Korea, Republic of)

    2015-08-15

    Coexistent breast malignancy arising in phyllodes tumor is extremely rare, and most of them are incidental reports after surgical excision. Coexistent malignancy in phyllodes tumor can vary from in-situ to invasive carcinoma. Lobular neoplasia is separated into atypical lobular hyperplasia and lobular carcinoma in situ (LCIS). LCIS is known to have a higher risk of developing invasive cancer. We reported imaging findings of multifocal LCIS arising in benign phyllodes tumor.

  8. Variational iteration method for Bratu-like equation arising in electrospinning.

    Science.gov (United States)

    He, Ji-Huan; Kong, Hai-Yan; Chen, Rou-Xi; Hu, Ming-sheng; Chen, Qiao-ling

    2014-05-25

    This paper points out that the so called enhanced variational iteration method (Colantoni & Boubaker, 2014) for a nonlinear equation arising in electrospinning and vibration-electrospinning process is the standard variational iteration method. An effective algorithm using the variational iteration algorithm-II is suggested for Bratu-like equation arising in electrospinning. A suitable choice of initial guess results in a relatively accurate solution by one or few iteration.

  9. Myoepithelial carcinoma arising in an adenomyoepithelioma of the breast: A case report of a rare entity

    Directory of Open Access Journals (Sweden)

    Khurana Anuj

    2010-04-01

    Full Text Available Adenomyoepithelioma of the breast is a rare tumor. Malignant change arising in this lesion is infrequent and only a few cases have been reported. We discuss a case of a 56-year-old female presenting with a firm breast mass, which was interpreted as myoepithelial carcinoma arising in a background of adenomyoepithelioma, based on morphological and immunohistochemical studies. This case is being highlighted for its rarity and distinct morphological spectrum.

  10. Catheter Ablation of Ventricular Arrhythmias Arising from the Distal Great Cardiac Vein.

    Science.gov (United States)

    Letsas, Konstantinos P; Efremidis, Michael; Vlachos, Konstantinos; Georgopoulos, Stamatis; Xydonas, Sotirios; Valkanas, Kosmas; Sideris, Antonios

    2016-03-01

    Catheter ablation of idiopathic ventricular arrhythmias arising from the distal great cardiac vein represents a great challenge. We report data regarding the electrocardiographic and electrophysiologic characteristics in two patients with ventricular arrhythmias arising from the distal great cardiac vein. The technical difficulties to advance and navigate the ablation catheter within the coronary venous system as well as the close proximity to the major coronary vessels are discussed.

  11. Post-transplant Lymphoproliferative Disorder Arising from Renal Allograft Parenchyma: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Byung Kwan; Kim, Chan Kyo; Kwon, Ghee Young [Samsung Medical Center, Sungkyunkwan University College of Medicine, Seoul (Korea, Republic of)

    2010-06-15

    Post-transplant lymphoproliferative disorder (PTLD) is a rare but serious complication that occurs in patients undergoing kidney transplantation. PTLD usually manifests as a renal hilar mass comprised of histologically B-lymphocytes. We report our experience of managing a patient with PTLD arising from renal parenchyma. Ultrasonographic and MR imaging features of this unusual PTLD suggested differentiated renal cell carcinoma arising from the renal allograft

  12. A Robust Threshold for Iterative Channel Estimation in OFDM Systems

    Directory of Open Access Journals (Sweden)

    A. Kalaycioglu

    2010-04-01

    Full Text Available A novel threshold computation method for pilot symbol assisted iterative channel estimation in OFDM systems is considered. As the bits are transmitted in packets, the proposed technique is based on calculating a particular threshold for each data packet in order to select the reliable decoder output symbols to improve the channel estimation performance. Iteratively, additional pilot symbols are established according to the threshold and the channel is re-estimated with the new pilots inserted to the known channel estimation pilot set. The proposed threshold calculation method for selecting additional pilots performs better than non-iterative channel estimation, no threshold and fixed threshold techniques in poor HF channel simulations.

  13. The assessment of sensory detection thresholds on the perineum and breast compared with control body sites.

    Science.gov (United States)

    Cordeau, Dany; Bélanger, Marc; Beaulieu-Prévost, Dominic; Courtois, Frédérique

    2014-07-01

    Few studies explored multiple sensory detection thresholds on the perineum and breast, but these normative data may provide standards for clinical conditions such as aging, genital and breast surgeries, pathological conditions affecting the genitals, and sexual function. The aim of this study was to provide normative data on sensory detection thresholds of three sensory modalities on the perineum and breast. Thirty healthy women aged between 18 and 35 years were assessed on the perineum (clitoris, labia minora, vaginal, and anal margin), breast (lateral, areola, nipple), and control body locations (neck, forearm, abdomen) for three sensory modalities (light touch, pressure, vibration). Average detection thresholds for each body location and sensory modality and statistical comparisons between the primary genital, secondary sexual, and neutral zones were the main outcome measures. Average detection thresholds for light touch suggest that the neck, forearm, and vaginal margin are most sensitive, and areola least sensitive. No statistical difference is found between the primary and secondary sexual zones, but the secondary sexual zone is significantly more sensitive than the neutral zone. Average detection thresholds for pressure suggest that the clitoris and nipple are most sensitive, and the lateral breast and abdomen least sensitive. No statistical difference is found between the primary and secondary sexual zone, but they are both significantly more sensitive than the neutral zone. Average detection thresholds for vibration suggest that the clitoris and nipple are most sensitive. The secondary sexual zone is significantly more sensitive than the primary and neutral zone, but the latter two show no difference. The current normative data from sensory detection threshold are discussed in terms of providing standard values for research and clinical conditions. Additional analysis from breast volume, body mass index, hormonal contraception, menstrual cycle, and sexual

  14. Using a staircase procedure for the objective measurement of auditory stream integration and segregation thresholds

    Directory of Open Access Journals (Sweden)

    Mona Isabel Spielmann

    2013-08-01

    Full Text Available Auditory scene analysis describes the ability to segregate relevant sounds out from the environment and to integrate them into a single sound stream using the characteristics of the sounds to determine whether or not they are related. This study aims to contrast task performances in objective threshold measurements of segregation and integration using identical stimuli, manipulating two variables known to influence streaming, inter-stimulus-interval (ISI and frequency difference (Δf. For each measurement, one parameter (either ISI or Δf was held constant while the other was altered in a staircase procedure. By using this paradigm, it is possible to test within-subject across multiple conditions, covering a wide Δf and ISI range in one testing session. The objective tasks were based on across-stream temporal judgments (facilitated by integration and within-stream deviance detection (facilitated by segregation. Results show the objective integration task is well suited for combination with the staircase procedure, as it yields consistent threshold measurements for separate variations of ISI and Δf, as well as being significantly related to the subjective thresholds. The objective segregation task appears less suited to the staircase procedure. With the integration-based staircase paradigm, a comprehensive assessment of streaming thresholds can be obtained in a relatively short space of time. This permits efficient threshold measurements particularly in groups for which there is little prior knowledge on the relevant parameter space for streaming perception.

  15. Modeling of ablation threshold dependence on pulse duration for dielectrics with ultrashort pulsed laser

    Science.gov (United States)

    Sun, Mingying; Zhu, Jianqiang; Lin, Zunqi

    2017-01-01

    We present a numerical model of plasma formation in ultrafast laser ablation on the dielectrics surface. Ablation threshold dependence on pulse duration is predicted with the model and the numerical results for water agrees well with the experimental data for pulse duration from 140 fs to 10 ps. Influences of parameters and approximations of photo- and avalanche-ionization on the ablation threshold prediction are analyzed in detail for various pulse lengths. The calculated ablation threshold is strongly dependent on electron collision time for all the pulse durations. The complete photoionization model is preferred for pulses shorter than 1 ps rather than the multiphoton ionization approximations. The transition time of inverse bremsstrahlung absorption needs to be considered when pulses are shorter than 5 ps and it can also ensure the avalanche ionization (AI) coefficient consistent with that in multiple rate equations (MREs) for pulses shorter than 300 fs. The threshold electron density for AI is only crucial for longer pulses. It is reasonable to ignore the recombination loss for pulses shorter than 100 fs. In addition to thermal transport and hydrodynamics, neglecting the threshold density for AI and recombination could also contribute to the disagreements between the numerical and the experimental results for longer pulses.

  16. Threshold concepts: implications for the management of natural resources

    Science.gov (United States)

    Guntenspergen, Glenn R.; Gross, John

    2014-01-01

    Threshold concepts can have broad relevance in natural resource management. However, the concept of ecological thresholds has not been widely incorporated or adopted in management goals. This largely stems from the uncertainty revolving around threshold levels and the post hoc analyses that have generally been used to identify them. Natural resource managers have a need for new tools and approaches that will help them assess the existence and detection of conditions that demand management actions. Recognition of additional threshold concepts include: utility thresholds (which are based on human values about ecological systems) and decision thresholds (which reflect management objectives and values and include ecological knowledge about a system) as well as ecological thresholds. All of these concepts provide a framework for considering the use of threshold concepts in natural resource decision making.

  17. Category 3 threshold quantities for hazard categorization of nonreactor facilities

    Energy Technology Data Exchange (ETDEWEB)

    Mandigo, R.L.

    1996-02-13

    This document provides the information necessary to determine Hazard Category 3 threshold quantities for those isotopes of interest not listed in WHC-CM-4-46, Section 4, Table 1.''Threshold Quantities.''

  18. Multiuser switched diversity scheduling systems with per-user threshold

    KAUST Repository

    Nam, Haewoon

    2010-05-01

    A multiuser switched diversity scheduling scheme with per-user feedback threshold is proposed and analyzed in this paper. The conventional multiuser switched diversity scheduling scheme uses a single feedback threshold for every user, where the threshold is a function of the average signal-to-noise ratios (SNRs) of the users as well as the number of users involved in the scheduling process. The proposed scheme, however, constructs a sequence of feedback thresholds instead of a single feedback threshold such that each user compares its channel quality with the corresponding feedback threshold in the sequence. Numerical and simulation results show that thanks to the flexibility of threshold selection, where a potentially different threshold can be used for each user, the proposed scheme provides a higher system capacity than that for the conventional scheme. © 2006 IEEE.

  19. An Activation Threshold Model for Response Inhibition

    Science.gov (United States)

    MacDonald, Hayley J.; McMorland, Angus J. C.; Stinear, Cathy M.; Coxon, James P.; Byblow, Winston D.

    2017-01-01

    Reactive response inhibition (RI) is the cancellation of a prepared response when it is no longer appropriate. Selectivity of RI can be examined by cueing the cancellation of one component of a prepared multi-component response. This substantially delays execution of other components. There is debate regarding whether this response delay is due to a selective neural mechanism. Here we propose a computational activation threshold model (ATM) and test it against a classical “horse-race” model using behavioural and neurophysiological data from partial RI experiments. The models comprise both facilitatory and inhibitory processes that compete upstream of motor output regions. Summary statistics (means and standard deviations) of predicted muscular and neurophysiological data were fit in both models to equivalent experimental measures by minimizing a Pearson Chi-square statistic. The ATM best captured behavioural and neurophysiological dynamics of partial RI. The ATM demonstrated that the observed modulation of corticomotor excitability during partial RI can be explained by nonselective inhibition of the prepared response. The inhibition raised the activation threshold to a level that could not be reached by the original response. This was necessarily followed by an additional phase of facilitation representing a secondary activation process in order to reach the new inhibition threshold and initiate the executed component of the response. The ATM offers a mechanistic description of the neural events underlying RI, in which partial movement cancellation results from a nonselective inhibitory event followed by subsequent initiation of a new response. The ATM provides a framework for considering and exploring the neuroanatomical constraints that underlie RI. PMID:28085907

  20. The Electromyographic Threshold in Girls and Women.

    Science.gov (United States)

    Long, Devon; Dotan, Raffy; Pitt, Brynlynn; McKinlay, Brandon; O'Brien, Thomas D; Tokuno, Craig; Falk, Bareket

    2017-02-01

    The electromyographic threshold (EMGTh) is thought to reflect increased high-threshold/type-II motor-unit (MU) recruitment and was shown higher in boys than in men. Women differ from men in muscular function. Establish whether females' EMGTh and girls-women differences are different than males'. Nineteen women (22.9 ± 3.3yrs) and 20 girls (10.3 ± 1.1yrs) had surface EMG recorded from the right and left vastus lateralis muscles during ramped cycle-ergometry to exhaustion. EMG root-mean-squares were averaged per pedal revolution. EMGTh was determined as the least residual sum of squares for any two regression-line data divisions, if the trace rose ≥ 3SD above its regression line. EMGTh was expressed as % final power-output (%Pmax) and %VO2pk power (%PVO2pk). EMGTh was detected in 13 (68%) of women, but only 9 (45%) of girls (p girls (%Pmax= 88.6 ± 7.0 vs. 83.0 ± 6.9%, p = .080; %PVO2pk= (101.6 ± 17.6 vs. 90.6 ± 7.8%, p = .063). When EMGTh was undetected it was assumed to occur at 100%Pmax or beyond. Consequently, EMGTh values turned significantly higher in girls than in women (94.8 ± 7.4 vs. 88.4 ± 9.9%Pmax, p = .026; and 103.2 ± 11.7 vs. 95.2 ± 9.9%PVO2pk, p = .028). During progressive exercise, girls appear to rely less on higher-threshold/type-II MUs than do women, suggesting differential muscle activation strategy.

  1. Threshold power and energy confinement for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Takizuka, T.

    1996-12-31

    In order to predict the threshold power for L-H transition and the energy confinement performance in ITER, assembling of database and analyses of them have been progressed. The ITER Threshold Database includes data from 10 divertor tokamaks. Investigation of the database gives a scaling of the threshold power of the form P{sub thr} {proportional_to} B{sub t} n{sub e}{sup 0.75} R{sup 2} {times} (n{sub e} R{sup 2}){sup +-0.25}, which predicts P{sub thr} = 100 {times} 2{sup 0{+-}1} MW for ITER at n{sub e} = 5 {times} 10{sup 19} m{sup {minus}3}. The ITER L-mode Confinement Database has also been expanded by data from 14 tokamaks. A scaling of the thermal energy confinement time in L-mode and ohmic phases is obtained; {tau}{sub th} {approximately} I{sub p} R{sup 1.8} n{sub e}{sup 0.4{sub P{sup {minus}0.73}}}. At the ITER parameter, it becomes about 2.2 sec. For the ignition in ITER, more than 2.5 times of improvement will be required from the L-mode. The ITER H-mode Confinement Database is expanded from data of 6 tokamaks to data of 11 tokamaks. A {tau}{sub th} scaling for ELMy H-mode obtained by a standard regression analysis predicts the ITER confinement time of {tau}{sub th} = 6 {times} (1 {+-} 0.3) sec. The degradation of {tau}{sub th} with increasing n{sub e} R{sup 2} (or decreasing {rho}{sub *}) is not found for ELMy H-mode. An offset linear law scaling with a dimensionally correct form also predicts nearly the same {tau}{sub th} value.

  2. Tissue damage thresholds during therapeutic electrical stimulation

    Science.gov (United States)

    Cogan, Stuart F.; Ludwig, Kip A.; Welle, Cristin G.; Takmakov, Pavel

    2016-04-01

    Objective. Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. Approach. In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. Main results. For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. Significance. It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device

  3. A regional landslide warning system based on spatially variable rainfall thresholds

    Science.gov (United States)

    Segoni, Samuele; Rossi, Guglielmo; Rosi, Ascanio; Catani, Filippo

    2010-05-01

    -gauge registration, the critical Intensity (I) and Duration (D) of the triggering event, its return time and the amount of antecedent rain; ii) Designating the most proper rain-gauge to represent every single landslide (the choice is performed combining geographic position and return times of the recorded rainfall); iii) Plotting the corresponding ID values on a log-log graph. iv) Automatic drawing of the rainfall threshold using a geometric criterion (lower-bound line of the plotted points) or a statistical predictor. By means of this automated procedure, multiple thresholds (differentiated on the basis of the severity of the event or the amount of antecedent rain) can be defined and different alarm levels set up. Varying the criteria the automated analysis is based upon, different thresholds can be obtained, all of them calibrated only with the past rainfalls that did trigger landslides. To select the most effective one, a calibration based upon rainfalls not connected with landslides was also performed: the 8-years rain-gauges measurements were compared to the thresholds and the one which minimizes the false positives (rainfall events beyond the threshold without associated landslides) was chosen to represent the rainfall conditions that should trigger landslides in that alert zone. This procedure allows to balance the thresholds between false positives (occurring when a threshold is too low) and missed alarms (related to excessively high thresholds). The results have been validated using rainfall registrations and landslides occurred during the period 2008 - 2009. Results were quite satisfactory and therefore the thresholds will soon be combined into a standard open procedure with a high degree of automation for the use of civil protection agencies in Tuscany.

  4. The AMS-01 Aerogel Threshold Cherenkov counter

    Energy Technology Data Exchange (ETDEWEB)

    Barancourt, D.; Barao, F.; Barbier, G.; Barreira, G.; Buenerd, M.; Castellini, G.; Choumilov, E.; Favier, J.; Fouque, N.; Gougas, A.; Hermel, V.; Kossakowski, R.; Laborie, G.; Laurenti, G.; Lee, S.-C.; Mayet, F. E-mail: frederic.mayet@isn.in2p3.fr; Meillon, B.; Oyang, Y.-T.; Plyaskin, V.; Pojidaev, V.; Rossin, C.; Santos, D.; Vezzu, F.; Vialle, J.P

    2001-06-11

    The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6 deg. orbit and at altitudes ranging between 320 and 390 km, on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold Cherenkov counter (ATC) to separate p-bar from e{sup -} and e{sup +} from p, for momenta below 3.5 GeV/c. This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

  5. The AMS-01 Aerogel Threshold Cherenkov counter

    CERN Document Server

    Barancourt, D; Barbier, G; Barreira, G; Buénerd, M; Castellini, G; Choumilov, E; Favier, Jean; Fouque, N; Gougas, Andreas; Hermel, V; Kossakowski, R; Laborie, G; Laurenti, G; Lee, S C; Mayet, F; Meillon, B; Oyang, J Y T; Plyaskin, V; Pozhidaev, V; Rossin, C; Santos, D; Vezzu, F; Vialle, J P

    2001-01-01

    The Alpha Magnetic Spectrometer in a precursor version (AMS-01), was flown in June 1998 on a 51.6 degrees orbit and at altitudes ranging between 320 and 390 km, on board of the space shuttle Discovery (flight STS-91). AMS-01 included an Aerogel Threshold Cherenkov counter (ATC) to separate antiprotons from electrons and positrons from protons, for momenta below 3.5 GeV/c. This paper presents a description of the ATC counter and reports on its performances during the flight STS-91.

  6. CLASSICAL RISK MODEL WITH THRESHOLD DIVIDEND STRATEGY

    Institute of Scientific and Technical Information of China (English)

    Zhou Ming; Guo Junyi

    2008-01-01

    In this article, a threshold dividend strategy is used for classical risk model.Under this dividend strategy, certain probability of ruin, which occurs in case of constant barrier strategy, is avoided. Using the strong Markov property of the surplus process and the distribution of the deficit in classical risk model, the survival probability for this model is derived, which is more direct than that in Asmussen(2000, P195, Proposition 1.10). The occupation time of non-dividend of this model is also discussed by means of Martingale method.

  7. Threshold Neutral Pion Photoproduction on the Proton

    CERN Document Server

    Blin, Astrid Hiller; Ledwig, Tim

    2015-01-01

    The neutral pion photoproduction on the proton near threshold has a very small scattering cross section when compared to the charged channels, which in ChPT is explained by strong cancellations between the lowest order pieces. Therefore it is very sensitive to higher-order corrections of chiral perturbation theory. We perform a fully covariant calculation up to chiral order p^3 and we investigate the effect of the inclusion of the Delta(1232) resonance as an explicit degree of freedom. We show that the convergence improves, leading to a much better agreement with data at a wide range of energies.

  8. Threshold corrections in heterotic flux compactifications

    CERN Document Server

    Angelantonj, Carlo; Sarkis, Matthieu

    2016-01-01

    We compute the one-loop threshold corrections to the gauge and gravitational couplings for a large class of N=2 non-K\\"ahler heterotic compactifications with three-form flux, consisting in principal two-torus bundles over K3 surfaces. We obtain the results as sums of BPS-states contributions, depending on the topological data of the bundle. We analyse also the worldsheet non-perturbative corrections coming from instantons wrapping the torus fiber, that are mapped under S-duality to D-instanton corrections in type I flux compactifications.

  9. Near Threshold Coincident Electrofission of Uranium -238.

    Science.gov (United States)

    Dowell, David Harry

    Using the 100% duty cycle electron beam from the University of Illinois MUSL-2 accelerator, inelastic electron scattering form factors have been measured in coincidence with the fission decay of ('238)U. Data was taken at effective elastic momentum transfers of .36, .41 .45 and .59 fm(' -1) and electron-fission fragment angular correlations were measured perpendicular to and along the momentum transfer axis. The beam energies used were 67.11, 56.91 and 46.49 MeV, with the outgoing electron detected at 60(DEGREES) and 80(DEGREES), relative to the beam direction. The electron energy resolution was .1% and the form factors were measured for excitation energies from 2 to 12 MeV. Thin films of scintillator plastic (.5 mg/cm('2)) were used to detect the fission fragments from a 1 mg/cm('2) UF(,4) target evaporated onto a .240 mg/cm('2) aluminum backing. A prominent, anisotropic threshold peak is seen in the coincident form factors. An analysis of the q-dependence of the data and of the angular correlation indicates the observed strength is E2. Fission threshold for this E2 strength is about 5.7 MeV as compared with 6 MeV for E1 decays. The peak itself is due to the onset of neutron competition at 6.15 MeV. The threshold region, when analyzed using a Gaussian K-distribution to describe the statistical density of K -states near the fission barrier, exhibits a step-like change in the value of K(,0)('2) at .7 MeV above threshold. This indicates a possible energy gap in the E2 transition states. The decay is isotropic above 7.5 MeV excitation energy. From 7 to 11.7 MeV, the distribution of E2/EO strength is relatively flat with the total strength in this region exhausting approximately 10% of an energy weighted sum rule. A comparison with hadron scattering experiments suggests that some of the strength near 11.5 MeV is due to the fission decay of the giant monopole resonance with a fission probability similar to that of E2 transitions.

  10. Temporal dynamics of hydrological threshold events

    Directory of Open Access Journals (Sweden)

    G. S. McGrath

    2007-01-01

    Full Text Available The episodic nature of hydrological flows such as surface runoff and preferential flow is a result of the nonlinearity of their triggering and the intermittency of rainfall. In this paper we examine the temporal dynamics of threshold processes that are triggered by either an infiltration excess (IE mechanism when rainfall intensity exceeds a specified threshold value, or a saturation excess (SE mechanism governed by a storage threshold. We use existing and newly derived analytical results to describe probabilistic measures of the time between successive events in each case, and in the case of the SE triggering, we relate the statistics of the time between events (the inter-event time, denoted IET to the statistics of storage and the underlying water balance. In the case of the IE mechanism, the temporal dynamics of flow events is found to be simply scaled statistics of rainfall timing. In the case of the SE mechanism the time between events becomes structured. With increasing climate aridity the mean and the variance of the time between SE events increases but temporal clustering, as measured by the coefficient of variation (CV of the IET, reaches a maximum in deep stores when the climatic aridity index equals 1. In very humid and also very arid climates, the temporal clustering disappears, and the pattern of triggering is similar to that seen for the IE mechanism. In addition we show that the mean and variance of the magnitude of SE events decreases but the CV increases with increasing aridity. The CV of IETs is found to be approximately equal to the CV of the magnitude of SE events per storm only in very humid climates with the CV of event magnitude tending to be much larger than the CV of IETs in arid climates. In comparison to storage the maximum temporal clustering was found to be associated with a maximum in the variance of soil moisture. The CV of the time till the first saturation excess event was found to be greatest when the initial

  11. Temporal dynamics of hydrological threshold events

    Directory of Open Access Journals (Sweden)

    G. S. McGrath

    2006-09-01

    Full Text Available The episodic nature of hydrological flows such as surface runoff and preferential flow is a result of the nonlinearity of their triggering and the intermittency of rainfall. In this paper we examine the temporal dynamics of threshold processes that are triggered by either an infiltration excess (IE mechanism when rainfall intensity exceeds a specified threshold value, or a saturation excess (SE mechanism governed by a storage threshold. We analytically derive probabilistic measures of the time between successive events in each case, and in the case of the SE triggering, we relate the statistics of the time between events to the statistics of storage and the underlying water balance. In the case of the IE mechanism, the temporal dynamics of flow events is shown to be simply scaled statistics of rainfall timing. In the case of the SE mechanism the time between events becomes structured. With increasing climate aridity the mean and the variance of the time between SE events increases but temporal clustering, as measured by the coefficient of variation (CV of the inter-event time, reaches a maximum in deep stores when the climatic aridity index equals 1. In very humid and also very arid climates, the temporal clustering disappears, and the pattern of triggering is similar to that seen for the IE mechanism. In addition we show that the mean and variance of the magnitude of SE events decreases but the CV increases with increasing aridity. The CV of inter-event times is found to be approximately equal to the CV of the magnitude of SE events per storm only in very humid climates with the CV of event magnitude tending to be much larger than the CV of inter-event times in arid climates. In comparison to storage the maximum temporal clustering was found to be associated with a maximum in the variance of soil moisture. The CV of the time till the first saturation excess event was found to be greatest when the initial storage was at the threshold.

  12. Cherenkov radiation threshold in random inhomogeneous media

    CERN Document Server

    Grichine, V M

    2009-01-01

    Cherenkov radiation in media with random inhomogeneities like aerogel or Earth atmosphere is discussed. The spectral-angular distribution of Cherenkov photons emitted by relativistic charged particle and averaged over the dielectric permittivity fluctuations shows angular broadening similarly to the case of media with the photon absorption. The broadening results in the smoothing of Cherenkov threshold, and therefore media with strong photon scattering have more extended dependence of Cherenkov light output on the particle speed. It can be potentially used for the particle identification

  13. Threshold fracture energy in solid particle erosion

    CERN Document Server

    Argatov, I I; Petrov, Yu V

    2012-01-01

    The effect of geometrical shape of eroding absolutely rigid particles on the threshold rate of failure has been studied. The Shtaerman-Kilchevsky theory of quasi-static blunt impact, which generalizes Hertz's classical impact theory, is used for modeling the frictionless contact interaction of an axially-symmetric particle with an elastic half-space. The incubation time fracture criterion is applied for predicting surface fracture. It is shown that there exist a critical value of the particle shape parameter such that for all its lower values the fracture energy possesses a nonzero minimal value.

  14. Level reduction and the quantum threshold theorem

    Science.gov (United States)

    Aliferis, Panagiotis (Panos)

    Computers have led society to the information age revolutionizing central aspects of our lives from production and communication to education and entertainment. There exist, however, important problems which are intractable with the computers available today and, experience teaches us, will remain so even with the more advanced computers we can envision for tomorrow.Quantum computers promise speedups to some of these important but classically intractable problems. Simulating physical systems, a problem of interest in a diverse range of areas from testing physical theories to understanding chemical reactions, and solving number factoring, a problem at the basis of cryptographic protocols that are used widely today on the internet, are examples of applications for which quantum computers, when built, will offer a great advantage over what is possible with classical computer technology.The construction of a quantum computer of sufficient scale to solve interesting problems is, however, especially challenging. The reason for this is that, by its very nature, operating a quantum computer will require the coherent control of the quantum state of a very large number of particles. Fortunately, the theory of quantum error correction and fault-tolerant quantum computation gives us confidence that such quantum states can be created, can be stored in memory and can also be manipulated provided the quantum computer can be isolated to a sufficient degree from sources of noise.One of the central results in the theory of fault-tolerant quantum computation, the quantum threshold theorem shows that a noisy quantum computer can accurately and efficiently simulate any ideal quantum computation provided that noise is weakly correlated and its strength is below a critical value known as the quantum accuracy threshold. This thesis provides a simpler and more transparent non-inductive proof of this theorem based on the concept of level reduction. This concept is also used in proving the

  15. Boolean analysis of addition and multiplication

    Energy Technology Data Exchange (ETDEWEB)

    Faltin, F. (Cornell Univ., Ithaca, NY); Metropolis, N.; Ross, B.; Rota, G.-C.

    1977-01-01

    The notions of binary string and binary symmetric function are introduced, and basic results presented. Boolean algorithms are given for binary addition and multiplication. An analysis of the redundancies involved is straightforward. The examination of carry propagation which arises in the Boolean analysis of functions may lead to a new interpretation of the notion of computational complexity.

  16. Multiple homicides.

    Science.gov (United States)

    Copeland, A R

    1989-09-01

    A study of multiple homicides or multiple deaths involving a solitary incident of violence by another individual was performed on the case files of the Office of the Medical Examiner of Metropolitan Dade County in Miami, Florida, during 1983-1987. A total of 107 multiple homicides were studied: 88 double, 17 triple, one quadruple, and one quintuple. The 236 victims were analyzed regarding age, race, sex, cause of death, toxicologic data, perpetrator, locale of the incident, and reason for the incident. This article compares this type of slaying with other types of homicide including those perpetrated by serial killers. Suggestions for future research in this field are offered.

  17. Integration of community structure data reveals observable effects below sediment guideline thresholds in a large estuary.

    Science.gov (United States)

    Tremblay, Louis A; Clark, Dana; Sinner, Jim; Ellis, Joanne I

    2017-09-20

    The sustainable management of estuarine and coastal ecosystems requires robust frameworks due to the presence of multiple physical and chemical stressors. In this study, we assessed whether ecological health decline, based on community structure composition changes along a pollution gradient, occurred at levels below guideline threshold values for copper, zinc and lead. Canonical analysis of principal coordinates (CAP) was used to characterise benthic communities along a metal contamination gradient. The analysis revealed changes in benthic community distribution at levels below the individual guideline values for the three metals. These results suggest that field-based measures of ecological health analysed with multivariate tools can provide additional information to single metal guideline threshold values to monitor large systems exposed to multiple stressors.

  18. Rainfall threshold for hillslope outflow: an emergent property of flow pathway connectivity

    Directory of Open Access Journals (Sweden)

    P. Lehmann

    2007-01-01

    Full Text Available Nonlinear relations between rain input and hillslope outflow are common observations in hillslope hydrology field studies. In this paper we use percolation theory to model the threshold relationship between rainfall amount and outflow and show that this nonlinear relationship may arise from simple linear processes at the smaller scale. When the rainfall amount exceeds a threshold value, the underlying elements become connected and water flows out of the base of the hillslope. The percolation approach shows how random variations in storage capacity and connectivity at the small spatial scale cause a threshold relationship between rainstorm amount and hillslope outflow. As a test case, we applied percolation theory to the well characterized experimental hillslope at the Panola Mountain Research Watershed. Analysing the measured rainstorm events and the subsurface stormflow with percolation theory, we could determine the effect of bedrock permeability, spatial distribution of soil properties and initial water content within the hillslope. The measured variation in the relationship between rainstorm amount and subsurface flow could be reproduced by modelling the initial moisture deficit, the loss of free water to the bedrock, the limited size of the system and the connectivity that is a function of bedrock topography and existence of macropores. The values of the model parameters were in agreement with measured values of soil depth distribution and water saturation.

  19. Static and Transient Cavitation Threshold Measurements for Mercury

    Energy Technology Data Exchange (ETDEWEB)

    Moraga, F.; Taleyarkhan, R.P.

    1999-11-14

    Transient and static cavitation thresholds for mercury as a function of the cover gas (helium or air), and pressure are reported. Both static and transient cavitation onset pressure thresholds increase linearly with cover gas pressure. Additionally, the cavitation thresholds as a function of dissolved gases were also measured and are reported.

  20. Multiple myeloma.

    LENUS (Irish Health Repository)

    Collins, Conor D

    2012-02-01

    Advances in the imaging and treatment of multiple myeloma have occurred over the past decade. This article summarises the current status and highlights how an understanding of both is necessary for optimum management.